JP3328545B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device having a wiring structure comprising at least one conductive layer with an insulating layer interposed therebetween. The present invention relates to a method of manufacturing a semiconductor device which is reduced in number.

[0002]

2. Description of the Related Art With miniaturization of semiconductor elements, that is, high integration of semiconductor devices, a multilayer wiring structure has been adopted on a semiconductor substrate. As an insulating layer of such a semiconductor device, a material mainly composed of silicon oxide is generally used in order to reduce a parasitic capacitance between wirings.

[0003] Further, as the aspect ratio between wirings tends to be increased due to a reduction in the spacing between wirings due to miniaturization of semiconductor elements, the insulating layer has a large film thickness and has excellent filling properties between wirings. Is required. As a method for forming an insulating layer that satisfies such requirements, a hydrogen silsesquioxane resin is applied on a semiconductor substrate by a spin coating method or the like, and then fired to form an insulating layer mainly composed of silicon dioxide. It has been proposed.

However, in recent semiconductor devices, highly integrated circuits are designed such that the wiring interval is smaller than 0.18 μm. In such a highly integrated circuit, the relative permittivity of the insulating layer is set to less than 2.7. On the other hand, an insulating layer formed of the above-mentioned material mainly composed of silicon dioxide cannot achieve this relative dielectric constant.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a semiconductor device which enables a relative dielectric constant of an insulating layer to be reduced as compared with the prior art.

[0006]

According to the present invention, there is provided a semiconductor device provided with a wiring structure comprising at least one conductive layer on a semiconductor substrate via an insulating layer composed mainly of silicon dioxide. The density of the insulating layer is reduced, and the relative dielectric constant of the insulating layer is regulated to less than 2.7.

In other words, a method of manufacturing a semiconductor device according to the present invention that achieves the above object provides a method for manufacturing a semiconductor device, comprising the steps of:
In a method of manufacturing a semiconductor device provided with a wiring structure comprising a conductive layer, a precursor of silicon dioxide, inorganic and / or
Or from the following compounds in a solution of organic resin dissolved in a solvent
Apply the solution with the selected additive on the semiconductor substrate,
After the resin is heated and cured to form an insulating layer, the gas is generated by the additive in the insulating layer after the start of the curing to reduce the density of the insulating layer, and after the gas is generated. It is characterized by performing annealing. Compound: amylbenzene, iso
Propylbenzene, 1,2-diethylbenzene, 1,3
-Diethylbenzene, 1,4-diethylbenzene, cyclone
Rohexylbenzene, dipentene, 2,6-dimethylna
Phthalene, p-cymene, show brain oil, solvent naph
Sa, cis-decalin, trans-decalin, deca
, Tetralin, turpentine, kerosene, dodecane, dodeci
Benzene, biphenyl, cyclohexylbenzene,
Setofenone, isophorone, holon, methylcyclohexene
Sanone, methyl-n-heptyl ketone, benzyl acetate,
γ-butyrolactone, dibutyl oxalate , 2-ethyl acetate
Luhexyl, ethyl benzoate, benzyl formate, N-methyl
Rupyrrolidone, cyclohexylbenzene, 1-decano
, 1-undecanol, 1-dodecanol, benzyl
Alcohol, 1,3-propenediol, 1,4-buta
Diol, 1,5-pentanediol, glycerin,
Xylenols, oxalates, oxalate diethic
Dibutyl oxalate, dipentyl oxalate, ditartrate
Butyl, dimethyl phthalate, diethyl phthalate, ethyl
Glycol diester, benzyl cellosolve, phenyl
Lucerosolve

As described above, an additive selected from the above compounds is added to a solution obtained by dissolving an inorganic and / or organic resin in a solvent.
Applying the obtained solution to a semiconductor substrate, solidifying the resin to form an insulating layer, and generating gas by the additive in the insulating layer after the start of the curing to reduce the density of the insulating layer. This makes it possible to make the relative permittivity of the insulating layer less than 2.7. Therefore, in a semiconductor device in which a wiring structure including at least one conductive layer is provided on a semiconductor substrate with an insulating layer interposed therebetween, even in a highly integrated circuit in which a wiring interval is narrower than 0.18 μm, a distance between wirings is reduced. The parasitic capacitance can be sufficiently reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 illustrates a manufacturing process of a semiconductor device according to an embodiment of the present invention. First, as shown in FIG. 1A, a semiconductor substrate (silicon wafer) 1 having a semiconductor element (not shown) formed on a surface thereof
A BPSG film or the like is deposited on the entire surface of the substrate and reflowed to form a base insulating layer 2. Next, a conductive layer is formed by sputtering a metal such as aluminum on the base insulating layer 2, and is patterned by a known method to form a lower wiring 3.
a, 3b and 3c are formed.

