JPH06302533A - Vertical reactive furnace - Google Patents

Abstract

PURPOSE:To provide a high temperature furnace having a rotary part with an effective sealing device for the rotary part. CONSTITUTION:Relating to a vertical reactive furnace provided with a vertical reactive tube 1, a heater unit that covers the periphery of the reactive tube 1, a boat that holds a silicon wafer in multiple-stage manner, and a boat rotation mechanism 7 for rotating the boat, at the least, a boat rotary part and a fixed part are made of quartz, and, multiple outstanding ring-like ridges 34 are formed on the bottom side of the rotary part and seal grooves 35 into which the ring-like ridges 34 are inserted loosely are formed on the fixed part, so that the ring-like ridges 34 together with the seal grooves 35 constitute a labyrinth type air seal, for sealing between the rotary part and the fixed part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical reactor in a CVD apparatus, a diffusion apparatus or the like which is one of semiconductor manufacturing apparatuses.

[0002]

2. Description of the Related Art One of semiconductor manufacturing processes is a process of forming a thin film on the surface of a silicon wafer or diffusing impurities.

In this method, a wafer is loaded into a reaction furnace, the inside of the reaction furnace is maintained at a high temperature, and a reaction gas is further introduced into the furnace to form a thin film on the surface of a silicon wafer or diffuse impurities. .

A conventional vertical reaction tube will be described with reference to FIG.

In the figure, 1 is a reaction tube having a vertical axis, and 2 is a heater unit that covers the periphery of the reaction tube 1. A soaking tube 3 is provided between the heater unit 2 and the reaction tube 1. A boat 5 loaded with silicon wafers 4 in multiple stages is loaded into the reaction tube 1 from below. The boat 5 is erected on a boat cap 6, and the boat cap 6 is rotated by a boat. The rotating shaft 8 of the mechanism 7 is fixed, the boat rotating mechanism 7 is fixed to the boat lift 9, and the boat lift 9 is attached to a boat elevator (not shown) and can be lifted and lowered.

Further, a furnace port cover 10 is provided on the boat lift 9 so as to be vertically displaceable and rotatable.
0 can be closely attached to the furnace opening of the reaction tube 1. A seal cap 11 made of stainless steel is provided between the boat lift 9 and the furnace port lid 10, the furnace port lid 10 is closely attached to the reaction tube 1, and the reaction port 1 is hermetically closed by the furnace port lid 10. In this state, the boat rotating mechanism 7 can rotate the boat 5 around the vertical axis at a required speed.

As described above, the furnace port lid 10 of the rotary shaft 8
The penetrating portion is sealed by the seal cap 11.
As shown in FIG. 3, the seal cap 11 is configured such that a bellows ring 13 is fixed to a flange 12 and a seal ring 14 is fixed to an upper end of the bellows ring 13. Further, the furnace mouth lid 10 is provided with a seal seat 15,
A through hole is formed in the center of the seal seat 15, and the seal ring 14 is airtightly fitted in the through hole.

In the processing of the silicon wafer 4, the boat 5 loaded with the silicon wafer 4 is placed in the reaction tube 1 while the inside of the reaction tube 1 is heated to a predetermined temperature by the heater unit 2.
A thin film is formed on the surface of the silicon wafer 4 by charging the inside of the reactor, closing the furnace opening with the furnace lid 10, and introducing and discharging the reaction gas into the reaction tube 1.

As described above, the boat 5 is adapted to be rotated in the reaction tube 1 by the boat rotating mechanism 7 so that the nonuniformity of the film thickness caused by the flow of the reaction gas does not occur. It is something to do.

[0010]

As described above, since the seal cap 11 is made of stainless steel, it can be used in a device such as a diffusion device where the temperature in the furnace becomes high due to the influence of heat in the reaction furnace. It was difficult. Further, since the diffusing device uses an oxidizing gas such as oxygen and hydrochloric acid, the seal cap 1
There is also a problem in that No. 1 is oxidized by an oxidizing gas and metal-oxidizes the inside of the furnace.

In view of the above situation, the present invention aims to provide an effective rotary part sealing device for a high temperature furnace.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides a standing reaction tube, a heater unit for covering the circumference of the reaction tube, a boat for holding silicon wafers in multiple stages, and a boat rotating mechanism for rotating the boat. In a vertical reactor comprising at least, the boat rotating part and the fixed part are made of quartz, and a plurality of ring ridges are formed on the lower surface of the rotating part, and the ring ridge is formed on the fixed part. It is characterized in that a seal groove for loose fitting is formed.

[0013]

[Function] The labyrinth-type gas seal is constructed by loosely fitting the ring ridge into the seal groove, preventing the high-temperature gas in the reaction tube from leaking from the rotating portion, and the ring ridge,
Since the seal groove is also made of quartz, it does not deteriorate even if the high temperature gas in the reaction tube is an oxidative corrosive gas.

