JPH08316158A - Semiconductor wafer boat - Google Patents

Abstract

PURPOSE: To provide a semiconductor wafer boat, wherein dummy wafers, whose thicknesses become thicker stepwise toward upper and lower supporting plates, are mounted on both upper and lower side parts of the semiconductor wafer boat so that the drastic temperature change does not affect the semiconductor wafer. CONSTITUTION: In a semiconductor wafer boat 40 in which semiconductor wafers to be heat-treated are placed, an upper supporting plate 41 and a lower supporting plate 42 and a plurality of supporting posts 43, whose upper and lower end parts are fixed to the upper supporting plate 41 and the lower supporting plate 42 by a means such as welding, adhesion or the like, are provided. Then, the following parts are contained at the intermediate parts of the supporting posts 43. Semiconductor-wafer inserting grooves 44 are formed at regular intervals for placing the semiconductor wafers 1. Dummy-wafer inserting grooves 45 and 46 are formed so that each groove width becomes wider stepwise from both end part of the semiconductor-wafer inserting groove 44 toward the upper supporting plate 41 and the lower supporting plate 42 at both upper and lower end parts of the supporting post 43.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer boat used in a heat treatment process of a semiconductor wafer,
In particular, the present invention relates to a semiconductor wafer boat for uniformly processing a large number of semiconductor wafers in a heat treatment furnace.

[0002]

2. Description of the Related Art In the manufacture of semiconductor wafers, heat treatment of semiconductor wafers is carried out for treatments such as oxidation and diffusion. In the heat treatment of this semiconductor wafer, first, the semiconductor wafer is placed in the semiconductor wafer insertion grooves formed at equal intervals in the semiconductor wafer boat made of quartz or silicon carbide, and the semiconductor wafer boat is mounted. The fuel gas (for example, hydrogen gas) and oxygen gas are supplied from the outside to a combustion apparatus installed in the vertical or horizontal heat treatment furnace to burn them, and the combustion gas generated thereby ( For example, water vapor is supplied to the semiconductor wafer.

By the way, the thickness of the semiconductor wafer is about 60.
It is as thin as 0 μm and its heat capacity is small. Therefore, when the semiconductor wafer is placed in the semiconductor wafer insertion groove of the semiconductor wafer boat and is put in and out of the furnace, a sudden temperature change at the time of putting in and out of the furnace causes a semiconductor wafer boat. Occurs on the semiconductor wafer placed on the semiconductor wafer, especially on the semiconductor wafers at the upper and lower ends of the semiconductor wafer boat, and as a result, the semiconductor wafer is cracked or slips to reduce the yield of products. There was an occasion.

Therefore, in recent years, in order to improve the above-mentioned problems, as shown in FIG. 3, an intermediate portion of a semiconductor wafer boat 50 including an upper support plate 51, a lower support plate 52, and a plurality of columns 53. A large number of semiconductor wafers 55 to be heat treated are placed at equal intervals, and
Both ends of the semiconductor wafer board 50 (upper end side,
Several sheets of so-called dummy wafers 56 having the same material and the same shape and dimensions as those of the semiconductor wafer 55 are provided at the lower end portion.
Dozens of them are placed and heat treatment is performed. That is, abrupt temperature changes occurring at both ends of the semiconductor wafer boat 50 are prevented from directly affecting the semiconductor wafer 55 placed in the middle portion, and cracks and slips of the semiconductor wafer 55 are prevented. It is what

[0005]

However, as described above, dummy wafers are formed on both ends of the semiconductor wafer.
Even when the wafer is placed so that a sudden temperature change does not act, since the dummy wafer is made of the same material and has the same shape and dimension as the semiconductor wafer, the dummy wafer has the same heat capacity as the semiconductor wafer. Small, abrupt temperature changes affect the semiconductor wafers located at both ends (upper end and lower end) of the semiconductor wafer arranged in the middle part, and the semiconductor wafer is cracked or slips. May occur.

In order to solve this, a considerable number of dummy wafers are placed, and the semiconductor wafer boat is put in a furnace.
It is sufficient to prevent the sudden temperature change during the furnace removal from affecting the semiconductor wafer.However, if a considerable number of dummy wafers are placed on the semiconductor wafer boat, the number of heat-treated semiconductor wafers will be significantly increased. However, there was a problem that productivity was drastically reduced.

