CN114787712A

CN114787712A - Photosensitive laminate, method for producing photosensitive laminate, and method for producing circuit board

Info

Publication number: CN114787712A
Application number: CN202080085647.2A
Authority: CN
Inventors: 石想勋
Original assignee: Kolon Industries Inc
Current assignee: Kolon Industries Inc
Priority date: 2019-12-31
Filing date: 2020-11-27
Publication date: 2022-07-22
Also published as: CN114846404A; TWI780533B; WO2021137444A1; JP2023508388A; JP7535585B2; TW202129417A; TW202128788A; JP2023508163A; JP7526267B2; WO2021137443A1; TWI778466B

Abstract

The present disclosure relates to a photosensitive laminate and a method of preparing the same, the photosensitive laminate comprising: a support substrate; and a photosensitive resin layer formed on the support substrate, wherein 5/mm is present in the photosensitive resin layer²The following bubbles having a diameter of less than 1 μm.

Description

Photosensitive laminate, method for producing photosensitive laminate, and method for producing circuit board

Technical Field

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of korean patent application No. 10-2019-.

The present disclosure relates to a photosensitive laminate, a method of manufacturing the photosensitive laminate, and a method of manufacturing a circuit board.

Background

The photosensitive resin composition is used in the form of a dry film photoresist (DFR), a liquid photoresist ink, etc., which are used in a Printed Circuit Board (PCB) or a lead frame.

In recent years, with the trend of semiconductor devices becoming light, thin, short, and small or multi-level packaging, high density is required for circuit boards, and processes such as ultra-high pressure mercury lamps or direct exposure to laser light are applied, or manufacturing processes of circuit boards using photosensitive laminates including a support film and a photosensitive resin layer are widely employed.

Therefore, there is a continuing need to develop methods and processes that achieve high density and sensitivity and enable the formation of finer wiring while ensuring higher reliability.

[ Prior art documents ]

[ patent document ]

(patent document 1) Japanese patent publication No.2006-106287 (published: 2006.04.20)

Disclosure of Invention

[ problem ] to

In the present disclosure, a photosensitive laminate capable of forming a high-density circuit by ensuring high reliability in a developing process while reducing defects in forming fine wiring is provided.

In the present disclosure, there is also provided a method of preparing the above photosensitive laminate.

In the present disclosure, there is also provided a method of manufacturing a circuit board using the above photosensitive laminate.

[ solution ]

In the present disclosure, there is provided a photosensitive laminate comprising: a support substrate; and a photosensitive resin layer formed on the support substrate, wherein 5/mm is present in the photosensitive resin layer²The following bubbles having a diameter of less than 1 μm.

In the present disclosure, there is also provided a method for manufacturing a circuit board using the above photosensitive laminate.

Hereinafter, the photosensitive laminate, the method of manufacturing the photosensitive laminate, and the method of manufacturing the circuit board according to the embodiments of the present invention will be described in more detail.

In the present disclosure, the weight average molecular weight refers to a weight average molecular weight in terms of polystyrene measured by GPC. In measuring the polystyrene-reduced weight average molecular weight measured by GPC, a known analyzing apparatus, detector (such as a refractive index detector) and analytical column can be used, and the temperature conditions, solvent and flow rate that are generally applied can be applied.

As a specific example of the measurement conditions, an alkali-developable binder resin was dissolved in tetrahydrofuran at a concentration of 1.0 (w/w)% in THF (about 0.5 (w/w)%, based on the solid content), and then filtered using a syringe filter with a pore size of 0.45 μm, followed by injecting 20 μ l into GPC. The mobile phase of the GPC was Tetrahydrofuran (THF) and flowed at a flow rate of 1.0 mL/min. Using a column in which 1 Agilent PLgel5 μm Guard (7.5X 50mm) and 2 Agilent PLgel5 μm Mixed D (7.5X 300mm) were connected in series, an Agilent 1260Infinity II System, RI Detector was used for the measurement at 40 ℃.

Polystyrene standards (STD a, STD B, STD C, STD D) obtained by dissolving polystyrenes having different molecular weights in tetrahydrofuran at a concentration of 0.1 (w/w)% were filtered through a syringe filter having a pore size of 0.45 μm and then injected into GPC, and a calibration curve formed therefrom was used to obtain the weight average molecular weight (Mw) of the alkali-developable binder resin.

STD A(Mp):791,000/27,810/945

STD B(Mp):282,000/10,700/580

STD C(Mp):126,000/4,430/370

STD D(Mp):51,200/1,920/162

The term "(photo) cured product" or "(photo) cured" includes not only the case where a component having a curable or crosslinkable unsaturated group in its chemical structure is completely cured, crosslinked or polymerized, but also the case where such a component is partially cured, crosslinked or polymerized.

According to an embodiment of the present disclosure, there is provided a photosensitive laminate including: a support substrate; and a photosensitive resin layer comprising a photopolymerizable compound comprising a polyfunctional (meth) acrylate compound having three or more functionalities and an alkali developable binder resin, wherein 5/mm is present in the photosensitive resin layer²The following bubbles having a diameter of less than 1 μm.

The present inventors have newly developed a photosensitive laminate comprising a photosensitive resin composition in which 5 sheets/mm are present²The following photosensitive resin layer having bubbles with a diameter of less than 1 μm. They have experimentally confirmed the use of such a photosensitive layerThe stamp material enables high sensitivity to exposure during the production of a circuit board and improves reliability during development, thereby ensuring high reliability, achieving high density and high sensitivity, and enabling the formation of finer wiring.

The present inventors have conducted continuous research and development to remove a trace amount of fine bubbles or fine byproducts that may occur due to various reasons during the preparation process, and formed a photosensitive resin layer using a resin composition simultaneously including a mixed solvent including a high boiling point solvent having a boiling point of 115 ℃ or more and a low boiling point solvent having a boiling point of 100 ℃ or less, an alkali-developable binder resin, a photopolymerizable compound, and a photoinitiator such that 5/mm exists in the photosensitive resin layer²Below or 3/mm²The following bubbles having a diameter of less than 1 μm.

In addition, in the production method of the photosensitive laminate, in addition to using a mixed solvent containing a high boiling point solvent having a boiling point of 115 ℃ or more and a low boiling point solvent having a boiling point of 100 ℃ or less, by adjusting the drying speed and/or the drying temperature, the amount of fine bubbles formed in the photosensitive resin layer may be greatly reduced or may be substantially absent.

Meanwhile, in the photosensitive resin layer, there may be 5/mm²Below or 3/mm²Bubbles wherein the diameter of the bubbles is less than 1 μm. In particular, on the opposite surface of the interface between the support substrate and the photosensitive resin layer, or on the outer surface of the photosensitive resin layer, bubbles having a diameter of less than 1 μm may be present in trace amounts or may be substantially absent.

More specifically, there may be 3/mm in the photosensitive resin layer of 50% of the total thickness from the opposite surface of the interface between the support substrate and the photosensitive resin layer²The following bubbles having a diameter of less than 1 μm.

Since the bubbles having a diameter of less than 1 μm are present in trace or substantially absent on the opposite surface of the interface between the support substrate and the photosensitive resin layer or on the outer surface of the photosensitive resin layer, reliability is improved during development, enabling formation of a high-density circuit and defects in fine wiring formation can be reduced. Therefore, when the photosensitive laminate is used, high sensitivity to exposure can be achieved, and the manufacturing yield of a high-density printed circuit board can be improved.

