JPH03154361A - Transfer apparatus for semiconductor wafer - Google Patents

Abstract

PURPOSE:To prevent the damage of a semiconductor wafer by stopping a motor when the currents of the motor exceed the specified value above normal load currents after the lapse of a specified time after the point of time when the motor has operated. CONSTITUTION:This is provided with current detectors 29-32, which detect the currents of DC motors 3, 9 and 18, alarm devices 38-41, and motor control means 34-37, which are connected to said current detectors 29-32. And the motor control means 34-37 respectively stop the DC motors 3, 9, 15 and 18 when the currents of the DC motors 3, 9, 15 and 18 have exceeded the values 1.2 times the normal load current average values after the lapse of, for example, 0.1 second from the points of time when the DC motors 3, 9, 15 and 18 were operated, and also issue alarms from alarm devices 38-41. Accordingly, it prevents the stress above the specified value from occurring in the semiconductor wafer. Hereby, it can prevent the semiconductor wafer from being damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a semiconductor wafer transfer device such as a semiconductor wafer transfer device or a semiconductor wafer transfer device.

(Prior art 1) Conventionally, a semiconductor wafer transfer device (Japanese Unexamined Patent Application Publication No. 1983-1999) is used to automatically transfer semiconductor wafers between wafer storage containers.
131465).

FIG. 2 is a schematic front sectional view showing a conventional semiconductor wafer transfer device, and FIG. 3 is a schematic plan view showing a part of the semiconductor wafer transfer device shown in FIG. In the figure, l is a table, 2 is a rod attached to table 1, and rod 2
is supported so that it can move up and down. 3 is a DC motor with a speed reducer; 4 is a conversion mechanism for converting the rotational movement of the DC motor 3 into vertical movement of the rod 2; and 1a is provided on the table l. Reference numeral 6 denotes a Teflon cassette positioned by the positioning tool 5, and the Teflon cassette 6 has a storage groove for storing 25 semiconductor wafers. 7 is a pusher located in the hole la, and the pusher 7 is made of Teflon. 8 is a rod attached to the pusher 7, and the rod 8 is supported so as to be movable up and down. 9 is a DC motor with a reducer, 10
1 is a conversion mechanism that converts the rotational motion of the DC motor 9 into the vertical motion of the rod 8; 11 is a positioning tool attached to the hole tb of the table L; the positioning tool 11 is made of Teflon. A quartz boat 12 is positioned by the positioning tool 11, and the quartz boat 12 has a storage groove for storing 25 semiconductor wafers. Reference numeral 13 denotes a pusher located in the hole lb, and the pusher 13 is made of Teflon. 14 is a rod attached to the pusher 13, and the rod 14 is supported so as to be movable up and down. 15 is a DC motor with a speed reducer, 16 is a conversion mechanism that converts the rotational movement of the DC motor 15 into vertical movement of the rod 14, and 17 is a moving device (not shown) provided so as to be movable in the horizontal direction of the drawing sheet. ), 18 is a DC motor with a speed reducer attached to the moving device, 19 is a pulley attached to the output shaft of the DC motor 18, 20 is a pulley attached to the shaft 17, 21 is a belt hung on pulley 19.20,
Reference numerals 22 and 23 denote female threaded portions provided on the shaft 17, and the winding directions of the threads of the male threaded portions 22 and 23 are opposite to each other.

Reference numerals 24 and 25 indicate sliding nuts screwed into the female threaded portions 22 and 23, respectively, and the sliding nuts 24 and 25 are guided by a moving device so as to be movable in the left and right directions in the plane of the drawing. 26.27
are holders attached to sliding nuts 24 and 25, respectively; holders 26 and 27 are made of Teflon;
6.27 has a holding groove for holding 25 semiconductor wafers.

A holding device 33 is composed of the shaft 17, the DC motor 18, the holders 26, 27, and the like. Reference numeral 28 denotes a semiconductor wafer, and in the illustrated state, the semiconductor wafer 28 is housed in a Teflon cassette 6.

