Abrading – Precision device or process - or with condition responsive... – Tape controlled
Reexamination Certificate
2002-01-08
2004-04-06
Nguyen, George (Department: 3723)
Abrading
Precision device or process - or with condition responsive...
Tape controlled
C451S388000, C451S398000, C451S288000, C451S289000
Reexamination Certificate
active
06716084
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to semiconductor processing technologies and, more particularly, to a semiconductor wafer processing system.
2. Description of the Related Art
In the semiconductor industry, various processes can be used to deposit and etch materials on the wafers. These processes include material removal processes, such as chemical mechanical polishing (CMP), and deposition processes, such as electro chemical deposition (ECD).
Other material removal and deposition processes have more recently been introduced. These include electrochemical mechanical processing (ECMPR) including electrochemical mechanical deposition (ECMD) and electrochemical mechanical etching (ECME), which are described in U.S. Pat. No. 6,176,992 entitled “Method and Apparatus For Electro Chemical Mechanical Deposition”, commonly owned by the assignee of the present invention.
In the ECMD process, a conductor such as copper may be deposited on a semiconductor wafer or a work piece by having electrical current carried through an electrolyte that comes into contact with the surface of the wafer (cathode). The ECMD process, in one aspect, is able to uniformly fill the holes and trenches on the surface of the wafer with the conductive material while maintaining the planarity of the surface.
In the ECME process, a conductor such as copper previously deposited on a semiconductor wafer or a work piece can be removed by having electrical current carried through an electrolyte that comes into contact with the surface of the wafer (anode). The ECME process, in one aspect, is able to uniformly remove the conductor in a planar manner, thus maintaining the planarity of the surface.
A more detailed description of the ECMPR methods and apparatus can be found in the U.S. Pat. No. 6,176,992, noted above.
As generally exemplified in
FIG. 1
, the ECMPR system
10
, being used for ECMD, includes a deposition chamber
12
which contains an anode
14
, a pad
16
having openings
18
and an electrolyte
20
filling the chamber
12
. The anode
14
may be attached to the bottom of the chamber
12
. Further, a carrier head
22
having a rotatable shaft
23
holds and positions the wafer
24
against the pad
16
. The wafer
24
is placed on a surface
26
of a carrier base
28
(chuck) of the carrier head
22
. During the deposition and mechanical material removal steps, the carrier head secures
22
the wafer
24
to the surface
26
of the base
28
of the carrier head
22
by applying vacuum to the back of the wafer and using clamps
30
. Vacuum is applied using vacuum lines
32
extending through the carrier base
28
and the body of the carrier head
22
. Clamps
30
may also seal the electrical contacts to the wafer
24
. During the material removal step, the carrier head provides a controllable load to the wafer to push it against the pad. A more detailed description of the carrier head may be found in the co-pending U.S. application Ser. No. 09/472,523, entitled “Work Piece Carrier Head For Plating and Polishing” filed Dec. 27, 1999, commonly owned by the assignee of the present invention. For a detailed description of the pad, reference can be made to assignee's co-pending application Ser. No. 09/511,278, entitled “Pad Design and Structures For a Versatile Materials Processing Apparatus” filed Feb. 23, 2000, the specification of which is incorporated by reference herein as non-essential matter.
During an ECMPR, the wafer carrier holds the wafer with proper vacuum suction. As a result, the wafer does not become detached by the application of a weak vacuum. Further, it is important that the wafer not become damaged by the application of a high vacuum suction. During ECMPR, back side of the wafer should not be exposed to the processing solutions, which could be a plating electrolyte. Also, in conventional CMP processes, during the process the wafer is held by a retaining ring that is placed around the circumference of the carrier head. Such systems allow process solutions, such as slurry, to wet the back side of the wafer during the CMP process. Conventional CMP systems do not use vacuum suction during the CMP process to hold the wafer on the carrier. Therefore there is a need in the industry for ECMPR or CMP systems that do not expose back side of the wafer to the processing solutions such as electrolyte or slurries.
Also, in such processes, a resilient cushion on which the backside of the wafer can rest should be provided. Methods and apparatus providing fall face contact for processing on the front face of the wafer while providing the above considerations are desirable in the industry.
To this end, there is a need for alternative carrier head designs.
SUMMARY OF THE INVENTION
It is an object of the present invention, therefore, to provide an improved carrier head.
It is a further object of the present invention to provide an improved carrier head that is usable for either electrochemical mechanical processing and chemical mechanical processing.
It is a further object of the present invention to provide a carrier head that does not expose the back of a wafer to processing solution, provides full face contact for processing on the front face of the wafer, and provides a resilient cushion on which the backside of the wafer can rest.
These and other objects of the invention, either singly or in combination, are achieved by the present invention. Most generally, the present invention uses some type of inflatable membrane during processing to establish a vacuum and/or provide a resilient cushion on which the backside of the wafer can rest.
In one aspect, the present invention provides an outer vacuum that allow for attachment of the wafer to the carrier head during processing, and also provides an inner inflatable membrane that provides a resilient cushion on which the backside of the wafer can rest during processing.
In other aspects, the present invention provides a membrane that is displaceable with a vacuum within certain cavity regions to provide for attachment of the wafer to the wafer carrier.
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Basol Bulent M.
Uzoh Cyprian E.
Volodarsky Konstantin
Nguyen George
Nutool, Inc.
Pillsbury & Winthrop LLP
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