JPH0333066Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) This invention relates to an automatic wafer transfer device used in a semiconductor manufacturing process.

(Prior Art) When heat-treating wafers, the wafers in a carrier are transferred to a quartz boat, and an automatic wafer transfer machine is used for this transfer.

As is well known, this transfer machine uses a chuck to hold the wafer being pushed up inside the carrier.
After the wafers are transported to the transfer position on the quartz boat, the chuck is opened and the wafers are loaded into the wafer grooves of the quartz boat.Normally, only 25 wafers can fit in the carrier, so 100 wafers can be loaded into the carrier. Multiple transfer operations are required to fill the incoming quartz boat.

Conventionally, after transferring the wafers in the first carrier to a quartz boat, the operator inputs the number of wafers in the first carrier into a drive control device, and the device controls the transfer machine to the next transfer machine. It is moved to the transfer position and the next transfer is performed.

(Problem to be solved by the invention) When the conventional automatic wafer transfer machine transfers wafers to a quartz boat, the data on the number of wafers input to the control device is based on the assumption that there are no wafers at the transfer position. We are currently undergoing a transfer.

Therefore, if the operator makes a mistake in the number of wafers in the initial input of automation, for example inputting 24 instead of 25, the wafer will be placed on top of the last wafer, resulting in wafer damage. Therefore, it is conceivable to use a sensor to detect the wafer at the bottom of the wafer chuck. However, wafer transfer equipment has special circumstances, and simply providing a sensor will result in misjudgments and wafer stacking accidents.

In view of the above-mentioned circumstances, this invention aims to prevent wafers from being stacked on top of each other when transferring wafers in a carrier to a quartz boat.

[Structure of the idea]

(Means for Solving the Problems) This invention is an automatic wafer transfer device in which a wafer chuck that can be raised and lowered is provided on a slidable base. The optical axis of the sensor collides with the circumferential surface of the wafer boat, and the point of collision is between the most advanced wafer of the wafer boat and the wafer of the wafer boat within the distance between the facing surfaces of adjacent wafers in the wafer boat. This is an automatic wafer transfer apparatus characterized in that the sensor is located on the side and a transfer drive control means is connected to the sensor.

(Operation) After adjusting the position of the wafer detection sensor by the position adjustment mechanism, a plurality of wafers in the carrier are held between the wafer chucks, the chucks are moved along the quartz boat, and the wafer chucks are carried to the transfer position.

At this time, the wafer detection sensor is operating, but if there is a wafer in the quartz boat at the transfer position, the light from the light emitting section will be reflected by hitting the wafer, and the reflected light will enter the light receiving section. , actuates the drive control and stops the chuck from moving.

(Embodiment) An embodiment of this invention will be described with reference to the accompanying drawings, where the same reference numerals have the same names and functions.

A base 2 of the automatic wafer transfer machine 1 is provided with a wafer chuck 3 which can be opened and closed via an elevating mechanism, a ball screw B connected to a pulse motor 4, and an overlapping prevention device 5.

The overlapping prevention device 5 includes a wafer detection sensor 6 and a position adjustment mechanism 7 for adjusting the position of the sensor 6, as shown in FIG.

In this example, the wafer detection sensor 6 is a light emitting section 9.
It is a reflective sensor comprising a light receiving section 10 and a light receiving section 10, and is provided on the fixed plate 8.

Positioning of the sensor 6 is performed using a position adjustment mechanism 7.

The position adjustment mechanism 7 includes a vertical adjustment elongated hole 11 and a screw 12, a left and right adjustment feed screw 15, and a left and right fixing screw 16.

When the light emitting unit 9 is adjusted so that its optical axis L coincides with the center of the wafer 14 on the quartz boat, the position of the wafer 14 can be detected more accurately.

The sensor 6 is adjusted by the left-right feed screw 15 so that the distance t ₁ between the optical axis L of the light emitting unit 9 and the most advanced wafer 14a of the wafer chuck 3 is, for example, 3/32 inch (approximately 2.38 mm).

As shown in FIG. 3, the pitch interval t ₂ of the wafer grooves of the quartz boat 13 is 3/16 inches _. That is, at a position 3/32 inch apart, it is detected whether or not the wafer 14b is present in the wafer groove 20a, and the wafer 14b is transferred. Next, when this wafer 14 is transferred, the optical axis L of the sensor 6 is located between the wafer 14b and the wafer 14c, making it possible to prevent erroneous detection of the wafer 14 in the next wafer groove.

The light receiving section 10 of the sensor 6 is electrically connected to a drive control device C that controls the pulse motor 4.

Next, the operation of this embodiment will be explained.

