JPH05297595A - Laminating method for photosensitive composition laminated body - Google Patents

Abstract

PURPOSE:To provide a method for laminating a photosensitive compsn. layer by which following property to a base material can be improved at the time of laminating and resolution can be enhanced. CONSTITUTION:A middle layer is interposed between a substrate and a photosensitive compsn. layer so that the adhesive strength of the middle layer to the photosensitive compsn. layer is made higher than that to the substrate. When the resulting photosensitive compsn. laminated body is stuck to a base material, the photosensitive compsn. layer is press-bonded to the base material by applying force from the substrate side and the substrate is removed. The layer is further press-bonded to the base material by applying force from the middle layer side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for laminating a photosensitive composition laminate (photosensitive film).

[0002]

2. Description of the Related Art Conventionally, it has been known to use a photosensitive film for forming a resist for plating or etching in the precision processing industry, for example, in the production of printed wiring boards. This photosensitive film usually consists of a support, a photosensitive composition layer, and a protective film, and while peeling off the protective film, the photosensitive resin layer together with the support is used as a base material on a heating roll. After bonding, a negative mask is placed on the support, exposed, and the support is peeled off and developed to form a resist image. recent years,
The wiring density of printed wiring boards is becoming higher and higher, so that a high-resolution resist material is desired,
Attempts have been made to improve the manufacturing yield of wiring boards by following the irregularities of the base material and reducing the unbonded portion between the photosensitive film and the base material.

In JP-A-57-21890 and JP-A-57-21891, after coating a base material with water,
A method of laminating a photosensitive film is described, but in this case the substrate surface needs to be clean in order to evenly deposit a thin layer of water. Further, when there are small-diameter through holes, etc., the water accumulated in the through holes and the photosensitive element are likely to react with each other, resulting in a drawback such as a decrease in developability.

Further, Japanese Patent Laid-Open No. 52-154363 discloses a method of laminating a liquid resin on a substrate and laminating a photosensitive element by pressure. However, there are drawbacks such as a decrease in cost and an increase in cost due to two-layer coating.

Further, Japanese Patent Publication No. 53-31670 and Japanese Patent Publication No. 51-63702 disclose that a vacuum laminator is used for lamination under reduced pressure. But,
Since the apparatus requires expensive vacuuming, it is rarely used for normal circuit formation and is used as a laminate for a permanent mask used after conductor formation. Even when laminating the permanent mask, it is desired to further improve the followability to the conductor.

[0006]

SUMMARY OF THE INVENTION The present invention eliminates the above-mentioned problems of the prior art and provides a photosensitive film which can improve the followability of the photosensitive film to the irregularities of the substrate without increasing the production cost. A laminating method is provided.

[0007]

The present invention relates to a photosensitive resin composition laminate having an intermediate layer between a support and a photosensitive composition layer, wherein the intermediate layer is more important than the adhesive force between the support and the intermediate layer. In the step of attaching the photosensitive composition laminate having a large adhesive force between the photosensitive composition layer and the base material to the base material, pressure is applied to the base material by applying force from the support side, the support is removed, and then the intermediate The present invention relates to a method for laminating a photosensitive composition laminate, which comprises applying a force from the layer side and further pressing the substrate.

The support used in the photosensitive composition laminate of the present invention is not particularly limited, but it is preferable that it is in the form of a film and has flexibility. Further, it is preferable that the test piece having a width of 2 cm has an elongation of less than 10% when a load of 500 gf is applied. If this elongation is large, wrinkles are likely to occur when pressure is applied by applying force from the support side.

The thickness of the support is usually 5 to 200 μm. Examples of the support include polyethylene terephthalate film, polypropylene film, polyethylene film, polyamide film, polyimide film and the like, and polyethylene terephthalate film is preferable.

