JP3212892B2 - Photosensitive laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive laminate, and more particularly, to a printed wiring board, a flat printed board, etc. having a photoresist photosensitive layer, having excellent handleability, having excellent resolution and eliminating circuit defects. And a photosensitive laminate useful for the production of

[0002]

2. Description of the Related Art In recent years, a photosensitive laminate having a photoresist photosensitive layer has been used for manufacturing a printed wiring board, a flat plate printing board, and the like. The photosensitive laminate usually comprises a support, a photoresist photosensitive layer, and a protective layer,
As this support layer, a polyethylene terephthalate film, a polyolefin film, or the like is used. Particularly, a polyester film having excellent mechanical, chemical and optical properties is used.

In the case of a printed wiring board, for example, a circuit is formed by first peeling off a protective layer of a laminated body, and bringing an exposed photoresist layer into close contact with a conductive substrate adhered to a substrate. The negative or positive image of the original pattern is brought into close contact with the support side, and the photosensitive resin of the photoresist photosensitive layer is exposed and reacted by irradiating light, and then the unreacted portions of the photoresist photosensitive layer are removed with a solvent or the like. I do. Further etching with an acid or the like removes the conductive base material that is exposed by removing the photoresist photosensitive layer, and the conductive base material that is not removed by the reaction of the photosensitive resin and the solvent remains as it is. Will be. Thereafter, if the remaining photoresist photosensitive layer is removed by an appropriate means, a conductive base material layer is formed as a circuit on the substrate.

[0004] Therefore, the polyester film used as the support is required to have high transparency and low film haze. When exposing the photoresist photosensitive layer, light passes through the support, and if the transparency of the support is low, the photoresist photosensitive layer may not be sufficiently exposed or light may be scattered, resulting in lower resolution. Problems such as deterioration occur.

On the other hand, in order to improve the handleability when manufacturing the photosensitive laminate and the handleability of the photosensitive laminate itself, it is necessary that the polyester film of the support has an appropriate sliding property. Required.

Conventionally, in order to satisfy such characteristics,
A method has been used in which fine particles are contained in a polyester film to form fine projections on the film surface.

For example, Japanese Patent Application Laid-Open No. 7-333853 discloses that at least one outermost layer has an average particle size of 0.01 to 3.
0 μm fine particles (spherical or amorphous silica particles, spherical crosslinked polymer particles, etc.), and Ra of the outermost layer is 0.00
Biaxially oriented laminated polyester films for photoresists having a thickness of 5 μm or more, Rt of less than 1.5 μm, and a film haze of 1.5% or less have been proposed.

However, in the case of a polyester film, if fine particles are added to such an extent that sufficient handleability can be obtained, transparency is reduced due to generation of voids during orientation, and the film cannot be used as a photoresist film. There is a problem. In addition, the above-mentioned laminated polyester film has a problem that its manufacturing cost is increased.

Further, if the adhesion between the polyester film as a support and the photoresist photosensitive layer is too strong, there is a problem that the photoresist photosensitive layer is damaged when the support is peeled off after exposure.

[0010]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the prior art, and simultaneously satisfies the handleability in manufacturing a photosensitive laminate, and the handleability and resolution of the photosensitive laminate itself. It is an object of the present invention to provide a photosensitive laminate that performs

[0011]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by including a specific porous silica in a polyester film used as a support of a photosensitive layer, the exposure of the present invention is improved. The inventors have found that the light transmittance at the time and the resolution of the obtained image can be greatly improved, and have completed the present invention.

That is, the present invention relates to a photosensitive laminate in which a photoresist photosensitive layer is laminated on a film support having a thickness of 10 μm or more, wherein the film support has 1) an average particle size of 0.01 to 0.1 μm. Although it contains porous silica particles which are aggregates of primary particles, the number of coarse aggregated particles having a size of 50 μm or more in the film is 10 /
m ² or less, 2) a center line average roughness of the film (Ra) of the surface is 0.01
and 3) a biaxially stretched polyester film having a film haze of 5% or less at a thickness of 25 μm.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The support of the photosensitive laminate in the present invention is a biaxially stretched polyester film, and the polyester used for the support is an aromatic dicarboxylic acid as a main acid component and an aliphatic glycol as a main glycol component. It is a thermoplastic polyester. Such polyesters are substantially linear and have film-forming properties, especially by melt-forming. Examples of the aromatic dicarboxylic acid component include terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, diphenylethanedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylketonedicarboxylic acid, and anthracenedicarboxylic acid. And the like. Examples of the aliphatic glycol include polymethylene glycol having 2 to 10 carbon atoms such as ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, and decamethylene glycol, and 1,4-cyclohexanedimethanol. Such as aliphatic diols.

