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`Samsung Electronics Co., Ltd. v. Demaray LLC
`Samsung Electronic's Exhibit 1033
`Exhibit 1033, Page 1
`
`

`

`U.S. Patent
`
`
`
`
`Nov. 3, 1998
`
`
`
`
`Sheet 1 of 15
`
`
`
`5,830,327
`
`
`
`
`
`
`
`
`
`
`
`Ex. 1033, Page 2
`
`Ex. 1033, Page 2
`
`

`

`U.S. Patent
`
`
`
`
`Nov. 3, 1998
`
`
`
`
`Sheet 2 of 15
`
`
`5,830,327
`
`
`
`
`
`
`
`
`50|DETERMINE OPTIMAL EROSION
`
`
`
`
`PROFILE TO PROVIDE DESIRED
`
`
`THICKNESS UNIFORMITY
`
`
`AND INVENTORY
`
`
`
`
`
`
`92
`
`
`
`
`
`DETERMINE TRACK SHAPE
`
`
`
`THAT PROVIDES OPTIMAL
`
`
`EROSION PROFILE
`
`
`
`
`
`
`
`
`
`
`
`EXPRESS DESIRED TRACK SHAPE
`
`
`
`
`AS PIECEWISE LINEAR SEGMENTS;
`
`
`
`CALCULATED EROSION PROFILE
`
`
`
`
`
`
`
`
`58
`
`
`
`ALTER
`
`TRACK
`
`
`SHAPE
`
`
`
`
`ACCEPTABLE FIT TO
`
`
`
`OPTIMAL EROSION PROFILE?
`
`
`
`
`YES
`
`
`
`60
`
`
`
`
`
`LAYOUT MAGNET ARRAY
`
`
`
`
`
`
`
`
`
`
`
`66
`
`
`
`
`
`
`
`CALCULATE PLASMA TRACK
`
`64
`
`
`
`
`ALTER
`ACCEPTABLE FIT TO
`
`
`
`
`DESIRED PLASMA TRACK?
`MAGNET
`
`
`
`
`
`
`ARRAY
`
`
`
`
`
`YES
`
`
`
`DONE
`
`
`
`
`FIG. 2
`
`Ex. 1033, Page 3
`
`Ex. 1033, Page 3
`
`

`

`U.S. Patent
`
`
`
`
`Nov. 3, 1998
`
`
`
`
`Sheet 3 of 15
`
`
`5,830,327
`
`
`
`r
`
`SUBSTRATE
`
`
`
`
`10
`
`r —————» dA
`
`
`
`oore
`
`
`
`
`
`
`ryan
`
`{6
`M
`| to <a?— \#¢'
`
`
`
`
`32~\
`
`
`
`|
`
`
`7 TARGET
`
`|e
`alz
`412
`
`
`
`N
`
`x
`
`
`
`32
`
`
`—
`
`
`
`
`
`
`FIG. 3
`
`Ex. 1033, Page 4
`
`Ex. 1033, Page 4
`
`

`

`
`U.S. Patent
`
`
`
`
`Nov. 3, 1998
`
`
`
`
`Sheet 4 of 15
`
`5,830,327
`
`
`
`
`
`f)
`
`ot
`
`oy {ASp
`
`
`FIG. 4
`
`Ex. 1033, Page 5
`
`

`

`
`
`
`
`
`
`
`
`
`
`FIG.5
`
`U.S. Patent 5,830,327
`
`
`
`
`
`Ex. 1033, Page 6
`
`Ex. 1033, Page 6
`
`

`

`
`U.S. Patent
`
`
`
`Nov. 3, 1998
`
`
`
`
`Sheet 6 of 15
`
`
`5,830,327
`
`
`
`80
`
`
`
`70
`
`
`
`60
`
`
`
`
`
`0.1
`
`0.0
`
`
`
`measured
`
`
`
`
`
` FIG.6RADIALPOSITION(mm)
`
`
`
`
`
`50
`
`40
`
`30
`
`
`
`20
`
`
`
`10
`
` -----—-predicted
`
`—0.6
`
`0.
`
`0
`
`0
`
`0
`
`—0.1
`
`
`(Www) Hid3d NOISONS
`
`
`
`Ex. 1033, Page 7
`
`Ex. 1033, Page 7
`
`

