JPS61190948A - Film forming device - Google Patents

Abstract

PURPOSE:To enable to form a uniform film on wafers by a method wherein process gas is uniformly fed in the process tube. CONSTITUTION:The group of through-holes 10 of a process tube 4 is provided in such a way that the through-holes on parts of the process tube 4, where are located near the intake vent 5 of a box 3, are formed of those of smaller diameters and the penetrated holes on parts of the process tube 4, where are located near the exhaust vents 9 of a substrate 2, are formed of those of larger diameters. For that, process gas 16a of a strong concentration in immediately after being introduced in a processing chamber 7 is made to flow in the processing chamber 7 through the through-holes 10a having the smaller caliber, while process gas 16b of a diluted concentration is made to flow in the processing chamber 7 through through-holes 10b having larger diameters. The relative concentration of process gas 16, which is made to flow in the processing chamber 7 in such a way, is held to a constant owing to the difference between the calibers due to the positions of the through-holes 10. Furthermore, as wafers 14, which are the matters to be processed, are being made to revolve in the interior of the processing chamber 7, the process gas 16 is made to uniformly flow on the wafers 14 and even though some among the wafers 14 are ones being held at whatever positions on a jig 15, a uniform film is formed on such wafers.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to film formation technology, particularly in the manufacturing of semiconductor devices,
Techniques 44j that are effective when applying film processing to semiconductor substrates
It is related to.

[Background Art] In the manufacturing process of semiconductor devices, a film forming apparatus is used to form an oxide film on the surface of a semiconductor substrate (hereinafter referred to as a wafer).
A conceivable structure is one in which a processing gas such as oxygen (Ox) is supplied to a plurality of wafers arranged vertically in a horizontally long processing container from a single inlet provided horizontally.

However, as the wafers to be processed become larger in diameter due to the higher integration of semiconductor devices, the processing containers that house the wafers also become larger in diameter. It is known that repeated heating at the processing temperature of about 1200°C may cause thermal fatigue, and the container itself may be damaged due to its own weight.

Therefore, it is possible to make the processing container (hereinafter referred to as process tube) vertical to ensure a certain level of strength.
In such a vertical process tube, processing gas is supplied from a single inlet located at the top or bottom of the process tube, so there is a difference in gas concentration near the inlet and outlet. The inventor of the present invention revealed that there is a possibility that variations in the film forming process occur due to non-uniform gas flow.

In addition, as an example of a detailed description of the film forming technology, see rf
"C Mounting Technology" (Japan Microelectronics Association), pages 41 to 46.

[Object of the Invention] An object of the present invention is to provide a film forming technique that can form a uniform film.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the Invention] A brief overview of typical inventions disclosed in this application is as follows.

That is, by using a vertical film forming apparatus having a structure consisting of a process tube with a plurality of through holes and a box formed on the outer circumferential side of the process tube so as to surround the process tube, the processing gas can be removed. It can be supplied into the process tube in a uniform manner to form a uniform film.

In addition, the through hole near the inlet where the gas concentration is high is made small in diameter.
By making the diameter of the through hole larger toward the vicinity of the outlet where the gas concentration decreases, uniform reaction can be ensured at any location within the processing space, and uniform film formation can be further promoted.

[Example] FIG. 1 is a partial sectional view showing a film forming apparatus that is an example of the present invention.

In the film forming apparatus 1 of this embodiment, a bell jar-shaped box 3 having approximately the same diameter as the substrate 2 and closed at one end is mounted on a disk-shaped substrate 2 made of quartz glass. A cylindrical process tube 4 having a slightly smaller diameter than the box 3 is mounted on the substrate 2 along the central axis inside the box 3 .

Here, the box 3 is made of quartz glass, has a suction port 5 at its closed end, and a heater 6 is installed on the outer periphery of the side wall of the box so as to heat the inside of the box 3 and the process tube 4. ing.

The process tube 4 is made of quartz glass and has a cylindrical shape that is slightly shorter than the box 3 with one end closed.
A space surrounded by the box 3 and the substrate 2 is divided into a processing chamber 7 and an annular gas passage 8. A discharge port 9 is provided at the bottom of the processing chamber 7 formed by the process tube 4 on the substrate 2 side.
are provided in communication with the substrate 2. Further, a plurality of through holes 10 are formed in the side wall of the process tube 4 so as to communicate between the inside and outside of the process tube 4, and the opening diameter of the through holes 10 is set at a portion near the suction port 5 of the box 3. has a small diameter, and the diameter becomes larger toward the discharge port of the substrate 2.

