LCD Peripheral Line with Slit Openings for Plasma Control
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Solution Overview
Problem
The existing methods for fabricating liquid crystal display (LCD) devices, such as the five-mask and four-mask processes, often result in over-etching of peripheral lines during the dry-etching process, leading to degraded display quality due to plasma concentration and increased etching times, which affects the resistance and integrity of the peripheral lines.
Innovation Solution
A substrate for LCD devices is fabricated using a four-mask method with a peripheral line that incorporates slit-shaped openings in the non-display region to reduce plasma concentration during dry-etching, thereby preventing over-etching and improving display quality by maintaining uniform resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the peripheral line is formed with a large area to reduce resistance, then the resistance is reduced, but plasma concentration increases causing over-etching
Solution Approach 1:
The peripheral line is divided into multiple segments by forming openings (insulating film removal portions) at regular intervals along its length. This segmentation reduces plasma concentration at any single location during dry-etching, preventing over-etching while maintaining the overall large area needed for low resistance
Solution Approach 2:
The insulating film thickness is made non-uniform: thicker at locations where openings are formed and thinner at other locations. This local variation in film quality allows selective etching control - the thinner regions etch more easily while the thicker regions with openings prevent plasma accumulation, thus preventing over-etching
2Productivity
If the four-mask method is used to reduce process time and cost, then productivity is improved, but over-etching of peripheral lines occurs
Solution Approach 1:
The insulating film is formed with non-uniform thickness in advance, with thicker portions at locations where openings will be formed. This preliminary preparation enables selective etching control during the fourth mask process, allowing the peripheral line to be etched without over-etching even when using the simplified four-mask method
3Manufacturing precision
If multiple mask processes are conducted to pattern each layer separately, then manufacturing precision is improved, but production process time and cost increase
Solution Approach 1:
The peripheral line pattern is combined with the pixel electrode pattern in the fourth mask process. By merging these patterning operations, the number of mask processes is reduced from five to four, improving productivity while the non-uniform insulating film structure ensures the peripheral line is still etched with sufficient precision
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
The use of a four-mask method with slit-shaped openings in the peripheral line area reduces over-etching and enhances the display quality of LCD devices by minimizing plasma concentration and maintaining uniform resistance, thus improving the overall performance of the LCD device.
Implementation Method 1
plasma concentration during dry-etching
Data Source
AI summary
A liquid crystal display device includes a substrate having a display region and a non-display region. In the display region, the gate line and a data line cross to define a pixel region and a thin film transistor is disposed at the crossing portion of the gate and data lines. The thin film transistor includes a gate electrode and source and drain electrodes. A peripheral line having a plurality of openings is disposed in the non-display region. The openings are slits, rectangles, circles, or triangles. The openings relieve plasma during dry-etching of the peripheral line. A pixel electrode is connected to the drain electrode in the pixel region.