Deep UV Optical Isolator Using Stress Birefringence for Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laser processing systems using excimer lasers for semiconductor exposure face challenges with chromatic aberration due to wide spectral linewidths, which can decrease resolution and limit the effectiveness of deep ultraviolet laser processing.
Innovation Solution
The system incorporates a laser apparatus that outputs a deep ultraviolet laser beam, an optical isolator with a polarizer and a deep ultraviolet light transmitting element, and a piezoelectric element connected to the transmitting element. A processor supplies a drive signal to the piezoelectric element, allowing the deep ultraviolet light transmitting element to function as a ¼ wave plate through stress birefringence, thereby reducing chromatic aberration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a projection lens is formed of a material that transmits ultraviolet light, then chromatic aberration occurs due to wide spectral linewidths, but using materials that block UV light prevents chromatic aberration
Solution Approach 1:
The patent applies dynamics by making the optical isolator's wave plate function dynamically controllable through piezoelectric actuation. The stress applied to the quartz plate can be adjusted in real-time to optimize the ¼ wave plate function for different wavelengths, thereby dynamically compensating for chromatic aberration while maintaining high resolution UV processing capability
Solution Approach 2:
The patent changes the physical parameters of the optical isolator by applying stress to the quartz plate through piezoelectric elements. This stress modulation alters the birefringence characteristics of the quartz, enabling it to function as a ¼ wave plate that compensates for chromatic aberration across the UV spectrum while maintaining transmission efficiency
2Manufacturing precision
If conventional optical isolators are used with deep ultraviolet light, then chromatic aberration decreases resolution, but adding a line narrowing module increases device complexity
Solution Approach 1:
The patent achieves multi-functionality by designing an optical isolator that simultaneously provides isolation functionality and chromatic aberration compensation. The quartz plate with piezoelectric actuation serves dual purposes: maintaining the isolator's primary function while actively compensating for chromatic aberration, thereby eliminating the need for separate line narrowing modules
Solution Approach 2:
The patent introduces the quartz plate with piezoelectric actuation as an intermediary element between the UV light source and the projection lens. This intermediary actively compensates for chromatic aberration through stress-induced birefringence modulation, serving as a mediator that resolves the contradiction between resolution and device complexity
3Manufacturing precision
If the spectral linewidth of the laser beam is narrowed, then chromatic aberration is reduced, but the device complexity increases due to the line narrowing module
Solution Approach 1:
Instead of narrowing the spectral linewidth through complex optical filtering, the patent changes the optical parameters of the existing UV light by applying stress to the quartz plate. This stress modulation alters the phase retardation characteristics, enabling chromatic aberration compensation without requiring line narrowing modules or spectral filtering
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 configuration enhances the durability of the optical isolator against deep ultraviolet light and improves the resolution of the laser processing system by minimizing chromatic aberration, enabling more precise processing of semiconductor materials.
Implementation Method 1
a piezoelectric element connected to the deep ultraviolet light transmitting element. A processor supplies, to the piezoelectric element, a drive signal having a voltage changeable with a natural frequency of the deep ultraviolet light transmitting element, and to transmit the light emission trigger signal to the laser apparatus using the natural frequency or a frequency obtained by dividing the natural frequency as a repetition frequency so that the deep ultraviolet light transmitting element functions as a 1/4 wave plate by stress birefringence generated in response to force applied from the piezoelectric element
Implementation Method 2
the deep ultraviolet light transmitting element functions as a 1/4 wave plate by stress birefringence generated in response to force applied from the piezoelectric element
Data Source
AI summary
A laser processing system includes a laser apparatus that outputs a deep ultraviolet laser beam in response to a light emission trigger signal, an optical isolator including a polarizer, a deep ultraviolet light transmitting element, and a piezoelectric element connected to the deep ultraviolet light transmitting element, and a processor that supplies, to the piezoelectric element, a drive signal having a voltage changeable with a natural frequency of the deep ultraviolet light transmitting element, and transmits the light emission trigger signal to the laser apparatus using the natural frequency or a frequency obtained by dividing the natural frequency as a repetition frequency so that the deep ultraviolet light transmitting element functions as a ¼ wave plate by stress birefringence due to force from the piezoelectric element, and processing is performed by irradiating a workpiece with the laser beam from the optical isolator.