JP2023149471A - Positive photosensitive dry film, cured product of the same and electronic component - Google Patents

Abstract

To provide a positive photosensitive dry film which closely adheres to a base material at an appropriate heating temperature as a dry film, can be patterned by photolithography, and enables the production of an insulation film with excellent heat characteristics (Tg), a cured product of the same, and an electronic component.SOLUTION: A positive photosensitive dry film includes a resin layer composed of a positive photosensitive resin composition on a support film. The positive photosensitive resin composition contains (A) a polybenzoxazole precursor, (B) a phenol resin, (C) a diazonaphthoquinone derivative, and (D) a compound with two or more methylol and/or methoxy functional groups, wherein (B) the phenol resin has a weight average molecular weight Mw of 600-2,500 and a dispersion degree Mw/Mn of 1.5-3.0, and the content of (B) the phenol resin is 6-50 pts.mass relative to 100 pts.mass of (A) the polybenzoxazole precursor.SELECTED DRAWING: None

Description

The present invention relates to a positive photosensitive dry film (hereinafter also simply referred to as "dry film") useful in electronic components such as semiconductor materials, a cured product thereof, and an electronic component.

A build-up method is known as a method for manufacturing multilayer printed wiring boards, in which insulating layers and conductive layers are alternately stacked on an inner layer circuit board. In multilayer printed wiring boards manufactured using such a build-up method, a thermosetting resin composition containing epoxy resin as the main component is generally used as the insulating layer, and the cured product is coated with a carbon dioxide laser to form an interlayer. A via is formed to provide electrical continuity.

Furthermore, in the build-up method, a dry film type material is used for the insulating layer. Such a dry film type material can form a flat layer by thermocompression bonding to a printed wiring board using a laminator, making it easy to increase the number of layers.

On the other hand, in recent years, in semiconductor packages manufactured using the build-up method, the diameter of the vias has become smaller as the performance has improved, and the number of vias has also been increasing. On the other hand, it is difficult to process vias with small diameters using conventional carbon dioxide lasers, and with UV-YAG lasers, which can form vias with small diameters, the processing speed is slow and manufacturing costs are high.

Therefore, instead of laser processing, forming vias by photolithography is being considered. Among them, polyimide precursors and polybenzene, which are used in the manufacture of semiconductor devices and have excellent thermal properties (high Tg) and resolution, are being considered. Positive type photosensitive resin compositions containing oxazole precursors as a main component are attracting attention.

For example, Patent Documents 1 and 2 describe positive photosensitive resin compositions containing a polybenzoxazole precursor as a main component and containing a photoacid generator and a silane coupling agent.

Re-publication 2018/056013 JP2021-032991A

However, the positive photosensitive resin composition described in the above patent document is liquid because it is spin-coated in the manufacturing process of semiconductor elements, and when processed into a dry film type, it does not adhere tightly to the base material when thermocompression bonded with a laminator. There was a problem of not being able to get enough sex. Therefore, there has been a demand for a positive photosensitive dry film that has the characteristics of the compositions disclosed in Patent Documents 1 and 2 and can be handled as a dry film.

Therefore, the purpose of the present invention is to provide a positive photosensitive dry film that adheres to a substrate at an appropriate heating temperature as a dry film, can be patterned by photolithography, and can provide an insulating film with excellent thermal properties (Tg). The purpose of the present invention is to provide cured products and electronic components thereof.

The present inventors have completed the present invention as a result of intensive studies to solve the above problems.

That is, the positive photosensitive dry film of the present invention is a positive photosensitive dry film comprising a resin layer made of a positive photosensitive resin composition on a support film,
The positive photosensitive resin composition is
(A) a polybenzoxazole precursor;
(B) phenolic resin;
(C) a diazonaphthoquinone derivative;
(D) a compound containing two or more functional methylol groups and/or methoxy groups;
including;
The (B) phenolic resin has a weight average molecular weight Mw of 600 to 2500, a dispersity Mw/Mn (weight average molecular weight/number average molecular weight) of 1.5 to 3.0, and It is characterized in that the content is from 6 parts by mass to 50 parts by mass based on 100 parts by mass of the benzoxazole precursor.

Further, the cured product of the present invention is characterized in that the resin layer contained in the positive photosensitive dry film is cured.

