JP2008254451A - Insulating sheet with metal foil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulation sheet with a metal foil whose cured insulation layer has high rigidity, capable of simplifying lamination work for making a multilayered board, and making the multilayered board using a metal foil without a carrier even if the thickness of the metal foil is not greater than 9 μm. <P>SOLUTION: The insulation sheet 1 with the metal foil is formed by joining integrally an insulation layer 2 with a metal foil 3 wherein the insulation layer 2 comprises a glass woven fabric 4 and a thermosetting resin 5 in a B stage state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an insulating sheet with a metal foil that is suitably used for the production of a multilayer wiring board.

  Conventionally, a multilayer wiring board has been widely produced using a prepreg 11 including a glass woven fabric and a thermosetting resin in a B-stage state. When a multilayer wiring board is manufactured using a prepreg, as shown in FIG. 5A, an inner layer material 7 having an inner layer circuit 6 provided on the surface and a metal foil 3 for forming an outer layer circuit are interposed through a prepreg 11. Generally, a multilayer board 8 shown in FIG. 5B is bonded, and a multilayer wiring board is generally manufactured by performing through-hole processing, forming an outer layer circuit, or the like on the multilayer board 8.

  In this case, in order to make the multilayer board 8, the laminating operation for superimposing the inner layer material 7, the prepreg 11, and the metal foil 3 is complicated, and thus means for further simplifying the laminating operation is required. In addition, when the inner layer material 7, the prepreg 11, and the metal foil 3 are overlapped to form the multilayer plate 8, the handleability of the metal foil 3 is reduced if the thickness of the metal foil 3 is as thin as 9 μm or less. Since it was not good, there was a problem that a metal foil with a carrier integrated with a carrier metal foil such as an aluminum foil had to be used as the metal foil 3 and the cost was increased. Therefore, even in the case of a so-called ultrathin metal foil having a thickness of 9 μm or less as a metal foil, there is a demand for a measure that can be easily laminated using a metal foil without a carrier.

  On the other hand, using the insulating sheet 1 with metal foil, a multilayer wiring board is also manufactured by a process called a build-up method. As shown in FIG. 2A, a conventional insulating sheet 1 with a metal foil is formed by integrally forming a metal foil 3 such as a copper foil and an insulating layer 2 in a B stage state (semi-cured state). The B-stage insulating layer 2 is formed by applying an epoxy resin or the like to the metal foil 3 and semi-curing it. In addition, about the insulating sheet 1 with a metal foil, it may be expressed as a metal foil with an insulating layer or a metal foil with a resin.

  When the multilayer wiring board 13 is manufactured by the build-up method using the insulating sheet 1 with metal foil, first, as shown in FIG. 2A, the inner layer material 7 provided with the inner layer circuit 6 on the surface is coated with a metal. The insulating sheet 2 with foil is laminated and laminated to form the insulating layer 2, and the insulating sheet 1 with metal foil is integrated on the surface of the inner layer material 7 as shown in FIG. Eight. In addition, although the insulating layer 2 of Fig.2 (a) is a semi-hardened state, the insulating layer 2 in FIG.2 (b)-FIG.2 (e) is the state hardened | cured by lamination molding.

  Next, the metal foil 3 at a location where electrical continuity with the inner layer circuit 6 is desired is removed by etching or the like, and then, as shown in FIG. Then, the holes 9 reaching the inner layer circuit 6 are formed in the hardened insulating layer 2. Thereafter, as shown in FIG. 2 (d), a plating layer 10 is provided on the inner surface of the hole 9 to electrically connect the inner layer circuit 6 and the metal foil 3. Next, although not shown, the circuit 12 is formed by performing etching or the like on the metal foil 3 of the multilayer plate 8. In this manner, a predetermined number of insulating sheets 1 with metal foil are sequentially laminated, and finally, a solder resist or the like is applied to the outermost laminated insulating sheet 1 with metal foil formed with a circuit 12 The multilayer wiring board 13 shown in FIG.

  As described above, when the insulating sheet 1 with a metal foil is used when the multilayer wiring board 13 is manufactured, ensuring of electrical insulation by the cured insulating layer 2 and provision of a conductor for an electric circuit by the metal foil 3 can be achieved. Can be done simultaneously. However, since the insulating layer 2 is formed only of a resin component without a base material, the rigidity of the cured insulating layer 2 is low, and warping and twisting occurs in the reflow line for mounting components on the obtained multilayer wiring board 13. It was easy to do and there was a problem that the yield fell.

