Brushing – scrubbing – and general cleaning – Machines – Brushing
Reexamination Certificate
2001-11-06
2004-10-26
Chin, Randall (Department: 1744)
Brushing, scrubbing, and general cleaning
Machines
Brushing
C015S088200, C015S102000, C134S183000
Reexamination Certificate
active
06807701
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method of cleaning abrasive plates of an abrasive machine and a cleaning device, more precisely relates to a method, in which abrasive faces of an upper abrasive plates and a lower abrasive plates, which are mutually faced and rotated, are cleaned by water jetted from a nozzle moving along the abrasive faces, and a cleaning device executing said method.
Both side faces of a wafer-shaped work piece, e.g., silicon wafer, are abraded by an abrasive machine. A lapping machine, which is a kind of abrasive machines, is shown in FIG.
10
.
In
FIG. 10
, the lapping machine has an upper abrasive plate
20
, whose lower face is an abrasive face for lapping work pieces
10
, e.g., silicon wafers, and keys
21
are keyed in an upper face of the upper abrasive plate
20
. An air cylinder unit
22
is provided above the upper abrasive plate
20
. The air cylinder unit
22
is fixed to an upper part of a gate-shaped frame
14
. The upper abrasive plate
20
is rotatably connected to a lower end of a piston rod
22
a
of the air cylinder unit
22
by a rotary plate
23
and connecting rods
27
. By employing a connector
22
b
, the piston rod
22
a
cannot rotate; the rotary plate
23
and the upper abrasive plate
20
, which are connected by the connecting rods
27
, can be rotated with respect to the piston rod
22
a
and held at the lower end thereof. With this structure, weight or a pressing force of the upper abrasive plate
20
, which works to a lower abrasive plate
30
, can be controlled by adjusting a lifting force of the cylinder unit
22
.
Note that, in some cases, the pressing force working to the lower abrasive plate
30
is controlled by adjusting a pressing force applied to the upper abrasive plate
20
.
Since the keys
21
engage with key grooves of a rotary member
54
which is rotated by a motor
70
, the upper abrasive plate
20
is rotated by a driving force of the motor
70
. A shaft
54
a
is downwardly extended from the rotary member
54
. A gear
54
b
, which is fixed to a lower end of the shaft
54
a
, is engaged with an idle gear
63
, and the idle gear
63
is engaged with a gear
64
, which is fixed to a spindle
60
. With this structure, the driving force or torque of the motor
70
can be transmitted to the upper abrasive plate
20
via the rotary member
54
.
Since the upper abrasive plate
20
and the rotary member
54
are connected by the keys
21
, a clearance between the upper abrasive plate
20
and the lower abrasive plate
30
can be made wider by actuating the air cylinder unit
22
when the work pieces
10
are set or discharged or maintenance is executed.
Carriers
40
are rotated by an external gear
50
and an internal gear
52
. A first hollow shaft
50
a
, which is coaxial to the shaft
54
a
, is connected to the external gear
50
, and a gear
50
b
, which is fixed to the first hollow shaft
50
a
, is engaged with a gear
65
of the spindle
60
.
A second hollow shaft
30
a
, which is coaxial to the first hollow shaft
50
a
, is connected to the lower abrasive plate
30
, and a gear
30
b
, which is fixed to a mid part of the second hollow shaft
30
a
, is engaged with a gear
61
of the spindle
60
.
A third hollow shaft
52
a
, which is coaxial to the second hollow shaft
30
a
, is connected to the internal gear
52
, and a gear
52
b
, which is fixed to the third hollow shaft
52
a
, is engaged with a gear
62
of the spindle
60
. The spindle
60
is connected to an adjustable reduction unit
69
, which is connected to the motor
70
, e.g., an electric motor, a hydraulic motor, by a belt.
The upper abrasive plate
20
, the lower abrasive plate
30
, the external gear
50
and the internal gear
52
are rotated by one motor
70
via the reduction unit
69
, the gears and the shafts.