Further, in the photosensitive laminate, not only may bubbles having a diameter of less than 1 μm be present in trace amounts or may be substantially absent, but also bubbles having a diameter of 1 μm to 5 μm may be absent.

In this way, when a photosensitive laminate in which a small amount of bubbles having a diameter of less than 1 μm are present in the photosensitive resin layer is used in the production of a circuit board, high density and high sensitivity can be achieved while ensuring high reliability, and finer wiring can be formed.

More specifically, even when the photosensitive resin layer is exposed to ultraviolet rays and developed with an alkali solution, defects do not occur or a very small number of defects may occur in the entire area. In particular, there is substantially no defect on the upper surface of the photosensitive resin layer after development, and there may be a minute defect on the lower surface or inside of the photosensitive resin layer.

Specifically, after exposing the photosensitive resin layer to ultraviolet rays, followed by development with an alkali solution, 3 pieces/mm may be observed²The following defects or 1/mm²A defect having a cross-sectional diameter of 0.3 μm to 4 μm, or having a cross-sectional diameter of 0.5 μm or more and 3 μm or less, or a defect may be substantially absent. The cross-sectional diameter of the defect may be defined as the largest diameter among diameters of defects defined in a cross-section in one direction on the photosensitive resin layer.

The conditions of exposure and development are not particularly limited. For example, the exposure may be performed for 1 minute to 60 minutes with an amount of energy such that the number of remaining stages is 15 stages, wherein light irradiated to the photosensitive laminate is measured in a range of 340nm to 420nm using a step table (step table) manufactured by Stouffer Graphic Arts Equipment. In addition, the development can be carried out, for example, by using an aqueous alkali solution (e.g., Na) having a concentration of 0.1 to 3.0 wt%₂CO₃) The spraying method (3) or the like.

Further, when the photosensitive laminate is used, higher density and sensitivity can be achieved while using less energy. More specifically, the amount of energy for making the number of remaining stages 15 stages may be 300mJ/cm²Below, or 100mJ/cm²Hereinafter, light irradiated to the photosensitive laminate was measured in the range of 340nm to 420nm using a 41-step exposure table (step table) manufactured by Stouffer Graphic Arts Equipment. The resolution after development may be 15 μm or less or 10 μm or less.

The thickness of the support substrate and the thickness of the photosensitive resin layer in the photosensitive laminate are not particularly limited, but the thickness of the support substrate may be 1 μm to 100 μm, or 5 μm to 50 μm, and the thickness of the photosensitive resin layer may be 1 μm to 100 μm, or 5 μm to 50 μm.

Meanwhile, the photosensitive laminate is characterized in that the photosensitive resin layer contains 5/mm²The structural features of the following bubbles having a diameter of less than 1 μm may be attributable to the above-described production method or may be attributable to the features of the photosensitive resin layer.

Specifically, the photosensitive resin layer may include an alkali-developable binder resin. The alkali developable binder may contain at least one carboxyl group in the molecule and may react with an alkali during development.

Specific examples of the alkali-developable binder are not limited, but the alkali-developable binder may be a polymer or copolymer including at least one repeating unit selected from the group consisting of a repeating unit represented by the following chemical formula 4, a repeating unit represented by the following chemical formula 5, and a repeating unit represented by the following chemical formula 6.

[ chemical formula 4]

In chemical formula 4, R₃Is hydrogen or C1 to C10 alkyl,

[ chemical formula 5]

In chemical formula 5, R₄Is hydrogen or C1 to C10 alkyl, R₅Is a C1 to C10 alkyl group,

[ chemical formula 6]

In chemical formula 6, Ar is a C6 to C20 aryl group.

In chemical formulas 4 to 6, R₃And R₄Are identical to or different from one another and are each independently hydrogen or C1 to C10 alkyl, R₅Is a C1 to C10 alkyl group, and Ar is a C6 to C20 aryl group.

R₅Is a C1 to C10 alkyl group, and a specific example of the C1 to C10 alkyl group may be a methyl group. Ar is a C6 to C20 aryl group, and a specific example of the C6 to C20 aryl group may be a phenyl group.

The repeating unit represented by chemical formula 4 may be a repeating unit derived from a monomer represented by chemical formula 4-1 below.

[ chemical formula 4-1]

In chemical formula 4-1, R₃Is hydrogen or C1 to C10 alkyl. In chemical formula 4-1, for R₃The description of (b) is the same as that described above in chemical formula 4. Specific examples of the monomer represented by chemical formula 4-1 may include Acrylic Acid (AA) and methacrylic acid (MAA).

The repeating unit represented by chemical formula 5 may be a repeating unit derived from a monomer represented by chemical formula 5-1 below.

[ chemical formula 5-1]

In chemical formula 5-1, R₄Is hydrogen or C1 to C10 alkyl, R₅Is a C1 to C10 alkyl group. In chemical formula 3-1, for R₄And R₅The description of (b) is the same as the above description in chemical formula 3. Specific examples of the monomer represented by chemical formula 3-1 may include Methyl Methacrylate (MMA) and Butyl Acrylate (BA).

The repeating unit represented by chemical formula 6 may be a repeating unit derived from a monomer represented by chemical formula 6-1 below.

[ chemical formula 6-1]

In chemical formula 6-1, Ar is a C6 to C20 aryl group. In chemical formula 6-1, the description of Ar is the same as that described above in chemical formula 4. Specific examples of the monomer represented by chemical formula 6-1 may include Styrene (SM)

Meanwhile, the alkali developable binder resin may be used as a substrate of the photosensitive resin layer and thus should have a minimum molecular weight, for example, a weight average molecular weight of 20,000g/mol to 300,000g/mol, or 30,000g/mol to 150,000 g/mol.

In addition, the alkali-developable binder resin should have heat resistance of a certain level or more and thus may have a glass transition temperature of 20 ℃ or more and 150 ℃ or less.

Further, the alkali-developable binder resin may have an acid value in the range of 100mgKOH/g to 300mgKOH/g in consideration of developability of the photosensitive resin layer.

Meanwhile, the alkali-developable binder resin may contain two or more alkali-developable binders having different types or different properties. Specifically, the alkali-developable binder resin may include a first alkali-developable binder resin and a second alkali-developable binder resin.

The first and second alkali-developable binder resins may have a weight average molecular weight of 30000g/mol or more and 150000g/mol or less and a glass transition temperature of 20 ℃ or more and 150 ℃ or less, and each may have a different weight average molecular weight, glass transition temperature, or acid value.

For example, the first alkali-developable binder resin may have an acid value of 140mgKOH/g or more and 160mgKOH/g or less. Further, the second alkali-developable binder resin may have an acid value of 160mgKOH/g or more and 200mgKOH/g or less.

Further, the glass transition temperature ratio of the first alkali developable binder resin to the second alkali developable binder resin may be 1:1.5 or greater than 1.5 and 1:5 or less than 5, 1:1.5 or greater than 1.5 and 1:3 or less than 3, 1:1.5 or greater than 1.5 and 1:2 or less than 2, 1:1.5 or greater than 1.5 and 1:1.8 or less than 1.8, 1:1.5 or greater than 1.5 and 1:75 or less than 75, or 1:1.6 or greater than 1.6 and 1:7 or less than 7.