`

`U.S. Patent
`
`Nov. 3, 1998
`
`Sheet 7 of 15
`
`5,830,327
`
`(mm) FIG.7 °
`
`50
`
`40
`
`50RADIUS
`
`N
`
`°
`
`2
`o
`co
`mM
`
`2
`Oo
`NS
`m
`
`2
`2
`°
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`o
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`=
`n
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`°
`o
`¥)
`
`Ex. 1033, Page 8
`
`Ex. 1033, Page 8
`
`

`

`UM1O—@—
`
`OoLe
`
`
`
`
`(Vv) SSSNMOIHL dalIsSod3a
`
`008z
`
`
`
`00ZZ
`
`
`
`0092
`
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`
`
`U.S. Patent
`
`
`
`
`
`
`Nov. 3, 1998
`
`
`
`
`Sheet 8 of 15
`
`5,830,327
`
`
`
`6L
`
`o0¢¢
`
`o0ce
`
`000s:
`
`
`
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`
`
`
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`
`
`
`
`(ww)SNTdVY
`
`8‘ls
`
`Ex. 1033, Page 9
`
`
`
`00rE
`
`00¢72
`
`
`
`0022
`
`
`
`Ex. 1033, Page 9
`
`

`

`U.S. Patent
`
`
`
`
`Nov. 3, 1998
`
`
`
`
`Sheet 9 of 15
`
`
`5,830,327
`
`
`
`
`
`4050
`
`
`
`30
`
`
`
`20 115kWh
`
`
`
`RADIUS(mm)FIG,9
`
`
`
`
`
` 10 --A--
`
`
`
`1600
`
`Ex. 1033, Page 10
`
`1800
`Oo
`Oo
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`
`
`
`(Vv) SSINMOIHL Galisod3ad
`
`1700
`
`
`
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`
`©N
`
`Ex. 1033, Page 10
`
`

`

`U.S. Patent
`
`
`
`
`Nov. 3, 1998
`
`
`
`
`Sheet 10 of 15
`
`
`5,830,327
`
`
`
`
`
` 2-_
`
`S
`
`
`
`NOISOWS 3ALLW13y
`
`{
`
`
`
`
`
`Ex. 1033, Page 11
`
`Ex. 1033, Page 11
`
`

`

`U.S. Patent
`
`
`
`
`Nov. 3, 1998
`
`
`
`
`Sheet 11 of 15
`
`
`
`5,830,327
`
`
`
`&EN
`
`e
`
`”>2
`
`
`
`Oo
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`t
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`—
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`©s
`
`+
`
`©©
`
`Ex. 1033, Page 12
`
`Ex. 1033, Page 12
`
`

`

`U.S. Patent
`
`
`
`
`Nov. 3, 1998
`
`
`
`
`Sheet 12 of 15
`
`
`5,830,327
`
`
`
`iP
`
`
`
`80
`
`
`
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`
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`0.0
`
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`
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`
`Ex. 1033, Page 13
`
`Ex. 1033, Page 13
`
`

`

`U.S. Patent
`
`
`
`
`
`Nov. 3, 1998
`
`
`
`
`
`
`Sheet 13 of 15
`
`(mm)
`
`5,830,327
`
`
`
`Ex. 1033, Page 14
`
`Ex. 1033, Page 14
`
`

`

`U.S. Patent
`
`
`
`
`Nov. 3, 1998
`
`
`
`
`Sheet 14 of 15
`
`
`5,830,327
`
`
`
`
`
`4050
`
`
`
`
`30RADIUS(mm) FIG.14
`
`
`
`20
`
`Oo
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`
`
`re)
`Oo
`
`
`
`
`Ex. 1033, Page 15
`
`
`
`
`———~——predicted
`specified
`
`
`
`
`
`
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`
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`SSSNMOIHL SALLV13Y
`
`Ex. 1033, Page 15
`
`

`

`U.S. Patent
`
`
`
`
`Nov. 3, 1998
`
`
`
`
`Sheet 15 of 15
`
`
`5,830,327
`
`
`
`
`
`SPUTTERING
`
`
`
`
`SOURCE 1
`
`
`
`
`
`
`FIG. 15
`
`
`
`Ex. 1033, Page 16
`
`Ex. 1033, Page 16
`
`

