JPH1012604A - Formation of highly heat-resistant insulating resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively form a resin film having a heat resistance which is by no means inferior to that of a polyimide film and excellent electrical characteristics on the surface of a substrate so that the film can surely follow the surface shape of the substrate by printing or applying polyamide-imide resin ink to one or both surfaces of the substrate and curing the ink by heating. SOLUTION: A polyimide-imide resin film is formed on one or both surfaces of a substrate by printing or applying polyamide-imide resin ink to one or both surfaces of the substrate and curing the ink by heating. For example, a conductor pattern is formed by forming an etching resist layer composed of a resin film 1 on a substrate 2 formed by laminating a metallic layer 2b upon a base film 2a composed of a polyimide film and etching the metallic layer 2b of the substrate 2. During the forming process of the resin film 1, the polyamide-imide resin ink is screen-printed on the entire surface of the metallic layer 2b of the substrate 2 so that the film thickness of the ink becomes >=10μm after curing, and then, the ink is cured by heating the ink for five minutes at 150 deg.C after the ink is preheated for four minutes at 90 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-heat insulating material having excellent heat resistance on one or both sides of a semiconductor substrate or a printed wiring board, excellent electrical properties, and capable of forming a low-cost and uniform resin film. The present invention relates to a method for forming a conductive resin film.

[0002]

2. Description of the Related Art On the front and / or back surface of a substrate such as a semiconductor substrate or a printed wiring board, there are various types of electrical connections between internal wiring and surface mount components, and between the external and external parts. Patterned conductors are formed, and an insulating layer made of a resin film is further laminated to protect these conductors and mounted components and to insulate the conductors. Further, a plurality of conductors and insulating layers may be alternately formed.

[0003] A part of the conductor is connected to a through hole formed in the substrate through an electroless plating or a plating layer obtained by laminating an electrolytic plating on the through hole. Solder is applied to connect the outer conductor.

[0004] When conducting, plating, soldering, or the like on the front surface or the back surface of these substrates, a resist layer composed of a resin film cures a liquid resist agent or adheres a film composed of the resist agent. It is formed.

[0005] The liquid resist agent is called ink and is formed into a predetermined pattern by, for example, screen printing, and is left on the substrate as an insulating layer after processing such as etching, plating, and soldering. And those that are peeled off after processing such as soldering.

The insulating layer is generally formed by printing or applying a resin ink on a substrate and then curing the resin ink. However, there are cases where the insulating layer is printed in a pattern as in the case of the resist layer and where the resin ink is applied over the entire surface of the substrate. There is.

[0007] The liquid material for forming the resist layer and the insulating layer is called an ink, and generally includes a resin component, a filler such as silica, talc, barium sulfate, and alumina, carbon black, cyanine blue, cyanine green, titanium yellow, and phthalocyanine. It consists of a coloring agent such as green or titanium oxide or a coloring agent such as an organic dye, and a solvent, and is classified into a heat-drying ink, a heat-curable ink, an ultraviolet-curable ink, a liquid developing ink, and the like, depending on the curing method. Have been.

The heat-drying ink is used not only for etching resists but also for plating resists and filling holes, and is an ink for evaporating and evaporating an organic solvent by heating to obtain a dry film.

The heat-drying type ink used for the etching resist is required to be suitable for screen printing and to be resistant to various etching liquids and easily peelable with an alkaline aqueous solution after the etching treatment. Therefore, as the resin component, modified rosin resin, acrylic resin and phenol resin are used, and as the filler, silica, talc, barium sulfate, alumina, etc. are used,
Carbon black, cyanine blue, titanium oxide, or the like is used as a coloring pigment, and a high-boiling organic solvent is used as a solvent.

The heat-drying type ink used for the plating resist is not only suitable for screen printing, but also resistant to various plating solutions such as copper sulfate, pyrophosphoric acid, copper, gold, solder, and the like. It is necessary to be able to easily peel off with an alkaline aqueous solution or a stripping solution such as trichloroethylene or trichloroethane. For this reason, as the resin component, the same resin as the etching resist is used for the alkali stripping type, and a chlorinated polyolefin, a coumarone resin, a rubber-based resin, or the like is used for the solvent stripping type.

