DEVELOPMENT OF A LOW PERMITTIVITY FLUORINATED COPOLYMER FOR INTERLEVEL DIELECTRIC APPLICATIONS

Technology for future integrated circuits will require advances in all facets of materials and processing. Low dielectric constant materials will require advances in electrical, thermal, and mechanical behavior before process integration can occur, The dielectric constant must be lower than that of amorphous silicon dioxide and possess the right pr operties for integration with future metallurgies such as copper. Seve ral organic thermoset resins that were predicted to possess the necess ary characteristics have been synthesized and studied. A thermoset cop olymer of 1,3,5-tris(2-allyloxy-hexafluoro-2-propyl) benzene with poly methylhydrosiloxane oligomers was identified as a material worthy of f urther development. Thermal gravimetric analysis indicates relative st ability up to 350 degrees C for short periods of time (30-60 min). The complex permittivity was measured up to 40 GHz and was found to be 2. 40 with a loss tangent of 0.008. Compatibility with copper multilevel processing was determined by a secondary ion mass spectroscopy analysi s. Copper ion migration did not occur. The processability of the diele ctric resins was investigated to address the integration issues associ ated with the fabrication process. (C) 1997 American Vacuum Society.