JP2829367B2 - Wafer transfer method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wafer transfer method, and more particularly to a wafer transfer method in a vertical diffusion CVD apparatus which is one of semiconductor manufacturing apparatuses.

[0002]

2. Description of the Related Art One of semiconductor manufacturing apparatuses is a vertical CVD apparatus.

As described in Japanese Utility Model Application No. 63-17237, wafers loaded in a cassette are transferred to a boat by a transfer machine, and the boat is loaded into a reaction chamber in a furnace. , Heat reaction to form a reaction film on the wafer surface.

[0004] Processing of a wafer by a diffusion CVD apparatus is as follows.
Due to its nature, it must always be performed under the same conditions (processing temperature, reaction gas flow rate supplied into the reaction chamber, reaction chamber pressure, number of wafers on the boat, arrangement, etc.). Therefore, the arrangement and the number of wafers on the boat when performing the specified processing as the diffusion CVD apparatus must always be the same as long as the same processing is performed.

However, the total number of wafers processed by the diffusion CVD apparatus often decreases and fluctuates as processing proceeds, due to processing defects and the like. Therefore, in order to arrange the wafers on the boat in a predetermined arrangement, it is necessary to replenish the reduced wafers.

In a conventional wafer transfer machine, transfer is not performed in response to a change in the total number of wafers.
Before the transfer of wafers to the boat, the operator checks the number of wafers in the cassette, and if there is a shortage with respect to the predetermined number, the operator manually refills the cassette with the insufficient number of wafers.

[0007] Alternatively, even if the actual number of wafers is insufficient with respect to the predetermined number of wafers, the number of wafers is not replenished, and the number of wafers is left as it is on the boat without any gap from above to below. Transfer the wafers and change the arrangement of the wafers on the boat under other conditions (reaction gas flow rate,
(Processing temperature, processing time, etc.).

[0008]

However, in the method of replenishing a shortage of wafers by manual labor, manual labor for replenishing wafers is required, which is inefficient and copes with automation (unmanned) of processing steps. could not.

Further, in a method in which another processing condition is changed and the same processing is performed without replenishing the wafer, it is very difficult to determine the amount of change in various conditions. Requires many trial processes. Therefore, when the number of processed wafers fluctuates frequently, a large amount of time is required to determine the change amount, the work amount of the worker increases, and a burden is imposed on the worker, and also in terms of product productivity. There was a problem.

The present invention has been made in view of the above circumstances, and has as its object to provide a wafer transfer method capable of transferring a wafer while replenishing the change when the number of wafers changes.

[0011]

According to the present invention, there is provided a reaction chamber having a plurality of cassettes loaded with wafers and a boat holding a plurality of wafers at predetermined intervals in a direction perpendicular to the horizontal plane of the wafers. A method of transferring a wafer from a cassette to a boat in an apparatus for performing a predetermined treatment on a wafer by supplying a reaction gas into the reaction chamber, heating the wafer, and charging the boat holding the wafer into the reaction chamber, Regarding the wafer transfer method of transferring the wafer while refilling the dummy wafer for the product wafer shortage on the boat so that the product wafer and monitor wafer in the boat are arranged in a preset manner. Product wafers and monitor wafers are arranged in the same boat. While supplemented with Me wafer is intended according to the wafer transfer method of performing transfer. Therefore, regardless of the state of the wafers loaded in the cassette, the wafers are transferred to the boat so as to always have the set arrangement.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a vertical diffusion CV in which the present invention is implemented.
It is an internal perspective view of D apparatus.

In FIG. 1, reference numeral 1 denotes a heater for heating a wafer in a reaction chamber 8. Reference numeral 4 denotes a boat elevator for loading and unloading the boat 3 on which the wafers 2 are loaded into the reaction chamber 8, reference numeral 5 denotes a wafer transfer machine for transferring the wafers 2 from the cassette to the boat 3 and from the boat 3 to the cassette, and reference numeral 6 denotes a wafer transfer machine. A furnace port shutter for preventing radiant heat and air from being entrapped from the furnace port 9 during the transfer of the wafer 2, and a cassette stocker 7 for storing cassettes in multiple rows and multiple rows (two rows and four rows in the figure).