Further, the heat-drying type ink used for filling the holes is a protective ink which is embedded in the holes so that the through-hole portions are not etched at the time of etching. After polishing, etching resist printing is performed. The components are the same as those of the etching resist, but it is necessary that the loss (volume shrinkage) after drying is small and the edge of the through hole is not easily chipped during polishing.

The heat-curable ink is used when heat resistance is required, such as a solder resist, a marking, and a permanent mask, and is an ink for obtaining a cured film by addition polymerization or polycondensation by heating. A thermosetting resin is used as the resin component, and a melamine-modified epoxy resin has been conventionally used. However, since formalin is generated at the time of curing, almost a pure epoxy resin is currently used. As fillers, silica, talc,
Barium sulfate or the like is used, and cyanine green, cyanine blue, titanium yellow, titanium oxide, or the like is used as a coloring pigment, and additives such as a high-boiling organic solvent, an antifoaming / leveling agent, and a curing agent are added. As the curing agent, a tertiary amine, an imidazole derivative, a phenol resin or the like is used. Further, there are a two-pack type in which a curing agent is mixed at the time of use and a one-pack type in which a curing agent is mixed at the time of ink production.

The ink used as the solder resist ink is an insulating coating for preventing connection failure of component terminals due to solder bridges and uneven soldering at the time of soldering, and prevents solder from adhering to unnecessary portions. Is an ink used for protecting a conductor portion from an external environment. Therefore, including resistance to post flux at the time of soldering and heat resistance at 240-260 ° C molten solder,
Electrical properties such as solvent resistance, chemical resistance, moisture resistance, insulation resistance and dielectric constant must be excellent. Thermosetting inks are widely used in industry for their excellent properties.

The heat-curable ink used as the marking ink is also called a symbol ink, and is an ink for printing symbols and characters indicating the position and type of parts on a substrate, and has a composition of a color pigment. Other than the above, it is the same as the heat-curable solder resist ink.

The permanent mask ink is used for a plating resist of a full additive method and a plating resist that also serves as a solder resist of a partly additive method.
In order to require resistance to thick electroless copper plating in addition to the characteristics as a solder resist, plating resistance is enhanced by partially modifying an epoxy resin and a curing agent.

The ultraviolet curable ink is 100 to 3800
This is an ink that is irradiated with ultraviolet rays of nm and cured by radical polymerization or photocation polymerization, and is used for etching resists, plating resists, solder resists, markings, and the like. This ultraviolet curable ink uses the same resin component as the heat-drying type etching resist as the resin component, uses silica and talc as the filler, and uses cyanine green, cyanine blue, titanium oxide, and carbon as the coloring pigment. A photopolymerization initiator is added using black or the like and a reactive diluent monomer such as various (meth) acrylate oligomers such as epoxy acrylate, polyester acrylate, and urethane acrylate, and (meth) acrylates as a solvent.

The UV-curable etching resist ink is a resin component similar to the heat-drying type etching resist, and is UV-curable by using (meth) acrylate instead of an organic solvent as a solvent. is there.

The ultraviolet curing type plating resist ink is
A resin component of a heat-drying plating resist, which uses (meth) acrylic acid ester instead of an organic solvent.
Printing methods other than screen printing (JP-B-59-28479)
JP-A-57-60394) and ink (see Japanese Patent Publication No. 57-60394).

The ultraviolet-curable solder resist ink is
Compared to heat-curable solder resist, the curing time is shorter, there is no solvent, there is no drying of the plate, the dimensional stability of the substrate is good because it is not heated, etc. There is a limit to the curing of this material, and there are some concerns about adhesion and moisture resistance.

Ultraviolet-curable marking inks, like solder resists, are limited in terms of color tone, but are frequently used because they are fast-curing and hard to clog.

The liquid development type resist is cured by using both ultraviolet curing technology and heat curing technology.
It is used as an etching resist, a plating resist, a solder resist, a permanent mask, and the like.

Although liquid development type etching resist inks and plating resist inks have been used in the past, they have hardly been used due to the development of dry films. However, due to the increased density of printed circuit boards, there is concern about the resolution and adhesion of dry films, and these liquid resists have been reviewed, and solder resist inks and permanent masks have been developed again that should be noted. It is getting.

