JP7845833B2 - Photosensitive resin laminate - Google Patents

Description

This invention relates to photosensitive resin laminates, photosensitive resin laminate rolls, dry film resists, photosensitive elements, resist pattern formation methods, and the like.

Traditionally, the manufacturing of printed circuit boards and precision metal processing have been carried out using photolithography. The photosensitive resin compositions used in photolithography are classified into negative-type compositions, which dissolve and remove unexposed areas, and positive-type compositions, which dissolve and remove exposed areas.

When applying a photosensitive resin composition onto a substrate in photolithography,
Either (1) a method of applying a photoresist solution to a substrate and drying it, or (2) a method of laminating a photosensitive resin layer onto a substrate using a photosensitive resin laminate in which a layer containing a support and a photosensitive resin composition (hereinafter also referred to as the "photosensitive resin layer") and, if necessary, a cover film are sequentially laminated. In the manufacture of printed circuit boards, the latter method is often used.

Conventionally, technologies relating to the above-mentioned photosensitive resin laminate have been reported (Patent Document 1). A method for forming a pattern using the above-mentioned photosensitive resin laminate is briefly described below. First, the cover film is peeled off the photosensitive resin laminate. Next, using a laminator, the photosensitive resin layer and support are laminated onto a substrate such as a copper-clad laminate or a copper sputtered thin film in the order of substrate, photosensitive resin layer, and support. Then, the photosensitive resin layer is exposed through a photomask having the desired wiring pattern. Next, the support is peeled off from the exposed laminate, and the non-patterned areas are dissolved or dispersed and removed with a developer to form a resist pattern on the substrate.

Japanese Patent Publication No. 2012-220837

Easily peelable polyethylene terephthalate (PET), a typical cover film, has the advantage of being easily peelable from the photosensitive resin layer (low tackiness) due to silicone coatings, etc. On the other hand, easily peelable PET can sometimes experience a deterioration in resolution due to the transfer of silicone or non-silicone components, which act as release agents, from the easily peelable PET to the surface of the photosensitive resin layer.

In the past, both the tackiness of the photosensitive resin layer to the support and the tackiness of the cover film were collectively referred to as "tackiness." However, in this disclosure, "tackiness" refers specifically to the tackiness of the photosensitive resin layer to the cover film.

Furthermore, biaxially oriented polypropylene (OPP), a typical cover film, is also known to tend to have reduced resolution due to the influence of components derived from its raw materials.

Furthermore, while using low-density polyethylene (LDPE) as the cover film makes it easier to achieve good resolution, it also has the disadvantage of tending to have high tackiness with the photosensitive resin layer.

In recent years, with the increasing resolution of resists, the lower molecular weight of binder polymers or the increase in monomer components has led to increased adhesion (tackiness) between the resist and the cover film. This can cause the resist to stick to the cover film during use, separating from the intended support or substrate.

In view of the above circumstances, the present invention aims to provide a photosensitive resin laminate capable of achieving both low tack and high resolution, as well as a roll, resist pattern, and structure using the same.

As a result of diligent research, the inventors focused on the use of LDPE as a cover film for a photosensitive resin laminate. They discovered that by achieving low tack on the photosensitive resin layer side, and by using a specific silicone compound to improve the dispersibility of silicon (Si)-containing components, they could achieve both low tack and high resolution, thereby solving the above-mentioned problems.

One aspect of the present invention is illustrated below.
(1)
A photosensitive laminate comprising a support, a photosensitive resin layer, and a cover film,
The photosensitive resin layer and the cover film are in contact with each other.
The cover film is low-density polyethylene, and the photosensitive resin layer has the following components:
(A) Alkali-soluble resin (B) Photopolymerizable compound having an ethylenically unsaturated bond,
A photosensitive resin laminate characterized by containing (C) a photopolymerization initiator and (D) a double-ended modified silicone compound, wherein the double-ended modified silicone compound is modified by carbinol modification, phenol modification, or silanol modification.
(2)
The photosensitive resin laminate according to item 1, wherein the alkali-soluble resin (A) contains constituent units derived from either acrylic acid or methacrylic acid, or both.
(3)
The photosensitive resin laminate according to item 1 or 2, wherein the (B) photopolymerizable compound having an ethylenically unsaturated bond includes a difunctional monomer and a trifunctional or polyfunctional monomer.
(4)
The photosensitive resin laminate according to any one of items 1 to 3, wherein the functional group equivalent of the (D) end-modified silicone compound is 100 to 1500 g/mol.
(5)
The photosensitive resin laminate according to any one of items 1 to 4, wherein the weight-average molecular weight of the alkali-soluble resin (A) is less than 55,000.
(6)
A photosensitive resin laminate according to any one of items 1 to 5, wherein the weight-average molecular weight of at least one of the alkali-soluble resins (A) is less than 20,000.
(7)
A photosensitive resin laminate according to any one of items 1 to 6, wherein the mass ratio (A)/(B) of the alkali-soluble resin to the photopolymerizable compound having an ethylenically unsaturated bond (B) is less than 1.0.
(8)
A photosensitive resin laminate according to any one of items 1 to 7, wherein the silicone component derived from the end-(D) modified silicone compound is dispersed in the photosensitive resin layer.
(9)
The photosensitive resin laminate according to any one of items 1 to 8, wherein the (D) double-ended modified silicone compound comprises a double-ended modified silicone compound modified by any of the following: double-ended carbinol modification, double-ended phenol modification, or double-ended silanol modification.
(10)
A photosensitive resin laminate according to any one of items 1 to 9, wherein the difference between the surface free energy of the cover film surface in contact with the photosensitive resin layer and the surface free energy of the photosensitive resin layer surface in contact with the cover film is 20 mJ/ ^m² or more.
(11)
The (A) alkali-soluble resin is a photosensitive resin laminate according to any one of items 1 to 10, comprising constituent units derived from aromatic monomer components or alicyclic monomers.
(12)
The photosensitive resin laminate according to any one of items 1 to 11, wherein the thickness of the photosensitive resin layer is 10 μm or less.
(13)
The photosensitive resin laminate according to any one of items 1 to 12, wherein the surface roughness Rz of the cover film on the photosensitive resin layer side is 200 < Rz < 800.
(14)
A roll formed by winding a photosensitive resin laminate as described in any one of items 1 to 13.
(15)
The following steps:
A step of peeling the cover film from the photosensitive resin laminate described in any one of items 1 to 13;
A lamination step in which the surface of the photosensitive resin layer from which the cover film has been peeled off is laminated onto a substrate to form a photosensitive element;
An exposure step of exposing the photosensitive resin layer of the photosensitive element; and a developing step of developing and removing the unexposed portion of the photosensitive resin layer;
A method for forming a resist pattern, including [a specific component].
(16)
The photosensitive resin layer from which the cover film has been peeled off, as described in any one of items 1 to 13,
A substrate laminated from the surface from which the cover film of the photosensitive resin layer has been peeled off,
A structure that includes this.

According to the present invention, it is possible to provide a photosensitive resin laminate that can achieve both low tack and high resolution, as well as a roll, resist pattern, and structure using the same.

The following describes in detail embodiments for carrying out the present invention (hereinafter abbreviated as "embodiments"). However, the present invention is not limited to the following embodiments and can be implemented in various modifications within the scope of its essence.

Furthermore, in this specification, "(meth)acrylic" means acrylic or methacrylic, "(meth)acryloyl" means acryloyl or methacryloyl, and "(meth)acrylate" means acrylate or methacrylate.

<Photosensitive resin laminate>
The photosensitive resin laminate according to this embodiment includes a support, a photosensitive resin layer, and a cover film, wherein the photosensitive resin layer and the cover film are in contact, the cover film is low-density polyethylene, and the photosensitive resin layer has the following components:
(A) Alkali-soluble resin (B) Photopolymerizable compound having an ethylenically unsaturated bond,
(C) A photopolymerization initiator, and (D) a double-ended modified silicone compound, characterized in that it contains a double-ended modified silicone compound modified by carbinol modification, phenol modification, or silanol modification.

The photosensitive resin laminate according to this embodiment is characterized by the above-described configuration, enabling both low tack and high resolution in the formation of rolls, resist patterns, photosensitive elements, and structures.

