JPH08107079A - Vertical wafer boat and vertical heat treatment furnace - Google Patents

Abstract

PURPOSE: To provide a vertical heat treatment furnace by which the slippage defect of a semiconductor wafer can be avoided by a method wherein the top ends of water support members are hung on the top support plate of an outer frame so as to be attached/detached freely. CONSTITUTION: A semiconductor wafer boat 1 is composed of a plurality of semiconductor wafer support members 2 on which a plurality of semiconductor wafer insertion grooves 2a are respectively formed at certain intervals in a longitudinal direction and an outer frame 3 on which the semiconductor wafer support members 2 are hung so as to be attached/detached freely. On the other hand, a plurality of retaining holes 7 from which the semiconductor wafer support members 2 are hung are bored in the circumferential part of a top support plate 4 which is a component of the outer frame 3. The top parts of a plurality of the semiconductor wafer support member 2 are inserted respectively into the retaining holes 7 from below inside the top support plate 4 and notched recesses 2b which are formed on the top parts of the semiconductor wafer support members 2 are retained with the edges of the retaining holes 7 to be hung.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical wafer boat and a vertical heat treatment furnace, and more specifically to a vertical heat treatment furnace for treating a plurality of semiconductor wafers in a manufacturing process for heat treating semiconductor wafers. The present invention relates to a wafer boat and its vertical heat treatment furnace.

[0002]

2. Description of the Related Art Generally, in order to manufacture a semiconductor wafer, many heat treatment steps are required for oxidation / diffusion, precipitation, etc. The heat treatment of a semiconductor wafer having a diameter of up to 6 inches is mainly a horizontal heat treatment. Furnaces have been used. However, with the increase in diameter of semiconductor wafers, the total weight of semiconductor wafers to be heat-treated increases, and the wafer boat may become unusable due to thermal deformation.
In recent years, vertical heat treatment furnaces have been widely used. Further, in this vertical heat treatment furnace, a vertical wafer boat for loading a plurality of semiconductor semiconductor wafers in the vertical direction is used.

The vertical wafer boat used in the vertical heat treatment furnace has a predetermined interval in the longitudinal direction as disclosed in, for example, JP-A-60-107843 and JP-A-3-295227. A plurality of semiconductor wafer insertion grooves are formed, and the semiconductor wafer supporting member is vertically arranged around the semiconductor wafer, and a supporting plate for fixing the upper and lower ends of the semiconductor wafer supporting member.

In the vertical type semiconductor wafer boat, the so-called assembling type wafer boat in which each member of the semiconductor wafer supporting member and the supporting plate is manufactured and assembled, and the semiconductor wafer supporting member and the supporting plate are welded or adhered to each other. There is a so-called integrated wafer boat that is integrally formed. From the viewpoint of welding or adhering each member, a material such as a SiC-based material having excellent welding or adhesiveness, quartz glass, or the like is used for the integrated wafer boat, while an assembled wafer boat has a high-purity quartz glass or A silicon material is used.

As described above, in the integrated type wafer boat and the assembled type wafer boat made of a predetermined material, a plurality of semiconductor wafers are vertically loaded and housed in a vertical heat treatment furnace, and the semiconductor wafers are set in a predetermined manner. Is heat treated.

[0006]

During this heat treatment, in order to perform the desired heat treatment on all the semiconductor wafers housed in the vertical heat treatment furnace, the heat treatment temperature in the vertical heat treatment furnace must be set. It is necessary to make it uniform. However, although various measures have been taken for the vertical heat treatment furnace, the range in which the heat treatment temperature is uniform is limited to a certain range of the vertical heat treatment furnace. Specifically, the temperature of the heat-retaining cylinder and its adjacent portion (the lower end portion of the vertical heat treatment furnace) are lower than those of other portions of the vertical heat treatment furnace (the upper end portion and the intermediate portion of the vertical heat treatment furnace). .

