JP2005005629A - Electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve heat-radiating characteristics of an electronic device, especially to improve heat-radiating characteristics of an electronic device using an interposer substrate. <P>SOLUTION: The electronic device has an electronic substrate having a first circuit substrate whereon an electronic component is mounted and a second circuit substrate electrically connected to the first circuit substrate and fixed to a housing, and the housing whereto the electronic substrate is fixed. A structure wherein the first circuit substrate is fixed to the housing in a space wherein it is not superposed with the second circuit substrate is employed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic device that requires a high heat dissipation structure represented by an engine control unit.
[0002]
[Prior art]
Usually, electronic devices are subjected to a thermal cycle test before shipping. In particular, in an in-vehicle electronic control device such as an ECU, the temperature in the vehicle body changes greatly due to the on / off of the engine or a change in environmental temperature, and a thermal cycle in a wide temperature range (usually −40 degrees to 120 degrees: automotive electronics Specifications that can withstand the general environmental test rules for equipment (JASOD001) are required. Nowadays, since the ECU tends to be arranged closer to the engine, the upper limit specification of this temperature range tends to be higher. Therefore, the in-vehicle electronic device is required to have higher heat dissipation than a general electronic device.
[0003]
In recent years, an electronic device such as a semiconductor device is mounted on an interposer board (intermediate circuit board), and a structure in which the interposer board is mounted on a mother board (circuit board) by solder bumps has been increasingly used. .
[0004]
Since it has a structure in which two boards, a motherboard and an interposer board, are sandwiched between an electronic component that is a heat source and a housing that is a heat dissipation destination, heat dissipation is low compared to a structure in which electronic components are directly mounted on a conventional motherboard. Become.
[0005]
As a technique for improving heat dissipation, a metal core substrate in which a wiring layer and an insulating layer are formed on both surfaces of a metal plate, which is a core material, is used as an interposer substrate, and a resin layer and a part of the wiring layer on both surfaces of the interposer substrate are used. There is a structure in which a semiconductor device which is an electronic component is directly mounted on the upper surface side of the core material by a face-up method, and the lower surface side of the core material and the upper surface side of the motherboard are connected by solder and plating. (Patent Document 1, FIG. 34).
[0006]
[Patent Document 1] Japanese Patent Laid-Open No. 2003-46022
[0007]
[Problems to be solved by the invention]
However, in the above conventional technology, attention has been paid to heat radiation between the interposer board and the motherboard mounted in the housing, but it is fully studied to improve the heat radiation performance of the entire electronic device including the housing. Was not.
[0008]
That is, an object of the present invention is to improve heat dissipation of an electronic device.
[0009]
[Means for Solving the Problems]
The present application includes a plurality of inventions that can solve the above-described problems, and typical ones are described below.
[0010]
A housing, and an electronic board bonded to the housing, the electronic board being electrically connected to the first circuit board (interposer board) on which electronic components are mounted and the first circuit board In an electronic device that is connected and has a second circuit board (motherboard) fixed to the casing, the interposer board is fixed to the casing in a space that does not overlap with the motherboard. Therefore, the area that can be used for fixing can be increased, and the following effects are obtained.
[0011]
(1) Since the adhesion area is increased, disconnection between the interposer substrate and the motherboard can be suppressed even when a strong impact such as dropping is applied.
[0012]
(2) By using such a space as a heat dissipation path, a large heat dissipation path that directly leads to the housing can be formed.
[0013]
Moreover, it is preferable to fix the 1st circuit board of the said aspect to this housing | casing through the member shape | molded separately from the 2nd circuit board.
[0014]
There is a limit to the shape (area and thickness) that can be formed by plating, etc. However, if it is molded in advance as a separate part, there is no need to worry about the limit of area or thickness, and fixing a large area at low cost become able to. In addition, a heat dissipation path having a large cross-sectional area can be secured by using a member having a large thermal conductivity coefficient.
[0015]
Further, in the above aspect, the second circuit board includes a through hole, and the second circuit board is located in a space between the first circuit board and the housing and overlapping the through hole. It is preferable to provide a separately molded member.
[0016]
Thus, by providing the through hole in the second substrate, the non-overlapping space between the first circuit board and the second circuit board can be arranged in the center of the second circuit board. That is, since the heat radiating member can be arranged directly under the electronic component which is a heat radiating source, the heat dissipation is improved.
