JPH06132390A - Wafer boat - Google Patents

Abstract

PURPOSE:To provide a wafer boat where wafers are mounted, wherein the rear side of the wafer can be protecte4 against reaction, and MOS semiconductor wafers can be enhanced in single-side processing efficiency. CONSTITUTION:Support shafts 4 provided upright surrounding the circumferences of wafers are provided, wafer holding cutouts 41 are provided to each of the support shafts 4, a wafer holding space V is formed inside the assembled support shafts 4, discs 5 of nearly the same shape as that of a water are provided in parallel with each other in a horizontal position to the support shafts 4 installed upright outside the wafer holding space V, the discs 5 are fixed so as to make a distance between the upsides of the discs equal to that between the centers of the cutouts 41, and furthermore the support shafts 4 and supports 3 are set relatively movable in a vertical direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer boat, and more specifically, it can prevent a reaction on the back surface of a wafer and can mount a plurality of wafers on one surface of a MOS semiconductor wafer or the like. The present invention relates to a novel wafer boat that can improve processing efficiency.

[0002]

2. Description of the Related Art In general, a so-called wafer boat is used in a processing apparatus which performs etching, assembling, CVD and the like on a large number of wafers in a batch process. Such a wafer boat is provided with notches for holding wafers on a plurality of support shafts erected so as to surround the peripheral edge of the wafer with a constant distance between the centers of the notches in the axial direction of the support shafts. A wafer holding space is formed inside the shaft. In the above-described wafer boat, for example, about 25 wafers can be loaded in the wafer holding space, both surfaces of each wafer can be exposed, and the wafers can be processed simultaneously, so that high processing efficiency can be obtained.

[0003]

By the way, in the processing of MOS semiconductor wafers and the like used for power devices, it is necessary to prevent the processing on the back surface of the wafer and perform the processing from one surface in order to stack circuits in more layers. is there. In the above-mentioned one-sided processing, usually, a holding device is used in which a wafer is placed on a base and processed one by one. In such a holding device, a high processing like that in the wafer boat is used. There is a problem that efficiency cannot be obtained. The present invention is
The present invention has been made in view of the above circumstances, and the purpose thereof is to be able to prevent the reaction on the back surface of a wafer, and to mount a plurality of wafers, and to improve the efficiency of single-sided processing of MOS semiconductor wafers and the like. To provide a novel wafer boat.

[0004]

In order to solve the above-mentioned problems, according to the present invention, a plurality of notches for holding a wafer are respectively provided on a plurality of support shafts erected so as to surround the periphery of the wafer. In a wafer boat in which a holding space for a wafer is formed inside these supporting shafts by providing a constant distance between the centers of the notches in the axial direction of the shaft,
A pillar is erected on the outside of the holding space, and a plurality of flat plates having substantially the same board surface shape as the wafer are aligned horizontally and in parallel on the pillar, and the distance between the upper surfaces of the flat plates is set between the centers of the notches. Is fixed at the same distance, and the flat plate is arranged concentrically with the space in the holding space, and the plurality of support shafts and the support columns are formed to be vertically movable relative to each other. I am trying. Further, in order to make the device structure compact, it is preferable that the support shaft is inserted into the column and an opening is formed in the column to expose the notch.

[0005]

In the wafer boat of the present invention, when the plurality of support shafts and the support columns are moved relative to each other in the vertical direction, the wafers held by the notches and the flat plates come into contact with each other so that the back surface of the wafer is covered with the flat plates. .

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view showing an embodiment of the wafer boat of the present invention, FIG. 2 is a horizontal sectional view of the wafer boat shown in FIG. 1, FIG. 3 is a sectional view taken along the line III-III in FIG. 2, and FIG. 5 is a partial side cross-sectional view showing a state during wafer loading by the wafer boat shown in FIG. 5, and FIG. 5 is a partial side cross-sectional view showing a state during wafer processing by the wafer boat shown in FIG.

The wafer boat shown in FIG. 1 is a wafer boat on which so-called circular wafers of, for example, 5 inches and 8 inches are mounted, and a plurality of support shafts (erected in a state of surrounding the periphery of the wafer ( 4) are provided with a plurality of notches (41) for holding wafers, each having a constant distance between the centers of the notches (41) in the axial direction of the support shaft (4). A wafer holding space (V) is formed in the wafer. In addition, the notch (4
The distance between the centers of 1) is shown by the code (L1) in FIG.

