PLS Display Substrate Reducing Mask Count to Four
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing manufacturing process for liquid crystal display devices in the Plane to Line Switching (PLS) mode requires five masks, which increases production costs and complexity, making it difficult to reduce the number of process steps effectively.
Innovation Solution
The process is optimized by reducing the number of masks from five to four by entirely depositing and patterning a lower common electrode, using a Si-based insulating layer, and selectively patterning gate and source/drain electrodes with fewer masks, thereby simplifying the photolithography process and reducing defects from static electricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If five mask processes are used to fabricate the display substrate, then the manufacturing precision and pattern definition are improved, but the production cost and process complexity increase
Solution Approach 1:
The patent merges the patterning of the lower common electrode with the gate electrode patterning by using a single mask for both features. This is achieved by designing the mask pattern to define both the lower common electrode regions and the gate electrode regions simultaneously, thereby reducing the total mask count from five to four while maintaining manufacturing precision
Solution Approach 2:
The patent makes one mask serve multiple functions by using it to define both the lower common electrode and the gate electrode patterns. This multi-functional mask approach allows a single masking step to accomplish what previously required separate masking steps, reducing process complexity without sacrificing pattern definition quality
2Manufacturing precision
If five mask processes are used to fabricate the display substrate, then the pattern definition accuracy is improved, but the productivity decreases
Solution Approach 1:
The patent combines multiple patterning operations into fewer mask steps by using a single mask to define both the lower common electrode and gate electrode. This reduction from five mask processes to four directly improves productivity by decreasing the number of sequential steps required while preserving pattern definition accuracy through careful mask design
3Ease of manufacture
If multiple thin films are patterned by using one mask, then the mask usage cost is reduced, but the etching process complexity increases due to different etching methods required
Solution Approach 1:
The patent applies local quality by using different etching methods for different regions patterned by the same mask. Specifically, the lower common electrode is patterned using wet etching while the gate electrode is patterned using dry etching, allowing each material to be etched with its optimal method while still using a single mask for both patterning operations
Data Source
AI summary
Disclosed are a display substrate, of which productivity is improved by decreasing five mask (M) processes utilized for fabricating the display substrate used in a liquid crystal display device in a horizontal field (Plane to Line Switching (PLS)) mode to four mask processes, and a method of fabricating the same.