Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Removal of imaged layers
Reexamination Certificate
2000-04-11
2001-08-07
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Removal of imaged layers
Reexamination Certificate
active
06270949
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the making of photolithographic masks for semiconductor manufacturing and particularly to semiconductor technologies having minimum dimensions of 0.25 microns and less. More particularly, the invention relates to methods of spray or puddle developing copolymer photoresists.
BACKGROUND OF THE INVENTION
In the manufacture of semiconductor devices, the ever present need to continue increasing of the density of image segments continually causes the seeking of new and more efficient techniques for processing semiconductor devices. The manufacture of semiconductor masks is no exception and the move to sub-0.25 micron technologies is imminent.
The instant invention relates to chain scission co-polymer photoresists of the type formed of 1:1 copolymerization of a-chloromethacrylate and a-methylstyrene, available as ZEP-nnn resists and available from Nippon Zeon, Japan. These resists are sensitive to light and e-beam exposure which makes them particularly useful in mask manufacture. Various compositions of resist are available based on their molecular weight. For example ZEP-520, having a molecular weight of about 50,000, or ZEP-7000, having a molecular weight of about 333,000. Once exposed, radiation sensitive portions of the copolymer are rendered soluble in organic solvents to produce good relief images.
A typical application would be to apply the resist in a solvent to a substrate, bake to remove the solvent, expose the resist via e-beam and then develop using a commercially supplied developer comprising one of the following developers, mixtures of diethyl ketone and diethyl malonate and single component solvents such as tolulene, xylene and alkyl esters of acetic acid such as amyl acetate or hexyl acetate. Following development, coated substrates are rinsed in a solvent such as 2-propanol.
SUMMARY OF THE INVENTION
When previously practiced methods were attempted to be implemented in the manufacture of semiconductor masks of the sub-0.25 micron range, nonuniform characteristics of the resulting photomasks were observed. This was particularly true for the Critical Dimension (CD) variation across a mask blank.
The particular resist development process used was that of a puddle, spray or combination of the two as opposed to a dip or tank process associated with the copolymer resist as described in the literature.
It has been discovered that the evaporative characteristics of the developer environment varied across the surface of the substrate, leading to non-uniform development due to varying concentration of reagents in the developer solution.
It is an object of the instant invention to provide an more uniform environment for the development of copolymer resists in order to provide more uniform and reproducible results in the critical dimensions.
In accordance with the invention an active developer which comprises a substantially non-volatile single component solvent is used for developing copolymer resists on semiconductor mask blanks. The preferred developer is ethyl 3-ethoxy propionate (EEP).
These and other objects of the invention will become more apparent when viewed in light of the following more particular description of the preferred embodiment of the invention.
REFERENCES:
patent: 3953265 (1976-04-01), Hood
patent: 4101397 (1978-07-01), Kotzsch et al.
patent: 4435575 (1984-03-01), Cainelli et al.
patent: 4454200 (1984-06-01), Bellott, Jr.
patent: 4456675 (1984-06-01), Anderson, Jr. et al.
patent: 4504007 (1985-03-01), Anderson, Jr. et al.
patent: 4943511 (1990-07-01), Lazarus et al.
patent: 4980269 (1990-12-01), Sakurai et al.
patent: 5091290 (1992-02-01), Rolfson
patent: 5354645 (1994-10-01), Schober et al.
patent: 5561194 (1996-10-01), Cornett et al.
patent: 5688628 (1997-11-01), Oie et al.
patent: 5733706 (1998-03-01), Sezi et al.
patent: 0 506 593 B1 (1998-07-01), None
patent: 55-140836A (1980-11-01), None
patent: 60-002946A (1985-01-01), None
Jpn. J. Appl. Phys. vol. 31 (1992) pp. 4508-4514, Part 1, No. 12B, Dec. 1992, Quantum Wire Fabrication by E-Beam Elithography Using High-Resolution and High-Sensitivity E-Beam Resist ZEP-520, Nishida et al.
