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`Samsung Electronics Co., Ltd. v. Demaray LLC
`Samsung Electronic's Exhibit 1011
`Exhibit 1011, Page 1
`
`

`

`
`5,942,089
`Page 2
`
`
`
`
`OTHER PUBLICATIONS
`
`
`
`
`
`
`
`
`W. D. Sproul, P. J. Rudnik and M. E. Graham, The Effect of
`
`
`
`
`
`
`
`N.Partial Pressure, Deposition Rate and Substrate Bias
`
`
`
`
`
`
`
`Potential on the Hardness and Texture of Reactively Sput-
`
`
`
`
`
`
`
`tered TiN Coatings, Surface and Coatings Technology,
`
`
`
`39/40 (1989) 355-363.
`
`
`
`
`
`
`
`
`X. Chu, M.S. Wong, W. D. Sproul, S. L. Rohde and S. A.
`
`
`
`
`
`
`Barnett, Deposition and Properties of Polycrystalline TiN/
`
`
`
`
`
`
`
`NbN Superlattice Coatings, J. Vac Sci. Technol. A 10(A4),
`
`
`Jul./Aug. 1992.
`
`
`
`
`
`
`William D. Sproul, Control ofA Reactive Sputtering Process
`
`
`
`
`
`
`
`
`For Large Systems, Presented at
`the Society of Vacuum
`
`
`
`
`
`
`
`Coaters 36th Annual Technical Conference, Dallas, Texas,
`
`
`
`Apr. 30, 1993.
`
`
`
`
`
`
`
`
`J. Affinito and R. R. Parsons, Mechanisms of Voltage
`
`
`
`
`
`Controlled, Reactive, Planar Magnetron Sputtering of Al in
`
`
`
`
`
`
`
`At/N, and AR/O, Atmospheres, J. Vac. Sci. Technol. A 2(3),
`
`
`Jul-Sep. 1984.
`
`
`
`
`
`
`
`
`
`S. Schiller, K. Goedicke, J. Reschke, V. Kirchhoff, S.
`
`
`
`
`
`
`
`Schneider and F. Milde, Pulsed Magnetron Sputter Technol-
`
`
`
`
`
`
`
`ogy, Surface and Coatings Technology, 61 (1993) 331-337.
`
`
`
`
`
`
`
`
`P. Frach, U. Heisig, Chr. Gottfried and H. Walde, Aspects
`
`
`
`
`
`
`
`and Results of Long—Term Stable Deposition of Al,O, With
`
`
`
`
`
`
`
`High Rate Pulsed Reactive Magnetron Sputtering, Surface
`
`
`
`
`
`and Coatings Technology, 59 (1993) 177-182.
`
`
`
`
`
`
`W. D. Sproul, M. E. Graham, M. S. Wong, S. Lopez, and D.
`
`
`
`
`
`
`
`Li, Reactive Direct Current Magnetron Sputtering of Alu-
`
`
`
`
`
`
`
`minum Oxide Coatings. J. Vac. Sci. Technol. A 13(3),
`
`
`May/Jun. 1995.
`
`
`
`
`
`
`
`William D. Sproul, Michael E. Graham, Ming—Show and
`
`
`
`
`
`
`
`Paul J. Rudnik, Reactive DC Magnetron Sputtering of the
`
`
`
`
`
`
`
`
`Oxides of Ti, Zr, and Hf, Presented at
`the International
`
`
`
`
`
`
`
`Conference on Metallurgical Coatings and Thin Films,
`
`
`
`
`
`
`
`
`Town and Country Hotel, San Diego, California, Apr. 24-28,
`
`
`
`
`
`
`
`
`1994 and Submitted for publication in Surface and Coatings
`
`Technology.
