Laser Induced Micro Plasma Processing (LIMP2)

Micromachining materials such as ceramics and polymers for use in the medical implant or electronics industry is becoming an increasingly important activity for UK industry. Creating features on the micron scale or depositing coatings on the nanoscale has enabled the above industrial sectors to develop new solutions to such applications as: the acceptance of implants by the human body or patterning of thin conduction layers on touch-screen displays at a high resolution, allowing the phone's owner to watch movies while travelling.
All of these breakthroughs in medical devices and microelectronics, are made possible by the creation of small features. Laser Induced Micro Plasma Processing (LIMP2) will be an enabling tool allowing the production of features smaller than the actual laser spot which can be as less than 10 um. LIMP2 would also allow lasers to be used on materials that up to now have been impossible to machine by laser.
The aim of the project is to develop an understanding of how a plasma, a highly energetic hot gas, and laser beam interact at the surface of different substrates such as polymers, glass, metals and ceramics. It will attempt to answer such questions as "Can we control the plasma-laser beam interaction using electrical and magnetic fields and in so doing create interesting effects that will allow the plasma to be pinched into an area that is smaller than the laser spot diameter"? In so doing LIMP2 will allow a relative inexpensive laser system to machine directly on the nanoscale.
LIMP2 will introduce a new manufacturing technology that will be employed in the manufacturing of high value high performance electronic goods. This will benefit the UK suppliers of laser sources into the electronics production machine market. The other benefit that the general public will see in terms of healthcare. An important application in the medical field is microstructure texturing of medical implants such as stents and artificial joints. LIMP2 can be used to create novel microstructures that have the property of being able to control how a living cell interacts with the surface of the implant. The structures will allow one type of cell to grow while suppressing other types that would prove detrimental to the patient's health, causing swelling of a joint and possible rejection of the implant.
The UK companies who are supporting the project will also gain immediate benefits from a successful conclusion of the project. Two laser companies are working together to support the project, one based in the Midlands the other in the South West of England. LIMP2 would open new markets for their laser systems allowing them to compete in the competitive microelectronics market in the Far East.
Two of the projects supporting companies Biomer Technology and MicroSystems plan to use LIMP2 in medical devices market but on very different materials. Biomer Technology produces a polymeric coating that they use to coat medical devices. Biomer is interested in LIMP2 micro-machined surfaces that can control cell growth. MicroSystems on the other hand produce micro-moulds for major pharmaceutical companies. MicroSystems see LIMP2 being used on their micro-moulds to produce surfaces that are hydrophilic, (likes water) or hydrophobic, repels water molecules. This type of control over a surface property is very useful not only in the medical device sector but in other sectors such as aerospace, electronics, and the defence industry.

The impact of LIMP2 can be divided into two areas, impact within the LIMP2 consortium in terms of economic and social impact such as wealth and job creation. The second area is those outside the consortium such as other end users involved in micromachining.
Fianium: LIMP2 will help strengthen Fianium through laser system sales into applications that are at present beyond the processing capability of their traditional picosecond laser systems. Fianium specialising in picoseconds laser systems they are looking to expand their market into other sectors in both Europe and the US. The medical device market looks especially lucrative, but the difficulty at present is that the Fianium laser system produce only small pulse energy systems and combined with the poor absorption of polymers at 1064nm both of these factors are making it difficult to exploit this market. LIMP2 impact by combining both laser beam and plasma in polymer processing would open the medical device market and allow Fianium to complete with traditional laser processing in the green and UV in terms of both processing quality and the price of the system. The benefits for Fianium would be in the creation of extra jobs and an increase in profitability.
Another potentially important application where LIMP2 could produce major benefits for Fianium is in the processing of thin films. Synergy exists between both Fianium and another consortium member Oxford Lasers with respect to this application. Germany are at present investing in solar cell technology and a big application for lasers will be in scribing thin coatings so isolating areas of conducting tracks. Film thicknesses greater than twenty microns could prove problematical for the Fianium system. LIMP2 impact for Fianium with respect to this application will be in allowing thicker film processing and reducing cycle times. This could have an important impact on earning foreign exchange for the UK in what is primary a Germany market supplied by German laser companies.

GSI Group: The benefit for this company will be extending their knowledge in hybrid laser processing. LIMP2 will be timely for GSI as they have purchase of a number of US laser manufacturers who produce micromachining laser systems. LIMP2 will be the first micro hybrid laser processing application. The impact will be first felt in the application group at Rugby with dissemination to the other US based companies through Rugby hub and the Photonics in Engineering Group (PiE) at LJMU. Though LIMP2 was initially aimed at the picosecond laser system of Fianium, GSI have recognised the potential impact LIMP2 could have with respect to micromachining with nanosecond laser pulses and potential lucrative markets in the plasma screen and photovoltaic cell production in the Far East and as such have given LIMP2 their full support.

Oxford Lasers: LIMP2 could have a major impact for one of Oxford Laser ongoing European research programmes, that of laser material processing of thin films. A description of the actual film is prohibited due to NDA but the performance of a picosecond laser system would be enhanced by LIMP2 hybrid processing. These results could be easily translated to other application where a thin coating needed to be machined on a substrate.

Biomer Technology Ltd: Biomer and the PiE group have a close working relationship. In collaboration with Biomer and the University of Liverpool LIMP2 will be introduced onto a project looking at the control of stem cells using surface topography. Also in parallel with this activity working with bio interests based within GERI, LIMP2 will be used to surface texture a polymer substrate supplied by Biomer that will be used in a coated stent application. The project will look at using surface texturing to control the growth rate of smooth muscle and endothelial cells. If this proves possible then the benefits to Biomer would be significant. Wider impact will be covered in the pathways document.