JPH11233588A - Wafer conveyor and wafer conveying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance conveying efficiency of a wafer conveyor and enhance process efficiency of a wafer processor, by a method wherein a conveying step of supplying unprocessed wafers to the wafer processor and a conveying step of withdrawing processed wafers from the wafer processor are integrated. SOLUTION: In a wafer conveyor containing a robot arm 2 and a wafer lifting mechanism 3 provided in a susceptor 1, the robot arm 2 has upper and lower twostage fingers 2A, 2B for supporting wafers W1, W2, and the wafer lifting mechanism 3 has a plurality of wafer support parts 3A constituted so that they can stop at each position of an upper-stage, a middle-stage and a lower-stage and support marginal parts of the wafers W1, W2. The upper-stage finger 2A faces a height position between an upper-stage position and a middle- stage position of the wafer support part 3A, and the lower-stage finger 2B faces a height position between a middle-stage position and a lower-stage position of the wafer support part 3A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer transfer apparatus and a wafer transfer method, and more particularly, to a transfer step of supplying an unprocessed wafer to a wafer processing apparatus, and a transfer step of collecting a processed wafer from the wafer processing apparatus. The present invention relates to an improved wafer transfer apparatus and a method of transferring a wafer, which can improve the transfer efficiency of a wafer by integrating the steps and thereby improve the processing efficiency of a wafer processing apparatus.

[0002]

2. Description of the Related Art A wafer processing apparatus is an apparatus for performing various dry processes such as dry etching, ion etching, ashing, and plasma deposition on a wafer used for a semiconductor substrate or the like. A robot arm is usually used for a wafer transfer operation for supplying an unprocessed wafer to such a wafer processing apparatus and collecting a processed wafer from the wafer processing apparatus.

The robot arm has a tongue-shaped finger capable of horizontally supporting and transporting a wafer at a tip end of the arm which can rotate and bend and extend in a horizontal plane (see Japanese Patent Application Laid-Open No. 7-228306). ). Such a robot arm takes out one wafer from a carrier in which a plurality of unprocessed wafers are accommodated on a finger, transports it to a wafer processing apparatus, and supplies it to a susceptor for holding a wafer. Further, the processed wafer is taken out from the susceptor onto the finger, and is transported to a buffer device for cooling or the like to be collected. That is, the robot arm alternately repeats the operation of supplying an unprocessed wafer to the susceptor and collecting the processed wafer from the susceptor.

[0004]

By the way, the robot arm as the above-described wafer transfer device takes out a processed wafer from the susceptor onto a finger, transfers it to a cooling buffer device or the like, and collects the wafer. Otherwise, unprocessed wafers cannot be supplied on the susceptor. In other words, there is a problem that the transporting step of collecting processed wafers and the transporting step of supplying unprocessed wafers are required independently, resulting in poor transport efficiency.
As a result, there is a problem that a large process dead time occurs in the wafer processing apparatus, which hinders an improvement in wafer processing efficiency.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object a transport step of supplying an unprocessed wafer to a wafer processing apparatus and a transport step of collecting a processed wafer from the wafer processing apparatus. An object of the present invention is to provide a wafer transfer apparatus and a wafer transfer method that can improve the transfer efficiency of a wafer by integrating the steps and thereby improve the processing efficiency of a wafer processing apparatus.

[0006]

In order to achieve the above object, a wafer transfer apparatus according to the present invention supplies an unprocessed wafer to a susceptor for holding a wafer of a wafer processing apparatus and processes the unprocessed wafer from the susceptor. A robot arm for horizontally supporting and transporting a wafer, and a wafer elevating mechanism attached to the susceptor, wherein the robot arm comprises upper and lower two-stage fingers for supporting the wafer. The wafer elevating mechanism has a plurality of wafer supporting portions configured to be able to stop at an upper position, a middle position and a lower position and to be able to support a peripheral portion of the wafer, and the upper and lower two-stage fingers are The upper finger faces the height position between the upper position and the middle position of the wafer support portion, and is located at the height position between the middle position and the lower position. Characterized in that provided as to face stage of fingers.

