Electronic element mounting substrate, electronic device, and electronic module

Abstract

This substrate for mounting electronic elements comprises a substrate body having a first element mounting region for mounting a light-receiving element as a first electronic element, and a second element mounting region for mounting a light-emitting element as a second electronic element. The first element mounting region and the second element mounting region have different heights in a cross-sectional view.

Description

[Technical Field]

[0001] The present disclosure relates to an electronic element mounting substrate, an electronic device, and an electronic module. [Background technology]

[0002] Conventionally, as shown in Patent Document 1, for example, an electronic device (referred to as an optical device in Patent Document 1) has been known in which a light receiving element as a first electronic element and a light emitting element (referred to as a light emitting element array in Patent Document 1) as a second electronic element are mounted on the upper surface of a base (referred to as a substrate in Patent Document 1) made of an electrically insulating material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-155622 Summary of the Invention

[0004] The electronic device mounting substrate according to the present disclosure includes a base body having a first device mounting region for mounting a first electronic device and a second device mounting region for mounting a second electronic device, the first device mounting region and the second device mounting region having different heights in a cross-sectional view.

[0005] The electronic device according to the present disclosure includes the electronic element mounting substrate, a first electronic element mounted in the first element mounting area, and a second electronic element mounted in the second element mounting area.

[0006] An electronic module according to the present disclosure includes the electronic device and a housing located on the top surface of a base of the electronic device. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic plan view showing an electronic device according to a first embodiment. [Figure 2]FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. [Figure 3] 1 is a schematic cross-sectional plan view showing an electronic module according to a first embodiment. [Figure 4] FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 4 is a schematic plan view showing another aspect of the electronic device according to the first embodiment. [Figure 6] FIG. 6 is a schematic cross-sectional view taken along line VI-VI in FIG. 5. [Figure 7] FIG. 4 is a schematic plan view showing another aspect of the electronic device according to the first embodiment. [Figure 8] FIG. 4 is a schematic cross-sectional view showing another aspect of the electronic device according to the first embodiment. [Figure 9] FIG. 4 is a schematic cross-sectional view showing another aspect of the electronic device according to the first embodiment. [Figure 10] FIG. 4 is a schematic plan view showing another aspect of the electronic device according to the first embodiment. [Figure 11] FIG. 11 is a schematic cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 4 is a schematic plan view showing another aspect of the electronic module according to the first embodiment. [Figure 13] FIG. 13 is a schematic cross-sectional view taken along line XIII-XIII in FIG. [Figure 14] FIG. 4 is a schematic plan view showing another aspect of the electronic module according to the first embodiment. [Figure 15] FIG. 15 is a schematic cross-sectional view taken along line XV-XV in FIG. [Figure 16] FIG. 4 is a schematic plan view showing another aspect of the electronic module according to the first embodiment. [Figure 17] FIG. 17 is a schematic cross-sectional view taken along line XVII-XVII in FIG. [Figure 18] FIG. 10 is a schematic plan view showing an electronic device according to a second embodiment. [Figure 19] FIG. 19 is a schematic cross-sectional view taken along line XIX-XIX in FIG. 18. [Figure 20] FIG. 10 is a schematic plan view showing an electronic device according to a third embodiment. [Figure 21] FIG. 21 is a schematic cross-sectional view taken along line XXI-XXI in FIG. 20. [Figure 22] FIG. 13 is a schematic cross-sectional plan view showing an electronic device according to another aspect of the fourth embodiment. [Figure 23] FIG. 23 is a schematic cross-sectional view taken along line XXIII-XXIII in FIG. 22. DETAILED DESCRIPTION OF THE INVENTION

[0008] When heat generated from a light-emitting element is transmitted to a light-receiving element, the heat can cause noise or malfunction in the light-receiving element. In other words, the heat generated from a light-emitting element can cause problems in an electronic device. Therefore, it is desirable to reduce the heat transmitted from a heat-generating electronic element to other electronic elements.

[0009] The electronic element mounting substrate of the present disclosure, and the electronic device and electronic module including the substrate, can reduce the possibility of malfunctions caused by heat generated in the electronic element.

[0010] The electronic device mounting substrate, electronic device, and electronic module according to the embodiments will be described in detail below with reference to the drawings. However, for the sake of convenience, the figures referred to below show simplified views of only the components necessary for describing the embodiments. Therefore, the electronic device mounting substrate, electronic device, and electronic module according to the embodiments may include optional components not shown in the figures. The dimensions of the components in the figures do not necessarily faithfully represent the actual dimensions of the components and the dimensional ratios of each member. For convenience, the directions of the electronic device mounting substrate, electronic device, and electronic module are defined using the Cartesian coordinate system XYZ. The positive side of the X-axis direction is the right side, the positive side of the Y-axis direction is the front side, and the positive side of the Z-axis direction is the top side. In this disclosure, the term "annular" encompasses rectangular annular shapes, circular annular shapes, and elliptical annular shapes. The term "parallel" does not require strict parallelism, as long as the two are parallel at a visually recognizable level.

[0011] [Electronic Element Mounting Substrate and Electronic Device According to First Embodiment] An electronic device mounting substrate 1 and an electronic device 100 according to a first embodiment will be described with reference to Fig. 1 to Fig. 4. Fig. 1 is a schematic plan view showing the electronic device 100 according to the first embodiment. Fig. 2 is a schematic cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a schematic cross-sectional plan view showing an electronic module 200 according to the first embodiment. Fig. 4 is a schematic cross-sectional view taken along line IV-IV in Fig. 3.

