JP2002314222A - Printed circuit board and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed circuit board capable of obtaining high reliability when resin layers are electrically connected by using a conductor by forming the layers between glass clothes and to provide a method for manufacturing the same. SOLUTION: The method for manufacturing the printed circuit board comprises the steps of laminating the glass clothes 101 on an electric insulating base 100 before heating and pressurizing, forming the resin layers 102a and 102b on both surface of the laminated clothes between the adjacent clothes 101, and impregnating the clothes 101 with the resin of the layers 102a and 102b by heating and pressurizing. The method further comprises the steps of assuring a compression amount at the time of heating and pressurizing according to the thickness of the layer 102a between the clothes 101, densifying the conductor component of the conductor 105, assuring the adhesive properties between the conductor 105 and a wiring layer 107 by the resin layers 102b of both sides of the laminated clothes, and via hole connecting with high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to provide a resin layer between glass cloths (glass fibers) so that high reliability can be obtained when electrical connection between layers is made by a conductor such as a conductive paste. The present invention relates to a printed wiring board that can be made and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become smaller, thinner, lighter, and more sophisticated, not only are various electronic components constituting the electronic devices, but also printed wiring boards on which these electronic components are mounted. Various technological developments that enable density mounting are active. In particular, recently, with the rapid development of mounting technology, it has been strongly demanded that a multilayer wiring board capable of mounting a semiconductor chip such as an LSI at a high density and corresponding to a high-speed circuit be supplied at a low cost. . It is important for such a printed wiring board to have high electrical connection reliability and excellent high-frequency characteristics between a plurality of wiring patterns formed at a fine wiring pitch.

On the other hand, recently, there has been proposed a printed wiring board for electrically connecting between layers using a conductive paste (Japanese Patent No. 26001128). FIG. 8 shows a method for manufacturing the printed wiring board. First, FIG.
As shown in FIG. 7, a release film 6 made of polyester or the like is formed on both sides of a porous substrate 602 which is an aramid epoxy prepreg obtained by impregnating a thermosetting epoxy resin into an aramid nonwoven fabric.
01 is laminated.

[0004] Next, as shown in FIG. 8 (b), through holes 6 are formed at predetermined positions of a porous substrate 602 by a laser processing method.
03 is formed. Next, as shown in FIG. 8C, the conductive paste 604 is filled in the through holes 603. As a filling method, a porous base material 602 having a through hole 603 is placed on a table of a screen printing machine, and a conductive paste 604 is directly printed on the release film 601. At this time, the release film 601 on the printing surface plays a role of a printing mask and a role of preventing contamination of the surface of the porous substrate 602. Next, the release film 60 is applied from both sides of the porous substrate 602.
1 is peeled off.

[0005] Next, a metal foil 605 such as a copper foil is attached to both surfaces of the porous substrate 602. By heating and pressing in this state, as shown in FIG.
Is compressed and its thickness is reduced. At this time, the through hole 60
3, the binder component in the conductive paste is extruded at that time, and the bonding between the conductive components and between the conductive component and the metal foil 605 is strengthened. Densified and electrical connection between layers is obtained.

After that, the thermosetting resin and the conductive paste 604 which are the components of the porous substrate 602 are cured.
Then, as shown in FIG. 9E, the metal foil 605 is selectively etched into a predetermined pattern to complete a double-sided wiring board. Further, as shown in FIG. 9 (f), a porous substrate 606 filled with a conductive paste 608 by printing and a metal foil 607 are attached to both sides of the double-sided wiring board, and heated and pressed. As shown in FIG.
Is selectively etched into a predetermined pattern to complete a multilayer wiring board.

[0007]

However, in the case of a printed wiring board using the aramid epoxy prepreg as described above, the problem of weak adhesion between the board material and a metal foil such as a copper foil or a high water absorption rate. There was a problem.
In order to solve these problems, as an electrically insulating substrate,
It is also conceivable to use a glass epoxy prepreg in which a glass cloth is impregnated with a thermosetting epoxy resin.

However, when a glass epoxy prepreg is used, resin layers are formed on both sides of the glass cloth. When laminating copper foil on each side, if the resin layer is too thick, the resin layer is formed on the copper foil side. There is a problem that a flow occurs, and a resin flows between the conductive paste and the copper foil side, so that connection reliability cannot be obtained. In this case, if the resin layer is made thinner, on the other hand, the adhesion between the electrically insulating base material and the metal foil is deteriorated, or a sufficient compressive force is not applied to the conductor, so that connection reliability cannot be obtained. was there.

As a solution to this problem, a conductor on which a predetermined pattern is formed is laminated on one side of the electrically insulating base material, thereby compressing the conductor and obtaining the adhesion between the electrically insulating base material and the pattern. I was able to. However, this method cannot be used when manufacturing a multilayer wiring board, ie, when manufacturing a single-layer board before being laminated in multiple layers, that is, a double-sided wiring board which is a core layer.