The intermediate layer of the photosensitive composition laminate of the present invention exhibits an elongation of 10% or more at the temperature when pressure is applied by applying force from the intermediate layer side, and the stress at the time of 10% elongation is 500 gf or less. It is preferable that The elongation and the stress here can be measured by using a test piece having a width of 2 cm as the intermediate layer, and pulling the test piece with a commercially available tensile tester at a chuck interval of 2 cm and a strain rate of 2 cm / min. If the elongation is less than 10%, the ability to follow irregularities and scratches on the base material of the photosensitive layer tends to be poor. Further, when the elongation is less than 10% and the intermediate layer is broken, the photosensitive composition layer is exposed from the broken portion of the intermediate layer when the pattern exposure is performed later. Easy to cause mask contamination. There is no particular upper limit for elongation, but it is usually 750%. If the stress when stretched by 10% exceeds 500 gf, the followability tends to be poor. This stress is preferably 100 gf or less, more preferably 20 gf or less, and 10 gf
The following is particularly preferable. The lower limit of this stress is usually 1 gf.

The thickness of the intermediate layer is preferably 0.01 to 50 μm, more preferably 0.1 to 20 μm. If the thickness is too small, it tends to break, and the photocurability, workability, etc. tend to decrease, and if the thickness is too large, resolution tends to decrease.

The softening point or melting point of the intermediate layer is preferably 40 ° C. or higher. When the temperature is lower than 40 ° C., when pressure is applied by applying heat from the side of the intermediate layer, tack tends to appear on the surface of the intermediate layer to lower workability, and wrinkles may occur in the intermediate layer. There is no particular upper limit on the softening point or melting point of the intermediate layer, but the upper limit is usually 200 ° C.

The material of these intermediate layers is not particularly limited as long as it has the above-mentioned physical properties, but for example, polypropylene, polyethylene, polycarbonate, polyethylene terephthalate, polyvinyl alcohol, polyacrylate, gelatin, carboxymethyl cellulose, styrene / Examples thereof include copolymers of maleic acid and resins such as polyvinylpyrrolidone. These resins can be used alone or in combination of two or more kinds. The adhesiveness may be controlled by applying an adhesive, corona treatment, or the like to the surface of the intermediate layer or the support using these resins.

The material of the photosensitive composition layer used in the photosensitive composition laminate of the present invention is not particularly limited. For example, US Pat. No. 3,469,982 and JP-A-57-21891 are disclosed. Materials used for those shown as the photo-curable layer can be preferably used.
The thickness of the photosensitive composition layer is usually 3 to 150 μm, preferably 10 to 100 μm. If the thickness is too small, the function as a resist tends to decrease, and if the thickness is too large, edge bleeding (edge fusion) may occur when the photosensitive composition laminate is rolled. The resolution tends to decrease.

The photosensitive composition laminate of the present invention may further have a protective film adjacent to the photosensitive composition layer and on the opposite side of the intermediate layer. As a protective film,
Examples thereof include polyethylene film.

In the photosensitive composition laminate used in the present invention, the adhesive force (A ₁ ) between the support and the intermediate layer is
Adhesion between the intermediate layer and the photosensitive composition layer (A ₂ )
Must be large (A ₂ > A ₁ ). In the case of A ₁ ≧ A ₂ , it is inconvenient that when the support is removed, even though it is desired to remove only the support, it is stuck to the support and even the intermediate layer is removed. A ₁ is 100 as 180 ° peel strength
It is preferably gf / cm or less. If A ₁ is too large, the support cannot be removed smoothly. There is no particular limitation on the size of A ₂ as long as it exceeds A ₁ at 180 ° peel strength. When the intermediate layer is physically removed after pattern exposure and before development, A ₂ is 2
It is preferably less than 00 gf / cm. When the intermediate layer is chemically removed after the pattern exposure, A ₂ does not have the above-mentioned limitation. When chemically removing, the material of the intermediate layer is preferably a material that swells, dissolves, or peels off with the same developer as the developer of the photosensitive composition layer.

