Abstract
With the sophistication and miniaturization of electronic devices, printed wiring boards are progressing to ever higher densities. In the field of solder resist (SR), the miniaturization of the wiring with higher density, there is an increasing demand to improve thermal shock resistance. In an effort to increase thermal shock durability, we have devised a design that reduces the mobility of the polymer terminal of the cured film. A SR which contains a polyurethane binder having terminal carboxyl groups has been found to improve the thermal shock durability.
