Electronic equipment and multi-stage circuit boards

Abstract

To ensure high bonding strength between adjacent intermediate substrates without impairing functionality.SOLUTION: A first circuit pattern is formed on at least one surface of a top substrate in a thickness direction, and a second circuit pattern is formed on at least one surface of a bottom substrate in the thickness direction. An intermediate substrate has a plurality of connection conductors at both ends that can be connected to the first circuit pattern and the second circuit pattern through bumps, respectively, and is positioned between the top substrate and the bottom substrate. The plurality of intermediate substrates are formed as a facing portion in which portions of each substrate are placed facing each other. The facing portion has a bonded portion provided with a plated portion, and a non-bonded portion not provided with a plated portion. An injection groove, that opens at least on the top substrate side and into which solder is injected, is formed in the bottom substrate or the intermediate substrate. The solder injected into the injection groove in a state where the bonded portions of adjacent intermediate substrates face each other flows between the bonded portions due to a capillary phenomenon during heating by reflow.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] This technology relates to the technical field of a multi-layer substrate having a top substrate, a bottom substrate, and an intermediate substrate, and an electronic device including the same.

Background Art

[0002] Inside various electronic devices such as imaging devices and mobile phones, circuit boards on which control circuits and the like are formed are arranged. Among these circuit boards, there are multi-layer substrates in which a plurality of substrates are connected in the thickness direction (see, for example, Patent Document 1).

[0003] For such a multi-layer substrate, a mounting method called stack mounting in which an intermediate substrate formed in a frame shape as a whole is mounted between a top substrate and a bottom substrate is used. With stack mounting, electronic components are mounted in a space formed inside the intermediate substrate between the top substrate and the bottom substrate.

[0004] In a multi-layer substrate in which such stack mounting is performed, by forming circuits on both surfaces of each substrate and positioning electronic components in the space inside the intermediate substrate, it is possible to enhance functionality in a state where the projected area is reduced, and to miniaturize the electronic device while enhancing its functionality.

[0005] The intermediate substrate of a multi-layer substrate in which stack mounting is performed is called an interposer substrate. In addition to the type formed in a frame shape, there is also a type formed in a strip shape, and generally, the thickness is about 2 mm.

[0006] A plurality of connection conductors whose both ends are exposed on both surfaces in the thickness direction are formed on the intermediate substrate. A predetermined connection conductor is joined to a first circuit pattern of the top substrate and a second circuit pattern of the bottom substrate via bumps formed by soldering or the like, whereby the first circuit pattern and the second circuit pattern are connected via the connection conductor.

[0007] By the way, in multi-stage circuit boards where stack mounting is performed as described above, it is necessary to improve the strength against impacts that occur when electronic devices are dropped, etc.

[0008] To improve strength, it is desirable to use a frame-shaped intermediate substrate. However, since intermediate substrates are formed by cutting a portion of a flat base plate, when a frame-shaped intermediate substrate is formed, the inner portion of the intermediate substrate becomes waste, which is a disadvantage. Consequently, the number of intermediate substrates formed from a single base plate decreases, increasing the manufacturing cost of multi-layer substrates.

[0009] On the other hand, when multiple intermediate substrates formed in a strip shape are used, the number of intermediate substrates formed from a single base plate increases, which can reduce the manufacturing cost of multi-stage substrates. However, because gaps exist between adjacent intermediate substrates, it is difficult to ensure sufficient strength against impact.

[0010] Therefore, when intermediate substrates formed in a strip shape are used, adjacent intermediate substrates can be joined by adhesive or solder, thereby reducing the manufacturing cost of multi-layer substrates while increasing their resistance to impact. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 7-86751 [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] As described above, in multi-layer circuit boards, adjacent intermediate boards formed in a strip shape are joined together by adhesive or solder, making it possible to reduce manufacturing costs while ensuring high strength against impact.

[0013] However, when joining adjacent intermediate boards by adhesive, if the bonding process is performed after reflow soldering, the presence of a top board and a bottom board on both sides in the thickness direction of the intermediate board makes it difficult to insert the adhesive dispenser into the gap between adjacent intermediate boards. This can result in insufficient adhesive being injected into the gap, potentially leading to insufficient bonding strength between adjacent intermediate boards.

[0014] Furthermore, when joining adjacent intermediate substrates by adhesive, if the bonding process is performed before reflow soldering, the adhesive needs to have sufficient heat resistance to withstand the heat generated during reflow soldering. Depending on the type of adhesive, this may result in insufficient bonding strength between adjacent intermediate substrates.

[0015] On the other hand, when joining adjacent intermediate boards with solder, solder is injected into the gap between adjacent intermediate boards using a dispenser or the like while the intermediate boards are positioned between the top and bottom boards. However, because the intermediate boards are thick, about 2 mm, it is necessary to inject a sufficient amount of solder into the gap between adjacent intermediate boards to ensure sufficient bonding strength between them.

[0016] However, if too much solder is injected, it may flow into the gaps between the top and intermediate boards, or between the bottom and intermediate boards, and adhere to the connecting conductors, potentially causing a short circuit and impairing functionality. Therefore, it is desirable to limit the amount of solder injected into the gaps between adjacent intermediate boards. However, in this case, there is a possibility that a sufficient amount of solder will not be injected into the gaps between adjacent intermediate boards, and it may become impossible to ensure sufficient bonding strength between adjacent intermediate boards.

[0017] Therefore, the purpose of this technology for electronic equipment and multi-stage substrates is to ensure high bonding strength between adjacent intermediate substrates without compromising functionality. [Means for solving the problem]

[0018] The electronic device according to this technology has a multi-stage circuit board having a top board, a bottom board, and a plurality of intermediate boards arranged inside, a first circuit pattern formed on at least one surface in the thickness direction of the top board, a second circuit pattern formed on at least one surface in the thickness direction of the bottom board, and the intermediate board has a plurality of connecting conductors at both ends that can be connected to the first circuit pattern and the second circuit pattern via bumps, and is located between the top board and the bottom board, and a plurality of the intermediate boards of each part teeth Formed as opposing portions positioned opposite each other, the opposing portions have a joint portion provided with a plated portion and a non-joint portion not provided with the plated portion, the bottom substrate or the intermediate substrate has an injection groove that opens to the top substrate side and into which solder is injected, and the joint portions of adjacent intermediate substrates face each other. Furthermore, the joint portion is positioned continuously with the injection groove. In this state, the solder injected into the injection groove flows between the joints by capillary action when heated by reflow.

[0019] The multi-stage substrate according to this technology comprises a top substrate, a bottom substrate, and a plurality of intermediate substrates, wherein a first circuit pattern is formed on at least one surface in the thickness direction of the top substrate, a second circuit pattern is formed on at least one surface in the thickness direction of the bottom substrate, and the intermediate substrate has a plurality of connecting conductors at both ends that can be connected to the first circuit pattern and the second circuit pattern via bumps, and is located between the top substrate and the bottom substrate, and a plurality of the intermediate substrates of each part teeth Formed as opposing portions positioned opposite each other, the opposing portions have a joint portion provided with a plated portion and a non-joint portion not provided with the plated portion, the bottom substrate or the intermediate substrate has an injection groove that opens to the top substrate side and into which solder is injected, and the joint portions of adjacent intermediate substrates face each other. Furthermore, the joint portion is positioned continuously with the injection groove. In this state, the solder injected into the injection groove flows between the joints by capillary action when heated by reflow.

[0020] Thus, in the electronic device and the multi-stage substrate according to the present technology, the solder injected into the injection groove flows between the top substrate and the bottom substrate along the opposing joint portion by capillary action during heating, and the solder fills the entire gap of the joint portion.

