JPH03177576A - Method and device for cvd - Google Patents

Abstract

PURPOSE:To improve the quality and step coverage of a film without need for a special intricate gas supply system by making a substrate holder movable so that a substrate is intermittently and repeatedly opposed to a gas inlet to a vacuum chamber of a gas inlet system. CONSTITUTION:The vacuum chamber 1 is evacuated, and a gaseous reactant is introduced into the chamber 1 from the gas inlet system. The gaseous reactant is continuously introduced into the chamber 1 from the gas inlets 15 and 19. When the substrate holder 2 is moved and the substrate 4 is placed at a position opposed to the inlets 15 and 19, the gaseous reactant is activated on the substrate surface, and a film is deposited on the substrate 4. After the film is formed in a short time, the holder 2 is moved to separate the substrate 4 from the inlets 15 and 19, the gaseous reaction product on the substrate is sufficiently exhausted, and the gaseous reactant is supplied to the substrate 4. The substrate 4 is again placed at a position opposed to the inlets 15 and 19, and a film is formed. The process is repeated. Consequently, the gas is continuously introduced, and pulse CVD is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a CVD apparatus and a CVD method that improve the method of supplying a reactive gas to a substrate surface.

[Prior Art] In the manufacturing process of silicon monolithic ICs, a silicon oxide thin film formed by CVD is used as an interlayer insulating film.

It is known by engineers in the field that the materials used there, collectively called silicon oxides, include not only pure 5in2 but also 5in2 with oxides such as phosphorus, boron, arsenic, etc. It is widely known. As a starting gas when forming a silicon oxide thin film by CVD, in addition to an inorganic or organic gas for forming SiO□, a starting gas for forming the above-mentioned additive oxide may also be supplied. These are known techniques, such as those published by Noyes, A. Sherman, 1987.
Author, “Chemical Vapor Deposit”
tion for MIcroelectronlcs
Pr1ncIples, Technology.

and applications'', etc.

Hereinafter, in this specification, in order to make the content easier to understand, only the technology for forming a 5in2 thin film as a silicon oxide thin film will be described.
Adding to O2 is an obvious technique, and silicon oxides to which these additive oxides are added can also be formed by the same method.

The most typical starting gas for forming a silicon oxide thin film by CVD is an inorganic silane gas or an organic TEOS gas. Among these, TEOS gas was used in the 1960s, but since the film formation rate is slow and there is a risk of carbon being mixed in as an impurity in the film, silane-based gases, which are inorganic substances, have gradually become mainstream.

However, with the recent progress in miniaturization and high integration of ICs, it is becoming increasingly important to use insulating films that are as flat as possible on top of high aspect ratio lines and spaces, trenches, contact holes, through holes, etc. Forming technology has become extremely urgently needed. On the other hand, it is strongly desired that thin film formation in the IC manufacturing process be performed at a lower temperature than conventionally. In response to such technological trends, there has been a trend to use TEOS gas, which has excellent planarization properties, as a starting gas instead of CVD film formation using a silane-based gas as a starting gas.

Plas7TE is a representative technology that uses TEOS gas as a starting material.
O3-CVD and Oshi:/TEO3-CVD. In the former case, RF discharge is performed in a mixed low-pressure gas atmosphere of TEOS gas, argon or nitrogen gas, and oxygen gas, and 30
A silicon oxide thin film is formed on a substrate controlled at 0 to 400°C. In the latter case, TEOS gas and ozone are supplied to
A silicon oxide thin film is formed on a substrate controlled at 00 to 400°C. In general, the properties of films obtained by plasma TEO5-CVD are close to those of SiO2 films obtained by thermally oxidizing silicon wafers, and are improved over silicon oxide thin films obtained by CVD using silane gas as a starting material. flatness is obtained. On the other hand, ozone TEO
3-CVD provides even better flatness, but
The film contains OH groups, CH groups, and C, and is considered to have insufficient physical properties as an IC interlayer insulating film in terms of durability, impurity content, aging characteristics, etc. ing.

TE01 compared to CVD using silane gas as a starting material
- Although there is no clear explanation as to why the flatness of the silicon oxide thin film is better with CVD,
It is speculated that this is because the TEOS gas travels on the substrate surface for a relatively longer period of time than the silane gas from the time it adheres to the substrate surface until it decomposes into an oxide form.

That is, each TEOS gas molecule has 4 atoms per St atom side.
1 piece for each bond (4 pieces in total) C2H9O
This is probably because it takes a form in which groups (ethoxy groups) are bonded, and it is easier to create conditions that take longer to decompose into Si atoms than with silane gas molecules. Expressing this in another way, in CVD using silane gas molecules, the decomposition and oxidation reactions of the starting gas tend to be spatial reactions.
Furthermore, even if a surface reaction occurs, the distance that surface molecules move until the reaction occurs is small, but CVD by TEOS gas molecules
It can be said that surface reactions are more likely to occur than spatial reactions, and the distance that surface molecules travel until reaction occurs is longer.

However, strictly speaking, only one of the spatial reaction and surface reaction occurs, and it can be assumed that the probability ratio of their occurrence differs depending on the film forming conditions. Probably plasma TEO3-
In CVD, the decomposition and oxidation of TEOS gas in space are
It is thought that this occurs more intensely than in ozone TEO3-CVD, and therefore plasma TEO3-CVD
In D, although the flatness is not as good as the ozone TEO8-CVD film, it appears to result in a more complete oxidation of the film. Also, the film produced by ozone TEO3-CVD is OH, CH.
The reason for containing impurities such as SC is presumed as follows. In ozone TEO3-CVD, the main decomposition and oxidation processes occur through surface reactions. It is thought that TEOS gas or its partial decomposition product gas molecules are incident and attached and deposited. In order to sufficiently eliminate such decomposition product gas molecules and allow the oxidation process to occur completely, it is necessary to apply TE to the substrate surface.
It has been proposed to perform intermittent control of gas supply to the substrate surface, such as temporarily stopping the supply of OS gas and then supplying ozone.

Performing CVD film formation without such gas supply control is called a pulse CVD method.