[0012] As shown in the example of FIGS. 1 to 4, an electronic device 100 according to a first embodiment includes an electronic element mounting substrate 1, a light receiving element 110 as a first electronic element mounted on the electronic element mounting substrate 1, and a light emitting element 120 as a second electronic element mounted on the electronic element mounting substrate 1. The electronic element mounting substrate 1 also includes a base 2, which has, for example, a rectangular shape in a plan view. The base 2 is made of insulating ceramics such as an aluminum oxide sintered body (alumina ceramics), an aluminum nitride sintered body, a mullite sintered body, or a glass ceramic sintered body. The longitudinal direction of the base 2 may be the left-right direction (X-axis direction), and the lateral direction of the base 2 may be the front-rear direction (Y-axis direction).

[0013] Because the base 2 is made of insulating ceramics, the base 2 has high heat dissipation properties and high rigidity. Furthermore, even when the base 2 has an irregular shape or through-holes, dust and other particles are less likely to be generated. Even when the base 2 is heated by the heat generated by the light-emitting element 120, moisture and gas are less likely to be generated. Furthermore, the difference between the thermal expansion coefficient of silicon constituting the light-receiving element 110 and the light-emitting element 120 and the thermal expansion coefficient of the insulating ceramic is smaller than the difference between the thermal expansion coefficient of the organic material and the thermal expansion coefficient of the insulating ceramic. Therefore, compared to a base 2 made of organic materials, a base 2 made of insulating ceramics can reduce stress on electronic elements even when the light-emitting element 120 generates heat.

[0014] The substrate 2 may have a base portion 21, and the shape of the base portion 21 in a plan view is, for example, rectangular. The base portion 21 has an upper surface 21u and a lower surface 21d. The base portion 21 may be composed of three stacked insulating layers 21a. The base portion 21 may be composed of a plurality of insulating layers 21a other than three stacked insulating layers 21a, or may be composed of a single insulating layer 21a.

[0015] The base 2 may have a first pedestal 22 located to the right of the upper surface 21u of the base 21. The first pedestal 22 is integral with the base 21 and has a first upper surface 22u. The first pedestal 22 may be composed of two stacked insulating layers 22a. The multiple insulating layers 22a may be stepped in cross-sectional view. The first pedestal 22 may be composed of multiple insulating layers 22a other than two stacked insulating layers 22a, or may be composed of a single insulating layer 22a.

[0016] A first element mounting region F1 for mounting a light receiving element 110 as a first electronic element may be located on the upper surface of the upper insulating layer 22a, which is the first upper surface 22u of the first pedestal 22. In other words, the first upper surface 22u of the first pedestal 22 includes the first element mounting region F1. In further other words, the base 2 may have the first element mounting region F1 on the first upper surface 22u of the first pedestal 22. The first element mounting region F1 may be a region that overlaps with the light receiving element 110 in a plan view. The first element mounting region F1 may be a region surrounded by imaginary lines connecting alignment marks used when mounting the light receiving element 110. The first element mounting region F1 may be a region where a metallization layer for mounting the light receiving element 110 is located.

[0017] A second element mounting region F2 for mounting a light emitting element 120 as a second electronic element may be located to the left of the first seat 22 on the upper surface 21u of the base 21. In other words, the upper surface 21u of the base 21 may include the second element mounting region F2. In further other words, the substrate 2 may have the second element mounting region F2 to the left of the first seat 22 on the upper surface of the base 21. The second element mounting region F2 may be a region that overlaps with the light emitting element 120 in a plan view. The second element mounting region F2 may be a region surrounded by imaginary lines connecting alignment marks used when mounting the light emitting element 120. The second element mounting region F2 may be a region where a metallized layer for mounting the light emitting element 120 is located.

[0018] The first element mounting area F1 and the second element mounting area F2 are parallel in cross-sectional view but have different heights. The parallel configuration of the first element mounting area F1 and the second element mounting area F2 simplifies the mounting process for the light receiving element 110 and the light emitting element 120 and enables the light receiving element 110 and the light emitting element 120 to be mounted using the same manufacturing equipment. Furthermore, the parallel mounting surfaces reduce the possibility of the light receiving element 110 and the light emitting element 120 becoming dislodged or misaligned from the upper surface of the base 2, especially when the electronic device 100 is used for a long period of time. Furthermore, heat generated by the electronic elements is more easily transferred uniformly from the upper surface of the base 2 directly downward. Furthermore, the difference in the amount of heat propagation (heat distribution) between the first element mounting area F1 and the second element mounting area F2 is reduced, facilitating temperature control. Furthermore, light emitted from the light emitting element 120 is reflected and directly received by the light receiving element 110.

[0019] In a cross-sectional view, the first element mounting area F1 may be higher than the second element mounting area F2 by the thickness of the first seat 22. The arrangement direction in which the first element mounting area F1 and the second element mounting area F2 are aligned may be the longitudinal direction (X-axis direction) of the base 2. The direction perpendicular to the arrangement direction of the first element mounting area F1 and the second element mounting area F2 may be the lateral direction (Y-axis direction) of the base 2. The arrangement direction is not limited to the X-axis direction of the base 2 depending on the shapes of the base 2, the first element mounting area F1, and the second element mounting area F2 in a planar view. The arrangement direction may be, for example, a direction along a line connecting the center of the first element mounting area F1 and the center of the second element mounting area F2.

[0020] A plurality of first connection pads 3 may be provided outside the first element mounting region F1 on the first upper surface 22u of the first pedestal 22. Each of the plurality of first connection pads 3 may be connected to a corresponding electrode of the light-receiving element 110, which serves as the first electronic element, by a wire W. In other words, each of the plurality of first connection pads 3 may be connected to a corresponding electrode of the light-receiving element 110 by wire bonding. Alternatively, each of the plurality of first connection pads 3 may be connected to a corresponding electrode of the light-receiving element 110 by flip-chip bonding.

