JP2017079258A - Electronic part-mounting board and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic part-mounting board, etc. with high reliability in lead terminal-connection pad boding.SOLUTION: An electronic part-mounting board 10 comprises: an insulative substrate 1 having an upper surface including an electronic part-mounting portion 1a and a lower surface; a connection pad 2 provided on an outer peripheral portion of at least one surface of the upper and lower surfaces of the insulative substrate 1; and a lead terminal 4 having an end portion 4a bonded to the connection pad 2 by a brazing filler metal 3. In the electronic part-mounting board, a concave portion 5 having a portion, which overlaps with the end portion 4a of the lead terminal 4 in top or backside view, is provided on the portion of the at least one surface of the upper and lower surfaces of the insulative substrate 1, where the connection pad 2 is provided; and a metal layer 6 is provided on an inner surface of the concave portion 5, to which part of the brazing filler metal 3 is bonded. In the concave portion 5, a puddle of the brazing filler metal 3 with a meniscus is formed and therefore, the electronic part-mounting board is useful for the increase in connection strength and the increase in bonding reliability by the distribution of a stress.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic component mounting board on which electronic components are mounted, and an electronic device including the electronic component mounting board.

  As an electronic component mounting board on which various electronic components such as a semiconductor element, a capacitive element and a piezoelectric element are mounted, it has an electronic component mounting portion on the upper surface of the insulating substrate and is used for external connection on the upper surface or the lower surface of the insulating substrate What has the terminal of this is used. The insulating substrate is a flat plate member made of, for example, a ceramic sintered body. As the terminal, a strip-like lead terminal is used. In general, the lead terminal is joined to a connection pad provided on the outer peripheral portion of the upper surface or the lower surface of the insulating substrate by a brazing material.

  In addition, the electronic component is mounted on the insulating substrate of the electronic component mounting substrate, and the electronic component and the lead terminal are electrically connected to each other via a wiring conductor or the like provided on the insulating substrate. Produced. The lead terminal of the electronic device is connected to a predetermined part of the external electric circuit, and the electronic component is mounted on the external electric circuit.

Japanese Unexamined Patent Publication No. 7-254763 JP 2012-134301 A

  In the electronic component mounting substrate and the electronic device as described above, since stress such as thermal stress is likely to be concentrated on the joint portion between the connection pad and the lead terminal, improvement in the reliability of the lead terminal joint is a problem. . In particular, in recent years, the bonding area between the connection pad and the lead terminal has been reduced with the miniaturization of the electronic device, and thus the improvement in the reliability of the bonding has become more important.

  For such a problem, for example, a portion of the lead terminal connected to the connection pad is bent, and a pool of brazing material and a meniscus are formed in the bent portion, thereby improving the reliability of bonding. Can be considered. However, in this case, since the miniaturized lead terminal is further bent, the productivity of the electronic component mounting substrate and the electronic device may be reduced. Moreover, there is a possibility that a sufficient pool of brazing material is not formed.

  An electronic component mounting substrate according to one aspect of the present invention includes an insulating substrate having an upper surface including a mounting portion for the electronic component, a connection pad provided on an outer peripheral portion of the upper surface of the insulating substrate, and a brazing material on the connection pad. A lead terminal having an end portion joined by the step, and a concave portion having a portion overlapping the end portion of the lead terminal in a top view in a portion of the upper surface of the insulating substrate provided with the connection pad. And a metal layer to which a part of the brazing material is bonded is provided on the inner surface of the recess.

  An electronic device according to one aspect of the present invention includes the electronic component mounting substrate having the above-described configuration and an electronic component mounted on the mounting portion.

  According to the electronic component mounting substrate of one aspect of the present invention, the recess is provided in the portion of the upper surface of the insulating substrate where the connection pad is provided, and a part of the brazing material is bonded to the inner surface of the recess. Since the metal layer is provided, a brazing material reservoir is formed in the recess. In addition, it is easy to have a structure in which a meniscus is formed in the brazing material joined from the metal layer to the lead terminal in the space in the recess.

