HF Plasma Etching with Pulsed Bias for Vertical Profiles
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Solution Overview
Problem
Existing etching methods struggle to achieve high verticality in etching processes, particularly when using process gases containing hydrocarbon and hydrofluorocarbon gases in plasma etching.
Innovation Solution
An etching method utilizing an etching apparatus with a chamber and substrate support, where a process gas containing HF is supplied and plasma is generated with radio-frequency power, accompanied by a pulsed voltage applied to the substrate support at a lower frequency, enhancing the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etching is performed using process gas containing hydrocarbon and hydrofluorocarbon gases, then etching capability is improved, but verticality of etching is insufficient
Solution Approach 1:
The patent applies periodic pulsed voltage to the substrate at a frequency lower than the plasma generation frequency. This periodic action creates distinct etching and non-etching phases, allowing polymer deposition during non-etching phases to protect sidewalls while enabling vertical etching during etching phases, thereby resolving the contradiction between etching capability and verticality
Solution Approach 2:
The patent changes the voltage application frequency parameter to be lower than the plasma frequency, creating a multi-frequency regime. This parameter change enables different physical processes to occur at different timescales, allowing simultaneous achievement of high etching rate and vertical profile control
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
The method significantly increases the verticality of etching, improving the precision and accuracy of etching processes.
Implementation Method 1
generating plasma from the process gas in the chamber with radio-frequency power having a first frequency
Implementation Method 2
applying a pulsed voltage periodically to the substrate support at a second frequency lower than the first frequency
Data Source
AI summary
A technique increases verticality in etching. An etching method is a method for etching a target film with a plasma processing apparatus including a chamber and a substrate support located in the chamber to support a substrate, the substrate support holding a substrate that includes the target film, the target film including a patterned mask film having at least one opening. The etching method includes supplying a process gas containing an HF gas into the chamber, and etching the target film by: generating plasma from the process gas in the chamber with radio-frequency power having a first frequency, and applying a pulsed voltage periodically to the substrate support at a second frequency lower than the first frequency.