JP2002280375A - Substrate treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate treatment apparatus which enhances a cross-sectional uniform heating property. SOLUTION: The batch-type vertical hot wall-type low-pressure CVD apparatus is provided with a process tube, which is constituted of an inner tube 2 and an outer tube 3. The inner tube 2 is constituted of a heat insulating part 2a which is made of quartz, which is formed in a short cylindrical shape and which is arranged outside a soaking region on the side of a furnace port 5 and a soaking part 2b which is made of silicon carbide, which is formed in a long cylindrical shape and which is arranged so as to correspond to the soaking region. Consequently, the quartz heat insulating part will not deprive heat of the soaking part as a part, corresponding to the soaking region in the inner tube of heat, and the cross-sectional soaking property of the inner tube will not deteriorate. Consequently, the temperature distribution of the soaking region is maintained to be uniform by the soaking part in the inner tube, and the distribution of film thickness inside a wafer group (between wafers) which depends on the temperature distribution and inside a wafer plane becomes uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing apparatus. For example, the present invention relates to a semiconductor wafer (hereinafter, referred to as a wafer) as a substrate on which a semiconductor integrated circuit device (hereinafter, referred to as an IC) is formed. Decompression CV for depositing (deposition) ₃ N ₄ ) or polysilicon
The present invention relates to a device effectively used for a D device or a diffusion device used not only for oxidation treatment and diffusion, but also for reflow for carrier activation and planarization after ion implantation.

[0002]

2. Description of the Related Art In a method of manufacturing an IC, a batch type vertical hot wall type low pressure CVD apparatus is widely used for depositing a CVD film such as silicon nitride or polysilicon on a wafer. A batch-type vertical hot-wall type reduced-pressure CVD apparatus (hereinafter, referred to as a CVD apparatus) includes a process tube which is constituted by an inner tube forming a processing chamber into which a wafer is loaded and an outer tube surrounding the inner tube, and which is installed vertically. , A gas introduction pipe for introducing a source gas into the inner tube, an exhaust pipe for evacuating the process tube, and a heater laid outside the process tube to heat the inside of the process tube. Is carried into the inner tube from the furnace port at the lower end while being held vertically aligned by the boat, the raw material gas is introduced into the inner tube from the gas introduction pipe, and the inside of the process tube is heated by the heater. CVD on the wafer
The membrane is configured to be deposited.

In a conventional CVD apparatus of this type, an inner tube that functions as a heat equalizing tube inside a process tube is made of silicon carbide (SiC) over its entire length.
Alternatively, it is formed of quartz (SiO ₂ ).

[0004]

SUMMARY OF THE INVENTION The aforementioned conventional CVD method
In the apparatus, since the inner tube extends to the low-temperature region of the furnace port, when the inner tube is formed of silicon carbide (SiC), a portion corresponding to the furnace port has a uniform temperature of the inner tube. Since the heat of the portion corresponding to the region is removed by heat conduction, there is a problem that the uniformity of the cross section is deteriorated. Further, when the inner tube is formed of quartz (SiO ₂ ), there is a problem that the effect of improving the temperature distribution is small due to poor heat conduction.

[0005] An object of the present invention is to provide a substrate processing apparatus capable of improving cross-sectional uniformity.

[0006]

According to a first aspect of the present invention, there is provided a substrate processing apparatus comprising: a process tube having an inner tube and an outer tube; And a portion corresponding to the outside of the soaking area is formed of quartz. Further, the inner tube is characterized in that at least a portion in contact with the manifold is formed of quartz, and other portions are formed of silicon carbide.

According to the above-described means, since the portion corresponding to the low-temperature region of the furnace port of the inner tube is formed of quartz, the heat of the portion corresponding to the soaking region of the inner tube is removed by heat conduction. Therefore, it is possible to prevent a decrease in cross-sectional uniformity. As a result, since the uniformity of the temperature distribution in the soaking region can be maintained, the uniformity of the film thickness distribution within the substrate surface and between the substrates can be improved.

[0008]

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

In the present embodiment, a substrate processing apparatus according to the present invention is a CVD apparatus (batch type) used for depositing, for example, silicon nitride on a wafer as a substrate on which an IC is manufactured in an IC manufacturing method. (A vertical hot wall type reduced pressure CVD apparatus).

