JP2009170740A - Transfer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem, wherein wafer surface is exposed to the atmosphere, resulting in oxidization, when a heat treated wafer is carried and consequently the quality of a wafer deteriorates. <P>SOLUTION: The whole transportation system of wafer is not filled with an inert gas, but a local inert gas atmosphere is provided to a wafer mounted above end effectors 12a and 12b. Consequently, deterioration of a wafer can be prevented with a small quantity of inert gas. A wafer carrying device in the transfer system is equipped with fans 20a and 20b for supplying inert gas to the wafer surface, in order to prevent oxidation of a wafer by forming a gas phase of inert gas in a gap between the wafer and the fan. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a transfer apparatus and a transfer system including a blowing unit that blows an inert gas or the like onto a wafer placed on an end effector.

The transfer system includes a transfer device such as a SCARA robot to transfer a semiconductor wafer (hereinafter referred to as a wafer) between a cassette (FOUP cassette) for transfer in a clean room and various processing apparatuses. Prepare.

When a wafer is transferred from various processing apparatuses to a cassette for storing a heat-treated wafer by a conventional transfer system, the surface of the wafer may be oxidized by being exposed to the atmosphere, and the quality of the wafer may be deteriorated. In such a case, the oxidation of the wafer is prevented by replacing the internal atmosphere of the transfer system with an inert gas such as nitrogen from the atmosphere. As an example, a conventional transport system 60 of Patent Document 1 will be described below with reference to FIG. In this conventional transfer system 60 (semiconductor manufacturing apparatus), a fan filter unit 62 is provided above the first housing 61 for keeping the inside clean, and clean air is blown into the apparatus. A conventional transfer device 65 for transferring the wafer 5 from the FOUP cassette 63 to the processing device 64 is provided on the inner floor surface. In the conventional conveyance system 60 of this patent document 1, the clean gas which blows with a fan filter unit supplies clean inert gas (nitrogen) instead of air conventionally. The inside of the conventional transfer system 60 and the second casing 68 having a lid 67 capable of opening the entire stage 66 on which the FOUP cassette 63 is placed are filled with an inert gas. A large amount of inert gas is required. Then, if a large amount is sucked, the human body is in danger and handling is difficult. In addition, running costs are required.
JP 2002-43391 A

An object of the present invention is to provide a transfer apparatus and a transfer system that prevent deterioration of a wafer or the like with a small amount of inert gas.

The transfer apparatus of the present invention transfers a wafer in a clean environment. This transfer device includes an end effector for placing a wafer, an arm body that moves the end effector in a horizontal direction, a base that cantilever-supports the arm body, and a blower that blows inert gas. It is. In addition, the air blowing surface of the air blower is provided so as to be parallel to the wafer placed on the end effector, and an inert gas gas phase is formed in the gap between the air blowing surface and the wafer.

In addition, the transfer device of the present invention may have a configuration in which the side wall is an edge of the air blowing surface and is provided around the edge of the wafer. The gap between the wafer and the blower is smaller than when no side wall is provided. That is, the area of the discharge port (gap) for discharging the inert gas into the atmosphere can be further reduced. As a result, the pressure in the gap becomes higher than the outside of the gap, and a stable gas phase can be formed.

Moreover, the conveying apparatus of this invention is good also as a structure provided with the side wall of a ventilation means inclining with respect to a perpendicular direction. As a result, it is possible to prevent the inert gas entraining the atmosphere from being blown onto the wafer surface.

The arm body of the transfer device of the present invention may be a well-known one. In addition to the transport apparatus as shown in FIG. 1, a transport apparatus having a configuration in which an end effector is attached to a movable part of a linear motion mechanism by a ball screw shaft that is operated by driving of a motor so as to be movable in the horizontal direction. Moreover, it may have a linear motion mechanism that is driven by a magnet and a coil arranged in series instead of the ball screw shaft.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.

1 includes an inert gas cylinder 21, a valve 22, a pipe 23, a pressure chamber (not shown), and a blower port member (not shown). When the desired internal pressure of the cylinder is low, a configuration in which a blower pump 24 is separately provided in addition to (or instead of) the cylinder 21 may be adopted. In addition, a heater or a gas cooling mechanism, a temperature measuring device, a humidity adjusting device and a humidity measuring device for adjusting the blowing humidity, and an ionizer (static eliminating device) for removing static electricity, which are not shown, are separately adjusted. There is a case to prepare. In order to control these operations and the state of the gas to be blown, it is performed by an electronic circuit on the control board of the control device 30 and program software.