One of the major advantages of the pulsed CVD method is the effect of improving step coverage when depositing a film inside a fine hole.

It is generally said that films prepared by the CVD method have good step coverage, but if the reaction is not "rate-determining the surface reaction," the step coverage often deteriorates. Even in such a case, step coverage can be improved by using the pulse CVD method. The reason why the step coverage is improved will be explained below using Al-CVD, which is a promising technology for forming a wiring film inside a hole with a large aspect ratio, as an example. Generally, in Al-CVD, the source gas is triisobutylaluminum ((C4H9)3AI) <hereinafter referred to as TIBA. ) to perform thermal CVD. In this case, the following reaction proceeds on the heated surface of the substrate.

(C4T(9) 3 Al → A I +3 C4Ha 10(3/2) H2 That is, from 1 mole of TIBA, 3 moles of 04H8 gas and (
3/2) moles of H2 gas are produced.

Therefore, from the surface of the substrate where the reaction is progressing, a reaction product gas whose volume is about 4.5 times that of the supplied source gas is blown out. Therefore, the raw material gas for continuing the reaction becomes difficult to reach the substrate surface. This tendency becomes noticeable inside holes with a large aspect ratio when the reaction has a tendency to be diffusion-limited to some extent, making it difficult to deposit a film inside the holes. As a result, step coverage deteriorates. In order to prevent this, a method may be used in which the raw material gas is supplied to the substrate surface in a pulsed manner, and then the reaction product gas is sufficiently exhausted. Such a method is CVD of SiC
This has actually been carried out in et al., and it has become possible to fill graphite with a bore distribution of 0.2 to 0.5 μm with SiC.

In the above-described pulsed CVD method, a conventional method for intermittently supplying source gas to the substrate surface has been to open and close a valve at the gas inlet to the reaction chamber.

[Problems to be Solved by the Invention] However, the gas introduction method in the conventional pulse CVD method described above has the following drawbacks.

For example, in the thermal CVD method using TE01 and ozone, TE
In order to reduce the 5i-OH bonds in the film by intermittently supplying 01, the following conditions must be set. In other words, the time for supplying TE01 is relatively short, and TE01 is
Alternatively, the thickness of the intermediate decomposition product of TE01 deposited on the membrane surface should be made as thin as possible, and the subsequent supply of ozone should ensure uniform oxidation over the entire thickness of the deposited film. It won't happen. However,
Since TE01 is a liquid at room temperature, the method usually used is to bubble it with a carrier gas such as an inert gas, vaporize it, and then introduce it into the reaction chamber. Therefore, the vaporized gas of TE01 is released for only a few seconds, and the flow rate is controlled. It is almost impossible to supply water by opening and closing the valve under such conditions. Furthermore, even in the pulsed CVD method using gaseous raw materials, it is extremely difficult to obtain a pulsed gas flow within a few seconds using mass flow controllers that are currently widely used. By the way,
There is also a method to reduce the film thickness in one film deposition by increasing the pulse width and decreasing the flow rate.
This method is not preferred because it reduces productivity.

Furthermore, the conventional pulse CVD method also has the following drawbacks. Introducing a pulsed gas flow into the reaction chamber changes important parameters in the CVD method, such as the total pressure or flow rate within the reaction chamber. To prevent this, it is necessary to introduce an alternative gas so that the total gas flow rate is always constant while the supply of raw material gas is stopped. Or T.E.
When there is a pulsed gas (TE01) and a continuously supplied gas (ozone), such as the CVD method using 01 and ozone, when the pulsed gas is stopped, the flow rate of the continuously supplied gas can be temporarily changed. All you have to do is increase it to . However, in either case, it is unavoidable that a complicated gas supply system is required.

As explained above, in the CV Dri film technology for forming an interlayer insulating film in the IC manufacturing process,
The reason why we were not satisfied with both the flatness of the coating shape and the physical properties of withstand voltage, moisture resistance, and aging characteristics is that
This can be said to be because in the conventional pulse CVD method, the film-forming reaction space is limited to one location, making it difficult to independently control the spatial reaction and the surface reaction.

This invention was developed in view of the current situation, and its purpose is to be able to supply a very short pulsed flow of raw material gas to the substrate surface, and to be able to do so without complicated gas supply. CVD equipment and CV that do not require a system
The purpose is to provide method D.

Another object of this invention is to develop the above-mentioned TE01-CVD technology to provide excellent properties such as good flatness, sufficient oxidation, and low content of OH, CH, and C as impurities. An object of the present invention is to provide a CVD method for obtaining a silicon oxide thin film.

[Means and effects for solving the problem] The invention according to claim 1 includes a vacuum chamber, an exhaust system for evacuating the vacuum chamber, a gas introduction system for introducing a reaction gas into the vacuum chamber, and a substrate holding system. A CVD apparatus including a substrate holder has the following features.

That is, the substrate holder is configured to be movable so that the substrate is intermittently and repeatedly opposed to the gas introduction port into the vacuum chamber of the gas introduction system. The substrate holder undergoes movements such as rotational movement, translational and reciprocating movement. The substrate holder may move continuously while facing the gas inlet, or may temporarily stand still at a position facing the gas inlet.

In this invention, in order to carry out the pulse CVD method, the substrate can be moved intermittently without devising the gas introduction system. To explain the operation of the CVD apparatus of the present invention, after the vacuum chamber is evacuated, a reaction gas is introduced into the vacuum chamber from the gas introduction system. A reaction gas is continuously supplied to the vacuum chamber from the gas inlet.

When the substrate holder moves to a position facing the gas inlet, the reactive gas is activated on the substrate surface and a film is deposited on the substrate. After a short time of film formation, the substrate holder is moved to separate the substrate from the gas inlet, and the reaction generated gas on the substrate is sufficiently exhausted or other reaction gas is supplied to the substrate.

Then, the substrate is again brought to a position facing the gas inlet and film formation is performed, and such operations are repeated thereafter. This allows pulse C to be applied while continuously introducing gas.
The VD method becomes possible. It is also possible to introduce gas intermittently, but in that case as well, the substrate moves after the reaction, so intermittent control of gas introduction does not need to be performed as strictly as in the conventional pulse CVD method.

