JP4717335B2 - Film forming method, film, and element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a film forming method for forming a film having a composition containing Si, C, and N, and the obtained film and element.
[0002]
[Problems to be solved by the invention]
In recent years, an interlayer insulating film between ULSI wirings is changing from a conventional SiO ₂ film to a low dielectric constant film. Incidentally, an etching process is indispensable in the process of forming the semiconductor multilayer structure, but a stopper layer for stopping the etching reaction may be provided in the interlayer insulating film. Of course, this etching stopper layer is also required to have a lower dielectric constant than the conventional SiN film.
[0003]
Recently, it has been found that a film containing C, Si, and N has a lower dielectric constant than that of a SiN film and has a higher adhesion to a low dielectric constant film than that of a SiN film, thus providing a better etching stopper layer. I came.
[0004]
However, the technique for producing a film containing Si, C, and N has been poor.
For example, only a means of using (CH ₃ ) ₄ Si and NH ₃ and making it by a plasma chemical vapor deposition (P-CVD) method has been proposed.
[0005]
By the way, this technique has a problem that the raw material is a binary system. In addition, it has been difficult to control the composition of Si, C, and N in the film. Furthermore, it is pointed out that carbon (C) and nitrogen (N) in the film are decomposed, oxidized and burned. For this reason, the above technique has not been adopted in reality.
[0006]
And while carbon (C) and nitrogen (N) in the film are being examined for decomposition, oxidation, and combustion, the reason is that plasma CVD is because decomposition efficiency is too high. I came.
[0007]
Thus, although efforts have been made to lower the plasma power, the reproducibility is still poor, and it has been difficult to achieve a film with a targeted composition with plasma CVD.
[0008]
Furthermore, nanotechnology and micromachines are particularly expected today, and the technological progress in this field is remarkable. Today, thin films containing C, Si, and N are not only used in the conventional semiconductor field, but also in terms of their hardness and stability. It came to be expected that it could be applied to a wide range of fields such as microfabrication technology (device surface protection film, surface coating).
[0009]
Therefore, the first problem to be solved by the present invention is to provide a technique capable of forming a film having a composition containing Si, C, and N, particularly a film containing Si, C, and N in an arbitrary ratio. is there.
The second problem to be solved by the present invention is to provide a technique capable of forming a film having a composition containing Si, C, and N, particularly a film containing Si, C, and N in an arbitrary ratio by CVD. is there.
The third problem to be solved by the present invention is a technique capable of forming a film having a composition containing Si, C, and N, particularly a mixed film as intended containing Si, C, and N in an arbitrary ratio with good reproducibility. Is to provide.
[0010]
[Means for Solving the Problems]
The above-described problem is a method of providing a film having a composition containing Si, C, and N,
Solved by a film forming method characterized in that a film of a composition containing Si, C, and N is provided on a substrate disposed in a reaction chamber by allowing an aminosilicon compound vapor to exist in a reaction chamber having a heating element. Is done.
[0011]
In particular, the ratio between the number of Si atoms, the number of C atoms and the number of N atoms, when X: Y: Z is set to Si: C: N, X is 0.0000001 to 99.999999999, and Y is 0.0000001 to 99.9999999, a method of providing a film having a composition containing Si, C, and N in a range of Z from 0.0000001 to 99.9999999 (X + Y + Z = 100),
A film having a composition containing Si, C, and N is provided on a substrate disposed in a reaction chamber by allowing an aminosilicon compound vapor to exist in a reaction chamber having a heating body having a temperature of 800 ° C. or higher. This is solved by the film forming method.
[0012]
And according to the said film formation method, the mixed film containing Si, C, and N in arbitrary ratios is obtained with sufficient reproducibility.
[0013]
In the present invention, the heating element is preferably composed of one or more metal elements selected from the group of transition metals having a melting point of 1200 ° C. or higher. For example, selected from the group of W, Ta, Ti, Zr, Hf, V, Nb, Cr, Mo, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, and Pt Those composed of a material containing one or more metal elements are preferred. Among these, those composed of a material containing W and / or Ta are preferable. And such a heating body becomes like this. Preferably it is 800-3000 degreeC, More preferably, it is 1500 degreeC or more. In addition, it is preferable that it is 2500 degrees C or less. Of course, it is assumed that the heating element does not melt even when heated to such a temperature. And it is preferable that such a heating body is installed 1 cm or more away from the base | substrate which is going to form a film | membrane. In particular, it is preferable that they are arranged 2 cm or more, further 10 cm or more apart. In addition, it is preferable that an upper limit is 200 cm, ie, 200 cm or less. In particular, it is preferable that the distance is 100 cm or less, more preferably 30 cm or less. The substrate on which the film is formed is preferably kept at a temperature of 800 ° C. or lower, particularly 200 ° C. or lower. There is no particular restriction on the lower limit, but it is not necessary to make it lower than necessary. From this point, it may be room temperature or higher. That is, according to the present invention, the Si—C—N film can be formed by CVD without keeping the substrate at a high temperature. In this respect, it is significant that an Si—C—N film can be formed even on a substrate that does not have high heat resistance or must avoid high temperatures. For example, it is extremely convenient as a technique for providing a Si—C—N film on an electronic element such as a semiconductor element.
