JPS61217236A - Printed substrate - 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 uses a ceramic substrate as a substrate, which not only has good heat resistance but also has good heat dissipation properties and has excellent dimensional stability due to heat. Regarding printed circuit boards. More specifically, (A) ceramic layer, (B) (1) ethylene-
A print formed by sequentially laminating a crosslinked layer of a mixture of an acrylic acid copolymer and/or an ethylene-methacrylic acid copolymer and (2) a saponified product of an ethylene-vinyl acetate copolymer, and (C) a conductive metal layer. The present invention relates to a substrate, and aims to provide a pudding I/substrate using a ceramic plate as a substrate, which not only has good heat resistance but also good heat dissipation and excellent dimensional stability due to heat. It is something.

With the development of the electronics industry, electronic components have become smaller and the use of ceramic printed circuit boards, which have both high density and high density, has become popular. Ceramic boards used as printed circuit boards not only have good electrical properties but also have thermal stability, and take advantage of their small dimensional change in the thickness direction to create through-hole printed circuit boards (multilayer boards) on both sides. It is used as. Conventionally, alumina and the like have been used as ceramic materials for ceramic plates.

Conventionally, laminating copper foil on a ceramic plate has rarely been done. The reason for this is that there is no adhesive that has good adhesion to either ceramic materials or copper. Some attempts have been made to use epoxy resins as adhesives, but they have not been put to practical use because their adhesive properties are not necessarily satisfactory. Furthermore, even if an epoxy resin is used to bond the ceramic plate and the copper foil, it is expected that the circuit will break due to the difference in thermal expansion coefficient between the two.

Based on these facts, in order to manufacture ceramic printed circuit boards, tungsten, molysidene,
After printing and drying a conductive paste mainly composed of powder of a metal with a high melting point such as manganese and an insulating paste mainly composed of powder of ceramics (for example, alumina), a weak reduction is applied to prevent the metal from becoming mellow. A wet ceramic multilayer printed circuit board obtained by firing in a static atmosphere and a fired ceramic board are combined with Pase I, which is mainly composed of conductive powder such as silver, palladium, or platinum, and glass as an insulator. There is a dry ceramic multilayer printed circuit board that is repeatedly printed and fired. For miniaturization and high density, wet ceramic multilayer wiring boards are sintered.
Heat shrinkage of 0 to 20% occurs, causing problems such as wire breakage.

In addition, as a printed circuit board that takes advantage of its heat dissipation properties, there is a printed circuit board that uses ceramics on a metal plate as an insulating substrate by thermal spraying using plasma flame spraying, arc flame spraying, or the like.

However, ceramic substrates manufactured by such conventional methods have the following drawbacks.

Solvents in conductive and insulating pastes that are repeatedly printed on ceramic substrates expand the green sheets, causing dimensional changes. That is, the conductor and insulating paste I.
During drying, the volatile solvent causes the green sheet to shrink in volume, and by repeating this, the dimensions of the substrate change. In particular, there are drawbacks that vary depending on the type of circuit. In addition, when printing these conductors, the occurrence of scratches, wire breakage due to adhesion of dust, and pinholes increases, and when screen printing is used, there is a limit to the width of the circuit line, which prevents high density. Furthermore, the printed circuit has many irregularities, which currently reduces the reliability of the connection with the chip when mounting the circuit.

Instead of the conventional etching method for copper-clad laminates, there are additive methods that apply plastic plating technology to directly draw circuits on resin boards by electroless plating, and substructive methods that combine this plating and etching methods. law has come into use. The reason why this additive method has become popular is that it is an effective method for simultaneously forming through-holes and pattern plating for high-volume, low-mix resin laminates. The performance has been improved and it is now possible to obtain highly fine lines. Recently, a resistless method has also been developed in which ultraviolet rays are directly applied to a photoreaction catalyst mixed in the adhesive layer through a photomask to precipitate metal nuclei and electroless plating is performed.