In addition, as a conventional device, there is a CVD device that has multiple vacuum chambers, each vacuum chamber is connected, and a substrate is transferred to each vacuum chamber using an appropriate substrate transfer mechanism to perform film formation. Such a device is not practical because it takes too much time to move the substrate. It is extremely difficult to repeatedly move the substrate alternately between such vacuum chambers at high speed. On the other hand, the CVD apparatus of the present invention is characterized in that the substrate can be moved at high speed within one vacuum chamber, and a reactive gas can be supplied to the substrate surface for a sufficiently short period of time. Thereby, high productivity can be obtained with a simple device configuration.

The invention according to claim 2 is characterized in that in the CVD apparatus according to the invention according to claim 1, the interior of the vacuum chamber is divided into a plurality of spaces by a partition wall. In this case, a part of the wall surface constituting each space is constituted by a substrate holder, and the substrate holder and the partition wall are separated by a small gap. A gas inlet is opened in at least one of the spaces.

The partition wall in this invention is a space (
This is to separate the space where the gas inlet is open from other spaces. In order to allow movement of the substrate holder, it is necessary to provide a small gap between it and the stationary partition wall. According to this invention, since the reaction gas atmosphere space and other spaces are separated, the reaction gas does not diffuse, and pulse CVD
The law can be effectively implemented.

The invention according to claim 3 is characterized in that in the CVD apparatus according to the invention according to claim 2, two or more of the spaces are each provided with a gas inlet. In this invention, a gas inlet is provided in each divided space, and when two or more types of reaction gases (for example, TE01 and ozone) are used,
Alternatively, it is used when a gas for purging the generated gas is used in addition to the reaction gas.

The invention according to claim 4 is characterized in that, in the CVD apparatus according to the invention according to claim 2, separate exhaust ports are provided in each of the plurality of spaces. This allows the spaces divided by the partition walls to be independently evacuated and the pressure in each space to be independently controlled. Further, the gas in each space is not exhausted through other spaces, and only the necessary gas comes into contact with the substrate, making it possible to perform an ideal pulse CVD method.

The invention according to claim 5 employs a rotating flat plate type substrate holder so that the substrate can be moved alternately through a plurality of spaces.

The invention according to claim 6 employs a rotating drum-shaped substrate holder so that the substrate can be moved alternately through a plurality of spaces. The cross section of the rotating drum perpendicular to the rotation axis is preferably polygonal so that the substrate can be easily attached. A cylindrical drum may also be used if the method of holding the substrate is devised.

The invention according to claim 7 is a CVD method for depositing a film on a substrate by introducing a reaction gas into a vacuum chamber and activating the reaction gas, which has the following features. That is, the film is deposited on the substrate by alternately and repeatedly moving the substrate between a reaction gas atmosphere space and a generated gas exhaust space. According to this invention, when the substrate is in the reactive gas atmosphere space, the reactive gas is activated on the substrate surface and a film is deposited on the substrate, and when the substrate is in the generated gas exhaust space, the substrate surface is The reaction product gas remaining in the tank is exhausted. Then, film formation is performed by moving the substrate alternately between these two spaces.

The invention according to claim 8 is a CVD method for depositing a film on a substrate by introducing a plurality of types of reaction gases into a vacuum chamber and activating these reaction gases, which has the following features. That is, the method is characterized in that a film is deposited on the substrate by alternately and repeatedly moving the substrate between a plurality of spaces having different types of reaction gas atmospheres. According to the invention, when the substrate is in the initial reaction gas atmosphere space,
The first reaction gas is activated on the substrate surface and an intermediate film is deposited on the substrate, and when the substrate is in the next reaction gas atmosphere space, the intermediate film reacts with the next reaction gas to deposit the intermediate film on the substrate. A final film is formed on top.

Then, by moving the substrate alternately between these two spaces, film formation is performed until a predetermined thickness is reached. This invention can also be used when forming a multilayer film. According to the present invention, by alternately moving the substrate between a plurality of reaction spaces to which different reaction gases are supplied, undesirable premature spatial reactions can be suppressed, and the surface diffusion distance of reaction molecules on the substrate surface can be suppressed. is kept sufficiently large so that the starting gas is completely decomposed and oxidized on the substrate surface.

The invention of claim 9 is a specific application example of the invention of claim 8, and by using TEOS gas as one reaction gas and using atomic oxygen generated by inductively coupled high-frequency discharge as another reaction gas. , which is characterized by forming a thin film of silicon oxide on a substrate. That is, in one reaction space, TEOS gas, which is a starting material for silicon, is supplied to the substrate, thereby suppressing the introduction of a gas that may promote undesirable decomposition and oxidation reactions in the space. In another reaction space, atomic oxygen, which has a strong oxidizing effect, is supplied in order to completely carry out the oxidation reaction on the substrate surface.

When supplying the TEOS gas, the TEOS gas molecules are heated in advance before they enter the substrate. The heating temperature is selected at a temperature that does not completely decompose the TEOS gas.

Inductively coupled high-frequency discharge is used to obtain atomic oxygen. Regarding the structure and discharge characteristics of the discharge device for inductively coupled high-frequency discharge used in this invention, for example, (1) Published in 1986, Journal o "Va
Cuum 5lence and Technology
, Volume A4, pp. 475-479.

It, Mlto and 8, Sek1guc old author, “
1nducLIonheated plasIIIa
assIsted chemIcaI vapor
deposltlon ol' SIN” (2) 1
Published in 1988, Vacuum, Volume 31, Pages 271-278,
It is described in ``Characteristics and Applications of High Temperature Nonequilibrium Plasma'' by Hideo Mito and Atsushi Sekiguchi, and these documents also describe the degree of dissociation of molecular gases into atoms. For an example of applying this type of discharge to oxidation reactions, see (3) Japanese Jou, published in 1989.
rnal of Applied Ph1slcs, Volume 28, Pages L952-L954, 5hinjIT
akagl, At5ushl Seklguchl.

Naoklchl llosokawa, Norlo
Terada.

Masatoshi Jo and l1ldeo I
Written by hara.

