Sn-Ag-Cu-X eutectic alloy leadless welding materials for electronic elements

Abstract

A lead-free eutectic Sn-Ag-Cu-P (or Ge) alloy solder for microelectronic industry contains Ag (3.2-4 wt.%), Cu (0.5-0.8), P (or Ge) (0.001-0.2), and Sn (rest). It has high antioxidizing power in liquid state.

Description

technical field [0001] The invention relates to a lead-free solder alloy in the welding field, in particular to a Sn-Ag-Cu-X quaternary eutectic alloy lead-free electronic solder. Background technique [0002] Soldering is a very old and practical technology. It mainly adopts the alloy system based on the Sn-Pb eutectic composition (Sn63%-Pb37%, both are weight percentages, the same below). The eutectic temperature of this lead-tin alloy is It has a temperature of 183°C, has good mechanical properties and process properties, has a long history of use, and has accumulated a lot of production and practical application experience. At the same time, the cost of raw materials is low and the resources are extensive, so it has been widely used in industry. The main problem with this alloy system is that the solder alloy contains more than 35% lead, which has been proven by numerous studies to be a toxic metal. With the increase of electronic waste, after a large number of waste el...

AI Technical Summary

Problems solved by technology

[0009] In order to overcome the problem in the prior art that the surface of the liquid alloy is easily oxidized under atmospheric conditions, the purpose of the present invention is to provide a method that can improve the oxidation resistance of the liquid surface of the Sn-Ag-Cu solder alloy and obtain better alloy performance. Sn-Ag-Cu-X eutectic alloy lead-free electronic solder