However, the conventional paper-phenolic resin, glass-epoxy resin, and polyimide resin substrates used in these additive methods do not have good adhesion to the plating film, resulting in blistering, peeling, and thickening. When thermal stress is applied due to the large coefficient of thermal expansion in the horizontal direction,
In particular, cracks often occur in the plated parts of fine patterns. Furthermore, when drilling holes in multilayer boards, smearing occurs, which prevents connection with plating and reduces connection reliability. Moreover, the surface of thermally sprayed ceramics is markedly uneven, and the ceramic insulating layer is porous, making it impossible to bond with metal layers such as plating.
The circuits were simply formed using conductive adhesive or the like on metal bases or ceramic sprayed substrates. For these reasons, there is a demand for the development of a method for forming a circuit on a ceramic sprayed substrate by direct plating, vacuum deposition, or the like.

Ming tries to. 1 In view of the above, the present invention provides a printed circuit board in which ceramics are sprayed on a metal plate base, which does not have these drawbacks, takes advantage of the heat dissipation characteristic of conventional ceramic substrates, and improves the lack of strength, which is a disadvantage of ceramic substrates. It is to obtain.

According to the present invention, the above-mentioned problems are solved by: (A) ceramic layer; (B) (1) ethylene-acrylic acid copolymer and/or ethylene-methacrylic acid copolymer; (2) [Ethylene-drunken vinyl copolymer] [hereinafter referred to as "copolymer (2)"] and a saponified product of 1. The crosslinked material layers are sequentially laminated, and the thickness of the ceramic layer is
100 mm to 10 mm, and the crosslinked product contains at least 80% by weight of a residue having a diameter of 0.1 micron or more after extraction treatment with boiling toluene for 3 hours, and the crosslinked product contains at least 80% by weight of a residue having a diameter of 0.1 micron or more after extraction with boiling toluene for 3 hours. The ratio is 20 to 80 weight is loog or 2
00 microns, and this layer can be solved by a printed circuit board formed by any of the following methods: metal vapor deposition, electroless plating, or a combination of electroless plating and electrolytic plating. can.

(A) Ceramic Layer The ceramic layer used in the present invention can be manufactured by firing to form a plate or by forming a thin film on the surface of a metal plate.

Methods for forming thin films include chemical vapor deposition (CVO), which uses chemical reactions, and film deposition methods, which use physical means, such as vacuum evaporation, sputtering, and thermal spraying. Among these methods, the vacuum evaporation method is
This is a method of depositing a substance under a high vacuum, usually 10-5 Torr or less, and is performed by resistance heating, high frequency heating, electron impact, laser heating, etc. Furthermore, the thermal spraying method can be applied using a commonly used method, and a high heat source (
For example, this method uses plasma (plasma) to melt high-melting ceramics and simultaneously sprays the material onto the surface of the material at high speed to coat the material.

For example, 1. When argon, helium, hydrogen, nitrogen, etc. are used as the gas for plasma generation, the flame can reach an extremely high temperature of about 1500°C. Other methods include flame spraying and arc spraying using oxygen-acetylene.
Particles fly at high speeds around the speed of sound, forming a dense coating of ceraminx on the surface of the metal plate. With flame spraying it is possible to reach temperatures of about 2400°C, and with arc spraying it is possible to reach temperatures of about 5000°C. This plasma can be preferably used because 1) the plasma flame is a neutral flame, so the oxidation-reduction force is weak, and the thermal spray material (ceramic material) is less likely to change in quality due to oxidation or reduction.

In this method, 2
It is possible to use a gun that matches the thickness and shape of the object up to a 00KW thermal spray gun.

In addition, the sintering method varies depending on the particle size, particle size distribution, agglomeration state, impurity, etc. of the ceramics that are the starting materials, as well as the sintering conditions such as the forming method, sintering temperature, time, and atmosphere. A sintered product is obtained. This sintering method also includes reaction sintering method, pressure sintering method, (HP method, HI method)
P method), pressureless sintering method, gas pressure sintering method, etc. Furthermore, recently, injection molding methods have become popular in order to promote premature birth. In this method, ceramic powder and an organic binder are generally mixed in advance, the resulting mixture is used to make a primary molded product using an injection molding machine, and the product is made into a product through a degreasing process and a main sintering process.

The methods for forming and sintering the thin film are industrially practiced and widely known.

