Photosensitive element and method for forming a 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] Printed circuit boards (PCBs) are used in electronic devices such as personal computers and mobile phones for mounting components or semiconductors. Conventionally, a photosensitive element (photosensitive resin laminate), also known as a dry film resist, has been used as a resist for the manufacture of printed circuit boards, etc., which consists of a photosensitive resin composition layer laminated on a support film, and a protective film laminated on the photosensitive resin composition layer as needed.

[0003] In such photosensitive elements, the exposure process for curing the photosensitive layer is carried out via a support film, so the properties of the support film have a significant impact on the resolution. For this reason, a film with few lubricants that block the light being exposed or internal foreign matter is preferably used as the support film (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 [Overview of the project] [Problems that the invention aims to solve]

[0005] As printed circuit board wiring achieves higher resolution, the composition and amount of compounds in the photosensitive resin composition have also been investigated. In recent years, compositions containing a large amount of styrene as a comonomer component in the alkali-soluble polymer that forms the photosensitive resin layer have become preferred. Styrene-based alkali-soluble polymers are essential components for high resolution because they do not swell easily during alkali development, but their low tack, which results in low adhesive strength with the support film and makes them prone to detaching from the photosensitive resin layer, is a challenge. With low-tack photosensitive elements, the support film may peel off when the laminated substrate is lifted by the equipment during transport, potentially disrupting production. In order to increase tack, a rougher surface roughness on the surface of the support film that contacts the photosensitive resin layer is advantageous because it increases the adhesive surface area and enhances the anchoring effect (the photosensitive resin layer penetrates the fine irregularities of the support film, improving adhesion).

[0006] On the other hand, in recent years, the demand for high resolution has increased even further, and a resolution of L / S = 5 / 5 μm or less is now required for the resist after development. In fine resist patterns, it is advantageous for high resolution if the sides of the resist pattern are flat and free of jaggedness, that is, if the straightness of the sidewalls is good, so that they do not come into contact with adjacent patterns. Regarding improving the straightness of the sidewall, studies have been conducted in the past on the composition and amount of compounds in the photosensitive resin composition. While rattle of 1 μm or more has been reduced to some extent, rattle of less than 1 μm has yet to be eliminated.

[0007] There are various factors that contribute to sidewall wobble, one of which is the influence of the support film. Normally, when a photosensitive element is exposed, the photosensitive resin layer is irradiated with active light through the support film. If refraction or scattering of light occurs in the support film, wobble will occur in the photosensitive resin layer. To address this problem, a method is known to improve the straightness of the sidewall without improving the photosensitive element by using an exposure machine with a high numerical aperture lens. Because a high numerical aperture lens has a shallow depth of field, the influence of refraction and scattering in the support film can be minimized by focusing only on the photosensitive resin layer. While this method is effective on flat substrates such as wafers and glass substrates, it presents a challenge in copper-clad laminates commonly used in printed circuit boards, where the undulations and irregularities originating from the organic substrate are significant, making the entire substrate prone to defocusing. In areas where defocusing occurs, the resolution and sidewall linearity of the resist pattern deteriorate significantly. Therefore, it is considered difficult to apply exposure machines (especially projection exposure machines) using lenses with a high numerical aperture to organic substrates with significant undulation.

[0008] Therefore, a solution on the material side is preferable, and in order to achieve the high resolution requirements demanded in recent years, a photosensitive element is required that has no rattle of 1 μm or more, as well as no rattle of less than 1 μm in the sidewall.

[0009] This invention has been proposed in view of the above-mentioned conventional circumstances, and the object of this invention is to provide a photosensitive element and a method for forming a resist pattern that achieves 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 ratio of the unfolded area Sdr of the interface between the support film (A) and the photosensitive resin composition layer (B), as defined in ISO 25178. , , A2 , A1 , , , A1 (%) is Sdr A1 <0.005 (%) A photosensitive element characterized in that it is [2] A photosensitive element having a support film (A) and a photosensitive resin composition layer (B) in this order, The spread area ratio Sdr of the interface on the side of the support film (A) in contact with the photosensitive resin composition layer (B) defined by ISO 25178 A2 (%), and the spread area ratio Sdr of the interface on the opposite side A1 (%) satisfies the following formula (1): Sdr A1 / Sdr A2 <0.75 (1) A photosensitive element characterized in that it satisfies [3]<00002\08>A photosensitive element having a support film (A) and a photosensitive resin composition layer (B) in this order, The number of surface particles P of 1.0 μm or more contained in an area of 258 μm × 260 μm on the side of the surface of the support film (A) in contact with the photosensitive resin composition layer (B) A2 (pieces), and the number of surface particles P on the opposite side A1 (pieces) satisfies the following formula (2): P A1 / P A2 <0.75 (2) A photosensitive element characterized in that it satisfies [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 on the side of the support film (A) in contact with the photosensitive resin composition layer (B) A2 (μm), and the maximum surface particle size S of the opposite side A1 (μm) satisfies the following formula (3): S A1 / S A2 <0.75 (3) A photosensitive element characterized in that it satisfies [5] The photosensitive element according to any one of [1] to [4], wherein the photosensitive resin composition layer (B) has a comonomer ratio of aromatic ring structures in the binder of 50% or more. [6] The photosensitive element according to [5], wherein the structure having the aromatic ring is styrene. [7] The following steps: A lamination process for laminating a photosensitive element described in any one of items [1] to [6] onto a substrate; An exposure step of exposing the photosensitive resin layer of the photosensitive element; and A developing step is included in which the unexposed portion of the photosensitive resin layer is developed and removed; A method for forming a resist pattern, wherein the exposure step is performed by a projection exposure method. [8] The following steps: A lamination process for laminating a photosensitive element described in any one of items [1] to [6] onto a substrate; An exposure step of exposing the photosensitive resin layer of the photosensitive element; and A developing step is included in which the unexposed portion of the photosensitive resin layer is developed and removed; A method for forming a resist pattern, wherein the exposure step is performed with an exposure wavelength of 405 nm or less. [9] The photosensitive element, which can be laminated on a copper substrate having a copper seed layer with an average thickness of 1 μm or less, With respect to the photosensitive element laminated on the copper substrate, (1) Exposure using an exposure mask with exposed and unexposed areas at a 10 μm pitch. (2) Formation of lines / spaces in the photosensitive resin layer by development after exposure. When you do this, Average space width D W1 And, minimum space width D W2 Toga 1.00 <D W1 / D W2 <1.10 A photosensitive element described in any one of items [1] to [6] that satisfies the following relationship.

