Strain effects in van der Pauw (VDP) stress sensor fabricated on (111) silicon in electronic packages

摘要

We have fabricated VDP (van der Pauw) stress sensors on (111) silicon surfaces. Traditionally, VDP structures were used for the measurement of sheet resistance, R_s. However, as stress sensors, these are currently widely used to measure the die stresses in electronic packages because of their characteristics of higher sensitivities compared to the conventional resistor sensors. This work focuses on a study of strain effects in VDP stress sensors fabricated on (111) silicon, which were generally ignored in previous works, for the precise measurements of die stresses in electronic packages. Measurements were performed using resistor stress sensors as well as VDP stress sensors fabricated on (111) silicon, and corrected values of the Magnification factor coefficients are confirmed experimentally by comparing pairs of VDP stress sensor and resistive stress sensor. Also, the stress sensitivity was observed to be approximately 10 % larger for p-type VDP sensors compared to n-type VDP sensors. Four-point bending (4PB) was used to generate the required stress in strip-on-beam samples.