Types of ceramics include alumina (A text 203)
, silicon nitride (Si3N4), silica (Si02
), titanium nitride (TiN), titanium carbide (Tie)
, zirconium oxide (zirconia, ZrO2),
AM2 03-5i02 series (mullite porcelain) Z
rO2a 5i02, beryllum oxide (Bed),
Magnesium oxide (magnesia, Mg0), BaTiO
3,5iTi03, boron nitride (BN) and boron carbide (84G). Among these ceramics, alumina and silicon nitride are preferred. Above all, alumina is relatively inexpensive.

It can be preferably used because it not only has excellent heat resistance, thermal conductivity, mechanical strength, impact resistance, electrical insulation and chemical durability, but also is easy to process.

The thickness of the ceramic substrate varies depending on the method of forming the thin film and the method of firing. In the method of forming a thin film,
Generally 100A' to 0.1mm, especially 1
Preferably from microns to 100 microns. In addition, in the firing method, the thickness is usually 50 microns to 10 mm, preferably 0.1 mm to 1.5 mm.

(B) Mixture (1) Ethylene-acrylic acid copolymer and ethylene-
The methacrylic acid copolymers and/or the ethylene-acrylic acid copolymers used to produce the mixtures of the invention are furthermore
Methacrylic acid copolymer is produced by combining ethylene and acrylic acid or ethylene and methacrylic acid at high pressure (generally 50 kg/
cm' or more, preferably 100 kg/crn' or more4
-) in the presence of a free radical generator (usually an organic peroxide). The physical properties of each of these are well known.

The copolymerization ratio of acrylic acid or methacrylic acid in these copolymers is 1 to 50% by weight, preferably 5 to 50% by weight. If the copolymerization ratio of acrylic acid or methacrylic acid in these copolymers is less than 1% by weight, a uniformly thin product cannot be obtained. On the other hand, if it exceeds 50% by weight, the softening point will be too low, making handling and transportation inconvenient.

(2) Saponified product of ethylene-vinyl acetate copolymer,
The saponified product of ethylene-vinyl acetate copolymer used to produce the mixture of the present invention is obtained by saponifying (hydrolyzing) the ethylene-vinyl acetate copolymer. Hydrolysis is generally carried out using caustic soda in methyl alcohol. In producing the saponified product of the present invention, it is usually desirable to have a hydrolysis rate of 90% or more. The raw material ethylene-vinyl acetate copolymer is obtained by copolymerizing ethylene and vinyl acetate in the same manner as the ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer described above. be. The copolymerization ratio of vinyl acetate in this ethylene-vinyl acetate copolymer is generally 1 to 60% by weight, particularly preferably 5 to 60% by weight. If the copolymerization ratio of vinyl acetate in this copolymer is less than 1% by weight, a uniformly thin product cannot be obtained. - On the other hand, if it exceeds 60% by weight, the softening point decreases and handling at room temperature becomes difficult.

Saponified products of these ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, and ethylene-vinyl acetate copolymers are industrially produced and used in a wide variety of fields, and we will discuss their manufacturing methods. is also well known.

(3) Mixing ratio The mixing ratio of the ethylene-acrylic acid copolymer and/or ethylene-methacrylic acid copolymer in the mixture of the present invention is 20 to 80% by weight (i.e., ethylene-acetic acid copolymer). The mixing ratio of vinyl copolymer is 80 to 20% by weight.
), preferably 25 to 75% by weight, particularly 30 to 7% by weight
0 double star% is preferred. If the proportion of the ethylene-acrylic acid copolymer and/or ethylene-methacrylic acid copolymer in these mixtures is less than 20% by weight,
Since the number of carboxyl groups (-COO) I) is smaller than the hydroxyl groups (-oH), hydroxyl groups that do not contribute to the condensation reaction remain, resulting in poor heat resistance. on the other hand,
If it exceeds 80% by weight, on the contrary, there are too many carboxyl groups contributing to the synthesis reaction, so that unreacted groups remain and heat resistance and temperature resistance are not improved, which is not desirable.

