JP6060722B2 - Electronic components - Google Patents

Description

  The present invention relates to an electronic component in which an electronic board and a multilayer board are electrically and mechanically connected by a conductive member.

  Conventionally, for example, as shown in Patent Document 1, a printed circuit board having a plurality of mounting pads provided with concave via holes and on which a surface-mounted device is mounted via a plurality of solder balls has been proposed. In this printed circuit board, the surface mounting device is mounted on the printed circuit board through the manufacturing method described below. First, cream solder is screen-printed on a mounting pad. Next, a surface mount device is mounted on the cream solder via a solder ball. Finally, the printed circuit board is heated to a temperature at which cream solder melts by a reflow process by heating. Thus, the surface mounting device is bonded to the mounting pad on the printed circuit board by melting the solder balls and cream solder, and mounted on the printed circuit board.

JP 2009-218435 A

  By the way, in the printed circuit board shown in Patent Document 1, the depth of the concave via hole is deeper than the thickness of the mounting pad. Therefore, there is a possibility that air in the concave via hole is contained as bubbles in melted cream solder and solder balls (hereinafter referred to as solder paste). When the solder paste is solidified while air bubbles are contained in the solder paste, locally low strength portions are formed in the solder balls and the solder paste. Therefore, there is a possibility that the electrical and mechanical connection reliability between the printed circuit board and the surface mount device is lowered.

  In view of the above problems, an object of the present invention is to provide an electronic component in which a decrease in electrical and mechanical connection reliability is suppressed.

In order to achieve the above object, the present invention electrically and mechanically connects an electronic substrate (10), a multilayer substrate (30) on which the electronic substrate is mounted, and the electronic substrate and the multilayer substrate. An electronic component having a conductive member (50), the electronic substrate having a substrate (11) and an electrode (12) formed on a surface (11a) of the substrate facing the multilayer substrate; The multilayer substrate connects the insulating layer (31), the internal wiring (32) formed inside the insulating layer, the external wiring (33) formed outside the insulating layer, and the internal wiring and the external wiring. The conductive member is formed by vaporization of the solvent contained in the conductive paste, and the electrode and the external wiring are electrically and mechanically connected via the conductive member, In the external wiring, in order to secure the thickness of the conductive member, locally recessed dents ( 5) is formed in a position opposed to the via, the recessed portion, a portion of the conductive member is provided, in a thickness direction perpendicular to the opposing surface of the substrate, the depth of the recessed portion (T2) is It is characterized by being shallower than the thickness (T1) of the external wiring.

  Thus, according to the present invention, in the thickness direction, the depth (T2) of the recess (35) is shallower (shorter) than the thickness (T1) of the external wiring (33). According to this, bubbles are less likely to be included in the conductive member (50) compared to a configuration in which the depth of the recess is deeper (longer) than the thickness of the external wiring. In the present invention, a conductive paste is used as the conductive member (50). According to this, the amount of the conductive member (50) provided outside the recess (35) is reduced as compared with the configuration in which the conductive paste and the solder balls are used as the conductive member (50). Therefore, it becomes difficult for bubbles to be contained in the conductive member (50). As a result, the formation of locally low strength portions on the conductive member (50) is suppressed, and electrical and mechanical connection reliability between the electronic substrate (10) and the multilayer substrate (30) is improved. Decrease is suppressed.

  Furthermore, unlike the configuration in which the depth of the recess is deeper (longer) than the thickness of the external wiring, the recess (35) is connected to the external wiring (33) without depending on the arrangement position of the via (34). Can be formed. In addition, the number of recesses (35) can be determined without depending on the number of vias (34). The depth of the recess (35) is the distance from the open end of the recess (35) to the bottom.

