JP4471611B2 - Polyester film for dry film resist for high resolution - Google Patents

Description

  The present invention relates to a film for dry film resist (hereinafter referred to as DFR) suitable for manufacturing packages such as printed wiring boards, lead frames, BGAs, and CSPs. The present invention relates to a DFR film suitable for manufacturing a required substrate. Specifically, by providing a film with high transparency and extremely flat surface roughness with an antistatic and easy-to-slip coating layer, the surface of the base film can be prevented from being damaged by electrostatic discharge on the film surface. Prevents dirt and dust from attracting and adhering to it, preventing pattern irregularities due to adhesion of foreign matter, stabilizing quality, and workability and smoothness when winding a flat film into a roll It is related with the film for DFR excellent in processing appropriateness.

  In recent years, DFR has been widely used in the production of printed wiring circuit boards. A DFR usually consists of a support film / photoresist layer / protective film. As the support film, a polyester film excellent in mechanical properties, optical properties, chemical resistance, heat resistance, dimensional stability, flatness and the like is mainly used. The photoresist layer is a layer made of a photosensitive resin, and a polyethylene film, a polypropylene film, or a polyester film is used as the protective film. Briefly explaining how to use the DFR, the protective film is first peeled off, and the exposed photoresist layer is brought into close contact with the conductive base material affixed to the substrate. The conductive substrate is generally a copper plate. Next, a glass plate or film (referred to as a photomask) on which a circuit is printed is brought into close contact with the support film side, and light is irradiated from the photomask side. In general, ultraviolet light is used as the irradiation light. In the circuit image printed on the glass plate, light passes through a transparent portion, and the photosensitive resin of the photoresist layer reacts only to the exposed portion. Next, the glass plate and the support layer are removed, and the unexposed portion of the photoresist layer is removed using a suitable solvent or the like. Further, if etching is performed using an acid or the like, the photoresist layer is removed and the exposed conductive base material portion is removed. Thereafter, when the exposed and reacted photoresist layer is removed by an appropriate method, a conductive substrate layer is formed as a circuit on the substrate.

  Recently, the circuits to be formed have become extremely complicated, the lines have become narrower, and the intervals between them have become narrower, and it has become necessary to have high reproducibility and resolution of image formation. For this reason, the high quality came to be requested | required also with respect to the polyester film used as a support body. The polyester film used as a support needs to have a flat surface, high transparency, and low film haze. In the photoresist film, when exposing the photoresist layer, light passes through the support layer as described above. Therefore, if the transparency of the support is low, the photoresist layer is not sufficiently exposed, and if the film haze is high and the film surface roughness is rough, the resolution deteriorates due to scattering of light on the film surface and inside. Will occur.

  A polyester film having a flat surface, high transparency, and low film haze is poor in handleability in the film production process, the winding process, and the like, and is easily charged. When manufacturing a DFR by forming a photoresist layer, the use of such a charged film roll attracts minute foreign matters such as dust and dirt by the action of static electricity. In particular, when unrolling from a roll, intense charging occurs due to peeling, and adhesion of foreign matter is further increased. In addition, there is a risk of ignition by spark discharge to the photoresist organic solvent paint, and the resist at the charged part. There are problems such as increased adhesion and hindering peeling of the support film after exposure.

In order to improve the chargeability and handleability of such a film, or to improve the handleability and winding characteristics of the DFR itself, there is usually a method of incorporating particles in a polyester film and forming fine protrusions on the surface. It is used. However, when protrusions are formed by adding particles, UV rays are scattered by the protrusions and the resist surface is dented, resulting in reduced resolution and defects in the recent ultrafine wire circuit formation, and reduced film transparency. Will be. Since it has such contradictory characteristics, a method for obtaining a DFR film for high resolution satisfying transparency, chargeability, slipperiness and flatness has not been found yet.
Japanese Patent Laid-Open No. 7-333853 JP 2000-221688 A JP 2001-117237 A

  The present invention has been made in view of the above circumstances, and its solution is to prevent disasters caused by the discharge of static electricity charged on the film surface and prevent the surface of the base film from attracting and adhering dust and dirt. In order to prevent irregular patterning due to adhesion of foreign matter, to stabilize quality, and to provide a film excellent in workability, smoothness, etc. when winding a flat film into a roll. .

