Biaxially oriented laminated polyester film

Abstract

Provided are: a polyester film which has excellent resist coating properties and sliding properties over a large area, and which is capable of suppressing the occurrence of irregularities on the wall surface of a fine resist pattern, thereby having few defects in a polyester film production process and being easy to handle; disclosed is a biaxially oriented laminated polyester film which is capable of reproducing a dry film resist that can satisfactorily obtain a resist pattern having high resolution at a high yield. A biaxially oriented laminated polyester film for use as a dry film resist support, which is characterized by satisfying the following (1) to (4). (1) The laminated polyester film has a slippery resin layer (X) and a base material layer, the base material layer is composed of at least two layers including a layer A and a layer B, the layer A has a film surface (A), and the layer B has a film surface (B). (2) A slippery resin layer (X) that does not contain particles is laminated on the film surface (A) side. (3) The arithmetic mean roughness SRa (B) of the film surface (B) on the opposite side from the film surface (A) is less than 7 nm. And (4) the values of the static friction coefficients between the easy-to-slip resin layer (X) and the film surface (B) at 10 locations measured per 100 m in the longitudinal direction are all 0.4-0.8 inclusive, and the values of the dynamic friction coefficients are all 0.3-0.7 inclusive.

Description

Technical Field

[0001] The present invention relates to biaxially oriented laminated polyester films. Background Art

[0002] Biaxially oriented laminated polyester films are widely used as transfer materials for ceramic slurries in ceramic capacitor production and dry film resists for printed circuit board circuit formation due to their moderate toughness, thermal stability, smoothness, transparency, and economic efficiency.

[0003] Dry film resists are used to form circuits on printed wiring boards, semiconductor packages, flexible substrates, and the like. Dry film resists are formed by coating a photosensitive layer (photoresist layer) on a polyester film as a support, and then sandwiching the layers with protective films (cover films) such as polyethylene film, polypropylene film, and polyester film.

[0004] When a conductor circuit is produced using this dry film resist, the following steps are generally employed.

[0005] 1) A step of peeling the protective film from the dry film resist and laminating the substrate / conductive base layer so that the exposed resist layer surface is in close contact with the surface of the conductive base layer such as copper foil on the substrate.

[0006] 2) Next, a photomask having a conductor circuit pattern printed thereon is placed on a support made of a polyester film, and a resist layer mainly composed of a photosensitive resin is irradiated with ultraviolet light from above to expose the resist layer.

[0007] 3) After the photomask and the polyester film are peeled off, the unreacted portion of the resist layer is dissolved and removed with a solvent.

[0008] 4) Next, etching is performed using acid or the like to dissolve and remove the exposed portion of the conductive base material layer.

[0009] After step 5), the photoreactive portion in the resist layer and the portion of the conductive base material layer corresponding to the photoreactive portion remain as they are, and then, through a step of removing the remaining resist layer, a conductor circuit is formed on the substrate.

[0010] The polyester film used as a support is required to have transparency to efficiently transmit ultraviolet rays, smoothness to enable coating of a resist with a uniform thickness, and slipperiness to facilitate handling during the production of a dry film resist.

[0011] If the polyester film as a support has poor slip properties, wrinkles and grain-like defects may occur when the polyester film is wound into a roll, and the resist cannot be uniformly applied, which causes a decrease in yield.

[0012] In order to improve the handling and windability of such a polyester film, a method of incorporating particles as a lubricant into the polyester film and forming fine protrusions on the surface of the polyester film has been used.

[0013] However, in recent years, with the miniaturization and lightweighting of IT equipment, there is a demand for polyester films used as dry film resist supports that can realize fine wiring patterns of printed wiring boards with high resolution. During the ultraviolet irradiation during the exposure process, the particles used as lubricants and the protrusions caused by the particles cause scattering and reflection of ultraviolet rays, resulting in reduced resolution of fine wiring and defects.

[0014] Patent Document 1 discloses a polyester film for photoresist having excellent transparency, lubricity, unevenness of the side of the resist pattern, and resolution, few defects, and easy handling by laminating a lubricant resin layer containing no particles having an average particle size greater than 40 nm and having a ten-point average roughness (SRz) of 100 to 700 nm on the side opposite to the resist coating surface.

[0015] In addition, Patent Document 2 proposes a polyester film for dry film resist having a particle-containing layer on its surface containing particles with an average particle size of 0.03 to 0.200 μm at a mass ratio of 10 to 2900 ppm and excluding particles with a particle size of 0.300 μm or greater, wherein the particle-containing surface layer contains particles with an average particle size of 0.005 to 0.150 μm.

[0016] Prior art literature

[0017] Patent Literature

[0018] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-361446

[0019] Patent Document 2: Japanese Patent Application Laid-Open No. 2022-19775 Summary of the Invention

[0020] Problems to be solved by the invention

[0021] However, even these proposals have difficulty in meeting the requirements for higher resolution. Defects such as pattern distortion and omission in the developed resist caused by particles used as lubricants, and poor state of the resist pattern wall surface cannot be fully eliminated, and there is still a demand for improved quality for higher resolution.

[0022] In addition, as a result of reducing the amount of particles added and the size in order to obtain a high-resolution wiring pattern, the yield in the film manufacturing process and the above-mentioned dry film resist manufacturing process is reduced. In particular, when using a polyester film that is continuous in the length direction when being wound into a film roll, if even a portion has poor sliding properties, problems related to the film windability will significantly occur. Therefore, the demand for improved productivity (film windability) must also be met.

[0023] In view of these circumstances, the present invention aims to address the above-mentioned problems associated with substrate films for high-resolution dry film resists and to provide a biaxially oriented laminated polyester film for dry film resists that has excellent resist coating properties and slip properties over a large area, can suppress the generation of irregularities on the wall surfaces of fine resist patterns, has few defects in the polyester film manufacturing process and is easy to operate, and can be used for dry film resists that can produce high-resolution resist patterns at a high yield.

[0024] Means for solving problems

[0025] The present invention has the following features.

[0026] [I] A biaxially oriented laminated polyester film for use as a dry film resist support, characterized in that it satisfies the following (1) to (4).

[0027] (1) A laminated polyester film comprising a lubricant resin layer (X) and a substrate layer, wherein the substrate layer is composed of at least two layers including a layer A and a layer B, the layer A having a film surface (A), and the layer B having a film surface (B).

[0028] (2) A lubricant resin layer (X) containing no particles is laminated on the film surface (A) side.

[0029] (3) The arithmetic mean roughness SRa(B) of the film surface (B) opposite to the film surface (A) is less than 7 nm.

[0030] (4) The static friction coefficient between the lubricant resin layer (X) and the film surface (B) measured at 10 locations every 100 m in the longitudinal direction was 0.4 to 0.8, and the dynamic friction coefficient was 0.3 to 0.7.

[0031] [II] The biaxially oriented laminated polyester film according to [I], wherein the ten-point average surface roughness SRz(X) of the lubricant resin layer (X) and the ten-point average surface roughness SRz(B) of the film surface (B) are both 10 nm or more and 70 nm or less.

[0032] [III] The biaxially oriented laminated polyester film according to [I] or [II], wherein the lubricant resin (X) laminated on the film surface (A) has a midpoint glass transition temperature of 40°C or higher.

[0033] [IV] The biaxially oriented laminated polyester film according to [I], which does not contain particles having a volume average particle size of 0.150 μm or more.

[0034] [V] The biaxially oriented laminated polyester film according to [I], wherein in the above-mentioned A layer, when an area of ​​0.88 cm in the length direction × 1.16 cm in the width direction is observed 10 times by a laser microscope, the number of coarse particles with a long diameter of 15.0 μm or more is 5 or less, the number of coarse particles with a long diameter of 10.0 μm or more and less than 15.0 μm is 30 or less, and the number of coarse particles with a long diameter of 1.0 μm or more and less than 10.0 μm is 1500 or less.

[0035] [VI] According to the biaxially oriented laminated polyester film described in [I], in the C layer without a film surface arranged between the above-mentioned A layer and B layer, when an area of ​​0.88 cm in the length direction × 1.16 cm in the width direction is observed 10 times by a laser microscope, the number of coarse particles with a long diameter of 15.0 μm or more is 5 or less, the number of coarse particles with a long diameter of 10.0 μm or more and less than 15.0 μm is 30 or less, and the number of coarse particles with a long diameter of 1.0 μm or more and less than 10.0 μm is 1500 or less.

