JPH0831510B2 - Wafer transfer method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to an improvement of a wafer transfer method for transferring a group of a plurality of wafers stored in a storage jig toward a boat.

(Prior Art) Generally, in a semiconductor manufacturing apparatus, a wafer group mounted on a boat made of quartz or the like is loaded into a heat treatment furnace,
By carrying it out, the diffusion processing for a large number of wafers is collectively performed.

Therefore, when performing such a thermal diffusion process on a wafer, a storage jig in which a plurality of wafer groups are aligned and stored,
For example, it is necessary to perform a loading operation in which a wafer group is taken out from a cassette or the like and placed on a boat.
Further, after the diffusion process is completed, it is necessary to carry out an unloading operation for storing the wafer group placed on the boat in the original cassette again.

The semiconductor device is provided with a wafer transfer device that performs such loading and unloading operations.
This transfer device transfers a group of a plurality of wafers, which are aligned and stored in a cassette, to a predetermined upper position by using a wafer push-up device, and transfers them to a holding means called a chuck. Then, the chuck performs a loading operation of holding the transferred wafer group from both sides thereof and transporting the wafer group to the boat. Since a plurality of storage grooves are provided on the boat at regular intervals, the loaded wafers are aligned and stored along the grooves at regular intervals.

Such a loading operation is repeatedly performed on a plurality of cassettes placed on the cassette floor, so that a group of wafers stored in the plurality of cassettes are sequentially placed on the boat. .

Incidentally, the unloading work for returning the wafer after the diffusion process to the cassette is performed in the completely reverse procedure of the above-mentioned loading work.

By the way, 3 to 10 wafers are placed on such a boat.
It is preferable to incline in a fixed direction with respect to the vertical direction, preferably 3 to 5 degrees.

This is because it is necessary to keep the wafers placed on the boat at regular intervals in order to perform a diffusion process on the wafers and form a uniform film on the surface. This is because it is empirically known that good thermal diffusion processing can be performed by inclining a wafer tilted in the inflow direction by a predetermined angle in the same direction in order to allow uniform inflow.

Further, the storage groove provided in such a boat is normally oriented in the vertical direction, and its width is formed to be slightly larger than the thickness of the wafer. For this reason, even if the wafers are simply transferred onto the boat, each wafer randomly tilts forward and backward due to the play between the wafers, which causes a problem that the wafers are chipped. However, if the wafers are tilted in one direction from the beginning and loaded, such chipping between the wafers can be prevented.

In particular, when the boat is made of a material such as quartz and used for a long period of time, the boat is somewhat deformed and the pitch of the storage grooves becomes non-uniform. However, as described above, when the wafer is loaded with being tilted in one direction, the influence of such deformation of the boat itself is small, and from this aspect, the wafer can be satisfactorily subjected to thermal diffusion processing.

By the way, as a technique for loading a wafer on a boat while tilting the wafer in a certain direction at a predetermined angle, conventionally, there has been proposed a device in which the boat itself is tilted at a predetermined angle and installed in advance and the wafer is loaded into the boat. (Actual development number 61-136543).

However, in this case, the boat itself must be returned to a horizontal position before it is loaded into the heat treatment furnace.
Therefore, it is necessary to provide the angle adjusting mechanism and various mechanisms associated therewith, which causes a problem that the entire apparatus becomes complicated.

In particular, since a large number of wafers such as 100 and 200 are placed on the boat, considering the present situation where the boat is carried into the heat treatment furnace and the large number of wafers are collectively subjected to thermal diffusion processing, However, moving the boat itself in which the wafers are stored and mounted is extremely problematic.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and to easily and surely incline a wafer onto a boat at a predetermined angle without loading the wafer itself and to load and unload a wafer. It is to provide a transfer method.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a wafer storage device that is inclined at a predetermined angle from a first storage container in which a plurality of wafers are vertically erected. When the wafers are automatically transferred to the second storage container in the groove array, the first storage container is placed with the predetermined angle tilted, and the upper transfer means is used to remove the wafer group from the first storage container. The wafer group is transferred to the upper predetermined position while being tilted, and the transferred wafer group is held while tilted by the holding means, and is transferred to the second storage container to transfer the wafer group onto the second storage container. It is characterized in that it is placed at a predetermined angle.

(Operation) According to the present invention, the first storage container in which the wafer group is aligned and stored on the floor has a predetermined angle θ, preferably 3 to 10 degrees.
More preferably, it is placed with an inclination of 3 to 5 degrees.

