KR20160135802A - Epoxy resin composition and electrostatic-capacitance-type fingerprint sensor - Google Patents

Abstract

The epoxy resin composition of the present invention comprises a substrate 101, a detection electrode 103 provided on the substrate 101, and a capacitance type fingerprint sensor 100 In the insulating film 105 constituting the insulating film. The epoxy resin composition of the present invention comprises an epoxy resin (A) and an inorganic filler (B).

Description

EPOXY RESIN COMPOSITION AND ELECTROSTATIC-CAPACITANCE-TYPE FINGERPRINT SENSOR [0002]

The present invention relates to an epoxy resin composition and a capacitance type fingerprint sensor.

As for the fingerprint sensor, various techniques are being studied. For example, in Patent Document 1, a semiconductor fingerprint sensor that detects fingerprint information by a capacitive method has been studied.

Patent Document 1 discloses a fingerprint read sensor in which electrodes are arranged in an array with an interlayer film interposed therebetween on a substrate made of silicon or the like and the upper surface thereof is overcoated with an insulating film.

Japanese Patent Application Laid-Open No. 2004-234245

It is required to improve the sensitivity of a capacitive type fingerprint sensor including a substrate, a detecting electrode provided on the substrate, and an insulating film sealing the detecting electrode.

According to the present invention,

A substrate;

A detection electrode provided on the substrate,

An insulating film

The fingerprint sensor according to claim 1,

An epoxy resin (A)

The inorganic filler (B)

Is provided.

According to the present invention,

A substrate;

A detection electrode provided on the substrate,

The sensing electrode is sealed, and the insulating film formed by the cured product of the epoxy resin composition

The fingerprint sensor according to claim 1,

According to the present invention, the sensitivity of the capacitive type fingerprint sensor can be improved.

The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments thereof with reference to the accompanying drawings.
1 is a cross-sectional view schematically showing a capacitive type fingerprint sensor according to the present embodiment.

Hereinafter, embodiments will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and a description thereof will be omitted.

1 is a cross-sectional view schematically showing a capacitance type fingerprint sensor 100 according to the present embodiment.

The capacitance type fingerprint sensor 100 according to the present embodiment includes a substrate 101, a detection electrode 103 provided on the substrate 101, and an insulating film 105 for sealing the detection electrode 103 have. The insulating film 105 is formed by a cured product of the epoxy resin composition. The epoxy resin composition includes an epoxy resin (A) and an inorganic filler (B).

The inventor of the present invention has found that the insulating film for sealing the detection electrode can be constituted by the cured product of the epoxy resin composition containing the epoxy resin (A) and the inorganic filler (B), thereby improving the sensitivity of the capacitance type fingerprint sensor And found the structure of the present embodiment.

According to the present embodiment, the insulating film 105 for sealing the detecting electrode 103 is composed of a cured product of an epoxy resin composition containing an epoxy resin (A) and an inorganic filler (B). Such a cured product has excellent dielectric properties. Thus, the sensitivity of the capacitance type fingerprint sensor 100 can be improved. Here, in this embodiment, the excellent dielectric property means, for example, that the dielectric constant and dielectric tangent are high and the capacitance is large.

Hereinafter, the epoxy resin composition according to the present embodiment will be described in detail.

The epoxy resin composition is used to form an insulating film 105 for sealing the detecting electrode 103 provided on the substrate 101. [ The encapsulation molding using the epoxy resin composition is not particularly limited, but can be performed by, for example, a transfer molding method or a compression molding method. The epoxy resin composition is, for example, a tablet shape or a granule. When the epoxy resin composition is in a tablet shape, the epoxy resin composition can be molded using, for example, a transfer molding method. When the epoxy resin composition is in the form of a powder, the epoxy resin composition can be molded by using, for example, a compression molding method. The epoxy resin composition is referred to as a powder compact in the case of either a powder form or a granular form.

(Epoxy resin (A))

As the epoxy resin (A), monomers, oligomers and polymers having two or more epoxy groups in one molecule can be used, and their molecular weight and molecular structure are not particularly limited.

In the present embodiment, examples of the epoxy resin (A) include biphenyl type epoxy resins; Bisphenol A type epoxy resins, bisphenol F type epoxy resins, and tetramethyl bisphenol F type epoxy resins; Stilbene type epoxy resin; Novolak type epoxy resins such as phenol novolak type epoxy resin and cresol novolak type epoxy resin; Polyfunctional epoxy resins such as triphenol methane type epoxy resin and alkyl modified triphenolmethane type epoxy resin; Phenolic aralkyl type epoxy resins having a phenylene skeleton, phenolic aralkyl type epoxy resins having a biphenylene skeleton, and the like; Dihydroxynaphthalene type epoxy resins, naphthol type epoxy resins such as epoxy resins obtained by glycidyl etherating dimers of dihydroxynaphthalene; Triazine nucleus-containing epoxy resins such as triglycidyl isocyanurate and monoallyl diglycidyl isocyanurate; And dicyclopentadiene-modified phenol-type epoxy resins. These epoxy resins may be used singly or in combination of two or more kinds.