`

`
`1
`METHODS AND APPARATUS FOR
`
`
`
`
`SPUTTERING WITH ROTATING MAGNET
`
`
`
`SPUTTER SOURCES
`
`
`FIELD OF THE INVENTION
`
`
`
`
`
`
`
`
`This invention relates to deposition of sputtered films on
`
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`
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`substrates and, more particularly, to rotating magnet sput-
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`
`
`tering methods and apparatus which providelongtargetlife,
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`
`
`broad erosion patterns and depositional thickness unifor-
`
`mity.
`
`
`2
`
`
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`
`
`typical process conditions has not been acceptable. Decreas-
`
`
`
`
`
`
`ing the target-to-substrate distance can degrade deposition
`
`
`
`
`
`
`uniformity, unless the erosion profile is redesigned to com-
`
`pensate.
`
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`
`
`
`Another problem in current sputter coating systemsis that
`
`
`
`
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`
`
`
`certain areas of the target, especially the center region,
`
`
`
`
`
`
`experience no sputtering. Redeposition from sputtered
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`
`
`atoms turned back to the target by gas scattering can
`
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`accumulate in the nonsputtered regions. The accumulated
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`redeposition may be a poor conductor and may promote a
`
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`
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`
`
`low voltage arc breakdown, with consequent undesirable
`
`
`
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`
`
`
`generation of particles that can contaminate the substrate
`BACKGROUND OF THE INVENTION
`
`
`
`
`
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`
`
`
`
`being coated. In the prior art, sputtering of the center region
`
`
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`has been achieved by complex mechanical motion of the
`Sputter deposition, also known as sputter coating, is a
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`magnetstructure relative to the target.
`technique for depositing thin films of desired materials on a
`
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`An apparently related phenomenon is the growth of
`substrate such as, for example, a magnetic disk for a hard
`
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`poorly conducting nodules on the target surface when sput-
`disk drive or a semiconductor wafer. In general, inert gas
`
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`tering from a carbon target, as is used in magnetic disk
`ions from a gas plasma are accelerated towardatarget of the
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`coating. In production runs, it may be necessary to halt the
`material to be deposited. Free atoms of the target material
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`machine from time to time to clean the carbontargets.
`are expelled when the ions collide with the target. A portion
`of the free atoms form a thin film on the surface of the
`
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`USS. Pat. No. 4,995,958 issued Feb. 26, 1991 to Anderson
`substrate.
`
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`et al. discloses a sputtering apparatus with a rotating magnet
`
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`array having a geometry which produces a selected erosion
`One well knownsputtering technique is magnetron sput-
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`profile on the target. The selected erosion profile is typically
`tering. Magnetron sputtering uses a magnetic field to con-
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`nearly constant with radius over a selected region. The
`centrate the sputtering action. Magnets are positioned
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`centerline of the magnet structure is described by an equa-
`behind the target, and magnetic field lines penetrate the
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`tion. The disclosed track equation is not fully general and
`target and form arcs over its surface. The magnetic field
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`does not describe all possible plasma tracks. In particular,
`helps to confine free electrons in an area near the surface of
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`the track equation cannot be used to describe an erosion
`the target. The resulting increased concentration of free
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`profile that extends to the center of the target.
`electrons produces a high density of inert gas ions and
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`enhancesthe efficiency of the sputtering process.
`USS. Pat. No. 5,252,194 issued Oct. 12, 1993 to Demaray
`
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`et al. discloses a magnetron sputter source which includes a
`Both fixed and movable magnet structures have been
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`rotating magnet assembly that is stated to produce uniform
`utilized in magnetron sputtering. In a typical structure uti-
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`target erosion across the full target surface, including the
`lizing a moving magnet, the target is circular and the magnet
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`center. The target surface may be planar or dished.
`structure rotates with respect to the center of the target. In
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`U.S. Pat. No. 5,314,597 issued May 24, 1994 to Harra