'''Ba2 Y, Cu3 07-, Oxida
tion by Ther II odynamlc Non
equllllbrlumllllgh-Temperat
ure (TNII) Plasma. Furthermore, regarding an inductively coupled high-frequency discharge discharge device and its application, the following technology related to an application filed by the applicant of the present application is known.

(4) JP-A-61-65420, JP-A-61-91377, JP-A-62-45018, JP-A-62-227089, JP-A-63-166971. Furthermore, regarding this type of technology, There are also applications such as those listed below.

(9) Japanese Patent Application No. 63-163350 (lO) Japanese Patent Application No. 63-278218 (11) Japanese Patent Application No. 63-318147 (12) Japanese Patent Application No. 1-135.67 (13) Japanese Patent Application No. 1-1982 No. 57699 ((4) Japanese Unexamined Patent Publication No. 1-66331) The invention of claim 9 above applies the atomic oxygen generated by the inductively coupled high-frequency discharge according to the prior invention to the formation of a silicon oxide thin film by CVD. , pulse CVD
Provide concrete means for

When forming a silicon oxide thin film using TEOS gas as a starting material, the gas molecules that enter and adhere to the substrate are TEOS gas.
It is currently unclear whether it is most preferable to take the molecular form of Si (OC2H9)4, which is the original form of S gas, or whether it is preferable to take the form of some decomposition intermediate product. In this regard, the inventors believe that an interlayer insulation that is activated or decomposed to some extent rather than the ground state molecular form of Si(OC2H5)4 has better properties. We believe that it is easy to form a film. TEOS gas from 200
Controlled heating to 400° C. does not cause complete decomposition, but can convert the TEOS gas to the preferred form of intermediate products. This intermediate product is produced in one reaction space,
It enters and adheres to a substrate controlled at an appropriate temperature, and diffuses on the film surface.

On the other hand, atomic oxygen, which is another reaction gas, is supplied as follows. That is, by performing high-frequency induction discharge while flowing oxygen gas molecules and setting appropriate RF power, oxygen gas flow rate, and pressure, most of the oxygen gas is converted into atomic oxygen, which is sent into the oxidation reaction space. In the oxidation reaction space, atomic oxygen enters the substrate and reacts with intermediate products of TEOS gas molecules attached to the substrate surface to perform a complete oxidation reaction.

By rotating the substrate holder around the central axis of rotation, the same substrate can be divided into a reaction space where intermediate reaction products of TEOS gas are incident and a reaction space where atomic oxygen is incident and a strong oxidation reaction is performed. By alternating the layers, it is possible to form a silicon oxide thin film with excellent both geometrical flatness and physical properties.

Example] (Example 1) FIG. 1 is a vertical sectional view of an example of the present invention. This device uses TE01 and ozone to coat SiO2 on the substrate.
This is a CVD device for forming a film. 1 is a vacuum chamber, 2
is a substrate holder in which a heater 3 is embedded, and the substrate 4 placed on the substrate holder is heated approximately 50 times.
It is possible to heat up to about 0°C. The entire substrate holder 2 can be rotated by a motor 5 and a power transmission section 6 installed outside the vacuum chamber. The substrate 4 is placed in a recess provided on the substrate holder 2 with its upper end surface in contact with the recess. The inside of the vacuum chamber 1 can be evacuated to a high vacuum by a turbo molecular pump 9 and an oil rotary pump 10 connected via a gate valve 7 and a variable funductance valve 8. 11 is a TEO3 container, cylinder 12, pressure reducing valve 1
3. TEOS gas vaporized by bubbling TE01 with an argon (Ar) carrier gas whose flow rate is controlled through the mass flow controller 14 is supplied to the gas supply port 5.
2 into the vacuum chamber 1.

15 is an inlet for introducing TEOS gas into the vacuum chamber;
It is composed of several gas distribution plates 16 with a large number of holes and a heater section 17 surrounding them. This makes it possible to preheat the TEOS gas.

The structure of this portion is disclosed in JP-A-1-119674 and JP-A-1-198475.

A cylindrical partition wall 18 is provided at the upper end of the gas inlet 15, and the upper end of the partition wall 18 and the lower surface of the substrate holder 2 are separated by a small gap of about 2 mm. Further, an ozone gas inlet 19 having the same structure as the TEOS gas inlet 15 but without a partition wall 18 is installed in the vacuum chamber, and is composed of a gas distribution plate 20 and a heater section 21 .

Ozone gas can be generated by introducing oxygen gas from an oxygen (02) cylinder 22 through a pressure reducing valve 23 into an ozone generator 24 that utilizes silent discharge. The mixed gas of ozone gas and oxygen gas with a concentration of about 8% generated here is flow rate controlled by the mass flow controller 25, and is introduced into the vacuum chamber 1 from the gas supply port 53 through one gas introduction port.

With the space configuration as described above, the upper boundary of the space on the side of the gas inlet 15 is formed by the lower surface of the rotatable substrate holder 2, and similarly, the upper boundary of the space on the side of one gas inlet is also formed.
It will be formed by the lower surface of the rotatable substrate holder 2. Thereby, when the substrate holder 2 rotates, the substrate placed on the lower surface of the substrate holder 2 can be moved between the two spaces.

FIG. 2 is a plan view of the vacuum chamber of the apparatus shown in FIG. 1 viewed from above, showing the relative positional relationship of the substrate 4 and the gas inlets 15, 19 in the vacuum chamber. In this embodiment, four substrates 4 can be placed on the substrate holder 2. Further, gas exhaust is performed in the direction of arrow 30 in the figure, and the exhaust port is installed closer to the gas introduction port 15 of TE01 than the ozone gas introduction 019. By rotating the entire substrate holder 2, the substrate 4 moves as shown by the arrow 31 in FIG.
It faces the S gas inlet 15 and the ozone gas inlet 19.

Next, a procedure for forming a 5iOz film on a substrate using this apparatus will be described. In FIG. 1, first, the inside of the vacuum chamber 1 is evacuated to a high vacuum using the turbo molecular pump 9. Next, the temperature of the substrate 4 is raised to approximately 400°C, and the entire substrate holder 2 is heated to 6 Or
Rotate at a rotation speed of about pm. Next, TEOS gas is introduced into the vacuum chamber by bubbling Ar gas at a flow rate of about 11005 cc through the TEO8 container 11 whose temperature is controlled at 60°C. The TEOS gas is heated to 100 to 200° C. in the gas introduction section 15 before reaching the substrate.

