JPS62217698A - Metal base multilayer printed board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a flexible printed circuit board in which at least a thin crosslinked product of a mixture of two types of ethylene copolymers and a conductive metal layer are laminated on a metal base printed circuit board. This invention relates to a metal-based multilayer printed circuit board having a layer. More specifically, the metal-based multilayer printed circuit board is an ethylene copolymer having (A) at least ethylene units and at least one unit selected from the group consisting of carboxylic acid units, dicarboxylic acid units, anhydride units thereof, and halfester units thereof. and (B) an uncrosslinked mixture of an ethylene copolymer having at least ethylene units and at least one type of unit selected from the group consisting of hydroxyl units, amino units and epoxy units, or a thin-walled material having at least a crosslinked product thereof, and a conductive material. The present invention relates to a metal-based multilayer printed circuit board formed by laminating a flexible printed circuit board on which at least a metal layer is laminated on a metal-based printed circuit board, and the object thereof is to provide a board with excellent heat dissipation characteristics and which can be multilayered. That is.

Indigo X Ω and] Recent electronic devices are rapidly becoming smaller, lighter, thinner, and more densely packaged. In particular, printed wiring boards began to be commercialized for consumer equipment such as radios, and are now being used in industrial equipment such as telephones and computers, supported by mass production and high reliability.

Flexible printed wiring boards were initially used as a substitute for electric wires and cables, but their flexibility not only allows for high-density three-dimensional mounting in narrow spaces.
In order to withstand repeated bending, its use is expanding as a composite component that functions as a wiring, cable, or connector for the moving parts of electronic devices.

Currently, the materials used as three-dimensional wiring materials in devices such as cameras, electric desktop calculators, telephones, and printers are:
A wiring pattern is formed using a flexible copper-clad board in which electrolytic copper foil of 35 microns is adhered to both or one side of a polyimide or polyester film with a thickness of about 25 microns. This wiring pattern is also coated with a through hole coating and further coated with a coverlay on both sides and the outer layer.

Current flexible printed wiring boards generally use polyimide or polyester resin films as base materials, but polyester films not only have poor solder heat resistance, but also absorb water from the epoxy adhesive used to bond them to copper foil. Since the coefficient of thermal expansion is high and the coefficient of thermal expansion at 20° C. to 250° C. is also large, through-hole connection reliability is lacking.

Furthermore, during production, curing is sometimes carried out using a steam press at 170°C, which tends not only to reduce adhesiveness between resins but also to reduce flexibility when multi-layered.

On the other hand, polyimide film is soldered at the normal soldering temperature (26
It has the advantage that it can be easily soldered at temperatures above 0°C), but it has the disadvantage that polyimide resin is hygroscopic and has poor surface activity, making it extremely difficult to bond with metal foil. There are drawbacks. To solve this problem of adhesion, the general method is to apply a chemical treatment using caustic soda, a chromic acid mixture, aluminum hydroxide, etc. to the surface of the film, and then bond it with an adhesive. It is. However, even if these methods are used for adhesion, it is not possible to obtain a printed circuit board with sufficient adhesion, and the chemical resistance and heat resistance are poor. In addition, thermosetting adhesives with excellent heat resistance (for example,
In the method of bonding with metal foil using epoxy resin,
Polyimide film coated with adhesive must be layered with metal foil and then heated, pressed and cured using a press for approximately 1 to 20 hours, which poses problems in terms of productivity, mass production, cost, etc. Furthermore, since it has high hygroscopicity, it has to be dehydrated under heat and reduced pressure before the soldering process.

In addition, high-speed ICs can be directly applied to these flexible substrates.
As power becomes higher, there is an increasing need to simultaneously solve heat dissipation and multilayer technology. That is, in a multilayer substrate, the problem is how to increase the heat dissipation that could not be obtained and increase the density.

From the above, the present invention does not have these problems (defects), and it is possible to obtain a printed circuit board that not only has good heat dissipation properties but also can be multilayered by a simple method. That's true.