Next, as shown in FIG. 1B, a solution obtained by dissolving an inorganic and / or organic resin in a solvent is applied to the semiconductor substrate 1.
Is applied over the entire surface by spin coating or the like, and then heat-treated to cure the resin to form the insulating layer 4.
At this time, a gas is generated in the insulating layer 4 during or after the curing of the resin, and the generation of the gas lowers the density of the insulating layer 4. This reduction in density occurs because the insulating layer 4 becomes porous, or the insulating layer 4
Is caused by the increase in free space.

Next, as shown in FIG. 1C, the lower layer wirings 3a and 3c are respectively etched by masking with a photoresist and selectively etching the insulating layer 4 on the lower wirings 3a and 3c, for example. After the through hole 5 is reached, a conductive layer is formed by sputtering a metal such as aluminum on the entire surface, and this is etched back until the insulating layer 4 is exposed by plasma etching. The interlayer wiring is left.

Next, as shown in FIG. 1D, upper wirings 6a and 6b and an insulating layer 7 are formed on the etched back surface in the same manner as the lower wirings 3a to 3c and the insulating layer 4, respectively. . Thus, on the semiconductor substrate 1,
A multilayer wiring structure including lower wirings 3a to 3c and upper wirings 6a and 6b is formed, and these wirings are electrically insulated by the base insulating layer 2 and the interlayer insulating layers 4 and 7. The insulating layer 4 reduced in density by the above-described manufacturing method has a relative dielectric constant of 2.
It is possible to make it less than 7.

In the present invention, the relative dielectric constant of the insulating layer is set to 2.
In order to reduce the density to less than 7, it is necessary that the density of the insulating layer is low and the porosity or free space is large. However, in forming such a porosity, film strength, dielectric breakdown, adhesion,
It is necessary not to adversely affect hygroscopicity. Therefore, it is preferable to use a hydrogen silsesquioxane resin, which is one of the precursors of silicon dioxide, as the resin of the insulating layer.

The hydrogen silsesquioxane resin is a compound represented by the general formula (HSiO _3/2 ) _n (n: an integer). Since the molecular weight of the hydrogen silsesquioxane resin is larger than the molecular weight of polysilicic acids and the like, the SOG film using the hydrogen silsesquioxane resin as a starting material has a different inorganic S type.
It can be formed thicker than the OG film. In addition, the SOG film using hydrogen silsesquioxane resin as a starting material
Since it has a property of glass transition from about 00 ° C., the curing temperature can be lowered, and Si—
Since it has a network structure formed by siloxane bonds terminated by H bonds, it has better water resistance than other inorganic SOG films.

The solvent used for dissolving the resin such as hydrogen silsesquioxane resin is not particularly limited. Examples of the solvent include aromatic solvents such as toluene and xylene;
Aliphatic solvents such as hexane, heptane and oxane, methyl ethyl ketone, methyl isobutyl ketone (MIBK)
Ketone solvents such as butyl acetate, isoamyl acetate and the like, and chain solvents such as 1,1,1,3,3,3-hexamethyldisiloxane and 1,1,3,3-tetramethyldisiloxane. Siloxane, 1,1,3,3,5,5
7,7-octamethyltetracyclosiloxane, 1,
Examples thereof include silicone solvents such as cyclic siloxanes such as 3,5,7-tetramethyltetracyclosiloxane, silane compounds such as tetramethylsilane and dimethyldiethylsilane, and a mixture of two or more of the above solvents. Can also.

In the solution in which the inorganic or organic resin is dissolved, an additive for generating gas, a dispersion stabilizer for uniformly dispersing bubbles due to gas generation, a curing accelerator for accelerating a curing reaction, and the like. May be contained in advance. Alternatively, after applying the resin solution on the semiconductor substrate, the solvent may be removed, and the step on the semiconductor substrate may be buried by melting the resin, and the unevenness of the insulating layer may be flattened.
In this case, it is preferable to use a resin having a melting point or a softening point.

