Substrate Etching Sequence Using By-Product Saturation Adsorption
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Solution Overview
Problem
Existing substrate processing methods face challenges in achieving controlled etching of films containing group XIV elements, such as silicon, due to limitations in reaction by-product management and adsorption saturation.
Innovation Solution
A technique involving the sequential supply of a first gas containing a group XIV element to saturate and adsorb reaction by-products on the substrate, followed by a second gas containing a halogen, and alternating between these steps to etch the film effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a precursor gas including silane-based gas, chlorine-based or fluorine-based gas, and hydrogen-based gas are sequentially and repeatedly supplied to grow a film on silicon layer, then film growth is achieved, but etching controllability deteriorates
Solution Approach 1:
The gas supply process is segmented into distinct phases: a film growth phase using precursor gases (silane, chlorine, fluorine, hydrogen) and a by-product removal phase using a nitrogen-containing gas. This segmentation allows independent optimization of each phase, achieving precise etching control by clearly separating the film formation and etching functions in time and gas composition.
Solution Approach 2:
The method employs periodic alternation between film growth gas supply and nitrogen-containing gas supply. By repeatedly cycling between these two gas supply modes, the process achieves controlled etching through periodic removal of reaction by-products, enabling precise control over film thickness and etching depth while maintaining process simplicity.
2Manufacturing precision
If reaction by-products are not removed from substrate surface, then film growth continues, but etching selectivity deteriorates
Solution Approach 1:
A nitrogen-containing gas is introduced as an intermediary substance to mediate between film growth and etching processes. This gas specifically adsorbs reaction by-products on the substrate surface without reacting with the film material itself, enabling selective removal of by-products while preserving the film, thus achieving high etching selectivity with minimal material loss.
Solution Approach 2:
The method changes the chemical composition parameter of the gas phase by switching from precursor gases to nitrogen-containing gas. This parameter change alters the surface chemistry environment, enabling selective adsorption of by-products while maintaining film integrity, thereby achieving precise control over etching selectivity and minimizing unwanted material loss.
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 method enhances the controllability of etching processes, improves etching selectivity, and maintains high in-plane uniformity, thereby supporting precise micro-fabrication of group XIV element-containing films.
Implementation Method 1
supplying a first gas containing a group XIV element to a substrate on which a film containing the group XIV element is formed such that reaction by-products generated by reaction with the group XIV element contained in the film formed on the substrate are saturated and adsorbed on the substrate
Implementation Method 2
supplying a second gas containing a halogen after (a); and (c) etching the film containing the group XIV element formed on the substrate by alternately repeating (a) and (b)
Data Source
AI summary
There is provided a technique that includes: (a) supplying a first gas containing a group XIV element to a substrate on which a film containing the group XIV element is formed such that reaction by-products generated by reaction with the group XIV element contained in the film formed on the substrate are saturated and adsorbed on the substrate; (b) supplying a second gas containing a halogen after (a); and (c) etching the film containing the group XIV element formed on the substrate by alternately repeating (a) and (b).