JP2856843B2 - Wafer alignment apparatus and wafer alignment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a wafer alignment apparatus and a wafer alignment method.

(Prior Art) Japanese Patent Publication No. 1-59 describes a method in which the orientation flats of a plurality of wafers stored in a carrier are adjusted at once by a rotating roller.
There is 739 publication.

Japanese Patent Application Laid-Open Nos. 63-13344 and 64-743 show that the same number of photodetectors as the number of wafers housed therein are provided to detect the presence or absence of a plurality of wafers housed in a carrier at once.
There is an official gazette.

(Problems to be Solved by the Invention) According to the technique of the above-mentioned document, when the rotating roller and the peripheral edge of the wafer are brought into contact with each other and the wafer is rotated, the wafer comes into contact at two places, an upper part and a lower part in a groove of the carrier, and the wafer edge part A large amount of so-called chipping occurs, in which minute parts of the wafer break or the film adhered to the wafer by CVD or the like peels off. Has the problem of lowering

When trying to count wafers after orientation flat alignment using the technique of the latter document, the movement range in the thickness direction of the wafer rotated by the rotation roller for orientation flat alignment moves up to about 2 mm from the center of the carrier groove. I do.

In order to insert the photodetector within the 3/16 inch (4.76 mm) wafer interval, which is the groove pitch of a commonly used carrier,
This photodetector has a thickness that can be made thin, for example, 2 mm.
Then, the distance between the wafer and the photodetector is only about 1 mm.

In this state, when the photodetector is moved so as to be inserted between the wafers, the wafer whose displacement is larger than the center position of the groove of the carrier contacts the photodetector at the edge portion of the wafer, and the chipping of the wafer greatly occurs. As described above, there is a problem that the yield of the semiconductor element is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wafer alignment apparatus and a wafer alignment method that can reduce chipping generated when aligning a wafer orientation flat and improve the yield of semiconductor devices.

[Configuration of the invention]

(Means for Solving the Problems) The invention according to claim 1 of the present invention is a holding member for vertically storing a plurality of wafers having an orientation flat at a part of a peripheral edge, and a holding member for storing a plurality of wafers in the holding member. In a wafer alignment device having a pair of rollers that abut against the lower peripheral edge of the wafer and rotate the wafer to align the orientation flat in one direction, the rollers are provided with annular grooves for arranging the wafers at a predetermined pitch. A light emitting element and a light receiving element are provided on the inner side surface of the groove corresponding to the annular groove, and a wafer detector for detecting the presence / absence and position of the wafer is provided so as to be movable up and down between the pair of rollers.

The invention according to claim 2 includes a pair of rollers having an annular groove portion for arranging the wafers at a predetermined pitch in a state in which a plurality of wafers having an orientation flat on a part of a peripheral edge are stored in a vertical state in a holding member. A step of contacting the lower edge of the wafer and rotating the wafer to align the orientation flat in one direction; and after this step, while the wafer is held by the rollers, light is emitted onto the inner surface of the groove corresponding to the annular groove. Raising a wafer detector provided with an element and a light receiving element between the pair of rollers, inserting a peripheral edge of the wafer into the groove, and detecting presence / absence and a position of the wafer. And

(Operation) According to the first aspect of the present invention, the movement of the wafer in the thickness direction is restricted by the annular groove provided in the roller,
In addition to being able to reduce the chipping that occurs when the wafer contacts the holding member during orientation flat alignment,
After aligning the orientation flats, raise the wafer detector between the pair of rollers, and insert the peripheral edge of the wafer into the groove to detect the presence and position of the wafer so that the wafers are arranged at a predetermined pitch in advance. Accordingly, it is possible to reduce chipping generated when the wafer detector comes into contact with the wafer, thereby improving the yield of semiconductor devices.

According to the second aspect of the invention, it is possible to smoothly perform the alignment flat alignment and the detection of the presence / absence and position of the wafer in a state where chipping is reduced as much as possible, thereby improving the throughput and the yield of the semiconductor element. Can be improved.

(Embodiment) An embodiment of the wafer alignment apparatus of the present invention will be specifically described below with reference to the drawings.

In FIG. 1, a plurality of wafers 1 have a wafer size of 6 inches, an outer diameter of 150 mm, and an oriental flat portion length of 60 mm. The guides 2 are arranged vertically above an intermediate portion of a guide (holding member) 2 made of a soft resin such as fluororesin. Is inserted into a groove 3 having a U-shaped cross section as viewed from above, and the wafer 1 is housed vertically and rotatably in a vertical plane. 5 is mounted on a mounting table 4 having the same. The opening 5 has a groove 7 provided so as to fit a plurality of the wafers 1 therein, and a push-up portion 6 provided so as to be capable of storing and raising the wafer 1 by a lifting mechanism (not shown). 2, two rollers 10 and a wafer detector 30 are provided, and the details will be described with reference to FIG.

