JP2014222721A - Resin multilayer substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin multilayer substrate which can improve reliability of joint at a joining part between a conductor pattern and a via conductor.SOLUTION: A resin multilayer substrate 101 formed by lamination of a plurality of resin layers 2, which each have a principal surface 2a and are composed of a thermoplastic resin comprises: a via conductor 6a which pierces one layer among the resin layers 2 in a thickness direction; a conductor pattern 7a which is formed on the principal surface 2a of the resin layers 2 in which the via conductor 6a is formed and which is connected to the via conductor 6a; and a hard member 8 which has hardness relatively larger than that of the resin layer 2 and is built into the resin multilayer substrate 101. The via conductor 6a is arranged near an outer edge 8d of the hard member 8 when viewed in a lamination direction of the plurality of resin layers 2. The conductor pattern 7a has an enlarged part 9 having an area enlarged on the side departing from the hard member 8 when viewed in the lamination direction.

Description

  The present invention relates to a resin multilayer substrate.

  Regarding a resin multilayer substrate, there has been disclosed a configuration in which a multilayer substrate is conventionally formed of a thermoplastic resin and a metal wiring pattern, and via conductors are formed in series inside the multilayer substrate (for example, Japanese Patent Laid-Open No. 2005-136347). No. (Patent Document 1)). In addition, a technique for manufacturing a multilayer wiring board by forming a concavo-convex portion by roughening a metal foil that forms a wiring pattern, filling a bottomed via hole with conductive particles, and laminating them together is disclosed (for example, JP, 2005-129727, A (patent documents 2) reference). In addition, a conductive paste in which a hole made through the insulating film in the thickness direction is mixed with a binder made of a thermoplastic resin and a conductive material is filled, and the layers of the conductor pattern are connected to each other between layers. Discloses a structure having a glass transition point higher than that of an insulating film and a low elastic modulus at the temperature at the time of fusion (for example, see JP-A-2004-273575 (Patent Document 3)).

JP 2005-136347 A JP 2005-129727 A JP 2004-273575 A

  Generally, a resin multilayer substrate is produced by laminating resin sheets. Inside the resin multilayer substrate, a conductor pattern formed by using a conductor foil stretched on the surface of the resin sheet, and a via conductor that plays a role of electrical connection so as to penetrate each resin layer in the thickness direction Is arranged. Inside the resin multilayer substrate, there is usually a portion where both are connected in order to realize electrical connection between the conductor pattern and the via conductor.

  For example, in a flexible thermoplastic resin multilayer substrate such as thermoplastic polyimide or liquid crystal polymer, a state where a part of the substrate is bent at an arbitrary angle is maintained, or, for example, two or more in an arbitrary positional relationship In some cases, an operation of bending the substrate is performed in order to connect to the member. When the resin multilayer substrate is bent, if the bending stress is applied to or applied to the connection portion as described above, the connection performance of the connection portion between the conductor pattern and the via conductor may be deteriorated.

  Then, an object of this invention is to provide the resin multilayer substrate which can improve the reliability of joining of the junction part between a conductor pattern and a via conductor.

  To achieve the above object, a resin multilayer substrate according to the present invention is a resin multilayer substrate formed by laminating a plurality of resin layers each having a main surface and made of a thermoplastic resin, and includes a via conductor, a conductor pattern, And a hard member. The via conductor penetrates one of the resin layers in the thickness direction. The conductor pattern is formed on the main surface of the resin layer on which the via conductor is formed, and is connected to the via conductor. The hard member is a member having a relatively higher hardness than the resin layer, and is built in the resin multilayer substrate. The via conductor is disposed in the vicinity of the outer edge of the hard member when viewed in the stacking direction of the plurality of resin layers. The conductor pattern has an enlarged portion whose area is enlarged on the side away from the hard member when viewed in the stacking direction.

  ADVANTAGE OF THE INVENTION According to this invention, the reliability of joining of the junction part between a conductor pattern and a via conductor can be improved.

