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Immersion lithography conference highlights 32nm challenges |
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Oct 18, 2006 at 02:27 PM |
 At the 3rd International Symposium on Immersion Lithography, attendees were more than bullish on 193nm ArF immersion lithography being able to tackle volume production imaging tasks at the 45nm node. More than 20 percent of submitted papers dealt with immersion defects, highlighting the industry's momentum in preparing 193i for volume manufacturing at sub-65nm half-pitch.
However, attendees noted that breakthroughs in some critical areas would be required for single patterning using the immersion technique for use at the 32nm node. Currently, double patterning (DP) with immersion tools is the most likely practice at the 32nm node, which significantly adds to production costs and reduces lithography tool throughput.
"A path forward to half-pitch imaging below 40nm has been clearly identified, but our ability to get there will depend on how much progress we make in solving these critical issues," said Michael Lercel, SEMATECH's Lithography director. "We'll need to make strategic decisions on high-index materials, double patterning and double exposure to understand the ultimate extensibility of the technology into high-volume manufacturing."
Attendees highlighted five key areas that will need breakthroughs to prevent DP strategies being adopted at the 32nm node.
1. Development of high-index lens materials
2. Identification of high-index refractive fluids
3. Availability of effective photoresists (including leaching & high-index resists)
4. Cost-effective development of double exposure patterning
5. Attainment of low defectivity
Though the five key areas where not specifically ranked in any order, many lithography experts believe that a breakthrough in high-index refractive fluids dictates the ability to then push for higher NA of the optical systems, in turn allowing imaging at smaller feature sizes. Around 20 percent of the presentations were attributed to high-index fluids research. The Symposium was organized by Selete and SEMATECH in cooperation with IMEC. SEMATECH will organize a fourth international Symposium, aimed at accelerating decisions related to the identified critical issues, in the United States in October 2007.
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Lithography 
