Active Matrix Substrate Insulating Layer Extraction
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Solution Overview
Problem
Conventional active matrix substrates face reliability issues due to electrical disconnection caused by water vapor absorption in the insulating layer, leading to display abnormalities, and production yield reduction due to potential short circuits during the bonding process with IC chips.
Innovation Solution
The active matrix substrate design includes conducting pads arranged in rows with contact holes that entirely expose the pads, eliminating insulating material below the IC chip bumps and covering wire intervals with the insulating unit to prevent electrical disconnections and short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating layer containing resin is provided below the IC chip, then the IC chip is protected and electrically isolated, but the resin absorbs water vapor and expands causing electrical disconnection between bumps and metal pads
Solution Approach 1:
The patent removes the insulating layer from the region directly below the IC chip bumps, extracting only the necessary portion while maintaining insulation elsewhere. This eliminates the water vapor absorption and expansion issue in the critical bonding area while preserving protection in other regions.
Solution Approach 2:
The insulating layer is applied selectively: present in regions where protection is needed (side regions, wire areas) and absent in regions where electrical connection is critical (below metal pads and bumps). This local differentiation resolves the contradiction between protection and connection reliability.
2Reliability
If the insulating layer is entirely omitted below the IC chip bumps, then electrical disconnection is avoided, but short circuits may form between metal pads and adjacent metal wires during bonding
Solution Approach 1:
The insulating layer is removed only from the specific region below the bumps and metal pads where electrical connection is needed, while retaining it in adjacent regions to prevent short circuits with metal wires. This selective extraction resolves both issues simultaneously.
Solution Approach 2:
Different regions have different insulating layer configurations: no insulation below pads/bumps for reliable connection, but insulation present in side regions and wire areas for short circuit prevention. This local quality differentiation resolves the contradiction.
3Manufacturing precision
If multiple contact holes are defined corresponding to each metal pad, then precise electrical connection is achieved, but manufacturing complexity increases
Solution Approach 1:
Multiple contact holes are merged into a single opening structure that exposes multiple metal pads simultaneously. This combining approach maintains precise electrical connection for all pads while simplifying the manufacturing process by reducing the number of individual contact hole operations.
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 the reliability and production yield of display devices by preventing electrical disconnections and short circuits, even when the insulating material expands, ensuring precise connections and improved manufacturing efficiency.
Implementation Method 1
The insulating layer 28 generally contains resin, so the insulating layer 28 tends to expand when absorbing water vapor
Data Source
AI summary
An active matrix substrate includes a substrate and an insulating unit arranged on the substrate. The substrate includes a display region and a periphery circuit region beside the display region. The periphery circuit region has at least a chip connecting unit. Each chip connecting unit includes a number of connecting elements. Each of the connecting elements includes a conducting pad and a wire electrically connected to the conducting pad. The conducting pads of the connecting elements are arranged in at least two rows. The insulating unit has a number of contact holes corresponding to the conducting pads so that each of the conducting pads is entirely exposed by the corresponding contact hole. The active matrix substrate is applied to a display device to increase reliability of the display device and improve the quality of the display device.