JPH11209624A - Composite of fluororesin with inorganic/organic hybrid and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-hardness low-permittivity material as an insulation material used in electronic devices by uniformly compositing a fluororesin with an inorganic/organic hybrid. SOLUTION: There is provided a composite material prepared by compositing a fluororesin with an inorganic/organic hybrid formed by replacing 50-95 mol.% of Ms in an inorganic polymer skeleton having M-O-M bonds (wherein M is a metal or a semi-metal atom) by Si(R)n (O-)4-n groups (wherein R is an organic group; and n is an integer of 1, 2 or 3, provided that the hydrogen atoms of the organic group have been replaced by fluorine atoms and/or chlorine atoms). In the inorganic/organic hybrid, the organic group has an atomic ratio X/(X+H) of 0.01-1 (wherein X=F+Cl). The volume ratio of the inorganic/organic hybrid to the fluoro resin is in the range of 10:90 to 80:20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite of a fluorine resin and an inorganic / organic hybrid suitable for an insulating material used in electronic devices such as LSI elements, electronic circuits, and semiconductor circuits, and to a method for producing the same.

[0002]

2. Description of the Related Art As the speed of LSI elements becomes higher, the degree of integration becomes higher, and the frequency of electric circuits becomes higher in mobile communications, the problem of signal delay due to the dielectric constant of insulating materials used therein and the electric resistance of wiring conductors arises. It is getting serious. The signal delay is represented by the product of the resistance R of the wiring and the capacitance C between the wirings. In order to minimize the delay, it is effective to reduce the dielectric constant of the insulating material, in addition to reducing the wiring resistance.

For example, in an insulating film of an LSI element,
A silica material obtained by forming a sol formed by hydrolyzing tetraalkoxysilane by a spin-on-glass (SOG) method is used. However, the molecular structure of the material thus manufactured is a dense three-dimensional network structure of {Si-O-Si}, and the relative dielectric constant is as high as 4.0. As a method for lowering the relative dielectric constant, a film formation of SiOF by CVD or the like, a film formation of an organic material, a porous film, and the like have been proposed. SiOF has a dielectric constant of 3. with increasing F content.
Although it is reduced to about 3, there is a problem that the hygroscopicity increases with the amount of F. As the organic material such as a fluororesin, a low dielectric constant material having a dielectric constant of up to about 2.2 has been obtained, but has problems of heat resistance and adhesion to a substrate. The dielectric constant of porous materials can be reduced from 4.7 to 2.3 depending on the amount of pores [Aoi, Proceedings of the 43rd JSAP, 26
pN-5 (1996)]. However, it is difficult to use it for ordinary semiconductor devices and electric circuit components because of its problem of hygroscopicity.

[0004] On the other hand, in the case of SOG, it has hitherto been the biggest problem to apply a thick film without cracks. If the silica glass film is made thick, cracks are likely to be formed during evaporation or thermal shrinkage of the solvent. Therefore, a film into which H is introduced and a film into which an organic component is introduced (organic SOG film) have been developed. 2. Since the organic SOG film has a relatively small polarization and contains a bulky organic group, the organic SOG film has a lower dielectric constant than SOG containing only an inorganic component.
About four are commercially available. However, it is considered that an insulating film having a relative dielectric constant of 3 or less is required from the demand for higher speed and a higher frequency ratio.

Further, ceramic substrates such as alumina have been used as IC insulating substrates. In high-frequency circuits where signal delay due to the dielectric constant of the insulator is a problem,
There is a limit in reducing the dielectric constant of ceramics, and an organic material having a low dielectric constant such as a fluororesin is used. Fluororesin is the material with the lowest dielectric constant, but has low hardness and is easily scratched.

