JPH11163522A - Multilayer wiring boar and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a multilayer wiring board whose manufacture process is simple and connection reliability is high. SOLUTION: A manufacturing method is composed of a process of preparing a plurality of double-side circuit boards 1, wherein circuit 3 are provided on the both front and rear planes of an insulating layer 2 composed of polyimide resin, and the circuits 3 are electrically connected via a through hole; a process of preparing an adhesive sheet 8 which has a hole at a position corresponding to the prescribed position of the circuit 3 of the double-side board 1; a process of tentatively adhering the adhesive sheet 8 on the double-side circuit board 1; a process of filling opened part of each adhesive sheet 8 with solder paste, by printing after tentatively adhering the adhesive sheet 8, and melting the solder paste with heat to form a solder bump 9; and a process of staking each double-side circuit board 1, after forming the solder bump 9 and applying heat and pressure for entire integration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board suitable for mounting a semiconductor element or the like and a method for manufacturing the same.

[0002]

2. Description of the Related Art With the recent miniaturization and high performance of electronic devices, semiconductor devices constituting electronic devices and multilayer printed wiring boards on which the electronic devices are mounted have been reduced in size and thickness and improved in performance.
High reliability is required. In response to these demands, the mounting method has shifted from a pin insertion type package to a surface mount type package. Recently, a mounting method called bare chip mounting, in which a semiconductor element is directly mounted on a printed circuit board, has been studied. Further, with the increase in the number of pins of the semiconductor element, the necessity of increasing the number of layers of the substrate on which the semiconductor element is mounted is increasing. As a method of multi-layering, a built-up type multilayer wiring board has been proposed in which an insulating layer using a photosensitive resin and a conductor layer formed by plating or vapor deposition are alternately stacked on one or both sides of a base. However, this method has problems that the manufacturing process is complicated, the number of steps is large, the yield is low, and the delivery time is long. Alternatively, a method of forming a conductive paste on one surface (copper-coated surface) of a glass epoxy single-sided copper-clad laminate as a projection using a dispenser or the like, stacking an adhesive sheet and a copper foil, applying pressure, and repeating the process to form a multilayer structure. It has been proposed (JP-A-8-288649). However,
This method has problems in connection reliability, connection resistance, etc., and is difficult to apply to fine circuits. In addition, it is necessary to repeat pressing for the number of layers in order to increase the number of layers. There were various problems such as a long time.

On the other hand, in the bare chip mounting, the thermal expansion coefficient:
A silicon chip of 3 to 4 ppm / ° C. has a coefficient of thermal expansion of 10
Since the printed circuit board is directly bonded to the printed board at ２０20 ppm / ° C. via an adhesive, a stress is applied due to a difference in thermal expansion between the two, causing a problem that connection reliability is reduced. In addition, the above-mentioned stress also causes problems such as causing cracks in the adhesive and reducing moisture resistance. In order to alleviate such stress, a method of lowering the elastic modulus of the adhesive to achieve the effect of diffusing the stress has been carried out. However, even with these methods, sufficient connection reliability can be ensured. In order to ensure even higher connection reliability, it is essential to lower the thermal expansion coefficient of the base itself. In order to solve this problem, a Ni—Fe alloy is used as a base material, and a multilayer wiring board in which insulating layers and wiring conductors are alternately stacked thereon, or solder pads are formed on a surface layer of the multilayer wiring board by photolithography. A multilayer wiring board integrated by heating and pressurizing has been proposed (JP-A-61-212096).

[0004]

However, in this case, when copper is used as the wiring conductor, the elastic modulus of the copper is much larger than the elastic modulus of the polyimide resin forming the insulating layer. It has been difficult to reduce the coefficient of thermal expansion of the entire wiring board to as low as that of silicon constituting a semiconductor element. Moreover, since a metal thin film forming technique such as a vapor deposition method or a sputtering method is used, productivity is low and cost is high. In addition, since the formation of the solder pad is performed by a vapor deposition method or a photolithography method, a complicated process is required.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a multilayer wiring board having a simple manufacturing process and high connection reliability and a method of manufacturing the same.

