JP3399124B2 - Method for forming oxide film and apparatus for forming oxide film - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an oxide film on a wafer in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art In the process of manufacturing a semiconductor device, for example, when a flat oxide film is formed on a substrate in a state of filling a gap between wirings formed on the substrate, the film is formed by a CVD method. Is being done. In the above film forming method, for example, tetraethoxysilane (C2H5
O) 4 Si: a gas obtained by vaporizing TEOS), a gas serving as a silicon supply source such as silane (Six H2x + 2: hereinafter SiH4), and a gas serving as an oxidant such as oxygen and ozone. Is used as a reaction gas. Then, for example, each of the reaction gases is supplied in a reduced pressure atmosphere in which a sample is placed,
An oxide film made of silicon oxide is formed on the processed surface of the sample.

According to the above-mentioned method of forming an oxide film, Si is used in the vapor phase.
Decomposition of H4 or TEOS and oxidation reaction proceed to form film-forming molecules, and the film-forming molecules adhere to the surface of the substrate to form a silicon oxide film.

[0004]

However, the above film forming method has the following problems. That is, in the above film forming method, the film forming molecules formed by the film forming reaction in the vapor phase are deposited on the treated surface to form an oxide film. Therefore, for example, film forming molecules are easily trapped at the entrance of the trench, and the step on the substrate surface cannot be sufficiently filled.

Therefore, it is an object of the present invention to provide a method for forming an oxide film which can secure a good filling characteristic.

[0006]

In the method of forming an oxide film of the present invention for achieving the above object, a solution in which a first reaction gas composed of ozone serving as an oxidant is dissolved in a liquid carrier is atomized. And supply in a reduced pressure atmosphere. As a result, an oxide film formed by reacting a plurality of reaction gases including the first reaction gas is formed on the processed surface of the sample placed in the reduced pressure atmosphere. The liquid carrier is water or hydrogen peroxide water.

Further, as the oxidant, in addition to the first reaction gas, oxygen or a second reaction gas containing oxygen and nitrogen may be supplied to the reduced pressure atmosphere in a gaseous state.

[0008]

In the above film forming method, since the solution of ozone, which is the first reaction gas, is dissolved in the liquid carrier is atomized and supplied into the reduced pressure atmosphere, the ozone is unlikely to be a gas even in the reduced pressure atmosphere. Therefore, the deposition reaction of oxidation with ozone is scooped has to the treated surface of the sample. And
By using water or hydrogen peroxide as the liquid carrier, it is possible to prevent contaminants from being brought into the film forming atmosphere.

Further, when oxygen or the second reaction gas composed of oxygen and nitrogen is supplied as the oxidant in a gaseous state into the above reduced pressure atmosphere, the oxide film formed on the treated surface is oxygen-annealed. The quality of the treated oxide film is improved.

[0010]

EXAMPLE A first example of the method for forming an oxide film according to the present invention will be described below with reference to FIG. First, based on FIG.
An example of the apparatus configuration used in the film forming method of the first embodiment will be described. As shown in the figure, the film forming apparatus 6 has a chamber 60 capable of maintaining a reduced pressure inside and a liquid tank 61 for storing the solution 4. Chamber 60 and liquid tank 61
Are connected by a supply pipe 62 for supplying the solution 4 into the chamber 60, and the supply pipe 62 is provided with atomizing means 63.

In the chamber 60, for example, a sample table 66 provided with temperature control means (not shown) capable of cooling and heating.
Are arranged. Further, from above the chamber 60, a gas introduction pipe 65 for introducing the other reaction gas 5 serving as a silicon supply source into the chamber 60 is inserted therein. The tip portion of the gas introduction pipe 65 inserted into the chamber 60 is configured as a diffuser 65a so that the other reaction gas 5 is uniformly supplied to the processing surface 1a of the sample 1.

Further, the liquid tank 61 has the first reaction gas 2
A solution 4 in which ozone (O3) is dissolved in a liquid carrier 3 such as water (H2 O) or hydrogen peroxide solution (H2 O2).
To store. A first gas introduction pipe 64 for supplying the first reaction gas 2 into the liquid tank 61 from above is inserted into the liquid tank 61. Then, the inside of the liquid tank 61 is configured to be maintained at a predetermined gas pressure by the first reaction gas 2 supplied from the first gas introduction pipe 64.

