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`PATENT
`Customer Number 22,852
`Attorney Docket No. 9140.0016-02
`
`IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`Commissioner for Patents
`P.O. Box 1450
`Alexandria, VA 22313-1450 ·
`
`Prior Application Art Unit: 2823
`
`Prior Application Examiner: ESTRADA, Michelle
`
`SIR: This is a request for filing a
`D Continuation O Continuation-in-Part [2J Divisional Application under 37 C.F.R. § l .53(b)
`of pending prior Application No. 10/101,863 filed March 16, 2002, ofHongmei ZHANG,
`Mukundan NARASINHAN, Ravi B. MULLAPUDI, and Richard E. DEMARAY for BIASED
`PULSE DC REACTIVE SPUTTERING OF OXIDE FILMS.
`
`1.
`
`2.
`
`3.
`
`Enclosed is a complete copy of the prior application including the oath or
`Declaration and drawings, if any, as originally filed. I hereby verify that the
`attached papers are a true copy of prior Application No. 10/101,863 as originally
`filed on March 16, 2002, which is incorporated herein by reference.
`
`A Preliminary Amendment is enclosed.
`
`The filing fee is calculated on the basis of the claims existing in the prior
`application as amended in the Preliminary Amendment filed herewith.
`
`Page 1 of 472
`
`APPLIED MATERIALS EXHIBIT 1004
`
`
`
`Page 2 of 3
`
`$300
`
`$500
`
`$200
`
`$ 300.00
`
`500.00
`
`200.00
`
`0
`
`0
`
`0
`
`0
`
`$ 1,000.00
`-
`$ 1,000.00
`
`0
`
`Basic Utility Application Filing Fee
`
`Search Fee
`
`Examination Fee
`
`Total Claims
`
`Number of Claims
`7 -
`2 -
`
`Basic
`
`Extra
`
`20
`
`3
`
`0 X $ 50
`
`0 X $200
`
`+$360
`
`Independent Claims
`LJ Presentation of Multiple Dep. Claim(s)
`
`Total Application Pages
`(specification, drawings, and printed
`sequence or computer listing)
`Subtotal
`
`Reduction by 1/2 if small entity
`
`TOTAL APPLICATION FILING FEE
`
`66
`
`If over 100 pages, add $250 for
`each additional 50 pages or
`fraction thereof.
`
`4. ~ The Commissioner is hereby authorized to charge the fee of$1,000.00 to Deposit
`Account No. 06-0916.
`
`5. ~ The Commissioner is hereby authorized to charge any fees which may be required
`including fees due under 37 C.F.R. § 1.16 and any other fees due under 37 C.F.R.
`§ 1.17, or credit any overpayment during the pendency of this application to
`Deposit Account No. 06-0916.
`
`6.
`
`7.
`
`8.
`
`[2J
`
`[2J
`
`[g].
`
`The prior application is assigned ofrecord to: Symmorphix, Inc.
`
`The power of attorney in the prior application is to FINNEGAN, HENDERSON,
`FARABOW, GARRETT & DUNNER, L.L.P., Customer No. 22,852
`
`Since the power does not appear in the original declaration, a copy of the power in
`the prior application is enclosed.
`
`9. ~ Please address all correspondence to FINNEGAN, HENDERSON, FARABOW,
`GARRETT and DUNNER, L.L.P., Customer Number 22,852.
`
`10. ~ Also enclosed are an Information Disclosure Statement, Form PTO/SB/08, and
`one cited reference.
`
`Page 2 of 472
`
`
`
`Page 3 of 3
`
`PETITION FOR EXTENSION. If any extension of time is necessary for the filing of this
`application, including any extension in parent Application No. 10/101,863, filed March 16, 2002,
`for the purpose of maintaining copendency between the parent application and this application,
`and such extension has not otherwise been requested, such an extension is hereby requested, and
`the Commissioner is authorized to charge necessary fees for such an extension to our Deposit
`Account No. 06-0916. A duplicate copy of this paper is enclosed for use in charging the deposit
`account.