  That is, the joint between the connection pad and the lead terminal is effectively reinforced by the joint between the metal layer and the lead terminal, and the thermal stress is effectively dispersed along the meniscus. Therefore, it is possible to provide an electronic component mounting board in which the reliability of bonding between the connection pad and the lead terminal is improved.

  In addition, according to the electronic device of one aspect of the present invention, since the electronic component mounting substrate having the above-described configuration is included, the reliability of the connection between the connection pad and the lead terminal is improved. An electronic device with high reliability such as mounting can be provided.

(A) is a top view which shows the electronic component mounting board | substrate and electronic device of embodiment of this invention, (b) is sectional drawing in the AA of (a). (A) is a top view which expands and shows the principal part of the electronic device shown in FIG. 1, (b) is sectional drawing in the BB line of (a). It is a top view which shows the 1st modification of Fig.2 (a). It is a top view which shows the 2nd modification of Fig.2 (a). It is a top view which shows the 3rd modification of Fig.2 (a). (A) is a top view which shows the 4th modification of Fig.2 (a), (b) is sectional drawing which shows the modification of FIG.2 (b).

  An electronic component mounting board and an electronic device according to embodiments of the present invention will be described with reference to the accompanying drawings. Note that the distinction between the upper and lower sides in the following description is for convenience, and does not prescribe the upper and lower sides when the electronic component mounting board or the like is actually used.

  FIG. 1A is a top view showing an electronic component mounting substrate and an electronic device according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA of FIG. 2A is an enlarged plan view showing the main part of the electronic component mounting substrate and the electronic device shown in FIG. 1, and FIG. 2B is a cross-sectional view taken along line BB in FIG. It is sectional drawing.

  The electronic component mounting board 10 of the embodiment includes an insulating substrate 1 having an upper surface including an electronic component mounting portion 1a, a connection pad 2 provided on the outer peripheral portion of the upper surface of the insulating substrate 1, and a brazing material on the connection pad 2. 3 and a lead terminal 4 having an end portion 4 a joined by 3. In the example shown in FIG. 1, a concave mounting portion 1 a is provided at the center of the upper surface of the insulating substrate 1. In addition, a recess 5 is provided in a portion of the upper surface of the insulating substrate 1 where the connection pad 2 is provided. The recess 5 has a portion that overlaps the end 4a of the lead terminal 4 in a top view. A metal layer 6 to which a part of the brazing material 3 is bonded is provided on the inner surface of the recess 5. In FIG. 1A and FIG. 2A, the brazing material 3 is omitted in order to make the recess 5 and the metal layer 6 easier to see.

  In addition, the electronic device 20 according to the embodiment of the present invention is basically configured by the electronic component mounting substrate 10 having the above-described configuration and the electronic component 21 mounted on the mounting portion 1a of the electronic component mounting substrate 10. . The electronic device 20 is mounted as a component on an electronic device such as a computer, various sensor devices, or a mobile phone.

  In this embodiment, the connection pad 2 and the lead terminal 4 will be described by taking an example in which the connection pad 2 and the lead terminal 4 are provided on the outer peripheral portion of the upper surface of the insulating substrate 1. It may be provided in the part, and may be provided in the outer peripheral part of both the upper surface and the lower surface. Even when the connection pads 2 and the lead terminals 4 are provided on the lower surface of the insulating substrate 1, the same effects as described below can be obtained.

  According to the electronic component mounting substrate 10 of the embodiment, since it has the above configuration, a pool of the brazing material 3 is formed in the recess 5. It is also easy to adopt a structure in which a meniscus is formed in the brazing material 3 joined from the metal layer 6 to the lead terminal 4 in the space in the recess 5.

  That is, the joint between the connection pad 2 and the lead terminal 4 is effectively reinforced by the joint between the metal layer 6 and the lead terminal 4, and the thermal stress is effectively dispersed along the meniscus. Therefore, it is possible to provide the electronic component mounting board 10 in which the connection reliability between the connection pad 2 and the lead terminal 4 is improved.

