JP2001196365A - Method and device for film formation and producing method for semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film forming device, with which an insulating film having a low dielectric constant and improved in moisture resistance can be formed. SOLUTION: This device has a chamber 1 capable of pressure reduction, a film forming gas feeding means 101B, which is connected with the chamber 1, equipped with the feeding source of a silicon-containing gas, the feeding source of a boron-containing gas, the feeding source of a nitrogen-containing gas having N-O bonding and the feeding source of an oxygen gas, means 2, 3, 7 and 8 for making the film forming gas, which is led into the chamber 1, into plasma and a means 3 for holding a substrate 21 to form the film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming method, a film forming apparatus, and a method for manufacturing a semiconductor device, and more particularly, to a film forming method for forming a boron-containing silicon oxide film, a film forming apparatus, and a method for manufacturing a semiconductor device. About the method.

[0002]

2. Description of the Related Art In recent years, high integration of semiconductor integrated circuit devices has been promoted.
Higher data transfer rates are required along with higher densities. For this reason, the wiring material is changed from the conventionally used aluminum (Al) to copper (C) having a lower resistivity.
u). As an interlayer insulating film, an attempt is made to adopt an FSG film (fluorine-containing silicon oxide film) having a lower dielectric constant and an SOG film (Spin-On Glass film) having a lower dielectric constant instead of the conventional CVD-SiO ₂ film. ing.

[0003]

However, there is a problem that the SOG film having a low dielectric constant has poor adhesion. Further, in the FSG film having a low dielectric constant, which has been studied in the past, the lower limit of the relative dielectric constant was about 3.5. However, the lower the dielectric constant, the higher the fluorine content. Absorption occurs. For this reason, there is a problem that the relative dielectric constant increases.

For this reason, it is conceivable that the upper and lower portions of the FSG film are sandwiched between NSG films (silicon oxide films containing no impurities or the like), but the relative dielectric constant of the entire multilayer is significantly increased due to the NSG film. And the effect of the low dielectric constant disappears. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the related art, and has a low dielectric constant and a film forming method and a film forming apparatus capable of forming an insulating film with improved moisture resistance. And a method for manufacturing a semiconductor device.

[0005]

According to a first aspect of the present invention, there is provided a film forming apparatus comprising: a chamber capable of reducing pressure; a silicon-containing gas supply source and a boron-containing gas supply source; A film-forming gas supply means connected to the chamber, comprising: a nitrogen-containing gas supply source having an N—O bond; and an oxygen gas supply source, and plasma-forming the film-forming gas introduced into the chamber. And a means for holding a substrate on which the film is to be formed. The invention according to claim 2 relates to the film forming apparatus according to claim 1, wherein the means for converting the film forming gas into plasma is 4. The invention according to claim 3, further comprising a parallel plate type first and second electrode, wherein the second electrode also serves as a means for holding the substrate on which the film is to be formed. Item 3. The first and second parallel plate type devices according to Item 2, Out of electrodes, the first power supply means is connected to the first electrode, the second to the second electrode
Wherein the frequency of the power supplied from the first power supply means is higher than the frequency of the power supplied from the second power supply means,
According to a fourth aspect of the present invention, there is provided the film forming apparatus according to the first aspect, wherein the means for converting the film forming gas into a plasma includes an ECR (El
(ectron cyclotron resonance) method, wherein the invention according to claim 5 relates to the film forming apparatus according to claim 1, wherein the means for converting the film forming gas into plasma is a high frequency power. It is characterized by having an antenna for radiating helicon and generating helicon plasma.

The invention according to claim 6 relates to a film forming method,
A step of plasma-forming and reacting a film-forming gas containing a silicon-containing gas, a boron-containing gas, a nitrogen-containing gas having an N—O bond, and oxygen gas, and a chemical gas using the plasma-formed film-forming gas. Forming a boron-containing silicon oxide film on the film formation substrate by phase growth. The invention according to claim 7 relates to a film formation method, and uses the film formation apparatus according to claim 3. And applying a power to the first and second electrodes to convert a film-forming gas containing a silicon-containing gas, a boron-containing gas, a nitrogen-containing gas having an N—O bond, and an oxygen gas into a plasma to cause a reaction. And a step of forming a boron-containing silicon oxide film on the deposition target substrate by chemical vapor deposition using the plasma-formed deposition gas.
8. The film forming method according to claim 6, wherein the ratio of the oxygen gas to the nitrogen-containing gas having the NO bond is 1
The present invention according to a ninth aspect relates to the film forming method according to the sixth or seventh aspect, wherein the film forming gas includes the silicon-containing gas and the boron-containing gas. The invention according to claim 10, wherein the gas contains at least one of Ar, He, and H _{2 in} addition to the gas, the nitrogen-containing gas having an N—O bond, and the oxygen gas. 8. The method according to claim 6, wherein the silicon-containing gas is at least one of SiH _{4 and} Si (OC ₂ H ₅ ) _4.
The invention according to claim 1 relates to the film forming method according to claim 6 or 7, wherein the boron-containing gas is B ₂ H ₆ or B (OSi (CH
_{3) 3),} characterized in that any one of the _three, according to claim 1
The invention according to claim 2 relates to the film forming method according to claim 6 or 7, wherein the boron-containing gas comprises B (OSi (CH ₃ ) ₃ ) ₃ and B
(13) The film forming method according to claim 13 or 14, wherein the mixed gas is a mixed gas with (OR) ₃ (R = C _n H _{2n + 1} (n = 1 or 2)). It relates to, the nitrogen-containing gas with NO bond is characterized by a any one of NO or NO _2, the invention of claim 14, wherein the claim 6
16. The invention according to claim 15, further comprising, after the step of forming the boron-containing silicon oxide film, exposing the boron-containing silicon oxide film to plasma of oxygen gas. The method according to claim 14, further comprising, after exposing the boron-containing silicon oxide film to oxygen gas plasma, exposing the boron-containing silicon oxide film to ammonia gas plasma. I have.

