Plasma Etchant Ratio Control for Selective Substrate Etching
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Solution Overview
Problem
Existing semiconductor fabrication processes face challenges in effectively controlling etching selectivity, particularly for materials like silicon-germanium, which requires higher selectivity than silicon, and process variations necessitate varied control of etching speed and critical dimension precision.
Innovation Solution
A substrate processing method and apparatus that dynamically controls etching selectivity by generating a process etchant from a preliminary etchant composed of first and second etchants through plasma ignition, adjusting their composition ratio, and using a fluorine-contained gas to create a controlled etching environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching processes are used, then etching speed can be maintained, but etching selectivity between different materials (e.g., SiGe vs Si) cannot be effectively controlled
Solution Approach 1:
The patent implements dynamic control of etching selectivity by adjusting the composition ratio of first and second etchants in real-time during the etching process. The plasma generation unit varies the ratio of first etchant (from first process gas) to second etchant (from second process gas) based on the specific material being etched, enabling adaptive optimization for different materials like SiGe or Si while maintaining high selectivity and etching speed.
2Productivity
If fixed composition etchant is used, then process stability is maintained, but dynamic adjustment of etching speed and selectivity is limited
Solution Approach 1:
The patent changes the compositional parameters of the etchant by independently controlling the flow rates of first process gas and second process gas. The plasma generation unit adjusts the concentration ratios of first etchant and second etchant dynamically, allowing precise control of etching speed and selectivity without requiring complex external control systems, as the adjustment is integrated into the plasma generation process itself.
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
Enables selective etching of various film types with controlled etching selectivity, enhancing precision and adaptability in semiconductor device fabrication.
Implementation Method 1
generating a preliminary etchant, which includes first and second etchants, from the process gas through plasma ignition
Implementation Method 2
processing the substrate with the process etchant
Data Source
AI summary
A substrate processing apparatus, a substrate processing method, and a method of fabricating a semiconductor device are provided. The substrate processing method includes providing a process gas, generating a preliminary etchant, which includes a first etchant and a second etchant, from the process gas through plasma ignition, generating a process etchant by controlling a composition ratio of the preliminary etchant, and performing a selective etching of the substrate with the process etchant.