CF-Based Etching Residue Removal Without Fine Pattern Collapse
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Solution Overview
Problem
Existing methods for removing CF-based deposits after plasma etching in semiconductor manufacturing cause pattern damage or collapse, particularly as they involve plasma-based or chemical processes that are not suitable for fine patterns.
Innovation Solution
A method involving the formation of an oxide layer using oxygen-containing radicals followed by chemical or radical processing to remove the CF-based deposits, utilizing remote plasma to minimize ion damage and pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma-based methods or chemical liquids are used to remove CF-based deposits, then the deposits are removed, but pattern damage or pattern collapse occurs
Solution Approach 1:
The patent changes the chemical state of the CF-based deposit by oxidizing it to CFxOy using oxygen-containing radicals. This parameter change (from CF to CFxOy) transforms the deposit into a form that can be removed by gas-phase chemical processing without causing pattern damage, thus resolving the contradiction between effective removal and pattern integrity
Solution Approach 2:
The patent replaces traditional mechanical or liquid-based removal methods with a gas-phase chemical processing method. By using gas-phase oxidation and subsequent gas-phase removal, the method avoids the harmful effects of liquid chemicals and mechanical stress that cause pattern collapse, while still achieving effective deposit removal
2Productivity
If conventional plasma etching with CF-based gas is used, then oxide film etching is achieved, but CF-based deposit remains as etching residue
Solution Approach 1:
The patent combines the etching process with a subsequent oxidation process in sequence. The oxygen-containing radicals continue the useful action by oxidizing the CF-based deposit formed during etching, transforming it into CFxOy that can be easily removed. This continuous action ensures both high etching efficiency and complete residue removal without interrupting the production flow
3Reliability
If plasma processing is used to remove deposits, then deposits are removed, but ion damage occurs to the pattern
Solution Approach 1:
The patent introduces oxygen-containing radicals as an intermediary substance that mediates the removal process. Instead of using ion-based plasma that directly damages the pattern, the oxygen radicals oxidize the deposit first, and then gas-phase chemical processing removes the oxidized material. This intermediary oxidation step enables effective removal without ion damage to the underlying pattern
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
Effectively removes CF-based deposits while preventing pattern damage and collapse, ensuring precision in fine pattern formation.
Implementation Method 1
a step of forming an oxide including an oxide of the CF-based deposit using oxygen-containing radicals
Implementation Method 2
a step of removing the oxide including the oxide of the CF-based deposit by radical processing or chemical processing using gas
Data Source
AI summary
An etching method includes a step of preparing a substrate having a portion to be etched, a step of plasma-etching the portion to be etched of the substrate into a predetermined pattern using plasma of a processing gas containing a CF-based gas, and then a step of removing a CF-based deposit which remains as an etching residue. The step of removing the CF-based deposit includes a step of forming an oxide including an oxide of the CF-based deposit using oxygen-containing radicals, and a step of removing the generated oxide by radical processing or chemical processing using gas.