As shown in FIG. 1, the CVD apparatus includes a vertical process tube 1 which is vertically disposed so that a center line is vertical and is fixedly supported. It is composed of a tube 2 and an outer tube 3. The inner tube 2 is formed in a cylindrical shape whose inner diameter is larger than the outer diameter of the wafer, and the outer tube 3 is formed in a cylindrical shape whose inner diameter is larger than the outer diameter of the inner tube 2. The inner tube 2 is formed in a cylindrical shape having upper and lower ends opened. The hollow portion of the inner tube 2 substantially serves as a processing chamber 4 into which a plurality of wafers held in a vertically aligned state by a boat are carried. Is formed. The lower end opening of the inner tube 2 substantially constitutes a furnace port 5 for taking in and out a wafer as a substrate to be processed.

In this embodiment, as shown in FIG. 2A, the inner tube 2 has a heat insulating portion 2a integrally formed into a short cylindrical shape with quartz, and a long cylindrical shape with silicon carbide. Soaking part 2b integrally molded with
It is composed of The heat insulating portion 2a made of quartz is arranged at a portion corresponding to the outside of the soaking region of the inner tube 2, that is, a portion on the furnace port 5 side, and is vertically supported by a manifold 6 described later, and its length will be described later. It is set to be slightly shorter than the heat insulating cap portion 16 of the boat 11. A lower flange portion 2c is formed on the outer periphery of the upper end of the heat insulating portion 2a, and a male fitting portion 2d protrudes from the upper surface of the lower flange portion 2c. An upper flange portion 2e is formed on the outer periphery of the lower end of the heat equalizing portion 2b formed of silicon carbide, and a female fitting portion 2f is buried under the lower surface of the upper flange portion 2e. The heat equalizing portion 2b is integrated on the heat insulating portion 2a in a state where the female fitting portion 2f is fitted to the male fitting portion 2d and the upper flange portion 2e is in contact with the lower flange portion 2c. It is connected and vertically supported. The heat equalizing section 2b is configured to correspond to the heat equalizing area of the entire area of the inner tube 2, and has a length from the upper surface of the heat insulating cap section 16 of the boat 11 described later to the upper surface of the upper end plate 12. It is set to be larger than the length.

The outer tube 3 is formed in a cylindrical shape whose inner diameter is larger than the outer diameter of the inner tube 2 and whose upper end is closed and whose lower end is opened. . A lower end portion between the inner tube 2 and the outer tube 3 is hermetically sealed by a manifold 6 formed in a circular ring shape. The manifold 6 is used for replacing the inner tube 2 and the outer tube 3 with each other. 2
And the outer tube 3 are detachably attached. By supporting the manifold 6 on the machine frame 20 of the CVD apparatus, the process tube 1 is in a vertically installed state.

An exhaust pipe 7 is provided above the side wall of the manifold 6.
The exhaust pipe 7 is connected to a high vacuum exhaust device (not shown) so that the processing chamber 4 can be evacuated to a predetermined degree of vacuum. The exhaust pipe 7 is in communication with a gap formed between the inner tube 2 and the outer tube 3, and the gap between the inner tube 2 and the outer tube 3 allows the exhaust path 8 to have a constant cross-sectional shape. Is formed in a circular ring shape. Since the exhaust pipe 7 is connected to the manifold 6, the exhaust pipe 7 has a cylindrical hollow body and is arranged at the lowermost end of a vertically extending exhaust path 8.

A gas introduction pipe 9 is connected to the lower part of the side wall of the manifold 6 so as to communicate with the furnace port 5 of the inner tube 2. The gas introduction pipe 9 is connected to a raw material gas supply device and a carrier gas supply device. (Not shown). The gas introduced into the furnace port 5 by the gas introduction pipe 9 flows through the processing chamber 4 of the inner tube 2, passes through the exhaust path 8, and is exhausted by the exhaust pipe 7. A pressure gauge 10 is connected to another portion of the lower portion of the side wall of the manifold 6 so as to communicate with the furnace port 5 of the inner tube 2, and the pressure gauge 10 is located in an upstream area of the processing chamber 4 of the inner tube 2. It is configured to measure the pressure of

A cap 17 for closing the lower end opening is brought into contact with the manifold 6 from below in the vertical direction. The cap 17 is formed in a disk shape substantially equal to the outer diameter of the outer tube 3, and is configured to be vertically moved up and down by an elevator (not shown) installed vertically outside the process tube 1. . A boat 11 for holding a wafer W as a substrate to be processed is vertically supported on the center line of the cap 17.