The liquid development type solder resist ink is a partially acrylated resin of an epoxy resin (JP-A-60-208).
No. 377), an epoxy resin such as a resin obtained by combining a linear polymer and an acrylic oligomer, a photopolymerization type obtained by modifying various polymers, a photodimerization type obtained by sharing a chalcone group and an epoxy group, and the like. Alone or in combination with a heat-curable resin such as an epoxy resin, a filler such as silica and talc, a photopolymerization initiator, a curing agent, a coloring agent such as phthalocyanine green and an organic dye, and an organic solvent. Etc.

[0024] As a method of construction, there are a non-contact exposure type using a parallel light exposure apparatus and a contact exposure type in which a dried film is obtained and then a film is brought into close contact and exposed. The exposure type is widely used because many of the existing types can use existing equipment. Depending on the developing method, there are a solvent developing type and a water developing type using a weak alkaline solution. The latter is expected to grow in terms of the cost of the developing solution, the developing machine and the air pollution.

As a coating method, besides a screen coating method, a curtain coater (see JP-A-58-62636) and a roll coater (see JP-A-57-164595)
U.S. Pat.

Although the liquid developing type permanent mask ink is still under development, its resistance to electroless plating is slightly lower than that of the heat-curable type and has reached a usable level.

[0027] By the way, in the present day when the density of the substrate is remarkably developing, in order to achieve a higher definition of the circuit pattern, it is required that the insulating layer has a more excellent electrical property, especially a dielectric property. In addition, it is required to increase heat resistance against heat generation during use. In addition, in order to increase the definition of a circuit pattern, the same is required for a solder resist layer and a plating resist layer.

With the demands of the electric and electronic industries, recently, attempts have been made to use a polyimide film having excellent heat resistance and electric characteristics as an insulating layer.

[0029]

However, in the case of polyimide ink, polyimide as a base polymer is hardly dissolved in a solvent. Therefore, the polyimide ink is used in a state of amic acid, which is a precursor thereof, and is used in an amount of 250 to 350. An imidization reaction (ring-closing reaction to an imide ring) is caused by heating at a high temperature of ℃ to obtain a polyimide film.

When such high-temperature heating is performed, thermal degradation of the substrate or the like or TAB (Tape Automated B
warping is caused in the film which is a substrate for bonding. More specifically, for example, as a result of the TAB having a width of 35 mm, both ends are warped by 2 to 3 mm, it becomes difficult to perform optical automatic alignment, etc. Therefore, there was a problem that cracks occurred in the coating film.

In addition, defects such as scratches on the substrate surface and scratches on the back surface of the film are greatly affected, and there are drawbacks such as poor apprehension of the ability to follow the substrate surface. It is necessary to form a pattern, and there is also a disadvantage that the total cost is increased.

Further, in a method of forming a polyimide resin film by applying a polyamic acid solution on a substrate and heat-treating the solution,
Although a small amount of the prepolymer remains, a limit is imposed on the improvement of the electric properties, particularly the dielectric properties.

The present invention solves the above technical problems, reliably follows the substrate surface, is free from the influence of defects such as scratches on the substrate surface and the resin film, and has a heat resistance comparable to that of the polyimide film. An object of the present invention is to provide a method for forming a high heat-resistant insulating resin film capable of forming a resin film having excellent properties and excellent electrical characteristics at low cost.

[0034]

According to the present invention, in order to achieve the above object, a polyamide-imide resin film is formed by printing or coating a polyamide-imide resin ink on one or both surfaces of a substrate and curing the ink by heating. The technical means that it is characterized by forming.

As described above, by dissolving the polyamide imide cured in advance in the organic solvent, the resin component can reliably follow the substrate surface, and the electrical characteristics and the like can be reduced by the scratches on the substrate surface and the resin film. Disturbance can be reliably prevented.

Further, by heating and curing the polyamide-imide resin ink, it becomes possible to form a resin film having high heat resistance and uniform electrical characteristics comparable to polyimide resins.

In addition, the resin film can be formed by a simple and inexpensive procedure of printing or applying a polyamide-imide resin ink and heating.