Examples of the method of solidifying the resin include a method of solidifying by scattering a solvent at room temperature or under heating, and a method of irradiating a high energy ray such as an ultraviolet ray or an electron beam to solidify the resin. A method of solidifying under heating is preferred. In the method of solidifying under heating, the resin on the semiconductor substrate is cured by being heated by an arbitrary heat source under an arbitrary atmosphere. The heat source is not particularly limited, but a furnace, an oven, a hot plate and the like can be used. Although the atmosphere of the curing reaction is not particularly limited, the curing reaction may be performed in a special atmosphere such as steam, ammonia, nitrogen monoxide, ozone, or the like, in addition to a nitrogen atmosphere or an oxygen atmosphere. In addition, as a crosslinking mode in the curing reaction, crosslinking by a substituent (functional group) such as a silicon atom-bonded hydrogen atom or a vinyl group, or a functional alkoxy bond or silanol bond as found in a conventional inorganic or organic SOG is used. And the like.

The resin is cured by being heated while containing at least a solvent and additives. Then, gas is generated by the additive after the start of curing of the resin .
This is because if the resin is uncured during the gas generation process, the resin is dissolved, so that an insulating layer having a desired thickness cannot be obtained or a crack occurs in the insulating layer.

In order to control the generation of gas so as to occur after the start of curing of the resin, the starting temperature of gas generation or the setting of the starting temperature of curing of the resin may be set low so that the solvent or the solvent at the starting temperature of curing can be controlled. What is necessary is just to make an additive chemically stable. Further, it is preferable that the generation of the gas occurs after gentle curing and before complete curing. By causing the gas to be generated before the complete curing, the insulating layer can be effectively made porous.

The generation of the above gas may be performed under reduced pressure. By performing gas generation under reduced pressure, gas generation can be promoted. The gas may be generated by heating or by applying a microwave such as an ultrasonic wave or an electromagnetic wave. By performing generation of gas by application of microwaves, it becomes possible to lower the heat treatment temperature in the entire manufacturing process. After the generation of gas, annealing may be performed by heating and maintaining the semiconductor substrate at a constant temperature to remove molding distortion of the insulating layer.

The additives above mentioned contributes to porosity of the insulating layer causes a generation of a gas. It is preferred that this additive has a different boiling point or vapor pressure curve from that of the solvent, or that it has a different affinity for inorganic and / or organic resins than the solvent. The additive preferably has good compatibility and dispersibility in a resin and a solvent.
Further, the additive may be used by mixing a single component of liquid or solid or a mixture of multiple components, and may contain an auxiliary such as a dispersion stabilizer or a surfactant as needed.

Examples of the method for generating the additive gas include volatilization (simple vaporization) , sublimation, and vaporization of a solid after liquefaction. In particular, an additive that causes vaporization is preferable because it does not remain in the system after gas generation and does not adversely affect the semiconductor device. The temperature at which gas is generated from the additive is in the range of 0 to 800 ° C., and preferably 25 to 400 ° C., because it is necessary to adapt to the process of forming the insulating layer. Further, it is preferable that most of the solvent evaporates immediately after being applied to the substrate and then gas generation from the additive occurs. Therefore, the starting temperature of gas generation from the additive is preferably higher than the boiling point of the solvent .

As such an additive, approximately 200 ° C.
Organic solvents having the above boiling points, hydrocarbons, halogenated hydrocarbons, alcohols, ethers / acetals, ketones /
Aldehydes, esters, polyhydric alcohols, carboxylic acids, anhydrides, phenols, nitrogen-containing compounds, sulfur-containing compounds, fluorine compounds, inorganic solvents, silicones and the like can be used.

Examples of the hydrocarbon include amylbenzene (boiling point 202 ° C.), isopropylbenzene (boiling point 152 ° C.),
1,2-diethylbenzene (boiling point 183 ° C.), 1,3-
Diethylbenzene (boiling point 181 ° C), 1,4-diethylbenzene (boiling point 184 ° C), cyclohexylbenzene (boiling point 239 ° C), dipentene (boiling point 177 ° C), 2,
6-dimethylnaphthalene (boiling point 262 ° C), p-cymene (boiling point 177 ° C), show brain oil (boiling point 160 to 185)
° C), solvent naphtha (boiling point 110-200 ° C), c
is-decalin (boiling point 196 ° C), trans-decalin (boiling point 187 ° C), decane (boiling point 174 ° C), tetralin (boiling point 207 ° C), turpentine oil (boiling point 153 to 17)
5 ° C.), kerosene (boiling point two hundred to two hundred and forty-five ° C.), dodecane (boiling point 216 ° C.), dodecylbenzene, branched dodecylbenzene, cyclohexylbenzene, diphenyl Eniru and the like.

