Semiconductor optical lithography.
https://diqn32j8nouaz.cloudfront.net...y_fullsize.jpg
Previously:
https://www.homemadetools.net/forum/...068#post187650
https://www.homemadetools.net/forum/...982#post207110
https://www.homemadetools.net/forum/...278#post192213
https://www.homemadetools.net/forum/...718#post186372
