JP2007165914A - Composition for forming low dielectric constant film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide composition or the like for forming a low dielectric constant film capable of forming a film with high strength and low dielectric constant. <P>SOLUTION: The composition for forming a low dielectric constant film contains at least polysiloxane which is a hydrolysis product of alkoxysilane represented by a general formula (1), and two or more radiolytic compounds maximum absorption wavelengths of which are different from each other. Here, X in the general formula (1) represents at least one of a hydrogen atom, a fluorine atom, alkyl group, aryl group, vinyl group and alicyclic group. R represents at least one of a hydrogen atom, alkyl group, aryl group, vinyl group and alicyclic group. An 'n' represents an integer of 0 to 3. There are preferable aspects such as an aspect in which a content of the radiolytic compound is 0.1 to 200 parts by mass to 100 parts by mass of the polysiloxane, an aspect which contains two or more radiolytic compounds maximum absorption wavelengths of which are different from each other, an aspect which contains two or more radiolytic compounds molecule sizes of which are different from each other, or the like. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a composition for forming a low dielectric constant film suitable for multilayer wiring in a semiconductor integrated circuit.

In recent years, with the increase in the degree of integration of semiconductor integrated circuits and the improvement in device density, there has been a growing demand for multilayered semiconductor devices. As the semiconductor integrated circuit is highly integrated, the wiring interval is further narrowed. Therefore, a wiring delay due to an increase in capacitance between the wirings is a problem. Here, the wiring delay (T) is expressed by the following expression (1), T∝CR (1), and is affected by the wiring resistance (R) and the capacitance (C) between the wirings. . The relationship between the dielectric constant (ε) and the capacitance (C) between the wirings is expressed by the following equation (2), C = ε ₀ ε _r · S / d (2). The In the above formula (2), S represents the electrode area, ε ₀ represents the vacuum dielectric constant, ε _r represents the dielectric constant of the insulating film, and d represents the wiring interval.

  The capacitance (C) between the wirings can be reduced by reducing the wiring thickness and reducing the electrode area. However, if the wiring thickness is reduced, the wiring resistance (T) is further increased, thereby achieving high speed. I don't get it. Therefore, in order to reduce the wiring delay (T) and increase the speed, lowering the dielectric constant of the insulating film is an effective means.

Conventionally, inorganic films such as silicon dioxide (SiO ₂ ), silicon nitride (SiN), phosphosilicate glass (PSG), and organic polymers such as polyimide have been used as the insulating film. .

However, even with CVD-SiO ₂ film, which is frequently used in semiconductor devices, the dielectric constant is as high as about 4, and in SiOF film being considered as a low dielectric constant CVD film has a dielectric constant of about 3.3 to 3 However, there was a problem that the hygroscopicity was high and the dielectric constant was increased.

Furthermore, as the low dielectric constant film, a porous film obtained by making a siloxane resin porous has been proposed.
However, in the case of this porous film, it is manufactured through a process of promoting polymerization of polysiloxane, a process of heating and decomposing a thermally decomposable resin to form pores, etc., and these processes are performed at a temperature of 300 to 500 ° C. Therefore, when the porous film is applied to a semiconductor device, the wiring in the semiconductor device is disconnected due to thermal stress, and the wiring material diffuses into the porous film. there were. Therefore, in the wiring process in the manufacturing process of the semiconductor device, a composition for forming a low dielectric constant film that reduces thermal stress and improves the reliability of a device such as a semiconductor device, a method for manufacturing the low dielectric constant film, etc. Development is desired.

  An object of the present invention is to solve various problems in the prior art and achieve the following objects. That is, an object of the present invention is to provide a composition for forming a low dielectric constant film capable of forming a film having a high strength and a low dielectric constant.

