JPH06169010A - Vertical boat and its manufacture - Google Patents

Abstract

PURPOSE:To prevent slip and to make the deflection of a wafer smaller, even if heat treatment is performed loading a large size wafer, by providing supporting protrusions at supporting parts for supporting members, and arrang ing those supporting protrusions within a specific range crossing the peripheral brim of the wafer 1 and reaching parts closer to its center. CONSTITUTION:A plurality of supporting members 3 and 4 are arranged in a vertical direction, and a plurality of semiconductor wafers 1 are loaded respectively in a plurality of slits 7 and 8 formed in those supporting members 3 and 4 at specified intervals. In a vertical boat such as that, supporting protrusions 11 and 12 are provided at supporting parts for supporting member 3 and 4. They are so arranged that the supporting protrusions 11 and 12 may be at 50-90% of the radius of the wafer 1 crossing the peripheral brim of the wafer 1 and reaching parts closer to its center. For example, slits 7 and 8 are formed by cutting platy supporting members 3 and 4 having cross sections in arc shapes, made by cutting parts of pipes by about 2/3 of the widths or more, for example, and supporting protrusions 11 and 12 having narrow areas are provided at the tip parts of supporting parts formed by them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical arrangement for arranging a plurality of supporting members in a vertical direction and loading a plurality of semiconductor wafers on a plurality of slits formed at predetermined intervals on the supporting members. A mold boat and a manufacturing method thereof.

[0002]

2. Description of the Related Art In a semiconductor wafer oxidation / diffusion process, a large number of semiconductor wafers are loaded on a wafer boat,
The wafer boat is carried into the diffusion furnace as it is, and a desired heat treatment is performed therein.

A vertical boat or a horizontal boat is used depending on the type of diffusion furnace.

In a conventional vertical boat, a plurality of (for example, four) rod-shaped support members are vertically arranged to support a plurality of wafers horizontally or in a state in which they are slightly inclined. A plurality of slits are formed at predetermined intervals on those support members. A plurality of semiconductor wafers are loaded in the plurality of slits.

In the conventional vertical boat, all the supporting members are usually rods having the same sectional shape. For example, the cross-sectional shape was circular or square. The slit formed on the rod having such a cross-sectional shape had an arc shape whose inner part was along the outer circumference of the wafer, had a small surface in contact with the wafer, and was along the outer circumference of the wafer. In other words, the width of the supporting surface formed by the slit in the wafer circumferential direction was small.

On the other hand, as a means for relieving the load stress of a large-sized wafer, a shape in which an arc-shaped plate is fixed to a support rod is proposed as in Japanese Utility Model Laid-Open No. 62-128633, but it is difficult to obtain surface accuracy. It will be expensive.

[0007]

The boat is exposed to a high temperature during heat treatment while the wafer is supported by the supporting member regardless of whether the supporting member is rod-shaped or plate-shaped. Then, since the conventional vertical boat supports the outer peripheral edge of the wafer, the amount of bending of the wafer increases due to its weight, especially as the size of the wafer increases. As a result, the wafer is deformed or slips, so-called crystal transition occurs, which adversely affects the product yield.

Further, when the supporting surface of the supporting member is in contact with only the outer peripheral edge of the wafer, the load stress concentrates on the specific supporting member. Therefore, the frequency of slips increases, especially as the size of the wafer increases.

In order to load and unload the wafer into and from the boat, the distance between the pair of support members located on the wafer insertion start side is made larger than the outer diameter of the wafer. Therefore, in a state where the wafers are loaded on the predetermined position of the boat, the angle formed between the front end of the support member located on the wafer insertion start side, the center of the wafer, and the wafer insertion direction is slightly smaller than 90 degrees (for example, It is best to use a structure that is several degrees apart, but in such a structure, the center of gravity of the wafer is located between the front ends of two opposing support members located on the wafer insertion start side or in the vicinity thereof. As a result, the load is unevenly distributed on the support member located on the insertion start end side of the wafer. For example, a load stress of 70 to 90% is applied to the pair of support members located on the insertion start end side of the wafer.

Further, the thermal stress due to the temperature difference between the supporting portion of the supporting member of the boat and the wafer is also added during the heat treatment, and the frequency of slips increases especially as the wafer becomes larger.