Jpn. J. Appl. Phys. vol. 33 (1994) pp. 6919-6922, Part. 1, No. 12B, Dec. 1994, “Resist Performance in 5nm Soft X-Ray Projection Lithography”, Oizumi et al.
Jpn. J. Appl. Phys. vol. 34 (1995) pp. 6940-6946, Part 1, No. 12B, Dec. 1995, “An Electron Beam Nanolithography System and its Application to Si Nanofabrication”, Kurihara et al.
JPn. J. Appl. Phys. vol. 35 (1996) pp. 2385-2386, Part 1, No. 4A, Apr. 1996, “Sub-0.1um Patterning with High Aspect Ratio of 5 Achieved by Preventing Pattern Collapse”, Yamashita.
Jpn. J. Appl. Phys. vol. 35 (1996) pp. 4133-4137, Part 1. No. 7, Jul. 1996, “Down to 0.1 um Pattern Replication in Synchrotron Radiation Lithography,” Morigami et al.
J. Electrochem. Soc., vol. 144, No. 9, Sep. 1997, pp. 3169-3174, “Effect of Humidity on Photoresist Performance,” Bruce et al.
J. Vac. Sci. Technol. B 12(6), Nov./Dec. 1994, pp. 3280-3827, “Characterization of an expanded-field Schwarzschild Objective for extreme ultraviolet lithography”, Kubiak et al.
J. Vac. Sci. Technol. B 13(4), Jul./Aug. 1995, pp. 1473-1476, “Fabrication of sub-10-nm-silicon lines with minimum fluctuation,” Namatsu et al.
J. Vac. Sci. Technol. B 14(6), Nov./Dec. 1996, pp. 3829-3833, “High resolution electron beam lithography using ZEP-520 and KRS resists t low voltage”, Tanenbaum et al.
Microelectronic Engineering 27 (1995) pp. 71-74, “10-nm Silicon Lines Fabricated in (110) Silicon” Namatsu et al.
Microelectronic Engineering 27 (1995) pp. 317-320, Resist performance in 5nm and 13nm Soft X-ray Projection Lithography, Oizumi et al.
Microelectronic Engineering 30 (1996) pp. 419-422, “Nano-scale fluctuations in electron beam resist pattern evaluated by atomic force microscopy,” Nagase et al.
http://www.cnf.cornell.edu/SPIE/spie7.ht,m SPIE Handbook of Microlithograhy, Micromachining and Microfabrication, vol. 1: Microlithography.
Proc. SPIE—Int. Soc. Opt. Eng. (USA) vol. 2437 1995, p. 209-21, Army Res. Lab., Electron & Power Sources Directorate, Fort Monmouth, NJ, USA, “High energy (100 keV)e-beam lithography applied for fabrication of deep submicron SAW devices on lithium niobate and quartz,” Kondek et al.
Proceedings of the SPIE—The International Society for Optical Engineering, Proc. SPIE—Int. Soc. Opt. Eng. (USA) vol. 2512, p.21-7, “ZEP resist process for high accuracy photomask with a dry-etching capability”, Tarumoto et al.
http://www.zeon.co.ip/english
ew/f/f-tec4.html, “Future Challenges of Resist Materials for Mask Fabrication,” Kawata.
Manufacture's Product Literature, Oct. 15, 1996, Nippon Zeon Co., LTD, “Positive Electron Beam Resist ZEP810S ZEP7000 ZEP7000B”.
Chemical Data Sheets—Chemox Online, Benzyl Alchohol, Diethyl Ketone, Ethoxyethyl Acetate, Ethyl 3-ethoxypropionate, Hexyl Acetate, Octyl Acetate, Pentyl Acetate, Toluene, Xylene, P-Xylene.
Faure Thomas B.
Flanders Steven D.
Levin James P.
Linde Harold G.
Shepard Jeffrey F.
International Business Machines - Corporation
Le Hoa Van
Walter, Jr. Howard J.
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