Means for solving the problems are as follows.
<1> A polysiloxane that is a hydrolysis product of an alkoxysilane represented by the following general formula (1) and at least two or more kinds of radiation-decomposable compounds having different absorption maximum wavelengths, This is a composition for forming a low dielectric constant film.
In the general formula (1), X represents at least one of a hydrogen atom, a fluorine atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. R represents at least one of a hydrogen atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. n represents an integer from 0 to 3.
<2> A polysiloxane that is a hydrolysis product of an alkoxysilane represented by the following general formula (1) and at least two or more kinds of radiation-decomposable compounds having different molecular sizes. It is a composition for forming a low dielectric constant film.
In the general formula (1), X represents at least one of a hydrogen atom, a fluorine atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. R represents at least one of a hydrogen atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. n represents an integer from 0 to 3.
<3> At least a polysiloxane that is a hydrolysis product of an alkoxysilane represented by the following general formula (1) and at least two or more kinds of radiation-decomposable compounds having different absorption maximum wavelengths and molecular sizes. Is a composition for forming a low dielectric constant film.
In the general formula (1), X represents at least one of a hydrogen atom, a fluorine atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. R represents at least one of a hydrogen atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. n represents an integer from 0 to 3.
<4> The content of the radiation-decomposable compound in the composition for forming a low dielectric constant film is 0.1 to 200 parts by mass with respect to 100 parts by mass of the polysiloxane, according to any one of <1> to <3> The composition for forming a low dielectric constant film described above.
<5> From the above <1>, wherein the radiolytic compound is selected from at least one of a triarylsulfonium salt represented by the following general formula (2) and a diaryl iodonium salt represented by the following general formula (3) <4> The composition for forming a low dielectric constant film according to any one of <4>.
In the general formula (2) and the general formula (3), each R ² independently represents at least one of a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, or an alkoxy group. Represents.
<6> The composition for forming a low dielectric constant film according to any one of <1> to <5>, which contains a silicone compound containing a hydrocarbon in a skeleton.
<7> The content ratio of the radiation-decomposable compound having a large absorption maximum wavelength and the radiation-decomposable compound having a small absorption wavelength among two or more types having different absorption maximum wavelengths (radiodegradable compound having a large absorption maximum wavelength / absorption) The composition for forming a low dielectric constant film according to <1>, wherein the radiation-decomposable compound having a small wavelength is 1/100 to 100/1.
<8> The content ratio of the radiolytic compound having a large molecular size and the radiolytic compound having a small molecular size among the two types of radiolytic compounds having different molecular sizes (radiolytic compound having a large molecular size) The composition for forming a low dielectric constant film according to the above <2>, wherein the (/ radiolytic compound having a small molecular size) is 1/100 to 100/1.
<9> The content according to <6>, wherein the content of the silicone compound containing a hydrocarbon in the skeleton is 0.1 to 200 parts by mass with respect to 100 parts by mass of the polysiloxane. A composition for forming a dielectric constant film.

  ADVANTAGE OF THE INVENTION According to this invention, the conventional problems can be solved and the composition for low dielectric constant film formation which can form a high intensity | strength and low dielectric constant film | membrane can be provided.

(Composition for forming low dielectric constant film)
The composition for forming a low dielectric constant film of the present invention contains at least polysiloxane and a radiation-decomposable compound, and further contains other components as necessary.

-Polysiloxane-
The polysiloxane is a hydrolysis product of an alkoxysilane represented by the following general formula (1).
In the general formula (1), X represents at least one of a hydrogen atom, a fluorine atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. R represents at least one of a hydrogen atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. n represents an integer from 0 to 3. The group represented by X or R may be further substituted with another substituent. In addition, there is no restriction | limiting in particular as said alkyl group, Although it can select suitably according to the objective, A C1-C8 alkyl group is preferable.

  The polysiloxane is not particularly limited as long as it can be diluted with a predetermined solvent, and can be appropriately selected according to the purpose. For example, tetraalkoxysilane sol-gel polymer, trialkoxysilane sol-gel polymer, methyltrimethyl Sol-gel polymer of alkoxysilane, sol-gel polymer of tetraalkoxysilane and trialkoxysilane, sol-gel polymer of tetraalkoxysilane and methyltrialkoxysilane, sol-gel polymer of methyltrialkoxysilane and trialkoxysilane, sol-gel of tetraalkoxysilane and dimethylalkoxysilane Examples thereof include polymers, hydrogen silsesquioxanes, methyl silsesquioxanes, fluorine-containing hydrogen silsesquioxanes, and the like. These may be used alone or in combination of two or more.

-Radiolytic compounds-
The radiation-decomposable compound is not particularly limited as long as it can be decomposed and eliminated when irradiated with radiation, and can be appropriately selected according to the purpose. Examples thereof include diaryl iodonium salts and triarylsulfonium. Examples thereof include salts, triarylselenonium salts, acrylic resins, novolac resins, epoxy resins, polyesters, polypropylenes, phenol compounds, imidazole compounds, and adamantane compounds. Among these, the triarylsulfonium salt represented by the following general formula (2) and the diaryl iodonium salt represented by the following general formula (3) have a high quantum yield, and desorb from the film as a gas after decomposition. And particularly preferred.

In the general formula (2) and the general formula (3), each R ² independently represents at least one of a hydrogen atom, a halogen atom, a linear, branched, or cyclic alkyl group or an alkoxy group. Represents. The alkyl group or the alkoxy group preferably has 1 to 6 carbon atoms.

  Although the said radiolytic compound may be used individually by 1 type, it is preferable to use 2 or more types together. Examples of the mode in which two or more types are used in combination include a mode in which two or more types of radiolytic compounds having different absorption maximum wavelengths are used in combination, a mode in which two or more types of radiolytic compounds having different molecular sizes are used in combination, and the like. It is done. In the case of the former mode, it is possible to use two or more kinds of radiation to be irradiated when producing the low dielectric constant film, and it becomes possible to form pores in a stepwise manner and to make them porous. In the latter case, the hole size in the low dielectric constant film can be arbitrarily changed when manufacturing the low dielectric constant film. In particular, when two or more kinds of radiation-decomposable compounds having different absorption maximum wavelengths and molecular sizes are used in combination, pores having different sizes can be efficiently mixed in the same film.

