CN114509919A

CN114509919A - Method for manufacturing interlayer insulating film and interlayer insulating film

Info

Publication number: CN114509919A
Application number: CN202111338423.0A
Authority: CN
Inventors: 樋口伦也; 西村飒太; 桥本壮一; 荒井贵
Original assignee: Goo Chemical Industries Co Ltd
Current assignee: Goo Chemical Industries Co Ltd
Priority date: 2020-11-16
Filing date: 2021-11-12
Publication date: 2022-05-17
Also published as: TWI830081B; TW202225204A; JP2022079201A; JP7382068B2

Abstract

The invention provides a method for manufacturing an interlayer insulating film, which can manufacture an interlayer insulating film with excellent copper plating adhesion. The method for manufacturing an interlayer insulating film includes a coating film forming step, an exposure step, and a thermosetting step. In the coating film forming step, a coating film of a photosensitive composition containing (A) a carboxyl group-containing resin and (B)) A photopolymerization initiator, (C) a photopolymerizable compound, and (D) an epoxy resin. In the exposure step, the concentration of the dopant is 3mW/cm²～300mW/cm²The coating is exposed to ultraviolet rays having a wavelength of 320 to 390 nm. In the thermosetting step, the coating after the exposure step is thermally cured at a temperature of 140 ℃ or higher.

Description

Method for manufacturing interlayer insulating film and interlayer insulating film

Technical Field

The present disclosure relates to a method for manufacturing an interlayer insulating film and an interlayer insulating film, and more particularly, to a method for manufacturing an interlayer insulating film and an interlayer insulating film including a coating film forming step, an exposure step, and a heat curing step.

Background

With the progress of miniaturization and high performance of electronic components and electric components, semiconductor elements, semiconductor packages, printed wiring boards, flexible wiring boards, and the like to be used have been increased in density and definition, and photosensitive interlayer insulating films capable of forming fine opening patterns have been required. Such an interlayer insulating film is required to have excellent characteristics such as resolution, copper plating adhesion, and insulation reliability. As a material for forming the interlayer insulating film, a photosensitive resin composition containing an epoxy resin, an ethylenically unsaturated bond-containing compound, a photopolymerization initiator, and a nitrogen-containing cyclic compound having a cyclic structure of 10 or more rings is known (see patent document 1).

Recently, for further densification, the via hole processing size by laser irradiation has reached a limit, and a shift from the laser via hole method to a via hole etching method capable of forming a via hole with a smaller diameter has been studied.

Thus, in the present day when the pattern of the interlayer insulating film is becoming finer, the copper plating adhesion of the interlayer insulating film cannot be satisfied by using the above-mentioned conventional materials.

Patent document 1: japanese patent laid-open publication No. 2018-138968

Disclosure of Invention

The present disclosure addresses the problem of providing a method for producing an interlayer insulating film, which can produce an interlayer insulating film having excellent copper plating adhesion, and an interlayer insulating film.

A method for manufacturing an interlayer insulating film according to one embodiment of the present disclosure includes a film formation step, an exposure step, and a thermosetting step. In the film formation step, a film of a photosensitive composition containing (a) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photopolymerizable compound, and (D) an epoxy resin is formed. In the exposure step, the amount of the light is 3mW/cm²～300mW/cm²The coating is exposed to ultraviolet light having a wavelength of 320nm to 390 nm. In the thermosetting step, the coating after the exposure step is thermally cured at a temperature of 140 ℃ or higher.

An interlayer insulating film according to an embodiment of the present disclosure is obtained by the above method for manufacturing an interlayer insulating film.

An interlayer insulating film according to one embodiment of the present disclosure contains a photosensitive composition passing 3mW/cm²～300mW/cm²Ultraviolet rays having a wavelength of 320 to 390nm and heat at a temperature of 140 ℃ or higher. The photosensitive composition contains (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photopolymerizable compound, and (D) an epoxy resin.

Drawings

Fig. 1A is a scanning electron microscope photograph showing the surface state of the interlayer insulating film after the surface roughening step in the example.

Fig. 1B is a scanning electron microscope photograph showing the surface state of the interlayer insulating film after the surface roughening step in the comparative example.

Detailed Description

< method for producing interlayer insulating film >

The method for manufacturing an interlayer insulating film according to the present embodiment includes a coating film forming step, an exposure step, and a thermosetting step.

The inventors have intensively studied a method for producing an interlayer insulating film in order to solve the problems of the present disclosure. As a result, it was found that when a film of a photosensitive composition containing (a) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photopolymerizable compound and (D) an epoxy resin is exposed to ultraviolet light and then the exposed film is thermally cured to produce an interlayer insulating film, the interlayer insulating film is produced by irradiating the film with illuminance (mW/cm) in a specific range²) The copper plating adhesion can be improved by performing exposure and thermal curing at a temperature (DEG C) within a specific range, and the present invention has been completed.

The reason why the above-described effects are exhibited by the method for manufacturing an interlayer insulating film according to the present embodiment having the above-described configuration is not necessarily clear, but can be estimated as follows, for example. That is, it is considered that an appropriate crosslinked structure can be formed in the coating film by exposure to light in a specific range of illuminance in the exposure step, and that a sea-island structure can be formed in the coating film by heating the coating film having the appropriate crosslinked structure formed therein at a temperature in a specific range in the subsequent thermosetting step. As a result, it is considered that a roughened shape having a high anchor effect can be obtained in the surface roughening step described later, and excellent copper plating adhesion can be exhibited by the roughened shape. As described above, according to the present disclosure, it is possible to provide a method for manufacturing an interlayer insulating film, which can manufacture an interlayer insulating film having excellent copper plating adhesiveness.

The method for manufacturing an interlayer insulating film according to the present embodiment may further include, in addition to the above steps, the steps of: a step of alkali-developing the coating after the exposure step (hereinafter, also referred to as an alkali-developing step) after the exposure step; after the heat curing process, at a rate of more than 300mW/cm²A step of irradiating the coating film after the heat curing step with ultraviolet rays having a wavelength of 320 to 390nm (hereinafter, also referred to as a post-irradiation step); after the alkali development step and before the thermosetting step, the amount of the alkali added was 3mW/cm²～300mW/cm²A step of irradiating the coating film after the alkali development step with ultraviolet rays having a wavelength of 320 to 390nm (hereinafter, also referred to as a pre-irradiation step).

The method for manufacturing an interlayer insulating film according to the present embodiment may further include a step of performing surface roughening treatment on the film after the thermosetting step (hereinafter, also referred to as a surface roughening step) after the thermosetting step, or may further include a step of plating the film after the thermosetting step (hereinafter, also referred to as a plating step) after the thermosetting step.

Hereinafter, each step will be explained.

[ coating film Forming Process ]

In this step, a coating film of a photosensitive composition containing (a) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photopolymerizable compound, and (D) an epoxy resin is formed. The photosensitive composition is described below.

This step is performed, for example, by: the photosensitive composition is applied to form a coating film, and the coating film is dried by removing the organic solvent or the like to form a film as a dry film. The coating is performed on a film made of polyethylene terephthalate, for example. Examples of the method for coating include spin coating, dip coating, roll coating, curtain coating, spin coating, screen printing, blade coating, and applicator coating.

For drying of the coating film, the coating film may be heated. The heating temperature is preferably 40 to 130 ℃, more preferably 70 to 120 ℃. The heating time is preferably 1 minute to 5 hours, more preferably 2 minutes to 1 hour. The heating may be performed at a temperature of 1 stage, or at a temperature of 2 stages or more.

The thickness of the formed coating film is preferably 1 μm to 1000 μm, more preferably 5 μm to 500 μm, and still more preferably 10 μm to 100 μm.

The obtained coating film is laminated on a surface of a core material or the like on which a conductor wiring is formed, for example, by heating using a vacuum laminator or the like. At this time, the surface layer portion of the conductor wiring is roughened with an etchant or the like. The temperature of the heat lamination is, for example, 50 to 150 ℃, the pressure is, for example, 0.1 to 2MPa, and the time is, for example, 10 seconds to 10 minutes. In this manner, a coating film formed on the core material can be obtained.

[ Exposure Process ]

In this step, the amount of the catalyst is 3mW/cm²～300mW/cm²The coating formed in the coating forming step is exposed to ultraviolet light having a wavelength of 320 to 390nm at an illuminance (hereinafter also referred to as illuminance (I)). This step is performed, for example, by exposing the coating film to ultraviolet light through a negative mask having a non-exposed portion including a circular pattern having a predetermined diameter. The illuminance and the exposure amount are values of the surface of the film to be exposed or irradiated with ultraviolet rays, and can be measured by a known measurement method.

In the exposure step, it is considered that an appropriate crosslinked structure can be formed on the coating film by exposure with the illumination intensity (I) in the above-described specific range. The illumination intensity (I) is less than 3mW/cm²In the case of the formation of crosslinks, the formation of crosslinks was insufficient, exceeding 300mW/cm²In the case of this, since excessive crosslinking is formed, the anchor effect of the roughened shape formed in the surface roughening step is insufficient, and the copper plating adhesion is deteriorated. For this reason, in the secondary coating film forming stepIt is preferable that the amount of the solution is not more than 300mW/cm until the heat curing step²The coating is irradiated with ultraviolet rays having a wavelength of 320nm to 390 nm.

Examples of the light source for exposing ultraviolet light having a wavelength of 320nm to 390nm include a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, a xenon lamp, and an LED.

The illuminance (I) is preferably 5mW/cm²More preferably 10mW/cm²Above, more preferably 20mW/cm²Above, particularly preferably 30mW/cm²The above. In this case, the crosslinked structure of the coating film is more appropriate, the anchor effect of the roughened shape is further improved, and the copper plating adhesion is further improved. The illuminance (I) is preferably 270mW/cm²Hereinafter, more preferably 250mW/cm²Hereinafter, more preferably 220mW/cm²Hereinafter, it is particularly preferably 200mW/cm²The following. In this case, the crosslinked structure of the coating film is more appropriate, the anchor effect of the roughened shape is further improved, and the copper plating adhesion is further improved.

The exposure time in the exposure step is preferably 0.1 to 1000 seconds, more preferably 0.5 to 200 seconds, and still more preferably 1 to 100 seconds.

The exposure amount in the exposure step is preferably 30mJ/cm²Above, more preferably 100mJ/cm²The concentration is more preferably 200mJ/cm²The above. In this case, it is considered that the crosslinked structure of the coating film can be further adjusted, the anchor effect of the roughened shape can be further improved, and the copper plating adhesion can be further improved. The exposure amount is preferably 2000mJ/cm²Hereinafter, more preferably 1500mJ/cm²Hereinafter, more preferably 1000mJ/cm²The following. At this time, the resolution is improved.

In the photosensitive composition, the double bond reaction rate (hereinafter, also referred to as the double bond reaction rate (I)) after the exposure step and before the alkali development step is preferably 15% to 70%. In this case, it is considered that the crosslinked structure formed in the exposure step is more appropriate, and the anchor effect of the roughened shape can be further improved. The double bond reaction rate (I) is more preferably 20% to 65%, and still more preferably 30% to 60%. The "double bond reactivity" refers to (C) contained in the photosensitive composition) The reaction rate of the crosslinking reaction of the ethylenic double bond of the photopolymerizable compound (a) carboxyl group-containing resin, etc. The double bond reaction rate can be measured by infrared absorption spectroscopy (IR) of the coating film. Specifically, 1630cm in the IR spectrum of the coating film formed in the coating film forming step^-1Standard value (S) of peak area of (a)₀) And 1630cm of the coating film measured after exposure or irradiation with ultraviolet light^-1Standard value (S) of peak area of (a)₁) With (S)₀-S₁)×100/S₀Calculated by the following formula (%). Standard value (S)₀Or S₁) Means 1630cm^-1Measured value of the area of the peak (P)₀Or P₁) And 750cm whose area is not changed by exposure or irradiation^-1Measured value of the area of the peak (R)₀Or R₁) Ratio of (P)₀/R₀Or P₁/R₁)。

[ alkali development Process ]

In this step, the coating after the exposure step is subjected to alkali development. This enables patterning of the coating film. This step is performed by bringing an alkali developing solution into contact with the film.