It is sectional drawing of the resin multilayer substrate in Embodiment 1 based on this invention. It is sectional drawing of the resin multilayer substrate which follows the II-II line | wire shown in FIG. FIG. 6 is a cross-sectional view of a first modification of the resin multilayer substrate according to the first embodiment. 6 is a cross-sectional view of a second modification of the resin multilayer substrate according to Embodiment 1. FIG. It is sectional drawing of the 3rd modification of the resin multilayer substrate of Embodiment 1. It is sectional drawing of the 4th modification of the resin multilayer substrate of Embodiment 1. It is sectional drawing of the 5th modification of the resin multilayer substrate of Embodiment 1. It is sectional drawing of the 6th modification of the resin multilayer substrate of Embodiment 1. It is sectional drawing of the 7th modification of the resin multilayer substrate of Embodiment 1. It is sectional drawing of the 8th modification of the resin multilayer substrate of Embodiment 1. It is sectional drawing of the 9th modification of the resin multilayer substrate of Embodiment 1. It is sectional drawing of the 10th modification of the resin multilayer substrate of Embodiment 1. It is sectional drawing of the 11th modification of the resin multilayer substrate of Embodiment 1. It is sectional drawing of the 12th modification of the resin multilayer substrate of Embodiment 1. It is a 1st figure which shows the relative positional relationship of a via conductor and a hard member. It is a 2nd figure which shows the relative positional relationship of a via conductor and a hard member. It is explanatory drawing of the 1st process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 2nd process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 3rd process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 4th process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 5th process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is explanatory drawing of the 6th process of the manufacturing method of the resin multilayer substrate in Embodiment 1 based on this invention. It is sectional drawing of the resin multilayer substrate in Embodiment 2 based on this invention. It is sectional drawing of the resin multilayer substrate which follows the XXIV-XXIV line | wire shown in FIG. 6 is a cross-sectional view of a modification of the resin multilayer substrate according to Embodiment 2. FIG. It is sectional drawing of the resin multilayer substrate in Embodiment 3 based on this invention. It is sectional drawing of the resin multilayer substrate in Embodiment 4 based on this invention.

(Embodiment 1)
(Constitution)
With reference to FIG. 1 and FIG. 2, the resin multilayer substrate 101 in Embodiment 1 based on this invention is demonstrated. The resin multilayer substrate 101 in the present embodiment includes a laminate 1 in which a plurality of resin layers 2 are laminated and integrated. The resin multilayer substrate 101 is formed by laminating a plurality of resin layers 2. The plurality of resin layers 2 are sequentially laminated in the thickness direction of each resin layer 2, and the thickness direction of each resin layer 2 and the thickness direction of the resin multilayer substrate 101 are both in the vertical direction in the cross-sectional view shown in FIG. 1. It is. The resin layer 2 is formed of a thermoplastic resin material such as thermoplastic polyimide or liquid crystal polymer. The resin multilayer substrate 101 has a first main surface 3 that is one main surface and a second main surface 4 that is the other main surface opposite to the first main surface 3. Each resin layer 2 has a main surface 2a.

  The resin multilayer substrate 101 includes a plurality of conductor patterns 7 and a plurality of via conductors 6 therein. The conductor pattern 7 is disposed at the interface between the plurality of resin layers 2. The via conductor 6 penetrates at least one of the resin layers 2 in the thickness direction, extends in the thickness direction of the resin layer 2, and is connected to the conductor pattern 7.

  The conductor pattern 7 extends in the plane direction orthogonal to the thickness direction of the resin layer 2 and is disposed on the main surface of the resin layer 2. Via conductors 6 penetrating the resin layer 2 in the thickness direction electrically connect the conductor patterns 7 formed at different interfaces between the resin layers 2. A conductive wiring pattern is formed inside. As shown in FIG. 1, two via conductors 6 connected in series, and a conductor pattern 7 arranged so as to be in contact with both main surfaces 2a of the resin layer 2 through which the two via conductors 6 pass, Constitutes the hard member 8 incorporated in the resin multilayer substrate 101. The hard member 8 has a relatively greater hardness than the material for forming the resin layer 2.