. According to the present invention, these problems can be solved by the fact that the fully bending based multilayer printed circuit board has (A) "at least ethylene units, carboxylic acid units, dicarboxylic acid units, anhydride units thereof, and halfester units." and at least one type of unit selected from the group consisting of, and the content of ethylene units is 30 to 99.
5% by weight of an ethylene-based copolymer""Ethylene-based copolymer (A) J] 1 to 99% by weight and (B
) "An ethylene copolymer consisting of at least ethylene units and at least one type of unit selected from the group consisting of hydroxyl units, amino units, and epoxy units, and having an ethylene unit content of 30 to 99.5% by weight." j [hereinafter referred to as "ethylene copolymer (B)"] 99
A metal base formed by laminating a flexible printed circuit board, which is formed by laminating at least a thin material having a thickness of 3 microns to 5 mm and a conductive metal layer, on a metal base printed circuit board and having at least 1% by weight of a cross-linked mixture. Multilayer printed circuit board, can be solved by. The present invention will be explained in detail below.

(A) Ethylene copolymer (A) The ethylene copolymer (A) used in the present invention contains at least ethylene units and a group consisting of carboxylic acid units, dicarboxylic acid units, anhydride units thereof, and halfester units thereof. The present invention is an ethylene copolymer containing 30 to 99.5% by weight of at least one type of ethosene unit (hereinafter referred to as "second component (A)").

This ethylene copolymer (A) contains at least the second component (
A) Copolymers that can be obtained by copolymerizing the following monomers, multi-component copolymers of these and other monomers, and acid anhydrides in these copolymers. Examples include those obtained by hydrolyzing and/or alcohol-denaturing a physical group Z).

Typical examples of monomers containing at most 25 carbon atoms include abilylic acid, methacrylic acid, and crotonic acid.
fi unsaturated monocarboxylic acids and maleic acid, phthalic acid, tetrahydrophthalic acid, 4-methylcyclohexane-4-ene-1,2-carboxylic acid, itaconic acid, citraconic acid and pink l co<:2.24 ) -hept-5-ene-2,3-dicarboxylic acid and other unsaturated dicarboxylic acids having 4 to 50 carbon atoms, and anhydrides of these unsaturated dicarboxylic acids.

Further, other monomers having at most 30 carbon atoms (preferably 10 or less) such as methyl (meth)acrylate, ethyl (meth)acrylate, hydroxymethyl (meth)acrylate, and diethyl fumarate may be used.
and vinyl esters having at most 30 carbon atoms such as vinyl acetate and vinyl propionate.

Among the above ethylene copolymers (A), copolymers of ethylene and unsaturated dicarboxylic anhydrides or multicomponent copolymers of these and unsaturated dicarboxylic esters and/or vinyl esters are hydrolyzed and The dicarboxylic anhydride units of these copolymers can be converted into dicarboxylic acid units or Hafester units by/or modification with alcohol. In the present invention, an ethylene copolymer (A) obtained by replacing part or all of the unsaturated dicarboxylic anhydride units of the copolymer or multicomponent copolymer with dicarboxylic acid units or halfester units is also preferred. It can be used with

To carry out the hydrolysis, the ethylene copolymer (A
) in the presence of a catalyst (e.g. tertiary amine) in an organic solvent (e.g. toluene) that dissolves the copolymer.
It can be obtained by reacting with water at a temperature of ~100'C for 0.5~10 hours (preferably ~6 hours, preferably 3~6 hours) followed by neutralization with acid.

To carry out the alcohol modification, the ethylene copolymer (A) can be obtained by the solution method or kneading method described below.

The solution method is similar to the case of hydrolysis, in which the reaction is carried out in an organic solvent in the presence or absence of the above-mentioned catalyst (the reaction is slow in its absence).
This method involves reacting for 2 minutes to 5 hours (preferably 2 minutes to 2 hours, preferably 15 minutes to 1 hour) at the reflux temperature of the alcohol-v used in .

