Chip-on-Film Package Time-Division Multiplexing Test Pad
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Solution Overview
Problem
The increasing complexity and pin count of integrated circuits (ICs) lead to challenges in IC testing, particularly for high pin count chip-on-film (COF) packages, where the number of input and output terminals exceeds the capabilities of existing testers, necessitating frequent replacements due to compatibility issues and high fabrication costs.
Innovation Solution
An electronic device with a chip-on-film package that employs a flexible substrate, a core circuit unit, multiple output pads, and switching elements to transmit multiple output signals to a common test pad in a time-division multiplexing and many-to-one manner, reducing the number of test pads and enhancing tester compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple output pads are used for high pin count IC testing, then testing capability is improved, but tester compatibility deteriorates due to resource limitations
Solution Approach 1:
Multiple output pads are merged into a single common test pad through switching elements. The patent connects multiple output pads (first output pad, second output pad, etc.) to a common test pad via switching elements, allowing multiple signals to be tested through one pad by time-division multiplexing, thereby reducing the number of test pads required and improving tester compatibility.
Solution Approach 2:
The switching elements dynamically connect different output pads to the common test pad based on test requirements. The switching elements can be controlled to connect any output pad to the common test pad at different times, enabling dynamic resource allocation and maintaining testing capability while reducing pad quantity.
2Adaptability or versatility
If the number of test pads is reduced, then tester compatibility is improved, but testing functionality deteriorates due to fewer available test points
Solution Approach 1:
The switching elements operate periodically to connect different output pads to the common test pad in sequence. By time-division multiplexing, each output pad is connected to the common test pad at different time intervals, allowing all output pads to be tested through a single pad while maintaining full testing functionality.
Solution Approach 2:
Switching elements serve as intermediaries between multiple output pads and the common test pad. The switching elements control the connection between output pads and the common test pad, enabling multiple signals to be transmitted through a single pad at different times, thus preserving testing capability while reducing pad count.
3Adaptability or versatility
If IC pin count increases, then circuit functionality is improved, but testing complexity deteriorates due to more terminals to test
Solution Approach 1:
Multiple output pads from high pin count ICs are merged into a single common test pad through switching elements. This consolidation reduces the number of test connections required, simplifying the testing process while maintaining the ability to test all output terminals of complex high pin count circuits.
Data Source
AI summary
An electronic device with COF package is provided. The electronic device includes a flexible substrate, a core circuit unit, multiple output pads, multiple switching elements, and a common test pad. The flexible substrate includes a non-cutting-out area and a cutting-out area. The core circuit unit and output pads are disposed in the non-cutting-out area. First terminals of the switching elements are respectively and electrically connected to output pads of the core circuit unit, and second terminals of the switching elements are respectively and electrically connected to the output pads. The common test pad is disposed in the cutting-out area and electrically connected to the output pads. In a test stage, the switching elements are sequentially turned on such that one of multiple output signals of the core circuit unit is transmitted to the common test pad.