When the operator inputs the number of carriers and wafers to be transferred using the keyboard K and starts the automatic transfer device, the pulse motor 4 is driven to rotate the ball screw B and the transfer device 1 is placed on the table 21. to the first carrier 22.

Therefore, when the 25 wafers in the first carrier 22 are pushed up by a push-up mechanism (not shown) and these wafers are clamped by the wafer chuck 3, the push-up mechanism is lowered and the pulse motor 4 rotates in the opposite direction to the above, and the transfer machine 1 is rotated. The wafer is moved to the transfer position W of the quartz boat 13 located at the bottom of the wafer chuck.

The transfer machine 1 is moved at high speed to shorten the time up to the vicinity of the transfer position, and after that, the transfer machine 1 is moved at low speed so as to be able to stop suddenly.

At this time, the light emitted from the light emitting part 9 of the sensor 6 is irradiated toward the transfer position W, but the wafer 1
4, the light travels straight and does not enter the light receiving section 10.

Therefore, the transfer position W of the lower part of the wafer chuck 3
It is confirmed that there is no wafer in the wafer, and the wafer is transferred according to the settings.

That is, the wafer chuck 3 is lowered and the wafer 1
After storing the wafers 4 in the wafer grooves 20 of the quartz boat 13, the wafers 14 are released and raised, and the wafer transfer machine 1 moves at high speed to the second carrier 23.

Next, if the operator operates the keyboard K and misidentifies the number of wafers that were 25 in the first carrier 22 and inputs, for example, 24, the pulse motor 4 will follow that instruction. The wafer transfer machine 1 is not moved to the transfer position, but the wafer 14 is placed in the wafer groove 20a to be transferred.
b, the light from the light emitting section 9 of the sensor 6 hits the circumferential surface of the wafer and is reflected, and the reflected light enters the light receiving section 10.

When reflected light enters the light receiving section 10, it is detected by the overlapping prevention device 5, and the detection signal drives the drive control device C to stop the pulse motor 4 and generate an alarm.

Next, the operator takes out the wafer 14b using tweezers or the like, and turns on the start switch (not shown).
When is pressed, the pulse motor 4 is driven again to move the transfer machine 1 to the next transfer position W, and the wafer transfer is performed in the same manner as before.

In this way, the wafers in the carrier are transferred to the quartz boat 13, and the wafers are accommodated in all the wafer grooves of the quartz boat 13.

This invention is not limited to the above-mentioned embodiment. For example, the wafer detection sensor of the overlapping prevention device 5 may be of a so-called transmission type in which a light emitting part and a light receiving part face each other on the same straight line instead of a reflective type. Of course, a type sensor may also be used.

[Effect of idea]

Since this invention is configured as described above, when a wafer exists at a predetermined wafer transfer position,
Since the wafer is detected by the wafer detection sensor and the predetermined wafer transfer operation is stopped, there is a remarkable effect that overlapping of wafers can be completely prevented. Further, the optical axis of the wafer detection sensor collides with the circumferential surface of the wafer in the wafer boat, and the point of collision is within the range of the distance between the most advanced wafer in the wafer chuck and the opposing surfaces of adjacent wafers in the wafer boat. Since the optical sensor for wafer detection is located on the wafer side of the wafer boat within the range of the distance between the most advanced wafer of the wafer chuck and the wafer facing surface, the wafer detection optical sensor After the wafer is detected and transferred, the optical axis does not collide with the peripheral surface of the rearmost wafer.

Therefore, it is possible to accurately detect whether or not there is a wafer at the position to be transferred, and there is no possibility of false detection after the wafer is transferred.

[Brief explanation of the drawing]

1 to 4 are views showing an embodiment of this invention, FIG. 1 is a perspective view thereof, FIG. 2 is an enlarged perspective view showing the overlapping prevention device of FIG. 1, and FIGS. 3 to 4 The figure shows the state of use. DESCRIPTION OF SYMBOLS 1... Transfer machine, 2... Base, 3... Wafer chuck, 5... Overlap prevention device, 6... Wafer detection sensor, 7... Position adjustment mechanism, W... Transfer position.

Claims (1)

[Scope of utility model registration request] In an automatic wafer transfer device that includes a wafer chuck that can be raised and lowered on a slidable base, an optical sensor for wafer detection is installed on the base, and the optical axis of the optical sensor is aligned with the circumferential surface of the wafer on the wafer boat. and the collision point is located on the wafer side of the wafer boat within the distance between the most advanced wafer of the wafer chuck and the opposing surfaces of adjacent wafers in the wafer boat, and the sensor An automatic wafer transfer device characterized in that a transfer drive control means is connected to the wafer transfer device.