Touch Panel Bonding Pad Structure for Connection Reliability
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Solution Overview
Problem
Touch panels often experience poor connection stability between the touch sensor array and signal circuit boards, leading to touch signal transmission issues and malfunctions, particularly due to structural defects in the bonding pads caused by process factors like film uniformity and substrate profile variations during the fabrication of large-sized display panels.
Innovation Solution
A bonding pad structure is designed with a first conductive layer, a first protective layer, a second conductive layer, and a second protective layer sequentially arranged on a substrate, where the second protective layer extends beyond the first protective layer to cover potential defects at the junction area between the layers, enhancing protection and connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bonding pad structure with single protective layer is used, then the device complexity is low, but the connection reliability deteriorates due to structural defects at junction areas
Solution Approach 1:
The bonding pad structure is segmented into multiple protective layers (first protective layer and second protective layer) with different functions. The first protective layer covers the circuit part while the second protective layer specifically covers the junction area, dividing the protection function into specialized segments that address different defect-prone regions separately.
Solution Approach 2:
The protective layers are arranged in multiple dimensions vertically above the conductive layer. The second protective layer is positioned at a different vertical dimension to specifically cover the junction area between the first protective layer and terminal part, adding dimensional depth to the protection structure.
2Manufacturing precision
If the second protective layer covers the junction area between first protective layer and terminal part, then the manufacturing precision improves by protecting structural defects, but the ease of manufacture deteriorates due to additional process steps
Solution Approach 1:
The second protective layer is formed in advance to cover potential defect areas before subsequent processing steps. This preliminary protective action prevents structural defects from developing during later manufacturing processes, ensuring film formation precision is maintained throughout production.
Solution Approach 2:
The second protective layer provides localized quality enhancement specifically at the junction area between the first protective layer and terminal part. This local quality improvement targets the most defect-prone region without requiring uniform enhancement across the entire bonding pad structure.
3Reliability
If the second protective layer extends beyond the first protective layer, then the reliability improves by covering potential defects, but the area occupied increases
Solution Approach 1:
The second protective layer extends locally only at the critical junction area where defects are most likely to occur, rather than uniformly across the entire bonding pad. This localized extension provides targeted reliability improvement with minimal area increase.
Solution Approach 2:
The second protective layer provides partial coverage that extends beyond the first protective layer only where needed for defect protection. This partial extension action covers the critical junction area without unnecessarily increasing the overall bonding pad area.
Data Source
AI summary
A touch panel and a peripheral circuit thereof are provided. Each bonding pad of the peripheral circuit includes a first conductive layer, a first protective layer, a second conductive layer, and a second protective layer sequentially arranged on a substrate from bottom to top. A covered area of the second conductive layer provided by the second protective layer is increased to cover a portion of the second conductive layer located above a junction area between the first protective layer and a terminal part of the first conductive layer, thereby increasing the reliability of the bonding pads.