JP2003101196A - Circuit sheet, production method therefor and production method for multilayer wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit sheet with which a circuit pattern composed of metal foil capable of thinning and miniaturizing and a ceramic green sheet are stuck by an adhesive agent or adhesive sheet, a production method for circuit sheet using a film with metal foil, and a production method for multilayer wiring board using the circuit sheet. SOLUTION: This production method uses the circuit sheet, with which the metal foil forming the circuit pattern is stuck on one side or both sides of the ceramic green sheet by the adhesive agent or adhesive sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit sheet, a method for manufacturing a circuit sheet, and a method for manufacturing a multilayer wiring board, and more particularly, a circuit for manufacturing a multilayer wiring board such as a package for accommodating semiconductor elements. The present invention relates to a sheet, a manufacturing method thereof, and a manufacturing method for manufacturing a multilayer wiring board from the circuit sheet.

[0002]

2. Description of the Related Art In recent years, electronic devices have been reduced in size, but due to the development of portable information terminals and the spread of so-called mobile computing for carrying and operating computers, the size of electronic devices has been further reduced, and they have been incorporated in these electronic devices. Further miniaturization, thinning, and high definition of a circuit are required for the multilayer wiring board to be manufactured.

Further, as represented by communication equipment, electronic equipment requiring high-speed operation has been widely used. To cope with such electronic equipment, a multilayer suitable for high-speed operation is provided. Printed wiring boards are required. The fact that high-speed operation is required includes various requirements such as accurate switching for high-frequency signals, and in order to perform high-speed operation, shorten the wiring length and It is necessary to reduce the width of the wiring and the gap between the wirings to shorten the time required for the electric signal to propagate. That is, from the viewpoint of adapting to high-speed operation, the multilayer wiring board is required to be downsized, thinned, and have high-definition circuits (high-density circuits).

Conventionally, a ceramic green sheet containing alumina or the like as a main component has been widely used as an insulating substrate in the above-mentioned multilayer wiring substrate because of its advantages such as high frequency characteristics. There is used a manufacturing method in which a conductive paste made of a refractory metal such as W or Mo is patterned by screen printing, and then the coated ceramic green sheets are laminated and fired.

However, in the method of forming a pattern of a conductor by screen printing as described above, the thickness of the conductor becomes thick, and therefore the miniaturization, thinning and high definition of a circuit required for a multilayer wiring board are required. Can no longer respond to. Therefore, Japanese Unexamined Patent Publication No. 2000-31623 discloses a metal transfer film for transferring a metal thin film to a ceramic green sheet or the like, and an electrode forming method for electronic parts.

This metal transfer film comprises a plastic film having a surface having low adhesion to a metal, a metal layer provided on the surface, and an adhesive layer provided on the surface of the metal layer, and forms an electrode. In order to transfer a metal foil of a desired shape to the ceramic green sheet using the above-mentioned metal transfer film, a method of applying a streak to the shape of an adhesive layer and transferring only that portion to the ceramic green sheet is used. Has been. However, since the adhesion between the plastic film and the metal is low, there is a problem that the metal layer peels off from the plastic film in the process until the transfer to the ceramic green sheet even after the metal layer is provided on the plastic film. was there.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to:
In order to realize the miniaturization and thinning of the multilayer wiring board using the ceramic green sheet and the high definition of the circuit, the circuit pattern made of a metal foil capable of thinning and high definition and the ceramic green sheet are adhesives. Another object of the present invention is to provide a circuit sheet adhered with an adhesive sheet, a method of manufacturing a circuit sheet using a film with a metal foil, and a method of manufacturing a multilayer wiring board using the circuit sheet.

[0008]

A circuit sheet according to claim 1 is characterized in that a metal foil having a circuit pattern is adhered to one side or both sides of a ceramic green sheet with an adhesive or an adhesive sheet. To do.

