JPH056880A - Surface treatment method - Google Patents

Abstract

PURPOSE:To provide a surface treatment method wherein halogens which are left on the surface of a semiconductor or a metal can be removed simply. CONSTITUTION:In a surface treatment method wherein a spontaneous oxide film and a halogen contaminant layer on the surface of a substrate to be treated are removed, an Al alloy thin film 22 is formed on an Si substrate 20 via a thermal oxide film 21. The method is featured in the following manner: regarding the substrate, to be treated, wherein a CVD oxide film 23 having an opening in one part on it, a spontaneous oxide film 25 formed on the surface of the Al alloy thin film 22 is removed by using BCl3, gas; after that, 2H6, gas is brought into contact with the surface of the substrate to be treated without exposing the substrate to the air; a halogenide layer 26 which contains B and lis removed; and a W thin film 27 is formed selectively on the Al alloy thin film 22 without exposing the substrate to be treated to the air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor element manufacturing technique, and more particularly to a surface treatment method for removing halogen remaining on a surface by a treatment process using a gas containing a halogen element.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, it is a problem that a natural oxide film is formed on the surface of a semiconductor such as Si or a metal such as Al. For example, when a film is deposited on a semiconductor on which a native oxide film is formed, the quality of the resulting film is inferior to that of a film formed by removing the native oxide film, and the contact resistance between the film and the underlying layer is increased. . Even in a selective process such as selective CVD in which a thin film is selectively deposited between a semiconductor and an insulator, if a natural oxide film that is an insulator is formed on the surface of a semiconductor, the selectivity of CVD is lowered.

Therefore, various methods for removing the natural oxide film have been recently studied. Even if the natural oxide film is once removed, it is reformed when exposed to the atmosphere. Therefore, attempts have been made to remove the natural oxide film by dry etching in a vacuum or an inert gas atmosphere. Most of them use active species containing a halogen element. For example, in the case of a natural oxide film of Si, plasma etching or downflow etching of a gas containing a fluorine element such as CF ₄ or SF ₆ , HF
Solids and liquids containing gas and HF (NH ₄ F, HSO ₃ F
Et al .; generated by condensation of gas) is proposed. However, when the natural oxide film is removed by using such active species containing a halogen element, halogen remains on the surface because the surface after the natural oxide film is removed is active. That is, a semiconductor halide layer is formed on the semiconductor surface, and like the natural oxide film, this halide layer also causes deterioration of the film quality of the deposited film, increase of electric resistance, deterioration of selectivity of the selection process, and the like.

Further, the halogen remains on the wall surface of the reaction vessel in which the treatment using the halogen gas is performed, vacuum parts such as a valve for handling the halogen gas, and metal surfaces such as pipes. The halogen reacts with moisture. As a result, acid is generated and the metal surface is melted to cause a leak.

[0005]

As described above, conventionally, when the halogen gas is used for the treatment, the halogen remains on the surface of the semiconductor or the metal, but the halogen reacts with the water to generate an acid and disconnects the metal wiring. However, there are problems such as deterioration of the film quality of the film formed thereon, and increase of contact resistance. Further, there is a problem in that the halogen remaining in the processing device corrodes the reaction container, the vacuum parts, the piping, etc., and causes a leak.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a surface treatment method capable of easily removing halogen remaining on a semiconductor or metal surface. .

[0007]

The essence of the present invention is to remove the halogen remaining on the surface of the object to be processed by supplying gas or irradiating an electron beam.

That is, according to the present invention (claim 1), CO gas, NO gas, and hydrogen elements, CO, and NO in the molecule are formed on the surface of the object to be processed which has undergone the processing step using a gas containing at least a halogen element. It is characterized in that a gas containing at least one of the compound gases containing at least one is brought into contact to remove the halogen remaining on the surface of the substrate to be treated.

Further, according to the present invention (claim 2), the natural oxide film formed on the surface of the substrate to be processed is removed by using a gas containing at least a halogen element, and then the surface of the substrate to be processed is exposed without being exposed to the atmosphere. CO gas, NO gas, and a gas containing at least one compound gas containing at least one of hydrogen element, CO, and NO in the molecule are brought into contact with each other, and then the surface of the substrate to be treated is exposed to the atmosphere without exposing the substrate to the atmosphere. It is characterized in that a predetermined thin film is formed.

Further, according to the present invention (claim 3), the surface of the object to be processed which has undergone the processing step using a gas containing at least a halogen element is irradiated with an electron beam to remove the halogen remaining on the surface of the substrate to be processed. It is characterized by

Preferred embodiments of the present invention include the following (1) to (10). (1) The treatment step using a gas containing a halogen element is a treatment for removing the natural oxide film of the metal or semiconductor formed on the surface of the substrate to be treated, or the metal, semiconductor, or the metal formed on the surface of the substrate to be treated. It is an etching process for organic substances and insulating films. (2) The surface of the substrate to be processed is the surface of a semiconductor or a metal used for forming a semiconductor element, or the surface of a vacuum component, a reaction container, or a gas pipe exposed to a gas containing a halogen element.

(3) The compound molecule containing a hydrogen element is B _x H
_{x + 4} , B _x H _{x + 6} , B _x C ₂ H _{x + 2} , C _x H _2x-2 , C _x
H _2x, C _x H _{2x + 2} , NH ₃ , NHR ₁ R ₂ (R ₁ , R _{2
= C x H y), N} 2 H 4, Si x H 2x + 2, PH 3, H 2
S, Ge _x H _{2x + 2} , AsH ₃ , HCN, CsH, or HI. (4) The compound molecule containing CO is any one of C ₃ O ₂ , carbonyl compound and carboxylic acid. (5) compound molecules containing NO is the N _x O _y.

(6) When the electrically neutral gas is brought into contact with the surface of the substrate to be treated, the surface of the substrate to be treated is subjected to heating, electron beam irradiation, or light irradiation. (7) In (6), when the heat treatment is performed, the substrate to be treated is heated to a temperature at which the electrically neutral gas is thermally dissociated or higher. (8) In (6), when irradiating an electron beam or light,
An electron beam or light having an energy higher than the dissociation energy of an electrically neutral gas is used. (9) In (6), light is light which is not absorbed by an electrically neutral gas and has energy higher than the work function of metal or semiconductor. (10) In the thin film forming process, W selection using WF ₆ gas C
It is VD.

[0014]

According to the present invention, by using the above-mentioned gas, the halogen remaining on the semiconductor or metal surface can be reduced and removed. As a result, it is possible to suppress the corrosion of the metal wiring, improve the film quality of the thermal oxide film or the crystal, increase the selectivity of high selective CVD or high selective etching, and form a film with low contact resistance. It is also possible to suppress corrosion of vacuum parts and pipes that use halogen gas.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. (First embodiment)

FIG. 1 is a sectional view showing a schematic structure of a surface treatment apparatus used in the method of the first embodiment of the present invention. The reaction container 11 accommodates a sample table 13 on which a sample (substrate to be processed) 10 is placed, and an electrode 14 arranged to face the sample table 13. A heater 15 for heating the sample 10 is embedded inside the sample table 13, and the heater 15 heats the sample 10 to, for example, 500 ° C. Electrode 14
Is applied with a high frequency of 13.56 MHz, and plasma is generated in the reaction vessel 11 by the high frequency application. Further, 16 is a gas inlet, and 17 is a gas exhaust port, and the inside of the reaction vessel 11 is evacuated to a level of 10 ⁻⁸ Torr.

