Photoresist Processing Trouble-Shooting Etchants and Solvents
Photoresists Ancillaries Storage/Handling/Ageing Substrate Pre-Treatment and Coating Baking Steps Exposure Development Coating and Lift-off Etching and Stripping
Substrate Pre-Treatment Spincoating Spraycoating Dip Coating
In case of clean substrates (virgin wafers/wafer with fresh thermal oxide), baking at 120░C-140░C for some minutes is sufficient for the desorption of H2O. Adhesion promotion is recommended applying a pretreatment with HMDS (only from the gaseous phase on the heated substrate!) or TI PRIME. The coating should be performed directly after cooling down of the substrates in order to avoid re-adsorption of water.

Substrates contaminated with particles/organic impurities can be prepared with a two-stage substrate cleaning for the improvement of the resist wetting and adhesion: Acetone removes organic impurities, a subsequent rinse in isopropyl removes the contaminated acetone thus avoiding striations. The solvent NMP allows the removal of organic impurities which are hardly soluble in acetone. In case of a more significant contamination (organic/metals), or, respectively, before contamination-critical high-temperature steps, Si-wafer require a so-called piranha-etch with subsequent RCA-cleaning.

After SiO2-etching with HF (e.g. HF-dip), the resist adhesion strongly depends on the completeness of SiO2-removal: With SiO2 completely removed, the now hydrogen-passivated Si-surface reveals a very good adhesion, while remaining oxide shows a very bad and not reproducible adhesion, which can be restored only at high temperatures (700░C oven).

Metals such as aluminium or titanium generally reveal a very good resist adhesion, while the wetting and adhesion on noble metals (silver, gold) often is worse.
e-Mail Anfrage Product request: TI PRIME Adhesion Promoter e-Mail Anfrage Product request: NMP e-Mail Anfrage Technical request: RCA-cleaning
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Photoresists (positive, negative, image reversal, thin and thick resists, spray resists, protective coating ...)
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Etchants (acids and the ready-to-use etching mixtures aluminium etch, chromium etch, gold etch und silicon etch)
Solvents (acetone, isopropyl alcohol, MEK ... in VLSI and ULSI quality)