[0021] A plurality of first external electrodes 4 may be provided on the lower surface 21d or side surfaces of the base 21. Each of the plurality of first external electrodes 4 may be electrically connected to a corresponding first electrode of an external substrate. Furthermore, a plurality of first wiring conductors 5 may be provided inside the base 2, and the plurality of first wiring conductors 5 may electrically connect each of the plurality of first connection pads 3 to a corresponding first external electrode 4. Each of the plurality of first wiring conductors 5 may include a through conductor that penetrates the insulating layer 21a, a through conductor that penetrates the insulating layer 22a, and internal wiring.

[0022] Two second connection pads 6 may be provided on the upper surface 21u of the base 21. One of the second connection pads 6 may be located in an area including the second element mounting area F2 on the upper surface 21u of the base 21, and may function as a mounting pad for mounting a light-emitting element 120 serving as a second electronic element. The other second connection pad 6 may be located outside the second element mounting area F2 on the upper surface 21u of the base 21. Each of the two second connection pads 6 may be connected to a corresponding electrode of the light-emitting element 120 serving as the second electronic element by a wire W. In other words, each of the two second connection pads 6 may be connected to a corresponding electrode of the light-emitting element 120 by wire bonding. Each of the two second connection pads 6 may be connected to a corresponding electrode of the light-emitting element 120 by flip-chip bonding.

[0023] Two second external electrodes 7 may be provided on the lower surface 21d or a side surface of the base 21. Each of the two second external electrodes 7 may be electrically connected to a corresponding second electrode of an external substrate. Furthermore, two second wiring conductors 8 may be provided inside the base 2, and the two second wiring conductors 8 may electrically connect each of the two second connection pads 6 to the corresponding second external electrode 7. Each of the multiple second wiring conductors 8 may include a through conductor that penetrates the insulating layer 21a and an internal wiring.

[0024] The first connection pad 3, the first external electrode 4, the first wiring conductor 5, the second connection pad 6, the second external electrode 7, and the second wiring conductor 8 are made of a metal powder metallization containing, for example, tungsten (W), molybdenum (Mo), manganese (Mn), silver (Ag), or copper (Cu) as components.

[0025] As shown in the example of FIGS. 1 and 2, when the base 2 is made of, for example, an aluminum oxide sintered body, the base 2 is produced as follows. A slurry is produced by adding an appropriate organic binder, solvent, etc. to raw material powders such as aluminum oxide and silicon oxide and mixing them. This slurry is formed into a sheet by a doctor blade method, a calendar roll method, etc., to produce ceramic green sheets for the insulating layers 21a, 22a. A plurality of ceramic green sheets for the insulating layers 21a, 22a are then stacked to produce a laminate for the base 2. The laminate for the base 2 is fired at a high temperature (approximately 1300 to 1600°C) to produce the base 2.

[0026] When the first connection pads 3, first external electrodes 4, first wiring conductors 5, second connection pads 6, second external electrodes 7, and second wiring conductors 8 are, for example, metallized layers of tungsten, they can be formed as follows. The internal wiring of the first connection pads 3, first external electrodes 4, and first wiring conductors 5, and the internal wiring of the second connection pads 6, second external electrodes 7, and second wiring conductors 8 are formed as follows. This internal wiring is formed by printing a metal paste, prepared by mixing tungsten powder with an organic solvent and an organic binder, at predetermined positions on the ceramic green sheets for the insulating layers 21a and 22a by a method such as screen printing, and then firing the laminate for the base 2. The through conductors of the first wiring conductors 5 and the second wiring conductors 8 are formed by providing through conductor holes at predetermined positions on the ceramic green sheets for the insulating layers 21a and 22a and filling the through conductor holes with the metal paste.

[0027] The surfaces of the first connection pads 3, the first external electrodes 4, the first wiring conductors 5, the second connection pads 6, the second external electrodes 7, and the second wiring conductors 8 that are exposed to the outside may be coated with a metal plating layer such as a nickel plating layer or a gold plating layer by plating. The plating method may be, for example, electrolytic plating or electroless plating. This effectively reduces corrosion of the first wiring conductors 5 and the second wiring conductors 8. The metal plating layer is not limited to a nickel plating layer or a gold plating layer, but may be other metal plating layers such as a nickel plating layer, a palladium plating layer, or a gold plating layer.

[0028] As shown in FIGS. 1 and 2 , in the configuration of the electronic device mounting substrate 1 according to the first embodiment, the first element mounting region F1 and the second element mounting region F2 are located at different heights in a cross-sectional view. In particular, when the first upper surface 22u of the first pedestal 22 includes the first element mounting region F1 and the upper surface of the base 21 includes the second element mounting region F2, the first element mounting region F1 and the second element mounting region F2 are located at different heights in a cross-sectional view by the height of the first pedestal 22. This allows the distance between the first element mounting region F1 and the second element mounting region F2 to be increased. Furthermore, since the distance from the second element mounting region F2, which serves as a heat-generating portion, to the bottom surface of the base 2 that contacts the outside is shorter than the distance from the first element mounting region F1 to the bottom surface, heat from the heat-generating portion is more likely to propagate from the bottom surface of the base 2 to the outside. Therefore, heat generated by the light-emitting element 120 serving as the second electronic element is less likely to propagate to the light-receiving element 110 serving as the first electronic element. This reduces the possibility of malfunction of the light receiving element 110 due to heat generated by the light emitting element 120. Furthermore, by increasing the height of the first element mounting area F1 in a cross-sectional view and ensuring the distance between the first element mounting area F1 and the second element mounting area F2, the distance between the first element mounting area F1 and the second element mounting area F2 in a plan view can be shortened. In other words, the electronic device 100 can be made smaller.

[0029] When the first seat 22 is configured with a plurality of stacked insulating layers 22a, the plurality of insulating layers 22a facilitates creating a large difference in height between the first element mounting area F1 and the second element mounting area F2 in a cross-sectional view. This also facilitates adjusting the height of the first seat 22. Therefore, heat generated in the light-emitting element 120 is less likely to propagate toward the light-receiving element 110. This further reduces the possibility of malfunction of the light-receiving element 110 due to heat generated in the light-emitting element 120.