Furthermore, the electronic component of the present invention is characterized by containing the above-mentioned cured product.

According to the present invention, a positive photosensitive dry film that adheres to a substrate at an appropriate heating temperature as a dry film, can be patterned by photolithography, and provides an insulating film with excellent thermal properties (Tg); It has become possible to create cured products and electronic components.

Embodiments of the present invention will be described in detail below.
(Positive photosensitive dry film)
The positive photosensitive dry film of the present invention includes a resin layer made of a positive photosensitive resin composition (hereinafter also simply referred to as "resin composition") on a support film.

First, the components contained in the positive photosensitive resin composition constituting the resin layer of the positive photosensitive dry film of the present invention will be described in detail.

[(A) Polybenzoxazole precursor]
The positive photosensitive resin composition according to the present invention contains (A) a polybenzoxazole precursor. (A) The method for synthesizing the polybenzoxazole precursor is not particularly limited, and any known method may be used. For example, it can be obtained by reacting dihydroxydiamines as an amine component with a dihalide of a dicarboxylic acid such as dicarboxylic acid dichloride as an acid component.

（式中、Ｘは４価の有機基を示し、Ｙは２価の有機基を示し、ｎは１以上の整数であり、好ましくは１０～５０、より好ましくは２０～４０である。） (A) The polybenzoxazole precursor is preferably a polyhydroxyamic acid having a repeating structure represented by the following formula.

(In the formula, X represents a tetravalent organic group, Y represents a divalent organic group, and n is an integer of 1 or more, preferably 10 to 50, more preferably 20 to 40.)

(A) When the polybenzoxazole precursor is synthesized by the above synthesis method, in the above general formula (1), X is a residue of the above dihydroxydiamine, and Y is a residue of the above dicarboxylic acid. .

The above dihydroxydiamines include 3,3'-diamino-4,4'-dihydroxybiphenyl, 4,4'-diamino-3,3'-dihydroxybiphenyl, bis(3-amino-4-hydroxyphenyl)propane, Bis(4-amino-3-hydroxyphenyl)propane, bis(3-amino-4-hydroxyphenyl)sulfone, bis(4-amino-3-hydroxyphenyl)sulfone, 2,2-bis(3-amino-4 -hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-amino-3-hydroxyphenyl)-1,1,1,3,3,3-hexa Examples include fluoropropane. Among these, 2,2-bis(3-amino-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane is preferred as the dihydroxydiamine.

Examples of the dicarboxylic acids include isophthalic acid, terephthalic acid, 5-tert-butyl isophthalic acid, 5-bromoisophthalic acid, 5-fluoroisophthalic acid, 5-chloroisophthalic acid, 2,6-naphthalene dicarboxylic acid, 4,4' -Dicarboxybiphenyl, 4,4'-dicarboxydiphenyl ether, 4,4'-dicarboxytetraphenylsilane, bis(4-carboxyphenyl)sulfone, 2,2-bis(p-carboxyphenyl)propane, 2,2 -Dicarboxylic acids having an aromatic ring such as -bis(4-carboxyphenyl)-1,1,1,3,3,3-hexafluoropropane, oxalic acid, malonic acid, succinic acid, 1,2-cyclobutanedicarboxylic acid, Examples include aliphatic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and 1,3-cyclopentanedicarboxylic acid. Among them, 4,4'-dicarboxydiphenyl ether is preferred.

In the above general formula (1), the tetravalent organic group represented by More preferably, it is located on an aromatic ring. The number of carbon atoms in the tetravalent aromatic group is preferably 6 to 30, more preferably 6 to 24. Specific examples of the above-mentioned tetravalent aromatic group include the following groups, but are not limited to these. Known aromatic groups that can be included in the polybenzoxazole precursor may be selected depending on the purpose. Bye.

Among the aromatic groups described above, the tetravalent aromatic group is preferably the following group.

In the above general formula (1), the divalent organic group represented by Y may be an aliphatic group or an aromatic group, but is preferably an aromatic group, and the carbonyl group in the above general formula (1) is preferably an aromatic group. More preferably, it is combined with. The number of carbon atoms in the divalent aromatic group is preferably 6 to 30, more preferably 6 to 24. Specific examples of the above-mentioned divalent aromatic group include the following groups, but are not limited to these. Known aromatic groups contained in the polybenzoxazole precursor may be selected depending on the purpose. Bye.

