JP2005268532A - Porous resin film, its manufacturing method and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the manufacturing method of a porous resin film capable of efficiently producing the porous resin film having a low dielectric constant and excellent in resistance to heat, the porous resin film excellent in characteristics when the same is employed as an interlayer insulating film or a semiconductor protective film, and a semiconductor device excellent in characteristics. <P>SOLUTION: The manufacturing method of porous resin film comprises a process wherein activating energy is irradiated against a resin film constituted of a thermosetting resin comprising a resolvable constituent and, in this case, the decomposition of the resolvable constituent and the curing of the thermosetting resin are effected in the activating energy irradiating process. Further, the porous resin film is employed as the interlayer insulating film or the semiconductor protective film. The semiconductor device is provided with the porous resin film obtained by the manufacturing method of porous resin film which is described in either one of the aforementioned methods. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a porous resin film, a method for manufacturing a porous resin film, and a semiconductor device.

  Currently, an oxide film (SiOx film) produced by a CVD method (chemical vapor deposition method) or the like is mainly used as an interlayer insulating film for a semiconductor. However, since an inorganic insulating film such as an oxide film has a high dielectric constant, it is difficult to cope with higher speed and higher performance of a semiconductor. Therefore, application of an organic insulating film as an interlayer insulating film having a low dielectric constant has been studied. An organic material used for the interlayer insulating film is required to have excellent heat resistance and a low dielectric constant.

Conventionally, as an organic insulating film, a polyimide resin excellent in heat resistance, electrical characteristics, mechanical characteristics, and the like has been used for solder resists, coverlays, liquid crystal alignment films, and the like.
However, it has been pointed out that an organic insulating film made of polyimide resin is inferior in adhesion because varnish is applied to a wafer to form a film. Therefore, in order to improve the adhesion, various primer treatment methods have been studied, but problems such as an increase in dielectric constant have occurred.

As a technique for reducing the dielectric constant, a method of reducing the dielectric constant by forming micropores in the film by utilizing the relative dielectric constant of air being 1 has been studied. Specifically, as a technique for obtaining micropores on the order of submicrometers, a method is disclosed in which a block copolymer is heat-treated to produce a resin having micropores on the order of submicrometers (for example, Patent Document 1). reference).
However, such a method has a problem in productivity because the heating time for forming micropores in the film is long.

US Pat. No. 5,776,990

An object of the present invention is to provide a method for producing a porous resin film that can efficiently produce a porous resin film having a low dielectric constant and excellent heat resistance.
Another object of the present invention is to provide a porous resin film having excellent characteristics when used as an interlayer insulating film or a semiconductor protective film.
Another object of the present invention is to provide a semiconductor device having excellent characteristics.

Such an object is achieved by the present invention described in the following (1) to (19).
(1) A method for producing a porous resin film comprising a step of irradiating a resin film composed of a thermosetting resin containing a decomposable component with activation energy,
In the step of irradiating the activation energy, the decomposable component is decomposed and the thermosetting resin is cured.
(2) The method for producing a porous resin film according to the above (1), comprising a step of washing the resin film after the step of irradiating the activation energy.
(3) The method for producing a porous resin film according to (2) or (3), wherein the activation energy irradiation is electron beam irradiation or ultraviolet irradiation.
(4) The method for producing a porous resin film according to any one of (1) to (3), further including a step of heat-treating the resin film after the step of irradiating the activation energy.
(5) The method for producing a porous resin film according to (4), wherein the cleaning step is performed before the heat treatment step or after the heat treatment step.
(6) The method for producing a porous resin film according to any one of the above (2) to (5), wherein the washing step removes the residue of the decomposable component with a washing solution.
(7) The method for producing a porous resin film according to any one of (1) to (6), wherein the decomposable component is a degradable oligomer.
(8) The method for producing a porous resin film according to (7), wherein the decomposable oligomer is a thermally decomposable oligomer.
(9) The method for producing a porous resin film according to (8), wherein the thermally decomposable oligomer is polyoxyalkylene.
(10) The method for producing a porous resin film according to any one of (1) to (9), wherein the resin film is a copolymer of the decomposable component and a thermosetting resin.
(11) The method for producing a porous resin film according to (10), wherein the thermosetting resin includes a benzoxazole resin and / or a benzoxazole resin precursor.
(12) The method for producing a porous resin film according to any one of (1) to (11), wherein the step of irradiating the activation energy is performed in an inert gas atmosphere.
(13) The method for producing a porous resin film according to (12), wherein the oxygen concentration in the inert gas atmosphere is 300 ppm or less.
(14) The method for producing a porous resin film according to any one of (1) to (13), wherein the step of irradiating the activation energy decomposes the decomposable component by 20% or more.
(15) The step of irradiating the activation energy is to produce the porous resin film according to any one of (1) to (14), wherein the degree of cure of the thermosetting resin is 30% or more. Method.
(16) The method for producing a porous resin film according to any one of (1) to (15), wherein the porosity of the porous resin film is 10% or more.
(17) The method for producing a porous resin film according to any one of (1) to (16), wherein an average pore diameter of the porous resin film is 20 nm or less.
(18) The porous resin film obtained by the method for producing a porous resin film according to any one of (1) to (17) is used as an interlayer insulating film or a semiconductor protective film. Porous resin film.
(19) A semiconductor device comprising a porous resin film obtained by the method for producing a porous resin film according to any one of (1) to (18).

According to the present invention, it is possible to efficiently produce a porous resin film having a low dielectric constant and excellent heat resistance.
Moreover, when it has the process of heat-processing, decomposition | disassembly of a decomposable component can be performed especially reliably.
Moreover, when it has the process to wash | clean further, the heat processing time of the process to heat-process can be shortened. Furthermore, the temperature of the heat treatment step can be lowered.
In addition, according to the present invention, a porous resin film having excellent characteristics when used as an interlayer insulating film or a semiconductor protective film can be obtained.
Further, if necessary, it is optionally possible to accelerate the decomposition of the decomposable component and the curing of the thermosetting resin by using rapid heating in combination with a hot plate or the like.
In addition, according to the present invention, a semiconductor device having the excellent porous resin film as described above can be obtained.
Further, according to the present invention, a semiconductor device with a small wiring delay can be obtained.

Hereinafter, a method for producing a porous resin film, a porous resin film, and a semiconductor device of the present invention will be described.
The method for producing a porous resin film of the present invention is a method for producing a porous resin film comprising a step of irradiating activation energy to a resin film composed of a thermosetting resin containing a decomposable component, In the step of irradiating the forming energy, the decomposable component is decomposed and the thermosetting resin is cured.
The porous resin film of the present invention is used as an interlayer insulating film or a semiconductor protective film.
The semiconductor device of the present invention is characterized by having a porous resin film obtained by any one of the above-described methods for producing a porous resin film.

Hereinafter, the manufacturing method of a porous resin film and a porous resin film will be described.
FIG. 1 is a process diagram showing an example of a method for producing a porous resin film of the present invention. FIG. 2 is a process diagram showing another example of the method for producing a porous resin film of the present invention.
First, A step (FIG. 1) which is a preferred embodiment of the method for producing a porous resin film of the present invention will be described.
1. Step A In step A, the step (1A) of irradiating the resin film composed of a thermosetting resin containing a decomposable component with activation energy, the step (2A) for cleaning the resin film, and the resin film And a heat treatment step (3A). Thereby, a resin film having uniform holes can be obtained.

Preprocess (Manufacture of resin film)
The resin film used in the present invention is composed of a thermosetting resin containing a decomposable component.
Examples of the decomposable component include a component that decomposes by heat, a component that decomposes by ultraviolet rays, and a component that decomposes by electron beams. Specifically, cyclodextrins, organic compounds with high melting points, surfactants, azobis compounds, organic oxides, dendrimers, hyperbranched polymers and other foaming agents, polyoxyalkylenes, polyalkylamides, polyacetals, celluloses, polyesters, Examples include polycarbonate.
Among these, the component decomposed by heat represented by the thermally decomposable oligomer is preferable. Thereby, the process to the heat processing after the process of rapid heating can be simplified, and workability can be improved.