[10] The photosensitive element, which can be laminated on 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 / spaces in the photosensitive resin layer by development after exposure. (3) Formation of a plating pattern by plating the space (4) Detachment of the photosensitive resin layer from the substrate When you do this, Plating average pattern width P W1 And, the minimum plating pattern width P W2 Toga 1.00 <P W1 / P W2 <1.10 A photosensitive element described in any one of items [1] to [6] that satisfies the following relationship.

[11] The photosensitive element, which can be laminated on 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 / spaces in the photosensitive resin layer by development after exposure. (3) Formation of a plating pattern by plating the space (4) Detachment of the photosensitive resin layer from the substrate (5) Formation of post-etched plating patterns that remain after etching the copper seed layer onto the substrate after peeling, among the plating patterns. When you do this, Average pattern width F after etching and plating W1 And, the minimum pattern width F after etching and plating. W2 Toga 1.00 <F W1 / F W2 <1.10 A photosensitive element described in any one of items [1] to [6] that satisfies the following relationship.

[12] A method for forming a conductor pattern using a photosensitive element described in any one of items [1] to [6], The photosensitive element can be laminated on a copper substrate having a copper seed layer of thickness t(um), With respect to the photosensitive element laminated on 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 exposure. When you do this, Average space width D W1 When {((X / 2) ±10%) + t} or greater, (3) Formation of a plating pattern by plating the space (4) Detachment of the photosensitive resin layer from the substrate When you do this, Plating average pattern width P W1 However, the average space width D W1 A method for forming a conductor pattern that is within ±10% of the specified value.

[13] After the method for forming the conductor pattern described in

[12] , (5) Formation of post-etched plating patterns that remain after etching the copper seed layer onto the substrate after peeling, among the plating patterns. When you do this, Average pattern width F after etching and plating W1 However, the average plating pattern width P W1 A method for forming wiring patterns smaller than the specified size. [Effects of the Invention]

[0011] The present invention provides a photosensitive element and a method for forming a resist pattern that achieves high tack and high resolution. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic cross-sectional view showing one example of the configuration of the photosensitive element of the present invention. [Figure 2]Figure 1 schematically illustrates the refraction of the active light rays incident on the support film during exposure to the photosensitive element shown in Figure 1, as they reach the photosensitive resin layer. [Modes for carrying out the invention]

[0013] The embodiments for carrying out the present invention will be described in detail below. In the following explanation, the numerical ranges indicated using "~" include both the upper and lower limits. [Embodiment 1] [Photosensitive element] Figure 1 is a schematic cross-sectional view showing 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 ratio of the unfolded area (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 defined in ISO 25178. A1 (%)but, Szero A1 <0.005(%) It is characterized by being such.

[0014] Furthermore, 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 unfolded area ratio Sdr of the interface (A2) on the side of the support film (A) that contacts the photosensitive resin composition layer (B), as defined in ISO 25178. A2 (%), Sdr of the developed area of ​​the opposite interface (A1) A1 (%) is given by the following formula (1): Szero A1 / Sdr A2 <0.75 (1) It is characterized by satisfying the following conditions.

[0015] Furthermore, 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 of surface particles P larger than 1.0 μm contained in a 258 μm × 260 μm area of ​​the side (A2) of the support film (A) that is in contact with the photosensitive resin composition layer (B). A2 (Number of particles), P of surface particles on the opposite side (A1) A1 (The number of items is given by the following formula (2): P A1 / P A2 <0.75 (2) It is characterized by satisfying the following conditions.

[0016] In this specification, the surface particle count P is defined as the number of particles 1.0 μm or larger contained within a 258 μm × 260 μm area of ​​the support film (A), as determined using a laser microscope.

[0017] Furthermore, 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 size S of the side (A2) of the support film (A) that is in contact with the photosensitive resin composition layer (B). A2 (μm), Maximum surface particle size S on the opposite side (A1) A1 (μm) is given by the following formula (3): S A1 / S A2 <0.75 (3) It is characterized by satisfying the following conditions.

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

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

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

[0021] By reducing the surface roughness of the uncoated surface A1 of the support film (A), rattling of the sidewall can be reduced, enabling high resolution. On the other hand, by increasing the surface roughness of the coated surface A2, the contact area between the support film (A) and the photosensitive resin layer (B) is increased, enhancing the anchoring effect and enabling high tackiness.

[0022] In other words, in the photosensitive element of the present invention, the uncoated surface (Sdr) of the support film (A) is defined as the uncoated surface (Sdr A1 )<Coated surface (Sdr A2 ) or, with respect to the number of surface particles P of the support film (A), the uncoated surface (P A1 )<Coated surface (P A2 ) or, with respect to the maximum surface particle size S of the support film (A), the uncoated surface (S A1 )<Coated surface (S A2 This allows for the achievement of high tack and high resolution.

[0023] Furthermore, if the unfolded area ratio Sdr, the number of surface particles P, or the maximum surface particle diameter size S of the coated surface of the support film (A) is large, the surface irregularities will increase when transferred to the photosensitive resin layer (B), but this does not affect the resolution or the straightness of the sidewalls.