`
`Ex. 1011, Page 2
`
`Ex. 1011, Page 2
`
`

`

`U.S. Patent
`
`Aug.24, 1999
`
`Sheet 1 of 5
`
`5,942,089
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`
`
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`
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`
`
`

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`U.S. Patent
`
`Aug. 24, 1999
`
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`
`

`

`U.S. Patent
`
`Aug.24, 1999
`
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`
`Ex. 1011, Page 5
`
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`
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`Ex. 1011, Page 6
`
`Ex. 1011, Page 6
`
`

`

`U.S. Patent
`
`Aug. 24, 1999
`
`Sheet 5 of 5
`
`5,942,089
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`Ex. 1011, Page 7
`
`

`

`
`1
`METHOD FOR SPUTTERING COMPOUNDS
`
`
`
`ON A SUBSTRATE
`
`
`BACKGROUND OF THE INVENTION
`
`
`
`
`2
`
`
`
`
`
`
`
`
`Sputtering techniques for the application of pure metals
`
`
`
`
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`
`
`
`are fairly well refined and effective. Additionally, sputtering
`
`
`
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`
`
`techniques for conductive or non-insulating compounds
`
`
`
`
`
`
`
`have been somewhat successful utilizing the techniques
`
`
`
`
`
`
`described in the aforesaid publications. However, certain
`
`
`
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`
`
`
`
`Briefly,
`the present invention relates to a method and
`
`
`
`
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`
`
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`
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`materials, which provide an insulating, hard coating upon a
`apparatus for sputtering of a thin film of a compound onto
`
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`
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`
`
`
`substrate are difficult
`to apply as a film or may not be
`
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`
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`a substrate workpiece by means of cathodic, magnetron
`
`
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`
`
`
`
`
`efficiently applied using such sputtering techniques. Alumi-
`sputtering.
`
`
`
`
`
`
`
`
`
`num oxide, for example, has heretofore been applied by
`
`
`
`
`
`
`Application of metals and metallic compounds by use of
`
`
`
`
`
`
`sputtering techniques to a substrate at only a small fraction
`
`
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`
`
`
`
`
`a reactive deposition process is knownandisthe subject, for
`
`
`
`
`
`
`
`
`of the rate and efficiency of the application associated with
`
`
`
`
`
`
`
`
`example, of U.S. Pat. No. 4,428,811, “Rapid Rate Reactive
`
`
`
`
`
`
`
`
`
`the pure aluminum metal. Thus, low deposition rates of
`
`
`
`
`
`
`
`
`Sputtering Of A Group IVB Metal” issued Jan. 31, 1984,
`
`
`
`
`
`
`
`insulating or non-conductive metal compounds have con-
`
`
`
`
`
`
`
`incorporated herewith by reference. U.S. Pat. No. 4,428,811
`
`
`
`
`
`
`
`tinued to pose a challenge. Publications that reflect research
`
`
`
`
`
`
`
`
`discloses a method and apparatus for rapid rate deposition of
`
`
`
`
`
`
`
`
`regarding the sputtering of such compounds include the
`
`
`
`
`
`
`
`metallic compoundssuchas titanium nitride onto a substrate
`
`
`
`
`
`
`following, which are incorporated herewith by reference:
`
`
`
`
`
`
`
`
`in a vacuum chamber. In the process, the chamberis filled
`
`
`
`
`
`
`
`9. “Aspects and Results of Long-Term Stable Deposition
`
`
`
`
`
`
`
`
`
`
`with inert gas that is ionized and bombards the metal target
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`of AlL,O, with High Rate Pulsed Reactive Magnetron
`within the chamber to initiate the sputtering process. A
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Sputtering,” published in Surface and Coatings Technology,
`substrate is positioned within the chamber for coating, and
`20
`1993;
`
`
`
`
`
`
`
`
`
`
`a second reactive gas is fed into the chamber at a measured
`rate to combine at the substrate with the atomized metal
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`10. “Reactive Direct Current Magnetron Sputtering of
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`from the target to form the coating. Control systems for such
`Aluminum Oxide Coatings,” J. Vac. Sci. Technol. A 13(3),
`
`
`
`
`
`
`
`
`
`
`
`sputtering operations are also disclosed in the aforesaid
`May/June 1995; and
`
`patent.