The present invention has been made in order to solve the above-mentioned technical problems, and the thickness of the semiconductor wafer boat is gradually increased toward the upper and lower support plates on both upper and lower sides thereof. An object of the present invention is to provide a semiconductor wafer boat on which a dummy wafer is placed so that a sudden temperature change does not affect the semiconductor wafer.

[0008]

In order to achieve the above object, a semiconductor wafer boat according to the present invention is provided with an upper support plate and a lower support in a semiconductor wafer boat on which a semiconductor wafer to be heat treated is placed. A plate, a plurality of support posts whose upper and lower end portions are integrally fixed to the upper support plate and the lower support plate by means of welding, adhesion, etc., and for mounting a semiconductor wafer on an intermediate portion of the support columns. The semiconductor wafer insertion grooves formed at equal intervals, and the semiconductor wafer at the upper and lower sides of the pillar.
The dummy wafer insertion groove is formed so that the groove width is gradually increased from both ends of the wafer insertion groove toward the upper support plate and the lower support plate of the semiconductor wafer boat.

[0009]

With such a structure, in the semiconductor wafer boat according to the present invention, the semiconductor wafer to be heat-treated
Place the ha in the middle of the semiconductor wafer boat,
A dummy wafer whose thickness gradually increases in a groove formed so as to gradually widen from the both ends of the mounted semiconductor wafer toward the upper support plate and the lower support plate of the semiconductor wafer boat. Since the semiconductor wafer is mounted, the heat capacity of the dummy wafer can be increased as it is closer to both ends (upper and lower support plates) of the semiconductor wafer boat.

Therefore, when heat-treating a semiconductor wafer, a rapid temperature change during the loading and unloading of the semiconductor wafer boat directly affects the semiconductor wafer mounted in the middle part of the semiconductor wafer boat. Instead, the semiconductor wafer is heated and cooled with a gentle temperature gradient, so that the temperature change of the semiconductor wafer is made uniform and cracks and slips can be prevented from occurring.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a front view showing a semiconductor wafer boat according to the present invention, and FIG. 2 is a vertical sectional view showing the structure of a vertical heat treatment furnace for heat-treating a semiconductor wafer.

In the figure, a vertical heat treatment furnace 20 has a furnace core tube device 21 for simultaneously processing a large number of semiconductor wafers 1 to be heat-treated, as shown in, for example, Japanese Unexamined Patent Publication No. 2-273918. A soaking tube 22 arranged to maintain an appropriate space around the furnace core tube device 21 to secure a soaking area, and a heating member 23 arranged around the soaking tube 22. An adiabatic pipe 24 arranged around the heating member 23, a housing 25 for holding the furnace core tube device 21, and an opening of the furnace core tube body 21a in which the furnace core tube device 21 is included. And a furnace lid 26 having a furnace lid body 26a that directly abuts against the end portion.

In the furnace core tube device 21, a furnace core tube main body 21a for heat-treating the semiconductor wafer 1 in a soaking region formed in the internal space, and a fuel gas such as hydrogen and an oxygen gas are internally provided. A gas supply pipe 27a for supplying each,
27b, a combustor 28 for combusting a fuel gas to generate a combustion gas, and the combustion gas generated by the combustor 28 as a processing gas for a semiconductor wafer.
A combustion gas supply pipe 29 for supplying the internal space from the top of a and a gas discharge pipe 30 for discharging the used combustion gas to the outside are provided.

A heat insulating cylinder 31 is arranged on the upper surface of the furnace lid main body 26a in the furnace core tube main body 21a, and a large number of semiconductor wafers to be heat-treated on the upper surface of the heat insulating cylinder 31 are provided. A semiconductor wafer boat 40 on which 1 is mounted is installed. Then, the heat retaining cylinder 31
The semiconductor wafer boat 40 installed above moves integrally from the driving device (not shown) through the driving member 33 with the furnace lid moving member to carry out furnace loading / unloading, and The semiconductor wafer 1 is configured to be heat-treated in the furnace core tube device 21.

