Page 1 of 16
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`Samsung Exhibit 1017
`Samsung Electronics Co., Ltd. v. Daniel L. Flamm
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`

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`5,883,778
`Page 2
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`US, PATENT DOCUMENTS
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`‘
`1/1993 1“1“g119S~
`5.-181559
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`4/1993 Ha111bu1'ge11 et al.
`5,203,401
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`5/1993 Barnes eta1..
`5,207,437
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`7/1993 Van de V611 et al.
`5,230 741
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`5,252,132 10/1993 Oda etal..
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`5,252,850 10,1995 schempp.
`10/1993 Nozawa et al.
`5,255,153
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`.
`5,270,266
`12/1993 Hiram) el al.
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`5,275,683
`1/1994 Ammi et al. N
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`5,280,156
`1/1994 Niori ct a1.
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`5,287,914
`2/1994 I-Iughes ,
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`4/1994 Ivlaeda et al.
`5,302,209
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`5,303,938
`4/1994 Ivliller et al.
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`5/1994 Fschbach .
`5,312,509
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`361/234
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`279/128
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`5,315,473
`5/1994 Collins et al.
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`5,345,999
`9/1994 Hosokawa
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`5350 479
`9/1994 Collins et a1.
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`595569476
`10,1994 Foster et al
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`6/1995 T0m1ta et al.
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`5,423,936
`156/345
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`9/1995 Barnes et 8.1.
`3,452,510
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`7/1996 Nozawa 01 6.1.
`5,539,179
`219/121.43
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`7/1996 Collins et a1-
`361/234
`5,539,609
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`8/1996 Kawakami et al.
`5,542,559
`216/67
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`6/1997 Sherstinsky el al.
`. 361/234
`5,634,266
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`........ ..
`8/1997 Burkhart et £11.
`5,656,093
`279/128
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`9/1997 Sherstinsky et a1.
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`Page 2 of 16
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`U.S. Patent
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`Mar. 16, 1999
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`Sheet 1 of 6
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`U.S. Patent
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`Mar. 16, 1999
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`U.S. Patent
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`Mar. 16, 1999
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`U.S. Patent
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`U.S. Patent
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`Mar. 16, 1999
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`U.S. Patent
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`Page 8 of 16
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`5,883,778
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`1
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`ELECTROSTATIC CHUCK WITH FLUID
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`FLOW REGULATOR
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`CROSS-RJ:'FERl:'N CE
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`This application is a continuation—in—part of U.S. patent
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`application Ser. No. 08/203,111, entitled “Electrostatic
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`Chuck,” filed on Feb. 28, 1994 now abandoned; and is
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`related to U.S. Pat. No. 5,634,266, patent application Ser.
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`No. 08/449,135, filed on May 24, 1995, both of which are
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`incorporated herein by reference.
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`BACKGROUND
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`The present invention is directed to an electrostatic chuck
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`for holding, and maintaining substantially uniform ten1pera-
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`tures across a substrate during processing of the substrate,
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`and for increasing the life of the chuck in erosive process
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`environments.
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`In semiconductor fabrication processes, electrostatic
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`chucks are used to hold substrates for processing of the
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`substrate. Electrostatic chucks are particularly useful
`in
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`vacuum processing environments where there is insuflicient
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`differential pressure to hold the substrate using a vacuum
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`chuck. A typical electrostatic chuck comprises an electro-
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`static member supported by a support adapted to be secured
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`in a process chamber. The electrostatic member comprises
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`an electrically insulated electrode. An electrical connector
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`electrically connects the electrode to a voltage supply source
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`in the process chamber. When the electrode is electrically
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`biased with respect
`to the substrate held on the chuck,
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`opposing electrostatic charge accumulates in the electrode
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`and substrate, resulting in attractive electrostatic forces that
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`hold the substrate to the chuck. Electrostatic chucks are
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`generally described in, for example U.S. patent application
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`Ser. Nos. 08/278,787 by Cameron, et al.; 08/276,735 by
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`Shamouilian, et al.; and 08/189,562, by Shamouilian, et
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`al.—all of which are incorporated herein by reference.
