JP2003043691A - Laminated polyester film for photoresist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated polyester film for a photoresist as a base film having excellent winding property of the film and giving excellent resolution when used for a photoresist. SOLUTION: The laminated polyester film for a photoresist is composed of at least two layers and both layers of the top layer (A) and the back layer (B) contain inorganic particles having >=8 Mohs hardness and 0.001 to 0.5 μm average particle size. The proportion of the inorganic particles is 0.1 to 10 wt.% with respect to the polyester in each of the top and back layer. The average surface roughness Ra of the top layer (A) is >=0.005 μm, while the average surface roughness Ra of the back layer (B) is <=0.05 μm. The thickness of the layers shows the relation of (A)<(B). The haze of the film is <=2.0%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester film for photoresists, and more specifically, it has excellent winding properties as a base film, excellent resolution when used in photoresist applications, and can prevent image defects from occurring. The present invention relates to a laminated polyester film for resist.

[0002]

2. Description of the Related Art Photoresists, particularly dry film photoresists, are generally prepared by laminating a photosensitive resin composition on one side of a light-transmissive base film, on which a cover film made of polyethylene or the like is provided. I am using a laminated body. In the photoresist process, the cover film is first removed from the laminate, and the exposed surface of the photosensitive resin composition is attached to an object such as a substrate for producing a printed wiring board. In this state, a negative film is brought into close contact with the base film, and an actinic ray such as ultraviolet rays is irradiated from the side of the negative film so that the base film is transmitted, and the photosensitive resin composition is exposed in a predetermined pattern.
After the exposure, the negative film is removed and the base film is peeled off. By removing the uncured unexposed portion from the remaining photosensitive resin composition with a solvent or the like, a target pattern is formed on the substrate.

In recent years, circuits formed in the photoresist process have become extremely complicated, and the lines have become narrower and the intervals between them have become narrower, and it has become necessary to have high reproducibility of image formation and high resolution. . Therefore, high quality has come to be required for the base film as well. That is, high transparency and low film haze have become increasingly necessary. In the photoresist film, when exposing the photoresist layer, light will pass through the support layer. Therefore, if the transparency of the support is low, problems such as insufficient exposure of the photoresist layer and deterioration of resolution due to light scattering may occur.

The base film for photoresist must also have an appropriate slip property. That is, in order to improve the handleability when the photoresist film is formed by forming a photoresist layer on the film, or to improve the handleability of the photoresist film itself, appropriate slipperiness is required. .

Usually, in order to satisfy the above-mentioned transparency and slipperiness, a method in which specific particles are contained in the film is used. For example, Japanese Unexamined Patent Publication No. 7-333853 describes that a polyester film containing specific particles is laminated to regulate surface roughness and transparency within appropriate ranges.

[0006]

However, Japanese Patent Laid-Open No. 7-3
In the method of Japanese Patent No. 33853, the slipperiness of the film is insufficient, wrinkles are generated during the processing of the photoresist film, and the processing speed cannot be increased, or the particles contained in the film are shaded at the time of exposure to cause defects in the pattern. There was a problem such as going out.

The present invention is intended to solve such problems, and more specifically, it is a base film which is excellent in film winding property and gives excellent resolution when used for photoresist applications. An object of the present invention is to provide a laminated polyester film for photoresist.

[0008]

As a result of intensive studies in view of the above problems, the present inventor has found that a film having a specific constitution has excellent characteristics, and has completed the present invention.

That is, the gist of the present invention is at least 2.
It is a polyester film composed of more than one layer and has a surface layer (A
Both the layer) and the back layer (layer B) contain inorganic particles having a Mohs hardness of 8 or more and an average particle size of 0.001 to 0.5 μm, and the content of the inorganic particles is not limited to the surface layer and 0.1 to 10% by weight based on the polyester of the back layer, and the average roughness Ra of the surface (A layer) surface is 0.005 μm.
As described above, the average roughness Ra of the surface of the back layer (layer B) is 0.05 μm.
The laminated polyester film for photoresist is characterized in that the thickness is A layer <B layer and the film haze is 2.0% or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The polyester used in the present invention is a polyester having a dibasic acid and a glycol as constituent components, and as the aromatic dibasic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ether. Dicarboxylic acid, diphenoxyethanedicarboxylic acid, cyclohexanedicarboxylic acid, diphenylketone dicarboxylic acid, phenylindanedicarboxylic acid, sodium sulfoisophthalic acid, dibromoterephthalic acid and the like can be used. As the alicyclic dibasic acid, cyclohexanedicarboxylic acid, decalindicarboxylic acid, hexahydroterephthalic acid or the like can be used. As the aliphatic dibasic acid, oxalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, dimer acid and the like can be used. As the glycol, ethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, diethylene glycol or the like can be used as the aliphatic diol, and naphthalene diol or 2,2-bis (aromatic diol can be used. 4-hydroxydiphenyl) propane, 2,2-bis (4-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, hydroquinone, tetrapromobisphenol A and the like can be used, and as the alicyclic diol, Cyclohexanedimethanol, cyclohexanediol and the like can be used.

