Chemistry: electrical and wave energy – Processes and products – Coating – forming or etching by sputtering
Reexamination Certificate
2000-12-07
2002-03-19
McDonald, Rodney G. (Department: 1753)
Chemistry: electrical and wave energy
Processes and products
Coating, forming or etching by sputtering
C204S192130, C204S192260, C204S298030, C204S298250, C204S298260, C118S719000, C414S217000, C414S221000
Reexamination Certificate
active
06358377
ABSTRACT:
This invention relates to an apparatus for sputter coating glass, and corresponding method.
BACKGROUND AND SUMMARY OF THE INVENTION
Sputter coated glass articles are known in the art. For example, see U.S. Pat. Nos. 5,770,321, 5,298,048, and 5,403,458, the disclosures of which are all hereby incorporated herein by reference. Sputter coated layer systems on glass substrates are typically utilized for achieving solar management properties (e.g., low emissivity or low-E) in many types of glass articles, including but not limited to architectural windows, automotive windows, automotive windshields, and the like.
Sputter coating may be an electric discharge process, often conducted in a vacuum chamber in the presence of one or more gases. A sputter coating apparatus typically includes at least one vacuum chamber in which a substrate is located, a power source, an anode, and one or more specially prepared cathode targets of or covered with a material to be used in creating a layer on the substrate. When an electric potential is applied to the cathode target, the gas(es) forms a plasma that bombards the target causing particles of the coating material to be liberated or lifted from the target itself. The liberated coating material from the target falls onto the underlying substrate and adheres thereto. When conducted in the presence of a “reactive” gas, a reactive product of the coating material from the target and the gas may be deposited on the substrate.
Unfortunately, conventional sputter coating apparatuses suffer from certain inefficiencies, especially when one desires or needs to manufacture different types of sputter coated articles using the same sputter coating apparatus.
Consider, for purposes of examples only, a scenario where one wishes to manufacture the coated articles of
FIGS. 1 and 2
utilizing a sputter coating apparatus. The coated article of
FIG. 1
includes glass substrate
1
on which are located silicon nitride (Si
3
N
4
) layer
2
, nichrome or nichrox (NiCr or NiCrO
x
) layer
3
, silver (Ag) layer
4
, nichrome or nichrox (NiCr or NiCrO
x
) layer
5
, and silicon nitride (Si
3
N
4
) layer
6
. Optionally, another layer (e.g., a dielectric layer) may also be provided between substrate
1
and layer
2
. Further details regarding the coated article of
FIG. 1
may be found in U.S. Pat. No. 5,770,321, incorporated herein by reference. Meanwhile, the coated article of
FIG. 2
also includes layers
2
-
6
provided on glass substrate
1
. However, the coated article of
FIG. 2
further includes a thicker silicon nitride (Si
3
N
4
) layer
6
a
(instead of layer
6
shown in FIG.
1
), nichrome or nichrox (NiCr or NiCrO
x
) layer
7
, second silver (Ag) layer
8
, nichrome or nichrox (NiCr or NiCrO
x
) layer
9
, and silicon nitride (Si
3
N
4
) layer
10
. The coating system of
FIG. 2
may be referred to as a dual silver coating system because it includes first and second silver (Ag) layers
4
and
8
provided for infrared (IR) radiation reflection, respectively, as opposed to the single silver layer
4
provided in the coated article of FIG.
1
.
To manufacture both the coated article of FIG.
1
and the coated article of
FIG. 2
using the same sputter coating apparatus, one would typically obtain a sputter coating apparatus as shown in FIG.
3
. The
FIG. 3
sputter coating apparatus includes enough targets and zones to enable each of layers
2
-
10
to be deposited on a substrate
1
(i.e., it is large enough and has enough capacity to enable either the
FIG. 1
or the
FIG. 2
article to be made therein). In particular, the sputter coating apparatus includes six different zones (i.e., zones
1
-
6
) which are separated from one another by curtains or walls
52
. Zone
1
includes targets
21
-
26
. Zone
2
includes targets
27
-
29
. Zone
3
includes targets
30
-
35
. Zone
4
includes targets
36
-
41
. Zone
5
includes targets
42
-
44
. Zone
6
includes targets
46
-
50
. A different gas (e.g., argon, nitrogen, oxygen, etc.) may be utilized in each zone at low pressure, while vacuum pumps
51
are provided between zones in order to keep gaseous atmospheres from one zone from significantly leaking into an contaminating adjacent zone(s).