  Further, since the insulating layer 2 is formed only of a resin component without a base material, if the thickness of the metal foil 3 is as thin as 9 μm or less, the handling property is not good even in the state of the insulating sheet 1 with the metal foil. As the foil 3, a so-called metal foil with a carrier integrated with a carrier metal foil such as an aluminum foil has to be used, resulting in a problem of increased costs.

In order to improve the problem that the insulating layer 2 cannot be formed thick in the conventional insulating sheet with metal foil in which the insulating layer 2 is formed only of a resin component without a base material, the inventors of the present application It is proposed to provide an organic base material formed of wholly aromatic polyamide or wholly aromatic polyester (see Patent Document 1). In the insulating sheet 1 with a metal foil provided with this organic base material, even when the thickness of the metal foil 3 is as thin as 9 μm or less, even if a metal foil without a carrier is used, the insulating sheet 1 with a metal foil has no problem with handling. However, since the rigidity of the cured insulating layer 2 is low, the problem that the warp twist easily occurs and the yield decreases in the reflow line for mounting components on the obtained multilayer wiring board 13 has not been solved.
Japanese Patent Laid-Open No. 10-235795

  The present invention has been made in view of the above circumstances. The purpose of the present invention is to simplify the laminating work for laminating work to obtain a multilayer board as compared with the case of using prepreg and copper foil individually. An insulating sheet with a metal foil, and even if the thickness of the metal foil is as thin as 9 μm or less, an insulating sheet with a metal foil that can be made into a multilayer board using a metal foil without a carrier, An insulating sheet with a metal foil having a high rigidity of a hardened insulating layer is provided so as to obtain a multilayer wiring board that does not cause a problem of warping and twisting in a reflow line for mounting components and reducing yield. There is.

  The insulating sheet with metal foil of the invention according to claim 1 is an insulating sheet with metal foil in which an insulating layer and a metal foil are integrally formed, and the insulating layer is in a glass woven fabric and a B-stage state. And a thermosetting resin.

  The insulating sheet with metal foil of the invention according to claim 2 is characterized in that, in the insulating sheet with metal foil according to claim 1, the glass woven fabric is a glass woven fabric subjected to fiber opening treatment.

The insulating sheet with metal foil of the invention according to claim 3 is the insulating sheet with metal foil according to claim 2, wherein the unit mass of the glass woven fabric is 25 to 60 g / m ² and the air permeability is 1 to 100 cc / cm ^2. / Sec.

  The insulating sheet with metal foil of the invention according to claim 4 is the insulating sheet with metal foil according to any one of claims 1 to 3, wherein the thickness of the metal foil is 9 μm or less.

  The insulating sheet with metal foil of the invention according to claim 1 is an insulating sheet with metal foil in which an insulating layer and a metal foil are integrally formed, and the insulating layer is a glass woven fabric and heat in a B-stage state. Since it is provided with a curable resin, it is an insulating sheet with a metal foil that can simplify the laminating operation as compared with the case of using the prepreg and the copper foil individually for the laminating operation to be performed as a multilayer board, and Even if the thickness of the metal foil is as thin as 9 μm or less, the metal foil is an insulating sheet with a metal foil that can be made into a multilayer board by using a metal foil without a carrier, and the cured foil has a high rigidity. It becomes an attached insulating sheet.

  The insulating sheet with metal foil of the invention according to claim 2 is the insulating sheet with metal foil of claim 1, and the glass woven fabric is a glass woven fabric that has been subjected to fiber opening treatment. In addition, there is an effect that a multilayer wiring board having high conduction reliability can be obtained.

The insulating sheet with metal foil of the invention according to claim 3 is the insulating sheet with metal foil according to claim 2, wherein the unit mass of the glass woven fabric is 25 to 60 g / m ² and the air permeability is 1 to 100 cc / cm ^2. Therefore, in addition to the effect of the invention according to claim 2, when manufacturing a multilayer wiring board by the build-up method, there is an effect that the dimensional accuracy of the hole obtained by laser processing is improved.

  The insulating sheet with metal foil of the invention according to claim 4 is the insulating sheet with metal foil according to any one of claims 1 to 3, wherein the thickness of the metal foil is 9 μm or less. In addition to the effect of the invention, there is an effect that a fine pattern can be easily formed.