The thermally decomposable oligomer has a unit that decomposes a decomposition product. The degradable oligomer is not particularly limited, but is preferably one that is easily decomposed at a temperature lower than the decomposition temperature of the thermosetting resin.
Examples of the thermally decomposable oligomer include polyoxymethylene, polyoxyethylene, polyoxymethylene-oxyethylene copolymer, polyoxymethylene-oxypropylene copolymer, polyoxyethylene-oxypropylene copolymer, polytetrahydrofuran and the like. Preferred examples include polyoxyalkylenes such as polymethyl methacrylate, polyurethane, poly α-methyl styrene, polystyrene, polyester, polyether ester, polycarbonate, and polycaprolactone. Among these, polyoxyalkylene is preferable. Is more preferable. These may be used alone or in combination of two or more.

When the matrix polymer is a benzoxazole resin precursor as described later, the thermally decomposable oligomer is preferably a thermally decomposable oligomer having a functional group capable of reacting with a diaminodihydroxy compound or a dicarboxylic acid compound.
The thermally decomposable oligomer having the functional group may be used simply by mixing with the benzoxazole resin precursor, but the thermally decomposable oligomer having the functional group is previously used as the diaminodihydroxy compound or the dicarboxylic acid compound. It is more preferable to introduce it by reacting with a benzoxazole resin precursor obtained from the diaminodihydroxy compound or the dicarboxylic acid compound. Thereby, the dispersibility of the thermally decomposable oligomer can be improved, and the fineness and uniformity of the pore structure can be improved.

Examples of the thermally decomposable oligomer having a functional group include those having a functional group such as a carboxyl group, an isocyanate group, an amino group, and a hydroxyl group.
The functional group can be introduced by reacting with a carboxyl group, amino group, or hydroxyl group of the diaminodihydroxy compound or the dicarboxylic acid compound, and the functional group is a side chain or main chain of the thermally decomposable oligomer. Those introduced at one end or both ends of can be used.
Industrially available are thermally decomposable oligomers having modified main chain ends, such as 4-aminobenzoate ester-terminated styrene oligomers and 4-aminobenzoate ester-terminated poly (propylene glycol) oligomers. And both hydroxy-terminated poly (ethylene glycol) -block-poly (propylene glycol) -block-poly (ethylene glycol), poly (propylene glycol) bis (2-aminopropyl ether) and the like.

  The number average molecular weight of the decomposable oligomer (particularly the thermally decomposable oligomer) is not particularly limited, but is preferably 100 to 40,000, particularly preferably 500 to 20,000, and most preferably 1,000 to 10,000. If the number average molecular weight is less than the lower limit, the void after decomposition and vaporization is too small and easily crushed, so the effect of reducing the relative permittivity may be reduced, and if the upper limit is exceeded, the void becomes larger. In some cases, the mechanical properties of the resin film may deteriorate.

  The content of the decomposable component is preferably 5 to 70% by weight of the entire resin film, particularly preferably 8 to 50% by weight, and most preferably 10 to 40% by weight. If the content is less than the lower limit, the porosity in the resin film is small, the effect of reducing the relative permittivity may be reduced, and if the content exceeds the upper limit, the porosity in the resin film is increased, The mechanical strength of the resin film may decrease. The decomposable component may be contained in the form of a copolymer even when it is simply mixed.

Examples of the thermosetting resin include phenolic novolac resins, bisphenol A novolac resins and other novolac phenolic resins, unmodified resole phenolic resins, oil-modified resol phenolic resins and other phenolic resins such as novolac epoxy resins, and novolac epoxy resins. , Novolak type epoxy resins such as cresol novolac epoxy resin, epoxy resins such as biphenyl type epoxy resin, resins having triazine ring such as urea (urea) resin, melamine resin, unsaturated polyester resin, bismaleimide resin, polyurethane resin, diallyl Phthalate resin, silicone resin, resin having benzoxazine ring, cyanate ester resin, polyimide resin, polyamide resin, polyamideimide resin, polyphenylquinoxaline resin, polybenzene Zone imidazole resin, polybenzothiazole resins, resins having a benzoxazine ring, such as benzoxazole resin. Among these, a resin having a benzoxazine ring (particularly a benzoxazole resin or a benzoxazole resin precursor) is preferable. Thereby, a resin film excellent in heat resistance and having a low dielectric constant can be obtained.
Further, the thermosetting resin and the decomposable component are not particularly limited, but are preferably copolymerized.

The benzoxazole resin (or its precursor, the same shall apply hereinafter) is not particularly limited, but includes a first repeating unit obtained by reacting a bisaminophenol compound having no functional group with a dicarboxylic acid having no functional group. Including. The functional group means a group capable of cross-linking the resin three-dimensionally.
The bisaminophenol compound having no functional group means an unsubstituted bisaminophenol compound, specifically 2,4-diamino-resorcinol, 2,5-diamino-1,4-dihydroxylbenzene, etc. Compounds having dihydroxylbenzene:
Compounds having dihydroxy-biphenyl such as 3,3′-diamino-4,4′-dihydroxy-biphenyl, 3,3′-dihydroxy-4,4′-diamino-biphenyl,
Compounds having dihydroxy-diphenyl ether such as 3,3′-diamino-4,4′-dihydroxy-diphenyl ether:
Compounds having a fluorene skeleton such as 9,9-bis (3-amino-4-hydroxy-phenyl) fluorene, 9,9-bis (4- (4-amino-3-hydroxy) -phenoxy-phenyl) fluorene:
Compounds having a binaphthalene skeleton such as 2,2′-bis- (4-amino-3-hydroxy-phenoxy) -1,1′-binaphthalene:
Examples thereof include compounds having a fluorine or fluorinated alkyl group such as 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane. Among these, one or more bisaminophenol compounds selected from a compound having dihydroxy-biphenyl, a compound having a fluorene skeleton, and a compound having a binaphthalene skeleton are preferable. Thereby, heat resistance can be improved especially. Furthermore, if a compound having a fluorene or binaphthalene skeleton is used, the solubility of the resin precursor is also excellent.

  The dicarboxylic acid having no functional group means an unsubstituted dicarboxylic acid. Specifically, isophthalic acid, terephthalic acid, 2-fluoroisophthalic acid, 2,3,5,6-tetrafluoroterephthalic acid, etc. Phthalic acid, 4,4′-biphenyldicarboxylic acid, 3,4′-biphenyldicarboxylic acid, 3,3′-biphenyldicarboxylic acid, 4,4′-bis (4-carboxyphenoxy) biphenyl, 4,4′- Biphenyl dicarboxylic acid such as bis (3-carboxyphenoxy) biphenyl, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, naphthalenedicarboxylic acid such as 2,6-naphthalenedicarboxylic acid, 4,4′-sulfonylbis Benzoic acid, 3,4′-sulfonylbisbenzoic acid, 3,3′-sulfonylbisbenzoic acid, 4,4′-oxybisbenzoic acid, 3,4′-oxybis Bisbenzoic acid such as benzoic acid, 3,3′-oxybisbenzoic acid, 2,2-bis (4-carboxyphenyl) propane, 2,2-bis (3-carboxyphenyl) propane, 2,2-bis ( Bis-carboxyphenyl-propane (hexafluoropropane) such as 4-carboxyphenyl) hexafluoropropane, 2,2-bis (3-carboxyphenyl) hexafluoropropane, 9,9-bis (4- (4-carboxyphenoxy) ) Phenyl) fluorene, 9,9-bis (4- (3-carboxyphenoxy) phenyl) fluorene, 9,9-bis- (2-carboxy-phenyl) fluorene, 9,9-bis- (3-carboxy-phenyl) ) Dicarboxylic acid having a fluorene skeleton such as fluorene, 4,4′-bis (4-carboxyphenoxy) -p-terphenyl, 4,4 ′ Examples include bis-carboxyphenyl-terphenyl such as -bis (4-carboxyphenoxy) -m-terphenyl, and these may be used alone or in combination of two or more. Among these, one or more dicarboxylic acids selected from terephthalic acid, isophthalic acid, biphenylcarboxylic acid, dicarboxylic acid having a fluorene skeleton, and the like are preferable. Thereby, solubility, toughness, and thermal decomposition resistance can be improved.

  Further, the benzoxazole resin may contain a bisaminophenol compound or a dicarboxylic acid in which one or both have a functional group. For example, 1) a benzoxazole resin containing a second repeating unit obtained by reacting a bisaminophenol compound having a functional group with a dicarboxylic acid having no functional group, and 2) a bisaminophenol compound having no functional group and a functional group. Benzoxazole resin containing a third repeating unit obtained by reacting a dicarboxylic acid having a group, and 3) a fourth product obtained by reacting a bisaminophenol compound having a functional group with a dicarboxylic acid having a functional group. Examples thereof include benzoxazole resins containing repeating units.

