Substrate Stepwise Structure for Hole Coating Adhesion
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Solution Overview
Problem
Existing substrates for electronic devices, such as liquid crystal display panels, face issues with thick and steep tapered portions in insulating films, leading to poor coating quality and adhesiveness of upper layers, which can result in increased contact resistance, corrosion, and film peeling due to incomplete coating of holes.
Innovation Solution
A substrate with a stepwise structure formed by protrusions in the first and second insulating films, where the upper layer coats these steps, improving coating quality and adhesiveness, and a method involving dry etching to create holes through multiple insulating films simultaneously, using different etching gases to control the etching process and reduce hole size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to form holes through multiple insulating films, then the holes can be formed, but the tapered portions become thick and steep, resulting in poor coating quality and adhesiveness of upper layers
Solution Approach 1:
The patent divides the single etching process into two sequential etching steps: a first etching step that forms an initial hole through the insulating films, and a second etching step that enlarges the hole opening while controlling the tapered portion shape. This segmentation allows independent optimization of hole formation and tapered portion control, resolving the contradiction between hole formation precision and coating adhesiveness.
Solution Approach 2:
The first etching step performs preliminary hole formation through the insulating films before the second etching step enlarges the opening. By pre-forming the hole with controlled depth and shape, the subsequent enlargement can focus on optimizing the opening dimensions and tapered portion geometry for better coating adhesiveness without compromising hole formation precision.
2Stability of the object's composition
If the tapered portion is made thick and steep to maintain structural integrity, then the insulating films remain stable, but the upper layer cannot coat the inner side of the hole sufficiently, increasing contact resistance
Solution Approach 1:
The patent changes the geometric parameters of the tapered portion by controlling the etching conditions in two steps. The first etching step creates a tapered portion with specific angle and thickness, while the second step adjusts the opening dimensions. This parameter optimization allows the upper layer to coat the inner side of the hole sufficiently, reducing contact resistance while maintaining insulating film stability.
3Area of moving object
If the hole size is reduced to improve device density, then more components can be packed, but the coating quality and adhesiveness deteriorate due to the steep tapered portions
Solution Approach 1:
By segmenting the etching process into two steps, the patent can independently control the hole depth (for small size) and the opening dimensions (for coating quality). The first step forms the deep narrow hole for high density, while the second step optimizes the opening shape to ensure adequate coating coverage, thus resolving the contradiction between hole size reduction and coating quality maintenance.
4Adaptability or versatility
If multiple insulating films with different materials are used to achieve complex functions, then device functionality increases, but the etching process becomes more complex requiring different etching gases
Solution Approach 1:
The patent changes etching parameters including gas composition and process conditions between the two etching steps to selectively etch different insulating film materials. The first etching step uses parameters optimized for etching through the first insulating film, while the second step uses different parameters for enlarging the hole opening through subsequent films. This parameter adjustment enables handling of multiple materials without requiring fundamentally different process approaches, thus managing complexity while maintaining versatility.
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
The substrate achieves excellent coating quality and adhesiveness of the upper layer within the hole region, reducing contact resistance and preventing corrosion and film peeling, while allowing for smaller hole sizes and improved substrate performance.
Implementation Method 1
a first etching step including dry-etching a pre-treated substrate including an insulating substrate, a lower layer stacked on the insulating substrate, a first insulating film stacked on the lower layer, and a second insulating film stacked on the first insulating film through a mask provided with an aperture to form a hole reaching at least one of the lower layer or the insulating substrate through at least the first insulating film and the second insulating film
Data Source
AI summary
A substrate of the present invention sequentially includes an insulating substrate, a lower layer, a first insulating film, a second insulating film, and an upper layer. The substrate is provided with a hole reaching at least one of the lower layer or the insulating substrate through at least the first insulating film and the second insulating film. The first insulating film includes in a region with the hole a protrusion that protrudes from an end portion in contact with the first insulating film of the second insulating film. The substrate includes a stepwise structure including the protrusion and the end portion. The upper layer coats the stepwise structure. An upper surface portion of the first insulating film in a region with the protrusion and an upper surface portion of the first insulating film in a region below the end portion of the second insulating film are coplanar.