Journal article
MEMS Vertical Probe Cards With Ultra Densely Arrayed Metal Probes for Wafer-Level IC Testing
We have developed a MEMS probe-card technology for wafer-level testing ICs with 1-D line-arrayed or 2-D area-arrayed dense pads layouts. With a novel metal MEMS fabrication technique, an area-arrayed tip matrix is realized with an ultradense tip pitch of 90 mum times196 mum for testing 2-D pad layout, and a 50-mum minimum pitch is also achieved in line-arrayed probe cards for testing line-on-center or line-on-perimeter wafers.
By using the anisotropic etching properties of single-crystalline silicon, novel oblique concave cavities are formed as electroplating moulds for the area-arrayed microprobes. With the micromachined cavity moulds, the probes are firstly electroplated in a silicon wafer and further flip-chip packaged onto a low-temperature cofired ceramic board for signal feeding to an automatic testing equipment.
The microprobes can be efficiently released using a silicon-loss technique with a lateral underneath etching. The measured material properties of the electroplated nickel and the Sn-Ag solder bump are promising for IC testing applications. Mechanical tests have verified that the microprobes can withstand a 65-mN probing force, while the tip displacement is 25 mum, and can reliably work for more than 100 000 touchdowns.
The electric test shows that the probe array can provide a low contact resistance of below 1 Omega, while the current leakage is only 150 pA at 3.3 V for adjacent probes.
Language: | English |
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Publisher: | IEEE |
Year: | 2009 |
Pages: | 933-941 |
ISSN: | 19410158 and 10577157 |
Types: | Journal article |
DOI: | 10.1109/JMEMS.2009.2021815 |
Anisotropic magnetoresistance Automatic testing Ceramics Dense-arrayed vertical tips Etching Fabrication IC testing Integrated circuit testing MEMS fabrication technique MEMS probe-card technology MEMS vertical probe cards Micromechanical devices Packaging machines Probes Silicon Sn-Ag solder bump anisotropic etching property area-arrayed microprobes area-arrayed tip matrix automatic testing equipment contact resistance current leakage electroplated nickel electroplating electroplating moulds etching flip-chip devices flip-chip packaged integrated circuit testing lateral underneath etching leakage currents line-arrayed probe cards line-on-center wafer line-on-perimeter wafers low-temperature cofired ceramic board micromachined cavity moulds micromachining micromechanical devices oblique concave cavity probe card probes signal feeding silicon wafer single-crystalline silicon ultra densely arrayed metal probes ultradense tip pitch wafer-level IC testing