The application of polyimides as insulators in multilevel interconnect systems is receiving considerable attention for very-large-scale integration (VLSI) production. For a tight control of wet chemical pattern formation, as well as for the ultimate adhesion in the finished device, a fundamental understanding of polymidesubstrate interactions is important.

We have examined the effects of molecular weight, chemical composition, and interphase structure on the dissolution behavior of polyimides on silicon substrates. The dissolution rate of partly cured polyimides was found to depend strongly on the above parameters, and showed distinct regions of behavior. The overall-etching characteristics of the materials examined were dominated by surface adhesive interactions.

A method was developed to quantify the chemical adhesion during etching of polyimides. A phenomenological model of the dissolution behavior will be presented and its implications for VLSI processing will be discussed.