Electrical element mounting substrate and electrical device

Abstract

This electrical element-mounting substrate comprises a first substrate having a ceramic material as a first base material, and a second substrate having an organic resin as a second base material. The first substrate has a first surface and a second surface positioned opposite the first surface. The first surface has a first mounting region for mounting an electrical element, and an installation unit for installing a lens holder or a window material. The installation unit is positioned surrounding the first mounting region in a planar view. The second substrate is positioned on the second surface of the first substrate.

Description

[Technical Field]

[0001] The disclosed embodiments relate to an electric element mounting substrate and an electric device. [Background technology]

[0002] For example, an imaging device has been proposed in which an imaging element is mounted on a substrate in which a ceramic substrate and an organic resin substrate are laminated. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 082923 Summary of the Invention

[0004] An electric element mounting substrate according to one aspect of the embodiment includes a first substrate having a ceramic as a first base material and a second substrate having an organic resin as a second base material. The first substrate has a first surface and a second surface located opposite the first surface. The first surface has a first mounting area where an electric element is mounted and a mounting portion where a lens holder or a window material is mounted. The mounting portion is located around the first mounting area in a plan view. The second substrate is located on the second surface of the first substrate. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a perspective view showing an example of an electric device according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the electrical device shown in FIG. [Figure 3] FIG. 3 is a perspective view showing an example of an electric device according to the second embodiment. [Figure 4] FIG. 4 is a cross-sectional view of the electrical device shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing an example of an electric device according to the third embodiment. [Figure 6]FIG. 6 is a cross-sectional view showing an example of an electric device according to the fourth embodiment. [Figure 7A] FIG. 7A is a cross-sectional view showing an example of an electric device according to a fifth embodiment. [Figure 7B] FIG. 7B is a cross-sectional view showing another example of the electric device according to the fifth embodiment. [Figure 8] FIG. 8 is an explanatory diagram showing a method for evaluating an electric element mounting board. DETAILED DESCRIPTION OF THE INVENTION

[0006] The following description primarily focuses on a substrate for mounting an imaging element, but it goes without saying that the present invention can also be applied to elements other than imaging elements. Examples of elements other than imaging elements include at least one element selected from the group consisting of circuit elements such as large-scale integrated circuits (LSIs), switch ASIC elements, superconducting elements (Josephson elements), SAW (surface acoustic wave) elements, light-emitting elements, logic elements, Hall elements, light-receiving elements, piezoelectric elements, Peltier elements, and metal film resistor elements. The electrical element mounted in the mounting area of ​​the electrical element mounting substrate is at least one of the elements described above. In other words, multiple elements of the same type may be mounted in the mounting area on the same surface, or different types of elements may be mounted. As shown below, elements may be mounted on one or both surfaces of the second substrate. Multiple elements may also be mounted on both surfaces of the second substrate.

[0007] In an imaging device in which an imaging element is mounted on a stacked substrate, for example, thermal deformation of the substrate may cause the optical axis of the imaging element to shift, leaving room for improvement in durability.

[0008] Therefore, there is a need for a highly durable imaging element mounting substrate and imaging device, and when the above-mentioned other elements are used, there is a need for a highly durable electrical element mounting substrate and electrical device.

[0009] Hereinafter, embodiments for carrying out an electric element mounting substrate and an electric device according to the present disclosure (hereinafter referred to as "embodiments") will be described in detail with reference to the drawings. Note that the electric element mounting substrate and the electric device according to the present disclosure are not limited to these embodiments. Furthermore, the embodiments can be appropriately combined within the scope of not causing any contradiction in the processing content.

[0010] (First embodiment) Fig. 1 is a perspective view showing an example of an electric device according to a first embodiment, and Fig. 2 is a cross-sectional view of the electric device shown in Fig. 1.

[0011] 1 and 2, an electric device 100 according to the first embodiment includes an electric element mounting board 1 and an imaging element 30. The electric element mounting board 1 has a first substrate 10 and a second substrate 20. The electric element mounting board 1 serves as a substrate or member on which the imaging element 30 is mounted.

[0012] The first substrate 10 has a ceramic insulating base material (first substrate 10a). The first substrate 10 has a mounting area 11 and an installation portion 12. The mounting area 11 is located in the center of a first surface 101, which is the upper surface of the first substrate 10. The mounting area 11 is an area where the imaging element 30 is mounted. The mounting area 11 provided on the first substrate 10 may be referred to as the first mounting area. The surface of the first substrate 10 where the mounting area 11 and the installation portion 12 are provided is referred to as the first surface 101, and the surface opposite the first surface 101 is referred to as the second surface 102.