Next, a process of forming a multilayer wiring using the apparatus of FIG. 1 will be described with reference to FIGS.
First, as shown in FIG. 2A, a thermal oxide film 21 having a thickness of 10 nm and a first layer Al having a thickness of 800 nm are formed on a Si substrate 20.
After forming the alloy thin film 22 and patterning the Al alloy thin film 22, a 800-nm-thick CVD oxide film 23 is deposited and a via hole 24 is formed by reactive ion etching. The sample 10 was placed on the sample table 13 of the surface treatment apparatus shown in FIG. 1, and the inside of the container 11 was evacuated.
At this time, the first layer Al alloy thin film 22 of the via hole 24
A natural oxide film 25 was formed on the surface of the.

Then, 50 sccm of BCl ₃ gas was introduced from the gas inlet 16, the inside of the reaction vessel 11 was kept at 0.1 Torr, and a high frequency of 13.56 MHz was applied to the electrode 14,
A plasma of BCl ₃ gas was generated. By the treatment for about 1 minute, the natural oxide film (Al ₂ O ₃ ) 25 becomes Al ₂ Cl.
₆ and (BClO) ₃ . However, as a result, as shown in FIG. 2B, the halide layer 26 containing B and Cl was formed on the surface of the first-layer Al alloy thin film 22 in the via hole 24.

Next, 50 sccm of B ₂ H ₆ gas was introduced through the gas inlet 16, the sample 10 was heated to 100 ° C. and held for 10 minutes. B ₂ H ₆ decomposed on the sample surface, as shown in Fig. 2 (c).
As shown in, Cl of the halide layer 26 is HCl or BC.
It was removed as l ₃ .

Then, the WF ₆ gas 1 is introduced from the gas inlet 16.
0 sccm and SiH ₄ gas of 30 sccm were introduced, and sample 10 was added to 2
Hold at 00 ° C. By this treatment, the W thin film 27 was deposited selectively and with good uniformity only on the surface of the first layer Al alloy thin film 22 of the via hole 24. By the treatment for about 5 minutes, the via hole 24 was completely filled with the W thin film 27 as shown in FIG.

Then, as shown in FIG. 2 (e), an Al alloy thin film 28 was deposited and patterned to form a second layer wiring. The wiring resistance of the multilayer wiring thus formed was sufficiently low.

On the other hand, when the W thin film is formed without removing the halide layer 26 containing B or Cl, a nonuniform W thin film 29 is formed as shown in FIG.
W not only on the alloy thin film 22 but also on the CVD oxide film 23
Thin film 29 was deposited. The wiring resistance was also about one digit higher than that of the one subjected to the B ₂ H ₆ treatment.

As described above, according to the method of this embodiment, the halide layer 26 remaining after the natural oxide film 15 is removed.
Is removed by introducing B ₂ H ₆ gas, selective CVD with high selectivity can be performed, the via hole 24 can be completely filled with the W thin film 27, and a multilayer wiring with low wiring resistance can be formed. . (Second embodiment)

This embodiment relates to the embedding of W in the contact hole, and is approximately the same as the first embodiment. That is, W is deposited not on the first layer Al alloy wiring but on the impurity diffusion layer of Si, but the native oxide film on the Si surface is removed by including F element such as F ₂ plasma or F ₂ gas downflow etching. Gas is used. As a result S
Although F remains on the i surface, this F can be removed by exposing it to SiH ₄ gas while keeping the Si substrate at about 300 ° C., for example. This is because SiH ₄ decomposes on the Si surface, and the generated H or Si removes F as HF or SiF ₄ .

Also in this case, similarly to the first embodiment described above, a uniform W thin film can be deposited in the contact hole with high selectivity, and a contact with low contact resistance can be formed. .

In the SiH ₄ gas treatment in the above embodiment, for example, the work function of Si (about 4.8e) like that of an ArF laser (193 nm) is maintained while the substrate temperature is kept at room temperature.
V) may be changed to a process of irradiating with light having higher energy and less absorption by SiH ₄ gas. In this case, photoelectrons are emitted from Si in the contact hole, and the electrons decompose SiH ₄ gas, and the produced Si and H remove F on the Si surface. Using this method, Si
The F on the surface is removed faster than the F on the oxide film, and the selectivity during W deposition is further improved. (Third embodiment)

FIG. 3 is a sectional view showing a schematic structure of a surface treatment apparatus used in the third to fifth embodiment methods. This equipment is equipped with a processing chamber 31 for removing a natural oxide film and halogen.
And a process chamber 32 for performing processes such as oxidation, impurity diffusion, and single crystal growth. The sample 30 does not have its surface exposed to the atmosphere via the gate valve 33 and the process chamber 31 and the process chamber. It is transported between 32. In the processing chamber 31, the sample 30 is placed on a sample table 35 in which a heater 34 is embedded, and heated to about 500 ° C. on the sample table 35.

An electron beam source 36 can irradiate the entire surface of the sample 30 with an electron beam. In addition, the gas inlet 37
The gas introduced from a is exhausted from the gas exhaust port 37b. The process chamber 32 includes a gas inlet 38a, a gas outlet 38b, and a heater 39 capable of heating the sample up to 1000 ° C. By introducing oxygen, an impurity gas, a deposition gas, etc. from the gas inlet 38a, the process chamber 32 is oxidized. Processes such as impurity diffusion and single crystal growth can be performed. Next, a process of forming a thermal oxide film of silicon using the apparatus of FIG. 3 will be described with reference to FIGS.

First, a mixed solution of sulfuric acid / hydrogen peroxide water and hydrochloric acid /
A silicon substrate from which surface metal contamination and organic substances have been removed by using a hydrogen peroxide solution mixture is used as a sample table 35 of the apparatus shown in FIG.
And the inside of the processing chamber 31 is evacuated. At this time, as shown in FIG. 4A, the natural oxide film 41 was formed on the surface of the silicon substrate 40.

Then, HF gas was introduced from the gas inlet 37a to keep the inside of the processing chamber 31 at 100 Torr. By this treatment, the natural oxide film (SiO ₂ ) 41 is changed to SiF ₄ or HF.
Was removed as. The Si surface after the treatment was covered with H and F as shown in FIG. That is, the residual layer 42 of halogen was formed.