From the viewpoint of significantly demonstrating the effects of the present invention, the difference between the surface free energy of the cover film surface in contact with the photosensitive resin layer and the surface free energy of the photosensitive resin layer surface in contact with the cover film is preferably 20 mJ/ ^m² or more, more preferably 22 mJ/ ^m² or more, and even more preferably 25 mJ/ ^m² or more.

From the viewpoint of significantly achieving the effects of the present invention, the photosensitive resin laminate is preferably used as a roll formed by winding the photosensitive resin laminate, as a dry film resist, or as a transfer film.

The following describes the various components of the photosensitive resin laminate.

[Photosensitive resin layer]
The photosensitive resin layer of this disclosure is in contact with, preferably in abutment with, a cover film, and comprises the following components:
(A) Alkali-soluble resin (B) Photopolymerizable compound having an ethylenically unsaturated bond,
(C) A photopolymerization initiator, and (D) a double-ended modified silicone compound, which contains a double-ended modified silicone compound modified by carbinol modification, phenol modification, or silanol modification.

Even when the photosensitive resin layer is in contact with the cover film, the inclusion of the above components (A) to (D) allows for low tack between the photosensitive resin layer and the cover film.

The thickness of the photosensitive resin layer in a photosensitive resin laminate is preferably 10 μm or less, more preferably 0.5 μm to 10 μm, and even more preferably 1 μm to 10 μm, from the viewpoint of resist pattern resolution, side etching amount, puncture strength, or low tackiness.

The photosensitive resin layer may contain a photosensitive resin composition comprising the above components (A) to (D), or may consist of a photosensitive resin composition. Optionally, the photosensitive resin layer may contain components other than those listed above (A) to (D). The components of the photosensitive resin layer are described below.

(A) Alkali-soluble resin (A) is a polymer that can dissolve in an alkaline solution. Furthermore, (A) the alkali-soluble resin preferably has carboxyl groups, more preferably has an acid equivalent of 100 to 600, and is even more preferably a copolymer containing a carboxyl group-containing monomer as a copolymer component. Furthermore, (A) the alkali-soluble resin can be thermoplastic.

(A) The acid equivalent of the alkali-soluble resin is preferably 100 or more from the viewpoint of development resistance of the photosensitive resin layer and resolution and adhesion of the resist pattern, while it is preferably 600 or less from the viewpoint of developability and peelability of the photosensitive resin layer. Furthermore, the acid equivalent of (A) the alkali-soluble resin is more preferably 200 to 500, and even more preferably 250 to 450. In one embodiment of the present invention, the acid equivalent refers to the mass (grams) of a polymer having 1 equivalent of carboxyl groups in its molecule, and can be measured, for example, by potentiometric titration using an automatic titrator and a 0.1 mol/L aqueous sodium hydroxide solution.

(A) Alkali-soluble resins are given by the following formula (I):
{In the formula, _Wi is the mass of each comonomer constituting the alkali-soluble resin,
Tg _i is the glass transition temperature when each of the comonomers constituting the alkali-soluble resin is a homopolymer.
W _total is the total mass of the alkali-soluble resin, and n is the number of different types of comonomers that make up the alkali-soluble resin.
It is preferable that the glass transition temperature (Tg _total ) determined by the method is 100°C or less. (A) When a mixture of multiple polymers is used as the alkali-soluble resin, the glass transition temperature is determined as the average value of all polymers.

When determining the glass transition temperature Tg _i , the value shown in "Polymer Handbook, Third Edition, John Wiley & Sons, 1989, p. 209, Chapter VI, 'Glass transition temperatures of polymers'" edited by Brandrup, J. Immergut, E. H. shall be used as the glass transition temperature of the homopolymer composed of the comonomers that form the corresponding alkali-soluble resin.

The Tg _i values for typical comonomers are as follows (all are literature values).
Methacrylic acid: Tg = 501K
Benzyl methacrylate: Tg = 327K
Methyl methacrylate: Tg = 378K
Styrene: Tg = 373K
2-Ethylhexylacrylate: Tg = 223K
As for alkali-soluble resins exhibiting the above-mentioned glass transition temperature (Tg _total ), it is preferable that they are copolymers of an acid monomer and other monomers.

There are no particular limitations on the lower limit of the glass transition temperature (Tg _total ) of the alkali-soluble resin (A) obtained by the above formula (I). The glass transition temperature (Tg _total ) may be 10°C or higher, 30°C or higher, 50°C or higher, or 70°C or higher.

The alkali-soluble resin (A) described above is preferably measured by gel permeation chromatography (GPC), and its weight-average molecular weight (Mw), calculated using a polystyrene calibration curve, is less than 55,000. Here, in the case of a blend of multiple types of alkali-soluble resins (A), this means that the average Mw of those resins is less than the above value (55,000). From the viewpoint of achieving both low tack and high resolution, or solubility in the developer, the Mw of the alkali-soluble resin (A) is preferably less than 55,000, more preferably less than 40,000. On the other hand, from the viewpoint of maintaining a uniform thickness of photosensitive resin laminates such as dry film resists, and from the viewpoints of tack, edge fusing, and cut-tip properties, it is preferable that the Mw be 5,000 or more.

Furthermore, it is preferable that the weight-average molecular weight (Mw) of at least one of the (A) components of the alkali-soluble resin described above is less than 20,000, calculated using a polystyrene calibration curve by measuring the molecular weight of at least one (A) component by gel permeation chromatography (GPC). Here, in the case of a single (A) alkali-soluble resin, this means that the Mw of the single (A) alkali-soluble resin is less than the above value (20,000), and in the case of a blend of multiple (A) alkali-soluble resins, this means that the Mw of any one of the (A) alkali-soluble resins is less than the above value (20,000). The Mw of at least one (A) alkali-soluble resin is preferably less than 20,000 from the viewpoint of achieving both low tack and high resolution, or from the viewpoint of solubility in the developer, while on the other hand, it is preferably 5,000 or more from the viewpoint of maintaining a uniform thickness of the photosensitive resin laminate such as a dry film resist, tack, edge fusing, cut-tip properties, etc.

(A) The alkali-soluble resin preferably contains structural units derived from either acrylic acid or methacrylic acid, or both, and/or structural units derived from aromatic monomer components, from the viewpoint of achieving both low tack and high resolution. Component (A) containing structural units derived from either acrylic acid or methacrylic acid, or both, may be, for example, a (meth)acrylic resin. Component (A) containing structural units derived from aromatic monomer components may be, for example, derivatives of styrene resins, benzyl (meth)acrylic resins, etc.

(A) The alkali-soluble resin is preferably obtained by polymerizing at least one of the first monomers described later. Furthermore, (A) the alkali-soluble resin is more preferably obtained by copolymerizing at least one of the first monomers with at least one of the second monomers described later.

The first monomer is a monomer containing a carboxyl group in its molecule. Examples of the first monomer include (meth)acrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, maleic anhydride, and maleic acid semi-ester. Among these, (meth)acrylic acid is particularly preferred.

The second monomer is a non-acidic monomer having at least one polymerizable unsaturated group in its molecule. Examples of the second monomer include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and benzyl (meth)acrylate; esters of vinyl alcohols such as vinyl acetate; and (meth)acrylonitrile, styrene, and polymerizable styrene derivatives (e.g., methylstyrene, vinyltoluene, tert-butoxystyrene, acetoxystyrene, 4-vinylbenzoic acid, styrene dimer, styrene trimer, etc.). Among these, methyl (meth)acrylate, n-butyl (meth)acrylate, styrene, and benzyl (meth)acrylate are preferred.

Furthermore, (A) the alkali-soluble resin is preferably provided with aromatic groups or alicyclic hydrocarbons in the side chains of its structure, from the viewpoint of improving the resolution of the resist pattern.

Alkali-soluble resins (A) having aromatic groups or alicyclic hydrocarbons in their side chains can be prepared by using compounds having aromatic groups or alicyclic hydrocarbons as the first monomer and/or second monomer. Examples of monomers having aromatic groups include benzyl (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, styrene, cinnamic acid, and polymerizable styrene derivatives (e.g., methylstyrene, vinyltoluene, tert-butoxystyrene, acetoxystyrene, 4-vinylbenzoic acid, styrene dimer, styrene trimer, etc.). Examples of monomers having alicyclic hydrocarbons include isovonyl (meth)acrylate, cyclohexyl (meth)acrylate, and dicyclopentanyl (meth)acrylate. Among these, benzyl (meth)acrylate and styrene are preferred, with benzyl (meth)acrylate being more preferred.

