Driving Chip Bump Structure for Stable Display Panel Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices face challenges in stably connecting driving chips to display panels, particularly due to issues with bump geometry and contact area, which can lead to instability and increased defect rates in the bonding process.
Innovation Solution
The use of a driving chip design featuring a first bump with a planar area of at least 400 μm² and a second bump with a smaller planar area, aligned with the first bump's side surfaces, allows for stable electrical connection through direct contact with pad wiring, enhancing bonding stability via increased pressure per unit area during ultrasonic bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single bump structure is used for connecting the driving chip to the display panel, then the manufacturing process is simple, but the bonding stability is insufficient
Solution Approach 1:
The single bump structure is divided into a first bump and a second bump with different planar areas. The first bump provides a larger bonding area for stable connection to the pad wiring, while the second bump provides a smaller contact area for precise positioning and electrical connection to the transistor. This segmentation resolves the contradiction by improving bonding stability through the first bump while maintaining manageable complexity through the functional differentiation of the two bumps.
Solution Approach 2:
Different regions of the bump structure are assigned different properties: the first bump has a larger planar area optimized for bonding stability with the pad wiring, while the second bump has a smaller planar area optimized for contact with the transistor gate electrode. This local differentiation of properties allows each bump to fulfill its specific function optimally, resolving the contradiction between reliability and complexity.
2Reliability
If a larger bump contact area is used, then the electrical connection is more stable, but the pressure per unit area during bonding is reduced
Solution Approach 1:
The bump structure is segmented into two bumps with different planar areas. The first bump with the larger planar area provides sufficient total contact area for stable electrical connection, while the second bump with the smaller planar area concentrates the bonding force to maintain adequate pressure per unit area during the bonding process. This segmentation allows the system to achieve both stability and sufficient bonding pressure.
Solution Approach 2:
The planar area parameter is differentiated between the first bump and second bump. By changing the planar area parameter to create a larger first bump and a smaller second bump, the design achieves both sufficient total contact area for electrical stability and concentrated pressure for effective bonding, resolving the contradiction between these two requirements.
3Reliability
If the bump length is increased to improve connection stability, then the bonding reliability improves, but the manufacturing precision requirements increase
Solution Approach 1:
The bump structure is segmented into a first bump and a second bump with different dimensions. The first bump can be optimized for connection stability with appropriate length, while the second bump provides precise positioning features. This segmentation allows independent optimization of each bump's dimensions for its specific function, improving connection stability while managing manufacturing precision requirements through functional differentiation.
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 improves the stability and reliability of the connection between the driving chip and the display panel, reducing defect rates and ensuring a secure electrical bond.
Implementation Method 1
enhancing bonding stability via increased pressure per unit area during ultrasonic bonding
Data Source
AI summary
A driving chip includes a body portion including a circuit. A first bump is electrically connected to the body portion. A second bump is disposed on the first bump. The second bump has a planar area less than a planar area of the first bump on a plane defined along a first direction parallel to an upper surface of the body portion. The first bump has a length of about 60 μm or more in the first direction, a side surface of the second bump is aligned with a side surface of the first bump along a second direction orthogonal to the first direction.