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`Conventional electrostatic chucks can also have tempera-
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`ture controlling systems to regulate the temperatures across
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`the substrate held on the chuck. However, conventional
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`temperature controlling systems often do not maintain uni-
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`form temperatures across the substrate, particularly at the
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`perimeter or edge of the substrate. Excessively high tem-
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`peratures at portions of the substrate can damage the inte-
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`grated circuit chips formed on the substrate, and low tem-
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`peratures can result
`in non—uniform processing of the
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`substrate.
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`A typical conventional
`temperature controlling system
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`functions by introducing a heat
`transfer fluid, such as
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`helium, below the substrate via a single central aperture in _
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`the chuck. The single central aperture is often used to supply
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`helium to recessed cavities below the substrate, such as an
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`open trough or pattern of interconnected grooves, to distrib-
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`ute helium below the substrate. The trough or patterned
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`grooves often stop short of the perimeter of the chuck
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`forming a relatively large edge gap between the trough
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`edges, or groove tips, and the perimeter of the substrate held
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`on the electrostatic member, the gap often exceeding 10 to
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`20 mm. The large edge gap is provided to allow the
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`overlying perimeter of the substrate to cover and seal the
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`trough or grooves so that the heat transfer fluid does not leak
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`out into the process environment. However, because no heat
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`transfer fluid is held below the perimeter of the substrate
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`overlying the edge gap, the temperature of the substrate
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`perimeter is controlled less effectively compared to central
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`portions of the substrate, resulting in non—uniform tempera-
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`tures across the substrate.
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`Conversely, extending the edges of the trough or tips of
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`the grooves all the way to the perimeter of the chuck causes
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`other problems. The small gap between the trough edges, or
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`groove tips, and the overlying substrate perimeter, can result
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`in excessive leakage of helium at portions of the trough
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`edges or groove tips. The accompanying reduction in tem-
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`perature control of the overlying portions of the substrate
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`perimeter, causes the substrate to exhibit hot or cold spots,
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`and results in reduced yields of integrated circuits formed on
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`the substrate.
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`Another limitation of conventional chucks results from
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`the structure of the electrostatic member 10 of the chuck 11,
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`which typically comprises a copper electrode layer 12
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`sandwiched between two polymer insulator layers 13a, 13b
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`as shown in FIG. 1. The polymer layers 1311, 13b overlap
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`beyond the edge of the copper electrode 12 at an outer
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`periphery 14 of the electrostatic member to electrically
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`insulate and seal the electrode 12. Typically, the overlapping
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`portions of the polymer layers form a lower annular step 15
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`of approximately 0.5 to 2 mm, and more typically 1.25 to
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`1.50 mm width around the circumference of the raised
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`electrode 12. The annular step 15 has several detrimental
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`effects on the electrostatic chuck 11. First, because of the
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`annular step 15, only a small portion of the outer periphery
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`14 of the electrostatic member 10 contacts the perimeter 16
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`of the substrate 17 beyond the circumference of the elec-
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`trode 12. As a result, there is an increased probability of
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`helium leakage from groove tips 18 near the outer periphery
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`14 contributing to excessive overheating of the substrate 17.
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`A second effect is that the relatively small width of polymer
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`insulator 10 separating the circumference of the electrode 12
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`from the process environment can cause a higher failure rate
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`of the chuck 11, because the small insulator portion 19 can
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`be rapidly eroded by the erosive process environment,
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`exposing the electrode 12 and causing short—circuiting of the
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`chuck 11. Erosion of insulator portion 19 is particularly
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`rapid in oxygen or halogen containing gases and plasmas,
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`which are used for a variety of tasks, such as for example,
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`etching of substrates and cleaning of process chambers.
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`Failure of the chuck during processing of the substrate can
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`damage the substrate, and necessitates frequent replacement
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`of short-circuited chucks.
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`Thus, it is desirable to have an electrostatic chuck having
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`a temperature controlling system that allows maintaining
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`substantially uniform temperatures across the substrate, and
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`in particular the perimeter of the substrate, to provide higher
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`integrated circuit chip yields from the substrate. It is also
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`desirable to have an electrostatic chuck which demonstrates
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`improved erosion resistance, and reduced failure rates, in
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`erosive process environments.