Further, within the range in which the polyester is substantially linear, a trifunctional or higher functional compound such as glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, trimesic acid, pyromellitic acid,
You may copolymerize tricarballylic acid, gallic acid, etc.,
Alternatively, a monofunctional compound such as o-benzoylbenzoic acid or naphthoic acid may be added and reacted. Further, a polyether such as polyethylene glycol or polytetramethylene glycol, or an aliphatic polyester typified by polycaprolactone may be copolymerized.

Two or more kinds of polyester may be blended, and within the range that does not impair the effects of the present invention, for example, if 50 mol% or more is polyester, a polyester other than polyester may be copolymerized or blended. Good.

The polyester used in the present invention preferably has a melting point of 240 ° C. or more and 280 ° C. or less from the viewpoint of heat resistance and film forming property.

The intrinsic viscosity of the polyester used in the present invention (measured in orthochlorophenol at 25 ° C.) is 0.4.
0 to 1.20 dl / g is preferable, and more preferably 0.
Those in the range of 50 to 0.85 dl / g are suitable for the present invention.

The polyester used in the present invention contains an antioxidant within a range not impairing the object of the present invention,
Organic additives such as heat stabilizers, lubricants, and ultraviolet absorbers may be added to the extent that they are usually added.

The particles contained in the polyester film of the present invention have a Mohs hardness of 8 or more and an average particle size of 0.0.
The inorganic particles are from 01 to 0.5 μm. In the present invention, the presence of inorganic particles having a Mohs hardness of 8 or more in the front layer and the back layer not only significantly enhances the slipperiness, abrasion resistance and abrasion resistance of the film, but also improves the transparency of the film. Can be made. Here, if the average particle size is larger than 0.5 μm, coarse protrusions are generated due to aggregation, and pattern defects are likely to occur during exposure, which is not preferable. On the other hand, when the average particle diameter is less than 0.001 μm, it is difficult to obtain the effect of improving the slipperiness, which is not preferable. The average particle size of the inorganic particles is preferably 0.005 to 0.3 μm.
m, more preferably 0.005 to 0.1 μm.

The content of the inorganic particles is as follows:
It is 0.1 to 10% by weight, preferably 0.2 to 5% by weight, and more preferably 0.3 to 3% by weight, based on the polyester of each of the layers) and the back layer (B layer). If the content exceeds 10% by weight, the inorganic particles tend to agglomerate and cause coarse projections, and the strength of the film decreases, which is not preferable. On the other hand, if the content is less than 0.1% by weight, effects such as slipperiness are insufficient, which is not preferable.

Specific examples of the inorganic particles having a Mohs hardness of 8 or more include alumina, silicon carbide, vanadium carbide, titanium carbide, boron carbide, tungsten boride, boron nitride and the like. Of these, industrially easily available alumina or silicon carbide, especially alumina, is preferably used. Two or more kinds of inorganic particles having a Mohs hardness of 8 or more may be used in combination, if necessary.

Examples of alumina include alumina obtained by a thermal decomposition method. The alumina is usually produced by flame hydrolysis as an anhydrous aluminum chloride raw material, and its average particle size is usually 0.01
Is about 0.1 μm.

Further, in the present invention, alumina particles obtained by a hydrolysis method of alkoxide can also be preferably used. The alumina is usually Al (OC2 H7) ₂ or Al.
It is produced using (OC4 H9) 2 as a starting material, and can be obtained as fine particles of 0.5 μm or less by appropriately selecting the hydrolysis conditions. In this case, an acid is added to the synthesized slurry to obtain a transparent sol, which is then gelled, and then heated to 500 ° C. or higher,
A method of using a sintered body of alumina can also be adopted.