A case will be described in which the semiconductor wafer 28 is transferred from the Teflon cassette 6 to the quartz boat 12 using this semiconductor wafer transfer device. First, from the state shown in FIG. 2, the semiconductor wafer 28 is raised by the pusher 7 by operating the DC motor 9, and then the holder 26, 27 is closed by operating the DC motor 18. As shown in the figure, the semiconductor wafer 28 is held by the holders 26 and 27. Next, after the pusher 7 is lowered, the holding device 33 is moved to the right in FIG. 4 by the moving device, and the semiconductor wafer 28 is positioned above the quartz boat 12 as shown in FIG. Next, by operating the DC motor 3, the table l is raised, and by operating the DC motor 15, the pusher 13 is raised, and as shown in FIG.
3, the semiconductor wafer 28 is supported. next,
By operating the DC motor 18, the holder 26.2
After opening 7, when the pusher 13 is lowered by operating the DC motor 15, as shown in FIG.
The semiconductor wafer 28 is now housed in the quartz boat 12. After that, by operating the DC motor 3,
After the table 1 is lowered, the holding device 33 is moved to the left in FIG. 7 by the moving device, and the state returns to the state shown in FIG. 2.

Furthermore, when transferring the semiconductor wafer 28 from the quartz boat 12 to the Teflon cassette 6 using this semiconductor wafer transfer device, the operation described above may be reversed.

[Problems to be Solved by the Invention] By the way, if the Teflon cassette 6 is contaminated, the semiconductor wafer 28 will be contaminated, so the Teflon cassette 6 is frequently cleaned with a chemical solution.
is deformed. Further, since the quartz boat 12 is inserted into a heating furnace such as a CVD device, the quartz boat 12 is deformed, and when the quartz boat 12 is cleaned with a chemical solution, the quartz boat 12 is eroded by the chemical solution. Therefore, the Teflon cassette 6 and quartz boat 12 are stored in one storage groove! q2 semiconductor wafers 28 enter or the semiconductor wafer 2
In some cases, the semiconductor wafer 28 may not be properly stored in the Teflon cassette 6 or the quartz boat 12, such as when the semiconductor wafer 8 is stored diagonally in the storage groove of the Teflon cassette 6 or the quartz boat 12. There may be cases where the position of the storage groove and the position of the holding groove of the holder 26, 27 do not match. If the semiconductor wafer 28 is not properly stored in the Teflon cassette 6 or the quartz boat 12 and the pusher 7.13 lifts the semiconductor wafer 28, a large stress will be generated on the semiconductor wafer 28, causing damage to the semiconductor wafer 28. There is.

Moreover, when the semiconductor wafer 28 is lifted by the pusher 7.13 in a state where the positions of the storage grooves of the Teflon cassette 6 and the quartz boat 12 and the positions of the holding grooves of the holder 26.27 do not match, the semiconductor wafer 28 The top of is holder 2
6.27, a large stress is generated in the semiconductor wafer 28, and the semiconductor wafer 28 may be damaged. Further, when the semiconductor wafer 28 is raised by the pusher 7.13, two semiconductor wafers 28 may enter into one holding groove of the holder 26.27. If the holders 26, 27 are closed in such a state, a large stress may be generated on the semiconductor wafer 28, and the semiconductor wafer 28 may be damaged. Also, quartz boat 1
The semiconductor wafer 28 stored in the Teflon cassette 6
Even when the table 1 is raised in order to transfer the semiconductor wafer 28 to the holder 26, the upper part of the semiconductor wafer 28 enters the holding groove of the holder 26, 27 as shown in FIG. .27, a large stress is generated in the semiconductor wafer 28, and the semiconductor wafer 28 may be damaged.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a semiconductor wafer transfer device that can prevent semiconductor wafers from being damaged.

Means for Solving 1 Problem] In order to achieve this object, the present invention provides a semiconductor wafer transfer device in which a motor drives at least one of a pusher, a holder, and a table, and a current detection method that detects the current of the motor. and a motor control means for stopping the motor when the current of the motor exceeds a predetermined value which is equal to or higher than the normal load current after a predetermined period of time has passed since the motor was started.

This semiconductor wafer transfer apparatus can prevent stress exceeding a predetermined value from being generated in the semiconductor wafer.

