Ashers (Technics PEII)
These two parallel plate plasma etching systems are generally used to clean organic residue off of semiconductor wafers (ashing), etch organic films, or etch Si3N4 films. The systems are both equipped with O2 for organic removal. In addition to organic removal, the oxygen plasma is also useful for changing the surface polarity of organic films to facilitate wetting of water-based surface etchants. This is very important for wet-etch processing through small, high aspect ratio photoresist holes or lines. One system also has CF4/O2 88% / 12% for etching Si3N4. These systems are operated manually and no sign-up is required.
- Gases used: CF4 / O2 (88%/12%) and O2
- ~ 10mT ultimate chamber pressure
- 100 kHz directly coupled excitation source
- Sample size: pieces to 6” wafers
- Gas flow and power control
- Typical process conditions:
- Ashing: O2 300mT, 100W power, 30 sec.
- Si3N4 Etching: CF4/O2 300mT, 100W, ~ 150 nm / min. etch rate