JPH01295435A - Wafer transfer apparatus - Google Patents

Abstract

PURPOSE:To prevent contamination of circuit forming surfaces, by making it possible to rotate a table on which a jig for an initial handling or a final handling is mounted in the planar direction, and containing neighboring wafers within the jig for the final handling under the state wherein the circuit forming surfaces are made to face each other and the rear surfaces are made to face each other. CONSTITUTION:A stage 2 is moved leftward. When a jig 14 for a final handling at the center is positioned at a part directly beneath wafer guides 5a and 5b, a wafer which is held with a pusher 11 is lowered and contained in the jig 14 for the final handling. Wafers are already contained from a jig 13b for a second initial handling in the jig 14 for the final handling as an every-other-sheet basis. The new sheet is inserted between these wafers. At this time, the wafer is turned by 180 degrees. Therefore, all the wafers are arranged in the state wherein circuit forming surfaces C of the neighboring wafers are made to face each other, and the rear surfaces are made to face each other. In this way, auto-doping of impurities which are attached to the rear surface into the circuit forming surfaces can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a technique that is effective when applied to transfer of semiconductor wafers (hereinafter simply referred to as wafers) in the manufacturing process of semiconductor devices.

[Conventional technology]

An example of a description of wafer transfer technology is "Electronic Materials Special Edition, Super LS+I Manufacturing/Testing Equipment Guidebook JP JP 109-116," published by Kogyo Kenkyukai Co., Ltd., November 15, 1980.

Pll of the above-mentioned document describes matters to be noted when transferring wafers between cartridges (jigs) (wafer handling) during wafer processing.

In the manufacturing process of semiconductor devices, wafers are usually processed using a jig in which a large number of wafers are housed in parallel with their circuit-forming surfaces aligned in one direction.

Therefore, in the wafer alignment technique described above, as shown in FIG. 7, adjacent wafers in the jig have their circuit forming surfaces C and back surfaces R facing each other.

[Problem to be solved by the invention]

However, in a wafer in which impurities are also deposited on the back surface R of the wafer, auto-doping of the impurity occurs from the back surface R of the wafer to the circuit formation surface C of the wafer facing the back surface R of the wafer due to the subsequent diffusion process. There are many cases.

Therefore, when wafers with impurities deposited on their back surfaces are aligned as shown in FIG. causing heautodoping,
There was a high possibility that it would cause contamination of the circuit forming surface C (
(See Figure 7).

The present invention has been made in view of the above-mentioned problems, and its purpose is to automatically change the alignment direction of adjacent wafers during wafer handling, and to automatically remove impurities attached to the back surface of the wafer. It is an object of the present invention to provide a wafer manufacturing technology with high product reliability by preventing contamination of a circuit forming surface caused by doping.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, the table on which the handling source or handling jig is placed can be rotated in a plane direction, and by rotating the table by a predetermined angle, for example, 180 degrees, each time a wafer is handled, the table can be rotated in parallel in the handling target jig. Matching wafers are accommodated with their circuit forming surfaces facing each other and their back surfaces facing each other.

[Effect]

According to the above-mentioned method, the wafers are arranged and housed with their back faces facing each other, that is, back to back, in the handling jig, so that impurities on the back side, which can be a source of contamination, only auto-dope between the back faces of the wafers. , the clean state of the circuit forming surface can be maintained. Therefore, the yield of wafers can be improved and product reliability can be improved.

〔Example〕

FIG. 1 is a partial plan view showing a rotating part of a stage of a wafer transfer apparatus according to an embodiment of the present invention;
Figures (a), (b), and (C) are a front view, a plan view, and a side view showing the schematic configuration of the wafer transfer device, respectively, and Figures 3 (a) to (C) are illustrations of the handling of this embodiment for convenience. Explanatory diagram showing the outline of the procedure, Figures 4(a) to (1)
) is an explanatory diagram showing the wafer handling method according to the embodiment, FIG. 5 is a partial perspective view showing the wafer guide and wafer holder, and FIGS. 6(a) and (b) are the wafer ( It is an explanatory view showing a dumbfounded state.

As shown in FIG. 2, the wafer transfer apparatus 1 of this embodiment has a stage 2 that can slide in the longitudinal direction, and on the stage 2 there are three jig mounting points N3a.
, 3b, and 3c.

A stand 4 is erected from approximately the center side of the stage 2, and the stand 4 includes a pair of wafer guides 5a,
5b is provided protrudingly. A pair of wafer guides 5a, 5b
As shown in FIG. 5, guide grooves 5a are formed on the surfaces facing each other in a direction perpendicular to the stage 2.
5b, and the wafer 7 is movable in the vertical direction with its side ends supported by the guide grooves 5a and 5b. A pair of wafer holders 3a, 8b are formed protrudingly below the wafer guides 5a, 5b, and a support groove IQa is formed in a straight line perpendicular to the axial direction in a part of the cylindrical peripheral surface of the wafer holders 3a, 3b. , 10b are formed. The wafer holders 3a and 3b are structured to be rotatable around their axes, and in a normal state (FIG. 6(a)), the support grooves toa and iob are connected to the wafer guide 5.
The wafer 7 is in a linear positional relationship that is continuous with the guide grooves 5a and 3b of the guide grooves 5a and 5b, and the wafer 7 is
a, 3b can be passed in the vertical direction.