Of these, at least one of a bisphenol-type epoxy resin, a novolac-type epoxy resin, a biphenyl-type epoxy resin, a phenol aralkyl-type epoxy resin, and a triphenolmethane-type epoxy resin is included from the viewpoint of improving the balance between humidity- And more preferably at least one of a biphenyl type epoxy resin and a phenol aralkyl type epoxy resin.

As the epoxy resin (A), those containing at least one member selected from the group consisting of an epoxy resin represented by the following formula (1), an epoxy resin represented by the following formula (2) and an epoxy resin represented by the following formula (3) Is particularly preferable.

[Chemical Formula 1]

(Formula (1) of, Ar ¹ is a phenyl group or, if represents a naphthylene, Ar ¹ is naphthylene group, glycidyl ether group α position, β may be bonded on either side of the location. Ar ² is a phenylene group, biphenyl group or naphthyl group represents any of the groups of the group. R _a and R _b each independently represents a hydrocarbon having a carbon number of 1 ~ 10. g is an integer of 0 to 5, h is an integer from 0-8 N ³ represents a degree of polymerization, and the average value thereof is 1 to 3)

(2)

(In the formula (2), plural R _c present in each independently represent a hydrogen atom or a hydrocarbon group of 1 to 4 carbon atoms, and n ⁵ represents a degree of polymerization and an average value thereof is 0 to 4)

(3)

(Wherein R _d and R _{e which} are plural in the formula (3) each independently represent a hydrogen atom or a hydrocarbon group of 1 to 4 carbon atoms, n ⁶ represents a degree of polymerization and the average value thereof is 0 to 4)

In the present embodiment, the content of the epoxy resin (A) in the epoxy resin composition is preferably 2% by mass or more, more preferably 3% by mass or more based on 100% by mass of the whole epoxy resin composition, And particularly preferably at least 4% by mass. By setting the content of the epoxy resin (A) to the above-mentioned lower limit value or more, sufficient fluidity can be realized at the time of molding, and filling and formability can be improved.

On the other hand, the content of the epoxy resin (A) in the epoxy resin composition is preferably 30% by mass or less, more preferably 20% by mass or less, more preferably 10% by mass or less based on 100% by mass of the entire epoxy resin composition. Or less. By making the content of the epoxy resin (A) equal to or lower than the upper limit value described above, it is possible to improve moisture resistance reliability and resistance to reflow with respect to the capacitance type fingerprint sensor 100 using the cured product of the epoxy resin composition as the insulating film 105 .

(Inorganic filler (B))

The constituent material of the inorganic filler (B) is not particularly limited, and examples thereof include titanium oxide, tantalum pentoxide, niobium pentoxide, barium titanate, silica, alumina, kaolin, talc, clay, mica, A glass fiber, a glass fiber, a silicon carbide, a silicon nitride, an aluminum nitride, a carbon black, a graphite, a titanium dioxide, a calcium carbonate, a calcium sulfate, a barium carbonate, a magnesium carbonate, a magnesium sulfate, a barium sulfate, , Wood, or a phenolic resin molding material, or a ground powder obtained by crushing a cured product of an epoxy resin molding material. Any one or more of these may be used.

Of these, an inorganic filler having a relative dielectric constant (1 MHz) of 5 or more is preferable, and titanium oxide, alumina, tantalum pentoxide, niobium pentoxide, barium titanate or the like is preferable from the viewpoint that the relative dielectric constant of the cured product of the obtained epoxy resin composition can be particularly improved. And more preferably one or two or more selected from alumina, titanium oxide and barium titanate are used, and it is more preferable to use one or two or more selected from among titanium oxide and barium titanate It is more preferable to use two or more species, and from the viewpoint of suppressing oxidation deterioration of the resin, it is particularly preferable to use rutile type titanium oxide.

In the present embodiment, the content of the inorganic filler (B) in the epoxy resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, based on the whole epoxy resin composition when the total amount of the epoxy resin composition is 100% , And particularly preferably 80 mass% or more. By setting the content of the inorganic filler (B) to the lower limit value or more, the dielectric property of the epoxy resin composition can be further improved and the sensitivity of the capacitance type fingerprint sensor 100 can be further improved.

On the other hand, the content of the inorganic filler (B) in the epoxy resin composition is preferably 97% by mass or less, more preferably 95% by mass or less, based on 100% by mass of the whole epoxy resin composition. By setting the content of the inorganic filler (B) to the upper limit value or less, it becomes possible to more effectively improve the fluidity and the filling property at the time of molding the epoxy resin composition.

The average particle diameter D ₅₀ of the inorganic filler (B) is preferably 0.01 μm or more and 50 μm or less, more preferably 0.1 μm or more and 30 μm or less. By setting the average particle diameter D ₅₀ to be equal to or more than the above lower limit value, the flowability of the epoxy resin composition is made to be good, and the moldability can be improved more effectively. Further, by setting the average particle diameter D ₅₀ to be not more than the upper limit value, occurrence of clogging of the gate can be reliably suppressed. In order to improve the sensitivity of the fingerprint sensor, when the thickness D of the insulating film 105 on the substrate 101 (for example, a silicon chip) is as thin as 50 m or less, The average particle diameter D ₅₀ of the inorganic filler (B) is preferably 10 μm or less, and more preferably 5 μm or less. The average particle diameter D ₅₀ was measured by using a commercially available laser type particle size distribution analyzer (for example, Shimadzu Seisakusho Co., Ltd., SALD-7000) to measure the particle size distribution on the volume basis, (D ₅₀ ) can be made an average particle diameter D ₅₀ .

