JP2003109999A - Substrate treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breakage of a wafer and turn-over of boat and cassette in advance by stopping a substrate transfer device before such accident occurs in case when a substrate placement plate is brought into contact with the wafer, boat and cassette. SOLUTION: This substrate treatment device is provided with a substrate transfer device 1 that is provided with a substrate placement plate 11 to place a substrate 21, and it is also provided with an collision sensor 13 to detect any vibration during collision of the substrate transfer device.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing apparatus for producing a semiconductor device by forming a thin film on a substrate such as a semiconductor wafer or performing a process such as diffusion of impurities. More particularly, the present invention relates to a batch type substrate processing apparatus for processing a substrate by holding a predetermined number of substrates with a substrate holder. 2. Description of the Related Art In a batch type substrate processing apparatus having a vertical furnace as a reaction furnace for processing a substrate, semiconductor wafers, for example, silicon wafers are held in multiple stages in a horizontal posture on a boat as a substrate holder. The boat is charged into the reactor, a processing gas is introduced into the reactor, and the boat is further heated to perform required processing. [0003] Loading of unprocessed wafers in the state of being pulled out of the reactor and loading of processed wafers in the state of being pulled out of the reactor after substrate processing is performed by the substrate transfer machine. You. The substrate transfer machine is carried in from the outside of the substrate processing apparatus, and transfers a wafer between the cassette and the boat housed in the substrate processing apparatus. It has the function of rotating. [0004] The boat and the cassette are formed with grooves for supporting the peripheral edge of the wafer at a required pitch, and the substrate transfer machine loads and unloads wafers from and into the grooves of the boat and the cassette. Has become. That is, when loading a wafer into the boat or cassette, the wafer is placed on a substrate mounting plate,
The wafer is rotated to face the boat and the cassette, and the substrate mounting plate is inserted into the groove of the boat and the cassette. The wafer is slightly lowered, and the wafer is transferred to the groove of the boat and the cassette. When unloading wafers from the boat or cassette, insert the substrate mounting plate into the boat or cassette from a slightly lower position so as not to come into contact with the target wafer. The wafer is placed on the plate and retracted. [0006] The above-mentioned boat,
When an error occurs in the wafer holding position due to a manufacturing error of the cassette, or when the wafer is warped, the wafer may come into contact with the substrate mounting plate during the wafer transfer operation. In order to cause the substrate transfer device to perform a predetermined operation, there is a teaching operation in which the operator stores the position of the wafer in the apparatus. However, an error in the teaching operation causes the wafer and the substrate mounting plate to move between the wafer and the substrate mounting plate. Contact may also occur. In the case where the wafer and the substrate mounting plate are slightly in contact with each other, no problem occurs due to the contact as a result of the wafer being lifted. However, in some cases, the contact between the wafer and the substrate mounting plate may occur. As a result, it is conceivable that the wafer may be damaged, or the substrate transfer machine may defeat the boat or the cassette. If the wafer is damaged and the boat or cassette falls over, the substrate processing apparatus stops and the processing of the damaged wafer and the falling boat and cassette take a great amount of time. There was a problem that the operating rate was significantly reduced. The present invention has been made in view of such circumstances, and when a substrate mounting plate comes into contact with a wafer, a boat, or a cassette, the wafer is damaged or the substrate transfer machine is stopped before the boat or the cassette falls, Wafer damage accident, boat,
An object of the present invention is to prevent the cassette from falling over and improve the operation rate of the substrate processing apparatus. According to the present invention, there is provided a substrate processing apparatus provided with a substrate transfer machine having a substrate mounting plate on which a substrate is mounted. The present invention relates to a substrate processing apparatus provided with a collision sensor for detecting vibration. Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show a main part of the present embodiment, showing the relationship between a substrate transfer machine 1 and a boat 2, and including other devices, a reaction furnace, and a cassette constituting a substrate processing apparatus. The cassette shelves and the like to be stored are omitted. The substrate transfer machine 1 includes a housing 3 and the boat 2
The boat 2 is supported by a boat elevator (not shown) so as to be able to move up and down. A reaction furnace (not shown) is erected above the boat 2, and the boat 2 is inserted into and pulled out of the reaction furnace by raising and lowering the boat elevator. The substrate transfer machine 1 will be briefly described. A vertical guide 5 is provided upright on the bottom plate 4 of the housing 3, and an elevating stage 6 is rotatably provided on the vertical guide 5. The elevating stage 6 is provided at an upper end of the vertical guide 5. It can be moved up and down via a screw rod (not shown) rotated by the motor 7. The elevating stage 6 is provided with a rotatable stage 8 rotatably, and the rotatable stage 8 is provided with an advancing / retreating unit 9 capable of moving in a horizontal direction. The forward / backward unit 9 includes the substrate mounting plate 11 and the plate holder 1.
