Photosensitive element, and method for forming resist pattern

Abstract

To provide a photosensitive element.SOLUTION: A photosensitive element has a support film (A) and a photosensitive resin composition layer (B) in this order, where a developed area ratio SdrA2 (%) of the interface of the support film (A) on the side thereof in contact with the photosensitive resin composition layer (B) and a developed area ratio SdrA1 (%) of the interface on the reverse side thereof, defined in accordance with ISO 25178, satisfy formula (1): SdrA1 / SdrA2<0.75 (1).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a photosensitive element and a method for forming a resist pattern. [Background technology]

[0002] In electronic devices such as personal computers and mobile phones, printed wiring boards and the like are used for mounting components, semiconductors, etc. Conventionally, as a resist for producing printed wiring boards and the like, a photosensitive element (photosensitive resin laminate) formed by laminating a photosensitive resin composition layer on a support film and, if necessary, further laminating a protective film on the photosensitive resin composition layer, that is, a so-called dry film resist, has been used.

[0003] In such photosensitive elements, the exposure step for curing the photosensitive layer is performed via a support film, and therefore the characteristics of the support film have a significant effect on the resolution. For this reason, a support film containing a lubricant that blocks the exposing light or a film with little internal foreign matter is preferably used (see, for example, Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4014872 [Patent Document 2] International Publication No. 2018 / 100730 [Patent Document 3] Patent No. 5814667 [Patent Document 4] International Publication No. 2018 / 105620 Summary of the Invention [Problem to be solved by the invention]

[0005] As the resolution of printed circuit board wiring continues to increase, the composition and amount of compounds in photosensitive resin compositions have been explored. In recent years, compositions containing a large amount of styrene as a comonomer component in alkali-soluble polymers forming the photosensitive resin layer have become more popular. Styrenic alkali-soluble polymers are essential for achieving high resolution because they do not swell easily during alkaline development. However, they suffer from low tackiness, which means they have low adhesive strength to the support film and are prone to falling off from the photosensitive resin layer. Low-tack photosensitive elements can cause the support film to peel off when the substrate is lifted by the equipment during transport after lamination, potentially disrupting production. To achieve high tack, a rougher surface roughness on the support film's surface that comes into contact with the photosensitive resin layer is advantageous because it increases the adhesive surface area and enhances the anchoring effect (the photosensitive resin layer penetrates into the fine irregularities of the support film, improving adhesion).

[0006] On the other hand, in recent years, the demand for higher resolution has increased, with the demand for a resist resolution of L / S = 5 / 5 μm or less after development. For fine resist patterns, it is advantageous for high resolution that the side surfaces of the resist pattern are flat and free of unevenness so that adjacent patterns do not come into contact with each other, i.e., the sidewalls have good straightness. In the past, studies have been conducted on the composition and amount of compounds in photosensitive resin compositions to improve the straightness of sidewalls, and while wobble of 1 μm or more has been reduced to some extent, wobble of less than 1 μm has yet to be eliminated.

[0007] Sidewall wobble is caused by various factors, one of which is the influence of the support film. Typically, when exposing a photosensitive element, actinic radiation is irradiated onto the photosensitive resin layer through a support film. Therefore, refraction or scattering of light by the support film can cause wobble in the photosensitive resin layer. To address this issue, a method using an exposure machine with a high numerical aperture lens is known to improve the straightness of the sidewall without relying on improvements to the photosensitive element. Because high-numerical aperture lenses have a shallow depth of field, focusing only on the photosensitive resin layer minimizes the effects of refraction and scattering by the support film. While this method is effective on flat substrates such as wafers and glass substrates, copper-clad laminates, which are commonly used in printed wiring boards, have significant waviness and unevenness due to the organic substrate, making them prone to defocusing across the entire substrate. In areas where defocusing occurs, the resolution and sidewall straightness of the resist pattern deteriorate significantly, making it difficult to apply exposure machines (especially projection exposure machines) that use lenses with high numerical apertures to organic substrates with large undulations.

[0008] Therefore, a solution on the material side is preferable, and in order to achieve the highly advanced resolution demands that have been made in recent years, a photosensitive element is required that does not only have a wobble of 1 μm or more, but also has a sidewall wobble of less than 1 μm.

[0009] The present invention has been proposed in view of the above-described conventional circumstances, and an object of the present invention is to provide a photosensitive element and a method for forming a resist pattern that achieve high tack and high resolution. [Means for solving the problem]

[0010] [1] A photosensitive element having a support film (A) and a photosensitive resin composition layer (B) in this order, The developed area ratio Sdr of the interface of the support film (A) on the side opposite to the side in contact with the photosensitive resin composition layer (B), as defined in ISO 25178A1 (%)but, Sdr A1 <0.005(%) A photosensitive element comprising: [2] A photosensitive element having a support film (A) and a photosensitive resin composition layer (B) in this order, The developed area ratio Sdr of the interface of the support film (A) on the side in contact with the photosensitive resin composition layer (B), as defined in ISO 25178 A2 (%), development area ratio Sdr of the opposite interface A1 (%) is expressed by the following formula (1): Sdr A1 / Sdr A2 <0.75 (1) A photosensitive element characterized by satisfying the above. [3] A photosensitive element having a support film (A) and a photosensitive resin composition layer (B) in this order, The number P of surface particles of 1.0 μm or more contained in an area of ​​258 μm×260 μm on the surface of the support film (A) in contact with the photosensitive resin composition layer (B) A2 (particles), the number of surface particles on the opposite side P A1 (pieces) are expressed by the following formula (2): P A1 / P A2 <0.75 (2) A photosensitive element characterized by satisfying the above. [4] A photosensitive element having a support film (A) and a photosensitive resin composition layer (B) in this order, The maximum surface particle diameter S of the surface of the support film (A) that comes into contact with the photosensitive resin composition layer (B) A2 (μm), maximum surface grain size S on the opposite side A1 (μm) is expressed by the following formula (3): S A1 / S A2 <0.75 (3) A photosensitive element characterized by satisfying the above. [5] The photosensitive element according to any one of [1] to [4], wherein in the photosensitive resin composition layer (B), the ratio of comonomers having an aromatic ring structure in the binder is 50% or more. [6] The photosensitive element according to [5], wherein the structure having an aromatic ring is styrene. [7] The following steps: a lamination step of laminating the photosensitive element according to any one of [1] to [6] on a substrate; 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; The method for forming a resist pattern, wherein the exposure step is carried out by a projection exposure method. [8] The following steps: a lamination step of laminating the photosensitive element according to any one of [1] to [6] on a substrate; 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; The method for forming a resist pattern, wherein the exposure step is carried out with an exposure wavelength of 405 nm or less. [9] The photosensitive element can be laminated to a copper substrate having a copper seed layer with an average thickness of 1 um or less, For the photosensitive element laminated to the copper substrate, (1) Exposure using an exposure mask with a 10 μm pitch between exposed and unexposed areas (2) Formation of lines / spaces in the photosensitive resin layer by development after the exposure. When you do Average space width D W1 and the minimum space width D W2 Toga 1.00 <D W1 / D W2 <1.10 The photosensitive element according to any one of [1] to [6], which satisfies the relationship:

[10] The photosensitive element can be laminated to a copper substrate having a copper seed layer with an average thickness of 1 um or less, (1) Exposure using an exposure mask with a 10 μm pitch between exposed and unexposed areas (2) Formation of lines / spaces in the photosensitive resin layer by development after the exposure. (3) Forming a plating pattern by plating the space. (4) Peeling off the photosensitive resin layer from the substrate When you do Average plating pattern width P W1 and the minimum plating pattern width P W2 Toga 1.00 <P W1 / P W2 <1.10 The photosensitive element according to any one of [1] to [6], which satisfies the relationship:

