🚨 *Addendum* 🚨 - "Why not fix the laser and just move the stage under the laser?" It's a good question! Speed mostly, it's generally a lot slower to draw the pattern with a mechanical stage, particularly if you need a lot of "flood fill" regions. And in theory a galvo can give very small resolution even if the laser spot is relatively large. I.e. you could position a 2 micron line (due to 2um spot size) 200nm away from another line. Depends on the quality of a stage, but precise movements of a large stage are a lot harder than precise rotations of a lightweight mirror, especially considering backlash and such on the stage. But it's a totally viable technique, and I might try it if I can't make the galvo behave. 🙂 - "Why direct-write laser instead of DLP chip?" No particular reason (my first attempt years ago was with a pico projector actually), I just wanted to try the direct-laser approach. There are some pros/cons to each. With DLP you run into limitations with pixel size quickly, which means you need correspondingly better optics to continue reducing feature size. Direct write laser can "scale" in that aspect a lot cheaper: a good clean beam passed through a 60x objective could theoretically hit sub-micron features. OTOH, you have to deal with issues like the galvo linearity/stability. So different trade offs. You can find commercial devices of both varieties competing in the same space for example :)
Thank you for the considered answer! Have you also thought about using a Wicked Lasers LaserCube? Its blue diode is 1300mW at 445nm, which is within the range (350nm-450nm) specified by Microposit's datasheet.
Is there any way you can see how far off the laser is coming out of the galvo and just use the stage to correct it? You could try to make the lines straighter and maybe even see if for some reason it's repeatably off mark the same amounts in when doing similar things? Kind of like how the Shaper Origin handheld cnc router uses a small but accurate cnc to improve the positioning you do by hand.
Like fgbhrl suggested flexure xyz stages can be very precise, zero backlash, readily characterized and driven by very standard gcode. Any speed lost due to greater inertial mass may be offset by running many parallel beams at once. You could even make mirror images cut at the same time that would register perfectly with their counterparts - which may be useful somehow in the construction of MEMS devices. Another argument for using a mechanical stage is that your beams (and thus the walls of your resist) could be made to be exclusively perpendicular to the substrate rather than all converging at the microscope lens.
I mean, you already have a sub-micron stepping stage, you just had to make a spatial filter for your laser and half a decent focusing optics to get better results with less effort... Also, is your laser polarized, and was the dichroic designed to work at 45°? Most of the off-the-shelf dichroic are designed to work at normal incidence and suffer big degradation in performance at high angle, especially if the laser is polarized in the wrong direction
Nice project Zach! I've got a remark: given the resolution of your patterns, your resist layer thickness is at least several microns. Generally, you don't need that kind of thickness if you want to do subsequent etching. Using a resist layer thickness of less than 300nm will improve your image definition dramatically, because fully exposing a thick layer of photoresist in a very short time all the way to the bottom is very difficult. This is because of the optical density at the laser wavelength and the fact that photobleaching of the photosensitive component isn't instantaneous.
Thanks for the tips, that's great to know! I wasn't really sure what thickness to be aiming for, so just chose an arbitrary speed near from the datasheet (3500RPM) and left it constant so there was one less variable to think about. Good news is that it seems pretty consistent, around 1.7-2um each time. I'll try increasing the speed and get a thinner layer for my next tests, thanks!
@@BreakingTaps if 2um is your thickness at 3500rpm, then increasing RPMs is probably not going to give you a significantly thinner layer. Adding a little solvent is a better strategy. Or alternatively you could use a resist like az1505.
Hm yeah, the datasheet maxes out with 500nm @ 7000 RPM. My coater should be able to hit that, I'll give it a shot and see. Good idea about adding some solvent. Will look into AZ1505! I've been wanting to get some SU8 as well, just because it looks very useful for "structural" applications where the resist is left in place.
@@BreakingTaps Be careful with exposed SU8! This stuff is ridiculously hard to remove, nearly had to scrap several fully structured 8" MEMS wafer because someone was curious about my stuff and opened the box outside the yellow light area... (partially my fault because I stored the box outside the litho area, but the stepper was down and all shelfs were full). The thickness of 150µm wasn't helping this either. Warm acetone or NMP over several hours followed by plasma ashing in a O2/Ar plasma somewhat removed it (I also read that warm Piranha solution makes quick process of the SU8 but would have definitely destroyed my wafer) . At least some devices survived.
I find this channel to be a great compliment to Applied Science. Both channels are doing really complicated things in a home shop, things that you would think would stay in the lab environment.
This guy is doing some crazy work I would never have dreamed could be approached in a DIY setup. The other channel I have seen that blew my mind in this regard is Thought Emporium.
Neato! I'm impressed with the quality you were able to get out of an old 3d printer mirror box. What kind of setup are you hoping to replace it with? some "better" COTS part, or a homebrew with a mirror bolted to a few piezos or something? Hmmm... are piezos too small for this? it looked like your angular range was actually pretty big. Actually I guess that scaling is a separate question - when you had the "demo raster" running while you walked through the beam path, the lateral displacement of the beam was on the order of mm. How many microns across the surface was that once sent through the rest of the optics and microscope objective and whatnot?
Thanks! I'm not sure what v2 will look like to be honest. The deflections are pretty big (+/- 20degrees? something like that), but that could be changed... I was trying to maximize the full range of the galvos because I figured they would not have much accuracy if trying to make very small deviations. If the a piezo galvo or whatever had very small range, we can tweak the focal distances in the relay system to make it work, probably just with much longer focal distances. I have a few options that I'm thinking about: - Getting a better galvo, the "digital" ones designed for etching should be tuned better. - Some kind of tip/tilt flexure mechanism, actuated by voice coils or high TPI threads or something. I don't _technically_ need all the speed of the galvo, so we can use a slightly slower mechanism too - a few different more "mechanical" designs (coupling a ballscrew to a rotary mechanism), so we can take advantage of high resolution in the ballscrew mechanism - A sorta silly idea someone mentioned on Discord which is growing on me: a CoreXY style 3d printer mechanism that "rasters" above the tube lens in the system, replacing the galvo entirely. Similar to how CO2 laser cutters have a traveling mirror, but coupled into a microscope objective. Still mulling that one over. - Or just admitting defeat and using the wafer stepper for all motions. Would be very slow though. The "demo raster" was an "X" shape and just about filled the entire field of view (I used it to help align various components). It depends where you look, but on the first lens it travels a few mm, on the second lens it's traveling a centimeter or two. And ultimately the FOV is either 2x2mm (20x objective) or 500x500um (40x objective).
I suggest looking either for proper galvos (like for actually your purpose) or to keep in mind that the mirror surface of your galvos has optical quality. I assume the galvos you used don't actually have the needed surface quality and that this might create the "wobbly" structure of your trial structures. Just a suggestion from my side - I hope I'm not too late 😅
@@1xBublex1 theoretically if error is repeatable u could calibrate wobble into "control system". But yeah if there is huge variation and bad repeatability is another case.