`
`
`
`
`
`
`11. “Reactive DC Magnetron Sputtering of the Oxides of
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Overthe years, the technology associated with sputtering
`Ti, Zr, and Hf,” presented at the International Conference on
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`processes has been improved so that additional compounds
`Metallurgical Coatings and Thin Films, Town and Country
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`and materials can be applied to a substrate by. A series of
`Hotel, San Diego, Calif., Apr. 24-28, 1995, and accepted for
`
`
`
`
`
`
`
`
`
`
`
`
`papers by the co-inventorreflect research in this area includ-
`publication in Surface and Coatings Technology.
`
`
`
`ing the following:
`
`
`
`
`
`
`
`In sum,there has remained a need to provide an improved
`
`
`
`
`
`
`
`
`
`
`
`
`
`1. “High Rate Reactive Sputtering Process Control,”
`method and apparatus for the deposition of metallic, insu-
`
`
`
`
`
`
`
`
`
`
`
`published in Surface and Coatings Technology, 1987;
`lating compounds such as aluminum oxide, on a substrate
`
`
`
`
`
`
`
`
`
`
`
`
`using sputtering techniques.
`2. “The Effect of Target Power on the Nitrogen Partial
`
`
`
`
`
`
`
`Pressure Level and Hardness of Reactively Sputtered Tita-
`SUMMARYOF THE INVENTION
`
`
`
`
`
`
`
`
`
`
`nium Nitride Coatings,” published in Thin Solid Films,
`
`
`
`
`
`
`
`1989;
`
`In a principal aspect, the present invention comprises a
`
`
`
`
`
`
`
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`
`
`
`
`method for deposition of various compounds, especially
`3. “Advancesin Partial-Pressure Control Applied to Reac-
`
`
`
`
`
`
`
`
`
`
`
`
`insulating, metallic compounds such as aluminum oxide, on
`tive Sputtering,” published in Surface and Coatings
`
`
`
`
`
`
`
`
`
`a substrate as a thin film by sputtering techniques utilizing
`Technology, 1989;
`
`
`
`
`
`
`
`
`a pulsed, constant power, direct current electric power
`
`
`
`
`
`
`
`
`4. “The Effect of N., Partial Pressure, Deposition Rate and
`Substrate Bias Potential on the Hardness and Texture of
`
`
`
`
`
`
`
`supply to cause ionization of an inert gas that bombards a
`
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`target thereby releasing the atomsofthe target into a vacuum
`Reactively Sputtered TIN Coatings,” published in Surface
`
`
`
`
`
`
`
`
`
`
`
`
`
`chamber and further controlling the rate of admission and
`and Coatings Technology, 1989;
`
`
`
`
`
`
`
`
`
`thus the reaction of a second, reactive gas to the chamber
`
`
`
`
`
`
`5. “Deposition and Properties of Polycrystalline TiN/NbN
`45
`
`
`
`
`
`
`
`with a combination of control signals. Specifically, the rate
`
`
`
`
`
`
`
`Superlattice Coatings,” published in J. Vac. Sci. Technol. A
`
`
`
`
`
`
`
`
`of admissionis controlled byafirst signal derived from the
`
`
`
`
`10/4, July/August 1992; and
`
`
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`
`
`
`
`measured voltage of the target which is maintained at a
`
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`
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`
`
`6. “Control of a Reactive Sputtering Process for Large
`
`
`
`
`
`
`
`
`constant power setting. The rate of admission is further
`
`
`
`
`
`
`
`
`Systems,” a paper presented at
`the Society of Vacuum
`
`
`
`
`
`
`
`controlled by a second signal derived from the measured
`
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`
`
`
`
`Coaters, 36th Annual Technical Conference, Dallas, Tex.,
`
`
`
`
`
`
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`
`
`partial pressure of the reactive gas. The partial pressure of
`
`
`
`Apr. 30, 1993.
