KR20050090140A - Cassette for storing a plurality of semiconductor wafers - Google Patents

Abstract

A cassette for storing multiple sheets of semiconductor wafers at intervals in vertical direction, comprising multiple sheets of support plates disposed at intervals in vertical direction and partition plates disposed between the support plates, wherein receiving cutouts formed so as to match the shape of a suction device for suckingly holding the semiconductor wafers are formed in the front half parts of the support plates.

Description

CASSETTE FOR STORING A PLURALITY OF SEMICONDUCTOR WAFERS

The present invention relates to a cassette for accommodating a plurality of semiconductor wafers at intervals in the vertical direction.

As is well known to those skilled in the art, when grinding or cutting a semiconductor wafer, several semiconductor wafers are accommodated in a cassette and the cassette is sent to a desired place. The cassette has a pair of sidewalls extending vertically at intervals in the width direction, and a support protrusion or support groove is formed on the inner surface of the sidewall at intervals in the vertical direction. Each semiconductor wafer is received into the cassette by placing both edges thereof on the corresponding support protrusions of the two side walls or in the support grooves, respectively. Therefore, in the cassette, a plurality of semiconductor wafers are accommodated at intervals in the vertical direction (these intervals correspond to the gap between the support protrusion or the support groove). An adsorption port having a suction hole on the upper surface is used for loading and unloading the semiconductor wafer into and out of the cassette. When the semiconductor wafer is brought into the cassette, the vacuum wafer is vacuum-adsorbed onto the suction hole and brought into the desired position in the cassette, and then the vacuum suction of the semiconductor wafer is released to leave the semiconductor wafer in the cassette, and the suction hole is pulled out of the cassette. When the semiconductor wafer is taken out from the cassette, an adsorption port is inserted into the cassette and placed under the semiconductor wafer, the semiconductor wafer is vacuum-adsorbed onto the adsorption port, and then the adsorption port adsorbing the semiconductor wafer is removed from the cassette. .

By the way, the above conventional cassette had the following problems. In other words, semiconductor wafers are made very thin in recent years. For example, when the thickness is less than 100 μm, in particular 50 μm or less, it is rare that when a semiconductor wafer with a significantly thin thickness is accommodated in a cassette, the semiconductor wafer tends to be concave and be displaced downward. . It is not necessarily constant that each semiconductor wafer is bent, and therefore, when the semiconductor wafer is bent, the vertical gap between several semiconductor wafers housed in the cassette at intervals in the vertical direction becomes very narrow locally. For this reason, when an adsorption port is inserted in a cassette and positioned below a semiconductor wafer, there exists a possibility that an adsorption hole may collide with a semiconductor wafer and damage a semiconductor wafer. In addition, when the semiconductor wafer is warped a lot, two semiconductor wafers located adjacent to each other in the vertical direction may come into contact with each other, which may damage the semiconductor wafer.

Japanese Laid-Open Patent Publication No. 2000-91400 discloses a cassette in which a plurality of support plates are provided in the cassette at intervals in the vertical direction at intervals to form a receiving space for several semiconductor wafers in the cassette. Each support plate is provided with cutouts corresponding to the shape of the suction holes for suction-holding the semiconductor wafer. In such a cassette, each semiconductor wafer is supported not only at both edge portions, but also at its central portion, and curvature due to its own weight of the semiconductor wafer is suppressed. In addition, since the semiconductor wafers adjacent in the vertical direction are isolated by the supporting plate, the two semiconductor wafers adjacent in the vertical direction are not in contact with each other.

However, the cassette disclosed in Japanese Patent Laid-Open No. 2000-91400 is not yet satisfactory enough. According to the experience of the present inventors, by grinding the back surface, the semiconductor wafer which is significantly thinned is curved into a concave or convex shape due to grinding skew or crystal orientation. Therefore, even when the semiconductor wafer is supported not only at both edges thereof, but also at the center thereof, the semiconductor wafer is curved. Therefore, even when using the cassette disclosed in Japanese Patent Laid-Open No. 2000-91400, there is still a risk of damaging the semiconductor wafer by colliding the adsorption port with the semiconductor wafer when inserting the adsorption port into the cassette.