In the present invention, alumina fine powder obtained by adding methyl acetate or ethyl acetate to a sodium aluminate solution under stirring to obtain AlOOH and then heating this may be used. In any case, in the present invention, the average particle size is 0.01 to 0.1 μm.
Alumina is particularly preferably used.

The type of alumina used as the inorganic particles in the present invention is preferably at least one type of particles selected from the group consisting of γ-alumina, δ-alumina and θ-alumina, or a mixture thereof. .

In the present invention, it is preferable to use the above alumina particles by completely dispersing them to the primary particles, but the secondary particles may be used as they are as long as the surface condition of the film is not adversely affected. Good. However, also in this case, the apparent average particle size needs to be 0.001 to 0.5 μm, and the average particle size of 0.01 to 0.1 μm is preferably used. When the alumina is agglomerated particles, a part of the alumina, for example, less than 30% by weight of Si, Ti,
It may be substituted with an oxide such as Fe, Na or K.

In the present invention, the surface layer (A layer) and the back layer (B layer) have a Mohs hardness of 8 or more and an average particle size of 0.0.
By including a specific amount of the inorganic particles of 01 to 0.5 μm, the transparency of the film is improved, and the slipperiness, scratch resistance, and abrasion resistance of the film surface are significantly improved.

Here, in order to further improve the running property, winding property, and workability of the film, both the surface layer (A layer) and the back layer (B layer) have a Mohs hardness of less than 8 and an average particle size of 0. It is preferable to use inactive particles having a diameter of 2 to 3 μm in combination. The average particle size of the inert particles is more preferably 0.5 to 2 μm.

Specific examples of the inert particles having a Mohs hardness of less than 8 include kaolin, talc, carbon, molybdenum sulfide, gypsum, rock salt, calcium carbonate, silicon oxide, barium sulfate, lithium fluoride and fluorinated. Examples thereof include inorganic particles such as calcium, zeolite, and calcium phosphate, and particles made of a crosslinked polymer. Among these, calcium carbonate, silicon oxide, barium sulfate, zeolite, calcium phosphate, and a crosslinked polymer (for example, crosslinked polystyrene) are preferably used from the viewpoint of dispersibility in polyester, and a crosslinked polymer is particularly preferably used.

The cross-linking polymer preferably used in the present invention includes, for example, one or more monovinyl compounds (a) having only one aliphatic unsaturated bond in the molecule,
It can be obtained by copolymerizing, as a cross-linking agent, one or more compounds (b) having two or more aliphatic unsaturated bonds in the molecule in the presence of a specific initiator by an emulsion polymerization method. The emulsion polymerization method here refers to an emulsion polymerization method in a broad sense that also includes the concept of seed emulsion polymerization and the like. Examples of the monovinyl compound (a) include acrylic acid, methacrylic acid and their alkyl or glycidyl esters, maleic anhydride and its alkyl derivatives, vinyl glycidyl ether, vinyl acetate, styrene, and alkyl-substituted styrene. Examples of the compound (b) include divinylbenzene, divinyl sulfone, ethylene glycol dimethacrylate, 1,4 butanediol diacrylate and the like. The compounds (a) and (b) are copolymerized by using one kind or more, but a compound containing a nitrogen atom or ethylene may be copolymerized.
Here, as the polymerization initiator, for example, potassium persulfate,
Examples thereof include, but are not limited to, water-soluble polymerization initiators such as potassium persulfate-sodium thiosulfate and hydrogen peroxide.

The crosslinked polymer may form agglomerated particles depending on the combination of the above-mentioned compounds or the conditions for synthesizing the particles. Therefore, it is preferable to use a dispersion stabilizer in order to maintain the dispersibility of the particles. . Examples of dispersion stabilizers include fatty acid salts, alkyl sulfate ester salts, alkylbenzene sulfonates, alkylsulfosuccinates, alkylnaphthalene sulfonates, alkyldiphenyl ether disulfonates, alkyl phosphates, polyoxyethylene alkyl or alkyl allyl sulfates. Anionic surfactants such as ester salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene derivatives, polyoxyethylene oxypropylene block copolymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxy Nonionic surfactants such as ethylene sorbitol fatty acid ester and glycerin fatty acid ester, and positive ions such as alkylamine salts and quaternary ammonium salts. Surfactants and alkyl betaines, can be used cationic surfactants such as amine oxides. Among these, anionic surfactants typified by alkyl diphenyl ether disulfonate are preferably used.