`either configuration,
`the sputtering process produces an
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`discloses a sputtering apparatus including a rotatable magnet
`erosion pattern on the target that is nonuniform. To avoid
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`configuration for obtaining a desired sputter target erosion
`contaminating the substrate, sputtering must be stopped
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`profile and a desired film characteristic. In developing the
`before the erosion pattern has consumedthefull thickness of
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`magnet configuration, a heart-shaped plasmatrack having an
`the target material at any point. The target must be replaced
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`erosion profile near the desired profile is utilized. A static
`when the erosion at any point approaches a substantial
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`erosion test, with the magnetstructure not rotating, is run to
`fraction of the target’s initial thickness. Thus in a given
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`develop a measurable static erosion groovein the target. The
`production process, only a certain numberof substrates can
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`depth of erosion is measured at various points on the target
`be coated from one target. The sputtering apparatus must be
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`in such a way as to quantify the erosion along radial spokes
`shut down during a target change and is nonproductive
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`at fixed values of polar angle. The magnet configuration is
`during this period, with a consequent undesirable and costly
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`then adjusted to provide an erosion profile that is closer to
`decrease in average throughput.
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`the desired profile. The process is repeated until the desired
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`Three basic approaches may be used to increase the
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`profile is achieved. The *597 patent discloses a relationship
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`numberof substrates a target can coat before the target must
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`for finding thickness uniformity given an erosion profile, but
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`be replaced. The thickness of the target can be increased to
`increase the volume of material to be removed from the
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`does not disclose how to find an erosion profile given a
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`desired thickness variation.
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`target before it is spent. Second, the shape of the erosion
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`USS. Pat. No. 5,120,417 issued Jun. 9, 1992 to Takahashi
`profile can be altered by design to make greater use of the
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`et al. discloses a magnetron sputtering apparatus including a
`target volume. Finally, the target-to-substrate distance can
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`rotating magnetstructure which is stated to erode the central
`be decreased so as to capture a larger percentage of the
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`region of the target and thereby reduce the number of
`material sputtered from the target. However, performance
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`particulates deposited on the substrate.
`may be degraded as the thickness of the target is increased.
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`USS. Pat. No. 5,130,005 issued Jul. 14, 1992 to Hurwitt et
`In particular, the field strength at the target surface may be
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`decreased, decreasing the efficiency of sputtering. Also,
`al. discloses a magnetron sputter coating apparatus including
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`deposition uniformity may show greater variation over the
`a rotating magnet structure comprising a stack of flexible
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`life because of the variation in target-to-substrate
`plasticized ferrite and several auxiliary magnets which pro-
`target
`distance.
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`vide a desired plasma track. The magnetstructure is rotated
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`in a cavity filled with water. The surface of the target is
`The design and physical realization of a suitable erosion
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`machined to a cylindrically symmetric shape which is
`profile has remained a problem in magnetron source design.
`thicker near the outer rim.
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`Sources have been designed having uniform erosion over
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`USS. Pat. No. 5,188,717 issued Feb. 23, 1993 to Broad-
`much of the target, which maximizes use of the target
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`volume, but the corresponding deposition uniformity under
`bent et al. discloses a magnetron sputtering apparatus
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`5,830,327
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`Ex. 1033, Page 17
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`Ex. 1033, Page 17
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`