Further, the ratio of the acid numbers of the first alkali-developable binder resin to the second alkali-developable binder resin may be 1:1.01 or greater than 1.01 and 1:1.5 or less than 1.5, 1:1.1 or greater than 1.1 and 1:1.5 or less than 1.5, 1:1.25 or greater than 1.25 and 1:1.5 or less than 1.5, 1:1.4 or greater than 1.4 and 1:1.5 or less than 1.5.

Meanwhile, the photosensitive resin layer may include a crosslinked copolymer between an alkali developable binder resin and a photopolymerizable compound including a (meth) acrylate monomer or oligomer.

The photopolymerizable compound including the (meth) acrylate monomer or oligomer may be used as a crosslinking agent to improve the mechanical strength of the photosensitive resin layer, or may function to improve resistance to a developer and impart flexibility to a cured film.

The content of the photopolymerizable compound including the (meth) acrylate monomer or oligomer may be adjusted depending on the specific use or characteristics of the photosensitive resin layer. For example, the photopolymerizable compound including the (meth) acrylate monomer or oligomer may be included in an amount of 1 to 80 parts by weight, based on 100 parts by weight of the alkali-developable binder resin.

The photopolymerizable compound may be a monofunctional or multifunctional (meth) acrylate monomer or oligomer. The photopolymerizable compound may be a well-known monofunctional or polyfunctional (meth) acrylate monomer or oligomer, but in order for the photosensitive resin layer to satisfy the above characteristics, the photopolymerizable compound may contain a polyfunctional (meth) acrylate compound having three or more functionalities.

That is, as described in the production method described later, the photosensitive laminate of the present embodiment uses two or more solvents having different boiling points. Therefore, depending on the photopolymerizable compound to be used, fine bubbles may be present in the photosensitive resin layer in a trace amount, or may be substantially absent.

Specifically, the multifunctional (meth) acrylate compound having three or more functionalities may have a structure in which three or more C1 to C10 alkyleneoxy groups and three or more (meth) acrylate functional groups are bonded to the C1 to C20 central group.

Due to the structure of such a polyfunctional (meth) acrylate compound having three or more functionalities, a small amount of bubbles having a diameter of 1 μm or less may be present in the photosensitive resin layer, thereby reducing defects in the formation of fine wiring. In addition, by ensuring high reliability in the development process, a photosensitive laminate capable of forming a high-density circuit can be provided.

More specifically, the multifunctional (meth) acrylate compound having three or more functionalities may include a compound of the following chemical formula 1:

[ chemical formula 1]

In chemical formula 1, R₄Is hydrogen or C1 to C10 alkyl, R₅Is C1 to C10 alkylene, R₆Is a p-valent functional group having a central group of C1 to C20, n2 is an integer of 1 to 20, and p is R₆The number of the functional groups substituted, and is an integer of 3 to 10.

More specific examples of the compound of chemical formula 1 may include compounds of the following chemical formula 1-1.

[ chemical formula 1-1]

In the chemical formula 1-1,

R₆' is a trivalent functional group from C1 to C10,

R₇to R₉Each independently a C1 to C10 alkylene,

R₁₀to R₁₂Each independently hydrogen or C1 to C10 alkyl, and

n3 to n5 are each independently an integer of 1 to 3.

Meanwhile, the photopolymerizable compound may further include a monofunctional (meth) acrylate compound or a difunctional (meth) acrylate compound.

The monofunctional (meth) acrylate compound may include a (meth) acrylate containing a C1 to C10 alkyleneoxy group.

Specifically, the monofunctional (meth) acrylate compound may include a monofunctional (meth) acrylate compound represented by the following chemical formula 2.

[ chemical formula 2]

In chemical formula 2, R₁Is hydrogen or C1 to C10 alkyl, R₂Is C1 to C10 alkylene, R₃Is a C1 to C10 alkyl group, and n1 is an integer of 1 to 20.

The photopolymerizable compound may together include the above monofunctional (meth) acrylate compound and a polyfunctional (meth) acrylate compound having three or more functionalities. Specifically, the photopolymerizable compound may include: a monofunctional (meth) acrylate compound including a (meth) acrylate containing a C1 to C10 alkyleneoxy group; and a multifunctional (meth) acrylate compound having three or more functionalities, the multifunctional (meth) acrylate compound having a structure in which three or more C1 to C10 alkyleneoxy groups and three or more (meth) acrylate functional groups are bonded to a C1 to C20 central group.

The content of the monofunctional (meth) acrylate compound and the polyfunctional (meth) acrylate compound having three or more functionalities contained in the photopolymerizable compound may be adjusted in consideration of the characteristics of the pressure-sensitive resin layer and the pressure-sensitive laminate.

For example, the photopolymerizable compound may include 110 parts by weight or more and 500 parts by weight or less of the multifunctional (meth) acrylate compound having three or more functionalities, based on 100 parts by weight of the monofunctional (meth) acrylate compound.

Further, the photopolymerizable compound may include 500 parts by weight or more and 1000 parts by weight or less of the bifunctional (meth) acrylate compound based on 100 parts by weight of the polyfunctional (meth) acrylate compound having three or more functionalities.

Meanwhile, the photopolymerizable compound may further include a monofunctional or polyfunctional (meth) acrylate compound different from the above monofunctional (meth) acrylate compound and the above polyfunctional (meth) acrylate compound having three or more functionalities. In this case, the monofunctional or polyfunctional (meth) acrylate compound that may be used excludes the polyfunctional (meth) acrylate compound of chemical formula 1 having three or more functionalities and the monofunctional (meth) acrylate compound of chemical formula 2.

Examples of the photopolymerizable compound that may be additionally used are not limited, but may include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, propylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, butanediol dimethacrylate, neopentyl glycol dimethacrylate, 1, 6-hexanediol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, glycerol dimethacrylate, pentaerythritol trimethacrylate, dipentaerythritol pentamethacrylate, 2-bis (4-methacryloxydiethoxyphenyl) propane, 2-bis (4-methacryloxypolyethoxyphenyl) propane, propylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, butylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1, 6-hexanediol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, glycerol dimethacrylate, pentaerythritol trimethacrylate, dipentaerythritol trimethacrylate, 2-bis (4-methacryloxypolyethoxyphenyl) propane, 2-bis (4-methacryloxypolyethoxyphenyl) propane, propylene glycol dimethacrylate, ethylene glycol dimethacrylate, and the like, 2-hydroxy-3-methacryloxypropyl methacrylate, ethylene glycol diglycidyl ether dimethacrylate, diethylene glycol diglycidyl ether dimethacrylate, phthalic acid diglycidyl ester dimethacrylate, glycerol polyglycidyl ether polymethacrylate, and polyfunctional (meth) acrylates containing urethane groups.

Meanwhile, the support substrate may function as a support of the photosensitive laminate, and may facilitate handling of the photosensitive resin layer having adhesive strength during exposure.

Various plastic films may be used for the base film, and for example, at least one plastic film selected from an acrylic film, a polyethylene terephthalate (PET) film, a triacetyl cellulose (TAC) film, a Polynorbornene (PNB) film, a cycloolefin polymer (COP) film, and a Polycarbonate (PC) film may be used.

