Silicon Film Plasma Etching With Phosphorus Sidewall Protection
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Solution Overview
Problem
Current plasma etching methods for silicon-containing films face challenges in achieving high etching rates and selectivity while minimizing side etching and bowing, particularly when using conventional process gases like fluorocarbons and hydrofluorocarbons.
Innovation Solution
The method involves using a process gas containing a phosphorus gas component, a fluorine gas component, and a hydrogen gas component, with a halogen gas component, and applying pulsed bias electric power to enhance etching efficiency and selectivity, forming a protective film with phosphorus-oxygen bonds to reduce side wall etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional process gases (fluorocarbons, hydrofluorocarbons) are used for plasma etching of silicon-containing films, then the etching process can be performed, but the etching rate and selectivity are insufficient while side etching and bowing occur
Solution Approach 1:
The patent changes the chemical composition parameters of the process gas by introducing phosphorus-containing gases (PF3, PCl3, PBr3, PH3) in combination with fluorine-containing gases and hydrogen-containing gases. This parameter change transforms the etching chemistry to achieve higher etching rates while improving selectivity and reducing side etching and bowing effects that occur with conventional fluorocarbon and hydrofluorocarbon gases
Solution Approach 2:
The patent uses composite process gas mixtures containing multiple components: phosphorus-containing gases, fluorine-containing gases, and hydrogen-containing gases. This composite approach combines the benefits of different gas types to achieve high etching rates with improved precision, eliminating the trade-off between productivity and manufacturing precision
2Productivity
If high etching rate is achieved with conventional gases, then productivity improves, but selectivity deteriorates and side etching increases
Solution Approach 1:
The patent modifies the process gas composition by adding phosphorus-containing components (PF3, PCl3, PBr3, or PH3) to the fluorocarbon or hydrofluorocarbon base gas. This chemical parameter change enables the plasma to achieve high etching rates while maintaining high selectivity between different film layers, resolving the contradiction between productivity and reliability
3Manufacturing precision
If conventional plasma etching is performed, then the silicon-containing film can be etched, but bowing of the etched structure occurs reducing precision
Solution Approach 1:
The patent changes the chemical environment by introducing phosphorus-containing gases that modify the plasma chemistry. This parameter change reduces bowing of the etched structures while maintaining high etching rates, simultaneously improving both manufacturing precision and productivity
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 significantly increases the etching rate and selectivity of silicon-containing films while minimizing side etching and bowing, as demonstrated by experimental results showing improved etching rates and reduced recess width.
Implementation Method 1
forming a protective film with phosphorus-oxygen bonds
Implementation Method 2
etching the silicon-containing film with a chemical species in plasma generated from a process gas
Implementation Method 3
etching the silicon-containing film with a chemical species in plasma
Data Source
AI summary
An etching method in accordance with the present disclosure includes providing a substrate, which includes a silicon-containing film, in a chamber; and etching the silicon-containing film with a chemical species in plasma generated from a process gas supplied in the chamber. The process gas includes a phosphorus gas component and a fluorine gas component.