JP2005019601A - Multilayer circuit board and its producing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer circuit board in which the occurrence of a short circuit between conductor patterns is suppressed, and to provide its producing process. <P>SOLUTION: The multilayer circuit board 100 is produced by laminating two sheets of conductor pattern films 9a and 10b. A hole 3h having a rear surface connection land 2ar as its bottom is formed in the conductor pattern film 9a and filled with a conductive paste. A surface connection land 20bf consisting of a central part 20bfc and a peripheral separation part 20bfs arranged around the central part while being spaced apart therefrom is provided on the other conductor pattern film 10b. The rear surface connection land 2ar and the surface connection land 20bf are interconnected through a connection conductor 3b formed by sintering the conductive paste. Although tin contained in the conductive paste melts at the time of sintering and begins to flow, it is captured by the peripheral separation part 20bfs and absorbed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer circuit board and a method for manufacturing the same.
[0002]
[Prior art]
A multilayer circuit board manufactured by laminating a plurality of conductor pattern films having a conductor pattern formed on one surface of a resin film is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-38464 (Patent Document 1). Yes.
[0003]
[Patent Document 1] JP 2000-38464 A
[0004]
[Problems to be solved by the invention]
In the above method for manufacturing a multilayer circuit board, there is a possibility that a conductor pattern film adjacent at the time of lamination is displaced from a predetermined position. FIGS. 6A and 6B show such a state. FIG. 6A is a schematic cross-sectional view showing a part of the multilayer circuit board that has been displaced, and FIG. 6B is an enlarged view of the portion surrounded by the alternate long and short dash line in FIG. is there.
[0005]
A multilayer circuit board 90 shown in FIG. 6A is formed by laminating conductor patterns 9a to 9c in which conductor patterns 2a to 2c are formed on one surface of resin films 1a to 1c and bonding them together. It is a multilayer circuit board. The resin films 1a to 1c are made of thermoplastic resin, and the conductor patterns 2a to 2c are made of copper foil.
[0006]
6A and 6B, the connection conductor 3b is an interlayer conductor that interconnects the conductor patterns 2a to 2c with each other. In the multilayer circuit board 90 of FIG. 6A, the holes 3h having the conductor patterns 2a to 2c as the bottoms are formed, and the conductive paste filled in the holes 3h is sintered to form the connection conductors 3b. . As the conductive paste, a conductive paste using silver and tin as conductive fillers is used. When this conductive paste is sintered, a silver-tin alloy is formed. Moreover, tin, which is one of the constituent components of the conductive paste, diffuses into the copper foil, whereby the conductor pattern and the connection conductor 3b, which is a silver-tin alloy, are connected to obtain conductivity.
[0007]
In FIG. 6 (a), the portion surrounded by the alternate long and short dash line is a connection land 2ar of one component part of the conductor pattern in which the adjacent conductor pattern films 9a and 9b are displaced when stacked and connected via the connection conductor 3b. , 2bf are misaligned with each other.
[0008]
In the enlarged view shown in FIG. 6B, reference numerals 2bfd and 2bd are layers formed by diffusing the tin, which is a constituent component of the conductive paste, into a conductive pattern 2bf, 2b made of copper foil by liquefaction by heating. is there. Reference numeral 3s denotes an outflow layer formed by flowing out of liquefied tin because the hole 3h protrudes from the connection land 2bf due to the displacement. When the outflow layer 3s is formed, as shown in FIGS. 6A and 6B, a short circuit failure is likely to occur between the connection land 2bf and the adjacent conductor pattern 2b. The incidence of such short-circuit defects increases as the fine-pitch multilayer circuit board is obtained.
[0009]
Therefore, an object of the present invention is to provide a multilayer circuit board in which the occurrence of short circuit defects is suppressed and a method for manufacturing the same.
[0010]
[Means for Solving the Problems]
The invention according to claim 1 is a multilayer circuit board in which a plurality of conductor pattern films each having a conductor pattern formed on one surface of a resin film are laminated and bonded to each other. In the two adjacent conductor pattern films, in one conductor pattern film, a hole with the bottom surface of the back surface connection land is formed in the back surface connection land, which is a constituent part of the conductor pattern. The other conductive pattern film is filled with the paste, and the surface connection land which is one component part of the conductor pattern is provided, and the surface connection land is arranged apart from the central portion and the central portion. The conductive patterns of the two adjacent conductive pattern films laminated on the back surface connection land and the front surface connection land. Te, via a connecting conductor in which the conductive paste is formed by sintering, is characterized in that formed by connecting each other.
