Cleaning and liquid contact with solids – Processes – With work or work parts movable during treatment
Reexamination Certificate
2001-09-24
2003-09-09
Gulakowski, Randy (Department: 1746)
Cleaning and liquid contact with solids
Processes
With work or work parts movable during treatment
C134S002000, C134S010000, C134S025100, C134S034000, C134S084000, C134S085000, C134S086000, C134S135000, C134S137000, C134S186000, C134S902000, C438S906000
Reexamination Certificate
active
06616774
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a wafer cleaning device and a tray for use in the wafer cleaning device, particularly to a wafer cleaning device in which a tray containing wafers is steeped in a cleaning tank and cleaning fluid is allowed to flow to clean the wafers and to a tray for use in the wafer cleaning device.
BACKGROUND ART
In a conventional method of manufacturing semiconductor wafers, a cleaning process is performed to rinse the surfaces of semiconductor wafers (hereinafter referred to as wafers) in chemical liquid, pure water or another cleaning fluid. A wafer cleaning device and a tray for use in the wafer cleaning device are used in the process. To maintain the performance and reliability of wafers, the wafer cleaning device and the tray are requested to have a high cleaning capability to reduce contaminant substances adhering to the surfaces of the wafers. Especially, in a large wafer having a diameter of 12 inches (300 mm), the cleaning effect is largely changed by the flow of the cleaning fluid to be supplied to the cleaning tank, the tray for conveying the wafers, or other conditions. Moreover, for the large wafer, since the amount of cleaning fluid for use in cleaning is also increased, the capacity of the cleaning tank is one of important factors. To solve the problems, various wafer cleaning devices and trays for use in the wafer cleaning devices have been developed.
FIG. 3
is a perspective view showing a conventional wafer cleaning device. Moreover,
FIG. 4
is a sectional view showing a section taken along line B—B in FIG.
3
.
As shown in
FIG. 3
, the conventional wafer cleaning device is constituted of a cleaning tank
50
for housing and cleaning wafers
40
conveyed by a conveyor robot
42
, and a mounting base
52
onto which the wafers
40
conveyed by the conveyor robot
42
are arranged and mounted on the bottom of the cleaning tank
50
.
When the wafer cleaning device constituted as aforementioned is used, a plurality of arranged wafers
40
are a grasped by the conveyor robot
42
in a predetermined process and conveyed to an upper part of the cleaning tank
50
. After the wafers
40
are conveyed to above the cleaning tank
50
, the conveyor robot
42
moves down to mount a plurality of wafers
40
onto the mounting base
52
of the cleantng tank
50
. After the wafers
40
are mounted, the cleaning fluid is allowed to flow via a flow port (not shown) provided in the bottom of the cleaning tank
50
, so that the wafers
40
are cleaned by the flow.
According to the wafer cleaning device constituted as described above, since the wafers
40
are constantly cleaned by the cleaning fluid when the conveyor robot
42
mounts and takes out the wafers, the wafers
40
are not contaminated by the conveyor robot
42
.
In the structure of the wafer cleaning device, however, as shown in
FIG. 4
, a space H in which the conveyor robot
42
is steeped is necessary between the side face of the wafer
40
and the side wall of the cleaning tank
50
. Therefore, as the cleaning tank is enlarged, the amount of cleaning fluid for use is also increased. Moreover, for the mounting base
52
provided on the bottom of the cleaning tank
50
, the contaminant substances peeled off the wafers
40
by cleaning are deposited to disadvantageously re-contaminate newly mounted wafers. To solve the problem, there is proposed a wafer cleaning device in which wafers are housed in a tray for cleaning.
FIG. 5
is a perspective view showing such conventional wafer cleaning device and a tray for use in the wafer cleaning device. Moreover,
FIG. 6
is a sectional view showing a section taken along line C—C shown in FIG.
5
.
