Film for dry film resist support

Abstract

It has excellent slipperiness, is easy to peel off from the resist, suppresses the transfer of irregularities to the resist surface after peeling, and allows for obtaining high-resolution resist patterns with a high yield. [Solution] The polyester film has a particle-free, smooth layer (X) on one side and a non-silicone coating layer (Y) on the opposite side, with 200 coarse protrusions of 50 nm or more per mm on the surface of the non-silicone coating layer. 2 A film for a dry film resist support, characterized by the following features.

Description

[Technical Field]

[0001] This invention relates to a film for a dry film resist support. [Background technology]

[0002] Biaxially oriented laminated polyester films are widely used as transfer materials such as dry film resists for printed circuit board circuit formation.

[0003] Dry film resists are used to form circuits in printed circuit boards, semiconductor packages, flexible substrates, and other applications. Dry film resists have a structure in which a photosensitive layer (photoresist layer) is coated onto a polyester film as a support, and then sandwiched between protective films (cover films) made of polyethylene film, polypropylene film, polyester film, etc.

[0004] Conventional positive-type photosensitive resists widely used include quinone diazide-based materials and materials primarily composed of novolac resin. When these positive-type photosensitive resists are coated onto a support such as polyethylene terephthalate film to create a positive-type dry film resist, the adhesion between the support film and the positive-type photosensitive resist layer is high. This leads to a problem where the support film cannot be peeled off after thermal bonding to a substrate using a lamination method.

[0005] Furthermore, novolac resin is hard, has a brittle film quality, and lacks flexibility, which posed a problem when it was heat-pressed onto a substrate using the lamination method, as it did not adhere well to the substrate. While lamination is possible by supplying sufficient heat and pressure through measures such as increasing the temperature of the laminator's heat rolls and slowing the transport speed, applying temperatures above 130°C causes the support to soften and expand or contract, resulting in a problem. In addition, the positive-type photosensitive resist layer does not soften sufficiently, leading to the formation of air bubbles between the substrate and the positive-type photosensitive resist layer.

[0006] Furthermore, plasticizers are sometimes added to the positive photosensitive resist layer to enable heat bonding by lamination, or the softening point of the novolac resin is lowered to lower the softening point of the positive photosensitive resist layer. However, when a coating solution for the positive photosensitive resist layer is applied to a support film, dried, wound up, and stored in a roll, a problem called "blocking" occurs during long-term storage at room temperature, where the positive photosensitive resist layer sticks to the support film on the opposite side.

[0007] One way to prevent blocking is to harden the positive-type photosensitive resist layer. However, since the positive-type photosensitive resist layer inherently lacks flexibility, the aforementioned problems become more likely to occur. Furthermore, because the positive-type photosensitive resist layer lacks flexibility and is brittle, cracks may occur if the positive-type dry film resist is bent. In addition, there are difficulties in forming positive-type dry film resist into rolls. Specifically, when slitting a wide roll into a roll product of the desired width, cracks tend to occur in the brittle positive-type photosensitive resist layer, and chips are easily generated from the edges.

[0008] Furthermore, while roll-type positive dry film resist is typically heat-pressed onto single-sheet substrates, it is necessary to cut the positive dry film resist between each substrate. This process often causes the positive photosensitive resist layer to crack, generating chips and debris. These chips can then adhere to the substrate, resulting in defects.

[0009] To address these problems, one solution is to provide a release layer between the support film and the positive-type photosensitive resist layer (for example, Patent Documents 1 and 2).

[0010] Specifically, Patent Document 1 discloses a multilayer dry film photoresist comprising, in order, a peelable support layer (support film) having a release layer, a first photoresist layer, and a second layer of a translucent or crosslinkable organic polymer. Patent Document 2 discloses a resist film including a support film (support film), a dry film resist film for reinforcing the mechanical strength of the resist film, and a resist film used for pattern formation. The release layer facilitates the peeling of the support film after thermal bonding. However, it is necessary to increase the adhesion between the release layer and the positive photosensitive resist layer to prevent cracking of the positive photosensitive resist layer when the positive dry film resist is bent. Furthermore, the stronger the adhesion between the release layer and the positive photosensitive resist layer, the more likely it is that only the support film will peel off during peeling after thermal bonding, while the release layer will remain on the positive photosensitive resist layer, which can cause defects in the image after development during exposure. In Patent Document 3, the support film of the photoresist layer has a second layer that can be attached to it, thereby suppressing peeling and delamination of the photoresist layer. However, in order to form a fine pattern, it is preferable that there is no second layer.

[0011] Regarding Patent Documents 1 and 2, there is a problem in that protrusions on the surface of the release coating are transferred to the resist surface, leading to circuit defects and problems during subsequent processing.

[0012] The polyester film used as the support requires transparency that allows ultraviolet light to pass through, smoothness that allows for the application of resists, and slipperiness during the manufacturing of dry film resists.

[0013] It is known that poor slipperiness can cause wrinkles and granular defects when winding polyester film into a roll, leading to reduced yield due to the inability to uniformly apply the resist. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] Japanese Patent Publication No. 59-083153 [Patent Document 2] Patent No. 3514415 [Overview of the Initiative] [Problems that the invention aims to solve]

[0015] In view of these circumstances, the object of the present invention is to address the problems of polyester films used as supports for positive-type photosensitive resists as described above, and to provide a film for dry film resist supports that has excellent resist coating properties and slipperiness over a large area, is easy to peel from positive-type photosensitive resists, and suppresses the transfer of irregularities to the resist surface after peeling, thereby enabling the acquisition of high-resolution resist patterns with a high yield. [Means for solving the problem]

[0016] The present invention has the following features. [1] A polyester film having a particle-free, smooth layer (X) on one side and a non-silicone coating layer (Y) on the opposite side, with the non-silicone coating layer having 200 coarse protrusions of 50 nm or more per mm² on its surface. 2 The following is a film for dry film resist support. [2] When an area measuring 7.5 mm in the longitudinal direction and 1.1 mm in the width direction was observed using a white light source of an optical microscope, the number of coarse foreign objects with a major axis of 1 μm or larger was 20 per cm. 2 The following is observed: the number of gel particles with a major axis of 1 μm or larger when observed using a polarized light source is 2 particles / cm². 2 The following is a film for a dry film resist support as described in [1]. [3] The film for dry film resist support according to [1], characterized in that the thickness of the polyester film is 188 μm or less and 10 μm or more. [4] The polyester film is a laminated polyester film of at least two layers, containing particles with a particle size of 0.1 μm or less on the non-silicon-coated surface at 0.5% by mass or more and 2% by mass or less based on the film, and the thickness of the layer containing the particles is 0.05 to 2.0 μm. The film for a dry film resist support according to [1]. [5] The film for a dry film resist support according to [1], characterized in that it is exposed after peeling. [6] The film for a dry film resist support according to [1], characterized in that the moving average of the thickness unevenness when measuring the thickness unevenness of 2000 m in the longitudinal direction of the film is 6.0% or less.

Effect of the Invention

[0017] According to the film for a dry film resist support of the present invention, when used in a dry film resist, it has excellent resist coating properties and sliding properties over a wide area, is easy to peel from a positive photosensitive resist, suppresses the transfer of unevenness to the resist surface after peeling, and can obtain a high-resolution resist pattern with a high yield.

