JP4467215B2 - Method for forming porous insulating film and method for manufacturing semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a porous insulating film having a high mechanical strength and capable of forming a porous insulating film having a low dielectric constant and a method for manufacturing a semiconductor device.
[0002]
[Prior art]
In recent years, with an increase in the degree of integration of semiconductor integrated circuits and an improvement in element density, there is an increasing demand for multilayer semiconductor elements. Along with the high integration of such semiconductor integrated circuits, the problem of wiring delay in which the capacitance between wirings connecting semiconductor elements increases and the signal propagation speed decreases has become apparent.
[0003]
So far, in the generation where the wiring interval of the semiconductor device is 1 μm or more, the influence of the wiring delay on the entire device has not been significant. However, when the wiring interval becomes 1 μm or less as the semiconductor integrated circuit is highly integrated, the influence of the wiring delay on the device speed cannot be ignored. In particular, when a circuit is formed with a wiring interval of 0.5 μm or less in the future, a wiring delay due to a parasitic capacitance between the wirings has a significant influence on the device speed.
[0004]
In general, it is known that the wiring delay T is affected by the wiring resistance R and the capacitance C between the wirings, and is expressed by the following equation.
[0005]
T∝CR
Here, the capacitance C between wirings is expressed by the following equation using the electrode area S, the wiring spacing d, the vacuum dielectric constant ε ₀ , and the relative dielectric constant ε _r of the inter-wiring insulating film.
[0006]
C = ε ₀ ε _r S / d
Therefore, it can be seen that reducing the dielectric constant of the inter-wiring insulating film is an effective means for reducing the wiring delay.
[0007]
Conventionally, in a semiconductor integrated circuit, as the material of the wiring insulating film, and silicon dioxide SiO _2, silicon nitride SiN, phosphosilicate glass (PSG, Phospho Silicate Glass), etc. are used. And the value of the dielectric constant of the silicon oxide film formed by the chemical vapor deposition (CVD) method most used in the semiconductor device is about 4.
[0008]
Furthermore, in order to reduce the dielectric constant of the insulating film, application of an organic polymer such as a fluorine-added silicon oxide film (SiOF film) formed by a CVD method or polyimide as an inter-wiring insulating film has been studied. Further, it has been studied to apply a silica-based porous film whose dielectric constant is reduced by forming a large number of pores in the film to the inter-wiring insulating film.
[0009]
[Problems to be solved by the invention]
However, the SiOF film formed by the CVD method has a dielectric constant of about 3.3 to 3.5, and it is difficult to form a film having a dielectric constant of 3 or less. For this reason, when applied as an inter-wiring insulating film, the capacitance between the wirings could not be sufficiently reduced. In addition, the SiOF film has high hygroscopicity, and the dielectric constant may increase after film formation.
[0010]
On the other hand, organic polymers such as polyimide have a low dielectric constant of about 2-3. However, since organic polymers have difficulty in heat resistance and adhesion, restrictions have been imposed on the semiconductor device manufacturing process.
[0011]
From the background described above, a silica-based porous film is considered promising in order to realize a low dielectric constant required in the future. However, in the case of a silica-based porous film, when the pore volume in the film is increased in order to reduce the dielectric constant, the mechanical strength of the film is extremely lowered. For this reason, there exists a difficulty that it is easy to destroy during processes, such as chemical mechanical polishing (CMP, Chemical Mechanical Polishing). Therefore, from the viewpoint of forming a low dielectric constant insulating film that is indispensable for realizing a high-speed semiconductor device, the present situation is that sufficient characteristics are not obtained even with a silica-based porous film.
[0012]
An object of the present invention is to provide a method for forming a porous insulating film and a method for manufacturing a semiconductor device that can form a porous insulating film having excellent mechanical strength and a low dielectric constant.
[0013]
[Means for Solving the Problems]
The object is to apply on the substrate a solution containing a partial hydrolysis-condensation product of alkoxysilane in which at least some of the end groups are terminated with hydrogen and a pore-forming resin; Drying the solution, forming a film containing the partial hydrolysis-condensation product and the pore-forming resin on the substrate, and desorbing the pore-forming resin from the membrane; A step of forming pores therein, and a step of firing the film in an atmosphere containing water vapor at a concentration of 100 ppm to 10% to promote cross-linking of the partially hydrolyzed condensate in the film. This is achieved by a method for forming a porous insulating film characterized by the following.
[0015]
In the method for forming a porous insulating film, water vapor may be supplied by bubbling to an atmosphere for firing the film.