[11] The photosensitive element can be laminated to a copper substrate having a copper seed layer with an average thickness of 1 um or less, (1) Exposure using an exposure mask with a 10 μm pitch between exposed and unexposed areas (2) Formation of lines / spaces in the photosensitive resin layer by development after the exposure. (3) Forming a plating pattern by plating the space. (4) Peeling off the photosensitive resin layer from the substrate (5) Formation of a post-etching plating pattern remaining after etching the copper seed layer on the substrate after the peeling. When you do Average plating pattern width after etching F W1 and the minimum plating pattern width after etching F W2 Toga 1.00 <F W1 / F W2 <1.10 The photosensitive element according to any one of [1] to [6], which satisfies the relationship:

[12] A method for forming a conductor pattern using the photosensitive element according to any one of [1] to [6], comprising: the photosensitive element can be laminated to a copper substrate having a copper seed layer with a thickness t (um); For the photosensitive element laminated to the copper substrate, (1) Exposure using an exposure mask with an X (μm) pitch between exposed and unexposed areas (2) Formation of lines / spaces in the photosensitive resin layer by development after the exposure. When I did Average space width D W1 is equal to or greater than {((X / 2)±10%)+t}, (3) Forming a plating pattern by plating the space. (4) Peeling off the photosensitive resin layer from the substrate When I did Average plating pattern width P W1 However, the average space width D W1 A method for forming a conductor pattern, wherein the difference is within ±10% of the above.

[13] After the conductive pattern forming method described in

[12] , (5) Formation of a post-etching plating pattern remaining after etching the copper seed layer on the substrate after the peeling. When I did Average plating pattern width after etching F W1 The average plating pattern width P W1 A method for forming a wiring pattern that is smaller than the above. [Effects of the Invention]

[0011] The present invention can provide a photosensitive element and a method for forming a resist pattern that achieve high tack and high resolution. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view schematically illustrating one example of the configuration of a photosensitive element of the present invention. [Figure 2]FIG. 2 is a diagram schematically illustrating how actinic rays incident on a support film during exposure are refracted before reaching a photosensitive resin layer in the photosensitive element shown in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments for carrying out the present invention will be described in detail. In the following description, numerical ranges indicated using "to" include the upper and lower limit values. [Embodiment 1] [Photosensitive element] FIG. 1 is a cross-sectional view schematically illustrating one example of the configuration of the photosensitive element of the present invention. The photosensitive element of the present invention is a photosensitive element having a support film (A), a photosensitive resin composition layer (B), and a protective film (C) in this order, The developed area ratio Sdr of the interface (A1) on the side opposite to the side in contact with the photosensitive resin composition layer (B) of the support film (A) as specified in ISO 25178 A1 (%)but, Sdr A1 <0.005(%) It is characterized in that:

[0014] The photosensitive element of the present invention is a photosensitive element having a support film (A), a photosensitive resin composition layer (B), and a protective film (C) in this order, The developed area ratio Sdr of the interface (A2) of the support film (A) on the side in contact with the photosensitive resin composition layer (B), as specified in ISO 25178 A2 (%), the development area ratio Sdr of the opposite interface (A1) A1 (%) is expressed by the following formula (1): Sdr A1 / Sdr A2 <0.75 (1) The present invention is characterized in that:

[0015] The photosensitive element of the present invention is a photosensitive element having a support film (A), a photosensitive resin composition layer (B), and a protective film (C) in this order, The number P of surface particles of 1.0 μm or more contained in an area of ​​258 μm × 260 μm on the surface (A2) of the support film (A) that contacts the photosensitive resin composition layer (B) A2 (particles), the number of surface particles on the opposite side (A1) P A1 (pieces) are expressed by the following formula (2): P A1 / P A2 <0.75 (2) The present invention is characterized in that:

[0016] In this specification, the number of surface particles P is the number of particles of 1.0 μm or more contained in an area of ​​258 μm×260 μm of the support film (A) as measured using a laser microscope.

[0017] The photosensitive element of the present invention is a photosensitive element having a support film (A), a photosensitive resin composition layer (B), and a protective film (C) in this order, The maximum surface particle diameter S of the surface (A2) of the support film (A) that comes into contact with the photosensitive resin composition layer (B) A2 (μm), maximum surface particle size S on the opposite side (A1) A1 (μm) is expressed by the following formula (3): S A1 / S A2 <0.75 (3) The present invention is characterized in that:

[0018] In this specification, the maximum surface particle diameter S is a value measured using a laser microscope. When a particle is not a perfect sphere, the longest width of the particle is taken as the diameter of the particle.

[0019] The present inventors have investigated the effect of the surface shape of the support film (A) on tackiness and resolution, and have found that in order to improve sidewall wobble, i.e., to increase the straightness of the pattern formed, the surface roughness or number of surface particles on the surface (coated surface) A2 of the support film (A) on which the photosensitive resin composition layer (B) is coated and formed has almost no effect, but the surface roughness or number of surface particles on the opposite surface (uncoated surface) A1 is important.

[0020] This is thought to be because the refractive index of light incident from the support film (A) to the photosensitive resin layer (B) is smaller than that of light incident from the atmosphere onto the support film (A). As shown in Figure 2, the inventors speculate that if the surface roughness of the uncoated surface (A1) of the support film (A) is large, the light incident from the atmosphere onto the support film (A) is largely refracted (arrow on the left), but if the surface roughness of the uncoated surface (A1) is small, the light incident from the atmosphere onto the support film (A) is hardly refracted (arrow on the right), resulting in the formation of a pattern with high mask reproducibility and reduced sidewall wobble.

[0021] By reducing the surface roughness of the uncoated surface A1 of the support film (A), it is possible to reduce sidewall wobble and achieve high resolution, while by increasing the surface roughness of the coated surface A2, the contact area between the support film (A) and the photosensitive resin layer (B) increases, enhancing the anchoring effect and achieving high tackiness.

[0022] That is, in the photosensitive element of the present invention, the developed area ratio Sdr of the support film (A) is A1 )<Coated surface (Sdr A2 ) or the number of surface particles P of the support film (A) is the number of particles on the uncoated surface (P A1 )<Coated surface (P A2 ) or the maximum surface particle size S of the support film (A) is A1 )<Coated surface (S A2 ) can achieve high tack and high resolution.

[0023] If the developed area ratio Sdr, the number of surface particles P, or the maximum surface particle diameter S of the coating surface of the support film (A) is large, the surface irregularities will increase as they are transferred to the photosensitive resin layer (B), but this will not affect the resolution or the straightness of the sidewalls.

[0024] Conventionally, it has been recognized that it is sufficient for the coated surface (one side) to be smooth in order to improve the appearance of the resist shape or to prevent irregularities caused by the surface roughness of the support film (A) from being transferred to the photosensitive resin layer, and in recent years, many support films (A) with only one side smoothed have been used for dry film applications. However, the smooth side is applied to the side that comes into contact with the photosensitive resin layer, and there is no precedent for using the opposite side. That is, in the present invention, by coating on the surface opposite to that of a normal surface, a photosensitive element having high tack and high resolution can be provided.

[0025] <Support film (A)> The support film (A) according to this embodiment is a layer or film for supporting the photosensitive resin composition layer (B), and is preferably a transparent substrate film that transmits actinic rays emitted from an exposure light source.

[0026] Examples of such support films include polyethylene terephthalate films, polyvinyl alcohol films, polyvinyl chloride films, vinyl chloride copolymer films, polyvinylidene chloride films, vinylidene chloride copolymer films, polymethyl methacrylate copolymer films, polystyrene films, polyacrylonitrile films, styrene copolymer films, polyamide films, and cellulose derivative films. These films can also be stretched as needed. Polyethylene terephthalate (PET), which has appropriate flexibility and strength, is usually preferred.

