Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 1 of 30
`
`
`
`
`Exhibit 9
`
`
`
`
`
`
`
`
`

`

`ΙΙΙΙΙΙ·ΙΙΙΙΝΙΙΙΙΐηΐΙΗηΐ1ΙΙΙΙΙΙΙΙΙΜΙΙΙ
`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 2 of 30
`US005603816A
`5,603,816
`United States Patent [wj
`[ii] Patent Number:
`Demaray et al.
`Feb. 18, 1997
`[45] Date of Patent:
`
`[54] SPUTTERING DEVICE AND TARGET WITH
`COVER TO HOLD COOLING FLUID
`
`[75] Inventors: Richard E. Demaray, Portola Valley;
`Manuel Herrera, San Mateo; David E.
`Berkstresser, Los Gatos, all of Calif.
`
`[73] Assignee: Applied Materials, Inc., Santa Clara,
`Calif.
`
`[21] Appl. No.: 461,822
`Jun. 5,1995
`[22] Filed:
`
`“Diffusion Bonding of Ti-6A1-4V Alloy: Metallurgical
`Aspects and Mechanical Properties,” Ed. D. J. Stephenson,
`published in Diffusion Bonding 2, pp. 144—157.
`Korman, et al., “Research Study of Diffusion Bonding of
`Refractory Materials, Columbium and Tantalum,” Army
`Materials and Mechanics Research Center, Nov. 10, 1967,
`pp. 1-27.
`S. Pineau, et al., “The Investigation and Production of
`Titanium-Tantalum Junctions Diffusion Bonded at High
`Temperature (855° C. to 920° C.), etc.,” Royal Aerospace
`Establishment, Library Translation 2180, Jan. 1990, pp.
`3-34.
`
`Related U.S. Application Data
`
`Primary Examiner—iAaron Weisstuch
`Attorney, Agent, or Firm—Janis Biksa
`
`[62] Division of Ser. No. 157,763, Nov. 24, 1993, Pat. No.
`5,433,835.
`[51] Int. CI.6 ................................................. C23C 14/34
`[52] U.S. Cl................................. 204/298.07; 204/298.08
`[58] Field of Search ....................... 204/298.07, 298.08,
`204/298.09
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`12/1971 Lester et al............................ 204/298.09
`3,630,881
`5/1976 McLeod ................................ 204/192.12
`3,956,093
`7/1978 Rainey .................................. 204/298.12
`4,100,055
`9/1978 Love et al.............................. 204/298.19
`4,116,806
`4,166,018
`8/1979 Chapin .................................. 204/192.12
`4,175,030 11/1979 Love et al.............................. 204/298.18
`3/1982 Nishiyama et al.................... 204/298.09
`4,318,796
`(List continued on next page.)
`FOREIGN PATENT DOCUMENTS
`1-147061
`6/1989 Japan .................................. 204/298.09
`3-140464
`6/1991 Japan .................................. 204/298.09
`1/1992 Japan .................................. 204/298.07
`4-26760
`WO90/13137 11/1990 WIPO ................................... 204/298.2
`
`OTHER PUBLICATIONS
`“Influence of Surface Preparation on the Diffusion Welding
`of High Strength Aluminum Alloys,” Ed. D. J. Stephenson,
`published in Diffusion Bonding 2, pp. 101-110.
`
`ABSTRACT
`[57]
`A target, target backing plate, and cover plate form a target
`plate assembly. The sputtering target assembly includes an
`integral cooling passage. A series of grooves are constructed
`in either the target backing plate or the target backing
`cooling cover plate, which are then securely bonded to one
`another. The sputtering target can be a single monolith with
`a target backing plate or can be securely attached to the
`target backing plate by one of any number of conventional
`bonding methods. Tantalum to titanium, titanium to titanium
`and aluminum to titanium, diffusion bonding can be used.
`
`The target plate assembly completely covers and seals
`against a top opening of a sputtering processing chamber.
`Cooling liquid connections are provided only from the
`perimeter of the target assembly. When a top vacuum
`chamber seals the side opposite the pressure chamber, the
`pressure on both sides of the target assembly is nearly
`equalized. Large thin target assemblies, such as large flat
`plates used for flat panel displays can be sputtered effec­
`tively and uniformly without adverse sputtering effects due
`to target deflection or cooling deficiencies.