Simultaneously with the introduction of the TEOS gas, a mixed gas of ozone and oxygen generated by the ozone generator 24 is introduced into the vacuum chamber 1 at a flow rate of 3 to 5 SLM. Although one gas inlet port can be heated, if the temperature of this part is raised too much, ozone will decompose and film formation will not be sufficient.

Therefore, in this embodiment using ozone, the heater 2
1 is not used. The pressure inside the vacuum chamber is automatically set to 10 using the pressure horn gauge 26 and the variable funductance valve 8.
It is adjusted to about 0 to 500 Torr. one board 4
During one rotation of the substrate holder 2 (hereinafter referred to as period), the cylindrical partition wall 1 is
8 and faces the gas inlet 15. At this time, the substrate 4 is mainly exposed to the TEOS gas, and a layer of intermediate product of TE01 is formed. During the remaining approximately two-thirds of the cycle, the substrate 4 is in the space on the side of one gas inlet and is mainly exposed to ozone gas, and the intermediate product layer is oxidized.
An in2 film is formed. As a result of evaluating the characteristics of the film created in this way by infrared absorption measurement, the number of Si-OH groups in the film was approximately 8 Pulsed CVD
was found to be sufficiently effective. The partition wall 18 plays a role in ensuring the steepness of gas switching, and without it, the effect of reducing the Si--OH group would be very small.

(Embodiment 2) FIG. 3 is a vertical sectional view of another embodiment of the CVD apparatus of the present invention. The vacuum evacuation system and gas introduction system are the same as those shown in FIG. 1, so they are not shown. Also, vacuum chamber 1, substrate holder 2
, heater 3, substrate 4, motor 5, power transmission section 6, gas inlet 15, 19, etc. are also the same as in FIG. 1, and the same parts as in FIG. 1 are given the same reference numerals. FIG. 4 is a top plan view of the apparatus shown in FIG. 3. The difference between this device and the device shown in Fig. 1 is that the exhaust port for evacuating the vacuum chamber 1 is T.
Exhaust port 50 for EOS gas and exhaust port 51 for ozone gas
They are installed separately. In this embodiment, as shown in FIG. 4, there are two exhaust ports 50.
51 joins outside the vacuum chamber 1, so that both can be evacuated by one vacuum evacuation device. Further, due to the separate provision of the exhaust port, the structure of the partition wall that partitions the vacuum chamber is also different from that of FIG. 1. The partition wall of this embodiment consists of a vertical partition wall 40 for partitioning one of the two gas inlets 15, and an annular horizontal partition wall 41 provided around the side surface of the substrate holder 2. Both partition walls 40 and 41 are installed so as to maintain a slight gap from the substrate holder 2. If there were no horizontal partition wall 41, the two spaces would be in communication on the back side of the substrate holder 2. With the above configuration,
A space dedicated to each gas is formed within the vacuum chamber. TEOS gas is supplied from the gas supply port 52 and the gas supply port 53
By supplying ozone gas from the substrate and following the same procedure as described above, a high quality 5in2 film could be formed on the substrate. The film quality was good, with few Si--OH bonds, as in Example 1.

In this embodiment, since the space for TEOS gas and the space for ozone gas can be exhausted through separate exhaust ports, the TEOS gas is exhausted through the space for ozone gas m, compared to the apparatus shown in FIG. The oxidation reaction using ozone gas can be carried out in a pure manner. Further, by providing variable conductance valves at the exhaust ports 50 and 51, it becomes possible to independently control the pressure in each space.

(Example 3) This example is an example in which an Al--Si alloy film is formed on a substrate using an apparatus similar to that shown in FIG. In this embodiment, triisobutylaluminum (T I BA) is introduced into the gas supply port 52 shown in FIG. 1, and disilane (S t2Hb ) is introduced into the gas supply port 53 shown in FIG.

The film forming conditions are as follows. TIB kept at about 40℃
A is bubbled with Ar gas at a flow rate of about 101005e and supplied to the gas inlet 15. TIBA has gas inlet 1
The TI passing through this part is heated to about 230°C at
BA gas undergoes thermal changes. Furthermore, this gas reaches the substrate heated to about 400° C., and AI is deposited on the substrate due to the final thermal change. On the other hand, one gas inlet is heated to about 20°C. And this gas inlet port 1
By supplying disilane to 9, Si is precipitated on the substrate due to a thermal change similar to that in the case of AI. Rotate the substrate holder as follows. In the embodiment shown in FIG. 1, four substrates were mounted on the substrate holder at the same time, but in this embodiment, the substrates are mounted only at one location.

First, the substrate is held still at a position facing the gas inlet 15 for a few seconds. As a result, approximately 1000 AI films are deposited on the substrate. Next, the substrate boulder is rotated and the substrate is brought to rest facing one disilane inlet. As a substrate with a clean AI film attached, Jinlan easily decomposes and about 20 Si films are deposited in about 5 seconds. The precipitated Si easily diffuses into A1 to form an Al-Si alloy film. By repeating this process ten times, a homogeneous Al5t alloy film is formed. The Si concentration in this film is S
When analyzed by IMS (secondary ion mass spectrometer), approximately 0. It was confirmed that 5% Si was homogeneously present in the film. This film has good characteristics as an IC wiring.

(Example 4) Titanium chloride (Ti
By introducing C14), an Al-Ti alloy film can be formed on the substrate in a similar manner. However, since TiCl4 is a limb at room temperature, a gas supply system similar to that of TE01 and TIBA was also installed upstream of one gas inlet. In this case, the thicknesses of AI and Ti films formed in one film forming process were 500 and 10, respectively. By repeating this film forming process alternately, a homogeneous Al--Ti alloy film was formed on the substrate. Also, the thickness of the AI film is approximately 30o.

