PROCESS AND DESIGN PARAMETERS TO MINIMIZE TOMBSTONING DURING SURFACE MOUNT REFLOW
Author: R.K. Sharma Company: University of Colorado Date Published: 4/28/1997
Surface Mount International
Abstract: Tombstoning is one of the undesirable defects that contributes to poor soldering yield during reflow of a passive SMT component. Tombstoning occurs when one end of the component becomes detached from solder paste and the component ends up standing on the other end after reflow process. To answer these questions, a fundamental under-standing of this phenomenon is needed to arrive at desired process parameters that would prevent tombstoning. In this paper, we present a parametric study of various factors affecting tombstoning. First, a preliminary model developed earlier for prediction of tombstoning effect is modified to enhance its capability to model real-life tombstoning and non-tombstoning cases. A response variable for evaluating tombstoning performance of various parametric configurations is defined and an experiment is designed to study the effect of variation of both design and process parameters on tombstoning. Based on the sensitivity analysis, recommendations are made for avoiding tombstoning.