[0030] When the insulating layers 22a are stepped in cross section, it is possible to adjust the installation positions of the first connection pads 3. Furthermore, in addition to the upper surface of the uppermost insulating layer 22a, which is the first upper surface 22u of the first pedestal 22, it is possible to install electronic components such as capacitors on the upper surfaces of the lower insulating layers 22a. Furthermore, since the first connection pads 3 and electronic components such as capacitors can be installed in close proximity to each other, the electrical characteristics of the electronic device 100 are improved.

[0031] 1 and 2, an electronic device 100 includes an electronic element mounting substrate 1, a light receiving element 110 as a first electronic element mounted in a first element mounting area F1 of a base 2, and a light emitting element 120 as a second electronic element mounted in a second element mounting area F2 of the base 2. A first electronic element other than the light receiving element 110 may be mounted in the first element mounting area F1 of the base 2. A second electronic element other than the light emitting element 120 may be mounted in the second element mounting area F2 of the base 2.

[0032] The light receiving element 110 may be, for example, a photodiode, and may be bonded to the first element mounting region F1 of the base 2 with an adhesive. Each of the plurality of electrodes of the light receiving element 110 may be connected to a corresponding first connection pad 3 by wire bonding or flip-chip bonding. The light emitting element 120 may be, for example, an LED (Light Emitting Diode) or a VCSEL (Vertical Cavity Surface Emitting Laser) type laser diode, and may be bonded to the second element mounting region F2 of the base 2 by one of the second connection pads 6. Each of the two electrodes of the light emitting element 120 may be connected to a corresponding second connection pad 6 by wire bonding or flip-chip bonding.

[0033] As shown in the example of Figures 1 and 2, the electronic device 100 includes an electronic element mounting substrate 1, which further reduces the possibility of problems such as noise or malfunction of the light receiving element 110 caused by heat generated in the light emitting element 120 propagating to the light receiving element 110.

[0034] As shown in the example of FIGS. 3 and 4 , the electronic module 200 according to the first embodiment includes the electronic device 100 and a housing 210 located on the upper surface 21u of the base portion 21 of the base 2 of the electronic device 100. The housing 210 is made of, for example, a metal such as aluminum (Al) or a resin such as PBT (polybutylene terephthalate). The housing 210 may be joined to the upper surface 21u of the base portion 21 of the base 2 with a bonding material such as a brazing material or an adhesive. The housing 210 may cover an upper portion of the first element mounting region F1 of the base 2. Instead of covering an upper portion of the first element mounting region F1 of the base 2, the housing 210 may cover an upper portion of the second element mounting region F2 of the base 2.

[0035] Housing 210 may have a holding hole 220 in its upper portion, and holding hole 220 penetrates the upper portion of housing 210. Lens 230 may be provided in holding hole 220 of housing 210, and lens 230 may have the function of focusing external light incident from outside onto the light receiving surface of light receiving element 110. An IR cut filter that blocks infrared rays may be provided on the light output side of lens 230.

[0036] As shown in the examples of Figures 3 and 4, the electronic module 200 includes the electronic device 100, which can further reduce the possibility of problems such as noise or malfunction of the light-receiving element 110 caused by heat generated in the light-emitting element 120 being transmitted to the light-receiving element 110.

[0037] [Electronic Element Mounting Board and Electronic Device According to Other Aspects of the First Embodiment] The configurations of an electronic device mounting substrate 1 and an electronic device 100 according to another aspect of the first embodiment will be described with reference to FIGS. 5 to 11. FIG. 5 is a schematic plan view showing another aspect of the electronic device 100 according to the first embodiment. FIG. 6 is a schematic cross-sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a schematic plan view showing another aspect of the electronic device 100 according to the first embodiment. FIG. 8 is a schematic cross-sectional view showing another aspect of the electronic device 100 according to the first embodiment. FIG. 9 is a schematic cross-sectional view showing another aspect of the electronic device 100 according to the first embodiment. FIG. 10 is a schematic plan view showing another aspect of the electronic device 100 according to the first embodiment. FIG. 11 is a schematic cross-sectional view taken along line XI-XI in FIG. 10.

[0038] 5 and 6, the side surfaces of the insulating layers 22a may coincide in a planar view. In this case, the base 2 can be made smaller and lighter, in other words, the electronic device mounting substrate 1 can be made smaller and lighter. In other words, in the present disclosure, the electronic device mounting substrate 1 can be made smaller by lengthening the propagation path in the thickness direction rather than lengthening the propagation path in the planar direction between the light emitting element 120 and the light receiving element 110 to reduce heat propagation. Furthermore, having the side surfaces of the insulating layers 22a coincide in a planar view is advantageous for further miniaturizing the electronic device mounting substrate 1.

[0039] 7, the two first side surfaces 22s of the first seat 22 parallel to the left-right direction (X-axis direction), which is the arrangement direction of the first element mounting area F1 and the second element mounting area F2, may coincide with the two third side surfaces 21s of the base 21 parallel to the left-right direction in a plan view. In this case, the first upper surface 22u of the first seat 22 expands in the front-rear direction (Y-axis direction). This makes it possible to ensure space for installing the housing 210 on the first seat 22. Furthermore, electronic components such as a capacitor can be installed at the same height as the light receiving element 110 serving as the first electronic element, thereby improving the electrical characteristics of the electronic device 100.

[0040] 8, the electronic device mounting board 1 may include a plurality of thermal vias 9 that penetrate along the thickness direction of the base 2 at positions that overlap the light emitting element 120 in a top view. Each of the plurality of thermal vias 9 may be connected to the second device mounting region F2.