On the other hand, even with an assembled wafer boat,
Even in the integrated wafer boat, the semiconductor wafer supporting member and the lower end portion of the semiconductor wafer boat holding the semiconductor wafer supporting member have a thermally integrated structure, and the vertical wafer boat is mounted on the heat insulating cylinder. Therefore, the temperature of the lower portion of the semiconductor wafer boat supporting member may be lower than that of other portions. Further, since the semiconductor wafer is stored up to the lower end of the semiconductor wafer supporting member, it may be out of the soaking region of the vertical heat treatment furnace.

As a result, a local temperature distribution varies in the semiconductor wafer located in the lower part of the furnace having a low temperature, which causes a slip defect in the semiconductor wafer. was there.

Further, in the case of an integrated type semiconductor wafer boat, the semiconductor wafer boat set may become unusable if a part of the semiconductor wafer insertion groove is missing, and it is necessary to make it an integral type by welding or bonding. However, there is a technical problem that it is difficult to use a silicon material excellent in purity. On the other hand, the assembly type semiconductor wafer boat can use a silicon material having excellent purity, but since it is not an integral structure, it is weak in strength and may cause damage to the boat itself. Also, since there is a slight gap in the assembly part, there is rattling and
There was a problem that a tickle was generated.

The present invention has been made in order to solve the above-mentioned conventional technical problems, and includes a semiconductor wafer supporting member for supporting a plurality of semiconductor wafers and an outer frame for detachably suspending the semiconductor wafer supporting member. And the vertical semiconductor wafer boat capable of thermally separating the components and using the optimum material for each constituent member, and improving the quality of the semiconductor wafer, and variations in local temperature distribution in the semiconductor wafer. It is an object of the present invention to provide a vertical heat treatment furnace which does not cause a slip defect in a semiconductor wafer without causing a crack.

[0011]

In order to achieve such an object, a vertical semiconductor wafer boat according to the present invention comprises:
An outer frame composed of a plurality of columns and at least an upper support plate integrally fixed to the upper end portion of the column or detachably assembled, and at a predetermined interval in the longitudinal direction,
A plurality of wafer supporting members having a plurality of wafer insertion grooves are formed, and an upper end portion of the wafer supporting members is detachably hung on an upper supporting plate of an outer frame. Also, an outer frame composed of a plurality of columns, an upper support plate and a lower upper support plate integrally fixed to the upper and lower ends of the columns or detachably assembled, and a plurality of frames at a predetermined interval in the longitudinal direction. And a plurality of wafer supporting members each having a wafer insertion groove formed therein, and an upper end portion of the wafer supporting members is detachably suspended from an upper supporting plate of an outer frame. Further, an outer frame composed of the plurality of columns and at least the upper support plate has a configuration made of any one material of Si-impregnated SiC, CVD-SiC coated Si-impregnated SiC, or quartz glass, The wafer support member is silicon, CVD-SiC coated Si-impregnated Si
It has a structure made of any one of C and quartz glass.

Further, in a vertical heat treatment furnace having a furnace core tube, a heating body on the outside thereof, and the vertical wafer boat, when the wafer boat is housed in the furnace core tube, an upper support plate of the wafer boat outer frame is provided. It has a configuration in which the suspended lower end of the wafer supporting member is arranged so as to be located within a range of a soaking region in the furnace core tube.

[0013]

In the vertical wafer boat according to the present invention, a plurality of semiconductor wafer support members having a plurality of semiconductor wafer insertion grooves formed at predetermined intervals in the longitudinal direction and an upper end portion of the semiconductor wafer support member are detachable. It is composed of an outer frame to be hung, and when a semiconductor wafer supporting member loaded with a plurality of semiconductor wafers is hung on the inner upper part of the outer frame,
Since the lower end of the semiconductor wafer supporting member and the lower end of the semiconductor wafer boat of the outer frame are thermally separated, even if the vertical semiconductor wafer boat is placed on the heat insulating cylinder, the lower end of the semiconductor wafer supporting member The temperature never goes down.
Further, when the wafer boat is housed in a furnace core tube of a vertical heat treatment furnace, the lower end portion of the wafer support member hung on the upper support plate of the wafer boat outer frame is a soaking region in the furnace core tube. It was arranged so as to be located within the range. As a result, it is possible to prevent the occurrence of local temperature distribution variations in the semiconductor wafer due to the heat treatment, and to reduce the occurrence of slip defects.

