Manufacturing with Light - photochemical ALD to manufacture functional thin films

The purpose of this project is to develop a novel photochemical ALD manufacturing technology. Conventional atomic layer deposition is already widely used in the displays and microelectronics industries. It is a thermo-chemical process where two precursor reagents are pulsed in cycles onto a heated work piece. The combination of the substrate temperature and the chemical reaction energy drive the process forward to deposit the thin film layer by layer. Because the process occurs on the surface, highly uniform and conformal layers can be deposited onto high-aspect ratio or porous materials with ultra-precise thickness control. In this project, we propose to develop a UV photochemical ALD process. The purpose of this is to reduce the dependence of the process on thermal energy. We will use an existing ALD reactor at Liverpool and incorporate into it a switchable UV lamp source. This will be configured so that it can expose the separate gas-phase precursors or on the surface as adsorbates. The wavelength of the output will be tuned to photo-chemically decompose the precursors to form the film. In the second stage of the project we will investigate selective deposition or 'writing' of ALD films. We'll do this using a near field approach with a lithographic plate and secondly by incorporating a TI DLP chip into the optical train just above the work piece. Both of these approaches will enable us to expose adsorbates on the surface selectively and explore the prospect of patterning ALD films. If successful, the project establish the feasibility of a new process technology to extend ALD the other industry sectors, such as roll-to-roll barrier layers; plastic electronics; organic - inorganic PV; biomedical instruments and others.

This project will have direct impact on the world-wide research and development of ALD technology. The development of ALD manufacturing technology has been driven by advancements in the IC electronics sector over the last decade. The global ALD market is $0.5bn and is forecast to reach $1.8bn by 2016 [1]. This comprises 40% of materials and 60% of equipment sales. The current trend is now to diversification across other manufacturing sectors. The proposed project will make a significant contribution to enabling ultrathin film manufacturing by enabling direct-write patterning and lower temperature processing.

The project partners span the supply chain for ALD manufacturing, staring with precursor materials; partnerships with ALD equipment manufacturers; and OEM producers delivering products in plastic electronics, biomedical devices, optics and energy. One of our industrial collaborators SAFC Hitech, specialises in organometallics manufacturer, will supply a range of precursor chemicals. The Liverpool University group and SAFC Hitech have a long-term collaboration in this field. The research has the potential to put the UK at the forefront of a crucial emerging area of new materials and precursors, which is likely to impact on the global economy as well as on the UK and European economy. The Centre for Process Innovation's (CPI) Printable Electronics Centre focuses on design, development and prototyping for the emerging printable electronics industry. CPI is currently developing an ALD roll-2-roll ALD facility Beneq, which will have the potential to assess the developments proposed here. Qioptiq is the UK's leading high performance optics manufacturer and our world leading position has been achieved and secured through continuous advancement of technologies and significantly in the area of thin-film coatings to meet a variety of optical and environmental requirements. Nanoco is unique in the nanomaterials market as a company that manufacture large quantities of quantum dots to develop a wide variety of next-generation products, particularly in the fields of electronics, lighting, biomedical and PV solar cells. Victrex plc, a leading global manufacturer of high performance polymers, comprises two divisions: Victrex Polymer Solutions that focuses on transport, industrial and the electronics markets and Invibio Biomaterial Solutions that focuses on providing specialist solutions for medical device manufacturers.

The potential impact of this project will be the development of a new photochemical manufacturing process technology, which will have applications across a broad range of manufacturing sectors in the UK. The impact in terms of new materials, chemistry, products and processes will be significant if the project is successful.

[1] Annina Titoff, Editor in Chief "ALD Pulse" (2013)