JPH09326386A - Forming method of interlayer insulating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an interlayer insulating film whose specific dielectric constant can be set at an arbitrary low value and, further, which has stable characteristics by a simple process. SOLUTION: When raw monomers A and B are vaporized in a vacuum and deposited and polymerized on a substrate 4, SiO2 which is vaporizing material 100 is deposited on the substrate 4 to form a composite film and, further, the composite film is subjected to the application of an ultraviolet radiation and a heat treatment for the cross-linking reaction and the polymerization. Diamine such as 4,4'-diaminodiphenylmethane (MDA), etc., and diisocyanate such as 4,4'-diphenylmethane diioscyanate (MDI) are used as the raw monomers A and B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating film having a low relative dielectric constant used as, for example, an interlayer insulating film of a semiconductor device, and more particularly to a composite film utilizing vapor deposition polymerization.

[0002]

2. Description of the Related Art Conventionally, as an interlayer insulating film of a semiconductor device, an SOG (Spin on Glass) film or a CV
A SiO ₂ film formed by the D method (Chemical Vapor Deposition method: Chemical Vapor Deposition) is mainly used. The relative permittivity of the interlayer insulating film formed by these methods is about 4, but recently, a reduction in the relative permittivity of the interlayer insulating film has become a major issue due to the progress of high integration of LSI, and the relative permittivity is increased. An interlayer insulating film having a rate of 4 or less is required.

To meet such demands, in recent years, a SiOF film in which fluorine is added to a SiO ₂ film formed by a plasma CVD method has been proposed. According to this film, the relative dielectric constant of the interlayer insulating film is increased. It can be suppressed to about 3.7 to 3.2.

[0004]

However, such a conventional technique has the following problems. That is, while the SiOF film formed by the above-mentioned plasma CVD method can achieve a low relative dielectric constant, the film characteristics greatly differ depending on the film forming method and the film forming conditions, and the desorption and the hygroscopicity of fluorine in the film are large. It has been pointed out that the dielectric constant deteriorates due to the instability of the film, and it is difficult to apply it as a low dielectric constant material in the future.

Further, since the SOG film formed by the spin coating method is formed by baking at a temperature near 400 ° C. to remove the organic solvent and carrying out a dehydration polymerization reaction, there is a problem that an organic solvent and water are generated. .

On the other hand, depending on the semiconductor device used,
There is a growing demand for interlayer insulating films having various relative dielectric constants.

The present invention has been made in order to solve the problems of the prior art as described above, and an interlayer insulating film having a low relative dielectric constant and having stable characteristics in a simple process can be obtained. It is an object of the present invention to provide a method for forming the.

Another object of the present invention is to provide a method for forming an interlayer insulating film, which can change the relative dielectric constant as needed.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have performed ultraviolet irradiation on a composite film formed by vapor deposition polymerization of raw material monomers and vapor deposition of SiO ₂ and ( Or) by performing heat treatment, a low relative dielectric constant thin film having stable characteristics can be obtained in a simple process,
Moreover, they have found that a desired relative dielectric constant value is achieved, and completed the present invention.

The invention according to claim 1 is based on such knowledge, and when the raw material monomer is evaporated in a vacuum and vapor-deposited and polymerized on the substrate, Si is added to the substrate.
O ₂ is vapor-deposited to form a composite film, and further, the relative dielectric constant of the polymer part is smaller than that of the SiO ₂ part,
It is characterized in that the above-mentioned composite film is irradiated with ultraviolet rays and / or heat-treated to carry out a crosslinking reaction and / or a high molecular weight.

In this case, as in the second aspect of the present invention,
In the invention of claim 1, wherein, at the same time performs the deposition of SiO ₂ and vapor deposition polymerization of the raw material monomer, SiO ₂ for the polymer portion
It is also effective to adjust the ratio of parts.

When the raw material monomer is evaporated in a vacuum and vapor-deposited and polymerized on the substrate as in the third aspect of the present invention, SiO ₂ , SiN or SiO ₂ or SiN A thin film of SiON is formed to form a composite film, and the relative dielectric constant of the polymer portion is SiO ₂ , Si
The above-mentioned composite film is irradiated with ultraviolet rays and / or heat-treated so as to be smaller than the relative dielectric constant of the N or SiON part to carry out a crosslinking reaction and / or a high molecular weight, and the above-mentioned polymer part is added. It is also effective to adjust the ratio of the SiO ₂ , SiN or SiON part.

