JP2837087B2 - Thin film formation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma-enhanced chemical vapor deposition (Plasma E) for forming a thin film on a sample surface such as a semiconductor substrate.
The present invention relates to a method for forming a thin film using an enhanced CVD method.

[0002]

2. Description of the Related Art Conventionally, in order to form a thin film on a sample surface such as a semiconductor substrate, a high frequency is applied to a source gas introduced into a reaction vessel to generate plasma, and the source gas is activated. A plasma-enhanced chemical vapor deposition (hereinafter, referred to as PECVD) method for accelerating a chemical reaction and depositing a generated reaction product on a sample surface is widely used.

In particular, a nitride film (SiN film) used as an interlayer insulating film or a wiring protective film (passivation film) between wirings made of Al or an Al alloy has a property of wiring material (500 ° C. or higher due to its low melting point). Cannot be processed at a high temperature), and the formation at a relatively low temperature is required. In this regard, since the PECVD method causes a chemical reaction in a plasma state having high energy, the process is expressed by a significantly lower temperature, for example, 450 ° C. or less, as compared with a high-temperature thermal CVD method requiring a formation temperature of 700 ° C. or more. Becomes possible. Therefore, the PECVD method enables formation of a thin film as an interlayer insulating film or a passivation film, and contributes to improvement in device reliability.

The PECVD apparatus includes a parallel plate electrode type, an induction coil type, a microwave discharge type and the like, and a batch processing type, a continuous processing type, a single wafer type and the like have been developed respectively. In recent years, from the viewpoint of process stability, measures against particles (contaminant particles), etc., a single plate type apparatus of a parallel plate electrode type is becoming mainstream. In addition, the development of a process corresponding to the submicron scale is desired due to the improvement in device integration, and the unevenness of the surface of the thin film affects the coverage of the next formed thin film. Preventing this occurrence is also an important issue because it leads to a decrease in reliability and yield.

[0005]

In recent years, with the demand for higher integration of a large-scale integrated circuit (LSI), PEC
Also in the VD method, development of a technology for forming a finer pattern on a submicron scale has become extremely important. A nitride film used as an interlayer insulating film or a wiring protective film is becoming thinner due to a demand for realizing high integration of a device, and a more dense film quality is required in view of moisture resistance.

On the other hand, a nitride film formed by PECVD is conventionally formed by applying high-frequency power to a source gas system containing SiH ₄ and NH ₃ to form a plasma. After the formation of the desired film thickness, the application of the high-frequency power and the supply of the source gas are sequentially stopped. At this time, Si
Reaction products rich in components are formed at a high film formation rate,
This deposits on the substrate to form an abnormally grown film having large surface irregularities. In a mode in which a nitride film is used as an interlayer insulating film, if this surface irregularity becomes large, the coatability of a subsequently formed wiring thin film such as Al or an Al alloy is deteriorated, and it is difficult to form a wiring pattern by lithography. In addition to this, there is a problem that the disconnection of the wiring or the short circuit between the wirings is caused to lower the yield of the device. Further, even in a mode in which a nitride film is used as a passivation film, there is a problem in moisture resistance and reliability because a normal film thickness cannot be secured due to large surface irregularities.

Further, when the substrate is carried out of the reaction chamber after the completion of the formation of the nitride film, electric charges are accumulated in the substrate and a susceptor on which the substrate is mounted due to plasma discharge, so that electrostatic attraction is prevented. It is assumed that it will happen. This allows
There is also a problem from the viewpoint of reliability of transistor characteristics due to adsorption of particles and the like and charged charges in the film.

The present invention has been made in view of the problems of the conventional PECVD method, and has as its object to provide a method of forming a thin film capable of coping with higher integration and higher reliability of a device. Is to do.

