Charged Particle Doublet Aperture Configuration for Lithography
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Solution Overview
Problem
Charged particle multi-beam lithography systems face low transmission efficiency due to the limited ability of beamlets to pass through narrow apertures, leading to wasted resources and increased exposure time.
Innovation Solution
The implementation of charged particle doublets with demagnifying capabilities and switchable blankers allows more charged particles to pass through by configuring the first aperture to be larger than the second aperture, increasing particle beam efficiency and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If narrow apertures are used in the electro-optical lens system, then the beamlets can be precisely directed to transfer the IC design pattern, but the transmission efficiency of the charged particle beam decreases significantly
Solution Approach 1:
The patent implements a nested aperture structure where a first aperture and a second aperture are positioned at different locations along the beam path. The first aperture has a larger size to allow high transmission efficiency, while the second aperture has a smaller size to provide precise beamlet direction control. The beam passes through the first aperture then the second aperture in sequence, achieving both high efficiency and precision through this nested arrangement.
2Productivity
If the first aperture is made larger to increase transmission efficiency, then more charged particles can pass through, but the beamlet size increases which may reduce pattern precision
Solution Approach 1:
The nested aperture structure allows the first aperture to be larger for high transmission while the second aperture acts as a constraint to define the final beamlet size. The sequential arrangement ensures that the beam is first allowed to pass through in large quantity, then shaped to the precise required dimensions by the second aperture.
Solution Approach 2:
The aperture system is segmented into two distinct stages: the first aperture handles the bulk transmission function, while the second aperture handles the precision shaping function. This segmentation of functions allows each aperture to be optimized for its specific purpose without compromise.
3Device complexity
If traditional single-aperture systems are used, then the system structure is simple, but the particle beam efficiency is low and exposure time is increased
Solution Approach 1:
The nested aperture structure, while adding a component, maintains relative structural simplicity by positioning the two apertures in sequence along the existing beam path. This linear addition integrates smoothly into the electro-optical lens system without requiring complex reconfiguration, yet delivers a 10-fold improvement in particle beam efficiency.
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 enhances particle beam efficiency by up to 10 times, reducing exposure time and energy requirements, thereby improving the overall performance and cost-effectiveness of the lithography system.
Implementation Method 1
The apparatus includes a plurality of charged particle doublets each having a first aperture and each configured to demagnify a beamlet incident upon the first aperture thereby producing a demagnified beamlet
Data Source
AI summary
A charged particle multi-beam lithography system includes an illumination sub-system that is configured to generate a charged particle beam; and multiple plates with a first aperture through the plates. The plates and the first aperture are configured to form a charged particle doublet. The system further includes a blanker having a second aperture whose footprint is smaller than that of the first aperture. The charged particle doublet is configured to demagnify a portion of the charged particle beam passing through the first aperture, thereby producing a demagnified beamlet. The blanker is configured to receive the demagnified beamlet from the charged particle doublet, and is further configured to conditionally allow the demagnified beamlet to travel along a desired path.