A column (3) is provided upright outside the holding space (V), and the column (3) further comprises:
A plurality of flat plates (5) having the same board shape as the wafer (5)
Are aligned horizontally and in parallel, and are fixed such that the distance between the upper surfaces of the flat plates (5) is the same as the distance between the centers of the notches (41). And the plurality of flat plates (5) are
The holding space (V) is arranged concentrically with the space, and the plurality of support shafts (4) and columns (3) are formed so as to be vertically movable relative to each other. The above flat plate (5)
The distance between the upper surfaces of is indicated by reference numeral (L2) in FIG.

Further, in this embodiment, in order to make the device structure compact, the support shaft (4) is inserted through the support column (3), and the notch (4) is formed in the support column (3).
An opening (31) for exposing 1) is opened.

The plurality of support shafts (4) are usually made of quartz and surround the periphery of the wafer, that is, as shown in FIG. 2, a virtual circle on which the wafer (6) is positioned. It is erected along the circumference of (R). Specifically, the support shaft (4) is provided at two positions that are symmetrical in the substantially diametrical direction on the virtual circle (R) and at two positions that are suitable for dividing the semi-circular arc portion having the diameter as a chord. It is placed in the place.

The notch (41) of the support shaft (4) is opened toward the center of the virtual circle (R). Notch (4
The notch depth of 1) is a depth until the diameter of the support shaft (4) is almost reached, as shown in FIG. Also, FIG.
And as shown in FIG. 5, the notch length of the notch (41) in the vertical direction is such that the edge of the wafer (6) mounted horizontally is somewhat loosely fitted to the wafer (6). Is formed to be slightly longer than the thickness of.

A plurality of the above-mentioned notches (41) are provided at the same position with respect to each support shaft (4), and the number thereof is the height of the reactor (not shown) into which the wafer boat is inserted. , And, depending on the number of wafers (6) to be processed, for example, they are provided at 25 to 50 places.

The arrangement of the plurality of notches (41) of each support shaft (4) is such that each notch (41) in the axial direction of the support shaft (4).
The distance (L1) between the centers of is constant. As shown in FIG. 4, the distance (L1) between the centers is equal to the thickness (height) of the robot arm (transport mechanism) (9) that supports the wafer (6) and moves back and forth in the horizontal direction. The thickness of the flat plate (5) attached to the outer surface of the column (3) is added at least.

Such notches (41) temporarily hold a plurality of wafers (6) loaded into or discharged from the wafer boat, whereby the plurality of support shafts (4) are supported. A wafer holding space (V) is formed inward.

The wafer boat of this embodiment, as shown in FIG. 1, is installed on a roof (1), a floor (2), and between the roof (1) and the floor (2) substantially vertically. An outer shell is composed of the pillars (3) formed. The top plate (1), the bottom plate (2), and the support columns (3) are usually made of quartz, and the top plate (1) and the bottom plate (2) are mounted as shown in FIG. It is formed in the shape of a circular flat plate having a diameter somewhat larger than that of the wafer (6).

The column (3) is provided to support the plurality of flat plates (5), is formed in a hollow pipe shape, and is erected at the same position as the support shaft (4). The support shaft (4) is inserted therethrough.

Further, as shown in FIG. 1, since the notches (41) of the support shaft (4) are exposed on each of the columns (3), a plurality of notches (41) are provided corresponding to the notches (41). An opening (31) is opened in each toward the center of the above-mentioned virtual circle (R). The depth of such an opening (31) is a depth up to about the diameter of the column (3). Further, the height of each opening (31) in the vertical direction is at least such that the robot arm (9) supporting the wafer (6) can advance and retract in the horizontal direction within the range of the height.

Further, as shown in FIGS. 2 and 3, the plurality of flat plates (5) fixedly mounted on the columns (3) each have a plate surface shape substantially the same as that of the wafer (6). The boards are arranged horizontally and in parallel. The arrangement of these flat plates (5) corresponds to the above-mentioned cutouts (41) and openings (31), and is fixed along the axial direction of each column (3) as shown in FIG. The distance (L2) between the upper surfaces of the flat plates (5) is the distance (L1) between the centers of the notches (41).
Is the same as. And each fixed flat plate (5)
Has its upper surface aligned with the bottom edge of the opening (31) orthogonal to the axis of the column (3).

Then, as shown in FIG. 1, the flat plate (5) has a wafer holding space (V) formed inside the support shaft (4) (support (3)). It is arranged concentrically with the space. That is, each opening (3) of the column (3) facing the center of the holding space (V).
In 1), the notches (41) of the inserted support shafts (4) are always exposed to each other.

Furthermore, in order to bring the above flat plates (5) into contact with the back surface of the wafer (6) during the processing of the wafer (6),
The support shaft (4) inserted through each of the columns (3) is the column (3).
It is formed so that it can be raised and lowered inside.