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`SUMMARY
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`invention provides an electrostatic chuck
`The present
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`capable of maintaining substantially uniform temperatures
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`across a substrate and having improved erosion resistant in
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`an erosive process environment. One version of the electro-
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`static chuck comprises an electrostatic member that includes
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`(i) an insulator covering an electrode, (ii) a substantially
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`planar and conformal contact surface capable of conforming
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`to the substrate, and (iii) conduits terminating at the contact
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`surface for providing heat
`transfer fluid to the contact
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`surface. Application of a voltage to the electrode of the
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`electrostatic member electrostatically holds the substrate on
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`the conformal contact surface to define an outer periphery
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`having (1) leaking portions where heat transfer fluid leaks
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`out, and (2) sealed portions where heat transfer fluid sub-
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`stantially does not leak out. A fluid flow regulator is pro-
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`Page 9 of 16
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`5,883,778
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`3
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`vided for flowing heat transfer fluid at different flow rates
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`through the conduits in the electrostatic member to provide
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`(i) first flow rates of heat transfer fluid through the conduits
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`adjacent to the sealed portions of the outer periphery of the
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`electrostatic member, and (ii) second flow rates of heat
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`transfer fluid through the conduits adjacent to the leaking
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`portions, the second flow rates being higher than the first
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`flow rates, to maintain substantially uniform temperatures
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`across the substrate held on the chuck.
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`Preferably, the fluid flow regulator includes a heat transfer
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`fluid reservoir having at least one of the following charac-
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`teristics
`the reservoir is positioned proximate to the
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`electrostatic member, (ii) the reservoir extends across all the
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`conduits, and (iii) the reservoir is sized and configured to
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`hold a suflicient volume of heat transfer fluid at a sufliciently
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`elevated pressure relative to the pressure in the process
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`chamber,
`to provide the second higher flow rates of heat
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`transfer fluid to the conduits adjacent to the leaking portions
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`of the outer periphery of the electrostatic member.
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`Preferably,
`the heat
`transfer fluid reservoir is sized and
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`configured to hold heat transfer fluid at a pressure P in the
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`range of from about PL to about PH,
`the pressure PHbeing
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`sufficiently low that flow of heat transfer fluid through the
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`conduits does not dislodge the electrostatically held
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`substrate, and (ii) the pressure PL being sufliciently high to
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`provide the second higher [low rates of heat transfer fluid to
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`the conduits adjacent to the leaking portions of the outer
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`periphery substantially without reducing the first lower flow
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`rates of heat transfer fluid to the conduits adjacent to the
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`sealed portions.
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`In another version useful for maintaining uniform tem-
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`peratures across the substrate held on the chuck, the elec-
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`trostatic chuck comprises a support with an electrostatic
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`member thereon. The electrostatic member comprises an
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`insulated electrode laminate capable of holding a substrate
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`upon application of a voltage to tl1e electrode. Aplurality of
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`conduits extend through the support and the electrostatic
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`member for providing heat transfer fluid below the substrate,
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`at least some of the conduits terminating near an outer
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`periphery of the electrostatic member. The multiple conduits
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`at the outer periphery of the electrostatic member distribute
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`heat transfer fluid at multiple sources below the perimeter of
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`the substrate improving temperature control of the substrate.
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`Another version of the electrostatic chuck is substantially
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`erosion resistant and is useful for holding a substrate in an ’
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`erosive process environment.
`In this version,
`the chuck
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`comprises a support with an electrostatic member thereon.
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`The electrostatic member comprises a laminate including
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`a first insulator layer,
`an electrode on the first insulator
`layer, and (iii) a second insulator layer over the electrode and
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`merging with the first insulator layer around the circumfer-
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`ence of the electrode to electrically insulate the electrode.
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`The laminate has a contact surface for contacting the sub-
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`strate that is substantially planar over the entire width of the
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`electrostatic member so that when a substrate is electrostati-
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`cally held on the contact surface, the planar contact surface
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`provides continuous contact with the substrate to widely
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`separate the electrode from the erosive process environment,
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`providing enhanced erosion resistance. Preferably, the sup-
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`port includes an upper surface having a recess therein, and
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`the electrode on the first insulator layer is sized to substan-
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`tially fill the recess so that the laminate forms a substantially
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`planar contact surface.
