JPH07106268A - Furnace core tube - Google Patents

Abstract

PURPOSE:To prevent contamination in the inside and the outside of an equipment which is to be caused by deposition of impurities in a furnace core tube as well as their discharge as in an untreated effuluent manner. CONSTITUTION:In a furnace core tube which supplies vaporized impurities to the body 11 of a furnace core tube installed so as to stretch in the horizontal direction, and is used when impurities are diffused in or deposited on an object member loaded in the body 11 of the furnace core tube, a drip tray 12 is arranged in the bottom part of an aperture for carrying-in and carrying-out in the body 11 of the furnace core tube, and reliquefied impurities are collected. Thereby contamination in the inside and the outside of an equipment which is to be caused by deposition of impurities in the body 11 of the furnace core tube as well as their discharge as in an untreated effuluent manner is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core tube, and is preferably applied to, for example, a core tube used in an impurity diffusion furnace.

[0002]

2. Description of the Related Art In a manufacturing process of an integrated circuit device, a doping process for thermally diffusing impurities into a wafer is provided as one of wafer processing processes. Conventionally, as shown in FIG. 3, an impurity diffusion furnace 1 is composed of a core tube main body 2 made of quartz glass, a heater source 3 for heating the inside of the furnace, and a liner tube 4 made of silicon carbide.

An inlet port 5 for introducing impurities into the tube is provided at one end of the core tube main body 2. This inlet port 5 is for introducing liquid impurities for diffusing in the core tube main body 2.
This is for introducing an impurity gas obtained by bubbling POCl ₃ (phosphorus oxychloride) with an inert gas and vaporizing it into the core tube main body 2. Also, the core tube body 2
At the other end, an opening 6 for loading and unloading the wafer is provided.

An exhaust port 7 for exhausting the impurity gas introduced into the tube is provided near the opening 6 in the core tube main body 2. Since this impurity gas is harmful and adversely affects the human body, after being diffused, it is exhausted from the exhaust port 7 and treated in a harmless state, and then discharged.

A liner tube 4 is provided around the core tube main body 2 to uniformly transfer the heat generated from the heater source 3 into the core tube main body 2 and to prevent the heater source 3 made of metal from being contaminated. Has been done.

The impurity gas introduced into the core tube main body 2 through the inlet port 5 is heated by the heat generated by the heater source 3 and is inserted along the inside of the core tube main body 2 in a state of being lined up. Be spread to. At this time, the inside of the core tube body 2 is located at about 950 to 1000 degrees.

[0007]

However, since the temperature of the opening of the core tube main body is lowered due to the loading and unloading of the wafer, a part of the impurity gas is liquefied in the opening and is deposited in the vicinity of the opening, or is solidified. There was a problem of turning into.

Further, since no heater source is provided near the exhaust port and the temperature is lower than that at the position where the heater source is provided, a portion of the impurity gas is liquefied even in this vicinity and is liquefied from the core tube. There is a problem of depositing without being discharged. In addition, at the time of carrying out and carrying in, there is a problem that liquid impurities accumulated in the opening drop on the floor and contaminate the periphery of the device.

Further, since the liquid impurities remain in the core tube, there is a possibility that the characteristics of the semiconductor product may be changed due to the dispersion of the resistance value on the surface of the wafer inserted in the core tube and the removal of the deposited impurities.

The present invention has been made in consideration of the above points, and is intended to propose a reactor core tube capable of preventing the risk of contamination of the inside and outside of the apparatus due to the accumulation of impurities in the reactor core tube and the drifting of impurities. is there.

[0011]

In order to solve such a problem, in the present invention, vaporized impurities are supplied to a tubular core tube main body 11 which is attached so as to extend in the horizontal direction, and the core tube main body 11 is supplied. In the core tube 10 used when diffusing or depositing impurities in the object placed inside, collect the reliquefied impurities at the bottom of the opening 6 provided in the core tube body 11 for carrying in and out. A saucer 12 for storing the food is provided.

[0012]

When the vaporized impurities are supplied to the tubular core tube main body 11 mounted so as to extend in the horizontal direction and the impurities are diffused or accumulated in the object placed in the core tube main body 11. In the furnace core tube 10 used for, the saucer 12 is arranged at the bottom of the opening 6 provided for carrying out and carrying in the core tube main body 11, and the impurities in the core tube main body 11 are collected by collecting the reliquefied impurities. It is possible to prevent the possibility of contamination of the inside and outside of the device due to the accumulation of impurities and the running off of impurities.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, in which parts corresponding to those in FIG. 3 are designated by the same reference numerals, 10 indicates a core tube as a whole, and a tray 12 is provided in the bottom of the core tube body 11 near the opening 6 in the vicinity thereof.
It has the same structure except that it has. The core tube main body 11 is provided with a saucer 12 for collecting the liquefied impurity POCl ₃ in the lower part near the opening 6. A concave groove 13 for flowing the liquid impurities to the receiving tray 12 is provided along the bottom portion of the furnace core body 11 from the receiving tray 12 toward the inlet 5. A drain port 14 for discharging the collected liquid impurities is provided at the bottom of the tray 12.
Is provided.

