Inch by inch, EUVL is moving forward. The big problem is that it has not moved forward fast enough to be inserted confidently into any given future technology node. Although news from SEMATECH today touts ‘production-enabling breakthroughs’ being presented at the 2007 International EUVL Symposium, the press release lacks any mention of the timing for EUVL entering production! 

This has become a recurring theme in 2007 as EUVL was pushed out at the 32nm node at the SPIE Lithography conference in February this year, and no one has yet been brave enough to re-insert it at any future node with any conviction.

That aside, SEMATECH has listed the ‘breakthroughs,’ so we will have to see if this makes any difference to putting a ‘date’ on EUVL entering fabs.

Below is a sample of advances as revealed by SEMATECH technologists in papers that are being delivered at the symposium: 

• The best EUV mask blank defect density in the world today – 0.1 per cm² at 56nm resolution – will be reported by Chan-Uk Jeon, program manager of the Mask Blank Development Center in Albany, NY. SEMATECH also has created a detailed database of the source of the defects and is developing mitigation methods, such as smoothing, to reduce pit defects. (This SEMATECH smoothing process has achieved an 800X improvement in defect levels.) SEMATECH’s work will likely enable mask blanks to be ready for EUV beta tools in 2009.

• SEMATECH has achieved only five added defects at 56nm sensitivity in EUV mask blank defect totals, according to a paper by Patrick Kearney, Member Technical Staff. This milestone was enabled with industry-leading 56nm defect inspection sensitivity on multilayer coated blanks, and is rooted in SEMATECH’s strategy of collaborating with suppliers to bring together all elements of the industry.

• A manufacturable EUVL reticle solution also requires defect-free reticle handling. EUVL reticle protection using SEMATECH’s “sPod” design shows an average of less than one particle added per 100 separate reticle transfers, as explained in a paper by Long He, project engineer. Tests also show the sPod as a potential solution for shipping and storage.

• Using the industry’s best EUV resist exposure capability, SEMATECH has demonstrated that effective resolution down to 24nm can be achieved with current resists and optimized illumination conditions. These results are documented by Andy Ma, EUV resist bench project manager. Ma also describes remaining resist challenges, including linewidth roughness and photospeed.

• Current optical designs for EUV collectors are not very efficient, but SEMATECH has developed a series of upgrades that could boost collector efficiency by 2.8X. That would reduce the industry’s critical dependence on high-power sources or improve tool throughput and cost effectiveness. The designs are explained in a paper by Michael Goldstein, Senior Technologist.

• Detailed cost-of-ownership targets for EUVL – as determined by SEMATECH’s detailed cost models – will be reported by Phil Seidel, Senior Member Technical Staff.  These performance targets have been integrated into the consortium’s technology development projects, and show that the key elements for cost effective EUVL include source power, optics lifetime, and mask blank defect reduction.