[0013] The installation section 12 is located around the mounting area 11. In the case of the electric element mounting board 1 according to the first embodiment, the installation section 12 is located on the first surface 101, which is the upper surface of the first substrate 10. That is, in the case of the electric element mounting board 1 according to the first embodiment, the mounting area 11 and the installation section 12 are located on the same plane of the first surface 101. The mounting area 11 and the installation section 12 are located at the same height on the first surface 101. Because the electric element mounting board 1 has a flat plate-like shape, a lens holder 40 may be placed on the installation section 12, as shown in FIG. 2. The lens holder 40 has an opening 40a. A lens 40b is placed in the lens holder 40.

[0014] The second substrate 20 has an insulating base material (second base material 20a) made of organic resin. The second substrate 20 is laminated on the first substrate 10. The second substrate 20 is laminated on a second surface 102 located on the opposite side of the first surface 101 of the first substrate 10 where the first mounting area is located. Hereinafter, the surface of the second substrate 20 facing the first substrate 10 will be referred to as the third surface, and the surface opposite the third surface will be referred to as the fourth surface.

[0015] As described above, in the electric element mounting substrate 1 according to this embodiment, the mounting portion 12 for mounting the lens holder 40 is located around the mounting area 11 of the first substrate 10, which has a ceramic base material, in a plan view. Therefore, compared to when the lens holder 40 or window material is mounted on an organic base material, for example, it is possible to reduce lens positional shifts and optical axis shifts caused by thermal deformation. This allows the durability of the electric element mounting substrate 1 and the electric device 100 to be improved.

[0016] The imaging element 30 is mounted in the mounting area 11 (first mounting area) of the electric element mounting board 1. The imaging element 30 may be, for example, a CMOS (Complementary Metal Oxide Semiconductor) or a CCD (Charge Coupled Device).

[0017] The first substrate 10a is, for example, a ceramic substrate made of ceramic. The first substrate 10a may be, for example, an alumina-based or glass-ceramic-based ceramic, or may be a dielectric material such as cordierite, zirconia, barium titanate, strontium titanate, or calcium titanate, or aluminum titanate, lead zirconate titanate (PZT), or the like. The first substrate 10a may also include, for example, a plurality of ceramics.

[0018] Furthermore, a conductor layer (surface conductor layer) may be formed on the surface of the first base material 10a as needed. Such a conductor layer may be, for example, a line-shaped wiring, a circular, rectangular, or other angular pad, or a solid power supply layer or ground layer. The conductor located on the surface of the first base material 10a may be, for example, smaller in area than the main surface of the first substrate 10.

[0019] The first substrate 10 may also have an internal conductor layer (internal conductor layer). It may also have an interlayer connection conductor that electrically connects the surface conductor layer and the internal conductor layer. Materials for the surface conductor layer, the internal conductor layer, and the interlayer connection conductor may be, for example, tungsten (W), molybdenum (Mo), a W-Mo mixture, a W-Mo alloy, a W-Mo intermetallic compound, copper, silver, or nickel. The surface conductor layer, the internal conductor layer, and the interlayer connection conductor may also contain a co-material such as ceramic powder.

[0020] The interlayer connection conductor may contain, for example, copper powder, tin (Sn) powder, or bismuth (Bi) powder. The interlayer connection conductor may also contain the remainder of the same material as the second substrate 20a (described later), such as epoxy resin. The interlayer connection conductor preferably has a melting point closer to the heat resistance temperature of the organic resin second substrate 20 than that of the ceramic first substrate 10a.

[0021] The second substrate 20a is, for example, an organic substrate made of an organic material. The second substrate 20a may be, for example, an epoxy resin, an acrylic resin, a polycarbonate resin, a polyimide resin, an olefin resin, or a polyphenylene resin. The second substrate 20a may also be, for example, polytetrafluoroethylene (PTFE) or other fluororesins or polyphenylene ether resins.

[0022] As described above, in the electric element mounting substrate 1 according to this embodiment, the second substrate 20 that constitutes part of the electric element mounting substrate 1 is made of organic resin. This allows the electric element mounting substrate 1 and the electric device 100 to be lighter in weight than when only a substrate based on ceramic is included.

[0023] (Second embodiment) Fig. 3 is a perspective view showing an example of an electric device according to a second embodiment, and Fig. 4 is a cross-sectional view of the electric device shown in Fig. 3.

[0024] 3 and 4, an electric device 100 according to the second embodiment includes an electric element mounting board 1 and an imaging element 30. The electric element mounting board 1 has a first substrate 10 and a second substrate 20. In this case as well, the electric element mounting board 1 serves as a substrate or member for mounting the imaging element 30.

[0025] In the case of the electric device 100 according to the second embodiment, the first substrate 10 constituting the electric element mounting substrate 1 has a recess 13. The recess 13 is located in the center of the first substrate 10 so as to have an opening on the first surface 101 of the first substrate 10. In this case, the surface that is the bottom of the recess 13 is the bottom surface 14. The bottom surface 14 is a portion that corresponds to the mounting region 11 (first mounting region) in the electric element mounting substrate 1 according to the second embodiment. The imaging element 30 is mounted on the bottom surface 14 of the recess 13, as shown in FIGS. 3 and 4.