This transport device 1 includes a base 2, a body portion 3, an arm body including first arms 10a and 10b, and second arms 11a and 11b, end effectors 12a and b, and blowers 20a and b. Consists of.

The arms 10a and 10b are provided on the upper part of the body part 3 so as to be rotatable in a horizontal plane. The arms 11a and 11b are provided at the upper ends of the respective arms 10a and 10b so as to be rotatable in a horizontal plane. Further, the end effectors 12a and 12b are respectively provided at the upper ends of the arms 11a and 11b so as to be rotatable in a horizontal plane. Drive units (not shown) that drive the arms 10a, 10b, 11a, and 11b and the end effectors 12a and 12b are provided inside the casing of the body 3. In the first arm 10a, 10b and the second arm 11a, 11b, a belt and a pulley or a plurality of gears for transmitting the power of the driving source to the arm 11a, b or the end effector 12a, b or a plurality of gears are arranged in parallel. Prepare. Since the belt / pulley mechanism and the like are well known, description thereof will be omitted. As a result, the first arm 10a, b rotates, and the second arm 11a, b rotates in the opposite direction to the first arm 10a, b, and rotates by a double angle, thereby the end effector 12a. , B can be moved back and forth.

The transfer apparatus 1 is provided in the transfer system for transferring a wafer from a processing apparatus that performs adjacent heat treatment so as to be communicable with the inside of the transfer system onto a temporary shelf for temporary cooling. In such a case, the inside of the processing apparatus and the inside of the temporary storage shelf may be filled with an inert gas. In such a case, when there is a distance between the processing apparatus and the temporary storage shelf and the space between the processing apparatus and the temporary shelf is an air atmosphere, the wafer surface touches the air during the transfer and the surface is oxidized. Therefore, the transport device 1 of the present invention is used in such a situation.

Inside the casing of the body portion 3 of the transport apparatus 1 is provided with a lifting drive mechanism (not shown) that moves the arm 10 and the like up and down, for example, a ball screw shaft and a motor. As a result, the end effector 12 can also deliver wafers that have different heights and are placed in the processing apparatus or the like.

Inside the body part 3 of the transport apparatus 1 is provided with a turning drive mechanism for turning the arm 10 or the like, for example, a structure composed of a motor, a pulley and a belt, or a structure composed of a motor and a planetary gear. Thereby, the advance / retreat direction of the end effector 12 can be directed to the access direction of a predetermined processing apparatus.

In order to take out (carry) the wafer placed on the processing apparatus or the like by the transfer device 1, the end effectors 12a and 12b are moved forward and backward by the operation of the first arms 10a and 10b and the second arms 11a and 11b. The end effectors 12a and 12b are inserted below the wafer to be transported, and the blowers 20a and 20b are inserted above the wafer, and then the wafer is placed on the end effectors 12a and 12b by the operation of the lifting drive mechanism. And can be transported. The control of the blower, for example, the blower start command, the blower stop command and the management of the blown amount, temperature, humidity, etc. is performed by the control device 30 or the like.

In addition, the rotation control of each motor provided in the transport device 1 is performed collectively by electronic circuit and program software on the control board of the control device 30 or by being distributed with a separate control device (not shown).

In the present embodiment, the air blower 20 excluding the inert gas cylinder 21 is located at a position spaced upward from the wafer placed on the upper portions of the end effectors 12a and 12b, on the end effectors 12a and b. The end effectors 12a, b are provided in a cantilevered manner so as to be rotatable at the upper ends of the arms 10a, 10b. The root side is the side that is cantilevered. .) An inert gas cylinder 21 is provided at a place other than the top of the end effector 12. In this embodiment, the cylinder 21 is removed from the blower device 20 when the cylinder 21 is mounted on the end effectors 12a, b and the like. This is because of the above-mentioned problem. About providing the cylinder 21 in the inside of the conveying apparatus 1, or in the conveying apparatus 1 that can solve the above-mentioned problems such as sufficient rigidity, the cylinder 21 may be provided in the conveying apparatus 1.

