Pattern Inspection Reference Image Filtering for Faster Accuracy
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Solution Overview
Problem
Existing pattern inspection methods face challenges in achieving high accuracy and efficiency due to the need for generating numerous filter functions, leading to prolonged processing times, especially when inspection conditions are similar to past inspections.
Innovation Solution
A pattern inspection apparatus and method that utilize a parameter range setting circuit to narrow the range of reference image generation parameters, such as resize amount and corner rounding amount, to generate filter function candidates, thereby reducing the number of combinations needed and accelerating the filter function determination process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of filter functions are generated using reference image generation parameters in a wide range, then inspection accuracy is improved, but processing time becomes excessively long
Solution Approach 1:
The system performs preliminary actions by storing inspection condition parameters and their corresponding optimal filter functions from past inspections in a database. When a new inspection is performed, the system first checks if similar inspection conditions exist in the database, and if so, directly retrieves the pre-determined filter function without regenerating it, thus avoiding time-consuming processing while maintaining accuracy.
Solution Approach 2:
The system changes parameters by comparing current inspection condition parameters with stored past inspection parameters, and based on the degree of similarity, dynamically selects or adjusts the filter function. This allows the system to adapt filter function selection to varying inspection conditions while avoiding full regeneration, balancing accuracy and processing time.
2Measurement precision
If the range of reference image generation parameters is widened to improve accuracy, then more filter function candidates are generated, but the complexity of the process increases
Solution Approach 1:
The system performs preliminary actions by pre-calculating and storing optimal filter functions for various inspection conditions in a database. This eliminates the need to repeatedly perform complex filter function generation processes, reducing processing complexity while maintaining the ability to access accurate filter functions when needed.
Solution Approach 2:
The system uses copying by retrieving and reusing filter functions from the database that were generated from similar past inspection conditions. Instead of regenerating filter functions from scratch, the system copies proven effective filter functions and applies them to current inspections, simplifying the process while maintaining accuracy.
Data Source
AI summary
According to one aspect of the present invention, a pattern inspection apparatus includes a parameter range setting circuit configured to set a range of a reference image generation parameter according to a coincidence degree with a past inspection condition parameter, a filter function generation circuit configured to generate a plurality of filter function candidates, using values in a set range of the reference image generation parameter, a determination circuit configured to determine a filter function for generating a reference image in the plurality of filter function candidates generated, a reference image generation circuit configured to generate a reference image by using the filter function determined, and a comparison circuit configured to compare the optical image with the reference image, wherein the reference image generation parameter is at least one of a resize amount and a corner rounding amount.