As ketones and aldehydes, acetophenone (boiling point: 201.7 ° C.), isophorone (boiling point: 215.0 ° C.)
3 ° C.), holon (boiling point 198 to 199 ° C.), methylcyclohexanone (boiling point 169.0 to 170.5 ° C.), methyl-n-heptylketone (boiling point 195.3 ° C.), and the like. As the ester, diethyl phthalate (boiling point 2
96.1 ° C.), benzyl acetate (boiling point 215.5 ° C.), γ
-Butyrolactone (boiling point 204 ° C), dibutyl oxalate (boiling point 240 ° C), 2-ethylhexyl acetate (boiling point 19
8.6 ° C.), ethyl benzoate (boiling point 213.2 ° C.), benzyl formate (boiling point 203 ° C.), and the like. As the nitrogen-containing compound, N-methylpyrrolidone (boiling point: 202 ° C.)
And the like .

The solid additives include cyclohexylbenzene (boiling point 240.12 ° C.), 1-decanol (boiling point 231 ° C.), 1-undecanol (boiling point 243 ° C.),
-Dodecanol (boiling point 259 ° C), benzyl alcohol (boiling point 205.45 ° C), 1,3-propenediol (boiling point 214 ° C), 1,4-butanediol (boiling point 22
9.2 ° C.), 1,5-pentanediol (bp 242.
4 ° C), glycerin (boiling point 290 ° C), xylenols (boiling point 201 to 226 ° C), oxalic acid ester, diethyl oxalate (boiling point 185.4 ° C), dibutyl oxalate (boiling point 245.5 ° C), dipentyl oxalate (Boiling point 15
1.4 ° C) , dibutyl tartrate (boiling point 312 ° C), dimethyl phthalate (boiling point 282 ° C), diethyl phthalate (boiling point 295 ° C), ethylene glycol diester, benzyl cellosolve (boiling point 256 ° C), phenyl cellosolve (boiling point 244.4 ° C). 7 ° C.).

Examples of the curing accelerator to be contained in the tree butter solution, it is possible to use a compound containing platinum, such as chloroplatinic acid hexahydrate. The compound containing platinum promotes the curing of the resin by dehydrogenation, so that the curing temperature can be lowered.

[0028]

EXAMPLES The following semiconductor device was actually manufactured by the manufacturing method of the present invention, and the conversion property of the insulating layer to silica and the relative dielectric constant were measured. The conversion to silica was determined by Fourier transform infrared absorption spectroscopy by measuring the percentage (%) of the Si—H bonds remaining in the insulating layer immediately after spin coating as 100%. The relative dielectric constant of a sample formed on a silicon wafer was measured at a temperature of 25 ° C. and 1 MHz. The measurement was performed using an impedance analyzer to measure the capacitance between wirings by a sandwich method in which aluminum electrodes were formed.

Example 1 Hydrogen silsesquioxane resin (number average molecular weight 1540,
Component 4 having a weight average molecular weight of 7705 and a molecular weight of 1500 or less
(1%, softening point 90 ° C.).
830, a weight average molecular weight of 11,200 and a softening point of 180 ° C. were obtained. This fraction was dissolved in methyl isobutyl ketone to prepare a solution having a solid content of 18% by weight. To this solution was added 1% by weight of dodecylbenzene based on the weight of the solution and 100% by weight of pp based on the weight of the fraction.
m of chloroplatinic acid hexahydrate was added.

From this solution, an interlayer insulating layer of a semiconductor device having an aluminum multilayer wiring structure (a wiring pattern having a step height of 0.5 μm, a step width and a step interval of 0.18 μm each) was formed on a silicon wafer. Specifically, the base step is C
After coating with a VD film, the above solution was placed on a silicon wafer,
Spin coating is performed for 3 seconds at a pre-rotation speed of 500 rpm and then for 10 seconds at a main rotation at a rotation speed of 5000 rpm. After sufficiently evaporating the solvent, the solution is allowed to stand at room temperature for 10 minutes. Was formed. This wafer was baked at 250 ° C. for 1 hour in a quartz furnace under an air stream, taken out, and left at room temperature for 10 minutes. In this state, the solubility of the insulating layer in methyl isobutyl ketone was lower than immediately after spin coating.

Next, the above-described wafer was placed in a quartz furnace at 400 ° C. for 1 hour under a nitrogen stream containing 10 ppm of oxygen.
After annealing for a period of time, it was taken out and left at room temperature for 10 minutes. The ratio of Si—H bonds remaining in the insulating layer formed on the wafer was 74%, indicating that the hydrogen silsesquioxane resin was converted to silica. Also,
No abnormality such as generation of cracks was observed in the converted insulating layer.

