JPH1098096A - Semiconductor wafer cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the contacting surface of the periphery of a wafer with a cassette main body to an absolute minimum in area by a method, wherein the underside of the wafer is held only with wafer separating ribs, provided to both the side walls and inner wall pillar of a cassette. SOLUTION: A semiconductor wafer W is inserted into a cassette, passing through near the center of a groove 20 on a left side between two adjacent ribs 21. At this point, the wafer W is inserted, so as to approach inner wall pillars 13 and 32 or a frame 15 breaking away from the upper and lower wafer separating rib 21. The peripheral tip Wa of the wafer W reaches to a rib 33 breaking away from a loading/unloading device. Then, as shown by chain double-dashed line, the wafer W is held at two points on its one side with the ribs 33 and 21. That is, both the sides of the wafer W are held with the four ribs 33, 33, 21 and 21. At this point, even if the wafer W deflects slightly, it is restrained from coming into contact with a fall preventing 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to
The present invention relates to a semiconductor wafer cassette suitable for housing and transporting a semiconductor wafer having a diameter as large as zero.

[0002]

2. Description of the Related Art Semiconductor wafers extremely dislike contamination,
In the manufacturing process, a cassette for semiconductor wafers (hereinafter referred to as
(Hereinafter simply referred to as a cassette) and transported in a state of being isolated from the surroundings. Thereafter, various chemical cleaning, drying, and the like are performed.

Further, it is preferable that the contact area between the semiconductor wafer and the cassette is as small as possible. Therefore, the cassette has a structure in which a narrow range of only the peripheral portion of the wafer is held.

Here, a conventional cassette for transporting semiconductor wafers, as shown in FIG. 10, is formed so that a groove 3 having a predetermined width 1 is formed on inner surfaces 2a of both side walls 2, 2 of the cassette body 1. It has a plurality of wafer separating ribs 4 protruding inward, and the ribs 4 separate the wafers W from each other and hold them independently. When carrying the wafer W using the cassette body 1, the wafer W is often carried out in the state shown in FIG.

The wafer W is automatically loaded and unloaded from the cassette body 1 using an automatic loading and unloading device 5 as shown in FIG. In the automatic wafer loading / unloading device 5, the cassette body 1 is erected on the elevating platform 6 so that the wafers W are stacked in the vertical direction, and the wafer W in one cassette body 1 is transferred to the carrier 7 , The sheet is taken out one by one, conveyed to the other cassette main body 1 placed on the other elevating table 8, and stored in the groove 3. In this case, the elevating tables 6 and 8 move up and down by one pitch every time a wafer is taken out one by one, so that all the wafers W in one cassette 1 can be accommodated in the other cassette 1.

[0006]

However, in recent years,
Semiconductor wafers having a diameter as large as φ300 are about to enter the market, and the specifications of wafer cassettes used for transporting the semiconductor wafers are being standardized.

According to this, when carrying this kind of semiconductor wafer, unlike the conventional case of carrying a semiconductor wafer W, as shown in FIG. 11, the cassette body 1 has an opening through which the wafer W is taken in and out. It is defined that the wafer W is transported with the unit 9 laid down. In this case, the wafer W is transported in the same posture, that is, in a horizontal state.

However, when a wafer W having a diameter of 300 is conveyed only in a horizontal state with the opening 9 laid sideways, the wafer W jumps out of the opening 9 of the cassette body 1 when the conveyance starts or stops. Is also conceivable.

Further, when such a semiconductor wafer W is held in the cassette body 1 as in the prior art, the contact area between the semiconductor wafer W and the cassette body 1 increases, and the friction of the contacted portion causes the surface of the wafer W to adhere to the surface of the wafer W. There was a risk of being scratched.

The present invention has been made in view of such circumstances, and in particular, φ3
When a semiconductor wafer having a large diameter of about 00 is accommodated in the cassette main body, the contact area between the peripheral portion of the wafer and the cassette main body can be kept as small as possible, and the wafer can be prevented from popping out when the transfer is stopped. To prevent and even
It is an object of the present invention to provide a semiconductor wafer cassette in which even if one wafer falls off from a predetermined groove, a wafer stored in a lower part is not damaged.

[0011]

According to the present invention, the lower surface of one semiconductor wafer is held by, for example, ribs provided at four locations. Other ribs for preventing falling off are provided near the two ribs so that the wafer can be locked immediately when the wafer comes off.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A rib for holding a semiconductor wafer according to the present invention is provided on each side wall, one on each side wall, and two on a back wall column opposite to the opening for taking in and out the wafer. Also, when the peripheral edge of the semiconductor wafer is detached from the two ribs of the back wall pillar, the dropped peripheral edge is locked by the rib for preventing falling off before colliding with another wafer. It is necessary to determine the position where the rib for preventing the falling off is formed.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a semiconductor wafer cassette 10 according to one embodiment of the present invention.

The wafer cassette 10 is made of a synthetic resin having excellent chemical resistance such as fluororesin or ABS resin or a general-purpose synthetic resin, and is formed by injection molding or assembly.

