SiC Wafer Scribe Line Mark Placement for Defect Inspection
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Solution Overview
Problem
Conventional silicon carbide semiconductor device manufacturing methods incorrectly identify conforming products as non-conforming due to misrecognition of alignment marks as crystal defects, leading to reduced conforming product rates and increased chip costs.
Innovation Solution
The method involves forming scribe lines with marks on a silicon carbide semiconductor wafer, where the distance between the edge of the scribe line recognized by the inspection equipment and the mark is set between 10 μm to 25 μm, and the mark is placed only on specific scribe lines or in dedicated regions to avoid misrecognition, allowing for wider scribe lines to be recognized by the inspection equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alignment marks are placed on scribe lines for inspection purposes, then inspection accuracy is improved, but misrecognition of marks as crystal defects increases
Solution Approach 1:
A dedicated mark recognition region is introduced as an intermediary zone between the scribe line and the crystal defect inspection region. This region serves as a mediator that allows the inspection equipment to reliably identify alignment marks without mistaking them for crystal defects, thereby resolving the contradiction between inspection accuracy and conforming product rate
Solution Approach 2:
The scribe line region is segmented into a dedicated mark recognition region and a crystal defect inspection region. By dividing the inspection area and assigning specific functions to each region, the system can accurately identify marks in one region while inspecting for defects in another, eliminating misrecognition issues
2Measurement precision
If scribe line width is increased to improve mark recognition, then alignment accuracy is improved, but the area available for crystal defect inspection is reduced
Solution Approach 1:
The scribe line structure is segmented into multiple functional regions: a wider dedicated mark recognition region for improved alignment accuracy, and adjacent crystal defect inspection regions that maintain sufficient area for defect detection. This segmentation allows each region to be optimized for its specific purpose without compromising the other
3Reliability
If all chips with detected crystal defects are rejected, then product reliability is improved, but conforming product rate decreases due to misrecognition
Solution Approach 1:
The dedicated mark recognition region acts as an intermediary that enables the inspection equipment to distinguish between alignment marks and actual crystal defects. This prevents false rejection of conforming chips while maintaining the rejection of truly defective chips, thereby improving conforming product rate without compromising product reliability
Solution Approach 2:
The inspection system uses the dedicated mark recognition region to obtain feedback information about the presence and position of alignment marks. This feedback mechanism allows the system to adjust its defect detection algorithm to avoid misinterpreting marks as defects, thus maintaining high reliability while improving productivity
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 approach reduces misrecognition of marks as crystal defects, enabling the use of previously discarded chips as conforming products, thereby increasing the conforming product rate and decreasing chip costs.
Implementation Method 1
inspecting the epitaxial layer for a crystal defect using crystal defect inspection equipment, the crystal defect inspection equipment recognizing the plurality of scribe lines to be a plurality of recognized scribe lines
Data Source
AI summary
A method of manufacturing a silicon carbide semiconductor device. The method includes epitaxially growing an epitaxial layer on a starting substrate to form a semiconductor wafer, forming a plurality of scribe lines, including a first scribe line, in the epitaxial layer, forming a mark in the first scribe line, inspecting the epitaxial layer for a crystal defect using crystal defect inspection equipment, which recognizes the first scribe line as being a second scribe line, forming a device element structure in the semiconductor wafer, dicing the semiconductor wafer into semiconductor chips along the scribe lines, and identifying, as a conforming product candidate, one of the semiconductor chips that is free of the crystal defect detected during the inspecting. A distance between an edge of the second scribe line and an edge of the mark, when the first and second scribe lines are aligned, is in a range from 10 μm to 25 μm.