[0026] In the electric element mounting board 1 according to the second embodiment, the installation section 12 for installing the lens holder 40 or window member 41 is positioned around the bottom surface 14 on which the imaging element 30 is mounted in a plan view. The installation section 12 is provided on the first surface 101 of the electric element mounting board 1. The installation section 12 and the bottom surface 14 on which the imaging element 30 is mounted are located at different height positions when the electric element mounting board 1 is viewed in vertical cross section. In the electric element mounting board 1 according to the second embodiment, the imaging element 30 can be disposed within the recess 13. The upper surface of the imaging element 30 can be positioned lower in the height direction than the first surface 101 of the electric element mounting board 1. For example, a flat window member 41 can be used for the installation section 12. In the electric device 100 according to the second embodiment, the imaging element 30 does not protrude from the first surface 101 of the electric element mounting board 1. This makes the imaging element 30 less susceptible to external and mechanical damage, enabling high reliability.

[0027] The window material 41 may be a light-transmitting material such as glass. A window 41a, which is an area that can be imaged by the imaging element 30, is located inside the installation section 12. Note that instead of the window material 41, a lens holder 40 may be installed.

[0028] In this way, even when the first substrate 10 has the recess 13, the installation portion 12 for installing the window material 41 or the lens holder 40 can be positioned around the bottom surface 14 on which the imaging element 30 is mounted in a plan view. Therefore, compared to when the window material 41 or the lens holder 40 is installed on an organic base material, it is possible to reduce, for example, misalignment of the window material 41 and the lens 40b and misalignment of the optical axis caused by thermal deformation of the electric element mounting substrate 1. This allows the durability of the electric element mounting substrate 1 and the electric device 100 to be improved.

[0029] Furthermore, when the first substrate 10 has a so-called cavity structure having a recess 13, for example, a flat, entirely transparent plate can be used as the window material 41. This increases light transmittance, allowing more video information to be captured.

[0030] Although the first substrate 10 shown in FIG. 4 is illustrated as having a laminated structure, the recess 13 may be provided on a single-layer first substrate 10.

[0031] 4, the electric device 100 according to the second embodiment has a step 13a between the first surface 101 and the bottom surface 14 in the depth direction of the recess 13. In this case, if a terminal electrode 13b is provided on the step 13a, it becomes possible to connect a bonding wire 30a extending from the imaging element 30 to this terminal electrode 13b. It is preferable that the top surface 30b of the imaging element 30 and the step 13a are at the same or similar heights from the bottom surface 14. If the top surface 30b of the imaging element 30 and the step 13a are at similar heights, it becomes possible to shorten the length of the wire 30a from the imaging element 30. This makes it possible to reduce an increase in inductance caused by the length of the wire 30a.

[0032] In the electric device 100 of the first embodiment and the electric device 100 of the second embodiment described above, the Young's modulus of the first substrate 10 may be higher than that of the second substrate 20. Furthermore, the Young's modulus of the first substrate 10 may be higher than that of the window material 41. Furthermore, the Young's modulus of the first substrate 10 may be higher than that of the material of the lens holder 40. In other words, the Young's modulus of the window material 41 and the Young's modulus of the lens holder 40 may be lower than that of the first substrate 10. The Young's modulus of the second substrate 20 may be lower than that of the first substrate 10. The electric device 100 has the window material 41, the first substrate 10, and the second substrate 20 stacked in this order. In such a stacked structure, if the first substrate 10, which has a higher Young's modulus, is positioned at the center in the stacking direction, the first substrate 10 positioned at the center in the stacking direction serves as a pivot, thereby reducing the overall deformation of the electric device 100. In this case, the Young's modulus may be measured using a sample piece cut out from the electrical device 100, or a value measured using a separately prepared member having a composition corresponding to that of each base material may be used. Here, the main component refers to the component that is contained in the largest amount in the base material in terms of mass ratio or volume ratio.

[0033] (Third embodiment) 5 is a cross-sectional view showing an example of an electric device according to the third embodiment. First, in the electric device 100 according to the third embodiment, the electric element mounting board 1 has the same configuration as the electric element mounting board 1 of the first embodiment and the electric element mounting board 1 of the second embodiment described above. That is, in the case of the electric device 100 according to the third embodiment, the electric element mounting board 1 is also a laminate of a first substrate 10 and a second substrate 20. Furthermore, the mounting structure of the imaging element 30 on the electric element mounting board 1 is also the same as in the case of the electric device 100 according to the second embodiment described above.

[0034] In the electric device 100 of the third embodiment, the second substrate 20 has a conductor 20b. The conductor 20b may be provided on the surfaces (faces 201 and 202) and inside 203 of the second substrate 20. As shown in Fig. 5, the conductor 20b may be arranged so as to connect from face 201, which is one surface of the second substrate 20, to face 202, which is the other surface.

