JPH01144647A - Counter for semiconductor wafer - Google Patents

Abstract

PURPOSE:To perform reliable operation of wafer detection by mounting one element for a transmission type photoelectric sensor to a hand fitting section for a robot and the other element to the rear of a carrier and installing the element to a vertical movable type sensor holder detachably bonded with a vertical moving module for the robot through a connecting mechanism. CONSTITUTION:A light-emitting element 41 for a transmission type photoelectric sensor composed of a pair of mutually opposed light-emitting element 41 and photo-detector 42 is set up to a module 33, to which a hand 34 on the robot 3 side is mounted, and the photo-detector 42 to a vertically movable type sensor holder 7 disposed on the rear side of a carrier 2. The sensor holder 7 is connected detachably to a hook 35 fitted to an elevating turning module 32 on the robot 3 side through a connecting mechanism 8. The connecting mechanism 8 is composed of a connecting rod 81, a nose of which is engaged mutually with the hook 35 set up to the module 32 for the robot 3, a guide rod 82 guide- supporting the rod 81 in the before and behind direction to the sensor holder 7, and a driving cylinder 83 being loaded on the sensor holder 7 and forwarding and retreating the connecting rod 81.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a wafer processing device or wafer inspection device that performs various processes such as film formation and etching on semiconductor wafers, and a loading device that stores a plurality of wafers. The present invention relates to a semiconductor wafer counting device that is installed on a wafer transfer robot that receives and transfers wafers to and from an unloading carrier to detect the number of wafers stored in the carrier and their storage positions.

[Conventional technology]

First, the general configuration of the above-mentioned wafer transfer robot and a conventional wafer counting device equipped on the wafer transfer robot will be explained with reference to FIGS. 2 and 3.

In the figure, 1 is a semiconductor wafer, 2 is a plurality of wafers 1
3 is carrier 2 and the next stage wafer processing equipment.

This is a wafer transfer robot that receives and transfers wafers 1 to and from a wafer inspection device. This robot 3 includes a drive unit 31 and a drive shaft of the drive unit 31 connected to the vertical direction (
Z), the vertical and turning movement module 32 that is operated in the turning direction (θ), and the movement in the front and back direction (
It consists of an assembly of a linear movement module 33 that is operated to move in the direction X) and a wafer holding hand 34 as a vacuum suction chuck coupled to the module 33.

The handling operation of the wafer 1 by the wafer transfer robot 3 is well known, and the handling operation of the wafer 1 by the wafer transfer robot 3 is known.
Place it in the designated position facing robot 3,
In this state, the hand 34 is first rotated 180 degrees from the state shown in the figure, and the hand 34 is directed toward the carrier 2, where the robot 3
The hand 34 is operated up and down 5 front and back directions to take out one wafer 1 housed in the carrier 2, and then the hand 34 is rotated 1 back and forth to operate the wafer processing apparatus (not shown). Otherwise, the receiver is passed to a wafer inspection device.

Further, when the wafer 1 is to be collected by the carrier 2, the operation is reversed to that described above.

On the other hand, the wafer 1 is transferred from the carrier 2 by the operation of the robot 3.
When loading and unloading wafers, it is important to check the number of wafers stored in the carrier 2 and detect the storage position for wafer process control and operation control of the robot 3. As a means, the robot 3 is equipped with the following wafer counting device. As such a wafer counting device, in FIG. 2, a module 33 to which a hand 34 is attached is equipped with a reflective optical sensor 4 on the side opposite to the hand 34. With this configuration, the robot 3 is moved in the vertical direction (
By moving up and down to Z), the number of wafers stored in the carrier and the storage position thereof can be detected from the scanning signal of the photoelectric sensor 4. In the figure, reference numeral 5 indicates a control section for the photoelectric sensor 4, and reference numeral 6 indicates an operation control section for the robot 3.

Furthermore, in the example shown in FIG. 3, a transmissive optical sensor that combines a light emitting element and a light receiving element is used instead of a reflective optical sensor, and the module 33 of the robot 3 has one light emitting element 41. A plurality of light receiving elements 42 corresponding to each storage stage position of the wafer 1 are attached to a columnar sensor holder 7, which are arranged on the rear side of the carrier 2 and facing the light emitting elements 41. Here, by lifting and lowering the light emitting element 41 by robot operation, the number of stored wafers 1 and the storage position thereof are detected from the scanning signal of the light receiving element 42.

[Problem that the invention seeks to solve]

However, each of the conventional counting methods described above has the following problems. That is, in the method shown in FIG. 2, if there is variation in the distance l between the reflective optical sensor 4 installed on the robot 3 side and the end surface of the wafer 1 stored in the carrier 2, detection errors may occur. Furthermore, depending on the film components deposited on the wafer 1, it may be difficult to detect with a reflective optical sensor, resulting in low reliability. On the other hand, the method using the transmission type optical sensor shown in Fig. 3 can prevent the occurrence of detection errors caused by the reflection type optical sensor shown in Fig. 2; 42, which increases the cost in terms of equipment, and if the pitch of the wafer storage stages in the carrier 2 is very narrow, the light emitted from the light emitting element 41 will be diffused, causing the wafers to be adjacent to each other. There is a risk that mutual interference will occur between matching light receiving elements 42 and a counting error will occur.

The present invention has been made in view of the above points, and an object of the present invention is to provide a semiconductor wafer counting device which is low in cost and is capable of reliable wafer detection operation.

