JPH06349752A - Vertical diffusion furnace - Google Patents

Abstract

PURPOSE:To form uniform films by eliminating differences in heating and holding time among numerous semiconductor substrates. CONSTITUTION:The title furnace is provided with a furnace tube 1 which can house numerous semiconductor substrates 7 in its length direction in a furnace body 2. The furnace tube 2 has an opening/closing opening 6 so that the substrates 7 can be put in and taken out from the tube 1 from the front side of the furnace body 2. Especially, door sections 3 and 4 are installed to the furnace body 2 so that the opening 6 can be formed when the sections 3 and 4 are opened. The substrates 7 are horizontally brought nearer or separated farther from the furnace body 2 while they are vertically arranged on a boat 8 in front of the furnace body 2 at the time of putting or taking out the substrates 7 in or from the furnace body 2. Therefore, the heating time of the substrates 7 becomes even irrespective of their positions, whether they are at the top or bottom of the vertical row, and uniform films can be formed on the substrates 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical diffusion furnace for uniformly forming a thin film on a semiconductor substrate.

[0002]

2. Description of the Related Art A vertical diffusion furnace is used in a process of manufacturing a semiconductor device, particularly in a process of forming an oxide film, a nitride film and the like on a semiconductor substrate. A conventional vertical diffusion furnace is composed of a furnace core tube around which a heater is wound, and the furnace core tube is arranged in the vertical direction. The inside of the furnace core tube can accommodate a large number of semiconductor substrates. On the other hand, the semiconductor substrates to be deposited are arranged in rows in a predetermined boat, and the openings provided in the lower part of the furnace core tube. It is inserted into the furnace core tube through.

When inserting the boat in which the semiconductor substrates are arranged in a row as described above into the furnace core tube, the boat is raised at a low speed (about 10 cm / min) by using an elevator mechanism. Then, the semiconductor substrate is set at a predetermined position in the furnace core tube, and a predetermined film forming process is performed on the set semiconductor substrate. Then, after the preset film formation time has elapsed, the elevator mechanism operates to lower the boat in which the semiconductor substrates are arranged in a row at the same low speed as above. As a result, a large number of semiconductor substrates are taken out from the furnace core tube, and thus a series of film forming steps is completed. In the above case, the heater around the furnace core tube is always in the heating state (8) in order to eliminate the time loss required for raising or lowering the temperature of the furnace core tube.
The temperature is maintained at 100 to 900 ° C.

[0004]

By the way, when the semiconductor substrates are arranged in rows in the boat as described above, for example, 134 semiconductor substrates are arranged in the vertical direction in a stacked state, and the length thereof is 80 to 90 cm. Reach On the other hand, the moving speed of the boat that moves up and down by the elevator mechanism is as slow as about 10 cm / min as described above. In order to load and unload semiconductor substrates arranged in a row in this way at a low speed from the furnace core tube, among the plurality of semiconductor substrates on the boat, especially the uppermost one and the lowermost one, the heating and holding time There are significant differences.

That is, for example, the uppermost semiconductor substrate is heated most quickly when the boat is inserted into the furnace core tube, and is heated to the end when the boat is taken out from the furnace core tube. On the other hand, the lowermost semiconductor substrate starts to be heated most slowly, and is taken out from the furnace core tube earliest. As a result, there is a problem in that the film thickness and the like after film formation vary particularly between the uppermost semiconductor substrate and the lowermost semiconductor substrate of the boat.

Therefore, an object of the present invention is to provide a vertical diffusion furnace capable of realizing uniform film formation by eliminating the difference in heating and holding time among a large number of semiconductor substrates.

[0007]

A vertical diffusion furnace according to the present invention comprises a furnace core tube capable of accommodating a large number of semiconductor substrates in a longitudinal direction in a furnace body. An opening / closing type opening is provided so that the semiconductor substrate can be inserted and removed from the front surface of the furnace body.

In particular, the present invention has a door portion that can be opened and closed in the furnace body, and the opening portion is formed by opening and closing the door portion.

[0009]

According to the present invention, an opening is provided on the front surface of the furnace body,
In addition, this opening is formed by opening and closing the door part that is provided so as to be openable and closable in the furnace body.By providing such an opening, boats with semiconductor substrates arranged in a row can be inserted and removed from the front of the furnace body. To do. And a boat with semiconductor substrates arranged in a row
Through the opening, the vertical diffusion furnace is inserted into the furnace core tube from the front to the inside. During this boat insertion, the furnace body is in a heated state, and the heating process is started at the same time when the boat is inserted. After the insertion of the semiconductor substrate is completed, the opening is automatically closed and the predetermined heat treatment is continued.

When the required heating and holding time in the film forming process elapses, the above-mentioned opening is formed, and in this state, the boats in which the semiconductor substrates are arranged are moved to the front and separated from the furnace core tube, The semiconductor substrate can be taken out of the furnace body. In this way, a large number of semiconductor substrates arranged in the vertical direction in a stacked state are horizontally moved toward the furnace body via the boat or away from the furnace body in the front surface of the furnace body, and the large number of semiconductor substrates are simultaneously moved. Can be inserted and removed. Therefore, regardless of whether the lined position is the upper part or the lower part of the boat, the heating time for a large number of semiconductor substrates is uniform, and a uniform film forming process can be performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the vertical diffusion furnace of the present invention will be described below with reference to FIGS.