Then, the inside of the processing chamber 31 was evacuated to a level of 10 ^-8 Torr, and then, while keeping the sample 30 at about 300 ° C., an electron beam of 500 eV was irradiated for about 20 minutes. As a result, as shown in FIG. 4C, the layer 42 contaminated with F was removed, and a surface partially covered with H was obtained. This is because F on the Si surface is F ₂ , SiF ₄ ,
This is because it was removed as HF and part of H was also released as H ₂ and SiH ₄ .

Then, Ar gas is introduced from the gas inlet 37a to return the inside of the processing chamber 31 to the atmospheric pressure, and then the sample 30 is placed in the process chamber 32 whose inside is replaced with Ar gas through the gate valve 33. To transport. At this time, sample 30
Surfaces are not exposed to the atmosphere.

Then, while the sample 30 is heated to about 900 ° C., oxygen gas is introduced from the gas inlet 38a, as shown in FIG.
As shown in (d), a thermal oxide film 43 of about 5 nm was formed. When the dielectric breakdown voltage of the thermal oxide film 43 thus formed was measured, 95% showed a dielectric breakdown breakdown voltage of 8 kV / cm or more. As described above, according to this example, a high-quality thermal oxide film having a high breakdown voltage could be formed.

On the other hand, the thermal oxide film formed by thermal oxidation without the above-mentioned F removal treatment is only 80% and 8 k.
It did not show a withstand voltage of V / cm or higher. This is shown in Figure 4.
This is because the F contamination layer 44 is formed between the thermal oxide film 43 and the Si substrate 40, as shown in (e). (Fourth Embodiment) As a fourth embodiment of the present invention, a method for growing a silicon single crystal on a silicon substrate will be described.

First, as in the third embodiment, the metal contamination and organic substances on the surface of the silicon substrate are removed by using a sulfuric acid / hydrogen peroxide mixture solution or a hydrochloric acid / hydrogen peroxide mixture solution, and the processing chamber 31 is used. The natural oxide film is removed by HF gas inside. Then, H ₂ gas was introduced from the gas inlet 37a, and the sample 30 was heated to about 400 ° C. while maintaining the inside of the processing chamber at 10 ⁻⁷ Torr.
And heat the sample surface to 100 eV of electron beam
Irradiate for 5 minutes. By this treatment, the F remaining on the Si surface due to the treatment using the HF gas is converted into HF, F ₂ , SiF.
_It became ₄ and was removed.

Next, this sample was conveyed to the vacuum-exhausted process chamber 32 without exposing the surface to the atmosphere, and SiH ₂ Cl ₂ gas was introduced from the gas inlet 38a and the sample was heated to about 1000 ° C. , Si was epitaxially grown. The single crystal Si thus formed had a uniform film thickness and had almost no defects. On the other hand, the epitaxially grown one without removing F is
Si grew unevenly and had many defects. As described above, according to this example, it was possible to grow high-quality single crystal Si. (Fifth Embodiment) An impurity diffusion step will be described as a fifth embodiment of the present invention.

First, after removing metal contamination, organic contamination, etc. on the surface of the silicon substrate by wet cleaning, this sample 3
0 on the sample table 35 of the processing chamber 31 shown in FIG.
The inside of the processing chamber is evacuated.

Next, solid NH ₄ F is heated, and the generated gas is introduced from the gas introduction port 37a, whereby NH ₄ F is formed again on the surface of the sample. This NH ₄ F is a natural oxide film S
Reacts with iO ₂ to form (NH ₄ ) ₂ SiF ₆ and H ₂ O. H ₂ O is immediately exhausted as a gas, but (NH
₄ ) ₂ SiF _{6 is} also decomposed into NH ₃ , HF, and SiF ₄ by heating the sample to 100 ° C. or higher and removed. The Si surface from which the natural oxide film has been removed by such treatment is covered with F and H.

Then, crystals of oxalic acid ((COO
H) ₂ ) is heated to 120 ° C. for sublimation, and the generated gas is introduced into the processing chamber 31 through the gas introduction port 37a.
Was kept at 300 ° C. for 10 minutes. By this treatment, F on the Si surface was removed. This is because oxalic acid decomposes on the sample surface to produce CO, CO ₂ , HCOOH, etc.
Of these, CO and HCOOH react with F, COF, C
It is considered that OF ₂ and HF were generated and F was removed.

Next, after the sample 30 was conveyed to the process chamber 32 without being exposed to the atmosphere, AsH ₃ was introduced from the gas inlet 38a while keeping the sample 30 at about 500 ° C.
Was diffused inside Si. As a result, a uniform diffusion layer could be formed. On the other hand, in the sample in which As was diffused without removing F, As was diffused nonuniformly, and the diffused As was small. This is because F remaining on the Si surface hindered diffusion. As described above, according to the present embodiment, it is possible to perform efficient and uniform impurity diffusion. (Sixth Embodiment) As a sixth embodiment of the present invention, anisotropic dry etching processing of an Al alloy thin film and resist removal will be described.

FIG. 5 is a sectional view showing a schematic structure of the surface treatment apparatus used in this embodiment. The sample 50 is the reaction container 5
It is placed on the sample table 52 housed in 1. Although not shown, the sample table 52 has a rotation function, and the sample 50 is horizontally rotated about its center. Gas is introduced into the reaction vessel 51 from the gas introduction port 53a through the discharge tube 54 and exhausted from the gas introduction port 53c. Further, the gas is introduced into the reaction vessel 51 through the gas introduction port 53b.
It is also possible to introduce the gas directly from.

A cavity 57 connected to a waveguide 55 is installed in the discharge tube 54, and a microwave of 245 GHz generated by a microwave power source 56 is transmitted to the cavity 57. Then, a microwave discharge is generated inside the discharge tube 54.

An electrode 58 is provided inside the reaction vessel 51 so as to face the sample table 52.
A high frequency discharge is generated by applying a high frequency of 3.56 MHz. Further, a quartz window 59 is installed on the upper wall portion of the reaction vessel 51, and the sample 50 is passed through this window 59.
It is possible to irradiate light on. Next, anisotropic dry etching processing and resist removal of the Al alloy thin film will be described with reference to process sectional views of FIGS.

First, as shown in FIG. 6A, a 100 nm oxide film 61 is formed on a Si substrate 60 by thermal oxidation, and a 500 nm Al-Si-Cu alloy thin film 62 is deposited by sputtering. Further, after applying the resist 63, the resist 63 is patterned by photolithography.

Next, this sample 50 is placed on the sample table 52 of the apparatus shown in FIG. 5, the inside of the reaction vessel 51 is evacuated, and then 30 sccm of BCl ₃ gas is introduced from the gas introduction port 53a, Keep the inside of 51 at 0.03 Torr. Furthermore, a high frequency of 13.56 MHz is applied to the electrode 58,
A plasma of BCl ₃ gas is generated to generate an Al alloy thin film 62.
The native oxide film on the surface is removed.

