New estimation method of wetting and surface tension by measuringarea of spreading solder in flux atmosphere based on ellipseapproximation of Sessile drop configurations

摘要

A method for analyzing the wetting behavior which allowsestimation of the movement path and final form of molten solder has beendeveloped. This method is based on an energy analysis which considersthe total balance, as opposed to the local balance contact angle methodused conventionally for analyzing wetting behavior. In this report, themethod is applied to the spreading of solder balls, and the effects ofphysical properties on wetting behavior are examined. It is found thatthe physical property which influences the wetting behavior the most isthe ratio of wetting tension to surface tension, and this ratio issuitable as a parameter for analyzing soldering defects such as solderbridges