JP3195171B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates relates to a method of manufacturing a semiconductor device, in particular, SiO ₂ containing the F on a semiconductor substrate
And a method for forming an insulating film mainly containing.

[0002]

2. Description of the Related Art In a semiconductor device, an insulating film for electrically isolating element wires is used. Conventionally, as the insulating film, a SiO ₂ film formed by oxidizing a Si substrate by a thermal oxidation method or a chemical vapor deposition (CVD) method using a gas such as monosilane or tetraethoxysilane (TEOS) as a raw material is used. The SiO ₂ film formed by using the method is mainly used. In particular, a SiO ₂ film formed by plasma CVD using TEOS and O ₂ is used for insulating the Al wiring because it can be formed at a low temperature of about 400 ° C.

[0003] In recent years, with the miniaturization of elements, delay in signal transmission has been concerned. This is a problem in that the spacing between the wirings is reduced due to the miniaturization of the element, so that the capacitance between the wirings is increased and the transmission of the electric signal is delayed. The signal transmission delay hinders high-speed operation of the semiconductor device and is one of the factors hindering performance improvement. Therefore, it is necessary to reduce the dielectric constant of the insulating film interposed between the wirings as much as possible.

It has been found that the relative dielectric constant of a SiO ₂ film formed by a conventional plasma CVD method is 4.0 to 5.0. Therefore, attempts have been made to add F to SiO ₂ in order to lower the relative dielectric constant of the SiO ₂ film.

For example, it is known that the relative dielectric constant of SiO ₂ is reduced by implanting F into SiO ₂ by ion implantation (Japanese Patent Application Laid-Open No. 2-77127).

However, in this method, the implantation amount of F needs to be 1 × 10 ¹⁹ atoms / cm ³ or more.
It takes a long time to form. In addition, after driving F
A step of activating F in SiO ₂ by heat treatment at 0 ° C. or higher is indispensable, and cannot be used as an insulating film on Al wiring.

Further, room temperature CVD using FSi (OC ₂ O ₅ ) ₃ and H ₂ O has been attempted. (T. Honm
a et al. , IEEE IEDM, pp. 289
(1991)).

However, in this method, it is difficult to control the F concentration of SiO ₂ , and the formed SiO 2
There is a problem that the hygroscopicity of the _two films is high.

Further, hydrofluorosilicic acid (H ₂ Si
A method is known in which a boric acid aqueous solution or the like is added to a supersaturated aqueous solution of F ₆ ), and a SiO ₂ film is formed therein. According to this method, it is reported that F is contained in the film at about 5 mol%, and the relative dielectric constant is smaller than 3.9 of the thermally oxidized SiO ₂ film (Japanese Patent Application Laid-Open No. 3-97247).

However, in this method, it is difficult to control the F concentration in SiO ₂ and the growth rate is 1 nm.
/ Min, which is very slow.

Further, formation of a SiO ₂ film to which F is added by a parallel plate type plasma CVD apparatus using TEOS, O ₂ and C ₂ F ₆ has been reported (T. Usami).
et al. , ICSSDM, pp. 146-157. 161 (199
3), Proceedings of the 41st Joint Lecture Meeting on Applied Physics,
p. 780 (1994)).

However, the relative dielectric constant of the formed SiO ₂ cannot be reduced to 3.6 or less, and there is a problem that the hygroscopicity is high.

Further, formation of a SiO ₂ film to which F is added by using an ECR type plasma CVD apparatus using SiF ₄ and O ₂ has been reported (1993 ICSSDM, pp. 139-143).
158 (1993)).

However, in this method, although the etching resistance to the buffered hydrofluoric acid aqueous solution can be as high as that of the SiO ₂ film by thermal oxidation, it is difficult to control the F concentration in SiO _2. There's a problem.

Moreover, in this case, since ions having high ion energy are incident on the substrate, impurities are implanted into the Al wiring provided on the underlying substrate to induce corrosion, increase electric resistance, and cause SM (stress migration). , EM (Electromigration) and the like. Also,
There is a problem that the upper portion of the underlying Al wiring is etched or the transistor structure is damaged, and the semiconductor element does not operate.

[0016]

As described above, when the distance between the wirings is reduced due to the miniaturization of the element, there is a problem that the capacitance between the wirings increases and a signal delay occurs.

Attempts have been made to lower the dielectric constant of the insulating film by introducing F into SiO ₂ , and various methods of forming an SiO ₂ film containing F have been proposed, but the drawbacks are also remarkable. There is nothing to be loved yet.

The present invention has been made in view of the above circumstances, and a first object of the present invention is to contain fluorine, which is superior to the conventional one (particularly excellent in hygroscopicity), and contains SiO ₂ as a main component. It is an object of the present invention to provide a method of manufacturing a semiconductor device including a step of forming an insulating film.

A second object of the present invention is to provide a method of manufacturing a semiconductor device including a step of forming an insulating film containing fluorine and containing SiO ₂ as a main component, which can reduce an adverse effect on a base. is there.

[0020]

To achieve the above first object, according to the Invention The method of manufacturing a semiconductor device according to the present invention (claim 1), on the processed substrate, includes fluorine, a SiO ₂ primary When forming an insulating film as a component, as a raw material of the insulating _{film, Si x H y (x ≧} 1,0 ≦ y ≦ 2x + 2), using a fluorine raw material containing an oxygen source and a fluorine containing oxygen, and the three At least one of the raw materials is an ion having an ion energy of 10 eV or more.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising:
Upon the iO ₂ to form an insulating film mainly supplies the argon ions to the substrate to be treated, as a material of the insulating _{film, Si x H y (x ≧} 1,0 ≦ y ≦ 2x
+2) An oxygen source containing oxygen and a fluorine source containing fluorine are used, and at least one of the three sources is an ion having an ion energy of 10 eV or more.

Here, when the fluorine source is an ion containing fluorine ions, the ion energy is 100 eV.
It is desirable that:

When the underlayer is Al, the film forming temperature is set to 5
It is desirable that the temperature be not higher than 00 ° C. Further, according to another method of manufacturing a semiconductor device according to the present invention (claim 3), in the above-described invention (claims 1 and 2), the insulating film has a degree of vacuum of 1 × 10 ⁻² Torr or less; Plasma density of 1
× 10 ¹¹ cm ^-3 or more plasma (HDP: High Density
Prasma) characterized by being formed in an atmosphere.

Preferred embodiments of the present invention are as follows.

The Si _x H _y cation of n (n is a natural number), i.e., a Si _x H _y ^{n +.} The power (discharge power) of a high-frequency power supply used for generating plasma is FM-modulated or AM-modulated.

The bias voltage applied to the substrate to be processed is FM
Modulation or AM modulation, or a bias voltage such as a rectangular DC bias or a triangular DC bias is applied to the substrate to be processed.

The Si / F ratio is varied during film formation.

The pressure is varied during the film formation.

The temperature is varied during the film formation.

The method for generating plasma having a plasma density of 1 × 10 ¹¹ cm ⁻³ or more includes magnetron discharge, cyclotron resonance, inductive coupling, capacitive coupling, helicon wave,
Use any of electron beam impact.

Further, another method of manufacturing a semiconductor device according to the present invention (Claim 4) is directed to the above-described invention (Claims 1 and 2).
In, x is from is characterized by using two or more Si _x H _y.

Further, another method of manufacturing a semiconductor device according to the present invention (Claim 5) is directed to the above-described invention (Claims 1 and 2).
In, as the fluorine raw material, using an ion containing fluorine, and wherein said mass than Si _x H _y is large.

Further, another method of manufacturing a semiconductor device according to the present invention (Claim 6) is a method for manufacturing a semiconductor device according to the present invention (Claims 1 and 2).
, At least two of the three raw materials are excited, and the method of exciting at least one raw material is different from that of the other raw materials.

Further, another method of manufacturing a semiconductor device according to the present invention (claim 7) is a method for manufacturing a semiconductor device in an atmosphere having a degree of vacuum of 1 × 10 ⁻² Torr or less and a plasma density of 1 × 10 ¹¹ or more.
When forming an insulating film containing fluorine and containing SiO ₂ as a main component on the substrate to be processed, supplying ions for forming the insulating film to the substrate to be processed while increasing the ion energy thereof. A feature is provided.

Further, another method of manufacturing a semiconductor device according to the present invention (claim 8) is a method of manufacturing a semiconductor device in an atmosphere having a degree of vacuum of 1 × 10 ⁻² Torr or less and a plasma density of 1 × 10 ¹¹ or more.
When forming an insulating film containing fluorine and SiO ₂ as a main component on the substrate to be processed, the fluorine raw material containing fluorine is supplied to the substrate to be processed while increasing the flow rate thereof. .

[0036]

According to the study of the present inventors, it has been found that fluorine-containing Si
The O ₂ in forming the insulating film mainly containing, as a material of the insulating _{film, Si x H y (x ≧} 1,0 ≦ y ≦ 2x +
2) using an oxygen source containing oxygen and a fluorine source containing fluorine, and at least one of the three sources is:
It was found that an ion having an ion energy of 10 eV or more can form an insulating film having better hygroscopicity than before.

Therefore, according to the present invention based on the above findings (claims 1 to 6), it is superior to the conventional one (particularly excellent in hygroscopicity), contains fluorine, and contains SiO ₂ as a main component. An insulating film having a low dielectric constant can be formed.

According to the study by the present inventors, the degree of vacuum is 1 × 10 ⁻² Torr or less and the plasma density is 1 × 1 Torr.
When an insulating film containing fluorine and containing SiO ₂ as a main component is formed in an atmosphere of 0 ¹¹ cm ⁻³ or more, the film is formed while increasing the ion energy of ions used for forming the insulating film. It has been found that the adverse effect (damage) on the base can be reduced as compared with the related art. It was also found that when the ion energy at the start of film formation was 100 eV or less, damage to the underlayer was particularly reduced.

Therefore, according to the present invention (claim 7) based on the above findings, while suppressing damage to the base,
An insulating film containing fluorine and having SiO ₂ as a main component and having a low dielectric constant can be formed.

According to the study by the present inventors, the degree of vacuum was 1 × 10 ⁻² Torr or less and the plasma density was 1 × 1 Torr.
When an insulating film containing fluorine and SiO ₂ as a main component is formed in an atmosphere of 0 ¹¹ cm ⁻³ or more, the film is formed while increasing the flow rate of the fluorine material containing fluorine. It was also found that the adverse effect (damage) on the substrate can be reduced.

Therefore, according to the present invention based on the above findings (Claim 8), while suppressing damage to the base,
An insulating film containing fluorine and having SiO ₂ as a main component and having a low dielectric constant can be formed.

[0042]

Embodiments will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic diagram showing a schematic configuration of a thin film forming apparatus according to a first embodiment of the present invention. This thin film forming apparatus is roughly composed of a reaction vessel 10 used for a film deposition reaction by a CVD method, and a gas supply system vessel 20 for supplying a gas into the reaction vessel 10.

In the reaction vessel 10, a substrate support 12 on which a substrate 11 to be processed is placed is accommodated. Substrate support 12
Is provided with a heater 13 for heating the substrate 11 to be processed and a cooling pipe 15 for circulating a coolant, and the heater 13 and the cooling pipe 15 can keep the substrate 11 at a constant temperature. Has become. Further, the reaction vessel 10 can be evacuated by a vacuum pump 16. The reaction vessel 10 is provided with deflectors 14a, 14b, 14c, and 14d for supplying only the neutral gas from the gas to be introduced to the substrate 11 to be processed.

