Display Chip Bump Layout to Prevent Pad Cracking on Substrates
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Solution Overview
Problem
Existing display devices face technical difficulties in directly mounting drive circuit chips on substrates due to cracking or breaking of pads and wirings under pressure and temperature stress, especially in flexible display devices.
Innovation Solution
A display device design featuring conductive pads arranged in parallel on a substrate and corresponding bumps on the drive circuit chip arranged in a zigzag pattern to minimize pressure concentration and enhance stability during mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If drive circuit chip is directly mounted on substrate, then integration degree is improved, but pads and wirings are cracked or broken due to pressure and temperature stress
Solution Approach 1:
The patent applies asymmetry by arranging bumps in a zigzag pattern rather than a straight linear arrangement. This asymmetric configuration distributes the mounting pressure more evenly across the substrate, preventing concentration of stress at single points and thereby reducing crack formation while maintaining direct chip mounting integration
Solution Approach 2:
The patent transitions from a one-dimensional linear bump arrangement to a two-dimensional zigzag pattern. This dimensional change allows the bumps to distribute pressure across a wider area of the substrate, improving both integration and crack resistance by engaging multiple spatial dimensions for stress distribution
2Device complexity
If drive circuit chip is directly mounted on substrate, then integration degree is improved, but pads and wirings are broken due to temperature stress
Solution Approach 1:
The zigzag bump arrangement creates an asymmetric structure that provides thermal expansion accommodation. The alternating pattern allows for differential thermal movement between the chip and substrate, reducing temperature-induced stress concentration and preventing wiring breakdown during direct mounting
Solution Approach 2:
The zigzag bump configuration acts as a pre-designed cushioning structure that anticipates thermal stress. The geometric pattern inherently absorbs and distributes thermal expansion forces before they can cause damage to pads and wirings, providing protective cushioning against temperature-related failures
3Device complexity
If bumps are arranged in parallel with conductive pads, then electrical connection is simplified, but pressure concentration occurs during mounting
Solution Approach 1:
The patent introduces asymmetry by offsetting bump positions in a zigzag pattern rather than aligning them directly parallel with pads. This asymmetric offset distributes the contact pressure across multiple adjacent pads, preventing pressure concentration at any single point while maintaining electrical connectivity
Data Source
AI summary
A display device includes a substrate, conductive pads arranged on the substrate over a plurality of rows, and a drive circuit chip including bumps arranged over a plurality of rows to be electrically connected with the conductive pads, and the conductive pads arranged in a same row are arranged in parallel, and the bumps arranged in a same row are arranged in a zigzag form so as to be partially shifted.