Thin Film Patterning via Multi-Layer Masking for Micron Resolution
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Solution Overview
Problem
Current methods for forming thin film patterns in flat display devices struggle to achieve resolutions below the minimum line width and distance due to limitations in photoresist pattern formation and etching processes, making it difficult to fabricate micron-scale patterns.
Innovation Solution
A method involving the sequential formation of three thin film layers, where the second layer is an inorganic insulating film or columnar crystal material and the third layer is a non-transparent material that shields light, allowing for the creation of thin film mask patterns with varying line widths and taper angles, and subsequent photoresist patterning to achieve precise thin film patterns with line widths of 400-1000 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography and etching processes are used, then the manufacturing process is simple, but the minimum line width and distance are limited to about 3-4 μm, making it difficult to form micron-scale patterns
Solution Approach 1:
The fabrication process is divided into multiple sequential steps: forming three thin film layers (first thin film layer, second thin film layer, third thin film layer), creating first photoresist pattern, patterning second and third thin film layers to form first and second thin film mask patterns, forming second photoresist pattern, removing mask patterns, and patterning first thin film layer. This segmentation enables achieving line widths of 400-1000 nm by breaking down the complex patterning task into manageable stages, each contributing to the final high-resolution pattern.
Solution Approach 2:
The second thin film layer is prepared in advance as a mask layer with specific material properties (inorganic insulating film or columnar crystal group material) that enable controlled etching. The third thin film layer is also formed beforehand as a non-transparent shielding layer. These preliminary preparations of functional layers with specific properties allow the subsequent photolithography and etching steps to achieve micron-scale precision that would be impossible with conventional single-step processes.
2Manufacturing precision
If the photoresist pattern minimum line width is about 4 μm, then the photoresist fabrication is straightforward, but the resulting thin film pattern resolution cannot achieve below 3 μm line width
Solution Approach 1:
The second thin film layer serves as an intermediary mask layer between the photoresist pattern and the first thin film layer to be patterned. This intermediate mask layer, formed by etching the second thin film layer using the photoresist pattern, enables the transfer of patterns at a different scale. The intermediary mask layer with its specific etching properties allows achieving sub-3 μm resolution in the final pattern even when the photoresist pattern itself has a minimum line width of about 4 μm.
Solution Approach 2:
The invention changes the material parameters and structural parameters of the thin film layers. The second thin film layer uses specific materials (inorganic insulating film or columnar crystal group material) with controlled thickness and etching characteristics. The third thin film layer provides optical shielding with specific thickness. These parameter changes in material composition, thickness, and optical properties enable the system to achieve resolution beyond the limitations of conventional photoresist minimum line widths.
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
Enables the formation of micron-scale patterns with improved resolution, allowing for increased pixel region aperture and application in various flat display devices without the need for separate alignment steps, enhancing the fabrication of thin film transistors and display devices.
Implementation Method 1
the third thin film layer is formed of a non-transparent material which shields a light
Data Source
AI summary
The present disclosure is a method for forming a thin film pattern to form a micron-pattern and a flat display device having the same. The method for forming a thin film pattern includes the steps of forming first to third thin film layers on a substrate in succession, forming a first photoresist pattern on the third thin film layer, patterning the second and third thin film layers using the first photoresist pattern as a mask to form first and second thin film mask pattern having line widths different from each other, forming a second photoresist pattern at a region where the first and second thin film mask patterns do not overlap positioned between the first thin film layer and the second thin film mask pattern, removing the first and second thin film mask patterns, and patterning the first thin film layer using the second photoresist pattern as a mask.