Alkali-Soluble Ga Oxide Protection Layer for Flexible TFTs
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Solution Overview
Problem
The manufacturing of field-effect transistors using silicon thin films is challenging on resin substrates due to high-temperature requirements, and amorphous oxide semiconductors are susceptible to acid, necessitating a protective layer that is both acid-resistant and alkali-soluble to facilitate low-temperature processing and prevent erosion.
Innovation Solution
A method involving the formation of a top contact field-effect transistor with a protection layer made of Ga-containing oxide, which is acid-resistant and alkali-soluble, allowing for pattern exposure and development using an alkaline developing liquid, thereby protecting the active layer and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection layer is provided on the active layer to protect it from acid, then the active layer is protected from erosion, but the manufacturing process becomes more complex and requires additional materials
Solution Approach 1:
The photoresist film serves dual functions: as a protective layer during etching and as a patterning material. By making the photoresist film alkali-soluble, it can be removed after serving its protective function, eliminating the need for separate protective layer materials and simplifying the overall manufacturing process while maintaining active layer protection
Solution Approach 2:
The patent uses an alkali-soluble protective film as an intermediary layer between the acid-sensitive active layer and the etching environment. This intermediary layer allows the active layer to be protected during acid etching while being easily removable afterward through alkali treatment, avoiding permanent addition of complex protective layer structures
2Reliability
If SiO2 layer is used to protect the active layer, then the active layer is protected from acid, but the layer cannot be easily removed and requires additional etching processes
Solution Approach 1:
The patent changes the chemical parameter of the protective film by making it alkali-soluble rather than using conventional acid-resistant materials like SiO2. This parameter change allows the protective film to be easily removed by alkali treatment after serving its protective function, dramatically improving ease of manufacture and eliminating complex removal processes
Solution Approach 2:
Instead of using a material that is resistant to acid and difficult to remove (like SiO2), the patent inverts the approach by using a material that is specifically designed to be soluble in alkali. This inversion allows for easy removal of the protective layer after etching, turning a previously difficult process into a simple treatment step
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 enables the formation of field-effect transistors on flexible substrates with improved ON/OFF ratio and reduced damage to the active layer, facilitating the use in flexible display devices like organic EL devices, while simplifying the manufacturing process and reducing erosion risks.
Implementation Method 1
developing the photoresist film using an alkaline developing liquid to form a resist pattern
Implementation Method 2
the active layer is susceptible to acid. Therefore, by providing an acid-resistant layer on the active layer, the active layer containing the amorphous oxide semiconductor is protected from an acid
Data Source
AI summary
There is provided a method of manufacturing a top contact field-effect transistor including forming a protection layer on an active layer formed in a semiconductor layer forming process, forming a photoresist film on the protection layer and pattern exposing the same in an exposure process, and developing the photoresist film passing through the exposure process using an alkaline developing liquid to form a resist pattern and removing a region exposed by the resist pattern from the protection layer to etch the protection layer in a subsequent development process; a field-effect transistor, and a method of manufacturing a display device.