In the case of the former mode, the content ratio of the radiation-decomposable compound having a large absorption maximum wavelength and the radiation-decomposable compound having a small absorption wavelength among two or more different absorption maximum wavelengths (radiation having a large absorption maximum wavelength). (Decomposable compound / radiolytic compound having a small absorption wavelength) is preferably 1/100 to 100/1.
In the case of the latter mode, the content ratio (of the molecular size) of the radiolytic compound having a large molecular size and the radiolytic compound having a small molecular size among the two types of radiolytic compounds having different molecular sizes. It is preferable that the ratio (large radiodegradable compound / radiodegradable compound having a small molecular size) is 1/100 to 100/1.

The content of the radiation-decomposable compound in the composition for forming a low dielectric constant film is preferably 0.1 to 200 parts by mass, more preferably 0.1 to 50 parts by mass with respect to 100 parts by mass of the polysiloxane. .
If the content is less than 0.1 parts by mass, the effect of reducing the dielectric constant in the formed low dielectric constant film may not be sufficient, and if it exceeds 200 parts by mass, the strength of the obtained low dielectric constant film May decrease.

-Other ingredients-
Examples of the other components include a diluent solvent, a silicone compound containing a hydrocarbon in the skeleton, and the like.

  The diluting solvent is not particularly limited as long as it can dissolve the siloxane resin, and can be appropriately selected according to the purpose. For example, cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, octane, decane. , Propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diethylene glycol, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and the like. These may be used alone or in combination of two or more.

  Silicone compounds containing hydrocarbons in the skeleton are used for the purpose of improving chemical resistance such as acid and alkali and moisture absorption resistance to the low dielectric constant film forming composition, for example, polydimethylcarbosilane, poly Hydromethylcarbosilane, polydiethylcarbosilane, polyhydroethylcarbosilane, polycarbosilastyrene, polyphenylmethylcarbosilane, polydiphenylcarbosilane, polydimethylsilphenylenesiloxane, polymethylsilphenylenesiloxane, polydiethylsilphenylenesiloxane, Polyethylsilphenylenesiloxane, polydipropylsilphenylenesiloxane, polypropylsilphenylenesiloxane, polyphenylsilphenylenesiloxane, polydiphenylsilphenylenesiloxane, polyphenylmethylsilane Phenylene siloxanes, poly phenylethyl silphenylene siloxanes, poly phenylpropyl Lucille polyphenylene siloxane, polyethyl methyl silphenylene siloxane, polymethyl propyl silphenylene siloxane, polyethyl propyl silphenylene siloxanes, and the like. These may be used alone or in combination of two or more.

The content of the silicone compound containing hydrocarbon in the skeleton in the composition for forming a low dielectric constant film is preferably 0.1 to 200 parts by mass with respect to 100 parts by mass of the polysiloxane.
When the content is less than 0.1 parts by mass, the chemical resistance effect of the obtained low dielectric constant film may not be obtained. When the content exceeds 200 parts by mass, the strength of the obtained low dielectric constant film is obtained. May decrease.

  The composition for forming a low dielectric constant film of the present invention can form a low dielectric constant film easily and efficiently, and can be suitably used in various fields. And its manufacturing method and semiconductor device can be used particularly preferably.

(Production method of low dielectric constant film)
In the method for producing a low dielectric constant film of the present invention, a coating film is formed by applying the composition for forming a low dielectric constant film of the present invention on a substrate, and the coating film is irradiated with radiation.

-Coating film-
The coating film is formed by coating the composition for forming a low dielectric constant film of the present invention on a substrate. There is no restriction | limiting in particular as this application | coating method, For example, a well-known coating method, for example, a spin coat, a dip coat, a kneader coat, a curtain coat, a blade coat etc. are mentioned. Among these, spin coating, dip coating, and the like are preferable in terms of efficiency and the like.
After the application, a solvent or the like can be dried as necessary. The drying temperature is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably about 100 to 250 ° C.

-Irradiation-
The irradiation of the radiation is performed on the coating film. When the radiation is applied to the coating film, the radiolytic compound contained in the composition for forming a low dielectric constant film is decomposed and desorbed. The coating film becomes porous.
The type of radiation is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include infrared light, visible light, ultraviolet light, and X-ray. An electron beam can also be irradiated as the radiation, and the same effect can be obtained. These may be used singly or in combination of two or more, but when the radiolytic compound is a resin, ultraviolet light is used as a light source having the energy of main chain breaking, X-rays, electron beams and the like can be used particularly preferably.

In order to efficiently decompose and desorb the radiation-decomposable compound when irradiated with the radiation, the absorbance of the coating film (the wavelength of the irradiated radiation (10 ⁻¹ to 10 −10) when irradiating the radiation. ⁶ is the absorbance at Å.) Is preferably 1.75 or less, and more preferably 1.25 or less.

