JP2007027368A - Multilayer interconnection board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability in electronic components by preventing solder-up failure from occurring. <P>SOLUTION: A multilayer interconnection board comprises a plurality of base materials, a plurality of conductive layers that are laminated to each base material for formation and have a prescribed wiring pattern, and a land 16 arranged at a through hole 15 penetrating the base materials and the conductive layers. The leads of electronic components are inserted into the through hole 15, the leads and the land 16 are connected by a jointing material, and a component surface Sa and a solder surface Sb are formed on one surface and the other, respectively. Then, a wiring pattern having a large heat capacity in the wiring patterns is connected to the land 16 at the side of the solder surface Sb by a wiring pattern having a small heat capacity. When soldering electronic components to the multilayer interconnection board 11, much amount of heat in solder cannot be transmitted to the wiring pattern having a large heat capacity. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multilayer wiring board.

  Conventionally, a substrate having a multilayer wiring structure formed by laminating a plurality of base materials and conductive layers, that is, when various electronic components are attached to and electrically connected to a multilayer wiring substrate, for example, a point flow (Spot flow) type soldering is performed.

  For this purpose, the multilayer wiring board has a component surface formed on one surface and a solder surface formed on the other surface, and a through hole is formed between the component surface and the solder surface. Electronic component leads are inserted. A land is disposed in the through hole in order to electrically connect a predetermined arrangement pattern of the arrangement patterns of each conductive layer and the lead.

  In the point flow type soldering, a soldering area is set over a predetermined area including each point to be soldered on the solder surface (hereinafter referred to as “soldering point”), and each solder in the soldering area is set. The melted solder is simultaneously supplied to the attachment point.

  For this purpose, a nozzle having an area sufficient to enclose the entire soldering area is advanced by the solder robot, placed in a position almost in contact with the soldering area, that is, the soldering position, and melted in the nozzle. The solder is discharged and applied toward each soldering point.

  In the solder surface, the solder discharged from the leading end side of the lead toward the through hole has a gap (clearance) between the inner peripheral surface of the through hole and the outer peripheral surface of the lead from the solder surface side. Flows toward the component surface and exits from the through hole from the component surface. As a result, the solder fills the through hole, and a conical solder fillet is formed on the solder surface and the component surface.

  However, in the conventional point flow type soldering, the heat capacity of the solder may be smaller than that of the normal flow type soldering, so that heat may be lost to the conductive layer. For example, when attaching a connector as an electronic component to a multilayer wiring board, the lead of the connector and the arrangement pattern are connected in a through hole. When the heat capacity of the predetermined arrangement pattern is large, When a large amount of heat of the solder is transmitted to the arrangement pattern, it is not possible to sufficiently supply the melted solder from the solder surface side to the component surface side, and a solder rise failure is likely to occur.

  When this kind of soldering failure occurs, disconnection may occur due to vibrations and the like, so soldering is corrected manually. However, when correcting the soldering manually, it is necessary to perform it at a higher temperature (usually 300 [° C.] or higher) than the flow type soldering. The reliability of electronic components may be reduced.

  The present invention provides a multilayer wiring board capable of solving the problems of the conventional multilayer wiring board, preventing the occurrence of defective soldering, and improving the reliability of electronic components. With the goal.

  Therefore, in the multilayer wiring board of the present invention, a plurality of base materials, a plurality of conductive layers formed by being laminated on the respective base materials and having a predetermined wiring pattern, and penetrating the base material and the conductive layers And a land of the electronic component is inserted into the through hole, the lead and the land are connected by a bonding material, and the electronic component is attached to one surface. The component surface is formed with a solder surface for soldering to the other surface.

  A wiring pattern having a large heat capacity among the wiring patterns is connected to the land on the solder surface side of the wiring pattern having a small heat capacity.

  In another multilayer wiring board of the present invention, the wiring pattern having a larger area among the wiring patterns is connected to the land on the solder surface side than the wiring pattern having a smaller area.

  In still another multilayer wiring board of the present invention, a thick conductive layer among the conductive layers is further disposed on the solder surface side than the thin conductive layer.

