Chemical apparatus and process disinfecting – deodorizing – preser – Process disinfecting – preserving – deodorizing – or sterilizing – Process of storage or protection
Reexamination Certificate
2000-03-23
2004-12-21
Warden, Sr., Robert J. (Department: 1744)
Chemical apparatus and process disinfecting, deodorizing, preser
Process disinfecting, preserving, deodorizing, or sterilizing
Process of storage or protection
C422S028000, C422S123000, C422S261000, C422S294000, C422S300000, C422S305000, C015S077000, C451S034000, C451S057000, C451S065000, C451S066000, C134S002000, C134S019000, C134S026000, C134S030000, C134S042000, C134S061000, C134S902000, C438S690000, C438S691000, C438S692000, C438S693000, C510S175000, C510S245000, C510S252000, C510S254000, C510S255000, C510S258000
Reexamination Certificate
active
06833109
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for storing a polished semiconductor wafer after its CMP (i.e., chemical mechanical polishing) process, and more particularly to the method and apparatus for temporarily storing the polished semiconductor wafer in a water tank after its CMP process and before its post-CMP cleaning process, in which the post-CMP cleaning process abrasives (i.e., abrasive grains or powder) for example such as those of alumina, silica, oxidizing agents, or of like substances) used in the CMP process and the wafer's debris remaining on the surface of the polished semiconductor wafer are removed.
2. Description of the Related Art
In a conventional process for forming a metallic wiring in a surface of a semiconductor wafer through a so-called “damascene process”: first, an insulation film is formed on a surface of a semiconductor substrate which is constructed of the semiconductor wafer; secondly, a wiring trench and/or a connecting hole connected with a lower wiring layer is formed in the insulation film; and, lastly, the metallic wiring and/or a connecting plug is formed by forming a metallic wiring film of copper or like metal on the semiconductor substrate through an electroplating process of copper or like metal and then removing excess metal or excess copper from the metallic wiring film through a CMP operation to form metallic wiring and/or a connecting plug on the semiconductor substrate.
After completion of the CMP operation, any abrasive and any debris of the thus polished semiconductor wafer are removed from the surface of the polished semiconductor wafer through a post-CMP cleaning operation which follows the CMP operation. In general, at this time, there is a predetermined period of wafer's waiting time between the CMP operation and such post-CMP cleaning operation of the polished semiconductor wafer. In case that the surface of the polished semiconductor wafer becomes dry in the above-mentioned wafer's waiting time, it becomes very hard to remove both the abrasive and the debris of the polished semiconductor wafer from such dried surface. Consequently, in order to keep the surface of the polished semiconductor wafer wet after polishing, the polished-semiconductor wafer having been subjected to the CMP operation is immersed in pure water of a water tank during the above-mentioned wafer's waiting time, as disclosed in Japanese Patent Laid-Open No. Hei 10-214802.
FIG. 9
is a flowchart of process steps performed after completion of the CMP operation of the Cu (i.e., copper) wiring of the semiconductor wafer when a Cu damascene wiring is formed according to a conventional method, illustrating both a conventional CMP unit for CMP polishing the copper, wiring and a conventional post-CMP cleaning unit.
In general, a plurality of (i.e., approximately ten to thirty semiconductor wafers are housed in a wafer carrier to form a batch-processed work called a “lot”) which is transferred between adjacent carriers of a plurality of processing units.
In a process step S
1
of the flowchart shown in
FIG. 9
, the polished semiconductor wafer has a Cu film formed on its surface in a Cu film formation unit. Then, the process step S
1
is followed by a subsequent process step S
2
. As a result, the “lot” is transferred from the above Cu film formation unit to a loader chamber
11
of a copper chemical mechanical polishing (i.e., Cu-CMP) unit
10
.
More specifically, in the process step S
2
for performing the Cu-CMP operation, a set of the polished semiconductor wafers of approximately one to four pieces is retrieved from the wafer carrier having been mounted in the loader chamber
11
, is set in a polishing chamber
13
of the Cu-CMP unit
10
and subjected to the CMP process. Since the polished semiconductor wafer has a diameter of approximately 30 cm, it is not practical to prepare a CMP unit which is capable of treating the above-mentioned “lot” of large-diameter semiconductor wafers at a time because of an enormous size of such CMP unit, wherein the “lot” is composed of a plurality of such large-diameter semiconductor wafers.
