JPH1041251A - Device and method for cvd - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent particles from being produced when a CVD film is deposited by installing a guide ring for directing a purge gas flow from a purge gas blowing section provided below the peripheral edge section of a substrate to be treated toward a point above the center of the surface to be treated of the substrate. SOLUTION: Before a blanket W film 24 is deposited on a semiconductor wafer 3, an interlayer insulating film 22 is deposited on a semiconductor substrate 21 and a Ti film and a TiN film 23 are deposited on the entire surface of the substrate by the sputtering method. Then a guide ring 30 is provided outward from the peripheral edge section of the wafer 3 and the angle θ between the bottom face of the ring 30 and the side face of the ring 30 is adjusted to 80 deg. so that a purge gas flow can be discharged upward from the side wall of the wafer 3 and toward a point above the center of the wafer 3 through the clearance between a susceptor 8 and ring 30. Therefore, the occurrence of particles which are produced when a CVD film is deposited can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a CVD apparatus and a C
More specifically, the present invention relates to a CVD apparatus and a CVD method for forming a tungsten film or the like having poor adhesion to a semiconductor wafer on which an interlayer insulating film has been deposited.

[0002]

2. Description of the Related Art In recent years, as semiconductor devices have become highly integrated and miniaturized, contact holes of elements and the like constituting the semiconductor devices have been increasingly miniaturized, and the ratio between the depth of the contact hole and the diameter of the contact hole, the so-called aspect ratio. And the conventional method for forming an electrode wiring using an Al alloy film has poor step coverage, so that this method for forming an electrode wiring cannot be used. In addition, since the electrode wiring has poor electromigration and stress migration resistance due to the Al alloy film, it is no longer used in a semiconductor device with high integration and high speed.

In order to form an electrode wiring in the manufacture of a semiconductor device using a contact hole having a high aspect ratio, CVD is used.
(Chemical Vapor Deposition
n) Deposition of a tungsten film (blanket W film) by a method and formation of a buried plug of tungsten (tungsten plug) by etch back, formation of an electrode portion by a buried plug of tungsten by a selective CVD method of a tungsten film, and contact hole portion The formation of the electrode wiring is performed separately from the formation of the wiring connecting the embedded plugs.

With the above-described tungsten plug formation, CV
Conventional CV used for blanket W film deposition by D method
The D apparatus and the CVD method will be described with reference to FIGS.

As shown in FIG. 4, a conventional CVD apparatus 1 mounts a semiconductor wafer 3 in a chamber 2 which is a CVD reaction vessel and heats the semiconductor wafer 3 and a semiconductor wafer mounting section 4. The gas blowout unit 5 is provided at a position facing the mounting unit 4 and emits a reaction gas for forming a tungsten film. Further, the chamber 2 is provided with an exhaust port 6 for discharging by-products and unreacted gas from the chamber 2 when a tungsten film is formed by CVD.

The semiconductor wafer mounting portion 4 includes a susceptor 8 having a built-in heater 7 and a support portion surrounding the susceptor 8 and supporting a shielding plate 9 for limiting an area of a blanket W film deposited on the semiconductor wafer 3. 10. The gas blowing section 5 is formed in a hollow disk shape, and a reaction gas is introduced from a reaction gas supply source (not shown) through a gas pipe 11, and a large number of gas blowing sections 5 are provided on the surface of the gas blowing section 5 facing the semiconductor wafer 3. The small holes 12 are provided so that the reactive gas is uniformly supplied to the surface of the semiconductor wafer 3.

