2001 Fiscal Year Final Research Report Summary
MEMS Active Probe for Wafer-level Switching Contacter
| Project/Area Number |
12650049
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied physics, general
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| Research Institution | The University of Tokyo |
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Principal Investigator |
ITOH Toshihiro Research Center for Advanced Science and Technology, The University of Tokyo Associate Professor, 先端科学技術研究センター, 助教授 (80262111)
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| Co-Investigator(Kenkyū-buntansha) |
HOSODA Naoe Faculty of Engineering, The University of Tokyo Associate Professor, 大学院・工学系研究科, 助教授 (50280954)
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| Project Period (FY) |
2000 – 2001
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| Keywords | MEMS Probe Card / Fritting Contact / Contact Resistance / Microcantilever / Ni Electroplating / Wafer-level Contacter / Switching Contact / Atomic Force Microscope |
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| Research Abstract |
The purpose of this stude is to propose the new IC probe card which consists of actuator-integrated MEMS probes and enables the direct switching of contacts. Also, we have attempted to develop basic fabrication processes to realize it. Specifically, we have studied the fritting contact process which is a kind of electrical breakdown and is indispensable to make contact to Al pads with low forces using the MEMS probe. The important results are described below.
1. Characterization of fritting contact using newly developed measurement systems
We have realized the systems which can measure the fritting-contact characteristics with the force resolution of 10 μN and measured the characteristics of the contacts between several kinds of probes and pad metallurgy films of Al and Cu.
(1) Contact resistance decreases with increasing the maximum fritting current determined by the fritting voltage and circuit resistance.
(2) Ni probe can have lowest contact resistance among the conventional probes. When the limit current is larger than 100 mA, the resistance can be smaller than 1 Ω, even if the contact force is around 10μN.
2. Development of electroplated Ni microcantilever probes
We have proposed the micromachined Ni curl-up cantilever utilizing the difference of internal stress in electroplated Ni double layers and developed its fabrication process. The internal stress difference of about 400 MPa has successfully been obtained utilizing a salfamic acid bath for the lower low-stress layer and a Watts bath for the upper high-stress layer.
We have demonstrated that the Ni microcantilever probes can be applied to the test of IC with the pad pitch of less than 20 μm, by measuring the spring constant of the fabricated microprobes as 70 % of calculated value and showing their fritting characteristics are comparable to those of the conventional needle probes.
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