Examples of the alkali developer include an aqueous alkaline solution in which at least 1 of basic compounds such as sodium carbonate, sodium hydroxide, potassium hydroxide, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1, 8-diazabicyclo- [5.4.0] -7-undecene, 1, 5-diazabicyclo- [4.3.0] -5-nonene and the like are dissolved.

Examples of the method of bringing the alkali developing solution into contact with the film include a method of spraying the alkali developing solution onto the film, a method of immersing the film in the alkali developing solution, and the like. After contacting with the alkali developing solution, the film is preferably washed with pure water or the like.

In the photosensitive composition, the double bond reaction rate (hereinafter, also referred to as the double bond reaction rate (II)) after the alkali development step and before the thermosetting step is preferably 15% to 70%. In this case, it is considered that the crosslinked structure of the coating film before the thermosetting step is more appropriate, and the anchor effect of the roughened shape can be further improved. The double bond reaction rate (II) is more preferably 20% to 65%, and still more preferably 30% to 60%.

[ front irradiation Process ]

In this step, the amount of the catalyst is 3mW/cm²～300mW/cm²The coating after the alkali development step and before the heat curing step is irradiated with ultraviolet rays having a wavelength of 320 to 390nm at an illuminance (hereinafter, also referred to as illuminance (II)). It is considered that by irradiating the coating after the alkali development with ultraviolet rays at the illuminance (II) in the above range before the heat curing step, the crosslinked structure of the coating before the heat curing step can be further moderated, the anchor effect of the roughened shape can be further improved, and the copper plating adhesion can be further improved. If the Illumination Intensity (II) is less than 3mW/cm²The anchoring effect is not so much improved by the pre-irradiation step. It is considered that if the illuminance (II) exceeds 300mW/cm²If the cross-linked structure of the coating film is excessive by the pre-irradiation step, the anchoring effect of the roughened shape is reduced, and the copper plating adhesion is reduced.

Examples of the light source for irradiating ultraviolet rays having a wavelength of 320nm to 390nm include a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, a xenon lamp, and an LED.

The illuminance (II) is preferably 5mW/cm²More preferably 7mW/cm²More preferably 10mW/cm²The above. The illuminance (II) is preferably 270mW/cm²Hereinafter, more preferably 250mW/cm²The following.

The exposure amount in the pre-irradiation step is preferably 50mJ/cm²Above, more preferably 100mJ/cm²The concentration is more preferably 200mJ/cm²The above. The exposure amount is preferably 2000mJ/cm²Hereinafter, more preferably 1500mJ/cm²Hereinafter, more preferably 1000mJ/cm²The following.

[ Heat curing Process ]

In this step, the coating after the exposure step is thermally cured at a temperature of 140 ℃ or higher. Thus, the sea-island structure is formed in the coating film having the appropriate cross-linked structure, and a roughened shape having a high anchoring effect is formed in the surface roughening step.

Examples of the method of heat curing include a method of heating a coating film. Examples of the heating method include a method using a hot plate, a heating furnace, a hot air drying furnace, and the like.

The heating temperature is above 140 ℃. If the heating temperature is less than 140 ℃, the formation of the sea-island structure of the coating film in the thermosetting step is insufficient, and a roughened shape having a high anchoring effect cannot be obtained in the surface roughening step, and the copper plating adhesion is deteriorated. The heating temperature is preferably 150 ℃ or higher, more preferably 160 ℃ or higher, and still more preferably 170 ℃ or higher. The heating temperature is preferably 220 ℃ or lower, more preferably 210 ℃ or lower, and still more preferably 200 ℃ or lower.

The heating time is preferably 1 minute to 500 minutes, more preferably 10 minutes to 200 minutes, and still more preferably 100 minutes to 200 minutes. By setting the heating time to the above range, the sea-island structure can be sufficiently formed in the coating film.

In the photosensitive composition, the double bond reaction rate after the thermosetting step (hereinafter, also referred to as the double bond reaction rate (III)) is preferably 80% to 100%. In this case, it is considered that the crosslinking of the coating film proceeds more moderately by the heating in the thermosetting step, the anchor effect of the roughened shape can be further improved, and the copper plating adhesion can be further improved. The double bond reaction rate (III) is more preferably 90% to 100%, still more preferably 93% to 100%.

[ post-irradiation step ]

In the working procedure, the concentration is more than 300mW/cm²The coating after the heat curing step is irradiated with ultraviolet rays having a wavelength of 320 to 390nm (hereinafter, also referred to as "illuminance (III)"). It is considered that by irradiating the coating after the heat curing step with ultraviolet rays with the illuminance (III) in the above range, the crosslinked structure of the coating can be further moderated, the anchor effect of the roughened shape can be further improved, and as a result, the copper plating adhesion can be further improved.

The illumination intensity (III) exceeds 300mW/cm². If it is usedThe illumination intensity (III) is 300mW/cm²Hereinafter, the anchoring effect is not so much improved by the post irradiation step. The illuminance (III) is preferably 400mW/cm²Above, more preferably 600mW/cm²Above, more preferably 800mW/cm²The above. The upper limit of the illuminance (III) is not particularly limited, and may be 2500mW/cm²Hereinafter, preferably 2000mW/cm²The following.

The exposure amount in the post-irradiation step is preferably 300mJ/cm²Above, more preferably 500mJ/cm²Above, more preferably 1000mJ/cm²The above. The exposure amount is preferably 4000mJ/cm²Hereinafter, more preferably 3000mJ/cm²More preferably 2500mJ/cm²The following.

In the photosensitive composition, the double bond reaction rate (hereinafter, also referred to as the double bond reaction rate (IV)) after the post-irradiation step is preferably 95% to 100%. In this case, it is considered that the crosslinking of the coating film proceeds more moderately by the post-irradiation step, the anchor effect of the roughened shape can be further improved, and the copper plating adhesion can be further improved. The double bond reaction rate (IV) is more preferably 97% to 100%, and still more preferably 99% to 100%.

[ surface roughening Process ]

In this step, the coating after the thermosetting step is subjected to surface roughening treatment. This can further improve the copper plating adhesion.

In this step, a roughened shape having a high anchoring effect is formed by the crosslinked structure of the coating film formed appropriately in the exposure step and the thermosetting step.

Examples of the method of the surface roughening treatment include a method of performing a chemical treatment using an oxidizing agent such as a permanganate solution or a dichromate solution, a physical treatment using fine particles, and the like. Among these, a method of performing chemical treatment is preferable, and a method of contacting the film with an oxidizing agent in a solution is more preferable. As the oxidizing agent, an oxidizing agent that can be obtained as a desmear solution can be used. Examples of the method of contacting the oxidizing agent include a method of immersing the coating in an oxidizing agent solution. Examples of the permanganate include potassium permanganate and sodium permanganate. Examples of the dichromate include ammonium dichromate and potassium dichromate. The temperature of the oxidizing agent solution is, for example, 50 to 100 ℃, preferably 60 to 90 ℃. The time for immersion is, for example, 1 minute to 30 minutes, preferably 3 minutes to 20 minutes.

Before contacting with the oxidizing agent solution, the coating film is preferably subjected to a swelling treatment using a desmearing swelling solution or the like. The temperature of the swelling solution in the swelling treatment is, for example, 50 to 100 ℃ and the time of the swelling treatment is, for example, 1 minute to 1 hour. After the swelling treatment, the surface of the film is preferably washed with hot water.

After contacting with the oxidizing agent solution, the surface of the film is preferably washed with hot water, and the residue of the desmear solution on the surface of the film is preferably removed with a neutralizing solution or the like, and after removing the residue, the surface of the film is preferably washed with water.

[ plating Process ]

In this step, the coating after the thermosetting step is plated. By this step, the plating layer can be formed on the roughened coating film having a high anchor effect formed in the surface roughening step, and thus an interlayer insulating film having excellent copper plating adhesion can be obtained.

The present process is generally performed by forming an initial wiring by an electroless plating process, followed by forming a metal layer on the initial wiring by an electroplating process.

The electroless plating treatment and the electroplating treatment may be performed by a known method. The coating film on which a metal is deposited by electroless plating and electroplating is preferably heated at 100 to 250 ℃ for 1 minute to 3 hours to form a plating layer. The thickness of the formed plating layer is, for example, 1 to 200. mu.m, preferably 10 to 50 μm.

The method for manufacturing an interlayer insulating film according to the present embodiment preferably includes, after the coating film forming step, the steps of:

a1 st curing step of curing the coating film obtained in the coating film forming step with ultraviolet rays so that the double bond reaction rate is 15% to 70%, and

and a2 nd curing step of further curing the coating film after the 1 st curing step by heat so that the double bond reaction rate is 80% to 100%.

The double bond reaction rate in the 1 st curing step is preferably 20% to 65%. The double bond reaction rate in the 2 nd curing step is preferably 85% to 100%, more preferably 90% to 100%.

Next, the photosensitive composition will be described.

(photosensitive composition)

The photosensitive composition contains (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photopolymerizable compound, and (D) an epoxy resin. The photosensitive composition may contain, in addition to the above components, (E) an organic filler, (F) an inorganic filler, (G) an additive, and the like, in a range in which the effects of the present disclosure are not impaired.

((A) carboxyl group-containing resin)

(A) The carboxyl group-containing resin (hereinafter also referred to as (a) resin) is a resin having a carboxyl group.

(A) The resin is preferably a photopolymerizable resin such as (a1) a carboxyl group-containing resin having a bisphenol fluorene skeleton (hereinafter also referred to as (a1) resin) or (a2) a carboxyl group-containing resin having a diphenolaldehyde varnish skeleton (hereinafter also referred to as (a2) resin).

((A1) resin)

(A1) The resin is a reactant of an intermediate, which is a reactant of an epoxy compound (a1) having a bisphenol fluorene skeleton represented by, for example, the following formula (1) wherein R is R, and an acid anhydride, and an ethylenically unsaturated group-containing carboxylic acid (a2)₁～R₈Each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom. (A1) The resin is synthesized by reacting an epoxy compound (a1) having a bisphenol fluorene skeleton represented by the following formula (1) with an ethylenically unsaturated group-containing carboxylic acid (a2), and reacting the intermediate thus obtained with an acid anhydride.

In the formula (1), R₁～R₈Each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogen. Namely, R in the formula (1)₁～R₈Each of which may be a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom. This is because, even if a hydrogen atom in the aromatic ring is substituted with a low molecular weight alkyl group or a halogen atom, the physical properties of the (a1) resin are not adversely affected, and instead, the heat resistance and flame retardancy of a cured product of the photosensitive composition containing the (a1) resin may be improved by the substitution.

(A1) The resin can be synthesized, for example, by the following procedure. First, at least a part of epoxy groups in an epoxy compound (a1) having a bisphenol fluorene skeleton represented by formula (1) is reacted with an unsaturated group-containing carboxylic acid (a2) to synthesize an intermediate. The epoxy group is a group represented by the following formula (2). The intermediate has a structure represented by the following formula (3) produced by a ring-opening addition reaction of an epoxy group and an unsaturated group-containing carboxylic acid (a 2). That is, the intermediate has a secondary hydroxyl group generated by a ring-opening addition reaction of an epoxy group and an unsaturated group-containing carboxylic acid (a2) in the structure represented by formula (3). In the formula (3), A is a carboxylic acid residue containing an unsaturated group.