  As a result of various studies to achieve the above object, the present inventor has found that the above problem can be easily solved by using a film having a specific structure, and has completed the present invention.

  That is, the gist of the present invention is a film having an easy-to-slip and antistatic coating layer on at least one surface, and the average surface roughness (Ra) of the coating layer surface is 2 nm or more and less than 10 nm, the maximum surface The present invention resides in a polyester film for a dry film resist for high resolution, wherein the roughness (Rt) is 20 nm or more and less than 200 nm.

Hereinafter, the present invention will be described in detail.
The polyester referred to in the present invention is a dicarboxylic acid component constituting the polyester, such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, hexahydroterephthalic acid, 4.4'-diphenyldicarboxylic acid, adipic acid, sebacic acid And dodecanedicarboxylic acid. In particular, terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are preferable from the viewpoint of mechanical properties of the film. Examples of the glycol component constituting the polyester include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, cyclohexanedimethanol, polyethylene glycol, and the like. Can be illustrated. In particular, ethylene glycol is preferable from the viewpoint of the rigidity of the film.

  The polyester may be a copolyester obtained by copolymerizing the dicarboxylic acid component or glycol component as the third component, and may contain a trifunctional or higher polyvalent carboxylic acid component or polyol component. It may be a polyester copolymerized in a small amount within a linear range (for example, 5 mol% or less). As the polyester used in the present invention, polyethylene terephthalate or polyethylene-2,6-naphthalate is particularly preferable. Such a polyester can be produced by a conventional method, and if the intrinsic viscosity of the polyester (in orthochlorophenol, 35 ° C.) is 0.45 or more, the mechanical properties such as the tearability and rigidity of the film are good. Therefore, it is preferable.

  In addition, copolymerized polyesters such as terephthalic acid and isophthalic acid, stabilizers, antioxidants and the like can be contained in the polyester as necessary. The polyester film used in the present invention can be produced by a known method. For example, a biaxially stretched polyester film is obtained by drying a polyester resin, melting it with an extruder, extruding it from a die (such as a T-die) onto a rotating cooling drum, and quenching to produce an unstretched film. It can manufacture by extending | stretching an unstretched film to the vertical direction and a horizontal direction, and heat-setting as needed. The thickness of the polyester film is in the range of 10 to 25 μm, and preferably in the range of 10 to 18 μm.

  The film of the present invention has a slippery and antistatic coating layer on at least one surface of the film substrate. However, even if the coating layer is both surfaces, only the surface in contact with the photoresist layer, or vice versa. Although it may be only the surface, it is preferably coated on the resist opposite surface which is the surface in contact with the protective film. When the DFR is wound up in a roll shape, the resist opposite surface of the support film is in contact with the protective film, and in order to prevent peeling electrification that occurs when this roll is rewound, the surface in contact with the protective film is slippery. In addition, the effect is more remarkable with antistatic properties.

  The surface roughness Ra of the coating layer surface of the film of the present invention is in the range of 2 nm or more and less than 10 nm, preferably in the range of 2 to 7 nm. When the surface roughness Ra is 10 nm or more, the transparency of the polyester film is lowered, the light scattering on the film surface is increased, the exposure amount of ultraviolet rays is lowered, and the resolution is deteriorated. Further, the maximum surface roughness Rt of the coating layer surface is in the range of 20 nm or more and less than 200 nm, preferably in the range of 20 to 150 nm. When the maximum surface roughness is 200 nm or more, the dent generated on the resist surface becomes large, and when the resist is removed by the acid edging process, if the dent part exists on the line edge, the edging process degree is affected and a part of the line is affected. There is a problem of missing. On the other hand, when the surface roughness Ra is less than 2 nm and the maximum surface roughness Rt is less than 20 nm, scratches can be seen on the film surface in the process proper, particularly in the film forming process, and the scratches are coated on the surface. A high resolution DFR with a thin resist thickness has a large influence on the resolution due to defects on the resist surface. Moreover, in order to express 0.2 to 0.6 which is a preferable range of the coefficient of friction on the film coating surface, the roll is formed synergistically with the lubricant in the coating layer to synergistically reduce the coefficient of friction and roll. Gives air escape when wrapping into a shape, and improves roll formation such as minute irregularities on the roll surface, unevenness of the roll end face, and wrinkles.

