JPH06168933A - Manufacture of thin film and manufacturing device thereof - Google Patents

Abstract

PURPOSE:To form a thin film at a low temperature and to provide an oxide thin film having good film quality and denseness in combination by a method wherein a reactive physical vapor deposition process, which is accompanied by a chemical reaction with gas containing at least oxygen or the gas discharge plasma, and a reaction process for emitting short-wavelength light on a deposition surface in an atmosphere of gas containing at least a reaction element are alternately repeated plural times. CONSTITUTION:A short-wavelength light source 17 is built in a device container or a container 11, which is movable without breaking a vacuum state therein and is different from the device container, and a thin film deposition process using plasma decomposition in a certain constant time and a process for giving an optical energy to a thin film surface, on which deposition is not performed in a certain constant time, are alternately executed plural times, whereby an oxide thin film of good quality is formed on a low-temperature substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a method for manufacturing a compound thin film such as an oxide by using reactive sputtering and a manufacturing apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, a reactive sputtering apparatus used for forming an oxide crystal thin film has a structure as shown in FIG. 41 is evacuated to a vacuum from the exhaust port 42 in the vacuum chamber. An electric field is introduced from the direct current or high frequency power source 43 into the electrode / raw material target holder 44, and the electric field is applied between the substrate holder / electrode 45 capable of heating the substrate to generate plasma. Reference numeral 46 is a gas introduction port, and when forming an oxide thin film, for example, a sputtering gas such as Ar or a reactive gas for oxidation such as O ₂ is introduced. These gases are decomposed by plasma, ions in the plasma are accelerated and collide with the target 47, and an oxide thin film is deposited and formed on the substrate 48 by so-called sputter deposition. At this time,
When the sputtered active particles reach the substrate, they react with reactive particles such as active oxygen ions and oxygen radicals in the plasma to form an oxide thin film on the substrate.

[0003]

However, in the method using such a conventional reactive sputtering apparatus, when the oxidation reaction is insufficient and a high quality oxide thin film is to be obtained,
It was necessary to extremely reduce the deposition rate and keep the substrate temperature relatively high. Therefore, there are various restrictions such as difficulty in combination with a semiconductor device and device formation on a low melting point substrate, and there are many restrictions in device design and manufacturing process. At present, there is a high demand for formation at lower temperatures.

However, in the conventional method of continuously depositing, as a result, ionic charged particles toward the substrate are impacted by colliding with the film forming surface, and
Good crystal growth and formation of lattices were hindered, and low temperature formation was difficult.

In order to solve the above-mentioned conventional problems, the present invention provides a method for producing a thin film which can realize an oxide thin film having a good number of defects even when the thin film is formed at a low temperature and having good film quality and compactness, and a method thereof. An object is to provide a manufacturing apparatus.

[0006]

In order to achieve the above object, a method for producing a thin film according to the present invention is a method for producing a thin film using a physical vapor deposition means by sputtering a target as a raw material. A reactive physical vapor deposition step involving a chemical reaction with a gas containing or a discharge plasma thereof, and a reaction step of irradiating the deposition surface with short wavelength light in a gas atmosphere containing at least a reactive element,
It is characterized by repeating a plurality of times alternately.

In the above configuration, in the reactive physical vapor deposition process, a mixed gas of a gas involved in a chemical reaction during deposition and an inert gas not involved in the reaction but only involved in sputtering is supplied, In the wavelength light irradiation reaction step, it is preferable to supply only the gas containing the reactive element.

Further, in the above structure, when the reactive physical vapor deposition step and the short wavelength light irradiation reaction step are alternately performed a plurality of times, in both steps, the gas involved in the reaction during the deposition and the reaction are involved. It is preferable to supply a mixed gas of an inert gas that participates only in sputtering without sputtering.

Next, the thin film producing apparatus of the present invention is an apparatus for producing a thin film by using a physical vapor deposition means by sputtering a target as a raw material, and a chemical reaction with a gas containing at least oxygen or its discharge plasma. And a reactive physical vapor deposition means for irradiating the deposition surface with short wavelength light in a gas atmosphere containing at least reactive elements, and means for alternately repeating the both means a plurality of times. And

In the above construction, the short wavelength light source is installed in the same container as the target electrode for causing the sputtering deposition process, or at least the container for performing the sputtering process on the substrate without breaking the vacuum. Alternatively, it is preferable to have a structure that can move between the region and the container or region in which the light irradiation step is performed.

In the above structure, it is preferable to rotate the substrate holder that supports the substrate when moving between the container or region in which the sputtering process is performed and the container or region in which the light irradiation process is performed.