  First, an embodiment according to the insulating sheet with metal foil of the present invention will be described. One embodiment according to the insulating sheet with metal foil of the present invention is shown in FIG. This insulating sheet with metal foil 1 is formed by integrally forming an insulating layer 2 and a metal foil 3, and the insulating layer 2 includes a glass woven fabric 4 and a thermosetting resin 5 in a B-stage state. . As the metal foil 3, a copper foil is preferable in terms of electrical performance and availability, and the thickness is not particularly limited, but is preferably 9 μm or less because a fine pattern can be easily formed. Examples of the thermosetting resin 5 in the B stage state include an epoxy resin, a polyimide resin, a thermosetting type polyphenylene oxide resin, and the like, but an epoxy resin is preferable in terms of adhesiveness. For the insulating layer 2, for example, a glass woven fabric is impregnated with varnish containing a thermosetting resin 5 and dried to prepare a prepreg in which the thermosetting resin 5 is in a B-stage state. It forms by heating and integrating with the foil 3.

  Since this insulating sheet 1 with a metal foil integrally forms an insulating layer 2 and a metal foil 3, when producing a multilayer board 8, for example, as shown in FIG. When the insulating sheet 1 with metal foil can be laminated to obtain the multilayer board 8 in FIG. 3B, the prepreg and the copper foil are separately used for the laminating work performed to obtain the multilayer board 8. Can be simplified and work efficiency can be improved.

  Moreover, in this insulating sheet 1 with metal foil, since the insulating layer 2 is provided with the glass woven fabric 4, the insulating sheet 1 with metal foil has stiffness even when the thickness of the metal foil 3 is as thin as 9 μm or less. Therefore, even if it does not use the metal foil with a carrier integrated with carrier metal foils, such as aluminum foil, it becomes the insulating sheet 1 with a metal foil without a problem about handling property.

  And as the glass woven fabric 4, it is preferable to use a glass woven fabric that has been subjected to fiber opening treatment because the conduction reliability in the multilayer wiring board is improved. Glass yarn, which is the raw yarn before being woven into a glass woven fabric, is generally hardened with a coupling agent or sizing agent, but water pressure is applied to the glass woven fabric or high-pressure air is blown onto it. In other words, by opening between the filaments forming the glass yarn, the glass yarn is scattered and the resin impregnation is good. It is considered that the conduction reliability in the plate is improved. Moreover, when the opening process is performed on the glass woven fabric, the opening generated at the intersection of the yarns is reduced, and the air permeability of the glass woven fabric is reduced and stabilized. Therefore, when a glass woven fabric that has been subjected to fiber opening treatment is impregnated with a resin to make a prepreg, variation due to the location of the composition ratio of the resin and glass fiber can be reduced, and as a result, variation in hole diameter during laser processing can be suppressed small. It becomes possible.

  About the process of manufacturing a multilayer wiring board by the buildup method using this insulating sheet 1 with a metal foil, it is the same as the process demonstrated by the prior art. That is, first, as shown in FIG. 2 (a), the insulating layer 1 with the metal foil is superposed on the inner layer material 7 provided with the inner layer circuit 6 on the surface, and the insulating layer 2 is cured by laminating and molding, As shown in FIG. 2 (b), the insulating sheet 1 with metal foil is integrated with the surface of the inner layer material 7 to form a multilayer board 8. Next, the metal foil 3 at a location where electrical continuity with the inner layer circuit 6 is desired is removed by etching or the like, and then, as shown in FIG. Then, the holes 9 reaching the inner layer circuit 6 are formed in the hardened insulating layer 2. Thereafter, as shown in FIG. 2 (d), a plating layer 10 is provided on the inner surface of the hole 9 to electrically connect the inner layer circuit 6 and the metal foil 3. Next, although not shown, the circuit 12 is formed by performing etching or the like on the metal foil 3 of the multilayer plate 8. In this manner, a predetermined number of insulating sheets 1 with metal foil are sequentially laminated, and finally, a solder resist or the like is applied to the outermost laminated insulating sheet 1 with metal foil formed with a circuit 12 The multilayer wiring board 13 shown in FIG.

  In this insulating sheet 1 with a metal foil, since the insulating layer 2 includes the glass woven fabric 4, compared to an insulating layer formed only of a resin component without a base material, or an insulating layer including an organic base material, The flexural modulus of the cured insulating layer 2 is high and therefore the rigidity is high. Therefore, a multilayer wiring board manufactured by the build-up method using this insulating sheet with metal foil 1 is a multilayer wiring board in which warpage and twisting hardly occur in a reflow line for mounting components.

