Test Jig Microstrip Impedance Matching for High Frequency Signals
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Solution Overview
Problem
Conventional test jigs for high frequency semiconductor packages fail to accurately test electrical characteristics due to mismatched characteristic impedances between contact pins and wiring, leading to signal attenuation.
Innovation Solution
A test jig with a microstrip line structure, featuring a grounding block and high frequency signal contact pin, where the grounding block has a protruding portion or cutout to adjust the characteristic impedance of the contact pin to match that of the wiring, ensuring accurate signal exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional test jig with contact pins is used, then the structure is simple and easy to manufacture, but the characteristic impedance of contact pins cannot be matched to the wiring, causing signal attenuation
Solution Approach 1:
The grounding block is designed with a protruding portion that locally modifies the grounding structure near the contact pin. This local modification adjusts the characteristic impedance of the contact pin region to match the wiring impedance (e.g., 50Ω), improving signal integrity without changing the overall simple test jig structure
Solution Approach 2:
The protruding portion of the grounding block changes the physical parameters (distance, area) of the grounding structure relative to the contact pin. By adjusting these parameters, the characteristic impedance of the contact pin is tuned to match the wiring impedance, preventing signal attenuation while maintaining structural simplicity
2Manufacturing precision
If the distance between contact pin and grounding block is determined by package size, then the test jig is easy to manufacture, but the characteristic impedance cannot be controlled
Solution Approach 1:
Instead of modifying the entire grounding block structure, only a localized protruding portion is added near the contact pin. This local modification provides precise control over characteristic impedance while keeping the rest of the grounding block simple and easy to manufacture
Solution Approach 2:
The protruding portion is pre-formed on the grounding block before assembly with the semiconductor package. This preliminary structuring ensures that the characteristic impedance is already optimized when the package is mounted, eliminating the need for post-manufacturing adjustments
Data Source
AI summary
A test jig is for testing electrical characteristics of a high frequency semiconductor device in a package having a ground electrode and a high frequency signal electrode. The test jig includes a test circuit substrate with a microstrip line structure, a grounding block and a high frequency signal contact pin. The test circuit substrate includes an insulating substrate, a ground conductor on a bottom surface of the insulating substrate and high frequency signal wiring on a top surface of the insulating substrate. The grounding block is disposed on the top surface of the insulating substrate and connected to the ground conductor. The high frequency signal contact pin is disposed on the top surface of the insulating substrate and connected to the high frequency signal wiring. The high frequency signal contact pin is spaced from the grounding block.