The cross-linked polymer used as the inert particles has a good heat resistance such that the weight loss after heating for 2 hours at 300 ° C. in nitrogen gas is 20% by weight or less, more preferably 10% by weight or less. preferable. If this value exceeds 20% by weight, the particles tend to fuse together to form agglomerated particles.

A preferred embodiment of the production of crosslinked polymer inactive particles is as follows. That is, after dissolving a predetermined amount of a water-soluble polymerization initiator such as potassium persulfate and a dispersion stabilizer such as alkyldiphenyl ether disulfonate in an aqueous medium, a predetermined amount of the above-mentioned compounds (a) and (b) Add the mixed solution. Thereafter, the temperature is not lower than the decomposition start temperature of the polymerization initiator, preferably 30 to 90 ° C. under stirring for 3
By carrying out the reaction for about 10 hours, inert particles composed of a crosslinked polymer can be obtained. In this case, the inert particles are obtained as a uniformly dispersed water slurry.

The inert particles having a Mohs hardness of less than 8 are 0.0 or less in both the surface layer (A layer) and the back layer (B layer).
It is preferable to add 05 to 0.5% by weight, and more preferably 0.005 to 0.1% by weight. Here, the addition of inert particles having a Mohs hardness of less than 8 has the effect of improving the slipperiness of the film surface, but at the same time tends to reduce the transparency, so addition of a small amount within the range where there is the effect of slipperiness It is preferable to limit it to.

In the laminated polyester film for photoresist of the present invention, the surface layer (A layer) and the back layer (B layer)
Each contain particles, the layer A is a layer that imparts slipperiness, and the layer B is a layer on which a photosensitive resin composition is laminated when the film of the present invention is used. The film of the present invention preferably has a two-layer structure of A / B,
It may have a three-layer structure of / B or a multi-layer structure having more layers. Here, / represents stacking.

For each of the layers A, B and C, the same or different polyesters may be used, or the same or different inorganic particles may be added. For example, the same kind of raw material may be used and the thickness ratio of the A layer and the B layer may be simply changed. That is,
For example, a method of forming a smaller number of protrusions on the surface of the A layer than the B layer by laminating the A layer having a reduced thickness using the same polyester composition as the raw material on the B layer can also be used.

The thickness of the layer A of the film of the present invention must be smaller than that of the layer B. The thickness of the layer A is preferably 0.05 to 10 μm, more preferably 0.1 to 3 μm.
m, particularly preferably 0.1 to 2 μm. When the thickness of the layer A exceeds 10 μm, the transparency of the film may not be highly satisfied. On the other hand, when the thickness of the A layer is less than 0.05 μm, the particles contained in the A layer are likely to fall off, and the abrasion resistance of the film may be deteriorated. Further, if particles that fall off or abrasion powder are generated and enter between the film and the photoresist layer, the reactivity of the photosensitive resin may be affected.

The thickness of layer B is preferably 1 to
The thickness is 200 μm, more preferably 3 to 100 μm, and particularly preferably 5 to 50 μm.

The film haze of the film of the present invention is 2.
It should be 0% or less. The film haze is preferably 1.5% or less, more preferably 1.1% or less. If the haze exceeds 2.0%, the resolution becomes insufficient, which is not preferable. Therefore, the film haze is 2.
It is necessary to adjust the type of particles, the particle size, the addition amount, the laminated thickness, etc. so that the content is 0% or less.

Average roughness Ra of the surface of the film of the present invention
Is required to be 0.005 μm or more on the surface of layer A,
Preferably 0.01 μm or more, more preferably 0.01
Is about 0.05 μm. The average roughness Ra of the surface of the A layer is 0.
When the thickness is less than 005 μm, the handling property and winding property of the film become insufficient, which is not preferable. On the other hand, if the thickness exceeds 0.05 μm, the resolution may decrease.