Mode for Carrying Out the Invention

[0018] Hereinafter, the present invention will be described in detail together with preferred embodiments. One surface of the film for a dry film resist support of the present invention (hereinafter, also simply referred to as a film) (the outer surface is defined as surface (A)) is a particle-free and easy-sliding coating layer, and a non-silicon coating layer is required on the other surface (this surface is defined as surface (B)). Further, the number of coarse protrusions of 50 nm or more on the surface of the non-silicon coating layer is 200 per mm 2 or less, and more preferably, the number of coarse protrusions is 100 per mm 2 or less. By having the surface layer and setting the number of coarse protrusions on surface (B) within the above range, it is possible to suppress the chipping of the resist due to the transfer of coarse protrusions, and particularly to suppress the chipping of the resist surface when exposed after peeling, and it becomes possible to form a photoresist layer without defects on the surface. When the number of coarse protrusions is 200 per mm 2When it exceeds a certain level, it may cause coating omission or transfer failure when used as a dry film resist, which is unsuitable. The number of coarse protrusions is 200 per mm 2 To achieve the following, it is preferable to adjust the particle diameter and content of the particles contained in the polyester film itself, and not to contain foreign substances that cause protrusions in the non-silicon coating layer on the surface itself and during coating.

[0019] When observing the film of the present invention in a region of 7.5 mm in the longitudinal direction × 1.1 mm in the width direction using the white light source of an optical microscope, the number of coarse foreign substances having a major axis of 1 μm or more present is 20 per cm 2 It is preferably below, and more preferably 15 per cm 2 Below. Also, the number of gelled products having a major axis of 1 μm or more present when observed using a polarized light source is 2 per cm 2 It is preferably below, and more preferably 1 or less. By setting the number of coarse foreign substances and gelled products below the above levels, exposure inhibition can be suppressed, circuit defects can be prevented, and the circuit yield can be maintained.

[0020] In the present invention, the polyester film used preferably has a base layer having a laminated structure of two or more layers, from the viewpoint of increasing the slipperiness of the film and improving its transparency. When the polyester film used in the present invention has a two-layer laminated structure, a two-layer laminated structure of two types, an a-layer and a b-layer, is preferred. A two-layer laminated structure of two types, an a-layer and a b-layer, is preferred because it makes it easy to impart suitable properties to the surface (A) of the particle-free slippery layer (X) (and the film surface (a) of layer a) and the film surface (B) of layer (Y). When there is a three-layer laminated structure, a three-layer laminated structure of three types, an a-layer, a c-layer, and a b-layer, or other laminated configurations are also acceptable. A three-layer laminated structure of three types, an A-layer, a c-layer, and a b-layer, makes it possible to impart suitable properties to the surface of the particle-free slippery layer (X) (and the film surface (A) of layer A) and the surface of the non-silicone coating layer (Y) (and the film surface (b) of layer b). When a resist layer is laminated on the film surface (b) side, it is preferable to use it so that it is exposed to ultraviolet light from the surface side of the slippery resin layer (X). Furthermore, when the cover film is laminated to the resist layer and wound up, it is preferable that the surface of the slippery resin layer (X) (surface (A)) is the surface that comes into contact with the cover film. Note that the film surface refers to the surface including the longitudinal direction and the width direction of the film.

[0021] The polyester resin constituting the film of the present invention is preferably a polyester obtained by polymerization from monomers or low polymers mainly composed of dicarboxylic acids, diols, and their ester-forming derivatives, with at least 70 mol% being the main constituent components. In the present invention, it is preferable to use an aromatic dicarboxylic acid as the dicarboxylic acid.

[0022] Examples of aromatic dicarboxylic acids include terephthalic acid and 2,6-naphthalenedicarboxylic acid, with terephthalic acid being particularly preferred. These acid components may be used individually or in combination of two or more, and other aromatic dicarboxylic acids such as isophthalic acid, or fatty acids, may be partially copolymerized.

[0023] Examples of diol components include ethylene glycol, 1,2-propanediol, 1,3-propanediol, and neopentyl glycol. Ethylene glycol is preferred among these. These diol components may be used individually or in combination of two or more.

[0024] Preferably, the polyester used in the film of the present invention includes polyethylene terephthalate, polyethylene naphthalate and its copolymers, polybutylene terephthalate and its copolymers, polybutylene naphthalate and its copolymers, and further, polyhexamethylene terephthalate and its copolymers, polyhexamethylene naphthalate and its copolymers, and others. From the viewpoint of performance and economy, polyethylene terephthalate is particularly preferred.

[0025] The polyester used in the film of the present invention can be produced by conventionally known methods. For example, it can be produced by directly esterifying an acid component with a diol component, then heating the product under reduced pressure to remove excess diol component while polycondensing, or by using a dialkyl ester as the acid component, transesterifying it with the diol component, and then polycondensing it in the same manner as above. In this case, conventionally known alkali metals, alkaline earth metals, manganese, cobalt, zinc, antimony, germanium, titanium compounds, etc., can be used as reaction catalysts as needed.

[0026] The intrinsic viscosity of the polyester used in the film of the present invention is preferably 0.50 dl / g or more and less than 0.80 dl / g. More preferably, it is 0.55 dl / g or more and less than 0.70 dl / g.

[0027] The film of the present invention is preferably biaxially oriented. In the present invention, biaxial orientation refers to a state in which an unstretched (unoriented) film is stretched in two dimensions by a conventional method (showing a biaxial orientation pattern in wide-angle X-ray diffraction). Stretching can be performed using sequential biaxial stretching or simultaneous biaxial stretching. Sequential biaxial stretching can involve stretching in the longitudinal (vertical) and widthwise (horizontal) directions, either once in the longitudinal and once in the horizontal direction, or twice in each direction, such as longitudinal-horizontal-longitudinal-horizontal.

[0028] The film of the present invention preferably has a total thickness of 10 μm or more and less than 188 μm. Particularly preferably it is 12 μm or more and less than 150 μm. If the total thickness is less than 10 μm, the film may lack stiffness, making it difficult to handle in the processing steps. If it is 188 μm or more, it may be difficult to prevent deterioration of light transmittance and haze value. Furthermore, the stiffness of the film may make it difficult to handle as a roll product when a positive-type photosensitive resist layer is applied, which may also worsen economic efficiency.

[0029] The lamination thickness of the b layer, which preferably constitutes the surface of the polyester film, is preferably 0.05 μm or more and less than 2 μm, and more preferably 0.1 μm or more and less than 1.8 μm. If it is less than 0.1 μm, the shedding of particles added to the polyester layer becomes significant, and if it is 2 μm or more, in order to prevent the deterioration of the haze mentioned above, it becomes necessary to further reduce the average diameter and amount of added particles, which may make it difficult to achieve both the desired processing characteristics and the reduced thickness.

[0030] The film of the present invention may contain particles to the extent that the effects of the present invention can be obtained. Organic and inorganic particles can be used as the particles, but examples include silicon dioxide, calcium carbonate, agglomerated alumina, aluminum silicate, mica, clay, talc, and barium sulfate. Examples of organic particles include polyimide resins, olefins or modified olefin resins, crosslinked polystyrene resins, and silicone resins. When using these particles, surface modification of the particle surface with a surfactant or the like to improve affinity with polyester is preferable in order to suppress increases in light transmittance and haze value, as this suppresses void formation around the added particles. Furthermore, particles with a shape close to spherical and with a small difference in refractive index from polyester are preferable in order to suppress scattered light when ultraviolet light passes through the film layer. Colloidal silica and organic particles are particularly preferred, and silicone particles and crosslinked polystyrene particles are even more suitable. Among these, crosslinked polystyrene particles made of styrene-divinylbenzene copolymer, prepared by emulsion polymerization, are preferred because their particle shape is close to a perfect sphere, their particle size distribution is uniform, and uniform protrusion formation is possible.