On the other hand, chaos! The li method uses the ethylene copolymer (A) 10
Usually 0.01-1.0 parts by weight (preferably 0.05 to 0.5 parts by weight) of tertiary amine and dicarboxylic acid units in the copolymer. is 0
．． 1 to 3.0 times the mole (preferably 1.0 to 2.0 times the mole) of saturated alcohol is added at a temperature above the melting point of the ethylene copolymer (A) but below the boiling point of the alcohol to be used, which is usually and several minutes to several tens of minutes (preferably 10 minutes to 30 minutes) using a mixing machine such as the Banbury Mixer-1 extruder used in the field of synthetic resins.
) This is a method of widening while kneading.

The saturated alcohol used in the above modification with alcohol is a linear or branched saturated alcohol having 1 to 12 carbon atoms, and includes methyl alcohol, ethyl alcohol, and -butyl alcohol.

In the case of the above hydrolysis and in the case of modification with alcohol, the conversion rate to dicarboxylic acid and the halfesterization rate are both 0.5 to 100%, and 10.0 to 100%.
100% is desirable.

The ethylene units in this ethylene copolymer (A) are 30
-99.5% by weight, preferably 30-89.0% by weight, particularly preferably 35-89.0% by weight. Also,
The proportion of carboxylic acid units, their anhydride units and halfester units in the copolymer is 0.1 to 70% by weight in total, preferably 0.5 to 70% by weight, particularly 0.5% by weight. ~60% by weight is preferred.

If an ethylene polymer in which the proportion of carboxylic acid units, anhydride units and halfester units in this ethylene copolymer (A) is 0.1% by weight is used, the ethylene copolymer described below When heating and crosslinking the composite (B), not only the crosslinking is incomplete, but also the adhesion to the metal layer is poor. On the other hand, even if the content exceeds 70% by weight, the characteristics of the present invention are exhibited, but it is not necessary to exceed 70% by weight, which is not preferable from the viewpoint of production and economy.

In addition, when using a multicomponent copolymer containing the unsaturated carboxylic acid ester and/or vinyl ester, the total amount thereof is usually at most 70% by weight, and 6% by weight.
It is preferably 0% by weight or less. If an ethylene copolymer with a copolymerization ratio of unsaturated dicarboxylic acid ester and/or vinyl ester exceeds 70% by weight is used, the softening point of the copolymer will be high and the fluidity will be low at temperatures below 150°C. This is not only undesirable because it damages the environment, but it is also undesirable from an economic point of view.

(B) Ethylene copolymer (B) In addition, the ethylene copolymer (B) used in the present invention (
B) contains at least ethylene units and hydroxyl units,
At least one unit selected from the group consisting of amide 7 units and epoxy units" (hereinafter referred to as "second component (B)"), the ethylene units of which are 30 to 99.5
It is an ethylene copolymer containing % by weight.

This ethylene copolymer (B) is a copolymer obtained by copolymerizing at least ethylene and the following seven monomers to constitute the second component CB), and a multicomponent of these and other monomers. Examples include saponified products obtained by saponifying copolymers of ethylene and vinyl esters (in particular, vinyl acetate).

Examples of this monomer include an organic compound having an epoxy group represented by the following general formula [formula (1) to formula III], hydroxyalkyl (meth)acrylate (the number of carbon atoms in the alkyl group is usually 1 to 25), α-Alkenyl alcohols having 3 to 25 carbon atoms and 2 to 25 carbon atoms
α-amines and primary or secondary aminoalkyl (meth)acrylates (the number of carbon atoms in the alkyl group is usually 1 to 1)
25 items) can be given.

(CH2)n -C-0-R4(II) Representative examples of monomers represented by formula (I) or formula III include butenecarboxylic acid monoglycidyl ester, glycidyl methacrylate, glycidyl acrylate, and methylglycidyl acrylate. , methyl glycidyl methacrylate, itaconic acid glycidyl ester, 7,8-epoxy-1-octyl methacrylate, itaconic acid methyl glycidyl ester, 7,8-epoxy-1-octyl alcohol ether, vinyl glycidyl ether, allyl glycidyl ether and meth Examples include lyl glycidyl ether.

Typical examples of monomers having hydroxyl units or amine units include hydroxymethyl (meth)acrylate, hydroxymethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and hydroxyhexyl (meth)acrylate. ) acrylate, allyl alcohol,
Mention may be made of allyl amines and amine ethyl (meth)acrylates.

