Exposure Laser Wavelength Control for Mixed-Pattern Focus Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor exposure systems, the wide spectrum line width of gas lasers like KrF and ArF excimer lasers leads to chromatic aberration, reducing resolving power, and existing solutions like line narrowing modules are insufficient to completely eliminate this issue, affecting the focus positions of different patterns on a reticle.
Innovation Solution
A system that calculates and adjusts the wavelength of a pulse laser beam to minimize the dispersion of best focus positions across multiple patterns on a reticle, using a processor to determine the optimal wavelength for scanning exposure, thereby reducing inter-pattern best focus differences and improving critical dimension uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a line narrowing module is provided in the laser resonator to narrow the spectrum line width, then chromatic aberration is reduced, but the device complexity increases
Solution Approach 1:
The patent changes the wavelength parameter of the laser beam dynamically to minimize dispersion of best focus positions for different patterns. By adjusting the wavelength based on pattern combinations, the system achieves minimum dispersion without requiring additional optical components, thus resolving the contradiction between manufacturing precision and device complexity
Solution Approach 2:
The system dynamically adjusts the laser wavelength during exposure operations based on the patterns being exposed. This dynamic parameter adjustment allows the system to optimize focus for different pattern combinations in real-time, achieving high manufacturing precision without the need for static additional optical components
2Manufacturing precision
If the wavelength of the laser beam is adjusted to minimize dispersion of best focus positions, then critical dimension uniformity is improved, but the control complexity increases
Solution Approach 1:
The system uses feedback from pattern combination information to automatically determine and adjust the optimal wavelength. The control unit receives information about which patterns will be exposed together and automatically selects the wavelength that minimizes dispersion, providing intuitive control while achieving high critical dimension uniformity
Solution Approach 2:
The system automatically determines the optimal wavelength based on the pattern combinations without requiring manual intervention. The control unit self-adjusts the wavelength parameter based on the exposure requirements, reducing the burden on operators while maintaining high manufacturing precision
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 approach effectively reduces inter-pattern best focus differences and enhances critical dimension uniformity by optimizing the wavelength of the pulse laser beam, leading to improved focus accuracy and reduced variability in pattern formation during semiconductor manufacturing.
Implementation Method 1
irradiating a reticle with a pulse laser beam
Implementation Method 2
an illumination optical system through which the pulse laser beam is guided to the reticle
Data Source
AI summary
An exposure system that performs scanning exposure of a semiconductor substrate by irradiating a reticle with a pulse laser beam includes a laser apparatus configured to emit a pulse laser beam, an illumination optical system through which the pulse laser beam is guided to the reticle, a reticle stage, and a processor configured to control emission of the pulse laser beam from the laser apparatus and movement of the reticle by the reticle stage. The reticle includes a region in which multiple kinds of patterns are arranged in a mixed manner in a scanning width direction orthogonal to a scanning direction of the scanning exposure. The processor instructs the laser apparatus about a target wavelength such that the laser apparatus emits the pulse laser beam of a wavelength with which dispersion of best focus positions corresponding to respective patterns of the multiple kinds of patterns is minimum.