Etching a substrate: processes – Nongaseous phase etching of substrate – Etching inorganic substrate
Reexamination Certificate
2001-12-07
2004-04-27
Powell, William A. (Department: 1765)
Etching a substrate: processes
Nongaseous phase etching of substrate
Etching inorganic substrate
C134S031000, C134S186000, C156S345110, C216S099000, C438S745000
Reexamination Certificate
active
06726848
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of surface preparation systems and methods for semiconductor substrates and the like.
BACKGROUND OF THE INVENTION
In certain industries there are processes that must be used to bring objects to an extraordinarily high level of cleanliness. For example, in the fabrication of semiconductor substrates, multiple cleaning steps are typically required to remove impurities from the surfaces of the substrates before subsequent processing. The cleaning of a substrate, known as surface preparation, has for years been performed by collecting multiple substrates into a batch and subjecting the batch to a sequence of chemical and rinse steps and eventually to a final drying step. A typical surface preparation procedure may include etch, clean, rinse and dry steps. An etch step may involve immersing the substrates in an etch solution of HF to remove surface oxidation and metallic impurities and then thoroughly rinsing the substrates in high purity deionized water (DI) to remove etch chemicals from the substrates. During a typical cleaning step, the substrates are exposed to a cleaning solution that may include water, ammonia or hydrochloric acid, and hydrogen peroxide. After cleaning, the substrates are rinsed using ultra-pure water and then dried using one of several known drying processes.
Currently, there are several types of tools and methods used in industry to carry out the surface preparation process. The tool most prevalent in conventional cleaning applications is the immersion wet cleaning platform, or “wet bench.” In wet bench processing, a batch of substrates is typically arranged on a substrate-carrying cassette. The cassette is dipped into a series of process vessels, where certain vessels contain chemicals needed for clean or etch functions, while others contain deionized water (“DI”) for the rinsing of these chemicals from the substrate surfaces. The cleaning vessels may be provided with piezoelectric transducers that propagate megasonic energy into the cleaning solution. The megasonic energy enhances cleaning by inducing microcavitation in the cleaning solution, which helps to dislodge particles off of the substrate surfaces. After the substrates are etched and/or cleaned and then rinsed, they are dried. Often drying is facilitated using a solvent such as isopropyl alcohol (IPA), which reduces the surface tension of water attached to the substrate surface.
Another type of surface preparation tool and method utilized in the semiconductor industry is one in which a number of surface preparation steps (e.g. clean, etch, rinse and/or dry) may be performed on a batch of substrates within a single vessel. Tools of this type can eliminate substrate-transfer steps previously required by wet bench technology, and have thus gained acceptance in the industry due to their reduced risk of breakage, particle contamination and their reduction in footprint size.
Further desirable, however, is a chamber and method in which multiple surface preparation steps can be performed on a single substrate (e.g. a 200 mm, 300 mm or 450 mm diameter substrate), as opposed to a batch of substrates. It is thus an object of the present invention to provide a chamber and method for performing one or more surface preparation steps on a single substrate.
SUMMARY OF THE INVENTION
In one aspect of the present invention, a single substrate is positioned in a single-substrate process chamber and subjected to wet etching, cleaning and/or drying steps. According to another aspect of the present invention, a single substrate is exposed to etch or clean chemistry in the single-substrate processing chamber as boundary layer thinning is induced in the region of the substrate. According to yet another aspect of a method according to the present invention, boundary layer thinning is induced in a zone within the single-substrate process chamber, and a single substrate is translated through the zone during a process within the chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A
is a schematic illustration of a single substrate processing chamber, showing the substrate positioned in the lower interior region of the chamber.
FIG. 1B
is a schematic illustration of a single substrate processing chamber, showing the substrate positioned in the upper interior region of the chamber.
FIG. 1C
is a block diagram illustrating one example of a fluid handling system useable with the chamber of FIG.
1
A.
FIG. 1D
is a block diagram illustrating a second example of a fluid handling system useable with the chamber of FIG.
1
A.
FIGS. 2A-2C
are a sequence of cross-section views of the chamber interior, illustrating movement of the substrate between the upper interior region and the lower interior region.
FIG. 3A
is a cross-sectional perspective view of a second embodiment of a single substrate processing chamber showing the fluid manifold in the closed position. The figure also shows automation provided for transporting a substrate into, out of, and within the chamber.
FIG. 3B
is a cross-sectional perspective view of the single substrate processing chamber of
FIG. 3A
showing the fluid manifold in the opened position. The transport automation shown in
FIG. 3A
is not shown in FIG.
3
B.
FIG. 4
is a cross-sectional perspective view of the upper manifold and a portion of the tank of the second embodiment of FIG.
3
A.
FIG. 5
is a cross-sectional side view of the second embodiment of FIG.
3
A.
FIG. 6
is a perspective view of an end effector of the second embodiment of FIG.
3
A. The end effector is shown carrying a substrate.
FIG. 7A
is a perspective view of one prong of a second embodiment of an end effector during transport of a substrate.
FIG. 7B
is a perspective view showing the end effector of
FIG. 7A
during transport of a substrate into or out of the chamber.
FIG. 7C
is a perspective view showing the end effector, substrate and chamber during transport of the substrate into or out of the chamber, with the substrate beginning to make contact with the bottom notch of the chamber.
FIG. 7D
is a perspective view showing the end effector, substrate and chamber during processing of the substrate within the chamber.
FIG. 7E
is a perspective view similar to the view of
FIG. 7A
showing one prong of the end effector during processing of the substrate within the chamber.
FIG. 8
is a cross-section view of a chamber according to a third embodiment.
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patent: 1 168 422 (2001-06-01), None
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Patent Application Publication, Pub. No. US 2002/0016082, Feb. 7, 2002, corresponding to U.S. Appln. No. 09/892,269, filed Jun. 27, 2001, 24 pages in length.
Bleck Martin
Hansen Eric
Mimken Victor
Rosato John
Yalamanchili M. Rao
Powell William A.
SCP Global Technologies Inc.
Stallman & Pollock L.L.P.
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