Angled Probe Card Layout for Narrow Scribe Lane Wafer Testing
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Solution Overview
Problem
In wafer acceptable testing (WAT), the sliding of probe tips out of the scribe lane and the resulting shorting of metal lines due to electrically conductive particles pose challenges, requiring wider scribe lanes and testing pads, which are difficult to increase without occupying valuable wafer surface area.
Innovation Solution
The probes are angled at approximately 45 degrees when contacting the testing pads, allowing for longer slidable distances without escaping the scribe lane, thus reducing the risk of particle transfer between metal wires and enabling smaller scribe lane and testing pad widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the scribe lane and testing pad widths are increased to prevent probe tip escape and particle-induced shorts, then the reliability of WAT is improved, but the wafer surface area available for chip fabrication is reduced
Solution Approach 1:
The patent changes the angular parameter of probe contact with the testing pad. By optimizing the contact angle, the probe tip sliding distance is controlled to prevent escape from the scribe lane while minimizing the required scribe lane width, thus resolving the contradiction between reliability and wafer surface area utilization
Solution Approach 2:
The patent introduces a new dimensional parameter (contact angle) to control the probe tip trajectory. By adjusting the angle at which the probe tip contacts and slides across the testing pad, the system achieves reliable testing without requiring increased scribe lane width, effectively using angular dimension to solve the area constraint problem
2Reliability
If the scribe lane width is increased to accommodate probe tip sliding, then the risk of probe tip escape is reduced, but the manufacturing precision requirements for pad alignment are worsened
Solution Approach 1:
By changing the contact angle parameter, the patent reduces the lateral displacement of the probe tip during sliding. This allows for smaller scribe lane widths while maintaining probe tip containment, thereby reducing the tolerance requirements for pad alignment and positioning
3Manufacturing precision
If the contact area between probe tips and testing pads is shrunk to increase chip integrity, then the chip quality is improved, but the risk of particle-induced shorts is increased
Solution Approach 1:
The patent optimizes the contact angle parameter to control probe tip trajectory and sliding behavior. This allows for maintained or reduced contact area (preserving chip integrity) while ensuring probe tips remain within the scribe lane, preventing particle transfer to metal lines and eliminating the increased shorting risk
Data Source
AI summary
A probe card includes a circuit board, a fixing member, and a plurality of probes. The fixing member is fixed on the circuit board and has a through opening therein. The fixing member has opposite first and second sidewalls defining the through opening. Each of the probes includes an arm portion and a tip portion. One end of the arm portion is connected to the circuit board. The tip portion extends from the arm portion. The arm portions of the probes extend in substantially a same direction inclined to a direction perpendicular to the first sidewall of the fixing member in a top view.