  In yet another multilayer wiring board of the present invention, a plurality of base materials, a plurality of conductive layers formed on each base material and having a predetermined wiring pattern, and penetrating the base material and the conductive layers And a land of the electronic component is inserted into the through hole, the lead and the land are connected by a bonding material, and the electronic component is attached to one surface. The component surface is formed with a solder surface for soldering to the other surface.

  A wiring pattern having a high thermal conductivity among the wiring patterns is connected to the land on the solder surface side of the wiring pattern having a low thermal conductivity.

  In still another multilayer wiring board of the present invention, the thermal conductivity of the wiring pattern is further adjusted by changing the material constituting the conductive layer.

  In still another multilayer wiring board of the present invention, the wiring pattern connected to the land on the solder surface side is formed as a solid pattern.

  In still another multilayer wiring board of the present invention, the wiring pattern connected to the land on the solder surface side is formed by a thick wiring for supplying power.

  In still another multilayer wiring board of the present invention, a groove for reducing the amount of heat transmitted from the land to the wiring pattern is formed between the land and the wiring pattern.

  According to the present invention, in a multilayer wiring board, a plurality of base materials, a plurality of conductive layers formed by being laminated on the respective base materials and having a predetermined wiring pattern, and penetrating the base material and the conductive layers And a land of the electronic component is inserted into the through hole, the lead and the land are connected by a bonding material, and the electronic component is attached to one surface. The component surface is formed with a solder surface for soldering to the other surface.

  A wiring pattern having a large heat capacity among the wiring patterns is connected to the land on the solder surface side of the wiring pattern having a small heat capacity.

  In this case, the wiring pattern having a large heat capacity among the wiring patterns is connected to the land on the solder surface side of the wiring pattern having a small heat capacity. Therefore, when the electronic component is soldered to the multilayer wiring board, the amount of heat of the solder is reduced. Many are not transferred to the arrangement pattern with a large heat capacity. Therefore, it is possible to sufficiently supply the melted solder from the solder surface side toward the component surface side, and it is possible to prevent occurrence of defective soldering.

  As a result, disconnection does not occur due to vibration or the like, so there is no need to manually correct the soldering. Further, even if it is necessary to correct the soldering manually, it is not necessary to perform the correction work for a long time, so that the reliability of the electronic component can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a main part of a multilayer wiring board according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing an attachment state of a connector in the embodiment of the present invention, and FIG. FIG. 4 is a first diagram showing the relationship between the land portion and the arrangement pattern of the first conductive layer, and FIG. 4 is a first diagram showing the relationship between the land portion and the arrangement pattern of the second conductive layer in the embodiment of the present invention. FIG. 1 is a first view showing the relationship between the land portion and the arrangement pattern of the third conductive layer in the embodiment of the present invention, and FIG. 6 is a view showing the relationship between the land portion and the third conductive layer in the embodiment of the present invention. It is a 1st figure which shows the relationship with the arrangement | positioning pattern of 4 conductive layers.

  In the figure, reference numeral 11 denotes a multilayer wiring board. A component surface Sa such as a connector 21 is formed on one surface of the multilayer wiring substrate 11, and a solder surface Sb for soldering is formed on the other surface. In the present embodiment, the multilayer wiring board 11 includes a plurality of first to third base materials Bi (i = 1 to 3) as the base material, and the first to third base materials. The first to fourth conductive layers εj (j = 1 to 4) formed by laminating on both sides of Bi with a predetermined thickness, and the first and fourth conductive layers ε1 and ε4, not shown With layers.

  Each of the first to third base materials Bi is made of a highly insulating material (hereinafter referred to as “insulator”) such as resin, ceramics, paper phenol, etc., and in this embodiment, glass epoxy resin has a predetermined thickness. The first to fourth conductive layers εj are formed by plating with a highly conductive material such as copper or tungsten (hereinafter referred to as “conductor”) and have a predetermined wiring pattern. The covering layer is formed of an insulator, in the present embodiment, a solder resist.

  In addition to the connector 21, electronic components such as an integrated circuit chip, a semiconductor package, a chip transistor, a chip diode, a chip resistor, a chip capacitor, and a chip coil are attached to the component surface Sa. A predetermined electronic component is also attached to the solder surface Sb.