[0031] In addition to the aforementioned particles, aggregated alumina can also be included. Here, aggregated alumina refers to a mixture of several to several hundred particles with an average primary particle diameter of 5 nm or more and less than 30 nm. It is more preferable that the average primary particle diameter of the aggregated alumina is 8 nm or more and less than 15 nm. The aggregated alumina can be produced from anhydrous aluminum chloride by flame hydrolysis or hydrolysis of alkoxide alumina. As for the crystalline forms of aggregated alumina, δ-type, θ-type, γ-type, etc., are known, but δ-type alumina is particularly suitable for use. These aggregated alumina can be used by adding them during polyester polymerization, but for example, aggregated alumina with an average secondary particle diameter of 0.01 μm or more and less than 0.2 μm can be obtained by grinding and dispersing it in a sand grinder or similar device as part of the ethylene glycol slurry, which is part of the raw materials for polyester polymerization, and then performing microfiltration. When the agglomerated alumina obtained in this way is added to the film, it is arranged in the planar direction by biaxial stretching, so it does not form substantial protrusions, has little effect on surface roughness, and has good permeability, so the increase in haze value can be suppressed. By including agglomerated alumina, a significant surface reinforcement effect on the film is obtained, abrasion resistance is improved, and dent defects that occur when in contact with the roll during stretching are suppressed. When using a laminated polyester film, it is preferable to include the agglomerated alumina in the polyester film that constitutes the surface layer (layer b), and the content is preferably 0.1% by mass or more and less than 5% by mass of the total polyester film.

[0032] It is preferable that the resist pattern wall does not contain particles with a volume-average particle size of 0.150 μm or larger. If particles with a volume-average particle size of 0.150 μm or larger are included, the surface irregularities and particle aggregation can cause the angle of incidence of light during the exposure process to become uneven, leading to light scattering and potentially causing irregularities on the resist pattern wall.

[0033] The particle size of particles contained on the film surface is measured as follows: The polymer is removed from the film using a low-temperature plasma ashing treatment method to expose the particles. The treatment conditions are selected to ashing the polymer but minimizing damage to the particles. The treated sample is observed with a scanning electron microscope (SEM; Hitachi, Ltd., S-4000 model), and the particle image is captured in an image analyzer (Nireco Corporation, LUZEX_AP). The equivalent circle diameter is measured to determine the volume-average particle size. The SEM magnification is appropriately selected from 5000 to 20000x depending on the particle size. The observation location is arbitrarily changed, and the volume-average particle size of at least 5000 particles is measured. The average value is taken as the volume-average particle size. Furthermore, from these results, the particle size is plotted on the x-axis with the particle size expressed in 10 nm intervals starting from 0 nm, and the number of particles with that particle size is plotted on the y-axis to create a particle size distribution graph, and the particle size with the maximum value is determined.

[0034] 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 causes resist pattern defects. However, reducing the amount of lubricant worsens the slipperiness of the polyester film, leading to a decrease in yield due to poor windability in the polyester film itself and the dry film resist manufacturing process. In this invention, a slippery resin layer is laminated on the film surface (A) on the opposite side of the resist coating layer.

[0035] The base resin used for the smooth resin layer is not particularly limited, but examples include polyester-based, acrylic-based, and polyurethane-based resins, and mixtures or copolymers thereof may also be used.

[0036] As the resin constituting the particle-free, smooth layer (X), water-dispersible polyester resins and water-dispersible acrylic resins are preferred from the viewpoint of coatability and cost, and acrylic copolymers are particularly preferred in that they achieve both smoothness and transparency.

[0037] Examples of water-dispersible acrylic resins include copolymers of monomers such as acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-methylolacrylamide, N-butoxyacrylamide, 2-hydroxyethyl methacrylate, and 2-hydroxyethyl acrylate.

[0038] In these water-dispersible acrylic resins, the average emulsion particle size is preferably in the range of 50 nm to 200 nm, and more preferably in the range of 70 nm to 150 nm. By using a water-dispersible acrylic resin with an average emulsion particle size in this range, the above-mentioned ten-point average surface roughness SRz(X) range of the smooth resin layer (X) surface can be achieved. In this invention, emulsion particle size refers to the size of the major axis of a single colloidal dispersion particle dispersed in the emulsion. After the emulsion dries, the colloidal dispersion particles of the acrylic resin scattered on the film surface are melted and aggregated through stretching and heat treatment processes, forming fine, flattened protrusions on the film surface.

[0039] Furthermore, within limits that do not impair the effects of the present invention, a cellulosic polymer such as methylcellulose or ethylcellulose may be added in an amount preferably 4 to 30 wt%, more preferably 10 to 20 wt%, relative to the solid content of the acrylic resin.

[0040] To improve the adhesion and mechanical strength of the particle-free, easily smooth resin layer of the present invention, a crosslinking binder may be added, provided that 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 crosslinks with functional groups present in acrylic resins, such as hydroxyl groups, carboxyl groups, glycidyl groups, amide groups, etc. Typical examples include methylolated or alkylolated urea-based, melamine-based, acrylamide-based, polyamide-based resins, epoxy compounds, isocyanate compounds, aziridine compounds, and oxazoline compounds. These crosslinking binders may be used alone or, in some cases, in combination of two or more types. The amount of crosslinking binder to be added is appropriately selected depending on the type of crosslinking agent, but is usually preferably 0.01 to 50 parts by weight, and more preferably 0.1 to 20 parts by weight, per 100 parts by weight of resin solids. If the amount added is less than 0.01, the effect of crosslinking is low, and if it exceeds 50 parts by weight, the coatability deteriorates, which is undesirable.

[0041] The particle-free smooth layer (X) of the film of the present invention does not contain particles. If particles are contained in the particle-free smooth layer, the aggregation of the contained particles will cause the angle of incidence of light during the exposure process to become uneven, making the light more likely to scatter. This will result in irregularities on the wall surface of the resist pattern, leading to a decrease in yield when forming high-resolution resist patterns. Furthermore, if particles are contained in the smooth resin layer, there is a risk that particles will detach from the particle-free smooth layer during the manufacturing process of the film or dry film resist, contaminating the process.

[0042] In the slippery resin layer of the film of the present invention, the average thickness is preferably 3 to 80 nm.

[0043] Preferably, the particle-free, smooth layer (X) and layer a of the film of the present invention are substantially particle-free. By not including particles in layer a, the transparency of the polyester film can be increased, and ultraviolet light can be transmitted efficiently.

[0044] The present invention has a non-silicone coating layer.

[0045] Examples of non-silicone coating agents that can be used in the present invention include long-chain alkyl group-containing resins, olefin resins, and wax-based compounds. Among these, long-chain alkyl group-containing resins are preferred because they can provide good peelability.

