EUVL Focus

Monthly Archives: February 2013

Further comments on physics and engineering of EUV sources

I got good bit of feedback on my last blog in which I discussed the differences between physics and engineering of EUV Sources, and the implications of that difference. I was glad to see that it generated some re-evaluation of current thinking (as intended) and now would like to clarify few points.
First is the supplier commitment. One can have lots of great technical options backed by beautiful physics, but if there are no suppliers to turn ideas into commercial products, technology will go nowhere. EUV source technology will succeed as it has three large suppliers, each with current business experience in supplying light sources for scanners.  In the end, we may not have this many suppliers due to business and/or technology consolidation, but right now we do. For EUV sources for metrology, there is an even larger number of potential suppliers who are working to find a way to meet industry requirements. With this backing and competition among suppliers to outperform one another, we ought to see success.
The real question is whether scanners that can produce ~40 wafers per hour (WPH), which  I expect to be ready by 2014, will deliver cost of ownership (COO) sufficient to convince leading chip-makers to switch from 193nm based technology. The challenge is to estimate the point where the COO of EUVL will cross that of 193nm, making it more cost effective technology. Will it be at 15nm or 7nm? What product, what wafer size?  I do not have sufficient information to make this prediction right now, but I expect some acceptance of EUVL in high volume manufacturing (HVM) by the end of 2014.
Just because a technology cannot scale up in power does not mean that it will poorly serve EUVL in the process of development. Last week I gave an example of synchrotrons. They have provided low throughput printing to support development of current EUVL technology, and will continue to do so for future versions of EUVL. So let us continue that very wise investment! Supplier Energetiq has 10W source technology that has aided EUVL very well so far. Present designs may not scale up to the required brightness for mask defect metrology tools, but this supplier is looking at new physics for scaling, as they demonstrated in the last two Source Workshops in Dublin.
So it is a matter of realizing what cannot be done with present physics, and finding new ways to achieve scaling. We have seen >5% conversion efficiency and high debris mitigation techniques at low rep rates. Let us see how far these approaches can scale up. If they do not (over a reasonable period), then we need to quickly pick up another potential solution from a host of possibilities. These will become available to us if we continue to look for new physics, including development of new materials and chemistry. We can research the physics of EUVL with a very tiny fraction of what we have spent on engineering development of the technology. I still believe in the power of innovation and competition to help us move forward, but for this effort we must engage universities, national labs and independent research organizations to generate new ideas leading to new solutions. Only then will we be in a position to solve the persistent problem of low throughput in EUVL scanners.