[0024] Conventionally, it has been believed that a smooth coating surface (one side) is sufficient 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. In recent years, many support films (A) with only one side smoothed have been applied to dry film applications. However, the smooth side is applied to the surface in contact with the photosensitive resin layer, and there is no precedent for using the opposite side. In other words, the present invention provides a photosensitive element that achieves high tack and high resolution by coating the surface in the opposite direction to the normal surface.

[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 active light emitted from an exposure light source.

[0026] 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. Polyethylene terephthalate (PET), which has moderate flexibility and strength, is usually preferred.

[0027] Among these, it is preferable to use a high-quality film with fewer internal foreign matter. Specifically, 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 small lubricant diameter and low lubricant content, a PET film containing lubricant on only one side of the film, a thin-film PET film, a PET film with a smoothing treatment applied to at least one side, or a PET film with a roughening treatment such as plasma treatment applied to at least one side. This allows the light to be exposed to 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 internal foreign matter particles with a diameter of 2 μm to 5 μm contained in the support film (A) is 30 particles / 30 mm 2 The following is preferable: 15 pieces / 30mm 2 More preferably, 10 pieces / 30mm 2 The following is even more preferable:

[0029] The titanium (Ti) content in the support film (A) is preferably 1 ppm to 20 ppm, and more preferably 2 ppm to 12 ppm. If the titanium content is 20 ppm or less, the number of internal foreign matter derived from titanium-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. A thinner support film thickness reduces the number of internal foreign matter, thus preventing a decrease in resolution. However, if the thickness is less than 5 μm, stretching deformation in the winding direction due to tension or tearing due to minute scratches may occur during the coating and winding manufacturing process, or the film may lack sufficient strength, resulting in wrinkles during lamination.

[0031] It is preferable that at least one side of the support film (A) is subjected to a smoothing treatment using a calender or the like. This reduces the surface roughness of one side of the support film (A), particularly the side A2 that does not come into contact with the photosensitive resin composition layer (B), thereby improving 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 rays irradiated onto the photosensitive resin composition layer (B) and obtaining higher resolution after exposure and development of the photosensitive element.

[0033] Furthermore, in the photosensitive element of this embodiment, the unfolded area ratio Sdr of the surface (A2) of the support film (A) that is in contact with the photosensitive resin composition layer (B) is defined in ISO 25178. A2 (%), Sdr of the developed area of ​​the opposite side (A1) A1 (%) satisfies the following equation (1). Szero A1 / Sdr A2 <0.75 (1)

[0034] The photosensitive element has a uncoated surface (Sdr) with respect to the undeveloped area ratio Sdr of the support film (A). A1 )<Coated surface (Sdr A2 This results in high tack and high resolution.

[0035] The specific method for measuring the Sdr (surface area ratio) is described in the examples below. From the viewpoint of suitably achieving the effects of the present invention, Sdr A1 / Sdr A2 The value is preferably less than 0.60, more preferably less than 0.55, and even more preferably less than 0.50. A1 / Sdr A2 It's fine if it's greater than 0.

[0036] Szero A1 and Sdr A2While not particularly limited as long as the above equation (1) is satisfied, specifically, Sdr A1 Sdr A1 It is <0.005(%), preferably 0.0005% to 0.004%, more preferably 0.0005% to 0.003%, very preferably 0.0005% to 0.002%, and extremely preferably 0.0005% to 0.001%. Szero A2 The amount is preferably 0.006% to 0.03%, more preferably 0.006% to 0.02%, very preferably 0.006% to 0.01%, and very preferably 0.006% to 0.008%.

[0037] Alternatively, the photosensitive element of this embodiment has a surface particle count of 1.0 μm or larger included in a 258 μm × 260 μm area of ​​the surface (A2) of the support film (A) that is in contact with the photosensitive resin composition layer (B) P A2 (Number of particles), P of surface particles on the opposite side (A1) A1 (The number) satisfies the following equation (2). P A1 / P A2 <0.75 (2)

[0038] The photosensitive element has a number of surface particles P on the support film (A) and an uncoated surface (P A1 )<Coated surface (P A2 This results in high tack and high resolution.

[0039] The specific method for measuring the surface particle number P is described in the examples below.

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

[0041] Alternatively, for the photosensitive element of the present embodiment, the maximum surface particle size S A2 (μm) of the surface (A2) on the side in contact with the photosensitive resin composition layer of the support film (A) and the maximum surface particle size S A1 (μm) of the opposite surface (A1) satisfy the following formula (3). S A1 / S A2 <0.75 (3)

[0042] For the photosensitive element, with respect to the maximum surface particle size S of the support film (A), the non-coated surface (S A1 ) < the coated surface (S A2 ), high tackiness and high resolution are achieved. From the viewpoint of preferably achieving the effects of the present invention, S A1 / S A2 is preferably less than 0.70, more preferably less than 0.60, and still more preferably less than 0.58. S A1 / S A2 may be greater than 0.

[0043] Regarding the specific measurement method of the maximum surface particle size S, it is described in the examples below.

[0044] S A1 and S A2 are not particularly limited as long as they satisfy the above formula (3). Specifically, S A1The particle size is 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 extremely preferably 0.01 μm to 0.2 μm. S A2 The particle size 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 extremely preferably 1.0 μm to 3 μm.

[0045] Furthermore, if any of the developed area ratio Sdr, surface particle count P, and maximum surface particle diameter size S are measured in the support film (A), and any of the conditions of formulas (1) to (3) specified in a particular embodiment of this embodiment are met at any location, the photosensitive element is included in the photosensitive element relating to that particular embodiment. In other words, even if the specified conditions (any of formulas (1) to (3)) are not met when measured at a certain location, if the specified conditions are met when measured at another location, that photosensitive element is included in the photosensitive element relating to that particular embodiment.

