Coating apparatus – Gas or vapor deposition – Work support
Reexamination Certificate
1997-03-17
2001-04-10
Jones, Deborah (Department: 1775)
Coating apparatus
Gas or vapor deposition
Work support
C118S728000, C118S500000
Reexamination Certificate
active
06214122
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to rapid thermal processing of semiconductor substrates and more specifically to platforms for supporting and transferring heat to the substrate.
BACKGROUND OF THE INVENTION
In the fabrication of semiconductor devices, temperature treatment of the semiconductor substrate (herein after referred to as a wafer) is a necessary process step. Rapid thermal processing is often used during the processing of semiconductor devices for annealing materials, curing layers and activating compounds to name a few, and performed in a rapid thermal process tool. While effective in heating the wafer, the radiation pattern from the heating elements of the tool causes temperature variations in the material of the wafer. Temperature variations in the wafer cause, for example, material phase differences, doping nonuniformities, and stress gradients which are detrimental to the fabrication process.
The temperature variations are reduced by providing a susceptor carrying the wafer. A conventional susceptor is a container having a flat bottom upon which the wafer is placed. A lid is used to reduce convection currents near the wafer so the wafer is heated by transfer of heat from the bottom of the susceptor. The use of a susceptor minimizes temperature variations in the substrate. However, in very sensitive materials, temperature variations result from mechanical contact between the susceptor and the wafer, with flatness of the susceptor being critical to insure good mechanical contact which results in uniform thermal distribution. Any unevenness in the susceptor or the wafer will result in non-uniform thermal contact and temperature variation.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
Accordingly, it is an object of the present invention to provide an new improved rapid thermal processing susceptor.
Another object of the present invention is to provide a rapid thermal processing susceptor which improves thermal uniformity and reproducibility of the temperature in wafers.
And another object of the present invention is to provide a rapid thermal processing susceptor which minimizes the thermal contact area between susceptor and wafer.
Still another object of the present invention is to provide a rapid thermal processing susceptor which minimizes backside contamination and cross contamination of wafers.
Yet another object of the present invention is to provide a rapid thermal processing susceptor in which the dimensions can be manipulated in specific applications to heat the surfaces of a wafer differently.
And still another object of the present invention is to provide a rapid thermal processing susceptor which improves the gas flow within the susceptor.
A further object of the present invention is to provide a rapid thermal processing susceptor which can be employed with an automated rapid thermal processing tool.
SUMMARY OF THE INVENTION
Briefly, to achieve the desired objects of the instant invention, in accordance with a preferred embodiment thereof, provided is a rapid thermal processing susceptor including a base having a planar surface and an upright sidewall extending around a periphery thereof and encircling a working portion of the planar surface. The working portion and the sidewall define a cavity. A plurality of minimum contact points extend from the working portion into the cavity and are positioned to receive thereon a semiconductor wafer. A cover is receivable by the sidewall for enclosing the cavity.
In accordance with a further embodiment of the invention, provided is a rapid thermal processing susceptor for use in an automated rapid thermal processing tool. The susceptor includes a base having an upright sidewall extending around the periphery thereof and defining a cavity. A plurality of lift mechanism receiving openings are formed through the base, and a plug is positioned in the cavity and has an upper surface. An insert having a cut-out and an upper surface is movable between a raised position and a lowered position. In the lowered position the insert is positioned in the cavity with the plug received in the cut-out and the upper surface of the plug and the upper surface of the insert defining a planar surface within the cavity. A plurality of minimum contact points extend from the upper surface of the insert and are positioned to receive thereon a semiconductor wafer. A cover is receivable by the sidewall for enclosing the cavity.
REFERENCES:
patent: 4978567 (1990-12-01), Miller
patent: 5238499 (1993-08-01), Van de Ven et al.
patent: 5580388 (1996-12-01), Moore
patent: 5863843 (1999-01-01), Green et al.
Dauksher William J.
Melnick Bradley M.
Thompson Danny L.
Jones Deborah
Koch William E.
Miranda Lymarie
Motorola Inc.
Parsons Eugene A.
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