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
Positive/Negative/Image Reversal Chemical Stability Thermal Stability Optical Properties Solvent The Resin The Photo Active Compound

The photo active compound of AZ® and TI positive and mage reversal resists belong to the group of diazonaphtoquinone-(DNQ-)sulfonates. Added to the resin, the DNQ-sulfonates act as inhibitor decreasing the alkaline solubility of the resist by 1-2 orders of magnitude. During exposure with matched wavelengths (typically 320..440 cm), the DNQ-sulfonate converts into indene carboxylic acid by releasing nitrogen (N2) and consuming a H2O molecule. Hereby, the alkaline solubility increases by 3-4 orders of magnitude which ist 1-2 orders of magnitude higher as compared to novolak without DNQ-sulfonate at all.

The AZ® 2000 negative resist family does not work as explained above. Hereby, the exposure induces the crosslinking of the resin which is completed by a subsequent post exposure bake.
Weiterführendes Dokument (pdf) Optical Absorption Coefficients of selected Photoresists  The Photoreaction
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