Canon Extends Lithography Roadmap: Presents Resolution Capabilities Beyond k1 of 0.25 at BACUS; Presents Innovative Mask and Imaging Methods for Contact/Via and k1 Extension.

Business Editors/High-Tech Writers

SAN JOSE, Calif.--(BUSINESS WIRE)--Sept. 4, 2003

The Semiconductor Equipment Division of Canon U.S.A. Inc., a subsidiary of Canon Inc. (NYSE: CAJ), will present two papers at the 23rd Annual BACUS Symposium on Photomask Technology next week in Monterey, Calif. The papers highlight Canon's recent technology innovations enabling customers to accelerate process development and significantly extend the capability of DUV lithography.

During the conference, Canon will explore the vortex mask, with results shown to print sub-100 nm contacts using KrF lithography. The company will also present innovative optical extension technologies - also referred to as resolution enhancement technologies (RET) - applied to address new resolution challenges.

The further extendibility of optical lithography using KrF and ArF exposure tools is currently being investigated. In fact, it may be in greater demand now as a result of unforeseen issues, increased cost and the general difficulty of next-generation lithography (NGL) tools and processes.

"In order for the industry to keep pace with the ITRS roadmap, current lithography technologies must be extended well beyond normal limits," stated Tommy Oga, National Applications engineering manager of Canon U.S.A. "Current roadmap barriers, such as contact/via printing and dense pitch patterns below 70 nm using KrF, require innovative and integrated solutions and are key to Canon's optics forever strategy."

Canon proposes practical two-mask, double exposure schemes for doubling resolution in future lithography. The company has demonstrated a 70 nm L/S pattern (140 nm pitch) or smaller by using a NA 0.68 KrF scanner, which corresponds to kpitch = 0.38 (k1=0.19). For customers, this results in an extended tool set lifetime, as well as the ability to attain smaller geometries more cost-effectively because of an accelerated process development. Furthermore, eliminating tool qualification and the sales process leads to early return on investment.

Canon also says vortex masks will print the smallest vias with the tightest pitches, thus creating smaller geometries compared to current processes. The vortex mask adds a phase shift mask application, which is also used to extend a customer's existing tool set.

Vortex Via Validation Abstract:

The first vortex masks composed of rectangles with phases of 0(degree), 90(degree), 180(degree) and 270(degree) - as proposed at Photomask 2002 - have been fabricated and shown to print sub-100 nm contacts. The walls of the phase trenches are very nearly vertical, with all four-phase regions meeting at sharp corners, which define the phase singularities. Arrays with pitches down to 210 nm have been printed in negative DUV resist using KrF illumination with NA=0.73 and (sigma)=0.15. The developed contacts are somewhat elliptical, but their shapes can be corrected (if necessary) by OPC techniques. The depth of focus for +/-10% CD variation is >400 nm for 85 nm CD vias at 210 nm pitch and >700 nm for 100nm vias at 250 nm pitch. The exposure latitude is ~15% at best focus. At constant exposure dose, the via CDs vary with pitch as predicted by simulations. Increasing exposure dose makes the openings smaller, more uniform and more circular. No significant surface development has appeared due to phase-edge printing. However, the space-width alternation phenomenon familiar from linear chromeless phase-edge lithography does cause small positional errors for vortex vias, and each of the four vortices in the repeating pattern behaves somewhat differently through focus, potentially limiting the common process window.

Beyond k1=0.25 Lithography (70nm L/S Patterning Using KrF Scanners) Abstract:

In this paper, we propose practical two mask - double exposure schemes for doubling resolution in future lithography. One method uses Si-bilayer resist, and the other method uses an advanced film process (hard mask). The basic idea of both methods are similar: The first exposure forms 1:3 ratio L/S patterns in one resist/hard mask layer, then the second exposure images 1:3 ratio L/S pattern in-between the two lines (in the spaces) that are already formed by the first exposure. In conjunction with these two exposure, in theory, kpitch=0.25 pattern can be made. In this paper, we will demonstrate 70nm L/S pattern (140nm pitch) or smaller by using a NA0.68 KrF Scanner, which corresponds to kpitch = 0.38 (k1=0.19). We will also investigate the critical alignment and CD controls issues for these two-mask, dual-exposure schemes.

About Canon

The Semiconductor Equipment Division of Canon U.S.A. supplies step-and-repeat and step-and-scan photolithography tools and solutions used in the design and fabrication of semiconductor devices, flat panel displays, microelectromechanical systems (MEMS) and read/write heads for magnetic storage systems.

Canon U.S.A., Inc. delivers consumer, business-to-business, and industrial imaging solutions. In 2001, the Company was listed as one of Fortune's Most Admired Companies in America, and was ranked Number 41 on the Business Week list of "Top 100 Brands." Its parent company, Canon, Inc. (NYSE:CAJ) is a top patent-holder of technology, ranking third overall in the U.S. in 2001, with global revenues of $22 billion. Canon U.S.A. employs approximately 11,000 people at over 30 locations. For more information, visit www.usa.canon.com.