U.S. patent application number 12/954053 was filed with the patent office on 2011-05-26 for method and device for the absorption of heat in a vacuum coating apparatus.
This patent application is currently assigned to VON ARDENNE ANLAGENTECHNIK GMBH. Invention is credited to Knut BARTHEL, Michael HENTSCHEL, Reinhard JAEGER, Marco KENNE, Steffen LESSMAN, Damir MUCHAMEDJAROW, Hubertus VON DER WAYDBRINK.
Application Number | 20110120682 12/954053 |
Document ID | / |
Family ID | 44061236 |
Filed Date | 2011-05-26 |
United States Patent
Application |
20110120682 |
Kind Code |
A1 |
VON DER WAYDBRINK; Hubertus ;
et al. |
May 26, 2011 |
METHOD AND DEVICE FOR THE ABSORPTION OF HEAT IN A VACUUM COATING
APPARATUS
Abstract
An apparatus and method for heat absorption in vacuum coating
installations includes an absorber having a line system to supply a
coolant. The line system is enclosed by a jacket tight relative to
the vacuum chamber, flow spaces are arranged between the line
system and the jacket, which are connected to a source of heat
exchanger medium so that the line system is flowed around by a heat
exchanger medium sealed relative to the vacuum chamber.
Inventors: |
VON DER WAYDBRINK; Hubertus;
(Dresden, DE) ; BARTHEL; Knut; (Dresden, DE)
; HENTSCHEL; Michael; (Dresden, DE) ; LESSMAN;
Steffen; (Dresden, DE) ; KENNE; Marco;
(Dresden, DE) ; MUCHAMEDJAROW; Damir; (Bannewitz,
DE) ; JAEGER; Reinhard; (Coswig, DE) |
Assignee: |
VON ARDENNE ANLAGENTECHNIK
GMBH
Dresden
DE
|
Family ID: |
44061236 |
Appl. No.: |
12/954053 |
Filed: |
November 24, 2010 |
Current U.S.
Class: |
165/154 |
Current CPC
Class: |
C23C 14/541 20130101;
F28D 15/00 20130101; F28D 7/12 20130101 |
Class at
Publication: |
165/154 |
International
Class: |
F28D 7/10 20060101
F28D007/10 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 25, 2009 |
DE |
10 2009 055 619.2 |
Mar 24, 2010 |
DE |
10 2010 003 215.8 |
Claims
1. Apparatus for heat absorption in vacuum coating installations
with an absorber, which has a line system for guiding of a coolant,
wherein the line system is enclosed by a jacket, tight relative to
a vacuum chamber, and flow spaces are arranged between the line
system and the jacket, the spaces being connected to a source of
the heat exchanger medium.
2. Apparatus according to claim 1, wherein the line system
comprises a closed outer tube having a coolant line arranged in an
internal space of the outer tube, and the outer tube is provided
with a jacket tube arranged spaced via a spacer to form a flow
space connected to the source of heat exchanger medium.
3. Apparatus according to claim 2, wherein an inner tube open to
the internal space is arranged in the outer tube and the inner tube
is connected to a vacuum source or sink and the internal space of
the outer tube is connected to a vacuum sink or vacuum source.
4. Apparatus according to claim 3, wherein the inner tube is
arranged concentrically in the outer tube.
5. Apparatus according to claim 2, wherein the jacket tube is
arranged concentric to the outer tube.
6. Apparatus according to claim 2, wherein an outside of the jacket
tube is provided with surface-enlarging elements.
7. Method for heat absorption in vacuum coating installations
comprising flowing a coolant through a line system to take off
absorbed heat, and flowing a heat exchanger medium sealed relative
to a vacuum chamber around the line system.
8. Method according to claim 7, wherein the coolant comprises
water.
9. Method according to claim 7, wherein the heat exchanger medium
comprises a gas.
10. Method according to claim 9, wherein the heat exchanger medium
contains helium.
11. Method according to claim 10, wherein the heat exchanger medium
consists of helium.
12. Method according to claim 9, wherein the heat exchanger medium
contains hydrogen.