[0036] [VII] The biaxially oriented laminated polyester film according to [I], wherein the surface resistivity of the lubricant resin laminated on the film surface (A) is 1.0×10 12 Ω or less.

[0037] Effects of the Invention

[0038] According to the present invention, a biaxially oriented laminated polyester film for dry film resists can be provided which has excellent resist coating properties and sliding properties over a large area and can suppress the occurrence of unevenness on the wall surface of a fine resist pattern. Therefore, the polyester film manufacturing process has few defects and is easy to operate. The film can be used to reproduce a high-resolution resist pattern with good reproduction and high yield. DETAILED DESCRIPTION

[0039] Hereinafter, the present invention will be described in detail with reference to preferred embodiments.

[0040] The biaxially oriented laminated polyester film of the present invention (hereinafter also referred to as a polyester film) requires that the arithmetic mean surface roughness SRa(B) of one surface of the polyester film (this surface is referred to as surface (B)) be less than 7 nm. More preferably, SRa(B) is less than 5 nm. By achieving a surface roughness within this range, the biaxially oriented laminated polyester film of the present invention achieves good smoothness when used as a dry film resist, enabling the formation of a uniform photoresist layer. When SRa(B) is 7 nm or greater, coating omissions and transfer defects may occur when used as a dry film resist, which is unsuitable. The surface roughness of layer B can be adjusted to the above range by incorporating a specific amount of specific organic particles or inorganic particles, described below, into the polyester resin constituting layer B.

[0041] The biaxially oriented laminated polyester film of the present invention preferably has a ten-point average surface roughness SRz(X) of the lubricant resin layer (X) of the polyester film and SRz(B) of the other surface (B) of the film of 10 nm or more and 70 nm or less, more preferably 20 nm or more and 60 nm or less. By achieving a surface roughness within this range, the polyester film of the present invention achieves slip properties with appropriate smoothness when used as a dry film resist, enabling the formation of a uniform photoresist layer. Furthermore, a good coefficient of friction can be consistently achieved over a large area of ​​the polyester film. If SRz(B) exceeds 70 nm, coating omissions and transfer defects may occur when used as a dry film resist. Furthermore, if either SRz(X) or SRz(B) exceeds 70 nm, protrusions on the film surface may be caught, causing an effect such as an anchoring effect to occur, resulting in portions with an increased coefficient of friction, making it impossible to achieve a good coefficient of friction consistently over a large area of ​​the polyester film. Furthermore, if either SRa(X) or SRa(B) is less than 10 nm, air expelling properties may be insufficient when the polyester film is wound into a roll, causing winding misalignment. The surface roughness of layers A and B can be adjusted to the above range by providing a lubricant resin layer, described below, on surface A and by incorporating a specific amount of specific organic or inorganic particles, described below, into the polyester resin constituting the layer having surface B (layer B).

[0042] The biaxially oriented laminated polyester film of the present invention needs to have a static friction coefficient of 0.4 or more and 0.8 or less between the lubricant resin layer (X) and the polyester film surface (B) measured at 10 locations per 100 m in the longitudinal direction, and a dynamic friction coefficient of 0.3 or more and 0.7 or less. By achieving static and dynamic friction coefficients within this range, the polyester film of the present invention can provide good operability over a large area during coating and transfer, and can obtain a resist pattern at a high yield. When the static friction coefficient of 0.8 or the dynamic friction coefficient of 0.7 between the lubricant resin layer (X) and the polyester film surface (B) measured at 10 locations per 100 m in the longitudinal direction exceeds 0.8, or when the dynamic friction coefficient exceeds 0.7, there may be a portion where the operability during coating and transfer deteriorates, and therefore good operability cannot be maintained over a large area of ​​the polyester film, resulting in a reduction in yield. In addition, when the static friction coefficient between the lubricant resin layer (X) and the polyester film surface (B) measured at 10 locations every 100 m in the longitudinal direction is less than 0.4, or when the dynamic friction coefficient is less than 0.3, the slippage may occur when the polyester film is wound into a roll due to excessively good slip properties. In order to achieve the above-mentioned ranges for the static friction coefficient and dynamic friction coefficient between the lubricant resin layer (X) and the polyester film surface (B) measured at 10 locations every 100 m in the longitudinal direction, this can be achieved by providing the lubricant resin layer described later on the A surface and adjusting the surface roughness of the lubricant resin layer (X) and the film surface (B) to be within the above-mentioned ranges.

[0043] From the viewpoint of making the film slippery and also improving the transmittance, the biaxially oriented laminated polyester film of the present invention uses a substrate layer having a laminated structure of more than two layers. When the biaxially oriented laminated polyester film of the present invention has a laminated structure of two layers, it is preferably a laminated structure of two types of two layers of A layer / B layer. If it is a laminated structure of two types of two layers of A layer / B layer, it is easy to give suitable properties to the surface of the easy-slip resin layer (X) (and the film surface (A) of the A layer) and the film surface (B) of the B layer, and therefore it is preferred. In the case of a laminated structure with three layers, it can be a laminated structure of three types of three layers of A layer / C layer / B layer, or other laminated structures. If it is a laminated structure of three types of three layers of A layer / C layer / B layer, it is possible to give suitable properties to the surface of the easy-slip resin layer (X) (and the film surface (A) of the A layer) and the film surface (B) of the B layer, respectively. When a resist layer is laminated on the film surface (B) side, it is used in a manner of performing ultraviolet exposure from the surface side of the easy-slip resin layer (X). When the resist layer is laminated to the cover film and rolled up, the surface of the lubricant resin layer (X) (surface (A)) is in contact with the cover film. The film surface refers to the surface including the longitudinal and width directions of the film.

[0044] The polyester resin constituting the polyester film of the present invention preferably comprises at least 70 mol% of a polyester obtained by polymerizing monomers or oligomers containing dicarboxylic acids, diols, and their ester-forming derivatives as main components. In the present invention, aromatic dicarboxylic acids are preferably used as the dicarboxylic acid.

[0045] Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalene dicarboxylic acid, with terephthalic acid being particularly preferred. These acid components may be used alone or in combination of two or more, or may be partially copolymerized with other aromatic dicarboxylic acids such as isophthalic acid or fatty acids.

[0046] Examples of the diol component include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and neopentyl glycol. Of these, ethylene glycol is preferably used. These diol components may be used alone or in combination of two or more.

[0047] Preferred polyesters used in the biaxially oriented laminated polyester film of the present invention include polyethylene terephthalate, polyethylene naphthalate and copolymers thereof, polybutylene terephthalate and copolymers thereof, polybutylene naphthalate and copolymers thereof, further polyhexamethylene terephthalate and copolymers thereof, polyhexamethylene naphthalate and copolymers thereof, and the like. In particular, polyethylene terephthalate is preferred from the viewpoint of performance and economic efficiency.

[0048] The polyester used in the biaxially oriented laminated polyester film of the present invention can be produced by conventionally known methods. For example, methods can be employed in which an acid component and a diol component are directly subjected to an esterification reaction, and the reaction product is then heated under reduced pressure to remove the remaining diol component while undergoing polycondensation. Methods can also be employed in which a dialkyl ester is used as the acid component, subjected to an ester exchange reaction with the diol component, and then polycondensed in the same manner as described above. In such cases, conventionally known alkali metals, alkaline earth metals, manganese, cobalt, zinc, antimony, germanium, titanium compounds, and the like can be used as reaction catalysts, as needed.

[0049] The intrinsic viscosity of the polyester used in the biaxially oriented laminated polyester film of the present invention is preferably 0.50 dl / g or more and less than 0.80 dl / g, and more preferably 0.55 dl / g or more and less than 0.70 dl / g.

[0050] The biaxially oriented laminated polyester film of the present invention must be biaxially oriented. Biaxial orientation, as used herein, refers to a state where an unstretched (unoriented) film is stretched in two directions using conventional methods (showing a biaxially oriented pattern in wide-angle X-ray diffraction). Stretching can be performed by sequential biaxial stretching or simultaneous biaxial stretching. Sequential biaxial stretching can be performed by performing the stretching steps in the longitudinal (vertical) and width (transverse) directions once each, or twice each, such as longitudinal-transverse-longitudinal-transverse.