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`DRAWINGS
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`These and other features, aspects, and advantages of the
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`present invention will become better understood with regard
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`4
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`to the following description, appended claims, and accom-
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`panying drawings which provide illustrative examples of the
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`invention, where:
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`FIG. 1 (Prior Art) is a partial cross—section side schematic
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`View of a prior art electrostatic chuck showing the annular
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`step around the electrode where the polymer insulator rap-
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`idly erodes in an erosive environment;
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`FIG. 2a is a partial cross—section side schematic View of
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`a process chamber showing operation of a monopolar elec-
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`trostatic chuck of the present invention,
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`FIG. 2b is a partial cross—section side schematic View of
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`a process chamber showing operation of a bipolar electro-
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`static chuck of the present invention;
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`FIG. 3a is a cross—section side schematic view of a version
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`of the chuck comprising a fluid flow regulator in the support;
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`FIG. 3b is a top view of the chuck shown in FIG. 3:1;
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`FIG. 4a is a partial cross—section side schematic View of
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`another version of the chuck of the present invention;
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`FIG. 4b is a top view of the chuck shown in FIG. 4a;
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`FIG. 5a is a partial cross—section side schematic view of
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`another version of the chuck of the present invention;
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`FIG. 5b is a top View of the chuck shown in FIG. 5a, and
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`FIG. 6 is a partial cross—section side schematic view of an
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`erosion resistant chuck of the present invention.
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`DESCRlP'l'l()N
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`With reference to FIGS. 2a and 2b, operation of an
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`electrostatic chuck 20 of the present invention in a process
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`chamber 25 suitable for processing a substrate 30 will be
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`generally described. The particular embodiment of the pro-
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`cess chamber 25 shown herein is suitable for plasma pro-
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`cessing of substrates 30 and is provided only to illustrate
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`operation of the chuck 20 and should not be used to limit the
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`scope of the invention.
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`the electrostatic chuck 20
`With reference to FIG. 2a,
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`comprises an electrostatic member 35 having
`a single
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`electrode 40 with an insulator 45 covering the electrode 40,
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`and (ii) a substantially planar and conformal contact surface
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`50 capable of conforming to a substrate 30. An electrical
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`connector 55 connects the electrode 40 to a voltage supply
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`terminal 60 in the chamber 25, to conduct a voltage suitable
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`for operating the chuck 20. A first voltage supply 65 con-
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`nected to the terminal 60 typically comprises a high voltage
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`DC source of about 1000 to 3000 volts, connected to a high
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`voltage readout through a 1 M9 resistor. A 1 M9 resistor is
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`provided in the circuit to limit the current flowing through
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`the circuit and a 500 pF capacitor is provided as an alter-
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`nating current filter.
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`Typically, the electrostatic member 35 is supported by a
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`support 70 that provides structural rigidity to the electro-
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`static member 35, and is designed to be secured to a process
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`electrode, commonly known as a cathode 80, in the process
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`chamber 25. Asecond voltage supply 90 is connected to the
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`cathode 80 in the process chamber 25. At least a portion of
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`the cathode 80 is electrically conductive,
`typically
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`aluminum, and functions as a negatively biased electrode
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`with respect to an electrically grounded surface 95 in the
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`chamber 25. The second voltage supply 90 is conventional
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`and electrically biases the cathode 80 by a circuit comprising
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`an RF impedance that matches the impedance of the process
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`chamber 25 to the impedance of the line voltage, in series
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`with an isolation capacitor, as shown in FIG. 251.
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`To operate the chuck 20,
`the process chamber 25 is
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`evacuated to a pressure ranging from about 1 to about 500
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`Page 10 of 16
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`

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`5,883,778
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`5
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`mTorr, and more typically from about 10 to about 100
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`mTorr. A semiconductor substrate 30, such as a silicon
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`is transferred to the chamber 25 from a load lock
`wafer,
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`transfer chamber (not shown), and placed on the conformal
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`contact surface 50 of the electrostatic member 35. Process
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`gas for etching or depositing material on the substrate 30 is
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`introduced in the chamber 25. Suitable process gases are
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`generally described in S. Wolf and R. N. Tauber, Silicon
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`Processing for the VLSI Era, Vol. I, Lattice Press, Sunset
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`Beach, Calif. (1986), which is incorporated herein by ref-
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`erence. A plasma is formed from the process gas by acti-
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`vating the second voltage supply 90 to electrically bias the
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`cathode S0 with respect to the grounded surface 95 of the
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`chamber 25.