A method of manufacturing a circuit sheet according to a second aspect is
The first step of adhering a metal foil to one side of a resin film via an adhesive layer to produce a film with a metal foil, forming a circuit pattern on the metal foil of the film with a metal foil by a resist method to form a transfer sheet. Second step of producing, third step of applying an adhesive or adhering an adhesive sheet to one or both of the circuit pattern side of the transfer sheet and the ceramic green sheet, the transfer sheet and ceramic green From the fourth step of adhering the sheet with the adhesive or the adhesive sheet so that the circuit pattern side faces the ceramic green sheet, and the fifth step of peeling the adhesive-attached resin film from the transfer sheet. It is characterized by

A method for manufacturing a circuit sheet according to claim 3 is
The method of manufacturing a circuit sheet according to claim 2, wherein a via-hole conductor is formed on the ceramic green sheet before the ceramic green sheet and the transfer sheet having a circuit pattern are attached via an adhesive or the adhesive sheet. Is characterized by.

A method for manufacturing a multilayer wiring board according to claim 4 is obtained after a plurality of circuit sheets obtained by the method for manufacturing a circuit sheet according to claim 2 or 3 are laminated to form a laminate. It is characterized in that the laminate is fired.

The present invention will be described in detail below. As the circuit sheet of the present invention, a ceramic green sheet in which a metal foil having a circuit pattern formed thereon is adhered by an adhesive or an adhesive sheet is used.

As the above-mentioned ceramic green sheet,
A mixture of a ceramic powder such as alumina, a binder resin and a plasticizer is molded into a sheet with a doctor blade, a press or the like. The metal foil is not particularly limited, but a metal suitable for forming the circuit pattern of the wiring board, for example, gold, silver, copper,
A metal foil of a low resistance metal such as aluminum, or a metal foil such as an alloy containing at least one of these low resistance metals is preferably used.

The thickness of the metal foil is preferably 1 to 100 μm, more preferably 5 to 50 μm. Thickness is 1
When the thickness is less than 100 μm, the resistivity of the circuit pattern formed from the metal foil increases, which may be unsuitable for manufacturing a wiring board. When the thickness is more than 100 μm, when the metal foil is etched to form the circuit pattern, Etching becomes difficult, and it becomes difficult to obtain a highly accurate fine circuit pattern.

In addition, the surface of the metal foil may be roughened to form fine irregularities on the surface of the resin film in order to improve the adhesion with the adhesive. For example, the surface roughness Ra (JIS
Fine irregularities can be formed so that B 0601) is about 0.2 to 0.7 μm. Further, a coupling agent may be applied to the surface of the metal foil in order to enhance the adhesion between the metal foil and the adhesive.

The above-mentioned circuit sheets are the first to the first described below.
It is manufactured by the fifth step. First, in the first step, a metal foil is attached to one surface of a resin film via an adhesive layer to produce a film with a metal foil.

The resin film used for the above-mentioned metal foil-attached film is preferably one having appropriate flexibility, and examples thereof include polyesters such as polyethylene terephthalate; polyolefins such as polypropylene and polyethylene; polyvinyl chloride, polyimide, polyphenylene sulfide and the like. A film made of the above resin is used.

The thickness of the resin film is 10 to 500.
μm is preferable, and more preferably 20 to 300 μm. When the thickness is less than 10 μm, the circuit pattern is easily deformed or bent when a circuit pattern is formed from the metal foil, and the circuit pattern is easily broken, and when the thickness is more than 500 μm, the flexibility of the resin film is insufficient. Difficult to peel off.

As the above-mentioned pressure-sensitive adhesive, for example, pressure-sensitive adhesives of acrylic type, rubber type, ethylene-vinyl acetate copolymer type, silicone type and the like can be used, and of these, acrylic type pressure-sensitive adhesives are preferable. The thickness of the adhesive layer is 1 to 200 μ
m is preferable, and more preferably 1 to 100 μm.
If the thickness is less than 1 μm, sufficient adhesive strength with the metal foil cannot be obtained, causing problems such as peeling during use.
If the thickness is more than 200 μm, the adhesive may remain in the circuit pattern when the resin sheet is peeled off after the circuit sheet is attached to the ceramic green sheet as described later.

As a method for producing the above-mentioned film with a metal foil, a method of coating an adhesive on one side of a resin film, laminating a metal foil, and pressing and adhering the same with a press or the like; applying an adhesive on one side of the metal foil A conventionally known method such as a method of laminating a resin film after working and laminating it by pressing with a press or the like can be adopted.