In this case, the thin film of SiO ₂ can be formed by vapor deposition, CVD, sputtering or the like. In addition, the formation of a thin film of SiN or SiON,
It can be performed by CVD or sputtering.

Further, in the case of the present invention, as described in claim 4, in the invention according to any one of claims 1 to 3, the high molecular polymer to be vapor-deposited is aromatic polyurea. Is effective in.

In this case, the raw material monomer is 4,4'-
Diamines such as diaminodiphenyl ether, 4,4′-diamino 3,3′-dimethyldiphenylmethane, 4,4′-diaminodiphenylmethane (MDA) and 4,4′-diaminodiphenyl sulfide, and 4,4′-diphenylmethane diisocyanate Diisocyanates such as (MDI), methylenediphenyl 4,4'-diisocyanate, and 3,3'-dimethyldiphenyl 4,4'-diisocyanate can be used.

In particular, according to the invention of claim 5, 4,4'-diaminodiphenylmethane (M
DA) and 4,4'-diphenylmethane diisocyanate (M
It is more effective to use DI).

Further, according to the present invention, as described in claim 6, in the invention according to any one of claims 1 to 3, when the high molecular polymer to be vapor-deposited is an aromatic polyimide. It is effective.

In this case, the raw material monomer is 2,2'-
Bis [4- (4-aminophenoxy) phenyl] propane (BA
PP), 4,4'-diaminodiphenyl ether, 4,4'-diamino 3,3'-dimethyldiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, and other diamines, and pyromellitic dianhydride. , 3,3′4,
It is effective to use an acid anhydride such as 4'-benzophenonetetracarboxylic acid.

In particular, according to the invention of claim 7, 2,2′-bis [4- (4-aminophenoxy)) is used as a raw material monomer.
It is more effective to use phenyl] propane (BAPP) and pyromellitic dianhydride.

The wavelength of ultraviolet rays to be irradiated for lowering the relative dielectric constant is i-line (365 nm), KrF excimer laser (248 nm), ArF excimer laser (193n).
m) or the like having a selected wavelength can be used.

Further, as in the eighth aspect of the invention, in the invention of any one of the first to seventh aspects, it is also effective to perform the heat treatment at a temperature higher than the maximum temperature when manufacturing the semiconductor device. Is.

For example, heat treatment may be performed at a temperature of about 400 ° C. for about 30 minutes. In this case, the processing atmosphere may be air or vacuum.

On the other hand, it is also effective to form an interlayer insulating film on the semiconductor substrate on which the metal wiring is formed by the method according to any one of claims 1 to 8 as in the invention according to claim 9. Is.

Evaporating a plurality of raw material monomers in a vacuum,
When these are vapor-deposited and polymerized on a substrate to form a low molecular weight film, an oligomer-like vapor-deposited film having a relative dielectric constant of less than about 4 can be obtained. However, when this vapor-deposited film is irradiated with ultraviolet rays and / or heat-treated. At the same time that the unreacted terminal group reacts to increase the molecular weight, the binding portion undergoes a cross-linking reaction to change the binding portion, and the relative dielectric constant decreases to around 3.

In particular, when a polyurea film is formed by using a diamine such as MDI and a diisocyanate such as MDA as raw material monomers, when the polyurea film is irradiated with ultraviolet rays and heat-treated, unreacted end groups are not formed. At the same time as the increase in the molecular weight by the reaction of (1), the urea binding part changes due to the cross-linking reaction of the urea binding part, and the relative dielectric constant decreases to around 2 and 8.

Therefore, when the raw material monomer is evaporated in vacuum and vapor-deposited and polymerized on the substrate as in the invention described in claim 1, SiO ₂ is vapor-deposited on the substrate to form a composite film. Further, the above composite film is irradiated with ultraviolet rays and / or heat-treated so that the relative dielectric constant of the polymer portion becomes smaller than the relative dielectric constant of the SiO ₂ portion, and the crosslinking reaction and / or
When the molecular weight is increased, the relative dielectric constant of the film can be lowered as compared with the case where SiO ₂ is vapor-deposited alone on the substrate.

