JP2008117929A - Adhesive tape for solder resist protection, its manufacturing method, and surface roughness control method of solder resist - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive tape for solder resist protection which can attain protection of a solder resist layer and improvement of junction reliability between the solder resist layer and an article adhered to it at the same time in less processes wherein surface roughness of the adhesive layer is controlled, a manufacturing method of the adhesive tape for solder resist protection and a surface roughness control method of the solder resist which controls a solder resist surface using the adhesive tape for solder resist protection to prescribed surface roughness. <P>SOLUTION: The adhesive tape for solder resist protection consists of a base material film (A), an adhesive layer (B) formed in one surface of the base material film (A) and a mold release film (C) applied to the adhesive layer (B). In the adhesive tape for solder resist protection, a surface of the adhesive layer (B) in contact with the mold release film (C) has enough surface roughness to allow the solder resist layer to be firmly adhered to an article to be adhered thereto when the solder resist layer is protected by applying the adhesive layer (B). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an adhesive tape for protecting a solder resist, a method for producing the same, and a method for controlling the surface roughness of the solder resist. More specifically, the surface roughness of the pressure-sensitive adhesive layer can be achieved in a small number of steps, which can protect the solder resist layer and at the same time improve the reliability of the bonding between the solder resist layer and the solder resist layer. Solder resist protecting adhesive tape, method for producing the solder resist protecting adhesive tape for laminating the release film, and applying the solder resist protecting adhesive tape to the unexposed solder resist to identify the unexposed solder resist surface The present invention relates to a method for controlling the surface roughness of a solder resist that controls the surface roughness of the solder.

In the printed circuit board manufacturing process, a solder resist layer is provided on the substrate surface to protect the surface of the substrate and prevent short circuits. A liquid photosensitive resist is mainly used for the solder resist layer.
This solder resist layer adheres to or adheres to various substances, such as being bonded to other parts via resin, or creating a wiring pattern by copper plating. It is necessary to have a certain degree of adhesion and adhesion with the thing.

  Conventionally, a solder resist layer is formed by applying a liquid resist to the entire surface of a substrate and drying it, masking this with a photomask, exposing and developing, and then dissolving and removing unexposed portions to form a wiring pattern. It is. When the high-tack liquid resist is coated on both sides of the substrate, this causes a problem that the resist adheres to the photomask at the time of contact exposure. In order to prevent the resist from adhering to the photomask, an adhesive tape for protecting the photomask is used. In the photomask protective adhesive tape, a release treatment layer for preventing liquid resist adhesion is provided on the back surface of the tape substrate.

  Photomask protective adhesive tape is generally provided with a pressure-sensitive adhesive layer on one side of a transparent film such as a polyester film, and a release treatment layer (generally an organopolysiloxane (ie silicone) release agent) on the opposite side. .

  The substrate coated with the liquid resist is masked with a photomask having a photomask protecting adhesive tape bonded thereto, and after contact exposure and development in a vacuum, an unexposed portion is dissolved and removed to form a wiring pattern.

  FIG. 1 is a flow sheet showing an example of the above-described conventional substrate manufacturing process, in which a photomask protecting adhesive tape is bonded to a photomask 1 and closely exposed to a substrate coated with a liquid resist.

  According to the above method, because the release treatment layer of the adhesive mask for photomask protection is in close contact with the liquid resist, the surface roughness of the solder resist layer after exposure is formed by the surface roughness of the release treatment layer, In this case, the surface roughness of the solder resist layer is 1.0 μm or less, and the adhesion between the substrate surface and the sealing resin is lowered. Although the method of enlarging the surface roughness of the base film of the adhesive tape for photomask protection is also conceivable, it is difficult to control the surface roughness because the release treatment layer is coated.

  As a method for controlling the roughness of the substrate surface, a method of treating the substrate surface with pear has been proposed. (See Patent Document 1.) According to this method, the surface roughness of the solder resist surface is controlled by a separate process such as jet scrub method, liquid honing method, wire brush method, cleansing method, sanding method, or grinding removal. ing.

  However, in this method, since the surface roughness of the solder resist layer can be arbitrarily controlled only by applying another process, there is a problem that the number of steps increases, contamination due to another process occurs, or the cost increases.

