JP2001110735A - Wafer boat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture an inexpensive wafer boat in which a boat can be easily washed or repaired, and a support rod can be held firmly by a holding member, even in the direction of the rod axial line, and the generation of slip can be reduced. SOLUTION: A wedge-shaped latching structure is adopted as the latching structure of each support rod 11. That is, the latching face of each edge plate 12 and 13 and the latching face of the support rod 11 are defined as inclined planes 20a and 20b inclined with respect to the axial line of the support road 11, and the support rod 11 is pressed to the inclined plane 20a of the edge plates 12 and 13 by a key 14. Thus, a boat 10 can be easily washed or repaired, and the support rod 11 can be held firmly by the edge plates 12 and 13, even in the direction of the road axial line. As a result, a wafer boat can be manufactured easily in which slipages are hardly generated in a silicon wafer W at relatively low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wafer boat,
More specifically, the present invention relates to a wafer boat used for heat-treating a wafer such as a silicon wafer.

[0002]

2. Description of the Related Art For example, when performing a thermal oxidation process for covering the surface of a silicon wafer with a silicon oxide film, a wafer boat for processing a large number of wafers at once is generally used. Known wafer boats include a horizontal wafer boat into which silicon wafers are inserted vertically and a vertical wafer boat into which silicon wafers are inserted horizontally. Of these, a vertical wafer boat has a plurality of supporting rods vertically spanned by a pair of end plates (holding members) vertically separated from each other, and a large number of wafers are inserted into the inner surface of each supporting rod. It has a structure in which the grooves are arranged at a constant pitch along the rod axis direction. Each wafer is inserted into these wafer insertion grooves.

[0003] By the way, there are combinations of raw materials for the support rod and the end plate that cause inconvenience in connection between the two by welding. For example, polysilicon-polysilicon, silicon-silicon, silicon-polysilicon, or the like. In the case of a combination of these materials, the wafer boat necessarily becomes an assembled boat. Such an assembling type also has an advantage that cleaning and repair after use of the boat are facilitated.

Here, a conventional assembling type wafer boat will be described with reference to FIG. FIG. 7 is an enlarged sectional view of a main part of a wafer boat according to this conventional means. The assembled wafer boat 100 has three support rods 101.
have. Each of the support rods 101 is attached to the outer peripheral portion of two spaced-apart end plates 102 via a hooking structure.
It is vertically detachably mounted at 0 degree intervals. On the inner surface of each support rod 101, a number of wafer insertion grooves 10 are provided.
3 are arranged at a constant pitch along the rod axis direction. In this hooking structure, hook-shaped engaging portions 101a are integrally formed at both ends of the support rod 101, respectively. The hook-shaped engaging portion 101a is formed in a shape whose cross section is bent in a substantially U-shape. An engaging hole 1 is provided at the holding position of the support rod 101 of the end plate 102 corresponding to the hook-shaped engaging portion 101a.
02a is pierced. The engagement hole 102a is formed in a shape whose cross section is bent in a substantially L-shape. On the other hand, a shaft hole 1 is provided at a center portion side of each of the engagement holes 102a of the end plate 102.
02b is drilled. A shaft portion 104a of a key 104 having a tongue shape is rotatably inserted into the shaft hole 102b. A key groove 101b is formed on the surface of each hook-shaped engaging portion 101a on the wafer insertion groove 103 side.

At the time of assembling the boat, the hook-shaped engaging portion 101
a into the engaging hole 102a. Then, support rod 1
01 in the outer peripheral direction of the end plate 102, and
01a is pressed against the inner wall surface of the engagement hole 102a. Next, by turning the key 104, the tip 104 b
Is pressed against the bottom of the key groove 101b with a large force. As a result, the support rod 101 is hooked on the end plate 102, and the support rod 101 does not come off the end plate 102. A large number of silicon wafers are inserted into the respective wafer insertion grooves 103 of the wafer boat 100, and the outer peripheral edge of the wafer is supported by the support rod 101 at a plurality of locations.

[0006]

In the conventional assembling type wafer boat, as described above, the support rod 1 is used.
01 and the end plate 102, the hook-shaped engagement portion 10
1a is pressed against the inner wall surface of the engagement hole 102a, and then this engagement state is held with a large pressing force from the center of the end plate 102 using the key 104. However, a hook-shaped engaging portion 101a having a U-shaped cross section and a cross section L
In the engagement with the letter-shaped engagement hole 102a, a fitting intersection of several mm is previously arranged in these engagement portions in the design stage. Therefore, the backlash in the direction perpendicular to the axis of the support rod 101 can be suppressed by the pressing force of the key 104 from the center of the end plate 102 to the outside, but due to the influence of the intersection, the support rod 101 For example, 1
There is a problem that rattling of about 3 mm occurs.

