Evelyn:

Both are similar with respect to chemistry. Typically an oxygen plasma is
used for both with the biggest difference being ashing requires a very high
removal rate and descum is slower and more controlled to help with a uniform
removal of resist typically at the resist/substrate interface. Ashing us
usually done with high temperature to the substrate to increase removal rate
and descum is better accomplished at a lower temperature <40 degrees C. Also
less either RF or Microwave power is used on the source to slow down the
rate. A good descum rate is around 500 angstroms/minute while a good ash
rate is 1-2 microns/ minute.

Bob Henderson

----- Original Message -----
From: "Evelyn B" 
To: "General MEMS discussion" ; "Evelyn Benabe"

Sent: Thursday, January 22, 2009 8:02 AM
Subject: [mems-talk] Descum and Ashing Diff

> Can you someone please tell me what is the difference between descum and
> ashing?
>
> EVELYN BENABE