Patent ID: 6564987
Filing Date: 2003-05-20
Classification: B23K,H01L,H05K,Y02P

Abstract:
A method of evaluating configuration of solder external terminals of a BGA-type tape-based semiconductor device mounted on a mounting board such that said external terminals are joined to lands provided on said mounting board, comprising the steps of:a) deriving total solder volume of said solder external terminal by summing volumes of solder paste filled in an opening of a tape substrate, a solder ball and solder paste provided on said land; b) calculating parameters characterizing a spherical solder drop based on said total solder volume and a radius of said land; c) deriving a level where a diameter of a circle on a horizontal plane traversing said spherical solder drop is equal to a diameter of said opening of the tape substrate and thus deriving a distance between said level and the highest point of the spherical solder drop; d) deriving a ratio of a thickness of said tape substrate to said distance; and e) evaluating said configuration of solder external terminals based on said ratio.