JP2018198249A - Wiring board - Google Patents

Abstract

To provide a wiring board on whose side face an electrode can be relatively easily arranged.SOLUTION: There is provided a wiring board having a first substrate and a second substrate, therein the first substrate includes: a plurality of first insulating layers overlapped in a thickness direction; and a plurality of first wiring parts arranged in the plurality of first insulating layers, and the second substrate includes: at least one second insulating layer; and at least one second wiring part arranged in at least one second insulating layer, and the second substrate is arranged such that at least a part of a side face of the first substrate is covered with a plate substrate, and the first substrate includes a conduction part provided on the side face on which the second substrate is arranged in the first substrate, and the second wiring part includes an electrode part provided on the second substrate, and electrically connected to the conduction part.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a wiring board.

  In a wiring board for mounting an electronic component such as a semiconductor element, the electronic component may be disposed on a side surface of the wiring board. For example, Patent Document 1 discloses a wiring board in which an electrode for connecting an electronic component is provided on an insulating layer deposited from the top surface to the side surface of the substrate.

JP 2011-199239 A

  Depending on the shape of the electronic component and its application, it is necessary to connect the electrode for connecting the electronic component arranged on the side surface and the wiring portion of the wiring board through the wiring pattern. However, there is a limit to the accuracy of the wiring pattern that can be formed by printing on the side surface of the wiring substrate, and the degree of freedom in design is limited.

  An object of one aspect of the present disclosure is to provide a wiring board in which electrodes can be disposed on a side surface relatively easily.

  One embodiment of the present disclosure is a wiring board including a first substrate and a second substrate. The first substrate has a plurality of first insulating layers stacked in the thickness direction and a plurality of first wiring portions arranged in the plurality of first insulating layers. The second substrate has at least one second insulating layer and at least one second wiring portion disposed on the at least one second insulating layer. Further, the second substrate is disposed so as to cover at least a part of the side surface of the first substrate with the plate surface. The first substrate has a conduction portion provided on a side surface of the first substrate on which the second substrate is disposed. The second wiring part includes an electrode part provided on the second substrate and electrically connected to the conduction part.

  According to such a configuration, the first substrate of the first substrate is covered by covering the side surface of the first substrate with the second substrate on which the second wiring portion including the electrode portion to which the electronic component or the like is connected is formed. The electrode portion can be disposed on the side surface of the wiring board while being electrically connected to the wiring portion. In addition, the degree of freedom in designing the second wiring part, and hence the electrode part, can be increased as compared with the case where the wiring pattern is directly formed on the side surface of the wiring board.

  In one aspect of the present disclosure, the conductive portion may be a via conductor that penetrates the first insulating layer in the thickness direction. According to such a configuration, the conduction portion can be easily formed, and the conduction area with the second conduction portion can be secured to increase the reliability of electrical connection.

  In one aspect of the present disclosure, the second substrate may include a plurality of second insulating layers stacked in the thickness direction and a plurality of second wiring portions arranged in the plurality of second insulating layers. According to such a configuration, since a more complicated wiring pattern can be formed on the second substrate, the degree of freedom in designing the electrode portion can be further increased.

  In one aspect of the present disclosure, the second substrate may be arranged to cover at least a part of the plate surface of the first substrate in addition to at least a part of the side surface of the first substrate. According to such a configuration, since the area of the second substrate is increased, the degree of freedom in designing the wiring pattern on the second substrate is further increased. As a result, impedance adjustment and the like are facilitated.

It is a typical perspective view of the wiring board of an embodiment. It is typical sectional drawing in the II-II line | wire of FIG. It is a flowchart which shows the manufacturing method of the wiring board of FIG. It is typical sectional drawing which shows the manufacturing process of the wiring board of FIG. It is typical sectional drawing of the wiring board of embodiment different from FIG. It is typical sectional drawing of the wiring board of embodiment different from FIG.1 and FIG.5. It is typical sectional drawing which shows the manufacturing process of the wiring board of FIG.

Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings.
[1. First Embodiment]
[1-1. Wiring board]
A wiring substrate 1 shown in FIGS. 1 and 2 includes a first substrate 2 and a second substrate 3.

