Singe - 30 minutes at 150°C (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 minutes ramp from 20°C to 350°C; 30 minutes at 350°C; 60 minute ramp back to 20°C.
- 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 out)
- After wafer is covered, spin at 3000 rpm's for 30 seconds to get a 2µm thick film (for thicker film, slow spin speed and increase 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 105°C for 1 minute.
- Bake in Blue M Oven 30 minute ramp from 20°C to150°C; 30 minutes at 150°C; 15 minute ramp to 200°C; 30 minutes at 200°C; 40 minute ramp to 350°C; 60 minutes at 350°C; 60 minute ramp to 50°C
- 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 400A/minute.