The wafer cassette 10 is provided between a pair of a top plate 11 and a bottom plate 12 which are arranged vertically.
The arc-shaped side walls 13 and 14 and the square frame 15 are erected to form a cassette body 16. An opening 17 for taking in and out the wafer W in the horizontal direction is formed in the front part of the cassette body 16, and an opening 18 serving as an optical path of an optical sensor is provided in a rear part, that is, on both sides of the frame 15.
19 are formed. Further, in order to secure a space for an arm of the automatic wafer loading / unloading apparatus, the frame-shaped body 1 is provided.
5, a substantially rectangular opening 15a is formed at the center.

As shown in FIGS. 2 to 4, a plurality of wafer separating wafers 20 are formed on the inner surfaces of the side walls 13 and 14 near the opening 17 so as to form grooves 20 having a predetermined width l. The ribs 21 are provided in a line in the vertical direction.

The wafer separating rib 21 is formed to be inclined upward by α so that the inside of the diameter is higher than the outside of the diameter. Therefore, by providing such an inclination, even when, for example, an unprocessed wafer having a sharp corner is held on the rib 21, the rib is provided at a portion slightly larger than the center of the diameter from the peripheral end surface of the wafer. Since the cassettes come into contact with each other, the cassette is not scraped by the corners of the wafer, and the generation of particles is prevented. Also,
Scratching of the wafer is also prevented.

The rib 21 has a substantially arc-shaped step 22 formed on the upper surface thereof. Upper step surface 2 constituting step section 22
As shown in FIG. 2 and FIG. 3, the width of M3 is increased as it approaches the opening 17. Therefore,
When the wafer W is guided from above the rib 21 in the groove 20, the peripheral edge of the wafer W comes into contact with the arc-shaped step portion 22, and is prevented from jumping out to the opening 17 side.
On the other hand, the lower step surface 24 constituting the step section 22 has a bulge 25
Are formed, thereby reducing the contact area with the lower surface of the wafer. The upper surface 23 of the step 22
Needs to be higher than the bulging portion 25.

The frame 1 is opened from the openings 17 of the side walls 13 and 14.
5 are provided with ribs 26, 2 for preventing falling off, respectively.
6 are formed in a line in the vertical direction at a predetermined pitch. As shown in FIG. 5, the rib 26 is also formed so as to have an upward inclination angle α.

As shown in FIG. 6, the ribs 26 for preventing falling off are formed in the same number as the ribs 21 for separating the wafer, but are slightly different from the corresponding wafers 21 for separating the wafer. It is formed at a low position, and a step d is secured between them.

As shown in FIG.
The frame-shaped body 15 formed on the back side of the rear wall is composed of two rear wall columns 31 and 32 erected in parallel, and horizontal plate parts 33 and 34 connecting the vertical wall columns 31 and 32 vertically. This back wall column 31,
32, a wafer separating rib 33 is formed at the same height as the wafer separating rib 21 formed on the side walls 13 and 14. Further, the rib 33 is formed so that the center portion swells as compared with both end portions. With these ribs 33, grooves 35 having the same pitch as the grooves 20 are formed in a line in the vertical direction. By providing such back wall columns 31 and 32, when the wafer W is inserted a predetermined distance from the opening 17, further entry is restricted.

The wafer cassette 10 of this embodiment is formed as described above, and its operation will be described below with reference to FIGS. Now, the wafer cassette 10 is used for transporting the wafer W,
After the wafer W is inserted by an automatic loading / unloading device or the like, the wafer W is placed on a transport belt and transported automatically. Diameter φ30
The semiconductor wafer W of FIG.
It is inserted on the left side of the figure through the vicinity of the center of the groove 20 between two adjacent ribs 21 from the side. At this time, the wafer W
Are inserted by an automatic insertion / removal device or the like so as to approach the back wall columns 31 and 32, that is, the frame 15, while being separated from the upper and lower wafer separation ribs 21. When the wafer W is inserted into the inside of the predetermined distance from the opening 17, the peripheral edge Wa of the front end of the wafer W approaches the rib 33 in FIG.
Here, the wafer W is separated from the loading / unloading device and moves downward by a small distance. Then, as shown by a two-dot chain line, the wafer W is held at two points on one side by the ribs 33 and 21. That is, both sides are held by a total of four ribs. At this time, even if the wafer W is slightly bent, it does not come into contact with the rib 26 for preventing falling off.

As described above, the peripheral portion of one wafer W is 4
In the state of being held by the two ribs 21 and 33, the contact area between the wafer W and the ribs is small, and since the ribs 21 and 33 are inclined inward and upward, the peripheral edge is particularly sharp. Even when the unprocessed wafers are stored, a large number of wafers W can be stored neatly in the vertical direction without cutting the wafer cassette.

Here, the cassette body 10 containing the wafer W is transported by a transport system such as a transport belt with the opening 17 in the horizontal direction, that is, in the horizontal direction. A relatively large vibration occurs due to a large speed change, and the front end Wa of the insertion side of the wafer W is
3 easily comes off. Alternatively, the rear end on the insertion side may partly protrude from the cassette body 16, but according to the present embodiment, the distal end peripheral edge Wa is provided with a rib 2 for preventing falling off.
6, the wafer W is prevented from falling down. Therefore, as shown in FIG. 9, it is possible to prevent the wafer W whose posture has been lost from colliding with another wafer W located below.

