Protonation Effects On PPQ Polymer During HF Lift-Off Process Used In Multichip Module Fabrication.

The reactions between PPQ and several acidic solutions have been studied. Protonation reactions have been evidenced using U.V.- Visible spectroscopy. PPQ revealed three different states concerning these completely reversible reactions. Each state exhibits a specific colour: Pale yellow (as deposited PPQ), and gold yellow and purple red for, respectively, the first and the second protonation states. Using IR spectroscopy, it has been shown that the protons are fixed at the nitrogen sites of the polymer. A possible degradation of the PPQ related to the protonation reactions is also studied, and thus technological solutions are proposed.