Further, since the outer frame does not require processing such as a semiconductor wafer insertion groove, Si-impregnated SiC, CVD-SiC
The integrated structure can be made of a material having high strength and high heat resistance such as coated Si-impregnated SiC and quartz glass, and the semiconductor wafer supporting member is subjected to a tensile force by being hung on an outer frame. Since it is a simple shape and easy to process, it is a relatively high purity silicon, CV
Even if a material such as Si-impregnated SiC coated with D-SiC or quartz glass is used, it can be manufactured at low cost, and even if it is used at a relatively high temperature, it does not cause boat deformation after heat treatment.

Therefore, according to the present invention, it is possible to manufacture a semiconductor wafer boat which has high mechanical strength, is easy to process, and is inexpensive, and improves the quality of semiconductor wafer products obtained by heat treatment.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of a vertical semiconductor wafer boat accommodated for a vertical heat treatment furnace according to the present invention,
2 is a perspective view showing a state in which a plurality of semiconductor wafers are loaded on the semiconductor wafer boat of FIG. 1, FIG. 3 is a view showing another embodiment of the vertical type semiconductor wafer boat, and FIG. 4 is the semiconductor wafer boat of FIG. It is a figure which shows the cross section of the vertical heat treatment furnace which accommodates.

As shown in the figure, the semiconductor wafer boat 1
Is a plurality of semiconductor wafer supporting members 2 having a plurality of semiconductor wafer insertion grooves 2a formed at predetermined intervals in the longitudinal direction, and an outer frame 3 on which the semiconductor wafer supporting members 2 are detachably suspended. It is composed by.

Here, the semiconductor wafer support member 2 is made of silicon or Si-impregnated Si coated with CVD-SiC.
It is a rod-shaped body formed of a material such as C or quartz glass, and has a plurality of semiconductor wafer insertion grooves 2a formed at predetermined intervals in the longitudinal direction and the upper end portion of the semiconductor wafer support member 2 A U-shaped cutout concave portion 2b is formed in the.

The sectional shape of these semiconductor wafer supporting members 2 is preferably a shape that does not rotate when the semiconductor wafer supporting member 2 is assembled. The sectional shape may be circular, but positioning is not necessary. Since it is troublesome, it is usually preferable to use a shape such as an ellipse, an ellipse, a rectangle, or a square. Since the semiconductor wafer supporting member is not welded or adhered, a high-purity silicon material can be used. Moreover, since only the tensile force acts by suspending it on the outer frame, even if a high-purity silicon material or quartz glass is used, no deformation occurs after heat treatment.

Here, the silicon material means single crystal silicon or polycrystalline silicon.

The outer frame 3 is composed of an upper support plate 4, a lower support plate 5, and a plurality of columns 6, and the upper support plate 4 and the lower support plate 5 are on one side of the semiconductor wafer insertion side. It is integrally fixed to the upper and lower ends of the columns 6 arranged at equal intervals on a semicircular portion (corresponding to 180 degrees) except for half. Here, since the outer frame 3 is made of a material such as Si-impregnated SiC, CVD-SiC-coated Si-impregnated SiC, or quartz glass, the upper support plate 4 and the lower support plate 5 are the upper and lower end portions of the column 6. It can be fixed by welding or adhesion, but can also be detachably assembled. However, in consideration of the strength of the outer frame 3 and the generation of particles from the outer frame structural member, it is preferable to fix them by welding or adhesion.