13. Method according to claim 12, wherein the heat exchanger medium
consists of hydrogen.
14. Method according to claim 9, wherein the heat exchanger medium
contains air.
15. Method according to claim 14, wherein the heat exchanger medium
consists of air.
16. Method according to claim 7, wherein a temperature difference
between the coolant and the heat exchanger medium is controlled by
pressure, flow rate and/or gas composition.
Description
[0001] The invention concerns a device for heat absorption in
vacuum coating installations with an absorber, which has a line
system to supply a coolant, as well as a method for heat absorption
in vacuum coating installations in which a coolant is guided
through a line system and takes off absorbed heat.
[0002] For the application of layers on the substrates it is known
to carry out coating from the vapor phase or via sputtering with or
without chemical reaction with a reactive gas.
[0003] Especially during coating from the vapor phase the substrate
is not rarely exposed to a significant thermal load. The evaporator
source is heated to the evaporation temperature of the evaporation
material. The evaporator source then represents a significant heat
source.
[0004] In the production of photovoltaic layers a semiconducting
absorber layer is deposited by passing a precoated glass in a
transport direction through a metal evaporator source or past it,
which is thermally exposed to a temperature of more than
1200.degree. C. It is then the hazard that the substrate will be
overheated or will experience unduly high thermal gradients during
passage by the evaporator source in the transport direction.
[0005] For this reason there is a need for substrate cooling, which
can be achieved with radiation cooling, in which heat-absorbing
surfaces or elements are arranged in the radiation vicinity of the
substrate. It is also important to absorb radiation reflecting from
a substrate, which would lead to heating if not absorbed
("destroyed"). Three different cases can be distinguished here:
[0006] 1. The substrate has a high absorption capacity, for
example, E=1 on the top (on one side): The entire radiation power
coming from the evaporation source is then absorbed by the
substrate and leads to its heating. Depending on the temperature
level, the substrate has the capability of radiating heat by heat
radiation if surfaces, whose temperature lies below that of the
substrate, are situated in the vicinity of the radiating substrate
and these surfaces have absorption capacity. [0007] 2. The
substrate has a negligibly small absorption capacity: In this case
the substrate absorbs negligibly small amounts of the radiation
emitted from the evaporation source. Almost the entire radiation
impinging on the substrate is reflected. If the radiation so
reflected is not absorbed by the surroundings, the temperature of
the surroundings goes up and ultimately leads to heating of the
substrate, since now the temperature of the surroundings can be
very high and even small absorption capacity of the substrate can
lead to undesired heating of the substrate. [0008] 3. The substrate
has an average absorption capacity: This is close to the practical
case. Both removal of radiation from the substrate and removal of
reflected radiation make absorption necessary.
[0009] In some coating processes the condition must now be
maintained in which a minimum temperature must be set on the
surfaces in the process space in order to be able to set the vapor
pressure of low-melting materials sufficiently high. Condensation
of process materials can occur on colder surfaces. This leads to a
situation in which evaporated material is withdrawn from the
process, which is then no longer available for deposition to form
the desired stoichiometry or must be significantly replenished. A
significant loss of material occurs here, which should be
limited.
[0010] On the other hand, condensation leads to undesired
contaminants on these condensation surfaces, which is also
connected with bursting, which leads to contamination of the
layers.
[0011] Ordinarily water is used as cooling medium, which is fed in
closed line systems. The water-traversed line systems then
represent the absorbers within the vacuum chamber. However, the
condition of minimum temperature is violated in principle with such
a layout of an absorber.
[0012] Either such absorbers cannot be used and the risk of
substrate overheating must be tolerated or these absorbers are
simultaneously condensers for the vapor of the evaporator
source.
[0013] The task of the invention is therefore to provide a
radiation cooling system and method for radiation cooling of vacuum
coating processes with which effective cooling is achieved and
condensation is avoided.
[0014] The task is solved by an apparatus with the features of
Claim 1. Claims 2 to 6 represent favorable variants.
[0015] The task is also solved by a method with the features of
claim 7. Claims 8 to 16 provide a special embodiment of the method
according to the invention.
