Pattern Inspection Apparatus for Multiple Patterning Position Deviation
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Solution Overview
Problem
Current pattern inspection apparatuses face challenges in accurately measuring position deviations across entire masks, especially when multiple patterning techniques are used, leading to potential defects in wafer patterns due to positional inaccuracies and limited field of view, which increases inspection time and costs.
Innovation Solution
A pattern inspection apparatus and method that includes an optical image acquiring mechanism, position deviation map generating processing circuitry, difference position value map generating processing circuitry, region specifying processing circuitry, and output mechanism to analyze and specify regions with significant position deviations between masks, enabling precise defect detection and correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pattern inspection apparatus measures position deviations of all patterns on an entire mask using a limited field of view, then measurement accuracy is improved, but total measurement time increases significantly
Solution Approach 1:
The mask surface is divided into multiple regions of interest (ROIs), each containing specific patterns that require position deviation measurement. The inspection apparatus measures only these specific regions rather than the entire mask, segmenting the measurement task to reduce total measurement time while maintaining accuracy for critical patterns.
Solution Approach 2:
Different regions of the mask are treated differently based on their importance. Critical patterns that require high measurement accuracy are identified and measured with high precision, while non-critical regions are either measured with lower precision or excluded from measurement, applying local quality differentiation to optimize the balance between accuracy and time.
2Quantity of substance
If multiple masks are used for multiple patterning, then pattern density and integration are improved, but position deviation accumulation between masks causes defects
Solution Approach 1:
Position deviation maps from multiple masks are merged and overlaid to identify regions where deviations accumulate and cause defects. By combining the position deviation information from multiple masks, the system can detect cumulative errors that would not be apparent when examining each mask individually, enabling corrective action before defects occur.
Solution Approach 2:
The system provides feedback by identifying specific regions where position deviations from multiple masks accumulate to create defects. This feedback information is used to adjust alignment and positioning for subsequent masks, preventing defect formation and maintaining manufacturing precision across multiple patterning steps.
3Measurement precision
If inspection sensitivity is increased to detect smaller defect dimensions, then detection capability is improved, but inspection complexity and cost increase
Solution Approach 1:
High inspection sensitivity is applied locally only to critical regions and pattern types where small defects have the greatest impact. Non-critical regions use standard inspection sensitivity, reducing the overall complexity and cost of the inspection system while maintaining high detection capability where it is most needed.
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 solution allows for high-accuracy detection and correction of position deviations across multiple masks, reducing the risk of defects in wafer patterns and improving inspection efficiency by generating detailed position deviation maps and specifying critical regions for repair.
Implementation Method 1
A light beam is emitted to the mask by a light source and an illumination optical system. Light that is transmitted through the mask or reflected from the mask forms an image on a sensor through the optical system.
Data Source
AI summary
A pattern inspection apparatus includes: an optical image acquiring mechanism to acquire optical image data of a corresponding divided pattern for each of masks for multiple patterning has been formed; a position deviation map generating processing circuitry to generate position deviation maps regarding the corresponding divided pattern; a difference position value map generating processing circuitry to generate one difference position value map defining a difference value between relative position deviation amounts of the each minimum element of the position deviation maps; a region specifying processing circuitry to specify at least one region having the difference value exceeding a threshold of distance between patterns laying side-by-side by using the difference position value map; and an output mechanism to output at least coordinates, a type of defect, and information of a reference image of each region specified for the each region specified.