[0035] In this case, the conductor 20b located on the second substrate 20 may have a smaller width or diameter than the conductor located on the first substrate 10. For example, when the conductor 20b has internal conductor layers 20b1, 20b2 and interlayer connection conductors 20b3, 20b4, the width of the internal conductor layers 20b1, 20b2 and / or the diameter of the interlayer connection conductors 20b3, 20b4 may be smaller than the width of the surface conductor layer located on the first substrate 10 and / or the diameter of the interlayer connection conductor. This makes it difficult for heat to be transmitted from the second substrate 20 side to the first substrate 10 side via the conductors, for example.

[0036] (Fourth embodiment) FIG. 6 is a cross-sectional view showing an example of an electric device according to a fourth embodiment. In the electric device 100 according to the fourth embodiment, the second substrate 20 has a heat dissipation section 22. The heat dissipation section 22 is a portion of the second substrate 20 that is close to the surface 202. The heat dissipation section 22 may have a higher volume ratio of conductors 20b than other regions 22a within the surface 202 of the second substrate 20. In this case, the heat dissipation section 22 of the second substrate 20 has a higher heat dissipation capability than the other regions 22a. The heat dissipation section 22 may be arranged so as to surround the periphery of the surface 202 of the second substrate 20. This can further improve the heat dissipation from the second substrate 20.

[0037] The central region 21 of the second substrate 20 excluding the heat dissipation section 22 may be used as a mounting section for electric elements on the second substrate 20. The heat dissipation section 22 may be arranged so that the conductor 20b extends from the surface 201 of the second substrate 20 that contacts the first substrate 10 to the surface 202 of the second substrate 20 located on the opposite side to the surface 201, in the thickness direction of the second substrate 20, and outward from the surface 202.

[0038] That is, central region 21 is located in the center of surface 202, which is the main surface of second substrate 20, and is a region where electrical elements are mounted. Heat dissipation section 22 is located around region 21 and is a portion that dissipates heat. Conductors 20b located on second substrate 20 may be exposed on surface 202 of heat dissipation section 22. Heat transferred from imaging element 30 via first substrate 10 is dissipated from the surface of heat dissipation section 22 to surface 202 where conductors 20b are exposed. In this way, according to electric device 100 of the fourth embodiment, heat can be dissipated, for example, from the first substrate 10 side to the second substrate 20 side. Even when electrical elements are mounted in central region 21, heat easily flows to heat dissipation section 22 around central region 21, thereby preventing problems caused by heat flowing into the electrical elements.

[0039] Furthermore, the electric device 100 according to this embodiment may have a heat collecting member 50 on the surface 202 that serves as the heat dissipation section 22. The heat collecting member 50 is located, for example, at the heat dissipation section 22 of the second substrate 20, which is located around the central region 21 (second mounting region). The heat collecting member 50 is located so as to be in contact with the surface 202 of the second substrate 20. The heat collecting member 50 is, for example, a metal member. The heat collecting member 50 can collect heat conducted through the conductor 20b and release it to the outside air. In this way, the heat collecting member 50 can dissipate heat mainly originating from the imaging element 30, for example, in a manner that further reduces the thermal impact on other electric elements from the first substrate 10 side to the second substrate 20 side. The heat dissipation section 22 or the heat collecting member 50 may be located so as to surround the region 21. The heat dissipation section 22 or the heat collecting member 50 may be a wall member that surrounds the region 21 on all four sides. If the heat dissipation section 22 or the heat collecting member 50 is configured as a wall member surrounding the region 21 on all sides, it can have the function of protecting the electric element 60 mounted in the region 21, which will be described later, from mechanical shocks, etc. In this case, it is preferable that the height of the heat dissipation section 22 or the heat collecting member 50 is greater than the height of the electric element 60.

[0040] Furthermore, the electric device 100 according to this embodiment may have a connector 80 for electrically connecting to an external power source. If the heat collecting member 50 has a divided structure, a part of the heat collecting member 50 may serve as the connector 80.

[0041] (Fifth embodiment) FIG. 7A is a cross-sectional view showing an example of an electric device according to a fifth embodiment. The electric device 100 according to the fifth embodiment has an electric element 60 located on the surface 202 of the second substrate 20. The electric element 60 is located in the region 21 and is bonded to the surface 202 of the region 21 via a bonding material 65. The electric element 60 may be, for example, a semiconductor element for signal processing. The bonding material 65 may be, for example, conductive and electrically connect the second substrate 20 and the electric element 60. In the electric device 100 according to the fifth embodiment, the image sensor 30 is disposed on the bottom surface 14 of the recess 13 of the first substrate 10. The electric element 60 is also disposed on the surface 202 of the second substrate 20 stacked on the first substrate 10. The image sensor 30 and the electric element 60 overlap in a planar perspective view. Even if the areas of the image sensor 30 and the electric element 60 differ, it is preferable that either the image sensor 30 or the electric element 60 be entirely within the plane of the other element. This allows the wiring length between the imaging element 30 and the electrical element 60 to be as short as possible, equivalent to the thickness of the first substrate 10 and the second substrate 20 stacked together, thereby obtaining an electrical device 100 with low inductance.