For example, even when a slight external force is applied from the outside when handling a boat, there is a risk that the support rod will tilt and the entire boat will be distorted. Therefore, if the wafer is heat-treated in a heat treatment furnace while the support rod is tilted, there is a possibility that the wafer may slip. Therefore, there is a concern that the quality of the wafer may be reduced, and that the quality of the device and the yield may be reduced.

Accordingly, the inventor of the present invention has conducted intensive studies and found that if the shape of the engaging portion between the support rod and the holding member is made to be a wedge shape having an inclined surface inclined with respect to the axis of the support rod, this support rod can be obtained. Not only in the direction perpendicular to the axis, but also in the direction of the axis, thereby preventing the occurrence of slip on the wafer and finding out that the present invention was completed. .

[0009]

SUMMARY OF THE INVENTION According to the present invention, a boat can be easily washed and repaired, and a supporting rod can be firmly held on a holding member in the axial direction of the rod. The purpose is to provide a wafer boat that can be easily manufactured.

[0010]

According to the first aspect of the present invention, a plurality of support rods for supporting a wafer and both ends of the support rods are detachably held via a hook structure. A wafer boat including a pair of holding members, wherein the latching structure includes an engaging surface formed on the holding member and an engaging surface formed on the support rod engaged with the engaging surface. A wedge-shaped locking structure that is an inclined surface inclined with respect to the axis of the support rod, wherein each of the support rods is pressed against an engagement surface of the holding member by a locking member provided on the holding member. It is a wafer boat to be hung.

The wafer boat may be vertical or horizontal. The type of wafer is not limited. For example, a silicon wafer, a gallium arsenide wafer, or the like can be used. The materials of the support rod and the holding member are not limited. For example, in the order of description of (support rod-holding member), polysilicon-polysilicon, silicon-silicon, silicon-polysilicon, polysilicon-silicon and the like can be mentioned.
The application of the wafer boat is not limited. For example, a boat for thermal oxidation treatment of wafers or a boat used for wafer bonding heat treatment for bonded wafers may be used. The material of the hanging member is not limited. For example, the material may be the same as any of the wafer, the support rod, and the holding member, or may be another material. The mounting position of the hook member on the holding member is not limited. However, it is preferable that the support rod is located closer to the central part than the holding position. In addition, the structure for hanging the support rod by the hanging member is not limited. For example, a key locking structure in which the locking member is used as a key and the key is detachably press-fitted into a key groove formed in the support rod may be used. Alternatively, a cotter structure may be used in which the hanging member is a cotter, which is detachably press-fitted into a tapered groove formed in the support rod. The angle of inclination of the engaging surface of the support rod and the engaging surface of the engaging member is not limited. Preferably, 20 to 8
5 degrees.

The invention according to claim 2 is the wafer boat according to claim 1, wherein the support rod is made of polycrystalline silicon. The material of the holding member may be silicon or polysilicon. Further, by using silicon, it is possible to reduce contamination of the wafer.

[0013]

According to the present invention, at the time of assembling the boat, after the inclined surface of the holding member is engaged with the inclined surface of the support rod, the support rod is engaged with the engaging surface of the holding member (the inclined surface of the holding member). ) With great force. Due to the pressing force of the locking member, rattling of the support rod in a direction perpendicular to the rod axis is suppressed. In addition, since the engaging surface of the holding member and the engaging surface of the support rod pressed by the holding member are inclined surfaces inclined with respect to this axis in a plane along the axis of the support rod, It is possible to prevent rattling in the axial direction of the rod. As a result, it is possible to prevent the occurrence of slip on the wafer during the heat treatment. Further, since such a wedge-shaped hooking structure is employed, the manufacture of the wafer boat is facilitated, and the cost can be reduced. Further, since the support rod is made of polysilicon, occurrence of slip can be suppressed. At the same time, contamination of the wafer can be reduced.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. Here, a vertical wafer boat having a silicon support rod and a holding member is taken as an example. FIG. 1 is an enlarged sectional view of a main part of a wafer boat according to one embodiment of the present invention. FIG. 2 is a front view of a wafer boat according to one embodiment of the present invention. FIG. 3 is a side view of a wafer boat according to one embodiment of the present invention. FIG. 4 is a sectional view taken along line S4-S4 in FIG. FIG. 5 is an enlarged plan view of a main part of the wafer boat according to one embodiment of the present invention. FIG. 6 is a plan view of a main part of a wafer boat according to one embodiment of the present invention.

