Patent ID: 7628308
Filing Date: 2009-12-08
Classification: B23K,H05K

Abstract:
1. A soldering method comprising: preparing a solder bath having an initial composition prior to initial soldering using the solder bath and containing a first nonzero concentration of an oxidation suppressing element; performing a first soldering operation for a period of a plurality of days using the solder bath while replenishing the solder bath with a first replenishment solder alloy having the same composition as the initial composition of the solder bath to maintain the surface level of molten solder in the solder bath, the concentration of the oxidation suppressing element in the solder bath reaching a second concentration at the end of the period; determining the average rate of decrease of the oxidation suppressing element in the solder bath during the first soldering operation over the period; and performing a second soldering operation using the solder bath after the first soldering operation and starting when the concentration of the oxidation suppressing element in the solder bath is at the second concentration while replenishing the solder bath to maintain the surface level of molten solder in the solder bath with a second replenishment solder alloy having a third concentration of the oxidation suppressing element which is higher than the first concentration, the third concentration having a value such that the rate of supply of the oxidation suppressing element in the second replenishment solder alloy to the solder bath in the second soldering operation is greater than or equal to the determined average rate of decrease of the oxidation suppressing element in the solder bath during the first soldering operation.