Hereinafter, the present invention will be described in detail. In the present invention, the substrate on which the resin film is formed includes a semiconductor substrate such as a semiconductor wafer and a printed wiring board, and among the semiconductor substrates, a semiconductor having a single structure or a semiconductor whose structure is polarized by doping or the like. A semiconductor substrate in which a conductor layer such as a metal layer is laminated on one or both sides of the substrate, and a semiconductor substrate in which a conductor layer and an insulating layer covering the same are laminated on one or both sides of the substrate. .

The printed wiring board includes a substrate, a single-sided printed conductor plate having a conductor layer laminated on one side of the substrate, a double-sided printed conductor plate having conductor layers laminated on both sides of the substrate, and a multi-layer laminated substrate. It includes a printed conductor plate such as a multilayer printed conductor plate having a conductor layer formed between materials, and a printed conductor plate having a conductor layer and an insulating layer laminated on one or both surfaces.

The conductor layer includes, for example, a layer laminated over the entire surface of the base material, such as an earth electrode plate, and a layer patterned for forming circuit components such as filters and resistors and wiring. It is.

The substrate of the printed conductor board may be a synthetic resin film substrate such as a polyester film, a vinyl chloride film, a phenol film, an epoxy film, a polyfluoroethylene film (Teflon film), a polyimide film, or a paper or phenol film. , Consisting of composite or laminated films such as paper / epoxy, glass cloth / epoxy, tetron / epoxy, glass mat / polyester, glass cloth / Teflon, glass cloth / polyimide, etc.
So-called synthetic resin substrates and ceramic substrates can be mentioned as examples.

The polyamide-imide resin ink used in the present invention is, for example, a commercially available polyamide-imide solvent, preferably γ-butyl lactone, N-methylpyrrolidone, triglyme, N, N-dimethylformamide, N, N-
Dimethylacetamide, N-methyl-2-pyrrolidone,
N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylphosphoric triamide, dimethylacetamide, benzonitrile, dioxane, N-methylcaprolactam,
It is obtained by dissolving in a polar solvent such as dimethyl sulfoxide.

In this case, the compounding ratio of the polyamideimide is not particularly limited, but it is preferable that the viscosity is such that printability or coating suitability can be obtained. For example, when printing on a substrate by screen printing, screen printability is obtained. It is preferable that the solid concentration is about 20 to 40%, more preferably about 24 to 37%, and the solid concentration is 27 to 33%.
It is most preferred that the

However, the components of the polyamide-imide resin ink are not limited to these polyamide-imides and solvents, but include conventionally used fillers such as silica, talc, barium sulfate and alumina, carbon black, and the like. Coloring pigments such as cyanine blue, cyanine green, titanium yellow, phthalocyanine green, and titanium oxide, or coloring agents such as organic dyes, and different kinds of resin components such as polyimide may be added as modifiers.

As the solvent, the above-mentioned polar solvent may be used alone or as a mixed solvent. As the mixed solvent, a mixed solvent of polar solvents and two or more polar solvents may be used. A mixed solvent with one or more nonpolar solvents,
A mixed solvent of one polar solvent and one or more non-polar solvents is included. Here, examples of the non-polar solvent include xylene and toluene.

The polyamide-imide resin ink of the present invention can be printed or applied directly on the front or back surface of a substrate of these substrates, or printed or applied on a metal layer laminated on the substrate. You may print or apply | coat on the resin film laminated | stacked on the base material.

Of course, in the method of the present invention, when printing or coating a polyamide-imide resin ink on a substrate,
In order to increase the adhesion between the substrate surface and the polyamide-imide resin film, it is also possible to form an undercoat layer on the substrate and print or apply a polyamide-imide resin ink on the undercoat layer.

In the present invention, when printing a polyamide-imide resin ink on a substrate, various known printing methods such as screen printing, letterpress printing, intaglio printing, and gravure printing may be used. Solid printing can also be performed, but when the film thickness is, for example, 10 μm or less, a polyamideimide-based resin ink is printed in a predetermined pattern by, for example, screen printing to easily form a resin film having a predetermined pattern. be able to.

If the thickness of the resin film exceeds, for example, 10 μm, the accuracy of the pattern formed by printing may decrease due to dripping of the ink. After that, it is recommended that an unnecessary portion is etched using, for example, an electron beam (ion beam) to form a resin film in a predetermined pattern.