  As a method for imparting an appropriate roughness to the polyester film surface of the present invention, a method of blending fine particles in the film is common. Examples of the contained particles include inorganic particles such as calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide, crosslinked polymer particles, Shu Examples thereof include organic particles such as calcium acid, and precipitated particles formed during polyester polymerization. Among these particles, alumina particles, crosslinked polymer particles, or silica particles are preferably used in order to obtain particularly high transparency and scratch resistance. Since these particles have favorable characteristics in terms of affinity with polyester and refractive index, it is possible to prevent scratches and improve slipperiness without increasing the haze value of the film. One kind of particles may be contained in the surface layer, or two or more kinds may be blended simultaneously. You may use simultaneously the same kind of particle | grains from which a particle size differs. The average particle diameter of such particles is usually 0.01 to 1.0 μm, preferably 0.02 to 0.6 μm. If the average particle size exceeds 1.0 μm, excessively large protrusions will be formed on the film surface, resulting in problems such as insufficient adhesion to the surface of the circuit printed glass and the occurrence of defects. Is likely to fall off from the film surface, which is a cause of deterioration of wear resistance. On the other hand, if the average particle size is less than 0.01 μm, the formation of protrusions is insufficient, so that the slipperiness of the film is insufficient, or the generation of scratches may be observed in the film forming process or resist coating process.

  The haze of the polyester film for dry film resist of the present invention is preferably 1% or less, more preferably 0.6% or less in terms of a film thickness of 16 μm. The light transmittance at 350 nm is preferably 80% or more, more preferably 83% or more. If the haze exceeds 1% and the light transmittance at a wavelength of 350 nm is less than 80%, high-resolution DFR is not sufficiently exposed to ultraviolet rays, leading to circuit defects or reduced resolution. Tend to be.

In the present invention, the term “antistatic property” means, for example, that the specific resistance of the surface is 1.0 × 10 ¹³ Ω / □ or less, preferably 1.0 × 10 ^{7 to} 1.0 × 10 ¹¹ Ω. The range of / □ is good. If the value of the surface resistivity exceeds 1.0 × 10 ¹³ Ω / □, it becomes difficult to control the peeling charge. In the case of the support film for DFR requiring high resolution of the present invention, the surface roughness is small and the film is flat, and if the applied antistatic property is not imparted, the charge is intense, particularly in the case of spark discharge due to peeling charging. Risk of ignition to resist solvent. Further, resist coating defects and foreign matter defects after UV exposure are caused by adhesion of dust and dust due to charging in the polyester film forming process and resist coating process. In particular, even a small amount of small foreign matter may cause a circuit defect in a DFR that requires high resolution.

  The component constituting the layer having antistatic properties can be appropriately selected from a polymer having an arbitrary antistatic property such as an antistatic resin or a conductive resin. Examples of the antistatic agent include a cationic antistatic agent having a cationic functional group such as a quaternary ammonium salt, a pyridinium salt, and a primary to tertiary amino group, a sulfonate group, a sulfate ester base, and a phosphate ester. Anionic antistatic agents having anionic functional groups such as bases and phosphonic acid groups, amphoteric antistatic agents such as amino acids and aminosulfate esters, nonionic functional groups such as polyols, polyglycerols, and polyethylene glycols And various polymer type antistatic agents such as an antistatic agent having a tertiary amino group and a quaternary ammonium group, and monomers and oligomers that can be polymerized by ionizing radiation, such as N, N- Polymerizable antistatic agents such as dialkylaminoalkyl (meth) acrylate monomers and their quaternary compounds, and polyaniline Emissions, polypyrrole, conductive polymers such as polythiophene can be used. Among these, a polymer type antistatic agent having a quaternary ammonium salt type cationic functional group is preferable.

  In the present invention, it is preferable to mix wax and fine particles in the coating layer in order to impart slipperiness simultaneously with the antistatic agent. Examples of the wax include natural waxes such as plant waxes, animal waxes, mineral waxes and petroleum waxes, and synthetic waxes such as synthetic hydrocarbons, modified waxes and hydrogenated waxes. Of these, polyolefin compounds are preferred. Specifically, for example, a compound having, as a basic skeleton, a compound such as a polymer of an unsaturated hydrocarbon such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, or a polyolefin compound composed of a copolymer. Used by dissolving or dispersing, polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymer, ethylene-1-butene copolymer, propylene-1-butene copolymer A polymer etc. can be illustrated. More specifically, it is preferable to use polyolefin having an active hydrogen group at the terminal and having an acid value of 10 to 50, and polyethylene oxide or polypropylene oxide.