Further, according to the invention described in claim 1, the baking step of the SOG film by the spin coating method is not necessary, and water is not generated. Further, unlike the SiOF film formed by the plasma CVD method, the problem of deterioration of characteristics due to instability of the film does not occur, and simple equipment is sufficient.

In this case, as in the invention described in claim 2,
In the invention of claim 1, wherein, at the same time performs the deposition of SiO ₂ and vapor deposition polymerization of the raw material monomer, SiO ₂ for the polymer portion
By adjusting the ratio of the parts, the relative permittivity of the composite film can be arbitrarily changed between the relative permittivity of the polymer and SiO ₂ .

When the raw material monomer is evaporated in a vacuum and vapor-deposited and polymerized on the substrate as in the third aspect of the present invention, SiO ₂ , SiN or SiO ₂ or SiN A thin film of SiON is formed to form a composite film, and the relative dielectric constant of the polymer portion is SiO ₂ , Si
The above-mentioned composite film is irradiated with ultraviolet rays and / or heat-treated so as to be smaller than the relative dielectric constant of the N or SiON part to carry out a crosslinking reaction and / or a high molecular weight, and the above-mentioned polymer part is added. By adjusting the ratio of the SiO ₂ , SiN or SiON portion, the relative permittivity of the composite film can be arbitrarily changed between the polymer and the relative permittivity of SiO ₂ , SiN or SiON.

Further, as in the invention described in claim 4, in the invention described in any one of claims 1 to 3, when the high molecular polymer to be vapor-deposited is aromatic polyurea,
In particular, according to the invention of claim 5, 4,4'-diaminodiphenylmethane (MDA) is used as a raw material monomer,
When 4'-diphenylmethane diisocyanate (MDI) is used, a composite film of SiO ₂ and polyurea having a low relative dielectric constant can be easily obtained.

Further, as in the invention described in claim 6, in the invention described in any one of claims 1 to 3, when the high molecular polymer to be vapor-deposited is an aromatic polyimide, particularly, In the case of using 2,2'-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) as raw material monomers and pyromellitic dianhydride as in the invention of 7, the low relative dielectric constant A composite film of SiO ₂ and polyimide can be easily obtained.

In addition, as in the invention described in claim 8, in the invention described in any one of claims 1 to 7, if the heat treatment is performed at a temperature higher than the maximum temperature when manufacturing the semiconductor device, In the manufacturing process of the semiconductor device, it is possible to prevent the polymer portion from being decomposed.

On the other hand, when the interlayer insulating film is formed by the method according to any one of claims 1 to 8 on the semiconductor substrate on which the metal wiring is formed as in the invention according to claim 9, it is currently used. It is possible to obtain an interlayer insulating film having an arbitrary relative dielectric constant (3 to 4) lower than that of the SOG film and the SiO ₂ film used.

[0034]

Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an example of a film forming apparatus for carrying out the present invention. As shown in FIG. 1, in this apparatus, first and second processing chambers 1 and 2 are provided, and these first and second processing chambers 1 and 2 are connected via a gate valve 3. There is. The first and second processing chambers 1 and 2 are connected to a vacuum exhaust system such as a vacuum pump (not shown).

A substrate 4 to be processed is provided in the first processing chamber 1.
Is held by the substrate holder 5. The substrate holder 5 is attached to a distal end 6a of a transfer arm 6 that is disposed to penetrate outside the first processing chamber 1. The transfer arm 6 is configured to be movable in the horizontal direction as the transfer motor 7 rotates. That is, while the threaded portion is formed on the shaft 8 of the carry motor 7, the threaded portion is also formed on the tip end portion 6a of the carry arm 6, and the meshing of these causes the carry arm 6 to move in the arrow direction to move the substrate 4 to the first position. It is configured so as to enter the two processing chambers 2.

An electron beam heating source 9 is arranged below the first processing chamber 1. An evaporation material 10, for example, aluminum is placed on the electron beam heating source 9. Then, the electron beam EB emitted from the electron beam source 9a is deflected by the deflection magnetic field and reaches the evaporation material 10.