By repeating this process about three times with the thickness of the Ti layer being 200 mm, it is also possible to create a multilayer laminated film of Al--Ti. Such a film has a great advantage as an IC wiring material in that hillocks (protrusions on the film surface caused by thermal cycles) are less likely to occur.

(Example 5) As a modification of the CVD method of the present invention, a thin film made of multiple elements such as ternary and quaternary elements was created by dividing the vacuum chamber into three or more parts and providing a gas inlet in each of them. Examples of films that can be formed by such a method include Y-B a-Cu-0 series, B i -
3r-Ca-Cu-0 based oxide superconductor thin film, 5
Examples include dielectric films such as rTiO:+.

(Example 6) An example will be shown in which the step coverage of an AI film was improved by pulse CVD using the CVD apparatus according to the present invention.

TIB from the gas supply port 52 using a device similar to that shown in FIG.
A was introduced by bubbling Ar gas as described above, and Ar gas was introduced from the gas supply port 53. Four substrates 4 were placed on the substrate holder 2 as shown in FIG. Approximately 4
TIBA heated to 0°C was heated with Ar at a flow rate of about 5Qsccm.
The bubbling and vaporized gas is supplied to the gas inlet 15. The gas inlet 15 is heated to about 230° C., where the TIBA gas undergoes a partial thermal change. The temperature of the substrate is set at approximately 400° C., where further thermal changes occur in the TIBA gas and deposit an AI film on the substrate.

The substrate holder 2 was continuously rotated at a speed of about 3 Orpm. While the substrate faces the gas inlet 15, the AI film is formed. -A1 film thickness during film formation is approximately 10
0 to 200 people. While the substrate does not face the gas inlet 15, the surface of the substrate is purged with Ar introduced from one gas inlet at a flow rate of about 508 CCm. As a result, the gas produced by the decomposition of TIBA is sufficiently removed from the substrate surface. Therefore, the substrate 4 is again connected to the gas inlet 15.
When facing the TIBA gas, the TIBA gas can sufficiently reach the bottom of the fine holes, and a film with good step coverage characteristics can be formed. The diameter is 0.8 μm and the depth is 1 μm as described in “2” below.
Attempts were made to form an AI film into the contact hole of
The i-rate (defined as the ratio of the thickness of the film deposited at the bottom of the contact hole to the thickness of the film deposited on the flat part of the substrate) was evaluated. If film formation is performed with the substrate stationary facing the gas inlet 15, the coverage will be 0.
68, whereas when the film was formed by the above pulsed CVD method, the coverage improved to 0.91.

According to this embodiment, the step coverage characteristics can be greatly improved, and it is particularly useful in IC wiring processes and the like. Further, the same effect can be expected even if the gas inlet 19 is simply removed, and in this case, the structure of the device can be simplified by removing one gas inlet.

(Example 7) FIG. 5 is a vertical sectional view of an example of a CVD apparatus equipped with a TEOS gas supply system and an atomic oxygen gas supply system for producing a silicon oxide thin film. Components corresponding to the embodiments shown in FIGS. 1 to 4 are given the same reference numerals.

Reference numeral 1 denotes a vacuum chamber in which a set of substrate holders 2 are attached. The substrate holder 2 has a built-in heater 3, and the substrate 4 attached to its surface can be heated between 300 and 400 degrees.
Can be kept at a suitable temperature of °C. The substrate holder 2 as a whole can rotate around its rotation center axis α.

The substrate holder 2 can be rotated continuously or in steps by a motor 5 and a power transmission section 6 provided outside the vacuum. The substrate 4 is attached to the substrate holder 2 via a stopper 401, and the substrate 4 is arranged perpendicular to the rotation center axis α. The vacuum chamber 1 is evacuated by a pump (not shown). Vacuum chamber 1 has two gas supply systems 100.20
0 supplies the reaction gas. One gas supply system 10
0 is equipped with a TEO5 container 110, and supplies TEOS gas by flowing argon gas at a controlled flow rate from the direction shown by arrow 120 to perform bubbling. T
Since E01 is a wave body at room temperature, arrow 1 is drawn in the heating tank 130.
The vapor pressure is increased by heating to a constant temperature while flowing a circulating heating medium as shown in 31.132. The TEOS gas is transported from the TEOS gas inlet 15 toward the substrate 4 in the direction indicated by an arrow 151 via the valve 111 and the gas supply port 52 . Three gas distribution plates 16 are provided inside the gas inlet 15. Further, a heater 17 is built into the outer peripheral wall of the gas inlet 15, and the temperature of the entire inlet is maintained at an appropriate temperature by a control mechanism (not shown). The gas distribution plate 16 is a metal plate with a thickness of about 1 mm and a diameter of 0.
．． A large number of small holes with a size of about 3 mm are provided to penetrate the metal plate. The TEOS gas is guided into a space surrounded by the gas inlet 15 and the gas distribution plate 16 therein, and is heated to a predetermined temperature while passing through the small holes 161.
When incident on the surface of the substrate 4, it is controlled so that it takes the most preferable intermediate product form. A partition wall 18 is provided in the center of the vacuum chamber.

The gas blown out from the TEOS gas inlet 15 reaches the reaction space 1 surrounded by the wall surface 101 in the vacuum container, the substrate surface of the substrate holder 2, the TEOS gas inlet 15, and the partition wall 18.
50, and is finally exhausted in the direction of arrow 501 via the exhaust port 50 by a pump (not shown).