[0014]
The aminosilicon compound used in the present invention is particularly represented by SiR _x (NR ′ ₂ ) _4-x (where R is H or an alkyl group, R ′ is an alkyl group, and x is an integer from 0 to 3). It is a compound. Of these, tetrakisdimethylaminosilane (Si (NMe ₂ ) ₄ ), trisdimethylaminosilane (HSi (NMe ₂ ) ₃ ), bisdimethylaminosilane (H ₂ Si (NMe ₂ ) ₂ ), and dimethylaminosilane (H ₃ SiNMe ₂ ) are preferable. Is.
[0015]
In the present invention, the vapor of the aminosilicon compound is basically introduced into the reaction chamber. However, for example, hydrogen gas, nitrogen gas, or inert gas may be introduced. In particular, introduction of hydrogen gas is preferable.
[0016]
And the film | membrane obtained by the said film formation method is a film | membrane of the composition containing Si, C, and N. This is used in particular as a surface protective film. Among them, it is used as an etching stopper layer or an ion stopper layer. From this point, this film is particularly provided in an electronic device such as a semiconductor.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The film forming method according to the present invention is a method of providing a film having a composition containing Si, C, and N, and is disposed in a reaction chamber by allowing vapor of an aminosilicon compound to exist in a reaction chamber having a heating body. A film having a composition containing Si, C, and N on a substrate. In particular, the ratio between the number of Si atoms, the number of C atoms and the number of N atoms, when X: Y: Z is set to Si: C: N, X is 0.0000001 to 99.999999999, and Y is 0.0000001 to 99.9999999, a method of providing a film having a composition containing Si, C, and N in a range of Z from 0.0000001 to 99.9999999 (X + Y + Z = 100), and a reaction having a heating body having a temperature of 800 ° C. or higher This is a method of providing a film having a composition containing Si, C, and N on a substrate disposed in a reaction chamber by causing an aminosilicon compound vapor to exist in the chamber. This film forming method is based on CVD. And it is the method of obtaining the mixed film which contains Si, C, and N in arbitrary ratios.
[0018]
In the present invention, the heating element is composed of one or more metal elements selected from the group of transition metals having a melting point of 1200 ° C. or higher. For example, it is selected from the group of W, Ta, Ti, Zr, Hf, V, Nb, Cr, Mo, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, and Pt. It is made of a material containing one or more metal elements. Especially, it is comprised with the material containing W and / or Ta.
[0019]
In the present invention, the heating body is preferably heated to 800 to 3000 ° C. In particular, it is heated to 1500 ° C. or higher. And it is 2500 degrees C or less especially. And such a heating body is installed 1 cm or more away from the base | substrate which is going to form a film | membrane. In particular, they are arranged at a distance of 2 cm or more, further 10 cm or more. The upper limit is 200 cm, that is, 200 cm or less. In particular, it is 100 cm or less, and further 30 cm or less.
[0020]
In the present invention, the substrate on which the film is formed is kept at a temperature of 800 ° C. or lower, particularly 200 ° C. or lower. There is no particular restriction on the lower limit, but it is not necessary to make it lower than necessary. From this point, it is room temperature or higher.
[0021]
The aminosilicon compound used in the present invention is particularly represented by SiR _x (NR ′ ₂ ) _4-x (where R is H or an alkyl group, R ′ is an alkyl group, and x is an integer from 0 to 3). It is a compound. Among them, tetrakisdimethylaminosilane (Si (NMe ₂ ) ₄ ), trisdimethylaminosilane (HSi (NMe ₂ ) ₃ ), bisdimethylaminosilane (H ₂ Si (NMe ₂ ) ₂ ), and dimethylaminosilane (H ₃ SiNMe ₂ ). .