This is some serious DIY. The fact that you are creating the beginnings of an Integrated Circuit with off the shelf hardware and 3d printed parts is seriously impressive.
Another awesome video and project! I have no doubt that you’ll get it all working flawlessly. Imagine making MEMS devices in a home shop…. Good grief. You and Applied Science are always pushing the limits, and I love it!
Powered by project-ADHD 😂 I usually have 3-4 projects going at once, and when I get bored or burnt out I switch to a different one :) This project for example was 90% done in January but I just couldn't make myself finish, so went off to do other things until I got interested again :)
You've got to look into green lithography technology. I covered some in my quantum hardware lecture series on QuantumGrad. Basically, egg whites diluted with water can function as a polymer photoresist and even e-beam resist. This means that egg whites can serve as resist material for both micron and nano scale features. Plus, it's non-toxic : D
Absolutely beautiful work, very, very nice! :-) Yeah, diode laser beam quality is beyond poor. If you want maximum available power and a nice clean beam, have you considered fiber coupling the diode? The beam focused into the end of a nice length of Silica SMA905 fiber, will yield a really nice Gaussian beam profile, plus you can run the fiber wherever you want it...
Thanks Les, means a lot coming from an actual optical and laser expert! :) I haven't really looked into fiber coupling to be honest, and no real reason either, just didn't ocurr to me 🙂 Can you couple in multiple wavelengths to a fiber (so I can also include the red focusing laser)? I assume I'd need a single mode fiber instead of the bigger multi-mode stuff? Thanks for the help! My fiber-fu is pretty weak 😅
@@BreakingTaps I've never done it but I believe so. You'll have to make sure that the fiber is rated for the range of wavelengths used. You also need a lens that optimally couples the free space laser to the single mode fiber. Newport has a good article on this if you search for "Fiber Optic Coupling".
Hey, confocal microscopy guy here! I'm super impressed with what you managed to do diy with a super low budget. Before blaming galvos, try to see if the unreliability is due to vibrations: they can be absolutely awful, especially in a setup suspended from the table, and with those long 3d printed parts holding heavy optics and metal parts. If you can, try to launch an etching experiment remotely from a pc in another room, consider doing it at night if you are close to a busy road/railway, and if you are not at the ground floor. If the result is much better, it's probably you whole setup wobbling about as you walk, talk, even breathe around it. Better yet, use your extra focusing optical path behind the dichroic to get a microscopy image of a sample on a camera with some decent frame rate (30 fps is enough), if you have vibrations, it will be extremely noticeable. Also, you can gain a lot of power (if you need it) by focusing the laser on the pinhole, instead of just placing the pinhole in the collimated beam path. As long as the resolution of the lens you use is worse than the size of the pinhole, you should still get a very clean beam out of it, it will just be more finnicky to align.
Thanks for the tips, appreciate getting help from actual experts! Yeah I definitely think vibration is playing a role, although I might have underestimated how much. v2 will probably sit on a granite plate, and I might put some kind of air damper underneath to help with vibrations just to rule it out. That's a clever tip with the camera, will keep that in mind! And re: laser, I probably explained it poorly. The diode has an integral lens which is focused onto the pinhole, so the efficiency isn't as bad as it seems. But I have the pinhole intentionally misaligned because the aberration from a misaligned pinhole ended up giving better results than full intensity through the too-large-pinhole. That's why the ultimate spot ended up looking so dim. :)
Fantastic ..I worked on optics back in the day .I get surprise about all kinds of new solutions ,that are already available this days .20 year ago something like you have put together will be very ,very expensive ..And only corporations or universities will be able to afford .To see you doing this type of research is a great accomplishment !!
Nice project! I built the DLP version of this a few years ago, using a UV light engine and a wafer inspection microscope, rigged to step and repeat. Pretty good results at comparable resolution, although with some imperfections on the tiling.
It looks like the waves are mostly due to the galvo controller. My light Show laser (unity elite pro3) was wavy similar to yours until I aligned it using the potentiometers on controller board. Basically projecting a grid test pattern with pangolin quickshow software and adjusted the controllers until the corners are as close to square as possible. I'm fairly new to pro lasers but these adjustments solved my wavy problems
@BreakingTaps I can't wait 🙂 maby one day you can build layers and increase the number of transistors in short a true integrated circuit with 3d scaffolding. I recently came across this channel, and the few videos I have seen are extremely impressive. I look forward to supporting this channel any way I can. I'll be in suspense until your next video. Thank you 👍
Way fun and interesting! It is super nice to experience new ideas and principals from a source that elucidates these concepts so understandingly in both general idea and detail. Seriously, well done.
Another incredible video, as usual. Blows my mind what "home makers" are capable of, these days. Keep up the great work, looking forward to seeing more in the future!
huygens spheres are problematic with singular rays that can't actually exist. as in, they only exist because the beam is much thicker than the wavelength but its wave structure is inconvenient to visualize and it also causes inevitable diversion over distance.
homemade slicon cpu when? you have tried silicon doping, you have the laser machine.... also your channel is awesome i guess i now have a project to follow on this channel for the forseable years to come
Really nicely done. I use SU-8 spinned on a Si wafer in combination with a 365nm Led and a pattern printed on a transparancy (outsourced to a specialized printing company cost around €20 for an A4). Placed the transparancy on the wafer with a thick piece of UV tranparant glass. Expose and develop. Very high aspect ratio's possible with a spatial resolution down to 3-5 micrometers.
@@arguetav ProArt BV in Groningen, The Netherlands. Ask for film with high density in black/white. Transparant for UV and black silver blocks UV. Resolution in micrometers. Just give them a call and discuss your needs.
Great project, thank you! I'm thankful there are folks like you around. If society ever collapses, you're the kind of guy who will help build everything back. (Sorry if I have a depressing opinion of our world and where it's going, but you at least give me hope.)
Have you seen Robin Renzetti on TH-cam? He mostly does very precise machining, stuff like machine spindles. He also machines his own surface plates and measures them for flatness with an autocollimator. To do this, he made custom mirror mounts, and I think you'd like his kinematic mounts. He made a custom differential screw to get better resolution when adjusting the mirrors. Maybe something there would help you out? Very nice videos, keep them up!
I love Robin! That man has so much knowledge packed into his head it's amazing. Not sure I saw the custom mirror mounts though, will go dig through his videos to find it. Thanks for the tip!
in a past I replace galvos(rotation will be always limited by angle step) with XY positioning movement system. Similar to XY CNC light router/plasma cutter etc. The laser beam come to X mirror which you can make X movement and then to Y mirror. You need a bigger lens after XY positioning system, but resolution can go up to 100 nm. Have you tried ?
Amazing work, subscribed. Reminds me of taking image stacks through the microscope, Driven by steppers it was move, wait for vibration to stop, open shutter, wait for vibration to stop,flash led light, close shutter. Had to move it from an attic to a cellar due to vibrations. The frame wasn't sturdy but with the right setup it worked very well, these vibrations are always there however big the machine. three phase FOC motors help enourmously with smooth control. Galvo, electrostatic, Henry at UMIST in 1990 built ascanning optical microscope with two 3" loudspeakers and two sweep generators, im feeling inspired.