[0006]

In order to achieve the above-mentioned object, the present invention provides a wiring conductor provided on both sides of an insulating layer made of an organic polymer resin, and these wiring conductors are electrically connected through through holes. A plurality of double-sided circuit boards are laminated and integrated via an adhesive layer, respectively, and a hole is formed in the adhesive layer at a predetermined position of a portion in contact with the wiring conductor of the two double-sided circuit boards sandwiching the adhesive layer. A first aspect is a multilayer wiring board in which a solder conductor is provided in the perforated portion, and the wiring conductors of the two double-sided circuit boards are electrically connected by the solder conductor. Wiring conductors are provided on both surfaces of an insulating layer made of a plurality of double-sided circuit boards in which both wiring conductors are electrically connected by through holes, and holes are formed at positions corresponding to predetermined portions of the wiring conductors of the double-sided circuit board. Adhesive sheet and A step of preparing, and a step of temporarily bonding the adhesive sheet to the double-sided circuit board in a state where the opening of the adhesive sheet is aligned with a predetermined portion of the wiring conductor provided on the double-sided circuit board, and after the temporary bonding of the adhesive sheet. Filling the solder paste into the opening of each adhesive sheet and heating and melting to form solder bumps; and, after the formation of the solder bumps, align the wiring conductors of each of the double-sided circuit boards so that predetermined electrical connections can be made. A second gist of the present invention is a method for manufacturing a multilayer wiring board including a step of stacking the above-mentioned double-sided circuit boards, and heating and pressurizing to integrate the whole.

That is, the present inventors have conducted a series of studies in order to obtain a multilayer wiring board having a simple manufacturing process and high connection reliability. As a result, according to the above manufacturing method, the multilayer wiring board can be easily manufactured. The present inventors have found that the multilayer wiring board which can be manufactured and has high connection reliability is obtained, and arrived at the present invention. That is, in the method of the present invention, the adhesive sheet is aligned and temporarily bonded to the double-sided circuit board, and after the solder bumps are formed in the openings formed in the adhesive sheet,
Since the whole double-sided circuit boards are aligned and stacked and heated and pressed to integrate the whole, a plurality of double-sided circuit boards can be integrated by a single heating and pressing. At the same time
Regardless of the number of layers of the wiring conductor, electrical connection between the wiring conductors can be performed by the single heating and pressing. Moreover, since through-holes are provided in each double-sided circuit board to electrically connect the wiring conductors on the front and back surfaces of each double-sided circuit board, the position of the through-hole and the position of the solder conductor can be set arbitrarily. The electrical connection between the wiring conductors can be made at any position. In the present invention, “preparing an adhesive sheet that is opened at a position corresponding to a predetermined portion of a wiring conductor of a double-sided circuit board” includes a case where the adhesive sheet is placed on a double-sided circuit board and then opened. It is.

In the present invention, the insulating layer may be made of Ni.
-When an Fe-based alloy foil, a titanium foil, or a ceramic material sheet is included as a core material, a Ni-Fe-based alloy foil, a titanium foil, or a ceramic material sheet is used in a ratio of one layer to two wiring conductors. Since a core material having a low coefficient of thermal expansion is included, even when copper is used as a wiring conductor, the coefficient of thermal expansion of the entire multilayer substrate can be made as close as possible to silicon. Thus, the insulating layer is made of Ni
-When an Fe-based alloy foil, a titanium foil, or a ceramic material sheet is included as a core material, the coefficient of thermal expansion can be extremely reduced, so that extremely high connection reliability can be obtained even in bare chip mounting.

Next, the present invention will be described in detail.

The method for manufacturing a multilayer wiring board of the present invention uses a double-sided circuit board comprising an insulating layer made of an organic polymer material and wiring conductors provided on both sides of the insulating layer, an adhesive sheet, and a solder paste. Can be

As the organic polymer material constituting the insulating layer, a polyimide resin is preferably used, but is not limited thereto, and may be polyetherimide, polyether sulfone, epoxy resin, phenol resin. ,
A fluorine resin or the like is used. As a metal material constituting the wiring conductor, copper is preferably used, but not limited thereto, and gold, silver, or the like is used.

Since the above-mentioned adhesive sheet becomes an insulating layer after lamination and integration, the adhesive constituting the adhesive sheet is preferably a polyimide-based adhesive or a mixed adhesive thereof in view of heat resistance, electric characteristics and the like. System, polyetherimide, phenol, etc. may be used. The thickness of the adhesive sheet is preferably set in the range of 0.01 to 1.0 mm. If it is smaller than this range, workability is poor, and irregularities and through holes between circuits cannot be filled. On the other hand, if it is larger than this range, it is difficult to fill the hole with the solder paste well, which causes a decrease in reliability. As a means for making a hole in the adhesive sheet, a conventionally known technique such as a drill or a punch can be used.