Japanese Patent Laid-Open No. 9-55579

  An object of the present invention is to provide a pressure-sensitive adhesive that can achieve the protection of the solder resist layer and the improvement of the bonding reliability of the solder resist layer and the material bonded to the solder resist layer in a small number of steps, in view of the prior art. Solder resist protecting adhesive tape whose surface roughness is controlled, a method for producing the solder resist protecting adhesive tape for laminating a release film, and pasting the solder resist protecting adhesive tape to an unexposed solder resist The present inventors have found that the problems of the prior art can be solved by a solder resist surface roughness control method for controlling the unexposed solder resist surface to a specific surface roughness, thereby completing the present invention.

  As a result of diligent research to solve the above problems, the present inventors have found that the base film (A), the pressure-sensitive adhesive layer (B) formed on one side of the base film (A), and the pressure-sensitive adhesive layer It is a pressure sensitive adhesive tape for solder resist protection consisting of a release film (C) to be bonded to (B), and the surface of the pressure sensitive adhesive layer (B) in contact with the release film (C) is the pressure sensitive adhesive layer (B ) Is applied to protect the solder resist layer, the solder resist protective pressure-sensitive adhesive tape having a surface roughness sufficient to allow the solder resist layer to adhere firmly to the solder resist layer and the base film (A) After forming the pressure-sensitive adhesive layer (B) on one side of the surface, the surface roughness (Ra) by the center line average roughness on the surface in contact with the pressure-sensitive adhesive layer (B) is 1.0 μm to 3.0 μm. Viscosity for solder resist protection to laminate a certain release film (C) A method for manufacturing a adhesive tape and a method for controlling the surface roughness of a solder resist using the adhesive tape for protecting a solder resist, wherein the release film (C) of the adhesive tape for protecting a solder resist is peeled off and then adhered. The adhesive layer (B) is affixed to the unexposed solder resist, and the surface of the unexposed solder resist in contact with the adhesive layer (B) is 1.0 μm to 3.0 μm in terms of surface roughness (Ra) based on the center line average roughness. By controlling the surface roughness of the solder resist to be controlled, the surface roughness of the layer is controlled at the same time as the protection of the solder resist layer, thereby improving the bonding reliability between the solder resist layer and the material to be bonded to it with fewer steps. It has been found that the problems of the prior art can be solved and the present invention has been completed.

That is, according to the first invention of the present invention, the base film (A), the adhesive layer (B) formed on one side of the base film (A), and the adhesive layer (B) are bonded. Solder resist protecting adhesive tape consisting of a release film (C),
The surface of the pressure-sensitive adhesive layer (B) in contact with the release film (C) is firmly bonded to the surface to which the solder resist layer is adhered when the pressure-sensitive adhesive layer (B) is applied to protect the solder resist layer. An adhesive tape for protecting a solder resist characterized by having a sufficient surface roughness is provided.

  According to the second invention of the present invention, in the first invention, the surface of the pressure-sensitive adhesive layer (B) in contact with the release film (C) has a surface roughness (Ra) due to the center line average roughness. 1.0 μm to 3.0 μm, a solder resist protecting adhesive tape is provided.

  According to the third invention of the present invention, in the first invention, the surface in contact with the pressure-sensitive adhesive layer (B) of the release film (C) has a surface roughness (Ra) due to centerline average roughness. 1.0 μm to 3.0 μm, a solder resist protecting adhesive tape is provided.

  According to the fourth invention of the present invention, in any one of the first to third inventions, the surface in contact with the pressure-sensitive adhesive layer (B) of the release film (C) is surface-roughened by embossing. An adhesive tape for protecting a solder resist, characterized in that is controlled. Is provided.

  According to the fifth invention of the present invention, in the invention of any one of the first to third inventions, the surface of the release film (C) that contacts the pressure-sensitive adhesive layer (B) is roughened by mat processing. An adhesive tape for protecting a solder resist, characterized in that is controlled.

  According to the sixth aspect of the present invention, after the pressure-sensitive adhesive layer (B) is formed on one surface of the base film (A), the center line on the surface in contact with the pressure-sensitive adhesive layer (B) is further formed thereon. For protecting a solder resist according to any one of the first to fifth inventions, wherein a release film (C) having a surface roughness (Ra) based on an average roughness of 1.0 μm to 3.0 μm is laminated. A method for producing an adhesive tape is provided.

  According to a seventh aspect of the present invention, in the sixth aspect, the surface roughness (Ra) of the release film (C) is controlled by embossing or matting. A method for producing an adhesive tape for resist protection is provided.