What could help you to get steeper walls in your etched layer would be to use a microscope optic with a longer focal length so the cone of light that hits your substrate is allot thinner/sharper and doesn't spread out as much towards the top. Also planning on building something like this but instead of galvos I'll use glass cube prisms that displace the beam when rotated. Will adapt your solution of using a microscope lens for the final focusing though, very smart.
Amazing stuff.. if long plastic parts are creeping i can suggest mounting them with a long screw going through the long axis and pressing the part to the extrusion.. maybe it will provide a better stiffness.
The feature size of the defects caused by the aberrations is pretty impressive. I wonder if at some point real photolithography machines will be based on the aberrations we made along the way.
Oh you'll love this: sub-resolution assist features. Not quite the same, but these are features that are added to masks which help compensate for diffraction effects. What's neat is that they are smaller than the minimum feature size that can be made with the mask, but due to diffraction they still "add" to the feature and help fix problems or adjust the final shape. Super neat stuff!
You have done so many cool projects! I am truly impressed. Look forward to the next iteration! How do you not have a million subscribers I do not know.
A source of wobble might be the aluminum extrusion. I worked on a machine that did micron scale automated bonding once. We tried extrusion for the frame first but even with the chonky profiles and structural plates you could bump the side of the thing and wobble it off course.
Great Project. You need definately get rid of the plastic parts, but not only the material is problematic but the design of the part. You want to avoid L shaped parts (and everything "hanging around" at all) beacause of vibratio issues. Also a more compact design with more mass will help with vibrations. Maybe you can get damped metal rods of ebay to replace the aluminium profiles?
Spinning mirrors are always moving so your spot cannot dwell to increase exposure time. Only repeated frames or higher intensity can do that. Repeatable frames will demand that the mirrors rotate synchronously. At some point you will also face reflections from the back glass surface being out of focus and exposing your resist from behind...
Astounding work! What you have achieved is very amazing, almost incredible. I'm looking forward to seeing how you will refine it further. Thanks for sharing!
14:00 - I don't think it is a galvo issue. Something is probably vibrating. Your repeatability test confirms this. If it was a galvo problem, you would see the same problem over and over. I have worked with Cambridge galvos and Thorlabs galvos. See if you can get one of those on E-bay.
Amazingly, my Recommended feed actually proved useful for once by suggesting this video which led me to discover (and subscribe to) your fantastic channel. Cheers!
Could try sitting it on a paver and dense foam for isolation to rule out at least some of the vibration. Surprising such a hodgepodge setup even works, let alone with results that are kind of promising.
This is a great video! I'm new to the channel but I'm SO impressed with the quality and clarity of your videos!!!! Long term subscriber here hopefully!
as far as i understand, the resolution of the scanner can be improved if you use lenses with much greater focal length after it. for example if you use a lens with 2x focal length, then it would convert the same angular deviation into twice linear displacement. it means that the scanner wiuld have to wiggle the beam twice less to achieve the same displacement and hence would have twice less jittering. does it make sense?
Hm, I'm not sure tbh. The scanners are running open loop basically, so it really depends on how accurate and repeatable their "minimum step" is (which probably depends on the resolution of their DACs I guess?). I tried to maximize their dynamic range, because I assumed utilizing the full range would give better resolution than trying to have them perform small moves in a subset of their range. But I'm not really sure to be honest!
@@BreakingTaps hmm, i see how it can go both ways whether you're bottlenecked by dacs or their mechanical inertia. dacs however are perfectly repeatable but their path is not, so i assumed you're limited by inertia.
cool prototype. looks like it could benefit from a solid steel structure and an enclosure so you can temperature control it and eliminate air currents and so forth
No vibration isolation at the moment, although that would definitely help improve reliability (and minimize the feature size). I know that commercial machines are often isolated, but I'm not sure at what point that becomes "required". I.e. is it 10um? 1um? 500nm? Not sure, but it would definitely help!
Awesome project. I don't know much about lasers, but could you use blu-ray laser with its lense from the blue-ray burner/reader to do the same as you did? I think the holes that they burn in to discs are about 130nm wide?
I've been meaning to take the next step in a similar project. Using the LCD for an sla 3-D printer to make pcbs. I've always been curious if I can get the features small and precise enough using a similar method with Optics. Thanks for getting me motivated to go back and experiment with that project/concept some more.
One thing that might give you a major improvement in power is to adjust how you are doing the beam quality enhancing aperature. Running the wide beam through the aperature is blocking a lot of light. If you use two lenses to focus the beam and then return it to parallel, placing the aperature near the focal point might enhance quality while also enabling more light to pass through.
wow incredible work, optics aren't easy! and yeah, the galvo-galvo system seems the weakpoint for now, managing to snag a better pair would make repeatabi;lity much better
Great video, well done. Excellent results based on the components used. Perhaps have a look on eBay or similar for used CD/DVD mastering equipment. You could probably get the table and optics for a good price and it's a lot more sturdy. Most of that equipment is now obsolete.
Cool stuff! Often in DPSS lasers they use a pair of wedge prisms to make the beam with less anisotropism before the rest of the crystals. Perhaps if you such things before your spatial filter, you might get even more a more a Gaussian profile--with a little more power.
Can you use the optical litho to make better optical encoders for the galvos for better precision? Or use it to make MEMS electrostatically driven mirrors to replace the galvos? Maybe optical encoders for servos for the optical train elements to make it auto-calibrating in real time, instead of doing it manually every couple of days? A self-improving machine would be pretty big brain.
I am not familiar with the technologies, but it's a great opportunity to learn about it. And it also makes some of the stuff more accessible instead of it being a 160M EUV box nobody can buy, it's a neat little machine built out of somewhat available parts.... Without a cleanroom! My interest of microbolometers, which could count as mems devices.... So do you think it's possible with the resolution you have right now? Very few great TH-cam channels like this exist. And you will always find them in the comments section on these videos!
Really neat stuff! While I certainly understand how this works on a macro level, I'm not quite sure how some of the different components are interacting together to give the final output. I think I need to re-watch your explanation a few more times. As always with your videos, the topic and application of your ideas to achieve some final outcome is infinitely interesting. Thanks for sharing all of your hard work with us!
Brilliant! A couple of ideas: Use a chunk of machinists' granite mounted on shock mounts for your base. Consider LinuxCNC for g-code control. (lots of options)
What power supply is driving the controller and galvo drives? Some of the wobble and repeatability issues could be from signal noise. In the past to prove or disprove I’ve used a battery to supply power… and get away from a noisy switch mode or ‘other’ noisy supply… also grounding with clean and dirty earths separated is important. Very interesting thanks 🙏🏻
Could you expand the beam before passing it into the pinhole( allowing a larger hole to be used) to get a better quality before focusing it back down and re-collimating it.