As the titanium oxide, those known to those skilled in the art can be used.

The content of the titanium oxide in the inorganic filler (B) is not particularly limited, but is preferably 1% by mass or more and 100% by mass or less, more preferably 2% by mass or more and 80% By mass, and particularly preferably from 5% by mass to 50% by mass.

By setting the content of titanium oxide to the lower limit value or more, the dielectric property of the epoxy resin composition can be further improved and the sensitivity of the capacitance type fingerprint sensor 100 can be further improved. Further, by setting the content of titanium oxide to be not more than the upper limit value, the flowability of the epoxy resin composition can be made good, and the moldability can be improved more effectively.

The average particle diameter D ₅₀ of the titanium oxide is preferably 0.01 μm or more and 20 μm or less, more preferably 0.1 μm or more and 15 μm or less. By setting the average particle diameter D ₅₀ to be equal to or more than the above lower limit value, the flowability of the epoxy resin composition is made to be good, and the moldability can be improved more effectively. Further, by setting the average particle diameter D ₅₀ to be not more than the upper limit value, occurrence of clogging of the gate can be reliably suppressed. In order to improve the sensitivity of the fingerprint sensor, when the thickness D of the insulating film 105 on the substrate 101 (for example, a silicon chip) is as thin as 50 m or less, The average particle diameter D ₅₀ of the titanium oxide is preferably 10 μm or less, more preferably 5 μm or less.

As the barium titanate, those known to those skilled in the art can be used.

The content of barium titanate in the inorganic filler (B) is not particularly limited, but is preferably 10% by mass or more and 100% by mass or less, more preferably 25% by mass or more and 90% by mass Or less, more preferably 40 mass% or more and 75 mass% or less.

By setting the content of barium titanate to the lower limit value or more, the dielectric property of the epoxy resin composition can be further improved and the sensitivity of the capacitance type fingerprint sensor 100 can be further improved. Further, by setting the content of barium titanate to be not more than the upper limit value, the flowability of the epoxy resin composition is made to be good, and the formability can be improved more effectively.

The average particle diameter D ₅₀ of barium titanate is preferably 0.01 μm or more and 20 μm or less, more preferably 0.1 μm or more and 15 μm or less. By setting the average particle diameter D ₅₀ to be equal to or more than the above lower limit value, the flowability of the epoxy resin composition is made to be good, and the moldability can be improved more effectively. Further, by setting the average particle diameter D ₅₀ to be not more than the upper limit value, occurrence of clogging of the gate can be reliably suppressed. In order to improve the sensitivity of the fingerprint sensor, when the thickness D of the insulating film 105 on the substrate 101 (for example, a silicon chip) is as thin as 50 m or less, The average particle diameter D ₅₀ of barium titanate is preferably 10 μm or less, and more preferably 5 μm or less.

The inorganic filler (B) may be one or more kinds selected from titanium oxide, alumina, tantalum pentoxide, niobium pentoxide and barium titanate from the viewpoint of suppressing the deformation of the fingerprint sensor while improving the sensitivity of the obtained fingerprint sensor The inorganic filler and silica are preferably used in combination, and it is more preferable to use silica particles in combination with at least one inorganic filler selected from alumina, titanium oxide, and barium titanate, and titanium oxide and barium titanate It is particularly preferable to use silica particles in combination with one or more selected inorganic fillers.

In the present embodiment, it is preferable that the inorganic filler (B) contains fine silica having an average particle diameter of 1 탆 or less from the viewpoints of improving the filling property of the epoxy resin composition and from the viewpoint of suppressing deformation of the fingerprint sensor, As shown in FIG.

(Curing agent (C))

The epoxy resin composition may contain, for example, a curing agent (C). The curing agent (C) is not particularly limited as long as it is cured by reacting with the epoxy resin (A), and examples thereof include linear aliphatic diamines having 2 to 20 carbon atoms such as ethylenediamine, trimethylenediamine, tetramethylenediamine and hexamethylenediamine, Diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, and 4,4'-diaminodiphenyl ether. Diaminodiphenylsulfone, 4,4'-diaminodicyclohexane, bis (4-aminophenyl) phenylmethane, 1,5-diaminonaphthalene, metaxylenediamine, para-xylenediamine, 1,1-bis (4-aminophenyl) cyclohexane, and dicyanodiamide; Resol type phenol resins such as aniline-modified resole resin and dimethylether resole resin; Novolak type phenol resins such as phenol novolak resin, cresol novolac resin, tert-butyl phenol novolac resin, nonyl phenol novolac resin, and tris phenol methane type phenol novolac resin; Phenol aralkyl resins such as a phenol skeleton-containing phenol aralkyl resin and a biphenylene skeleton-containing phenol aralkyl resin; A phenol resin having a condensed polycyclic structure such as a naphthalene skeleton or an anthracene skeleton; Polyoxystyrene such as polyparaxylylene and polyparaxylylene; Alicyclic acid anhydrides such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA), anhydrides such as trimellitic anhydride (TMA), pyromellitic acid anhydride (PMDA) and benzophenone tetracarboxylic acid (BTDA) Acid anhydrides including acid anhydrides and the like; Polymercaptan compounds such as polysulfide, thioester, and thioether; Isocyanate compounds such as isocyanate prepolymer and blocked isocyanate; And carboxylic acids-containing polyester resin. These may be used alone or in combination of two or more.