In the present invention, as the polyester, alkylene terephthalate and / or alkylene-
Those containing 2,6-naphthalate as a main component are preferably used.

Among such polyesters, terephthalic acid and / or 2,6-naphthalenedicarboxylic acid account for at least 80 mol% of all dicarboxylic acid components, including polyethylene terephthalate and polyethylene-2,6-naphthalate, and all glycol components. Is preferably a copolymer in which 80 mol% or more of ethylene glycol is ethylene glycol. that time,
Up to 20 mol% of the total acid component can be the above-mentioned aromatic dicarboxylic acid component other than terephthalic acid and / or 2,6-naphthalenedicarboxylic acid component, and aliphatic dicarboxylic acids such as adipic acid, sebacic acid and the like. An alicyclic carboxylic acid such as cyclohexane-1,4-dicarboxylic acid; Further, 20 mol% or less of the total glycol component can be the above-mentioned glycol other than ethylene glycol.
Aromatic diols such as resorcinol and 2,2-bis (4-hydroxydiphenyl) propane; aliphatic diols having an aromatic ring such as 1,4-dihydroxymethylbenzene; polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like Polyalkylene glycol (polyoxyalkylene glycol)
And so on.

The polyester in the present invention includes:
Aromatic oxyacids such as, for example, hydroxybenzoic acid;
Also included are those which copolymerize or combine a component derived from an oxycarboxylic acid such as an aliphatic oxyacid such as hydroxycaproic acid at 20 mol% or less based on the total amount of the dicarboxylic acid component and the oxycarboxylic acid component.

Further, the polyester in the present invention may be used in an amount in a range substantially linear, for example, 2 mol% based on the total acid component.
The following amounts also include those obtained by copolymerizing trifunctional or higher functional polycarboxylic acids or polyhydroxy compounds such as trimellitic acid and pentaerythritol.

The above-mentioned polyesters are known per se and can be produced by a method known per se.
As the above polyester, the intrinsic viscosity measured at 35 ° C. as a solution in o-chlorophenol is about 0.4 to
0.9 is preferred.

The polyester film in the present invention needs to contain porous silica particles which are aggregated particles. If conventional spherical or amorphous silica particles are contained, voids are generated at the time of orientation, and sufficient transparency and light transmittance that can be used as a photosensitive laminate cannot be obtained.

The average particle size of the primary particles constituting the porous silica particles must be in the range of 0.01 to 0.1 μm. If the average particle size of the primary particles is less than 0.01 μm, ultrafine particles are generated by crushing at the slurry stage, which is not preferable because it forms aggregates. On the other hand, when the average particle size of the primary particles exceeds 0.1 μm, the porosity of the particles is lost, and as a result, the affinity with the polyester is lost and voids are easily generated, which is not preferable.

Further, the porous silica particles have a pore volume of 0.5 to 2.0 ml / g, preferably 0.6 to 1.8.
It is preferably in the range of ml / g. When the pore volume is less than 0.5 ml / g, the porosity of the particles is lost, voids are easily generated, and the transparency and light transmittance are lowered. On the other hand, if the pore volume is larger than 2.0 ml / g, crushing and agglomeration are likely to occur, and it is difficult to adjust the particle size.

The average particle size of the porous silica particles is 0.1
５5 μm, preferably 0.3-3 μm. When the average particle size is less than 0.1 μm, the film has insufficient slipperiness. On the other hand, when the average particle size exceeds 5 μm, the surface of the film becomes too rough, and the adhesion to the glass plate on which the circuit is printed is insufficient. This is not preferable because defects such as a decrease in resolution occur.

The amount of the porous silica particles added is 0.01
0.1 to 0.1% by weight, preferably 0.02 to 0.06% by weight
It is. If the addition amount is less than 0.01% by weight, the slipperiness of the film is insufficient, while if it exceeds 0.1% by weight, transparency and light transmittance are undesirably reduced.

The polyester film in the present invention is used as a biaxially stretched polyester film, and the number of coarse aggregated particles having a size of 50 μm or more in the film is 10 /.
m ² or less, preferably 5 / m ² or less, more preferably 3 / m ² or less. If the number of coarse aggregated particles having a size of 50 μm or more is more than 10 / m ² , defects such as a decrease in resolution occur, which is not suitable. Practically 1
The number of coarse aggregated particles having a size of 00 μm or more is preferably ² / m ² or less.

