Dual-Grating Measurement System for Lithography Position Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In lithography processes for manufacturing electronic devices, the precision position control of substrates relative to projection optical systems is hindered by air fluctuations due to long optical paths in existing encoder systems, particularly when using optical interferometers.
Innovation Solution
A movable body apparatus with a dual-grating measurement system and a control system that uses multiple heads to irradiate grating areas, allowing for precise position measurement and correction, thereby reducing the influence of air fluctuations and improving position control accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical interferometer system is used to obtain position information on the substrate, then measurement precision can be achieved, but the long optical path makes the system vulnerable to air fluctuation influences
Solution Approach 1:
The patent divides the measurement system into multiple independent measurement components (first measurement system with first grating member and first heads, second measurement system with second grating member and second heads). Each component measures position information independently over shorter optical paths, reducing the cumulative effect of air fluctuations while maintaining overall measurement precision through integration of multiple measurements.
2Manufacturing precision
If multiple heads irradiate multiple grating areas to measure position information, then position control accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple measurement systems (first and second measurement systems) with multiple heads and grating members into a unified position measurement apparatus. The control system integrates data from all heads and grating areas to calculate comprehensive position information, achieving high precision position control while managing system complexity through coordinated operation of merged components.
Solution Approach 2:
The control system receives position information from multiple heads irradiating multiple grating areas, processes this feedback data, and uses it to control the substrate's position with high precision. The system continuously monitors and adjusts based on the combined measurements, improving manufacturing precision through feedback control.
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 the precision of substrate position control within the lithography process, leading to improved exposure accuracy and reliability in manufacturing electronic devices like liquid crystal displays and semiconductor devices.
Implementation Method 1
the first grating member including measurement components in the first direction and the second direction
Implementation Method 2
in the case of obtaining position information on the substrate using an optical interferometer system
Implementation Method 3
the second grating member including measurement components in the first direction and the second direction
Implementation Method 4
the second measurement system measuring position information on the second movable body in the second direction
Data Source
AI summary
A movable body apparatus includes: a substrate holder which can move in the X-axis and Y-axis directions; a Y coarse movement stage which can move in the Y-axis direction; a first measurement system which acquires position information on the substrate holder by heads on the substrate holder and a scale on the Y coarse movement stage; a second measurement system which acquires position information on the Y coarse movement stage by heads on the Y coarse movement stage and a scale; and a control system which controls the position of the substrate holder based on position information acquired by the first and second measurement systems. The first measurement system irradiates a measurement beam while moving the heads in the X-axis direction with respect to the scale, and the second measurement system irradiates a measurement beam while moving the heads in the Y-axis direction with respect to the scale.