The room-temperature adhesive force between the metal foil and the pressure-sensitive adhesive layer of the film with metal foil is preferably 0.3 to 10 N / cm, and the adhesive force at 50 ° C. is 1/2 of the room-temperature adhesive force.
The above is preferable. When the room-temperature adhesive strength is within the above range, the metal foil is retained without peeling due to etching or the like, and the adhesive-attached film can be easily peeled off by, for example, heating after attaching the ceramic green sheet. . In addition, the above-mentioned adhesive force is JIS Z
According to 0237, it is a value measured by 180 degree peel strength when peeling a resin film from a metal foil.

In the second step, a circuit pattern is formed on the metal foil of the film with metal foil by a resist method to produce a transfer sheet.

When a circuit pattern is formed on the metal foil of the above-mentioned metal foil-attached film by a resist method, a photoresist is applied to the entire surface of the metal foil, exposed through a mask having a predetermined pattern and developed, and then the photoresist is formed. The unexposed part is removed. Then, the metal foil in the non-patterned portion (the portion where the photoresist is removed) is removed by etching such as plasma etching or chemical etching. As a result, a circuit pattern is formed on the metal foil. Of course, the circuit pattern may be formed by applying a photoresist to the surface of the metal foil by screen printing or the like so as to form a predetermined pattern, and etching after exposure.

After the etching, if the photoresist remains on the circuit pattern, the remaining resist is removed by a resist removing solution and washed to obtain a transfer sheet having the circuit pattern formed on the resin film. .

A transfer sheet having a circuit pattern is prepared by using the above-mentioned film with metal foil. The metal foil is held on the resin film by an appropriate adhesive force, and the adhesive layer has a resistance to a chemical solution used for etching. Since it is provided and the chemical solution is also prevented from soaking in, inconveniences such as peeling of the metal foil at the time of forming the circuit pattern by etching are prevented. As a result, it becomes possible to form a fine and high-density circuit pattern with high accuracy.

In the third step, an adhesive is applied or an adhesive sheet is attached to one or both of the circuit pattern side and the ceramic green sheet of the transfer sheet obtained in the second step. The adhesive is not particularly limited as long as it can bond the ceramic green sheet and the metal foil, but among them, a liquid adhesive obtained by dissolving a thermoplastic resin in a liquid component is preferably used. Various additives may be added to the liquid adhesive as needed.

Examples of the thermoplastic resin include polyolefin resins such as polyethylene and polypropylene; elastomer resins such as polybutadiene, polychloroprene, polyisoprene, styrene-butadiene copolymer and acrylonitrile-butadiene copolymer; polyethylene oxide, polypropylene. Polyether resins such as oxide and polytetramethylene glycol; polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl chloride,
Ethylene-vinyl chloride copolymer, polyvinylidene chloride,
Vinyl-based resins such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, and polyvinyl ether; (meth) acrylic acid ester copolymer, styrene- (meth) acrylic acid ester copolymer, Styrene resin, polyester resin, polycarbonate resin,
Examples thereof include ketone resins, acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene copolymers, and the like. These may be used alone or in combination of two or more.

Among these thermoplastic resins, a glass transition temperature of 30 to 150 ° C. can be obtained because high adhesiveness can be exhibited.
Those having a glass transition temperature of 50 are more preferable.
Of about 150 ° C. Further, since it is easily thermally decomposed during firing, a (meth) acrylic acid ester copolymer,
Styrene- (meth) acrylic acid ester copolymer, styrene resin, polyvinyl butyral and the like are preferable.

From the viewpoint of improving adhesiveness, the liquid component preferably has a boiling point of 150 to 500 ° C. under normal pressure, and examples thereof include phthalic acid esters such as diethyl phthalate, dibutyl phthalate and di-2-ethylhexyl phthalate. -Based plasticizers; aliphatic dibasic acid ester-based plasticizers such as dibutyl adipate, di-2-ethylhexyl azelate, and di-2-ethylhexyl sebacate; phosphate-based plasticizers such as triethyl phosphate, tributyl phosphate, triphenyl phosphate Plasticizers such as agents; glycols such as ethylene glycol and diethylene glycol; glycol ethers such as diethylene glycol dimethyl ether and ethylene glycol monobutyl ether; and diethers such as 1,6-hexanediol and octanediol. Lumpur like; ketone solvents and isophorone; and ester solvents such as butyl carbitol acetate. These may be used alone,
Two or more kinds may be used in combination.

