CN116406331A

CN116406331A - Photosensitive laminated resin structure, dry film, cured product, and electronic component

Info

Publication number: CN116406331A
Application number: CN202180067607.XA
Authority: CN
Inventors: 冈本大地; 宫部英和; 周映暶
Original assignee: Taiyo Holdings Co Ltd
Current assignee: Taiyo Holdings Co Ltd
Priority date: 2020-10-08
Filing date: 2021-10-07
Publication date: 2023-07-07
Also published as: KR20230084182A; WO2022075432A1

Abstract

Providing: a photosensitive laminated resin structure which maintains highly the characteristic function of a highly filled filler and has excellent resolution. The photosensitive laminated resin structure is characterized by comprising: a filler-filled layer (A) and a protective layer (B), wherein the filler-filled layer (A) contains substantially no photopolymerization initiator, the filler content is 10 to 80 mass% of the total components except the organic solvent, and the filler content of the protective layer (B) is 0 to 25 mass% relative to the filler content of the filler-filled layer (A).

Description

Photosensitive laminated resin structure, dry film, cured product, and electronic component

Technical Field

The present invention relates to: a photosensitive laminated resin structure having excellent resolution and useful for a resin insulating layer of a package substrate, a protective film of a printed circuit board on which a light emitting element such as a Light Emitting Diode (LED) is mounted, a resin insulating layer, a dry film comprising the photosensitive laminated resin structure, a cured product of the photosensitive laminated resin structure, and electronic components such as a package substrate and a printed circuit board having a resin insulating layer and a protective layer formed from the cured product.

Background

In recent years, with miniaturization and higher performance of electronic devices, there has been a demand for formation of fine patterns, further reduction in thermal expansion coefficient, and the like for insulating materials used for circuit boards.

In contrast, conventionally, as means for achieving low thermal expansion of such an insulating material, a method of highly filling a filler component such as silica in a composition has been generally known. Among them, spherical silica has been widely used for improving the properties of photosensitive resin compositions such as solder resists because of its excellent filling property and low Coefficient of Thermal Expansion (CTE) (see patent document 1).

In recent years, in the fields of printed circuit boards, backlight lamps for displays such as mobile terminals, personal computers, televisions, and light sources for lighting devices, designs for directly mounting LEDs that emit light with low power have been increasing (see patent literature 2).

For example, in the field of displays, development of Mini-LED displays and micro-LED displays in which red, blue, and green light emitting elements are arranged has been actively performed, and a protective film used in these applications is also required to have a fine pattern (resolution) according to the size of the light emitting element.

In addition, a white protective film excellent in light reflectance is desired to make it possible to effectively use light emission of an LED, in addition to characteristics such as solvent resistance, surface hardness, soldering heat resistance, electrical insulation and the like which are generally required, for a solder resist layer or the like formed as a protective film cover of a printed circuit board on which such an LED is mounted.

Therefore, with the above protective film, in order to improve the reflectance of light, the protective film generally contains a large amount of a filler such as titanium oxide.

In recent years, the higher functionality of semiconductor devices and the higher density of electronic component mounting on printed circuit boards have been advanced. In addition, in a package in which these semiconductor elements and electronic components are integrated at high density, defects due to heat release are a major problem, and excellent heat dissipation properties are required for a circuit board on which the semiconductor elements and electronic components are mounted. For example, patent document 3 discloses a metal base substrate in which a circuit pattern is formed using a metal plate of copper, aluminum, or the like, and an electrical insulating layer such as a prepreg or a thermosetting resin composition is interposed between one or both surfaces of the metal plate.

However, in the above-mentioned metal base substrate, since the thermal conductivity of the electric insulating layer is poor, if the insulating layer is thinned, excellent heat dissipation is not obtained, whereas if the insulating layer is thinned, there is a problem that the insulating withstand voltage in the thickness direction is insufficient.

Accordingly, recently, there has been a demand for improving heat dissipation of a solder resist layer as a protective film of a printed circuit board, and introduction of an inorganic filler such as alumina having high thermal conductivity has been studied (patent document 4).

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2014-81611

Patent document 2: japanese patent laid-open No. 2007-249148

Patent document 3: japanese patent laid-open No. 6-224561 (claims)

Patent document 4: japanese patent laid-open No. 2007-254688 (claims)

Disclosure of Invention

Problems to be solved by the invention

However, in a photosensitive resin composition highly filled with such a filler component, when a coating film formed from the resin composition is subjected to pattern exposure, the irradiated light is reflected and scattered at the interface between the filler component and the resin component or the like, and a phenomenon (so-called halation) occurs in which the photocuring proceeds to a light-shielding region (unexposed region), and therefore there is a problem in that the resolution is deteriorated.

In addition, in the case where the coating film has a high film thickness, the attenuation of the irradiation light in the depth of the coating film is large, and the photocurability in the depth of the coating film cannot be sufficiently obtained, so that there are problems that the developed pattern has an undercut shape, adhesion to the base substrate is lowered, and peeling occurs in the gold plating treatment or the like. Further, in a cured coating film formed from a photosensitive resin composition highly filled with such a filler component, for example, although thermal expansion is reduced, toughness as mechanical characteristics is lowered (embrittlement is caused), and therefore, sufficient crack resistance may not be obtained in a cold and hot cycle test.

In addition, in the manufacturing process of the substrate for mounting an LED and the mounting process of the LED element, which are provided with the white protective film, there are cases where the substrate before mounting the LED is stacked, stored and transported, and the substrate is stored in a rack made of metal or the like and is treated, and therefore, the white protective films on the substrate surface are in contact with each other, the white protective film on the substrate surface is in contact with the rack made of metal or the like, and there is a problem that scratches, cut metal powder or the like adhere to the surface of the protective film and are discolored (so-called scratches). Such problems cause not only deterioration of the external appearance of the LED mounting substrate but also reduction of the reflectance of light. In addition, in the case of forming a pattern by photolithography in a protective film using a filler such as titanium oxide for the purpose of improving the reflectance of light, diffuse reflection occurs in the layer light (UV) of the protective film in proportion to the reflectance and content of light of these fillers, and as a result, the resolution is deteriorated. That is, the reflectance of light of the protective film is in a trade-off relationship with the resolution.

In addition, when a protective film such as a solder resist layer formed on the surface layer of a circuit board is made of an inorganic filler having heat dissipation properties such as alumina, the problem of the scratches is also caused when the board is stacked in a board manufacturing process, stored, transported, and stored in a rack made of metal or the like for processing. In addition, even in the case of forming a pattern by photolithography, in the case of a protective film highly filled with a heat-dissipating filler such as alumina for the purpose of improving heat dissipation, resolution is deteriorated in proportion to the content of the filler. That is, the heat dissipation property of the protective film is also in a trade-off relationship with the resolution.

Accordingly, a primary object of the present invention is to provide: a photosensitive laminated resin structure which has excellent resolution while maintaining highly characteristic functions specific to a highly filled filler, a dry film having the photosensitive laminated resin structure, a cured product of the photosensitive laminated resin structure, and an electronic component having the cured product.

In addition, a first further object of the present invention is to provide: a photosensitive laminated resin structure having a low thermal expansion coefficient and excellent in adhesion, plating resistance, crack resistance and resolution, a dry film comprising the photosensitive laminated resin structure, a cured product of the photosensitive laminated resin structure, and an electronic component comprising the cured product.

A second further object of the present invention is to provide: a photosensitive laminated resin structure which is less likely to cause scratches and has a high reflectance and which can provide a high resolution, a dry film comprising the photosensitive laminated resin structure, a cured product of the photosensitive laminated resin structure, and an electronic component comprising the cured product.

A third further object of the present invention is to provide: a photosensitive laminated resin structure which is less likely to cause scratches and has high heat dissipation properties and which can provide high resolution, a dry film comprising the photosensitive laminated resin structure, a cured product of the photosensitive laminated resin structure, and an electronic component comprising the cured product.

Solution for solving the problem

The present inventors have conducted intensive studies to solve the above problems, and as a result, found that: the present invention has been completed in view of the above problems, and can be achieved by solving the above problems by a laminated resin structure in which a non-photosensitive resin layer containing a filler component at a specific content and a photosensitive resin layer containing a filler component at a smaller content than the non-photosensitive resin layer are laminated.

Specifically, the photosensitive laminated resin structure of the present invention is characterized in that,

the device comprises: a filler-filled layer (A) and a protective layer (B),

the filler-filled layer (A) contains substantially no photopolymerization initiator, and the filler content is 10 to 80 mass% of all components except the organic solvent,

the filler content of the protective layer (B) is 0 to 25% by mass relative to the filler content of the filler-filled layer (A).

In the photosensitive laminated resin structure of the present invention, the filler-filled layer (a) preferably has a layer thickness greater than that of the protective layer (B).

In the photosensitive laminated resin structure of the present invention, the filler is preferably silica.

In the photosensitive laminated resin structure of the present invention, the filler is preferably titanium oxide,

the content of the titanium oxide in the protective layer (B) is 0 to 20 mass% relative to the content of the titanium oxide in the filler-filled layer (a).

The photosensitive laminated resin structure of the present invention is preferably one in which the filler has a thermal conductivity of more than 10W/mK,

the heat-dissipating filler content of the filler-filled layer (A) is 50 to 80 mass% or more of all components except the organic solvent,

the content of the heat-dissipating filler in the protective layer (B) is 0 to 20 mass% relative to the content of the heat-dissipating filler in the filler-filled layer (a).

The dry film of the present invention is characterized in that at least one surface of the photosensitive laminated resin structure is supported or protected by a film.

The cured product of the present invention is characterized by comprising the photosensitive laminated resin structure or the photosensitive laminated resin structure comprising the dry film.

The electronic component of the present invention is characterized by having the aforementioned curing.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there may be provided: a photosensitive laminated resin structure which has excellent resolution while maintaining highly characteristic functions specific to a highly filled filler, a dry film having the photosensitive laminated resin structure, a cured product of the photosensitive laminated resin structure, and an electronic component having the cured product.

In addition, according to the present invention (including those having a low thermal expansion function as a filler), it is possible to provide: a photosensitive laminated resin structure having a low thermal expansion coefficient and excellent in adhesion, plating resistance, crack resistance and resolution, a dry film comprising the photosensitive laminated resin structure, a cured product of the photosensitive laminated resin structure, and an electronic component comprising the cured product.

In addition, according to the present invention (including a white colorant or the like having a light reflecting function as a filler), there can be provided: a photosensitive laminated resin structure which is less likely to cause scratches and has high reflectance and which enables high resolution patterning, a dry film comprising the photosensitive laminated resin structure, a cured product of the photosensitive laminated resin structure, and an electronic component comprising the cured product.

In addition, according to the present invention (including those having a heat dissipation function as a filler), it is possible to provide: a photosensitive laminated resin structure which is less likely to cause scratches and has high heat dissipation properties and which enables high resolution patterning, a dry film comprising the photosensitive laminated resin structure, a cured product of the photosensitive laminated resin structure, and an electronic component comprising the cured product.

