| abstract |
The low modulus polyimide adhesive compositions of the presentninvention contain a low modulus polyimidosiloxane polymer, anthermosetting substantially-non-halogenated epoxy (optionally includingnan epoxy catalyst), a plasticizer, an insoluble halogen-free flame-retardantnfiller, and optionally an adhesion promoter. The adhesive can be appliednupon (or incorporated into) flexible circuits using a relatively low laminationntemperature, generally no higher than 200, 190, 180, 175, 170, 165, 160,n155, or 150°C. The adhesive is generally resistant to unwanted curl evennin cases where the adhesive polyimide and the base film polyimide have ancoefficient of linear thermal expansions (measured between 50°C andn250°C) that differ by more than 10, 15, 20 25, or 30 ppm/°C. |