2 are supported. The advance / retreat unit 9 corresponds to the system configuration of the apparatus, and can support a required number of the substrate mounting plates 11.
When there are a plurality of sheets 1 (five sheets in the figure), the plate holders 12 can be individually raised and lowered, and the pitch of the substrate mounting plate 11 is variable. A collision sensor 13 is fixed to the uppermost plate holder 12. The collision sensor 13 emits a signal when a vibration of a predetermined value or more is detected, for example, when the substrate mounting plate 11 comes into contact with an obstacle. The boat 2 is mounted via a boat cap 15 on a lifting arm 14 extending horizontally from the boat elevator. In the boat 2, a top plate 17 is supported by three columns 18 extending upward from a bottom plate 16, and a wafer 21 is loaded into a groove formed in the column 18. The loading and unloading of the wafers 21 from and to the boat 2 are performed while the boat 2 is lowered. A boat tilt detector 22 is attached to a constituent member 23 of the housing 3 (for example, a frame of a clean unit) via a support 24. The boat tilt detector 22 is located at the same level as the top plate 17 of the boat 2 in a lowered state, and is further positioned on an extension of the substrate mounting operation direction of the substrate mounting plate 11. . The boat tilt detector 22 is connected to the boat 2
Is activated when it is tilted by a predetermined amount, and detects that the boat 2 has tilted when the substrate mounting plate 11 is tilted by contact with the wafer 21 or the boat 2. The boat tilt detector 22 will be described. The L-shaped slide member 25 is screwed by the support member 2 so that the vertical portion is on the boat 2 side.
Fixed to 4. The hole through which the screw 26 passes is elongated toward the center of the boat 2, and the position of the slide fitting 25 can be adjusted in the direction of approaching and separating from the boat 2. A contact plate 31 is attached to the boat 2 side of the vertical portion, and the side surface of the boat 2 of the plate 31 is an arc surface having the same radius as the top plate 17. A micro switch 27 is mounted on the slide fitting 25, and the micro switch 27 is operated by a displacement of an operation lever 28 in the direction of the center of the boat 2. A pin 29 is provided slidably in the radial direction of the boat 2 through the vertical portion of the slide fitting 25 and the backing plate 31, and the pin 29 is directed toward the center of the boat 2 by a spring (not shown) or the like. One end of the pin 29 is provided at a predetermined position of the boat 2, in FIG. 3, with a slight gap, for example, 2 mm, from the upper end of the support column 18. Lever 28
Is in contact with The boat 2 tilts and the top plate 17
When the pin abuts against the backing plate 31, the pin 29 is pushed and displaced by the top plate 17, and the displacement of the pin 29 causes the operation lever 28 to rotate and the micro switch 27 to operate. . Since the abutment plate 31 abuts on the top plate 17 with the same curvature, no impact force acts locally. Also, since the boat 2 is hot when pulled out of the reaction furnace,
As the material of (1), it is preferable to use a heat-resistant synthetic resin such as a fluorinated resin having a buffering action. Also, the slide fitting 25
Into a box shape to accommodate the microswitch 27,
By selecting a material having a high heat insulating property, the material can also function as a heat shielding member. The collision sensor 13 may be of any type as long as it can be attached to the plate holder 12. In this embodiment, the collision sensor 13 is a thin type.
An axial acceleration sensor integrated on a single IC chip is used. That is, a differential capacitor circuit is formed on a silicon wafer, and the polysilicon layer of the silicon wafer functions as a spring. Based on the waveform and phase output from the differential capacitor circuit when a vibration is applied, It detects the magnitude and direction of vibration (acceleration). Next, when driving the substrate transfer machine 1,
Vibration is generated by rotation of a motor that is a driving source of the substrate transfer machine 1. Therefore, the vibration generated when the substrate transfer machine 1 is operating normally and the substrate mounting plate 1
It is necessary to identify the vibration generated when the boat 1 collides with the boat 2 and the wafer 21. As an identification method, a vibration cycle when the substrate transfer machine 1 operates normally and a vibration cycle generated by collision differ from each other, and thus the method is determined based on the vibration cycle (frequency). Further, the amplitude (magnitude) of the vibration when the substrate transfer device 1 operates normally and the amplitude (magnitude) of the vibration when the substrate transfer machine 1 collides are naturally different, and there is a method of identifying the amplitude based on the amplitude. . In the present embodiment, in order to improve the accuracy and reliability, the vibration period and the amplitude are identified. That is, the threshold of the vibration frequency and the threshold of the amplitude are set. The vibration frequency during the operation of the substrate transfer machine 1 is based on the rotation of the motor, and is relatively low at 150 Hz.