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`The voltage applied to the mono polar electrode 40 causes
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`electrostatic charge to accumulate in the electrode 40, and
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`the plasma in the chamber 25 provides electrically charged
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`species having opposing polarity which accumulate in the
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`substrate 30. The accumulated opposing electrostatic charge
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`results in an attractive electrostatic force between the sub-
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`strate 30 and the electrode 40 in the chuck 20, causing the
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`substrate 30 to be electrostatically held to the chuck 20.
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`Instead of a single electrode 40, the electrostatic member
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`35 of the chuck 20 can comprise two bipolar electrodes 40a,
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`40b, as shown in FIG. 2b. The two bipolar electrodes 40a,
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`40b are typically coplanar to one another and have substan-
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`tially equivalent areas to generate equivalent electrostatic
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`forces. The first voltage supply 65 powering the bipolar
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`electrodes in the chuck 20 can have several alternative
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`configurations. In a preferred configuration, the first voltage
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`supply 65 comprises first and second voltage sources 65a,
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`65b, which provide negative and positive voltages to the first
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`and second electrodes 40a, 40b, respectively to maintain the
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`electrodes 40a, 40b at negative and positive electric poten-
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`tials. The opposing electric potentials induce opposing elec-
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`trostatic charges in the electrodes 4011, 40b and in the
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`substrate 30 held to the chuck 20, Without use of a plasma
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`in the process chamber 25, causing the substrate 30 to be
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`electrostatically held to the chuck 20. Bipolar electrode
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`configurations are advantageous for non-plasma processes
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`in which there are no charged plasma species to serve as
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`charge carriers for electrically biasing the substrate.
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`The chuck 20 further comprises a plurality of conduits
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`105 terminating at the contact surface 50 of the electrostatic
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`member 35 to provide heat transfer fluid, typically helium,
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`below the substrate 30 to maintain uniform temperatures
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`across the substrate 30. When the monopolar electrode 40,
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`or the bipolar electrodes 40a, 40b are activated to impart
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`opposing electrostatic charge to the substrate 30 and the
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`electrode 40, the substrate 30 is attracted toward and presses _
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`against the conformal contact surface 50 of the electrostatic
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`member 35. Typically, on a microscopic level, only a small
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`portion of the substrate 30 actually contacts the contact
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`surface 50. Heat transfer fluid below the substrate 30 flows
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`into the microscopic gap between the substrate 30 and the
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`contact surface 50, providing thermal coupling by gas con-
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`duction between the substrate 30 and the contact surface 50,
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`allowing enhanced thermal
`transfer between the non-
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`contacting portions of the substrate 30 and the contact
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`surface 50. The substrate 30 presses against the contact
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`leaking
`surface 50 to define an outer periphery 110 having
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`portions ll5 where heat
`transfer fluid leaks out
`to the
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`process environment 120 from between gaps 125 in the
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`outer periphery 110, and
`non-leaking or sealed portions
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`130 where there are substantially no gaps in the outer
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`periphery 110 and substantially no heat transfer fluid leaks
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`out.
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`8
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`6
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`The heat transfer fluid can be any liquid or gas capable of
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`transferring heat to the substrate 30, or removing heat from
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`the substrate 30. Preferably, the heat transfer fluid comprises
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`a non-reactive gas that is substantially non-reactive to the
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`process environment
`in the process chamber 25 so that
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`leaking heat
`transfer fluid does not adversely aifect
`the
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`processes performed on the substrate 30. The non-reactive
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`gas should also be non-reactive to the materials used to
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`fabricate the chuck 20, and in particular, to the conformal
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`contact surface 50 which is in contact with the non-reactive
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`gas.
