Coating apparatus – Gas or vapor deposition – Work support
Reexamination Certificate
2000-02-08
2002-04-02
Knode, Marian C. (Department: 1763)
Coating apparatus
Gas or vapor deposition
Work support
C118S500000, C156S345420
Reexamination Certificate
active
06364957
ABSTRACT:
BACKGROUND
The invention relates to supporting a substrate in a chamber.
In substrate processing chambers, particularly vacuum processing chambers used to deposit and/or etch substrates, such as semiconductor wafers, a plasma may be used to process a surface of the substrate. The plasma may be formed by an electric field that is created between electrodes in the chamber, or is induced in the gas by passing an electrical current through a coil outside the chamber. However, the plasma in the processing chambers may react not only with the surface of the substrate being processed but with other exposed surfaces as well. The rate of reaction and/or erosion is dependent on the surface properties, such as a resistance of the exposed material to the active species of the plasma. The plasma may extend across the surface of the substrate all the way to its edge.
A typical configuration for supporting a substrate
15
exposed to a plasma on a pedestal assembly in a processing chamber
330
is shown
FIG. 1
a
. The pedestal assembly
340
includes a series of lower supports
344
,
346
and a series of outer rings
348
,
350
surrounding a substrate support member
343
. The upper outer ring
350
, which may be a focus ring composed of a dielectric material, may also be exposed to the deleterious effects of the plasma as it extends over the edge of the substrate
15
. The outer ring
350
may be made of alumina to be resistant to the plasma.
A close-up of the construction of an upper corner (see circle
349
) of a prior art pedestal assembly
340
is shown in
FIG. 1
b
with a dielectric collar ring
352
, which may be a focus ring
350
. The focus ring may preferentially direct gas species onto the substrate
15
. The collar ring
352
surrounds the substrate
15
to be processed. The substrate support member
343
, which may be made of aluminum, may be configured to extend to the edge of the substrate
15
it supports to provide more uniformity in the temperature of the substrate
15
. The collar ring
352
, which may be made of alumina or other plasma compatible ceramic material, surrounds the edge of the substrate
15
and acts as a barrier to protect the sidewalls of the aluminum substrate support member
343
from exposure to plasma. The larger thermal expansion coefficient and related expansion of the aluminum support member
343
may be accommodated by having enlarged dimensions for the surrounding collar ring
352
which has a comparatively small coefficient of thermal expansion. Therefore, large expansion gaps
360
,
362
may be provided between the outer perimeter of the substrate support member
343
and the collar ring
352
so that as the aluminum support member
343
expands it does not cause the surrounding collar ring
352
to fracture. Process gas may leak through the gaps, or a plasma may be formed therein that leads to corrosion or erosion of material adjacent the gaps.
Similar substrate support pedestal assemblies can be used in the other processing chambers, for example a side exhaust-metal etch chamber (
FIG. 2
a
), a bottom exhaust metal deposition/etch chamber (
FIG. 2
b
), or a chemical vapor deposition chamber (
FIG. 2
c
).
Therefore, it is desirable to have a support assembly capable of compensating for the thermal expansion of one or more components of the support assembly. It is further desirable to have an erosion resistant support assembly. It is also desirable for a support assembly to provide a gas flow restrictive seal. It is still further desirable to reduce the gaps within a support assembly.
SUMMARY
The present invention satisfies these needs. In one aspect of the invention, a substrate support assembly comprises a support comprising a substrate supporting surface and a collar comprising at least one slit.
In another aspect of the invention, a substrate support assembly comprises a support comprising a substrate supporting surface, the support having an outer diameter, and a collar around the support, the collar having an inner diameter less than the outer diameter of the support.
In another aspect of the invention, a substrate processing chamber comprises a substrate support assembly comprising a support and a collar at least partially around the support, the collar comprising a slit, a gas distributor, a gas energizer, and a gas exhaust, whereby a substrate received on the support assembly may be processed by gas introduced through the gas distributor, energized by the gas energizer and exhausted by the gas exhaust.
In another aspect of the invention, a method of supporting a substrate in a process chamber and processing the substrate in the process chamber comprises supporting the substrate on a support assembly in the process chamber, the support assembly comprising a collar at least partially around a support, providing an energized process gas in the process chamber, heating at least a portion of the support assembly, and providing a slit in the collar that is sized and shaped to compensate for a thermal expansion of the support or the collar.
In another aspect of the invention, a method of fabricating a substrate support assembly comprises forming a collar sized to fit around a support and forming a slit in the collar.
In another aspect of the invention, a method of fabricating a substrate support assembly comprising forming a support having an outer diameter, forming a collar having an inner diameter smaller than the outer diameter of the support, and providing the collar around at least a portion of the support.
In another aspect of the invention, a collar for a substrate support assembly comprises a ring adapted to fit around a support and a slit in the ring.
In another aspect of the invention, a collar for a support assembly comprises a ring adapted to fit around a support and an inner surface on the ring adapted to be biased against an outer surface on the support.
In another aspect of the invention, a substrate support assembly comprises a support comprising a substrate supporting surface and a collar abutting the support.
In another aspect of the invention, an apparatus comprises a first split ring configured to substantially surround a substrate support surface of a substrate support member, said split ring having an inner surface in substantially continuous contact with a perimeter surface of said substrate support member, wherein when said split ring is positioned adjacent to said substrate support member a top surface of said split ring is approximately an outward extension of the substrate support surface of said substrate support member.
In another aspect of the invention, a method of reducing the loss of material at the edge of a substrate support member in a processing chamber comprises providing a recess at the perimeter of the substrate support member and providing a first split ring in said recess with an inside surface of said ring in substantially continuous contact with an inside surface of said recess, such that a top surface of said split ring forms an extension of a substrate support surface of said substrate support member.
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Dao Hung
Lee Evans
Mays Brad Leroy
Noorbakhsh Hamid
Pu Bryan
Applied Materials Inc.
Bach Joseph
Hassanzadel P.
Janah and Associates
Knode Marian C.
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