In order to reduce the number of coarse aggregated particles to 10 particles / m ² or less, an average aperture of 10 to 30 μm made of a stainless steel fine wire having a wire diameter of 15 μm or less is used as a filter during film formation.
It is preferable to filter the molten polymer by using a nonwoven fabric type filter having a m, preferably 15 to 25 μm. If the opening of the filter exceeds 30 μm, there is no effect of reducing coarse particles in the molten polymer, while the opening is 10 μm.
If less than m, the pressure and pressure rise during filtration will be large,
It is difficult to put the filter into practical use industrially.
When the wire diameter exceeds 15 μm, the average aperture is 10 to 30.
At μm, coarse particles cannot be collected.

When another network structure, sintered metal material, or the like is used as the filter, even if the average opening is equal to or smaller than the above average opening, the coarse aggregated particles of the porous silica particles are supplemented. It is difficult to gather. This is because the stainless steel thin wire that constitutes the nonwoven fabric filter not only captures the coarse particles of porous silica, but also breaks the coarse aggregated particles,
It is thought to have the effect of dispersing.

The porous silica particles are generally used at the time of the reaction for producing the polyester, for example, at any time during the transesterification reaction or polycondensation reaction in the case of transesterification, or in the case of the direct polymerization method. At times, it is added to the reaction system (preferably as a slurry in glycol). In particular, it is preferable to add porous silica particles to the reaction system at the beginning of the polycondensation reaction, for example, until the intrinsic viscosity reaches about 0.3.

The polyester film of the present invention is basically produced by melt-forming the above-mentioned polyester, biaxially stretching and further heat-treating. The method and conditions of each of these steps are known in the art. Method and conditions. To explain in more detail, first,
The polyester is melted, filtered through a filter, extruded into a sheet from a slit die, cooled and solidified by a casting drum to form an unstretched sheet, and the unstretched sheet is stretched at a temperature of 70 to 120 ° C and a stretching ratio of 3 to 3 mm. It can be preferably produced by stretching in the longitudinal and transverse directions by a factor of 5 and then heat-treating at 200 to 250 ° C.

The polyester film thus obtained usually has a surface center line average roughness (Ra) of 0.0
1 μm or more, preferably 0.015 μm or more and 0.042
μm or less, and the film haze at a film thickness of 25 μm is 5% or less, preferably 4% or less. Thereby, both the transparency and the slipperiness are excellent, the handleability as a laminate is good, and the support is easily peeled off after exposure, so that it cannot be suitably used as a support for a photosensitive laminate.

The thickness of the polyester film in the present invention is 10 μm or more, preferably 12 μm or more and 36 μm or less. When the thickness is less than 10 μm, the handling during the production of the laminate is poor, which is not preferable. In particular, when the thickness is less than 6 μm, even if the film surface is roughened in consideration of the handling property, the film has no stiffness, and the peeling property is low. Is bad and not preferred.

Further, the polyester film of the present invention comprises:
As described in JP-A-7-333853, as the laminated polyester film of two or more layers, the outermost layer may be composed of the polyester containing the porous silica particles, but the cost increases. Even if a laminated film is not used, a single layer film can provide sufficient transparency and slipperiness as a photosensitive layer support.

As the photoresist photosensitive layer in the present invention, any of known alkali developing type, solvent developing type and dry developing type photosensitive resin composition layers can be used.

The photosensitive laminate according to the present invention has a basic layer structure of two layers of a support film / photoresist photosensitive layer. However, usually, from the viewpoint of storage, transportation, handling, and the like, the support film / photoresist photosensitive layer is used. It is desirable to have a three-layer structure of a photoresist photosensitive layer / a protective layer.

As the protective layer, polyethylene film, polypropylene film, paper laminated with polyethylene or polypropylene, polyester film,
Cellulose-based films and nylon films are preferred. These films may be stretched films or unstretched films. These films are required not to strongly adhere to the photoresist photosensitive layer.

In the above-described two-layer structure of the support film / photoresist photosensitive layer, a solvent solution of the photosensitive resin composition is cast on the support film, roll-coated, sprayed, and the like.
It can be manufactured by applying and drying by any means such as extrusion coating. In the case of a three-layer structure of a support film / photoresist photosensitive layer / protective layer, a photoresist photosensitive layer is formed on the support film, and then a film serving as a protective layer is laminated thereon. Alternatively, it can be produced by first forming a photoresist photosensitive layer on a protective layer film, and then laminating a support film thereon.