Further, the glass woven fabric 4 is a fiber woven fabric that has been subjected to fiber opening treatment and is thin with a unit mass of 25 to 60 g / m ^2, and has an air permeability of 1 to 100 cc / cm ² / sec. Since the density unevenness of the glass fiber is further reduced and the variation in the composition ratio between the resin and the glass fiber in the laser processed portion is reduced, the holes 9 obtained by laser processing when the multilayer wiring board 13 is manufactured by the build-up method. This is more preferable because the dimensional accuracy is improved.

  Next, an embodiment according to the method for producing an insulating sheet with metal foil of the present invention will be described with reference to FIG. In this method for producing an insulating sheet with metal foil, a roll-shaped metal is used as the insulating layer, as shown in FIG. 4, using a prepreg 11 in which a glass woven fabric is impregnated with a thermosetting resin and dried. The foil 3 and the roll-shaped prepreg 11 are continuously bonded and integrated with a hot roll 14 and an unheated pressure roll 15 to obtain an insulating sheet 1 with a metal foil. Thus, since an insulating layer and metal foil are continuously bonded and integrated by the heat roll 14, the insulating sheet 1 with metal foil can be produced easily. Moreover, in this manufacturing method, since the metal foil 3 is preheated by passing through the preheating zone 16 before reaching the heat roll 14, the adhesion between the metal foil 3 and the prepreg 11 is stabilized. .

  Hereinafter, the present invention will be further described with reference to specific examples and comparative examples.

(Examples 1-8, Comparative Examples 1-4)
Varnish preparation Resin varnishes (epoxy varnish A, epoxy varnish B, PPO varnish C) in which a thermosetting resin was dissolved in a solvent were prepared at the blending ratios shown in Table 1. In addition, the thermosetting resin here represents the whole component except a solvent.

Production of Insulating Sheet with Metal Foil of Examples 1 to 8 The following three types of glass woven fabrics and the resin varnishes prepared above were combined as shown in Table 2, and the glass woven fabric was impregnated with the resin varnish, Next, heating was performed under the heating conditions shown in Table 2 to remove the solvent, and a prepreg in which a thermosetting resin was B-staged was produced.

Glass woven fabric used Glass woven fabric A: Product number WEA1078-X136 manufactured by Nitto Boseki Co., Ltd. (opening processed product, unit mass 48.1 g / m ² , air permeability 22 cc / cm ² / sec)
Glass woven fabric B: product number WEA05E-S136 (manufactured by Nitto Boseki Co., Ltd., fiber-treated product, unit mass 47.8 g / m ² , air permeability 168 cc / cm ² / sec)
Glass woven fabric C: product number WEA1035-X136 manufactured by Nitto Boseki Co., Ltd. (open fiber processed product, unit mass 27.8 g / m ² , air permeability 50 cc / cm ² / sec)
The air permeability was measured according to JIS-R-3420.

  Next, as shown in FIG. 4, the rolled metal foil (copper foil) 3 and the produced prepreg 11 are continuously bonded and integrated with a hot roll 14 and an unheated pressure roll 15. Thus, an insulating sheet 1 with metal foil was obtained. The metal foil (copper foil) 3 was preheated by passing through the preheating zone 16 at a stage before reaching the hot roll 14. The production conditions of the insulating sheet 1 with metal foil were the conditions shown in Table 2. Moreover, the following three types of copper foil were used as the copper foil. With respect to the insulating layer of the obtained insulating sheet 1 with metal foil, the resin content and the curing time were measured, and the obtained results are shown in Table 2. The curing time was determined by measuring the gelation time at 171 ° C. in accordance with IPC-TM-650-2.3.18, extruding the resin from the insulating layer.

  Handling the obtained insulating sheet 1 with a metal foil cut to 500 mm × 500 mm, investigate whether or not there is any stiffness in handling properties, and if there is stiffness and there is no problem in handling, there is no problem, there is no stiffness If there is a problem with handling, it is assumed that there is a problem and the results are shown in Table 2.

Used copper foil Copper foil a: Product number GTS-18μ (thickness 18 μm) manufactured by Furukawa Circuit Foil
Copper foil b: product number GTS-5μ (thickness 5 μm, with carrier) manufactured by Furukawa Circuit Foil
Copper foil c: Product number GTS-5μ (thickness 5 μm, no carrier) manufactured by Furukawa Circuit Foil

Preparation of Prepreg of Comparative Example 1 The glass woven fabric A and the epoxy varnish A prepared above are combined, the glass woven fabric is impregnated with a resin varnish, and then heated under the heating conditions shown in Table 3 to remove the solvent. While removing, the prepreg which made the thermosetting resin B-stage was produced. The resin content and the curing time of the obtained prepreg were measured, and the results are shown in Table 3.