Brief Description of the Drawings

[0021] [Figure 1] Figs. 2 to 32 show embodiments of the present technology, and this figure is a schematic exploded perspective view of an electronic device. [Figure 2] It is a schematic exploded perspective view of a multi-stage substrate. [Figure 3] It is a schematic perspective view of a multi-stage substrate. [Figure 4] It is a schematic plan view of an intermediate substrate. [Figure 5] It is a schematic cross-sectional view of an intermediate substrate. [Figure 6] It is a schematic plan view showing a part of the arrangement state of the intermediate substrate. [Figure 7] It is a schematic cross-sectional view showing a part of the multi-stage substrate. [Figure 8] It is an exploded perspective view showing parts of adjacent intermediate substrates and the bottom substrate. [Figure 9] It is a perspective view showing a state where adjacent intermediate substrates are arranged on the bottom substrate. [Figure 10] It is a plan view showing an injection groove. [Figure 11] It is a plan view showing a state where solder is injected into the injection groove. [Figure 12] It is a plan view showing a state where two intermediate substrates are arranged on the bottom substrate. [Figure 13] It is a cross-sectional view showing a state where the solder injected into the injection groove flows between joints. [Figure 14] It is a plan view showing an example where a non-joint portion is formed outside the intermediate substrate. [Figure 15] It is a cross-sectional view showing an example where a non-joint portion is formed outside the intermediate substrate. [Figure 16]This is a plan view showing an example in which injection grooves are formed in an intermediate substrate. [Figure 17] This is a cross-sectional view showing an example in which injection grooves are formed in an intermediate substrate. [Figure 18] This is a plan view showing an example of how electronic components are arranged in the space of an intermediate substrate. [Figure 19] This is a plan view showing the overall arrangement of electronic components in an example where electronic components are placed in the space of an intermediate substrate. [Figure 20] This is a front view showing the positioning electronic components in place. [Figure 21] This is a front view showing a static load applied to an example where electronic components are placed in the space of an intermediate substrate. [Figure 22] This diagram shows the state after side fill has been applied to the top circuit board, etc. [Figure 23] This is a plan view showing the original board for the top circuit board. [Figure 24] This diagram shows the state where side fill has been applied to the top substrate, etc., between the joints. [Figure 25] This is a perspective view showing an example in which a damming wall is provided on the intermediate substrate. [Figure 26] Figures 27 to 31, along with this figure, show the configuration of the first connection line for the differential signal circuit and the second connection line for the ground circuit. This figure is a plan view showing an example in which one connection conductor is used as the first connection line and at least one connection conductor is used as the second connection line on adjacent intermediate boards arranged in a horizontal orientation. [Figure 27] This is a plan view showing an example in which, in adjacent intermediate substrates arranged in a horizontal and vertical orientation, one connecting conductor in each is used as a first connecting line and at least one connecting conductor in each is used as a second connecting line. [Figure 28] This is a plan view showing another example in which, in adjacent intermediate substrates arranged in a horizontal and vertical orientation, one connecting conductor in each is used as a first connecting line and at least one connecting conductor in each is used as a second connecting line. [Figure 29]This is a plan view showing an example in which at least one connecting conductor is used as a second connecting line in adjacent intermediate substrates arranged in a horizontal orientation. [Figure 30] This is a plan view showing another example in which at least one connecting conductor is used as a second connecting line in adjacent intermediate substrates arranged in a horizontal orientation. [Figure 31] This is a plan view showing an example in which at least one connecting conductor is used as a second connecting line in adjacent intermediate substrates arranged in a horizontal and vertical orientation. [Figure 32] This is a block diagram of an electronic device. [Modes for carrying out the invention]

[0022] The following describes the configurations for implementing this technology, including electronic equipment and multi-stage circuit boards, with reference to the attached drawings.

[0023] The embodiments described below apply this technology to an imaging device in which a multi-stage circuit board formed by stack mounting of an intermediate circuit board called an interposer board is arranged. However, the scope of application of this technology is not limited to imaging devices. This technology can be widely applied to other electronic devices that have such a multi-stage circuit board arranged inside, such as mobile phones and audio devices.

[0024] The multi-stage circuit board has a top board, a bottom board, and an intermediate board, with the intermediate board mounted between the top board and the bottom board. In the following description, the top board side is considered the upper side and the bottom board side is considered the lower side, and the directions of front, back, up, down, left, and right are indicated accordingly. Note that the directions of front, back, up, down, left, and right shown below are for the convenience of explanation, and the implementation of this technology is not limited to these directions.

[0025] <Overall Configuration of Electronic Devices> First, let's describe the general configuration of the electronic device 100 (see Figure 1).

[0026] The electronic device (imaging device) 100 is configured with the necessary parts arranged inside and outside the outer casing 101.

[0027] The outer casing 101 has a front cabinet 102 and a rear cabinet 103. The front cabinet 102 is formed, for example, as a horizontally elongated box shape with an opening at the rear, and has an opening 102a at the front. A mount portion 105 for attaching and detaching interchangeable lenses is attached to the periphery of the opening 102a. The rear cabinet 103 is formed as a substantially flat plate shape facing in the front-to-back direction and is attached to the front cabinet 102 in a manner that closes the rear opening of the front cabinet 102.

[0028] Inside the outer casing 101, a bracket 104, which functions as a circuit board mounting member, is arranged. A multi-stage circuit board 1 is mounted on the bracket 104. The multi-stage circuit board 1 functions, for example, as a control board that controls various parts of the electronic device 100.

[0029] <Outline configuration of a multi-stage circuit board> Next, the general configuration of the multi-stage circuit board 1 located inside the electronic device 100 will be described (see Figures 2 to 7).

[0030] The multi-stage circuit board 1 has a top board 2, a bottom board 3, and multiple intermediate boards 4 (see Figures 2 and 3). The thickness of the top board 2 and bottom board 3 is thinner than the thickness of the intermediate boards 4, and the thickness of the intermediate boards 4 is, for example, about 2 mm.

[0031] The top substrate 2 has a rectangular substrate base 5 made of glass epoxy or alumina, and a plurality of electronic components 6 mounted on at least one surface in the thickness direction of the substrate base 5. The substrate base 5 is insulating, and a first circuit pattern (not shown) is formed on one or both surfaces in the thickness direction of the substrate base 5. The electronic components 6 are mounted in a state where they are joined to each part of the first circuit pattern by solder or the like.

[0032] The bottom substrate 3, like the top substrate 2, has a rectangular substrate base 7 made of glass epoxy, alumina, or the like, and a plurality of electronic components 8 mounted on at least one surface in the thickness direction of the substrate base 7. The substrate base 7 is insulating, and a second circuit pattern (not shown) is formed on one or both surfaces in the thickness direction of the substrate base 7. The electronic components 8 are mounted in a state where they are joined to each part of the second circuit pattern by solder or the like.

[0033] Furthermore, the top board 2 and the bottom board 3 may have the same external dimensions or different dimensions. If they are different dimensions, for example, the bottom board 3 is slightly larger than the top board 2. However, the top board 2 may also be slightly larger than the bottom board 3.

[0034] The intermediate substrate 4 is formed in a strip (rectangular) shape and has an insulating base material 9 and a plurality of connecting conductors 10 extending in the thickness direction (up and down direction) of the base material 9 (see Figures 4 and 5). The connecting conductors 10 have both end faces formed as a first connecting surface 10a and a second connecting surface 10b, respectively, and the first connecting surface 10a and the second connecting surface 10b are exposed on both sides (upper and lower sides) in the thickness direction of the base material 9. When viewed from the thickness direction, the plurality of connecting conductors 10 on the intermediate substrate 4 are arranged in a staggered pattern (see Figure 4). The connecting conductors 10 function as connecting lines for various circuits formed on the top substrate 2 and the bottom substrate 3.

[0035] Multiple intermediate substrates 4 are positioned at predetermined intervals around the bottom substrate 3 in the circumferential direction, and are arranged in a frame-like shape overall (see Figures 2 and 3). The upper surfaces of the multiple intermediate substrates 4 are bonded to the top substrate 2 and the lower surfaces are bonded to the bottom substrate 3, and are positioned between the top substrate 2 and the bottom substrate 3.

[0036] For example, eight intermediate substrates 4 are provided and bonded to the outer periphery of the bottom substrate 3. The multiple intermediate substrates 4 are arranged in a point-symmetrical manner with respect to the bottom substrate 3 and the top substrate 2. Two adjacent intermediate substrates 4 have parts of their outer periphery (outer surface) facing each other, and each of these opposing parts is formed as an opposing part 11 (see Figure 6). Two opposing parts 11 are formed on a single intermediate substrate 4.

[0037] In the intermediate substrate 4, the opposing portion with respect to an adjacent intermediate substrate 4 changes depending on the orientation and position in which it is joined to the bottom substrate 3. Therefore, there are two types of intermediate substrate 4: one in which both ends (end faces) in the longitudinal direction are formed as two opposing portions 11, and another in which one end in the longitudinal direction and the portion continuous with this end are formed as two opposing portions 11.

