Grounded Probe Structure for Full-Length Impedance Matching
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Solution Overview
Problem
Existing probe units cannot adjust the characteristic impedance of the tip and proximal portions of contact probes, leading to signal loss during high-frequency inspections of semiconductor integrated circuits and liquid crystal panels.
Innovation Solution
A probe unit design that includes signal pipes and ground pipes with adjustable air layers, through holes, and conductive units to connect the probes to external ground, allowing for impedance matching across the entire contact probe length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an air layer is provided around a contact probe to perform characteristic impedance matching, then the impedance of the central portion of the contact probe can be adjusted, but the characteristic impedance of the tip portion and proximal portion cannot be adjusted
Solution Approach 1:
The patent divides the contact probe into three distinct segments along its longitudinal axis: tip portion, central portion, and proximal portion. Each segment is equipped with its own air layer structure (signal pipe and ground member combination), allowing independent impedance adjustment for each segment. This segmentation enables comprehensive impedance matching throughout the entire probe length, resolving the limitation where only the central portion could be adjusted previously.
Solution Approach 2:
The patent introduces signal pipes and ground members as intermediary structures between the contact probe and the surrounding environment. These intermediaries create controlled air layers that mediate the electromagnetic field distribution around each segment of the probe. By adjusting the dimensions and positions of these intermediary elements, the characteristic impedance of each probe segment can be independently tuned to achieve overall impedance matching.
2Device complexity
If the probe unit structure is simplified, then the manufacturing cost is reduced, but the insertion loss increases due to improper impedance matching
Solution Approach 1:
The signal pipes and ground members serve multiple functions simultaneously: they provide mechanical support for the contact probe, create the necessary air layers for impedance matching, and define the electromagnetic field distribution. This multi-functionality allows the patent to achieve proper impedance matching without adding excessive structural complexity, as the same components perform both mechanical and electromagnetic functions.
Solution Approach 2:
The patent achieves impedance matching by adjusting geometric parameters of the signal pipes and ground members rather than changing the fundamental structure. By modifying dimensions such as the outer diameter of signal pipes, inner diameter of ground members, and the thickness of air layers, the characteristic impedance of each probe segment can be tuned. This parameter-based approach allows for flexible impedance control without requiring complex structural modifications.
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
Enables precise adjustment of the characteristic impedance of the contact probes, reducing signal loss and improving inspection accuracy and speed by matching impedance values across the probe's length.
Implementation Method 1
a ground member provided around each signal pipe and configured to form an air layer with the signal pipe
Implementation Method 2
a first conductive unit configured to electrically connect the first wiring part and the ground member; and a second conductive unit configured to electrically connect the second wiring part and the ground member
Data Source
AI summary
A probe unit includes: first contact probes each coming into contact with a target electrode on one end side in a longitudinal direction; a second contact probe connected to an external ground; a signal pipe disposed around each first contact probes; a ground member provided around each signal pipe and configured to form an air layer with the signal pipe; a probe holder including a plate-shaped first and second members; a first wiring part provided at least on a front surface of the first member and electrically connected to the second contact probe; a second wiring part provided at least on a front surface of the second member and electrically connected to the second contact probe; a first conductive unit configured to electrically connect the first wiring part and the ground member; and a second conductive unit configured to electrically connect the second wiring part and the ground member.