Helen Holder

Adhesion strength of solder joints to Alloy 42 component leads

Low adhesion strength of Sn-Pb solder joints to Alloy 42, a widely used material for electronic component lead-frame, is a well known but little studied problem in the electronic packaging and assembly industry. In this study, the adhesion strength of two lead-frame materials, Cu and Alloy 42, soldered with 63Sn-37Pb were compared in push-off tests. It was found that the adhesion to Alloy 42 is weaker than to Cu. Higher reflow temperature and longer reflow time strengthen the adhesion, but the effect is not significant in the temperature and time ranges which are practical for electronic assembly. The failure analysis indicates that the solder joints on Cu failed within the solder, while the solder joints on Alloy 42 failed by a clean separation between solder and the lead. Similarly, poor adhesion to Alloy 42 was also observed with 43Pb-43Sn-14Bi, and the problem was more severe. The push-off strength of the 43Pb-43Sn-14Bi joints on Alloy 42 leads was only 50% of 63Sn-37Pb on Cu leads.

3D Monolithic Metal Orifice Plate for SERS Application: A Showcase of Low Cost MEMS Packaging

Electroplating is a low cost process where metal ionsin a solution are reduced by an applied electric field onto aconductive substrate. This process has been studied extensively, but is still critical for modern technology and R&D. In the HPinkjet printing business, electroplating is primarily used in themanufacturing the orifice plate (OP) for integrated print-headproducts. To extend the OP functionality, a novel cost-effectivethree-dimensional (3D) OP has been developed to addressnumerous micro-electro-mechanical systems (MEMS) applications, including surface enhanced Raman spectroscopy(SERS).

Acceptance testing of BGA ball alloys

The industry has seen the development of a wide range of new Pb-free BGA ball alloys. A significant element of uncertainty regarding these new alloys is the lack of defined data requirements for alloy acceptance. This paper describes recent efforts at Hewlett-Packard to develop Pb-free solder alloy testing requirements. To facilitate the standardization of alloy testing, the required tests are divided into three major areas. • Material properties • Solder joint reliability • Impact to manufacturing processes This paper presents the approach to assess the risk of using new Pb-free BGA ball alloys on printed circuit assemblies.