  Further, according to the electronic device 20 of the embodiment, since the electronic component mounting substrate 10 having the above-described configuration is included, the external electrical circuit (see FIG. 5) in which the connection reliability between the connection pad 2 and the lead terminal 4 is improved. It is possible to provide the electronic device 20 having high reliability such as mounting on a device (not shown). Details of the electronic component mounting substrate 10 and the electronic device 20 will be described below. The brazing material 3 is directly joined to the end portion 4a of the lead terminal 4. However, in the following description, for the sake of simplicity, the brazing material 3 is simply described as joining to the lead terminal 4. There is.

  The insulating substrate 1 has a square plate shape, for example, and has a concave mounting portion 1a at the center of the upper surface. An electronic component 21 is accommodated in the mounting portion 1a. The electronic component 21 is mounted on the bottom surface of the concave portion by, for example, a low melting point solder such as solder or gold-tin solder, or a bonding material (not shown) such as an adhesive. The insulating substrate 1 may have a flat plate shape without such a concave portion, or may have a disk shape or an elliptical plate shape. When the insulating substrate 1 has a flat plate shape, for example, the central portion of the upper surface of the insulating substrate 1 such as a rectangular shape becomes the mounting portion 1a.

  The electronic component 21 includes a semiconductor integrated circuit element such as an IC, an optical semiconductor element such as an LED (light emitting diode), a PD (photodiode), and a CCD (charge coupled device), and a minute electromechanical mechanism on the surface of the semiconductor substrate. Various semiconductor elements such as formed micromachines (so-called MEMS elements) can be mentioned. The electronic component 21 is not limited to a semiconductor element, and may be other electronic components such as a piezoelectric element, a capacitive element, an inductor element, a resistor, and a sensor element. A plurality of electronic components (not shown) may be mounted on the mounting portion 1a, and the plurality of electronic components may be of different types.

  The insulating substrate 1 is formed of a ceramic sintered body selected from, for example, an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a glass ceramic sintered body, and the like. In the example shown in FIG. 1, an insulating substrate 1 is formed by laminating a plurality of insulating layers (without symbols).

If the insulating substrate 1 is made of, for example, an aluminum oxide sintered body, a plurality of ceramic green sheets obtained by forming raw powders such as aluminum oxide and silicon oxide into a sheet shape together with an appropriate organic binder and an organic solvent are laminated. Later, it is manufactured by firing the laminate. In this case, if a part of the plurality of ceramic green sheets is formed into a frame shape by a process such as punching, and this frame-shaped ceramic green sheet is laminated on the upper layer side, the concave mounting portion 1a is formed on the upper surface. An insulating substrate 1 having the same can be manufactured.

  The connection pad 2 provided on the insulating substrate 1 and the lead terminal 4 bonded to the connection pad 2 function as a connection part for electrically and mechanically connecting the electronic device 20 to an external electric circuit. In the electronic component mounting board 10 and the electronic device 20 of this embodiment, the lead terminal 4 is a metal material formed into a strip shape. One end 4 a of the lead terminal 4 is joined to the connection pad 2 by a brazing material 3.

  The connection pad 2 functions as a base metal layer for bonding the lead terminal 4. Since the connection pads 2 are provided on the insulating substrate 1, the joining of the lead terminals 4 to the insulating substrate 1 made of a ceramic sintered body or the like with the brazing material 3 is easy.

  The connection pad 2 is made of, for example, a metal material such as tungsten, molybdenum, manganese, copper, silver, or palladium. Such a metal material adheres on the insulating substrate 1 in the form of a metallized layer or a plated layer. For example, when the connection pad 2 is made of a tungsten metallized layer, a metal paste formed by adding and kneading an organic solvent and a binder to tungsten powder is printed in a predetermined pattern on a ceramic green sheet to be the insulating substrate 1. Thereafter, the connection pads 2 can be formed by simultaneously performing these. The metal paste can be printed by a printing method such as a screen printing method.