（式中、Ａは単結合、－ＣＨ_２－、－Ｏ－、－ＣＯ－、－Ｓ－、－ＳＯ_２－、－ＮＨＣＯ－、－Ｃ（ＣＦ_３）_２－、および、－Ｃ（ＣＨ_３）_２－からなる群から選択される２価の基を表す。）

(In the formula, A is a single bond, -CH ₂ -, -O-, -CO-, -S-, -SO ₂ -, -NHCO-, -C(CF ₃ ) ₂ -, and -C(CH ₃ ) Represents a divalent group selected from the group consisting of ₂ -.)

Among the aromatic groups, the divalent organic group is preferably the following group.

(A) The polybenzoxazole precursor may contain two or more types of repeating structures of the above polyhydroxyamic acid. Further, it may contain a structure other than the repeating structure of polyhydroxyamic acid described above, for example, it may contain a repeating structure of polyamic acid.

The number average molecular weight Mn of the polybenzoxazole precursor (A) is preferably from 5,000 to 100,000, more preferably from 8,000 to 50,000. Here, in the present invention, the number average molecular weight Mn is a value measured by gel permeation chromatography (GPC) and converted to standard polystyrene. Further, the weight average molecular weight Mw of the polybenzoxazole precursor (A) is preferably 10,000 to 200,000, more preferably 16,000 to 100,000. Here, in the present invention, the weight average molecular weight Mw is a value measured by GPC and converted using standard polystyrene. Further, the degree of dispersion Mw/Mn of the polybenzoxazole precursor (A) is preferably from 1 to 5, more preferably from 1 to 3.

(A) The polybenzoxazole precursors may be used alone or in combination of two or more. (A) The blending amount of the polybenzoxazole precursor is preferably 50% by mass to 90% by mass based on the total solid content of the resin composition.

[(B) Phenol resin]
The positive photosensitive resin composition according to the present invention contains (B) a phenol resin. (B) The phenol resin is not particularly limited, and for example, phenol novolak resin, cresol novolak resin, dicyclopentadiene type phenol resin, trisphenolmethane type phenol resin, etc. can be used. In particular, it is preferable to use a phenol novolak resin or cresol novolak resin that has a phenolic hydroxyl equivalent of 95 to 120 g/eq and a softening point between 75°C and 125°C. According to Dry Film, sufficient adhesion to the substrate can be obtained by thermocompression bonding with a laminator, and it can also improve the development resistance of unexposed areas in photolithography, and has excellent heat resistance. A cured product can be obtained.

The weight average molecular weight Mw of the phenol resin (B) needs to be 600 to 2,500, preferably 600 to 1,500. Further, the dispersity Mw/Mn of the phenol resin (B) needs to be 1.5 to 3.0, preferably 1.8 to 2.1. By using the phenol resin (B) having such a weight average molecular weight Mw and dispersity Mw/Mn, development defects in exposed areas can be suppressed in photolithography, and development resistance of unexposed areas can be improved. .

The blending amount of (B) phenol resin is required to be 6 parts by mass to 50 parts by mass, and is 15 parts by mass to 40 parts by mass, based on 100 parts by mass of (A) polybenzoxazole precursor. It is preferable. (B) If the blending amount of the phenol resin is too small, sufficient adhesion to the substrate will not be obtained when formed into a film, and turbidity will occur on the film surface during development. (B) If the blending amount of the phenol resin is too large, the thermal properties (Tg) of the insulating film will deteriorate, and the surface of the pattern (unexposed) portion will become cloudy during development.

[(C) Diazonaphthoquinone derivative]
The positive photosensitive resin composition according to the present invention contains (C) a diazonaphthoquinone derivative. (C) The diazonaphthoquinone derivative is not particularly limited, and includes, for example, a naphthoquinonediazide adduct of tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene (for example, TKF-428 manufactured by Sanpo Chemical Research Institute), TKF-528, TS533, TS567, TS583, TS593) and naphthoquinonediazide adducts of tetrahydroxybenzophenone (for example, BS550, BS570, BS599 manufactured by Sanpo Chemical Research Institute).

By using (A) polybenzoxazole precursor and (B) phenol resin in combination with (C) diazonaphthoquinone derivative, which is known as a positive photosensitive material, it is possible to impart low alkali solubility to the non-light irradiated area. , patterning by photolithography becomes possible.

