Wafer Defect Location Accuracy via Swath Correction
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Solution Overview
Problem
Current methods for determining defect locations on wafers are limited by inspection tool accuracy and lack consideration for swath-related errors, resulting in defect location accuracy (DLA) that is only improved by manual alignment, which is insufficient for advanced semiconductor manufacturing.
Innovation Solution
A computer-implemented method that aligns design coordinates with images from a defect review tool for defects detected in multiple swaths, determining position offsets for each swath and applying correction factors to improve defect location accuracy, using a computer system to integrate inspection and design technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual alignment method is used to improve defect location accuracy, then alignment between wafer coordinate system and design coordinate system is improved, but swath-related location errors are not addressed and DLA is limited to several times the inspection pixel size
Solution Approach 1:
The patent divides the wafer into multiple swaths and performs separate alignment and error correction for each swath. Instead of applying a single global alignment transformation, the system segments the correction process into individual swath-specific transformations, allowing each swath's unique location errors to be addressed independently. This segmentation enables the system to overcome the limitation of manual alignment that only corrects two sites for the whole wafer.
Solution Approach 2:
The patent applies local quality by determining defect position offsets specifically for each swath based on its unique characteristics. Each swath receives a customized correction factor rather than a uniform correction applied globally. This local approach ensures that swath-related location errors are addressed with precision tailored to each specific region of the wafer, improving overall defect location accuracy beyond what global manual alignment can achieve.
2Measurement precision
If inspection tool capability is improved to enhance defect detection accuracy, then defect detection capability is improved, but DLA is still limited by stage accuracy and run-time alignment
Solution Approach 1:
The patent introduces defect position offsets as an intermediary correction layer between the inspection tool's raw measurements and the final defect location coordinates. These offsets act as a mediator that compensates for stage accuracy and run-time alignment errors. By applying this intermediary correction based on swath-specific alignment data, the system can achieve high manufacturing precision even when the inspection tool's inherent accuracy is limited.
3Measurement precision
If two or more defects from each swath are aligned to design images, then defect position offsets for each swath can be determined, but processing complexity increases
Solution Approach 1:
The patent applies partial action by selecting only two or more representative defects from each swath for alignment purposes, rather than processing all detected defects. This selective approach provides sufficient data to determine accurate defect position offsets for each swath while avoiding the excessive processing complexity that would result from analyzing every defect. The method achieves the necessary precision with a minimal sufficient subset of defects.
Data Source
AI summary
Methods and systems for determining design coordinates for defects detected on a wafer are provided. One method includes aligning a design for a wafer to defect review tool images for defects detected in multiple swaths on the wafer by an inspection tool, determining a position of each of the defects in design coordinates based on results of the aligning, separately determining a defect position offset for each of the multiple swaths based on the swath in which each of the defects was detected (swath correction factor), the design coordinates for each of the defects, and a position for each of the defects determined by the inspection tool, and determining design coordinates for the other defects detected in the multiple swaths by the inspection tool by applying the appropriate swath correction factor to those defects.