JPH104087A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

(57) Abstract: Provided is a semiconductor device having an insulating film having a low dielectric constant and excellent burying characteristics, and a suitable manufacturing method thereof. SOLUTION: An SiO ₂ film 2 and a wiring pattern 3 made of an Al-based material are formed in this order on a Si substrate 1, and the wiring pattern 3 is covered with an interlayer insulating film 4. The interlayer insulating film 4 is formed by adding fine particles made of a low dielectric constant inorganic material to a resin. As the fine particles, SiO
F, SiOBN, SiBN, and BN are preferable, and the addition of such fine particles can reduce the coefficient of thermal expansion of the resin and increase the glass transition temperature. it can.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a low dielectric constant insulating film, and to a method for manufacturing the semiconductor device.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and high integration of semiconductor devices, wiring patterns have been moving toward miniaturization and multilayering. However, when the step of the interlayer insulating film becomes large and steep due to the miniaturization and high integration of the semiconductor device, the processing accuracy and reliability of the wiring pattern formed thereon decrease, and the reliability of the semiconductor device itself also decreases. It becomes a factor to lower. For this reason, it is difficult to greatly improve the step coverage (coverage) of the wiring layer made of an Al-based material mainly formed by a sputtering method. At present, it is necessary to form a flattened interlayer insulating film. It has been.

In the future, in order to achieve further miniaturization and higher integration of semiconductor devices, it is necessary not only to flatten the interlayer insulating film but also to lower the dielectric constant. This is because, as semiconductor devices are miniaturized and highly integrated, delays in operation speed and increase in power consumption of the semiconductor devices due to parasitic capacitance between wirings become problems.

As a method of forming an interlayer insulating film having a low dielectric constant, a method disclosed in International Conference on Solid State Devices and Materials, 1993, Extended Abstracts of the 1993 I
nternational Conference onSolid State Devices and
Materials, 1993) p161~163 as disclosed, there is a method for forming an SiOF-based insulating film by plasma CVD using a gas obtained by adding C ₂ F ₆ to TEOS and O _2. Proceedings of the 40th Annual Conference of the Japan Society of Applied Physics (Spring Annual Meeting, 1993) 1a-ZV-9 include SiOF-based insulation by plasma CVD using TEOS and a gas obtained by adding NF ₃ to O _2. A method for forming a film is disclosed. In each of the documents, it is shown that the dielectric constant can be reduced by increasing the F concentration in the film.

However, as described above, when an F-based gas is added, the dielectric constant of the insulating film can be reduced, but the film quality deteriorates with an increase in the F concentration, and the hygroscopicity significantly increases. Will occur.

The 40th Japan Society of Applied Physics Related Lectures (1
According to the Proceedings 31a-ZV-9, in order to stabilize the film quality, it is effective to use a SiF ₄ gas containing F together with Si in the same molecule as a source gas. It is shown. However, when an SiOF-based insulating film is formed on a substrate having a step by using this method, the embedding characteristics are locally deteriorated.

Further, the relative dielectric constant of the SiOF-based insulating film as described above is about 3.9 to 3.2, while the relative dielectric constant of the SiO ₂ film is about 3.9. , SiOF
Even if a system-based insulating film is used as an interlayer insulating film, a significant reduction in the dielectric constant cannot be expected.

Therefore, it is expected that a resin film will be used as an interlayer insulating film having a low dielectric constant in the future. For example, a polyimide resin film can realize a low relative dielectric constant of about 3.5 to 3, and a fluorine resin film can realize a low dielectric constant of about 2.5 to 1.9. Specifically, it has a relative dielectric constant such as silylated polymethylsilsesquioxane: 3.0 heat-resistant silicone ladder polymer: 3.1 siloxane-modified polyimide: 3.0 cyclized fluoropolymer: 2.2.