[0017]
Of course, from the viewpoint of heat dissipation, it is preferable to use a member having a higher thermal conductivity than the second circuit board.
[0018]
When high reliability is required, such as for automotive applications, it is preferable to fill a space where the first substrate and the second substrate overlap with a gel-like insulator.
[0019]
Moreover, it is preferable that at least one of the bonding surfaces of the member and the first circuit board, or / and at least one of the bonding surfaces of the member and the housing have irregularities.
[0020]
In addition, when the member is a projection of the casing formed by part of the casing, it is possible to prevent a decrease in thermal conductivity due to the adhesive layer used for connection, which contributes to an improvement in heat dissipation.
Also, when using a metal core substrate as the first circuit board, the heat dissipation can be further improved by exposing the metal plate at a part of the back surface and bonding the part and the housing. it can.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 shows a perspective view of an engine control unit (ECU) module, which is an example of an electronic device, with a lid removed.
[0022]
The ECU module is mounted on the aluminum casing 27 and is electrically connected to the aluminum casing 27 (with a lid not shown) in which a connector for inputting / outputting signals from / to the outside is formed. A mother board (circuit board) 15, a semiconductor package 41 mounted on the mother board 15, and a silicone gel filling the inside of the housing 27 are provided.
[0023]
Silicone gel may be omitted, but in this example, it is filled from the viewpoint of improving reliability.
[0024]
FIG. 1 is a cross-sectional view of FIG.
[0025]
The semiconductor package 41 is a circuit board (interposer board) 11 having a resin layer and a circuit layer 13, and is die-bonded to the interposer board 11 with an adhesive 5, and is electrically connected to the circuit layer 13 by a bonding wire 3. A semiconductor device 1 that is a power supply IC, and a resin 7 that molds the interposer substrate 11 so as to seal the semiconductor device 1, the bonding wire 3, and the circuit layer are provided. The adhesive 5 used for die bonding is a silver paste containing silver as a filler in a resin.
[0026]
The mother board 15 is a circuit board including a resin layer and a circuit layer 13, and an electronic component 21 is mounted with solder 23 and a semiconductor package 41 is mounted with BGA (ball grid array) solder 19.
[0027]
The mother board 15 includes a through hole in a region overlapping with a region where the semiconductor device 1 is mounted on the interposer substrate.
[0028]
The casing 27 includes a protrusion 29, and this protrusion is fitted into the through hole of the mother board 15, and the protrusion 29 and the interposer substrate 11 are fixed with an adhesive 31. Further, locations other than the protrusions 29 are bonded to the mother board 15 with an adhesive 25. For the adhesive 31, a resin adhesive 31 in which a silver filler is contained in silicone is used, and for the adhesive 25, a silver paste is used.
[0029]
In this way, by connecting the protrusions 29 of the housing 27 to the interposer substrate 11 using the through holes of the mother board 15, the heat accumulated in the interposer substrate 11 due to the heat generated by the semiconductor device 1 is highly thermally conductive. Since it can escape to a high housing | casing with the short heat dissipation path | route formed with the material, the heat dissipation of an electronic device can be improved.
[0030]
The resin adhesive 31 is used for a resin paste containing a filler having a higher thermal conductivity than a resin such as a metal other than silver or a metal inorganic compound such as alumina, or a solder having a higher thermal conductivity than the resin layer of the circuit board. It can also be changed.
[0031]
In addition, the resin of the resin adhesive 31 can be made of a material other than silicone as long as the adhesiveness can be ensured. In this example, the BGA solder connection caused by the difference in thermal expansion coefficient between the interposer substrate and the mother board is used. In order to suppress thermal fatigue failure of the part, destruction of the silver paste itself, and interface peeling, a silicone resin paste having a Young's modulus smaller than that of the solder material used for the BGA solder connection part is used. The same effect can be obtained with grease and sheet in addition to the silicone resin.
[0032]
Next, a manufacturing process of the ECU module of FIG. 1 will be described.
[0033]
FIG. 3 is a diagram showing a manufacturing process of the ECU module of FIG.
[0034]
First, the manufacturing process of the semiconductor package 41 will be described (FIG. 3A).