Further, the wafer transfer method according to the present invention comprises:
In the wafer transfer method using the wafer transfer device, each wafer supporting portion supporting a processed wafer on a susceptor is raised to an upper position, and then, an unprocessed wafer is supported on a lower finger. After the upper and lower fingers enter below the processed wafer, each wafer support is lowered to the middle position, and the processed wafer is placed on the upper finger. After leaving the elevating area, each wafer support is lowered to the lower position, and then the upper and lower fingers are moved into the elevating area of the wafer, and then each wafer support is raised to the middle position, thereby lowering the upper fingers. The unprocessed wafer is supported on each wafer support, and then the upper and lower fingers are moved out of the elevating area of the wafer. The unprocessed wafer and supplying on a susceptor by lowering the Eha support portion to the lower position.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a wafer transfer apparatus and a wafer transfer method according to the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a robot arm and a wafer elevating mechanism of a wafer transfer apparatus, FIG. 2 is a vertical cross-sectional view of a wafer processing apparatus using the wafer transfer apparatus, FIG. 3 is a vertical cross-sectional view of a wafer lift mechanism, and FIG. It is an explanatory view of a transportation method.

As shown in FIG. 1, the wafer transfer apparatus of the present invention supplies an unprocessed wafer (W1) to a wafer holding susceptor (1) of a wafer processing apparatus and processes the unprocessed wafer (W1) from above the susceptor (1). This is an apparatus for collecting used wafers (W2). Such a wafer transfer device includes a wafer (W
1) includes a robot arm (2) for horizontally supporting and transporting (W2) and a wafer elevating mechanism (3) attached to the susceptor (1).

In the present invention, the robot arm (2) has upper and lower two-stage fingers (2A) and (2B) for supporting the wafers (W1) and (W2). Further, the wafer elevating mechanism (3) includes a plurality of wafer supporting portions (3A) configured to be able to stop at the upper position, the middle position, and the lower position and to be able to support the peripheral portions of the wafers (W1) and (W2). Have. Then, the upper and lower two-stage fingers (2
A) and (2B) are upper fingers (2A) at a height position between the upper position and the middle position of the wafer support (3A).
And the lower finger (2B) faces the height position between the middle position and the lower position. The fingers (2A) and (2B) include a wafer (W
In order to reduce the adhesion of particles to the back surfaces of 1) and (W2), fingers having a shape capable of supporting the peripheral portions of the wafers (W1) and (W2) are more preferable.

The wafer processing apparatus is an apparatus capable of performing various dry processes such as dry etching, ion etching, ashing, and plasma deposition on an unprocessed wafer (W1). For example, the wafer processing apparatus is configured as shown in FIG. ing. That is, the wafer processing apparatus (4) includes a resonator (6) disposed on a horizontal base (5) of a gantry, a processing chamber (7) disposed below the base (5), and a resonator ( 6) and a high frequency power supply (not shown) for supplying high frequency power of a predetermined frequency.

[0012] The resonator (6) is configured to be capable of reducing pressure, and a reaction vessel (6A) to which a plasma gas is supplied;
The resonance coil (6) wound around the outer periphery of the reaction vessel (6A)
B) and an outer shield (6C) made of aluminum or the like arranged on the outer periphery of the resonance coil (6B).

The reaction vessel (6A) is a cylindrical vessel made of quartz glass having an open bottom surface and a dome-shaped upper surface, and a slightly enlarged lower end edge is formed on the upper surface of the base (5). It is airtightly locked via a ring-shaped flange (6D). At the top of the reaction vessel (6A), a thin tube (6E) for introducing a plasma gas is integrally provided. A gas supply pipe (6F) extending from a gas supply device including various gas containers and capable of supplying a plasma gas at an appropriate flow rate is connected to the thin tube (6E).

