Liquid Crystal Display Source Drain Electrode Over-etching Prevention
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Solution Overview
Problem
The existing methods for manufacturing liquid crystal display (LCD) devices suffer from over-etching issues during the wet-etching process, which leads to degraded thin film transistor properties and display quality due to increased channel length and electrode width deviations.
Innovation Solution
A method involving plasma treatment and a copper compound removing solution is employed to form source and drain electrodes with precise dimensions, avoiding over-etching and maintaining the desired channel length, thereby improving the thin film transistor properties and display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wet-etching process is used to form source and drain electrodes, then the etching process is simple and fast, but over-etching occurs leading to increased channel length and degraded transistor properties
Solution Approach 1:
A copper oxide film is introduced as an intermediary layer between the copper group material layer and the wet-etching solution. This film acts as a protective barrier that prevents the etching solution from directly contacting and over-etching the source and drain electrode patterns, thereby maintaining precise channel length while allowing the wet-etching process to proceed efficiently.
Solution Approach 2:
The copper oxide film is formed in advance through plasma treatment or oxidation process before the wet-etching step. This preliminary formation of the protective film ensures that when the wet-etching solution is subsequently applied, the electrode patterns are already protected, preventing over-etching and maintaining manufacturing precision without sacrificing productivity.
2Ease of manufacture
If photoresist patterns are used as etching masks, then the patterning process is straightforward, but the etching solution flows below the photoresist patterns causing over-etching
Solution Approach 1:
The copper oxide film serves as an intermediary protective layer between the photoresist pattern and the wet-etching solution. This film prevents the etching solution from flowing underneath the photoresist and attacking the electrode patterns, thereby maintaining both the simplicity of the patterning process and the precision of electrode dimensions.
3Area of stationary object
If the channel length increases due to over-etching, then the transistor coverage area increases, but the thin film transistor properties are degraded
Solution Approach 1:
The potential harm of over-etching is converted into a beneficial protective mechanism. The copper oxide film, which would normally be considered an unwanted oxidation byproduct, is intentionally formed and utilized as a protective layer that prevents harmful over-etching, thereby preserving transistor performance while maintaining the desired channel dimensions.
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 ensures accurate electrode formation, maintaining the designed channel length and enhancing the display quality by preventing over-etching and maintaining precise electrode dimensions, thus improving the overall performance of the LCD device.
Implementation Method 1
performing a plasma treatment for the copper group material layer using the first and second photoresist patterns as a reaction mask, whereby portions of the copper group material layer between the first and second photoresist patterns are changed into a copper compound
Implementation Method 2
deoxidizing or removing the copper oxide film
Data Source
AI summary
A method of manufacturing a liquid crystal display device is provided which includes ashing first and second photoresist patterns, whereby a copper oxide film is formed at portions of a data line and a source-drain pattern exposed between the ashed first and second photoresist patterns and between the ashed first and second portions of the first photoresist pattern; deoxidizing or removing the copper oxide film; performing a plasma treatment to change the exposed portions of the data line and the source-drain pattern into a copper compound; removing the copper compound using a copper compound removing solution to form source and drain electrodes below the ashed first and second portions, respectively, wherein the copper compound removing solution substantially has no reaction with the copper group material; dry-etching a portion of an ohmic contact layer between the source and drain electrodes using the source and drain electrodes as an etching mask, the ohmic contact layer formed by patterning the impurity-doped amorphous silicon layer.