[0041] The thermal vias 9 are made of metal powder metallization containing, for example, tungsten (W), molybdenum (Mo), manganese (Mn), silver (Ag), copper (Cu), etc. The thermal vias 9 are formed by providing holes for the thermal vias at predetermined positions in the ceramic green sheets for the insulating layers 21a and 22a and filling the holes for the thermal vias with metal paste.

[0042] When the electronic device mounting substrate 1 has a plurality of thermal vias 9, the heat generated in the light emitting element 120 propagates to the underside of the base 2. This further reduces the possibility of malfunction of the light receiving element 110 due to the heat generated in the light emitting element 120.

[0043] 9, the electronic device mounting board 1 may include a heat sink 10 that is located on the lower surface 21d of the base 21, which is the lower surface of the substrate 2, and that dissipates heat generated from the light emitting element 120. The heat sink 10 may be bonded to the lower surface 21d of the base 21 with a bonding material such as a resin adhesive. The heat sink 10 may be made of a metal with high thermal conductivity, such as aluminum.

[0044] When the electronic device mounting substrate 1 is provided with the heat sink 10, the heat generated in the light emitting element 120 is dissipated by the heat sink 10. This further reduces the possibility of malfunction of the light receiving element 110 due to the heat generated in the light emitting element 120.

[0045] 10 and 11, a groove 21g extending in the short-side direction (Y-axis direction) of the base 2 may be located between the first element mounting area F1 and the second element mounting area F2 on the underside 21d of the base 21. A heat shield 11 having a lower thermal conductivity than the base 2 may be located in the groove 21g of the base 21. In other words, a heat shield 11 extending in the short-side direction of the base 2 may be located between the first element mounting area F1 and the second element mounting area F2 on the base 2. The heat shield 11 is made of, for example, a thermosetting resin or a thermoplastic resin.

[0046] The grooves 21g of the base 21 are formed by subjecting the ceramic green sheets for the insulating layers to an appropriate punching process or the like before firing the laminate for the base 2.

[0047] When the electronic device mounting substrate 1 includes the heat shielding portion 11, the heat generated in the light emitting element 120 is less likely to propagate toward the light receiving element 110. This further reduces the possibility of malfunction of the light receiving element 110 due to the heat generated in the light emitting element 120.

[0048] [Electronic module according to another aspect of the first embodiment] An electronic module 200 according to a modified example of the first embodiment will be described with reference to FIGS. 12 to 17. FIG. 12 is a schematic plan view showing another aspect of the electronic module 200 according to the first embodiment. FIG. 13 is a schematic cross-sectional view taken along line XIII-XIII in FIG. 12. FIG. 14 is a schematic plan view showing another aspect of the electronic module 200 according to the first embodiment. FIG. 15 is a schematic cross-sectional view taken along line XV-XV in FIG. 14. FIG. 16 is a schematic plan view showing another aspect of the electronic module 200 according to the first embodiment. FIG. 17 is a schematic cross-sectional view taken along line XVII-XVII in FIG. 16.

[0049] 12 and 13, a part of the portion of the housing 210 that is joined to the base 2 may be located on the upper surface of the insulating layer 22a on the lower side of the first seat 22 of the base 2. The shape of the housing 210 in a front view may be an inverted U-shape. The housing 210 may be joined to the upper surface of the insulating layer 22a on the lower side of the first seat 22 of the base 2 with a joining material such as a brazing material or an adhesive. Furthermore, the shape of the housing 210 in a side view may be an inverted U-shape, as in the example shown in FIGS. 14 and 15.

[0050] 16 and 17 , the electronic module 200 may include a housing 210 as a first housing located on the upper surface 21u of the base portion 21 of the base 2, as well as a second housing 240 located on the upper surface 21u of the base portion 21 of the base 2. The second housing 240 may be made of, for example, a metal such as aluminum (Al) or a resin such as PBT (polybutylene terephthalate). The second housing 240 may be joined to the upper surface 21u of the base portion 21 of the base 2 with a joining material such as a brazing material or an adhesive. The second housing 240 may cover an area above the first element mounting region F1 of the base 2, an area above the second element mounting region F2 of the base 2, and an area above the first housing 210.

[0051] Second housing 240 may have two holding holes 250, 260 in its upper portion, and each of the two holding holes 250, 260 penetrates the upper portion of second housing 240. Lenses 270, 280 may be provided in each of the two holding holes 250, 260 of second housing 240. Lens 270 may have a function of converging, diverging, or collimating the light emitted from light-emitting element 120. Lens 270 may have a function of converging external light incident from the outside. Instead of lenses 270, 280, each of the two holding holes 250, 260 of second housing 240 may be provided with a light-transmitting member such as a glass plate.

[0052] [Electronic Element Mounting Substrate and Electronic Device According to Second Embodiment] An electronic element mounting board 1A and an electronic device 100A according to a second embodiment will be described with reference to Fig. 18 and Fig. 19. Fig. 18 is a schematic plan view showing the electronic device 100A according to the second embodiment. Fig. 19 is a schematic cross-sectional view taken along line XIX-XIX in Fig. 18.

[0053] As shown in the example of FIGS. 18 and 19, an electronic device 100A includes an electronic element mounting board 1A, a light receiving element 110 as a first electronic element mounted on the electronic element mounting board 1A, and a light emitting element 120 as a second electronic element mounted on the electronic element mounting board 1A. The electronic element mounting board 1A according to the second embodiment has the same configuration as the electronic element mounting board 1 according to the first embodiment, with some exceptions. Of the configuration of the electronic element mounting board 1A according to the second embodiment, differences from the configuration of the electronic element mounting board 1 according to the first embodiment will be mainly described. For ease of description, components having the same functions as those described in the first embodiment will be denoted by the same reference numerals.