Next, the secondary hydroxyl groups in the intermediate are reacted with an anhydride. Thus, a resin (a1) was obtained.

Examples of the acid anhydride include acid dianhydride (a3) and acid monoanhydride (a 4). When the acid anhydride contains the acid monoanhydride (a4), the (a1) resin has a bisphenol fluorene skeleton represented by formula (1) and a structure represented by formula (4) below.

The structure represented by formula (4) is produced by reacting the secondary hydroxyl group in the structure represented by formula (3) of the intermediate with the acid anhydride group in the acid monoanhydride (a 4). In the formula (4), A is a carboxylic acid residue containing an unsaturated group, and B is an acid monoanhydride residue.

When the acid anhydride contains the acid dianhydride (A3), the carboxyl group-containing resin (a1) has a bisphenol fluorene skeleton represented by formula (1) and a structure represented by formula (5).

The structure represented by formula (5) is produced by reacting two anhydride groups in the acid dianhydride (a3) with two secondary hydroxyl groups in the intermediate, respectively. That is, the structure represented by formula (5) is produced by crosslinking two secondary hydroxyl groups with each other with acid dianhydride (a 3). In addition, there are cases where two secondary hydroxyl groups present in one molecule of the intermediate are crosslinked with each other and two secondary hydroxyl groups present in two molecules of the intermediate are crosslinked with each other. The molecular weight can be increased if two secondary hydroxyl groups respectively present in two molecules of the intermediate are cross-linked to each other. In the formula (5), A is a carboxylic acid residue containing an unsaturated group, and D is an acid dianhydride residue.

The (a1) resin can be obtained by reacting the secondary hydroxyl group in the intermediate with an acid anhydride. When the acid anhydride comprises an acid dianhydride (a3) and an acid monoanhydride (a4), a part of the secondary hydroxyl groups in the intermediate is reacted with the acid dianhydride (a3), and another part of the secondary hydroxyl groups in the intermediate is reacted with the acid monoanhydride (a 4). Thereby, a resin (a1) can be synthesized. In this case, the resin (a1) has a bisphenol fluorene skeleton represented by formula (1), a structure represented by formula (4), and a structure represented by formula (5).

(A1) The resin may further have a structure represented by the following formula (6). The structure represented by formula (6) is produced by reacting only one of the two anhydride groups in acid dianhydride (a3) with a secondary hydroxyl group in the intermediate. In the formula (6), A is a carboxylic acid residue containing an unsaturated group, and D is an acid dianhydride residue.

When a part of the epoxy groups in the epoxy compound (a1) remains unreacted during the synthesis of the intermediate, the resin (a1) may have a structure represented by formula (2), that is, an epoxy group. In addition, when a part of the structure represented by formula (3) in the intermediate remains unreacted, (a1) resin may have a structure represented by formula (3).

When the acid anhydride contains the acid dianhydride (A3), the structure represented by formula (2) and the structure represented by formula (6) in the (a1) resin can be reduced or substantially eliminated by optimizing the reaction conditions at the time of synthesizing the (a1) resin.

As described above, the (a1) resin may have a bisphenol fluorene skeleton represented by formula (1), may have a structure represented by formula (4) in the case where the acid anhydride contains an acid monoanhydride (a4), and may have a structure represented by formula (5) in the case where the acid anhydride contains an acid dianhydride (a 3). Further, in the case where the acid anhydride contains the acid monoanhydride (a4), the (a1) resin may have at least one of the structure represented by formula (2) and the structure represented by formula (3). When the acid anhydride includes the acid dianhydride (A3), the resin (a1) may have at least one of the structure represented by formula (2) and the structure represented by formula (6). Further, in the case where the acid anhydride contains acid monoanhydride (a4) and acid dianhydride (A3), (a1) the resin may have at least one of the structure represented by formula (2), the structure represented by formula (3), and the structure represented by formula (6).

When the epoxy compound (a1) itself has a secondary hydroxyl group, that is, for example, when n is 1 or more in formula (7) described later, the resin (a1) may have a structure resulting from the reaction between the secondary hydroxyl group in the epoxy compound (a1) and an acid anhydride.

The structure of the resin (a1) is reasonably analogized based on the technical common knowledge, and the structure of the resin (a1) cannot be identified by analysis in reality. The reason for this is as follows. When the epoxy compound (a1) itself has a secondary hydroxyl group (for example, when n is 1 or more in formula (7)), the structure of the resin (a1) greatly changes depending on the number of secondary hydroxyl groups in the epoxy compound (a 1). In addition, when the intermediate is reacted with the acid dianhydride (a3), as described above, there are a case where two secondary hydroxyl groups present in one molecule of the intermediate are crosslinked with each other by the acid dianhydride (a3) and a case where two secondary hydroxyl groups present in two molecules of the intermediate are crosslinked with each other by the acid dianhydride (a 3). Therefore, the finally obtained (a1) resin contains a plurality of molecules having different structures, and it is difficult to identify the structure of the (a1) resin even when the resin is analyzed.

(A1) The resin has photoreactivity by having an ethylenically unsaturated group derived from the unsaturated group-containing carboxylic acid (a 2). Therefore, the (a1) resin can impart photosensitivity, specifically ultraviolet curability, to the photosensitive composition. The resin (a1) has a carboxyl group derived from an acid anhydride, and can impart developability with an alkaline aqueous solution containing at least one of an alkali metal salt and an alkali metal hydroxide to the photosensitive composition. Further, in the case where the acid anhydride contains an acid dianhydride (A3), the resin (a1) has its molecular weight adjusted by crosslinking with the acid dianhydride (A3). Thus, a resin (a1) having an appropriately adjusted acid value and molecular weight can be obtained. In the case where the acid anhydride contains the acid dianhydride (A3) and the acid monoanhydride (a4), the molecular weight and the acid value of the (a1) resin can be easily adjusted by controlling the amounts of the acid dianhydride (A3) and the acid monoanhydride (a4) and the amount of the acid monoanhydride (a4) relative to the acid dianhydride (A3).

(A1) The weight average molecular weight of the resin is preferably 700 to 10000. When the weight average molecular weight is 700 or more, the adhesiveness of the coating film formed of the photosensitive composition can be suppressed, and the insulation reliability and plating resistance of the interlayer insulating film can be improved. Further, if the weight average molecular weight is 10000 or less, the developability of the photosensitive composition with an alkaline aqueous solution is particularly improved. The weight average molecular weight is more preferably 900 to 8000, and further preferably 1000 to 5000.

(A1) The acid value of the resin is preferably 60mgKOH/g to 140 mgKOH/g. In this case, the developability of the photosensitive composition is particularly improved. The acid value is more preferably from 80mgKOH/g to 135mgKOH/g, and still more preferably from 90mgKOH/g to 130 mgKOH/g.

(A1) The weight average molecular weight (Mw) of the resin was calculated from the results of molecular weight measurement by Gel Permeation Chromatography (GPC). The molecular weight measurement by GPC can be performed under the following conditions, for example.

GPC apparatus: SHODEX SYSTEM 11 manufactured by SHOWA DENKO-DENKO

Column: the 4 SHODEX KF-800P, KF-005, KF-003 and KF-001 are connected in series

Mobile phase: THF (tetrahydrofuran)

Flow rate: 1 mL/min

Column temperature: 45 deg.C

A detector: RI (Ri)

Conversion: polystyrene

The reaction conditions for synthesizing the raw material of the (a1) resin and the (a1) resin will be described in detail.

The epoxy compound (a1) has, for example, a structure represented by the following formula (7). N in the formula (7) is, for example, a number in the range of 0 to 20. In order to appropriately control the molecular weight of the (A1) resin, the average value of n is particularly preferably in the range of 0 to 1. When the average value of n is in the range of 0 to 1, particularly when the acid anhydride contains the acid dianhydride (a3), it is easy to suppress an excessive increase in molecular weight due to addition of the acid dianhydride (a 3).

Examples of the unsaturated group-containing carboxylic acid (a2) include compounds having only 1 ethylenically unsaturated group in one molecule. Examples of the unsaturated group-containing carboxylic acid (a2) include acrylic acid, methacrylic acid, ω -carboxy-polycaprolactone (n ≈ 2) monoacrylate, crotonic acid, cinnamic acid, 2-acryloyloxyethylsuccinic acid, 2-methacryloyloxyethylsuccinic acid, 2-acryloyloxyethylphthalic acid, 2-methacryloyloxyethylphthalic acid, 2-acryloyloxypropylphthalic acid, 2-methacryloyloxypropylphthalic acid, 2-acryloyloxyethylsalic maleic acid, 2-methacryloyloxyethylmaleic acid, β -carboxyethyl acrylate, 2-acryloyloxyethyltetrahydrophthalic acid, 2-methacryloyloxyethyltetrahydrophthalic acid, 2-acryloyloxyethylhexahydrophthalic acid, and the like, 2-methacryloyloxyethyl hexahydrophthalic acid, and the like. The unsaturated group-containing carboxylic acid (a2) preferably contains acrylic acid.

The epoxy compound (a1) and the unsaturated group-containing carboxylic acid (a2) can be reacted by a known method. For example, an unsaturated group-containing carboxylic acid (a2) is added to a solvent solution of an epoxy compound (a1), and if necessary, a thermal polymerization inhibitor and a catalyst are added thereto and mixed with stirring to obtain a reactive solution. The intermediate can be obtained by reacting the reactive solution at a temperature of preferably 60 to 150 c, more preferably 80 to 120 c, by a conventional method. Examples of the solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; acetates such as ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, and propylene glycol monomethyl ether acetate; dialkyl glycol ethers, and the like. Examples of the thermal polymerization inhibitor include hydroquinone and hydroquinone monomethyl ether. Examples of the catalyst include tertiary amines such as benzyldimethylamine and triethylamine; quaternary ammonium salts such as trimethylbenzylammonium chloride and methyltriethylammonium chloride; triphenylphosphine, triphenylantimony, and the like.

The catalyst preferably comprises triphenylphosphine. That is, the epoxy compound (a1) is preferably reacted with the unsaturated group-containing carboxylic acid (a2) in the presence of triphenylphosphine. In this case, the ring-opening addition reaction of the epoxy group in the epoxy compound (a1) and the unsaturated group-containing carboxylic acid (a2) is particularly promoted, and a reaction rate (conversion rate) of usually 95% or more, preferably 97% or more, and more preferably substantially 100% can be achieved. Therefore, the intermediate having the structure represented by formula (3) can be obtained in high yield.

The amount of the unsaturated group-containing carboxylic acid (a2) to 1 mole of the epoxy group of the epoxy compound (a1) when the epoxy compound (a1) and the unsaturated group-containing carboxylic acid (a2) are reacted is preferably in the range of 0.8 to 1.2 moles. In this case, excellent photosensitivity and storage stability of the photosensitive composition can be obtained.

It is also preferable to react the epoxy compound (a1) with the unsaturated group-containing carboxylic acid (a2) under bubbling of air. In this case, the addition polymerization reaction of the unsaturated group is suppressed, and the increase in the molecular weight of the intermediate and the gelation of the solution of the intermediate can be suppressed. In addition, excessive coloring of the (a1) resin as a final product can be suppressed.

The intermediate obtained in this manner has a hydroxyl group generated by the reaction of the epoxy group in the epoxy compound (a1) with the carboxyl group of the unsaturated group-containing carboxylic acid (a 2).

