Novel Photosensitive Solder Resist with High Reliability for Semiconductor Package(II)

摘要

The increasing demands for small, thin, and high performance electronic equipment raise the specification on higher density pattern, narrow pad pitch and fine line and space of the semiconductor package substrates. Accordingly the outermost layers of solder resists are needed to have 1) excellent Highly Accelerated Stress Test(HAST) resistance performance with thinner film, 2) high crack resistance at the Thermal Shock Test(TST), and 3) high resolution for fine pattern. For HAST resistance, we reduced chlorine ion and improve anti-hydrolysis properties in solder resist. This new technology significantly improves ion migration resistance resulting in a higher HAST reliability even with a thinner solder resist film. For crack resistance, a simulation has been designed to analyze the mechanism of cracking as well as a target of physical properties of the solder resist possessing superior crack resistance. High crack resistance was successfully achieved at the TST using the solder resist with elastomer forming nano-phased separation and filler surface treatment. For high resolution, we optimized exposure wavelength and the refractive index of the material and successfully demonstrated good resolution in accordance with the design size.