  The through hole 15 is formed so as to penetrate from the component surface Sa toward the solder surface Sb, and a plurality of leads tuk (k = 1, 2,...), Tdm (m = 1, 2, ...) is inserted.

  Further, in order to electrically connect the leads tuk, tdm and a predetermined arrangement pattern among the arrangement patterns of the first to fourth conductive layers εj, A cylindrical land 16 is disposed. The land 16 is formed by plating with a highly conductive material such as copper or tungsten, and extends from the component surface Sa toward the solder surface Sb, and both surfaces of the first to third base materials Bi. The first to fourth conductive layers εj corresponding to each of the first and fourth conductive layers εj and projecting from the cylindrical portion 17 outward in the radial direction. A fourth land portion Lj (j = 1 to 4) is provided, and a predetermined land portion of each of the first to fourth land portions Lj is electrically connected to a corresponding arrangement pattern.

  Then, when the molten solder as the bonding material is discharged from the tip side of the leads tuk and tdm toward the through hole 15 on the solder surface Sb, the solder is connected to the inner peripheral surface of the through hole 15 and the lead tuk. , Tdm, and the outer peripheral surface, flows from the solder surface Sb side toward the component surface Sa side, and comes out of the through hole 15 from the component surface Sa side. As a result, the solder fills the through hole 15, and conical solder fillets f1 and f2 are formed on the solder surface Sb and the component surface Sa.

  By the way, in the point flow type soldering, the heat capacity of the solder is smaller than that in the normal flow type soldering, so that heat is taken away by the arrangement pattern of the first to fourth conductive layers εj. Sometimes. That is, when the heat capacity of a predetermined arrangement pattern among the arrangement patterns of the first to fourth conductive layers εj is large, when a large amount of heat of solder is transmitted to the arrangement pattern, the solder surface Sb side Therefore, it becomes impossible to sufficiently supply the solder melted from the side toward the component surface Sa, and a solder rise failure is likely to occur.

  Therefore, in the present embodiment, an arrangement pattern having a larger area and a larger heat capacity is arranged on the solder surface Sb side, and an arrangement pattern having a smaller area and a smaller heat capacity is arranged on the component surface Sa side. That is, of the arrangement patterns, the arrangement pattern having a large heat capacity is connected to the land 16 on the solder surface Sb side than the arrangement pattern having a small heat capacity. In addition, the arrangement pattern having a smaller heat capacity is connected to the land 16 on the component surface Sa side than the arrangement pattern having a larger heat capacity. The arrangement pattern and the land 16 can be prevented from being connected on the component surface Sa side.

  For example, when attaching the connector 21 to the multilayer wiring board 11, when the ground lead of the leads tuk and tdm is td1, the conductive layer of one of the second to fourth conductive layers ε2 to ε4 As the arrangement pattern, the arrangement pattern of the third conductive layer ε3 or the fourth conductive layer ε4 is preferably used for grounding, and the wiring pattern is formed as a solid pattern. In the present embodiment, the arrangement pattern of the third conductive layer ε3 is used for grounding, and the lead td1 and the arrangement pattern of the third conductive layer ε3 are connected.

  In this case, since the arrangement pattern of the third conductive layer ε3 is formed as a solid pattern, it has a large heat capacity, but is formed at a position close to the solder surface Sb. It is not transmitted to the arrangement pattern of the layer ε3. Therefore, it is possible to sufficiently supply the melted solder from the solder surface Sb side to the component surface Sa side, and it is possible to prevent the occurrence of defective soldering.

  In addition, when the third land portion L3 is an inner land portion and the arrangement pattern of the third conductive layer ε3 is an outer land portion, the inner land portion and the outer land portion have a plurality of locations in the circumferential direction. In the embodiment, they are connected via the bridging portions cn1 to cn4 formed at four locations.

  A fan-shaped groove d1 is formed between the bridging portions cn1 and cn2, a fan-shaped groove d2 is formed between the bridging portions cn2 and cn3, a fan-shaped groove d3 is formed between the bridging portions cn3 and cn4, and a fan-shaped groove d3 is formed between the bridging portions cn4 and cn1. A groove d4 is formed, and a thermal land is configured by the third land portion L3, the arrangement pattern of the third conductive layer ε3, the bridging portions cn1 to cn4, and the grooves d1 to d4.