[0011]
According to this, in the adjacent conductor pattern film, the other front surface connection land connected by the conductive paste to one back surface connection land is not only the central portion, but the peripheral separation portion is separated around it. Arranged. The surface connection land has a surface area larger than that of the surface connection land in which the central portion and the peripheral separation portion are integrated with each other so as to form a cut surface. By increasing the surface area in this way, the diffusion absorption capability when the components of the conductive paste are liquefied and flow out to the surroundings is enhanced. In addition, the peripheral separation part arranged around the center part blocks the flow when the opening part of the hole with the back surface connection land as the bottom protrudes from the center part and the component of the conductive paste filled in the hole flows out. Also plays a role to stop. Therefore, in the said multilayer circuit board, even if adjacent conductor pattern film raise | generates position shift at the time of lamination | stacking, the short circuit defect by the flowing out of an electrically conductive paste component is suppressed.
[0012]
The invention according to claim 2 is characterized in that the peripheral separation portion surrounds the central portion. By disposing the peripheral separation portion so as to surround the central portion, the effect of blocking the flow of the conductive paste component by the peripheral separation portion becomes complete. Accordingly, it is possible to further suppress a short circuit failure due to the flow of the conductive paste component.
[0013]
The invention according to claim 3 is a multilayer circuit board in which a plurality of conductor pattern films each having a conductor pattern formed on one surface of a resin film are laminated and bonded to each other. In the two adjacent conductor pattern films, in one conductor pattern film, a hole with the bottom surface of the back surface connection land is formed in the back surface connection land, which is a constituent part of the conductor pattern. The other conductive pattern film is filled with a paste, and a surface connection land, which is one constituent part of the conductor pattern, is provided on the surface of the surface connection land. The conductor patterns of the matching conductor pattern films are formed by sintering the conductive paste in the back connection land and the front connection land. Via conductors, it is characterized in that formed by connecting each other.
[0014]
By forming the concave portion on the surface of the surface connection land, the surface area can be increased as compared with the surface connection land in which the concave portion is not formed as in the case of the peripheral separation portion. Accordingly, in this case as well, the diffusion absorption capability when the components of the conductive paste are liquefied and flow out to the surroundings is enhanced. Therefore, even in the multilayer circuit board in which the concave portion is formed on the surface of the surface connection land, short circuit failure due to the flow of the conductive paste component is suppressed even when the adjacent conductor pattern film is displaced during lamination.
[0015]
The invention according to claim 4 is a multilayer circuit board in which a plurality of conductor pattern films each having a conductor pattern formed on one surface of a resin film are laminated and bonded to each other. In the two adjacent conductor pattern films, in one conductor pattern film, a hole with the bottom surface of the back surface connection land is formed in the back surface connection land, which is a constituent part of the conductor pattern. The paste is filled, and the other conductor pattern film is provided with a surface connection land which is one constituent part of the conductor pattern, and an uneven portion is formed on the surface of the surface connection land by a process of roughening the surface. The conductive patterns of two adjacent conductive pattern films formed on the back surface connection land and the front surface connection land are in the conductive page. Via a connection conductor bets are formed by sintering, it is characterized in that formed by connecting each other.
[0016]
Also in this case, the surface area can be increased by forming the concavo-convex portion on the surface of the surface connection land by the process of roughening the surface, as in the case of forming the concave portion. Accordingly, in this case as well, the diffusion absorption capability when the component of the conductive paste liquefies and flows out to the surroundings is enhanced, and short circuit failure due to the flow of the conductive paste component is suppressed.
[0017]
As described in claim 5, the resin film is preferably a thermoplastic resin. Thereby, the laminated | stacked several conductor pattern film can be bonded together by heating and pressurization, and since manufacturing cost can be reduced, it can be set as an inexpensive multilayer circuit board.
[0018]
Preferably, the conductor pattern is made of a metal foil. Thereby, since the hole having the bottom of the conductor pattern made of metal foil can be easily and accurately formed by laser processing, the manufacturing cost can be reduced and an inexpensive multilayer circuit board can be obtained.