  The bisaminophenol compound having a functional group has a functional group capable of undergoing a crosslinking reaction in the molecule, and the functional group can undergo a three-dimensional crosslinking reaction when, for example, a benzoxazole resin is obtained. Is.

  Examples of the functional group constituting the bisaminophenol compound having the functional group include a functional group having an acetylene bond, a biphenylene group, a cyanato group, a maleimide group, a nadiimide group, a vinyl group, and a cyclopentadienyl group. Among these, a functional group having an acetylene bond is preferable. Thereby, the solubility to the solvent of a benzoxazole resin precursor can be improved. Furthermore, the heat resistance of the benzoxazole resin obtained from this benzoxazole resin precursor can also be improved.

Specific examples of the bisaminophenol compound having a functional group include 2,2′-bis- (3-hydroxy-4-aminophenoxy) -6,6′-bis-ethynyl-1,1′-binaphthalene, 2, Bisaminophenol compounds having ethynyl (phenylethynyl) -binaphthalene such as 2′-bis- (3-hydroxy-4-aminophenoxy) -6,6′-bis-phenylethynyl-1,1′-binaphthalene:
1,5-bis- (3-hydroxy-4-aminophenoxy) -2,6-bis-ethynyl-naphthalene, 1,5-bis- (3-hydroxy-4-aminophenoxy) -2,6-bis- Phenylethynyl-naphthalene), 1,5-bis- (3-hydroxy-4-aminophenoxy) -2-phenylethynylnaphthalene, 1,5-bis- (3-hydroxy-4-aminophenoxy) -3-phenylethynyl Bisaminophenol compounds having ethynyl (phenylethynyl) -naphthalene such as naphthalene:
9,9-bis-4- (3-hydroxy-4-aminophenoxy) phenyl-2,7-bis-ethynyl-fluorene, 9,9-bis-4- (3-hydroxy-4-aminophenoxy) phenyl- 2,7-bis-phenylethynyl-fluorene, 9,9-bis (3-amino-4-hydroxy-phenyl) -2,7-bis-ethynyl-fluorene, 9,9-bis (3-amino-4- Bisaminophenol compounds having ethynyl (phenylethynyl) -fluorene such as hydroxy-phenyl) -2,7-bis-phenylethynyl-fluorene,
1,3-bis- (3-hydroxy-4-aminophenoxy) -4-ethynyl-benzene, 1,3-bis- (3-hydroxy-4-aminophenoxy) -4-phenylethynyl-benzene, 1,4 Ethynyl (phenylethynyl) such as -bis- (3-hydroxy-4-aminophenoxy) -3-ethynyl-benzene, 1,4-bis- (3-hydroxy-4-aminophenoxy) -3-phenylethynyl-benzene A bisaminophenol compound having benzene:
3,3′-diamino-4,4′-dihydroxy-2-phenylethynyl-diphenyl ether, 3,3′-diamino-4,4′-dihydroxy-5-phenylethynyl-diphenyl ether, 3,3′-diamino-4 Bisaminophenol compounds having ethynyl (phenylethynyl) -diphenyl ether such as 4,4'-dihydroxy-6-phenylethynyl-diphenyl ether
3,3′-diamino-4,4′-dihydroxy-2-phenylethynyl-biphenyl, 3,3′-diamino-4,4′-dihydroxy-5-phenylethynyl-biphenyl, 3,3′-diamino-4 Bisaminophenol compounds having ethynyl (phenylethynyl) -biphenyl, such as 4,4'-dihydroxy-6-phenylethynyl-biphenyl:
3,3′-diamino-4,4′-dihydroxy-6,6′-diphenylethynyl-diphenylsulfone, 3,3′-dihydroxy-4,4′-diamino-6,6′-diphenylethynyl-diphenylsulfone, Bisaminophenol compounds having ethynyl (phenylethynyl) -diphenylsulfone, such as 3,3′-diamino-4,4′-dihydroxy-2,2′-diphenylethynyl-diphenylsulfone,
2,2-bis- (3-amino-4-hydroxy-6-ethynyl-phenyl) -propane, 2,2-bis- (3-amino-4-hydroxy-6-phenylethynyl-phenyl) -propane, 2 , 2-bis- (3-hydroxy-4-amino-6-phenylethynyl-phenyl) -propane, 2,2-bis- (3-amino-4-hydroxy-2-phenylethynyl-phenyl) -propane, etc. Bisaminophenol compounds having ethynyl (phenylethynyl) -phenyl-propane:
2,2-bis- (3-amino-4-hydroxy-6-ethynyl-phenyl) -hexafluoropropane, 2,2-bis- (3-amino-4-hydroxy-6-phenylethynyl-phenyl) -hexa Fluoropropane, 2,2-bis- (3-hydroxy-4-amino-6-phenylethynyl-phenyl) -hexafluoropropane, 2,2-bis- (3-amino-4-hydroxy-2-phenylethynyl- Examples thereof include bisaminophenol compounds having ethynyl (phenylethynyl) -phenyl-hexafluoropropane such as phenyl) -hexafluoropropane, and these may be used alone or in combination of two or more.
Among these, a bisaminophenol compound having at least one functional group selected from a bisaminophenol compound having ethynyl (phenylethynyl) -naphthalene and a bisaminophenol compound having ethynyl (phenylethynyl) -fluorene is preferable. Thereby, the elastic modulus at the time of high temperature of a benzoxazole resin can be improved.

  The dicarboxylic acid having a functional group has a functional group capable of undergoing a crosslinking reaction in the molecule, and the functional group can undergo a three-dimensional crosslinking reaction when, for example, a benzoxazole resin is obtained. is there.

  Examples of the functional group constituting the dicarboxylic acid having the functional group include a functional group having an acetylene bond, a biphenylene group, a cyanate group, a maleimide group, a nadiimide group, a vinyl group, and a cyclopentadienyl group. Examples of those having a functional group in the molecule include dicarboxylic acids having an acetylene skeleton in the molecule and dicarboxylic acids having a biphenylene skeleton. Among these, a functional group having an acetylene bond is preferable. Thereby, the heat resistance to the solvent of a benzoxazole resin precursor can be improved.

