Lithographic Support Structure Control via Dual Coordinate Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lithographic apparatuses face challenges in maintaining alignment accuracy due to mechanical vibrations caused by high-speed movements, which affect the positioning of substrates and masks, leading to insufficient relative position stability and increased overlay errors during the lithography process.
Innovation Solution
A control system comprising a first measurement system, a second measurement system, and a controller that measures and converts positions between different coordinate systems to accurately position support structures and aerial images, compensating for position errors and stabilizing the alignment of substrates and masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed movements are used to increase productivity, then productivity is improved, but mechanical vibrations increase causing positioning accuracy to deteriorate
Solution Approach 1:
The positioning system is divided into two independent measurement systems: a first measurement system for measuring object position and a second measurement system for measuring support structure position. This segmentation allows each system to optimize for its specific function, with the second system specifically dedicated to detecting vibrations and position errors of the support structure during high-speed operations.
Solution Approach 2:
The controller receives position error signals from both measurement systems and uses feedback control to adjust the support structure position. The second measurement system continuously monitors the support structure position and feeds back position error signals to the controller, which then adjusts actuators to compensate for vibrations and maintain positioning accuracy during high-speed movements.
2Manufacturing precision
If coordinate system transformations are implemented to improve positioning accuracy, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The controller acts as an intermediary that performs coordinate system transformations between the first measurement system coordinate system and the second measurement system coordinate system. Rather than making the measurement systems themselves complex, the transformation logic is centralized in the controller, which converts position data from the first measurement system into the coordinate system of the second measurement system for accurate comparison and error calculation.
Data Source
AI summary
A control system controls a support structure of a lithographic apparatus. A first measurement system measures the position of a substrate supported by the support structure, in a first coordinate system. A second measurement system measures the position of the support structure in a second coordinate system, the first measurement system having a presumed position in the second coordinate system. A controller controls the position of the support structure based on measurements by the second measurement system, to convert the measured position of the substrate into a converted position of the support structure in the second coordinate system, to position the support structure based on the converted position, to receive a position error signal indicative of a difference between the presumed position and an actual position of the first measurement system in the second coordinate system, and to position the support structure dependent upon the position error signal.