[0016] The invention will be further explained below with reference
to a practical example. In the accompanying drawings
[0017] FIG. 1 shows a schematic cross section through an absorber
according to the invention,
[0018] FIG. 2 shows a schematic depiction of the use of an absorber
according to the invention in a vacuum chamber and
[0019] FIG. 3 shows a schematic view of the use of an absorber
according to the invention on the evaporator side.
[0020] As shown in 16 the absorber 1 according to the invention has
an outer tube 2, which is introduced to a vacuum chamber 4
vacuum-tight through a chamber wall 3. The outer tube 2 is sealed
relative to the vacuum chamber.
[0021] An inner tube (6) is arranged in the internal space 5 of the
outer tube 2. The inner tube (6) is opened on one side to the
internal space 5. On its other side the inner tube (6) is connected
to a coolant source (not further shown), like the pressure side of
a pump. The internal space 5 is connected to a coolant sink (also
not further shown), for example, the suction side of a pump so that
the coolant flow shown with the arrows occurs. Water is used as
coolant so that a temperature lying significantly below the minimal
temperature which is 300.degree. C. in this example is set on the
outside of the outer tube 2.
[0022] The outside of the outer tube 2 is provided with a jacket
tube 8 by means of a spacer 7. The jacket tube 8 is also closed
vacuum-tight relative to the vacuum chamber 4.
[0023] A flow space, namely a narrow gap 9 between the outside of
outer tube 2 and jacket tube 8 is created by the spacer 7. This gap
9 is connected to a source for a heat exchange medium, in this case
helium, and to a sink so that flow of heat exchanger medium occurs
in gap 9. Helium can be used because of its very high heat
conductivity. Water is also possible as a good heat conductor. In
principle, however, other gases can be used, if their heat
conduction for the specific task is sufficient with expert
knowledge.
[0024] The heat transfer resistance and therefore the temperature
on the outside of the jacket tube 8 can be adjusted by the pressure
and/or flow rate and/or gas composition of the heat exchanger
medium so that it does not surpass a minimum temperature.
[0025] Since the heat transported away by the absorber also depends
on the pressure of the gas in the gap, this effect can also be
exploited by setting the gas pressure so that the desired heat
increase (while maintaining a temperature of, for example,
300.degree. C.) is taken off as absorber.
[0026] 16 shows the case in which the heat is taken off via the
helium in the gap and only heat conduction or helium plays a role
here. The absorber tube 8 can also be cooled by pumping helium or
another gas in circulation and passing it either outside of the
exchanger or using the inner water-traversed tube as a heat
exchanger surface.
[0027] As shown in 15 the absorbers 1 are arranged across the
transport direction 10 of the substrates 11, in which the
substrates 11 are passed by an evaporator source 14. Since the
evaporator source 12 has a very high temperature, the substrates 11
would experience a significant thermal load. The absorbers 1
prevent this.
[0028] For heat control of the process heaters 13 are also
provided. The chamber wall 3 is protected from the hot processes by
heat insulation 14.
[0029] The outside temperature of the jacket tube can also be
measured via a temperature sensor 15 so that it is guaranteed that
the minimum temperature is not fallen short of.
[0030] To improve the absorption effect the jacket tube 8 is
provided with surface-enlarging elements 16.
[0031] As shown in FIG. 3 additional absorbers 17 according to the
invention are arranged across the transport direction 10 on the
side of the substrates 11 on which the evaporator source 14 is
situated. These additional absorbers 17 serve to trap the heat
radiation that is reflected on the coating side of the substrates
11.
LIST OF REFERENCE NUMBERS
[0032] 1 Absorber [0033] 2 Outer tube [0034] 3 Chamber wall [0035]
4 Vacuum chamber [0036] 5 Internal space [0037] 6 Inner tube [0038]
7 Spacer [0039] 8 Jacket tube [0040] 9 Gap [0041] 10 Transport
direction [0042] 11 Substrate [0043] 12 Evaporator source [0044] 13
Heater [0045] 14 Heat insulation [0046] 15 Temperature sensor
[0047] 16 Surface-enlarging elements [0048] 17 Additional
absorber
* * * * *