Meanwhile, the photosensitive laminate may further include a protective film formed to face the support substrate with the photosensitive resin layer as a center. The protective film prevents damage to the resist during processing, and serves as a protective cover for protecting the photosensitive resin layer from foreign matter such as dust, and may be laminated on the other surface of the photosensitive resin layer on which the base film is not formed.

The protective film functions to protect the photosensitive resin layer from the outside, and requires appropriate peelability and adhesiveness so that the protective film is easily peeled off when the dry film photoresist is applied for post-treatment and is not peeled off when stored and distributed.

Various plastic films may be used for the protective film, and for example, at least one plastic film selected from an acrylic film, a Polyethylene (PE) film, a polyethylene terephthalate (PET) film, a triacetyl cellulose (TAC) film, a Polynorbornene (PNB) film, a Cyclic Olefin Polymer (COP) film, and a Polycarbonate (PC) film may be used. Although the thickness of the protective film is not particularly limited, it may be freely adjusted within a range of 0.01 μm to 100 μm, for example.

According to another embodiment of the present disclosure, there is provided a method of preparing the photosensitive laminate, including the steps of: coating a resin composition on a supporting substrate, followed by drying, the resin composition comprising: a mixed solvent containing a high-boiling point solvent having a boiling point of 115 ℃ or higher and a low-boiling point solvent having a boiling point of 100 ℃ or lower; a photopolymerizable compound comprising a multifunctional (meth) acrylate compound having three or more functionalities; an alkali developable binder resin; and a photo-initiator, wherein the photo-initiator is,

wherein the mixed solvent contains a high boiling point solvent having a boiling point of 115 ℃ or higher and a low boiling point solvent having a boiling point of 100 ℃ or lower in a weight ratio of 1:2 to 1: 18.

The photosensitive laminate material as described above in one embodiment can be provided according to the above-described production method. As described above, the photosensitive laminate includes: a support substrate; and a photosensitive resin layer including a photopolymerizable compound including a polyfunctional (meth) acrylate compound having three or more functionalities and an alkali-developable binder resin. There may be 5/mm in the photosensitive resin layer²The following bubbles having a diameter of less than 1 μm.

In the process of forming the photosensitive resin layer, bubbles having a diameter of less than 1 μm may be formed in the photosensitive resin layer due to, for example, bubbles generated during the preparation process of the photosensitive resin composition solution or the drying process of the composition solution. However, the above-mentioned method for preparing a photosensitive laminate uses a mixed solvent including a high boiling point solvent having a boiling point of 115 ℃ or more and a low boiling point solvent having a boiling point of 100 ℃ or less to delay the evaporation time of the solution of the photosensitive resin composition, thereby preventing air bubbles from being trapped in the resin layer, and thus, there may be 5/mm in the photosensitive resin layer²The following bubbles having a diameter of less than 1 μm.

More specifically, there may be 5/mm in the photosensitive resin layer²Below or 3/mm²The following are providedWherein the diameter of the bubble is less than 1 μm.

Further, 3/mm may exist in the photosensitive resin layer of 50% of the total thickness from the opposite surface of the interface between the support substrate and the photosensitive resin layer²The following bubbles having a diameter of less than 1 μm.

Since the bubbles having a diameter of less than 1 μm are present in trace or substantially absent on the opposite surface of the interface between the support substrate and the photosensitive resin layer or on the outer surface of the photosensitive resin layer, reliability is improved during development, enabling formation of a high-density circuit and defects in fine wiring formation can be reduced. Therefore, when the photosensitive laminate is used, high sensitivity to exposure light can be achieved, and the manufacturing yield of a high-density printed circuit board can be improved.

As described above, the high boiling point solvent having a boiling point of 115 ℃ or more may function to delay the evaporation time of the liquid component of the photosensitive resin composition so that air bubbles are not trapped in the resin layer. Therefore, there may be 5/mm in the photosensitive resin layer²The following bubbles having a diameter of less than 1 μm.

The mixed solvent may contain a predetermined amount or more of a high boiling point solvent having a boiling point of 115 ℃ or more, for example, 3 parts by weight or more, 5 parts by weight or more, 3 to 50 parts by weight or 5 to 40 parts by weight of a high boiling point solvent having a boiling point of 115 ℃ or more, based on 100 parts by weight of the mixed solvent.

When a low boiling point solvent having a boiling point of 100 ℃ or less is used together with a high boiling point solvent having a boiling point of 115 ℃ or more, the solubility of the photosensitive resin composition can be improved.

The mixed solvent may contain a higher content of a low boiling point solvent having a boiling point of 100 ℃ or less than a high boiling point solvent having a boiling point of 115 ℃ or more.

More specifically, the mixed solvent contains a high boiling point solvent having a boiling point of 115 ℃ or higher and a low boiling point solvent having a boiling point of 100 ℃ or lower in a weight ratio of 1:2 to 1:18, or 1:3 to 1: 15. When the high boiling point solvent having a boiling point of 115 ℃ or higher and the low boiling point solvent having a boiling point of 100 ℃ or lower are contained in the above weight ratio, the solubility of the photosensitive resin composition can be improved.

Examples of the high boiling point solvent having a boiling point of 115 ℃ or higher may include butanol, dimethylformamide, N-methyl-2-pyrrolidone, γ -butyrolactone, butyl carbitol, butyl cellosolve, methyl cellosolve, butyl acetate, diethylene glycol methyl ethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propylene glycol methyl ether propionate, dipropylene glycol dimethyl ether, cyclohexanone, Propylene Glycol Monomethyl Ether Acetate (PGMEA), and mixed solvents thereof.

Examples of the low boiling point solvent having a boiling point of 100 ℃ or less may include methyl ethyl ketone, methanol, ethanol, acetone, tetrahydrofuran, isopropanol, and a mixed solvent thereof.

In the resin composition including the mixed solvent including the high boiling point solvent having a boiling point of 115 ℃ or more and the low boiling point solvent having a boiling point of 100 ℃ or less, the alkali developable binder resin, and the photoinitiator, the solid content may be controlled in consideration of a specific use or application field, and for example, the resin composition may include 10 wt% to 99 wt% of the mixed solvent.

Meanwhile, a method or apparatus that may be used in the step of coating the resin composition on the support substrate and then drying is not particularly limited. For example, the resin composition may be coated on a conventional base film (such as polyethylene terephthalate) using a conventional coating method, and then dried to prepare a dry film.

The method of coating the resin composition is not particularly limited, and for example, a method such as a bar coating method or the like can be used.

In the production method of the photosensitive laminate, in addition to using a mixed solvent containing a high boiling point solvent having a boiling point of 115 ℃ or more and a low boiling point solvent having a boiling point of 100 ℃ or less, by adjusting the drying speed and/or the drying temperature, the amount of fine bubbles formed in the photosensitive resin layer may be greatly reduced or may be substantially absent.

More specifically, the step of drying the coated resin composition may be performed at a temperature of 50 ℃ to 100 ℃, 60 ℃ to 90 ℃, or 70 ℃ to 85 ℃ by heating means such as a hot air oven, a hot plate, a hot air circulating furnace, or an infrared furnace.

The drying time may vary depending on the drying temperature, and may be, for example, 30 seconds to 20 minutes, more specifically, 1 minute to 10 minutes, or 3 minutes to 7 minutes.