Further, after a CVD film was formed on the insulating layer, a multilayer wiring structure of a via hole contact type was formed. The relative permittivity of the insulating layer of this semiconductor device was 2.5, and no abnormality was found in the electrical characteristics. Example 2 The fraction of Example 1 was dissolved in methyl isobutyl ketone to prepare a solution having a solid content of 18% by weight. To this solution was added 10% by weight of dodecylbenzene based on the weight of the solution and 100% by weight of chloroplatinic acid hexahydrate based on the weight of the fraction.

From this solution, an interlayer insulating layer of a semiconductor device having an aluminum multilayer wiring structure (wiring pattern having a step height of 0.5 μm, a step width and a step interval of 0.18 μm each) was formed on a silicon wafer. Specifically, the base step is C
After coating with a VD film, the above solution was placed on a silicon wafer,
Spin coating is performed for 3 seconds in a pre-rotation at a rotation speed of 500 rpm, and then for 10 seconds in a main rotation at a rotation speed of 5000 rpm. After sufficiently evaporating the solvent, the solution is allowed to stand at room temperature for 10 minutes. Was formed. This wafer was baked at 250 ° C. for 1 hour in a quartz furnace under an air stream, taken out, and left at room temperature for 10 minutes. In this state, the solubility of the insulating layer in methyl isobutyl ketone was lower than immediately after spin coating.

Next, the above-mentioned wafer was placed in a quartz furnace at 400 ° C. for 1 hour under a nitrogen stream containing 10 ppm of oxygen.
After annealing for a period of time, it was taken out and left at room temperature for 10 minutes. The proportion of Si—H bonds remaining in the insulating layer formed on the wafer was 79%, indicating that the hydrogen silsesquioxane resin was converted to silica. Also,
No abnormality such as generation of cracks was observed in the converted insulating layer.

Further, after a CVD film was formed on the insulating layer, a multilayer wiring structure of a via hole contact type was formed. The relative dielectric constant of the insulating layer of this semiconductor device was 2.4, and no abnormality was found in the electrical characteristics. Example 3 The fraction of Example 1 was dissolved in methyl isobutyl ketone to prepare a solution having a solid content of 20% by weight. To this solution was added 10% by weight of dodecylbenzene based on the weight of the solution and 100% by weight of chloroplatinic acid hexahydrate based on the weight of the fraction.

From this solution, an interlayer insulating layer of a semiconductor device having an aluminum multilayer wiring structure (a wiring pattern having a step height of 1.0 μm, a step width and a step interval of 0.18 μm each) was formed on a silicon wafer. Specifically, the base step is C
After coating with a VD film, the above solution was placed on a silicon wafer,
Spin coating is performed for 3 seconds at a pre-rotation speed of 500 rpm and then for 10 seconds at a main rotation at a rotation speed of 4500 rpm. After sufficiently evaporating the solvent, the solution is allowed to stand at room temperature for 10 minutes. Was formed. This wafer was baked at 250 ° C. for 1 hour in a quartz furnace under an air stream, taken out, and left at room temperature for 10 minutes. In this state, the solubility of the insulating layer in methyl isobutyl ketone was lower than immediately after spin coating.

Next, the above-described wafer was placed in a quartz furnace at 400 ° C. for 1 hour under a nitrogen stream containing 10 ppm of oxygen.
After annealing for a period of time, it was taken out and left at room temperature for 10 minutes. The proportion of Si—H bonds remaining in the insulating layer formed on the wafer was 79%, indicating that the hydrogen silsesquioxane resin was converted to silica. Also,
No abnormality such as generation of cracks was observed in the converted insulating layer.

Further, after a CVD film was formed on the insulating layer, a multilayer wiring structure of a via hole contact type was formed. The relative dielectric constant of the insulating layer of this semiconductor device was 2.4, and no abnormality was found in the electrical characteristics. Example 4 The fraction of Example 1 was dissolved in methyl isobutyl ketone to prepare a solution having a solid content of 18% by weight. To this solution was added 10% by weight of diethyl phthalate based on the weight of the solution and 100% by weight of chloroplatinic acid hexahydrate based on the weight of the fraction.

From this solution, an interlayer insulating layer of a semiconductor device having an aluminum multilayer wiring structure (wiring pattern having a step height of 0.5 μm, a step width and a step interval of 0.18 μm each) was formed on a silicon wafer. Specifically, the base step is C
After coating with a VD film, the above solution was placed on a silicon wafer,
Spin coating is performed for 3 seconds at a pre-rotation speed of 500 rpm, and then for 10 seconds at a main rotation at a rotation speed of 5000 rpm. After sufficiently evaporating the solvent, the solution is allowed to stand at room temperature for 10 minutes. Was formed. This wafer was baked at 250 ° C. for 1 hour in a quartz furnace under an air stream, taken out, and left at room temperature for 10 minutes. In this state, the solubility of the insulating layer in methyl isobutyl ketone was lower than immediately after spin coating.