On the other hand, a plurality of engaging holes 7 for suspending the semiconductor wafer supporting member 2 are formed in the circumference of the upper supporting plate 4 which constitutes the outer frame 3, and the upper part of the engaging holes 7 is formed. Notch recesses 2b formed in the upper ends of the semiconductor wafer support members 2 by inserting the upper ends of the plurality of semiconductor wafer support members 2 from the inner lower surface of the support plate 4 respectively.
Can be engaged with the edge portion of the engagement hole 7 and can be suspended.

At this time, the notch recess 2b is formed in the engaging hole 7
Even if the semiconductor wafer supporting member 2 is engaged with the edge portion of the semiconductor wafer supporting member 2, the semiconductor wafer supporting member 2 may fall off the upper supporting plate 4 due to a difference in thermal expansion. In order to prevent this, after the notch recess 2b is engaged with the edge of the engagement hole 7, the gap formed by the engagement hole 7 and the surface opposite to the notch recess formation surface of the semiconductor wafer supporting member 2 is separated. -It is preferable that a notch (not shown) is inserted to make it difficult for the notch recess 2b to separate from the edge of the engagement hole 7.

Further, a plurality of semiconductor wafer supporting members 2 suspended in the engaging holes 7 of the upper supporting plate 4 are provided with a plurality of semiconductor wafer supporting members 2 via the semiconductor wafer insertion grooves 2a formed in each semiconductor wafer supporting member 2. Semiconductor semiconductor wafers 8 are vertically stacked in a horizontal state. When the semiconductor wafer support members 2 are suspended from the upper support plate 4 of the outer frame 3, the lower end portions of the semiconductor wafer support members 2 are suspended. Is formed at a height h that does not contact the lower support plate 5 of the outer frame 3.

That is, the height h of the semiconductor wafer supporting member 2 is set in the vertical heat treatment furnace with the outer frame 3 loaded with the semiconductor wafers 8 set inside a predetermined vertical heat treatment furnace (not shown). Since it is set within the range of the soaking region (the lower end portion of the semiconductor wafer supporting member 2 is not extended to the lower portion of the vertical heat treatment furnace having a low temperature),
Almost uniform heat acts on all the semiconductor wafers 8 during the heat treatment.

Further, since the semiconductor wafer supporting member 2 is formed at the height h which does not contact the lower supporting plate 5 of the outer frame, it is thermally separated from the lower supporting plate 5 which contacts the heat retaining tube of the vertical heat treatment furnace. The substantially uniform heat acts on all the semiconductor wafers 8 during the heat treatment. As described above, the configuration of the semiconductor wafer supporting member 2 described above reduces variations in the local temperature distribution of the semiconductor wafer 8.

Further, the semiconductor wafer supporting member 2 is attached to the outer frame 3
The method of suspending on the upper support plate 4 is not limited to the embodiment of the present invention, and a hook-shaped hook portion is provided on the lower surface of the upper support plate 4 and is formed on the upper end portion of the semiconductor wafer support member 2. The hook portion may be hooked or any other method may be used. However, in any of these structures, the structure of the upper support plate 4 is complicated and the processing cost is increased, so that the one shown in the above embodiment is particularly preferable.

Further, the semiconductor wafer supporting member 2 is attached to the outer frame 3
In order to prevent the semiconductor wafer supporting members 2 from swaying in a state of being suspended from the upper supporting plate 4 of the above, as shown in FIG. 3, only the lower end portions of the respective semiconductor wafer supporting members 2 are connected in a rod shape or a long plate shape. The semiconductor wafers 8 connected by the members 9 and loaded on the respective semiconductor wafer supporting members 2 can be stably held. The above structures are preferred for stability.