The description of the alkali-developable binder resin contained in the resin composition includes the description described in the photosensitive laminate of the above embodiment.

The alkali-developable binder resin may have a weight average molecular weight of 20,000 to 300,000g/mol, or 30,000 to 150,000g/mol, and a glass transition temperature of 20 ℃ or more and 150 ℃ or less.

The alkali-developable binder resin may have an acid value in the range of 100mgKOH/g to 300 mgKOH/g.

The resin composition may further include a photopolymerizable compound including a (meth) acrylate monomer or oligomer and the alkali developable binder resin.

The resin composition may include 1 to 80 parts by weight of a photopolymerizable compound including a (meth) acrylate monomer or oligomer based on 100 parts by weight of the alkali developable binder resin.

The description of the photopolymerizable compound includes the description described in the photosensitive laminate of the above embodiment.

In the method of producing the photosensitive laminate of the embodiment, two or more solvents having different boiling points are used. Therefore, depending on the photopolymerizable compound to be used, fine bubbles may be present in trace amounts in the photosensitive resin layer, or may be substantially absent.

Specifically, the multifunctional (meth) acrylate compound having three or more functionalities may have a structure in which three or more C1 to C10 alkyleneoxy groups and three or more (meth) acrylate functional groups are bonded to a C1 to C20 central group.

[ chemical formula 1]

In chemical formula 1, R₄Is hydrogen or C1 to C10 alkyl, R₅Is C1 to C10 alkylene, R₆Is a p-valent functional group having a central group of from C1 to C20, n2 is an integer of from 1 to 20, and p is R₆The number of the functional groups substituted, and is an integer of 3 to 10.

[ chemical formula 1-1]

In chemical formula 1-1, R₆' is a trivalent functional group from C1 to C10, R₇To R₉Each independently is C1 to C10 alkylene, R₁₀To R₁₂Each independently is hydrogen or a C1 to C10 alkyl group, and n3 to n5 each independently is an integer from 1 to 3.

Meanwhile, the photopolymerizable compound may further include a monofunctional (meth) acrylate compound or a bifunctional (meth) acrylate compound.

[ chemical formula 2]

The photopolymerizable compound may include the above monofunctional (meth) acrylate compound and a polyfunctional (meth) acrylate compound having three or more functionalities together. Specifically, the photopolymerizable compound may include: a monofunctional (meth) acrylate compound including a (meth) acrylate containing a C1 to C10 alkyleneoxy group; and a multifunctional (meth) acrylate compound having three or more functionalities, the multifunctional (meth) acrylate compound having a structure in which three or more C1 to C10 alkyleneoxy groups and three or more (meth) acrylate functional groups are bonded to the C1 to C20 central groups.

The photoinitiator is a material that initiates a chain reaction of photopolymerizable monomers using UV and other radiation, and plays an important role in curing the resin composition and the photosensitive resin layer of the photosensitive laminate.

Compounds that may be used as photoinitiators may include: anthraquinone derivatives such as 2-methylanthraquinone and 2-ethylanthraquinone; and benzoin derivatives such as benzoin methyl ether, benzophenone, phenanthrenequinone, and 4,4' -bis (dimethylamino) benzophenone.

A compound selected from the following may be used as the photoinitiator, but is not limited thereto: 2,2' -bis (2-chlorophenyl) -4,4' -5,5' -tetraphenyldiimidazole, 1-hydroxycyclohexylphenylketone, 2-dimethoxy-1, 2-diphenyl-1-ethanone (2,2-dimethoxy-1,2-diphenylethan-1-one), 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1- [ 4-morpholinophenyl ] -1-butanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, 2-dimethylbenzoyldiphenylphosphine oxide, 2-dimethyldiphenylphosphine oxide, 2-methyl-1-propanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and mixtures thereof, 1- [4- (2-hydroxymethoxy) phenyl ] -2-hydroxy-2-methyl-1-propanone, 2, 4-diethylthioxanthone, 2-chlorothioxanthone, 2, 4-dimethylthioxanthone, 3-dimethyl-4-methoxybenzophenone, benzophenone, 1-chloro-4-propoxythioxanthone, 1- (4-isopropylphenyl) 2-hydroxy-2-methyl-1-propanone, 1- (4-dodecylphenyl) -2-hydroxy-2-methyl-1-propanone, 4-benzoyl-4' -methyldimethylsulphide, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, methyl 2-hydroxyiminobenzoate, methyl 2-methyl-1-propanone, methyl 4-benzoylate, methyl 2-methoxybenzoate, methyl 2-hydroxy-2-methyl-1-propanone, methyl 4-benzoylate, methyl 1-one, methyl 1-methyl-2-methyl-1-propanone, methyl-1-chloro-4-propylthioxanthone, 2-4-propylthioxanthone, and their salts, Ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-isoamyl 4-dimethylaminobenzoate, 2-diethoxyacetophenone, benzylketone dimethyl acetal, benzylketone beta-methoxydiethyl acetal, 1-phenyl-1,2-propyldioxime-o, o '- (2-carbonyl) ethoxy ether (1-phenyl-1, 2-propyldioxy-o, o' - (2-carbonyl) ethoxy ether), methyl o-benzoylbenzoate, bis [ 4-dimethylaminophenyl) ketone, 4 '-bis (diethylamino) benzophenone, 4' -dichlorobenzophenone, methyl tert-butyl acetate, methyl tert-butyl acetate, ethyl acetate, ethyl acetate, ethyl acetate, benzyl, benzoin, methoxybenzoin, ethoxybenzoin, isopropoxybenzoin, n-butoxybenzoin, isobutoxybenzoin, tert-butoxybenzoin, p-dimethylaminoacetophenone, p-tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, dibenzosuberone, alpha-dichloro-4-phenoxyacetophenone and pentyl 4-dimethylaminobenzoate.

The photoinitiator may be contained in an amount of 0.1 wt% to 20 wt% or 1 wt% or more and 10 wt% or less, relative to the total weight of the resin composition, based on the solid content. When the photoinitiator is contained within the above range, sufficient sensitivity can be achieved.

If the content of the photoinitiator is too low, the exposure amount should be increased due to low light efficiency, so that the production efficiency may be greatly reduced. If the content of the photoinitiator is too high, the film may be brittle and the developer may be easily contaminated, resulting in defects such as short circuits.

In addition, the resin composition may further include other additives, if necessary. For example, dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, diallyl phthalate in the form of phthalate esters; triethylene glycol diacetate in the form of ethylene glycol esters, tetraethylene glycol diacetate; para-toluenesulfonamide, benzenesulfonamide, n-butylbenzenesulfonamide in the amide form; triphenyl phosphate, etc., can be used as a plasticizer.

To facilitate handling of the resin composition, a leuco dye or a colorant may be added. Examples of the leuco dye may include tris (4-dimethylamino-2-methylphenyl) methane, tris (4-dimethylamino-2-methylphenyl) methane and fluoran dyes. Because of the good contrast, leuco crystal violet is preferably used. In the case of including the leuco dye, the content in the photosensitive resin composition may be 0.1 wt% or more and 10 wt% or less. For contrast, 0.1 wt% or more is preferable, and for storage stability, 10 wt% or less is preferable.