[0010] The present invention is to solve the above-mentioned conventional problems, in which a resin layer is formed between glass cloths to perform electrical connection between layers using a conductor such as a conductive paste. It is an object of the present invention to provide a printed wiring board with high reliability and a method for manufacturing the same.

[0011]

In order to achieve the above object, a printed wiring board according to the present invention comprises: an electrically insulating substrate;
A conductor filled in a through-hole penetrating in the thickness direction of the electrically insulating substrate; and wiring layers formed on both surfaces of the electrically insulating substrate. By pressure, the wiring layer on both sides of the printed wiring board is electrically connected via the conductor, the electrical insulating substrate before the heating and pressing, at least two glass cloths Laminated, between the adjacent glass cloth, and a resin layer is formed on both sides of the laminated glass cloth, by the heating and pressing, the resin of each resin layer impregnated into the glass cloth. It is characterized by being.

According to the above printed wiring board,
The thickness of the resin layer in the middle part between the glass cloths ensures the amount of compression at the time of heating and pressurization and densifies the conductor component of the conductor. Adhesion with the wiring layer can also be ensured, and highly reliable via-hole connection can be achieved.

In the printed circuit board, the thickness of the resin layer formed between the adjacent glass cloths is
It is preferable that the thickness is larger than the thickness of the resin layers formed on both sides of the laminated glass cloth. According to the printed wiring board as described above, the compressive force applied to the conductor at the time of heating and pressing can be minimized from being dispersed in the lateral direction. Since the inflow of resin can also be suppressed, the adhesion between the conductor and the wiring layer can be further improved.

The thickness of the resin layer between the adjacent glass cloths is preferably in the range of 5 to 10 μm. According to the printed wiring board as described above, a sufficient compressive force can be applied to the conductor during heating and pressing.

Further, by laminating a plurality of the printed wiring boards and forming the wiring in multiple layers, it is possible to provide a multilayer printed wiring board which realizes highly reliable via hole connection.

Next, in the method for manufacturing a printed wiring board according to the present invention, at least two glass cloths are laminated, and a resin layer is formed between adjacent glass cloths and on both surfaces of the laminated glass cloths. Providing a through hole in the electrically insulated base material, filling the through hole with a conductor, stacking metal foil on both surfaces of the electrically insulative base material, Heating and pressurizing to reduce the thickness of the resin layer between the adjacent glass cloths and compress the conductor; and forming a wiring layer by forming the metal foil in a predetermined pattern. Features.

According to the method of manufacturing a printed wiring board as described above, the amount of compression during heating and pressing is ensured and the conductor component of the conductor is densified by the thickness of the resin layer in the intermediate portion between the glass cloths. In addition, due to the resin layers on both sides of the laminated glass cloth, adhesion between the conductor and the wiring layer can be secured, and highly reliable via hole connection can be achieved.

In the method for manufacturing a printed wiring board, the thickness of the resin layer formed between the adjacent glass cloths is larger than the thickness of the resin layers formed on both sides of the laminated glass cloth. Is preferred. According to the printed wiring board as described above, the compressive force applied to the conductor at the time of heating and pressing can be minimized from being dispersed in the lateral direction. Since the inflow of resin can also be suppressed, the adhesion between the conductor and the wiring layer can be further improved.

Further, the thickness of the electrically insulating substrate is 50
It is preferable that it is within the range of 150 μm. According to the method of manufacturing a printed wiring board as described above, a thin and shaped printed wiring board can be provided while maintaining rigidity.

The thickness of the resin layer between the adjacent glass cloths is preferably in the range of 5 to 10 μm. According to the method for manufacturing a printed wiring board as described above, according to the printed wiring board as described above, a sufficient compressive force can be applied to the conductor during heating and pressing.

Preferably, the conductor is a conductive paste. According to the method for manufacturing a printed wiring board as described above, when a compressive force is applied to the conductive paste in the through-hole, the resin component in the conductive paste is discharged from the through-hole, and the conductive component in the conductive paste is removed. Dense and highly reliable via hole connection becomes possible.

Preferably, the through holes are formed by a laser beam machine. According to the method for manufacturing a printed wiring board as described above, it is possible to easily and quickly form a through hole having a fine diameter according to the miniaturization of a wiring pattern.

Further, at least two glass cloths are laminated on both sides of the printed wiring board manufactured by using each of the above printed wiring board manufacturing methods, and between the adjacent glass cloths and the laminated glass A resin layer is formed on both sides of the cloth, and a second electric insulating base material filled with a conductor is overlapped with a through hole formed in the thickness direction, and the second electric insulating base material Bonding a metal foil to the surface to form a laminate, and heating and pressing the laminate to thin the resin layer formed between the adjacent glass cloths of the second electrically insulating substrate. And compressing the conductor of the second electrically insulating base material, and forming a wiring layer by forming the metal foil in a predetermined pattern. preferable.