The resonance coil (6B) is formed by a plurality of supports (6G) which are formed of an insulating material into a flat plate shape and are vertically provided on the upper end surface of the flange (6D). Both ends of the resonance coil (6B) are connected to an outer shield (6C) that is electrically grounded, and an appropriate portion between both ground points of the resonance coil (6B) whose both ends are grounded is connected via a movable tap. To a high frequency power supply (not shown).
The electrical length of the resonance coil (6B) is adjusted to, for example, one wavelength of the power supply frequency.

The outer shield (6C) is connected to the reaction vessel (6C).
A) and the bottom surface covering the resonance coil (6B) are formed in an open cap shape. The lower edge of the outer shield (6C) is supported on the flange (6D).

The processing chamber (7) is continuous with the inside of the reaction vessel (6A) through an opening formed on the upper surface thereof and an opening provided in the base (5). An exhaust pipe (8) leading to a vacuum pump is attached to a bottom plate (7A) constituting the bottom of the processing chamber (7), and the exhaust pipe (8) is provided inside the processing chamber (7) and the reaction vessel (6A). The pressure can be reduced to a predetermined degree through 8). And processing room (7)
A baffle plate (9) having a communication hole is horizontally suspended inside the susceptor (1).
The wafer elevating mechanism (3) is arranged below the baffle plate (9). Also,
The upper portion of the processing chamber (7) is continuous with the gate valve (10) through an opening formed in the side wall, and the gate valve (10) can be maintained at the same degree of vacuum as the processing chamber (7). A load lock container (not shown) is connected. The supply operation of the unprocessed wafer (W1) and the collection operation of the processed wafer (W2) are performed by the gate valve (1).
0).

In the wafer processing apparatus (4) having such a configuration, the inside of the processing chamber (7) and the reaction vessel (6A) is, for example, 1 through an exhaust pipe (8) by driving a vacuum pump.
The pressure is reduced from 0 mTorr to 20 Torr. Then, while maintaining the degree of vacuum in the reaction vessel (6A), a plasma gas is supplied through the gas supply pipe (6F), and a high frequency power of, for example, 27.12 MHz is supplied from a high frequency power supply (not shown). As a result, an induced electric field is generated around the resonance coil (6B), and a donut-shaped induction plasma is excited at, for example, an intermediate height position of the reaction vessel (6A) corresponding to an electric midpoint of the resonance coil (6B). You. Then, the unprocessed wafer (W1) is appropriately processed by the induction plasma.

As shown in FIG. 1, the robot arm (2) is capable of turning and bending and extending in a horizontal plane.
C) has the fingers (2A) and (2B) at the tip of
Each of the fingers (2A) and (2B) has a wafer support (3
A) Projections are provided in parallel at predetermined intervals so that they can enter between the upper position and the middle position and between the middle position and the lower position. The robot arm (2) is configured to be able to transport the wafers (W1) and (W2) on the upper and lower fingers (2A) and (2B) while horizontally supporting the central portion thereof.

On the other hand, as shown in FIG. 3, the wafer elevating mechanism (3) has a plurality of wafers (for example, 3) which can vertically move up and down through the baffle plate (9) and the susceptor (1).
) Of the lifting rods (3B).
Each of the wafer supporting portions (3A) is provided at the upper end of B). Each lifting rod (3B) is, as shown in FIG.
The susceptors (1) are arranged at substantially equal intervals on the periphery of the susceptor (1) so as to form a concentric circle. Then, each wafer support part (3
A) is protruded substantially horizontally toward the center of the susceptor (1), and the wafers (W1), (W2)
Are formed to fit the outer peripheral portion of. Further, a concave portion in which each wafer support portion (3A) can be depressed is formed on the upper surface of the susceptor (1).

As shown in FIG. 3, the lifting rod (3B)
Is erected on a movable plate (3C) arranged in parallel below the bottom plate (7A). A bellows (3D) is provided between the movable plate (3C) and the bottom plate (7A) to hermetically cover the periphery of each lifting rod (3B). In addition, the movable plate (3C)
The linear bearing (3) to which the guide bar (3E) fits
F) and a ball nut (3H) into which the ball screw (3G) is screwed are fixed respectively.