In the case of this example, for example, the core tube main body 11 has a length a of 2.4 [m] and an outer diameter b of the opening 6 of 18.5 [cm]. The tray 12 provided in the core tube main body 11 has a length c
Is 12 to 13 [cm], the width d is 4 to 5 [cm], and the depth e is 1.5.
[Cm], and the length f from the end of the tray 12 to the end of the groove 13 is 1 [m].

In the above structure, the inside of the core tube main body 11 in which the wafer is set is heated by the heater source (not shown). At this time, since the impurity gas POCl ₃ introduced from the inlet 5 exists in the main body 11 of the furnace tube, it is thermally diffused into the wafer by being heated by the heater source. Further, the impurity gas after the thermal diffusion is discharged from the exhaust port 7.

After diffusion, the processed wafer is unloaded,
Then, when a new wafer is loaded, the temperature near the opening 6 is lowered and the impurity gas is liquefied. The liquid impurities adhere to the inside of the core tube main body 11, collect under the core tube main body 11 and collect in the receiving tray 12 by connecting the groove 13, and are discharged from the drain port 14 provided in the receiving tray 12.

According to the above construction, by providing the tray 12 and the groove 13 near the opening 6 of the core tube main body 11, the liquid impurity POCl ₃ is collected in the tray 12 and discharged.
Therefore, a large amount of impurities do not remain in the core tube main body 11, and these impurities do not adhere or deposit on the inner wall of the core tube main body 11. As a result, the resistance value on the surface of the wafer inserted into the core tube main body 11 can be made uniform, and the number of cleanings inside and outside the apparatus can be reduced.

In the above-mentioned embodiment, the liquid impurities are transmitted to the groove 13 and collected in the tray 12. However, the present invention is not limited to this, and instead of providing the groove 13, it is shown in FIG. As described above, the same effect can be obtained even if the core tube main body 11 is inclined at an angle of 2 to 3 so that the opening 6 becomes low.

In the above-mentioned embodiment, the liquid impurities are transmitted to the groove 13 and collected in the receiving tray 12, but the present invention is not limited to this, and in addition to providing the groove 13 and the receiving tray 12. 2 to 3 ° on the entire core tube main body 11
The same effect can be obtained even with the inclination.

Further, in the above-mentioned embodiment, the case of forming the N-type semiconductor by using the impurity POCl ₃ as the diffusion source has been described, but the present invention is not limited to this, and a gas such as B (boron) is used as the diffusion source. It is also good to use it to form a P-type semiconductor.

Further, although the impurity diffusion furnace has been described in the above embodiment, the present invention is not limited to this, and can be applied to an apparatus having a horizontally extending furnace core tube such as a horizontal decompression CVD apparatus.

[0023]

As described above, according to the present invention, the main body of the core tube is provided with the tray for collecting the reliquefied impurities. It is possible to easily realize a core tube that can reduce the risk of contamination.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a core tube according to an embodiment of the present invention.

FIG. 2 is a perspective view showing another impurity diffusion furnace.

FIG. 3 is a perspective view showing a conventional impurity diffusion furnace.

[Explanation of symbols]

1 ... Impurity diffusion furnace, 2, 11 ... Core tube main body, 3 ...
Heater source, 4 ... Liner tube, 5 ... Inlet, 6
…… Aperture, 7 …… Exhaust port, 10 …… Core tube, 12 ……
Receptacle, 13 ... Groove, 14 ... Drainage port.

Claims (4)

[Claims] 1. A vaporized impurity is supplied to a tubular core tube main body which is attached so as to extend in the horizontal direction, and the impurity is diffused or deposited on an object placed in the core core tube main body. In the core tube used at that time, the core tube is provided with a saucer for collecting reliquefied impurities at a bottom portion of an opening provided for carrying out and carrying in the core tube main body. 2. The core tube according to claim 1, further comprising a groove extending from the tray in a direction opposite to the opening along a bottom portion of the core tube main body. 3. The core tube according to claim 1, wherein the core tube main body is arranged with an inclination so that the opening side is lower than the opposite side. 4. The core tube according to claim 1, further comprising a discharge portion for discharging the collected liquid at the bottom of the tray.