JPH0727955B2 - Wafer transfer method, its control device, and semiconductor manufacturing device - Google Patents

Description

The present invention relates to a wafer transfer method in a vertical diffusion CVD apparatus which is one of semiconductor manufacturing apparatuses, a control apparatus therefor, and a semiconductor provided with the control apparatus. The present invention relates to a manufacturing device.

[Prior Art] One of semiconductor manufacturing apparatuses is a vertical CVD apparatus.

As shown in Japanese Patent Application No. 63-17237, this is because a wafer loaded in a cassette is transferred to a boat by a transfer machine, the boat is loaded into a reaction chamber in a furnace, and heating reaction is performed. The reaction film is also formed on the wafer surface.

Due to the nature of wafer processing by diffusion CVD equipment, the conditions are always the same (processing temperature, reaction gas flow rate supplied to reaction chamber, reaction chamber pressure, number of wafers on boat, arrangement, etc.)
Must be done in. Therefore, when performing a specified process which is a diffusion CVD apparatus, the arrangement and number of wafers on the boat must always be the same as long as the same process is performed.

However, the total number of wafers processed by the diffusion CVD apparatus often decreases and fluctuates due to processing defects and the like as the processing steps progress. Therefore, in order to arrange the wafers on the boat in a predetermined manner, the reduced amount of wafers must be replenished.

In the conventional wafer transfer machine, since it is not designed to transfer in response to the fluctuation of the total number of wafers, before confirming the wafer transfer to the boat, the operator confirms the number of wafers in the cassette, If there was a shortage of the specified number of wafers, the wafers of the shortage number were manually replenished in the cassette.

Alternatively, even if the actual number of wafers is insufficient with respect to the specified number, the wafers are not replenished, and the number of wafers is transferred as it is from the top to the bottom of the boat without any gap. Other conditions (reaction gas flow rate, processing temperature,
The processing time, etc.) was changed.

[Problems to be Solved by the Invention] However, in the method of replenishing a shortage of wafers by manual work, manpower for replenishing wafers is required,
It was inefficient and could not cope with automation of the processing process (unmanned).

In addition, it is very difficult to determine the change amount of various conditions in the method of performing the same process by changing other process conditions without replenishing the wafer. Trial processing is required. Therefore, when the number of processed wafers is frequently changed, it takes a lot of time to determine the change amount, the work amount of the worker is increased, the worker is burdened, and the productivity of the product is also increased. There was a problem.

In view of the above situation, the present invention provides a wafer transfer method and a controller therefor capable of transferring wafers while supplementing the fluctuation when the number of wafers changes, and a semiconductor manufacturing apparatus including the controller. It is the one we are trying to provide.

[Means for Solving the Problem] The present invention relates to a case where a wafer loaded in a plurality of cassettes by a transfer machine is transferred from a cassette to a boat that holds wafers in multiple stages and a preset boat is used. In order to achieve the above wafer arrangement, the shortage of wafers on the boat is characterized by performing transfer while supplementing with dummy wafers.

[Operation] The shortage of the wafer is obtained from the wafers loaded in the cassette and the wafer arrangement on the boat set in advance, and when there is a shortage, the shortage is replenished with dummy wafers for transfer. Therefore, regardless of the state of the wafers loaded in the cassette, the wafers are transferred to the boat so that the arrangement is always set.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an internal perspective view of a vertical diffusion CVD apparatus in which the present invention is implemented.

In FIG. 1, 1 is a heater for heating the wafer in the reaction chamber 8. 4 is a boat elevator for loading and unloading the boat 3 on which the wafer 2 is placed in the reaction chamber 8, 5 is a wafer transfer machine for transferring the wafer 2 from the cassette 3 to the boat 3 and from the boat 3 to the cassette, and 6 is A furnace opening shutter that prevents radiant heat from the furnace opening 9 and air from being entrained during the transfer of the wafer 2, and 7 is a cassette stocker that stores cassettes in multiple rows and multiple rows (two rows and four rows in the figure).

The cassette stocker 7 is movable in the horizontal direction with respect to the transfer machine 5 from a cylinder 17 described later, and the transfer machine 5
Is a wafer chuck 10 that attracts the wafer 2 by vacuum.
The wafer chuck 10 further includes a horizontal movement mechanism section 11 for moving the wafer chuck 10 in a horizontal direction, an elevation movement mechanism section 12 for raising and lowering the wafer chuck 10, and a rotation movement mechanism section 13 for rotating the wafer chuck 10.

The required number of wafer chucks 10 (5 in this embodiment)
Sheet) adsorption plates 10a, 10b, 10c, 10d, 10e, and each adsorption plate 10a, 10b, 10c, 10d, 10e is a solenoid valve 30a, 30b, 30c, 30d, 30e operated independently Via a vacuum source (not shown).