[0009]

According to the thin film forming method of the present invention, the above object is achieved by applying a first power having a high frequency to a source gas in a reaction vessel containing a substrate. Depositing a reaction product in the plasma on the substrate to form a thin film, and applying a second power having a high frequency to the gas containing nitrogen oxides to irradiate the substrate and the thin film with active species in the generated plasma. And the step of performing Alternatively, in a reaction vessel containing a substrate, a first power having a high frequency is applied to a reactive gas containing a fluorine compound, and the inside is cleaned by active species in generated plasma, and a nitrogen compound is included. Applying a second power having a high frequency to the reducing gas to remove residual fluorine components in the reaction vessel by active species in the generated plasma; and applying a third power having a high frequency to the source gas. Depositing a reaction product in the generated plasma on a substrate to form a thin film, and applying a fourth power having a high frequency to a gas containing nitrogen oxides to convert active species in the generated plasma to the substrate and Irradiating the thin film.

[0010]

According to the knowledge of the present inventors, since a nitride film formed by PECVD can be formed at a low temperature of 450 ° C. or less, a thermal nitride film requiring a heat treatment of 700 ° C. or more is not suitable for interlayer insulation. It can also be used for films or passivation films. However, the nitride film formed by the conventional PECVD method has large surface irregularities,
The coatability of the next formed wiring thin film deteriorated, and it was not possible to prevent the disconnection of the wiring or the occurrence of the wiring short.

On the other hand, according to the first thin film forming method of the present invention, the forming step includes depositing a reaction product obtained by a chemical reaction between active species of a raw material gas in a plasma on a substrate. Forming a thin film and irradiating the substrate and the thin film with active species of nitrogen oxides in the plasma. Therefore, active species having strong sputterability generated by nitrogen oxides sputter and smooth the surface irregularities of the thin film, so that even if the next formed thin film is a wiring material such as Al or an Al alloy, it is disconnected or broken. No short circuit occurs, or even if a passivation film is formed next, it will not be partially thinned due to surface irregularities, so that the moisture resistance will not be adversely affected. Moreover,
The active species of nitrogen oxides neutralize the electric charge accumulated on the substrate and the support on which the substrate is mounted, thereby preventing adsorption of particles and the like, and preventing the transistor characteristics from deteriorating due to the electric charges in the film. . Therefore, according to the first thin film forming method of the present invention, it is possible to provide a thin film having a smooth surface and excellent flatness corresponding to high integration of a device, and to greatly contribute to improvement in reliability of device characteristics. .

According to the inventor's knowledge, in the PECVD method for forming a nitride film, a jig such as an electrode inside the reaction chamber or a deposit formed on an inner wall is removed by using a fluorine compound. Is effective, but after performing this fluorine compound cleaning, the deposits remain on the surface from which the deposits have been removed due to bonding via F atoms, and are present in the thin film formed in the next step. However, it was impossible to prevent the film quality of the nitride film itself from deteriorating because it contained a fluorine component.

Therefore, according to the second thin film forming method of the present invention, the cleaning step chemically etches the activated species of the fluorine compound by acting on the deposit formed inside the reaction vessel, and the reduction step includes: By reacting the active species of the nitrogen compound on the residual fluorine component, the bond with the fluorine component is reduced to a bond with a hydrogen bond, and this is removed. Subsequently, the first thin film forming method described above is continued, and proceeds to a film forming step and an irradiation step. Therefore, after cleaning the deposit with the active species of the fluorine compound, the active species of the nitrogen compound are acted on the remaining fluorine component or fluorine bond, thereby removing it as a reaction product containing the fluorine component. , Such as electrodes and jigs, or the surface of the inner wall of the reaction chamber can be activated. Therefore, the step of suppressing the formation of a nitride film containing a fluorine component (having a Si—F—N bond) in the initial stage of film formation after the fluorine compound cleaning, and irradiating active species of nitrogen oxide after the film formation is completed, Since the film is flattened, it is possible to provide a dense nitride film having a uniform film quality over the entire region from the initial stage to the end of the film formation and having a fine-grained surface. Moreover,
The active species of nitrogen oxides neutralize the electric charge accumulated between the substrate and the support on which the substrate is mounted, so that electrostatic adsorption does not occur. Therefore, according to the second thin film forming method of the present invention, it is possible to provide a thin film having a dense film quality corresponding to high integration of a device, a smooth surface and excellent flatness, and a reliability of device characteristics. It can greatly contribute to improvement.