When heat-treating the semiconductor wafer 8 based on such a structure, first, a plurality of semiconductor wafer supporting members 2 are hung on the inner lower surface of the upper supporting plate 4 forming the outer frame 3. While lowering, the plurality of semiconductor wafers 8 are vertically stacked in the semiconductor wafer insertion grooves 2a of the plurality of suspended semiconductor wafer supporting members 2 in a horizontal state, and the lower end portions of the respective semiconductor wafer supporting members 2 are connected to each other. The semiconductor wafers 8 connected by the semiconductor wafer supporting members 2 are stably held.

Next, the outer frame 3 on which a plurality of semiconductor wafers 8 are loaded via the semiconductor wafer supporting member 2 is housed in a predetermined vertical heat treatment furnace 10 and the semiconductor wafers are set in a properly set atmosphere. Heat treatment is performed.

As shown in FIG. 4, according to the vertical heat treatment furnace 20 in which the respective constituent members are arranged, the semiconductor wafer supporting member 2 set in the outer frame 3 of the semiconductor wafer boat 1 is
Since the lower end of the semiconductor wafer 8 is arranged so as to be located within the range of the soaking region of the vertical heat treatment furnace 20, the semiconductor wafer 8 is not loaded in the lower part of the furnace having a low temperature. The occurrence of slip defects can be significantly reduced.

In FIG. 4, reference numeral 22 is a soaking tube, a heating member 21 is provided outside the soaking tube 22, and a furnace core tube 23 is provided inside. A heat insulating cylinder 24 is provided below the furnace core tube 23. In the figure, 25
Is a gas supply pipe.

Next, when the degree of occurrence of slip defects was specifically examined by experiments, the following results were obtained. First, as Example 1, a wafer boat constituted by an outer frame made of CVD-SiC coated Si-impregnated SiC and a support member made of silicon was used. As Comparative Example 1, CVD-SiC coated Si-impregnated Si
An integrated wafer boat made of C and an assembled wafer boat made of silicon were used as Comparative Example 2. Then, 100 6-inch wafers were stored in each wafer boat, and an experiment was performed 10 times. Ie 1 total
The number of wafers in which slip defects were generated among the 000 wafers was determined, and the occurrence rate (%) of slip defects was determined. The heat treatment conditions are 1150 ° C., N ₂ gas, O ₂
After heat treatment for 4 hours in a gas atmosphere, heat treatment was performed for 2 hours in an atmosphere of H ₂ gas at the same temperature. Furthermore, the same experiment was conducted on an 8-inch wafer.
Table 1 shows the results.

[0034]

[Table 1]

As described above, according to the wafer boat of the present invention, it is recognized that the occurrence of slip defects can be significantly reduced.

[0036]

As described above in detail, the vertical wafer boat according to the present invention includes a plurality of semiconductor wafer supporting members having a plurality of semiconductor wafer insertion grooves formed at predetermined intervals in the longitudinal direction, and a semiconductor wafer. An outer frame that detachably hangs the upper end portion of the support member is configured as a separate body, and further, since a semiconductor wafer support member that loads a plurality of semiconductor wafers is hung on the outer frame, the semiconductor wafer support member The lower end portion and the lower end portion of the semiconductor wafer boat are thermally separated from each other, and the variation in the local temperature distribution does not occur in the semiconductor wafer. Further, in the vertical heat treatment furnace according to the present invention, since the lower end portion of the wafer boat is located within the soaking region of the heat treatment furnace, there is no local temperature distribution variation in the semiconductor wafer. As a result, it is possible to reduce the occurrence of slip defects in the semiconductor wafer to be heat treated.