  In the radiation irradiation, for example, when the composition for forming a low dielectric constant film contains two or more kinds of the radiolytic compounds having different absorption maximum wavelengths, two or more kinds of radiations are used. By irradiating the coating film, the radiolytic compound can be decomposed and desorbed from the coating film step by step for each type. As a result, the coating film can be made porous in stages. In particular, when two or more kinds of the radiolytic compounds having different absorption maximum wavelengths and molecular sizes are used in combination, it is possible to efficiently form pores having different sizes in the coating film. In this case, first, the radiation-decomposable compound having a small molecular size is irradiated with radiation in a wavelength range in which the absorption maximum is obtained, and the radiodegradable compound having a small molecular size is decomposed / desorbed from the coating film, and then In addition, the radiation-decomposable compound having a large molecular size is irradiated with radiation in a wavelength range where the absorption maximum is exhibited, and the radiation-decomposable compound having a large molecular size is decomposed / desorbed from the coating film. At this time, the radiodegradable compound having a large molecular size can be efficiently desorbed because a large number of pores are already formed in the coating film due to the decomposition and desorption of the radiodegradable compound having a small molecular size. Thus, the porous structure easily proceeds. As a result, a low dielectric constant film can be obtained very efficiently.

The coating film can be heat-treated as necessary before or simultaneously with the irradiation of the radiation.
When the heat treatment is performed, the polymerization of the polysiloxane can be promoted and the polysiloxane can be crosslinked.
There is no restriction | limiting in particular as temperature of the said heat processing, Although it can select suitably according to the objective, About 250-300 degreeC is preferable.
There is no restriction | limiting in particular as the frequency | count of the said heat processing, According to the objective, it can select suitably.

  Since the low dielectric constant film manufacturing method of the present invention can easily manufacture the low dielectric constant film without subjecting it to high temperature processing, it is possible to achieve high quality without giving thermal stress to a high-speed and highly reliable semiconductor device. The present invention can be applied to the manufacture of a semiconductor device and the like, and is particularly suitable for the following low dielectric constant film and semiconductor device of the present invention.

(Low dielectric constant film)
The low dielectric constant film of the present invention is produced by the method for producing a low dielectric constant film of the present invention.
The pore diameter (average diameter) in the low dielectric constant film is preferably 100 nm or less and more preferably 80 nm or less from the viewpoint of low dielectric constant characteristics.
The diameter (average diameter) of the holes can be measured with a transmission electron microscope.
There is no restriction | limiting in particular as thickness of the said low dielectric constant film | membrane, Although it can select suitably according to the objective, It is preferable that it is about 0.05-5 micrometers.
Since the low dielectric constant film of the present invention is excellent in low dielectric constant characteristics, it can be suitably used in various fields. However, various devices requiring high speed and reliability such as ICs, LSIs, etc. It can be particularly suitably used as a stable interlayer insulating film in an integrated semiconductor device or the like.

(Semiconductor device)
The semiconductor device of the present invention is not particularly limited other than having the low dielectric constant film of the present invention as an interlayer insulating film, and has known members and the like appropriately selected according to the purpose, and includes flash memory, DRAM, FRAM And MOS transistors are preferred.
Since the semiconductor device of the present invention has the low dielectric constant film of the present invention as an interlayer insulating film, it has excellent insulating properties between layers, high speed and high reliability, and can be suitably used in various fields.

An example of the semiconductor device of the present invention will be described below with reference to FIG. The semiconductor device of the present invention is obtained as follows, for example. That is, as shown in FIG. 1, first, a transistor layer is formed which is separated by the inter-element isolation film 2 to form the source diffusion layer 5a, the drain diffusion layer 5b, and the gate electrode 4 having the sidewall insulating film 3. An interlayer insulating film (phosphorus glass) 6 and a stopper film 7 are formed on the silicon wafer 1 to form contact holes for taking out electrodes. A barrier film 8 (TiN; 50 nm) is formed in this contact hole by a sputtering method, and then a conductive plug (W) 9 is embedded by mixing and reducing WF ₆ and hydrogen, and chemical mechanical polishing (CMP) is performed. Remove parts other than vias.

Subsequently, the composition for forming a low dielectric constant film of the present invention is applied onto the stopper film 7 by the coating method to form the low dielectric constant film 10 (thickness: 450 nm), and then TEOS-SiO ₂ (cap film). 12) is laminated to 50 nm. The cap film 12 is processed by F plasma using CF ₄ / CHF ₃ gas as a raw material with the resist layer provided with the first wiring pattern as a mask.

  In this wiring groove, a barrier film 8 (TiN) (50 nm) serving as a diffusion barrier to the Cu insulating layer and a seed layer Cu (50 nm) serving as an electrode during electrolytic plating are formed by sputtering. Further, after copper (600 nm) is laminated by electrolytic plating, the metal other than the wiring pattern portion is removed by CMP to form a layer of the copper wiring 14.

