EUV Laser Pulse Energy Control via Segmented RF and Shutter Mechanisms
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Solution Overview
Problem
Current semiconductor production processes face challenges in generating extreme ultraviolet light with precise control over pulse energy, particularly for feature sizes below 32 nm, as existing EUV light generation systems struggle with dynamic range and exposure precision in microfabrication.
Innovation Solution
A laser apparatus and EUV light generation system that includes a seed laser device, a pulse energy adjusting unit, amplifiers, and a controller to vary pulse energy on a pulse-to-pulse basis and control excitation intensity, enabling both short-term and mid-to-long-term pulse energy control through an optical shutter and RF power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single control method is used for pulse energy, then the system structure is simple, but the dynamic range and exposure precision are insufficient for advanced microfabrication
Solution Approach 1:
The control system is segmented into two independent control mechanisms: (1) pulse energy adjusting unit with optical shutter for pulse-to-pulse energy control, and (2) RF power source for excitation intensity control across multiple pulses. This segmentation allows each subsystem to handle specific control ranges, achieving wide dynamic range without requiring a single complex control system.
Solution Approach 2:
The system implements dynamic control by allowing the pulse energy adjusting unit to vary transmission on a pulse-to-pulse basis while the RF power source adjusts excitation intensity for groups of pulses. This dynamic, multi-level control approach enables precise adaptation to different exposure requirements across varying production conditions.
2Reliability
If pulse energy is controlled on a pulse-to-pulse basis only, then short-term control is precise, but mid-to-long-term energy stability is compromised
Solution Approach 1:
The RF power source maintains continuous excitation intensity control across multiple pulses, ensuring mid-to-long-term pulse energy stability. Simultaneously, the pulse energy adjusting unit provides continuous pulse-to-pulse modulation capability. This dual continuous control ensures both short-term precision and long-term stability without interruption.
Solution Approach 2:
The controller receives feedback from both the pulse energy adjusting unit and RF power source to coordinate their operations. This feedback mechanism allows the system to maintain overall pulse energy stability while accommodating both pulse-to-pulse variations and multi-pulse excitation adjustments, resolving the conflict between stability and flexibility.
3Manufacturing precision
If existing EUV light generation systems are used, then the system is established and reliable, but dynamic range and exposure precision are insufficient for feature sizes below 32 nm
Solution Approach 1:
The system implements dynamic control by allowing the pulse energy adjusting unit to vary transmission on a pulse-to-pulse basis while the RF power source adjusts excitation intensity for groups of pulses. This dynamic, multi-level control approach enables precise adaptation to different exposure requirements across varying production conditions, providing the adaptability needed for advanced microfabrication.
Solution Approach 2:
The system changes key operational parameters by introducing dual control mechanisms that independently adjust pulse energy (via optical shutter transmission) and excitation intensity (via RF power). This parameter control enables the system to adapt to different feature sizes and exposure requirements, achieving the manufacturing precision required for sub-32 nm fabrication.
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 allows for precise control of EUV light pulse energy, enhancing exposure precision and dynamic range, thereby supporting advanced microfabrication requirements for feature sizes below 32 nm.
Implementation Method 1
at least one amplifier for amplifying the pulse laser beam; at least one power source for varying an excitation intensity in the at least one amplifier
Implementation Method 2
a pulse energy adjusting unit configured to vary pulse energy of the pulse laser beam
Implementation Method 3
a Laser Produced Plasma (LPP) type apparatus in which plasma generated by irradiating a target material with a laser beam is used
Data Source
AI summary
A laser apparatus may include a seed laser device configured to output a pulse laser beam, a pulse energy adjusting unit configured to vary pulse energy of the pulse laser beam, at least one amplifier for amplifying the pulse laser beam, at least one power source for varying an excitation intensity in the at least one amplifier, and a controller configured to control the pulse energy adjusting unit on a pulse-to-pulse basis for the pulse laser beam passing therethrough and to control the at least one power source for a group of multiple pulses of the pulse laser beam.