On the other hand, the gas supply system container 20 is provided with four sets of gas introduction systems for exciting gas to take out arbitrary particles and supply the particles into the reaction container 10. The first gas introduction system includes an ion source 21a provided in contact with the outer wall of the container 20, an extraction electrode 22a for extracting ions,
Focusing lenses 23a and 24 for focusing the extracted ions
a, a mass filter 25a that separates a gas by using a difference in a track corresponding to a ratio of a mass of a substance passing through an electric field to a retained charge, a speed reducer 26a that decelerates the separated gas, and A gas is supplied into the reaction container 10 from the neutralization chamber 27a. Also, the second, third, and fourth gas introduction systems are similar to the first gas introduction system in that the ion source (2
1b, 21c, 21d) and extraction electrodes (22b, 22
c, 22d), a focusing lens (23b, 23c, 23d,
24b, 24c, 24d), mass filter (25b, 2
5c, 25d), reducers (26b, 26c, 26d),
And a neutralization chamber (27b, 27c, 27d). The inside of the container 20 is evacuated to about 10 ^-6 Torr by a vacuum pump (not shown).

Next, a method for forming an insulating film mainly containing F ₂ containing SiO ₂ using this thin film forming apparatus will be described.

First, monosilane (Si) is supplied to the ion source 21a.
H ₄ ) gas, oxygen (O ₂ ) gas to the ion source 21b,
A carbon tetrafluoride (CF ₄ ) gas is introduced into the ion source 21c. A microwave having a frequency of 2.45 GHz is applied to each of the ion sources 21a, 21b, 21c, and 21d from a high-frequency power supply (not shown) to 800 W, and each gas is ionized. For example, SiH ₄ is Si ⁺ , SiH ⁺ , S
iH ₂ ^+, SiH ₃ ^+, an SiH ₄ ⁺ or the like, 0 ₂ O
⁺ , O ₂ ^+, etc., and CF ₄ is F ⁺ , CF ⁺ , CF
₂ ⁺ , CF ₃ ⁺ , CF ₄ ^{+ and the} like.

Here, the extraction electrodes 22a, 22b, 2
A voltage of, for example, -100 V is applied to 2c to extract each ion.

Thus, each ion accelerated to 100 to several hundreds eV is focused on the focusing lenses 23a, 23b, 23c,
An ion beam having a diameter of about 15 mm is formed at 24a, 24b and 24c. This ion beam is applied to the mass filter 25a,
It flies in an electric field into 25b and 25c, and follows each track by (mass / charge).

Therefore, by appropriately selecting the electric field intensity, ions having an arbitrary mass and charge can be separated and guided to the speed reducers 26a, 26b and 26c.

The separated ions can be set to a desired ion energy in the speed reducer. Also,
Each ion reaches the substrate after passing through the neutralization chambers 27a, 27b, and 27c. At this time, the ions can be electrically neutralized and then introduced into the reactor 10.

The ions that have not been neutralized are bent by the electric field applied to the deflectors 14a, 14b and 14c and cannot reach the substrate. As described above, in the thin film forming apparatus used in this embodiment, it is possible to cause specific particles to enter the substrate as ions having specific energy or as electrically neutral particles.

The conditions for ionizing the gas in the ion sources 21a, 21b, 21c (the amount of introduced gas, the pressure at the time of discharge, the applied power of microwaves, etc.) are changed to introduce the gas into the reaction vessel 10. It is also possible to control the number of particles that do.

FIGS. 2A to 2C show an example in which O and CF ₃ as neutrons and SiH ₃ ⁺ as neutral particles or ions are incident on a substrate to form an interlayer insulating film of a multilayer wiring. This will be described with reference to the process sectional views.

First, the Si substrate 31 is set on the substrate support 12 and heated to 400 ° C. by the resistance heater 13. In the vacuum vessel 10, O and CF ₃ as neutral particles,
SiH ₃ ⁺ is simultaneously introduced as neutral particles or ions, and the pressure is set to 5 × 10 ⁻³ Torr. At this time, the substrate support 12 is grounded. Thus, as shown in FIG. 2A, the 500 nm SiO ₂ film 3 is formed on the Si substrate 31.
2 is deposited.

Next, as shown in FIG. 2B, a 400 nm Al film is formed by DC magnetron sputtering, and is patterned to have a width of 500 nm and a height of 400 n.
An m-th first-level Al wiring 33 is formed.

Thereafter, as shown in FIG. 2C, an 800 nm SiO ₂ film 34 is formed by the same method as described above. Further, a 400 nm Al film is formed and patterned in the same manner as above to form a second layer Al wiring 35, and then an 800 nm SiO ₂ film 36 is formed by the same film forming method as described above.

FIG. 3 shows that SiH ₃ ⁺ (ion energy:
5eV) shows an infrared absorption spectrum (FT-IR spectrum) of a film formed by + O + CF ₃ . Note that the substrate temperature was 400 ° C. and the film forming pressure was 5 × 10 ⁻³ Torr.

In the vicinity of 3700 cm ^-1 , Si-OH, 340
0cm in the vicinity of ^-1 H-OH, in the vicinity of 1080cm ^-1 Si-
O stretching vibration, Si-F around 940 cm ^-1 , 800 cm
Each peak of Si—O bending vibration is observed at around ⁻¹ and 450 cm ⁻¹ .

Hereinafter, the F concentration in the film is determined by the ratio of the integrated value of the spectrum of Si—F and the spectrum of Si—O stretching vibration (Si—
F / Si-O). The amount of water in the film is S
Sum of integrated values of i-OH and H-OH spectra and Si-
Ratio of integrated value of spectrum of O stretching vibration (Si-OH + H
-OH / Si-O).

When the supply amounts of Si ⁺ (ion energy: 5 eV) and O to the substrate are fixed and the supply amount of CF ₃ is changed, the amount of F contained in the film, that is, the F concentration in the film ( Si-FO / Si-O) monotonically increased as shown in FIG.

FIG. 5 shows the relationship between the F concentration in the film (Si-FO / Si-O) and the relative dielectric constant. The relative dielectric constant was determined from CV characteristics of a MOS capacitor formed of SiO ₂ to which F was added and formed on an Si substrate and an Al electrode film patterned to about 0.1 mm ² . As the F concentration in the film increases, the relative permittivity monotonously decreases.

FIGS. 6 and 7 show neutral particles or ions to be supplied to the substrate as Si ⁺ , SiH ⁺ , and SiH _2.
⁺ , SiH ₃ ⁺ , F ₂ added SiO ₂ film formed by changing the energy of SiH ₄ ⁺ is included in the film immediately after film formation and after one week of standing in air (temperature 25 ° C., humidity 50%). The amount of water, that is, the amount of moisture absorption ((Si-OH + HO
3 shows the relationship between H) / Si—O) and ion energy.

Regardless of which ion was supplied, it was found that when the ion energy was 10 eV or less, the water concentration in the film increased.

The F concentration in the film was changed by changing the supply amount of the CF ₃ neutral particles while setting the ion energy to 10 eV or more.

FIG. 8 shows the relationship between the F concentration in the film at that time and the amount of moisture absorbed after one week in air. FIG. 8 shows the F concentration (Si-FO / Si-O) in the film and the hygroscopicity ((S
The relationship regarding (i-OH + HOH) / Si-O) is also shown.

According to JP-A-5-164831, the F
At a high concentration of 8 at% or more, the amount of moisture absorption after leaving in the air increases, but in the thin film deposition method of the present invention, even when F is present in the film at a high concentration, moisture absorption after leaving in the air is observed. I understand that there is no.

In Japanese Patent Application Laid-Open No. H5-164831, at% is used as a display unit of the F concentration in the film. In the present embodiment, the F concentration in the film is represented by the spectrum of Si—F in the FT-IR spectrum. And the ratio (Si-F / Si-O) of the integral value of the spectrum of the Si-O stretching vibration.

Therefore, when the amount of F in the film was quantified by the fluorescent X-ray method, it was found that the F concentration in the film obtained from the FT-IR spectrum could be converted to at% by almost doubling the F concentration. Therefore, in FIG. 8, the F concentration (at%) in the film in the report of JP-A-5-164831 is shown.
Is also shown by multiplying by １ ／.

In this embodiment, the ions are Si ⁺ , SiH ⁺ , SiH ₂ ⁺ , SiH ₃ ⁺ , and SiH _4.
⁺ Was changed and supplied to the substrate.
Si _x H _y ^{n +} ions (x ≧ 1,0 ≦ y ≦ 2x + 2, n ≧ 2) the same effect be used that is generated by discharging the ₄ were obtained.

In this embodiment, O and CF ₃ are used as neutral particles. However, neutral particles containing at least O generated when O ₂ is discharged are used instead of O. In addition, F, CF, C instead of CF ₃
Similar effects were obtained by using neutral particles containing at least F generated when CF ₄ was discharged, such as F ₂ and CF ₄ .

In this embodiment, the ions are S
i ⁺ , SiH ⁺ , SiH ₂ ⁺ , SiH ₃ ⁺ , SiH ₄ ⁺
Was supplied to the substrate by changing the energy of O ₂ , but O ⁺ , O ₂ ^+, etc. generated when O ₂ was discharged as ions were supplied to the substrate by changing the ion energy, and SiH ₄ was used as neutral particles. Si _x H _y generated when discharging
Neutral particles or Si _x H _y ^{n +} ions (x ≧ 1,0 ≦ y
≦ 2x + 2, n ≧ 1), and neutral particles containing at least F such as F, CF, CF ₂ , CF ₃ , CF _4, etc. generated when CF ₄ is discharged, F
The same effect was obtained when the ion energy was 10 eV or more also in the case of forming a SiO ₂ film to which was added.

[0073] In addition, further, Si _x H _y ^{n +} ions generated at the time of discharging the _{SiH 4 (x ≧ 1,0 ≦ y} ≦ 2x +
2, n ≧ 1), and ions containing at least O generated when discharging O ₂ are supplied, and only particles containing at least F generated when discharging CF ₄ are electrically charged. The same effect was obtained even when the energy was supplied in a neutral state as long as the energy of at least one of the ions was 10 eV or more.

Next, F generated when CF ₄ is left unattended
⁺ , CF ⁺ , CF ₂ ⁺ , CF ₃ ⁺ , and at least one of ions containing at least F typified by CF ₄ ⁺ ions, which are supplied to the substrate while changing the energy, and discharged when SiH ₄ is discharged. is the Si _x H _y neutral particles (x ≧ 1, 0 ≦
y ≦ 2x + 2) and the case where any one of neutral particles containing at least O generated when O ₂ is discharged is supplied to the substrate.

Regardless of the F concentration in the film, a good film which does not absorb moisture after standing in the air can be obtained regardless of the magnitude of the F concentration in the film, regardless of the ion energy including F at least. Was.

However, when the ion energy was 100 eV or more, no film was deposited. This is F
It is considered that the deposition of the thin film did not proceed due to the etching effect of the silicon.

In addition to ions containing at least F (ion energy of 10 eV or more and 100 eV or less), particles containing at least O are ionized or electrically neutral, and particles containing at least Si. Was supplied to the substrate in an ionically or electrically neutral state, the deposited F-added SiO ₂ film did not show a moisture absorption phenomenon after being left in the air.

However, when F ⁺ ions are supplied as ions containing at least F, film deposition hardly occurs.

Further, as an ion containing at least F, C
When F ⁺ ions are supplied, film deposition hardly occurs even when SiH _x ⁺ (x = 1, 2, 3) is supplied as ions containing at least Si.

From this, in order to deposit a SiO ₂ film containing F, at least the mass of ions containing F must be S
It is preferable to large mass Si _x H _y ^{n +} ions produced upon discharge _{iH 4 (x ≧ 1,0 ≦ y} ≦ 2x + 2, n ≧ 1).