Drawings

Fig. 1 is a diagram schematically showing an example of a dry film according to the present invention.

FIG. 2 schematically shows a photosensitive laminated resin using the present invention a process diagram of an example of a method for manufacturing a printed circuit board of a structure.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

The photosensitive laminated resin structure of the present invention is characterized by comprising: a filler-filled layer (A) and a protective layer (B), wherein the filler-filled layer (A) contains substantially no photopolymerization initiator, the filler content is 10 to 80 mass% of the total components except the organic solvent, and the filler content of the protective layer (B) is 0 to 25 mass% relative to the filler content of the filler-filled layer (A).

In the first further object, it is preferable that the filler is silica.

In the second further object, the photosensitive laminated resin structure of the present invention comprises: a filler-filled layer (A) and a protective layer (B), wherein the filler-filled layer (A) contains substantially no photopolymerization initiator, contains titanium oxide as a colorant, and has a titanium oxide content of 10 to 80 mass% in all components except an organic solvent, and the protective layer (B) has a titanium oxide content of 0 to 20 mass% relative to the filler-filled layer (A). In this case, the "filler-filled layer (a)" in the present invention is also referred to as "colored layer (a)".

In the third aspect, the photosensitive laminated resin structure of the present invention comprises: a filler-filled layer (A) and a protective layer (B), wherein the filler-filled layer (A) contains substantially no photopolymerization initiator, contains a heat-dissipating filler having a thermal conductivity of more than 10W/mK, and the content of the heat-dissipating filler is 50 to 80% by mass of all components except the organic solvent, the content of the heat-dissipating filler in the protective layer (B) is 0 to 20 mass% relative to the content of the heat-dissipating filler in the filler-filled layer (a). In this case, the "filler-filled layer (a)" in the present invention is also referred to as "heat dissipation layer (a)".

In the present invention, it is important to form the photosensitive laminated resin structure, that the protective layer (B) having a filler content of not more than a certain ratio (including 0) to the filler content of the filler-filled layer (a) is provided on the filler-filled layer (a), and that the filler-filled layer (a) contains substantially no photopolymerization initiator, whereby the resolution is improved. Further, the first further object is to obtain a cured product having a low thermal expansion coefficient and excellent adhesion, the second further object is to obtain a cured product having a high reflectance and less prone to scratches, and the third further object is to obtain a cured product having a high heat dissipation property and less prone to scratches.

Further, from the viewpoint of further excellent resolution, high reflectance and discoloration resistance after reflow soldering as a second further object, and from the viewpoint of high heat dissipation as a third further object, it is preferable that the filler-filled layer (a) has a layer thickness larger than that of the protective layer (B). For example, the layer thickness of the filler-filled layer (a) is preferably 1.0 times, more preferably 1.5 times or more, and still more preferably 2.0 times or more the layer thickness of the protective layer (B).

The thickness of the filler-filled layer (a) is not limited to this, but is also 3 to 60 μm for the second further object to exhibit sufficient colorability in order to cover the space between the circuits formed on the base substrate without any gap. The layer thickness of the filler-filled layer (A) may be, for example, 10 to 60. Mu.m.

The thickness of the protective layer (B) is, for example, 0.5 to 20 μm in thickness from the viewpoints of solubility resistance to a developer in an exposed portion and plating resistance and crack resistance for the first and further purposes, but is not limited thereto.

In the photosensitive laminated resin structure of the present invention, the filler-filled layer (a) is preferably white in a second further object, and more preferably white when the laminated resin structure is recognized from the side view of the protective layer (B).

In the photosensitive laminated resin structure of the present invention, the filler-filled layer (a) preferably contains an alkali-soluble resin and a thermally reactive compound. The protective layer (B) preferably contains an alkali-soluble resin, a photopolymerization initiator, and a thermally reactive compound. That is, the filler-filled layer (a) and the protective layer (B) are preferably soluble in an aqueous alkali solution at the unexposed portions thereof.

In the photosensitive laminated resin structure of the present invention, the filler-filled layer (a) contains substantially no photopolymerization initiator from the viewpoint of suppressing the occurrence of the halation and improving the resolution. If the filler-filled layer (a) is laminated on the substrate surface side, the protective layer (B) on the outer layer side can be patterned by exposure and development even if the photopolymerization initiator is not contained, and the protective layer (B) and the filler-filled layer (a) can be patterned simultaneously by development.

In the present invention, the substantial absence of a photopolymerization initiator means that: the filler-filled layer (a) has no photopolymerization in the individual layers.

The protective layer (B) preferably contains a compound having a function of generating an alkaline substance by light irradiation as a photopolymerization initiator. In addition, from the viewpoint of resolution, the protective layer (B) preferably contains substantially no low molecular weight compound having an unsaturated double bond capable of undergoing radical polymerization having a molecular weight of 1000 or less.

The filler-filled layer (a) and the protective layer (B) are described in further detail below.

[ Filler layer (A) ]

The filler-filled layer (a) contains a filler at a specific content, and is preferably formed of an alkali-soluble thermosetting resin composition substantially free of a photopolymerization initiator, and more preferably formed of an alkali-soluble thermosetting resin composition further containing an alkali-soluble resin and a thermally reactive compound.

(Filler)

The filler is preferably an inorganic filler. The inorganic filler may be any known inorganic filler used in a general resin composition. Specifically, examples thereof include non-metal fillers such as silica, barium sulfate, calcium carbonate, silicon nitride, aluminum nitride, boron nitride, aluminum oxide (aluminum), magnesium oxide (Magnesia), beryllium oxide (beryllium oxide), aluminum hydroxide, magnesium hydroxide, titanium oxide, mica, talc, organobentonite, diamond, and metal fillers such as copper, gold, silver, palladium, and silicone. They may be used alone or in combination of 2 or more.

In the first further object, among the inorganic fillers, silica is more preferable because it has a low thermal expansion coefficient and is stable to acids, bases, and the like. In the case of combining 2 or more kinds, the combination is not particularly limited, and more preferable combinations of silica and other inorganic fillers are preferable, and examples thereof include combinations of silica and barium sulfate.

As the silica, spherical silica is preferable. Examples of the spherical silica include those having a sphericity of 0.8 or more as measured below, but the spherical silica is not limited to those having a spherical shape.

The sphericity was determined as follows: photographs were taken with SEM, and the area and circumference of the particles observed were taken as (sphericity) = { 4pi× (area)/(circumference) ² And (3) calculating. Specifically, an average value measured for 100 particles by an image processing apparatus was used.

Examples of commercially available silica include spherical silica such as Admafine SO-C2, SO-E2, admanno series, SFP-20-M, SFP-30M, UFP-30, nippon Shokubai Co., ltd., seahostar series, sakai Chemical Industry Co., ltd., sciqas series, NORITAKE CO., LIMITED, and SG-SO100, which are manufactured by Admatechs.

In the first further object, the average particle diameter of the inorganic filler is preferably 0.5 μm or less. If it is 0.5 μm or less, the decrease in resolution can be suppressed. In this specification, the average particle diameter of the filler is not only the particle diameter of the primary particles but also the average particle diameter (D50) including the particle diameter of the secondary particles (aggregates), and is a value of D50 measured by a laser diffraction method. As a measurement device based on the laser diffraction method, microtrac MT3300EXII manufactured by Microtrac BEL corporation may be mentioned.

In the second further object, the inorganic filler may be any one having a light reflecting function, such as a white colorant, and the filler-filled layer (a) is preferably a white inorganic filler, more preferably titanium oxide. The titanium oxide is not particularly limited, and may be rutile titanium oxide or anatase titanium oxide, but rutile titanium is preferably used for colorability, hiding power and stability. Anatase titanium oxide, which is similar to rutile titanium oxide, has a higher whiteness than rutile titanium oxide, and is often used as a white pigment, but since anatase titanium oxide has photocatalytic activity, particularly, discoloration of the resin may occur by light emitted from an LED. In contrast, rutile titanium oxide has slightly lower whiteness than anatase, but is substantially not photoactive, and therefore deterioration (yellowing) of the resin due to photoactive light derived from titanium oxide is significantly suppressed and is also stable to heat. The titanium oxide may be used alone or in combination of 2 or more. The average particle diameter of the titanium oxide is not particularly limited, but is preferably 0.3 μm to 10.0. Mu.m, more preferably 0.5 μm to 5.0. Mu.m. In addition, the filler-filled layer (A) may be used in combination with a bluing agent as a colorant.

As the commercially available rutile type titanium oxide, for example, TIPAQUE R-820, TIPAQUE R-830, TIPAQUE R-930, TIPAQUE R-550, TIPAQUE R-580, TIPAQUE R-630, TIPAQUE R-680, TIPAQUE R-670, TIPAQUE R-680, TIPAQUE R-780, TIPAQUE R-820, TIPAQUE R-850, TIPAQUE CR-50, TIPAQUE CR-57, TIPAQUE CR-Super70, TIPAQUE CR-80, TIPAQUE CR-90, TIPAQUE CR-93, TIPAQUE CR-95, TIPAQUE CR-97, TIPAQUE CR-60, TIPAQUE CR-63, TIPAQUE CR-67, TIPAQUE CR-58, TIPAQUE CR-85, TIPAQUE CR-63, TIPAQUE CR-67, TIPAQUE CR-95, TIPAQUE CR-97, TIPAQUE CR-60, TIPAQUE-VI, TIPAQUE CR-VI, TIPAQU-VI, TIPAK-VI, TIPAQU-VI, TIPAK-VI, and TIPAK-VI, TIPAK-K, and TIPAK-K, and TIR-K, and TIPAQUE UT771 (manufactured by Shimadzu corporation), ti-Pure R-100, ti-Pure R-101, ti-Pure R-102, ti-Pure R-103, ti-Pure R-104, ti-Pure R-105, ti-Pure R-108, ti-Pure R-900, ti-Pure R-902, ti-Pure R-960, ti-Pure R-706, ti-Pure R-931 (manufactured by DuPont corporation), R-25, R-21, R-32, R-7E, R-5N, R-61-N, R-62N, R-42, R-45M, R-44, R-49, GTR-300, D-918, TCR-29, TCR-52, FTR-700 (Sakai Chemical Industry Co., ltd. Made) a, TR-600, TR-700, TR-750, TR-840 (FUJI TITANIUM INDUSTRY CO., LTD.; manufactured by LTD.), KR270, KR310, KR380 (Titan Kogyo, manufactured by Ltd.), etc

Further, as anatase titanium oxide, a known one can be used. As commercially available anatase TITANIUM oxide, TITON A-110, TITON TCA-123E, TITON A-190, TITON A-197, TITON SA-1L (Sakai Chemical Industry Co., ltd.), TA-100, TA-200, TA-300, TA-400, TA-500, TP-2 (FUJI TITANIUM INDUSTRYCO., LTD.), TITANIX JA-1, TITANIX JA-3, TITANIX JA-4, TITANIXJA-5, TITANIX JA-C (manufactured by TAYCA Co., ltd.), KA-10, KA-15, KA-20, KA-30, KA-35, KA-90 (manufactured by Titan Kogyo, ltd.), TIPAQUE A-100, TIPAQUE A-220, PAQUE-10 (manufactured by TIQUE Co., ltd.) and the like can be used.