The content of the curing agent (C) in the epoxy resin composition is not particularly limited, but is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1.5% by mass or less, More preferably not less than 20% by mass, further preferably not less than 2% by mass and not more than 15% by mass, particularly preferably not less than 2% by mass and not more than 10% by mass.

(Coupling agent (D))

The epoxy resin composition may contain, for example, a coupling agent (D). Examples of the coupling agent (D) include various silane compounds such as epoxy silane, mercaptosilane, aminosilane, alkylsilane, ureide silane and vinylsilane, titanium compounds, aluminum chelates and aluminum / zirconium compounds A known coupling agent can be used.

Examples of these include vinyl trichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (? -Methoxyethoxy) silane,? -Methacryloxypropyltrimethoxysilane,? - (3,4 -Epoxycyclohexyl) ethyltrimethoxysilane,? -Glycidoxypropyltrimethoxysilane,? -Glycidoxypropyltriethoxysilane,? -Glycidoxypropylmethyldimethoxysilane,? -Methacryloxypropyl Methyldiethoxysilane,? -Methacryloxypropyltriethoxysilane, vinyltriacetoxysilane,? -Mercaptopropyltrimethoxysilane,? -Aminopropyltriethoxysilane,? -Anilinopropyltrimethoxysilane ,? - [(? - hydroxyethyl)] aminopropyltriethoxysilane, N -? - (aminoethyl) -? - aminopropyltrimethoxysilane, N- ? - (aminoethyl) -? - aminopropyltriethoxysilane, N -? - (aminoethyl) -? - amino Aminopropyltrimethoxysilane, N- (trimethoxysilylpropyl) ethylenediamine, N- (dimethoxyethyl) aminopropyltrimethoxysilane, N-phenyl- (N-vinylbenzylaminoethyl) -? - aminopropyltrimethoxysilane,? -Methyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, N- 3-isocyanatopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, hexamethyldisilane, vinyltrimethoxysilane,? -Mercaptopropylmethyldimethoxysilane, Silane coupling agents such as hydrolysates of ethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, isopropyltriisostearoyltitanate, isopropyl tris (dioctylpyrophosphate) tie Thionate, isopropyltri (N-aminoethyl-amino ) Tetrabutyl titanate, tetra octyl bis (ditridecyl phosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, bis Pyrophosphate) oxyacetate titanate, bis (dioctyl pyrophosphate) ethylene titanate, isopropyl trioctanoyl titanate, isopropyldimacrylyl isostearoyltitanate, isopropyltridodecyl (Isopropyltriisopropyltriethoxysilane), benzenesulfonyltitanate, isopropyl diisostearoyldiacrylate, isopropyltri (dioctylphosphate) titanate, isopropyltricumylphenyltitanate, tetraisopropylbis (dioctylphosphite) tie And a titanate-based coupling agent such as a titanate. These may be used singly or in combination of two or more kinds.

The content of the coupling agent (D) in the epoxy resin composition is not particularly limited. For example, when the total amount of the epoxy resin composition is 100 mass%, the content is preferably 0.01 mass% or more and 3 mass% or less, more preferably 0.1 mass% Or more and 2 mass% or less. By setting the content of the coupling agent (D) to the lower limit value or more, the dispersibility of the inorganic filler (B) in the epoxy resin composition can be improved. Further, by setting the content of the coupling agent (D) to the upper limit value or less, the fluidity of the epoxy resin composition is made to be good, and the moldability can be improved.

(Other component (E))

The epoxy resin composition may contain, in addition to the above components, a phosphorus compound such as an organic phosphine, a tetra-substituted phosphonium compound, a phosphobetaine compound, an adduct of a phosphine compound and a quinone compound or an adduct of a phosphonium compound and a silane compound Or an amidine-based compound such as 1,8-diazabicyclo (5.4.0) undecene-7 or imidazole, a tertiary amine such as benzyldimethylamine, or an amidinium salt such as a quaternary onium salt of the above compound , Or a nitrogen atom-containing compound represented by an ammonium salt or the like; Coloring agents such as carbon black; Release agents such as polybutadiene compounds, acrylonitrile butadiene copolymer compounds, natural waxes, synthetic waxes, higher fatty acids or metal salts thereof, paraffins and polyethylene oxide; Low stress agents such as silicone oil and silicone rubber; Ion trapping agents such as hydrotalcite; Flame retardants such as aluminum hydroxide; Antioxidants, and the like.

The relative dielectric constant ( _r ) at 1 MHz of the cured product of the epoxy resin composition is preferably 5 or more, more preferably 7 or more, and particularly preferably 8 or more. By setting the relative permittivity? _R to the lower limit value or more, the dielectric property of the epoxy resin composition can be further improved, and the sensitivity of the capacitance type fingerprint sensor 100 can be further improved.