The acid dianhydride (a3) is a compound having two anhydride groups. Examples of the acid dianhydride (a3) include anhydrides of tetracarboxylic acids. Examples of the acid dianhydride (a3) include 1,2,4, 5-benzenetetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, methylcyclohexene tetracarboxylic dianhydride, naphthalene-1, 4,5, 8-tetracarboxylic dianhydride, ethylene tetracarboxylic dianhydride, 9 '-bis (3, 4-dicarboxyphenyl) fluorene dianhydride, glycerol bis (trimellitic anhydride ester) monoacetate, ethylene glycol bis (trimellitic anhydride ester), 3, 3', 4,4 '-diphenylsulfone tetracarboxylic dianhydride, 1,3,3a,4,5,9 b-hexahydro-5 (tetrahydro-2, 5-dioxo-3-furanyl) naphtho [ 1,2-c ] furan-1, 3-dione, 1,2,3, 4-butanetetracarboxylic dianhydride, 3, 3', 4, 4' -biphenyltetracarboxylic dianhydride, and the like. The acid dianhydride (a3) preferably contains 3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride. That is, D in the formulae (5) and (6) preferably contains a3, 3 ', 4, 4' -biphenyltetracarboxylic dianhydride residue. In this case, the adhesiveness of the coating film formed of the photosensitive composition can be suppressed while ensuring good developability of the photosensitive composition, and the insulation reliability and plating resistance of the interlayer insulating film can be improved. The amount of 3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride is preferably 20 to 100 mol%, more preferably 40 to 100 mol%, based on the total amount of acid dianhydrides (a 3).

The acid monoanhydride (a4) is a compound having 1 acid anhydride group. Examples of the acid monoanhydride (a4) include anhydrides of dicarboxylic acids. Examples of the acid monoanhydride (a4) include phthalic anhydride, 1,2,3, 6-tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, methylsuccinic anhydride, maleic anhydride, citraconic anhydride, glutaric anhydride, cyclohexane-1, 2, 4-tricarboxylic acid-1, 2-anhydride, and itaconic anhydride. The acid monoanhydride (a4) preferably comprises 1,2,3, 6-tetrahydrophthalic anhydride. That is, it is preferable that the (a1) resin has a structure represented by formula (4), and B in formula (4) contains a1, 2,3, 6-tetrahydrophthalic anhydride residue. In this case, the adhesiveness of the coating film formed of the photosensitive composition can be suppressed while ensuring good developability of the photosensitive composition, and the insulation reliability and plating resistance of the interlayer insulating film can be improved. The 1,2,3, 6-tetrahydrophthalic anhydride is preferably 20 to 100 mol%, more preferably 40 to 100 mol%, based on the whole amount of the monoanhydride (a 4).

The intermediate and the acid anhydride can be reacted by a known method. For example, an acid anhydride is added to a solvent solution of the intermediate, and if necessary, a thermal polymerization inhibitor and a catalyst are added and mixed with stirring to obtain a reactive solution. The resin (A1) can be obtained by reacting the reactive solution at a temperature of preferably 60 to 150 ℃ and more preferably 80 to 120 ℃ by a conventional method. As the solvent, catalyst and polymerization inhibitor, any suitable one may be used, and the solvent, catalyst and polymerization inhibitor used in the synthesis of the intermediate may be used as it is.

The catalyst preferably comprises triphenylphosphine. That is, the intermediate is reacted with the acid anhydride, preferably in the presence of triphenylphosphine. In this case, the reaction of the secondary hydroxyl group in the intermediate with the acid anhydride is particularly promoted, and a reaction rate (conversion rate) of usually 90% or more, preferably 95% or more, more preferably 97% or more, and further preferably substantially 100% can be achieved. Therefore, the resin (a1) having at least one of the structure represented by formula (4) and the structure represented by formula (5) can be obtained in high yield.

In the case where the acid anhydride contains the acid dianhydride (a3) and the acid monoanhydride (a4), the amount of the acid dianhydride (a3) is preferably 0.05 to 0.24 mol based on1 mol of the epoxy group of the epoxy compound (a 1). The amount of the acid monoanhydride (a4) is preferably 0.3 to 0.7 mol based on1 mol of the epoxy group in the epoxy compound (a 1). In this case, the resin (a1) having an appropriately adjusted acid value and molecular weight can be easily obtained.

((A2) resin)

(A2) The carboxyl group-containing resin having a diphenolaldehyde varnish skeleton is a carboxyl group-containing resin having a diphenolaldehyde varnish skeleton in place of the bisphenol fluorene skeleton in the (a1) resin. (A2) The resin is a reactant of an intermediate, which is a reactant of a diphenol novolak-type epoxy resin with an ethylenically unsaturated group-containing carboxylic acid (a2), and an acid anhydride. (A2) The resin can be synthesized by the same method as that for the resin (a 1). The preferable ranges of the weight average molecular weight and the acid value of the (a2) resin are the same as those of the (a1) resin described above.

((A3) resin)

(A) The resin may contain other resins having photopolymerization properties (hereinafter, also referred to as (A3) other than the (a1) resin and the (a2) resin. Examples of the resin (a3) include resins having a carboxyl group and an ethylenically unsaturated group. Examples of the resin (a3) include resins that are reactants of an intermediate, which is a reactant of an epoxy compound (g1) having two or more epoxy groups in one molecule, and an ethylenically unsaturated compound (g2), and at least one of a polycarboxylic acid and an anhydride thereof. (A3) The resin is obtained, for example, by adding a compound (g3) which is at least one of a polycarboxylic acid and an anhydride thereof to an intermediate obtained by reacting an epoxy group in an epoxy compound (g1) with a carboxyl group in an ethylenically unsaturated compound (g 2). Examples of the epoxy compound (g1) include suitable epoxy compounds such as cresol novolak type epoxy compounds, phenol novolak type epoxy compounds, and biphenol novolak type epoxy compounds. Examples of the ethylenically unsaturated compound (g2) include acrylic acid, methacrylic acid, and ω -carboxy-polycaprolactone (n ≈ 2) monoacrylate. Examples of the compound (g3) include polycarboxylic acids such as phthalic acid, tetrahydrophthalic acid and methyltetrahydrophthalic acid, and anhydrides of these polycarboxylic acids.

Examples of the resin (a3) include resins that are reaction products of a polymer of an ethylenically unsaturated monomer containing an ethylenically unsaturated compound having a carboxyl group and an ethylenically unsaturated compound having an epoxy group. The (a3) resin is obtained by reacting an ethylenically unsaturated compound having an epoxy group with a part of the carboxyl groups in the polymer. Examples of the ethylenically unsaturated compound having an epoxy group include glycidyl (meth) acrylate and 3, 4-epoxycyclohexylmethyl (meth) acrylate.

(A) The proportion of the photopolymerizable resin in the resin is preferably 30% by mass or more, more preferably 50% by mass or more, still more preferably 90% by mass or more, and particularly preferably 100% by mass. In this case, the heat resistance and insulation reliability of the interlayer insulating film can be further improved, the viscosity of the film formed of the photosensitive composition can be sufficiently suppressed, and the alkali developability of the photosensitive composition can be further improved.

(A) The resin preferably comprises (a1) resin. By using a resin (a1) having a bisphenol fluorene skeleton as the resin (a), the copper plating adhesion of the interlayer insulating film can be further improved.

(A) The resin may contain a resin having a carboxyl group and no photopolymerization property (hereinafter, also referred to as a (a) resin) in addition to the resin having a photopolymerization property.

Examples of the resin (a) include polymers of ethylenically unsaturated monomers containing an ethylenically unsaturated compound having a carboxyl group. Examples of the ethylenically unsaturated compound having a carboxyl group include monomers such as acrylic acid, methacrylic acid, and ω -carboxy-polycaprolactone (n ≈ 2) monoacrylate; and reaction products of compounds such as pentaerythritol triacrylate and pentaerythritol trimethacrylate with dibasic acid anhydrides.

(A) The proportion of the resin to the entire photosensitive composition (solid content) is preferably 5 to 85 mass%, more preferably 10 to 75 mass%, and still more preferably 25 to 50 mass%. The entire photosensitive composition (solid content) is the total of all components except for volatile components such as a solvent in the photosensitive composition.

((B) photopolymerization initiator)

(B) The photopolymerization initiator is a component capable of improving the photosensitivity of the photosensitive composition. (B) The photopolymerization initiator preferably contains at least 1 kind selected from, for example, an α -aminoalkylbenzophenone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, and an oxime ester-based photopolymerization initiator. In this case, when the photosensitive composition is exposed to light such as ultraviolet light, high photosensitivity can be imparted to the photosensitive composition. (B) The photopolymerization initiator further preferably contains (B1) an acylphosphine oxide photopolymerization initiator. In this case, the photosensitive composition can be provided with high photosensitivity, and the composition is less colored and can maintain high transparency.

The α -aminoalkylphenone-based photopolymerization initiator may contain at least one component selected from, for example, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, and 2- (dimethylamino) -2- [ (4-methylphenyl) methyl ] -1- [4- (4-morpholino) phenyl ] -1-butanone.

(B1) The acylphosphine oxide-based photopolymerization initiator may include, for example, monoacylphosphine oxide-based photopolymerization initiators selected from 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,4, 6-trimethylbenzoyl-ethyl-phenyl-phosphinic acid ester and the like, bis- (2, 6-dichlorobenzoyl) phenylphosphine oxide, bis- (2, 6-dichlorobenzoyl) -2, 5-dimethylphenylphosphine oxide, bis- (2, 6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis- (2, 6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis- (2, 6-dimethoxybenzoyl) phenylphosphine oxide, bis- (2, 6-dimethoxybenzoyl) -2, at least one component selected from bisacylphosphine oxide photopolymerization initiators such as 4, 4-trimethylpentylphosphine oxide, bis- (2, 6-dimethoxybenzoyl) -2, 5-dimethylphenylphosphine oxide, bis- (2,4, 6-trimethylbenzoyl) phenylphosphine oxide, and (2,5, 6-trimethylbenzoyl) -2,4, 4-trimethylpentylphosphine oxide.

The oxime ester photopolymerization initiator may contain, for example, at least one component selected from 1, 2-octanedione-1- [4- (phenylthio) -2- (oxo-benzoyloxime) ], ethanone-1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] -1- (O-acetyloxime).

The photosensitive composition may further contain an appropriate photopolymerization accelerator, sensitizer, and the like. For example, the photosensitive composition may contain a hydroxy ketone selected from 1-hydroxy-cyclohexyl-phenyl-ketone, methyl phenylglyoxylate, 1- [4- (2-hydroxyethoxy) -phenyl ] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl ] phenyl } -2-methyl-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and the like; benzoin and alkyl ethers thereof; acetophenones such as acetophenone and benzil dimethyl ketal; anthraquinones such as 2-methylanthraquinone; thioxanthones such as 2, 4-dimethylthioxanthone, 2, 4-diethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone and 2, 4-diisopropylthioxanthone; benzophenones such as benzophenone, 4-benzoyl-4' -methyldiphenyl sulfide, and bis (diethylamino) benzophenone; xanthones such as 2, 4-diisopropylxanthone; α -hydroxyketones such as 2-hydroxy-2-methyl-1-phenyl-propan-1-one; and 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholino-1-propanone and the like. The photosensitive composition may contain, together with the photopolymerization initiator (B), an appropriate photopolymerization accelerator such as a tertiary amine compound such as ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, and 2-dimethylaminoethyl benzoate, and a sensitizer. The photosensitive composition may contain at least one of a photopolymerization initiator for visible light exposure and a photopolymerization initiator for near-infrared light exposure as necessary. The photosensitive composition may contain, together with (B) a photopolymerization initiator, a coumarin derivative such as 7-diethylamino-4-methylcoumarin, a carbocyanine type, a xanthene type, or the like as a sensitizer for laser exposure.