Next, the above-mentioned wafer was placed in a quartz furnace at 400 ° C. for 1 hour under a nitrogen stream containing 10 ppm of oxygen.
After annealing for a period of time, it was taken out and left at room temperature for 10 minutes. The ratio of Si—H bonds remaining in the insulating layer formed on this wafer was 78%, indicating that the hydrogen silsesquioxane resin was converted to silica. Also,
No abnormality such as generation of cracks was observed in the converted insulating layer.

Further, after forming a CVD film on the insulating layer, a multilayer wiring structure of a via hole contact type was formed. The relative dielectric constant of the insulating layer of this semiconductor device was 2.4, and no abnormality was found in the electrical characteristics. Example 5 The fraction of Example 1 was dissolved in methyl isobutyl ketone to prepare a solution having a solid content of 18% by weight. To this solution was added 10% by weight of biphenyl based on the solution weight and 100% by weight of chloroplatinic acid based on the weight of the fraction.
Hexahydrate was added.

From this solution, an interlayer insulating layer of a semiconductor device having an aluminum multilayer wiring structure (a wiring pattern having a step height of 0.5 μm, a step width and a step interval of 0.18 μm each) was formed on a silicon wafer. Specifically, the base step is C
After coating with a VD film, the above solution was placed on a silicon wafer,
Spin coating is performed for 3 seconds at a pre-rotation speed of 500 rpm and then for 10 seconds at a main rotation at a rotation speed of 5000 rpm. After sufficiently evaporating the solvent, the solution is allowed to stand at room temperature for 10 minutes. Was formed. This wafer was baked at 250 ° C. for 1 hour in a quartz furnace under an air stream, taken out, and left at room temperature for 10 minutes. In this state, the solubility of the insulating layer in methyl isobutyl ketone was lower than immediately after spin coating.

Next, the above-mentioned wafer was placed in a quartz furnace at 400 ° C. for 1 hour under a nitrogen stream containing 10 ppm of oxygen.
After annealing for a period of time, it was taken out and left at room temperature for 10 minutes. The ratio of Si—H bonds remaining in the insulating layer formed on this wafer was 78%, indicating that the hydrogen silsesquioxane resin was converted to silica. Also,
No abnormality such as generation of cracks was observed in the converted insulating layer.

Further, after a CVD film was formed on the insulating layer, a multilayer wiring structure of a via-hole contact type was formed. The relative dielectric constant of the insulating layer of this semiconductor device was 2.4, and no abnormality was found in the electrical characteristics. Example 6 Hydrogen silsesquioxane resin (number average molecular weight 1540,
(Weight average molecular weight 7705, softening point 90 ° C) was fractionated to obtain a fraction having a number average molecular weight 743, a weight average molecular weight 1613 and a softening point 25 ° C. This fraction was dissolved in a mixed solvent of hexamethyldisiloxane / octamethyltrisiloxane (30/70% by weight) to obtain a solid content of 2%.
A 5% by weight solution was prepared. To this solution was added 10% by weight of dodecylbenzene based on the weight of the solution and 100% by weight of chloroplatinic acid hexahydrate based on the weight of the fraction.

From this solution, an interlayer insulating layer of a semiconductor device having an aluminum multilayer wiring structure (a wiring pattern having a step height of 0.5 μm, a step width and a step interval of 0.18 μm each) was formed on a silicon wafer. Specifically, the base step is C
After coating with a VD film, the above solution was placed on a silicon wafer,
Spin coating is performed for 3 seconds at a pre-rotation speed of 500 rpm, and then for 10 seconds at a main rotation at a rotation speed of 3000 rpm. After sufficiently evaporating the solvent, the solution is allowed to stand at room temperature for 10 minutes. Was formed. This wafer was baked at 250 ° C. for 1 hour in a quartz furnace under an air stream, taken out, and left at room temperature for 10 minutes. In this state, the solubility of the insulating layer in methyl isobutyl ketone was lower than immediately after spin coating.

