Powerlase has made significant steps forward in developing reliable and cost-effective, kilowatt-class laser modules with short pulse duration and small footprint, for use as EUV drivers. These characteristics in parallel to EUV target requirements are essential for the generation of 115W of in-band EUV power at the intermediate focus. These laser modules can be coupled to the EUV target by using our flexible spatial and temporal multiplexing approach in order to scale up the laser average power on target. The multiplexing method developed by Powerlase is modular and optimised for maximum EUV collection angle. To further this goal we are currently evaluating target materials such as xenon in various phases and forms and also have a programme in place to investigate suitable tin targets.
Powerlase has made significant advances towards making the LPP EUV source the most likely choice for a full production EUV lithography machine. Our main achievement was enhancing the performance of the LPP driver and particularly increasing the average power per laser module. This was achieved by increasing the electrical to optical conversion efficiency of our gain modules. In order to increase the conversion efficiency of the in-band EUV, we are currently using cryogenic solid xenon, as well as other target materials. The combination of an efficient and cost effective laser driver with appropriate choice of target material significantly lowers the Cost of Ownership (CoO) of the LPP EUV source, including day to day running, making it comparable to the cost of Discharge Produced Plasma (DPP) sources.
We have recently made significant advances in the performance of our laser driver module employed in our laser produced plasma (LPP) EUV source. We increased the average power output from the laser whilst minimising the overall Cost of Ownership (CoO) and footprint of the system. In addition to minimising the CoO of the laser solution, it is necessary to choose an appropriate target that can attain the overall requirements of EUVL. We are currently investigating xenon in its various phases, as well as other target materials, in order to increase the conversion efficiency of the source and therefore further drive down its CoO. We have prepared a source roadmap in response to industry demands, and it shows that the combination of our demonstrated laser technology with available targets will meet the objectives for a production level source.
Electrical to EUV conversion efficiency is a key parameter for systems scaled to EUV emission in the 100W regime. Improvement in efficiency of conversion from laser radiation at the EUV source, reduces the required laser power and as such can lend itself to reduced heat load and debris emission. Also, improvement in the electrical to laser conversion efficiency results in a direct reduction in cost of ownership. Laser solutions optimised for efficient conversion to high M<SUP>2</SUP> CW laser radiation are not optimised in design for efficient short-pulsed operation; the mode of operation required for EUV generation. Aspects of both EUV source and laser design are discussed, with a view to optimising conversion efficiency for scalable EUV solutions.