Hereinafter, the present invention will be described in detail.

In the present invention, "nitrogen oxide" includes
A compound containing an N atom and an O atom, which is at room temperature (25
C) is preferred. Specifically, N ₂ O, NO or NO ₂ is preferably used. Among these, N ₂ O is preferable from the viewpoint of flattening the surface irregularities of the film formation and neutralizing the accumulated charge.

In the present invention, the "fluorine compound" is a compound containing an F atom, and is preferably a gas at normal temperature. Specifically, CF ₄ , C ₂ F ₆ or NF ₃ is preferably used. Among these, NF ₃ is preferable from the viewpoint of chemically etching the deposit inside the reaction chamber.

In the present invention, the "nitrogen compound" includes
It is a compound containing N atoms and no O atoms, and is preferably a gas at normal temperature. Specifically, NH ₃ or N ₂ is preferably used. Among them, NH ₃ is preferable from the viewpoint of removing the fluorine component remaining in the reaction chamber.

The thickness of the nitride film formed by the method of the present invention is usually preferably about 0.1 to 1.0 μm.

The reactive gas used in the present invention contains at least the above-mentioned fluorine compound such as NF ₃ , but may contain nitrogen oxide such as N ₂ O or O ₂ as necessary.

The term "reducing gas" used in the present invention refers to a reducing gas capable of converting a Si--F bond to a Si--H bond. In addition to the above-mentioned nitrogen compounds such as NH ₃ ,
H ₄ , N ₂ , H _2, etc. may be included.

Further, the source gas used in the present invention is S
It preferably contains iH ₄ and at least one gas selected from NH ₃ and N ₂ .

The "nitrogen compound" can be used as the carrier gas, if necessary. In the embodiment in which the source gas contains the nitrogen compound, the uniformity of the film thickness can be further improved by the stability of the plasma discharge.

In the present invention, as the reaction conditions other than those described above, for example, the following conditions can be preferably used.

The reaction apparatus usable in the thin film forming method of the present invention includes a reaction vessel for accommodating a substrate, a reactive gas such as a fluorine compound, a reducing gas such as a nitrogen compound, and a raw material gas such as silane. An introduction system that can be introduced into
The reactor is not particularly limited as long as it is a reactor having an electrode for applying a high frequency to these gases. For example, a PECVD apparatus as schematically shown in FIG. 1 is preferably used.

Hereinafter, a schematic configuration of the PECVD apparatus will be described with reference to FIG. Referring to FIG. 1, opposed electrodes 3 and 4 are accommodated in a reaction vessel 2 for realizing a reaction chamber 1 sealed from the outside air. One electrode 4 is held at the ground potential, and a semiconductor substrate 5 for forming a thin film is placed on the opposite surface, and the other electrode 3 receives high-frequency power output from a high-frequency oscillation source 8 for plasma generation. The voltage is applied via an impedance matching circuit 9. In addition, a reaction gas is introduced into the reaction chamber 1 from above the electrode 3 via the pipe 6 and exhausted from the exhaust port of the reaction vessel 2. A heater 7 for controlling temperature is provided on the electrode 4 side.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

In the PECVD apparatus having the structure shown in FIG. 1, the cleaning process of cleaning the inside of the reaction vessel, the reduction process of removing the residual fluorine component, and the film formation of the forming process are performed by the thin film forming method of the present invention. The post-processing process of the process and the irradiation step was performed sequentially.

[0028] shown in the process flow chart 2 of Example 1 Example 1 will be described below for the contents of each process.

(Cleaning Process) In the reaction chamber 1,
NF ₃ or NF ₃ / N ₂ O-based reactive gas is introduced,
A first power having a high frequency is applied thereto from the high frequency oscillation source 8 and activated by the plasma discharge energy to form chemically active radicals of atoms or molecules (active species), and these active particles Is chemically reacted with a deposit formed inside the reaction chamber 1 to perform chemical etching.
Decompression and removal were performed. Below, preferable process conditions are shown.