[0019]
As described in claim 7, the metal foil is preferably a copper foil. Since the copper foil has high conductivity and high strength, it becomes the bottom of the hole filled with the conductive paste, and is optimal for the conductor pattern of the multilayer circuit board connected between the layers.
[0020]
As described in claim 8, it is preferable that the conductive paste has a conductive filler made of silver and tin. According to this, the conductive paste can be sintered at a low temperature by including the conductive filler of tin, and therefore the conductive paste is sintered simultaneously with the bonding of the conductor pattern film by the heating and pressurization. Can do. For this reason, manufacturing cost can be reduced and an inexpensive multilayer circuit board can be obtained. Moreover, the connection conductor which has high electroconductivity can be formed by including a silver conductive filler.
[0021]
The invention according to any one of claims 9 to 21 includes a resin material that defines a shape as a substrate, and a plurality of conductors that are arranged in multiple layers in the resin material by being supported by the resin material, and are formed by electric conductors. The present invention relates to a multilayer circuit board having a pattern and an interlayer conductor that is arranged in the resin material and connects the two conductor patterns located in different layers. In the multilayer circuit boards according to the ninth to twenty-first aspects, an absorption auxiliary portion for assisting absorption of the electric conductor component is formed in the land portion, or a capturing portion for capturing the molten metal component is provided in the land portion. It is characterized in that it is formed in the peripheral part. By this absorption assisting part or capturing part,
Even if misalignment occurs during the production of the multilayer circuit board, short circuit failure due to the flow of the electrical conductor component or the molten metal component is suppressed. In addition, about the effect of the invention of these 9th-21st, it is the same as that of the effect explained in full detail in the invention of the 1st-8th, The detailed description is abbreviate | omitted.
[0022]
The invention described in claims 22 to 24 is an invention related to a method for manufacturing a multilayer circuit board described in claims 1 to 21. Since the effects of the multilayer circuit board obtained by the manufacturing method of the present invention have been described above, description thereof will be omitted. It is possible to carry out all at once by heating once, and the manufacturing cost of the multilayer circuit board can be reduced.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a multilayer circuit board of the present invention will be described with reference to the drawings.
[0024]
(First embodiment)
1A and 1B are schematic cross-sectional views showing a multilayer circuit board and a method for manufacturing the same in the present embodiment. FIG. 1A is a diagram showing a laminated arrangement of conductor pattern films 9a, 10b, and 10c before bonding, and FIG. 1B is a diagram showing a multilayer circuit board 100 after bonding. The multilayer circuit board 100 of FIG. 1B is manufactured by laminating the conductor pattern films 9a, 10b, and 10c of FIG. 1A and laminating them as shown in the figure. In FIGS. 1A and 1B, only three adjacent conductive pattern films 9a, 10b, and 10c that are bonded to each other are shown for the sake of simplicity. In the multilayer circuit board 100 of FIG. 1B, the same parts as those of the conventional multilayer circuit board 90 shown in FIG.
[0025]
As shown to Fig.1 (a), in each conductor pattern film 9a, 10b, 10c, conductor pattern 2a, 20b, 20c which consists of copper foil is formed on one side of resin film 1a-1c which consists of thermoplastic resins. Is formed.
[0026]
In two adjacent conductor pattern films (for example, 9a and 10b) to be laminated, a back surface connection land (for example, a part of the conductor pattern 2a having a partially widened wiring) is formed on one conductor pattern film 9a. 2ar) is provided. Furthermore, the resin film 1a of the conductor pattern film 9a is formed with a hole 3h with the back connection land 2ar at the bottom by laser processing, and the hole 3h is filled with a conductive paste 3a serving as a connection conductor (interlayer conductor). Yes. The conductor pattern film 9a in FIG. 1 (a) is the same as the conductor pattern film shown in FIG. 6 (a), and the conductive paste 3a filled in the holes 3h is made of silver and tin as conductive fillers. A conductive paste is used.
[0027]
The other conductor pattern film 10b is provided with a surface connection land (for example, 20bf) in which the width of the wiring is partially increased as one component of the conductor pattern 20b. The surface connection land 20bf is composed of a central portion 20bfc and a peripheral separation portion 20bfs arranged apart from each other around the central portion 20bfc. The surface connection land 20bf shown in FIG. 1 (a) is separated from the surface connection land 2bf of FIG. 6 (a) in which the central portion and the peripheral separation portion are integrated, and the cut surface is formed. The surface area is large.
