Display Panel Pad Structure for Reliable Ultrasonic Bonding
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Solution Overview
Problem
Existing display devices face reliability issues due to connection defects between pads and bumps during ultrasonic bonding, leading to potential failure in the bonding process.
Innovation Solution
The display panel incorporates protrusions with varying thicknesses and a conductive layer covering these protrusions, enhancing the frictional force between bumps and pads, thereby improving the connection reliability during ultrasonic bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protrusions with varying thicknesses are added to the pad structure, then the frictional force and connection reliability between pads and bumps are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The pad structure incorporates protrusions with varying thicknesses (first protrusions with greater thickness and second protrusions with smaller thickness) at different locations. This local variation in geometry creates differential frictional forces during ultrasonic bonding, improving connection reliability without requiring complete restructuring of the entire pad assembly.
Solution Approach 2:
The pad structure is segmented into multiple conductive layers (first conductive layer, second conductive layer) with distinct protrusion elements (first protrusions, second protrusions). This segmentation allows each layer and protrusion type to serve specific functional roles in the bonding process, enhancing overall connection reliability while maintaining manageable complexity through modular design.
2Stability of the object's composition
If multiple conductive layers with protrusions are used to enhance bonding, then the bonding stability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The invention utilizes parameter variation in protrusion thickness (first protrusions with greater thickness, second protrusions with smaller thickness) to create differential bonding characteristics. This parameter change approach allows optimization of bonding stability through geometric variation rather than requiring extreme precision in material composition or other critical parameters.
Solution Approach 2:
The pad structure employs asymmetric protrusion design where first protrusions and second protrusions have deliberately different thicknesses. This asymmetry creates varied frictional engagement during ultrasonic bonding, improving bonding stability through mechanical interlocking while the asymmetric geometry can be more tolerant to manufacturing variations compared to symmetric precision-critical designs.
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 design prevents or reduces connection failures between pads and bumps, enhancing the overall reliability of the display device by increasing the contact area and maintaining stable bonding.
Implementation Method 1
enhancing the frictional force between bumps and pads
Implementation Method 2
The driving chip may be bonded by an ultrasonic bonding process
Data Source
AI summary
A display panel includes a display area, a pad area adjacent to the display area, pixels disposed in the display area on a substrate, and pads disposed in the pad area on the substrate and electrically connected to pixels. Each of the pads includes a first conductive layer, at least one a first protrusion disposed on the first conductive layer, at least one second protrusion disposed on the first conductive layer and having a thickness smaller than a thickness of the at least one first protrusion, and a second conductive layer disposed on the first conductive layer and overlapping an upper surface of each of the at least one first protrusion and an upper surface of the at least one second protrusion in a plan view.