[0022]
In the present invention, basically, a vapor of an aminosilicon compound is introduced into a reaction chamber. However, for example, hydrogen gas, nitrogen gas, or inert gas may be introduced. In particular, the film obtained by the above method in which hydrogen gas is introduced is used as a surface protective film. In particular, it is used as an etching stopper layer. Alternatively, it is used as an ion stopper (blocking ion passage) layer. From such characteristics, the film obtained by the above method is provided in an electronic element such as a semiconductor.
Hereinafter, specific examples will be described.
[0023]
[Example 1]
The CVD apparatus shown in FIG. 1 was used. 1 is an apparatus for forming a film by a chemical vapor deposition method. 1 is a reaction chamber, 2 is a heating body (Ta filament), 3 is a substrate table, 4 is a substrate, 5 is a raw material ( Aminosilicon compound) container, 6 is a raw material gas introduction mechanism, 7 is a flow rate controller, and 8 is a pipe.
[0024]
First, (HSi (NMe ₂ ) ₃ ) was fed into the reaction chamber 1 by the source gas introduction mechanism 6. The trisdimethylaminosilane partial pressure during growth was set to 20 Pa.
N-type Si (001) was used as the substrate 4. The substrate temperature was kept at room temperature.
The heating element 2 is maintained at 1800 ° C. by passing an electric current.
[0025]
Then, trisdimethylaminosilane was acted on by the heating body and deposited on the substrate 4 set at a position 20 cm away from the heating body 2 to form a thin film.
[0026]
This thin film was 0.096 μm thick and amorphous with a composition of Si—C—N.
When this film was etched with a general interlayer insulating film (low dielectric constant film) using a dry etching gas, the etching rate was three times or more slower than that of the low dielectric constant film. That is, it turns out that it is a favorable etching stopper film | membrane.
It was also found that the dielectric constant is lower than SiN.
Further, the adhesion to the SiO-based dielectric film containing an organic group was also superior to that of the SiN film.
[0027]
[Example 2]
In Example 1, it carried out similarly except having used the filament made from W instead of the filament made from Ta as a heating body.
[0028]
As a result, the obtained thin film was also amorphous with a composition of Si—C—N.
When this film was etched with a general interlayer insulating film (low dielectric constant film) using a dry etching gas, the etching rate was three times or more slower than that of the low dielectric constant film. That is, it turns out that it is a favorable etching stopper film | membrane.
It was also found that the dielectric constant is lower than SiN.
Further, the adhesion to the SiO-based dielectric film containing an organic group was also superior to that of the SiN film.
[0029]
[Comparative Examples 1 and 2]
In Examples 1 and 2, the heating was performed without generating heat. However, the substrate 4 was heated to 400 ° C.
However, no film was formed on the substrate 4.
[0030]
[Example 3]
In Example 1, except for using H ₂ Si (NMe _{2) 2} in place of HSi (NMe _{2) 3} was carried out in the same manner.
[0031]
The thin film obtained as a result was also amorphous with a composition of Si—C—N.
When this film was etched with a general interlayer insulating film (low dielectric constant film) using a dry etching gas, the etching rate was three times or more slower than that of the low dielectric constant film. That is, it turns out that it is a favorable etching stopper film | membrane.
It was also found that the dielectric constant is lower than SiN.
Further, the adhesion to the SiO-based dielectric film containing an organic group was also superior to that of the SiN film.
[0032]
[Example 4]
In Example 1, except for using _H 3 SiNMe ₂ instead of HSi (NMe _{2) 3} was carried out in the same manner.
[0033]
The thin film obtained as a result was also amorphous with a composition of Si—C—N.
When this film was etched with a general interlayer insulating film (low dielectric constant film) using a dry etching gas, the etching rate was three times or more slower than that of the low dielectric constant film. That is, it turns out that it is a favorable etching stopper film | membrane.
It was also found that the dielectric constant is lower than SiN.
Further, the adhesion to the SiO-based dielectric film containing an organic group was also superior to that of the SiN film.
[0034]
[Example 5]
In Example 1, except for using the Si (NMe _{2) 4} instead of HSi (NMe _{2) 3} was carried out in the same manner.
[0035]
The thin film obtained as a result was also amorphous with a composition of Si—C—N.
When this film was etched with a general interlayer insulating film (low dielectric constant film) using a dry etching gas, the etching rate was three times or more slower than that of the low dielectric constant film. That is, it turns out that it is a favorable etching stopper film | membrane.
It was also found that the dielectric constant is lower than SiN.
Further, the adhesion to the SiO-based dielectric film containing an organic group was also superior to that of the SiN film.