Yep! That's a possibility, as well as expanding immediately after the pinhole (letting it diverge further and collimating with a bigger lens). The main reason I didn't do that is because of the galvo: it has relatively small mirrors, so too much expansion before the galvo stage could lead to "clipping" as the mirrors rotate. Expanding after the galvos made that easier.
@@BreakingTaps Ah gotcha. I was thinking that perhaps if expanded before entering the hole it would possibly allow larger hole size and in turn finer control over the final shape and "cleanness" of the beam. I suppose at the end of the day you are dealing with interference being your primary deciding factors for what the sharpness at edge of the beam is like. Better man then me , I love your experiments. I been doing science experiments in my garage since I was a child yet optics and me don't get along. I'm working on interferometer as we speak and precision optics does not jive well with my mad scientist, haphazard style I do so well. I am attempting to see if I can detect faint, ultra high frequency vibrations by vibrating one of the mirrors at a known frequency in hopes it acts in a stroboscopic manner. I am highly intrigued by acoustic skyrmions. Needless to say precision is not the easiest thing when building entirely from scrap parts .
Yeah, I believe you're correct. The beam can also pick up problems from dust particles in the air, so having the spatial filter near the end helps reduce those effects. It ended up in that location mainly due to poor planning and logistics :)
Ok at (0:07) I took that as a maskless method, sorry I see now you mean the resin mask is made with out a photo positive mask, not that you are direct writing the deposited material by using Vapor Deposition with a laser assist so the vapor is not deposited where the laser is striking the surface. Still very forward thinking, love it, and I am guessing if a second laser frequency could be used on a material so one solidifies the material while the other diminishes the permanency of the material it would be even easier to do a direct lithography, like maybe causing it to turn to powder so it would be easy to extract with a static charge attraction. I think though direct write of the material is the way to go, I wish more people were working on this tech like you are, and we all had better way to get together and work on projects! This is the way, Replicator tech will lead to a federation future, while focusing on warp and phasers and photon torpedoes as the first focus leads to an empire dark mirror universe I believe (the tech are all just allagory for working on manufacturing tech first, and waiting to work on transportation, or destructive, tech till we have the most effective and decentralized ownership method. IE. it is micronized so anyone interested can own operate and house it in a garage, on a bench or even in the kitchen or home office, and even better if it is portable in say a trunk to be deployed anywhere,) and by manufacturing I mean the whole package, refining/recycling, power harvesting, assembly, so no supply line of any specialized materials are needed, though more concentrated materials acquisition could be done by mining dump sites for electronics and such, it's still possible if necessary to harvest from the wild like carbon from that lawn you mowed, or feeding in mineral rich rocks you found on a hike. Biggest advantage to it being shrunk and fully replication capable *with the assistance of someone putting the printed parts together, which avoids that whole fear of grey goo* the tech can propagate like a virus, ie if you hobknob with a friend who's house is infected, ie, they have one in their house, with replicator capable tech, you end up with your house infected with it by the fact they know how useful it is and offer to gift you a copy of theirs, which they make using theirs. and this cycle repeats when you find someone lacking one, where you copy yours with yours, and gift them one too, LOL, Before you know it the whole world will be able (even if they don't choose to) participate in a massive world wide opensource process of just about anything, even making killer floating nanobots that are powered by a wireless system at your house and destroying mold spores and viruses keeping your home clean, (and maybe even breaking down the toxins still persisting in our environment like fluorocarbons when they encounter them, as well as solvent evaporated gases like xylene and toulene from spray paint and such LOL)
This is absolutely fantastic work! I can't help but notice you're using 3d printed parts to hold optical components. I'm not sure what plastic you're using, and (I know you already know this) but plastics, especially PLA, have both a stress relaxation and a creep factor which will deform the parts over time. This won't really matter for macroscopic laser projects, but when you're dealing with microns, I would assume both of these variables can throw off alignment really quick. In fact, you could use this setup to measure this over time by firing the laser every hour or so over the course of a day onto a UV photosensitive film and plotting the points. I'm pretty curious what the results would be. Then again, I will admit I have absolutely no idea what I'm talking about when it comes to optics or if any of this drift even matters. The results seem to show none of the above variables matter much. EDIT: You mentioned all this toward the end of the video; I should have really watched the whole thing before commenting 🙃
🚨 *Addendum* 🚨
- "Why not fix the laser and just move the stage under the laser?"
It's a good question! Speed mostly, it's generally a lot slower to draw the pattern with a mechanical stage, particularly if you need a lot of "flood fill" regions. And in theory a galvo can give very small resolution even if the laser spot is relatively large. I.e. you could position a 2 micron line (due to 2um spot size) 200nm away from another line. Depends on the quality of a stage, but precise movements of a large stage are a lot harder than precise rotations of a lightweight mirror, especially considering backlash and such on the stage. But it's a totally viable technique, and I might try it if I can't make the galvo behave. 🙂
- "Why direct-write laser instead of DLP chip?"
No particular reason (my first attempt years ago was with a pico projector actually), I just wanted to try the direct-laser approach. There are some pros/cons to each. With DLP you run into limitations with pixel size quickly, which means you need correspondingly better optics to continue reducing feature size. Direct write laser can "scale" in that aspect a lot cheaper: a good clean beam passed through a 60x objective could theoretically hit sub-micron features. OTOH, you have to deal with issues like the galvo linearity/stability. So different trade offs. You can find commercial devices of both varieties competing in the same space for example :)
Hah, thanks for answering that. What about a stage that is based on one of those flexure designs? That would allow tiny movements.
Thank you for the considered answer! Have you also thought about using a Wicked Lasers LaserCube?
Its blue diode is 1300mW at 445nm, which is within the range (350nm-450nm) specified by Microposit's datasheet.
Is there any way you can see how far off the laser is coming out of the galvo and just use the stage to correct it? You could try to make the lines straighter and maybe even see if for some reason it's repeatably off mark the same amounts in when doing similar things? Kind of like how the Shaper Origin handheld cnc router uses a small but accurate cnc to improve the positioning you do by hand.
Like fgbhrl suggested flexure xyz stages can be very precise, zero backlash, readily characterized and driven by very standard gcode. Any speed lost due to greater inertial mass may be offset by running many parallel beams at once. You could even make mirror images cut at the same time that would register perfectly with their counterparts - which may be useful somehow in the construction of MEMS devices.
Another argument for using a mechanical stage is that your beams (and thus the walls of your resist) could be made to be exclusively perpendicular to the substrate rather than all converging at the microscope lens.
I mean, you already have a sub-micron stepping stage, you just had to make a spatial filter for your laser and half a decent focusing optics to get better results with less effort... Also, is your laser polarized, and was the dichroic designed to work at 45°? Most of the off-the-shelf dichroic are designed to work at normal incidence and suffer big degradation in performance at high angle, especially if the laser is polarized in the wrong direction
I was going to click the like button, then realized I had already clicked! Really nice project.
Thanks Ben! Glad you enjoyed it ♥
@@BreakingTapsI’m a big fan of both of you. You guys do amazing work!
