Thin-Film Device Terminal Electrode Contact Area
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Solution Overview
Problem
Thin-film devices face challenges in securing reliable connections between conductor layers and terminal electrodes due to reduced contact areas, leading to variations in electromagnetic coupling and electrical characteristics, especially as devices are downsized and the number of terminal electrodes increases.
Innovation Solution
A thin-film device design featuring a substrate, protection film, and terminal electrodes where the terminal electrodes touch both the end face and top surface of the conductor layer, with a concave portion in the protection film exposing the top surface of the conductor layer to accommodate the terminal electrodes, thereby increasing the contact area and controlling the shape and location variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of conductor layers is reduced to decrease device dimensions, then the device profile is reduced, but the contact area between conductor layers and terminal electrodes is reduced, deteriorating connection reliability
Solution Approach 1:
The terminal electrode is designed to contact the conductor layer at multiple locations: the end face and multiple positions on the top surface (including intermediate points between the end face and the device end). This multi-point contact approach transforms a single-dimensional contact into a multi-dimensional contact structure, increasing the effective contact area without increasing the conductor layer thickness or the device overall dimensions.
2Reliability
If the wiring portion width is increased to increase contact area, then the connection reliability is improved, but the wiring density is reduced and device dimensions cannot be reduced
Solution Approach 1:
The contact area is segmented into multiple discrete contact points distributed across different surfaces (end face and top surface) rather than requiring a single large continuous contact area. This segmentation allows the terminal electrode to achieve sufficient total contact area while maintaining compact wiring dimensions and high wiring density.
3Adaptability or versatility
If the number of terminal electrodes is increased to improve device functionality, then the device performance is enhanced, but the variations in electromagnetic coupling and electrical characteristics increase due to reduced contact areas
Solution Approach 1:
The terminal electrode is designed with a predetermined multi-point contact structure that establishes reliable electrical connections before the device is fully assembled or operated. By pre-establishing multiple contact points on the conductor layer, the design ensures consistent electromagnetic coupling and electrical characteristics even as the number of terminal electrodes increases.
Data Source
AI summary
A thin-film device incorporates: a substrate; an insulating layer, a lower conductor layer, a dielectric film, an insulating layer, an upper conductor layer and a protection film that are stacked in this order on the substrate; and four terminal electrodes. The four terminal electrodes touch part of end faces of the upper conductor layer, and part of the top surface of the upper conductor layer contiguous to the end faces. The protection film has four concave portions, each of which has a shape that is recessed inward from the edge of the protection film except portions thereof corresponding to these concave portions. The four concave portions expose respective portions of the top surface of the upper conductor layer that touch the four terminal electrodes. The four concave portions accommodate respective portions of the four terminal electrodes.