It is a top view which shows schematic structure of the electronic component which concerns on 1st Embodiment. It is sectional drawing which follows the II-II line | wire of FIG. It is sectional drawing which follows the III-III line of FIG. It is an expanded sectional view for demonstrating the depth of a dent part. It is an expanded sectional view which shows another form of a dent part. It is sectional drawing which shows the modification of an electronic component. It is sectional drawing which shows the modification of an electronic component. It is sectional drawing which shows the modification of an electronic component. It is sectional drawing which shows the modification of an electronic component. It is sectional drawing which shows the modification of an electronic component. It is sectional drawing which shows the modification of an electronic component.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
The electronic component according to the present embodiment will be described with reference to FIGS. In FIG. 1, the conductive member 50 is omitted, and a portion hidden by the electronic substrate 10 is indicated by a broken line. In the following, three directions that are orthogonal to each other are referred to as an x direction, a y direction, and a z direction. The z direction corresponds to the thickness direction described in the claims, and the direction parallel to the xy plane defined by the x direction and the y direction corresponds to the plane direction described in the claims. .

  As shown in FIGS. 1 to 3, the electronic component 100 includes an electronic substrate 10, a multilayer substrate 30, and a conductive member 50. The electronic substrate 10 is mounted on the multilayer substrate 30, and the electronic substrate 10 and the multilayer substrate 30 are electrically and mechanically connected via the conductive member 50.

  The electronic substrate 10 includes a substrate 11 and an electrode 12 formed on the substrate 11. The substrate 11 has a rectangular parallelepiped shape, and a surface 11a of the substrate 11 facing the multilayer substrate 30 has a rectangular shape. As shown in FIG. 2, the electrode 12 has a U-shaped cross section in the xz plane defined by the x direction and the z direction, and the opposing surface 11 a of the substrate 11, its back surface 11 b, and It is formed on each of the side surfaces 11c that connect the surfaces 11a and 11b. A portion of the electrode 12 formed on the facing surface 11a faces the multilayer substrate 30, and a conductive member 50 is provided between the two.

  The multilayer substrate 30 includes an insulating layer 31, an internal wiring 32 formed inside the insulating layer 31, an external wiring 33 formed outside the insulating layer 31, a via 34 connecting the wirings 32, 33, A build-up board having The external wiring 33 is formed with a recessed portion 35 that is locally recessed in order to ensure the thickness of the conductive member 50. As shown in FIG. 1, in the xy plane, the recess 35 is circular, and as shown in FIG. 4, in the z direction, the depth T2 of the recess 35 (from the opening end to the bottom of the recess 35). The distance T2) is shallower (shorter) than the thickness T1 of the external wiring 33. Further, the width d of the recess 35 in the direction parallel to the xy plane is directly proportional to the distance D (the width D of the electronic substrate 10 shown in FIG. 1) between the center CP of the electronic substrate 10 and a remote part to be described later. Are in a relationship.

  The remote site is a site farthest from the center CP on the facing surface 11a. Moreover, the said opposing surface 11a has comprised the rectangle. Therefore, the remote site corresponds to each of the four corners of the facing surface 11a, and the width D of the electronic substrate 10 corresponds to half the length of the diagonal line of the facing surface 11a. In the present embodiment, the same number of recesses 35 as the four remote parts are formed in the external wiring 33. All of the four remote parts are opposed to the corresponding recesses 35 with the conductive member 50 interposed therebetween.

  As shown in FIG. 1, the outer surface 33 a of the external wiring 33 is divided into a region facing the electronic substrate 10 and a region not facing the electronic substrate 10. As shown in FIGS. 2 and 3, the conductive member 50 is provided in each of the opposing region and the non-opposing region of the outer surface 33 a, and the electrode 12 and the external wiring 33 are electrically and mechanically connected via the conductive member 50. It is connected. As shown in FIG. 1, the shape of the periphery of the recess 35 in the non-facing region of the external wiring 33 forms a semicircle, and the periphery of the recess 35 is surrounded. Thereby, the opposing part with the remote part in an opposing area | region is adjacent to the area | region away from the remote part in a non-opposing area | region in the y direction.