Between the 2 of you I would expect to learn how to like a video twice
Beginner mistake, no worries, it´ll go away... By "Breaking Taps" u click "like" always before starting the video, everyone knows... ;-)
I see a colab in the future
Nice project Zach! I've got a remark: given the resolution of your patterns, your resist layer thickness is at least several microns. Generally, you don't need that kind of thickness if you want to do subsequent etching. Using a resist layer thickness of less than 300nm will improve your image definition dramatically, because fully exposing a thick layer of photoresist in a very short time all the way to the bottom is very difficult. This is because of the optical density at the laser wavelength and the fact that photobleaching of the photosensitive component isn't instantaneous.
That is amazing to see so many wizards in one comment section!
Thanks for the tips, that's great to know! I wasn't really sure what thickness to be aiming for, so just chose an arbitrary speed near from the datasheet (3500RPM) and left it constant so there was one less variable to think about. Good news is that it seems pretty consistent, around 1.7-2um each time. I'll try increasing the speed and get a thinner layer for my next tests, thanks!
@@BreakingTaps if 2um is your thickness at 3500rpm, then increasing RPMs is probably not going to give you a significantly thinner layer. Adding a little solvent is a better strategy. Or alternatively you could use a resist like az1505.
Hm yeah, the datasheet maxes out with 500nm @ 7000 RPM. My coater should be able to hit that, I'll give it a shot and see. Good idea about adding some solvent. Will look into AZ1505! I've been wanting to get some SU8 as well, just because it looks very useful for "structural" applications where the resist is left in place.
@@BreakingTaps Be careful with exposed SU8! This stuff is ridiculously hard to remove, nearly had to scrap several fully structured 8" MEMS wafer because someone was curious about my stuff and opened the box outside the yellow light area... (partially my fault because I stored the box outside the litho area, but the stepper was down and all shelfs were full).
The thickness of 150µm wasn't helping this either. Warm acetone or NMP over several hours followed by plasma ashing in a O2/Ar plasma somewhat removed it (I also read that warm Piranha solution makes quick process of the SU8 but would have definitely destroyed my wafer) . At least some devices survived.
I find this channel to be a great compliment to Applied Science. Both channels are doing really complicated things in a home shop, things that you would think would stay in the lab environment.
This guy is doing some crazy work I would never have dreamed could be approached in a DIY setup. The other channel I have seen that blew my mind in this regard is Thought Emporium.
Neato! I'm impressed with the quality you were able to get out of an old 3d printer mirror box. What kind of setup are you hoping to replace it with? some "better" COTS part, or a homebrew with a mirror bolted to a few piezos or something? Hmmm... are piezos too small for this? it looked like your angular range was actually pretty big.
Actually I guess that scaling is a separate question - when you had the "demo raster" running while you walked through the beam path, the lateral displacement of the beam was on the order of mm. How many microns across the surface was that once sent through the rest of the optics and microscope objective and whatnot?
Thanks! I'm not sure what v2 will look like to be honest. The deflections are pretty big (+/- 20degrees? something like that), but that could be changed... I was trying to maximize the full range of the galvos because I figured they would not have much accuracy if trying to make very small deviations. If the a piezo galvo or whatever had very small range, we can tweak the focal distances in the relay system to make it work, probably just with much longer focal distances.
I have a few options that I'm thinking about:
- Getting a better galvo, the "digital" ones designed for etching should be tuned better.
- Some kind of tip/tilt flexure mechanism, actuated by voice coils or high TPI threads or something. I don't _technically_ need all the speed of the galvo, so we can use a slightly slower mechanism too
- a few different more "mechanical" designs (coupling a ballscrew to a rotary mechanism), so we can take advantage of high resolution in the ballscrew mechanism
- A sorta silly idea someone mentioned on Discord which is growing on me: a CoreXY style 3d printer mechanism that "rasters" above the tube lens in the system, replacing the galvo entirely. Similar to how CO2 laser cutters have a traveling mirror, but coupled into a microscope objective. Still mulling that one over.
- Or just admitting defeat and using the wafer stepper for all motions. Would be very slow though.
The "demo raster" was an "X" shape and just about filled the entire field of view (I used it to help align various components). It depends where you look, but on the first lens it travels a few mm, on the second lens it's traveling a centimeter or two. And ultimately the FOV is either 2x2mm (20x objective) or 500x500um (40x objective).
I suggest looking either for proper galvos (like for actually your purpose) or to keep in mind that the mirror surface of your galvos has optical quality. I assume the galvos you used don't actually have the needed surface quality and that this might create the "wobbly" structure of your trial structures.
Just a suggestion from my side - I hope I'm not too late 😅
@@1xBublex1 theoretically if error is repeatable u could calibrate wobble into "control system". But yeah if there is huge variation and bad repeatability is another case.
Wow once again I am blown away. I am fresh out of EE, and watching your videos has got me inspired to work on my own laser scanning microscope.
Do you know if commercial LSMs have enough power to bleach the photoresist?
This is some serious DIY. The fact that you are creating the beginnings of an Integrated Circuit with off the shelf hardware and 3d printed parts is seriously impressive.
Another awesome video and project! I have no doubt that you’ll get it all working flawlessly. Imagine making MEMS devices in a home shop…. Good grief. You and Applied Science are always pushing the limits, and I love it!
We live in interesting times. It's such a pleasure to see highly intelligent people do what they excel at.
Omg... You are unbelievable.... What is your work ethic that you can finish such complex projects....
Powered by project-ADHD 😂 I usually have 3-4 projects going at once, and when I get bored or burnt out I switch to a different one :) This project for example was 90% done in January but I just couldn't make myself finish, so went off to do other things until I got interested again :)
This project wins a Golden Opossum award for showing us a really cool project made with less than stellar components. Can't wait to see V2. (:
You've got to look into green lithography technology. I covered some in my quantum hardware lecture series on QuantumGrad. Basically, egg whites diluted with water can function as a polymer photoresist and even e-beam resist. This means that egg whites can serve as resist material for both micron and nano scale features. Plus, it's non-toxic : D
The stuff you manage to make in a home shop always blows my mind. You’re like a whole other level of Maker.
Absolutely beautiful work, very, very nice! :-)
Yeah, diode laser beam quality is beyond poor. If you want maximum available power and a nice clean beam, have you considered fiber coupling the diode? The beam focused into the end of a nice length of Silica SMA905 fiber, will yield a really nice Gaussian beam profile, plus you can run the fiber wherever you want it...
does the beam need to enter the fiber parallel or can it enter it focused to a point? what angular distribution does is have when it exits?
Thanks Les, means a lot coming from an actual optical and laser expert! :) I haven't really looked into fiber coupling to be honest, and no real reason either, just didn't ocurr to me 🙂 Can you couple in multiple wavelengths to a fiber (so I can also include the red focusing laser)? I assume I'd need a single mode fiber instead of the bigger multi-mode stuff? Thanks for the help! My fiber-fu is pretty weak 😅
@@BreakingTaps I've never done it but I believe so. You'll have to make sure that the fiber is rated for the range of wavelengths used. You also need a lens that optimally couples the free space laser to the single mode fiber. Newport has a good article on this if you search for "Fiber Optic Coupling".