The colorant may include toluenesulfonic acid monohydrate, fuchsin, phthalocyanine green, auramine base (auramine base), parafuchsin, crystal violet, methyl orange, nile blue 2B, victoria blue, malachite green, diamond green, basic blue 20, and the like. When the colorant is included, the amount thereof added may be 0.001 wt% or more and 1 wt% or less in the photosensitive resin composition. If the content is 0.001 wt% or more, there is an effect of improving the operation; if the content is less than 1 wt%, there is an effect of maintaining storage stability.

Other additives may also include thermal polymerization inhibitors, dyes, color destroying agents, adhesion promoters, and the like.

According to another embodiment of the present disclosure, there may be provided a method of manufacturing a circuit board using the photosensitive laminate of the embodiment.

The photosensitive laminate of the embodiment may be used for lamination on a copper clad laminate.

As an example of a method of manufacturing a circuit board or a Printed Circuit Board (PCB), a pretreatment process is first performed to laminate a copper clad laminate (which is a starting material of the PCB). The pre-treatment process is a drilling, deburring and scrubbing sequence in the outer process and scrubbing or acid washing in the inner process. In the scrubbing process, a scrubbing brush and a jet pumice grinding process are mainly used, and the acid washing may be performed by soft etching and sulfuric acid washing.

In order to form a circuit on the copper clad laminate which has undergone the pretreatment process, a photosensitive laminate or a dry film photoresist (hereinafter, referred to as DFR) may be generally laminated on the copper layer of the copper clad laminate. In this process, a laminator was used to laminate the photoresist layer of the DFR on the copper surface while peeling the protective film of the DFR. Typically, it can be carried out at a lamination rate of 0.5m/min to 3.5m/min, a temperature of 100 ℃ to 130 ℃, and a heated roll pressure of 10psi to 90 psi.

The printed circuit board subjected to the lamination process may be left for 15 minutes or more to stabilize the substrate, and then the photoresist of DFR may be exposed using a photomask having a desired circuit pattern formed thereon. In this process, when the photomask is irradiated with ultraviolet rays, the photoresist irradiated with ultraviolet rays can initiate polymerization in the irradiated portion by the contained photoinitiator. Initially, oxygen in the photoresist is consumed and then the activated monomer is polymerized to cause a crosslinking reaction. Thereafter, as a large amount of the monomer is consumed, the polymerization reaction may proceed, and the unexposed portion may exist in a state where the crosslinking reaction does not proceed.

Then, a developing process for removing the unexposed portion of the photoresist is performed. In the case of alkali developable DFR, 0.8 wt% to 1.2 wt% aqueous solutions of potassium carbonate and sodium carbonate may be used as the developer. In this process, the photoresist in the unexposed portion is washed away by the saponification reaction between the carboxylic acid of the binder polymer and the developer, and the cured photoresist may remain on the copper surface.

Thereafter, a circuit may be formed through different processes according to the inner layer process and the outer layer process. In the interlayer process, a circuit may be formed on a substrate through an etching and stripping process. In the outer layer process, a circuit may be formed through a plating process and a dry film trepanning process (stretching process), followed by etching and solder lift-off.

For the exposure, a conventionally known light source, more specifically, an ultra-high pressure mercury lamp or a laser direct exposure machine may be used.

[ advantageous effects ]

According to the present disclosure, it is possible to provide a photosensitive laminate capable of forming a high-density circuit by securing high reliability in a developing process while reducing defects in forming fine wiring, a method of manufacturing the photosensitive laminate, and a method of manufacturing a circuit board using the photosensitive laminate.

Drawings

Fig. 1 is a photograph of the surface and cross section of the photosensitive resin layer of example 1 confirmed by a field emission scanning electron microscope (FE-SEM, 10,000 times) using a polarization microscope.

Fig. 2 is a photograph of the surface and cross section of the photosensitive resin layer of comparative example 2 confirmed by a field emission scanning electron microscope (FE-SEM, 12,000 times) using a polarization microscope.

Fig. 3 is a photograph for confirming defects formed on the photosensitive resin layer of comparative example 2 after exposure to ultraviolet rays and development with alkali using a field emission scanning electron microscope (FE-SEM, 3000 times).

Detailed Description

The present invention will be described in more detail in the following examples. However, the following examples are provided for illustrative purposes only, and the contents of the present invention are not limited by the following examples.

Preparation of example 1

In a four-necked round-bottomed flask, a mechanical stirrer and a reflux apparatus were installed, and then the inside of the flask was purged with nitrogen. 170g of Methyl Ethyl Ketone (MEK) and 12.5g of methanol (MeOH) were added to a flask purged with nitrogen, and then 2.25g of Azobisisobutyronitrile (AIBN) was added thereto to be completely dissolved. Then, a monomer mixture of 60g of methacrylic acid (MAA), 100g of benzyl methacrylate (BzMA), 15g of Methyl Methacrylate (MMA) and 75g of Styrene (SM) was added thereto as a monomer, heated to a temperature of 80 ℃, and then polymerized for 6 hours to prepare an alkali developable adhesive resin 2 (weight average molecular weight 40,000g/mol, glass transition temperature 102 ℃, solid content 50 wt%, acid value 156 mgKOH/g).

Measurement of weight average molecular weight (Mw) of alkali developable adhesive resin

The alkali developable binder resin prepared in one of preparation example 1 and preparation example 2 was dissolved in tetrahydrofuran at a concentration of 1.0 (w/w)% in THF (about 0.5 (w/w)%, based on the solid content), and then filtered using a syringe filter with a pore size of 0.45 μm, followed by injecting 20 μ l into GPC. The mobile phase of GPC was Tetrahydrofuran (THF) and flowed at a flow rate of 1.0mL/min, and analyzed at 40 ℃. Columns were used in which 1 Agilent PLgel5 μm Guard (7.5X 50mm) and 2 Agilent PLgel5 μm Mixed D (7.5X 300mm) were connected in series. Agilent 1260Infinity II System, RIDetector was used for measurements at 40 ℃.

STD A(Mp):791,000/27,810/945

STD B(Mp):282,000/10,700/580

STD C(Mp):126,000/4,430/370

STD D(Mp):51,200/1,920/162

< examples and comparative examples: preparation of photosensitive resin composition and Dry film Photoresist >

The photoinitiator was dissolved in an organic solvent according to the composition shown in table 1 below, and then a photopolymerizable compound and an alkali-developable binder resin were added thereto and mixed for about 1 hour using a mechanical stirrer to prepare a photosensitive resin composition.

The resulting photosensitive resin composition was coated on a 16 μm pet film using a coating bar. The coated photosensitive resin composition layer was dried using a hot air oven at a drying temperature of 80 ℃ for 5 minutes, and the thickness of the photosensitive resin composition layer after drying was 25 μm.

A photosensitive laminate (dry film photoresist) was prepared by laminating a protective film (polyethylene) on the dried photosensitive resin composition layer.

[ Table 1]

Comparative example 2: preparation of photosensitive resin composition and Dry film Photoresist

An experiment was conducted based on [0088] and [0093] of patent document 1 to reproduce example 4 of patent document 1 (Japanese patent laid-open No. 2006-106287).

1. Preparation of photosensitive resin composition

Based on the description in example 4 of cited invention 1, the following components were mixed for about 1 hour using a mechanical stirrer based on 300 parts by weight of the "alkali developable binder resin" obtained in preparation example 1 to prepare a photosensitive resin composition.

