U.S. patent application number 09/781981 was filed with the patent office on 2002-03-28 for vacuum treatment system for application of thin, hard layers.
Invention is credited to Hoffmann, Josef, Michael, Klaus, Rick, Alfred.
Application Number | 20020037368 09/781981 |
Document ID | / |
Family ID | 7866545 |
Filed Date | 2002-03-28 |
United States Patent
Application |
20020037368 |
Kind Code |
A1 |
Rick, Alfred ; et
al. |
March 28, 2002 |
Vacuum treatment system for application of thin, hard layers
Abstract
Vacuum treatment system for application of thin layers onto
substrates (36, 38, 40, 42) with a transfer chamber (5) and several
treatment chambers (6, 8, 10, 12), said treatment chambers
peripherally attached to the transfer chamber and being connected
to said transfer chamber by means of a common opening (27, 29, 31,
33) for inlet and outlet of substrate (36, 38, 40, 42), and with a
handling device (24) for transport of the substrate (36, 38, 40,
42) between the treatment chambers (6, 8, 10, 12), whereby the
handling device (24) has at least one substrate holder (37, 39, 41,
43) with one pivot and/or rotating retaining part to hold the
substrates (36, 38, 40, 42), by means of which the substrates (36,
38, 40, 42) can pivot and/or rotate in the treatment chambers (6,
8, 10, 12).
Inventors: |
Rick, Alfred; (Karlstein,
DE) ; Hoffmann, Josef; (Worth, DE) ; Michael,
Klaus; (Gelnhausen, DE) |
Correspondence
Address: |
SMITH GAMBRELL & RUSSELL, L.L.P.
Suite 800
1850 M Street, N.W.
Washington
DC
20036
US
|
Family ID: |
7866545 |
Appl. No.: |
09/781981 |
Filed: |
February 14, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09781981 |
Feb 14, 2001 |
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09302491 |
Apr 30, 1999 |
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6206975 |
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Current U.S.
Class: |
427/314 ;
427/248.1; 427/294; 427/596 |
Current CPC
Class: |
C23C 14/56 20130101 |
Class at
Publication: |
427/314 ;
427/294; 427/248.1; 427/596 |
International
Class: |
C23C 016/00; B05D
003/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 2, 1998 |
DE |
198 19 726.8 |
Claims
We claim:
1. A vacuum treatment system for deposition of a thin layer onto a
substrate comprising a transfer chamber, at least one treatment
chamber, said treatment chamber being peripherally attached to the
transfer chamber and being connected to said transfer chamber by
means of a common opening for inlet and outlet of said substrate, a
handling device for transport of the substrate having at least one
substrate holder with one pivot and/or rotating retaining part to
hold the substrate, whereby the substrate can be pivoted and/or
rotated in the treatment chamber.
2. The vacuum treatment system according to claim 1, wherein said
at least one treatment chamber has an outlet opening which can be
closed by a lid, and the substrate can move through the outlet
opening into and/or out of the vacuum treatment system.
3. The vacuum treatment system according to claim 1, wherein said
at least one treatment chamber has a heater so that the substrates
can be heated.
4. The vacuum treatment system according to claim 1, wherein said
at least one treatment chamber has a vacuum coating device, which
is used to coat the substrate with a material for vapor
coating.
5. The vacuum treatment system according to claim 4 wherein said
vacuum coating device is a vacuum vapor coating device.
6. The vacuum treatment system according to claim 5, wherein a
material to be vapor coated consists of a base alloy of the
composition MCrAlY, where the base alloy constituent M contains at
least one member selected from the group consisting of nickel,
cobalt, iron, and alloys thereof.