Further, in order to adjust the viscosity of the liquid adhesive and the like, the boiling point at normal pressure is 150 to 50, if necessary.
In addition to liquid components at 0 ° C, for example, toluene, xylene,
A liquid component having a boiling point of less than 150 ° C. under normal pressure such as tetrahydrofuran, ethyl acetate, methyl ethyl ketone, ethanol, methanol, water may be added.

The coating amount of the adhesive is 1-100.
g / m ² is preferable, and more preferably 1 to 50 g / m ^2.
Is. When the coating amount is less than 1 g / m ² , the adhesive force between the metal foil and the ceramic green sheet becomes insufficient, and 10
If it exceeds 0 g / m ² , the adhesive force between the metal foil after firing and the ceramic green sheet may be reduced.

As a method of applying the above-mentioned adhesive, for example,
Any method such as spraying, roll coater, flow coater, bar coater, brush and screen printing can be used.

The above-mentioned adhesive sheet is not particularly limited as long as it can bond the ceramic green sheet and the metal foil, but the above-mentioned thermoplastic resin and additives added as necessary, liquid components, etc. It is preferable to use a sheet-shaped mixture containing the above. As a method for forming into a sheet, (1) a method in which the above mixture is applied on a release film so as to have a uniform thickness, and an organic solvent or the like is volatilized by heating and drying, and (2) the above mixture is released. Examples thereof include a method of coating on the mold film so as to have a uniform thickness and cooling.

The adhesive sheet has a thickness of 1 to 100 μm.
Is preferable, and more preferably 1 to 50 μm. When the thickness is less than 1 μm, the adhesive force between the metal foil and the ceramic green sheet becomes insufficient, and when the thickness exceeds 100 μm, the adhesive force between the metal foil and the ceramic green sheet after firing may decrease.

When the metal foil and the ceramic green sheet are bonded to each other using the adhesive or the adhesive sheet, the room-temperature adhesive force is preferably 0.3 N / cm or more. If the room temperature adhesive strength is less than 0.3 N / cm, it becomes impossible to adhere the transfer sheet and the ceramic green sheet in the fourth step described later.

As the above-mentioned adhesive or adhesive sheet, it is preferable to use one that will be burned out in the firing step described later.

In the fourth step, the transfer sheet and the ceramic green sheet are attached so that the circuit pattern side faces the ceramic green sheet via the adhesive or the adhesive sheet formed in the third step. As a method for sticking, for example, an arbitrary method such as a laminator, a roller or a press can be used. Also, the attachment is 0.1
It is preferable to carry out at a normal temperature or under heating at a pressure of about N / cm ^{2 to 1} kN / cm ² .

In the fifth step, the resin film with the adhesive is peeled off from the laminate of the transfer sheet and the ceramic green sheet. If there is a method of reducing the adhesive strength of the pressure-sensitive adhesive to the metal foil by heating, UV irradiation, or the like at the time of peeling, that method may be used for peeling. In addition, it is preferable that the adhesive does not remain on the surface of the metal foil during peeling. A circuit sheet having a metal foil on the ceramic green sheet is obtained by peeling off the resin film with the adhesive.

When a multilayer wiring board is manufactured using the above-mentioned circuit sheet, via hole conductors are formed on the ceramic green sheet in order to secure conduction between the layers. This via-hole conductor is a physical method such as punching on a ceramic green sheet; carbon dioxide laser or U
It is obtained by forming a conductor in the pores by a method of opening the pores by a chemical method such as V laser and then performing electrolytic plating, electroless plating on the pores, or filling with a conductor paste. . The via-hole conductor is preferably formed prior to the step of attaching the transfer sheet and the ceramic green sheet.

By firing the circuit sheet obtained above, a single-layer wiring board can be obtained. However, manufacturing a multilayer wiring board using this circuit sheet improves the productivity of the multilayer wiring board. Is advantageous. When manufacturing a multilayer wiring board, a predetermined number of the above-mentioned circuit sheets (for example, a circuit sheet in which a via hole is formed) are arranged such that the wiring circuit layers and the ceramic green sheets are alternately located and via holes or via holes and wiring are connected. A part of the circuit is overlapped and pressure-bonded so as to form a conductive portion, and firing is performed under a condition that the ceramic green sheet can be sintered to obtain a target multilayer wiring board.