  A part of the plurality of via conductors 6 constitutes a via conductor 6a. The via conductor 6a is disposed in the vicinity of the outer edge 8d of the hard member 8 when viewed in the stacking direction of the plurality of resin layers 2 (vertical direction in FIG. 1). A part of the plurality of conductor patterns 7 constitutes a conductor pattern 7a formed on the main surface 2a of the resin layer 2 on which the via conductor 6a is formed. The conductor pattern 7 a is arranged extending in the surface direction of the resin layer 2. The conductor pattern 7a is connected to the via conductor 6a. The conductor pattern 7a is disposed on the main surface 2a on both sides of the resin layer 2 through which the via conductor 6a passes.

  The conductor pattern 7 a has an enlarged portion 9 whose area is enlarged on the side away from the hard member 8 when viewed in the laminating direction of the resin layer 2. In the present embodiment, since the conductor pattern 7a is arranged on the main surface 2a on both sides of the resin layer 2 on which the via conductor 6a is formed, the enlarged portion 9 also has the resin layer 2 on which the via conductor 6a is formed. Are formed on the main surface 2a on both sides.

  The via conductor 6a has a truncated cone shape. In the cross section shown in FIG. 2, an annular conductor pattern 7a is provided so as to surround the circumference of the circle showing the cross section of the via conductor 6a. The enlarged portion 9 is provided such that a part of the annular conductor pattern 7a on the side away from the hard member 8 enlarges the outer diameter so that the area of the conductor pattern 7a is enlarged. The enlarged portion 9 is formed in a shape in which a part of the center of a sector shape having an angle of 180 ° is cut out along an arc.

  The enlarged portion 9 is not limited to the shape shown in FIG. 2 and may have various shapes. For example, the shape may be a combination of a polygon and a partial shape of a circle as shown in FIG. 3, or may be a partial shape of a circle as shown in FIG. It may be a partial shape of any polygon. As shown in FIG. 6, the substantially sector shape shown in FIG. 2 may be an enlarged portion 9 having a shape divided in the circumferential direction around the via conductor 6a by a plurality of gap portions 9g. As shown in FIG. 7, a wide arc-shaped conductor is provided on the outer peripheral side of an annular conductor surrounding the via conductor 6a with a gap portion 9g interposed, and the annular shape and the wide arc shape are connected to the via. It is good also as the enlarged part 9 of the shape connected by the some bridge | bridging part 9b extended in the radial direction centering on the conductor 6a.

  As shown in FIG. 8, a plurality of arc-shaped conductors are provided on the outer peripheral side of the annular conductor surrounding the via conductor 6a with gaps 9g interposed therebetween. It is good also as the enlarged part 9 of the shape connected by the some bridge | bridging part 9b extended in the radial direction centering on the via conductor 6a. As shown in FIG. 9, a plurality of rectangular conductors extending in the radial direction around the via conductor 6a are provided on the outer peripheral side of the annular conductor that surrounds the via conductor 6a, and between the rectangular conductors. It is good also as the enlarged part 9 of the shape in which the gap part 9g was provided.

  As shown in FIGS. 10 to 12, the enlarged portion 9 is divided in the radial direction around the via conductor 6a and is electrically disconnected from the annular conductor surrounding the via conductor 6a. It may be a dummy pattern. As shown in FIG. 11, the enlarged portion 9 may be formed by a wide arc-shaped conductor obtained by removing the bridge portion 9b from the shape shown in FIG. As shown in FIG. 10, the enlarged portion 9 may be formed by a conductor having a shape obtained by further dividing the wide arc-shaped conductor shown in FIG. 11 in the radial direction with the via conductor 6a as the center. As shown in FIG. 12, the enlarged portion 9 may be formed by a plurality of arc-shaped conductors obtained by removing the bridge portion 9b from the shape shown in FIG.