Then, instead of BCl ₃ , Cl ₂ gas 50 was added.
A sccm is introduced, a high frequency is applied to the electrode 58 while keeping the inside of the reaction vessel 51 at 0.01 Torr, and Cl ₂ plasma is generated. By processing for 10 minutes, the Al alloy thin film 62 was vertically etched as shown in FIG.
At this time, a contamination layer 64 containing Cl was formed on the side wall of the Al alloy thin film 62.

Next, CF ₄ gas 50 sccm and O ₂ gas 5
00 sccm is introduced through the gas introduction port 53a, and the reaction container 51
The gas was discharged inside the discharge tube 54 while keeping the inside of 0.2 Torr. As a result of processing for about 15 minutes,
The resist 63 was removed as shown in FIG. By this treatment, a layer 65 containing F is formed on the upper surface of the Al alloy thin film 62.
Was formed, and a layer 66 containing Cl and F was formed on the sidewall.

Next, 100 sccm of NH ₃ gas was introduced from the gas inlet 53a, and the ArF laser beam (wavelength 1) was passed through the quartz window 59 while keeping the inside of the reaction vessel 51 at 1 Torr.
(93 nm) was irradiated to the sample 50, and the sample 50 was rotated at the same time. NH ₃ is decomposed by ArF laser light to generate H radicals. The H radicals react with F and Cl of the contaminated layers 65 and 66 and remove them as HF and HCl, so that the contaminated layers 65 and 66 can be removed as shown in FIG. 6D.

The thus-processed F and Cl removal treatment did not cause any corrosion even when exposed to the atmosphere. On the other hand, in the case where the above treatment was not performed, 95% caused corrosion and the Al alloy thin film was broken. As described above, according to this example, the halogen on the surface of the Al alloy thin film was removed, and the corrosion could be suppressed.

Although the treatment using halogen and the treatment for removing halogen are carried out in the same container in this embodiment, they may be carried out in different containers. However, when transporting the sample, if the surface is directly exposed to the atmosphere without controlling the atmosphere, corrosion occurs, so the transport should be performed in an inert gas such as nitrogen gas or in a vacuum, or as in this example. It is desirable to continuously perform the treatment in the same container without exposing the surface to the atmosphere.

In the above embodiment, the CF ₄ and O ₂ mixed gas is discharged and the active species generated are used to remove the resist, but it is also possible to remove the resist using another halogen-containing gas. For example, when 50 sccm of NF ₃ gas was introduced from the gas introduction port 53a and discharged by the discharge tube 54, and 100 sccm of H ₂ O gas was introduced from the gas introduction port 53b, the resist was removed by the treatment for about 5 minutes. Also at this time A
Although F remained on the surface of the 1-alloy thin film 62, it was completely removed by the method described in the above embodiment, and no corrosion occurred even if the sample was exposed to the atmosphere after the treatment. (Seventh Embodiment) As a seventh embodiment of the present invention, embedding of W into a contact hole will be described with reference to the process sectional views of FIGS.

First, as shown in FIG. 7A, after forming an interlayer insulating film 71 on a silicon substrate 70, a contact hole 72 is opened by reactive ion etching, and the substrate surface exposed in the contact hole 72. Then, the impurity diffusion layer 73 is formed.

Next, as shown in FIG. 7B, a Ti film 74 of 100 nm is formed by sputtering. continue,
As shown in FIG. 7C, annealing is performed at 700 ° C. for 20 minutes to silicify Ti at the bottom of the contact hole to form Ti.
A Si ₂ film 75 is formed, and the sample is immersed in a sulfuric acid / hydrogen peroxide solution to remove unreacted Ti. At this time, Ti
The natural oxide film 76 was formed on the surface of the Si ₂ film 75.

Next, this sample 10 is placed on the sample table 13 in the reaction container 11 shown in FIG. 1, and the inside of the container is evacuated. Then, F ₂ diluted with He was introduced from the gas inlet 16
Was introduced, and a high frequency was applied to the electrode 14 while maintaining the inside of the reaction vessel 11 at 0.1 Torr to generate plasma of F ₂ / He gas. By maintaining this state for about 2 minutes, the native oxide film 76 on the TiSi ₂ surface could be removed. However, as shown in FIG. 7D, TiF _x or Si was used instead.
It was covered with a layer 78 containing F, such as F _x .

Then, the F ₂ / He gas is introduced into the gas exhaust port 17
After evacuating from the above, CO gas was introduced from the gas inlet 16 and the sample 10 was heated to 350 ° C. and kept for 10 minutes while keeping the inside of the reaction vessel 11 at 0.6 Torr. By this treatment, as shown in FIG. 7E, the F-containing layer 78 on the surface of the TiSi ₂ film was removed. This is F for CO
It is thought that it was extracted as F or COF ₂ .

Then, instead of CO, WF ₆ / SiH ₄
The mixed gas is introduced into the reaction vessel through the gas inlet port 16,
Sample 10 was heated to 250 ° C. and held for 5 minutes. As a result, as shown in FIG. 7F, the contact hole 72 was filled with the W film 79. At this time, W is the TiSi film 75
, But it did not grow at all on the insulating film 71. Moreover, the contact resistance was sufficiently low. On the other hand, if the treatment using CO is not performed, W
Causes abnormal growth, grows on the insulating film 71, and has high contact resistance.

As described above, according to this embodiment, F ₂ / He
TiS by natural oxide film removal process using gas plasma
F formed on the i ₂ surface could be removed by introducing CO gas, and the selectivity of W selective CVD could be improved and the contact resistance could be reduced. (Eighth Embodiment) As an eighth embodiment of the present invention, formation of multilayer wiring will be described with reference to FIG.
This embodiment is roughly the same as the first embodiment.

First, as shown in FIG. 2A, a 100 nm thermal oxide film 21 and a 800 nm first layer Al alloy film 22 are formed on a Si substrate 20, and the Al alloy film is patterned. The oxide film 23 is deposited and CHF ₃ / H ₂
The via hole 24 is opened by reactive ion etching using a mixed gas.

This sample 10 is a reaction container 11 shown in FIG.
The sample is placed on the sample table 13 and the inside of the container 11 is evacuated. At this time, although a layer containing F was formed on the surface of the first layer Al alloy film 22, CO gas was introduced from the gas inlet 16 and the sample 10 was heated to 300 ° C. and held for 10 minutes. As a result, this F is removed as COF or COF _{2, and} as shown in FIG.
Only _{20 3} ) 25 was formed on the surface of the Al alloy film.

Next, 50 sccm of BCl ₃ gas was introduced from the gas inlet 16, and high frequency was applied to the electrode 14 while maintaining the inside of the reaction vessel 11 at 0.3 Torr to generate BCl ₃ gas plasma. By performing the treatment for about 2 minutes, the natural oxide film (A1 ₂ 0 ₃ ) 25 becomes Al ₂ Cl ₆ or (B
It was removed as ClO) ₃ . But instead,
As shown in (b), a layer 26 containing Cl was formed on the surface.