[0009]

However, the resin film as described above has a very large coefficient of thermal expansion as compared with other members constituting the semiconductor device. Thus, for example, as shown in FIG. 4, S the SiO ₂ film 102 is deposited
Wiring pattern 10 made of Al-based material on i-substrate 101
When the interlayer insulating film 104 made of a resin film is formed on the wafer on which the wiring pattern 3 is formed, the interlayer insulating film 104
Gap 105 is likely to be generated.

[0010] Such voids in the interlayer insulating film tend to cause a short circuit between wirings, lowering the yield of the semiconductor device and deteriorating the reliability.

Accordingly, the present invention has been proposed in view of such conventional circumstances, and it is an object of the present invention to provide a semiconductor device having an insulating film which can have a low dielectric constant and has excellent burying characteristics. . It is another object of the present invention to provide a suitable method for manufacturing the semiconductor device.

[0012]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above-mentioned object. In a semiconductor device having at least an insulating film provided on a substrate, the insulating film is formed of a resin. And fine particles made of a low dielectric constant inorganic material (hereinafter referred to as inorganic fine particles).

The insulating film to which fine particles made of an inorganic substance having a low dielectric constant are added (hereinafter referred to as a fine particle-containing resin film) has a lower thermal expansion coefficient and a lower glass than a film made of only a resin. The transition temperature is increased. This is considered to be because the resin is mechanically constrained by the fine particles.

The fine particle-containing resin film having a reduced coefficient of thermal expansion and a raised glass transition temperature is provided on a substrate having a step and subjected to a heat treatment because the shape change due to heat is suppressed. However, it is difficult to form voids.

Here, the inorganic fine particles added to the resin are preferably composed of at least one selected from SiOF, SiOBN, SiBN and BN. The effect of reducing the coefficient of thermal expansion of such inorganic fine particles differs depending on the shape, size, material, etc. of the particles. However, the effect is usually exhibited at an addition amount of 1% by volume or more. The expansion coefficient can be reduced. However, if it exceeds 80% by volume, the dispersibility in the resin is significantly deteriorated. For this reason, the addition amount of the inorganic fine particles is preferably from 1 to 80% by volume, and particularly preferably from 10 to 40% by volume.

It is to be noted that SiOF or the like may have a problem in that it has a high hygroscopic property. However, if heat treatment is performed at a high temperature of 800 ° C. or more when forming the inorganic fine particles, the problem of the hygroscopic property can be solved. It is possible to avoid.

On the surface of the inorganic fine particles, a compound having an affinity for a resin (hereinafter, referred to as a surface treating agent).
Is preferably retained. The surface treatment agent may be appropriately selected depending on the type of the resin used, and examples thereof include those having an amino group or an isocyanate group.

When inorganic fine particles holding such a surface treatment agent are added, the coefficient of thermal expansion can be reduced in accordance with the amount of the added inorganic fine particles, but the effect of reducing the coefficient of thermal expansion is more than additive. This is because the dispersibility of the inorganic fine particles is improved by holding the compound having the affinity for the resin (surface treatment agent), and the inorganic fine particles chemically bind the resin. it is conceivable that.

By the way, in order to manufacture the above-described semiconductor device, an inorganic film made of a resin film containing fine particles is formed by adding and dispersing inorganic fine particles to a resin and then coating the resin on a substrate. I just need.

When the surface treating agent is retained, the surface treating agent may be retained on the surface of the inorganic fine particles before adding the inorganic fine particles to the resin.

As described above, in the semiconductor device according to the present invention, an insulating film having a low dielectric constant and excellent burying characteristics can be obtained. Therefore, if this insulating film is applied as an interlayer insulating film, insulation between wirings can be reliably performed.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment In the present embodiment, the present invention is applied to a semiconductor device as shown in FIG.

In this semiconductor device, an SiO ₂ film 2 and a wiring pattern 3 made of an Al-based material are formed in this order on a Si substrate 1 on which a transistor element is formed, and the wiring pattern 3 is covered with an interlayer insulating film 4. It becomes. The interlayer insulating film 4 is mainly made of siloxane-modified polyimide,
It is obtained by adding 40% by volume of inorganic fine particles made of iOF. As the inorganic fine particles, the particle size is about 0.1 μm,
A material having a substantially spherical shape was used.