Since the outer frame does not require processing such as a semiconductor wafer insertion groove, Si-impregnated SiC, CVD-SiC
The mechanical strength of the wafer boat can be increased by manufacturing an integrated structure by welding or bonding with a material having high strength and high heat resistance such as coated Si-impregnated SiC. Further, in the case where the upper support plate and the lower support plate are integrally fixed to the upper and lower end portions of the column as the outer frame, or if they are assembled detachably,
The mechanical strength of the wafer boat can be increased as compared with the case where only the upper support plate is used. Further, the semiconductor wafer supporting member is easy to process because it has a simple shape in which a tensile force acts only by suspending it on the outer frame.
Materials such as high-purity silicon material and high-purity quartz glass can be used and can be manufactured at low cost. As a result, it can be used at a relatively high temperature without causing boat deformation after heat treatment. Further, since only the semiconductor wafer supporting member has a structure that can be easily attached and detached, even if a part of the semiconductor wafer supporting member is lost, it is extremely easy to replace only that part. You can

As is apparent from the above, according to the present invention, it is possible to manufacture a semiconductor wafer boat which is easy to process and inexpensive, and according to the vertical heat treatment furnace of the present invention, Since it can be located within the soaking region of the semiconductor wafer, the variation of the local temperature distribution does not occur in the semiconductor wafer, the quality of the semiconductor wafer product obtained by the heat treatment is improved, and the reliability is improved. be able to.

[Brief description of drawings]

1 is a perspective view showing an embodiment of a vertical semiconductor wafer boat accommodated for a vertical heat treatment furnace according to the present invention.

FIG. 2 is a perspective view showing a state in which a plurality of semiconductor wafers are loaded on the semiconductor wafer boat shown in FIG.

FIG. 3 is a front view showing a state in which lower end portions of semiconductor wafer supporting members are connected to each other according to another embodiment of the present invention.

4 is a diagram showing a cross section of a vertical heat treatment furnace that accommodates the semiconductor wafer boat of FIG. 1;

[Explanation of symbols]

 1 Wafer Boat 2 Semiconductor Wafer Supporting Member 2a Semiconductor Wafer Insertion Groove 3 Outer Frame 4 Upper Supporting Plate 5 Lower Supporting Plate 6 Support 8 Semiconductor Wafer 9 Connecting Member 20 Vertical Heat Treatment Furnace 21 Heating Member 22 Soaking Tube 23 Furnace Core Tube 24 Insulating Tube 25 gas supply pipe

Front Page Continuation (72) Inventor Jun Yoshikawa 30 Soya, Hadano, Kanagawa Prefecture Toshiba Ceramics Co., Ltd.

Claims (5)

[Claims] 1. An outer frame composed of a plurality of columns and at least an upper support plate integrally fixed to the upper ends of the columns or detachably assembled, and a plurality of outer frames with a predetermined interval in the longitudinal direction. A vertical wafer boat, comprising: a plurality of wafer supporting members having wafer insertion grooves formed therein, and an upper end portion of the wafer supporting members being removably suspended from an upper supporting plate of an outer frame. 2. An outer frame composed of a plurality of columns and an upper support plate and a lower upper support plate integrally fixed to the upper and lower ends of the columns or detachably assembled, and a predetermined interval in the longitudinal direction. And a plurality of wafer supporting members having a plurality of wafer insertion grooves formed therein, and the upper end of the wafer supporting member is removably suspended on an upper supporting plate of an outer frame. boat. 3. An outer frame composed of the plurality of columns and at least the upper support plate is made of Si-impregnated SiC, CV.
The vertical wafer boat according to claim 1 or 2, wherein the vertical wafer boat is made of any one of D-SiC-coated Si-impregnated SiC and quartz glass. 4. The wafer supporting member is made of silicon or CV.
The vertical wafer boat according to claim 1 or 3, wherein the vertical wafer boat is made of one kind of material selected from D-SiC-coated Si-impregnated SiC and quartz glass. 5. In a vertical heat treatment furnace having a furnace core tube, a heating body outside the furnace core tube, and the vertical wafer boat, when the wafer boat is housed in the furnace core tube, an upper support plate of the outer frame of the wafer boat is provided. A vertical heat treatment furnace, wherein the suspended lower end of the wafer supporting member is arranged so as to be located within a soaking region in the furnace core tube.