Hey, confocal microscopy guy here! I'm super impressed with what you managed to do diy with a super low budget.
Before blaming galvos, try to see if the unreliability is due to vibrations: they can be absolutely awful, especially in a setup suspended from the table, and with those long 3d printed parts holding heavy optics and metal parts. If you can, try to launch an etching experiment remotely from a pc in another room, consider doing it at night if you are close to a busy road/railway, and if you are not at the ground floor. If the result is much better, it's probably you whole setup wobbling about as you walk, talk, even breathe around it. Better yet, use your extra focusing optical path behind the dichroic to get a microscopy image of a sample on a camera with some decent frame rate (30 fps is enough), if you have vibrations, it will be extremely noticeable.
Also, you can gain a lot of power (if you need it) by focusing the laser on the pinhole, instead of just placing the pinhole in the collimated beam path. As long as the resolution of the lens you use is worse than the size of the pinhole, you should still get a very clean beam out of it, it will just be more finnicky to align.
Thanks for the tips, appreciate getting help from actual experts! Yeah I definitely think vibration is playing a role, although I might have underestimated how much. v2 will probably sit on a granite plate, and I might put some kind of air damper underneath to help with vibrations just to rule it out. That's a clever tip with the camera, will keep that in mind!
And re: laser, I probably explained it poorly. The diode has an integral lens which is focused onto the pinhole, so the efficiency isn't as bad as it seems. But I have the pinhole intentionally misaligned because the aberration from a misaligned pinhole ended up giving better results than full intensity through the too-large-pinhole. That's why the ultimate spot ended up looking so dim. :)
Fantastic ..I worked on optics back in the day .I get surprise about all kinds of new solutions ,that are already available this days .20 year ago something like you have put together will be very ,very expensive ..And only corporations or universities will be able to afford .To see you doing this type of research is a great accomplishment !!
You guys are just awesome. One of you will eventually come up with something that can spit out usable chips within the next 5 years.
You continually make some of the most interesting stuff I’ve ever seen on the internet. Thanks for all of it.
I am everyday fascinated how far we have come. We can do that stuff now AT HOME. Great job!
Nice project! I built the DLP version of this a few years ago, using a UV light engine and a wafer inspection microscope, rigged to step and repeat. Pretty good results at comparable resolution, although with some imperfections on the tiling.
I was attempting DIY PCB lithography at the time this video dropped. What a nice coincidence
It looks like the waves are mostly due to the galvo controller. My light Show laser (unity elite pro3) was wavy similar to yours until I aligned it using the potentiometers on controller board. Basically projecting a grid test pattern with pangolin quickshow software and adjusted the controllers until the corners are as close to square as possible. I'm fairly new to pro lasers but these adjustments solved my wavy problems
Pretty cool. I’ve been in semiconductors for over 20 years, servicing mask aligners. 😆
i struggle with a ikea shoe shelf and this man just diys himslef some lithography im truly stoopid
Excellent explanation of the optics between the galvos and microscope objective!
the pinnacle of scien for general public explained in a very clear way. yes this videos will start a revolution!
Amazing you built a small copy of one of the most complicated machines on earth. 👍👏. ASML should hire you.
You'll love the video that's scheduled for next week! Building a newer and better photolithography machine :)
@BreakingTaps I can't wait 🙂 maby one day you can build layers and increase the number of transistors in short a true integrated circuit with 3d scaffolding. I recently came across this channel, and the few videos I have seen are extremely impressive. I look forward to supporting this channel any way I can. I'll be in suspense until your next video. Thank you 👍
Took me weeks to align the mirrors on my K40 crapbox, i am in awe of a setup like this, yes different worlds, i know
Way fun and interesting! It is super nice to experience new ideas and principals from a source that elucidates these concepts so understandingly in both general idea and detail. Seriously, well done.
I love your honesty and comments on plastic parrs..good work!
You beat me to my dream project. Absolutely stellar job, so great to see that hobbyists can do this!
Another incredible video, as usual. Blows my mind what "home makers" are capable of, these days. Keep up the great work, looking forward to seeing more in the future!
I still cannot believe that you don't have several million subscribers, it's a crime against humanity!
♥
This is the type and level of diy we need to future proof agents SHTF! The more that know this stuff the better off and safer we are.
Great explanation with animations at 9:30. I'd be interested to see a version with Huygen's spheres overlayed onto the video
yep, that was amazing
huygens spheres are problematic with singular rays that can't actually exist. as in, they only exist because the beam is much thicker than the wavelength but its wave structure is inconvenient to visualize and it also causes inevitable diversion over distance.
homemade slicon cpu when? you have tried silicon doping, you have the laser machine....
also your channel is awesome
i guess i now have a project to follow on this channel for the forseable years to come
Really nicely done. I use SU-8 spinned on a Si wafer in combination with a 365nm Led and a pattern printed on a transparancy (outsourced to a specialized printing company cost around €20 for an A4). Placed the transparancy on the wafer with a thick piece of UV tranparant glass. Expose and develop. Very high aspect ratio's possible with a spatial resolution down to 3-5 micrometers.
Dr Nick, can you share the company that you used to print the masks?
@@arguetav ProArt BV in Groningen, The Netherlands. Ask for film with high density in black/white. Transparant for UV and black silver blocks UV. Resolution in micrometers. Just give them a call and discuss your needs.
You're fast becoming one of my favourite youtubers
Criminally cool. The combo of the work your doing now with the etching is incredible.
Thanks to this video my decision is final. I am going to learn RISC-V.
really well explained for something as magic as optics to my smooth brain
Well done mate. It just goes to show how complicated this process is. How Intel and AMD do the things they do blows my mind.
Great project, thank you! I'm thankful there are folks like you around. If society ever collapses, you're the kind of guy who will help build everything back. (Sorry if I have a depressing opinion of our world and where it's going, but you at least give me hope.)
Have you seen Robin Renzetti on TH-cam? He mostly does very precise machining, stuff like machine spindles. He also machines his own surface plates and measures them for flatness with an autocollimator. To do this, he made custom mirror mounts, and I think you'd like his kinematic mounts. He made a custom differential screw to get better resolution when adjusting the mirrors. Maybe something there would help you out?
Very nice videos, keep them up!
I love Robin! That man has so much knowledge packed into his head it's amazing. Not sure I saw the custom mirror mounts though, will go dig through his videos to find it. Thanks for the tip!
Utterly impressive that this can be made as a DIY system.
Fascinating project. Like that it is 3Dp parts ebay/amazon parts. Very cool. Also, happy to see you are wearing the 'favorite' ball cap.
Just listened to your within tolerance episode and I’m stoked to watch your backlog of videos again! Such good content.
in a past I replace galvos(rotation will be always limited by angle step) with XY positioning movement system. Similar to XY CNC light router/plasma cutter etc. The laser beam come to X mirror which you can make X movement and then to Y mirror. You need a bigger lens after XY positioning system, but resolution can go up to 100 nm. Have you tried ?