`
`FINNEGAN, HENDERSON, F ARABOW,
`GARRETT & D
`R, L.L.P.
`
`Dated: September 16, 2005
`
`FINNEGAN, HENDERSON, F ARABOW,
`GARRETT & DUNNER L.L.P.
`901 New York Avenue, N.W.
`Washington, D.C. 20001-4413
`(650) 849-6622
`
`EXPRESS MAIL LABEL NO.
`EV 708643040 US
`
`Page 3 of 472
`
`
`
`0
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`PATENT
`Customer Number 22,852
`Attorney Docket No. 9140.0016-02
`
`IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`Commissioner for Patents
`P.O. Box 1450
`Alexandria, VA 22313-1450 ·
`
`Prior Application Art Unit: 2823
`
`Prior Application Examiner: ESTRADA, Michelle
`
`SIR: This is a request for filing a
`D Continuation O Continuation-in-Part [2J Divisional Application under 37 C.F.R. § l .53(b)
`of pending prior Application No. 10/101,863 filed March 16, 2002, ofHongmei ZHANG,
`Mukundan NARASINHAN, Ravi B. MULLAPUDI, and Richard E. DEMARAY for BIASED
`PULSE DC REACTIVE SPUTTERING OF OXIDE FILMS.
`
`1.
`
`2.
`
`3.
`
`Enclosed is a complete copy of the prior application including the oath or
`Declaration and drawings, if any, as originally filed. I hereby verify that the
`attached papers are a true copy of prior Application No. 10/101,863 as originally
`filed on March 16, 2002, which is incorporated herein by reference.
`
`A Preliminary Amendment is enclosed.
`
`The filing fee is calculated on the basis of the claims existing in the prior
`application as amended in the Preliminary Amendment filed herewith.
`
`Page 4 of 472
`
`
`
`Page 2 of 3
`
`$300
`
`$500
`
`$200
`
`$ 300.00
`
`500.00
`
`200.00
`
`0
`
`0
`
`0
`
`0
`
`$ 1,000.00
`-
`$ 1,000.00
`
`0
`
`Basic Utility Application Filing Fee
`
`Search Fee
`
`Examination Fee
`
`Total Claims
`
`Number of Claims
`7 -
`2 -
`
`Basic
`
`Extra
`
`20
`
`3
`
`0 X $ 50
`
`0 X $200
`
`+$360
`
`Independent Claims
`LJ Presentation of Multiple Dep. Claim(s)
`
`Total Application Pages
`(specification, drawings, and printed
`sequence or computer listing)
`Subtotal
`
`Reduction by 1/2 if small entity
`
`TOTAL APPLICATION FILING FEE
`
`66
`
`If over 100 pages, add $250 for
`each additional 50 pages or
`fraction thereof.
`
`4. ~ The Commissioner is hereby authorized to charge the fee of$1,000.00 to Deposit
`Account No. 06-0916.
`
`5. ~ The Commissioner is hereby authorized to charge any fees which may be required
`including fees due under 37 C.F.R. § 1.16 and any other fees due under 37 C.F.R.
`§ 1.17, or credit any overpayment during the pendency of this application to
`Deposit Account No. 06-0916.
`
`6.
`
`7.
`
`8.
`
`[2J
`
`[2J
`
`[g].
`
`The prior application is assigned ofrecord to: Symmorphix, Inc.
`
`The power of attorney in the prior application is to FINNEGAN, HENDERSON,
`FARABOW, GARRETT & DUNNER, L.L.P., Customer No. 22,852
`
`Since the power does not appear in the original declaration, a copy of the power in
`the prior application is enclosed.
`
`9. ~ Please address all correspondence to FINNEGAN, HENDERSON, FARABOW,
`GARRETT and DUNNER, L.L.P., Customer Number 22,852.
`
`10. ~ Also enclosed are an Information Disclosure Statement, Form PTO/SB/08, and
`one cited reference.
