Segmented Test Probe Contact Tips for MEMS Reliability
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Solution Overview
Problem
Conventional MEMS probe cards face issues with contact reliability and accuracy due to elastic deformation, increased contact resistance, and the need for more densely packed probes as semiconductor wafers grow larger and pads become closer, leading to defects and reduced reliability when probes wear or become contaminated.
Innovation Solution
A test probe design featuring split contact portions and elastic deformation portions that can independently contact the tested points, allowing for enhanced reliability and alternative contact options if one split contact portion is defective, with the elastic deformation portions configured to absorb deformation forces and reduce contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MEMS probes are densely arranged on the probe card to test larger semiconductor wafers with closer pads, then the testing capability is improved, but contact reliability deteriorates due to increased wear and contamination
Solution Approach 1:
The contact portion of the probe is divided into multiple independent contact tips (first contact tip, second contact tip, third contact tip) arranged in the probe width direction. This segmentation allows individual tips to be replaced or maintained independently, improving overall contact reliability while maintaining high-density probe arrangements for large wafer testing.
2Reliability
If the probe is compressed during testing, then electrical connection is achieved, but contact accuracy deteriorates due to elastic deformation causing sliding and movement
Solution Approach 1:
The contact portion is segmented into multiple contact tips that can independently accommodate deformation. When compression occurs, the elastic deformation portion deforms but the segmented contact tips maintain their relative positions and contact accuracy, preventing the sliding and movement that occurs in monolithic probe designs.
Solution Approach 2:
The probe structure employs asymmetric design where the contact portion width is greater than the elastic deformation portion width. This asymmetric configuration, combined with the segmented contact tips, allows the contact portion to maintain stability and accuracy while the narrower elastic portion absorbs the deformation during compression.
3Productivity
If repetitive testing is performed, then productivity is improved, but contact resistance increases due to tip wear and contamination
Solution Approach 1:
The contact portion is divided into multiple independent contact tips. During repetitive testing, if one tip becomes worn or contaminated, the other tips remain functional, maintaining low contact resistance and allowing the probe to continue effective operation. The segmented design enables selective maintenance or replacement of individual tips.
Solution Approach 2:
The probe structure allows for the replacement of worn contact tips while retaining the functional portions of the probe. This enables recovery of the probe's testing capability without discarding the entire probe assembly, maintaining productivity while managing contact resistance issues from repetitive use.
4Reliability
If the elastic deformation portion is compressed during testing, then contact is achieved, but the support member is adversely affected by the deformation forces
Solution Approach 1:
The contact portion is segmented into multiple tips distributed across the probe width. This segmentation distributes the compression forces across multiple contact points and corresponding elastic deformation sections, reducing the stress concentration on any single support member location and minimizing adverse effects on support member integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The test probe improves contact reliability and durability by allowing multiple contact points, reducing contact resistance, and enabling continued testing even if one contact portion is damaged, while minimizing the impact on support members during deformation.
Implementation Method 1
an elastic deformation portion connecting the first contact portion and the second contact portion and elastically deformed by compression in a probe axial line direction
Data Source
AI summary
A test probe for testing electric characteristics of an object to be tested. The test probe includes: a first contact portion; a second contact portion movable close to or away from the first contact portion; and an elastic deformation portion connecting the first contact portion and the second contact portion and elastically deformed by compression in a probe axial line direction, wherein at least one of the first contact portion and the second contact portion comprises a plurality of split contact portions separated by a first slit formed along a lengthwise direction. According to the present disclosure, the plurality of split contact portions are configured to independently contact the tested contact point of the object to be tested, thereby not only enhancing contact reliability but also securing contact reliability by an alternative split contact portion even though one of the split contact portions is defective or damaged.