According to an eighth aspect of the present invention, there is provided a method for controlling the surface roughness of a solder resist using the solder resist protective adhesive tape according to any one of the first to seventh aspects,
After peeling off the release film (C) of the adhesive tape for protecting the solder resist, the adhesive layer (B) is applied to the unexposed solder resist, and the surface in contact with the adhesive layer (B) of the unexposed solder resist is centered. There is provided a method for controlling the surface roughness of a solder resist, characterized in that the surface roughness (Ra) based on the line average roughness is controlled to 1.0 μm to 3.0 μm.

The pressure-sensitive adhesive tape for solder resist protection of the present invention has a control of the surface roughness of the pressure-sensitive adhesive layer, so that the solder resist layer can be protected and the bonding reliability between the solder resist layer and the one bonded thereto can be improved. Improvement can be achieved simultaneously with fewer steps.
In addition, the method for producing a pressure-sensitive adhesive tape for solder resist protection of the present invention is a simple method of laminating a specific release film on a pressure-sensitive adhesive tape for solder resist protection in which the surface roughness of the pressure-sensitive adhesive layer is controlled. Can be manufactured.
Further, the method for controlling the surface roughness of the solder resist of the present invention is a simple method in which an adhesive layer in which the surface roughness of the adhesive tape for protecting the solder resist is controlled is attached to an unexposed solder resist, The unexposed solder resist surface can be controlled to a specific surface roughness.
As a result, it is possible to improve the bonding reliability of the solder resist layer to be bonded to the solder resist layer at the same time as the protection of the solder resist layer in a small number of steps. Environment resistance against vibration, acceleration, high temperature, etc. can be improved. Therefore, the present invention is suitably used for a two-layer board or a flexible printed board having a pattern on both sides.

  Hereinafter, the adhesive resist protecting adhesive tape of the present invention will be described in detail.

1. Solder resist protecting adhesive tape The solder resist protecting adhesive tape of the present invention comprises a base film (A), an adhesive layer (B) formed on one side of the base film (A), and an adhesive layer (B ) Is a pressure-sensitive adhesive tape for solder resist protection composed of a release film (C) to be bonded to the surface of the pressure-sensitive adhesive layer (B) in contact with the release film (C). A solder resist protective pressure-sensitive adhesive tape characterized by having a surface roughness sufficient to adhere firmly to the solder resist layer adhered to the solder resist layer when affixed to protect the solder resist layer. The pressure-sensitive adhesive tape for solder resist protection of the present invention is such that the surface of the pressure-sensitive adhesive layer (B) in contact with the release film (C) has a surface roughness by sticking to the pressure-sensitive adhesive layer (B) of the release film (C). It is characterized by being controlled.
In addition to protecting the solder resist and controlling the surface roughness of the solder resist, the base film (C) and the pressure-sensitive adhesive layer (B) used for the adhesive tape for protecting the solder resist of the present invention are solder resist. After being affixed to the substrate, a photomask is further laminated, and exposure, development, dissolution removal of unexposed portions, and the like are performed. Therefore, it is necessary that the light transmittance including ultraviolet rays is high.

(1) Base film (A)
The base film (A) is not particularly limited as long as it has high light transmittance including ultraviolet rays, and examples of the base film include polyester, polyethylene terephthalate (PET), polypropylene, polyethylene, vinyl chloride, Examples thereof include those made of resins such as polystyrene, polyimide, polycarbonate, and cellophane.
As a base film (A) used for this invention, general purpose PET, polypropylene, etc. which are transparent films are preferable. In particular, a PET film having a thickness of 4 to 25 μm, more preferably 6 to 12 μm is more preferable from the viewpoint of transparency and thickness accuracy.

  Moreover, as long as it does not have a bad influence on this invention, the said base film (A) unwinds the plasma processing for improving the adhesiveness with an adhesive, and the base film wound by roll shape. In some cases, a process such as a process of imparting slipperiness may be performed so that the base films are not attached to each other and unwound. Various additives such as colorants, fillers, UV absorbers, light stabilizers, heat stabilizers, gloss control agents, lubricants, antistatic agents, antibacterial agents, antifungal agents, flame retardants, and antifriction agents It can also be added as appropriate.