Further, a shutter 11 is provided between the substrate 4 and the electron beam heating source 9, and a film for detecting the thickness of a thin film formed on the substrate 4 is provided in the vicinity of the shutter 11. A thickness monitor 12 is provided.

On the other hand, below the second processing chamber 2, in order to form a polyurea film, a polyimide film, etc., two types of monomer evaporation sources 13A and 13B and an electron beam heating source 90 similar to the above are respectively provided. Will be placed.

Here, the evaporation container 15 is provided in each of the housings 14A and 14B of the evaporation sources 13A and 13B.
A and 15B are provided. And each evaporation container 15
Monomers A and B are respectively injected into A and 15B, and heaters 16A for heating the monomers A and B are provided in the vicinity of the evaporation containers 15A and 15B, respectively.
16B is provided. Further, a partition plate 17 is disposed between the evaporation sources 13A and 13B to prevent the vapors of the monomers A and B from being mixed with each other and to prevent the influence of heat from each other.

On the upper part of the electron beam heating source 90, SiO _{2 as the} evaporation material 100 is placed. Then, the electron beam EB emitted from the electron beam source 90 a is deflected by the deflection magnetic field and reaches the evaporation material 91. In addition, the evaporation source 13
A partition plate 17 is arranged between A and the electron beam heating source 90 to prevent the monomer A and the vapor of SiO ₂ from mixing with each other and to prevent the influence of heat from each other.

On the other hand, a shutter 18 is provided above the electron beam heating source 90 and evaporation sources 13A and 13B, and film thickness monitors 12A and 12B are provided near the shutter 18, respectively.

When a composite film is formed on the substrate 4 using this apparatus, the gate valve 3 is opened and the motor 7 is rotated to convey the substrate 4 to the processing chamber 2. Then, with the shutter 18 closed, the pressure in the second processing chamber 2 is set to a predetermined value, and the heater 16A, while measuring the evaporation amount of each raw material monomer A, B with the film pressure monitors 12A, 12B,
The raw material monomers A and B are heated to a predetermined temperature by 16B.

Next, after each of the raw material monomers A and B reaches a predetermined temperature to obtain a required amount of evaporation, the evaporation material 91 of the electron beam heating source 90, SiO ₂ , is heated by a predetermined power and evaporated. Let After that, shutter 1
8 is opened, a composite film of SiO ₂ and a high molecular polymer is vapor-deposited on the substrate 4 at a predetermined deposition rate, and after the deposition, the shutter 1
Close 8.

After that, the substrate 4 is taken out from the second processing chamber 2, and ultraviolet rays having a wavelength of 230 nm to 500 nm are applied to the entire surface of the composite film for a predetermined time (in the case of polyurea) and heat treatment is performed to carry out a crosslinking reaction. By increasing the molecular weight, the relative permittivity of the polymer portion is made lower than that of the SiO ₂ portion. In this case, the heat treatment condition is that the temperature is about 400 ° C. and the time is about 30 minutes. Further, the processing atmosphere may be either air or vacuum.

According to this embodiment as described above, an insulating film having a low relative dielectric constant and stable characteristics can be obtained.

2A to 2E show an example of a process of forming an interlayer insulating film of a semiconductor device using the present invention. First, as shown in FIG. 2A, a semiconductor substrate 20,
A silicon thermal oxide film 21 formed on the surface of the semiconductor substrate 20 and having a window opened at a predetermined position, and a patterned first layer wiring 22 formed on the silicon thermal oxide film 21 are formed of, for example, Si. A substrate 31 is prepared.

On the surface of the substrate 31, a composite film of polyurea or polyimide and SiO ₂ is formed over the entire surface to a desired thickness by the above-mentioned method to form an interlayer insulating film 23,
The interlayer insulating film 23 is irradiated with ultraviolet rays 24 (in the case of polyurea) and heat-treated (FIG. 2 (b)), cross-linking reaction and / or
Increase the molecular weight.