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`For example, when polymeric materials such as polyim-
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`ide are used to fabricate the conformal Contact surface 50,
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`reactive gases that erode polyimide, such as
`oxygen, or
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`(ii) halogen—containing gases, such as CF4 or CZF6, should
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`be avoided. Preferably, the heat transfer fluid has an elevated
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`thermal conductivity to provide optimal thermal transfer
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`rates between the substrate 30 and the chuck 20. Preferred
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`transfer fluids that are non-reactive to the process
`heat
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`environment and conformal contact surface, and that have
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`elevated thermal conductivity comprise helium, argon,
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`nitrogen and the like. The thermal conductivity at about
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`room temperature of argon is about 43><1U‘6, nitrogen is
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`about 62><l0'6, and helium is about 360><10'5 in cal/(sec)
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`(cm2)(°C./cm). Thus, by elevated thermal conductivity, it is
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`meant a room temperature thermal conductivity of about 40
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`to about 360 cal/(sec)(cm2)(°C./cm).
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`The heat transfer fluid can be used to cool or heat the
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`substrate 30 to achieve uniform temperatures on the sub-
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`strate 30. When cooling of the substrate is needed, the chuck
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`20 is maintained at a lower temperature than the substrate
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`30, so that the heat transfer fluid can transfer heat from the
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`substrate 30 to the chuck 20. Alternatively, when the sub-
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`strate is to be heated, the chuck 20 is maintained at a higher
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`temperature than the substrate 30, so that the heat transfer
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`fluid can transfer heat from the chuck 20 to the substrate 30.
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`The electrostatic chuck 20 of the present invention pro-
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`vides improved temperature control of the substrate 30 by
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`use of a fluid flow regulator 135 capable of flowing heat
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`transfer fluid at different flow rates through the conduits 105
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`to offset leakage of he at transfer fluid from leaking portions
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`115 of the outer periphery 110 of the electrostatic member
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`35. This reduces the formation of “hot spots” or “cold spots”
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`on the portions of the substrate 30 overlying the leaking
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`portions 11 5, allowing maintaining the substrate 30 at
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`uniform temperatures. The fluid flow regulator 135 provides
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`(i) first lower volumetric flow rates of heat transfer fluid
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`through the conduits 105 adjacent to the sealed portions 130
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`of the outer periphery 110 of the electrostatic member 35,
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`and (ii) second higher volumetric flow rates of heat transfer
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`fluid through the conduits 105 adjacent
`to the leaking
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`portions 115, without reducing the flow rates of heat transfer
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`fluid to the non-leaking portions of the outer periphery 110.
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`Preferably, the second flow rates of heat transfer fluid to the
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`conduits 105 adjacent to the leaking portions 115 of the outer
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`periphery 110 are at least about 2 seem higher, and more
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`preferably at least about 5 sccm higher, than the first flow
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`rates of heat transfer fluid to the conduits 105 adjacent to the
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`sealed portions 130. Typically, the first flow rates range from
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`about 0 to about 1 sccm, and the second flow rates range
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`from about 1 seem to about 10 sccm.
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`Typical heat transfer fluid flow regulator structures 135
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`will now be described. One version of the fluid flow regu-
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`lator 135 includes a heat transfer fluid reservoir 140 formed
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`in the support 70 below the electrostatic member 35, the
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`length of the reservoir 140 extending across all of the
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`conduits 105 to provide a short flow path between the
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`Page 11 of 16
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`5,883,778
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`7
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`transfer fluid reservoir 140.
`conduits 105 and the heat
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`Multiple conduits 105, typically from about 50 to about 500
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`conduits, and more typically 100 to 200 conduits, extend
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`from the heat transfer fluid reservoir 140 to the contact
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`surface 50 of the electrostatic member 35. As shown in FIG.
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`3a, the conduits 105 include peripheral conduits 105a near
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`a perimeter 150 of the substrate 30, as well as central
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`conduits 105b at central portions 155 of the substrate 30.
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`Typically, the peripheral conduits 105a are located within
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`about 10 mm, and more preferably within 5 mm from the
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`perimeter 150 of the substrate 30. The peripheral conduits
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`105a and central conduits 105b are uniformly spaced apart
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`and distributed across substantially the entire Contact surface
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`50 to provide multiple sources of heat transfer fluid below
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`the substrate 30. The multiple sources of heat transfer fluid
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`allow the heat
`transfer fluid to be uniformly distributed
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`below th