(C) Diazonaphthoquinone derivatives may be used alone or in combination of two or more. The blending amount of the diazonaphthoquinone derivative (C) is preferably 5 parts by mass to 15 parts by mass based on 100 parts by mass of the polybenzoxazole precursor (A). By setting the blending amount of the diazonaphthoquinone derivative (C) within the above range, the effects of blending the diazonaphthoquinone derivative (C) can be favorably obtained.

[(D) Compound containing two or more functional methylol groups and/or methoxy groups]
The positive photosensitive resin composition according to the present invention contains (D) a compound containing two or more functional methylol groups and/or methoxy groups. (D) The compound containing two or more functional methylol groups and/or methoxy groups is not particularly limited, and examples thereof include compounds represented by the following structural formula. Among these, it is preferable to use a melamine derivative containing two or more functional methoxy groups.

In addition to (A) a polybenzoxazole precursor that exhibits high heat resistance when ring-closed by heating, (B) a phenol resin, and (D) a compound containing two or more functional groups of methylol and/or methoxy groups was used. A crosslinked structure is formed by these, and an insulating film having high heat resistance (high Tg) can be realized.

(D) Compounds containing two or more functional methylol groups and/or methoxy groups may be used alone or in combination of two or more. (D) The compounding amount of the compound containing two or more functional methylol groups and/or methoxy groups is preferably 10 parts by mass to 30 parts by mass based on 100 parts by mass of (A) polybenzoxazole precursor. (D) By setting the blending amount of the compound containing two or more functional groups of methylol group and/or methoxy group within the above range, the effect of blending the compound containing (D) two or more functional groups of methylol group and/or methoxy group can be improved. can be obtained.

[Other ingredients]
The positive photosensitive resin composition according to the present invention may optionally contain other components in addition to the components (A) to (D) above.

The positive photosensitive resin composition according to the present invention preferably contains (E) t-butylcatechol. (E) By containing t-butylcatechol, there is little development residue (scum) in the exposed area, and the developability can be excellent. The blending amount of (E) t-butylcatechol is preferably 0.1 parts by mass to 1.0 parts by mass based on 100 parts by mass of (A) polybenzoxazole precursor.

The positive photosensitive resin composition according to the present invention may contain various other organic or inorganic low-molecular or high-molecular compounds in order to impart processing properties and various functionalities. For example, surfactants, (F) leveling agents, plasticizers, fine particles, etc. can be used. Among these, the fine particles include organic fine particles such as polystyrene and polytetrafluoroethylene, and inorganic fine particles such as colloidal silica, carbon, and layered silicates. Furthermore, as the leveling agent (surface conditioning agent) (F), a non-silicon release agent such as a thermoplastic acrylic resin can be used.

Furthermore, a known sensitizer can be added to the positive photosensitive resin composition according to the present invention in order to improve photosensitivity. Furthermore, a known adhesion aid may be added to the positive photosensitive resin composition according to the present invention in order to improve adhesion to a substrate. Furthermore, various coloring agents, fibers, etc. may be added to the positive photosensitive resin composition according to the present invention.

(G) a solvent (solvent) can be blended into the positive photosensitive resin composition according to the present invention. As a solvent, (A) polybenzoxazole precursor, (B) phenol resin, (C) diazonaphthoquinone derivative, (D) compound containing two or more functional groups of methylol group and/or methoxy group, and other components are dissolved. There is no particular limitation as long as it is possible. (G) Solvents include, for example, N,N'-dimethylformamide, N-methylpyrrolidone, N-ethyl-2-pyrrolidone, N,N'-dimethylacetamide, diethylene glycol dimethyl ether, cyclopentanone, γ -butyrolactone, α-acetyl-γ-butyrolactone, tetramethylurea, 1,3-dimethyl-2-imidazolinone, N-cyclohexyl-2-pyrrolidone, dimethyl sulfoxide, hexamethylphosphoramide, pyridine, diethylene glycol monomethyl ether be able to.

(G) The solvent may be used alone or in combination of two or more. The amount of the solvent (G) to be used can range from 50 to 9,000 parts by mass based on 100 parts by mass of the polybenzoxazole precursor (A), depending on the coating film thickness and viscosity. Moreover, the (G) solvent may be contained in the resin layer of the dry film of the present invention in an amount of 20% by mass or less.