When the epoxy resin composition is in tablet form, the cured product of the epoxy resin composition is molded by injection molding using, for example, a transfer molding machine under the conditions of a mold temperature of 175 캜, an injection pressure of 9.8 MPa, and a curing time of 300 seconds. . The cured product is, for example, 50 mm in diameter and 3 mm in thickness.

When the epoxy resin composition is in the form of a powder, the cured product of the epoxy resin composition can be obtained, for example, by using a compression molding machine under the conditions of a mold temperature of 175 캜, a molding pressure of 9.8 MPa, and a curing time of 300 seconds. Injection molding. The cured product is, for example, 50 mm in diameter and 3 mm in thickness.

The relative dielectric constant? _R of the cured product can be measured, for example, by Q-Meter 4342A manufactured by YOKOGAWA-HEWLETT PACKARD.

The upper limit of the relative dielectric constant? _R is not particularly limited, but is, for example, 300 or less.

The dielectric loss tangent (tan?) Of the cured product of the epoxy resin composition at 1 MHz is preferably 0.005 or more, more preferably 0.006 or more, and still more preferably 0.007 or more.

By setting the dielectric tangent (tan delta) to the lower limit value or more, the dielectric property of the epoxy resin composition can be further improved and the sensitivity of the capacitance type fingerprint sensor 100 can be further improved.

When the epoxy resin composition is in tablet form, the cured product of the epoxy resin composition is molded by injection molding using, for example, a transfer molding machine under the conditions of a mold temperature of 175 캜, an injection pressure of 9.8 MPa, and a curing time of 300 seconds. . The cured product is, for example, 50 mm in diameter and 3 mm in thickness.

When the epoxy resin composition is in the form of a powder, the cured product of the epoxy resin composition can be obtained, for example, by using a compression molding machine under the conditions of a mold temperature of 175 캜, a molding pressure of 9.8 MPa, and a curing time of 300 seconds. Injection molding. The cured product is, for example, 50 mm in diameter and 3 mm in thickness.

The dielectric tangent (tan?) Of the cured product can be measured by, for example, Q-Meter 4342A manufactured by YOKOGAWA-HEWLETT PACKARD.

The upper limit of the dielectric tangent (tan?) Is not particularly limited, but is, for example, 0.07 or less.

The relative dielectric constant ( _r ) and the dielectric loss tangent (tan delta) can be controlled by appropriately adjusting the kinds and blending ratios of the components constituting the epoxy resin composition. In the present embodiment, particularly suitably selecting the kind of the inorganic filler (B) can be mentioned as a factor for controlling the dielectric constant (? _R ) and the dielectric tangent (tan?). For example, the more the inorganic filler having a large dielectric constant is used, the higher the dielectric constant? _R and the dielectric tangent (tan?) Of the cured product of the epoxy resin composition can be improved.

The flow length (flow length) measured by the spiral flow measurement is preferably 30 cm or more and 200 cm or less, more preferably 40 cm or more and 150 cm or less, in the epoxy resin composition. As a result, the moldability of the epoxy resin composition can be improved. In the present embodiment, the spiral flow measurement of the epoxy resin composition is carried out by using a transfer molding machine, for example, in a mold for spiral flow measurement according to EMMI-1-66, at a mold temperature of 175 占 폚, an injection pressure of 9.8 MPa, 15 seconds and a curing time of 120 to 180 seconds, and measuring the flow field.

In the present embodiment, the glass transition temperature of the cured product of the epoxy resin composition is preferably 100 占 폚 or higher, more preferably 120 占 폚 or higher. Thus, the heat resistance of the fingerprint sensor can be improved more effectively. On the other hand, the upper limit value of the glass transition temperature is not particularly limited, but may be, for example, 250 캜.

In the present embodiment, the coefficient of linear expansion (CTE1) of the cured product of the epoxy resin composition at a glass transition temperature or lower is preferably 3 ppm / DEG C or higher, more preferably 6 ppm / DEG C or higher. The coefficient of linear expansion (CTE1) at a glass transition temperature or lower is preferably 50 ppm / 占 폚 or lower, for example, and more preferably 30 ppm / 占 폚 or lower. By controlling the CTE1 in this way, deformation of the fingerprint sensor due to the difference in linear expansion coefficient between the substrate 101 (for example, a silicon chip) and the insulating film 105 can be suppressed more reliably.

In the present embodiment, it is preferable that the coefficient of linear expansion (CTE2) of the cured product of the epoxy resin composition at a temperature above the glass transition temperature is 10 ppm / DEG C or more. The coefficient of linear expansion (CTE2) at a temperature above the glass transition temperature is preferably, for example, 100 ppm / 占 폚 or lower. By controlling the CTE2 in this way, deformation of the fingerprint sensor due to the difference in linear expansion coefficient between the substrate 101 (for example, a silicon chip) and the insulating film 105 can be more reliably suppressed, especially under a high temperature environment .

The glass transition temperature and the coefficient of linear expansion (CTE1, CTE2) of the cured product of the epoxy resin composition can be measured, for example, as follows.

First, when the epoxy resin composition is in a tablet shape, the cured product of the epoxy resin composition is prepared by, for example, using a transfer molding machine under the conditions of a mold temperature of 175 캜, an injection pressure of 9.8 MPa, and a curing time of 300 seconds. Injection molding. The cured product is, for example, 10 mm long, 4 mm wide and 4 mm thick.

