RF Test Key Structure for Scribe Line Integration
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Solution Overview
Problem
Traditional RF test key structures are too wide to be set in a scribe line, increasing manufacturing difficulty and leading to inaccurate testing due to high inner resistance and differences in testing data compared to actual RF devices.
Innovation Solution
A RF test key structure positioned in a scribe line region with a substrate, device under test, and metal layers, featuring signal and ground pad regions arranged in a row parallel to the scribe line, with insulating openings to separate them, and large area metal layers for electromagnetic interference shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional RF test key structure is used, then testing coverage is achieved, but the structure width exceeds scribe line capacity and manufacturing difficulty increases
Solution Approach 1:
The patent transitions from a conventional wide layout to a narrow linear arrangement by repositioning all pad regions (signal and ground) in a single row within the scribe line. This dimensional reorganization allows the test key structure to fit within the constrained scribe line width while maintaining all necessary testing functions through strategic use of multiple metal layers and via connections.
2Length of moving object
If traditional RF test key structure with threadlike metal connecting line is used, then scribe line placement is achieved, but inner resistance increases and testing accuracy decreases
Solution Approach 1:
The patent fundamentally changes the electrical connection parameter from thin threadlike metal lines to large-area plate-like metal regions. By expanding the metal connecting regions into substantial plates with significant surface area, the electrical resistance is dramatically reduced, enabling accurate RF parameter measurements despite the constrained linear geometry within the scribe line.
Solution Approach 2:
The patent employs a composite multi-layer metal structure consisting of bottom metal layer, intermediate metal layer, and top metal layer, connected through via plugs. This composite construction creates low-resistance electrical pathways by combining multiple conductive layers, effectively reducing overall resistance and improving measurement precision while maintaining the compact linear form factor.
3Measurement precision
If large area metal layers are used for low resistance, then testing accuracy improves, but electromagnetic interference increases
Solution Approach 1:
The patent converts the potentially harmful electromagnetic interference into a beneficial shielding effect by strategically arranging ground pad regions adjacent to signal pad regions and connecting them through multiple metal layers. The large-area metal structures that could radiate interference instead function as electromagnetic shields, protecting the test structure from external RF interference and containing emitted signals, thus improving measurement accuracy.
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 accurate testing by minimizing resistance and reflecting the electronic characteristics of the RF device, while providing effective electromagnetic interference shielding to protect the test key structure.
Implementation Method 1
large area metal layers for electromagnetic interference shielding
Data Source
AI summary
A radio frequency test key structure includes a substrate, a bottom metal layer and a top metal layer. A narrow testing region is defined on the substrate. The bottom metal layer is positioned on the substrate and in the narrow testing region, and including an opening to expose parts of a device under test. The top metal layer is a metal pad in a sheet form, positioned in the narrow testing region and on the bottom metal layer. At least two signal pad regions and at least two ground pad regions are defined in the top metal layer. The signal pad regions and the ground pad regions are arranged in one row, and the row is parallel to the narrow testing region. Accordingly, the radio frequency test key structure can be positioned in a scribe line, and get an accurate testing result.