In the present invention, examples of the method for applying the polyamideimide resin ink to the substrate include a screen coating method, a method using a roll coater, a curtain coater, a spray and the like, and a dipping method.

In the present invention, the above-mentioned polyamide-imide resin ink is printed or coated on a substrate and then cured by heating. The curing conditions are such that the solvent evaporates according to the composition of the polyamide-imide resin ink. The temperature may be set as low as possible, for example, at 100 to 150 ° C. for several minutes to 1 hour.
It may be set to about 0 minutes.

When the polyamide-imide resin ink is cured in this manner, it has heat resistance comparable to that of the polyimide resin, and has electrical resistance such as insulation resistance, withstand voltage, volume resistivity, surface resistivity, and dielectric constant. A uniform resin film of polyamideimide having good characteristic is formed.

According to the present invention, as described above, a polyamideimide-based resin ink is printed or coated on one or both sides of a substrate and cured by heating to form a polyamideimide-based resin film. The surface of the substrate can be reliably followed, whereby the effect of filling the wound on the substrate surface with a resin component to repair the wound or preventing the resin film from being damaged can be obtained. Accordingly, it is possible to reliably prevent the electrical characteristics and the like from being disturbed by scratches on the substrate surface and the resin film.

In the present invention, a uniform resin film made of a polyamide-imide resin can be formed by heating and curing a polyamide-imide resin ink, so that high heat resistance comparable to that of a polyimide resin can be obtained. Having
It is possible to form a resin film having electrical characteristics with better uniformity than a polyimide resin. In addition, the resin film can be formed by a simple and inexpensive procedure of printing or applying a polyamideimide-based resin ink and heating to evaporate the solvent.

In particular, as in the case of polyimide ink,
Rather than using as a precursor (prepolymer), a precured polyamideimide is used as a base polymer, so that the prepolymer remains and does not deteriorate electrical properties, especially dielectric properties. It is.

[0056]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings, but the present invention is not limited to these embodiments.

FIG. 1 shows an etching of a resin film 1 according to one embodiment of the present invention on a base material 2 in which a metal layer 2b is laminated on an upper surface of a base film 2a made of a polyimide film (manufactured by DuPont, trade name: Kapton). A step of forming a resist layer and etching a metal layer 2b of the base material 2 to form a conductor pattern is shown.

In this embodiment, in the resin film forming step shown in FIG.
After screen-printing the polyamideimide-based resin ink over the entire surface so that the film thickness after curing becomes 10 μm or more, for example, 40 μm, preheat at 90 ° C. for 4 minutes,
Heat at 0 ° C. for 5 minutes to cure.

The metal layer 2b is made of, for example, aluminum having a thickness of 50 μm (equivalent to JIS H4000, A1050P).
The upper surface of which has been preliminarily degreased and cleaned, and surface-treated using Chemicoat # 155 (manufactured by Chemicoat).

The screen used for this screen printing was a stainless mesh 400 (wire diameter: 18 μm, porosity: 51%), emulsion thickness: 40 μm, and washed with γ-butyl lactone followed by acetone.

The polyamide-imide resin ink is obtained by dissolving commercially available polyamide-imide in a solvent, and has a solid content of 31 using γ-butyl lactone as a main solvent.
% Was used. The color of this solution is pale yellowish white,
The viscosity is 180 Pa · s (1800 Ps) at 25 ° C.
In and, TI value is 2.5η ₁ / η _10, a glass transition temperature of 231 ° C..

The moisture absorption of this solvent is 0.1%,
The plate emulsion swelling ratio of the solvent is 4.0%.

The resin film 1 obtained by curing the above solution has a tensile strength of 78 MPa, an elastic modulus of 2.1 GPa, an elongation at break of 13%, is soft, and has a heat resistant temperature [start of weight loss. Temperature (Td ₅ )] is 355 ° C., and it is recognized that heat resistance is not inferior to polyimide resin.

In the above-mentioned heat treatment, preheating is performed at 90 ° C. for 4 minutes in order to prevent local hardening of the solution. This preheating can be omitted since there is no danger of local hardening of the solution during this temperature rise. After the above-described heat treatment is performed, the resin film 1 may be vitrified by heating at, for example, 150 ° C. for about 5 minutes.

