Intra-die Defect Detection Using Aperiodic POI Comparison
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Solution Overview
Problem
Current semiconductor defect detection methods, particularly those focusing on patterns of interest (POIs), struggle with intra-die inspections due to common mode defects canceling out and the inability to analyze differences between adjacent dies, leading to inefficiencies and increased costs in defect correction.
Innovation Solution
A system and method for intra-die defect detection using an imaging subsystem and computer subsystems that generate and compare images of POIs at aperiodic locations within a die to a POI reference image, allowing for defect detection within individual dies without relying on die-to-die comparisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If die-to-die difference strategy is used for defect detection, then defects can be detected between adjacent dies, but common mode defects cancel out and intra-die defects cannot be detected
Solution Approach 1:
The patent segments the inspection approach by dividing POIs into two distinct groups: first POIs inspected using die-to-die difference strategy, and second POIs inspected using intra-die comparison strategy. This segmentation allows each strategy to be applied where it is most effective, resolving the contradiction between detecting inter-die defects and intra-die defects
Solution Approach 2:
The patent inverts the traditional die-to-die comparison approach by implementing an intra-die comparison approach for the second POIs. Instead of comparing across different dies, the system compares multiple instances within the same die, which enables detection of intra-die defects that would otherwise be missed by the conventional die-to-die method
2Measurement precision
If inspection sensitivity is increased to detect smaller defects, then more yield relevant defects are detected, but the population of nuisance defects also increases dramatically
Solution Approach 1:
The patent applies local quality by using different inspection strategies with different sensitivity characteristics for different POIs. The first POIs are inspected with one strategy while the second POIs are inspected with another strategy, allowing the system to optimize for yield relevant defects in certain areas while filtering nuisance defects in other areas
Solution Approach 2:
The patent changes the inspection parameters by switching between two different inspection strategies. The first strategy uses die-to-die difference comparison, while the second strategy uses intra-die comparison with a reference image generated from the same die. This parameter change allows the system to adapt to different defect types and reduce nuisance defect detection
3Adaptability or versatility
If multiple inspection strategies are used for different POIs, then both inter-die and intra-die defects can be detected, but the inspection process becomes more complex
Solution Approach 1:
The patent segments the POIs into two groups and applies different inspection strategies to each group. This segmentation simplifies the overall process by allowing each strategy to be optimized independently for its specific purpose, rather than trying to use a single complex strategy for all POIs
Solution Approach 2:
The patent applies partial action by using the intra-die comparison strategy specifically for the second POIs where it is most beneficial, while using the die-to-die strategy for the first POIs. This partial application of different strategies reduces overall complexity compared to applying a single comprehensive strategy to all POIs
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 enables effective intra-die defect detection, increasing inspection sensitivity and reducing noise, thereby improving defect detection capabilities and reducing the challenges associated with common mode defects.
Implementation Method 1
an energy source configured to generate energy that is directed to a specimen
Implementation Method 2
a detector configured to detect energy from the specimen and to generate images responsive to the detected energy
Data Source
AI summary
Methods and systems for detecting defects on a specimen are provided. One system includes one or more computer subsystems configured for acquiring images generated by an imaging subsystem at multiple instances of a pattern of interest (POI) within a die formed on the specimen. The multiple instances include two or more instances that are located at aperiodic locations within the die. The computer subsystem(s) are also configured for generating a POI reference image from two or more of the images generated at the multiple instances of the POI within the die. The computer subsystem(s) are further configured for comparing the images generated at the multiple instances of the POI within the die to the POI reference image and detecting defects in the multiple instances of the POI based on results of the comparing.