JPH0430417A - Semiconductor wafer retaining and rotating device - Google Patents

Abstract

PURPOSE:To reduce the adhesion of dust on the rear surface of a retained wafer by providing a notch on a vacuum suction chuck. CONSTITUTION:The sucking surface 1A of a chuck 1, with which a semiconductor wafer is retained by sucking for resist coating, developing and the like, is arranged in the vicinity of the outer circumference of the wafer 2, and the chuck 1 is provided with a notched part 20 to be used to expose a part of the rear surface of the retained wafer. A groove 6 is provided on the sucking surface 1A, and the wafer 2 is held by suction to the sucking surface 1A of the chuck 1 by the difference of pressure between the negative pressure in the groove 6 and the atmospheric air pressure. The number of dust adhered to the rear surface of the wafer can be reduced by the constitution having a small area of sucking surface on the above-mentioned chuck. Also, when the chuck is positioned and stopped by the notch of a disc, which is integrally rotated, and the chuck, the wafer can be carried in and out easily by a wafer handling device.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a semiconductor wafer holding and rotating device such as a photoresist rotation coating and development processing device for semiconductor wafers, and in particular, a device for holding and holding a wafer by vacuum suction chuck. The invention relates to a device that rotates the device.

[Conventional technology]

Conventionally, as a wafer holding and rotating device for resist coating, developing equipment, etc., as disclosed in Japanese Utility Model Application Publication No. 63-33631, for example, a vacuum suction chuck that holds a wafer has a vacuum suction chuck that holds a wafer at the center of the surface facing the held wafer. There are four parts that escape contact with the wafer, and around these recesses, there is an annular suction surface that has an outer shape that matches the outer shape of the wafer.

[Problem to be solved by the invention]

In order to realize the future submicron process for semiconductor book manufacturing, it is necessary to maintain the backside of the wafer as clean as the front side, and to reduce the amount of foreign matter adhering to the backside of the wafer, it is necessary to maintain the cleanliness between the wafer and various equipment. Measures are being taken to reduce the area of contact. However, in wafer holding and rotation devices for resist coating, developing devices, etc., it is necessary to transmit large rotational torque to the held wafer, so a vacuum suction chuck with a large wafer suction surface is required. It is unavoidable that a large amount of dust adheres to the back surface, and there is a strong desire to make the wafer holding and rotation device clean, which is a serious problem that must be solved as soon as possible.

In response to this requirement, in the conventional technology, the wafer suction surface of the vacuum suction chuck is provided closer to the outer circumference of the wafer, so it is possible to transmit a predetermined rotational torque to the wafer with a smaller suction surface area than before. Therefore, it is possible to reduce foreign matter adhering to the backside of the wafer, but since the vacuum chuck is structured to cover the entire backside of the wafer,
There has been a problem in that the wafer cannot be carried into the vacuum chuck or carried out from the vacuum chuck using a handling device that suction-holds or supports the back surface of the wafer.

In addition, since the vacuum suction chuck is not equipped with a rotational positioning mechanism, it is not possible to position the vacuum suction chuck at a predetermined position and stop it. There is a problem in that it is impossible to suction the wafer with the orientation flat portion aligned with the suction surface. Furthermore, since the suction surface is provided in an annular shape surrounding the recess, and the annular suction surface is provided with an annular groove through which negative pressure is introduced, the pressure inside the recess becomes negative pressure, and the held wafer is moved into the recess. There was a problem that it could be drawn in and deformed.

An object of the present invention is to reduce the adhesion of dust to the back surface of the held wafer by sucking and holding the wafer with a small suction surface area in order to prevent dust from adhering to the back surface of the held wafer. An object of the present invention is to provide a semiconductor wafer holding/rotating device which allows a wafer to be carried in and carried out by a wafer handling device that suctions or supports the wafer, and which does not cause deformation of the held wafer.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a vacuum suction chuck for suctioning and holding a wafer, and a rotation mechanism for rotating the chuck, in a wafer holding and rotating device such as a resist coating and developing device that suctions and holds a semiconductor wafer and rotates the chuck. and a rotational positioning mechanism for positioning and stopping the chuck at a predetermined position, and the vacuum suction chuck is provided with one or more suction surfaces, and the suction surface is configured to suction the outer peripheral portion of the wafer back surface. The vacuum suction chuck, which is disposed nearby, has a notch or a window for exposing a part of the back surface of the held wafer to the outside.