When heat-treating a wafer, heat is transferred from the diffusion furnace by radiation or heat transfer, but a plurality of slits (grooves) are formed in the rod-shaped support member at predetermined intervals.
There is also heat transfer from that location to the wafer, which is a factor of the local temperature distribution inside the wafer. The thermal stress due to the weight of the wafer and the thermal temperature distribution causes the slip transition of the wafer between the pair of opposing support members located on the insertion start end side of the wafer, thus lowering the heat treatment yield of the wafer.

The present invention solves the above-mentioned drawbacks of the prior art, and provides a vertical boat in which a large size wafer is loaded and heat treatment is not performed, and slippage does not occur, and the amount of wafer deflection can be reduced. The purpose is to do.

[0013]

According to a first aspect of the present invention, a plurality of supporting members are arranged in a vertical direction, and a plurality of semiconductor wafers are respectively provided in a plurality of slits formed at predetermined intervals on the supporting members. In a vertical boat for loading, a supporting protrusion is provided on a supporting portion of a supporting member, and the supporting protrusion exceeds the outer peripheral edge portion of the wafer and is closer to the center than the radius of the wafer by 50.
The gist is a vertical boat, which is characterized in that it is arranged so as to be 90%.

A second aspect of the present invention is a vertical die for arranging a plurality of supporting members in a vertical direction and loading a plurality of semiconductor wafers in a plurality of slits formed at predetermined intervals on the supporting members. In a boat manufacturing method, an elongated plate (for example, a shape close to a pipe or a slightly similar "J")
The shape of a plate having a cross-sectional shape such as a letter, a "U", a "C", or a "he" or a "ku", an "L", and a "V"
Shape, the shape of a plate having an angle, for example, 45 ° to 150 °, such as a letter “Y”), forms a first slit over about ⅔ or more of the width of the plate, and then one side of the plate A gist is a method of manufacturing a vertical boat, which is characterized in that a supporting protrusion having a narrow area is formed at a tip portion of a supporting portion by cutting a second slit from an end surface into a first slit.

[0015]

According to the vertical boat of the present invention, it is possible to reduce the occurrence of wafer bending, warpage and slippage. In particular, the effect of suppressing the occurrence of slip is very large. By using the vertical boat of the present invention, it is possible to improve the yield and reliability of products and shorten the heat treatment process time.

More specifically, since the supporting projections support the portion of the wafer near the center of the wafer beyond the outer peripheral edge portion of the wafer, the supporting portion of the supporting member is provided on the outer peripheral edge portion of the wafer to be heat-treated during the heat treatment. Do not touch. As a result, the drawbacks found in the conventional vertical boat supporting the outer peripheral edge of the wafer are eliminated. For example, when a semiconductor wafer is loaded on a predetermined position of a boat, the center of gravity of the wafer is located considerably on the insertion side from the supporting portions of the two opposing supporting members located on the insertion start end side of the wafer. The load on the supporting member located on the starting end side is reduced. In other words, the load is properly distributed on all the support members. Therefore, the risk of the wafer slipping is reliably avoided.

Further, according to the vertical boat of the present invention, the supporting projections support the portion of the wafer near the center of the wafer beyond the outer peripheral edge portion of the wafer. Thus, the amount of bending due to the weight of the wafer is suppressed.
This effect becomes remarkable especially as the size of the wafer increases. As a result, it is possible to prevent the wafer from being deformed or slipped to cause crystal transition, and the product yield is improved.

Further, since the supporting protrusions support the wafer near the center of the wafer beyond the outer peripheral edge of the wafer, heat transfer to the wafer from the plurality of grooves formed in the rod-shaped supporting member is eliminated. The local temperature distribution inside the wafer is suppressed as much as possible, and the generation of thermal stress due to the temperature difference between the supporting portion of the boat supporting member and the outer peripheral portion of the wafer during the heat treatment is effectively suppressed. Therefore, the slip transition of the wafer caused by the thermal stress due to the weight of the wafer and the thermal temperature distribution is eliminated, and the heat treatment yield of the wafer is improved.

According to the manufacturing method of the present invention, it is possible to extremely easily and highly accurately manufacture the vertical boat that exhibits the remarkable effects as described above. In particular, when a large number of vertical boats having highly accurate slit widths and slit intervals are produced, the manufacturing method of the present invention exerts an outstanding effect.

