Analysis of solder mask roughness and stencil shape influence on void formation in solder joints

Abstract Voids inside solder joints are empty spaces negatively affecting the mechanical, thermal, and electrical properties of joint. This article deals with this problematics using two novel approaches to reduce voids’ occurrence. The first approach is change roughness mask influence flux spreading around pad. second deposition same volume paste pads a modified, thicker stencil smaller apertures. experiments were performed for pastes containing SAC305 alloy types fluxes (ROL0/ROL1). Solder inspected by X-ray imaging, shots subsequently processed image analysis. For determination area pad during reflow process, tested boards scanned confocal digital microscope. results showed that more aggressive caused less voiding in terms average voids covering soldering Analysis samples prepared modified stencils much lower proportion than standard stencil. Furthermore, revealed selection type significantly influenced formation within case unmodified deposition. On other hand, when used sample preparation, had no further impact on voiding. Therefore, modifying can be pointed out as preferable effective way.