Integrated Circuit Manufacturing Through Multi-Droplet EUV Plasma Generation
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Solution Overview
Problem
Existing EUV lithography systems face inefficiencies in producing extreme ultraviolet radiation using laser-produced plasma sources, necessitating improvements in resolution and energy transfer to smaller droplets for enhanced EUV radiation generation.
Innovation Solution
The method involves generating multiple parallel laser fringes to ionize smaller droplets simultaneously, increasing the surface area and interaction time, thereby enhancing the efficiency of EUV radiation production by distributing laser energy across multiple droplets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high-power laser beam is focused on a single droplet target to produce EUV radiation, then the energy concentration is high, but the overall EUV radiation output and efficiency are limited
Solution Approach 1:
The invention divides the single droplet target into multiple smaller droplet targets arranged in an array. The laser beam is correspondingly divided into multiple sub-beams that simultaneously irradiate each droplet. This segmentation increases the total surface area for laser-droplet interaction, thereby enhancing EUV radiation output while using smaller droplets that can be more efficiently vaporized and ionized.
Solution Approach 2:
The invention transitions from a single-point laser-droplet interaction to a distributed array configuration. Multiple droplets are arranged in a two-dimensional array, and the laser beam is divided into multiple sub-beams that illuminate different droplets simultaneously. This dimensional expansion from 0D (single point) to 2D (array) significantly increases the total interaction area and EUV radiation throughput.
2Loss of energy
If the laser beam is divided into multiple sub-beams to irradiate multiple droplets, then the energy distribution is optimized, but the system complexity increases
Solution Approach 1:
The invention introduces a beam-splitting optical system as an intermediary component that divides the single high-power laser beam into multiple sub-beams. This intermediary device enables efficient energy distribution to multiple droplets while maintaining centralized laser source control. The optical intermediaries (beam splitters, mirrors, lenses) manage the complexity by providing a systematic way to distribute energy without requiring multiple independent laser sources.
Solution Approach 2:
The optical system components serve multiple functions: the beam-splitting optics not only divide the laser beam but also can be configured to control the spatial arrangement of sub-beams, adjust intensity distribution, and synchronize with droplet ejection timing. This multi-functionality reduces the need for additional specialized components, managing system complexity while achieving optimized energy transfer.
3Productivity
If smaller droplets are used as targets, then the vaporization and ionization efficiency is improved, but the total target mass available for EUV generation is reduced
Solution Approach 1:
The invention segments the total target mass into multiple smaller droplets arranged in an array. While each individual droplet is smaller and vaporizes more efficiently, the collective array maintains sufficient total mass. The segmentation enables simultaneous irradiation of multiple droplets, increasing the rate of EUV photon generation while each small droplet's rapid vaporization ensures complete energy conversion and high emission efficiency.
Solution Approach 2:
The invention implements continuous droplet ejection and laser irradiation, where droplets are continuously supplied to replace those that have been vaporized. This continuous action ensures that the total mass of target material is continuously replenished, maintaining sustained EUV radiation output. The high-speed droplet ejection system delivers fresh droplets at rates matching the vaporization consumption, ensuring uninterrupted high-efficiency EUV generation.
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 increases the efficiency of EUV radiation generation by optimizing energy transfer to smaller droplets, leading to improved lithography processes with higher resolution and reduced energy requirements.
Implementation Method 1
a high-power laser beam is focused on small droplet targets of metal, such as tin, to form a highly ionized plasma that emits EUV radiation
Implementation Method 2
to form a highly ionized plasma that emits EUV radiation
Implementation Method 3
dividing and interfering a laser beam to produce a plurality of parallel fringes
Data Source
AI summary
A method for generating an extreme ultraviolet (EUV) radiation includes simultaneously irradiating two or more target droplets with laser light in an EUV radiation source apparatus to produce EUV radiation and collecting and directing the EUV radiation produced from the two or more target droplet by an imaging mirror.