Patent ID: 6220501
Filing Date: 2001-04-24
Classification: B23K,C22C,H05K

Abstract:
A method of joining a pair of metallic members together, comprising the steps of:preparing said pair of metallic members in coated form, wherein one of the metallic members is coated with a first undercoat composed of tin and zinc and the other of the metallic members is coated with a second undercoat composed of tin and zinc;contacting the metallic members with each other either through a flux or in a reducing atmosphere, while heating the metallic members to melt at least one of the first undercoat and the second undercoat; andsolidifying the molten undercoat to join the metallic members,wherein the ratio of zinc in the first undercoat is represented by x (% by weight), the ratio of zinc in the second undercoat is represented by y (% by weight), and the ratio, x, and the ratio, y, are values such as satisfy the following formulas:1.ltoreq.x.ltoreq.20, 3.ltoreq.y.ltoreq.13, 3.ltoreq.(x+y)/2.ltoreq.13and the relationship that the composition of the mixture of the first undercoat and the second undercoat comes to or is closer to the Sn--Zn eutectic composition than each composition of the first undercoat and the second undercoat,wherein the content of other metals than zinc and tin which is contained in each of the first undercoat and the second undercoat is 0.1% by weight or less.