Consequently, in the process step S
2
shown in the flowchart of
FIG. 9
, in general, approximately one to four semiconductor wafers are treated at a time. After completion of the CMP operation, these polished semiconductor wafers are housed in another wafer carrier provided in an unloader chamber
12
of the CMP unit
10
, and enter a waiting mode in this unloader chamber
12
and kept therein until another wafer carrier is filled with these polished semiconductor wafers having been subjected to the CMP operations. On the other hand, this unloader chamber
12
is provided with a wafer storing water tank (not shown), in which the thus polished semiconductor wafers are stored in water, and thereby preventing their surfaces from becoming dry after completion of their CMP polishing operations.
After completion of the process step S
2
for performing the Cu-CMP operations of copper or metallic wirings of the polished semiconductor wafers of the above-mentioned “lot”, another wafer carrier is transferred from the unloader chamber
12
to a loader chamber
16
of a post-CMP cleaning unit
14
to enter a process step S
3
subsequent to the process step S
2
. In the process step S
3
, the “lot” is subjected to the post-CMP cleaning process. On the other hand, the loader chamber
16
of the post-CMP cleaning unit
14
is also provided with another wafer storing water tank for receiving the polished semiconductor wafers having been subjected to the CMP operations, wherein these polished semiconductor wafers are stored in water of another water tank to prevent their surfaces from drying.
In the post-CMP cleaning unit
14
shown in
FIG. 9
, a cleaning or post-CMP cleaning chamber
15
is disposed adjacent to the loader chamber
16
. Consequently, the polished semiconductor wafers are transferred from the loader chamber
16
to this post-CMP cleaning chamber
15
singly and successively, then subjected to scrubbing operations with the use of both a brush and a cleaning liquid issued to the individual polished semiconductor wafers, and lastly rinsed out with the use of alcohol and water. After that, the polished semiconductor wafers thus rinsed out are dried in a drying chamber
17
. This drying chamber
17
is disposed adjacent to the post-CMP cleaning chamber
15
, as shown in FIG.
9
. The polished semiconductor wafers thus dried up are then transferred to further another wafer carrier
22
which is provided in an unloader chamber
19
disposed adjacent to the drying chamber
17
.
After completion of the post-CMP cleaning operation in the process step S
3
, the process step S
3
is followed by its subsequent process step S
4
. In this subsequent process step S
4
, for example, a cover film is formed on the surface of each of the polished semiconductor wafers of the further another wafer carrier.
Shown in
FIG. 10
is a conventional apparatus for storing the polished semiconductor water in a wafer storing water tank
18
thereof. In this conventional apparatus, the polished semiconductor wafer is immersed in pure water received in the wafer storing water tank
18
. More specifically, as shown in
FIGS. 9 and 10
, the wafer storing water tank
18
shown in
FIG. 10
is installed in the unloader chamber
12
(shown in
FIG. 9
) of the CMP unit
10
, and also installed in the loader chamber
16
(shown in
FIG. 9
) of the post-CMP cleaning unit
14
. In operation, the wafer storing water tank
18
is filled with pure water
43
, so that the polished semiconductor wafers
20
housed in the wafer carrier
22
are immersed in the pure water
43
of the wafer storing water tank
18
, to which tank
18
the pure water is constantly supplied from the outside.
There is another conventional method, in which the polished semiconductor wafers are not immersed in the pure water
43
but sprayed with pure water. Shown in
FIG. 11
is a part of a conventional apparatus carryin
Aoki Hidemitsu
Yamasaki Shinya
Chorbaji Monzer R.
NEC Electronics Corporation
Warden, Sr. Robert J.
Young & Thompson
LandOfFree
Method and apparatus for storing a semiconductor wafer after... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for storing a semiconductor wafer after..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for storing a semiconductor wafer after... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3278803