On the other hand, when the wafer 7 is held by the wafer holders 3a and 3b, the wafer holders 3a and 3b are rotated by a predetermined angle, and the support grooves 10a and 10b are also tilted at a predetermined angle accordingly (see Fig. 6). )). In this case, the wafer 7 is held in the support grooves 1Qa, 10b and is prevented from falling downward.

The wafer guide 5a is placed on the stage 2.

5b and below the wafer holders 3a and 3b, a button 11 that can move up and down is arranged to hold a plurality of wafers 7.
It has a structure that allows it to be raised or lowered while standing upright.

Three jig placement parts 3a and 3b on the stage 2.

Two locations 3a and 3c at both ends of 3C have a structure of rotary tables 12a and 12b, and are configured to be rotatable in units of at least 180 degrees. Although details of such a rotation drive mechanism for the rotary tables 12a and 12b are not shown in the drawings, it can be easily realized by installing a drive motor or the like within the stage 2.

Next, the outline of the wafer transfer technique of this embodiment will be explained using FIGS. 3(a) to 3(C). For convenience of explanation, the figure shows the case where three wafers 7 are accommodated from each jig, but in the actual wafer processing process, for example, 25 wafers may be accommodated. It is possible to handle a large number of wafers 7. In addition, 138
13b represents a first handling jig, 13b represents a second handling jig, and 14 represents a handling target jig. Further, in the wafer 7, the side indicated by diagonal lines in the figure is the circuit forming surface C.

First, jigs 13a and 13b containing every other wafer 7 are set at both ends, and an empty handling target jig 14 is set at the center. At this time, the jigs 13 at both ends
Ueno\7 in a and 13b is in a state in which the circuit forming surface C is located above in the plane direction of the figure. In this state, the wafer 7 is transferred from the jig 13b on the right side in the figure to the jig 14 in the center.
move.

At the same time, the jig 13a on the left side of the figure is turned over by 180 degrees to change the orientation of the wafer 7 (FIG. 3(a)).

Subsequently, the wafer 7 is transferred from the inverted left jig 13a to the center jig 14. At this time, the central jig 14
Inside, the wafer 7 already transferred from the right jig 13b is 1
The wafers 7 are housed one by one, and from the jig 13a on the left, one wafer is inserted between each of the wafers 7 that are already housed.
(Fig. 3(b)).

By taking the above-mentioned accommodation procedure, in the central jig 14, as shown in FIG. 3(C), the adjacent wafers 7 have their circuit forming surfaces C facing each other and their back surfaces R facing each other.

A case where this is realized by the configuration of the above-mentioned transfer device 1 will be explained with reference to FIG. 4.

The first and second handling source jigs 13a and 13b each containing a wafer 7 are set on the jig placement a'1s3a and 3C at both ends of the stage 20, and an empty handling destination jig 14 is set in the center of these. When set, the stage 2 moves to the left in the figure (FIG. 4(a)), and the wafer guides 5a and 5b are positioned directly above the second handling jig 13b (FIG. 4(a))). .

In this state, the bushing 11 rises from below the stage 2 and lifts up the wafer 7 in the second handling jig 13b. At this time, the wafer 7 is placed in the wafer holder 8.
a, 8b support groove 10a.

tab, and guide groove 5 of wafer guides 5a, 5b.
a, (its side edge is supported by ib (Fig. 6(a)
reference). When the wafer 7 is raised to a predetermined position in this manner, the wafer holders 8a and 8b are rotated, and the support grooves lOa and 10b of the wafer holders 3a and gb are set at a predetermined inclination angle (see FIGS. 6 and others). In this state, the bush is 1
When the wafer 1 is lowered (FIG. 4(C)), the wafer 7 is prevented from lowering by the support /jtlOa, 10b, and the wafer 7 is moved to the wafer holder 8a.

Stay within 8b.

At the same time as this work, the first handling jig 1
3a is rotated by 180 degrees by the rotary table 12a, and the wafer 7 in the jig 13a is also in a state in which the circuit forming surface C and the back surface R are reversed (FIG. 3(C)(d)).

Subsequently, the stage 2 is moved to the right in the figure, and the central handling target jig 14 is again positioned directly below the wafer guides 5a and '5b (see [e] in the figure). Here, the pusher 11 is raised from the stage 2 surface, and the wafer 7 held by the wafer holders 8a and 8b is slightly raised. Subsequently, the wafer holders 8a, 8b are rotated,
Support groove 10a.