`
`Page 5 of 472
`
`
`
`Page 3 of 3
`
`PETITION FOR EXTENSION. If any extension of time is necessary for the filing of this
`application, including any extension in parent Application No. 10/101,863, filed March 16, 2002,
`for the purpose of maintaining copendency between the parent application and this application,
`and such extension has not otherwise been requested, such an extension is hereby requested, and
`the Commissioner is authorized to charge necessary fees for such an extension to our Deposit
`Account No. 06-0916. A duplicate copy of this paper is enclosed for use in charging the deposit
`account.
`
`FINNEGAN, HENDERSON, F ARABOW,
`GARRETT & D
`R, L.L.P.
`
`Dated: September 16, 2005
`
`FINNEGAN, HENDERSON, F ARABOW,
`GARRETT & DUNNER L.L.P.
`901 New York Avenue, N.W.
`Washington, D.C. 20001-4413
`(650) 849-6622
`
`EXPRESS MAIL LABEL NO.
`EV 708643040 US
`
`Page 6 of 472
`
`
`
`. .1/
`
`.·:
`
`M-12245 US
`852923 vi
`
`Express Mail Label No.
`EL 941069152 US
`
`Biased Pulse DC Reactive Sputtering of Oxide Films
`
`Hongmei Zhang
`Mukundan Narasimhan
`Ravi Mullapudi
`Richard E. Demaray
`
`Background
`
`1. Field of the Invention
`
`[0001] The present invention relates to deposition of oxide and oxynitride films and, in
`
`particular, to deposition of oxide .and oxynitride films by pulsed DC reactive sputtering.
`
`2. Discussion of Related Art
`
`[0002]
`
`Deposition of insulating materials and especially optical materials is
`
`technologically important in several areas including production of optical devices and production
`
`of semiconductor devices. In semiconductor devices, doped alumina silicates can be utilized as
`
`· high dielectric insulators.
`
`[0003] The increasing prevalence of fiber optic communications systems has created an
`
`unprecedented demand for devices for processing optical signals. Planar devices such as optical
`
`waveguides, couplers, splitters, and amplifiers, fabricated on planar substrates, like those
`
`commonly used for integrated circuits, ~d configured to receive and process signals from
`
`optical fibers are highly desirable. Such devices hold promise for integrated optical and
`
`electronic signal processing on a single semiconductor-like substance.
`
`[0004] The basic design of planar optical waveguides and amplifiers is well known, as
`
`described, for example, in U, S. Patent Nos. 5,119,460 and 5,563,979 to Bruce et al., 5,613,995
`
`to Bhandarkar et al., 5,900,057 to Buchal et al., and 5,107,538 to Benton et al., to cite only a few.
`
`These devices, very generally, include a core region, typically bar shaped, of a certain refractive
`
`index surrounded by a cladding region of a lower refractive index. In the case of an optical
`
`amplifier, the core region includes a certain concentration of a dopant, typically a rare earth ion
`
`-1-
`
`BEST AVAILABLE COPY
`
`Page 7 of 472
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`
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`M-12245 US
`852923 vi
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`such as an erbium or praseodymium ion which, when pumped by a laser, :fluoresces, for
`
`example, in the 1550 nm and 1300 nm wavelength ranges used for optical communication, to
`
`amplify the optical signal passing through the core.
`
`[0005] As described, for example in the patents by Bruce et al., Bhandarkar et al, and Buchal et
`
`al., planar optical devices may be fabricated by process sequences including forming a layer of
`
`cladding material on a substrate; forming a layer of core material on the layer of cladding mater;
`
`patterning the core layer using a photolighotgraphic mask and an etching process to form a core
`
`ridge; and covering the core ridge with an upper cladding layer.