In order to manufacture a semiconductor device having such a configuration, first, inorganic fine particles made of SiOF are prepared and heat-treated at 800.degree. Then, 40% by volume of the above-mentioned inorganic fine particles are added to the siloxane-modified polyimide, mixed, and dispersed.

Next, as shown in FIG. 2, an SiO ₂ film 2 and an Al
The siloxane-modified polyimide to which the inorganic fine particles obtained as described above are added is applied by spin coating to the wafer on which the wiring patterns 3 made of the base material are formed in this order. Then, by heating and drying at 200 ° C., a fine particle-containing resin film covering the wiring pattern 3 is formed as the interlayer insulating film 4, and the semiconductor device as shown in FIG. 1 is obtained.

The interlayer insulating film 4 of the semiconductor device having such a structure has a relative dielectric constant of 3.0 and a coefficient of thermal expansion of 5
× 10 ⁻⁵ (/ K), glass transition temperature is 300 ° C.
The relative dielectric constant of the siloxane-modified polyimide single film to which no inorganic fine particles made of SiOF was added was 2.8, the coefficient of thermal expansion was 1 × 10 ⁻¹ (/ K), and the glass transition temperature was 200 ° C.
In comparison with this, it can be seen that the interlayer insulating film 4 in the present embodiment has a low coefficient of thermal expansion and a high glass transition temperature while keeping the dielectric constant low.

Actually, when heat treatment was performed at 400 ° C. for 30 minutes, no gap was generated in the interlayer insulating film 4 between the wiring patterns 3 due to thermal expansion.

From this, it can be seen that in the semiconductor device according to the present embodiment, the interlayer insulating film 4 having a low dielectric constant and excellent burying characteristics is formed.

Second Embodiment In this embodiment, an example in which inorganic fine particles added to the interlayer insulating film 4 are subjected to a surface treatment will be described.

That is, in this semiconductor device, similarly to the first embodiment, an SiO ₂ film 2 and a wiring pattern 3 made of an Al-based material are formed in this order on a Si substrate 1 on which a transistor element is formed. The wiring pattern 3 is an interlayer insulating film 4
Covered.

In this case, the interlayer insulating film 4 is mainly composed of a heat-resistant silicon ladder polymer, and is made by adding 30% by volume of inorganic fine particles made of SiOBN. As the inorganic fine particles, those having a particle diameter of about 0.2 μm and a substantially spherical shape were used. In addition, aminopropyltriethoxysilane, which has an excellent affinity for a heat-resistant silicon ladder polymer, is held as a surface treatment agent on the surface of the inorganic fine particles.

In order to manufacture a semiconductor device having such a configuration, first, pentaeristol monostearate (surfactant) and n-hexane are added to water to form micelles, and then tetraethoxysilane , Triethoxyboron and ammonia were added to perform emulsion polymerization, thereby forming SiOBN particles.
Then, a heat treatment was performed on the obtained SiOBN particles at 600 ° C.

Subsequently, the SiO 2 obtained as described above was obtained.
The BN particles were placed in a reaction vessel containing o-xylene and aminopropyltriethoxysilane at 146 ° C. for 1 hour.
Heated to reflux. As a result, 0.1 g / m ^{2 of} aminopropyltriethoxysilane was held on the surface of the SiOBN particles. Then, into the heat-resistant silicone ladder polymer,
The SiOBN particles were added and mixed so as to be 30% by volume.

Next, as shown in FIG. 2, an SiO ₂ film 2 and an Al
The heat-resistant silicon ladder polymer to which the inorganic fine particles obtained as described above is added is applied by spin coating to the wafer on which the wiring patterns 3 made of the base material are formed in this order. Then, by heating and drying at 200 ° C., a fine particle-containing resin film covering the wiring pattern 3 is formed as the interlayer insulating film 4, and the semiconductor device as shown in FIG. 1 is obtained.

