Differences

This shows you the differences between two versions of the page.

--- mla150 [2021/07/13 21:59]
dteal
+++ mla150 [2021/11/30 17:36] (current)
dteal
@@ Line 15: / Line 15: @@
 | 16 Jun 2021 | Daniel | Heidelberg field service engineer tuned up tool. Now: optical autofocus is best at focus -2, pneumatic autofocus is best at focus +4, top side alignment accuracy within 300nm (spec 500nm), bottom side accuracy within 850nm (spec 1um), and required exposure dose should be 50% to 75% higher than previous recorded values. |
 | 12 Jul 2021 | Daniel | Spun standard 2um MiR701 on picotrack after a primeoven recipe 2 on a fused silica wafer. Using pneumatic autofocus, a dose of 210mJ/cm2 and focus +4 exposed the pattern fairly well, +/- 0.2um, but did not do full dosage test. |
+| 10 Oct 2021 | Daniel | Ran exposure test for AZ P4620. Use primeoven recipe 2 for HMDS, then spin 12um AZ P4620 with standard picotrack recipe (optionally no TEBR). Ideal exposure was at 800mJ/cm2, 0 defocus. Higher exposures will make large nitrogen bubbles in the resist (this is probably a result of heating, so it could be solved by exposing more slowly or in multiple shorter exposures, but that isn't an option on mla150); lower exposures will not completely develop. Can run through standard picotrack2 develop recipe twice for better effect (not all exposed PR is completely removed the first time; thick resists are tricky). Any further descum or hardbake will reflow the photoresist; I don't have a way around this yet. |
+| 11 Oct 2021 | Daniel | Exposed AZ P4620 with < 20% ambient humidity in NanoLab (there's a humidity meter display on the wall by svgcoat3). The resist failed to develop! Apparently DNQ-based photoresists need water in the resist, delivered via ambient humidity, to expose properly. This is why the resist is supposed to sit for ~30 minutes in ambient air after spinning before exposure. Solution: wait for a time when NanoLab humidity is sufficiently high (e.g., > 40% is probably good) (it's not actively controlled because it's almost always > 40% anyway), or put wafer into humidity box near zeiss-sem. |

Berkeley Autonomous Microsystems Lab

User Tools

Site Tools

Differences

Page Tools