Semiconductor Substrate Quality Evaluation via Dry-Etching and Bright Point Detection
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Solution Overview
Problem
Existing methods for evaluating semiconductor substrate quality, particularly for metal contamination, are time-consuming and lack practicality as they fail to detect crystal defects and surface roughness caused by metal contamination, which can lead to defective products being shipped as non-defective.
Innovation Solution
A method involving dry-etching of the semiconductor substrate surface followed by detection of bright points using a foreign matter inspection device, with elemental analysis via scanning electron microscopy or transmission electron microscopy and energy-dispersion X-ray spectroscopy to identify metal contaminants, allowing for accurate evaluation of substrate quality and contamination levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If foreign matter inspection device is used to detect bright points on substrate surface, then surface particles and crystal defects can be detected, but metal contamination in bulk near surface cannot be detected
Solution Approach 1:
The patent applies preliminary action by performing dry-etching treatment on the semiconductor substrate surface before quality inspection. This etching process pre-exposes metal contaminants that are embedded in the bulk near the surface, making them detectable by the foreign matter inspection device in subsequent steps. The preliminary etching action transforms hidden contaminants into observable bright points, resolving the detection limitation.
2Measurement precision
If complex reference wafer comparison method is used to identify metal contaminants, then contamination can be detected, but evaluation becomes time-consuming and lacks practicality
Solution Approach 1:
The patent extracts the essential detection feature by focusing solely on the presence and distribution pattern of bright points on the etched substrate surface, eliminating the need for complex reference wafer comparisons. The method takes out only the necessary information (bright point characteristics) required for contamination evaluation, significantly simplifying the inspection process while maintaining detection accuracy.
Solution Approach 2:
The patent changes the detection parameters by evaluating quality based on the number and distribution pattern of bright points rather than comparing complex shapes against reference wafers. This parameter transformation converts a complex shape-matching problem into a simpler quantitative assessment, improving evaluation efficiency while maintaining reliability.
3Manufacturing precision
If mirror polishing process is used to finish substrate surface, then surface quality is improved, but metal ions from slurry diffuse into wafer causing bulk contamination
Solution Approach 1:
The patent converts the harmful effect of metal ion diffusion during mirror polishing into a beneficial detection opportunity. By using the same bright point detection method to identify metal contaminants that were introduced during polishing, the process transforms an unwanted side effect into a detectable signal that enables quality control and process improvement.
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 rapid and accurate identification of metal contaminants, ensuring high-quality semiconductor substrates are produced by distinguishing between defective and non-defective products, thereby improving manufacturing processes and product reliability.
Implementation Method 1
etching a surface of the semiconductor substrate using dry-etching
Implementation Method 2
detecting bright points on the surface of the etched surface with a foreign matter inspection device
Implementation Method 3
elemental analysis of the detected bright points. The elemental analysis may be conducted by a scanning electron microscope or transmission electron microscope, and an energy-dispersion X-ray spectroscopy
Data Source
AI summary
Methods for evaluating a quality of a semiconductor substrate. In one aspect, etching a surface of the semiconductor substrate by dry-etching, detecting bright points on the surface of the etched surface with a foreign matter inspection device, and evaluating the quality of the semiconductor substrate based on the number and/or distribution pattern of the detected bright points are included. In another aspect, etching a surface of the semiconductor substrate by dry-etching, detecting bright points on the surface of the etched surface with a foreign matter inspection device, and evaluating the quality of the semiconductor substrate are included, and the evaluated quality is a type of metal contaminant contained in the substrate, and the type of metal contaminant is identified by conducting elemental analysis of the detected bright points.