In the third further object, the inorganic filler may be any filler having heat dissipation properties, and more preferably a heat dissipation filler having a thermal conductivity of more than 10W/m·k. Examples of the heat-dissipating filler having a thermal conductivity higher than 10W/mK include alumina (Al ₂ O ₃ ) And fillers formed of diamond, beryllium oxide (BeO), aluminum nitride (AlN), boron nitride, silicon nitride, magnesium oxide, and the like. The heat-dissipating filler may be used alone or in combination of 2 or more. Among the foregoing heat-dissipating fillers, alumina is also chemically stable, and is excellent in cost and insulation. In particular, by using spherical alumina, an increase in viscosity during high filling can be suppressed. Examples of the spherical alumina include those having a sphericity of 0.8 or more as measured above, but the spherical alumina is not limited to the sphere.

In a third further object, the average particle diameter of the heat-dissipating filler is not particularly limited, but is preferably 0.01 μm to 30 μm, more preferably 0.01 μm to 20 μm. If the average particle diameter is 0.01 μm or more, the viscosity of the composition does not become too high, and the dispersion becomes easy, and the coating of the object to be coated becomes easy. On the other hand, if the average particle diameter is 30 μm or less, the heat-dissipating filler is less likely to protrude even when the coating film is thin, and the sedimentation rate is not excessively high, so that the storage stability is good. Further, the addition of the particles having 2 or more average particle diameters having the particle size distribution of the most densely packed particles is preferable from the viewpoint of storage stability and thermal conductivity, since the particles can be further filled with the particles.

The inorganic filler may be surface-treated. The surface treatment method of the inorganic filler is not particularly limited, and the surface of the inorganic filler may be treated with a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group, or the like, in view of obtaining a cured product having lower thermal expansion by a known conventional method.

As the coupling agent, silane-based, titanate-based, aluminate-based, aluminum zirconate-based, and the like coupling agents can be used. Among them, a silane coupling agent is preferable. Examples of the silane-based coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, N- (2-aminomethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-anilinopropyl trimethoxysilane, 3-glycidoxypropyl methyldimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyl trimethoxysilane, and 3-mercaptopropyl trimethoxysilane, which may be used alone or in combination. These silane coupling agents are preferably immobilized on the surface of the preliminary inorganic filler by adsorption or reaction, and more preferably dispersed (slurried) in an organic solvent and compounded in advance from the viewpoint of further improving dispersibility.

The filler content in the filler-filled layer (A) is 10 to 80 mass% of the total components except the organic solvent.

In the first further object, the silica content in the filler-filled layer (a) is preferably 30 to 70 mass% in all components except the organic solvent. If the amount is within this range, low thermal expansion can be maintained, and deterioration of halation and toughness can be reduced. In the second further object, the content of titanium oxide in the filler-filled layer (a) is preferably 15 to 80 mass%, more preferably 20 to 70 mass% of the total components excluding the organic solvent. In a third further object, the content of the heat-dissipating filler in the filler-filled layer (a) is 50 to 80 mass% in all components except the organic solvent.

(alkali-soluble resin)

The alkali-soluble resin may be a resin containing 1 or more functional groups selected from the group consisting of phenolic hydroxyl groups and carboxyl groups and developable in an aqueous alkali solution. The compound having a phenolic hydroxyl group, the compound having a carboxyl group, and the resin having a phenolic hydroxyl group and a carboxyl group are preferably exemplified. The alkali-soluble resin may have an ethylenically unsaturated double bond. For example, a carboxyl group-containing resin conventionally used as a solder resist composition can be mentioned. The carboxyl group-containing resin may be a carboxyl group-containing photosensitive resin. The alkali-soluble resin may be used alone or in combination of 2 or more.

Specific examples of the alkali-soluble resin include the compounds (both oligomers and polymers) listed below.

(1) Carboxyl group-containing resins obtained by copolymerizing unsaturated carboxylic acids such as (meth) acrylic acid, and unsaturated group-containing compounds such as styrene, α -methylstyrene, lower alkyl (meth) acrylate, and isobutylene.

(2) The carboxyl group-containing polyurethane resin is obtained by polyaddition reaction of aliphatic diisocyanate, branched aliphatic diisocyanate, alicyclic diisocyanate, aromatic diisocyanate and other diisocyanate, and a carboxyl group-containing diol compound such as dimethylolpropionic acid and dimethylolbutyric acid, and a diol compound such as a polycarbonate polyol, polyether polyol, polyester polyol, polyolefin polyol, acrylic polyol, bisphenol A alkylene oxide adduct glycol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

(3) Polyurethane resins are obtained by polyaddition reaction of a diisocyanate compound such as aliphatic diisocyanate, branched aliphatic diisocyanate, alicyclic diisocyanate, or aromatic diisocyanate, and a diol compound such as a polycarbonate polyol, polyether polyol, polyester polyol, polyolefin polyol, acrylic polyol, bisphenol a alkylene oxide adduct diol, or a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group, and a carboxyl group-containing polyurethane resin obtained by reacting the terminal of the polyurethane resin with an acid anhydride.

(4) A carboxyl group-containing polyurethane resin obtained by polyaddition reaction of a diisocyanate, a (meth) acrylate or a partial anhydride modified product thereof with a 2-functional epoxy resin such as a bisphenol A epoxy resin, a hydrogenated bisphenol A epoxy resin, a bisphenol F epoxy resin, a bisphenol S epoxy resin, a bisxylenol epoxy resin, a bisphenol epoxy resin, a carboxyl group-containing diol compound, and a diol compound.

(5) A carboxyl group-containing polyurethane resin obtained by adding a compound having 1 hydroxyl group and 1 or more (meth) acryloyl groups in the molecule, such as hydroxyalkyl (meth) acrylate, to the synthesis of the resin of the above (2) or (4) and subjecting the resultant resin to terminal (meth) acrylation.

(6) A carboxyl group-containing polyurethane resin obtained by adding a compound having 1 isocyanate group and 1 or more (meth) acryloyl groups in the molecule, such as an equimolar reactant of isophorone diisocyanate and pentaerythritol triacrylate, to the synthesis of the resin of the above (2) or (4), and subjecting the resultant resin to terminal (meth) acrylation.

(7) A carboxyl group-containing resin obtained by reacting a multifunctional epoxy resin with (meth) acrylic acid, and adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, or the like to a hydroxyl group present in a side chain.

(8) A carboxyl group-containing resin is obtained by reacting a (meth) acrylic acid with a polyfunctional epoxy resin obtained by epoxidizing the hydroxyl groups of a 2-functional epoxy resin with epichlorohydrin, and adding a dibasic acid anhydride to the hydroxyl groups thus formed.

(9) A carboxyl group-containing polyester resin obtained by reacting a dicarboxylic acid with a polyfunctional oxetane resin and adding a dibasic acid anhydride to the primary hydroxyl group formed.

(10) A carboxyl group-containing resin is obtained by reacting a compound having a plurality of phenolic hydroxyl groups in 1 molecule with an alkylene oxide such as ethylene oxide or propylene oxide to obtain a reaction product, reacting the reaction product with an unsaturated group-containing monocarboxylic acid, and reacting the reaction product obtained thereby with a polybasic acid anhydride.

(11) A carboxyl group-containing resin is obtained by reacting a compound having a plurality of phenolic hydroxyl groups in 1 molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate to obtain a reaction product, reacting the reaction product with an unsaturated group-containing monocarboxylic acid, and reacting the reaction product obtained thereby with a polybasic acid anhydride.

(12) A carboxyl group-containing resin obtained by reacting an epoxy compound having a plurality of epoxy groups in 1 molecule with a compound having at least 1 alcoholic hydroxyl group and 1 phenolic hydroxyl group in 1 molecule such as p-hydroxyphenylethanol, and an unsaturated group-containing monocarboxylic acid such as (meth) acrylic acid, and reacting the alcoholic hydroxyl group of the obtained reaction product with a polybasic acid anhydride such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, adipic anhydride, and the like.

(13) An alkali-soluble polyimide resin obtained by reacting a carboxylic acid anhydride containing a carboxyl group and/or a phenolic hydroxyl group with an amine such as an amine containing a carboxyl group and/or a phenolic hydroxyl group, and optionally with another carboxylic acid anhydride, amine or isocyanate.

(14) The alkali-soluble resin described in (1) to (13) above, wherein a compound having 1 epoxy group and 1 or more (meth) acryloyl groups in the molecule, such as glycidyl (meth) acrylate and α -methyl glycidyl (meth) acrylate, is further added to the alkali-soluble resin.

Among the above alkali-soluble resins, the alkali-soluble resin formed using the resin of (7) and (14) is preferably used for the filler-filled layer (a) from the viewpoints of developability and resolution. From the viewpoint of discoloration resistance, an alkali-soluble resin formed using the resin of (1) and (14) is preferably used, and particularly preferably used for the second further purpose. The alkali-soluble resin described in (10) is preferably used from the viewpoint of insulation reliability, and is particularly preferably used for the third further purpose.

In the present specification, (meth) acrylate is a term generically used for acrylate, methacrylate, and a mixture thereof, and the same applies to other similar expressions.

Since the alkali-soluble resin has a plurality of hydrophilic groups such as carboxyl groups in the side chains of the main chain polymer, development with an aqueous alkali solution is possible.

The acid value of the alkali-soluble resin having a carboxyl group is suitably in the range of 40 to 200mgKOH/g, more preferably in the range of 45 to 120 mgKOH/g. When the acid value of the carboxyl group-containing resin is within the above range, the alkali solubility is good, and patterning by alkali development becomes easy.

The weight average molecular weight of the alkali-soluble resin varies depending on the resin skeleton, and is usually in the range of 2000 to 150000, more preferably 3000 to 100000, still more preferably 5000 to 100000. When the weight average molecular weight is within the above range, the developing speed in the developing step is well balanced with the development resistance of the pattern portion.

The content of the alkali-soluble resin is suitably in the range of 10 to 75 mass%, preferably 15 to 75 mass%, more preferably 20 to 70 mass% of the total components of the filler-filled layer (a) excluding the organic solvent. When the content of the alkali-soluble resin is preferably 15 to 75% by mass, more preferably 20 to 70% by mass, a cured film having high adhesion to a substrate and excellent toughness can be obtained. In the second further object, the content of the alkali-soluble resin is preferably 15% by mass or more, more preferably 20% by mass or more, and the film strength is good, while the viscosity of the composition is preferably 75% by mass or less, more preferably 70% by mass or less, and the coating property and the like are good. In the third further object, the content of the alkali-soluble resin is preferably 10 to 45 mass%, more preferably 15 to 40 mass%, and the coating strength is good when the content is 10 mass% or more, so that the viscosity of the composition is preferably not too high when the content is 45 mass% or less, and the coating property is good.