(4) Mixing method To produce the mixture of the present invention, the following ethylene-acrylic acid copolymer and/or ethylene-methacrylic acid copolymer and the saponified product of ethylene-vinyl acetate copolymer are uniformly mixed. This can be achieved by letting

As a mixing method, tri-blending may be performed using a mixer such as a Henschel mixer, which is commonly used in the field of olefin polymers, or a mixer such as a Banbury mixer, kneader, roll mill, and screw extruder. It can be obtained by melt-kneading using. At this time, a homogeneous mixture can be produced by triblending in advance and melting and kneading the resulting mixture. In addition, melting #1
．． Ethylene-acrylic acid and/or used in kneading
Alternatively, the carboxylic acid group (-〇〇〇〇) possessed by the ethylene-methacrylic acid copolymer and the hydroxyl group (-OH) possessed by the saponified ethylene-vinyl acetate copolymer undergo a woody crosslinking reaction (synthesis reaction). First, it is important that fish eyes do not occur (slight crosslinking may be allowed). From this, the melting temperature is the temperature at which the saponified products of these ethylene-acrylic acid copolymers and/or ethylene-methacrylic acid copolymers and ethylene-vinyl acetate copolymers melt, but the crosslinking reaction does not occur. There is no temperature. The melting temperature varies depending on whether or not a crosslinking accelerator is added in the latter stage, as well as their type and amount added. However, when no crosslinking accelerator is added, it is usually 180'C or less, especially 10
0 to 150°C is preferred. If the temperature is less than 100°C, these resins will not be completely melted, which is not preferable. On the other hand, when a crosslinking accelerator is added (blended), the temperature is generally 140°C or lower, and the temperature is 100°C or higher.

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, processability improvers, and tackiness improvers may be added to the extent that they do not impair the characteristics (physical properties) of the thin-walled product of the present invention.

Furthermore, by adding crosslinking accelerators such as epoxy compounds, P-)luenesulfonic acid and AM-isopropoxide, ethylene-acrylic acid copolymer and/or ethylene-methacrylic acid copolymer and ethylene - The crosslinking described below with the saponified vinyl acetate copolymer can be further completed. The amount added is usually at most 0.1 parts by weight (preferably 0.01 to 0.05 parts by weight) per 100 parts by weight of these resins. Furthermore, it is also possible to improve the insulation properties by adding ceramics having insulation properties such as alumina and silicon nitride. Furthermore, the function of the present invention can be enhanced by filling the layer with inorganic powder, glass weave, glass beads, etc.

(C) Production of thin-walled products The mixture obtained as described above-1- is produced into thin-walled products as described below. When using a thin material in the form of a film or sheet, a T-die film, which is commonly used in the field of thermoplastic resins, and an extruder, which is widely used when producing films by the inflation method, are used to make the film 1. A thin-walled product can be obtained by extruding it into a shape or a sheet. At this time, the extrusion temperature is 250°C or less. Karini, 250
When extruded above °C, some of the saponified products of ethylene-acrylic acid copolymer and/or ethylene-methacrylic acid copolymer and ethylene-vinyl acetate copolymer crosslink,
Due to the generation of small gel-like particles, a uniform extrudate cannot be obtained. For these reasons, the extrusion temperature is in the same temperature range as in the case of melt-kneading 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 0.2 and 1000 microns, preferably between 0.2 and 500 microns, particularly preferably between 0.2 and 200 microns.

It is important that neither the mixtures described above nor the thin-walled products described above are crosslinked. In other words, "3 with boiling toluene"
After time extraction treatment, the amount of residual aroma with a diameter of 0.1 micron or more (hereinafter referred to as "extracted residual aroma") is generally at most 15% by weight, preferably 10% by weight or less, particularly 5% by weight or less.
It is preferably less than % by weight. If the extracted residual aroma of the mixture and thin-walled product exceeds 15%, the moldability will decrease during the production of the mixture and thin-walled product, resulting in a uniform thin-walled product (molded product).
is not obtained.

In manufacturing the printed circuit board of the present invention, the above ceramic layer and the thin material are placed in this order, and heated and pressurized as described later to form copolymer (1) and copolymer (1), which are the mixed components of the thin material. A laminate with good adhesiveness can be obtained while the saponified product of 2) is crosslinked.