(A) The alkali-soluble resin can be prepared by known polymerization methods, preferably addition polymerization, and more preferably radical polymerization, using the first monomer and/or the second monomer described above.

The content of (A) alkali-soluble resin in the photosensitive resin layer (based on the total solid content of the photosensitive resin layer; the same applies to each component unless otherwise specified) is preferably in the range of 10% to 90% by mass, more preferably in the range of 20% to 80% by mass, and even more preferably in the range of 30% to 60% by mass. From the viewpoint of maintaining the alkali-developability of the photosensitive resin layer, the content of (A) alkali-soluble resin is preferably 10% by mass or more, while from the viewpoint of ensuring that the resist pattern formed by exposure fully exhibits its performance as a resist material, it is preferably 90% by mass or less.

(B) Photopolymerizable compounds having ethylenically unsaturated bonds (B) Photopolymerizable compounds having ethylenically unsaturated bonds are compounds that are polymerizable due to having ethylenically unsaturated bonds, specifically ethylenically unsaturated groups, in their structure.

The photosensitive resin layer may contain one or more ethylenically active double bonds as component (B). It is preferable to use a compound containing two or more ethylenically active double bonds.

Furthermore, the photosensitive resin layer preferably contains, as component (B), a difunctional monomer and a trifunctional or higher polyfunctional monomer, from the viewpoint of achieving both low tack and high resolution.

Specific examples of difunctional monomers include compounds obtained by modifying bisphenol A with alkylene oxide and introducing (meth)acryloyl groups at both ends, and compounds having (meth)acryloyl groups at both ends of bisphenol A. Alkylene oxide modification methods include ethylene oxide modification, propylene oxide modification, butylene oxide modification, pentylene oxide modification, and hexylene oxide modification.

Specific examples of ethylene oxide-modified bisphenol A having (meth)acryloyl groups at both ends include:
- A polyethylene glycol di(meth)acrylate obtained by adding an average of 1 mole of ethylene oxide to each end of bisphenol A.
- A polyethylene glycol di(meth)acrylate obtained by adding an average of 2 moles of ethylene oxide to each end of bisphenol A.
- A polyethylene glycol di(meth)acrylate obtained by adding an average of 3 moles of ethylene oxide to each end of bisphenol A.
- A polyethylene glycol di(meth)acrylate obtained by adding an average of 5 moles of ethylene oxide to each end of bisphenol A.
These are some examples. These may be used individually or in combination of two or more. Among the difunctional monomers described above, from the viewpoint of resolution, side etch amount, and puncture strength, polyethylene glycol dimethacrylate in which an average of 5 moles of ethylene oxide are added to each end of bisphenol A (for example, trade name "MPEM-10"), polyethylene glycol dimethacrylate in which an average of 1 mol of ethylene oxide is added to each end of bisphenol A (for example, trade name "MSR-348"), and bisphenol A dimethacrylate are preferred.

Examples of polyfunctional monomers with three or more functions include (meth)acrylate compounds with three or more functions having a skeleton derived from dipentaerythritol, and optionally, the (meth)acrylate compounds with three or more functions may contain alkylene oxide groups. More specifically, see formula (II) below:
{In the formula, R ₁₀ represents a hydrogen atom, a (meth)acryloyl group, or an alkylene oxide-modified (meth)acryloyl group, and each molecule contains at least three (meth)acryloyl groups.}
Examples include polyfunctional (meth)acrylate compounds having a dipentaerythritol-derived skeleton represented by [formula], tri or tetra(meth)acrylates of pentaerythritol, and tri or tetra(meth)acrylates of polyols obtained by adding an average of 4 to 35 moles of alkylene oxide to pentaerythritol.

In general formula (II), the number of (meth)acryloyl groups in one molecule is three or more, preferably four, five, or six, from the viewpoint of obtaining sufficient cured film strength, resist shape, and resolution. The alkylene oxide-modified (meth)acryloyl group as group R ₁₀ is modified by at least one selected from the group consisting of ethylene oxide, propylene oxide, and butylene oxide, and is preferably ethylene oxide-modified and/or _{propylene oxide-modified. Specifically, -(C2H4O ) m} -CO-CR= _CH2 {wherein R represents a hydrogen atom or a methyl group, and m is an integer from 1 to 30}, -( _C3H6O ) _n -CO-CR= _CH2 {wherein R represents a hydrogen atom or a methyl group, _and n is an integer from 1 to 30}. }, -( _C2H4O ) _m -( _C3H6O ) _{n -CO} -CR= _CH2 {wherein R represents a hydrogen atom or _a methyl group, m is an integer from 1 to 30, n is an integer from 1 to 30, and the arrangement of ( _C2H4O ) _m and ( _C3H6O ) _n may be alternating, random _, or block.} and _so on.

Examples of trifunctional or more (meth)acrylate compounds include:
- Dipentaerythritol tetra(meth)acrylate of polyethylene glycol to which an average of 3 to 27 moles of ethylene oxide have been added.
- Polyethylene glycol with an average of 3 to 27 moles of ethylene oxide added, dipentaerythritol penta(meth)acrylate
- Dipentaerythritol hexa(meth)acrylate of polyethylene glycol with an average of 3 to 27 moles of ethylene oxide added,
- Polyethylene glycol with an average of 3 to 27 moles of propylene oxide added, dipentaerythritol tetra(meth)acrylate
- Polyethylene glycol with an average of 3 to 27 moles of propylene oxide added, dipentaerythritol penta(meth)acrylate
- Polyethylene glycol with an average of 3 to 27 moles of propylene oxide added, dipentaerythritol hexa(meth)acrylate
- Dipentaerythritol tetra, penta, or hexa(meth)acrylate of polyethylene glycol to which an average of 3 to 27 moles of ethylene oxide and an average of 3 to 27 moles of propylene oxide are alternately, randomly, or in blocks.
• Dipentaerythritol tri(meth)acrylate,
• Dipentaerythritol tetra(meth)acrylate,
• Dipentaerythritol penta(meth)acrylate,
• Dipentaerythritol hexa(meth)acrylate,
- Tri(meth)acrylate of polyalkylentriol obtained by adding an average of 3 to 25 moles of alkylene oxide to trimethylolpropane.
- Tetra(meth)acrylate of polyols obtained by adding an average of 4 to 35 moles of alkylene oxide to pentaerythritol.
- Triacrylate obtained by adding an average of 3 moles of ethylene oxide to trimethylolpropane.
- Trimethacrylate obtained by adding an average of 3 moles of ethylene oxide to trimethylolpropane - ε-caprolactone-modified tris(acryloxyethyl) isocyanurate - Combinations of the compounds listed above
These are some examples.

In particular, when using a mixture of hexa(meth)acrylate and penta(meth)acrylate, the proportion of penta(meth)acrylate is preferably less than the proportion of hexa(meth)acrylate, and more preferably about 10% by mass.

Component (B) may include other photopolymerizable compounds in addition to the compounds shown above. Examples of other photopolymerizable compounds include compounds obtained by converting alcohols obtained by adding polyalkylene oxide groups to glycerin, trimethylolpropane, pentaerythritol, diglycerin, ditrimethylolpropane, isocyanurate rings, etc., or by modifying them with ε-caprolactone, into (meth)acrylates; compounds obtained by directly reacting these with (meth)acrylic acid without modifying them with alkylene oxide groups or ε-caprolactone; and dipentaerythritol mono(meth)acrylate. These can be used individually or in combination of two or more.

In the photosensitive resin layer according to this embodiment, the mass ratio (A)/(B) of (A) alkali-soluble resin to (B) photopolymerizable compound having ethylenically unsaturated bonds is preferably less than 1.0, and preferably 0.70 or higher, from the viewpoint of low tack, high resolution, and high adhesion. This mass ratio (A)/(B) is also called the mass ratio B/M of binder resin (B) to monomer (M), and from the same viewpoint, it is more preferably 0.95 or lower.

