Alkaline Silicon Etchant Composition for Selective Oxide-Safe Patterning
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Solution Overview
Problem
Existing silicon etchants fail to provide high selectivity and uniformity in etching silicon and silicon oxide films, leading to non-uniform etched surfaces and potential damage to the silicon oxide film.
Innovation Solution
A silicon etchant composition comprising an alkaline compound, a metal salt, and water, which enhances etching performance while providing anticorrosive effects on silicon oxide, ensuring high selectivity and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an acid-based etchant composition is used, then the etching mechanism can oxidize silicon and remove it with fluoride, but the silicon oxide film is damaged and selectivity is reduced
Solution Approach 1:
The patent inverts the conventional acid-based etching mechanism by using an alkaline-based etchant composition. Instead of oxidizing silicon and removing it with fluoride, the alkaline etchant directly attacks silicon through a different chemical mechanism while leaving silicon oxide intact, thereby achieving both high etch rate and high selectivity
Solution Approach 2:
The patent changes the fundamental chemical parameter of the etchant from acidic to alkaline. This parameter change fundamentally alters the etching mechanism and selectivity characteristics, enabling the etchant to differentiate between silicon and silicon oxide films effectively
2Speed
If conventional etchants are used, then silicon can be etched, but the etched surface uniformity is poor
Solution Approach 1:
The patent uses a composite etchant composition containing multiple alkaline compounds (such as ammonium hydroxide and tetramethylammonium hydroxide) along with metal salts. This composite formulation synergistically improves both etch rate and surface uniformity by combining the effects of different chemical components
Solution Approach 2:
The patent introduces metal salts as intermediaries in the etching process. These metal salts act as catalysts or mediators that enhance the etching reaction uniformity across the silicon surface, leading to more consistent etch rates and improved surface uniformity
3Reliability
If high selectivity is achieved, then the silicon oxide film is protected, but the etching time may increase
Solution Approach 1:
The patent changes the chemical parameters of the etchant to alkaline conditions, which enables simultaneous achievement of high selectivity and high etch rate. The alkaline environment provides both protection for silicon oxide and efficient removal of silicon, eliminating the trade-off between selectivity and etching time
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 etchant composition achieves a fast etch rate for silicon with improved selectivity and uniformity, minimizing damage to the silicon oxide film and enhancing the reliability of semiconductor elements.
Implementation Method 1
The wet etching process is a method of etching using a chemical etchant, and is performed by immersing an object to be removed in an etchant
Implementation Method 2
capable of securing an anticorrosive effect of silicon oxide while maintaining etching performance of silicon
Data Source
AI summary
The present disclosure relates to a silicon etchant composition comprising (A) an alkaline compound, (B) a metal salt, and (C) water, a pattern formation method and a manufacturing method of an array substrate using the silicon etchant composition, and an array substrate manufactured therefrom.