JPS62269312A - Hot wall furnace - Google Patents

Abstract

PURPOSE:To simplify the replacement of a furnace core tube by a method wherein a plurality of holes, to be used for introduction of gas, are provided in the region where the semiconductor wafers of a gas introducing tube will be arranged. CONSTITUTION:A furnace core tube is formed in tripple structure, an unmovable tube 2, a reaction tube 3, and a gas introducing tube 4, whereon gas introducing holes 4a are perforated on the circumference, are provided and a reaction gas introducing hole 6 is provided on both sides of the reaction tube 3. Accordingly, the pressure of gas located between the reaction tube and the gas introducing tube can be made uniform, the gas almost in the same state can be fed from the holes of the gas introducing tube, the distribution temperature can be improved, a wide flat zone can be obtained, and 50 wafers can be treated. Accordingly, if a cleaned furnace core tube is prepared, it can be replaced immediately in case of necessity, because the furnace core tube can be attached to the furnace easily, even when a polysilicon film is adhered to the reaction tube and the gas introducing tube.

Description

[Detailed Description of the Invention] [Summary] In a Botwall furnace used in the low-pressure epitaxial growth process in the manufacturing process of semiconductor devices, the furnace core tube has a triple structure and is a fixed furnace core tube inserted into the furnace body. Hot walls are used to prevent polysilicon film from adhering to the tube, and gas is introduced from both sides of the reaction tube.

[Industrial application field]

TECHNICAL FIELD The present invention relates to hot walls used in a reduced pressure eviaxial growth process and the like in the manufacturing process of semiconductor devices.

In the low-pressure epitaxial growth process, the wafer is placed horizontally on a carbon susceptor and heat treated using induction heating or infrared lamp heating, but this is not suitable for large-volume processing, and the wafer is placed vertically using hot walls. However, with conventional furnace core tubes, temperature distribution control is difficult and processing is limited to about 5 to 6 wafers, so there is a particular need for an apparatus capable of batch processing a large number of wafers.

[Conventional technology]

In the low-pressure epitaxial growth process using a conventional hot wall furnace, as shown in FIG.
1 and exhaust from the gas exhaust port 13 to maintain the pressure inside the furnace core pipe 1 at I Torr, and hydrogen gas (11□), hydrogen chloride gas (IIc+), l-rerolled silane (S
iHC1+) gas mixture from the gas inlet 12 to the furnace core tube 1.
There were four people in the room performing the heat treatment at 1,000°C.

[Problem that the invention seeks to solve]

The problems with the low-pressure epitaxial growth process using the conventional Botwall furnace explained in Section 2 are that it is difficult to control the temperature distribution and that the number of sheets that can be processed is small, and that when the polysilicon film adheres to the wall of the furnace core tube, the film thickness increases. - It is difficult to perform stable processing because it is difficult to control the resistivity distribution.

Furthermore, if the amount of polysilicon coating increases, cleaning treatment becomes necessary, but when reinstalling the furnace core tube that has been removed from the furnace body, many steps are required to completely seal the furnace core tube to maintain a vacuum inside the furnace core tube. This requires a lot of man-hours, and if the replacement frequency increases, the seal of the furnace core tube will deteriorate.

The present invention can handle such situations by increasing the number of sheets that can be processed.
The purpose is to provide a means to prevent the polysilicon film from adhering to the wall of the furnace core tube.

[Failure to solve the problem]

The above problem can be solved by triple-layering the furnace core tube 1, a fixed tube 22, a reaction tube 3, and a gas introduction tube 4 with holes 4a for introducing gas around the tube, as shown in Fig. 1. This problem is solved by the bone-wall furnace of the present invention in which gas inlets (b) 6 are provided on both sides of the reaction tube 3.

[Effect]

That is, in the present invention, the furnace core tube is made into a triple tube, and the reaction gas is introduced from both sides between the reaction tube and the gas introduction tube.
The gas pressure between the reaction tube and the gas introduction tube becomes uniform, and the gas is supplied from the hole in the gas introduction tube in almost the same condition, resulting in good temperature distribution and a wide flat zone, making it possible to process 50 wafers. is possible.

Since a mixed gas of hydrogen gas and hydrogen chloride gas is flowed between the fixed tube and the reaction tube, almost no polysilicon film adheres to the fixed tube, so there is almost no need to remove the fixed tube from the furnace body for cleaning.

Polysilicon coatings are applied to the reaction tube and gas introduction tube, but they are easy to attach to the furnace, so if you prepare cleaned ones, you can immediately replace them when necessary.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

In the figure, a fixed tube 2 is inserted into a furnace body 1, into which a reaction tube 3 and a gas introduction tube 4 are inserted in combination.

The furnace temperature before inserting the wafers 10 is set at 400°C, and using a boat loader (not shown), wafers 1o and 50 are loaded.
The wafer bath Kent 9 with the wafers placed thereon is inserted into the gas introduction pipe 4. Gate valve 14 after inserting wafer 10
Close the gas exhaust port (b) 8 to reduce the indoor pressure, and increase the furnace temperature to 1.000'c in 20 minutes.

Holes 4a having a diameter of 1 (hn) are bored around the wafer basket 9 placement position of the gas introduction pipe 4, dividing the circumference into equal parts.

The gas inlet (b) 6 for the reaction gas is provided between the reaction tube 3 and the gas inlet tube 4 on both sides of the reaction tube 3, and epitaxial growth is performed under the following set conditions.

Inner pipe pressure－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－・－－－－－－－－
---------ITorr gas flow rate]・Reflow silane (SiHCl x)------
-14! /min Hydrogen chloride gas (HCI) -----
---------・----11/win hydrogen gas (82)
−−−−−−−−−−−−−−−−−−−−8
II /min Phosphine (PH3) (5p111
11) -------------5cc/win furnace setting temperature-----------------1-
−−−−−−−−−−−−−−−−−1−−−−・−1
, 000℃The reaction gas leaked to the outside of the reaction tube 3 is transferred to the fixed tube 2.
The polysilicon film does not adhere to the inner wall of the fixed tube 2 because it is exhausted from the gas exhaust port (a) 7 along with the following gases introduced from the gas inlet port (a) 5 between the fixed tube 2 and the reaction tube 3.

Hydrogen chloride gas (HCI) ----------
11! /min hydrogen gas (l(z) -------
--------m----------11/min [Effects of the Invention] As explained above, according to the present invention, by changing the structure of the furnace core tube, an inexpensive furnace can be produced. It is now possible to batch process an order of magnitude larger number of wafers than before, and it is very easy to replace the furnace core tube to clean the furnace core tube with the polysilicon film attached, making it industrially viable. Extremely useful.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing one embodiment of the present invention, and FIG. 2 is a side sectional view showing a conventional technique. In the figure, 1 is the furnace body, 2 is the fixed tube, 3 is the reaction tube, 4 is the gas inlet tube, 4a is the hole, 5 is the gas inlet (al), 6 is the gas inlet (b), 7 is the gas exhaust port (al, 8 is a gas exhaust port fb), 9 is a wafer basket, 10 is a wafer, 11 is a furnace core tube, 12 is a gas inlet, 13 is a gas exhaust port, 14 is a gate valve.

Claims (1)

[Claims] A fixed tube (2), a reaction tube (3) disposed within the fixed tube (2), and a gas introduction tube (4) disposed within the reaction tube (3). and gas inlet ports (b) (6) for introducing the reaction gas into both sides of the portion between the gas inlet tube (4) and the reaction tube (3).
), wherein a plurality of holes (4a) for gas introduction are provided in a region of the gas introduction pipe (4) where semiconductor wafers are arranged.