Phosphorus Protective Layer for Sidewall Etching Control
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Solution Overview
Problem
Current plasma etching methods for silicon-containing layers often result in excessive etching on the side wall surfaces, which can lead to unwanted lateral etching and reduced precision in substrate processing.
Innovation Solution
A method involving the formation of a protective phosphorus-containing layer on the side wall surfaces, followed by etching to increase the depth of recesses, using a combination of precursor and protective layers formed with specific gases and plasma conditions to minimize side wall etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If plasma etching is performed on silicon-containing layers, then etching depth can be increased, but excessive side wall etching occurs reducing precision
Solution Approach 1:
A protective layer containing phosphorus is formed on the side wall surface before the main etching process. This preliminary protective coating prevents the side wall from being etched during the subsequent plasma etching, allowing deep etching to proceed without lateral erosion of the side walls.
Solution Approach 2:
The phosphorus-containing protective layer acts as an intermediary between the plasma etching process and the side wall surface. It selectively protects the side wall while permitting the etching front to advance vertically, mediating between the need for deep etching and side wall preservation.
2Productivity
If conventional plasma etching is used, then processing speed is maintained, but side wall damage occurs
Solution Approach 1:
The protective phosphorus layer is applied in advance to counteract the harmful side wall etching effect. By establishing this protective barrier before the main etching process, the method prevents lateral etching damage while maintaining the vertical etching speed and productivity.
3Device complexity
If no protective layer is formed, then process complexity is reduced, but side wall control is lost
Solution Approach 1:
The method introduces a phosphorus-containing protective layer by changing the chemical composition parameter of the side wall surface. This parameter change creates a selective barrier that controls side wall etching, and the phosphorus layer can be formed using standard plasma deposition techniques with phosphorus-containing gases.
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 effectively reduces side wall etching while allowing for deeper etching of the substrate layers, enhancing the precision and control in substrate processing by protecting the side walls during the etching process.
Implementation Method 1
The protective layer contains phosphorus... effectively reduces side wall etching while allowing for deeper etching of the substrate layers
Implementation Method 2
Plasma etching is used for, for example, silicon-containing layers. Plasma etching of silicon-containing layers uses process gases containing fluorocarbon gases
Data Source
AI summary
A system, apparatus and method enable etching of a layer of a substrate with reduced etching on the surface of a side wall of the layer. The etching method includes forming a protective layer on a surface of the side wall defining a recess in the layer. The protective layer contains phosphorus. The etching method further includes etching the layer in one or more additional cycles so as to increase a depth of the recess after the forming the protective layer.