  The conductive member 50 is formed by vaporizing a solvent contained in the conductive paste. A conductive paste is applied to the external wiring 33, and the electronic substrate 10 is mounted on the conductive paste. Then, the entire electronic substrate 100 is heated. As a result, the conductive paste wets and spreads, and the portion formed on the side surface 11c of the electrode 12 is also covered with the conductive paste. A part of the external wiring 33 forms a semicircle and surrounds the periphery of the recess 35. As shown in FIG. 3, the conductive paste provided in the semicircular part wets and spreads on the part formed on the side surface 11 c of the electrode 12. As a result, the conductive member 50 is formed, and the electronic substrate 10 and the multilayer substrate 30 are electrically and mechanically connected via the conductive member 50.

  Next, functions and effects of the electronic component 100 according to the present embodiment will be described. As described above, in the z direction, the depth T2 of the recess 35 is shallower (shorter) than the thickness T1 of the external wiring 33. According to this, bubbles are less likely to be contained in the conductive member 50 as compared with a configuration in which the depth of the recess is deeper (longer) than the thickness of the external wiring. Further, a conductive paste is used as the conductive member 50. According to this, the amount of the conductive member 50 provided outside the recessed portion 35 is reduced as compared with the configuration in which the conductive paste and the solder ball are used as the conductive member 50. Therefore, it is difficult for bubbles to be contained in the conductive member 50. As a result, the formation of locally low-strength portions on the conductive member 50 is suppressed, and the electrical and mechanical connection reliability between the electronic substrate 10 and the multilayer substrate 30 is suppressed from decreasing. The

  Further, unlike the configuration in which the depth of the recess is deeper (longer) than the thickness of the external wiring, the recess 35 is connected to the external wiring without depending on the arrangement position of the via 34 as shown in FIG. 33 can be formed. Further, the number of the recessed portions 35 can be determined without depending on the number of the vias 34.

  A stress caused by a difference in thermal expansion coefficient between the electronic substrate 10 and the multilayer substrate 30 is applied to the conductive member 50 due to a change in environmental temperature. The stress generated in the conductive member 50 increases as the distance from the center CP increases. For this reason, the greatest stress is generated in the remote part farthest from the center CP in the facing surface 11a. On the other hand, in this embodiment, the remote site where the greatest stress is generated is opposed to the recess 35 via the conductive member 50. Thereby, the remote site where the greatest stress is generated is fixed by the conductive member 50 having a thickness corresponding to the depth of the recess 35. As described above, since the strength of the conductive member 50 is increased, fatigue of the conductive member 50 is suppressed. Thereby, it is suppressed that the electrical and mechanical connection reliability between the electronic substrate 10 and the multilayer substrate 30 is lowered.

  All of the plurality of remote parts and the corresponding recesses 35 are opposed to each other through the conductive member 50. According to this, compared with the configuration in which one of a plurality of remote parts and only one corresponding recess are opposed to each other through the conductive member, the conductive member 50 is exhausted, and the electronic substrate 10 and the multilayer substrate are It is suppressed that the electrical and mechanical connection reliability with 30 decreases.

  The shape of the periphery of the recess 35 in the non-opposing region of the external wiring 33 forms a semicircle, and surrounds the periphery of the recess 35. Then, the conductive paste provided on the semicircular portion wets and spreads on the portion of the electrode 12 formed on the side surface 11c. Thereby, the conductive member 50 is provided around the remote part of the electronic substrate 10, and the strength of the conductive member 50 is increased. As a result, exhaustion of the conductive member 50 is suppressed, and a decrease in electrical and mechanical connection reliability between the electronic substrate 10 and the multilayer substrate 30 is suppressed.