`
`The energized target assembly is protected from adjacent
`components by overlapping insulators to prevent accidents
`and isolate the target assembly from other components. An
`electrical connection to the target assembly remains uncon­
`nected until a vacuum is produced in the top chamber.
`
`2 Claims, 18 Drawing Sheets
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 3 of 30
`
`5,603,816
`Page 2
`
`U.S. PATENT DOCUMENTS
`4,405,436
`9/1983 Kobayashi et al................... 204/298.16
`4,430,190
`2/1984 Eilers et al........................... 204/298.12
`4,444,643
`4/1984 Garrett ................................ .. 204/298.2
`4,491,509
`1/1985 Krause ................................ 204/192.12
`4,500,409
`2/1985 Boys et al............................ 294/298.03
`4,564,435
`1/1986
`Wickersham ......................
`204/298.12
`4,569,745
`2/1986
`Nagashima..........................
`204/298.12
`4,680,061
`7/1987 Lamont, Jr. ......................... ........ 165/1
`4,714,536 12/1987 Freeman et al....................... . 204/298.2
`4,826,584
`5/1989 dos Santos Pereiro Ribeiro
`
`204/298.09
`
`4,839,011
`6/1988 Ramalingam et al............... 204/192.38
`4,904,362
`2/1990 Gaertner et al...................... 204/192.12
`4,978,437 12/1990 Wirz............................. ...... 204/192.23
`5,096,562
`3/1992 Boozenny et al............. ...... 204/298.22
`5,130,005
`7/1992 Hurwitt et al................. ...... 204/192.12
`5,171,415
`12/1992 Miller et al.................... ..... 204/298.09
`5,180,478
`1/1993 Hughes ........................ ...... 204/298.09
`5,203,980
`4/1993 Cremer et al.................. ...... 204/298.08
`5,244,556
`9/1993 Inoue .................................. 204/192.12
`5,259,941
`11/1993 Munz .................................. 204/298.09
`5,382,344
`9/1995 Hosokawa et al............. ........ 204/298.2
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 4 of 30
`U.S. Patent
`
`Feb. 18,1997
`
`Sheet 1 of 18
`
`5,603,816
`
`(PRIOR ART)
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 5 of 30
`U.S. Patent
`
`Feb. 18,1997
`
`Sheet 2 of 18
`
`5,603,816
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 6 of 30
`U.S. Patent Feb. 18,1997 Sheet 3 of 18
`
`5,603,816
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 7 of 30
`U.S. Patent
`
`Feb. 18, 1997
`
`Sheet 4 of 18
`
`5,603,816
`
`55
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 8 of 30
`U.S. Patent
`5,603,816
`
`Feb. 18, 1997
`
`Sheet 5 of 18
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 9 of 30
`U.S. Patent Feb. is, 1997 sheet 6 of 18
`5,603,816
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 10 of 30
`U.S. Patent
`5,603,816
`
`Feb. 18,1997
`
`Sheet 7 of 18
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 11 of 30
`U.S. Patent
`
`Feb. 18,1997
`
`Sheet 8 of 18
`
`5,603,816
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 12 of 30
`U.S. Patent Feb. 18,1997 Sheet 9 of 18
`
`5,603,816
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 13 of 30
`U.S. Patent
`5,603,816
`
`Sheet 10 of 18
`
`Feb. 18,1997
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 14 of 30
`U.S. Patent
`
`Sheet 11 of 18
`
`Feb. 18,1997
`
`5,603,816
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 15 of 30
`U.S. Patent
`
`Feb. 18,1997
`
`Sheet 12 of 18
`
`5,603,816
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 16 of 30
`U.S. Patent
`
`Feb. 18,1997
`
`Sheet 13 of 18
`
`5,603,816
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 17 of 30
`U.S. Patent
`
`Feb. 18,1997
`
`Sheet 14 of 18
`
`5,603,816
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 18 of 30
`U.S. Patent
`5,603,816
`
`Sheet 15 of 18
`
`Feb. 18,1997
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 19 of 30
`U.S. Patent
`
`Feb. 18,1997
`
`Sheet 16 of 18
`
`5,603,816
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 20 of 30
`U.S. Patent
`5,603,816
`
`Sheet 17 of 18
`
`Feb. 18,1997
`
`205
`
`200
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 21 of 30
`U.S. Patent
`5,603,816
`
`Sheet 18 of 18
`
`Feb. 18, 1997
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 22 of 30
`
`5,603,816
`
`1
`SPUTTERING DEVICE AND TARGET WITH
`COVER TO HOLD COOLING FLUID
`
`This application is a divisional application of prior U.S.