  As shown in FIGS. 13 and 14, the connection conductor 10 may be connected to the conductor pattern 7a. As shown in FIG. 13, with respect to the conductor pattern 7a having the shape shown in FIG. 7, the connection conductor 10 is connected to an annular conductor surrounding the via conductor 6a, and the via conductor 6a is connected to the annular conductor and It is good also as a structure electrically connected with the external member which is not shown in figure via the connection conductor 10. FIG. As shown in FIG. 14, the connection conductor 10 is connected to a conductor having a wide arc shape with respect to the conductor pattern 7a having the shape shown in FIG. 7, and the via conductor 6a includes the ring-shaped conductor, the bridge portion 9b, the wide arc. It is good also as a structure electrically connected with the external member which is not shown in figure through the shape conductor and the connection conductor 10.

  Note that the enlarged portion 9 does not have to have the same shape in all layers, and those having different shapes may be used in combination. For example, the enlarged portions 9 shown in FIGS. 6 to 14 can be used in appropriate combination.

  Next, the relative positional relationship between the via conductor 6a and the hard member 8 will be described with reference to FIGS. In FIGS. 15 and 16, the hard member 8 having the wiring pattern shown in FIG. 1 is schematically shown as a rectangle. The alternate long and two short dashes line shown in FIGS. 15 and 16 indicates a straight line that extends in the laminating direction of the resin layer 2 through the outer edge 8 d of the hard member 8.

  As shown in FIG. 15, the via conductor 6 a of the present embodiment may be arranged at a position overlapping the outer edge 8 d of the hard member 8 when viewed in the laminating direction of the resin layer 2. Alternatively, as shown in FIG. 16, the via conductor 6 a does not overlap with the hard member 8 when viewed in the laminating direction of the resin layer 2, and is separated from the outer edge 8 d of the hard member 8 by a predetermined distance. It may be arranged. The length L shown in FIG. 6 indicates the distance from the outer edge 8d of the hard member 8 to the center line of the via conductor 6a in the surface direction of the resin layer 2 (or the surface direction of the resin multilayer substrate 101). The via conductor 6a may be arranged at a position where the length L is 300 μm or less. In other words, “the vicinity of the outer edge 8d of the hard member 8” where the via conductor 6a of the present embodiment is to be disposed is whether the via conductor 6a overlaps the outer edge 8d of the hard member 8 when viewed in the laminating direction of the resin layer 2 Alternatively, it is defined as a range in which the distance at which the center of the via conductor 6a at a position not overlapping the hard member 8 when viewed in the laminating direction of the resin layer 2 is separated from the outer edge 8d of the hard member 8 is 300 μm or less.

(Action / Effect)
In the present embodiment, the via conductor 6a is disposed in the vicinity of the outer edge 8d of the hard member 8 built in the resin multilayer substrate 101 when viewed in the stacking direction of the plurality of resin layers 2, and is connected to the via conductor 6a. The conductive pattern 7 a has an enlarged portion 9 whose area is enlarged on the side away from the hard member 8 when viewed in the laminating direction of the resin layer 2.

  When the resin multilayer substrate 101 is pressed from above and below in the thickness direction during thermocompression bonding of the resin multilayer substrate 101, the resin layer 2 made of a plurality of thermoplastic resin materials softens and flows, and the via conductor 6a tilts or moves. Sometimes. For this reason, there is a concern that the jointability of the joint portion between the via conductor 6a and the conductor pattern 7a is deteriorated or short-circuited with another conductor. In particular, since the hard member 8 is not deformed or hardly deformed even during thermocompression bonding, the via conductor 6a disposed in the vicinity of the outer edge 8d of the hard member 8 is likely to be inclined and moved unintentionally.

  In addition, after the product is manufactured as the resin multilayer substrate 101, the resin multilayer substrate 101 may be bent and used, or an unintended bend may occur, and bending stress may be applied to the resin multilayer substrate 101. In particular, since the hard member 8 is not deformed or hardly deformed even when bent, the via conductor 6a disposed in the vicinity of the outer edge 8d of the hard member 8 is likely to generate an unintended inclination or movement. Therefore, there is the greatest concern about the jointability of the joint portion between the via conductor 6a and the conductor pattern 7a disposed in the vicinity of the outer edge 8d of the hard member 8.

