JP5834882B2 - Multilayer circuit board and manufacturing method thereof - Google Patents

Description

  The present invention relates to a multilayer circuit board and a method for manufacturing the same.

  When a semiconductor device is mounted, a plurality of semiconductor elements and a semiconductor package substrate are electrically connected by being mounted on a multilayer circuit substrate. Here, as an example of a conventional method for manufacturing a multilayer circuit board, a batch lamination process will be described with reference to FIG. As shown in FIG. 4A, in the manufacture of the multilayer circuit board, the copper foil 101, the uncured resin layer 102, the three-layer wiring board 103, the uncured resin layer 102, and the three-layer wiring board are arranged from the bottom. 103, an uncured resin layer 102, and a copper foil 101 are laminated. The uncured resin layer 102 is a composite material including a glass cloth made of glass fiber fabric and a resin. The three-layer wiring board 103 has a pair of wiring patterns 111 on the upper side of the resin layer 110 containing glass cloth and cured. The pair of wiring patterns 111 is formed by patterning a copper foil. Furthermore, a copper foil 112 is attached to the entire bottom surface of the resin layer 110.

  In the collective lamination process, as shown in FIG. 4A, insulating layers such as resin layers 102 and 110 and conductor layers such as wiring patterns 111 and copper foils 101 and 112 are alternately arranged. After a plurality of the copper foil 101, the uncured resin layer 102, and the three-layer wiring board 103 are laminated, they are collectively molded by a heating type vacuum press. As shown in the form after vacuum pressing in FIG. 4B, the uncured resin layer 102 is cured after being thermally melted to form the resin layer 110, and the layers are integrated to form the multilayer circuit board 120. The Thereafter, a through hole (not shown) is formed at a predetermined position of the multilayer circuit board 120 as necessary. A conductive film is formed in the through hole by a plating method.

  Here, as a use application of such a multilayer circuit board 120, there is a circuit board for differential transmission, for example. In this case, the pair of wiring patterns 111 are used as signal lines for differential transmission. Further, the copper foil 112 disposed on the pair of wiring patterns 111 via the cured resin layer 110 is used as a ground layer or a power supply layer. In differential transmission, signals having opposite phases are transmitted to the two wiring patterns 111 forming a pair, so that the signal voltage can be lowered and signal transmission resistant to noise becomes possible.

  However, when the frequency of the signal for differential transmission is increased, the difference in propagation delay time between the pair of wiring patterns 111 is likely to occur due to the density of the glass fiber fabric contained in the cured resin layer 110, and the circuit is allowed. The propagation delay time may not fit.

  As a method for preventing the influence of the glass fiber fabric, for example, it is conceivable to manufacture a multilayer circuit board using a rigid flexible substrate that does not use the glass fiber fabric. Here, the rigid-flex board is formed by separately manufacturing a multilayer circuit board using a composite material and a flexible wiring board using an insulating material such as polyimide that does not contain a glass fiber fabric, and then bonding them together with an adhesive. . However, the rigid-flexible board is easily peeled off at the bonded portion due to the difference in thermal expansion coefficient and elastic modulus temperature dependency between the multilayer circuit board using the composite material and the flexible wiring board.

  Furthermore, in a multilayer circuit board manufactured without using a glass fiber fabric, the mechanical properties as an electronic component support are deteriorated. For example, in a large-sized multilayer circuit board having a side of several tens of centimeters and a stacking number exceeding 20 layers, the mechanical characteristics are significantly reduced. For this reason, the glass fiber fabric contributes to improving the dimensional stability of the circuit board, and is therefore an indispensable component in a circuit board capable of mounting fine electronic components at high density.

  Therefore, conventionally, the influence of the glass fiber fabric is reduced by weaving the glass fiber fabric in a lattice shape and forming the pair of wiring patterns 111 so as to be parallel to the glass fiber fabric. Further, by arranging the pair of wiring patterns 111 obliquely and zigzag with respect to the glass fiber fabric woven in a lattice shape, the density of the glass fiber fabric viewed from the signal line is made as uniform as possible.