[0042] The second base material 20a constituting the second substrate 20 may have a smaller relative dielectric constant than the first base material 10a constituting the first substrate 10. This allows signal delay to be reduced even when, for example, an electric element with a higher operating frequency is arranged closer to the second substrate 20 than to the first substrate 10.

[0043] The electric device 100 may also include a heat dissipation member 70. The heat dissipation member 70 is provided on the surface of the electric element 60 opposite to the surface on which the bonding material 65 is provided. The heat dissipation member 70 serves to quickly dissipate heat generated in the electric element 60. This reduces the heat generated in the electric element 60 from being transmitted to the imaging element 30 through the electric element mounting board 1, thereby reducing, for example, lens positional deviation and optical axis deviation due to thermal deformation compared to when the heat dissipation member 70 is not provided. This increases the durability of the electric element mounting board 1 and the electric device 100. The heat dissipation member 70 may be, for example, a heat sink or fin member. If the heat sink is a solid object, fin members may be layered on the heat sink.

[0044] Furthermore, in the case of the electric element mounting board 1 constituting the electric device 100 according to the fifth embodiment, similarly to the electric element mounting board 1 constituting the electric device 100 according to the fourth embodiment, it is preferable that the second substrate 20 has a conductor 20b, and a part of the conductor 20b forms the heat dissipation portion 22 on the peripheral portion of the surface 202. Note that in the case of the electric element mounting board 1 constituting the electric device 100 according to the fifth embodiment, the second substrate 20 may have a metal member inside.

[0045] Such metal member 20c may be disposed separately from conductor 20b, is not electrically connected, and merely contributes to heat dissipation. That is, metal member 20c located inside second substrate 20 has a portion exposed on the side surface of second substrate 20, but metal member 20c is preferably insulated from conductor 20b that constitutes the electrical circuit. This allows heat to be dissipated in a manner that minimizes the thermal impact on other electronic elements from the first substrate 10 side to the second substrate 20 side.

[0046] The material of the conductor 20b and the metal member 20c of the second substrate 20 may be the same as the material of the conductor of the first substrate 10. Furthermore, the conductor 20b and the metal member 20c may have the same shape and size.

[0047] 7A may be configured such that the electric element 60, the second substrate 20, and the first substrate 10 are laminated in this order. Fig. 7B is a cross-sectional view showing another example of the electric device according to the fifth embodiment.

[0048] 7B, the electric element 60 may be disposed in a mounting area of ​​the second substrate 20. Furthermore, the first substrate 10 may be disposed on the side of the second substrate 20 opposite to the surface on which the electric element 60 is disposed.

[0049] The second substrate 20 may have a mounting area on one of its main surfaces for mounting the electric elements 60. The first substrate 10 may be disposed on the main surface of the second substrate 20 opposite to the surface on which the electric elements 60 are mounted.

[0050] In this case, the second substrate 20 may have a lower Young's modulus than the first substrate 10. If the second substrate 20 with the lower Young's modulus is the substrate on which the electric element 60 is mounted, the stress on the electric element 60 is reduced, thereby reducing the probability of failure. This means that even if the electric element mounting substrate 1 is placed in a severe temperature environment such as an extremely low temperature, failure of the electric element 60 and the electric element mounting substrate 1 can be prevented.

[0051] 7A. That is, of the conductors 20b of the second substrate 20, the central conductor where the internal conductor layer 20b1 and the interlayer connection conductor 20b3 are connected may be located on the mounting area side of the electric element 60 when the electric element mounting board 1 is viewed in the stacking direction.

[0052] On the other hand, the conductor connecting the internal conductor layer 20b2 and the interlayer connection conductor 20b4 may be located closer to the surface opposite the mounting area of ​​the electric element 60 when viewed in the stacking direction of the electric element mounting board 1. In this case, the conductor connecting the internal conductor layer 20b2 and the interlayer connection conductor 20b4 may be located around the mounting area when the electric element mounting board 1 is seen through from above.

[0053] The conductor connecting the internal conductor layer 20b2 and the interlayer connecting conductor 20b4 may extend in a stepped manner in the stacking direction of the electrical element mounting substrate 1 from the central conductor connecting the internal conductor layer 20b1 and the interlayer connecting conductor 20b3 when the electrical element mounting substrate 1 is viewed in vertical cross section.