(thermally reactive Compound)

As the heat-reactive compound, a known and commonly used compound having a functional group capable of undergoing a heat curing reaction such as a cyclic (thio) ether group is used. Particularly, a compound which undergoes a thermosetting reaction with the alkali-soluble resin contained in the filler-filled layer (a) is preferable, and an epoxy resin is suitably used. The heat-reactive compound may be used alone or in combination of 2 or more.

Examples of the epoxy resin include bisphenol a type epoxy resin, brominated epoxy resin, novolac type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol a type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, alicyclic epoxy resin, triphenylmethane type epoxy resin, xylenol type or biphenol type epoxy resin or a mixture thereof, bisphenol S type epoxy resin, bisphenol a type novolac epoxy resin, heterocyclic type epoxy resin, biphenyl novolac type epoxy resin, naphthalene group-containing epoxy resin, and epoxy resin having dicyclopentadiene skeleton.

The content of the thermally reactive compound is preferably 70 mass% or less, more preferably 5 to 60 mass% of the total components of the filler-filled layer (a) excluding the organic solvent. If the content of the thermally reactive compound is 70 mass% or less, development residue of the unexposed portion in the developer is less likely to occur. However, in the third further object, it is preferably 40 mass% or less, more preferably 2 to 30 mass%, and development residue due to a decrease in solubility of an unexposed portion in the developer is less likely to occur.

(Low molecular weight Compound having unsaturated double bond capable of radical polymerization)

The filler-filled layer (a) may contain a low molecular weight compound having an unsaturated double bond capable of undergoing radical polymerization to adjust the viscosity of the resin composition, promote photocurability, and improve developability. The molecular weight of such a low molecular weight compound is, for example, 1000 or less.

Examples of the low molecular weight compound having an unsaturated double bond capable of undergoing radical polymerization include (meth) acrylate monomers such as polyester (meth) acrylate, polyether (meth) acrylate, urethane (meth) acrylate, carbonate (meth) acrylate, and epoxy (meth) acrylate. Specific examples of the compound include hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; diacrylates of alcohols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; acrylamides such as N, N-dimethylacrylamide, N-methylolacrylamide, N-dimethylaminopropyl acrylamide, and the like; aminoalkyl acrylates such as N, N-dimethylaminoethyl acrylate and N, N-dimethylaminopropyl acrylate; polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol and tris-hydroxyethyl isocyanurate, and polyhydric acrylic esters such as an ethylene oxide adduct, propylene oxide adduct and epsilon-caprolactone adduct thereof; a phenoxy acrylate, bisphenol a diacrylate, and a polyvalent acrylate such as an ethylene oxide adduct or a propylene oxide adduct of these phenols; polyglycidyl ethers such as diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether and triglycidyl isocyanurate; not limited to the above, at least 1 of an acrylic ester or melamine acrylic ester obtained by directly acrylating a polyol such as a polyether polyol, a polycarbonate diol, a hydroxyl-terminated polybutadiene, or a polyester polyol, or by acrylating a urethane with a diisocyanate, and each of the methacrylic esters corresponding to the above acrylic ester. The low molecular weight compound having an unsaturated double bond capable of radical polymerization may be used alone or in combination of 1 or more than 2.

The content of the low molecular weight compound having an unsaturated double bond capable of undergoing radical polymerization is preferably 0 to 50% by mass, more preferably 1 to 50% by mass, and still more preferably 3 to 30% by mass, of the total components of the filler-filled layer (a) excluding the organic solvent. When the content of the low molecular weight compound is 1 mass% or more, development resistance is easily obtained by light irradiation, and resolution is further improved. On the other hand, when 50 mass% or less, the cured coating film is excellent in flexibility. However, in the third further object, the proportion is preferably 1 to 40% by mass, more preferably 2 to 30% by mass, and still more preferably 3 to 20% by mass. When the content of the low molecular weight compound is 1 mass% or more, development resistance is easily obtained by light irradiation, and resolution is further improved. On the other hand, when 40 mass% or less, the cured coating film is excellent in flexibility.

(photopolymerization initiator)

From the viewpoint of resolution, the filler-filled layer (a) contains substantially no photopolymerization initiator. Here, substantially free of photopolymerization initiator means: the filler-filled layer (a) does not have photopolymerization in the individual layers, and is not excluded in the case of being contained in a small amount within a range not impairing photopolymerization. For example, a case where the photopolymerization initiator contained in the protective layer (B) is transferred to the ester filler-filled layer (a) is also considered, but even in this case, it is preferable that the concentration of the photopolymerization initiator contained in the protective layer (B) is 50% or less.

(antioxidant)

The filler-filled layer (a) may contain an antioxidant, and can give a cured product excellent in electroless gold plating resistance and discoloration resistance after reflow soldering.

Examples of the antioxidant include hindered phenol compounds such as 2, 6-dialkylphenol derivatives, 2-valent sulfur compounds, and phosphite compounds containing 3-valent phosphorus atoms. The antioxidant may be used alone or in combination of at least 2.

The content of the antioxidant is preferably in the range of 0.1 to 10 mass% in the entire components of the filler-filled layer (a) excluding the organic solvent.

(polymerization inhibitor)

From the viewpoint of resolution, the filler-filled layer (a) may contain a polymerization inhibitor.

Examples of the polymerization inhibitor include phenothiazine, hydroquinone, N-phenylnaphthylamine, chloranil, pyrogallol, benzoquinone, t-butylcatechol, hydroquinone, methylhydroquinone, t-butylhydroquinone, hydroquinone monomethyl ether, catechol, pyrogallol, naphthoquinone, 4-methoxy-1-naphthol, 2-hydroxy-1, 4-naphthoquinone, a phosphorus-containing compound having a phenolic hydroxyl group, and a nitrosamine compound. The polymerization inhibitor may be used alone or in combination of at least 1 kind and at least 2 kinds.

The content of the polymerization inhibitor in the filler-filled layer (a) is preferably 5 mass% or less of the total components of the filler-filled layer (a) except the organic solvent.

Protective layer (B)

The protective layer (B) is preferably formed of a photosensitive curable resin composition having a filler content less than that of the filler-filled layer (a), and more preferably formed of a photosensitive curable resin composition further comprising an alkali-soluble resin, a photopolymerization initiator, and a thermally reactive compound.

(alkali-soluble resin)

The alkali-soluble resin may be used alone or in combination of 1 or more than 2 kinds. Among these, the alkali-soluble resin of (7) and (14) is preferably used from the viewpoint of developability and resolution, and the alkali-soluble polyimide resin of (13) and (14) is more preferably used from the viewpoint of heat resistance and mechanical properties. In addition, in the second further object, the alkali-soluble resin of (7) and (14) is preferably used from the viewpoint of developing property and resolution, the alkali-soluble resin of (1) and (14) is preferably used from the viewpoint of discoloration resistance, and the alkali-soluble polyimide resin of (13) and (14) is more preferably used from the viewpoint of heat resistance, mechanical properties and resolution. In the third further object, the alkali-soluble resin of (7) and (14) is preferably used from the viewpoint of developability and resolution, the alkali-soluble polyimide resin formed using the resin of (13) and (14) is preferably used from the viewpoint of heat resistance, mechanical properties and resolution, and the alkali-soluble resin of (10) is preferably used from the viewpoint of insulation reliability.

The content of the alkali-soluble resin is preferably 10 to 75% by mass, more preferably 15 to 75% by mass, and still more preferably 20 to 70% by mass, of the total components of the protective layer (B) excluding the organic solvent. When the content is 15% by mass or more, the toughness of the cured coating film is improved. In addition, when the content is 75 mass% or less, damage such as scratches is less likely to occur on the surface during the development step. However, in the third further object, it is preferable that the toughness of the cured coating film is improved when the content of the resin is 10 to 75 mass%, more preferably 15 to 70 mass%, and the content of the resin is not more than 10 mass%, and it is difficult to cause damage such as scratches on the surface during the development step when the content of the resin is not more than 75 mass%.

(photopolymerization initiator)

The photopolymerization initiator may be used alone or in combination of 2 or more. As the photopolymerization initiator, 1 or more photopolymerization initiators selected from the group consisting of oxime ester photopolymerization initiators having an oxime ester group, α -aminoacetophenone photopolymerization initiators, and acylphosphine oxide photopolymerization initiators can be suitably used.

As the oxime ester photopolymerization initiator, there may be mentioned, for example, CGI-325, irgacure OXE01, irgacure OXE02, N-1919 and NCI-831 manufactured by ADEKA, inc. of BASF Japan Co., ltd. In addition, a photopolymerization initiator having 2 oxime ester groups in the molecule can also be suitably used.

The content of the oxime ester photopolymerization initiator is preferably 0.01 to 20 parts by mass based on 100 parts by mass of the alkali-soluble resin. When the amount is 0.01 parts by mass or more, coating properties such as chemical resistance are good. On the other hand, if the amount is 20 parts by mass or less, the light absorption on the surface of the coating film is not excessively rapid, and deep curing becomes good. More preferably 0.5 to 15 parts by mass.

Specific examples of the α -aminoacetophenone photopolymerization initiator include 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholino-1-propanone, 2-benzil-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, 2- (dimethylamino) -2- [ (4-methylphenyl) methyl ] -1- [4- (4-morpholino) phenyl ] -1-butanone, and N, N-dimethylaminoacetophenone. Commercially available products include Omnirad 907, omnirad 369, and Omnirad 379 manufactured by GM Resins.

Specific examples of the acylphosphine oxide photopolymerization initiator include 2,4, 6-trimethylbenzoyl diphenyl phosphine oxide, bis (2, 4, 6-trimethylbenzoyl) -phenyl phosphine oxide, bis (2, 6-dimethoxybenzoyl) -2, 4-trimethyl-pentylphosphine oxide, and the like. Examples of the commercial products include Lucirin TPO manufactured by BASF corporation, omnirad 819 manufactured by IGM Resins, and the like.

The content of the α -aminoacetophenone photopolymerization initiator and the acylphosphine oxide photopolymerization initiator is preferably 0.01 to 15 parts by mass based on 100 parts by mass of the alkali-soluble resin. When the amount is 0.01 parts by mass or more, the coating film characteristics such as chemical resistance are similarly good. On the other hand, if the amount is 15 parts by mass or less, outgas is reduced, and further light absorption at the surface of the coating film does not become excessively rapid, and deep curing becomes good. More preferably 0.5 to 10 parts by mass.

Here, as the photopolymerization initiator to be used, in the case of a catalyst for polymerization reaction of a thermally reactive compound to be described later, the above-mentioned oxime ester-based photopolymerization initiator and α -aminoacetophenone-based photopolymerization initiator are preferable from the viewpoint of generation of not only a photoradical but also an alkaline substance by irradiation with light, and among them, oxime ester-based photopolymerization initiators are more preferable from the viewpoint of excellent resolution.