  In addition, as the antistatic treatment, the base film (A) can be coated or blended with an antistatic agent. By the antistatic treatment, when the release film is peeled off, generation of static electricity is suppressed, and a decrease in circuit pattern reliability due to adhesion of foreign matters such as dust can be substantially eliminated. The antistatic treatment means is not particularly limited as long as it can provide the desired antistatic performance, but a method of blending an antistatic agent such as a surfactant into the base film, base material The method of vapor-depositing or coating on the film surface is mentioned.

(2) Adhesive layer (B)
As the pressure-sensitive adhesive layer, a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, or the like can be used. An acrylic pressure-sensitive adhesive is preferred from the viewpoints of transparency, non-discoloration, resolution, and the like.

  As the acrylic pressure-sensitive adhesive, in particular, a copolymer obtained by copolymerizing an alkyl group (meth) acrylic acid alkyl ester having 4 to 12 carbon atoms as a main component and a small amount of a functional monomer or a modified monomer. Coalescence is preferably used.

  Examples of the (meth) acrylic acid ester include n-butyl acrylate, isobutyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, decyl acrylate, isodecyl acrylate, 2-methacrylic acid 2- Examples include ethylhexyl, isooctyl methacrylate, decyl methacrylate, isodecyl methacrylate, lauryl methacrylate and the like.

  Examples of the functional monomer include a monomer having a hydroxyl group, a monomer having a carboxyl group, a monomer having an amide group, a monomer having an amino group, and a monomer having a pyrrolidone ring. Examples of the monomer having a hydroxyl group include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate.

  Examples of the monomer having a carboxyl group include α, β-unsaturated carboxylic acids such as acrylic acid and methacrylic acid, monoalkyl maleates such as monobutyl maleate, maleic acid, fumaric acid, and crotonic acid. Maleic anhydride also provides the same (co) polymerization component as maleic acid.

  Examples of monomers having an amide group include alkyl (meth) acrylamides such as acrylamide, dimethylacrylamide, and diethylacrylamide, N-alkoxymethyl (meth) acrylamides such as N-butoxymethylacrylamide, N-ethoxymethylacrylamide, and diacetone acrylamide. Illustrated. Examples of the monomer having an amino group include dimethylaminoethyl acrylate. Examples of the monomer having a pyrrolidone ring include N-vinylpyrrolidone.

  A particularly preferred acrylic pressure-sensitive adhesive includes a copolymer of acrylic acid alkyl ester and acrylic acid.

In the present invention, in particular, the addition of a crosslinking agent to the pressure-sensitive adhesive causes cross-linking between the polymers, thereby increasing the internal cohesive force of the pressure-sensitive adhesive, and transferring the surface roughness of the release film to the pressure-sensitive adhesive surface. It is desirable to add a cross-linking agent to the pressure-sensitive adhesive because the properties are improved.
Examples of such cross-linking agents include post-addition cross-linking agents such as isocyanate, epoxy, aziridine, organometallic, chelate and amine, di (meth) acrylate, tri (meth) acrylate, tetra (meth) ) Copolymerizable crosslinking agents such as acrylates and divinyl compounds are exemplified.

Specific examples of the copolymerizable crosslinking agent include di (meth) acrylates obtained by combining polymethylene glycols such as hexamethylene glycol and octamethylene glycol and (meth) acrylic acid; polyethylene glycol, polypropylene glycol, and the like. Di (meth) acrylate obtained by combining polyalkylene glycols with (meth) acrylic acid; tri (meth) acrylate such as trimethylolpropane tri (meth) acrylate and glycerin tri (meth) acrylate; and pentaerythritol tetra Examples include tetra (meth) acrylates such as (meth) acrylate.
Among these, in order to transfer the unevenness of the release film onto the pressure-sensitive adhesive surface after lamination with the release film, a post-addition type crosslinking agent is preferable, and specifically, hexamethylene diisocyanate (HMDI) is particularly preferable.

  The amount of the crosslinking agent is preferably 1.0 to 5.0 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive from the viewpoint of maintaining the surface roughness of the pressure-sensitive adhesive. More preferably, it is desirable to mix at a ratio of 2.0 to 4.0 parts by weight. If the amount is less than 1.0 part by weight, the uneven shape of the pressure-sensitive adhesive surface may change after the release film is peeled off. If the amount is more than 5.0 parts by weight, an excess crosslinking agent that does not participate in the crosslinking reaction remains in the pressure-sensitive adhesive. It is not preferable.

