Dynamic Pattern Generator for Reflection Electron Beam Lithography
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Solution Overview
Problem
Conventional electron beam direct write lithography is limited by low throughput due to its sequential, point-wise writing process, which is time-consuming, and electron beam projection lithography requires costly masks for each structure, making it uneconomical for small-scale production.
Innovation Solution
A maskless reflection electron beam lithography system that floods the wafer with a high beam current electron beam, partitioning it into independently controllable beams to achieve high-resolution writing across a large area, using a dynamic pattern generator with individually addressable pixel pads and a shadow mask to direct the beamlets onto the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electron beam direct write lithography is used, then high resolution can be attained, but the process is very time-consuming with low throughput
Solution Approach 1:
The invention segments the electron beam into multiple independent beamlets using a spatial light modulator (SLM) or digital micromirror device (DMD). Each beamlet can be independently controlled to write to different locations on the substrate simultaneously, transforming the sequential single-beam process into a parallel multi-beam process that maintains high resolution while dramatically increasing throughput
Solution Approach 2:
The invention employs dynamic control of the electron beam through programmable SLM/DMD devices that can rapidly reconfigure beam patterns. This dynamic capability allows the system to adapt beam shapes, positions, and intensities in real-time, enabling complex patterns to be written efficiently while maintaining the resolution benefits of focused electron beams
2Productivity
If electron beam projection lithography is used, then throughput is markedly higher, but costly masks are required for each structure
Solution Approach 1:
The invention uses programmable SLM/DMD devices as software-defined masks that can be digitally programmed with any desired pattern. This eliminates the need for physical masks, allowing rapid reconfiguration between different circuit designs without mask fabrication costs, while maintaining the high throughput of projection lithography
Solution Approach 2:
The invention changes the state of the patterning medium from fixed physical masks to dynamically controllable electronic displays. By modifying the electrical states of pixels in the SLM/DMD, different patterns can be generated without any physical changes to the system, enabling flexible, cost-effective production of custom circuits
3Device complexity
If a single electron beam is used for writing, then the system is simple, but the writing process is sequential and time-consuming
Solution Approach 1:
The invention segments a single electron beam into multiple beamlets using spatial modulation, enabling parallel writing to multiple locations simultaneously. This maintains the simplicity of using a single electron source while achieving the speed benefits of multiple beams through optical/electronic beam splitting and control
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 breaks the speed-versus-resolution tradeoff by enabling high-throughput, high-resolution writing on a large area with minimal electron-electron interactions, allowing for the simultaneous exposure of millions of pixels using a single column and electron source, reducing production time and costs.
Implementation Method 1
electrons are reflected from a first set of pixel pads of the dynamically patterned structure having a lower or more negative voltage level applied thereto and are absorbed or deflected from a second set of pixel pads of the dynamically patterned structure having a higher or more positive voltage level applied thereto
Data Source
AI summary
One embodiment relates to an apparatus of a dynamic pattern generator for reflection electron beam lithography. The apparatus includes a plurality of base electrodes in a two-dimensional array, an insulating border surrounding each base electrode so as to electrically isolate the base electrodes from each other; and a sidewall surrounding each base electrode. The sidewall comprises a plurality of stacked electrodes which are separated by insulating layers. In addition, the base electrodes are advantageously shaped so as to be concave. Furthermore, a conformal coating may be advantageously applied over the base electrodes and sidewalls. Another embodiment relates to an apparatus for reflection electron beam lithography. The apparatus includes a shadow mask configured to form an array of incident electron beamlets. The shadow mask comprises an array of holes which correspond one-to-one with an array of pixel pads of an electron reflective patterned structure. Other embodiments, aspects and features are disclosed.