[0081] This is in order to deposit the SiO ₂ film containing F, the ion energy of ions including at least F, Si _x H _y generated upon discharging SiH ₄
^This is considered to indicate that it is desirable to be smaller than the ion energy of ^{n +} ions (x ≧ 1, 0 ≦ y ≦ 2x + 2, n ≧ 1).

Next, the results of forming a film by changing the degree of vacuum during the film formation are shown below.

The results described so far indicate that the degree of vacuum is 5 × 1
The film was formed at 0 ^-3 Torr, and the F-added SiO ₂ film was formed by changing the degree of vacuum at the time of film formation, and the amount of moisture absorption after standing in the air was examined.

SiH ₃ ⁺ was supplied to the substrate at 20 eV as ions, and CF ₃ and O as neutral particles were supplied to the substrate. At this time, the film was formed by adjusting the supply amount of CF _{3 to} the substrate so that the F concentration in the film was 4% by examining the spectrum of FT-IR.

The formed F-added SiO ₂ film was left in the air for one week, and the pressure and moisture absorption ((Si—OH + HO)
H) / Si—O) are shown in FIG.

From the results shown in FIG. 9, the reaction vessel 1 during the film formation was obtained.
It was found that it was necessary to form a film at a degree of vacuum within 0 at 1 × 10 ⁻² Torr or less. Further, this result did not depend on the F concentration in the film.

The above results indicate that the ions are S
iH ₃ ⁺ at 20 eV, CF ₃ and O as neutral particles
While those supplied to the substrate, Si _x H _y neutral particles or Si _x H _y ⁿ are generated at the time of discharging the SiH ₄ ⁺
(X ≧ 1, 0 ≦ y ≦ 2x + 2, n ≧ 1), neutral particles or ions containing at least O generated when O ₂ is discharged, and generated when CF ₄ is discharged. When neutral particles or ions containing at least F are supplied to form an insulating film mainly containing SiO ₂ containing F, at least one or a plurality of ions are ions, and Is 10 eV or more, the degree of vacuum in the reaction vessel 10 during film formation is 1 × 10
^{When the} pressure was ⁻² Torr or less, an F-added SiO ₂ film showing no hygroscopicity was similarly obtained after standing in air.

Further, the results of film formation by changing the temperature of the substrate at the time of film formation by the heater 13 and the cooling pipe 15 provided in the substrate support table 12 shown in FIG. 1 are shown below.

The results described so far indicate that the film formation temperature is 40
Although the film was formed at 0 ° C., the F-added SiO ₂ film was formed by changing the substrate temperature at the time of film formation, and the moisture absorption was examined after standing in the air. SiH ₃ ⁺ at 20 eV as ions,
CF ₃ and O were supplied to the substrate as neutral particles.

The amount of CF ₃ supplied to the substrate was adjusted so that the F concentration in the film at that time was 4% by examining the FT-IR spectrum.

FIG. 10 shows the results of examining the moisture absorption of the formed F-added SiO ₂ film by leaving it in the air for one week.

From FIG. 10, it can be seen that no moisture absorption phenomenon was observed after standing in air regardless of the film forming temperature.
This result did not depend on the F concentration in the film.

FIG. 11 shows the relationship between the defect rate of Al wiring and the film forming temperature when F-added SiO ₂ is formed as the interlayer insulating film of the Al wiring shown in FIG. 2 by changing the film forming temperature. . FIG. 11 shows that when the film formation temperature becomes 500 ° C. or higher, A
It can be seen that the defect rate of the l wiring rapidly increases. From this result, when using the F-added SiO ₂ film as an interlayer insulating film between Al wirings, it is necessary to set the film formation temperature to 500 ° C. or lower.

The above results show that the ions are SiH ₃
⁺ At 20 eV, but is obtained by supplying CF ₃ and O on the substrate as neutral particles, Si _x H _y neutral particles or Si _x H _y ^{n +} ions are generated at the time of discharging the SiH ₄ (x ≧ 1, 0 ≦ y ≦ 2x + 2, n ≧ 1), neutral particles or ions containing at least O generated when O ₂ is discharged, and at least F generated when CF ₄ is discharged. When the neutral film or the ion containing such is supplied to form an insulating film mainly containing SiO ₂ containing F, at least one or a plurality of the ions are ions and the ion energy is 10 eV. Above, if the substrate temperature at the time of film formation was set to 500 ° C. or lower, an F-added SiO ₂ film which did not exhibit hygroscopicity similarly after being left in the air was obtained.

In this embodiment, SiH ₄ is used as a source gas for the ion source 21a and O _{2 is} used for the ion source 21b.
And the ion source 21c by introducing CF _4, but the particles generated in the discharge was used for film formation, the raw material gas is not limited to these gases, during discharge in the ion source 21 Si _x H _y neutral particles or Si _x H _y ^{n +} ions (x
≧ 1, 0 ≦ y ≦ 2x + 2, n ≧ 1), for example, inorganic silane gas such as SiH ₃ F, SiH ₂ F ₂ , Si ₂ H ₅ F, TEOS, HSi (OC
Similar effects were obtained by introducing an organic silane gas such as ₂ H ₅ ) ₃ .

In particular, as the raw material gas, 1 such as Si ₂ H ₆ is used.
It is generated when exciting the gas, such as Si atoms contains 2 or more in the molecule Si _x H _y neutral particles or Si _x
Case of forming using the H _y ^{n +} ions (x ≧ 2,0 ≦ y ≦ 2x + 2, n ≧ 1) formed of particles, Si _x H _y neutral particles or Si _x H _y ^{n +} ions (x = 1, 0 ≦ y ≦ 4, n ≧
1) When the film forming pressure, the film forming temperature, the number of particles supplied to the substrate and the like are the same as compared with the case where the film is formed using the particles of 2x and x
In the case of = 3, it improved about three times.

The same applies to the ion source 21b using a gas containing O such as N ₂ O or O ₃ as a gas for generating neutral particles or ions containing at least O during discharge. The effect was obtained.

Further, a gas containing F such as NF ₃ , ClF ₃ , or SiF ₄ may be used for the ion source 21 c as a gas for generating neutral particles or ions containing at least F during discharge. The effect was obtained.

(Second Embodiment) In the present embodiment, the same thin-film forming apparatus shown in FIG. 1 used in the first embodiment is used.

In the first embodiment, the ion sources 21a, 21b, and 21c are used as the ion sources for supplying particles to the substrate. However, in the present embodiment, the ion source 21d is further provided with an Ar source.
Was introduced, and Ar ⁺ ions and neutral particles of Ar were supplied to the substrate in the same manner as in the method shown in the first embodiment.

[0102] Further, in the ion source 21a introducing SiH _4, Si _x H _y neutral particles or Si _x H _y ^{n +} ions are generated at the time of discharging the _{SiH 4 (x ≧ 1,0 ≦ y} ≦ 2
x + 2, n ≧ 1), O ₂ is introduced into the ion source 21b, neutral particles or ions containing at least O generated when O ₂ is discharged, and CF ₄ is added to the ion source 21c. Then, neutral particles or ions containing at least F generated when CF ₄ was discharged were supplied to the substrate.

The relationship between the F concentration in the film and the relative dielectric constant of the film thus obtained, the relationship between the ion energy and the hygroscopic property after leaving for one week in the atmosphere, the F concentration in the film and the content after leaving for one week in the atmosphere. Relationship between moisture absorption, pressure during film formation and moisture absorption after leaving for one week in air, relationship between substrate temperature during film formation and moisture absorption after leaving for one week in air, substrate temperature during film formation There was no difference in the relationship with the conduction failure of the Al wiring from the result shown in the first embodiment.

FIG. 12 shows the relationship between the Ar ⁺ ion energy and the pore diameter x μm × depth 1 μm (x = 0.5, 0.75,.
0, 1.25, 1.5, 1.75, and 2.0 μm) are shown.

In the method shown in the first embodiment, SiH ₄
^When changing the energy of ⁺ ions and simultaneously supplying CF ₃ and O as neutral particles to the substrate to form a film,
The characteristics of embedding in the groove are also shown.

FIG. 12 shows that the Ar ⁺ ion was changed to 10 eV
It can be seen that the characteristics of embedding in the fine grooves are improved by supplying with the above energy.

The improvement in the characteristics of embedding in the fine grooves, which was improved by supplying Ar ⁺ ions at an energy of 10 eV or more, as shown in the present embodiment, is equivalent to the one-week air atmosphere shown in the first embodiment. It was confirmed under the conditions for forming the F-added SiO ₂ film that showed no moisture absorption after standing.

(Third Embodiment) FIG. 13 shows a third embodiment of the present invention.
It is a schematic diagram which shows the schematic structure of the thin film forming apparatus which concerns on Example.

This thin-film forming apparatus is similar to the thin-film forming apparatus shown in FIG.
8 is provided. The electrode 28 is connected to a high-frequency power supply 29, and the vacuum vessel 10 is provided with a pipe 30 for introducing a gas.

Hereinafter, a method for forming an F-added SiO ₂ film using this thin film forming apparatus will be described.

SiH ₄ is introduced into the ion source 21a, and S
Si _x H _y neutral particles or Si _x H _y ^{n +} ions are generated at the time of discharging the _{iH 4 (x ≧ 1,0 ≦ y} ≦ 2x +
2, n ≧ 1), O ₂ is introduced into the ion source 21b, and O ₂ is introduced.
Neutral particles or ions containing at least O generated when discharging ₂ are supplied to the ion source 21c with CF ₄
Was introduced, and neutral particles or ions containing at least F generated when CF ₄ was discharged were supplied to the substrate.

Further, at the same time, Ar gas
, And 500 W of 13.56 MHz high frequency power was applied to the high frequency power supply 29 to generate Ar plasma in the vacuum vessel 10.

The relationship between the F concentration in the film and the relative dielectric constant of the film thus obtained, the relationship between the ion energy and the hygroscopic property after standing in the air for one week, the concentration of F in the film and the concentration in the film after standing in the air for one week. Relationship between moisture absorption, pressure during film formation and moisture absorption after leaving for one week in air, relationship between substrate temperature during film formation and moisture absorption after leaving for one week in air, substrate temperature during film formation There was no difference in the relationship with the conduction failure of the Al wiring from the result shown in the first embodiment.

FIG. 14 shows the relationship between the Ar plasma density measured by the Langmuir probe method and the pore diameter x μm × depth 1 μm.
m (x = 0.5, 0.75, 1.0, 1.25, 1.
5, 1.75 and 2.0 μm).

At this time, the energy of SiH ₄ ⁺ ions was set to 10 eV, and CF ₃ and O as neutral particles were simultaneously supplied to the substrate to form a film.

In the method shown in the first embodiment, SiH ₄
^The characteristics of embedding in the grooves when the film is formed by simultaneously supplying CF ₃ and O as neutral particles to the substrate while setting the energy of ⁺ ions to 10 eV and also displaying the neutral particles are also shown. From this result, the Ar plasma density at the time of film formation was 1 × 10 ¹¹ cm ^−1.
By doing so, it was found that the characteristics of embedding in fine grooves were improved.

Note that the Ar film during film formation described in the present embodiment was used.
The improvement of the filling characteristics in the fine grooves, which was improved by increasing the plasma density to 1 × 10 ¹¹ cm ⁻¹ or more, was attributable to the fact that the F-added SiO, which showed no moisture absorption after being left in the air for one week as shown in the first embodiment, was used. It was confirmed under the conditions for forming _two films.

In this embodiment, the vacuum vessel 10
Ar discharge occurred in the ion source 21a.
H ₄ , CF ₄ in 21c, and pipe 30 in vacuum vessel 10
The substrate is exposed to discharge plasma by introducing more O ₂ , and furthermore, the Si _x H generated when SiH ₄ is discharged to the substrate.
_y neutral particles or Si _x H _y ^{n +} ions (x ≧ 1, 0 ≦
(y ≦ 2x + 2, n ≧ 1) Even when neutral particles or ions containing at least F generated when CF ₄ is discharged are supplied to the substrate, the same effect is obtained.