[0028]
2 (a) to 2 (f) are top views showing various planar pattern shapes of the surface connection land 20bf shown in FIGS. 1 (a) and 1 (b).
[0029]
In FIG. 2A, a circular surface connection land 21bf including a central portion 21bfc and a peripheral separation portion 21bfs surrounding the central portion 21bfc exists independently. In the surface connection land 22bf shown in FIG. 2B, a circular surface connection land 22bf including a central portion 22bfc and a peripheral separation portion 22bfs surrounding the central portion 22bfc is connected to the wiring portion 22bfk. In FIG. 2C, a circular surface connection land 23bf including a central portion 23bfc and four peripheral separation portions 23bfs spaced apart from each other is present alone. In the surface connection land 24bf of FIG. 2D, a circular surface connection land 24bf composed of a central portion 24bfc and four peripheral separation portions 24bfs spaced apart from each other is connected to the wiring portion 24bfk. is doing. In FIG. 2E, a rectangular surface connection land 25bf including a central portion 25bfc and a peripheral separation portion 25bfs surrounding the central portion 25bfc exists independently. In the surface connection land 26bf of FIG. 2 (f), a rectangular surface connection land 26bf including a central portion 26bfc and a peripheral separation portion 26bfs surrounding the central portion 26bfc is connected to the wiring portion 26bfk.
[0030]
The surface connection land 20bf shown in FIGS. 1 (a) and 1 (b) may have any pattern shape shown in FIGS. 2 (a) to 2 (f). Further, as shown in FIGS. 2A to 2F, the surface connection land 20bf is not limited to a circular shape or a rectangular shape as shown in FIGS. It only has to be.
[0031]
As shown in FIG. 1A, the conductor pattern film 9a in which the hole 3h is filled with the conductive paste 3a and the conductor pattern film 10b in which the surface connection land 20bf is provided include the opening of the hole 3h and the surface connection land. It is laminated so that 20bf faces each other.
[0032]
Next, the conductor pattern films 9a, 10b, and 10c laminated as shown in FIG. 1 (a) are inserted between a pair of hot press plates in which heaters are embedded via an adhesion prevention film, a buffer material, etc., and heated. Press. Through this heating and pressurizing step, the thermoplastic resin films 1a to 1c of FIG. 1A are at least partially melted and joined together to form the resin base material 1 of FIG. 1B. By this heating and pressurizing step, the conductive paste 3a containing silver and tin as conductive fillers in FIG. 1 (a) is sintered, and the connection conductor (interlayer conductor) 3b in FIG. Become. In this manner, the conductor pattern films 9a, 10b, and 10c are bonded to each other, and the back surface connection land 20ar is connected to the front surface connection land 20bf via the connection conductor 3b. The multilayer circuit board bonded by the above heating and pressurization is taken out from the hot press plate, and the multilayer circuit board 100 shown in FIG. 1B is manufactured.
[0033]
In FIG. 1 (b), the portion surrounded by the alternate long and short dash line causes the adjacent conductor pattern films 9a and 10b to be displaced when stacked, and the back surface connection land 2ar and the surface connection land 20bf connected via the connection conductor 3b. It is the part which has shifted mutually. FIG. 3 shows an enlarged view thereof. In addition, in the enlarged view of FIG. 3, reference numerals 20bfcd and 20bfsd denote the central portion 20bfc and the peripheral separation portion 20bfs of the surface connection land 20bf made of copper foil, respectively, by which tin which is a constituent component of the conductive paste 3a is liquefied by heating. It is a layer formed by diffusing.
[0034]
In the multilayer circuit board 100 shown in FIG. 1B, the surface connection land 20bf is separated into the central portion 20bfc and the peripheral separation portion 20bfs, and the surface area is larger than that of the surface connection land 2bf shown in FIG. . For this reason, even when the adjacent conductor pattern films 9a and 10b are displaced at the time of lamination, and the tin component of the conductive paste 3a is liquefied and flows out to the surroundings, the diffusion absorption capability is increased by increasing the surface area. Is increased, and the outflow of the tin component is suppressed. In other words, the peripheral separation portion 20bfs functions as an absorption auxiliary portion that is formed in the land portion 20bf and assists absorption of the electric conductor component. Further, in the peripheral separation part 20bfs arranged around the central part 20bfc, the opening part of the hole 3h with the back surface connection land 2ar as the bottom protrudes from the central part 20bfc, and the tin component of the conductive paste 3a filled in the hole 3h It also plays a role of blocking the flow when it flows out. Furthermore, the tin component of the conductive paste 3a that has entered between the central portion 20bfc and the peripheral separation portion 20bfs flows into an empty space so as to embed the space between the central portion 20bfc and the peripheral separation portion 20bfs due to capillary action. In this space, copper and tin will form an alloy. In other words, the peripheral separation unit 20bfs functions as a capturing unit that captures a molten metal component. As a result, even if the adjacent conductor pattern films 9a and 10b are misaligned during lamination in the multilayer circuit board 100 of FIG. 1B, as shown in FIG. Outflow layer 3s is not formed, and short circuit failure is suppressed.