[0046] <Photosensitive resin composition layer (B)> The photosensitive resin composition layer (B) is laminated on the support film (A). As the photosensitive resin composition layer (B) according to this embodiment, a known photosensitive resin composition layer may be used. Typically, the photosensitive resin composition layer is formed from a photosensitive resin composition comprising 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] (i) The alkali-soluble polymer component 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, in the photosensitive resin layer (B), (i) the proportion of comonomers having an aromatic ring of an alkali-soluble polymer is preferably 50% or more, and more preferably 60% or more. As described above, when the photosensitive resin layer (B) contains a large amount of alkali-soluble polymer components containing aromatic rings, low tackiness tends to be a problem, and therefore the effects of the present invention become even more pronounced. Styrene is preferred as the structure having aromatic rings.

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

[0050] The weight-average molecular weight of the alkali-soluble polymer is preferably in 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 viewpoint 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 using a calibration curve of standard polystyrene by gel permeation chromatography (GPC). The degree of dispersion 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 cellulose.

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

[0053] Examples of primary monomers used in carboxylic acid-containing vinyl copolymers include acrylic acid, methacrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, and maleic acid semi-esters, which may be used individually or in combination of two or more.

[0054] The content of the constituent units of the first monomer in the carboxylic acid-containing vinyl copolymer is 15% by mass or more and 40% by mass or less, preferably 20% by mass or more and 35% by mass or less, 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 exceeds 40% by mass, the first monomer becomes insoluble in the solvent during polymerization, making the synthesis of the copolymer difficult.

[0055] Specific examples of secondary monomers used in carboxylic acid-containing vinyl copolymers 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, which may be used individually or in combination of two or more.

[0056] The content of the constituent units of the second monomer in the carboxylic acid-containing vinyl copolymer is 60% by mass or more and 85% by mass or less, 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 aromatic groups into the side chains, it is more preferable to include styrene or a styrene derivative such as α-methylstyrene, p-methylstyrene, or p-chlorostyrene as a secondary monomer in the carboxylic acid-containing vinyl copolymer. In this case, the content ratio of the styrene or styrene derivative constituent unit in the carboxylic acid-containing vinyl copolymer is preferably 5% by mass or more and 35% by mass or less, and 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 in the range of 18,000 to 100,000. If this weight-average molecular weight is less than 10,000, the strength of the cured film will be low. If this weight-average molecular weight exceeds 200,000, the viscosity of the photosensitive resin composition will become too high, and its coating properties will decrease.

[0059] Carboxylic acid-containing vinyl copolymers are 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. In some cases, the mixture may be synthesized by adding a portion of it dropwise to the reaction solution. After the reaction is complete, the solvent may be further added to adjust the concentration to the desired level. In addition to solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization can also be used as synthesis methods.

[0060] Examples of carboxylic acid-containing cellulose include cellulose acetate phthalate and hydroxyethyl carboxymethylcellulose. The content of alkali-soluble polymer (A) is preferably 30% to 80% by mass, more preferably 40% to 65% by mass, based on the total mass of the photosensitive resin composition. If the content is less than 30% by mass, the dispersibility in the alkaline developer decreases and the development time becomes significantly longer. If the content exceeds 80% by mass, the photocuring of the photosensitive resin composition layer becomes insufficient and the resistance as a resist decreases. 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 proportion of comonomers having an aromatic ring of an alkali-soluble polymer in the photosensitive resin layer (B) is preferably 50% or more, and more preferably 60% or more. As described above, when the photosensitive resin layer (B) contains a large amount of alkali-soluble polymer components including aromatic rings, low tackiness tends to be a problem, and therefore the effects of the present invention become even more pronounced.

[0062] (ii) As the ethylenically unsaturated addition polymerizable monomer that is component, any known type of compound 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, and 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 include diallyl phthalate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 4-n-octylphenoxypentapropylene glycol acrylate, bis(triethylene glycol methacrylate)nonapropylene glycol, bis(tetraethylene glycol methacrylate)polypropylene glycol, bis(triethylene glycol methacrylate)polypropylene glycol, bis(diethylene glycol acrylate)polypropylene glycol, 4-n-nylnonylphenoxyheptaethylene glycol dipropylene glycol (meth)acrylate, phenoxytetrapropylene glycol tetraethylene glycol (meth)acrylate, compounds containing an ethylene oxide chain in the molecule of a bisphenol A-based (meth)acrylic acid ester monomer, compounds containing a propylene oxide chain in the molecule of a bisphenol A-based (meth)acrylic acid ester monomer, and compounds containing both an ethylene oxide chain and a propylene oxide chain in the molecule of a bisphenol A-based (meth)acrylic acid ester monomer.

[0063] Furthermore, as ethylenically unsaturated addition polymerizable monomers, urethane compounds of polyhydric isocyanate compounds such as hexamethylene diisocyanate and toluene diisocyanate and hydroxyacrylate compounds such as 2-hydroxypropyl (meth)acrylate, oligoethylene glycol mono(meth)acrylate, and oligopropylene glycol mono(meth)acrylate can also be used. These ethylenically unsaturated addition polymerizable monomers may be used individually or in combination of two or more.

[0064] The content of ethylenically unsaturated addition polymerizable monomers is preferably 20% to 70% by mass, and more preferably 30% to 60% by mass, based on the total mass of the photosensitive resin composition. If the content is less than 20% by mass, the photosensitive resin will not cure sufficiently, and the strength as a resist will be insufficient. On the other hand, if the content exceeds 70% by mass, when the photosensitive element is stored in a roll shape, the photosensitive resin composition layer or the photosensitive resin composition itself will gradually protrude from the roll end face, i.e., edge fusion is likely to occur.