In recent material research, attention has been focused on an inorganic / organic hybrid in which an inorganic substance and an organic substance are combined at a molecular level. Examples include organically modified silicates (A.
Kaiser et al., J. Membrance Soc. 22 , 257-268 (198
5)) and ceramers (GL Wilkes et al., Polym. Prep.
26 , 300-302 (1985), H.-H. Huang et al., Polymer.Bu
ll. 14 , 557-564 (1985)). These have a structure in which an organic group is introduced into a Si—O glass network, and are synthesized by a hydrolysis / polycondensation reaction of an alkylalkoxysilane or the like. These inorganic / organic hybrids are homogeneous, but by forming a composite structure in which various inorganic particles of the inorganic / organic hybrid are dispersed, the characteristics can be improved or a new function can be imparted. For example, compatibility between hardness and flexibility (JP-A-7-278)
No. 311), imparting lubricity (JP-A-8-13448)
No. 5 gazette).

[0007]

As a material having a low dielectric constant having a high hardness, a composite of a fluororesin having a low dielectric constant and an inorganic material such as silica may be considered. In some cases, such dispersion is difficult, or the interface is weak and the strength of the composite is insufficient. Further, a method of adding a fluororesin powder in the process of producing silica or an inorganic / organic hybrid by a sol-gel method is also conceivable, but it is difficult to uniformly disperse the fluororesin powder.

The present invention has been made in view of these points, and has as its object to provide a material having a low dielectric constant and a high hardness by uniformly compounding a fluorine resin and an inorganic / organic hybrid.

[0009]

In order to achieve the above-mentioned object, the present invention provides (1) a method in which M in an inorganic polymer skeleton having an MOM bond (M is a metal or metalloid atom) is 50 or more. Is substituted with a Si (R) _n (O—) _4-n group (where R is an organic group and n is an integer of 1, 2 or 3) at a ratio of up to 95 mol%, and A composite in which an inorganic / organic hybrid partially or entirely substituted with a fluorine atom and / or a chlorine atom is combined with a fluororesin. (2) The composite according to (1), wherein the organic group of the inorganic / organic hybrid has an atomic ratio X / (X + H) (where X = F + Cl) of 0.01 to 1. (3) The composite according to the above (1) or (2), wherein the volume ratio between the inorganic / organic hybrid and the fluororesin is in the range of 10:90 to 80:20. (4) the fluororesin is polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluorovinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene (1) which is one or more of copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), and polyvinylidene fluoride (PVDF) A composite according to 2) or 3).

The above (1), (2), (3) or (4)
The described conjugate is prepared as follows. Dissolve one or two of metal alkoxide and organoalkoxysilane and polydimethylsiloxane in an organic solvent, further dissolve one or two of fluoroalkylalkoxysilane and chloroalkylalkoxysilane, and then dissolve in water. Is added and mixed with the hydrolyzed solution, followed by aging and gelling to produce a solution.
Alternatively, one or two of metal alkoxide and organoalkoxysilane and polydimethylsiloxane are dissolved in an organic solvent, and one or two of fluoroalkylalkoxysilane and chloroalkylalkoxysilane are dissolved. After adding and mixing a fluororesin powder, water is added to hydrolyze, aged and gelled to produce. Alternatively, one or two of metal alkoxide and organoalkoxysilane and polydiorganosiloxane are dissolved in an organic solvent, and one or two of fluoroalkylalkoxysilane and chloroalkylalkoxysilane are dissolved. A solution obtained by adding a fluororesin powder to a solution hydrolyzed by adding water is coated on a substrate, and then dried and heat-treated to manufacture. Alternatively, one or two of metal alkoxide and organoalkoxysilane and polydiorganosiloxane are dissolved in an organic solvent, and one or two of fluoroalkylalkoxysilane and chloroalkylalkoxysilane are dissolved. After adding and mixing a fluororesin powder, a solution hydrolyzed by adding water is coated on a substrate, and then dried and heat-treated.

Further, the present invention uses the composite described in (1), (2), (3) or (4) as an interlayer insulating film for a semiconductor device, an electric circuit board, or an IC sealing material. The main purpose is to do.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In an inorganic / organic hybrid, a metal alkoxide reacts with polydimethylsiloxane or a silanol group of a hydrolyzed organoalkoxysilane to form an MOM bond (where M is a metal or semimetal). Atom) as the skeleton of the inorganic polymer composed of Si (R) _m (O
−) It is manufactured by forming a structure substituted with a _{(4-m) / 2} group or a —O-[— Si (R) ₂ —O—] _n group (where R is an organic group). In such a structure, a metal or metalloid is chemically bonded to an organic substance composed of carbon, hydrogen, oxygen, nitrogen, or the like and polymerized, thereby being fused at an atomic / molecular level.

