Pulse Laser Recess Processing With Overlapping Irradiation Control
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Solution Overview
Problem
The resolution of semiconductor exposure apparatuses is compromised due to chromatic aberrations caused by the wide spectral linewidth of light emitted from KrF and ArF excimer laser apparatuses, leading to decreased resolution in projection lenses.
Innovation Solution
A laser processing method and system that utilize a gas laser apparatus to output pulse laser light, with a mover to adjust the radiation receiving region on the workpiece, and a processor to control the gas laser apparatus and mover to radiate pulse laser light to different processing regions, either sequentially or overlapping partially with previous radiation areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pulse laser light is continuously radiated to the same processing receiving region, then processing efficiency is improved, but the workpiece overheats and deforms
Solution Approach 1:
The processing receiving region is divided into multiple sub-regions, and the laser irradiation is segmented across these sub-regions. The mover shifts the radiation receiving region to irradiate different sub-regions sequentially, preventing concentration of thermal energy in one location while maintaining continuous processing.
Solution Approach 2:
The system dynamically shifts the radiation receiving region using a mover between laser pulses. This dynamic repositioning ensures that no single area receives continuous irradiation, allowing heat dissipation while maintaining processing continuity across the entire workpiece surface.
2Temperature
If the radiation receiving region is shifted to a completely new area for each pulse, then overheating is prevented, but processing time increases
Solution Approach 1:
The radiation receiving region is shifted only partially between pulses, creating overlapping irradiation zones. This partial shifting provides sufficient heat dissipation time while ensuring that adjacent areas are processed, reducing total processing time compared to complete repositioning.
Solution Approach 2:
The overlapping irradiation pattern ensures continuous coverage of the workpiece surface. By shifting the radiation receiving region partially rather than completely, the system maintains continuous processing action across the entire surface without idle time for full repositioning.
3Manufacturing precision
If the spectral linewidth of the laser light is narrowed to reduce chromatic aberrations, then resolution is improved, but the system complexity increases
Solution Approach 1:
The system changes the spatial parameter (position of radiation receiving region) instead of modifying the spectral parameter of the laser light. By shifting the irradiation position between pulses, the patent achieves processing quality without requiring spectral linewidth narrowing, thus avoiding additional optical components.
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 suppresses overheating and deformation of the workpiece by preventing continuous irradiation of the same processing region, thereby maintaining resolution and reducing processing time.
Implementation Method 1
forming plural recesses by radiating pulse laser light to plural processing receiving regions separate from each other on a surface of a workpiece
Data Source
AI summary
A laser processing method is a laser processing method for forming plural recesses by radiating pulse laser light to plural processing receiving regions separate from each other on a surface of a workpiece, the method including a first process of radiating the pulse laser light to a different one of the processing receiving regions on a pulse basis, and a second process of radiating the pulse laser light to a different one of the processing receiving regions on a pulse basis in such a way that the different processing receiving region overlaps with a part of a radiation receiving region irradiated with the pulse laser light in the first process.