`application Ser. No. 08/157,763, filed on Nov. 24,1993, now
`U.S. Pat. No. 5,433,835.
`
`5
`
`FIELD OF THE INVENTION
`This invention relates to planar magnetron sputtering
`targets and more specifically to a structure and method for
`cooling the sputtering target and a structure and method for
`holding such a target being cooled.
`
`BACKGROUND OF THE INVENTION
`Sputtering describes a number of physical techniques
`commonly used in, for example, the semiconductor industry
`for the deposition of thin films of various metals such as
`aluminum, aluminum alloys, refractory metal silicides, gold,
`copper, titanium-tungsten, tungsten, molybdenum, tantalum
`and less commonly silicon dioxide and silicon on an item (a
`substrate), for example a wafer or glass plate being pro­
`cessed. In general, the techniques involve producing a gas
`plasma of ionized inert gas “particles” (atoms or molecules)
`by using an electrical field in an evacuated chamber. The
`ionized particles are then directed toward a “target” and
`collide with it. As a result of the collisions, free atoms or
`groups of ionized atoms of the target material are released
`from the surface of the target, essentially converting the
`target material to its gas phase. Most of the free atoms which
`escape the target surface condense and form (deposit) a thin
`film on the surface of the object (e.g. wafer, substrate) being
`processed, which is located a relatively short distance from
`the target.
`One common sputtering technique is magnetron sputter­
`ing. When processing wafers using magnetron sputtering, a
`magnetic field is used to concentrate sputtering action in the
`region of the magnetic field so that sputtering occurs at a
`higher rate and at a lower process pressure. The target itself
`is electrically biased with respect to the wafer and chamber,
`and functions as a cathode. Objectives in engineering the
`cathode and its associated a magnetic field source include
`uniform erosion of the target and uniform deposition of pure
`target material on the wafer being processed. During sput­
`tering, if magnets generating a magnetic field are stationary
`at a location, then continuous sputtering consumes the
`sputtering target thickness at that location quickly and
`generates hot spots at the locations of sputtering. To avoid
`contaminating the process, sputtering is stopped before the
`non-uniform sputtering wear pattern has consumed the full
`thickness of the target material at any point. If any point on
`the target plate behind the target were to be reached,
`sputtering of the target backing plate material (often copper)
`would occur, contaminating the vacuum chamber and the
`wafer being processed with the target backing material
`(copper). Because of the non-uniform pattern of target
`utilization, conventionally sputtering is usually stopped
`when a large percentage of the target still remains.
`As the target erodes, the distance between the target
`surface (which is eroding away) and the substrate being
`sputtered is slowly increasing. The change in the distance
`between the target surface and the substrate being sputtered
`creates a change in the qualities of the sputtered material
`deposited and its uniformity. When large areas such as glass
`plates are being deposited, variations in the thickness of
`deposited sputtered material are measurable and, may be
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`unacceptable if the change in the target thickness detrimen­
`tally affects the deposition of the target material on the
`substrate being deposited.
`In generating the gas plasma and creating ion streams
`impacting on the cathode, considerable energy is used. This
`energy must be dissipated to avoid melting or nearly melting
`the structures and components involved. Common tech­
`niques used for cooling sputtering targets are shown in
`FIGS. 1 and 2. One technique as used by many prior art
`sputtering devices is to pass water or other cooling liquid
`through a fixed internal passage of the sputtering target. As
`shown in FIG. 2, a first opening such as a hose 35 supplies
`water or other cooling liquid to a target backing plate 33
`where it passes through cavities or passages of the backing
`plate and out a second hose 36. The target 34 is therefore
`cooled. To complete the picture of FIG. 2, the sputtering
`chamber 30 includes a object substrate support structure 32
`on which the substrate to be deposited 31 rests. In this
`configuration the sputtering target is completely immersed
`in the process environment. A water-to-vacuum seal is often
`needed to prevent the water or other cooling liquid from
`leaking out of its passages. A magnetron sputtering cathode
`as described by Carlos dos Santos Pereiro Ribeiro in his U.S.