When the wafer 7 is allowed to pass through the interior of the bushing 10b, the wafer 7 supported by the bushing 11 gradually descends, and the wafer 7 is accommodated in the handling jig 14 (see (f) in the same figure). )). At this time, as explained in FIG. 3, the wafers 7 are housed one by one.

From the state shown in FIG. 8 (8), the stage 2 is again moved to the right in the figure, and the first handling jig 13a is positioned directly below the wafer guides 5a, 5b. At this point, the button 11 rises from the second stage.
), the wafer 7 in the first handling jig 3a is lifted up and held by the wafer holders 3a and 3b in the same manner as above (( ) in the figure).

Next, the stage 2 moves to the left in the figure, and the center handling jig 1 is placed directly below the wafer guides 5a and 5b again.
4 is positioned, the wafer 7 held in the wafer holders 8a and 3b is lowered again by the pusher 11 (see (lk) in the same figure), and the wafer 7 is accommodated in the handling destination jig 14 (FIG. 1D). (Figure (1)). At this time, every other wafer 7 from the second handling source jig 13b described above is already accommodated in the handling destination jig 14, and during this time, the first handling source jig 1
The wafers 7 from 3a are inserted and accommodated. Here, since the wafers 7 from the first handling jig 13a, which are lowered and accommodated at this time, are inverted by 180 degrees, all the wafers 7 accommodated in the handling destination jig 14 are Adjacent wafers 7 are in a state where their circuit forming surfaces C face each other and their back faces R face each other (back face facing alignment).

The wafers 7, which have been rear-to-back aligned in the handling destination jig 14 in this manner, are transferred to the next cleaning process, diffusion process, etc. At this time, impurities attached to the back surface R of the wafer 7 may float in the high-temperature environment of the diffusion furnace and reach the adjacent wafers 7. However, according to this embodiment, the back surfaces R of the wafers 7 Since they are arranged so as to face each other, autodoping of impurities to the circuit forming surface C side can be effectively prevented.

Therefore, contamination of the circuit forming surface C caused by auto-doping of impurities on the back surface R of the wafer 7 during the diffusion process or the like is effectively prevented, and highly reliable wafer processing becomes possible.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, in the above embodiment, the first and second handling source jigs and handling destination jigs are arranged on the stage 2, but it may be configured with only a single handling source jig and a handling destination jig. . In this case as well, the same effect as in the above embodiment can be obtained by using the jig mounting ff1flF15 on which at least one of the jigs is mounted as a rotary table structure.

Further, in the embodiment, a case has been described in which only the first handling jig 13a is rotated, but the second handling jig 13b or the handling destination jig 14 may be rotated.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

In other words, by making the table on which the handling source or handling destination jig is rotatable, adjacent wafers can be accommodated in the handling destination jig with their circuit forming surfaces facing each other and their back surfaces facing each other. Therefore, autodoping of impurities attached to the back surface to the circuit formation surface can be prevented, and product reliability in the wafer manufacturing process can be improved.

[Brief explanation of the drawing]

FIG. 1 is a partial plane view showing the rotating part of the stage of a wafer transfer device according to an embodiment of the present invention, and FIGS. 2(a), (b), and (C) are schematic configurations of the wafer transfer device, respectively. Figures 3(a) to (C) are explanatory diagrams showing an outline of the handling procedure of this example for convenience, and Figures 4(a) to (1) are illustrations of the actual handling procedure. An explanatory diagram showing a wafer handling method according to the example. FIG. 5 is a partial perspective view showing a wafer guide and a wafer holder in the example. FIGS. FIG. 7 is an explanatory diagram showing the state in which wafers are aligned in a jig in the prior art. l... wafer transfer device, 2... stage,
3a, 3b, 3c...Jig mounting section, 4...Stand, 5a, 5b...Wafer guide, 5a, 5b...
Guide groove, 7...Wafer, 8a, 8b...Wafer holder, 10a, 10b...Support groove, 11...Button, 12a, 12b...Rotary table, 13a...
First handling jig, 13b... Second handling jig, 14... Handling destination jig, C...
・Circuit formation surface, R...back side. Agent Patent Attorney Daiwa Tsutsui Figure 4 Figure 5 a Figure 7

Claims (1)

[Claims] 1. A wafer transfer device that takes out a semiconductor wafer in a handling source jig on a stage and stores it in another handling destination jig, the device comprising: a handling source jig and a handling destination jig; The table on which the wafers are placed is rotatable, and each time a wafer is handled, the table is rotated by a predetermined angle, and adjacent wafers are accommodated in the handling jig with their circuit-forming surfaces facing each other and their backs facing each other. A wafer transfer device characterized by making it possible. 2. The wafer transfer apparatus according to claim 1, wherein the table is rotated by 180 degrees each time a wafer is handled.