Manufacture of Ni Microprobe using X-Ray Lithography and Plating Method-Behavior of Ni-plated Materials at a Constant Temperature Under Stress

摘要

3-dimentional Ni microprobe has been developed using an X-ray lithography and electroplating method for IC microchip. A probe for the actual probe card must be durable enough to repeat touch 10,000 times or more at an ambient temperature of approximately 358K. In order to evaluate the durability of Ni-plated material that forms the microprobe, a simplified test piece was used. As a result, it was found that despite the deformation being within the limit of elasticity, a phenomenon similar to creep caused the deformation to persist even after the stress had been relieved. Although such a phenomenon has already been verified in ordinary materials at high temperature, it has now also been verified in Ni-plated materials at low temperature. This can probably be attributed to the fact that Ni-plated materials have a minute grain size of several tens of nanometers, and because the Ni coating absorbed hydrogen and impurities from aqueous solution during plating. After heating the Ni-plated material to approximately 373 to 573K, the deformation was dwindling noticeably. It has been established, therefore, that heat treatment is effective in improving the durability of Ni-plated structures manufactured by an X-ray lithography and electroplating method.