The cassette stocker 7 is movable in a horizontal direction with respect to the transfer machine 5 from a cylinder 17 to be described later. The transfer machine 5 has a wafer chuck 10 for sucking the wafer 2 by vacuum. The wafer chuck 10
It has a horizontal moving mechanism 11 for moving the device in the horizontal direction, an elevating mechanism 12 for elevating and lowering, and a rotating mechanism 13 for rotating.

The wafer chuck 10 has a required number (five in this embodiment) of suction plates 10a, 10b,
10c, 10d, and 10e.
a, 10b, 10c, 10d, and 10e are independently operated solenoid valves 30a, 30b, 30c, 30d,
It is connected to a vacuum source (not shown) via 30e.

A wafer sensor 15 for detecting the presence or absence of the wafer 2 is provided on an elevating table 18 of the elevating mechanism 12 in which the wafer chuck 10 is provided.
Further, a wafer reference position sensor 16 for detecting a reference point when a wafer is detected by the wafer detection sensor 15 includes a receiving unit 16a and a transmitting unit 16b. The receiving unit 16a is provided on the elevation table 18, and the transmitting unit 16b Are provided for each cassette stocker shelf of the cassette stocker 7 and below each shelf.

The elevating table 18 is provided with the elevating mechanism 12
Of the lifting motor 20
The lifting screw 19 is connected with the lifting screw 19 and is moved up and down by the rotation of the lifting screw 19 by the lifting motor 20. An encoder 21 is attached to the lift motor 20, and the rotation speed of the lift motor 20, that is, the lift distance and position of the lift table 18 are detected by the encoder 21.

Although not shown, the horizontal movement mechanism 11 is adapted to horizontally drive the wafer chuck 10 by means of a screw / nut mechanism. A slide motor 22 for driving the screw and a rotation amount of the slide motor are provided. That is, the encoder 2 for detecting the movement amount of the wafer chuck
Three.

The rotation mechanism 13 also includes a rotation motor 24 for rotating the wafer chuck 10 and an encoder 25 for detecting the rotation angle of the wafer chuck 10, although not shown in detail.

The boat elevator 4 also has an elevator motor 26 and an encoder 27 for detecting the amount of elevation.

The furnace port shutter 6 is driven by a cylinder 28, which operates by a solenoid valve 29.
Non-operation is selected, and operation or non-operation of the cylinder 17 of the cassette stocker 7 is selected by the solenoid valve 31.

Hereinafter, the outline of the wafer transfer operation will be described.

The cassette to be transferred is selected by moving the cassette stocker 7 and moving the wafer chuck 10 up and down. Then, the rotating mechanism 13 rotates the wafer chuck 10 so that the wafer chuck 10 is in the wafer unloading position.

The wafer 2 is taken out of the cassette and transferred to the boat 3 by the cooperation of the wafer chuck release of the wafer chuck 10, the horizontal movement mechanism 11, the elevation movement mechanism 12, and the rotation movement mechanism 13.

When the wafer transfer to the boat 3 is completed,
The boat 3 is loaded into the reaction chamber 8 by the load / unload elevator 4 and the CVD process of the wafer 2 is performed.

Cassette 14 for wafer 2 after CVD processing
Transfer to the side is performed by the reverse operation.

Next, a control device for performing a wafer transfer operation will be described.

In FIG. 3, reference numeral 32 denotes a main control unit, and 33 denotes an operation unit.
6 and sensors (for example, pressure sensors) 34a, 34 for detecting the operating states of the solenoid valves 30a, 30b, 30c, 30d, 30e of the suction plate.
b, 34c, 34d, 34e, a sensor (for example, a proximity sensor) 35 for detecting the open / close state of the shutter 6, and a sensor (for example, a proximity sensor) for detecting the position of the cassette stocker 7
The detection signals from 36 are input respectively.