[0065] (iii) Examples of photopolymerization initiators that are components include aromatic ketones such as benzyldimethyl 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; 2-(o-chloro Examples include biimidazole compounds such as lophenyl)-4,5-diphenylimidazolyl dimer; acridines such as 9-phenylacridine; 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-aryl amino acids such as phenylglycine and N-phenylglycine; oxime esters such as 1-phenyl-1,2-propanedione-2-o-benzoyloxime and 2,3-dioxo-3-phenylpropionate ethyl-2-(o-benzoylcarbonyl)-oxime; and p-dimethylaminobenzoic acid, p-diethylaminobenzoic acid, and p-diisopropylaminobenzoic acid and their esters with alcohols, and p-hydroxybenzoic acid esters. Among these, a combination of 2-(o-chlorophenyl)-4,5-diphenylimidazolyl dimer and Michla'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, and more preferably 1% by mass or more and 10% by mass or less, based on the total mass of the photosensitive resin composition. If the content is less than 0.01% by mass, the sensitivity will not be sufficient. If the content exceeds 20% by mass, the ultraviolet absorption rate will increase, and the curing of the bottom portion of the photosensitive resin composition layer will be insufficient.

[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 include a radical polymerization inhibitor in 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 coloring substances such as dyes and pigments. Examples of coloring substances include fuchsin, 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, a color-developing dye that develops color upon light irradiation may be included in the photosensitive resin composition layer (B). As color-developing dyes, for example, combinations of leuco dyes and halogen compounds are known. Examples of leuco dyes include tris(4-dimethylamino-2-methylphenyl)methane [leucocrystal 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, tribromomethylphenylsulfone, 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, additives such as plasticizers may be included in the photosensitive resin composition layer (B) as needed. Examples of additives include phthalate esters such as diethyl phthalate, o-toluenesulfonamide, p-toluenesulfonamide, 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, with more preferable upper limits of 300, 200, 100, or 50 μm. The closer the thickness of the photosensitive resin layer is to 3 μm, the better the resolution, and the closer it is to 400 μm, the better the film strength; therefore, it 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 because its adhesion to the photosensitive resin composition layer (B) is significantly weaker than that of the support film (A). For example, polyethylene film, polypropylene film, stretched 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 polypropylene resin. The thickness of the protective film (C) is preferably 10 to 100 μm, and more preferably 10 to 50 μm. Examples include EM-501, E-200, E-201F, FG-201, MA-411 from Oji F-Tex Co., Ltd., KW37, 2578, 2548, 2500, YM17S from Toray Industries, Inc., and GF-18, GF-818, GF-858 from Tamapoly Co., Ltd.

[0074] <Method for forming a resist pattern> The method for forming a resist pattern using the photosensitive element according to this embodiment involves the following steps: A lamination process for stacking photosensitive elements onto a substrate; An exposure step for exposing the photosensitive resin composition layer of a photosensitive element; and A developing process for developing and removing unexposed areas of a photosensitive resin composition layer; The following are preferably included in this order:

[0075] In the lamination process, specifically, after peeling off the protective film (C) from the photosensitive element, the photosensitive resin composition layer is heat-pressed onto the surface of a support (e.g., a substrate) using a laminator, and laminated once or multiple times. Examples of substrate materials include copper, stainless steel (SUS), glass, and indium tin oxide (ITO). The heating temperature during lamination is generally 40°C to 160°C. Heat pressing 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 process, the photosensitive resin layer is exposed to active light using an exposure machine. Exposure can be performed after peeling off the support if desired. When exposure is performed through a photomask, the exposure amount is determined by the illuminance of the light source and the exposure time, and may be measured using a light meter. Direct imaging exposure may also be performed in the exposure process. In direct imaging exposure, a photomask is not used, and exposure is performed directly on the substrate using a drawing device. A semiconductor laser with a wavelength of 350 nm to 410 nm or an ultra-high pressure mercury lamp is used as the light source, but it is preferable to use a light source with a wavelength of 405 nm or less. When the drawing pattern is controlled by a computer, the exposure amount 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 process is preferably at least one method selected from projection exposure, proximity exposure, contact exposure, direct imaging exposure, and electron beam direct writing, and projection exposure is more preferable. To improve adhesion, heating may be performed after exposure, in which 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. Performing this heating process improves resolution and adhesion. As for the heating method, hot air, infrared rays, far infrared rays, a constant temperature bath, a hot plate, a hot air dryer, an infrared dryer, or a hot roll can be used. The heating method is preferably a hot roll because it can be processed in a short time, and two or more hot rolls are more preferable. The elapsed time from exposure to heating, or more precisely, the elapsed time from the time exposure is stopped to the time heating is started, is preferably within 15 minutes or within 10 minutes. The elapsed time from the point when exposure is stopped to the point when the temperature rise 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 developing process, unexposed or exposed areas of the photosensitive resin composition layer after exposure are removed using a developing device and a developing solution. If there is a support film on the photosensitive resin composition layer after exposure, it is removed. Subsequently, the unexposed or exposed areas are developed and removed using a developing solution consisting of an alkaline aqueous solution to obtain a resist image.

[0079] As the alkaline aqueous solution, aqueous solutions of Na2CO3, K2CO3, etc. are preferred. The alkaline aqueous solution is selected according to the properties of the photosensitive resin composition layer, but an aqueous solution of Na2CO3 with a concentration of 0.2% to 2% by mass is generally used. Surface surfactants, defoamers, small amounts of organic solvents to promote development may be mixed into the alkaline aqueous solution. The temperature of the developer solution during the development process is preferably kept constant within the range of 20°C to 40°C.

[0080] The resist pattern is obtained through the above process, but if desired, a further heating process can be performed at 60°C to 300°C. This heating process can improve the chemical resistance of the resist pattern. A heating furnace using hot air, infrared rays, or far-infrared rays can be used for the heating process.

