高信頼半導体デバイス内残留ひずみ分布測定センサの試作とその応用

抄録

In this study, micro-scale strain sensors embedded in a silicon chip were developed in order to measure the local stress distribution in 3D semiconductor modules. This sensor utilized piezoresistive effect of single crystal silicon. The stress sensitivity at room temperature was 1.3 MPa/ and the stable operation of this sensor was confirmed in the temperature range from room temperature to 80oC at most. The stress distribution in a fine bump structure was measured using this sensor chip. The local distribution of the residual stress in a test 3D structure with various pitches of fine bumps was investigated. It was confirmed that the magnitude of the local deformation of the stacked chips varied a lot depending on the pitch of bumps. The magnitude of the residual stress increased monotonically with the pitch of bumps. Since the electronic performance of semiconductor devices is varied by mechanical stress, it is significantly important to control the stress distribution in complex 3D semiconductor modules for assuring high reliability.