JPH06151347A - Boat for vertical heat treatment furnace - Google Patents

Abstract

PURPOSE:To provide a boat, for a vertical heat treatment furnace, wherein it prevents the slip of a wafer from being caused. CONSTITUTION:A plurality of supports 14 are coupled by an upper-side coupling plate 15 and a lower-side coupling plate 12. A semiring-shaped wafer holding plate 21 is installed on the same height position of the individual supports 14. A wafer 14 is supported and mounted on the wafer holding plate 21 in a line contact manner or in a face contact manner. Consequently, the weight of the wafer W is dispersed by the wafer holding plate 21. As a result, a slip due to a thermal stress during a heat treatment is not caused at the wafer W itself on a wafer mounting part.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a boat for a vertical heat treatment furnace,
Specifically, it relates to the wafer mounting part.

[0002]

2. Description of the Related Art A conventional boat for a vertical heat treatment furnace is installed upright in the vertical heat treatment furnace. This boat has a plurality of columns, and a large number of wafer holding grooves are formed facing each other along the longitudinal direction thereof. These wafer holding grooves are for mounting thin plate-shaped and circular wafers (silicon and other semiconductor wafers). When this wafer is inserted into the opposing wafer holding groove, the wafer is positioned horizontally. In this state, the boat is set up in the vertical heat treatment furnace and the wafer is heat-treated.

[0003]

However, the conventional vertical heat treatment boat has a problem that slips occur on the wafer due to thermal stress during the heat treatment.

[0004]

[Discovery for Solving the Problems] The inventors of the present application have obtained the following findings. That is, the wafer holding groove of each pillar has a V-shaped cross section, and the wafer is held in point contact with the wafer holding groove at three points on the peripheral portion. Since the boat is made of high-purity quartz glass or SiC, it is very difficult to process it so that the wafer holding grooves facing each other are kept horizontal. As a result, the wafer was supported at three points without maintaining the horizontality of the wafer holding groove of each pillar. Since the wafer is tilted, the weight of the wafer itself is different at the three points on the peripheral edge of the wafer that are in contact with the wafer holding groove. Slip occurs from a contact point where the weight of the wafer itself is heavy, that is, a contact point where the weight of the wafer itself is concentrated. That is, it was found that slips do not occur if the concentration of the weight of the wafer itself is dispersed.

Therefore, an object of the present invention is to provide a boat for a vertical heat treatment furnace in which the occurrence of wafer slip is prevented.

[0006]

SUMMARY OF THE INVENTION The present invention comprises a plurality of columns, a connecting portion connecting these columns, and a wafer mounting portion arranged at the same height position of each of the columns. A boat for a vertical heat treatment furnace, wherein the wafer mounting portion has a dispersing means for dispersing the weight of the wafer when the wafer is mounted.

[0007]

In the boat for vertical heat treatment furnace according to the present invention, the dispersion means of the wafer mounting portion disperses the weight of the wafer itself when the wafer is mounted. For example, contact between the wafer mounting portion and the wafer is made into a surface contact or a line contact to prevent concentration of the weight of the wafer itself at the wafer mounting portion due to point contact. As a result, in the wafer mounting portion, no slip occurs on the wafer itself due to thermal stress during heat treatment.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 6 show a first embodiment of a boat for a vertical heat treatment furnace according to the present invention. As shown in FIGS. 3 to 5, the outer shape of the boat 11 made of high-purity quartz glass is formed into a generally cylindrical shape as a whole. The boat 11 includes a circular lower support plate 12 which is held horizontally in a vertical heat treatment furnace, a plurality of legs 13 for vertically arranging the lower support plate 12, and the lower support plate 12. On the other hand, it has four vertically-supported columns 14 and a circular upper connection plate 15 that connects the upper ends of these columns 14 together.

As shown in FIG. 4, these four columns 14 are arranged in line symmetrical positions with respect to the circular upper connecting plate 15 within a range of approximately 180 degrees in the circumferential direction. The portion of the boat 11 opposite to the portion where the columns 14 are arranged constitutes an opening for loading and unloading the wafer W having a diameter of 8 inches. As shown in FIG. 4, a rod 16 is attached to this opening to prevent the wafer W from dropping during heat treatment in a vertical heat treatment furnace after the wafer W is inserted. Reference numeral 17 in FIG. 3 is an insertion groove of the rod 16,
Indicates the insertion hole of this rod, respectively.

