Abstract
A novel piezoresistive three-axis accelerometer featuring a ring-shaped beam for stress-relaxation against shrinkage force of resin-mold packaging was improved to achieve remarkably high shock durability of 20000 G By a simulated shock test, fracture mechanism was estimated that the ring was broken due to a momentary increase in tensile stress just after a mass crashed into a cap. Therefore, the ring shape was improved in strength against tensile load without reduction in stress-relaxation effect, and gaps between the mass and the caps were reduced to 2 μm for softenning the crash. Shock durability over 20000 G was finally confirmed with improved test samples.
