JP2006278486A - Thin film deposition element and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxide thin film or a nitride thin film deposition element which can maintain the interface property of the oxide thin film by ALD and can highly maintain the substrate certainly, and without a possibility that an ALD high film quality layer which makes an interface with the substrate may be damaged and deteriorated, by utilizing a CVD method without lowering the throughput of depositing. <P>SOLUTION: In the thin film deposition element in which the oxide thin film or the nitride thin film is accumulated on the surface of the substrate, the thin film is composed of three layer structuress of (1) an ALD high film quality layer which is composed of original five or less atomic layers formed by atomic layer vapor phase growth (ALD) on the surface of the substrate, (2) an ALD high-speed depositing layer formed on this ALD high film quality layer, and (3) a CVD layer by plasma CVD formed on this ALD high-speed depositing layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a thin film deposited body in which an oxide thin film or a nitride thin film is deposited on a surface of a substrate and a method for manufacturing the same, and more particularly, a flat made by utilizing atomic layer vapor deposition (ALD). Low-temperature polysilicon TFT (Thin) for panel displays and organic EL (electroluminescence)
The present invention relates to a gate insulating film or an LSI gate insulating film.

TFT gate insulating film for driving the liquid crystal or organic EL consists of SiO _2. An ALD method is used as a method of forming this SiO ₂ film (for example, Patent Document 1). The ALD method has the advantages of high film thickness uniformity and a relatively low formation temperature. Generally, it is said that the film quality is better than the SiO ₂ film formed by the CVD (Chemical Vapor Deposition) method.

JP 2004-47660 A

Although the film quality of the SiO ₂ film formed by the ALD method is surely good, the ALD method forms a film of one atomic layer in the first cycle of the film forming process, and the two atomic layers, 3 A film is formed layer by layer such as an atomic layer. Since the film formed in the first cycle is a film that forms an interface with the substrate, if the formation reaction of this film is insufficient, a dangling bond of Si is formed at the interface between the substrate and the SiO ₂ film. As a result, a residual charge or a reaction with carbon atom C or nitrogen atom N occurs at the interface as fixed electrification. As a result, it becomes a charge trap and an impurity factor, and the electrical characteristics are deteriorated.

  Conventionally, it has not been considered that the film forming the interface with the substrate formed in the first cycle in the ALD method is a particularly important point in electrical characteristics. Therefore, the film quality of the film formed by the ALD method varies.

  An object of the present invention is to ensure that the interface characteristics between an oxide thin film or nitride thin film by ALD and a substrate can be maintained high, and does not reduce the throughput of the film formation. It is an object of the present invention to provide a thin film deposit and a method of manufacturing the same, in which the ALD high-quality film layer that forms an interface with the film does not cause damage and deterioration.

To achieve the above object, according to a first aspect of the present invention, there is provided a thin film deposit formed by depositing an oxide thin film or a nitride thin film on a surface of a substrate, wherein the oxide thin film or the nitride thin film comprises:
(1) an ALD high-quality layer composed of the first five atomic layers or less provided by atomic layer vapor deposition (ALD) on the surface of the substrate;
(2) an ALD high-speed film-forming layer formed on the ALD high-quality film layer;
(3) a CVD layer formed by plasma CVD formed on the ALD high-speed film-forming layer;
This is a three-layer structure.

According to the present invention, the film which is first formed on the substrate surface by the ALD method and forms the interface is an ALD high film quality layer with good film quality. This increase in film quality is achieved by increasing the exposure time to the raw material gas for film formation and the exposure time to the oxidant gas or nitriding gas, that is, by sufficiently increasing the film formation time to reduce unreacted spots. Yes. This improves the quality of the film that forms the interface with the most important substrate and prevents dangling bonds from forming on the Si that forms the substrate, thus preventing the deterioration of the electrical properties of the oxide or nitride thin film. can do.
Thereafter, since the ALD high-speed film formation layer is formed on the ALD high-quality film layer, the film formation speed is low only for the first 5 cycles or less, and the film formation throughput as a whole is greatly reduced. Never do. The high-speed film-forming layer can be formed by shortening the exposure time to the source gas and the exposure time to the oxidizing gas or nitriding gas, that is, shortening the film-forming time. The degree of shortening depends on each case from the viewpoint of whether or not the deterioration can be kept within an allowable range, although the film quality deteriorates due to the increase in speed.
A CVD layer formed by plasma CVD or the like is formed on the ALD high-speed film formation layer, and the film formation can be completed in a short time. When the CVD layer is formed, the ALD high film quality layer is covered and protected by the ALD high speed film formation layer, so that the ALD high film quality layer is not damaged.
That is, the said effect is acquired by the said 3 layer structure.