(B) The photopolymerization initiator preferably contains (B2) a hydroxyketone photopolymerization initiator in addition to (B1) the acylphosphine oxide photopolymerization initiator. That is, the photosensitive composition preferably contains (B2) a hydroxyketone photopolymerization initiator. In this case, a higher photosensitivity can be imparted to the photosensitive composition than in the case where the (B2) hydroxyketone photopolymerization initiator is not contained. Thus, when the film formed of the photosensitive composition is irradiated with ultraviolet rays and cured, the film can be sufficiently cured from the surface to the deep portion thereof. Examples of the hydroxyketone photopolymerization initiator (B2) include 1-hydroxy-cyclohexyl-phenyl-ketone, methyl phenylglyoxylate, 1- [4- (2-hydroxyethoxy) -phenyl ] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl ] phenyl } -2-methyl-propan-1-one, and 2-hydroxy-2-methyl-1-phenyl-propan-1-one.

(B1) The mass ratio of the acylphosphine oxide-based photopolymerization initiator to the hydroxyketone-based photopolymerization initiator (B2), (B1): (B2)), is preferably 1: 0.01-1: 10, in the range of the total weight of the composition. In this case, the curability in the vicinity of the surface of the film formed of the photosensitive composition and the curability in the deep part can be improved in a well-balanced manner.

(B) The photopolymerization initiator preferably also contains (B3) bis (diethylamino) benzophenone. That is, the photosensitive composition preferably contains (B1) an acylphosphine oxide-based photopolymerization initiator and (B3) bis (diethylamino) benzophenone, or contains (B1) an acylphosphine oxide-based photopolymerization initiator, (B2) a hydroxyketone-based photopolymerization initiator and (B3) bis (diethylamino) benzophenone. In this case, when the coating film formed of the photosensitive composition is partially exposed to light and then developed, the curing of the unexposed portion can be suppressed, and the resolution is particularly high. Therefore, a very fine pattern can be formed from the cured product of the photosensitive composition. In particular, when an interlayer insulating layer of a multilayer printed wiring board is formed from a photosensitive composition and a small-diameter hole for a through hole is provided in the interlayer insulating layer by photolithography, the small-diameter hole can be formed precisely and easily.

The proportion of (B3) bis (diethylamino) benzophenone is preferably 0.5 to 20 parts by mass relative to 100 parts by mass of (B1) the acylphosphine oxide-based photopolymerization initiator. When the amount of (B3) bis (diethylamino) benzophenone is 0.5 parts by mass or more, the resolution is particularly high. Further, if the amount of (B3) bis (diethylamino) benzophenone is 20 parts by mass or less, (B3) bis (diethylamino) benzophenone hardly hinders electrical insulation of a cured product of the photosensitive composition.

(B) The proportion of the photopolymerization initiator to 100 parts by mass of the carboxyl group-containing resin (a) is preferably 0.1 to 30 parts by mass, and more preferably 1 to 25 parts by mass.

(B) The proportion of the photopolymerization initiator to the entire photosensitive composition (solid content) is preferably 0.001 to 1% by mass, and more preferably 0.01 to 0.1% by mass.

((C) photopolymerizable Compound)

(C) The photopolymerizable compound can impart photocurability to the photosensitive composition. (C) The photopolymerizable compound usually has an ethylenic double bond. (C) The photopolymerizable compound has an ethylenic double bond, and thus a crosslinking reaction can be performed between the (C) photopolymerizable compounds and each other and/or between the (C) photopolymerizable compound and the (a) resin having an ethylenic double bond, and a crosslinked structure can be formed in the film. Examples of the group containing an ethylenic double bond include a vinyl group, an allyl group, and a (meth) acryloyl group. Examples of the photopolymerizable compound (C) include monofunctional (meth) acrylates such as 2-hydroxyethyl (meth) acrylate; and polyfunctional (meth) acrylates such as diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epsilon-caprolactone-modified pentaerythritol hexaacrylate, and tricyclodecane dimethanol di (meth) acrylate.

(C) The photopolymerizable compound preferably contains a trifunctional compound, i.e., a compound having 3 unsaturated bonds in one molecule. In this case, the resolution of the film formed of the photosensitive composition at the time of exposure and development is improved, and the developability of the photosensitive composition with an alkaline aqueous solution is particularly improved. Examples of the trifunctional compound include trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethoxylated isocyanuric acid tri (meth) acrylate, ε -caprolactone-modified tris- (2-acryloyloxyethyl) isocyanurate, and ethoxylated glycerin tri (meth) acrylate.

(C) The photopolymerizable compound may comprise a prepolymer. Examples of the prepolymer include prepolymers obtained by polymerizing a monomer having an ethylenically unsaturated bond and then adding an ethylenically unsaturated group, and oligo (meth) acrylate prepolymers. Examples of the oligo (meth) acrylate prepolymer include epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) acrylate, alkyd (meth) acrylate, silicone (meth) acrylate, and spiro alkyl (meth) acrylate.

(C) The proportion of the photopolymerizable compound to 100 parts by mass of the carboxyl group-containing resin (a) is preferably 1 to 50 parts by mass, more preferably 10 to 45 parts by mass, and still more preferably 21 to 40 parts by mass.

(C) The proportion of the photopolymerizable compound to the entire photosensitive composition (solid content) is preferably 1 to 50% by mass, more preferably 5 to 30% by mass, and still more preferably 10 to 20% by mass.

((D) epoxy resin)

(D) The epoxy resin can impart thermosetting properties to the photosensitive composition. (D) The epoxy resin preferably comprises a crystalline epoxy resin. In this case, the developability of the photosensitive composition can be improved. The (D) epoxy resin may further contain a non-crystalline epoxy resin. Here, the "crystalline epoxy resin" is an epoxy resin having a melting point, and the "amorphous epoxy resin" is an epoxy resin having no melting point.

Examples of the crystalline epoxy resin include 1,3, 5-tris (2, 3-epoxypropyl) -1,3, 5-triazine-2, 4,6(1H,3H,5H) -trione, hydroquinone-type crystalline epoxy resin (product number YDC-1312 manufactured by Nippon iron chemical & materials Co., Ltd. as a specific example), biphenyl-type crystalline epoxy resin (product number YX-4000 manufactured by Mitsubishi chemical Co., Ltd. as a specific example), diphenyl ether-type crystalline epoxy resin (product number YSLV-80DE manufactured by Nippon iron chemical & materials Co., Ltd. as a specific example), bisphenol-type crystalline epoxy resin (product numbers YSLV-70XY, YSLV-80XY manufactured by Nippon iron chemical & materials Co., Ltd. as a specific example), tetraphenylolethane-type crystalline epoxy resin (product number GTR-1800 manufactured by Nippon chemical Co., Ltd. as a specific example), A bisphenol fluorene type crystalline epoxy resin (specifically, the epoxy resin having the structure represented by formula (7) described above) and the like.

The crystalline epoxy resin preferably has 2 epoxy groups in 1 molecule.

The crystalline epoxy resin preferably has an epoxy equivalent of 150 to 300 g/eq. The epoxy equivalent is the gram mass of a crystalline epoxy resin containing 1 gram equivalent of an epoxy group. The crystalline epoxy resin has a melting point. The melting point of the crystalline epoxy resin is, for example, 70 to 180 ℃.

(D) The epoxy resin preferably contains a crystalline epoxy resin having a melting point of 110 ℃ or less. In this case, the alkali developability of the photosensitive composition is further improved. Examples of the crystalline epoxy resin having a melting point of 110 ℃ or lower include biphenyl type epoxy resins, biphenyl ether type epoxy resins, bisphenol fluorene type crystalline epoxy resins, and the like.

Examples of the amorphous epoxy resin include phenol novolac type epoxy resin (product number EPICLON-775 manufactured by DIC), cresol novolac type epoxy resin (product number EPICLON-695 manufactured by DIC), bisphenol A novolac type epoxy resin (product number EPICLON-865 manufactured by DIC), bisphenol A type epoxy resin (product number jER1001 manufactured by Mitsubishi chemical corporation), bisphenol F type epoxy resin (product number jER4004P manufactured by Mitsubishi chemical corporation), bisphenol S type epoxy resin (product number EPICLON EXA-1514 manufactured by DIC), bisphenol AD type epoxy resin, biphenol novolac type epoxy resin (product number NC-3000 manufactured by Nippon chemical corporation), Hydrogenated bisphenol A type epoxy resin (product No. ST-4000D manufactured by Nippon chemical & materials Co., Ltd., as a specific example), naphthalene type epoxy resin (product No. EPICLON HP-4032, EPICLON HP-4700, EPICLON HP-4770 manufactured by DIC Co., Ltd., as a specific example), t-butylphthalide type epoxy resin (product No. EPICLON HP-820 manufactured by DIC Co., Ltd., as a specific example), dicyclopentadiene type epoxy resin (product No. EPICLON HP-7200 manufactured by DIC Co., Ltd., as a specific example), adamantane type epoxy resin (product No. ADAMANTATE X-E-201 manufactured by Cinese Co., Ltd., as a specific example), and specific bifunctional type epoxy resin (product No. YL7175-500, YL7175-1000 manufactured by Mitsubishi chemical Co., Ltd., product No. EPICLON TSR-960, EPICLON TERTER-601, EPICLON TERS-477, EPICLON, EPICLON TSR-250-80BX, EPICLON1650-75MPX, EPICLON EXA-4850, EPICLON EXA-4816, EPICLON EXA-4822, EPICLON EXA-9726; YSLV-120TE, a rubber-like core-shell polymer-modified bisphenol A type epoxy resin (MX-156, a product number of Bell Corp., as a specific example), a rubber-like core-shell polymer-modified bisphenol F type epoxy resin (MX-136, a product number of Bell Corp., as a specific example), and the like.

(D) The total of the equivalents of epoxy groups contained in the epoxy resin is preferably 0.7 to 2.5 times, more preferably 0.7 to 2.3 times, and still more preferably 0.7 to 2.0 times, based on1 equivalent of carboxyl groups contained in the carboxyl group-containing resin (a). The total of the equivalents of epoxy groups contained in the crystalline epoxy resin is preferably 0.1 to 2.0 times, more preferably 0.2 to 1.9 times, and still more preferably 0.3 to 1.5 times, based on1 equivalent of carboxyl groups contained in the carboxyl group-containing resin (a).

(D) The proportion of the epoxy resin to the entire photosensitive composition (solid content) is preferably 5 to 40% by mass, more preferably 8 to 30% by mass, and still more preferably 10 to 20% by mass.

The photosensitive composition may contain a curing agent, a curing accelerator, and the like for curing the epoxy resin in addition to the epoxy resin (D).

Examples of the curing agent include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1- (2-cyanoethyl) -2-ethyl-4-methylimidazole; amine compounds such as dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N-dimethylbenzylamine, and 4-methyl-N, N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; phosphorus compounds such as triphenylphosphine; an acid anhydride; phenol; a thiol; a lewis acid amine complex;

salts and the like. When the photosensitive composition contains a curing agent, the proportion of the curing agent to the entire photosensitive composition (solid content) is usually 1 to 50% by mass.

((E) organic Filler)

(E) The organic filler can impart thixotropy to the photosensitive composition. Examples of the (E) organic filler include (E1) an organic filler having a carboxyl group. (E1) Some of the carboxyl groups of the organic filler may be exposed on the surface of the organic filler (E1).