In the embodiment, the discharge in the reaction vessel 10 is performed by applying a high frequency to the electrode 29 provided on the side wall. However, the present invention is not limited to this method. For example, a microwave discharge or a magnetron discharge may be used. 1 × 10 ¹¹ cm ^-1
Similar effects were obtained with the above-described method of forming plasma.

In the first to third embodiments, microwave discharge is used for the discharge in the ion sources 21a, b, c, and d. However, the present invention is not limited to this method.
A high frequency power of 56 MHz may be used, and electron beam impact may be used. In addition, the same effect can be obtained by any method of discharging gas introduced into the ion source.

In the first to third embodiments, the ion source 21, the extraction electrode 22, and the focusing lenses 23 and 2 are used.
4. An ion beam line including a mass filter 25, a speed reducer 26, a neutralizing chamber 27, and a deflector 14 is provided to supply ions and neutral particles onto a substrate. Even if a plasma CVD apparatus using cyclotron resonance, an inductively coupled plasma CVD apparatus, a plasma CVD apparatus using a helicon wave, or the like, an F-added SiO ₂ film that does not show moisture absorption after being left in the air can be obtained.

(Fourth Embodiment) FIG. 15 shows a fourth embodiment of the present invention.
It is a schematic diagram which shows the schematic structure of the thin film forming apparatus which concerns on Example.

In FIG. 15, a reaction vessel 40 made of an insulating material has a substrate support 42 on which a substrate to be processed (substrate) 41 is mounted, and a nozzle for introducing a source gas into the reaction vessel 40. 46 is provided and the vacuum pump 4
At 5 evacuated. Reaction vessel 40 and vacuum pump 45
A pressure adjusting valve 50 for adjusting the pressure inside the reaction vessel 40 is provided between the two. The substrate support 42 is provided therein with a resistance heater 43 and a cooling pipe 44 for circulating a coolant.
9 is connected. A high-frequency coil 47 is wound around the side wall of the reaction vessel 40, and a high-frequency power supply 48 is further connected.

Next, an example in which an interlayer insulating film of a multilayer wiring is formed using this thin film forming apparatus will be described below with reference to FIG.

First, S on which an Al wiring is formed in advance
The i-substrate 41 is set on the substrate support 42 and the vacuum pump 4
Exhaust at 5.

Next, the substrate 41 is
Heat to 00 ° C. 20 sc of SiH ₄ as source gas
cm, O ₂ at a flow rate of 200 sccm and CF ₄ at a flow rate of 50 sccm through the gas nozzle 46 into the reaction vessel 40, and the pressure is set to 5 mTorr.

Next, 13.56M is applied to the high-frequency electrode coil 47.
1 kW of high frequency power of 1 Hz to discharge
A plasma having a plasma density of ¹¹ cm ^-3 or more is formed. At this time, 500 W of 13.56 MHz high frequency power is applied to the substrate support 42.

However, when the film is formed in this manner, the S film is formed due to an effect considered to be due to etching by ions containing at least F generated at the time of discharge.
No iO ₂ film deposition occurred.

The ion energy at this time is estimated to be about 100 eV by Langmuir probe measurement.

For this reason, the 13.56 MHz high frequency power applied to the high frequency electrode coil 47 is not always applied at 1 kW, but the high frequency power is applied for a certain time, and the high frequency power is not applied for the next certain time. By repeating this, it was confirmed that a film equivalent to the F-added SiO ₂ film having no moisture absorption was observed after being left in the air for one week as shown in the first example. The details will be described below.

FIG. 16A shows that the high-frequency power supply 48
The time chart when discharging is performed by turning on for 50 seconds and turning off for 50 μsec is shown.

Further, at this time, the generation of SiH _x ⁺ (x = 1 to 4), O _x ⁺ (x = 1, 2) and CF _x ⁺ (x
= 2,3) Figure 1 shows the result of measuring the time change of the number of ions.
This is shown in FIG.

As is clear from FIG. 16, the ions containing F disappear rapidly after the high-frequency power supply is turned off, but the SiH _x ⁺ (x = 1 to 4) ions and O
_{The x} ⁺ (x = 1, 2) ions are present until the high frequency power supply is turned on, although the number of existing ions is reduced.

For this reason, in a certain time zone, the influence of ions containing at least F is not observed, and mainly the SiH _x
⁺ (X = 1 to 4) ions, O _x ⁺ (x = 1, 2) ions, and film formation proceeds only by neutral particles containing at least F.

Therefore, the above-mentioned etching effect by ions containing at least F generated at the time of discharge is suppressed, and F which does not show any moisture absorption after being left in the air for one week shown in the first embodiment is added. It is considered that film formation equivalent to the SiO ₂ film can be performed.

In the present embodiment, SiH ₄ , O ₂ , and CF ₄ were introduced as source gases, and particles generated during discharge were used for film formation. However, the source gases were limited to these gases. does not mean is, Si _x H _y neutral particles during discharge or Si _x H _y ^{n +} ions (x ≧ 1,0 ≦ y ≦ 2x +
2, n ≧ 1) to generate a gas (eg, SiHF
₃ , an inorganic silane gas such as SiH ₂ F ₂ or Si ₂ H ₅ F or an organic silane gas such as TEOS or HSi (OC ₂ H ₅ ) ₃ ) and neutral particles containing at least O during discharge. A gas that generates ions (for example, a gas containing O such as N ₂ O or O ₃ ) and a gas that generates neutral particles or ions that contain at least F during discharge (for example, NF ₃ or ClF ₃ , A similar effect was obtained by using a gas containing F such as SiF ₄ ).

In this embodiment, the high-frequency power supply 4
Although the frequency of 13.56 MHz was used for 8, 49, the frequency is not limited to this. The high frequency power supply 48 may be arbitrarily selected as long as it can maintain discharge. Regarding 49, it is possible to arbitrarily select a frequency.

Further, a DC power supply may be used instead of the high-frequency power supply 49.

Further, the discharge used in the present results was performed by applying a high frequency to the high-frequency electrode coil 47, but is not limited to this method.
Regardless of whether a microwave is used as an excitation method or another method, the applied power is turned ON / OFF at a constant cycle.
By doing so, a similar effect can be obtained.

In this embodiment, the high-frequency power supply 4
The ON / OFF times of 8 were 25 μsec and 5 respectively.
Although it was set to 0 μsec, it is not limited to this value.
What is necessary is just to determine suitably according to a discharge method, the shape of a film-forming container, etc.

Further, in the present embodiment, the application of the high frequency power is controlled by the ON / OFF operation. However, the present invention is not limited to this method, and the power A and the power B (A>B> The applied power may be controlled by alternately applying 0), or the applied power may be controlled by AM-modulating a high frequency.

(Fifth Embodiment) In this embodiment, the same thin film forming apparatus (FIG. 15) used in the fourth embodiment is used. Hereinafter, an example in which an interlayer insulating film of a multilayer wiring is formed will be described with reference to FIG.

First, an S wiring on which an Al wiring is formed in advance
The i-substrate 41 is set on the substrate support 42 and the vacuum pump 4
Exhaust at 5.

Next, the substrate 41 is
Heat to 00 ° C. 20 sc of SiH ₄ as source gas
cm, O ₂ at a flow rate of 200 sccm and CF ₄ at a flow rate of 50 sccm through the gas nozzle 46 into the reaction vessel 40, and the pressure is set to 5 mTorr.

Next, 13.56M is applied to the high frequency electrode coil 47.
1 kW of high frequency power of 1 Hz to discharge
A plasma having a plasma density of ¹¹ cm ^-3 or more is formed. At this time, 500 W of 13.56 MHz high frequency power is applied to the substrate support 42.

However, when the film is formed in this manner, the S film is formed due to an effect considered to be due to etching by ions containing at least F generated at the time of discharge.
No iO ₂ film deposition occurred.

The ion energy at this time is estimated to be about 100 eV by Langmuir probe measurement.

For this purpose, the voltage applied to the substrate support 42 was
The high-frequency power of 3.56 MHz is not always applied at 500 W, but after applying the high-frequency power for a certain time, the cycle of not applying the high-frequency for the next certain time is repeated, thereby obtaining the 1st embodiment shown in the first embodiment. It was confirmed that a film equivalent to an F-added SiO ₂ film showing no absorption of moisture after standing in air for a week could be formed.

The details will be described below. High frequency power supply 49
Is turned on for 25 μsec and turned off for 25 μsec, and the obtained deposition shape is shown in FIG.

(1) When the high-frequency power supply 49 is off The energy of ions incident on the substrate 60 on which the Al wiring 16 is formed is reduced to about several tens eV, and the SiO ₂ film 62 containing F is formed ( FIG. 17 (a)).

(2) When the high frequency power supply 49 is ON As described in the fourth embodiment, a plurality of types of ions
It is incident on the substrate with energy of about 00 eV,
At this time, the deposition of the SiO film does not proceed due to the influence of the etching of particles containing at least F atoms. However, when the SiO ₂ film 62 is already deposited on the base on which the Al wiring 61 is formed, etching at the upper corner of the Al wiring 61 particularly proceeds. Therefore, the so-called overhang shape generated during the deposition of the SiO ₂ film 63 is improved (FIG. 17B).

By repeating this, the SiO ₂ film 64
In order to deposit the SiO ₂ film 65 (FIG. 17C)
(D)) It is possible to form a film equivalent to the F-added SiO ₂ film which can be deposited in a fine trench between wirings and shows no moisture absorption after being left in the air for one week as shown in the first embodiment. That was confirmed.

In this example, SiH ₄ , O ₂ , and CF ₄ were introduced as source gases, and particles generated during discharge were used for film formation. However, the source gases were limited to these gases. does not mean is, Si _x H _y neutral particles during discharge or Si _x H _y ^{n +} ions (x ≧ 1,0 ≦ y ≦ 2x +
2, a gas (eg, SiH) that produces n ≧ 1
Inorganic particles such as F ₃ , SiH ₂ F ₂ and Si ₂ H ₅ F and organic silane gases such as TEOS and HSi (OC ₂ H ₅ ) ₃ , and neutral particles containing at least O during discharge. Alternatively, a gas generating ions (for example, a gas containing O such as N ₂ O or O ₃ ) and a gas generating neutral particles or ions containing at least F during discharge (for example, NF ₃ or ClF ₃₎ , SiF ₄
A similar effect was obtained by using a gas containing F).

In this embodiment, the high-frequency power supply 4
Although the frequency of 13.56 MHz was used for 8, 49, the frequency is not limited to this. The high frequency power supply 48 may be arbitrarily selected as long as it can maintain discharge. Regarding 49, it is possible to arbitrarily select a frequency.

Further, a DC power supply may be used instead of the high-frequency power supply 49.

Further, the discharge used in the present results was performed by applying a high frequency to the high-frequency electrode coil 47, but is not limited to this method.
A microwave may be used as an excitation method, or another method may be used.

In this embodiment, the high-frequency power supply 4
Although the ON / OFF time of No. 9 was set to 25 μsec each, the present invention is not limited to this value, and may be appropriately determined depending on the discharge method, the shape of the film forming container, and the like.

Further, in this embodiment, the application of the high frequency power is controlled by the ON / OFF operation. However, the present invention is not limited to this method. The power A and the power B (A>B> 0) ) May be applied alternately to control the applied power, or the high frequency may be AM modulated to control the applied power.

(Sixth Embodiment) In this embodiment, the same apparatus as the thin film forming apparatus (FIG. 15) used in the fourth embodiment is used. Hereinafter, an example in which an interlayer insulating film of a multilayer wiring is formed will be described with reference to FIG.

