TREA

Removal of CMP residue from semiconductor substrate using supercritical carbon dioxide process

Follow

Information

  • Patent Grant
  • 6537916
  • Patent Number
    6,537,916
  • Date Filed
    Thursday, October 18, 2001
    23 years ago
  • Date Issued
    Tuesday, March 25, 2003
    21 years ago
Information
Abstract
A method of removing Chemical Mechanical Polishing (CMP) residue from a semiconductor substrate is disclosed. The semiconductor substrate with the CMP residue on a surface is placed within a pressure chamber. The pressure chamber is then pressurized. Supercritical carbon dioxide and a solvent are introduced into the pressure chamber. The supercritical carbon dioxide and the chemical are maintained in contact with the semiconductor substrate until the CMP residue is removed from the semiconductor substrate. The pressure chamber is then flushed and vented.
Description




FIELD OF THE INVENTION




The present invention relates to the field of removing Chemical Mechanical Polishing (CMP) residue from semiconductor wafers. More particularly, the present invention relates to the field of removing CMP residue from semiconductor wafers using supercritical carbon dioxide.




BACKGROUND OF THE INVENTION




Manufacture of semiconductor devices commonly employ a Chemical Mechanical Polishing (CMP) process to planarize a wafer surface. The CMP process removes top surface layers from a semiconductor wafer. The CMP process leaves a CMP residue of CMP chemicals and particles that is difficult and problematic to remove by current post-CMP cleaning methods. It is well known that the CMP residue predominantly remains in surface features on the wafer surface.




The current post-CMP cleaning methods require that the wafer surface be mechanically washed or brushed by a commercially available machine called a scrubber. The scrubber may employ heat or ultrasonic augmentation and typically requires immersion times of two to twenty minutes to achieve complete removal of the CMP residue from the wafer surface. Because the wafer surface is mechanically washed or brushed by the scrubber, the scrubber leaves defects or scratches in the wafer surface.




It is well known that, if some of the CMP residue remains in the surface features, performance of the semiconductor devices will be degraded. Additionally, it is well known that the cost of manufacturing a wafer of the semiconductor devices is proportional to the time employed for each processing step.




It would be advantageous to be able to remove the CMP residue without using the mechanical washing or brushing employed by the scrubber in order to reduce an amount of the defects and the scratches. Further, it would be advantageous to more effectively remove the CMP residue from the surface features on the wafer surface.




What is needed is a method of removing the CMP residue that does not use the mechanical washing or brushing.




What is further needed is a method of removing the CMP residue that is more effective than the mechanical washing or brushing in removing the CMP residue from the surface features.




What is additionally needed is a method of removing the CMP residue that is more efficient than the scrubber.




SUMMARY OF THE INVENTION




The present invention is a method of removing Chemical Mechanical Polishing (CMP) residue from a surface of a semiconductor substrate. The semiconductor substrate, including the CMP residue on the surface, is placed within a pressure chamber. The pressure chamber is then pressurized. Supercritical carbon dioxide and a solvent are introduced into the pressure chamber. The supercritical carbon dioxide and the solvent are maintained in contact with the semiconductor substrate until the CMP residue is removed from the semiconductor substrate. The pressure chamber is then flushed and vented.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a flow chart illustrating the steps of a method of the present invention.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT




The present invention utilizes high solvency and cleaning characteristics of supercritical carbon dioxide to assist in a post-CMP cleaning process. In the preferred embodiment, a small amount of a chemical, i.e., a solvent or a solvent mixture, is added to affect the post-CMP cleaning process as compared to the prior art. In the present invention, the supercritical carbon dioxide carries a small amount of the chemical to a wafer surface to be cleaned and is then recycled back to a carbon dioxide compressor for reuse.




The chemical is soluble or insoluble in carbon dioxide and is not damaging to semiconductor device materials. The high solvency and solubilizing ability of the supercritical carbon dioxide makes this method fast, safe, and very quick. High turbulence at wafer surface features in conjunction with hyper-efficient mass transport of a chemical co-solvent package can clean the wafer surface in less than five minutes. CMP residue of CMP chemicals and abrasive particles is effectively removed without direct mechanical contact, in contrast to current methods. Another advantage of the present invention is that the wafer surface contains fewer defects as compared to mechanical scrubber methods.