The boat 11 has an upper end plate 12 and a lower end plate 13, and a plurality of boats (three in the present embodiment) vertically provided between the upper end plate 12 and the lower end plate 13. ) Are provided, and the three holding members 14 are provided with a plurality of (for example, 172) holding grooves 15 arranged at equal intervals in the longitudinal direction and opposed to each other in the same horizontal plane. It is engraved to open. The boat 11 is configured such that the outer peripheral edges of the wafers W are inserted between the holding grooves 15 of the three holding members 14 so that the plurality of wafers W are aligned and held horizontally and centered. It has become.

A heat insulating cap 16 is disposed between the boat 11 and the cap 17.
Is configured so that the lower end plate 13 of the boat 11 is separated from the position of the furnace port 5 by an appropriate distance by supporting the boat 11 in a state of being lifted from the upper surface of the cap 17. That is, the heat-insulating cap 16 is set so that the group of wafers W held on the boat 11 corresponds to the soaking part 2 b of the inner tube 2.

A heater 18 for heating the inside of the process tube 1 is provided concentrically outside the outer tube 3 so as to surround the outer tube 3.
The outside of 8 is covered with a heat insulating cover 19. The heater 18 is divided into an upper heater section 18a, a center upper heater section 18b, a center lower heater section 18c, and a lower heater section 18d in this order from the upper side. And are controlled independently of each other. The heater 18 and the heat insulating cover 19 are vertically installed by being supported by a machine frame 20 of the CVD apparatus.

Next, the operation of the CVD apparatus according to the above configuration will be described for the case where a silicon nitride (Si ₃ N ₄ ) CVD film is formed on a wafer.

As shown in FIG. 1, the boat 11 holding a plurality of wafers W arranged thereon is placed on a cap 17 in a state in which the direction in which the groups of wafers W are arranged is vertical, and is raised by an elevator. Then, it is carried into the processing chamber 4 from the furnace port 5 of the inner tube 2, and is left in the processing chamber 4 while being supported by the cap 17. In this state, the cap 17 is in a state where the furnace port 5 is sealed.

The inside of the process tube 1 is evacuated to a predetermined degree of vacuum (several tens of Pa or less) by an exhaust pipe 7.
At this time, the pressure inside the process tube 1 is
And the degree of vacuum is feedback controlled. Further, the inside of the process tube 1 is entirely heated to a predetermined temperature (for example, about 760 ° C.) by the heater 18. At this time, the temperature distribution in the region where the wafer W group of the boat 11 exists in the processing chamber 4 is uniformly maintained by the inner tube 2.

Next, a raw material gas 21 as a processing gas is supplied to the processing chamber 4 of the inner tube 2 through a gas introduction pipe 9. When depositing a CVD film of Si ₃ N ₄ , SiH ₂ Cl ₂ and NH ₃
Alternatively, SiH ₄ and NH ₃ are introduced into the processing chamber 4.

The introduced raw material gas 21 rises in the processing chamber 4 of the inner tube 2 and passes through the inner tube 2 through the upper end opening.
The gas flows out into an exhaust path 8 formed by a gap between the outer tube 3 and the exhaust tube 7 and is exhausted from an exhaust pipe 7. The source gas 21 comes into contact with the surface of the wafer W when passing through the processing chamber 4. Due to the CVD reaction of the source gas 21 by this contact, a CVD film of Si ₃ N ₄ is deposited (deposited) on the surface of the wafer W. At this time, the temperature distribution in the processing chamber 4 is uniformly maintained by the inner tube 2, so that the thickness distribution of the CVD film in the wafer group (between the wafers) and in the wafer surface becomes uniform.

After a lapse of a predetermined processing time in which the Si ₃ N ₄ CVD film is deposited by a desired deposition film thickness, the cap 17 is lowered to open the furnace port 5 and hold the boat on the boat 11. In this state, the group of wafers W is carried out of the process tube 1 from the furnace port 5.