The positive photosensitive dry film of the present invention has a resin layer obtained by coating the above positive photosensitive resin composition on a support film and then drying it. The dry film of the present invention is used by laminating the resin layer so as to be in contact with the base material.

The dry film of the present invention is produced by uniformly applying the above-mentioned positive photosensitive resin composition onto a support film (carrier film) using an appropriate method such as a blade coater, lip coater, comma coater, or film coater, and then drying it. It can be manufactured by forming a resin layer and preferably laminating a protective film (cover film) thereon. The drying method is not particularly limited, and methods such as air drying, heating drying using an oven or hot plate, and vacuum drying are used. Further, it is desirable that the drying be carried out under conditions such that ring closure of the polybenzoxazole precursor (A) in the resin layer does not occur. Specifically, for example, natural drying, blow drying, or heat drying can be performed at 70 to 110° C. for 1 to 30 minutes. Preferably, drying is carried out in an oven for 1 to 20 minutes. Vacuum drying is also possible, and in this case it can be carried out at room temperature for 20 minutes to 1 hour.

In the dry film of the present invention, any materials known for use in dry films can be used for the support film and the protective film. The support film and the protective film may be made of the same material or may be made of different materials. As the support film, for example, a thermoplastic resin film such as a polyester film such as polyethylene terephthalate having a thickness of 2 to 150 μm is used. As the protective film, polyethylene film, polypropylene film, etc. can be used, but it is preferable that the adhesive strength to the resin layer is smaller than that of the support film.

In the present invention, a resin layer may be formed by coating and drying the positive photosensitive resin composition on the protective film, and a support film may be laminated on the surface of the resin layer. That is, in the present invention, as the film to which the resin composition is applied when manufacturing the dry film, either a support film or a protective film may be used.

The thickness of the resin layer on the dry film of the present invention is preferably 40 μm or less, more preferably in the range of 5 μm to 25 μm.

(cured product)
The cured product of the present invention is obtained by curing the resin layer contained in the dry film of the present invention, and becomes an insulating film with excellent thermal properties (Tg). A patterned cured product can be obtained by the following manufacturing method.

First, in step 1, the positive photosensitive dry film of the present invention is laminated onto a base material using a laminator or the like so that the resin layer is in contact with the base material, and then the supporting film is peeled off. Form a resin layer.

The above-mentioned base materials include printed wiring boards and flexible printed wiring boards on which circuits are previously formed using copper, etc., as well as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth/nonwoven epoxy, and glass cloth/paper epoxy. , synthetic fiber epoxy, fluororesin/polyethylene/polyphenylene ether, polyphenylene oxide/cyanate, etc., are used in copper-clad laminates for high-frequency circuits, and all grades (FR-4, etc.) of copper-clad laminates are used. Other examples include metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates, and the like.

Next, in step 2, the resin film is exposed to light through a photomask having a predetermined pattern or directly. The exposure light beam used has a wavelength that can activate the diazonaphthoquinone derivative (C) and generate acid. Specifically, the exposure light preferably has a maximum wavelength in the range of 350 to 410 nm. As described above, photosensitivity can be adjusted by appropriately using a sensitizer. As the exposure device, a contact aligner, mirror projection, stepper, laser direct exposure device, etc. can be used.

Next, in step 3, heating may be performed to close a part of the polybenzoxazole precursor (A) in the unexposed area. Here, the ring closure rate can be about 30%, for example, 10% or more and 40% or less. The heating time and heating temperature are changed as appropriate depending on the type of polybenzoxazole precursor (A) and the coating film thickness.

Next, in step 4, the resin film is treated with a developer. Thereby, the exposed portion in the resin film can be removed to form a pattern film of the resin layer of the positive photosensitive dry film of the present invention.

As the method used for development, any method can be selected from conventionally known photoresist development methods, such as a rotary spray method, a paddle method, and an immersion method accompanied by ultrasonic treatment. Examples of developing solutions include inorganic alkalis such as sodium hydroxide, sodium carbonate, sodium silicate, and aqueous ammonia, organic amines such as ethylamine, diethylamine, triethylamine, and triethanolamine, and tetramethylammonium hydroxide and tetrabutylammonium hydroxide. Examples include aqueous solutions of quaternary ammonium salts such as . Further, if necessary, an appropriate amount of a water-soluble organic solvent such as methanol, ethanol, isopropyl alcohol, or a surfactant may be added to these. Thereafter, if necessary, the resin film is washed with a rinsing liquid to obtain a pattern film. As the rinsing liquid, distilled water, methanol, ethanol, isopropyl alcohol, etc. can be used alone or in combination. Further, the above-mentioned solvents may be used as the developer.

