JP2550059B2 - Heat treatment equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat treatment apparatus provided with a process tube for heat treating a semiconductor wafer, and more particularly to preventing entrapment of atmospheric air from the opening of the process tube. The present invention relates to a heat treatment apparatus that prevents the formation of a natural oxide film.

[Conventional technology]

In general, when performing processing such as epitaxial growth and CVD of a semiconductor wafer, an apparatus is used in which the semiconductor wafer is inserted into a process tube whose inside is kept in a desired gas atmosphere to perform heat treatment.

In recent years, in this type of heat treatment apparatus, various apparatuses have been proposed in order to automate the loading / unloading of a semiconductor wafer into / from a process tube.
Japanese Patent Laid-Open No. 111758 describes a configuration in which a boat in which a plurality of semiconductor wafers are arranged in an array is put in and taken out by a drawing rod that is operated outside the opening of a process tube.

A soft landing device has been conventionally proposed for loading and unloading the semiconductor wafer. By mounting the semiconductor wafer on the tip of a fork and finely controlling the forward and backward movement and vertical movement of the fork, the semiconductor wafer Optimized loading and unloading.

[Problems to be solved by the invention]

In this way, various improvements have been made in putting the semiconductor wafer in and out of the process tube, but in any of the methods, it is necessary to always perform work with the opening of the process tube opened when taking the semiconductor wafer in and out. is there. For this reason, at the time of this loading and unloading, atmospheric air is introduced into the interior from the process tube opening, so-called atmospheric air entrapment occurs, the atmospheric air is mixed with the required gas in the process tube, and a natural oxide film is formed on the surface of the semiconductor wafer. Suitable heat treatment cannot be performed.

For this reason, conventionally, the step of expelling the atmosphere after inserting the semiconductor wafer into the process tube has been indispensable, which causes a problem that the number of working steps increases and the processing becomes complicated.

An object of the present invention is to provide a heat treatment apparatus which prevents the entrainment of air into the process tube and optimizes the heat treatment.

[Means for solving problems]

In the heat treatment apparatus of the present invention, a pair of opposed opening / closing doors are arranged in front of the opening of the process tube, and the fork is provided with an inner cap that closes the inside of the fork and an outer cap that is fitted to the outside. The opening / closing door has a substantially semicircular notch corresponding to the outer circumference of the fork and is configured to be in contact with the outer cap.

[Action]

The contact between the open / close door and the outer cap makes it possible to close the open end of the process tube and the fork, and even when the fork moves downward with respect to the process tube, this closed state can be maintained. It is possible to prevent the air from getting into the atmosphere and set the inside of the tube to a predetermined gas atmosphere, which makes it possible to optimize the heat treatment and improve the treatment efficiency.

〔Example〕

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

FIG. 1 is a perspective view of an essential part of the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a schematic side sectional view of the entire structure.

In these figures, 1 is a process tube,
The semiconductor wafer set in the heating furnace H and inserted therein can be heat-treated. In this process tube 1, the tip 1a has a small diameter, and a desired reaction gas can be supplied into the tube 1 from here. Further, the front end portion 1b is opened as an opening portion as it is, and the semiconductor wafer can be put in and taken out from here. Further, in this embodiment, a large-diameter cylinder 2 is fixed around the opening of the process tube 1 to make it possible to introduce nitrogen gas into a space 3 defined by a double cylinder structure. A plurality of through holes 4 are opened in the process tube 1 of a part so that the nitrogen gas is ejected in a shower shape.

A pair of open / close doors 5 and 6 which are supported by hinges 5a and 6a on an apparatus fixing portion (not shown) and whose tips are vertically opened and closed are provided in front of the opening 1b of the process tube 1. It is arranged. These opening / closing doors 5 and 6 have semicircular cutouts 5b and 6b formed at the respective leading edges thereof in the vertical direction, which are somewhat longer than the forks 7 described later.

On the other hand, a fork 7 for loading and unloading the semiconductor wafer W to be heat-treated into and out of the process tube 1 is fixedly supported at a base end thereof to a part 8 of a known soft landing device,
It is possible to move back and forth and up and down. The fork 7 can mount a boat 9 on which a plurality of semiconductor wafers W are mounted on a fork portion 7a at the tip.

Further, at the base end position of the fork portion 7a of the fork 7, an inner cap 10 for closing the tubular inside of the fork 7 is provided.
A circular outer cap 11 is fitted and attached to the outer side of the fork 7 so as to be movable in the cylinder axis direction of the fork 7. The outer cap 11 has a hole 12 having a diameter substantially equal to that of the fork 7 at a position eccentric to the lower side, and the fork 7 is inserted into this hole.