Next, the semiconductor wafer boat 40 will be described in detail with reference to FIG. As shown in the figure, the semiconductor wafer boat 40 is made of quartz or silicon carbide, and has an upper support plate 41, a lower support plate 42,
And a plurality of columns 43. The upper support plate 41 and the lower support plate 42 have semi-circular sides (180
The upper and lower ends of the columns 43 arranged at equal intervals (corresponding to the degree) are integrally fixed by means such as welding or adhesion. A plurality of wafer insertion grooves 44 for horizontally mounting the semiconductor wafer 1 to be heat-treated are formed at equal intervals in the vertical direction on the intermediate portion of the plurality of columns 43. .

Further, from the upper and lower end portions of the wafer insertion groove 44 to the upper and lower end portions of the support column 43 (semiconductor wafer boat 4
0 of the upper and lower side supporting pre - Damiue stepwise groove width toward the bets 41, 42) widens - Ha insertion groove 45 _-1, 45 _-2
... 45 _-n and 46 _-1 , 46 _-2 ... 46 _-n are formed at equal intervals. The Damiue - Ha insertion groove 45 _-1, 45 _-2 ··· 45 _-n and 46 _-1, 46 _-2 ·
.. 46 _-n are dummy wafers 2 _-1 , 2 _-2 whose thickness gradually increases from the same thickness as the semiconductor wafer to be heat-treated
... for mounting 2 _-n in a horizontal state.
In addition, dummy wafer insertion grooves 45 _-1 and 46 _-1 , 45 _-2 and 4
6 _-2 , ... 45 _-n and 46 _-n have the same groove width,
A dummy wafer having the same thickness can be placed.

Next, the occurrence of slip when heat-treated using a semiconductor wafer having a diameter of 6 inches and a thickness of 600 μm will be described. First, as an example, 100 semiconductor wafers are placed horizontally in a wafer insertion groove 44 formed with a groove width of 700 μm and a groove pitch of 5 mm at an intermediate portion of the semiconductor wafer boat 40. .

Further, the semiconductor weather - Damiue of Haboto 40 - Ha insertion groove 45 _-1, 45 _-2 ··· 45 _-n and 46
_-1 , 46 _-2 ... 46 _-n have groove widths of 700 μm, 800 μm ... 1600 μm from the end of the semiconductor wafer insertion groove 44 toward the upper and lower support plates 41, 42, respectively.
And the dummy wafer insertion grooves 45 _-1 , 45 _-2 ... 45 _-10 and 46.
_-1 , 46 _-2 ... 46 _-10 with a thickness of 600 μm, 700
10 dummy wafers 2 ₋₁ , 2 _-2・ ・ ・ 2 _-10 , which gradually increase in thickness by 100 μm and 1500 μm
Was placed. This relationship is shown in Table 1 below.

[0019]

[Table 1]

As is clear from Table 1, the thickness of the dummy wafer 2 is gradually reduced from the furnace inner side (upper support plate side) of the furnace core tube body 21a, and the tenth dummy wafer 2 is obtained.
The wafer 2 has the same thickness as the semiconductor wafer 1, and subsequently 100 semiconductor wafers 1 are placed, and then the dummy wafer 2
The thickness is gradually increased toward the furnace port side (lower support plate side) of the furnace core body 21a.

The furnace temperature is 800. C, the furnace introduction speed is 5 cm / min, and the furnace discharge temperature is 800. C, the furnace removal rate is 2 cm / min, and the heat treatment temperature is 1150. Heat treatment was performed for 2 hours at C.

As a comparative example, ten dummy wafers 2 having the same shape and dimensions (diameter 6 inches, thickness 600 μm) as the semiconductor wafer 1 are placed on the upper and lower sides, respectively, and the semiconductor wafer is the same as the embodiment. 100 pieces of C1 were placed and heat-treated under the same heat-treatment conditions. The results are shown in Table 2. still,
In the table below, the semiconductor wafers are shown as the first, second, and 100th semiconductor wafers from the upper support plate side, and the lengths of the slips generated in the respective semiconductor wafers are displayed and the occurrence of the slips is also shown. When no was observed, it was displayed as “none”.