First, the S on which the Al wiring is formed in advance
The i-substrate 41 is set on the substrate support 42 and the vacuum pump 4
Exhaust at 5.

Next, the substrate 41 is
Heat to 00 ° C. 20 sc of SiH ₄ as source gas
cm, O ₂ at a flow rate of 200 sccm and CF ₄ at a flow rate of 50 sccm through the gas nozzle 46 into the reaction vessel 40, and the pressure is set to 5 mTorr.

Next, the high frequency electrode coil 47 is set to 250 kHz.
Of 1 × 10 ¹¹ c
A plasma having a plasma density of m ^-3 or more is formed.

At this time, a high frequency power of 200 W is applied to the substrate support. However, when the film was formed in this manner, the deposition of the SiO ₂ film did not occur due to an effect considered to be due to etching by ions containing at least F generated at the time of discharge.

The energy of the ions at this time is estimated to be about 100 eV by Langmuir probe measurement.

For this purpose, the high-frequency power of 200 kHz applied to the high-frequency electrode coil 47 is not always applied at 1 kW. If the high-frequency power of 200 kHz is applied for a certain time, the high-frequency power of 13.56 MHz is applied for the next certain time. By repeating the cycle, it was confirmed that the film formation equivalent to that of the F-added SiO ₂ film showing no moisture absorption after one week of standing in the air as shown in the first example can be performed.

As an example, it is assumed that a cycle of applying a high frequency of 13.56 MHz for 25 μsec and then applying a high frequency of 200 kHz for 25 μsec is repeated.

At this time, the SiO ₂ film containing F becomes the fifth
The deposition proceeds in the same shape as shown in the embodiment. That is, (1) When 13.56 MHz is applied, the ions generated by the discharge are affected by the etching of particles containing F because the ion density, that is, the number of ions incident on the substrate is large but the energy is low. Instead, they are deposited in a shape as shown in FIG.

(2) When 200 kHz is applied: The energy of ions generated by the discharge is 13.45.
MHz, the ions are incident on the substrate with an energy of about 100 eV. At this time, due to the influence of the etching of particles containing at least F atoms, SiO 2 The deposition of the _two films does not proceed.

However, when the SiO ₂ film is already deposited on the base on which the Al wiring is formed, the etching at the upper corner of the Al wiring particularly proceeds. Therefore, FIG.
As shown in (b), the so-called overhang shape generated at the time of depositing the SiO ₂ film is improved.

Since deposition is performed while repeating this, FIG.
As shown in FIGS. 7 (c) and 7 (d), it is possible to deposit on the fine inter-wiring groove, and 1) shown in the first embodiment.
F-added SiO ₂ with no moisture absorption after standing in air for a week
It was confirmed that a film equivalent to the film could be formed.

In this example, SiH ₄ , O ₂ , and CF ₄ were introduced as source gases, and particles generated during discharge were used for film formation. However, the source gases were limited to these gases. does not mean is, Si _x H _y neutral particles during discharge or Si _x H _y ^{n +} ions (x ≧ 1,0 ≦ y ≦ 2x +
2, a gas (eg, SiH) that produces n ≧ 1
Inorganic particles such as F ₃ , SiH ₂ F ₂ and Si ₂ H ₅ F and organic silane gases such as TEOS and HSi (OC ₂ H ₅ ) ₃ , and neutral particles containing at least O during discharge. Alternatively, a gas generating ions (for example, a gas containing O such as N ₂ O or O ₃ ) and a gas generating neutral particles or ions containing at least F during discharge (for example, NF ₃ or ClF ₃₎ , SiF ₄
A similar effect was obtained by using a gas containing F).

In this embodiment, the high-frequency power supply 4
Although the frequency of 13.56 MHz was used for 9, it is not limited to this frequency, and it is also possible to appropriately control the energy of ions by arbitrarily selecting the frequency.

Further, a DC power supply may be used instead of the high-frequency power supply 49.

Further, the discharge used for the present results was 13.56 MHz and 20.
This was performed by alternately applying a high frequency of 0 kHz. However, the present invention is not limited to this frequency. The same effect can be obtained by alternately applying a high frequency having a frequency of 1 MHz or more and a high frequency having a frequency of less than 1 MHz. . However, it is more effective to use frequencies separated from each other by one or more digits.

In this embodiment, the high-frequency power supply 4
The frequency of 8 is applied at 25 μsec each, but is not limited to this value, and may be appropriately determined depending on the discharge method, the shape of the film forming container, and the like. Further, the applied power may be controlled by FM modulating a high frequency.

(Seventh Embodiment) In this embodiment, the same thin-film forming apparatus (FIG. 15) used in the fourth embodiment is used. Hereinafter, an example in which an interlayer insulating film of a multilayer wiring is formed will be described with reference to FIG.

First, the S on which the Al wiring is formed in advance
The i-substrate 41 is set on the substrate support 42 and the vacuum pump 4
After exhausting at step 5, the resistance heater 43 heats the substrate 41 to 300 ° C.

Next, 20 scc of SiH ₄ was used as a source gas.
m, O ₂ at a flow rate of 200 sccm and CF ₄ at a flow rate of 50 sccm are introduced into the reaction vessel 40 through the gas nozzle 46,
Set the pressure to 5 mTorr.

Next, 13.56M is applied to the high-frequency electrode coil 47.
1 kW of high frequency power of 1 Hz to discharge
A plasma having a plasma density of ¹¹ cm ^-3 or more is formed. At this time, 500 W of 13.56 MHz high frequency power is applied to the substrate support 42.

However, when the film is formed in this manner, the effect of etching is considered to be due to etching by ions containing at least F generated at the time of electric discharge.
No iO ₂ film deposition occurred.

The ion energy at this time is estimated to be about 100 eV by Langmuir probe measurement.

For this purpose, the C introduced into the reaction vessel 40
Varying the flow rate of F _4, After a certain time 10sccm introduced, by repeating the cycle of introducing time 50sccm with the following moisture absorption is not observed at all in 1 week after air left shown in the first embodiment F-added SiO It was confirmed that film formation equivalent to _two films could be performed.

At this time, the SiO ₂ film containing F becomes the fifth
The deposition proceeds in the same shape as shown in the embodiment. For example, when the amount of CF ₄ introduced is changed every 1 msec and introduced, (1) at the time of introducing 100 sccm of CF _{4 The} ions generated by the discharge enter the substrate, and at this time, ions containing at least F Since the abundance ratio is lower than the number of other ions, the particles are not affected by the etching of particles containing F, and are deposited in a shape as shown in FIG.

(2) Introducing 50 sccm of CF _{4 The} ions generated by the discharge are also incident on the substrate, but since the abundance ratio of ions containing at least F is large, particles of particles containing at least F atoms are not included. Due to the influence of the etching, the deposition of the SiO ₂ film does not proceed. However, when the SiO ₂ film is already deposited on the base on which the Al wiring is formed, etching at the upper corner of the Al wiring particularly proceeds. Therefore, as shown in FIG. 17B, the so-called overhang shape generated when depositing the SiO ₂ film is improved.

Since the SiO ₂ film is deposited while repeating this, as shown in FIGS. 17 (c) and 17 (d), it is possible to deposit in a fine inter-wiring groove, and in the first embodiment, It was confirmed that a film formation equivalent to that of the F-added SiO ₂ film showing no absorption of moisture after one week of standing in the air could be performed.

In this example, SiH ₄ , O ₂ , and CF ₄ were introduced as source gases, and particles generated during discharge were used for film formation. However, the source gases were limited to these gases. does not mean is, Si _x H _y neutral particles during discharge or Si _x H _y ^{n +} ions (x ≧ 1,0 ≦ y ≦ 2x +
2, a gas (eg, SiH) that produces n ≧ 1
An inorganic silane gas such as F ₃ , SiH ₂ F ₂ , or Si ₂ H ₅ F, or an organic silane gas such as TEOS or HSi (OC ₂ H ₅ ) ₃ ) and neutral particles containing at least O during discharge. A gas that generates ions (for example, a gas containing O such as N ₂ O or O ₃ ) and a gas that generates neutral particles or ions that contain at least F during discharge (for example, NF ₃ or ClF ₃ , A similar effect was obtained by using a gas containing F such as SiF ₄ ).

In this embodiment, the high-frequency power supply 4
A frequency of 13.56 MHz was used for 8 and 49,
The frequency is not limited to this frequency.
Can be arbitrarily selected as long as the discharge can be maintained, and the frequency of the high-frequency power supply 49 can be arbitrarily selected.

Further, a DC power supply may be used instead of the high-frequency power supply 49.

Further, the discharge used in the present results was performed by applying a high frequency to the high-frequency electrode coil 47. However, the present invention is not limited to this method. Alternatively, other methods may be used.

In the present embodiment, the introduction time of CF ₄ is set to every 1 msec. However, the present invention is not limited to this value, and may be determined as appropriate according to the discharge method, the shape of the film forming container, and the like. .

Further, in this embodiment, CF ₄ is
The control was performed by alternately introducing the flow rate A and the flow rate B (A> B ≧ 0). However, the present invention is not limited to this method.
The same effect can be obtained regardless of whether it is supplied in a sawtooth shape or in another wave shape as long as the supply amount can be periodically increased or decreased.

Further, the same effect can be obtained by changing the flow rate of the source gas containing at least Si without changing the flow rate of CF ₄ containing at least F without fixing the flow rate.

(Eighth Embodiment) In this embodiment, the same apparatus as the thin film forming apparatus (FIG. 15) used in the fourth embodiment is used. Hereinafter, an example in which an interlayer insulating film of a multilayer wiring is formed will be described with reference to FIG.

First, the S on which the Al wiring is formed in advance
The i-substrate 41 is set on the substrate support 42 and the vacuum pump 4
After exhausting at step 5, the resistance heater 43 heats the substrate 41 to 300 ° C.

Next, 20 scc of SiH ₄ was used as a source gas.
m, O ₂ at a flow rate of 200 sccm and CF ₄ at a flow rate of 50 sccm are introduced into the reaction vessel 40 through the gas nozzle 46,
Set the pressure to 0.5 mTorr.

Next, 13.56M is applied to the high frequency electrode coil 47.
1 kW of high frequency power of 1 Hz to discharge
A plasma having a plasma density of ¹¹ cm ^-3 or more is formed. At this time, the high frequency power 200 W
Is applied. However, when the film is formed in this way, the effect of etching due to ions containing at least F generated at the time of electric discharge is considered to cause
No iO ₂ film deposition occurred.

The energy of the ions at this time is estimated to be about 100 eV by Langmuir probe measurement.

For this purpose, a cycle in which a film is formed under a vacuum of 0.5 mTorr for a certain time using a pressure adjusting valve 50 and a film is formed under a vacuum of 50 mTorr for the next certain time is repeated. It was confirmed that the film formation equivalent to that of the F-added SiO ₂ film showing no absorption of moisture after one week of standing in the air as shown in Example 1 can be performed.
As an example, under a vacuum of 0.5 mTorr, 1 msec.
After forming the film c, then for 1 ms under a vacuum of 50 mTorr
It is assumed that a cycle of forming an ec film is repeated. At this time, the deposition of the SiO ₂ film containing F proceeds in the same shape as shown in the fifth embodiment. In other words, (1) In the case where the film is formed under a vacuum of 50 mTorr Since the ions generated by the discharge have low energy, they are not affected by the etching of the particles including F and have a shape as shown in FIG. Is deposited. (2) In the case of forming a film under a vacuum of 0.5 Torr A plurality of types of ions generated by the discharge enter the substrate with an energy of about 100 eV. At this time, etching of particles containing at least F atoms is performed. , The deposition of the SiO ₂ film does not proceed. However, SiO
_{When the two} films are deposited on the base on which the Al wiring is formed, the etching at the upper corner of the Al wiring particularly proceeds. Therefore, as shown in FIG. 17B, the so-called overhang shape generated when depositing the SiO ₂ film is improved.