The other gas supply system 200 connected to the vacuum chamber 1 includes a discharge tube 210 made of quartz and a conduit 220 connected thereto. The quartz discharge tube 210 is composed of an inner cylinder whose inside can be evacuated, and an outer cylinder which cools the inner cylinder from its surroundings. The outer cylinder has a cooling water inlet terminal 212 and an outlet terminal 2.
13, and is operated while flowing cooling water in the directions shown by arrows 2121 and 2131. Quartz discharge tube 2
A coolable copper RF induction coil 211 is further provided around 10, and is connected via an RF type power source impedance matching circuit (not shown). The quartz discharge tube 210 is also provided with an oxygen gas introduction tube 214, through which oxygen gas is supplied with a controlled flow rate in the direction of an arrow 215 from a cylinder (not shown). After closing the cut valve 221 and opening the cut valve 222 to evacuate the inside of the quartz discharge tube 210, the size of the oxygen molecules to be supplied is reduced by flowing oxygen gas and supplying appropriate power from the RF type power source. moieties can be dissociated atomically. Atomic oxygen is supplied through the valve 221 and the gas supply port 53.
The atomic oxygen is transported from one atomic oxygen introduction port toward the substrate 4 in the direction shown by an arrow 191. Atomic oxygen inlet 1
This structure is almost the same as the TEOS gas inlet 15 described above, but unlike converting TEOS gas into a preferred intermediate product form, the effect of heating atomic oxygen does not have much practical significance. Therefore, atomic oxygen does not need to be heated. The gas blown out from a large number of small holes 193 provided in the gas distribution plate 192 (see FIG. 6) of the atomic oxygen inlet 19 is distributed to the wall surface 102 of the vacuum chamber, the substrate surface of the substrate holder 2, and the atomic oxygen inlet. 19 and partition wall 18
is almost confined in the reaction space 190 surrounded by the reaction space 190, and is finally exhausted in the direction of the arrow 511 by a pump (not shown) via the exhaust port 51.

FIG. 6 is a reduced plan view showing the arrangement of two types of gas inlets 15.1 and the partition wall 18 in the vacuum container when viewed from the direction of arrow VI-VI in FIG. When forming a silicon oxide thin film using a CVD apparatus configured as shown in Figures 5 and 6, a method for supplying TEOS gas and atomic oxygen is to continuously flow them simultaneously. There are two methods: one method and one method in which the flow is alternated in time. The latter method will be explained first, followed by the former method.

First, the unprocessed substrate 4 on the substrate holder 2 is placed opposite to the TEOS gas inlet 15, and the T
An intermediate product of EOS gas is made incident on the substrate 4. Next, the valve 111 is closed to stop the supply of TEOS gas, the substrate holder 2 is rotated 1806 times around the rotation center axis α, and the substrate 4 with the intermediate product attached to the surface is inserted into the atomic oxygen inlet 19. Move to opposite position. Then, the valve 221 is opened to supply atomic oxygen while oxidizing the substrate surface. After the oxidation is completed, the valve 221 is closed and the substrate holder 2 is rotated 1800 times around the central axis of rotation again to return to the initial position.

The above is one cycle consisting of the attachment of the TEOS gas intermediate product to the substrate surface and its oxidation reaction. By repeating this cycle, a silicon oxide thin film can be deposited to a desired thickness.

In the method described above, the time during which TEOS gas is supplied and the time during which atomic oxygen is supplied are completely differentiated in one cycle. On the other hand, a slightly more efficient method for depositing silicon oxide is to attach the two substrates 4 to the substrate holder 1 and repeat the cycle described above while constantly supplying TEOS gas and atomic oxygen to the reaction spaces 150 and 190. By repeating this, the reaction can proceed at two locations simultaneously. Therefore, productivity is improved. However, in this latter method, the time the substrate 4 is in one reaction space 150 must be the same as the time the substrate 4 is in the other reaction space 190, so the TE attached to the substrate within a certain time must be
In order to completely oxidize the OS gas intermediate product within the same amount of time, it is necessary to appropriately select the combination of the TEOS gas supply flow rate and the atomic oxygen supply flow rate, which requires precise control. . It is also necessary to have a structure that sufficiently considers measures to prevent gases from other reaction spaces from flowing into the reaction spaces 150 and 190, and to prevent violent spatial reactions from occurring.

If the idea of the latter simultaneous reaction method is further developed, it is possible to consider a method in which the substrate holder 2 is rotated continuously instead of in stepwise rotation. In this case, by appropriately selecting a combination of the flow rates of the TEOS gas and oxygen gas and the rotational speed of the substrate holder, it is possible to form a film that is uniformly oxidized in the thickness direction. FIG. 7 is a reduced plan view showing the arrangement of two sets of gas inlets 15, 19 and the partition wall 18 in the vacuum container, which is suitable for film formation while continuously rotating the substrate holder. In this case, each gas inlet 15, 19 has a substantially semicircular cross-sectional shape, so that the substrate always faces the gas inlet while the substrate holder is continuously rotating.

(Example 8) Figure 8 shows TEOS used to prepare a silicon oxide thin film.
FIG. 3 is a vertical cross-sectional view of another example of a CVD apparatus including a gas supply system and an atomic oxygen gas supply system.

This embodiment differs from the embodiment shown in FIG. 5 in the following points. First, the substrate holder 2 has the shape of a regular hexagonal prism (see also FIGS. 9 and 10). Furthermore, three TEOS gas supply systems and three atomic oxygen gas supply systems are installed in each vacuum vessel 1 (see FIG. 10).

FIG. 9 is a perspective view of the substrate holder 2. FIG. The substrate holder 2 has a large substrate mounting surface 201 parallel to its rotation center axis α, and the substrate 4 is fixed to each surface by a stopper 401.

FIG. 10 is a plan view seen from the arrow direction X-X in FIG.
The arrangement of a vacuum container 1, a substrate holder 2, and six types of gas inlets is shown. The gas inlet of type 6 is TEOS gas inlet 1.
5A, 15B, 15C and atomic oxygen inlets 19A, 19
B and 19C are arranged alternately adjacent to each other. The gas inlet ports are spatially partitioned by six partition walls 8 and connected by a small gap. This creates reaction spaces 150A, 150B, and 150C where intermediate products of TE01 enter the substrate, and space 190A where atomic oxygen enters the substrate and performs an oxidation reaction.

190B and 190C are separated to such an extent that they do not interfere with each other.

As in the case of Embodiment 7 (FIG. 5), in this Embodiment 8, it is possible to supply the TEOS gas and oxygen gas at the same time, or to supply the gas alternately in time. Regarding the gas supply method, it is possible to rotate the substrate holder in steps of about 60'' around its rotation center axis, or to continuously rotate it. In either case, this Embodiment 8 is similar to Embodiment 7. Compared to conventional methods, a large number of substrates can be processed at once, which significantly increases productivity.