As the above-mentioned solder paste, a commercially available solder paste is used, and the particle size of the solder particles is 100 μm or less, preferably 50 μm or less, more preferably 20 μm or less.
m or less. The solder composition is not particularly limited, and may be selected according to the heat resistance required for the substrate.
The solder bumps after the lamination are brought into contact with the counter electrode to conduct, but if necessary, the substrate may be heated to a temperature higher than the melting point of the solder for metal bonding. The metal bonding may be performed simultaneously with the integration of the substrates by heating and pressing, or may be performed again by heating after the integration.

In order to reduce the thermal expansion of the substrate (to make the thermal expansion coefficient of the entire multilayer wiring substrate as close as possible to silicon), the insulating layer is made of a Ni—Fe alloy foil, a titanium foil or a ceramic material sheet as a core material. Can be arranged as Since the Ni—Fe alloy foil, titanium foil or ceramic material sheet functions to suppress the expansion of the conductor layer and the insulating layer, the thermal expansion coefficient of the foil itself must be sufficiently small.

[0015] When the core material is a Ni-Fe alloy foil, Ni-
Since the coefficient of thermal expansion changes depending on the ratio of the Fe-based alloy, Ni
The content is in the range of 31 to 50% by weight, preferably 31 to 45% by weight. If it is above or below this range, the coefficient of thermal expansion will increase, making it difficult to suppress the thermal expansion of the entire multilayer wiring board.

In the case of titanium foil, commercially available pure titanium foil and titanium alloy foil are included. As the titanium alloy, an alloy in which metals such as Al, V, Cr, Mn, Sn, and Zr are blended with Ti as a main component is used. These titanium foils have a coefficient of thermal expansion of about 8.8 to 9.0 ppm / ° C., but have a specific gravity of about 4.5 and a light weight per volume. On the other hand, examples of the ceramic material include alumina, mullite, cordierite, silicon carbide, silicon nitride, aluminum nitride, zirconia, and the like, or a mixture thereof.

The thickness of these core materials is 10 to 300 μm
It is preferred that When the thickness is less than 10 μm, it is difficult to suppress the coefficient of thermal expansion of the multilayer wiring board.
If it exceeds m, workability is reduced and reliability of through-hole plating is reduced. In addition, Ni-Fe alloy foil,
A method for electrically connecting both front and back conductor layers of a double-sided circuit board using a titanium foil or a ceramic material sheet as a core material is performed by conventional through-hole plating.

[0018]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the multilayer wiring board of the present invention. In the figure, reference numeral 1 denotes a double-sided circuit board in which a circuit (wiring conductor) 3 made of copper foil is formed on both sides of an insulating layer 2 made of a polyimide resin. In this embodiment, three double-sided circuit boards 1 are used, whereby a six-layer wiring board is manufactured as a multilayer wiring board. Reference numeral 4 denotes a through-hole plated portion formed by applying a copper plating process to a hole 1a formed in each of the double-sided circuit boards 1, and electrically connects the circuits 3 on both sides. Reference numeral 5 denotes a polyimide adhesive layer for bonding the double-sided circuit boards 1 to each other. Reference numeral 6 denotes a solder conductor for electrically connecting the circuits 3 of the two double-sided circuit boards 1 adjacent to each other.

The above multilayer wiring board can be manufactured as follows. That is, first, the conductor layers 3a made of copper foil are formed on both front and back surfaces of the insulating layer 2 made of polyimide resin.
Are prepared, and three adhesive sheets (see FIG. 4) 8 made of a polyimide-based adhesive are prepared. Holes 8a are formed in the two adhesive sheets 8 at predetermined positions (positions where the solder conductors 6 in FIG. 1 are provided). Next, as shown in FIG.
0 is drilled at a predetermined position with a drill or the like, and through-hole plating of copper is performed on the hole 1a to form a through-hole plating portion 4. The conductor layer 3a on each of the front and back surfaces of each of the base materials 10 is formed by a conventional etching method. The circuit 3 is formed by the above method, and three double-sided circuit boards 1 are manufactured. Next, as shown in FIG. 4, each of the adhesive sheets 8 is provided on the upper surface of two (three) double-sided circuit boards 1, and the opening 8 a of each adhesive sheet 8 is provided with each of the double-sided circuit boards 1. The circuit 3 is temporarily bonded at a predetermined position (position where the solder conductor 6 of FIG. 1 is provided). Next, a solder paste is put into the opening 8a of each of the adhesive sheets 8 by screen printing, and is heated and melted to form solder bumps 9 on the circuit 3 of each double-sided circuit board 1. Next, two double-sided circuit boards 1 on which the solder bumps 9 are provided and one double-sided circuit board 1 on which only the circuit 3 is formed are aligned with each other, and a plurality of the double-sided circuit boards 1 are stacked (see FIG. 6). Press and integrate. In this state, each adhesive sheet 8 becomes the adhesive layer 5, and each solder bump 9 becomes the conductor 6 made of solder. As a result, a six-layer wiring board in which three double-sided circuit boards 1 are laminated and integrated can be obtained.

