Silicon Carbide Surface Cleanliness Evaluation by Mixed Acid ICP-MS
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Solution Overview
Problem
Existing methods fail to accurately evaluate metal contamination on silicon carbide-based members used in silicon wafer manufacturing, leading to potential device property degradation due to metal diffusion from these members during the manufacturing process.
Innovation Solution
A method involving contact of the silicon carbide surface with a mixed acid of hydrofluoric acid, hydrochloric acid, and nitric acid, followed by concentration and quantitative analysis using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) to assess metal contamination levels, allowing for high-accuracy evaluation of cleanliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional cleaning methods are used for silicon carbide-based members, then the cleaning process is simple, but the evaluation of metal contamination accuracy is insufficient
Solution Approach 1:
The patent introduces a mixed acid solution (comprising hydrofluoric acid, hydrochloric acid, and nitric acid) as an intermediary medium to transfer metal contaminants from the silicon carbide surface to the solution. This intermediary enables accurate measurement of metal contamination by converting the surface contamination problem into a solution-phase analysis problem that can be precisely quantified using ICP-MS technology.
Solution Approach 2:
The patent replaces conventional visual or simple chemical inspection methods with Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) technology. This substitution transforms the evaluation method from mechanical/visual inspection to a highly sensitive spectroscopic analysis, achieving detection limits at the parts per billion level for metal contaminants.
2Reliability
If no cleaning evaluation is performed, then the manufacturing process is efficient, but metal contamination affects device properties
Solution Approach 1:
The patent implements cleaning evaluation as a preliminary step before silicon wafer manufacturing. By assessing and ensuring the cleanliness of silicon carbide-based members (such as susceptors and heat shielding members) before they contact the wafers, the method prevents metal contamination from occurring during the manufacturing process, thereby ensuring device property consistency without requiring rework or rejection of contaminated products.
Solution Approach 2:
The patent establishes a feedback mechanism where the metal contamination levels measured by ICP-MS are used to evaluate and adjust cleaning process parameters. The quantitative data on metal contamination (such as iron, nickel, copper content) provides feedback to optimize cleaning conditions, ensuring that cleaning effectiveness is continuously improved while maintaining manufacturing efficiency.
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 enables precise evaluation of metal contamination on silicon carbide-based members, determining suitable cleaning conditions to reduce metal contamination in silicon wafers and ensure high cleanliness standards during manufacturing.
Implementation Method 1
bringing the silicon carbide surface into contact with a mixed acid of hydrofluoric acid, hydrochloric acid and nitric acid
Implementation Method 2
concentrating the mixed acid brought into contact with the silicon carbide surface by heating
Implementation Method 3
subjecting a sample solution obtained by diluting a concentrated liquid obtained by the concentration to quantitative analysis of metal components by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)
Data Source
AI summary
A method of evaluating cleanliness of a member having a silicon carbide surface, the method including bringing the silicon carbide surface into contact with a mixed acid of hydrofluoric acid, hydrochloric acid and nitric acid; concentrating the mixed acid brought into contact with the silicon carbide surface by heating; subjecting a sample solution obtained by diluting a concentrated liquid obtained by the concentration to quantitative analysis of metal components by Inductively Coupled Plasma-Mass Spectrometry; and evaluating cleanliness of the member having a silicon carbide surface on the basis of a quantitative result of metal components obtained by the quantitative analysis.