The resin film 1 obtained by curing the solution in this way becomes uniform over its entirety,
In particular, those having extremely excellent electrical characteristics can be obtained with good reproducibility.

The insulation resistance of the resin film 1 is 2.5 ×
10 ¹¹ Ω (measurement method IPC-FC-240), withstand voltage of 1,000 V DC × 30 s and no abnormality (measurement method
IPC-FC-240), and the volume resistivity is 3.5 ×
10 ¹⁵ Ωcm (measurement method JIS C 6481), and the surface resistivity is 2 × 10 ¹⁵ Ω (measurement method JIS C 6481).
6481) and a dielectric constant of 1 MHz 3.5 (measured in accordance with JIS C 6481), indicating that there is no inferiority to the electrical properties of the polyimide resin.

After that, in a resist mask forming step shown in FIG. 1B, an etching resist film 3 having a predetermined pattern is printed on the cured resin film 1 by, for example, screen printing, and then is patterned as shown in FIG. In the resin film pattern forming step shown in (1), the conductor film 1 is formed into the same pattern as the conductor pattern to be formed later by, for example, dry etching using an electron beam (ion beam).

After patterning the resin film 1 in this manner, in the conductor pattern forming step of FIG. 1D, the metal layer 2b is etched by a conventional method, and the metal layer 2b is formed into a predetermined conductor pattern. Is done.

The resin film 1 is dissolved and removed at the time of washing with an aqueous alkali solution after the etching of the metal layer 2b.

After the washing, a polyamide-imide resin ink is filled between the pattern of the metal layer 2b and the resin film 1, and the surface of the metal layer 2b is coated with the polyamide-imide resin ink and cured by heating. Thus, it is possible to insulate between patterns of the metal layer 2b and between the metal layer 2b and the outside of the substrate.

This method of forming a conductor pattern is applied to, for example, the substrate 2 made of a single-sided printed wiring conductor plate shown in FIG.
The present invention can also be applied to a base material 2 made of a double-sided printed wiring conductor plate shown in FIG.

In the case of the base material 2 made of a double-sided printed wiring conductor plate, a conductor pattern is formed only on the upper metal layer 2b as shown in FIG. A conductor pattern may be formed only on 2b.

When the conductor pattern is formed on only one side of the base material 2 made of a double-sided printed wiring conductor plate, the metal layer 2b on the opposite side is prevented from being etched during the formation of the conductor pattern. As shown in FIG. 4 or FIG. 5, the resin film 1 is formed over the entire opposite surface in accordance with the procedure of FIG. After the etching of the conductor pattern is completed, the resin film 1 on the opposite surface is dissolved and removed at the time of washing with an alkaline aqueous solution.

FIG. 6 schematically shows a cross section of a substrate in which an insulating layer (overcoat) made of the resin film 1 formed by the procedure shown in FIG.
1 schematically shows a cross section of a substrate in which an insulating layer made of a resin film 1 having a predetermined pattern is formed on both surfaces of a base material 2 in accordance with the procedure shown in FIGS. 1 (a) to 1 (c).

Here, the resin film 1 is laminated without patterning the metal layer 2b. Of course, an insulating layer made of the resin film 1 is similarly formed on the patterned metal layer 2b. be able to.

A detailed description of the method of forming the resin film 1 as an insulating layer will be omitted to avoid duplication.

FIG. 8 shows a substrate 2 according to another embodiment of the present invention.
A procedure for forming a plating resist layer made of a resin film 1 having a predetermined pattern on one side of the metal layer 2b and forming a plating layer 4 on the surface of the metal layer 2b exposed from this pattern by electroless copper plating will be described.

In this embodiment, in the resin film pattern printing step shown in FIG. 8A, the polyamideimide solution is subjected to pattern printing by, for example, screen printing so that the film thickness after drying becomes less than 10 μm, and then cured by heating. Film 1 made of polyamideimide having a predetermined pattern
Is formed. Thereafter, in an electroless copper plating step shown in FIG. 8B, a plating layer 4 is deposited on the surface of the metal layer 2b exposed from the pattern by a conventional method.

