Stationary and pivotable trays for semiconductor wafer transfer

Details Stationary and pivotable trays for semiconductor wafer transfer Stationary and pivotable trays for semiconductor wafer transfer

2001-11-19

2003-11-25

Maust, Timothy L. (Department: 3751)

Fluent material handling, with receiver or receiver coacting mea

With soil removing, coating, lubricating, sterilizing and/or...

Drip collection

C141S001000, C141S098000, C141S163000, C414S935000, C414S940000

Reexamination Certificate

active

06651704

ABSTRACT:

FIELD OF THE INVENTION
This invention relates generally to the transfer of semiconductor wafers among various semiconductor processing stations as well as other types of stations, and more particularly to collecting liquid dripping from moving equipment during such transfer.
BACKGROUND OF THE INVENTION
Semiconductor fabrication requires that a semiconductor wafer be processed in a variety of different manners. A wafer may be coated with photoresist, exposed to an ultraviolet light source to imprint a device pattern on the wafer, developed to remove the exposed photoresist, etched, and so on. Each different type of processing may require that the wafer be moved to a different processing station that is particular to a given type of processing. Therefore, the wafer must usually be transferred among different processing stations in order to fabricate devices on the wafer.
FIG. 1
shows an example system
100
in which wafer transfer is accomplished between a primary unit
102
and a secondary unit
104
, as separated conceptually by a dotted line
106
and physically by a wall
110
. A chuck
108
having arms
132
moves a container
128
horizontally between the primary unit
102
and the secondary unit
104
. The chuck
108
may be such a chuck as manufactured by and available from Robotek International, of Richardson, Tex. The chuck container
128
is more specifically a boat or a cassette. The container
128
moves horizontally as indicated by the arrows
114
and
116
. On the side of the primary unit
102
, the chuck
108
may at least assist in submersing the container
128
, and its contained semiconductor wafers, in an immersion tank
112
, for a wet bench process. The chuck
108
may thus move the container
128
to the container position
131
.
On the side of the secondary unit
104
, a robotic arm
118
is able to move the container
128
vertically into and out of the plane of
FIG. 1
, as indicated by the in circle
120
and the out circle
122
, once the container
128
has been deposited by the chuck
108
in the container position
130
. The robotic arm
118
is able to accomplish its movement of the container
128
as a result of its arm
126
. The arm
126
, as well as the container position
130
, is over a stage
124
of the secondary unit
104
, as compared to the container position
131
, which is over and/or in the tank
112
on the side of the primary unit
102
. The robotic arm
118
may be such an arm as manufactured by and available from Kaijo Corp., of Tokyo, Japan. The robotic arm
118
is for moving from a container loading and unloading position, not shown in
FIG. 1
, to the container position
130
, which is a wafer loading and unloading position. By comparison, the container position
131
is a wafer tank immersion position, such that the wafers can be immersed into the tank at this position. The position
131
may alternatively be located in the tank
112
as well.
A problem with the transfer of semiconductor wafers via the system
100
of
FIG. 1
is that the caustic chemicals, or other liquid, in which the container
128
is immersed in the tank
112
may drip off chuck
108
when it is moving over the secondary unit
104
. The caustic chemicals are those necessary for performing a wet bench operation on the semiconductor wafers held within the container
128
. This can cause significant and rapid corrosion of the secondary unit
104
, as well as the robotic arm
118
and its arm
128
. The chuck
108
and the robotic arm
118
are more generally referred to as moving equipment, insofar as they move, or transfer, the container
128
and its contained semiconductor wafers.
A limited solution to this problem is to clean the chuck
108
before it is moved over the secondary unit
104
. For instance, there may be a chuck-cleaning bath in which overflowing deionized water and/or blowing nitrogen clean the residual chemicals from the chuck
108
. However, this is disadvantageous a at best. Chuck cleaning prolongs the transfer time from the primary unit
102
to the secondary unit
102
, such as by nearly sixty seconds. This lowers the number of wafers that can be processed on a per hour basis, increasing cost to the semiconductor manufacturer. Furthermore, extra facility space is required to house the chuck cleaning bath, which may be expensive at best or not always available at worst. Finally, the cleaning bath cannot completely clean the chuck
108
. Therefore, liquid dripping from the chuck
108
is only at best reduced, and thus at best only slows corrosion of the secondary unit
104
.
Therefore, there is a need within the art to overcome these disadvantages. Specifically, there is a need to prevent the chuck
108
from corroding the secondary unit
104
and the robotic arm
118
when it is moving over the secondary unit
104
. There is a need for complete prevention of such corrosion, and not just a decrease in the rate of corrosion. There is a need to prevent corrosion without slowing down the number of wafers that can be processed on an hourly basis, as well as without requiring extra space in the facility. For these and other reasons, there is a need for the present invention.
SUMMARY OF THE INVENTION
The invention relates to stationary and pivotable trays for semiconductor wafer transfer. A first moving equipment, such as a chuck, is movable to move a container for holding one or more semiconductor wafers from a wafer loading and unloading position to a wafer tank immersion position. A second moving equipment, such as a robotic arm, is movable to move the container from the wafer loading and unloading position to a container loading and unloading position. A stationary tray is located under the wafer loading and unloading position to collect liquid dripping from the first moving equipment. A pivotable tray is located to one side of the stationary tray, to collect the liquid dripping from the first moving equipment when this equipment is moving to the wafer loading and unloading position, such that the pivotable tray is lowered. The pivotable tray is raised when the second moving equipment is moving to the wafer loading and unloading position.
The invention provides for advantages over the prior art. The stationary and pivotable trays prevent the liquid dripping from the first moving equipment from corroding the second moving equipment, or other equipment, such as a secondary unit. The trays collect the dripping liquid, such that the first moving equipment does not have to be cleaned in a time-consuming bath, and such that the number of wafers that can be processed on an hourly basis is not decreased. Furthermore, the trays do not use potentially expensive facility space. Other advantages, embodiments, and aspects of the invention will become apparent by reading the detailed description that follows, and by referencing the attached drawings.


REFERENCES:
patent: 5301700 (1994-04-01), Kamikawa et al.
patent: 5478195 (1995-12-01), Usami
patent: 5628121 (1997-05-01), Brooks et al.
patent: 5740845 (1998-04-01), Bonora et al.

Affiliated with

Also associated with

Rating

Stationary and pivotable trays for semiconductor wafer transfer does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Stationary and pivotable trays for semiconductor wafer transfer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stationary and pivotable trays for semiconductor wafer transfer will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3173537