The content of the photopolymerizable compound having an ethylenically unsaturated bond (B) in the photosensitive resin layer is preferably within the range of 5% to 70% by mass, more preferably 10% to 60% by mass, and even more preferably 20% to 50% by mass. The content of component (B) is preferably 5% by mass or more from the viewpoint of suppressing curing defects and delays in development time of the photosensitive resin layer, while on the other hand, it is preferably 70% by mass or less from the viewpoint of suppressing delays in peeling of the cured resist.

(C) Photopolymerization initiator (C) A photopolymerization initiator is a compound that generates radicals upon exposure to active light and can polymerize (B) photopolymerizable compounds having ethylenically unsaturated bonds. The photosensitive resin layer may contain (C) photopolymerization initiators that are generally known in the art.

(C) Examples of photopolymerization initiators include hexaarylbiimidazole compounds, N-aryl-α-amino acid compounds, quinone compounds, aromatic ketone compounds, acetophenone compounds, acylphosphine oxide compounds, benzoin compounds, benzoin ether compounds, dialkylketal compounds, thioxanthone compounds, dialkylaminobenzoic acid ester compounds, oxime ester compounds, acridine compounds, pyrazoline derivatives, N-aryl amino acid ester compounds, halogen compounds, and the like.

Examples of hexaarylbiimidazole compounds include 2-(o-chlorophenyl)-4,5-diphenylbiimidazole (also known as 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole), 2,2',5-tris-(o-chlorophenyl)-4-(3,4-dimethoxyphenyl)-4',5'-diphenylbiimidazole, 2,4-bis-(o-chlorophenyl)-5-(3,4-dimethoxyphenyl)-diphenylbiimidazole, 2,4,5-tris-(o-chlorophenyl)-diphenylbiimidazole, and 2-(o-chlorophenyl)-bis-4,5-(3,4-dimethoxyphenyl). Toxyphenyl)-biimidazole, 2,2'-bis-(2-fluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3-difluoromethylphenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,4-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,5-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,6-difluorophenyl)- 4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3,4-trifluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3,5-trifluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3,6-trifluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,4,5-trifluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl) Examples include biimidazole, 2,2'-bis-(2,4,6-trifluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3,4,5-tetrafluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, 2,2'-bis-(2,3,4,6-tetrafluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole, and 2,2'-bis-(2,3,4,5,6-pentafluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-biimidazole. Among these, 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer is preferred from the viewpoint of high sensitivity, resolution, and adhesion.

Examples of N-aryl-α-amino acid compounds include N-phenylglycine, N-methyl-N-phenylglycine, and N-ethyl-N-phenylglycine. N-phenylglycine is particularly preferred due to its high sensitizing effect.

Examples of quinone compounds include 2-ethylanthraquinone, octaethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthaquinone, 2-methyl-1,4-naphthoquinone, 9,10-phenanthaquinone, 2-methyl-1,4-naphthoquinone, 2,3-dimethylanthraquinone, and 3-chloro-2-methylanthraquinone.

Examples of aromatic ketone compounds include benzophenone, Michlaz ketone [4,4'-bis(dimethylamino)benzophenone], 4,4'-bis(diethylamino)benzophenone, and 4-methoxy-4'-dimethylaminobenzophenone.
Examples of acetophenone compounds include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1. Examples of commercially available acetophenone compounds include Irgacure-907, Irgacure-369, and Irgacure-379 manufactured by Ciba Specialty Chemicals. From the viewpoint of use as a sensitizer and adhesion, 4,4'-bis(diethylamino)benzophenone is preferred.

Examples of acylphosphine oxide compounds include 2,4,6-trimethylbenzyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. Examples of commercially available acylphosphine oxide compounds include Lucilin TPO from BASF and Irgacure-819 from Ciba Specialty Chemicals.

Examples of benzoin compounds and benzoin ether compounds include benzoin, benzoin ethyl ether, benzoin phenyl ether, methyl benzoin, and ethyl benzoin.
Examples of dialkylketal compounds include benzyldimethyl ketal and benzyldiethyl ketal.
Examples of thioxanthone compounds include 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and 2-chlorthioxanthone.
Examples of dialkylaminobenzoic acid ester compounds include ethyl dimethylaminobenzoate, ethyl diethylaminobenzoate, ethyl-p-dimethylaminobenzoate, and 2-ethylhexyl-4-(dimethylamino)benzoate.

Examples of oxime ester compounds include 1-phenyl-1,2-propanedione-2-O-benzoyl oxime and 1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl) oxime. Examples of commercially available oxime ester compounds include CGI-325, Irgacure-OXE01, and Irgacure-OXE02, manufactured by Ciba Specialty Chemicals.

As for the acridine compound, 1,7-bis(9,9'-acridinyl)heptane or 9-phenylacridine are preferred in terms of sensitivity, resolution, and availability.

As pyrazoline derivatives, 1-phenyl-3-(4-tert-butyl-styryl)-5-(4-tert-butyl-phenyl)-pyrazoline, 1-phenyl-3-(4-biphenyl)-5-(4-tert-butyl-phenyl)-pyrazoline, and 1-phenyl-3-(4-biphenyl)-5-(4-tert-octyl-phenyl)-pyrazoline are preferred from the viewpoint of adhesion and the rectangularity of the resist pattern.

Examples of ester compounds of N-aryl amino acids include methyl ester of N-phenylglycine, ethyl ester of N-phenylglycine, n-propyl ester of N-phenylglycine, isopropyl ester of N-phenylglycine, 1-butyl ester of N-phenylglycine, 2-butyl ester of N-phenylglycine, tert-butyl ester of N-phenylglycine, pentyl ester of N-phenylglycine, hexyl ester of N-phenylglycine, pentyl ester of N-phenylglycine, and octyl ester of N-phenylglycine.

Examples of halogen compounds include amyl bromide, isoamyl bromide, isobutylene bromide, ethylene bromide, diphenylmethyl bromide, benzyl bromide, methylene bromide, tribromomethylphenylsulfone, carbon tetrabromide, tris(2,3-dibromopropyl)phosphate, trichloroacetamide, amyl iodide, isobutyl iodide, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, chlorinated triazine compounds, diallylodonium compounds, etc., with tribromomethylphenylsulfone being particularly preferred.

The content of (C) photopolymerization initiator in the photosensitive resin layer is preferably 0.01% to 20% by mass, and more preferably 0.5% to 10% by mass. By adjusting the content of (C) photopolymerization initiator within the above range, a photosensitive resin layer and photosensitive resin laminate can be obtained that have sufficient sensitivity, allow sufficient light transmission to the bottom of the resist, achieve high resolution, and have an excellent balance with the amount of side etching in the conductor pattern.

(C) It is preferable to use a hexaarylbisimidazole compound as a photopolymerization initiator. In this case, the content of the hexaarylbisimidazole compound in the photosensitive resin layer is preferably 0.1% to 10% by mass, and more preferably 0.5% to 5% by mass.

(C) As a photopolymerization initiator, it is preferable to use an aromatic ketone compound such as 4,4'-bis(diethylamino)benzophenone in combination with a hexaarylbisimidazole compound. In this case, the content of the aromatic ketone compound in the photosensitive resin layer is preferably 0.5% by mass or less, more preferably 0.01% to 0.4% by mass, and the content of the hexaarylbisimidazole compound in the photosensitive resin layer is preferably 0.1% to 10% by mass, more preferably 0.5% to 5% by mass.

(D) End-Modified Silicone Compounds The (D) End-Modified Silicone Compounds of this Disclosure are silicone compounds that have been modified at both ends by carbinol modification, phenol modification, or silanol modification.

Generally, silicone compounds include, for example, condensation-type silicone resins obtained by reacting terminally silanol polydimethylsiloxane with polymethylhydrogensiloxane or polymethylmethoxysiloxane; addition-type silicone resins obtained by reacting dimethylsiloxane-methylvinylsiloxane copolymer or dimethylsiloxane-methylhexenylsiloxane copolymer with polymethylhydrogensiloxane; and UV-curable or electron-beam-curable silicone resins obtained by curing acrylic silicone, epoxy group-containing silicone, etc., with ultraviolet light or electron beams.

(D) The end-modified silicone compound may be a general silicone compound as exemplified above that has been modified at both ends by carbinol modification, phenol modification, or silanol modification, or it may be a silicone resin modified in this manner.