Below the movable plate (3C), a fixed plate (3I) supported by a bottom plate (7A) is disposed, and below the fixed plate (3I), a motor housing case (3I) is provided.
J) are connected in series. Then, the guide bar (3
E) penetrates the movable plate (3C), is fitted to the linear bearing (3F), and is vertically installed between the fixed plate (3I) and the bottom plate (7A). The ball screw (3G) penetrates through the fixed plate (3I) and the movable plate (3C) and is screwed to the ball nut (3H). The outer periphery of the lower end is fixed via the bearing (3K). ) Is rotatably supported. And ball screw (3G)
Is connected via a coupling (3M) to a rotation shaft of a servomotor (3L) fixed in the motor housing case (3J).

In the wafer elevating mechanism (3) having such a configuration, the ball screw (3) is driven by the servomotor (3L).
By driving G) to rotate forward or reverse, each lifting rod (3B) moves up and down together with the movable plate (3C). Then, by the rotation control of the servo motor (3L), the wafer support portion (3A) at the upper end of each lifting rod (3B) moves the wafers (W1) and (W2) to the upper surface of the susceptor (1) as shown in FIG. From the lower position to be placed on the upper position to the middle position and the upper position.

Next, a description will be given of a wafer transfer method according to the present invention using the wafer transfer apparatus configured as described above.
In the wafer transfer method of the present invention, first, as shown in FIG. 4A, the central portion of the unprocessed wafer (W1) is supported on the lower finger (2B) of the robot arm (2). The upper and lower fingers (2A) and (2B) face the susceptor (1) of the wafer processing apparatus (4). On the other hand, in the wafer elevating mechanism (3), each elevating rod (3B) is raised by rotation control of the servo motor (3L) to support the peripheral portion of the processed wafer (W2) on the susceptor (1). The wafer support (3A) is raised to the upper position.

Next, as shown in FIG. 4B, the upper and lower fingers (2A) and (2B) are treated with the processed wafer (W).
Enter below 2). Thereafter, as shown in FIG. 4C, each wafer supporting portion (3A) is lowered to the middle position, and the central portion of the processed wafer (W2) is placed on the upper finger (2A).

Subsequently, as shown in FIG. 4D, the upper and lower fingers (2A) and (2B) are moved out of the elevating area of the wafer, and then each wafer support (3A) is lowered to the lower position. . After that, as shown in FIG. 4E, the upper and lower fingers (2A) and (2B) enter the elevating area of the wafer. Next, the lower fingers (2) are raised by raising each wafer support (3A) to the middle position.
B) The peripheral edge of the unprocessed wafer (W1) is supported on each wafer support (3A).

Next, as shown in FIG. 4 (f), the upper and lower fingers (2A) and (2B) are withdrawn from the elevating area of the wafer, and the processed fingers placed on the upper finger (2A). Collect the wafer (W2). After that, each wafer supporting portion (3A) is lowered to the lower position to supply the unprocessed wafer (W1) onto the susceptor (1).

That is, according to the wafer transfer method of the present invention, each wafer supporting portion (3A) supporting the processed wafer (W2) on the susceptor (1) is moved from the lower position to the upper position, the middle position, and the lower position. The upper and lower fingers (2A), (2A), which move up and down to the middle position and the lower position, and support the unprocessed wafer (W1) on the lower finger (2B).
B) makes two reciprocations of the movement of the wafer to and from the elevating area in synchronization with the elevating operation of each wafer supporting part (3A), thereby collecting the processed wafer (W2) from the susceptor (1), The wafer (W1) can be supplied on the susceptor (1). Therefore, the transporting step of supplying the unprocessed wafer (W1) to the wafer processing apparatus (4), and the processing of the processed wafer (W1) from the wafer processing apparatus (4).
The transfer process for collecting 2) and the transfer process for one round trip of the robot arm can be integrated to improve the transfer efficiency of the wafers (W1) and (W2), and the process dead time in the wafer processing apparatus (4) can be reduced. The processing efficiency can be improved due to the reduction.