The interlayer insulating film 4 having such a configuration is
The relative dielectric constant is 3.0, and the coefficient of thermal expansion is 6 × 10 ⁻⁵ (/
K), the glass transition temperature becomes 250 ° C. The heat-resistant silicon ladder polymer alone film to which no SiOBN particles are added has a relative dielectric constant of 2.8 and a thermal expansion coefficient of 1 × 10 ⁻¹ (/
K) Compared with the fact that the glass transition temperature is 150 ° C., the interlayer insulating film 4 according to the present embodiment has a reduced coefficient of thermal expansion and a high glass transition temperature while keeping the dielectric constant low. I understand.

Actually, when heat treatment was performed at 400 ° C. for 30 minutes, no void was generated between the wiring patterns 3 due to thermal expansion.

From this, it can be seen that in the semiconductor device according to the present embodiment, an interlayer insulating film 4 having a low dielectric constant and excellent burying characteristics was formed. Further, in the present embodiment, since aminopropyltriethoxysilane having excellent affinity with the heat-resistant silicon ladder polymer is held on the surface of the inorganic fine particles made of SiOBN, the structure is smaller than that of the first embodiment. Even so, the effect of reducing the coefficient of thermal expansion is large.

Although the embodiments of the semiconductor device according to the present invention have been described above, it is needless to say that the present invention is not limited to the above embodiments. For example,
As the resin, instead of siloxane-modified polyimide or heat-resistant silicone ladder polymer, silylated polymethylsilsesquioxane, cyclopolymerized fluororesin, polysulfone (PSF), polyethersulfone (PES), polyetheretherketone (PEEK) , BCB resin, cyclo-α, α, α ′, α ′ etrafluoroρ-xylene and the like may be used. Also, as inorganic fine particles, SiOF,
Instead of SiOBN, a low dielectric substance such as SiBN or BN may be used.

Further, as a surface treating agent to be held on the surface of the inorganic fine particles, aminopropyltriethoxy can be used as long as it is a compound which can be held well on the surface of the inorganic fine particles and has excellent affinity with the resin. Not limited to silane. For example, as a compound having an amino group, aminoethylaminopropyltriethoxysilane and the like can be used,
As the compound having an isocyanate group, isocyanate propyl triethoxy silane, isocyanate ethyl isocyanate propyl triethoxy silane, or the like can be used.

Further, the amount of the inorganic fine particles to be added and the amount of the surface treating agent retained on the inorganic fine particles for the purpose of improving the affinity with the resin can be appropriately changed.

In addition, the configuration of a wafer on which a film is formed by applying the present invention, various manufacturing conditions, and the like can be appropriately changed.

[0043]

EXAMPLES Here, the following experiments were conducted in order to show the effects of the present invention.

That is, with respect to the polyimide resin, the particle size is 0.1 mm.
After adding 1 μm substantially spherical SiOF particles in the range of 0 to 60% by volume and mixing them, the thermal expansion coefficient was measured.
Further, the thermal expansion coefficient was measured in the same manner except that aminopropyltriethoxysilane was held at 0.1 g / m ² in the above-mentioned SiOF particles. The result is shown in FIG.

FIG. 3 shows that the thermal expansion coefficient is reduced by adding SiOF particles to the resin. In addition, it can be seen that the effect of reducing the coefficient of thermal expansion is further improved by coating the surface of the SiOF particles with aminopropyltriethoxysilane.

Further, those having various added amounts of SiOF particles were actually applied onto a wafer having a step as shown in FIG. As a result, the amount of SiOF particles added was 8
When the content exceeds 0% by volume, it has been found that the dispersibility of the SiOF particles is remarkably deteriorated and good coating cannot be performed. When the range in which the thermal expansion coefficient was suppressed and a coating film having good film quality was formed was examined, it was found that SiOF
It was found that the amount of added particles was in the range of 10 to 40% by volume.

