Metal working – Barrier layer or semiconductor device making
Reexamination Certificate
1998-09-17
2001-02-13
Niebling, John F. (Department: 2812)
Metal working
Barrier layer or semiconductor device making
C134S902000, C414S935000, C414S940000
Reexamination Certificate
active
06187060
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a processing apparatus for and a processing method of executing a treatment including a process in which an object to be processed, such as a semiconductor wafer, is rotated so as to scatter liquid sticking on a surface of the object by centrifugal force due to its rotation.
For example, in the manufacturing process for a semiconductor device, various cleaning systems are employed for removing contamination, such as particles and organic contaminants, on the surface of the semiconductor wafer. Note, the semiconductor wafer will be referred as “the wafer”, hereinafter. Above all, a cleaning system of the wet type where the water can be cleaned by dipping it into cleaning liquid in a processor has merit to remove the particles on the wafer effectively.
In order to permit a continuous batch process, the wet type cleaning system comprises a loader for loading, for example, twenty five wafers into the processing apparatus with every carrier, transporting means for transporting fifty wafers corresponding to two carriers loaded by the loader collectively, a processing unit arranged for cleaning and drying the wafers, which have been transported by the transporting means, in batch processing, and an unloader for unloading the wafers cleaned and dried. With these elements, this cleaning system is called “a wet station” in widespread use.
At respective processing sections constituting the wet station, a variety of chemical treatments, such as ammonia treatment, hydrogen fluoride treatment, sulfuric acid treatment, hydrochloric acid treatment etc., and a washing treatment with pure water are carried out by turns. Further, a drying treatment is executed finally.
As the processing section for drying the waters, there are well-known a rotary processing part in which the wafers are dried by shaking treatment-liquid off wafer surfaces due to the action of centrifugal force caused by rotating the wafers, and a IPA processing part in which the wafers are dried by draining while supplying water-amiable IPA [isopropyl alcohol: (CH
3
)
2
CHOH] steam to the wafer surfaces, conventionally. The rotary processing part which is also called “spin dryer” has the advantage of simple structure and low running costs because of disuse of an explosion-proof mechanism, in comparison with those of the IPA processing part. In the prior art, a spin dryer disclosed in e.g. Japanese Utility Model Publication (kokai) No. 5-83870 is well-known as the rotary processing (drying) part.
We now describe a structure of the conventional rotary drying part in brief. As shown in
FIG. 1
, a processing chamber
200
arranged in the rotary processing part includes a pair of rotating shafts
201
,
202
arranged in serice. The rotating shaft
201
is one to which rotating force of a motor
203
is transmitted, while the other shaft
202
is a driven shaft. To the rotating shafts
201
,
202
, rotors
205
,
206
in processing chamber
200
are attached respectively. A plurality of wafers W are collectively carried in their juxtaposed condition by constraint mechanisms
207
,
208
bridging between the rotor
205
and the rotor
206
. As shown in
FIG. 2
, the constraint mechanisms
207
,
208
are provided, on surfaces thereof abutting on the wafers W, with numerous grooves
210
which are formed at constant intervals. In use, by inserting the peripheries of the wafers W into the groove
210
, it is possible to carry the plural wafers W between the constraint mechanisms
207
,
208
while keeping the wafers W to be juxtaposed apart from each other at regular intervals.
Further, against the processing chamber
200
, not-shown intake port and exhaust port are connected for flowing air in the chamber
200
. Since the wafers W are rotated while ventilating the chamber
200
through the intake and exhaust ports, it is possible to scatter moisture sticking on the wafers W by centrifugal force and also to dry the wafers W per se by the flowing of fresh air.
In such a rotary processing part, however, there is a case that the center or gravity of the wafers W and the center of rotation (of the rotating shafts
201
,
202
) do not overlap with each other. If the wafers W are rotated while leaving such a condition, vibrations may be caused during its rotation because of the ill-balanced rotary processing part. Therefore, from the points of view of the prevention of noise and the improvement in durability of the apparatus, it is necessary to adjust the balance of the rotary processing part so as not to increase vibrations caused by the rotation of the wafers W, thereby suppressing centrifugal whirling of the shafts. For this purpose, in the above processing part, two autobalancers
211
,
212
are mounted on the rotating shafts
201
,
202
rotating together with the wafers W respectively, for their integral rotation. In detail, the adjustment of balance is executed by moving counterweights accommodated in the autobalancers
211
,
212
to appropriate positions.
It should be noted that the autobalancers
211
,
212
have similar structures to each other. Therefore, we now describe the structure of autobalancer
211
mounted on the shaft
201
representatively. As shown in
FIGS. 3A and 3B
, the autobalancer
211
is provided with a pair of inside counterweights
213
,
214
. Since the counterweights
213
,
214
rotate together with the shaft
201
, centrifugal forces
215
,
216
are applied on the counterweights
213
,
214
, respectively. In arrangement, the counterweights
213
,
214
can be angularly moved freely within 360 degrees. In this regard,
FIG. 3A
shows a condition that the counterweight
213
is diametrically opposite to the counterweight
214
(at 180 degrees). In this case, a direction of centrifugal force
215
applied on the counterweight
213
is opposite to that of centrifugal force
216
applied on the counterweight
214
, a resultant force of the centrifugal forces
215
,
216
amounts to zero by their mutual negation.
While,
FIG. 3B
shows a condition that the counterweights
213
,
214
are angularly moved from the positions of
FIG. 3A
by predetermined angles. In this case, the autobalancer
211
during rotation is subjected to a resultant force
217
consisting of the centrifugal force
215
applied on the counterweight
213
and the centrifugal force
216
applied on the counterweight
214
. In this way, by optionally changing the positions of the counterweights
213
,
214
in the autobalancers
211
,
212
, it is possible to change both direction and magnitude of the resultant force
217
consisting of the centrifugal force
215
applied on the counterweight
213
and the centrifugal force
216
applied on the counterweight
214
. Thus, with the optional establishment in direction and magnitude of the resultant force
217
, the balance of the wafers W rotating in the processing chamber
200
is adjusted in the conventional processing part. Note, as mentioned above, the autobalancer
212
has a structure similar to that of the autobalancer
211
.
Now, as a method of seeking the most suitable positions of the counterweight
213
,
214
in the autobalancer
211
,
212
for adjusting the balance, the following method has been generally adopted conventionally. That is, in order to examine a relationship between the positions of the counterweights
213
,
214
and vibratory values, it is executed at least once to rotate the wafers W and measure their vibrations while successively changing the positions of counterweights
213
,
214
by e.g. five degrees (5°) at a time on condition that the wafers W are accommodated in the processing chamber
200
of the rotary processing part previously. In this way, the most suitable positions of the counterweights
213
,
214
to reduce the vibrations the most are determined on the basis of the obtained relationship.
However, it is impossible to seek the most suitable positions of the counterweights
213
,
214
unless accommodating the wafers W in the processing chamber
200
and rotating them practically.
Miyachi Kenji
Nishida Tatsuya
Oka Syujiro
Niebling John F.
Smith , Gambrell & Russell, LLP
Stevenson André C
Tokyo Electron Limited
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