(D) 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. 1130 minutes for 20 to 30 minutes when the heating temperature is in the range of 100 to 180°C.
10-20 minutes at ~240°C, 240-400°C
℃ range, by heating and pressurizing for 0.1 to 10 minutes, a crosslinking reaction (condensation reaction) occurs within the resin, and the adhesiveness and heat resistance are significantly improved. As for the pressurizing conditions,
Generally, it is 5Kg/crn' (gauge pressure) or more, h,
10 to 200 Kg/cm' is desirable, particularly 10 to 100 Kg/cm'. 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 further enhanced by bonding it to metal at the same time as the crosslinking treatment. That is, a mixture of an ethylene-acrylic acid copolymer and/or an ethylene-methacrylic acid copolymer and a saponified product of an ethylene-vinyl acetate copolymer exhibits thermoplasticity at a temperature of 250°C or less; A crosslinking reaction is carried out by heating and pressurizing to 100'0 or more,
At the same time, it exhibits adhesive properties.

To produce a laminate using this method, a thin piece of the uncrosslinked mixture is placed on the surface of the ceramic layer and heated and pressurized to the temperature range mentioned above. If air is to be trapped between the protective surface and the thin material, it is necessary to use a heat press, heat roll, etc. to bond the material under heat. A product with sufficient adhesive properties can be obtained even if the heating temperature is 300°C or lower, but if heat resistance is required, heating at a temperature as high as possible (usually 200°C to 300°C) is recommended.
00'0) is preferable. A thin-walled product with good heat resistance and adhesiveness can be obtained by heat-compression bonding at a temperature 10° C. to 20° C. higher than the required heat resistance temperature.

The printed circuit board of the present invention can be manufactured by providing a conductive metal layer on the laminate obtained as described above.

(E) Conductive metal layer This conductive metal layer can be obtained by vapor depositing a metal;
Examples include a method of electroless plating and a method of combining electroless plating and electrolytic plating.

(1) Vapor Deposition As a method for vapor depositing the metal, commonly used vacuum heating vapor deposition such as resistance heating, electronic tin heating, induction heating, or thermal radiation heating, or sputtering can be applied. Examples of the metal vapor deposits used include metals such as aluminum, gold, copper, nickel, and platinum, as well as alloys containing these as main components (50% by weight or more) (for example, stainless steel). 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 conductor thin film can be freely selected depending on the conditions of the equipment used, but it is usually 100X (
angstroms) to 100 microns, preferably 100 OX to 20 microns.

Furthermore, copper, nickel,
It is also possible to apply electroplating to 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. Generally, the insulating material used in the fully additive method is one coated with an adhesive on the surface, but the insulating material of the present invention is made of ethylene-acrylic acid copolymer and/or ethylene-methacrylic acid copolymer "Thin material obtained from a mixture consisting of a diluted copolymer and a saponified product of ethylene-vinyl acetate copolymer"
(hereinafter referred to as "rE-E thin material") has excellent adhesion to the deposited material without using an adhesive. Furthermore, it is possible to form conductor circuits by common circuit forming methods, such as cutting E-E thin materials to specified dimensions and drilling holes (punching method, drilling method, and pressing method). Any processing is possible). Next, pattern formation is performed by screen printing with a negative pattern or by masking unnecessary portions with a photosensitive agent. By depositing this masked E-E thin film, a metal deposited film having a specified thickness is formed on the unmasked circuit portion, thereby forming a pattern. Excellent alkali resistance is a necessary condition for long-term immersion in mask printing.

Usually, it is possible to form a layer that serves as both a photosensitizer and an adhesive, which is used in the commonly used full additive method, and then expose this layer to light to make it easy to bond and form a vapor deposited film only on the circuit area. It is being done. but,
The printed wiring board of the present invention does not require the use of these materials, and the directly vapor-deposited metal film layer has good adhesion and adhesion on the surface of the thin E-E material, making it suitable for mass production. Alternatively, it is possible to form a precise circuit by using normal etching without any defects (such as hair formation or pattern breakage). After vapor deposition, corrosion prevention for circuit protection, and even IC
It is also possible to plate the chip with gold, soot, solder, etc. in order to mold the chip.

The printed wiring board of the present invention can use any of the fully additive adhesive printing method, adhesive photography method, and direct method, and is characterized in that the direct method can also be used.