Moreover, examples of other monomers include the unsaturated carboxylic acid esters and vinyl esters.

The ethylene unit in this ethylene copolymer (B) is 30
-99.5% by weight, preferably 30-99.0% by weight, particularly preferably 35-99.0% by weight. Further, the proportion of hydroxyl units, amide 7 units and epoxy units in the copolymer is 0.1 to 70% by weight for the same reason as in the case of the ethylene copolymer (A), and is 0.5% by weight. The content is preferably from 70% by weight, particularly from 0.5 to 60% by weight. Furthermore, when using a multicomponent copolymer containing the unsaturated carboxylic acid ester and/or vinyl ester, the total amount thereof is generally at most 7
0% by weight, particularly preferably 60% by weight or less.

Melt index (JIS K-721) of the ethylene copolymer (A) and ethylene copolymer (B)
0, measured under condition 4, hereinafter rM, 1. J) is generally 0.001 to 1000 g/10 min, preferably 0.05 to 500 g/'no min, especially L
1 to 500 gllO min is suitable. M, 1. is 0
．． If these ethylene-based copolymers are used for less than 710 minutes, it is not only difficult to mix these copolymers uniformly, but also the moldability is poor.

Among these ethylene copolymers, when produced by copolymerization method, the amount is usually 500 to 2500 kg/c.
ethylene and the second component (A) or the second component (B) or these and other components in the presence of a fast chain transfer agent (e.g. an organic peroxide) at a temperature of 120-260° C. under high pressure of The ethylene copolymer (A) can be obtained by copolymerizing with ethylene copolymer (A), and its production method is well known. The method and the method for producing the ethylene copolymer (B) by saponification are also well known methods.

(C) Production of mixture (1) Mixing ratio In producing the mixture of the present invention, ethylene copolymer (A) and ethylene copolymer (B
) Ethylene copolymer (A) in the total amount (total)
The mixing ratio of the ethylene copolymer ('3) is 1 to 99% by weight [that is, the mixing ratio of the ethylene copolymer ('3) is 99 to 1% by weight],
5-==95% by weight is desirable, particularly 10-90% by weight. Even if the mixing ratio of ethylene copolymer (A) in the total amount of ethylene copolymer (A) and ethylene copolymer (B) is less than 1% by weight or more than 99% by weight, When the mixture is crosslinked by the method described later, the crosslinking is insufficient, and the adhesion with the conductive metal layer described later is poor.

(2) Mixing method This mixture can be produced by uniformly mixing the ethylene copolymer (A) and the ethylene copolymer (B). The mixing method may be tri-blending using a Henschel mixer, which is commonly used in the field of olefin polymers, or melt-kneading using a mixer such as a Banbury, extruder, or roll mill. can be given. At this time, a more uniform mixture can be obtained by triblending in advance and melt-kneading the resulting mixture. When melt-kneading, it is necessary that the ethylene copolymer (A) and the ethylene copolymer (B) do not substantially undergo a crosslinking reaction (
If the resulting mixture is crosslinked, it will not only deteriorate the moldability when molding the resulting mixture as described below, but also cause a decrease in the shape of the intended molded product and the heat resistance when crosslinking the molded product. unfavorable for the sake of becoming). For this reason, the melt-kneading temperature depends on the type and viscosity of the ethylene polymer used, but is preferably room temperature (20°C) to 150°C, and preferably 140°C or lower.

As a guideline for this "substantially no crosslinking", "residual aroma with a diameter of 0.1 micron or more after extraction treatment in boiling torunin for 3 hours" (hereinafter referred to as "extracted residual aroma") is generally 15% by weight. It is preferably at most 10% by weight, most preferably at most 5% by weight.