[Embodiment] FIG. 1 is a block diagram showing a part of a semiconductor wafer transfer apparatus according to the present invention. In the figure, 29-32 are current detectors that detect the current of DC motors 3,9,15,18, 38-41 are alarm devices, and 34-37 are motor controls connected to current detectors 29-32, respectively. The motor control means 34 to 37 each have a direct current motor 3.
When the current of the DC motor 3.9.15.18 exceeds 1.2 times its normal load current average value after 0.1 seconds from the time when the DC motor 3.9.15.18 is activated, the DC motor 3.9. 9
．． 15.18 and alarm devices 38 to 4.
The alarm will be issued from 1.

By the way, in the case of normal normal load, the DC motor 3.
When the current of 3.9.15.18 fluctuates within a range of ±15% of the current average value, that is, within the range of normal load current, and stress that may damage the semiconductor wafer 28 occurs, the DC motor 3.9.15. The current of DC motor 3.9.15.18 is more than 1.3 times the average normal load current, but in this semiconductor wafer transfer device, the current of DC motor 3.9.15.18 is 1.2 times the average normal load current. Since the motor control means 34 to 37 stop the DC motors 3.9 and I5.18 when the stress exceeds the predetermined value, it is possible to prevent stress exceeding a predetermined value from being generated on the semiconductor wafer 28. 28 will not be damaged.

Also, when starting the DC motor 3.9.15.18, a current that is 1.5 to 2 times the average normal load current is generated.
In this semiconductor wafer transfer device, a DC motor 3.
Even if the current of DC motor 3.9.15.18 exceeds 1.2 times the normal load current average value, the DC motor 3.
9.15.18 Because it does not stop, DC motor 3.9
．． Direct current motor 3.9, I5.1 immediately after starting 15.18
8 never stops. Furthermore, motor control means 34
~37, respectively, when the current of the DC motor 3.9.15.18 exceeds 1.2 times the normal load current average value,
Since the alarm devices 38 to 41 issue an alarm, it can be known that the DC motor 3.9.15.18 has stopped.

In the above-described embodiments, the case where the semiconductor wafer transfer device is a semiconductor wafer transfer device has been described, but the present invention can also be applied to a case where the semiconductor wafer transfer device is a semiconductor wafer transfer device or the like. Further, in the above embodiment, the delay time was set to 0.1 seconds, but the delay time may be set depending on the type of motor, etc. Furthermore, in the above embodiment, the current for stopping the DC motor 3.9.15.18, that is, the set current value of the motor control means 34 to 37, was set to 1.2 times the average current value, but the DC motor 3.91 Even if the current of .15.18 is five times the average current value, the semiconductor wafer 28 may not be damaged.
The set current value of the motor control means 34 to 37 may be up to five times the average current value.

Furthermore, when a single motor performs a plurality of operations, the normal load current may change depending on the operation, so the set current value of the motor control means may be determined for each operation.

Furthermore, in the above embodiment, a DC motor 3.9.15.18 was used as the motor, but an AC motor or any other type of motor may be used as long as it is a type of motor that can detect changes in load current.

〔Effect of the invention〕

As explained above, in the semiconductor wafer transfer device according to the present invention, it is possible to prevent stress exceeding a predetermined value from being generated in the semiconductor wafer, and therefore it is possible to prevent the semiconductor wafer from being damaged. As described above, the effects of this invention are remarkable.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a part of a semiconductor wafer transfer device according to the present invention, FIG. 2 is a schematic front sectional view showing a conventional semiconductor wafer transfer device, and FIG. 3 is a block diagram showing a part of a semiconductor wafer transfer device according to the present invention. A schematic plan view showing a part of the transfer device, and FIGS. 4 to 7 are explanatory views of the operation of the semiconductor wafer transfer device shown in FIGS. 2 and 3. l...Table 3...DC motor 7...Pusher 9...DC motor 3...Pusher 5...DC motor 8...DC motor 6.27...Holder 9-32. ...Current detectors 4 to 37...Motor control means 3.9.15.18...DC motors 29 to 32...Current detectors 34 to 37...Motor control means 4

Claims (1)

[Claims] 1. A semiconductor wafer transfer device in which a motor drives at least one of a pusher, a holder, and a table, including a current detector that detects the current of the motor, and a current detector that detects the current of the motor after a predetermined period of time from the time when the motor is activated. A semiconductor wafer transfer apparatus comprising: motor control means for stopping the motor when the current exceeds a predetermined value that is equal to or higher than a normal load current.