  On the other hand, as the fine particles to be used in combination, it is preferable to blend inorganic particles or organic particles having an average particle diameter of 0.01 to 0.2 μm. If the average particle diameter is twice or more the thickness of the coating layer after drying, the particles may fall off from the coating layer. On the other hand, if it is less than 0.01 μm, the effects of easy lubrication and winding improvement tend to be lost. Examples of such fine particles include calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide and other inorganic particles, crosslinked polymer particles, oxalic acid Although organic particles, such as calcium, can be mentioned, among these, in order to obtain particularly high transparency, crosslinked polymer particles or silica particles are preferably used. In the present invention, in order to improve adhesion to the polyester film, thermoplastic resins such as polyesters, polyurethanes, acrylic resins, polyvinyl resins, polyolefins and / or thermosetting acrylics are used as binders. A thermosetting resin such as a resin, a melamine resin, or an epoxy resin may be included.

  It is preferable to apply a coating layer formed by the combined use of such wax and fine particles on the polyester film surface of the base material having the surface roughness of the present invention, so that the friction coefficient of the film is in the range of 0.2 to 0.6. By setting the friction coefficient within this range, it is possible to prevent wrinkles and misalignment of the end face when the polyester film is wound into a roll, and the winding property when the DFR is wound around the roll is also improved. When the friction coefficient is less than 0.2, winding deviation occurs. On the other hand, when it exceeds 0.6, wrinkles and air pockets are generated, which is not preferable.

  The amount ratio of the antistatic agent, wax, fine particles, binder, and crosslinking agent constituting the above-mentioned layer is not particularly specified because the optimum value varies depending on the selected compound, but satisfies the following layer characteristics. A quantitative ratio is preferred. The content of the antistatic agent in the coating layer is usually in the range of 5% by weight or more, preferably 10 to 90% by weight, and when the antistatic agent is a polymer of a compound having an ionic functional group, 15 It is preferable to be in the range of -90% by weight, more preferably 20-90% by weight. If the ratio of the antistatic agent is too small, it will be difficult to achieve a sufficient surface resistivity. Conversely, if the ratio of the antistatic agent is too large, the film adhesion may be insufficient. The blending amount of the wax is 1% by weight or more, preferably in the range of 2 to 10% by weight. If the ratio of the wax is too small, it is difficult to achieve a sufficient slip effect, and if the ratio is too large, the polyester film The adhesiveness with the base material is inhibited, which is not preferable. The ratio of the fine particles used in combination is 1% by weight or more, preferably 2 to 10% by weight. If it is less than 1% by weight, no smoothing and winding improvement effects are observed, and if it is 10% by weight or more, light transmission is inhibited by particle aggregation, which may cause circuit defects.

  The slippery and antistatic layer constituting the film of the present invention is preferably formed by applying an aqueous coating liquid (water-soluble resin or water-dispersible resin using water as a medium), but a small amount of organic solvent. It is also possible to form it by applying an aqueous coating solution containing. Examples of the organic solvent include alcohols such as ethanol, isopropanol, ethylene glycol, and glycerin, ethers such as ethyl cellosolve, t-butyl cellosolve, propylene glycol monomethyl ether, and tetrahydrofuran, ketones such as acetone and methyl ethyl ketone, and esters such as ethyl acetate. And amines such as dimethylethanolamine. These can be used alone or in combination. By appropriately selecting and containing these organic solvents in the aqueous coating liquid as necessary, stability of the coating liquid, applicability, or coating film characteristics can be assisted.

  In the present invention, the solid content concentration of the coating liquid to be used is not particularly limited, but is usually 30% by weight or less, 0.2 to 20% by weight, further 0.5 to 15% by weight, particularly 1 to 10% by weight. The range of is preferable. When the solid content concentration of the coating liquid is reduced, problems such as application repelling uniformity, such as easy application repelling, are likely to occur. On the other hand, when the solid content concentration of the coating liquid exceeds 30% by weight, the viscosity of the coating liquid tends to be high, and the coating appearance may be deteriorated.

