Thermally stable photoimaging composition
AssigneeInternational Business Machines Corporation
InventorsVoya Rista Markovich, Ashit Arvind Mehta, Eugene Roman Skarvinko, David Wei Wang
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Abstract
A thermally stable photoimaging composition and a method of using the same, especially on circuit boards as a solder mask is provided. The composition includes a polymerizable resin or resin system, a cationic photoinitiator, a solvent, and an optically transparent ceramic filler. Preferably, the composition has a coefficient of thermal expansion of about 28-40 ppm/.degree.C., which closely matches the coefficient of thermal expansion of the solder used on the circuit board components.
Claims23
A photo-patternable solder mask thermally stable at 360.degree. C., consisting essentially of a photosensitive cationic photoinitiator admixed with a cationic polymerizable epoxy resin, a solvent and a filler consisting essentially of an optically transparent silicon dioxide filler transparent to wavelength of 310 to 400 nanometers, said composition having a coefficient of thermal expansion of 28-40 ppm/.degree.C., wherein said solder mask is both an encapsulant and a dielectric.
Dependencies are inferred from the claim text.