JPH09320973A - Wafer transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer transfer device for a heat processing furnace which prevents occurrence of particles and performs loading without degrading temperature recovery performance of the furnace. SOLUTION: The device comprises a rail 5, having a smooth surface and a round-expanded cross section, as a boat transfer mechanism for loading and discharging a boat 1, a wheel 2 running on the rail 5, and legs 3. The total weight of a wafer 18 and the boat 1 is supported by the wheel 2 at the front end of the boat 1 and the tow legs 3 at the rear end of the boat 1, which reduces the thermal capacity of an arm 4 which moves in and out of a furnace tube 10, and further transfers the boat 1 in a state close to soft-landing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer loading / unloading device for loading / unloading a plurality of wafers into / from a heat treatment furnace for performing a process such as diffusion or oxidation of a wafer which is a semiconductor substrate.

[0002]

2. Description of the Related Art FIGS. 6A and 6B are schematic sectional views for explaining a conventional wafer loading / unloading apparatus. As shown in FIG. 6, the wafer loading / unloading device is surrounded by a wafer loading boat 11 on which a plurality of wafers 18 are mounted side by side, wheels 13 rotatably attached to both ends of the boat 11, and a scavenger 12. The slide rod 14 for loading and unloading the boat 11 into and from the cylindrical furnace core tube 10 having the boat receiver 7 extending from the bottom of the opening at one end.
And a guide mechanism 15 for guiding the movement of the slide bar 14.
And

In this wafer loading / unloading apparatus, although the boat 11 is smoothly loaded / unloaded by the four wheels 13 attached to both ends of the boat 11, the inner wall surface of the quartz material, which has distortion or unevenness, remains as it is. Since the wheels 13 are in direct contact with each other, the protrusions on the inner wall surface are scraped off by the wheels 13. The shavings are used as particles in the wafer 18
However, there is a problem that the quality of the wafer 18 is seriously deteriorated by the adhesion to the surface.

FIG. 7 is a schematic sectional view for explaining a conventional wafer loading / unloading device. As a wafer loading / unloading device that solves such a problem of particle generation, for example, there is a device called a soft landing system shown in FIG. This apparatus is provided with a fork 17 having a guide mechanism 15a for moving the boat 11a up and down and moving it forward and backward in the longitudinal direction.
The foot 9a of a is floated and the boat 11a is carried in and out from the furnace core tube 10. That is, the boat 11a that causes generation of particles can be carried in and out without sliding on the inner wall of the furnace core tube 10.

[0005]

In the above-described wafer-loading / unloading apparatus of the soft landing type, although the problem of particle generation is solved, the fork of the fork is moved in order to support the total weight of the boat while supporting it in a cantilever manner with little bending. Higher rigidity is necessary. Even if the section modulus is increased in order to increase the rigidity, the volume of the fork itself increases, and as a result, the heat capacity of the fork increases, and the temperature inside the furnace core decreases significantly after the boat is lit. There is a problem that the temperature recovery of is reduced.

Further, since the weight of the fork itself becomes large, the mechanism for moving the fork becomes large, and further, it is necessary to make a long space in the longitudinal direction on the front surface of the heat treatment furnace, and the installation area of the apparatus becomes large. There is. Furthermore, the length of the fork that is cantilevered is long, for example, 2 to 3 m, and the deflection of the fork varies depending on the weight of the number of wafers loaded in the boat, and when a large number of wafers are loaded, the narrow furnace core tube It is difficult to adjust the vertical movement of the fork relative to the opening. This means that the number of loaded wafers is limited and complicated work such as adjusting the vertical movement range for each number of loaded wafers must be performed.

Therefore, it is an object of the present invention to minimize the generation of particles and to reduce the temperature recovery performance of the furnace, and without the need for complicated adjustments depending on the number of wafers loaded and the length of the apparatus. It is to provide a wafer loading / unloading device having a shorter directional length.

[0008]

A feature of the present invention is that it has a boat receiver that extends outward from the bottom of the opening at one end, and extends over the boat receiver in the lengthwise direction inside a horizontally arranged furnace core tube. A single rail that is laid down, a boat that mounts a plurality of wafers side by side in the longitudinal direction, one wheel that is on the tip side of the boat and travels on the rail with the boat, A loading / unloading device including an arm that moves a unicycle to move the boat into and out of the furnace core tube, and a moving mechanism that moves the arm.