The solvency of supercritical carbon dioxide increases with pressure. Diffusivity and viscosity at or above a critical point of carbon dioxide remains similar to that of a gas phase. Because density above the critical point of the carbon dioxide is nearly equal to that of a liquid state, the supercritical carbon dioxide carries the chemical onto the wafer surface and cleans sub-micron surface features of a modern semiconductor device. In the present invention, the supercritical carbon dioxide also functions to carry away the CMP residue, including the CMP chemicals and abrasive particles, from the sub-micron surface features of the modern semiconductor device. Thus, a small amount of the chemical mixed with the supercritical carbon dioxide performs the post-CMP cleaning process and also cleans away any remaining unwanted chemicals and the CMP residue.




The preferred embodiment of the post-CMP cleaning process of the present invention is illustrated in FIG.


1


. The semiconductor wafer including the CMP residue is placed in a pressure chamber in a first process step


20


. The pressure chamber is then sealed and pressurized with the carbon dioxide, in a second process step


22


. As the pressure inside the pressure chamber builds, the carbon dioxide becomes liquid and then reaches supercritical temperature and pressure. Typical conditions for this process range from 20 to 70° C. and 1050 and 6000 psig. When the desired conditions are reached, a small amount of the chemical is introduced into a supercritical carbon dioxide stream and thus added into the pressure chamber to begin cleaning, in a third process step


24


. Typical types and amounts of chemicals are:


















a.




0.1-15.0 v/v % of isopropyl alcohol and related alcohols;






b.




0.1-15.0 v/v % of propylene carbonate and related carbonates;






c.




0.1-15.0 v/v % of ethylene glycol and related glycols;






d.




0.001-5.0 v/v % of ozone;






e.




0.1-15.0 v/v % of hydrogen fluoride and related fluorides;






f.




0.1-15.0 v/v % of ammonium hydroxide and related hydroxides;






g.




0.1-15.0 v/v % of citric acid and related acids; and






h.




0.1-15.0 v/v % of a mixture of any of the above chemicals.














The chemical is preferably selected from a preferred group including the isopropyl alcohol, the propylene carbonate, the ethylene glycol, the ozone, the hydrogen fluoride, the ammonium hydroxide, and the citric acid, or a mixture thereof.




The chemical is alternatively selected from an alternative group including the alcohols related to the isopropyl alcohol, the carbonates related to the propylene carbonate, the glycols related to the ethylene glycol, the fluorides related to the hydrogen fluoride, the hydroxides related to the ammonium hydroxide, and the acids related to the citric acid, or a mixture selected from these chemicals and the preferred group.




The post-CMP cleaning process continues with recirculation of the supercritical carbon dioxide and with mixing, i.e., agitating, thereof inside the pressure chamber until the CMP residue is removed, typically from one-half to five minutes, in a fourth process step


26


. The pressure chamber is then flushed with pure supercritical carbon dioxide or liquid carbon dioxide to remove all traces of any remaining chemicals, in a fifth process step


28


. Finally, the chamber is vented to atmosphere and the wafer is removed, in a sixth process step


30


. At this point, an optional rinse in DI (deionized) or ultra pure water may be performed to finish the cleaning process.




The present invention uses the supercritical carbon dioxide in combination with the small amount of a chemical admixture to remove the CMP residue from the surfaces of the semiconductor devices in a post-CMP cleaning system. The post-CMP cleaning system includes a wafer process chamber, a pump, a sensor system, a pressure and flow regulating system, and a recovery chamber. The wafer process chamber holds the semiconductor wafer or semiconductor wafers. The pump is capable of compressing liquid carbon dioxide beyond the critical point. The sensor system measures temperature, pressure and flows. The pressure and flow regulating system connects a carbon dioxide source to the wafer chamber at the desired conditions. The recovery chamber collects solid and liquid material exhausted from the wafer chamber.