The average roughness Ra of the surface of the B layer is 0.0
It is necessary to be 5 μm or less, preferably 0.001 to
0.03 μm, more preferably 0.005-0.02 μm
m. If the average roughness Ra of the surface of the B layer exceeds 0.05 μm, pattern defects occur and the resolution deteriorates, which is not preferable.

Next, a preferable method for producing the film of the present invention will be described.

First, as a method of incorporating the inert particles into the polyester, there is a method of dispersing the inert particles in the form of a slurry in ethylene glycol which is a diol component and polymerizing the ethylene glycol with a predetermined dicarboxylic acid component. It is effective for obtaining a film in a preferred orientation state without stretching breakage. Further, the method of adjusting the melt viscosity of the polyester containing the inert particles, the copolymerization component and the like to keep the crystallization parameter ΔTcg in the range of 40 to 65 ° C. is suitable for photoresist use without stretching breakage. It is effective in obtaining a film.

A slurry of ethylene glycol containing inert particles is heated to 140 to 200 ° C., particularly 180 to 20.
The method of heat treatment at a temperature of 0 ° C. for 30 minutes to 5 hours, particularly 1 to 3 hours is effective for obtaining a film having a preferable orientation state and a surface layer particle concentration ratio without stretching breakage.

As another method for incorporating the inert particles into the polyester, the inert particles are heated in ethylene glycol at a temperature of 140 to 200 ° C., particularly 180 to 200 ° C. for 30 minutes to 5 hours, particularly 1 to 3 hours. After heat treatment, mixed with polyester in the form of a slurry in which the solvent was replaced with water,
A method of kneading using a vent type twin-screw extruder and kneading into polyester is also preferably used.

The method for adjusting the content of the inert particles is not particularly limited, but for example, a high-concentration master is prepared by any of the above-mentioned methods, and the inert particles are substantially contained during the film formation. A method of adjusting the content of particles by diluting with a non-useful polyester is effective and is preferably used.

The following method is effective as a method for laminating the films constituting the surface layer (A layer) and the back layer (B layer). That is, a polyester pellet containing a predetermined amount of inert particles is dried as needed, and then a polyester A constituting the A layer and a polyester B constituting the B layer are formed.
A predetermined amount of (A and B may be the same or different) is supplied to a known extruder for melt lamination, and extruded into a sheet from a slit die at a melting point of polyester or more and a decomposition point or less, and then on a casting roll. It is cooled and solidified to prepare an unstretched film. More specifically, two or three extruders, two or three layer manifolds or confluent blocks are used to laminate polyesters A and B, and the two die
Alternatively, a three-layer sheet is extruded and cooled with a casting roll to produce an unstretched film. In this case, the method of installing a static mixer and a gear pump in the polymer channel of polyester A is effective for obtaining a good quality film that does not stretch and break. Further, the melting temperature of the extruder on the polyester A side is 10 to 40 ° C. from the polyester B side.
A higher value is effective for obtaining a good quality film that does not stretch and break.

This unstretched film is biaxially stretched and biaxially oriented. As a stretching method, a sequential biaxial stretching method or a simultaneous biaxial stretching method can be used. By using the simultaneous biaxial stretching method, the film of the present invention can be produced with high productivity and at low cost. Here, the longitudinal stretching ratio is 3.5 to 6.5, and the transverse stretching ratio is 3.0 to 5.
A range of 0 times is preferable.

Further, a sequential biaxial stretching method in which stretching is first carried out in the longitudinal (longitudinal) direction and then in the transverse (width) direction, the longitudinal stretching is divided into three stages or more, and the total longitudinal stretching ratio is 3. ．
A method of carrying out 5 to 6.5 times is also preferably used. This method is an effective method for obtaining a film having a preferable orientation state and surface layer particle concentration ratio without stretching breakage. At that time, the longitudinal stretching temperature is usually 50 to 130 ° C. in the first step.
However, it is preferable that the second and subsequent stages have higher heights.
Further, the longitudinal stretching speed is preferably in the range of 5,000 to 50,000% / min. On the other hand, as a stretching method in the width direction, a method using a stenter is generally used. Further, the stretching ratio in the width direction is preferably in the range of 3.0 to 5.0 times. The stretching speed in the width direction is preferably 1000 to 20000% / min, and the temperature is preferably 80 to 160 ° C.

Next, this stretched film is heat-treated. In this case, the heat treatment temperature is preferably 170 to 250 ° C,
More preferably, it is 180 to 240 ° C., and the heat treatment time is 0.
A range of 5-60 seconds is preferred.