Next, a resist film 25 having a predetermined pattern is formed on the surface of the interlayer insulating film 23 (FIG. 2C), and dry etching is performed to expose the interlayer exposed in the window opening portion of the resist film 25. The insulating film 23 is removed (FIG. 2
(d)). Then, after removing the resist film 25 described above,
A wiring thin film is formed on the entire surface and patterned to form the second-layer wiring 26. Then, the wiring 22 of the first layer and the wiring 26 of the second layer are electrically connected at the window opening portion 27 where the interlayer insulating film 23 is removed, and as a result, the semiconductor device 35 having the multilayer wiring is formed. Can be obtained (Fig. 2
(e)).

According to the present embodiment, since the interlayer insulating film 23 is composed of the composite film having a low relative dielectric constant, the first layer wiring 22 and the second layer wiring 26 are connected to each other. The capacity of the formed capacitor is reduced, and the semiconductor device 35
It is possible to improve the operation speed of. Moreover, according to the present embodiment, various semiconductor devices having stable characteristics can be obtained.

The present invention is not limited to the above-described embodiment, but various changes can be made. For example,
In the above-mentioned embodiment, the vapor deposition polymerization of the raw material monomers and the vapor deposition of SiO ₂ are carried out at the same time, but they may be carried out alternately. In that case, for example, CV
The SiO ₂ film can be formed by D, sputtering, or the like.

Further, vapor deposition polymerization of raw material monomers and CV
It is also possible to form a composite film by alternately depositing SiN, SiON, etc. by D, sputtering or the like.

Further, the ratio of the polymer part to the SiO ₂ part (film thickness ratio) may be changed to various values. Thereby, the relative permittivity of the composite film can be made arbitrary.

Furthermore, the present invention can be applied not only to the interlayer insulating film but also to various insulating films.

[0055]

EXAMPLES Hereinafter, specific examples of the present invention will be described together with comparative examples.

An interlayer insulating film was formed on the substrate 4 by using the film forming apparatus shown in FIG. First, attach the substrate holder 5 to the length 7
A substrate 4 made of, for example, Corning # 7059 having a size of 6 mm × width of 26 mm × thickness of 1.0 mm is attached, and aluminum as an evaporation material 10 is evaporated by electron beam (E / B) heating of 7 in a processing chamber 1 to monitor a film thickness. A lower electrode is formed on the substrate 4 by controlling the evaporation rate at 12 so as to have a thickness of 1000 Å. In this case, the gate valve 3 was closed, the temperature of the substrate 4 was kept at 20 ° C., and the pressure in the first processing chamber 1 during vapor deposition was set to 3 × 10 ⁻³ Pa.

Next, the gate valve 3 is opened and the motor 7
Is rotated to transfer the substrate 4 to the second processing chamber 2,
Deposit the composite film on top. In this case, the raw material monomers A and B
And 4,4′-diaminodiphenylmethane (MDA), which is a raw material monomer for forming a polyurea film,
MDA was 1 in high vacuum (3 × 10 ⁻³ Pa) using 4,4′-diphenylmethane diisocyanate (MDI).
00.0 ± 0.1 ° C, 70.5 ± for MDI
Evaporate at a temperature of 0.1 ° C and monitor film thickness 12A, 12B
The evaporation rate of each monomer was controlled by.

Simultaneously with the evaporation of the raw material monomers A and B, the electron beam heating source 90 heats and evaporates SiO ₂ as the evaporation material 91, and both are evaporated on the substrate 4 to form a composite film.

In this example, the composition ratio of MDA and MDI was controlled so that the stoichiometric ratio was 1: 1. Further, the film thickness ratio of SiO ₂ and polyurea was controlled to be 1: 1.

Then, the substrate 4 is taken out of the apparatus, and 23
The entire surface of the composite film was irradiated with ultraviolet rays having a wavelength of 0 nm to 500 nm, and heat treatment was performed to carry out a crosslinking reaction and a high molecular weight. In this case, the ultraviolet irradiation time was 30 minutes, and the heat treatment temperature was 400 ° C.

After the ultraviolet irradiation and the heat treatment, the substrate 4 is again inserted into the first processing chamber 1 and aluminum is vapor-deposited under the same conditions as in the case of the lower electrode described above to form the upper electrode. A device for measurement was prepared. The relative dielectric constant of the composite film of this device was measured and found to be 3.35. In this case, the value of the relative permittivity is the multi frequency LCR meter (model 427 manufactured by Yokogawa Hewlett-Packard Co.).
5A) was used to measure the capacitance C and was calculated.