[0027] Among these, it is preferable to use a high-quality film with little internal foreign matter. Specifically, as the high-quality film, it is more preferable to use a PET film synthesized using a Ge-based catalyst, a PET film synthesized using a Ti-based catalyst, a PET film with a small diameter of lubricant and a small content, a PET film containing lubricant on only one side of the film, a thin PET film, a PET film smoothed on at least one side, a PET film roughened on at least one side by plasma treatment, etc. This allows the exposure light to be irradiated onto the photosensitive resin composition layer (B) without being blocked by internal foreign matter, thereby improving the resolution of the photosensitive element.

[0028] The number of particles with a diameter of 2 μm or more and 5 μm or less contained in the support film (A) as internal foreign matter is 30 / 30 mm. 2 Preferably less than 15 pieces / 30 mm 2 It is more preferable that the number of pieces is 10 pieces / 30 mm or less. 2 It is even more preferable that:

[0029] The content of titanium element (Ti) contained in the support film (A) is preferably 1 ppm or more and 20 ppm or less, more preferably 2 ppm or more and 12 ppm or less. If the content of titanium element is 20 ppm or less, the number of internal foreign matters originating from titanium element-containing aggregates can be reduced, and a decrease in resolution can be prevented.

[0030] The thickness of the support film (A) is preferably 5 μm or more and 16 μm or less, and more preferably 6 μm or more and 12 μm or less. The thinner the support film, the fewer the number of internal foreign matter and the more likely it is to prevent a decrease in resolution. However, if the thickness is less than 5 μm, the film may be stretched and deformed in the winding direction due to tension during the coating and winding manufacturing process, or may tear due to minute scratches, or the film may not be strong enough to cause wrinkles during lamination.

[0031] At least one surface of the support film (A) is preferably subjected to a smoothing treatment using a calender, etc. This reduces the surface roughness of one surface of the support film (A), particularly the surface A2 on the side not in contact with the photosensitive resin composition layer (B), thereby enhancing the effects of the present invention.

[0032] The haze of the support film (A) is preferably 0.01% to 1.5%, more preferably 0.01% to 1.0%, and even more preferably 0.01% to 0.5%, from the viewpoint of improving the parallelism of the light beam irradiated onto the photosensitive resin composition layer (B) and obtaining higher resolution after exposure and development of the photosensitive element.

[0033] In the photosensitive element of this embodiment, the developed area ratio Sdr of the surface (A2) of the support film (A) that contacts the photosensitive resin composition layer (B), as specified in ISO 25178, A2 (%), development area ratio Sdr of the opposite surface (A1) A1 (%) satisfies the following formula (1). Sdr A1 / Sdr A2 <0.75 (1)

[0034] The photosensitive element is formed by dividing the developed area ratio Sdr of the support film (A) by the uncoated surface (Sdr A1 )<Coated surface (Sdr A2 ) achieves high tack and high resolution.

[0035] A specific method for measuring the developed area ratio Sdr will be described in the examples below. From the viewpoint of suitably achieving the effects of the present invention, Sdr A1 / Sdr A2 is preferably less than 0.60, more preferably less than 0.55, and even more preferably less than 0.50. A1 / Sdr A2 can be greater than 0.

[0036] Sdr A1 and Sdr A2is not particularly limited as long as it satisfies the above formula (1), but specifically, Sdr A1 Sdr A1 <0.005(%), preferably 0.0005% to 0.004%, more preferably 0.0005% to 0.003%, extremely preferably 0.0005% to 0.002%, and extremely extremely preferably 0.0005% to 0.001%. Sdr A2 is preferably 0.006% to 0.03%, more preferably 0.006% to 0.02%, very preferably 0.006% to 0.01%, and extremely preferably 0.006% to 0.008%.

[0037] Alternatively, the photosensitive element of this embodiment has a surface particle number P of 1.0 μm or more contained in an area of ​​258 μm×260 μm on the surface (A2) of the support film (A) that contacts the photosensitive resin composition layer (B). A2 (particles), the number of surface particles on the opposite side (A1) P A1 (pieces) satisfy the following formula (2). P A1 / P A2 <0.75 (2)

[0038] The photosensitive element has a surface particle number P of the support film (A) and a surface particle number P of the uncoated surface (P A1 )<Coated surface (P A2 ) achieves high tack and high resolution.

[0039] A specific method for measuring the number of surface particles P will be described in the examples below.

[0040] P A1 and P A2 is not particularly limited as long as it satisfies the above formula (1), but specifically, P A1 The number is preferably 1 to 200, more preferably 1 to 150. It is very preferably 1 to 100, and very, very preferably 1 to 50. PA2 is preferably 300 to 1500, more preferably 300 to 1000, very preferably 300 to 800, and very, very preferably 300 to 500. Also, P A2 / P A1 is more preferably 0.001 to 0.5, very preferably 0.001 to 0.4, and very, very preferably 0.001 to 0.3.

[0041] Alternatively, the photosensitive element of this embodiment has a maximum surface particle diameter S A2 (μm), maximum surface particle size S on the opposite side (A1) A1 (μm) satisfies the following formula (3). S A1 / S A2 <0.75 (3)

[0042] The photosensitive element is formed by forming a support film (A) with a maximum surface particle size S on the uncoated surface (S A1 )<Coated surface (S A2 ) achieves high tack and high resolution. From the viewpoint of suitably exhibiting the effects of the present invention, S A1 / S A2 is preferably less than 0.70, more preferably less than 0.60, and even more preferably less than 0.58. A1 / S A2 can be greater than 0.

[0043] The specific method for measuring the maximum surface particle size S will be described in the examples below.

[0044] S A1 and S A2 is not particularly limited as long as it satisfies the above formula (3), but specifically, S A1is preferably 0.01 μm to 1.0 μm, more preferably 0.01 μm to 0.5 μm, very preferably 0.01 μm to 0.3 μm, and very particularly preferably 0.01 μm to 0.2 μm. S A2 The thickness is preferably 1.0 μm to 10 μm, more preferably 1.0 μm to 8 μm, very preferably 1.0 μm to 5 μm, and very, very preferably 1.0 μm to 3 μm.

[0045] When any one of the developed area ratio Sdr, the number of surface particles P, and the maximum surface particle diameter size S is measured in the support film (A), if there is a location that satisfies the condition of any one of formulas (1) to (3) specified in a specific aspect of the present embodiment, the photosensitive element is included in the photosensitive element according to the specific aspect. In other words, even if the specified condition (any one of formulas (1) to (3)) is not satisfied when measured at a certain location, if the specified condition is satisfied when measured at another location, the photosensitive element is included in the photosensitive element according to the specific aspect.

[0046] <Photosensitive resin composition layer (B)> The photosensitive resin composition layer (B) is laminated on the support film (A). A known photosensitive resin composition layer may be used as the photosensitive resin composition layer (B) according to this embodiment. Typically, the photosensitive resin composition layer is formed from a photosensitive resin composition containing the following components: (i) an alkali-soluble polymer, (ii) an ethylenically unsaturated double bond-containing component (e.g., an ethylenically unsaturated addition-polymerizable monomer), and (iii) a photopolymerization initiator.

[0047] The alkali-soluble polymer of component (i) preferably has a carboxyl group from the viewpoint of alkali solubility, and also preferably has an aromatic group in its side chain from the viewpoint of the strength of the cured film and the coatability of the photosensitive resin composition.

[0048] In the photosensitive element of this embodiment, the photosensitive resin layer (B) preferably contains (i) a comonomer having an aromatic ring in the alkali-soluble polymer in an amount of 50% or more, more preferably 60% or more. As described above, when the photosensitive resin layer (B) contains a large amount of an alkali-soluble polymer component containing an aromatic ring, low tackiness tends to become a problem, and therefore the effects of the present invention are enhanced. As the structure having an aromatic ring, styrene is preferred.

[0049] The acid equivalent of the alkali-soluble polymer is preferably 100 or more from the viewpoint of the development resistance of the photosensitive resin composition layer, and the development resistance, resolution, and adhesion of the resist pattern, and is preferably 600 or less, more preferably 250 to 550, and even more preferably 300 to 500, from the viewpoint of the developability and strippability of the photosensitive resin composition layer.