(E1) The organic filler has high compatibility with the photosensitive composition, and can impart stronger thixotropy to the photosensitive composition. In addition, when the photosensitive composition contains the (E1) organic filler having a carboxyl group, the alkali developability of the photosensitive composition can be further improved.

When the photosensitive composition contains the (E1) organic filler, the unevenness of the cured layer due to the fluidity of the photosensitive composition can be reduced. This makes it easy to make the thickness of the cured product layer uniform. In this case, the photosensitive composition may not contain a rheology control agent.

(E1) The carboxyl group of the organic filler is formed as a side chain of a product thereof by polymerizing or crosslinking a carboxylic acid monomer such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. The carboxylic acid monomer has, for example, a carboxyl group and a polymerizable unsaturated double bond. (E1) The organic filler improves the thixotropy of the photosensitive composition, thereby improving the stability (particularly, storage stability) of the photosensitive composition. Further, since the (E1) organic filler has a carboxyl group, the developability of a cured product containing the photosensitive composition can be improved, and the compatibility with a crystalline epoxy resin can be improved to prevent crystallization in the photosensitive composition. As for the carboxyl group content of the (E1) organic filler, for example, the acid value of the (E1) organic filler is preferably 1mgKOH/g to 60mgKOH/g in terms of the acid value based on acid-base titration. If the acid value is less than 1mgKOH/g, the stability of the photosensitive composition and the developability of the cured product may be lowered. If the acid value is more than 60mgKOH/g, the reliability of moisture resistance of the cured product may be lowered. (E1) The acid value of the organic filler is more preferably 3mgKOH/g to 40 mgKOH/g.

(E1) The organic filler preferably has hydroxyl groups. Some of the hydroxyl groups may be exposed on the surface of the organic filler (E1). In this way, the (E1) organic filler has a hydroxyl group, and thus the dispersibility of the (E1) organic filler in the photosensitive composition is further improved.

(E1) The average primary particle diameter of the organic filler is preferably 1 μm or less. When the average primary particle size of the organic filler (E1) is 1 μm or less, the thixotropy of the photosensitive composition can be improved with high efficiency. Therefore, the stability of the photosensitive composition is further improved. In addition, when the average primary particle size of the organic filler (E1) is 1 μm or less, the roughness of the rough surface formed on the cured product can be made fine. As a result, the anchor effect increases as the surface area of the cured product increases, and the adhesion between the rough surface and the plating layer can be further improved. (E1) The lower limit of the average primary particle diameter of the organic filler is not particularly limited, and is, for example, 0.001 μm or more. (E) The average primary particle diameter of the organic filler was measured as D50 using a laser diffraction particle size distribution measuring apparatus. (E1) The average primary particle diameter of the organic filler is more preferably 0.4 μm or less, and still more preferably 0.1 μm or less. In this case, the roughness of the rough surface formed on the cured product can be further reduced. In addition, scattering at the time of exposure can be suppressed in the photosensitive composition, whereby the resolution of the photosensitive composition can be further improved.

(E1) The organic filler is preferably dispersed in the photosensitive composition so as to have a maximum particle diameter of less than 1.0. mu.m, more preferably less than 0.5. mu.m. (E) The maximum particle size of the organic filler is measured by a laser diffraction particle size distribution measuring apparatus or by observing the cured product with a Transmission Electron Microscope (TEM). (E1) The organic filler may be aggregated in the photosensitive composition (for example, secondary particles may be formed), and in this case, the maximum particle diameter refers to the size of the aggregated particles. When the maximum particle diameter of the organic filler (E1) in the dispersed state is in the above range, the roughness of the rough surface formed on the cured product can be further reduced. In addition, scattering at the time of exposure is suppressed in the photosensitive composition, and thus the resolution of the photosensitive composition is further improved. In addition, the stability of the photosensitive composition is further improved. It is particularly preferable that the average primary particle diameter of the (E1) organic filler is 0.1 μm or less and the (E1) organic filler is dispersed in a particle diameter of 0.5 μm or less. When the particles are aggregated, the maximum particle diameter is generally larger than the average primary particle diameter.

(E1) The organic filler preferably contains a rubber component. In addition, the (E1) organic filler more preferably contains only a rubber component. The rubber component can impart flexibility to a cured product of the photosensitive composition. The rubber component may be composed of a resin. Examples of the rubber component include crosslinked acrylic rubber, crosslinked NBR, crosslinked MBS, crosslinked SBR, and the like. In this case, the rubber component can impart excellent flexibility to the cured product of the photosensitive composition. Further, a more appropriate rough surface can be provided to the surface of the cured product layer. Here, the rubber component contains a crosslinked structure formed when monomers constituting the polymer are copolymerized. NBR is generally a copolymer of butadiene and acrylonitrile, classified as nitrile rubber. MBS is generally a copolymer of 3 components of methyl methacrylate, butadiene and styrene, and is classified as a butadiene rubber. SBR is generally a copolymer of styrene and butadiene, classified as a styrene rubber. Specific examples of the (E1) organic filler include product No. XER-91-MEK, product No. XER-32-MEK and product No. XSK-500 manufactured by JSR. Of these (E1) organic fillers, XER-91-MEK was a crosslinked rubber (NBR) having a carboxyl group and an average primary particle diameter of 0.07. mu.m, and was provided in the form of a methyl ethyl ketone dispersion containing 15% by weight of the crosslinked rubber, and the acid value thereof was 10.0 mgKOH/g. The XER-32-MEK is a dispersion in which a polymer (linear particles) of a carboxyl-modified hydrogenated nitrile rubber is dispersed in methyl ethyl ketone so that the content thereof is 17% by weight based on the total amount of the dispersion. In addition, XSK-500 was a crosslinked rubber (SBR) having a carboxyl group and a hydroxyl group and having an average primary particle diameter of 0.07. mu.m, and was provided in the form of a methyl ethyl ketone dispersion having a content ratio of 15% by weight of the crosslinked rubber. Thus, the (E1) organic filler may be incorporated in the photosensitive composition in the form of a dispersion. That is, the rubber component may be blended in the photosensitive composition in the form of a dispersion. Specific examples of the (E1) organic filler include, in addition to the above, product No. XER-92 manufactured by JSR corporation.

(E1) The organic filler may contain a particle component other than the rubber component. Examples of such an organic filler (E1) include acrylic resin fine particles having a carboxyl group, cellulose fine particles having a carboxyl group, and the like. Examples of the acrylic resin fine particles having a carboxyl group include non-crosslinked styrene-acrylic resin fine particles, and the like. Specific examples of the non-crosslinked styrene-acrylic resin fine particles include FS-201 (average primary particle diameter 0.5 μm) product number manufactured by Nippon Paint Industrial Coatings. Specific examples of the crosslinked styrene-acrylic resin fine particles include product No. MG-351 (average primary particle diameter 1.0 μm) and product No. BGK-001 (average primary particle diameter 1.0 μm) manufactured by Nippon Paint Industrial Coatings. In addition, the (E1) organic filler may contain other particle components than the above-mentioned rubber component, acrylic resin fine particles and cellulose fine particles.

(E) The organic filler may further comprise (E1) an organic filler other than the organic filler. (E1) The organic filler other than the organic filler may not have a carboxyl group. (E1) The organic filler other than the organic filler may have an average primary particle diameter of more than 1 μm. However, from the viewpoint of efficiently obtaining thixotropy, the viewpoint of imparting a rough surface to a cured product, and the viewpoint of improving the resolution of the photosensitive composition, the photosensitive composition preferably does not contain an organic filler other than the (E1) organic filler.

(E1) The proportion of the organic filler to the whole of the organic filler (E) is preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 90% by mass or more, and particularly preferably 100% by mass. In this case, the stability of the photosensitive composition is further improved. In this case, a rough surface is further easily provided to the cured product of the photosensitive composition. This can further improve the copper plating adhesion.

(E) The proportion of the organic filler to the entire photosensitive composition (solid content) is preferably 1 to 40% by mass, more preferably 5 to 30% by mass, and still more preferably 10 to 20% by mass.

((F) inorganic Filler)

The photosensitive composition preferably contains (F) an inorganic filler. In this case, (F) the inorganic filler tends to be less corroded by the oxidizing agent used in the surface roughening step than the cured product of the photosensitive composition. Therefore, when the surface of the cured product containing the (F) inorganic filler is roughened with the oxidizing agent, the surface of the cured product can be appropriately corroded with the oxidizing agent because a portion which is easily corroded with the oxidizing agent and a portion which is not easily corroded are present in the vicinity of the surface of the cured product. This can impart a rough surface suitable for plating treatment to the cured product, and can further improve the copper plating adhesion.

Examples of the inorganic filler (F) include barium sulfate, crystalline silica, nano silica, carbon nanotube, talc, bentonite, hydrotalcite, aluminum hydroxide, magnesium hydroxide, titanium oxide, zinc oxide, and the like. (F) When the inorganic filler contains a white material such as titanium oxide or zinc oxide, the photosensitive composition and the cured product thereof can be whitened by the white material.

The proportion of the inorganic filler (F) in the photosensitive composition can be appropriately set, and is preferably 1 to 300 parts by mass, more preferably 3 to 200 parts by mass, and still more preferably 5 to 100 parts by mass, based on 100 parts by mass of the carboxyl group-containing resin (a). (F) The proportion of the inorganic filler to the entire photosensitive composition (solid content) is preferably less than 45% by mass, more preferably less than 40% by mass, still more preferably less than 35% by mass, and particularly preferably less than 20% by mass.

(F) The inorganic filler preferably contains silica (f). The silica (f) has silanol groups on the surface. The silanol group is considered to be modified by an oxidizing agent. Therefore, the surface of the silica (f) can be provided with a rough surface by the oxidizing agent. In the case where a cured product of a photosensitive composition is etched by an oxidizing agent, even a hard-to-etch portion where silica (f) on the surface of the cured product is located can be appropriately etched by the oxidizing agent. This can impart a rough surface more suitable for plating treatment to the cured product, and can further improve the copper plating adhesion.

The average particle diameter of the silica (f) is preferably 1 μm or less. The roughness of the rough surface formed on the cured product can be made fine by having the average particle diameter of the silica (f) be 1 μm or less. As a result, the anchor effect increases as the surface area of the cured product increases, and the adhesion between the rough surface and the plating layer can be further improved. The lower limit of the average particle diameter of the silica (f) is not particularly limited, and is, for example, 0.001 μm or more. (F) The average particle diameter of the inorganic filler was measured as D50 using a laser diffraction particle size distribution measuring apparatus. The average particle diameter of the silica (f) is more preferably 0.1 μm or less. In this case, the roughness of the rough surface formed on the cured product can be particularly reduced. In addition, scattering at the time of exposure can be suppressed in the photosensitive composition, and thereby the resolution of the photosensitive composition can be further improved.

The proportion of the silica (F) to the entire inorganic filler (F) is preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 90% by mass or more, and particularly preferably 100% by mass.

(F) The proportion of the inorganic filler (solid content) to the entire photosensitive composition (solid content) is preferably 1 to 60% by mass, more preferably 5 to 50% by mass, and still more preferably 10 to 40% by mass.

((G) additive)

Examples of the additive (G) include silane coupling agents, melamine or derivatives thereof, photopolymerization accelerators, sensitizers, leveling agents, thixotropic agents, polymerization inhibitors, antihalation agents, flame retardants, antifoaming agents, antioxidants, surfactants, polymer dispersants, copolymers of silicones, acrylates, and the like.

The photosensitive composition can improve the dispersibility of the inorganic filler (F) by containing a silane coupling agent. In addition, the resolution of the photosensitive composition can be improved.