Pressure: 0.5 to 3.0 [Torr] High frequency: 13.56 [MHz] First power: 500 to 1200 [W] Distance between electrodes: 180 to 999 [Mils] NF ₃ : 100 to 1000 [SCCM] N ₂ O: 100 to 1000 [SCCM] Processing time: 50 to 150 [seconds] Here, NF ₃ which is the main gas of the above cleaning process
Instead, one of CF ₄ and C ₂ F ₆ is preferably used, and the flow rate is preferably about the same as that of NF ₃ .

Further, by the addition of N ₂ O, N ₂
The active species retained from O has the effect of physically etching the deposit, and the chemical action and the physical action work in synergy to more effectively advance the etching, so that the cleaning process time can be reduced.

(Reduction process) Subsequently, the above-mentioned reactive gas and reaction product are decompressed and removed, and the semiconductor substrate 5 previously heated to 25 to 400 ° C. by a halogen lamp outside the reaction vessel 2 is placed in the reaction vessel. 2 was placed at a predetermined location, and NH ₃ / N ₂ -based reducing gas was introduced. A second power having a high frequency is applied thereto from the high frequency oscillation source 8 to cause radicals, which are particles activated by plasma discharge energy, to act on a fluorine component remaining inside the reaction chamber 1 to produce a reaction product. Then, pressure reduction and removal were performed. The process conditions are described below.

Pressure: 1.0 to 6.5 [Torr] High frequency: 13.56 [MHz] Second power: 100 to 800 [W] Substrate temperature: 300 to 400 [° C] Distance between electrodes: 180 to 600 [Mils] NH _3: 50 to 1500 [SCCM] N _2: 500 to 2000 [SCCM] processing time: the 5-60 (seconds) wherein said reducing gas, only NH ₃ one type is preferably used . Further, results in a plasma stability of the reduction process by the addition of a preferred amount of N _2.

(Film Forming Process) Further, the above-mentioned reducing gas and reaction products were decompressed and removed, and a SiH ₄ / NH ₃ / N ₂ source gas was introduced while the substrate was mounted.
A third power having a high frequency is applied to this from the high frequency oscillation source 8 and activated by the plasma discharge energy to decompose a chemical bond to form an atomic or molecular radical. The reaction product between these active particles was deposited on the surface of the semiconductor substrate 5 and reduced in pressure and removed while forming a nitride film. The process conditions are shown below.

Pressure: 3.0 to 6.5 [Torr] High frequency: 13.56 [MHz] Third power: 100 to 800 [W] Substrate temperature: 300 to 400 [° C] Distance between electrodes: 180 to 600 [Mils] SiH _4: 50 to 300 [SCCM] NH _3: 50 to 300 [SCCM] N _2: 500 to 5000 [SCCM] processing time: 10 to 100 (seconds) (post-treatment process) Next, N ₂ An O or N ₂ O / O ₂ system post-treatment gas is introduced, and a fourth power having a high frequency is applied to the post-treatment gas from the high-frequency oscillation source 8 to be activated by the plasma discharge energy, thereby obtaining a chemically active gas. These active particles are radiated to the semiconductor substrate 5 and its support base as strong atomic or molecular radicals. Radicals generated from N ₂ O have a sputter property, so that the surface irregularities of the formed thin film are smoothed by sputtering.
Further, the irradiated N ₂ O and its radicals neutralize the electric charge of the semiconductor substrate and its support accumulated by the above-mentioned process. Therefore, conventionally, when the substrate is carried out of the reaction chamber, the substrate does not separate from the support table due to electrostatic adsorption.
Or, even if they are separated from each other, there is no problem such as displacement or break of the substrate. Below, preferable process conditions are shown.

Pressure: 0.5 to 5.0 [Torr] High frequency: 13.56 [MHz] Fourth power: 50 to 500 [W] Substrate temperature: 300 to 400 [° C] Distance between electrodes: 180 to 999 [Mils] N ₂ O: 100 to 1000 [SCCM] Processing time: 1 to 15 [sec] The film forming rate of the nitride film obtained under these conditions is 0.2 to
At 1.0 μm / min, the refractive index was 1.9 to 2.2.