In the above structure, it is preferable to use a light source having a wavelength of at least 150 nm to 300 nm as the short wavelength light source.

[0013]

According to the structure of the present invention, a reactive physical vapor deposition step involving a chemical reaction with a gas containing at least oxygen or its discharge plasma, and a surface on which short wavelength light is deposited in a gas atmosphere containing at least a reactive element. By alternately repeating the reaction step of irradiating the film with a plurality of times, it is possible to obtain an oxide thin film which has few defects even when the thin film is formed at a low temperature and has good film quality and compactness. That is, after the deposition step by reactive sputtering, a step of introducing a gas used for oxidation in a state where the substrate is not exposed to sputtered particles and giving light energy to the surface of the substrate (deposition) by irradiation with short wavelength light is performed. By this process, the first
As a result, the reaction gas in the vicinity of the surface is photoexcited, and in the case of oxygen, for example, a large amount of active atomic oxygen is generated, and the oxygen vacancy portion in the deposited film is compensated by oxygen atoms. In addition, as a second effect, only the extreme surface of the deposited thin film is heated by the irradiation of the short wavelength light source, and the so-called heat treatment effect is great. By repeating these two steps alternately, by sputtering, for example, in the case of an oxide thin film, a dangling bond portion in the formed film is selectively oxygenated and excess oxygen is removed. Has the action of binding to the oxygen and removing it in the form of O ₂ .
After that, the step of forming the film again is repeated.
As a result, even if formed at low temperature, there are few defects as a result,
In particular, it has the function of realizing an oxide thin film having both good film quality and compactness.

Further, according to the structure of the manufacturing apparatus of the present invention, the above-mentioned method of the present invention can be efficiently and reasonably manufactured.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Representative embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a reactive sputtering apparatus capable of performing a light irradiation oxidation treatment shown as an embodiment used in the present invention. A vacuum chamber 11 is evacuated to a vacuum through an exhaust port 12. An electric field is introduced from the direct current or high frequency power supply 13 into the electrode / raw material target holder 14, and the electric field is applied between the substrate holder / electrode 15 capable of heating the substrate to generate plasma. 16 is the first gas inlet,
For example, when a sputtering gas such as Ar or an oxide thin film is formed, a reactive gas such as O ₂ for oxidizing is introduced.
Reference numeral 17 is a light source for irradiating the substrate with short-wavelength light, and the substrate holder 15 is supported by, for example, a shaft 18. By rotating the shaft, the substrate 19 is made to face the target or the light source. Can be done. 20
Is a second gas inlet, and when forming an oxide thin film, for example, only a reactive gas such as O ₂ for oxidizing is introduced near the substrate.

Further, in the apparatus used in this embodiment, the partition 21 is provided in the area where the target is installed and the area where the light source for light irradiation is installed, so that the rotation of the substrate holder is not hindered. Moreover, Ar which is a sputtering gas in the deposition process
And an atmosphere of a mixed gas of O ₂ which is a reactive gas, and an O ₂ gas atmosphere which is a reaction gas in the photoreaction step.

In the first film deposition step, the substrate is placed on the target and the substrate 1 is formed by so-called sputter deposition.
9 is deposited and formed on 9. At this time, when the sputtered active particles reach the substrate, they react with reactive particles such as active oxygen ions and oxygen radicals in the plasma to form a thin oxide film on the substrate. In the process of removing defects in the deposited film, for example, the substrate holder-
The substrate is moved to a region where the sputtered particles do not reach from the target or the deposition rate is extremely low by rotating, and is placed in a region where the light emitted from the light source 17 can be effectively irradiated, and the substrate surface and its vicinity are placed. Let it illuminate. At this time, many active oxygen atoms are generated in the vicinity of the substrate due to photolysis of oxidizing gas molecules such as oxygen molecules,
In addition, due to the heating effect on the surface of the deposition electrode, oxidation of defective portions caused by insufficient oxidation, removal of excess oxygen on the film surface, and thermal relaxation of lattice strain generated in the film are performed. This second step is effective only in a region relatively shallow from the surface of the deposited film, so
There is an optimum condition for the relationship between the time of performing the deposition process of P.O.C. and the time of the light irradiation process. However, by performing these processes alternately, it is possible to damage a dense and high-quality thin film at a relatively low temperature. It can be deposited without forming.

In this embodiment, the gas atmosphere in the deposition process and the photoreaction process is distinguished by having a structure with a partition. However, when there is no partition, it is kept flowing as a mixed gas of Ar and oxygen throughout all the processes. Alternatively, the gas may be alternately switched from the mixed gas to only the oxygen gas or from only the oxygen to the mixed gas in accordance with the rotation of the substrate.