The supply pipe 62 has one end reaching the solution 4 from above the liquid tank 61.
The other end is inserted into the chamber 60. The supply pipe 62 inserted in the chamber 60
Is formed as a diffuser 62a for uniformly supplying the reaction gas to the treated surface 1a of the sample 1, and is disposed between the sample stage 66 and the diffuser 65a of the gas introduction pipe 65. Is located in. The diffuser 62 is formed by molding a tubular body into a ring shape, and a plurality of diffusion holes 62b are provided on the inner surface of the ring shape.

The atomizing means 63 is composed of, for example, an ultrasonic vibrator, and is closely arranged in a state of being wound around the outer wall of the supply pipe 62. This atomizing means 63
May be closely attached to the outer wall of the diffuser 62a without blocking the diffusion hole 62b of the diffuser 62a.

In the film forming apparatus 6 having the above structure, when the solution 4 stored in the liquid tank 61 is supplied into the chamber 60, the solution 4 is atomized by the atomizing means 63 provided in the supply pipe 62. Be converted. Therefore, the first reaction gas 2 is supplied into the chamber 3 60 while being dissolved in the atomized solution 4.

Next, a film forming method using the film forming apparatus 6 will be described with reference to FIG. 2 and FIGS. Here, as shown in FIG. 1A, 8 made of, for example, silicon is used.
1 μm thick on the surface of inch substrate 11 with 0.3 μm spacing
The wafer on which the wiring 12 made of aluminum is formed is used as the sample 1, and the wiring 12 is formed on the processed surface 1 a of the sample 1.
A method of forming a film made of silicon oxide (hereinafter, referred to as an oxide film) in a state of embedding the concavo-convex shape will be described as an example. As the reaction gas used for film formation, ozone (O3) was used as the first reaction gas 2 serving as an oxidant, and silane (Six H2x + 2, hereinafter referred to as SiH4) was used as another reaction gas serving as a silicon supply source. Note) will be used.

First, O 3 used as the first reaction gas 2
Water (H2O) or hydrogen peroxide solution (H2O2)
Is stored in the liquid tank 61 as the liquid carrier 3. Here, H2 O is used as the liquid carrier 3.
Then, O3 is introduced into the liquid tank 61 from the first gas introducing pipe 64 to maintain the inside of the liquid tank 61 at 2 atm, and O3 is dissolved in H2O. Then, the solution 4 formed by dissolving O3 in H2 O is stored in the liquid tank 61. In FIG. 3, 1 atm
3 shows the solubility curve of O3 in H2O at.

Thereafter, the sample 1 is placed on the sample table 66 cooled to -10 ° C to 10 ° C. Then chamber 6
The atmosphere inside 0 is exhausted from the exhaust port 60a, and the chamber 60
The atmosphere inside is kept in a vacuum state of 0.133 mPa or less.

Next, the solution 4 in the liquid tank 61 is caused to flow into the supply pipe 62, and the solution 4 passing through the supply pipe 62 is atomized.
Atomized by 3 and supplied from the diffuser 62a into the chamber 60. At this time, the atomized solution 4 is introduced into the chamber 60 at 5 to 25 g / min. At the same time, SiH4, which is the other reaction gas 5, is flown through the gas introduction pipe 65 at a flow rate of 50 to 150 sccm, and is supplied from the diffuser 65a into the chamber 60. As a result, the film forming atmosphere in the chamber 60 is changed to 110 to 270.
Keep in the range of Pa. Then, as shown in FIG. 1 (2),
An oxide film 13 is formed on the processed surface 1a of the sample 1 by the film forming reaction of the respective reaction gases 2 and 5.

In the method of forming the oxide film (silicon oxide film) 13 , the first reaction gas 2 O 3 is supplied into the chamber 60 in a state of being dissolved in the atomized solution 4. From this, in comparison with the case where the above-mentioned O3 which is an oxidant is supplied into the chamber in the form of gas, O3
The oxidative power in the gas phase decreases. Therefore, it becomes difficult for the film formation reaction of the decomposition and oxidation of SiH4 by O3 to proceed in the gas phase, and the film formation reaction is carried over to the treated surface 1a of the sample 1. Therefore, the film-forming molecules formed in the gas phase are prevented from depositing on the treated surface, and the fluidity at the time of film formation is ensured. Then, an oxide film 13 having good filling characteristics without voids is formed on the treated surface 13.

