JPH01230245A - Transfer apparatus - Google Patents

Abstract

PURPOSE:To avoid breakdown and abrasion of disks, by monitoring a load applied on holders when a plurality of the disks which are aligned and contained in a first container at a predetermined interval are held with a pair of holders with the aligned state maintained and transferred into a second container. CONSTITUTION:Wafers 1 are transferred between a first transfer container, i.e., a wafer cassette 2, in which a plurality of semiconductor wafers 1 are contained and a second container for treatment, i.e., a quartz boat 3 for heat treatment. At this time, one group of the groups of a plurality of the aligned wafers is held with facing holder 10a and 10b that can be slid in the up and down directions and transferred. Coil springs 14 having desired spring forces are provided in supporting tools 13a and 13b which support the holder 10a and 10b. Extending force is generated in each spring 14 by the friction load that is yielded between the wafer 1 and a pushing part 8 which pushes up the wafer. The extension is detected with a sensor 15 that is provided at the upper end part of the holder 10a. When the excessive load is applied on the wafer 1, the operation is stopped.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a transfer device.

(Conventional technology) Semiconductor manufacturing processes such as oxidation process and diffusion process.

As a means to perform CVD process, annealing process, etc.

Mainly used in heat treatment equipment. That is, 150 semiconductor wafers are arranged in a heat treatment reactor, a heat-resistant support such as a quartz boat is carried in, and the wafers are heat-treated. All of these steps are automatically executed, so when performing this heat treatment, there are operations such as transferring the wafer to be processed, which has been stored in a wafer cassette and transported from the previous process, to the quartz boat for heat treatment, and the operation after the heat treatment. A transfer device is used to transfer the wafers from the quartz boat to the wafer cassette.

This transfer device consists of a wafer holder, in which a plurality of grooves at a predetermined pitch are provided at equal intervals on the opposing surfaces of a pair of clamping plates arranged opposite each other, and It is comprised of a clamping/extracting drive unit that moves relatively in the direction, and a robot mechanism that moves the holding unit in the x, y, and z directions.

This transfer device performs a transfer operation between the wafer cassette and the quartz boat. In this transfer operation, for example, when transferring wafers from a wafer cassette to a quartz boat, the multiple wafers stored in the wafer cassette are first lifted to a predetermined height from within the wafer cassette by a push-up mechanism. and then relatively move the holding plate in the opposite direction by the holding/extracting drive unit so that the periphery of the wafer is engaged with the plurality of raised wafer holding grooves provided in the holding unit. and sandwich the plurality of wafers. This clamped wafer is transported onto the quartz boat by the moving section and mounted at a desired position on the quartz boat. The transfer operation is performed in this manner.

This transfer device is disclosed in Japanese Patent Application Laid-open No. 54-34774, Japanese Patent Application Publication No. 62-69633, Japanese Patent Application Publication No. 61-224430, Japanese Patent Publication No. 61-4186, Japanese Utility Model Publication No. 61-97842, Japanese Utility Model Application Publication No. 61-9784, It is well known from No. 33443 and Japanese Utility Model Application Publication No. 61-27640.

(Problem to be Solved by the Invention) However, in the above conventional technology, when inserting or removing a wafer into a wafer cassette or a quartz boat, the predetermined By aligning the plurality of grooves with a predetermined pitch with the plurality of grooves with a predetermined pitch provided at the wafer setting position of the wafer cassette or quartz boat, the wafer is naturally placed between the holding part and the wafer cassette, or between the holding part and the quartz boat. However, if the grooves of the holding part and the wafer cassette, or the holding part and the quartz boat do not match each other due to a slight timing difference, or the wafer is moved from the groove to the quartz boat. If there is any obstacle during the transfer, the wafer cannot be transferred smoothly, and the wafer surface may come into contact with the edge of the groove and move while rubbing, or if the wafer is badly misaligned, the wafer may not be transferred smoothly. There was a problem that the transfer operation could not be performed or in the worst case, the wafer could be damaged. Further, even when the wafer is moved while rubbing as described above, there is a problem in that the stress generated at that time damages the element pattern on the wafer surface and causes defects.

Furthermore, the damage and friction of the wafer generates dust, and the influence of this dust lowers the yield.

The present invention has been made in response to the above-mentioned problems, and aims to provide a highly reliable transfer device by preventing damage and friction of the plate-shaped object.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a means for holding a plurality of plate-shaped objects arranged and stored in a first storage container at predetermined intervals, by moving a pair of gripping pieces facing each other in opposite directions. In a device that grips a supported plate-like object while maintaining an aligned state by moving and transfers it to a second storage container, a load applied to the plate-like object or the gripping piece during the transfer operation process of the plate-like object. The purpose of the present invention is to obtain a transfer device characterized in that it is equipped with means for monitoring.