Next, a CVD method for forming a blanket W film using this CVD apparatus will be described. First, an interlayer insulating film is deposited on a semiconductor substrate on which constituent elements of a semiconductor device are formed, a contact hole is formed, and a semiconductor film 3 on which a Ti film and a TiN film are deposited by a sputtering device is placed on a susceptor 8 of the CVD device 1. Then, a shielding plate 9 for limiting the area of the blanket W film deposited on the semiconductor wafer 3 is attached to the support portion 10 in a state of being in close contact with the surface of the semiconductor wafer 3. Next, the inside of the chamber 2 is evacuated, and subsequently, a temperature controller for the susceptor 8 (not shown)
The power is supplied to the heater 7 to heat the susceptor 8, and the semiconductor wafer 3 is heated to 400 to 500 ° C. Thereafter, a mixed gas of WF ₆ gas, H ₂ gas, and Ar gas, which is a reaction gas for forming a blanket W film, is introduced from the reaction gas supply unit into the chamber 2 through the gas blowing unit 5, and the semiconductor is formed. A blanket W film is deposited on the surface of the wafer 3.

The details of the CVD method of the blanket W film using the above-described CVD apparatus 1 will be described with reference to FIG. 5, which is an enlarged view of a portion B in FIG. First, as shown in FIG. 5, the susceptor 8 before the blanket W film 24 is deposited.
In the semiconductor wafer 3 placed on the substrate, an interlayer insulating film 22 is deposited on a semiconductor substrate 21, and a Ti film (not shown) is formed thereon.
And TiN film 23, in a restricted form inwardly than the distance L ₁ peripheral portion of the semiconductor substrate 21 has a configuration which is deposited by sputtering. Here, the Ti film (not shown) is sputtered in such a manner as to be further limited inside the region where the TiN film 23 is formed, or a Ti film or Ti film is formed.
After the sputtering of the N film 23, the portion where the Ti film is exposed on the surface of the semiconductor wafer 3 is turned into a TiN film by heat treatment in a nitrogen (N) -based gas atmosphere, so that the Ti film is not exposed on the surface. This is because when the Ti film is exposed on the surface of the semiconductor wafer 3, the WF ₆ gas at the time of forming the blanket W film 24 is H ₂ gas.
F generated by being reduced by the gas reacts with Ti,
F ₃ and TiF ₄ are generated and expand in volume, and Ti
This is because the N film is stripped, which causes particles, which lowers the manufacturing yield of the semiconductor device.

[0009] Next, on the semiconductor wafer 3 placed on the susceptor 8, limits the region formed on the semiconductor wafer 3 of the blanket W film 24, on the inner side of the distance L ₂ peripheral portion of the semiconductor substrate 21 The shielding plate 9 is arranged in close contact. This is because a blanket W film having poor adhesion is not deposited on the interlayer insulating film 22, and the blanket W film 24 deposited on the interlayer insulating film 22 is peeled off due to poor adhesion, causing particles and causing a semiconductor. This is to avoid a decrease in the production yield of the device. After the above-described semiconductor wafer 3 is heated by the susceptor 8 and reaches a predetermined temperature, a reaction gas for forming the blanket W film 24 is introduced, and the blanket W film 24 is deposited on the semiconductor wafer 3. Since the growth of the blanket W film 24 largely depends on the surface temperature of the workpiece to be deposited, the blanket W film 24 thinner than the semiconductor wafer 3 is deposited on the surface and side walls of the shielding plate 9 which is usually lower in temperature than the semiconductor wafer 3. . Then, the supply of the reaction gas is stopped, and the shielding plate 9 is moved to the support portion 1.
0, and the semiconductor wafer 3 is taken out from the semiconductor wafer mounting portion 4.

However, in the above-described deposition of the blanket W film 24 in the CVD apparatus, when the shielding plate 9 is removed from the support portion 10 and moved from above the semiconductor wafer 3, the space between the semiconductor wafer 3 and the side wall of the shielding plate 9 is formed. The so-called micro-peeling, in which the blanket W film 24 continuously deposited is peeled off, causes a problem of generating particles that become dust. If the semiconductor wafer 3 and the shielding plate 9 are arranged at a small interval to avoid the micro-peeling, the reaction gas enters through this gap and the blanket W film is formed on the interlayer insulating film 22 near the periphery of the semiconductor wafer 3. 2
4 is deposited, and the blanket W film 24 in this portion is peeled in a later step because of poor adhesion, and reduces the production yield of semiconductor devices as particles.