The silane coupling agent contains silicon atoms and has 2-4-OCH₃Radical, -OC₂H₅Radical, -OCOCH₃And hydrolyzable groups such as a hydroxyl group. The silane coupling agent may contain a reactive group such as an amino group, an epoxy group, a vinyl group (allyl group), a methacryloyl group, a mercapto group, an isocyanate group, or a thioether group, or a methyl group, in addition to the hydrolyzable group.

Examples of the silane coupling agent include amino compounds such as 3- (2-aminoethylamino) propyldimethoxymethylsilane, 3- (2-aminoethylamino) propyltriethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane, 3-aminopropyldiethoxymethylsilane, 3-aminopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane, epoxy compounds such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyl (dimethoxy) methylsilane, and diethoxy (3-glycidoxypropyl) methylsilane, 3-acryloxypropyltrimethoxysilane, and the like, (meth) acrylates such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane and 3-methacryloxypropylmethyldiethoxysilane, vinyl compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, p-vinyltrimethoxysilane, diethoxymethylvinylsilane and vinyltris (2-methoxyethoxy) silane, allyl compounds such as allyltriethoxysilane and allyltrimethoxysilane, styryl compounds such as p-vinyltrimethoxysilane, isocyanates such as 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane, 3-ureidopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and the like, Ureas such as 3-ureidopropyltriethoxysilane, (3-mercaptopropyl) triethoxysilane, (3-mercaptopropyl) trimethoxysilane, mercapto compounds such as trimethoxysilane, thioethers such as bis (triethoxysilylpropyl) tetrasulfide, tetraethylorthosilicate, methyltrimethoxysilane, and the like.

When the photosensitive composition contains a silane coupling agent, the proportion of the silane coupling agent to the entire photosensitive composition (solid content) is preferably 0.001 to 1% by mass, and more preferably 0.01 to 0.5% by mass.

The photosensitive composition contains melamine or a derivative thereof, and thus the adhesion between an interlayer insulating film made of the photosensitive composition and a metal such as copper can be improved. In addition, the plating resistance of the interlayer insulating film can be improved.

When the photosensitive composition contains melamine or a derivative thereof, the proportion of melamine or a derivative thereof to the carboxyl group-containing resin (a) is preferably 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass. The proportion of melamine or a derivative thereof relative to the entire photosensitive composition (solid content) is preferably 0.05 to 2% by mass, and more preferably 0.1 to 1% by mass.

The photosensitive composition may contain an organic solvent. The organic solvent is used for the purpose of making the photosensitive composition into a liquid or varnish, adjusting viscosity, adjusting coatability, adjusting film formability, and the like.

Examples of the organic solvent include straight-chain, branched-chain, dibasic or polyhydric alcohols such as ethanol, propanol, isopropanol, hexanol and ethylene glycol; ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; petroleum aromatic mixed solvents such as Swasol series (manufactured by Wan petrochemical Co., Ltd.) and Solvesso series (manufactured by Exxon Chemical Co., Ltd.); cellosolves such as cellosolve and butyl cellosolve; carbitols such as carbitol and butyl carbitol; propylene glycol alkyl ethers such as propylene glycol methyl ether; polypropylene glycol alkyl ethers such as dipropylene glycol methyl ether; acetates such as ethyl acetate, butyl acetate, cellosolve acetate, carbitol acetate, etc.; dialkyl glycol ethers, and the like.

When the photosensitive composition contains an organic solvent, the amount of the organic solvent is preferably adjusted so that the organic solvent rapidly volatilizes when a coating film formed from the photosensitive composition is dried, that is, so that the organic solvent does not remain in the dried film. The proportion of the organic solvent to the entire photosensitive composition (solid content) is preferably 0 to 99.5% by mass, and more preferably 15 to 60% by mass.

< interlayer insulating film >

The interlayer insulating film of the present embodiment is manufactured by the above-described method for manufacturing an interlayer insulating film. The interlayer insulating film of the present embodiment is obtained by the above-described method for producing an interlayer insulating film, and therefore has excellent copper plating adhesion.

Further, the interlayer insulating film of the present embodiment preferably contains the above-mentioned photosensitive composition at a density of 3mW/cm²～300mW/cm²Ultraviolet rays having an illuminance of 320 to 390nm and heat at a temperature of 140 ℃ or higher.

Examples

Hereinafter, the present disclosure will be specifically described by examples.

(1) Synthesis of resins

Synthesis example 1 Synthesis of bisphenol fluorene skeleton-containing resin (A1)

A bisphenol fluorene type epoxy compound (R in formula (A) and represented by formula (A)) was charged in a four-necked flask equipped with a reflux condenser, a thermometer, an air blowing tube and a stirrer₁～R₈An epoxy compound having an epoxy equivalent of 250g/eq based on the total of hydrogen atoms) 250 parts by mass, 72 parts by mass of acrylic acid, 1.5 parts by mass of triphenylphosphine, 0.2 part by mass of methylhydroquinone, 60 parts by mass of propylene glycol monomethyl ether acetate, and 140 parts by mass of diethylene glycol monoethyl ether acetate. They were stirred under air bubbling, thereby preparing a mixture. The mixture was heated at 115 ℃ for 12 hours while stirring in a flask with bubbling of air. Thus, a solution of the intermediate was prepared. Next, 60.8 parts by mass of 1,2,3, 6-tetrahydrophthalic anhydride, 58.8 parts by mass of 3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride, and 38.7 parts by mass of propylene glycol monomethyl ether acetate were put into the solution of the intermediate in the flask. They were heated at 115 ℃ for 6 hours while stirring with bubbling air, and further at 80 ℃ for 1 hour while stirring with bubbling air. Thus, a 65% by mass solution of the carboxyl group-containing resin A-1 was obtained. The carboxyl group-containing resin A-1 had a polydispersity (Mw/Mn) of 2.15, a weight average molecular weight (Mw) of 3096 and an acid value of 105 mgKOH/g.

Synthesis example 2 Synthesis of a resin having a Diphenyl novolak skeleton (A2)

288 parts by mass of a biphenyl novolak type epoxy resin (manufactured by Nippon Kagaku K.K., product No. NC-3000-H, epoxy equivalent 288g/eq), 155 parts by mass of diethylene glycol monoethyl ether acetate, 0.2 part by mass of methylhydroquinone, 72 parts by mass of acrylic acid, and 3 parts by mass of triphenylphosphine were charged in a four-necked flask equipped with a reflux condenser, a thermometer, an air blowing tube, and a stirrer to prepare a mixture. The mixture was heated at a temperature of 115 ℃ for 12 hours in a flask while stirring with bubbling of air. Thus, a solution of the intermediate was prepared.

Then, 91.2 parts by mass of tetrahydrophthalic anhydride and 90 parts by mass of diethylene glycol monoethyl ether acetate were added to the solution of the intermediate in the flask, and the mixture was heated at 90 ℃ for 4 hours while stirring with bubbling of air. Thus, a 65 mass% solution of the carboxyl group-containing resin A-2 was obtained. The weight-average molecular weight of the carboxyl group-containing resin A-2 was 8120, and the acid value was 76 mgKOH/g.

(2) Preparation of photosensitive composition

Among the components shown in table 1 below, powdery components were dispersed in a carboxyl group-containing resin by a three-roll mill in advance, and then all the components were stirred and mixed at 35 ℃ in a flask to obtain a photosensitive composition.

The details of each component shown in table 1 are as follows.

- (A) carboxyl group-containing resin

Resin A-1: the resin (65 mass% solution) having a bisphenol fluorene skeleton (a1) synthesized above.

Resin A-2: the above-synthesized (A2) resin having a diphenolaldehyde varnish skeleton (65 mass% solution)

- (B) photopolymerization initiator

Photopolymerization initiator a: 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide. Manufactured by BASF corporation. Product number Irgacure TPO.

Photopolymerization initiator B: 1-hydroxy-cyclohexyl-phenyl-ketone. Manufactured by BASF corporation. Product number Irgacure 184.

Photopolymerization initiator C: 4, 4' -bis (diethylamino) benzophenone.

- (C) photopolymerizable Compound

Photopolymerizable compound a: trimethylolpropane triacrylate.

- (D) epoxy resins

Epoxy resin a: bisphenol type crystalline epoxy resin. Manufactured by Nippon iron chemical & materials Co. The product number YSLV-80 XY. The melting point is 75-85 ℃. Epoxy equivalent 192 g/eq.

Solution of epoxy resin B: a bisphenol A epoxy resin having a long carbon chain (product No. EPICLON EXA-4816, liquid resin, epoxy equivalent 410g/eq, manufactured by DIC) was dissolved in diethylene glycol monoethyl ether acetate at a solid content of 90% by mass (epoxy equivalent 455.56g/eq in 90% solid content).

Organic fillers (E)

Dispersion of organic filler a: a dispersion (product No. XER-91-MEK, manufactured by JSR Corp., acid value: 10.0mgKOH/g) obtained by dispersing a crosslinked rubber (NBR) having an average primary particle diameter of 0.07 μm in methyl ethyl ketone so that the content thereof based on the total amount of the dispersion becomes 15% by weight.

- (F) inorganic fillers

Dispersion of inorganic filler a: a dispersion liquid (product No. MEK-EC-2130Y, manufactured by Nissan chemical Co., Ltd.) was prepared by dispersing a silica sol having a particle size of 12nm in methyl ethyl ketone so that the content of the silica sol in the total amount of the dispersion liquid was 30% by mass.

Dispersion of inorganic filler B: a dispersion liquid (product No. MEK-AC-4130Y manufactured by Nissan chemical Co., Ltd.) in which a silica sol having a particle diameter of 45nm was dispersed in methyl ethyl ketone so that the content thereof was 30% by mass based on the total amount of the dispersion liquid.

Additive (G)

Additive A: 3-glycidoxypropyltrimethoxysilane.

Additive B: melamine.

As dilution solvent, the appropriate amount of methyl ethyl ketone is used.

[ Table 1]

(3) Production of test pieces

Using the photosensitive compositions shown in table 2 below, test pieces were produced as follows.

After the photosensitive composition was applied to a film made of polyethylene terephthalate by an applicator, the film was heated at 80 ℃ for 5 minutes and then at 95 ℃ for 20 minutes to be dried, thereby forming dry films having thicknesses of 20 μm, 35 μm, and 60 μm on the film.

A glass epoxy copper-clad laminate (FR-4 type) having a thickness of 17.5 μm and provided with a copper foil was prepared. A comb-shaped electrode having a line width/space width of 50 μm/50 μm as a conductor wiring was formed on the glass epoxy copper-clad laminate by a subtractive method, thereby obtaining a core material. The surface layer portion of the conductor wiring of the core material, which portion is about 1 μm thick, is removed by dissolution with an etchant (organic acid based micro-etching agent manufactured by MEC corporation, product number CZ-8101), thereby roughening the conductor wiring. And laminating the dry film on the whole surface of one surface of the core material by using a vacuum laminating machine. The heat lamination was carried out under conditions of 0.5MPa, 80 ℃ and 1 minute. Thereby, a coating film composed of the dry film is formed on the core material. The film was irradiated with ultraviolet rays through various exposure methods via a negative mask in a state where the negative mask having a non-exposed portion including a circular pattern having a diameter of 50 μm, 70 μm, and 100 μm was directly brought into contact with the film made of polyethylene terephthalate. The exposed coating is subjected to a developing treatment.

In the developing treatment, the coating was sprayed with 1 mass% Na at 30 ℃ under a spray pressure of 0.2MPa₂CO₃The aqueous solution was for 90 seconds. Subsequently, pure water was sprayed to the film at a spray pressure of 0.2MPa for 90 seconds. Thereby, the unexposed portion of the film is removed, and a hole is formed in the film.