  In particular, the via conductor 6a is likely to be inclined or moved toward the side away from the hard member 8, and stress is likely to be generated, so that the via conductor 6a is separated from the hard member 8. If the enlarged portion 9 according to the present embodiment is provided on the side, the via conductor 6a can be made difficult to be deformed, so that it is possible to prevent the peeling of the joint between the via conductor 6a and the conductor pattern 7a. Therefore, it is possible to improve the reliability of bonding between the via conductor 6a and the conductor pattern 7a.

  Due to the improved bondability between the via conductor 6a and the conductor pattern 7a, even when the via conductor 6a is disposed in the vicinity of the outer edge 8d of the hard member 8, the bond between the via conductor 6a and the conductor pattern 7a is peeled off. Can be suppressed. Therefore, it is allowed to arrange the via conductor 6a near the outer edge 8d of the hard member 8, and the via conductor 6a can be freely arranged regardless of the arrangement of the hard member 8. Therefore, the freedom degree of arrangement | positioning of the via conductor 6a can be improved.

  As shown in FIG. 8 or FIG. 12, the enlarged portion 9 has a structure that extends concentrically around the via conductor 6a, thereby improving the bondability between the via conductor 6a and the conductor pattern 7a, and the resin multilayer substrate 101. Flexibility can be improved, and it is possible to ensure the ease of bending when a bending stress is applied to the resin multilayer substrate 101. As shown in FIG. 6 or FIG. 10, the enlarged portion 9 is divided in the circumferential direction around the via conductor 6a, and the enlarged portion 9 is formed by a conductor that radiates from the joint portion between the via conductor 6a and the conductor pattern 7a. Further, even when a part of the radially extending conductor is deformed, it is possible to suppress the deformation from being transmitted to other conductors, and thus it is possible to further strengthen the bending.

  As shown in FIGS. 10 to 12, if the enlarged portion 9 is divided in the radial direction centered on the via conductor 6 a and the enlarged portion 9 has a portion that is not electrically connected to other conductors. The portion can be provided as a dummy pattern. By providing the enlarged portion 9 as a dummy pattern, it is possible to avoid the generation of unnecessary capacitance, and therefore it is possible to suppress the deviation in characteristics and the occurrence of defects of the resin multilayer substrate 101.

  As shown in FIG. 1, by forming the enlarged portions 9 on the main surface 2a on both sides of the resin layer 2 on which the via conductor 6a is formed, the via conductor 6a becomes more difficult to deform, and the via conductor 6a and the conductor pattern Separation of the joint with 7a can be more reliably prevented. Therefore, the reliability of joining between the via conductor 6a and the conductor pattern 7a can be further improved.

(Production method)
With reference to FIGS. 17-22, the manufacturing method of the resin multilayer substrate 101 in this Embodiment is demonstrated.

  First, a resin sheet 12 with a conductive foil as shown in FIG. 17 is prepared. The resin sheet with conductor foil 12 is a sheet having a structure in which the conductor foil 17 is attached to one surface of the resin layer 21. The resin layer 21 is made of a thermoplastic resin. The thermoplastic resin may be, for example, LCP (liquid crystal polymer), PEEK (polyether ether ketone), PEI (polyether imide), PPS (poniphenylene sulfide), thermoplastic PI (polyimide), and the like. The material of the conductor foil 17 may be Cu, Ag, Al, SUS, Ni, Au, or may be an alloy of two or more different metals selected from these metals.

  The thickness of the resin layer 21 may be a thickness of about 10 μm or more and 100 μm or less. For example, the thickness of the resin layer 21 may be 25 μm or 50 μm. The thickness of the conductor foil 17 may be any thickness that allows circuit formation of about 5 μm to 35 μm. For example, the conductor foil 17 may be a foil having a thickness of 12 μm or a thickness of 18 μm. For example, the ratio between the thickness of the conductor foil 17 and the thickness of the resin layer 21 may be in the range of 1: 2 to 1: 5. The surface of the conductive foil 17 is formed so that the surface roughness Rz is 3 μm, for example.