(D) The modification site of the double-ended modified silicone compound may be, for example, both ends of a general silicone compound. In particular, from the viewpoint of achieving both low tack and high resolution, it is preferable that component (D) contains a double-ended modified silicone compound. (D) The double-ended modified silicone compound may contain a carbinol-modified site, a phenol-modified site, or a silanol-modified site within a single molecule, or any combination thereof.

(D) The functional group equivalent of the end-modified silicone compound is preferably 100 to 1500 g/mol, more preferably 300 to 1490 g/mol, and even more preferably 400 to 1480 g/mol, from the viewpoint of achieving both low tack and high resolution.

From the same viewpoint as above, the hydroxyl value of the (D) end-modified silicone compound is preferably in the range of 30 to 130 mg KOH/g.

Examples of carbinol-modified silicone compounds include carbinol-modified silicone resins (e.g., reactive silicone carbinol oil), with single-ended or double-ended carbinol-modified silicone oils being preferred, and double-ended carbinol-modified silicone oils being more preferred.

Examples of phenol-modified silicone compounds include phenol-modified silicone resins (e.g., reactive silicone phenol oil), with single-ended or double-ended silicone phenol oils being preferred, and double-ended silicone phenol oils being more preferred.

Examples of silanol-modified silicone compounds include silanol-modified silicone resins (e.g., reactive silicone silanol oil), with single-ended or double-ended silicone silanol oils being preferred, and double-ended silicone silanol oils being more preferred.

If desired, (D) the end-modified silicone compound may be further modified by carboxyl modification, diol modification, epoxy modification, polyester modification, acrylic modification, alkyd modification, melamine modification, etc., as long as it has been modified by carboxyl modification, phenol modification, or silanol modification.

In this embodiment, it is preferable that the photosensitive resin layer contains a dispersion of the silicone component derived from the (D) end-modified silicone compound described above, from the viewpoint of achieving both low tack and high resolution.

The content of (D) end-modified silicone compound in the photosensitive resin layer is preferably 0.01% to 10% by mass, more preferably 0.05% to 5% by mass, even more preferably 0.10% to 2% by mass, and particularly preferably 0.15% to 1% by mass. Adjusting the content of (D) end-modified silicone compound within the above range tends to reduce unevenness during coating and facilitate achieving both low tack and high resolution.

Other components: The photosensitive resin layer may optionally contain additives such as dyes, plasticizers, antioxidants, and stabilizers.

The photosensitive resin layer preferably contains a dye to impart suitable color development and excellent sensitivity characteristics to the resist-cured film.

Examples of dyes include tris(4-dimethylaminophenyl)methane [leucocrystal violet], bis(4-dimethylaminophenyl)phenylmethane [leucomalachite green], fuchsin, phthalocyanine green, auramine base, paramazienta, crystal violet, methyl orange, Nile blue 2B, Victoria blue, malachite green (manufactured by Hodogaya Chemical Co., Ltd., Eisen®, MALACHITE GREEN), basic blue 20, and diamond green (manufactured by Hodogaya Chemical Co., Ltd., Eisen®, DIAMOND GREEN GH). Among these, leuco dyes such as diamond green and leucocrystal violet are preferred from the viewpoint of improving colorability, hue stability, and exposure contrast. These can be used individually or in combination of two or more.

The dye content in the photosensitive resin layer is preferably in the range of 0.001% to 3% by mass, more preferably in the range of 0.01% to 2% by mass, and even more preferably in the range of 0.04% to 1% by mass. From the viewpoint of obtaining good colorability, the dye content is preferably 0.001% by mass or more, while from the viewpoint of maintaining the sensitivity of the photosensitive resin layer, it is preferably 3% by mass or less. By setting the dye usage ratio within this range, good color development and sensitivity can be achieved.

Examples of plasticizers include glycol esters such as polyethylene glycol, polypropylene glycol, polyoxypropylene polyoxyethylene ether, polyoxyethylene monomethyl ether, polyoxypropylene monomethyl ether, polyoxyethylene polyoxypropylene monomethyl ether, polyoxyethylene monoethyl ether, polyoxyethylene monoethyl ether, polyoxyethylene polyoxypropylene monoethyl ether; sorbitan derivatives such as polyoxyethylene sorbitan laurate and polyoxyethylene sorbitan oleate; phthalate esters such as diethyl phthalate; o-toluenesulfonamide, p-toluenesulfonamide, tributyl citrate, triethyl citrate, triethyl acetyl citrate, tri-n-propyl acetyl citrate, and tri-n-butyl acetyl citrate; propylene glycol obtained by adding propylene oxide to both sides of bisphenol A; ethylene glycol obtained by adding ethylene oxide to both sides of bisphenol A; polyoxyethylene glyceryl ether; and polyoxypropylene glyceryl ether.

In particular, from the viewpoint of suppressing delays in peeling time, p-toluenesulfonamide, polypropylene glycol obtained by adding an average of 3 units of propylene oxide to both ends of bisphenol A, and polyoxypropylene glyceryl ether are preferred. From the viewpoint of resist pattern penetration strength, peeling fragment solubility, or plating resistance, polyoxypropylene glyceryl ether is more preferred, and polyoxypropylene glyceryl ether with a weight-average molecular weight of 3000 is even more preferred.

The plasticizer content in the photosensitive resin layer is preferably in the range of 0.1% to 3% by mass, more preferably 0.15% to 2% by mass. A content of 0.1% by mass or more is preferable from the viewpoint of suppressing delays in development time, imparting flexibility to the cured film, and facilitating adjustment of the maximum point load in the puncture test. On the other hand, a content of 3% by mass or less is preferable from the viewpoint of suppressing insufficient curing and edge fusing.

Examples of antioxidants include triphenyl phosphite (e.g., manufactured by Asahi Denka Kogyo Co., Ltd., trade name: TPP), tris(2,4-di-tert-butylphenyl) phosphite (e.g., manufactured by Asahi Denka Kogyo Co., Ltd., trade name: 2112), tris(mononylphenyl) phosphite (e.g., manufactured by Asahi Denka Kogyo Co., Ltd., trade name: 1178), and bis(mononylphenyl)-dinonylphenyl phosphite (e.g., manufactured by Asahi Denka Kogyo Co., Ltd., trade name: 329K). These can be used individually or in combination of two or more.

The antioxidant content in the photosensitive resin layer is preferably in the range of 0.01% to 0.8% by mass, and more preferably in the range of 0.01% to 0.3% by mass. From the viewpoint of achieving good color stability of the resist pattern and improving the sensitivity of the photosensitive resin layer, the antioxidant content is preferably 0.01% by mass or more. On the other hand, from the viewpoint of achieving good color stability while suppressing the color development of the resist pattern and improving adhesion, it is preferably 0.8% by mass or less.

A stabilizer is preferably used from the viewpoint of improving the thermal stability and/or storage stability of the photosensitive resin layer. Examples of stabilizers include at least one compound selected from the group consisting of radical polymerization inhibitors, benzotriazoles, carboxybenzotriazoles, and alkylene oxide compounds having a glycidyl group. These can be used individually or in combination of two or more.

Examples of radical polymerization inhibitors include p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, tert-butylcatechol, cuprous chloride, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], nitrosophenylhydroxyamine aluminum salts (e.g., aluminum salts with 3 moles of nitrosophenylhydroxylamine added), and diphenylnitrosamines. Among these, triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate] or aluminum salts with 3 moles of nitrosophenylhydroxylamine added are preferred. These can be used individually or in combination of two or more.

Examples of benzotriazoles include 1,2,3-benzotriazole, 1-chloro-1,2,3-benzotriazole, bis(N-2-ethylhexyl)aminomethylene-1,2,3-benzotriazole, bis(N-2-ethylhexyl)aminomethylene-1,2,3-tolyltriazole, bis(N-2-hydroxyethyl)aminomethylene-1,2,3-benzotriazole, and a 1:1 mixture of 1-(2-di-n-butylaminomethyl)-5-carboxylbenzotriazole and 1-(2-di-n-butylaminomethyl)-6-carboxylbenzotriazole. Among these, the 1:1 mixture of 1-(2-di-n-butylaminomethyl)-5-carboxylbenzotriazole and 1-(2-di-n-butylaminomethyl)-6-carboxylbenzotriazole is preferred. These can be used individually or in combination of two or more.

