Etch Stopper Layer Patterning for LCD Fabrication
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Solution Overview
Problem
The existing methods for fabricating liquid crystal display (LCD) devices require a complex and costly process due to the use of multiple masks, which leads to plasma damage during etching, affecting TFT characteristics and increasing fabrication costs.
Innovation Solution
A method that forms a gate electrode on a substrate, followed by sequential layers of insulation, semiconductor, and etch stopper, patterning the etch stopper and semiconductor layers without additional masking, forming conductive layers for source and drain electrodes, and using a contact hole to connect the pixel electrode, all while eliminating the need for additional masking processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional masking processes are used to form etch stopper patterns, then etching precision is improved, but device complexity and fabrication cost increase
Solution Approach 1:
The patent combines the etch stopper layer formation with the semiconductor layer patterning process by using the same mask pattern for both layers. This merging of processes eliminates the need for separate masking steps while maintaining precise etching, directly resolving the contradiction between etching precision and process complexity
Solution Approach 2:
The etch stopper layer is formed with predetermined patterns during the semiconductor layer patterning process, preparing the structure in advance for subsequent etching steps. This preliminary action ensures precise etching boundaries are already established before the actual etching occurs, eliminating the need for additional masking
2Manufacturing precision
If multiple masking processes are used, then pattern precision is improved, but productivity decreases
Solution Approach 1:
The patent merges multiple patterning operations into a single masking process, where one mask simultaneously defines both the semiconductor layer pattern and the etch stopper layer pattern. This reduction in the number of masking steps directly improves productivity while preserving pattern precision through careful mask design
Solution Approach 2:
The mask used in the patent serves multiple functions: it patterns the semiconductor layer, patterns the etch stopper layer, and defines the channel region boundaries. This multi-functionality of the mask reduces the total number of masking steps required, thereby improving fabrication productivity without sacrificing pattern precision
3Productivity
If plasma etching is used for source and drain electrode formation, then manufacturing efficiency is improved, but harmful plasma damage occurs to the channel region
Solution Approach 1:
The etch stopper layer acts as an intermediary protective layer between the plasma etching process and the channel region. It absorbs or blocks harmful plasma effects while allowing the efficient plasma etching process to continue, thus protecting the channel region from damage while maintaining manufacturing efficiency
Solution Approach 2:
The etch stopper layer is formed beforehand to provide a protective barrier that cushions the channel region against plasma damage. This prior cushioning ensures that when plasma etching is performed for source and drain electrode formation, the channel region is already protected from harmful effects
Data Source
AI summary
A method for fabricating a liquid crystal display includes: forming a gate electrode on a substrate; sequentially providing an insulation layer, a semiconductor layer and an etch stopper layer on the gate electrode; patterning the etch stopper layer and the semiconductor layer to form an etch stopper layer pattern and a semiconductor layer pattern; removing both side portions of the etch stopper layer pattern to expose the lower semiconductor layer pattern portion; forming a conductive layer on an entire surface of the substrate; patterning the conductive layer to form source and drain electrodes and defining a channel region; forming a passivation layer having a contact part on the entire surface of the substrate; and forming a pixel electrode connected with the drain electrode via the contact part on the passivation layer. An etch stopper can be used without additionally performing a masking process.