[0050] The weight-average molecular weight of the alkali-soluble polymer is preferably within the range of 5,000 to 500,000, more preferably 10,000 to 200,000, and even more preferably 18,000 to 100,000, from the viewpoints of maintaining a uniform thickness of the dry film resist and obtaining resistance to the developer. In this specification, the weight-average molecular weight refers to the weight-average molecular weight measured by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene. The dispersity of the alkali-soluble polymer is preferably 1.0 to 6.0.

[0051] Examples of alkali-soluble polymers include carboxylic acid-containing vinyl copolymers and carboxylic acid-containing celluloses.

[0052] The carboxylic acid-containing vinyl copolymer is a compound obtained by vinyl copolymerization of at least one first monomer selected from α,β-unsaturated carboxylic acids and at least one second monomer selected from alkyl (meth)acrylates, hydroxyalkyl (meth)acrylates, (meth)acrylamides and compounds in which the hydrogen on the nitrogen atom is substituted with an alkyl group or an alkoxy group, styrene and styrene derivatives, (meth)acrylonitrile, and glycidyl (meth)acrylate.

[0053] Examples of the first monomer used in the carboxylic acid-containing vinyl copolymer include acrylic acid, methacrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, and maleic acid half esters, and these may be used alone or in combination of two or more.

[0054] The content of the structural units of the first monomer in the carboxylic acid-containing vinyl copolymer is 15% by mass to 40% by mass, preferably 20% by mass to 35% by mass, based on the mass of the copolymer. If the content is less than 15% by mass, development with an alkaline aqueous solution becomes difficult. If the content is more than 40% by mass, the first monomer becomes insoluble in the solvent during polymerization, making it difficult to synthesize the copolymer.

[0055] Specific examples of the second monomer used in the carboxylic acid-containing vinyl copolymer include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, cyclohexyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, (meth)acrylamide, N-methylolacrylamide, N-butoxymethylacrylamide, styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, (meth)acrylonitrile, and glycidyl (meth)acrylate. These may be used alone or in combination of two or more.

[0056] The content of the structural units of the second monomer in the carboxylic acid-containing vinyl copolymer is 60% by mass or more and 85% by mass or less, and preferably 65% ​​by mass or more and 80% by mass or less, based on the mass of the copolymer.

[0057] From the viewpoint of introducing an aromatic group into the side chain, it is more preferable to incorporate structural units of styrene or styrene derivatives such as α-methylstyrene, p-methylstyrene, p-chlorostyrene, etc. as the second monomer into the carboxylic acid-containing vinyl copolymer. In this case, the content of structural units of styrene or styrene derivatives in the carboxylic acid-containing vinyl copolymer is preferably 5% by mass or more and 35% by mass or less, more preferably 15% by mass or more and 30% by mass or less, based on the mass of the copolymer.

[0058] The weight-average molecular weight of the carboxylic acid-containing vinyl copolymer is in the range of 10,000 to 200,000, preferably 18,000 to 100,000. If the weight-average molecular weight is less than 10,000, the strength of the cured film will be low. If the weight-average molecular weight is more than 200,000, the viscosity of the photosensitive resin composition will be too high, resulting in poor coatability.

[0059] The carboxylic acid-containing vinyl copolymer is preferably synthesized by adding an appropriate amount of a radical polymerization initiator such as benzoyl peroxide or azoisobutyronitrile to a solution obtained by diluting a mixture of various monomers with a solvent such as acetone, methyl ethyl ketone, or isopropanol, and then heating and stirring the mixture. The synthesis may also be carried out by adding a portion of the mixture dropwise to the reaction solution. After the reaction is complete, additional solvent may be added to adjust the concentration to the desired level. In addition to solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization may also be used as synthesis methods.

[0060] Examples of carboxylic acid-containing cellulose include cellulose acetate phthalate and hydroxyethyl carboxymethyl cellulose. The content of the alkali-soluble polymer (A) is preferably 30% by mass or more and 80% by mass or less, more preferably 40% by mass or more and 65% by mass or less, based on the total mass of the photosensitive resin composition. If this content is less than 30% by mass, dispersibility in an alkaline developer decreases, resulting in a significantly longer development time. If this content exceeds 80% by mass, photocuring of the photosensitive resin composition layer becomes insufficient, resulting in a decrease in the resistance as a resist. The alkali-soluble polymer may be used alone or in combination of two or more types.

[0061] In the photosensitive element of this embodiment, the ratio of comonomers having an aromatic ring structure in the alkali-soluble polymer in the photosensitive resin layer (B) is preferably 50% or more, more preferably 60% or more. As described above, when the photosensitive resin layer (B) contains a large amount of an alkali-soluble polymer component containing an aromatic ring, low tackiness tends to become a problem, and therefore the effect of the present invention becomes even greater.

[0062] As the ethylenically unsaturated addition polymerizable monomer, component (ii), known compounds can be used.Examples of ethylenically unsaturated addition polymerizable monomers include 2-hydroxy-3-phenoxypropyl acrylate, phenoxytetraethylene glycol acrylate, β-hydroxypropyl-β'-(acryloyloxy)propyl phthalate, 1,4-tetramethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,4-cyclohexanediol di(meth)acrylate, heptapropylene glycol di(meth)acrylate, glycerol (meth)acrylate, 2-di(p-hydroxypropyl) ... Diphenyl)propane di(meth)acrylate, glycerol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, polyoxypropyl trimethylolpropane tri(meth)acrylate, polyoxyethyl trimethylolpropane tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane triglycidyl ether tri(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate Examples of the bisphenol A (meth)acrylate include bisphenol A-based (meth)acrylic acid ester monomers containing an ethylene oxide chain in their molecule, bisphenol A-based (meth)acrylic acid ester monomers containing a propylene oxide chain in their molecule, and bisphenol A-based (meth)acrylic acid ester monomers containing both an ethylene oxide chain and a propylene oxide chain in their molecule.

[0063] Further, as the ethylenically unsaturated addition polymerizable monomer, a urethane compound of a polyisocyanate compound such as hexamethylene diisocyanate or toluylene diisocyanate with a hydroxyacrylate compound such as 2-hydroxypropyl (meth)acrylate, oligoethylene glycol mono(meth)acrylate or oligopropylene glycol mono(meth)acrylate can also be used. These ethylenically unsaturated addition polymerizable monomers can be used alone or in combination of two or more.

[0064] The content of the ethylenically unsaturated addition-polymerizable monomer is preferably 20% by mass to 70% by mass, more preferably 30% by mass to 60% by mass, based on the total mass of the photosensitive resin composition. If this content is less than 20% by mass, the photosensitive resin will not cure sufficiently, resulting in insufficient strength as a resist. On the other hand, if this content exceeds 70% by mass, when the photosensitive element is stored in a roll, edge fusion, in which the photosensitive resin composition layer or the photosensitive resin composition gradually protrudes from the edge of the roll, is likely to occur.

[0065] Examples of the photopolymerization initiator as component (iii) include aromatic ketones such as benzyl dimethyl ketal, benzyl diethyl ketal, benzyl dipropyl ketal, benzyl diphenyl ketal, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin phenyl ether, thioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diisopropylthioxanthone, 2-fluorothioxanthone, 4-fluorothioxanthone, 2-chlorothioxanthone, 4-chlorothioxanthone, 1-chloro-4-propoxythioxanthone, benzophenone, 4,4'-bis(dimethylamino)benzophenone [Michler's ketone], 4,4'-bis(diethylamino)benzophenone, and 2,2-dimethoxy-2-phenylacetophenone; anthracenes such as 9,10-diethoxyanthracene, 9,10-dibutoxyanthracene, and 9,10-diphenylanthracene; aromatic initiators such as α,α-dimethoxy-α-morpholino-methylthiophenylacetophenone and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; N-arylamino acids such as phenylglycine and N-phenylglycine; oxime esters such as 1-phenyl-1,2-propanedione-2-o-benzoyloxime and 2,3-dioxo-3-phenylpropionic acid ethyl-2-(o-benzoylcarbonyl)-oxime; p-dimethylaminobenzoic acid, p-diethylaminobenzoic acid, and p-diisopropylaminobenzoic acid, and esters thereof with alcohols, and p-hydroxybenzoic acid esters. Among these, a combination of 2-(o-chlorophenyl)-4,5-diphenylimidazolyl dimer and Michler's ketone or 4,4'-(diethylamino)benzophenone is preferred.

