Specific Process Knowledge/Etch/Etching of Polymer

Polymer dry etching

Upgrading the silicon etch capability at Danchip with the DRIE-Pegasus has pushed our old ASE (Advanced Silicon Etcher) out of the line so that it now only serves as backup silicon dry etcher. We have therefore decided that the ASE must be converted to a polymer etcher instead. Hence, it will join the plasma asher and to some extend the RIE's where polymer etching is allowed. In RIE1 it is only for removing photo resist before or after a RIE etch if the plasma asher cannot be used for some reason. On RIE2 you can get allowance for some other polymer etching but you have to ask first.

• Etch of Photo Resist using RIE

Etching of polymers on the ASE

SPTS has provided some recipes for polymer etching on the ASE. They have NOT been tested yet (As of August 2011) and we are therefore very interested in learning whatever experiences you have. Please contact Jonas. The recipes are located in the root folder. Please copy them to your own folder and modify them there for your own purposes as you would with any other recipe.

The polymer recipes

Name	Materials		Process parameters								Comments
	Mask	Etched	O2	CO2	SF6	He/Ar	Pressure	Temp	Coil	Platen
novolac	Oxide hard mask	polyimide/PMMA	0	50	0	0	4	0oC	600	150	This will etch PMGI, PI, & standard resists. We've never tried it for PMMA, but it should work

e.g Novolac polymer, oxide hard mask: 50 CO2, 4 mT, 0 degrees C, 600W, 150W. This will etch PMGI, PI, & standard resists. We've never tried it for PMMA, but it should work

An alternative chemistry for standard resists,PI, PMMA is 20 O2, 20 He, 3 mT, 600W, 150 W, 10 degrees C. This will give higher etch rates & better selectivities, but slightly more bowed profiles

       BCB:                    7 SF6, 43 O2, 4 mT,  800W, 150W, 20 degrees C.  this is also a good start point for PDMS / Ormocer-type Si/ inorganic-containing polymers.  The SF6 / O2 ratio will depend on the composition of the polymer.