`Pat. No. 4,826,584 for a magnetron sputtering cathode is
`typical of the prior art showing cooling line attachments
`hidden behind the sputtering target and attached to the back
`of the target to pass liquid through structures adjacent to the
`target. While a magnet is not shown in FIG. 2, commonly
`these devices have stationary or rotating magnets to assist in
`directing the ion flow and controlling the primary sputtering
`location.
`Another technique which is commonly used which has
`eliminated the vacuum-to-water seal problem is shown in
`FIG. 1. A processing chamber 20 supports a sputtering table
`26 supporting substrate 25 to be sputter coated in close
`proximity to a target 24. The sputtering chamber 20 includes
`a circumferential top flange on which a target assembly 22
`rests. The target assembly 22 consisting of a target backing
`plate 23 and the target 24 completely covers the flange of the
`processing chamber 20 and a seal is made between the
`processing chamber and outside ambient air at the flange
`surface. A cooling chamber 21 encloses the top of the target
`assembly 22. A stationary magnet or a magnet moving
`through a path as depicted by the dashed lines. 28 is located
`closely adjacent to the back of the target backing plate 23.
`The magnet 27 as it is moved in a magnet sweep path by a
`magnet sweep mechanism (not shown) causes the movable
`magnet 27 to move in the magnet sweep zone as shown by
`the dashed lines 28 together with the magnet 27. The magnet
`and portions of the magnet sweep mechanism, in this
`configuration, are immersed in cooling liquid which is
`circulated through the chamber behind the target to ensure
`cooling of the target.
`In these configurations the target backing plate 23 is
`subjected to a strong vacuum pressure on the processing side
`(less than 1 torr) with a positive pressure of as much as
`several atmospheres on the cooling side. The actual pressure
`on the cooling side depends on the volume of coolant needed
`to cool the target and the diameter of the piping through
`which it needs to move to provide enough cooling to
`maintain acceptable temperatures on the sputtering target.
`To avoid short-circuiting the flow of coolant through the
`chamber (from the inlet immediately by the shortest path to
`the discharge), often distribution manifolds or flow directing
`restrictions are placed in the path of the coolant to minimize
`short-circuiting and maximize cooling.
`The weight of the water or other cooling liquid in the
`cooling chamber must also be supported by the target
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 23 of 30
`
`5,603,816
`
`3
`backing plate and target. To obtain maximum thermal con­
`duction between the cooling liquid and the target backing
`plate, it is necessary that the flow regime in the cooling
`chamber 21 be such that any fluid boundary layer formed at
`and near the back of the target backing plate 23 be mini­
`mized or eliminated. Therefore, laminar cooling flow is not
`sufficient, the flow must be in the turbulent range to maxi­
`mize heat transfer between the fluid target and the fluid.
`Higher fluid pressures are needed to generate the fluid
`velocities required for turbulent flow resulting in higher
`pressures in the cooling chamber 21.
`For small sputtering targets, the target backing plate and
`target can be built to be quite massive to resist deflections
`due to the differential pressures between the vacuum and the
`processing chamber 20 and the ambient air pressure plus
`fluid pressure in the cooling chamber 21. When the size of
`the target and target backing plate become large because the
`area to be coated is quite large, as might be done for a flat
`glass panel to be used in a flat panel display of a computer
`or television screen, the thickness of the target and target
`backing plate must be substantially increased to avoid
`unacceptable deflections. When a magnetron is used, sput­
`tering is most effective when the magnets are just behind the
`surface of the sputtering target. Increasing the distance
`between the surface of the sputtering target and any magnets
`used for magnetron sputtering behind the target (by increas­
`ing target thickness) substantially decreases the effect of the
`magnets on sputtering, or conversely, much more powerful
`magnets need to be used in order to be sure that the magnet
`field is effective through the thickness of the target and its
`backing plate.