According to the method of manufacturing a printed wiring board as described above, even in the second and second electrically insulating base materials, the thickness of the resin layer in the intermediate portion between the glass cloths can be reduced during heating and pressing. In addition to securing the amount of compression and densifying the conductor component of the conductor, the resin layers on both sides of the laminated glass cloth can also ensure the adhesion between the conductor and the wiring layer, and when the wiring layer is multilayered In this case, a highly reliable via hole connection can be realized.

In addition, a resin layer is formed on both sides of a glass cloth on both sides of a printed wiring board manufactured by using the above-described method for manufacturing a printed wiring board, and a conductor is formed in a through hole formed in the thickness direction. Laminating the filled second electrically insulating substrate, attaching a metal foil to the surface of the second electrically insulating substrate to form a laminate, and heating and pressing the laminate The method includes a step of compressing the conductor of the second electrically insulating base material and a step of forming the metal foil in a predetermined pattern to form a wiring layer, and it is preferable that the wiring is formed in a multilayer.

According to the method of manufacturing a printed wiring board as described above, the amount of compression during heating and pressing is ensured by the thickness of the wiring layer of the printed wiring board sandwiched between the second electrically insulating substrates. Since the adhesiveness between the conductor and the wiring layer can be ensured by the resin layer of the second electrically insulating base material, highly reliable via hole connection is possible even when the wiring layers are multilayered. Become. In this configuration, the amount of compression is smaller than the configuration in which the resin layer is formed between the glass cloths. However, since the intermediate layer is not provided, the manufacturing can be simplified and the manufacturing cost can be reduced.

A resin layer is formed on at least two sides of the glass cloth between at least two printed wiring boards formed by the above-described method of manufacturing each printed wiring board, and conductive layers are formed in through holes formed in the thickness direction. 2nd body filled
Forming a laminate by arranging an electrically insulating base material,
Heating and pressurizing the laminate to compress the conductor of the second electrically insulating base material, and it is preferable that the wiring be formed in multiple layers. According to the method for manufacturing a printed wiring board as described above, the amount of compression at the time of heating and pressing can be secured by the thickness of the wiring layer of the printed wiring board sandwiched between the printed wiring boards, and the second electric insulating property Since the adhesiveness between the conductor and the wiring layer can be ensured by the resin layer of the base material, highly reliable via hole connection is possible even when the wiring layers are multilayered. In this configuration, the amount of compression is smaller than the configuration in which the resin layer is formed between the glass cloths. However, since the intermediate layer is not provided, the manufacturing can be simplified and the manufacturing cost can be reduced.

[0028]

An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIGS. 1 and 2 are process sectional views showing a method for manufacturing a double-sided wiring board according to Embodiment 1 of the present invention. First, an electrically insulating substrate (hereinafter, referred to as “substrate”) 100 as shown in FIG. 1A was prepared. The base material 100 has two glass cloths 101 laminated thereon, and a resin layer 102a is interposed between two adjacent glass cloths 101.
A resin layer 102b is formed on each of both surfaces of the substrate.

The resin layers 102a and 102b are a thermosetting epoxy resin. The thickness of the resin layer 102a and the thickness of the resin layer 102b are different from each other.
02a has a thickness of 10 μm, and the resin layer 102b has a thickness of 5 μm.
And Further, by applying a compressive force, the base material 100
Each resin layer was in a semi-cured state so that the thickness of the resin layer could be reduced.

Next, as shown in FIG. 1B, a release film 1 made of polyester or the like is provided on the surface of each resin layer 102b.
03 was laminated. This lamination was performed at a temperature of about 120 ° C. As a result, the surface of the resin layer 102b was slightly melted, and the release film 103 could be attached. In this embodiment, the release film is 16 μm.
An m-thick polyethylene terephthalate (PET) was used.

Next, as shown in FIG. 1C, through holes 104 were formed in the substrate 101 on which the release film 103 was provided by a laser beam machine. This through hole has a hole diameter of about 1
It became 00 μm.

Next, as shown in FIG. 1D, the through-hole 104 was filled with a conductive paste 105 as a conductive material.
The filling method is as follows.
05 was directly printed on the release film 103. At this time, vacuum suction was performed from the side opposite to the printing surface via a porous sheet such as Japanese paper.

As a result, the resin component in the conductive paste 105 in the through-hole 104 could be sucked, the ratio of the conductive component in the conductive paste increased, and the conductive component could be more densely filled. The release film 10
Reference numeral 3 plays a role of a print mask and a role of preventing contamination of the surface of the resin layer 102b.