The post-CMP cleaning system preferably includes a temperature control system for heating the wafer process chamber.




The post-CMP cleaning system preferably includes a chemical introduction system for adding precise amounts of the chemical into the supercritical carbon dioxide process stream.




The post-CMP cleaning process of the present invention includes the following steps. The wafer is placed in the wafer process chamber. The post-CMP cleaning system is preferably purged with inert gas or the carbon dioxide. Alternatively, the post-CMP cleaning system is not purged. Next, the post-CMP cleaning system is pressurized with the carbon dioxide to achieve supercritical conditions. A desired amount of the chemical is added into the carbon dioxide, which forms chemical laden supercritical carbon dioxide. The chemical-laden supercritical carbon dioxide is contacted with the wafer. The wafer process chamber is preferably flushed using the supercritical carbon dioxide to remove contaminants. Alternatively, the wafer process chamber is flushed using the liquid carbon dioxide. The post CMP cleaning system is then depressurized to allow removal of the wafer.




The post-CMP cleaning process results in the wafer surface having a defect level that is much lower than current cleaning methods, which utilize mechanical contact of the wafer with roller or brush equipment.




The post-CMP cleaning process removes the CMP residue from semiconductors, bare silicon wafers, metallic covered wafers, and memory storage devices. It will be readily apparent to one of ordinary skill in the art that the post-CMP cleaning process removes the CMP residue from other substrates, including other semiconductor substrates, that have been polished or planarized in the CMP process.




It will be readily apparent to one skilled in the art that other various modifications may be made to the preferred embodiment without departing from the spirit and scope of the invention as defined by the appended claims.



Claims
  • 1. A method of removing a chemical mechanical polishing residue from a surface of a substrate comprising the steps of:a. placing the substrate, with the chemical mechanical polishing residue on the surface of the substrate, within a pressure chamber; b. pressurizing the pressure chamber; c. introducing supercritical carbon dioxide and a solvent into the pressure chamber, wherein the solvent is selected from the group consisting of alcohols, carbonates, glycols, ozone, fluorides, hydroxides, acids, and a mixture thereof; d. agitating the supercritical carbon dioxide and the solvent within the pressure chamber until the chemical mechanical polishing residue is removed from the semiconductor substrate; and e. flushing the pressure chamber.
  • 2. A method of removing a chemical mechanical polishing residue from a surface of a substrate comprising the steps of:a. placing the substrate, with the chemical mechanical polishing residue on the surface of the substrate, within a pressure chamber; b. pressurizing the pressure chamber; c. introducing supercritical carbon dioxide and a solvent into the pressure chamber, wherein the solvent is selected from the group consisting of isopropyl alcohol, propylene carbonate, ethylene glycol, ozone, hydrogen fluoride, ammonium hydroxide, citric acid, and a mixture thereof; d. agitating the supercritical carbon dioxide and the solvent within the pressure chamber until the chemical mechanical polishing residue is removed from the semiconductor substrate; and e. flushing the pressure chamber.
  • 3. A method of removing a chemical mechanical polishing residue from a surface of a substrate comprising the steps of:a. placing the substrate, with the chemical mechanical polishing residue on the surface of the substrate, within a pressure chamber; b. pressurizing the pressure chamber; c. introducing supercritical carbon dioxide and a solvent into the pressure chamber, wherein a volume ratio of the solvent to the supercritical carbon dioxide is within the range and including 0.001 and 15.0 percent; d. agitating the supercritical carbon dioxide and the solvent within the pressure chamber until the chemical mechanical polishing residue is removed from the semiconductor substrate; and e. flushing the pressure chamber.
RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 09/796,300, filed on Feb. 27, 2001, now U.S. Pat. No. 6,331,487, which is a continuation of U.S. patent application Ser. No. 09/407,628, filed on Sep. 28, 1999, now U.S. Pat. No. 6,277,753, which claims priority from U.S. Provisional Application No. 60/101,988, filed on Sep. 28, 1998, all of which are incorporated by reference.