In producing this mixture, stabilizers against oxygen, light (ultraviolet light) and heat, metal deterioration inhibitors, flame retardants, electrical property improvers and antistatic agents commonly used in the field of olefinic polymers are used. Additives such as lubricants, weight improvers, and tack improvers may be added to the extent that the properties (physical properties) of the thin-walled material of the present invention are not impaired. Furthermore, by adding a crosslinking accelerator such as a primary to tertiary monoamine, p-toluenesulfonic acid diamine, and a quaternary ammonium salt, the ethylene copolymer (A) and the ethylene copolymer can be combined as described above. (B)
The amount added is usually at most 5.0 parts by weight (preferably 0.01 to 3.0 parts by weight, 1 part) per 100 parts by weight of these resins. . Furthermore, by adding insulating ceramics such as alumina and silicon nitride, CM! ! It is also possible to improve the affinity. Furthermore, the function of the present invention can be further improved by filling with inorganic powder, glass fiber, glass beads, etc.

(D) Manufacture of thin products The mixture obtained as described above is 1 inch thick to be produced into thin products. T-Guy film, which is commonly used in the field of thermoplastic resins, is widely used in the production of films by the inflation method. A thin-walled product can be obtained by extruding it into a film or sheet using a conventional extruder. At this time, the extrusion temperature was 25
The temperature is below 0°C. However, when extruded at a temperature exceeding 250°C, the ethylene copolymer (A) and the ethylene copolymer (B
) is partially crosslinked and small lumps of gel-like material are generated, making it impossible to obtain a uniform extruded product. For these reasons, the extrusion temperature is in the same temperature range as in the case of the melt crosslinking described above, regardless of whether a crosslinking accelerator is added (blended) or not.

In any of the above cases, after manufacturing the thin-walled objects, the thin-walled objects with good transparency are made by rapidly cooling them in a water-cooling roll or a water bath to prevent adhesion between the thin-walled objects or between the thin-walled objects and a take-up roll. can get. The thickness of the thin-walled product thus obtained is between 3 microns and 5 mm, particularly preferably between 5 microns and 3 mm.

It is important that the thin-walled product obtained in this manner is not crosslinked in terms of wood quality. That is, the extracted residual aroma is preferably 15% by weight or less, preferably 10% by weight or less, and most preferably 5% by weight or less, as described above.

(E) Conductive Metal Layer Methods for obtaining the conductive metal layer of the present invention include a method using a metal foil, a method of depositing metal, a method of electroless plating, and an electroless plating method and an electrolytic plating method as described below. One method is to use them together.

(1) Types of metals Metals include metals such as aluminum, gold, silver, copper, and platinum, and those containing these as the main component (50% by weight).
Above) alloys can be mentioned, but copper is generally preferred because of its good electrical conductivity.

(2) Foil The thickness of this metal foil is usually 5 to 500 microns, and 1
0 to 300 microns is preferable, especially 1
5 to 100 microns is preferred. Among the metals, electrolytic copper foil with a thickness of 15 to 50 microns is preferably used.

(3) Vapor deposition As a method for vapor depositing the metal, commonly used vacuum heating vapor deposition such as resistance heating, electron beam heating, induction heating, or thermal radiation heating, or sputtering can be applied. Particularly for fine circuits, platinum and gold are often used, and when forming a circuit by etching after forming a thin film, copper, aluminum, and alloys containing these as main components are preferably used.

The thickness of the deposited conductive thin film can be freely selected depending on the conditions of the equipment used, but it is usually about 100 mm (
angstroms) to 100 microns, preferably 1000 s to 20 microns.

Furthermore, copper, nickel,
It is also possible to electroplate a metal such as gold to protect the surface and prevent corrosion, or to apply solder on the conductive path through a solder bath.

A so-called full additive method is also possible in which a circuit is formed by vapor deposition carried out in the present invention on the surfaces of the metal or alloy plate and ceramic layer and on the inner surfaces of the through holes.

In addition, the conductive metal layer can be manufactured by using an electroless plating method or a combination of an electroless plating method and an electrolytic plating method, which are described in detail in Japanese Patent Application No. 80-Ei899.

(F) Printed circuit board The printed circuit board to be laminated used in the present invention may be composed of the thin material obtained as described above and a conductive metal layer, but it may also be composed of these and other substances described below. good.