There has been proposed a CVD apparatus in which the semiconductor wafer 3 and the shielding plate 9 are arranged at a small distance from each other, and a purge gas is discharged toward the center of the semiconductor wafer 3 from this gap. Blanket W film 24 deposition on interlayer insulating film 22 near the periphery of semiconductor wafer 3 is avoided. However, in this CVD apparatus,
In the portion of the semiconductor wafer 3 directly below the shielding plate 9 and the portion of the semiconductor wafer 3 where the thickness of the blanket W film 24 is reduced by the influence of the purge gas from the side wall of the shielding plate 9 toward the center of the semiconductor wafer 3, Since the device is difficult to manufacture, the number of semiconductor devices obtained from one semiconductor wafer 3,
There arises a problem that the so-called theoretical yield decreases.

[0012]

SUMMARY OF THE INVENTION The present invention relates to the aforementioned C
It is an object of the present invention to solve problems in a VD apparatus and a CVD method. That is, an object of the present invention is to provide a CVD apparatus and a CVD method that prevent generation of particles due to deposition of a CVD film and improve the theoretical yield.

[0013]

Means for Solving the Problems A CVD apparatus and a CVD method of the present invention are proposed to solve the above-mentioned problems, and the CVD apparatus of the present invention mounts a substrate to be processed in a reaction vessel. In a CVD apparatus having a susceptor to be placed and heated, and a reactive gas discharge section, a purge gas blowing section is provided below a peripheral portion of a substrate to be processed mounted on the susceptor, and purge gas blowing is performed at a peripheral section of the substrate to be processed. A guide ring for directing the flow of the purge gas from the section toward the upper center of the processing surface of the substrate to be processed is provided around the periphery of the substrate to be processed.

According to the CVD method of the present invention, in the CVD method using the above-described CVD apparatus, a step of mounting a substrate to be processed on a susceptor, a step of blowing a purge gas from a purge gas blowing section into a reaction vessel, The method is characterized by comprising a step of blowing a reaction gas from a discharge section into a reaction vessel and a step of depositing a CVD film on a processing surface of a substrate to be processed.

According to the present invention, a purge gas blowing section is provided below the peripheral portion of the substrate to be processed mounted on the susceptor,
By providing a guide ring around the periphery of the substrate to be processed, a guide ring for directing the flow of the purge gas from the purge gas blowing section toward the upper center of the surface of the substrate to be processed is provided at the periphery of the substrate to be processed. It is possible to prevent the reaction gas for forming the CVD film from reaching the peripheral portion and prevent the CVD film from depositing on the peripheral portion of the substrate to be processed. Therefore, in a substrate to be processed having a region with poor adhesion to the CVD film at the peripheral portion of the substrate to be processed, C
Since the VD film is not formed, no dust is generated due to the peeling of the CVD film, and a decrease in the production yield of a device using the substrate to be processed, for example, a semiconductor device can be avoided.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. Components similar to those in FIGS. 4 and 5 referred to in the description of the prior art are denoted by the same reference numerals.

This embodiment is directed to a CVD apparatus and a CVD apparatus.
This is an example in which the present invention is applied to a method, which will be described with reference to FIGS. First, as shown in FIG. 1, a basic configuration of a CVD apparatus 1 is the same as that of a conventional example, and a substrate to be processed, for example, a semiconductor wafer 3 is placed in a chamber 2 which is a CVD reaction vessel and heated. It is roughly constituted by a mounting section 4 and a gas blowout section 5 provided at a position facing the semiconductor wafer mounting section 4 and emitting a reaction gas for forming a tungsten film.