The two rollers 10 are made of a soft resin such as a fluororesin having a diameter of 20 mm, and are provided with an annular groove 13 as shown in FIG. A pulley 21 is connected to a rotating shaft of a motor 20 provided below the two rollers 10, and a belt is provided between the pulley 21 and the two rollers 10.
The two rollers 10 can be rotated in the same direction by the rotation of the motor 20. In addition, the above 2
The roller mechanism 12 including the roller 10 and the motor 20 is configured to be able to move up and down by a lifting mechanism (not shown).

The interval between the two rollers 10 is configured to be adjustable according to the size of the wafer 1 and the length of the orientation flat.

Next, a wafer detector 30 is provided between the two rollers 10 and in parallel with the rollers 10.

The wafer detector 30 is formed by molding a ceramic or resin, for example, Delrin (trade name).
A plurality of groove portions 32 are provided at positions corresponding to the respective groove portions 13, and a detecting element pair 38 including a light emitting element 34 and a light receiving element 36 as shown in FIG. The sensing element pair 38 is a sensor unit for detecting the presence or absence of a wafer, and has an electrical signal output electrically connected to a signal processing unit 40.

The pitch of the groove 32 of the wafer detector 30 is about 3/16 inch, which is the groove pitch of the wafer carrier in which the wafer is stored.
The width A of the groove 32 is about 2.7 mm, and the thickness B of the projection 31 is 2 mm.

Since a plurality of light emitting elements 34 and light receiving elements 36 cannot be coaxially arranged within 2 mm of the thickness B of the convex portion 31, the sensing element pairs 38 are alternately arranged as shown in FIG. I have.

Since the wafer detector 30 is provided between the two rollers 10, the width W of the wafer detector 30 is 15 mm, and the thickness B of the projection 31 is
It is difficult to set the depth C of the groove 32 to 5 mm or more in consideration of the mechanical strength of the convex portion 31 made of Delrin, deformation after molding of Delrin, and other temporal deformation. In this embodiment, the depth C of the groove 32 is
Is set to the above-mentioned limit of 5 mm.

For this reason, it is desirable that the wafer detector 30 be fitted to the orientation flat position aligned with the plurality of wafers 1 in order to perform accurate wafer detection.

Next, a description will be given of a method of aligning the orientation of a plurality of wafers 1 and the wafer counting method for detecting the presence / absence and position of the plurality of wafers 1 by the apparatus of the embodiment.

A roller mechanism 12 is provided so that two rollers 10 contact the lower peripheral edge of the plurality of wafers 1 stored in the guide 2.
Is raised by a lifting mechanism (not shown).

Then, the motor 20 is rotated to rotate the two rollers 10 in the same direction via the pulley 21 and the belt 22.

The plurality of wafers 1 are rotated in the annular groove 13 by contact with the annular groove 13 provided on the rotating roller 10, and continue to rotate until the orientation flat is lower.
When the orientation flat portion of the wafer 1 is lower, the orientation flat portion is separated from the roller 10, and the rotation of the wafer 1 is automatically stopped. After the orientation flats of all the wafers 1 are aligned, the rotation of the motor 20 is stopped, and the rotation of the rollers 20 is stopped. The lower ends of the wafers 1 are arranged at the pitch of the annular groove 13. When the wafer detector 30 is raised by an elevating mechanism (not shown), the wafers are detected without contacting the orientation flats of the plurality of aligned wafers 1. The groove 32 of the container 30 is fitted.

Then, when infrared light is emitted from the light projecting element 34 provided in the wafer detector 30, the infrared light enters the light receiving element 36 of the groove 32 in which the wafer 1 is fitted, facing the light projecting element 34. Instead, an electric signal proportional to the amount of light received by the light receiving element 36 is transmitted to the signal processing unit 40, and the presence or absence and position of the wafer 1 are detected.

In the same manner as described above, the presence / absence and position of the plurality of wafers 1 in all the groove portions 32 are instantaneously detected, a signal is transmitted to a next process device (not shown), and a display is provided on a motor device (not shown).

Next, the push-up portion 6 is lifted by a lifting mechanism (not shown) so that the peripheral portion of the wafer 1 is fitted into the groove 7 of the push-up portion 6 disposed on both sides of the two rollers 10, and the plurality of wafers 1 With the orientation flats aligned, the wafer 1 is pushed up above the guide 2 at a time, and the wafer is transferred to the next step by a wafer check (not shown).

When aligning the orientation flat as described above, the wafer 1
Since there are few portions in contact with the guide 2 and the inclination angle of the wafer 1 is also small, chipping of the wafer is greatly reduced.

