Excimer Laser Wavelength Detection with Dual-Housing Temperature Control
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Solution Overview
Problem
Chromatic aberration in semiconductor exposure apparatuses due to the large spectral line width of KrF and ArF excimer laser devices leads to reduced resolution, necessitating line-narrowed laser devices with etalons, but ambient temperature changes cause wavelength drift, affecting measurement accuracy.
Innovation Solution
A wavelength detection device with a first and second housing, each equipped with heaters and temperature control processors, to maintain constant temperatures of etalons and optical systems, reducing temperature variations and drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a line narrowing module including etalon is provided in the laser resonator to narrow the spectral line width, then chromatic aberration is reduced and resolution is improved, but wavelength drift occurs due to ambient temperature changes affecting measurement accuracy
Solution Approach 1:
The patent applies parameter changes by actively controlling the temperature of the etalon housing to compensate for ambient temperature variations. The temperature control unit adjusts the etalon temperature to maintain optimal wavelength measurement conditions, thereby preventing wavelength drift while preserving the resolution improvement achieved through line narrowing.
Solution Approach 2:
The patent implements feedback control through temperature sensors that continuously monitor the etalon housing temperature and feed this information back to the temperature control unit. This closed-loop feedback system automatically adjusts heating or cooling to maintain stable etalon temperature, eliminating wavelength drift caused by ambient temperature changes while preserving the chromatic aberration correction benefits.
2Manufacturing precision
If the spectral line width is narrowed using etalon in the laser resonator, then chromatic aberration is minimized, but the device complexity increases due to additional temperature control mechanisms
Solution Approach 1:
The patent merges the temperature control functions for the etalon housing with the existing laser resonator control system. By integrating the temperature control unit and temperature sensors into the overall laser system architecture, the patent reduces operational complexity while maintaining the resolution improvements achieved through line narrowing with etalon.
Solution Approach 2:
The patent implements self-service through automatic temperature control where the system autonomously maintains optimal etalon temperature without requiring manual intervention. The temperature control unit automatically adjusts heating or cooling based on sensor feedback, eliminating the need for complex manual temperature management while preserving the chromatic aberration correction benefits.
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 solution effectively suppresses wavelength drift, enhancing measurement accuracy and stability, thereby improving the resolution of semiconductor exposure apparatuses.
Implementation Method 1
a first heater arranged on an outer wall of the first housing, and configured to heat the first housing; a second heater arranged on an outer wall of the second housing, and configured to heat the second housing
Implementation Method 2
a line narrowing module (LNM) including a line narrowing element (etalon, grating, and the like) is provided in a laser resonator of the gas laser device to line-narrow a spectral line width
Implementation Method 3
a first light concentrating optical system configured to cause light output from the first etalon to be imaged on a first sensor
Data Source
AI summary
A wavelength detection device for an excimer laser includes a first housing accommodating a first etalon; a first heater arranged on an outer wall of the first housing, and configured to heat the first housing; a second housing connected to the first housing, and accommodating a first light concentrating optical system configured to cause light output from the first etalon to be imaged on a first sensor; a second heater arranged on an outer wall of the second housing, and configured to heat the second housing; and a processor configured to control a temperature of the first housing and a temperature of the second housing using the first heater and the second heater.