A novel measurement technique for stencil printed solder paste

Abstract

The printing process is the most critical step in surface mount assembly. To control and monitor printing, complex instrumentation is available for measuring the print consistency. This paper describes a novel robust method, which introduces critical variables defining print quality. Conventional measurement methods include only the volume and average height of solder paste. The limitations of using just these parameters are discussed and a new method is introduced. In our novel approach, the matrix is levelled first to take account of any tilt in the plane of the substrate surface. Then pseudo‐virtual object parameters are calculated. Major attributes of the proposed measurement method is its insensitivity to both the specific location of the printed deposit and the location of a specific defect. This algorithm, coupled with variables defined in the analysis package, delivers a new and flexible approach to the printed media.