  The thermal land is used to reduce the amount of heat transferred from the land to the solid pattern by connecting the land and the solid pattern and thermally separating the land and the solid land pattern. The greater the clearance, that is, the larger the radial length of the grooves d1 to d4, the less the amount of heat that moves from the land to the solid pattern, and the smaller the radial length of the grooves d1 to d4, the smaller the distance to the solid pattern that moves. The amount of heat increases. In the present embodiment, the lengths in the radial direction of the grooves d1 to d4 are 0.5 [mm] or more.

  Therefore, since it is possible to further suppress the amount of heat of the solder from being transferred to the arrangement pattern of the third conductive layer ε3, the solder melted from the solder surface Sb side toward the component surface Sa side can be more sufficiently obtained. Therefore, it is possible to further prevent the occurrence of defective soldering.

  By the way, it is preferable that a conductive layer having a wiring pattern formed of a thick wiring (for example, a pattern width of 1 [mm] or more) other than the solid pattern is also formed on the solder surface Sb side. Next, the multilayer wiring substrate 11 in which a wiring pattern formed of thick wiring is formed on the solder surface Sb side will be described.

  FIG. 7 is a second view showing the relationship between the land portion and the arrangement pattern of the first conductive layer in the embodiment of the present invention, and FIG. 8 is the land portion and the second conductive layer in the embodiment of the present invention. FIG. 9 is a second view showing the relationship between the land portion and the third conductive layer placement pattern in the embodiment of the present invention, and FIG. It is a 2nd figure which shows the relationship between the land part and arrangement | positioning pattern of a 4th conductive layer in embodiment of invention.

  In this case, when the connector 21 (FIG. 2) is disposed between a power supply circuit (not shown) and a predetermined circuit formed on the multilayer wiring board 11 and power is supplied through the connector 21, each lead tuk , Tdm, it is necessary to connect a predetermined lead to a wiring pattern formed of a thick wiring for power supply. Then, of each of the first to fourth conductive layers εj, for example, the arrangement pattern of one of the third and fourth conductive layers ε3 and ε4 is formed by a thick wiring, and this embodiment In the embodiment, the arrangement pattern of the fourth conductive layer ε4 is formed by a thick wiring, and the predetermined lead and the arrangement pattern of the fourth conductive layer ε4 are connected.

  In this case, since the arrangement pattern of the fourth conductive layer ε4 is formed of thick wiring, it has a large heat capacity, but is formed at a position close to the solder surface Sb. It is not transmitted to the arrangement pattern of the layer ε4. Therefore, it is possible to sufficiently supply the melted solder from the solder surface Sb side to the component surface Sa side, and it is possible to prevent the occurrence of defective soldering.

  Thus, the arrangement pattern of the third and fourth conductive layers ε3 and ε4 is formed as a conductive layer having a large heat capacity, and the arrangement pattern of the first conductive layer ε1 on the component surface Sa side is the smallest in the heat capacity. The conductive layer is formed as a conductive layer and is not formed as a conductive layer having a large heat capacity. Therefore, when the connector 21 is soldered to the multilayer wiring board 11, the third and fourth conductive materials having a large amount of heat in the solder have a large heat capacity. It is not transmitted to the arrangement pattern of the layers ε3 and ε4. Therefore, it is possible to sufficiently supply the melted solder from the solder surface side Sb toward the component surface Sa side, and it is possible to prevent the occurrence of a soldering failure.

  As a result, disconnection does not occur due to vibration or the like, so there is no need to manually correct the soldering. Further, even if it is necessary to correct the soldering manually, it is not necessary to perform the correction work for a long time, so that the reliability of each electronic component such as the connector 21 can be improved.