Further, as shown in FIGS. 1 and 2, the columns 14 are arranged at predetermined intervals along the axial direction of the columns.
A plurality of wafer holding plates 21 are welded in the horizontal direction. These wafer holding plates 21 have a semi-ring shape with a hollowed central portion, and are made of high-purity quartz glass. That is, this wafer holding plate 21
Is a substantially C-shaped shape having a predetermined thickness. The wafer W is placed on the upper surface of the wafer holding plate 21 in surface contact, so that the wafer W is held in a horizontal plane. The inner diameter of the wafer holding plate 21 is smaller than the outer diameter of the wafer W to be held. The thickness of each wafer holding plate 21 is formed so that the distance between the upper and lower wafers W is maintained at 4 mm or more.

Further, instead of the wafer holding plate 21, a wafer holding plate 22 shown in FIG. 6 may be used. The wafer holding plate 22 is such that the upper surface of the wafer holding plate 22 is inclined upward by a few degrees with respect to the horizontal plane so that the wafer holding plate 22 makes a line contact with the wafer W. In other words, the cross section of the wafer holding plate 22 of the cord has a substantially wedge shape, and
The inner peripheral edge portion is formed thicker than the outer peripheral edge that is the end fixed to the.

Then, the wafer W was loaded on the vertical heat treatment furnace boat 11 and subjected to heat treatment at a predetermined temperature for a predetermined time. As a result, no slip occurred on the wafer W. This is because the wafer W is supported in a wide range of surface contact or line contact, and the weight of the wafer W can be dispersed and supported. In order to prevent the wafer W from slipping, the upper surface of the wafer holding plate 21 may be formed in an uneven shape by sandblasting or the like. Alternatively, the wafer holding plate 21 may be tilted and fixed to the column 14 to prevent the wafer W from falling. For example, the wafer holding plate 21
It may be inclined at an angle of about 1 to 5 ° with respect to the horizontal plane so that the inner side of the boat is positioned lower than the front side of the boat.

Next, a second embodiment of the vertical heat treatment furnace boat shown in FIGS. 7 to 8 will be described. As shown in these drawings, the wafer holding plate 23 according to this embodiment is a semi-circular plate, and its diameter is larger than that of the wafer W. This point is the same as the wafer holding plate 21 of the first embodiment. is there. A rectangular notch 23A is formed in the center of the semicircular plate. This notch 23A is for inserting a wafer holder for automatic wafer transfer. In this embodiment, since the contact area between the wafer W and the wafer holding plate 23 is larger than that in the first embodiment, the mounting of the wafer W can be stabilized. Other than that, the configuration and operation are the same as in the first embodiment.

Next, a third embodiment of the present invention shown in FIG. 9 will be described. As shown in this figure, in this embodiment, the wafer holding plate 24 is disk-shaped and its diameter is the first.
This is the same as the wafer holding plate 21 of the embodiment. A rectangular notch 24A is also formed in a part of the wafer holding plate 24. A wafer holder for automatic wafer transfer is inserted into the notch 24A. The cutout 24A is longer than the cutout 23A. In this embodiment, the contact area between the wafer W and the wafer holding plate 24 is larger than that in the second embodiment, so that the mounting of the wafer W is more stable. Other than that, the configuration and operation are the same as in the first embodiment.

[0016]

As described above, according to the present invention, the occurrence of wafer slip can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a wafer holding plate holding a wafer according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a wafer holding plate holding a wafer according to the first embodiment of the present invention.

FIG. 3 is a front view showing the boat according to the first embodiment of the present invention.

FIG. 4 is a side view showing the boat according to the first embodiment of the present invention.

FIG. 5 is a plan view showing the boat according to the first embodiment of the present invention.

FIG. 6 is a vertical cross-sectional view showing a wafer holding plate holding a wafer according to the first embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a wafer holding plate holding a wafer according to a second embodiment of the present invention.

FIG. 8 is a vertical cross-sectional view showing a wafer holding plate holding a wafer according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a wafer holding plate holding a wafer according to a third embodiment of the present invention.

[Explanation of symbols]

 11 Boat 12 Lower Support Plate 14 Boat Support 15 Upper Connection Plate 21, 22, 23, 24 Wafer Holding Plate (Dispersing Means) W Wafer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoji Nagasako 3-8-16 Iwamotocho, Chiyoda-ku, Tokyo Sanryo Material Silicon Co., Ltd.

Claims (1)

[Claims] 1. A boat for a vertical heat treatment furnace, comprising a plurality of columns, a connecting portion connecting these columns, and a wafer mounting portion arranged at the same height position of each column. A boat for a vertical heat treatment furnace, wherein the wafer mounting section has a dispersing means for dispersing the weight of the wafer when the wafer is mounted.