  The wiring board 1 is configured to be able to mount electronic components. Electronic components mounted on the wiring board 1 include semiconductor elements, crystal oscillators, crystal oscillators, piezoelectric oscillators, surface acoustic wave filters and other elements, various sensors, micro electromechanical systems (MEMS), and integrated circuits (ICs). Etc.

<First substrate>
The first substrate 2 is a sheet-like member having two opposing plate surfaces and a side surface parallel to the thickness direction. The first substrate 2 is partially covered with the second substrate 3 (the left side surface in FIG. 2).

  The first substrate 2 includes a plurality of first insulating layers 21 stacked in the thickness direction, a plurality of first wiring portions 22 disposed on the plurality of first insulating layers 21, and a plurality of first insulating layers 21. And a plurality of first via conductors 23 penetrating in the thickness direction, and a first conductive portion 24.

  Each of the plurality of first insulating layers 21 is a ceramic base material. Examples of the ceramic constituting the first insulating layer 21 include alumina, beryllia, aluminum nitride, boron nitride, silicon nitride, and glass. These ceramics can be used alone or in combination of two or more.

  The plurality of first wiring portions 22 are conductive members that are respectively disposed on the plate surfaces of the plurality of first insulating layers 21. That is, the plurality of first wiring portions 22 are provided as a plurality of conductive layers that are spaced apart in the thickness direction. The plurality of first wiring portions 22 include electrodes (not shown) connected to external terminals.

  In the present embodiment, the plurality of first wiring parts 22 are formed between the plurality of first insulating layers 21 and the first insulating layer 21 constituting the outermost layer (the uppermost layer and the lowermost layer in FIG. 2). Are provided on the exposed surface (that is, the plate surface of the first substrate 2). Note that the plurality of first wiring portions 22 do not necessarily have to be disposed on all the first insulating layers 21.

  The first conduction portion 24 is provided on the side surface of the first substrate 2 where the second substrate 3 is disposed. That is, the first conductive portion 24 is exposed from the side surface of the first substrate 2 in a state where the second substrate 3 is not disposed.

  The first conduction portion 24 is a so-called half via formed by a part of a via conductor in which a through hole penetrating one first insulating layer 21 in the thickness direction is filled with a conductive material. That is, the first conductive portion 24 is a pad-like portion that extends in the thickness direction of the first substrate 2 on the side surface of the first substrate 2. The first conduction part 24 is connected to at least one wiring part among the plurality of first wiring parts 22.

  The plurality of first via conductors 23 includes a first wiring part 22 provided on the surface of one first insulating layer 21 and a first wiring part 22 provided on the back surface of the first insulating layer 21. The insulating layer 21 is connected in the thickness direction to conduct.

  The 1st wiring part 22, the 1st via conductor 23, and the 1st conduction | electrical_connection part 24 contain a metal as a main component. Examples of the metal include tungsten (W), molybdenum (Mo), manganese (Mn), copper (Cu), silver (Ag), and alloys thereof. The “main component” means the most contained component, for example, a component contained in 80% by mass or more.

<Second substrate>
The second substrate 3 is a sheet-like member having two opposing plate surfaces. The second substrate 3 covers a part of the side surface of the first substrate 2 over the entire thickness direction of the first substrate 2 by one plate surface (hereinafter also referred to as “first plate surface”).

  The second substrate 3 includes one second insulating layer 31, two second wiring portions 32 disposed on the front and back surfaces of the second insulating layer 31, and one second penetrating the second insulating layer 31 in the thickness direction. And a second via conductor 33.

  The second insulating layer 31 is a ceramic substrate similar to the first insulating layer 21 of the first substrate 2. The surface of the second insulating layer 31 constitutes a second plate surface opposite to the first plate surface of the second substrate 3, and the back surface of the second insulating layer 31 constitutes the first plate surface of the second substrate 3. To do.

  Of the two second wiring parts 32, the wiring part provided on the second plate surface (that is, the surface of the second insulating layer 31) includes an electrode part 34. The electrode part 34 is a pad-like electrode for connecting an electronic component.