`
`
`
`
`
`
`
`
`the reactive gas is sensed by means such as an optical gas
`
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`The text of these publications is incorporated herewith by
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`controller or mass spectrometer, as well as the target voltage,
`reference.
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`is sensed to provide control signals representative of the
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`The energy source whicheffects the ionization of the inert
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`desired composition and physical characteristics of the thin
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`gas in a sputtering system has evolved overtime so that now
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`film. The desired composition and physical characteristics
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`pulsed, direct current electrical power is known to be a
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`are derived empirically for given target materials, reactive
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`preferred energy source to the target material. Publications
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`gases and powersettings. To further enhance the thin film
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`relating to this technique and technology include the fol-
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`deposition process, the reactive gas at or near the substrate
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`lowing:
`is subjected to local energy input, for example, by applying
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`7. “Mechanisms of Voltage Controlled, Reactive, Planar
`pulsed direct current to the substrate. By the method, it is
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`Magnetron Sputtering of Al
`in Ar/N, and Ar/O,
`possible to carefully control the amountof reactive gas in the
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`Atmospheres,” published in J. Vac. Sci. Technol. A 2(3),
`system and thereby increase the rate of deposition of the
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`July-September 1984; and
`compound multiple times the rate of deposition using prior
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`8. “Pulsed Magnetron Sputter Technology,” published in
`sputtering techniques.
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`Surface and Coatings Technology, 1993.
`it
`is an object of the invention to provide an
`Thus,
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`These publications are incorporated herewith by refer-
`improved method and apparatus for deposition of com-
`ence.
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`pounds on a substrate by sputtering techniques.
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`5,942,089
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`Ex. 1011, Page 8
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`Ex. 1011, Page 8
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`3
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`It
`is a further object of the invention to provide an
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`improved method for deposition by sputtering of com-
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`pounds including oxides, nitrides,
`fluorides, sulfides,
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`chlorides, borides and mixtures thereof.
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`Another object of the invention is to provide an improved
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`and highly efficient method and apparatus for deposition of
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`insulating, metal compounds on a substrate utilizing
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`improved control techniques.
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`Another object of the invention is to provide an improved
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`method for deposition of thin films of insulating, metal
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`compounds on a substrate at rates which are multiples of the
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`rates of prior art sputtering techniques.
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`Another object of the invention is to provide an improved
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`method for deposition of metal and semi-conductor com-
`15
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`poundsas thin films using sputtering techniques.
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`A further object of the invention is to provide a method for
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`effecting efficient deposition of compounds by sputtering
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`techniques utilizing a constant power, pulsed direct current
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`powersupply for the target material and control signals for
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`controlling the admission of reactive gas wherein one signal
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`is reflective of the voltage of the target power source and
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`another signal is reflective of the partial pressure of the
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`reactive gas used in the practice of the process.
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`These and other objects, advantages and features of the
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`invention will be set forth in the detailed description as
`follows.
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`BRIEF DESCRIPTION OF THE DRAWING
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`In the detailed description which follows, reference will
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`be made to the drawing comprised of the following figures:
`FIG. 1 is a schematic of a vacuum chamber and the
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`control circuitry associated therewith for the practice of the
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`method of the invention;
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`FIG. 2 is a graph depicting a symmetric, bipolar pulsed,
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`direct current power supply wave;
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`FIG. 3 is a graph depicting an asymmetric, bipolar pulsed
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`direct current power supply wave;
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`FIG. 4 is a graph depicting the target voltage/oxygen
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`partial pressure hysteresis curve for the reactive sputtering
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`of aluminum in an argon/oxygen atmosphere; and
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`FIG. 5 is a graph depicting the oxygen reactive gas
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`flow/oxygenpartial pressure hysteresis curve for the reactive
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`sputtering of aluminum in an argon/oxygen atmosphere;
`DESCRIPTION OF THE PREFERRED
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`EMBODIMENT
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`Overview And General Description
`The method of the invention as well as the associated
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`apparatus are designed to optimize the conditions for reac-
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`tion between atomized target material and reactive gas to
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`form and deposit a thin film compound in a sputtering
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`system. Thus referring to FIG. 1 ,
`there is depicted the
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`componentparts of a sputtering system used to practice the
`invention.
