`U.S. Patent No. 7,811,421
`
`References cited herein:
`(cid:120) U.S. Pat. No. 7,811,421 (“’421 Patent”)
`
`(cid:120) U.S. Pat. No. 6,413,382 (“Wang”)
`
`(cid:120) A. A. Kudryavtsev, et al, Ionization relaxation in a plasma produced by a pulsed inert-gas
`discharge, Sov. Phys. Tech. Phys. 28(1), January 1983 (“Kudryavtsev”)
`
`(cid:120)
`
`‘421 Claims 9, 21, and 35
`
`Wang in view of Kudryavtsev
`
`[1pre]. A sputtering source comprising: Wang discloses a sputtering source.
`
`Wang at Title (“pulsed sputtering with a small
`rotating magnetron”)
`
`[1a] a) a cathode assembly comprising
`a sputtering target that is positioned
`adjacent to an anode; and
`
`Wang discloses a cathode assembly comprising a
`sputtering target that is positioned adjacent to an
`anode.
`
`‘421 Patent at 3:39-4:2 (“FIG. 1 illustrates a cross-
`sectional view of a known magnetron sputtering
`apparatus 100 having a pulsed power source 102. …
`The magnetron sputtering apparatus 100 also
`includes a cathode assembly 114 having a target
`116. … An anode 130 is positioned in the vacuum
`chamber 104 proximate to the cathode assembly
`114.”)
`
`Wang at 3:66-4:1 (“A grounded shield 24 … acts as
`a grounded anode for the cathode of the negatively
`biased target 14.”)
`
`Wang discloses a power supply that generates a
`voltage pulse between the anode and the cathode
`assembly that creates a weakly-ionized plasma and
`then a strongly-ionized plasma from the weakly-
`ionized plasma without an occurrence of arcing
`between the anode and the cathode assembly, an
`amplitude, a duration and a rise time of the voltage
`pulse being chosen to increase a density of ions in
`the strongly-ionized plasma
`
`Wang at Figs. 1, 6 and 7
`
`Wang at 7:58-61 (“… DC power supply 100 is
`connected to the target 14 … and supplies an
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`[1b] b) a power supply that generates a
`voltage pulse between the anode and
`the cathode assembly that creates a
`weakly-ionized plasma and then a
`strongly-ionized plasma from the
`weakly-ionized plasma without an
`occurrence of arcing between the anode
`and the cathode assembly, an
`amplitude, a duration and a rise time of
`the voltage pulse being chosen to
`increase a density of ions in the
`strongly-ionized plasma.
`
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`‘421 Claims 9, 21, and 35
`
`EXHIBIT C.15
`U.S. Patent No. 7,811,421
`Wang in view of Kudryavtsev
`
`essentially constant negative voltage to the target 14
`corresponding to the background power PB.”)
`
`Wang at 7:61-62 (“The pulsed DC power supply 80
`produces a train of negative voltage pulses.”)
`
`Wang at 3:66-4:1 (“A grounded shield 24 … acts as
`a grounded anode for the cathode of the negatively
`biased target 14.”) (emphasis added)
`
`Wang at 7:17-31 (“The background power level PB
`is chosen to exceed the minimum power necessary
`to support a plasma... [T]he application of the high
`peak power PP quickly causes the already existing
`plasma to spread and increases the density of the
`plasma.”)
`
`Wang at 7:19-25 (“Preferably, the peak power PP is
`at least 10 times the background power PB … and
`most preferably 1000 times to achieve the greatest
`effect of the invention. A background power PB of 1
`kW [causes] little if any actual sputter deposition.”)
`
`Wang at 7:31-39 (“In one mode of operating the
`reactor, during the background period, little or no
`target sputtering is expected. The SIP reactor is
`advantageous for a low-power, low-pressure
`background period since the small rotating SIP
`magnetron can maintain a plasma at lower power
`and lower pressure than can a larger stationary
`magnetron. However, it is possible to combine
`highly ionized sputtering during the pulses with
`significant neutral sputtering during the background
`period.”)