US 2004181764 Specification

However, depending on the layout of the wiring pattern 111, the directions of the glass fiber fabric may happen to coincide with each other. In such a case, signal delay in that region cannot be prevented. For this reason, if the signal delay is surely prevented, the layout of the wiring pattern 111 is restricted.
Further, if a substrate is divided from a large base material in which a glass fiber fabric is woven in a lattice shape, the substrate is divided so that the glass fiber fabric is obliquely arranged, so that the unused portion increases and the manufacturing cost increases.
The present invention has been made in view of such circumstances, and an object thereof is to prevent a signal delay of differential transmission used in a multilayer circuit board.

According to one aspect of the embodiment, a pair of signal lines, a first insulating layer formed below the signal lines by using a resin material having no glass fiber fabric, of the first insulating layer A first conductive layer formed underneath and connected to a power source or a ground; a second insulating layer formed above the signal line using a resin material not having a glass fiber fabric; and the second A second conductive layer formed on the insulating layer and connected to the power source or the ground, and penetrates from the first conductive layer to the second conductive layer at a position between the pair of signal lines, and the inner wall A multilayer circuit board comprising: a plurality of through holes not having a conductive film; and a resin that covers the first conductive layer and the second conductive layer and is embedded in the through holes. Provided.

Further, according to another aspect of the embodiments, a step of forming a pair of signal lines on the first insulating layer formed of a resin having no glass fiber fabric, on the signal lines, glass fiber From the first conductive layer formed on the lower surface of the first insulating layer at a position sandwiching the pair of signal lines , the second insulating layer formed of a resin not having a fabric from the first conductive layer up to the second conductive layer formed on the upper surface of the second insulating layer through a step of forming a plurality of transmural holes having no conductive film on the inner wall, the first conductive layer and the second conductive layer And a step of embedding a resin in the through hole is provided.

  Since an insulating layer made of a resin having no glass fiber fabric is disposed between the signal line and the first and second conductive layers, the glass fiber fabric is not affected.

FIG. 1A is a cross-sectional view (part 1) illustrating an example of the manufacturing process of the multilayer circuit board according to the first embodiment of the present invention. FIG. 1B is a cross-sectional view (part 2) illustrating the example of the manufacturing process of the multilayer circuit board according to the first embodiment of the present invention. FIG. 1C is a cross-sectional view (part 3) illustrating the example of the manufacturing process of the multilayer circuit board according to the first embodiment of the present invention. FIG. 1D is a cross-sectional view (part 4) illustrating the example of the manufacturing process of the multilayer circuit board according to the first embodiment of the invention. FIG. 1E is a cross-sectional view (part 5) illustrating the example of the manufacturing process of the multilayer circuit board according to the first embodiment of the invention. FIG. 1F is a sectional view (No. 6) showing an example of the manufacturing process of the multilayer circuit board according to the first embodiment of the present invention. FIG. 1G is a sectional view (No. 7) showing an example of the manufacturing process of the multilayer circuit board according to the first embodiment of the invention. FIG. 1H is a sectional view (No. 8) showing an example of the manufacturing process of the multilayer circuit board according to the first embodiment of the invention. FIG. 11 is a sectional view (No. 9) showing an example of the manufacturing process of the multilayer circuit board according to the first embodiment of the present invention. FIG. 1J is a sectional view (No. 10) showing an example of the manufacturing process of the multilayer circuit board according to the first embodiment of the invention. FIG. 1K is a sectional view (No. 11) showing an example of the manufacturing process of the multilayer circuit board according to the first embodiment of the invention. FIG. 1L is a sectional view (No. 12) showing an example of the manufacturing process of the multilayer circuit board according to the first embodiment of the present invention. FIG. 2A is a cross-sectional view (part 1) illustrating an example of the manufacturing process of the multilayer circuit board according to the second embodiment of the present invention. FIG. 2B is a cross-sectional view (part 2) illustrating the example of the manufacturing process of the multilayer circuit board according to the second embodiment of the present invention. FIG. 2C is a cross-sectional view (part 3) illustrating the example of the manufacturing process of the multilayer circuit board according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing an example of a manufacturing process of a multilayer circuit board according to a modification of the present invention. FIG. 4 is a cross-sectional view showing an example of a manufacturing process of a conventional multilayer circuit board.