[0051] The biaxially oriented laminated polyester film of the present invention preferably has a total thickness of 10 μm or more and less than 50 μm. It is particularly preferably 12 μm or more and less than 40 μm. If the total thickness is less than 10 μm, handling during processing may become difficult due to insufficient strength. If the total thickness is 50 μm or more, it may be difficult to prevent deterioration in light transmittance and haze value, and economic efficiency may also be deteriorated.

[0052] The thickness of the layer B constituting the surface of the film is preferably 0.1 μm or more and less than 2 μm, more preferably 0.2 μm or more and less than 1.8 μm. If the thickness is less than 0.1 μm, the particles added to the polyester layer may be more likely to fall off. If the thickness is 2 μm or more, the average diameter and amount of the added particles must be further reduced to prevent the deterioration of the haze, which may make it difficult to achieve both good processing properties.

[0053] The biaxially oriented laminated polyester film of the present invention may contain particles within a range that can achieve the effects of the present invention. The particles may be organic or inorganic, and examples include silicon oxide, calcium carbonate, agglomerated aluminum oxide, aluminum silicate, mica, clay, talc, and barium sulfate. Organic particles include polyimide resins, olefin or modified olefin resins, cross-linked polystyrene resins, and silicone resins. When using these particles, to suppress increases in light transmittance and haze values, surface modification of the particles with a surfactant or the like to improve affinity with polyester is preferred in order to suppress the formation of voids around the added particles. Furthermore, particles with a shape close to spherical and a small difference in refractive index with the polyester are preferred, as they can suppress scattered light when ultraviolet rays pass through the film layer. Colloidal silica and organic particles are particularly preferred, and silicone particles and cross-linked polystyrene particles are also suitable. Among them, crosslinked polystyrene particles formed of a styrene-divinylbenzene copolymer prepared by emulsion polymerization are preferred because they have a particle shape close to spherical, a uniform particle size distribution, and can form uniform protrusions.

[0054] It is also possible to contain agglomerated alumina at the same time as the above-mentioned particles. Here, agglomerated alumina refers to a substance formed by the aggregation of several to several hundred particles with an average primary particle size of 5 nm or more and less than 30 nm. The average primary particle size of the agglomerated alumina is more preferably an average primary particle size of 8 nm or more and less than 15 nm. The agglomerated alumina can be a substance produced by flame hydrolysis or hydrolysis of alkoxide alumina using anhydrous aluminum chloride as a raw material. Agglomerated alumina is known to be of δ type, θ type, γ type, etc. as a crystalline type, and δ type alumina can be particularly suitable. These agglomerated aluminas are provided for use by adding them during polyester polymerization, for example, in the form of a slurry of ethylene glycol as a part of the raw material during polyester polymerization, crushing and dispersing them by a sand mill, etc., and fine filtration is performed, so that agglomerated alumina with an average secondary particle size of 0.01 μm or more and less than 0.2 μm can be obtained. When the agglomerated alumina obtained in this manner is added to a film, it is arranged in the plane direction by biaxial stretching, thus forming no substantial protrusions and having minimal impact on surface roughness. Furthermore, due to its excellent transmittance, increases in haze values ​​can be suppressed. The inclusion of agglomerated alumina provides a significant background enhancement effect on the film surface, improving wear resistance and suppressing the formation of concave defects caused by contact with stretching rollers. The agglomerated alumina is preferably included in the polyester resin composition constituting the surface layer (layer B), with its content preferably being 0.1% by mass or more and less than 5% by mass relative to the total polyester resin composition.

[0055] The size of the particles contained preferably does not include particles with a volume average particle size of 0.150 μm or more. When particles with a volume average particle size of 0.150 μm or more are contained, the incident angle of light during the exposure process may become uneven due to surface unevenness or particle aggregation, and light may be easily scattered, thereby causing unevenness on the wall surface of the resist pattern.

[0056] The particle size of the particles contained on the surface of the film is measured as follows. The polymer is removed from the film by a plasma low-temperature ashing method to expose the particles. The treatment conditions are selected so that the polymer is ashed but the particles are not damaged as much as possible. The treated sample is observed with a scanning electron microscope (SEM; S-4000 model manufactured by Hitachi, Ltd.), and the particle image is collected by an image analyzer (LUZEX_AP manufactured by Nireu Co., Ltd.), and the equivalent circle equivalent diameter is measured to find the volume average particle size of the particles. The magnification of the SEM is appropriately selected from 5000 to 20000 times according to the particle size. The observation position is arbitrarily changed, and the volume average particle size of at least 5000 particles is measured, and the average value is set as the volume average particle size of the particles. In addition, based on the results, the particle size represented by the level of 10 nm interval with 0 nm as the starting point is plotted on the horizontal axis, and the number of particles with this particle size is plotted on the vertical axis to make a particle size distribution graph to find the particle size with the maximum value.

[0057] In biaxially oriented laminated polyester films that provide high-resolution resist patterns, it is important to minimize the amount of lubricant contained in the film, which can cause resist pattern defects. However, reducing the amount of lubricant deteriorates the slip properties of the polyester film, leading to poorer winding properties of the polyester film itself and in the dry film resist manufacturing process, resulting in reduced yield. In the present invention, a lubricant resin layer is laminated on the film surface (A) opposite to the resist coating layer.

[0058] The base resin used for the lubricant resin layer is not particularly limited, and examples thereof include polyester-based, acrylic-based, and polyurethane-based resins. A mixture or copolymer thereof may also be used.

[0059] As the resin constituting the lubricant resin layer (X), water-dispersible polyester resins and water-dispersible acrylic resins are preferred from the viewpoints of coating properties and cost. In particular, acrylic copolymers are more preferred in terms of achieving both lubricity and transparency.

[0060] Examples of the water-dispersible acrylic resin include copolymers of monomers such as acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-methylolacrylamide, N-butoxyacrylamide, 2-hydroxyethyl methacrylate, and 2-hydroxyethyl acrylate.

[0061] Among these water-dispersible acrylic resins, the average emulsion particle size is preferably in the range of 50 nm to 200 nm, more preferably in the range of 70 nm to 150 nm. By using a water-dispersible acrylic resin having an average emulsion particle size in this range, the ten-point average surface roughness SRz(X) of the surface of the lubricant resin layer (X) can be achieved. The so-called emulsion particle size in the present invention refers to the major axis dimension of one colloid-dispersed particle dispersed in the emulsion. After the emulsion is dried, the colloid-dispersed particles of the acrylic resin scattered on the film surface are melted and agglomerated through a stretching and heat treatment process, thereby forming fine and flat protrusions on the film surface.

[0062] The midpoint glass transition temperature of the lubricant resin layer is preferably 40°C or higher, more preferably 60°C or higher. If the midpoint glass transition temperature is lower than 40°C, the surface viscoelasticity of the lubricant resin layer increases, resulting in poor slidability or blocking. While the upper limit of the midpoint glass transition temperature is not particularly limited, a resin with a midpoint glass transition temperature of 150°C or lower is generally preferred from the perspective of coating properties.

[0063] Furthermore, a cellulose-based polymer such as methyl cellulose or ethyl cellulose may be added in an amount of preferably 4 to 30 wt %, more preferably 10 to 20 wt % relative to the solid content of the acrylic resin, as long as the effects of the present invention are not impaired.

[0064] In order to improve the adhesion and mechanical strength of the easy-slip resin layer of the present invention, a crosslinking binder may be added as long as it does not impair the effects of the present invention. The crosslinking binder is not particularly limited as long as it is a crosslinking agent that undergoes a crosslinking reaction with functional groups present in the acrylic resin, such as hydroxyl groups, carboxyl groups, glycidyl groups, amide groups, etc. Representative substances include urea-based, melamine-based, acrylamide-based, polyamide-based resins, epoxy compounds, isocyanate compounds, aziridine compounds, Oxazoline compounds, etc. These crosslinking binders can be used alone or in combination depending on the situation. The amount of crosslinking binder added is appropriately selected depending on the type of crosslinker, but is generally preferably 0.01 to 50 parts by weight, more preferably 0.1 to 20 parts by weight, per 100 parts by weight of the resin solids. If the amount added is less than 0.01, the effect of crosslinking is low, while if it exceeds 50 parts by weight, the coating properties deteriorate, which is not preferred.

