CHARACTERISTICS OF ORGANIC FILM DEPOSITED BY PLASMA-ENHANCED CVD USING BCB RESIN

摘要

Plasma-enhanced chemical-vapor deposition (CVD) at temperatures below 250℃ using a liquid source of benzocyclobutene (BCB) resin, dissolved in mesitylene, was investigated to deposit thin BCB film of less than 1-μm thickness with accurate thickness control. CVD film with a thickness of 0.3 μm was successfully deposited at 150℃ using 150 W on a 3-inch wafer with a thickness uniformity of 3%. The CVD film retains the advantages of spin-coated film, such as low dielectric constant, high breakdown voltage, low stress, and low moisture absorption. However, the CVD film can be treated by reactive ion etching using only O_2 gas, which cannot etch spin-coated film because of its Si content. From Fourier transform infrared spectroscopy, Auger electron spectroscopy, and pyrolysis gas chromatography/mass spectroscopy, CVD film has almost no methyl-siloxane, which exists in spin-coated film. The step-coverage of the CVD film is conformal and considered advantageous for use in ultrafine structures.