The film of the present invention is used as a base film for photoresist. The photoresist is not particularly limited as long as it is used as a photoresist, but is preferably used for a high-definition dry photoresist, for example. Further, due to the characteristics of the film of the present invention, it may be used as a film for laminating windows and a film for laminating, which is required to have transparency and slipperiness, other than photoresist applications.

[0049]

EXAMPLES The methods for measuring physical properties and the methods for evaluating effects used in the present invention will be described.

(1) Average particle size of particles: D Polyester is removed from the film by a plasma low temperature ashing method (for example, PR-503 type manufactured by Yamato Scientific Co., Ltd.) to expose the particles. The processing conditions are selected such that polyester is incinerated but particles are not damaged. This is SE
Observe with M (scanning electron microscope), connect the image of the particles (light and shade of light produced by the particles) to an image analyzer (for example, QTM900 made by Cambridge Instruments), change the observation point and the number of particles is 5000 or more. The number average diameter D obtained by the treatment is used as the average particle diameter. D = ΣDi / N Here, Di is the equivalent circle diameter of particles, and N is the number of particles.

(2) Content of Particles A solvent in which the polyester is dissolved but the particles are not dissolved is selected, the particles are centrifuged from the polyester, and the ratio (% by weight) to the total weight of the particles is defined as the particle content.

(3) Thickness of layers A and B in the laminated film Using a secondary ion mass spectrometer (SIMS), the element M + derived from the highest concentration of particles in the film
Ratio of carbon element C + of polyester and polyester (M + / C +)
Is set as the particle concentration and the analysis is performed in the depth (thickness) direction from the surface of the A layer. The particle concentration is low near the surface of the layer A and increases as it moves away from the surface. In the case of the film of the present invention, the particle concentration once reaching the maximum value at the depth [I] starts to decrease again. Based on this concentration distribution curve, the depth [II] (where II
> I) is the thickness of the A layer. The thickness of the B layer was a value obtained by subtracting [II] from the total thickness of the film of the present invention. The thickness was measured at three arbitrary points and the average value was used. If the most abundant particles in the film are particles of organic polymer, it is difficult to measure with SIMS, so XPS (X
Line photoelectron spectroscopy), the depth profile of the particle concentration was measured, and the laminated thickness was determined by the same method as above.

(4) Film haze The film haze was measured according to JIS-K-7105.

(5) Average surface roughness: Ra was measured using a high precision thin film step gauge ET-10 manufactured by Kosaka Seisakusho. The conditions are a tip radius of the stylus of 0.5 μm, a needle pressure of 5 mg, a measurement length of 1 mm, and a cutoff of 0.08 mm. The definition of Ra is given, for example, in Jiro Nara "Surface Roughness Measuring Method" (General Technology Center, 1983).

(6) Rollability A film was slit into a width of 1000 mm and a length of 4000 m, wound on a paper core having a length of 1200 mm, an inner diameter of 6 inches and a wall thickness of 12 mm, and the wound state was observed and judged according to the following criteria. . ○ was passed. Wound with no defects such as wrinkles: ○ Defects such as wrinkles: × (7) A known photosensitive resin was applied to a resolution film to a thickness of 45 μm, and then the film was laminated on a copper-clad laminate. Later, a negative film for resolution evaluation (STOUFFER GRAPH
IC ARTS EQUIPMENT, 21STE
P, SENSITIVITY GUIDE, # T211
5) was provided and exposed to remove the film. Then 30
The unexposed part is removed by spraying with a 1.0 wt% sodium carbonate aqueous solution at a spraying pressure of 1.0 kg / cm ² for 60 seconds, and the number of step tablets of the photocured film on the copper-clad laminate is measured. Then, it was judged according to the following criteria. Here, the larger the number of steps, the better the resolution. ◯ was judged to be acceptable. Number of stages 8.0 or more: resolution ○ Number of stages less than 8.0: resolution × (8) Intrinsic viscosity: [η] The value calculated from the following formula was used from the solution viscosity measured in orthochlorophenol at 25 ° C. ηsp / C = [η] + K [η] 2 · C where ηsp = (solution viscosity / solvent viscosity) -1 C: weight of dissolved polymer per 100 ml of solvent (g / 1
00 ml) K: Huggins constant (0.343) The solution viscosity and the solvent viscosity were measured with an Ostwald viscometer.