  As a method of applying the coating liquid to the base film, for example, reverse roll coater, gravure coater, rod coater, air doctor coater or these as shown in Yuji Harasaki, Tsuji Shoten, 1979, “Coating Method” Other coating equipment can be used. The coating layer according to the present invention can be provided by in-line coating in which coating is performed during film formation, off-line coating in which coating is performed after film formation, or other methods, but is preferably provided by in-line coating.

  In-line coating is a method of coating within the process of manufacturing a polyester film. Specifically, it is a method of coating at any stage from melt-extrusion of polyester to biaxial stretching followed by heat setting and winding. is there. Usually applied to either a substantially amorphous unstretched sheet obtained by melting and quenching, a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction), or a biaxially stretched film before heat setting. To do. In these, the method of extending | stretching to a horizontal direction after apply | coating to a uniaxially stretched film is excellent. According to such a method, since film formation and coating layer drying can be performed simultaneously, there is a merit in manufacturing cost, thin film coating is easy to perform stretching after coating, and heat treatment performed after coating is other than that. Since the high temperature is not achieved by this method, the coat layer and the polyester film are firmly adhered.

  The thickness of the coating layer of the film of the present invention is preferably in the range of 0.02 μm or more and less than 0.1 μm. When the coating thickness is less than 0.02 μm, the uniformity of the coating film is deteriorated, and the antistatic property varies. On the other hand, when the coating layer thickness is 0.1 μm or more, the productivity of the film may be lowered, or peeling may occur at the interface with the polyester film.

  The present invention provides a support for a dry film resist that requires high resolution by providing a coating layer having antistatic property and easy slipperiness on a film having high transparency and extremely flat surface roughness. Prevents accidents caused by electrostatic discharge on the surface and prevents dirt and dust from attracting and adhering to the surface of the base film, preventing pattern irregularities due to adhesion of foreign matter, stabilizing quality, and flatness The industrial value is very large because it is excellent in workability such as workability and slipperiness when winding a simple film into a roll.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples. The method for measuring film properties and the like in the present invention is as follows.

(1) Coating layer thickness Calculated from the consumption of coating solution. The thickness of the coating layer is expressed by the thickness after film stretching and drying.

(2) Antistatic property Using a high resistance measuring instrument made by Hewlett-Packard Japan: HP4339B and measuring electrode: HP16008B, after sufficient humidity adjustment in a measurement atmosphere of 23 ° C. and 50% RH, after 1 minute at an applied voltage of 100V The surface resistivity of the antistatic layer of the base film was measured. From the surface resistivity, the antistatic property was evaluated according to the following criteria.
○: Surface resistivity is less than 1 × 10 ¹¹ Ω / □ △: Surface resistivity is 1 × 10 ¹¹ Ω / □ or more and less than 1 × 10 ¹³ Ω / □ ×: Surface resistivity is 1 × 10 ¹³ Ω / □ or more

(3) Easiness of sliding According to ASTM-D1894, the dynamic friction coefficient was measured by combining the polyester film coated surface and the opposite surface. From the measured friction coefficient, the slipperiness was evaluated according to the following criteria.
○: Dynamic friction coefficient is 0.2 or more and less than 0.5 Δ: Dynamic friction coefficient is 0.5 or more and less than 0.7 ×: Dynamic friction coefficient is 0.7 or more

(4) Film haze According to JIS-7105, the haze of the film was measured with an integrating sphere turbidimeter NDH-20D manufactured by Nippon Denshoku Industries Co., Ltd., and the numerical value was normalized to a film thickness of 16 μm.

(5) Light transmittance at a wavelength of 350 nm The light transmittance at a wavelength of 350 nm was measured using a spectrophotometer MPC-3100 manufactured by Shimadzu Corporation.

(6) Average surface roughness (Ra)
It calculated | required as follows using the Kosaka Laboratory Co., Ltd. surface roughness measuring device (SE-3F). That is, a portion having a reference length L (2.5 mm) is extracted from the film cross-sectional curve in the direction of the center line, the roughness line y = f with the center line of the extracted portion as the x axis and the direction of the vertical magnification as the y axis. When represented by (x), the value given by the following equation is represented by [μm]. The centerline average roughness was expressed as an average value of the centerline average roughness of the extracted portion obtained from 10 cross-sectional curves obtained from the sample film surface. The tip radius of the stylus was 2 μm, the load was 30 mg, and the cutoff value was 0.08 mm.
Ra = (1 / L) ∫ ₀ ^L | f (x) | dx

(7) Maximum height (Rt)
When the extracted portion of the cross-sectional curve obtained at the time of Ra measurement is sandwiched between two straight lines parallel to the average line, the interval between the two straight lines is measured in the direction of the vertical magnification of the cross-sectional curve, and the value is calculated. The value expressed in units of micrometers (μm) was defined as the maximum height Rt of the extracted portion. The maximum height was expressed as an average value of the maximum heights of the extracted portions obtained from 10 cross-sectional curves obtained from the sample film surface.

