Etching method for silver-copper solder

Abstract

The invention relates to an etching method for silver-copper solder. The etching method comprises the following steps of (1) alkaline oil removal, specifically, a brazed semi-finished product outer shell is put into an alkaline oil removal solution to be cleaned up; (2) water washing, specifically, the brazed semi-finished product outer shell is washed by tap water firstly and then washed by usingdeionized water; (3) pickling, specifically, the water-washed outer shell is put into a pickling liquid to be washed; (4) drying, specifically, a high-temperature blast drying box is used for high-temperature drying the water-washed outer shell; (5) etching, specifically, the outer shell is placed in an etching solution; and (6) final processing, specifically, the outer shell is taken out after etching is finished, the step (2) water washing and the step (4) drying are repeated. The etching method has the advantages that (1) the silver-copper solder is etched without any corrosion damage, thecoverage of outer shell brazing appearance, size, solder and subsequent plating reliability are high; (2) the etching process is slowed down, and the etching time range is increased; (3) environmental pollution is relieved; (4) the etching method is low in cost, simple and easy to operate; and (5) the problem of silver displacement of radio frequency power device outer shells is solved, and the effect is remarkable.

Description

technical field [0001] The invention relates to an etching method of silver-copper solder, which belongs to the technical field of surface treatment. Through the method, the silver-copper solder can be selectively removed from all positions of the whole. This method is especially useful for obtaining the desired shell brazing shape, size, solder coverage and subsequent plating reliability. In addition, this method is especially critical as a pre-treatment for products with "silver migration" requirements . Background technique [0002] Silver-based solder is the longest and most widely used type of solder in solder. Especially the Ag-Cu eutectic (Ag72-Cu28) solder is currently the most widely used solder in the soldering process of electronic packaging devices. It has a low melting point, no crystallization interval, good fluidity, and the thermal conductivity and electrical conductivity of the formed weld Good performance, so in the manufacture of electronic packaging com...

AI Technical Summary

Problems solved by technology

[0003] 1) The brazing appearance of the shell does not meet the requirements, and the size is poor;

[0004] 2) The number of holes in the solder layer and the inclusion of impurities increase, and these impurities cannot be cleaned up during subsequent plating, resulting in an increase in the proportion of peeling and blistering after plating;

[0005] 3) The coating cannot fully wrap the solder well, resulting in the problem of silver migration;

[0006] 4) It may have a certain impact on other reliability of the device

However, there is currently no good way to etch the silver-copper solder specifically or preferentially so that the solder is removed from all parts of the product