  Of the two second wiring portions 32, the wiring portion provided on the first plate surface (that is, the back surface of the second insulating layer 31) includes a second conduction portion 35. The second conduction part 35 is a pad-like electrode that is electrically connected to the first conduction part 24.

  The two second wiring portions 32 are electrically connected by the second via conductor 33. Therefore, the electrode part 34 is electrically connected to the first conduction part 24 via the second via conductor 33 and the second conduction part 35. Therefore, the electrode part 34 is electrically connected to the plurality of first wiring parts 22 of the first substrate 2. The material of the second wiring part 32 and the second via conductor 33 is the same as that of the first wiring part 22 and the first via conductor 23 of the first substrate 2.

[1-2. Wiring board manufacturing method]
Next, a method for manufacturing the wiring board 1 will be described.
As shown in FIG. 3, the manufacturing method of the wiring board 1 includes a substrate forming step S10, a pressure applying step S20, and a firing step S30.

<Substrate formation process>
In this step, the unsintered first substrate 2 and second substrate 3 in which the insulating layer and the wiring portion are not baked are formed.

  In this step, first, an unsintered ceramic is formed into a ceramic substrate. Specifically, first, ceramic powder, an organic binder, a solvent, and additives such as a plasticizer are mixed to obtain a slurry. Next, this slurry is formed into a sheet by a known method, whereby a substrate-like unsintered ceramic (so-called ceramic green sheet) is obtained.

  A through hole for forming a via conductor is provided in the obtained ceramic green sheet. Then, the 1st unsintered conductor used as a via conductor is filled. The first unsintered conductor is a paste made by adding a solvent or the like to the constituent material of the via conductor. As a method of filling the plurality of holes of the first unsintered conductor, a known paste printing method can be used.

  After the filling of the first unsintered conductor, the second unsintered conductor serving as the wiring portion is disposed on both sides or one side of the ceramic green sheet. As a specific procedure, for example, the second green conductor layer is formed by printing the paste used for filling the first green conductor on the ceramic green sheet by screen printing.

  By cutting the ceramic green sheet on which the second unsintered conductor layer is formed and stacking a plurality of ceramic green sheets as necessary, the unsintered first substrate 2 and the unsintered second substrate 3 are obtained. can get.

  In the process of forming the unsintered first substrate 2, the first conductive portion 24, which is a half via, is cut by cutting the first unsintered conductor filled in the through hole along a plane parallel to the axis of the through hole. An unsintered conductor is formed.

<Pressing process>
In this step, as shown in FIG. 4, the unsintered second substrate 3 is pressed against the side surface of the unsintered first substrate 2. The unsintered second substrate 3 is pressed so that the first plate surface covers the side surface of the unsintered first substrate 2. Further, the unsintered second substrate 3 is disposed at a position where the second conductive portion 35 contacts the first conductive portion 24.

<Baking process>
In this step, the pressed unsintered first substrate 2 and unsintered second substrate 3 are fired. This firing is performed by heating to a temperature at which the ceramic green sheet is sintered. Thereby, the ceramic green sheet is sintered and an insulating layer made of ceramic is formed. In addition, the unsintered conductor is sintered, and the electrically connected via conductor and wiring portion are formed. Furthermore, the side surface of the first substrate 2 and the first plate surface of the second substrate 3 are firmly bonded by firing.

[1-3. effect]
According to the embodiment detailed above, the following effects can be obtained.
(1a) The second substrate 3 on which the second wiring part 32 including the electrode part 34 to which an electronic component or the like is connected is coated on the side surface of the first substrate 2, thereby The electrode portion 34 can be disposed on the side surface of the wiring substrate 1 while being electrically connected to the one wiring portion 22. In addition, by providing the second substrate 3, the degree of freedom in designing the second wiring portion 32, and hence the electrode portion 34, can be increased as compared with the case where the wiring pattern is directly formed on the side surface of the wiring substrate.

  (1b) Since the first conduction portion 24 is a half via, the first conduction portion 24 can be easily formed, and the conduction area with the second conduction portion 35 is secured to increase the reliability of electrical connection. be able to.