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`Avacuum chamber10 is evacuated by a pump 12 after a
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`substrate material 14, e.g. quartz or a piece of steel
`is
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`mounted on a holder 16 within the chamber 10. A target
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`material 18, e.g. Aluminum or some other metal or semi-
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`conductor material, is also mounted within the chamber10.
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`The target 18 serves as a cathode in the process and the
`inside walls 20 of chamber 10 serve as an anode. An inert
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`gas, e.g. Argon (An),
`is admitted to chamber 10 from a
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`source 22 via a meter 24 and valve 26 controlled by a
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`controller 28 responsive to a pressure sensor 30.
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`The target 18 is subject to a bipolar, pulsed, direct current
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`power source 32 of the type generally knownin the art. The
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`source 32 is preferably asymmetric as depicted in FIG. 3
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`with the cathode negatively biased, although a symmetric
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`source 32, as depicted in FIG. 2, may be utilized.
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`A reactive gas, such as oxygen,is provided from a source
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`34 through a flow meter 36 and control valve 38 via a
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`conduit 40 to the vicinity of the target 18 whereits proximity
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`to atoms from the target will enhance reaction therewith. The
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`reactive gas control valve 38 is responsive to a plurality of
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`sensing or feedback signals which are input to a controller
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`42 which, upon proper processing, provides a control signal
`via link 44 to valve 38.
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`The signals to the controller 42 are derived from two
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`sources, first
`the voltage of the target 18 is constantly
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`monitored. Second,the partial pressure of the reactive gas is
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`monitored. Regarding the voltage target 18, this voltage may
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`vary since the power to the target 18 is maintained at a
`constant value. For each set of conditions within the
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`chamber, therefore, for a given target and reactive gas,it is
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`possible to derive the relationship between such constant
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`power voltage and the partial pressure of the reactive gas
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`thereby identifying the optimal range of partial pressure and
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`voltage for formation of the compound comprised of the
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`target material and reactive gas. An example of this empiri-
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`cal derivation is depicted in FIG. 4 for a target material of
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`aluminum in an argon/oxygen atmospherefor increasing and
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`decreasing oxygen partial pressure wherein the target power
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`was 2 kilowatts from a 20 kHz, pulsed direct current source
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`and the total chamberpressure was 4 mTorr. Note that partial
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`pressure of about 0.03 mTorrat a target voltage of 270 to 380
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`volts is indicative of highly efficient film formation. This
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`information or information of this type is derived from an
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`experimental ortest run, and the results are programmed into
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`controller 42 thus enabling the controller 42 the capability to
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`provide almost
`instantaneous feedback control
`input
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`because voltage measurements provided to the controller 42
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`from target 18 are inherently rapid. Thus, the voltage feed-
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`back signal provides a highly sensitive, rapid response,
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`control function, when empirical or full range test run,
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`hystersis information derived from an experiment or full
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`range test run of the type reflected by FIG. 4 is programmed
`into the controller 42.
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`Simultaneous with the rapid control signal derived from
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`the voltage of target 18, a second less rapid signal is derived
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`by directly measuring the partial pressure of the reactive gas,
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`e.g. oxygen. Thus, as depicted in FIG. 1, a mass spectrom-
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`eter 46, for example, or a partial pressure controller, e.g. an
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`analyzer (OGC made by Leybold Infilon of East Syracuse,
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`N.Y.) is provided to determine the partial pressure of the
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`specific reactive gas. Note the signal derived from sensor 46
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`is species specific, e.g. oxygen; whereas the target voltage
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`signal is not. Thus,
`the target voltage signal, previously
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`described, may result, at least in part, due to phenomena
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`other than the partial, pressure of the reactive gas. For
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`example, out gassing from the substrate or chamber walls
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`may have an impact on the signal. Thus, the reactive gas
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`sensor 46 provides a signal 48 to the controller which is
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`reflective of the true partial pressure of the reactive gas
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`(oxygen) albeit a slowly developed or slowly derived signal
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`relative to the target voltage signal because of the instru-
`mentation involved.