According to a sixteenth aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the step of forming the boron-containing silicon oxide film by the film forming method according to any one of the sixth to fifteenth aspects. 18. The method according to claim 17, further comprising the step of forming a silicon oxide film having good moisture resistance or a boron-containing silicon oxide film on the silicon oxide film containing boron. Forming a recess or an opening in the boron-containing silicon oxide film after the step of forming the boron-containing silicon oxide film by the film forming method according to any one of claims 15 to 15; and forming copper in the recess or the opening. And a step of embedding a layer. The invention according to claim 18 relates to a method for manufacturing a semiconductor device, wherein the substrate is formed by the film forming method according to any one of claims 6 to 15. Forming a down-containing silicon oxide film is characterized by alternately perform the steps of forming a wiring layer on the boron-containing silicon oxide film.

The operation of the present invention will be described below. According to the film forming apparatus of the present invention, it is provided with a silicon-containing gas supply source, a boron-containing gas supply source, and a nitrogen-containing gas supply source having an N—O bond, and further includes a plasma generation unit that converts the film formation gas into plasma. It has. Incidentally, a boron-containing silicon oxide film (BSG film (Borosilicate glass) in which boron is contained in the silicon oxide film.
Although the relative permittivity of the film decreases) and the relative permittivity decreases in inverse proportion to the B content, the moisture resistance decreases as the B content increases. On the other hand, when nitrogen is included in the boron-containing silicon oxide film to be formed, the moisture resistance can be improved. In particular, by using a nitrogen-containing gas having an N—O bond, a BSG film, which is a kind of oxide film, can be formed with O, and N during film formation can be kept to a small amount. If N ₂ gas is simply used, a large amount of N is contained in the film, and the dielectric constant becomes higher than necessary.

In the film forming apparatus of the present invention, a boron-containing silicon oxide film containing nitrogen can be formed by the plasma CVD method with the above configuration. As a result, a BSG film having a low dielectric constant and good moisture resistance can be formed. As plasma generation means, for example, means for generating plasma using first and second electrodes of a parallel plate type, means for generating plasma by ECR (Electron Cyclotron Resonance) method, and helicon plasma by radiation of high frequency power from an antenna Can be used.

[0010] Among these plasma generating means, a power source for supplying electric power of two high and low frequencies to the parallel plate type first and second electrodes, for example, a frequency of 13.56 MHz.
Power supply for supplying high frequency power of 400 kHz
By connecting a power supply for supplying the AC power, the power of these two frequencies can be applied to each electrode to generate plasma.

As a result, Si having a large binding energy in the formed BSG film due to its plasma potential.
A larger amount of -O bonds and BO bonds can be included, and unstable bonds such as Si-OH can be reduced. For this reason, a low dielectric constant of the BSG film can be achieved. In the film forming method of the present invention, plasma CVD using a film forming gas containing a silicon-containing gas, a boron-containing gas, and a nitrogen-containing gas having an N—O bond
The BSG film is formed by the method.

In the present invention, the film-forming gas contains a boron-containing gas and a nitrogen-containing gas having an N—O bond.
As a result, a BSG film, which is a kind of oxide film, can be formed, and N during film formation can be kept small. A BSG film having a low dielectric constant and high moisture resistance can be formed. If N ₂ gas is simply used, a large amount of N is contained in the film, and the dielectric constant becomes higher than necessary. Furthermore, since the BO bond of the BSG film has a higher binding energy than the Si-F bond of the FSG film, an interlayer insulating film having higher moisture resistance can be obtained.

Further, by including O _{2 in the} film forming gas, B can be taken into the network structure of Si—O in the BSG film. That is, many Si-OB bonds can be generated. Thus, a BSG film having a low dielectric constant and good moisture resistance can be formed. Further, by including O _{2 in the} deposition gas, the BSG film can be changed from a Si-rich state to a stoichiometric state. Therefore, a BSG film having a lower dielectric constant can be formed.

Further, by using trimethylsilyl borate (B (OSi (CH ₃ ) ₃ ) ₃ ) ₃ as a boron supply source in the film-forming gas, B contained in the Si—O network structure in the BSG film can be formed. Since the ratio increases, a BSG film having a low dielectric constant and good moisture resistance can be formed.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a side view showing a configuration of a film forming apparatus 101 according to a first embodiment of the present invention.