`
`[0006] The performance of.these planar optical devices depends sensitively on the. value and
`
`uniformity of the refractive index of the core region and of the cladding region, and particularly
`
`on the difrerence in refractive index, ~n, between t-he regions. Particularly for passiye devices
`such as waveguides, couplers, and splitters, ~n should be carefully controlled, for example to
`values within about 1 %, and the refractive index of both core and cladding need to be highly
`
`uniform, for some applications at the fewer than parts per thousand level. In the case of doped
`
`materials forming the core region of planar optical amplifiers, it is important that the dopant be
`
`uniformly distributed so as to avoid non-radiative quenching or radiative quenching, for example
`
`by upconversion. The refractive index and other desirable properties of the core and cladding
`
`regions, such as physical and chemical uniformity, low stress, and high density, depend, of
`
`course, on the choice of materials for the devices and on the processes by which they are
`
`fabricated.
`
`[0007) Because of their optical properties, silica and refractory oxides s_uch as Ah03, are good
`candidate materials for planar optical devices. Further, these oxides serve as suitable hosts for
`,,
`rare earth dopants used in optical amplifiers. A common material choice is so-called low
`
`temperature glasses, doped with alkali metals, boron, or phosphorous, which have the advantage
`
`ofrequiring lower processing temperatures. In addition, dopants are used to modify the
`
`refractive index. Methods such as flame hydrolysis, ion exchange for introducing alkali ions in
`
`glasses, sputtering, and various chemical vapor deposition processes (CVD) have been used to
`
`form films of doped glasses. However, dopants such as phosphorous and boron are hygroscopic,
`
`and alkalis are undesirable for integration with electronic devices. Control of uniformity of
`
`doping in CVD processes can be difficult and CVD deposited films can have structural defects
`
`-2-
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`Page 8 of 472
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`M-12245 US
`852923 vi
`
`leading to scattering losses when used to guide light. In addition, doped low temperature glasses
`
`may require further processing after deposition. A method for eliminating bubbles in thin films
`
`of sodium-boro-silicate glass by high temperature sintering is described, for example, in the '995
`
`patent to Bhandarkar et al.
`
`[0008] Typically, RF sputtering has been utilized for deposition of oxide dielectric films.
`
`However, RF sputtering utilizes ceramic targets which are typically formed of multiple smaller
`
`tiles. Since the tiles can not be made very large, there may be a large problem of arcing between
`
`tiles and therefore contamination of the deposited film due to this arcing. Further, the reactors
`
`required for RF sputtering tend to be rather complicated. In particular, the engineering of low
`
`capacitance efficient RF power distribution to the cathode is difficult in RF systems. Routing of
`
`low capacitance forward and return power into a vacuum vessel of the reaction chamber often
`
`exposes the power path in such a way that diffuse plasma discharge is allowed under some
`
`conditions of impedance tuning of the matching networks.
`
`[0009] Therefore, there is a need for new methods of depositing oxide and oxynitride films and
`
`for forming planar optical devices.
`
`I I I
`j
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`
`Summary
`
`[0010] In accordance with the-present invention, a sputtering reactor apparatus for depositing
`
`oxide and oxynitride films is presented. Further, methods for depositing oxide and oxynitride
`
`films for optical waveguide devices are also presented. A sputtering reactor according to the
`
`present invention includes a pulsed DC power supply coupled through a filter to a target and a
`
`substrate efoctrode coupled to an RF power supply. A substrate m~:mnted on the substrate
`
`electrode is therefore supplied with a bias from the RF power supply.
`
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`
`[0011] The target can be a metallic target made of a material to be deposited on the substrate. In
`
`some embodiments, the metallic target is formed from Al, Si and _various rare-earth ions. A
`
`target with an erbium concentration, for example, can be utilized to deposit a film that can be
`
`formed into a waveguide optical amplifier.
`
`[0012) A substrate can be any material and, in some embodiments, is a silicon wafer. In some
`
`-3-
`
`Page 9 of 472
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`
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`M-12245 US
`852923 vi
`
`embodiments, RF power can be supplied to the wafer. In some embodiments, the wafer and the
`
`electrode can be separated by an insulating glass.
`
`[0013) In some embodiments, up to about 10 kW of pulsed DC power at a frequency of between
`
`about 40 kHz and 350 kHz and a reverse pulse time ofup to about 5 µsis supplied to the target.