7. A method for the production of a wear-resistant, hard layer on a
substrate by means a vacuum treatment system comprising: a)
inserting a substrate to be coated into a first treatment chamber
through an outer opening therein and positioning of the substrate
on a substrate holder extending into said first treatment chamber;
b) evacuating said first treatment chamber for production of a
pressure equilibration between a transfer chamber having vacuum
pressure, and said first treatment chamber; c) moving the substrate
with a cover plate from a closed position assigned to the first
treatment chamber into a first assigned open-position by actuation
of a handling device; d) moving the substrate with the cover plate
from the first open-position into a second open position assigned
to a second treatment chamber, by a rotation of a handling device
by a rotational angle of 180.degree.; e) moving the substrate with
the assigned cover plate from the second open-position into a
second assigned closed position, so that the substrate is
transported into a second treatment chamber; f) heating the
substrate by means of heat energy in said second treatment chamber
to a temperature of>800.degree. C.; g) moving the heated
substrate from the second treatment chamber together with its
assigned cover plate into the second open-position; h) transporting
the substrate by rotation of the handling device about a rotational
angle of 90.degree. into a third open-position assigned to a third
treatment chamber; i) transporting of the substrate with its
assigned cover plate from said third open-position into a third
assigned closed position, so that the substrate is transported into
the third treatment chamber; j) coating the substrate with a
material cloud produced by vaporization of a coating source; k)
transporting the coated substrate with its assigned cover plate
into the third open-position; l) transporting the coated substrate
with its assigned cover plate by rotation of the handling device
about a rotational angle of 90.degree. into the first
open-position; m) transporting the coated substrate with its
assigned cover plate into the first closed position of the first
treatment chamber;
8. The method according to claim 7 further comprising ventilating
the first treatment chamber and removing the coated substrate
through the outlet opening of the first treatment chamber.
9. The method according to claim 7 wherein the temperature in (f)
is>1000.degree. C.
10. The method according to claim 7 wherein coating (j) is carried
out by electron beam vaporization.
11. The method according to claim 5 wherein said second treatment
chamber has a heater.
12. The method according to claim 5 wherein said third treatment
chamber has a vacuum coating source.
13. The method according to claim 7 wherein said substrate is a
workpiece intended for use in a turbine system.
14. The method according to claim 13 wherein the worpiece is a
turbine blade.
15. The method according to 14 wherein said turbine blade is for a
gas turbine engine.
Description
INTRODUCTION AND BACKGROUND
[0001] The present invention pertains to a vacuum treatment system
to be used to apply thin, hard layers to substrates. A vacuum
treatment system of this kind is composed of a transfer chamber and
several treatment chambers allocated to it, such that the
substrates to be coated can be inserted into or removed from the
treatment chambers by means of a handling device located in the
transfer chamber.
[0002] For coating of substrates by a coating method proceeding
under low-pressure conditions, differing types of systems are known
which are designed in accordance with the required treatment
stations for the substrates. Depending on the desired coating
method, e.g., a sputtering method or a vapor-coating method, and
depending on the coating system to be applied onto the substrate,
differing types of vacuum treatment systems are used. For example,
coating systems consisting of several single layers are produced on
the substrate by passing the substrate in sequence through
individual coating stations, where in each coating station, a
specific, single layer is deposited onto the substrate. Additional
treatment stations are needed when the substrate is additionally to
be subjected to heat treatment, or if the substrate surface is to
be subjected to a preceding or subsequent plasma etching process.
The configuration of the single treatment stations is established
in a known manner either in cluster formation or as an inline
system. When using the so-called inline system, the single
treatment stations are arranged one behind the other and the
substrate is transported successively through these treatment
stations to implement the individual treatment steps. These systems
have the advantage that they can be easily integrated into the
overall process, either upstream or downstream from the vacuum
treatment.
[0003] In the known cluster systems, the individual treatment
chambers are positioned essentially peripherally to the central
handling chamber in which a handling device is provided, by means
of which the substrates are transported between the individual
treatment chambers.
[0004] The essential advantage of cluster systems consists in the
fact that they are of compact, space-saving design. One
disadvantage of these cluster vacuum treatment systems is that the
substrates to be treated can only be operated in a so-called batch
mode. A continuous operation, like that possible in inline vacuum
treatment systems, is usually not possible for cluster systems. For
example, in the cluster system, a minimum number of treated
substrates is enclosed in one of the treatment stations and after
completed processing, all substrates are transported together from
the cluster vacuum system.
