Die attach by diffusion Sn-Ag-Sn soldering in high temperature electronics applications

摘要

The aim of this work was assessment of application diffusion soldering in die attachment for the electronic devices operating at temperatures above 300 °C. Assembly process was based on the intermetallic compound formation in Sn, Cu and Ag systems at temperatures above Sn melting point. New-created compounds should be thermally stable in high temperatures. The influence of the following parameters: temperature, pressure, process time and application of flux on mechanical strength (shear strength) was investigated. It was concluded that mechanical strength of joints is good and influence of some of the process parameters is stronger than others. The best soldering results were achieved for process were flux was applied, temperature at 395 °C, pressure higher than 10 MPa, and process time longer than 10 minutes. In the next series of experiment the soldering temperature was decreased to the range 270 °C ÷ 300 °C and still good mechanical strength of joint was possible. In diffusion soldering it is necessary to apply no-clean flux. It makes soldering process easier and better mechanical properties were achieved.