Galvanometric Laser Scanning for Faster Recess Processing
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Solution Overview
Problem
Existing semiconductor exposure apparatuses face challenges in maintaining resolution due to chromatic aberrations caused by wide spectral linewidths of KrF and ArF excimer laser light, which necessitates the use of line narrowing modules to reduce spectral linewidth.
Innovation Solution
A laser processing system that includes a gas laser apparatus outputting pulse laser light, a mover to move the radiation receiving region on the workpiece, and a first galvanometric scanner to change the optical path of the pulse laser light, allowing for precise movement and overlap of the radiation receiving region to form plural recesses on the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stage is used to move the workpiece between processing receiving regions, then the workpiece can be positioned accurately, but the processing period becomes long due to slow movement speed
Solution Approach 1:
The patent replaces the mechanical stage movement system with an optical beam deflection system using galvanometric scanners. Instead of physically moving the heavy workpiece via mechanical stage, the laser beam is rapidly redirected to different processing regions, achieving both fast response and precise positioning without mechanical inertia limitations
Solution Approach 2:
The patent divides the workpiece processing into multiple processing receiving regions that can be independently targeted. The laser beam is segmented in its action path, jumping between discrete regions (first, second, third processing receiving regions) rather than continuously scanning, enabling rapid switching and parallel processing potential
2Device complexity
If the spectral linewidth of laser light is wide, then the laser apparatus can operate simpler, but chromatic aberrations occur in the projection lens reducing resolution
Solution Approach 1:
The patent introduces a line narrowing module as an intermediary component in the laser resonator. This module (containing etalons or gratings) acts as a mediator that selectively transmits specific wavelengths while blocking others, thereby narrowing the spectral linewidth and reducing chromatic aberrations without fundamentally changing the laser gain medium or overall laser architecture
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 shortens the processing period by allowing the galvanometric scanner to move the radiation receiving region more quickly between processing receiving regions, compared to relying solely on the stage to move the workpiece.
Implementation Method 1
a gas laser apparatus configured to output pulse laser light
Implementation Method 2
a first galvanometric scanner configured to change an optical path of the pulse laser light
Implementation Method 3
forming plural recesses by radiating pulse laser light to plural processing receiving regions
Data Source
AI summary
A laser processing system for forming recesses by radiating pulse laser light to processing receiving regions separate from each other in a first direction on a surface of a workpiece includes a gas laser apparatus that outputs the pulse laser light, a mover that moves a radiation receiving region on the surface that is irradiated with the pulse laser light in the first direction, and a first galvanometric scanner that changes the optical path of the pulse laser light to move the radiation receiving region in the first direction. The mover moves the radiation receiving region such that the moved radiation receiving region overlaps with a part of the radiation receiving region irradiated immediately before. The first galvanometric scanner moves the radiation receiving region such that the moved radiation receiving region is located within the processing receiving region different from the processing receiving region irradiated immediately before.