Second Embodiment FIG. 3 shows a process flowchart of the second embodiment, and the contents of each process will be described below.

(Cleaning Process) In the reaction chamber 1,
NF ₃ or NF ₃ / N ₂ O-based reactive gas is introduced,
A first power having a high frequency is applied thereto from the high frequency oscillation source 8 and activated by the plasma discharge energy to form chemically active radicals of atoms or molecules (active species), and these active particles Is chemically reacted with a deposit formed inside the reaction chamber 1 to perform chemical etching.
Decompression and removal were performed. Below, preferable process conditions are shown.

Pressure: 0.5 to 3.0 [Torr] High frequency: 13.56 [MHz] First power: 500 to 1200 [W] Distance between electrodes: 180 to 999 [Mils] NF ₃ : 100 to 1000 [SCCM] N ₂ O: 100 to 1000 [SCCM] processing time: 50 to 150 (seconds) where the place of the NF _3, CF ₄ and C ₂ F ₆
Is preferably used, and the flow rate is NF ₃
The same degree as that described above is preferably used.

The effect obtained by adding N ₂ O is the same as that of the first embodiment.

(First Reduction Process) Subsequently, the above-mentioned reactive gas and reaction product are reduced in pressure and removed, and NH ₃ / N
_Two types of reducing gas were introduced. A second power having a high frequency is applied thereto from the high frequency oscillation source 8 to cause radicals, which are particles activated by plasma discharge energy, to act on a fluorine component remaining inside the reaction chamber 1 to produce a reaction product. And removed by evacuation. Where N
Instead of H ₃ / N ₂ reducing gas, NH ₃ or Si
An H ₄ / N ₂ / NH ₃ gas is preferably used. The process conditions are described below.

Pressure: 1.0 to 6.5 [Torr] High frequency: 13.56 [MHz] Second power: 100 to 800 [W] Substrate temperature: 300 to 400 [° C] Distance between electrodes: 180 to 600 [Mils] SiH _4: 50 to 300 [SCCM] NH _3: 50 to 1500 [SCCM] N _2: 500 to 2000 [SCCM] processing time: in embodiments of the 5-15 (second) reducing gas containing SiH ₄ is to form a reaction product having a bond residual fluorine component by the above-mentioned cleaning process SiH ₃ ⁺ obtained by plasma, Si-F-N formed by combining the SiH ₃ ^*, etc. active species, which Can be removed outside the reaction chamber by controlling the pressure so as not to deposit. Therefore, a synergistic effect is brought about in addition to the reducing effect by NH ₃ .

(Second Reduction Process) Further, the above-mentioned reducing gas and reaction products are decompressed and removed, and the semiconductor substrate 5 previously heated to 25 to 400 ° C. by a halogen lamp outside the reaction vessel 2 is reacted. It was placed at a predetermined place in the container 2 and NH ₃ or NH ₃ / N ₂ -based reducing gas was introduced. A third power having a high frequency is applied thereto from a high frequency oscillation source 8 to cause radicals, which are particles activated by plasma discharge energy, to act on a fluorine component remaining inside the reaction chamber 1 to produce a reaction product. And decompression
Removal was performed. The process conditions are described below.

Pressure: 1.0 to 6.5 [Torr] High frequency: 13.56 [MHz] Third power: 100 to 800 [W] Substrate temperature: 300 to 400 [° C] Distance between electrodes: 180 to 600 [Mils] NH _3: 50 to 1500 [SCCM] N _2: 500 to 2000 [SCCM] processing time: 5 to 60 thereby (seconds), the surface of the semiconductor substrate 5 is also uniformly activated,
A favorable tendency is obtained in which the nitride film formed in the next film forming process is formed uniformly.

