Measuring Microscope Ambient Effect Compensation
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Solution Overview
Problem
Current measuring microscopes used in photolithography face challenges in accurately compensating for changes in ambient conditions such as temperature, air pressure, and humidity, which affect the optical path and magnification, leading to inaccuracies in measurements of nanometer-scale structures.
Innovation Solution
A method is developed to capture and compensate for the influence of ambient conditions by using a reference measurement system to measure changes in optical properties and correlating them with changes in the imaging scale, allowing for the adaptation of pixel sizes and image positions to correct for these effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ambient conditions (temperature, air pressure, humidity) are not compensated, then the measuring microscope operates with simple system design, but measurement precision deteriorates due to changes in optical path and magnification
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring ambient conditions (temperature, air pressure, humidity) using sensors and using this information to dynamically adjust measurement parameters. The system measures the actual ambient conditions, compares them to reference values, and applies compensation calculations to correct the optical path and magnification values, thereby maintaining high measurement precision despite environmental variations.
Solution Approach 2:
The patent applies parameter changes by introducing correction factors based on ambient condition variations. The system calculates deviation values for optical path and magnification based on measured ambient parameters (temperature, air pressure, humidity) and applies these corrections to the measurement results. This allows the system to adapt to changing environmental conditions without requiring physical modification of the optical system.
2Measurement precision
If reference measurement system is added to compensate ambient effects, then measurement accuracy improves, but device complexity increases due to additional sensors and correction mechanisms
Solution Approach 1:
The patent introduces an intermediary compensation system that acts as a mediator between the ambient environment and the measurement system. Instead of directly protecting the optical system from environmental changes, the system uses reference measurements from ambient sensors and applies computational corrections to the measurement data. This intermediary approach maintains measurement accuracy while avoiding the need for complex physical isolation or stabilization of the optical components.
3Reliability
If ambient condition compensation is implemented, then reliability of measurements improves under varying environmental conditions, but ease of operation deteriorates due to additional calibration and correction procedures
Solution Approach 1:
The patent implements self-service by enabling the measurement system to automatically compensate for ambient condition variations without requiring manual intervention. The system continuously monitors ambient parameters, automatically calculates correction factors, and applies these corrections to the measurement results in real-time. This self-service capability maintains high reliability under varying environmental conditions while minimizing the operational burden on the user, as the compensation occurs automatically during normal operation.
Data Source
AI summary
The invention relates to a method for capturing and compensating the influence of ambient conditions on an imaging scale (S) in a measuring microscope. Here, a modification of the optical properties in the measuring microscope that is caused by a change in the ambient conditions is measured by use of a reference measurement system, in particular an etalon, and, at the same time, an image of a reference structure with at least one reference length (L0) that is situated on a calibration mask is produced by use of a detector of the measuring microscope and a change (ΔL) of the reference length (L0) that is caused by the change in the ambient conditions is determined in the image of the reference structure. Subsequently, a correlation is established between the modification of the optical properties of the reference measurement system and the length change (ΔL) in the image, produced in the detector, of the reference structure of the calibration mask. This correlation can be used to carry out a computational adaptation of the size of picture elements of the detector and thus compensate the influence of ambient conditions on the imaging scale (S) of the measuring microscope.