[0038] As described later, solder is filled into the gaps between adjacent intermediate boards 4, and the adjacent intermediate boards 4 are joined together by solder. Therefore, in the multi-stage board 1, solder is filled into the gaps between all the intermediate boards 4 and all the adjacent intermediate boards 4 are joined together to form a frame-like structure, thereby improving the strength against impacts that occur when the multi-stage board 1 is dropped or otherwise subjected to.

[0039] Furthermore, in the multi-stage circuit board 1, components such as media slots (card slots) may be connected to the top circuit board 2 or the bottom circuit board 3.

[0040] In the multi-stage circuit board 1, the intermediate board 4 is connected to the terminal portion 2a of the top board 2 by a bump 30 at the first connection surface 10a of the connecting conductor 10 (see Figure 7). The terminal portion 2a is part of the first circuit pattern, and the bump 30 is formed, for example, by solder. The intermediate board 4 is also connected to the terminal portion 3a of the bottom board 3 by a bump 40 at the second connection surface 10b of the connecting conductor 10 (see Figure 7). The terminal portion 3a is part of the second circuit pattern, and the bump 40 is formed, for example, by solder.

[0041] <Bonding of intermediate substrates> Next, we will explain the bonding of adjacent intermediate substrates 4 (see Figures 8 to 17).

[0042] As described above, in the multi-stage substrate 1, solder is injected into the gaps between all the intermediate substrates 4, joining all adjacent intermediate substrates 4 together to form a frame-like structure. Although adjacent intermediate substrates 4 are joined at their opposing portions 11, the following explanation will describe the case where opposing portions 11 formed at the longitudinal ends of the intermediate substrates 4 are joined as an example.

[0043] In the multi-stage substrate 1, injection grooves 12 are formed in the bottom substrate 3 as a structure for joining adjacent intermediate substrates 4 (see Figures 8 to 10).

[0044] The injection groove 12 opens on the top substrate 2 side (upper side) and has, for example, a plurality of alternately formed connection portions 13 and a plurality of non-connection portions 14. Alternatively, the injection groove 12 may have one connection portion 13 and a plurality of non-connection portions 14.

[0045] The connecting portion 13 is formed in the shape of a narrow slit with a width H1, and the non-connecting portion 14 has a width H2 that is larger than the width H1 of the connecting portion 13, for example, both sides in the width direction are formed in a curved shape. The connecting portion 13 has two opposing sides 13a in the width direction, and a conductive portion 15 such as copper foil is provided on the bottom surface of the connecting portion 13, and the conductive portion 15 is provided, for example, as part of a second circuit pattern. The surface 15a of the conductive portion 15 is located below the upper edge of the side surface 13a. The non-connecting portion 14 has two opposing circumferential surfaces 14a and a bottom surface 14b, and the non-connecting portion 14 does not have a conductive portion 15, and therefore the bottom surface 14b of the non-connecting portion 14 is located below the surface 15a of the conductive portion 15. The non-connecting portion 14 is the part from which the resist has been removed. In the injection groove 12, the volume of the non-connecting portion 14 is larger than the volume of the connecting portion 13.

[0046] Furthermore, in the multi-stage substrate 1, a joint portion 11a and a non-joined portion 11b are formed on the opposing portion 11 of the intermediate substrate 4 as a structure for joining adjacent intermediate substrates 4.

[0047] The joint portion 11a is formed in a planar shape and is provided with a plated portion 16 such as copper foil. The non-joint portion 11b is formed in a concave shape with an opening to the side, and its surface is curved, for example, the same size and shape as the circumferential surface 14a. The non-joint portion 11b is the part from which the resist has been removed. The joint portion 11a and the non-joint portion 11b are formed alternately in the same number as the connecting portion 13 and the non-connecting portion 14.

[0048] In the longitudinal direction of the injection groove 12 and the longitudinal direction of the opposing portion 11, the length of the joint portion 11a is the same as the length of the connecting portion 13, and the length of the non-jointed portion 11b is the same as the length of the non-connecting portion 14.

[0049] When adjacent intermediate substrates 4 are joined, solder 50 is injected into the injection groove 12 (see Figure 11), the adjacent intermediate substrates 4 are placed on either side of the injection groove 12 (see Figure 12), and the top substrate 2 is placed on the intermediate substrates 4. Since the volume of the non-connection portion 14 of the injection groove 12 is larger than the volume of the connection portion 13, the amount of solder 50 injected into the non-connection portion 14 is greater than the amount of solder 50 injected into the connection portion 13.

[0050] When adjacent intermediate substrates 4 are arranged on either side of the injection groove 12, the surface of the non-joint portion 11b is positioned directly above the circumferential surface 14a of the non-connected portion 14. Therefore, a space 17 is formed between adjacent intermediate substrates 4 by the non-connected portion 14 and the two non-joint portions 11b.

[0051] Furthermore, when adjacent intermediate substrates 4 are arranged on either side of the injection groove 12, the plated portion 16 is positioned directly above the conductive portion 15. In this case, the distance between the surfaces 16a of the plated portion 16 on adjacent intermediate substrates 4 is smaller than the distance between the sides 13a of the connection portion 13, and the distance L between the surfaces 16a is, for example, about 0.5 mm.

[0052] As described above, when solder 50 is injected into the injection groove 12, and adjacent intermediate substrates 4 are arranged on both sides of the injection groove 12, and the top substrate 2 is placed on the intermediate substrates 4, reflow is performed and the solder 50 is heated.

[0053] The heated solder 50 melts, and because the distance L between the surfaces 16a is small, the molten solder 50 is drawn up between the joints 11a by capillary action and flows to the top substrate 2 (see Figure 13). When the reflow is complete, the solder 50 that has flowed between the joints 11a to the top substrate 2 solidifies, and the adjacent intermediate substrates 4 are joined by the solder 50.

[0054] In this state, with the joint portions 11a of adjacent intermediate substrates 4 facing each other, the solder 50 injected into the injection groove 12 flows between the joint portions 11a by capillary action during heating by reflow soldering, filling the entire space between the joint portions 11a, and the adjacent intermediate substrates 4 are joined by the filled and solidified solder 50.

[0055] As a result, even when multiple intermediate substrates 4 formed in a strip shape are used, high overall bonding strength of the intermediate substrates 4 is ensured, as well as high bonding strength between the top substrate 2 and the intermediate substrate 4, and between the bottom substrate 3 and the intermediate substrate 4. Furthermore, since the solder 50 injected into the injection groove 12 is drawn up by capillary action and filled between the joint portions 11a, the solder 50 does not get between the top substrate 2 and the intermediate substrate 4, or between the bottom substrate 3 and the intermediate substrate 4, and the solder 50 does not adhere to the connecting conductor 10.

[0056] Therefore, high bonding strength between adjacent intermediate substrates 4 can be ensured without impairing the functionality of the multi-stage substrate 1.

[0057] Furthermore, the opposing portion 11 has a joint portion 11a provided with a plated portion 16 and a non-joint portion 11b not provided with a plated portion 16, and the injection groove 12 has a connecting portion 13 formed in the bottom substrate 3 and provided with a conductive portion 15 and a non-connecting portion 14 not provided with a conductive portion 15, and intermediate substrates 4 are positioned on both sides of the injection groove 12, and solder 50 flows between the joint portions 11a by capillary action when the joint portions 11a and non-joint portions 11b face each other.

[0058] Therefore, when the solder 50 injected into the injection groove 12 flows between the joint portions 11a, a space 17 exists between the non-joint portions 11b. As the solder 50 flows between the joint portions 11a, the air contained in the solder 50 is released into the space 17, making it difficult for voids to form inside the solder 50 and ensuring a good bonding state between the intermediate substrates 4.

[0059] Furthermore, multiple joints 11a and non-joints 11b, and connecting portions 13 and non-connecting portions 14 are formed, with joints 11a and non-joints 11b being formed alternately, and connecting portions 13 and non-connecting portions 14 being formed alternately.

[0060] Therefore, as multiple connection points 13 and non-connection points 14 are formed, the amount of solder 50 injected increases, and as multiple joint points 11a and non-joining points 11b are formed alternately, adjacent intermediate substrates 4 are joined by solder 50 at multiple joint points 11a on both sides of the non-joining points 11b, thus ensuring even higher bonding strength between the intermediate substrates 4.