[0035]
A 5 mm square semiconductor device 1 is placed face up on the surface of the interposer substrate 11 and die-bonded with solder or silver paste 5. After die bonding, the terminal of the semiconductor device and the pad of the interposer substrate are electrically connected by the bonding wire 3. Next, the electronic component 9 is mounted. This connection method is appropriately selected according to the type of electronic component. Next, in order to improve handleability and reliability, it molds with resin 7. Next, a solder BGA connection pad is formed on the back surface of the package substrate. This pad was formed by nickel plating and further gold plating with a diameter of 0.6 mm and a pitch of 1.27 mm. Further, this pad was formed on the back surface of the position where the semiconductor device 1 was formed, in a region excluding a region slightly larger than the size of the semiconductor device 1. At the same time as forming the pad, a metal layer of about 5 mm square is formed in the removed area. A Sn3Ag0.5Cu solder ball 19 having a diameter of 0.76 mm was mounted on the BGA connection pad and reflowed to form a solder bump. The aluminum casing 27 was formed by machining a projection 29 having a 5 mm square and a height of 2.0 mm by milling.
[0036]
Next, a manufacturing process of the mother board 15 will be described.
[0037]
A resin substrate (printed substrate, thickness: 1.5 mm) is prepared, and a through hole 43 is formed on the substrate by router processing at a desired position (FIG. 3B).
[0038]
Next, joining of the mother board 15 and the semiconductor package 41 will be described.
[0039]
The semiconductor package 41 and the electronic component 21 are aligned and mounted at a predetermined position on the mother board 15, and the solder is melted at 240 ° C. for about 5 minutes and reflow-connected (FIG. 3C). The size of the through hole was 7 mm square. Since the aluminum protrusion 29 is arranged in the through hole 41 of the motherboard, by making the opening portion larger than the size of the aluminum protruding portion, the condition of the alignment accuracy with respect to the housing of the substrate is eased. This is effective as a space for storing a surplus of the adhesive 31 that bonds the package and the aluminum protrusion.
[0040]
Next, a process for bonding a mother board on which an interposer substrate is mounted to an aluminum casing will be described.
[0041]
A silicone paste 25 is applied to a substrate mounting portion of an aluminum housing with a protrusion, and the protrusion has a silver paste 31 containing, as a main component, silicone having a high thermal conductivity and a low Young's modulus, and containing a silver filler. Is applied (FIG. 3D). A mother board (state (C)) having a through-hole on which components are mounted is mounted on an aluminum casing and cured at 150 ° C. for 1 hour. From the hole of the motherboard, the protruding portion 29 formed in the previous aluminum casing protrudes from the substrate surface by about 0.5 mm. Since the solder ball height for electrically connecting the package and the substrate is about 0.4 mm, the substrate thickness is 1.6 mm, and the silicone adhesive thickness is about 0.1 mm, the total is about 2.1 mm. The thickness of the silver paste 31 may be about 0.1 mm.
[0042]
It can be said that the structure of the above aspect has the following characteristics.
[0043]
First, a housing and an electronic substrate bonded to the housing are provided. The electronic substrate is electrically connected to the interposer substrate on which the electronic component is mounted, the interposer substrate substrate, and the electronic substrate. In the electronic apparatus having the first motherboard on the motherboard fixed to the casing, the interposer substrate is fixed to the casing in a space that does not overlap with the motherboard.
[0044]
Such a structure is not affected by the difference in thermal expansion coefficient between the interposer substrate and the mother board, so that stronger fixation can be obtained. By not interposing the motherboard, there are no restrictions on the fixing method and the bonding area can be increased. Therefore, even if a strong impact such as dropping is applied due to the increase in the adhesion area, there is an effect that the disconnection between the interposer substrate and the mother board can be suppressed. Moreover, since heat can be radiated without interposing a mother board, a large heat radiating path leading directly to the housing can be formed.
[0045]
The interposer substrate is preferably fixed to the housing via a member formed separately from the mother board.
[0046]
Conventionally, there is a limit to the shape (area and thickness) that can be formed by plating, etc. However, if it is molded in advance as a separate part, the area and thickness limits do not have to be considered much, and the large area is low cost. It can be fixed. Further, by using a member having a large thermal conductivity coefficient as such a member, a heat radiation path having a large cross-sectional area can be secured.
[0047]
Further, it is preferable that the motherboard has a through hole, and a member formed separately from the motherboard is provided in a space between the interposer substrate and the housing and overlapping the through hole.