[0065] Furthermore, an antistatic agent may be added to the lubricant resin layer as long as the effects of the present invention are not impaired. The surface resistivity of the lubricant resin layer laminated on the film surface (A) is preferably 1.0×10 12Ω or less. By adding an antistatic agent, it is possible to prevent the adhesion of garbage and foreign matter caused by charging during the manufacture of the photoresist film. The antistatic agent is not particularly limited as long as it is a substance that shows compatibility with the resin constituting the resin layer. Examples of substances with excellent antistatic effects include compounds having a metal sulfonate group. Specifically, examples of substances having a sulfonic acid group include polystyrene sulfonate, lauryl diphenyl ether disulfonate, and stearyl diphenyl ether sulfonate. In addition, examples of antistatic agents that are not humidity-dependent and exhibit an antistatic effect even under low humidity conditions, such as in winter, include polythiophene and polyaniline.

[0066] The lubricant resin layer (X) of the biaxially oriented laminated polyester film of the present invention does not contain particles. If the lubricant resin layer contains particles, the particles aggregate, causing uneven light incidence during the exposure process. This can easily scatter light, resulting in unevenness on the resist pattern wall surface and a reduction in the yield when forming high-resolution resist patterns. Furthermore, if the lubricant resin layer contains particles, there is a risk that particles may fall off the lubricant resin layer during the film or dry film resist manufacturing process, contaminating the process.

[0067] The lubricant resin layer of the biaxially oriented laminated polyester film of the present invention preferably has an average thickness of 3 to 80 nm.

[0068] The intermediate layer (layer A) between the lubricant resin layer (X) and layer B of the biaxially oriented laminated polyester film of the present invention preferably contains substantially no particles. By not containing particles in layer A, the polyester film can have high transparency and can efficiently transmit ultraviolet rays.

[0069] In the case of the biaxially oriented laminated polyester film of the present invention comprising a lubricant resin layer (X) and a base layer composed of two layers, including a layer A having a film surface (A) and a layer B having a film surface (B), in layer A, when an area measuring 0.88 cm in the longitudinal direction and 1.16 cm in the width direction is observed 100 times using a laser microscope, the number of coarse particles with a long diameter of 15.0 μm or greater is preferably 5 or less, the number of coarse particles with a long diameter of 10.0 μm or greater and less than 15.0 μm is preferably 30 or less, and the number of coarse particles with a long diameter of 1.0 μm or greater and less than 10.0 μm is preferably 1500 or less. The presence of such coarse particles in layer A may cause scattering of ultraviolet light irradiated during the exposure process, resulting in omission of the resist pattern. Coarse particles in the present invention refer to solid substances that are incompatible with the polyester film and voids with such solid substances as central cores. Coarse particles are considered to be both single particles and aggregates of multiple particles. In the present invention, the term "longest diameter of coarse matter" refers to the longest length of coarse matter detected by the measurement method described below. The method for achieving the above-mentioned range of coarse matter is not particularly limited, and examples include controlling the mesh size of the foreign matter capture filter used during melt film formation. For example, when melt film formation is performed by coextrusion, it is effective to use a high-precision extruder that captures at least 95% of foreign matter larger than 2 μm.

[0070] In the case where the biaxially oriented laminated polyester film of the present invention comprises a lubricant resin layer (X) and a substrate layer composed of at least three layers including a layer A having a film surface (A), a layer B having a film surface (B), and a layer C having no film surface, it is preferred that, when an area measuring 0.88 cm in the longitudinal direction x 1.16 cm in the width direction is observed 100 times using a laser microscope, the number of coarse particles having a long diameter of 15.0 μm or more in layer C is 5 or less, the number of coarse particles having a long diameter of 10.0 μm or more and less than 15.0 μm is 30 or less, and the number of coarse particles having a long diameter of 1.0 μm or more and less than 10.0 μm is 1500 or less. If such coarse particles are present in layer A, ultraviolet rays irradiated during the exposure step may be scattered, resulting in omission of the resist pattern.

[0071] The biaxially oriented laminated polyester film of the present invention preferably has a film haze of 0.4% or less, more preferably 0.3% or less. If the film haze exceeds 0.4%, ultraviolet light scattering by the polyester film, which serves as the support for the resist layer, increases during ultraviolet exposure after laminating the polyester film with the resist layer. This may result in distortion or omission of the resist pattern after development, deterioration of the resist pattern wall surface, and deterioration of the polyester film's transmittance.

[0072] In the biaxially oriented laminated polyester film of the present invention, a dimensional change rate within the following range is preferred because it can suppress the generation of strain and wrinkles caused by heat shrinkage during the DFR processing step. The dimensional change rate can be achieved by appropriately adjusting the conditions such as relaxation and heat treatment under film production conditions using known methods. The dimensional change rate at 150°C is preferably 3.0% or less in the longitudinal direction and 2.0% or less in the width direction, more preferably 0.5% or more and 2.8% or less in the longitudinal direction, and 0.8% or more and 1.8% or less in the width direction. Furthermore, the dimensional change rate at 100°C is preferably 1.0% or less in both the longitudinal and width directions, and more preferably 0.1% or more and 0.8% or less. If the dimensional change rate is lowered from the lower limit of the above range, poor planarity may occur due to relaxation during the coating of the resist layer or during lamination. If it is higher than the upper limit, shrinkage stripes may be generated in a wavy shape due to shrinkage during the coating of the resist layer, resulting in poor planarity. In either case, the coating thickness of the resist layer may become uneven.

[0073] In addition, the biaxially oriented laminated polyester film of the biaxially oriented laminated polyester film roll for transfer materials of the present invention preferably has a strength of 70 MPa or more and less than 150 MPa when the film is stretched 5% in the longitudinal direction (hereinafter referred to as the F-5 value). If the F-5 value in the longitudinal direction is less than 70 MPa, damage may occur due to insufficient strength, thereby deteriorating the processing characteristics. On the other hand, if the F-5 value in the longitudinal direction is 150 MPa or more, it is sometimes difficult to achieve both the F-5 value in the width direction. The F-5 value in the longitudinal direction is preferably 80 MPa or more and less than 140 MPa, and more preferably 90 MPa or more and less than 130 MPa.

[0074] Furthermore, the F-5 value in the width direction is preferably 80 MPa or more and less than 160 MPa. If the F-5 value in the width direction is less than 80 MPa, insufficient strength may cause damage, resulting in poor processing characteristics. If it is 160 MPa or more, it may be difficult to achieve the same F-5 value in the longitudinal direction. It is preferably 90 MPa or more and less than 150 MPa, and more preferably 100 MPa or more and less than 140 MPa.

[0075] Furthermore, the breaking strength in the longitudinal direction is preferably 200 MPa or more and less than 360 MPa, more preferably 220 MPa or more and less than 340 MPa. The breaking strength in the width direction is preferably 260 MPa or more and less than 420 MPa, particularly preferably 280 MPa or more and less than 400 MPa. The above-mentioned F-5 value and breaking strength can be achieved by appropriately adjusting the stretching temperature and stretch ratio in the longitudinal and transverse directions.

[0076] Next, the method for producing the biaxially oriented laminated polyester film of the present invention will be described. As a method for incorporating inert particles into the polyester during melt film formation using a coextrusion method, for example, the inert particles are dispersed in ethylene glycol (the glycol component) at a predetermined ratio in the form of a slurry. After high-precision filtration capable of capturing at least 95% of coarse particles, such as those with a major diameter of 2 μm or greater or 5 μm or greater, the ethylene glycol slurry is added at any stage before the completion of polyester polymerization. When adding the particles, for example, adding the particles without drying the hydrosol or alcohol sol obtained during synthesis is preferred, as this improves particle dispersibility and suppresses the formation of coarse protrusions. Alternatively, a method in which the aqueous particle slurry is directly mixed with predetermined polyester pellets and then fed into a vented twin-screw kneading extruder to be incorporated into the polyester is also effective in achieving the effects of the present invention. As a method for adjusting the particle content, it is effective to preliminarily prepare a high-concentration particle masterbatch using the above method and then dilute the masterbatch with PET substantially free of particles during film formation to adjust the particle content. In this case, the density of the particle-containing voids can be controlled by pre-adjusting the intrinsic viscosity of the particle-free PET to be higher than the intrinsic viscosity of the particle-containing pellets. Furthermore, if the intrinsic viscosity of the particle-containing pellets is higher than the intrinsic viscosity of the particle-free PET, or if the intrinsic viscosity is the same, the density of the particle-containing voids tends to increase due to decreased dispersibility of the particles and shortened interparticle distances.