Also, the lower end of the plurality of wafers 1 is an annular groove of the roller 10.
It is arranged at a pitch of thirteen. Even if the wafer detector 30 is inserted and moved between the wafers 1, the wafer 1 and the wafer detector
No contact occurs at 30 and no chipping of the wafer occurs.

The present invention is not limited to the above embodiment,
Various modifications can be made within the scope of the present invention.

In the above embodiment, a guide 2 for accommodating a plurality of wafers 1
Although the guide 2 is used, a wafer carrier made of a resin for accommodating 25 wafers, for example, a fluororesin may be used instead of the guide 2. In this case, after the orientation flat alignment and wafer counting are completed, the roller mechanism 12 and the wafer detector 30 are lowered by an elevating mechanism (not shown), and the above-described carrier in a state where a plurality of wafers 1 are stored is moved to the next step by, for example, a carrier transport device. It may be transported. The pitch of the grooves 32 of the wafer transfer device 30 is not limited to 3/16 inch, but may be 1/4 inch or any other size.

Further, when the aligned orientation flat position is, for example, upward, one of the two rollers 10 is replaced with one of the wafers 1.
The roller 10 can be moved upward by rotating the roller 10 a predetermined height by raising the roller 10 at a predetermined height from the position where the orientation flat has been aligned.

Further, in the present embodiment, the description has been given using the transmission type as the wafer detection element pair 38, but it goes without saying that a reflection type detection element pair may be used.

As the light emitting element, a light emitting diode, and as the light receiving element, a photodiode, a phototransistor, a solar cell type thin detector, or the like can be used. The number of rotating rollers 10 for aligning the orientation flats is not limited to two, but may be one or three or more.

The wafer detection unit 30 may be provided on at least one side of the push-up unit 6.

Further, the application example of the above-described wafer alignment apparatus can be effectively used in each process of a semiconductor device, and can be used for a heat treatment apparatus, an etching apparatus, an ion implantation apparatus, an inspection apparatus, a resist coating apparatus, a carrier stocker apparatus, and the like.

For example, the present invention can be used in a process of transferring a plurality of wafers from a plurality of carriers to a heat treatment boat in a horizontal heat treatment apparatus or a vertical heat treatment apparatus.

〔The invention's effect〕

In short, according to the present invention, the following excellent effects can be obtained.

(1) According to the first aspect of the present invention, the movement of the wafer in the thickness direction is restricted by the annular groove portion provided on the roller, and chipping generated when the wafer comes into contact with the holding member at the time of aligning the orientation flat is reduced. After aligning the orientation flat, raise the wafer detector between a pair of rollers and insert the peripheral edge of the wafer into the groove to detect the presence and position of the wafer beforehand. , The chipping that occurs when the wafer detector contacts the wafer can be reduced, and the yield of semiconductor devices can be further improved.

(2) According to the second aspect of the invention, alignment of the orientation flat and detection of the presence / absence and position of the wafer can be sequentially and smoothly performed in a state where chipping is reduced as much as possible. The yield of the device can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a wafer storage unit of an embodiment of a wafer aligning apparatus according to the present invention, FIGS. 2 and 3 are partial explanatory views of FIG. 1, FIG. 4 and FIG. It is a wafer detector explanatory drawing. DESCRIPTION OF SYMBOLS 1 ... Wafer, 2 ... Guide 6 ... Push-up part, 10 ... Roller 20 ... Motor, 30 ... Wafer detector 40 ... Signal processing part

Claims (2)

(57) [Claims] A holding member for vertically storing a plurality of wafers having an orientation flat at a part of a peripheral edge thereof, and a lower edge of the wafer accommodated in the holding member is brought into contact with the holding member, and the wafer is rotated to remove the orientation flat. In a wafer alignment apparatus having a pair of rollers that align in one direction, an annular groove for arranging wafers at a predetermined pitch is provided on the roller, and a light emitting element and a light receiving element are provided on the inner surface of the groove corresponding to the annular groove. A wafer alignment device, wherein a wafer detector for detecting the presence and position of a wafer is provided between the pair of rollers so as to be able to move up and down. 2. A pair of rollers having an annular groove for arranging said wafers at a predetermined pitch in a state in which a plurality of wafers having an orientation flat at a part of a peripheral edge are housed in a holding member in a vertical state. Abutting the peripheral edge, rotating the wafer to align the orientation flat in one direction, and after this step, with the wafer held by the rollers, the light emitting element and the light receiving element on the inner surface of the groove corresponding to the annular groove. Raising a wafer detector provided with an element between the pair of rollers, and inserting a peripheral edge of the wafer into the groove to detect the presence / absence and position of the wafer. .