When the epoxy resin composition is in the form of a powder, the cured product of the epoxy resin composition can be obtained, for example, by using a compression molding machine under the conditions of a mold temperature of 175 캜, a molding pressure of 9.8 MPa, and a curing time of 300 seconds. Injection molding. The cured product is, for example, 10 mm long, 4 mm wide and 4 mm thick.

Then, the obtained cured product was post-cured at 175 DEG C for 4 hours, and then measured by a thermomechanical analyzer (TMA100, manufactured by Seiko Denshi Kogyo Co., Ltd.) at a measurement temperature range of 0 DEG C to 320 DEG C and a temperature rise rate of 5 DEG C / The measurement is performed under the following conditions. From these measurement results, the coefficient of linear expansion (CTE1) at a temperature lower than the glass transition temperature, the glass transition temperature, and the coefficient of linear expansion (CTE2) at the temperature exceeding the glass transition temperature are calculated.

The coefficient of linear expansion (CTE1) at the glass transition temperature, the glass transition temperature or lower and the coefficient of linear expansion (CTE2) at a temperature higher than the glass transition temperature are controlled by appropriately adjusting the kinds and mixing ratios of the components constituting the epoxy resin composition It is possible to do. In the present embodiment, the selection of the type of the inorganic filler (B) can be mentioned as a factor for controlling CTE1 and CTE2. For example, by using silica particles having a small linear expansion coefficient as the inorganic filler (B), CTE1 and CTE2 of the cured product of the epoxy resin composition can be lowered.

Hereinafter, the configuration of the capacitance type fingerprint sensor 100 according to the present embodiment will be described in detail.

The capacitance type fingerprint sensor 100 according to the present embodiment is a fingerprint sensor that reads fingerprint information by, for example, a capacitive method for sensing capacitance with a finger. Here, the fingerprint sensor reads the unevenness of the finger placed on the fingerprint sensor. For example, the capacitance type fingerprint sensor 100 is provided with a detection electrode 103 that is finer than the irregularities of the fingerprint. Then, a two-dimensional image showing the irregularities of the fingerprint is created by the electrostatic capacity accumulated between the irregularities of the fingerprint and the detection electrode 103. For example, since the capacitance detected at the convex portion and the concave portion of the fingerprint is different from each other, a two-dimensional image showing the irregularities of the fingerprint can be created from the difference in capacitance. The fingerprint information can be read by the two-dimensional image.

1 is a cross-sectional view schematically showing a capacitance type fingerprint sensor 100 according to the present embodiment.

The capacitance type fingerprint sensor 100 according to the present embodiment includes a substrate 101, a detection electrode 103 provided on the substrate 101, and an insulating film 105 for sealing the detection electrode 103 have.

In the present embodiment, the insulating film 105 is formed by a cured product of an epoxy resin composition. As the epoxy resin composition, for example, the above-mentioned respective components are mixed by known means and melt-kneaded by a kneader such as a roll, a kneader or an extruder, cooled and then pulverized, And those in which the degree of dispersion and the fluidity are appropriately adjusted as needed can be used.

In order to improve the sensitivity of the fingerprint sensor, the thickness D of the insulating film 105 on the substrate 101 (for example, a silicon chip) is, for example, 100 μm or less, more preferably 75 μm or less, Lt; / RTI >

The substrate 101 is, for example, a chip-shaped silicon substrate. The detection electrodes 103 are formed of, for example, an Al film, and are arranged on the substrate 101 in a one-dimensional or two-dimensional array shape with an interlayer film 107 interposed therebetween. The interlayer film 107 is formed of, for example, SiO _{2 or the} like.

The upper surface of the detection electrode 103 is covered with an insulating film 105. The detecting electrode 103 is wire-bonded, for example.

The capacitance type fingerprint sensor 100 according to the present embodiment can be manufactured based on known information. For example, as follows.

First, an interlayer film 107 is formed on a substrate 101, and then a detecting electrode 103 is formed on the interlayer film 107. Subsequently, the detection electrode 103 is encapsulated with an epoxy resin composition. Examples of the molding method include a transfer molding method, a compression molding method, a casting mold, and the like. Subsequently, the epoxy resin composition is thermally cured to form an insulating film 105. Thus, the capacitance type fingerprint sensor 100 according to the present embodiment is obtained.

Next, the effect of the present embodiment will be described.

According to the present embodiment, the insulating film 105 for sealing the detecting electrode 103 is composed of a cured product of an epoxy resin composition containing an epoxy resin (A) and an inorganic filler (B). Since the cured product of the epoxy resin composition has excellent dielectric properties, the sensitivity of the capacitance type fingerprint sensor 100 can be improved.

Example

Next, an embodiment of the present invention will be described.

(Preparation of epoxy resin composition)

With respect to Examples 1 to 9, an epoxy resin composition was prepared as follows. First, each component blended according to Table 1 was mixed at room temperature using a high-speed mixer. Subsequently, the resulting mixture was subjected to roll kneading (high-temperature side roll surface temperature 90 ° C, low-temperature side roll surface temperature 25 ° C), followed by cooling and pulverization by blender to obtain an epoxy resin composition. Details of each component in Table 1 are as follows.