By the way, as shown in FIG. 2B, in the case of the conventional example in which the entire length of the inner tube 2 'is integrally formed of silicon carbide, the inner tube 2' made of silicon carbide is used. The lower end A of the inner tube 2 ′ extends to the low temperature region of the furnace port 5, so that the lower end A of the cooled inner tube 2 ′ is a portion corresponding to the soaking region of the inner tube 2 ′. Of the inner tube 2 ′, so that the cross-sectional uniformity of the inner tube 2 ′ is deteriorated. If the cross-sectional thermal uniformity of the inner tube 2 ′ deteriorates, the temperature distribution inside the process tube 1 becomes non-uniform in the above-mentioned film forming process, and the inside of the wafer group (between the wafers) and the wafer surface depend on this temperature distribution. The film thickness distribution inside becomes uneven.
The same applies to the case where the entire length of the inner tube is integrally formed of quartz.

In this embodiment, as shown in FIG. 2 (a), the inner tube 2 is made of quartz and is provided with a heat insulating portion 2a arranged to correspond to a low temperature region.
And a soaking section 2b formed of silicon carbide and arranged so as to correspond to the soaking area. Since the heat insulating section 2a is arranged in the low temperature area of the furnace port 5,
Since the heat insulating portion 2a does not remove the heat of the heat equalizing portion 2b corresponding to the heat equalizing region of the inner tube 2, the cross-sectional uniformity of the inner tube 2 does not deteriorate. Therefore, since the temperature distribution in the heat equalizing region is maintained uniform by the heat equalizing portion 2b of the inner tube 2, the inside of the wafer W group (between the wafers) and the wafer surface depending on this temperature distribution in the above-described film forming process. The film thickness distribution inside becomes uniform. By the way, if the heat insulating portion 2a in contact with the manifold 6 of the inner tube 2 is formed of quartz, the heat insulating portion 2a does not take away the heat of the heat equalizing portion 2b. It may be formed of silicon carbide beyond the soaking area.

The present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the gist of the present invention.

The film forming process is not limited to a process for forming a Si ₃ N ₄ CVD film, but may be a process for forming another CVD film such as polysilicon or silicon oxide.

The CVD apparatus is not limited to a batch type vertical hot wall type reduced pressure CVD apparatus, but may be another type of CVD apparatus such as a horizontal hot wall type reduced pressure CVD apparatus.

Further, the semiconductor manufacturing apparatus is not limited to the CVD apparatus, and may be applied not only to oxidation processing and diffusion, but also to a diffusion apparatus used for reflow for activation of carriers and flattening after ion implantation. it can.

In the above-described embodiment, the case where the processing is performed on the wafer has been described. However, the processing target may be a photomask, a printed wiring board, a liquid crystal panel, a compact disk, a magnetic disk, and the like.

[0032]

According to the present invention, the uniformity of the processing state, such as the film thickness distribution of the substrate to be processed, can be improved since the cross-sectional uniformity can be improved, and the quality and reliability of the substrate processing apparatus can be improved. Properties and manufacturing yield can be improved.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a CVD apparatus according to an embodiment of the present invention.

FIGS. 2A and 2B are front cross-sectional views of an inner tube for explaining the operation thereof, wherein FIG. 2A shows an inner tube according to the present embodiment, and FIG. 2B shows an inner tube according to a comparative example. I have.

[Explanation of symbols]

W: wafer (substrate), 1: process tube, 2: inner tube, 2 ': inner tube of comparative example, 2a: heat insulating portion, 2b: heat equalizing portion, 2c: lower flange portion, 2d: male fitting portion 2e: Upper flange portion, 2f: Female fitting portion, 3: Outer tube, 4: Processing chamber, 5: Furnace port, 6: Manifold, 7 ...
Exhaust pipe, 8 ... exhaust path, 9: gas introduction pipe, 10: pressure gauge,
11 boat, 12, 13 end plate, 14 holding member, 1
5 ... holding groove, 16 ... heat insulating cap part, 17 ... cap,
18 ... heater, 19 ... heat insulating cover, 20 ... machine frame, 21 ...
Source gas (processing gas).

Claims (2)

[Claims] 1. A substrate processing apparatus in which a process tube includes an inner tube and an outer tube, wherein a portion of the inner tube corresponding to the soaking region is formed of silicon carbide, and a portion corresponding to outside the soaking region. A substrate processing apparatus characterized in that is formed of quartz. 2. A substrate processing apparatus in which a process tube includes an inner tube and an outer tube, wherein at least a portion of the inner tube that contacts the manifold is formed of quartz, and other portions are formed of silicon carbide. A substrate processing apparatus.