[0046] The long-chain alkyl group-containing compound may use commercially available non-silicone mold release agents. Specifically, the "Ashiorezin" (registered trademark) series of long-chain alkyl compounds manufactured by Ashio Sangyo Co., Ltd., and the "■Zem" series of water-soluble long-chain alkyl compounds manufactured by Chukyo Yushi Co., Ltd. can be used. The non-silicone coating preferably has an alkyl group with 12 or more carbon atoms, and more preferably has an alkyl group with 16 or more carbon atoms. By increasing the number of carbon atoms in the alkyl group to 12 or more, hydrophobicity is enhanced, which allows for more sufficient mold release performance. If the number of carbon atoms in the alkyl group is less than 12, the mold release performance may be insufficient. There is no particular upper limit to the number of carbon atoms in the alkyl group, but it is preferable to have 25 or less because it is easier to manufacture.

[0047] In the film of the present invention, the film haze is preferably 0.4% or less, and more preferably 0.3% or less. If the film haze exceeds 0.4%, the scattering of ultraviolet light by the polyester film, which is the support for the resist layer, becomes large when the resist layer is laminated onto the polyester film and then exposed by irradiation with ultraviolet light. This can result in distortion or omissions in the resist patterning after development, deterioration of the condition of the resist pattern walls, or inhibition of the transmittance of the polyester film.

[0048] In the film of the present invention, a dimensional change rate within the following range is preferable because it suppresses the occurrence of distortion and wrinkles due to thermal shrinkage during the DFR processing step. The dimensional change rate can be achieved by appropriately adjusting the conditions such as relaxation and heat treatment in the film formation conditions using known methods. At 150°C, the dimensional change rate is preferably 3.0% or less in the longitudinal direction and 2.0% or less in the width direction, and more preferably 0.5% to 2.8% in the longitudinal direction and 0.8% to 1.8% in the width direction. Furthermore, at 100°C, the dimensional change rate is preferably 1.0% or less in both the longitudinal and width directions, and more preferably in the range of 0.1% to 0.8%. If the dimensional change rate falls below the lower limit of the above range, flatness defects due to sagging will occur when applying the resist layer or during lamination, and if it exceeds the upper limit, shrinkage will occur in a corrugated iron-like pattern when applying the resist layer, resulting in flatness defects. In either case, unevenness may occur in the coating thickness of the resist layer.

[0049] Furthermore, the film of the present invention preferably has a strength (hereinafter referred to as the F-5 value) of 70 MPa or more and less than 150 MPa when the film is stretched by 5% in the longitudinal direction. If the F-5 value in the longitudinal direction is less than 70 MPa, processing characteristics may deteriorate due to insufficient strength, such as the occurrence of scratches. On the other hand, if the F-5 value in the longitudinal direction is 150 MPa or more, it may be difficult to achieve a balance with 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.

[0050] Furthermore, it is preferable that the F-5 value in the width direction be 80 MPa or more and less than 160 MPa. If the F-5 value in the width direction is less than 80 MPa, processing characteristics may deteriorate due to the occurrence of scratches due to insufficient strength, and if it is 160 MPa or more, it may be difficult to achieve compatibility with the F-5 value in the longitudinal direction. Preferably, it is 90 MPa or more and less than 150 MPa, and more preferably 100 MPa or more and less than 140 MPa.

[0051] Furthermore, the longitudinal breaking strength is preferably 200 MPa or more and less than 360 MPa, and more preferably 220 MPa or more and less than 340 MPa. The widthwise breaking strength is preferably 260 MPa or more and less than 420 MPa, and particularly preferably 280 MPa or more and less than 400 MPa. The above F-5 value and breaking strength can be achieved by appropriately adjusting the stretching temperature and stretching ratio in the longitudinal and transverse directions.

[0052] Next, the method for manufacturing the film of the present invention will be described, but it is not limited thereto. As a method for incorporating inert particles into polyester in melt film formation by co-extrusion, for example, inert particles are dispersed in a predetermined proportion in the form of a slurry in ethylene glycol, which is a diol component. After high-precision filtration that can capture 95% or more of coarse particles, for example, with a major diameter of 2 μm or more or 5 μm or more, this ethylene glycol slurry is added at any stage before the completion of polyester polymerization. When adding the particles, for example, it is preferable to add the aqueous sol or alcohol sol obtained during particle synthesis without drying it first, as this improves particle dispersibility and suppresses the generation of coarse protrusions. Alternatively, a method of directly mixing the aqueous slurry of particles with a predetermined polyester pellet and supplying it to a vented twin-screw compounding extruder to knead it into the polyester is also effective for achieving the effects of the present invention. As a method for adjusting the particle content, it is effective to prepare a master pellet with a high concentration of particles using the above method and then dilute it with PET that substantially does not contain particles during film formation to adjust the particle content.

[0053] In this way, particle-containing master pellets and pellets substantially free of particles, prepared for each layer, are mixed in a predetermined ratio, dried, and then supplied to a known melt lamination extruder under a nitrogen stream or reduced pressure so as not to reduce the intrinsic viscosity. In the production of the biaxially oriented laminated polyester film of the present invention, single-screw or twin-screw extruders can be used. In addition, a vented extruder equipped with a vacuum line can be used to eliminate the pellet drying process. Furthermore, when an intermediate layer is provided, the extrusion volume is the largest, so a so-called tandem extruder can be used, in which the function of melting the pellets and the function of maintaining the molten pellets at a constant temperature are divided between the extruders. For extruding the layers that constitute the surface of the biaxially oriented laminated polyester film of the present invention, it is preferable to use a twin-screw vented extruder because it can maintain good particle dispersibility and suppress particle aggregation.

[0054] The polymer, melted and extruded in the extruder, is filtered. Since even very small foreign matter can become large protrusion defects if it enters the film, it is effective to use a high-precision filter that captures 95% or more of foreign matter, for example, with a major diameter of 2 μm or more or 5 μm or more. Next, the polymer is extruded into a sheet from a slit-shaped slit die and cooled and solidified on a casting roll to create an unstretched film. That is, multiple extruders, multiple layers of manifolds or confluence blocks (for example, confluence blocks with a rectangular confluence section) are used for lamination, the sheet is extruded from the die, and cooled on a casting roll to create an unstretched film. In this case, installing a static mixer and a gear pump in the polymer flow path is effective from the viewpoint of stabilizing back pressure and suppressing thickness fluctuations.

[0055] The stretching method may be 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, and more preferably 100°C or higher and less than 115°C. A stretching temperature below 95°C is undesirable because the film is prone to tearing, and a stretching temperature above 120°C is undesirable because the film surface is prone to thermal damage. Furthermore, from the viewpoint of preventing uneven stretching and scratches, it is effective to provide a preheating zone before stretching and heat in stages, and the preheating temperature in the longitudinal direction is preferably 65°C to 130°C, and more preferably 70°C to 110°C.

[0056] The elongation 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.

[0057] The resulting uniaxially oriented film is cooled. The cooling temperature is preferably between 18°C ​​and 40°C, and more preferably between 21°C and 35°C. Cooling stabilizes the width dimensional stability, preventing scratches on the film transport roll and suppressing wrinkles, even if the film surface is smooth as in the present invention.

[0058] The film is then stretched in the width direction in a known stent oven to become a biaxially oriented film. The film is held by clips that run on rails inside the stent oven and heated again in the oven to a temperature above the intermediate glass transition temperature of the resin, and stretched in the width direction as the rails on which the clips run expand. At this time, the stretching ratio in the width direction is preferably 3.2 times or more and less than 5 times, and more preferably 4.0 times or more and less than 4.6 times.