As described above, in this embodiment, the three double-sided circuit boards 1 can be integrated by one heating / pressing operation, and at the same time, the electrical connection between the six-layer circuits 3 (the six-layer circuit 3). Electrical connection). Further, since solder is used, low-resistance interlayer connection can be performed. Furthermore, since the through-hole plated portions 4 are provided on each of the double-sided circuit boards 1, the positions of the through-hole plated portions 4 and the respective solder-made conductors 6 are arbitrarily set so that the electrical connection between the six layers is established. It can be performed at any position, greatly increasing the degree of freedom of design.

FIG. 7 shows another embodiment of the multilayer wiring board of the present invention. In this embodiment, a Ni—Fe alloy foil 12 is disposed as a core material on the insulating layer 2 of the double-sided circuit board 1. Other parts are the same as those of the multilayer wiring board shown in FIG. 1, and the same parts are denoted by the same reference numerals.

In this embodiment, the double-sided circuit board 1 can be manufactured as follows. That is, FIG.
As shown in the figure, a hole 12a is opened at a predetermined position (position where the through-hole plating portion 4 is provided) of the Ni-Fe-based alloy foil 12, and then a polyimide-based adhesive (base) is applied from both front and back surfaces of the Ni-Fe-based alloy foil 12. The conductive layer 3a is bonded using the insulating layer 2 of the material 10) to form a base material 10 as shown in FIG.
Is prepared. Next, as shown in FIG.
0, a hole 1a smaller than the opening 12a is formed in a portion corresponding to the opening 12a of the Ni—Fe alloy foil 12,
As shown in FIG. 11, through holes 4 formed by applying copper plating to the holes 1a electrically connect the conductor layers 3a on both the front and back surfaces. Since the coefficient of thermal expansion of the base material 10 thus obtained is governed by the Ni—Fe-based alloy as the material of the core material, the coefficient of thermal expansion can be changed by changing the ratio of Ni—Fe or the thickness of the foil. Can be adjusted. Next, the circuit 3 is formed on the conductor layers 3a on both the front and back surfaces of the base material 10 shown in FIG. 11 to produce the double-sided circuit board 1 (see FIG. 3). After that, in the same manner as in the method shown in FIGS.
A layer wiring board is manufactured.

As described above, also in this embodiment, FIG.
In the same manner as in the embodiment shown in FIG. 1, the three double-sided circuit boards 1 can be integrated by one heating and pressing, and the electrical connection between the six layers can also be performed. Moreover, 1 for the two-layer circuit 3
Since the Ni—Fe-based alloy foil 12 is disposed in the proportion of the layers, even when the circuit 3 is formed of a copper foil, the coefficient of thermal expansion of the entire six-layer wiring board can be extremely low and extremely high. Connection reliability can be obtained. In addition, since solder is used, low-resistance six-layer connection can be performed. Furthermore, since the through-hole plated portions 4 are provided on each of the double-sided circuit boards 1, each of the through-hole plated portions 4 and each of the solder conductors 6 are provided.
By setting the positions arbitrarily, the electrical connection between the six layers can be made at any positions, respectively, and the degree of freedom in design is greatly increased. In addition, in this embodiment, a multilayer wiring board having a very low coefficient of thermal expansion can be obtained.

Further, a titanium foil can be used as the core material instead of the Ni—Fe alloy foil. Titanium foil has a relatively small coefficient of thermal expansion, and can be used to manufacture a multilayer wiring board that is lightweight and has excellent corrosion resistance.