The film forming apparatus 101 uses a plasma gas to deposit a boron-containing silicon oxide film (BS) on a film forming substrate 21.
It comprises a film forming unit 101A where a G film is formed, and a film forming gas supply unit 101B having a plurality of gas supply sources constituting the film forming gas. The film forming unit 101A
As shown in FIG. 1, a chamber 1 that can be depressurized is provided. The chamber 1 is connected to an exhaust device 6 through an exhaust pipe 4. An on-off valve 5 for controlling conduction / non-conduction between the chamber 1 and the exhaust device 6 is provided in the exhaust pipe 4. The chamber 1 is provided with pressure measuring means such as a vacuum gauge (not shown) for monitoring the pressure in the chamber 1.

The chamber 1 is provided with a pair of opposing upper electrodes (first electrodes) 2 and lower electrodes (second electrodes) 3, and supplies high frequency power of 13.56 MHz to the upper electrodes 2. An RF power supply 7 is connected, and an AC power supply 8 for supplying AC power of a frequency of 400 kHz to the lower electrode 3 is connected. Electric power is supplied from these power sources 7 and 8 to the upper electrode 2 and the lower electrode 3 to turn the film forming gas into plasma. The upper electrode 2, the lower electrode 3, and the power supplies 7 and 8 constitute a plasma generating means for converting the film forming gas into plasma.

The upper electrode 2 also serves as a device for dispersing the film forming gas. A plurality of through-holes are formed in the upper electrode 2, and the opening of the through-hole on the surface facing the lower electrode 3 serves as a discharge port (introduction port) for the deposition gas. The discharge port for the film forming gas or the like is connected to the film forming gas supply unit 101B via a pipe 9a. The lower electrode 3 also serves as a holder for the substrate 21 on which the film is to be formed, and includes a heater (not shown) for heating the substrate 21 on the holder.

In the film forming gas supply unit 101B, monosilane (SiH ₄ ), diborane (B ₂ H ₆ ), argon (A
r), a source of dinitrogen monoxide (N ₂ O), oxygen (O ₂ ), nitrogen trifluoride (NF ₃ ), and nitrogen (N ₂ ). These gases are appropriately supplied to the branch pipes 9b to 9h and the pipe 9 to which all the branch pipes 9b to 9h are connected.
a is supplied into the chamber 1 of the film forming unit 101A. In the middle of the branch pipes 9b to 9h, the flow control means 11a
11g and opening / closing means 10b to 10p for controlling conduction / non-conduction of the branch pipes 9b to 9h,
An opening / closing means 10a for closing / conducting the pipe 9a is provided in the middle of the process. Among the above gases, NF ₃ is a gas for purifying the inside of the pipe 9 a, the branch pipes 9 b to 9 h and the chamber 1 by a chemical reaction, and N ₂ is a gas for cleaning the inside of the pipe 9 a and the branch pipes 9 b to 9 h. And a gas for purging the residual gas in the chamber 1.

According to the film forming apparatus 101 described above, a silicon-containing gas supply source, a boron-containing gas supply source,
A nitrogen-containing gas supply source having an -O bond, and plasma generating means 2, 3, for converting the film forming gas into plasma.
7 and 8 are provided. Therefore, a BSG film containing nitrogen can be formed by the plasma CVD method. Thereby, as shown in the third embodiment below, a BSG film having a low dielectric constant and good moisture resistance can be formed.

As plasma generation means, for example, means for generating plasma using parallel plate type first and second electrodes 2 and 3, ECR (Electron Cyclotron Resonan)
Means for generating plasma by the ce) method, means for generating helicon plasma by radiating high frequency power from an antenna, and the like. Among these plasma generating means, power supplies 7 and 8 for supplying electric power of two frequencies, high and low, are connected to the first and second electrodes 2 and 3 of the parallel plate type. Therefore, it is possible to generate the plasma by applying the power of these two frequencies to the electrodes 2 and 3 respectively.

Thus, the BSG film formed by the film forming apparatus 101 can contain more Si-O bonds and BO bonds having a large binding energy due to its plasma potential. Unstable bonds can be reduced. For this reason, a low dielectric constant of the BSG film can be achieved. In addition, by including O _{2 in the} film forming gas, B can be taken into the Si—O network structure in the BSG film formed by the film forming apparatus 101. That is, many Si-OB bonds can be generated. Therefore, the dielectric constant of the BSG film can be reduced, and the moisture resistance of the BSG film can be improved.

Further, by including O _{2 in the} film forming gas, the BSG film formed by the film forming apparatus 101 can be changed from a Si-rich state to a stoichiometric state.
For this reason, a low dielectric constant of the BSG film can be achieved. (Second Embodiment) FIG. 2 is a side view showing a configuration of a film forming apparatus 102 according to a second embodiment of the present invention.

The difference from the film forming apparatus 101 of the first embodiment is that the supply source of the film forming gas of the film forming apparatus 101 further includes trimethylsilyl borate (B (OSi (C
H ₃ ) ₃ ) ₃ ). B (OSi
(CH ₃ ) ₃ ) ₃ 13 is a liquid, and B (OSi (CH ₃ ) ₃ ) ₃ can be contained in He and supplied by bubbling He.

He (B) in B (OSi (CH ₃ ) ₃ ) ₃ 13
A pipe 9k for supplying water is inserted, and a pipe 9j for purging branches off from the pipe 9k. Purge pipe 9j
Is connected to the branch pipe 9i so that residual gas in the branch pipe 9i and the pipe 9a and in the chamber 1 can be purged. Opening / closing means 10w and 10x are installed in the pipes 9j and 9k, respectively.

