Ion chromatography as a process control tool in semiconductor leadframe manufacturing

摘要

Semiconductor packaging places great demands on the cleanliness of the environment to which the surfaces of electronic component materials are exposed. Leadframes, the building Nocks of many of these packages (Fig. 1), encompass precious metal electroplating as an essential step in the manufacturing process, thereby presenting a notable challenge in this regard. Ultra-trace levels of surface contaminants such as electroplating salts can adversely effect wirebonding and solderability. Surface analytical techniques (e.g. Scanning Auger Spectroscopy, AES) have been used for failure-mode analysis to detect surface contamination. Surface analysis is limited, however, by the expense of the equipment, difficulty of the analysis and microscopic size of the area examined. Alternatively, ion chromatography is an excellent tool for the detection of water-soluble surface contaminants. Nanogram quantities of ions per linear foot of "reel-to-reel" plated parts can be analyzed with relative ease for a fraction of the cost of surface analytical techniques. The technique also provides the identity of the surface contaminants which is quite useful for determining the source of contamination.