[0048]
Thus, by providing the through hole in the mother board, the non-overlapping space between the interposer board and the mother board can be arranged at the center of the mother board. That is, since the heat radiating member can be disposed immediately below the electronic component that is the heat radiating source, the cross-sectional area of the path to the housing can be increased, and the heat dissipation is improved.
[0049]
Of course, from the viewpoint of heat dissipation, it is preferable to use a member having a higher thermal conductivity than the resin layer of the mother board as the above-described member.
[0050]
In a vehicle-mounted electronic device, the above structure is particularly effective because a space in which the interposer substrate and the motherboard overlap is filled with a gel-like insulator.
[0051]
Further, since the member is a projection of the casing in which a part of the casing is molded, a decrease in thermal conductivity due to the adhesive layer used for connection can be prevented, which contributes to an improvement in heat dissipation.
[0052]
Next, another structure different from FIG. 1 will be described.
[0053]
FIG. 4 is a cross-sectional view of the joule that is different from the ECU shown in FIG.
[0054]
The aluminum casing 27 is almost flat on the inner surface side as before. A separately formed aluminum metal block 33 is produced, and this is bonded to the aluminum casing 27 using a silicone adhesive 35 containing a metal filler.
[0055]
According to this embodiment, not only can the fixing strength be improved and the heat dissipation can be improved, but also the restriction on the alignment accuracy of the substrate with respect to the housing can be relaxed. The adhesive 31 is preferably a resin paste containing a powder of silver, other metal having a high thermal conductivity, or a metal inorganic compound such as alumina, or a solder having a higher thermal conductivity in terms of heat dissipation characteristics.
[0056]
In addition, by using a silicone-based resin paste, grease, or sheet with a low Young's modulus as the adhesive, thermal fatigue damage to the BGA solder joint can be mitigated, and damage to the silver paste itself and interface peeling can be mitigated. This is desirable for connection reliability.
[0057]
FIG. 5 is different from the embodiment shown in FIG. 1 in the following points. The substrate constituting the package is a metal core substrate 37, a part of the insulating resin on the front and back surfaces of the metal core substrate is removed, and the chip 1 with high heat generation is bonded to the exposed portion of the core metal with the silver paste 5 by face-up, so as to be electrically connected. Are connected to bonding pads on the package substrate by wire bonding 3. When other components are mounted on the package substrate as necessary and the resin mold 7 is used, the handleability can be improved. The aluminum casing protrusion 33 is bonded to the exposed portion of the core metal on the back surface of the package with a silicone-based silver paste 31. According to this embodiment, since the high heat generating chip and the aluminum housing having a large heat capacity can be connected without the insulating resin layer of the circuit board having a low thermal conductivity, the heat dissipation can be extremely enhanced. Moreover, it is also possible to maintain the insulation between the core metal and the aluminum casing by using either or both of the adhesive portions 31 and 35 as an adhesive containing a non-conductive filler or an adhesive without a filler.
[0058]
FIG. 6 is different from the above-described embodiment in that the connection between the core metal 39 and the aluminum protruding portion 33 is performed by the solder ball 45. The manufacturing process can be simplified by making the heat dissipation part a solder ball connection. Although the total connection area contributing to heat dissipation is reduced, the thermal conductivity of the solder itself is about 10 times larger than that of the silver paste. If the entire silver paste connection portion in the above-described embodiment is connected by solder instead of the solder ball, the heat dissipation is further improved.
[0059]
A manufacturing process for realizing the embodiment shown in FIG. 6 is briefly shown in FIG. 7 and described below.
[0060]
First, a manufacturing method of the package part is shown (upper part of FIG. 7C). A metal core substrate 37 is used as the package substrate. The metal core substrate is manufactured by a known method. However, it is necessary to remove the insulating resin portion, which is performed by carbonic acid laser processing. After the desmear treatment, a high heat generation electronic component 1 of about 5 mm square is die-bonded to the surface of the core metal 39 with solder or silver paste 5 face up. Electrical connection is made by wire bonding 3. Furthermore, in order to improve handling property and reliability, it molds with resin 7. A solder BGA connection pad is formed on the back surface of the package substrate. This pad has, for example, a diameter of 0.6 mm and a pitch of 1.27 mm, and is subjected to nickel plating and further gold plating. This BGA pad is not formed on the entire back surface of the substrate, leaving a part of a 5 mm square area for heat dissipation. The above process is also effective for the embodiment shown in FIG. Insulating resin removing portions (bottle portions) having a diameter of 0.6 mm and a pitch of 1.27 mm are formed in this heat radiation region. This counterbore part is formed by the same method as the chip mounting part, that is, by laser processing. If the counterbore diameter is approximately the same size as other BGA pads, the supplied solder ball size can be made the same, thereby facilitating process management. Moreover, heat dissipation can be improved by decreasing the pitch of the spot facing portion to increase the number or increasing the area of the spot facing portion. The Sn3Ag0.5Cu solder balls 19 and 45 having a diameter of 0.76 mm are mounted on the BGA connection pad and the heat-dissipating counterbore, respectively, and reflowed to form solder.