According to the present embodiment, the lower surface of the wafer W is always held in point contact by the four ribs, and the other portions are not in contact at all. There is nothing you can do.

When the wafer W is inserted in the horizontal direction, the peripheral edge Wa is guided by the groove 1 between the ribs 21, so that the wafer W is not inserted stepwise. In the above embodiment, the ribs 33 are formed one by one at the same height of the two back wall columns 31 and 32.
When three back wall pillars are provided, ribs may be provided for each of them, and may be formed as three ribs, or may not be formed on the center back wall pillar. Thus, the frame 1
The number of ribs provided in 5 is not limited to the embodiment.

[0027]

As described above, in the semiconductor wafer cassette according to the present invention, the lower surface of the wafer is held only by the wafer separating rib provided on the both side walls and the wafer separating rib provided on the back wall column. As a result, the contact area can be reduced.

Further, since ribs for preventing falling off are formed in addition to the ribs for separating the wafer, even if the front end of the wafer falls off from the two ribs for separating the wafer, the lowering rib is provided. Before it collides with one of the wafers, it comes into contact with a rib for preventing falling off and prevents the wafer from dropping further downward, so that other wafers are not damaged.

Further, the wafer separating ribs formed on both side walls of the cassette main body are formed with substantially arc-shaped steps which abut against the periphery of the semiconductor wafer and serve as stopper pieces. It can be prevented from jumping out of the cassette main body during the transportation.

The wafer separating ribs formed on both side walls of the cassette main body are formed so that the upper surface is bulged so that the lower surface of the semiconductor wafer is held in point contact with the wafer. The contact area with the unprocessed wafer can be reduced, and even if the unprocessed wafer is carried, even if the unprocessed wafer is conveyed, it is not cut off by the peripheral edge of the square unprocessed wafer. Can be prevented. Further, it is possible to prevent the semiconductor wafer from being rubbed and damaged during transportation.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a semiconductor wafer cassette according to an embodiment of the present invention with a top plate removed.

FIG. 2 is an enlarged cutaway perspective view showing a side wall portion of the semiconductor wafer cassette according to the embodiment.

FIG. 3 is a horizontal sectional view of a side wall shown in FIG. 2;

FIG. 4 is a longitudinal sectional view of a side wall portion shown in FIG. 2;

FIG. 5 is a longitudinal sectional view of another portion of the semiconductor wafer cassette shown in FIG. 1;

FIG. 6 is a front view of a side wall portion shown in FIG. 2;

7A is a front view of a back wall pillar of the semiconductor wafer cassette shown in FIG. 1, and FIG. 7B is a side view of the back wall pillar.

FIG. 8 is a perspective view when a wafer is actually inserted into the wafer cassette of the embodiment.

FIG. 9 is a side view showing a state where the leading end has dropped from a state where the wafer is inserted into the wafer cassette according to the embodiment.

FIG. 10 is a perspective view of a conventional wafer cassette.

FIG. 11 is a schematic view of a conventional automatic loading / unloading apparatus for inserting a wafer into a wafer cassette.

[Explanation of symbols]

 13, 14 Side wall 15 Frame-like body 16 Cassette body 17 Opening 20 Groove 21, 26 Wafer separating rib 22 Step 31, 32 Back wall post 33 Rib for preventing falling off

Claims (3)

[Claims] 1. A plurality of wafer separating means for forming a groove of a predetermined width in a vertical direction on an inner surface of both side walls of a cassette body having an opening for inserting a semiconductor wafer in a horizontal direction formed in a front part thereof. A semiconductor wafer cassette for transporting a semiconductor wafer housed horizontally in the groove from the opening, wherein the plurality of wafer separating ribs are formed on both side walls of the cassette body. A back wall column formed on each inner surface in a line in the vertical direction, and provided at a position where the peripheral edge of the front end of the semiconductor wafer opposed to the opening abuts to restrict further entry of the semiconductor wafer. A plurality of wafer separating ribs are formed in the vertical direction at a predetermined distance from each other, and between the wafer separating ribs on the both side walls and the wafer separating rib on the back wall column, Prescribed height low A rib for preventing falling off is formed so that a lower surface of the semiconductor wafer is held by a rib for separating the wafer formed on the both side walls and a rib for separating the wafer formed on the back wall column. When a part of the semiconductor wafer protrudes outward from the opening, the semiconductor wafer is held by the drop-off preventing ribs and the wafer separating ribs formed on the both side walls. A cassette for semiconductor wafers, characterized in that: 2. The wafer separating ribs formed on both side walls of the cassette main body are formed with substantially arc-shaped steps which abut against the periphery of the semiconductor wafer and serve as stopper pieces. The cassette for a semiconductor wafer according to claim 1. 3. The wafer separating ribs formed on both side walls and the back wall pillar of the cassette body are formed such that their upper surfaces are bulged so that the lower surfaces of the semiconductor wafers are held in point contact. The cassette for a semiconductor wafer according to claim 1, wherein the cassette is provided.