The lifting mechanism unit provided with the wafer chuck 10.
A wafer sensor 15 for detecting the presence or absence of the wafer 2 is provided on the lifting table 18 of 12. Wafer detection sensor
Wafer reference position sensor 16 for performing reference point detection when performing wafer detection by 15 is composed of a receiving unit 16a, a transmitting unit 16b, the receiving unit 16a is provided in the lifting table 18,
The transmitter 16b is provided for each cassette stocker shelf of the cassette stocker 7 and below each shelf.

The lifting table 18 is a lifting screw of the lifting mechanism unit 12.
It is screwed to 19 and is screwed to an elevating screw 19 connected to an elevating motor 20, and when the elevating motor 20 rotates the elevating screw 19, it is moved up and down. An encoder 21 is attached to the lift motor 20, and the encoder 21 detects the number of rotations of the lift motor 20, that is, the lift distance and position of the lift table 18.

Further, although not shown, the horizontal movement mechanism unit 11 is adapted to horizontally drive the wafer chuck 10 by a screw / nut mechanism, and the slide motor 22 for driving the screw, the rotation amount of the slide motor, that is, the wafer. It has an encoder 23 for detecting the amount of movement of the chuck.

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

Further, 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, and the cylinder 28 is selected to be operated or not operated by a solenoid valve 29.
Further, the cylinder 17 of the cassette stocker 7 can be operated or not operated by a solenoid valve 31.

The outline of the wafer transfer operation will be described below.

The cassette to be transferred is selected by moving the cassette stocker 7 and moving the wafer chuck 10 up and down, and then the wafer chuck 10 is rotated by the rotation mechanism 13 so that the wafer chuck 10 is in the wafer taking-out posture.

Wafer suction release of wafer chuck, horizontal movement mechanism 1
The wafer 2 is taken out of the cassette and transferred to the boat 3 by the cooperation of 1, the lifting mechanism 12, and the rotation 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 wafer 2 is subjected to the CVD process.

The transfer of the wafer 2 to the cassette 14 side after the CVD process is performed in the reverse operation to the above.

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

In FIG. 3, reference numeral 32 is a main control unit, 33 is an operation unit, and the main control unit
A detection signal from the wafer reference position sensor 16 is input to 32 and solenoid valves 30a, 30b, 30c, 30 of the suction plate are input.
Sensors (e.g., pressure sensors) 34a, 34b, 34c, 34d, 34e that detect the operating states of d and 30e, sensors (e.g., proximity sensors) 35 that detect the open / closed state of the shutter 6, and sensors that detect the position of the cassette stocker 7. Detection signals from (for example, a proximity sensor) 36 are input.

The main controller 32 includes a motor controller 38, 39, 40, 41 and a wafer sensor controller 42 via a communication controller 37.
Are respectively connected, and motor controllers 38, 39, 40, 4
The lift motor 20, slide motor 22, rotary motor 24, and elevator motor 26 are connected to 1, and the wafer detection sensor 15 is connected to the wafer sensor controller 42.

Further, detection signals from the encoders 21, 23, 25, 27 are input to the motor controllers 38, 39, 40, 41, 42.

The main control unit 32 is an electromagnetic valve for adsorption, a plate solenoid valve 30a, 30b,
Drivers 43a, 43b, 43c, 43d, 43e for 30c, 30d, 30e and drivers 44, 4 for driving solenoid valves 31, 29 for operating cylinders 17, 28
5 is connected.

An outline of the configuration of the main controller 32 will be described with reference to FIG.

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

The transfer control operation will be described below with reference to FIG.

As shown in FIG. 5, a boat 4 was used in a CVD process.
The array of wafers to be loaded in the upper side is from the upper side to the upper side dummy wafer group SD (10 wafers), monitor wafer M1 (1
Wafers, product wafer group P1 (25 wafers), monitor wafer M2
(1 wafer), product wafer group P2 (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 wafer), lower side dummy wafer group SD (10 wafers)
The number of product wafers passed 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, side dummy wafer SD = 20 wafers, monitor wafer M = 5 wafers, refill dummy wafers F.D1 = 21, F.D2 = Suppose 21 are loaded respectively.

With respect to the planned arrangement of wafers on the boat, the operation unit 33 inputs to the main control unit 32 the number of product wafers, the position of monitor wafers, and the like. The input wafer array conditions are input / output control unit 46
After the signal processing is performed by, the wafer arrangement parameter setting unit 51 via the processor 49 creates a wafer arrangement for performing transfer control, and this arrangement is stored in the storage unit 50. Also, the wafer arrangement parameter setting unit 51
Also checks whether the input wafer arrangement conditions are reasonable in performing the transfer operation.

Next, the operation unit 33 is instructed to start transferring the wafer.

When the transfer start instruction is given, the wafer detection sensor 15 is made to face the scheduled row of the cassette stocker 7, for example, the row I. Whether or not the wafer detection sensor 15 faces the column I is determined by a signal from the sensor 36. Lifting table 18
Is set to the lowest position, the lifting motor 20 is driven, and the lifting table 18 is lifted via the lifting screw 19.