`
`Wang at 7:3-6 (“Plasma ignition, particularly in
`plasma sputter reactors, has a tendency to generate
`particles during the initial arcing, which may
`dislodge large particles from the target or
`chamber.”)
`
`Wang at 7:13-28 (“Accordingly, it is advantageous
`to use a target power waveform illustrated in FIG.
`6… As a result, once the plasma has been ignited at
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`‘421 Claims 9, 21, and 35
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`EXHIBIT C.15
`U.S. Patent No. 7,811,421
`Wang in view of Kudryavtsev
`
`the beginning of sputtering prior to the illustrated
`waveform…”)
`
`Wang at 7:47-49 (“The initial plasma ignition needs
`be performed only once and at much lower power
`levels so that particulates produced by arcing are
`much reduced.”)
`
`Wang at 7:28-30 (“…the application of the high
`peak power PP instead quickly causes the already
`existing plasma to spread and increases the density
`of the plasma”)
`
`Wang at 5:23-26 (“The illustrated pulse form is
`idealized. Its exact shape depends on the design of
`the pulsed DC power supply 80, and significant rise
`times and fall times are expected.”)
`
`The combination of Wang and Kudryavtsev
`discloses the voltage pulse generated between the
`anode and the cathode assembly excites atoms in the
`weakly-ionized plasma and generates secondary
`electrons from the cathode assembly, the secondary
`electrons ionizing a portion of the excited atoms,
`thereby creating the strongly-ionized plasma.
`
`See evidence cited in claim 1
`
`‘421 Patent at Fig. 6
`
`‘421 Patent at 15:56-61 (“Between time t1 and time
`t2, … the power 330 remain[s] constant as the
`weakly-ionized plasma 262 (FIG. 5B) is generated.
`… The power 336 delivered at time t2 is in the range
`of 0.01 kW to 100 kW.”)
`
`‘421 Patent at 16:32-34 (“In one embodiment, at
`time t5, … the power 350 is in the range of 1 kW to
`10 MW.”)
`
`‘421 Patent at 8:25-26 (“In one embodiment, the
`pressure in the chamber varies from about 10-3 to 10
`Torr.”)
`
`‘421 Patent at 1:44-46 (“Magnetron sputtering
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`9. The sputtering source of claim 1
`wherein the voltage pulse generated
`between the anode and the cathode
`assembly excites atoms in the weakly-
`ionized plasma and generates
`secondary electrons from the cathode
`assembly, the secondary electrons
`ionizing a portion of the excited atoms,
`thereby creating the strongly-ionized
`plasma.
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`‘421 Claims 9, 21, and 35
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`EXHIBIT C.15
`U.S. Patent No. 7,811,421
`Wang in view of Kudryavtsev
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`systems use magnetic fields that are shaped to trap
`and to concentrate secondary electrons, which are
`produced by ion bombardment of the target
`surface.”)
`
`Wang at 7:19-25 (“Preferably, the peak power level
`PP is at least 10 times the background power level
`PB, … most preferably 1000 times to achieve the
`greatest effects of the invention. A background
`power PB of 1 kW will typically be sufficient….”)
`
`Wang at 7:32-36 (“The SIP reactor is advantageous
`for a low-power, low-pressure background period
`since the small rotating SIP magnetron can maintain
`a plasma at a lower power and lower pressure than
`can a larger stationary magnetron.”)
`
`Wang at 7:36-39 (“However, it is possible to
`combine highly ionized sputtering during the pulses
`with significant neutral sputtering during the
`background period.”)
`
`Fu [incorporated by referenced in Wang] at 1:46-48
`(“Although the base pressure can be held to about
`10-7 Torr or even lower, the pressure of the working
`gas is typically maintained at between about 1 and
`1000 mTorr.”)
