Dielectric Etching Selectivity via HF-CxHyFz Plasma
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Solution Overview
Problem
Existing substrate processing techniques face challenges in achieving high selectivity of dielectric films to masks during etching, with existing methods not effectively optimizing the etching process to improve selectivity and prevent mask film damage.
Innovation Solution
A substrate processing method involving a reaction gas mixture of HF and CxHyFz gases, where the HF gas flow rate exceeds that of CxHyFz gases, and the substrate is maintained at 0°C or lower, with alternating electrical biases and RF power to generate plasma, enhancing the etching selectivity and reducing mask film damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used, then the etching process can proceed, but the selectivity of dielectric film to mask is insufficient and mask film damage occurs
Solution Approach 1:
The patent applies parameter changes by optimizing the reaction gas composition (using CF4, C4F8, and H2 in specific ratios), substrate temperature (maintaining at 0°C or lower), and pressure conditions to achieve high etching selectivity while protecting the mask film from damage
Solution Approach 2:
The patent uses a composite gas mixture of CF4, C4F8, and H2 rather than a single gas, leveraging the synergistic effects of different gases to achieve both high etching rates and mask protection through formed protective films
2Productivity
If higher etching rates are achieved, then productivity increases, but selectivity deteriorates and mask damage increases
Solution Approach 1:
The patent maintains high productivity through optimized pressure conditions and gas flow rates while preserving selectivity by controlling substrate temperature at 0°C or lower and using specific gas composition ratios, achieving both high etching rates and high selectivity simultaneously
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 method significantly improves the selectivity of dielectric films to mask films during etching, maintaining feature integrity and reducing mask film etching rates, while maintaining appropriate etching rates for dielectric films.
Implementation Method 1
etching the dielectric film with plasm generated from a reaction gas containing an HF gas and at least one CxHyFz gas
Data Source
AI summary
A substrate processing method includes placing a substrate with a dielectric film on a substrate support in a chamber, and etching the dielectric film with plasm generated from a reaction gas containing an HF gas and at least one CxHyFz gas selected from the group consisting of a C4H2F6 gas, a C4H2F8 gas, a C3H2F4 gas, and a C3H2F6 gas. The etching includes setting the substrate support at a temperature of 0° C. or lower and setting the HF gas to a flow rate greater than a flow rate of the CxHyFz gas.