Further, a connecting mechanism by which the arm can be attached to and detached from the rear end of the boat, and by the connecting mechanism, the arm is detached from the boat and placed on the bottom of the furnace core tube or the boat receiver. Is preferably provided with two foot members that support the wheel and the wheel at three points, or the arm mounts the boat and the wheel is mounted.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIGS. 1A and 1B are schematic sectional views for explaining a wafer loading / unloading device according to an embodiment of the present invention. As shown in FIG. 1, this wafer loading / unloading device has a boat receiver 7 extending outward from an opening 9 at one end and a boat receiver 7 extending in the longitudinal direction inside a horizontally arranged furnace core tube 10. One rail 5 laid across the rails, a holder for placing a plurality of wafers 18 side by side in the longitudinal direction, and one wheeled vehicle 2 rotatably mounted on one end and traveling on the rail 5, and this wheeled vehicle. 2 is a three-point support, and a boat 1 having a foot portion 3 attached to the other end, and a foot portion 3 for lifting a handle 8 of the boat 1 with a wheel 2 placed on a rail 5 are provided with a furnace core tube 10 An arm 4 that can be floated from the bottom and a boat moving mechanism 6 that moves the boat 1 in the furnace core tube with the legs 3 floating.

The rail 5 is removable and is fixedly held on the boat receiver 7. As shown in FIG. 1 (b), the wheels 2 of the boat 1 ride on the rails 5, and the contact sectional shape of the wheels 2 is a pair of guideable concavities and convexities. Basically, the cross section of the rail 5 is a convex arc or an inverted V shape in order to avoid accumulation of foreign matter.

FIG. 2 is a partial perspective view showing the furnace core tube of FIG. 1 in an extracted manner. As shown in FIG. 2, the rail 5 on which the boat 1 travels extends up to the boat receiver 7 of the furnace core tube 10, and a single quartz rod is polished to make the surface smooth and accurate. Has been done. Then, after leveling is performed on the bottom of the molded furnace core tube 10, the rail 5 which is precisely ground is welded to the bottom of the boat receiver 7. Also, FIG.
The quartz wheel 2 is rubbed with the rail 5 in advance so that the contact surfaces are even with each other. Moreover, the wheel 2
The rail 5 is in contact with only the upper guide portion of the rail 5 so that particles are not generated during traveling. Further, this rail 5 is a seamless rail so as not to give an impact.

On the other hand, the arm 4 for lifting the rear end of the boat 1 may have a length from the position of the handle 8 to the inlet of the scavenger 12 when the boat 1 is at the predetermined position of the furnace core tube 10. Further, the lifting height of the arm 4 may be such that the foot 3 is separated from the uneven surface of the furnace core tube 10 and the wall surface of the boat receiver 7, and the lifting force is slightly larger than half the weight of the boat 1. I'm done. The arm 4 does not need to have a particularly complicated beam structure in order to increase the rigidity, and the width of the arm 4 may be a uniform strength beam from a single plate material having a constant thickness. The boat 1 is the furnace core tube 1.
Since the wheel 2 and the two legs 3 are supported at three points in 0, even if the inner wall of the furnace core tube 10 has some irregularities, the boat 1 is always stable inside the furnace core tube 10. Placed on.

FIGS. 3A to 3C are schematic sectional views showing the operation sequence of the wafer loading / unloading apparatus of FIG. Next, the operation of the wafer loading / unloading device of FIG. 1 will be described with reference to FIG. First, as shown in FIG. 3 (a), when the boat 1 loaded with wafers 18 is started, the arm 4 is raised and the rear end of the boat 1 is lifted to lift the foot 8 from the wall surface of the boat receiver 7. Next, as shown in FIG. 3 (b), the boat 1 is pushed by the movement of the self-propelled movement mechanism 6 via the arm 4 and is moved by the rotation of the wheels 2 to reach a predetermined position in the furnace core tube 10. Boat 1 is sent. Then lower the arm 4 and the boat 1
Then, as shown in FIG. 3 (c), the arm 4 is retracted, and the boat 1 is completely charged. In addition, the operation of the boat 1 for unloading the furnace is the reverse of the above-described operation and is shown in FIG.
The order is from (c) to (b) and (a).

FIGS. 4A and 4B are schematic sectional views for explaining a wafer loading / unloading device according to another embodiment of the present invention. In this wafer loading / unloading apparatus, as shown in FIG. 4, an arm 4a carries the boat 1a and moves the arm 4a into and out of the boat 1a. Also,
The moving mechanism 6a includes only a mechanism for advancing and retracting the boat 1a, and does not have an arm up-and-down mechanism as in the above-described embodiment. Therefore, the arm 4a remains inserted in the furnace core tube 10 at the time of completion of the furnace entrance, and only moves forward at the time of furnace entrance and retreats at the time of furnace exit.

Since this arm 4a has a double-supported structure in which the other end is supported by the guide rail of the moving mechanism 6a with the wheel 2 as the fulcrum, the rigidity of the guide rail needs to be increased to some extent, but the arm 4a itself does not. It suffices to reduce the volume so as to reduce the heat capacity and to provide the rigidity that does not cause extreme distortion. Further, the length of the arm 4a is the length including the arm and the boat in the above-described embodiment, but the pushing amount of the boat 1a is the same, so the substantial dimension of the pushing arm is the same as that in the above-described embodiment. It can be as short as the form.