[0077] In this manner, the particle-containing masterbatch prepared for each layer is mixed with the substantially particle-free pellets in a predetermined ratio. After drying, the mixture is supplied to a known melt lamination extruder under a nitrogen stream or reduced pressure to prevent a decrease in intrinsic viscosity. The extruder used in the production of the biaxially oriented laminated polyester film of the present invention can be a single-screw or twin-screw extruder. Furthermore, to simplify the pellet drying process, a vented extruder equipped with a vacuum line can also be used. Furthermore, when providing an intermediate layer, since the extrusion volume is the highest, a so-called tandem extruder can be used, in which the functions of melting the pellets and maintaining the melted pellets at a constant temperature are shared between the extruders. Using a twin-screw vented extruder for extruding the surface layer of the biaxially oriented laminated polyester film of the present invention is preferred because it maintains good particle dispersion and suppresses particle aggregation.

[0078] The polymer melted and extruded by the extruder is filtered through a filter. Even if extremely small foreign matter enters the film, it will become a coarse protrusion defect, so it is effective to use a high-precision material for the filter, for example, to capture more than 95% of foreign matter with a long diameter of more than 2μm or more than 5μm. Then, it is extruded in a sheet form from a slit-shaped slit die, and cooled and solidified on a casting roller to produce an unstretched film. That is, multiple extruders, multi-layer flow channels or confluence blocks (for example, a confluence block with a rectangular confluence) are used for lamination, and the sheet is extruded from the die, and cooled with a casting roller to produce an unstretched film. In this case, from the viewpoint of stabilizing the back pressure and suppressing thickness fluctuations, it is effective to consider setting a static mixer or a gear pump in the polymer flow path.

[0079] The stretching method can be either simultaneous biaxial stretching or sequential biaxial stretching. In the case of sequential stretching, the stretching temperature in the longitudinal direction is preferably 95°C or higher and less than 120°C, more preferably 100°C or higher and less than 115°C. If the stretching temperature becomes less than 95°C, the film is prone to breakage, and if the stretching temperature becomes 120°C or higher, the film surface is susceptible to thermal damage, which is not preferred. In addition, from the viewpoint of preventing uneven stretching and damage, it is effective to set a preheating area before stretching and to heat in stages. The preheating temperature in the longitudinal direction is preferably 65°C to 130°C, more preferably 70°C to 110°C.

[0080] The stretching ratio in the longitudinal direction is preferably 3 times or more and less than 4.5 times, and more preferably 3.5 times or more and less than 4.3 times.

[0081] The resulting uniaxially stretched film is temporarily cooled. The cooling temperature is preferably 18°C ​​to 40°C, more preferably 21°C to 35°C. Cooling stabilizes the width dimensional stability, preventing damage and suppressing wrinkles on the film transport roll even on the smooth film surface of the present invention.

[0082] The film is then stretched in the width direction in a known tenter oven to form a biaxially stretched film. While held by a clamp running on a track within the tenter oven, the film is heated again in the oven to a temperature above the resin's midpoint glass transition temperature. The film is then stretched in the width direction as the track along which the clamps run expands. The widthwise stretch ratio is preferably 3.2x or greater and less than 5x, and more preferably 4.0x or greater and less than 4.6x.

[0083] Here, it is important to heat the film in stages to control the surface roughness and surface tilt of the film. By heating the uniaxially stretched film to 95°C to 120°C before stretching it in the width direction, and then stretching the film, which has been sufficiently heated to above the midpoint glass transition temperature of the resin, in the width direction at 105°C to 115°C, the film can be easily stretched and slight stretching unevenness caused by particles forming on the film surface can be suppressed.

[0084] Next, the obtained biaxially stretched film can be heat-treated. The heat treatment can be carried out in the same tenter oven after the widthwise stretching, or in a different oven from the tenter oven in which the widthwise stretching was carried out. The temperature of the heat treatment is preferably 190°C or higher and 250°C or lower. Heat treatment is preferred because it improves the dimensional stability of the film when exposed to high temperatures during subsequent processing steps or when used as a final product. In addition, it is also preferred to relax the film in the widthwise direction at a rate greater than 0% and less than 8% during the heat treatment to further improve the dimensional stability.

[0085] The biaxially stretched film is preferably cooled upon exiting the oven. The cooling temperature is preferably 60°C to 120°C, more preferably 70°C to 110°C. Cooling stabilizes the width dimension, preventing damage to the film transport roll and suppressing wrinkles even on the smooth film surface of the present invention.

[0086] The edges are then cut and wound to obtain an intermediate product. During this conveying process, the film thickness is measured and the data is fed back for use. The film thickness is adjusted by adjusting the die thickness, etc., and foreign matter is detected using a defect detector.

[0087] In the biaxially oriented laminated polyester film of the present invention, it is preferable to suppress the generation of cutting chips during edge cutting. A circular blade, shear blade, or straight blade can be used for edge cutting. Using a straight blade is preferred because it minimizes blade wear by preventing the blade from always contacting the film at the same position. Therefore, it is preferable to have a mechanism that vibrates the blade to an upper limit. Furthermore, it is preferable to install a suction device at the film cutting position to aspirate cutting chips and scraping powder generated by scraping the film ends after cutting.

[0088] The method for forming the lubricant resin layer (X) of the biaxially oriented laminated polyester film is not particularly limited, and examples thereof include coextrusion and coating. As a method for uniformly laminating the lubricant resin layer, the coating method is preferred. In addition, from the perspective of cost, an in-line coating method in which the lubricant resin layer is laminated before the transverse stretching step is also preferred.

[0089] The method for forming the lubricant resin layer is not particularly limited, and extrusion lamination and melt coating methods can be used. However, from the perspective of high-speed thin-film coating, known methods such as gravure coating, die coating, and metal rod coating using a water-dispersed coating agent are suitable. Prior to coating, the polyester film can be subjected to known surface treatments such as corona discharge treatment or plasma discharge treatment in air or other various atmospheres, as needed, to improve wettability and optimize coating properties.

[0090] The intermediate product is slit into appropriate widths and lengths in the slitting step and wound up to obtain a roll of the biaxially oriented laminated polyester film of the present invention. The film can be cut in the slitting step in the same manner as the aforementioned edge cutting.

[0091] The intermediate product is slit into desired widths to obtain the biaxially oriented laminated polyester film of the present invention. The biaxially oriented laminated polyester film of the present invention thus obtained has excellent transmittance and slip properties and is therefore suitable for use as a dry film resist support.

[0092] In particular, as the miniaturization of circuit wiring in electronic information equipment progresses, dry film resist support films used in the production of circuit wiring are required to minimize light scattering on the film surface during ultraviolet exposure to improve wiring traceability.

[0093] The biaxially oriented laminated polyester film of the present invention is preferably used in a manner of ultraviolet exposure from the lubricant resin layer (X) side because the lubricant resin layer (X) can suppress the influence of light scattering during ultraviolet exposure.

[0094] Example

[0095] The present invention will be further specifically described below with reference to Examples, but the present invention is not limited thereto and should not be interpreted.

[0096] (Measurement method)

[0097] (1) Measurement of the thickness of the laminated film and each layer

[0098] The total thickness of the laminated film was measured at 10 random points using a micrometer, and the average value was taken. Furthermore, ultrathin sections were cut from cross-sections of the laminated film and observed using a transmission electron microscope (TEM) at magnifications of 10,000 to 1,000,000 using RuO4 staining, OsO4 staining, or a combination of both. The thicknesses of the lubricant resin layer (X) and layers A and B of the polyester film were measured from these cross-sectional photographs.