[0081] <Method for forming a conductor pattern (plating pattern)> To obtain a conductor pattern, a conductor pattern formation step may be performed after the development step or heating step, in which the substrate on which the resist pattern has been formed is etched or plated.

[0082] The method for manufacturing a conductor pattern involves, for example, using a metal plate or a metal film insulating plate as a substrate, forming a resist pattern using the resist pattern formation method described above, and then proceeding through a conductor pattern formation step. In the conductor pattern formation step, 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 aspect, the conductor pattern (plating pattern) can be formed using the photosensitive element. In one aspect, the photosensitive element can be laminated on a copper substrate having a copper seed layer with a thickness t (μm). The copper substrate has, for example, a copper seed layer on its surface. And in one aspect, in the method for forming the plating pattern, with respect to the photosensitive element laminated on the copper substrate, (1) Exposure using an exposure mask with an X (μm) pitch for the exposed portion and the unexposed portion <000\0552>(2) Formation of line / space of the photosensitive resin layer by development after exposure When performing, the average space width D W1 is {((±10% of X / 2)+t} or more, (3) Formation of the plating pattern by plating treatment into the above space (4) Peeling of the photosensitive resin layer from the substrate When performing, the average plating pattern width P W1 is within ±10% of the average space width D W1 (3) The average plating pattern width P

[0084] The copper substrate is, for example, an electroless copper plating substrate in which a copper seed layer with a thickness t (μm) is formed on an insulating film. The pitch X of the exposure mask used in the above (1) exposure is a set of repeating units of the exposed portion and the unexposed portion. Therefore, when the lengths of the exposed portion and the unexposed portion are substantially the same, the widths of the exposed portion and the unexposed portion are approximately (X / 2) respectively. Considering an error of about ±10% and also taking into account the future etching of the copper seed layer (thickness t μm), the average space width D W1 after the above (2) development is preferably {((±10% of X / 2)+t} or more. >After that, the average plating pattern width P W1 obtained through the above (3) and (4) W1It is within ±10% of that. When plating is applied to the space in the line / space of the photosensitive resin layer, theoretically, the space width and the plating pattern width should match. On the other hand, during plating, the plating pattern presses against the line of the photosensitive resin layer, or the line of the photosensitive resin layer temporarily swells during plating, causing the space to narrow, etc., which affects the average plating pattern width P W1 However, the average space width D W1 The average plating pattern width P may increase or decrease. W1 The average space width D W1 It is preferable to control the value within ±10% of the specified range. 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 This can be obtained, for example, by selecting any number of locations (e.g., 50, 30, or 20) on an image taken with an optical microscope and calculating the average width of those locations.

[0086] The plating process in (3) above is, for example, 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 has been formed in a solution of copper sulfate, sulfuric acid, and concentrated hydrochloric acid. The electrolytic plating conditions are, for example, a bath temperature of 25°C and a current density of 1.0 A / dm². 2 The plating time is 20 minutes. The copper thickness can be confirmed with a known thickness gauge. After electroplating, in (4), the dry film can be peeled off with an aqueous solution that is more alkaline than the developer, for example, a 3% sodium hydroxide solution at 50°C. The alkaline aqueous solution for peeling (hereinafter also referred to as "peeling solution") is not particularly limited, but an aqueous solution of NaOH or KOH with a concentration of 2% to 5% by mass, or an organic amine-based peeling solution is generally used. A small amount of water-soluble solvent may be added to the peeling solution. Examples of water-soluble solvents include alcohol. The temperature of the peeling solution in the peeling process is preferably in the range of 40°C to 70°C.

[0087] In one embodiment, the method for forming a wiring pattern involves, after (4) above, (5) Formation of post-etched plating patterns, which remain after the etching of the copper seed layer on the substrate after the photosensitive resin layer has been removed. When you do this, Average pattern width F after etching and plating W1 However, the average plating pattern width P W1 It is smaller than that. In other words, the plating average pattern width P is affected by the etching of the copper seed layer. W1 Although it decreases, the average pattern width F after etching is taken into account to account for this decrease. W1 This allows for the design of the resulting average pattern width F after etching. W1 However, this method results in higher accuracy. This technique is easily implemented by using the photosensitive element described above. Plating average pattern width P W1 This can be obtained, for example, by selecting any number of locations (e.g., 50, 30, or 20) on an image taken with an optical microscope and calculating the average width of those locations.

[0088] In the etching (flash etching) described in (5) above, the copper seed layer can be removed with a predetermined etching solution. Examples of etching solutions include, but are not limited to, a mixed etching solution of sulfuric acid and hydrogen peroxide (manufactured by Ebara Electric Industries, Ltd.).

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

[0090] [Embodiment 2] In one embodiment, the photosensitive element is A photosensitive element that can be laminated on a copper substrate having a copper seed layer with an average thickness of 1 μm or less, For the above photosensitive element laminated on a copper substrate, (1) Exposure using an exposure mask with exposed and unexposed areas at a 10 μm pitch. (2) Formation of lines / spaces in the photosensitive resin layer by development after exposure. When you do this, Average space width D W1 And, minimum space width D W2 Toga 1.00 <D W1 / D W2 <1.10 The following relationship is satisfied. Photosensitive elements that can satisfy this relationship have less play in the sidewalls of the photosensitive resin pattern, making it easier to manufacture high-precision wiring patterns. From the same perspective as above, D W1 / D W2Preferably, the value is 1.09 or less, and more preferably 1.08 or less. The photosensitive element used here can be the photosensitive element described in Embodiment 1, which makes it easier to achieve the above relationship.