The configuration of the semiconductor wafer mounting portion 4 includes a susceptor 8 having a built-in heater 7, a guide ring 30, and a support portion 10 surrounding the susceptor 8 and supporting the guide ring 30. A gas pipe 31 that supplies a purge gas from a purge gas supply unit (not shown) using an inert gas, for example, an Ar gas, is connected to the support unit 10. The purge gas introduced from the gas pipe 31 passes through the gap between the side wall of the susceptor 8 and the support 10 and further passes through the susceptor 8.
Through the gap between the semiconductor wafer 3 and the guide ring 30.

FIG. 2 is a schematic plan view of the semiconductor wafer mounting portion 4 viewed from above in a state where the semiconductor wafer 3 is mounted on the semiconductor wafer mounting portion 4 described above. As shown in FIG. 2, the mounting portion 8 of the susceptor 8 in direct contact with the semiconductor wafer 3
The peripheral edge of “a” is inside the peripheral edge of the semiconductor wafer 3, for example, about 1 mm inside, and the inner peripheral part of the guide ring 30 is outside the peripheral edge of the semiconductor wafer 3, for example, about 2 mm outside. The peripheral portion of the semiconductor wafer 3 has a circular portion and a linear portion of the orientation flat portion 3a, and the peripheral portion of the mounting portion 8a of the susceptor 8 and the inner peripheral portion of the guide ring 30 correspond to the peripheral portion of the semiconductor wafer 3. It is configured in a form similar to that of the above configuration. By doing so, as shown in FIG. 2, the purge gas blowing portions 32 are formed at equal intervals on the periphery of the semiconductor wafer 3.

Next, the vicinity of the purge gas blowing section 32 will be described in detail with reference to FIG. 3, which is an enlarged view of the section A in FIG. The susceptor 8 is located outside the periphery of the semiconductor wafer 3, and the mounting portion 8 a of the susceptor 8 on which the semiconductor wafer 3 is mounted
It is one step lower than the surface. On the other hand, the guide ring 30
Is fixed to the support portion 10 of the guide ring 30 at a position lower than the surface position of the mounting portion 8a of the susceptor 8.

The guide ring 30 is arranged from the upper surface of the semiconductor wafer 3.
The height H up to the upper surface is, for example, about 10 mm, and the angle θ between the bottom surface of the guide ring 30 and the side surface of the guide ring 30.
Is, for example, 80 °. If the height H of the guide ring 30 is too low, there is no effect of preventing the growth of the blanket W film on the peripheral portion of the semiconductor wafer 3, and if the height H is too high, the uniformity of the thickness of the blanket W film on the semiconductor wafer 3 deteriorates. If the angle θ of the side wall of the guide ring 30 is too small, there is no effect of preventing the growth of the blanket W film on the peripheral portion of the semiconductor wafer 3, and if it is larger than 90 °, not only does the blanket W film formation region become narrow, but also the semiconductor wafer 3 Since it is necessary to remove the guide ring 30 when placing the guide ring 30 on the susceptor 8, it is desirable that 60 ° ≦ θ ≦ 90 °. As a material of the guide ring 30, it is better to use a material that absorbs less heat such as radiant heat from the susceptor 8, for example, a quartz material. This is because, when a material having low heat absorption is used as the guide ring 30, the temperature of the guide ring 30 does not rise, so that the growth of the tungsten film on the surface of the guide ring 30 can be suppressed low, and the generation of dust can be suppressed.

The purge gas is introduced along the gap between the surface of the susceptor 8 and the bottom of the guide ring 30. When the purge gas reaches the side wall of the mounting portion 8a of the susceptor 8, the purge gas is formed by the gap between the side wall of the mounting portion 8a and the side wall of the guide ring 30. Is discharged upward from the purge gas blowing portion 32 at the peripheral portion of the semiconductor wafer 3.