(Effect) By providing a means for monitoring the load applied to the plate-like object or the gripping piece, if a relative positional shift occurs between the plate-like object row and the gripping piece, the load on the plate-like object or the gripping piece will be lower than necessary. It is possible to immediately detect when a load is applied, and to prevent damage to the plate-like object or the objects that come into contact with it, as well as the generation of dust, thereby improving cleanliness and reliability. .

(Example) Hereinafter, an example in which the apparatus of the present invention is applied to a semiconductor wafer transfer process will be described with reference to the drawings.

A first conveyor having grooves provided at predetermined intervals for storing a plurality of plate-shaped objects such as semiconductor wafers (υ) is used.
The wafers ■ are stored between a storage container such as a wafer cassette ■ and a second storage container for processing, such as a quartz boat for heat treatment ■ having a groove for mounting a plurality of the wafers (g).
Fig. 1 shows a transfer device (a) that automatically transfers .

The configuration of this transfer device (a) will be explained below.

The wafer cassette (2) usually stores a plurality of, for example, 25 plate-shaped objects, such as semiconductor wafers (1), and is transported between processes. The wafers (2) can be arranged and stored in the cassette (2) at predetermined intervals in the thickness direction. This cassette
A mounting table (2) is provided on which a plurality of can be freely placed. This mounting table ■ slides along the rail ■ between the wafer cassette ■ mounting position where the above wafer cassette ■ is loaded and the wafer transfer position where the wafer ■ stored in the wafer cassette ■ is transferred. The wafer cassette (2) is connected to the slide mechanism (2), and the wafer cassette (2) can be freely transported to the wafer cassette (2) loading position and the wafer receiver to the transfer position. A hole smaller than the wafer cassette (2) is provided in the wafer cassette (2) placement portion of this placement table (2), and a wafer push-up portion (8) that can freely pass through this hole is provided. This push-up part (8) can be moved up and down to a higher and lower position than the mounting table 0 by a lifting mechanism (9), and the upper surface of this push-up part (8) is attached to the wafer cassette (2). A plurality of grooves are formed to engage with a plurality of stored wafers. At this time, the groove is set to a stable depth so that the wafer (2) does not fall laterally when inserted.

In addition, if a sensor is provided in each groove of the push-up part (2) and a wafer counter is configured to detect the position and number of wafers (O) stored in the wafer cassette (2), it is possible to monitor the wafer (1) at the same time. can. The sensor of the push-up part (8) is provided with a light receiver at a predetermined depth position of each groove, and judgment can be made based on whether or not a signal is detected by this light receiver.

This judgment also means normal placement. This push-up part (8
) to push up the multiple wafers 0) stored in the wafer cassette ■ and set it to the position (1'), a pair of supports, for example two gripping pieces, that hold the wafers (1) (10a) and (10b) are arranged in a connected state to a drive section (12) connected to a transfer mechanism (11).

On each opposing surface side of this gripping piece (10a) (lob),
A plurality of grooves (not shown) for holding the plurality of wafers (1) are formed in the same way as in the wafer cassette (2). Further, the cross section of the lower end of the gripping pieces (10a) and (10b) is thicker than the cross section of the upper end, and protrudes to grip the wafer (2). A gripping piece (10a) having such a shape (
10b) is a grip piece holder (13a) of the drive part (12)
(13b), this connecting portion is provided with a sliding mechanism (not shown), and this sliding mechanism allows the gripping pieces (10a) and (10b) to
3a) and (13b), each of which can be slid vertically. Moreover, this gripping piece (10a) (10
b) A coil spring (1) that limits the vertical movement of
4), for example, a gripping piece (10a) parallel to the wafer movement direction.
) (LOb) and the holders (13a) (13b). Coil spring at this time (14)
The spring force is set to such an extent that the wafer (10a) (10a) (10b) expands and contracts in response to an excessive load applied to the wafer (10b) held by the gripping pieces (10a) (10b). At least one of the gripping pieces (10a) and (10b) provided so as to be slidably movable, for example, the wafer gripping part of the gripping piece (10a) (for example, at the end of the gripping piece (10a), the wafer or means for monitoring the load on the gripping piece, e.g. gripping piece (10a) (lob).
A magnet part that is a part of a magnetic sensor (15) for detecting the positional deviation of the gripping piece (1) is provided.
A part of the upper limit sensor of the sensor (15) is disposed at a position facing the magnet part of the holder (13a) when the gripping piece (10a) is slightly raised.
A portion of the lower limit sensor of the sensor (15) is disposed at a position facing the magnet portion of the holder (13a) when the holder (13a) is slightly lowered. By providing this upper limit sensor part and a part of the lower limit sensor, the above-mentioned gripping piece (1
When the wafer ω is gripped by the gripping pieces (10a) (10b), an excessive load on the wafer α) is applied to the gripping pieces (10a) (10b).
0b), and this sliding movement causes the magnet part of the sensor (15) to approach a part of the upper limit sensor or a part of the lower limit sensor, and as a result of this approach, either part of the sensor grips the above. Piece (10a)
It is configured to detect the movement of (LOb) and output a predetermined warning to stop the operation of (LOb) to the transfer device. The interval between the gripping piece (loa) (10b) and the holder (13a) (13b) configured in this way is normally set to 0.
), and this interval can be set to any desired length. In addition, this holder (13a) (
13b) is supported by a plurality of shafts, for example, four shafts (16), which are connected to the transfer mechanism (11), and the holders (13a) and (13b) are relatively movable. For example, attach the holder (13a) to the shaft (1
The wafer cassette (7) can be moved freely along the shaft (16) by the drive of the wafer cassette (11), and the wafer cassette (11) can be moved up to above the quartz boat (2) located close to the wafer cassette (2) by the shaft drive unit installed in the transfer mechanism (11). It is movable. The quartz boat (■) can be placed at a predetermined position on a mounting table (18), and this mounting table (18) has a mounting position where the quartz boat (■) is mounted and a device for the next process. ■ Pass this quartz boat to the rail between the passing position and the passing position.
19) Transport machine that can be moved freely along +i! (20) is connected. In this way, a transfer device) is constructed.

