Fluorocarbon Gas Plasma Etching High Aspect Ratio Holes
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Solution Overview
Problem
In semiconductor manufacturing, plasma etching methods struggle to achieve precise control of vertical processing shapes, particularly for holes with large aspect ratios, while maintaining a high etching rate and selectivity at low plasma application power.
Innovation Solution
A plasma etching method using a fluorocarbon gas with a benzene ring structure, represented by CxFy where x≥7 and y≥x, which is more stable and likely to ionize, increasing the etching rate and selectivity with respect to the etching mask, even at low plasma application power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If conventional plasma etching methods are used, then etching can be performed on silicon-containing films, but the etching rate is low and selectivity with respect to etching masks deteriorates when plasma application power is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the process gas from conventional gases (CF4, SF6, C4F8) to a specific fluorocarbon gas with formula CxFy where x≥7 and y≥x. This parameter change in gas composition enables high etching rate and selectivity even at reduced plasma power levels, resolving the contradiction between low power consumption and high productivity.
2Manufacturing precision
If conventional plasma etching methods are used, then etching can be performed, but precise control of vertical processing shapes is difficult for holes with large aspect ratios
Solution Approach 1:
The patent applies parameter changes by introducing a fluorocarbon gas with specific molecular characteristics (x≥7, y≥x) that inherently provides better anisotropic etching properties. This enables precise vertical shape control for high aspect ratio holes without requiring complex process control systems, thus improving manufacturing precision without increasing device complexity.
3Reliability
If conventional fluorocarbon gases are used, then etching can be performed, but processing selectivity with respect to etching masks is insufficient
Solution Approach 1:
The patent changes the gas composition parameters by using fluorocarbon gas with specific stoichiometric ratios (y≥x where x≥7). This composition parameter change enhances the gas's ability to provide selective etching with respect to etching masks, improving reliability in the etching process.
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 enhances the etching rate and processing selectivity for silicon-containing films, enabling the formation of holes with large aspect ratios at reduced plasma power, while selectively processing silicon-containing films over metal films.
Implementation Method 1
a fluorocarbon gas with a benzene ring structure, represented by CxFy where x≥7 and y≥x, which is more stable and likely to ionize, increasing the etching rate and selectivity
Implementation Method 2
performing etching on a silicon-containing film by using plasma of a fluorocarbon gas
Data Source
AI summary
A plasma etching method of an embodiment includes performing etching on a silicon-containing film by using plasma of a fluorocarbon gas. The fluorocarbon gas used in the plasma etching method has a composition, regarding carbon and fluorine, represented by CxFy, wherein x and y are numbers satisfying x≥7 and y≥x, and includes a benzene ring structure composed of six carbon atoms.