Method of sticking semiconductor wafer and its sticking device

A method of sticking a semiconductor wafer and its sticking equipment. The semiconductor wafer can be flat and efficiently stuck on a plate. The semiconductor wafer, which has its inner surface coated with an adhesive, is tiltedly configured to permit raising a circumference to a height of Ah and located the wafer above a sticking position on the plate. The semiconductor wafer is pressed by a lower end of a stamp-press to be parallel to a surface of the plate. Then a vacuum chuck (2) stops sucking to release the semiconductor wafer from a transporting arm, and the transporting arm is moved away. The stamp-press is moved downward to press a whole surface of the semiconductor wafer.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a method of sticking a semiconductor wafer 
on a plate which is used to polish the semiconductor wafer, and its 
sticking equipment. 
2. Description of Prior Art 
To polish a semiconductor wafer, a prior-art method which sticks the 
semiconductor wafer on a plate by an adhesive comprises the steps as 
described below: 
(1) referring to FIG. 5(a), transporting the semiconductor wafer 10 to a 
position above a sticking position on the plate 4 by a transporting 
equipment (not shown) having a prepress hand 5; 
(2) referring to FIG. 5(b), putting the semiconductor wafer 10 on the plate 
4 by the prepress hand 5, and providing at a pickup position a next 
semiconductor wafer 10b to be stuck at the same time; 
(3) referring to FIG. 5(c), rotating the turntable 6 to transport the 
semiconductor wafer 10 put on the plate 4 to a position to be pressed, and 
then rotating the prepress hand 5 to pick up the next semiconductor wafer 
10b to be stuck; 
(4) referring to FIG. 5(d), sticking the semiconductor wafer 10 on the 
plate 4 through the pressing of the stamp-press 3, and rotating the 
prepress hand 5 to transport the semiconductor wafer 10b to the position 
above the sticking position on the plate 4. 
Next, the movements of the prepress 5 hand are described below. 
As shown in FIG. 6(a), the prepress hand 5 comprises a transporting arm 51; 
a vacuum chuck 52, which has a reversed-cup shape and is located at the 
front end of the transporting arm 51, for sucking the semiconductor wafer 
10; and a lip 53, which is able to extend and withdraw, located at the 
center of the vacuum chuck 52. 
The process of putting a semiconductor wafer 10 on the plate 4 by the 
prepress hand 5 comprises the steps of: as shown in FIG. 6(a), 
transporting the semiconductor wafer 10, which has its inner surface 
previously coated with the adhesive 11, to a position above the plate 4; 
then extending the lip 53 downward to press the semiconductor wafer 10, as 
shown in FIG. 6(b), and releasing the sucking of the vacuum chuck 52 at 
the same time, so that the semiconductor wafer 10 is put on the plate 4 
and temporarily stuck at the center thereof. Thereafter, as shown in FIG. 
5(d), complete sticking of the semiconductor wafer 10 being temporarily 
stuck is effected by the pressing of the stamp-press 3. 
However, in the sticking process mentioned above, referring to FIG. 6(b), 
the semiconductor wafer 10, while being pressed to be temporarily stuck by 
the lip 53, has its center attached on the plate 4 prior to its 
circumference in the condition of having a slightly curved shape. The 
adhesive 11 used to temporarily adhere the circumference 11a becomes 
hardened during the period of rotating the plate 4 to the position where 
the semiconductor wafer 10 is to be pressed. This temporarily stuck 
circumference 11a tends to be slightly protruded due to the mix of air and 
surface tension. As shown in FIG. 6(c), since the temporarily stuck 
circumference 11a is protruded, a ring-shaped protrusion 10c is formed on 
the surface of the semiconductor wafer 10, and the adhesive 11 is hardened 
while the semiconductor wafer 10 remains in such a shape. Therefore, the 
semiconductor wafer 10 can not be flat polished due to the protrusion 10c 
even though the semiconductor wafer is pressed by the stamp-press 3. 
Furthermore, the operating efficiency is unfavorable since operation for 
putting and operation for pressing the semiconductor wafer requires two 
separate operating movements. 
SUMMARY OF THE INVENTION 
Accordingly, to solve the above problems associated with the prior arts, an 
object of the present invention is to provide a method of sticking a 
semiconductor wafer and its sticking equipment, which can flat and 
efficiently stick the semiconductor wafer on a plate. 
The method of sticking a semiconductor wafer according to the present 
invention is given here, which moves the semiconductor wafer to a position 
above a sticking position on the plate by a transporting arm used to suck 
the semiconductor wafer, and sticks the semiconductor wafer to the plate 
by pressing the semiconductor wafer by a stamp-press, wherein the 
semiconductor wafer is configured to be tilted so as to permit a front end 
of the transporting arm having a higher circumference thereof while the 
semiconductor wafer is transported to a position above the sticking 
position on the plate, the semiconductor wafer is then put on the plate by 
releasing a sucking of the transporting arm at the time when the 
semiconductor wafer is substantially parallel to the surface of the plate 
through the pressing of a stamp-press, thereafter the transporting arm is 
moved away, and the semiconductor wafer is depressed by the stamp-press. 