[0047]

As is apparent from the above description, when the present invention is applied, an insulating film having a low dielectric constant and excellent burying characteristics can be formed.

Therefore, in a semiconductor device in which this insulating film is used as an interlayer insulating film, the parasitic capacitance between the miniaturized and multi-layered wiring patterns is reduced, and the insulation between the wirings can be reliably performed.

Therefore, by applying the present invention, the operation speed can be improved and the power consumption can be reduced.
A highly reliable semiconductor device can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing one configuration example of a semiconductor device of the present invention.

FIG. 2 is a schematic cross-sectional view showing a step of manufacturing the semiconductor device of the present invention and showing a wafer on which a wiring pattern is formed.

FIG. 3 is a characteristic diagram showing a relationship between an added amount of inorganic fine particles and a coefficient of thermal expansion.

FIG. 4 is a schematic cross-sectional view illustrating a configuration example of a conventional semiconductor device and showing a state in which a gap is generated by heat treatment in an interlayer insulating film made of a resin.

[Explanation of symbols]

1 Si substrate, 2 SiO ₂ film, 3 wiring pattern, 4 interlayer insulating film

[Procedure amendment]

[Submission date] August 26, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0027

[Correction method] Change

[Correction contents]

The interlayer insulating film 4 of the semiconductor device having such a structure has a relative dielectric constant of 3.0 and a coefficient of thermal expansion of 5
× 10 ⁻⁵ (/ K), glass transition temperature is 300 ° C.
The relative dielectric constant of the siloxane-modified polyimide single film to which no inorganic fine particles made of SiOF was added was 2.8, the coefficient of thermal expansion was 1 × 10 ⁻⁴ (/ K) , and the glass transition temperature was 200 ° C.
In comparison with the above, it can be seen that the interlayer insulating film 4 in the present embodiment has a low coefficient of thermal expansion and a high glass transition temperature while keeping the dielectric constant low.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction contents]

The interlayer insulating film 4 having such a configuration is
The relative dielectric constant is 3.0, and the coefficient of thermal expansion is 6 × 10 ⁻⁵ (/
K), the glass transition temperature becomes 250 ° C. The heat-resistant silicon ladder polymer alone film to which no SiOBN particles are added has a relative dielectric constant of 2.8 and a thermal expansion coefficient of 1 × 10 ⁻⁴ (/
K) Compared with the fact that the glass transition temperature is 150 ° C., the interlayer insulating film 4 in the present embodiment has a lower coefficient of thermal expansion and a higher glass transition temperature while keeping the dielectric constant low. I understand.

Claims (8)

[Claims] 1. A semiconductor device in which at least an insulating film is provided on a substrate, wherein the insulating film is obtained by adding fine particles made of a low dielectric constant inorganic material to a resin. Semiconductor device. 2. The method according to claim 1, wherein the fine particles are SiOF, SiOBN,
2. The semiconductor device according to claim 1, wherein the semiconductor device comprises at least one selected from SiBN and BN. 3. The semiconductor device according to claim 1, wherein a compound having an affinity for a resin is held on the surface of the fine particles. 4. The semiconductor device according to claim 3, wherein said compound has an amino group or an isocyanate group. 5. A method for manufacturing a semiconductor device, comprising adding fine particles of a low dielectric constant inorganic material to a resin, dispersing the fine particles, and applying the fine particles on a substrate to form an insulating film. 6. The fine particles of SiOF, SiOB
6. The method for manufacturing a semiconductor device according to claim 5, wherein the device comprises at least one selected from N, SiBN, and BN. 7. The semiconductor device according to claim 5, wherein a compound having an affinity for the resin is held on the surface of the fine particles before adding the fine particles to the resin. Production method. 8. The method according to claim 7, wherein the compound having an amino group or an isocyanate group is used.