[0061] Furthermore, the volume of the non-connecting portion 14 is larger than the volume of the connecting portion 13.

[0062] Therefore, it becomes possible to increase the amount of solder 50 injected into the non-connected portion 14, and the space 17 between the two non-connected portions 11b becomes a larger space. As a result, a sufficient amount of solder 50 flows between the opposing plated portions 16, and the air contained in the solder 50 is sufficiently released into the space 17, thereby ensuring an even higher bonding strength between the intermediate substrates 4.

[0063] In addition, the above example shows an example where the injection groove 12 has a connecting portion 13 and a non-connecting portion 14 between adjacent intermediate substrates 4. However, it is also possible to configure it so that the non-connecting portion 14 of the injection groove 12 is located on the outside between adjacent intermediate substrates 4 (see Figures 14 and 15).

[0064] The injection groove 12 is composed of one connecting portion 13 and two non-connecting portions 14, with the non-connecting portions 14 being formed continuously on both sides of the non-connecting portion 13. In this case, the opposing portion 11 of the intermediate substrate 4 is formed only by the joining portion 11a.

[0065] In this configuration, during reflow, solder 50 is mainly drawn up between the joints 11a by capillary action from the non-connection parts 14 located on both sides of the connection part 13 and flows to the top substrate 2.

[0066] In the configuration described above, where the non-connecting portion 14 is located on the outside of the intermediate substrate 4, solder 50 can be injected from the outside of the intermediate substrate 4. This allows solder 50 to be easily injected into the injection groove 12 even when the intermediate substrate 4 is placed adjacent to the bottom substrate 3, thus facilitating the manufacturing of the multi-stage substrate 1.

[0067] Furthermore, in a configuration where the non-connected portion 14 of the injection groove 12 exists on the outside of the intermediate substrate 4, the entire opposing portion 11 is formed as a joint portion 11a, so the entire opposing portions 11 are joined together by solder 50, ensuring a strong bond between the intermediate substrates 4.

[0068] Furthermore, although the above example shows an injection groove 12 formed in the bottom substrate 3, for example, an injection groove 12A may be formed in the intermediate substrate 4 instead of the injection groove 12 (see Figures 16 and 17).

[0069] The injection groove 12A is formed at the upper end of adjacent portions of adjacent intermediate substrates 4, and is shaped to open to the top substrate 2 side (upper side) and to the sides facing each other. In such a configuration, it is desirable that a recess 18 is formed on the lower surface side of the top substrate 2 directly above the injection groove 12A.

[0070] In this configuration, solder 50 is injected into the injection groove 12A, and the top substrate 2 is placed on the intermediate substrate 4 with the solder 50 injected into the injection groove 12A.

[0071] During reflow soldering, the solder 50 injected into the injection groove 12A flows through the joint 11a to the bottom substrate 3 by capillary action. At this time, the solder 50 also flows toward the bottom substrate 3 by its own weight, ensuring high fluidity of the solder 50. Furthermore, because a recess 18 is formed in the top substrate 2, when the solder 50 injected into the injection groove 12A melts and flows, the solder 50 is retained in the recess 18, preventing the solder 50 from flowing toward the terminal portion 2a. Therefore, the solder 50 does not come into contact with the terminal portion 2a, preventing the occurrence of a short circuit caused by the solder 50. In addition, because the solder 50 is injected into the injection groove 12A which is open upwards, the solder 50 does not flow toward the connecting conductor 10, preventing the occurrence of a short circuit.

[0072] <Joining the top, middle, and bottom substrates> Next, we will explain the bonding of the top substrate 2, the intermediate substrate 4, and the bottom substrate 3 (see Figures 18 to 25).

[0073] As described above, in the multi-stage substrate 1, the connecting conductor 10 of the intermediate substrate 4 is joined to the first circuit pattern of the top substrate 2 and the second circuit pattern of the bottom substrate 3, and these joining is performed via bumps 30 and 40. When joining, multiple intermediate substrates 4 are arranged on the bottom substrate 3 in a frame-like shape as a whole, and the top substrate 2 is placed on the intermediate substrates 4. At this time, the top substrate 2 is prone to warping, with the central part being displaced downwards. If warping occurs, the bumps 30 may lift up from the intermediate substrate 4, or the top substrate 2 may lift up from the bumps 30, making it impossible to ensure a good bond between the top substrate 2 and the intermediate substrate 3.

[0074] Therefore, in order to prevent warping of the top substrate 2 during bonding, a weight is placed on top of the top substrate 2, and the weight applies a downward static load to the upper part of the intermediate substrate 4 on the top substrate 2.

[0075] In this case, the application of a static load may cause excessive deformation of the bump 40 located between the intermediate substrate 4 and the bottom substrate 3. Therefore, a spacer may be placed between the intermediate substrate 4 and the bottom substrate 3 to prevent excessive deformation of the bump 40.

[0076] However, depending on the position of the spacers, the intermediate board 4 may tilt relative to the bottom board 3, which could prevent the bumps 40 from ensuring a good bond between the intermediate board 4 and the bottom board 3.

[0077] Therefore, in the multi-stage substrate 1, the tilt of the intermediate substrate 4 relative to the bottom substrate 3 is prevented by the following configuration (see Figures 18 to 21).

[0078] As described above, the intermediate substrate 4 has multiple connecting conductors 10 arranged in a staggered pattern when viewed from the thickness direction. This staggered arrangement of the connecting conductors 10 of the intermediate substrate 4 creates spaces 4a at diagonal corners where no connecting conductors 10 are present (see Figure 18).

[0079] Multiple intermediate substrates 4, each with connecting conductors 10 arranged in a staggered pattern, are positioned on the bottom substrate 3, spaced apart in the circumferential direction of the bottom substrate 3, when joining the top substrate 2 and the bottom substrate 3 is performed, and are arranged as a frame (see Figure 19). The top substrate 2 is placed on the multiple intermediate substrates 4.

[0080] At this time, an electronic component 19 that functions as a spacer is placed in the space 4a between the bottom substrate 3 and the intermediate substrate 4, without contacting the connecting conductor 10 (see Figures 18 and 19). The electronic component 19 is placed in an area where the second circuit pattern is not formed and is not used as an electronic component on the circuit. Therefore, an inexpensive type such as a resistor can be used as the electronic component 19. The electronic component 19 is fixed to at least one of the upper surface of the bottom substrate 3 or the space 4a of the intermediate substrate 4 by means of adhesive, for example.

[0081] In this way, the electronic components 19 are arranged in the space 4a of the intermediate substrate 4, but all the intermediate substrates 4 are arranged on the bottom substrate 3 such that the electronic components 19 arranged sequentially in the circumferential direction of the bottom substrate 3 are positioned alternately on the outside and inside. Specifically, as shown in Figure 19, when the electronic components 19 are numbered P1, P2, P3, ... in order in the circumferential direction of the bottom substrate 3, the odd-numbered P1, P3, P5, ... are arranged on the outside of the intermediate substrate 4, and the even-numbered P2, P4, P6, ... are arranged on the inside of the intermediate substrate 4.

[0082] Furthermore, when multiple intermediate substrates 4 are arranged in a frame-like shape as a whole, two electronic components 19 located diagonally opposite each other in the overall shape are provided as positioning electronic components 19A and are taller than the other electronic components 19, and insertion recesses 20 are formed in the space 4a where the positioning electronic components 19A are placed (see Figure 20). The portion of the intermediate substrate 4 where the insertion recesses 20 are formed is the portion from which the resist has been removed.

[0083] The insertion recess 20 and the positioning electronic component 19A function as positioning parts when the intermediate board 4 is placed on the bottom board 3. The intermediate board 4 is positioned relative to the bottom board 3 by inserting a portion of the positioning electronic component 19A into the insertion recess 20. When the intermediate board 4 is bonded to the top board 2, the top board 2 is positioned relative to the bottom board 3. The upper surface of the positioning electronic component 19A, which is partially inserted into the insertion recess 20, does not come into contact with the top board 2, while the other electronic components 19, other than the positioning electronic component 19A, come into contact with the lower surface of the top board 2.