According to this configuration, in the state shown in FIG. 3, the fork 7 has the semiconductor wafer W mounted on the fork portion 7a by the boat 9 and is moved forward by the soft landing device. At this time, in the process tube 1, while supplying the processing gas from the tip 1a, the nitrogen gas is ejected from the through hole 4 at the opening end to form the nitrogen gas shower,
We are trying to prevent the invasion of the atmosphere into the interior. At this time, the open / close doors 5 and 6 are open.

Next, in the state in which the fork 7 has entered the process tube 1, the opening / closing doors 5 and 6 are closed and the outer cap 11
Contact the outer surface of. As a result, the outer cap 11 closes the open end of the process tube 1. Therefore, it is possible to suppress the entrapment of the atmosphere in the process tube 1. During this period, the shower of nitrogen gas is continued, further suppressing air entrainment. At this time, the gap between the upper opening / closing door 5 and the fork 7 is held at the minute gap x.

Then, as shown in FIG. 5, when the fork 7 is further advanced, the outer cap 11 and the fork 7 are inserted into the process tube 1. At this time, the open end of the process tube 1 is maintained by the outer peripheries of the opening / closing doors 5 and 6 and the fork 7.

Then, as shown in FIG. 6, when the fork 7 is moved downward by the soft landing device to place the boat 9 in the process tube 1, the lower opening / closing door 6 is opened to move the fork 7 downward. It is possible. Then, when the fork 7 moves backward with the downward motion and the outer cap 11 is moved to the opening end position of the process tube 1, the opening end is closed by the upper opening / closing door 5 and the outer cap 11. It retains the occluding effect inside the tube.

From this state, the heat treatment for the semiconductor wafer is performed as usual.

Therefore, in this apparatus, the opening / closing doors 5 and 6 and the outer cap 11 cooperate to hold the opening of the process tube 1 in a closed state when the semiconductor wafer W is taken in and out, thereby effectively preventing the atmospheric air from being trapped in the tube. it can. As a result, the inside of the process tube 1 can be immediately set to a predetermined gas atmosphere, and rapid heat treatment and prevention of formation of a natural oxide film can be realized.

Further, the semiconductor wafer after the processing can be taken out by a process which is substantially the reverse of the process described above.

〔The invention's effect〕

As described above, according to the present invention, a pair of opposing opening / closing doors are arranged at the front position of the opening of the process tube, and the fork has an inner cap that closes the inside of the fork and an outer cap that fits on the outside. Since the opening / closing door is provided with a substantially semicircular notch corresponding to the outer circumference of the fork and can be contacted with the outer cap, the opening / closing door and the outer cap are brought into contact with each other so that the opening end of the process tube and the fork are Can be closed, and even when the fork moves downward relative to the process tube, this closed state can be maintained, which prevents the process tube from being entrained in the atmosphere and creates a predetermined gas atmosphere inside the tube. It can be set, and heat treatment can be optimized and treatment efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part of an embodiment of the present invention, FIG. 2 is a schematic view seen from the front thereof, FIG. 3 is a schematic side sectional view showing the entire structure, and FIGS. FIG. 4 is a side sectional view similar to FIG. 3 for explaining the operation. 1 ... Process tube, 2 ... Large diameter tube, 3 ... Space,
4 ... Through hole, 5,6 ... Open / close door, 1 ... Fork, 8 ...
Soft landing device, 9 ... Boat, 10 ... Inner cap, 11 ... Outer cap, 12 ... Hole, W ... Semiconductor wafer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Tetsuya Kishida Tetsuya Kishida 3681 Hayano, Mobara-shi Hitachi Device Engineering Co., Ltd. (56) Reference JP-A-56-248126 (JP, A)

Claims (1)

(57) [Claims] 1. A heat treatment apparatus having a process tube for heat-treating a semiconductor wafer inserted and set inside from an opening end, and a fork for inserting the semiconductor wafer into the process tube, wherein a front position of the opening of the process tube is provided. A pair of vertically openable doors are arranged in the fork, and the fork has an inner cap that closes the inside of the fork.
An outer cap that fits on the outer side of the fork is provided, and the opening / closing door has a substantially semicircular cutout corresponding to the outer periphery of the fork and is configured to be contactable with the outer cap.