STS Pegasus 4/Processes

This page lists the processes supported by the LNF for the STS Pegasus 4. The same recipes are available on the STS Pegasus 6, although due to hardware differences, the etch rates and uniformity will be slightly different.

For all process questions, fill out the process request form and create a helpdesk ticket.

Bosch process recipes

• STS Pegasus 4/Processes/LNF Recipe 1

  This recipe is designed for etching relatively small (1-100 μm) features with a vertical, smooth sidewall and minimal undercut. Etch rates depend on feature size and vary from 2-6 μm/min.

• STS Pegasus 4/Processes/LNF Recipe 2

  This recipe is designed for deep and through wafer etching of small (1-500 μm) features on masks with a low exposed area (<20%). Undercut and scalloping is larger than LNF Recipe 1, but etch rates are higher (4-13 μm/min).

• STS Pegasus 4/Processes/LNF Recipe 3

  This recipe is designed for deep and through wafer etching particularly on masks with a large exposed area (>20%). Undercut and scalloping is larger than LNF Recipe 1, but etch rates are higher (4-16 μm/min).

• STS Pegasus 4/Processes/LNF Recipe 4

  This highly specialized recipe is designed for high aspect ratio etching of small features (1-10 μm) with very low open area (<10%). The etch produces the most vertical sidewall with the least undercut, particularly at the top of the trench.

• STS Pegasus 4/Processes/LNF Switched Poly

  This recipe is designed for shallow etches and thin-film poly- and amorphous silicon etching. It uses a switched process similar to the standard deep silicon etches.

Other silicon etch recipes

• STS Pegasus 4/Processes/LNF Unswitched Poly

  This recipe is for shallow etches and thin-film poly- and amorphous silicon etching. It uses a single-step mixed gas process to minimize undercut, but is not very accurate.

• STS Pegasus 4/Processes/LNF Si Thinning 1

  This recipe is intended for isotropic thinning of Si wafers for device release. It does not have high uniformity, but has good selectivity to other materials.

• STS Pegasus 4/Processes/LNF Si Thinning 2

  This recipe is intended for isotropic thinning of Si wafers for device release. It does not have high uniformity.

Supplemental recipes

• STS Pegasus 4/Processes/LNF Ar Descum

  This recipe uses an Ar plasma to anisotropically and indiscriminately remove a thin layer of any material on the surface of the sample. It is intended as a combination of photoresist descum and native oxide removal prior to Si etching. This recipe is already included in all of the standard recipes.

  Maximum etch time is 2 min.

• STS Pegasus 4/Processes/LNF O2 Descum

  This recipe is uses an O₂ plasma to isotropically remove polymers. It is intended as a photoresist descum prior to etching, although it may oxidize the exposed surface. The Ar descum is better suited for normal circumstances. This recipe may also be used for photoresist mask stripping post process, although there are other systems at the LNF with better performance for this process.

  Maximum etch time is 5 min.

• STS Pegasus 4/Processes/LNF Oxynitride LF

  This recipe is for etching oxide and nitride. It is primarily useful for native oxide removal prior to a deep Si etch, but can also be used for definition of an oxide mask for etching.

  This recipe is not officially maintained by the LNF. There are significantly better tools for etching oxide and nitride that should be considered before using this recipe. Please create a helpdesk ticket or email info@lnf.umich.edu if you have further questions.