(2) Electroless plating Generally, electroless plating, that is, chemical plating, includes nickel plating, highly corrosion-resistant zinc alloy plating, and copper plating. The thickness is uniform on the surface of
Copper sulfate plating is usually put into practical use because it has excellent adhesion and ductility between the material (substrate) and the plating film, allowing a dense plating film to be obtained. According to this copper sulfate plating, the crystals are fine and the leveling (uniform thickness) is l4
At the same time, a product with stable workability and excellent physical properties can be obtained.

Generally, in copper sulfate plating, copper sulfate and sulfuric acid are used to supply metallic copper into the solution and improve the conductivity and uniform electrodeposition of the solution. Additionally, chloride ions (as a catalyst) and appropriate amounts of brighteners are used. Additionally, polyoxyethylene and polyoxypropylene derivatives may be used to enhance leveling. A typical composition is 5-405-4O copper sulfate (CuSOa, 5H20) in an aqueous solution.
) and further add pH adjusters (buffers) such as caustic soda (NaOH) and ammonium chloride (N
84 CI), etc., and to prevent abnormal precipitation of copper in an aqueous solution, for example, EDTA-2Na (
Sodium salt of ethylenediaminetetraacetic acid) and formalin (HCHO) as a reducing agent are added. Furthermore, copper,
It is also possible to electroplate metals such as nickel or gold to protect the surface and prevent corrosion, or to apply solder on the conductive paths through a solder bath.

This is a so-called full additive method in which a circuit is formed by electroless conductive plating on the surface of the thin-walled object and the inner surface of the through hole by chemical plating carried out in the present invention, and t! A feature of this product is that it does not require an etching process unlike laminates covered with i4 foil. Generally, full
The insulating material used in the additive method has a catalyst added for plating or has an adhesive applied to its surface, but the E-E thin material of the present invention does not contain a catalyst or an adhesive. Excellent adhesion to electroless copper even without the use of agents. Furthermore, it is possible to form a conductor circuit by a general circuit-forming force method, for example, by depositing an E-E thin material with specified dimensions on the surface of a metal or alloy plate that has been sprayed with ceramics. Cut and drill holes (punching method, drilling method, and press processing are all acceptable). Next, pattern formation is performed by screen printing with a negative pattern or by masking unnecessary portions with a photosensitive agent.

This masked E-E thin object is placed in an electroless copper plating solution, and copper plating of a specified thickness is deposited on the unmasked circuit portions to form a pattern. Mask printing and photosensitizers must have excellent alkalinity because they are immersed in electroless plating solution for a long time.

Usually, a layer is formed that serves as both a photosensitive agent and an adhesive, which is used in the commonly used full additive method, and by exposing this layer to light, only the circuit area becomes a layer that is easy to bond and deposit electroless copper plating. things are being done. However, in the printed circuit board of the present invention, there is no need to use these, and the electroless copper plating layer is directly formed on the surface of the E-E thin object with good adhesion and adhesion, making it suitable for mass production. Not only is it possible to form precise circuits using normal etching without any defects (such as hair formation or pattern breakage). After chemical plating, it is also possible to plate gold, soot, solder, etc. for corrosion prevention for circuit protection and for molding IC chips.

The printed circuit board of the present invention can be used with any of the fully additive adhesive printing method, adhesive photography method, and direct method, but the greatest feature is that the direct method can be used.

Hereinafter, the printed circuit board of the present invention, the laminate used for manufacturing this printed circuit board, and the printed circuit board will be explained with reference to the drawings.

FIG. 1 is a partially enlarged cross-sectional view of a representative example of the printed circuit board of the present invention. Moreover, FIG. 2 is a partially enlarged sectional view of a typical example of the laminate used to manufacture this printed circuit board.

In these figures, ■ is a ceramic layer. Moreover, 2 is a crosslinked product of E-E thin material. Furthermore, 3 is a conductive metal layer. The printed circuit board shown in Figure 1 was obtained by the direct method among the fully additive methods, but it could also be obtained by any of the other methods such as adhesive printing, adhesive photography, and vacuum evaporation at the same time. Of course, it is possible to manufacture it.