Next, a CVD method for forming a blanket W film using this CVD apparatus will be described. First, an interlayer insulating film is deposited on a semiconductor substrate on which constituent elements of a semiconductor device are formed, a contact hole is formed, and a semiconductor film 3 on which a Ti film and a TiN film are deposited by a sputtering device is placed on a susceptor 8 of the CVD device 1. Place on. Next, the inside of the chamber 2 is evacuated, and then the power is supplied to the heater 7 by the temperature control device (not shown) of the susceptor 8 to heat the susceptor 8 to make the temperature of the semiconductor wafer 3 approximately 450 ° C.

Thereafter, a reaction gas for forming a blanket W film is sent from a reaction gas supply unit (not shown) to the gas blowing unit 5, and the reaction gas is introduced into the chamber 2 through a small hole of the gas blowing unit 5, and the CVD is performed. A blanket W film is deposited on the surface of the semiconductor wafer 3 by the method. This blanket W
The CVD conditions of the film are, for example, as follows. [CVD conditions for blanket W film] WF ₆ gas flow rate: 100 sccm H ₂ gas flow rate: 400 sccm Ar gas flow rate: 1500 sccm Pressure: 10 kPa Temperature: 450 ° C.

The details of the CVD method of the blanket W film using the above-described CVD apparatus 1 will be described with reference to FIG. 2 and FIG. 3 which is an enlarged view of a portion A in FIG. First, as shown in FIG. 3, before the blanket W film 24 is deposited, the semiconductor wafer 3 has an interlayer insulating film 22 deposited on a semiconductor substrate 21, and a Ti film (not shown) and a TiN film 23 thereon.
Are deposited on the entire surface of the semiconductor substrate 21 by a sputtering method. However, Ti film and TiN
After the film 23 is sputtered, the portion where the Ti film is exposed on the surface is turned into TiN by heat treatment in a nitrogen (N) gas atmosphere, so that the Ti film does not directly appear on the surface.

As shown in FIG. 2, the semiconductor wafer 3 is mounted on the susceptor 8 such that the peripheral portion of the mounting portion 8a of the susceptor 8 and the peripheral portion of the semiconductor wafer 3 are substantially equally spaced including the orientation flat portion 3a. It is mounted on the mounting portion 8a. At the time of CVD of the blanket W film 24, first, a purge gas such as an Ar gas is supplied from the purge gas blowout portion 32 below the peripheral portion of the semiconductor wafer 3 to about 1500 sc.
The reaction gas is discharged into the chamber 2 at a flow rate of about cm, and then the above-described reaction gas is discharged from the gas blowing unit 5 into the chamber 2. When the reaction gas is introduced into the chamber 2, the blanket W film 24 starts to be deposited on the semiconductor wafer 3, but on the periphery of the semiconductor wafer 3, as shown in FIG. Since the air current is formed upward from the side wall of the semiconductor wafer 3 and toward the center of the semiconductor wafer 3, the reaction gas cannot reach the peripheral edge of the semiconductor wafer 3, and there is almost no growth of the blanket W film 24 on the peripheral edge of the semiconductor wafer 3. .

According to the CVD apparatus 1 and the CVD method described above, the blanket W film 24
The interlayer insulating film 2 on the side wall of the semiconductor wafer 3 which is formed inside the region where the N film 23 is formed and where the TiN film 23 is not formed.
2 does not deposit. Therefore, there is no generation of dust due to poor adhesion between the interlayer insulating film 22 and the blanket W film 24, and there is no possibility that the production yield of the semiconductor device is reduced. Further, there is no micro-peeling caused by the contact between the semiconductor wafer 3 and the shielding plate 9 as in the conventional example, and in the conventional example, the blanket W film 24 formation region on the semiconductor wafer 3 by the shielding plate 9, ie, the semiconductor interior space than the wafer 3 peripheral portion by a distance L ₂ is limited to the semiconductor device formation regions, but the semiconductor device forming region to the semiconductor wafer 3 peripheral portion near widens in the present invention. Therefore, no dust is generated due to the micro-peeling, and the theoretical yield of the semiconductor device can be improved.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the embodiment. For example, although the susceptor of the embodiment is a susceptor having a built-in heater, the chamber may be a quartz chamber, an infrared lamp may be provided from outside the quartz chamber, and the susceptor may be heated by this lamp. Further, although a semiconductor wafer is described as a substrate to be processed, a quartz substrate or a glass substrate may be used. Furthermore, although the description has been made using the blanket W film as the CVD film, the present invention can also be applied to a CVD film such as a high melting point metal film such as Mo or a high melting point metal silicide film. In addition, the shape and material of the guide ring, the width of the purge gas blowing portion, and the flow rate of the purge gas described in the embodiment can be appropriately changed without departing from the technical concept of the present invention.

