Objective Lens Arrangement With Proximity Sensing for Thermal Focus Drift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical microlithography systems face challenges in maintaining focus accuracy due to thermal instabilities affecting projection optics, leading to degradation of performance and focal plane drift.
Innovation Solution
An objective lens arrangement with a proximity sensor attached to the final optical component, allowing real-time detection and compensation for thermal-induced changes in the spatial position of the projection optics, maintaining a stable working distance and focal plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If projection optics components are used without thermal compensation, then device complexity is reduced, but focus accuracy degrades due to thermal instabilities
Solution Approach 1:
A sensor is integrated into the objective lens to detect thermal changes in real-time, providing feedback signals that are processed to determine thermal expansion amounts. This feedback mechanism enables dynamic compensation of thermal instabilities, maintaining focus accuracy without requiring complex external measurement and adjustment systems.
Solution Approach 2:
The objective lens performs self-diagnosis and self-compensation for thermal effects. The integrated sensor monitors the lens's own thermal state, and the system automatically adjusts focus parameters based on detected thermal expansion, eliminating the need for separate thermal management subsystems.
2Measurement precision
If sensor head is mechanically attached at final optical component, then measurement precision of thermal changes is improved, but device complexity increases
Solution Approach 1:
The sensor head is mechanically integrated directly into the final optical component of the objective lens, merging the measurement function with the optical system. This integration allows the sensor to directly measure thermal changes at the critical focal point without requiring separate mounting structures or additional alignment mechanisms.
3Measurement precision
If real-time thermal compensation is implemented, then focus accuracy is maintained, but ease of operation decreases
Solution Approach 1:
The system automatically performs thermal compensation without requiring user intervention. The integrated sensor continuously monitors thermal changes, the processing unit calculates expansion amounts, and the focus position is automatically adjusted, making the complex thermal management transparent to the operator.
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
Enhances focus accuracy and performance by dynamically adjusting the spatial position of the projection optics to counteract thermal instabilities, ensuring precise focus control during lithographic processes.
Implementation Method 1
account for the influence of thermal instabilities or temperature changes on the projection optics
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The present disclosure provides an objective lens arrangement (100) for projection of an optical beam. The objective lens arrangement comprises an objective lens (110) comprising a final optical component (112) configured to focus the optical beam onto a substrate (122). The objective lens arrangement further comprises a proximity sensor (130) comprising a sensor head (132), the sensor head being arranged between the objective lens and the substrate, and a processing unit (140). The processing unit is configured to determine a first distance (d1) between the sensor head and a surface of the substrate based on an input from the proximity sensor. The sensor head is mechanically attached at the final optical component.