[0084] As described above, with the electronic components 19 arranged in the space 4a of the intermediate substrate 4 and the electronic components 19 arranged sequentially in the circumferential direction of the bottom substrate 3 alternately positioned on the outside and inside, the top substrate 2 is placed on multiple intermediate substrates 4, and when the connecting conductors 10 of the intermediate substrates 4 are joined to the first circuit pattern of the top substrate 2 and the second circuit pattern of the bottom substrate 3, a weight (not shown) is placed on top of the top substrate 2 from above. The weight applies a downward static load F to the upper part of the intermediate substrates 4 on the top substrate 2 (see Figure 21). Therefore, warping of the top substrate 2 is prevented.

[0085] As described above, the electronic components 19 are placed in the space 4a of the intermediate substrate 4, and the electronic components 19 arranged sequentially in the circumferential direction of the bottom substrate 3 are positioned alternately on the outside and inside. This increases the distance between the electronic components 19 arranged sequentially in the circumferential direction of the bottom substrate 3, and ensures a good balance in the placement of the electronic components 19 as a whole across the multiple intermediate substrates 4.

[0086] Therefore, when a static load F is applied to the top substrate 2 toward the bottom substrate 3, tilting of the intermediate substrate 4 relative to the bottom substrate 3 is less likely to occur, preventing warping of the top substrate 2 relative to the bottom substrate 3, and suppressing deformation of the bump 40, thereby ensuring a stable connection between the connecting conductor 10 of the intermediate substrate 4 and the second circuit pattern of the bottom substrate 3.

[0087] Furthermore, two positioning electronic components 19A are provided, which are the furthest apart from the other electronic components 19. The height of the positioning electronic components 19A is made higher than the height of the other electronic components 19, and an insertion recess 20 is formed in the portion of the intermediate substrate 4 where the positioning electronic components 19A are placed, into which a part of the positioning electronic components 19A is inserted.

[0088] As a result, when multiple intermediate substrates 4 are bonded to the top substrate 2 and the intermediate substrates 4 are bonded to the bottom substrate 3, the positioning electronic component 19A and the insertion recess 20 position the intermediate substrates 4 relative to the bottom substrate 3. Therefore, the position of the top substrate 2 relative to the bottom substrate 3 can be determined without providing a dedicated positioning means, and high positional accuracy of the top substrate 2 relative to the bottom substrate 3 can be ensured without increasing manufacturing costs.

[0089] Furthermore, by using an intermediate substrate 4 in which the connecting conductors 10 are arranged in a staggered pattern, it is possible to form spaces 4a at diagonal corners without reducing the number of connecting conductors 10, compared to, for example, using an intermediate substrate with a square arrangement in which the connecting conductors 10 are formed in a vertical and horizontal line.

[0090] <Bonding the intermediate substrate to the top and bottom substrates> Next, we will explain how the intermediate substrate 4 is bonded to the top substrate 2 and the bottom substrate 3 (see Figures 22 to 25).

[0091] As described above, the intermediate substrate 4 is joined to the first circuit pattern of the top substrate 2 and the second circuit pattern of the bottom substrate 3 via bumps 30 and 40, respectively, by connecting conductors 10. After the intermediate substrate 4 is joined to the top substrate 2 and the bottom substrate 3, adhesive is applied to the bottom substrate 3 and the intermediate substrate 4, and to the top substrate 2 and the intermediate substrate 4, in order to increase the fixing strength of the intermediate substrate 4 to the top substrate 2 and the bottom substrate 3 (see Figure 22).

[0092] The bonding process is carried out using dispenser 200. For example, the bonding process is performed with dispenser 200 positioned vertically to improve work efficiency. In this case, the sizes of the bottom substrate 3, intermediate substrate 4, and top substrate 2 are determined so that their outer shapes become progressively smaller, and the bonding process is carried out with steps formed between the bottom substrate 3 and intermediate substrate 4, and between the intermediate substrate 4 and top substrate 2.

[0093] During the bonding process between the top substrate 2 and the multiple intermediate substrates 4, there is a possibility that gaps may exist between adjacent intermediate substrates 4, and the adhesive side fill 300 may flow into these gaps. In this case, the side fill 300 that has flowed down may flow into the inside of the intermediate substrates 4 which are formed into a frame shape, and adhere to the electronic components 8 mounted on the bottom substrate 3 or the second circuit pattern on the bottom substrate 3, potentially causing a short circuit.

[0094] Therefore, in order to prevent Sidefill 300 from flowing into gaps, adhesive is sometimes applied in a way that avoids applying Sidefill 300 to areas where gaps exist.

[0095] However, in this case, the bonding area of ​​the side fill 300 to the top substrate 2 and the intermediate substrate 4 will be reduced, which may decrease the fixing strength of the intermediate substrate 4 to the top substrate 2.

[0096] Therefore, in the multi-stage substrate 1, the fixing strength of the intermediate substrate 4 to the top substrate 2 is improved by the following configuration.

[0097] The top substrate 2 is formed by cutting out a portion of the original plate 400 (see Figure 23). Figure 23 shows the portion of the original plate 400 that will be formed as the top substrate 2 with a textured surface.

[0098] Multiple top substrates 2 can be formed by cutting them out from the original plate 400, and the top substrates 2 are formed by cutting at multiple joints 21. The joints 21 protrude outward from the outer periphery of the top substrate 2 and are spaced apart in the circumferential direction. The joints 21 are the parts that connect the top substrate 2 to the parts of the original plate 400 other than the parts that are provided as top substrates 2, and slits 400a are formed in the parts of the original plate 400 between the joints 21.

[0099] The top substrate 2 is formed by cutting away the intermediate portion 21a of the joint 21, leaving at least a portion of the joint 21 intact. The top substrate 2 has multiple joints 21 at positions that coincide with the gaps between multiple intermediate substrates 4.

[0100] The bottom board 3, intermediate board 4, and top board 2 are sized such that their outer dimensions decrease in order, and steps are formed between the bottom board 3 and intermediate board 4, and between the intermediate board 4 and top board 2 (see Figure 24). In this way, the positions of the multiple joints 21 on the top board 2 coincide with the positions of the gaps in the multiple intermediate boards 4, so that each joint 21 is aligned with the gap in the intermediate board 4, and each joint 21 covers the gap in the intermediate board 4.

[0101] The side fill 300 is applied to the upper surface of the intermediate substrate 4 and between the joints 21 on the outer periphery of the top substrate 2, and multiple intermediate substrates 4 are fixed to the top substrate 2 by the side fill 300. Since the side fill 300 is applied between the joints 21, a portion of the side fill 300 is bonded to both sides of the joints 21.

[0102] Furthermore, since the side fill 300 is applied between the joints 21, the side fill 300 does not flow into the gaps between adjacent intermediate substrates 4. Therefore, the joints 21 function as damming protrusions that block the flow of the side fill 300.

[0103] On the other hand, the side fill 300 applied to the outer circumference of the intermediate substrate 4 on the upper surface of the bottom substrate 3 is applied to the entire circumference of the outer circumference of the multiple intermediate substrates 4, and all of the intermediate substrates 4 are fixed to the bottom substrate 3.

[0104] Furthermore, when the side fill 300 is applied to the outer periphery of the top substrate 2, there is a possibility that the side fill 300 may flow down at the four corners of the multiple intermediate substrates 4 which are formed in a frame shape as a whole. Therefore, it is desirable that a damming wall portion 22 be provided at each of these four corners (see Figure 25). The damming wall portion 22 is formed, for example, by two orthogonal parts according to the shape of the corner.

[0105] In this way, since damming walls 22 are provided at each of the four corners to block the side fill 300, the side fill 300 is blocked by the damming walls 22 at the four corners, preventing liquid from dripping from the corners towards the bottom substrate 3, and ensuring a proper bonding state of the intermediate substrate 4 to the top substrate 2.

[0106] Furthermore, it is desirable that the damming wall portion 22 be formed from the same material as the base material 9 of the intermediate substrate 4. This makes it possible to form the damming wall portion 22 during the processing of the base material 9, thereby reducing manufacturing costs and preventing the side fill 300 from dripping from the corners towards the bottom substrate 3.

[0107] Furthermore, in the multi-stage substrate 1, damming walls may also be provided at the corners of the bottom substrate 3 to block the side fill 300 applied to the outer circumference of the bottom substrate 3. In this case, it is desirable that the damming walls be made of the same material as the base material 7 of the bottom substrate 3.