Next, a second embodiment will be described. The film forming method of the second embodiment is a method of using the same O3 first reaction gas and the second reaction gas as the oxidant as in the first embodiment. The first reaction gas is used by dissolving it in the liquid carrier 3 as in the first embodiment. On the other hand, the second reaction gas is introduced in a gas state into the chamber 60 in a reduced pressure state without being dissolved in the liquid carrier. As the second reaction gas, O3, N2 O, oxygen plasma generated by a generation mechanism not shown, or the like is used. However, the ions contained in the oxygen plasma have low energy of about 10 eV. Further, when the second reaction gas is introduced into the chamber 60, the second reaction gas is prevented from being decomposed and oxidized by the second reaction gas in the vapor phase of the other reaction gas. The flow rate and the supply position in the chamber 60 are set.

In the film forming method of the second embodiment, an oxygen annealing treatment of the oxide film 13 formed on the treated surface 1a is performed by using a gaseous oxidizing agent in addition to O3 dissolved in the liquid carrier. Advances. As a result, the reaction for improving the film quality of the oxide film 13 proceeds, and the oxide film 13 having excellent withstand voltage characteristics is formed.

When the sample temperature at the time of film formation is high, the same effect as above can be obtained by using O2 as the second reaction gas. When the oxide film 13 may be nitrided, plasma of gas containing oxygen and nitrogen may be used as the second reaction gas.

The method of forming the oxide film is not limited to the samples and the film forming conditions shown in each of the embodiments.

[0025]

As described above, according to the film forming method of the present invention, the solution in which the first reaction gas consisting of ozone is dissolved in the liquid carrier is atomized and supplied into the reduced pressure atmosphere, It becomes possible to carry over the film formation reaction of decomposition and oxidation of other reaction gas by ozone to the treated surface of the sample. Therefore, the fluidity at the time of film formation on the treated surface is secured, and a film having excellent embedding characteristics can be obtained. Then, by using water or hydrogen peroxide water as the liquid carrier, it becomes possible to prevent contamination during the film forming process. Further, by supplying a second reaction gas composed of oxygen or oxygen and nitrogen as an oxidizing agent in a gas state in the reduced pressure atmosphere, the oxygen annealing treatment of the oxide film formed on the treated surface proceeds, and the pressure resistance is improved. An excellent oxide film is formed.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a film forming method according to an embodiment.

FIG. 2 is a configuration diagram of an apparatus used in the film forming method of the embodiment.

FIG. 3 is a solubility curve of O3 in H2O.

[Explanation of symbols]

1 sample 1a Sample surface 2 First reaction gas 3 Liquid carrier 4 solution 5 Other reaction gases (reaction gas) 13 Oxide film

Continuation of front page (56) Reference JP-A-4-343456 (JP, A) JP-A-59-87821 (JP, A) JP-A-5-82489 (JP, A) JP-A-3-190229 (JP , A) JP 5-182955 (JP, A) JP 6-295907 (JP, A) JP 3-122281 (JP, A) JP 6-310444 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/31 H01L 21/312 H01L 21/314 H01L 21/316 H01L 21/318 H01L 21/768

Claims (6)

(57) [Claims] 1. A silicon-based compound gas and a first reaction gas serving as an oxidizer are supplied to a reduced pressure atmosphere, and each of the reaction gases is reacted with a treated surface of a sample placed in the reduced pressure atmosphere. In the method for forming an oxide film, the first reaction gas is ozone gas, and the ozone gas is in a state where the solution in which the ozone gas is dissolved in a liquid carrier is atomized to keep -10 ° C to 10 ° C.
A method for forming an oxide film, characterized in that the sample cooled to 0 ° C. is supplied into the reduced pressure atmosphere. 2. The method for forming an oxide film according to claim 1, wherein the liquid carrier is water or hydrogen peroxide water. 3. The method for forming an oxide film according to claim 1, wherein, as the oxidizing agent, oxygen or a second reaction gas containing oxygen and nitrogen is decompressed in addition to the first reaction gas. A method for forming an oxide film, characterized by supplying in an atmosphere in a gaseous state. 4. The acid according to any one of claims 1 to 3.
In the method of forming a chemical film, The silicon compound gas is silane gas.
A method for forming an oxide film as a characteristic. 5. A decompression chamber and a coolable temperature control means arranged in the decompression chamber.
A first gas supply pipe provided with a sample stage provided with the atomization means for atomizing a solution in which ozone gas is dissolved in a liquid carrier, and supplying the solution above the sample stage while maintaining the atomization state. And a second gas supply pipe for supplying a silicon compound gas into the decompression chamber, the oxide film forming apparatus comprising: 6. The atomizing means is an ultrasonic transducer.
The oxide film forming apparatus according to claim 5, wherein.