Au-Sn SOLDER POWDER AND PASTE FOR SOLDER CONTAINING THE POWDER

• Main Authors: IWATA KOTARO, HIGAMI AKIHIRO
• Format: Patent
• Language: English; Japanese
• Published: 08.06.2017
• Subjects: ALLOYS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; CASTING; CHEMISTRY; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; FERROUS OR NON-FERROUS ALLOYS; MACHINE TOOLS; MAKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; PERFORMING OPERATIONS; POWDER METALLURGY; PRINTED CIRCUITS; SOLDERING OR UNSOLDERING; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WELDING; WORKING BY LASER BEAM; WORKING METALLIC POWDER

PROBLEM TO BE SOLVED: To provide a solder powder which does not oxidize a powder surface and does not cause secular deterioration of paste after being prepared into the paste, and to provide the paste for solder containing Au-Sn solder powder which is excellent in melting property and wetting property upon reflow.SOLUTION: An Au-Sn solder powder is composed of a center core and a coating layer with which the center core is coated, in which the center core comprises Sn or an intermetallic compound AuSn, when the center core comprises Sn, the coating layer comprises Au, when the center core comprises an intermetallic compound AuSn, the coating layer comprises an intermetallic compound AuSn, when the center core comprises Sn, a middle layer composed of two layers of a first middle layer and a second middle layer is interposed between the center core and the coating layer, the first middle layer comprises an intermetallic compound AuSn, the second middle layer comprises an intermetallic compound AuSn, a proportion of the middle layer occupied in one particle of the solder powder is 45 mass% or more and is less than 100 mass% and a content proportion of Sn is 15.0 to 25.0 mass% with respect to the total amount 100 mass% of the solder powder.SELECTED DRAWING: Figure 1 【課題】粉末表面が酸化せずペーストに調製した後でペーストが経時劣化しないはんだ粉末、及びリフロー時の溶融性と濡れ性に優れたＡｕ−Ｓｎはんだ粉末を含むはんだ用ペーストを提供する。【解決手段】中心核と中心核を被覆する被覆層で構成されるＡｕ−Ｓｎはんだ粉末において、中心核がＳｎ又は金属間化合物ＡｕＳｎからなり、中心核がＳｎからなるとき、被覆層はＡｕからなり、中心核が金属間化合物ＡｕＳｎからなるとき、被覆層は金属間化合物Ａｕ5Ｓｎからなり、中心核がＳｎからなるとき、中心核と被覆層の間に、第１中間層と第２中間層の２層で構成される中間層が介在し、第１中間層は金属間化合物ＡｕＳｎ、第２中間層は金属間化合物Ａｕ5Ｓｎからなり、はんだ粉末の一粒子中に占める中間層の割合が４５質量％以上１００質量％未満であり、はんだ粉末の全体量１００質量％に対し、Ｓｎの含有割合が１５．０〜２５．０質量％であることを特徴とする。【選択図】図１