Atomic force microscopy, laser ablation, and etching with toxic chemicals: it sounds like [Zachary Tong] Playing in the lab again, this time he found Method for manufacturing microlens array as a result.
Like many of the best projects, [Zach]The journey into micro-manufacturing began with a happy accident. This happened when he was working on metal activated chemical etching (MACE), which used precious metal catalysts to selectively engrave high aspect ratio features in silicon. After blasting the silver-plated silicon wafer with a laser, he noticed that the ablation pits after etching were very smooth and uniform. This led him to put forward several hypotheses about what was happening, all of which he could test.
The experiment itself is fun, but what’s really cool is [Zach] Realize that the smooth hemispherical pits in silicon can be used as molds for micro-convex lens arrays. He was able to deposit a small amount of transparent silicone resin into the mold by spin coating and (eventually) transfer the microlens array onto a glass slide. These lenses are very small—hundreds of lenses are only a few hundred square microns—and they are very well shaped. Of course, there is always room for improvement, but for initial attempts based on accidental discovery, we call it a victory. As for how good these lenses are, your guess is as good as ours. But new processes like this often find a useful method, and the fact that this is from a home laboratory does not change this fact.
We found this kind of micro-manufacturing very attractive. Whether it’s making OLED displays, micro-machining glass with plasma, or rolling our own semiconductors, we can’t get enough of these things.