A new polyimide film for VLSI and its electrical characterization

Multilevel structures consisting of alternating metal and dielectric layers are necessary to achieve interconnection in high density or VLSI (very large scale integration) circuits using either MOS or bipolar technology. Polyimide is one of the excellent high temperature heat-resistant polymers in organic materials and has good planarization capability and electrical insulating properties. In this work, following the synthesis of DAPDS (4,4'-bis (3-aminophenoxy)diphenyl sulfone), by nucleophilic aromatic substitution of 4,4'-dichlorodiphenyl sulfone with m-aminophenol, DAPDS/pyromellitic dianhydride based soluble and processable fully imidized polyimide was synthesized successfully by using solution imidization technique. Using this specific polyimide, a metal-polyimide-silicon MIS (metal polyimide silicon) structure was manufactured. Electrical properties of the MIS capacitance have been examined. The planarizing and patterning characteristics and electrical characteristics such as current vs. voltage, breakdown field strength, permittivity and capacitance vs. voltage for quasi-static and high frequency measurements are discussed. The results are compared with conventional dielectric films used in integrated circuit fabrication.