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`5,830,327
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`3
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`including a rotating magnet assembly which produces a
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`plasma track comprising a closed curvethatis stated to have
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`the shape of a kidney bean. The closed curve is generated in
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`part by a spiral curve generated by the same equation
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`disclosed by Andersonet al. in U.S. Pat. No. 4,995,958. The
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`magnet assembly is simultaneously rotated about a center of
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`rotation and is causedto oscillate radially with respect to the
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`center of rotation so as to produce erosion over the entire
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`target surface.
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`US. Pat. No. 5,248,402 issued Sep. 28, 1993 to Ballentine
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`et al. discloses a magnetron sputtering system including a
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`rotating magnet assembly that
`is characterized as apple
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`shaped. The disclosed magnet assemblyis stated to produce
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`uniform coatings and erosion over the entire surface of the
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`target.
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`USS. Pat. No. 5,417,833 issued May 23, 1995 to Harra et
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`al. discloses a magnetron sputtering apparatus including a
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`rotating magnet assembly and a pair of separately driven
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`stationary electromagnets. The electromagnets are used to
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`increase target utilization at its center and to compensate for
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`the change in shapeof the target and distance from the target
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`to the substrate with depletion.
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`Magnetron sputtering systems which utilize a rotating
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`magnet assembly are also disclosed in U.S. Pat. No. 4,444,
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`643 issued Apr. 24, 1984 to Garrett; U.S. Pat. No. 4,714,536
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`issued Dec. 22, 1987 to Freeman et al.; U.S. Pat. No.
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`4,746,417 issued May 24, 1988 to Ferenbachet al.; U.S. Pat.
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`No. 5,047,130 issued Sep. 10, 1991 to Akaoet al.; U.S. Pat.
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`No. 5,194,131 issued Mar. 16, 1993 to Anderson; and U.S.
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`Pat. No. 5,320,728 issued Jun. 14, 1994 to Tepman.
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`All of the known prior art magnetron sputtering systems
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`utilizing rotating magnet assemblies have had one or more
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`disadvantages, including but not limited to short target life,
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`nonuniform depositional
`thickness, variations in perfor-
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`mance over the life of the target, contamination of the
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`substrate, complex mechanical drive structures and a
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`requirement for nonplanar target surfaces.
`SUMMARYOF THE INVENTION
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`According to the present invention, a magnetron sputter-
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`ing source is provided for forming a sputtered film on a
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`substrate in a magnetron sputtering apparatus. The magne-
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`tron sputtering source comprises a target having a surface
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`from which material is sputtered and a magnet assembly that
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`is rotatable about an axis of rotation with respect to the
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`target. The magnet assembly produces on the target an
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`erosion profile that approximates a solution to an equation of
`the form
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`b
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`f K@re(r)r'dr’= t(r)
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`where e(r') is the erosion profile, t(r) is a desired radial
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`thickness distribution of the sputtered film, K(,r) is a
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`function depending on the sputter geometry and process
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`conditions, r is the radial position on the substrate, r' is the
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`radial position on the target, and a and b are the radial limits
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`of erosion on the target. Although for many applications it
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`may be desirable to choose t(r)=constant to specify uniform
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`thickness, the invention also includes cases wheret(r) varies
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`in a specified non-uniform fashion across the substrate.
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`According to another aspect of the invention, a method is
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`provided for configuring a rotatable magnet assembly for
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`use in the magnetron sputtering apparatus. The magnetron
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`sputtering apparatus includes a target having a surface from
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`4
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`which material is sputtered to form a sputtered film on a
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`substrate. The method comprisesthe steps of determining an
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`erosion profile on the target that approximates a solution to
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`an equation of the form
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`b
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`f K@re(r)r'dr’= t(r)
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`10
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`15
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`25
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`35
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`40
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`where e(r') is the erosion profile, t(r) is a desired radial
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`thickness distribution of the sputtered film, K(,r) is a
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`function depending on the sputter geometry and process
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`conditions, r is the radial position on the substrate, r' is the
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`radial position on the target, and a and b are the radial limits
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`of erosion on the target, and determining a magnet structure
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`for the rotatable magnet assembly that produces an accept-
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`able approximation to the erosion profile e(r'). Although for
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`many applications it may be desirable to choose t(r)=
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`constant to specify uniform thickness,
`the invention also
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`includes cases where t(r) varies in a specified non-uniform
`fashion across the substrate.
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`According to another aspect of the invention, a magnetron
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`sputtering source is provided for forming a sputtered film on
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`a substrate in a magnetron sputtering apparatus. The mag-
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`netron sputtering source comprises a target having a surface
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`from which material is sputtered and a magnet assembly that
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`is rotatable about an axis of rotation with respect to the
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`target. The magnet assembly produces on the surface of the
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`target a plasma track having a shape characterized by a pair
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`of symmetrical lobes, a deeply indented first inward cusp
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`located near the axis of rotation and a moderately indented
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`second inward cusp. Thefirst and second cusps are located
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`on opposite sides of the plasma track. Each of the lobes has
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`a relatively long section of substantially constant radius with
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`respect to the axis of rotation.
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`According to another aspect of the invention, a magnetron
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`sputtering source is provided for forming a sputtered film on
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`a substrate in a magnetron sputtering apparatus. The mag-
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`netron sputtering source comprises a target having a surface
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`from which material is sputtered and a magnet assembly that
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`is rotatable about an axis of rotation with respect to the
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`target. The magnet assembly produces on the target an
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`erosion profile characterized by a relatively deep first cir-
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`cular groove near an outer periphery of the target, a rela-
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`tively shallow second circular groove near the center of the
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`target and an intermediate region between the first and
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`second grooves. The intermediate region has a shallower
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`erosion depth than the first and second grooves.
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`According to another aspect of the invention, a magnetron
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`sputtering source is provided for forming a sputtered film on
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`a substrate in a magnetron sputtering apparatus. The mag-
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`netron sputtering source comprises a target having a surface
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`from which material is sputtered and a magnet assembly that
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`is rotatable about an axis of rotation with respect to the
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`target. The magnet assembly and the target producea radial
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`thickness distribution of the sputtered film on the substrate
`that is uniform to better than about +5% for a source-to-
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`substrate distance of less than about 35 millimeters.
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`According to another aspect of the invention, a method is
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`provided for configuring a rotatable magnet assembly for
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`use in a magnetron sputtering apparatus including a target
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`having a surface from which material is sputtered to form a
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`sputtered film on a substrate. The method comprises the
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`steps of determining an erosion profile on the target that
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`produces a desired radial thickness distribution of the sput-
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`tered film on the substrate and a desired inventory of the
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`sputtered material on one or more substrates, determining a
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`Ex. 1033, Page 18
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`Ex. 1033, Page 18
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`