[0016]
The object is achieved by a method for manufacturing a semiconductor device, comprising the step of forming a porous insulating film on a semiconductor substrate by the method for forming a porous insulating film.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The method for forming a porous insulating film according to the present invention comprises a step of applying a solution containing a partial hydrolysis-condensation product of alkoxysilane having a terminal group terminated with hydrogen and a hole forming resin on a substrate. Drying the solution applied on the substrate to form a film containing the partial hydrolysis-condensation product and the hole forming resin on the substrate; and forming the hole forming resin from the film. A step of forming voids in the film by desorption, and a step of firing the film in an atmosphere containing water vapor to promote cross-linking of the partially hydrolyzed condensate in the film. There is a main feature.
[0018]
An interlayer insulating film such as a wiring layer of a semiconductor device is required to have a low dielectric constant in order to reduce parasitic capacitance between wirings and suppress the occurrence of wiring delay.
[0019]
The porous insulating film realizes a reduction in dielectric constant by forming pores in the film. By increasing the void volume in the film, an insulating film having a lower dielectric constant can be obtained. However, since the mechanical strength of the film decreases as the pore volume increases, the manufacturing process is restricted, such as the difficulty of applying CMP with a large mechanical load. As a result, even with the porous insulating film, it has not been possible to realize a sufficiently low dielectric constant as an insulating film of a semiconductor device.
[0020]
Therefore, in the present invention, a porous insulating film made of a partially hydrolyzed condensate of alkoxysilane is baked in a predetermined atmosphere to promote cross-linking formation in the porous insulating film. Thereby, a porous insulating film having a high mechanical strength and a low dielectric constant can be formed.
[0021]
Hereinafter, a method for forming a porous insulating film according to the present invention will be described in detail. The “substrate” in the present specification includes not only a semiconductor substrate itself such as a silicon substrate but also a semiconductor substrate on which a transistor, a wiring layer, and the like are formed.
[0022]
The porous insulating film material in the method for forming a porous insulating film according to the present invention comprises a diluent containing a partially hydrolyzed condensate of alkoxysilane and a hole forming resin that functions as a desorbing agent. Below, each composition of the porous insulating film material of this invention is explained in full detail.
[0023]
The alkoxysilane is not particularly limited as long as it can be hydrolytically condensed and can be diluted in a solvent after condensation polymerization. For example, tetraalkoxy silane, trialkoxy silane, dialkoxy silane, methyl trialkoxy silane, methyl dialkoxy silane, dimethyl dialkoxy silane and the like can be applied as the composition of the porous insulating film material of the present invention. Further, these copolymers may be applied as the composition of the porous insulating film forming material of the present invention. Such an alkoxysilane undergoes partial hydrolysis and condensation to form a siloxane resin and form an insulating film.
[0024]
As the alkoxysilane of the general formula ^{_{R 1 l R 2 m R 3}} n Si (OR 4) 4-lmn
(Wherein R ¹ , R ² and R ³ represent H or CH ₃ group, at least one of which is H, R ⁴ represents an alkyl group, and l, m and n are 1 represents an integer of 0 to 3 satisfying 1 ≦ 1 + m + n ≦ 3.)
Those indicated by are desirable. By using alkoxysilane having H at the terminal group as described above, an oxidative bridge in the film can be formed as described later, and the mechanical strength of the film can be improved.
[0025]
In addition, about the thing which does not have H in terminal groups, such as a tetraalkoxysilane and a dimethyl dialkoxysilane, it can use as a copolymer with the alkoxysilane which has H in a terminal group.
[0026]
The resin for forming pores is not particularly limited as long as it functions as a desorbing agent for forming pores in a film made of a partially hydrolyzed condensate of alkoxysilane. For example, a novolac resin, an epoxy resin, an acrylic resin, a polyester resin, a polypropylene resin, or the like can be applied as the pore forming resin of the composition of the porous insulating film material of the present invention. In addition, phenol compounds, alicyclic compounds, and high molecular weight compounds of these compounds can also be applied.
[0027]
Moreover, it is preferable that the addition amount of the hole forming resin is 1 to 50 wt% with respect to the siloxane resin made of the partially hydrolyzed condensate of alkoxysilane. This is because if the amount of the resin functioning as a desorbing agent is 1 wt% or less, sufficient holes cannot be formed in the insulating film to obtain the effect of reducing the dielectric constant. Further, if it is 50 wt% or more, the porosity in the insulating film is excessively increased, leading to a decrease in the mechanical strength of the film.