According to a second aspect of the present invention, there is provided a method of manufacturing a thin film deposit formed by depositing an oxide thin film or a nitride thin film on a surface of a substrate,
(A) forming an ALD high-quality film composed of 5 atomic layers or less on the surface of the substrate over a long period of time required for high-quality film formation in the first 5 cycles or less in atomic layer vapor deposition (ALD);
(B) An ALD high-speed film-forming layer is formed on the ALD high-quality film layer in a high-speed multicycle in a short time per cycle from the ALD high-quality film layer,
(C) The oxide thin film or the nitride thin film has a three-layer structure by forming a CVD layer by plasma CVD on the ALD high-speed film formation layer.
According to the manufacturing method concerning the present invention, the thin film deposit of the 1st mode can be manufactured easily.

According to a third aspect of the present invention, in the second aspect, the source gas for forming an oxide thin film or a nitride thin film in ALD is alkylsilane, alkoxysilane, aminosilane, fluorinated alkoxysilane, halogen silane. It is either of these.
According to a fourth aspect of the present invention, in the second or third aspect, the temperature of the substrate is 50 ° C. to 500 ° C.
According to a fifth aspect of the present invention, in any one of the second to fourth aspects, the source gas content of the oxide thin film or nitride thin film in the reaction vessel in which the formation of the oxide thin film or nitride thin film in ALD is performed. The pressure is 0.1 Torr to 100 Torr, and the partial pressure of the oxidizing gas or nitriding gas is 0.1 Torr to 300 Torr.
Thereby, the thin film deposit of the 1st mode can be manufactured easily and stably. Examples of the oxidant gas include H ₂ O, H ₂ O ₂ , and O ₃ .

  According to the present invention, the interface characteristics between the oxide thin film or nitride thin film by ALD and the substrate can be reliably maintained high, the deposition throughput is not lowered, and the substrate is further obtained by utilizing the CVD method. It is possible to provide a thin film deposited body in which the high film quality layer formed by ALD that forms an interface with the substrate does not have a risk of being damaged or degraded.

Hereinafter, a thin film deposit and a method for manufacturing the same according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an ALD film forming reaction state in a film forming apparatus for carrying out the manufacturing method according to the present invention, and FIG. 2 is a longitudinal sectional view showing a CVD film forming reaction state in the film forming apparatus.
In this film forming apparatus, the reaction vessel 1 includes a heater member 3 for placing the substrate 2 and raising the temperature of the substrate 2, an ALD film forming reaction gas supply port 4, and an ALD film forming reaction gas. A CVD film formation reaction that is supplied to the exhaust port 5, the CVD film formation reaction gas supply port 6, the CVD film formation reaction gas exhaust port 7, and the CVD film formation reaction gas supply port 6. A shower head 9 for uniformly spreading the working gas over the entire film forming surface 8 of the substrate 2 and a plasma generator 10 are provided.
The reaction container 1 is formed in a substantially rectangular parallelepiped shape. And in this Embodiment, the raw material is formed with what alumite-treated aluminum.

In the present embodiment, the substrate 2 is obtained by forming a polycrystalline polysilicon film on a rectangular glass substrate of 370 mm × 470 mm, which serves as a TFT substrate for a flat panel display. The film forming apparatus sets a substrate 2 in a reaction chamber 11 of a reaction vessel 1 and forms a SiO ₂ gate insulating film on the polycrystalline polysilicon film of the substrate 2.

  The heater member 3 on which the substrate 2 is placed is also formed in a rectangular shape in plan view, and the heater member 3 is formed in a large size of about 50 mm on all four sides from the substrate 2. The heater member 3 is made of Inconel 600, and a stainless steel heater (not shown) is built therein.