  The electrical connection between the electronic component 21 mounted on the mounting portion 1a and the connection pad 2 is performed by, for example, a wiring conductor (not shown) provided from the mounting portion 1a to the outer peripheral portion of the upper surface of the insulating substrate 1. Can be done. A part of the wiring conductor may be provided inside the insulating substrate 1 or may be a via conductor provided in the thickness direction of the insulating substrate 1.

  The wiring conductor can also be formed by the same method using the same metal material as that of the connection pad 2. For the via conductor, a through hole is provided in advance in the ceramic green sheet serving as an insulating layer of the insulating substrate 1 by mechanical processing or laser processing, and the metal paste similar to the above is filled in the through hole, and at the same time It can be formed by firing.

  In addition, the electrical connection between the electronic component 21 and the wiring conductor can be performed by a low melting point brazing material such as a bonding wire or solder, or a conductive connecting material such as a conductive adhesive. In the example shown in FIG. 1, a bonding wire is used as the conductive connecting material.

  The brazing material 3 is a bonding material for bonding the connection pad 2 and the lead terminal 4 to each other. A part of the brazing material 3 is interposed between the connection pad 2 and the lead terminal 4 and joined to both. Further, the other part of the brazing material 3 may include a material that spreads more outward than between the connection pad 2 and the lead terminal 4. Further, another part of the brazing material 3 is joined to the metal layer 6 in the recess 5. Details of the metal layer 6 and the like will be described later.

  Examples of the brazing material 3 include metal materials such as silver brazing containing a silver-based alloy material such as a silver-copper alloy. The silver solder is, for example, JIS standard B-Ag8.

The joining of the lead terminal 4 to the connection pad 2 by the brazing material 3 can be performed as follows, for example. First, the end portion 4 a of the lead terminal 4 is positioned and set on the connection pad 2 so that the metal material for the brazing material 3 formed into a film is interposed between the connection pad 2 and the lead terminal 4. Next, in a state where these members are temporarily fixed with a jig or an adhesive, the members are heated using an electric furnace or the like and then cooled. Thus, the molten metal material becomes the brazing material 3 between the connection pad 2 and the lead terminal 4, and the connection pad 2 and the lead terminal 4 are joined to each other through the brazing material 3.

  When the connection pad is provided on the lower surface of the insulating substrate 1 (not shown), the insulating substrate 1 is turned upside down, that is, with the connection pad on the lower surface facing upward. What is necessary is just to perform the operation | work of joining (brazing).

  One end portion 4 a of the lead terminal 4 is joined to the connection pad 2 by the brazing material 3. The other end (not indicated) of the lead terminal 4 is electrically and mechanically connected to a predetermined portion of the external electric circuit via solder or the like. As a result, the electronic component 21 can be electrically connected to the external electric circuit.

  In the electronic component mounting substrate 10 and the electronic device 20 of the embodiment, a plurality of connection pads 2 and a plurality of lead terminals 4 are provided. The plurality of connection pads 2 and the plurality of lead terminals 4 are respectively provided corresponding to a plurality of electrodes (not shown) for signals, power supplies, and grounds that the electronic component 21 has, for example.

  In the electronic component mounting substrate 10 and the electronic device 20 of the embodiment, as described above, the concave portion 5 having the above-described configuration is provided on the upper surface of the insulating substrate 1, and the metal layer 6 is provided on the inner surface of the concave portion 5. Is provided. A part of the brazing material 3 is joined to the metal layer 6. The concave portion 5 and the metal layer 6 have a function of increasing the reliability of joining by the brazing material 3 between the lead terminal 4 and the connection pad 2.