In order to manufacture the coated article of
FIG. 1
using the sputter coating apparatus of
FIG. 3
, a typical line speed of the sputter coater is 205 inches per minute for this five layer system. For the
FIG. 1
coating system to be deposited, targets
21
-
26
in zone
1
are silicon (Si) targets, while nitrogen gas at low pressure is provided in that zone. Following deposition of silicon nitride layer
2
in zone
1
using targets
21
-
26
, the substrate
1
passes into zone
2
via a conveyor. In zone
2
, targets
27
and
29
are of nickel and/or chrome, while target
28
is of silver. An argon (Ar) atmosphere may be utilized in zone
2
. After the nichrome layers
3
and
5
and silver layer
4
are deposited in zone
2
, a conveyor moves the substrate into zone
3
beneath targets
30
-
35
. In zone
3
, targets
30
-
35
are of silicon (Si) while a nitrogen (N
2
) gas at low pressure is utilized in that zone. Each of zones
1
-
3
may be maintained at a pressure of from about 1.0 to 3.0×10
−3
Torr, or any other pressure disclosed in any of the aforesaid '321, '048 and '458 patents. Upon leaving zone
3
, the coating system of
FIG. 1
will have been formed. Thus, zones
4
-
6
and their respective targets
36
-
50
are inoperative in the
FIG. 3
apparatus when the coated article of
FIG. 1
is deposited as discussed above. Unfortunately, the inoperation of these three zones
4
-
6
is wasteful, and also presents a requirement for passing a coated article through inoperative zones thereby leading to potential contamination and/or undesirable delay.
However, when it is desired to manufacture the coated article of
FIG. 2
utilizing the apparatus of
FIG. 3
, zones
1
-
3
are set up and utilized as described above regarding the
FIG. 1
article. In addition, zones
4
-
6
are set up just like zones
1
-
3
, respectively. Thus, the upper half of silicon nitride layer
6
a
and layers
7
-
10
are deposited in zones
4
-
6
. In other words, targets
36
-
41
are silicon targets in a nitrogen atmosphere of zone
4
, targets
42
and
44
are nickel and/or chrome targets in an argon atmosphere in zone
5
, target
43
is a silver target in the same argon atmosphere of zone
5
, and targets
45
-
50
are silicon targets in a nitrogen atmosphere of zone
6
. Thus, all six zones (i.e., zones
1
-
6
) are utilized when forming the layer system of the
FIG. 2
coated article.
Unfortunately, as can be seen from the above, it is often desired to manufacture coated articles of different types such as those of
FIGS. 1 and 2
. If this is to be done utilizing the same sputter coating apparatus, such an apparatus must be obtained which has enough zones and targets to enable the coating system having the largest number of layers to be manufactured. Thus, one desiring to manufacture the articles of both FIG.
1
and
FIG. 2
would have to purchase a sputter coating apparatus such as that shown in
FIG. 3
having sufficient zones and targets to accommodate the
FIG. 2
article. Unfortunately, many of these zones and targets are wasted and not utilized when only the article of
FIG. 1
is manufactured (i.e., certain zones and/or targets would likely be inoperative during manufacture of the
FIG. 1
article). In other words, a significant portion of the coating apparatus may not be used when certain coated articles having a small number of layer(s) are being manufactured. Yet another problem is that when it is desired to upgrade a particular sputter coating apparatus, the line (i.e., all zones
1
-
6
) must be shut down.
In view of the above, it will be appreciated by those skilled in the art that there exist a need for a sputter coating apparatus which can more efficiently manufacture sputter coated articles of different types without wasting significant resources (e.g., zones and/or targets).
Lemmer Jean-Marc
Schloremberg Marcel
Guardian Industries Corp.
McDonald Rodney G.
Nixon & Vanderhye P.C.
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