Thereafter, in step 5, the patterned film is heated to obtain a cured coating film (cured product). At this time, polybenzoxazole may be obtained by ring-closing the polybenzoxazole precursor (A). The heating temperature is appropriately set within a range that can cure the polybenzoxazole pattern film. For example, heating is performed at 150 to 350° C. for about 5 to 120 minutes in an inert gas. A more preferable heating temperature range is 180 to 300°C. Heating is performed, for example, by using a hot plate, an oven, or a heating oven in which a temperature program can be set. As the atmosphere (gas) at this time, air may be used, or an inert gas such as nitrogen or argon may be used.

The use of the dry film of the present invention is not particularly limited, and includes, for example, adhesives, fillers, electronic materials, optical circuit components, molding materials, resist materials, building materials, three-dimensional modeling, optical components, and other known fields and products. Examples include. The dry film of the present invention is particularly useful in a wide range of fields and products where the properties such as heat resistance, dimensional stability, and insulation properties of polybenzoxazole films are effective, such as color filters, flexible display films, and semiconductor devices. It is suitably used as a forming material for coating films, electronic components, interlayer insulating films, coating films for printed wiring boards such as solder resists, optical circuits, optical circuit components, antireflection films, holograms, optical members, or building materials.

In particular, the dry film of the present invention is mainly used as a pattern forming material (resist), and the pattern film formed thereby functions as a component that provides heat resistance and insulation as a permanent film made of polybenzoxazole. For example, color filters, flexible display films, electronic components, coating films for semiconductor elements, interlayer insulation films, coating films for printed wiring boards such as solder resists and coverlay films, solder dams, optical circuits, optical circuit components, It is suitable for forming antireflection films, other optical members, or electronic members.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited by these Examples and Comparative Examples. In addition, all "parts" and "%" below are based on mass unless otherwise specified.

(Synthesis of polybenzoxazole (PBO) precursor)
212 g of N-methylpyrrolidone was charged into a 0.5 L flask equipped with a stirrer and a thermometer, and 28.00 g (76.5 mmol) of bis(3-amino-4-hydroxyamidophenyl)hexafluoropropane was dissolved with stirring. Thereafter, the flask was immersed in an ice bath, and while keeping the inside of the flask at 0 to 5°C, 25.00 g (83.2 mmol) of 4,4-diphenyl ether dicarboxylic acid chloride was added as a solid in 5 g portions over 30 minutes. The mixture was stirred for 30 minutes. Thereafter, stirring was continued for 5 hours at room temperature. The stirred solution was poured into 1 L of ion-exchanged water (specific resistance value: 18.2 MΩ·cm), and the precipitate was collected. Thereafter, the obtained solid was dissolved in 420 mL of acetone and poured into 1 L of ion-exchanged water. After collecting the precipitated solid, it was dried under reduced pressure to obtain a polybenzoxazole (PBO) precursor A1 having carboxyl group terminals and the following repeating structure. The number average molecular weight (Mn) of the polybenzoxazole precursor A1 was 12,900, the weight average molecular weight (Mw) was 29,300, and the Mw/Mn was 2.28.

Varnishes of positive photosensitive resin compositions of Examples and Comparative Examples were prepared according to the formulations shown in the table below. (A) As the PBO precursor, the benzoxazole precursor synthesized above was used.

The amount of solvent was adjusted so that the viscosity of this positive photosensitive resin composition was 0.5 to 20 dPa·s (rotational viscometer 5 rpm, 25°C), and the thickness of the resin layer was adjusted using a bar coater. It was coated on a support film (polyethylene terephthalate (PET) film; TN-200 manufactured by Toyobo Co., Ltd., thickness 38 μm, size 30 cm x 30 cm) so that the film had a thickness of 15 μm after drying. Next, the resin layer was dried in a hot air circulation drying oven at 70 to 90°C (average 80°C) for 10 to 20 minutes so that the residual solvent in the resin layer was 0.5 to 17.5% by mass. A resin layer was formed to produce a positive photosensitive dry film.

