Lithographic Apparatus Thermo-Mechanical Deformation Control
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Solution Overview
Problem
Current lithographic apparatuses face challenges in accurately assessing and compensating for pattern deformations caused by mechanical stresses and thermal effects, such as non-uniform temperature distributions, which can lead to mismatches between consecutively applied patterns.
Innovation Solution
A control system is implemented in the lithographic apparatus to receive pattern and radiation data, determine the dissipation distribution of the pattern using a thermo-mechanical model, and generate control signals to adjust components of the apparatus, thereby mitigating pattern deformations and ensuring accurate pattern projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If infrared temperature sensors are used to measure temperature at various locations on the patterning device, then temperature measurement capability is provided, but the accuracy of deformation assessment remains insufficient
Solution Approach 1:
A computational model acts as an intermediary between temperature measurements and deformation assessment. The model processes temperature data from sensors and converts it into deformation predictions, enabling accurate deformation assessment without direct mechanical measurement of the pattern itself.
Solution Approach 2:
Direct mechanical measurement of pattern deformation is replaced by a computational approach. The system uses temperature sensors combined with a thermo-mechanical model to calculate deformation, substituting complex mechanical measurement systems with a more accurate computational model.
2Productivity
If the pattern is exposed to radiation beam to transfer design pattern to substrate, then pattern transfer function is achieved, but pattern deformation occurs due to thermal effects
Solution Approach 1:
The system performs preliminary calculation of thermal effects and pattern deformation before the actual pattern transfer process. By predicting deformation in advance using the computational model, the system can pre-compensate for expected distortions, ensuring accurate pattern transfer.
Solution Approach 2:
The system establishes a feedback loop where temperature measurements during exposure are fed into the computational model to continuously monitor and adjust for pattern deformation. This real-time feedback enables dynamic compensation for thermal effects throughout the exposure process.
3Manufacturing precision
If compensation measures are taken to correct pattern deformation, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The computational model serves multiple functions: it processes temperature sensor data, calculates thermal effects, predicts pattern deformation, and provides compensation guidance. This multi-functionality consolidates what would otherwise require multiple separate systems into a single integrated computational platform.
Solution Approach 2:
The system uses its own temperature sensor measurements and computational model to automatically calculate and compensate for deformations. This self-service capability eliminates the need for external intervention or complex manual adjustment mechanisms, reducing overall system complexity.
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
This solution enables more accurate assessment and compensation of pattern deformations, improving the alignment and focusing of patterns on substrates, leading to enhanced manufacturing precision.
Implementation Method 1
determine a dissipation distribution of the pattern based on the pattern data and the radiation data, determine a deformation of the pattern by applying the dissipation distribution in a thermo-mechanical model of the patterning device
Data Source
AI summary
An apparatus including an illumination system to condition a radiation beam, a support to support a patterning device, the patterning device capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam, a substrate table constructed to hold a substrate, a projection system to project the patterned radiation beam onto a target portion of the substrate, and a control system configured to: receive pattern data characterizing a pattern distribution, receive radiation data characterizing the radiation beam, determine a dissipation distribution of the pattern based on the pattern data and the radiation data, determine deformation of the pattern by applying the dissipation distribution in a thermo-mechanical model of the patterning device, and determine a control signal to control a component of the apparatus based on the deformation of the pattern.