The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
The foregoing general description and the following detailed description are exemplary and explanatory only and are not intended to limit the invention.

(First embodiment)
A method for manufacturing a multilayer circuit board according to the first embodiment will be described with reference to the drawings.
First, steps required until a sectional structure shown in FIG. 1A is obtained will be described.
Copper foils 2A and 2B are attached to both surfaces of the insulating layer 1 one by one to form a double-sided copper-clad plate 3. The insulating layer 1 has flexibility and does not contain glass fiber. Further, the insulating layer 1 is made of a polyimide resin film having no glass transition temperature within the temperature range in which the multilayer circuit board is used. More preferably, the insulating layer 1 is made of a resin having the same or similar thermal expansion coefficient as the copper foils 2A and 2B. As such an insulating layer 1, for example, Upilex manufactured by Ube Industries, Ltd., which is a kind of polyimide film, can be used. The thickness of the insulating layer 1 can be arbitrarily selected, but is set to 100 μm, for example.

  The upper copper foil 2A (second conductive layer) covers the entire upper surface of the insulating layer 1, and the lower copper foil 2B (first conductive layer) covers the entire lower surface of the insulating layer 1. Subsequently, photoresist films 5A and 5B are formed on the respective surfaces of the copper foils 2A and 2B of the double-sided copper-clad plate 3 by coating. The photoresist film 5A covers the entire surface of the upper copper foil 2A, and the photoresist film 5B covers the entire surface of the lower copper foil 2B.

As shown in FIG. 1B, the upper photoresist film 5A is exposed and developed and patterned to form a resist pattern 5C. The photoresist pattern 5 </ b> C is formed by partially leaving the resist film 5 </ b> A together with the wiring pattern to be formed in a later step. On the other hand, the lower photoresist film 5B is not patterned. Here, instead of patterning the upper photoresist film 5A, the lower photoresist film 5B may be patterned.

  Thereafter, as shown in FIG. 1C, the upper copper foil 2 </ b> A is wet-etched using the resist pattern 5 </ b> C as a mask to form a pair of wiring patterns 10. The pair of wiring patterns 10 are arranged in parallel with a predetermined interval, and are used as signal lines for high-speed differential transmission, for example. On the other hand, the lower copper foil 2B is not etched because it is covered with the photoresist film 5B. The photoresist pattern 5C left on the pair of wiring patterns 10 and the photoresist film 5B protecting the lower surface copper foil 2B are removed by ashing or chemical treatment. As a result, the core material 11 in which the wiring pattern 10 is formed only on one surface of the insulating layer 1 and the lower copper foil 2B is left is obtained.

  On the other hand, as shown in FIG. 1D, another double-sided copper-clad plate 3 is formed, and a photoresist film 5A is formed by coating on the entire surface of the upper copper foil 2A. The photoresist film 5B is not applied to the lower copper foil 2B. Subsequently, the exposed lower copper foil 2B is removed by wet etching. At this time, all of the upper copper foil 2A remains because it is protected by the photoresist film 5A. Thereby, as shown to FIG. 1E, the single-sided copper clad core material 20 is obtained. As the single-sided copper-clad core material 20, a core material in which the copper foil 2 </ b> A is attached in advance only on the upper side of the insulating layer 1 may be used.