[0054] Instead of having the first pedestal 22, the base 2 may have a second pedestal 23 located on the left side of the upper surface of the base 21. The second pedestal 23 is integral with the base 21 and has a second upper surface 23u. The second pedestal 23 may be composed of two stacked insulating layers 23a. The multiple insulating layers 23a may be stepped in cross-sectional view. The second pedestal 23 may be composed of multiple insulating layers 23a other than two stacked insulating layers 23a, or may be composed of a single insulating layer 23a.

[0055] A first element mounting region F1 for mounting a light receiving element 110 as a first electronic element may be located in a right portion of the upper surface 21u of the base 21. In other words, the base 2 may have the first element mounting region F1 in a right portion of the upper surface 21u of the base 21. Furthermore, a second element mounting region F2 for mounting a light emitting element 120 as a second electronic element may be located on the upper surface of the upper insulating layer 23a, which is the second upper surface 23u of the second pedestal 23. In other words, the second upper surface 23u of the second pedestal 23 includes the second element mounting region F2. In further other words, the base 2 may have the second element mounting region F2 on the second upper surface 23u of the second pedestal 23. Furthermore, the first element mounting region F1 and the second element mounting region F2 are parallel to each other in a cross-sectional view but have different heights. The second element mounting area F2 may be higher than the first element mounting area F1 by the thickness of the second seat 23 in a cross-sectional view.

[0056] The base 2 having the second pedestal 23 is manufactured by the same method as the base 2 having the first pedestal 22 .

[0057] As shown in the example of FIGS. 18 and 19 , in the configuration of the electronic device mounting board 1A according to the second embodiment, the first device mounting region F1 and the second device mounting region F2 are located at different heights in a cross-sectional view. This allows for a larger distance between the first device mounting region F1 and the second device mounting region F2. Furthermore, the distance from the first device mounting region F1 to the bottom surface of the base 2, which is in contact with the outside, is shorter than the distance from the second device mounting region F2 to the bottom surface. When heat propagates from the light-emitting element 120, at least a portion of the heat is dissipated to the outside, which is in contact with the base 2, thereby reducing the thermal impact on the light-receiving element 110. Therefore, heat generated in the light-emitting element 120 (the second electronic element) is less likely to propagate to the light-receiving element 110 (the first electronic element). This reduces the possibility of malfunction of the light-receiving element 110 due to heat generated in the light-emitting element 120. In addition, by increasing the distance between the first element mounting area F1 and the second element mounting area F2 in a cross-sectional view and providing a distance between the first element mounting area F1 and the second element mounting area F2, it is possible to reduce the size of the electronic device 100A.

[0058] When the second seat 23 is configured with multiple stacked insulating layers 23a, the multiple insulating layers 23a make it easy to create a large difference in height between the first element mounting area F1 and the second element mounting area F2 in a cross-sectional view. This also makes it easier to adjust the height of the second seat 23. Therefore, heat generated in the light-emitting element 120 is less likely to propagate toward the light-receiving element 110. This further reduces the possibility of malfunctions in the light-receiving element 110 due to heat generated in the light-emitting element 120.

[0059] When the insulating layers 23a are stepped in cross section, the installation positions of the second connection pads 6 can be adjusted. In this case, electronic components such as capacitors can be installed on the upper surfaces of the lower insulating layers 23a in addition to the upper surface of the uppermost insulating layer 23a. Furthermore, since the second connection pads 6 and the electronic components such as capacitors can be installed in close proximity to each other, the electrical characteristics of the electronic device 100A are improved.

[0060] [Electronic element mounting substrate according to another aspect of the second embodiment] The side surfaces of the insulating layers 23a may coincide with each other in a plan view. In this case, the base 2 can be made smaller and lighter, in other words, the electronic device mounting board 1A can be made smaller and lighter. In other words, in the present disclosure, the electronic device mounting board 1A can be made smaller by lengthening the propagation path in the thickness direction rather than lengthening the propagation path in the planar direction between the light emitting element 120 and the light receiving element 110 to reduce heat propagation. Furthermore, having the side surfaces of the insulating layers 23a coincide with each other in a plan view is advantageous for further miniaturizing the electronic device mounting board 1A.

[0061] The two second side surfaces of the second seat 23, which are parallel to the left-right direction (X-axis direction), which is the arrangement direction of the first element mounting area F1 and the second element mounting area F2, may coincide with the two third side surfaces 21s of the base 21, which are parallel to the left-right direction, in a plan view. In this case, the second upper surface 23u of the second seat 23 expands in the front-rear direction (Y-axis direction). This makes it possible to ensure space for installing the housing 210 on the second upper surface 23u of the second seat 23. Furthermore, electronic components such as a capacitor can be installed at the same height as the light-emitting element 120 serving as the second electronic element, thereby improving the electrical characteristics of the electronic device 100A.

[0062] The base 2 may have a first seat 22 located on the right side of the upper surface 21u of the base 21. A first element mounting region F1 may be located on the upper surface of the upper insulating layer 22a, which is the first upper surface 22u of the first seat 22.

[0063] [Electronic Element Mounting Substrate and Electronic Device According to Third Embodiment] An electronic element mounting substrate 1B and an electronic device 100B according to a third embodiment will be described with reference to Fig. 20 and Fig. 21. Fig. 20 is a schematic plan view showing the electronic device 100B according to the third embodiment. Fig. 21 is a schematic cross-sectional view taken along line XXI-XXI in Fig. 20, showing only the cut surface of the electronic device 100B according to the third embodiment.