Amazing work, subscribed. Reminds me of taking image stacks through the microscope, Driven by steppers it was move, wait for vibration to stop, open shutter, wait for vibration to stop,flash led light, close shutter. Had to move it from an attic to a cellar due to vibrations. The frame wasn't sturdy but with the right setup it worked very well, these vibrations are always there however big the machine. three phase FOC motors help enourmously with smooth control. Galvo, electrostatic, Henry at UMIST in 1990 built ascanning optical microscope with two 3" loudspeakers and two sweep generators, im feeling inspired.
Dude, you are changing my life over here....
Thanks I had selected the same project for pbysics and now with your contribution I can do it
Looking forward to watching this evolve. Great work!
What could help you to get steeper walls in your etched layer would be to use a microscope optic with a longer focal length so the cone of light that hits your substrate is allot thinner/sharper and doesn't spread out as much towards the top.
Also planning on building something like this but instead of galvos I'll use glass cube prisms that displace the beam when rotated.
Will adapt your solution of using a microscope lens for the final focusing though, very smart.
Amazing stuff.. if long plastic parts are creeping i can suggest mounting them with a long screw going through the long axis and pressing the part to the extrusion.. maybe it will provide a better stiffness.
The feature size of the defects caused by the aberrations is pretty impressive. I wonder if at some point real photolithography machines will be based on the aberrations we made along the way.
Oh you'll love this: sub-resolution assist features. Not quite the same, but these are features that are added to masks which help compensate for diffraction effects. What's neat is that they are smaller than the minimum feature size that can be made with the mask, but due to diffraction they still "add" to the feature and help fix problems or adjust the final shape. Super neat stuff!
You have done so many cool projects! I am truly impressed. Look forward to the next iteration! How do you not have a million subscribers I do not know.
A source of wobble might be the aluminum extrusion. I worked on a machine that did micron scale automated bonding once. We tried extrusion for the frame first but even with the chonky profiles and structural plates you could bump the side of the thing and wobble it off course.
Definitely possible! Between the extrusion and the generally unstable / cantilevered design, I wouldn't be surprised!
Great Project. You need definately get rid of the plastic parts, but not only the material is problematic but the design of the part. You want to avoid L shaped parts (and everything "hanging around" at all) beacause of vibratio issues. Also a more compact design with more mass will help with vibrations. Maybe you can get damped metal rods of ebay to replace the aluminium profiles?
Spinning mirrors are always moving so your spot cannot dwell to increase exposure time. Only repeated frames or higher intensity can do that. Repeatable frames will demand that the mirrors rotate synchronously. At some point you will also face reflections from the back glass surface being out of focus and exposing your resist from behind...
The only thing I really understand is lasers can instantly blind me so I'm glad people make videos like this so I can still enjoy it
Another great video! I'm always excited when I've seen you've posted a new one. Keep 'um coming!
How about a Risley prism instead of a galvo? It might make for a much more robust and stable assembly.
Oh! Interesting! I wasn't aware of these devices, looks super cool. Will do some more reading, cheers for the tip!
Astounding work! What you have achieved is very amazing, almost incredible. I'm looking forward to seeing how you will refine it further. Thanks for sharing!
14:00 - I don't think it is a galvo issue. Something is probably vibrating. Your repeatability test confirms this. If it was a galvo problem, you would see the same problem over and over. I have worked with Cambridge galvos and Thorlabs galvos. See if you can get one of those on E-bay.
Amazingly, my Recommended feed actually proved useful for once by suggesting this video which led me to discover (and subscribe to) your fantastic channel. Cheers!
Could try sitting it on a paver and dense foam for isolation to rule out at least some of the vibration. Surprising such a hodgepodge setup even works, let alone with results that are kind of promising.
This is a great video! I'm new to the channel but I'm SO impressed with the quality and clarity of your videos!!!! Long term subscriber here hopefully!
as far as i understand, the resolution of the scanner can be improved if you use lenses with much greater focal length after it. for example if you use a lens with 2x focal length, then it would convert the same angular deviation into twice linear displacement. it means that the scanner wiuld have to wiggle the beam twice less to achieve the same displacement and hence would have twice less jittering. does it make sense?
Hm, I'm not sure tbh. The scanners are running open loop basically, so it really depends on how accurate and repeatable their "minimum step" is (which probably depends on the resolution of their DACs I guess?). I tried to maximize their dynamic range, because I assumed utilizing the full range would give better resolution than trying to have them perform small moves in a subset of their range. But I'm not really sure to be honest!
@@BreakingTaps hmm, i see how it can go both ways whether you're bottlenecked by dacs or their mechanical inertia. dacs however are perfectly repeatable but their path is not, so i assumed you're limited by inertia.
cool prototype. looks like it could benefit from a solid steel structure and an enclosure so you can temperature control it and eliminate air currents and so forth
What effect does sound vibrations etc have on the system? Is it isolated from outside vibrations so that they don’t interfere with the precision
No vibration isolation at the moment, although that would definitely help improve reliability (and minimize the feature size). I know that commercial machines are often isolated, but I'm not sure at what point that becomes "required". I.e. is it 10um? 1um? 500nm? Not sure, but it would definitely help!
@@BreakingTaps Don't need anything fancy. Some tire inner-tubes under an optical bench will knock out everything above a 2-3 Hertz.
Awesome project. I don't know much about lasers, but could you use blu-ray laser with its lense from the blue-ray burner/reader to do the same as you did? I think the holes that they burn in to discs are about 130nm wide?
I've been meaning to take the next step in a similar project. Using the LCD for an sla 3-D printer to make pcbs. I've always been curious if I can get the features small and precise enough using a similar method with Optics.
Thanks for getting me motivated to go back and experiment with that project/concept some more.
I see your uploads and drop everything to watch at 1x!
One thing that might give you a major improvement in power is to adjust how you are doing the beam quality enhancing aperature. Running the wide beam through the aperature is blocking a lot of light. If you use two lenses to focus the beam and then return it to parallel, placing the aperature near the focal point might enhance quality while also enabling more light to pass through.
Amazing you got such good results with 3d printed parts!
I was pretty shocked to be honest, much better than I expected!
Man, this is TH-cam gold, amazing!
this man! like the quality is just bullshit good- always outstanding
wow incredible work, optics aren't easy! and yeah, the galvo-galvo system seems the weakpoint for now, managing to snag a better pair would make repeatabi;lity much better
Probebly also a stiffer mount made from metal to house them in maby the bodys twist a bit in the plastic due to the acceleration
18:45 Could you put a light sensor array where you put your work, step down the power (as not to burn out the sensor) and use that auto-calibrate?
Great video, well done. Excellent results based on the components used. Perhaps have a look on eBay or similar for used CD/DVD mastering equipment. You could probably get the table and optics for a good price and it's a lot more sturdy. Most of that equipment is now obsolete.
This was great! The thought of materials science to the nanometer...at home!