(thermally reactive Compound)

The heat-reactive compound may be used alone or in combination of 1 or more than 2. Particularly, a compound which undergoes a thermal curing reaction with the alkali-soluble resin contained in the protective layer (B) is preferable, and the epoxy resin is suitably used.

The content of the thermally reactive compound is preferably 3 to 50% by mass, more preferably 5 to 40% by mass, based on the total components of the protective layer (B) excluding the organic solvent. When the content is 3% by mass or more, the toughness of the coating film is obtained, and when the content is 50% by mass or less, good developability is obtained.

(antioxidant)

The protective layer (B) may contain an antioxidant. The antioxidant may be used alone or in combination of 1 or more than 2. A cured product excellent in electroless gold plating resistance and discoloration resistance after reflow soldering can be obtained.

The content of the antioxidant is preferably in the range of 0.1% to 10% of the total components of the protective layer (B) excluding the organic solvent.

(Filler)

The protective layer (B) may contain a filler. The filler may be used alone or in combination of 1 or more than 2 kinds. The filler of the protective layer (B) may be selected from the same types and shapes as those used for the filler-filled layer (a), or may be selected from different types and shapes.

The filler content of the protective layer (B) may be 25 mass% or less of the filler content of the filler-filled layer (a), or may be omitted.

The content of the filler in the protective layer (B) is preferably 0 to 20% by mass, more preferably 0 to 15% by mass, still more preferably 0 to 10% by mass, and particularly preferably 0 to 5% by mass, of the total components in the protective layer (B) excluding the organic solvent.

In a second further object, the protective layer (B) may contain titanium oxide. The titanium oxide may be used alone or in combination of 1 or more than 2 kinds. The content of titanium oxide in the protective layer (B) may be 20 mass% or less of the content of titanium oxide contained in the filler-filled layer (a), or may be omitted. The content of titanium oxide in the protective layer (B) is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, of the total components in the protective layer (B) excluding the organic solvent. In addition, an inorganic filler may be blended in the protective layer (B) in addition to titanium oxide, but from the viewpoint of scratch resistance, the content of the inorganic filler other than titanium oxide is preferably 0 to 20 mass% in all components in the protective layer (B) other than the organic solvent.

In the third further object, the protective layer (B) does not contain a heat-dissipating filler having a thermal conductivity higher than 10W/m·k from the viewpoint of scratch resistance, but may be contained within a range that does not affect scratch resistance. That is, from the viewpoint of scratch resistance, the content of the heat-dissipating filler in the protective layer (B) must be 20 mass% or less with respect to the content of the heat-dissipating filler in the filler-filled layer (a). The heat-dissipating filler may be used alone or in combination of 1 or more than 2. The content of the heat-dissipating filler in the protective layer (B) is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, of the total components in the protective layer (B) excluding the organic solvent. The inorganic filler may be blended in the protective layer (B) in addition to the heat-dissipating filler, but from the viewpoint of scratch resistance, the content of the inorganic filler other than the heat-dissipating filler is preferably 0 to 20 mass% in all components of the protective layer (B) other than the organic solvent.

The protective layer (B) may contain a low molecular weight compound having an unsaturated double bond capable of undergoing radical polymerization. The low molecular weight compound having an unsaturated double bond capable of radical polymerization may be used alone or in combination of 1 or more than 2.

However, from the viewpoint of resolution, the content of the low molecular weight compound having an unsaturated double bond capable of undergoing radical polymerization having a molecular weight of 1000 or less is preferably substantially not contained, for example, 0 to 20% by mass, preferably 0 to 15% by mass, more preferably 0 to 10% by mass, still more preferably 0 to 2% by mass, and particularly preferably 0% by mass, of the total components in the protective layer (B) excluding the organic solvent.

(polymerization inhibitor)

The protective layer (B) may contain the above polymerization inhibitor from the viewpoint of resolution.

The content of the polymerization inhibitor in the protective layer (B) is preferably 5 mass% or less of all components of the protective layer (B) except the organic solvent.

[ photosensitive laminate resin Structure ]

The photosensitive laminated resin structure of the present invention can be preferably used for forming a protective film of an electronic component, particularly a printed circuit board, and among them, can be preferably used for forming a permanent protective film such as a solder resist layer or a coverlay of a flexible printed circuit board. The printed wiring board is not particularly limited, and the photosensitive laminated resin structure of the present invention is preferably used for a package substrate in view of low thermal expansion and excellent adhesion, plating resistance, crack resistance and resolution. In the second further object, the printed circuit board is not particularly limited, and is preferably a printed circuit board on which a light emitting element such as an LED is mounted, in view of excellent reflectance. In the third further object, the printed circuit board is not particularly limited, and is preferably a package substrate or a surface-mounted light emitting diode in view of excellent heat dissipation.

In addition, in the second further object of the photosensitive laminated resin structure of the present invention, the structure can be preferably used for forming a reflective plate for a light emitting element such as an LED or Electroluminescence (EL) from the viewpoint of excellent reflectance.

The photosensitive laminated resin structure of the present invention preferably comprises a laminated filler layer (a) and a protective layer (B).

[ Dry film ]

The dry film of the present invention is characterized in that at least one surface of the photosensitive laminated resin structure of the present invention is supported or protected by a film. As a preferred embodiment, a dry film 10 having a 4-layer structure in which a protective film 14, a filler-filled layer (a) 13, a protective layer (B) 12, and a support film 11 are laminated in this order as shown in fig. 1 is used. The dry film of the present invention may be laminated so that the protective layer (B) is on the surface layer side, and the film peeled off during lamination may be a support film or a protective film, and therefore, the support film, the filler layer (a), the protective layer (B), and the protective film may be laminated in this order. The dry film of the present invention may be wound into a roll.

The dry film of the present invention can be produced, for example, as follows.

That is, first, the resin composition constituting the protective layer (B) and the resin composition constituting the filler-filled layer (a) are diluted with an organic solvent to be adjusted to have appropriate viscosities, and then sequentially coated on a support film (carrier film) by a known method such as a comma coater according to a conventional method. Thereafter, drying is usually carried out at a temperature of 50 to 140 ℃ for 1 to 30 minutes, whereby a dry film having a coating film of the protective layer (B) and the filler-filled layer (a) formed on the support film can be produced. For the purpose of preventing adhesion of dust to the surface of the coating film, a protective film (cover film) that can be peeled off may be laminated on the dry film. As the support film and the protective film, conventionally known plastic films can be suitably used, and when the protective film is peeled off, the adhesive force is preferably smaller than the adhesive force between the resin layer and the support film. The thicknesses of the support film and the protective film are not particularly limited, and are usually appropriately selected in the range of 10 to 150. Mu.m.

[ cured product ]

The cured product of the present invention is characterized by comprising the photosensitive laminated resin structure of the present invention. In the first object of the cured product of the present invention, the coefficient of thermal expansion (CTE. Alpha.1) before the glass transition temperature is preferably 40 ppm/DEG C or less, more preferably 30 ppm/DEG C or less. In the second further object, the Y value of the XYZ chromaticity system measured from the protective layer (B) side is preferably 70 or more, more preferably 75 or more, and still more preferably 80 or more. In addition, in the case of measuring the thermal conductivity of the cured product of the present invention by the periodic heating method, it is preferable that the cured product has a thermal conductivity of 1.5W/mK or more.

[ electronic component ]

The electronic component of the present invention is characterized by having the cured product of the present invention.

In the cured product of the present invention, it is preferable that the cured product is formed such that the protective layer (B) is the outermost layer in the electronic component of the present invention, from the viewpoint of excellent plating resistance and crack resistance, from the viewpoint of excellent scratch resistance and reflectance, and from the viewpoint of excellent scratch resistance.

[ method for manufacturing electronic component ]

As a method for manufacturing an electronic component using the photosensitive laminated resin structure of the present invention, an example of a method for manufacturing a printed circuit board will be described based on the steps shown in the process chart of fig. 2. Namely, the method comprises the following steps: the photosensitive laminated resin structure of the present invention is formed on a printed circuit board on which a conductor circuit is formed (lamination step), a step of patterning the photosensitive laminated resin structure by irradiation with active energy rays (exposure step), and a step of simultaneously forming a photosensitive laminated resin structure in which the photosensitive laminated resin structure is subjected to alkali development and patterning (development step). Further, if necessary, after alkali development, further photo-curing and thermal curing (post-curing step) are performed to completely cure the photosensitive laminated resin structure, whereby a highly reliable printed wiring board can be obtained. Further, if necessary, a step of heating the photosensitive laminated resin structure (PEB step) is added between the exposure step and the developing step, and the patterned photosensitive laminated resin structure can be formed simultaneously by the developing step. In particular, in the case where an alkali-soluble resin is used for the protective layer (B), this step is preferably used. Further, when the protective layer (B) contains a compound that generates an alkaline substance by light irradiation, the PEB step is preferably performed from the viewpoint of resolution.

[ laminating step ]

In this step, the printed circuit board 1 on which the conductor circuit 2 is formed can be formed by: the resin composition constituting the filler-filled layer (a) 3 and the protective layer (B) 4 is sequentially applied to the substrate and dried, whereby the filler-filled layer (a) 3 and the protective layer (B) 4 are directly formed, or the resin composition constituting the filler-filled layer (a) 3 and the protective layer (B) 4 are sequentially laminated on the substrate in the form of dry films. The laminate structure may be formed by laminating a dry film laminate structure having a 2-layer structure on a substrate. In this case, at least one surface of the laminated structure may be supported or protected by a film. As the film to be used, a plastic film that can be peeled from the laminated structure can be used. The thickness of the film is not particularly limited and is usually suitably selected in the range of 10 to 150. Mu.m. From the viewpoint of the strength of the coating film, the interface between the layers can be compatible. As the laminator, commercially available vacuum heating pressurizing laminators and the like can be used, and for example, vacuum pressurizing laminators manufactured by the company name machine, nichigo-morton co., ltd. Vacuum applicator and the like can be used, or they can be continuously performed. The lamination step may be performed by using each apparatus. In this case, a roll laminator, a vacuum pressurizing machine, or the like may be used in addition to the vacuum laminators described above. The vacuum press may be a commercially available conventional apparatus, and for example, a multistage press, a multistage vacuum press, a rapid press, continuous molding, an autoclave molding machine, etc. may be used. The above laminator and the like can be operated at 60 to 130℃and can be operated at a pressure of 0.1 to 0.7MPa for a heating and pressurizing time of 1 to 90 seconds, a vacuum degree of 10 to 10000Pa, and a vacuum time of 1 to 90 seconds.

[ Exposure procedure ]

In this step, the photopolymerization initiator contained in the protective layer (B) 4 or the filler-filled layer (a) 3 is activated into a negative pattern by irradiation with active energy rays, and the exposed portion is cured. As the exposure machine, an exposure machine equipped with a direct drawing device, a metal halide lamp, or the like can be used. For pattern-wise exposure the mask is a negative mask.