  The source gas supplied from the ALD film formation reaction gas supply port 4 can be a known ALD film formation reaction gas, and is not limited to a specific type. The ALD film formation reaction gas exhaust port 5 is connected to a turbomolecular pump (TMP) 12 in the present embodiment, and the reaction chamber 11 is sucked and exhausted by the TMP 12.

  The source gas supplied from the CVD film formation reaction gas supply port 6 can also use a known CVD film formation reaction gas, and is not limited to a specific type. The CVD film forming reaction gas exhaust port 7 is also connected to a known suction pump (not shown).

  The shower head 9 has a known structure. That is, a large number of holes (not shown) are provided so that the CVD film formation reaction gas can pass through the large number of holes and uniformly spread over the entire film formation surface 8 of the substrate 2. It has become. The shower head 9 is made of a material obtained by anodizing aluminum.

  The plasma generation unit 10 has a known structure. Specifically, a plurality of round-bar antennas 10 are installed in parallel and spaced apart from each other in a direction intersecting the direction in which the ALD film formation reaction gas flows. ing. Its surface is coated with quartz material.

  Furthermore, the heater member 3 is formed so as to be movable in a direction in which the heater member 3 approaches and separates from the shower head 9 in the reaction vessel 1. The heater member 3 is moved by the moving means 13 in a direction approaching the shower head 9 and a ring-shaped stopper 14 is brought into contact with the peripheral portion of the heater member 3.

  The moving means 13 includes a stainless steel heater column 15, a stainless steel bellows 16 inserted into the heater column 15 and fixed to the bottom surface of the reaction vessel 1, and a substrate heater solidified at the lower end of the heater column 15. A heater 17 is provided, and the heater member 3 can be moved to each position shown in FIGS. 1 and 2 by receiving a driving force of a driving source (not shown).

  The ring-shaped stopper 14 is made of a stainless material so as to make a metal touch with the heater member 3 which is a mating member to be contacted. And the said small volume state (11a of FIG. 1) of the reaction chamber 11 of the reaction container 1 is comprised when the heater member 3 moves and the peripheral part carries out metal touch to the said ring-shaped stopper 14, On the other hand, reaction The large volume state (11 b in FIG. 2) of the reaction chamber 11 of the container 1 is configured by the heater member 3 moving in a direction away from the ring-shaped stopper 14.

  The pressure in the reaction chamber 11a in the small volume state is set to be slightly higher than the adjacent space through the metal touch portion, and it is possible to reliably prevent impurities from entering the reaction chamber 11a from the outside. Can be done.

  Switching between the small volume state (11a) and the large volume state (11b) of the reaction chamber 11 of the reaction vessel 1 by the movement of the heater member 3, an ALD film formation reaction gas supply port 4, and an ALD film formation reaction gas exhaust port. The control unit 20 performs ON / OFF switching of 5, ON / OFF switching of the CVD film forming reaction gas supply port 6 and the CVD film forming reaction gas exhaust port 7, and ON / OFF switching of the plasma generation unit. That is, the control unit 20 causes the reaction chamber 11 of the reaction vessel 1 to have a small volume to perform an ALD film formation reaction, and subsequently changes the reaction chamber 11 of the reaction vessel 1 to a large volume to perform a CVD film formation reaction. It has become.

  Further, the control unit 20 (A) forms a single atomic layer on the surface of the substrate 2 over a long period (0.5 to 5 minutes) per cycle required for high film quality in the first 5 cycles or less in ALD. (B) ALD high-speed film formation on the ALD high-quality film layer 31 at a high-speed multicycle in a short time (about 10 seconds) per cycle from the ALD high-quality film layer 31. A layer 32 is formed, and (C) a CVD layer 33 by plasma CVD is formed on the ALD high-speed film formation layer 32. As a result, the oxide thin film 30 or the nitride thin film has a three-layer structure.

The formation temperature of the oxide thin film or nitride thin film in the reaction vessel 1 for forming the oxide thin film or nitride thin film in ALD is 50 ° C. to 500 ° C., and the source gas partial pressure of the oxide thin film or nitride thin film is The partial pressure of 0.1 Torr to 100 Torr and the oxidizing gas or nitriding gas is 0.1 Torr to 300 Torr. The source gas is any of alkyl silane, alkoxy silane, amino silane, fluorinated alkoxy silane, and halogen silane. Examples of the oxidizing gas include H ₂ O, H ₂ O ₂ , and O ₃ , and examples of the nitriding gas include ammonia gas.