Next, a dual damascene method for simultaneously forming a via layer and a wiring layer will be described. On the first wiring layer, for the purpose of preventing Cu diffusion, a SiN film (50 nm) is formed as a diffusion preventing film 13 by plasma CVD using silane and ammonia gas, for forming the low dielectric constant film of the present invention. The composition is applied by the above application method, and a low dielectric constant film 10 (650 nm) is laminated. A SiN film (50 nm) is formed as a stopper film 7 by plasma CVD using silane and ammonia gas in the wiring layer portion, and further, the composition for forming a low dielectric constant film of the present invention is applied by the coating method. A low dielectric constant film 10 (400 nm) is formed thereon. A TEOS-SiO ₂ film is laminated as the cap film 12 (50 nm). The low dielectric constant film 10 is changed to SiO ₂ / low dielectric constant insulating film / SiN / by changing the gas composition by F plasma using CF ₄ / CHF ₃ gas as a raw material with a resist layer having a via pattern formed as a mask. Processing is performed in the order of low dielectric constant insulating film / SiN. Subsequently, using the resist layer provided with the second-layer wiring pattern as a mask, processing is performed by F plasma using CF ₄ / CHF ₃ gas as a raw material. A barrier film 8 (TiN; 50 nm) serving as a diffusion barrier to the Cu insulating layer and a seed layer Cu (50 nm) serving as an electrode during electrolytic plating are formed by sputtering in the via and the wiring groove. Further, after copper (1400 nm) is laminated by electrolytic plating, the metal other than the wiring pattern portion is removed by CMP, and the portions other than the via are removed by chemical mechanical polishing (CMP) in which the copper wiring 14 is formed. Form. Thereby, the above process can be repeated to form a three-layer wiring. Thus, in the obtained multilayer wiring, the yield of 1 million continuous vias can be 90% or more.

Examples of the present invention will be described below, but the present invention is not limited to these examples.
Example 1
-Preparation of composition for forming low dielectric constant film-
200 ml of 20.8 g (0.1 mol) of tetraethoxysilane, 17.8 g (0.1 mol) of methyltriethoxysilane, and 39.6 g of methyl isobutyl ketone were charged into a reaction vessel, and 16.2 g of 400 ppm nitric acid solution was added thereto. (0.9 mol) was added dropwise over 10 minutes, and an aging reaction was carried out for 2 hours after the completion of the addition. Next, 5 g of magnesium sulfate was added to remove excess water, and then the ethanol produced by the aging reaction was removed with a rotary evaporator until the reaction solution reached 50 ml. 20 ml of methyl isobutyl ketone was added to the obtained reaction solution, and methyl isobutyl ketone was removed by an oven at 200 ° C. to prepare a composition having a solid content concentration of 17.4% by mass. To this composition, 1.68 g of polymethyl methacrylate (5 parts by mass with respect to 100 parts by mass of polysiloxane) was added to prepare a composition for forming a low dielectric constant film.

-Production of low dielectric constant film-
The obtained composition for forming a low dielectric constant film is spin-coated (3000 rpm, 20 seconds) on a silicon wafer to form a coating film, dried at 200 ° C., and annealed at 250 ° C. for 60 minutes. It was. Thereafter, the coating film was irradiated with ultraviolet rays having a wavelength of 172 nm for 3 minutes to produce a low dielectric constant film. At this time, the absorbance in the coating film before irradiation with radiation (ultraviolet rays) was measured by a known absorbance measurement method using an ultraviolet / visible spectrophotometer (machine name: U-3200, manufactured by Hitachi). Similarly, a 1 mm Au electrode was formed on the coating film before irradiation with radiation (ultraviolet rays), and the dielectric constant of the coating film was measured and calculated by measuring the capacitance. Further, the dielectric constant of the obtained low dielectric constant film was measured in the same manner as described above. Moreover, the diameter of the hole in the low dielectric constant film was measured by a transmission electron microscope (TEM). These results are shown in Table 1.

(Example 2)
-Preparation of composition for forming low dielectric constant film-
In Example 1, a composition for forming a low dielectric constant film was prepared in the same manner as in Example 1, except that 1.68 g (5 parts by mass) of polymethyl methacrylate was replaced with 2.5 g (10 parts by mass) of the triazine derivative. Prepared.

-Production of low dielectric constant film-
Using the obtained composition for forming a low dielectric constant film, in Example 1, the irradiated radiation (ultraviolet light having a wavelength of 172 nm) was replaced with visible light having a wavelength of 400 nm, and the irradiation time was set to 5 minutes. A low dielectric constant film was produced in the same manner as in Example 1, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Example 3)
-Preparation of a composition for forming a low dielectric constant film-
200 ml of 17.8 g (0.1 mol) of methyltriethoxysilane, 16.4 g (0.1 mol) of triethoxysilane, and 37.2 g of methylisobutylketone are charged into a reaction vessel, and there are added 16.2 g of 400 ppm nitric acid solution. (0.9 mol) was added dropwise over 10 minutes, and an aging reaction was carried out for 2 hours after the completion of the addition. Next, 5 g of magnesium sulfate was added to remove excess water, and then the ethanol produced by the aging reaction was removed with a rotary evaporator until the reaction solution reached 50 ml. 20 ml of methyl isobutyl ketone was added to the obtained reaction solution, and methyl isobutyl ketone was removed by an oven at 200 ° C. to obtain a composition having a solid content concentration of 15.8% by mass. To this composition, 1.68 g of polymethyl methacrylate (5 parts by mass with respect to 100 parts by mass of polysiloxane) was added to prepare a composition for forming a low dielectric constant film.