2 and 3, reference numeral 10 denotes a vertical wafer boat according to one embodiment of the present invention.
The wafer boat 10 has a large number of silicon wafers W
(See FIG. 6), two parallel support rods 11 for horizontally supporting, and a lower end plate (holding member) 12 having a substantially circular shape in a plan view, and both ends of each support rod 11 being detachably held. This is an assembling type wafer boat including an upper end plate (holding member) 13 which is horizontally long when viewed. Each support rod 11
Are formed of vertically arranged circular pillars of circular cross section made of silicon, similarly to the silicon wafer W. The two support rods 11 are located on the same circle around the center point of the corresponding end plates 12 and 13 at the outer edges of the end plates 12 and 13.
They are arranged at intervals of 80 degrees. Lower end plate 12, Upper end plate 13
Is also the same silicon as the wafer W. Lower end plate 12
On the lower surface of the outer peripheral portion are provided three short supporting projections 12b at intervals of 120 degrees (see FIG. 4). On the inner surface of each support rod 11, a wafer insertion groove 1 having a constant pitch is provided.
Many 1a are formed in the rod axis direction. Also,
At both ends of each support rod 11, a hook-shaped engagement portion 11b curved in a U-shape toward the inner surface of the rod is integrally formed. For holding the support rods 11 on the end plates 12 and 13, a key locking structure including a wedge-shaped engaging portion described later is employed. Next, this key hooking structure will be specifically described.

As shown in FIGS. 1 to 3, the key locking structure mainly includes a silicon key (locking member) 14 supported on the outer edges of both end plates 12 and 13, and each support rod. 11 and a pair of wedge-shaped engaging portions 20 arranged between the lower hook-shaped engaging portion 11b and the lower end plate 12 with the key groove 15 formed in both hook-shaped engaging portions 11b. Consists of Key 14
Is a tongue-shaped key body 14 having a rounded tip in plan view.
a and a shaft portion 14b arranged orthogonally to the rear surface of the base of the key body 14a. This shaft portion 14b
Are inserted into a pair of shaft holes 12a, 13a formed in the vicinity of the outer edges of the end plates 12, 13, respectively.

The key groove 15 is formed at an end on the wafer insertion groove 11a side of a back portion protruding outward in a U-shape from the hook-shaped engaging portion 11b, and has an arc shape in plan view. It is a groove (see FIG. 5). Each shaft hole 12a, 13a of the end plates 12, 13
Two engagement holes 16 each having a rectangular shape in plan view and an L-shape in cross section are formed further outward in the radial direction.
The engagement hole 16 is a hole into which the hook-shaped engagement portion 11b is engaged. A latching piece 16a is provided on the opposite side of each of the engagement holes 16 from the shaft holes 12a and 13a. These hook pieces 16a are formed on the inner surfaces of the end plates 12, 13. Each hook 16a has a hook-shaped engaging portion 11b.
Is hooked. A stopper pin 21 for positioning the key 14 hooked to the key groove 15 is vertically provided between the corresponding shaft hole 13a and the engagement hole 16 on the lower surface of the upper end plate 13. I have.

Next, the wedge-shaped engagement portion 20 will be described with reference to FIGS. Lower end plate 12
A substantially crescent-shaped overlay portion 12c is integrally formed on the upper surface of the outer edge portion near both engagement holes 16 in plan view. An inclined surface 20a, which is an engagement surface with the corresponding hook-shaped engagement portion 11b, is formed on a surface of the end plate 12c on the center side of the end plate. These inclined surfaces 20a are set to θ20 with respect to this axis.
It is inclined only by degrees. Also, the inclined surface 20b of the hook-shaped engaging portion 11b corresponding to each inclined surface 20a is
Is formed on the outer surface. The wedge-shaped engaging portion 20
It is constituted by inclined surfaces 20a and 20b that abut and engage with each other.

Next, the wafer boat 10 of this embodiment will be described.
How to assemble will be described. As shown in FIG. 1 to FIG. 3, two support rods 11 are vertically bridged at every 180 degrees in the circumferential direction of the lower end plate 12 between both end plates 12 and 13 which are arranged vertically. Next, the work of hooking each support rod 11 to the end plates 12 and 13 by the key hooking structure will be described. That is, the hook-shaped engaging portions 11b of the corresponding support rods 11 are inserted into the engaging holes 16 of the end plates 12 and 13 with their U-shaped opening sides directed outward of the end plates 12. Next, each support rod 11 is moved in parallel to the outside of the end plate 12. As a result, the bent front end portion 11c of each hook-shaped engaging portion 11b is engaged with the engaging piece 16a of the engaging hole 16.
Hanged on. At the same time, the inclined surface 20a of the end plate 12
And the inclined surfaces 20b of the support rod 11 are brought into contact with each other and engaged. Note that the outer surface of the end plate 12 and the outer surface of the distal end portion 11c of the hook-shaped engaging portion 11b are flush.

