Guided Vertical Probe Array Sideways Scrub Motion
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Solution Overview
Problem
Conventional vertical probe technologies fail to effectively probe contact pads with pitches of 80 μm or less due to uncontrollable lateral deformation and mechanical fragility, leading to incorrect contact and handling issues.
Innovation Solution
An array of guided vertical probes with a sideways scrub motion, where probes are thin along the contact line and thick perpendicular to it, featuring a predetermined curvature in the X-Z plane, and supported by guide plates to control position and motion, allowing for precise contact with closely spaced pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional vertical probes are used for closely spaced contact pads, then the probe structure provides vertical contact capability, but the probes suffer from uncontrollable lateral deformation and mechanical fragility
Solution Approach 1:
The probe is designed with asymmetric cross-sectional dimensions where the width along the contact line (X-direction) is made thin to accommodate closely spaced pads, while the thickness perpendicular to the contact line (Y-direction) is made thick to provide mechanical robustness and resistance against lateral deformation. This asymmetric geometry resolves the contradiction by allowing the probe to be both thin enough for fine-pitch contact and thick enough for mechanical strength.
2Manufacturing precision
If the probe width is reduced to probe closely spaced contact pads, then the probing capability for fine-pitch pads is improved, but the probe becomes more fragile and harder to handle
Solution Approach 1:
The probe employs asymmetric cross-sectional dimensions with thin width (X-direction) for precise probing of closely spaced pads and thick thickness (Y-direction) for easy handling and mechanical robustness. This asymmetric design allows the probe to achieve fine-pitch probing capability while maintaining ease of operation and handling.
Solution Approach 2:
The probe design shifts the mechanical strength requirement from the X-dimension (contact line direction) to the Y-dimension (perpendicular to contact line). By making the probe thick in the Y-direction while keeping it thin in the X-direction, the design achieves both fine-pitch probing capability and handling ease through dimensional redistribution of mechanical properties.
3Manufacturing precision
If guide plates are added to control probe motion, then the scrub motion is controlled and contact precision is improved, but the device complexity increases
Solution Approach 1:
Guide plates are introduced as intermediary components between the probe array and the support structure. These guide plates contain slots that constrain probe motion and control the scrub motion during contact, thereby improving contact precision while isolating the complexity of motion control from the probes themselves.
Solution Approach 2:
The guide plates are pre-configured with slots that define the permissible motion paths of the probes before contact is made. This preliminary arrangement of guide plates establishes the scrub motion control and contact precision requirements in advance, simplifying the probe design while ensuring precise contact through the pre-defined geometric constraints.
Data Source
AI summary
Improved probing of closely spaced contact pads is provided by an array of guided vertical probes that has a sideways scrub relative to the line of contact pads. With this orientation of scrub motion, the probes can be relatively thin along the contact line, and relatively thick perpendicular to the contact line. The thin dimension of the probes allows for probing closely spaced contact pads, while the thick dimension of the probes provides mechanical robustness and current carrying capacity. The probes have a predetermined curvature in a plane including the contact line, to help determine the amount of scrub motion during contact. In a preferred embodiment, an array of probes is provided for probing two closely spaced and parallel rows of contact pads, offset from each other by half the contact pad pitch.