US Referenced Citations (144)
Number Name Date Kind
2617719 Stewart Nov 1952 A
3890176 Bolon Jun 1975 A
3900551 Bardoncelli et al. Aug 1975 A
4029517 Rand Jun 1977 A
4091643 Zucchini May 1978 A
4219333 Harris Aug 1980 A
4341592 Shortes et al. Jul 1982 A
4474199 Blaudszun Oct 1984 A
4475993 Blander et al. Oct 1984 A
4592306 Gallego Jun 1986 A
4601181 Privat Jul 1986 A
4670126 Messer et al. Jun 1987 A
4693777 Hazano et al. Sep 1987 A
4749440 Blackwood et al. Jun 1988 A
4788043 Kagiyama et al. Nov 1988 A
4825808 Takahashi et al. May 1989 A
4838476 Rahn Jun 1989 A
4865061 Fowler et al. Sep 1989 A
4877530 Moses Oct 1989 A
4879004 Oesch et al. Nov 1989 A
4917556 Stark et al. Apr 1990 A
4923828 Gluck et al. May 1990 A
4924892 Kiba et al. May 1990 A
4933404 Beckman et al. Jun 1990 A
4944837 Nishikawa et al. Jul 1990 A
4951601 Maydan et al. Aug 1990 A
4960140 Ishijima et al. Oct 1990 A
4983223 Gessner Jan 1991 A
5011542 Weil Apr 1991 A
5013366 Jackson et al. May 1991 A
5068040 Jackson Nov 1991 A
5105556 Kurokawa et al. Apr 1992 A
5143103 Basso et al. Sep 1992 A
5158704 Fulton et al. Oct 1992 A
5174917 Monzyk Dec 1992 A
5185058 Cathey, Jr. Feb 1993 A
5185296 Morita et al. Feb 1993 A
5186718 Tepman et al. Feb 1993 A
5193560 Tanaka et al. Mar 1993 A
5201960 Starov Apr 1993 A
5213619 Jackson et al. May 1993 A
5215592 Jackson Jun 1993 A
5225173 Wai Jul 1993 A
5236602 Jackson Aug 1993 A
5237824 Pawliszyn Aug 1993 A
5238671 Matson et al. Aug 1993 A
5250078 Saus et al. Oct 1993 A
5261965 Moslehi Nov 1993 A
5266205 Fulton et al. Nov 1993 A
5267455 Dewees et al. Dec 1993 A
5269815 Schlenker et al. Dec 1993 A
5274129 Natale et al. Dec 1993 A
5288333 Tanaka et al. Feb 1994 A
5290361 Hayashida et al. Mar 1994 A
5294261 McDermott et al. Mar 1994 A
5298032 Schlenker et al. Mar 1994 A
5304515 Morita et al. Apr 1994 A
5306350 Hoy et al. Apr 1994 A
5312882 DeSimone et al. May 1994 A
5313965 Palen May 1994 A
5316591 Chao et al. May 1994 A
5334332 Lee Aug 1994 A
5334493 Fujita et al. Aug 1994 A
5337446 Smith et al. Aug 1994 A
5339844 Stanford, Jr. et al. Aug 1994 A
5352327 Witowski Oct 1994 A
5355901 Mielnik et al. Oct 1994 A
5356538 Wai et al. Oct 1994 A
5364497 Chau et al. Nov 1994 A
5368171 Jackson Nov 1994 A
5370740 Chao et al. Dec 1994 A
5370742 Mitchell et al. Dec 1994 A
5377705 Smith, Jr. et al. Jan 1995 A
5401322 Marshall Mar 1995 A
5403621 Jackson et al. Apr 1995 A
5403665 Alley et al. Apr 1995 A
5412958 Iliff et al. May 1995 A
5417768 Smith, Jr. et al. May 1995 A
5456759 Stanford, Jr. et al. Oct 1995 A
5470393 Fukawawa Nov 1995 A
5474812 Truckenmuller et al. Dec 1995 A
5482564 Douglas et al. Jan 1996 A
5486212 Mitchell et al. Jan 1996 A
5494526 Paranjpe Feb 1996 A
5500081 Bergman Mar 1996 A
5501761 Evans et al. Mar 1996 A
5505219 Lansberry et al. Apr 1996 A
5509431 Smith, Jr. et al. Apr 1996 A
5514220 Wetmore et al. May 1996 A
5522938 O'Brien Jun 1996 A