In manufacturing the printed circuit board of the present invention, there is no need to further use an adhesive commonly used between the ceramic layer and the conductive metal layer, which not only omits the adhesive application step but also No blistering occurs when heated due to volatile substances (for example, organic solvents) contained therein. In addition, during molding and heat-pressing of thin objects, the insulating adhesive resin layer exhibiting thermoplasticity undergoes a crosslinking reaction through these high-temperature heat treatments, resulting in a crosslinked thin object, which offers advantages such as significantly improved flexibility. It is something that you have.

EXAMPLES The present invention will be explained in more detail with reference to examples below.

In addition, in the Examples and Comparative Examples, the heat resistance test was performed using the obtained film as UL 79B (printed wiring board).
7.1 A copper-clad printed circuit board consisting of a ceramic layer with the test pattern shown in Figure 1 was placed in a solder bath of lead/tin -55745 (by weight) held at 220°C and at 300'O. It was evaluated by floating it for 180 seconds in a solder bath having lead/tin-90710 (weight ratio).

Examples 1 to 6, Comparative Examples 1 to 6 Melt flow index (according to JIS K-8780, temperature is 190°C and load is 2.11 (kg
Measured under the following conditions: r%, 1. J) is 300g7
Ethylene-acrylic acid copolymer (density 0.
Obtained by saponifying an ethylene-vinyl acetate copolymer containing 100 parts by weight of 954 g/cm', acrylic acid copolymerization rate of 20% by weight, hereinafter referred to as rEAA J) and a vinyl acetate copolymerization rate of 28% by weight. Saponified material (saponification degree 87.5%, calendar, 1.75 g/10 minutes, density 0.951 g/cm', hereinafter "saponified material")
) 100 ff1 (tri-blend the IT part for 5 minutes using a Henschel mixer to produce a mixture ``IFF'', compound ``(^)'').In addition, a mixture (A) was produced. Instead of the ethylene-acrylic acid copolymer used in the washing, M, T, 200 g/
A mixture [hereinafter referred to as "mixture ( B)" was produced.

The mixture (A) obtained in step 17 and the FAA and saponified material used to produce the mixture (A) were each extruded using an extruder (diameter 4) equipped with a T-die.
A film (thickness: 20 microns) was molded using a die with a diameter of 0 mm, a die width of 30 cm, and a rotation speed of 85 revolutions/min under the conditions shown in Table 1 for the cylinder temperature.

Each film thus obtained was heated at 250°C and
Laminated on the surface of the ceramic plate whose type and thickness are shown in Table 2 as shown in Figure 1 at 20 kg/cm' (gauge pressure) using a heat press machine for 10 minutes each at 00 °C. A laminate was produced. Table 1 shows the properties of the film produced as described in Section 1tii.

Furthermore, Table 2 shows the results of a heat resistance test of the laminates that were bonded (laminated) at the adhesion temperatures shown in Table 2. In Examples 5 and 6, the film obtained in Example 3 was used as the adhesive layer, and in Comparative Example 6, the commonly used epoxy resin (
adhesive) was used. In addition, in the column of ``Base substrate material'' in Table 2, "A'' is low soda alumina (Au203).
Content 89.8% by weight, true density 3.81g/Cm''
, average grain size 0.6 microns), with a thickness of 1.0 mm, obtained by sintering
B” is silicon carbide (α-9iC1 true density 3.22g
/crn', average grain size 2 microns), with a thickness of 0.5 mm. In addition, "C" is boron nitride (BN, density 2
．． The thickness obtained by sintering 27g/Cm', average grain size 3.5 microns) was 1. ．． 2mm BN
11 D 11 refers to the alumina plate of A above bonded with an epoxy adhesive.

In addition, in Comparative Examples 1 to 3, as shown in Table 1,
Gel was generated on the surface of the resulting film, making it impossible to manufacture printed circuit boards.

Each of the laminates thus obtained was masked except for the circuit using a screen printing machine.

The obtained laminate is 1! Plating was carried out at 72° C. with a chemical plating solution having the following composition in an aqueous solution of L.A. to obtain a copper plating film of about 30 microns on both sides of the sheet.