[0028]
The diluting solvent is not particularly limited as long as it can dissolve the siloxane resin and the hole forming resin made of alkoxysilane. For example, cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, octane, decane, propylene glycol, propion glycol monomethyl ether, propion glycol monomethyl ether acetate, propion glycol monopropyl ether, or the like can be used as a diluent solvent.
[0029]
Next, the procedure of the method for forming a porous insulating film according to the present invention will be described in detail.
[0030]
First, the alkoxysilane that is the composition of the porous insulating film described above and the hole forming resin that functions as a desorbing agent are dissolved in a diluting solvent. At this time, an acid such as nitric acid may be added dropwise to the diluent solvent in order to promote hydrolysis and condensation of alkoxysilane.
[0031]
Next, partial hydrolysis condensation of alkoxysilane proceeds for a predetermined reaction time. Thereafter, water generated during the reaction is removed by a dehydrating agent, and alcohol as a by-product is separated and removed from the diluted solvent.
[0032]
Next, this diluted solvent is applied onto the substrate on which the porous insulating film is to be formed, for example, using a spin coat method.
[0033]
Next, the substrate coated with the porous insulating film forming material is annealed at a temperature of 120 ° C. to 300 ° C. In this way, the desorbing agent is removed by solvent drying and heating. Note that the desorbing agent may be desorbed by ultraviolet irradiation. Thus, a large number of pores are formed in the siloxane resin, which is a partially hydrolyzed condensate of alkoxysilane, and a porous insulating film is obtained.
[0034]
Next, the porous insulating film formed over the substrate is subjected to heat treatment at 300 ° C. or higher in an atmosphere containing water vapor. Thereby, it is promoted that the terminal H of the siloxane resin forming the porous insulating film forms an oxidative bridge. By forming oxidative crosslinks in the film, the mechanical strength of the siloxane resin is improved. Thus, a porous insulating film having a low dielectric constant and high mechanical strength can be obtained.
[0035]
The atmosphere in which the heat treatment for promoting the formation of oxidative crosslinking of the siloxane resin is preferably an inert gas such as nitrogen containing about 100 ppm to 10% water vapor. This range of water vapor concentration is due to the following reason. That is, when the water vapor concentration is 100 ppm or less, the oxidative crosslinking effect of the siloxane resin is insufficient, so that the strength of the porous insulating film is lowered. On the other hand, if water vapor is present at a concentration of 10% or more, the siloxane resin is excessively oxidized, and the dielectric constant value of the porous insulating film increases.
[0036]
Therefore, in order to obtain a porous insulating film having a high mechanical strength and a low dielectric constant, the atmosphere for promoting the crosslinking formation by the heat treatment is set to a non-volatile state such as nitrogen containing about 100 ppm to 10% water vapor. It is preferable to use an active gas.
[0037]
For the heat treatment in an atmosphere of an inert gas containing water vapor, for example, a baking apparatus shown in FIG. 1 can be used.
[0038]
As shown in the figure, the firing apparatus has a reaction furnace 12 in which a heat treatment of the substrate 10 coated with the porous insulating film forming material is performed. A boat 14 is provided in the reaction furnace 12 to hold a plurality of substrates 10 coated with a porous insulating film forming material in a state of being arranged in the vertical direction at a predetermined interval. A nozzle 16 for introducing an inert gas containing water vapor into the reaction furnace 12 is provided from the bottom of the reaction furnace 12 in parallel with the arrangement direction of the substrates 10 held by the boat 14. Around the reaction furnace 12, a heater 18 for heating the substrate 10 is disposed.
[0039]
A pipe 20 for supplying an inert gas is connected to one end of the nozzle 16 extending from the bottom of the reaction furnace 10 to the outside. Further, the pipe 20 is connected with a pipe 22 for supplying an inert gas containing water vapor by bubbling. The pipe 22 is provided with a water vapor generating container 24 in which pure water is stored, so that an inert gas containing water vapor can be supplied by bubbling.
[0040]
When performing the heat treatment, an inert gas is supplied from the pipe 20 and the pipe 22, and an inert gas containing water vapor is introduced into the reaction furnace 12 from the nozzle 16. At this time, the water vapor concentration contained in the inert gas introduced into the reaction furnace 12 is controlled by controlling the flow rate of the inert gas from the pipe 22.