  Next, the operation of the film forming apparatus will be described. The substrate 2 is placed on the heater member 3 in the reaction vessel 1 by a known mechanism (not shown), and the heater member 3 is moved by the moving means 13 until the peripheral edge abuts against the ring-shaped stopper 14. Thereby, the reaction chamber 11 of the reaction vessel 1 is in a small volume state. In this state, the CVD film formation reaction gas supply port 6 and the CVD film formation reaction gas exhaust port 7 are turned off, and the ALD film formation reaction gas supply port 4 and the ALD film formation reaction gas exhaust port 5 are turned on. The ALD film formation reaction gas is sent to the reaction chamber 11a, and an ALD film is formed on the film formation surface 8 of the substrate 2 by the ALD film formation reaction.

  That is, (A) the ALD high film quality layer 31 composed of one atomic layer is formed on the surface of the substrate 2 over the long period (1 minute) per cycle necessary for high film quality in the first 5 cycles or less in ALD. . (B) An ALD high-speed film-forming layer 32 is formed on the ALD high-film quality layer 31 by a high-speed multi-cycle in a short time (about 10 seconds) per cycle from the ALD high-film quality layer 31. As a result, the ALD film formation reaction ends when an ALD film having a desired thickness is formed.

  When the formation of the ALD film is completed, the ALD film formation reaction gas supply port 4 and the ALD film formation reaction gas exhaust port 5 are turned off, and the CVD film formation reaction gas supply port 6 and the CVD film formation reaction The gas exhaust port 7 changes to the ON state. Then, the moving member 13 moves the heater member 3 away from the ring-shaped stopper 14 and stops at the position shown in FIG. Thereby, the reaction chamber 11 of the reaction vessel 1 becomes a large volume state. In this state, the CVD film forming reaction gas is sent to the reaction chamber 11b, and the CVD layer 33 is laminated on the ALD high speed film forming layer 32 of the substrate 2 by the CVD film forming reaction.

  According to the present embodiment, the first film formed on the surface of the substrate 2 by the ALD method to form the interface is the ALD high film quality layer 31 with good film quality. This increase in film quality is achieved by lengthening the exposure time to the raw material gas for film formation and the exposure time to the oxidant gas or nitriding gas, that is, by sufficiently increasing the film formation time to reduce unreacted spots. Yes. As a result, the film quality of the film 31 forming the interface with the most important substrate 2 is improved, and dangling bonds can be prevented from being formed in the Si forming the substrate 2, so that the electrical characteristics of the oxide thin film or nitride thin film can be prevented. A decrease can be prevented.

  Thereafter, since the ALD high-speed film formation layer 32 is formed on the ALD high-quality film layer 31, the film formation speed is slow at most until the first five cycles, and the film formation throughput as a whole is It wo n’t drop that much. The high-speed film-forming layer 32 can be formed by shortening the exposure time to the source gas and the exposure time to the oxidizing gas or nitriding gas, that is, shortening the film-forming time. The degree of shortening depends on each case from the viewpoint of whether or not the deterioration can be kept within an allowable range, although the film quality deteriorates due to the increase in speed.

  FIG. 4 shows the relationship between the Si raw material exposure time per cycle (FIG. 4A) and the oxidizing agent exposure time (FIG. 4B) and the interface order density between the substrate 2 and the interface film after film formation. FIG. It can be seen that the longer the exposure time per cycle for both the Si source and the oxidizing agent, the lower the interface state density of the substrate-film after film formation. A low interface state density corresponds to an improvement in film quality.

  On the other hand, by increasing the exposure time of the Si raw material and the oxidizing agent per cycle, good electrical characteristics can be obtained, but the film formation rate is reduced. Therefore, the exposure time was increased only during the reaction at the substrate-interface. That is, when the Si material exposure time and the oxidant exposure time up to the fifth layer are increased 1 to 100 times or more thereafter, the substrate-film interface characteristics are improved.

  A CVD layer 33 formed by plasma CVD or the like is formed on the ALD high-speed film formation layer 32, and the film formation can be completed in a short time. When the CVD layer is formed, since the ALD high film quality layer 31 is covered and protected by the ALD high speed film formation layer 32, the ALD high film quality layer 31 is not damaged.