On the other hand, as a comparative example, a lower electrode and a composite film were formed by the same method as that of the embodiment, and an upper electrode was formed on the composite film without irradiation of ultraviolet rays and heat treatment, and the relative dielectric constant was measured. The element of was created. When the relative permittivity of the composite film was measured for this device by the same method as in Example,
It was around 4.0.

As described above, the composite film irradiated with ultraviolet rays is
After the irradiation time of 30 minutes, the dielectric constant was 3.35, which was lower than that of the film not irradiated with ultraviolet rays and the non-heat treated film. From this, it was clarified that the relative permittivity of the composite film can be lowered by irradiating with ultraviolet rays and heat treatment.

When this composite film was left in the atmosphere, a change in capacity of 1% was observed after 1 week due to moisture absorption. In order to prevent this change in capacity, a glow discharge treatment was performed after forming the composite film by the above method and irradiating it with ultraviolet rays. In this case, Ar is used as the gas and the pressure is 0.666.
RF of 200 W at 61 Pa (= 0.005 Torr)
Processing was performed for 10 seconds with electric power. As a result, the capacity change when left in the air for 1 week was 0.5% or less, and improvement in hygroscopicity was confirmed.

[0065]

As described above, according to the first aspect of the present invention, when the raw material monomer is evaporated in vacuum and vapor deposition polymerization is performed on the substrate, SiO ₂ is vapor-deposited on the substrate to form a composite. A film is formed, and the relative dielectric constant of the polymer part is Si
By subjecting the above composite film to irradiation of ultraviolet rays and / or heat treatment so as to be smaller than the relative dielectric constant of O ₂ part to carry out a crosslinking reaction and / or a high molecular weight, SiO ₂ alone is applied onto a substrate. An interlayer insulating film having a lower relative dielectric constant than that obtained by vapor deposition can be obtained.

Further, according to the invention described in claim 1, since the baking step of the SOG film by the spin coating method is not necessary and no water is generated, the steps can be simplified. Further, it is possible to solve the problem of cost increase due to the deterioration of characteristics due to the instability of the film and the increase in complexity of the device like the SiOF film formed by the plasma CVD method.

In this case, as in the invention described in claim 2,
In the invention of claim 1, wherein, at the same time performs the deposition of SiO ₂ and vapor deposition polymerization of the raw material monomer, SiO ₂ for the polymer portion
By adjusting the ratio of the parts, an interlayer insulating film having a desired relative dielectric constant between the polymer and the relative dielectric constant of SiO ₂ can be obtained.

When the raw material monomer is evaporated in a vacuum and vapor-deposited and polymerized on the substrate as in the third aspect of the present invention, SiO ₂ , SiN, or SiN A thin film of SiON is formed to form a composite film, and the relative dielectric constant of the polymer portion is SiO ₂ , Si
The above-mentioned composite film is irradiated with ultraviolet rays and / or heat-treated so as to be smaller than the relative dielectric constant of the N or SiON part to carry out a crosslinking reaction and / or a high molecular weight, and the above-mentioned polymer part is added. By adjusting the ratio of the SiO ₂ , SiN or SiON portion, an interlayer insulating film having a desired relative dielectric constant between the polymer and the relative dielectric constant of SiO ₂ , SiN or SiON can be obtained. The versatility can be expanded.

Further, as in the invention described in claim 4, in the invention described in any one of claims 1 to 3, when the high molecular polymer to be vapor-deposited is aromatic polyurea,
In particular, according to the invention of claim 5, 4,4'-diaminodiphenylmethane (MDA) is used as a raw material monomer,
By using 4'-diphenylmethane diisocyanate (MDI), a composite film of SiO ₂ and polyurea having a low relative dielectric constant can be easily formed.

Further, as in the invention described in claim 6, in the invention described in any one of claims 1 to 3, when the high molecular polymer to be vapor-deposited is an aromatic polyimide, particularly, As in the invention described in 7, the use of 2,2′-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) as raw material monomers and pyromellitic dianhydride facilitates the low relative dielectric constant. It is possible to form a composite film of SiO ₂ and polyimide.