Then, CO gas was introduced through the gas inlet 16 and the sample 10 was heated to 300 ° C. and held for 10 minutes. As a result of this treatment, as shown in FIG.
Cl of 6 was removed as COCl and COCl ₂ .

Next, from the gas inlet 16 to WF ₆ / Si
The H ₄ mixed gas was introduced, and the sample 10 was heated to 200 ° C. By this treatment, the W film was selectively deposited only on the Al alloy film 22 and was not deposited on the CVD oxide film 23 at all. By the treatment for about 5 minutes, the W film 27 was completely embedded in the via hole 24 as shown in FIG. Further, as shown in FIG. 2E, an Al alloy film was formed and patterned to form a second-layer Al wiring 28.

The wiring resistance of the multilayer wiring thus formed was sufficiently low. In contrast, W without removing Cl
2F, a non-uniform W film 29 grows, and the W film 29 is also formed on the CVD oxide film 23, as shown in FIG.
Grew up. In addition, the residual Cl at the W / Al interface caused corrosion of the Al alloy.

As described above, according to this embodiment, the selective CVD of W having a high selectivity can be performed, the via hole 24 is completely filled, the wiring resistance is low, the corrosion does not occur, and the multilayer wiring is highly reliable. Could be formed. (Ninth Example)

As a ninth embodiment of the present invention, dry etching processing and resist removal of an Al alloy thin film will be described with reference to FIG. This embodiment is approximately the same as the sixth embodiment.

First, as shown in FIG. 6A, a 100 nm oxide film 61 is formed on a Si substrate 60 by thermal oxidation, and an Al-S film having a thickness of 800 nm is sputtered on the oxide film 61.
The i-Cu alloy film 62 is deposited. Further, a resist 63 is applied on this, and the resist 63 is patterned by photolithography.

Next, this sample was placed in the reaction vessel 51 shown in FIG. 5, and after being evacuated, BCl ₃ gas of 10 sccm and Cl ₂ gas of 30 sccm were introduced from the gas introduction port 53a to remove the inside of the reaction vessel 51. While keeping at 0.06 Torr,
Applying a high frequency of 13.56 MHz to the electrode 58 and applying BCl
A plasma of ₃ / Cl ₂ mixed gas is generated. By the treatment for 10 minutes, as shown in FIG. 6B, the Al alloy film 6
2 was etched vertically. At this time, the Al alloy film 6
A contamination layer 64 containing Cl was formed on the sidewall of No. 2.

Next, CF ₄ gas 30 sccm and O ₂ gas 3
00 sccm is introduced through the gas introduction port 53a, and the reaction container 51
CF inside the discharge tube 54 while keeping the inside of 0.3 Torr
_{The 4} / O ₂ mixed gas was discharged. By the treatment for about 20 minutes, the resist 63 was removed as shown in FIG. On the upper surface of the Al alloy film 62 that has undergone such treatment, F
And a layer 66 containing Cl and F was formed on the side wall.

Then, instead of the CF ₄ / O ₂ mixed gas, CO gas is introduced through the gas introduction port 53a, and the sample 50
Was kept at about 300 ° C. for 10 minutes. By this treatment, as shown in FIG. 6D, F and Cl on the surface of the Al alloy film 62 were removed as COF _x and COCl _x .

The sample from which F and Cl were removed from the surface of the Al alloy as described above did not cause any corrosion even when exposed to the atmosphere.
On the other hand, about 90
% Of wiring was corroded and disconnected. As described above, according to the present embodiment, the halogen on the surface of the Al alloy can be removed, the corrosion can be suppressed, and the reliability of the wiring can be improved. (Tenth Example)

In this embodiment, halogen removal is applied to the surface of a vacuum component. That is, when etching or CVD using a gas containing halogen is performed in the reaction vessel 11 as shown in FIG. 1, halogen remains on the wall surface of the reaction vessel 11 and the water content remaining in the vessel 11 Reacts with acid to corrode the container wall.

After the present invention is applied and a treatment using a halogen gas is performed, the wall surface of the container is reduced to about 1 while flowing CO gas.
By heating to 50 ° C., the halogen was removed and no corrosion occurred. (Eleventh Embodiment) This embodiment is a modification of the seventh embodiment and is different from the seventh embodiment in the method of removing the natural oxide film on the TiSi ₂ surface.

That is, the native oxide film 76 on the surface of the TiSi ₂ film 75 is removed by using the device shown in FIG. 5 instead of the device shown in FIG. Specifically, 30 sccm of SF ₆ gas and ₆₀ sccm of H ₂ O gas are introduced from the gas introduction port 53a,
While maintaining the inside of the reaction vessel 51 at 5 Torr, a microwave (300 W) of 2,45 GHz is applied to the cavity 57 to discharge the SF ₆ / H ₂ O mixed gas and hold it for 10 minutes. As a result, H is formed on the surface of the TiSi ₂ film 75.
A liquid containing F, H ₂ SO ₄ , HSO ₃ F, etc. is formed to remove the natural oxide film 76.

When the natural oxide film 76 is removed by such a treatment, TiF _x and Si are formed on the surface of the TiSi ₂ film 75.
In addition to F _x , sulfur such as S, SO _x , SO _x F _y , and SF _x and sulfur compound 78 remain. Similar to the seventh example, when the sample was heated to 350 ° C. while flowing CO gas and held for 10 minutes, sulfur and sulfur compounds were removed in addition to fluorides such as TiF _x and SiF _x . . It is considered that this is because CO extracted S and was removed as OCS gas.

TiSi ₂ film 75 which has been subjected to such a treatment
A good W film 79 with good uniformity is formed on the
Similar to the example, the selective CVD selectivity was improved and the contact resistance was reduced. (Twelfth Embodiment) The present embodiment is a modification of the sixth embodiment, in that CO is used instead of NH ₃ as a means for removing residual halogen after resist removal.

That is, from the state shown in FIG. 6B, the resist 63 is removed by using CF ₄ / O ₂ or NF ₃ / H ₂ O gas, and then ArF laser light is applied while flowing NH ₃ gas. In addition, the gas inlet 53a is provided in the reaction vessel 51.
CO gas is introduced from above, and the sample 50 is heated to 350 ° C., 1
Hold for 0 minutes. Even by such a treatment, the F remaining on the Al alloy thin film 62 was completely removed, and even when the sample 50 was exposed to the atmosphere, no corrosion occurred.

The present invention is not limited to the above embodiments. In the embodiment, borane gas, SiH ₄ , and NH ₃ are used as the compound gas containing hydrogen element in the molecule, but carborane gas (B _x C ₂ H _{x + 2} ) and B are used.
_x H _{x + 4} , B _x H _{x + 6} , C _x H _2x-2 , C _x H _2x , C _x H
_{2x + 2} , N ₂ H ₄ , Si _x H _{2x + 2} , PH ₃ , AsH ₃ , G
e _x H _{2x + 2} , H ₂ S, HCN, CsH, HI, and N
A gas such as HR ₁ R ₂ (R ₁ , R ₂ = C _x H _y ) may be decomposed on the sample surface. Also, if a gas containing such a hydrogen element is decomposed using a discharge or light at a place apart from the sample, hydrogen atoms are generated, but even if this hydrogen atom is supplied to the sample, the halogen on the sample surface is removed. can do. These compound gases have a very high hydrogen element generation efficiency and can dramatically improve the halogen removal efficiency.