1 is a perspective view of a cassette constructed in accordance with the present invention.

FIG. 2 is a front view of the cassette of FIG. 1. FIG.

3 is a perspective view illustrating a support plate in the cassette of FIG. 1.

4 is a perspective view illustrating a separator in the cassette of FIG. 1.

FIG. 5 is a cross-sectional view showing the side wall and the rear member in the cassette of FIG. 1. FIG.

6 is a perspective view illustrating a typical example of a semiconductor wafer transport means.

FIG. 7 is a cross-sectional view illustrating an example of a method of loading a semiconductor wafer into the cassette of FIG. 1.

8 is a cross-sectional view illustrating an example of a method of carrying out a semiconductor wafer from the cassette of FIG. 1.

Therefore, the object of the present invention is sufficiently sure that even when the semiconductor wafer is curved into a concave shape or a convex shape, the suction port collides with the semiconductor wafer and the semiconductor wafer is damaged when the semiconductor wafer is brought in or taken out of the cassette. To provide new and improved cassettes.

According to the present invention, in order to achieve the above object, while installing a plurality of support plates at intervals in the vertical direction, a separator plate is provided between each support plate.

That is, according to the present invention, a cassette for achieving the above object is provided with a plurality of support plates provided at intervals in the vertical direction, and the shape corresponding to the shape of the adsorption port for adsorbing and holding the semiconductor wafer in the first half of each support plate. As a cassette for accommodating a plurality of semiconductor wafers at intervals in the up and down direction, in which the notch is formed,

A cassette is provided between the supporting plates, wherein a separator is provided.

Each of the separators is preferably formed of a plate having a shape corresponding to that of the semiconductor wafer. It is preferable that the ceiling plate is installed above the support plate located at the top, and the bottom plate is installed below the support plate located at the bottom.

Hereinafter, with reference to the accompanying drawings showing a preferred embodiment of a cassette constructed in accordance with the present invention will be described in more detail.

1 and 2, a cassette, which is denoted by the reference numeral 2 for the entire structure according to the present invention, includes a ceiling plate 4 and a bottom plate 6. As shown in FIG. The ceiling plate 4 is substantially disk-shaped and has bow-shaped protrusions 8 on both sides. Similarly, the bottom plate 6 is also substantially disk-shaped and has bow-shaped protrusions 10 on both sides. A vertically extending side wall 12 is fixed between the protrusion 8 of the ceiling plate 4 and the protrusion 10 of the bottom plate 6. On the rear edges of the ceiling plate 4 and the bottom plate 6, a pair of rear members 14 extending vertically at intervals are fixed. On the upper side of the protrusion part 8 of the ceiling plate 4, the handle member 16 which has a channel shape of a horizontal cross section is fixed. When carrying the cassette 2 manually or by a suitable conveying means (not shown), the handle member 16 can be used.

Between the ceiling plate 4 and the bottom plate 6, the support plate 18 of several sheets (five pieces in the figure) is provided at predetermined intervals in the up-down direction. And the separator 20 is provided between each support plate 18. 3 and 5 together with FIGS. 1 and 2, a plurality of support protrusions 22 (nine in the figure) are disposed on the inner surface of the side wall 12 at predetermined intervals in the vertical direction. Formed. Similarly, several support protrusions 24 (nine in the figure) are formed on the inner surface of the rear member 14 at predetermined intervals in the vertical direction. The support plates 18 are arranged at predetermined positions by counting their perimeters from above and fixing them on the odd-numbered protrusions 22 and 24, and the separator plate 20 counts their perimeters from above and the even-numbered protrusions ( It is arrange | positioned at the predetermined position by fixing on 22 and 24). As clearly shown in Fig. 3, each of the supporting plates 18 is substantially semi-circular, and both sides thereof have a straight line along the inner surface of the side wall 12, and the first half has a shape corresponding to the shape of the adsorption portion described later. Acceptance notch 26 of is formed. As shown in FIG. 4, each separator 20 is substantially disk-shaped substantially corresponding to the shape of a semiconductor wafer, and the both sides are linear form along the inner surface of the side wall 12. As shown in FIG.