  That is, by providing the concave portion 5 and the metal layer 6 having the above-described configuration, a space in which the brazing material 3 can be accommodated below the lead terminal 4 (insulating substrate 1 side) is secured. The brazing material 3 that has entered the space is joined to the metal layer 6. Thereby, the strength of the bonding of the lead terminal 4 to the substrate body (no symbol) in which the connection pad 2 and the metal layer 6 are added to the insulating substrate 1 is improved. Further, a meniscus is easily formed on the brazing material 3 from the space (inside the recess 5) to the lead terminal 4, and stress such as thermal stress is effectively dispersed along the meniscus. Therefore, it is possible to provide the electronic component mounting substrate 10 and the electronic device 20 that are effective in improving the long-term reliability of the bonding of the lead terminals 4 to the substrate body.

  In addition, the joining of the brazing material 3 to the metal layer 6 is performed when the molten metal material for the brazing material 3 flows into the recess 5 when the lead terminal 4 is joined to the connection pad 2 as described above. It is done by spreading wet. The metal material for the brazing material 3 that spreads on the metal layer 6 becomes the brazing material 3 joined to the metal layer 6.

  In the example shown in FIGS. 1 and 2, the recess 5 has a rectangular shape in which corners are formed in an arc shape (an elliptical shape in which a part of the outer periphery is linear along the long axis), but is not limited to this shape. Instead, it may be a polygonal shape including a rectangular shape such as a rectangular shape, a circular shape, or an indefinite shape.

  The size (opening area) of the recess 5 in the top view is within a range having a portion that overlaps the end portion 4a of the lead terminal 4 in the top view, and the workability at the time of formation described later, and the strength of the top surface portion of the insulating substrate 1 And what is necessary is just to set suitably according to conditions, such as the quantity (volume) of the brazing material 3. FIG.

  The depth of the recess 5 depends on the material forming the insulating substrate 1 (particularly, the coefficient of thermal expansion that affects thermal stress), the type of electronic component 21 (heat generation amount), and the type of brazing material 3. These may be set as appropriate in consideration of various conditions such as the above. For example, when the insulating substrate 1 is made of an aluminum oxide sintered body, the brazing material 3 is B-Ag8 silver brazing, and the mounted electronic component 21 is a semiconductor integrated circuit element, the depth of the recess 5 is What is necessary is just to set to about 50-500 micrometers.

  The recess 5 is formed, for example, by drilling a part of a ceramic green sheet to be the insulating substrate 1 to form a through part, and the ceramic green sheet having the through part is formed on the surface layer side (FIGS. 1 and 2). In the example shown in FIG. The punching process for the ceramic green sheet can be performed by a method such as mechanical punching using a die having a punching pin or laser processing.

  In consideration of the formation of the recess 5 by processing as described above, the recess 5 may have a rectangular shape such as a rectangular shape including the shapes shown in FIGS. 1 and 2, an elliptical shape, or a circular shape. From the viewpoint of ease of forming work, it is preferable.

  In addition, the depth of the recess 5 may be set in consideration of the ease of the above-described formation method (formation by the penetration portion of the insulating layer). In this case, the depth of the recess 5 may be set to be the same as the thickness of one insulating layer, for example, 50 to 200 μm.

  Further, the shape of the recess 5 in the longitudinal section (depth section) is rectangular in the example shown in FIGS. 1 and 2, but can be trapezoidal as long as a space for accommodating the brazing material 3 can be secured. Other shapes such as an arc shape or an elliptic arc shape may be used. In other words, the inner surface of the recess 5 is not limited to extending in one direction perpendicular to the upper surface of the insulating substrate 1, but may be inclined in part or all of the vertical direction and curved ( (Not shown). When the inner surface of the recess 5 is inclined or curved, the metal layer 6 provided on the inner surface is also inclined or curved. In this case, for example, the surface of the metal layer 6 can be made into a shape suitable for the accumulation of the brazing material 3 and the formation of the meniscus.

  The metal layer 6 is formed of, for example, the same metal material as that of the connection pad 2. In this case, the metal layer 6 can be formed by applying the same metal paste as described above to the inner side surface of the penetrating portion of the ceramic green sheet to be the recess 5 and simultaneously firing. Application of the metal paste to the inner side surface of the penetrating portion can be performed, for example, by screen printing using vacuum suction.