By the way, etching, ashing, CV
In a reactor of a batch type apparatus that performs processing such as D, a bottom lid (7) that opens and closes the reactor is formed to be movable up and down, and the wafer boat of the present embodiment is always mounted on this bottom lid (7). And then inserted into the reactor or taken out from the reactor. Therefore, the elevating mechanism of the support shaft (4) uses the above-mentioned bottom lid (7) and is configured as follows.

That is, as shown in FIG. 3, the support shaft (4) inserted through each of the columns (3) has its upper end penetrated by the roof (1) and its lower end by the bottom plate (2) and It is inserted into the bottom lid (7). And each support shaft (4)
Are connected to each other at their lower ends by a bar (11), and are configured to move up and down in synchronization by a driving means (8) such as a cylinder device provided on the bottom lid (7) side. Further, the end portion of each support shaft (4) of the portion protruding downward of the bottom lid (7) may be formed by another member made of a material other than quartz. The end of the support shaft (4) is covered with a bellows (10) in order to maintain airtightness in the reactor.

The wafer boat of the present embodiment constructed as described above is used as follows. [Wafer Loading Preparation] First, the bottom lid (7) of the reactor on which the wafer boat is mounted is lowered to take out the wafer boat from the reactor. Before the wafer (6) is loaded, the support shaft (4) inserted through each of the columns (3) is raised. In such a position, the support shaft (4)
Are provided with a plurality of notches (41) with a constant distance (L1) between the centers of the notches (41) in the axial direction of the support shaft (4), and the plurality of columns (3) are
Since the plurality of openings (31) are provided corresponding to the respective notches (41), the respective notches (41) are exposed above the inside of each opening (31).

[Wafer Loading] Next, as shown in FIG. 4, the wafer (6) to be processed is horizontally supported from the back surface by the suction portion (9c) of the robot arm (9), and the holding space ( Then, the wafer (6) is horizontally moved to fit in the notch (41) of the support shaft (4). Then, each time one wafer (6) is loaded, the above operation is repeated while the bottom lid (7) of the reactor is intermittently raised by the distance (L1) between the centers of the notches (41), For example, 25 wafers (6) are loaded in the holding space (V).

Support shaft (4) constituting the holding space (V)
The loaded wafer (6), as shown in FIG.
Since it is erected at four places so as to surround the substantially semicircular portion of the peripheral edge of the, the four notches (41) located in the same horizontal plane of each of these support shafts (4), as shown in FIG. The loaded wafer (6) is held at.

[Processing of Wafer] After the wafer (6) is loaded into the holding space (V), as shown in FIG. 5, the support shaft (4) is cut into the bottom surface (41e) of the notch (41) at the opening (3).
Position corresponding to the bottom edge of 1), that is, the corresponding flat plate (5)
Down to a position that matches the upper surface of. Then, the upper surface of the flat plate (5) contacts the back surface of the wafer (6), and the back surface of the wafer (6) held by the flat plate (5) and the bottom surface (41e) of the notch (41) is entirely covered.

Thus, in the state where the flat plate (5) is brought into contact with the back surfaces of the loaded wafers (6), the wafers (6) are horizontally and parallel to each other along the vertical direction. It is aligned and only the top surface of each wafer (6) is exposed. Therefore, in the reactor,
The reaction on the back surface of these wafers (6) can be prevented, and the processing such as etching, ashing, and CVD can be performed only from the upper surface. After loading the wafer (6) in the wafer boat, the operation of lowering the support shaft (3) to bring the back surface of the wafer (6) into contact with each flat plate (5) is performed before inserting the wafer boat into the reactor. It may be performed either during the insertion or after the insertion.

[Ejection of Wafer] Next, after the wafer (6) is subjected to the above-mentioned necessary treatment, the bottom lid (7) is lowered and the wafer boat is taken out of the reactor.
At this time, before, during or after lowering the bottom lid (7),
The drive means (8) provided on the bottom lid (7) side is actuated to raise each support shaft (4). As shown in FIG. 4, the raised position of the support shaft (4) is at least the notch (41).
Flat plate (5) corresponding to the bottom surface (41e) and notch (41)
The robot arm (9) supporting the wafer (6) forms a gap between the upper surface of the wafer and the upper surface of the wafer (6) so that the robot arm (9) can move back and forth.

As a result, the plurality of wafers (6) that were in contact with the flat plate (5) at the time of processing are simultaneously separated upward from the respective flat plates (5), and each wafer (6) and each flat plate ( A gap is formed between this and 5). Therefore, as in the case of loading, the robot arm (9) is inserted and the wafer (6) is inserted.
The wafer (6) which has been subjected to suction support and treated can be discharged from the wafer boat. When all the processed wafers (6) have been discharged, the wafer boat is ready to be loaded again for the next batch processing.