Further, preferably, the strength is improved by increasing the section modulus of the supporting member as compared with the conventional vertical boat. The preferred range of section modulus is 0.3-
3.0 cm ³ (particularly preferably 0.5~2.5cm ³⁾ is.

[0021]

1 to 7 show a vertical boat according to a first embodiment of the present invention, and FIG. 8 shows a vertical boat according to a second embodiment of the present invention. In any of the embodiments, the vertical boat is for loading a large number of wafers 1, and three or more (typically four) support members 3 are provided between the pair of upper and lower plate-shaped fixing means 2. 4, 104 are arranged in the vertical direction. A plurality of slits 7, 8 formed in the supporting members 3, 4, 104 at predetermined intervals along the longitudinal direction,
A plurality of wafers 1 are loaded on each 108. Each of the support members 3, 4, 104 is in the shape of an elongated plate.

The slits 7, 8 and 108 are about 2/3 or more of the width of the plate-like support members 3, 4 and 104 (preferably 3/4).
The above is formed by cutting. In addition, the support protrusion 11 having a narrow area is provided at a predetermined portion (for example, the tip portion) of the support portion defined by the slits 7, 8, and 108.
12, 112 are provided so that the supporting protrusions 11, 12, 112 support the portion of the wafer 1 near the center thereof over the outer peripheral edge portion of the wafer 1. For example, the supporting points of the wafer 1 by these supporting protrusions 11, 12, 112 are arranged concentrically from the center 1a of the wafer 1, and come to the area P of 50 to 90% of the radius of the wafer 1 to reach the outside of the wafer 1. It is preferable that the wafer 1 is arranged so as to support the central portion of the wafer 1 beyond the peripheral portion.

Although various plate shapes can be adopted for the plate-like support members 3, 4, 104, in the vertical boat of the first embodiment shown in FIGS. 1 to 7, the plate-like support members 3, 4 are circular. An arc-shaped or arc-shaped cross-section obtained by cutting a part of the tube is used. The other non-linear shape is preferably a "ku" shape, an "L" shape, a "J" shape, a boomerang shape, or another curved surface shape. It is possible to make the thickness gradually smaller as it goes forward. In the embodiment shown in FIG. 8, the support member 104 is in the form of a circular tube as a whole. These plate-like support members 3, 4, 104
Can be used in various combinations, including shapes not shown.

By providing the supporting protrusions, it is possible to avoid supporting contact at the outer peripheral edge of the wafer, and avoid stress concentration at the outer peripheral edge of the wafer and heat conduction from the boat.

The height of the supporting protrusions may be such that the outer peripheral edge of the wafer does not touch, but considering gas replacement, a height of 0.3 to 3 mm is desirable. Further, as shown in the figure, by providing a plurality of first slits, heat conduction from the boat to the wafer and gas retention between the wafer and the supporting portion can be prevented.

It is desirable that the wafer support position is a position where the amount of wafer deflection and the load stress are small.

The material of the boat is quartz glass, silicon carbide,
Examples thereof include carbon, single crystal, polycrystalline silicon, and Si-impregnated silicon carbide, and those having high purity, heat resistance, and corrosion resistance are desirable. In the case of quartz glass, welding is easy, but in the case of other materials, an assembly type is also conceivable.

Further, although four supporting members are used in the illustrated embodiment, the present invention is not limited to this.

Each of the first and second embodiments will be described in detail below.

First Embodiment of FIGS. 1 to 7 First, the vertical boat of the first embodiment shown in FIGS. 1 to 7 will be described. In this first embodiment, two vertical boats having different curvatures are used.
Various types of plate-shaped support members 3, 4 having a semi-circular cross section are used. The two opposing support members 3 located on the insertion start end side of the wafer 1 are plate-like support members having a large curvature and a semi-circular cross section, and a large number of slits 7 are arranged at predetermined intervals D1 (see FIGS.
It is formed by cutting up to about 5/6 of the width of the plate-shaped support member 3 for each 5). A support protrusion 11 having a narrow area (for example, 10 to 150 mm ² ) is provided at the tip of the support portion defined by the slit 7, and the support protrusion 11 is located near the center of the wafer 1 beyond the outer peripheral edge portion of the wafer 1. It is designed to support P.

