JPH062681U - Vertical diffusion device - Google Patents

Abstract

(57) [Summary] [Objective] To enable the use of chlorine-based process gas in a vertical diffusion device using a pyrogenic oxidation method. In a vertical diffusion device in which the furnace opening is hermetically closed by a boat pedestal 7 on which a boat 9 is placed, a sealing member 20 is provided between a reaction tube flange 12 and a flange of the boat cap. Installed in an airtight manner, metal member 1,
The space where the surface of 7 faces is completely cut off from the inside of the furnace, and water vapor,
Alternatively, it prevents the hydrochloric acid that has reacted with water vapor from coming into contact with the surface of the metal member.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vertical diffusion device, and more particularly, to an improvement of a furnace opening.

[0002]

[Prior art]

 There is a load-lock type vertical diffusion device as one of the semiconductor manufacturing devices. The vertical diffusion device processes wafers while holding them in a boat in multiple stages at a required pitch. It is placed in a lock chamber, then charged into the furnace, and after the wafer is diffused, the boat is pulled out to an airtight load lock chamber. During the diffusion process, the furnace opening of the diffusion furnace is hermetically sealed. To be done.

An outline of a load-lock type vertical diffusion device will be described with reference to FIG.

In the figure, 1 is a base, a reaction tube 2 is erected on the base 1, and a heater 4 is provided on the base 1 through a heater base 3. The heater 4 is the reaction tube 2 The inside of the reaction tube 2 is uniformly heated. A load lock chamber 5 is provided below the base 1, and a boat elevator (not shown) is provided inside the load lock chamber 5, and a boat pedestal is provided on an elevating arm 6 of the boat elevator. 7 is provided, and the boat cap 8 is placed on the boat pedestal 7. On the boat cap 8, a boat 9 for loading wafers (not shown) in multiple stages is erected.

A process gas supply pipe 10 is connected to the upper end of the reaction tube 2, and the process gas is supplied from the upper end of the reaction pipe 2 by the process gas supply pipe 10, and the processed process gas is the reaction gas. The exhaust pipe 11 communicated with the lower end of the pipe 2 exhausts the gas.

Wafers are loaded into the boat 9 by a wafer transfer machine (not shown) in a state where the boat 9 is pulled out into the load lock chamber 5 by the boat elevator. When loading is completed, the boat elevator is loaded. Raises the boat cradle 7 and loads the boat 9 into the reaction tube 2.

In a state where the furnace opening of the reaction tube 2 is hermetically closed by the boat pedestal 7, process gas is supplied from the process gas supply tube 10 to perform wafer diffusion processing. The process gas is exhausted from the exhaust pipe 11.

As described above, the wafer is diffused in the airtight furnace (in the reaction tube 2). Therefore, in order to make the inside of the furnace airtight, O-rings are installed between the contact surface between the base 1 and the boat pedestal 7 and the contact surface between the reaction tube 2 and the base 1, respectively, as will be described later. Both contact surfaces are sealed by the O-ring.

A conventional furnace opening will be described with reference to FIGS. 3 and 4.

A flange 12 is formed at the lower end of the reaction tube 2, the flange 12 is fixed to the base 1 by a flange retainer 13, and the boat pedestal 7 on which the boat cap 8 is placed is a spring. It is adapted to be pressed against the base 1 by the elevating arm 6 via 14. O-rings 15 and 16 are provided between the flange 12 and the base 1 and between the base 1 and the boat pedestal 7, and the O-rings 15 and 16 seal the furnace opening. Then, the inside of the reaction tube 2 is made airtight.

Since the O-rings 15 and 16 are easily damaged and deteriorated by heat, a cooling water passage 17 is formed in the flange retainer 13 and a cooling water passage 18 is formed in the base 1. By circulating the cooling water through the cooling water passage, the base 1 and the flange 12 are cooled to prevent damage and deterioration of the O-rings 15 and 16.

[0012]

[Problems to be Solved by the Invention] However, in the vertical diffusion apparatus, when an oxide film is formed on the wafer surface by a pyrogenic oxidation method, since the furnace opening is cooled, steam is generated. The dripping water accumulates in the space 21 formed between the flange 12 and the cooling water passage 17. Furthermore, when chlorine gas is used as the process gas, chlorine combines with water droplets to form hydrochloric acid, which corrodes the surfaces of the metal members such as the base 1 and the boat pedestal 7. There was a problem that chlorine-based gas could not be used.

In view of the above situation, the present invention prevents the surface of the metal member from being corroded even when chlorine combines with water droplets to generate hydrochloric acid.

[0014]

[Means for Solving the Problems]

 The present invention relates to a vertical diffusion device in which the furnace opening is hermetically closed by a boat pedestal on which a boat is mounted, and a sealing member is hermetically sealed between the reaction tube flange and the boat cap flange. It is characterized by being provided.

[0015]

[Action]

 By providing the sealing member in an airtight manner, the space facing the surface of the metal member at the furnace opening is completely cut off from the inside of the furnace, and steam contacts the metal member and drops, or hydrochloric acid that reacts with the steam causes metal Prevents contact with the member surface.

[0016]

【Example】

 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 FIG. 4 are designated by the same reference numerals.

When the ring-shaped seal member 20 is fixed to the flange 19 at the lower end of the boat cap 8 and the furnace opening of the base 1 is closed by the boat pedestal 7, the seal member 20 is attached to the flange 12. Make sure that they are in airtight contact. The reaction tube 2, the boat cap 8, and the flange 12 are made of quartz, and the sealing member 20 is made of a material that is not corroded by hydrochloric acid.

With the above configuration, the seal member 20 partitions the space 21 into the reaction tube 2 inside and outside. Therefore, the gas inside the reaction tube 2 does not reach the base 1, so that the steam does not come into contact with the metal surface of the base 1 or the like to form droplets, and the hydrochloric acid generated by reacting with the water droplets causes the base to be formed. 1 is not corroded either.

Needless to say, the seal member 20 may be fixed to the lower surface of the flange 12 of the reaction tube.

[0021]

[Effect of device]

 As described above, according to the present invention, since the surface of the metal member is completely shielded from the inside of the reaction tube, the dripping water droplet does not contact with the surface of the metal member to accumulate and react with the water droplet. The generated hydrochloric acid does not contact the surface of the metal member and corrode the surface of the metal member.

[Brief description of drawings]

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

FIG. 2 is a schematic view of a vertical diffusion device.

FIG. 3 is a sectional view of a furnace opening portion of a conventional vertical diffusion device.

FIG. 4 is a cross-sectional view showing a main part of a furnace opening of the conventional example.

[Explanation of symbols]

 1 base 7 boat cradle 9 boat 12 flange 20 sealing member 21 space

Claims (1)

[Scope of utility model registration request] 1. A vertical diffusion device in which a furnace opening is hermetically closed by a boat pedestal on which a boat is mounted, and a sealing member is hermetically provided between a reaction tube flange and a flange of the boat cap. A vertical diffusion device characterized in that