Moreover, according to the present invention, the equipment for sticking a 
semiconductor wafer comprises a transporting arm which is provided with a 
vacuum chuck to suck the semiconductor wafer; and a stamp-press, which is 
elastic and substantially hemispherical, being able to press a whole 
surface of the semiconductor wafer; wherein the vacuum chuck is formed to 
support at least two points which are located at opposite positions 
corresponding to a substantial center of the semiconductor wafer and 
positioned on a circumference of the surface of the semiconductor wafer, 
wherein a width between the points permits at least a lower end of the 
stamp-press to insert therein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Embodiment 1 
Referring to FIG. 2, the sticking equipment of the first embodiment 
comprises: a transporting arm 1 for transporting a semiconductor wafer 10; 
and a stamp-press 3 for pressing the surface of the semiconductor wafer 
10. 
Referring to FIG. 3, the transporting arm 1 includes a vacuum chuck 2, 
which is substantially U-shaped and located at the front end thereof, for 
sucking the surface of the semiconductor wafer 10. A sucking groove 21, 
which is formed along the circumference of the semiconductor wafer 10 and 
has a substantially semicircular shape, is provided on the vacuum chuck 2, 
the semiconductor wafer 10 is thereby sucked by the sucking groove 21. 
Referring to FIG. 2, the stamp-press 3 is substantially hemispherical. 
Since the stamp-press is elastic, the deformed surface being pressed is 
gradually enlarged while the lower end 31 of the stamp-press starts 
contacting the surface of the semiconductor wafer 10. The whole surface of 
the semiconductor wafer 10 is thus able to be uniformly pressed. 
Referring to FIG. 3, the two front ends 22, 23 of the vacuum chuck 2 are 
located at the opposite positions corresponding to the substantial center 
of the semiconductor wafer 10. As shown in FIG. 2, the width between the 
two front ends 22, 23 permits the lower end 31 of the stamp-press 3 to 
insert therein. 
Next, the sticking method of a semiconductor wafer of the present invention 
utilizing the sticking equipment of the first embodiment is described. 
Referring to FIG. 1(a), being sucked by the vacuum chuck 2 of the 
transporting arm 1, the semiconductor wafer 10, which has its inner 
surface coated with the adhesive 11, can be transported. At this time, the 
transporting arm 1 is transported to a position above a sticking position 
on the plate 4 by means of the servo-motor 12 at the equipping part, 
having its front end slightly lifted. Therefore, the semiconductor wafer 
10 is configured to be tilted to permit the circumference 10a of the front 
end of the transporting arm 1 to be raised to a height of .DELTA.h. 
The magnitude of .DELTA.h is varied with different diameters of the 
semiconductor wafer 10, i.e., about 1 mm for 200 mm wafer. 
Referring to FIG. 1b, the stamp-press 3 is moved down to make its lower end 
31 contact to the central surface of the semiconductor wafer 10, so that 
the semiconductor wafer 10 is pressed. Further, the both front ends 22, 23 
of the vacuum chuck 2 are pressed to lower the circumference 10a of the 
semiconductor wafer 10. 
Referring to FIG. 1(c), at the time when the semiconductor wafer 10 is 
substantially parallel to and touching the surface of the plate 4, the 
vacuum chuck 2 stops sucking the semiconductor wafer 10, so that the 
transporting arm 1 releases the semiconductor wafer 10 and is then moved 
away. As a result, the semiconductor wafer 10 can be put flat on the 
surface of the plate 4. 
Referring to FIG. 1(c), the stamp-press 3 is moved down more to press the 
whole surface of the semiconductor wafer 10, so that the semiconductor 
wafer 10 is simultaneously stuck on the plate 4 through the putting and 
pressing movements. The semiconductor wafer 10 can be pressed continuously 
from the center to the circumference by the stamp-press 3. Thereby, the 
air between the adhesive 11 and the plate 4 can be pushed out at a 
stretch, and the whole semiconductor wafer 10 can be uniformly pressed. 
This method prevents only a part of the adhesive 11 hardening first, or 
having the adhesive 11 harden by mixing with air. 
Embodiment 2 
FIG. 4 is a partial plane diagram illustrating the transporting arm of the 
second embodiment. 
In embodiment 1, the vacuum chuck 2 is substantially U-shaped, the sucking 
groove 21 is formed, but not limited, to a substantially semicircular 
shape. The adherence of a semiconductor wafer in accordance with the 
sticking method of the present invention can be accomplished, only if at 
least two points, which are located at the circumference and at the 
opposite positions corresponding to a substantial center of the 
semiconductor wafer, are positively supported. 
Further, as shown in FIG. 4, the transporting arm 1a of the second 
embodiment has the vacuum chuck 2a at its front end substantially formed 
in a two-prong fork shaped. Sucking forth 21a, 21b, 21c are respectively 
set up at the two front ends and the middle, and configured as an 
isosceles triangle. 
Due to the constitution mentioned above in the present invention, the 
surface of a semiconductor wafer can be pressed continuously from the 
center to the circumference at a stretch by a stamp-press. This prevents 
only a part of the adhesive hardening first, or having the adhesive harden 
by mixing with air. 
Moreover, since the semiconductor wafer can be simultaneously stuck through 
the putting and pressing movements, the efficiency of sticking a 
semiconductor wafer to the plate is remarkably improved in comparison with 
the prior-art method.