Singe - 30 minutes at 150C (unless your wafers came out of a furnace
or deposition system and are coated with resist within one hour).
- Coat the entire wafer with PIQ Coupler-3
- Spin on the headway at 3000 rpm's for 120 to 180 seconds (look for
rainbow to fade)
- Bake in Blue M Oven for 60 minute ramp from 20C to 350C; 30 minutes
at 350C; 60 minute ramp back to 20C.
- Polyimide may be spun up only on the headway coater. (There are chemical
incompatibility problems for the other coaters.) Spin at slow rpm's
and slowly pour PIQ L-100 Polyimide onto wafer (starting at center and working
- After wafer is covered, spin at 3000 rpm's for 30 seconds to get
a 2um thick film (for thicker film, slow spin speed and increas time).
- Optional: During the spin, hold a Q-Tip by the wafer to catch
the "strings" of polyimide so they don't hang on and wrap around
the bottom. Some users do this, but I recommend skipping it and keeping the
door closed during the spin step.
- Poke out any bubbles in the polyimide.
- Place on a hot plate at 105C for 1 minute.
- Bake in Blue M Oven 30 minute ramp from 20C to150C; 30 minutes at
150C; 15 minute ramp to 200C; 30 minutes at 200C; 40 minute ramp to 350C;
60 minutes at 350C; 60 minute ramp to 50C
- You could use AZ4620 to pattern the polyimide and etch in a drytek etcher.
Some users pattern 2000A of Aluminum and use that as a mask to etch the polyimide
in the drytek.
- Drytek2 Etch: Power 700W; Pressure 100 mTorr; O2 Flow 100 sccm. Etch Rate
Stanford Nanofabrication Facility