The main controller 32 is connected to a motor controller 38, 39, 40, 41 and a wafer sensor controller 42 via a communication controller 37, and the motor controller 38, 39, 40, 41 is connected to the motor controller 38, 39, 40, 41. Lifting motor 20, slide motor 22, rotation motor 24,
The elevator motor 26 is connected, and the wafer detection sensor 15 is connected to the wafer sensor controller 42.

Further, the motor controllers 38, 3
The encoders 21, 23, 23 and 9,
Detection signals from 25 and 27 are input.

The main control unit 32 includes drivers 43a, 43b, 43c, 43d, 43e of solenoid valves 30a, 30b, 30c, 30d, 30e for suction and plates, and solenoid valves 31, 27 for operating the cylinders 17, 28. Drivers 44 and 45 for driving the drive 29 are connected.

Referring to FIG. 4, an outline of the configuration of the main control unit 32 will be described.

The main control unit 32 mainly includes an input / output control unit 46 to which the operation unit 33 is connected, and the solenoid valve drivers 43a and 43
3b, 43c, 43d, 43e, 44, 45 are connected to an electromagnetic valve control unit 47, a transfer control execution unit 48 to which the communication control unit 37 is connected, a processor 49, a storage unit 50,
It comprises a wafer arrangement parameter setting section 51 and a transfer operation parameter creation section 52.

Hereinafter, the transfer control operation will be described with reference to FIG.

As shown in FIG. 5, the arrangement of wafers to be loaded in the boat 3 in a certain CVD process is such that the upper side dummy wafer group S. D (10), monitor wafer M1 (1), product wafer group P1 (25)
Wafer), monitor wafer M2 (1 wafer), product wafer group P
2 (25 wafers), monitor wafer M3 (1 wafer), product wafer group P3 (25 wafers), monitor wafer M4 (1 wafer),
Product wafer group P4 (25 wafers), monitor wafer M5
(1), lower side dummy wafer group S. D (10 pieces)
And the product wafer transferred from the previous process to each cassette stored in the cassette stocker 7 is P1 = 20.
Wafers, P2 = 25 wafers, P3 = 18 wafers, P4 = 25 wafers, and other cassettes with side dummy wafers S.S. D = 20
Wafers, monitor wafers M = 5, refill dummy wafers F.
D1 = 21, F.I. It is assumed that D2 = 21 is loaded.

As for the arrangement of the wafers on the boat, the number of product wafers, the position of the monitor wafer, and the like are input from the operation unit 33 to the main control unit 32. The input wafer arrangement condition is
After signal processing by the input / output control unit 46, the processor 49
Through the wafer arrangement parameter setting unit 51
Thus, a wafer array for performing transfer control is created, and this array is stored in the storage unit 50. The wafer arrangement parameter setting unit 51 also checks whether or not the input wafer arrangement condition is reasonable for performing the transfer operation.

Next, the operation unit 33 instructs the start of wafer transfer.

When an instruction to start transfer is given, the wafer detection sensor 15 is caused to face a predetermined row of the cassette stocker 7, for example, row I. Whether or not the wafer detection sensor 15 faces row I is determined by a signal from the sensor 36. With the lifting table 18 at the lowest position, the lifting motor 20
Is driven to raise the lifting table 18 via the lifting screw 19.

The wafer detection sensor 15 is a non-contact type sensor such as an ultrasonic sensor and an optical sensor, and emits a measurement medium to the end face of the wafer and detects the presence or absence of the wafer by reflection from the end face.

The amount of movement of the wafer detection sensor 15, that is, the amount of movement of the lifting table 18, is detected by the encoder 21, and the wafer reference position sensor 1 is provided for each cassette.
6, the reference position is detected, and it is detected how many wafers are in each cassette and where the wafers are missing.

The detection of the number of wafers and the measurement of the number of wafers are also performed for the II row. The horizontal movement of the cassette stocker 7 is performed by operating the solenoid valve 31 via the driver 44 and driving the cylinder 17 after the completion of the counting of the I rows. Whether or not the cassette stocker 7 has reached the position of the II row with respect to the wafer detection sensor 15 is detected by the sensor 36.