Further, a heater (not shown) is attached to the branch pipe 9i and the pipe 9a through which B (OSi (CH ₃ ) ₃ ) ₃ passes, and the branch pipe 9i and the pipe 9a are branched by preventing the temperature thereof from lowering. B (O) is placed on the inner wall of the pipe 9i and the pipe 9a.
Si (CH ₃ ) ₃ ) ₃ is prevented from adhering. The new branch pipe 9i is provided with a flow rate adjusting means 11h and opening / closing means 10u and 10v.

Further, the film forming apparatus 101 of the first embodiment
A source of TMB (trimethyl borate (B (OCH ₃ ) ₃ )) in place of the source of B ₂ H ₆ in
A He source is used instead of the He source. In this case, since B (OSi (CH ₃ ) ₃ ) ₃ 13 has a fixed content ratio of Si, B and O, it is difficult to adjust the B content in the insulating film to be formed. The content of TMB is added so that the B content during the film formation can be arbitrarily adjusted. The reason why TMB containing oxygen is used instead of B ₂ H ₆ is as follows. That is, TMB is a liquid source, and the source gas is also a fluid. Since these flow into the same pipe, they heat the pipe. In this case, the liquid source does not decompose even when heated to about 80 ° C., but B ₂ H
_This is because TMB, which is a liquid source, is better because (gas) is easily decomposed and the film becomes cloudy.

The film forming apparatus 102 of this embodiment has the same effects as the film forming apparatus 101 of the first embodiment, and further, as shown in the following fourth embodiment,
A BSG film having a low dielectric constant can be formed similarly to the film forming apparatus 101 of the first embodiment. Particularly, in this embodiment, since trimethylsilyl borate (B (OSi (CH ₃ ) ₃ ) ₃ ) is used as a film forming gas, Si—O in the BSG film formed by the film forming apparatus 102 is used. Of the B contained in the network structure of (1) increases, which results in BSG having a low dielectric constant and excellent moisture resistance.
A membrane can be obtained.

In the first and second embodiments, the parallel plate electrodes 2 and 3 are provided in the film forming unit 101A as plasma generating means.
A supply source of microwave power of a frequency of 2.45 GHz, a waveguide that carries the supplied power, an ECR (Electron Cyc
A magnetic field generating means or the like for applying energy by a lotron resonance method may be provided. Alternatively, a high-frequency power supply source having a frequency of 13.56 MHz, an antenna for radiating high-frequency power for converting the supplied film forming gas into plasma, and a generated helicon plasma are provided upstream of the film forming unit 101A. Magnetic field generating means for generating a magnetic field that guides the magnetic field to the film forming unit 101A may be provided. (Third Embodiment) Next, a method of forming a film on a film formation substrate 21 according to a third embodiment using the above-described film forming apparatus 101 will be described.

First, a substrate 21 having an insulating film, a wiring layer and the like formed on a semiconductor substrate is loaded into a chamber 1 of a film forming apparatus 101 shown in FIG. Is formed on the lower electrode 3 of FIG. Then
The inside of the chamber 1 is evacuated and decompressed. In addition, the deposition target substrate 2
The substrate 1 is heated to maintain the temperature of the substrate 21 at 400 ° C.

Subsequently, SiH _{4 at} a flow rate of 30 sccm,
B ₂ H ₆ diluted to a volume concentration of about 1% with Ar, and a flow rate of 6
A deposition gas consisting of 00 sccm N ₂ O and a flow rate of 120 sccm O ₂ is introduced into the chamber 1 and the gas pressure in the chamber 1 is set to 0.8 Torr. In this case, the flow rate ratio of B ₂ H ₆ / SiH _{4 in} the film-forming gas was set in order to test the change in the relative dielectric constant with respect to the boron content in the formed BSG film and the change in the relative dielectric constant due to moisture absorption. 0, 10, 3
Various film formations having different boron contents in the silicon oxide film are performed by changing the values to 0, 50, 60, 70, and 80%.

Next, a frequency of 13.56 M is applied to the upper electrode 2.
Hz high-frequency power of 50 W is applied, and AC power 400 W of a frequency of 400 kHz is applied to the lower electrode 3. Thus, the film forming gas in the chamber 1 is turned into plasma. While maintaining this state, the BSG film 22 is formed on the deposition target substrate 21. In this case, the nitrogen content during film formation is about 6.5 wt%. The nitrogen content during film formation is preferably 10 wt% in view of the balance between the dielectric constant and the moisture resistance.

FIG. 3 shows the BSG thus formed.
₆ is a graph showing how the relative permittivity of the film changes with respect to the flow ratio of each gas represented by B ₂ H ₆ / SiH ₄ for the film 22. In FIG. 3, the vertical axis indicates the relative dielectric constant expressed on a linear scale, and the horizontal axis indicates B ₂ H ₆ / SiH _{4 on} a linear scale.
Is shown. The relative permittivity is a value at a frequency of 1 MHz.

