Contact Probe Tail Geometry for Stable Fine-Pitch Pad Contact
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Solution Overview
Problem
Contact probes with low contact force face issues of unstable contact resistance and alignment with interface board pads due to reduced pitch and pad size, leading to inaccurate test results and potential damage.
Innovation Solution
Designing a contact probe with a probe tail that has a reduced cross-sectional area at the contact end, featuring a tapered or indented shape, and a base portion for enhanced alignment and stability, along with a slot for reduced rigidity, ensuring precise alignment and stable contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If contact probes with low contact force are used to avoid damaging the device under test, then the device under test is protected from damage, but the contact resistance becomes unstable and test accuracy deteriorates
Solution Approach 1:
The contact probe is designed with non-uniform cross-sectional area along its length. The contact end portion has a smaller cross-sectional area than the body portion, creating local structural differentiation. This allows the contact end to exert lower contact force on the device under test while the body portion maintains sufficient rigidity for stable electrical connection at the interface board
Solution Approach 2:
The contact probe is segmented into distinct portions with different functional requirements: the body portion provides structural support and rigidity, while the contact end portion provides low-force contact with the device under test. This segmentation allows each portion to be optimized for its specific function without compromising the other
2Object-affected harmful factors
If contact probes with low contact force are used, then the device under test is protected, but the probe tail contact with interface board becomes unstable
Solution Approach 1:
The contact probe features local quality variation along its length, with the contact end portion having reduced cross-sectional area compared to the body portion. This structural differentiation enables the contact end to apply minimal force to protect the device under test, while the larger body portion maintains stable mechanical and electrical connection at the interface board
Solution Approach 2:
The probe structure is segmented into functional zones: the body portion optimized for stable interface board contact, and the contact end portion optimized for gentle device under test contact. This segmentation resolves the contradiction between protecting the device and ensuring measurement precision
3Manufacturing precision
If the pitch between contact probes is reduced to test smaller electronic components, then finer pitch testing is enabled, but the probe tail exceeds the edge of the contact pad on the interface board
Solution Approach 1:
The contact probe employs local quality differentiation with the contact end portion having smaller dimensions than the body portion. This allows the probe to achieve fine pitch positioning for testing small components while the smaller contact end surface prevents exceeding the contact pad edges on the interface board
Solution Approach 2:
The invention addresses the pitch problem by changing the dimensional characteristics of the contact end portion. By reducing the cross-sectional area at the contact end, the probe can operate at fine pitch intervals without the contact tail exceeding pad boundaries, effectively adding dimensional control to the pitch relationship
Data Source
AI summary
A contact probe defined with widths and thicknesses along first and second horizontal axes respectively and cross-sectional areas perpendicularly to a vertical axis includes a body portion for being curved at least along the first horizontal axis while disposed between upper and lower die units, a probe tip for contacting a contact pad of a device under test, and a probe tail including a contact end portion with a contact end surface for contacting a contact pad of an interface board. The contact end portion is at least partially smaller in width and thickness than the body portion, so that the contact end surface has an area smaller than a cross-sectional area of the body portion, thereby capable of stable contact with the contact pad of the interface board and prevented from exceeding its edge, obtaining stable contact resistance to ensure test results with stable and high accuracy.