`
`Kudryavtsev at 34, right col, ¶ 4 (“[s]ince the effects
`studied in this work are characteristic of ionization
`whenever a field is suddenly applied to a weakly
`ionized gas, they must be allowed for when studying
`emission mechanisms in pulsed gas lasers, gas
`breakdown, laser sparks, etc.”)
`
`Kudryavtsev at Figs. 1 and 6
`
`Kudryavtsev at 31, right col, ¶ 7 (“The behavior of
`the increase in ne with time thus enables us to
`arbitrarily divide the ionization process into two
`stages, which we will call the slow and fast growth
`stages. Fig. 1 illustrates the relationships between
`the main electron currents in terms of the atomic
`energy levels during the slow and fast stages.”)
`
`Kudryavtsev at 31, right col, ¶ 6 (“For nearly
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`‘421 Claims 9, 21, and 35
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`EXHIBIT C.15
`U.S. Patent No. 7,811,421
`Wang in view of Kudryavtsev
`
`stationary n2 [excited atom density] values … there
`is an explosive increase in ne [plasma density]. The
`subsequent increase in ne then reaches its maximum
`value, equal to the rate of excitation [equation
`omitted], which is several orders of magnitude
`greater than the ionization rate during the initial
`stage.”)
`
`Kudryavtsev at Abstract (“in a pulsed inert-gas
`discharge plasma at moderate pressures… [i]t is
`shown that the electron density increases explosively
`in time due to accumulation of atoms in the lowest
`excited states.”)
`
`Kudryavtsev at 30, Equation 1
`
`Kudryavtsev at 30, right col, last ¶ (“…n2, and ne are
`the atomic densities in the …first excited states and
`the electron density, respectively;… (cid:69)2e [is] the rate
`coefficient[]…”)
`
`It would have been obvious to combine Wang and
`Kudryavtsev, which states, “[s]ince the effects
`studied in this work are characteristic of ionization
`whenever a field is suddenly applied to a weakly
`ionized gas, they must be allowed for when studying
`emission mechanisms in pulsed gas lasers, gas
`breakdown, laser sparks, etc.” Kudryavtsev at 34,
`right col, ¶ 4. Because Wang applies pulses that
`“suddenly generate an electric field,” one of
`ordinary skill reading Wang would have been
`motivated to consider Kudryavtsev to better
`understand the effects of applying Wang’s pulse.
`
`[17pre]. A sputtering source
`comprising:
`
`Wang discloses a sputtering source.
`
`See evidence cited in claim 1 preamble
`
`[17a] a) a cathode assembly comprising
`a sputtering target that is positioned
`adjacent to an anode;
`
`Wang discloses a cathode assembly comprising a
`sputtering target that is positioned adjacent to an
`anode.
`
`See evidence cited in claim [1a]
`
`[17b] b) a power supply that generates Wang discloses a power supply that generates a
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`‘421 Claims 9, 21, and 35
`
`EXHIBIT C.15
`U.S. Patent No. 7,811,421
`Wang in view of Kudryavtsev
`
`a voltage pulse between the anode and
`the cathode assembly that creates a
`weakly-ionized plasma and then a
`strongly-ionized plasma from the
`weakly-ionized plasma without an
`occurrence of arcing between the anode
`and the cathode assembly, an amplitude
`and a rise time of the voltage pulse
`being chosen to increase a density of
`ions in the strongly-ionized plasma;
`and
`
`[17c] c) a substrate support that is
`positioned adjacent to the sputtering
`target; and
`
`voltage pulse between the anode and the cathode
`assembly that creates a weakly-ionized plasma and
`then a strongly-ionized plasma from the weakly-
`ionized plasma without an occurrence of arcing
`between the anode and the cathode assembly, an
`amplitude and a rise time of the voltage pulse being
`chosen to increase a density of ions in the strongly-
`ionized plasma.
`
`See evidence cited in claim [1b]
`
`Wang discloses a substrate support that is positioned
`adjacent to the sputtering target.
`
`Wang at 3:63-66 (“A pedestal electrode 18 supports
`a wafer 20 to be sputter coated in planar opposition
`to the target 14 across a processing region 22.”)