[Development speed evaluation]
(1) A resin layer of a dry film was laminated onto a Si wafer using a vacuum laminator (CVP-600, manufactured by Nikko Materials, chamber temperature: 90° C.) to prepare a film for evaluation.
(2) A part of the obtained evaluation film was exposed to light at an exposure dose of 500 mJ/cm ² .
(3) The exposed evaluation film and the unexposed evaluation film were immersed in a 1 wt % NaOH aqueous solution for 20 seconds and developed while being vibrated.
(4) Determine the development speed per second [nm/s] from the film thickness before and after development, calculate the dissolution rate ratio (development speed of unexposed area/development speed of exposed area), and evaluate according to the following evaluation criteria. went.

(Evaluation criteria)
○: When the dissolution rate ratio is 2.5 or more.
Δ: When the dissolution rate ratio is 2 or more and less than 2.5.
×: When the dissolution rate ratio is less than 2.

[Lamination adhesion evaluation]
(1) An evaluation sample was prepared by laminating a resin layer of a dry film on a copper-clad laminate whose surface had been treated with an aqueous phosphoric acid solution in the same manner as in the development speed evaluation.
(2) After standing for 1 hour, the support film (PET film) was gently peeled off from the evaluation sample.
(3) The amount of the resin layer remaining on the PET film was evaluated based on the area ratio, and the evaluation was performed according to the following evaluation criteria.

(Evaluation criteria)
◎: When the amount of film remaining on the PET film is 0%.
○: When the amount of film remaining on the PET film is 1% to 10%.
Δ: When the amount of film remaining on the PET film is 11% to 20%.
×: When the amount of film remaining on the PET film is 21% or more.

[Patternability evaluation]
(1) A resin layer of a dry film was laminated onto a 6-inch Si wafer in the same manner as in the development speed evaluation to prepare a film for evaluation.
(2) After standing still for 1 hour, the support film (PET film) was gently peeled off from the evaluation membrane.
(3) The obtained evaluation film was subjected to pattern exposure using a contact exposure machine at an exposure dose of 500 mJ/cm ² .
(4) Evaluation after exposure The film was immersed in a 1 wt % NaOH aqueous solution until the film thickness at the exposed area became 0 μm, and the pattern was developed.
(5) The obtained pattern was observed using a scanning electron microscope (SEM) and evaluated according to the following evaluation criteria.

(Evaluation criteria)
◎◎: When it is possible to form lines of 6 μm or more and less than 10 μm and vias of 6 μm or more and less than 10 μm.
◎: When both lines of 10 μm or more and less than 20 μm and vias of 10 μm or more and less than 20 μm can be formed.
○: When either a line of 10 μm or more and less than 20 μm or a via Φ of 10 μm or more and less than 20 μm can be formed.
Δ: When only lines or vias of 20 μm or more can be formed.
×: When the pattern cannot be observed (contrast is insufficient or the film is peeled off from the Si wafer).

[Thermal property evaluation]
(1) A varnish of a positive photosensitive resin composition was applied onto copper foil with a gap of 150 to 200 μm.
(2) The obtained coating film was dried at 80° C. for 20 minutes.
(3) The dried coating film is heated to 150°C in 10 minutes in the air, held at 150°C for 30 minutes, then heated to 220°C in 14 minutes, and held at 220°C for 1 hour. This made it harden.
(4) The obtained cured film was peeled off from the copper foil, the glass transition temperature Tg was measured by TMA measurement, and evaluation was performed according to the following evaluation criteria.

(Evaluation criteria)
○: When the glass transition temperature Tg (°C) is 200°C or higher.
×: When the glass transition temperature Tg (°C) is less than 200°C.

[Evaluation of film turbidity during development]
(1) A resin layer of a dry film was laminated onto a 6-inch Si wafer in the same manner as in the development speed evaluation to prepare a film for evaluation.
(2) After standing still for 1 hour, the support film (PET film) was gently peeled off from the evaluation membrane.
(3) The obtained evaluation membrane was immersed in a 1 wt% NaOH aqueous solution for 60 seconds.
(4) Evaluation of the membrane after immersion The turbidity of the membrane surface was visually observed and evaluated according to the following evaluation criteria.