Then, in this state, a group of a plurality of wafers that are aligned and stored in the first storage container are transferred to the second storage container while keeping the inclination angle θ by using the upper transfer means and the holding means. .

Therefore, such a wafer transfer operation is performed on the plurality of first storage containers placed on the floor at a predetermined angle θ.
That is, by repeating the loading operation, it is possible to incline a plurality of wafer groups from each first storage container in the same direction by the same angle θ and load them into the second storage container.

In particular, according to the present invention, a large amount of wafers can be loaded in a state tilted by a predetermined angle θ in the same direction without tilting the second storage container itself, which makes the entire apparatus extremely simple. In addition, it is possible to minimize the movement of the second storage container that stores a large amount of wafers.

(Embodiment) Next, a preferred embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 2, the wafer transfer apparatus of this embodiment is
A cassette stage 12 for mounting a plurality of cassettes 10 (first storage container) and a boat stage 22 provided with a boat 20 (second storage container) are arranged substantially linearly adjacent to each other, A moving groove 32 along which the chuck device 30 moves is provided along each of these stages 12 and 22.

Further, the inside of the apparatus main body 100 is formed in a substantially hollow shape, and a pair of rails are provided on the inner bottom surface as shown in FIG.
40, 40 are provided along this rail 40 (the above-mentioned moving groove
A slider 42 is formed to move (along 32). The slider 42 has its slide position controlled by rotationally driving a ball screw 44 using a motor 46 as shown in FIG. And on this slider 42,
The chuck device 30 and the wafer lifting device 50 described above are arranged adjacent to each other.

Then, using both of these devices 30 and 50, the wafer portion is taken out from the cassette 10 and transferred to the boat 20.

In this embodiment, the cassette stage 12 has a second
As shown in the figure, a plurality of table insertion openings 14 are provided at regular intervals, and in this embodiment, the wafer w is placed on the opening edge portion of the insertion opening 14 with a predetermined angle θ inclined in the same direction. The first feature is that the cassette mounting portion 16 is provided.

Here, the inclination angle θ is set in a range of 3 degrees to 10 degrees, preferably 3 degrees to 5 degrees.

Normally, the bottom surface of the cassette 10 mounted on the mounting portion 16 is formed as shown in FIG. 2, and the vertical grooves 10a for storing and holding the wafer are formed on the inner surfaces of both walls. It is provided at regular intervals.

In a semiconductor device, the wafer group stored in the cassette 10 is often handled as one unit. Therefore, the storage grooves are normally provided at 25 at regular intervals, and are formed so that a maximum of 25 wafers can be stored in the cassette 10 as a unit.

As described above, in the present embodiment, the wafer w is vertically housed in the cassette 10, and the cassette 10 is mounted on the mounting portion 16 with an angle θ. Therefore, on the cassette stage 12, the wafer w accommodated in the cassette 10 is tilted leftward by θ as shown in FIG.

The feature of the present invention is that the wafer w stored in the cassette 10 is taken out with its inclination θ and transferred to the boat 20 so that the wafer group is loaded on the boat 20 with the same inclination θ in the same direction. To do.

In this embodiment, such loading work is
The wafer lifting device 50 and the chuck device 30 are used.

The wafer lifting device 50 is a slider so that it can be located below the table insertion opening 14 of the cassette stage 12.
It is mounted on the table 42, and as shown in FIG. 3, the table 52 is formed so as to be movable upward of the stage 12 through the insertion port 14.

On the surface of the table 52, the storage groove for the cassette 10 is provided.
Twenty-five wafer support grooves 54 are formed in accordance with the pitch interval of 10a. Therefore, by moving the table 52 upward through the insertion port 14 as shown in FIG. 3, the lower end of the wafer w stored in the cassette 10 can be supported and transferred upward.

The second feature of the embodiment is that, as shown in FIG. 4, the wafer push-up device 50 is formed so as to move up and down along a trajectory in which the table 52 is tilted by an angle θ with respect to the vertical direction. As a result, the table 52 can transfer the wafer w stored in the cassette 10 upward while tilting the wafer w by a constant angle θ.

Then, the wafer w transferred to the predetermined upper position is held by using the chuck device 30 functioning as a wafer holding means, and transferred to the boat 20 via a predetermined moving path.

In this embodiment, the chuck device 30 is mounted on the slider 42 in a state of being tilted by an angle θ along the vertical direction as shown in FIG. 5, and the head 34 provided on the slider 42 is mounted only by θ. It is formed so as to be able to move upward along an inclined movement trajectory.

As shown in FIG. 3, a pair of chucks 38, 38 are attached to the head 34 via an arm 36, and the chucks 38, 38 are driven to open and close in the arrow direction shown in FIG. Is formed.

