Modeling of Micro Spring Tension Force for Vertical Type Probe Card Fabrication

For design of micro spring based vertical type probe card, accurate micro spring tension force modeling is essential to guarantee the probe testing performance and reliability. In this paper, neural network based micro spring model was developed to find optimal spring height and shift value for appropriate tension force. Modeling results are applied to design and fabrication of vertical type probe card using 80μm and 100μm tungsten wires for micro spring type probing on silicon substrate. Compare to conventional statistical modeling scheme, neural network based model showed superior modeling accuracy with limited a priori information. Proposed high pad density probe card can be applied to high-density multi-die testing as well as advanced bumping type chip test.