On the other hand, 2 which is located on the rear end side of the wafer 1 is inserted.
The two opposing support members 4 are plate-shaped support members having a semi-arcuate cross section with a small curvature, and a large number of slits 8 have a width of about 4 of the plate-shaped support member 3 at predetermined intervals D2 (FIGS. 6 to 7). / 5
It is formed by cutting up to. A narrow area (for example, 10 to 5) is formed at the tip of the supporting portion defined by the slit 7.
0 mm ² ) supporting protrusions 12 are provided so that the supporting protrusions 12 extend beyond the outer peripheral edge portion of the wafer 1 and are closer to the center P of the wafer 1.
To support.

The aforementioned slits 7 and 8 are composed of first slits 7a and 7b having a relatively wide width and second slits 7b and 8b having a relatively narrow width.

Preferably, the supporting points of the wafer 1 by the supporting projections 11 and 12 are arranged concentrically from the center 1a of the wafer 1 in a state where the wafer 1 is loaded on a predetermined position of the boat. Moreover, the concentric circles are arranged so as to be in the region P of 50 to 90% (more preferably 65 to 85%) of the radius of the wafer 1, and the supporting points of the wafer 1 are arranged so as to exceed all the outer peripheral edge portions of the wafer 1. Is preferred.

A preferred arrangement method or distribution method of the support points of the wafer 1 by the support projections 11 and 12 will be described. The projection 11 of the support member 3 located on the insertion start side of the wafer 1 and the center of the wafer 1. The arrangement is such that the angle A formed by 1a and the insertion direction X of the wafer 1 is approximately 75 to 180 degrees (preferably 95 to 140 degrees). On the other hand, the angle B formed by the protrusions 12 of the two opposing support members 4 located on the insertion rear end side of the wafer 1, the center 1a of the wafer 1, and the insertion direction X of the wafer 1 is about 30 to 120 degrees (preferably. Is 30 to 80 degrees).

By adopting a different method of arranging the supporting points or distributing method, the two supporting members located on the insertion start end side of the wafer 1 in a state where the wafer 1 is loaded at a predetermined position of the boat. The protrusion 11 of No. 3 and the protrusion 12 of the other two supporting members 4 located on the rear end side of the wafer 1 on the other side pass through the center 1 a of the wafer 1 and the insertion direction X of the wafer 1. If it is axisymmetric with respect to a parallel line M and is also axisymmetric with respect to a line N passing through the center 1a of the wafer 1 and perpendicular to the insertion direction X of the wafer 1, all supports A load equal to the point is applied, and the load balance of the four protrusions becomes good.

An example of a method of manufacturing the support member 3 used in the embodiments of FIGS. 1 to 7 will be described. First, as shown in FIG. 4, a plate-shaped support member 3 having a semi-arcuate cross section with a large curvature is obtained. Cut the circular tube to the specified width. For example, outer diameter R1
Is 40 mm and the inner diameter R2 is 34 mm, and the angle between the center O1 and both ends of the plate-like support member 3 having a semi-arcuate cross section is set to about 100 degrees. continue,
A width W1 (for example, 7 m) is provided on the plate-like support member 3 having a semi-circular cross section at predetermined intervals D1 (for example, 12.7 mm).
m) and an angle of 60 to 80 degrees from the center O1 (FIG. 4).
The first slit 7a is opened using a means such as a laser beam machine, a high-pressure jet stream, a milling machine, a lathe, or a diamond cutter over a range of the distance L1 in FIG. At that time, a remaining portion 3b of a few degrees from the center O1 is left at the one side end surface 3a of the plate-shaped supporting member 3 having a semi-circular cross section. The remaining portion 3c on the other end side functions as a pillar.

Next, in the remaining portion 3b of the plate-like support member 3, the width W2 (for example, 3. from the side end surface 3a to the first slit 7a).
2 mm) of the second slit 7b is cut by a diamond cutter to form a wafer supporting protrusion 11 having a narrow area at the tip of the wafer supporting portion as shown in FIG. The height H of the protrusion 11 is, for example, 1.9 mm.

