Boron Sidewall Passivation for Uniform Plasma-Etched Features
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Solution Overview
Problem
As device sizes in semiconductor systems continue to shrink, maintaining the dimensions and integrity of features during etching operations becomes challenging, particularly due to the formation of uneven or tapered sidewalls.
Innovation Solution
The method involves depositing a boron-containing material on the substrate, extending along the sidewalls of features, and then etching these features using plasma effluents of an oxygen-containing precursor, while maintaining a temperature below 50°C and pressure between 5 mTorr and 100 mTorr.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional etching methods are used to create smaller features, then device size reduction is achieved, but sidewall uniformity and feature dimension control deteriorate due to tapered or uneven sidewalls
Solution Approach 1:
A boron-containing passivation material is deposited on the substrate before the etching process begins. This preliminary deposition creates a protective layer on the sidewalls that prevents etchant attack during the etching process, thereby maintaining vertical sidewalls and uniform feature dimensions even as feature sizes are reduced
Solution Approach 2:
The boron-containing material serves as an intermediary protective layer between the etchant plasma and the feature sidewalls. This intermediate layer selectively protects the sidewalls from etching while allowing the etch process to proceed on the substrate, enabling precise control of feature dimensions and sidewall uniformity
2Manufacturing precision
If iterative etching and deposition cycles are performed to maintain feature dimensions, then manufacturing precision is improved, but processing time increases
Solution Approach 1:
The passivation material is deposited once before the etching sequence begins, rather than requiring multiple iterative deposition-etching cycles. This single preliminary deposition maintains feature dimensions throughout the entire etching process, significantly reducing total processing time while preserving manufacturing precision
Solution Approach 2:
The passivation layer remains in place throughout the continuous etching process, providing ongoing protection to the sidewalls. This continuous protection eliminates the need to stop and redeposit material between etching steps, enabling uninterrupted etching while maintaining feature dimension 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
This approach effectively passivates sidewalls, maintains feature dimensions, and allows for deeper and more uniform feature formation, improving throughput and reducing structural flaws in semiconductor devices.
Implementation Method 1
etching one or more features in a substrate disposed within a processing region of a semiconductor processing chamber with plasma effluents of an oxygen-containing precursor
Implementation Method 2
depositing a boron-containing material on the substrate. The boron-containing material may extend along sidewalls of the one or more features in the substrate
Implementation Method 3
The contacting may oxidize the boron-containing material
Implementation Method 4
A temperature may be maintained at less than or about 50° C. while contacting the substrate with plasma effluents of the oxygen-containing precursor and while depositing the boron-containing material on the substrate
Data Source
AI summary
Exemplary semiconductor processing methods may include depositing a boron-containing material on the substrate. The boron-containing material may extend along sidewalls of the one or more features in the substrate. The methods may include forming a plasma of an oxygen-containing precursor and contacting the substrate with plasma effluents of the oxygen-containing precursor. The contacting may etch a portion of the one or more features in the substrate. The contacting may oxidize the boron-containing material.