Next, the above-mentioned wafer was placed in a quartz furnace at 400 ° C. for 1 hour under a nitrogen stream containing 10 ppm of oxygen.
After annealing for a period of time, it was taken out and left at room temperature for 10 minutes. The ratio of Si—H bonds remaining in the insulating layer formed on the wafer was 77%, indicating that the hydrogen silsesquioxane resin was converted to silica. Also,
No abnormality such as generation of cracks was observed in the converted insulating layer.

Further, after a CVD film was formed on this insulating layer, a multilayer wiring structure of a via hole contact type was formed. The relative dielectric constant of the insulating layer of this semiconductor device was 2.2, and no abnormality was found in the electrical characteristics. Example 7 An organic spin-on glass (OCD-TYPE7, manufactured by Tokyo Applied Chemical Industry Co., Ltd.), which is a precursor of silicon dioxide,
10% by weight of dodecylbenzene was added.

From this solution, an interlayer insulating layer of a semiconductor device having an aluminum multilayer wiring structure (a wiring pattern having a step height of 0.5 μm, a step width and a step interval of 0.18 μm each) was formed on a silicon wafer. Specifically, the base step is C
After coating with a VD film, the above solution was placed on a silicon wafer,
Spin coating is performed for 3 seconds in a pre-rotation at a rotation speed of 500 rpm, and then for 10 seconds in a main rotation at a rotation speed of 5000 rpm. After sufficiently evaporating the solvent, the solution is allowed to stand at room temperature for 10 minutes. Was formed. This wafer was baked at 250 ° C. for 1 hour in a quartz furnace under an air stream, taken out, and left at room temperature for 10 minutes. In this state, the solubility of the insulating layer in methyl isobutyl ketone was lower than immediately after spin coating.

Next, the above-described wafer was placed in a quartz furnace at 400 ° C. for 1 hour under a nitrogen stream containing 10 ppm of oxygen.
After annealing for a period of time, it was taken out and allowed to stand at room temperature for 10 minutes, indicating that it had been converted to silica. Further, no abnormality such as generation of cracks was observed in the converted insulating layer. Further, after forming a CVD film on the insulating layer, a multilayer wiring structure of a via hole contact type was formed. The relative dielectric constant of the insulating layer of this semiconductor device was 2.6, and no abnormality was found in the electrical characteristics.

Comparative Example 1 The fraction of Example 1 was dissolved in methyl isobutyl ketone to prepare a solution having a solid content of 18% by weight. From this solution, an interlayer insulating layer of a semiconductor device having an aluminum multilayer wiring structure (wiring pattern having a step height of 0.5 μm, a step width and a step interval of 0.18 μm each) was formed on a silicon wafer. Specifically, after the base step is covered with a CVD film, the solution is spin-coated on a silicon wafer at a pre-rotation speed of 500 rpm for 3 seconds, and then at a main rotation speed of 5000 rpm for 10 seconds. After the solvent was sufficiently evaporated, the mixture was allowed to stand at room temperature for 10 minutes.
A film thickness of 5 ° was formed. The wafer was placed in a quartz furnace at 400 ° C. for 1 hour under a nitrogen stream containing 10 ppm of oxygen.
After annealing for a period of time, it was taken out and left at room temperature for 10 minutes. The ratio of Si—H bonds remaining in the insulating layer formed on the wafer was 75%, indicating that the hydrogen silsesquioxane resin was converted to silica. Also,
No abnormality such as generation of cracks was observed in the converted insulating layer.

Further, after a CVD film was formed on the insulating layer, a multilayer wiring structure of a via-hole contact type was formed. The relative dielectric constant of the insulating layer of this semiconductor device was 2.8, and no abnormality was found in the electrical characteristics. Comparative Example 2 The fraction of Example 1 was dissolved in methyl isobutyl ketone to prepare a solution having a solid content of 20% by weight.

From this solution, an interlayer insulating layer of a semiconductor device having an aluminum multilayer wiring structure (a wiring pattern having a step height of 1.0 μm, a step width and a step interval of 0.18 μm each) was formed on a silicon wafer. Specifically, the base step is C
After coating with a VD film, the above solution was placed on a silicon wafer,
Spin coating is performed for 3 seconds at a pre-rotation speed of 500 rpm and then for 10 seconds at a main rotation at a rotation speed of 4500 rpm. After sufficiently evaporating the solvent, the solution is allowed to stand at room temperature for 10 minutes. Was formed. The wafer was annealed in a quartz furnace at 400 ° C. for 1 hour under a nitrogen stream containing 10 ppm of oxygen, and then taken out and left at room temperature for 10 minutes. The percentage of Si—H bonds remaining in the insulating layer formed on this wafer is 75%
It was found that the hydrogen silsesquioxane resin was converted to silica. Further, the thickness of the converted insulating layer was significantly reduced, and cracks were observed.