[0054] In this case, it is preferable that the central conductor connecting the internal conductor layer 20b1 and the interlayer connection conductor 20b3 and the conductor connecting the internal conductor layer 20b2 and the interlayer connection conductor 20b4 are connected to each other because this increases thermal conductivity between them. The central conductor connecting the internal conductor layer 20b1 and the interlayer connection conductor 20b3 and the conductor connecting the internal conductor layer 20b2 and the interlayer connection conductor 20b4 allow heat generated by the electric element 60 to be dissipated from the outside of the electric element mounting substrate 1. This improves the stability of the operation of the electric element 60. Here, the outside of the electric element mounting substrate 1 refers to the thickness direction from the mounting area of ​​the electric element mounting substrate 1 to the opposite side, as well as the direction of the side of the substrate.

[0055] The electric element 60 may be at least one selected from the group consisting of, for example, a circuit element represented by a large-scale integrated circuit (LSI), a switch ASIC element, a superconducting element (Josephson element), a SAW (surface acoustic wave) element, a light-emitting element, a logic element, a Hall element, a light-receiving element, a piezoelectric element, a Peltier element, a metal film resistor element, etc. In these cases, the electric element mounting substrate 1 will also be highly durable.

[0056] (Other embodiments) In each of the above-described embodiments, the first substrate 10 and the second substrate 20 may have the same area in a plan view. This allows the second substrate 20 to be positioned so as to overlap the entire second surface 102 of the first substrate 10, which is opposite the first surface 101 on which the first mounting area is located. This makes it less likely that local warping will occur in both the first substrate 10 and the second substrate 20 when the two substrates are stacked. This allows for increased durability of the electric element mounting substrate 1 and the electric device 100.

[0057] In other words, the first substrate 10 and the second substrate 20 may overlap with the same shape and size in a planar perspective. When the first substrate 10 and the second substrate 20 overlap with the same shape and size in a planar perspective, the effect of preventing local deformation of the first substrate 10 and the second substrate 20 from occurring is enhanced. For example, when the first substrate 10 and the second substrate 20 overlap, if the area of ​​the first substrate 10 is larger than the area of ​​the second substrate 20, deformation is likely to occur due to the portion of the first substrate 10 that protrudes from the second substrate 20. Furthermore, if the area of ​​the second substrate 20 is larger than the area of ​​the first substrate 10, deformation is likely to occur due to the portion of the second substrate 20 that protrudes from the first substrate 10. The presence of the protruding portion of one substrate is likely to cause deformation. For this reason, it is preferable that the side surfaces of the first substrate 10 and the second substrate 20 are overlapped so that they are flush with each other. In this case, referring to Figure 1, it is preferable that the first substrate 10 and the second substrate 20 are arranged such that the four side surfaces of the second substrate 20 arranged in the stacking direction are flush with the four side surfaces of the first substrate 10.

[0058] Furthermore, in each of the above-described embodiments, the first substrate 10 and the second substrate 20 may be bonded by a resin component contained in the second substrate 20. This makes it difficult for components other than the components contained in the first substrate 10 and the second substrate 20 to be present at the lamination interface between the first substrate 10 and the second substrate 20, thereby improving the thermal conductivity between the first substrate 10 and the second substrate 20.

[0059] (Method of manufacturing a substrate for mounting electric elements) Next, an example of a method for manufacturing the electric element mounting substrate 1 according to the embodiment will be described.

[0060] First, a method for producing a first substrate 10 having a ceramic insulating base material will be described. The final shape can be, for example, 10 mm square with a thickness t=1 mm (five insulating layers, each 0.2 mm thick). The diameter (via diameter) of the interlayer connection conductors that penetrate each insulating layer can be, for example, 200 μm.

[0061] First, a pattern sheet is prepared by forming a conductive pattern including vias on a ceramic green sheet (ceramic green sheet). Examples of such a ceramic green sheet include a ceramic material containing alumina as a main component, and glass ceramics.

[0062] As a ceramic material mainly composed of alumina, for example, 100 parts by mass of alumina raw material powder to which 10 to 20 parts by mass of SiO2 and MgO have been added can be used. Furthermore, additives such as MnO may also be added. The amounts of SiO2 and MgO should preferably be approximately equal. The mass ratio of MnO should preferably be 1 / 10 to 1 / 2 of the total amount of SiO2 and MgO.

[0063] As the glass ceramic, for example, borosilicate glass containing inorganic particles such as alumina or silica can be used.

[0064] Furthermore, the type of metal powder used as the main component of the conductor pattern differs between ceramic materials whose main component is alumina and glass ceramics. For example, in the case of a ceramic green sheet made of a ceramic material whose main component is alumina, a conductor paste containing, for example, tungsten (W) or molybdenum (Mo) may be used as the material for the conductor pattern, since co-firing is possible.

