Dual-Layer Film Pattern Sag Prevention via Cure Shrinkage
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Solution Overview
Problem
In the manufacturing of display devices, the photolithography process faces challenges in accurately forming patterns with minimal shrinkage and defects, particularly due to differences in cure shrinkage ratios of films used, which can lead to pattern sag and defects during the removal of sacrificial layers.
Innovation Solution
A method involving the sequential formation of films with varying cure shrinkage ratios, where a first film with a lower cure shrinkage ratio is patterned and then a second film with a higher cure shrinkage ratio is added, along with a sacrificial layer, to create patterns that minimize sag and enhance process reliability by controlling shrinkage forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single film is used for patterning, then the process is simple, but pattern sag and defects occur due to uniform shrinkage forces
Solution Approach 1:
The patent divides the single film structure into multiple films with different cure shrinkage ratios. The first film has a lower cure shrinkage ratio and the second film has a higher cure shrinkage ratio, creating segmented shrinkage forces that prevent pattern sag during sacrificial layer removal while maintaining process feasibility.
Solution Approach 2:
The patent changes the physical parameter of cure shrinkage ratio by selecting different materials for the first and second films. The first film uses a material with lower cure shrinkage ratio while the second film uses a material with higher cure shrinkage ratio, creating differential shrinkage forces that counteract gravitational sagging.
2Manufacturing precision
If films with different cure shrinkage ratios are used, then pattern sag is reduced, but the process complexity increases
Solution Approach 1:
The patent segments the film structure into multiple layers with distinct material properties. The first film layer has lower cure shrinkage ratio and the second film layer has higher cure shrinkage ratio, allowing precise control over shrinkage forces during processing while maintaining a manageable multi-layer fabrication process.
Solution Approach 2:
The patent employs composite material structure where the first film and second film are composed of different materials with specific cure shrinkage ratios. This composite approach enables tailored shrinkage characteristics that prevent pattern defects while using commercially available photopolymer materials.
3Force
If the second film with higher cure shrinkage ratio is used, then shrinkage forces are enhanced to prevent sag, but the degree of shrinkage of the second pattern becomes greater than the first pattern
Solution Approach 1:
The patent applies local quality by assigning different cure shrinkage ratios to different film layers based on their specific functions. The first film layer has lower shrinkage for dimensional stability while the second film layer has higher shrinkage to provide sufficient lifting force during sacrificial layer removal, optimizing each layer's properties for its specific role.
Solution Approach 2:
The patent strategically changes the cure shrinkage ratio parameter between film layers. The first film uses a material with lower cure shrinkage ratio to maintain shape, while the second film uses a material with higher cure shrinkage ratio to generate adequate shrinkage force for preventing sag, accepting differential shrinkage as a necessary trade-off.
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 approach reduces the likelihood of pattern sag and defects during the removal of sacrificial layers, improving the accuracy and reliability of the pattern formation process in display device manufacturing.
Implementation Method 1
a first curing step for curing the first film and the second film after forming the second film
Implementation Method 2
the first film having a first cure shrinkage ratio, forming a second film on the first film, the second film having a second cure shrinkage ratio greater than the first cure shrinkage ratio
Data Source
AI summary
A method of forming a pattern part includes forming a first film on a target object, the first film having a first cure shrinkage ratio, forming a second film on the first film, the second film having a second cure shrinkage ratio greater than the first cure shrinkage ratio, and patterning the first film and the second film to form a pattern.