Since the SiO ₂ film is deposited while repeating this, as shown in FIGS. 17 (c) and 17 (d), it is possible to deposit in a fine inter-wiring groove, and as shown in the first embodiment. No moisture absorption after one week in air
It was confirmed that a film equivalent to the additive SiO ₂ film could be formed.

In the present embodiment, SiH ₄ , O ₂ , and CF ₄ were introduced as source gases, and particles generated during discharge were used for film formation. However, the source gases were limited to these gases. does not mean is, Si _x H _y neutral particles during discharge or Si _x H _y ^{n +} ions (x ≧ 1,0 ≦ y ≦ 2x +
2, a gas (eg, SiH) that produces n ≧ 1
Inorganic particles such as F ₃ , SiH ₂ F ₂ and Si ₂ H ₅ F and organic silane gases such as TEOS and HSi (OC ₂ H ₅ ) ₃ , and neutral particles containing at least O during discharge. Alternatively, a gas generating ions (for example, a gas containing O such as N ₂ O or O ₃ ) and a gas generating neutral particles or ions containing at least F during discharge (for example, NF ₃ or ClF ₃₎ , SiF ₄
A similar effect was obtained by using a gas containing F).

In this embodiment, the high-frequency power supply 4
Although the frequency of 13.56 MHz was used for 8, 49, the frequency is not limited to this. The high frequency power supply 48 may be arbitrarily selected as long as it can maintain discharge. Regarding 49, it is possible to arbitrarily select a frequency.

Further, a DC power supply may be used in place of the high-frequency power supply 49.

Further, the discharge used in the present results was performed by applying a high frequency to the high-frequency electrode coil 47, but is not limited to this method.
A microwave may be used as an excitation method, or another method may be used.

In the eighth embodiment, the adjustment of the film formation pressure is performed every 1 msec. However, the adjustment is not limited to this value, and may be determined as appropriate depending on the discharge method, the shape of the film formation container, and the like. .

Further, in this embodiment, the film forming pressure is controlled by alternately changing the film forming pressure between 0.5 mTorr and 50 mTorr. However, the present invention is not limited to this pressure, and is not limited to 1 × 10 ⁻² Torr. Vacuum and 1 × 10
^{It is} only necessary that the degree of vacuum of ^-2 Torr or more can be realized alternately.

However, it is more effective to use a vacuum degree in which the frequencies are separated by one or more digits.

Further, in this embodiment, the control is performed by alternately realizing the degree of vacuum A and the degree of vacuum B (A> B ≧ 0). However, the present invention is not limited to this method. By operating the pressure adjusting valve 50, the degree of vacuum can be periodically increased or decreased regardless of whether the degree of vacuum is changed in a sine wave shape, a sawtooth shape, or another wave shape. A similar effect can be obtained with a pressure control method.

Further, even if the pressure was changed by adjusting the flow rate of the raw material gas without adjusting the degree of vacuum by the pressure adjusting valve 50, the same effect was obtained.

(Ninth Embodiment) FIG. 18 shows a ninth embodiment of the present invention.
It is a schematic diagram which shows the schematic structure of the thin film forming apparatus which concerns on Example.

In FIG. 18, a reaction vessel 70 made of an insulating material has a substrate support base 72 for mounting a substrate to be processed (substrate) 71 therein, and a raw material gas supplied to the reaction vessel 70.
A nozzle 76 for introducing the gas into the inside is provided, and the inside of the inside is evacuated by a vacuum pump 75.

Between the reaction vessel 70 and the vacuum pump 75,
A pressure adjusting valve 80 for adjusting the pressure inside the reaction vessel 70 is provided. The substrate support base 72 is provided with a cooling pipe 74 for circulating a coolant, and further connected to a high frequency power supply 79.

A high frequency coil 77 is provided on the side wall of the reaction vessel 70.
, And a high-frequency power supply 78 is connected. Further, a lamp heater 73 is provided above the reaction container 70, and the substrate 71 can be rapidly heated through the window 81.

Next, an example in which an interlayer insulating film of a multilayer wiring is formed by using this thin film forming apparatus will be described below with reference to FIG.

First, the S layer on which the Al wiring is formed in advance
The i-substrate 71 is placed on the substrate support 72 and the vacuum pump 7
Exhaust at 5.

Next, the substrate 71 is removed by the cooling pipe 74.
Cool to 100 ° C. 20 s of SiH ₄ as source gas
ccm, O ₂ at 200 sccm, CF ₄ at 50 sccm
And introduced into the reaction vessel 40 through the gas nozzle 46 at a flow rate of 0.5 mTorr.

13.56 MHz for the high frequency electrode coil 47
Of high-frequency power of 500 W is applied and discharged, and 1 × 10 ¹¹
A plasma having a plasma density of cm ^-3 or more is formed.

At this time, coil high-frequency power of 100 W is applied to the substrate support. However, when the film was formed in this manner, the deposition of the SiO ₂ film did not occur due to an effect considered to be due to etching by ions containing at least F generated at the time of discharge.

At this time, the energy of the ions is estimated to be about 50 eV by Langmuir probe measurement.

For this purpose, first, the substrate temperature is cooled to -100 ° C. by circulating a coolant through the cooling pipe 44, and the lamp heater 71 is turned on in a pulsed manner.
By repeating the cycle of instantaneously heating the surface of the substrate 71 to raise and lower the substrate surface temperature between 200 ° C. and −100 ° C. to form a film, the substrate was left in the air for one week as shown in the first embodiment. It was confirmed that a film equivalent to an F-added SiO ₂ film having no moisture absorption can be formed later.

As one example, the lamp heater 73 is shown in FIG.
As shown in FIG. 9A, a cycle of lighting / non-lighting was repeated every 10 msec to form a film. Here, as shown in FIG. 19B, the temperature of the substrate surface 71 is 200 ° C.
It rises and falls between 100 ° C. At this time, the deposition of the formed SiO ₂ film to which F is added proceeds in the same shape as shown in the fifth embodiment.

That is, when a film is formed using a gas containing F as a raw material, the deposition does not proceed when the effect of etching by the particles containing F is strong, but when the etching effect is weak. The film formation proceeds.

That is, when the film formation temperature is as high as about 200 ° C., the fluorocarbon film is not easily deposited on the base surface,
An F-added SiO ₂ film is deposited. Film formation temperature is -100 ° C
On the other hand, if it is low, a fluorocarbon film is easily deposited on the base surface, and the etching proceeds.

However, when the SiO ₂ film is already deposited on the base on which the Al wiring is formed, the etching at the upper corner of the Al wiring particularly proceeds.

Therefore, the so-called overhang shape generated at the time of depositing the SiO ₂ film is improved. Since F is deposited while repeating deposition / etching, it is possible to deposit in fine trenches between wirings, and to show no moisture absorption after leaving it in the air for one week as shown in the first embodiment.
It was confirmed that film formation equivalent to that of the iO ₂ film was performed.

In this embodiment, SiH ₄ , O ₂ , and CF ₄ were introduced as source gases, and particles generated during discharge were used for film formation. However, the source gases were limited to these gases. does not mean is, Si _x H _y neutral particles during discharge or Si _x H _y ^{n +} ions (x ≧ 1,0 ≦ y ≦ 2x +
2, n ≧ 1) to generate a gas (eg, SiHF
₃ , an inorganic silane gas such as SiH ₂ F ₂ or Si ₂ H ₅ F or an organic silane gas such as TEOS or HSi (OC ₂ H ₅ ) ₃ ) and neutral particles or ions containing at least O during discharge. (For example, N ₂ O or O
Gas containing O such as ₃ ) and a gas generating neutral particles or ions containing at least F during discharge (for example, a gas containing F such as NF ₃ , ClF ₃ , and SiF ₄ ). A similar effect was obtained.

In this embodiment, the high-frequency power source 7
Although the frequency of 13.56 MHz was used for 8,79, it is not limited to this frequency, and the high frequency power supply 78 may be arbitrarily selected as long as it can maintain the discharge. Regarding 79, the frequency can be arbitrarily selected.

Further, a DC power supply may be used instead of the high-frequency power supply 79.

Further, the discharge used in the present results was performed by applying a high frequency to the high-frequency electrode coil 47, but the present invention is not limited to this method. Alternatively, other methods may be used.

In this embodiment, the adjustment of the film formation temperature is performed every 10 msec. However, the adjustment is not limited to this value, and may be determined as appropriate depending on the discharge method, the shape of the film formation container, and the like.

Further, in this embodiment, the film formation temperature is controlled by alternately changing the film formation temperature between 200 ° C. and −100 ° C., but is not limited to this pressure. Film forming temperature below 0 ℃ and 0 ℃
It would be effective if the above film formation temperatures could be realized alternately.

Further, in this embodiment, the film forming temperature is changed in a pulse shape. However, the present invention is not limited to this method, and the film forming temperature may be changed in a sine wave shape or in a sawtooth shape. The same effect can be obtained by changing the film formation temperature periodically even if it is changed or changed to another wave shape.

Further, the same effect was obtained regardless of whether a lamp heater, a resistance heater, or another heating method was used as the current heating method.

In the fourth to ninth embodiments, 1 ×
As a method for forming a plasma having a plasma density of 10 ¹¹ cm ^-3 or more, a case where an electrode is wound around a reaction vessel and a so-called inductively coupled plasma in which a high frequency is applied thereto is mainly used has been described. However, the present invention is not limited to this method, and it is possible to use a magnetron discharge, a capacitively coupled plasma, a cyclotron resonance, an electron beam impact, and a helicon wave plasma. Similar results were obtained by using a method for forming plasma having a plasma density of 1 × 10 ¹¹ cm ⁻³ or more.

(Tenth Embodiment) FIG. 20 is a schematic diagram showing a schematic configuration of a plasma CVD apparatus according to a tenth embodiment of the present invention.

In FIG. 20, a reaction vessel 110 made of an insulating material is provided with a substrate support table 112 for mounting a substrate 111 therein and a nozzle 116 for introducing a source gas into the reaction vessel 110. Vacuum pump 115
Is evacuated. The substrate support base 112 is provided with a heater 113 and a cooling pipe 114 for circulating a coolant therein, and further connected to a high-frequency power supply 119.

A high-frequency coil 117 is wound around the side wall of the reaction vessel 110, and a high-frequency power supply 118 is connected to the coil 117.

FIG. 21 shows an example in which an interlayer insulating film of a multilayer wiring is formed using SiF ₄ and O ₂ gases as source gases.
This will be described with reference to the process sectional views shown in FIGS.

First, the Si substrate 110 is set on the support 114 and heated to 300 ° C. by the resistance heater 113.

Next, 20 scc of SiF ₄ was used as a source gas.
m and O ₂ were simultaneously introduced into the reaction vessel 110 through the gas nozzle 116 at a flow rate of 200 sccm, and the pressure was 5 mT
Set to orr.

Also, a high-frequency power of 13.56 MHz of 1 kW is applied to the electrode 118 to discharge at a plasma density of 1 × 10 ¹¹ cm ⁻³ or more. At this time, 500 W of 13.56 MHz high frequency power is applied to the substrate support 114.

Thus, as shown in FIG.
A 500 nm SiO ₂ film 122 is deposited on the i-substrate 121.

Next, as shown in FIG. 21 (b), a 400 nm Al film was formed by DC magnetron sputtering and patterned to a width of 500 nm × a height of 400 n.
An Al wiring 123 of m is formed.

