Recess Etching with Sidewall Protection for Deep Feature Precision
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Solution Overview
Problem
Existing substrate processing methods face challenges in forming precise and deep recesses in etching target films without causing shape defects, particularly in high aspect ratio features, due to uneven etching of the side and bottom walls.
Innovation Solution
A method involving the formation of a first layer containing nitrogen and hydrogen atoms on the side wall of a recess using a specific process gas, followed by a second layer formed from a phosphorus-containing gas, and then etching the recess using a third process gas, which suppresses side wall etching and allows for controlled depth achievement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional etching methods are used to form deep recesses, then the recess depth can be increased, but shape defects occur due to uneven etching of side and bottom walls
Solution Approach 1:
The patent applies local quality by forming a protective film selectively on the side walls of the recess using nitrogen-containing and phosphorus-containing gases. This creates different protective properties in different locations: the side walls have a protective film that prevents etching, while the bottom wall remains exposed for etching. This resolves the contradiction by enabling deep recess formation while maintaining shape uniformity through localized protective treatment.
Solution Approach 2:
The patent employs preliminary action by forming the protective film on the side walls before performing the etching process. This advance preparation ensures that when etching occurs, the side walls are already protected while the bottom wall is ready for controlled removal. This sequence prevents shape defects from the outset while achieving the desired recess depth.
2Manufacturing precision
If etching is performed to achieve precise feature formation, then manufacturing precision improves, but side wall integrity deteriorates due to unwanted etching
Solution Approach 1:
The protective film formed with nitrogen and phosphorus-containing gases provides localized protection specifically on the side walls during etching. This allows precise etching of the bottom wall to achieve feature precision while the side walls remain intact due to the protective film, thereby maintaining side wall integrity throughout the process.
Solution Approach 2:
The protective film acts as an intermediary substance between the etching process and the side walls. It mediates the interaction by allowing the etching gas to selectively remove material from the bottom wall while blocking the side walls from etching damage. This intermediary layer enables precise feature formation without compromising side wall integrity.
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 deep recesses with reduced shape defects by selectively etching the bottom of the recess while maintaining the integrity of the side walls, ensuring precise feature formation.
Implementation Method 1
forming a first layer containing a nitrogen atom and a hydrogen atom on a side wall of a recess formed in the etching target film corresponding to the opening, using a first process gas
Implementation Method 2
forming a second layer from the first layer, using a second process gas containing a phosphorus-containing gas
Implementation Method 3
etching the recess using a third process gas
Data Source
AI summary
A method of processing a substrate including an etching target film and a mask provided on the etching target film and having an opening, may include: (a) forming a first layer containing a nitrogen atom and a hydrogen atom on a side wall of a recess formed in the etching target film corresponding to the opening, using a first process gas; (b) forming a second layer from the first layer, using a second process gas containing a phosphorus-containing gas; and (c) etching the recess using a third process gas.