As shown in
FIG. 5
, in the conventional wafer cleaning device and the tray for use in the wafer cleaning device, there are provided a tray
70
formed substantially in a box shape having opened top and bottom ends for containing inside a plurality of vertically arranged wafers
60
, and a cleaning tank
80
for cleaning the wafers
60
in the tray
70
conveyed by a conveyor robot
62
.
When the wafer cleaning device and the tray for use in the wafer cleaning device constituted as described above are used, in a predetermined process, a plurality of wafers
60
are inserted in the tray
70
, and the tray
70
is grasped and conveyed to above the cleaning tank
80
by the conveyor robot
62
. After the conveyor robot
62
conveys the wafers
60
to above the cleaning tank
80
, the conveyor robot
62
moves down to mount the tray
70
onto the bottom of the cleaning tank
80
. After the tray
70
is mounted, the cleaning fluid is allowed to flow via a flow port (not shown) provided in the bottom of the cleaning tank
80
, so that the wafers
60
are cleaned by the flow.
According to the wafer cleaning device and the tray for use in the wafer cleaning device, as shown in
FIG. 6
, a space in which the conveyor robot
62
is steeped is unnecessary between the side face of the tray
70
and the side wall of the cleaning tank
80
. By eliminating the space, the cleaning tank
80
can be miniaturized. Moreover, after cleaning is completed, the tray
70
containing the wafers
60
is removed from the cleaning tank
80
, and kept constantly in a clean state, so that the wafers
60
fail to be contaminated.
In this manner, cleaning is effectively performed by preventing the wafers from being contaminated in the conventional wafer cleaning device and the tray for use in the wafer cleaning device.
However, in the conventional wafer cleaning device and the tray for use in the wafer cleaning device, since the fluid resistance of the cleaning fluid is enlarged inside the tray
70
shown in
FIG. 5
, the flow rate of the cleaning fluid is relatively decreased in the vicinity of the wafers. Therefore, to secure a constant flow rate necessary for the cleaning of wafers, a high flow rate is necessary in whole, and the amount of cleaning fluid for use is also disadvantageously increased.
Moreover, in the conventional wafer cleaning device and the tray for use in the wafer cleaning device, a grasping portion by which the wafers are grasped has a large contact area abutting on the wafers in the tray, and a probability of contaminating the wafers by particles and other contaminant substances is high. There is a disadvantage that the particles and other contaminant substances adversely affect production yield and remarkably deteriorate product quality.
An object of the present invention is to solve the problem described above and to provide a wafer cleaning device which prevents the contamination of wafers and which can effectively clean the wafers and a tray for use in the wafer cleaning device.
DISCLOSURE OF THE INVENTION
To solve the problem described above, the present invention provides a wafer cleaning device in which a plurality of wafers arranged at predetermined intervals are housed in a cleaning tank and cleaning fluid is supplied from a bottom face to clean the wafers. There is provided a tray which comprises grasping grooves formed in a band-shaped peripheral wall surrounding an outer periphery of the plurality of arranged wafers to expose upper and lower portions of the wafers for grasping opposite side ends of the arranged wafers and grasping portions by which the peripheral wall is conveyed. There is also provided a cleaning tank which comprises a guide for holding the tray in a predetermined position, a bottom face formed conforming to a bottom-face shape of the wafer, and a flow port for allowing the cleaning fluid to flow between the bottom face and wafer bottom faces.
Here, the bottom portion of the cleaning tank is formed substantially in a V-shape conforming to the bottom-face shape of the wafer, and inclined at an angle of 24 degrees relative to a horizontal plane. Moreover, the cleaning tank is further provided, on an outer side face, with an overflow tank to which the cleaning fluid overflows. The overflow tank is further provided with a circulation means for circulating overflown cleaning fluid again into the cleaning tank to change the flo
Abe Yusuke
Ando Ei-Ichi
Hirokawa Masatoshi
Nishizaki Kazuto
Oishi Tetsuji
Gulakowski Randy
Kornakov M.
SPC Electronics
Trop Pruner & Hu P.C.
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