Wafer Inspection Merging Multiple Process Steps
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Solution Overview
Problem
Current semiconductor manufacturing processes require multiple inspection steps, leading to increased time, effort, and the risk of particle contamination, as they only cover one-to-one correlations between process and inspection steps, necessitating additional wafer transfers and prolonged queue times.
Innovation Solution
A system and method utilizing an optical subsystem with a light source and detector, combined with computer subsystems, to inspect wafers after multiple process steps, allowing for the detection of defects and association with specific process steps based on the spatial relationship of defects to different portions of the design formed on the wafer, eliminating the need for intermediate inspections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple inspection steps are performed for multiple process steps, then defect detection coverage is improved, but inspection time and queue time increase
Solution Approach 1:
The patent combines multiple inspection steps into a single inspection step that performs all necessary inspections simultaneously. The inspection system executes one comprehensive inspection that covers all process steps, eliminating the need for separate inspection steps for each process step while maintaining complete defect detection coverage.
Solution Approach 2:
The single inspection step is designed to perform multiple inspection functions simultaneously. It can inspect for defects from different process steps, analyze multiple parameters, and provide comprehensive defect detection all in one operation, making the inspection system universal and multi-functional.
2Measurement precision
If multiple inspection steps are performed for multiple process steps, then defect detection accuracy is improved, but the number of wafer transfers increases
Solution Approach 1:
The patent merges multiple separate inspection operations into a single integrated inspection step. This eliminates the need to transfer wafers between multiple inspection tools or to perform sequential inspections at different stages, reducing wafer transfer operations while maintaining comprehensive defect detection accuracy through the unified inspection approach.
3Measurement precision
If multiple inspection steps are performed for multiple process steps, then process monitoring is improved, but risk of particle contamination increases
Solution Approach 1:
The patent consolidates multiple inspection steps into a single inspection operation, thereby reducing the number of times wafers are transferred between tools. Since each transfer operation introduces potential particle contamination risk, reducing transfers directly lowers contamination risk while the single comprehensive inspection step maintains effective process monitoring.
4Measurement precision
If multiple inspection steps are performed for multiple process steps, then inspection thoroughness is improved, but inspection effort and cost increase
Solution Approach 1:
The patent merges multiple inspection steps into one comprehensive inspection operation that achieves the same thoroughness as multiple separate inspections. By performing all necessary inspections in a single step rather than sequentially, the total inspection effort and associated costs are reduced while maintaining complete inspection coverage and thoroughness.
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 the number of inspection steps, minimizes wafer transfers, and enhances defect identification accuracy by correlating defects with the appropriate process steps, thereby reducing queue times and preventing contamination, while providing detailed defectivity reports for multiple process steps.
Implementation Method 1
The optical subsystem is configured to direct light generated by the light source to the wafer and to detect light from the wafer with the detector
Data Source
AI summary
Various embodiments for detecting defects on a wafer are provided. One method includes acquiring output generated by an inspection system for a wafer during an inspection process that is performed after at least first and second process steps have been performed on the wafer. The first and second process steps include forming first and second portions, respectively, of a design on the wafer. The first and second portions of the design are mutually exclusive in space on the wafer. The method also includes detecting defects on the wafer based on the output and determining positions of the defects with respect to the first and second portions of the design. In addition, the method includes associating different portions of the defects with the first or second process step based on the positions of the defects with respect to the first and second portions of the design.