In the present invention, since the inorganic / organic hybrid contains a fluorine group or a chlorine group at the molecular level, it has a good affinity with the fluororesin, and becomes a uniformly dispersed complex. A wide range of complexes can be obtained.

In the present invention, the fluororesin includes polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluorovinyl ether copolymer (PFA),
Tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polyfluorinated Vinylidene (PVDF). More preferred is PTFE, P
FA, ETFE, and PCTFE.

The inorganic polymer is a macromolecule polymerized in a chain, planar or three-dimensional form with an MOM bond as a skeleton. The MOM bond represents an inorganic component.
Here, M is limited to those capable of forming a metal alkoxide. The metal alkoxide of the present invention is represented by the chemical formula M (OR) _n . Here, M is a metal or metalloid, for example, B, Si, Al, T
i, Zr, Ta, Nb, Y, Co, etc. R is an organic group, and n is a valence of a metal or metalloid M. One or more of these metal alkoxides can be used.

Si (R) _m (O-) _{(4-m) / 2} group and-
The organic group R in the O-[-Si (R) ₂ -O-] _n group includes, for example, -CH ₃ , -C ₂ H ₅ , -C ₃ H ₇ , -C
_{4 H 9, -CH = CH 2} , -C 6 H 5, -CF 3, -C
_{2 F 5, -C 3 F 7} , -C 4 F 9, -CH 2 CH 2 CF
_{3, -CH 2 CH 2 C 6} F 13, -CH 2 CH 2 C 8 F 17
Etc., which represents an organic component.

In the inorganic / organic hybrid, M in the inorganic polymer skeleton having an MOM bond is 50 to 95 mol%.
Is preferably substituted with Si (R) _n (O—) _4-n group. When the content of the Si (R) _n (O—) _4-n group is less than 50 mol%, the amount of the organic component is reduced, and the affinity with the fluororesin is reduced. The rate is undesirably high. On the other hand, when the content of the Si (R) _n (O—) _4-n group exceeds 95% by mole, the organic component is increased and the flexibility becomes too high, so that the hardness becomes low. More preferably, it is in the range of 70 to 90 mol%.

In the organic group of the inorganic / organic hybrid, the atomic ratio X / (X + H) (where X = F + Cl) is preferably in the range of 0.01 to 1. Atomic ratio X / (X + H)
Is less than 0.01, the content of a fluorine group or a chlorine group decreases, the affinity with the fluororesin decreases, and a uniform composite cannot be obtained. More preferably, it is in the range of 0.1 to 1.

The volume ratio between the inorganic / organic hybrid and the fluororesin is preferably in the range of 10:90 to 80:20. If the ratio of the fluororesin is small and less than the ratio of 80:20,
The decrease in the dielectric constant is small and not practical. If the ratio of the fluororesin is large and exceeds the ratio of 10:90, the hardness becomes low, which is not practical. More preferably, from 40:60 to 6
The range is 0:40.

The composite of the present invention is prepared by dissolving a metal alkoxide and an organoalkoxysilane in an organic solvent, further dissolving one or two of fluoroalkylalkoxysilane and chloroalkylalkoxysilane, and then adding water. Fluororesin powder is added to the hydrolyzed solution, mixed, and then aged and gelled to produce. Alternatively, a metal alkoxide and an organoalkoxysilane are dissolved in an organic solvent, one or two of a fluoroalkylalkoxysilane and a chloroalkylalkoxysilane are further dissolved, and then a fluororesin powder is added and mixed. In addition, it is hydrolyzed, aged and gelled to produce.