[0064] As shown in the example of FIGS. 20 and 21 , an electronic device 100B includes an electronic element mounting board 1B, a light receiving element 110 as a first electronic element mounted on the electronic element mounting board 1B, and a light emitting element 120 as a second electronic element mounted on the electronic element mounting board 1B. The electronic element mounting board 1B according to the third embodiment has the same configuration as the electronic element mounting board 1 according to the first embodiment, with some exceptions. The following mainly describes the differences between the configuration of the electronic element mounting board 1B according to the third embodiment and the configuration of the electronic element mounting board 11B according to the first embodiment. For ease of explanation, the same reference numerals are used to designate components that have the same functions as the components described in the first embodiment.

[0065] The base 2 may have a stepped first accommodating hole 24 for accommodating the light receiving element 110. The first accommodating hole 24 may penetrate the base 2 in the thickness direction from the upper surface of the first seat 22 to the lower surface of the base 21. The first accommodating hole 24 may have a rectangular shape in a plan view. Furthermore, a first element mounting region F1 for mounting the light receiving element 110 as the first electronic element may be located on a rectangular annular stepped surface 24p of the first accommodating hole 24. In other words, the base 2 may have the first element mounting region F1 on the stepped surface 24p of the first accommodating hole 24.

[0066] The first element mounting area F1 may be an area that overlaps the step surface 24p of the first accommodating hole 24 in a plan view. The first element mounting area F1 may be an area surrounded by imaginary lines connecting alignment marks used when mounting the light receiving element 110. The first element mounting area F1 may be an area where a metallized layer for mounting the light receiving element 110 is located. The first element mounting area F1 and the second element mounting area F2 are parallel to each other but have different heights in a cross-sectional view.

[0067] A plurality of first connection pads 3 may be provided on the stepped surface 24p of the first accommodating hole 24. Each of the plurality of first connection pads 3 may be connected to a corresponding electrode of the light-emitting element 120 as the second electronic element by a bump B. In other words, each of the plurality of first connection pads 3 may be connected to a corresponding electrode of the light-receiving element 110 by flip-chip bonding. Each of the plurality of first connection pads 3 may be connected to a corresponding electrode of the light-receiving element 110 by wire bonding. The stepped surface 24p is part of the surface of the insulating layer 22a located at the top of the first accommodating hole 24.

[0068] The first receiving hole 24 of the base 2 is formed by subjecting the ceramic green sheets for the insulating layers 21a and 22a to an appropriate punching process or the like before firing the laminate for the base 2.

[0069] As shown in the examples of FIGS. 20 and 21 , in the configuration of the electronic device mounting substrate 1B according to the third embodiment, the first element mounting region F1 and the second element mounting region F2 are located at different heights in a cross-sectional view. This allows for a larger distance between the first element mounting region F1 and the second element mounting region F2. Furthermore, the distance from the second element mounting region F2, which serves as a heat-generating portion, to the underside of the base 2 that contacts the outside is shorter than the distance from the first element mounting region F1 to the underside. This facilitates the transfer of heat from the heat-generating portion from the underside of the base 2 to the outside. This reduces the likelihood of heat generated by the light-emitting element 120 as the second electronic element propagating to the light-receiving element 110 as the first electronic element.

[0070] When the rectangular annular step surface 24p of the first accommodating hole 24 is located in the first element mounting region F1, the contact area between the light receiving element 110 and the base 21 via the bump B becomes smaller, making it more difficult for heat generated in the light emitting element 120 to propagate toward the light receiving element 110. This further reduces the possibility of malfunction of the light receiving element 110 due to heat generated in the light emitting element 120.

[0071] [Electronic Element Mounting Substrate and Electronic Device According to Fourth Embodiment] An electronic element mounting board 1C and an electronic device 100C according to the fourth embodiment will be described with reference to Fig. 22 and Fig. 23. Fig. 22 is a schematic cross-sectional plan view showing an electronic device 100C according to another aspect of the fourth embodiment. Fig. 23 is a schematic cross-sectional view taken along line XXIII-XXIII in Fig. 22, showing only the cut surface of the electronic device 100C according to another aspect of the fourth embodiment.

[0072] As shown in the example of FIGS. 22 and 23, an electronic device 100C includes an electronic element mounting board 1C, a light receiving element 110 as a first electronic element mounted on the electronic element mounting board 1C, and a light emitting element 120 as a second electronic element mounted on the electronic element mounting board 1C. The electronic element mounting board 1C according to the fourth embodiment has the same configuration as the electronic element mounting board 1 according to the first embodiment, with some exceptions. The following mainly describes the differences between the configuration of the electronic element mounting board 1C according to the fourth embodiment and the configuration of the electronic element mounting board 1 according to the first embodiment. For ease of explanation, the same reference numerals are used to refer to components that have the same functions as the components described in the first embodiment.

[0073] The base 2 may have a stepped second accommodating hole 25 for accommodating the light emitting element 120. The second accommodating hole 25 may penetrate the base 2 in the thickness direction from the upper surface of the base 21 to the lower surface of the base 21. The second accommodating hole 25 may have a rectangular shape in a plan view. Furthermore, a second element mounting region F2 for mounting the light emitting element 120 as a second electronic element may be located on a rectangular annular stepped surface 25p of the second accommodating hole 25. In other words, the base 2 may have the second element mounting region F2 on the stepped surface 25p of the second accommodating hole 25.

[0074] The second element mounting area F2 may be an area that overlaps with the step surface 25p of the second accommodating hole 25 in a plan view. The second element mounting area F2 may be an area surrounded by imaginary lines connecting alignment marks used when mounting the light emitting element 120. The second element mounting area F2 may be an area where a metallized layer for mounting the light emitting element 120 is located. The first element mounting area F1 and the second element mounting area F2 are parallel to each other but have different heights in a cross-sectional view.

[0075] A plurality of second connection pads 6 may be provided on the stepped surface 25p of the second accommodating hole 25. Each of the plurality of second connection pads 6 may be connected to a corresponding electrode of the light emitting element 120 by a bump B. In other words, each of the plurality of second connection pads 6 may be connected to a corresponding electrode of the light emitting element 120 by a flip-chip bonding method. Each of the plurality of second connection pads 6 may be connected to a corresponding electrode of the light emitting element 120 by a wire bonding method. The stepped surface 25p is part of the surface of the insulating layer 21a located at the top of the second accommodating hole 25.