[0108] As described above, the top substrate 2 is provided with a plurality of damming protrusions on its outer periphery that protrude outward and are spaced apart in the circumferential direction, and the plurality of intermediate substrates 4 are joined to the top substrate 2 with the gaps between each intermediate substrate 4 covered by the damming protrusions.

[0109] Therefore, since the gaps in the intermediate substrate 4 are covered by the damming protrusions, when joining the top substrate 2 and the multiple intermediate substrates 4 with the side fill 300, it is possible to prevent the side fill 300 from dripping onto the bottom substrate 3. In addition, since the side fill 300 is joined to the damming protrusions, it is possible to ensure a proper bonding state of the intermediate substrate 4 to the top substrate 2 while ensuring high bonding strength.

[0110] Furthermore, the substrate base 5 of the top substrate 2 is formed by cutting the portion where multiple joints 21 are connected in the original plate 400 at the intermediate portion 21a of the joints 21, and the joints 21 are used as damming protrusions.

[0111] Therefore, there is no need to form a damming projection using a dedicated process, which reduces manufacturing costs while ensuring proper bonding of the intermediate substrate 4 to the top substrate 2, and also ensures high bonding strength.

[0112] <Relationship between circuit connection wires and intermediate boards> Next, the relationship between the connecting conductor 10, which functions as a connecting wire for the circuit, and the intermediate substrate 4 will be explained (see Figures 26 to 31).

[0113] In the multi-stage circuit board 1, as described above, multiple intermediate circuit boards 4 are used, and multiple connecting conductors 10 are formed on the intermediate circuit boards 4. The connecting conductors 10 function as connecting lines for various circuits formed on the top circuit board 2 and the bottom circuit board 3.

[0114] A differential signal circuit is formed on the multi-stage board 1 as a high-speed signal circuit. However, because a differential signal circuit is a high-speed signal circuit, impedance management and noise countermeasures are necessary when wiring it through the connecting conductor 10 of the intermediate board 4. In particular, since the intermediate board 4 is thick, about 2 mm, noise is easily generated, and sufficient noise countermeasures must be implemented.

[0115] Therefore, on the intermediate substrate 4, multiple connection lines for the grounding circuit are formed surrounding the pair of connection lines for the differential signal circuit, and noise generation is suppressed by surrounding the connection lines for the differential signal circuit with multiple connection lines for the grounding circuit.

[0116] However, depending on the relationship between the number of connecting conductors 10 on the intermediate substrate 4 and the number of connecting conductors 10 used as connecting lines for the grounding circuit, there is a possibility that some connecting conductors 10 may not be used as connecting lines. If there are many connecting conductors 10 that are not used as connecting lines, it becomes impossible to efficiently form a differential signal circuit.

[0117] Therefore, in the multi-stage circuit board 1, the connecting conductor 10 is configured to be used efficiently by the following means.

[0118] In the intermediate substrate 4, two adjacent connecting conductors 10 are used as the first connecting line 10X, which is a pair of signals (pair signals) for the differential signal circuit, and eight connecting conductors 10, for example, that surround the first connecting line 10X are used as the second connecting line 10Y for the ground circuit (see Figure 26). The second connecting line 10Y for the ground circuit is partially shared. For the sake of ease of understanding, in each figure from Figure 26 onward, the first connecting line 10X is shown as a black circle, and the second connecting line 10Y surrounding the two first connecting lines 10X is shown connected by a dashed line.

[0119] Furthermore, in the intermediate substrate 4, two connecting conductors 10 positioned side by side on adjacent intermediate substrates 4 are used as first connecting lines 10X. Therefore, one connecting conductor 10 on each of the adjacent intermediate substrates 4 is used as one first connecting line 10X and the other first connecting line 10X. In this configuration, for example, three connecting conductors 10 on each of the adjacent intermediate substrates 4 are used as second connecting lines 10Y. In this case, there may be a shortage of second connecting lines 10Y, so in such cases, solder 50 that has flowed and solidified by capillary action between opposing joints 11a on adjacent intermediate substrates 4 is used as the second connecting line 10Y. The solder 50 that has flowed and solidified between the joints 11a is connected to the first circuit pattern on the top substrate 2 and the second circuit pattern on the bottom substrate 3, and these first and second circuit patterns are connected to the ground circuit.

[0120] In this way, in the intermediate substrate 4, the missing second connecting wire 10Y is compensated for by the solder 50 that has flowed and solidified between the joints 11a.

[0121] In the configuration described above, where the connecting conductors 10 of adjacent intermediate substrates 4 are each used as first connecting lines 10X and each connecting conductor 10 of adjacent intermediate substrates 4 is each used as a second connecting line 10Y, there are various embodiments as follows (see Figures 27 and 28). In each of the following embodiments, if the number of second connecting lines 10Y is insufficient, the solder 50 that has flowed and solidified between the joints 11a by capillary action is used as the second connecting line 10Y, as described above.

[0122] In a first embodiment, in an intermediate substrate 4 arranged horizontally and an intermediate substrate 4 arranged vertically, one connecting conductor 10 is used as a first connecting line 10X and at least one connecting conductor 10 is used as a second connecting line 10Y (see Figure 28). In this case, for example, in adjacent intermediate substrates 4, three connecting conductors 10 are used as second connecting lines 10Y, and the shape formed by connecting all the second connecting lines 10Y is a horizontal shape.

[0123] In a second embodiment, in an intermediate substrate 4 arranged horizontally and an intermediate substrate 4 arranged vertically, one connecting conductor 10 is used as a first connecting line 10X and at least one connecting conductor 10 is used as a second connecting line 10Y (see Figure 27). In this case, for example, in adjacent intermediate substrates 4, three connecting conductors 10 are used as second connecting lines 10Y, and the shape formed by connecting all the second connecting lines 10Y is a vertical shape.

[0124] As described above, in the multi-stage board 1, one pair of first connecting lines 10X is provided on each of the two adjacent intermediate boards 4, and at least one of the multiple second connecting lines 10Y is provided on each of the two adjacent intermediate boards 4.

[0125] Therefore, since the connecting conductors 10 of adjacent intermediate boards 4 are used as the first connecting line 10X and the second connecting line 10Y, respectively, the connecting conductors 10 can be effectively utilized, enabling efficient wiring of the differential signal circuit.

[0126] Furthermore, efficient wiring makes it possible to reduce the number of unused connecting conductors 10, which in turn makes it possible to reduce the number of intermediate boards 4 or the size of the intermediate boards 4, thereby miniaturizing the multi-stage board 1.

[0127] Furthermore, the solder 50 that has flowed between the joints 11a of the two intermediate substrates 4 is used as a second connecting line 10Y in a solidified state.

[0128] Therefore, since the solder 50 that flows between the joints 11a is used as the second connecting line 10Y for the differential signal circuit, the solder 50 can be used effectively, and the differential signal circuit can be wired more efficiently.

[0129] Furthermore, in the multi-stage board 1, it is also possible to configure it so that one connecting conductor 10 of one intermediate board 4 is used as the first connecting line 10X, and each connecting conductor 10 of adjacent intermediate boards 4 is used as the second connecting line 10Y (see Figures 29 to 31).

[0130] For example, in adjacent intermediate boards 4 arranged in a horizontal orientation, the connecting conductor 10 of one intermediate board 4 may be used as the first connecting line 10X, and at least one connecting conductor 10 of each adjacent intermediate board 4 may be used as the second connecting line 10Y (see Figures 29 and 30). In this case, for example, five connecting conductors 10 may be used as the second connecting line 10Y on one intermediate board 4 and three connecting conductors 10 may be used as the second connecting line 10Y on the other intermediate board 4 (see Figure 29), or seven connecting conductors 10 may be used as the second connecting line 10Y on one intermediate board 4 and one connecting conductor 10 may be used as the second connecting line 10Y on the other intermediate board 4 (see Figure 30).

[0131] Furthermore, for example, in an intermediate substrate 4 arranged horizontally and an intermediate substrate 4 arranged vertically, the connecting conductor 10 of one intermediate substrate 4 may be used as the first connecting line 10X, and at least one connecting conductor 10 of each adjacent intermediate substrate 4 may be used as the second connecting line 10Y (see Figure 31). In this case, for example, five connecting conductors 10 on one intermediate substrate 4 are used as the second connecting line 10Y, and three connecting conductors 10 on the other intermediate substrate 4 are used as the second connecting line 10Y.