[0035]
In the surface connection land 20bf composed of the central portion 20bfc and the peripheral separation portion 20bfs in FIGS. 1A and 1B, the improvement of the tin component diffusion / absorption ability by the increase in the surface area is any of FIGS. 2A to 2F. Even those with a pattern shape of On the other hand, the flow blocking effect of the tin component by the peripheral separation portion 20bfs arranged around the central portion 20bfc of FIGS. 1 (a) and 1 (b) will be described with reference to FIGS. 2 (a), (b), (e), ( The surface connection lands 21bf, 22bf, 25bf, and 26bf of f) are preferable. 2 (a), (b), (e), and (f), the peripheral separation portions 21bfs, 22bfs, 25bfs, and 26bfs surround the central portions 21bfc, 22bfc, 25bfc, and 26bfc, so The effect of blocking the flow of the conductive paste component by the separating portions 21bfs, 22bfs, 25bfs, and 26bfs is completed. Therefore, short circuit failure due to the flow of the conductive paste component can be further suppressed.
[0036]
(Second Embodiment)
The multilayer circuit board of this embodiment has a surface connection land having a recess formed on the surface.
[0037]
FIG. 4 is a schematic cross-sectional view showing the multilayer circuit board 101 after bonding in the present embodiment. In FIG. 4, for the sake of simplicity, only two adjacent conductor pattern films 9a and 11b bonded to each other are shown. Moreover, in FIG. 4, the case where the conductor pattern film 11b has shifted | deviated to the right with respect to the conductor pattern film 9a is shown. In the multilayer circuit board 101 of FIG. 4, the same parts as those of the conventional multilayer circuit board 90 shown in FIG.
[0038]
In the multilayer circuit board 101 of FIG. 4, one of the laminated conductor pattern films 9a is the same as the conductor pattern film shown in FIG. 6 (a), and the back surface connection land 2ar and the inside of the hole 3h having the bottom as the bottom connection land 2ar. The conductive pattern film is filled with the conductive paste 3a.
[0039]
On the other hand, the surface connection land 27bf of the other conductor pattern film 11b is different from the surface connection land 2bf of the conductor pattern film shown in FIG. In FIG. 4, reference numerals 2 ard and 27 bfd are layers formed by diffusing the tin, which is a constituent component of the conductive paste 3 a, into liquid by heating and diffusing to the back surface connection land 2 ar and the surface connection land 27 bf respectively. is there.
[0040]
Due to the formation of the recess 27bfh, the surface connection land 27bf shown in FIG. 4 has a larger surface area than the conventional surface connection land 2bf shown in FIG. 6 (a). Therefore, also in the surface connection land 27bf of FIG. 4, the diffusion absorption capacity of the tin component is enhanced. In other words, the concave portion 27bfh functions as an absorption auxiliary portion that is formed in the land portion 27bf and assists the absorption of the electric conductor component. Further, the concave portion 27bfh formed in the land portion 27bf also functions as a capturing portion that captures a molten metal component. For this reason, even when the adjacent conductor pattern films 9a and 11b are displaced during lamination and the tin component of the conductive paste 3a is about to flow out to the surroundings, the tin component is diffused and absorbed in the concave portion having an increased surface area. Outflow is suppressed. Thereby, in the multilayer circuit board 101 shown in FIG. 4, the short circuit defect by the flow of the component of the electrically conductive paste 3a is suppressed similarly to the multilayer circuit board of 1st Embodiment.
[0041]
(Third embodiment)
The multilayer circuit board according to the present embodiment has a surface connection land having a concavo-convex portion (rough surface portion) formed on the surface by a process of roughening the surface.
