Plasma Etching Using C2F4 Gas for High-Perpendicularity Holes
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Solution Overview
Problem
In semiconductor device fabrication, high-aspect-ratio insulating films require etching gases containing carbon and fluorine to form grooves with high perpendicularity, but existing methods struggle to maintain groove integrity and perpendicularity due to the etching process.
Innovation Solution
A plasma etching method using a gas mixture of C2F4, where the emission intensity of CF2 radicals is set to be equal to or more than 3.5 times that of C2 radicals, generating plasma to form high-perpendicularity holes by controlling the device conditions and emission intensity ratios within a plasma processing device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a gas containing carbon and fluorine is used as etching gas for high-aspect-ratio insulating films, then groove perpendicularity is improved, but mask closure occurs and groove integrity deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the etching gas by specifying a gas containing C2F4 (tetrafluoroethylene) and controlling the emission intensity ratio of CF2 to C2 to be 3.5 times or more. This parameter change enables simultaneous achievement of high groove perpendicularity and prevention of mask closure, resolving the technical contradiction between groove shape quality and process reliability.
Solution Approach 2:
The patent introduces feedback control by monitoring the emission intensity ratio of CF2 to C2 radicals during plasma etching and adjusting process conditions to maintain the ratio at 3.5 times or more. This feedback mechanism ensures optimal etching performance while preventing mask closure, thereby maintaining groove integrity throughout the etching process.
2Manufacturing precision
If emission intensity of CF2 is increased to maintain groove perpendicularity, then etching selectivity is improved, but process control complexity increases
Solution Approach 1:
The patent simplifies process control by establishing a specific parameter target: maintaining the emission intensity ratio of CF2 to C2 at 3.5 times or more. This clear parameter specification provides straightforward guidance for process control while achieving high etching selectivity, avoiding the need for complex multi-parameter optimization.
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 ensures the formation of high-perpendicularity holes in the workpiece film by maintaining a constant Bowing Critical Dimension (BCD) and preventing mask closure, thereby enhancing the etching process's selectivity and groove integrity.
Implementation Method 1
generating plasma to form high-perpendicularity holes by controlling the device conditions and emission intensity ratios within a plasma processing device
Data Source
AI summary
A plasma etching method includes performing a plasma etching using a gas containing C2F4. An emission intensity of CF2 is equal to or more than 3.5 times an emission intensity of C2 while generating plasma.