[0041]
Next, after the inside of the reaction furnace 12 is filled with an inert gas containing a predetermined concentration of water vapor, the substrate 10 is heated to a predetermined temperature by the heater 18. In this way, the formation of oxidative crosslinking of the siloxane resin, which is a porous insulating film formed on the substrate 10, is promoted.
[0042]
As mentioned above, by firing in an atmosphere containing water vapor and promoting cross-linking formation by oxidation in the porous insulating film, in the porous insulating film as compared with the case where heat treatment is performed only in an inert gas atmosphere The crosslink density of can be greatly increased. As a result, sufficient mechanical strength can be obtained even when a large number of holes having a size of 100 nm or less are formed in the film and the dielectric constant is reduced to, for example, 2.5 or less. .
[0043]
Next, a method for manufacturing a semiconductor device according to the present invention will be described with reference to FIGS. 2 to 5 are process sectional views showing a method for manufacturing a semiconductor device according to the present invention. Here, a case where the porous insulating film obtained by the porous insulating film forming method according to the present invention is applied to an interlayer insulating film of a multilayer wiring of a semiconductor device formed by a damascene method will be described. Note that the manufacturing conditions such as the film thickness and film material in the semiconductor device described below are examples, and the design can be changed as appropriate.
[0044]
First, the porous insulating film 28 having a thickness of 450 nm is formed on the silicon substrate 26 by the porous insulating film forming method according to the present invention. Next, a 50 nm-thickness silicon oxide film 30 is formed on the porous insulating film 28 by CVD using TEOS (TetraEthOxySilane) as a raw material (FIG. 2A).
[0045]
Next, a resist film 32 is formed on the silicon oxide film 30 by photolithography to expose a region where a first-layer wiring pattern is to be formed (FIG. 2B).
[0046]
Next, using the patterned resist film 32 as a mask, the silicon oxide film 30 and the porous insulating film 28 are etched by RIE (Reactive Ion Etching) using CF ₄ / CHF ₃ . In this way, the first-layer wiring pattern-shaped wiring groove 34 is formed (FIG. 2C). After the formation of the wiring trench 34, the resist film 32 is removed.
[0047]
Next, a tantalum nitride film 36 having a thickness of 50 nm and a seed copper film 38 having a thickness of 50 nm are sequentially formed on the entire surface by sputtering. Next, a copper film 40 having a film thickness of 600 nm is formed on the seed copper film 38 by electrolytic plating (FIG. 2D).
[0048]
Next, the copper film 40, the seed copper film 38, and the tantalum nitride film 36 formed on portions other than the wiring trench 34 are removed by CMP. Here, since the porous insulating film 28 formed by the porous insulating film forming method according to the present invention has high mechanical strength, the copper film 40 and the like can be easily removed by CMP. Thus, a first wiring layer made of the copper film 40 embedded in the wiring groove 34 in the wiring pattern is formed (FIG. 3A).
[0049]
Next, the dual damascene method is used to simultaneously form a second wiring layer and vias that connect the first wiring layer and the second wiring layer. First, a silicon nitride film 42 having a thickness of 50 nm is formed on the entire surface of the substrate. Next, a porous insulating film 44 having a thickness of 650 nm is formed by the method for forming a porous insulating film according to the present invention. Next, a silicon nitride film 46 is formed on the porous insulating film 44. Next, a 450 nm-thick porous insulating film 48 is formed on the silicon nitride film 46 by the porous insulating film forming method according to the present invention. Further, a 50 nm thick silicon oxide film 50 is formed on the porous insulating film 48 by a CVD method using TEOS as a raw material (FIG. 3B).
[0050]
Next, a resist film 52 is formed on the silicon oxide film 50 by lithography to expose a region where a via hole is to be formed (FIG. 3C).
[0051]
Next, using the patterned resist film 52 as a mask, the silicon oxide film 50, the porous insulating film 48, the silicon nitride film 46, the porous insulating film 44, and the silicon nitride film 42 are sequentially formed by RIE using CF ₄ / CHF _3. Etch. In this way, a via hole 54 connected to the copper film 40 of the first wiring layer is formed (FIG. 4A). After the formation of the via hole 54, the resist film 52 is removed.
[0052]
Next, a resist film 56 is formed on the entire surface by lithography to expose a region where a second-layer wiring pattern is to be formed (FIG. 4B).
[0053]
Next, using the patterned resist film 56 as a mask, the silicon oxide film 50 and the porous insulating film 48 are sequentially etched by RIE using CF ₄ / CHF ₃ . In this way, the wiring trench 58 in the second layer wiring pattern is formed (FIG. 4C). After the formation of the wiring trench 58, the resist film 56 is removed.
