Rectangular Cross-Section Guided Vertical Probes for Sub-80 μm Pitch
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Solution Overview
Problem
Conventional vertical probe technologies fail to effectively make temporary electrical contact with contact pads spaced 80 μm or less, due to uncontrollable lateral deformation and mechanical fragility of probes at reduced pitches.
Innovation Solution
The use of guided vertical probes with a sideways scrub motion, featuring probes with a rectangular cross-section and curvature in the X-Z plane, and positioned within guide plates to control lateral and vertical positioning, allowing for controlled scrub motion and increased mechanical robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional vertical probes are used for small pitch contact pads (80 μm or less), then probe density increases, but lateral deformation and mechanical fragility worsen
Solution Approach 1:
The probe cross-section is changed from circular to rectangular, utilizing the dimensional advantage of having different dimensions in different directions. The rectangular cross-section allows the probe to be thinner in the pitch direction (X-dimension) while maintaining sufficient thickness in the lateral direction (Y-dimension) for mechanical strength, effectively solving the contradiction between small pitch and mechanical robustness
Solution Approach 2:
The probe is constructed with a composite structure consisting of a shaft portion and a tip portion made of different materials. The shaft portion provides mechanical strength and flexibility, while the tip portion provides durability and controlled deformation characteristics, allowing the probe to maintain both small pitch capability and mechanical robustness
2Manufacturing precision
If conventional vertical probes are used for small pitch contact pads, then probe array density increases, but lateral deformation control worsens
Solution Approach 1:
By changing the probe cross-section to rectangular, the probe gains different dimensional characteristics in different directions. The Y-dimension (lateral thickness) can be made sufficiently large to resist lateral deformation and provide stability, while the X-dimension (pitch-direction thickness) can be made small to achieve high density probing of contact pads spaced 80 μm or less
Solution Approach 2:
The rectangular cross-section creates local quality differences in the probe structure, with the Y-dimension providing enhanced lateral stability and the X-dimension providing compact pitch capability. This localized dimensional differentiation allows the same probe structure to simultaneously achieve both small pitch and lateral deformation control
3Manufacturing precision
If probe thickness is reduced for small pitch probing, then pitch capability improves, but mechanical robustness worsens
Solution Approach 1:
The rectangular cross-section enables the probe to have different thicknesses in different dimensions. The probe can be thin in the X-dimension (pitch direction) to achieve small pitch capability while being sufficiently thick in the Y-dimension (lateral direction) to maintain mechanical robustness, effectively decoupling these two requirements
4Manufacturing precision
If guide plates are added to control probe positioning, then positioning precision improves, but device complexity increases
Solution Approach 1:
The positioning function is segmented between the guide plate structure and the probe structure. The guide plate provides the positioning framework with openings that define probe locations, while the probe shaft and tip provide the positioning elements that engage with the guide plate. This segmentation allows each component to be optimized independently while working together to achieve precise positioning
Data Source
AI summary
The present invention is a set of layered probes that make electrical contact to a device under test. The layered probes are disposed within openings of at least one guide plate. The guide plate surrounds the probes via the openings. The layered probes have a base end, an opposing tip end and a shaft connecting the base end to the tip end. The base end can have a positioning device that extends away from the base end.