5526834 Mielnik et al. Jun 1996 A
5533538 Marshall Jul 1996 A
5547774 Gimzewski et al. Aug 1996 A
5550211 DeCrosta et al. Aug 1996 A
5580846 Hayashida et al. Dec 1996 A
5589082 Lin et al. Dec 1996 A
5589105 DeSimone et al. Dec 1996 A
5629918 Ho et al. May 1997 A
5632847 Ohno et al. May 1997 A
5635463 Muraoka Jun 1997 A
5637151 Schulz Jun 1997 A
5641887 Beckman et al. Jun 1997 A
5656097 Olesen et al. Aug 1997 A
5665527 Allen et al. Sep 1997 A
5669251 Townsend et al. Sep 1997 A
5676705 Jureller et al. Oct 1997 A
5679169 Gonzales et al. Oct 1997 A
5679171 Saga et al. Oct 1997 A
5683473 Jureller et al. Nov 1997 A
5683977 Jureller et al. Nov 1997 A
5688879 DeSimone Nov 1997 A
5700379 Biebl Dec 1997 A
5726211 Hedrick et al. Mar 1998 A
5730874 Wai et al. Mar 1998 A
5739223 DeSimone Apr 1998 A
5783082 DeSimone et al. Jul 1998 A
5797719 James et al. Aug 1998 A
5798438 Sawan et al. Aug 1998 A
5804607 Hedrick et al. Sep 1998 A
5866005 DeSimone et al. Feb 1999 A
5868856 Douglas et al. Feb 1999 A
5868862 Douglas et al. Feb 1999 A
5872257 Beckman et al. Feb 1999 A
5873948 Kim Feb 1999 A
5881577 Sauer et al. Mar 1999 A
5888050 Fitzgerald et al. Mar 1999 A
5900354 Batchelder May 1999 A
5908510 McCullough et al. Jun 1999 A
5932100 Yager et al. Aug 1999 A
5934856 Asakawa et al. Aug 1999 A
5944996 DeSimone et al. Aug 1999 A
5965025 Wai et al. Oct 1999 A
5976264 McCullough et al. Nov 1999 A
5980648 Adler Nov 1999 A
6017820 Ting et al. Jan 2000 A
6024801 Wallace et al. Feb 2000 A
6077321 Adachi et al. Jun 2000 A
6114044 Houston et al. Sep 2000 A
6149828 Vaartstra Nov 2000 A
6200943 Romack et al. Mar 2001 B1
6224774 DeSimone et al. May 2001 B1
6228826 DeYoung et al. May 2001 B1
6242165 Vaartstra Jun 2001 B1
6331487 Koch Dec 2001 B2
Foreign Referenced Citations (51)
Number Date Country
39 04 514 Aug 1990 DE
40 04 111 Aug 1990 DE
39 06 724 Sep 1990 DE
39 06 735 Sep 1990 DE
39 06 737 Sep 1990 DE
44 29 470 Mar 1995 DE
43 44 021 Jun 1995 DE
198 60 084 Jul 2000 DE
0 244 951 Nov 1987 EP
0 272 141 Jun 1988 EP
0 283 740 Sep 1988 EP
0 302 345 Feb 1989 EP
0 370 233 May 1990 EP
0 391 035 Oct 1990 EP
0 518 653 Dec 1992 EP
0 536 752 Apr 1993 EP
0 572 913 Dec 1993 EP
0 587 168 Mar 1994 EP
0 620 270 Oct 1994 EP
0 679 753 Nov 1995 EP
0 711 864 May 1996 EP
0 726 099 Aug 1996 EP
0 822 583 Feb 1998 EP
0 829 312 Mar 1998 EP
0 836 895 Apr 1998 EP
2 193 482 Feb 1988 GB
56-142629 Nov 1981 JP
60-192333 Sep 1985 JP
60-238479 Nov 1985 JP
60-246635 Dec 1985 JP
61-231166 Oct 1986 JP
62-125619 Jun 1987 JP
63-303059 Dec 1988 JP
1045131 Feb 1989 JP
2-148841 Jun 1990 JP
2-209729 Aug 1990 JP
2-304941 Dec 1990 JP
7142333 Jun 1995 JP
727711 Feb 1996 JP
8222508 Aug 1996 JP
10-144757 May 1998 JP
WO 8707309 Dec 1987 WO
WO 9006189 Jun 1990 WO
WO 9013675 Nov 1990 WO
WO 9112629 Aug 1991 WO
WO 9314255 Jul 1993 WO
WO 9314259 Jul 1993 WO
WO 9320116 Oct 1993 WO
WO 9627704 Sep 1996 WO
WO 99186603 Apr 1999 WO
