Silicon Carbide Substrate Alignment for Defect-Based Die Screening
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Solution Overview
Problem
Current methods for manufacturing silicon carbide semiconductor devices lack accuracy in determining the pass/fail status of device active regions due to inadequate defect positioning and coordination systems.
Innovation Solution
A method involving the formation of reference marks on silicon carbide substrates and epitaxial films to specify two-dimensional position coordinates, followed by polishing and cleaning to enhance defect detection and device active region formation, allowing for precise pass/fail judgments and improved yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference marks are formed on the silicon carbide substrate before polishing and cleaning, then the position coordinates of defects and device active regions can be accurately specified, but the reference marks may be damaged or distorted during subsequent processing steps
Solution Approach 1:
The reference marks are formed in advance on the silicon carbide substrate before the polishing and cleaning steps. This preliminary action allows the coordinate system to be established early, enabling accurate position specification for subsequent defect detection and device active region formation, while the marks are protected through careful process sequencing
Solution Approach 2:
The method accounts for potential damage or distortion to reference marks during polishing and cleaning by establishing a margin of error in the coordinate system or performing additional verification steps after processing to ensure the reference marks remain functional for position specification
2Manufacturing precision
If polishing and cleaning are performed after reference mark formation, then the surface quality is improved for better defect detection, but the reference marks may be altered or removed
Solution Approach 1:
Reference marks are formed before polishing and cleaning operations, establishing the coordinate system in advance. The marks are designed to withstand subsequent processing, and their positions are recorded and protected through digital documentation to prevent information loss even if physical marks are altered
Solution Approach 2:
The reference mark positions and coordinate information are captured and stored as digital data before polishing and cleaning. This creates a backup copy of the reference information that can be used for defect position specification even if the physical reference marks are modified or removed during surface treatment
Data Source
AI summary
A method of manufacturing a silicon carbide semiconductor device includes the following steps. In a silicon carbide substrate including a silicon carbide single-crystal substrate and a silicon carbide epitaxial film provided on the silicon carbide single-crystal substrate, a reference mark serving as a reference of two dimensional position coordinates is formed. After forming the reference mark, at least one of polishing or cleaning is performed on a reference mark formation surface of the silicon carbide substrate. Position coordinates of a defect present in the silicon carbide substrate are specified based on the reference mark. A device active region is formed in the silicon carbide substrate. Position coordinates of the device active region are specified based on the reference mark. A pass/fail judgement of the device active region is made by associating the position coordinates of the defect with the position of the device active region.