[Effect]

A vacuum suction chuck attracts and holds a wafer on the chuck using the suction force of vacuum. The rotation mechanism rotates the vacuum suction chuck together with the holding wafer. The rotary positioning mechanism positions and stops the vacuum suction chuck at a predetermined position. The suction surface of the vacuum suction chuck is placed near the outer periphery of the wafer, so the suction surface area is smaller than that of a conventional vacuum suction chuck, in which the suction surface is placed near the center of rotation of the chuck. Torque can be transmitted to the wafer. Since the suction surface area is small, the number of dust particles adhering to the back surface of the held wafer is reduced compared to conventional devices. In addition, the vacuum suction chuck is equipped with a notch or a window to expose a part of the backside of the held wafer to the outside, so the exposed backside of the wafer can be used to suction and hold the wafer backside. The wafer can be loaded into and unloaded from the vacuum suction chuck by a supporting handling device. At this time, since the vacuum suction chuck is positioned and stopped at a predetermined position by the rotation positioning mechanism, it is possible to prevent interference between the vacuum suction chuck and the handling device that carries the wafer into and out of the vacuum suction chuck.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 to 8 show an embodiment of the apparatus of the present invention.

In these figures, 2 indicates, for example, a semiconductor wafer to be held by suction. The apparatus includes a chuck 1 that holds the wafer 2 by vacuum suction, a rotation mechanism 3 such as a motor that rotates the chuck, and a rotation positioning mechanism 4 such as a rotary encoder that positions and stops the chuck 1 at a predetermined position. There is. The chuck 1 is provided with a suction surface IA that suctions the back surface of the wafer 2.
is arranged near the outer part of the wafer so as to attract the outer peripheral part of the back surface of the wafer 2. As shown in FIGS. 1 to 8, a groove 6 is provided in the suction surface IA, and a gas suction hole 8 for sucking gas in the groove is opened in the groove. In this case, two suction surfaces IA are provided,
The groove 6 of the two suction surfaces 1A connects the two suction surfaces IA,
They are connected by a communication groove 7 provided on a communication surface IB that is on the same plane as the suction surface, and - number of gas suction holes 8 are connected to the grooves 6 of the two suction surfaces IA connected by this communication groove 7. It is provided. The chuck 1 is provided with an exposed portion for exposing a part of the back surface of the held wafer 2 to the outside, and in this case, the exposed portion is formed by a notch 20.

Next, its operation will be explained.

2 and 3, when the gas in the groove 6 is sucked from the gas suction hole 8 with the wafer 2 in contact with the suction surface IA of the chuck 1, the inside of the groove 6 whose upper surface is closed by the wafer 2 is The pressure becomes less than atmospheric pressure, and the wafer 2 is held by suction on the suction surface IA of the chuck 1 due to the differential pressure between the negative pressure in the groove 6 and the atmospheric pressure. In this state, when a rotating mechanism such as a motor shown in FIG. 1 is operated, the wafer 2 is moved to the chuck 1.
At this time, in a wafer holding/rotating device for a resist coating, developing device, etc., the chuck 1 holding the wafer 2 starts rotating very steeply. For example, in the resist coating sequence, the rotation speed is 1500 rpm for 0.03 seconds.
Accelerated from 450 rpm.

That is, a rotation start-up operation is performed that reaches the original rpm/see in terms of acceleration. In order to achieve this rotational acceleration, the chuck 1 is provided with a large-area suction surface IA, thereby transmitting a predetermined rotational torque to the wafer 2. The rotational force a speed to be achieved is (d2ft/d t
2) If the moment of inertia of the wafer 2 is T, the transmission rotational torque to be transmitted from the chuck 1 to the wafer 2 through the suction surface IA is T, and the area of the suction surface IA is S, then T=μp far d a − (1
)S = f ad a
−(2)T〉 ■ (d2θ /dt 2)
... (3) where μ: coefficient of friction between the suction surface IA and the wafer 2 p: differential pressure between atmospheric pressure and negative pressure in the groove 6 a: suction surface area (effective part) be done.

From Equations (1) and (2), - As an example, when comparing the chuck suction surface area of the conventional device and the device of the present invention for the chuck of a resist coating device for 8-inch wafers, the following is obtained. That's right.

<Conventional device> Adsorption surface shape: circular with radius ro = 40on+ Transmission torque:
Tp =2/3πμpro3=134. Oμpkg'
Button suction surface area: Sp = x ro2 = 50.3ci One embodiment of the present invention> Suction surface shape: outer radius r2 = 90nwn + inner radius rr
= 85 n An annular fan-shaped area with a central angle α of 2100 degrees transmits torque on two surfaces: Tn = 2/3 x μp (rz3- rx')X
2 α/360= 133.7μpkg-cm Adsorption surface intoxication product: 5n=x(r22-rz2)X2α/360=15.3
cn (As shown here, the suction surface IA of the vacuum suction chuck 1 is arranged near the outer periphery of the wafer 2.
A predetermined rotational torque can be transmitted to the wafer 2 with a small suction surface area of about 0%.

In the case of a vacuum suction chuck, the number of foreign particles adhering to the back surface of the wafer is proportional to the area of the suction surface, so by reducing the suction area to 30%, the number of dust particles adhering to the back surface of wafer 2 is also reduced to about 30% of that of conventional equipment. do.

