Electrochemical Apparatus for Semiconductor Native Oxide Removal
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Solution Overview
Problem
The existing methods for processing semiconductor substrates, particularly those containing silicon, germanium, or III-V elements, face inefficiencies in oxidation and native oxide removal, leading to poor stoichiometry of oxide films and complex switching between different reaction conditions during digital etching.
Innovation Solution
An electrochemical apparatus is employed, utilizing a high resistance virtual counter electrode and adjustable substrate holder to control particle removal and deposition on semiconductor wafers, allowing for efficient native oxide removal and hydrogen termination through controlled electrical bias, thereby achieving a hydrophobic surface suitable for further processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high temperature treatment is used to remove native oxide, then oxide removal is achieved, but metallic species formation occurs on the substrate
Solution Approach 1:
The patent replaces thermal processing (high temperature treatment) with electrochemical processing. Instead of using heat to remove native oxide, the invention uses electrochemical reactions in an electrolyte solution to achieve oxide removal and surface cleaning without causing metallic species formation, thus eliminating the harmful side effect while maintaining the beneficial oxide removal function
Solution Approach 2:
The patent changes the processing parameters from high temperature conditions to electrochemical conditions with controlled voltage and current. By applying specific voltage ranges (e.g., -0.5V to -2.0V vs. Ag/AgCl reference electrode) and using appropriate electrolyte compositions, the process achieves effective oxide removal without the adverse effects of thermal processing
2Manufacturing precision
If wet chemical oxidation is used, then oxide film is formed, but the oxide film has poor stoichiometry
Solution Approach 1:
The patent replaces wet chemical oxidation with electrochemical oxidation. Instead of using chemical reagents that produce poorly stoichiometric oxide films, the invention uses controlled electrochemical reactions to form oxide films with superior stoichiometry and composition control, achieving both oxide film formation and compositional stability
3Manufacturing precision
If digital etching process is used, then etching is achieved, but complex switching between different reaction conditions is required
Solution Approach 1:
The patent creates a universal electrochemical processing system that can perform multiple functions (oxide removal, surface cleaning, hydrogen termination, and etching) through a single integrated process. By adjusting voltage, current density, and electrolyte composition, the same electrochemical cell accomplishes what previously required multiple separate processes with complex switching between O3/H2O and HF/H2O conditions
Solution Approach 2:
The patent achieves different processing outcomes by changing electrochemical parameters (voltage, current density, electrolyte composition, temperature) rather than switching between entirely different chemical systems. This allows continuous adjustment between oxidation and etching modes within a single unified process framework
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 enables effective removal of native oxide, improving the hydrophobicity of the substrate surface and facilitating subsequent epitaxial deposition and nanowire formation without the need for complex switching between reaction conditions, enhancing the overall efficiency and quality of semiconductor device fabrication.
Implementation Method 1
An electrochemical apparatus is employed, utilizing a high resistance virtual counter electrode and adjustable substrate holder to control particle removal and deposition on semiconductor wafers
Implementation Method 2
enables effective removal of native oxide, improving the hydrophobicity of the substrate surface
Implementation Method 3
allowing for efficient native oxide removal and hydrogen termination through controlled electrical bias
Data Source
AI summary
A method includes depositing a plurality of first semiconductor layers and a plurality of second semiconductor layers over a substrate, wherein the first semiconductor layers and the second semiconductor layers are stacked alternately; patterning the first and second semiconductor layers to form a fin structure; supplying a first bias to the substrate after patterning the first and second semiconductor layers; and etching the second semiconductor layers when the semiconductor substrate is supplied with the first bias, wherein etching the second semiconductor layers is performed such that the first semiconductor layers are suspended above the substrate.