Thus, in this embodiment, for example, MO
When single-sided processing is performed on the wafer (6) such as S semiconductor, the reaction on the back surface can be prevented, and since a plurality of wafers (6) are processed simultaneously, high processing efficiency can be obtained. Then, the support shaft (4) is attached to the support column (3).
Since the opening (31) for exposing the notch (41) is opened in the support column (3), the device structure can be made compact.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 6 is a horizontal sectional view showing another embodiment of the present invention. In this embodiment, in the embodiment shown in FIG. 1, the column (3) and the support shaft (4) are erected in parallel.

That is, each support shaft (4) is provided separately from the support column (3) as a separate body. For example, the support shafts (3) are provided at three positions between the support columns (3) erected at four positions. 4) is erected. Similar to the embodiment shown in FIG. 1, the stanchions (3)
Is for forming an outer shell of the wafer boat and supporting a plurality of flat plates (5) at predetermined positions. In this case, the support columns (3) provided in the embodiment shown in FIG. The opening (31) is unnecessary. In addition, the support shafts (4) that make up the holding space (V), the flat plate (5) fixed to the columns (3), the roof (1) and the bottom plate (2), and the support shafts (4) are moved up and down. Each structure of the driving means (8) for
Is similar to the embodiment shown in FIG.

According to the wafer boat of this embodiment, the single-sided treatment of the wafer (6) can be efficiently performed, and the plurality of columns (3) and the support shaft (4) are erected in parallel. By installing the wafer boat, the structure of the wafer boat can be made simpler and the device cost can be reduced.

Next, still another embodiment of the present invention will be described. In this embodiment, a heating means is attached to each of the plurality of flat plates (5) in the embodiment shown in FIG. 1 or 6.

Although not shown, this heating means can use various types of heaters such as an embedded type sheath heater, a ceramic heater plate, and a film heater, and these heaters are provided inside a plurality of flat plates (5). It is embedded or attached to the back surface. Then, by a separately provided control means, preset electric power is supplied to maintain the temperature of each flat plate (5) at a predetermined temperature during processing. Furthermore, when the above heating means is attached,
In order to improve heat transfer efficiency, each flat plate (5) is preferably made of aluminum or an aluminum alloy.

Further, according to the wafer boat of this embodiment, the plurality of flat plates (5) abutting on the back surface of the wafer (6).
By attaching a heating means to each of them, the temperature distribution on the treated surface of each wafer (6) to be heated can be made uniform, and a homogeneous reaction can be obtained. Therefore, the wafer boat of this embodiment can be preferably used when ashing a wafer.

Next, still another embodiment of the present invention will be described. In this embodiment, cooling means is attached to each of the plurality of flat plates (5) in the embodiment shown in FIG. 1 or 6.

As the cooling means, although not shown, a cooling pipe through which low-temperature air, gas such as nitrogen, cooling water, or liquefied gas can be used. Such a cooling pipe is embedded inside the plurality of flat plates (5), or
It is arranged on the back side. Further, the cooling medium supplied to the cooling pipe is supplied at a preset flow rate by a separately provided control means, and each flat plate (5) is kept at a predetermined temperature while being prevented from rising in temperature during processing. Furthermore, when a cooling means is additionally provided, each flat plate (5) is preferably made of aluminum or an aluminum alloy in order to improve heat transfer efficiency, as in the previous embodiment.

According to the wafer boat of this embodiment, each flat plate (5) is provided with a cooling means to cool the resist provided on the surface of each wafer (6) during etching. It is possible to protect and obtain an etching pattern with high accuracy. Therefore, the wafer boat of this embodiment can be suitably used when etching a wafer.

Next, still another embodiment of the present invention will be described with reference to FIG. FIG. 7 is a horizontal sectional view showing another embodiment of the present invention. In the present embodiment, as shown in FIG. 7, in each of the above-described embodiments, the plurality of flat plates (5) are formed in a rectangular plate shape.

The support pillars (3) to which the plurality of flat plates (5) are fixed and the support shafts (4) inserted into the support pillars (3) are, for example, on the short side of the flat plate (5). 1 for each
It is erected in two places on one side of the long side. In addition, a top plate (1) and a bottom plate (2) that form the outer shell of the wafer boat.
Has a rectangular planar shape, like the flat plate (5). Others, support (3), support shaft (4), bottom lid (7)
The drive means (8) and the like provided in the above are configured in the same manner as in the embodiment shown in FIG.

