10 um laser point for microlithography

[martintw]

Hello,

I would need microlithography system. So I was thinking of using my cnc machine and mount a laser to it. The problem is that I dont know what laser to chose. I will be using positiv 20 photoresist wich cures at 405 nm wavelength and needs exposure strength of 100 mJ/cm² for 10s at 8 um film thickness. I would like to have 10 um laser point. Is something like this even achievable ? What components do I need to use ?

Thanks for help.

Best regards Martin.

 

[diachi]

Yes, it's possible. Actually, less than 10um should be possible at 405nm. A 100mW 405nm laser module with a driver capable of analogue modulation (So that you can turn down the power if you need to) would be suitable. I calculated the spot size using a 50mm focal length lens which focused a 5mm, collimated beam, not with the built in focusing lens you see on lots of modules. I don't have the numbers to calculate that. With a 5mm input beam and a 50mm FL lens that gets you down to around 10 microns, actually should be a little smaller. With 100mW that's 3312.28W/mm^2 or 331.2W/cm^2 - well above the power you need (10mW/cm^2). If I'm calculating correctly that give you a speed of ~30mm/second with 100mW output power and a 6.2um beam. That's if I'm calculating correctly... someone else may want to work it out too.

See this for some ideas:

Laser PCB Exposer Built From CD-ROM Drives | Hackaday