As shown in FIG. 3, the boron content in the BSG film 22 varies depending on the value of the flow ratio of B ₂ H ₆ / SiH ₄ , and the relative dielectric constant monotonically increases as the flow ratio increases. Decrease. FIG. 5 shows the results of investigating the infrared absorption intensity of the BSG film formed under the condition of B ₂ H ₆ / SiH ₄ = 0.5. In FIG. 5, the vertical axis indicates the absorption intensity (arbitrary unit), and the horizontal axis indicates the wave number (cm ⁻¹ ) expressed on a linear scale.

As shown in FIG. 5, even when left in the air for one month, the wave number characteristics of the absorption intensity hardly changed. In other words, it indicates that the BSG film 22 of this embodiment has a low moisture absorption and a high moisture resistance. Then
A process of forming a copper wiring when the BSG film 22 is applied to an interlayer insulating film in a damascene process will be described.

As shown in FIG. 7B, an opening 23 is formed in the BSG film 22 formed in the step shown in FIG. 7A. Subsequently, a tantalum nitride film (TaN film) 24 by the CVD method and a copper film (Cu film) by the sputtering method
25 are sequentially formed. Next, a copper film (C
Then, a Cu film 26 is embedded in the opening 23.

Next, as shown in FIG.
Cu film 2 by (Chemical Mechanical Polishing) method
6, 25 and the TaN film 24 are sequentially polished and removed to flatten the surface, and a wiring made of the Cu film 26a is formed in the opening 23 using the TaN film 24a and the Cu film 25a as underlying conductive layers. If necessary, an interlayer insulating film made of the BSG film according to the present invention may be subsequently formed, and a copper wiring may be further formed to form a multilayer wiring structure.

As described above, according to the third embodiment of the present invention, a plasma CVD method using a film forming gas containing a silicon-containing gas, a boron-containing gas, and a nitrogen-containing gas having an N—O bond is used. A BSG film is formed. Since the deposition gas contains a boron-containing gas and a nitrogen-containing gas having an N—O bond, a BSG film containing nitrogen can be formed. As a result, the BSG film has a low dielectric constant and high moisture resistance.

Further, the BO bond of the BSG film is FSG
Since the bonding energy is larger than that of the Si—F bond of the film, the moisture resistance of the interlayer insulating film can be further improved. In addition, since plasma is generated by applying power at two frequencies, high and low, a large amount of Si—O bonds or B—O bonds having high binding energy can be included in the film due to the plasma potential. Unstable bonds such as -OH can be reduced. This can be for the following reasons. That is, since low-frequency (400 kHz) power is applied to the deposition target substrate 21 side, decomposition products of the source are violently beaten by the bombardment effect. At this time, the one having a weak bond is easily decomposed, but the one having a strong bond remains without being decomposed. However, even in the above case, a high frequency (13.56 MHz)
Is applied, and the decomposition of gas is promoted more than the electric power of the low frequency. However, by reducing the electric power of the high frequency, the decomposition can be suppressed. In the embodiment, since the low-frequency power is applied under the condition that the high-frequency power is reduced to about 50 W, only the weak coupling is decomposed, and a lot of the strong coupling originally remains. is there.

As a result, it is possible to improve the moisture resistance of the film formation and suppress the change of the relative dielectric constant with time due to moisture absorption.
Further, by including O _{2 in the} deposition gas, B can be incorporated into the network structure of Si—O in the BSG film. That is, since a large number of Si—OB bonds can be generated, the moisture resistance of the insulating film can be further improved while achieving a low dielectric constant of the insulating film. Furthermore, since the BSG film can be changed from a Si-rich state to a stoichiometric state by containing O _{2 in the} film forming gas, it is possible to further lower the dielectric constant of the BSG film. it can.

In addition, Ar, He, H ₂ are used as the above-mentioned film forming gas.
Can be added. In this case, the distribution of the film thickness in the film formation substrate 21 can be improved. In the above description, the flow rate of O ₂ is set to 12 with respect to the flow rate of N ₂ O of 600 sccm.
0 sccm, but the flow ratio of O ₂ / N ₂ O is 1/1.
0 to 1/5 is preferred. For example, N ₂ O flow rate 600
The flow rate of O ₂ is set to 60 to 120 sccm with respect to sccm. The flow rate of O ₂ was focused on this range, the flow rate of O ₂ is increased, the more OH in the film formation (water) is, moisture resistance deteriorates, and because the dielectric constant becomes high.

Further, the gas pressure in the chamber 1 at the time of film formation is set to 0.8 Torr, but is preferably set to 1 Torr or less. Thereby, cloudiness of film formation can be suppressed. The term "white turbidity" means that the reaction of the gas becomes violent and a gas phase reaction occurs, and the resulting film is not transparent but becomes a white turbid film. (Fourth Embodiment) Next, a method of manufacturing a semiconductor device according to a fourth embodiment using the film forming apparatus 102 will be described.

First, a substrate 21 on which an insulating film, a wiring layer and the like are formed on a semiconductor substrate is carried into the chamber 1 of the film forming apparatus 102 shown in FIG. The deposition target substrate 21 is set on the lower electrode 3 among the lower electrodes 3. Next, the inside of the chamber 1 is evacuated and decompressed.
Further, the film formation substrate 21 is heated, and the temperature of the film formation substrate 21 is kept at 400 ° C.