[0091] In one embodiment, the photosensitive element is A photosensitive element that can be laminated on a copper substrate having a copper seed layer with an average thickness of 1 μm or less, For the above photosensitive element laminated on a copper substrate, (1) Exposure using an exposure mask with exposed and unexposed areas at a 10 μm pitch. (2) Formation of lines / spaces in the photosensitive resin layer by development after exposure. (3) Formation of a plating pattern by plating the space (4) Detachment of the photosensitive resin layer from the substrate When you do this, Plating average pattern width P W1 And, the minimum plating pattern width P W2 Toga 1.00 <P W1 / P W2 <1.10 The following relationship is satisfied. Photosensitive elements that can satisfy this relationship have less play in the sidewalls of the plating pattern, making it easier to manufacture high-precision wiring patterns. From the same perspective as above, P W1 / P W2 Preferably, the value is 1.09 or less, and more preferably 1.08 or less. The photosensitive element used here can be the photosensitive element described in Embodiment 1, which makes it easier to achieve the above relationship.

[0092] Furthermore, in one embodiment, the photosensitive element is A photosensitive element that can be laminated on a copper substrate having a copper seed layer with an average thickness of 1 μm or less, For the above photosensitive element laminated on a copper substrate, (1) Exposure using an exposure mask with exposed and unexposed areas at a 10 μm pitch. (2) Formation of lines / spaces in the photosensitive resin layer by development after exposure. (3) Formation of a plating pattern by plating the space (4) Detachment of the photosensitive resin layer from the substrate (5) Formation of the post-etched plating pattern that remains after etching the substrate after peeling off the plating pattern When you do this, Average pattern width F after etching and plating W1 And, the minimum pattern width F after etching and plating. W2 Toga 1.00 <F W1 / F W2 <1.10 The following relationship is satisfied. Photosensitive elements that can satisfy this relationship have less sidewall rattle in the plated pattern after etching, making it easier to create high-precision wiring patterns. From the same perspective as above, F W1 / F W2 Preferably, the value is 1.09 or less, and more preferably 1.08 or less. The photosensitive element used here can be the photosensitive element described in Embodiment 1, which makes it easier to achieve the above relationship.

[0093] The photosensitive element according to this embodiment can also obtain the effects obtained with the photosensitive element according to Embodiment 1, and as described above, it is easy to manufacture highly accurate wiring patterns. [Examples]

[0094] Next, this embodiment will be described in more detail with reference to examples and comparative examples. However, this embodiment is not limited to the following examples, unless it deviates from its essence.

[0095] The evaluation samples were prepared as follows. <Fabrication of photosensitive elements> The components shown in Table 1 below (where the numbers for each component indicate the amount (parts by mass) as solid content) and methyl ethyl ketone, weighed to a solid content concentration of 55%, were thoroughly stirred and mixed to obtain a photosensitive resin composition solution. Details of the components shown in Table 1 are shown in Table 2.

[0096] As the support film (A), polyethylene terephthalate (PET) films with different surface shapes and a width of 300 mm, as shown in Tables 3 to 5 below, were used. The PET films used were materials in which the type, size, concentration, and particle size distribution of added particles were adjusted, and coating or plasma treatment was applied to any desired 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 set to 15 μm. Furthermore, a protective film (C) was laminated onto the surface of the photosensitive resin composition layer on the side where the support film (A) was not laminated to obtain a photosensitive element.

[0097] <Circuit board> S'PERFLEX (manufactured by Sumitomo Metal Mining Co., Ltd.), fabricated by sputter copper plating, was used as the evaluation substrate for image quality. As a substrate for evaluating plating properties, a copper-clad laminate was laminated with ABF-GX92 (manufactured by Ajinomoto Finetech Co., Ltd.) as an insulating film, and then subjected to desmear and electroless copper plating (forming a copper seed layer with a copper thickness of 1 μm). The surface roughness of the substrate was adjusted to Ra = 0.4 to 0.3 μm by controlling the swelling temperature during the desmear process.

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

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

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

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

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

[0103] [Table 1]

[0104] [Table 2]

[0105] The obtained samples were evaluated as follows: <Number of surface particles P> Using a laser microscope (Olympus OLS4100), the average number of surface particles 1.0 μm or larger per four measurements was calculated from particles extracted from any surface of the support film (A) peeled off from the fabricated photosensitive element, within a 258 μm × 260 μm field of view, using the following settings. Measurement conditions: Objective lens x50 Measurement range: 258 μm × 260 μm Measurement mode: Particle analysis (Threshold: 13%, Small particle removal: 5, Gap filling: 20)

[0106] <Maximum surface particle size S> Using a laser microscope (Olympus OLS4100), the average value of the maximum surface particle size per four measurements was calculated from particles extracted from any surface of the support film (A) peeled off from the fabricated photosensitive element, within a 258 μm × 260 μm field of view, using the following settings. Measurement conditions: Objective lens x50 Measurement range: 258 μm × 260 μm Measurement mode: Particle analysis (Threshold: 13%, Small particle removal: 5, Gap filling: 20)

[0107] <Developed area ratio Sdr> Surface roughness was measured on any surface of the support film (A) peeled off from the fabricated photosensitive element using a scanning white light interference microscope (Hitachi High-Tech VS1800) based on the method specified in ISO 25178. Measurement conditions: Objective lens x50, intermediate lens x1, high-resolution camera. Measurement range: 112 μm × 112 μm Measurement mode: WAVE Surface correction: 4th-order surface correction

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

[0109] <Number of side protrusions in the resist> Using a scanning electron microscope (Hitachi High-Tech S-3400), the number of protrusions and defects (0.4 μm or larger) on the side surface of the resist in a 90 μm × 70 μm field of view for a theoretically L / S = 7 / 7 resist pattern after development was counted 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> A developed substrate with an L / S=5 / 5 coating was immersed in an electrolytic copper plating bath (70 g / L copper sulfate, 270 g / L sulfuric acid, 50 ppm concentrated hydrochloric acid, trace amounts of additives), at a bath temperature of 25°C and a current density of 1.0 A / dm². 2 Electroplating was performed for 20 minutes. This formed a plating pattern. The thickness of the copper plating was confirmed to be 12 μm using a thickness gauge, and the dry film was peeled off 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 Electric Industries, Ltd.). This formed a post-etched plating pattern.

