Chip on Glass Substrate 4-Probe Resistance Measurement
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Solution Overview
Problem
Existing methods for measuring connection resistance between a chip on glass (COG) substrate and an IC device lack accuracy, relying on subjective visual inspections or vision systems, which cannot ensure precise determination of compression stability.
Innovation Solution
A COG substrate design with specific pads and conductive patterns, along with a 4-probe resistance measuring method, where a current source and voltage meter are connected to measure the connection resistance between the substrate and IC device, allowing for quantitative assessment of connection stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection or vision systems are used to measure connection resistance, then the measurement process is simple, but the measurement precision is insufficient
Solution Approach 1:
The measurement system is segmented into separate functional components: current source connected to first and second conductive patterns, and voltage meter connected to third and fourth conductive patterns. This segmentation enables precise 4-probe measurement by isolating current injection from voltage measurement, resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
Additional conductive patterns (third and fourth patterns) are introduced as intermediaries to enable voltage measurement without current flow through the measurement path. These intermediary conductive patterns allow the voltage meter to measure potential difference independently from the current source, achieving high precision connection resistance measurement
2Measurement precision
If 4-probe resistance measuring method is used, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The additional conductive patterns serve multiple functions: they act as voltage sensing elements for the 4-probe measurement method, and simultaneously function as part of the overall conductive network on the substrate. This multi-functionality reduces the impact of device complexity while achieving improved measurement precision
3Reliability
If subjective visual inspection is used, then the ease of operation is high, but the reliability of connection stability determination is low
Solution Approach 1:
The 4-probe resistance measuring method provides quantitative feedback through precise resistance value measurements. The current source and voltage meter generate measurable electrical signals that directly indicate connection quality, replacing subjective visual inspection with objective, reliable data that clearly determines connection stability
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 and quantitative measurement of connection resistance, ensuring the stability of the compression part and reducing the risk of defective products by providing a reliable method for evaluating the connected state.
Implementation Method 1
Each of the first, second, and third pads and each of the first, second, and third bumps may be electrically connected to each other through an anisotropically conductive film containing conductive particles
Implementation Method 2
A connection resistance between the substrate and the IC device may be measured by a 4-probe resistance measuring method
Data Source
AI summary
A chip on glass substrate includes a substrate, first, second, and third pads that are arranged on the substrate and that are electrically connected to an IC device, and first to fourth conductive patterns. A first conductive pattern is arranged on the substrate, has one end electrically connected to the first pad, and has another end that is electrically floated. Second and third conductive patterns are arranged on the substrate, each have one end electrically connected to the second pad, and each have another end that is electrically floated. A fourth conductive pattern is arranged on the substrate, has one end electrically connected to the third pad, and has another end that is electrically floated.