[2. Second Embodiment]
[2-1. Wiring board]
A wiring substrate 101 shown in FIG. 5 includes a first substrate 2 and a second substrate 103. Since the first substrate 2 is the same as the first substrate 2 of the wiring substrate 1 in FIG. 2, the same reference numerals are given and description thereof is omitted.

<Second substrate>
The second substrate 103 has a plurality of second insulating layers 31 stacked in the thickness direction, a plurality of second wiring portions 32 arranged in the plurality of second insulating layers 31, and a plurality of second insulating layers 31. And a plurality of second via conductors 33 penetrating in the direction.

  The second substrate 103 is obtained by further providing a second insulating layer 31 on the second plate surface side of the second substrate 3 of the wiring substrate 1 of FIG. Of the plurality of second wiring parts 32, the wiring part provided on the second plate surface of the second substrate 103 includes an electrode part 34. Further, among the plurality of second wiring parts 32, the wiring part provided on the first plate surface of the second substrate 103 includes a second conduction part 35.

  The electrode part 34 and the second conduction part 35 are electrically connected by the plurality of second via conductors 33 and the second wiring part 32 disposed between the plurality of second insulating layers 31. Further, the second conduction part 35 is electrically connected to the first conduction part 24 of the first substrate 2.

[2-2. effect]
According to the embodiment detailed above, the following effects can be obtained.
(2a) Since the second substrate 103 has a multilayer structure, a more complicated wiring pattern can be formed on the second substrate 103. For this reason, the degree of freedom in design in handling the connecting electrode portion 34 is further increased.

[3. Third Embodiment]
[3-1. Wiring board]
A wiring substrate 201 shown in FIG. 6 includes a first substrate 202 and a second substrate 203.

<First substrate>
The first substrate 202 includes a plurality of first insulating layers 21 and 221 stacked in the thickness direction, a plurality of first wiring portions 22 arranged in the plurality of first insulating layers 21, and a plurality of first insulating layers 21. And a plurality of first via conductors 23 penetrating in the thickness direction, and a first conductive portion 24.

  2 except that the first substrate 202 has a first insulating layer 221 extending as a top surface layer on the back surface side so as to protrude in the plate surface direction from the other first insulating layers 21. The configuration is the same as that of one substrate 2. However, the first substrate 202 is covered with the second substrate 203 on two opposing portions (the left side surface and the right side surface in FIG. 6) of the side surfaces and one plate surface.

<Second substrate>
The second substrate 203 includes a plurality of second insulating layers 231 stacked in the thickness direction, a plurality of second wiring portions 32 disposed in the plurality of second insulating layers 231, and a plurality of second insulating layers 231 having a thickness. And a plurality of second via conductors 33 penetrating in the direction.

  The second substrate 203 is disposed so as to cover the side surface of the first substrate 202 and the plate surface of the first substrate 202. Specifically, the second substrate 203 is continuous with the plate surface among the first portion on the side surface of the first substrate 202, the plate surface of the first substrate 202, and the side surface of the first substrate 202, and the first substrate 202. It arrange | positions so that the 2nd part facing a part may be straddled. Note that one end of the second substrate 203 is in contact with the plate surface of the first insulating layer 221.

  Of the plurality of second wiring portions 32 of the second substrate 203, the wiring portion provided on the second plate surface opposite to the first substrate 202 includes an electrode portion 34. Further, among the plurality of second wiring parts 32, the wiring part provided on the first plate surface in contact with the first substrate 202 includes the second conduction part 35.

  As shown in FIG. 6, the second wiring portion 32 provided on the second plate surface extends from a position facing the side surface of the first substrate 202 to a position facing the plate surface of the first substrate 202. It may be. Further, even if the second wiring portion 32 disposed between the plurality of second wiring portions 32 extends from a position facing the side surface of the first substrate 202 to a position facing the plate surface of the first substrate 202. Good.

[3-2. Wiring board manufacturing method]
The manufacturing method of the wiring board 201 is the same as the manufacturing method of the wiring board 1 shown in FIG. Hereinafter, the pressing step S20 in the method for manufacturing the wiring board 201 will be described in detail.