[0132] <An embodiment of an electronic device> The following describes an example configuration of an imaging device to which this technology applies as electronic equipment (see Figure 32).

[0133] The electronic device (imaging device) 100 is equipped with, for example, an interchangeable lens having a camera block 90 that performs the imaging function. Furthermore, if the electronic device 100 has a lens barrel, the camera block 90 is provided on the electronic device 100.

[0134] The electronic device 100 includes a camera signal processing unit 91 that performs signal processing such as analog-to-digital conversion of captured image signals, and an image processing unit 92 that performs recording and playback processing of image signals. The electronic device 100 also includes a display unit 93 that displays captured images, an R / W (reader / writer) 94 that writes and reads image signals to and from memory 99, a CPU (Central Processing Unit) 95 that controls the entire electronic device 100, a lens drive control unit 96 that controls the driving of the lens located in the camera block 90, and an operation unit 97 that allows the user to perform the required operations, such as various switches.

[0135] The electronic device 100 is equipped with an image sensor 98, such as a CCD or CMOS, which converts the optical image captured by the camera block 90 into an electrical signal.

[0136] The camera signal processing unit 91 performs various signal processing on the output signal from the image sensor 98, including conversion to a digital signal, noise reduction, image quality correction, and conversion to luminance and chromatic difference signals.

[0137] The image processing unit 92 performs compression coding, decompression and decoding of image signals based on a predetermined image data format, as well as conversion processing of data specifications such as resolution.

[0138] The display unit 93 has the function of displaying various data such as the user's operation status to the control unit 97 and captured images. In addition, the electronic device 100 does not necessarily have to have a display unit 93, and may be configured to send captured image data to another display device and display the image.

[0139] The R / W94 writes image data encoded by the image processing unit 92 to the memory 99 and reads image data recorded in the memory 99.

[0140] The CPU 95 functions as a control processing unit that controls each circuit block provided in the electronic device 100, and controls each circuit block based on instruction input signals from the operation unit 97, etc.

[0141] The lens drive control unit 96 controls the drive source that moves the lens based on the control signal from the CPU 95.

[0142] The control unit 97 outputs instruction input signals to the CPU 95 in response to user operations.

[0143] Memory 99 is, for example, a removable semiconductor memory that can be attached to a slot connected to R / W 94, or a semiconductor memory that is pre-built inside the electronic device 100.

[0144] The operation of the electronic device 100 is described below.

[0145] In the standby state for shooting, under the control of the CPU 95, the captured image signal is output to the display unit 93 via the camera signal processing unit 91 and displayed as a camera-through image. Also, when an instruction input signal is received from the operation unit 97, the CPU 95 outputs a control signal to the lens drive control unit 96, and the lens is moved based on the control of the lens drive control unit 96.

[0146] When a shooting operation is performed in response to an instruction input signal from the control unit 97, the captured image signal is output from the camera signal processing unit 91 to the image processing unit 92, where it is compressed and encoded, and converted into digital data in a predetermined data format. The converted data is output to the R / W 94 and written to the memory 99.

[0147] When playing back image data recorded in memory 99, in response to an operation on the operation unit 97, the R / W 94 reads out predetermined image data from memory 99, the image processing unit 92 performs decompression and decoding processing, and then the playback image signal is output to the display unit 93 and the playback image is displayed.

[0148] In this technology, "imaging" refers to a series of processes, some or all of them, from the photoelectric conversion process that converts the light captured by the image sensor 98 into an electrical signal, to the camera signal processing unit 91 that converts the output signal from the image sensor 98 into a digital signal, performs noise reduction, corrects image quality, and converts it into brightness and color difference signals, to the image processing unit 92 that performs compression encoding, decompression and decoding of the image signal based on a predetermined image data format and conversion of data specifications such as resolution, and finally to the R / W 94 that writes the image signal to the memory 99.

[0149] In other words, "imaging" may refer only to the photoelectric conversion process that converts the light captured by the image sensor 98 into an electrical signal, or it may refer to the process from the photoelectric conversion process that converts the light captured by the image sensor 98 into an electrical signal to the conversion of the output signal from the image sensor 98 into a digital signal by the camera signal processing unit 91, noise reduction, image quality correction, conversion to brightness and color difference signals, etc. Alternatively, "imaging" may refer to the process from the photoelectric conversion process that converts the light captured by the image sensor 98 into an electrical signal to the conversion of the output signal from the image sensor 98 into a digital signal by the camera signal processing unit 91, noise reduction, image quality correction, conversion to brightness and color difference signals, etc., to the image processing unit 92, including compression encoding / decompression decoding of the image signal based on a predetermined image data format and conversion of data specifications such as resolution. Furthermore, "imaging" may refer to processes ranging from the photoelectric conversion process that converts the light captured by the image sensor 98 into an electrical signal, to the conversion of the output signal from the image sensor 98 into a digital signal by the camera signal processing unit 91, noise reduction, image quality correction, conversion into luminance and chromatic difference signals, and the compression encoding, decompression and decoding process of the image signal based on a predetermined image data format and the conversion of data specifications such as resolution by the image processing unit 92, or it may refer to the writing process of the image signal to the memory 99 by the R / W 94.

[0150] The order of the processes described above may be changed as appropriate.

[0151] Furthermore, in this technology, the camera block 90 and the electronic equipment 100 may be configured to include only some or all of the image sensor 98, camera signal processing unit 91, image processing unit 92, and R / W 94 that perform the above processing.

[0152] Furthermore, the camera block 90 may be configured to include some of the image sensor 98, camera signal processing unit 91, image processing unit 92, and R / W 94.

[0153] <This technology> This technology can also be configured as follows:

[0154] (1) A multi-stage circuit board having a top board, a bottom board, and multiple intermediate boards is arranged inside. A first circuit pattern is formed on at least one surface in the thickness direction of the top substrate. A second circuit pattern is formed on at least one surface in the thickness direction of the bottom substrate. The intermediate substrate has multiple connecting conductors at both ends that can be connected to the first circuit pattern and the second circuit pattern via bumps, and is located between the top substrate and the bottom substrate. The multiple intermediate substrates are formed as opposing portions, with each portion positioned facing the others. The opposing portion has a joint portion provided with a plated portion and a non-joint portion not provided with the plated portion. The bottom substrate or the intermediate substrate has an injection groove formed at least on the top substrate side into which solder is injected. When the joints of adjacent intermediate substrates are facing each other, the solder injected into the injection groove flows between the joints by capillary action during heating by reflow. electronic equipment.

[0155] (2) The injection groove is formed in the bottom substrate and has a connecting portion provided with a conductive portion and a non-connecting portion not provided with the conductive portion. With the intermediate substrates positioned on both sides of the injection groove and the joints facing each other and the non-joints facing each other, the solder flows between the joints by capillary action. The electronic device described in (1) above.

[0156] (3) Multiple joints, non-joints, connectings, and non-connectings are formed, The joint portion and the non-joint portion are formed alternately. The connecting portion and the non-connecting portion are formed alternately. The electronic device described in (2) above.

[0157] (4) The volume of the non-connected portion is made larger than the volume of the connected portion. The electronic device described in either (2) or (3) above.

[0158] (5) The injection groove is formed in the bottom substrate, The entirety of the opposing portion is formed as the joint portion, The non-connecting portion is formed on the outside of the portion where the intermediate substrate is located. The electronic device described in any of (2) to (4) above.

[0159] (6) Multiple intermediate substrates are positioned spaced apart in the circumferential direction of the bottom substrate. The plurality of connecting conductors are arranged in a staggered pattern when viewed from the thickness direction. An electronic component that functions as a spacer is placed between the bottom substrate and the intermediate substrate in a non-contact manner with respect to the connecting conductor. The aforementioned electronic components are arranged at diagonal corners of the intermediate substrate, The multiple electronic components arranged sequentially in the circumferential direction of the bottom substrate are positioned alternately on the outside and inside. The electronic device described in any of (1) to (5) above.

[0160] (7) Of the multiple electronic components, the two electronic components that are spaced furthest apart are provided as positioning electronic components. The height of the positioning electronic component is made higher than the height of the other electronic components. An insertion recess is formed in the portion of the intermediate substrate where the positioning electronic component is located, into which a part of the positioning electronic component is inserted. The electronic equipment described in (6) above.

