Using Polyimide Tape To Mask Against Reactive-Ion Etching

Polyimide tape (Kapton™ or equivalent) has been found to be effective as a material for masking selected areas of a semi- conductor wafer that is about to be processed in a reactive-ion etching (RIE) apparatus. The conventional etch- resistant masking materials for protecting selected areas against etching are photoresists and oxides. These materials are patterned into masks by standard photolithographic techniques. The use of polyimide tape is an inexpensive option that provides additional flexibility for increasing the protection of some areas and for implementing lastminute design changes without having to incur the high cost of making optical masks for photolithography.