The cassette 2 as described above has its components (ie, ceiling plate 4, bottom plate 6, side wall 12, rear member 14, handle member 16, support plate 18 and isolation). The plate 20 can be preferably formed by forming a synthetic resin or a metal thin plate, and connecting such components by appropriate means such as bonding.

FIG. 6 shows a typical example of the semiconductor wafer conveying means 28 used to import or unload a semiconductor wafer to and from the cassette 2. The semiconductor wafer conveying means 28 shown by itself is a well-known form, and is mounted so that it can pivot freely to the upper and lower sides of the lifting shaft 32 and the lifting shaft 32 mounted to the support 30 so that it can lift freely. The first pivot arm 34, the second pivot arm 36 mounted freely at the tip of the first pivot arm 34, and the mounting block 38 fixed to the tip of the second pivot arm 36. ) And a suction port 42 mounted to the mounting block 38 so as to rotate freely about the central axis 40 extending substantially horizontally. The illustrated suction port 42 has a fork shape having two blades, and a porous suction piece 46 is provided on the suction surfaces (upper surface in FIG. 6) of the two blades 44. If desired, other suitable types of suction holes may be used, and it is important that the shape of the receiving notches 26 in the support plate 18 correspond to the shape of the suction holes used. Although not shown in the semiconductor wafer carrying means 28, the lifting means for lifting and lowering the lifting shaft 32, the first turning means for turning the first pivot arm 34, and the second pivot arm are pivoting. The second turning means and the rotating means for rotating the suction port 42 is provided. Furthermore, suction means for selectively connecting the suction piece 46 of the suction port 42 to the vacuum source is also provided.

The semiconductor wafer 48 is substantially disk-shaped, and has a straight edge 50 at its periphery called an orientation plate. When transporting the semiconductor wafer 48 by the semiconductor wafer transport means 28, the suction surface of the suction port 42 is brought into close contact with one surface of the semiconductor wafer 48 to connect the suction piece 46 to a vacuum source. In this way, the semiconductor wafer 48 is attracted to the adsorption port 42.

For example, when removing the semiconductor wafer 48 whose back surface was ground from above the chuck means (not shown) of a grinding machine, the suction port 42 of the semiconductor wafer conveyance means 28 is shown in FIG. It rotates 180 degree in the state, so that the adsorption surface in which the adsorption piece 46 is provided may face downward. Then, the suction surface of the suction port 42 is pressed against the back surface exposed above the semiconductor wafer 48 on the chuck means, and the semiconductor wafer 48 is sucked onto the suction surface. FIG. 7 shows an example of a method in which the semiconductor wafer 48 adsorbed to the adsorption port 42 is carried on the support plate 18 positioned on the top of the cassette 2. When bringing the semiconductor wafer 48 into the cassette 2, the semiconductor wafer 48 is adsorbed on the adsorption surface of the adsorption port 42, removed from the chuck means, and then the adsorption port 42 is rotated 180 degrees. The suction surface adsorbing the wafer 48 is directed upward. Then, as shown in FIG. 7A, the two blades 44 of the suction port 42 correspond to the storage notches 26 of the support plate 18, and the semiconductor wafer 48 is placed above the support plate 18. A semiconductor wafer 48 adsorbed on the adsorption port 42 and its adsorption surface is inserted into the cassette 2 by positioning. Next, the adsorption | suction of the semiconductor wafer 48 is stopped by blocking the adsorption | suction piece 46 of the adsorption port 42 from a vacuum source, and opening it to air | atmosphere. Then, the suction port 42 is lowered. When the suction port 42 descends to the position shown in FIG. 7B, the semiconductor wafer 48 is placed on the support plate 18. When the adsorption of the semiconductor wafer 48 by the adsorption piece 46 is stopped, when the semiconductor wafer 48 is remarkably thin, due to grinding skew or crystal orientation, it is concave, for example, as shown in FIG. 7B. Tends to bend (or vice versa). Subsequently, as shown in FIG. 7C, the adsorption port 42 is slightly lowered again to completely remove the adsorption port 42 from the semiconductor wafer 48 placed on the support plate 18. Then, the suction port 42 is pulled out of the cassette 2. The carrying-in of the semiconductor wafer 48 on the support plate 18 other than the top support plate 18 can also be performed similarly.