  Subsequently, as shown in FIG. 1F, a single-sided copper-clad core material 20 is laminated on the core material 11 via an adhesive layer 25. The adhesive layer 25 is disposed on the wiring pattern 10 of the core material 11, and the single-sided copper-clad core material 20 brings the resin layer 1 into close contact with the adhesive layer 25. For the adhesive layer 25, for example, TFA-860FB manufactured by Kyocera Chemical is used, and the thickness thereof is 25 μm.

  Thereafter, the core material 11 and the single-sided copper-clad core material 20 are integrated by a vacuum press capable of heating. As a result, as shown in FIG. 1G, a three-layer plate 31 is formed. The three-layer board 31 has a pair of wiring patterns 10 sandwiched between the upper and lower insulating layers 1, the copper foil 2 </ b> B disposed via the lower insulating layer 1 (first insulating layer), and the upper insulating film 1 (first 2A), the copper foil 2A is disposed via the insulating layer 2). The widths of the copper foils 2A and 2B are sufficiently larger than the width of each wiring pattern 10. Such a structure is a stripline structure in which the wiring pattern 10 is a signal line and the upper and lower copper foils 2A and 2B are power supply layers or ground layers.

Next, steps required until a sectional structure shown in FIG.
A photoresist film 32A is formed by coating on the surface of the upper copper foil 2A. Similarly, a photoresist film 32B is formed by coating on the surface of the lower copper foil 2B. Further, each of the photoresist films 32A and 32B is exposed and developed to be patterned. The resist patterns 33A and 33B formed at this time are formed by leaving the photoresist films 32A and 32B together with the wiring pattern to be formed in a later step.

  Subsequently, the copper foils 2A and 2B are wet-etched using the resist patterns 33A and 33B as a mask. The copper foil 2A exposed from the resist pattern 33A and the copper foil 2B exposed from the resist pattern 33B are removed. Thereby, the three-layer wiring board 41 having the surface wiring pattern 35 on each of the upper surface and the lower surface is formed.

The surface wiring pattern 35 includes ground layers 36 and 37 disposed above and below the pair of wiring patterns 10 and wiring patterns 38 and 39 formed in regions where the pair of wiring patterns 10 do not exist. One of the ground layers 36 and 37 may be used as a power supply layer, or both may be used as a power supply layer. The wiring patterns 38 and 39 are electrically connected to a circuit (not shown) or other components. Thus, the three-layer wiring board 41 is a multilayer circuit board in which the strip line structure having the pair of wiring patterns 10 and the wiring patterns 38 and 39 are integrally formed. Since the wiring patterns 38 and 39 are not formed above and below the pair of wiring patterns 10 used as signal lines for differential transmission, no crosstalk occurs between the wiring pattern 10 and the wiring patterns 38 and 39.

Next, steps required until a sectional structure shown in FIG.
The resist patterns 33A and 33B left on the surface wiring pattern 35 are removed by ashing or chemical treatment. Subsequently, a plurality of through holes 42 are formed at predetermined positions of the three-layer wiring board 41 using a mechanical drill (not shown). The through holes 42 penetrate from the upper surface wiring pattern 35 (copper foil 2 </ b> A) to the lower surface wiring pattern 35 (copper foil 2 </ b> B), and are formed one by one at positions sandwiching at least the wiring pattern 10. Although not shown, the through hole 42 may be formed elongated along the wiring pattern 10.

  Thereafter, a large number of substrate materials including the three-layer wiring board 41 are laminated. In this embodiment, as shown in FIG. 1J, from the bottom, the copper foil 44, the uncured resin layer 43, the three-layer wiring board 41, the uncured resin layer 43, the three-layer wiring board 41, and the uncured resin Layer 43 and copper foil 44 are laminated. The uncured resin layer 43 has a configuration in which a glass fiber fabric 43B is contained in a thermosetting resin 43A such as an epoxy resin, and the glass fiber fabric is, for example, a glass cloth laminated so as to intersect in two directions. It has become. The number of stacked layers and the types of components that are arranged and displayed in FIG. 1I are not limited thereto. For example, the copper foil 44, the uncured resin layer 43, the three-layer wiring board 41, the uncured resin layer 43, and the copper foil 44 may be laminated.

