Chapter 8 - Polyimides for Microelectronics and Tribology Applications

Abstract

This chapter focuses on Polyimides used for microelectronics and tribology applications. Polyimides (PIs) are a class of high-performance polymers existing both as thermoplastic and thermosets, which are characterized by the repeating imide. They are synthesized from the condensation polymerization of an aromatic dianhydride with an aromatic diamine. The reaction involves the nucleophilic attack of the amino group on the carbonyl carbon of the dianhydride group followed by the opening of the anhydride ring to form amic acid group. The formation of polyimides proceeds in two steps: formation of an intermediate polyamic acid and ring closure by eliminating water molecules to yield high-molecular-weight polyimide. The backbone of polyimide is made up of alternating units of dianhydride and diamines, the polyimides are abbreviated as dianhydride-diamine. Polyimide, derived from pyromellitic dianhydride (PMDA), and oxydianiline (ODA), is known as “PMDA-ODA,” whereas those derived from benzophenone tetracarboxylic dianhydride, and Terphenyl tetracarboxylic dianhydride are known as “BTDA and TPDA,” respectively. Various PI materials are commercially available from different base resin manufacturers.