[0099] (2) Film surface roughness (SRa, SRz values)

[0100] The surfaces of the lubricant resin layer (X) and (B) were measured using a three-dimensional microsurface profile analyzer (ET-350K, manufactured by Kosaka Seisakusho Co., Ltd.). The arithmetic mean surface roughness (SRa) and the ten-point average surface roughness (SRz) were determined from the resulting surface profiles in accordance with JIS B0601. The measurement conditions are as follows. The measurements were performed three times, and the average values ​​were designated as the SRa and SRz values, respectively.

[0101] X-direction measuring length: 0.5 mm, X-direction feed speed: 0.1 mm / s.

[0102] Y-direction feed pitch: 5μm, Y-direction line number: 40.

[0103] Cut-off: 0.25mm.

[0104] Stylus pressure: 0.02mN.

[0105] Height (Z direction) magnification: 50,000 times.

[0106] (3) Film haze

[0107] According to JIS K7105-1981, a sample having a length of 4.0 cm and a width of 3.5 cm was cut from the center of the film in the width direction and the haze was measured using a haze meter (Suga Test Instruments HGM-2DP (for light source C)). The measurement was performed three times, and the average value was used as the haze value.

[0108] (4) Friction coefficient

[0109] According to JIS K7125-1987, two samples were cut from a biaxially oriented laminated polyester film. After the surface of each sample was statically neutralized, the lubricant resin layer (X) of one sample was superposed on the surface (B) of the other sample. The film ends were fixed and a load of 200 g (normal force 1.96 N) was applied, causing the film to move 10 mm at a rate of 150 mm / min. The static and dynamic coefficients of friction were calculated from the tension at that time. This measurement was performed at 10 locations per 100 m in the longitudinal direction of the biaxially oriented laminated polyester film.

[0110] (5) Midpoint glass transition temperature of the lubricant resin layer

[0111] In differential scanning calorimetry (DSC) according to the provisions of "JIS K7121: 2012 Plastics transition temperature determination method (plastics transition temperature determination method)", a DSC Q100 manufactured by TA Instruments Inc. is used. The intersection of a straight line extending the baseline on the low temperature side toward the high temperature side during the second heating after heating and cooling and a tangent line drawn at the point where the gradient of the curve of the step-like change portion of the glass transition reaches a maximum is defined as the midpoint glass transition temperature.

[0112] (6) Number of large foreign objects

[0113] The biaxially oriented laminated polyester film was cut into 10 cm x 10 cm pieces, and an image was collected in layer A using a laser microscope (Keyence VK-X250). The collected image was binarized, and the number of coarse particles present within a certain depth range from the film surface was measured using a particle analysis module (Keyence VKH1XG). In layer A, an area of ​​0.88 cm in length and 1.16 cm in width was divided into sections of 220 μm in length and 290 μm in width. The images of each section were observed using a 50x objective lens. The above measurement operation was repeated 10 times to determine the number of coarse particles with a major diameter of 1.0 μm or more. In addition, the major diameter of the coarse particles in the present invention refers to the longest length of the coarse particles detected by the above measurement method.

[0114] (7) Particle size

[0115] The particle size of the particles contained on the surface of the film is measured as follows. The polymer is removed from the film by a plasma low-temperature ashing method to expose the particles. The treatment conditions are selected so that the polymer is ashed but the particles are not damaged as much as possible. The treated sample is observed with a scanning electron microscope (SEM; S-4000 model manufactured by Hitachi, Ltd.), and the particle image is collected by an image analyzer (LUZEX_AP manufactured by Nireu Co., Ltd.), and the equivalent circle equivalent diameter is measured to find the volume average particle size of the particles. The magnification of the SEM is appropriately selected from 5000 to 20000 times according to the particle size. The observation position is arbitrarily changed, and the volume average particle size of at least 5000 particles is measured, and the average value is set as the volume average particle size of the particles. In addition, based on the results, the particle size represented by the level of 10 nm interval with 0 nm as the starting point is plotted on the horizontal axis, and the number of particles with this particle size is plotted on the vertical axis to make a particle size distribution graph, and the particle size with the maximum value is found.

[0116] (8) Thermal shrinkage (dimensional change rate)

[0117] Two lines were drawn on the surface of the laminated film, each with a width of 10 mm and a measured length of approximately 100 mm. The distance between the two lines was measured at 23°C and designated as L0. The laminated film sample was placed in an Espeshk Co., Ltd. hot air oven "HIGH-TEMP-OVEN PHH-200" set at 150°C (air flow meter "7") under a load of 3 g for 30 minutes. The distance between the two lines was then measured again at 23°C and designated as L1. The thermal shrinkage ratio was calculated using the following formula. Five samples were measured in both the longitudinal and transverse directions, and the average value was used for evaluation.

[0118] Thermal shrinkage (%) = (L0-L1) / L0×100

[0119] It should be noted that when analyzing a film, if the length direction and width direction of the film are unknown, the direction with the maximum refractive index in the film is regarded as the width direction, and the direction perpendicular thereto is regarded as the length direction. The direction of the maximum refractive index in the film can be determined by measuring the refractive index in all directions of the film using an Abbe refractometer, for example, by determining the slow axis direction using a phase difference measuring device (birefringence measuring device) or the like.

[0120] (9) Scratch resistance

[0121] A film measuring 10 mm wide and 200 mm long was wrapped with the lubricant resin layer side around a hard chrome-plated needle with a diameter of 2 mm at a wrapping angle of 30°. The film and needle were rubbed against each other three times with a load of 50 g. This test was repeated five times, and the film's appearance was evaluated as follows.

[0122] S: The membrane is almost not damaged

[0123] A: The membrane is slightly damaged

[0124] B: The membrane is damaged, and scraping and shedding are observed on the needle.

[0125] (10) Visual inspection of resist resolution

[0126] The visual evaluation method for the resolution of the resist in the biaxially oriented laminated polyester film of the present invention is carried out by the following procedure.

[0127] (i) A negative resist "PMER N-HC600" manufactured by Tokyo Ohka Co., Ltd. was applied to a single-side mirror-polished 6-inch Si wafer and spun using a large spinner to form a 7 μm thick resist layer. This layer was then pre-heated at 70°C for approximately 20 minutes in a nitrogen-circulating ventilation oven.

[0128] (ii) The B-layer side surface of the polyester film is overlapped in a manner that it contacts the resist layer, and the polyester film is laminated on the resist layer using a rubber roller. A photomask patterned with chromium metal is arranged thereon, and exposure is performed from the photomask using an I-ray stepper exposure machine.

[0129] (iii) After the polyester film was peeled off from the resist layer, the resist layer was placed in a container containing developer N-A5 and developed for about 1 minute. Thereafter, the resist layer was removed from the developer and washed with water for about 1 minute.

[0130] (iv) The L / S (μm) (Line and Space) state of the resist pattern produced after development was observed using a scanning electron microscope (SEM) at 1500 magnification. The resolution of the resist was evaluated according to the following criteria. It should be noted that an evaluation of B or above is considered a practical level.

[0131] S: L / S = 5 / 5 μm was clearly confirmed.

[0132] A: L / S=5 / 5 μm could not be clearly confirmed, but L / S=8 / 8 μm could be clearly confirmed.

[0133] B: L / S=8 / 8 μm could not be clearly confirmed, but L / S=10 / 10 μm could be clearly confirmed.

[0134] C: L / S = 10 / 10 μm. Unable to confirm clearly (not applicable to production).

[0135] (11) Handleability of resist film (slip evaluation)

[0136] A resist film was produced by coating a negative-type photosensitive resin on the surface of the layer B side using the biaxially oriented laminated polyester film of the present invention as a support. The following criteria were used to evaluate the slip properties, which serve as a measure of workability during resist film production. A rating of A or higher indicates a practically acceptable level.

[0137] S: Appropriate sliding properties and good operability.

[0138] A: Poor sliding properties and poor operability.

[0139] B: Due to lack of appropriate sliding properties, handling is difficult (not applicable to production).