[0061]
A projection 33 having a 5 mm square and a height of 1.7 mm is formed at a desired position on the ECU aluminum casing. This protrusion is formed by the method as in the previous embodiment. A metallization for solder connection, that is, nickel having a thickness of 5 microns, or gold plating having a thickness of 0.5 microns is formed on the protrusion so as to match the solder pattern for heat dissipation on the back surface of the package. This metallization may be anything as long as it reacts with solder, and the formation method may be anything such as sputtering.
[0062]
The substrate is a resin substrate (printed substrate, thickness: 1.5 mm) by a known technique, and holes are formed in this substrate by router processing at a desired position. The hole size is 6 mm square. By making it larger than the size of the aluminum protruding portion, it is possible to relax restrictions on the alignment accuracy of the substrate with respect to the housing.
[0063]
In this embodiment, a silicone adhesive is applied to the substrate mounting portion of the aluminum housing with the protrusions, and the substrate with the holes is mounted and cured at 150 ° C. for 1 hour. From the hole of the substrate, the protruding portion formed in the previous aluminum casing protrudes about 0.2 mm from the surface of the substrate.
[0064]
The previous package and other electronic components are aligned and mounted at predetermined positions on the substrate, the solder is melted at 240 ° C. for about 5 minutes, and all the solder connection portions are simultaneously reflow-connected.
[0065]
The metal protrusions and substrate openings for heat dissipation are the same size as the mounted chip in the above embodiment, but heat dissipation can be further improved if they are larger than the chip size. Further, if the metal protrusion and the substrate opening are smaller than the chip size, the wiring area of the substrate increases, and the substrate size can be reduced. In addition, the horizontal cross-sectional shape of the heat dissipating part does not necessarily need to be square or rectangular, and if the shape is round or rounded, the surface tension plays an important role in alignment. It is possible to improve reliability by avoiding stress concentration.
[0066]
FIG. 8 shows the structure of another electronic device.
[0067]
A difference from the electronic device of FIG. 1 is that a minute groove or protrusion 100 is provided on the uppermost surface of the protrusion 29.
[0068]
In the structure of FIG. 1, the adhesive 31 composed of a resin adhesive or solder is interposed between the protrusion 29 and the interposer substrate 11, so that a minute interval is generated on the connection surface, but a minute protrusion is provided. Accordingly, by pressing the protrusions against the interposer substrate while securing the adhesive force with the grooves, these intervals can be reduced, so that the heat dissipation can be improved.
[0069]
FIG. 9 shows the structure of another electronic device.
[0070]
A difference from the electronic device of FIG. 4 is that minute grooves or protrusions 101 and 102 are provided on the upper and lower surfaces of the metal block 33.
[0071]
In the structure of FIG. 4, the adhesive 31 composed of a resin adhesive or solder is interposed between the metal block 33 and the mother board 15 and between the metal block 33 and the interposer substrate 11, so that a minute interval is formed. It occurs on the connecting surface. However, by providing minute protrusions on the upper and lower surfaces of the metal block 33, the distance between the protrusions can be reduced by pressing the protrusions against the interposer substrate while securing the adhesive force with the grooves, thereby improving heat dissipation. be able to.
[0072]
The uneven metal block formed by the protrusions and grooves has the same effect when applied to the metal blocks shown in FIGS. However, it is preferable that the upper surface of the metal block having the structure of FIG.
[0073]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the heat dissipation of an electronic device can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an electronic device.
FIG. 2 is a perspective view of an ECU module.
FIG. 3 is a cross-sectional view showing a manufacturing process of the structure of FIG. 1;
FIG. 4 is a cross-sectional view of an electronic device.