Next, as shown in FIG. 2E, the release films 103 on both sides were peeled off. In this case, the through hole 10
Since the hole diameter of No. 4 is fine, the influence of the state of adhesion between the inner peripheral portion of the through hole of the release film 103 and the outer peripheral portion of the conductive paste 105 cannot be ignored. That is, the release film 10
Due to the peeling of 3, the conductive paste 105 in the through-hole of the release film 103 may be partially or entirely peeled off from the substrate 100 together with the release film 103.

The conductive paste 105 remains on the base material 100 in various ways, but is not caught below the surface of the resin layer 102b. In the worst case, the resin layer 102b is in a worn state. The phenomenon in which the conductive paste is peeled off by the release film 103 is caused by a hole diameter of 100 μm.
It becomes remarkable when it is smaller than m. For this reason, the diameter of the through-hole is preferably 100 μm or more as in the present embodiment.

Next, as shown in FIG.
00, the metal foil 106 was placed on both sides and heated and pressed. The heating and pressurization was performed by a vacuum press. By this heating and pressing, as shown in FIG. 2 (g), the resin layer 102a,
102b flows into the glass cloth 101 and the substrate 10
0 became thinner.

Here, as described above, since the resin layer 102a in the intermediate portion of the base material 100 has a thickness of 10 μm, the amount of compression at the time of heating and pressurizing is ensured by this thickness. I have. That is, the heating and pressurization causes the through holes 10
The conductive paste 105 in FIG.
As a result, the resin component in the conductive paste 105 flows into the resin layers 102a and 102b, and the conductive component in the conductive paste 105 is densified.

The resin layers 102b on both sides of the substrate 100
As the thickness of the conductive paste 105 increases, the extent to which the compressive force is dispersed in the lateral direction (the left-right direction in the drawing) in the portion of the conductive paste 105 protruding from the base material 100 during heating and pressing increases. In the present embodiment, the resin layer 102b
Is as thin as 5 μm, the dispersion of the compressive force can be minimized, and the inflow of resin between the conductive paste 105 and the copper foil 106 can be suppressed.
Adhesion between conductive paste 105 and copper foil 106 can be ensured.

As described above, in the present embodiment, the base material 100
The thickness of the resin layer 102a in the middle portion of the substrate 100 ensures the amount of compression during heating and pressurization, densifies the conductive component of the conductive paste 105, and reduces the thickness of the resin layer 102b on both sides of the substrate 100
Is thinner than that of the resin layer 102a, the adhesion between the conductive paste 105 and the copper foil 106 is ensured, so that highly reliable via hole connection can be achieved.

After the heating and pressurizing step as described above, the substrate 1
00 and the conductive paste 105 are cured. In this case, the resin layer 102a,
Since the epoxy resin of 102b is impregnated, the substrate 10
0 is excellent in rigidity, and low water absorption and high adhesion are obtained;
It has high reliability as a printed wiring board material.

Finally, as shown in FIG. 2H, the metal foil 106 was selectively etched into a predetermined pattern to form a wiring layer 107, thereby completing a double-sided wiring board. In this case, the wiring layers 107 on the front and back of the base material 100 are made of the conductive paste 1
05 are electrically connected.

Although the thicknesses of the resin layers 102a and 102b have been described as being 10 μm and 5 μm, respectively, the thickness of the resin layer 102a is preferably in the range of 5 to 10 μm in order to secure the compression amount. The thickness of 102b is 5 to ensure the adhesion between the conductive paste 105 and the copper foil 106.
It is preferably not more than μm.

In this embodiment, the thickness of the substrate 100 is 100 μm, and the wiring layer 107 is a 12 μm-thick copper foil.

(Embodiment 2) Next, a method for manufacturing a multilayer wiring board according to Embodiment 2 of the present invention will be described with reference to FIGS. First, as shown in FIG. 3A, a substrate 200 was prepared. The base material 200 has three glass cloths 201 laminated, and a resin layer 202 is sandwiched between two adjacent glass cloths 201.
Resin layers 202 are formed on both sides of the laminated glass cloth 101, respectively. The resin layer 202 is a thermosetting epoxy resin. The thickness of each resin layer 202 was 5 μm. Therefore, the two resin layers 202 in the middle part of the base material 200 (the two resin layers 202 sandwiched between the glass cloths 201)
The total thickness of the two resin layers 202) is 10 μm. Further, each resin layer 202 was kept in a semi-cured state so that the base material 200 could be compressed and thinned.

Next, as shown in FIG.
A release film 203 made of polyester or the like was laminated on both sides of No. 00. This lamination was performed at a temperature of about 120 ° C. As a result, the surfaces of the resin layers 202 on both sides were slightly melted, and the release film 203 could be attached. In this embodiment, a 16 μm thick polyethylene terephthalate is used as the release film.