Production of Insulating Sheet with Metal Foil of Comparative Examples 2 to 4 The epoxy varnish B prepared above was applied to the copper foil a or copper foil c using a roll coater, and then heated under the heating conditions shown in Table 3. Then, the solvent was removed and the thermosetting resin was changed to B stage to produce an insulating sheet with metal foil. The thickness of the insulating layer and the curing time of the obtained insulating sheet with metal foil were measured, and the results are shown in Table 3. Handle the obtained insulation sheet with metal foil cut to 500 mm x 500 mm, and check if there is a problem with handling. If there is a problem with handling, there is no problem. If there is a problem in handling, there is a problem, and the results are shown in Table 3.

Production of multilayer wiring board for evaluation Using a glass cloth base epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, FR-4 grade) with a thickness of 0.8 mm, an inner layer circuit is formed only on one side. An inner layer material was produced.

For Examples 1 to 8 and Comparative Examples 2 to 4, the insulating sheet with metal foil was disposed on the surface of the inner layer material forming the inner layer circuit, and the insulating sheet with metal foil and the inner layer material had a temperature of 170 ° C. Lamination was performed under conditions of a pressure of 2.94 MPa (30 kg / cm ² ) and a heating and pressing time of 40 minutes to obtain a multilayer board. For Comparative Example 1, one prepreg was placed on the surface of the inner layer material forming the inner layer circuit, and a copper foil was placed on the prepreg and laminated. Lamination was performed under the conditions of 94 MPa (30 kg / cm ² ) and heating and pressing time of 40 minutes to obtain a multilayer board. As the inner layer material, a material obtained by previously blackening the inner layer circuit surface of the inner layer material was used.

About each obtained multilayer board, the thickness of the hardened | cured insulating layer formed on the surface in which the inner layer circuit of the inner layer material was formed was measured for 20 points, and the average value and the variation (σ _n-1 ) were determined. The results are shown in Tables 4 and 5.

  The copper foil in the via formation position of the obtained multilayer board is removed by etching, and then the insulating layer in the portion where the copper foil is removed is removed using a laser, so that the holes reaching the inner layer circuit are formed in the insulating layer. Formed. The processing conditions were as follows: a carbon dioxide laser processing machine (Mitsubishi Electric, “ML605GTX-5100U”) was used to form a 200 μm hole under the conditions of an energy density of 30 mJ / P, a pulse width of 15 μsec, and one shot per hole. . After forming the hole, the plating layer was formed so as to cover the inner wall of the hole by electroless copper plating and electrolytic copper plating. Next, the copper foil on the surface was etched to produce a multilayer wiring board for evaluation in which 20 blocks (n = 20) of resistance value measurement patterns in which 1000 holes (vias) were connected in series were formed.

Evaluation of hardened product of insulating sheet with metal foil and prepreg Thermal expansion coefficient: After placing the copper foil a on the insulating layer side of the insulating sheet with metal foil and molding under the same conditions as in the production of the multilayer board, The copper foil removed by etching was used as a test piece, and cured using a TMA method (thermomechanical analysis) tension method at a temperature increase rate of 10 ° C./min at 50 ° C. to 150 ° C. The thermal expansion coefficient (planar direction) of the insulating layer was measured, and the obtained results are shown in Tables 4 and 5. In Comparative Example 1, the copper foil a was placed on both sides of the prepreg, molded under the same conditions, and then the copper foil on both sides was removed by etching. Direction) were measured, and the results obtained are shown in Table 5.

  Bending elastic modulus: For Examples 1 to 8, 14 prepregs prepared for producing an insulating sheet with metal foil were laminated, and for Comparative Example 1, 14 prepregs of Comparative Example 1 were stacked, and further above and below The copper foil a was placed and molded under the same conditions as in the production of the multilayer board, and then the copper foil on both sides was removed by etching was used as a test piece. For Comparative Examples 2 to 4, two insulating sheets with metal foil were stacked so that the insulating layers were in contact with each other, and after molding under the same conditions as in the production of the multilayer board, the copper foils on both sides were etched. This was removed to obtain a cured product of the insulating layer. Furthermore, the work of overlapping the insulating sheets with metal foil on the front and back of the cured product and molding under the same conditions as described above was repeated to obtain a cured product corresponding to 14 insulating layers of the insulating sheet with metal foil. did. About the obtained test piece, the bending elastic modulus was measured based on ASTM-D-790, and the obtained results are shown in Tables 4 and 5.