[0005] An object of the present invention is to create a vacuum
treatment system by means of which it is possible to process
substrates by vacuum processes, where the process sequence can be
integrated advantageously into existing production lines and a
space-saving design will be obtained.
[0006] Another object of the present invention is to provide a
method for coating of workpieces in this vacuum treatment
system.
SUMMARY OF THE INVENTION
[0007] The above and other object of this invention can be achieved
with a vacuum treatment system as described herein.
[0008] The vacuum treatment system according to this invention
consists essentially of a transfer chamber and of several treatment
chambers positioned peripherally to the transfer chamber and
connected with it by means of common openings for inlet and outlet
of the substrate. In the transfer chamber there is a handling
device with which the substrates can be transported between the
treatment chambers. In this regard, the handling device consists of
at least one substrate holder by means of which the substrates to
be transported are held. A smooth handling of the substrates within
the individual treatment chambers will be ensured in that the
substrate holder has a pivoting and/or rotating retaining unit, to
which the substrate is attached, and with which the substrate
located in the particular treatment chamber can pivot and/or rotate
during the processing.
[0009] In addition, the invented vacuum treatment system consists
of a treatment chamber which has an outer opening that can be
closed by a cover. The substrates to be coated are moved into the
vacuum treatment system and the coated substrates are removed from
the system through this outlet opening. The advantage achieved with
the invention consists, in particular, in that the vacuum treatment
system can be filled continuously with the substrates to be coated
and these can then be subjected to the vacuum treatment process in
order then to remove them continuously from the system. At the same
time, the vacuum treatment system according to this invention makes
possible a compact design which enables integration into existing
manufacturing systems.
[0010] In addition, due to the mounting of the substrates to be
coated to a pivoting and/or rotating retaining unit, it is assured
that the substrates in the individual treatment chambers are
exposed uniformly to the treatment processes acting on the
substrates. This will prevent the coatings to be deposited onto the
substrate to be coated, from growing at different rates at
different locations of the substrate surface due to their differing
alignment to the coating source. Thus, the layer thickness will not
be dependent on the substrate shape.
[0011] For coating of substrates, it is proposed to provide a
vacuum coating device, preferably a vacuum vapor coating device, in
at least one of the treatment chambers. For coating of a substrate,
the material to be vaporized and deposited is melted or vaporized
by heating in the vacuum vapor coating device and the substrate is
placed into the material cloud for precipitation of the vaporized
material onto the substrate surface.
[0012] The vacuum treatment system of the present invention is
suitable for uniform depositing of hard, thin layers onto
workpieces by means of a vacuum vapor coating method. In this
regard, the workpieces to be coated are initially heated in a first
treatment chamber in which a heater is located, to a sufficiently
high temperature, preferably>800.degree. C., and in the heated
state they are moved by means of the handling device into a second
treatment chamber containing the vapor coating device.
[0013] The hard, thin layers, for example, consist of metallic
alloys of the MCrAlY type, where the alloy component M, consists at
least of one of the substances nickel, cobalt or iron, or an alloy
containing a percentage of the substances nickel, cobalt or iron.
For melting of the vapor coating material, which consists of a base
alloy of the composition stated above, the use of a known electron
beam vaporizing source is suggested. In this case, the vapor
coating source will supply the molten material from a reservoir
preferably in rod shape.
BRIEF DESCRIPTION OF DRAWINGS
[0014] The present invention will be further understood with
reference to the accompanying drawings, wherein:
[0015] FIG. 1 represents a vacuum treatment system according to
this invention, shown in a top, sectional view;
[0016] FIG. 2 represents a cross sectional view of the vacuum
treatment system illustrated in FIG. 1, presented along the section
line B-B';
[0017] FIG. 3 represents a cross sectional view of the vacuum
treatment system illustrated in FIG. 1, presented along the section
line A-A'; and
[0018] FIG. 4 represents a partial sectional side view of the
vacuum treatment system illustrated in FIG. 1, presented along the
section line E-E'.