[0066] The content of the photopolymerization initiator is preferably 0.01% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 10% by mass or less, based on the total mass of the photosensitive resin composition. If this content is less than 0.01% by mass, the sensitivity is insufficient. If this content exceeds 20% by mass, the ultraviolet absorption rate increases, and the bottom part of the photosensitive resin composition layer is insufficiently cured.

[0067] To improve the thermal stability and / or storage stability of the photosensitive resin composition layer (B) according to this embodiment, it is preferable to incorporate a radical polymerization inhibitor into the photosensitive resin composition or the photosensitive resin composition layer. Examples of radical polymerization inhibitors include p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, t-butylcatechol, cuprous chloride, 2,6-di-t-butyl-p-cresol, 2,2'-methylenebis(4-ethyl-6-t-butylphenol), and 2,2'-methylenebis(4-methyl-6-t-butylphenol).

[0068] In this embodiment, the photosensitive resin composition layer (B) may contain a coloring substance such as a dye or a pigment, etc. Examples of the coloring substance include fuchsine, phthalocyanine green, auramine base, chalcoxide green S, paramagenta, crystal violet, methyl orange, Nile blue 2B, Victoria blue, malachite green, basic blue 20, and diamond green.

[0069] In this embodiment, the photosensitive resin composition layer (B) may contain a color-forming dye that develops color upon exposure to light. Examples of known color-forming dyes include a combination of a leuco dye and a halogen compound. Examples of leuco dyes include tris(4-dimethylamino-2-methylphenyl)methane (leuco crystal violet) and tris(4-dimethylamino-2-methylphenyl)methane (leucomalachite green). Examples of halogen compounds include amyl bromide, isoamyl bromide, isobutylene bromide, ethylene bromide, diphenylmethyl bromide, benzal bromide, methylene bromide, tribromomethylphenyl sulfone, carbon tetrabromide, tris(2,3-dibromopropyl)phosphate, trichloroacetamide, amyl iodide, isobutyl iodide, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, and hexachloroethane.

[0070] In this embodiment, if necessary, additives such as plasticizers may be contained in the photosensitive resin composition layer (B). Examples of additives include phthalate esters such as diethyl phthalate, o-toluenesulfonic acid amide, p-toluenesulfonic acid amide, tributyl citrate, triethyl citrate, triethyl acetyl citrate, tri-n-propyl acetyl citrate, tri-n-butyl acetyl citrate, polypropylene glycol, polyethylene glycol, polyethylene glycol alkyl ether, and polypropylene glycol alkyl ether.

[0071] The thickness of the photosensitive resin composition layer (B) is preferably 3 to 400 μm, and more preferably an upper limit of 300, 200, 100, or 50 μm. As the thickness of the photosensitive resin layer approaches 3 μm, the resolution improves, and as the thickness approaches 400 μm, the film strength improves, so the thickness can be appropriately selected depending on the application.

[0072] <Protective film (C)> The protective film (C) is laminated on the photosensitive resin composition layer (B) side of the laminate of the support film (A) and the photosensitive resin composition layer (B), and functions as a cover.

[0073] The protective film (C) can be easily peeled off from the photosensitive resin composition layer (B) because the adhesive strength of the protective film (C) is sufficiently smaller than that of the support film (A). For example, polyethylene film, polypropylene film, oriented polypropylene film, polyester film, etc. can be preferably used as the protective film (C), and it is more preferable that at least the surface of the protective film (C) is made of a polypropylene resin. The thickness of the protective film (C) is preferably 10 to 100 μm, more preferably 10 to 50 μm. Examples of such films include EM-501, E-200, E-201F, FG-201, and MA-411 manufactured by Oji F-Tex Co., Ltd., KW37, 2578, 2548, 2500, and YM17S manufactured by Toray Industries, Inc., and GF-18, GF-818, and GF-858 manufactured by Tamapoly Co., Ltd.

[0074] <Method for forming a resist pattern> The method for forming a resist pattern using a photosensitive element according to this embodiment includes the following steps: a lamination step in which the photosensitive element is laminated to a substrate; an exposure step of exposing the photosensitive resin composition layer of the photosensitive element; and a developing step of developing and removing the unexposed portion of the photosensitive resin composition layer; Preferably, in this order.

[0075] Specifically, in the laminating step, after peeling the protective film (C) from the photosensitive element, the photosensitive resin composition layer is heat-pressurized and bonded to the surface of a support (e.g., a substrate) using a laminator, and laminated once or multiple times. Examples of materials for the substrate include copper, stainless steel (SUS), glass, and indium tin oxide (ITO). The heating temperature during lamination is generally 40°C to 160°C. Heat-pressurization can be performed using a two-stage laminator equipped with two rolls, or by repeatedly passing the laminate of the substrate and the photosensitive resin composition layer through the rolls several times.

[0076] In the exposure step, the photosensitive resin layer is exposed to actinic light using an exposure machine. The exposure can be performed after peeling off the support, if desired. When exposure is performed through a photomask, the exposure dose is determined by the illuminance of the light source and the exposure time, and may be measured using an actinometer. In the exposure step, direct imaging exposure may be performed. In direct imaging exposure, a photomask is not used, and exposure is performed directly on the substrate using a drawing device. A semiconductor laser or an ultra-high pressure mercury lamp with a wavelength of 350 nm to 410 nm is used as the light source, but a light source with a wavelength of 405 nm or less is preferably used. When the drawing pattern is controlled by a computer, the exposure dose is determined by the illuminance of the exposure light source and the moving speed of the substrate.

[0077] The light irradiation method used in the exposure step is preferably at least one method selected from the group consisting of projection exposure, proximity exposure, contact exposure, direct imaging exposure, and electron beam direct writing, and more preferably projection exposure. To improve adhesion, heating may be performed after exposure, and in the heating step, the exposed photosensitive resin is heated (post-exposure heating). The heating temperature is preferably 30°C to 150°C, more preferably 60°C to 120°C. By performing this heating step, resolution and adhesion are improved. Examples of heating methods that can be used include hot air, infrared rays, far-infrared rays, a thermostatic oven, a hot plate, a hot air dryer, an infrared dryer, and hot rolls. Hot rolls are preferred as the heating method, as they enable processing in a short time, and two or more hot rolls are more preferred. The time elapsed from exposure to heating, or more specifically, the time elapsed from the point at which exposure is stopped to the point at which temperature rise begins, is preferably within 15 minutes, or within 10 minutes. The time elapsed from the point at which exposure is stopped to the point at which temperature increase begins may be 10 seconds or more, 20 seconds or more, 30 seconds or more, 1 minute or more, 2 minutes or more, 3 minutes or more, 4 minutes or more, or 5 minutes or more.

[0078] In the development step, the unexposed or exposed areas of the photosensitive resin composition layer after exposure are removed with a developer using a developing device. If a support film is present on the photosensitive resin composition layer after exposure, it is removed. Then, the unexposed or exposed areas are developed and removed using a developer consisting of an alkaline aqueous solution to obtain a resist image.