`
`[17d] d) a bias voltage source having
`an output that is electrically plasma.
`coupled to the substrate support.
`
`Wang discloses a bias voltage source having an
`output that is electrically plasma. coupled to the
`substrate support.
`
`Wang at Fig. 1
`
`Wang at 4:32-34 (“[A]n RF bias power supply is
`connected to the pedestal electrode 18 to create a
`negative DC self-bias on the wafer 20”)
`
`The combination of Wang and Kudryavtsev
`discloses the voltage pulse generated between the
`anode and the cathode assembly excites atoms in the
`weakly-ionized plasma and generates secondary
`electrons from the cathode assembly, the secondary
`electrons ionizing a portion of the excited atoms,
`thereby creating the strongly-ionized plasma.
`
`See evidence cited in claim 17
`
`See evidence cited in claim 9
`
`21. The sputtering source of claim 17
`wherein the voltage pulse generated
`between the anode and the cathode
`assembly excites atoms in the weakly-
`ionized plasma and generates
`secondary electrons from the cathode
`assembly, the secondary electrons
`ionizing a portion of the excited atoms,
`thereby creating the strongly-ionized
`plasma.
`
`[34pre]. A method for high deposition
`rate sputtering, the method comprising:
`
`Wang discloses a method for high deposition rate
`sputtering.
`
`Wang at Title (“pulsed sputtering with a small
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`‘421 Claims 9, 21, and 35
`
`EXHIBIT C.15
`U.S. Patent No. 7,811,421
`Wang in view of Kudryavtsev
`
`rotating magnetron”)
`
`Wang at 7:19-25 (“Preferably, the peak power Pp is
`at least 10 times the background power PB, more
`preferably at least 100 times, and most preferably
`1000 times to achieve the greatest effect of the
`invention. A background power PB of 1 kW will
`typically be sufficient to support a plasma with the
`torpedo magnetron and a 200 mm wafer although
`with little if any actual sputter deposition.”)
`
`Wang at 7:36-39 (“However, it is possible to
`combine highly ionized sputtering during the pulses
`with significant neutral sputtering during the
`background period.”)
`
`Wang discloses generating a voltage pulse between
`the anode and the cathode assembly comprising a
`sputtering target, the voltage pulse creating a
`weakly-ionized plasma and then a strongly-ionized
`plasma from the weakly-ionized plasma without an
`occurrence of arcing between the anode and the
`cathode assembly.
`
`See evidence cited in claim [1a]
`
`See evidence cited in claim [1b]
`
`Wang discloses adjusting an amplitude and a rise
`time of the voltage pulse to increase a density of
`ions in the strongly-ionized plasma.
`
`See evidence cited in claim [1b]
`
`The combination of Wang and Kudryavtsev
`discloses the applying the voltage pulse to the
`cathode assembly generates excited atoms in the
`weakly-ionized plasma and generates secondary
`electrons from the sputtering target, the secondary
`electrons ionizing the excited atoms, thereby
`creating the strongly- ionized plasma.
`
`See evidence cited in claim 34
`
`See evidence cited in claim 9
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`[34a] a) generating a voltage pulse
`between the anode and the cathode
`assembly comprising a sputtering
`target, the voltage pulse creating a
`weakly-ionized plasma and then a
`strongly-ionized plasma from the
`weakly-ionized plasma without an
`occurrence of arcing between the anode
`and the cathode assembly; and
`
`[34b] b) adjusting an amplitude and a
`rise time of the voltage pulse to
`increase a density of ions in the
`strongly-ionized plasma.
`
`35. The method of claim 34 wherein
`the applying the voltage pulse to the
`cathode assembly generates excited
`atoms in the weakly-ionized plasma
`and generates secondary electrons from
`the sputtering target, the secondary
`electrons ionizing the excited atoms,
`thereby creating the strongly- ionized
`plasma.
`
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`EXHIBIT C.15
`U.S. Patent No. 7,811,421
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