Since the thickness of the electroless plating layer 4 is relatively small, for example, as shown in one embodiment of the present invention,
When the resin film 1 having a thickness of not less than μm is formed, a conductive metal such as copper may be further deposited on the plating layer 4 by electrolytic plating.

The method of forming the plating layer 4 on the surface of the metal layer 2b in this way is, for example, as shown in FIG. 9, if the plating layer 4 is formed only on the base material 2 made of a single-sided printed wiring conductor plate. First, as shown in FIG. 10, a plating layer 4 is formed on both sides of a substrate 2 made of a double-sided printed wiring conductor plate, or as shown in FIG. It can be applied to the case where the layer 4 is formed.

In this case, after the resin film 1 is formed, the resin film 1 is used as an etching resist to form the metal layer 2.
b is etched to form a conductor pattern, and a space between any part of the conductor pattern and the resin film 1 is further filled by a conventional method, or as shown in FIG. Then, an insulating layer may be formed between the conductor pattern and the resin film 1 by heating and curing, followed by electrolytic copper plating.

FIG. 12 shows that an insulating layer also serving as a plating resist made of a resin film 1 formed according to another embodiment of the present invention is formed on a substrate 2 on which a conductor pattern and a through hole 2c are formed. The conductor pattern is formed by a conventional method or according to the present invention, and the through hole 2c is formed by a conventional method before or after the formation of the conductor pattern.

Also, FIG. In the resin film pattern printing process of FIG. 12A, a resin film 1 having a predetermined pattern is formed by the procedure of FIG. 8A, and in the plating process of FIG. Through-hole plating is performed.

FIG. 13 schematically shows a cross section of the substrate formed by the procedure shown in FIG. 12, and 2d indicates a semi-through hole (HIV).
Is shown.

FIG. 14 is a view showing another embodiment of the present invention. After forming an etching resist / plating resist layer composed of a laminated resin film 5 on one surface of a substrate 2, a conductor pattern is formed, and a plating layer 4 is formed. 4 shows a step of forming a terminal portion.

This laminated resin film 5 is composed of a resin film 1 made of a polyamide-imide resin and a dissimilar resin film 6 laminated so as to cover the resin film 1. First, in the resin film pattern forming step shown in FIG. The resin film 1 is formed in a predetermined pattern by the procedure shown in FIG.

In the step of forming the laminated resin film shown in FIG. 14B, for example, an organic solvent peeling type acid- and alkali-resistant resist ink or an alkali peeling type acid-resistant resist ink is placed on the patterned resin film 1. After printing in a predetermined pattern by screen printing, the laminated resin film 5 is formed by heat drying or heat curing, and thereafter, the laminated resin film 5 is etched in a conductor pattern forming step shown in FIG. Metal layer 2 as resist
The conductor pattern is formed by etching b.

Thereafter, in the pattern insulating step of FIG. 14D, for example, the insulation of the resin film 1 between any part of the conductor pattern and the pattern of the laminated resin film 5 is performed by the procedure of FIG. A layer is formed, thereby insulating the conductor patterns between the conductor patterns and on both sides thereof from the outside of the substrate.

Further, thereafter, in the plating step of FIG. 14E, the plating layer 4 is formed between the conductor patterns by electroless plating using the laminated resin film 5 and the resin film 1 between the patterns as a plating resist. .

When an organic solvent peeling type acid- and alkali-resistant resist ink is used as the different resin film 6, the metal layer 2b is etched to form a through hole (or H).
After the formation of the IV) 2c, only the different resin film 6 is peeled off, and the through-hole (or the HIV) 2c of the metal layer 2b is formed.
By performing electroless plating after exposing the periphery of the metal layer 2b, it is possible to form the through-hole plating layer 4 having lands on the surface of the metal layer 2b.

FIG. 15 schematically shows a cross section of a substrate in which a terminal portion made of a plating layer 4 is formed on one surface of a base material 2 made of a single-sided printed wiring conductor plate by the procedure of FIG.
14 schematically shows a cross section of a substrate in which terminal portions made of a plating layer 4 are formed on both surfaces of a base material 2 made of a double-sided printed wiring conductor plate by the procedure shown in FIG.