(Evaluation criteria)
○: When no turbidity is observed.
×: When turbidity is observed.

[Swelling evaluation during development]
(1) A resin layer of a dry film was laminated onto a 6-inch Si wafer in the same manner as in the development speed evaluation to prepare a film for evaluation.
(2) After standing still for 1 hour, the support film (PET film) was gently peeled off from the evaluation membrane.
(3) The obtained evaluation membrane was immersed in a 1 wt% NaOH aqueous solution for 60 seconds.
(4) The evaluation membrane after immersion was washed with ion-exchanged water, and water was removed using an air blower.
(5) When using an air blower, changes in membrane shape were visually observed and evaluated according to the following evaluation criteria.

(Evaluation criteria)
○: No change was observed in the membrane shape and it was determined that there was no swelling.
×: When a change in the membrane shape is observed and it is determined that the membrane is swollen.

These results are also shown in the table below.

＊１１）ＢＹＫ Ａｄｄｉｔｉｖｅｓ ＆ Ｉｎｓｔｒｕｍｅｎｔｓ社製 表面調整剤 *1) Manufactured by DIC Corporation, phenol novolac resin, hydroxyl equivalent: approximately 104 g/eq. , softening point about 80°C, Mw/Mn=2.08, Mw=1,200
*2) Manufactured by DIC Corporation, phenol novolac resin, hydroxyl equivalent: approximately 105 g/eq. , softening point about 120°C, Mw/Mn=7.87, Mw=10,418
*3) Manufactured by DIC Corporation, cresol novolak resin, hydroxyl equivalent: approximately 117 g/eq. , softening point about 85°C, Mw/Mn=1.86, Mw=850
*4) Manufactured by DIC Corporation, cresol novolac resin, hydroxyl equivalent: approximately 119 g/eq. , softening point about 124°C, Mw/Mn=2.16, Mw=2,300
*5) Manufactured by Meiwa Kasei Co., Ltd., phenol novolak resin, hydroxyl equivalent: approximately 106 g/eq. , Softening point: about 84°C, Mw/Mn=1.31, Mw=1,900
*6) Manufactured by JFE Chemical Co., Ltd., trisphenolmethane resin, hydroxyl equivalent: approximately 203 g/eq. , softening point about 70°C, Mw/Mn=1.33, Mw=541
*7) Manufactured by DIC Corporation, naphthalene type epoxy resin, functional group equivalent: approximately 165 g/eq. , softening point about 90°C, Mw/Mn=1.69, Mw=865
*8) Manufactured by Sanpo Chemical Research Institute, naphthoquinone diazide compound, produced carboxyl group equivalent: approximately 383 g/eq
*9) Sanwa Chemical Co., Ltd., Nikalac MW-390, hexamethoxymethylmelamine *10) DIC Corporation, 4-t-butylcatechol

*11) BYK Additives & Instruments surface conditioning agent

From the results shown in the table above, it is clear that (A) a polybenzoxazole precursor, (B) a phenol resin, (C) a diazonaphthoquinone derivative, and (D) a compound containing two or more functional methylol groups and/or methoxy groups. The positive photosensitive dry film of the present invention, in which (B) a phenolic resin satisfies predetermined physical properties and content, can be patterned by photolithography and is softened by an appropriate heating temperature when formed into a film. It is clear that an insulating film can be obtained which exhibits good properties and adhesion to the substrate, has an appropriate development rate, and has excellent thermal properties (Tg).

Claims (3)

A positive photosensitive dry film comprising a resin layer made of a positive photosensitive resin composition on a support film,
The positive photosensitive resin composition is
(A) a polybenzoxazole precursor;
(B) phenolic resin;
(C) a diazonaphthoquinone derivative;
(D) a compound containing two or more functional methylol groups and/or methoxy groups;
including;
The weight average molecular weight Mw of the (B) phenol resin is 600 to 2500, the dispersity Mw/Mn is 1.5 to 3.0, and the content is based on 100 parts by mass of the polybenzoxazole precursor (A). A positive photosensitive dry film characterized in that the amount is 6 parts by mass to 50 parts by mass. A cured product, characterized in that the resin layer contained in the positive photosensitive dry film according to claim 1 is cured. An electronic component comprising the cured product according to claim 2.