A known means can be used to apply a force when pressure is applied from the support side and when pressure is applied from the intermediate layer side. For example, contact elements such as rolls, squeegees, flat substrates, flat films, bag-like films and the like can be used to bring them into contact with the support or interlayer to apply force. The contact element is a spring,
The force can be obtained by a known pressure difference (decompression or pressurization by an air compressor, a vacuum pump, etc.) or a hydraulic cylinder. It is also possible to apply force in a non-contact manner with an air knife or the like.

The temperature during pressure bonding is preferably 20 to 170 ° C, more preferably 40 to 140 ° C, and particularly preferably 80 to 120 ° C. If this temperature is too low, the followability tends to be poor, and if it is too high, an odor may occur or an unwanted curing reaction may occur. The temperature at the time of crimping is the temperature of the local atmosphere in which the crimping is performed, and for securing the temperature, for example, when using a roll or the like, the temperature of the roll or the like may be set to a predetermined temperature. When using a knife or the like, the air temperature may be set to a predetermined temperature.

The force applied during crimping is 0.5 to 10 kg.
f / cm ² is preferable and 1 to 7 kgf / cm ² is more preferable. If this force is small, the followability tends to be poor, and if it is too large, damage, wrinkles, etc. tend to occur.

When a roll or the like is used, the moving speed of the base material is preferably 0.1 to 10 m / min, more preferably 0.5 to 5 m / min. If the moving speed is too low, the productivity tends to decrease, and if it is too high, the followability tends to decrease. When using a roll, the roll may be heated.

When pressure is applied by applying force from the support side and pressure is applied from the intermediate layer side, it is usual to perform pressure bonding under normal pressure, but from the viewpoint of followability, pressure bonding is performed under reduced pressure. It is preferable to carry out. In particular, it is preferable that pressure is applied by applying force from the support side under reduced pressure from the viewpoint of preventing air from being trapped between the base material and the photosensitive composition layer and in terms of workability. The pressure bonding under reduced pressure can be performed using a commercially available Hitachi vacuum laminator or the like.

The degree of reduced pressure is preferably 100 Torr or less, more preferably 60 Torr or less, and particularly preferably 30 Torr or less. The lower limit of vacuum is usually 1 torr.

Conventionally, since a photosensitive film (having no intermediate layer as in the present invention) is laminated to a substrate without wrinkles, it has a relatively large thickness as a support and a high elongation. Although a small material has to be used, there is a problem that the followability to the unevenness of the substrate is deteriorated, but in the present invention, first, with the support, pressure is applied from the support side while applying pressure. By doing so, it is possible to laminate without wrinkles, then remove the support, and apply pressure from the side of the intermediate layer having a large elongation to further press-bond, so that it is possible to follow unevenness satisfactorily. Further, since the intermediate layer can have a relatively small thickness, light scattering and the like in pattern exposure performed on the photosensitive composition layer via the intermediate layer is reduced, and resolution can be improved.

[0024]

EXAMPLES The present invention will be described with reference to examples. [Photosensitive film A] A polyester film V-20 (manufactured by Teijin Ltd.) as a support was dried with a 1% by weight ethanol solution of polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., polymerization degree: about 2000) to a dry thickness of 1 μm. So that
It was dried with warm air to form an intermediate layer. This intermediate layer was cut into a sample with a width of 2 cm to prepare a sample, and the distance between chucks was 2 cm and the strain rate was 2 cm.
When stretched at 10%, the stress is 7
It showed gf. And even if the elongation was 250%, it did not break. Next, as a photosensitive resin, 25% by weight of methacrylic acid / 75% by weight of methyl methacrylate 60 parts by weight Copolymer (weight average molecular weight 75,000) Tetrapropylene glycol diacrylate 40 parts by weight Diethylaminobenzophenone 0.2 parts by weight Benzophenone 5 parts by weight Parts Crystal Violet 0.03 parts by weight and 100 parts by weight of methyl ethyl ketone are applied to the above intermediate layer surface of the film so that the thickness after drying is 50 μm, and dried with warm air at 80 ° C. for 10 minutes to obtain a photosensitive composition. A layer was formed to obtain a photosensitive film A.