[0140] (12) Surface resistivity

[0141] An insulating plastic plate was placed on a stainless steel plate attached to a surface resistivity meter (Model 152-1) manufactured by Torek Japan Co., Ltd. The sample was set so that the film surface (B) of the biaxially oriented laminated polyester film of the present invention was in contact with the insulating plate. The lubricant resin layer (X), serving as the measurement surface, was brought into contact with the probe electrode, a voltage of 100 V was applied, and the value after 1 minute was recorded.

[0142] (13) Conductor circuit wiring defect evaluation

[0143] The wiring defect evaluation method that contributes to the yield of the conductor circuit when the biaxially oriented laminated polyester film of the present invention is used as a support for a dry film resist is carried out by the following procedure.

[0144] (i) A negative resist "PMER N-HC600" manufactured by Tokyo Ohka Co., Ltd. was applied to a 6-inch Si wafer with one side mirror-polished. The resist layer was then spun using a large spinner to form a 7-μm thick resist layer. This layer was then pre-heated at 70°C for approximately 20 minutes in a nitrogen-circulating ventilation oven.

[0145] (ii) The polyester film was placed so that the layer B side of the polyester film was in contact with the resist layer, and the polyester film was laminated onto the resist layer using a rubber roller. The prepared dry film resist was attached so that the resist layer side of the resist layer was in contact with the copper-clad laminate. A photomask patterned with chromium metal was placed on the layer A side, and exposure was performed through this photomask using an I-ray stepper.

[0146] (iii) After the polyester film was peeled off from the resist layer, the resist layer was placed in a container containing developer N-A5 and developed for about 1 minute. Thereafter, the resist layer was removed from the developer and washed with water for about 1 minute.

[0147] (iv) The copper-clad laminate with the remaining resist layer after development was immersed in a ferric chloride solution to etch the exposed copper. The resist layer was then peeled off to form a conductor circuit with L / S = 10 / 10 μm.

[0148] The state of the produced conductor circuit was measured using an optical microscope (LV-100 manufactured by NICON). 2 The area was observed at 500 times the magnification, and the wiring defect of the conductor circuit was evaluated according to the following criteria. It should be noted that an evaluation of A or higher is a practical level.

[0149] S: The maximum major diameter of the wiring defect is less than 2.4μm

[0150] A: The maximum major diameter of the wiring defect is less than 3.2μm

[0151] B: The maximum major diameter of the wiring defect is less than 4.0μm

[0152] (14) Intrinsic viscosity (IV)

[0153] The value calculated from the solution viscosity measured in o-chlorophenol at 25°C using the following formula was used.

[0154] ηsp / C=[η]+K[η]2·C

[0155] Here, ηsp = (solution viscosity / solvent viscosity) - 1, C is the weight of the dissolved polymer per 100 m of solvent (g / 100 ml, usually 1.2), and K is the Huggins constant (0.343). The solution viscosity and solvent viscosity were measured using an Ostwald viscometer.

[0156] In addition, when measuring the intrinsic viscosity (IV) of the polyester resin constituting the outermost polyester layer of the polyester film, the polyester resin constituting the outermost polyester layer of the polyester film is cut out and measured.

[0157] In addition, when measuring the intrinsic viscosity of the polyester resin constituting the polyester layer other than the outermost layer of the polyester film, after calculating the ratio of the layer thickness of each layer of the polyester film by the method (1), the intrinsic viscosity of the entire polyester film is measured in the same manner as above, and the intrinsic viscosity of the polyester resin constituting the polyester layer other than the outermost layer is calculated based on the weight ratio.

[0158] When the solution containing the measurement sample contains insoluble matter such as inorganic particles, correction is performed by filtering the solution and measuring the weight, and subtracting the weight of the filtrate from the measurement sample weight as the measurement sample weight.

[0159] (raw material)

[0160] (Production of Polyester A)

[0161] 86.5 parts by weight of terephthalic acid and 37.1 parts by weight of ethylene glycol were subjected to an esterification reaction at 255°C while distilling off water. After the esterification reaction was completed, 0.02 parts by weight of trimethylphosphoric acid, 0.06 parts by weight of magnesium acetate, 0.01 parts by weight of lithium acetate, and 0.0085 parts by weight of antimony trioxide were added. Subsequently, the mixture was heated to 290°C under vacuum, and the temperature was raised to allow for a polycondensation reaction, yielding polyester pellets with an intrinsic viscosity of 0.63 dl / g (Polyester A).

[0162] (Production of Polyester B)

[0163] When polyester was produced in the same manner as for the production of polyester A described above, spherical silica having a volume average particle size of 0.06 μm, a volume shape factor f=0.51, and a Mohs hardness of 7 was added after transesterification and subjected to a polycondensation reaction to obtain a silica-containing masterbatch (Polyester B) containing 1.0% by weight of particles relative to the polyester. The spherical silica used was prepared by stirring a mixed solution of ethanol and ethyl silicate while adding a mixed solution of ethanol, pure water, and aqueous ammonia as an alkaline catalyst to the mixed solution. The resulting reaction solution was stirred to allow hydrolysis of the ethyl silicate and polycondensation of the hydrolysis product, followed by post-reaction stirring to obtain monodisperse silica particles.

[0164] (Production of Polyester C)

[0165] When polyester was produced in the same manner as for the production of polyester A, spherical silica having a volume average particle size of 0.2 μm, a volume shape factor f=0.51, and a Mohs hardness of 7 was added after transesterification, and a polycondensation reaction was carried out to obtain a silica-containing masterbatch (Polyester C) containing 2% by weight of particles relative to the polyester. The spherical silica used was prepared by stirring a mixed solution of ethanol and ethyl silicate, while adding a mixed solution of ethanol, pure water, and aqueous ammonia as an alkaline catalyst to the mixed solution. The resulting reaction solution was stirred to carry out a hydrolysis reaction of the ethyl silicate and a polycondensation reaction of the hydrolysis product, followed by post-reaction stirring to obtain monodisperse silica particles.

[0166] (Production of Polyester D)

[0167] A 10% ethylene glycol slurry of delta-alumina, agglomerated alumina, was pulverized and dispersed using a sand mill, and then filtered through a 3 μm filter with a 95% capture efficiency. This slurry was then added to the transesterification product prepared in the same manner as in the preparation of Polyester A. Antimony trioxide was then added to allow polycondensation to proceed, yielding a masterbatch containing 1.5% by weight of agglomerated alumina and having an intrinsic viscosity of 0.62 dl / g (Polyester D).

[0168] (Example 1)

[0169] The raw materials for each layer, prepared as shown in Table 1, were stirred in a blender. The raw materials for Layer B were fed into a vented twin-screw extruder for Layer B. The raw materials for Layer A were dried under reduced pressure at 120-140°C for at least one hour and then fed into a single-screw extruder for Layer A. Subsequently, the materials were melt-extruded at 275°C. Layer A was filtered using a high-precision filter that captured at least 95% of particles larger than 5μm, and Layer B was filtered using a high-precision filter that captured at least 95% of particles larger than 2μm. The materials were then joined and laminated using a rectangular two-layer junction block to produce a two-layer laminate consisting of Layers A and B. The film was then wound onto a casting drum with a surface temperature of 23°C using an electrostatic casting method over a cooling roll through a slot die maintained at 285°C, and cooled to solidify, yielding an unstretched laminate film.

[0170] After preheating the unstretched film with a heated roller at 68-99°C, it was stretched to 4 times in the longitudinal direction at 113-115°C using a stretching roller with a surface roughness Ra of 0.2 μm. The uniaxially stretched film was then cooled by 88-90°C lower than the stretching temperature. A 0.4% solids solution of a water-dispersible acrylic copolymer (midpoint glass transition temperature 80°C, emulsion particle size 90-120 nm) was then applied to the surface of layer A of the uniaxially stretched film using a metal bar coating method. Furthermore, the film was stretched to 4.3 times in the width direction using a tenter frame under hot air at 103-112°C. The film was then heat-treated at 222°C for 3 seconds under a constant tension, and then relaxed by 0.1% in the longitudinal direction and 3.3% in the width direction. This yielded an intermediate product of a biaxially oriented laminated polyester film with a total thickness of 16 μm, including a 10 nm layer of lubricant resin. The intermediate product was slit by a slitter to obtain a roll of a biaxially oriented laminated polyester film having a thickness of 16 μm. The evaluation results of the obtained film are shown in Table 2. As described above, the biaxially oriented laminated polyester film of the present invention was excellent in friction coefficient and resist resolution.

