Semiconductor Wafer Defect Screening Across Heat Treatment Stages
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Solution Overview
Problem
Existing semiconductor defect inspection methods face challenges in accurately classifying defect types due to expansion or contraction during heat treatment processes, and the superimposition of chip patterns complicates defect classification accuracy.
Innovation Solution
A semiconductor inspection apparatus that utilizes a first inspection unit for surface unevenness information before ion implantation and a second unit for photoluminescence after heat treatment, combined with a screening unit to specify defects and determine quality, employing image analysis and machine learning models to improve classification accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If defect inspection is performed before the entire heat treatment process is completed, then the inspection process is faster and does not include chip pattern contrast, but the inspection result does not reflect the influence of expansion or contraction of the defect
Solution Approach 1:
The patent performs a preliminary inspection before the entire heat treatment process to capture initial defect characteristics, then performs a second inspection after heat treatment to capture defect expansion/contraction. By combining both inspections with machine learning, the system achieves accurate defect classification that reflects both the initial state and the thermal process influence.
2Measurement precision
If the defect inspection is performed after the thermal process is completed, then the defect expansion or contraction is reflected in the inspection result, but the contrast caused by the chip pattern formed on the semiconductor wafer is superimposed on the inspection result
Solution Approach 1:
The patent extracts and removes the chip pattern contrast from the inspection results through image processing techniques. By separating the pattern information from the defect information, the system preserves the defect expansion/contraction characteristics while eliminating the interfering pattern superposition.
3Productivity
If a single inspection method is used, then the inspection process is simpler and faster, but the classification accuracy of the defect type decreases
Solution Approach 1:
The patent merges multiple inspection results (before and after heat treatment) with different imaging techniques into a unified defect classification system. By combining the preliminary inspection data with the post-heat-treatment inspection data and processing them through machine learning algorithms, the system achieves high classification accuracy while maintaining process 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
Enhances defect classification accuracy and quality determination of semiconductor chips, reducing the introduction of defective products by accurately identifying defects that may degrade over time, even after heat treatment, and improving yield.
Implementation Method 1
a first inspection information acquisition unit that acquires first image information. The first image information includes unevenness information on a surface of a semiconductor wafer before ion implantation
Implementation Method 2
a second inspection information acquisition unit that acquires second image information. The second image information includes information on photoluminescence in the semiconductor wafer subjected to heat treatment after the ion implantation
Data Source
AI summary
A semiconductor inspection apparatus includes first inspection information acquisition circuitry, second inspection information acquisition circuitry, and screening circuitry. The first inspection information acquisition circuitry acquires first image information including unevenness information on the surface of a semiconductor wafer before ion implantation. The second inspection information acquisition circuitry acquires second image information including information on photoluminescence in the semiconductor wafer subjected to heat treatment after the ion implantation. The screening circuitry specifies a defect included in the semiconductor wafer on the basis of the first image information and the second image information, and determines the quality of a semiconductor chip formed on the semiconductor wafer.