  As shown in FIG. 1K, in a state where the three-layer wiring board 41 and the like are laminated, an uncured resin layer 43 (second interlayer insulating layer) is formed on the ground layer 36 and the wiring pattern 38 on the upper side of the three-layer wiring board 41. ) Are closely arranged. For this reason, the wiring groove 35A between the ground layer 36 and the wiring pattern 38 is hollow. Similarly, an uncured resin layer 43 (first interlayer insulating layer) is disposed in close contact with the ground layer 37 below the three-layer wiring board 41 and the wiring pattern 39. For this reason, the wiring groove 35 </ b> A between the ground layer 37 and the wiring pattern 39 is hollow. Furthermore, the through hole 42 remains hollow.

Next, steps required until a sectional structure shown in FIG.
After the uncured resin layer 43 and the copper foil 44 are stacked on the upper and lower sides of the three-layer wiring board 41, they are laminated together by a vacuum press. The resin 43A is filled in the grooves 35A such as the wiring patterns 38 and 39 in the process in which the resin 43A of the resin layer 43 is melted and cured by heating during vacuum pressing. Similarly, the melted resin 43 </ b> A is embedded in the through hole 42 of the three-layer wiring board 41. When the resin is cured in this state, the through hole 42 is filled with the resin 43A. Further, each of the three-layer wiring boards 41 is sandwiched between a pair of upper and lower cured resin layers 45 to form an integrated multilayer circuit board 51.

Here, the resin 43A is filled in the through-holes 42 at the time of batch molding, so that the pair of resin layers 43 sandwiching the three-layer wiring board 41 up and down are integrally cured. The resin 43 </ b> A that is integrated vertically through the through-hole 42 functions as an eyelet for each three-layer wiring board 41. That is, since the three-layer wiring board 41 is firmly pressed from above and below by the resin layer 45, it cannot swell. For example, when heat is applied from the outside, gas is generated in the adhesive layer 25, and when the gas is collected, the three-layer wiring board 41 is expanded by a force for expanding the gas. Thus, the resin layer 1 and the wiring pattern 10 may be easily peeled off. However, in this multilayer circuit board 51, the resin 43A connected up and down through the through hole 42 presses down the three-layer wiring board 41 from above and below, thereby preventing the three-layer wiring board 41 from bulging and the insulating layer 1 And delamination of the adhesive layer 25 and the wiring pattern 10 are prevented.

As described above, according to this embodiment, since a resin material such as a polyimide film having no glass fiber fabric is used for the insulating layer 1 of the three-layer wiring board 41 having the wiring pattern 10 incorporated therein, the glass fiber fabric is used. Can eliminate the influence of density. When the pair of wiring patterns 10 are used for differential transmission, signal delay can be reduced and a highly reliable multilayer circuit board can be obtained.
The three-layer wiring board 41 is easy to handle because the stripline structure is integrally formed. For example, the multilayer circuit board 51 is thinner than the conventional multilayer circuit board 120 shown in FIG.

  Since the through-hole 42 is formed in the three-layer wiring board 41 and the resin 43A is embedded in the through-hole 42 at the time of batch lamination, the pair of resin layers 45 and the through-hole 42 sandwiching the three-layer wiring board 41 are provided. The delamination of the three-layer wiring board 41 can be prevented by the resin 43A. As a result, the multilayer circuit board 51 can achieve high dimensional accuracy, high reliability, and thermal stability. Since the through hole 42 is formed at a position between which the pair of wiring patterns 10 are sandwiched, delamination of the region where the pair of wiring patterns 10 is formed can be prevented more reliably. The resin 43A is preferably filled in the through-hole 42 without any gap, but may have a gap in part as long as it has a strength capable of preventing delamination.