  That is, as the pressure-sensitive adhesive layer (B) in the present invention, a pressure-sensitive adhesive in which 2.0 parts by weight of HMDI as a crosslinking agent is added to a copolymer of acrylic acid alkyl ester and acrylic acid is a preferable combination. By this combination, in addition to the functions generally required as a pressure-sensitive adhesive layer as the pressure-sensitive adhesive layer in the present invention, in particular, the surface roughness control function of the pressure-sensitive adhesive layer surface when the release film (C) is stuck and peeled off Is preferably exhibited. In this invention, the surface roughness (Ra) by centerline average roughness in the surface which is not in contact with the base film of the pressure-sensitive adhesive layer after release film (C) is 1.0 μm to 3.0 μm. It is preferable.

  Moreover, additives, such as a tackifier, a plasticizer, and a stabilizer, can be added to the pressure-sensitive adhesive as necessary. These are preferably blended within a range that does not impair optical properties such as light transmittance and hue. In addition, an antistatic agent can be coated or blended in the pressure-sensitive adhesive.

  For example, in the present invention, in order to improve the adhesive strength, a so-called tackifier component can be blended and used. A tackifier component, also called a tackifier, is a substance that is blended into an elastomer to improve its adhesive function, and is usually an amorphous oligomer with a molecular weight of several hundred to several thousand, which is a liquid or solid heat at room temperature. It is a plastic resin.

  The type of tackifier is not particularly limited, such as natural resin typified by rosin resin, terpene resin, aliphatic, aromatic, copolymer petroleum resin, phenolic resin, xylene resin, etc. A synthetic resin system is exemplified. These may be used alone or in combination of two or more.

  The tackifier usually inhibits light transmission, so that it does not increase the haze value, and it is preferable to use a rosin resin and a terpene phenol resin together in order to achieve suitable adhesive performance.

  5-80 weight part is preferable with respect to 100 weight part of adhesives, and, as for the compounding quantity of a tackifier component, it is more preferable that it is 8-50 weight part. If the amount of the tackifier is too small, the necessary adhesive strength cannot be obtained. On the other hand, if the amount is too large, the problem of adhesive residue tends to occur, and it becomes practically difficult to use.

  In this invention, it is preferable that the adhesive force of a base film (A) and an adhesive layer (B) is 200 gf / 25mm or more from the point of adhesive residue. Moreover, it is preferable that the adhesive force with the mold release film demonstrated below is 1.0-10.0 gf / 25mm from the point of easy peeling manufacture with an adhesive, and the maintenance of the uneven surface shape of an adhesive. .

  The pressure-sensitive adhesive layer (B) of the present invention is formed by being applied to the base film (A). The thickness of the pressure-sensitive adhesive layer after drying is preferably in the range of 1 to 10 μm, more preferably 2 It is in the range of ˜8 μm. If the thickness is less than 1 μm, the adhesive strength to the solder resist may be insufficient. On the other hand, if it exceeds 10 μm, sufficient light transmittance may not be obtained.

(3) Release film (C)
In this invention, a release film (C) controls the surface roughness of an adhesive layer (B), when it affixes on the said adhesive layer and peels.
As the release film (C) used in the present invention, the surface roughness (Ra) due to the center line average roughness on the surface of the release film (C) in contact with the pressure-sensitive adhesive layer (B) is the bonding reliability of the substrate. Therefore, the thickness is preferably 1.0 μm to 3.0 μm. More preferably, it is 1.0-2.0 micrometers. If it is smaller than 1.0 μm, the effect of improving the bonding reliability of the substrate hardly appears, and if it is larger than 3.0 μm, the sealing resin impregnation into the substrate surface irregularities may be insufficient, which is not preferable.

  As the release film (C), a synthetic resin film or a polyethylene-laminated paper subjected to a release treatment can be used, and among them, a general-purpose PET film is released using a silicone release agent. Those subjected to are preferably used. In the case of a general-purpose polyethylene (PE) film, it can be used without being subjected to a release treatment. In the case of a PE film, it has been confirmed that fine unevenness is formed on the surface of the pressure-sensitive adhesive when peeled from the pressure-sensitive adhesive.

  As a method for arbitrarily controlling the surface roughness of the release film (C), embossing, matting and the like are suitable. In this case, the surface roughness is preferably 1.0 μm to 3.0 μm in terms of the surface roughness (Ra) based on the average roughness of the center line from the bonding reliability of the substrate.

  This release film (C) is peeled off from the pressure-sensitive adhesive tape before the pressure-sensitive adhesive tape for protecting a solder resist of the present invention is applied to the surface of the solder resist.