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`5,830,327
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`5
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`plasma track on the surface of the target that produces an
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`acceptable approximation to the erosion profile and deter-
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`mining a magnetstructure for the rotatable magnet assembly
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`that produces an acceptable approximation to the plasma
`track.
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`According to another aspect of the invention, a magnetron
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`sputtering apparatus is provided. The magnetron sputtering
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`apparatus comprises a first magnetron sputtering source for
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`forming a sputtered film on a first surface of a substrate and
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`a second magnetron sputtering source for forming a sput-
`tered film on a second surface of the substrate. The first
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`magnetron sputtering source includesa first target having a
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`surface from which material is sputtered and a first magnet
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`assembly that is rotatable about an axis of rotation with
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`respect to the first target. The second magnetron sputtering
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`source includes a second target having a surface from which
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`material is sputtered and a second magnet assembly that is
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`rotatable about an axis of rotation with respect to the second
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`target. The first and second magnet assemblies produce on
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`the surfaces of the first and second targets plasma tracks,
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`each having a shape characterized by a pair of symmetrical
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`lobes, a deeply indented first inward cusp located near the
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`axis of rotation and a moderately indented second inward
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`cusp. The first and second cusps are located on opposite
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`sides of the plasmatrack. Each of the lobes hasa relatively
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`long section of substantially constant radius with respect to
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`the axis of rotation. The magnetron sputtering apparatus
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`further includes a vacuum system for producing a vacuum in
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`regions between each target surface and the substrate.
`BRIEF DESCRIPTION OF THE DRAWINGS
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`For a better understanding of the present invention,ref-
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`erence is made to the accompanying drawings, which are
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`incorporated herein by reference and in which:
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`FIG. 1 is a simplified schematic diagram of a rotating
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`magnet sputtering system;
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`FIG. 2 is a flow diagram that illustrates the process for
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`configuring a rotating magnet structure in accordance with
`
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`the invention;
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`FIG. 3 is a schematic diagram showing the geometrical
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`parameters involvedin calculating the erosion profile on the
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`target;
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`FIG. 4 is a plan view of a first embodimentofa rotating
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`magnet assembly in accordance with the invention;
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`FIG. 5 is a schematic plan view of one half of a plasma
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`tion;
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`FIG. 6 is a graph of erosion depth as a function of radial
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`position for a copper target, showing optimal, measured and
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`predicted erosion profiles;
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`FIG. 7 is a graph of deposited thickness as a function of
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`radius for a chromium target;
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`FIG. 8 is a graph of deposited thickness as a function of
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`radius for a magnetic alloy target;
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`FIG. 9 is a graph of deposited thickness as a function of
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`radius for a carbon target;
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`FIG. 10 is a graph of erosion depth as a function of radial
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`position, showing a comparison of the optimized ideal
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`erosion profile and the predicted erosion profile for a second
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`embodiment in accordance with the invention;
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`FIG. 11 is a schematic plan view of one half of the center
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`line of a plasmatrack for the second embodimentin accor-
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`dance with the invention;
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`FIG. 12 is a graph of erosion depth as a function of radial
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`position, showing a comparison of the optimized ideal
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`6
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`erosion profile and the predicted erosion profile for a third
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`embodiment in accordance with the invention;
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`FIG. 13 is a schematic plan view of one half of the center
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`line of a plasma track for the third embodiment in accor-
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`dance with the invention;
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`FIG. 14 is a graph of relative thickness as a function of
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`radius, showing a comparison of the ideal radial thickness
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`variation and the predicted radial thickness variation for the
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`third embodiment in accordance with the invention; and
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`FIG. 15 is a block diagram of a sputter coating system
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`having two opposed sputtering sources.