`The deflection of the target and target backing plate under
`the differential pressure between the processing chamber
`and the cooling chamber causes the target and target backing
`plate to bow substantially. Many targets are attached to their
`target backing plates using a relative ineffective soldering or
`brazing technique. The bowing of the target backing plate
`and target creates an enormous stress in the solder or brazing
`material, or in the target material if it is softer, such that the
`probability of delamination or separation of the target from
`the target backing plate is greatly increased. In instances
`where solder or low temperature brazing has been used, a
`separation between the target and target backing plate at one
`point acts as a nucleus for a propagating defect. Once a
`pinhole surface defect forms, hot process gases can and
`often do find their way into such pinhole surface openings to
`progressively melt the solder and brazing compounds
`located there. When sufficient melting and/or separation has
`occurred, the target will actually drop off the target backing
`plate, ruining the process and requiring complete replace­
`ment of the target, if not a complete cleaning of the process
`chamber.
`Methods that have been used in the past to attempt to
`overcome these difficulties include explosion bonding, fric­
`tion welding or roll bonding of the target to its backing plate.
`In these processes there is a large non-uniform thermal or
`mechanical gradient to which the target and target backing
`plate are subjected. The microstructure of the various pieces
`is affected by the stress induced by thermal gradients or
`mechanical deflections and the. dimensions of the pieces
`change. Subsequent processing (machining and or thermal
`stress reduction techniques) must often be used to arrive at
`a target-target backing plate assembly that is dimensionally
`stable without warpage under the thermal cycling of sput­
`tering.
`The disadvantages of the existing sputtering target sys­
`tems as described above continue to inhibit the wide use of
`
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`sputtering as an efficient and cost-effective means for apply­
`ing surface coatings.
`SUMMARY OF THE INVENTION
`This invention relates to an improved configuration for a
`sputtering target and sputtering target backing plate. This
`configuration overcomes many of the drawbacks of the
`previous configurations and provides a structure and method
`to improve sputtering coverage and sputter large areas such
`as glass plates. In particular, large targets are required when
`stationary, full coverage deposition is required with high
`film quality for large substrates.
`The new configuration includes a processing chamber
`having a top circumferential flange surface. A sputtering
`target assembly is supported on the flange. The target
`assembly includes a target separate or integral with a target
`backing plate. In a monolithic (integral) configuration the
`target (e.g. aluminum and its alloys) and target backing plate
`can be a single piece of material into which O-ring grooves
`and other fixtures are machined to seal with the process
`chamber. In other instances the target material is separate
`from the target backing plate and is secured to the target
`backing plate using one of several commonly known joining
`techniques such as soldering, welding, or brazing. Addi­
`tional techniques for joining the target to the target backing
`plate according to this invention include bonding the target
`to its backing plate by use of diffusion bonding, by filler-
`metal, solid state, or liquid phase diffusion bonds.
`A cooling cover plate is firmly attached (bonded) to the
`back (top) of the target backing plate. The cooling cover
`plate must be tightly joined with the back of the target
`backing plate so that a tight seal is created for the cooling
`fluid. The cooling cover plate has cavities or grooves therein
`which provide a path for cooling fluid in which to flow. The
`cooling fluid cavities or grooves are configured in such a
`way as to distribute the cooling liquid flow over a substantial
`area of the target backing plate so as to provide a maximum
`cooling or heating effect over the whole plate. The grooves
`are machined or cast into the side of the cooling cover plate
`facing the target backing plate. The grooves or cavities have
`intermediate fins or walls. When the ends of these fins or
`groove walls are secured to the backing plate, they help
`maintain the dimensions of the cooling passages over the
`wide span of the cooling cover plate. In this way cooling
`fluid pressure in the cooling passages does not cause bowing
`of the cooling cover plate or the target and its target backing
`plate.
`The cooling cover plate can be joined to the target backing
`plate by any reliable means. However, it has been found that
`in order to reliably join the ends of the fins or intermediate
`walls of the cooling passage cavities or grooves to the target
`backing plate, it is necessary to provide a strong bond such
`as achieved by using a structural type adhesive, diffusion
`bonding, or brazing. It is important that the coefficient of
`thermal expansion of the target backing plate and its cover
`be closely matched. If not closely matched, then the shear
`stress associated with differential thermal expansion
`between the pieces causes bond failure. The differential
`strain between the target backing plate and a cooling cover
`plate of different materials, can be minimized by using pins
`at intermediate locations across the field between the edges
`of the plates. Screws or bolts at intermediate locations can
`also establish and assure that de-bonding does not take
`place.