As the active energy ray used in the exposure, a laser beam having a maximum wavelength in the range of 350 to 450nm, scattered light, or parallel light is preferably used. By setting the maximum wavelength to this range, the photopolymerization initiator can be activated efficiently. The exposure amount varies depending on the film thickness, but may be generally 50 to 1500mJ/cm ² 。

[ developing Process ]

In this step, the unexposed portion is removed by alkali development, and a negative pattern-like protective film, particularly a cap layer and a solder resist layer, is formed. The developing method may be a known method such as dipping. As the developer, an aqueous alkali solution such as an aqueous solution of an imidazole such as sodium carbonate, potassium hydroxide, amines, or 2-methylimidazole, or an aqueous alkali solution such as an aqueous tetramethylammonium hydroxide solution (TMAH), or a mixture thereof may be used.

[ post-curing Process ]

The protective film may be further irradiated with light after the development step, or may be heated at 150 ℃ or higher, for example. The heating temperature is, for example, 80 to 170℃and the heating time is 5 to 100 minutes. Since the curing of the photosensitive laminated resin structure of the present invention is, for example, a ring-opening reaction of an epoxy resin by a thermal reaction, strain and curing shrinkage can be suppressed as compared with the case where curing is performed by a photo radical reaction.

In the PEB step, the photosensitive laminated resin structure is heated between the exposure step and the development step, so that the exposed portion can be cured. The heating temperature is, for example, 70 to 140℃and the heating time is 2 to 100 minutes.

Examples

Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to the examples. In the following, "parts" and "%" are all based on mass unless otherwise specified.

Synthesis example 1 of alkali-soluble resin

220 parts of cresol novolak type epoxy resin (EPICLON N-695, epoxy equivalent: 220, manufactured by DIC Co., ltd.) was placed in a four-necked flask equipped with a stirrer and a reflux condenser, and 214 parts of carbitol acetate was added thereto to dissolve the epoxy resin under heating. Next, 0.1 part of hydroquinone as a polymerization inhibitor and 2.0 parts of dimethylbenzyl amide as a reaction catalyst were added. The mixture was heated to 95-105℃and 72 parts of acrylic acid was slowly added dropwise thereto and reacted for 16 hours. The reaction product is cooled to 80-90 ℃, 106 parts of tetrahydrophthalic anhydride is added for reaction for 8 hours, and the reaction product is taken out after cooling.

The resin solution of the photosensitive resin having both an ethylenically unsaturated bond and a carboxyl group thus obtained was as follows: 65% of nonvolatile components, 100mgKOH/g of acid value of solid material and about 3500 of weight-average molecular weight Mw.

The weight average molecular weight of the obtained resin was measured by high performance liquid chromatography with connected Pump LC-804, KF-803, KF-802 manufactured by Shimadzu corporation.

Synthesis example 2 of alkali-soluble resin

6.98g of 2, 2-bis [4- (4-aminophenoxy) phenyl ] propane (hereinafter referred to as "BAPP"), 3.80g of 3, 5-diaminobenzoic acid, 8.21g of JEFFAMINE XTJ-542 (manufactured by Huntsman Co., ltd., molecular weight 1025.64), and 86.49g of gamma-butyrolactone were charged into a four-necked 300mL flask equipped with a nitrogen inlet pipe, a thermometer, and a stirrer, and dissolved therein at room temperature.

Then, 17.84g of cyclohexane-1, 2, 4-tricarboxylic acid-1, 2-anhydride and 2.88g of trimellitic anhydride were charged, and the mixture was kept at room temperature for 30 minutes. 30g of toluene was further charged, the temperature was raised to 160℃and the water formed with toluene was removed, followed by holding for 3 hours and cooling to room temperature, whereby an imide solution was obtained.

To the obtained imide solution, 9.61g of trimellitic anhydride and 17.45g of trimethylhexamethylene diisocyanate were charged, and the mixture was kept at 160℃for 32 hours. Thus, a resin solution containing 40.1% (nonvolatile matter) of the carboxyl group-containing polyamideimide resin was obtained. The acid value of the solid content was 83.1mgKOH/g.

Synthesis example 3 of alkali-soluble resin

Into a2 liter-volume separable flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and a nitrogen inlet tube, 900g of diethylene glycol dimethyl ether and 21.4g of t-butyl peroxy-2-ethylhexanoate (Perbutyl O manufactured by Nikko Co., ltd.) were charged, and after heating to 90℃the mixture was added together with 21.4g of bis (4-t-butylcyclohexyl) peroxydicarbonate (Peronyl TCP manufactured by Nikko Co., ltd.) to 309.9g of methacrylic acid, 116.4g of methyl methacrylate, and 109.8g of lactone-modified 2-hydroxyethyl methacrylate (Daicel Corporation: PLACCEL FM 1) by Nikko Co., ltd.) dropwise over 3 hours, followed by further aging for 6 hours, to obtain a carboxyl group-containing copolymer resin solution. The reaction was carried out under nitrogen atmosphere.

Subsequently, 363.9g of 3, 4-epoxycyclohexylmethacrylate (Cyclomer A200, manufactured by Daicel Corporation), 3.6g of dimethylbenzoyl amide and 1.80g of hydroquinone monomethyl ether were added to the carboxyl group-containing copolymer resin solution, and the mixture was heated to 100℃and stirred to carry out ring-opening addition reaction of epoxy. After 16 hours, a resin solution of 53.8% (nonvolatile matter) of a photosensitive copolymer resin having both an ethylenically unsaturated bond and a carboxyl group was obtained, which contained a solid content acid value=108.9 mgKOH/g and a weight average molecular weight=25000 (styrene conversion).

Example 1

< adjustment of inorganic filler >

(slurrying of inorganic Filler X)

50g of spherical silica particles (SO-C2, average particle diameter: 500nm, manufactured by Admatechs Co., ltd.), 48g of PMA as a solvent, and 2g of a silane coupling agent having a methacryloyl group (KBM-503, manufactured by Xinyue chemical Co., ltd.) were uniformly dispersed to obtain a silica slurry (silica component 50 mass%) treated with methacryloyl silane.

(sizing of inorganic Filler Y)

50g of spherical silica particles (SO-C2, average particle diameter: 500nm, manufactured by Admatechs Co., ltd.), 48g of PMA as a solvent, and 2g of a silane coupling agent having an epoxy group (KBM-403, manufactured by Xinyue chemical Co., ltd.) were uniformly dispersed to obtain an epoxy silane-treated silica slurry (silica component 50 mass%).

(sizing of inorganic Filler Z)

50g of spherical silica particles (SO-C2, average particle diameter: 500nm, manufactured by Admatechs Co.), 48g of PMA as a solvent, and 2g of a dispersant (BYK-111) were uniformly dispersed to obtain a silica slurry without surface treatment (silica component, 50 mass%).

< preparation of resin composition >

The materials described in examples and comparative examples were mixed according to the formulations described in table 1 below, and after premixing in a mixer, the photosensitive resin compositions having the compositions shown in table 1 as the protective layer (B) and the alkali-soluble resin compositions having the compositions shown as the filler-filled layer (a) were prepared by three-roll milling. The values in the table are not particularly limited as long as they are parts by mass and are other than the organic solvent.

< preparation of Dry film having photosensitive laminate resin Structure >

Using each of the resin combinations described in table 1 obtained above, a photosensitive laminated resin structure was produced as follows. First, a photosensitive resin composition having the composition shown in table 1 as a protective layer (B) was coated on a polyethylene terephthalate (PET) support film having a thickness of 35 μm, and dried to prepare a dry film having the protective layer (B). Then, an alkali-soluble resin composition having the composition shown in table 1 as a filler-filled layer (a) was applied onto the protective layer (B) and dried to prepare a dry film having the filler-filled layer (a). Then, a biaxially stretched polypropylene film having a thickness of 15 μm was laminated on the surface of the filler-filled layer (a), and a dry film composed of 4 layers of a support film (PET film), a protective layer (B), the filler-filled layer (a), and a protective film (OPP film) was produced. However, in comparative example 1-1, a dry film composed of 3 layers of a support film, a filler-filled layer (a), and a protective film was produced.

TABLE 1

*1-1: the resin solution of the photosensitive resin having both an ethylenically unsaturated bond and a carboxyl group obtained in Synthesis example 1

*1-2: resin solution of Polyamide-imide resin obtained in Synthesis example 2

*1-3: dipentaerythritol hexaacrylate (manufactured by Japanese chemical Co., ltd.)

*1-4: bisphenol A type novolak epoxy resin (DIC Co., ltd.)

*1-5: tetramethyl biphenol epoxy resin (Mitsubishi chemical Co., ltd.)

*1-6: oxime ester photopolymerization initiator (BASF Co., ltd.)

*1-7: silica slurry treated with methacryloyl silane (described as mass parts of silica in the table)

*1-8: silica slurry treated with epoxysilane (shown in Table as mass part of silica)

*1-9: silica slurry without surface treatment agent (the mass parts of silica are shown in the table)

The photosensitive laminated resin structures were evaluated as follows using the dry films of examples 1-1 to 1-9 and comparative examples 1-1 to 1-4 prepared as described above.

(optimal exposure)

A single-sided printed circuit board having a copper thickness of 15 μm and a circuit formed thereon was prepared, and pretreatment was performed using MEC co., ltd. The protective film in contact with the filler-filled layer (A) in each dry film of the foregoing examples and comparative examples was peeled offAnd (c) bonding the filler-filled layer (a) to the substrate by using a vacuum laminator so that the filler-filled layer (a) is in contact with the substrate, thereby forming a photosensitive laminated resin structure on the substrate. The substrate was exposed to light by means of a Stuffer 41-stage exposure meter (Kodak No. 2) using an exposure apparatus equipped with a high-pressure mercury lamp (short arc lamp), heated at 100℃for 30 minutes after exposure, and then the PET film in contact with the protective layer (B) was peeled off, and developed for 60 seconds (30℃0.2MPa, 1wt% Na) ₂ CO ₃ Aqueous solution), the pattern of the Stuffer41 level step exposure meter remaining at the time of 5 levels was used as the optimum exposure amount.

(determination of CTE)

An electrolytic copper foil having a thickness of 9 μm was prepared, and the protective film in contact with the filler-filled layer (A) was peeled off from the dry films of examples 1-1 to 1-9 and comparative examples 1-1 to 1-4, and the film was bonded to the glossy surface of the electrolytic copper foil using a vacuum laminator so that the filler-filled layer (A) was in contact with the glossy surface of the electrolytic copper foil, thereby forming a photosensitive laminated resin structure on the electrolytic copper foil. Then, the entire surface of the photosensitive laminated resin structure was exposed to light at the optimum exposure amount by using an exposure apparatus equipped with a high-pressure mercury lamp, baked at 100℃for 30 minutes, and then peeled off the PET film in contact with the protective layer (B), developed for 60 seconds with a 1wt% aqueous sodium carbonate solution at 30℃under a jet pressure of 0.2MPa, and further subjected to cumulative exposure amount of 1000mJ/cm in a UV conveyor furnace ² After ultraviolet irradiation, the cured product was heated at 150℃for 60 minutes. Thereafter, the copper foil of the electrolytic copper foil was etched and removed using an etchant having a composition of 340g/l copper chloride and a free hydrochloric acid concentration of 51.3g/l, and the resulting film was sufficiently washed with water and dried to prepare a cured film formed of each photosensitive laminated resin structure.