[0079] The alkaline aqueous solution is preferably an aqueous solution of Na2CO3, K2CO3, or the like. The alkaline aqueous solution is selected according to the properties of the photosensitive resin composition layer, but an aqueous Na2CO3 solution with a concentration of 0.2% by mass to 2% by mass is generally used. The alkaline aqueous solution may contain a surfactant, an antifoaming agent, a small amount of an organic solvent to promote development, etc. The temperature of the developer in the development step is preferably kept constant within the range of 20°C to 40°C.

[0080] A resist pattern can be obtained by the above steps, but if desired, a heating step can be further carried out at 60°C to 300°C. By carrying out this heating step, the chemical resistance of the resist pattern can be improved. For the heating step, a heating furnace using hot air, infrared rays, or far infrared rays can be used.

[0081] <Method for forming conductive patterns (plating patterns)> To obtain a conductive pattern, a conductive pattern forming step may be carried out after the developing step or heating step, in which the substrate on which the resist pattern has been formed is etched or plated.

[0082] The method for producing a conductor pattern is carried out, for example, by using a metal plate or a metal-coated insulating plate as a substrate, forming a resist pattern by the above-mentioned resist pattern formation method, and then carrying out a conductor pattern formation step, in which a conductor pattern is formed on the substrate surface (e.g., copper surface) exposed by development using a known etching method or plating method.

[0083] In one embodiment, a conductor pattern (plating pattern) can be formed using the photosensitive element. In one embodiment, the photosensitive element can be laminated to a copper substrate having a copper seed layer with a thickness of t (um). The copper substrate, for example, has a copper seed layer on its surface. In one embodiment, the method for forming a plating pattern comprises: For photosensitive elements laminated to copper substrates, (1) Exposure using an exposure mask with an X (μm) pitch between exposed and unexposed areas (2) Formation of lines / spaces in the photosensitive resin layer by development after exposure When I did Average space width D W1 is equal to or greater than {((X / 2)±10%)+t}, (3) Formation of plating patterns by plating the above spaces (4) Peeling off the photosensitive resin layer from the substrate When I did Average plating pattern width P W1 However, the average space width D W1 The accuracy is within ±10% of the above.

[0084] The copper substrate is, for example, an electroless copper-plated substrate in which a copper seed layer having a thickness of t (um) is formed on an insulating film. The pitch X of the exposure mask used in the exposure (1) above is the repeating unit of a set of exposed and unexposed areas. Therefore, when the lengths of the exposed and unexposed areas are approximately the same, the widths of the exposed and unexposed areas are approximately (X / 2). Taking into account an error of about ±10% and taking into account the future etching of the copper seed layer (thickness tum), the average space width D after development (2) above is W1 is preferably equal to or greater than {(±10% of (X / 2)+t}. Thereafter, the average plating pattern width P obtained through the above (3) and (4) is W1 is the average space width after development D W1When plating is applied to the spaces in the lines / spaces of the photosensitive resin layer, theoretically the space width and the plating pattern width will match. On the other hand, the plating pattern may press the lines of the photosensitive resin layer during plating, or the lines of the photosensitive resin layer may temporarily swell during plating, narrowing the spaces, etc., and this may result in the plating average pattern width P W1 However, the average space width D W1 In this case, the average plating pattern width P W1 , the average space width D W1 It is preferable to control the difference within ±10% of the above value, and such control is easily achieved by using the above-mentioned photosensitive element.

[0085] Average space width D W1 , and the average plating pattern width P W1 can be obtained, for example, by selecting any number of locations (e.g., 50, 30, or 20 locations) on an image taken with an optical microscope and calculating the average width at those locations.

[0086] The plating treatment in (3) above is, for example, a treatment by electrolytic copper plating. In one embodiment, electrolytic plating can be performed by immersing a substrate on which a line / space (e.g., L / S=5 / 5) of a photosensitive resin layer is formed in a solution containing a mixture of copper sulfate, sulfuric acid, concentrated hydrochloric acid, etc. The electrolytic plating conditions are, for example, a bath temperature of 25°C, a current density of 1.0 A / dm 2 The plating time is 20 minutes. The copper thickness can be confirmed using a known thickness meter. After electrolytic plating, in (4), the dry film can be stripped using an aqueous solution that is more alkaline than the developer, for example, a 3% sodium hydroxide solution at 50°C. The alkaline aqueous solution used for stripping (hereinafter also referred to as the "stripper") is not particularly limited, but an aqueous solution of NaOH or KOH with a concentration of 2% by mass to 5% by mass, or an organic amine stripper is generally used. A small amount of a water-soluble solvent may be added to the stripper. Examples of the water-soluble solvent include alcohol. The temperature of the stripper in the stripping step is preferably within the range of 40°C to 70°C.

[0087] In one embodiment, in the method for forming a wiring pattern, after the step (4), (5) Formation of a post-etching plating pattern that remains after etching the copper seed layer on the substrate after peeling off the photosensitive resin layer. When I did Average plating pattern width after etching F W1 is the average plating pattern width P W1 is smaller than. That is, the average plating pattern width P W1 However, in anticipation of this decrease, the average plating pattern width after etching F W1 This allows the final average plating pattern width after etching, F W1 However, this method can be easily realized by using the photosensitive element. Average plating pattern width P W1 can be obtained, for example, by selecting any number of locations (e.g., 50, 30, or 20 locations) on an image taken with an optical microscope and calculating the average width at those locations.

[0088] In the above-mentioned etching (flash etching) (5), the copper seed layer can be removed using a predetermined etching solution, such as, but not limited to, a mixed etching solution of sulfuric acid and hydrogen peroxide (manufactured by Ebara Densan Co., Ltd.).

[0089] In this embodiment, the photosensitive element or a roll thereof can be used in the manufacture of printed wiring boards; the manufacture of lead frames for mounting IC chips; precision processing of metal foils such as the manufacture of metal masks; the manufacture of packages such as ball grid arrays (BGAs) and chip-sized packages (CSPs); the manufacture of tape substrates such as chip-on-film (COFs) and tape automated bonding (TABs); the manufacture of semiconductor bumps; and the manufacture of partition walls for flat panel displays such as ITO electrodes, address electrodes, and electromagnetic wave shields. Unless otherwise specified, the values ​​of the above-mentioned parameters are measured in accordance with the measurement methods in the examples described below.

[0090] [Embodiment 2] In one embodiment, the photosensitive element comprises: A photosensitive element capable of being laminated to a copper substrate having a copper seed layer with an average thickness of 1 um or less, For the photosensitive element laminated to a copper substrate, (1) Exposure using an exposure mask with a 10 μm pitch between exposed and unexposed areas (2) Formation of lines / spaces in the photosensitive resin layer by development after the exposure. When you do Average space width D W1 and the minimum space width D W2 Toga 1.00 <D W1 / D W2 <1.10 A photosensitive element that satisfies this relationship has little wobble in the sidewalls of the photosensitive resin pattern, making it easy to form a highly accurate wiring pattern. From the same perspective as above, D W1 / D W2is preferably 1.09 or less, more preferably 1.08 or less. The photosensitive element used here can be the photosensitive element described in the first embodiment, which makes it easy to achieve the above relationship.

[0091] Also, in one embodiment, the photosensitive element comprises: A photosensitive element capable of being laminated to a copper substrate having a copper seed layer with an average thickness of 1 um or less, For the photosensitive element laminated to a copper substrate, (1) Exposure using an exposure mask with a 10 μm pitch between exposed and unexposed areas (2) Formation of lines / spaces in the photosensitive resin layer by development after the exposure. (3) Forming a plating pattern by plating the space. (4) Peeling off the photosensitive resin layer from the substrate When you do Average plating pattern width P W1 and the minimum plating pattern width P W2 Toga 1.00 <P W1 / P W2 <1.10 A photosensitive element that satisfies this relationship has little wobble in the sidewalls of the plating pattern, making it easy to form a highly accurate wiring pattern. From the same perspective as above, P W1 / P W2 is preferably 1.09 or less, more preferably 1.08 or less. The photosensitive element used here can be the photosensitive element described in the first embodiment, which makes it easy to achieve the above relationship.