The composite thin film of the present invention is obtained by dissolving a metal alkoxide and an organoalkoxysilane in an organic solvent,
Further, one or two of fluoroalkylalkoxysilane and chloroalkylalkoxysilane are dissolved, and then a solution obtained by adding water and then hydrolyzing the solution and adding a fluororesin powder to the mixture is coated on a substrate.
It is manufactured by drying and heat treatment. Alternatively, a metal alkoxide and an organoalkoxysilane are dissolved in an organic solvent, one or two of a fluoroalkylalkoxysilane and a chloroalkylalkoxysilane are further dissolved, and then a fluororesin powder is added and mixed. After coating the substrate with the hydrolyzed solution,
It is manufactured by drying and heat treatment.

The metal alkoxide used in the present invention is not particularly restricted but includes, for example, methoxide, ethoxide, propoxide, butoxide and the like. The metal alkoxide has a part of the alkoxy group, β-diketone,
It may be used after substituting with β-ketoester, alkanolamine, alkylalkanolamine, organic acid and the like.

The organoalkoxysilane used in the present invention is represented by the chemical formula Si (R) _m (OR ″) _{(4-m) / 2} , and the organic group R is represented by —CH ₃ , —C ₂ H ₅ , C ₃ H _7, -
_{C 4 H 9, -CH = CH} 2, -C 6 H 5, -CF 3, -
_{C 2 F 5, -C 3 F} 7, -C 4 F 9, -CH 2 CH 2 C
_{F 3, -CH 2 CH 2 C} 6 F 13, -CH 2 CH 2 C 8 F
_17, etc., in which the alkoxy group —OR ″ is composed of a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc. The organoalkoxysilane is hydrolyzed in advance with an equimolar amount or less of water relative to the alkoxy group ( (Partial hydrolysis).

The polydiorganosiloxane used in the present invention has the chemical formula HO — [— Si (R) ₂ —O—] _n —H
In a linear polymer represented, the organic group R is -CH _{3,
-C 2 H 5, -C 3 H} 7, -C 4 H 9, -CH = C
H _2, are those composed of -C ₆ H ₅ and the like. For example,
Polydimethylsiloxane, polydiethylsiloxane, polydipropylsiloxane, polydiphenylsiloxane,
And polymethylphenylsiloxane. However, when n exceeds 500, it does not dissolve in the solvent, or the proportion of the hydroxyl group, which is a reaction point, occupies a small amount, so that an inorganic / organic hybrid cannot be synthesized.

In the hydrolysis of the present invention, water is added in an amount of 0.5 to 10 times the mole of the alkoxy group. At this time, an inorganic acid, an organic acid or both of them are used as a catalyst.
The water to be added may be diluted with an organic solvent such as alcohol.

The composite according to the present invention can be applied to various electronic parts as an insulating material such as an interlayer insulating film for a semiconductor device, an electric circuit board, and an IC sealing material.

[0027]

Hereinafter, specific examples of the present invention will be described.
The present invention is not limited to only these examples. The raw materials shown in Table 1 were mixed with an ethanol solvent, and hydrolyzed by adding water under a hydrochloric acid catalyst. Fluororesin particles were added to the hydrolysis solution to prepare a dispersion solution. The dispersion solution was gelled at 70 ° C. and then heat-treated at 300 ° C. to produce a composite of inorganic / organic hybrid and PTFE.
The hardness was measured by Rockwell hardness according to JIS K7202. The relative permittivity was measured with an impedance analyzer by attaching Al electrodes to both surfaces of the plate-like sample. Example 1
In Nos. 6 to 6, a fluoro group and a chlorine group were introduced into an inorganic / organic hybrid structure using fluoroalkylalkoxysilane and chloroalkylalkoxysilane to be combined with fluororesin particles. In all cases, a uniform composite was obtained, and the added fluororesin (PCTFE: R110, P110
Hardness is higher than TFE: D65 (Shore hardness; cannot be measured by Rockwell hardness because of softness) and the relative dielectric constant is as low as 2.2 to 2.5. As shown in Comparative Example 9, the values of these relative dielectric constants are the values of inorganic-organic hybrids not combined with a fluororesin (3.
This is significantly lower than the value (3.0) when the composite ratio of the fluororesin is too small as shown in 2) and Comparative Example 8. Further, as shown in Comparative Example 7, when no fluorine group was introduced into the inorganic / organic hybrid structure,
It was difficult to uniformly disperse the fluororesin particles, and a composite was not obtained.