In these embodiments, the laminated resin film 5 in which only one layer of a different kind of resin film 6 is laminated on the resin film 1 is formed. However, as shown in FIG. 17 or FIG.
It is also possible to form a three-layer laminated resin film 8 in which layers of different types of resin films 6 and 7 are laminated, or to form a multi-layer laminated resin film in which a multi-layered different type of resin film is further laminated on the resin film 1.

[0093]

As described above, according to the present invention, a polyamide-imide resin ink is formed by printing or coating a polyamide-imide resin ink on one or both surfaces of a substrate and curing the ink by heating. The resin component can be made to reliably follow the substrate surface, whereby the effect of filling the wound on the substrate surface with the resin component to repair the damage or preventing the resin film from being damaged can be obtained. Further, by this operation, an effect of reliably preventing an adverse effect such as disturbance of electrical characteristics due to scratches on the substrate surface or the resin film can be obtained.

Further, according to the present invention, a uniform resin film made of a polyamide-imide resin can be formed by heating and curing the polyamide-imide resin ink, so that high heat resistance comparable to that of a polyimide resin can be obtained. Having
The effect of being able to form a resin film having electrical characteristics with excellent uniformity as compared with a polyimide resin is obtained.

In particular, as in the case of polyimide ink,
Rather than using as a precursor (prepolymer), a polyamideimide that has been cured in advance is used as a base polymer, so that the prepolymer remains and deteriorates electrical characteristics, particularly dielectric characteristics. Therefore, it is possible to obtain a highly reliable resin film with good reproducibility.

In addition, the effect that the resin film can be formed by a simple and inexpensive procedure of printing or applying the polyamide-imide resin ink and heating to the extent that the solvent is evaporated is obtained.

In the present invention, in particular, when a polyamideimide resin ink is printed in a predetermined pattern, the pattern can be formed by printing. Therefore, the pattern formation can be performed at a lower cost than when the pattern is formed by etching after curing. The effect that can be obtained is obtained.

In the present invention, when the different resist layer is formed in a predetermined pattern covering the polyamideimide resin film, for example, after forming a through hole or HIV by etching, only the different resist layer is removed. By performing plating thereafter, there is obtained an effect that through-hole plating having lands on the surface can be performed.

[Brief description of the drawings]

FIG. 1 is a process diagram of a manufacturing process of a substrate to which the present invention is applied.

FIG. 2 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 3 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 4 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 5 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 6 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 7 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 8 is a process chart of a manufacturing process of a substrate to which the present invention is applied.

FIG. 9 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 10 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 11 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 12 is a process chart of a manufacturing process of a substrate to which the present invention is applied.

FIG. 13 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 14 is a process chart of a manufacturing process of a substrate to which the present invention is applied.

FIG. 15 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 16 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 17 is a schematic cross-sectional view of a substrate formed according to the present invention.

FIG. 18 is a schematic cross-sectional view of a substrate formed according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin film 2 Base material 2a Base film 2b Metal layer 3 Etching resist film 4 Plating layer 5 Laminated resin film 6 Dissimilar resin film 7 Dissimilar resin film 8 Three-layer laminated resin film

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Claims (9)

[Claims] 1. Forming a polyamide-imide resin film by printing or applying a polyamide-imide resin ink on one or both surfaces of a substrate and curing it by heating to form a polyamide-imide resin film. Method. 2. The method according to claim 1, wherein the polyamide-imide resin ink is printed in a predetermined pattern. 3. The method for forming a high heat resistant insulating resin film according to claim 1, wherein a different kind of resist layer is laminated on the cured polyamideimide resin film. 4. The method according to claim 3, wherein the different resist layer is formed in a predetermined pattern covering the polyamide-imide resin film. 5. The method for forming a high heat resistant insulating resin film according to claim 2, wherein the pattern is a permanent mask pattern. 6. The method for forming a high heat resistant insulating resin film according to claim 2, wherein the pattern is an etching resist pattern. 7. The method for forming a highly heat-resistant insulating resin film according to claim 2, wherein the pattern is a plating resist pattern. 8. The method for forming a high heat resistant insulating resin film according to claim 2, wherein the pattern is a solder resist pattern. 9. The method for forming a high heat-resistant insulating resin film according to claim 2, wherein the pattern is a filling pattern.