Further, the cut portion 30 of the chuck 1 exposes a part of the back surface of the held wafer 2 to the outside when the wafer 2 is held by suction. The loading and unloading of the wafer 2 into and out of the chuck 1 normally uses a wafer handling device that holds and supports the back side of the wafer, but since the chuck 1 is equipped with a notch 20, it can hold the back side of the wafer. ,or,
Supportive handling equipment can be used. At this time, when the chuck 1 stops, the rotational positioning mechanism 4 positions the rotational position of the chuck 1 at a predetermined position and stops the chuck 1. As a result, the stop position of the notch 2o of the chuck 1 is determined, and interference between the chuck 1 and the handling device for loading and unloading is prevented.

In addition, in the case of this device, the chuck 1 can be positioned and stopped, so when loading the wafer into the chuck 1, by determining the position of the orientation flat in advance, the resist coating chuck 1, the developing device chuck 1
Even if the wafer 2 is held by suction on multiple chucks 1,
Since the same area of the back surface of the wafer 2 is always held by the suction surface, the amount of dust adhering to the back surface of the wafer 2 can be reduced.

Further, FIGS. 9 and 10 show other configuration examples of the rotational positioning mechanism 4. Instead of the rotary encoder, a disc with a notch 10 is attached to the chuck 1 or the rotating shaft 5 of the rotating mechanism 3 such as a motor, and the light projecting section 12 is inserted with this disc in between. A photosensor 11 having a light receiving section 13 is installed.

By sensing the notch portion with the photosensor 11 and stopping the chuck 1 in response to this signal, the position of the chuck 1 can be determined and stopped.

11 and 12 show another embodiment of the device of the invention. In this embodiment, the gas suction hole 8 communicates with the groove 6 through a communication pipe 15 provided inside the structure of the chuck 1, and the two suction surfaces IA are separately provided only near the outer periphery of the Uni-No. It is.

According to this embodiment, since there is no suction surface near the center of the rotation axis where transmission torque is small, the wafer 2 can maintain a predetermined rotational torque with an even smaller suction surface area compared to the first example. can be transmitted.

FIGS. 13 and 14 show still another embodiment of the apparatus of the present invention. In this embodiment, a window portion 21 is provided in place of the notch portion 20 provided to expose a part of the back surface of the wafer 2 held by the chuck 1 to the outside, and the suction surface IA is provided entirely near the outer periphery of the wafer 2. This is the case where it is provided all around the circumference.

According to this embodiment, since the suction surface IA is provided along the entire circumference of the wafer 2, a predetermined rotation can be achieved with a smaller suction surface area compared to the first embodiment. Torque can be transmitted to the wafer 2.

At this time, the outer diameter of the suction surface 1A is formed smaller than the outer diameter of the wafer 2, so that it can hold the back surface of the wafer 2 or
A supporting loading/unloading wafer handling device holds or supports the back side of the wafer 2 outside the chuck 1.

〔Effect of the invention〕

According to the present invention, since the suction surface area of the chuck required to transmit a predetermined rotational torque to the held wafer is small, the number of dust particles adhering to the back surface of the held wafer can be reduced. Furthermore, since the chuck can be positioned and stopped, the wafer can be loaded into and taken out of the chuck using a wafer handling device that holds or supports the backside of the wafer.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the apparatus of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a vertical front view thereof, FIG. 4 is a vertical front view thereof, and FIGS. 7 and 8 are partial vertical cross-sectional views showing the vicinity of the gas suction hole. FIG. 9 is a plan view showing another embodiment of the rotary positioning mechanism. Figure 10 is its front view, 1st
1 is a plan view showing another embodiment of the device of the present invention;
13 is a plan view showing still another embodiment of the apparatus of the present invention, and FIG. 14 is a longitudinal sectional front view thereof. DESCRIPTION OF SYMBOLS 1...Chuck, IA...Adsorption surface, 2...Wafer, 3...Rotation mechanism, 4 Rotation positioning mechanism, 6...Groove, 8...Gas suction hole, 15...Communication pipe line , 20...
Notch part, 21...window part. Agent: Patent attorney Katsuo Ogawa. 〈茅■ ' −−−+t,, 7 irq −−−−o>, 1 side Z−−−Wafer 5−1−−Roki isosin'@−−1−[El 啼i, i rainbow , j [n big 8 +
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Claims (1)

[Scope of Claims] 1. A wafer holding and rotating device including a resist coating and developing device that holds and rotates a semiconductor wafer by suction, comprising: a vacuum suction chuck that suctions and holds the wafer; a rotation mechanism that rotates the chuck; a rotational positioning mechanism for positioning and stopping the chuck at a predetermined position, the vacuum suction chuck having one or more suction surfaces,
The suction surface is arranged near the outer circumference of the wafer so as to suction the outer circumference of the back surface of the wafer, and the vacuum suction chuck exposes a part of the back surface of the held wafer to the outside. A semiconductor wafer holding/rotating device characterized by comprising an exposed portion, a notch portion, or a window portion for the purpose of holding and rotating a semiconductor wafer.