Next, an example of a method of manufacturing the plate-shaped supporting member 4 having a semi-arcuate cross section with a smaller curvature used in the embodiment of FIGS. First, a circular tube having a small curvature is cut into a predetermined width. For example, by cutting a circular tube having an outer diameter R3 of 17.5 mm and an inner diameter R4 of 10 mm, the angle formed by the center O2 and the both ends of the plate-shaped support member 4 having a semicircular arc cross section becomes approximately 225 degrees. To do so. Subsequently, in accordance with the predetermined spacing D1 (for example, 12.7 mm) set in the plate-shaped support member 3 having the semi-circular cross-section, the plate-shaped support member 4 having the semi-circular cross-section has a predetermined spacing D2. (For example, 12.7m
For each m), the first slit 8a having a width W3 (for example, 7 mm) and an angle of 180 degrees from the center O2 is opened using a laser processing machine, a high-pressure jet stream, a milling machine, a lathe, a diamond cutter, or the like. At that time, center O on both side edges
When viewed from 2, the remaining portion 4b of about 20 degrees and the remaining portion 4c of about 40 degrees remain. Next, a second slit 8b having a width W4 (for example, 3.2 mm) is cut with a diamond cutter from the side end surface 4a of the plate-shaped support member 4 having a semi-circular cross section to the first slit 8a in the remaining portion 4b of about 20 degrees. As a result, as shown in FIG. 7, a wafer supporting protrusion 12 having a narrow area is formed at the tip of the wafer supporting portion. The height of the protrusion 12 is, for example, 1.9 mm, and the width W5 of the protrusion 12 is, for example, about 3 m.
m.

The four plate-shaped supporting members 3, 4 having a semi-circular cross section, including the slits 7, 8, are arranged line-symmetrically with respect to the insertion direction X of the wafer 1. However, the present invention is not limited to such an arrangement example.

Second Embodiment of FIG . 8 FIG . 8 shows a second embodiment of the present invention.

Four support members 104 having a circular tubular cross section are arranged parallel to each other in the longitudinal direction. These support members 10
Although fixing means are provided at the upper end and the lower end of 4 respectively as in the embodiment of FIG. 1, they are not shown. These supporting members 104 may have the same diameter, but the two opposing supporting members 104 located on the insertion start end side of the wafer 1 have a large diameter in order to secure the passage of the wafer 1. The two opposing support members 104 located on the rear end side of the wafer 1 for insertion have a small diameter in order to reduce the weight as much as possible. The plate-shaped support members 104 having different thicknesses may be used in consideration of mechanical strength. In any case, the support member 104 has a number surface coefficient of 0.3 to 3.0 cm ³ (preferably 0.5 to 2.5).
cm ³ ).

A plurality of slits 108 are formed in both support members 104 at a predetermined same interval. For example, first wafer 1
The two opposing support members located on the insertion start end side of the circular cylindrical support member 5 have a large number of first slits at predetermined intervals.
It is formed by cutting each side to about 2/3 of the width. On the other hand, in the two opposing support members located on the insertion rear end side of the wafer 1, a large number of first slits are provided on the two opposing support members 10 located on the insertion start end side of the wafer 1.
In the same manner as in 4, cut from both sides of the support member to about 3/4 of the width. At that time, leave the rest in two places.
Next, by cutting a second slit having a predetermined width (for example, 3.2 mm) from one end surface of each supporting member to the first slit with a diamond cutter, a wafer having a small area is formed at the tip of the wafer supporting portion. The support protrusion 112 is formed. The height of the protrusion 112 is, for example, 1.9 mm, and the width of the protrusion 12 is, for example, about 3 mm.

A narrow area (for example, 5 to 50 m) is formed at the tip of the supporting portion defined by these slits 108.
The support protrusion 112 of m ² ) is configured to support a portion of the wafer 1 near the center thereof over the outer peripheral edge portion of the wafer 1.
Preferably, in the state where the wafer 1 is loaded at a predetermined position of the boat, the support points of the wafer 1 by the above-mentioned support protrusions 112 are arranged concentrically from the center 1a of the wafer 1.
The concentric circles should be in the region P of 50 to 90% of the radius of the wafer 1, and all the supporting points of the wafer 1 should be in the wafer 1.
It is arranged so as to exceed the outer peripheral edge of the.

Further, a preferable arrangement method or distribution method of the support points of the wafer 1 by these support protrusions 112 is the same as that of the first embodiment shown in FIGS.

It should be noted that, in both the embodiment shown in FIGS. 1 to 7 and the embodiment shown in FIG. 8, in the method for manufacturing a supporting member, after forming the first slit, all supporting members are fixed to the fixing means,
After that, when the second slit is formed, the processing area is reduced, and the accuracy of the entire slit is improved because it is processed later.