-Production of low dielectric constant film-
Using the obtained composition for forming a low dielectric constant film, a low dielectric constant film was formed in the same manner as in Example 1, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

Example 4
-Preparation of composition for forming low dielectric constant film-
A composition for forming a low dielectric constant film was prepared in the same manner as in Example 3, except that 1.68 g (5 parts by mass) of polymethyl methacrylate was replaced with 2.5 g (10 parts by mass) of the triazine derivative. did.

-Production of low dielectric constant film-
Using the obtained composition for forming a low dielectric constant film, the irradiated radiation (ultraviolet light having a wavelength of 172 nm) was converted into visible light having a wavelength of 400 nm in “Formation of low dielectric constant film / absorbance and dielectric constant measurement” in Example 3. Instead, a low dielectric constant film was produced in the same manner as in Example 1 except that the irradiation time was changed to 5 minutes, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Comparative Example 1)
In Example 1, it was carried out similarly to Example 1 except not having added polymethylmethacrylate. The results are shown in Table 1.

(Comparative Example 2)
In Example 3, it carried out similarly to Example 3 except not having added polymethylmethacrylate. The results are shown in Table 1.

(Example 5)
In Example 3, a low dielectric constant film was produced in the same manner as in Example 3 except that the irradiated radiation (ultraviolet light having a wavelength of 172 nm) was replaced with ultraviolet light having a wavelength of 365 nm and the irradiation time was changed to 10 minutes. Evaluation similar to 3 was performed. The results are shown in Table 2.

(Example 6)
-Preparation of composition for forming low dielectric constant film-
In Example 3, a composition for forming a low dielectric constant film was prepared in the same manner as in Example 3 except that 1.68 g of polymethyl methacrylate was replaced with 2.1 g (5 parts by mass) of the triarylsulfonium derivative.

-Production of low dielectric constant film-
In Example 3, a low dielectric constant film was produced in the same manner as in Example 3 except that the irradiated radiation (ultraviolet light having a wavelength of 172 nm) was replaced with ultraviolet light having a wavelength of 254 nm and the irradiation time was changed to 1 minute. Evaluation similar to Example 3 was performed. The results are shown in Table 2.

(Example 7)
-Preparation of composition for forming low dielectric constant film-
A composition for forming a low dielectric constant film was prepared in the same manner as in Example 3 except that 2.1 g (5 parts by mass) of a triarylsulfonium derivative was further added.

-Production of low dielectric constant film-
Example 3 is the same as Example 3 except that irradiation with ultraviolet light with a wavelength of 172 nm was irradiated for 3 minutes, irradiation with ultraviolet light with a wavelength of 254 nm for 1 minute, and irradiation with ultraviolet light with a wavelength of 365 nm for 10 minutes. Then, a low dielectric constant film was produced and evaluated in the same manner as in Example 3. The results are shown in Table 2.

  In Table 2, “absorbance” indicates that in Example 7, the absorbance of the film before irradiating ultraviolet light with a wavelength of 254 nm for 1 minute is “(1) 2.5”, and before irradiation with ultraviolet light with a wavelength of 365 nm for 10 minutes. It shows that the absorbance of the film is “(2) 2.0”.

(Example 8)
A semiconductor device of the present invention comprising the low dielectric constant film of the present invention produced using the composition for forming a low dielectric constant film of the present invention was obtained as follows. That is, as shown in FIG. 1, first, a transistor layer formed by forming the gate electrode 4 having the source diffusion layer 5a, the drain diffusion layer 5b, and the sidewall insulating film 3 separated by the inter-element isolation film 2 is formed. An interlayer insulating film (phosphorus glass) 6 and a stopper film 7 were formed on the silicon wafer 1 thus formed, and contact holes for taking out the electrodes were formed. A barrier film 8 (TiN; 50 nm) is formed in the contact hole by sputtering, and then a conductive plug (W) 9 is embedded by mixing and reducing WF ₆ and hydrogen, and chemical mechanical polishing (CMP) is performed. Parts other than vias were removed.

Subsequently, a low dielectric constant film 10 (thickness: 450 nm) was formed on the stopper film 7 in the same manner as in Example 4 using the composition for forming a low dielectric constant film of Example 4, and then TEOS-SiO _2. (Cap film 12) was laminated by 50 nm. The cap film 12 was processed by F plasma using CF ₄ / CHF ₃ gas as a raw material with the resist layer provided with the first wiring pattern as a mask.