FIGS. 5 (a) and 5 (b) are graphs showing the temperature change in the boat when the wafer is loaded and unloaded by the wafer loading / unloading apparatus according to the conventional example and the embodiment of the present invention. By the way, the change in the furnace temperature by the conventional example and the wafer loading / unloading apparatus of the embodiment of the present invention was examined.
As a result, as shown in FIG. 5 (a), the temperature change at the time of entering the furnace is small in the case of one embodiment and the slide rod type which is the conventional example 1, and in the case of other embodiments. The temperature change is large. In the case of the conventional soft landing method, the change is large as expected. This is the difference in heat capacity depending on the wall thickness of the arm due to the strength of the arm.

Further, FIG. 5 (b) shows the temperature change at the time of exiting the furnace, but in the case of another embodiment of the present invention, there is no temperature change because only the arm staying in the furnace core tube is pulled out.
Further, in the case of one embodiment, a slight temperature decrease was recognized because the arm was inserted into the furnace core tube to take out the boat. In the case of the conventional soft landing method, the heat capacity of the arm was large and the temperature drop was remarkable.

[0020]

As described above, according to the present invention, as a boat moving mechanism for loading and unloading a boat, one rail having a smooth surface and a surface bulging in a circular shape and one wheel traveling on this rail are provided. By providing the wheels, it is possible to prevent the wheels from scraping the rails or stagnation of foreign substances on the rails, and as a result, it is possible to minimize the generation of particles due to the loading and unloading of the boat, resulting in defects in the quality of processed wafers. There is an effect that it can be lost.

Further, the wafer as a substrate and the total load of the boat are provided with wheels on the front end side of the boat and two legs supporting the rear end side of the boat, and the role of merely pushing or pulling the boat. Or a bar with high rigidity to support the front wheel and the rear end arm of the boat is provided outside the furnace to make the arm double-supported, and to move in and out of the furnace. The rigidity of each arm can be reduced, the wall thickness and volume of the arm itself can be reduced to reduce the heat capacity, the endothermic elements are reduced, the temperature recovery characteristics after the diffusion boat is not deteriorated, and the processing time due to the temperature decrease This has the effect of avoiding delays.

Furthermore, the arm itself can be made lighter in weight, and the bending moment applied to the moving mechanism for fixing and supporting the arm can be made smaller, so that the size can be reduced without increasing the longitudinal space in front of the furnace and the floor area can be increased. There is an effect that can be used for. By precisely finishing the outer shape of the rail with good flatness, it is possible to ensure the straightness of the boat at the time of entering and leaving the boat, and to maintain the levelness of the boat. As a result, there is an effect that a complicated adjustment work for changing the board mounting amount on the boat becomes unnecessary.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view for explaining a wafer loading / unloading device according to an embodiment of the present invention.

FIG. 2 is a partial perspective view showing the furnace core tube of FIG. 1 in an extracted manner.

3A to 3D are schematic cross-sectional views showing an operation sequence of the wafer loading / unloading device of FIG.

FIG. 4 is a schematic cross-sectional view for explaining a wafer loading / unloading device according to another embodiment of the present invention.

FIG. 5 is a graph showing temperature changes in the furnace when the boat is loaded and unloaded by the wafer loading / unloading device according to the conventional example and the embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view for explaining a wafer loading / unloading device according to a conventional example.

FIG. 7 is a schematic cross-sectional view for explaining a wafer loading / unloading device according to another conventional example.

[Explanation of symbols]

 1,1a, 11,11a Boat 2,13 Wheel 3,9a Foot 4,4a Arm 5 Rail 6,6a Moving mechanism 7 Boat receiver 8 Handle 9 Opening 10 Core tube 8 Heater 12 Scavenger 14 Slide rod 15 Guide mechanism Part 17 Fork 18 Wafer

Claims (3)

[Claims] 1. A rail having a boat receiver extending outward from the bottom of the opening at one end and extending horizontally in a horizontally arranged furnace core tube across the boat receiver, and a wafer. A plurality of boats are arranged side by side in the longitudinal direction, one wheel on the tip side of the boat that travels on the rails with the boat, and the unicycle travels to move the boat to the core. A wafer loading / unloading device, comprising: an arm that moves in and out of a tube and a moving mechanism that moves the arm. 2. A connecting mechanism by which the arm can be attached to and detached from a rear end of the boat, and the connecting mechanism removes the arm from the boat and places the arm on the bottom portion of the furnace core tube or the boat receiving portion. The wafer loading / unloading apparatus according to claim 1, further comprising: two foot members that support the boat with the wheels at three points. 3. The wafer loading / unloading apparatus according to claim 1, wherein said arm mounts said boat and mounts said wheel.