(9) Orthocresol / chloroform (weight ratio 7 /
3) was dissolved at 90 to 100 ° C., and the potential difference was measured with an alkali.

Next, the present invention will be described based on examples, but the present invention is not limited thereto.

Example 1 As polyester A used for the surface layer (A layer), 0.7% by weight of δ-alumina particles (Mohs hardness 9) having an average particle size of 0.05 μm and calcium carbonate having an average particle size of 1.1 μm were used. Polyethylene terephthalate containing 0.04% by weight of particles (Mohs hardness 3) (intrinsic viscosity 0.63 dl / g, carboxyl end group amount 38 equivalents / ton), average particle size as polyester B used for back layer (B layer) Δ of 0.05 μm
-Polyethylene terephthalate containing 0.1% by weight of alumina particles (Mohs hardness 9) (intrinsic viscosity 0.64 dl
/ G, the amount of carboxyl end groups is 38 equivalents / ton), respectively, are vacuum-dried to a water content of 20 ppm, then supplied to different extruders and melted at 280 ° C. so that two layers of A layer / B layer are formed. After merging the polymer with the above, it was extruded into a sheet form from a T-shaped die and cooled and solidified on a cooling drum having a surface temperature of 25 ° C. by an electrostatic adhesion method. The laminated unstretched film thus obtained was heated to 90 ° C., stretched in the longitudinal direction at 105 ° C. by 3.6 times, and then heated at 108 ° C. in the width direction by 4.0 times. . This film was introduced into hot air at 220 ° C. and subjected to tension heat treatment for 3 seconds, and then 5% of the original film width in the lateral direction within the same atmospheric temperature.
By relaxing and cooling, a biaxially stretched laminated polyester film was obtained. The thickness of this film was 16 μm, that is, the A layer was 2.0 μm and the B layer was 14 μm.

Example 2 As polyester B, δ-alumina particles having an average particle size of 0.05 μm (Mohs hardness 9) was 0.1% by weight, and calcium carbonate particles having an average particle size of 1.1 μm (Mohs hardness 3) was 0.1%. Polyethylene terephthalate containing 005% by weight (intrinsic viscosity 0.64 dl / g, carboxyl end group amount 3
A biaxially stretched laminated polyester film was produced in the same manner as in Example 1 except that 8 equivalents / ton) was used, and finally a film having a total thickness of 16 μm, in which the A layer was 1.0 μm and the B layer was 15 μm, was obtained. .

Example 3 As polyester A, 0.7% by weight of δ-alumina particles (Mohs hardness 9) having an average particle diameter of 0.05 μm and silicon dioxide particles (Mohs hardness 7) having an average particle diameter of 1.2 μm were used.
Polyethylene terephthalate containing 02% by weight (intrinsic viscosity 0.63 dl / g, carboxyl end group amount 38 equivalent / ton), polyester B having an average particle diameter of 0.05 μm
0.1% by weight of δ-alumina particles (Mohs hardness 9) of
Except for using polyethylene terephthalate containing silicon dioxide particles having an average particle diameter of 1.2 μm (Mohs hardness 7) in an amount of 0.005% by weight (intrinsic viscosity 0.64 dl / g, carboxyl end group amount 38 equivalent / ton). A biaxially stretched polyester film was produced in the same manner as in Example 1,
Finally, the A layer is 1.0 μm and the B layer is 15 μm, for a total of 16
A film of μm was obtained.

Example 4 After obtaining an unstretched film laminated by using the same polyester as in Example 2, the film was heated at 90 ° C. for 2 seconds using a simultaneous biaxial stretching machine, and then stretched at 106 ° C. Direction 3.
After the film was simultaneously biaxially stretched 6 times and 3.8 times in the transverse direction, this film was subjected to tension heat treatment at 220 ° C. for 3 seconds, and then 5% of the original film width in the transverse direction in the same atmosphere temperature in the longitudinal direction. 1% to relax and cool. Finally, a film having a total thickness of 16 μm, in which the A layer was 1.0 μm and the B layer was 15 μm, was obtained.

The films obtained in Examples 1 to 4 were evaluated by the above-mentioned film evaluation method, and as a result, they were excellent in winding property and resolution. The results are summarized in Table 1.