  After preparing a plurality of strip-shaped resin sheets 12 with conductor foil, the following conductor pattern forming operation may proceed. However, as another method, Next, prepare a plurality of resin sheets with strip-shaped areas that should be cut out individually, proceed with the formation work of the following conductor patterns etc. in large size, and then cut into strips Also good. Here, the description will be continued assuming that the strip-shaped resin sheet 12 with conductive foil has already been cut out.

  Next, as shown in FIG. 18, the resin layer 21 is penetrated by irradiating the surface on the side of the resin layer 21 opposite to the surface to which the conductor foil 17 of the resin sheet 12 with the conductor foil adheres with a carbon dioxide laser beam. The via hole 11 is formed as described above. The via hole 11 penetrates the resin layer 21 but does not penetrate the conductor foil 17. Thereafter, the smear in the via hole 11 is removed by chemical treatment such as permanganic acid as necessary. In order to form the via hole 11, a laser beam of a different type from the carbon dioxide laser beam may be used. However, it is preferable to use laser light that penetrates the resin layer 21 but does not penetrate the conductor foil 17. Further, in order to form the via hole 11, a method other than laser beam irradiation, such as punching, may be employed.

  Next, as shown in FIG. 19, a resist pattern 13 is printed on the surface of the conductor foil 17 of the resin sheet 12 with a conductor foil by a method such as screen printing. The resist pattern 13 is printed at a position overlapping the via hole 11 when viewed in the thickness direction of the resin sheet 12 with conductor foil. The resist pattern 13 overlapping the via hole 11 corresponds to the conductor pattern 7a connected to the via conductor 6a.

  Next, etching is performed using the resist pattern 13 as a mask, and the portion of the conductor foil 17 that is not covered with the resist pattern 13 is removed as shown in FIG. A portion of the conductor foil 17 remaining after the etching becomes a conductor pattern 7 a including the enlarged portion 9. Thereafter, the resist pattern 13 is removed using a cleaning liquid or the like.

  In this way, the via hole 11 penetrating the resin layer 21 in the thickness direction is formed, and the desired conductor pattern 7 is formed on one surface of the resin layer 21, so that the perforated resin sheet shown in FIG. Is obtained. The order of forming the via hole 11 and the conductor pattern 7a is not limited to the order described above, and may be the order in which the via hole 11 is formed after the conductor pattern 7 is formed.

  Next, the via hole 11 formed in the resin layer 21 is filled with a conductive paste by screen printing or the like. Screen printing is performed from the surface on the side where the conductor pattern 7a is not arranged, that is, the lower surface in FIG. Actually, when performing screen printing, the orientation of the perforated resin sheet may be appropriately changed. The conductive paste to be filled may contain an appropriate amount of metal powder that forms an alloy layer with the metal that is the material of the conductor pattern 7a at the temperature when the laminated resin layer 21 is thermocompression bonded later. preferable. This conductive paste preferably contains at least one of Ag, Cu, and Ni and at least one of Sn, Bi, and Zn.

  By filling the conductive paste in this way, the configuration shown in FIG. 22 is obtained in which the via conductor 6a is inserted into the through hole of the perforated resin sheet and the via conductor 6a penetrating the resin layer 21 in the thickness direction is formed.

  Up to this point, the processing in one resin layer 21 has been described as an example. However, in the other resin layers 21 as well, the same processing is performed to appropriately form a conductor pattern 7 in a desired region, and vias are provided as necessary. A conductor 6 is formed.

  Next, a plurality of resin layers 21 including the perforated resin sheet and other resin sheets shown in FIG. 22 are laminated to form a laminate. Subsequently, pressure and heat are applied to the laminate of the plurality of resin layers 21. In this way, the plurality of resin layers 21 included in the multilayer body are thermocompression bonded to each other, and the conductive paste of the via conductor 6a is metallized. As a result, the resin multilayer substrate 101 shown in FIG. 1 is formed. You may heat and pressurize by putting a release material on the upper and lower surfaces of a laminated body, and also inserting | pinching with the press board from the upper and lower sides. By using the release material, the work of taking out the resin multilayer substrate 101 obtained after thermocompression bonding from between the press plates can be performed smoothly.