  In the present embodiment, the arrangement pattern of the first to fourth conductive layers εj having a large area and having a large heat capacity is smaller in the area and having a smaller heat capacity than the arrangement pattern having a small heat capacity. The thick conductive layer of the first to fourth conductive layers εj is disposed closer to the solder surface Sb than the thin conductive layer, or is connected to the land 16. Among the four conductive layers εj, a conductive layer having a high thermal conductivity can be disposed closer to the solder surface Sb than a conductive layer having a low thermal conductivity.

  The thermal conductivity is adjusted by changing the materials constituting the first to fourth conductive layers εj, and when the conductive layer having the reference thermal conductivity is formed of copper, the thermal conductivity is higher than that of copper. The conductivity of the conductive layer can be increased by adding a material having a higher conductivity, or the conductivity of the conductive layer can be decreased by adding a material having a lower thermal conductivity than copper.

  In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

It is sectional drawing which shows the principal part of the multilayer wiring board in embodiment of this invention. It is sectional drawing which shows the attachment state of the connector in embodiment of this invention. It is a 1st figure which shows the relationship between the land part in the embodiment of this invention, and the arrangement | positioning pattern of a 1st conductive layer. It is a 1st figure which shows the relationship between the land part in the embodiment of this invention, and the arrangement | positioning pattern of a 2nd conductive layer. It is a 1st figure which shows the relationship between the land part and arrangement | positioning pattern of a 3rd conductive layer in embodiment of this invention. It is a 1st figure which shows the relationship between the land part in the embodiment of this invention, and the arrangement | positioning pattern of a 4th conductive layer. It is a 2nd figure which shows the relationship between the land part and arrangement | positioning pattern of a 1st conductive layer in embodiment of this invention. It is a 2nd figure which shows the relationship between the land part and arrangement | positioning pattern of a 2nd conductive layer in embodiment of this invention. It is a 2nd figure which shows the relationship between the land part in the embodiment of this invention, and the arrangement pattern of the 3rd conductive layer. It is a 2nd figure which shows the relationship between the land part in the embodiment of this invention, and the arrangement | positioning pattern of a 4th conductive layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Multilayer wiring board 15 Through hole 16 Land 17 Cylindrical part 21 Connector Bi 1st-3rd base material d1-d4 Groove Lj 1st-4th land part Sa Component surface Sb Solder surface (epsilon) j 1st-4th Conductive layer

Claims (8)

  A plurality of base materials, a plurality of conductive layers formed on each base material and having a predetermined wiring pattern, and lands disposed in through holes penetrating the base materials and the conductive layers. At the same time, the lead of the electronic component is inserted into the through hole, the lead and the land are connected by a bonding material, and the component surface for mounting the electronic component on one surface is soldered to the other surface A multilayer wiring board having a solder surface for forming the wiring pattern, wherein a wiring pattern having a large heat capacity among the wiring patterns is connected to the land on the solder surface side of the wiring pattern having a small heat capacity. .   The multilayer wiring board according to claim 1, wherein a wiring pattern having a large area among the wiring patterns is connected to the land on a solder surface side of a wiring pattern having a small area.   The multilayer wiring board according to claim 1, wherein a thick conductive layer among the conductive layers is disposed closer to a solder surface than a thin conductive layer.   A plurality of base materials, a plurality of conductive layers formed on each base material and having a predetermined wiring pattern, and lands disposed in through holes penetrating the base materials and the conductive layers. At the same time, the lead of the electronic component is inserted into the through hole, the lead and the land are connected by a bonding material, and the component surface for mounting the electronic component on one surface is soldered to the other surface In the multilayer wiring board on which the solder surface for forming is formed, the wiring pattern having high thermal conductivity among the wiring patterns is connected to the land on the solder surface side than the wiring pattern having low thermal conductivity. Multilayer wiring board.   The multilayer wiring board according to claim 4, wherein the thermal conductivity of the wiring pattern is adjusted by changing a material constituting the conductive layer.   The multilayer wiring board according to claim 1, wherein the wiring pattern connected to the land on the solder surface side is formed as a solid pattern.   The multilayer wiring board according to claim 1, wherein the wiring pattern connected to the land on the solder surface side is formed by a thick wiring for supplying power. The multilayer wiring board according to claim 1, wherein a groove is formed between the land and the wiring pattern for reducing the amount of heat transferred from the land to the wiring pattern.

Images