(1) Other substances Other substances include metal or alloy foil of the conductive metal layer, glass fiber cloth or nonwoven fabric, aramid fiber nonwoven fabric, and heat-resistant thermoplastic resin such as polyamide-imide, polyimide, and polyester. I can give you a film. The thickness of the metal or alloy foil is usually 5 to 200 microns, with 15 to 100 microns being particularly preferred. Also # of glass! The thickness of the fibrous or non-woven fabric is from 5 microns to 2III11, especially 2
1. The thickness of the heat-resistant thermoplastic resin film is preferably 3 microns to 0.5 mm. Omm, especially 10 microns to 20 microns
0 micron is preferred.

(2) Manufacture of printed circuit board The printed circuit board of the present invention is produced by heating and pressurizing the above-mentioned thin material as described below, and applying the above-mentioned "
The conductive metal layer may be provided by any one of vapor deposition, electroless plating, or a combination of electroless plating and electrolytic plating (hereinafter referred to as "Method (A) J"). Alternatively, the metal foil and the thin material may be subjected to heating and pressure treatment.

Alternatively, at least one other substance may be placed on one or both sides of the thin-walled object, and these materials may be heated and pressurized, and a conductive metal layer may be provided on one side of the resulting crosslinked object by method (A). Place a metal foil on one side of an object and another substance on the other side, or place a metal foil and another substance on one side of a thin object (with the metal foil on the surface) and another substance on the other side, and heat φ. Pressure treatment may also be applied.

(3) Heat/pressure treatment The thin-walled product obtained as described above exhibits the same behavior as a normal thin-walled product because crosslinking has hardly progressed. In order to impart heat resistance to the thin-walled material, it is important to heat and pressurize it in the range of 100 to 400°C. Heating temperature is 1
10-20 minutes in the range of 00-160℃, teo-24
By heating and pressurizing for 0.5 to 10 minutes in the range of 0℃ and 0.1 to 5 minutes in the range of 240 to 400℃, a crosslinking reaction (condensation reaction) occurs within the resin, improving adhesiveness and heat resistance. performance is significantly improved. The pressurization conditions are generally 0.1 Kg/crn' (gauge pressure) or higher, and 1-
100 Kg/crn' is desirable, especially 2~
20Kg/crn' is preferred.

Furthermore, in order to obtain uniform adhesion, a method of applying pressure with a slight load under vacuum and reduced pressure is also used.

Since the thin-walled article obtained by the present invention exhibits thermocompression adhesion (adhesiveness) at a temperature of 100°C or higher, the effects of the present invention can be obtained by bonding the metal layer or the metal layer and other substances at the same time as the crosslinking treatment. It spreads further. That is, although the mixture of ethylene copolymer (A) and ethylene copolymer (B) exhibits thermoplasticity at a temperature of 250°C or lower, the mixture is heated to 100°C or higher and subjected to φ pressure treatment. This causes a crosslinking reaction and at the same time exhibits adhesive properties.

When air is involved between a metal foil or other material and a thin object, it is necessary to use a hot press, hot roll, etc. to bond the thin material. Even if the heating temperature is 300°C or lower, a product with sufficient adhesiveness can be obtained, but if heat resistance is required, it is preferable to press the adhesive at as high a temperature as possible (usually 200 to 300°C).

The extracted residual aroma of the thin-walled product heated and pressurized in this manner is usually at least 60%, preferably 70% or more, and particularly preferably 75% or less.

(G) Metal-based multilayer printed circuit board The metal-based multilayer printed circuit board of the present invention is obtained by laminating the above-described flexible substrate on a metal base substrate. A representative metal-based multilayer printed circuit board of the present invention will be specifically explained with reference to the drawings. FIG. 1 is a partially enlarged sectional view of the metal-based multilayer printed circuit board. As shown in this drawing, parts that require heat dissipation performance, such as ICs or semiconductors, are mounted on the circuit of an aluminum base board, and other parts are mounted on a laminate of the flexible printed circuit board of the present invention and a conductive metal layer. may be stacked to form a multilayer structure. Of course, it may be multi-layered after implementation, but
Due to the heat resistance problem of the IC1 semiconductor, it is safer to open the mounting area in advance, create multiple layers, and finally mount the IC and other components.