[0161] (8) Multiple intermediate substrates are positioned spaced apart in the circumferential direction of the bottom substrate. The aforementioned multiple intermediate substrates are bonded to the top substrate by side fill, which is an adhesive applied along the outer circumference of the top substrate. The top substrate is provided with a plurality of damming protrusions on its outer periphery that protrude outward and are spaced apart in the circumferential direction. Multiple intermediate substrates are joined to the top substrate with each of the gaps between them covered by the damming projections. The electronic device described in any of (1) to (7) above.

[0162] (9) The top substrate has an insulating substrate base and the first circuit pattern formed on the substrate base, The aforementioned base material is formed by cutting the portion of the original sheet that is connected via multiple joints at the intermediate part of the joints. The joint was used as the damming projection. The electronic equipment described in (8) above.

[0163] (10) In a configuration where multiple intermediate substrates are positioned spaced apart in the circumferential direction of the bottom substrate, damming walls are provided at each of the four corners to block the side fill. The electronic device described in (8) or (9) above.

[0164] (11) The intermediate substrate has an insulating base material and a conductive connecting conductor, The damming wall portion is formed from the same material as the base material. The electronic device described in (10) above.

[0165] (12) A portion of each of the multiple connecting conductors is used as a pair of first connecting lines for a differential signal circuit and a plurality of second connecting lines for a ground circuit. The pair of first connecting wires are surrounded by multiple second connecting wires. The first connection line is provided once on each of the adjacent intermediate boards, The second connection line is provided at least once on each of the adjacent intermediate substrates. The electronic device described in any of (1) to (11) above.

[0166] (13) The solder that flowed between the joints of adjacent intermediate substrates was used as the second connecting wire in a solidified state. The electronic equipment described in (12) above.

[0167] (14) It has a top substrate, a bottom substrate, and multiple intermediate substrates, A first circuit pattern is formed on at least one surface in the thickness direction of the top substrate. A second circuit pattern is formed on at least one surface in the thickness direction of the bottom substrate. The intermediate substrate has multiple connecting conductors at both ends that can be connected to the first circuit pattern and the second circuit pattern via bumps, and is located between the top substrate and the bottom substrate. The multiple intermediate substrates are formed as opposing portions, with each portion positioned facing the others. The opposing portion has a joint portion provided with a plated portion and a non-joint portion not provided with the plated portion. The bottom substrate or the intermediate substrate has an injection groove formed at least on the top substrate side into which solder is injected. When the joints of adjacent intermediate substrates are facing each other, the solder injected into the injection groove flows between the joints by capillary action during heating by reflow. Multi-stage board. [Explanation of Symbols]

[0168] 100 Electronic equipment 1 Multi-tier board 2 Top board 3 Bottom board 4. Intermediate board 5. Base material 7. Base material 9 Base material 10 Connecting conductors 11 Opposite section 11a Joint 11b Non-joint part 30 Bump 40 Bump 50 Handa 12 Injection groove 13 Connection part 14. Disconnected section 15 Conductive part 16 Plated parts 17 Space 12A injection groove 18 recesses 19 Electronic Components 19A Positioning electronic component 20 Insertion recess 300 Side Fill 400 original plates 21. Joint (damming projection) 22 Damming wall section 10X First connection line 10Y Second connection line

Claims

1. A multi-stage circuit board having a top board, a bottom board, and multiple intermediate boards is arranged inside. A first circuit pattern is formed on at least one surface in the thickness direction of the top substrate. A second circuit pattern is formed on at least one surface in the thickness direction of the bottom substrate. The intermediate substrate has multiple connecting conductors at both ends that can be connected to the first circuit pattern and the second circuit pattern via bumps, and is located between the top substrate and the bottom substrate. Each of the multiple intermediate substrates is formed as an opposing portion that is positioned opposite to another portion, The opposing portion has a joint portion provided with a plated portion and a non-joint portion not provided with the plated portion. The bottom substrate or the intermediate substrate has an injection groove formed at least on the top substrate side into which solder is injected. When the joints of adjacent intermediate substrates are facing each other and the joints are positioned continuously with the injection groove, the solder injected into the injection groove flows between the joints by capillary action when heated by reflow. electronic equipment.

2. The injection groove is formed in the bottom substrate and has a connecting portion provided with a conductive portion and a non-connecting portion not provided with the conductive portion. With the intermediate substrates positioned on both sides of the injection groove and the joints facing each other and the non-joints facing each other, the solder flows between the joints by capillary action. The electronic device according to claim 1.

3. Multiple joints, non-joints, connectings, and non-connectings are formed, The joint portion and the non-joint portion are formed alternately. The connecting portion and the non-connecting portion are formed alternately. The electronic device according to claim 2.

4. The volume of the non-connected portion is made larger than the volume of the connected portion. The electronic device according to claim 2.

5. The injection groove is formed in the bottom substrate, The entirety of the opposing portion is formed as the joint portion, The non-connecting portion is formed on the outside of the portion where the intermediate substrate is located. The electronic device according to claim 2.

6. Multiple intermediate substrates are positioned spaced apart in the circumferential direction of the bottom substrate. Multiple connecting conductors are arranged in a staggered pattern when viewed from the thickness direction. An electronic component that functions as a spacer is placed between the bottom substrate and the intermediate substrate in a non-contact manner with respect to the connecting conductor. The aforementioned electronic components are arranged at diagonal corners of the intermediate substrate, The multiple electronic components arranged sequentially in the circumferential direction of the bottom substrate are positioned alternately on the outside and inside. The electronic device according to claim 1.

7. Of the multiple electronic components, the two electronic components that are spaced furthest apart are provided as positioning electronic components. The height of the positioning electronic component is made higher than the height of the other electronic components. An insertion recess is formed in the portion of the intermediate substrate where the positioning electronic component is located, into which a part of the positioning electronic component is inserted. The electronic device according to claim 6.

8. Multiple intermediate substrates are positioned spaced apart in the circumferential direction of the bottom substrate. Multiple intermediate substrates are bonded to the top substrate by side fill, which is an adhesive applied along the outer circumference of the top substrate. The top substrate is provided with a plurality of damming protrusions on its outer periphery that protrude outward and are spaced apart in the circumferential direction. Multiple intermediate substrates are joined to the top substrate with each of the gaps between them covered by the damming projections. The electronic device according to claim 1.

9. The top substrate has an insulating substrate base and the first circuit pattern formed on the substrate base, The aforementioned base material is formed by cutting the portion of the original sheet that is connected via multiple joints at the intermediate part of the joints. The joint was used as the damming projection. The electronic device according to claim 8.

10. In a configuration where multiple intermediate substrates are positioned spaced apart in the circumferential direction of the bottom substrate, damming walls are provided at each of the four corners to block the side fill. The electronic device according to claim 8.

11. The intermediate substrate has an insulating base material and a conductive connecting conductor, The damming wall portion is formed from the same material as the base material. The electronic device according to claim 10.

12. A portion of each of the multiple connecting conductors is used as a pair of first connecting lines for the differential signal circuit and a plurality of second connecting lines for the ground circuit. The pair of first connecting wires are surrounded by multiple second connecting wires. The first connection line is provided once on each of the adjacent intermediate boards, The second connection line is provided at least once on each of the adjacent intermediate boards. The electronic device according to claim 1.

13. The solder that flowed between the joints of adjacent intermediate substrates was used as the second connecting wire in a solidified state. The electronic device according to claim 12.

14. It has a top substrate, a bottom substrate, and multiple intermediate substrates, A first circuit pattern is formed on at least one surface in the thickness direction of the top substrate. A second circuit pattern is formed on at least one surface in the thickness direction of the bottom substrate. The intermediate substrate has multiple connecting conductors at both ends that can be connected to the first circuit pattern and the second circuit pattern via bumps, and is located between the top substrate and the bottom substrate. Each of the multiple intermediate substrates is formed as an opposing portion that is positioned opposite to another portion, The opposing portion has a joint portion provided with a plated portion and a non-joint portion not provided with the plated portion. The bottom substrate or the intermediate substrate has an injection groove formed at least on the top substrate side into which solder is injected. When the joints of adjacent intermediate substrates are facing each other and the joints are positioned continuously with the injection groove, the solder injected into the injection groove flows between the joints by capillary action when heated by reflow. Multi-stage board.

Images