Subsequently, trimethylsilyl borate (B
(OSi (CH_Three)_Three)_Three) Is heated to 75 ° C and bubbled with He
To run. SiH with a flow rate of 50 sccm_FourAnd the flow rate 50s
ccm of He and 1000 sccm of N_TwoO and O_Two
Is introduced into the chamber 1 and the chamber
The gas pressure in 1 is set to 0.8 Torr. In this case, O
_TwoOf the relative dielectric constant with respect to the flow rate of
nδ) to test the change_TwoFlow rate of 20
0, 400, 600, 800 and 1000 sccm and seeds
Change each time.

Next, a frequency of 13.56 M was applied to the upper electrode 2.
Hz high-frequency power of 50 W is applied, and AC power 400 W of a frequency of 400 kHz is applied to the lower electrode 3. Thereby, the film forming gas in the chamber 1 is turned into plasma. While maintaining this state, the BSG film 22 is formed on the deposition target substrate 21. In this case, the nitrogen content during the film formation is slightly lower than that of the silane-based film of the third embodiment, that is, about 4.6 wt%.

Subsequently, a CMP stopper film 27 made of a silicon carbide film (SiC film) or a silicon carbide oxide film (SiOC film) is formed on the entire surface. FIG. 4 shows how the relative permittivity changes with respect to the flow rate of O ₂ and how the dielectric loss (tan δ) changes. The vertical axis on the left side of FIG. 4 shows the relative permittivity expressed on a linear scale, the vertical axis on the right side shows the dielectric loss expressed on a linear scale, and the horizontal axis shows the flow rate of O ₂ (sccm) expressed on a linear scale. Show. The relative permittivity is a value at a frequency of 1 MHz.

According to FIG. 4, the flow rate of O ₂ although higher dielectric constant small decreases, the dielectric constant with respect to changes in the flow rate of O ₂ does not vary too greatly. Further, the dielectric loss does not change so much with the change in the flow rate of O ₂ , similarly to the relative dielectric constant. The flow rate of O ₂ is 100 flow rates of N ₂ O.
It is desirable to set 300 to 500 sccm for 0 sccm. This is because, when it is in this range, the dielectric constant is relatively small and the moisture resistance is high.

Next, a process of forming a copper wiring by applying the BSG film 22 to an interlayer insulating film in a damascene process will be described. As shown in FIG. 8B, the BSG film 22
And an opening 23 is formed in the CMP stopper film 27. Subsequently, a tantalum nitride film (TaN
Film) 28 and a copper film (Cu film) 29 by sputtering.

Next, a copper film (Cu film) 30 is formed by plating.
Is formed, and the Cu film 30 is embedded in the opening 23. Next, as shown in FIG. 8C, the Cu films 30 and 29 and the TaN film 28 are polished and removed by CMP to flatten the surface, and the TaN film 28a and the Cu film 2 are formed in the opening 23.
An interconnect made of a Cu film 30a having a base conductive layer 9a is formed. Although the CMP stopper film 27 is slightly removed by CMP, it functions as a CMP stopper.

If necessary, an interlayer insulating film made of the BSG film according to the present invention is formed subsequently, and further wirings are formed to form a multilayer wiring structure of three or more layers. As described above, according to the fourth embodiment of the present invention, in addition to having the same effects as the third embodiment, in particular, trimethylsilyl borate (B (OSi (C
Since H ₃ ) ₃ ) ₃ ) is used, Si—
Because the proportion of B contained in the network structure of O increases,
The BSG film 22 having a low dielectric constant and excellent moisture resistance can be obtained.

In the fourth embodiment, if necessary, trimethyl borate (T
MB) or triethyl borate (TEB: B (OC
₂ H ₅ ) ₃ ) may be added. Thereby, the boron content in the BSG film can be arbitrarily adjusted. (Fifth Embodiment) Next, a method of manufacturing a semiconductor device according to a fifth embodiment will be described with reference to FIG.

First, a lower wiring layer 33 made of an aluminum film, a high melting point metal film or the like is formed on the insulating film 31. Subsequently, an interlayer insulating film 32 made of a BSG film is formed by covering the lower wiring layer 33 by the film forming method according to the third or fourth embodiment. Next, the interlayer insulating film 32 on the lower wiring layer 33
After the opening 34 is formed, the opening 34 is filled to form an upper wiring layer 35 made of an aluminum film, a high melting point metal film, or the like. Thereby, a two-layer multilayer wiring structure can be created.

Thereafter, if necessary, a multilayer wiring structure having three or more layers can be formed by the same method. As described above, according to the fifth embodiment, similarly to the third and fourth embodiments, a BSG film containing nitrogen can be formed, and therefore, has a low dielectric constant and good moisture resistance. Interlayer insulating film 3
2 can be obtained.

Although the present invention has been described in detail with reference to the embodiments, the scope of the present invention is not limited to the examples specifically shown in the above embodiments, and a range not departing from the gist of the present invention. Modifications of the above embodiment are included in the scope of the present invention. For example, in FIG. 7B and FIG.
After forming the openings 23 and 34 in the SG films 22 and 32 and before forming the conductive layers 24, 25, 26 or 35, FIG.
As shown in FIGS. 0 and 12, insulating films 41a and 42a having good moisture resistance may be formed as a whole covering the openings 23 and 34.
As the insulating films 41 a and 42 a having good moisture resistance, for example, an NSG film formed by a plasma CVD method using a film forming gas obtained by removing a boron-containing gas from the above film forming gas corresponds. Alternatively, a BSG film having a low boron content (preferably 1 wt% or less) formed by a plasma CVD method by reducing the flow rate of the boron-containing gas in the above film formation gas corresponds to the above.