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`In any event,
`the meaning of the signal 48 is also
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`dependent upon the empirical relationship between reactive
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`gas partial pressure and flow rate. This relationship is
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`derived simultaneously with the empirical power voltage/
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`partial pressure relationship discussed with regard to FIG. 4
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`for each specific set of conditions. FIG. 5 is a graph
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`depicting the relationship for the same conditions (in fact,
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`derived during the same empirical experimental run) as FIG.
`4.
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`Ex. 1011, Page 9
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`Ex. 1011, Page 9
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`

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`5,942,089
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`5
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`Referring to FIG. 5, for the reported conditions and
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`materials, which is the same as specified for the data of FIG.
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`4, the optimal partial pressure is in the range of about 0.02
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`mTorr, at which point the oxygen flow is in the range of 15
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`to 20 Sccm. Thus,
`the signal 48 from sensor 46 can be
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`utilized to “zero” or set the controller 42 so that the target
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`voltage signal to controller 42 is working from an appro-
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`priate base line.
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`One further input to the system is provided to enhance the
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`film deposition process. An energy source 50 provides a
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`meansfor activating the reactive gas, e.g. Oxygen,at or near
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`the substrate 14. For example, a pulsed direct current power
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`supply may be applied to the substrate 14. Other energy
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`sources include a radio frequency voltage source, lasers,
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`electron beams, a microwave source, or an inductively
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`coupled plasma source. A radio frequency source of 13.56
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`MHZ or a harmonic multiple thereof may be used. The
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`energy input at the substrate 14 has the effect of enhancing
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`the process efficiency as reflected by the data derived in
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`FIGS. 4 and 5, by way of example, so as to increase flow rate
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`and voltage at optimal conditions.
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`Also by correlating the data of the type derived in FIGS.
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`4 and 5 with various physical parameters of the film
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`compound, it becomes possible to apply films having cus-
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`tomized characteristics. For example, each of the data points
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`of FIGS. 4 and 5 are representative of compounds having
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`associated therewith a variety of measurable physical char-
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`acteristics including conductivity, modulus, hardness,
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`extinction coefficient, index of refraction,reflectivity, trans-
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`mission and constituent composition. By controlling the
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`sputtering process to such data points, as it is possible to do
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`with this process, the desired custom film may be sputter
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`applied to a substrate 14.
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`in the deposition of
`The process is especially useful
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`insulating, metal compounds such as aluminum oxide.
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`Experimental results demonstrate application rates 15 to 20
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`times better than prior techniques. For example, with the
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`reactive sputtering of stoichiometric Al,O,, the deposition
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`rate had been increased from about 5% of the metal depo-
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`sition rate to 70% or more of the metal deposition rate. Also,
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`the process is useful with many compounds including
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`oxides, nitrides, carbides, sulfides,
`fluorides, chlorides,
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`borides and mixtures thereof. Numerous metals, including
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`aluminum,titanium, hafnium, zirconium, tantalum,silicon,
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`and chromium have been successfully used as the target
`material.
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`Specific Example:
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`Following is a specific example of the practice of the
`invention:
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`Deposition of Aluminum Oxide by Means of
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`Reactive DC Sputtering
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`Aluminum oxide (stoichiometric composition but non-
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`crystalline) may be deposited using the following deposition
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`system hardware:
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`The substrate to be coated is placed in a stainless steel
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`vacuum chamber, approximately 29" o0.d. and about 30"
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`high, whichis electrically groundedto earth potential and is
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`pumped with a 6" diffusion pump and a 1500 1/s turbo-
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`molecular pump, which are both backed up with appropri-
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`ately sized mechanical pumps(in this case, Edwards EM2-
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`80’s) capable of achieving a base pressure of 1x10~° Torr.
