Specific Process Knowledge/Etch/Etching of Polymer

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Etching of Polymer

Stripping of polymer is often done by wet chemistry in a solvent that dissolves the given polymer. If wet chemistry cannot be used or a more controlled etch of the polymer is needed a plasma system is used instead. Plasma ashers are designed for removing polymers in primarily oxygen plasmas. It you need a more directional etch with a masking material RIE2 or ASE can be used.

Polymer Etch by ASE

Plasma asher 1

Plasma asher 2

Comparison of methods for polymer etching

	ASE	Plasma asher 1	Plasma asher 2	Wet Polymer stripping
General description	The ASE was originally a dedicated deep Si etcher, but with the arrival of the Pegasus it has now been opened for polymer etching.	The plasma asher is good for dry stripping polymers. It can also be used for descum and pattering of polymers.	The plasma asher is good for dry stripping polymers. It can also be used for descum and pattering of polymers. This plasma asher is for Si wafers without metals.	Wet polymer etching is used for stripping a resist/polymer when it is no longer needed. E.g. removing resist masks.
Etch direction	Process dependent: Isotropic to anisotropic (vertical to sample surface)	Isotropic	Isotropic	Dissolves the polymer
Possible etch reactants	Oxygen plasma Oxygen plasma mixed with SF₆ CF₄ Ar	Oxygen plasma Oxygen plasma mixed with N₂ CF₄	Oxygen plasma Oxygen plasma mixed with N₂	The different solvents available at Nanolab, such as Acetone 1165 Remover
Substrate size	Samples smaller than 100 mm wafers must be glued to a 100 mm wafer or placed in a reces on a 100 mm wafer. #1 100 mm wafer #1 150 mm wafer (only when system is set up for 150 mm wafers)	Several small samples #25 50 mm wafers #25 100 mm wafers #25 150 mm wafer	Several small samples #25 50 mm wafers #25 100 mm wafers #25 150 mm wafers	Any sample # and size that can go into the beaker used.
Allowed materials	Silicon wafers with layers of Silicon oxide or silicon (oxy)nitride Photoresist/e-beam resist PolySilicon Aluminium Polymers (list?) Quartz/fused silica wafers Metals (no Pb and Te) max 5% wafer coverage Polymer wafers?	Si, SiO2, Si3N4 Glass Metals (no Pb or Te) Resists, polymers	Si, SiO2, Si3N4 Glass Resists, polymers	Any material that may go into the beaker used.