Next, a semiconductor wafer transfer operation using the transfer apparatus having the above-described configuration will be described.

If the next process device is, for example, a heat treatment device, first, the m feed mechanism (20) is moved along the rail (12) to the above-mentioned placement position. At this mounting position, the transport mechanism (20)
The quartz boat (■) is mounted on the mounting table (18) provided in the quartz boat (18), and the quartz boat (2) is positioned on the mounting table (18). This positioned quartz boat (3) is moved to a desired wafer loading position. In addition, the other slide mechanism ■
is set at the wafer cassette ■ mounting position, and a plurality of wafer cassettes ■ are mounted on the mounting table 0. The transport mechanism (■) equipped with this wafer cassette (■) moves the receiver to the transfer position and positions it. Then, the push-up part (8), which passes through a hole formed in the mounting table (2) at the wafer cassette (1) loading position and is waiting below, is raised by the driving of the lifting mechanism (0). At this time, the plurality of wafers stored in the wafer cassette ■, for example, two
The five wafers (■) are inserted into a plurality of grooves that engage with each wafer (1) formed on the upper surface of the push-up part (8), and in a stable state where each wafer (0) does not fall laterally, the above-mentioned Push-up part (
8) rises above the wafer cassette ■, that is, (1'
) to the position. The position and number of each wafer (1) that has been pushed up is detected by a sensor, for example, a transmission type sensor (not shown) provided in each groove of the pushing up section (8). From this position and number of sheets, the holder (
13a) The gripping piece (10a) connected to (13b)
) In step (10b), the positions at which the plurality of wafers (1) are to be gripped are determined, and the gripping pieces (10a) and (10b) are gripped at suitable positions. The operation of gripping the wafer ■ is as follows: First, the wafer ■ pushed up to the position (1') is engaged with the grooves of a predetermined pitch provided in the gripping pieces (10a) (10b). The holder (13a) is moved along the shaft (16) in the direction of the holder (13b) by a shaft (17) connected to a drive mechanism (not shown). Then, when a plurality of wafers (1) are engaged with each of the grooves, the drive of the holder (13a) is stopped, and the push-up portion (3) that was pushing up the wafers (3) is lowered. At this time, the wafer (1) is held by the gripping pieces (10a) (10b) whose lower ends protrude in opposite directions, so that the wafer (2) is supported without falling. Then, in this gripping state, the drive unit (12) drives the wafer
are moved onto the quartz boat ■ and mounted on the quartz boat ■ at a predetermined position while maintaining the alignment state. Such transfer from the wafer cassette (2) onto the quartz boat (2) is repeated several times depending on the number of wafers (2).

After that, the quartz boat ■ loaded with a plurality of wafers ■ is set to be transported to the transfer position by the movement of the transport mechanism (13), and the quartz boat pass it on.

Furthermore, the processed wafers (2) from the heat treatment apparatus are transported by the quartz boat (3) to the transport mechanism (20
) moves the receiver from the transfer position to the loading position, and at this position the wafer ■ is similarly transferred between the quartz boat ■ and the wafer cassette ■.