FIG. 12 shows still another embodiment of the multilayer wiring board of the present invention. In this embodiment, a sheet 13 made of a ceramic material such as alumina is provided as a core material on the insulating layer 2 of the double-sided circuit board 1. Other parts are the same as those of the multilayer wiring board shown in FIG. 1, and the same parts are denoted by the same reference numerals.

In this embodiment, the double-sided circuit board 1 can be manufactured in the same manner as the other embodiments. Since the ceramic material such as alumina is an insulating material, it is not necessary to form the holes 12a in the sheet 13 as shown in FIG. Also, in this embodiment, the same operation and effect as those of the above-described other embodiments can be obtained. In addition, in this embodiment, the process of manufacturing the double-sided circuit board 1 is simplified because it is not necessary to form the holes 12a in the sheet 13 as shown in FIG.

[0028]

EXAMPLE 1 A double-sided copper-clad polyimide substrate (manufactured by Mitsui Toatsu Co., Ltd .: NEOFLEXNEX) having a thickness of 18 μm of a copper foil layer on both sides and a thickness of 50 μm of an insulating layer 22 made of a polyimide resin.
-231R), a hole 21a is drilled at a predetermined position with a drill having a diameter of 0.2 mm, and a through-hole plating of copper having a plating thickness of 5 μm is performed (a through-hole plating portion 24 is formed). The circuit 23 was formed on the copper foil layer of FIG.
reference). Next, a polyimide-based adhesive sheet 28 (manufactured by Nippon Steel Chemical Co., Ltd.) having a hole 28a opened with a drill having a diameter of 0.2 mm:
SPB-035A) is positioned and placed on the double-sided circuit board 21, and in this state, heat and pressure is applied (30 kg / c).
m ² at 180 ° C. for 30 minutes) (see FIG. 14). Next, a solder paste (Sn8RA-3AMQ, manufactured by Nippon Superior Co., Ltd., melting point 260
C.) by screen printing, and after reflow at 290.degree. C., the flux was washed away to form solder bumps 29 (see FIG. 15). In the same manner, another double-sided circuit board 27a with solder bumps 29 and a double-sided circuit board 27b (see FIG. 16) on which the formation of the circuit 23 has been completed are manufactured. Pressure (30
Kg / cm ² at 200 ° C. for 1 hour)
A layer wiring board was produced (see FIG. 17). In FIG. 17, reference numeral 25 denotes an adhesive layer formed by an adhesive sheet 28, and reference numeral 26 denotes a solder conductor formed by solder bumps 29.

[0029]

Example 2 A polyimide precursor varnish (p-phenylenediamine, 3,3 ′,
4,4'-biphenyltetracarboxylic dianhydride is n-
A polyamic acid varnish reacted in methylpyrrolidone) is applied, dried, imidized in a nitrogen atmosphere at 400 ° C. for 1 hour, and a 20 μm-thick polyimide layer 32 a is provided to produce a copper polyimide two-layer substrate 30. (See FIG. 18). Next, a 50 μm-thick 42-alloy foil 35 (nickel 42% by weight, iron 58% by weight, thermal expansion coefficient 4.5 ppm / ° C.) having a hole 35 a drilled at a predetermined position with a drill having a diameter of 0.3 mm was formed on both the front and back surfaces. The two-layer substrate 30 is made of a polyimide-based adhesive sheet 32b (manufactured by Nippon Steel Chemical: SPB).
−035A) (see FIG. 19), and pressure and heat bonding (40 kg / cm ² , 200 ° C. for 1 hour) was performed.
A low thermal expansion double-sided substrate 36 as shown in FIG. In this low-thermal-expansion double-sided substrate 36, the insulating layer 32 is formed by the polyimide layer 32a and the polyimide-based adhesive sheet 32b. Further, a through-hole 36a was opened at the same position as the hole 35a of the 42 alloy foil 35 using a drill having a diameter of 0.2 mm, and the through-hole 36a was plated with copper in the same manner as in Example 1 (through-hole plating portion). 34), a circuit 33 was formed, and a double-sided circuit board 31 was produced. After that,
In the same manner as in Example 1, an adhesive sheet was temporarily bonded, solder bumps were formed, the whole was integrated by heating and pressing, and electrical connection between layers was performed, thereby producing a six-layer wiring board.