Comparative Example 1 0.5% by weight of δ-alumina particles having an average particle size of 0.05 μm (Mohs hardness 9) and 0.04% by weight of calcium carbonate particles having an average particle size of 1.1 μm (Mohs hardness 3). Polyethylene terephthalate contained (intrinsic viscosity 0.63 dl /
g, the amount of carboxyl end groups is 38 equivalents / ton), and melted at 280 ° C. to obtain an unstretched film consisting of a single layer. Then, stretching and heat treatment are performed in the same manner as in Example 1 to obtain 16 μm.
I got a film. The evaluation results are shown in Table 1. The film of this comparative example having a single layer was inferior in resolution.

Comparative Example 2 A film was produced in the same manner as in Example 2, and finally the A layer was 1
A film having a total thickness of 2 μm and a layer B of 4 μm and a total thickness of 16 μm was obtained. The evaluation results are shown in Table 1. The film of this comparative example, in which the thickness of the A layer was large and the haze was large, was inferior in resolution.

Comparative Example 3 As polyester A, 0.7% by weight of δ-alumina particles having an average particle size of 0.05 μm (Mohs hardness 9) and calcium carbonate particles having an average particle size of 1.1 μm (Mohs hardness 3) of 0. Polyethylene terephthalate containing 6% by weight (intrinsic viscosity 0.64 dl / g, carboxyl end group amount 3
The film was produced in the same manner as in Example 2 except that 8 equivalents / ton) was used, and finally a film having a total thickness of 16 μm was obtained in which the A layer was 1.0 μm and the B layer was 15 μm. The evaluation results are shown in Table 1. The film of this comparative example having a haze outside the range of the present invention was inferior in resolution.

Comparative Example 4 Polyethylene terephthalate (intrinsic viscosity 0.64d) containing 0.005% by weight of calcium carbonate particles (Mohs hardness 3) having an average particle size of 1.1 μm as polyester B
A film was produced in the same manner as in Example 1 except that 1 / g, the amount of carboxyl end groups was 38 equivalents / ton) was used, and finally a film having a total thickness of 16 μm was obtained, in which the A layer was 1.0 μm and the B layer was 15 μm. The evaluation results are shown in Table 1. The film of this comparative example, which did not contain inorganic particles in the B layer, had poor winding property and poor slipperiness, and thus was inferior in processability.

[0067]

[Table 1]

[0068]

According to the present invention, it is possible to provide a laminated polyester film for photoresist which is a base film which is excellent in film winding property and gives excellent resolution when used in photoresist applications.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H025 AA00 AA02 AB11 AB15 AC01                       AD01 BC13 BC42 DA20                 4F100 AA19A AA19B AK41A AK41B                       AK42 BA02 CA23A CA23B                       DD01A DD01B DD07A DD07B                       DE01A DE01B EH172 EJ38A                       EJ38B EJ382 EJ422 JK12A                       JK12B YY00A YY00B

Claims (5)

[Claims] 1. A polyester film comprising at least two layers, wherein both the surface layer (A layer) and the back layer (B layer) have a Mohs hardness of 8 or more and an average particle size of 0.1.
001 to 0.5 μm of inorganic particles, the content of the inorganic particles is 0.1 to 10% by weight with respect to the polyester of the surface layer and the back layer, and the average roughness of the surface (A layer) surface. Ra is 0.005 μm or more, the average roughness Ra of the surface of the back layer (B layer) is 0.05 μm or less, the thickness constitution is A layer <B layer, and the film haze is 2.0% or less. A laminated polyester film for photoresist, which is characterized by: 2. The laminated polyester film for photoresist according to claim 1, wherein the polyester film has a two-layer structure of a surface layer (A layer) and a back layer (B layer). 3. The photoresist according to claim 1, which contains at least one kind of particles selected from the group of γ-alumina, δ-alumina and θ-alumina as inorganic particles. Laminated polyester film. 4. In addition to the inorganic particles, both the surface layer (A layer) and the back layer (B layer) contain inert particles having a Mohs hardness of less than 8 and an average particle size of 0.2 to 3 μm. A laminated polyester film for photoresist according to any one of claims 1 to 3. 5. A polyester film produced by simultaneous biaxial stretching.
4. A laminated polyester film for photoresist according to any one of 4 above.