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

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 reference position is detected by the wafer reference position sensor 16 for each cassette, and how many wafers are in each cassette. , Where the wafer is missing is detected.

Wafer detection and wafer number measurement are also performed for column II.
The horizontal movement of the cassette stocker 7 is
This is performed by operating the solenoid valve 31 via the driver 44 and driving the cylinder 17. Whether the cassette stocker 7 is in the position of the row II with respect to the wafer detection sensor 15
It 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 transferred to the moving operation parameter creating section through the input / output controller 46 and the processor 49.
Input to 52. In the movement operation parameter creating unit 52,
Based on the wafer arrangement parameter and the result of counting the number of wafers, if there is a shortage of product wafers, which cassette replenishment dummy wafer should be used for the shortage, or the wafer transfer order is determined, and transfer operation parameters are created. Then, the transfer operation parameter is input and stored in the storage unit 50.

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

The wafer transfer operation is performed via the transfer control execution unit 48. The transfer operation for one wafer and one wafer has been described above, and thus the description thereof will be omitted here. However, the transfer operation is performed based on the transfer operation sequence that is input to the storage unit 50 via the processor 49 in advance, and The transfer procedure with the arrangement determined by the wafer arrangement parameter is performed based on the transfer operation parameter.

The communication control unit 37 determines the signal output from the main control unit 32 and issues a command signal to the motor controller of the motor to be operated. Further, the main control unit 32 selects any one of the solenoid valves 30a, 30b, 30c, 30d, 30e when performing fractional processing of wafers (when transferring four or less wafers in this embodiment). The solenoid valves 30a, 30b, 30c, 30d, 30e are operated via the corresponding drivers 43a, 43b, 43c, 43d, 43e to suck the wafer onto the suction plate.

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

In addition, the result of counting the number of wafers, such as how many wafers are lacking in which cassette, the progress of transfer, etc. are displayed on the operation unit.

Although the number of wafers is automatically measured in the above embodiment, the number of wafers is counted by the operator and the operation unit 33
It goes without saying that the input may be made via.

[Effects of the Invention] As described above, according to the present invention, it is not necessary to manually replenish the insufficient wafers even if the product wafers supplied to the diffusion / CVD apparatus fluctuate, and the desired wafer arrangement is achieved. Since the wafers are transferred in such a manner that the wafer transfer efficiency can be greatly improved, and manual work during the process can be omitted, the process can be stabilized in the semiconductor manufacturing factory and the product quality can be stabilized. It has the excellent effects of promoting automation, automation, and eliminating dust in the factory.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a vertical diffusion device, FIG. 2 is an explanatory view of a wafer detection sensor, FIG. 3 is a block diagram showing an embodiment of the present invention, and FIG. 4 is an explanation of a main controller. 5 and 5 are explanatory views of wafer arrangement and wafer transfer. 2 is a wafer, 3 is a boat, 5 is a wafer transfer machine, 7 is a cassette stocker, 14 is a cassette, 15 is a wafer detection sensor, 32 is a main control unit, 49 is a processor, 51 is a wafer arrangement parameter setting unit, and 52 is The transfer operation parameter creation part is shown.

Claims (4)

[Claims] 1. A wafer transfer method of a transfer machine for transferring wafers loaded in a plurality of cassettes from the cassettes to a boat holding the wafers in multiple stages, wherein a wafer arrangement on the boat is set in advance. Therefore, the wafer transfer method is characterized in that the shortage of wafers on the boat is transferred while supplementing with dummy wafers. 2. A wafer transfer control device of a transfer machine for transferring wafers loaded in a plurality of cassettes from a cassette to a boat for holding wafers in multiple stages, and wafers other than dummy wafers are loaded. Wafer cassettes, dummy wafer cassettes loaded with dummy wafers for replenishment, an input unit for inputting the wafer loading state of each cassette, and transfer operation parameters are created based on the wafer loading states, and the transfer operation is performed. According to the operating parameters, if there is a shortage of wafers, a main controller that transfers the dummy wafers in the dummy wafer cassette to transfer the wafers while replenishing the shortage of the wafers on the boat. Wafer transfer control device. 3. The wafer transfer control device according to claim 2, further comprising a wafer detection sensor for detecting a wafer loading state of each cassette. 4. A semiconductor manufacturing apparatus equipped with a wafer transfer machine for transferring wafers loaded in a plurality of cassettes from the cassettes to a boat holding the wafers in multiple stages,
An input unit in which a controller of the wafer transfer machine inputs wafer cassettes in which wafers other than dummy wafers are loaded, dummy wafer cassettes in which dummy wafers for replenishment are loaded, and a wafer loading state of each cassette Then, a transfer operation parameter is created based on the wafer loading state, and if there is a shortage of wafers according to the transfer operation parameter, the dummy wafers in the dummy wafer cassette are transferred and the shortage of wafers on the boat And a main control unit for transferring wafers while replenishing the semiconductor manufacturing apparatus.