Development and application of the stress sensing test chip for IC plastic packages.

Abstract

A stress sending Si chip utilizing the piezoresistive effect of Si single crystals has been developed. This chip can measure 3-dimensional stress components, σx, σy, σz and shear stress τxy in the chip surface. The stress sensitivity is 0.1 MPa in the range of -100 MPa to 100 MPa. Temperature sensors are arranged in the chip and they have linear response between -100°C and 200°C. This chip is useful for the structural design and reliability tests of IC packages. The residual stress in a chip after the die bonding process is measured using this chip. It is found that rubber paste is useful in reducing stress in that process.