Title :
Flex on cap-solder paste bumping
Author_Institution :
Flip Chip Technol., Phoenix, AZ, USA
Abstract :
Soldered flip chips require the formation of a solder bump on the semiconductor device. Traditional solder deposition methods of evaporation and plating have limitations both from a cost structure as well as in capability to meet product requirements. Presented in this paper are the capabilities and reliability results of the FOC (Flex on Cap) solder paste bumping process developed by Delco Electronics and practised by flip chip technologies. This paper describes the fine pitch capabilities, solder alloys, bump height uniformity, alloy control and reliability data for the FOC process. The solder paste process permits cost effective bumping of low alpha solders either W/Pb or Pb free alloys. The importance of the UBM (Under Bump Metalization) for reliable eutectic Pb/Sn and other high Sn content solders that are important for the DCA (Direct Chip Attach) market is shown. The system level cost savings of having all the necessary solder present on the IC, eliminating the deposition of solder on the board, are given
Keywords :
circuit reliability; fine-pitch technology; flip-chip devices; microassembling; printed circuit manufacture; soldering; Delco Electronics; Pb-Sn; W-Pb; alloy control data; alloy reliability data; bump height uniformity; direct chip attach; eutectic Pb/Sn solders; fine pitch capabilities; flex on cap; flip chip technologies; high Sn content solders; low alpha solders; solder alloys; solder paste bumping; under bump metalization; Assembly; Chip scale packaging; Costs; Flip chip; Integrated circuit packaging; Probes; Semiconductor devices; Semiconductor thin films; Sputtering; Substrates;
Conference_Titel :
Advanced Packaging Materials. Proceedings., 3rd International Symposium on
Conference_Location :
Braselton, GA
Print_ISBN :
0-7803-3818-9
DOI :
10.1109/ISAPM.1997.581271