`
`The wafer can be biased with up to about several hundred watts of RF power. The temperature
`
`of the substrate can be controlled to within about 10° C and can vary from about -50° C to
`
`several hundred degrees C. Process gasses can be fed into the reaction chamber of the reactor
`
`apparatus. In some embodiments, the process gasses can include combinations of Ar, N2, 02,
`
`C2F6, CO2, CO and other process gasses.
`
`[0014] Several material properties of the deposited layer can be modified by adjusting the
`
`composition of the target, the compo~ition and flow rate of the process gasses, the ppwer
`
`I
`
`supplied to the target and the substrate, and the temperature of the substrate. For example, the
`
`index of refraction of the deposited layer depends on deposition parameters. Further, in some
`
`embodiments stress can be relieved on the substrate by depositing a thin film of material on a
`
`back side of the wafer. Films deposited according to the present invention can be utilized to
`
`form optical waveguide devices such as multiplexers and rare-earth doped amplifiers.
`
`[0015] These and other embodiments, along with examples of material layers deposited
`
`according to the present invention, are further described below with respect to the following
`
`figures.
`
`Brief Description of the Figures
`
`[0016] Figures IA and lB show a pulsed DC sputtering reactor according to the present
`
`invention .
`
`[0017) Figure 2 shows a planar view of target utilized in a reactor as shown in Figures lA and
`lB.
`
`[0018] Figure 3 shows a cross-section view of an example target utilized in a reactor as shown in
`
`Figures lA and IB.
`
`-4-
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`Page 10 of 472
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`M-12245 US
`· 852923 vi
`
`[0019] Figure 4 shows a flow chart of an embodiment of a process for depositing a film on a
`
`substrate according to the present invention.
`
`[0020] Figure 5 shows a hysterises curve of target voltage versus oxygen flow rates for an
`
`example target in an embodiment of a reactor according to the present invention.
`
`(0021) Figure 6 shows a photo-luminescence and lifetimes of a film deposited in a process
`
`according to the presei:it invention as a function of after deposition anneal temperature.
`
`[0022] Figure 7 shows the relationship between the index of refraction of a film as a function of
`
`deposited oxide layers according to the present invention and due to oxide build-up on the target.
`
`[0023] Figure 8 shows a graph of the index of refraction of a film deposited according to the
`
`present invention as a function of the aluminum content in a composite Al/Si target..
`
`(0024] Figure 9 shows .a graph of typical indices of refraction of material layers deposited
`
`according to the present invention.
`
`[0025] Figur~ 10 shows a table of indices of refraction for a silica layer deposited according to
`
`the present invention as a function of different process parameters.
`
`[0026] Figure 11 shows the refractive indices as a function of 0 2/ Ar ratio utilized in an Alumina
`process according to the present invention.
`
`[0027] Figure 12 shows the refractive indices as a function of DC pulsed power.frequency for an
`
`Alumina layer deposited according to the present invention.
`
`[0028) Figure 13 shows variation .in the refractive index over time during repeated depositions
`
`from a single target.
`
`[0029) Figure 14 shows variation in refractive index over time for repeated depositions from a
`
`target of another material layer according to the present invention.
`
`[0030] Figure 15 shows the variation refractive index over time for repeated depositions from a
`
`target of another material layer according to the present invention.
`
`[0031) Figure 16A through l6D shows a TEM film deposited according to the present invention.
`
`-5-
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`M-12245 US
`852923 vi
`
`[0032] Figure 17 shows the transparency of a film deposited according to the present invention.
`
`[003~] Figure 18 shows an uppercladding layer deposited according to the present invention
`
`over a multiple-waveguide structure such that the deposited layer is substantially planarized.
`
`[0034] Figure 19 illustrates the deposition of a film over a waveguide structure.
`
`[0035] Figures 20 and 21 illustrate different etch and deposition rates for deposition of films as a
`
`function of the surface angle of the film.
`
`[0036] Figure 22 illustrates calcul~tion of the planarizati_on time for a particular deposition
`
`process.