Examples of carboxybenzotriazoles include 4-carboxy-1,2,3-benzotriazole, 5-carboxy-1,2,3-benzotriazole, N-(N,N-di-2-ethylhexyl)aminomethylenecarboxybenzotriazole, N-(N,N-di-2-hydroxyethyl)aminomethylenecarboxybenzotriazole, and N-(N,N-di-2-ethylhexyl)aminoethylenecarboxybenzotriazole. These can be used individually or in combination of two or more.

Examples of alkylene oxide compounds containing a glycidyl group include neopentyl glycol diglycidyl ether (e.g., Epolite 1500NP, manufactured by Kyoeisha Chemical Co., Ltd.), nonaethylene glycol diglycidyl ether (e.g., Epolite 400E, manufactured by Kyoeisha Chemical Co., Ltd.), bisphenol A-propylene oxide 2-mol adduct diglycidyl ether (e.g., Epolite 3002, manufactured by Kyoeisha Chemical Co., Ltd.), and 1,6-hexanediol diglycidyl ether (e.g., Epolite 1600, manufactured by Kyoeisha Chemical Co., Ltd.). These can be used individually or in combination of two or more.

The total content of radical polymerization inhibitors, benzotriazoles, carboxybenzotriazoles, and alkylene oxide compounds having a glycidyl group in the photosensitive resin layer is preferably in the range of 0.001% to 3% by mass, and more preferably in the range of 0.05% to 1% by mass. This total content is preferably 0.001% by mass or more from the viewpoint of imparting good storage stability to the photosensitive resin layer, while it is preferably 3% by mass or less from the viewpoint of maintaining the sensitivity of the photosensitive resin layer.

[Formation of photosensitive resin layer]
The photosensitive resin layer of this disclosure can be formed using a photosensitive resin composition containing the above-mentioned components, or a photosensitive resin composition preparation solution.

A photosensitive resin composition solution can be formed by adding a solvent to a photosensitive resin composition containing the above-mentioned components. Suitable solvents include, for example, ketones such as acetone and methyl ethyl ketone (MEK), and alcohols such as methanol, ethanol, and isopropyl alcohol. It is preferable to add the solvent to the photosensitive resin composition solution so that its viscosity is 500 mPa·sec to 4000 mPa·sec at 25°C.

If desired, a photosensitive resin composition or a photosensitive resin composition solution may be applied to a support and dried as necessary to form a photosensitive resin layer.

[Support]
The support of this disclosure may be, for example, a support film, but is not limited to this.

The support film should preferably be transparent and transmit light emitted from the exposure light source. Examples of such support films include polyethylene terephthalate film, polyvinyl alcohol film, polyvinyl chloride film, vinyl chloride copolymer film, polyvinylidene chloride film, vinylidene chloride copolymer film, polymethyl methacrylate copolymer film, polystyrene film, polyacrylonitrile film, styrene copolymer film, polyamide film, and cellulose derivative film. These films can also be used in stretched form as needed.

The haze of the support film is preferably 5 or less. While a thinner support film is advantageous in terms of image formation and cost-effectiveness, considering the function of maintaining strength, a thickness of 10 μm to 30 μm is preferable.

[Cover film]
The cover film of this disclosure is in contact with the photosensitive resin layer in a photosensitive resin laminate, and more specifically, is in direct contact with the photosensitive resin layer.

The cover film of this disclosure is made of low-density polyethylene (LDPE), more specifically formed from LDPE, and preferably contains or consists of LDPE. Because the cover film contains LDPE, the adhesion force of the cover film to the photosensitive resin layer is sufficiently smaller than the adhesion force of the support to the photosensitive resin layer, and the cover film tends to peel easily from the photosensitive resin laminate.

In a photosensitive resin laminate, the surface roughness Rz of the photosensitive resin layer side of the cover film has the following relationship from the viewpoint of achieving both low tack and high resolution:
200<Rz<800
It is preferable that the following conditions be met.

The thickness of the cover film is not limited to, for example, 1 μm to 100 μm, 10 μm to 50 μm, 15 μm to 45 μm, or 18 μm to 40 μm.

<Method for fabricating photosensitive resin laminates>
A photosensitive resin laminate can be manufactured by sequentially laminating a photosensitive resin layer and a cover film on a support. Known methods can be used for this process. For example, a photosensitive resin composition to be used for the photosensitive resin layer is mixed with a solvent to dissolve it, forming a uniform solution of the photosensitive resin composition (coating liquid). Next, the coating liquid is applied to the support using a bar coater or roll coater, and then dried to laminate the photosensitive resin layer onto the support. Furthermore, a cover film can be placed on the photosensitive resin layer so that the two are in contact, such as by lamination, to produce a photosensitive resin laminate.

<Roll>
In one aspect of the present invention, a roll is provided which is formed by winding the photosensitive resin laminate described above. According to the present invention, even if the photosensitive resin layer and the cover film are pressed together by internal stress due to the rolling process, low tack can be achieved, and consequently, both low tack and high resolution can be achieved.

<Structure>
In another aspect of the present invention:
The photosensitive resin layer in the state after the cover film has been peeled off from the photosensitive resin laminate described above,
A substrate laminated from the side from which the cover film of the photosensitive resin layer has been peeled off,
A structure containing this is provided.

The above structure is obtained from a photosensitive resin laminate that achieves both low tack and high resolution, thus enabling high productivity and high resolution. This structure is sometimes referred to as a photosensitive element in fields such as photolithography.

<Method for forming a resist pattern>
Yet another aspect of the present invention involves the following steps:
A step of peeling a cover film from the photosensitive resin laminate of the present disclosure;
A lamination process in which the surface from which the cover film of the photosensitive resin layer has been peeled off is laminated onto a substrate to form a photosensitive element in a photosensitive resin laminate;
An exposure step for exposing the photosensitive resin layer of a photosensitive element; and a developing step for developing and removing the unexposed portion of the photosensitive resin layer;
The present invention provides a method for forming a resist pattern, including [a specific component].

Furthermore, a wiring pattern formation method can also be provided that includes a step of etching or plating the substrate on which the resist pattern has been formed by the resist pattern formation method described above.

The following describes an example of a method for forming resists and wiring patterns using a photosensitive resin laminate and substrate.

(Process of peeling the cover film from the photosensitive resin laminate)
As described above, the photosensitive resin laminate of this disclosure has low tackiness, so even if a cover film is peeled off the photosensitive resin laminate under any conditions, the phenomenon of the photosensitive resin layer following the cover film (i.e., the photosensitive resin layer separating from the support) is unlikely to occur, or does not occur at all.

(Lamination process)
The lamination process can be carried out, for example, by using a laminator to heat-press the surface from which the cover film of the photosensitive resin layer has been peeled off onto the substrate surface, thereby laminating it.

Examples of materials used for the substrate include copper (Cu), stainless steel (SUS), glass, indium tin oxide (ITO), and flexible substrates with laminated conductive thin films. Examples of conductive thin films include ITO, copper, copper-nickel alloys, and silver. Examples of materials constituting the flexible substrate include polyethylene terephthalate (PET).

The substrate used can be a copper-clad laminate with copper wiring formed on it, a substrate made solely of glass, or a transparent resin substrate with transparent electrodes (e.g., ITO, Ag nanowire substrate, etc.) or metal electrodes (e.g., Cu, Al, Ag, Ni, Mo, and at least two of these alloys, etc.) formed on it. Furthermore, the substrate can have through-holes to accommodate multilayer substrates.

From the viewpoint of significantly demonstrating the effects of the present invention, the substrate used is preferably a copper-clad laminated substrate, and more preferably a copper-clad laminated substrate having a thickness of 1.6 mm, with copper foil layers of 35 μm thickness, and through holes with a diameter of 6 mm.

The photosensitive resin layer may be laminated to only one side of the substrate surface, or, if necessary, to both sides of the substrate. The heating temperature during lamination is preferably 40°C to 160°C, and more preferably 80°C to 120°C. The adhesion of the resulting resist pattern to the substrate can be improved by performing heat bonding two or more times. When performing bonding two or more times, a two-stage laminator equipped with two rolls may be used, or the laminate of the substrate and photosensitive resin layer may be repeatedly passed through the rolls and bonded.