Specific examples of the dicarboxylic acid having a functional group include ethynylisophthalic acid such as 3-ethynylphthalic acid, 4-ethynylphthalic acid and 5-ethynylisophthalic acid, and ethynyl such as 2-ethynylterephthalic acid and 3-ethynylterephthalic acid. Ethinylphthalic acid such as terephthalic acid:
Ethynyl-naphthalenedicarboxylic acid such as 2-ethynyl-1,5-naphthalenedicarboxylic acid, 3-ethynyl-1,5-naphthalenedicarboxylic acid,
4,4'-diethynyl-2,2'-biphenyldicarboxylic acid, diethynyl-biphenyldicarboxylic acid such as 5,5'-diethynyl-2,2'-biphenyldicarboxylic acid,
Bis (carboxy-ethynylphenyl) propane such as 2,2-bis (2-carboxy-3-ethynylphenyl) propane, 2,2-bis (2-carboxy-4-ethynylphenyl) propane,
Bis (carboxy-ethynylphenyl) hexafluoropropane such as 2,2-bis (2-carboxy-4-ethynylphenyl) hexafluoropropane, 2,2-bis (3-carboxy-5-ethynylphenyl) hexafluoropropane: ,
Structural isomers of 4-ethynyl-1,3-dicarboxycyclopropane, 5-ethynyl-2,2-dicarboxycyclopropane, 1,3-bis (4-carboxy-phenoxy) -5-ethynyl-benzene, 1 , 3-bis (4-carboxy-phenyl) -5-ethynyl-benzene, (ethynyl-phenoxy) isophthalic acid such as 5- (3-ethynyl-phenoxy) -isophthalic acid, 2- (1-ethynyl) (Phenoxy) (ethynyl-phenoxy) terephthalic acid such as terephthalic acid (ethynyl-phenoxy) phthalic acid such as:
(Ethynyl-phenyl) -isophthalic acid such as 5- (1-ethynyl-phenyl) -isophthalic acid, (ethynyl-phenyl) -terephthalic acid such as (ethynyl-phenyl) -terephthalic acid (ethynyl- Phenyl) -phthalic acid:
Phenylethynylphthalic acid, such as phenylethynylphthalic acid, such as 3-phenylethynylphthalic acid, 5-phenylethynylisophthalic acid, phenylethynylphthalic acid, 2-phenylethynylterephthalic acid, 3-phenylethynylterephthalic acid, etc.
Phenylethynyl-naphthalenedicarboxylic acid such as 2-phenylethynyl-1,5-naphthalenedicarboxylic acid:
Diphenylethynyl-biphenyldicarboxylic acid such as 3,3′-diphenylethynyl-2,2′-biphenyldicarboxylic acid, and bis (carboxy-phenylethynyl) such as 2,2-bis (2-carboxy-3-phenylethynylphenyl) propane Bis (carboxy-phenylethynylphenyl) hexafluoropropane such as phenyl) propane, 2,2-bis (2-carboxy-4-phenylethynylphenyl) hexafluoropropane:
(Phenylethynyl-phenoxy) -isophthalic acid such as 5- (1-phenylethynyl-phenoxy) -isophthalic acid, 5- (2-phenylethynyl-phenoxy) -isophthalic acid, 5- (3-phenylethynyl-phenoxy) isophthalic acid Dicarboxylic acids having a phenylethynyl skeleton such as (phenylethynyl-phenoxy) phthalic acid such as (phenylethynyl-phenoxy) terephthalic acid such as acid, 2- (1-phenylethynyl-phenoxy) terephthalic acid,
3-hexynylphthalic acid, 2-hexynylterephthalic acid, 2-hexynyl-1,5-naphthalenedicarboxylic acid, 3,3′-dihexynyl-2,2′-biphenyldicarboxylic acid, 2,2-bis ( 2-carboxy-3-hexynylphenyl) propane, 2,2-bis (3-carboxy-5-hexynylphenyl) hexafluoropropane, 4-hexynyl-1,3-dicarboxycyclopropane, 1, Structural isomers of 3-bis (4-carboxy-phenoxy) -5-hexynyl-benzene, dicarboxylic acids having an alkyl group ethynyl group such as 5- (3-hexynyl-phenoxy) -isophthalic acid:
Dicarboxylic acid having an acetylene skeleton in the molecule such as 4,4′-transicarboxylic acid, 3,4′-transicarboxylic acid, and the like:
Examples include 1,2-biphenylene dicarboxylic acid, dicarboxylic acid having a biphenylene skeleton such as 1,3-biphenylene dicarboxylic acid, and the like. These may be used alone or in combination of two or more. Among these, at least one dicarboxylic acid selected from ethynylisophthalic acid, (ethynyl-phenoxy) isophthalic acid, phenylethynylphthalic acid, and (phenylethynyl-phenoxy) -isophthalic acid is preferable. Thereby, the heat resistance of the benzoxazole resin finally obtained can be further improved.

  As a method for obtaining a resin film composed of a curable resin containing such a decomposable component, for example, a varnish is prepared by dissolving the curable resin in an organic solvent, and this varnish is applied to an appropriate support. And a method for obtaining a resin film. Examples of the application method include dipping, screen printing, spraying, spin coater, and roll coating.

1A. Activation energy irradiation Examples of the activation energy include ultraviolet rays, electron beams, microwaves, ultrasonic waves, and infrared rays. Among these, ultraviolet rays or electron beams are preferable. Thereby, the curing reaction of the thermosetting resin and the decomposition reaction of the decomposable component can be efficiently controlled, and the shape and size of the fine pores can be maintained more uniformly.

  The irradiation time of the activation energy is not particularly limited, but is preferably 0.5 to 5 minutes, and particularly preferably 1 to 3 minutes. When the irradiation time is within the above range, the curing reaction of the thermosetting resin and the decomposition reaction of the decomposable component can be controlled more efficiently.

  The required irradiation intensity of the activation energy is not particularly limited, but depends on the type of activation energy, the type of thermosetting resin and the decomposable component, and the necessary activation energy irradiation amount can be reduced by heating. It is.

Furthermore, when ultraviolet rays are used as the activation energy, it may be possible to selectively cure the thermosetting resin and decompose the decomposable components by selecting an arbitrary wavelength as the ultraviolet rays to be irradiated. is there. Thereby, the thermodecomposable component can be decomposed while the thermosetting resin is sufficiently cured. Therefore, the structure of the resin film is fixed to some extent by the curing of the thermosetting resin, so that the micropores generated by the decomposition of the decomposable component can also be prevented from being deformed or disappeared. Specifically, when the thermosetting resin is cured, the wavelength of the ultraviolet rays to be irradiated varies depending on the type of the resin and is not particularly limited, but is preferably 300 to 500 nm, and particularly preferably 350 to 400 nm. By irradiating ultraviolet rays having a wavelength within the above range, the thermosetting resin can be efficiently cured.
Moreover, when decomposing | disassembling the said decomposable component, although the suitable wavelength changes with kinds of decomposable component and the wavelength of the ultraviolet-ray to irradiate is not specifically limited, 220-500 nm is preferable and 240-400 nm is especially preferable. The decomposable component can be efficiently decomposed by irradiating ultraviolet rays having a wavelength within the above range.

In addition, when the step of irradiating the activation energy is performed while heating (for example, 200 ° C. or higher), it is preferably performed in an inert gas atmosphere as in the case of the rapid heating step, although not particularly limited. Thereby, the dielectric constant can be particularly improved.
The concentration of the inert gas atmosphere in this case is not particularly limited, but an oxygen concentration of 300 ppm or less is preferable, and 20 to 100 ppm is particularly preferable. Thereby, the dielectric constant can be particularly improved. If the oxygen concentration exceeds the upper limit, the effect of lowering the dielectric constant may be reduced. Moreover, production efficiency may fall that the said oxygen concentration is less than the said lower limit. That is, it may take a long time to make the oxygen concentration less than the lower limit.

The decomposition amount of the decomposable component in the step of irradiating the activation energy is not particularly limited, but is preferably 20% or more of the decomposable component contained in the resin, and particularly preferably 25 to 40%. . If the amount of decomposition is less than the lower limit, the decomposable component removal efficiency in the cleaning is lowered, the fine pores may be crushed and the effect of forming the fine pores may be reduced, exceeding the upper limit The curing reaction of the thermosetting resin may not catch up, and the effect of forming micropores may be reduced.
The decomposition amount can be evaluated, for example, by measuring the weight loss during heating by TG / DTA. Specifically, using TG / DTA, a change in weight was measured while raising the temperature from 30 ° C. to 500 ° C. at a rate of temperature rise of 10 ° C./min in a dry nitrogen stream at 200 mL / min, and calculated from the following formula: it can.
The decomposition amount of the decomposable component before and after the step of irradiating the activation energy is determined by the formula (1).
Decomposition amount (%) = (decomposable component content 1 (%) − degradable component content 2 (%)) / degradable component content 1 (%) (1)
Here, the content 1 of the decomposable component is the content of the decomposable component before irradiating the activation energy, and the content 2 of the decomposable component is the content of the decomposable component after irradiating the activation energy. Indicates.
Here, the content of the decomposable component contained in the resin film before and after the step of irradiating the activation energy can be obtained by Expression (2).
Content of degradable component (%) = (Wa−Wb) / Wa × 100 (2)
Here, Wa represents the resin weight at 200 ° C., and Wb represents the resin weight at 450 ° C.

The degree of cure of the thermosetting resin in the step of irradiating the activation energy is not particularly limited, but is preferably 30% or more, and particularly preferably 40 to 80%. If the degree of cure is less than the lower limit, the effect of forming uniform micropores may be reduced, and there is no particular problem even if the upper limit is exceeded, but it takes a long time to produce a porous resin film. As a result, productivity may decrease.
The degree of cure can be evaluated, for example, by measuring the infrared absorption wavelength of the resin film. Specifically, it is calculated from the following formula using an infrared absorption spectrometer.
Curing degree = (Abs1-Abs2) / Abs1
Here, Abs1 indicates the absorbance of the functional group before irradiation of activation energy, and Abs2 indicates the absorbance of the functional group after irradiation of activation energy.