[0042]
5A to 5D are views showing surface connection lands in the multilayer circuit board of the present embodiment. 5A to 5D, only a top view and a cross-sectional view of the conductor pattern films 12b to 15b having the surface connection lands 28bf to 31bf are shown for simplification.
[0043]
In the conductor pattern film 12b of FIG. 5A, the circular surface connection land 28bf exists independently. In the conductor pattern film 13b of FIG. 5B, a circular surface connection land 29bf exists in connection with the wiring portion 29bfk. In the conductor pattern film 14b shown in FIG. 5C, a circular surface connection land 30bf including a central portion 30bfc and a double peripheral separation portion 30bfs surrounding the central portion 30bfc exists independently. In the conductor pattern film 15b shown in FIG. 5D, a circular surface connection land 31bf including a central portion 31bfc and a double peripheral separation portion 31bfs surrounding the central portion 31bfc is connected to the wiring portion 31bfk.
[0044]
In the surface connection lands 28bf to 31bf in FIGS. 5A to 5D, unlike the surface connection lands 2bf of the conductor pattern film shown in FIG. (Rough surface portion) 28bfg to 31bfg are formed.
[0045]
Since the uneven portions 28bfg to 31bfg are formed, the surface connection lands 28bf to 31bf shown in FIGS. 5A to 5D also have a larger surface area than the surface connection lands 2bf shown in FIG. Yes. Therefore, in this case as well, the ability to diffuse and absorb the tin component of the conductive paste is enhanced. In other words, the concavo-convex portions (rough surface portions) 28bfg to 31bfg function as absorption assisting portions that are formed in the land portions 28bf to 31bf and assist the absorption of the electric conductor component. As a result, when the tin component is about to flow out to the surroundings due to misalignment during lamination, it is diffused and absorbed by the concavo-convex portions 28bfg to 31bfg having an increased surface area, thereby suppressing the flow out. Thereby, in the multilayer circuit board having the surface connection lands 28bf to 31bf shown in FIGS. 5A to 5D, the short circuit failure due to the flow of the components of the conductive paste is suppressed as in the multilayer circuit board of the second embodiment. Is done.
[0046]
(Other embodiments)
The present invention is also applied to a multilayer circuit board in which a plurality of conductor pattern films each having a conductor pattern formed on a resin film made of a thermosetting resin are laminated and bonded together using an adhesive. can do. In each of the above embodiments, an example in which the conductor pattern is made of a copper foil has been shown. However, the conductive pattern may be a metal foil such as silver, gold, or aluminum, or a metal layer other than the metal foil. Further, in each of the above embodiments, an example in which the conductive paste has a conductive filler made of silver and tin has been shown. However, any metal can be used as long as it is a conductive paste that can be sintered at a relatively low temperature. It may be a conductive paste used as a conductive filler.
[0047]
According to the embodiment described above, the multilayer circuit board has a shape in which a plurality of conductor patterns are arranged in multiple layers in a resin base material as a resin material defining the shape. In the resin material, a plurality of interlayer connection conductors are arranged, and two conductor patterns located in different layers are connected by the respective interlayer connection conductors. Connection lands for connecting the interlayer connection conductors are formed in the plurality of conductor patterns. Among these connection land portions, at least the connection land portion located in the inner layer is formed with an absorption assisting portion in which the absorbability of molten tin is higher than that of the central portion. The connection land portion may be formed with a capturing portion that dams and captures molten tin at the periphery thereof. It is desirable that this trapping portion also serves as an absorption assisting portion in order to absorb the tin trapped therein into the conductor pattern. In one embodiment, a slit penetrating the connection land is formed in the peripheral portion of the connection land. This slit separates the connection land into a central part and a peripheral part surrounding it, and forms a capturing part and an absorption assisting part. In another embodiment, the absorption assisting part or the capturing part is formed by a concave part or a rough surface part formed in the peripheral part of the connection land.
[0048]
According to the above embodiment, a plurality of conductor pattern films each having a conductor pattern formed on one surface of a resin film are laminated and bonded to each other, and are adjacent conductor patterns. Provided are a multilayer circuit board and a method for manufacturing the same, in which the occurrence of short-circuit failure is suppressed even when the film is displaced during lamination.