In the air blower 20 shown in FIG. 2, the air blowing surface 32 is installed so as to be parallel to the wafer 5 placed on the end effector 12. The distance L between the upper surface of the wafer 5 and the blower surface 32 of the blower 20 is about 5 mm to 15 mm. However, the distance L is optimal in relation to the wind speed blown from the blower 20 and the area of the blower surface 32. A numerical value is to be determined. Here, “optimal” means a state in which the air is blown from the blower 20 to the wafer 5 and the surface of the wafer 5 is sufficiently wrapped with an inert gas atmosphere and does not come into contact with the atmosphere. Furthermore, in the simulation to be described later, even if there is a cross wind of 1 m / s generated by moving the blower 20 fixed to the top of the end effector 12 together with the end effector 12 in the horizontal direction, it is optimal if the air is not caught in the gap. (It is judged whether or not there is a gas flow from the outside of the air blowing surface by a flow diagram or the like). The streamline diagram will be described later with reference to FIGS.

In the embodiment of the present invention, the inert gas inside the cylinder 21 is placed in the pressurizing chamber 31 with the flow rate adjusted by passing through the valve 22 through the pipe 23. Thereby, the quantity of the gas ejected from the ventilation surface 32 is adjusted. The valve 22 receives an electric signal from the control device 30 and is electrically operated or manually operated to adjust the air blowing amount and blow the air into the pressurizing chamber 31.

In this embodiment, a filter 25 that removes particles and the like is provided in the middle of the pipe 23. Thereby, a clean inert gas from which particles have been removed in advance can be blown onto the surface of the wafer 5.

A member of the air blowing port 34 is provided on the inner bottom surface 33 of the pressurizing chamber 31. The member of the air blowing port 34 is provided with a punch hole in the plate material, and is used for ejecting the inert gas compressed in the pressurizing chamber 31 from the air blowing port 34 at a desired flow rate. Moreover, the other Example of the ventilation port 34 is mentioned later.

In FIG. 2, the flow of the inert gas blown to the wafer 5 is indicated by arrows. In the blower 20 of FIG. 2, the inert gas blown from the upper center of the wafer 5 flows toward the periphery of the wafer. As a result, a gas phase of an inert gas is formed on the air blowing surface 32 and the surface of the wafer 5, and a gas (for example, air) other than the inert gas is prevented from touching the surface of the wafer 5 (the surface in contact with the air blown by the air blower 20). be able to. The distance L from the air blowing surface 32 to the surface of the wafer 5 is a distance that can form a gas phase at this time.

In the present embodiment, a specific example of the blower 20 for the 300 mm wafer 5 is shown, but the shape and size of the wafer are not limited. The distance from the surface of the wafer 5 to the blower surface is about 5 mm to 15 mm. If the distance is smaller than 5 mm, an accident occurs in which the blower 20 and peripheral devices come into contact when the end effector 12 moves back and forth due to the operation of the transfer device 1. Sometimes it is for safety. When the distance is 15 mm or more, the atmosphere outside the gas phase is entrained at the peripheral edge of the wafer, and as a result, the surface of the wafer 5 and the atmosphere come into contact with each other and oxidize.

In the first embodiment, in the transfer apparatus 1 of FIG. 1, the transfer apparatus 1 moves (relatively) in the horizontal direction at 1 m / s (the upper surface of the wafer 5 placed on the end effector 12, the blower 20, and the like). The simulation was performed under the following conditions when a cross wind of 1 m / s was blown into the gap.

The simulation was performed for the cases in which the amount of air blown by the blower 20 was 0.03 m / s, 0.05 m / s, 0.10 m / s, 0.15 m / s, and 0.20 m / s.

A simulation was performed when the gap from the upper surface of the wafer 5 to the blower 20 was 5 mm, 10 mm, and 15 mm.

When the diameter of the air blowing surface 32 of the air blowing device 20 (the air blowing surface means the surface of the air blowing member facing the wafer. The shape in this embodiment is a circle) is 300 mm, 310 mm, and 320 mm. A simulation was performed.