[0059] Here, it is important to heat the film in stages in order to control the surface roughness of the film. By heating the uniaxially oriented film to 95°C to 120°C before stretching it in the width direction, and then stretching the film in the width direction at 105°C to 115°C once it has been sufficiently heated above the intermediate glass transition temperature of the resin, the stretching of the film becomes easier, and minute stretching irregularities caused by particles forming the film surface can be suppressed.

[0060] Next, the obtained biaxially oriented film can be heat-treated. The heat treatment may be performed in the same stent oven immediately following the widthwise stretching, or in a different oven from the one used for widthwise stretching. The heat treatment temperature is preferably between 190°C and 250°C. Heat treatment is preferable because it improves dimensional stability when exposed to high temperatures during subsequent processing steps or when used as the final product. It is also preferable to further improve dimensional stability by relaxing the film in the widthwise direction by more than 0% and less than or equal to 8% during the heat treatment.

[0061] It is preferable to cool the biaxially stretched film when it is removed from the oven. The cooling temperature is preferably 60°C to 120°C, and more preferably 70°C to 110°C. Cooling stabilizes the width dimension, and even if the film surface is smooth as in the present invention, it is possible to prevent scratches on the film transport roll and suppress wrinkles.

[0062] Next, the edges are cut and the film is wound up to obtain an intermediate product. During this transport process, the film thickness is measured, and this data is fed back and used to adjust the film thickness by adjusting the die thickness, etc., and foreign matter is detected by a defect detector.

[0063] In the biaxially oriented laminated polyester film of the present invention, it is preferable to suppress the generation of chips when cutting the edges. A circular blade, a shear blade, or a straight blade can be used to cut the edges, but when using a straight blade, it is preferable to prevent the blade from always contacting the same spot on the film, as this suppresses blade wear. For this reason, it is preferable to have a mechanism that oscillates the blade to its upper limit. It is also preferable to provide a suction device at the film cutting site to suck up the generated chips and the shavings generated when the film edges are scraped together after cutting.

[0064] The method for constructing the slippery resin layer (X) and the non-silicone coating layer (Y) is not particularly limited, but the slippery resin layer (X) and the non-silicone coating layer (Y) are formed using an in-line coating method in which the coating material for the slippery resin layer (X) and the coating material for the non-silicone coating layer (Y) are laminated before the lateral stretching process, and then dried in a subsequent process.

[0065] The method for providing the slippery resin layer (X) is the metering bar coating method, in which the film is subjected to surface treatment such as corona discharge treatment or plasma discharge treatment in air or various other atmospheres as needed before coating.

[0066] The non-silicone coating layer (Y) is formed by applying the coating agent using the metering bar coating method.

[0067] The intermediate product is slit to the appropriate width and length in a slitting process and wound up to obtain a roll of the biaxially oriented laminated polyester film of the present invention. When cutting the film in the slitting process, the same cutting method as for cutting the edges described above can be selected.

[0068] The intermediate product is slit to a desired width to obtain the biaxially oriented laminated polyester film of the present invention. The biaxially oriented laminated polyester film thus obtained has good permeability and slipperiness, and can therefore be suitably used as a dry film resist support.

[0069] In particular, as the circuit wiring of electronic information equipment is becoming increasingly miniaturized, films used as dry film resist supports for circuit wiring fabrication require improved wiring depiction by minimizing light scattering on the film surface during ultraviolet exposure.

[0070] The biaxially oriented laminated polyester film of the present invention is preferable to be used so that it is exposed to ultraviolet light from the side with the smooth resin layer (X), because the smooth resin layer (X) can suppress the effects of light scattering and other factors during ultraviolet exposure. [Examples]

[0071] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0072] (Measurement method) (1) Measurement of the thickness of the laminated film and each layer The total thickness of the laminated film was measured at 10 random points using a micrometer, and the average value was used. The cross-section of the laminated film was cut into ultrathin sections and observed using a transmission electron microscope (TEM) at magnifications of 10,000 to 1,000,000x, with staining methods using RuO4 staining, OsO4 staining, or double staining of both. Photographs were taken from these cross-sectional images. The thicknesses of the smooth resin layer (X), and the polyester film layers a and b were measured from these cross-sectional images.

[0073] (2) Number of protrusions with a height of 50 nm or more in the non-silicone coating layer After microscopic image observation and image processing of the non-silicone coated layer surface, particle analysis is performed using the built-in surface analysis software VS-Viewer Version 10.0.3.0 under the following conditions. The number of particles (particles) displayed on the "Particle Analysis" screen, which detects particles at a height threshold of 50 nm (R50 nm, height threshold setting value: 0.050 μm), is divided by the measurement area (113 μm × 113 μm) to determine the number of protrusions (particles / mm²) with a height of 50 nm or more. 2 )

[0074] (Particle analysis conditions) The protrusion analysis process will be performed under the following conditions. ·Analysis type: sudden analysis Image correction: None • Processing height threshold: 0.05 μm Particle shaping: None • Reference height: Zero plane (average plane) • Subject to evaluation • Height / Depth: -10000μm ≤ h ≤ 10000μm • Longest diameter: -10000 μm ≤ d ≤ 10000 μm Volume: V ≥ 0.0000 μm 3 Aspect ratio: r≧0.0000 • Histogram: 50 divisions

[0075] The same procedure was performed on all 30 fields of view, and the average value was used to determine the number of protrusions with a height of 50 nm or more in the sample (N50 nmA / mm²). 2 ) (Reference height: zero plane (average plane))

[0076] As the zero plane (average plane) for setting the reference height, the plane of the average height (Ave) obtained by observing a microscope image using the method described above and applying the image processing described above to the measurement image (113 μm × 113 μm) is used, which is automatically determined by the following formula.

[0077]

number

[0078] • lx: Range length in the X direction in each measurement image after the aforementioned image processing. ·ly: Y-direction range length in each measurement image after the aforementioned image processing. h(x,y): Height at each image point (x,y) in the measured image after the image processing described above.

[0079] (3) Number of coarse foreign objects and number of gelled objects A biaxially oriented laminated polyester film was cut to 4cm x 4cm and attached to a slit plate with holes measuring 7.5mm in the longitudinal direction and 1.1mm in the width direction. The area of ​​the slit holes was observed using an optical microscope (NICON-LV100) with a 20x objective lens, covering the thickness of the film. A white light source and a polarized light source were used as light sources. The number of foreign objects with a major axis of 1 μm or larger detected was measured after 10 observations with different slit holes. Foreign objects observed using the white light source of the optical microscope were defined as coarse foreign objects, and foreign objects observed using the polarized light source were defined as gels. The major axis of each foreign object refers to the longest length measured by the optical microscope.

[0080] (4) Particle size The particle size of particles contained on the film surface was measured as follows: The polymer was removed from the film using a low-temperature plasma ashing treatment method to expose the particles. The treatment conditions were selected to ashing the polymer while minimizing damage to the particles. The treated sample was observed with a scanning electron microscope (SEM; Hitachi, Ltd., S-4000 model), and the particle image was captured in an image analyzer (Nireco Corporation, LUZEX_AP). The equivalent circle diameter was measured to determine the volume-average particle size. The SEM magnification was appropriately selected from 5000 to 20000x depending on the particle size. The volume-average particle size of at least 5000 particles was measured at arbitrarily changed observation points, and the average value was taken as the volume-average particle size. Furthermore, from these results, a particle size distribution graph was created by plotting the particle size, expressed in 10 nm intervals with 0 nm as the starting point, on the x-axis and the number of particles with that particle size on the y-axis, and the particle size with the maximum value was determined.