Thereafter, the Si substrate 11 is formed in the same manner as described above.
1 is set on the support 114 and the resistance heater 11
3 by heating to 300 ° C., 20 sccm of SiF _4, O
₂ at the same time through the gas nozzle 116 into the reaction vessel 110 at a flow rate of 200 sccm, and the pressure was increased to 5 mTorr.
Set to.

Further, a 13.56 MHz high frequency power of 1 kW is applied to the electrode 118 to discharge at a plasma density of 1 × 10 ¹¹ cm ⁻³ or more. At this time, 500 W of 13.56 MHz high frequency power is applied to the substrate support 114.

Thus, as shown in FIG. 21C, an 800 nm thick SiO ₂ film 24 is formed on the entire surface.

The SiO ₂ film thus obtained was examined by infrared absorption spectrum (FT-IR).
In the vicinity of 1080 cm ^-1 , 810 cm ^-1 and 450 cm ^-1
A peak due to the Si—O bond was observed, and a peak due to the Si—F bond was observed near 940 cm ⁻¹ . From this result, it can be seen that the SiO ₂ film including the Si—F bond was formed.

FIG. 22 shows the energy of ions incident on the substrate 111 and the amount of F (Si) contained in the F-added SiO ₂ film.
-F / Si-O) is shown.

Here, the ion energy is the plasma potential V _P [V] determined by the Langmuir probe method.
If the potential difference V _P -V _DC and high frequency drop potential V _DC was applied using a high frequency power source 119 to the substrate support table 112 [V]
Asked.

The high frequency drop potential V _DC [V] was controlled by changing the intensity of the high frequency power applied to the substrate support 112. FIG. 23 shows the relationship between the high-frequency power applied to the substrate support 114 and the ion energy incident on the substrate 111.

[0249] Also, the F concentration in the film than the infrared absorption spectrum (FT-IR), the integrated intensity and the Si-O spectra showing the binding of the spectrum (940 cm around ^-1) showing the Si-F bond (1080 cm ^-1 (In the vicinity) and the integrated intensity. From this result, it was found that the F concentration in the film can be controlled by the magnitude of the ion energy.
FIG. 24 shows the relationship between the energy of ions incident on the substrate 111 and the relative dielectric constant of the formed F-added SiO ₂ film. From FIG. 24, it was found that the relative dielectric constant of the F-doped SiO ₂ film can be controlled by the magnitude of the ion energy.

It should be noted that F-added S
After the iO ₂ film 124 was formed, the impurities in the film were analyzed by SIMS.
It was found that F atoms were implanted into the Al wiring at the order of 10 ¹⁹ atoms / cm ³ .

When F atoms are contained in the Al wiring at 1 × 10 ¹⁹ atoms
When s / cm ³ or more is present, F atoms react with H ₂ O in the atmosphere to form HF and cause so-called corrosion that corrodes Al.

FIG. 25 shows the results of a study on the relationship between the energy of ions incident on the substrate 111 and the amount of F implanted into the underlying Al wiring 123. Here, the ion energy is the plasma potential V as described above.
_It was determined as a potential difference V _P -V _DC between _P [V] and the high-frequency drop potential V _DC [V] applied to the substrate support 12. The amount of F in the underlying Al wiring 123 was determined by SIMS.

From FIG. 25, it can be seen that when the energy of ions incident on the substrate is 100 eV or more, F atoms enter the underlying Al wiring at 1 × 10 ¹⁹ atoms / cm ³ or more. Therefore, in order to reduce the number of F atoms implanted into the underlying Al wiring to 1 × 10 ¹⁹ atoms / cm ³ or less, it is necessary to form a film while suppressing the ion energy to 100 eV or less.

The penetration of F into the Al wiring is suppressed, and
A method of forming the F-added SiO ₂ film to have a relative dielectric constant of not more than the SiO ₂ film (relative dielectric constant of 3.8 to 3.9) formed by the Si thermal oxidation method will be described.

[0255] Using SiF4, O ₂ gas as a source gas, an example of forming an interlayer insulating film of a multilayer wiring, 26
This will be described with reference to the process sectional views shown in FIGS.

First, the Si substrate 111 is set on the support 114 and heated to 300 ° C. by the resistance heater 113.

Next, 20 scc of SiF ₄ was used as a source gas.
m and O ₂ were simultaneously introduced into the reaction vessel 110 through the gas nozzle 116 at a flow rate of 200 sccm, and the pressure was increased to 5 mT.
Set to orr.

The electrode 118 has an R of 13.56 MHz.
F power of 1 kW is applied to discharge at a plasma density of 1 × 10 ¹¹ cm ⁻³ or more. At this time, 1
An RF bias of 500 W at 3.56 MHz (the ion energy at this time is 220 eV from FIG. 23) is applied.

In this way, as shown in FIG.
F-added SiO ₂ film 1 with a thickness of 500 nm on i-substrate 171
72 are deposited.

Next, as shown in FIG. 26B, a 400 nm-thick A was formed by DC magnetron sputtering.
1 film is formed and patterned to have a width of 500 nm and a height of 4
An Al wiring 173 of 00 nm is formed.

Thereafter, the Si substrate 111 is again placed on the support 1
4 and set to 300 ° C with the resistance heater 113
Heat to 20 sccm of SiF ₄ as a source gas,
O ₂ was simultaneously introduced into the reaction vessel 110 through the gas nozzle 116 at a flow rate of 200 sccm, and the pressure was increased to 5 mTorr.
Set to r.

Further, a 13.56 MHz high frequency power of 1 kW is applied to the electrode 118 to discharge at a plasma density of 1 × 10 ¹¹ cm ⁻³ or more. At this time, 1
The first power of 1 as 3.56 MHz high frequency power
00W (the energy of the ions at this time is 60 e
V).

Thus, as shown in FIG.
l on the Si substrate 171 on which the wiring 173 is formed.
A F-doped SiO ₂ film 174 nm is deposited.

Further, 1 is applied to the substrate support 114.
The high frequency power of 3.56 MHz is converted to the first power of 100
W from 500W to a second power (energy when the ion 220eV from FIG. 23) is applied by raising, as shown in FIG. 26 (d), 800 nm of F added SiO ₂
The film 175 is continuously deposited.

An F-added SiO ₂ film was formed by the above-described method, and the amount of F contained in the underlying Al wiring was quantified by SIMS analysis. 1 × 10 ¹⁷ at which is the detection limit of analysis
oms / cm ³ or less.

The relative permittivity of the obtained F-added SiO ₂ film was 3.5. In the SiO ₂ film 174 formed by lowering the ion energy, F is 1 × 10 ¹⁸ a in the film.
about toms / cm ³ .

In this embodiment, the F-added SiO
_Although SiF ₄ and O ₂ were used as source gases for the _two films,
The present invention is not limited to this combination, and may be a single gas or a mixed gas of a plurality of gases as long as the source gas contains at least Si, O, and F, and may be N ₂ or a rare gas (He, He, Ar, etc.), the same effect was obtained.

In this embodiment, the Al wiring 17
When the F-added SiO ₂ film is formed on
The high frequency power applied to 14 is first deposited as 100 W (ion energy 60 eV) as a first power,
Further, as the second power, 500 W (ion energy 22
Although the deposition was performed with the power increased to 0 ev), the present invention is not limited to this combination, and the same effect can be obtained as long as the first power is ion energy of 100 eV or less.

As the second electric power, as shown in FIG. 24, an electric power for giving ions an ion energy suitable for a desired relative dielectric constant may be arbitrarily selected.

Further, in this embodiment, the SiO ₂ film of 30 nm is deposited by the first power, but the present invention is not limited to this thickness, and the same effect can be obtained if the thickness is at least 5 nm. Was done.

Furthermore, in this embodiment, the film is formed by switching from the first high-frequency power to the second high-frequency power. However, the present invention is not limited to this method.
If the ion energy given by the high-frequency power applied to the substrate support 114 at the time of starting film formation on the substrate 3 is 100 eV or less, the addition of F having a desired relative dielectric constant from the high-frequency power at the start of film formation The same effect was obtained even when the power was continuously increased or increased stepwise up to the high-frequency power for providing the ion energy necessary for forming SiO ₂ .

In this embodiment, the temperature at the time of film formation is 200 ° C., but the temperature is not limited to 200 ° C., and may be any number as long as the melting point of Al is 660 ° C. or less. .

Further, in this embodiment, the step of forming a film with the first power (ion energy) and the step of forming a film with the second power (ion energy) were performed in the same reaction vessel. However, a step of forming a film with a first power (ion energy) and a step of forming a film with a second power (ion energy) in different reaction vessels provided with a mechanism capable of transporting in a vacuum atmosphere. Similar effects were obtained even when performed separately.

In this embodiment, the ion energy is the average value of the energy of various ions incident on the substrate to be processed during the film formation. The same effect was obtained by setting the energy value to 100 eV or less at the beginning of film formation.

(Eleventh Embodiment) As described in the tenth embodiment, the penetration of F into the inside of the Al wiring 163 is suppressed, and the relative dielectric constant of the formed F-added SiO ₂ film is reduced by Si thermal oxidation. SiO ₂ film (relative permittivity of 3.8 to 3.
9) A method for achieving the following is described below.

The plasma CVD apparatus used in this embodiment is as follows.
The same one used in the tenth example was used.
Hereinafter, description will be made with reference to FIG.

As source gas, SiH ₄ , SiF ₄ , O ₂
An example in which an interlayer insulating film of a multilayer wiring is formed by using a gas will be described with reference to process cross-sectional views shown in FIGS. First, the Si substrate 111 is set on the support base 114 and heated to 300 ° C. by the resistance heater 113.

As a source gas, SiH ₄ was set at 10 sccm,
SiF ₄ and O ₂ at a flow rate of 10 sccm and 200 sccm are simultaneously introduced into the reaction vessel 110 through the gas nozzle 116, and the pressure is set to 5 mTorr.

The electrode 118 has a 13.56 MHz R
F power of 1 kW is applied to discharge at a plasma density of 1 × 10 ¹¹ cm ⁻³ or more. At this time, 1
An RF bias of 500 W at 3.56 MHz is applied.

In this way, as shown in FIG.
F-added SiO ₂ film 1 with a thickness of 500 nm on i-substrate 181
82 is deposited.

Next, as shown in FIG. 27B, a 400 nm-thick A was formed by DC magnetron sputtering.
1 film is formed and patterned to a width of 500 nm and a height of 4
An Al wiring 183 of 00 nm is formed.

Thereafter, the Si substrate 111 is again placed on the support 1
14 and the resistance heater 113
Heat to ° C. 20 scc of SiH ₄ as source gas
m and O ₂ were simultaneously introduced into the reaction vessel 110 through the gas nozzle 116 at a flow rate of 200 sccm, and the pressure was increased to 5 mT.
Set to orr.

Also, 13.56 MHz high frequency power of 1 kW is applied to the electrode 118 to discharge at a plasma density of 1 × 10 ¹¹ cm ⁻³ or more. At this time, 1
10 W is applied as high frequency power of 3.56 MHz.

In this way, as shown in FIG.
l on the Si substrate 181 on which the wiring 183 is formed,
A 0 nm SiO ₂ film 184 is deposited.

Further, SiF ₄ was added as a raw material gas,
The flow rate of SiF ₄ was reduced to 20 sccm each, and FIG.
As shown in FIG. 7 (d), an F-added SiO having a thickness of 800 nm
_Two films 185 are continuously deposited.

An F-added SiO ₂ film was formed by the above-described method, and the amount of F contained in the underlying Al wiring was quantified by SIMS analysis. As a result, no F was detected, and F in the Al wiring was determined by SIMS analysis. 1 × 10 ¹⁷ atoms, which is the detection limit
It turned out that it can be suppressed to s / cm ³ or less.

