Display Signal Pad Structure for Reliable Bump Bonding
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Solution Overview
Problem
Existing display panels face challenges in achieving increased bonding reliability and processibility during the manufacturing of electronic apparatuses, particularly in the connection of signal pads and conductive layers.
Innovation Solution
The display panel incorporates an insulating layer made of elastomer, positioned between first and second conductive layers, with an opening exposing a portion of its top surface, allowing for enhanced bonding and micro-patterning capabilities, and includes a three-layer structure of titanium/aluminum/titanium for the conductive layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional signal pad structure without an insulating layer is used, then the manufacturing process is simpler, but the bonding reliability between the signal pad and bump electrode is reduced
Solution Approach 1:
An insulating layer is introduced as an intermediary component between the first conductive layer and the second conductive layer. This insulating layer includes an elastomer material that provides restoring force, thereby improving bonding reliability between the signal pad and bump electrode while managing the increased structural complexity through functional integration.
Solution Approach 2:
The signal pad adopts a composite structure consisting of multiple conductive layers (first and second conductive layers) separated by an insulating elastomer layer. This composite material approach enhances bonding reliability by combining the mechanical restoring force of the elastomer with the electrical conductivity of the metal layers, creating a multi-functional signal pad structure.
2Adaptability or versatility
If the second conductive layer is completely covering the first conductive layer, then the insulation is more complete, but the micro-patterning freedom and bonding flexibility are reduced
Solution Approach 1:
The second conductive layer is segmented or partially formed rather than being a complete continuous layer. This segmentation allows different regions of the signal pad to have different functional characteristics, enabling micro-patterning freedom and bonding flexibility while maintaining sufficient insulation where needed. The insulating layer fills the gaps between segmented conductive regions.
Solution Approach 2:
The signal pad structure exhibits local quality variations where the second conductive layer is selectively formed in certain regions while the insulating layer remains exposed in other regions. This local differentiation allows optimization of both insulation completeness and micro-patterning freedom by tailoring the conductive layer configuration to specific functional requirements of different pad regions.
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
This configuration enhances bonding reliability and processibility by providing a restoring force through the elastomer insulating layer and allows for high-freedom micro-patterning, improving the connection between signal pads and bump electrodes.
Implementation Method 1
The insulating layer may include elastomer
Data Source
AI summary
A display panel includes a pixel. A signal line is electrically connected to the pixel. A signal pad is connected to the signal line. The signal pad includes a first conductive layer electrically connected to a portion of the signal line. A second conductive layer is disposed on the first conductive layer. An insulating layer is disposed between the first conductive layer and the second conductive layer. An opening is defined in the second conductive layer. The opening exposes a portion of a top surface of the insulating layer.