Evaluating the Printability of Solder Paste From Paste Roll Characteristics

摘要

The printability of the solder paste, is critical to product yield in a SMT (Surface Mount Technology) line. Both the material and the process must be controlled to minimize variations in solder paste printability and reduce soldering defects. In this letter we describe a newly developed print tester that measures characteristics. of the squeegee/drum-stencil interaction to monitor. the printability of solder paste. The device includes an optoelectronic monitoring system- to detect the paste roll velocity, allows precise adjustment of the printing [parameters and imposes a continuous squeezing action on the solder paste. We use the, measurements of roll velocity as function of time and distance to propose a new measurement standard, named "print life", which offers a quantitative and cost-effective evaluation-of the printability of solder paste.