Material or article handling – Apparatus for moving material between zones having different...
Reexamination Certificate
2000-10-20
2002-04-16
Bratlie, Steven A. (Department: 3652)
Material or article handling
Apparatus for moving material between zones having different...
C118S729000
Reexamination Certificate
active
06371712
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a substrate processing system in the electronics industry. More specifically, the invention relates to a system and method for supporting substrates in a substrate processing system.
2. Background of the Related Art
Substrates on which physical vapor deposition (PVD), chemical vapor deposition (CVD), etching, electroplating, planarization and other processes are performed are used to manufacture integrated circuits (ICs), flat panel displays (FPDs) and other electronic components. Round substrates, typically known as wafers, are used to create a plurality of ICs by cutting the wafers into individual die after deposition and other processing. The typical size for a semiconductor wafer is about 200 mm with a thickness of less than 0.5 mm and a mass of about 60 grams. Typical substrate processing requires planar support of the substrate to ensure uniform deposition across the substrate surface in the processing chamber. The relatively small size and light weight of the wafers require minimal structural support to retain a planar processing position.
Conceptually, FPDs are produced by similar processes as are performed in the fabrication of ICs, such as etching, deposition, and planarization. Generally, multiple metallic interconnects, liquid crystal cells and other devices are formed on a glass substrate to produce the FPD. The various devices are integrated into a system that collectively is used to create, for example, active matrix display screens in which display states are electrically created in individual pixels on the FPD. Overall processing uniformity across the entire surface of the FPD is critical for the FPD to function properly and defects in the FPD as a whole need to approach zero.
A typical glass substrate has increased in size from about 200 mm by 300 mm to about 680 mm by about 880 mm and a mass of about 2 to about 3 kilograms. The size is continuing to increase as the demand for larger screens or displays increases.
FIG. 1
is a schematic cross-sectional view of a processing chamber
2
, such as a CVD chamber having a top
4
, bottom
6
, sidewalls
8
, a support plate
18
and a susceptor
22
disposed therein to support an FPD substrate
12
. In general, CVD processing is the formation of a non-volatile solid layer on a substrate by the reaction of vapor phase chemicals, termed “reactants”, which contain the required constituents to be deposited. The reactants enter a system and are decomposed and/or reacted on a substrate to form a desired layer of material thereon. Reactive gases are flown through a gas inlet
14
into a gas manifold
16
that is mounted near the top of the chamber. An opening
10
is disposed in the sidewall
8
to allow a robot (not shown) to deliver and retrieve the substrate
12
to and from the chamber. A support plate
18
is coupled to a support stem
20
and supports the susceptor
22
. The support plate
18
is typically made of a single rectangular plate of ceramic material, such as aluminum oxide, and closely covers the area of the susceptor
22
. The susceptor
22
historically has been made of a single rectangular plate of aluminum and is typically heated with a heater (not shown) with energy supplied from a power source
24
. A susceptor sized to accommodate the larger substrates, such as a 680 mm by 880 mm substrate, can have a mass of about 130 kg. Even larger substrates may require a larger susceptor with a mass of about 230 kg.
Typical temperatures for CVD processes can reach up to about 430° C. Aluminum begins to exhibit “liquid” type properties at about 660° C. and, thus, at the operating ranges of the CVD processes, the aluminum susceptor
22
can deflect and “droop” without adequate support. The ceramic material of the support plate
18
has been used to support the ductile aluminum susceptor. However, ceramic is a relatively poor thermal conductor and, thus, demonstrates a temperature gradient between a hotter upper surface of the support plate
18
that contacts the heated susceptor and a cooler lower surface of the support plate
18
. The thermal gradient can cause the hotter upper surface of the substrate to expand a greater distance than the cooler lower surface, and as a result, the support plate
18
deflects downwardly at its outer perimeter. Furthermore, as the support plate
18
deflects, the ductile aluminum susceptor deflects in conformance with the deflected support plate. A substrate supported by the susceptor is prone to conform to the susceptor and, thus, also deflects. As a result, the vertical spacing between the gas manifold
16
and the substrate
12
varies between a central section of the substrate having a distance
34
from the manifold and a peripheral region having a greater distance
36
. The difference in spacing decreases deposition and other processing uniformity.
Therefore, there remains a need for a system having a support with reduced deflection for substrates, particularly larger substrates.
SUMMARY OF THE INVENTION
The present invention generally provides a system and method for supporting a substrate having a support frame that minimizes deflection encountered during thermal expansion in a processing chamber. In one embodiment, the support frame comprises one or more longitudinal members coupled to one or more transverse members. The transverse members preferably define a supporting surface on which a heated susceptor is mounted. The longitudinal member is preferably disposed below the heated susceptor, thus minimizing thermal expansion of the longitudinal member. Spacers made of thermally conductive material may be disposed at appropriate locations along the members to provide more uniform distribution of heat within the members and to compensate for vertical deflection.
In another aspect, the invention provides a substrate processing system, comprising at least one chamber, a robot disposed in proximity to the chamber, and a support frame having at least one longitudinal member and at least one transverse member coupled to the longitudinal member. In another aspect, the invention provides a system for supporting a susceptor, comprising a longitudinal member supporting one or more transverse members. In another aspect, the invention provides a system for supporting substrates with a support frame in a substrate processing system, the support frame comprising at least one longitudinal member and at least one transverse member coupled to the longitudinal member.
REFERENCES:
patent: 3830194 (1974-08-01), Benzing et al.
patent: 4455467 (1984-06-01), Dills
patent: 4522149 (1985-06-01), Garbis et al.
patent: 4809421 (1989-03-01), Justice
patent: 4927991 (1990-05-01), Wendt et al.
patent: 5000113 (1991-03-01), Wang et al.
patent: 5044943 (1991-09-01), Bowman et al.
patent: 5173580 (1992-12-01), Levin et al.
patent: 5332443 (1994-07-01), Chew et al.
patent: 5421893 (1995-06-01), Perlov
patent: 5611865 (1997-03-01), White et al.
patent: 5820686 (1998-10-01), Moore
patent: 6203622 (2001-03-01), Halpin et al.
Beer Emanuel
Chang Larry
White John M.
Applied Komatsu Technology Inc.
Bratlie Steven A.
Moser Patterson & Sheridan LLP
LandOfFree
Support frame for substrates does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Support frame for substrates, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Support frame for substrates will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2852250