  The width d of the recess 35 in the direction parallel to the xy plane is directly proportional to the distance between the center CP of the electronic substrate 10 and the remote part. When the distance between the center CP of the electronic substrate 10 and the remote portion, that is, the width D of the electronic substrate 10 is increased, the stress generated at the remote portion is caused by the difference in thermal expansion coefficient between the electronic substrate 10 and the multilayer substrate 30. growing. Therefore, as described above, the width d of the recess 35 is set to be in direct proportion to the width D of the electronic substrate 10. Thereby, the strength of the conductive member 50 is improved, and the connection strength between the electronic substrate 10 and the multilayer substrate 30 is improved. As a result, even if the physique (width D) of the electronic substrate 10 increases, the strength of the conductive member 50 increases accordingly. As a result, the fatigue of the conductive member 50 is suppressed, and the electrical and mechanical connection reliability between the electronic substrate 10 and the multilayer substrate 30 is suppressed from decreasing.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the present embodiment, an example in which the recessed portion 35 is circular in the xy plane is shown. However, the shape of the recess 35 in the xy plane is not limited to the above example. For example, as shown in FIGS. 6 to 9, a rectangle, an L shape, an ellipse, a U shape, or the like can be adopted.

  As shown in FIG. 7, each of the four recessed portions 35 facing the remote site is formed by connecting a first recessed portion 36 and a second recessed portion 37 so as to form an L shape. The first recess 36 has a linear shape in which a part of the external wiring 33 is locally recessed so as to be along one of the two long sides forming the facing surface 11a. The second recessed portion 37 has a linear shape in which a part of the external wiring 33 is locally recessed so as to be along one of the two short sides forming the facing surface 11a. A connection point between the first dent portion 36 and the second dent portion 37 faces the remote site via the conductive member 50.

  According to this, unlike the configuration in which the recessed portion 35 faces only the remote part, the thickness of the conductive member 50 that connects the four sides of the electronic substrate 10 to the multilayer substrate 30 is set to the first recessed portion 36 and the second recessed portion 35. The thickness can be increased by the amount of the recessed portion 37. Therefore, the strength of the conductive member 50 is increased, and fatigue of the conductive member 50 is suppressed. Thereby, it is suppressed that the electrical and mechanical connection reliability between the electronic substrate 10 and the multilayer substrate 30 is lowered.

  More specifically, the connection strength between the electronic substrate 10 and the multilayer substrate 30 can be set to the same level as that of the configuration in which the recessed portion 35 forms a rectangle whose length of one side is equal to the length of each of the recessed portions 36 and 37. Moreover, since the shape of the recessed part 35 is small compared with the above-mentioned comparative structure, the formation process of the recessed part 35 is simplified. As a result, the manufacturing cost is reduced.

  In this embodiment, the same number of recesses 35 as the four remote parts are formed in the external wiring 33, and all four remote parts are opposed to the corresponding recesses 35 via the conductive member 50. Indicated. However, as shown in FIG. 8, a configuration in which the recessed portion 35 is formed in the external wiring 33 can be adopted separately from the recessed portion 35 corresponding to the remote site. In FIG. 8, an intermediate part between two remote parts adjacent in the direction along the edge of the opposing surface 11 a faces the recess 35 via the conductive member 50.

  According to this, unlike the configuration in which the recessed portion 35 faces only the remote portion, the thickness of the conductive member 50 that connects the intermediate portion of the electronic substrate 10 to the multilayer substrate 30 is set to the thickness of the recessed portion 35 that faces the intermediate portion. Minutes, can be thickened. The stress caused by the difference in thermal expansion coefficient between the electronic substrate 10 and the multilayer substrate 30 is caused by the conductive member 50 provided in the recess 35 facing the remote part and the conductive member 50 provided in the recess 35 facing the intermediate part. Applied to each. Therefore, the stress applied to the conductive member 50 provided in the recess 35 facing the remote site is weakened. Thereby, it is suppressed that the conductive member 50 is exhausted and the electrical and mechanical connection reliability between the electronic substrate 10 and the multilayer substrate 30 is reduced. Note that the configuration shown in FIG. 9 can be employed to achieve the same effects as the configuration shown in FIG. In FIG. 9, the dent part 35 facing the remote part shown in FIG. 8 and the dent part 35 facing the intermediate part are connected to each other.

  In the present embodiment, as shown in FIG. 1, an example in which the multilayer substrate 30 has two external wirings 33 is shown. However, the number of external wirings 33 is not limited to the above example. For example, as shown in FIGS. 10 and 11, a configuration in which the multilayer substrate 30 includes three external wirings 33 may be employed.