[0029]

As is apparent from the above description, the CVD apparatus and the CVD method of the present invention make it possible to limit the region where the blanket W film is not deposited to only the vicinity of the periphery of the semiconductor wafer. The generation of particles due to the peeling of the blanket W film can be prevented, the production yield of the semiconductor device can be improved, and the theoretical yield of the semiconductor device can be improved.

[Brief description of the drawings]

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

FIG. 2 is a schematic plan view of a semiconductor wafer mounting portion of the CVD apparatus according to the embodiment of the present invention.

FIG. 3 is an enlarged view of a portion A in FIG. 1;

FIG. 4 is a schematic side sectional view of a conventional CVD apparatus.

FIG. 5 is an enlarged view of a portion B in FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... CVD apparatus, 2 ... chamber, 3 ... semiconductor wafer, 4
... Semiconductor wafer mounting section, 5 ... Gas blowing section, 6 ... Exhaust port, 7 ... Heating heater, 8 ... Susceptor, 8a ... Placement section, 9
... shield plate, 10 ... supporting part, 11 ... gas pipe, 12 ... small hole, 21 ... semiconductor substrate, 22 ... interlayer insulating film, 23 ... Ti
N film, 24: blanket W film, 30: guide ring,
31: gas pipe, 32: purge gas blowing section

Claims (8)

[Claims] 1. A CVD apparatus having a susceptor for mounting and heating a substrate to be processed in a reaction vessel, and a reaction gas discharge unit, wherein the CVD apparatus has a susceptor mounted on the susceptor and a lower portion of a peripheral portion of the substrate to be processed. A purge gas blowing unit is provided, and a guide ring for directing a flow of the purge gas from the purge gas blowing unit to a central upper portion of the processing surface of the substrate to be processed is provided around the peripheral edge of the processing substrate. A CVD apparatus, wherein the CVD apparatus is installed in a plant. 2. The CVD apparatus according to claim 1, wherein the planar shape of the purge gas blowing portion is a ring shape having a shape similar to the shape of the peripheral portion of the substrate to be processed and having a predetermined width. 3. The side wall of the guide ring on the side of the purge gas blow-out portion has a shape similar to the shape of the peripheral edge portion of the substrate to be processed, and the upper surface position of the guide ring is a predetermined distance from the processing surface position of the substrate to be processed. 2. The CVD apparatus according to claim 1, wherein the position between the lower surface and the side surface of the guide ring is a predetermined angle of 90 ° or less. 3. 4. The material of the guide ring is a material having a lower heat absorption rate than the susceptor.
The CVD apparatus according to claim 1. 5. A CVD method using a CVD apparatus according to claim 1, wherein: a step of mounting the substrate to be processed on a susceptor; a step of blowing a purge gas into a reaction vessel from a purge gas blowing section; A CVD method comprising: blowing a reaction gas into the reaction vessel; and depositing a CVD film on a processing surface of the substrate to be processed. 6. The CVD method according to claim 5, wherein the substrate to be processed is a substrate having an interlayer insulating film and a TiN film on a semiconductor substrate. 7. The CVD method according to claim 5, wherein the purge gas is an inert gas. 8. The CVD according to claim 5, wherein the reaction gas is a reaction gas containing WF ₆ gas.
Method.