Further, in the embodiment, halogen is removed by using CO gas, but N _x such as NO, N ₂ O, NO _{2 and the} like is used.
If O _y gas is used, F is removed as NOF _x or the like. Furthermore, other than (COOH) ₂ , carboxylic acids such as HCOOH and CH ₃ COOH, HCHO and CH ₃ C
Even if an aldehyde such as HO, a carbonyl compound, C ₃ O ₂ or the like is used, CO is generated by the decomposition, so that the halogen can be removed. Further, in the present invention, hydrogen element, C
A gas containing a compound molecule containing at least one of O and NO may be used, or a mixed gas of the above gases may be used. Furthermore, the surface for removing the halogen is not limited to the metal or the semiconductor forming the semiconductor element, and the wall surface of the reaction container for internally performing the treatment using the halogen gas described in the tenth embodiment. For example, it may be used on a metal surface where corrosion is a problem, such as a surface of a reaction container, a vacuum component, or a gas pipe exposed to a halogen gas.
Besides, various modifications can be applied without departing from the scope of the present invention. Next, another embodiment of the present invention will be described.

In the subsequent examples, a sample having a semiconductor (or metal) on which a natural oxide film was formed was housed in a reaction vessel, and the semiconductor surface in the vessel was selected from gas, liquid and solid containing hydrogen halide. After making contact with the ground, the potential of the semiconductor is kept negative with respect to the ground potential, the potential of the electrode installed facing the semiconductor, or the potential of the container wall, while the gas, liquid, or solid containing hydrogen halide is used as the semiconductor. It is characterized in that it is removed from. (Thirteenth Example)

FIG. 8 is a sectional view showing the schematic arrangement of a surface treatment apparatus according to the 13th embodiment. This device is used for sample 8
A container 81 holding a liquid 82 containing hydrogen halide, in which 0 is dipped, an electrode 85 provided on the opposite side of the surface of the sample 80 on which a semiconductor element is formed, and an electrode 85 provided opposite to the sample 80. The counter electrode 86 is included. Here, a bias is applied to the electrode 85 so that the potential becomes negative with respect to the counter electrode 86. The electrodes 85 and 86 may be installed in the liquid 82 as shown in FIG. 8 or may be installed outside the container 81. Further, although not shown, a means for pulling up the sample 80 from the liquid 82 is provided while maintaining the positional relationship between the sample 80, the electrode 85, and the counter electrode 86 and the bias direction. (Fourteenth Example)

FIG. 9 is a sectional view showing the schematic arrangement of a surface treatment apparatus according to the 14th embodiment. This device is similar to the device shown in FIG. 1 and includes a vacuum container 91, a sample stage 93,
Heater 95, gas inlets 96a and 96b, gas outlet 9
7 and a counter electrode 98. A bias is applied to the sample table 93 so that the potential is negative with respect to the counter electrode 98.

This apparatus can remove the natural oxide film on the sample surface by introducing a gas containing hydrogen halide from the gas inlets 96a and 96b, and by introducing a CVD gas, A metal such as Si or a semiconductor can be formed on the sample surface. As described above, this apparatus serves as an apparatus for removing the natural oxide film on the sample surface, or as a CVD apparatus, and after removing the natural oxide film on the sample surface, forms a film on the surface without exposing the surface to the atmosphere. It can be used as a CVD apparatus. (Fifteenth Example)

Next, an example in which W is embedded in the contact hole using the surface treatment apparatus shown in FIG. 8 will be described. In this example, the apparatus shown in FIG. 9 is used as a W CVD apparatus. FIG. 10 is a sectional view of the process.

First, as shown in FIG. 10A, after forming an insulating film 101 having a thickness of 1 μm on a silicon substrate 100, the diameter of the insulating film 101 was reduced by reactive ion etching using a mixed gas of CF ₄ and H _2. 1 μm contact hole 102
And a diffusion layer 103 is formed by ion implantation of As. Then, using a mixed solution of H ₂ SO ₄ and H ₂ O ₂ , organic contaminants on the surface of the diffusion layer 103 were removed. By this treatment, the natural oxide film 104 was formed on the surface of the diffusion layer 103.

This sample was placed in a container 81 shown in FIG.
% HF aqueous solution 82 and kept for about 2 minutes. Next, the electrode 85 is -0.5 V, and the counter electrode 86 is +0.5 V.
A bias of V was applied. The sample 80 was pulled up from the HF aqueous solution to the atmosphere while maintaining the positional relationship between the sample and the electrode and the counter electrode and the bias state, and the HF aqueous solution slightly adhering to the sample surface was removed by spraying dry nitrogen gas. After that, the bias of the electrode 85 and the counter electrode 86 is cut off,
The sample 80 was separated from the electrode 85. After doing this process,
When the surface of the diffusion layer 103 was analyzed, only a small amount of physically adsorbed oxygen was detected in addition to hydrogen and silicon. No fluorine was detected on this surface.

As described above, the surface of the diffusion layer 103 is formed as shown in FIG.
As shown in FIG. 0 (b), the surface 105 was covered with almost only hydrogen without a natural oxide film or fluorine. This is when raising the sample from the aqueous HF solution, because it was kept potential of the sample surface in the negative, F on the sample surface ^- , Ions and OH ^- This is because the ions cannot come close to each other, and the H ⁺ ion, which is the only ion having a positive charge, approaches the silicon surface and is adsorbed in the liquid.

Next, the sample is placed on the sample table 93 in the vacuum container 91 shown in FIG. 9, the interior of the container 91 is evacuated, and then the temperature of the sample 90 is raised to 300 ° C., and the gas inlet 96a.
30 sccm of WF ₆ gas and 50 sccm of SiH ₄ gas were introduced from the above and held for 1 minute. As a result, as shown in FIG. 10C, the contact hole 102 was completely filled with the W film 106. The deposited shape of the W film 106 was very good, and the W film 106 was not deposited on the insulating film 101 at all. The contact resistance was also the same as when the contact hole 102 was filled with Al alloy by sputtering. On the other hand, the sample drawn out from the HF aqueous solution 82 without applying a bias and having W deposited thereon, as shown in FIG. 10 (d), even if WF ₆ and SiH ₄ gas was flowed for 5 minutes. In addition, it was not possible to completely fill the contact hole 102. Furthermore, the accumulated W
Since the film 106 had an abnormal shape and the gas was allowed to flow for a long time, the W film 107 was also deposited on the insulating film 101. Further, the contact resistance was about one digit higher than that shown in FIG.