  In the present embodiment, the material for forming the substrate 11 is not particularly mentioned. However, as a material for forming the substrate 11, a semiconductor, ceramic, or the like can be used.

  In the present embodiment, the electrode 12 has a U-shaped cross-sectional shape in the xz plane, and the opposing surface 11a of the substrate 11, the back surface 11b thereof, and the side surface 11c connecting the surfaces 11a and 11b, respectively. The example formed is shown. However, the shape of the electrode 12 is not limited to the above example, and may be at least formed on the facing surface 11a.

  In this embodiment, the example in which the recessed part 35 was formed in multiple numbers by the external wiring 33 was shown. However, the number of the recessed portions 35 is not limited to the above example, and may be a single number.

DESCRIPTION OF SYMBOLS 10 ... Electronic substrate, 11 ... Board | substrate, 11a ... Opposite surface, 12 ... Electrode, 30 ... Multilayer substrate, 31 ... Insulating layer, 32 ... Internal wiring, 33 ... External wiring, 34 ... via, 35 ... dent, 50 ... conductive member, T1 ... thickness of external wiring, T2 ... depth of recess, 100 ... electronic component

Claims (8)

An electronic substrate (10);
A multilayer substrate (30) on which the electronic substrate is mounted;
An electronic component having a conductive member (50) for electrically and mechanically connecting the electronic substrate and the multilayer substrate,
The electronic substrate has a substrate (11) and an electrode (12) formed on a surface (11a) of the substrate facing the multilayer substrate,
The multilayer substrate includes an insulating layer (31), an internal wiring (32) formed inside the insulating layer, an external wiring (33) formed outside the insulating layer, the internal wiring, and the external wiring. A via (34) for connecting the wiring,
The conductive member is formed by vaporizing a solvent contained in a conductive paste,
The electrode and the external wiring are electrically and mechanically connected via the conductive member,
In the external wiring, in order to ensure the thickness of the conductive member, a locally recessed dent (35) is formed at a position facing the via ,
A part of the conductive member is provided in the recess,
In the thickness direction orthogonal to the facing surface of the substrate, the depth (T2) of the recess is shallower than the thickness (T1) of the external wiring.   2. The electronic component according to claim 1, wherein a remote part farthest from the center (CP) of the electronic substrate on the opposing surface of the substrate is opposed to the recess through the conductive member. There are a plurality of the remote parts,
A plurality of the recesses are formed in the external wiring,
3. The electronic component according to claim 2, wherein all of the plurality of remote parts are opposed to the corresponding recesses through the conductive member. The electrode is formed not only on the facing surface, but also on a side surface (11c) connecting the facing surface and the back surface (11b) of the substrate,
The outer surface of the external wiring is composed of a region facing the electronic substrate and a region not facing the electronic substrate, and the region facing the remote region in the facing region is adjacent to the non-facing region. And
The electronic component according to claim 2, wherein the conductive member is provided on each of the opposing region, the non-opposing region, and the electrode formed on the side surface.   The width (d) of the recess in a plane direction perpendicular to the thickness direction is directly proportional to a distance (D) between the center of the electronic substrate and the remote part. Electronic component of any one of 2-4. The substrate forms a rectangular parallelepiped,
The opposing surface of the substrate has a rectangular shape,
The electronic component according to claim 2, wherein each of the four corners of the facing surface corresponds to the remote part. The recessed portion facing the remote part includes a first recessed portion in which a part of the external wiring is locally recessed so as to be along one of the two long sides forming the facing surface, and the facing surface A second recessed portion in which a part of the external wiring is locally recessed so as to be along one of the two short sides forming the shape.
The electronic component according to claim 6, wherein a connection point between the first dent portion and the second dent portion is opposed to the remote site via the conductive member. Apart from the dent corresponding to the remote part, the dent is formed in the external wiring,
The intermediate part between two said remote parts adjacent in the direction along the edge of the said opposing surface is facing the said recessed part through the said electrically-conductive member, The Claim 6 or Claim 7 characterized by the above-mentioned. The electronic component described.

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