A Comparison Study Focused on the use of Electroplated Zinc Material as an Alternative to Electroplated Copper Material

摘要

Manufacturers of electronic components continually search for more cost effective solutions to the escalating price of raw materials, innovative alternatives for base metals are being explored. One of the proposed base materials being considered is zinc and zinc alloys. As this abstract is being written the cost of copper is approximately three to four times the cost of zinc. Limitations for direct replacement include differences in certain physical properties such as tensile strength, hardness, and toughness. Some of these properties can be replicated by increasing material thickness or adding alloying elements to overcome limitations. This paper will focus on other limitations found in zinc such as contact resistance, solderability, and surface corrosion (white rust). By applying certain electroplated coatings to the zinc base material, many of these surface related restrictions can be overcome. This paper will compare electroplated zinc coupons to similarly electroplated copper coupons. These samples will be exposed to both thermal and thermal/humidity test conditions in an effort to replicate aging effects. Once aged, the test coupons will be tested for solderability and contact resistance. Cross-sectional analysis will be utilized in an effort to analyze the effects of temperature on the migration of the base material. Several types and thicknesses of barrier layers will be utilized to develop a system that is resistant to the effects of zinc migration.