Solderability Characteristics of Palladium , Palladium Nickel , Hard and Soft
Palladium and palladium alloys are the only serious ahematives to gold as an "electronic finish". In the past, the major impetus for such a substitution has been economic; however, today palladium's technological advantages are generally recognized. This is especially true in the connector markets where the material properties (e.g. hardness, ductility, thermal stability, etc.) of palladium are in many instances superior to hard gold. Recent advances in plating technologies coupled with a m r e thorough understanding of the materials properties have expanded the use of electroplated palladium and palladium alloys in the PCB, semiconductor and optoelectronic packaging markets. To assess the suitability for such applications, the wire bondability and solderability of these finishes need to be investigated.
SURFACE FINISH FOR ELECTRONIC PACKAGING WITH LEAD-FREE SOLDERS
Current trends in the preservation of our environment are forcing the electronic industry to seriously consider lead-free solders. In a variety of options such as Tin alloys with Indium, Bismuth, Silver, Zinc and others, the issues of their functional performance involves their solderability to the substrate. Clearly, good fatigue characteristics, tensile strength, ductility, adequate melting temperature and acceptable material cost may not be utilized if the solder requires aggressive fluxes or its "spreadability" is inadequate. Thus, a lead-free solder applied on a substrate engineered for good solderability becomes a viable packaging tool. We have tested a variety of multilayer finishes developed at AT&T for applications on PWBs and MCMs and established that they can be successfully utilized in lead-free soldering processes. In this paper, we discuss experimental details and solderability results with some of the viable lead-free solders.
Metallurgical Process Engineering
The "material of choice" - steel.- Uprising of China's steel industry.- Process manufacturing industry and process engineering.- Engineering science in steel manufacturing process.- Analysis and integration of metallurgical manufacturing process.- Multi-dimensional mass flow control for metallurgical manufacturing process.- Time factors in steel manufacturing process.-Operating dynamics in the production process of steel plant.- Structure and mode of steel plant.- Steel plant and environment.