2. The manufacturing method of the adhesive tape for solder resist protection The manufacturing method of the adhesive tape for solder resist protection of this invention forms an adhesive layer (B) in the single side | surface of a base film (A), and is the said adhesive layer (B). A release film having a surface roughness (Ra) of 1.0 μm to 3.0 μm on the surface that is not in contact with the base film (A) and having a center line average roughness on the surface in contact with the pressure-sensitive adhesive layer (B) ( C) is laminated. More preferably, it is 1.0-2.0 micrometers. Similarly to the above, if it is smaller than 1.0 μm, the effect of improving the bonding reliability of the substrate is hardly exhibited, and if it is larger than 3.0 μm, the impregnation of the sealing resin into the substrate surface irregularities may be insufficient.

  As a method of forming the pressure-sensitive adhesive layer (B) on one side of the base film (A), the prepared pressure-sensitive adhesive solution is layered on the base film with a gravure coater, comma coater, roll coater or the like. The pressure-sensitive adhesive tape is formed by coating to a thickness and laminating the release film (C) after drying.

  As a method for laminating the release film (C), a normal laminating method can be used as long as the object of the present invention is not impaired.

3. Solder Resist Surface Roughness Control Method The solder resist surface roughness control method of the present invention is a method in which the adhesive layer of the adhesive tape for solder resist protection is applied to an unexposed solder resist, and the adhesive layer of the unexposed solder resist and The surface to be contacted is controlled to 1.0 μm to 3.0 μm by the surface roughness (Ra) by the center line average roughness.

  Specifically, when protecting a solder resist layer such as a printed circuit board, an unexposed portion after the adhesive is bonded to a liquid resist with an adhesive tape having an arbitrary surface roughness, exposed and developed. By dissolving and removing the film to form a wiring pattern, the surface roughness of the solder resist layer can be arbitrarily controlled without applying another process, and the bonding reliability of a printed circuit board or the like is improved.

  FIG. 2 shows a flow sheet of a substrate manufacturing process according to the present invention. Since the adhesive layer (B) of the adhesive tape for protecting a solder resist of the present invention was applied to the surface of the unexposed solder resist on the solder resist surface after dissolving and removing the unexposed portion, the adhesive layer (B ) Is transferred to the surface of the solder resist. In this way, the surface of the solder resist is controlled to an arbitrary surface roughness, and thereafter, for example, when forming the wiring pattern, the adhesion of the wiring pattern is good, and the bonding reliability of the printed circuit board is improved.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
The measurement method used was as follows.
Surface roughness Ra: a value measured using a laser microscope (manufactured by Keyence, VK8500: magnification 200 times, area 1.4 mm × 1.0 mm).
Solder resist surface Gloss%: Value measured by an apparatus of IG330 manufactured by HORIBA, Ltd. The smaller the value, the rougher the surface.
Bonding reliability (bonding strength) of encapsulating resin: Measured by a thermal shock test method (150 ° C.-65 ° C. × 500 cycles) as “O” when resin peeling did not occur and “X” when resin peeling occurred.

(Example 1)
10 parts by adding 2 parts by weight of an isocyanate-based crosslinking agent (trade name “Coronate L-45” manufactured by Nippon Polyurethane Co., Ltd.) to an adhesive obtained by copolymerizing 5 parts by weight of acrylic acid and 95 parts by weight of butyl acrylate as an adhesive % Toluene solution was applied to a 12 μm substrate film 1 (E-12, manufactured by Teijin DF Co., Ltd.) and dried so that the thickness after drying was 3 μm, and matted to a surface roughness Ra of 1.7 μm. A release-treated surface of a 25 μm thick polyester film 2 (TS-25, manufactured by Teijin DF Co., Ltd.) was bonded to obtain an adhesive tape for protecting the substrate.

(Example 2)
A PE film (manufactured by Tamapoly, GF-30) having a thickness of 30 μm was bonded to the pressure-sensitive adhesive surface of the same pressure-sensitive adhesive tape as that obtained in Example 1 to obtain a pressure-sensitive adhesive tape for substrate protection.

(Comparative Example 1)
A polyester film film having a thickness of 25 μm (Toyobo Co., Ltd., E-7002) was bonded to the pressure-sensitive adhesive surface of the same pressure-sensitive adhesive tape as obtained in Example 1 to obtain a pressure-sensitive adhesive tape for substrate protection.
The surface roughness Ra of the polyester film used in the comparative example is 0.05 μm.