CuSO4/ 5H20Log EDTA” 2Na” 2H2030gHCHO(
38%) 3nlNa011
After plating 12 g, the masking was washed off, washed with water, and dried (see Table 2 for "Conductive metals").

(Write “plated” in the column.)

In addition, a laminate obtained in the same manner was coated with a 2X l
o = Platinum was deposited in a vacuum to obtain a metal film with a thickness of 1000λ ("vacuum deposition" is written in the column "Conductive metal" in Table 2).

A heat resistance test was conducted on each printed circuit board thus obtained. The results are shown in Table 2.

(Margin below) JP-A-6L-217236 (11) -'735-, 5/ The film obtained in Example 3 was evaluated for volume resistivity, dielectric constant (I MH,), dielectric loss tangent, and The withstand voltage was measured.

The volume resistivity is 1014Ω・cm and the dielectric constant is 3.5
Met. In addition, the dielectric loss tangent is 0.2, and the withstand voltage is 2.
It was 0KV/mm.

From the above results, the crosslinked product of the present invention (thin walled product obtained by heating and pressurizing the mixture) not only has good adhesion to various sintered ceramic plates, but also has excellent heat resistance and electrical resistance. It is clear that it can be used for ceramic space wiring boards because of its good insulation properties.

The printed circuit board obtained by the present invention has not only good heat resistance and heat dissipation as described above, but also has significantly improved reliability of electrical insulation, and has excellent crosslinking ability when pressurized at high temperatures. It has adhesive properties and exhibits typical effects as it was invented based on an idea completely different from that of conventional heat-resistant polymer chemistry.

(1) Since the crosslinked material layer is thermally bonded to the ceramic plate, an insulating layer with a uniform thickness and surface can be obtained. Therefore, fine-patterned circuits can be drawn using inexpensive methods such as direct plating.

(2) Excellent electrical properties (for example, insulation, withstand voltage, and dielectric loss tangent performance) and heat dissipation.

(3) The adhesive has good heat resistance and can not only be used at a temperature of 250°C or higher, but also can be used by applying pressure at a temperature of 100°C or higher. It can be bonded well to ceramic plates. For this reason, it not only takes full advantage of the heat dissipation properties of ceramics, but also makes full use of its ability to minimize dimensional changes, making it ideal for high-density packaging.

As described above, the printed circuit board of the present invention not only has good electrical properties such as insulation resistance and dielectric constant, but also has good heat dissipation, dimensional stability, heat resistance, chemical resistance, moisture resistance, etc. Not only that, but it also has features such as the ability to draw circuits on the substrate by plating or vacuum deposition.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of a portion of a typical example of a printed circuit board having a structure in which a crosslinked material is laminated on a ceramic plate. Further, FIG. 2 is an enlarged sectional view of a part of a typical example of a printed circuit board on which a circuit is drawn by vacuum deposition, plating, etc. on the substrate shown in FIG. 1, which will be described later. ■...Ceramics plate 2...Bridge 3...Conductive metal layer (circuit drawn by vacuum deposition, plating, etc.) Patent applicant: Showa Denko Co., Ltd. Person Patent Attorney Sei Kikuchi - Figure 1

Claims (1)

[Scope of Claims] (A) a ceramic layer; (B) a saponified product of (1) an ethylene-acrylic acid copolymer and/or an ethylene-methacrylic acid copolymer and (2) an ethylene-vinyl acetate copolymer; A crosslinked layer of a mixture of (C) and a conductive metal layer (C) are sequentially laminated, and the thickness of the ceramic layer is 1
00 Å to 10 mm, and the crosslinked product contains at least 80% by weight of residues having a diameter of 0.1 micron or more after extraction treatment with boiling toluene for 3 hours, and the ethylene-acrylic acid copolymer and/or ethylene in the mixture. - the mixing proportion of the methacrylic acid copolymer is from 20 to 80% by weight, the thickness of this layer is from 0.2 microns to 1000 microns, and the thickness of the conductive metal layer is from 100 Å to 200 microns, Furthermore, this layer is a printed circuit board formed by any one of a metal vapor deposition method, an electroless plating method, and a method using a combination of electroless plating and electrolytic plating.