Self-Cleaning Probe Skate for Convex Pad Testing
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Solution Overview
Problem
Current probe designs for semiconductor wafer testing are sensitive to overdrive motion, leading to inconsistent scrubbing and debris accumulation, which damages conductive pads and requires invasive cleaning processes, disrupting fabrication throughput and shortening probe utility.
Innovation Solution
A probe with a self-cleaning skate having a generally square front end, a round back end, and a flat middle section, designed to pivot and translate during overdrive motion, effectively displacing debris away from the conductive pad without breaching it, and utilizing a cleaning sheet for debris adhesion to remove debris from the skate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional probe tip is used for scrubbing conductive pads, then the non-conductive debris layer can be removed, but the probe becomes sensitive to overdrive motion causing inconsistent scrubbing depth and debris accumulation
Solution Approach 1:
The probe tip is segmented into distinct functional zones: a skating portion with a broad flat bottom surface for controlled scrubbing, a transition portion connecting to the contact portion, and a contact portion for electrical contact. This segmentation allows each zone to perform its specific function independently, with the skating portion providing consistent scrubbing depth regardless of overdrive motion variations.
Solution Approach 2:
The broad flat bottom surface of the skating portion acts as a cushioning element that absorbs and distributes overdrive motion before it reaches the contact portion. This beforehand cushioning prevents excessive sensitivity to overdrive motion by providing a stable platform that maintains consistent scrubbing depth even when subjected to variable forces.
2Reliability
If the probe applies strong scrubbing force to remove debris, then the non-conductive layer is effectively removed, but the conductive pad may be damaged or breached
Solution Approach 1:
The probe tip incorporates local quality differentiation where the skating portion has a broad flat bottom surface specifically designed for gentle, controlled scrubbing of the non-conductive debris layer, while the contact portion is optimized for electrical contact. This localized functional differentiation allows effective debris removal in the skating zone without concentrating excessive force that could damage the conductive pad.
Solution Approach 2:
The skating portion performs a partial scrubbing action by maintaining consistent contact with the pad surface through its broad flat geometry, removing debris gradually without the excessive force that would cause pad breach. The design accepts that complete debris removal may require multiple passes rather than applying excessive force in a single action.
3Ease of operation
If the probe tip geometry is optimized for scrubbing control, then consistent scrubbing depth is achieved, but debris accumulates on the probe tip requiring frequent cleaning
Solution Approach 1:
The skating portion is designed with a broad flat bottom surface that extends in the lateral dimension, creating a wide skating surface that prevents debris accumulation by distributing contact forces over a larger area. This dimensional expansion in the lateral direction allows debris to be spread out rather than concentrated at a single point, reducing the frequency of cleaning required.
4Duration of action of moving object
If invasive cleaning processes are used to remove debris from probe tips, then probe utility is extended, but fabrication throughput is disrupted and probe tips are degraded
Solution Approach 1:
The skating portion's broad flat bottom surface is designed to self-clean by distributing contact forces and preventing debris adhesion in the first place. The geometry allows debris to be naturally shed during normal probe operation rather than requiring invasive cleaning processes, thereby maintaining fabrication throughput while extending probe utility through reduced wear from cleaning operations.
Data Source
AI summary
A probe for engaging a conductive pad is provided. The probe includes a probe contact end for receiving a test current, a probe retention portion below the contact end, a block for holding the probe retention portion, a probe arm below the retention portion, a probe contact tip below the arm, and a generally planar self-cleaning skate disposed perpendicular below the contact tip. The self-cleaning skate has a square front, a round back and a flat middle section. The conductive pad is of generally convex shape having a granular non-conductive surface of debris and moves to engage the skate, whereby an overdrive motion is applied to the pad causing the skate to move across and scrub non-conductive debris from the pad displacing the debris along the skate and around the skate round back end to a position on the skate that is away from the pad.