3 and 4 show simulation results (results within the range indicated by the rectangular parallelepiped 24) regarding the flow of the inert gas blown from the blower 20. FIG. 3 shows a case where the diameter of the blower surface 32 is 300 mm, the wind speed is 0.03 m / s, and the gap L is 5 mm. FIG. 4 shows a case where the diameter of the air blowing surface 32 is 300 mm, the wind speed is 0.05 m / s, and the gap L is 5 mm. 3 and 4 show streamlines (perspective views) when the wafer 5 placed on the end effector 12 is viewed through the blower 20.

Moreover, in Table 1 above, there is a description as to whether or not it is optimal (indicated by “◯” in Table 1). The determination is made based on whether or not there is a gas flow from the wafer toward the center of the wafer. That is, as shown in FIG. 3, the gas flow from the atmosphere side toward the center of the wafer 5 (○ is not optimal when there is a circle surrounded by A, and is indicated by ×. As shown in FIG. It is optimal when it is a gas flow to the side, and is marked with a circle.

In FIG. 5a, the top view of the ventilation surface 32 (what provided the punch hole in the board | plate material) shown in FIG. 1 is shown. 5b and 5c show different ones from the air blowing surface 32a shown in FIG.

The air blowing surface 32b of FIG. 5b has shown the air blowing surface 32b which increased / decreased the number of the holes of the location which ventilates with respect to the wafer 5 with respect to the air blowing surface 32a of FIG. 5a. In the air blowing surface 32 b, air blowing ports 34 are provided at locations on the air blowing surface 32 b corresponding to the center of the wafer 5 and the edge of the wafer 5.
The same effect can be obtained even if the number of holes per area of the blower surface 32 is increased or decreased.

The blower surface 32c in FIG. 5c shows a hole whose size is increased or decreased. The blower surface 32 c includes a blower port 34 c larger than the blower port 34 at a location of the blower surface 32 c corresponding to the center of the wafer 5, and a blower surface 32 a and a blower surface 32 c corresponding to the edge of the wafer 5. The same air outlet 34 is provided. As a result, the air flow rate and the wind speed are adjusted according to the position on the wafer to be blown by blowing a predetermined amount of air on the surface of the wafer on average, or by blowing a large amount toward the center of the wafer toward the edge of the wafer. It is possible to adjust the air blowing state.
Moreover, about the ventilation port 34b, it is good also as an exhaust hole instead of a ventilation port.

In the air blower 20a of FIG. 6a, the direction of the air is inclined from the vertical with respect to the peripheral edge of the wafer 5 while the hole of the air blowing port 32 of the air blower 20 of FIG. , As indicated by arrows A and A ′). Specifically, it is possible to provide the blower opening 34 that is normally opened in the vertical direction so as to be inclined in the peripheral direction from the center side of the wafer 5 in the member of the blower 34. Thereby, it is possible to prevent the inert gas entrained in the atmosphere from being blown to the surface of the wafer 5.

The air blower 20b of FIG. 6b shows what is equipped with the piping 23 directly attached to the porous member 35 which is a member of the air blowing port 34, without providing the pressurizing chamber 31, like the air blower 20 of FIG. Yes. Even if the pressurizing chamber 31 is not provided, the inert gas supplied from one place through the holes of the continuous porous member 35 is not discharged to the outside at a time. That is, the inert gas travels on average and in a wide range through the continuous pores in the porous body. For this reason, the whole height (M2) of the air blower 20b can be made smaller than the height (M1 in FIG. 6) of the conventional air blower 20a.

The air blower 20 c in FIG. 6 c includes the pressurizing chamber 31 as in the air blower 20 in FIG. 2, but the member of the air blowing port 34 provided in the inner bottom surface 33 is a porous member 35. Thereby, even when the continuous holes of the porous member 35 are uniform as a whole, it is possible to blow the air uniformly over the entire surface of the air blowing surface 32.

The air blower 20d of FIG. 6d is the same as the air blower 20 of FIG. 2, but includes a side wall 36 at the location of the air blowing surface 32 corresponding to the upper part of the wafer edge. Thereby, the width (L1) by which the inert gas blown toward the wafer 5 from the sending device 20d is exhausted to the outside through the gap between the blower surface and the wafer surface is larger than the conventional width (L in FIG. 2). Since it becomes narrow, the pressure of the inert gas in a clearance becomes higher than the outside, and the entrance of outside air from the outside can be prevented. That is, it is possible to further prevent oxidation due to the outside air touching the surface of the wafer 5.