`
`[0037] Figures 23 through 25 through illus.trate adjustment of process parameters in order to
`
`achieve planarization of a film deposited over a waveguide structure according to the present
`
`invention.
`
`[0038] Figure 26 shows the gain characteristics of an erbium doped waveguide amplifier formed
`
`of films depositions according to the present invention.
`
`[0039] Figures 27 shows gain, insertion loss of a waveguide with an active core deposited
`
`according to the present invention.
`
`[0040} Figure 28 shows up-conversion constants, and lifetimes of the active core layer of Figure
`
`27 deposited according to the present invention.
`
`.[0041] Figure 29 shows drift in the index ofrefraction with subsequent depositions for films
`
`deposited from a target according to the present invention.
`
`[0042] Figure 30 shows drift in the photoluminescence with subsequent depositions according to
`
`the present invention.
`
`[0043] Figure 31 shows drift in the excited state lifetime with subsequent depositions according
`
`to the present invention.
`
`[0044] Figure 32 shows stabilization of the index ofrefraction in subsequent depositions.
`
`[0045) Figure 33 shows the index of refraction of a film formed from a pure silicon target as a
`
`-6-
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`Page 12 of 472
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`M-12245 US
`852923 vi
`
`function of the ratio of 0 2/N2 in the process gas.
`
`· [0046] In the figures, elements having the same designation have the same or similar function .
`
`.
`
`I
`
`l'
`
`Detailed Description
`
`(0047] Reactive DC magnetron sputtering of nitrides and carbides is a widely practiced
`
`technique, but the reactive ~c magnetron sputtering of nonconducting oxides is done rarely.
`
`Films such as aluminum oxide are almost impossible to deposit by conventional reactive DC
`
`magnetron sputtering due to rapid formation of insulating oxide layers on the target surface. The
`insulating surfaces charges up and result in arcing during process. This arcing can damage the
`
`power supply, produce particles and degrade the properties of deposited oxide films.
`
`[0048] RF sputtering of oxide films is discussed in Application Serial No. 09/903,050 (the '050
`
`J
`I .
`
`application) by Demaray etal., entitled "Planar Optical Devices and Methods for Their
`
`Manufacture," assigned to the same assignee as is the pres.ent invention, herein incorporated by
`
`reference in its entirety. Further, targets that can be utilized in a reactor according to the present
`
`invention are discussed in U.S. Application serial no. {Attorney Docket No. M-12247 US} (the
`'247 application), filed concurrently with the present disclosure, assigned to the same assignee as
`is the present invention, herein incorporated by reference in its entirety. A gain-flattened
`
`amplifier formed of films deposited according to the present invention are described in U.S.
`
`Application serial no. {Attorney Docket No. M-12652 US} (the '652 application), filed
`
`concurrently with the present disclosure, assigned to the same assignee as is the present
`
`invention, herein incorporated by reference in its entirety. Further, a mode size converter formed
`
`with films deposited according to the present invention is described in U.S. Application serial no. _
`
`{Attorney Docket No. M-12138 US} (the '138 application), filed concurrently with the present
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`disclosure, assigned to the same assignee as is the present invention, herein incorporated by
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`reference in its entirety.
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`[0049] Figure IA shows a schematic of a reactor apparatus 10 for sputtering of material from a
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`target 12 according to the present invention. In some embodiments, apparatus 10 may, for
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`M-12245 US
`852923 vi
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`example, be adapted from an AKT-1600 PVD (400 X 500 mm substrate size) system from
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`Applied Komatsu or an AKT-4300 (600 X 720 mm substrate size) system from Applied
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`Komatsu, Santa Clara, CA. The AKT-1600 reactor, for example, has three deposition chambers
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`connected by a vacuum transport chamber. These Komatsu reactors can be modified such that
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`pulsed DC power is Supplied to the target and RF power is supplied to the substrate during
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`deposition of a material film.