As a comparative example, a photosensitive film B having a photosensitive composition layer formed by coating only the photosensitive composition without forming an intermediate layer on a support and drying it.

Test Example 1 A glass epoxy base material (MC
LE-E67-70S: Hitachi Chemical Co., Ltd. copper foil surface with a scratch having a length of 10 cm, and the scratch depth of each scratch was deepened one by one (1 to 50 μm). Formed. These scratches are continuously weighted scratching devices (HEIDO
N (manufactured by N Corp.) was used and the load was changed.

Next, Hitachi High Temperature Laminator HLM-300
0 (manufactured by Hitachi Chemical Co., Ltd.) was roll-pressed onto the above-mentioned substrate with the photosensitive composition layers of the photosensitive films A and B facing the substrate so that the support side was in contact with the roll.
At this time, the laminating speed was 2 m / min and the roll temperature was 10
The cylinder pressure at 0 ° C. and the roll was 3 kgf / cm ² . Then, the support of the photosensitive film A having the intermediate layer was removed by hand, and the photosensitive film B having no intermediate layer was directly subjected to roll pressure bonding under the same conditions as the same laminator.

Next, a negative mask for forming a negative image having a line width of 200 μm and a stalker 21-step step tablet were placed in a direction intersecting at right angles with the length direction of scratches on the substrate, and exposed by a high pressure mercury lamp for 10 seconds. Then, using the photosensitive film A as it is, the photosensitive film B is used as it is.
In the case of using, the support was removed by hand, and spray development was carried out for 80 seconds with a 1 wt% sodium carbonate aqueous solution to obtain a resist image on the substrate. The number of remaining steps of the 21-step step tablet of Stofer is 9 steps for both photosensitive films A and B,
It had a good resist image. Furthermore, a cupric chloride etching solution (2 mol / l CuCl ₂ , 2NHCl
Aqueous solution, 50 ° C, spray pressure 2kgf / cm ² ) 1
It was sprayed for 00 seconds to dissolve the copper that was not protected by the resist, forming copper lines on the substrate. If the photosensitive film does not follow the scratches on the base material, there is a gap between the resist and the base material.Therefore, in the copper line, the etching solution penetrates at the intersection of the resist and the scratches, and the copper dissolves. , The copper line will not be connected, resulting in disconnection. The scratch depth (μm) at which this disconnection starts is taken as the followability and is shown in Table 1.
It was shown to.

[0029]

[Table 1]

Test Example 2 Using the same base material and photosensitive film as in Test Example 1 and applying pressure from the support side, the laminator was a Hitachi vacuum laminator (manufactured by Hitachi AIC Co., Ltd.). )
(Decompression degree 50 Torr, laminating speed 2 m / min, roll temperature 100 ° C., roll cylinder pressure 3 kgf / cm
Follow-up property was evaluated in the same manner as in Test Example 1 except that ² ) was replaced, and the results are shown in Table 2.

[0031]

[Table 2]

[0032]

According to the present invention, when laminating the photosensitive composition laminate, it is possible to improve the followability to the substrate and the resolution.

Claims (2)

[Claims] 1. A photosensitive composition laminate having an intermediate layer between a support and a photosensitive composition layer, wherein the adhesive force between the intermediate layer and the photosensitive composition layer is more than the adhesive force between the support and the intermediate layer. In the step of bonding the photosensitive composition laminate having a large number to the base material, pressure is applied to the base material by applying force from the support side, the support is removed, and then force is applied from the intermediate layer side to further add the base material. A method for laminating a photosensitive composition laminate, which comprises press-bonding the photosensitive composition laminate. 2. The intermediate layer of the photosensitive composition laminate exhibits an elongation of 10% or more at a temperature when pressure is applied to the base material by applying a force from the intermediate layer side, and a stress when the elongation is 10%. Is 500 gf or less, The method for laminating a photosensitive composition laminate according to claim 1.