(Exposure process)
In the exposure process, the photosensitive resin layer is exposed using an exposure machine. From the viewpoint of the penetration strength of the resulting resist film, it is preferable to perform this exposure after peeling the support from the photosensitive resin laminate. By performing this exposure in a pattern, a resist film (resist pattern) having the desired pattern can be obtained after going through the development process described later. Pattern exposure may be performed by either exposure via a photomask or maskless exposure.

When exposure is performed via a photomask, the exposure amount is determined by the illuminance of the light source and the exposure time. The exposure amount may also be measured using a light meter. In maskless exposure, a photomask is not used; exposure is performed directly onto the substrate using a drawing device. As the light source, semiconductor lasers with wavelengths of 350 nm to 410 nm, ultra-high pressure mercury lamps, etc., are used. In maskless exposure, the drawing pattern is controlled by a computer, and the exposure amount can be determined by the illuminance of the exposure light source and the moving speed of the substrate.

From the viewpoint of improving the resolution of the resist pattern, reducing the amount of side etching, and improving the yield of the resist or wiring pattern, exposure is preferably performed via a photomask.

(Developing process)
In the developing process, unexposed areas (e.g., non-pattern areas) of the photosensitive resin layer are removed with a developer. In the developing process, a developer consisting of an alkaline aqueous solution is used to dissolve and remove the unexposed areas when a negative-type photosensitive resin composition is used, and to dissolve and remove the exposed areas when a positive-type photosensitive resin composition is used, thereby obtaining a resist pattern.

As the alkaline aqueous solution, it is preferable to use an aqueous solution of, for example, _{Na₂CO₃ or K₂CO₃} . The alkaline aqueous solution is selected according to the characteristics of _the photosensitive resin composition layer, but it is preferable to use an aqueous solution of _Na₂CO₃ with a concentration of 0.2% to ₂ % by mass. A surfactant, an antifoaming agent, and a small amount of organic solvent to promote development may be mixed into the alkaline aqueous solution. It is preferable to maintain the temperature of the developer solution in the development process at a constant temperature in the range of 18°C to 40°C.

If desired, a heating step may be performed after the development process, in which the obtained resist pattern is heated to 100°C to 300°C. This heating step may improve the chemical resistance of the resist pattern. A suitable heating furnace can be used for heating, such as one using hot air, infrared radiation, or far-infrared radiation.

(Etching or plating process)
After forming a resist pattern using the resist pattern formation method described above, a wiring pattern can be formed on the substrate by etching or plating the substrate on which the resist pattern has been formed.

The etching process can be carried out according to known etching methods, for example, by spraying an etching solution onto the resist pattern to etch the substrate surface not covered by the resist pattern. Etching methods include acid etching and alkaline etching, and the method should be suitable for the photosensitive resin laminate being used. The etching solution can be, for example, an aqueous solution of hydrochloric acid, an aqueous solution of ferric chloride, or a mixture thereof. The etching solution can also be sprayed.

The plating process can be carried out by applying metallic plating (e.g., using a copper sulfate plating solution) or solder plating to the substrate surface exposed by development, according to known plating methods.

After the etching and/or plating process, the photosensitive resin laminate may be treated with an aqueous solution having a stronger alkalinity than the developer to remove the resist pattern from the substrate. The stripping solution can be, for example, an aqueous solution of NaOH or KOH with a concentration of approximately 2% to 5% by mass and a temperature of approximately 40°C to 70°C.

Unless otherwise specified, the evaluation values of the various parameters mentioned above are measured values obtained according to the measurement methods described in the examples below.

While embodiments of the present invention have been described above, the present invention is not limited thereto and can be modified as appropriate without departing from the spirit of the invention.

The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

<1. Preparation of Photosensitive Resin Composition>
A photosensitive resin composition was prepared by mixing the components shown in Tables 1 and 2. The values in Tables 1 and 2 represent the solid content.

<2. Manufacturing of Photosensitive Resin Laminates>
A solvent, acetone, was added to the photosensitive resin composition until the solid content reached 58% by mass. The mixture was thoroughly stirred and mixed. The solution of the photosensitive resin composition was uniformly applied to a polyethylene terephthalate film using a bar coater and dried in a 95°C dryer for 5 minutes to form a 5 μm thick photosensitive resin layer (dry film). Next, a cover film (for example, LDPE, OPP, or an easily peelable PET film, indicated as H-1 in Tables 1 and 2) was laminated onto the surface of the photosensitive resin layer to obtain a photosensitive resin laminate.

<3. Fabrication of the Evaluation Board>

laminate:
The photosensitive resin laminate was laminated onto a copper-layered PET substrate using a hot roll laminator (Asahi Kasei Electronics Corporation, AL-700) at a roll temperature of 105°C while peeling off the cover film. The air pressure was set to 0.35 MPa and the lamination speed to 1.5 m/min.

exposure:
A polyethylene terephthalate film, used as a support, was peeled from the photosensitive resin laminate, and the evaluation substrate was exposed using a chromium glass photomask and an exposure machine equipped with an ultra-high pressure mercury lamp (parallel light exposure machine (HMW-801, manufactured by Oak Manufacturing Co., Ltd.)).

developing:
Using a developing system manufactured by Fuji Kiko Co., Ltd., the film was developed by spraying it with a 1% by mass _{Na₂CO₃ aqueous} solution at 23°C for 30 seconds using a full-cone type nozzle at a spray pressure of 0.15 MPa, dissolving and removing the unexposed portions of the photosensitive resin layer. The rinsing process was performed using a flat-type nozzle at a rinsing spray pressure of 0.15 MPa for the same duration as the developing process.

etching:
Using an etching apparatus manufactured by Fuji Kiko Co., Ltd., etching was performed for 60 seconds (s) with a full-cone type nozzle, at a spray pressure of 0.15 MPa and a temperature of 30°C, using hydrochloric acid concentration of 2% by mass and ferric chloride concentration of 2% by mass.

Peeling:
Using a stripping device manufactured by Fuji Kiko Co., Ltd., the resist was stripped and removed from the substrate by spraying a 3% by mass NaOH aqueous solution at a spray pressure of 0.15 MPa and a temperature of 50°C using a full-cone type nozzle for 30 seconds (s).

<4. Evaluation Method>

Image quality evaluation:
A photosensitive resin laminate with a photosensitive resin layer thickness of 5 μm was laminated using the method described in <Lamination> above. After 15 minutes, the evaluation substrate was exposed through a chromium glass mask having a line pattern with a 1:1 ratio of exposed to unexposed areas. Subsequently, it was developed using the method described in <Development> above to produce a resist pattern.
The minimum mask width in which the fabricated cured resist lines were formed normally was defined as the resolution value, and the resolution was ranked as follows. The evaluation considered the minimum mask width in which the cured resist patterns were not tilted or adhered to each other, and where the cured resists were formed normally.
◎: Resolution value of 2 μm or less;
○: Resolution value greater than 2 μm and 3 μm or less;
△: Resolution value exceeds 3 μm and is 4 μm or less;
×: The resolution value exceeds 4 μm.

Peel strength of the cover layer (LDPE film):
The photosensitive resin laminate was cut into strips measuring 1 inch x 11 cm and left for 24 hours at 23°C and 50% relative humidity. The cover film (in this example, LDPE, easily peelable PET, or OPP film) was peeled off at 180°, and its strength was measured using a Tensilon RTM-500 (manufactured by Toyo Seiki), and ranked as follows.
◎: Peel strength is greater than 1.5 gf/inch and 2.5 gf/inch or less ○: Peel strength is greater than 2.5 gf/inch and 3 gf/inch or less △: Peel strength is greater than 3 gf/inch and 3.5 gf/inch or less ×: Peel strength is greater than 3.5 gf/inch.

Peel strength (tackiness) of the support layer (PET film):
A substrate was prepared by laminating a photosensitive resin layer of a photosensitive resin laminate to one side using the method described above. After leaving it for 24 hours at 23°C and 50% relative humidity, a 1-inch wide support (PET film in this example) was peeled off at 180°, and its strength was measured using a Tensilon RTM-500 (manufactured by Toyo Seiki), and ranked as follows.
◎: Peel strength is greater than 8 gf/inch and 10 gf/inch or less ○: Peel strength is greater than 10 gf/inch and 12 gf/inch or less △: Peel strength is greater than 12 gf/inch and 14 gf/inch or less ×: Peel strength is greater than 14 gf/inch.