３００300 Hz, the vibration frequency at the time of collision is based on the elastic vibration of the constituent members,
Reaches 900Hz. Therefore, the vibration frequency threshold is 300
Hz to 700 Hz. The magnitude of the vibration generated when the substrate transfer machine 1 operates is 0.2 G
And the magnitude of vibration generated at the time of collision is 0.7 G
That is all. Therefore, the threshold value of the magnitude of the vibration is 0.2 G to
Set between 0.7G. When the vibration detected by the collision sensor 13 exceeds the threshold value in both the vibration frequency and the magnitude of the vibration,
The signal of "collision" is output. In order to facilitate signal processing, the collision sensor 13 itself performs signal processing, and a signal output from the collision sensor 13 is a binary signal indicating the presence or absence of a collision. FIG. 4 schematically shows a control system according to this embodiment. In the figure, reference numeral 33 denotes a main controller of the substrate processing apparatus.
Reference numeral 34 denotes a drive control unit for controlling the drive of the substrate transfer machine 1;
5 is a monitor. The drive controller 34 operates the substrate transfer machine 1 based on a command from the main controller 33 to transfer the wafer 21. The collision sensor 1
3, when a collision occurs, a collision signal is issued to the drive control unit 34 based on the detected vibration. The boat tilt detector 22 outputs a boat tilt signal to the drive control unit 34 when the boat 2 tilts and the micro switch 27 operates. The operation will be described below. A wafer 21 is received on the substrate mounting plate 11 from a wafer cassette (not shown), and the substrate mounting plate 11 is moved up and down, the rotary stage 8 is rotated, and the advance / retreat unit 9 is moved forward / backward. The wafer 21 on the mounting plate 11 is transferred to the boat 2. When a predetermined number of wafers 21 are loaded into the boat 2, the boat 2 is loaded into a reaction furnace (not shown) by a boat elevator (not shown), and required processing is performed. After the processing, the boat 2 is pulled out, and the processed wafers 21 are discharged to the wafer cassette by the substrate transfer machine 1. In the transfer operation of the wafer 21 by the substrate transfer machine 1, when the substrate mounting plate 11 collides with the boat 2 or collides with the wafer 21 loaded in the boat 2, the collision sensor 13 detects vibration at the time of collision and sends a signal to the drive control unit 34. The boat tilt detector 22 operates when the boat 2 tilts due to a collision, and sends a signal to the drive control unit 34. When a signal is input from at least one of the collision sensor 13 and the boat tilt detector 22, the drive control unit 34 immediately stops the substrate transfer machine 1, and damages the wafer 21 and falls the boat 2. To prevent. Further, the collision, the inclination of the boat 2, and the stop of the substrate transfer machine 1 are input to the main controller 33. The main controller 33 displays the information on the monitor 35 to inform the operator of the situation. It is needless to say that the boat tilt detector 22 detects not only the collision but also the tilt even if the boat is not correctly positioned and tilted. Further, the collision sensor 13 may be provided on each of the substrate mounting plates 11. Further, the position where the collision sensor 13 is provided is not limited to the plate holder 12, but may be any position where vibration at the time of collision can be detected. As described above, according to the present invention, in a substrate processing apparatus provided with a substrate transfer machine having a substrate mounting plate for mounting a substrate, the substrate processing machine collides with the substrate transfer machine. A collision sensor that detects vibrations at the time is provided, so that the substrate transfer machine can be stopped immediately upon contact, and the excellent effect of preventing the boat from falling down and damaging the wafer is exhibited. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation view showing a main part of an embodiment of the present invention. FIG. 2 is a view taken in the direction of arrow A in FIG. 1; FIG. 3 is a view taken in the direction of arrow B in FIG. 1; FIG. 4 is a schematic control block diagram of the embodiment of the present invention. [Description of Signs] 1 Substrate transfer machine 2 Boat 11 Substrate mounting plate 12 Plate holder 13 Collision sensor 21 Wafer 22 Boat tilt detector 27 Micro switch 31 Backing plate

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Claims (1)

Claims: 1. In a substrate processing apparatus including a substrate transfer device having a substrate mounting plate on which a substrate is mounted, a collision detecting a vibration at the time of collision with the substrate transfer device. A substrate processing apparatus provided with a sensor.