The third feature of the embodiment is that, on the inner surfaces of the pair of chucks 38, 38, storage grooves 38a formed at the same pitch as the grooves 10a provided in the cassette 10 described above are provided in the vertical direction as shown in FIG. It is provided that it is inclined by an angle θ with respect to.

As shown in FIGS. 8 and 9, the storage groove 38a is provided with a pair of guide surfaces 26, 26 on both sides of the opening end thereof. The wafer w is formed so as to be accommodated in the groove via the groove.

Therefore, by using the above-mentioned wafer push-up device 50, the wafer w pushed up and transferred to a predetermined upper position as shown in FIG. 6 (a) is held from both sides thereof as shown in FIG. 6 (b). As a result, the wafer w can be smoothly transferred from the wafer push-up device 50 to the chuck device 30.

At this time, as described above, the pair of chucks 38, 38
Since the storage groove 38a provided on the wafer is inclined at an angle θ with respect to the vertical direction, the chuck device 30 moves the wafer w at the same inclination θ as when the wafer w is stored in the cassette 10. It will be held.

FIG. 1 (b) shows a state at the time of this delivery, and after the delivery is completed, for example, by moving the table 52 downward or moving the chuck 38 upward, the left side in the figure. The wafers are sequentially caught in the storage groove 38a of the chuck 38, and the surface connecting the upper end surfaces of all the wafers w becomes horizontal.

Then, the ball screw 44 is rotationally driven, and the slider 42 moves to a predetermined position on the boat stage 22. At this time,
The chuck device 30 moves the wafer to a predetermined position above the boat 20 along the movement locus 200 shown in FIG. 1C, and then lowers the head 34. Then, as shown in FIG. 7, when the wafer w descends near the boat 20, the chucks 38, 38 are opened in the direction of the arrow in the figure, and the wafer w is tilted leftward in FIG. 1 by a predetermined angle θ. Load on boat 20.

In the present embodiment, the boat 20 is formed so as to support the wafer w by using four support rods 20a provided along the longitudinal direction thereof. And this rod
As shown in FIG. 2, a plurality of wafer accommodating grooves 24 that match the pitch intervals of the cassette 10 are provided on the inner surface of 20a.
Moreover, like the groove 38a shown in FIG. 8, the groove 26 is formed so as to be inclined by a predetermined angle θ with respect to the vertical direction. Therefore, the wafer w, which is transferred while being inclined by a predetermined angle θ by using the chuck device 30 described above, can be stored on the boat 20 while maintaining the inclination state θ.

Further, as shown in FIG. 9, the storage groove 24 is provided with a pair of guide surfaces 26, 26, and even if the transfer position of the wafer w is slightly deviated, the wafer w is inserted into the groove via the guide surface 26. Is formed so that it can be stored.

In this embodiment, the groove 10a of the cassette 10 and the groove 38a provided in the chuck 38 are formed in substantially the same manner as the groove 24 shown in FIGS. 8 and 9.

The wafer transfer apparatus of this embodiment is formed as described above. Next, the wafer transfer operation performed using this apparatus will be described.

In this embodiment, the cassette containing the wafer w is mounted on the cassette mounting portion 16 on the cassette stage 12 with a predetermined angle θ, as shown in FIG.

As a result, each wafer w stored in the cassette 10 is tilted to the left in the figure by θ with respect to the vertical plane.

In this state, move the slider 42 to move the chuck lifting device.
The position of the table 52 of the table 50 is controlled so as to be below the predetermined table insertion opening 14 of the cassette stage 12.

Then, the wafer push-up device 50 moves the table 52 upward through the cassette insertion port 14 as shown in FIG. 1 (b), whereby the plurality of wafer groups housed in the cassette 10 are angled. It is transferred to a predetermined upper position while being inclined by θ.

When the wafer w is transferred to a predetermined position,
As shown in FIG. 6, the chucks 38, 38 are closed, and a group of a plurality of wafers are held along a groove 38a provided in the inner surface thereof while being inclined to the left in FIG. 1 by a predetermined angle θ. .
This completes the delivery of the wafer w from the table 52 to the chuck 38.

After such delivery, the wafer push-up device 50 retracts the table 52 to the back surface side of the stage 12. As a result, the wafer moves downward by its own weight, and the wafer group is held by the chucks 38, 38 so that the line connecting the upper ends of the wafer group becomes horizontal.