For each of the above cured films, the average linear thermal expansion coefficient when the temperature was changed from-30℃to 250℃was measured using TMA-Q400EM (width of sample 5mm, measuring jig interval 15mm, and load was recorded as film thickness (. Mu.m). Times.0.5 g weight) manufactured by TA Instruments Co.

(evaluation of resolution (evaluation of minimum opening diameter))

A single-sided printed circuit board with a copper thickness of 15 μm was prepared and MEC Co was used.Ltd. CZ 8100. The protective films in contact with the filler-filled layer (a) in the dry films of examples 1-1 to 1-9 and comparative examples 1-1 to 1-4 were peeled off, and the protective films were bonded to each other with a vacuum laminator so that the filler-filled layer (a) was in contact with the substrate, thereby forming a photosensitive laminated resin structure on the substrate. On the substrate, a negative pattern having a via hole opening diameter of 500 μm, 300 μm, 150 μm, 100 μm, 80 μm was formed as a negative mask for resolution evaluation, and the mask was patterned by using an exposure apparatus equipped with a high-pressure mercury lamp, and baked at 100℃for 30 minutes, and then the PET film in contact with the protective layer (B) was peeled off, and developed for 60 seconds with a 1wt% sodium carbonate aqueous solution at 30℃under a jet pressure of 0.2MPa to obtain a solder resist pattern. The substrate was subjected to a cumulative exposure of 1000mJ/cm in a UV conveyor oven ² After ultraviolet irradiation, the resultant was heated at 150℃for 60 minutes and cured to prepare test pieces each having a cured product of each photosensitive laminated resin structure.

In each of the obtained test pieces, the pattern opening was observed by SEM, and the minimum opening diameter was evaluated.

(resistance to electroless gold plating)

The test pieces of examples 1-1 to 1-9 and comparative examples 1-1 to 1-4 described above (resolution evaluation) were subjected to plating under conditions of 0.5 μm nickel and 0.03 μm gold using a commercially available electroless nickel plating bath and electroless gold plating bath, and the presence or absence of delamination of the laminated resin structure and the presence or absence of plating penetration were evaluated based on tape delamination, and then the presence or absence of delamination of the laminated resin structure was evaluated based on tape delamination. The criterion is as follows.

O: no penetration and peeling were observed.

Delta: slightly penetrated after plating was confirmed, but the tape was peeled off without peeling off.

X: the plating is followed by stripping.

(evaluation of adhesion)

In the test pieces of examples 1-1 to 1-9 and comparative examples 1-1 to 1-4 described above (resolution evaluation), checkered cuts were made in the cured product on the test piece at 1mm intervals by a cutter, and after the cellophane tape was adhered, the cellophane tape was peeled off, and the state of the cured product remaining on the test piece was evaluated according to the following determination criteria.

O: without separation.

X: the number of separations was 5 or more.

(evaluation of crack resistance)

A 2mm copper wire patterned substrate was prepared and subjected to pretreatment using MEC co., ltd. CZ 8100. The photosensitive laminated resin structures were formed on the substrate using the dry films of examples 1-1 to 1-9 and comparative examples 1-1 to 1-4, in the same manner as described in the above-described (resolution evaluation (minimum opening diameter evaluation)). Then, a mask pattern was obtained by forming a 3mm square opening pattern on the copper wire of the substrate through a negative pattern having a 3mm square negative pattern as a negative mask for crack resistance evaluation, performing pattern exposure at the optimum exposure amount using an exposure apparatus equipped with a high-pressure mercury lamp, baking at 100 ℃ for 30 minutes, and then peeling off the PET film in contact with the protective layer (B), and developing under the same conditions as in the method described in the above (evaluation of resolution (evaluation of minimum opening diameter)), followed by curing by ultraviolet irradiation and heating.

The substrate for evaluation was put into a thermal cycler for temperature cycling between-65℃for 30 minutes and 175℃for 30 minutes, and TCT (Thermal Cycle Test) was carried out. Then, appearance at 600 cycles and 1000 cycles was observed by SEM, and occurrence of cracks was evaluated according to the following judgment criteria.

And (3) the following materials: there were no anomalies in 1000 cycles.

O: cracks occurred in 1000 cycles.

X: cracks occurred in 600 cycles.

(Low warpage)

A polyimide film (DU PONT-TORAY CO., LTD. Kapton 100H) having a thickness of 25 μm was prepared, and the protective film in contact with the filler-filled layer (A) was peeled off from the dry films of examples 1-1 to 1-9 and comparative examples 1-1 to 1-4, and the filler-filled layer (A) was bonded to one side of the polyimide film by a vacuum laminator so as to form a photosensitive laminated resin structure on the polyimide film. Then, using an exposure apparatus equipped with a high-pressure mercury lamp, the photosensitive laminated resin structure was subjected to surface-mount exposure at the optimum exposure amount, baked at 100 ℃ for 30 minutes, and then the PET film in contact with the protective layer (B) was peeled off, and developed under the same conditions as in the method described above (resolution evaluation (evaluation of minimum opening diameter)), and cured by ultraviolet irradiation and heating, to prepare a sample for evaluation of low warpage.

The sample for evaluating the low warpage was cut into 50mm×50mm, and the resultant was left standing on a horizontal table, and the height of warpage at angle 4 was measured, and an average value was obtained, and evaluated according to the following criteria.

O: the warpage is lower than 4 mm.

Delta: the warpage is 4mm or more and less than 8 mm.

X: the warp is 8mm or more.

As is clear from the evaluation results shown in the above tables, the photosensitive laminated resin structures of examples 1-1 to 1-9 have low CTE, and also have good adhesion, plating resistance, resolution, and crack resistance.

Example 2

< preparation of resin composition >

The materials described in table 2 were mixed according to the formulations described in table 2, and after premixing in a mixer, the resin compositions were prepared by kneading with a three-roll mill. The values in the table are not particularly limited as long as they are parts by mass and are other than the organic solvent.

TABLE 2

*2-1: the resin solution of the carboxyl group-containing resin obtained in Synthesis example 1

*2-2: the resin solution of the carboxyl group-containing resin obtained in the above Synthesis example 3

*2-3: the resin solution of the carboxyl group-containing resin obtained in Synthesis example 2

*2-4: dipentaerythritol hexaacrylate (manufactured by Japanese chemical Co., ltd.)

*2-5: bisphenol A type novolak epoxy resin (DIC Co., ltd.)

*2-6: tetramethyl biphenol epoxy resin (Mitsubishi chemical Co., ltd.)

*2-7: oxime ester photopolymerization initiator (BASF Co., ltd.)

*2-8: titanium oxide (TIPAQUE CR-90 manufactured by Shichen Co., ltd.)

*2-9: hindered phenol compound (BASF Co., ltd.)

*2-10: hydroquinone compound (manufactured by Chuangkou chemical Co., ltd.)

< preparation of Dry film having photosensitive laminate resin Structure >

Using the resin compositions 2-1 to 2-14 obtained as described above, a photosensitive laminated resin structure was produced as follows. First, the composition of table 2 corresponding to the protective layer (B) shown in tables 3 and 4 was applied to a polyethylene terephthalate (PET) support film having a thickness of 35 μm and dried to prepare a dry film having the protective layer (B). Then, the composition of table 2 corresponding to the filler-filled layer (hereinafter referred to as a colored layer (a)) shown in tables 3 and 4 was applied onto the protective layer (B) and dried to prepare a dry film having the colored layer (a). Then, a biaxially oriented polypropylene (OPP) film 15 μm thick was laminated on the surface of the colored layer (a), and a dry film composed of 4 layers of a support film (PET film), a protective layer (B), the colored layer (a), and a protective film (OPP film) was produced. However, dry films comprising the support film, the protective layer (B), and the protective film were produced for comparative examples 2 to 4, and dry films comprising 3 layers of the support film, the colored layer (a), and the protective film were produced for comparative examples 2 to 5.

TABLE 3

TABLE 4

The photosensitive laminated resin structures were evaluated as follows using the dry films of examples 2-1 to 2-14 and comparative examples 2-1 to 2-5 prepared as described above.

(optimal exposure)

A single-sided printed circuit board having a copper thickness of 15 μm and a circuit formed thereon was prepared, and pretreatment was performed using MEC co., ltd. The protective film in contact with the colored layer (a) was peeled off from each of the dry films of the examples and comparative examples, and the colored layer (a) was bonded to the substrate by using a vacuum laminator so as to form a photosensitive laminated resin structure on the substrate. The substrate was exposed to light by means of a Stuffer 41-stage exposure meter (Kodak No. 2) using an exposure apparatus equipped with a high-pressure mercury lamp (short arc lamp), heated at 100℃for 30 minutes after exposure, and then the PET film in contact with the protective layer (B) was peeled off, and developed for 60 seconds (30℃0.2MPa, 1wt% Na) ₂ CO ₃ Aqueous solution), the pattern of the Stuffer41 level step exposure meter remaining at the time of 5 levels was used as the optimum exposure amount.

(measurement of reflectance)

A single-sided printed circuit board having a copper thickness of 15 μm and a circuit formed thereon was prepared, and pretreatment was performed using MEC co., ltd. The protective films in contact with the colored layer (a) in the dry films of examples 2-1 to 2-14 and comparative examples 2-1 to 2-5 were peeled off, and the colored layer (a) was bonded to the substrate by using a vacuum laminator so as to form a photosensitive laminated resin structure on the substrate. The substrate was subjected to full-face exposure at an optimum exposure amount using an exposure apparatus equipped with a high-pressure mercury lamp, heated at 100℃for 30 minutes, and then peeled off the PET film in contact with the protective layer (B), developed for 60 seconds with a 1wt% aqueous sodium carbonate solution at 30℃under a jet pressure of 0.2MPa, heated at 150℃for 60 minutes, and cured to obtain a test piece for measuring reflectance. For each of the obtained test pieces, the Y value of the XYZ color system was measured using a color difference meter CR-400 manufactured by Minolta. (Y is the value of Y in the XYZ chromaticity system, and the larger the value is, the higher the reflectance is.)

The criterion is as follows.