Next, as shown in FIG. 3C, through holes 204 were formed in the substrate 200 provided with the release film 203 by using a laser beam machine. This through hole has a hole diameter of about 1
It became 00 μm.

Next, as shown in FIG. 3D, the through-hole 204 was filled with a conductive paste 205 as a conductor.
The filling method is as follows.
05 was directly printed from the release film 203. At this time, vacuum suction was performed from the side opposite to the printing surface via a porous sheet such as Japanese paper.

As a result, the resin component in the conductive paste 205 in the through-hole 204 can be sucked, the ratio of the conductive component in the conductive paste 205 increases, and the conductive component can be more densely filled. . Note that the release film 203 plays a role of a print mask and a role of preventing contamination of the surface of the resin layer 202.

Next, as shown in FIG. 4E, the release films 203 on both sides were peeled off. In this case, the through hole 20
Since the hole diameter of No. 4 is fine, the influence of the state of adhesion between the inner peripheral portion of the through hole of the release film 203 and the outer peripheral portion of the conductive paste 205 cannot be ignored. That is, the release film 20
Due to the peeling of 3, the conductive paste 205 in the through hole of the release film 203 may be partially or entirely peeled off from the substrate 200 together with the release film 203.

The conductive paste 205 may remain on the substrate 200 in various ways, but is not caught below the surface of the resin layer 202 on both sides of the substrate 200. In the worst case, the resin layer 202 is in a worn state. Such a phenomenon that the conductive paste is peeled off by the release film 203 becomes remarkable when the hole diameter is smaller than 100 μm. For this reason, the diameter of the through hole is 100 μm as in the present embodiment.
It is preferable to make the above.

Next, as shown in FIG.
The metal foil 206 was overlaid on both sides of the sheet No. 00 and heated and pressed. The heating and pressurization was performed by a vacuum press. By this heating and pressing, as shown in FIG. 4 (g), the resin layer 202
It flowed into the glass cloth 201, and the thickness of the substrate 200 became thin.

Here, as described above, since the total thickness of the two resin layers 202 at the intermediate portion of the base material 200 is 10 μm, the amount of compression at the time of heating and pressing is ensured by this thickness. ing. That is, by this heating and pressurizing, the through holes 2
04, at least the base material 200
Therefore, the resin component in the conductive paste 205 flows out into the resin layer 202, and the conductive component of the conductive paste 205 is densified.

As the thickness of the resin layers 202 on both sides of the base material 200 is increased, the compressive force in the portion of the conductive paste 205 protruding from the base material 200 during heating and pressurization is increased in the horizontal direction (see FIG. To the left and right directions). In the present embodiment, since the thickness of the resin layers 202 on both sides of the base material 200 is as thin as 5 μm, the dispersion of the compressive force can be minimized, and the conductive paste 205 and the copper foil 206 The flow of resin into the space can be suppressed, and the conductive paste 205 and the copper foil 20 can be prevented from flowing.
6 can be secured.

As described above, in the present embodiment, the substrate 200
The thickness of the resin layer 202 at the intermediate portion of the substrate 200 ensures the amount of compression during heating and pressurization, densifies the conductive component of the conductive paste 205, and reduces the thickness of the resin layer 200 on both sides of the substrate 200. Since the adhesiveness between the conductive paste 205 and the copper foil 206 is ensured by making the resin layer 202 thinner than the total of the intermediate resin layer 202, highly reliable via-hole connection is possible.

After the heating and pressurizing step as described above, the substrate 2
00 and the conductive paste 205 are cured. In this case, since the epoxy resin of the resin layer 202 is impregnated in the glass cloth 201, the base material 200 has excellent rigidity, low water absorption, and high adhesion, and is high as a printed wiring board material. It will have reliability.

Finally, as shown in FIG. 4H, the metal foil 206 was selectively etched into a predetermined pattern to form a wiring layer 207, thereby completing a double-sided wiring board. In this case, the wiring layers 207 on the front and back sides of the base material 200 are made of the conductive paste 2
05 are electrically connected.

The thickness of the resin layer 202 is 5 μm each.
m, the resin layer 20 in the middle part of the substrate 200
2 is preferably in the range of 5 to 10 μm in order to secure the amount of compression, and the thickness of the resin layer 202 on both sides of the base material 200 is to ensure the adhesion between the conductive paste 205 and the copper foil 206. Therefore, it is preferable that each is 5 μm or less.

In this embodiment, the thickness of the substrate 200 is 150 μm, and the wiring layer 207 is a copper foil having a thickness of 12 μm.

(Embodiment 3) Next, Embodiment 3 of the present invention.
Will be described with reference to FIG.