  Furthermore, since the insulating layer 1 is manufactured using a material that does not undergo a glass transition within the operating temperature range of the multilayer circuit board 51, warping and peeling are unlikely to occur between the insulating layer 1 and the surface wiring pattern 35 using the copper foil 2. . For this reason, the three-layer wiring board 41 can be handled as a unit, and the reliability within the operating temperature range can be improved.

(Second Embodiment)
A second embodiment will be described with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals. Moreover, the description which overlaps with 1st Embodiment is abbreviate | omitted.
First, as shown in FIGS. 1A to 1I, a three-layer wiring board 41 is formed, and a through hole 42 is formed so as to sandwich a pair of wiring patterns 10. Subsequently, as shown in FIG. 2A, a conductive film 62 such as copper is grown on the inner wall of the through hole 42. The conductive film 62 is formed to a predetermined thickness by an electrolytic plating method or an electroless plating method. The upper and lower ground layers 36 and 37 of the pair of wiring patterns 10 are electrically connected by the conductive film 62 in the through hole 42. The ground layers 36 and 37 can also be used as a power supply pattern.

  2B, the copper foil 44, the uncured resin layer 43, the three-layer wiring board 61 in which the conductive film 62 is formed in the through hole 42, the uncured resin layer 43, and the three-layer wiring are formed from below. A plate 61, an uncured resin layer 43, and a copper foil 44 are laminated. At this stage, the wiring groove 35A between the ground layer 37 and the wiring pattern 39 is hollow. Furthermore, the through hole 42 remains hollow.

  Subsequently, as shown in FIG. 2C, a multilayer circuit board 65 is formed by batch lamination by vacuum pressing. The resin 43A is filled in the grooves 35A such as the wiring patterns 37 and 39 in the process in which the resin 43A of the resin layer 43 is melted and cured by heating during vacuum pressing. Similarly, the molten resin 43 </ b> A is filled in the through hole 42 of the three-layer wiring board 61. When the resin is cured in this state, the through hole 42 is filled with the resin 43A. Further, a multilayer circuit board 65 is formed by integrating each three-layer wiring board 61 between a pair of upper and lower cured resin layers 45.

  Here, the resin 43 </ b> A filled in the through hole 42 becomes an eyelet, and the resin layers 43 arranged above and below the three-layer wiring board 41 prevent the adhesive layer 23 from bulging. Further, the conductive film 62 formed on the inner wall of the through hole 42 also functions as an eyelet to prevent the adhesive layer 23 from bulging.

  As described above, according to this embodiment, since the conductive film 62 is formed in the through hole 42 of the three-layer wiring board 61, the pair of resin layers 45 sandwiching the three-layer wiring board 41 and the inside of the through hole 42 are provided. The delamination of the three-layer wiring board 41 can be further prevented by the resin 43A. Other operations and effects are the same as those in the first embodiment.

Here, a modification of the embodiment will be described.
As shown in FIG. 3, the pair of ground layers 36 and 37 sandwiching the pair of wiring patterns 10 may be partitioned by notches 68. Although not shown, a notch 68 may be formed in the three-layer wiring board 41 shown in FIG. 1I.

  All examples and conditional expressions given here are intended to help the reader understand the inventions and concepts that have contributed to the promotion of technology, and such examples and It is to be construed without being limited to the conditions, and the organization of such examples in the specification is not related to showing the superiority or inferiority of the present invention. While embodiments of the present invention have been described in detail, various changes, substitutions and variations can be made thereto without departing from the spirit and scope of the present invention.