And (3) the following materials: y value is greater than or equal to 80

And (2) the following steps: 80> Y value is not less than 75

Delta: 75> Y value is not less than 70

X: 70> Y value

(evaluation of resolution (evaluation of minimum opening diameter))

In the production of the test pieces of examples 2-1 to 2-14 and comparative examples 2-1 to 2-5 described above (measurement of reflectance), the test pieces for resolution evaluation were obtained by the same method as the production of the test pieces described above (measurement of reflectance) except that the pattern exposure was performed at the optimum exposure amounts through a negative mask having a negative pattern of via hole opening diameters of 500 μm, 300 μm, 150 μm, 100 μm, 80 μm as a negative mask for resolution evaluation. For each of the obtained test pieces, the pattern opening was observed using SEM, and the minimum opening diameter was evaluated.

(scratch resistance)

The test pieces of examples 2-1 to 2-14 and comparative examples 2-1 to 2-5 described above (measurement of reflectance) were each placed and fixed with a brass cylinder having a diameter of 1cm and a height of 2cm and a weight of 10g in this order, and the cylinder with the weight placed thereon was slid on the test piece at a speed of 1 cm/sec for 5cm to visually confirm whether or not a black scratch was generated on the test piece.

The criterion is as follows.

O: no scratch

X: scratch is generated

(resistance to electroless gold plating)

The test pieces of examples 2-1 to 2-14 and comparative examples 2-1 to 2-5 described above (resolution evaluation) were subjected to plating under conditions of 0.5 μm nickel and 0.03 μm gold using a commercially available electroless nickel plating bath and electroless gold plating bath, and then, the presence or absence of resist stripping and the presence or absence of plating penetration were evaluated based on tape stripping, and then, the presence or absence of resist stripping was evaluated based on tape stripping. The criterion is as follows.

O: no penetration and peeling were observed.

Delta: a small penetration was confirmed after plating, but no peeling was observed after tape peeling.

X: the plating is followed by stripping.

(discoloration resistance (reflow soldering))

For each of the test pieces of examples 2-1 to 2-14 and comparative examples 2-1 to 2-5 described above (reflectance measurement), an initial value of Y value of XYZ chromaticity system and initial values of L, a, b of chromaticity system were measured using a Minolta system color colorimeter CR-400. Thereafter, each test piece was passed through a reflow oven having a maximum temperature of 260 degrees 3 times, and each value was measured again by a color difference meter CR-400 manufactured by Minolta, and evaluated by using the change in Y value and Δe×ab. Δe×ab is obtained by calculating the difference between the initial value and the accelerated degradation in the l×a×b color system, and therefore, a larger value indicates a larger color change. The equation Δe×ab is as follows.

ΔE*ab＝((L*2-L*1) ² +(a*2-a*1) ² +(b*2-b*1) ² ) ^0.5

(wherein, L1, a 1, b 1 respectively represent initial values of L, a, b, L2, a 2, b 2 respectively represent values of L, a, b after 3 reflow processes.)

The evaluation criteria are as follows.

◎：ΔE*ab<1.0

〇：1.0≤ΔE*ab<1.5

△：1.5≤ΔE*ab<3.0

×：3.0≤ΔE*ab

As is clear from the evaluation results shown in tables 3 and 4, the photosensitive laminated structures of examples 2-1 to 2-14 have high reflectance, good resolution, and excellent scratch resistance.

Example 3

< preparation of resin composition >

The materials described in table 5 were mixed according to the formulations described in table 5, and after premixing in a mixer, each resin composition was prepared by kneading with a three-roll mill. The values in the table are not particularly limited as long as they are parts by mass and are other than the organic solvent.

TABLE 5

*3-1: the resin solution of the carboxyl group-containing resin obtained in Synthesis example 1

*3-2: the resin solution of the carboxyl group-containing resin obtained in Synthesis example 2

*3-3: dipentaerythritol hexaacrylate (manufactured by Japanese chemical Co., ltd.)

*3-4: bisphenol A type novolak epoxy resin (DIC Co., ltd.)

*3-5: tetramethyl biphenol epoxy resin (Mitsubishi chemical Co., ltd.)

*3-6: oxime ester photopolymerization initiator (BASF Co., ltd.)

*3-7: alumina (manufactured by Nippon light metals Co., ltd.) (average particle diameter 0.5 μm, thermal conductivity 30W/m.K)

*3-8: barium sulfate (made by Sakai chemical Co., ltd.) (average particle diameter 0.3 μm, thermal conductivity 1.5W/m.K)

< preparation of Dry film having photosensitive laminate resin Structure >

Using the resin compositions 3-1 to 3-9 obtained as described above, photosensitive laminated resin structures were produced as follows. First, the composition of table 5 corresponding to the protective layer (B) shown in table 6 was applied to a polyethylene terephthalate (PET) support film having a thickness of 35 μm and dried to prepare a dry film having the protective layer (B). Then, the composition of table 5 corresponding to the filler-filled layer (a) (hereinafter referred to as the heat dissipation layer (a)) shown in table 6 was applied onto the protective layer (B) and dried to prepare a dry film having the heat dissipation layer (a). Then, a biaxially oriented polypropylene (OPP) film 15 μm thick was laminated on the surface of the heat dissipation layer (a), and a dry film composed of 4 layers of a support film (PET film), a protective layer (B), the heat dissipation layer (a), and a protective film (OPP film) was produced.

TABLE 6

The photosensitive laminated resin structures were evaluated as follows using the dry films of examples 3-1 to 3-8 and comparative examples 3 to 1-3 prepared as described above.

(optimal exposure)

A single-sided printed circuit board having a copper thickness of 15 μm and a circuit formed thereon was prepared, and pretreatment was performed using MEC co., ltd. The protective films in contact with the heat dissipation layer (a) in the dry films of examples 3-1 to 3-8 and comparative examples 3-1 to 3-3 were peeled off, and the heat dissipation layer (a) was bonded to the substrate by using a vacuum laminator so as to form a photosensitive laminated resin structure on the substrate. The substrate was exposed to light using a Stuffer 41-stage exposure meter (Kodak No. 2) using an exposure apparatus equipped with a high-pressure mercury lamp (short arc lamp), heated at 100℃for 30 minutes after exposure, and then the PET film in contact with the protective layer (B) was peeled off, and developed for 60 seconds (30℃0.2MPa, 1wt% Na) ₂ CO ₃ Aqueous solution), the pattern of the Stuffer41 level step exposure meter remaining at the time of 5 levels was used as the optimum exposure amount.

(measurement of thermal conductivity)

A50 μm Teflon sheet was adhered to one surface of a corrosion substrate having a thickness of 0.8mm, and then the protective films of the dry films of examples 3-1 to 3-8 and comparative examples 3 to 1-3, which were in contact with the heat dissipation layer (A), were peeled off, and bonded by using a vacuum laminator so that the heat dissipation layer (A) was in contact with the Teflon sheet. Thereafter, the dry films were laminated, and a full-face exposure was performed at each optimum exposure amount using an exposure apparatus equipped with a high-pressure mercury lamp, and heating was performed at 100 ℃ for 30 minutes. Then, the PET film in contact with the protective layer (B) was peeled off, developed for 60 seconds with a 1wt% sodium carbonate aqueous solution at 30℃under a jet pressure of 0.2MPa, and heated and cured at 150℃for 60 minutes. Thereafter, the cured dry film (cured film) was peeled off from the Teflon sheet to obtain a test piece for measuring thermal conductivity. The thermal conductivity of each test piece obtained was measured by a "periodic heating thermal diffusivity measuring device FTC-RT", manufactured by Advance Riko Co., ltd.

The thermal conductivity of each test piece is shown in table 6.

(evaluation of resolution (evaluation of minimum opening diameter))

In the production of the test pieces of examples 3-1 to 3-8 and comparative examples 3 to 1 to 3-3 described above (measurement of thermal conductivity), the test pieces for resolution evaluation were obtained by the same method as the production of the test pieces described above (measurement of thermal conductivity) except that the exposure was performed with a negative mask having a negative pattern of via hole opening diameters of 500 μm, 300 μm, 150 μm, 100 μm, 80 μm, 60 μm as a negative mask for resolution evaluation, and the pattern exposure was performed at the respective optimum exposure amounts. For each of the obtained test pieces, the pattern opening was observed using SEM, and the minimum opening diameter was evaluated.

(scratch resistance)

On each of the test pieces described above (measurement of thermal conductivity), a brass cylinder having a diameter of 1cm and a height of 2cm and a weight of 10g were placed in this order and fixed, and the cylinder on which the weight was placed was slid over the test piece at a speed of 1 cm/sec for 5cm to visually confirm whether or not a black scratch was generated on the test piece.

The criterion is as follows.

O: no scratch

X: scratch is generated

(breakdown voltage)

The dry films of examples 3-1 to 3-8 and comparative examples 3 to 1-3 were laminated on one surface of a copper-clad substrate having a thickness of 0.8mm using a vacuum laminator so that the heat-dissipating layer (A) was in contact with the copper-clad substrate. Thereafter, the dry films were subjected to surface-mount exposure at the optimum exposure levels using an exposure apparatus equipped with a high-pressure mercury lamp, and heated at 100℃for 30 minutes. Then, the PET film in contact with the protective layer (B) was peeled off, developed for 60 seconds with a 1wt% sodium carbonate aqueous solution at 30℃under a jet pressure of 0.2MPa, heated and cured at 150℃for 60 minutes, and a test piece for evaluation of breakdown voltage was obtained. Then, for each of the obtained test pieces, a voltage was boosted at 0.5 kV/sec with respect to the thickness direction (Z axis direction) of the cured film using a withstand voltage tester TOS5051A manufactured by chrysanthemi-water electronics industry co.

As is clear from the evaluation results shown in Table 6, the photosensitive laminated structures of examples 3-1 to 3-8 were high in heat dissipation, good in resolution, and excellent in scratch resistance.

Description of the reference numerals

1. Printed circuit board with improved heat dissipation

2. Conductor circuit

3. Filler filling layer (A)

4. Protective layer (B)

5. Mask for mask

10 Dry film

11 support film

12 protective layer (B)

13 Filler filling layer (A)

14 protective film

Claims

1. A photosensitive laminated resin structure is characterized by comprising: a filler-filled layer (A) and a protective layer (B),

the filler-filled layer (A) is substantially free of photopolymerization initiator, and the filler content is 10 to 80 mass% of all components except the organic solvent,

the filler content of the protective layer (B) is 0 to 25 mass% relative to the filler content of the filler-filled layer (A).

2. The photosensitive laminated resin structure according to claim 1, wherein the filler-filled layer (a) has a layer thickness greater than that of the protective layer (B).

3. The photosensitive laminated resin structure according to claim 1 or 2, wherein the filler is silica.

4. The photosensitive laminated resin structure according to claim 1 or 2, wherein the filler is titanium oxide,

5. The photosensitive laminated resin structure according to claim 1 or 2, wherein,

the filler is a heat dissipation filler with heat conductivity higher than 10W/m.K,

6. A dry film, characterized in that at least one side of the photosensitive laminated resin structure according to claim 1 to 5 is supported or protected by a film.

7. A cured product comprising the photosensitive laminated resin structure according to claim 1 to 5 or the dry film according to claim 6.

8. An electronic component comprising the cured product according to claim 7.