The metal base substrate used in the present invention is, for example, a plate of a metal such as aluminum or copper or an alloy mainly composed of these (the thickness is generally 0.1 to 30 mm, preferably 0.3 to 10 mm, preferably is 0.5~5 m11
1), and it is also possible to use an aluminum plate whose surface has been subjected to a surface treatment such as alumite processing. A thin cross-linked product or an epoxy resin layer of the present invention is used as an insulating layer between this metal or alloy plate and a conductive metal layer serving as a circuit, and a thin cross-linked product of the present invention is used as an insulating layer, Moreover, any substrate with improved heat dissipation properties as described in Japanese Patent Application No. 81-20267 and the like may be used as the adhesive layer. Further, multilayering can be achieved by forming a circuit on the printed circuit board of the present invention and the conductive metal layer, and then bonding them by thermocompression by a roll method or a press method. In order to fill the gaps between circuits and improve the adhesion and heat resistance between multiple layers, patent application Sho Eta-207778
The thin coverlay described in the specification or the ethylene copolymer (A) of the present invention and the ethylene copolymer (
A crosslinked mixture with B) may also be used.

FIG. 1 is a partially enlarged sectional view of a typical metal-based multilayer printed circuit board of the present invention. In this drawing, 1 is a metal plate (metal base), and 2 is a thin crosslinked product or an epoxy resin layer of the present invention. Further, 3 is a conductive metal layer, and 4 is a thin crosslinked material of the present invention. moreover,
5 is a conductive metal layer whose side surface is plated with through holes, 6 is a component such as an IC or semiconductor, and 7
is the lead wire of the component 6.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the Examples and Comparative Examples, the humidity resistance was observed after 1000 hours at a temperature of 120°C, a pressure of 2 atmospheres, and a humidity of 10% (1%).The heat cycle resistance was measured up to 125°C. It was heated, left at this temperature for 30 minutes, then cooled to -55°C, left at this temperature for 30 minutes, and this heating and cooling process was repeated 100 times, and the state of peeling of the IC multilayer substrate was observed. Furthermore, heat shock resistance was determined by heating to 150°C, leaving at this temperature for 5 minutes, and then -
Cool to 80°C and leave at this temperature for 5 minutes,
This heating and cooling process (heating and cooling rates were both 100°0/2 seconds) was repeated 10 times, and changes in the appearance of the multilayer were observed.

In addition, each mixture used in the examples was manufactured as follows.

M, 1. Ethylene-acrylic acid copolymer with a density of 300 g/10 min (density 0.954 g/cm
', acrylic acid copolymerization ratio 20% by weight, hereinafter rEAA
J) and an ethylene-vinyl acetate copolymer with a vinyl acetate copolymerization ratio of 28% by weight (saponification degree 87.5%, M,
I.

75g/10min, density 0J51 g/cm',
(hereinafter referred to as "saponified material") [mixing ratio 50:50 (weight ratio), hereinafter referred to as "mixture (1)"), ethylene-methacrylic acid co-acid in which M and L are 200 g/10 min. Polymer (density 0.950 g
/ cm', methacrylic acid copolymerization ratio 25
% by weight) and the above saponification degree (mixing ratio 50
: 50 (weight ratio), hereinafter referred to as "mixture (■)")
, M', 1. Ethylene-ethyl acrylate-maleic anhydride ternary copolymer (ethyl acrylate copolymerization ratio 30.7% by weight, maleic anhydride copolymerization ratio 1.7% by weight) with a temperature of 212 g/l (1 min) Terpolymer of ethylene-methyl methacrylate-hydroxymethaflerate (1.
Copolymerization ratio of methyl methacrylate: 20.7i%,
hydroxymethacrylate (copolymerization ratio 11.7% by weight) [mixing ratio 50:50 (weight ratio), hereinafter referred to as [mixture (III) J]] and M
, 1. terpolymer of ethylene-methyl methacrylate-maleic anhydride (copolymerization ratio of methyl methacrylate: 20.5% by weight, copolymerization ratio of maleic anhydride: 3.1% by weight) and ethylene. - Methyl methacrylate - glycidyl methacrylate terpolymer (copolymerization ratio of methyl methacrylate
18.8% by weight, copolymerization ratio of glycidyl methacrylate 12.7% by weight) [Mixing ratio: 30:
70 (weight ratio)], hereinafter referred to as "mixture (■)"). These mixtures were prepared by tri-blending each copolymer or terpolymer for 5 minutes using a Henschel mixer. Manufactured.