`When using a structural type adhesive such as a nitrile
`epoxy adhesive, the surfaces to be bonded are cleaned and
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 24 of 30
`
`5,603,816
`
`5
`treated (roughened) to improve the adherence of the nitrile
`epoxy. The adhesive is precisely located on its respective
`bonding surfaces by being attached to a carrying screen or
`mesh. In accordance with good workmanship practices, the
`adhesive is placed on the mesh only at those locations
`corresponding to places between the cover plate and target
`backing plate where joining (bonding) is desired. The target
`backing plate and cooling cover plate are then pressed
`against each other with a predetermined pressure and heated
`to a predetermined temperature to assure the bonding of the
`pieces. Once the nitrile epoxy has set, a very strong bond is
`created between the cooling cover plate and the target
`backing plate such that differential pressures of several
`atmospheres can be applied without failure of the epoxy
`bond.
`The cooling cover plate can also be joined to the target
`backing plate using diffusion bonding techniques as dis­
`cussed below for bonding a separate target material to its
`backing plate.
`The cooling cover plate can also be a cast (formed) in
`place prepreg unit. Wax or other material with a low melting
`point can be formed into the shape (pattern) of the desired
`cooling flow passages on the back of the target backing
`plate. A fluid dam formed around the edge of the plate retains
`a casting material, such as prepreg—a castable structural
`epoxy that can be reinforced with various forms, tapes and
`fabrics (e.g., aramid fiber, glass, nylon, etc.) poured over the
`backing plate to form the cooling passages and insulate the
`target within the edges of the plate. Once the castable
`material sets, openings are made to the fluid passage and the
`assembly is heated to above the melting (or fluidizing)
`temperature of the pattern material so that the wax (or other
`pattern material) can be removed leaving cooling fluid
`passages in the shape of the pattern.
`Alternately, cooling water passages and grooves can also
`be provided in the target backing plate. The cooling cover
`plate is then a flat piece to bond over the cooling passages
`in the target backing plate.
`The target, target backing plate, and cooling cover plate
`make up a target assembly which is placed over the sput­
`tering chamber. When the target assembly is made in a
`configuration with a rigid cross section or reinforced to
`minimize bending, sputtering can take place while the target
`carries the load of the differential pressure between ambient
`conditions and the vacuum of the processing chamber.
`Alternatively, a top chamber, enclosing a magnet can be put
`in position and sealed to the top of the target assembly.
`When sputtering is desired the pressures in both the sput­
`tering chamber and the top chamber are reduced substan­
`tially and nearly equally. The target assembly then acts as a
`diaphragm separating two chambers of nearly equal pres­
`sure. The cooling fluid flowing through the cooling passages
`in the target assembly is isolated from both of the vacuum
`chambers. The strong bond between the target backing plate
`and the fins of the cooling cover plate reduces, if not
`completely eliminates, the deflection of the target assembly
`and target due to cooling fluid pressures.
`A magnet sweeping mechanism placed in the dry top
`chamber does not need to overcome the resistance of fluid as
`it would if it were immersed in fluid. Further, since the target
`assembly is acting as a diaphragm sealing two chambers of
`nearly identical pressure, the target assembly can be made
`very thin to decrease the distance of the magnets from the
`target face.
`The target assembly, in its present target size of 510
`mmx600 mm, however, does not require the top chamber to
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`6
`be under vacuum for the system to operate properly because
`the deflecting loads due to vacuum from the process side
`chamber are small and the coolant loads are all internal to
`the target assembly.
`Many types of high-intensity magnets reduce their mag­
`netic field strength at elevated temperatures. Using a con­
`figuration according to this invention, unlike previous con­
`figurations where the magnets are immersed in the hot
`cooling fluid, the magnets’ temperature increases very little,
`if at all, due to the sputtering process. The magnets are
`located in the top evacuated chamber and there is virtually
`no heat flow to the magnets by conduction and heat flow
`from the target assembly to the magnets by radiation will be
`quite minuscule as the cooling cover plate face of the target
`assembly will have a maximum temperature substantially
`identical with that of the average cooling fluid temperature,
`e.g. 50° C. At such temperatures, radiation heat transfer is
`negligible. In addition, because the target assembly is elec­
`trically charged, an electrical insulating sheet is often placed
`over and bonded to the backside of the cooling cover plate.