[Means for solving problems]

In order to solve the above problems, according to the present invention, one element of a transmission type optical sensor consisting of a pair of opposing light emitting elements and a light receiving element is mounted on the hand attachment part of the robot, and the other element is mounted on a carrier. The sensor holder is attached to a vertically movable sensor holder placed between and behind the sensor holder, and the sensor holder is detachably connected to the vertically movable module of the robot via a connecting mechanism.

[Operation] When counting the wafers stored in the carrier with the above configuration, the coupling mechanism is coupled to the robot side. Therefore, when the robot moves up and down, the sensor holder moves in conjunction with the up and down movement of the robot's hand attachment part, and the light emitting element of the opposed transmission type photoelectric sensor and the light receiving element equipped on the sensor holder remain facing each other with the carrier in between. It moves synchronously in the vertical direction to optically read and scan the inside of the carrier. This makes it possible to reliably detect the number of wafers stored in the carrier and their storage positions from the scanning signal of the light-receiving element without fear of detection errors. Furthermore, only one light-receiving element is required, and the structure can be constructed at low cost. When the robot performs a wafer handling operation based on the data obtained in the wafer counting operation, the connecting mechanism is operated backward to separate the sensor holder and the robot. This allows the robot to be operated without interference with the sensor holder.

〔Example〕

FIG. 1 shows an embodiment of the present invention, and the same members corresponding to FIGS. 2 and 3 are given the same reference numerals. That is, according to the present invention, the light emitting element 41 of a transmission type optical sensor consisting of a pair of light emitting elements 41 and light receiving elements 42 facing each other is attached to the module 33 equipped with the hand 34 on the robot throat 3 side. Opposing light receiving element 42
is attached to a vertically movable sensor holder 7 provided on the back side of the carrier 2, and the sensor holder 7 is connected via a connecting mechanism 8 to a hook 35 provided on a lifting/swinging module 32 on the robot 3 side. They are removably connected.

Here, the sensor holder 7 is formed as an L-shaped frame, and its base is guided and supported by a guide rod 91 pulled out below from a base 9 on which the carrier 2 is mounted. On the other hand, the connecting mechanism 8 includes a connecting rod 81 whose tip engages with the hook 35 provided on the module 32 of the robot 3, and a guide rod that guides and supports the connecting rod 81 in the front-rear direction with respect to the sensor holder 7. 82, and a drive cylinder 83 which is mounted on the sensor holder 7 and moves the connecting rod 81 forward and backward in the direction of arrow P between the solid line and dotted line positions.

Next, the wafer counting operation with the above configuration will be explained.

First, the connecting rod 81 is advanced to the solid line position shown in the figure, and its tip is engaged with the hook 35 on the robot 3 side. In this state, the robot 3 is raised and lowered by commands from the operation control section, so that the sensor holder 7 Follows the vertical movement of 3,
The light emitting element 41 and the light receiving element 42 move up and down while maintaining their relative positions facing each other. By activating the photoelectric sensor, the inside of the carrier 2 can be optically read and scanned to detect the number of wafers 1 stored and the storage position thereof. Moreover, in the above configuration, the raising and lowering operation of the sensor holder 7 is linked to the vertical movement of the robot 3, so there is no need for an independent drive source for the sensor holder 7, and the light emitting element 41 and the light receiving element 42 are maintained in opposing positions. You can scan by moving synchronously while holding the camera.

Further, when proceeding to a wafer handling operation after wafer counting, the connecting rod 81 is retracted to the dotted line position by the drive cylinder 83 of the connecting mechanism 8 to release the engagement with the hook 35 on the robot 3 side.

Thereby, the robot 3 can be operated without interference with the sensor holder 7.

Note that in the illustrated example, the light emitting element 41 is installed on the robot 3 side and the light receiving element 42 is installed on the sensor holder 7, but conversely, the light emitting element 41 is installed on the sensor holder 7, and the light receiving element 42 is installed on the robot 3 side. It is also possible to implement it by

〔Effect of the invention〕

As described above, according to the present invention, one element of a transmission type optical sensor consisting of a pair of light emitting elements and light receiving elements facing each other is mounted on the hand attachment part of the robot, and the other element is mounted on the hand mounting part of the robot with a carrier in between. It is attached to a vertically movable sensor holder placed behind the robot, and the sensor holder is removably connected to the robot's vertically movable module via a coupling mechanism, making it simple and compact. It is possible to reliably detect the number of wafers stored in the wafer and the storage position without any detection errors, and the reliability of the detection can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIGS. 2 and 3 are block diagrams of conventional semiconductor wafer counting devices. In each figure, semiconductor wafer, 2: carrier, 3: wafer transfer robot, 31: drive unit, 32: vertical, rotation movement module,
33: linear movement module, 34: hand, 41: light emitting element of transmission type optical sensor, 42: light receiving element, 7: sensor holder, 8: connection mechanism. Figure 2 Figure 1 Figure 3

Claims (1)

[Claims] A semiconductor device that is installed on a wafer transfer robot that takes wafers in and out of a carrier with open front and rear surfaces that stores multiple semiconductor wafers in a stacked manner, and detects the number of wafers stored in the carrier and their storage position. The wafer counting device is a transmission type photoelectric sensor consisting of a pair of light emitting elements and light receiving elements facing each other, and one element of the transmission type photoelectric sensor is placed in the hand attachment part of the robot, and the other element is placed behind it with a carrier in between. A semiconductor wafer counting device, characterized in that it is attached to a vertically movable sensor holder, and the sensor holder is detachably connected to a vertically movable module of a robot via a coupling mechanism.