  By carrying out the manufacturing method in this way, the via conductor 6a is arranged in the vicinity of the outer edge 8d of the hard member 8, and the conductor pattern 7a has the enlarged portion 9 on the side away from the outer edge 8d of the hard member 8. Accordingly, it is possible to easily obtain the resin multilayer substrate 101 in which the reliability of the joint portion between the via conductor 6a and the conductor pattern 7a is improved. Since the enlarged portion 9 can be formed simultaneously with the formation of the conductor pattern 7a that functions as a land for receiving the via conductor 6a, an additional process for forming the enlarged portion 9 is not necessary. Therefore, the enlarged portion 9 can be formed without an increase in manufacturing cost.

(Embodiment 2)
With reference to FIG. 23, FIG. 24 and FIG. 25, resin multilayer substrate 101 according to the second embodiment of the present invention will be described. The resin multilayer substrate 101 of the second embodiment has substantially the same configuration as that of the first embodiment, and differs from the first embodiment in that it further includes a small-diameter via conductor 6b in addition to the via conductor 6a. ing.

  The small-diameter via conductor 6b has a smaller outer dimension than the via conductor 6a. When the via conductor 6a has a truncated cone shape, the small diameter via conductor 6b may have a truncated cone shape in which the diameters of the bottom surface and the upper surface are relatively smaller than the via conductor 6a. The small diameter via conductor 6 b penetrates the resin layer 2 in which the via conductor 6 a is formed in the thickness direction, and is connected to the enlarged portion 9.

  As shown in FIG. 24, a single small-diameter via conductor 6b may be provided on the side away from the hard member 8 with respect to the via conductor 6a. Alternatively, as shown in FIG. 25, in addition to the small-diameter via conductor 6b provided on the side away from the hard member 8 with respect to the via conductor 6a, the small-diameter via conductor 6b is also provided on a concentric circle centering on the via conductor 6a. It is good also as a structure provided with the some small diameter via conductor 6b.

  In the present embodiment, since the via conductor 6a is provided with the small-diameter via conductor 6b, it is possible to make the via conductor 6a more difficult to deform, so that the bonding strength between the via conductor 6a and the conductor pattern 7a can be further improved. Therefore, since peeling of the joint between the via conductor 6a and the conductor pattern 7a when bending stress is applied to the resin multilayer substrate 101 can be prevented more reliably, the reliability of the joining between the via conductor 6a and the conductor pattern 7a is further increased. Can be improved.

  A small-diameter via conductor 6b made of a conductive material is provided around the via conductor 6a. By increasing the metal density around the via conductor 6a, heat transfer from the via conductor 6a to the small-diameter via conductor 6b can be promoted. The heat dissipation of the wiring pattern can be improved by the heat dissipation via the small diameter via conductor 6b.

(Embodiment 3)
With reference to FIG. 26, resin multilayer substrate 101 according to the third embodiment of the present invention will be described. In the resin multilayer substrate 101 of the first and second embodiments, the edge of the enlarged portion 9 formed on the main surface 2a on both sides of the resin layer 2 on which the via conductor 6a is formed, on the side away from the hard member 8, The resin layers 2 overlap each other when viewed in the stacking direction. That is, in the resin multilayer substrate 101 of the first and second embodiments, the edge portion on the side away from the hard member 8 of the enlarged portion 9 arranged on one main surface 2a of the resin layer 2 on which the via conductor 6a is formed, The enlarged portion 9 disposed on the other main surface 2 a of the resin layer 2 has a portion that coincides with the edge portion on the side away from the hard member 8. On the other hand, in the third embodiment, the edge portion on the side away from the hard member 8 of the enlarged portion 9 formed on the main surface 2a on both sides of the resin layer 2 on which the via conductor 6a is formed is the resin layer 2. They are not overlapped when viewed in the stacking direction, but are shifted from each other.