  As shown in FIG. 7, in the pressing step S <b> 20, the unsintered second substrate 203 is pressed in the thickness direction of the first substrate 202 from the plate surface side of the unsintered first substrate 202. The unsintered second substrate 203 is bent along the outer shape of the first substrate 202 so that the first plate surface covers the side surface and the plate surface of the unsintered first substrate 202. In addition, the unsintered second substrate 203 is disposed at a position where the second conductive portion 35 contacts the first conductive portion 24.

[3-3. effect]
According to the embodiment detailed above, the following effects can be obtained.
(3a) Since the area of the second substrate 203 is increased, the degree of freedom in designing the wiring pattern on the second substrate 203 is further increased. Therefore, the adjustment of the impedance of the wiring board 201 is facilitated.

[4. Other Embodiments]
As mentioned above, although embodiment of this indication was described, it cannot be overemphasized that this indication can take various forms, without being limited to the above-mentioned embodiment.

  (4a) In the wiring boards 1, 101, and 201 of the above embodiment, the first conduction part 24 is not limited to a half via. Therefore, the first conductive portion 24 may be a pad electrode other than the via conductor.

  (4b) In the wiring boards 1, 101, and 201 of the above embodiment, the second substrates 3, 103, and 203 have the second conductive part 35, i. The second wiring portion 32 provided on one plate surface may not be provided. For example, the second via conductor 33 that penetrates the second insulating layer 31 that constitutes the first plate surface (that is, abuts against the first substrate 2, 202) may be directly connected to the first conduction portion 24.

  (4c) In the wiring substrates 1, 101, and 201 of the above embodiment, the material of the first insulating layer 21 and the second insulating layers 31 and 231 is not limited to ceramic. For example, the first insulating layer 21 and the second insulating layers 31 and 231 may be made of resin.

  (4d) In the wiring boards 1, 101, and 201 of the above-described embodiment, electronic parts are not necessarily mounted on the electrode part 34. For example, an external terminal may be connected to the electrode part 34 and an electronic component may be mounted on the electrode included in the first wiring part 22.

  (4e) In the method for manufacturing a wiring board according to the above-described embodiment, the via conductor and the wiring portion may be formed using plating. Moreover, you may press-fit using the sintered 1st board | substrate and 2nd board | substrate.

  (4f) The functions of one component in the above embodiment may be distributed as a plurality of components, or the functions of a plurality of components may be integrated into one component. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

DESCRIPTION OF SYMBOLS 1 ... Wiring board, 2 ... 1st board | substrate, 3 ... 2nd board | substrate, 21 ... 1st insulating layer, 22 ... 1st wiring part,
23 ... 1st via conductor, 24 ... 1st conduction | electrical_connection part, 31 ... 2nd insulating layer, 32 ... 2nd wiring part,
33 ... 2nd via conductor, 34 ... Electrode part, 35 ... 2nd conduction | electrical_connection part, 101 ... Wiring board,
103 ... 2nd board | substrate, 201 ... Wiring board, 202 ... 1st board | substrate, 203 ... 2nd board | substrate,
221: first insulating layer, 231: second insulating layer.

Claims (4)

A first substrate having a plurality of first insulating layers stacked in a thickness direction, and a plurality of first wiring portions disposed in the plurality of first insulating layers;
A second substrate having at least one second insulating layer and at least one second wiring portion disposed in the at least one second insulating layer;
With
The second substrate is disposed so as to cover at least a part of the side surface of the first substrate with a plate surface;
The first substrate has a conduction portion provided on the side surface of the first substrate on which the second substrate is disposed.
The second wiring part is a wiring board including an electrode part provided on the second substrate and electrically connected to the conduction part.   The wiring board according to claim 1, wherein the conductive portion is a via conductor that penetrates the first insulating layer in a thickness direction.   The said 2nd board | substrate has the said some 2nd insulating layer accumulated in the thickness direction, and the said some 2nd wiring part arrange | positioned at these 2nd insulating layers. Wiring board as described in.   4. The device according to claim 1, wherein the second substrate is disposed so as to cover at least a part of a plate surface of the first substrate in addition to at least a part of the side surface of the first substrate. The wiring board according to item.

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