Lead is a toxic heavy metal. Excessive absorption of lead in the human body can cause poisoning. Low intake of lead may affect human intelligence, nervous system and reproductive system. The global electronic assembly industry consumes about 60,000 tons per year. Solder, and it is increasing year by year, the industrial residue containing lead salt is seriously polluting the environment, so reducing the use of lead has become the focus of attention around the world. Many large companies in Europe and Japan are accelerating the development of lead-free alternative alloys. And has planned to gradually reduce the use of lead in electronic product assembly in 2002. Completely eliminated by 2004. (Traditional solder composition 63Sn/37Pb, lead is widely used in the current electronic assembly industry)