First, as shown in FIG.
And two substrates 300 on both sides of the core substrate 301.
Were overlapped, and a metal foil 303 was further overlapped on both sides thereof, and heated and pressed. The heating and pressurization was performed by a vacuum press.

The base material 300 corresponds to the base material shown in FIG. 2E of the first embodiment. The base material 300 has two glass cloths 302 laminated on each other.
A resin layer 304a is sandwiched between the glass cloths 302.
Is formed, and a conductive paste 305 which is a conductor is formed in the through-hole. Also, the core substrate 301
Corresponds to the substrate shown in FIG. 2H of the first embodiment, and the conductive paste 305a and the wiring layer 306a are in close contact with each other.

As shown in FIG. 5B, the resin layers 304a and 304b flowed into the glass cloth 302 by heating and pressing, and the base material 300 was thinned. further,
The wiring layer 306a is embedded in the resin layer 304a. As in the first embodiment, also in the present embodiment, depending on the thickness of the resin layer 304a in the intermediate portion of the base material 300, the amount of compression during heating and pressing can be ensured, and the conductive component of the conductive paste 305 can be dense. it can.

The resin layers 304b on both sides of the substrate 300
Is thinner than the resin layer 304a, the adhesion between the conductive paste 305, the copper foil 303 and the wiring layer 306a can be secured.

After the heating and pressurizing step as described above, the substrate 3
00 and the conductive paste 305 are cured. In this case, the resin layers 302a, 3
02b is impregnated with the epoxy resin.
Has excellent rigidity, low water absorption and high adhesion, and has high reliability as a printed wiring board material.

Finally, as shown in FIG. 5C, the metal foil 303 was selectively etched into a predetermined pattern to form a wiring layer 306b, thereby completing a four-sided wiring board. In this case, the wiring layers 306b on the front and back of the base material 200 are electrically connected via the conductive paste 305 and the wiring layer 306a.

Although the thicknesses of the resin layers 304a and 304b have been described as being 10 μm and 5 μm, respectively, the thickness of the resin layer 304a is preferably in the range of 5 to 10 μm in order to secure the compression amount. Has a thickness of 5 μm to secure adhesion between the conductive paste 305 and the copper foil 303.
m or less.

In this embodiment, the thickness of the base material 300 is 100 μm, and the wiring layers 306 a and 306 b are copper foil having a thickness of 12 μm.

(Embodiment 4) Next, a method for manufacturing a multilayer wiring board according to Embodiment 4 of the present invention will be described with reference to FIG.

First, as shown in FIG. 6A, one core substrate 401 corresponding to the substrate shown in FIG. Two substrates 400 were prepared in which resin layers 404 were formed on both sides and conductive paste 405 as a conductor was filled in the through holes. Further, a metal foil 403 was overlapped on both sides thereof to form a laminate, which was heated and pressed. The heating and pressurization was performed by a vacuum press.

The conductive paste 405 is heated and pressed.
Is compressed, the resin component in the conductive paste 405 flows out to the resin layer 404, and the conductive component in the conductive paste 405 is densified. Further, as shown in FIG. 6B, the resin layer 404 between the wiring layer 406a and the base 400 is formed.
Flowed into the glass cloth 402, and the wiring layer 406a was embedded in the resin layer 404.

Further, in this embodiment, the wiring layer 406a
Is higher than the surface of the core substrate 401 by the thickness of the wiring layer 406a. Therefore, even after the resin layer 404 between the wiring layer 406a and the substrate 400 flows into the glass cloth 402 as described above,
The resin layer 404 on the surface of the core substrate 401 can be compressed. Therefore, in the present embodiment, a compression amount equal to or more than the thickness of the resin layer 404 can be secured.

The securing of the compression amount is described in the third embodiment.
As described above, the configuration in which the intermediate resin layer is provided between the glass cloths is excellent. However, in the present embodiment, since the intermediate resin layer is not provided, the manufacturing can be simplified and the manufacturing cost can be reduced.

Further, the thickness of the resin layer 404 is 5
Since the thickness is as thin as μm, the dispersion of the compressive force can be minimized similarly to the first embodiment, and the inflow of resin between the conductive paste 405 and the copper foil 403 can be suppressed.
Adhesion between the conductive paste 405, the copper foil 403, and the wiring layer 406a can be secured.

After the heating and pressurizing step as described above, the substrate 4
00 and the conductive paste 405 are cured. In this case, since the epoxy resin of the resin layer 404 is impregnated in the glass cloth 402, the base material 400 has excellent rigidity, low water absorption, and high adhesion as in the core substrate 401. As a result, the printed wiring board has high reliability.