Next, referring to FIG. 2, when the deposition substrate temperature is changed, the sputtering high frequency power density in the first deposition step is set to 0.3 W / cm ² , and a low pressure mercury lamp is used as a light source in the second step. When the amount of light irradiation is constant at 0.5 W / cm ² and the rotation speed of the substrate holder is ² rpm,
The change in relative permittivity of the lead titanate thin film formed with and without light irradiation is shown. In this embodiment, the target has a diameter of 6 inches (about 15 cm), and the time required for the substrate to pass once over the target is about 5 seconds. Under this condition, light is irradiated for about 4 seconds after depositing about 1.5 nm. It is a condition. A clear difference is observed between light irradiation and no light irradiation (rotation is performed), and an improvement in relative permittivity is observed during light irradiation from a substrate temperature lower by 200 ° C. or more than in the case without light irradiation. In the range of the rotation speed of about 1 to 10 rpm, a clear difference was observed between the time of light irradiation and the time of no light irradiation (rotation was performed), but almost no change due to the number of rotations was observed.

As is clear from FIG. 2, it is clear that the dielectric characteristics of the oxide dielectric thin film formed at the low temperature of the substrate are improved by alternately performing the deposition and the light irradiation in the oxidizing atmosphere.

[0021]

As described above, according to the present invention, there is a thin film deposition process in which a short wavelength light source is built in a different container that can be moved without breaking the vacuum and plasma decomposition for a certain period of time. A high quality oxide thin film can be obtained on a low temperature substrate by alternately performing a plurality of steps of applying light energy to the surface of the thin film which is not deposited for a certain period of time.

[Brief description of drawings]

FIG. 1 is a schematic view of a thin film forming apparatus according to an embodiment of the present invention.

FIG. 2 shows the relative dielectric constant of the lead titanate thin film formed with and without light irradiation when the substrate temperature is changed to show the effect of the present invention and the rotation speed of the substrate holder is 5 rpm. The figure which shows the change of a rate.

FIG. 3 is a schematic diagram of a conventional reactive sputtering apparatus.

[Explanation of symbols]

 11 Vacuum Chamber 12 Exhaust Hole 13 DC or High Frequency Power Supply 14 Electrode / Target Holder-15 Electrode / Substrate Holder-16 First Gas Inlet 17 Short Wavelength Light Source 18 Support Shaft 19 Substrate 20 Second Gas Inlet 21 Partition

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuki Komaki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Takashi Hirao 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] 1. A method for producing a thin film using a physical vapor deposition means by sputtering a target as a raw material, a reactive physical vapor deposition step involving a chemical reaction with a gas containing at least oxygen or its discharge plasma. When,
A method for producing a thin film, characterized in that a reaction step of irradiating the deposition surface with short-wavelength light in a gas atmosphere containing at least a reactive element is alternately repeated a plurality of times. 2. In the reactive physical vapor deposition process, a mixed gas of a gas involved in a chemical reaction during deposition and an inert gas not involved in the reaction but only involved in sputtering is supplied to perform short wavelength light irradiation. The method for producing a thin film according to claim 1, wherein only a gas containing a reactive element is supplied in the reaction step. 3. In the step of alternately performing the reactive physical vapor deposition step and the short wavelength light irradiation reaction step a plurality of times, in both steps, the gas involved in the reaction during the deposition and the sputtering are not involved in the reaction. The method for producing a thin film according to claim 1, wherein a mixed gas of an inert gas that participates in is supplied. 4. An apparatus for producing a thin film by using a physical vapor deposition means by sputtering a target as a raw material, a reactive physical vapor deposition means involving a chemical reaction with a gas containing at least oxygen or its discharge plasma. When,
An apparatus for producing a thin film, comprising: a reaction means for irradiating a deposition surface with short-wavelength light in a gas atmosphere containing at least a reactive element, and means for alternately repeating the both means a plurality of times. 5. A short wavelength light source is placed in the same container as the target electrode for causing the sputtering deposition process, or at least the container or region in which the sputtering process is performed without breaking the vacuum. The thin film manufacturing apparatus according to claim 4, wherein the thin film manufacturing apparatus has a structure capable of moving between a container and an area where the light irradiation step is performed. 6. The production of a thin film according to claim 4, wherein when the container or region for performing the sputtering process and the container or region for performing the light irradiation process are moved, the substrate holder for supporting the substrate is rotated. apparatus. 7. A short wavelength light source of at least 150 nm
The thin film manufacturing method according to claim 1, or the thin film manufacturing apparatus according to claim 4, wherein a light source including a wavelength of 300 nm to 300 nm is used.