  In this wiring groove, a barrier film 8 (TiN) (50 nm) serving as a diffusion barrier to an insulating layer of Cu and a seed layer Cu (50 nm) serving as an electrode during electrolytic plating were formed by sputtering. Furthermore, after copper (600 nm) was laminated by electrolytic plating, the metal other than the wiring pattern portion was removed by CMP to form a layer of copper wiring 14.

Next, a dual damascene method for simultaneously forming a via layer and a wiring layer will be described. On the first wiring layer, a SiN film (50 nm) is formed as the diffusion prevention film 13 by plasma CVD using silane and ammonia gas for the purpose of preventing Cu diffusion, and the low dielectric constant film formation of Example 4 is formed. A low dielectric constant film 10 (650 nm) was formed and laminated in the same manner as in Example 4 using the composition for use. A SiN film (50 nm) is formed as a stopper film 7 by plasma CVD using silane and ammonia gas in the wiring layer portion, and the low dielectric constant film forming composition of Example 4 is used. Similarly, a low dielectric constant film 10 (400 nm) was formed thereon. A TEOS-SiO ₂ film was laminated as the cap film 12 (50 nm). The low dielectric constant film 10 is changed to SiO ₂ / low dielectric constant insulating film / SiN / by changing the gas composition by F plasma using CF ₄ / CHF ₃ gas as a raw material with a resist layer having a via pattern formed as a mask. The low dielectric constant insulating film / SiN were processed in this order. Subsequently, using the resist layer provided with the second-layer wiring pattern as a mask, processing was performed by F plasma using CF ₄ / CHF ₃ gas as a raw material. A barrier film 8 (TiN; 50 nm) serving as a diffusion barrier to the Cu insulating layer and a seed layer Cu (50 nm) serving as an electrode during electrolytic plating were formed by sputtering in the via and the wiring groove. Further, after copper (1400 nm) is laminated by electrolytic plating, the metal other than the wiring pattern portion is removed by CMP, and the portions other than the via are removed by chemical mechanical polishing (CMP) in which the copper wiring 14 is formed. Formed. Thus, the above process was repeated to form a three-layer wiring. As described above, in the multilayer wiring in the obtained semiconductor device, the yield of 1 million continuous vias could be 90% or more.

Here, it will be as follows if the preferable aspect of this invention is appended.
(Supplementary Note 1) A composition for forming a low dielectric constant film, comprising at least polysiloxane which is a hydrolysis product of alkoxysilane represented by the following general formula (1) and a radiation-decomposable compound: .
In the general formula (1), X represents at least one of a hydrogen atom, a fluorine atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. R represents at least one of a hydrogen atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. n represents an integer from 0 to 3.
(Additional remark 2) The composition for low dielectric constant film formation of Additional remark 1 whose content of a radiation decomposable compound is 0.1-200 mass parts with respect to 100 mass parts of polysiloxane.
(Supplementary note 3) Supplementary note 1 or 2, wherein the radiolytic compound is selected from at least one of a triarylsulfonium salt represented by the following general formula (2) and a diaryliodonium salt represented by the following general formula (3) 2. A composition for forming a low dielectric constant film according to 1.
In the general formula (2) and the general formula (3), each R ² independently represents at least one of a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, or an alkoxy group. Represents.
(Additional remark 4) The composition for low dielectric constant film formation in any one of Additional remark 1 to 3 containing 2 or more types of radiation-decomposable compounds from which absorption maximum wavelength mutually differs.
(Additional remark 5) The composition for low dielectric constant film formation in any one of Additional remark 1 to 4 containing 2 or more types of radiation-decomposable compounds from which molecular size mutually differs.
(Additional remark 6) The composition for low-dielectric-constant film formation in any one of additional remark 1 to 5 containing the silicone compound which contains hydrocarbon in frame | skeleton.
(Supplementary note 7) Among two or more kinds of absorption maximum wavelengths different from each other, the content ratio of a radiolytic compound having a large absorption maximum wavelength and a radiolytic compound having a small absorption wavelength (radiolytic compound having a large absorption maximum wavelength / The composition for forming a low dielectric constant film according to supplementary note 4, wherein the radiation-decomposable compound having a small absorption wavelength is 1/100 to 100/1.
(Supplementary Note 8) The content ratio of a radiodegradable compound having a large molecular size and a radiodegradable compound having a small molecular size among two types of radiodegradable compounds having different molecular sizes (radiolytic properties having a large molecular size) The composition for forming a low dielectric constant film according to appendix 5, wherein the compound / radiolytic compound having a small molecular size is 1/100 to 100/1.
(Supplementary note 9) The low dielectric constant according to supplementary note 6, wherein the content of the silicone compound containing a hydrocarbon in the skeleton is 0.1 to 200 parts by mass with respect to 100 parts by mass of the polysiloxane. Composition for forming a rate film.
(Additional remark 10) The low dielectric constant characterized by apply | coating the composition for low-dielectric-constant film formation in any one of Additional remark 1 to 9 on a board | substrate, forming a coating film, and irradiating this coating film with a radiation A method for producing a membrane.
(Additional remark 11) The manufacturing method of the low dielectric constant film of Additional remark 10 which heat-processes to a coating film.
(Additional remark 12) The manufacturing method of the low dielectric constant film of Additional remark 11 which heat-processes at 250-300 degreeC.
(Supplementary note 13) The method for producing a low dielectric constant film according to any one of supplementary notes 10 to 12, wherein the radiation is selected from infrared light, visible light, ultraviolet light, X-rays, and an electron beam.
(Additional remark 14) The low dielectric constant in any one of Additional remark 10 to 13 whose light absorbency with respect to the wavelength (The light absorbency in 10 < ^-1 > -10 < ⁶ > Å) of the radiation to irradiate is 1.75 or less. A method for producing a membrane.
(Additional remark 15) The manufacturing method of the low dielectric constant film | membrane in any one of additional remark 10 to 14 which irradiates 2 or more types of radiation.
(Supplementary Note 16) A low dielectric constant film formed by the method for producing a low dielectric constant film according to any one of Supplementary Notes 10 to 15.
(Supplementary note 17) The low dielectric constant film according to supplementary note 16, having a plurality of holes having a diameter of 100 nm or less.
(Supplementary Note 18) A semiconductor device having the low dielectric constant film according to Supplementary Note 18 or 19 as an interlayer insulating film.