[0030]

EXAMPLE 3 Instead of the 42 alloy foil 35 used in Example 2, a 36 alloy foil having a thickness of 50 μm (nickel: 36% by weight, iron: 64% by weight, thermal expansion coefficient: 1.5 ppm / ° C.) was used. In the same manner as in Example 2, a six-layer wiring board was manufactured.

[0031]

Embodiment 4 A 200 μm thick aluminum nitride sheet (Al
N, thermal expansion coefficient 4.3 ppm / ° C.)
A copper-based two-layer substrate prepared by the same method as described above was used as a polyimide-based adhesive sheet (SPB-03 manufactured by Nippon Steel Chemical Co., Ltd.).
5A) using pressure and heat bonding (40 kg / cm ² , 20
0 ° C. for 60 minutes) to produce a low thermal expansion double-sided substrate.
A through-hole was formed in this low-thermal-expansion double-sided board using a drill having a diameter of 0.2 mm, and this was plated with copper through-holes in the same manner as in Example 1 to form a circuit, thereby producing a double-sided circuit board. Thereafter, the adhesive sheet was provisionally bonded in the same manner as in Example 1, solder bumps were formed, the whole was integrated by heating and pressing, and electrical connection between layers was performed, thereby producing a six-layer wiring board.

[0032]

Example 5 A six-layer wiring board was produced in the same manner as in Example 2, except that a pure titanium foil having a thickness of 50 μm (coefficient of thermal expansion: 8.8 ppm / ° C.) was used.

It was confirmed that the multilayer wiring boards of Examples 1 to 5 produced as described above consisted of six conductor layers, and that they could be connected at any position between layers. In addition, since the layers can be stacked at once instead of a method of sequentially stacking, the manufacturing process is greatly simplified. On the other hand, when the coefficient of thermal expansion of the six-layer wiring boards of Examples 1 to 5 was set in the range from room temperature (25 ° C.) to 200 ° C., the results were as follows.

[0034]

[Table 1]

As shown in Table 1, Ni-F was used as the core material.
The six-layer wiring boards of Examples 2 to 4 using an e-based alloy foil, a titanium foil, or a ceramic material sheet have extremely low coefficients of thermal expansion, and are clearly suitable for bare chip mounting.

In each of the above embodiments, the openings 8a and 28a of the adhesive sheets 8 and 28 are filled with the solder paste by screen printing. However, the present invention is not limited to this. It may be filled by a printing and transfer method.

[0037]

As described above, according to the multilayer wiring board method of the present invention, the adhesive sheet is aligned and temporarily bonded to the double-sided circuit board, and the solder bumps are formed in the openings formed in the adhesive sheet. After the formation, each double-sided circuit board is aligned, stacked, heated and pressed to integrate the whole, so that a plurality of double-sided circuit boards can be integrated by a single heating and pressing. At the same time, regardless of the number of layers of the wiring conductor, electrical connection between the wiring conductors can be performed by the single heating and pressing. Also, in the multilayer wiring board of the present invention, a plurality of double-sided circuit boards are laminated and integrated via an adhesive layer, respectively, and the adhesive layer has a portion in contact with the wiring conductors of the two double-sided circuit boards sandwiching this. A hole is drilled in the predetermined position of
Since the conductor made of solder is provided in the perforated portion, it is possible to provide a thin, high-performance, highly reliable connection substrate with low connection resistance. Moreover, since through-holes are provided in each double-sided circuit board to electrically connect the wiring conductors on the front and back surfaces of each double-sided circuit board, the position of the through-hole and the position of the solder conductor can be set arbitrarily. The electrical connection between the wiring conductors can be made at any position.

In the present invention, the insulating layer may be made of Ni.
-When an Fe-based alloy foil, a titanium foil, or a ceramic material sheet is included as a core material, a Ni-Fe-based alloy foil, a titanium foil, or a ceramic material sheet is used in a ratio of one layer to two wiring conductors. Since a core material having a low coefficient of thermal expansion is included, even when copper is used as a wiring conductor, the coefficient of thermal expansion of the entire multilayer substrate can be made as close as possible to silicon. Thus, the insulating layer is made of Ni
-When an Fe-based alloy foil, a titanium foil, or a ceramic material sheet is included as a core material, the coefficient of thermal expansion can be extremely reduced, so that extremely high connection reliability can be obtained even in bare chip mounting.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a multilayer wiring board of the present invention.

FIG. 2 is a sectional view of a substrate.

FIG. 3 is a sectional view of a double-sided circuit board.