[0092] Further, in one embodiment, the photosensitive element comprises: A photosensitive element capable of being laminated to a copper substrate having a copper seed layer with an average thickness of 1 um or less, For the photosensitive element laminated to a copper substrate, (1) Exposure using an exposure mask with a 10 μm pitch between exposed and unexposed areas (2) Formation of lines / spaces in the photosensitive resin layer by development after the exposure. (3) Forming a plating pattern by plating the space. (4) Peeling off the photosensitive resin layer from the substrate (5) Formation of a post-etching plating pattern that remains after etching the substrate after the peeling of the plating pattern. When you do Average plating pattern width after etching F W1 and the minimum plating pattern width after etching F W2 Toga 1.00 <F W1 / F W2 <1.10 A photosensitive element that satisfies this relationship has little wobble in the sidewalls of the plating pattern after etching, making it easy to form a highly accurate wiring pattern. From the same perspective as above, F W1 / F W2 is preferably 1.09 or less, more preferably 1.08 or less. The photosensitive element used here can be the photosensitive element described in the first embodiment, which makes it easy to achieve the above relationship.

[0093] The photosensitive element according to this embodiment can also achieve the same effects as the photosensitive element according to embodiment 1, and as described above, it is easy to form a highly accurate wiring pattern. [Example]

[0094] Next, the present embodiment will be described in more detail with reference to examples and comparative examples. However, the present embodiment is not limited to the following examples as long as they do not deviate from the gist of the present invention.

[0095] The evaluation samples were prepared as follows. <Preparation of Photosensitive Element> The components shown in Table 1 below (where the number for each component indicates the amount (parts by mass) of solid content) and methyl ethyl ketone measured to give a solid content concentration of 55% were thoroughly stirred and mixed to obtain a photosensitive resin composition preparation. Details of the components shown in Table 1 are shown in Table 2.

[0096] As the support film (A), polyethylene terephthalate (PET) films with a width of 300 mm and different surface shapes shown in Tables 3 to 5 below were used. The PET film was used with the particle type, size, concentration, and particle size distribution adjusted, and with coating or plasma treatment applied to any surface. Details of the films shown in Tables 3 to 5 are shown in Table 6. A solution of the photosensitive resin composition preparation shown in Tables 1 and 2 was applied to the surface of the support film (A) and dried with hot air at 90°C for 1.5 minutes to form a photosensitive resin composition layer (B). At this time, the thickness of the photosensitive resin composition layer (B) after heating was adjusted to 15 μm. Furthermore, a protective film (C) was laminated to the surface of the photosensitive resin composition layer on the side not laminated with the support film (A), to obtain a photosensitive element.

[0097] <Substrate> As an evaluation substrate for image quality, S'PERFLEX (manufactured by Sumitomo Metal Mining Co., Ltd.) prepared by sputter copper plating was used. The substrate used for evaluating plating properties was a copper-clad laminate laminated with an insulating film, ABF-GX92 (manufactured by Ajinomoto Fine-Tech Co., Inc.), which was then desmeared and electroless copper plated (a copper seed layer with a thickness of 1 μm was formed). The substrate surface roughness was adjusted to Ra = 0.4 to 0.3 μm by adjusting the swelling temperature in the desmear process.

[0098] <Lamination> While peeling off the protective film (C) of the photosensitive element, the photosensitive element was laminated onto an evaluation substrate preheated to 50°C using a hot roll laminator (AL-700, manufactured by Asahi Kasei Corporation) at a roll temperature of 105°C, thereby obtaining a photosensitive element laminate. The air pressure was 0.35 MPa, and the lamination speed was 1.5 m / min.

[0099] <Exposure> Two hours after lamination, the support film surface of the photosensitive element laminate was exposed to monochromatic i-line (365 nm) light using a segmented projection exposure system (UX2003 SM-MS04 manufactured by Ushio Inc., using an i-line bandpass filter). A chrome glass photomask containing a line / space (L / S) = 7 / 7 and L / S = 5 / 5 design was used, and exposure was carried out at an exposure dose that would yield the minimum resolution of each photosensitive element.

[0100] In Example 7, exposure was performed using a direct writing exposure device (Paragon-Ultra100, manufactured by Orbotech Corporation, light source peak wavelength: 355 nm) with exposure data including a pattern of L / S=7 / 7, at an exposure dose that provided the minimum resolution. In Example 8, exposure was performed using a direct imaging exposure device (IP-8 M8000H manufactured by ADTEC Engineering, light source peak wavelength: 405 nm) with exposure data including a pattern of L / S=7 / 7, at an exposure dose that provided the minimum resolution. In Example 9, exposure was performed using an exposure machine equipped with an ultra-high pressure mercury lamp (parallel light exposure machine (Oak Manufacturing Co., Ltd., parallel light EXM-1201)) with a chrome glass photomask containing designs of L / S = 7 / 7 and L / S = 5 / 5, at an exposure dose that provided the minimum resolution.

[0101] <PEB:Post Exposure Bake> After exposure, the substrate was heated in a hot air oven preheated to 60° C. for 1 minute.

[0102] <Developing> After peeling off the support film (A) of the photosensitive element laminate, development was carried out by spraying a 1% by mass Na2CO3 aqueous solution at 30°C for a predetermined time using an alkaline developer (Fuji Kiko Co., Ltd., dry film developer). The development spray time was twice the shortest development time, and the post-development water spray time was twice the shortest development time. In this case, the shortest development time was defined as the time required for the unexposed portions of the photosensitive resin layer to completely dissolve.

[0103] [Table 1]

[0104] [Table 2]

[0105] The obtained samples were evaluated as follows. <Number of surface particles P> A laser microscope (OLS4100 manufactured by Olympus) was used to extract particles from any surface of the support film (A) peeled from the prepared photosensitive element within a 258 μm × 260 μm field of view under the following settings, and the average number of surface particles of 1.0 μm or more per four measurements was calculated. Measurement conditions: Objective lens x50 Measurement range: 258 μm x 260 μm Measurement mode: Particle analysis (threshold: 13%, small particle removal: 5, hole filling: 20)

[0106] <Maximum surface particle size S> For any surface of the support film (A) peeled from the prepared photosensitive element, a laser microscope (OLS4100 manufactured by Olympus) was used to extract particles from a field of view of 258 μm × 260 μm under the following settings, and the average value of the maximum surface particle size was calculated for four measurements. Measurement conditions: Objective lens x50 Measurement range: 258 μm x 260 μm Measurement mode: Particle analysis (threshold: 13%, small particle removal: 5, hole filling: 20)

[0107] <Developed area ratio Sdr> The surface roughness of any surface of the support film (A) peeled from the prepared photosensitive element was measured using a scanning white light interference microscope (VS1800 manufactured by Hitachi High-Technologies) based on the method specified in ISO 25178. Measurement conditions: Objective lens x 50, intermediate lens x 1, high-resolution camera Measurement range: 112 μm x 112 μm Measurement mode: WAVE Surface correction: 4th order surface correction

[0108] <Film adhesive strength> A photosensitive element was laminated onto a 1.2 mm thick copper-clad laminate, and the sample was then conditioned for one day at 23°C and 50% RT. Using a Tensilon test method based on JIS Z 0237:2009, the support film (A) was peeled off from the photosensitive resin layer (B) in a 180° direction at a pulling speed of 100 mm / min. The average value, excluding the maximum and minimum values, of five measurements was then evaluated according to the following criteria. Possible: Maximum average 4.0gf or more Unacceptable: Maximum average less than 4.0gf

[0109] <Number of resist side protrusions> Using a scanning electron microscope (Hitachi High-Tech S-3400), the number of protrusions and chips (0.4 μm or larger) on the side of the resist was counted within a 90 μm × 70 μm field of view for a theoretical L / S = 7 / 7 resist pattern after development, and judged according to the following criteria. Excellent: 0~10 pieces Good: 10~100 pieces Possible: 100~300 pieces Not allowed: 300 pieces or more

[0110] <Electrolytic copper plating> The developed substrate with L / S=5 / 5 formed was immersed in an electrolytic copper plating bath (copper sulfate 70 g / L, sulfuric acid 270 g / L, concentrated hydrochloric acid 50 ppm, and a small amount of additives) at a bath temperature of 25°C and a current density of 1.0 A / dm 2 Electrolytic plating was performed at 40°C for 20 minutes. This formed a plating pattern. A thickness gauge was used to confirm that the copper plating had a thickness of 12 μm, and the dry film was then peeled off from the substrate using a 3% sodium hydroxide solution at 50°C.