[0065] Furthermore, for ceramic green sheets formed from glass ceramics, it is preferable to use, as the conductor pattern, a metal material such as copper or silver, which sinters at a lower temperature than tungsten or molybdenum.

[0066] In order to improve the transmission characteristics of the conductor, the pattern sheet may be formed by combining a conductor paste containing, for example, copper or silver, which has high conductivity, as its main component, with glass ceramics.

[0067] The patterned sheets thus obtained are stacked and fired, for example, at 1500°C to 1800°C for ceramic materials containing alumina as the main component, and at 800°C to 1100°C for ceramic materials containing glass ceramic as the main component.

[0068] Furthermore, if necessary, a plating film of Ni, Au, or the like may be formed on the surface of the conductor exposed on the surface of the first substrate 10.

[0069] This forms the first substrate 10 according to each embodiment. Note that an inorganic or organic adhesive may be applied to the portion where the window material 41 (see FIGS. 3 and 4) is to be attached.

[0070] Next, a method for producing the second substrate 20 having an insulating base material made of organic resin will be described. The final shape can be, for example, 10 mm square with a thickness t=0.2 mm (two insulating layers each 0.1 mm thick). The diameter (via diameter) of the interlayer connection conductor penetrating each insulating layer can be, for example, 200 μm. The metal member of the second substrate 20 can be, for example, copper foil having a thickness of 18 μm.

[0071] First, a varnish is prepared by adding an inorganic filler such as silica to an epoxy resin, and a green sheet is produced from the varnish.

[0072] Next, conductors are formed on the prepared green sheet. Among the conductors, via conductors located in the thickness direction of the green sheet can be formed, for example, by drilling holes through the green sheet in the thickness direction and then filling the formed through holes with a conductive paste. In this case, it is preferable to use a composite metal powder in which a low-melting-point metal is added to copper or silver powder. Examples of low-resistance metal materials include tin (Sn), solder (Sn-Pb), bismuth (Bi), and antimony (Sb).

[0073] The conductive paste may contain, as a binder, one or more organic resins selected from the group consisting of epoxy resin, acrylic resin, polyethylene resin, etc. The binder is preferably 1 to 20 parts by mass per 100 parts by mass of the metal component.

[0074] Furthermore, among the conductors, the ground layer and wiring may use copper foil patterns formed by etching copper foil. The copper foil pattern may be processed into a pattern shape by performing exposure and development processes while the copper foil is attached to a resin film. The copper foil pattern obtained by pattern processing is transferred to a green sheet. For example, the transfer can be performed by attaching the copper foil pattern to the green sheet and then peeling off the resin film that serves as the base material.

[0075] In this way, a green sheet (pattern sheet) on which via conductors and copper foil patterns are formed is produced. This pattern sheet is laminated as is on the back surface of the first substrate 10 (for example, the second surface 102 shown in FIG. 4). Next, a laminate is produced by treating, for example, at a temperature of 70°C, under a pressure of about 1 MPa to 5 MPa, and for a heating time of 20 to 30 seconds. The produced laminate is cured at 200°C to 250°C for 2 to 4 hours. If necessary, plating (Ni, Au, etc.) may be formed on the conductor surface.

[0076] Furthermore, a solder resist may be formed on the second substrate 20 in areas other than the copper foil pattern.

[0077] In this manner, the second substrate 20 according to each embodiment is formed, and the electric element mounting substrate 1 in which the first substrate 10 and the second substrate 20 are stacked is fabricated.

[0078] (Experimental example) Electric element mounting substrates 1 according to Samples 1 to 3 shown below were prepared and their properties were evaluated.

[0079] (Preparation of Sample 1) Fig. 8 is an explanatory diagram showing a method for evaluating an electric element mounting substrate. First, an electric element mounting substrate 1 (10 mm square) shown in Figs. 3 and 4 was prepared, and a glass plate with a thickness of 0.1 mm was attached as a window material 41. Epoxy resin was used as an adhesive.

[0080] The ring 91 was formed in the center of the window material 41 using Ag paste so that the outer diameter (diameter) was 5 mm and the inner diameter was 3 mm.

[0081] (Preparation of Sample 2) Except for using the electric element mounting substrate disclosed in Patent Document 1, Sample 2 was prepared in the same manner as Sample 1. Specifically, an electric element mounting substrate was prepared which included a first substrate having a recess on its upper surface and containing an organic material, and a second substrate located in the recess of the first substrate, having a mounting area on its upper surface for mounting an imaging element, and containing an inorganic material, and window member 41 was attached to the electric element mounting substrate.

[0082] (Preparation of sample 3) Sample 3 was obtained in the same manner as Sample 1, except that the materials of the first substrate 10 and the second substrate 20 were swapped, with the insulating base material of the first substrate 10 being an organic resin and the insulating base material of the second substrate 20 being ceramic.