  The metal layer 6 is provided at least near the upper end of the inner surface of the recess 5 and in the vicinity thereof in consideration of the ease of joining of the brazing material 3, that is, the flowability of the molten metal material for the brazing material 3. It is preferable. Further, the metal layer 6 may be provided from the upper end to the lower end of the inner surface of the recess 5 in consideration of securing the bonding area of the brazing material 3 and workability at the time of formation by screen printing as described above. .

  The thickness of the metal layer 6 should just be the same grade as the connection pad 2, for example. If both the metal layer 6 and the connection pad 2 are made of a metallized layer of tungsten, the thickness of the metal layer 6 and the connection pad 2 is set to about 10 to 40 μm.

  In addition, the exposed surface may be coat | covered with plating layers, such as a gold plating layer, in the part formed with metal materials, such as the connection pad 2, the wiring conductor, the lead terminal 4, and the metal layer 6. FIG. The plating layer can be provided on the exposed surface of the metal portion by a method such as electroplating or electroless plating.

  In the example shown in FIGS. 1 and 2, the end 4a of the lead terminal 4 has a quadrangular shape when viewed from above. A recess 5 is provided in a portion of the end 4a that overlaps two opposite sides.

The end 4a in this example is rectangular, and the short side thereof is arranged along the outer periphery of the upper surface of the insulating substrate 1. The concave portion 5 has a rectangular shape with corners formed in an arc shape, and the dimension in the long side direction is larger than the dimension in the short side direction of the end 4 a of the lead terminal 4. Since the long side direction of the concave portion 5 is arranged along the short side direction (width direction) of the end portion 4a, the concave portion 5 overlaps two opposite sides of the end portion 4a.

  Thus, when the recessed part 5 is provided in the part which overlaps two mutually opposing sides of the edge part 4a, the effect of the reliability improvement of joining with respect to the board | substrate body of the edge part 4a of the lead terminal 4 is not biased. Easy to get.

  In the above example, the same effect can be obtained even when the recess 5 has an elliptical shape. For example, the recess 5 in the example shown in FIG. 1 and FIG. 2 can be regarded as an elliptical shape in which a part of the outer periphery is directly shaped along the long axis.

  Further, as described above, the recess 5 in the example shown in FIGS. 1 and 2 has a rectangular shape in a top view. The rectangular recess 5 is arranged so as to cross the end 4a of the lead terminal 4 in the long side direction in the width direction of the end 4a.

  That is, the electronic component mounting board 10 in which the concave portion 5 is provided in the portion overlapping the two opposite sides of the end portion 4a is realized by such a form. As a result, the electronic component mounting board 10 can easily obtain the effect of improving the reliability of the bonding of the end 4a of the lead terminal 4 to the board body without bias.

  Further, in this case, since the processing of the concave portion 5 can be performed only once, for example, the electronic component mounting board 10 in which the concave portion 5 is disposed in a portion overlapping two opposite sides of the end portion 4a. This is advantageous in terms of productivity as the electronic device 20.

  In addition, since it is easy to relatively increase the size (area of the opening) of the recess 5 in a top view, the workability of applying the metal paste to be the metal layer 6 on the inner surface thereof, and the metal paste This is advantageous in terms of improvement in thickness accuracy.

  FIG. 3 is a plan view showing a first modification of FIG. In FIG. 3, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals. In the example shown in FIG. 3, the recesses 5 are arranged separately from each other in the major axis direction of the virtual region C in an elliptical virtual region C located in the connection pad 2 in a top view.

  Also in this case, since the concave portion 5 is provided in a portion that overlaps two opposite sides of the end portion 4a, the effect of improving the bonding reliability of the end portion 4a of the lead terminal 4 to the substrate body is achieved. It is possible to obtain an effect that makes it easy to obtain

  Further, in this case, since the proportion of the recess 5 in the upper surface of the insulating substrate 1 in a top view is relatively small, it is advantageous for improving the mechanical strength of the upper surface portion of the insulating substrate 1.