Before and after the formation of the BSG film 22 or 32, the insulating films 41a, 41b or 42a, 42b having good moisture resistance are formed as shown in FIGS.
The G film 22 or 32 is formed of insulating films 41a and 41b having good moisture resistance.
Alternatively, they may be sandwiched between 42a and 42b. Thereby, the moisture resistance of the entire interlayer insulating film including the BSG film 22 or 32 can be further improved. The insulating films 42a and 42b having good moisture resistance are also the insulating films 41a and 41b having good moisture resistance.
It can be formed similarly to 41b.

In the third to fifth embodiments, no processing is performed after the BSG films 22 and 32 are formed.
The openings 23 and 34 are formed, and the underlying conductive layers 24 and 2 are further formed.
5 or 28, 29 and wirings 26, 30, 32 are formed. However, after forming the BSG films 22 and 32 and before forming the openings 23 and 34 or before forming the underlying conductive layers 24, 25 or 28 and 29 and the wirings 26, 30 and 35, By exposing the films 22, 32 to plasma of oxygen gas, the moisture resistance of the BSG films 22, 32 can be improved. After the oxygen plasma treatment, the BSG films 22 and 32 can be further exposed to the plasma of ammonia gas to further improve the moisture resistance of the BSG films 22 and 32.

[0057]

As described above, according to the present invention, plasma CVD using a film-forming gas containing a silicon-containing gas, a boron-containing gas, and a nitrogen-containing gas having an N--O bond.
A boron-containing silicon oxide film (BSG film) is formed by a method. For this reason, nitrogen can be contained in the formed BSG film, so that the moisture resistance of the BSG film can be improved while achieving a low dielectric constant of the BSG film. Furthermore, since the BO bond has a larger binding energy than the Si-F bond, the moisture resistance of the interlayer insulating film can be further improved.

Further, since the film-forming gas contains O ₂ , a large amount of Si—O—B bonds can be generated in the BSG film, so that the moisture resistance of the BSG film can be improved. Further, by including O _{2 in the} film forming gas, B
Since the SG film can be changed from a Si-rich state to a stoichiometric state, a lower dielectric constant of the BSG film can be achieved.

Further, by using trimethylsilyl borate (B (OSi (CH ₃ ) ₃ ) ₃ ) as a film forming gas,
Since the proportion of B contained in the Si-O network structure of the BSG film increases, an insulating film having a low dielectric constant and excellent moisture resistance can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration of a film forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a side view illustrating a configuration of a film forming apparatus according to a second embodiment of the present invention.

FIG. 3 is a graph showing a relationship between a relative dielectric constant and a boron content of a boron-containing silicon oxide film formed using the film forming apparatus according to the first embodiment.

FIG. 4 is a graph showing the relationship between the relative dielectric constant and the oxygen flow rate of a boron-containing silicon oxide film formed using the film forming apparatus according to the second embodiment.

FIG. 5 is a graph showing the change over time in the composition of a boron-containing silicon oxide film formed using the film forming apparatus according to the first embodiment, which was examined by infrared absorption intensity.

FIG. 6 is a graph showing the change over time in the composition of a boron-containing silicon oxide film formed using the film forming apparatus according to the second embodiment, which was investigated by infrared absorption intensity.

FIG. 7 is a cross-sectional view showing a method of applying the boron-containing silicon oxide film of this embodiment to an interlayer insulating film of a copper wiring.

FIG. 8 is a cross-sectional view showing another method of applying the boron-containing silicon oxide film of this embodiment to an interlayer insulating film of a copper wiring.

FIG. 9 is a sectional view showing a method of applying the boron-containing silicon oxide film of this embodiment to an interlayer insulating film of a two-layer wiring.

FIG. 10 is a cross-sectional view showing another method for applying the boron-containing silicon oxide film of this embodiment to an interlayer insulating film of a copper wiring.

FIG. 11 is a cross-sectional view showing another method for applying the boron-containing silicon oxide film of this embodiment to an interlayer insulating film of a copper wiring.

FIG. 12 is a cross-sectional view showing another method of applying the boron-containing silicon oxide film of this embodiment to an interlayer insulating film of a two-layer wiring.