It is also preferable that Si is impregnated after forming the first slit and then the second slit is formed.

The vertical boat for 8-inch diameter wafer shown in FIGS. 1 to 7 was manufactured from a silicon single crystal and its characteristics were measured.

The deflection amount of the wafer shown in Table 1 is obtained by simulation by a computer and measurement by a laser micrometer. It was found that the conventional boat of four types using the four supporting members flexes 30 μm or more, whereas the product of the present invention has a flexure of 5 μm or less, and the amount of flexure is significantly small.

Further, heat treatment was performed to examine the wafer warp and the occurrence of slip. Table 2 shows the results of measuring the amount of wafer warpage after oxidation at 1000 ° C. for 100 hours with a laser micrometer.

Table 3 shows the degree of slip generation after heat treatment. It can be seen that both are improved by the present invention.

As described above, the product of the present invention was found to be effective in reducing the occurrence of wafer bending, warpage, and slip as compared with the conventional boat. In particular, the effect of suppressing the occurrence of slip is great, and avoiding contact with the boat stanchions by having the projections is a major factor.

[Brief description of drawings]

FIG. 1 is a sectional view taken along the line II of FIG. 2, showing the outline of a vertical boat according to a first embodiment of the present invention.

FIG. 2 is a front view showing an outline of the vertical boat of FIG. Only the slits in the upper region and the lower region are shown representatively, and the slits in the intermediate region are omitted for simplicity of the drawing.

FIG. 3 is a left side view schematically showing the vertical boat of FIG. Figure 2
Similarly, only the slits in the upper region and the lower region are shown representatively, and the slits in the intermediate region are omitted for simplicity of the drawing.

FIG. 4 is a diagram showing a manufacturing process of a support member having a large curvature of the vertical boat of FIG. 1, (A) is a view of a part of the support member as viewed from the left side of (B), and (B). Is (A) IV
FIG. 4 is a sectional view taken along line IV-IV.

5 is a view showing a support member of the vertical boat of FIG. 1,
(A) is a view of a part of the support member as viewed from the left side of (B), and (B) is a cross-sectional view taken along line VV of (A).

6A and 6B are views showing a manufacturing process of a support member having a small curvature of the vertical boat of FIG. 1, FIG. 6A is a view of a part of the support member as viewed from the left side of FIG. Is VI of (A)
FIG. 6 is a cross-sectional view taken along the line VI.

FIG. 7 is a view showing a support member having a small curvature of the vertical boat of FIG. 1, (A) is a view of a part of the support member as viewed from the left side of (B), and (B) is (A). 7 is a cross-sectional view taken along line VII-VII in FIG.

FIG. 8 is a sectional view showing a part of a vertical boat according to a second embodiment of the present invention and corresponding to the view of the corresponding part in FIG. 1.

[Explanation of symbols]

 1 Wafer 1a Wafer center 3,4,104 Support members 7,8,108 Slits 7a, 8a First slits 7b, 8b Second slits 11,12,112 Support protrusions ◆

[Table 1]

[Table 2]

[Table 3]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuno Kiyono 378 Oguni-machi, Oguni-cho, Nishikitama-gun, Yamagata Prefecture Oguni Factory, Toshiba Ceramics Co., Ltd. (72) Hideo Nakanishi 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd. Company Development Laboratory (72) Inventor Takashi Tanaka 30 Soya, Hadano City, Kanagawa Prefecture Toshiba Ceramics Corporation Development Laboratory

Claims (2)

[Claims] 1. A vertical boat for arranging a plurality of support members in a vertical direction and loading a plurality of semiconductor wafers in a plurality of slits formed at predetermined intervals on the support members. 2. A vertical boat characterized in that a supporting protrusion is provided on the supporting portion of the wafer, and the supporting protrusion is arranged so as to be 50 to 90% of the radius of the wafer toward the center beyond the outer peripheral edge of the wafer. 2. A method for manufacturing a vertical boat for arranging a plurality of support members in a vertical direction and loading a plurality of semiconductor wafers in a plurality of slits formed at predetermined intervals on the support members. , Forming a first slit in the width direction of the elongated plate over about ⅔ or more of the width of the plate, and then cutting a second slit from one side end surface of the plate into the first slit, thereby forming a tip portion of the support portion. A method for manufacturing a vertical boat, comprising forming a support protrusion having a narrow area.