The relative dielectric constant of the obtained F-added SiO ₂ film was 3.6. However, the SiO ₂ film 174 formed using a gas containing no F as a raw material gas is affected by the jig in the reaction vessel 110 and F remaining on the side wall surface of the vessel, so that 1 × 10 ¹⁷ cm ^{Contains about -3} F. This is considered to be due to the influence of the F-containing gas during film formation and the influence of the F-containing gas used as the cleaning gas in the vacuum chamber.

In this embodiment, the F-added SiO
_{2 As} a raw material gas for the film, first use SiF ₄ and O ₂ ,
Further, SiH ₄ , SiF ₄ and O ₂ were used, but the present invention is not limited to this combination. First, a gas containing at least Si and O as a raw material gas and further containing a gas containing Si, O and F may be a plurality of mixed gases in if it alone of the gas used, also, N ₂ or noble gas (H
e, Ar, etc.), the same effect was obtained.

In this embodiment, first, the SiH
₄ 10 sccm, and film formation of O ₂ at a flow rate of 200 sccm, further 10scc the flow rates of SiH ₄ and SiF ₄
m and O ₂ were formed at a flow rate of 200 sccm, and the high-frequency power applied to the substrate support 114 was set to 500 W. However, the film is not limited to this value, and a desired relative dielectric constant, that is, a desired Even if the gas flow ratio and the high-frequency power applied to the substrate support 114 were selected according to the amount of F, the same effect was obtained.

Further, in the present embodiment, first, the film is formed by using the source gas containing no F, and further, the film is formed by using the source gas containing F. However, the present invention is not limited to this method. When film formation is started on the wiring 183, first, a raw material gas containing no F or the amount of F in the raw material gas is reduced by the amount of F necessary for forming F-added SiO ₂ having a desired relative dielectric constant. By preventing the amount of F from entering the underlying Al wiring, the amount of F in the source gas is continuously increased to the amount necessary to form F-added SiO ₂ having a desired relative dielectric constant. The same effect was obtained regardless of whether it was raised stepwise or stepwise.

Further, in this embodiment, the temperature at the time of film formation is 200 ° C., but the temperature is not limited to 200 ° C., and may be any number as long as it is not higher than 660 ° C. which is the melting point of Al. .

Further, in the present embodiment, a step of forming a film at a flow rate of a gas containing a desired F or less,
The step of forming a film at a flow rate of a gas containing is performed in the same reaction vessel, but is performed by a first power (ion energy) in a different reaction vessel provided with a mechanism capable of transporting in a vacuum atmosphere. The same effect was obtained even if the step of forming a film and the step of forming a film with the second power (ion energy) were performed separately.

[0293]

As described in detail above, the present invention (Claims 1 to 5)
According to claim _{6), Si x H y (} x ≧ 1,0 ≦ y ≦ 2
x + 2), using an oxygen material containing oxygen and a fluorine material containing fluorine, and at least one of these three materials is an ion having an ion energy of 10 eV or more, so that insulation having excellent dielectric constant and hygroscopicity is obtained. A film can be formed.

Further, as described in detail above, according to the present invention (claim 7), in an atmosphere having a degree of vacuum of 1 × 10 ⁻² Torr or less and a plasma density of 1 × 10 ¹¹ cm ⁻³ or more, By forming the film while increasing the ion energy of ions used for forming the insulating film, an insulating film containing fluorine and having a low dielectric constant containing SiO ₂ as a main component can be formed while suppressing damage to the base. become.

Further, as described in detail above, according to the present invention (claim 8), in an atmosphere having a degree of vacuum of 1 × 10 ⁻² Torr or less and a plasma density of 1 × 10 ¹¹ cm ⁻³ or more, By forming the film while increasing the flow rate of the fluorine raw material containing fluorine, while containing the fluorine while suppressing damage to the base,
An insulating film having SiO ₂ as a main component and having a low dielectric constant can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a thin film forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a step of the method for forming a multilayer wiring according to the first embodiment of the present invention;

FIG. 3 is a characteristic diagram showing a relationship between a wave number and an absorbance, and an infrared absorption spectrum diagram.

FIG. 4 is a characteristic diagram showing a relationship between CF ₃ neutral particles and F concentration in a film.

FIG. 5 is a characteristic diagram showing the relationship between the F concentration in the film and the relative dielectric constant.

FIG. 6 is a characteristic diagram showing the relationship between the energy of SiH _x ⁺ ions and the amount of moisture absorbed after leaving in air for one week.

FIG. 7 is a characteristic diagram showing the relationship between the energy of SiH _x ⁺ ions and the amount of moisture absorbed after leaving in air for one week.

FIG. 8 is a characteristic diagram showing the relationship between the F concentration in the film and the amount of moisture absorbed after leaving in air for one week.

FIG. 9 is a characteristic diagram showing a relationship between a pressure at the time of film formation and an amount of moisture absorption after being left in the air for one week.

FIG. 10 is a characteristic diagram showing a relationship between a film forming temperature and a moisture absorption amount after leaving in the air for one week.

FIG. 11 is a characteristic diagram showing a relationship between a film formation temperature and a conduction failure rate of an Al wiring formed on a base.

FIG. 12 is a characteristic diagram showing a relationship between Ar ⁺ ion energy and aperture diameter.

FIG. 13 is a schematic diagram showing a schematic configuration of a thin film forming apparatus according to a third embodiment of the present invention.

FIG. 14 is a characteristic diagram showing a relationship between plasma density and aperture diameter.

FIG. 15 is a schematic diagram showing a schematic configuration of a thin film forming apparatus according to a fourth embodiment of the present invention.

FIG. 16 is a time chart showing a temporal change in the density of ions present in plasma.

FIG. 17 is a process sectional view showing a method of forming an insulating film according to a fourth embodiment of the present invention.

FIG. 18 is a schematic view showing a schematic configuration of a thin film forming apparatus according to a ninth embodiment of the present invention.

FIG. 19 is a time chart showing a time change of a substrate temperature.

FIG. 20 is a schematic view showing a schematic configuration of a thin film forming apparatus according to a tenth embodiment of the present invention.

FIG. 21 is a process sectional view showing a method of forming a semiconductor device according to a tenth embodiment of the present invention.

FIG. 22 is a characteristic diagram showing a relationship between ion energy and F concentration in a film.

FIG. 23 is a characteristic diagram showing a relationship between high-frequency power (bias voltage) and ion energy.

FIG. 24 is a characteristic diagram showing a relationship between ion energy and relative permittivity.

FIG. 25 is a characteristic diagram showing a relationship between ion energy and F concentration in underlying Al wiring.

FIG. 26 is a process sectional view showing the method of forming the semiconductor device according to the eleventh embodiment of the present invention.

FIG. 27 is a process sectional view showing a method of forming a semiconductor device according to a twelfth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Reaction container 11 ... Substrate to be processed (substrate) 12 ... Substrate support 13 ... Heater 14a-14c ... Deflector 15 ... Cooling pipe 20 ... Gas supply system container 21a-21d ... Ion source 22a-22d ... Extraction electrode 23a-23d ... focusing lenses 24a to 24d ... focusing lenses 25a to 25d ... mass filters 26a to 26d ... decelerators 27a to 27d ... neutralization chamber 28 ... high frequency power application coil 29 ... high frequency power supply 30 ... Ar gas introduction pipe 31 ... Si Substrate 32 SiO ₂ film including F 33 Al wiring 34 SiO ₂ film including F 35 Al wiring 36 SiO ₂ film including F 40 Reaction vessel 41 Substrate to be processed (substrate) 42 Substrate support 43: Resistance heater 44: Cooling pipe 45: Vacuum pump 46: Source gas introduction nozzle 47: High frequency electrode coil 48: RF power supply 49 ... high frequency power supply 50 ... pressure adjusting valve 60 ... SiO ₂ film 61 ... Al wiring 62 to 65 ... SiO ₂ film 70 ... reactor 71 ... substrate to be processed comprising F (substrate) 72 ... substrate support 73 ... Lamp heater 74 Cooling pipe 75 Vacuum pump 76 Source gas introduction nozzle 77 High frequency electrode coil 78 High frequency power supply 79 High frequency power supply 80 Pressure regulating valve 81 Window 110 Reaction vessel 111 Substrate to be processed (substrate) 112 ... Substrate support stand 113 ... Heaters 114a-14c ... Cooling pipe 115 ... Vacuum pump 116 ... Raw material gas nozzle 117 ... High frequency application electrode 118 ... High frequency power supply 119 ... High frequency power supply 121 ... Si substrate 122 ... SiO ₂ film including F 123 ... Al wiring 124: SiO ₂ film containing F 171: Si substrate 172: SiO ₂ film containing F 173: Al wiring 174: SiO ₂ film formed with reduced ion energy 175: SiO ₂ film containing F 181: Si substrate 182: SiO ₂ film containing F 183: Al wiring 184: Flow rate of F-containing gas is reduced SiO ₂ film 185 ... SiO ₂ film containing F

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-302593 (JP, A) JP-A-7-307293 (JP, A) JP-A-3-111578 (JP, A) JP-A-7-307 74245 (JP, A) JP-A-2-77127 (JP, A) JP-A-6-333919 (JP, A) JP-A-6-507942 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) H01L 21/316 H01L 21/31

Claims (8)

(57) [Claims] To 1. A treated substrate, wherein the fluorine, in forming an insulating film composed mainly of SiO _2, as a material of the insulating _{film, Si x H y (x ≧} 1,0 ≦ y
.Ltoreq.2x + 2), a method for manufacturing a semiconductor device, wherein an oxygen source containing oxygen and a fluorine source containing fluorine are used, and at least one of the three sources is an ion having an ion energy of 10 eV or more. . 2. When forming an insulating film containing fluorine and SiO ₂ as a main component on a substrate to be processed, supplying argon ions to the substrate to be processed.
As a material of the insulating _{film, Si x H y (x ≧} 1,0 ≦ y
.Ltoreq.2x + 2), a method for manufacturing a semiconductor device, wherein an oxygen source containing oxygen and a fluorine source containing fluorine are used, and at least one of the three sources is an ion having an ion energy of 10 eV or more. . 3. The method according to claim 1, wherein the insulating film is formed at a degree of vacuum of 1 × 10 ^−2.
3. The method of manufacturing a semiconductor device according to claim 1, wherein the method is performed in an atmosphere having a pressure of not more than Torr and a plasma density of not less than 1 × 10 ¹¹ cm ⁻³ . Wherein said Si _x H _y method of manufacturing a semiconductor device according to claim 1 or claim 2, characterized in that the x ≧ 2. 5. The fluorine source is an ion containing fluorine,
And a method of manufacturing a semiconductor device according to claim 1 or claim 2, wherein said Si _x H _y the mass is greater than. 6. The semiconductor device according to claim 1, wherein at least two of said three raw materials are excited, and a method of exciting at least one raw material is different from that of the other raw materials. Manufacturing method. 7. An insulating film containing fluorine and mainly composed of SiO ₂ is formed on a substrate to be processed in an atmosphere having a degree of vacuum of 1 × 10 ⁻² Torr or less and a plasma density of 1 × 10 ¹¹ or more. In doing so, a method of manufacturing a semiconductor device, comprising supplying ions to be used for forming the insulating film to the substrate to be processed while increasing ion energy. 8. An insulating film containing fluorine and containing SiO ₂ as a main component is formed on a substrate to be processed in an atmosphere having a degree of vacuum of 1 × 10 ⁻² Torr or less and a plasma density of 1 × 10 ¹¹ or more. In doing so, while increasing the flow rate of the fluorine material containing fluorine,
A method for manufacturing a semiconductor device, comprising supplying the semiconductor device to the substrate to be processed.