[0054]
Next, a tantalum nitride film 60 having a thickness of 50 nm and a seed copper film 62 having a thickness of 50 nm are sequentially formed on the entire surface by sputtering. Next, a copper film 64 having a thickness of 600 nm is formed on the seed copper film 62 by electrolytic plating (FIG. 5A).
[0055]
Next, the copper film 64, the seed copper film 38, and the tantalum nitride film 60 formed in portions other than the via hole 54 and the wiring groove 58 are removed by CMP. As in the case of forming the first wiring layer, since the porous insulating films 48 and 44 have high mechanical strength, the copper film 64 and the like can be easily removed by CMP. Thus, a second wiring layer made of the copper film 64 embedded in the via hole 54 and the wiring groove 58 in the wiring pattern is formed (FIG. 5B).
[0056]
Thereafter, the above process is repeated according to the structure of the semiconductor device to be manufactured, thereby forming a multilayer wiring.
[0057]
As described above, when the porous insulating film formed by the porous insulating film forming method according to the present invention is applied as an inter-wiring insulating film of a semiconductor device, the inter-wiring capacitance can be reduced, and the wiring delay can be reduced. Can be suppressed. Furthermore, since it has not only a low dielectric constant but also sufficient mechanical strength, the porous insulating film is not broken in the manufacturing process such as CMP, and the reliability of the semiconductor device can be improved.
[0058]
As described above, according to the present invention, the porous insulating film made of a partially hydrolyzed condensate of alkoxysilane is heat-treated in an inert gas atmosphere containing water vapor to promote the formation of oxidative crosslinks in the film. Therefore, a porous insulating film having high mechanical strength and low dielectric constant can be formed.
[0059]
【Example】
[Example 1]
41.6 g (0.2 mol) of triethoxysilane and 39.6 g of methyl isobutyl ketone were charged into a 200 ml reaction vessel, and 16.2 g (0.9 mol) of 400 ppm nitric acid solution was added dropwise over 10 minutes. After completion of the dropwise addition of nitric acid, an aging reaction was performed for 2 hours. Next, 5 g of magnesium sulfate was added to the reaction solution to remove excess water, and then a solvent containing ethanol as a by-product was removed by a rotary evaporator until the reaction solution reached 50 ml. To the reaction solution thus obtained, 1.25 g of adamantane monophenol was added to prepare a coating solution for forming a porous insulating film.
[0060]
Subsequently, the above-mentioned coating liquid for forming a porous insulating film was applied onto a silicon substrate by a spin coating method. Subsequently, the silicon substrate was baked on a hot plate at 250 ° C. for 3 minutes. Next, the silicon substrate was baked at 350 ° C. for 30 minutes in a d nitrogen atmosphere having a water vapor concentration of 5000 ppm. Thus, a porous insulating film having a thickness of 200 nm was formed on the silicon substrate.
[0061]
A 1 mm gold electrode was formed on the porous insulating film formed on the silicon substrate, and capacitance / voltage characteristics were measured to calculate a dielectric constant value. As a result, the dielectric constant value of the porous insulating film was 2.33.
[0062]
Further, a 100-nm-thick silicon nitride film was formed as a cap film on the porous insulating film, and a stud-pull test was performed to measure the mechanical strength of the porous insulating film. As a result, the stud-pull strength of the porous insulating film was 58 MPa.
[0063]
[Comparative Example 1]
A coating liquid for forming a porous insulating film produced by the same method as in Example 1 was applied on a silicon substrate by spin coating. Next, the silicon substrate was baked on a hot plate at 250 ° C. for 3 minutes. Next, baking was performed at 350 ° C. for 30 minutes in a nitrogen atmosphere. Thus, a porous insulating film having a thickness of 200 nm was formed on the silicon substrate.
[0064]
With respect to the porous insulating film, the dielectric constant and mechanical strength were determined in the same manner as in Example 1. As a result, the value of the dielectric constant was 2.28 and the stud-pull strength was 16 MPa.
[0065]
[Comparative Example 2]
A coating liquid for forming a porous insulating film produced by the same method as in Example 1 was applied on a silicon substrate by spin coating. Next, the silicon substrate was baked on a hot plate at 250 ° C. for 3 minutes. Next, firing was performed at 350 ° C. for 30 minutes in a nitrogen atmosphere having an oxygen concentration of 5000 ppm. Thus, a porous insulating film having a thickness of 200 nm was formed on the silicon substrate.