In addition, as in the invention described in claim 8, in the invention described in any one of claims 1 to 7, the heat treatment is performed at a temperature higher than the maximum temperature for manufacturing the semiconductor device. In the subsequent manufacturing process of the semiconductor device, the decomposition of the polymer component can be avoided, and the characteristics of the interlayer insulating film can be stabilized.

On the other hand, as in the invention described in claim 9, the interlayer insulating film is formed by the method according to any one of claims 1 to 8 on the semiconductor substrate on which the metal wiring is formed. An interlayer insulating film having an arbitrary relative dielectric constant lower than that of the SOG film or SiO ₂ film used can be obtained. Therefore, by forming an interlayer insulating film of a multi-layer wiring by using the present invention, various semiconductor devices having a high operation speed and stable characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an example of a film forming apparatus for carrying out the present invention.

2A to 2E are process diagrams showing an example of a process of forming an interlayer insulating film of a semiconductor device by using the present invention.

[Explanation of symbols]

1 ... 1st process chamber, 2 ... 2nd process chamber, gate valve,
4 ... Substrate, 5 ... Substrate holder, 9 ... Electron beam heating source, 9a ... Electron beam source, 10 ... Evaporation material (aluminum), 12, 12A, 12B ... Film thickness monitor, 13A, 13B ... Evaporation source, 15A, 15B ... evaporation container, 16A, 16B ... heater, 18 ... shutter,
20 ... Semiconductor substrate, 21 ... Silicon thermal oxide film, 22 ... Wiring, 23 ... Interlayer insulating film, 24 ... Ultraviolet ray, 25 ... Resist film, 26 ... Wiring, 31 ... Substrate, 35 ... Semiconductor device, 90
... Electron beam heating source, 90a ... electron beam source, 100 ... evaporation material _{(SiO 2), A, B} ... raw material monomer, EB ... Electron beam

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // C23C 16/30 H01L 21/90 K

Claims (9)

[Claims] 1. When a raw material monomer is evaporated in a vacuum and vapor-deposited and polymerized on a substrate, SiO ₂ is vapor-deposited on the substrate to form a composite film, and the relative dielectric constant of the polymer portion is Si.
A method for forming an interlayer insulating film, which comprises subjecting the composite film to irradiation of ultraviolet rays and / or heat treatment so as to be smaller than the relative permittivity of O ₂ part to carry out a crosslinking reaction and / or a high molecular weight. _2. The method for forming an interlayer insulating film according to claim 1, wherein SiO ₂ is vapor-deposited simultaneously with vapor deposition polymerization of the raw material monomer to adjust the ratio of the SiO ₂ part to the polymer part. 3. A composite film formed by evaporating a raw material monomer in a vacuum and vapor-depositing and polymerizing the raw material monomer on the substrate, alternately forming a thin film of SiO ₂ , SiN or SiON on the substrate. Further, the composite film is subjected to ultraviolet irradiation and / or heat treatment so that the relative dielectric constant of the polymer portion becomes smaller than the relative dielectric constant of the SiO ₂ , SiN or SiON portion, and the crosslinking reaction and ( Or) A method for forming an interlayer insulating film, which comprises increasing the molecular weight to adjust the ratio of the SiO ₂ , SiN or SiON portion to the polymer portion. 4. The method for forming an interlayer insulating film according to claim 1, wherein the high molecular polymer to be vapor-deposited and polymerized is aromatic polyurea. 5. The formation of an interlayer insulating film according to claim 4, wherein 4,4'-diaminodiphenylmethane (MDA) and 4,4'-diphenylmethane diisocyanate (MDI) are used as raw material monomers. Method. 6. The method for forming an interlayer insulating film according to claim 1, wherein the high molecular weight polymer to be vapor-deposited and polymerized is an aromatic polyimide. 7. The interlayer insulation according to claim 6, wherein 2,2'-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) and pyromellitic dianhydride are used as raw material monomers. Method of forming a film. 8. The heat treatment is performed at a temperature higher than the maximum temperature for manufacturing a semiconductor device.
9. The method for forming an interlayer insulating film according to any one of 1. 9. A method of forming an interlayer insulating film, comprising the step of forming a composite film by the method according to claim 1 on a semiconductor substrate having a metal wiring formed thereon.