Using a 2-inch Si wafer as a base, an SiO ₂ insulating film was formed thereon by ALD. A Si wafer was set in a reaction vessel maintained in a reduced pressure state, and the temperature was raised and maintained at 400 ° C. (1) After supplying the Si raw material gas, (2) performing vacuum exhaust while purging with N ₂ gas, (3) subsequently supplying ozone, and (4) subsequently performing vacuum exhaust while purging with N _2. went. With the above series of flows as one cycle, the film formation was performed for 100 cycles to form a SiO ₂ insulating film having a thickness of 10 nm. A sample formed at this time is A.

Next, up to the fifth layer, the exposure time of both the Si raw material and the oxidizing agent was 50 times that of Sample A, and the other conditions were the same, and a SiO ₂ insulating film was formed. Thereafter, Sample A was manufactured. 99 cycles were carried out under the same conditions as above to produce a SiO ₂ insulating film. Let B be the sample at this time. It was confirmed that Sample B exhibited better interface characteristics and film characteristics than Sample A.

  The present invention relates to a thin film deposited body in which an oxide thin film or a nitride thin film is deposited on a surface of a substrate and a method for manufacturing the same, and particularly to a low-temperature polysilicon for flat panel display and organic EL manufactured using ALD. It can be used as a TFT gate insulating film or an LSI gate insulating film.

It is a longitudinal cross-sectional view which shows the ALD film-forming reaction state in one embodiment which concerns on this invention. It is a longitudinal cross-sectional view which shows the CVD film-forming reaction state in the embodiment. It is sectional drawing of the oxide thin film deposition body which concerns on this invention. FIG. 5 is a diagram showing the relationship between the Si source exposure time per cycle (FIG. 4A) and the oxidant exposure time (FIG. 4B) and the interface state density between the substrate 2 and the interface film after film formation. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reaction container 2 Substrate 3 Heater member 4 Gas supply port for ALD film formation reaction 5 Gas exhaust port for ALD film formation reaction 6 Gas supply port for CVD film formation reaction 7 Gas exhaust port for CVD film formation reaction 8 Film formation surface 9 Shower head 10 Plasma generator 11 Reaction chamber (11a reaction chamber in a small volume state, 11b reaction chamber in a large volume state)
13 Moving means 14 Ring-shaped stopper 20 Control unit

Claims (5)

A thin film deposit formed by depositing an oxide thin film or a nitride thin film on the surface of a substrate,
The oxide thin film or nitride thin film is
(1) an ALD high-quality layer composed of the first five atomic layers or less provided by atomic layer vapor deposition (ALD) on the surface of the substrate;
(2) an ALD high-speed film-forming layer formed on the ALD high-quality film layer;
(3) a CVD layer formed by plasma CVD formed on the ALD high-speed film-forming layer;
A thin film deposit characterized by comprising a three-layer structure. A method for producing a thin film deposit in which an oxide thin film or a nitride thin film is deposited on a surface of a substrate,
(A) forming an ALD high-quality film composed of 5 atomic layers or less on the surface of the substrate over a long period of time required for high-quality film formation in the first 5 cycles or less in atomic layer vapor deposition (ALD);
(B) An ALD high-speed film-forming layer is formed on the ALD high-quality film layer in a high-speed multicycle in a short time per cycle from the ALD high-quality film layer,
(C) A method for producing a thin film deposit, wherein a CVD layer by plasma CVD is formed on the ALD high-speed film formation layer so that the oxide thin film or nitride thin film has a three-layer structure.   3. The raw material gas for forming an oxide thin film or a nitride thin film in ALD is any one of alkyl silane, alkoxy silane, amino silane, fluorinated alkoxy silane, and halogen silane. A method for producing a thin film deposit.   4. The method of manufacturing a thin film deposition body according to claim 2, wherein the temperature of the substrate is 50 to 500.degree.   5. The source gas partial pressure of the oxide thin film or nitride thin film in the reaction vessel in which the formation of the oxide thin film or nitride thin film in ALD is performed in any one of claims 2 to 4 is 0.1 Torr to 100 Torr, A method for producing a thin film deposit, wherein the partial pressure of the oxidizing gas or the nitriding gas is 0.1 Torr to 300 Torr.

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