According to the embodiment shown in FIG. 7, by making the plate surface shape of the plurality of flat plates (5) rectangular, it is possible to simultaneously perform the one-side processing on the plurality of rectangular wafers (6), Similar to the circular wafer (6) illustrated in each of the above-described embodiments, the processing efficiency can be improved.
Moreover, since the support shaft (4) is inserted through the support column (3), the wafer boat can be made compact. Therefore, it can be suitably used in the processing of a rectangular wafer (6) used for an LCD substrate or the like.

FIG. 8 is a horizontal sectional view showing still another embodiment of the present invention. This embodiment is similar to the embodiment shown in FIG. 7, and in each of the above-mentioned embodiments, the plurality of flat plates (5) are formed so that the board surface shape thereof is square, and the pillars (3) are The support shaft (4) is erected in parallel. Further, in the case of the present embodiment, from the viewpoint of the support strength of the flat plate (5), for example, the pillar (3) may have a rectangular cross section.

According to the embodiment shown in FIG. 8, as in the embodiment shown in FIG. 7, by making the plate surface shape of the plurality of flat plates (5) square, a rectangular wafer used for an LCD substrate or the like. It is possible to perform the one-sided processing simultaneously for the plurality of (6), and it is possible to improve the processing efficiency. Moreover, by vertically arranging the support column (3) and the support shaft (4) in parallel, the device configuration can be simplified and the device cost can be reduced.

Even when a plurality of flat plates (5) are formed in a rectangular shape as in the embodiment shown in FIG. 7 or FIG. 8, each flat plate (5) is provided with the above-mentioned heating means, Alternatively, by providing a cooling means, it can be suitably used for ashing or etching on a square wafer.

Further, as shown in each of the above-described embodiments, the wafer boat of the present invention has no mechanical part to be inserted into the reactor, and the inserting part into the reactor is mainly made of quartz. Therefore, the problem of deterioration due to high temperature treatment does not occur. Moreover, the wafer boat of the present invention can have a simple device configuration without complicated links of mechanical elements.

In each of the above-mentioned embodiments, the support shaft (4) side for holding the plurality of wafers (6) is formed to be movable up and down, but by moving the support (3) side up and down, a plurality of flat plates (5) are formed. ) May be formed to be movable up and down. Further, each notch (41) of the support shaft (4) may substantially hold the wafer (6) in the holding space (V), and the opening in the axial direction becomes closer to the axis of the support shaft (4). It may be formed in a recess having a reduced height, for example, a V-shaped cross section.

[0048]

As described above, according to the wafer boat of the present invention, it is possible to prevent the reaction on the back surface of the wafer and to mount a plurality of wafers.
It is possible to improve processing efficiency in single-sided processing of OS semiconductor wafers and the like. Further, if each support shaft is inserted into the support column, the device configuration can be made compact.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a wafer boat of the present invention.

FIG. 2 is a horizontal sectional view of the wafer boat shown in FIG.

3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a partial side cross-sectional view showing a state when wafers are loaded by the wafer boat shown in FIG.

5 is a partial side sectional view showing a state during wafer processing by the wafer boat shown in FIG. 1. FIG.

FIG. 6 is a horizontal sectional view showing another embodiment of the present invention.

FIG. 7 is a horizontal sectional view showing another embodiment of the present invention.

FIG. 8 is a horizontal sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 1 Top Plate 2 Bottom Plate 3 Support 31 Opening 4 Support Shaft 41 Notch 41e Notch Bottom 5 Flat Plate 6 Wafer 7 Reactor Bottom Cover 8 Drive Means 9 Robot Arm (Transfer Mechanism) 9c Adsorption Part 10 Bellows 11 Bar V Wafer Holding Space L1 Distance between centers of plural notches L2 Distance between upper surfaces of plural flat plates

Claims (2)

[Claims] 1. A plurality of notches for holding a wafer are respectively provided on a plurality of support shafts erected so as to surround a peripheral edge of a wafer with a constant distance between centers of the notches in the axial direction of the support shaft. In a wafer boat in which a holding space for wafers is formed inside these support shafts, a support pillar is provided upright outside the holding space, and a plurality of flat plates having substantially the same board surface shape as the wafer are horizontally installed on the support pillar. And are arranged in parallel and fixed so that the distance between the upper surfaces of the flat plates is the same as the distance between the centers of the notches, and the flat plates are arranged concentrically with the space in the holding space, and A wafer boat, characterized in that the support shaft and the support column are formed so as to be relatively movable in the vertical direction. 2. The wafer boat according to claim 1, wherein the support shaft is inserted into the column, and the column is provided with an opening for exposing the notch.