In the above firing step, not only the organic components such as the binder resin and the plasticizer in the ceramic green sheet are decomposed, but also the organic components of the adhesive and the adhesive sheet are decomposed, so that the ceramic green sheet is sintered. At the same time, the adhesion between the metal foil on which the circuit pattern is formed and the ceramic green sheet is improved. In addition, the firing needs to be performed at a temperature lower than the melting point of the metal foil used. Such a firing temperature is 300 to
1500 degreeC is preferable, More preferably, it is 400-100.
It is 0 ° C.

According to the above-described method for manufacturing a multilayer wiring board, the production of the ceramic green sheet having the via-hole conductor and the transfer sheet having the circuit sheet can be performed simultaneously in separate steps, resulting in extremely high production efficiency. Furthermore, since the circuit sheet is formed directly from the metal foil without plating on the metal foil, the circuit sheet will not be formed thicker than necessary. Deformation and strength reduction can be effectively prevented, and it is also extremely advantageous in terms of downsizing of the wiring board.

[0043]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. (Example 1) 1) Formation of via-hole conductor A via hole having a diameter of 0.1 mm was punched in a ceramic green sheet having a thickness of 150 μm with a carbon dioxide laser.
A copper paste containing copper powder plated with silver was filled in the holes to form via-hole conductors, and a ceramic green sheet for a multilayer wiring board was obtained.

2) Preparation of Film with Metal Foil An ethyl acetate solution of an acrylic adhesive having a solid content of 20% by weight was used to prepare a polyethylene terephthalate (PE) having a thickness of 25 μm.
T) After applying on one surface of the film, it was dried in an oven at 110 ° C. to volatilize ethyl acetate to obtain an adhesive film with an adhesive thickness of 20 μm. Then
Electrolytic copper foil obtained by electrolytic plating method (thickness 12μ
m) was adhered to the adhesive surface of the adhesive film with a laminator to prepare a film with metal foil.

With respect to the above film with metal foil, the adhesive strength at room temperature and 50 ° C. was measured by the following method. Room Temperature Adhesive Strength The film with metal foil prepared in 2) above is heated at 23 ° C for 30
After leaving it for a minute, the metal foil side of the film with a metal foil was fixed to a plastic plate with a double-sided adhesive tape, and the film was peeled off to perform a 180 ° peel test at a peel speed of 300 mm / min to measure the peel strength. Adhesion at room temperature is 3.5
It was N / cm. 50 ° C. Adhesive strength The metal foil side of the film with metal foil prepared in 2) above is fixed to a plastic plate with a double-sided adhesive tape and left in a constant temperature bath at 50 ° C. for 5 minutes, and then at a peeling speed of 300 mm / min.
An 80 degree peel test was performed to measure the peel strength. The adhesive strength at 50 ° C. was 0.6 N / cm.

3) Preparation of Adhesive 30 parts by weight of methacrylic acid ester copolymer having a glass transition temperature of 72 ° C. (“IBM-2” manufactured by Sekisui Plastics Co., Ltd.), di-2-ethylhexyl phthalate (manufactured by Sekisui Chemical Co., Ltd. DOP ",
After putting 30 parts by weight of a boiling point of 386 ° C.) and 40 parts by weight of butyl carbitol acetate (boiling point of 246 ° C.) in a closed container, they were dissolved in a shaker at room temperature for 24 hours to prepare an adhesive.