DETAILED DESCRIPTION OF INVENTION
[0019] A vacuum treatment system according to this invention is
suitable in a favorable manner for the manufacture of hard coatings
on those workpieces which are intended for use in turbine systems.
In particular, with this vacuum treatment system, hard,
corrosion-resistant metallic and/or ceramic thermal insulating
layers can be produced on turbine blades, preferably on turbine
blades for use in gas turbine engines. However, in principle,
application of the turbine blades coated by use of the invented
vacuum treatment system is not limited to the gas turbine
engine.
[0020] A method according to this invention for the manufacture of
wear-resistant, hard coatings on substrates by means of the
invented vacuum treatment system is composed of several process
steps which will be discussed below.
[0021] First, the substrate to be coated is moved from the outside
space into a first treatment chamber which has an outer opening,
and the substrate is attached to the substrate holder protruding
into this treatment chamber. The inner opening of the loading
chamber located opposite the outer opening is sealed vacuum-tight
from the transfer chamber by a cover plate during the loading
process. Next, the load chamber is evacuated to adjust the pressure
to the vacuum pressure prevailing in the transfer chamber. To move
the substrate or substrates to be coated into a first treatment
chamber, by actuation of the handling device, the cover plate is
moved together with the substrates from the closed position into
the assigned open-position. In this case, the handling device has a
shaft or coil spindle seated in the vacuum chamber cover and/or in
the vacuum chamber base plate of the transfer chamber; upon
rotation of the operators allocated to the coil spindle, the cover
plates connected with these operators are moved from a radially
inner opening to a radial outer closed position, or from the closed
position to the open position. For example, the operators consist
of hoisting drivers or telescoping booms, which are articulated on
one end on a spindle nut running on the spindle, and on the other
end are connected to the cover plates. The cover plates have
substrate holders or graspers on their side surfaces facing the
treatment chambers.
[0022] By turning the handling device by a rotary angle of e.g.,
90.degree. or 180.degree., the substrate with the cover plate will
be moved from the open-position of the first treatment chamber,
into the open-position assigned to the second treatment chamber. By
operation of the spindle drive or shaft drive of the handling
device, the substrates are moved from this open-position into the
allocated closed position. There, the substrate or substrates are
placed into the second treatment chamber and by use of the sealing
plate simultaneously separated vacuum-tight from the transfer
chamber. For coating of substrates with hard, thin,
corrosion-resistant layers, the substrates must be heated during
the entire coating process to a minimum temperature. In this
regard, the first treatment chamber has a heating unit with which
the substrates are heated to the required process temperature of
e.g., at least 800.degree. C., preferably to at least 1000.degree.
C.
[0023] The heated substrate is moved by means of the handling
device from the second treatment chamber to a third treatment
chamber, in a manner analogous to the transport from the loading
chamber to the second treatment chamber. In this vacuum treatment
chamber, there is a vacuum coating source, preferably a
vaporization source, which is used to vapor coat the material onto
the substrate. The substrates are preferably rotating or pivoting
in the vapor cloud of coating material during the coating process
and the substrates are thus coated uniformly because the coating is
essentially independent of the spatial shape of the substrates.
[0024] To apply hard, thin coatings, it has proven to be
advantageous to heat the molten material by means of a known
electron beam vaporizer to the vapor coating temperature. While the
molten material for the vapor coating has a high melting
temperature, due to the electron beam arriving locally on the
molten material, the needed melting or vaporization temperature is
attained.
[0025] After ending the coating phase, the substrate is moved via
the assigned open-position of the third treatment chamber, through
subsequent rotation of the handling device about a rotary angle of
90.degree., for example, into the open-position of the neighboring
treatment chamber. The substrate is then moved from this
open-position into the allocated closed position of this treatment
chamber which has a closable outer opening, while the inside of the
treatment chamber is separated by the cover plate vacuum-tight from
the transfer chamber. After venting the first treatment chamber
designed as a loading or unloading chamber, the coated substrates
are removed through the outer opening of the loading/unloading
chamber, e.g., by means of a robot handling device.