Examples 1 to 6, Comparative Examples 1 to 3 Mixtures (I) to IV) obtained as described above
In addition, EAA and saponified materials were each processed to a thickness of 100 microns using an extruder equipped with a T-die (40 mm diameter, 300 m die width, 85 rotations/min) under the Schilling temperature conditions shown in Table 1. A film was formed. The extracted residual aroma of the obtained film was measured. In both cases it was 0%.

Table 1 Each of the films thus obtained was used as a metal plate, an aluminum plate (thickness 1.5 mm, hereinafter referred to as "rAl plate") or a copper plate (thickness 1.0 mm, hereinafter referred to as "Cu plate").
) (types are shown in Table 2) and copper foil (thickness 3
5 microns) and heated at 20K at a temperature of 260℃.
A metal substrate was prepared by heating and applying pressure for 10 minutes under a pressure of "g/crn". This substrate was etched in a conventional manner to form a predetermined circuit.

In addition, using the same method as above, a second layer was added as an insulating layer using the same copper foil as above.
A substrate for lamination was prepared by laminating the uncrosslinked film (1) whose type of mixture is shown in the table and heating and pressurizing it under the same conditions as above. Furthermore, a circuit was formed by etching in the same manner as described above6.Furthermore, the semiconductor device shown in FIG. 1 was punched out in advance. The obtained various lamination substrates and the same uncrosslinked film as above were used as a metal substrate and film (2).
(as an adhesive layer), a lamination substrate, Fichem (2) (as an adhesive layer) and/or a lamination substrate, and after placing an uncrosslinked film as an intermediate adhesive layer and accurately aligning the Heat and pressurize in the same manner as
As shown in the figure, a multilayer board was created in which three layers of multilayer boards were stacked on a metal board. The obtained multilayer substrate was tested for moisture resistance, heat cycle resistance, and heat shock resistance. The results obtained are shown in Table 2.

(Left below) From the results of the above Examples and Comparative Examples, it is clear that the metal-based multilayer print of the present invention is not only capable of multilayering on metal substrates, which was previously considered impossible, but also has excellent moisture resistance and It is clear that a multilayer substrate with excellent heat dissipation properties that can sufficiently withstand temperature changes is possible.

Bonus (7): The metal-based single-phase printed circuit board of the present invention, including its manufacturing method, exhibits the following effects.

(1) Since the metal substrate is the base, the heat dissipation effect is high.

Therefore, it is possible to mount high-power components, semiconductors, ICs, and other heat-generating components.

(2) It not only has excellent heat resistance but also good heat shock resistance.

(3) Multilayer substrates can be easily manufactured by heat and pressure treatment.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged sectional view of the metal-based multilayer printed circuit board of the present invention. 1...Metal plate 2...Insulating layer 3
... Conductive metal layer 4 ... Insulating/adhesive layer 5 ... Through hole 6 ... Parts such as semiconductors and ICs 7 ...
Lead

Claims (1)

[Claims] The metal-based multilayer printed circuit board (A) consists of at least ethylene units and at least one type of unit selected from the group consisting of carboxylic acid units, dicarboxylic acid units, their anhydride units, and half ester units, and the content of ethylene units is 30-99.5% by weight of an ethylene-based copolymer and (B) at least ethylene units and at least one unit selected from the group consisting of hydroxyl units, amino units and epoxy units; and the content of ethylene units is 30 to 99.5
A flexible printed circuit board formed by laminating at least a thin material having a thickness of 3 microns to 5 mm and a conductive metal layer, which has at least a crosslinked product of a mixture of 99 to 1% by weight of an ethylene copolymer, is made of metal. A metal-based multilayer printed circuit board that is laminated onto a base printed circuit board.