(Film Forming Process) Further, the above-mentioned reducing gas and reaction products were decompressed and removed, and a SiH ₄ / NH ₃ / N ₂ source gas was introduced while the semiconductor substrate 5 was mounted. A third power having a high frequency is applied to this from the high frequency oscillation source 8 and activated by the plasma discharge energy to decompose a chemical bond to form an atomic or molecular radical. The reaction product of these active particles was deposited on the surface of the semiconductor substrate 5 and removed under reduced pressure while forming a nitride film. The process conditions are described below.

Pressure: 3.0-6.5 [Torr] High frequency: 13.56 [MHz] Third power: 100-800 [W] Substrate temperature: 300-400 [° C] Distance between electrodes: 180- 600 [Mils] SiH _4: 50 to 300 [SCCM] NH _3: 50 to 300 [SCCM] N _2: 500 to 5000 [SCCM] processing time: 10 to 100 (seconds) (post-treatment process) Next, N ₂ An O or N ₂ O / O ₂ system post-treatment gas is introduced, and a fourth power having a high frequency is applied to the post-treatment gas from the high-frequency oscillation source 8 to be activated by the plasma discharge energy, thereby obtaining a chemically active gas. These active particles are radiated to the substrate and its support base as strong atomic or molecular radicals. Radicals generated from N ₂ O have a sputter property, so that the surface irregularities of the formed thin film are smoothed by sputtering. Also,
The irradiated N ₂ O and its radicals neutralize the electric charge of the semiconductor substrate 5 and the support thereof accumulated by the above-described process. Therefore, conventionally, there is no problem that the substrate does not separate from the support table due to electrostatic attraction when the substrate is carried out of the reaction chamber, or the substrate is displaced or cracked even if the substrate is separated. Below, preferable process conditions are shown.

Pressure: 0.5 to 5.0 [Torr] High frequency: 13.56 [MHz] Fourth power: 50 to 500 [W] Substrate temperature: 300 to 400 [° C] Distance between electrodes: 180 to 999 [Mils] N ₂ O: 100 to 1000 [SCCM] Processing time: 1 to 15 [sec] The film forming rate of the nitride film obtained under these conditions is 0.2 to
At 1.0 μm / min, the refractive index was 1.9 to 2.2.

Deposits in the reaction vessel 2 and the reaction chamber 1 which have been cleaned are removed by the fluorine compound radical, and the fluorine component remaining in these is reduced to hydrogen by the action of NH ₃ radical. 2 and the surface of the components in the reaction chamber 1 are activated. Therefore, generation of particles (contaminant particles) during the process of forming a nitride film on the semiconductor substrate 5 is suppressed, and a stable film formation rate and its distribution are realized. In addition, since a nitride film containing a fluorine component is not formed at the beginning of the forming process, even if the underlying substrate is formed on a wiring such as Al or an Al alloy, the adhesion is high and peeling does not occur. In addition, N ₂ O and its radicals neutralize the electric charge accumulated on the substrate and its support, prevent electrostatic adsorption of particles and the like, and neutralize the charge of the device region including the formed film. Accordingly, the semiconductor substrate 5 after the process is completed is formed with a nitride film having a smooth surface and excellent flatness corresponding to high integration of the device, and a device having no damage to the transistor characteristics and having no damage. It is transported outside.

COMPARATIVE EXAMPLE Here, the Vfb value by CV measurement was used to determine how much the charge accumulated on the substrate was reduced by the post-treatment process using the N ₂ O-containing gas plasma in the thin film forming method of the present invention. (Table 1).

Table 1: Example of voltage measurement using transistors

[0051]

[Table 1]

According to this, when there is no post-processing process, the Vfb values at the center and the periphery of the semiconductor substrate were -9.41 [V] and -3.11 [V], respectively. If there is a post-processing process,
4.02 [V], -2.77 [V], greatly reduced,
The distribution in the plane was also small and uniform.