[0026] The number of treatment chambers can be selected as a
function of the particular vacuum treatment process. Preferably the
treatment chambers are located equidistant from each other and
peripherally to the transfer chamber. To transport the substrates
by rotation of the handling device between neighboring
open-positions, an angle .alpha.=360.degree./n is transited, where
n corresponds to the number of treatment stations. In a vacuum
treatment system according to this invention, the treatment
chambers can also be set up at an unequal distance from each other,
so that different values for a are obtained for the transport angle
between two treatment chambers.
[0027] The vacuum treatment system according to this invention will
be explained in greater detail below based on one particularly
preferred design example which is illustrated in the attached
drawings.
[0028] In FIG. 1, a vacuum treatment system 2 is presented which
has a total of four treatment chambers 6, 8, 10, 12. These handling
chambers 6, 8, 10, 12 are positioned peripherally to a transfer
chamber 5, where the transfer chamber 5 has an octahedral cross
section; the single treatment chambers 6, 8, 10, 12 are flanged to
every other octahedral side.
[0029] The treatment chambers 6, 8, 10, 12 are each connected to
the interior of the transfer chamber 5 by means of inner openings
17, 19, 21, 23. The individual treatment chambers 6, 8, 10, 12
differ in their function for one complete treatment cycle as
follows:
[0030] treatment chamber 6 is used as loading and unloading chamber
for the substrates 36,
[0031] treatment chamber 12 is used for pretreatment and/or
post-treatment of the substrates 42, 42',
[0032] treatment chamber 10 is designed as a heating chamber in
which the substrates 40 can be heated to a predetermined
temperature, and
[0033] treatment chamber 8 is designed as a coating chamber in
which the substrates 38 are coated by the use of a coating source
65.
[0034] The individual treatment chambers 6, 8, 10, 12 and also the
transfer chamber 5 can be evacuated to vacuum pressure by means of
vacuum pumps 14, 16, 18. A handling device 24 is allocated
essentially centrally to the treatment chambers 6, 8, 10, 12 (see
FIG. 1) in the transfer chamber 5; this handling device is used for
the transport of the substrates 36, 38, 40, 42, 42' between the
treatment chambers 6, 8, 10, 12. The handling device 24 consists of
a rotary table 20, which is rotary seated on a rotary axis 22. The
rotary table 20 is driven by a motor 60 via a transmission 61 which
is linked via a rotary drive shaft 55 to the rotary table 20.
[0035] A total of four cover plates 26, 28, 30, 32 corresponding to
the number of treatment chambers 6, 8, 10, 12, are provided to the
rotary table 20. These cover plates 26, 28, 30, 32 are used to seal
the openings 17, 19, 21, 23 to the treatment chambers. In this
case, the cover plates 26, 28, 30, 32 are each applied to an
operator which is formed as push/pull struts 48a, b; 49a, b; 50a,
b; 51a, b.
[0036] The push/pull struts 48a, b; 49a, b; 50a, b; 51a, b are
articulated on one end to the rotary table 20 and permanently hold
their connected cover plates 26, 28, 30, 32 in a perpendicular
alignment. To close the treatment chamber openings 17, 19, 21, 23,
the cover plates 26, 28, 30, 32 are moved from a radially inward,
open-position 26', 28', 30', 32' to a radially outer closed
position, and the operators cooperating directly with the drive
shaft 57 or cooperating with it by means of a coil spindle, are
designed as hoisting drive or telescoping boom.
[0037] The cover plates 26, 28, 30, 32 each have on their side
surfaces facing the treatment chambers 6, 8, 10, 12, substrate
holders or graspers with which the substrates 36, 38, 40, 42, 42'
are securely held and transported. The substrate holders 37, 39,
41, 43 are pivot mounted to the single cover plates 26, 28, 30, 32.