[0081] (5) Visual inspection of resist resolution The visual evaluation method for the resolution of the resist in the biaxially oriented laminated polyester film of the present invention was performed using the following procedure.

[0082] (i) A 7 μm thick resist layer was fabricated on a 6-inch Si wafer that had been mirror-polished on one side by coating it with Tokyo Ohka Co., Ltd.'s negative resist "PMER N-HC600" and rotating it with a large spinner. Next, a preheat treatment was performed for approximately 20 minutes at a temperature of 70°C using a nitrogen-circulating ventilated oven.

[0083] (ii) The non-silicone coated layer was placed on top of the resist layer with the non-silicone coated layer facing the resist layer, and a polyester film was laminated onto the resist layer using a rubber roller. A photomask patterned with chromium metal was then placed on top of the polyester film, and exposure was performed on the photomask using an I-line stepper.

[0084] (iii) After peeling the polyester film from the resist layer, the resist layer was placed in a container with developer N-A5 and developed for approximately 1 minute. After that, it was removed from the developer and washed with water for approximately 1 minute.

[0085] (iv) The L / S (μm) (Line and Space) state of the resist pattern created after development was observed at 1500x magnification using a scanning electron microscope (SEM). The resolution of the resist was evaluated according to the following criteria. A rating of B or higher is considered to be at a practical level. S:L / S = 5 / 5μm can be clearly observed. A: L / S = 5 / 5 μm cannot be clearly confirmed, but L / S = 8 / 8 μm can be clearly confirmed. While B:L / S = 8 / 8 μm cannot be clearly confirmed, L / S = 10 / 10 μm can be clearly confirmed. The C:L / S ratio of 10 / 10 μm cannot be clearly confirmed. (Not applicable to production).

[0086] (6) Visual inspection of the surface condition of the resist after exposure following peeling. The visual evaluation method for the surface state of the resist in the biaxially oriented laminated polyester film of the present invention was performed using the following procedure.

[0087] (i) A 7 μm thick resist layer was fabricated on a 6-inch Si wafer that had been mirror-polished on one side by coating it with Tokyo Ohka Co., Ltd.'s negative resist "PMER N-HC600" and rotating it with a large spinner. Next, a preheat treatment was performed for approximately 20 minutes at a temperature of 70°C using a nitrogen-circulating ventilated oven.

[0088] (ii) The non-silicone coating layer was placed in contact with the resist layer, and a polyester film was laminated onto the resist layer using a rubber roller. The polyester film was then peeled off from the resist layer, and a photomask patterned with chromium metal was placed on top of it. Exposure was then performed on the photomask using an I-line stepper.

[0089] (iii) After peeling the polyester film from the resist layer, the resist layer was placed in a container with developer N-A5 and developed for approximately 1 minute. After that, it was removed from the developer and washed with water for approximately 1 minute.

[0090] (iv) The L / S (μm) (Line and Space) state of the resist pattern created after development was observed at 1500x magnification using a scanning electron microscope (SEM). The resolution of the resist was evaluated according to the following criteria. A rating of B or higher is considered to be at a practical level. S: No transfer marks are visible on the surface. A: There are slight transfer marks on the surface, but no defects such as missing circuits. B: Transfer marks are visible on the surface, and slight defects in the circuit are visible. C: There are many transfer marks, and the circuit is missing or broken. (Not suitable for production).

[0091] (7) Handling properties (slipperiness evaluation) of the resist film Using the biaxially oriented laminated polyester film of the present invention as a support, a resist layer made of a positive-type photosensitive resin was coated onto the surface (B) to produce a resist film. One sample was cut out from there, and after static electricity was removed from the surface of the sample, it was placed so that the resist layer was in contact with the surface of a glass plate. Next, the edges of the film were fixed, and a 6-inch bare wafer was placed on the particle-free slip-free layer. A load of 1 kg (normal force of 10 N) was applied from above the bare wafer, and it was moved 70 mm at 100 mm / min. The tension between the bare wafer and the particle-free slip-free layer of the biaxially oriented polyester film of the present invention was measured, and the slipperiness was evaluated according to the following criteria. An evaluation of B or higher is considered to be a practical level. S: 0N or higher and less than 3N (Possesses appropriate slipperiness and good handling.) A: 3N to less than 5N (Slightly poor slipperiness and slightly inferior handling.) B: 6N or higher (Poor slipperiness, difficult to handle, unsuitable for production)

[0092] (8) Evaluation of wiring defects in conductor circuits The method for evaluating wiring defects that contribute to the yield of a conductor circuit when the film of the present invention is used as a support for a dry film resist was performed using the following procedure.

[0093] (i) A 7 μm thick resist layer was fabricated on a 6-inch Si wafer that had been mirror-polished on one side by coating it with Tokyo Ohka Co., Ltd.'s negative resist "PMER N-HC600" and rotating it with a large spinner. Next, a preheat treatment was performed for approximately 20 minutes at a temperature of 70°C using a nitrogen-circulating ventilated oven.

[0094] (ii) The polyester film was placed on top of the resist layer with surface (B) 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 bonded to the copper-clad laminate with the resist layer side in contact with the copper-clad laminate, and a photomask patterned with chromium metal was placed on surface (A), and exposure was performed on the photomask using an I-line stepper.

[0095] (iii) After peeling the polyester film from the resist layer, the resist layer was placed in a container with developer N-A5 and developed for approximately 1 minute. After that, it was removed from the developer and washed with water for approximately 1 minute.

[0096] (iv) After development, the copper-clad laminate with the resist layer remaining was immersed in a ferric chloride solution, the exposed copper was etched, and then the resist layer was peeled off to form a conductive circuit with L / S = 10 / 10 μm.

[0097] The state of the constructed conductive circuit was examined using an optical microscope (NICON LV-100) at 8.25 mm. 2 The region was observed at 500x magnification, and wiring defects in the conductor circuit were evaluated according to the following criteria. A rating of A or higher indicates a practically usable level. S: Maximum diameter size of wiring defect is less than 2.4 μm A: Maximum diameter size of wiring defects is less than 3.2 μm B: Maximum diameter size of wiring defects is less than 4.0 μm

[0098] (9) Intrinsic viscosity (IV) The value used was calculated from the solution viscosity measured at 25°C in orthochlorophenol using the following formula. ηsp / C = [η] + K[η]²·C

[0099] Here, ηsp = (solution viscosity / solvent viscosity) - 1, C is the weight of polymer dissolved per 100 ml 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.

[0100] Furthermore, when measuring the intrinsic viscosity (IV) of the polyester resin constituting the outermost polyester layer of a polyester film, the measurement is performed by scraping off the polyester resin constituting the outermost polyester layer of the polyester film.

[0101] Furthermore, when measuring the intrinsic viscosity of the polyester resin constituting the polyester layer excluding the outermost layer of the polyester film, the ratio of the layer thicknesses of each layer of the polyester film is determined using 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 excluding the outermost layer is determined by weight-proportional distribution. In addition, if there are insoluble substances such as inorganic particles in the solution in which the sample is dissolved, the solution is filtered and weighed, and the weight of the filtered material is subtracted from the weight of the sample to perform a correction to determine the weight of the sample.

