Compliant Vertical Probe Assembly for Oxide-Penetrating Wafer Contact
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Solution Overview
Problem
The challenge in electrical test assemblies is the formation of a metal oxide layer on wafer die pads due to oxidation, which affects conductance and requires precise force to penetrate for accurate testing, while excessive force can cause probe wear or damage.
Innovation Solution
A vertical probe assembly with resilient compliant probes and guide plates, featuring conductive materials and non-conductive substrates, allows for controlled deformation to ensure proper contact without damaging the pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If increased force is applied to penetrate the oxide layer, then electrical contact quality is improved, but probe wear and damage increases
Solution Approach 1:
The patent changes the physical state and properties of the contact element by using a compliant material that can deform elastically. This allows the contact force to be applied dynamically - sufficient to penetrate oxide layers during testing, but reversible to prevent permanent probe wear. The compliant contact element's ability to change its deformation parameter resolves the contradiction between needing high contact force for measurement precision and avoiding excessive force that causes probe damage.
2Force
If rigid probes are used to ensure stable contact, then contact force is sufficient, but co-planarity and uniform contact across the probe head is compromised
Solution Approach 1:
The patent employs a compliant contact element that functions as a flexible component within the probe assembly. This flexible element can deform to accommodate variations in wafer surface flatness and probe positioning, ensuring that all probes maintain uniform contact force across the entire probe head array. The compliance of the contact element compensates for manufacturing tolerances and maintains co-planarity without requiring extremely rigid structures.
3Reliability
If the contact force is reduced to prevent pad cracking, then probe wear is minimized, but the oxide layer cannot be effectively penetrated
Solution Approach 1:
The compliant contact element introduces dynamic behavior to the contact interface. During the testing process, the compliant material deforms to generate sufficient contact force to penetrate oxide layers when needed. The dynamic deformation allows the system to achieve high contact forces temporarily for oxide penetration while returning to a lower stress state that prevents pad cracking and maintains probe reliability. This dynamic adaptation resolves the contradiction between needing high force for measurement and maintaining low force for reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures consistent and accurate electrical testing by minimizing force applied to the oxide layer, reducing probe wear, and maintaining contact integrity.
Implementation Method 1
A vertical probe assembly with resilient compliant probes and guide plates, featuring conductive materials and non-conductive substrates, allows for controlled deformation to ensure proper contact without damaging the pads.
Data Source
AI summary
A vertical probe assembly having a resilient compliant probe, a first guide plate, a second guide plate, and a third guide plate is disclosed. The probe may include an upper portion, a lower portion, and a stopper structure positioned between the upper and lower portions of the first probe. The first, second, and third guide plates may be formed from a non-conductive substrate and separated by one or more spacers. The first, second, and third guide plates may also include a first, second, and third hole, respectively. The first, second, and third holes may be vertically aligned. The probe may be positioned within the first, second, and third holes such that the upper portion extends through the first hole, the lower portion extends through the second and third holes, and the stopper structure contacts a surface of the second guide plate that faces the first guide plate.