`DETAILED DESCRIPTION
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`A simplified schematic diagram of a rotating magnet
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`sputter coating system is shown in FIG. 1. A substrate 10,
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`such as for example a magnetic disk,
`is positioned in a
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`vacuum chamber 12. A rotating magnet sputter source 20
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`includes a sputtering target 22 of a material to be deposited
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`on substrate 10, a rotating magnet assembly 24, and a
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`rotation motor 30 which causes the rotating magnet assem-
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`bly 24 to rotate about an axis of rotation 32 with respect to
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`target 22. A magnet array in rotating magnet assembly 24
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`produces magnetic fields which penetrate target 22 and form
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`arcs over a surface 26 of target 22 facing substrate 10. The
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`target 22 is cooled by a target cooling system 28.
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`The magnetic field helps to confine free electrons in an
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`area near the surface 26 of the target. The increased con-
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`centration of free electrons produces high densities of inert
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`gas ions, typically argon, and enhancestheefficiency of the
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`sputtering process. In particular, the region of most intense
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`ionization forms a closed loop plasma track on the surface
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`26 of target 22. The configuration of the plasma track is
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`discussed in detail below. As the rotating magnet assembly
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`24 rotates, the plasma track follows the instantaneous posi-
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`tion of the rotating magnet assembly and sputters areas of
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`the target.
`Important characteristics of the source
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`performance, including the volumeoferosion through target
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`life and depositional thickness uniformity on the substrate
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`10, depend on the detailed shape of the plasmatrack.
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`The present invention provides rotating magnet sputter
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`sources that have a broad erosion pattern and relatively
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`small source-to-substrate distances for extended target life.
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`The sputter sources of the invention also have good depo-
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`sitional thickness uniformity on the substrate. Good depo-
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`sitional thickness uniformity is typically less than +5% and
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`preferably less than +3%.
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`It is useful to define the term “inventory” as used in the
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`disk coater business to quantify the total thickness that can
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`be deposited on substrates during target life. The units are
`usually millions of angstroms (M A). For chromium, where
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`the film thickness on each substrate is relatively large,
`desirable inventory can be more than 15 M Aand preferably
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`more than 18 M A.
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`According to one aspect of the invention, a method for
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`configuring rotating magnet sputter sources that have the
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`above desirable characteristics is provided. The basis of the
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`method is to define,
`typically by iterative optimization
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`techniques,a target erosion profile that is calculated to yield
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`a desired depositional thickness distribution. A plasma track
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`shape is then generated that is predicted to produce the
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`optimized target erosion profile to sufficient accuracy. A
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`magnet structure is then designed to produce the desired
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`track shape. The plasma track design utilizes magnetostatic
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`modeling software such as “Amperes” (Integrated Engineer-
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`ing Software, Winnipeg, Canada).
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`The design methodis illustrated in the flow diagram of
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`FIG. 2. The foundation of the design methodis to determine
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`10
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`15
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`20
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`25
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`30
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`35
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`45
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`50
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`55
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`60
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`65
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`Ex. 1033, Page 19
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`Ex. 1033, Page 19
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`

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`5,830,327
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`7
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`an optimal erosion profile subject to the condition that it
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`produce approximately a desired depositional thickness uni-
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`formity on a substrate located a known distance from the
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`target surface (step 50). A prescribed inner diameter of the
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`erosion profile, a prescribed outer diameter, and a fixed
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`target-to-substrate distance also constrain the erosion shape.
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`The proper plasma track to achieve the optimal erosion
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`profile is inferred from the erosion profile.
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`Stable methods of solving