It goes without saying that the substrate holder may have a polygonal prism shape other than the hexagonal prism described above, such as an octagonal prism.

Although various embodiments have been described above, the present invention can also be applied to the formation of multilayer laminated films, and possible applications include superlattice devices, compositionally modulated magnetic films, and soft magnetic films for magnetic heads.

[Effects of the Invention] The invention according to claim 1 is configured such that the substrate holder is movable so that the substrate is intermittently and repeatedly opposed to the gas introduction port to the vacuum chamber of the gas introduction system, so that the gas introduction is not performed. Even if it is carried out continuously, the reaction gas can be supplied to the substrate surface in a pulsed manner. This allows pulse C to improve film quality and step coverage characteristics without the need for a particularly complicated gas supply system.
This has the effect of fully utilizing the advantages of the VD method.

In the invention of claim 2, since the inside of the vacuum chamber is divided into a plurality of spaces by partition walls, the reaction gas atmosphere space and other spaces can be separated, and the reaction gas does not diffuse, and the pulse CVD method can be performed. can be implemented effectively.

According to the invention of claim 3, gas inlet ports are provided in two or more spaces, so two or more types of reaction gases can be used,
In addition to the reaction gas, a gas for purging the generated gas can be used.

According to the fourth aspect of the invention, each of the plurality of spaces is provided with a separate exhaust port, so that each space can be independently evacuated and the pressure in each space can be independently controlled. Further, the gas in each space is not exhausted through other spaces, and only the necessary gas comes into contact with the substrate, making it possible to perform an ideal pulse CVD method.

According to a fifth aspect of the invention, a rotating flat plate type substrate holder is employed so that the substrate can be moved alternately among a plurality of spaces.

The invention according to claim 6 employs a rotating drum-shaped substrate holder so that the substrate can be moved alternately through a plurality of spaces, and is particularly suitable for processing a large number of substrates at once.

The invention according to claim 7 provides a pulse CVD method in which a reaction gas is introduced into a vacuum chamber and a film is deposited on the substrate by alternately and repeatedly moving the substrate between a reaction gas atmosphere space and a generated gas exhaust space. This is the invention of claim 1, and the same effect as the invention of claim 1 can be obtained.

The invention of claim 8 is a method for depositing a film on a substrate by introducing a plurality of types of reactive gases into a vacuum chamber and repeatedly moving the substrate alternately between a plurality of spaces having different atmospheres of reactive gases. This is an invention of a pulsed CVD method that allows the pulsed CVD method to be used, and is particularly effective for forming alloy films and multilayer films by the pulsed CVD method.

The invention of claim 9 produces a silicon oxide thin film by using TEOS gas and atomic oxygen as a specific application example of the invention of claim 8, and has the following effects. The process of injecting the silicon starting gas into the substrate as the most preferred intermediate product and the process of decomposition and oxidation on the substrate surface can be independently controlled. Moreover, undesirable spatial reactions can be suppressed. As a result, a silicon oxide thin film with excellent film flatness and physical properties can be obtained.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of the first embodiment of the present invention, Fig. 2 is a plan layout diagram of the first embodiment, Fig. 3 is a vertical sectional view of the second embodiment, and Fig. 4 is the second embodiment. FIG. 5 is a vertical sectional view of the seventh embodiment, FIG. 6 is a reduced plan view seen from the arrow VT-Vl in FIG. 5, and FIG. 7 is a modification of the seventh embodiment. 6 is a reduced plan view similar to FIG. 6, FIG. 8 is a vertical sectional view of the eighth embodiment, FIG. 9 is a perspective view of the substrate holder of the eighth embodiment, and FIG. It is a plan view seen from X. 1... Vacuum chamber 2... Substrate holder 4... Substrate 15. One... Gas inlet 18... Partition wall

Claims (9)

[Claims] (1) In a CVD apparatus comprising a vacuum chamber, an exhaust system for evacuating the vacuum chamber, a gas introduction system for introducing a reaction gas into the vacuum chamber, and a substrate holder for holding a substrate, the vacuum of the gas introduction system is provided. A CVD apparatus characterized in that the substrate holder is configured to be movable so that the substrate is intermittently and repeatedly opposed to a gas introduction port into the chamber. (2) In the CVD apparatus according to claim 1, the inside of the vacuum chamber is divided into a plurality of spaces by a partition wall, and a part of the wall surface constituting each space is constituted by the substrate holder, and the substrate holder and the A CVD apparatus characterized in that the CVD apparatus is separated from a partition wall by a small gap, and the gas introduction port is opened in at least one of the spaces. (3) The CVD apparatus according to claim 2, wherein the gas inlet is provided in each of two or more of the spaces. (4) The CVD apparatus according to claim 2, wherein a separate exhaust port is provided in each of the plurality of spaces. (5) In the CVD apparatus according to claim 2, the substrate holder is rotatable around a rotation center axis, and the substrate can be attached to the substrate holder so as to be perpendicular to the rotation center axis; The CVD apparatus is characterized in that the substrate can alternately pass through the plurality of spaces by rotating the substrate holder. (6) In the CVD apparatus according to claim 2, the substrate holder is rotatable around a rotation center axis, and the substrate can be attached to the substrate holder so as to be parallel to the rotation center axis; The CVD apparatus is characterized in that the substrate can alternately pass through the plurality of spaces by rotating the substrate holder. (7) In a CVD method in which a film is deposited on a substrate by introducing a reactive gas into a vacuum chamber and activating the reactive gas, the substrate is alternately moved between a reactive gas atmosphere space and a generated gas exhaust space. A CVD method characterized by depositing a film on a substrate by moving the substrate. (8) In the CVD method, in which a film is deposited on a substrate by introducing multiple types of reactive gases into a vacuum chamber and activating these reactive gases, between multiple spaces with different types of reactive gas atmospheres. A CVD method characterized by depositing a film on a substrate by alternately and repeatedly moving the substrate. (9) In the CVD method according to claim 8, silicon oxide is formed on the substrate by using TEOS gas as one reaction gas and using atomic oxygen generated by inductively coupled high-frequency discharge as the other reaction gas. A CVD method characterized by forming a thin film.