  A substrate obtained by screen-printing a liquid resist (manufactured by Taiyo Ink, AUS308) on a glass epoxy substrate so as to be 35 μm after drying is dried at 80 ° C. for 30 minutes to protect the substrate shown in the above-mentioned Examples 1 and 2 Comparative Example 1. The adhesive tape was laminated and irradiated with 500 mJ with a UV exposure apparatus.

[Evaluation]
The surface roughness of the adhesive surface of the adhesive tape for protecting a substrate obtained in each of the above Examples and Comparative Examples, and the surface roughness of the solder resist layer, Gloss, the solder resist layer for the glass epoxy substrate produced using them. The bonding strength of the sealing resin was measured.
These results are shown in Table 1.

As is clear from Table 1, the bonding strength of the substrates prepared using the substrate protecting adhesive tapes obtained in Examples 1 and 2 showed better results than those obtained in Comparative Example 1.
That is, when Example 1 or 2 is compared with Comparative Example 1, which is a specific matter of the production method of the present invention, “the surface of the pressure-sensitive adhesive layer that is not in contact with the substrate film is attached and peeled off from the release film. In Comparative Example 1 manufactured by a method that does not satisfy the requirement that the surface roughness is controlled by the above, in Example 1 or 2 using the adhesive tape for solder resist protection of the present invention, the surface of the adhesive It can be seen that by controlling the roughness, the solder resist surface roughness can be controlled, and the bonding strength reliability of the sealing resin using the solder resist whose surface roughness is controlled is improved.

FIG. 1 is a flow sheet showing a conventional printed circuit board manufacturing method. FIG. 2 is a flow sheet showing the printed circuit board manufacturing method of the present invention. FIG. 3 is a side sectional view showing an embodiment of the adhesive tape for protecting a solder resist of the present invention.

Explanation of symbols

1: Base film 2: Adhesive layer 3: Release film

Claims (8)

A solder resist comprising a base film (A), a pressure-sensitive adhesive layer (B) formed on one side of the base film (A), and a release film (C) bonded to the pressure-sensitive adhesive layer (B). A protective adhesive tape,
The surface of the pressure-sensitive adhesive layer (B) in contact with the release film (C) is firmly bonded to the surface to which the solder resist layer is adhered when the pressure-sensitive adhesive layer (B) is applied to protect the solder resist layer. An adhesive tape for protecting a solder resist, characterized by having a sufficient surface roughness.   The surface of the pressure-sensitive adhesive layer (B) in contact with the release film (C) has a surface roughness (Ra) based on the average roughness of the center line of 1.0 μm to 3.0 μm. The adhesive tape for solder resist protection of description.   The surface of the release film (C) in contact with the pressure-sensitive adhesive layer (B) has a surface roughness (Ra) based on the average roughness of the center line of 1.0 μm to 3.0 μm. The adhesive tape for solder resist protection of description.   The surface of the release film (C) in contact with the pressure-sensitive adhesive layer (B) has a surface roughness controlled by embossing, for solder resist protection according to any one of claims 1 to 3. Adhesive tape.   Solder resist protection according to any one of claims 1 to 3, wherein the surface of the release film (C) in contact with the pressure-sensitive adhesive layer (B) has a surface roughness controlled by mat processing. Adhesive tape.   After the pressure-sensitive adhesive layer (B) is formed on one side of the base film (A), the surface roughness (Ra) based on the center line average roughness on the surface in contact with the pressure-sensitive adhesive layer (B) is further 1. 6. The method for producing a pressure-sensitive adhesive tape for protecting a solder resist according to claim 1, wherein a release film (C) having a thickness of 0 to 3.0 [mu] m is laminated.   The method for producing a pressure-sensitive adhesive tape for solder resist protection according to claim 6, wherein the surface roughness (Ra) of the release film (C) is controlled by embossing or matting. A method for controlling the surface roughness of a solder resist using the adhesive tape for solder resist protection according to claim 1,
After peeling off the release film (C) of the adhesive tape for protecting the solder resist, the adhesive layer (B) is applied to the unexposed solder resist, and the surface in contact with the adhesive layer (B) of the unexposed solder resist is centered. A method for controlling the surface roughness of a solder resist, characterized in that the surface roughness (Ra) based on line average roughness is controlled to 1.0 μm to 3.0 μm.

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