[0076] The second receiving hole 25 of the base 2 is formed by subjecting the ceramic green sheet for the insulating layer 21a to an appropriate punching process or the like before firing the laminate for the base 2.

[0077] 22 and 23, in the configuration of the electronic element mounting board 1C according to the fourth embodiment, the first element mounting region F1 and the second element mounting region F2 are located at different heights in a cross-sectional view. This allows the distance between the first element mounting region F1 and the second element mounting region F2 to be increased. This makes it difficult for heat generated in the light-emitting element 120 serving as the second electronic element to propagate to the light-receiving element 110 serving as the first electronic element. This reduces the possibility of malfunction of the light-receiving element 110 due to heat generated in the light-emitting element 120.

[0078] When the rectangular annular step surface 25p of the second accommodating hole 25 is located in the second element mounting region F2, the contact area between the light emitting element 120 and the base 21 via the bump B is reduced, making it more difficult for heat generated in the light emitting element 120 to propagate toward the light receiving element 110. This further reduces the possibility of malfunction of the light receiving element 110 due to heat generated in the light emitting element 120. Furthermore, fitting the light emitting element 120 within the second accommodating hole 25 is advantageous in terms of reducing the height of the electronic device 100C.

[0079] The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art would easily be able to make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure. [Explanation of symbols]

[0080] 1. Electronic element mounting substrate (electronic element mounting substrate according to the first embodiment) 2 Base 21 Base 21a Insulating layer 21u top 21d Bottom surface 21s 3rd aspect 22 First Pedestal 22u 1st top surface 22s 1st side 3 First connection pad 4 1st external electrode 5 First wiring conductor 6 Second connection pad 7 Second external electrode 8 Second wiring conductor 9 Thermal vias 10 Heatsink 11 Heat shield 100 Electronic device (electronic device according to the first embodiment) 110 Photodetector (first electronic element) 120 Light-emitting element (second electronic element) 200 Electronic module (electronic module according to the first embodiment) 210 cabinet (first cabinet) 220 retaining hole 230 Lens 240 Second cabinet 250 retaining holes 260 retaining hole 270 Lens 280 Lens F1 First element mounting area F2 Second element mounting area 1A Electronic element mounting substrate (electronic element mounting substrate according to the second embodiment) 23 Second Pedestal 23a Insulating layer 23u 2nd top surface 1B Electronic element mounting substrate (electronic element mounting substrate according to the third embodiment) 24 First Receiving Hole 24p step surface 1C Electronic element mounting substrate (electronic element mounting substrate according to the fourth embodiment) 25 Second Receiving Hole 25p step surface

Claims

1. An upper surface, a lower surface located opposite the upper surface; a first receiving hole located on the lower surface; a first step portion located within the first receiving hole; a first element mounting area located in the first step portion and for mounting a light receiving element; a second element mounting region for mounting a laser diode, and a base body made of insulating ceramics; the first receiving hole penetrates the base, The substrate for mounting electronic elements, wherein the first element mounting region is located closer to the lower surface than the second element mounting region in a thickness direction of the base body.

2. The substrate is Further, a first base is provided on the upper surface, The electronic device mounting substrate according to claim 1 , wherein the first accommodating hole penetrates through the first seat.

3. The electronic device mounting substrate according to claim 2 , wherein the first base is made up of a plurality of laminated insulating layers.

4. The electronic device mounting board according to claim 3 , wherein the side surfaces of the plurality of insulating layers are aligned in a plan view.

5. The electronic device mounting substrate according to claim 3 , wherein the plurality of insulating layers are stepped in cross section.

6. the base has a rectangular shape in a plan view, and the first base has a rectangular shape in a plan view, 3. The electronic element mounting substrate according to claim 2, wherein two first side surfaces of the first base parallel to the arrangement direction of the first element mounting area and the second element mounting area coincide with two third side surfaces constituting the outer shape of the base parallel to the arrangement direction in a planar view.

7. The substrate is The electronic device mounting board according to claim 1 , further comprising a second pedestal located on the top surface and having a second top surface that includes the second device mounting area.

8. The substrate is a second receiving hole located on the lower surface; a second step portion located in the second accommodating hole and on which the second element mounting region is located, The electronic device mounting substrate according to claim 1 , wherein the second accommodating hole penetrates the base body.

9. A substrate for mounting electronic elements as described in claim 1, wherein the second element mounting area is located on the upper surface.

10. The electronic device mounting substrate according to claim 1 , further comprising a thermal via connected to the first device mounting region and / or the second device mounting region and penetrating the base along a thickness direction of the base.

11. The electronic device mounting substrate according to claim 1 , further comprising a heat sink located on the lower surface for dissipating heat generated from the light receiving element or the laser diode.

12. The electronic element mounting substrate according to claim 1 ; a light receiving element mounted in the first element mounting area; a laser diode mounted in the second element mounting area.

13. The substrate further has a first electrode located in the first step portion, The electronic device according to claim 12 , wherein the light-receiving element is connected to the first electrode by a bump.

14. The substrate, a second receiving hole located on the lower surface; a second step portion located within the second accommodating hole and in which the second element mounting region is located; a second electrode located on the second step portion; The electronic device according to claim 12 , wherein the laser diode is connected to the second electrode by a bump.

15. An electronic device according to any one of claims 12 to 14; a housing located on the top surface and covering the light receiving element and the laser diode; a first lens that overlaps the light receiving element in a planar perspective view and is held by the housing; an electronic module comprising: a second lens that overlaps the laser diode in a plan view and is held by the housing;

Images