[0028]

As described above, according to the wafer transfer device and the wafer transfer method according to the present invention, each wafer supporting portion supporting the processed wafer on the susceptor is moved from the lower position to the upper position, the middle position, Lower position, middle position,
The upper and lower fingers supporting the unprocessed wafer on the lower finger move up and down to the lower position, and reciprocate back and forth two times with respect to the lifting area of the wafer in synchronization with the lifting operation of each wafer supporting portion. The processed wafer can be recovered from the susceptor, and the unprocessed wafer can be supplied to the susceptor. In other words, the transfer process of supplying unprocessed wafers to the wafer processing device and the transfer process of collecting processed wafers from the wafer processing device are integrated into a single reciprocating transfer process of the robot arm to improve wafer transfer efficiency. As a result, the processing dead time in the wafer processing apparatus can be reduced, and the processing efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a robot arm and a wafer elevating mechanism of a wafer transfer device according to the present invention.

FIG. 2 is a vertical sectional view of a wafer processing apparatus in which a wafer transfer device is used.

FIG. 3 is a vertical sectional view of a wafer elevating mechanism.

FIG. 4 is an explanatory diagram of a wafer transfer method.

[Explanation of symbols]

 1: Susceptor 2: Robot arm 2A: Upper finger 2B: Lower finger 2C: Arm 3: Wafer elevating mechanism 3A: Wafer support 3B: Elevating rod 3C: Movable plate 3D: Bellows 3E: Guide bar 3F: Linear bearing 3G : Ball screw 3H: Ball nut 3I: Fixed plate 3J: Motor storage case 3K: Bearing 3L: Servo motor 3M: Coupling 4: Wafer processing unit 5: Base 6: Resonator 6A: Reaction vessel 6B: Resonant coil 6C: Outer shield 6D: Flange 6E: Narrow tube 6F: Gas supply tube 6G: Support 7: Processing chamber 7A: Bottom plate 8: Exhaust tube 9: Baffle plate 10: Gate valve W1: Unprocessed wafer W2: Processed wafer

Claims (2)

[Claims] 1. A wafer transfer apparatus for supplying an unprocessed wafer onto a susceptor for holding a wafer of a wafer processing apparatus and collecting a processed wafer from the susceptor, wherein the wafer transfer apparatus horizontally moves the wafer. A robot arm supporting and transporting the wafer and a wafer elevating mechanism attached to the susceptor, wherein the robot arm has upper and lower two-stage fingers for supporting a wafer, and the wafer elevating mechanism includes an upper position and a middle position. And a plurality of wafer supports configured to be able to stop at the lower position and to support the peripheral edge of the wafer, wherein the upper and lower two-stage fingers are located between the upper position and the middle position of the wafer support. The upper finger faces the height position, and the lower finger faces the height position between the middle position and the lower position. Wafer transfer equipment. 2. A wafer transfer method using the wafer transfer device according to claim 1, wherein each wafer supporting portion supporting the processed wafer on the susceptor is raised to an upper position, and then the unprocessed wafer is supported. After the upper and lower fingers where the wafer is supported on the lower finger enter below the processed wafer, each wafer support is lowered to the middle position, and the processed wafer is placed on the upper finger. Subsequently, after the upper and lower fingers are withdrawn from the elevating area of the wafer, each wafer support is lowered to the lower position, and then the upper and lower fingers enter the elevating area of the wafer, and then each wafer support is moved to the middle position. Support the unprocessed wafer on the lower finger on each wafer support by raising it to a position, then raise and lower the upper and lower fingers A wafer transfer method comprising supplying an unprocessed wafer to a susceptor by lowering each wafer support unit to a lower position after leaving the area.