  Even in such a configuration, since the resin multilayer substrate 101 includes the conductor pattern 7a having the enlarged portion 9, the via conductor 6a is not easily deformed, and the via conductor 6a and the conductor pattern 7a are not deformed. Can be prevented from peeling off. Therefore, as in the second embodiment, the reliability of bonding between the via conductor 6a and the conductor pattern 7a can be improved.

(Embodiment 4)
With reference to FIG. 27, the resin multilayer substrate 101 in Embodiment 4 based on this invention is demonstrated. In the first to third embodiments so far, the example in which the wiring pattern provided inside the resin multilayer substrate 101 functions as a hard member having a hardness higher than that of the material for forming the peripheral resin layer 2 has been described. In the fourth embodiment, as shown in FIG. 27, a component 31 is built in the resin multilayer substrate 101, and the component has a function as the hard member 8.

  A component 31 shown in FIG. 27 is disposed through the two resin layers 2 in the thickness direction. A plurality of wiring patterns including via conductors 6 and conductor patterns 7 are connected to the component 31. Via conductors 6a are arranged in the vicinity of the outer edges 8d on both sides of the component 31, and a conductor pattern 7a similar to that of the second embodiment is connected to the via conductor 6a and is away from the component 31 with respect to the via conductor 6a. A small diameter via conductor 6b is provided on the side. Inside the resin multilayer substrate 101, another conductor pattern 7 and a wiring pattern composed of the other via conductor 6 and conductor pattern 7 are further provided.

  The component 31 may be a passive component such as a multilayer ceramic capacitor or a chip inductor, an electronic component such as an integrated circuit or a semiconductor element, or a hard substrate such as a ferrite core used for antenna use.

  Even in such a configuration, since the resin multilayer substrate 101 includes the conductor pattern 7a having the enlarged portion 9, the via conductor 6a is not easily deformed, and the via conductor 6a and the conductor pattern 7a are not deformed. Can be prevented from peeling off. Therefore, as in the first embodiment, the reliability of bonding between the via conductor 6a and the conductor pattern 7a can be improved.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Laminated body, 2,21 Resin layer, 2a Main surface, 1st main surface, 4 2nd main surface, 6,6a Via conductor, 6b Small diameter via conductor, 7, 7a Conductor pattern, 8 Hard member, 8d Outer edge, DESCRIPTION OF SYMBOLS 9 Enlarged part, 9b Bridge part, 9g Gap part, 10 Connection conductor, 11 Via hole, 12 Resin sheet with conductor foil, 13 Resist pattern, 17 Conductor foil, 31 Parts, 101 Resin multilayer board.

Claims (6)

A resin multilayer substrate having a main surface and formed by laminating a plurality of resin layers made of thermoplastic resin,
A via conductor that penetrates one of the resin layers in the thickness direction; and
A conductor pattern formed on the main surface of the resin layer in which the via conductor is formed and connected to the via conductor;
Embedded in the resin multilayer substrate, comprising a hard member having a relatively greater hardness than the resin layer,
The via conductor is disposed in the vicinity of the outer edge of the hard member when viewed in the stacking direction of the plurality of resin layers,
The said conductor pattern is a resin multilayer substrate which has an enlarged part which the area expanded on the side away from the said hard member seeing in the said lamination direction.   The resin multilayer substrate according to claim 1, wherein the enlarged portion is divided in a circumferential direction around the via conductor.   The resin multilayer substrate according to claim 1, wherein the enlarged portion is divided in a radial direction centering on the via conductor.   The resin multilayer substrate according to claim 3, wherein the enlarged portion divided in the radial direction includes a dummy pattern that is electrically disconnected from other conductors.   The resin multilayer substrate according to claim 1, wherein the enlarged portion is formed on the main surface on both sides of the resin layer on which the via conductor is formed. Further comprising a small diameter via conductor having a smaller outer dimension than the via conductor;
6. The resin multilayer substrate according to claim 1, wherein the small-diameter via conductor penetrates the resin layer in which the via conductor is formed in a thickness direction and is connected to the enlarged portion. .

Images