Nonlinear Crystal Switching for Narrow-Linewidth Exposure Lasers
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Solution Overview
Problem
Current semiconductor exposure technologies face challenges in achieving high resolution due to chromatic aberrations caused by the wide spectral linewidth of KrF and ArF excimer laser apparatuses, which are exacerbated by liquid-immersion exposure methods, leading to decreased resolution and efficiency in manufacturing electronic devices.
Innovation Solution
A solid-state laser system is developed that includes a wavelength conversion system with nonlinear crystals and a gas handling system, allowing for the generation and amplification of excimer laser light with a narrowed spectral width, which is then used in a semiconductor exposure apparatus to improve resolution and reduce chromatic aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If liquid-immersion exposure is used to improve resolution, then the apparent wavelength of light shortens, but chromatic aberrations increase due to the wide spectral linewidth of excimer laser apparatuses
Solution Approach 1:
The patent applies parameter changes by narrowing the spectral linewidth of the excimer laser from its natural wide range (350-400 pm) to a much narrower range. This is achieved through a line narrowing module containing an etalon or grating that selectively transmits a narrow bandwidth of laser light, thereby reducing chromatic aberrations while maintaining the resolution benefits of liquid-immersion exposure
2Manufacturing precision
If the spectral linewidth of the excimer laser is narrowed to reduce chromatic aberrations, then resolution improves, but the device complexity increases due to the need for a line narrowing module
Solution Approach 1:
The patent introduces an intermediary element (the line narrowing module with etalon or grating) that mediates between the wide-spectrum excimer laser source and the exposure system. This intermediary component filters the laser spectrum to achieve narrow linewidth without requiring a complete redesign of the laser source itself, thus managing the complexity trade-off
3Adaptability or versatility
If KrF or ArF excimer laser apparatuses are used as light sources, then exposure capability is provided, but chromatic aberrations occur due to wide spectral linewidth ranging from 350 to 400 pm
Solution Approach 1:
The patent maintains the versatility of KrF or ArF excimer laser apparatuses as light sources while changing the spectral parameter by introducing a line narrowing module. This module reduces the spectral linewidth from 350-400 pm to a narrow bandwidth, thereby eliminating chromatic aberrations while preserving the exposure capability of these established laser sources
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
The system effectively generates excimer laser light with a narrowed spectral width, enhancing the resolution and reducing chromatic aberrations in semiconductor exposure, thereby improving the manufacturing efficiency of electronic devices.
Implementation Method 1
a wavelength conversion system with nonlinear crystals... allowing for the generation and amplification of excimer laser light with a narrowed spectral width
Implementation Method 2
a first heater configured to heat the first nonlinear crystal, a second heater configured to heat the second nonlinear crystal
Implementation Method 3
a first gas introduction tube via which a first gas is introduced into the first container, a second gas introduction tube via which the first gas is introduced into the second container
Data Source
AI summary
In a laser system according to an aspect of the present disclosure, the following components are disposed: a first container that accommodates a first heater and a first crystal holder holding a first nonlinear crystal and includes a first light incident window via which laser light is incident and a first light exit window via which the laser light exits; a second container that accommodates a second heater and a second crystal holder holding a second nonlinear crystal and includes a second light incident window via which the laser light is incident and a second light exit window via which the laser light exits; and a stage that holds the first and second containers. A controller controls the stage to move the first nonlinear crystal away from the optical path of the laser light and inserts the second nonlinear crystal into the optical path of the laser light.