FIG. 1 is a schematic explanatory view showing an example of the semiconductor device of the present invention using the low dielectric constant film of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Silicon wafer 2 ... Interelement isolation film 3 ... Side wall insulating film 4 ... Gate electrode 5a ... Source diffusion layer 5b ... Drain diffusion layer 6 ... Interlayer insulating film (phosphorus glass) )
7: Stopper film 8 ... Barrier film 9 ... Conductor plug (W)
10 .... Low dielectric constant film 12 .... Cap film 13 .... Diffusion prevention film

Claims (9)

A low dielectric constant comprising at least a polysiloxane which is a hydrolysis product of an alkoxysilane represented by the following general formula (1) and two or more kinds of radiation-decomposable compounds having different absorption maximum wavelengths. Composition for forming a rate film.
In the general formula (1), X represents at least one of a hydrogen atom, a fluorine atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. R represents at least one of a hydrogen atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. n represents an integer from 0 to 3. Low dielectric constant characterized by containing at least polysiloxane which is a hydrolysis product of alkoxysilane represented by the following general formula (1) and two or more kinds of radiation decomposable compounds having different molecular sizes Film forming composition.
In the general formula (1), X represents at least one of a hydrogen atom, a fluorine atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. R represents at least one of a hydrogen atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. n represents an integer from 0 to 3. It contains polysiloxane which is a hydrolysis product of alkoxysilane represented by the following general formula (1) and at least two or more kinds of radiation-decomposable compounds having different absorption maximum wavelengths and molecular sizes. A composition for forming a low dielectric constant film.
In the general formula (1), X represents at least one of a hydrogen atom, a fluorine atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. R represents at least one of a hydrogen atom, an alkyl group, an aryl group, a vinyl group, and an alicyclic group. n represents an integer from 0 to 3. The low dielectric constant film according to any one of claims 1 to 3, wherein a content of the radiation decomposable compound in the composition for forming a low dielectric constant film is 0.1 to 200 parts by mass with respect to 100 parts by mass of the polysiloxane. Forming composition. The radiodegradable compound is selected from at least one of a triarylsulfonium salt represented by the following general formula (2) and a diaryliodonium salt represented by the following general formula (3). 2. A composition for forming a low dielectric constant film according to 1.
In the general formula (2) and the general formula (3), each R ² independently represents at least one of a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, or an alkoxy group. Represents. The composition for forming a low dielectric constant film according to any one of claims 1 to 5, comprising a silicone compound containing a hydrocarbon in the skeleton. The content ratio of a radiation-decomposable compound having a large absorption maximum wavelength and a radiation-decomposable compound having a small absorption wavelength among two or more types having different absorption maximum wavelengths (radiodegradable compound having a large absorption maximum wavelength / small absorption wavelength) The composition for forming a low dielectric constant film according to claim 1, wherein the radiation-decomposable compound is 1/100 to 100/1. Of the two types of radiolytic compounds having different molecular sizes, the content ratio of the radiolytic compound having a large molecular size and the radiolytic compound having a small molecular size (radiolytic compound having a large molecular size / molecular size) The composition for forming a low dielectric constant film according to claim 2, wherein the radiation decomposable compound) is 1/100 to 100/1. The low dielectric constant film formation according to claim 6, wherein the content of the silicone compound containing a hydrocarbon in the skeleton in the composition for forming a low dielectric constant film is 0.1 to 200 parts by mass with respect to 100 parts by mass of the polysiloxane. Composition.