[Brief description of the drawings]
1A and 1B are cross-sectional views showing a multilayer circuit board and a manufacturing method thereof according to a first embodiment of the present invention, wherein FIG. 1A is a view showing a stacked arrangement before bonding, and FIG. It is a figure which shows this multilayer circuit board.
FIGS. 2A to 2F are top views showing various planar pattern shapes of the surface connection lands shown in FIGS. 1A and 1B. FIGS.
FIG. 3 is an enlarged view of a portion surrounded by an alternate long and short dash line in FIG.
FIG. 4 is a schematic cross-sectional view showing a multilayer circuit board in a second embodiment of the present invention.
FIGS. 5A to 5D are diagrams showing surface connection lands in a multilayer circuit board according to a third embodiment of the present invention. FIGS.
FIG. 6A is a schematic cross-sectional view showing a conventional multilayer circuit board that has been displaced, and FIG. 6B is an enlarged view of a portion surrounded by a dashed line in FIG.
[Explanation of symbols]
90,100 to 101 multilayer circuit board
9a, 9b-15b, 9c, 10c Conductor pattern film
1a, 1b, 1c Resin film
1 Resin base material
2a, 2b, 20b, 27b, 2c, 20c Conductor pattern
2ar back connection land
2bf, 20bf to 27bf Surface connection land
20bfc to 26bfc, 30bfc, 31bfc center
20bfs-26bfs, 30bfs, 31bfs Periphery separation part
27bfh recess
28 bfg to 31 bfg
3h hole
3a Conductive paste
3b Connecting conductor (interlayer conductor)

Claims (24)

A multilayer circuit board in which a plurality of conductor pattern films in which a conductor pattern is formed on one surface of a resin film are laminated and bonded together,
In the two adjacent conductor pattern films laminated,
In one conductor pattern film, in the back surface connection land which is one constituent part of the conductor pattern, a hole with the back surface connection land as the bottom is formed, and the conductive paste is filled in the hole,
The other conductor pattern film is provided with a surface connection land that is one component of the conductor pattern,
The surface connection land is composed of a central part and a peripheral separation part arranged around the central part,
The conductor patterns of the two adjacent conductor pattern films to be laminated are connected to each other via a connection conductor formed by sintering the conductive paste in the back surface connection land and the surface connection land. A multilayer circuit board characterized by the above. The multilayer circuit board according to claim 1, wherein the peripheral separation portion surrounds the central portion. A multilayer circuit board in which a plurality of conductor pattern films in which a conductor pattern is formed on one surface of a resin film are laminated and bonded together,
In the two adjacent conductor pattern films laminated,
In one conductor pattern film, in the back surface connection land which is one constituent part of the conductor pattern, a hole with the back surface connection land as the bottom is formed, and the conductive paste is filled in the hole,
The other conductor pattern film is provided with a surface connection land that is one component of the conductor pattern,
A recess is formed on the surface of the surface connection land,
The conductor patterns of the two adjacent conductor pattern films to be laminated are connected to each other via a connection conductor formed by sintering the conductive paste in the back surface connection land and the surface connection land. A multilayer circuit board characterized by the above. A multilayer circuit board in which a plurality of conductor pattern films in which a conductor pattern is formed on one surface of a resin film are laminated and bonded together,
In the two adjacent conductor pattern films laminated,
In one conductor pattern film, in the back surface connection land which is one constituent part of the conductor pattern, a hole with the back surface connection land as the bottom is formed, and the conductive paste is filled in the hole,
The other conductor pattern film is provided with a surface connection land that is one component of the conductor pattern,
An uneven portion is formed on the surface of the surface connection land by a process of roughening the surface,
The conductor patterns of the two adjacent conductor pattern films to be laminated are connected to each other via a connection conductor formed by sintering the conductive paste in the back surface connection land and the surface connection land. A multilayer circuit board characterized by the above. The multilayer circuit board according to claim 1, wherein the resin film is made of a thermoplastic resin. The multilayer circuit board according to claim 1, wherein the conductor pattern is made of a metal foil. The multilayer circuit board according to claim 6, wherein the metal foil is a copper foil. The multilayer circuit board according to claim 1, wherein the conductive paste has a conductive filler made of silver and tin. A resin material that defines the shape of the substrate;
A plurality of conductor patterns arranged in multiple layers within the resin material by being supported by the resin material, and formed by electrical conductors;
A multilayer circuit board having an interlayer conductor disposed in the resin material and connecting two conductor patterns located in different layers;
The interlayer conductor includes an electrical conductor component that is easily absorbed by the electrical conductor forming the conductor pattern,