`This further reduces any heat transfer from the target assem­
`bly to the magnets.
`The electrically charged target assembly should be iso­
`lated from the sputtering process chamber and the top
`chamber as well as from operator contact. Insulating rings
`placed above, below and outside of the target assembly
`provide such insulation. A high purity water or other cooling
`fluid is used so that there is a negligible current loss through
`the cooling passages. An insulating hose is used to connect
`to the cooling/heating fluid source(s).
`The cooling fluid inlet and outlet flows can be routed
`through a plastic (acrylic, polycarbonate, etc.) manifold, or
`hose fittings with quick disconnect type fittings may be
`attached directly to the target backing plate. The plastic
`manifold is bolted to the target backing plate and provides
`insulation, preventing an operator from contacting the
`highly energized target plate through this path. Power is
`provided to the target plate through a power connection
`opening. In one configuration, a safety power connector
`fitting connects electrical power to the target plate only when
`a vacuum is pulled in the top chamber. The top chamber
`vacuum urges the safety connector to overcome an elastic
`barrier to make a tight electrical connection with the target
`backing plate.
`A power connection for the target plate also contributes to
`the safety of the processing operation. An insulated power
`connector is attached to a hole in the cover plate. At ambient
`conditions a gap between the energized conductors and outer
`surfaces of the conductor insulates operators from the ener­
`gized portion of the connector. However when the top
`chamber with the power connector in place is depressurized
`by pulling a vacuum, the elastic force separating the ener­
`gized pieces from the connection to the target contacts is
`overcome creating a good connection.
`In the configuration as described, very large substrates to
`be coated can be deposited from targets having sizes sub­
`stantially equal to the size of the substrates. For instance,
`large glass panel displays as might be used for large tele-
`vision-like screens whose dimensions are as much as two or
`three feet in any direction could be deposited from the
`sputtering target and sputtering chambers as described
`herein. Further, when conventional movable magnets are
`used behind the target assembly in a sweep pattern that
`erodes the target irregularly, the pressures in the two cham­
`bers may be adjusted to control the bow in the target
`assembly, thereby mechanically adjusting the distance
`
`

`

`Case 6:20-cv-00636-ADA Document 48-12 Filed 02/16/21 Page 25 of 30
`
`5,603,816
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`8
`FIG. 4 is bottom view of a target assembly with screw
`holes around the cooling passage inlet and outlet openings
`according to the invention;
`FIG. 4A is bottom view of a target assembly where the
`cooling passage inlet and outlet openings are threaded and
`configured to receive Cooling fluid hose fittings according to
`the invention;
`is a cross-sectional view of FIG. 4 taken at 5—5;
`FIG. 5
`is a cross-sectional view of FIG. 4 taken at 6—6;
`FIG. 6
`FIG. 7A is a bottom view of a cooling cover plate having
`generally equal sized cooling grooves according to the
`invention;
`FIG. 7B is a bottom view of a cooling cover plate having
`cooling grooves with unequal dimensions and spacing
`according to the invention;
`FIG. 7C is a bottom view of a cooling cover plate having
`mechanical fastening aids according to the invention;
`FIG. 8A shows a cross-section of FIG. 7A cut at 8A—8A
`and a cross-section of a bonding adhesive attached to a mesh
`for bonding the cover plate to a target backing plate accord­
`ing to the invention;
`FIG. 8B shows a cross-section of FIG. 7B cut at 8B—8B
`and a cross-section of a bonding adhesive attached to a mesh
`for bonding the cover plate to a target backing plate accord­
`ing to the invention;
`FIG. 8C shows a cross-section of FIG. 7C cut at 8C—8C
`and a cross-section of a bonding adhesive attached to a mesh
`for bonding the cover plate to a target backing plate accord­
`ing to the invention;
`FIG. 9 is a cross-sectional view of a sputtering device
`according to the invention showing a target assembly having
`a cooling cover plate with grooves therein according to the
`invention;
`FIG. 9A is a cross sectional detail view of the rough
`vacuum passage connection to the intermediate seal space
`around