2A. Cleaning In step A, the resin film is cleaned after irradiating the resin film with activation energy. Thereby, the decomposable component can be easily removed. In addition, the heat treatment step (3A) can be shortened. Furthermore, the temperature of the heat treatment step (3A) can be performed at a low temperature. If the heat treatment step (3A) can be performed at a low temperature, damage to the semiconductor wiring can be reduced.
The reason why the heat treatment step can be shortened and reduced in temperature by the washing step (2A) is considered as follows.
Usually, in order to complete the decomposition of the decomposable component, it is necessary to perform the heat treatment step at a high temperature or for a long time. However, in the present invention, by reducing the amount of residual decomposable components in the resin film by the washing step (2A), the burden of the heat treatment step can be reduced, and the temperature can be lowered and the time can be shortened.

Examples of the step of cleaning the resin film include wet cleaning methods such as a method of immersing the resin film in a cleaning liquid and a method of spraying a cleaning liquid onto the resin film. Among these, a wet cleaning method in which the resin film is immersed in a cleaning liquid is preferable. This effectively removes decomposition components, lowers the temperature of the heat treatment step, shortens the time of the heat treatment step, and further generates a trace amount during post-heating (for example, after coating on a semiconductor wafer). Minutes can be reduced.
Examples of the cleaning liquid include 2-propanol, propylene glycol propyl ether, cyclohexanone, cyclopentanone, γ-butyllactone, n-methyl-2pyrrolidone, toluene, 1,2-dichloroethane, 1,4-dioxane, 1-nitro. Propane, 2-nitropropane, acetone, acetonitrile, benzene, caprolactone, chloroform, cyclohexanone, diethylene glycol monomethyl ether acetate, diglyme, dimethyl sulfoxide, dimethylformamide, ethyl acetate, ethylene glycol monoether acetate, methyl acetate, methyl ethyl ketone, methylene Chloride, monoglyme, n-propyl acetate, propionitrile, propylene carbonate, propylene oxa De, styrene, tetrahydrofuran, trichlorethylene, triglyme, and organic solvents such as vinyl acetate. These cleaning liquids are appropriately used depending on the combination of the thermosetting resin and the decomposable component.

Specific examples of the method of immersing the resin film in a cleaning liquid include a method of immersing the resin film in a cleaning liquid such as 2-propanol or propylene glycol propyl ether at 15 to 70 ° C. for 10 to 120 minutes.
In addition, as a method of spraying the cleaning liquid onto the resin film, a single wafer spray cleaning method similar to that normally used when cleaning deposits after the etching process of the semiconductor wafer, the semiconductor wafer on the coater For example, a method of spray cleaning so that the cleaning liquid can be spread over the entire resin film using the same equipment for rinsing the edge. At this time, the cleaning liquid may be sprayed while rotating the semiconductor wafer.
For example, when washing on a coater, the following conditions are preferable. The flow rate of the cleaning liquid is not particularly limited, but is preferably 10 to 200 ml / min, and particularly preferably 30 to 100 ml / min. Further, when the semiconductor wafer is cleaned while rotating, the number of rotations is not particularly limited, but is preferably 300 to 2,500 rpm, and particularly preferably 500 to 1,500 rpm. The washing time is not particularly limited, but is preferably 1 to 10 minutes, and particularly preferably 2 to 5 minutes.
More specifically, it is preferable that the cleaning liquid is spun off by rotating at a rotational speed of 1,500 to 2,500 rpm for 1 to 5 minutes without spraying the cleaning liquid after cleaning, and particularly at a speed of 2,000 to 2,500 rpm. It is preferable that the cleaning solution is shaken off by rotating for 2 to 3 minutes. Furthermore, you may heat-dry at about 50-200 degreeC for about 1 to 3 minutes. This washing step may be repeated several times as necessary.

Moreover, although the said washing | cleaning process (2A) is not specifically limited, It is preferable that the residue of the said decomposable component is removed with a washing | cleaning liquid. Thereby, the temperature reduction of the said heat processing process and the shortening of the said heat processing time can be achieved.
The cleaning liquid is not particularly limited as long as it dissolves the decomposable component and does not dissolve the thermosetting resin. Specific examples include organic solvents such as 2-propanol, propylene glycol propyl ether, cyclohexanone, γ-butyl lactone, n-methyl-2pyrrolidone, and toluene.
In addition, the residue may include not only those after decomposition of the decomposable component but also those remaining without decomposing the decomposable component.

3A. Heat treatment In step A, the resin film is washed and then heat treated. Thereby, the curing degree of the thermosetting resin can be adjusted, and thereby the characteristics of the resin film can be stabilized. In addition, the decomposable component can be reliably decomposed, thereby facilitating the formation of uniform-sized micropores.
The heat treatment step (3A) is not particularly limited as long as it is a temperature that accelerates the curing of the thermosetting resin. Specifically, heat treatment is preferably performed at 200 to 400 ° C. for 30 to 120 minutes, and particularly preferably 300 to 350 ° C. for 45 to 90 minutes. When the heat treatment condition is within the above range, damage to the semiconductor wiring can be particularly prevented.

The heat treatment method may be the same as the rapid heating method, but a different method is preferred. Specific examples include a method of heating in a furnace, oven, vacuum oven or the like.
In addition, although the process to heat-process is not specifically limited, It is preferable to perform in inert gas atmosphere similarly to the process of the said rapid heating. Thereby, the dielectric constant can be particularly improved.
The concentration of the inert gas atmosphere in this case is not particularly limited, but an oxygen concentration of 300 ppm or less is preferable, and 20 to 100 ppm is particularly preferable. Thereby, the dielectric constant can be particularly improved. If the oxygen concentration exceeds the upper limit, the effect of lowering the dielectric constant may be reduced. Moreover, production efficiency may fall that the said oxygen concentration is less than the said lower limit. That is, it may take a long time to be less than the lower limit of the oxygen concentration.

A porous resin having uniform fine pores can be obtained by the steps as described above.
In this embodiment, the resin film has the activation energy irradiation step (1A), the cleaning step (2A), and the heat treatment step (3A). However, the present invention is not limited to this. .
For example, when a porous resin film is produced only by the step (1A) of irradiating the resin film with activation energy, the resin film is porous by the step (1A) of irradiating the resin film with activation energy and the step (2A) of washing. In the case of producing a porous resin film, there may be mentioned a case where a porous resin film is produced by the step (1A) of irradiating the resin film with activation energy and the step of heat treatment (3A).
Moreover, you may provide the rapid heating process (1B) mentioned later before or after the process (1A) of irradiating the activation energy. Thereby, the curing of the thermosetting resin and the decomposition of the decomposable component may be allowed to proceed to some extent by rapid heating, so that the heat treatment step can be further shortened or the micropores of uniform size can be obtained. Can be formed.
Further, another step may be provided between the steps, and the step (1A) for irradiating activation energy, the step (2A) for cleaning, and the step (3A) for heat treatment are performed a plurality of times. May be.

Next, the B step (FIG. 2), which is another preferred embodiment of the method for producing a porous resin film of the present invention, will be described.
In step B, a step (1B) of rapidly heating a resin film made of a thermosetting resin containing a decomposable component, a step (2B) of irradiating the resin film with activation energy, and cleaning the resin film And a step (4B) of heat-treating the resin film. Thereby, a resin film having uniform and fine holes can be obtained.

1B. Rapid heating In step B, the resin film is rapidly heated before irradiation with activation energy. In the rapid heating step (1B), the decomposable component is decomposed and the thermosetting resin is cured. Thereby, a porous resin film can be formed without the micropores generated by the decomposition of the decomposable component disappearing or deforming.
The reason why the porous resin film can be formed by rapidly heating the resin film without annihilation / deformation of the fine pores is as follows.
By rapidly heating the resin film, the thermodecomposable component is decomposed in a state in which the thermosetting resin is sufficiently cured. Therefore, the structure of the resin film is fixed to some extent by the curing of the thermosetting resin, so that the micropores generated by the decomposition of the decomposable component can also be prevented from being deformed or disappeared.

  The temperature increase rate of the resin film in the rapid heating step is not particularly limited, but is preferably equal to or higher than the temperature at which the thermosetting resin is rapidly cured. More specifically, the rate of temperature rise of the resin film in the rapid heating step is not particularly limited, but is preferably 50 ° C./min or more, and particularly preferably 200 to 300 ° C./min. When the rate of temperature rise is less than the lower limit, the thermosetting resin may be insufficiently cured, and even if the upper limit is exceeded, there is no change in the effect of forming micropores. If the thermosetting resin is not sufficiently cured, uniform micropores may not be formed, and the effect of reducing the dielectric constant may be reduced.