Coating properties evaluation:
A solution of each photosensitive resin composition was uniformly applied to a polyethylene terephthalate film using a bar coater, and dried in a 95°C dryer for 5 minutes to form a 5 μm thick photosensitive resin layer (dry film).
The appearance of the formed films was observed and ranked as follows.
○: No abnormalities in the appearance of the coating film. ×: Defects such as clouding or repelling occurred in the appearance of the coating film.

Side etching (SE) amount:
For evaluating the amount of side etching, an evaluation substrate was used in which a photosensitive resin laminate with a photosensitive resin layer thickness of 5 μm was laminated onto a copper-layered PET substrate using the method described in <Lamination> above, and then left for 15 minutes.
The laminate evaluation substrate was exposed to a pattern with a line/space of 10 μm/10 μm, and then developed using the method described in <Development> above.
The resist top width Wr (μm) of the fabricated pattern was measured using an optical microscope. Next, the substrate having this line/space pattern was etched using the dip method with an aqueous solution containing 2% by mass hydrochloric acid and 2% by mass ferric chloride, at a temperature of 30°C, for a time 1.5 times the minimum etching time. Here, the minimum etching time refers to the minimum time required for the copper foil on the substrate to be completely dissolved and removed under the above conditions.
After etching as described above, a 3% by mass aqueous NaOH solution was used as a stripping solution, and the hardened film on the substrate was removed at a temperature of 50°C. The top width Wc (μm) of the obtained copper line pattern was measured using an optical microscope.
And then, the following formula:
Side etch (μm) = (Wr - Wc) ÷ 2
The amount of side etching was calculated and then ranked as follows.
◎ (Excellent): The amount of side etching is 2.5 μm or less;
○ (Good): The amount of side etching is greater than 2.5 μm and less than or equal to 3.0 μm;
△ (Acceptable): The amount of side etching is greater than 3.0 μm and less than or equal to 3.5 μm;
× (Defective): Side etching amount exceeds 3.5 μm.

Puncture strength evaluation:
For evaluation, a copper-clad laminate substrate with a thickness of 1.6 mm, consisting of 35 μm copper foil layers, was used. This substrate had 1,008 through-holes with a diameter of 6 mm formed on it, and its surface was smoothed using a jet scrub polishing machine.
On a surface-prepared substrate, a photosensitive resin laminate with a photosensitive resin layer thickness of 25 μm was laminated on both sides using a hot roll laminator (Asahi Kasei Corporation, AL-70) under the conditions of a roll temperature of 105°C, an air pressure of 0.35 MPa, and a lamination speed of 1.5 m/min, while peeling off the cover film.
Using a substrate that had been laminated for 15 minutes, the laminated substrate was exposed to light using an exposure machine equipped with an ultra-high pressure mercury lamp (parallel light exposure machine (HMW-801, manufactured by Oak Manufacturing Co., Ltd.)) at an exposure dose of 60 mJ/ ^cm² , and then developed using the method described in <Development> above. The developed substrate was conditioned overnight in a room at a temperature of 25°C and a humidity of 50%.
After standing, the PET film used as a support was peeled off the obtained substrate. A 2.0 mm diameter cylinder was then thrust into the center of a 6 mm diameter opening from the side where the support had been peeled off, at a speed of 100 mm/min. The maximum point load was measured using a Tensilon (RTM-500, manufactured by Orientec Co., Ltd.). The maximum point load was measured at 10 locations, and the average of the top 5 points was used as the maximum point load for the thrust test. The samples were then ranked according to the following criteria.
◎ (Excellent): Puncture strength exceeds 150 gf;
○ (Good): Puncture strength is above 100 gf and below 150 gf;
× (Defective): Puncture strength is 100 gf or less.

Surface free energy evaluation:
The cover film was peeled off from the photosensitive resin laminate, and two films were prepared: one with the surface of the photosensitive resin layer exposed, and another with the surface of the cover film that was in contact with the photosensitive resin layer exposed.
The contact angles of water, diiodomethane, and ethylene glycol were measured for the aforementioned photosensitive resin layer film and cover film, and the surface free energy _γSL (mJ/ ^m² ) of each film was calculated from these contact angles using the following formula.
γ _SL = γ _S + γ _L − (2(γ _S ^d γ _L ^d ) ^1/2 + 2(γ _S ^P γ _L ^P ) ^1/2 + 2(γ _S ^h γ _L ^h ) ^1/2 ))
W _SL = 2 ((γ _S ^d γ _L ^d ) ^1/2 + (γ _S ^P γ _L ^P ) ^1/2 + (γ _S ^h γ _L ^h ) ^1/2 ))
(γ _S ^d γ _L ^d ) ^1/2 + (γ _S ^P γ _L ^P ) ^1/2 + (γ _S ^h γ _L ^h ) ^1/2 = γ _L (1+cosθ)/2
In the table, "Surface Free Energy Difference (mJ/ ^m² )" represents the absolute value of the difference between the surface free energy of the photosensitive resin layer and the surface free energy of the cover film.

The evaluation results for Examples 1-15 and Comparative Examples 1-13 are shown in Table 1, and the details of the components of the photosensitive resin laminate are shown in Table 2.

Claims (14)

A photosensitive laminate comprising a support, a photosensitive resin layer, and a cover film,
The photosensitive resin layer and the cover film are in contact with each other.
The cover film is low-density polyethylene, and the photosensitive resin layer has the following components:
(A) Alkali-soluble resin (B) Photopolymerizable compound having an ethylenically unsaturated bond,
A photosensitive resin laminate characterized by containing (C) a photopolymerization initiator and (D) a double-ended modified silicone compound, wherein the double-ended modified silicone compound is modified by carbinol modification, phenol modification, or silanol modification, and which includes a step of etching or plating a substrate on which a resist pattern has been formed. The photosensitive resin laminate according to claim 1, wherein the alkali-soluble resin (A) contains constituent units derived from either acrylic acid or methacrylic acid, or both. The photosensitive resin laminate according to claim 1 or 2, wherein the (B) photopolymerizable compound having an ethylenically unsaturated bond comprises a difunctional monomer and a trifunctional or polyfunctional monomer. The photosensitive resin laminate according to any one of claims 1 to 3, wherein the functional group equivalent of the (D) end-modified silicone compound is 100 to 1500 g/mol. The photosensitive resin laminate according to any one of claims 1 to 4, wherein the weight-average molecular weight of the alkali-soluble resin (A) is less than 55,000. A photosensitive resin laminate according to any one of claims 1 to 5, wherein the weight-average molecular weight of at least one of the alkali-soluble resins (A) is less than 20,000. The photosensitive resin laminate according to any one of claims 1 to 6, wherein the mass ratio (A)/(B) of the alkali-soluble resin to the photopolymerizable compound having an ethylenically unsaturated bond (B) is less than 1.0. The photosensitive resin laminate according to any one of claims 1 to 7, wherein the silicone component derived from the (D) end-modified silicone compound is dispersed in the photosensitive resin layer. The photosensitive resin laminate according to any one of claims 1 to 8, wherein the (D) double-ended modified silicone compound comprises a double-ended modified silicone compound modified by either double-ended carbinol modification, double-ended phenol modification, or double-ended silanol modification. The photosensitive resin laminate according to any one of claims 1 to 9, wherein the difference between the surface free energy of the cover film surface in contact with the photosensitive resin layer and the surface free energy of the photosensitive resin layer surface in contact with the cover film is 20 mJ/ ^m² or more. The photosensitive resin laminate according to any one of claims 1 to 10, wherein the alkali-soluble resin (A) contains constituent units derived from aromatic monomers or alicyclic monomer components. The photosensitive resin laminate according to any one of claims 1 to 11, wherein the thickness of the photosensitive resin layer is 10 μm or less. A roll formed by winding a photosensitive resin laminate according to any one of claims 1 to 12. The following steps:
A step of peeling the cover film from the photosensitive resin laminate according to any one of claims 1 to 12;
A lamination step in which the surface of the photosensitive resin layer from which the cover film has been peeled off is laminated onto the substrate to form a photosensitive element;
An exposure step of exposing the photosensitive resin layer of the photosensitive element; and a developing step of developing and removing the unexposed portion of the photosensitive resin layer;
By doing so , a resist pattern is formed ,
Furthermore, the process includes etching or plating the substrate on which the resist pattern is formed;
Method for forming wiring patterns.