As described above, the surface before deposition of W is covered with only hydrogen by using the surface treatment apparatus shown in FIGS. 8 and 9, so that the W film is well deposited and contacted. It was possible to form a W / Si interface with low resistance. The hydrogen covering the Si surface hardly hinders the deposition of W. However, this is because the electronegativity of hydrogen is relatively small and the S of WF ₆ gas is relatively small.
It is considered that the dissociation on the i surface is not hindered or the F of the WF ₆ gas removes hydrogen as HF. (Sixteenth Embodiment) FIG. 11 is a sectional view showing a schematic structure of a surface treatment apparatus.

This device is similar to the device shown in FIG. 5, and includes a vacuum container 111, a sample table 112, a gas inlet 113a, a gas outlet 113c, a discharge tube 114, a waveguide 115, and a microwave power source. 116, a cavity 117, an electrode 118, a heater 119 and the like.

The heater 119 is embedded inside the sample table 112 and can heat the sample 110 to 200 ° C. Further, a bias is applied to the sample table 112 so that the potential becomes negative with respect to the counter electrode 118 that is installed to face it. The gas introduced from the gas introduction port 113a is discharged in the discharge tube 114. Of the active species generated by the discharge, only those having a long life are transported into the container 111 and supplied to the surface of the sample 110. (17th Example)

Next, a surface treatment method using the surface treatment apparatus shown in FIG. 11 will be described. In the present embodiment, the natural oxide film on the silicon surface is replaced by the one shown in FIG.
It is the same as the fifteenth embodiment except that it is removed using the apparatus shown in FIG. That is, first, the sample shown in FIG. 10A is placed on the sample table 112, and the inside of the vacuum container 111 is evacuated. Then, with the sample 110 kept at room temperature, a mixed gas of 5 sccm of NF ₃ gas and 30 sccm of NH ₃ gas was introduced into the discharge tube 114 through the gas introduction port 113a.
A microwave of 45 GHz was applied and discharged to hold for 5 minutes. By this treatment, the natural oxide film 104 on the surface of the diffusion layer 103 was changed to a film containing (NH ₄ ) ₂ SiF ₆ and NH ₄ F. The generation of NH ₄ F can be explained as F radicals generated by discharging NF ₃ abstract H from NH ₃ to form HF, and HF and NH ₃ are bound to each other. On the other hand, (NH ₄ ) ₂ SiF ₆ is a product formed by the reaction of NH ₄ F and SiO ₂ .

Next, a bias of −0.5 V is applied to the sample table 112 and a bias of +0.5 V is applied to the counter electrode 118, the sample 110 is heated to 150 ° C. while flowing the mixed gas, and held for 30 seconds to form a film. After sublimation and removal, the temperature is returned to room temperature, the introduction of the mixed gas is stopped, and the vacuum container 111
The inside of was evacuated. By such processing, the first
As in the embodiment of FIG.
It can be covered with only hydrogen as shown in (b), and by depositing W on this surface, a good W deposit and a W / Si interface with low contact resistance are formed. We were able to.

In this embodiment, NH ₄ F is used for forming NH ₄ F.
Discharge of mixed gas of ₃ and NF ₃ was used, but NH ₃ or NF
Either one of ₃ is discharged and mixed in the vacuum container, or the NH ₄ F powder is heated, and the generated gas is mixed with the vacuum container 41.
Or to introduce NH ₃ gas and HF gas into the vacuum container 41.
You may introduce in. (Eighteenth Example)

In this embodiment, Si at the bottom of the contact hole in the seventeenth embodiment is replaced with Al alloy at the bottom of the via hole, and NH ₄ F is replaced with NH ₄ Cl. Also in this case, the natural oxide film on the Al alloy surface is removed by using NH ₄ Cl, and then the NH ₄ Cl is removed while applying a bias to form an Al alloy surface covered with hydrogen. It is possible to form a W / Al interface having a low via resistance by satisfactorily depositing W. Further, since chlorine does not remain at the W / Al interface formed in this way, corrosion does not occur even when water reaches the W / Al interface through the W film. (Nineteenth Embodiment) As a nineteenth embodiment, epitaxial growth of Si will be described. As the device, the one shown in FIG. 9 is used.

First, the H ₂ SO ₄ / H ₂ O ₂ mixture liquid and HC
Using a 1 / H ₂ O ₂ mixed solution, organic contaminants and heavy metal contaminants on the Si substrate surface are removed. Next, this sample is placed on the sample table 93 of the apparatus shown in FIG. 9, the inside of the vacuum container 91 is evacuated, and then the HF gas 2 is supplied from the gas inlet 96b.
0 Torr and H ₂ O gas of 20 Torr were introduced and held for 5 minutes. Next, while the gas is flowing, −0.
5V, + 0.5V bias is applied to the counter electrode 98,
After holding for 30 seconds, the supply of the gas is stopped, and the inside of the vacuum container 91 is evacuated to an ultrahigh vacuum of 10 ^-8 Torr or more,
The bias was then turned off. By this treatment, the natural oxide film on the surface of the silicon substrate was removed and the surface was covered only with hydrogen.

Next, this sample was heated to 1000.degree. Hydrogen on the silicon surface was removed during this temperature rising process.
Next, from the gas inlet 96a, SiH ₂ Cl ₂ gas 50sc
cm, H ₂ gas of 100 sccm was introduced and held for 10 minutes.
By this treatment, silicon having a thickness of about 1 μm was epitaxially grown. The epitaxial silicon thus formed did not contain any defects, and impurities such as fluorine and oxygen were not detected from the interface with the silicon substrate.

On the other hand, even if the device shown in FIG. 9 is used for the growth, when the natural oxide film is removed and HF and H ₂ O gas are introduced without applying a bias, many defects are generated. Only the contained silicon grew. Fluorine was detected from the interface between the epi-silicon and the silicon substrate, and it is considered that this fluorine caused defects. As described above, by using the method of this example, a good-quality epitaxial silicon film could be grown. (Twentieth Embodiment) As a twentieth embodiment, a thermal oxidation apparatus for Si will be described. FIG. 12 is a schematic diagram thereof.

This apparatus comprises a pretreatment chamber 510 and a thermal oxidation chamber 52.
0, and both are separated by a gate valve 530. The pretreatment chamber 510 has a gas introduction port 511.
And a gas exhaust port 512 and a sample table 514 on which the Si wafer 513 is placed. For example, a gas containing HF is introduced from the gas introduction port 511 to remove the natural oxide film on the surface of the Si wafer 513, Gas containing HF gas exhaust port 5
It can be exhausted from 12. Further, the sample table 514
Is provided with a positive electrode 515 and a negative electrode 516.
The electric potential of the element formation surface 517 of the i-wafer 513 can be made lower than that of the positive electrode 515 which is installed facing each other.

