Statistical process control applied to automated dispense of silver filled epoxy for commercial millimeter wave multi chip module

This paper presents the results of continuous improvement from: Designed Experiments, Viscosity measurements, Statistical Process Control, documented operating procedures, and operator training and certification; on the automated epoxy dispense process. This capability enables the company; M/A-COM, to produce the first volume low cost 28 GHz Commercial Millimeter Wave Multi Chip Module Receiver. The Millimeter Wave Multi Chip Module Receiver uses GaAs Phempts measuring 12 by 10 mil length and width by 5 mil thick. This small discrete device required the development of a process for a ten mil diameter silver paste epoxy dot: repeatable, in production, and in volume. Statistically Designed Experiments were used to identify and set the most important process parameters. Viscosity measurements were made which characterized the silver filled epoxy paste. The ASTM methods for measuring viscosity of adhesives were modified to identify the material's sensitivity to shear. A unique Statistical Process Control method was implemented to establish process control over a material which has proven to change flow behavior during processing through an auger type positive displacement pump. The key to the success of this project has been properly train operators.