(8) Scratched film surface The product and the unwound film surface were visually inspected and evaluated according to the following criteria.
○: No scratches are observed in the inspection range. Δ: Thin scratches are observed in a part of the inspection range.
×: Scratches are observed

(9) Photoresist film practical characteristics A photoresist film was produced according to a conventional method. That is, a photoresist layer was provided on the surface opposite to the antistatic and slippery coating surface, and a polyolefin film was laminated thereon as a protective layer. A printed circuit was produced using the obtained photoresist film. That is, the photoresist layer surface of the photoresist film from which the protective layer was peeled was adhered to a copper plate provided on the glass fiber-containing epoxy resin plate. Next, the glass plate on which the circuit was printed was brought into close contact with the photoresist film, and ultraviolet light exposure was performed from the glass plate side. Thereafter, the photoresist film was peeled off, and a series of development operations such as washing and etching were performed to produce a circuit. The circuit thus obtained was observed visually or using a microscope, and the following practical evaluation of the photoresist film was performed according to the quality.
<Resolution>
○: An extremely high resolution and a clear circuit can be obtained. Δ: Phenomena such as slightly inferior sharpness and slightly thick lines are observed, but there is no problem in practical use. Cannot be used for high density circuits
○: No circuit defects are observed. Δ: Circuit defects are rarely observed. ×: Circuit defects are present, which impede practical use.
○: Practical dents are not observed. △: Recesses are observed, but there is no problem for grades that do not require high resolution.

(10) Handling property at the time of DFR manufacture Evaluation was performed regarding the handling property at the time of photoresist film preparation and use.
<Chargeability>
○: Charged polyester film is not charged at all and there is no safety problem. △: Slight charging is recognized, but there is no safety problem for practical use. There are obstacles in safety such as igniting fire, attracting dust and dirt, etc.
○: Since the film has an appropriate roughness and has sufficient slipperiness, the winding characteristics are good. Δ: Although the roughness is slightly insufficient, there is an appropriate slipperiness and there is no practical problem. There is a problem that the resist characteristics are hindered due to turbulence and entrainment air because it is not appropriate and the friction coefficient is not appropriate.

The components of the antistatic layer and the slippery layer used in the following examples and comparative examples are as follows.
[Antistatic layer, easy slip layer component]
Antistatic agent (A1): polydiallyldimethylammonium chloride (average molecular weight: about 30000)
-Wax (B1): Oxidized polyethylene aqueous dispersion (Johnson Polymer 26, John Wax 26)
Particle (C1): Colloidal silica aqueous dispersion having an average particle size of 0.1 μm Water-based resin (D1): Water-based acrylic resin (Nicarbazole Y-8106B, manufactured by Nippon Carbide Industries, Ltd.)
Crosslinking agent (E1): Methoxymethylol melamine (Dainippon Ink Co., Ltd., Becamine J101)