Further, after a CVD film was formed on this insulating layer, a multilayer wiring structure of a via-hole contact type was formed. The relative dielectric constant of the insulating layer of this semiconductor device was 2.8, and a poor electrical contact was observed in a part of the device.

[0054]

As described above, according to the present invention, a solution in which an inorganic and / or organic resin is dissolved is applied on a semiconductor substrate, and the resin is solidified to form an insulating layer. By lowering the density of the insulating layer by generating gas in the insulating layer, the relative dielectric constant of the insulating layer can be reduced to less than 2.7. In a semiconductor device provided with a wiring structure composed of at least one conductive layer, the wiring interval is 0.18.
Even in a highly integrated circuit smaller than μm, the parasitic capacitance between wirings can be sufficiently reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing each step of a method for manufacturing a semiconductor device according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 semiconductor substrate (silicon wafer) 2 base insulating layer (BPSG film) 3a, 3b, 3c lower layer wiring 4, 7 interlayer insulating layer 5 through hole 6a, 6b upper layer wiring

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Motoki Sasaki 2-2 Chikusa Beach, Ichihara City, Chiba Prefecture Toray Dow Corning Silicone Co., Ltd. Research and Development Headquarters (72) Inventor Akihiko Kobayashi Chikatsu Beach, Ichihara City, Chiba Prefecture No.2 Toray Dow Corning Silicone Co., Ltd. Research and Development Headquarters (72) Inventor Katsutoshi Mine 2-2 Toray Dow Corning Silicone Co., Ltd. Research and Development Headquarters (56) References JP-A-6-283864 (JP, A) JP-A-8-250490 (JP, A) JP-A-10-92804 (JP, A) JP-A-9-298241 (JP, A) JP-A-8 −330 300 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/3205 H01L 21/321 H01L 21/3213 H01L 21/768 H01L 21/31 H01L 21/312-21 / 314

Claims (6)

(57) [Claims] 1. A method for manufacturing a semiconductor device having a wiring structure comprising at least one conductive layer provided on a semiconductor substrate via an insulating layer composed mainly of silicon dioxide, wherein a precursor of silicon dioxide is provided. Selected from the following compounds in a solution of an inorganic and / or organic resin dissolved in a solvent.
A solution containing the added additive is applied on a semiconductor substrate, and the resin is heated and cured to form an insulating layer, and after the curing starts , a gas is generated by the additive in the insulating layer. A method for manufacturing a semiconductor device, comprising: lowering the density of the insulating layer, and performing annealing after generating the gas. Compound: Amylbenze
, Isopropylbenzene, 1,2-diethylbenzene
1,3-diethylbenzene, 1,4-diethylbenzene
Zen, cyclohexylbenzene, dipentene, 2,6-
Dimethylnaphthalene, p-cymene, show brain oil, sorbet
Tonaphtha, cis-decalin, trans-decalin
, Decane, tetralin, turpentine, kerosene, dodeca
, Dodecylbenzene, biphenyl, cyclohexylbe
Benzene, acetophenone, isophorone, phorone, methyl
Cyclohexanone, methyl-n-heptyl ketone, acetic acid
Benzyl, γ-butyrolactone, dibutyl oxalate, vinegar
2-ethylhexyl acid, ethyl benzoate, benzyl formate
, N-methylpyrrolidone, cyclohexylbenzene,
1-decanol, 1-undecanol, 1-dodecano
Benzyl alcohol, 1,3-propenediol,
1,4-butanediol, 1,5-pentanediol,
Glycerin, xylenols, oxalates,
Diethyl oxalate, dibutyl oxalate, dipentyl oxalate
Dibutyl tartrate, dimethyl phthalate, diele phthalate
Chill, ethylene glycol diester, benzyl celloso
Lube, phenyl cellosolve 2. After the application to the semiconductor substrate, it is cured.
2. The method of manufacturing a semiconductor device according to claim 1, wherein said resin is melted to planarize said insulating layer. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the resin is mainly composed of a hydrogen silsesquioxane resin. 4. A method of manufacturing a semiconductor device according to any one of claims 1 to 3 so as to regulate the relative permittivity of the insulating layer to less than 2.7. 5. A method of manufacturing a semiconductor device according to generation of the gas in any one of claims 1 to 4 was performed under reduced pressure. 6. A method of manufacturing a semiconductor device according to any one of claims 1 to 5 so as to contain a compound containing platinum as the curing accelerator to the solution.