WO 9949998 Oct 1999 WO
Non-Patent Literature Citations (54)
Entry
J. Rubin et al. “A Comparison of Chilled DI Water/Ozone and C02-Based Supercritical Fluids as Replacements for Photoresist-Stripping Solvents” 1998, pp. 308-314, IEEE/CPMT Int'l Electronics Manufacturing Technology Symposium.
“Los Almos National Laboratory,” Solid State Technology, pp. S10 & S14, Oct. 1998.
“Supercritical Carbon Dioxide Resist Remover, SCORR, the Path to Least Photoresistance,” Los Almos National Laboratory, 1998.
Guan, Z. et al., “Fluorocarbon-Based Heterophase Polymeric Materials. 1. Block Copolymer Surfactants for Carbon Dioxide Applications,” Macromolecules, vol. 27, 1994, pp. 5527-5532.
International Journal of Environmentally Conscious Design & Manufacturing, vol. 2, No. 1, 1993, p. 83.
Matson and Smith “Supercritical Fluids”, Journal of the American Ceramic Society, vol. 72, No. 6, pp. 872-874.
Ziger, D.H. et al., “Compressed Fluid Technology: Application to RIE Developed Resists,” AIChE Journal, vol. 33, No. 10, Oct. 1987, pp. 1585-1591.
Kirk-Othmer, “Alcohol Fuels to Toxicology,” Encycylopedia of Chemical Terminology, 3rd ed., Supplement Volume, 1984, pp. 872-893.
“Cleaning with Supercritical CO2,” NASA Tech Briefs, MFS-29611, Marshall Space Flight Center, Alabama, Mar. 1979.
Basta, N., “Supercritical Fluids: Still Seeking Acceptance,” Chemical Engineering, vol. 92, No. 3, Feb. 24, 1985, pp. 1-4.
Takahashi, D., “Los Alomos Lab Finds Way to Cut Chip Toxic Waste,” Wall Street Journal, Jun. 22, 1998.
“Supercritical CO2 Process Offers Less Mess from Semiconductor Plants”, Chemical Engineering Magazine, pp. 27 & 29, Jul. 1998.
Sun, Y.P. et al., “Preparation of Polymer-Protected Semiconductor Nanoparticles Through the Rapid Epansion of Supercritical Fluid Solution,” Chemical Physics Letters, pp. 585-588, May 22, 1998.
Jackson, K. et al., “Surfactants and Micromulsions in Supercritical Fluids,” Supercritical Fluid Cleaning. Noyes Publications, Westwood, NJ, pp. 87-120, Spring 1998.
Kryszewski, M., “Production of Metal and Semiconductor Nanoparticles in Polymer Systems,” Polymery, pp. 65-73, Feb. 1998.
Bakker, G.L. et al., “Surface Cleaning and Carbonaceous Film Removal Using High Pressure, High Temperature Water, and Water/C02 Mixtures,” J. Electrochem. Soc. vol. 145, No. 1, pp. 284-291, Jan. 1998.
Ober, C.K. et al., “Imaging Polymers with Supercritical Carbon Dioxide,” Advanced Materials, vol. 9, No. 13, 1039-1043, Nov. 1997.
Russick, E.M. et al., “Supercritical Carbon Dioxide Extraction of Solvent from Micromachined Structures.” Supercritical Fluids Extraction and Pollution Prevention, ACS Symposium Series, vol. 670, pp. 255-269, Oct. 21, 1997.
Dahmen, N. et al., “Supercritical Fluid Extraction of Grinding and Metal Cutting Waste Contaminated with Oils,” Supercritical Fluids—Extraction and Pollution Prevention, ACS Symposium Series, vol. 670, pp. 270-279, Oct. 21, 1997.
