2003 年 6 巻 5 号 p. 433-438
We have implemented a company-wide effort to progressively reduce the use of lead and eventually eliminate this environmental pollutant from its products. As part of this effort, a new lead-free solder, which consists of tin, zinc, and aluminum, has been developed and also offers superior productivity and joint reliability. The new lead-free solder has a melting point equivalent to that of a tin-lead eutectic solder, and enables devices to be packaged at a lower temperature than the increasingly popular tin-silver-copper solder. Thus, the new lead-free solder accelerates the elimination of lead from products. We have already used PC boards containing the new lead-free solder in some products, and plans to extend its use to other products. This paper describes the characteristics of the new lead-free solder and the results of a study on its practical use.