In FIG. 1, 1 is a furnace core tube and 2 is a furnace core tube 1.
Furnace bodies 3, 4 provided with are door portions provided so as to be movable with respect to the furnace body 2 (see arrows A and B). The furnace core tube 1
Is composed of parts 1a, 1b and 1c respectively corresponding to the fixed furnace body 2 and the movable door parts 3 and 4 as shown in the drawing. The furnace core tube 1 is formed to have a substantially cylindrical shape by coupling the respective portions 1a, 1b, 1c to each other. Note that FIG. 1 shows a state in which they are separated from each other.

A heater 5 is set and constructed around the furnace core tube 1, and the heater 5 is provided so as to be embedded in the furnace body 2 and the like. The heater 5 can be provided also in the door portions 3 and 4. That is, in the door portions 3 and 4, heaters can be provided outside the portions 1b and 1c of the furnace core tube 1, respectively.

As shown by arrows A and B in the figure, the door portions 3 and 4 can be moved via a drive / guide mechanism or the like (not shown) so that they can approach and separate from each other. For example, by approaching and connecting with each other, each of the parts 1 is formed so as to form the cylindrical core tube 1 as described above.
a, 1b and 1c are connected to each other. Further, as shown in the drawing, the openings 6 are formed in the front surface of the furnace body 2 by being separated from each other. The opening 6 is closed when the doors 3 and 4 are closed, and the opening width of the opening 6 has a dimension that allows a boat having semiconductor substrates, which will be described later, to be inserted therethrough.

Further, in the figure, reference numeral 7 is a semiconductor substrate arranged in a stack in a plurality of rows in the vertical direction, and 8 is a boat for arranging and supporting the semiconductor substrate 7. In the boat 8, for example, a maximum of 134 semiconductor substrates 7 can be arranged in a row. As shown in FIG. 1, the boat 8 is installed on the front side of the opening 6. In addition, the boat 8 has a drive mechanism 9
It is moved into the furnace body 2 by the reciprocating motion, and thus reciprocates as shown by the arrow C.

Next, the operation of the vertical diffusion furnace according to the present invention will be described. When the boat 8 in which the semiconductor substrates 7 are lined up is inserted into the furnace body 2, the door portions 3 and 4 move in the directions of arrows A and B so that the door portions 3 and 4 move away from each other, thereby opening the front portion of the furnace body 2. 6 is formed. Then, the boat 8 has the drive mechanism 9 described above.
As shown in FIG. 2, it is inserted from the front of the furnace body 2 to the inner side thereof via. When inserting this boat 8,
The furnace body 2 is in a heated state by the action of the heater 5, and therefore, at the same time when the boat 8 is inserted, the heating process is immediately started on the semiconductor substrate 7. After the boat 8 in which the semiconductor substrates 7 are lined up is completely inserted and set in the furnace core tube 1, the doors 3 and 4 are moved in the opposite direction to close the opening 6 again. The predetermined heat treatment is continued.

When the required heating and holding time in the film forming process has elapsed, the door portions 3 and 4 move away from each other, so that the opening portion 6 is formed again in the same manner as described above. Then, the boat 8 in which the semiconductor substrates 7 are arranged in a row through the opening 6 that has been opened.
Of the semiconductor substrate 7 is moved to the front, whereby the semiconductor substrate 7
Can be taken from.

As described above, a large number of semiconductor substrates 7 arranged in the vertical direction in the stacked state are horizontally moved toward or away from the furnace body 2 via the boat 8, and thus, A large number of semiconductor substrates 7 are simultaneously inserted and removed on the front surface of the furnace body 2. Therefore, regardless of whether the lined position is the upper part or the lower part of the boat 8, the heating time for a large number of semiconductor substrates 7 is uniform, and a uniform film forming process can be performed.

In the above embodiment, the case where the door portions 3 and 4 are moved so as to be separated from each other in order to form the opening portion 6 has been described. In addition, as shown in FIG. Alternatively, it may be performed in a double door system. That is, in FIG. 3, the door portion 3'and the door portion 4'are pivotally supported by the furnace body 2 at one end thereof, and the opening portions are appropriately opened by rotating the door portions 3'and 4'as shown. 6 can be formed, and the same effect as that of the above embodiment can be obtained.

[0020]

As described above, according to the present invention, the boat in which the semiconductor substrates are arranged can be inserted and removed from the front of the furnace body, so that all the semiconductor substrates are irrespective of the setting position in the boat. The heating of the substrates can be started at the same time and finished at the same time, which makes it possible to substantially eliminate the difference between the heating and holding times among a large number of semiconductor substrates. Further, there is an advantage that the formed film thickness can be made uniform and the quality of the semiconductor device can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration according to an embodiment of a vertical diffusion furnace of the present invention.

FIG. 2 is a plan view showing a state when a semiconductor substrate is inserted in the vertical diffusion furnace of the present invention.

FIG. 3 is a plan view showing a modified example of a door section according to the vertical diffusion furnace of the present invention.

[Explanation of symbols]

 1 Furnace Core Tube 2 Furnace Body 3,4 Door Section 5 Heater 6 Opening 7 Semiconductor Substrate 8 Boat

Claims (2)

[Claims] 1. A vertical diffusion furnace having a furnace core tube capable of accommodating a large number of semiconductor substrates in a longitudinal direction in a furnace body, so that the semiconductor substrates can be inserted into and removed from the front surface of the furnace body. A vertical diffusion furnace having an opening / closing opening. 2. The vertical diffusion unit according to claim 1, wherein the furnace body has a door portion that can be opened and closed, and the opening portion is formed by opening and closing the door portion. Furnace.