Thereafter, each key 14 is rotated toward the corresponding support rod 11, and the tip of each key body 14a is strongly pressed against the corresponding key groove 15. That is, the distance from the intermediate point of the arc surface of the key groove 15 to the rotation center of the shaft 14b at this time is shorter than the distance from the tip of the key 14 to the rotation center of the shaft 14b. Therefore,
By the key 14, the support rod 11 is firmly fixed at a predetermined positioning position. At this time, this key 1
By the pressing force of 4, the backlash of the support rod 11 in the direction orthogonal to the axis of the support rod 11 is suppressed. In addition, the inclined surface 20a of the lower end plate 12 and the inclined surface 20b of the support rod 11 pressed by the support rod 1
Since it is inclined by a predetermined angle with respect to one axis, it is possible to prevent rattling in the rod axis direction. As a result, it is possible to prevent the occurrence of slip on the silicon wafer W during the wafer heat treatment. Further, since the wedge-shaped hooking structure having the wedge-shaped engaging portion 20 that can obtain such an effect is adopted, the manufacture of the wafer boat 10 becomes easy and the cost can be reduced.

Here, using the wafer boat 10 of one embodiment, the silicon wafers W inserted into the upper, middle, and lower portions of the boat three by three are subjected to a hydrogen annealing treatment to perform a slip generation evaluation test. We report the result when we went. The temperature in the furnace of the hydrogen annealing furnace is 1200 ° C., the heating time is 1 hour, and the supply rate of hydrogen gas in the furnace is 30 L / min. This hydrogen annealing test was performed twice. Table 1 shows the test results. The defective rate was determined based on the percentage of slip observed visually.

[0022]

[Table 1]

As is clear from Table 1, the total slip occurrence rate of the two times was about 5.6%. As a comparative example, a case where the same silicon wafer is subjected to hydrogen annealing under the same conditions is shown. The wafer boat used at this time has the conventional structure shown in FIG. The slip generation rate in the comparative example was about 27.8%.

[0024]

According to the present invention, the engaging surface of the holding member and the engaging surface of the support rod are inclined with respect to the axis, and the support rod is inclined by the hook member. Since the structure for pressing the boat is adopted, it is easy to wash and repair the boat, and the support rod can be firmly held on the holding member also in the rod axial direction.
This makes it difficult for the wafer to slip. Also,
The wafer boat itself can be easily manufactured, and can be manufactured at relatively low cost. Further, when the support rod is made of polysilicon, it is possible to reduce the contamination of the wafer and more effectively reduce the occurrence of slip.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part of a wafer boat according to one embodiment of the present invention.

FIG. 2 is a front view of a wafer boat according to one embodiment of the present invention.

FIG. 3 is a side view of the wafer boat according to one embodiment of the present invention.

FIG. 4 is a sectional view taken along line S4-S4 in FIG. 3;

FIG. 5 is an enlarged plan view of a main part of the wafer boat according to one embodiment of the present invention.

FIG. 6 is a plan view of a main part of the wafer boat according to one embodiment of the present invention.

FIG. 7 is an enlarged sectional view of a main part of a wafer boat according to a conventional means.

[Explanation of symbols]

 Reference Signs List 10 wafer boat, 11 support rod, 12 lower end plate (holding member), 13 upper end plate (holding member), 14 key (hook member), 20 engaging portion, 20a inclined surface (engaging surface), 20b inclined surface ( Engagement surface).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshihisa Nonogaki 1-5-1, Otemachi, Chiyoda-ku, Tokyo Within Mitsubishi Materials Silicon Corporation (72) Inventor Tetsuya Okuda 3-25, Higashishinagawa, Shinagawa-ku, Tokyo No. 21 F-term in Technisco Co., Ltd. (reference) 5F045 AA20 AB32 BB13 BB14 EM01 EM02 EM08 EM09

Claims (2)

[Claims] 1. A wafer boat comprising: a plurality of support rods for supporting a wafer; and a pair of holding members for detachably holding both ends of the support rods via a hooking structure. An engaging surface formed on the holding member, and an engaging surface formed on the support rod engaging with the engaging surface, the inclined surface being inclined with respect to the axis of the support rod; A wafer boat, wherein each of the support rods is pressed and latched against an engagement surface of the holding member by a latching member provided on the holding member. 2. The wafer boat according to claim 1, wherein said support rod is made of polycrystalline silicon.