FIG. 5 is a cross-sectional view of an electronic device.
FIG. 6 is a cross-sectional view of an electronic device.
FIG. 7 is a diagram showing a manufacturing process;
FIG. 8 is a cross-sectional view of an electronic device.
FIG. 9 is a cross-sectional view of an electronic device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Semiconductor device, 3 ... Bonding wire, 5 ... Resin adhesive, 7 ... Mold resin, 9 ... Electronic component, 11 ... Interposer substrate, 13 ... Circuit layer, 15 ... Motherboard, 17 ... Circuit layer, 19 ... Solder bump, DESCRIPTION OF SYMBOLS 21 ... Electronic component, 23 ... Solder, 25 ... Resin adhesive, 27 ... Aluminum housing | casing, 29 ... Protrusion, 31 ... Resin adhesive, 33 ... Metal block, 35 ... Resin adhesive, 37 ... Metal core board | substrate, 39 ... Core metal (Inner layer metal plate), 41 ... semiconductor package, 43 ... through hole, 45 ... solder ball for heat dissipation

Claims (18)

A housing and an electronic substrate bonded to the housing;
The electronic substrate is
A first circuit board on which electronic components are mounted;
In an electronic device having a second circuit board that is electrically connected to the first circuit board and fixed to the housing,
The electronic device, wherein the first circuit board is fixed to the housing in a space that does not overlap with the second circuit board. In claim 1,
The electronic device, wherein the first circuit board is fixed to the housing via a member formed separately from the second circuit board. In claim 1 or 2,
The second circuit board has a through hole;
An electronic device comprising: a member formed separately from the second circuit board in a space between the first circuit board and the housing and overlapping the through hole. In any one of Claim 1 to 3,
The electronic device is characterized in that the member has a thermal conductivity larger than that of the second circuit board. In any one of Claim 1-4,
An electronic device, wherein a space in which the first substrate and the second substrate overlap is filled with a gel-like insulator. In any of claims 2 to 5,
A structure in which the member and the housing are bonded to a solder or resin by a resin adhesive containing a filler having a higher thermal conductivity than the resin;
A structure in which the member and the first circuit board are bonded to a solder or resin by a resin adhesive containing a filler having a higher thermal conductivity than the resin;
Alternatively, an electronic device having a structure including both of them. In any of claims 2 to 6,
An electronic device, wherein at least one of an adhesion surface of the member and the first circuit board, or at least one of an adhesion surface of the member and the housing is uneven. In any of claims 2 to 5,
The electronic device according to claim 1, wherein the member is a projection of a casing in which a part of the casing is molded. In claim 8,
The electronic device is characterized in that the member and the first circuit board are bonded to each other with an adhesive containing solder having a higher thermal conductivity than that of resin. In claim 8 or 9,
An electronic device, wherein at least one of the bonding surface of the member and the first circuit board has irregularities. In claim 2,
The first circuit board is a metal core board in which a resin layer and a circuit layer are formed on both surfaces of a metal plate,
The metal plate is exposed at a part of the back surface,
The exposed portion and the housing are connected via the member. In claim 11,
The electronic device according to claim 1, wherein the metal plate has irregularities on a connection surface with the member. In claim 3,
An electronic device characterized in that there is a gap between the member and the side wall of the through hole. In claim 2,
More than the Young's modulus of the solder used to connect the circuit on the front surface of the second circuit board and the circuit on the back surface of the first circuit board, between the member and the first circuit board, or the member An electronic device having a smaller Young's modulus of an adhesive or solder used for bonding to the first circuit board. In claim 11,
The first circuit board has a region where the metal plate is exposed on the surface thereof,
An electronic device, wherein the semiconductor device is die-bonded on a metal plate in the region, and a first circuit board circuit layer and a terminal of the semiconductor device are bonded by wire bonding. In claim 2,
An electronic apparatus, wherein the member and the first circuit board are fixed with an adhesive containing silicone filler. In claim 2,
An electronic apparatus, wherein the second circuit board and the first circuit board are connected by lead-free solder containing Sn and Ag. A housing and an electronic substrate bonded to the housing;
The electronic substrate is
A first circuit board on which electronic components are mounted;
In an electronic device having a second circuit board that is electrically connected to the first circuit board and fixed to the housing,
An electronic device, wherein the first circuit board is fixed to a housing without passing through a second circuit board.

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