Although not shown, this apparatus can transfer Si wafers between the pretreatment chamber 510 and the thermal oxidation chamber 520. In the thermal oxidation chamber 520, in addition to the gas introduction port 521 and the gas exhaust port 522, the Si wafer 10
A heater 523 that can heat up to 00 ° C. is provided, and a gas containing oxygen can be introduced from the gas introduction port 521 to perform thermal oxidation. (Twenty-first Embodiment) As a twenty-first embodiment, a thermal oxidation method of Si using the apparatus of FIG. 12 will be described.

First, the contamination of organic substances and the contamination of heavy metals on the surface of the Si wafer is confirmed by H ₂ SO ₄ / H ₂ O ₂ and HCl / H ₂ O _2.
It is removed by a wet process using a liquid or the like. By this treatment, a natural oxide film was formed on the wafer surface. Next, this wafer is placed on the sample stage 514 in the pretreatment chamber 510 shown in FIG. 12, the inside is replaced with nitrogen, and then HF gas diluted with nitrogen and CH ₃ OH are introduced from the gas inlet 511.
Gas was introduced and held for about 5 minutes.

Subsequently, the positive electrode 515 was biased with +0.5 V and the negative electrode 516 was biased with −0.5 V, and the sample was diluted with nitrogen while keeping the potential of the element formation surface more negative than that of the positive electrode 515. Exhausting HF gas and CH ₃ OH gas,
The inside of the pretreatment chamber 510 was replaced with nitrogen again. By these processes, the natural oxide film on the surface of the Si wafer was removed and covered with hydrogen.

Next, the Si wafer is treated with a gate valve 530.
Through the thermal oxidation chamber 520 whose interior is previously replaced with nitrogen.
Transported to. 900 Si wafers inside the thermal oxidation chamber 520
After heating to 0 ° C. and introducing oxygen gas diluted with nitrogen from the gas introduction port 521 and holding for about 60 minutes, the Si wafer was again conveyed to the pretreatment chamber 510 and taken out. By these treatments, a thermal oxide film having a thickness of about 3 nm was formed on the Si wafer surface. When the breakdown voltage of the thermal oxide film thus formed was measured, about 95% showed a breakdown voltage of 8 MV / cm or more.

On the other hand, in the natural oxide film removal treatment, the HF / N ₂ and CH ₃ OH gas was exhausted without applying a bias, and the value of the withstand voltage was extremely varied, and the value was about 2
0% was 8 MV / cm or less. It is considered that this is because fluorine remained on the surface when the natural oxide film was removed, and this fluorine deteriorated the film quality of the oxide film or made the thickness uneven. As described above, by using the method of this example, a high-quality Si thermal oxide film having a high withstand voltage could be formed.

In each of the thirteenth to twenty-first embodiments, an electrode is provided so as to face the sample and the potential of the sample is kept negative with respect to this electrode, but it is negative with respect to the ground potential or the container wall. You may hold so that. Further, the material for removing the natural oxide film is not limited to Si or Al alloy, but may be other semiconductor, metal, metal silicide, or the like. Further, as a method for removing the natural oxide film, an HF aqueous solution, NH ₄ F, NH _{4 is used.}
Other than Cl, HF / H ₂ O, HF / N ₂ + CH ₃ OH,
A gas, liquid or solid containing hydrogen halide may be used. Further, the processing after the removal of the natural oxide film is not limited to oxidation, deposition, crystal growth, and etching or impurity diffusion may be performed. Further, the surface from which the natural oxide film has been removed is covered with hydrogen, and this hydrogen is W as described in the embodiment.
Although it can be removed by reacting with a neutral gas such as F ₆ or by heating, it may be removed by light irradiation, electron irradiation, ion irradiation or the like.

[0105]

As described in detail above, by using the present invention, halogen on the surface of a semiconductor or a metal can be removed, the selectivity of selective CVD is improved, and contact holes or via holes with low contact resistance are buried. Further, the film quality of the thermal oxide film or the crystal can be improved, the uniformity of the impurity diffusion can be improved, and the electrical characteristics of the semiconductor element can be improved. In addition, since the corrosion of the wiring such as the Al alloy can be suppressed, the yield of manufacturing the semiconductor element is improved. Further, since it is possible to suppress the corrosion of the reaction container, the vacuum component, and the piping, it is possible to extend the life of these and to eliminate the leakage caused by the corrosion.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of a surface treatment apparatus used in a method of a first embodiment of the present invention,

2A to 2C are process cross-sectional views for explaining the first embodiment method,

FIG. 3 is a cross-sectional view showing a schematic configuration of a surface treatment apparatus used in the methods of the third to fifth embodiments,

FIG. 4 is a process sectional view for explaining a third embodiment method,

FIG. 5 is a cross-sectional view showing a schematic configuration of a surface treatment apparatus used in a sixth embodiment method,

FIG. 6 is a process sectional view for explaining a sixth embodiment method,

FIG. 7 is a process sectional view for explaining a method according to a seventh embodiment,

FIG. 8 is a sectional view showing a schematic configuration of a surface treatment apparatus according to a thirteenth embodiment,

FIG. 9 is a sectional view showing a schematic structure of a surface treatment apparatus according to a fourteenth embodiment,

FIG. 10 is a process sectional view for explaining the method of the fifteenth embodiment;

FIG. 11 is a sectional view showing a schematic configuration of a surface treatment apparatus according to a sixteenth embodiment,

FIG. 12 is a sectional view showing a schematic configuration of a Si thermal oxidation device according to a twentieth embodiment,

[Explanation of symbols]

10, 30, 50 ... Sample (substrate to be processed), 11, 51 ... Reaction vessel, 13, 35, 52 ... Sample stand, 15, 34, 39 ... Heater, 16, 37a, 38a, 53a, 53b ... Gas inlet, 17, 37b, 38b, 53c ... Gas exhaust port, 20, 40, 60, 70 ... Si substrate, 25, 41, 76 ... Natural oxide film, 26, 42 ... Halide layer, 31 ... Processing room, 32 ... Process room, 33 ... Gate valve, 36 ... electron beam source, 44, 64, 65, 66, 78 ... Contamination layer of Cl or F, 54 ... Discharge tube, 55 ... Waveguide.

Claims (3)

[Claims] 1. A surface of a substrate to be treated which has been subjected to a treatment process using a gas containing at least a halogen element, CO gas and NO.
A surface treatment method comprising contacting a gas and a gas containing at least one compound gas containing at least one of hydrogen element, CO and NO in the molecule. 2. A step of removing a natural oxide film formed on the surface of a substrate to be treated using a gas containing at least a halogen element, and then exposing the substrate to be treated to the atmosphere,
Contacting the surface of the substrate with CO gas, NO gas, and gas containing at least one compound gas containing at least one of hydrogen element, CO, and NO in the molecule, and then exposing the substrate to be treated to the atmosphere And a step of forming a predetermined thin film on the surface of the base body without any treatment. 3. A surface treatment method, which comprises irradiating an electron beam onto the surface of a substrate to be treated which has undergone a treatment step using a gas containing at least a halogen element.