< Components of photosensitive resin composition >

(1)100 parts by weight of 2, 2-bis (4- (methacryloxypentaethoxy) phenyl) propane

(2)50 parts by weight of EO, PO-modified urethane dimethacrylate

(3)50 parts by weight of polypropylene glycol diacrylate (number of propylene glycol chains: 7)

(4) Photoinitiator (2): 25 parts by weight of benzophenone, 1.0 part by weight of 2- (o-chlorophenyl) -4, 5-diphenylimidazole dimer, and 1.0 part by weight of diethylaminobenzophenone

(5)5.0 parts by weight of a photochromic agent

(6)0.15 parts by weight of a dye

(7) Mixing solvent: 477 parts by weight of acetone (boiling point: 56 ℃), 26.5 parts by weight of toluene (boiling point: 110 ℃) and 26.5 parts by weight of propylene glycol monomethyl ether (boiling point: 146.4 ℃) [ low-boiling solvent having a boiling point of 100 ℃ or lower ]: the weight ratio of the high boiling point solvent with the boiling point of more than 115 ℃ ═ 19:1]

2. Preparation of Dry film Photoresist

The resulting photosensitive resin composition was coated on a 25 μm pet film using a coating bar. The coated photosensitive resin composition layer was dried using a hot air oven at a drying temperature of 80 ℃ for 5 minutes, and the thickness of the photosensitive resin layer after drying was 25 μm.

< test examples >

The physical properties of the dry film photoresists prepared in examples and comparative examples were measured by the following methods, and the results are shown in table 3.

1. Measurement of the amount of exposure (unit: MJ/cm)²)

The dry film photoresist prepared in one of examples and comparative examples was laminated on a brush-polished copper clad laminate having a thickness of 1.6 mm. Here, HAKUTO MACH 610i was used at a substrate preheating roll temperature of 120 ℃, a laminator roll temperature of 115 ℃ and a roll pressure of 4.0kgf/cm²And laminating at a roller speed of 2.0 min/m.

Using a 41-stage exposure meter (step table) manufactured by Stouffer Graphic Arts Equipment and FDi-3 manufactured by ORC, a dry film photoresist laminated on a copper clad laminate was irradiated with ultraviolet rays having a wavelength of 405nm at an exposure amount such that the number of remaining stages was 15 stages, and then allowed to stand for 15 minutes. Then, the mixture was washed with 1.0 wt% Na₂CO₃The development is performed under the development conditions of the aqueous solution jet method. At this time, the amount of energy at which the determined remaining number of stages becomes 15 stages is measured.

2.1 measurement of resolution (unit: μm)

Data formed at intervals of 0.5 μm from 4 μm to 20 μm were used so that the width of the circuit lines and the pitch between the circuit lines became 1:1 after development in the laminate, and ultraviolet rays having a wavelength of 405nm were irradiated with an exposure amount of 15 stages remaining, using a step table (step table) manufactured by Stouffer Graphic Arts Equipment and FDi-3 manufactured by ORC, and left for 15 minutes. Then, the mixture was washed with 1.0 wt% Na₂CO₃The development is performed under the development conditions of the aqueous solution jet method.

Thereafter, using a ZEISS AXIOPHOT microscope, the resolution was determined from the values measured by making the interval between the circuit lines and the interval between the non-circuit lines 1:1.

3. Confirmation of air bubbles (unit: air bubbles/mm)²)

For the dry film photoresists prepared in one of examples and comparative examples, after removing the PET film and the PE film, the number of bubbles having a diameter of less than 1 μm (bubbles/mm) existing in the photosensitive resin layer (unit area: 1mm × 1mm) was confirmed using a polarization microscope²)。

4. Confirmation of defects after exposure/development (unit: defect/mm)²)

In order to make the width of the circuit lines and the pitch between the circuit lines 1:1 after development, the laminate was irradiated with ultraviolet rays having a wavelength of 405nm at an exposure amount such that the number of remaining stages was 15 stages using a 41-stage exposure meter (step table) manufactured by Stouffer Graphic Arts Equipment and FDi-3 manufactured by ORC, and then left to stand for 15 minutes. Then, the mixture was washed with 1.0 wt% Na₂CO₃The development is performed under the development conditions of the aqueous solution jet method.

For each of the developed dry film photoresists prepared in examples and comparative examples, the number of defects (defect/mm) of 0.5 μm or more and 3 μm or less was examined by observing the upper and lower surfaces of the resist within a unit area (1 mm) using an electron microscope²). The surface and cross section of the photosensitive resin layer obtained in each example and comparative example were observed using a field emission scanning electron microscope (FE-SEM, manufactured by Hitachi, magnification 3000 times).

[ Table 2]

Referring to table 2 and fig. 1, it was confirmed that 1/mm was present in the photosensitive resin layer of the photosensitive laminate of the example²The following bubbles having a diameter of less than 1 μm and no large bubbles having a diameter of 1 μm to 5 μm.

Further, even after the photosensitive resin layer of the example was exposed to ultraviolet rays and developed with an alkali solution, it was confirmed that defects having a diameter of 0.5 μm or more and 3 μm or less were not substantially generated, or 1 piece/mm was generated²The following drawbacks.

It was also observed that since a small amount of bubbles having a diameter of less than 1 μm were present in the photosensitive resin layer of the example, defects in forming fine wiring when a circuit board was produced using the photosensitive laminate material could be reduced while achieving high density and sensitivity with high reliability, thereby enabling formation of finer wiring.

On the other hand, even when energy comparable to that of example was used in the photosensitive resin laminate of comparative example 1, it was difficult to achieve resolution similar to that of example. In particular, it was confirmed that even when 350mJ/cm was used in the photosensitive resin laminate of comparative example 2²The resolution equivalent to that of the embodiment is also difficult to achieve.

In addition, it was confirmed that 15 pieces/mm were generated in the dry film photoresists of comparative examples 1 and 2²The above bubbles having a diameter of less than 1 μm. Referring to fig. 3, it was confirmed that many (8 defects/mm) occurred after exposing the photosensitive resin layer to light and then developing with an alkali solution²Above) a defect having a diameter of 0.5 μm or more and 3 μm or less.

Claims

1. A photosensitive laminate comprising: a support substrate; and a photosensitive resin layer comprising a photopolymerizable compound and an alkali-developable binder resin, the photopolymerizable compound comprising a polyfunctional (meth) acrylate compound having three or more functionalities,

wherein 5/mm are present in the photosensitive resin layer²The following bubbles having a diameter of less than 1 μm.

2. The photosensitive laminate as claimed in claim 1, wherein the photosensitive resin layer does not contain bubbles having a diameter of 1 μm to 5 μm.

3. The photosensitive laminate as claimed in claim 1, wherein 3/mm exists in 50% of the total thickness of the photosensitive resin layer from the opposite surface of the interface between the support substrate and the photosensitive resin layer²The following bubbles having a diameter of less than 1 μm.

4. The photosensitive laminate as claimed in claim 1, wherein the support substrate has a thickness of 1 to 100 μm, and the photosensitive resin layer has a thickness of 1 to 100 μm.