[0102] (10) S / N ratio (dB) of thickness unevenness over a length of 2000m Using a wound biaxially oriented polyester film roll as a sample, the thickness of an arbitrary 2000m section of the film roll, wound at a speed of 100m / min, was measured using a Keyence SI-T spectral interference displacement type multilayer film thickness analyzer and a NR-500 multi-input data logger. The specifications of each instrument and the measurement conditions are as follows.

[0103] (SI-T specification) • Controller with display unit SI-T1000V • Sensor head, long-distance thickness measurement type SI-T80 • Spectroscopic Unit SI-T80U • Ultra-compact switching power supply CA-U4 ·Measurement software SI-Navigator T (SI-T measurement conditions) • Measurement mode: Standard • Measurement type: Displacement • Measurement mode: Normal • Filter type: Moving average • Average number of times: 1 (NR-500 specifications) • Measuring instrument main unit, interface unit NR-500 • High-speed analog measurement unit NR-HA08 (NR-500 measurement conditions) Input range: ±10V • Average number of times: 2 • Sampling period: 10ms • Edge trigger: Not used

[0104] For the obtained film thickness data (n=120,000), a 10-point moving average was calculated, and the thickness variation over 2000m was determined based on the following formula. Thickness variation (%) at 2000m = (Maximum value - Minimum value) / Total average value × 100.

[0105] (13) Evaluation of the cutting state of Si wafers The method for evaluating the cutting condition that contributes to the yield of conductive circuits when the biaxially oriented laminated polyester film of the present invention is used as a support for a dry film resist was performed using the following procedure.

[0106] (i) A 7 μm thick resist layer was fabricated on a 6-inch Si wafer that had been mirror-polished on one side by coating it with Tokyo Ohka Co., Ltd.'s negative resist "PMER N-HC600" and rotating it with a large spinner. Next, a preheat treatment was performed for approximately 20 minutes at a temperature of 70°C using a nitrogen-circulating ventilated oven.

[0107] (ii) The polyester film was placed on top of the resist layer with surface (B) 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 bonded to the copper-clad laminate with the resist layer side in contact with the copper-clad laminate, and a photomask patterned with chromium metal was placed on surface (A), and exposure was performed on the photomask using an I-line stepper.

[0108] (iii) After peeling the polyester film from the resist layer, the resist layer was placed in a container with developer N-A5 and developed for approximately 1 minute. After that, it was removed from the developer and washed with water for approximately 1 minute.

[0109] (iv) After development, the copper-clad laminate with the resist layer remaining was immersed in a ferric chloride solution, the exposed copper was etched, and then the resist layer was peeled off to form a conductive circuit with L / S = 10 / 10 μm. The state of the conductive circuit when it was cut to a specific size was measured using an optical microscope (NICON LV-100) at 8.25 mm. 2 The region was observed at 500x magnification, and the cut portion of the conductor circuit was evaluated according to the following criteria. A rating of B or higher indicates a practical level of performance. S: No burrs or chips were observed at all. A: Although metal shavings were observed, the cutting process was completed without any problems. B: Although burrs and metal shavings were generated, the cutting was successful. C: Burrs and metal shavings were generated, causing some chipping in the circuit.

[0110] (raw materials) (Creation of Polyester A) 86.5 parts by weight of terephthalic acid and 37.1 parts by weight of ethylene glycol were esterified at 255°C while distilling off water. After the esterification reaction was complete, 0.0175 parts by weight of tetrabutylphosphonium p-toluenesulfonate, 0.0090 parts by weight of manganese acetate tetrahydrate, and 0.0072 parts by weight of germanium dioxide were added. Subsequently, under vacuum, the mixture was heated to 290°C and the temperature was increased to carry out a polycondensation reaction to obtain polyester pellets with an intrinsic viscosity of 0.63 dl / g (Polyester A).

[0111] (Creation of Polyester B) In the same manner as in the preparation of polyester A described above, when producing polyester, after transesterification, spherical silica with a volume-average particle size of 0.06 μm, a volume-shape coefficient f=0.51, and a Mohs hardness of 7 was added, and a polycondensation reaction was carried out to obtain a silica-containing master pellet (polyester B) containing 1.0% by weight of the particles relative to the polyester. The spherical silica used was obtained by stirring a mixed solution of ethanol and ethyl silicate, adding a mixed solution of ethanol, pure water, and ammonia water as a basic catalyst to this mixed solution, stirring the resulting reaction solution to carry out the hydrolysis reaction of ethyl silicate and the polycondensation reaction of the hydrolysis product, and then stirring after the reaction to obtain monodisperse silica particles.

[0112] (Creation of Polyester C) In the same manner as in the preparation of polyester A described above, when producing polyester, after transesterification, spherical silica with a volume-average particle size of 0.2 μm, a volume-shape coefficient f=0.51, and a Mohs hardness of 7 was added, and a polycondensation reaction was carried out to obtain a silica-containing master pellet (polyester C) containing 2% by weight of the particles relative to the polyester. The spherical silica used was obtained by stirring a mixed solution of ethanol and ethyl silicate, adding a mixed solution of ethanol, pure water, and ammonia water as a basic catalyst to this mixed solution, stirring the resulting reaction solution to carry out the hydrolysis reaction of ethyl silicate and the polycondensation reaction of the hydrolysis product, and then stirring after the reaction to obtain monodisperse silica particles.

[0113] (Creation of Polyester D) As agglomerated alumina, δ-type alumina was used in a 10% ethylene glycol slurry, which was then crushed and dispersed using a sand grinder. The slurry was further filtered using a 3 μm filter with a collection efficiency of 95%. This was added to a transesterification reaction product prepared in the same manner as for the preparation of polyester A, and subsequently antimony trioxide was added. A polycondensation reaction was carried out to obtain a master pellet containing 1.5% by weight of agglomerated alumina and having an intrinsic viscosity of 0.62 dl / g (polyester D).

[0114] (Creation of Polyester E) 86.5 parts by weight of terephthalic acid and 37.1 parts by weight of ethylene glycol were esterified at 255°C while distilling off water. After the esterification reaction was complete, 0.02 parts by weight of trimethyl phosphate, 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, under vacuum, the mixture was heated to 290°C and the temperature was increased to carry out a polycondensation reaction to obtain polyester pellets with an intrinsic viscosity of 0.63 dl / g (Polyester E).