[0111] <Flash etching> The copper seed layer (1 μm thick) was removed by flash etching using a sulfuric acid / hydrogen peroxide mixed etching solution (manufactured by Ebara Densan Co., Ltd.), thereby forming a post-etching plating pattern.

[0112] <Space / pattern width measurement> After development, the resist pattern (theoretically L / S=5 / 5) was measured at 50 arbitrary points in a 90 μm × 70 μm field of view using an optical microscope (Nikon Lv100Nd), and the average space width D W1 and minimum space width D W2 was calculated. After electrolytic copper plating, the dry film was peeled off from the plating pattern (theoretically L / S=5 / 5), and the average plating pattern width P W1 and minimum plating pattern width P W2 was calculated. After flash etching, the post-etching plating pattern (theoretically L / S=4 / 6) was measured using the same method to determine the post-etching plating average pattern width F W1 and the minimum plating pattern width after etching F W2 was calculated.

[0113] The evaluation results are shown in the table below.

[0114] [Table 3]

[0115] [Table 4]

[0116] [Table 5]

[0117] [Table 6]

[0118] It was found that in the examples that satisfied the above-mentioned formulas (1) to (3), high film adhesive strength (high tackiness) and a small number of protrusions on the side surfaces of the resist (excellent resolution) were obtained.

[0119] On the other hand, if any of the formulas (1) to (3) is not satisfied, that is, if Sdr A1 / Sdr A2 ≥ 0.75, P A1 / P A2 ≥ 0.75, S A1 / S A2 When the value was ≧0.75, the tackiness and resolution were reduced.

[0120] Although the embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the invention. [Industrial Applicability]

[0121] By using the photosensitive element of the present invention, both high tack and high resolution can be achieved, and it can be widely used as a dry film resist in forming resist patterns.

Claims

1. A photosensitive element having a support film (A) and a photosensitive resin composition layer (B) in this order, The developed area ratio Sdr of the interface of the support film (A) on the side opposite to the side in contact with the photosensitive resin composition layer (B), as defined in ISO 25178 A1 (%)but, Sdr A1 <0.005 (%) A photosensitive element comprising:

2. A photosensitive element having a support film (A) and a photosensitive resin composition layer (B) in this order, The developed area ratio Sdr of the interface of the support film (A) on the side in contact with the photosensitive resin composition layer (B), as defined in ISO 25178 A2 (%), the developed area ratio of the opposite interface Sdr A1 (%) is expressed by the following formula (1): Sdr A1 / Sdr A2 <0.75 (1) A photosensitive element characterized by satisfying the above.

3. A photosensitive element having a support film (A) and a photosensitive resin composition layer (B) in this order, The number P of surface particles of 1.0 μm or more contained in an area of ​​258 μm×260 μm on the surface of the support film (A) in contact with the photosensitive resin composition layer (B) A2 (pieces), the number of surface particles on the opposite side P A1 (pieces) are represented by the following formula (2): P A1 / P A2 <0.75 (2) A photosensitive element characterized by satisfying the above.

4. A photosensitive element having a support film (A) and a photosensitive resin composition layer (B) in this order, The maximum surface particle diameter size S of the surface of the support film (A) on the side in contact with the photosensitive resin composition layer (B) A2 (μm), maximum surface particle size S on the opposite surface A1 (μm) is expressed by the following formula (3): S A1 / S A2 <0.75 (3) A photosensitive element characterized by satisfying the above.

5. 5. The photosensitive element according to claim 1, wherein in the photosensitive resin composition layer (B), the ratio of comonomers having an aromatic ring structure in the binder is 50% or more.

6. The photosensitive element of claim 5 , wherein the structure having an aromatic ring is styrene.

7. The following steps: a lamination step of laminating the photosensitive element of any one of claims 1 to 6 onto a substrate; 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; The method for forming a resist pattern, wherein the exposure step is carried out by a projection exposure method.

8. The following steps: a lamination step of laminating the photosensitive element of any one of claims 1 to 6 onto a substrate; 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; The method for forming a resist pattern, wherein the exposure step is carried out with an exposure wavelength of 405 nm or less.

9. The photosensitive element can be laminated to a copper substrate having a copper seed layer with an average thickness of 1 μm or less, For the photosensitive element laminated to the copper substrate, (1) Exposure using an exposure mask with exposed and unexposed areas at a 10 μm pitch (2) Formation of lines and spaces in the photosensitive resin layer by development after the exposure. When you do Average space width D Ｗ１ and the minimum space width D Ｗ２ Toga 1.00<D Ｗ１ / D Ｗ２ <1.10 The photosensitive element of claim 1 , wherein the following relationship is satisfied:

10. The photosensitive element can be laminated to a copper substrate having a copper seed layer with an average thickness of 1 μm or less, (1) Exposure using an exposure mask with exposed and unexposed areas at a 10 μm pitch (2) Formation of lines and spaces in the photosensitive resin layer by development after the exposure. (3) Forming a plating pattern by plating the space. (4) Peeling off the photosensitive resin layer from the substrate When you do Average plating pattern width P Ｗ１ and the minimum plating pattern width P Ｗ２ Toga 1.00<P Ｗ１ / P Ｗ２ <1.10 The photosensitive element of claim 1 , wherein the following relationship is satisfied:

11. The photosensitive element can be laminated to a copper substrate having a copper seed layer with an average thickness of 1 μm or less, (1) Exposure using an exposure mask with exposed and unexposed areas at a 10 μm pitch (2) Formation of lines and spaces in the photosensitive resin layer by development after the exposure. (3) Forming a plating pattern by plating the space. (4) Peeling off the photosensitive resin layer from the substrate (5) Formation of a post-etching plating pattern remaining after etching the copper seed layer on the substrate after the peeling. When you do Average plating pattern width after etching F Ｗ１ and the minimum plating pattern width after etching F Ｗ２ Toga 1.00<F Ｗ１ / F Ｗ２ <1.10 The photosensitive element of claim 1 , wherein the following relationship is satisfied:

12. A method for forming a conductor pattern using the photosensitive element according to any one of claims 1 to 6, comprising the steps of: the photosensitive element can be laminated to a copper substrate having a copper seed layer of thickness t (um); For the photosensitive element laminated to the copper substrate, (1) Exposure using an exposure mask with an X (μm) pitch between exposed and unexposed areas (2) Formation of lines and spaces in the photosensitive resin layer by development after the exposure. When I did Average space width D Ｗ１ is equal to or greater than {(±10% of (X / 2) + t}, (3) Forming a plating pattern by plating the space. (4) Peeling off the photosensitive resin layer from the substrate When I did Average plating pattern width P Ｗ１ However, the average space width D Ｗ１ A method for forming a conductive pattern, wherein the difference is within ±10% of the above.

13. After the method for forming a conductive pattern according to claim 12, (5) Formation of a post-etching plating pattern remaining after etching the copper seed layer on the substrate after the peeling. When I did Average plating pattern width after etching F Ｗ１ is the average plating pattern width P Ｗ１ A method for forming a wiring pattern that is smaller than the above.

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