The counting of the number of wafers in row II is performed in the same procedure as described above.

When the counting of the number of wafers is completed, the counting result is input to the moving operation parameter creating section 52 via the input / output controller 46 and the processor 49. In the transfer operation parameter creation section 52, based on the wafer arrangement parameters and the number of wafers counted, if there is a shortage in the product wafer, which cassette should be filled with the refill dummy wafer, or the transfer order of the wafers can be determined. Decide,
The transfer operation parameters are created, and the transfer operation parameters are input and stored in the storage unit 50.

When the creation of the transfer operation parameters is completed,
The wafer transfer operation is performed according to the transfer operation parameters.

The wafer transfer operation is performed by a transfer control execution unit 48.
Done through. Since the transfer operation of one wafer has been described above, the description is omitted here. However, the transfer operation is performed based on the transfer operation sequence input to the storage unit 50 via the processor 49 in advance, and The transfer procedure in which the arrangement is determined by the wafer arrangement parameters is performed based on the transfer operation parameters.

The communication control section 37 judges the signal output from the main control section 32 and issues a command signal to a motor controller of a motor to be operated. Also, the main control unit 32
Is the case where the fraction processing of the wafer is performed (4 in this embodiment).
When transferring less than two wafers), the solenoid valve 30a,
Select one of 30b, 30c, 30d, 30e
Corresponding drivers 43a, 43b, 43c, 43d, 4
3e, solenoid valves 30a, 30b, 30c, 30d,
30e is operated to suck the wafer to the suction plate.

Thus, even if there is a shortage of wafers in the pre-transfer cassette, the transfer operation to the boat is performed so that a desired wafer arrangement is achieved without manually replenishing wafers.

The result of counting the number of wafers in which cassette and how many wafers are insufficient, the progress of transfer, and the like are displayed on the operation unit.

In the above embodiment, the number of wafers is automatically measured. However, the number of wafers may be counted by an operator and input via the operation unit 33.

[0051]

As described above, according to the present invention, diffusion and
Even if the product wafer supplied to the CVD equipment fluctuates,
There is no need to manually replenish the shortage of wafers, and wafers are transferred so that the desired arrangement of wafers is achieved, so wafer transfer efficiency can be greatly improved and manual work during the process is omitted. As a result, it is possible to achieve excellent effects such as stabilization of processes in a semiconductor manufacturing factory, stabilization of product quality, promotion of automation, and reduction of dust in the factory.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an outline of a vertical diffusion device.

FIG. 2 is an explanatory diagram of a wafer detection sensor.

FIG. 3 is a block diagram showing an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a main control unit.

FIG. 5 is an explanatory diagram of wafer arrangement and wafer transfer.

[Explanation of symbols]

 2 Wafer 3 Boat 5 Wafer transfer machine 7 Cassette stocker 14 Cassette 15 Wafer detection sensor 32 Main control unit 49 Processor 51 Wafer arrangement parameter setting unit 52 Transfer operation parameter creation unit

Claims (2)

(57) [Claims] 1. A boat having a plurality of cassettes loaded with wafers and holding a plurality of wafers at predetermined intervals in a direction perpendicular to a horizontal plane of the wafers, wherein the boat holding the wafers is placed in a reaction chamber. In the method of transferring a wafer from a cassette to the boat in an apparatus for charging, supplying a reaction gas into the reaction chamber, heating and performing a predetermined process on the wafer, a predetermined operation in the boat is performed. Product c
A wafer transfer method characterized in that a wafer is transferred while replenishing a shortage of product wafers on a boat with dummy wafers so that wafers and monitor wafers are arranged. 2. A shortage of product wafers on the boat is replenished with dummy wafers without changing the positions of the preset monitor wafers so that a predetermined arrangement of the product wafers and monitor wafers in the boat is obtained. 2. The wafer transfer method according to claim 1 , wherein the transfer is performed.