The features of the above embodiment will be added below.
(Supplementary Note 1) A pair of signal lines, a first insulating layer formed of resin, formed below the signal lines, and formed below the first insulating layer, and connected to a power source or a ground. A first conductive layer; a second insulating layer formed above the signal line and made of resin; and a second insulating layer formed on the second insulating layer and connected to a power source or a ground. A multilayer circuit board comprising a conductive layer.
(Supplementary Note 2) A through-hole penetrating from the first conductive layer to the second conductive layer, a resin that covers the first conductive layer and the second conductive layer, and is embedded in the through-hole The multilayer circuit board according to appendix 1, characterized by comprising:
(Additional remark 3) It has a conductive film which covers the inner wall of the said through-hole, The multilayer circuit board of Additional remark 2 characterized by the above-mentioned.
(Supplementary note 4) Any one of Supplementary notes 1 to 3, wherein the first insulating layer and the second insulating layer are formed of a polyimide resin having no glass transition temperature within a use temperature range. The multilayer circuit board according to one item.
(Additional remark 5) The said 1st insulating layer and the said 2nd insulating layer have the same thermal expansion coefficient as the said 1st conductive layer and the said 2nd conductive layer, The multilayer of Additional remark 4 characterized by the above-mentioned Circuit board.
(Supplementary note 6) The multilayer circuit board according to any one of Supplementary notes 1 to 5, wherein the through hole is formed with the pair of signal lines interposed therebetween.
(Appendix 7) A step of forming a pair of signal lines on the first insulating layer formed of resin, a step of disposing a second insulating layer formed of resin on the signal line, Forming a through hole penetrating from the first conductive layer formed on the lower surface of the first insulating layer to the second conductive layer formed on the upper surface of the second insulating layer. A method of manufacturing a multilayer circuit board.
(Additional remark 8) It has the process of covering the inner wall of the said through-hole with a electrically conductive film, The manufacturing method of the multilayer circuit board of Additional remark 7 characterized by the above-mentioned.
(Additional remark 9) The 1st interlayer insulation layer containing uncured resin is arranged under the 1st conductive layer, and the 2nd interlayer insulation layer containing uncured resin on the 2nd conductive layer When the first interlayer insulating layer is bonded to the first conductive layer and the second interlayer insulating layer is bonded to the second conductive layer, the first interlayer insulating layer and the The method for manufacturing a multilayer circuit board according to appendix 7 or appendix 8, further comprising a step of embedding a resin of the second interlayer insulating layer in the through hole.
(Appendix 10) The step of bonding the first interlayer insulating layer to the first conductive layer and the second interlayer insulating layer to the second conductive layer includes melting uncured resin and The method for manufacturing a multilayer circuit board according to appendix 9, wherein the method includes a step of embedding in the through hole and a step of curing the molten resin.

1 Insulating layer (first insulating layer, second insulating layer)
2A copper foil (second conductor layer)
2B Copper foil (first conductive layer)
10 Wiring pattern (signal line)
41, 61 Three-layer wiring board 42 Through-hole 43A Resin 51, 65 Multilayer circuit board 62 Conductive film

Claims (2)

A pair of signal lines;
A first insulating layer formed below the signal lines by using a resin material having no glass fiber fabric,
A first conductive layer formed under the first insulating layer and connected to a power source or a ground;
A second insulating layer formed above the signal line by using a resin material having no glass fiber fabric,
A second conductive layer formed on the second insulating layer and connected to a power source or a ground;
A plurality of through holes penetrating from the first conductive layer to the second conductive layer at positions sandwiching a pair of the signal lines, and having no conductive film on the inner wall ;
A resin that covers the first conductive layer and the second conductive layer and is embedded in the through hole;
A multilayer circuit board comprising: Forming a pair of signal lines on the first insulating layer formed of a resin having no glass fiber fabric ;
Disposing a second insulating layer formed of a resin not having a glass fiber fabric on the signal line;
Penetrating from the first conductive layer formed on the lower surface of the first insulating layer to the second conductive layer formed on the upper surface of the second insulating layer at a position between the pair of signal lines , a step of forming a plurality of transmural holes having no conductive film on the inner wall,
Covering the first conductive layer and the second conductive layer and embedding a resin in the through hole;
A method for manufacturing a multilayer circuit board comprising:

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