Laser Ablation for TFT Pixel Structure Fabrication
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Solution Overview
Problem
The conventional method for fabricating pixel structures in TFT-LCDs requires multiple expensive photolithography and etching processes, leading to high fabrication costs, especially as the size of the panels increases, due to the need for various photo-masks and complex processes.
Innovation Solution
The method employs a laser ablation process using shadow masks to form each film layer of the pixel structure, reducing the need for expensive photolithography and etching processes and simplifying the fabrication steps, with the laser beam's energy and position adjusted digitally for precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple photolithography and etching processes are used to fabricate pixel structures, then manufacturing precision is improved, but fabrication cost increases
Solution Approach 1:
The patent replaces the conventional photolithography and etching processes with a laser ablation process. The laser beam systematically removes material layer by layer to form pixel structures, eliminating the need for multiple photo-masks and chemical etching steps. This substitution of mechanical/chemical processes with a laser-based process reduces fabrication cost while maintaining manufacturing precision.
Solution Approach 2:
The patent changes the processing parameters from conventional photolithography (using photo-masks, photoresist, and chemical etchants) to laser ablation (using laser beam parameters such as power, pulse duration, and scanning speed). By adjusting laser parameters, the same manufacturing precision can be achieved without the need for expensive multiple photo-masks and complex chemical processes.
2Area of stationary object
If the size of TFT-LCD panel is increased, then display area is improved, but fabrication cost increases due to larger photo-masks
Solution Approach 1:
The laser ablation process eliminates the need for large physical photo-masks required in conventional photolithography for large panels. The laser beam can be digitally controlled to pattern large areas without requiring proportionally larger and more expensive photo-masks, thus reducing the cost increase associated with larger display areas.
Solution Approach 2:
The laser ablation system serves multiple functions: it can pattern different pixel structures, adjust to different panel sizes, and modify patterns through digital control without requiring physical mask changes. This universality allows the same equipment and process to efficiently manufacture various panel sizes without proportionally increasing fabrication cost.
3Manufacturing precision
If multiple photo-masks are used for different patterns, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces the complex sequence of multiple photolithography and etching processes with a single laser ablation process. The laser system with digital control can sequentially or simultaneously create different patterns without requiring multiple photo-masks, alignment steps, and chemical processing stages, thereby reducing fabrication process complexity while maintaining pattern precision.
Solution Approach 2:
The patent extracts and removes the unnecessary photo-masks and photoresist steps from the fabrication process. By using laser ablation directly on the deposited layers, the process eliminates intermediate materials and steps, simplifying the overall fabrication process while maintaining the ability to create precise patterns.
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 significantly lowers the fabrication cost by eliminating the need for multiple photo-masks and complex processes, reducing defects, and allowing for more efficient production with the ability to repair pixel structures, such as fixing short circuits, thereby improving production yield.
Implementation Method 1
the first conductive layer is irradiated by a laser beam through the first shadow mask, so as to remove the portion of the first conductive layer exposed by the first shadow mask to form a gate electrode
Implementation Method 2
The semiconductor layer is irradiated by a laser beam through the second shadow mask, so as to remove the portion of the semiconductor layer exposed by the second shadow mask to form a channel layer
Data Source
AI summary
A method for fabricating a pixel structure using a laser ablation process is provided. This fabrication method forms a gate, a channel layer, a source, a drain, a passivation layer, and a pixel electrode sequentially by using a laser ablation process. Particularly, the fabrication method is not similar to a photolithography and etching process, so as to reduce the complicated photolithography and etching processes, such as spin coating process, soft-bake, hard-bake, exposure, developing, etching, and stripping. Therefore, the fabrication method simplifies the process and thus reduces the fabrication cost.