[0066]
With respect to the porous insulating film, the dielectric constant and mechanical strength were determined in the same manner as in Example 1. As a result, the value of the dielectric constant was 2.29 and the stud-pull strength was 49 MPa.
[0067]
The value of the dielectric constant of the porous insulating film can be controlled by changing the porosity in the film by adjusting the addition amount of the releasing agent which is the composition of the material. Therefore, the porous insulating film was formed by changing the value of the dielectric constant by the porous insulating film forming method of Example 1, Comparative Example 1, and Comparative Example 2. Then, a Stud-pull test was performed on the obtained porous insulating film, and a relationship between the dielectric constant and the Stud-pull strength was obtained in each case. FIG. 3 is a graph showing the relationship between the dielectric constant and the Stud-pull strength of the porous insulating films obtained by the porous insulating film forming methods of the examples and comparative examples.
[0068]
As is clear from FIG. 3, the value of the Stud-pull intensity decreased with increasing dielectric constant, that is, with increasing porosity in the film. In particular, in the case of Comparative Example 2, the decrease rate of the Stud-pull intensity with respect to the increase of the dielectric constant was remarkable. On the other hand, in the case of Example 1, the range of change in mechanical strength with respect to the increase in dielectric constant was small overall. Further, in the case of Example 1, the value of the Stud-pull intensity was generally large as compared with the case of Comparative Example 1 and Comparative Example 2.
[0069]
【The invention's effect】
As described above, according to the present invention, a solution containing a partially hydrolyzed condensate of alkoxysilane in which at least some of the end groups are terminated with hydrogen and a pore-forming resin is applied onto the substrate, The applied solution is dried to form a film containing the partial hydrolysis-condensation product and the hole forming resin on the substrate, and the holes are formed in the film by removing the hole forming resin from the film. In addition, since the film is fired in an atmosphere containing water vapor and the cross-linking formation of the partial hydrolysis condensate in the film is promoted, a porous insulating film having excellent mechanical strength and a low dielectric constant can be formed. .
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of the structure of a baking apparatus used in a method for forming a porous insulating film according to the present invention.
FIG. 2 is a process cross-sectional view (part 1) illustrating the method for manufacturing a semiconductor device according to the present invention;
FIG. 3 is a process cross-sectional view (part 2) illustrating the method for manufacturing a semiconductor device according to the present invention;
FIG. 4 is a process cross-sectional view (part 3) illustrating the method for manufacturing a semiconductor device according to the present invention;
FIG. 5 is a process cross-sectional view (part 4) illustrating the method for manufacturing a semiconductor device according to the present invention;
FIG. 6 is a graph showing the relationship between the dielectric constant and mechanical strength of a porous insulating film formed by the method for forming a porous insulating film according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Substrate 12 ... Reaction furnace 14 ... Boat 16 ... Nozzle 18 ... Heater 20 ... Piping 22 ... Piping 24 ... Water vapor generating container 26 ... Silicon substrate 28 ... Porous insulating film 30 ... Silicon oxide film 32 ... Resist film 34 ... Wiring Groove 36 ... Tantalum nitride film 38 ... Seed copper film 40 ... Copper film 42 ... Silicon nitride film 44 ... Porous insulating film 46 ... Silicon nitride film 48 ... Porous insulating film 50 ... Silicon oxide film 52 ... Resist film 54 ... Via hole 56 ... resist film 58 ... wiring trench 60 ... tantalum nitride film 62 ... seed copper film 64 ... copper film

Claims (3)

Applying a solution containing a partially hydrolyzed condensate of alkoxysilane having at least part of the end groups terminated with hydrogen and a pore-forming resin on the substrate;
Drying the solution applied on the substrate, and forming a film containing the partial hydrolysis-condensation product and the pore-forming resin on the substrate;
Forming vacancies in the film by desorbing the pore-forming resin from the film; and
Firing the film in an atmosphere containing water vapor at a concentration of 100 ppm to 10%, and promoting the cross-linking of the partially hydrolyzed condensate in the film. Method. In the method of forming a porous insulating film according to claim 1 Symbol placement,
A method for forming a porous insulating film, wherein water vapor is supplied by bubbling to an atmosphere for firing the film. The method of manufacturing a semiconductor device characterized by having a claim 1 or 2, wherein the porous insulating film forming a porous insulating film on a semiconductor substrate by forming methods.

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