[0036]
[Example 6]
In Example 1, the same procedure was performed except that H ₂ was further fed into the reaction chamber 1 at a flow rate of 5 sccm.
[0037]
The thin film obtained as a result was also amorphous with a composition of Si—C—N. However, the ratio of C and N was lower than that of Example 1.
When this film was etched with a general interlayer insulating film (low dielectric constant film) using a dry etching gas, the etching rate was three times or more slower than that of the low dielectric constant film. That is, it turns out that it is a favorable etching stopper film | membrane.
It was also found that the dielectric constant is lower than SiN.
Further, the adhesion to the SiO-based dielectric film containing an organic group was also superior to that of the SiN film.
[0038]
[Example 7]
In Example 1, it carried out similarly except having set the temperature of the heating body to 1500 degreeC.
[0039]
The thin film obtained as a result was also amorphous with a composition of Si—C—N.
When this film was etched with a general interlayer insulating film (low dielectric constant film) using a dry etching gas, the etching rate was three times or more slower than that of the low dielectric constant film. That is, it turns out that it is a favorable etching stopper film | membrane.
It was also found that the dielectric constant is lower than SiN.
Further, the adhesion to the SiO-based dielectric film containing an organic group was also superior to that of the SiN film.
[0040]
[Example 8]
In Example 1, it carried out similarly except having set the temperature of the heating body to 2500 degreeC.
[0041]
The thin film obtained as a result was also amorphous with a composition of Si—C—N.
When this film was etched with a general interlayer insulating film (low dielectric constant film) using a dry etching gas, the etching rate was three times or more slower than that of the low dielectric constant film. That is, it turns out that it is a favorable etching stopper film | membrane.
It was also found that the dielectric constant is lower than SiN.
Further, the adhesion to the SiO-based dielectric film containing an organic group was also superior to that of the SiN film.
[0042]
【The invention's effect】
A film having a composition containing Si, C, and N used as an etching stopper, an ion stopper, or a surface protective film can be formed with good reproducibility.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an entire film forming apparatus (CVD) according to the present invention.
DESCRIPTION OF SYMBOLS 1 Reaction chamber 2 Heating body 3 Substrate holder 4 Substrate 5 Raw material container 6 Raw material gas introduction mechanism 7 Flow rate controller 8 Pipe

Claims (13)

A method of providing a film having a composition containing Si, C, and N,
In a reaction chamber having a heating body having a temperature of 800 ° C. or higher , SiR _x (NR ′ ₂ ) _4-x (where R is H or an alkyl group, R ′ is an alkyl group, x is an integer from 0 to 3) A film forming method comprising: forming a film having a composition containing Si, C, and N on a substrate disposed in a reaction chamber by the presence of a vapor of an aminosilicon compound. Ratio between the number of Si atoms, the number of C atoms and the number of N atoms When Si: C: N is X: Y: Z, X is 0.0000001 to 99.9999999, and Y is 0.0000001 to 99.99. The film forming method according to claim 1, wherein the film forming method is a method of providing a film having a composition containing Si, C, and N in a range of 9999999, Z of 0.0000001 to 99.9999999 (X + Y + Z = 100). The film forming method according to claim 1 or 2, wherein the film is formed by a chemical vapor deposition method. The film formation according to any one of claims 1 to 3, wherein the heating element is made of one or more metal elements selected from the group of transition metals having a melting point of 1200C or higher. Method. The film forming method according to any one of claims 1 to 4 , wherein the heating element is made of one or more selected from W and Ta . The film forming method according to any one of claims 1 to 5, wherein the substrate on which the film is formed is maintained at a temperature of 800C or lower . The aminosilicon compound is one or more compounds selected from the group consisting of tetrakisdimethylaminosilane, trisdimethylaminosilane, bisdimethylaminosilane, and dimethylaminosilane. 6. Any one of the film forming methods. 8. The film forming method according to claim 1, wherein hydrogen gas other than the aminosilicon compound vapor is introduced into a reaction chamber having a heating element . The film forming method according to any one of claims 1 to 8, characterized in that a film having a composition containing Si, C, and N used as a surface protective film is provided . 10. The film forming method according to claim 1, which is a method of providing a film having a composition containing Si, C, and N used as an etching stopper layer.   10. The film forming method according to claim 1, which is a method of providing a film having a composition containing Si, C, and N used as an ion stopper layer. It is formed by the film forming method according to claim 1.
A film having a composition containing Si, C, and N. An element comprising a film formed by the film forming method according to any one of claims 1 to 11 .

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