Novel Approach Solder Paste Printing on 90μm Pitch Application

Smaller components in system in a package (SiP) addresses the needs of miniaturization by using cutting edge technology in advanced packaging applications, which involves integration of passive components, flip-chips, integrated devices, etc. Increasing demands for a reduced footprint requires solder paste technology to constantly reinvent SAC305 solder paste. The Type-7 (<11μm) powders were processed by Welco™ technology and formulated into water soluble (WS) solder paste that provided consistent print volume and prints for stencil opening (≥55μm) and pitch (≥90μm). Even though solder pastes can achieve the 90um pitch capability, other factors significantly contribute to printing defects such as substrate quality, printing parameter, printing accessory and equipment process capability limitation. The present paper discusses critical challenges contributing to printing defects in the 90μm pitch stencil printing application and provides a detailed explanation and control guidelines.