Product Focus: Lithography
03/01/2008
Deep-UV coating capability
Deep-UV optical coating is now available that offers long-lifetime optics that address the growing need for highly accurate and reliable beam delivery in medical and semiconductor photolithography systems. Reflectivity and damage-threshold testing have been successfully completed. This company’s vertically integrated design-to-production facility includes in-house fabrication (shaping, grinding and polishing) and coating (deep-UV to near-IR) capabilities. Comprehensive metrology and use of the latest equipment to monitor and control pressure, temperature and rate ensure accurate and repeatable production processes. Agilent Technologies, Santa Clara, CA USA; www.agilent.com.
Scan-field i-line stepper
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The NSR-SF155 scan-field i-line stepper has improved throughput of 200 wafers per hour or more, with overlay accuracy reduced to less than 25nm. The system uses leading-edge lens technology to achieve the same wide exposure field as DUV scanners, making it good for mix-and-match applications. The stepper can be used for sub-critical layers in mass production of next-generation memory and microprocessor devices. Nikon’s NSR-SF150 uses Nikon’s Skyhook Technology to eliminate the influence of ground and stage vibrations, resulting in improved overlay accuracy. The NSR-SF155 further enhances overlay performance with new stage countermasses and improved temperature stabilization in the chamber. Users can upgrade their existing SF150 steppers to the SF155 configuration to gain improved throughput and overlay performance. Nikon Precision Inc., Belmont, CA USA; www.nikonprecision.com
Bilayer photoresist for sub-45nm DRAM production
This bilayer photoresist for DRAM production applications from TOK and Dow Corning uses a Dow Corning silicon polymer in the imaging layer to provide good etch selectivity. Adding the polymer to TOK’s photosensitive materials enables the use of thinner photoresist layers, which is claimed to improve pattern resolution and allows smaller circuit patterns to be transferred onto target wafers without pattern collapse issues. The new photoresist eliminates the hardmask layer and accompanying process steps required by multilayer photoresist processes. It can be used for both dry and immersion lithography. TOK has said that it has already demonstrated the use of the photoresist under immersion lithography conditions to produce 35nm line/space patterns. Applications include DRAM using both dry and immersion lithography for the 45nm node and beyond. Tokyo Ohka Kogyo Co. Ltd. (TOK) , www.tok.co.jp/en, and Dow Corning Electronics, www.dowcorning.com.