Device characteristic changes caused by packaging stress

The effect of packaging stress on device characteristics was determined experimentally. The stress sensitivity of the electronic characteristics of MOSFETs was measured by applying uni-axial stress to the transistor. The stress sensitivity was shown to depend on the transistor conduction type and the current flow direction. The packaging stress effect on a simple inverter amplifier using MOSFETs was measured by changing packaging materials. The residual stress distribution was also measured using stress sensing gauges embedded in LSI chips. The distribution of the amplifier gain change rate agreed well with the residual stress distribution in the LSI chip. The change rate was calculated based on the experimental results of the stress sensitivity of the MOSFETs electronic characteristics and the residual stress distribution. This predicted change rate agreed well with the measured data.