In this way, when the wafer group is clamped by the chuck 38 and the table 52 is retracted to the lower side of the cassette stage 12, the apparatus of the embodiment, as shown in FIG. Move the chuck 38 along
The wafer group is transferred to a predetermined position above the boat 20 and the chucks 38, 38 are opened as shown in FIG. As a result, the wafer group stored in the cassette mounting table 16 is transferred to the boat 20 while maintaining the inclination θ with respect to the vertical direction, and mounted on the boat 20 in that state.

Particularly, in this embodiment, the storage grooves 24 provided on both sides of the boat 20 are formed by inclining by a predetermined angle θ in the vertical direction as shown in FIG. Therefore, as described above, the wafer group transferred while being inclined by the angle θ can be reliably placed on the boat 20 while maintaining the inclined state.

In the present embodiment, such a boat transfer operation is
All cassettes 10 mounted on cassette stage 12
Repeat for. Therefore, the wafer group stored in each of the cassettes 10 is successively loaded onto the boat 20 in a state of being inclined leftward in the drawing by a predetermined angle θ.

As described above, according to the present invention, the wafer group can be loaded onto the boat 20 in a state in which the wafer group is tilted in the fixed direction by the angle θ without using any special device.

Particularly, according to the present invention, after the loading of the wafer w onto the boat 20 is completed, it is not necessary to control the tilt of the boat 20 itself as in the conventional device, and therefore, the movement of the boat loaded with a large amount of wafers is required. It can be minimized, which is extremely suitable for manufacturing semiconductors.

In the present invention, the wafer w for which the diffusion process has been completed
The operation of unloading the cartridge from the boat 20 to the corresponding cassette 10 may be carried out in the completely reverse order of the loading operation.

Further, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention.

For example, in the embodiment, the head 34 is used as a holding means.
Although the case where the chucks 38, 38 that move up and down together with the chucks 38, 38 are used as an example, the present invention is not limited to this. For example, the chucks 38, 38 may be provided on the robot arm to hold the wafer.

[Effects of the Invention] As described above, according to the present invention, the first storage container in which a plurality of wafer groups are aligned and stored, for example, the storage jig, is placed on the floor at a predetermined angle, and the first storage container is mounted. On the second storage container, the wafer group stored in the first storage container is transferred to the second storage container, for example, on the boat by using the upper transfer means and the holding means while keeping the inclination angle. Moreover, the wafer group can be loaded while tilted in the same direction by a predetermined angle, and the loading operation can be performed using a simple device.

Particularly, according to the present invention, after the wafer group is loaded on the second storage container, for example, the boat, the movement of the boat can be minimized. Therefore, the boat itself on which a large amount of wafers are loaded is moved. This makes it extremely suitable as a wafer transfer method for a semiconductor manufacturing apparatus without various inconveniences.

[Brief description of drawings]

FIG. 1 is an operation explanatory view of a wafer transfer method according to the present invention. FIG. 1A is an explanatory view showing a state in which a cassette accommodating a wafer is placed on a cassette stage, and FIG. 1B is a wafer. FIG. 2C is an explanatory view showing a state where the wafer group is taken out from the cassette by using the push-up device, FIG. 2C is an explanatory view showing a state where the wafer group is being transferred by using a chuck, and FIG. FIG. 3 is an external perspective view of the transfer device, FIG. 3 is an explanatory view showing a state where the wafer is taken out of the cassette by using the wafer transfer device shown in FIG. 2, and FIG. 4 is a sectional view taken along line IV-IV of FIG. FIG. 6 is a side view of FIG. 3, and FIG. 6 is an explanatory view of the operation of holding the wafer by using the chuck. FIG. 6A is a state in which the chuck is open, and FIG. Fig. 7 shows the state in which the wafer is transferred and the transferred wafer is placed on the boat. FIG. 8 is a side view of a storage groove provided on a side surface of a boat, a chuck, and a cassette, and FIG. 9 is a cross-sectional view taken along line IX-IX of the groove shown in FIG. 10 ... Cassette 10a, 24 ... Storage groove 20 ... Boat 30 ... Chuck device 38 ... Chuck 50 ... Wafer lifting device w ... Wafer

Claims (1)

[Claims] 1. When automatically transferring wafers from a first storage container in which a plurality of wafers are vertically set up to a second storage container in a wafer storage groove row inclined by a predetermined angle, The storage container is tilted by the predetermined angle, and the upper transfer means is used to transfer the wafer group from the first storage container to the predetermined upper position while tilting the wafer group. A wafer transfer method comprising holding the wafer group on the second storage container by tilting the wafer group by a predetermined angle by holding the wafer group by transferring the wafer group to the second storage container.