Contact Probe Inversion Prevents Shavings
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Solution Overview
Problem
Contact probes used in electrical characteristics tests of semiconductor devices experience issues such as shavings and twisting due to level differences, leading to reduced accuracy and durability, and potential short circuits caused by repetitive plastic deformation of conductive layers.
Innovation Solution
The electrical contact is designed with a sliding part having a stacked structure where an intermediate layer is sandwiched by outer layers, with the intermediate layer protruding relative to the outer layers, and a plating layer is formed to cover the side surfaces, preventing twisting and shavings, and improving durability by reducing roughening of the conductive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact probe is configured with a three-layer structure (conductive layer sandwiched between stress layers) to improve current resistant characteristics, then current resistance is improved, but side surfaces develop level differences that easily produce shavings
Solution Approach 1:
Instead of having the outer stress layers protrude beyond the intermediate conductive layer (which would cause the conductive layer to be shaved), the patent inverts the configuration so that the intermediate conductive layer protrudes beyond the outer stress layers. This inversion ensures that during overdrive, the stress layers contact the guide plate first and prevent the conductive layer from being shaved, while still maintaining good current resistant characteristics.
2Measurement precision
If the contact probe side surface is pressed against the guide plate through-hole inner surface during overdrive, then positioning accuracy is achieved, but the contact probe is twisted reducing positioning accuracy
Solution Approach 1:
The patent inverts the protrusion configuration so that the intermediate layer with better mechanical strength protrudes beyond the outer layers. This ensures that during overdrive, the intermediate layer contacts the guide plate first and prevents twisting deformation, thereby maintaining positioning accuracy.
Solution Approach 2:
The patent uses a composite three-layer structure where the intermediate layer is made of a material with different properties (better mechanical strength) than the outer layers. This composite structure allows the intermediate layer to resist twisting forces while the outer layers provide other necessary functions, thus maintaining positioning accuracy during overdrive.
3Speed
If the contact probe is shortened to improve high frequency characteristics, then high frequency performance is improved, but overdrive amount and probe pressure may be compromised
Solution Approach 1:
The patent employs a composite three-layer structure where the intermediate layer has high elasticity and the outer layers have appropriate mechanical properties. This composite construction allows the probe to be shortened for improved high frequency characteristics while the optimized material distribution ensures sufficient probe pressure and overdrive amount are maintained.
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
This configuration suppresses shavings and twisting, maintains accuracy, and enhances durability by preventing short circuits and ensuring consistent contact characteristics without compromising current resistance or overdrive performance.
Implementation Method 1
an elastic deformation part that is provided between the contact part and the terminal part, and is elastically deformed by compression force in a longer direction
Implementation Method 2
a sliding part that is supported by a through-hole of a guide plate movably in the longer direction
Data Source
AI summary
The present invention intends to suppress a contact probe from interfering with a guide plate to produce shavings. The present invention has stacked structure that sandwiches an intermediate metallic layer 12 between outer metallic layers 11 and 13, and includes: a contact part 2 that is brought into abutting with a test object; an elastic deformation part 4 that is elastically deformed so as to be curved in a predetermine direction of curvature N by compression force in the longer direction; and a fore end part 3 that is formed between the contact part 2 and the elastic deformation part 4 and supported by a through-hole 121 of a guide plate 120 so as to make the contact part 2 movable in the longer direction, in which side surfaces of the fore end part 3 formed in the direction of curvature N and a direction N′ opposite to the N of the elastic deformation part 4 are configured to include the three metallic layers 11 to 13, and on the side surfaces, the intermediate metallic layer 12 is configured to protrude relative to the outer metallic layers 11 and 13.