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`The substrate may bea flat glass slide or other material of
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`choice, which is mounted on the 5"-diameter, rotatable
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`substrate table. The closest approach of the substrate to the
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`target is about 3" and it may berotated or held stationary
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`during coating.
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`6
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`Two nominally 5"x15" rectangular MRCInsettargets are
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`mounted vertically, opposing one another about 11" apart
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`unbalanced magnetron design, which enhances the plasma
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`density in the vicinity of the substrate, and at least one target
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`is aluminum with a metallic purity of at least 99.99%.
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`The cathodes (targets) are each connected to Advanced
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`Energy MDX 10 kW de power supplies through 20 kHz
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`Sparc-Le (or higher frequency) units which together provide
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`a pulsed de power and suppression of arcing on the target
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`surface during sputtering.
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`The substrate table is connected to a 3 kW rf power
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`supply, and the induced de voltage is read out through a
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`meter which is shielded from rf power by means of an
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`appropriatefilter.
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`The total gas pressure in the chamber is monitored by a
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`Baratron (capacitance manometer) for sputtering pressures
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`(1-10 mTorr), and lower pressures are monitored with a
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`Bayard-Alpert type ionization gauge. The ionization gauge
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`is also used as a reference in checking the calibration of the
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`partial pressure sensors (OGC or mass spec.), or a more
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`stable instrument such as a spinning rotor gauge can be used
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`and is preferred if available.
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`The partial pressures of all gases in the system are
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`monitored with an Inficon Quadrex 100, quadrupole mass
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`spectrometer, and two of the gases (oxygen and argon) are
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`monitored with an Inficon OGC (Optical Gas Controller).
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`The mass spectrometer is attached to a sampling system
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`whichis differentially pumped,since it requires an operating
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`pressure that is typically in the 10-° Torr range, and is
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`mounted to the top of the chamber. The OGC is attached
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`directly to the back of the chamber through a standard KF
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`flange, since it operates at sputtering pressures.
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`The gas flow controllers are MKS model 260 with modi-
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`fications that allow them to respond to pressure signals
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`instead of flow signals. In this case, the total pressure is
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`maintained constant by a feedback control involving the
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`Baratron and the MKScontroller. The target voltage on the
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`aluminum target is used as the primary indicator of oxygen
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`partial pressure during sputtering and is used as a feedback
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`signal to the MKScontroller which operates the inlet valve
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`for a quick response to any deviations in partial pressure
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`(voltage). Since the voltage is not a unique signal with
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`respect to the partial pressure of oxygen, the OGC or the
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`mass spectrometer is used to provide a feedback signal for
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`the voltage set point, which is thus tied to the actual desired
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`level of oxygen partial pressure. This OGC or mass spec-
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`trometer value is updated more slowly than the voltage. This
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`dual feedback loop provides a fast response that optimizes
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`the process control and maintains a unique relationship
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`between the control set points and the selected partial
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`pressure of oxygen.
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`In order for the process to function in the preferred
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`manner, one desires to also establish an anode surface in
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`close proximity to the plasma but shielded from deposition,
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`since the insulating film produced in the process will cause
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`the anode to become non-functional if not protected and
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`would cause the process to stop.
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`Deposition protocol:
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`The appropriate partial pressure of oxygen has been
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`previously selected from an initial determination of the
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`hysteresis curve, which relates the gas flow (see FIG. 5) and
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`the target voltage (see FIG. 4) to the set partial pressure of
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`oxygen in a fixed and determinable way for a given system
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`and given operating conditions. The partial pressure that is
`selected will be that which uses the least amountof reactive
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`Ex. 1011, Page 10
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`Ex. 1011, Page 10
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`5,942,089
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`7
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`gas and still makes a coating with the desired properties.
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`Once the partial pressure of O, has been determined that
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`corresponds to the desired properties of the oxide coating
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`(e.g., optically clear), and the target voltage for that partial
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`pressure is known, the necessary set points for the process
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`can be inserted into the controllers.
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`The following operating parameters areset:
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