An upper abrasive face of the lower abrasive plate
30
has discharging grooves
12
and
16
, which run like lattice as shown in
FIG. 11
, so as to discharge abraded dusts, which are produced by abrading the work pieces
10
, and slurry from the abrasive face. The discharging grooves
12
and
16
are formed in the lower abrasive face of the upper abrasive plate
20
, too.
The abraded dusts and slurry gradually deposit in the discharging grooves
12
and
16
, and they damage surfaces of the work pieces
10
. To prevent the damage of the work pieces
10
, the clearance between the abrasive plates
20
and
30
is widen by actuating the air cylinder unit
22
after a prescribed number of abrasive works are completed so as to clean the abrasive faces of the abrasive plates
20
and
30
.
However, the abraded dusts and slurry are solidified in the grooves
12
and
16
of the abrasive faces of the abrasive plates
20
and
30
, so they must be manually removed. Namely, a metal plate is manually inserted into the grooves
12
and
16
so as to scrape out the solidified dusts from the grooves
12
and
16
. It takes a long time to completely clean the abrasive faces, and the abrasive faces are sometimes damaged.
To automatically clean the abrasive faces, a cleaning device was disclosed in the Japanese Patent Gazette No. 7-9342 (see FIG.
12
). In the conventional cleaning device shown in
FIG. 12
, front end sections of two nozzles
100
a
and
100
b
are respectively enclosed by brush members
102
. The nozzles
100
a
and
100
b
are provided to a front end of a shaft
106
and respectively headed upward and downward. With this structure, pressurized water is jetted upward and downward from the nozzles
100
a
and
100
b
. The shaft
106
is vertically and horizontally moved together with the nozzles
100
a
and
100
b.
In the cleaning device shown in
FIG. 12
, front ends of the brush members
102
simultaneously contact the abrasive faces of the upper abrasive plate
20
and the lower abrasive plate
30
, and the pressurized water, whose pressure is about 50-100 atm., is simultaneously jetted from the nozzles
100
a
and
100
b
toward the abrasive faces rotating (see FIG.
13
). The nozzles
100
a
and
100
b
are moved in the radial direction with respect to the abrasive faces, so that abraded dusts deposited in the grooves
12
and
16
of the abrasive faces can be removed.
The cleaning device shown in
FIGS. 12 and 13
can automatically clean the abrasive faces of the abrasive plates
20
and
30
.
When the pressurized water is jetted from the nozzles
100
a
and
100
b
toward the abrasive faces, the nozzles
100
a
and
100
b
are respectively formed by the brush members
102
and the abrasive faces, so that the jetted water cannot be scattered outside.
However, outer edges of the abrasive plates
20
and
30
must be washed so as to clean the whole abrasive faces. When the nozzles
100
a
and
100
b
are moved to the outer edged of the abrasive plates
20
and
30
, gaps are respectively formed between the outer edges of the abrasive plates
20
and
30
and the brush members
102
as shown in
FIG. 14
, so that the jetted water is scattered outside from the gaps.
The water jetted outside from the gap between the outer edge of the lower abrasive plate
30
and the brush member
102
for cleaning the lower abrasive plate
30
is received and introduced outside of the cleaning device via a discharging section
31
a
(see FIG.
10
). The discharging section
31
a
is formed along the outer edge of the lower abrasive plate
30
. As shown in
FIG. 10
, the internal gear
52
is provided in the discharging section
31
a
, so a width of the discharging section
31
a
is narrow. Therefore, the water, which has once passed through the discharging section
31
a
, is not returned to the abrasive face via the discharging section
31
a.
On the other hand, the water jetted outside from the gap between the outer edge of the upper abrasive plate
20
and the brush member
102
for cleaning the upper abrasive plate
20
is scattered into a space, in which an abrading mechanism is set.
The water, which is scattered into the space, includes the abraded dusts and used slurry, so it makes abraded products dirty.
Denda Yasuhide
Hasegawa Tsuyoshi
Moriya Norihiko
Nakajima Makoto
Nakamura Yoshio
Chin Randall
Fujikoshi Machinery Corp.
Jordan and Hamburg LLP
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