As described in Section 1, the transfer of wafers (υ) is performed between the wafer cassette ■ and the quartz boat ■.
0b) is carried out under precisely positioned conditions, but when inserting the wafer into the wafer cassette or into the quartz boat by means of the gripping piece (10a) (tob), When the gripping piece (10a
) (10b) and wafer cassette ■ or 1 gripping piece (1
0a) If the grooves of (10b) and the quartz boat ■ do not match and there is a misalignment, the wafer (υ) cannot be transferred naturally, and if there is a slight misalignment, the end of the groove If the wafer (1) surface comes into contact with the wafer (1) and moves while rubbing, or if the positional deviation is severe, the above transfer operation may not be possible, or in the worst case, the wafer (1) may be damaged and the wafer (1) may be damaged. This will damage the pattern being used.

Therefore, the gripping piece (10a) (1
0b) can be moved up and down somewhat with respect to a predetermined position, for example, a holder (13a) (13b), and a gripping piece (1oa ) (10b) is provided with a coil spring (14) having a desired spring force.
The wafer ω pushed up by the gripping piece (10a) (1
0b). At this time, 1 gripping piece (LOA) (10
If the grooves in b) and the grooves in the push-up part (8) are slightly misaligned, hold the wafer (υ) inserted in the groove in the push-up part (8) with the gripping pieces (10a) (10b). When the wafer is gripped and inserted, a load is applied due to friction between the wafer (υ) and the groove of the push-up section 0, and this load causes the coil spring (
14) is extended, the sensor (15) provided at the upper end of the gripping piece (10a) detects the extension of the coil spring (14), and recognizes that an excessive load is being applied to the wafer (1). Then, the insertion or ejection operation of the wafer (2) is stopped. Next, the operation of correcting the displacement of the wafer (1) is executed by using software, such as moving the gripping piece (LOA) (10b) in the direction of correcting the displacement of the wafer (0). After this correction, the wafer (1) is inserted and taken out naturally,
The transfer operation can be performed without damaging the pattern formed on the surface of the wafer 0.

Further, the coil spring (14) is used not only to monitor the load applied to the wafer ω, but also to monitor the load applied to the wafer ω.
a) If the lower end of (10b) comes into contact with an obstacle,
When the coil spring (14) contracts, the sensor (
15), it is possible to detect the upper limit and take safety measures such as stopping the operation.

In the above embodiment, the wafer (1) or the gripping piece (LOA) (
The means for monitoring the load applied to 10b) is composed of a coil spring that expands and contracts in the vertical direction at the connection part of the gripping piece, and a sensor that detects the positional deviation of the gripping piece in the direction of expansion and contraction of this coil spring. For example, the shaft (16) cantilevered at one end of the shaft (16) in the direction of the transfer mechanism (11).
A strain sensor is installed to detect the deflection of the shaft (
16) A similar effect can be obtained by detecting the deflection of the shaft (16) using the strain sensor, which is applied to the load applied downward to the wafer (■) when the wafer (G) is gripped by the support plate provided on the other end. be able to.

As described above, according to this embodiment, by providing the means for monitoring the load applied to the plate-like object or the gripping piece,
Detects when an excessive load is applied to a plate-like object or gripping piece, and prevents damage or dust generation to the plate-like object or objects in contact with it, improving cleanliness and reliability. becomes possible.

Furthermore, when transferring semiconductor wafers, the pattern formed on the wafer surface is not damaged, and the yield can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a transfer device for explaining one embodiment of the device of the present invention. 1... Wafer, 4... Transfer device. 10a, 10b...Gripping piece, 11...Transfer mechanism, 13a, 13b...Holder, 14...
Coil spring, 15...sensor. Patent applicant Chill Yamanashi Co., Ltd.

Claims (3)

[Claims] (1) A plurality of plate-like objects are aligned and stored in a first storage container at predetermined intervals, and the supported plate-like objects are aligned by relative movement in opposite directions of a pair of opposing gripping pieces. The device maintains and grips the object and transfers it to a second storage container, characterized by comprising means for monitoring the load applied to the plate-like object or the gripping piece during the process of transferring the plate-like object. Transfer device. (2) A patent characterized in that the means for monitoring the load comprises a coil spring that expands and contracts in the vertical direction at the connecting portion of the gripping piece, and a sensor that detects a positional deviation of the gripping piece in the direction of expansion and contraction of the coil spring. A transfer device according to claim 1. (3) A claim characterized in that when a load is applied to the plate-like object or the gripping piece, the transfer operation is stopped, and the plate-like object and the gripping piece are relatively moved to a position where the load is removed. Transfer device according to item 1.