8 shows an example of a method of carrying out the semiconductor wafer 48 placed on the uppermost support plate 18 from the cassette 2. First, as shown in FIG. 8A, the suction port 42 is inserted between the uppermost support plate 18 and the separator 20 positioned below it with the suction surface facing upward. Next, as shown to FIG. 8B and FIG. 8C, the suction port 42 is raised through the accommodation notch 26 of the support plate 18. FIG. When the suction port 42 is raised to the position shown in FIG. 8C, the semiconductor wafer 48 is pressed against the inner surface of the ceiling plate 4 (in the case of the semiconductor wafer 8 located below, above the support plate 18). The curvature of the semiconductor wafer 48 is correct | amended by pressing on the inner surface of the separator 20 located, and the semiconductor wafer 48 will be in a flat state. Then, the suction piece 46 of the suction port 42 is connected to the vacuum source to suck the semiconductor wafer 48 onto the suction surface. Subsequently, the adsorption port 42 is slightly lowered to drop the semiconductor wafer 48 from the inner surface of the ceiling plate 4 (or the separator 20), and then the adsorption port 42 which adsorbs the semiconductor wafer 48 thereafter. ) Is removed from the cassette (2).

In the embodiment shown in FIG. 7 and FIG. 8, the adsorption port 42 which adsorbs the semiconductor wafer 48 is inserted into the cassette 2 with the adsorption surface facing upward, and the support plate 18 of the cassette 2 is inserted. ), And also when carrying out the semiconductor wafer 48 on the support plate 18 on the support plate 18, the adsorption port 42 is placed in the cassette (with the adsorption surface facing upward). 2) It is inserted in. However, if desired, the adsorption port 42 on which the semiconductor wafer 48 is adsorbed is in the state in which the adsorption surface faces downward, and thus the adsorption port is adsorbed on the lower surface of the adsorption port 42. The 42 may be inserted into the cassette 2 and placed on the separator 20 positioned below the support plate 18 but not below it. In this case, when carrying out the semiconductor wafer 48 on the separator 20 from the cassette 2, the suction port 42 may be inserted into the cassette 2 with the suction surface facing downward. .

As mentioned above, although the preferred embodiment of the cassette constructed according to the present invention was described in detail with reference to the accompanying drawings, this invention is not limited to this embodiment, It can be variously modified or modified without departing from the scope of the present invention.

Claims (3)

A plurality of semiconductor wafers are provided with a plurality of support plates spaced apart in the vertical direction, and the first and second portions of the support plates are provided with receiving cutouts in a shape corresponding to the shape of the suction holes for adsorbing and holding the semiconductor wafer. As a cassette for accommodating at intervals, A cassette, characterized in that a separator is provided between each of the supporting plates. The method of claim 1, And each separator is formed of a plate having a shape approximately corresponding to that of a semiconductor wafer. The method of claim 1, The cassette is installed at the top of the support plate located at the top and the bottom plate is installed at the bottom of the support plate at the bottom.