In the photosensitive laminate of the present invention, the protective layer film is first peeled off in the three-layer structure while the two-layer structure remains as it is, and then the support film / photoresist photosensitive layer is laminated. An object is used by overlapping with a conductive base material attached to a substrate such that the surface of the photoresist photosensitive layer is in contact with the conductive base material and by pressure bonding.

[0037]

EXAMPLES The present invention will be further described below with reference to examples. The characteristics in the examples were measured by the following methods.

1. Particle size of the particles The average particle size of the primary particles is determined by dispersing silica powder so that the individual particles do not overlap as much as possible, forming a metal vapor-deposited film on the surface with a gold sputtering apparatus to a thickness of 200 to 300 mm, 10,000-300 under microscope
Observation was carried out at a magnification of 00, and image processing was performed using Luzex 500 manufactured by Nippon Regulator Co., Ltd., and the average particle size was determined from 100 particles. The average particle diameter of the particles that are aggregates of the primary particles is defined as the diameter of the 50% integrated volume fraction in the equivalent spherical distribution measured by a centrifugal sedimentation type particle size distribution analyzer.

2. Size and number of coarse particles in the film Using a universal projector, magnify 20 times with transmitted illumination,
The number of particles having a maximum length of at least μm is counted. The measurement area is 1 m ² .

3. Center line average roughness (Ra) According to JIS B0601, using a high-precision surface roughness meter SE-3FAT manufactured by Kosaka Laboratory Co., Ltd., the radius of the needle is 2 μm.
m, load 30 mg, magnification 200,000, cut off 0.
A chart was drawn under the condition of 08 mm, a portion of the measured length L was extracted from the surface roughness curve in the direction of the center line, and the center line of the extracted portion was defined as the X axis, and the direction of the vertical magnification was defined as the Y axis. When the curve is represented by y = f (x), the value given by the following equation is represented in μm.

[0041]

(Equation 1)

In this measurement, four samples are measured with the reference length set to 1.25 mm, and the average value is expressed.

4. Film haze A film haze is measured using an integrating sphere haze meter manufactured by Nippon Seimitsu Kogaku Co., Ltd. in accordance with JIS-K7105.

5. Peelability of support film after exposure The peelability of the polyester film as a support after exposure from the photoresist photosensitive layer is evaluated according to the following criteria. ：: The peeling operation was easy, and no damage was observed on the photoresist surface. X: The photoresist resin adhered to the film side in a dot-like manner or more, and damage was observed on the photoresist surface.

6 Resolution and circuit defect After the circuit is created, the circuit is visually observed and the resolution and the circuit defect are observed with a microscope, and evaluated according to the following criteria. (A) Resolution ：: A high resolution and clear circuit can be obtained. Δ: The sharpness is slightly inferior, and a decrease such as a thick line is observed. ×: Poor clarity and no practical circuit was obtained. (B) Circuit defect ：: No circuit defect is recognized. Δ: Circuit defects are observed in some places. X: The circuit has many defects and cannot be put to practical use.

7. Slipperiness (handlability) The slipperiness is evaluated in three stages through the winding step including the slitting property at the time of film formation, the step of forming the above photoresist laminate, and the circuit forming step using the laminate. . ：: There is no wrinkle in the film and there is no problem. Δ: The film sometimes wrinkles. X: Wrinkles are always formed on a part or the entire surface of the film.

Example 1 Dimethyl terephthalate and ethylene glycol were subjected to a transesterification reaction using manganese acetate as a transesterification catalyst. After the reaction was completed, antimony trioxide was used as a polymerization catalyst, phosphorous acid was used as a stabilizer, and the average of primary particles was averaged. A polycondensation reaction is performed after adding and dispersing 0.05% by weight of porous silica particles having a pore volume of 1.6 ml / g and an average particle size of 1.5 μm, which are aggregates of particles having a particle size of 0.02 μm. Thus, polyethylene terephthalate (PET) having an intrinsic viscosity of 0.65 was obtained.

Next, the obtained PET pellets were
After drying at 3 ° C. for 3 hours, it was fed to the hopper of the extruder,
The mixture was melted at a melting temperature of 290 ° C., filtered through a nonwoven fabric filter having an average opening of 24 μm made of fine stainless steel wire having a diameter of 13 μm, and cast through a slit die on a rotating drum to obtain an unstretched film. The obtained unstretched film is stretched 3.7 times in the machine direction at 90 ° C., then 4.0 times in the transverse direction at 110 ° C., and further stretched at 235 ° C. by 5 times.
Heat treatment was performed for 2 seconds to obtain a biaxially stretched film having a thickness of 25 μm.