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`[0050) Apparatus IO includes a target 12 which is electrically coupled through a filter 15 to a
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`pulsed DC power supply 14. In some embodiments, target 12 is a wide area sputter source
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`target, which provides material to be deposited on substrate 16. Substrate 16 is positioned
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`parallel to and opposite target 12. Target 12 functions as a cathode when power is applied to it
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`artd is equivalently termed a cathode. Application of power to target 12 creates a plasma 53.
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`Substrate 16 is capacitively coup~ed to an electrode 17 through an insulator 54. Electrode 17 can
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`be coupled to an RF power supply 18. Magnet 20 is scanned across the top of target 12.
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`[0051) For pulsed reactive de magnetron sputtering, as performed by apparatus 10, the polarity
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`of the power supplied to target 12 by power supply 14 oscillates between negative and positive
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`potentials. During the positive period, the insulating layer on the surface of target 12 is
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`discharged and arcing is prevented. To .obtain arc free deposition, the pulsing frequency exceeds
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`a critical frequency that depend on target material, cathode current and reverse time. High
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`quality oxide films can be made using reactive pulse DC magnetron sputtering in apparatus 10.
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`(0052] Pulsed DC power supply 14 can be any pulsed DC pow~r supply, for example an AE
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`Pinnacle plus lOK by Advanced Energy, Inc. With this example supply, up to 10 kW of pulsed
`.
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`DC power can be supplied at a frequency of between O and 350 KHz. The reverse voltage is
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`10% of the negative target voltage. Utilizati<:>n of other power supplies will lead to different
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`power characteristics, frequency characteristics and reverse voltage percentages. The reverse
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`time on this embodiment of power supply 14 can be adjusted between O and 5 µs.
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`[0053] Filter 15 prevents the bias power from power supply 18 from coupling into pulsed DC
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`power supply 14. In some embodiments, power supply 18 is a 2 MHz RF power supply, for
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`example can be a Nova-25 power supply made by ENI, Colorado Springs, Co.
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`[0054] Therefore, filter 15 is a 2 MHz band rejection filter. In some embodiments, the band
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`M-12245 US
`852923 vi
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`width of the filter can be approximately 100 kHz. Filter 15, therefore, prevents the 2 MHz
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`power from the bias to substrate 16 from damaging power supply 18.
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`[0055] However, both RF and pulsed DC deposited films are not fully dense and most likely
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`have columnar structures. These columnar structures are detrimental for optical wave guide
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`applications due to the scattering loss caused by the structure. By applying a RF bias on wafer
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`16 during deposition, the deposited film can be dandified by energetic ion bombardment and the
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`columnar structure can be substantially eliminated.
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`[0056} In the AKT-1600 based system, for example, target 12 can have an active size of about
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`675.70 X 582.48 by 4 mm in order to deposit films on substrate 16 that have d_imension about
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`400 X 500 mm. The temperature of substrate 16 can be held at between -SOC and 500C. The
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`distance between target 12 and substrate 16 can be between about 3 and about 9 cm., Process gas
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`can be inserted into the chamb.er· of apparatus 10 at a rate. up to about 200 seem while the
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`pressure in the chamber of apparatus 10 can be held at between about . 7 and 6 millitorr. Magnet
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`20 provides a magnetic field of strength between about 400 and about 600 Gauss directed in the
`plane of target 12 and is moved across target 12 at a rate ofless than about 20-30 sec/scan. In
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`some embodiments utilizing the A.KT 1600 reactor, magnet 20 can be a race-track shaped
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`magnet with dimension about 150 mm by 600 mm.
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`[0057] A top down view of magnet 20 and wide area target 12 is shown in Figure 2. A film
`deposited on a substrate positioned on carrier sheet 17 directly opposed to region 52 of target 12
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`has good thickness unifonnity. Region 52 is the region shown in Figure lB that is exposed to a
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`uniform plasma condition. In some implementations, carrier 17 can be coextensive with region
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`52. Region 24 shown in Figure 2 indicates the area below which both physically and chemically
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`uniform deposition can be achieved, where physical and chemical unifonnity provide refractive
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`index uniformity, for example. Figure 2 indicates that region 52 of target 12 that provides
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`thickness uniformity is, in general, larger than region 24 of target 12 providing thickness and
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`· chemical uniformity. In optimized processes, however, regions 52 and 24 may be coextensive.