After exposure and before development, a film made of polyethylene terephthalate was peeled off from the dry film (coating film).

Next, the film was heated at the temperature and for the time shown in table 2 below. In the examples or reference examples shown below, the post-irradiation step or the pre-irradiation step was performed under the following conditions.

In the post-irradiation step of example 18, a high-pressure mercury lamp was used and the illuminance was 906mW/cm²And an irradiation dose of 2000mJ/cm²The irradiation is performed.

In the pre-irradiation step in example 19, a high-pressure mercury lamp was used, and the illuminance was 12mW/cm²The dose of irradiation was 500mJ/cm²The irradiation is performed.

In the front irradiation step (in the color of 1) of reference example 1, a high-pressure mercury lamp was used and the illuminance was 906mW/cm²The dose of irradiation was 1000mJ/cm²The irradiation is performed. The corresponding sign 1 indicates that the illuminance in the previous irradiation step is out of the range.

In reference example 2, a front irradiation process (, 2) uses a high-pressure mercury lampIlluminance of 906mW/cm²And an irradiation dose of 2000mJ/cm²The irradiation is performed. The corresponding sign 2 indicates that the illuminance in the preceding irradiation step is out of the range.

Thus, test pieces of examples, comparative examples and reference examples were obtained.

(4) Evaluation of

[ evaluation of copper plating adhesion ]

In the test piece obtained above, the outer surface of the layer composed of the cured product was roughened by the following procedure based on a general desmear treatment in the pre-step of the plating treatment. A commercially available Swelling solution (spinning Dip securigant P, manufactured by Atotech Japan) was used as a desmearing Swelling solution to swell the surface of the cured product at 70 ℃ for 15 minutes. Then, the swollen surface was subjected to hot water washing. Next, roughening treatment was performed at 70 ℃ for 10 minutes using an oxidizing agent (concentrated Compact CP manufactured by Atotech Japan) commercially available as a desmear solution containing potassium permanganate, and the surface after hot water washing was roughened. The surface of the cured product thus roughened was washed with hot water, and the residue of the desmear solution on the surface of the cured product was treated with a neutralizing solution (Reduction solution securiganteh P manufactured by Atotech Japan) at 40 ℃ for 5 minutes to remove the residue. Then, the surface of the neutralized cured product is washed with water.

In the test piece subjected to the above roughening treatment, the initial wiring was formed on the rough surface of the test piece by electroless copper plating using a commercially available chemical solution for the layer composed of the cured product. The test piece provided with the initial wiring was heated at 150 ℃ for 1 hour. Next, by electrolytic copper plating treatment, at 2A/dm²Copper having a thickness of 33 μm was deposited directly on the initial wiring from a commercially available chemical solution, and the copper-deposited sample was heated at 180 ℃ for 30 minutes to form a copper-plated layer. The adhesion between the copper plating layer formed in this manner and the cured product of the test piece was evaluated according to the following evaluation criteria.

Here, when no blistering of the test piece was observed during heating both after the electroless copper plating treatment and after the electrolytic copper plating treatment, the adhesion strength between the copper plating layer and the cured product was evaluated by the following procedure. The adhesion strength was measured according to JIS C6481. In order to confirm the adhesion stability of the copper plating layer, 3 tests were performed.

A: no blistering was observed during heating after the electroless copper plating treatment, and no blistering was observed during heating after the electrolytic copper plating treatment. Then, the adhesion strength of copper was determined by averaging the results of 3 tests, and the value was 0.7kN/m or more.

B: no blistering was observed during heating after the electroless copper plating treatment, and no blistering was observed during heating after the electrolytic copper plating treatment. Then, the adhesion strength of copper was determined by averaging the results of 3 tests, and the value was 0.5kN/m or more and less than 0.7 kN/m.

C: no blistering was observed during heating after the electroless copper plating treatment, and no blistering was observed during heating after the electrolytic copper plating treatment. Then, the adhesion strength of copper was determined by averaging the results of 3 tests and was less than 0.5 kN.

D: foaming may be observed during heating after the electroless copper plating treatment or during heating after the electrolytic copper plating treatment.

[ evaluation of insulation reliability ]

The test piece obtained above was exposed to a test environment of 130 ℃ and 85% r.h. for 100 hours while applying a bias of DC30V to the conductor wiring (comb electrode) of the test piece. The resistance value between the comb-shaped electrodes of the layer composed of the cured product in this test environment was continuously measured, and the results thereof were evaluated as follows.

A: the resistance value was maintained at 10 for a period of 100 hours from the start of the test⁶Omega or more.

B: the resistance value was maintained at 10 from the start of the test until 70 hours had passed⁶Omega is not less than 10, but the resistance value is less than 100 hours before the test is started⁶Ω。

C: the resistance value was maintained at 10 from the start of the test to 50 hours after the start⁶Omega is not less than 10, but the resistance value is less than 70 hours before the test is started⁶Ω。

D: from the start of the test to the passage ofThe resistance value is less than 10 hours before 50 hours⁶Ω。

[ evaluation of resolution ]

The opening formed by the layer of the cured product in the test piece obtained above was observed, and the results thereof were evaluated as follows.

A: an opening having a diameter of 50 μm was formed.

B: openings having a diameter of 70 μm were formed, but openings having a diameter of 50 μm were not formed.

C: openings having a diameter of 100 μm were formed, but openings having a diameter of 70 μm were not formed.

D: no opening having a diameter of 100 μm was formed.

[ Table 2]

Fig. 1A is an electron micrograph of the coating after each surface roughening step of example 13, and fig. 1B is an electron micrograph of the coating after each surface roughening step of comparative example 1. It is understood that in the production method of the example, a roughened shape having a high anchoring effect is formed in the film. In the production method of the comparative example, a roughened shape in which an anchoring effect can be obtained cannot be obtained.

(conclusion)

As can be seen from the above, the method for manufacturing an interlayer insulating film according to the first aspect of the present disclosure includes a coating film forming step, an exposure step, and a thermosetting step. In the film forming step, a film of a photosensitive composition containing (a) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photopolymerizable compound, and (D) an epoxy resin is formed. In the exposure step, the amount of the solution was 3mW/cm²～300mW/cm²The film is exposed to ultraviolet light having a wavelength of 320nm to 390 nm. In the thermosetting step, the coating after the exposure step is thermally cured at a temperature of 140 ℃ or higher.

According to the first aspect, the coating can be formed into an appropriate crosslinked structure by exposure to light in a specific range of illuminance in the exposure step, and the coating formed with the appropriate crosslinked structure can be formed into a sea-island structure by heating the coating in a specific range of temperature in the subsequent thermosetting step.

The method of manufacturing an interlayer insulating film according to the second aspect further includes, after the exposure step, a step of alkali-developing the coating after the exposure step (alkali-developing step).

According to the second aspect, the coating can be patterned.

A method for producing an interlayer insulating film according to a third aspect is the first or second aspect, wherein the photosensitive composition further contains (E) an organic filler.

According to the third aspect, thixotropy can be imparted to the photosensitive composition.

The method of manufacturing an interlayer insulating film according to the fourth aspect, wherein the interlayer insulating film is formed on the substrate at a concentration of more than 300mW/cm after the thermosetting step in any one of the first to third aspects²The step of irradiating the coating film after the heat curing step with ultraviolet rays having a wavelength of 320 to 390nm (post-irradiation step).

According to the fourth aspect, by irradiating the coating after the thermosetting step with ultraviolet rays at an illuminance in the above range, the crosslinking structure of the coating can be further optimized, the anchor effect of the roughened shape can be further improved, and as a result, the copper plating adhesion can be further improved.

The method of manufacturing an interlayer insulating film according to the fifth aspect, wherein the interlayer insulating film is further provided at 3mW/cm after the alkali development step and before the thermosetting step in any one of the second to fourth aspects²～300mW/cm²Irradiating the coating film after the alkali development step with ultraviolet rays having a wavelength of 320 to 390nm (pre-irradiation step).

According to the fifth aspect, by irradiating the coating after the alkali development with ultraviolet rays at the illuminance in the above-described range before the thermosetting step, the crosslinking structure of the coating before the thermosetting step can be further moderated, the anchor effect of the roughened shape can be further improved, and as a result, the copper plating adhesion can be further improved.

A method of manufacturing an interlayer insulating film according to a sixth aspect further includes, after the thermosetting step, a step of performing surface roughening treatment (surface roughening step) on the film after the thermosetting step, in any one of the first to fifth aspects.

According to the sixth aspect, the copper plating adhesion can be further improved.

A seventh aspect of the present invention provides the method for manufacturing an interlayer insulating film, wherein, in any one of the first to sixth aspects, the method further comprises a step (plating step) of plating the film after the thermosetting step, after the thermosetting step.

According to the seventh aspect, the plating layer is formed on the roughened coating having a high anchoring effect formed in the surface roughening step, whereby the interlayer insulating film having excellent copper plating adhesion can be obtained.

The interlayer insulating film according to the eighth aspect is obtained by the method for producing an interlayer insulating film according to any one of the first to seventh aspects.

According to the eighth aspect, since the interlayer insulating film is obtained by the above method for manufacturing an interlayer insulating film, the interlayer insulating film has excellent copper plating adhesion.

The interlayer insulating film of the ninth embodiment comprises a photosensitive composition passing 3mW/cm²～300mW/cm²Ultraviolet rays having a wavelength of 320 to 390nm and heat at a temperature of 140 ℃ or higher. The photosensitive composition contains (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photopolymerizable compound, and (D) an epoxy resin.

According to the ninth aspect, the interlayer insulating film has excellent copper plating adhesion.

Claims

1. A method for manufacturing an interlayer insulating film, comprising the steps of:

a step of forming a coating film of a photosensitive composition containing (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photopolymerizable compound, and (D) an epoxy resin,

at 3mW/cm²～300mW/cm²Is 320nm toA step of irradiating ultraviolet rays having a wavelength of 390nm, and

and a step of thermally curing the coating film after the exposure step at a temperature of 140 ℃ or higher.

2. The method for manufacturing an interlayer insulating film according to claim 1, further comprising a step of alkali-developing the coating after said exposure step.

3. The method for producing an interlayer insulating film according to claim 1 or 2, wherein the photosensitive composition further contains (E) an organic filler.

4. The method for manufacturing an interlayer insulating film according to any one of claims 1 to 3, further comprising a step of heating the film at a temperature of more than 300mW/cm after the thermosetting step²Irradiating the coating film after the heat curing step with ultraviolet rays having a wavelength of 320nm to 390 nm.

5. The method for manufacturing an interlayer insulating film according to any one of claims 2 to 4, further comprising a step of forming a film of 3mW/cm after said alkali development step and before said thermosetting step²～300mW/cm²Irradiating the coating film after the alkali development step with ultraviolet rays having a wavelength of 320nm to 390 nm.

6. The method of manufacturing an interlayer insulating film according to any one of claims 1 to 5, further comprising a step of performing surface roughening treatment on the coating after the thermosetting step.

7. The method for manufacturing an interlayer insulating film according to any one of claims 1 to 6, further comprising a step of plating the coating film after the thermosetting step.

8. An interlayer insulating film obtained by the method for producing an interlayer insulating film according to any one of claims 1 to 7.

9. An interlayer insulating film comprising a photosensitive composition passing 3mW/cm²～300mW/cm²Ultraviolet rays having a wavelength of 320 to 390nm and heat at a temperature of 140 ℃ or higher,

the photosensitive composition contains (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photopolymerizable compound, and (D) an epoxy resin.