FIG. 7 shows an embodiment of a transport device 50 different from that in FIG. In the transport device 1 in FIG. 1, the blowers 20 a and b are provided in the end effectors 12 a and b, whereas in the transport device 50 in FIG. 6, the blowers 20 c and d are connected to the body portion 3 via the four columns 51. Is provided. Further, the height of the blower 20c, d is set so as to be a position determined to be optimal from the wafers 5a, b placed on the end effectors 12a, b by the above simulation or the like. Further, as shown in FIG. 6, the shape of the air outlet 34 is such that the arm body (the arm body is composed of the first arm 10 and the second arm 11) of the transfer device 50 is in the standby position (the arm body is retracted). In this state, that is, as shown in the figure, the arm body is bent.) It is provided so as to be above the end effectors 12a and 12b.

FIG. 8 is a partially cutaway perspective view showing a state in which the transport device 50 of FIG. 7 is installed in the transport system 52. The transport device 50 transports the wafer 5 from the processing device 53 that performs processing such as heating to a temporary shelf 54 for cooling the heat generated by the heat processing. A state in which the arm body of the transfer device 50 is rotated and the upper end effector 12b is inserted below the wafer 5 placed inside the processing device 53 is shown. The processing device 53 is filled with an inert gas (nitrogen). In addition, the outer wall surface 54 of the processing device 53 includes a blower device 20e similar to the blower devices 20c and 20d of the transfer device 50. The blower device 20e and the blower device 20c or 20d of the transport device 50 are provided with the blower surfaces 34 having the same height and with a slight gap therebetween.

FIG. 9 shows a state in which the transfer device 50 in the state of FIG. 8 is swung so as to face the opening of the temporary shelf, and the upper arm body is operated to heat the wafer 5. The state which is transporting into the temporary shelf 54 is shown. Note that the wafer 5 inside the temporary storage shelf 54 and the end effector 12a inserted below the wafer 5 are indicated by dotted lines.

FIG. 1 is a perspective view showing an embodiment of a transport apparatus according to the present invention. FIG. 2 is a cross-sectional side view showing the blower of FIG. FIG. 3 shows the result of the simulation. FIG. 4 shows the result of simulation different from FIG. FIG. 5 is a plan view showing an embodiment different from the air blowing port of FIG. FIG. 6 is a cross-sectional side view showing an embodiment of a blower different from FIG. FIG. 7 shows an embodiment of a transport device different from FIG. FIG. 8 is a partially cutaway perspective view showing a state in which the transfer apparatus of FIG. 7 is installed in the transfer system. FIG. 9 is a partially cutaway perspective view showing a state in which the transfer apparatus of FIG. 7 is installed in the transfer system. FIG. 10 is a side sectional view showing a conventional transport system.

Explanation of symbols

1, 50 Conveyor
2 base
3 trunk
5 Wafer
10a, b 1st arm
11a, b Second arm
12, 12a, b End effector
20, 20a, b, c, d, e
21 cylinder
22 Valve
23 Piping
25 filters
30 Control device
31 Pressurizing chamber 32 Air blowing surface 33 Internal bottom surface of the pressurizing chamber
34 Air outlet 35 Porous member 36 Side wall 51 Support column 52 Transfer system 53, 64 Processing device 54 Temporary shelf 60 Conventional transfer system 61 First housing 62 Fan filter unit 63 FOUP cassette 65 Conventional transfer device 66 Stage 67 Lid 68 Second housing

Claims (3)

In a transfer apparatus for transferring a wafer in a clean environment, an end effector for placing the wafer, an arm body for moving the end effector back and forth horizontally,
A base that cantilever-supports the arm body, and a blower that blows an inert gas, and a blower surface of the blower is provided to be parallel to the wafer placed on the end effector, A transfer apparatus, wherein a gas phase of an inert gas is formed in a gap between a blower surface and a wafer. The transfer apparatus according to claim 1, wherein the side wall is an edge of the air blowing surface and is provided around the edge of the wafer. The conveying device according to claim 2, wherein the side wall of the blowing unit is provided to be inclined with respect to the vertical direction.