By means of a drive mechanism not illustrated in the figures, the
substrates 36, 38, 40, 42, 42' can pivot or rotate in the treatment
chambers 8, 10, 12, in particular during the single treatment
processes (see FIG. 2, FIG. 3). Due to this measure, the effect of
heat, for example, or of coating material to be deposited onto the
substrates 36, 38, 40, 42, 42', occurs uniformly over their entire
surface, even on substrates 36, 38, 40, 42 having irregular
surfaces.
[0038] For vacuum coating of a part of a substrate, this part will
be attached individually or together with other substrate parts, to
the substrate holder 37 protruding into the loading or unloading
chamber 6. After closing the cover 9, the loading or unloading
chamber 6 is evacuated to the pressure prevailing in the transfer
chamber 5. By operating of the handling device 24, the substrate 36
and the cover plate 26 are first moved into the assigned,
open-position 26'. Synchronously with this, the other substrates
38, 40, 42 are moved together with their associated cover plates
28, 30, 32 from the particular closed position, into the
open-positions 28', 30', 32' allocated to the treatment chambers 8,
10, 12.
[0039] For subsequent transport of the substrates 36, 38, 40, 42
into the next treatment chamber, the transport drive 54 (see FIG.
2) is activated and the rotary table 20 is moved together with the
handling device 24 and the substrates 36, 38, 40, 42 in the
transport direction D.
[0040] For coating of substrates with hard, thin layers which are
applied by vapor coating, it is necessary to hold the substrates
during the entire coating process to a temperature
of>800.degree. C., preferably>1000.degree. C. To do this, the
substrate to be heated is first moved from the loading/unloading
chamber 6 through a 180.degree. rotation with respect to the
heating chamber 10, and from the open position 30' by operation of
the spindle drive 56 into the allocated closed position.
[0041] With the heater 11 provided in the heating chamber 10, the
substrate 40 is heated under simultaneous rotation in the direction
R uniformly to the preselected temperature. After completion of the
warm-up phase, the substrate 40 is moved radially into the open
position 30', and by a 90.degree. rotation of the rotary table 20
about the rotary axis 22 and a radial transport motion, it is moved
into the coating chamber 8. In the coating chamber 8 the substrate
38 is then moved into a material cloud W, which is created, for
example, by means of a conventional vaporization source 65, for
precipitation of the vaporized molten material 66 on the substrate
38.
[0042] In order to obtain a uniform, homogeneous coating of the
substrate 38 independently of the precipitation site on the
substrate 38, the substrate 38 rotates about the axis of the
substrate holder 39 in the rotary direction R (see FIG. 4). The
coating source 65 pertains to an electron beam vaporization source
which is composed of a conventional electron beam gun 44 and the
vaporizer 65. The molten material 66 to be vaporized is moved from
a molten material reservoir 68 (see FIG. 4) to the vaporizer 65 in
rod form.
[0043] The electron beam EB emitted from the electron beam gun 44
is fired with an energy of 35 keV, for example, against the free
front surface of the melt material rod 66 protruding from the
vaporizer 65 and is directed through a magnetic field generated by
a coil (not illustrated in the figures). The molten material 66
melts at the impact point of the electron beam EB and vaporizes to
form a material cloud W which is precipitated upon the substrate
surface of the substrate 38.
[0044] After completion of the coating phase for the substrate 38,
the substrate will be transported either through another 90.degree.
transport cycle to the loading/unloading chamber 6 for ejection
from the vacuum treatment system 2, or will be post-treated in the
treatment chamber 12. As post-treatment process, a subsequent
oxidation of the coated substrate surface can take place by inlet
of a reactive oxidizing gas, or the substrate can also be exposed
to another heat treatment.
[0045] Further variations and modifications of the foregoing will
be apparent to those skilled in the art and are intended to be
encompassed by the claims appended hereto.
[0046] German priority application 198 19 726.8 is relied on and
incorporated herein by reference.
* * * * *