FIG. 13 is a cross-sectional view showing another method of applying the boron-containing silicon oxide film of this embodiment to an interlayer insulating film of a two-layer wiring.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Chamber 2 Upper electrode (1st electrode) 3 Lower electrode (2nd electrode) 4 Exhaust pipe 5 Open / close valve 6 Exhaust device 7 High frequency power supply power supply 8 AC power supply power supply 9a Pipe 9b-9h Branch pipe 10a-10w Open / close Means 11a to 11g Flow rate adjusting means 21 Deposition substrate 22 BSG film 23, 34 Opening 24, 24a, 28, 28a Tantalum nitride film (TaN film) (underlying conductive layer) 25, 25a, 29, 29a Copper film ( Cu film) (underlying conductive layer) 26, 26a, 30, 30a Copper film (Cu film) 27, 27a CMP stopper film 31 Insulating film 32 Interlayer insulating film 33 Lower wiring layer 35 Upper wiring layer 101, 102 Film forming apparatus 101A 102A Film formation unit 101B, 102B Film formation gas supply unit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuhiro Maekawa 2-1844-2 Kozoji-cho, Kasugai-shi, Aichi Prefecture Inside Fujitsu VSI Co., Ltd. (72) Takuya Sakai 2-844-2 Kozoji-cho, Kasugai-shi, Aichi Fujitsu Inside Viel S.I. Co., Ltd. (72) Inventor Yoshimi Shioya 2-13-29 Konan, Minato-ku, Tokyo Inside Semiconductor Process Research Laboratories Co., Ltd. (72) Inventor Kazuo Maeda 2-13-29 Konan, Minato-ku Tokyo F-term in semiconductor process laboratory (reference) 4K030 AA06 AA11 AA13 AA18 FA01 FA02 KA14 KA30 5F045 AA08 AA10 AB36 AC01 AC07 AC11 AC12 AC15 AC16 AC17 AC19 AD08 AE19 BB16 CB05 DC63 DP03 DQ10 EE12 EH02 BAH07 BC BF09 BF23 BF32 BG02 BH16

Claims (18)

[Claims] A chamber capable of reducing pressure, a supply source of a silicon-containing gas, a supply source of a boron-containing gas, a supply source of a nitrogen-containing gas having an N—O bond, and a supply source of an oxygen gas. A film formation gas supply means connected to the chamber, a means for converting the film formation gas introduced into the chamber into plasma, and a means for holding a film formation substrate. 2. The means for converting the film-forming gas into plasma,
2. The film forming apparatus according to claim 1, further comprising a parallel plate type first and second electrode, wherein the second electrode also serves as a means for holding the substrate on which the film is to be formed. 3. A first power supply means is connected to the first electrode and a second power supply means is connected to the second electrode among the first and second electrodes of the parallel plate type. And
3. The film forming apparatus according to claim 2, wherein the frequency of the power supplied from the first power supply unit is higher than the frequency of the power supplied from the second power supply unit. 4. The means for converting the film forming gas into a plasma,
2. The film forming apparatus according to claim 1, wherein said means is a means for generating plasma by an ECR (Electron Cyclotron Resonance) method. 5. The means for converting the film forming gas into a plasma,
2. The film forming apparatus according to claim 1, further comprising an antenna for radiating high-frequency power, and a means for generating helicon plasma. 6. A plasma-forming reaction of a film forming gas containing a silicon-containing gas, a boron-containing gas, a nitrogen-containing gas having an N—O bond, and an oxygen gas; Forming a boron-containing silicon oxide film on the substrate on which the film is to be formed by chemical vapor deposition using the method. 7. A silicon-containing gas, a boron-containing gas, and a nitrogen-containing gas having an N—O bond by applying electric power to the first and second electrodes using the film forming apparatus according to claim 3. Forming a boron-containing silicon oxide film on a substrate to be formed by chemical vapor deposition using the plasma-formed film-forming gas, and reacting the film-forming gas containing oxygen gas into plasma. A film forming method comprising: 8. The film forming method according to claim 6, wherein a ratio of the oxygen gas to the nitrogen-containing gas having the NO bond is in a range of 1/10 to 1/5. 9. The film-forming gas may be Ar, He, or H in addition to the silicon-containing gas, the boron-containing gas, the nitrogen-containing gas having an NO bond, and the oxygen gas.
8. The film forming method according to claim 6, wherein at least one of the _two is included. 10. The film forming method according to claim 6, wherein the silicon-containing gas is at least one of SiH _{4 and} Si (OC ₂ H ₅ ) ₄ . 11. The boron-containing gas may be B ₂ H ₆ or B ₂
8. The film forming method according to claim 6, which is any one of (OSi (CH ₃ ) ₃ ) ₃ . 12. The boron-containing gas is B (OSi (C
_8. The film forming method according to claim 6, wherein the mixed gas is H ₃ ) ₃ ) ₃ and B (OR) ₃ (R = C _n H _{2n + 1} (n = 1 or 2)). . 13. The film forming method according to claim 6, wherein the nitrogen-containing gas having the NO bond is one of NO and NO ₂ . 14. The method according to claim 6, further comprising, after the step of forming the boron-containing silicon oxide film, exposing the boron-containing silicon oxide film to plasma of oxygen gas. 15. The film forming method according to claim 14, further comprising, after the step of exposing the boron-containing silicon oxide film to oxygen gas plasma, exposing the boron-containing silicon oxide film to ammonia gas plasma. Method. 16. A silicon oxide film having good moisture resistance on the boron-containing silicon oxide film after the step of forming the boron-containing silicon oxide film by the film forming method according to claim 6. Alternatively, a method for manufacturing a semiconductor device, comprising a step of forming a boron-containing silicon oxide film. 17. A step of forming a recess or an opening in the boron-containing silicon oxide film after the step of forming the boron-containing silicon oxide film by the film forming method according to claim 6. Embedding a copper layer in the concave portion or the opening. 18. A step of forming the boron-containing silicon oxide film by the film forming method according to claim 6, and a step of forming a wiring layer on the boron-containing silicon oxide film. A method of manufacturing a semiconductor device.