(A) an epoxy resin

Epoxy resin 1: Biphenyl-type epoxy resin (YX-4000K, manufactured by Mitsubishi Kagaku Co., Ltd.)

(B) Inorganic filler

Inorganic filler 1: Alumina (DAB-45SI, D ₅₀ = 17 μm, manufactured by Denki Kagaku Kogyo Co., Ltd.)

Inorganic filler 2: silica (Denki Kagaku Kogyo Co., FB105, D ₅₀ = 10μm)

Inorganic filler 3: Silica (REOLOSIL CP-102, D ₅₀ = 1 μm or less, manufactured by Tokuyama Co., Ltd.)

Inorganic filler 4: Silica (Admah Tex _{Co., SO-25R, D 50 =} 0.5μm)

Inorganic filler 5: titanium oxide (IV) (PF-726, D ₅₀ = 1 탆, rutile type, content of titanium oxide having a particle size of 32 탆 or more and 5%

Inorganic filler 6: Barium titanate (FalSerum BT-UP2, D ₅₀ = 2 탆, content of barium titanate having a particle diameter of 32 탆 or more and 5% by mass or less, manufactured by Nippon Kayaku Kogyo Co.,

Inorganic filler 7: alumina (Micron Co., AX3-15R, the content of the alumina particle size is less than 15μm 5% by mass or less, D ₅₀ = 4μm)

(C) Curing agent

Curing agent 1: Trisphenol methane-type phenol novolac resin (MEH-7500, manufactured by Meiwa Kasei Kasei)

Curing agent 2: trisphenol methane-type phenol novolac resin (HE910-20, manufactured by Air Water)

(D) Coupling agent

Coupling agent 1: N-phenyl- gamma -aminopropyltrimethoxysilane (CF4083, manufactured by Dow Corning Toray Co., Ltd.)

(E) Other components

Curing accelerator 1: Curing accelerator represented by the following formula (4)

[Chemical Formula 4]

[Synthesis method of curing accelerator 1]

37.5 g (0.15 mol) of 4,4'-bisphenol S and 100 ml of methanol were introduced into a separable flask equipped with a stirrer, and stirred and dissolved at room temperature. While further stirring, 4.0 g (0.1 mol) of sodium hydroxide was added to 50 ml of methanol, Was added. Subsequently, a solution prepared by dissolving 41.9 g (0.1 mole) of tetraphenylphosphonium bromide in 150 ml of methanol was added. Stirring was continued for a while, 300 ml of methanol was added, and the solution in the flask was added dropwise to a large amount of water with stirring to obtain a white precipitate. The precipitate was filtered and dried to obtain curing accelerator 1 as a white crystal.

Curing accelerator 2: Curing accelerator represented by the following formula (5)

[Chemical Formula 5]

[Synthesis method of curing accelerator 2]

249.5 g of phenyltrimethoxysilane and 384.0 g of 2,3-dihydroxynaphthalene were added to and dissolved in a flask containing 1800 g of methanol, followed by dropwise addition of 231.5 g of a 28% sodium methoxide-methanol solution under stirring at room temperature. Further, a solution prepared by dissolving 503.0 g of tetraphenylphosphonium bromide prepared in advance in 600 g of methanol was added dropwise with stirring at room temperature to precipitate crystals. The precipitated crystals were filtered, washed with water and vacuum-dried to obtain Curing Accelerator 2 of whitish color crystal.

Low stress 1: acrylonitrile butadiene rubber (UBE, Ltd., carboxyl-terminated butadiene acrylic rubber, CTBN1008SP)

Low stress: Silicone oil

Colorant: Carbon black

Release agent: carnauba wax

Ion trap agent: hydrotalcite

(Measurement of relative dielectric constant and dielectric tangent)

The relative dielectric constant and dielectric loss tangent of the epoxy resin composition were measured as follows in Examples 1 to 9. Using the low pressure transfer molding machine ("KTS-30" manufactured by Kotakiseki K.K.), the above epoxy resin composition was injection-molded into a mold under the conditions of a mold temperature of 175 캜, an injection pressure of 9.8 MPa, and a curing time of 300 seconds To obtain a cured product of the epoxy resin composition. The cured product had a diameter of 50 mm and a thickness of 3 mm.

Next, relative dielectric constant and dielectric loss tangent at 1 MHz and room temperature (25 DEG C) were measured by Q-Meter 4342A manufactured by YOKOGAWA-HEWLETT PACKARD for the obtained cured product. The results are shown in Table 1.

(Measurement of spiral flow)

With respect to Examples 1 to 9, the spiral flow of the epoxy resin composition was measured as follows. Mold temperature of 175 占 폚, injection pressure of 9.8 MPa, injection time of 15 seconds (injection time) was measured by using a low pressure transfer molding machine ("KTS-15" , And a curing time of 180 seconds, and the flow field was measured. The unit in Table 1 is cm. The results are shown in Table 1.