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`[0058) In some embodiments, magnet. 20 extends beyond area 52 in one direction, the Y
`direction in Figure 2, so that scanning is necessary in only one direction,-the X direction, to
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`provide a time averaged uniform magnetic field. As shown in Figures IA and IB, magnet 20
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`can be scanned over the entire extent of target 12, which is larger than region 52 of uniform
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`Page 15 of 472
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`M-12245 US
`852923 vi
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`sputter erosion. Magnet 20 is moved in a plane parallel to the plane of target 12.
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`[0059] The combination of a uniform target 12 with a target area 52 larger than the area of
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`substrate 16 can provide films of highly uniform thickness. Further, the material properties of
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`the film deposited can be highly uniform. The conditions of sputtering at the target surface, such
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`as the uniformity of erosion, the average temperature of the plasma at the target surface and the
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`equilibration of the target surface with the gas phase ambient of the process are uniform over a
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`region which is greater than or equal to the region to be coated with a uniform film thickness. In
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`addition, the region of uniform film thickness is greater than or equal to the region of the film
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`which is to have highly uniform optical properties such as index of refraction, density,
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`transmission or absorptivity:
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`[0060] Target 12 can be formed of any materials, but is typically metallic materials ~uch as, for
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`example, combinations of Al aIJ.d Si. Therefore, in some embodiments, target 12 includes a
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`metallic target material formed. from intermetalic compounds of optical elements such as Si, Al,
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`Er and Yb. Additionally, target 12 can be fom1ed, for example, from materials such as La, Yt,
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`Ag, Au, and Eu. To form optically active films on substrate 16, target 12 can include rare-earth
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`ions. In some embodiments of target 12 with rare earth ions, the rare earth ions can be pre(cid:173)
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`alloyed with the metallic host components to form intermetalics. See the '247 application.
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`[0061] In several embodiments of the invention, material tiles are formed. These tiles can be
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`mounted on a backing plate to form a target for apparatus 10. Figure 3A shows an embodiment
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`of target 12 formed with individual tiles 30mounted on a cooled backplate 25. In order to form
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`a wide area target of an alloy target material, the cop.solidated material of individual tiles 30
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`· should first be uniform to the grain size-of the powder from which it is formed. It also should be
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`formed into a structural material capable of forming and :finishing to a tile shape having a surface
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`roughness on the order of the powder size from which it is consolidated. A wide area sputter
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`cathode target can be formed from a close packed array of smaller tiles. Target 12, therefore,
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`may include any number of tiles 30, for example between 2 to 20 individual tiles 30. Tiles 30 are
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`finished to a size so as to provide a margin of non-contact, tile to tile, 29 in Figure 3A, less than
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`about 0.01 O" to about 0.020" or less than half a millimeter so as to eliminate plasma processes
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`between adjacent ones of tiles 30. The distance between tiles 30 of target 12 and the dark space
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`anode or ground shield 19, in Figure lB can be somewhat larger so as to provide non contact
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`assembly or provide for thermal expansion tolerance during process chamber conditioning or
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`Page 16 of 472
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`M-12245 US
`852923 vi
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`operation.
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`(0062] Several useful examples of target 12 that can be utilized in apparatus 10 according to the
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`present invention include the following targets compositions: (Si/Al/Er/Yb) being about
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`(57 .0/41.4/0.8/0.8), ( 48.9/49/1.6/0.5), (92/8/0/0), (60/40/0/0), (50/50/0/0), ( 65/35/0/0),
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`(70/30/0,0), and (50,48.5/1.5/0) cat. %, to list only a few. These targets can be referred to as the
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`0.8/0.8 target, the 1.6/.5 target, the 92-8 target, the 60-40 target, the 50-50 target;the 65-35 ·
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`target, the 70-30 target, and the 1.5