A substantially disk-shaped turntable 11 made of quartz glass is provided on the substrate 2 of the processing chamber 7, and the turntable 11 is connected to the motor 13 by a shaft 12 extending in the opposite direction to the processing chamber 7. , and is in a state where it can rotate around the central axis within the processing chamber 7.

Further, on the turntable 11, a jig 15 is placed which holds a plurality of wafers 14 as objects to be processed, aligned horizontally and parallel to each other.

Next, the operation of this embodiment will be explained.

First, a plurality of wafers 14 are aligned and held on a jig 15, and the jig 15 is placed in a standing position at the center of the turntable 11 and inserted into the processing chamber 7.

Next, when the turntable 11 is rotated by the motor 13 via the shaft 12, the group of wafers 14 held by the jig 15 on the turntable 11 will revolve inside the processing chamber 7.

When the revolution becomes stable and the inside of the processing chamber 7 heated by the heater 6 becomes a predetermined atmosphere, the processing gas 16 is introduced from the suction port 5 into the gas passage 8 partitioned by the box 3 and the process tube 4 .

The processing gas 16 is introduced into the processing chamber 7 through each through hole 10 of the process tube 4 through the gas passage 8, and is introduced into the processing chamber 7 through the gas passage 8 and the wafer 14.
This causes the particles to form an oxide film, which flows out from the outlet 9 in the substrate 2.

At this time, the 10 groups of through holes of the process tube 4 are formed with a small diameter in the part near the inlet 5 of the box 3, and
The one near the discharge port 9 has a large diameter. Therefore, the highly concentrated processing gas 16a immediately after introduction flows into the processing chamber 7 through the small diameter through hole 10a, and the reduced concentration processing gas 16b flows into the processing chamber 7 through the large diameter through hole 10b.

In this way, the relative concentration of the processing gas 16 flowing into the processing chamber 7 is kept constant due to the difference in diameter depending on the position of the through hole 10. Moreover, since the wafer 14, which is the object to be processed, revolves inside the processing chamber 7, the processing gas 16 flows uniformly over the wafer 14, regardless of the position of the wafer held on the jig 15. A uniform product film is formed.

[Effects] (1) The vertical film forming apparatus has a structure consisting of a process tube with a plurality of through holes and a box formed on the outer circumferential side of the process tube so as to surround the process tube. Accordingly, the processing gas can be uniformly supplied into the process tube, and uniform film formation can be performed.

(2) By forming the through holes in the process tube with a small diameter near the inlet of the box and increasing the diameter toward the outlet of the substrate, the relative flow of gas into the processing space is reduced. The concentration can be kept constant and the produced film can be made more uniform.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, in the embodiments, the material of the box etc. has been described only using quartz glass, but the material is not limited to this, and any material may be used as long as it has excellent corrosion resistance against acids and heat resistance.

[Field of Application] In the above explanation, the invention made by the present inventor was mainly applied to a so-called oxide film forming apparatus, which is the field of application that formed the background of the invention, but the present invention is not limited to this. For example, it is an effective technique even when applied to a plasma CVD apparatus.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing a film forming apparatus which is an embodiment of the present invention. ]... Film forming device, 2... Substrate, 3... Box, 4... Process tube, 5... Inlet, 6...
・Heater, 7...processing chamber, 8...gas passage, 9...
- Discharge port, 10... Through hole, 11... Turntable, 13... Motor, 14... Wafer, 15... Jig, 16... Processing gas.

Claims (1)

[Claims] 1. A vertical film forming apparatus that accommodates a plurality of semiconductor substrates horizontally, comprising a process tube with a plurality of through holes, and a process tube on the outer circumferential side of the process tube. 1. A film forming apparatus comprising: a box formed to surround the film. 2. The film forming apparatus according to claim 1, wherein the plurality of through holes gradually become larger in diameter from the vicinity of the processing gas inlet to the vicinity of the discharge port. 3. The film forming apparatus according to claim 1, wherein the process tube is made of quartz.