  Dielectric constant and dielectric loss tangent: The laminates produced for the measurement of elastic modulus were measured for dielectric constant and dielectric loss tangent according to JIS C-6481, and the obtained results are shown in Tables 4 and 5.

Pre-plating hole diameter variation: Using a laser, the minimum hole diameter of each of 100 holes at the stage where holes reaching the inner layer circuit were formed was measured using a microscope, and the hole diameter variation was obtained from the obtained measurement results. (Σ _n-1 ) was determined, and the results are shown in Tables 4 and 5.

Performance evaluation of multilayer wiring board for evaluation Conduction reliability by cooling cycle test: 1000 cycles of holding the multilayer wiring board for evaluation in two types of atmospheres of 55 ° C. and 125 ° C. for 30 minutes, The resistance value per via hole excluding the resistance value of the conductor pattern after the end of 1000 cycles and the number of disconnection occurrences in the test piece of n = 20 were obtained, and the results are shown in Tables 4 and 5.

  Conduction reliability by oil dip cycle test: A multilayer wiring board for evaluation is immersed in 260 ° C. oil for 30 seconds and then immersed in water at 25 ° C. for 15 seconds for 100 cycles, and the resistance of the conductor pattern after 100 cycles is completed. The resistance value per via excluding the value and the number of breaks in the n = 20 test piece were determined, and the results are shown in Tables 4 and 5.

  From the results of Table 2, Table 3, Table 4, and Table 5, the insulating sheets with metal foils of Examples 1 to 8 have no problem with handling properties after cutting even when the thickness of the metal foil is as thin as 9 μm or less. Moreover, in Examples 1-8, the bending elastic modulus of the hardened | cured insulating layer was higher than the insulating sheet with a metal foil of Comparative Examples 2-4 without a base material, and it was confirmed that rigidity is high. . And in Examples 1-8, a favorable result was obtained compared with Comparative Examples 2-4 without a base material in both of the conduction reliability by a thermal cycle test and the conduction reliability by an oil dip cycle test. Yes. Moreover, the thermal expansion coefficient of the hardened insulating layer in Examples 1-8 is smaller than the thermal expansion coefficient of Comparative Examples 2-4.

Furthermore, Examples 1-3 and Example 6 which are glass woven fabrics whose unit mass is 25-60 g / m < ² > and are thin, and whose air permeability is 1-100 cc / cm < ² > / second are used. It was confirmed that ˜8 had smaller pore size variations than Example 4 using a glass woven fabric having a unit mass of 47.8 g / m ² and an air permeability of 168 cc / cm ² / sec.

It is sectional drawing which shows one Embodiment which concerns on the insulating sheet with metal foil of this invention. It is sectional drawing for every process which shows the process of manufacturing a multilayer wiring board by the buildup method using the insulating sheet with metal foil. It is sectional drawing which shows the process of manufacturing a multilayer wiring board using the insulating sheet with metal foil of this invention. It is the schematic which shows one Embodiment which concerns on the manufacturing method of the insulating sheet with metal foil of this invention. It is sectional drawing which shows the process of manufacturing the multilayer wiring board in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulating sheet with metal foil 2 Insulating layer 3 Metal foil 4 Glass woven cloth 5 Thermosetting resin 6 Inner layer circuit 7 Inner layer material 8 Multilayer board 9 Hole 10 Plating layer 11 Prepreg 12 Circuit 13 Multilayer wiring board 14 Thermal roll 15 Press roll 16 Preheating zone

Claims (4)

  An insulating sheet with a metal foil in which an insulating layer and a metal foil are integrally formed, wherein the insulating layer includes a glass woven fabric and a thermosetting resin in a B-stage state. Insulating sheet with metal foil.   2. The insulating sheet with metal foil according to claim 1, wherein the glass woven fabric is a glass woven fabric subjected to fiber opening treatment. The insulating sheet with metal foil according to claim ² , wherein the unit mass of the glass woven fabric is 25 to 60 g / m ² and the air permeability is 1 to 100 cc / cm ² / sec.   The thickness of a metal foil is 9 micrometers or less, The insulating sheet with a metal foil in any one of Claim 1 thru | or 3 characterized by the above-mentioned.

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