Finally, as shown in FIG. 6C, the metal foil 403 was selectively etched in a predetermined pattern to form a wiring layer 406b, thereby completing a four-layer wiring board. In this case, the wiring layers 406b on the front and back of the substrate are
5 and the wiring layer 406a.

In this embodiment, the thickness of the substrate 400 is 60
μm, and 5 μm thick copper foil was used as the wiring layers 406a and 406b.

(Embodiment 5) Next, a method for manufacturing a multilayer wiring board according to Embodiment 5 of the present invention will be described with reference to FIG.

First, as shown in FIG. 7 (a), three core substrates 501 corresponding to FIG. 1 (h) manufactured in the same manner as in the first embodiment were placed on both sides of one glass cloth 502. A resin layer 504 was formed on the substrate, and two base materials 500 in which a conductive paste 505 as a conductor was filled in the through-hole were prepared. Further, the substrates 500 were sandwiched between the core substrates 501, respectively, and heated and pressed. The heating and pressurization was performed by a vacuum press.

The heating and pressurization causes the conductive paste 505
Is compressed, the resin component in the conductive paste 505 flows out to the resin layer 504, and the conductive component in the conductive paste 505 is densified. Also, as shown in FIG. 7B, the resin layer 504 between the wiring layer 506 and the base material 500 flowed into the glass cloth 502, and the wiring layer 506 was embedded in the resin layer 504.

Further, in the present embodiment, the position of the surface of the wiring layer 506 is higher than the surface of the core substrate 501 by the thickness of the wiring layer 506. Therefore, as described above, the resin layer 5 between the wiring layer 506 and the substrate 501
Even after 04 flows into the glass cloth 502, the resin layer 504 on the surface of the core substrate 501 can be compressed. For this reason, in the present embodiment, a compression amount equal to or greater than the thickness of the resin layer 504 can be secured, as in the fourth embodiment.

Further, similarly to the fourth embodiment, the base material 50
Since the intermediate layer is not provided in 0, the production can be simplified and the production cost can be reduced.

After the heating and pressurizing step as described above, the substrate 5
00 and the conductive paste 505 were cured, and electrical connection between the wiring layers 506 was obtained, thus completing a six-layer wiring board. In this case, since the glass cloth 502 is impregnated with the epoxy resin of the resin layer 504, the base material 500 is
As in the case of No. 01, excellent rigidity, low water absorption and high adhesion are obtained, and the printed wiring board has high reliability.

In this embodiment, the thickness of the substrate 500 is 60
μm, and a copper foil having a thickness of 12 μm was used as the wiring layer 500. In the third embodiment and the fifth embodiment, the thickness of the wiring layer is 12 μm, which is larger than the thickness of the resin layer. This has no special effect on the adhesion between the substrate and the substrate, since it is limited to a typical area.

In each of the above embodiments, the thickness of the substrate is not limited to the numerical value shown in each of the embodiments, but is preferably in the range of 50 to 150 μm.
Within such a range, a thin and contoured printed wiring board can be provided while maintaining rigidity.

Further, in the third to fifth embodiments, the embodiments of the multilayer wiring board have been described. However, if the number of bases and printed boards is increased, a multilayer wiring board can be obtained.

[0087]

As described above, according to the present invention, the amount of compression at the time of heating and pressurizing can be ensured and the conductor component of the conductor can be densified by the thickness of the resin layer in the intermediate portion between the glass cloths. By the resin layer on both sides of the laminated glass cloth,
Adhesion between the conductor and the wiring layer can also be ensured, and highly reliable via hole connection can be achieved.

[Brief description of the drawings]

FIG. 1 is a process cross-sectional view from preparation of a base material to filling of a conductive paste of a double-sided wiring board according to Embodiment 1 of the present invention.

FIG. 2 is a process cross-sectional view from peeling of a release film of the printed wiring board to completion of the printed wiring board according to the first embodiment of the present invention.

FIG. 3 is a process cross-sectional view from preparation of a base material of a printed wiring board to filling of a conductive paste according to the second embodiment of the present invention.

FIG. 4 is a process cross-sectional view from peeling of a release film of the printed wiring board to completion of the printed wiring board according to the second embodiment of the present invention.

FIG. 5 is a process sectional view from preparation of a base material of the multilayer wiring board to completion of the multilayer wiring board according to Embodiment 3 of the present invention.

FIG. 6 is a process cross-sectional view from preparation of a base material of the multilayer wiring board to completion of the multilayer wiring board according to Embodiment 4 of the present invention.

FIG. 7 is a process sectional view from preparation of a base material of a multilayer wiring board to completion of the multilayer wiring board according to Embodiment 5 of the present invention.

FIG. 8 is a process cross-sectional view showing an example of a conventional process from laminating a release film to a printed wiring board to compressing a base material.