  The heating temperature of the resin film in the rapid heating step is not particularly limited, but is preferably 200 to 400 ° C, particularly preferably 250 to 350 ° C. When the heating temperature is less than the lower limit, curing of the thermosetting resin and decomposition of the decomposable component may not proceed sufficiently, and when exceeding the upper limit, generation of voids, damage to semiconductor wiring, etc. may occur. There is.

The rapid heating process may be performed when all of the heating process is rapidly heated or when a part of the heating process is rapidly heated. The case where the part is rapidly heated is a case where the part is rapidly heated at the beginning, middle or last part of the heating process.
Furthermore, it is preferable that the rapid heating rapidly heats the range of the decomposition start temperature of the decomposable component constituting the resin film and the thermosetting temperature of the thermosetting resin. Specifically, it is preferable to rapidly heat a range in which the temperature of the resin film is 80 to 300 ° C, and it is particularly preferable to rapidly heat a range in which the temperature is 100 to 200 ° C. When the inside of the temperature range is rapidly heated, the micropores generated by the decomposition of the decomposable component can be particularly suppressed from being deformed / disappeared.

The rapid heating step is not particularly limited, but is preferably performed in an inert gas atmosphere. Thereby, the dielectric constant can be particularly improved.
Further, the concentration of the inert gas atmosphere is not particularly limited, but an oxygen concentration of 300 ppm or less is preferable, and 20 to 100 ppm is particularly preferable. Thereby, the dielectric constant can be particularly improved. If the oxygen concentration exceeds the upper limit, the effect of lowering the dielectric constant may be reduced. Moreover, production efficiency may fall that the said oxygen concentration is less than the said lower limit. That is, it may take a long time to be less than the lower limit of the oxygen concentration.
Examples of the inert gas include nitrogen gas and argon gas.

  Examples of the rapid heating method include a rapid heating method on a hot plate such as a hot plate and a rapid heating method by irradiation with an infrared lamp. These methods can be used alone or in combination. Among these, the method of rapid heating on a hot plate is preferable. Thereby, hardening of the said thermosetting resin can be advanced preferentially.

  In the rapid heating step, it is preferable to supply heat uniformly to the resin film. For example, it is preferable to use a ceramic heater or a mica heater for the hot plate, and it is more preferable that the hot plate is made of ceramic. The ceramic heater is preferably a pulse heater. Thereby, temperature variation can be reduced more.

Although the decomposition amount of the decomposable component in the rapid heating step is not particularly limited, it is preferably 20% or more of the decomposable component contained in the resin, particularly preferably 25 to 40%. If the amount of decomposition is less than the lower limit, the decomposable component removal efficiency in the cleaning is lowered, the fine pores may be crushed and the effect of forming the fine pores may be reduced, exceeding the upper limit The curing reaction of the thermosetting resin may not catch up, and the effect of forming micropores may be reduced.
The decomposition amount can be evaluated, for example, by measuring the weight loss during heating by TG / DTA. Specifically, using TG / DTA, a change in weight was measured while raising the temperature from 30 ° C. to 500 ° C. at a rate of temperature rise of 10 ° C./min in a dry nitrogen stream at 200 mL / min, and calculated from the following formula: it can.
The amount of decomposition of the decomposable component before and after the rapid heating step is determined by the formula (1).
Decomposition amount (%) = (decomposable component content 1 (%) − degradable component content 2 (%)) / degradable component content 1 (%) (1)
Here, the content 1 of the decomposable component indicates the content of the decomposable component before the rapid heating, and the content 2 of the degradable component indicates the content of the degradable component after the rapid heating.
Here, the content of the decomposable component contained in the resin film before and after the rapid heating step can be obtained by the formula (2).
Content of degradable component (%) = (Wa−Wb) / Wa × 100 (2)
Here, Wa represents the resin weight at 200 ° C., and Wb represents the resin weight at 450 ° C.

The degree of cure of the thermosetting resin in the rapid heating step is not particularly limited, but is preferably 30% or more, and particularly preferably 40 to 80%. If the degree of cure is less than the lower limit, the effect of forming uniform micropores may be reduced, and there is no particular problem even if the upper limit is exceeded, but it takes a long time to produce a porous resin film. As a result, productivity may decrease.
The degree of cure can be evaluated, for example, by measuring the infrared absorption wavelength of the resin film. Specifically, it is calculated from the following formula using an infrared absorption spectrometer.
Curing degree = (Abs1-Abs2) / Abs1
Here, Abs1 indicates the absorbance of the functional group before rapid heating, and Abs2 indicates the absorbance of the functional group after rapid heating.

2B. Activation energy irradiation In step B, activation energy is irradiated to the resin film as described above.
The step (2B) of irradiating the activation energy is the same as 1A.

3B. Cleaning In step B, the resin film is cleaned after being irradiated with the activation energy.
The washing step (3B) is the same as 2A.

4B. Heat treatment In step B, the resin film is washed and then heat treated.
The step (4B) of heat treatment is the same as 3A.

A porous resin having uniform fine pores can be obtained by the steps as described above.
In the present embodiment, the resin film is rapidly heated (1B), activated energy irradiated (2B), washed (3B), and heat treated (4B). Although it had, it is not limited to this.
For example, when a porous resin film is manufactured by the step (1B) of rapidly heating the resin film and the step (2B) of irradiating activation energy, the step (1B) of rapidly heating the resin film and the activation energy are used. When a porous resin film is produced by the irradiation step (2B) and the washing step (3B), the resin film is rapidly heated (1B), the activation energy irradiation step (2B), and the heat treatment step. The case where a porous resin film is manufactured with (4B) is mentioned.
Further, the order of the steps is not particularly limited. For example, the steps of rapid heating (1B), cleaning (3B), irradiation with activation energy (2B), and heat treatment (4B) are performed in this order. In this case, there may be mentioned a case where the rapid heating step (1B), the heat treatment step (4B), the cleaning step (3B), and the activation energy irradiation step (2B) are performed in this order.
Further, other steps such as heat insulation (cooling) may be provided between the steps, a step of rapid heating (1B), a step of irradiating activation energy (2B), and a step of cleaning (3B) The heat treatment step (4B) may be performed a plurality of times.
Further, the step (2B) of irradiating the activation energy may be performed during the step (1B) of rapid heating and the step of heat treatment (4B). Thus, when the thermal energy such as rapid heating and heat treatment and the activation energy are simultaneously applied to the resin film, the activation energy irradiation amount can be kept low and the irradiation time can be shortened. .

  The porosity of the porous resin film obtained by the method as described above is not particularly limited, but is preferably 10% or more, and particularly preferably 15 to 50%. When the porosity is less than the lower limit, the effect of improving the dielectric constant of the resin film may be reduced, and when the porosity exceeds the upper limit, the strength of the resin film may be reduced.

  The average pore diameter of the porous resin film is not particularly limited, but is preferably 20 nm or less, and particularly preferably 5 nm or less. When the average pore diameter exceeds the upper limit, the mechanical strength of the porous resin film may be reduced, or when used in a semiconductor element, the insulating property may be reduced.

  The thickness of the porous resin film is not particularly limited, but is preferably 0.05 to 100 μm, particularly preferably 0.1 to 50 μm, and most preferably 0.2 to 20 μm. When the thickness is within the above range, the fine uniformity of the pore structure and the mechanical strength of the porous resin film are particularly excellent.

  The porous resin film obtained by the above-mentioned method is, for example, a semiconductor interlayer insulating film or surface protective film, a multilayer circuit interlayer insulating film, a flexible copper-clad plate cover coat, a solder resist film, a liquid crystal alignment film, an etching It can be suitably used for a protective film (etching stopper) and the like. Among these, it is particularly preferably used as an interlayer insulating film and a surface protective film for semiconductors.