FIG. 4 is a cross-sectional view showing a state where an adhesive sheet is temporarily bonded to a double-sided circuit board.

FIG. 5 is a cross-sectional view showing a state where solder bumps are formed on an adhesive sheet.

FIG. 6 is a cross-sectional view showing a state in which the double-sided circuit boards are stacked.

FIG. 7 is a sectional view showing another embodiment of the multilayer wiring board of the present invention.

FIG. 8 is a sectional view of a core material.

FIG. 9 is a sectional view of a base material.

FIG. 10 is a cross-sectional view showing a state in which holes are formed in a base material.

FIG. 11 is a cross-sectional view showing a state in which a base material is plated through holes.

FIG. 12 is a sectional view showing still another embodiment of the multilayer wiring board of the present invention.

FIG. 13 is a cross-sectional view of the double-sided circuit board according to the first embodiment.

FIG. 14 is a cross-sectional view showing a state where an adhesive sheet is temporarily bonded to a double-sided circuit board.

FIG. 15 is a cross-sectional view showing a state where solder bumps are formed on an adhesive sheet.

FIG. 16 is a cross-sectional view showing a state in which the double-sided circuit boards are stacked.

FIG. 17 is a cross-sectional view illustrating a six-layer wiring board according to the first embodiment.

FIG. 18 is a cross-sectional view of a two-layer base material of Example 2.

FIG. 19 is a cross-sectional view showing the procedure for producing a low expansion coefficient double-sided substrate.

FIG. 20 is a cross-sectional view of a low expansion coefficient double-sided substrate.

FIG. 21 is a cross-sectional view showing a state in which a low expansion coefficient double-sided substrate is plated with through holes.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Double-sided circuit board 2 Insulating layer 3 Circuit 4 Through-hole plating part 8 Adhesive sheet 8a Opening part 9 Solder bump

Claims (12)

[Claims] A plurality of double-sided circuit boards in which wiring conductors are provided on both surfaces of an insulating layer made of an organic polymer resin and both of these wiring conductors are electrically connected through through holes are integrally laminated via an adhesive layer. The adhesive layer is provided with a hole at a predetermined position in a portion where the adhesive layer comes into contact with the wiring conductor of the two double-sided circuit boards, a solder conductor is provided in the hole, and the solder material is provided. A multilayer wiring board, wherein the wiring conductors of the two double-sided circuit boards are electrically connected by a conductor. 2. An insulating layer made of an organic polymer resin,
2. The multilayer wiring board according to claim 1, wherein a core is made of an Fe-based alloy foil, a titanium foil or a ceramic material sheet. 3. The Ni—Fe alloy foil having a Ni content of 3
The multilayer wiring board according to claim 2, wherein the content is 1 to 50% by weight. 4. The multilayer wiring board according to claim 2, wherein the thickness of the core material is 10 to 300 μm. 5. The multilayer wiring board according to claim 1, wherein the insulating layer made of an organic polymer resin is made of a polyimide resin. 6. The multilayer wiring board according to claim 1, wherein the adhesive layer comprises a polyimide-based adhesive. 7. A plurality of double-sided circuit boards in which wiring conductors are provided on both surfaces of an insulating layer made of an organic polymer resin, and both wiring conductors are electrically connected by through holes; A step of preparing an adhesive sheet that is opened at a position corresponding to a predetermined portion; and A step of temporarily bonding the adhesive sheet, a step of filling the opening of each adhesive sheet with the solder paste after the adhesive sheet is temporarily bonded and heating and melting to form a solder bump, and a step of forming the solder bumps after the formation of the solder bump. A method of manufacturing a multilayer wiring board, comprising a step of stacking the above-mentioned double-sided circuit boards and aligning the whole by heating and pressurizing the conductors so that conductors can perform predetermined electrical connection. Law. 8. An insulating layer made of an organic polymer resin is made of Ni
8. The method for manufacturing a multilayer wiring board according to claim 7, wherein the core material comprises an Fe-based alloy foil, a titanium foil or a ceramic material sheet. 9. The Ni—Fe alloy foil having a Ni content of 3
9. The method according to claim 8, wherein the amount is 1 to 50% by weight. 10. The method according to claim 8, wherein the thickness of the core material is 10 to 300 μm. 11. The method according to claim 7, wherein the insulating layer made of an organic polymer resin is made of a polyimide resin. 12. The method according to claim 7, wherein the adhesive layer is made of a polyimide adhesive.