[0171] (Examples 2 and 3)

[0172] A biaxially oriented laminated polyester film was obtained in the same manner as in Example 1, except that the composition of layer B was changed as shown in Table 1. The evaluation results of the obtained film are shown in Table 2. Thus, the biaxially oriented laminated polyester film of the present invention exhibited excellent slidability and resist resolution, similar to Example 1.

[0173] (Example 4)

[0174] After stirring the raw materials for each layer as shown in Table 1 in a blender, the raw materials for layers A and B were fed into vented twin-screw extruders for layers A and B. The raw material for layer C was dried under reduced pressure at 120-140°C for at least one hour and then fed into a single-screw extruder for layer C. Subsequently, the materials were melt-extruded at 275°C. Layers A and C were filtered using a high-precision filter that captured at least 95% of particles larger than 5μm, and layer B was filtered using a high-precision filter that captured at least 95% of particles larger than 2μm. The materials were then joined and laminated using a rectangular three-layer junction block to produce a three-layer laminate consisting of layers A, C, and B. The film was then passed through a slot die maintained at 285°C, electrostatically cast onto a cooling roll, and wound onto a casting drum with a surface temperature of 23°C. The film was cooled and solidified to produce an unstretched laminated film.

[0175] After preheating the unstretched film with a heated roller at 68-99°C, it was stretched to 4 times in the longitudinal direction at 113-115°C using a stretching roller with a surface roughness Ra of 0.2 μm. The uniaxially stretched film was then cooled by 88-90°C lower than the stretching temperature. A 0.4% solids solution of a water-dispersible acrylic copolymer (midpoint glass transition temperature 80°C, emulsion particle size 90-120 nm) was then applied to the surface of layer C of the uniaxially stretched film using a metal bar coating method. Furthermore, the film was stretched to 4.3 times in the width direction using a tenter frame under hot air at 103-112°C. The film was then heat-treated at 222°C for 3 seconds under a constant tension and then relaxed by 0.1% in the longitudinal direction and 3.3% in the width direction. This yielded an intermediate product of a biaxially oriented laminated polyester film with a total thickness of 16 μm, including a 10 nm layer of a lubricant resin layer. The intermediate product was slit by a slitter to obtain a roll of a biaxially oriented laminated polyester film having a thickness of 16 μm. The evaluation results of the obtained film are shown in Table 2. As described above, the biaxially oriented laminated polyester film of the present invention was excellent in friction coefficient and resist resolution.

[0176] (Examples 5 and 6)

[0177] A biaxially oriented laminated polyester film was obtained in the same manner as in Example 4 except that the composition of layer B was changed as shown in Table 1. The evaluation results of the obtained film are shown in Table 2. Thus, the biaxially oriented laminated polyester film of the present invention was excellent in slip properties and resist resolution, as in Example 4.

[0178] (Comparative Example 1)

[0179] After stirring the raw materials for each layer as shown in Table 1 in a blender, the raw materials for layers B and C were fed into vented twin-screw extruders for layers B and C. The raw material for layer A was dried under reduced pressure at 120-140°C for at least one hour and then fed into a single-screw extruder for layer A. Subsequently, the materials were melt-extruded at 275°C. Layers A and C were filtered using a high-precision filter that captured at least 95% of particles larger than 5μm, and layer B was filtered using a high-precision filter that captured at least 95% of particles larger than 2μm. The materials were then joined and laminated using a rectangular three-layer junction block to produce a three-layer laminate consisting of layers A, B, and C, with layers C and B having surfaces. The film was then wound onto a casting drum with a surface temperature of 23°C using an electrostatic casting method on a cooling roll through a slot die maintained at 285°C. The film was then cooled and solidified to produce an unstretched laminated film.

[0180] After preheating the unstretched film with a heated roller at 68-99°C, it was stretched to 4 times in the longitudinal direction at 113-115°C using a stretching roller with a surface roughness Ra of 0.2 μm. The uniaxially stretched film was then cooled by 88-90°C lower than the stretching temperature. Furthermore, the film was stretched to 4.3 times in the width direction using a tenter frame with hot air at 103-112°C. It was then heat-treated at 222°C for 3 seconds under a constant tension and then relaxed by 0.1% in the longitudinal direction and 3.3% in the width direction to obtain an intermediate product of a biaxially oriented laminated polyester film with a total thickness of 16 μm. This intermediate product was slit using a slitter to obtain rolls of biaxially oriented laminated polyester film with a thickness of 16 μm. The evaluation results of the resulting films are shown in Table 2.

[0181] (Comparative Example 2)

[0182] A biaxially oriented laminated polyester film was obtained in the same manner as in Example 1, except that the solution of the lubricant resin layer components was changed to a 0.5% solution containing a water-dispersible acrylic copolymer (midpoint glass transition temperature 80°C, emulsion particle size 90-120 nm) and colloidal silica particles with a volume average particle size of 30 nm at a solids concentration of 9:1, and the average thickness of the lubricant resin layer was changed to 30 nm. The evaluation results of the resulting film are shown in Table 2.

[0183] (Comparative Example 3)

[0184] A biaxially oriented laminated polyester film was obtained in the same manner as in Example 1 except that the composition of the B layer was changed as shown in Table 1 and the average thickness of the lubricant resin layer was changed to 100 nm.

[0185] [Table 1]

[0186]

[0187] [Table 2-1]

[0188]

[0189] [Table 2-2]

[0190]

[0191] Industrial availability

[0192] The biaxially oriented laminated polyester film of the present invention has excellent resist coating properties and slip properties and can be used for a dry film resist support capable of obtaining a high-resolution resist pattern with good reproduction and high yield.

Claims

1. A biaxially oriented laminated polyester film for use as a dry film resist support, characterized in that: Satisfy the following (1) to (4), (1) A laminated polyester film comprising a lubricant resin layer X and a substrate layer, wherein the substrate layer is composed of at least two layers including a layer A and a layer B, wherein the layer A has a film surface A and the layer B has a film surface B, (2) Laminating a lubricating resin layer X containing no particles on the film surface A side, (3) The arithmetic mean roughness SRa(B) of the film surface B on the opposite side to the film surface A is less than 7 nm, (4) The static friction coefficient between the lubricant resin layer X and the film surface B measured at 10 locations every 100 m in the longitudinal direction was 0.4 to 0.8, and the dynamic friction coefficient was 0.3 to 0.

7.

2. The biaxially oriented laminated polyester film according to claim 1, wherein the ten-point average surface roughness SRz(X) of the lubricant resin layer X and the ten-point average surface roughness SRz(B) of the film surface B are both 10 nm or more and 70 nm or less. 3 . The biaxially oriented laminated polyester film according to claim 1 , wherein the lubricant resin laminated on the film surface A has a midpoint glass transition temperature of 40° C. or higher. The biaxially oriented laminated polyester film according to claim 1 , which does not contain particles having a volume average particle size of 0.150 μm or more.

5. The biaxially oriented laminated polyester film according to claim 1, wherein in the A layer, when an area of ​​0.88 cm in the length direction × 1.16 cm in the width direction is observed 10 times by a laser microscope, the number of coarse particles with a long diameter of 15.0 μm or more is 5 or less, the number of coarse particles with a long diameter of 10.0 μm or more and less than 15.0 μm is 30 or less, and the number of coarse particles with a long diameter of 1.0 μm or more and less than 10.0 μm is 1500 or less.

6. The biaxially oriented laminated polyester film according to claim 1, wherein in the C layer having no film surface and disposed between the A layer and the B layer, when an area of ​​0.88 cm in the length direction and 1.16 cm in the width direction is observed 10 times by a laser microscope, the number of coarse particles having a long diameter of 15.0 μm or more is 5 or less, the number of coarse particles having a long diameter of 10.0 μm or more and less than 15.0 μm is 30 or less, and the number of coarse particles having a long diameter of 1.0 μm or more and less than 10.0 μm is 1500 or less.

7. The biaxially oriented laminated polyester film according to claim 1, wherein the surface resistivity of the lubricant resin laminated on the film surface A is 1.0×10 12 Ω or less.

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