[0023]

[Table 2]

As shown in Table 2 above, in this embodiment, neither cracks nor slips were found at both ends of the semiconductor wafer 1. On the other hand, in the comparative example, three to four semiconductor wafers 1 close to the upper and lower support plates are used.
Occurrence of slip was observed in the. That is, in the embodiment, when the semiconductor wafer boat 40 is charged into the furnace, a dummy wafer having a large heat capacity on the furnace back side (upper support plate side).
Since it is heated by the wafer 2, the inside of the semiconductor wafer boat 40
The temperature change of the semiconductor wafer 1 can be made more uniform, and a rapid temperature rise of the semiconductor wafer 1 itself can be prevented.

Further, at the time of unloading the furnace, cooling starts from the thicker dummy wafer 2, but since the heat capacity of the dummy wafer 2 changes stepwise, the semiconductor wafer in the semiconductor wafer boat 40 is changed. The cooling temperature of the wafer 1 can be made uniform, and rapid cooling of the semiconductor wafer can be prevented. Therefore, it is possible to prevent a rapid temperature change of the semiconductor wafer 1, and it is possible to prevent cracks and slips due to this.

In the embodiment according to the present invention, the thickness of the dummy wafer, the amount of change in thickness, the number of used wafers, the mounting interval of the dummy wafers, etc. are set to the semiconductor wafer to be heat-treated.
It depends on the temperature of the wafer and the semiconductor wafer boat when the boat is put in and out of the furnace, and the heat treatment conditions can be set appropriately depending on the semiconductor wafer. Further, in the embodiment of the present invention, the case of using the vertical heat treatment furnace for heat-treating a semiconductor wafer having a diameter of 6 inches or more has been described with the increase in diameter of the semiconductor wafer. However, the present invention can be applied to a horizontal heat treatment furnace for heat treating a semiconductor wafer having a diameter of 6 inches or less.

[0027]

As described above in detail, in the semiconductor wafer boat according to the present invention, the upper and lower end portions of the upper and lower support plates are integrally fixed to each other by means of welding, bonding, etc. Semiconductor wafer insertion grooves are formed at equal intervals for mounting the semiconductor wafer on the upper part, and the upper and lower sides of the semiconductor wafer insertion groove are located above and below the semiconductor wafer insertion groove on both upper and lower sides of the pillar. The dummy wafer insertion groove is formed so that the groove width gradually increases toward the support plate and the lower support plate, and the dummy wafer whose thickness gradually increases is placed in the dummy wafer insertion groove. The heat capacity of the dummy wafer may be increased as it gets closer to the upper and lower support plates, and the heat capacity may be made smaller as it gets closer to both ends of the semiconductor wafer to be heat-treated. Kill.

Therefore, the semiconductor wafer according to the present invention
In the boat, the rapid temperature change during the loading and unloading of the wafer boat does not directly affect the semiconductor wafer,
Since the semiconductor wafer is heated / cooled with a gentle temperature gradient, the temperature change of the semiconductor wafer subjected to the heat treatment is made uniform, and it is possible to prevent the occurrence of cracks and slips. .

[Brief description of drawings]

FIG. 1 is a front view showing a semiconductor wafer boat according to the present invention.

FIG. 2 is a vertical cross-sectional view showing the configuration of a vertical heat treatment furnace for heat-treating a semiconductor wafer.

FIG. 3 is a front view showing a semiconductor wafer boat having a conventional structure.

[Explanation of symbols]

 1 Semiconductor Wafer 20 Vertical Heat Treatment Furnace 21 Furnace Core Tube Device 40 Semiconductor Wafer Boat 41 Upper Support Plate 42 Lower Support Plate 43 Strut 44 Wafer Insertion Groove 45-n Dummy Wafer Insertion Groove 46-n Dummy Wafer Insertion groove

Claims (1)

[Claims] 1. A semiconductor wafer boat on which a semiconductor wafer to be heat-treated is mounted, wherein an upper support plate and a lower support plate and upper and lower end portions of the upper support plate and the lower support plate are welded or bonded. A plurality of stanchions integrally fixed by means, semiconductor wafer insertion grooves formed at equal intervals for mounting a semiconductor wafer in the middle of the stanchions, and upper and lower sides of the stanchion. A dummy wafer insertion groove formed so that the groove width gradually increases from both ends of the semiconductor wafer insertion groove toward the upper support plate and the lower support plate of the semiconductor wafer boat. Semiconductor wafer boat.