5. The photosensitive laminate as claimed in claim 1, wherein the photosensitive resin layer has 3 pieces/mm after exposure to ultraviolet rays and development with alkali²The following defects having a cross-sectional diameter of 0.3 μm to 4 μm.

6. The photosensitive laminate as claimed in claim 1, wherein the multifunctional (meth) acrylate compound having three or more functionalities has a structure in which three or more C1 to C10 alkyleneoxy groups and three or more (meth) acrylate functional groups are bonded to C1 to C20 central groups.

7. The photosensitive laminate as claimed in claim 1, wherein the multifunctional (meth) acrylate compound having three or more functionalities includes a compound of the following chemical formula 1:

[ chemical formula 1]

In the chemical formula 1, the first and second,

R₄is hydrogen or C1 to C10 alkyl，

R₅Is a C1 to C10 alkylene group,

R₆is a p-valent functional group containing a central group of C1 to C20,

n2 is an integer from 1 to 20, an

p is R₆The number of the functional groups substituted, and is an integer of 3 to 10.

8. The photosensitive laminate of claim 1, wherein the photopolymerizable compound further comprises a monofunctional (meth) acrylate compound or a difunctional (meth) acrylate compound.

9. The photosensitive laminate of claim 8, wherein the monofunctional (meth) acrylate compound comprises a (meth) acrylate containing a C1 to C10 alkyleneoxy group.

10. The photosensitive laminate of claim 8, wherein the photopolymerizable compound comprises: a monofunctional (meth) acrylate compound including a (meth) acrylate containing a C1 to C10 alkyleneoxy group; and a multifunctional (meth) acrylate compound having three or more functionalities, the multifunctional (meth) acrylate compound having a structure in which three or more C1 to C10 alkyleneoxy groups and three or more (meth) acrylate functional groups are bonded to a C1 to C20 central group.

11. The photosensitive laminate as claimed in claim 8, wherein the photopolymerizable compound comprises 110 parts by weight or more and 500 parts by weight or less of the multifunctional (meth) acrylate compound having three or more functionalities, based on 100 parts by weight of the monofunctional (meth) acrylate compound.

12. The photosensitive laminate as claimed in claim 8, wherein the photopolymerizable compound comprises 500 parts by weight or more and 1000 parts by weight or less of the difunctional (meth) acrylate compound based on 100 parts by weight of the polyfunctional (meth) acrylate compound having three or more functionalities.

13. The photosensitive laminate according to claim 1, wherein the alkali-developable binder resin has a weight average molecular weight of 20,000 to 300,000g/mol and a glass transition temperature of 20 ℃ or more and 150 ℃ or less.

14. The photosensitive laminate as claimed in claim 1, wherein the alkali-developable adhesive resin has an acid value in the range of 100 to 300 mgKOH/g.

15. A method for producing a circuit board using the photosensitive laminate as claimed in claim 1.

16. A method for producing the photosensitive laminate as claimed in claim 1, comprising the steps of:

coating a resin composition on a supporting substrate, followed by drying, the resin composition comprising: a mixed solvent containing a high-boiling point solvent having a boiling point of 115 ℃ or higher and a low-boiling point solvent having a boiling point of 100 ℃ or lower; a photopolymerizable compound comprising a multifunctional (meth) acrylate compound having a functionality of three or more; an alkali developable binder resin; and a photo-initiator, wherein the photo-initiator is a photoinitiator,

wherein the mixed solvent contains the high boiling point solvent having a boiling point of 115 ℃ or higher and the low boiling point solvent having a boiling point of 100 ℃ or lower in a weight ratio of 1:2 to 1: 18.

17. The method of producing a photosensitive laminate according to claim 16, wherein the mixed solvent contains the high boiling point solvent having the boiling point of 115 ℃ or more and the low boiling point solvent having the boiling point of 100 ℃ or less in a weight ratio of 1:3 to 1: 15.

18. The method for producing a photosensitive laminate according to claim 16, wherein the high boiling point solvent having a boiling point of 115 ℃ or higher comprises at least one organic solvent selected from the group consisting of butanol, dimethylformamide, N-methyl-2-pyrrolidone, γ -butyrolactone, butyl carbitol, butyl cellosolve, methyl cellosolve, butyl acetate, diethylene glycol methyl ethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propylene glycol methyl ether propionate, dipropylene glycol dimethyl ether, cyclohexanone, and propylene glycol monomethyl ether acetate PGMEA.

19. The method of producing a photosensitive laminate according to claim 16, wherein the low boiling point solvent having a boiling point of 100 ℃ or less comprises at least one organic solvent selected from the group consisting of methyl ethyl ketone, methanol, ethanol, acetone, tetrahydrofuran, and isopropyl alcohol.

20. The method of producing a photosensitive laminate according to claim 16, wherein the polyfunctional (meth) acrylate compound having three or more functionalities has a structure in which three or more C1 to C10 alkyleneoxy groups and three or more (meth) acrylate functional groups are bonded to a C1 to C20 central group.

21. The method of preparing a photosensitive laminate according to claim 16, wherein the multifunctional (meth) acrylate compound having three or more functionalities comprises a compound of the following chemical formula 2:

[ chemical formula 2]

In the chemical formula 2, the first and second organic solvents,

R₄is hydrogen or C1 to C10 alkyl,

R₅is a C1 to C10 alkylene group,

R₆is a p-valent functional group containing a central group of C1 to C20,

n2 is an integer from 1 to 20, an

p is R₆The number of functional groups substituted thereon, and is an integer of 3 to 10.

22. The method of preparing a photosensitive laminate according to claim 16, wherein the photopolymerizable compound further comprises a monofunctional (meth) acrylate compound or a difunctional (meth) acrylate compound.

23. The method of preparing a photosensitive laminate according to claim 22, wherein the monofunctional (meth) acrylate compound comprises a (meth) acrylate containing a C1 to C10 alkyleneoxy group.

24. The method of preparing a photosensitive laminate according to claim 22, wherein the photopolymerizable compound comprises: a monofunctional (meth) acrylate compound including a (meth) acrylate containing a C1 to C10 alkyleneoxy group; and a polyfunctional (meth) acrylate compound having three or more functionalities, the polyfunctional (meth) acrylate compound having a structure in which three or more C1 to C10 alkyleneoxy groups and three or more (meth) acrylate functional groups are bonded to a C1 to C20 central group.

25. The method of preparing a photosensitive laminate according to claim 22, wherein the photopolymerizable compound comprises 110 parts by weight or more and 500 parts by weight or less of the multifunctional (meth) acrylate compound having three or more functionalities, based on 100 parts by weight of the monofunctional (meth) acrylate compound.

26. The method of preparing a photosensitive laminate according to claim 22, wherein the photopolymerizable compound comprises 500 parts by weight or more and 1000 parts by weight or less of the difunctional (meth) acrylate compound based on 100 parts by weight of the polyfunctional (meth) acrylate compound having three or more functionalities.

27. The method of preparing a photosensitive laminate according to claim 16, wherein the alkali-developable binder resin has a weight average molecular weight of 20,000 to 300,000g/mol and a glass transition temperature of 20 ℃ or more and 150 ℃ or less.

28. The method of producing a photosensitive laminate according to claim 16, wherein the alkali-developable adhesive resin has an acid value in a range of 100mgKOH/g to 300 mgKOH/g.