The adhesive strength of the above adhesive was measured at room temperature and 50 ° C. by the following method. Adhesion at room temperature The same amount of the above adhesive is applied to the same electrolytic copper foil as that used in the production of the above-mentioned film with metal foil by a bar coater.
After coating so as to be 0 g / m ² , the ceramic green sheet not having the via holes and the adhesive-coated surface of the electrolytic copper foil are superposed, and then 23 ° C., 10 N / cm
A pressure of ² was applied by a press for sticking. After leaving this adhesive for 3 hours and then at 23 ° C. for 30 minutes,
By fixing the ceramic green sheet side to a plastic plate with double-sided adhesive tape and peeling the metal foil,
A 180 degree peel test was performed at a peel rate of 300 mm / min to measure the peel strength. The room-temperature adhesive strength was 3.2 N / cm. Adhesive strength at 50 ° C After leaving an adherend similar to the adhesive strength at room temperature for 3 hours, the ceramic green sheet side is fixed to a plastic plate with double-sided adhesive tape and left in a constant temperature bath at 50 ° C for 5 minutes, then the peeling speed A 180 degree peel test was performed at 300 mm / min to measure the peel strength. The adhesive strength at 50 ° C. was 3.1 N / cm.

4) Preparation of transfer sheet A photoresist was applied to the copper foil surface of the above-mentioned metal foil-coated film, a latent image pattern was formed by exposure through a glass mask, and then the unexposed portion of the photoresist was removed. The film with foil was dipped in a ferric chloride solution and the non-patterned portion of the metal foil was removed by etching at an etching rate of 35 μm / min to form a circuit pattern. Further, using a sodium hydroxide aqueous solution, the resist remaining on the circuit pattern is removed, and PE
A transfer sheet having a circuit pattern was produced on the T film via an adhesive layer. The circuit pattern has a line width of 50.
It had a fine line portion having a line spacing of 50 μm and a line spacing of 50 μm. Further, during etching, no liquid penetration was observed between the adhesive layer and the metal foil.

5) Adhesion of Transfer Sheet and Ceramic Green Sheet On the circuit pattern side of the transfer sheet, the adhesive prepared above was applied with a bar coater to a coating amount of 20 g / m ² . Then, the circuit pattern and the via-hole conductor of the ceramic green sheet are aligned and overlapped so as to face each other, and then 23 ° C. and 100 N / cm ²
The transfer sheet was adhered to the ceramic green sheet by applying pressure with a press.

6) Peeling off the resin film with an adhesive agent The ceramic green sheet to which the above transfer sheet was adhered was left at room temperature for 3 hours and then placed on a plate heated to 50 ° C. so that the ceramic green sheet side was in contact with the plate, It was left for 1 minute. Then, the PET film with the adhesive was etched and slowly peeled by holding the end portion having no copper foil by hand to obtain a circuit sheet from which the PET film was peeled. In this circuit sheet, the circuit patterns are all transferred to the ceramic green sheet side.
No residual adhesive was found in the circuit pattern.

Example 2 Adhesive coating amount 10 g / m ²
Example 1 except that the transfer sheet and the ceramic green sheet were applied on both sides of the circuit pattern side and the ceramic green sheet side so that In the same way as
I got a circuit sheet. In the circuit sheet from which the PET film was peeled off, the circuit pattern was entirely transferred to the ceramic green sheet side, and no residual adhesive was found in the circuit pattern.

Example 3 Methacrylic acid ester copolymer having a glass transition temperature of 72 ° C. (“IBM-Made by Sekisui Plastics Co., Ltd.”
2 ”) 20 parts by weight, di-2-ethylhexyl phthalate (“ DOP ”manufactured by Sekisui Chemical Co., Ltd., boiling point 386 ° C.) 30 parts by weight, and ethyl acetate 50 parts by weight are put in a closed container, and then shaken at room temperature. And melted to prepare an adhesive.
This adhesive was applied to the release-treated surface of a PET film having a thickness of 25 μm, and ethyl acetate was volatilized in an oven at 110 ° C. to give a PET having an adhesive layer thickness of 20 μm.
An adhesive sheet with a film was obtained. A transfer sheet having a circuit pattern was produced in the same manner as in Example 1 except that the above-mentioned adhesive sheet with PET film was used instead of the adhesive. The circuit sheet with the film peeled off
The circuit pattern was completely transferred to the ceramic green sheet side, and no residual adhesive was found in the circuit pattern.

The adhesive strength of the above adhesive sheet at room temperature and 50 ° C. was measured by the following method. Room Temperature Adhesion Strength The adhesive layer side of the above-mentioned adhesive sheet with PET film was attached to a ceramic green sheet having no via hole by a laminator. Next, the PET film was peeled off, and the same electrolytic copper foil as that used in the production of the film with metal foil was attached to the adhesive layer side of the adhesive sheet with a laminator. When the room temperature adhesive strength of this adhered product was measured by the same method as in Example 1,
It was 2.6 N / cm. Adhesion at 50 ° C. Adhesion at 50 ° C. was measured by the same method as in Example 1 using the same adherent as the adhesive at room temperature, which was 2.3 N.
Was / cm.