  Pellets of polyethylene terephthalate having an intrinsic viscosity of 0.65 dl / g (containing 100 ppm of crosslinked polymer particles having an average particle size of about 0.3 μm) are dried by hot air crystallization at 180 ° C., and then supplied to an extruder. It was melt-extruded from a T-die into a sheet shape at a temperature, and cast and quenched on a mirror-cooled drum whose temperature was adjusted to 20 ° C. in combination with an electrostatic adhesion method to obtain an unstretched film having a thickness of about 230 μm. Next, this film was stretched 3.7 times in the longitudinal direction at 85 ° C. to obtain a uniaxially stretched film. As an antistatic and easy-sliding layer on this film, a quaternary ammonium salt type cationic polymer antistatic agent: A1, oxidized polyethylene wax: B1, colloidal silica particles: C1, acrylic resin: D1, melamine compound: E1, A coating solution prepared by mixing at a ratio of 20/4/4/52/20 (weight ratio in terms of solid content), diluting with ion-exchanged water to a solid content concentration of 3% by weight, and preparing it on one side of a polyester film. About 5 μm (wet thickness). Next, the film was stretched 3.9 times in the transverse direction in a zone of 110 to 150 ° C. and heat-treated at 230 ° C. to obtain a biaxially stretched polyester film having a thickness of 16 μm and having completed crystal orientation. The coating film was dried by heat treatment after the transverse stretching treatment to obtain a film provided with an antistatic and slippery layer. The film properties of the polyester film obtained by this method are shown in Table 1 below. A photoresist film was provided on the surface opposite to the coating layer, and after drying, a polyethylene film protective film was laminated on the resist surface to prepare a dry film resist (DFR). The characteristics of this DFR are shown in Table 2 below.

  A biaxially stretched polyester film was prepared in the same manner as in Example 1 except that the content of the crosslinked polymer particles in the polyethylene terephthalate and the antistatic and components constituting the slippery layer were changed to the compositions shown in Table 1 below. . The film properties and DFR properties of this film are shown in Table 2 below.

  A biaxially stretched polyester film was prepared in the same manner as in Example 1 except that the content of the crosslinked polymer particles in the polyethylene terephthalate and the antistatic and components constituting the slippery layer were changed to the compositions shown in Table 1 below. . The film properties and DFR properties of this film are shown in Table 2 below.

  Example 1 except that the type and average particle size of the particles contained in the polyethylene terephthalate are changed to those shown in Table 1, and the components constituting the antistatic and easy-slip layer are changed to the compositions shown in Table 1 below. A biaxially stretched polyester film was prepared in the same manner as described above. The film properties and DFR properties of this film are shown in Table 2 below.

Example 1 except that the type and average particle size of the particles contained in the polyethylene terephthalate are changed to those shown in Table 1, and the components constituting the antistatic and easy-slip layer are changed to the compositions shown in Table 1 below. A biaxially stretched polyester film was prepared in the same manner as described above. The film properties and DFR properties of this film are shown in Table 2 below.
(Comparative Example 1)

Example 1 except that the type and average particle size of the particles contained in the polyethylene terephthalate are changed to those shown in Table 1, and the components constituting the antistatic and easy-slip layer are changed to the compositions shown in Table 1 below. A biaxially stretched polyester film was prepared in the same manner as described above. The film properties and DFR properties of this film are shown in Table 2 below.
(Comparative Example 2)

A biaxially stretched polyester film was prepared in the same manner as in Example 1 except that polyethylene terephthalate did not contain particles. Table 2 shows the film characteristics and DFR characteristics of this film.
(Comparative Example 3)

The type and average particle size of the particles contained in the polyethylene terephthalate were changed to those shown in Table 1, and a biaxially stretched polyester film was prepared in the same manner as in Example 1 without applying an antistatic and slippery layer. . The film characteristics and DFR characteristics are shown in Table 2.
(Comparative Examples 4-6)

  Example 1 except that the type and average particle size of the particles contained in the polyethylene terephthalate are changed to those shown in Table 1, and the components constituting the antistatic and easy-slip layer are changed to the compositions shown in Table 1 below. A biaxially stretched polyester film was prepared in the same manner as described above. The film properties and DFR properties of this film are shown in Table 2 below.

  The present invention can be suitably used as a support for a dry film resist that requires high resolution.

Claims (4)

A film having a slippery and antistatic coating layer on at least one surface, and the coating layer surface has an average surface roughness (Ra) of 2 nm or more and less than 10 nm, and a maximum surface roughness (Rt) of 20 nm or more. A polyester film for dry film resist for high resolution, characterized by being less than 200 nm. 2. The polyester for high-resolution dry film resist according to claim 1, wherein the coating layer has a surface resistivity of 1.0 × 10 ¹³ Ω / □ or less and a friction coefficient of 0.2 to 0.6. the film. The polyester film for a high resolution dry film resist according to claim 1 or 2, wherein the coating layer has a thickness of 0.02 µm or more and less than 0.1 µm. The polyester film for a dry film resist for high resolution according to any one of claims 1 to 3, wherein the film haze is 1.0% or less and the light transmittance at a wavelength of 350 nm is 80% or more.