  Note that the above-described example (elliptical virtual region) is also used when the virtual region is rectangular (not shown) and the concave portions 5 are arranged separately in the long side direction of the virtual region. The same effect as C) can be obtained.

FIG. 4 is a plan view showing a second modification of FIG. 4, parts similar to those in FIGS. 1 and 2 are denoted by the same reference numerals. In the example shown in FIG. 4, the recess 5 is provided to extend to the tip in the major axis direction of the virtual region C similar to the example shown in FIG. 3. Therefore, FIG. 4 can also be regarded as a modification of FIG.

  Thus, even when the recess 5 is provided to extend to the tip of the virtual region C, the same effect as in each of the above examples can be obtained. In other words, the concave portion 5 is located in the portion of the end portion 4a that overlaps the two opposing sides, so that the effect of improving the reliability of bonding of the end portion 4a of the lead terminal 4 to the substrate body can be obtained without bias. Is easy. Further, since the proportion of the recess 5 in the upper surface of the insulating substrate 1 is relatively small in the top view, it is advantageous for improving the mechanical strength of the upper surface portion of the insulating substrate 1. In addition, since the size of the concave portion 5 in a top view is secured to some extent, it is easy to form the metal layer 6 on the inner surface of the concave portion 5 (application of a metal paste by a screen printing method). Accuracy improvement is also relatively easy.

  In other words, the electronic component mounting board 10 and the electronic device 20 in the example shown in FIG. 4 have the effects in the example shown in FIG. 2 and the effects in the example shown in FIG.

  In this example as well, even when the virtual region is rectangular (not shown), the reliability of joining the lead terminals 4, the ease of forming the metal layer 6, and the insulating substrate 1 are the same as described above. An effect can be obtained with respect to the mechanical strength and the like of the upper surface portion.

FIG. 5 is a plan view showing a third modification of FIG. In FIG. 5, parts similar to those in FIGS. 1 and 2 are denoted by the same reference numerals.

  Also in the example shown in FIG. 5, they are arranged separately from each other in the major axis direction of the virtual region C in the elliptical virtual region C located in the connection pad 2 in a top view. In the example shown in FIG. 5, the recess 5 is also provided at the tip of the end 4 a of the lead terminal 4. In other words, the rectangular end 4 a of the lead terminal 4 can be joined via the metal layer 6 and the brazing material 3 at three points. Therefore, the effect of improving the reliability of joining the lead terminal 4 to the substrate body can be enhanced. Also in this example, a rectangular virtual region (not shown) may be used as in the above examples.

  As described above, the electronic device 20 according to the embodiment of the present invention includes the electronic component mounting board 10 having any one of the above configurations and the electronic component 21 mounted on the mounting portion 1a. In the electronic device 20, the other end of the lead terminal 4 is electrically and mechanically connected to a predetermined portion of the external electric circuit via a conductive connecting material such as solder. As a result, electric signals are transmitted and received between the electronic component 21 and the external electric circuit, and various processes as an electronic device are performed.

  According to such an electronic device 20, since the electronic component mounting board 10 having the above-described configuration is included, the reliability of the connection between the connection pad 2 and the lead terminal 4 is improved, the mounting to an external electric circuit, etc. High reliability.

  Regarding the electronic device 20, for example, the concave mounting portion 1a may be sealed with a sealing material (not shown) such as a lid or a sealing resin. For example, the lid is a flat plate member made of a metal material, a ceramic material, or the like, and the outer peripheral portion of the lower surface thereof is joined to the portion surrounding the mounting portion 1 a on the upper surface of the insulating substrate 1 to close the mounting portion 1 a. As a result, the electronic component 21 is hermetically sealed inside the container including the concave mounting portion 1a and the lid.

  The electronic component mounting board 10 and the electronic device 20 of the present invention are not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention.