Wai, C.M., “Supercritical Fluid Extraction: Metals as Complexes,” Journal of Chromatogrpahy A, vol. 785, pp. 369-383, Oct. 17, 1997.
Xu, C. et al., “Submicron-Sized Spherical Yttrium Oxide Based Phosphores Prepared by Supercritical CO2-Assisted aerosolization and pyrolysis,” Appl. Phys. Lett., vol. 71, No. 12, Sep. 22, 1997, pp. 1643-1645.
Tomioka Y, et al., “Decomposition of Tetramethylammonium (TMA) in a Positive Photoresist Developer by Supercritical Water,” Abstracts of Papers 214th ACS Natl Meeting, American Chemical Society, Abstract No. 108, Sep. 7, 1997.
Klein, H. et al., “Cyclic Organic Carbonates Serve as Solvents and Reactive Diluents,” Coatings World pp. 38-40, May 1997.
Bühler, J. et al., Liner Array of Complementary Metal Oxide Semiconductor Double-Pass Metal Micromirrors, Opt. Eng., vol. 36, No. 5, pp. 1391-1398, May 1997.
Jo, M.H. et al., Evaluating of SIO2 Aerogel Thin Film with Ultra Low Dielectric Constant as an Intermetal Dielectric, Microelectronic Engineering, vol. 33, pp. 343-348, Jan. 1997.
McClain, J.B. et al., “Design of Nonionic Surfactants for Supercritical Carbon Dioxide,” Science, vol. 27 4, Dec. 20, 1996, pp. 2049-2052.
Znaidi, L. et al., “Batch and Semi-Continous Synthesis of Magnesium Oxide Powders from Hydrolysis and Supercritical Treatment of Mg(OCH3)2,” Materials Research Bulletin, vol. 31, No. 12, pp. 1527-1535, Dec. 1996.
Tadros, M.E., “Synthesis of Titanium Dioxide Particles in Supercritical CO2,” J. Supercritical Fluids, vol. 9, pp. 172-176, Sep. 1996.
Courtecuisse, V.G. et al., “Kinetics of the Titanium Isopropoxide Decomposition in Supercritical Isopropyl Alcohol,” Ind. Eng. Chem. Res., vol. 35, No. 8, pp. 2539-2545, Aug. 1996.
Gabor, A, et al., “Block and Random Copolymer resists Designed for 193 nm Lithography and Enviromentally Friendly Supercritical CO2 Development,” Dept. Mat. Sci & Eng. Cornell Univ. SPIE, vol. 2724, pp. 410-417, Jun. 1995.
Schimek, G. L. et al., “Supercritical Ammonium Synthesis and Charaterization of Four New Alkali Metal Silver Antimony Sulfides . . . ,” J. Solid State Chemistry, vol. 123 pp. 277-284, May 1996.
Gallagher-Wetmore, P. et al., “Supercritical Fluid Processing: Opportunities for New Resist Materials and Processes,” IBM Research Division, SPIE, vol. 2725, pp. 289-299, Apr. 1996.
Papathomas, K.J. et al., “Debonding of Photoresists by Organic Solvents,” J. Applied Polymer Science, vol. 59, pp. 2029-2037, Mar. 28, 1996.
Watkins, J.J. et al., “Polymer/metal Nanocomposite Synthesis in Supercritical CO2,” Chemistry of Materials, vol. 7, No. 11, Nov. 1995., pp. 1991-1994.
Gloyna, E.F. et al., “Supercritical Water Oxidation Research and Development Update,” Environment Progess, vol. 14, No. 3. Pp. 182-192 Aug. 1995.
Gallagher-Wetmore, P. et al., “Supercritical Fluid Processing: A New Dry Technique for Photoresist Developing,” IBM Research Division, SPIE vol. 2438, pp. 694-708, Jun. 1995.