(Glass transition temperature, linear expansion coefficient)

For each of the examples, the glass transition temperature (Tg) and the coefficient of linear expansion (CTE1, CTE2) of the cured product of the epoxy resin composition were measured as follows. Using the low pressure transfer molding machine ("KTS-30" manufactured by Kotakiseki K.K.), the above epoxy resin composition was injection-molded into a mold under the conditions of a mold temperature of 175 캜, an injection pressure of 9.8 MPa, and a curing time of 300 seconds To obtain a cured product of the epoxy resin composition. The cured product had a length of 10 mm, a width of 4 mm and a thickness of 4 mm.

Subsequently, the obtained cured product was post-cured at 175 DEG C for 4 hours, and then measured by a thermomechanical analyzer (TMA100, manufactured by Seiko Denshi Kogyo Co., Ltd.) at a measurement temperature range of 0 DEG C to 320 DEG C and a temperature rise rate of 5 DEG C / Under the following conditions. From the measurement results, the glass transition temperature (Tg), the coefficient of linear expansion (CTE1) at a temperature lower than the glass transition temperature and the coefficient of linear expansion (CTE2) at a temperature above the glass transition temperature were calculated. The results are shown in Table 1.

(Sensitivity Measurement of Capacitive Fingerprint Sensor)

For each of Examples 1 to 9, the capacitance type fingerprint sensor shown in Fig. 1 was produced by using the obtained epoxy resin composition. Subsequently, a two-dimensional image showing the irregularities of the fingerprint was created using the obtained capacitive type fingerprint sensor.

[Table 1]

All of the capacitive type fingerprint sensors obtained in Examples 1 to 9 were clearly displayed with two-dimensional images of fingerprints and showed good sensitivity. Of these, Examples 2 to 9 having particularly excellent dielectric properties exhibited excellent sensitivity because a two-dimensional image of a clearer fingerprint was obtained as compared with Example 1. In addition, Examples 1 to 3, 6 to 7 and 9 showed excellent results in the moldability test.

In the capacitive type fingerprint sensor obtained in Examples 1 to 9, all the deformation was suppressed. The CTE1 of the cured product of the epoxy resin composition obtained in Examples 1 to 9 was all within the range of 3 ppm / DEG C to 50 ppm / DEG C or less. The CTE2 of the cured product of the epoxy resin composition obtained in Examples 1 to 9 was all in the range of 10 ppm / 占 폚 to 100 ppm / 占 폚.

Since the thinness of the thickness D of the insulating film 105 leads to the sensitivity of the fingerprint sensor, the use of the inorganic filler (B) cut with the coarse particles suppresses unfilling or the like during molding It is preferable. The epoxy resin compositions of Examples 7 to 9 were excellent in moldability as compared with the epoxy resin compositions of Examples 1 to 6 because the fingerprint sensor can be formed without filling even when the thickness D of the insulating film 105 is 50 m . In the epoxy resin compositions of Examples 7 to 9, even if the thickness (D) of the insulating film 105 was 50 m, deformation of the fingerprint sensor did not occur. In other words, the epoxy resin compositions of Examples 7 to 9 exhibited excellent moldability while exhibiting good sensitivity, clearly showing the two-dimensional image of the fingerprint.

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2014-062446, filed March 25, 2014, the entire disclosure of which is incorporated herein by reference.

Claims (12)

A substrate;
A detection electrode provided on the substrate,
An insulating film for sealing the detection electrode
The fingerprint sensor according to claim 1,
An epoxy resin (A)
The inorganic filler (B)
≪ / RTI > The method according to claim 1,
Wherein the relative dielectric constant ( _r ) at 1 MHz of the cured product of the epoxy resin composition is 5 or more. The method of claim 2,
Wherein the relative dielectric constant ( _r ) at 1 MHz of the cured product of the epoxy resin composition is 8 or more. The method according to any one of claims 1 to 3,
Wherein the cured product of the epoxy resin composition has a dielectric loss tangent (tan?) Of 0.005 or more at 1 MHz. The method according to any one of claims 1 to 4,
Wherein the inorganic filler (B) comprises at least one selected from alumina, titanium oxide, and barium titanate. The method of claim 5,
Wherein the inorganic filler (B) comprises the titanium oxide,
Wherein the titanium oxide is a rutile type. The method according to claim 5 or 6,
Wherein the inorganic filler (B) further comprises silica particles. The method according to any one of claims 1 to 7,
Wherein the flow field measured by spiral flow measurement at a mold temperature of 175 캜, an injection pressure of 9.8 MPa, and an injection time of 15 seconds is not less than 30 cm and not more than 200 cm. The method according to any one of claims 1 to 8,
Wherein the cured product of the epoxy resin composition has a glass transition temperature of 100 占 폚 or more. The method according to any one of claims 1 to 9,
Wherein the coefficient of linear expansion (CTE1) of the cured product of the epoxy resin composition at a glass transition temperature or less is 3 ppm / DEG C or more and 50 ppm / DEG C or less. The method according to any one of claims 1 to 10,
Wherein the coefficient of linear expansion (CTE2) of the cured product of the epoxy resin composition at a temperature above the glass transition temperature is 10 ppm / DEG C or more and 100 ppm / DEG C or less. A substrate;
A detection electrode provided on the substrate,
The sensing electrode is sealed and the insulating film formed by the cured product of the epoxy resin composition according to any one of claims 1 to 11
And a fingerprint sensor.

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