Anodic Oxide Film Electrolyte for Dense, Pore-Free Semiconductor Parts
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Solution Overview
Problem
Existing methods for forming anodic oxide films on semiconductor device components, such as showerheads, suffer from issues like corrosion, pore formation, and thickness-related defects, leading to decreased corrosion resistance and process inefficiencies.
Innovation Solution
An electrolyte composition comprising citric acid and additives like tartaric acid, sulfuric acid, and sodium acetate is used to form an anodic oxide film with a thickness of 500 nm to 900 nm, without forming a porous layer, by controlling current, temperature, and time during the anodizing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the anodic oxide film is increased to protect aluminum members, then corrosion resistance is improved, but hole size deviation occurs in spray nozzles and cracks form due to high-temperature process
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a mixed acid system (sulfuric acid, oxalic acid, and hydrofluoric acid) with specific concentration ratios. This parameter change enables the formation of a dense, non-porous oxide film that resists cracking and maintains dimensional stability during high-temperature processing, thereby preserving hole size uniformity while achieving adequate corrosion resistance
Solution Approach 2:
The patent creates a composite oxide film structure through the mixed acid electrolyte treatment. The synergistic interaction of multiple acids produces a complex oxide layer with enhanced mechanical properties, including improved flexibility and crack resistance, allowing the film to accommodate thermal expansion without compromising the underlying spray nozzle hole geometry
2Manufacturing precision
If the thickness of the anodic oxide film is reduced to avoid cracks and maintain hole uniformity, then manufacturing precision is improved, but corrosion resistance deteriorates due to porous layer formation
Solution Approach 1:
The patent modifies the electrolyte composition parameters by incorporating hydrofluoric acid in controlled amounts alongside sulfuric and oxalic acids. This parameter adjustment enables the formation of a thin yet dense oxide film that achieves adequate corrosion resistance without developing a porous structure, thereby maintaining both manufacturing precision and reliability
Solution Approach 2:
The patent creates a oxide film with locally optimized properties through the mixed acid system. The specific acid combination produces a film with non-uniform chemical composition at different depths, forming a dense, corrosion-resistant barrier layer at the surface while maintaining overall film thinness to prevent crack formation and preserve hole geometry
3Ease of manufacture
If existing anodic oxidation methods are used, then the process is simple and low-cost, but defects occur inside the coating layer when thickness reaches 200 nm or greater
Solution Approach 1:
The patent changes the electrolyte composition parameters by using a mixed acid system with specific concentration ratios. This parameter modification allows the formation of defect-free coating layers even at thicknesses of 200 nm and above, eliminating internal defects while preserving the simplicity and cost-effectiveness of the anodizing process
4Ease of manufacture
If aluminum members are used in vacuum plasma devices, then device complexity is reduced and ease of manufacture is improved, but corrosion occurs due to reaction with fluorine-based reactive gases
Solution Approach 1:
The patent creates a composite protective oxide film on aluminum members through mixed acid anodizing. This composite film structure, formed by the synergistic action of multiple acids, provides enhanced corrosion resistance against fluorine-based reactive gases while maintaining the ease of manufacture associated with aluminum components
Solution Approach 2:
The patent modifies the surface chemistry parameters of aluminum members by controlling the electrolyte composition and anodizing conditions. These parameter changes transform the reactive aluminum surface into a stable, corrosion-resistant oxide-covered surface that can withstand exposure to fluorine-based gases in vacuum plasma devices
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
The method provides an anodic oxide film with enhanced corrosion resistance and uniformity, preventing pore formation and maintaining process stability, thus reducing maintenance costs and improving semiconductor manufacturing efficiency.
Implementation Method 1
forming an anodic oxide film on a metal member by immersing the metal member in the electrolyte
Implementation Method 2
anodic oxidation treatment
Data Source
AI summary
Proposed are an electrolyte for forming an anodic oxide film, the electrolyte including citric acid and an additive, wherein the citric acid accounts for 3.0 wt % or more and 6.0 wt % or less based on 100 wt % of the electrolyte, the additive includes one or more selected from among tartaric acid, sulfuric acid, and sodium acetate, and the additive accounts for 0.5 wt % or more and 4.0 wt % or less based on 100 wt % of the electrolyte, a method of forming an anodic oxide film using the electrolyte, and an anodic oxide film and a member for a semiconductor device manufactured thereby.