  For example, as in the example shown in FIG. 6A, the recess 5 is provided so as to overlap one side of the rectangular end of the lead terminal 4, and the brazing material 3 is provided on the inner surface of the recess 5. A metal layer 6 to which a part of the metal layer 6 is bonded may be provided. That is, a recess 5 having a portion overlapping the end 4a of the lead terminal 4 in a top view is provided, and a metal layer 6 to which a part of the brazing material 3 is bonded is provided on the inner surface of the recess 5. It only has to be. Also in this case, the reliability of bonding of the lead terminal 4 to the connection pad 2 (substrate body) can be improved as compared with the electronic component mounting substrate and the electronic device of the prior art.

  For example, the metal layer 6 may extend to the bottom surface of the recess 5 as in the example shown in FIG. In this case, since it is easy to increase the bonding area of the brazing material 3 to the metal layer 6, it is possible to effectively improve the reliability of bonding of the lead terminals 4 to the substrate body. FIG. 6A is a plan view showing a fourth modification of FIG. 2A, and FIG. 6B is a cross-sectional view showing a modification of FIG. 2B. 6, parts similar to those in FIGS. 1 and 2 are denoted by the same reference numerals.

  Further, the entire recess 5 may be located in the end 4 a of the lead terminal 4 in a top view. That is, the entire recess 5 may be hidden by the lead terminal 4 when viewed from above. Also in this case, a pool of the brazing material 3 is formed from the lower surface of the lead terminal 4 to the metal layer 6 in the recess 5, and a meniscus can be formed in the pool of the brazing material 3. Therefore, it is possible to effectively improve the reliability of bonding between the connection pad 2 and the lead terminal 4.

  Further, the end 4a of the lead terminal 4 may have a shape other than a rectangle, for example, a square shape, a quadrangle shape (for example, a rectangular shape) whose tip is formed in an arc shape or an elliptical arc shape (not shown), or the like. Further, the end portion 4a may be a shape obtained by combining a plurality of these shapes, and may have a shape as described above, and may have a shape in which a part of the outer periphery has irregularities in a top view. Good.

DESCRIPTION OF SYMBOLS 1 ... Insulation board | substrate 1a .... Mounting part 2 ... Connection pad 3 ... Brazing material 4 ... Lead terminal 5 ... Recessed part 6 ... Metal layer
10 ... Electronic component mounting board
20 ... Electronic device
21 ... Electronic component C ... Virtual region

Claims (7)

An insulating substrate having an upper surface including an electronic component mounting portion and a lower surface opposite to the upper surface;
A connection pad provided on an outer peripheral portion of at least one of the upper surface and the lower surface of the insulating substrate;
A lead terminal having an end joined to the connection pad by a brazing material,
At least one of the upper surface and the lower surface of the insulating substrate is provided with a recess having a portion that overlaps the end portion of the lead terminal in a top view or a bottom view when the connection pad is provided. An electronic component mounting board, wherein a metal layer to which a part of the brazing material is bonded is provided on an inner surface of the electronic component. 2. The top end or the bottom end view, wherein the end portion of the lead terminal has a quadrangular shape, and the concave portion is provided in a portion that overlaps two opposite sides of the end portion. The electronic component mounting board described in 1. The concave portion has a rectangular shape or an elliptical shape in a top view or a bottom view, and is arranged so as to cross an end portion of the lead terminal in a width direction of the end portion in a long side direction or a long axis direction. The electronic component mounting board according to claim 2. The concave portions are arranged separately in a rectangular or elliptical virtual region located in the connection pad in a top view or a bottom view, in the long side direction or the long axis direction of the virtual region. The electronic component mounting board according to claim 2. 5. The electronic component mounting board according to claim 4, wherein the concave portion is provided to extend to a tip in a long side direction or a long axis direction of the virtual region. 5. The electronic component mounting substrate according to claim 3, wherein the concave portion is also provided at a tip portion of the end portion. The electronic component mounting substrate according to any one of claims 1 to 6,
An electronic device comprising: an electronic component mounted on the mounting portion.

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