The conductor pattern has a land portion connected to the interlayer conductor, and further, an absorption auxiliary portion for assisting absorption of the electric conductor component is formed in the land portion. substrate. The multilayer circuit board according to claim 9, wherein
The multilayer circuit board according to claim 1, wherein the absorption assisting part is formed in a peripheral part of the land part. The multilayer circuit board according to claim 10, wherein
The land portion includes a main portion formed with a predetermined area, and a peripheral portion that is disposed outside the main portion, has a relatively small area, and is formed at least partially away from the main portion. A multilayer circuit board, wherein the absorption assisting portion is formed by the peripheral portion. The multilayer circuit board according to claim 10, wherein
The multilayer circuit board, wherein the absorption assisting portion is formed by a recess formed in the land portion. The multilayer circuit board according to claim 10, wherein
The multilayer circuit board, wherein the absorption assisting portion is formed by a rough surface portion formed on a surface of the land portion. The multilayer circuit board according to any one of claims 9 to 13,
It has a plurality of interlayer conductors including the interlayer conductor, and among the two land parts connected to the interlayer conductor arranged on the outermost surface of them, only the land part arranged on the inner layer side absorbs the absorption A multilayer circuit board having an auxiliary portion formed thereon. A resin material that defines the shape of the substrate;
A plurality of conductor patterns arranged in multiple layers within the resin material by being supported by the resin material, and formed by electrical conductors;
A multilayer circuit board having an interlayer conductor disposed in the resin material and connecting two conductor patterns located in different layers;
The interlayer conductor includes a metal component that melts in the manufacturing process of the multilayer circuit board,
The multilayer circuit board according to claim 1, wherein the conductor pattern has a land portion connected to the interlayer conductor, and the land portion has a capturing portion for capturing the molten metal component at a peripheral portion thereof. The multilayer circuit board according to claim 15, wherein
The multilayer circuit board according to claim 1, wherein the capturing part has a slit formed through the land part. The multilayer circuit board according to claim 15, wherein
The multi-layer circuit board, wherein the capturing part has a recess formed in the land part. The multilayer circuit board according to any one of claims 15 to 17,
It has a plurality of interlayer conductors including the interlayer conductor, and among the two land parts connected to the interlayer conductor arranged most on the surface layer among them, the trapping is performed only on the land part arranged on the inner layer side. A multilayer circuit board in which a portion is formed. The multilayer circuit board according to any one of claims 9 to 18, wherein the resin material is a thermoplastic resin. 20. The multilayer circuit board according to claim 9, wherein the conductor pattern includes copper. 21. The multilayer circuit board according to claim 20, wherein the electrical conductor component contained in the interlayer conductor is tin. In the method of manufacturing a multilayer circuit board in which a plurality of conductor patterns are arranged in a multilayer in a resin material, and the two conductor patterns located in different layers are connected via an interlayer conductor,
The conductor pattern forms a land portion that easily captures a partial component of the interlayer conductor in the peripheral portion from the central portion,
A mixture for forming the interlayer conductor is placed in contact with the land portion;
Heating the land portion and the mixture in a state where the mixture and the land portion are in contact with each other;
The heating causes some components of the mixture to melt,
While the component is melted by the heating, the interlayer conductor is formed from the mixture while capturing the melted component in the peripheral portion of the land portion, and further between the land portion and the interlayer conductor. A method of manufacturing a multilayer circuit board, characterized by forming an electrical connection. In the manufacturing method of the multilayer circuit board according to claim 22,
The resin material is a thermoplastic resin,
The land portion is formed by arranging the conductor pattern on the resin material film,
The mixture is disposed in contact with the land portion by filling the holes formed in the film and further laminating the plurality of films.
A method of manufacturing a multilayer circuit board, wherein the plurality of films are bonded by the heating. In the manufacturing method of the multilayer circuit board according to claim 22 or 23,
The film is pressurized simultaneously with the heating,
The component that melts by heating is tin,
In the mixture, tin is contained to such an extent that the molten tin flows out from the contact portion between the mixture and the land portion,
During the period in which the tin is melted by the heating, the molten tin is captured by the peripheral portion of the land portion located outside the contact portion between the mixture and the land portion. A method for manufacturing a substrate.

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