[0115] (Release agent) • Long-chain alkyl group-containing resin (a) 200 parts xylene and 600 parts octadecyl isocyanate were added to a four-necked flask and heated with stirring. From the moment the xylene began to reflux, 100 parts of polyvinyl alcohol with an average degree of polymerization of 500 and a degree of saponification of 88 mol% were added in small amounts at 10-minute intervals over approximately 2 hours. After the addition of polyvinyl alcohol was completed, reflux was continued for another 2 hours to terminate the reaction. The reaction mixture was cooled to approximately 80°C and then added to methanol. The reaction product precipitated as a white precipitate, which was filtered off. 140 parts xylene was added and heated to completely dissolve it. This process of adding methanol again to precipitate was repeated several times, and the precipitate was washed with methanol and dried and ground to obtain a long-chain alkyl group-containing resin (a: polymethylene as the main chain with C18 alkyl groups in the side chains). This was diluted with water to a concentration of 20% by mass. • Acrylic resin (b)

[0116] In a stainless steel reaction vessel, methyl methacrylate (α), hydroxyethyl methacrylate (β), and urethane acrylate oligomer (manufactured by Negami Kogyo Co., Ltd., Art Resin® UN-3320HA, with 6 acryloyl groups) (γ) were charged in a mass ratio of (α) / (β) / (γ) = 94 / 1 / 5. As an emulsifier, 2 parts by mass of sodium dodecylbenzenesulfonate were added to 100 parts by mass of the total of (α) to (γ), and the mixture was stirred to prepare Mixture 1. Next, a reaction apparatus equipped with a stirrer, reflux condenser, thermometer, and dropping funnel was prepared. 60 parts by weight of the above Mixture 1, 200 parts by weight of isopropyl alcohol, and 5 parts by weight of potassium persulfate as a polymerization initiator were charged into the reaction apparatus and heated to 60°C to prepare Mixture 2. Mixture 2 was maintained at 60°C for 20 minutes. Next, a mixture 3 was prepared consisting of 40 parts by weight of mixture 1, 50 parts by weight of isopropyl alcohol, and 5 parts by weight of potassium persulfate. Subsequently, mixture 3 was added dropwise to mixture 2 over 2 hours using a dropping funnel to prepare mixture 4. After that, mixture 4 was kept heated at 60°C for 2 hours. After the obtained mixture 4 was cooled to below 50°C, it was transferred to a container equipped with a stirrer and a vacuum device. 60 parts by weight of 25% aqueous ammonia and 900 parts by weight of pure water were added, and the isopropyl alcohol and unreacted monomers were recovered under reduced pressure while heating at 60°C to obtain acrylic resin (b) dispersed in pure water.

[0117] (Non-silicone coated paint) As described above, a non-silicone coating paint was prepared by mixing the long-chain alkyl group-containing resin (a) and acrylic resin (b) in a ratio of 75 parts by weight of (a) and 25 parts by weight of (b). Furthermore, in order to improve the applicability to polyester film, a nonionic surfactant ("SN Wet 366" manufactured by Sunopco Co., Ltd.) was added in an amount of 0.1 parts by weight per 100 parts by weight of the total coating composition.

[0118] (Example 1) After mixing the raw materials for each layer according to the formulations shown in Table 1 in a blender, the mixed raw materials for layer b were supplied to a twin-screw extruder with a vent for layer b, and the raw materials for layer a were dried under reduced pressure at 120-140°C for more than 1 hour and supplied to a single-screw extruder for layer a. Subsequently, the layers were melt-extruded at 275°C, filtered using a high-precision filter that captures more than 95% of foreign matter larger than 5 μm for layer a, and filtered using a high-precision filter that captures more than 95% of foreign matter larger than 2 μm for layer b. The layers were then combined and laminated using a rectangular two-layer confluence block to form a two-layer laminate consisting of layer a and layer b. After that, the films were wound onto a casting drum with a surface temperature of 23°C using an electrostatic casting method via a slit die maintained at 285°C, and cooled and solidified to obtain an unstretched laminated film.

[0119] The unstretched film was preheated with a heated roll at 68-99°C, then stretched four times its length in the longitudinal direction at 113-115°C using a stretching roll with a surface roughness Ra of 0.2 μm. Subsequently, the film was cooled by lowering the temperature by 88-90°C from the stretching temperature. After that, a 0.4% solid content solution of a water-dispersible acrylic copolymer (intermediate glass transition temperature 80°C, emulsion particle size 90-120 nm) was applied to the surface of layer a of the uniaxially stretched film using the metering bar coating method as a particle-free smooth layer. Furthermore, a non-silicone coating paint was subsequently applied to the surface of layer b using the metering bar coating method. Subsequently, the film was stretched 4.3 times in the width direction under hot air at 103-112°C using a stenting machine, then heat-treated at 222°C for 3 seconds under constant tension, and then subjected to a relaxation treatment of 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 and a 10 nm layer of slippery resin laminated on top. 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 obtained films are shown in Table 3. In all evaluations, the rating was S, indicating good results.

[0120] (Examples 2-3) A polyester film roll was obtained using the same method as in Example 1, except that the number of protrusions on the non-silicone coated surface was changed by altering the particle concentration of layer b. In Example 2, the surface condition of the resist was judged as A due to the increased number of protrusions in the non-silicone coated layer, and in Example 3, the handling performance of the resist was also judged as A, but these were at an acceptable level.

[0121] (Example 4) In Example 1, polyester E was used instead of polyester A to obtain a polyester film roll. Because polyester E using antimony as the polymerization catalyst was used, the number of coarse protrusions and gelled particles increased, resulting in an A rank in the wiring defect evaluation and an A rank in the resist resolution evaluation, as shown in Table 3, but these were at an acceptable level.

[0122] (Examples 5-7) A polyester film roll was obtained in the same manner as in Example 1, except that the overall thickness of the polyester film was changed from 16 μm to 10 μm, 100 μm, and 188 μm.

[0123] (Example 8) A polyester film roll was obtained in the same manner as in Example 1, except that the polymer compositions of the three layers were as shown in Table 1.

[0124] (Example 9) As shown in Table 1, a polyester film roll was obtained in the same manner as in Example 1, except that the concentration of polyester B was changed from 10% to 30%.

[0125] (Example 10) A polyester film roll was obtained using the same method as in Example 1, except that the raw material composition of layer b was changed as shown in Table 1. Although the surface condition deteriorated after peeling exposure due to the increased number of protrusions in the non-silicone coating layer, the result was B, which is an acceptable level.

[0126] (Comparative Examples 1 and 2) A polyester film roll was obtained in the same manner as in Example 1, except that the raw material composition of layer b was as shown in Table 1. Due to the increased number of protrusions on the non-silicone coated surface, the surface condition of the resist after exposure was poor, resulting in a C rating and failure to pass the test.

[0127] [Table 1]

[0128] [Table 2]

[0129] [Table 3]

Claims

1. The polyester film has a particle-free, smooth-slip layer (X) on one side and a non-silicone coating layer (Y) on the opposite side, with 200 coarse protrusions of 50 nm or larger per mm on the surface of the non-silicone coating layer. ２ A film for a dry film resist support, characterized by the following features.

2. When observing a region measuring 7.5 mm in length and 1.1 mm in width using a white light source with an optical microscope, the number of coarse foreign objects with a major axis of 1 μm or larger was 20 per cm. ２ The following is observed: the number of gels with a major axis of 1 μm or larger when observed using a polarized light source is 2 per cm. ２ The following is a film for a dry film resist support according to claim 1.

3. The film for a dry film resist support according to claim 1, characterized in that the thickness of the polyester film is 10 μm or more and 188 μm or less.

4. The film for a dry film resist support according to claim 1, wherein the polyester film is a laminated polyester film of at least two layers, and the layer in contact with the non-silicone coating layer (Y) contains particles with a particle size of 0.1 μm or less in an amount of 0.5% by mass or more and 2% by mass or less relative to the film, and the thickness of the layer containing the particles is 0.05 to 2 μm.

5. A film for a dry film resist support according to claim 1, characterized by exposure after peeling.

6. The biaxially oriented polyester film for dry film resist support according to claim 1, characterized in that the moving average of the thickness unevenness when the thickness unevenness over a longitudinal direction of 2000 m of the film is 6.0% or less.

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