FIG. 9 is a process cross-sectional view of an example from a conventional metal foil etching process for a printed wiring board to completion of the printed wiring board.

[Explanation of symbols]

100, 200, 300, 400, 500 Electrically insulating substrate 101, 201, 302, 402, 502 Glass cloth 102a, 102b, 202, 304a, 304b, 4
04 Resin layers 103, 203, release films 104, 204 Through holes 105, 205, 305, 405, 505 Conductive pastes 106, 206, 303, 403 Metal foils 107, 207, 306a, 306b, 406a, 40
6b, 506 Wiring layer 401, 501 Core substrate

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoji Ueda 1006 Kazuma Kadoma, Osaka Prefecture F-term (reference) in Matsushita Electric Industrial Co., Ltd. 5E317 AA24 BB02 BB12 CD25 CD32 GG03 GG11 5E346 CC04 CC05 CC09 CC32 CC55 DD12 EE09 FF18 GG15 HH07 HH11

Claims (13)

[Claims] An electric insulating base material, a conductor filled in a through hole penetrating in a thickness direction of the electric insulating base material, and wiring layers formed on both surfaces of the electric insulating base material. With
A printed wiring board in which the wiring layers on both surfaces are electrically connected via the conductor by heating and pressurizing the electrically insulating base material, wherein the electrically insulating base material before the heating and pressing is applied. A resin layer is formed between at least two glass cloths, between adjacent glass cloths, and on both surfaces of the laminated glass cloths, A printed wiring board, wherein a resin impregnates the glass cloth. 2. The printed wiring board according to claim 1, wherein the thickness of the resin layer formed between the adjacent glass cloths is larger than the thickness of the resin layers formed on both sides of the laminated glass cloth. . 3. The thickness of the resin layer between the adjacent glass cloths is in the range of 5 to 10 μm.
A printed wiring board according to claim 1. 4. A printed wiring board in which a plurality of printed wiring boards according to claim 1 are stacked and wiring is formed in multiple layers. 5. At least two glass cloths are laminated, and a through-hole is provided in an electrically insulating base material having a resin layer formed between adjacent glass cloths and on both surfaces of the laminated glass cloths. A step of filling the through hole with a conductor, a step of laminating a metal foil on both surfaces of the electrically insulating substrate, and heating and pressing the electrically insulating substrate to form a gap between the adjacent glass cloths. A method of forming a wiring layer by forming the metal foil into a predetermined pattern by thinning the resin layer and compressing the conductor. 6. The printed wiring board according to claim 5, wherein the thickness of the resin layer formed between the adjacent glass cloths is larger than the thickness of the resin layers formed on both sides of the laminated glass cloth. Manufacturing method. 7. The thickness of the electrically insulating substrate is 50 to 1
The method for manufacturing a printed wiring board according to claim 5, wherein the thickness is within a range of 50 μm. 8. The resin layer between the adjacent glass cloths has a thickness of 5 to 10 μm.
The method for manufacturing a printed wiring board according to any one of the above. 9. The method according to claim 5, wherein the conductor is a conductive paste. 10. The method for manufacturing a printed wiring board according to claim 5, wherein said through hole is formed by a laser beam machine. 11. A printed wiring board manufactured by using the method for manufacturing a printed wiring board according to claim 5, wherein at least two glass cloths are laminated on both sides of the printed wiring board, and the adjacent glass cloths are stacked. And a resin layer is formed on both sides of the laminated glass cloth, and a through hole formed in the thickness direction is filled with a conductor.
Forming a laminate by laminating the electrically insulative base materials and bonding a metal foil to the surface of the second electrically insulative base material; A step of thinning a resin layer formed between the adjacent glass cloths of the insulating base material to compress the conductor of the second electrically insulating base material; and forming the metal foil in a predetermined pattern. Forming a wiring layer by forming a wiring layer. 12. A resin layer is formed on both sides of a glass cloth on both sides of a printed wiring board manufactured by using the method for manufacturing a printed wiring board according to claim 5, and is formed in a thickness direction. A second electrically insulating substrate filled with a conductor is overlapped on the formed through hole, and the second
Attaching a metal foil to the surface of the electrically insulating base material to form a laminate; and heating and pressing the laminate to compress the conductor of the second electrically insulating base material, Forming a wiring pattern by forming a metal foil in a predetermined pattern to form a wiring layer. 13. A resin layer is formed on at least two sides of a glass cloth between at least two printed wiring boards formed by the method for manufacturing a printed wiring board according to claim 5, and has a thickness. Disposing a second electrically insulating base material filled with a conductor in a through hole formed in a direction to form a laminate, and heating and pressurizing the laminate to produce a second electrically insulating material. A method of manufacturing a printed wiring board in which wiring is formed in multiple layers, the method including a step of compressing a conductor of a base material.