Next, the semiconductor device of the present invention will be described based on a preferred embodiment.
FIG. 3 is a cross-sectional view schematically showing an example of the semiconductor device of the present invention.
The semiconductor device 100 includes a semiconductor substrate 1 on which elements are formed, a silicon nitride film 2 provided on the upper side of the semiconductor substrate 1 (upper side in FIG. 1), and a porous resin film 3 provided on the silicon nitride film 2. And a copper wiring layer 4 covered with a barrier layer 6.
The porous resin film 3 has a recess corresponding to the pattern to be wired, and a copper wiring layer 4 is provided in the recess.
In the porous resin film 3, nanofoams (micropores) (not shown) are formed.
In addition, a modified treatment layer 5 is provided between the porous resin film 3 and the copper wiring layer 4.
A hard mask layer 7 is formed on the upper side of the porous resin film 3 (on the side opposite to the silicon nitride film 2).

Although the semiconductor device 100 using the porous resin film 3 has been described in the present embodiment, the present invention is not limited to this.
In the present invention, the porous resin film 3 functions as an interlayer insulating film.

Since the semiconductor device of the present invention uses the porous resin film as described above, it is excellent in dimensional accuracy and can sufficiently exhibit insulation, thereby being excellent in connection reliability.
Moreover, since the porous resin film as described above has excellent adhesion to the wiring layer, the connection reliability of the semiconductor device can be further improved.
In addition, since the porous resin film as described above has excellent dielectric characteristics, signal loss of the semiconductor device can be reduced.
In addition, since the porous resin film as described above is excellent in dielectric characteristics, wiring delay can be reduced.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example and a comparative example, this invention is not limited to this.

(Example 1)
1. Production of Resin Film Using poly (propylene glycol) bis (2-aminopropyl ether) (manufactured by Aldrich, number average molecular weight: about 4,000, decomposition temperature: about 330 ° C.) as a decomposable component, What was obtained by the following synthesis | combination was used.
(Synthesis of curable resin)
24.5 g (0.095 mol) of 2,2-bis (3-amino-4-hydroxyphenyl) propane was dissolved in 330 mL of dry N-methyl-2-pyrrolidone, and 5-ethynylisophthalic acid dichloride 22 was dissolved in this solution. 0.7 g (0.1 mol) was added at 10 ° C. under dry nitrogen, followed by stirring at 10 ° C. for 1 hour and subsequently at 20 ° C. for 1 hour. After cooling to 10 ° C., 22.3 g (0.22 mol) of triethylamine was added, and then 40.0 g of poly (propylene glycol) bis (2-aminopropyl ether) as a decomposable component was added to 100 mL of γ-butyrolactone. 0.01 mol) was added at 10 ° C. under dry nitrogen, and then stirred at 10 ° C. for 1 hour and then at 20 ° C. for 20 hours.
After completion of the reaction, the reaction solution is filtered to remove triethylamine hydrochloride, and the filtered solution is dropped into a mixed solution of 6.6 L of ion-exchanged water and 6.6 L of isopropanol, and the precipitate is collected and dried. Thus, 75.2 g of a curable resin (polybenzoxazole resin) in which a decomposable component was copolymerized was obtained.
When the molecular weight of the obtained curable resin was calculated in terms of polystyrene using GPC manufactured by Tosoh Corporation, the weight average molecular weight was 22,800 and the molecular weight distribution was 2.10. The content of the decomposable component by TG / DTA was 39% by weight.

(Coating varnish adjustment)
The above-mentioned curable resin (5.00 g) was dissolved in N-methyl-2-pyrrolidone (20.00 g) and filtered through a Teflon (R) filter having a pore diameter of 0.2 μm to obtain a coating varnish.

(Manufacture of resin film)
The above coating varnish was applied onto a silicon wafer by a spin coater. At this time, the rotation speed and time of the spin coater were set so that the thickness of the resin film after the heat treatment was about 0.3 μm. The resin film of curable resin was obtained by drying for 4 minutes on a 90 degreeC hotplate after application | coating.

2. Rapid heating process The above-mentioned resin film (the state formed on the silicon wafer) is measured at 350 ° C. in a nitrogen atmosphere in which the oxygen concentration is controlled to 100 ppm or less by inflow of nitrogen. As described above, rapid heating treatment was performed for 3 minutes on a hot plate heated in advance. Here, the temperature rising rate of the resin film was 200 ° C./min.
The degree of cure of the thermosetting resin constituting the resin film here was 60%, and the amount of decomposition of the decomposable component was 30%.

3. Step of irradiating activation energy Next, the measured temperature of the silicon wafer is 250 under the nitrogen atmosphere in which the above-described resin film (formed on the silicon wafer) is controlled to have an oxygen concentration of 100 ppm or less by flowing nitrogen. When placed on a hot plate that has been heated to a temperature of 5 ° C., ultraviolet rays (high pressure mercury lamp, wavelength 220 to 600 nm, illuminance 800 mW (240 to 320 nm)) are simultaneously irradiated, and activation energy irradiation treatment is performed for 5 minutes. It was.

(Example 2)
The same procedure as in Example 1 was conducted except that the heating rate and heating time of the rapid heating step and the activation energy irradiation time were as follows.
In the step of rapid heating, the hot plate was heated so that the measured temperature of the silicon wafer was 330 ° C., and the rapid heating treatment time was 5 minutes. Here, the temperature rising rate of the resin film was 190 ° C./min. Further, the activation energy irradiation treatment was performed for 7 minutes.

(Example 3)
The same procedure as in Example 1 was carried out except that the rapid heating step was not performed and the washing step and the heat treatment step described below were added.
4). Cleaning process Place the above-mentioned resin film (formed on the silicon wafer) on a spin coater to perform cleaning treatment by spraying 2-propanol while rotating at 800 rpm for 5 minutes, and then adhere to the resin film at 2,500 rpm The 2-propanol was shaken off and dried on a hot plate at 200 ° C. for 2 minutes.

5). Next, the above-mentioned resin film (the state formed on the silicon wafer) is put in a 25 ° C. oven in which the oxygen concentration is controlled to 100 ppm or less by inflow of nitrogen, and the temperature is increased by 10 ° C./min. The temperature was raised to 350 ° C. at a rate, and a heat treatment was carried out at 350 ° C. for 60 minutes, and a porous resin film was obtained on a silicon wafer.

Example 4
The same procedure as in Example 1 was performed except that a heat treatment step described below was added.
5). Next, the above-mentioned resin film (the state formed on the silicon wafer) is put in a 25 ° C. oven in which the oxygen concentration is controlled to 100 ppm or less by inflow of nitrogen, and the temperature is increased by 10 ° C./min. The temperature was raised to 350 ° C. at a rate, and heat treatment was performed at 350 ° C. for 15 minutes as it was, and then a porous resin film was obtained on a silicon wafer.

(Example 5)
The procedure was the same as in Example 1 except that the activation energy irradiation time was changed and a cleaning step described below was added.
The irradiation time of activation energy was 3 minutes.
4). Cleaning process Place the above-mentioned resin film (formed on the silicon wafer) on a spin coater to perform cleaning treatment by spraying 2-propanol while rotating at 800 rpm for 5 minutes, and then adhere to the resin film at 2,500 rpm The 2-propanol was shaken off and dried on a hot plate at 200 ° C. for 2 minutes.

(Example 6)
The same procedure as in Example 1 was performed except that the rapid heating step was not performed and a heat treatment step described below was added.
5). Next, the above-mentioned resin film (the state formed on the silicon wafer) is put in a 25 ° C. oven in which the oxygen concentration is controlled to 100 ppm or less by inflow of nitrogen, and the temperature is increased by 10 ° C./min. The temperature was raised to 350 ° C. at a rate, and a heat treatment was performed at 350 ° C. for 90 minutes as it was to obtain a porous resin film on a silicon wafer.

(Example 7)
The same procedure as in Example 1 was performed except that the treatment time for irradiating activation energy was changed without performing the rapid heating step, and the washing step described below was added.
The activation energy irradiation time was 20 minutes.
4). Cleaning process Place the above-mentioned resin film (formed on the silicon wafer) on a spin coater to perform cleaning treatment by spraying 2-propanol while rotating at 800 rpm for 5 minutes, and then adhere to the resin film at 2,500 rpm The 2-propanol was shaken off and dried on a hot plate at 200 ° C. for 2 minutes.

(Example 8)
Except that the step of irradiating the activation energy was performed before the step of rapid heating, the procedure was the same as in Example 1.