Your channel blows my mind
Excellent video!! Thank you so much for sharing.
Cool stuff!
Often in DPSS lasers they use a pair of wedge prisms to make the beam with less anisotropism before the rest of the crystals. Perhaps if you such things before your spatial filter, you might get even more a more a Gaussian profile--with a little more power.
Can you use the optical litho to make better optical encoders for the galvos for better precision? Or use it to make MEMS electrostatically driven mirrors to replace the galvos? Maybe optical encoders for servos for the optical train elements to make it auto-calibrating in real time, instead of doing it manually every couple of days? A self-improving machine would be pretty big brain.
“Evolutionary design” is how I’m going to describe every “winged it” project from now on.
Wonderful! What made you choose Galvos instead of a DLP chip like Sam Zeloof uses?
I am not familiar with the technologies, but it's a great opportunity to learn about it. And it also makes some of the stuff more accessible instead of it being a 160M EUV box nobody can buy, it's a neat little machine built out of somewhat available parts.... Without a cleanroom! My interest of microbolometers, which could count as mems devices.... So do you think it's possible with the resolution you have right now?
Very few great TH-cam channels like this exist. And you will always find them in the comments section on these videos!
Really neat stuff! While I certainly understand how this works on a macro level, I'm not quite sure how some of the different components are interacting together to give the final output. I think I need to re-watch your explanation a few more times. As always with your videos, the topic and application of your ideas to achieve some final outcome is infinitely interesting. Thanks for sharing all of your hard work with us!
Brilliant! A couple of ideas: Use a chunk of machinists' granite mounted on shock mounts for your base. Consider LinuxCNC for g-code control. (lots of options)
What power supply is driving the controller and galvo drives? Some of the wobble and repeatability issues could be from signal noise. In the past to prove or disprove I’ve used a battery to supply power… and get away from a noisy switch mode or ‘other’ noisy supply… also grounding with clean and dirty earths separated is important. Very interesting thanks 🙏🏻
Mirrors can be moved linearly rather than rotated. This will also give a raster
Could you expand the beam before passing it into the pinhole( allowing a larger hole to be used) to get a better quality before focusing it back down and re-collimating it.
Yep! That's a possibility, as well as expanding immediately after the pinhole (letting it diverge further and collimating with a bigger lens). The main reason I didn't do that is because of the galvo: it has relatively small mirrors, so too much expansion before the galvo stage could lead to "clipping" as the mirrors rotate. Expanding after the galvos made that easier.
@@BreakingTaps Ah gotcha. I was thinking that perhaps if expanded before entering the hole it would possibly allow larger hole size and in turn finer control over the final shape and "cleanness" of the beam. I suppose at the end of the day you are dealing with interference being your primary deciding factors for what the sharpness at edge of the beam is like.
Better man then me , I love your experiments. I been doing science experiments in my garage since I was a child yet optics and me don't get along. I'm working on interferometer as we speak and precision optics does not jive well with my mad scientist, haphazard style I do so well. I am attempting to see if I can detect faint, ultra high frequency vibrations by vibrating one of the mirrors at a known frequency in hopes it acts in a stroboscopic manner. I am highly intrigued by acoustic skyrmions. Needless to say precision is not the easiest thing when building entirely from scrap parts .
Brilliant video! I hope to see further iteration on this project!
It looks very cool!
Maybe if you use thin wire to suspend the mirrors and a magnetic or electro-actuator, you'll get a much better result.
isn't it better to put the pinhole as far down the light path as possible (right before the scanner) to remove more nonparaxial rays?
Yeah, I believe you're correct. The beam can also pick up problems from dust particles in the air, so having the spatial filter near the end helps reduce those effects. It ended up in that location mainly due to poor planning and logistics :)
@@BreakingTaps wait is that actual dust? I thought you're using a fog machine in every single video that goes well with your cool lighting
Ok at (0:07) I took that as a maskless method, sorry I see now you mean the resin mask is made with out a photo positive mask, not that you are direct writing the deposited material by using Vapor Deposition with a laser assist so the vapor is not deposited where the laser is striking the surface. Still very forward thinking, love it, and I am guessing if a second laser frequency could be used on a material so one solidifies the material while the other diminishes the permanency of the material it would be even easier to do a direct lithography, like maybe causing it to turn to powder so it would be easy to extract with a static charge attraction.
I think though direct write of the material is the way to go, I wish more people were working on this tech like you are, and we all had better way to get together and work on projects! This is the way,
Replicator tech will lead to a federation future, while focusing on warp and phasers and photon torpedoes as the first focus leads to an empire dark mirror universe I believe (the tech are all just allagory for working on manufacturing tech first, and waiting to work on transportation, or destructive, tech till we have the most effective and decentralized ownership method. IE. it is micronized so anyone interested can own operate and house it in a garage, on a bench or even in the kitchen or home office, and even better if it is portable in say a trunk to be deployed anywhere,)
and by manufacturing I mean the whole package, refining/recycling, power harvesting, assembly, so no supply line of any specialized materials are needed, though more concentrated materials acquisition could be done by mining dump sites for electronics and such, it's still possible if necessary to harvest from the wild like carbon from that lawn you mowed, or feeding in mineral rich rocks you found on a hike. Biggest advantage to it being shrunk and fully replication capable *with the assistance of someone putting the printed parts together, which avoids that whole fear of grey goo* the tech can propagate like a virus, ie if you hobknob with a friend who's house is infected, ie, they have one in their house, with replicator capable tech, you end up with your house infected with it by the fact they know how useful it is and offer to gift you a copy of theirs, which they make using theirs. and this cycle repeats when you find someone lacking one, where you copy yours with yours, and gift them one too, LOL, Before you know it the whole world will be able (even if they don't choose to) participate in a massive world wide opensource process of just about anything, even making killer floating nanobots that are powered by a wireless system at your house and destroying mold spores and viruses keeping your home clean, (and maybe even breaking down the toxins still persisting in our environment like fluorocarbons when they encounter them, as well as solvent evaporated gases like xylene and toulene from spray paint and such LOL)
Could you try exposure by passing the light beam through a small transparency picture of the desired etch, instead of using a galvo?
Years ago I had a set of piezoelectric galvos for very fine deflection.
This is absolutely fantastic work!
I can't help but notice you're using 3d printed parts to hold optical components. I'm not sure what plastic you're using, and (I know you already know this) but plastics, especially PLA, have both a stress relaxation and a creep factor which will deform the parts over time.
This won't really matter for macroscopic laser projects, but when you're dealing with microns, I would assume both of these variables can throw off alignment really quick.
In fact, you could use this setup to measure this over time by firing the laser every hour or so over the course of a day onto a UV photosensitive film and plotting the points. I'm pretty curious what the results would be.
Then again, I will admit I have absolutely no idea what I'm talking about when it comes to optics or if any of this drift even matters. The results seem to show none of the above variables matter much.
EDIT: You mentioned all this toward the end of the video; I should have really watched the whole thing before commenting 🙃
100% agree! Working on v2 which will feature a lot more metal components :)