[0014]

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

In FIG. 1, the same parts as those shown in FIGS. 2 and 3 are designated by the same reference numerals, and the description thereof will be omitted.

A gear case 16 is fixed to a boat elevator lift (not shown), and a bearing housing 17 is fixed to the gear case 16. A lower rotary shaft 19 is rotatably provided in the bearing housing 17 via a bearing 18,
A lower end of the lower rotary shaft 19 is exposed inside the gear case 16, and a worm wheel 22 is fitted to the lower end.
A worm 20 rotatably provided on the gear case 16 is fitted to the worm wheel 22, and a rotation shaft 21 of the worm 20 is connected to a boat rotation motor (not shown).

A boat lift 23 is fixed to the upper end of the bearing housing 17, and a quartz furnace lid 24 is fixed to the upper surface of the boat lift 23.

A furnace opening seal 26 is provided at a portion of the furnace opening cover 24 facing the reaction tube flange 25 formed at the lower end of the reaction tube 1, and the furnace opening seal 26 is in close contact with the reaction tube flange 25 and the furnace is closed. Close the mouth airtightly. Further, the furnace port lid 24 is fixed to a base 28 by a flange retainer 27, and the flange retainer 27 has a cooling water passage 29 for cooling the furnace port seal 26. Further, a cooling water passage 30 is also formed on the boat lift 23 corresponding to the position of the furnace port seal 26.

An upper rotary shaft 31 penetrating the boat lift 23 and the furnace lid 24 is concentrically provided on the lower rotary shaft 19, and a rotary flange 32 is fitted to the upper end of the upper rotary shaft 31 to rotate the rotary shaft 32. The boat cap 6 on the flange 32
Is fixed on the board.

The boat cap 6 is made of quartz, and two rows of ridges 34 are formed in a concentric ring shape on the peripheral portion of the lower surface of the boat cap 6. A seal groove 35 is formed in a portion of the furnace lid 24 facing the protrusion 34, and the protrusion 34 is loosely fitted in the seal groove 35 to form a labyrinth packing type rotary seal portion 33.

Thus, between the boat cap 6 and the furnace port cover 24, the rotary flange 32 and the furnace port cover 24.
A slight gap is formed between the boat cap 6 and
Does not interfere with the rotation.

Next, when the boat 5 is rotated through the boat cap 6, the worm 20 is rotated through the rotation shaft 21 by a boat rotation motor (not shown), and the worm wheel 22 is moved by the worm 20. Rotated, further lower rotary shaft 19, upper rotary shaft 31
The boat 5 is rotated via the.

The rotary seal portion 33 is provided between the boat cap 6 and the furnace port lid 24 to prevent high temperature gas in the furnace from entering the boat rotating mechanism 7 side. Further, since the rotary seal portion 33 is made of quartz, it does not deteriorate even if the high temperature gas in the furnace is an oxidative or corrosive gas, and there is no metal contamination due to the oxidation of the rotary seal portion 33.

The sealing effect is further increased by supplying an inert gas to the gap of the rotary seal portion 33 and slightly increasing the positive pressure. Further, although the ridge 34 and the seal groove 35 have two rows, it goes without saying that they may have three rows or more.

[0025]

As described above, according to the present invention, it is possible to employ a boat rotating mechanism at high temperature, prevent metal contamination in the reaction furnace due to the rotary seal portion, and further to use high temperature corrosive gas. It is possible to prevent the deterioration of the rotating mechanism portion due to the intrusion of the rotating mechanism portion into the rotating mechanism portion, and to exert various excellent effects.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional vertical reactor.

FIG. 3 is a cross-sectional view showing a main part of a conventional vertical reactor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction tube 2 Heater unit 4 Silicon wafer 5 Boat 6 Boat cap 7 Boat rotation mechanism 24 Furnace mouth lid 33 Rotation seal part 34 Ridge 35 Seal groove

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiji Hosaka 2-3-13 Toranomon, Minato-ku, Tokyo Kokusai Electric Co., Ltd. (72) Inventor Hisashi Yoshida 2-3-13 Toranomon, Minato-ku, Tokyo International Electric Co., Ltd.

Claims (1)

[Claims] 1. A vertical reaction system comprising at least a standing reaction tube, a heater unit surrounding the reaction tube, a boat for holding silicon wafers in multiple stages, and a boat rotating mechanism for rotating the boat. In the furnace, the boat rotating portion and the fixed portion were made of quartz, respectively, and further, a plurality of ring ridges were formed on the lower surface of the rotating portion and a seal groove into which the ring ridge was loosely fitted was formed on the fixed portion. A vertical reactor characterized in that