Example 9
The same procedure as in Example 1 was performed except that the rapid heating temperature was 300 ° C. and the treatment time in the step of irradiating the activation energy was 10 minutes.
Here, the heating rate of the resin film in the rapid heating process was 180 ° C./min. The degree of cure of the thermosetting resin constituting the resin film was 55%, and the degradation amount of the decomposable component was 25%.

(Example 10)
The same procedure as in Example 1 was performed except that the temperature for rapid heating and the time for irradiation with activation energy were changed and a washing step and a heat treatment step described below were added.
The rapid heating temperature was 250 ° C., and the activation energy irradiation time was 3 minutes. Here, the temperature rising rate of the resin film was 170 ° C./min.

4). Cleaning process Place the above-mentioned resin film (formed on the silicon wafer) on a spin coater to perform cleaning treatment by spraying 2-propanol while rotating at 800 rpm for 5 minutes, and then adhere to the resin film at 2,500 rpm The 2-propanol was shaken off and dried on a hot plate at 200 ° C. for 2 minutes.

5). Next, the above-mentioned resin film (the state formed on the silicon wafer) is put in a 25 ° C. oven in which the oxygen concentration is controlled to 100 ppm or less by inflow of nitrogen, and the temperature is increased by 10 ° C./min. The temperature was raised to 350 ° C. at a rate, and a heat treatment was carried out at 350 ° C. for 60 minutes, and a porous resin film was obtained on a silicon wafer.

(Example 11)
The same procedure as in Example 1 was performed except that the curable resin described below was used.
(Synthesis of curable resin)
60.0 g (0.17 mol) of 4,4-diaminodiphenylmethane bismaleimide was dissolved in 330 mL of dried N-methyl-2-pyrrolidone, and the poly (propylene glycol) bis (2- A solution obtained by dissolving 40.0 g (0.01 mol) of aminopropyl ether in 100 mL of γ-butyrolactone was added at 10 ° C. under dry nitrogen, and then stirred at 100 ° C. for 1 hour.
After completion of the reaction, the reaction solution is filtered, and the filtrate is added dropwise to a mixed solution of 6.6 L of ion exchange water and 6.6 L of isopropanol, and the precipitate is collected and dried to copolymerize the decomposable component. 78.5 g of curable resin (polyimide resin) was obtained.
The molecular weight of the obtained curable resin was measured using G.M. manufactured by Tosoh Corporation. P. C. The weight average molecular weight was 20,500 and the molecular weight distribution was 2.00. The content of the decomposable component by TG / DTA was 38% by weight.

(Example 12)
The same procedure as in Example 1 was carried out except that poly (n-hexylene) carbonate diol (manufactured by Sun Techno Chemical Co., RABECARRB106) was used as the decomposable component.

(Comparative Example 1)
Example 1 was performed except that the rapid heating step and the step of irradiating activation energy were not performed.

(Comparative Example 2)
Example 1 was repeated except that no degradable component was added.

The following evaluation was performed about the porous resin film obtained by each Example and the comparative example. The evaluation items are shown together with the contents. The obtained results are shown in Table 1.
1. Porosity For porosity (%), the density of the porous resin film obtained by total reflection X-ray was obtained, and the porosity was calculated by comparison with the density of the resin film having no pores.

2. Void size distribution and average pore size Void size distribution and average pore size (nm) were measured by small angle X-ray scattering (SAXS). A spherical model was used for the analysis, and the normalized dispersion value and the average pore diameter were calculated assuming that the pore size distribution follows the gamma distribution function.

3. Relative permittivity The relative permittivity was measured using a HP-4284A Precision LCR meter manufactured by Hewlett-Packard Co. at a frequency of 1 MHz in accordance with JIS-K6911.

4). Heat resistance Heat resistance was measured by using a TG / DTA6200 manufactured by Seiko Instruments Inc. under a nitrogen gas flow of 200 mL / min. .

5). Productivity Productivity is based on the man-hour (time) for producing the porous resin film obtained in Comparative Example 1 as a reference (100), compared with the man-hours of porous resin films obtained in other Examples and Comparative Examples. evaluated.

As is clear from Table 1, Examples 1 to 12 had a low dielectric constant, excellent heat resistance, and excellent productivity.
Moreover, since Examples 1-12 had a small average hole diameter and the normalized dispersion | distribution value of a hole size was low, it was shown that it has a fine and uniform hole.
Moreover, Examples 1-12 had a moderate porosity of about 30%.

  Next, the interlayer insulating film and the semiconductor device will be described.

(Examples 1A to 12A)
The porous resin film formed on the silicon wafer obtained in Examples 1 to 12 was used as an interlayer insulating film.
Next, a metal wiring was formed so as to form a predetermined pattern on the interlayer insulating film, thereby obtaining a semiconductor device.

(Comparative Examples 1A and 2A)
The porous resin film formed on the silicon wafer obtained in Comparative Examples 1 and 2 was used as an interlayer insulating film.
Next, a metal wiring was formed so as to form a predetermined pattern on the interlayer insulating film, thereby obtaining a semiconductor device.

The wiring delay rate was evaluated for the obtained semiconductor device.
The degree of wiring delay between the semiconductor devices obtained in Examples 1A to 12A and a semiconductor device having a SiO ₂ insulating film with the same configuration as this semiconductor device was compared. As the evaluation standard, the signal delay time obtained by conversion from the transmission frequency of the ring oscillator was adopted. As a result of comparing the two, it was confirmed that in the semiconductor device obtained by the present invention, the wiring delay was small and the speed was improved by about 18 to 25%.

It is process drawing which shows an example of the manufacturing method of the porous resin film of this invention. It is process drawing which shows an example of the manufacturing method of the porous resin film of this invention. It is sectional drawing which shows typically an example of the semiconductor device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Silicon nitride film 3 Porous resin film 4 Copper wiring layer 5 Modification process layer 6 Barrier layer 7 Hard mask layer 100 Semiconductor device

Claims (19)

  A method for producing a porous resin film comprising a step of irradiating activation energy to a resin film composed of a thermosetting resin containing a decomposable component, wherein the decomposable component is applied in the step of irradiating the activation energy. The method for producing a porous resin film is characterized by performing decomposition of the thermosetting resin and curing the thermosetting resin.   The method for producing a porous resin film according to claim 1, further comprising a step of washing the resin film after the step of irradiating the activation energy.   The method for producing a porous resin film according to claim 1, wherein the activation energy is an electron beam or an ultraviolet ray.   The method for producing a porous resin film according to any one of claims 1 to 3, further comprising a step of heat-treating the resin film after the step of irradiating the activation energy.   The method for producing a porous resin film according to claim 4, wherein the washing step is performed before the heat treatment step or after the heat treatment step.   The method for producing a porous resin film according to any one of claims 2 to 5, wherein in the cleaning step, the residue of the decomposable component is removed with a cleaning liquid.   The method for producing a porous resin film according to claim 1, wherein the decomposable component is a degradable oligomer.   The method for producing a porous resin film according to claim 7, wherein the decomposable oligomer is a thermally decomposable oligomer.   The method for producing a porous resin film according to claim 8, wherein the thermally decomposable oligomer is polyoxyalkylene.   The method for producing a porous resin film according to any one of claims 1 to 9, wherein the resin film is a copolymer of the decomposable component and a thermosetting resin.   The method for producing a porous resin film according to claim 10, wherein the thermosetting resin contains a benzoxazole resin and / or a benzoxazole resin precursor.   12. The method for producing a porous resin film according to claim 1, wherein the step of irradiating the activation energy is performed in an inert gas atmosphere.   The method for producing a porous resin film according to claim 12, wherein the oxygen concentration in the inert gas atmosphere is 300 ppm or less.   The method for producing a porous resin film according to any one of claims 1 to 13, wherein the step of irradiating the activation energy decomposes the decomposable component by 20% or more.   The method for producing a porous resin film according to any one of claims 1 to 14, wherein the step of irradiating the activation energy sets the degree of cure of the thermosetting resin to 30% or more.   The method for producing a porous resin film according to claim 1, wherein the porosity of the porous resin film is 10% or more.   The method for producing a porous resin film according to any one of claims 1 to 16, wherein an average pore diameter of the porous resin film is 20 nm or less.   18. A porous resin film obtained by the method for producing a porous resin film according to claim 1, wherein the porous resin film is used as an interlayer insulating film or a semiconductor protective film.   A semiconductor device comprising a porous resin film obtained by the method for producing a porous resin film according to claim 1.

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