Gabor, A. H. et al., “Silicon-Containing Block Copolymer Resist Materials,” Microelectronics Technology—Polymers for Advanced Imaging and Packaging, ACS Symposium Series, vol. 614, pp. 281-298, Apr. 1995.
Tsiartas, P.C. et al., “Effect of Molecular weight Distribution on the Dissolution Properties of Novolac Blends,” SPIE, vol. 2438, pp. 261-271, 1995.
Allen, R.D. et al., “Performance Properties of Near-monodisperse Novolak Resins,” SPIE, vol. 2438, pp. 250-260, 1995.
Wood, P.T. et al., “Synthesis of New Channeled Structures in Supercritical Amines . . . ,” Inorg. Chem., vol. 33, pp. 1556-1558, 1994.
Jerome, J.E. et al., “Synthesis of New Low-Dimensional Quaternary Compounds . . . ,” Inorg. Chem, vol. 33, pp. 1733-1734, 1994.
McHardy, J. et al., “Progress in Supercritical CO2 Cleaning,” SAMPE Journ., vol. 29, No. 5, pp. 20-27, Sep. 1993.
Purtell, R, et al., “Precision Parts Cleaning using Supercritical Fluids,” J. Vac, Sci, Technol. A. vol. 11, No. 4, Jul. 1993, pp. 1696-1701.
Bok, E, et al., “Supercritical Fluids for Single Wafer Cleaning,” Solids State Technology, pp. 117-120, Jun. 1992.
Adschiri, T. et al., “Rapid and Continuous Hydrothermal Crystallization of Metal Oxide Particles in Supercritical Water,” J. Am. Ceram. Soc., vol. 75, No. 4, pp. 1019-1022, 1992.
Hansen, B.N. et al., “Supercritical Fluid Transport—Chemical Deposition of Films,” Chem. Mater., vol. 4, No. 4, pp. 749-752, 1992.
Page, S.H. et al., “Predictability and Effect of Phase Behavior of CO2/Propylene Carbonate in Supercritical Fluid Chromatography,” J. Microl. Sep, vol. 3, No. 4, pp. 355-369.
Brokamp, T. et al., “Synthese und Kristallstruktur Eines Gemischtvalenten Lithium-Tanalnitrids Li2Ta3Ns,” J. Alloys and Compounds, vol. 176, pp. 47-60, 1991.
Hybertson, B.M. et al., “Deposition of Palladium Films by a Novel Supercritical Fluid Transport Chemical Deposition Process,” Mat. Res. Bull., vol. 26, pp. 1127-1133, 1991.
Ziger, D. H. et al., “Compressed Fluid Technology: Application to RIE-Developed Resists,” AiChE Jour., vol. 33, No. 10, pp. 1585-1591, Oct. 1987.
Matson, D.W. et al., “Rapid Expansion of Supercritical Fluid Solutions: Solute Formation of Powders, Thin Films, and Fibers,” Ind. Eng. Chem. Res., vol. 26, No. 11, pp. 2298-2306, 1987.
Tolley, W.K. et al., “Stripping Organics from Metal and Mineral Surfaces using Supercritical Fluids,” Separation Science and Technology, vol. 2+3, pp. 1087-1099, 1987.
“Final Report on the Safety Assessment of Propylene Carbonate,” J. American College of Toxicology, vol. 6, No. 2, pp. 23-51, 1987.
Hideaki Itakura et al., “Multi-Chamber Dry Etching System”, Solid State Technology, Apr. 1982, pp. 209-214.
Provisional Applications (1)
Number Date Country
60/101988 Sep 1998 US
Continuations (2)
Number Date Country
Parent 09/796300 Feb 2001 US
Child 10/042486 US
Parent 09/407628 Sep 1999 US
Child 09/796300 US