Mask Partial-Transparent Area Prevents Thin Film Fragmentation
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Solution Overview
Problem
The existing array lithography process in liquid crystal display manufacturing faces challenges with photoresist thickness, leading to high costs with thick photoresist and a higher risk of defects with thin photoresist, resulting in fragmented thin films and indium tin oxide (ITO) layers around through holes due to steep slopes after etching.
Innovation Solution
A mask with a light-blocking area, a transparent area, and a partial-transparent area that protrudes from the edges of the light-blocking area, allowing controlled UV transmission, is used in conjunction with a metallic sheet and organic film to achieve a gradual transition in transparency, preventing fragmentation of thin films and ITO layers during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thicker photoresist is used, then photoresist strength is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies local quality by creating a partial-transparent area with specific transmission rate (10%-90%) at the edge region of the mask, while the central light-blocking area maintains complete opacity. This localized transparency control allows differential UV exposure that forms photoresist with optimal thickness distribution - thicker at edges for strength, thinner at center for cost efficiency - resolving the contradiction between photoresist strength and manufacturing cost.
2Ease of manufacture
If thinner photoresist is used, then manufacturing cost is reduced, but reliability deteriorates due to film breakage
Solution Approach 1:
The partial-transparent area creates a gradient UV exposure zone that forms photoresist with locally optimized thickness. The edge regions receive partial UV transmission forming thicker, more reliable photoresist layers that prevent film breakage, while central regions use thinner photoresist for cost reduction. This spatially varying photoresist thickness distribution resolves the contradiction between manufacturing cost and film integrity.
3Measurement precision
If conventional mask with sharp edges is used, then lithography precision is improved, but manufacturing precision deteriorates due to film fragmentation around through holes
Solution Approach 1:
The partial-transparent area at the mask edge creates a gradual UV exposure transition zone that forms photoresist with gradient thickness and small-angle edges. This gradient structure prevents sharp stress concentrations that cause film fragmentation during etching, while the central light-blocking area maintains precise lithography patterns. The engaging frame structure further supports the organic film to prevent deformation, resolving the contradiction between lithography precision and film formation quality.
Solution Approach 2:
The organic film with partial-transparent area serves as a beforehand cushioning structure that pre-forms gradient photoresist thickness and small-angle edges before the etching process. This preparatory gradient structure cushions against the stress concentrations that would otherwise cause film fragmentation during subsequent etching, preventing manufacturing defects before they occur.
4Manufacturing precision
If mask with partial-transparent area is used, then film fragmentation is prevented, but device complexity increases
Solution Approach 1:
The mask structure implements complexity only where needed - the partial-transparent area is localized to the edge region (protruding from light-blocking area edges) with specific transmission rate (10%-90%), while the central light-blocking area maintains simple complete opacity. The organic film coating is also localized to edge regions. This localized complexity approach prevents film fragmentation at critical edge zones while maintaining simple mask structure elsewhere, resolving the contradiction between film formation quality and overall device complexity.
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 solution results in the formation of thin film edges with small angles, reducing the defective rate by preventing fragmentation and improving the quality of the thin film and ITO layer around through holes, thereby enhancing the manufacturing process efficiency and reducing costs.
Implementation Method 1
the partial-transparent area protrudes from edges of the light-blocking area to admit some of the UV rays to pass through
Data Source
AI summary
A manufacturing method of a glass substrate is provided, in which a mask including a light-blocking area, a transparent area and a partial-transparent area is adopted. The partial-transparent area protrudes from edges of the light-blocking area to admit some of the UV rays to pass through. In addition, a glass substrate manufactured with the method is also disclosed. By arranging the partial-transparent area on the edges of the light-blocking area, the mask is formed with a slope having a small angle after a lithography process. As such, in an etching process, an edge of a thin film is formed with a slope having a small angle, which contributes to the formation of a second thin film. The thin films are prevented from being fragmented around the slope and the ITO layer is also prevented from fragmented around the periphery of the through hole.