Example 4 A circuit sheet was prepared in the same manner as in Example 3 except that the PET film-attached adhesive sheet produced in Example 3 was attached to the circuit pattern side of the transfer sheet instead of the ceramic green sheet. Got In the circuit sheet from which the film was peeled, the circuit pattern was completely transferred to the ceramic green sheet side, and no residual adhesive was found in the circuit pattern.

Each of the circuit sheets obtained in the above Examples 1 to 4
The circuit pattern and the ceramic green sheet
Stacked alternately, under nitrogen atmosphere, 1kN /
cm ²At a pressure of 900 ° C for 2 hours
This makes it possible to produce a multilayer wiring board having a six-layer structure.
It was

[0056]

The circuit sheet of the present invention has the above-mentioned constitution, and the circuit pattern made of a metal foil capable of thinning and high definition and the ceramic green sheet are adhered by an adhesive or an adhesive sheet. Therefore, a multilayer wiring board having a circuit pattern that is miniaturized and thinned and has high definition is provided. The method for producing a circuit sheet of the present invention has the above-described configuration, and since the metal foil is used as a film with a metal foil held with a relatively high adhesive force by an adhesive, when forming a circuit pattern by etching, No peeling or disconnection of the metal foil occurs, and the etching solution does not soak between the adhesive and the metal foil. Further, since the ceramic green sheet and the metal foil are adhered with a relatively high adhesive force via an adhesive or an adhesive sheet, when the circuit pattern is adhered on the ceramic green sheet and heated, it easily adheres. The resin film with agent can be peeled off to transfer the circuit pattern. Furthermore, it is extremely advantageous for manufacturing a multilayer wiring board having a small, thin, and high-density fine circuit with high accuracy, and at the same time, the via-hole conductor and the circuit pattern are formed on the ceramic green sheet in separate steps. Since it can be advanced, the production efficiency is significantly improved.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4G055 AA08 AC01 AC09 BA14 BA22                       BA83                 5E317 AA24 BB04 BB14 CC17 CD25                       CD27 CD32 GG01 GG14 GG16                 5E339 AB06 AD03 AD05 BC02 BD06                       BD07 BE11 BE13 CE01 CF15                 5E343 AA02 AA23 BB24 BB67 DD56                       DD62 GG06 GG08 GG11                 5E346 AA06 AA12 AA15 AA22 AA32                       AA43 AA51 BB16 CC16 CC32                       CC41 DD02 DD12 DD32 EE24                       EE28 FF18 GG07 GG08 GG09                       GG22 HH24 HH26 HH31

Claims (4)

[Claims] 1. A circuit sheet comprising a ceramic green sheet, and a metal foil having a circuit pattern formed thereon, which is attached to one side or both sides of the ceramic green sheet with an adhesive or an adhesive sheet. 2. A first step of producing a film with a metal foil by adhering a metal foil to one surface of a resin film via an adhesive layer, a circuit pattern is formed on the metal foil of the film with a metal foil by a resist method. The second step of producing a transfer sheet by applying the adhesive to the one or both of the circuit pattern side and the ceramic green sheet of the transfer sheet, or the third step of attaching the adhesive sheet, A fourth step of adhering the transfer sheet and the ceramic green sheet via an adhesive or an adhesive sheet so that the circuit pattern side faces the ceramic green sheet, and peeling the adhesive-attached resin film from the transfer sheet. A method of manufacturing a circuit sheet, comprising the fifth step. 3. The circuit according to claim 2, wherein a via-hole conductor is formed on the ceramic green sheet prior to the step of adhering the ceramic green sheet and the transfer sheet via an adhesive or an adhesive sheet. Sheet manufacturing method. 4. A multilayer comprising: stacking a plurality of circuit sheets obtained by the method for manufacturing a circuit sheet according to claim 2 or claim 3 to form a laminated body, and then firing the obtained laminated body. Wiring board manufacturing method.