[0053]

As described above, according to the method for forming a thin film of the present invention, the forming step includes forming a thin film by depositing a reaction product on a substrate, and irradiating the thin film with nitrogen oxide. The active species is irradiated on the substrate and the thin film.
Therefore, active species having strong sputterability generated by the nitrogen oxides flatten the surface of the thin film by sputtering, so that even if the next formed thin film is a wiring material such as Al or an Al alloy, disconnection or No short circuit occurs, or even if a passivation film is formed next, it will not be partially thinned due to surface irregularities, so that the moisture resistance will not be adversely affected. In addition, the active species of nitrogen oxides neutralize the electric charge accumulated on the substrate and the support on which the substrate is mounted, preventing electrostatic adsorption of particles and the like, and preventing the reliability of the transistor characteristics from deteriorating due to the electric charge in the film. I can do it. Therefore, it is possible to provide a method for forming a thin film which has a smooth surface and is excellent in flatness and which contributes to improvement in device reliability, which is compatible with high integration of devices.

Further, before the forming step, the inside of the reaction vessel is cleaned by etching based on plasma of a fluorine compound by performing the above-described cleaning step and reduction step in advance. By adding a step of reacting on the basis of the plasma and reducing in a form in which a reaction product containing a fluorine component is formed, the surface of the component contained in the reaction vessel is activated, and the fluorine component is reduced during the film formation. Not included. Therefore, the formed nitride film can have a high-density film quality with strong Si-N bonds from the beginning to the end of film formation, and has a moisture resistance even when used as an interlayer insulating film or a passivation film. An excellent nitride film can be formed. Moreover, the nitride film containing no fluorine component has excellent adhesion, and does not peel (peel) even when the underlying substrate is formed on a wiring such as Al or an Al alloy. Therefore, a nitride film can be formed with a high product yield. As a result, it is possible to provide a method for forming a thin film that can cope with high integration and high reliability of a device.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a schematic configuration of a PECVD apparatus for explaining an embodiment of a thin film forming method according to the present invention.

FIG. 2 is an explanatory view of a process flow according to a preferred embodiment 1 of the present invention.

FIG. 3 is an explanatory view of a process flow according to a preferred embodiment 2 of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reaction chamber, 2 ... Reaction container, 3/4 ... Counter electrode, 5 ... Semiconductor substrate, 6 ... Piping, 7 ... Heater, 8 ... High frequency power supply, 9
... Impedance matching circuit.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuo Urata 14-3 Shinizumi, Narita City, Chiba Prefecture Inside the Nogedaira Industrial Park Inapplied Materials Japan Co., Ltd. Nogedaira Industrial Park Applied Materials Japan Co., Ltd. (56) References JP-A-3-166372 (JP, A) JP-A-7-183224 (JP, A) JP-T1-502065 (JP, A) (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/31 H01L 21/316 C23C 16/50

Claims (6)

(57) [Claims] A step of applying a first high-frequency power to a source gas in a reaction vessel containing a substrate to deposit a reaction product in a generated plasma on the substrate to form a thin film; Applying a second high-frequency power to a gas containing nitrogen oxides under a pressure of 5.0 torr to irradiate the substrate and the thin film with active species in generated plasma. 2. A step of applying a first high-frequency power to a reactive gas containing a fluorine compound in a reaction vessel containing a substrate and cleaning the inside with a reactive species in generated plasma, the method including a nitrogen compound. Second for reducing gas
Applying a high-frequency power to remove the residual fluorine component in the reaction vessel with the active species in the generated plasma; and applying a third high-frequency power to the raw material gas to generate a reaction product in the generated plasma. Depositing a thin film on the substrate, applying a fourth high-frequency power to a gas containing nitrogen oxide under a pressure of 0.5 to 5.0 torr, and activating the active species in the generated plasma with the substrate and Irradiating the thin film. 3. The method of claim 1, wherein said nitrogen oxide is N ₂ O.
Or the method for forming a thin film according to 2. 4. The thin film forming method according to claim 2, wherein said fluorine compound contains at least one compound selected from NF ₃ , CF ₄ and C ₂ F ₆ . 5. The method according to claim 2, wherein the nitrogen compound is NH ₃ . 6. The method according to claim 1, wherein said source gas is SiH ₄ , NH ₃ and N
_2. A gas containing at least one kind of gas selected from ( ₂ ).
6. The method for forming a thin film according to any one of items 5 to 5.