Silicon Layer Etching via Denatured Oxide Film Removal
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Solution Overview
Problem
Current methods for etching silicon layers in electronic device manufacturing require multiple steps and low throughput due to the need to separately remove natural oxide films and denatured regions, increasing the risk of damage to the silicon layer and mask.
Innovation Solution
A method involving the formation of a denatured region using a plasma of hydrogen, nitrogen, and fluorine, followed by removal with a rare gas plasma, and subsequent etching with a second plasma gas within a single processing container, allowing for high-throughput oxide film removal without changing the gas species and minimizing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate steps are used to remove oxide films and denatured regions, then the oxide film removal is thorough, but the processing time increases and throughput decreases
Solution Approach 1:
The patent combines multiple separate processing steps (oxide film removal and denatured region removal) into a single integrated plasma processing step. By using a plasma process that simultaneously removes both the oxide film and the denatured region formed during etching, the invention eliminates the need for separate processing steps, thereby increasing throughput while maintaining complete removal effectiveness.
Solution Approach 2:
The plasma processing method described in the patent performs multiple functions simultaneously: it removes oxide films, removes denatured regions formed during etching, and prepares the surface for subsequent processing. This multi-functional approach allows a single processing step to achieve what previously required multiple separate steps, improving productivity without sacrificing removal completeness.
2Reliability
If multiple separate steps are used for oxide film removal, then the removal is complete, but the number of processing steps increases and complexity increases
Solution Approach 1:
The patent merges multiple processing steps into a single plasma processing operation that simultaneously removes oxide films and denatured regions. This consolidation reduces the number of processing steps and simplifies the overall process flow while maintaining complete removal effectiveness, directly addressing the contradiction between removal completeness and process complexity.
3Productivity
If conventional plasma etching is used on oxide films, then the etching can be performed, but the mask and silicon layer may be damaged
Solution Approach 1:
The patent applies a preliminary plasma treatment step that modifies the oxide film and denatured region before the main etching process. This preliminary action prepares the surface by removing contaminants and modifying the chemical composition, allowing subsequent etching to proceed more efficiently with reduced risk of damage to the underlying silicon layer and mask structures.
Solution Approach 2:
The invention employs specific plasma parameters (gas composition, power levels, pressure conditions) that are optimized to remove oxide films and denatured regions without causing excessive damage to the silicon layer and mask. By carefully controlling plasma parameters, the process achieves effective removal while minimizing harmful effects on sensitive structures.
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 efficient and high-throughput oxide film removal and etching of silicon layers, reducing the risk of damage to the silicon layer and mask, and simplifying the process by performing these steps in a single container.
Implementation Method 1
forming a denatured region by generating plasma of a first processing gas containing hydrogen, nitrogen, and fluorine within a processing container accommodating the workpiece therein to denature an oxide film formed on a surface of the workpiece
Implementation Method 2
silicon oxide forming the oxide film is denatured to (NH4)2SiF6, i.e., ammonium fluorosilicate, thereby forming a denatured region
Implementation Method 3
removing the denatured region by generating plasma of a rare gas within the processing container
Implementation Method 4
etching the silicon layer generating plasma of a second processing gas within the processing container
Data Source
AI summary
Disclosed is a method of etching a silicon layer by removing an oxide film formed on a workpiece which includes the silicon layer and a mask provided on the silicon layer. The method includes: (a) forming a denatured region by generating plasma of a first processing gas containing hydrogen, nitrogen, and fluorine within a processing container accommodating the workpiece therein to denature an oxide film formed on a surface of the workpiece; (b1) removing the denatured region by generating plasma of a rare gas within the processing container; and (c) etching the silicon layer by generating plasma of a second processing gas within the processing container.