[0083] <Evaluation> While shining light from a light source 90 arranged on the window material 41 side onto the electric element mounting substrate 1 to which the window material 41 was attached, the electric element mounting substrate 1 was heated with a heater and the temperature was changed from room temperature (25°C) to 100°C, and the degree of deformation of the window material 41 was evaluated from the change in size of the ring 91 formed on the window material 41. The change in size of the ring 91 was evaluated by the expansion coefficient. Specifically, when the outer diameter of the ring 91 in the initial state was L0 (mm) and the outer diameter of the ring 91 after the evaluation test was L1 (mm), the expansion coefficient was calculated as (L1 - L0) / L0 x 100 (%).

[0084] In the electric element mounting substrate 1 of Sample 1, the expansion coefficient of the ring 91 was 0.7%. In contrast, in the electric element mounting substrates of Samples 2 and 3, the expansion coefficients of the ring 91 were 4% and 6%, respectively. In Sample 1, the window material 41 is fixed to the first substrate 10 having a ceramic insulating base material, and therefore it is thought that the window material 41 was less likely to deform than in Samples 2 and 3, in which the window material 41 was fixed to a substrate having an insulating base material of organic resin.

[0085] As described above, the electric element mounting substrate 1 according to the embodiment includes a first substrate 10 having a ceramic first base material 10a and a second substrate 20 having an organic resin second base material 20a. The first substrate 10 has a first mounting area (e.g., mounting area 11) for mounting an electric element (e.g., image sensor 30) and a mounting portion 12 for mounting a lens holder 40 or a window material 41. The first mounting area is located on the upper surface of the first substrate 10. The mounting portion 12 is located around the first mounting area in a plan view. The second substrate 20 is stacked on the surface of the first substrate 10 opposite the first mounting area.

[0086] Therefore, the electric element mounting substrate 1 according to the embodiment has high durability.

[0087] Further advantages and other aspects may readily occur to those skilled in the art. Therefore, the disclosure in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0088] 1. Electrical element mounting board 10 First board 10a 1st base material 11 Mounting area (first mounting area) 12 Installation part 13 Recess 14 Bottom 20 Second board 20a 2nd base material 21 areas 30 Image sensor 40 Lens holder 41 Window materials 50 Heat collecting parts 60 Electrical Elements 70 Heat dissipation material 80 Connector 100 Electrical Equipment

Claims

1. a first substrate having a ceramic as a first base material; a second substrate having an organic resin as a second base material; Equipped with the first substrate has a first surface and a second surface opposite the first surface; the first surface has a first mounting area for mounting a first electric element and an installation portion for installing a lens holder or a window material; the installation portion is located around the first mounting area in a plan view, The second substrate is bonded to the second surface of the first substrate by a resin component contained in the second substrate without an adhesive layer or adhesive member. A substrate for mounting electrical elements.

2. the first substrate has a recess on the first surface; The first mounting area is located on the bottom surface of the recess. The electrical element mounting substrate according to claim 1 .

3. The first substrate and the second substrate have the same area in a plan view. The electrical element mounting substrate according to claim 1 .

4. The second substrate has a smaller relative dielectric constant than the first substrate. The electrical element mounting substrate according to claim 1 .

5. The conductor located on the second substrate has a smaller width or diameter than the conductor located on the first substrate. The electrical element mounting substrate according to claim 4 .

6. The lens holder or the window material is mounted on the first substrate. The electrical element mounting substrate according to claim 1 .

7. A step is provided between the first surface and the bottom surface in the depth direction of the recess. The electrical element mounting substrate according to claim 2 .

8. The lens holder or the window material, the first substrate, and the second substrate are arranged in this order. The electrical element mounting substrate according to claim 1 .

9. The Young's modulus of the first substrate is higher than the Young's modulus of the second substrate, the material of the lens holder, and the window material. The electrical element mounting substrate according to claim 8 .

10. the second substrate has a second mounting area for mounting a second electric element on a surface opposite to the first substrate, The Young's modulus of the second substrate is lower than the Young's modulus of the first substrate. The electrical element mounting substrate according to claim 1 .

11. The first mounting area and the second mounting area overlap in plan view. The electrical element mounting substrate according to claim 10.

12. the second substrate has a metal member therein as a heat dissipation member, The metal member is not electrically connected, is disposed separately from the conductor, and is insulated from the conductor that constitutes the electrical circuit. The electrical element mounting substrate according to claim 5 .

13. the first substrate and the second substrate each have a side surface, The side surface of the first substrate and the side surface of the second substrate are flush with each other. The electrical element mounting substrate according to claim 1 .

14. the first substrate and the second substrate each have four side surfaces; The first substrate and the second substrate are arranged such that four side surfaces of the second substrate arranged in the stacking direction are flush with four side surfaces of the first substrate. The electrical element mounting substrate according to claim 1 .

15. An electric element mounting substrate according to any one of claims 1 to 14, and an imaging element. Electrical equipment.

Images