Two-dimensional dense-arrayed probe-cards with a hoe-shaped probing-tip micromachining technique

Presented is a MEMS probe-card with ultra dense two dimensional (2-D) probe arrays for wafer-level IC test. About 110000 probe tips can be simultaneously fabricated in a 4-inch wafer, with the 2-D tip pitch as 240 mum times 160 mum. The "hoe-shaped" microprobe structure is composed of one or two planar arms and an up-tilted tip, both of which are high-yield fabricated by metal micromachining techniques including electroplating. The measured spring constants for all the three types of designed probes agree well with the designed values. As both mechanical and electrical interconnections, the Sn/Ag solder-bumps feature excellent properties. The tested contact resistance values are always below 0.8Omega, while the current leakage between two adjacent probes is only 150 pA under 3.3 V.