Beyond direct-write: Dynamically reconfigurable holographic multibeam interference lithography for high-throughput nanomanufacturing

Lead Research Organisation: University of Cambridge
Department Name: Engineering

Abstract

When manufacturing any kind of electronic device, patterning is required to achieve small features, such as different regions of materials with different functions. The ever-increasing complexity of modern electronics and photonics has led to a plethora of approaches to substrate patterning. For each of these approaches, there are always compromises between the speed of patterning (write speed), the minimum feature size, versatility and cost.

The most dominant patterning process in electronics and photonics manufacturing is mask-based photolithography. Here, the chip to be patterned is coated with a light-sensitive material known as a "resist," and light is shone onto the resist through a mask with deliberately placed holes. Light that passes through the holes causes a chemical change in the resist, and thus the pattern is transferred from the mask onto the chip. The disadvantage is that each photolithography mask is only suitable for a one particular type of chip design and cannot be reconfigured for the manufacture of other chip designs, and mask design and fabrication is time-consuming and costly. Alternative patterning techniques, known as direct-write lithography, do enable great flexibility in device design, but at the expense of slow patterning speeds, and often large capital and operating costs.

Here, we propose a novel process for photolithography, which we name holographic multi-beam interference lithography (HMBIL). HMBIL promises large area patterning with sub-wavelength resolution as well as fast write speeds, short development times, low costs and a dynamically reconfigurable choice of exposure pattern. Using HMBIL, we will demonstrate patterning of arbitrarily-shaped 100 nm feature sizes over large areas with high throughput (>25 cm^2 device area in under 1 hour), which is currently unachievable with direct-write lithography techniques.

As a proof-of-principle, we will demonstrate the capability of HMBIL for manufacturing an example device structure: multispectral filter arrays. These filter arrays, when integrated with an image sensor, will allow the acquisition of light spectra for applications as diverse as medical imaging to remote sensing. HMBIL manufacture of multispectral filter arrays will open up a range of avenues for custom detectors and imaging sensors for security, industrial or medical applications.

We envisage this versatile new HMBIL process primarily in two locations in the manufacturing chain: Firstly, as a means of rapid prototyping of nanofabricated designs and secondly, as a means of large scale production of individually customised components. This will revolutionise manufacturing processes across a broad range of application areas including miniaturised optoelectronics, versatile point-of-care diagnostic devices, displays and image sensors, on-chip photonics (waveguides and photonic crystals), plasmonics, nano/micro-electromechanical machines, microfluidics, embedded systems and the internet of things, and many more.

Publications

10 25 50
 
Description We have demonstrated the patterning of metasurfaces using our new lithography technique.
Exploitation Route This new capability could increase the throughput of electronics and optics manufacturing.
Sectors Electronics

Manufacturing

including Industrial Biotechology

 
Description Ernest Oppenheimer Early Career Fellowship
Amount £400,000 (GBP)
Organisation University of Cambridge 
Sector Academic/University
Country United Kingdom
Start 09/2023 
End 09/2026
 
Title HoloGen: An open-source toolbox for high-speed hologram generation 
Description The rise of virtual and augmented reality systems has prompted an increase in interest in the fields of 2D and 3D computer-generated holography (CGH). The numerical processing required to generate a hologram is high and requires significant domain expertise. This has historically slowed the adoption of CGH in emerging fields. In this paper we introduce HoloGen, an open-source Cuda C and C++ framework for computer-generated holography. HoloGen unites, for the first time, a wide array of existing hologram generation algorithms with state of the art performance while attempting to remain intuitive and easy to use. This is enabled by a IC# and Windows Presentation Framework (WPF) graphical user interface (GUI). A novel reflection based parameter hierarchy is used to ensure ease of modification. Extensive use of C++ templates based on the Standard Template Library (STL), compile time flexibility is preserved while maintaining runtime performance. The current release of HoloGen unites implementations of well known generation algorithms including Gerchberg-Saxton (GS), Liu-Taghizadeh (LT), direct search (DS), simulated annealing (SA) and one-step phase-retrieval (OSPR) with less known specialist variants including weighted GS and Adaptive OSPR. Benchmarking results are presented for several key algorithms. The software is freely available under an MIT license. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
URL https://data.mendeley.com/datasets/nzk4swwsrg
 
Title HoloGen: An open-source toolbox for high-speed hologram generation 
Description The rise of virtual and augmented reality systems has prompted an increase in interest in the fields of 2D and 3D computer-generated holography (CGH). The numerical processing required to generate a hologram is high and requires significant domain expertise. This has historically slowed the adoption of CGH in emerging fields. In this paper we introduce HoloGen, an open-source Cuda C and C++ framework for computer-generated holography. HoloGen unites, for the first time, a wide array of existing hologram generation algorithms with state of the art performance while attempting to remain intuitive and easy to use. This is enabled by a IC# and Windows Presentation Framework (WPF) graphical user interface (GUI). A novel reflection based parameter hierarchy is used to ensure ease of modification. Extensive use of C++ templates based on the Standard Template Library (STL), compile time flexibility is preserved while maintaining runtime performance. The current release of HoloGen unites implementations of well known generation algorithms including Gerchberg-Saxton (GS), Liu-Taghizadeh (LT), direct search (DS), simulated annealing (SA) and one-step phase-retrieval (OSPR) with less known specialist variants including weighted GS and Adaptive OSPR. Benchmarking results are presented for several key algorithms. The software is freely available under an MIT license. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
URL https://data.mendeley.com/datasets/nzk4swwsrg/1
 
Title Research data supporting "Automated Computer Vision-Enabled Manufacturing of Nanowire Devices" 
Description Figure2c,e: Detected spatial distribution, length and orientation of isolated InAs nanowires in a 1 × 1 mm^2 region. Figure 4: Transfer characteristics of automatically fabricated nanowire devices with (a) 0.5 µm channel length, (b) 1.0 µm channel length, (c) 2.0 µm channel length, and (d) 2.5 µm channel length at source-drain voltage VDS = 10 mV. (e) Statistical data of nanowire device misalignment measured from the center of the nanowire to the center of the electrode pattern. Statistical data of (f) on/off ratio, (g) peak current, and (h) threshold voltage measured in automatically fabricated nanowire devices. Figure S8: Statistical data of (a) mobility and (b) hysteresis measured in automatically fabricated nanowire devices. 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
Impact This dataset describes the output of the first system capable of identifying nanowires and routing electrodes automatically. This automation has reduced the time for each device iteration from months to days. 
URL https://www.repository.cam.ac.uk/handle/1810/341921
 
Description Plessey - Micro-LED manufacturing 
Organisation Plessey Semiconductors Ltd
Country United Kingdom 
Sector Private 
PI Contribution Information provided on our lithography technique and its applicability to micro-LED manufacturing.
Collaborator Contribution Information provided on Plessey's designs and criteria.
Impact Outcomes and outputs pending.
Start Year 2021
 
Description Engineering Open Day 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact Around 60 secondary school pupils attended the very first Open Day held in our Electrical Engineering Building, where our team presented a demonstration of the system developed in this project, and a poster.
Year(s) Of Engagement Activity 2023