Microassembly of a piezoelectric miniature motor

An assembly method for the fabrication of a piezoelectric miniature motor is presented. The fabrication is done by placement and soldering of piezoceramic elements onto a silicon substrate. The assembly of the miniature motor demands high precision (+/-5 mu m), four-axes positioning which is fulfilled by a special micropositioning stage. A particular assembling sequence is used and critical process and performance parameters are evaluated. One of the important factors is the joint strength between the piezoceramic element and the silicon substrate. A joint strength as high as 100 MPa has been measured which would allow for torque values in the range of 14 mNm for a 4 mm diameter motor.