[0112] <Space / Pattern Width Measurement> After development, the resist pattern (theoretically L / S=5 / 5) was measured at 50 arbitrary points within a 90μm × 70μm field of view using an optical microscope (Nikon Lv100Nd), and the average space width D was measured. W1 and minimum space width D W2 The result was calculated. After electrolytic copper plating, the dry film was removed from the plated pattern (theoretically L / S=5 / 5), and the average plated pattern width P was measured using the same method. W1 Plating minimum pattern width P W2 The result was calculated. After flash etching, the post-etched plating pattern (theoretically L / S=4 / 6) is measured using the same measurement method to obtain the average post-etched plating pattern width F. W1 and the minimum pattern width F after etching and plating W2 The result 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] In the embodiments satisfying equations (1) to (3) described above, it was found that the film exhibited both high adhesive strength (high tackiness) and a small number of resist side protrusions (excellent resolution).

[0119] In contrast, if any of equations (1) to (3) are not satisfied, that is, Sdr A1 / Sdr A2 ≥0.75, P A1 / P A2 ≥0.75, S A1 / S A2 When the value was ≥0.75, tackiness and resolution decreased.

[0120] 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. [Industrial applicability]

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

Claims

1. A photosensitive element having a support film (A) and a photosensitive resin composition layer (B) in this order, The maximum surface particle size S of the side of the support film (A) that is in contact with the photosensitive resin composition layer (B). A2 (μm), maximum surface particle size S on the opposite side A1 (μm) is given by the following formula (3): S A1 / S A2 ≦0.33 (3) Satisfying the conditions, The number of surface particles P A2 (particles) of 1.0 μm or larger contained in a 258 μm × 260 μm area on the side of the support film (A) that is in contact with the photosensitive resin composition layer (B), and the number of surface particles P A1 (particles) on the opposite side, are given by the following formula (2): Satisfying P A1 / P A2 ≤ 0.13, According to ISO 25178, the unfolded area ratio Sdr A2 (%) of the side of the support film (A) that is in contact with the photosensitive resin composition layer (B), and the unfolded area ratio Sdr A1 (%) of the opposite side, respectively, Sdr A1 <0.005(%) 0.006(%)≦Sdr A2≦0.03(%) A photosensitive element characterized by satisfying the following conditions.

2. The ratio of the unfolded area of ​​the interface on the side of the support film (A) that is in contact with the photosensitive resin composition layer (B), as defined in ISO 25178, Sdr A2 (%), Sdr of the developed area ratio of the opposite interface A1 (%) is given by the following formula (1): Sdr A1 / Sdr A2 <0.75 (1) A photosensitive element according to claim 1, satisfying the following conditions.

3. The following steps: A lamination step of laminating the photosensitive element according to claim 1 or 2 onto a substrate; An exposure step of exposing the photosensitive resin layer of the photosensitive element; and A developing step is included in which the unexposed portion of the photosensitive resin layer is developed and removed; A method for forming a resist pattern, wherein the exposure step is performed by a projection exposure method.

4. The following steps: A lamination step of laminating the photosensitive element according to claim 1 or 2 onto a substrate; An exposure step of exposing the photosensitive resin layer of the photosensitive element; and A developing step is included in which the unexposed portion of the photosensitive resin layer is developed and removed; A method for forming a resist pattern, wherein the exposure step is performed with an exposure wavelength of 405 nm or less.

5. The photosensitive element, which can be laminated on a copper substrate having a copper seed layer with an average thickness of 1 μm or less, With respect to the photosensitive element laminated on the copper substrate, (1) Exposure using an exposure mask with exposed and unexposed areas at a 10 μm pitch. (2) Formation of lines / spaces in the photosensitive resin layer by development after exposure. When you do this, Average space width D W1 and the minimum space width D W2 are 1.00<D W1 / D W2 <1.10 A photosensitive element according to claim 1 or 2 that satisfies the relationship.

6. The photosensitive element, which can be laminated on 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 / spaces in the photosensitive resin layer by development after exposure. (3) Formation of a plating pattern by plating the space (4) Detachment of the photosensitive resin layer from the substrate When you do this, 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 according to claim 1 or 2 that satisfies the relationship.

7. The photosensitive element, which can be laminated on 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 / spaces in the photosensitive resin layer by development after exposure. (3) Formation of a plating pattern by plating the space (4) Detachment of the photosensitive resin layer from the substrate (5) Formation of a post-etched plating pattern that remains after etching the copper seed layer onto the substrate after peeling, among the plating patterns. When you do this, Average pattern width F after etching and plating W1 And, the minimum pattern width F after etching and plating. W2 Toga 1.00<F W1 / F W2 <1.10 A photosensitive element according to claim 1 or 2 that satisfies the relationship.

8. A method for forming a conductor pattern using a photosensitive element according to claim 1 or 2, The photosensitive element can be laminated on a copper substrate having a copper seed layer with a thickness t (μm), With respect to the photosensitive element laminated on 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 exposure. When you do this, Average space width D W1 When {(±10% of (X / 2) + t)} or greater, (3) Formation of a plating pattern by plating the space (4) Detachment of the photosensitive resin layer from the substrate When you do this, Average plating pattern width P W1 However, the average space width D W1 A method for forming a conductor pattern that is within ±10% of the specified value.

9. After the method for forming the conductor pattern described in claim 8, (5) Formation of a post-etched plating pattern that remains after etching the copper seed layer onto the substrate after peeling, among the plating patterns. When you do this, Average pattern width F after etching and plating W1 However, the average plating pattern width P W1 A method for forming wiring patterns smaller than the specified size.

Images