An alkali-soluble acrylic copolymer photoresist methyl ethyl ketone solvent was applied on the biaxially stretched film using a roll coater and dried. The thickness of the photoresist photosensitive layer after drying was 25 μm. Next, from the top of the photoresist photosensitive layer, a thickness of 15 μm
A polyethylene film having a three-layer structure of a support film / photoresist photosensitive layer / protective layer was formed by laminating and press-bonding polyethylene films each having a thickness of m.

After the polyethylene film serving as a protective layer is peeled off from the laminate, it is overlaid on a copper plate provided on a glass fiber-containing epoxy resin plate so that the photoresist photosensitive layer side is in contact, and heated and pressed at a temperature of 100 ° C. In this way, they adhered. Next, the original image sheet was placed on the support film and exposed at 120 mJ / cm ² from an exposure machine, and then the support film (polyester film) was peeled off.
Subsequently, development was performed with a developer consisting of a 2% aqueous solution of sodium carbonate. A printed circuit was created.

The results are as shown in Table 1. Both the transparency and the slipperiness were good, the peelability of the support after exposure was good, and it was excellent as a photosensitive layer laminate.

Example 2, Comparative Example 1 A photosensitive laminate was produced in the same manner as in Example 1, except that the thickness of the polyester film was changed to 12 μm and 9 μm. The results are as shown in Table 1. When the thickness of the support film was 9 μm, the handling property as a laminate was poor due to poor slipperiness.

Comparative Example 2 The procedure of Comparative Example 1 was repeated, except that the thickness of the film was 5 μm and the amount of the porous silica particles added was 0.1% by weight in order to improve the slipperiness. A photosensitive laminate was manufactured. The results are as shown in Table 1. The film was insufficient in stiffness, so that the peelability was insufficient and a problem occurred in the resolution.

Example 3 and Comparative Example 3 In Example 1, the average primary particle size was 0.08 μm and 0.11 μm.
A photosensitive laminate was manufactured in the same manner as in Example 1, except that The results are as shown in Table 1. When the average particle size of the primary particles exceeded 0.1 μm, the transparency was lowered due to the generation of voids, and the resolution was lowered.

Example 4, Comparative Example 4 A filter having a wire diameter of 15 μm and an average mesh size of 27 μm according to Example 1,
Alternatively, a photosensitive laminate was produced in the same manner as in Example 1 except that a filter having a wire diameter of 17 μm and an average aperture of 30 μm was used. The results are as shown in Table 1. When the number of coarse particles exceeded 10 particles / m ² , a decrease in resolution and generation of circuit defects due to poor adhesion to the original image sheet were observed.

[Examples 5 and 6, Comparative Examples 5 and 6]
, A photosensitive laminate was produced in the same manner as in Example 1, except that the addition amount of the porous silica particles was 0.005% by weight, 0.01% by weight, 0.1% by weight, and 0.15% by weight. did. The results are as shown in Table 1, where Ra was 0.01
When the thickness is less than μm, poor slipperiness of the laminate and poor peeling of the support occur, and when the haze exceeds 5%, resolution degradation and circuit defects occur.

[0057]

[Table 1]

[0058]

According to the present invention, resolution and handleability are improved.
In addition, a photosensitive laminate having good peelability between the support film and the photoresist photosensitive layer can be provided.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 G03F 7/09 501 H05K 3/00

Claims (3)

(57) [Claims] 1. A photosensitive laminate comprising a photoresist support layer laminated on a film support having a thickness of 10 μm or more,
The film support 1) contains porous silica particles, which are aggregates of primary particles having an average particle size of 0.01 to 0.1 μm, and the number of coarse aggregated particles having a size of 50 μm or more in the film is 10 /
m ² or less, 2) a center line average roughness of the film (Ra) of the surface is 0.01
3) A photosensitive laminate, which is a biaxially stretched polyester film having a film haze of 5% or less at a thickness of 25 μm or more. 2. The photosensitive laminate according to claim 1, further comprising a protective layer on the side of the photoresist photosensitive layer. 3. The photosensitive laminate according to claim 2, wherein the protective layer is at least one selected from the group consisting of a polyethylene terephthalate film, a polyolefin film, and a polyvinylidene halide film.