Using the dispersions of Examples 1 to 6, a platinum film having a thickness of 1000 ° was applied to a sputtered Si substrate by a spin coater, and then heated on a hot plate at 150 ° C. for 5 minutes for 300 minutes.
Heat treatment was performed on a hot plate at 30 ° C. for 30 minutes to produce a composite thin film. 1000mm thick Al on the thin film 1mm in diameter
When the dielectric constant was measured using an impedance analyzer, the relative dielectric constants of these thin films were the same as those shown in Table 1.

[0029]

[Table 1]

[0030]

Since the present invention is configured as described above, it has the following effects. Since a fluorine group is introduced from the manufacturing process into the structure of the inorganic / organic hybrid, it can be uniformly compounded with the fluororesin. As a result, a material having a low dielectric constant and a high hardness can be provided, which is useful as an insulating material in electronic devices such as LSI elements, electronic circuits, and semiconductor circuits.

Claims (11)

[Claims] 1. The method according to claim 1, wherein M in the inorganic polymer skeleton having an MOM bond (where M is a metal or metalloid atom) is from 50 to 50.
95% by mole of Si (R) _n (O-) _4-n group (where R is an organic group, n is an integer of 1, 2 or 3), and a hydrogen atom of the organic group A composite comprising an inorganic / organic hybrid partially or entirely substituted with a fluorine atom and / or a chlorine atom and a fluororesin. 2. The composite according to claim 1, wherein an atomic ratio X / (X + H) (where X = F + Cl) in the organic group of the inorganic / organic hybrid is 0.01 to 1. 3. The composite according to claim 1, wherein the volume ratio between the inorganic / organic hybrid and the fluororesin is in the range of 10:90 to 80:20. 4. The fluororesin is polytetrafluoroethylene, tetrafluoroethylene-perfluorovinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, polychlorotrifluoroethylene. 4. The composite according to claim 1, wherein the composite is one or more of ethylene, chlorotrifluoroethylene copolymer, and polyvinylidene fluoride. 5. A metal alkoxide, an organoalkoxysilane and one or two of polydimethylsiloxane are dissolved in an organic solvent, and one or two of fluoroalkylalkoxysilane and chloroalkylalkoxysilane are dissolved. The method for producing a composite according to any one of claims 1, 2, 3 and 4, wherein the fluororesin powder is added to a solution obtained by dissolving and then hydrolyzing by adding water, followed by mixing and then aging and gelling. 6. A metal alkoxide, an organoalkoxysilane and one or two of polydimethylsiloxane are dissolved in an organic solvent, and a fluoroalkylalkoxysilane and a chloroalkylalkoxysilane are dissolved one or two of them. 5. The method for producing a composite according to claim 1, wherein the fluororesin powder is added and mixed, and then the mixture is hydrolyzed by adding water to ripen and gel. 7. One or two kinds of metal alkoxide, organoalkoxysilane and polydiorganosiloxane are dissolved in an organic solvent, and one or two kinds of fluoroalkylalkoxysilane and chloroalkylalkoxysilane are dissolved. The composite according to any one of claims 1, 2, 3 and 4, wherein the substrate is coated with a solution obtained by adding a fluororesin powder to a solution hydrolyzed by adding water and then mixed, followed by drying and heat treatment. Manufacturing method. 8. Dissolving one or two of metal alkoxide, organoalkoxysilane and polydiorganosiloxane in an organic solvent, and further dissolving one or two of fluoroalkylalkoxysilane and chloroalkylalkoxysilane The composite according to any one of claims 1, 2, 3, and 4, further comprising: adding and mixing a fluororesin powder; coating the substrate with a solution hydrolyzed by adding water; and drying and heat-treating the substrate. Manufacturing method. 9. An interlayer insulating film for a semiconductor device, comprising the composite according to claim 1. Description: 10. An electric circuit board comprising the composite according to claim 1, 2, 3, or 4. 11. An IC encapsulant comprising the composite according to claim 1, 2, 3, or 4.