JP5213663B2 - Electronic device mounting structure - Google Patents

Description

  The present invention relates to a mounting structure for an electronic device in which an electronic component is housed in a recessed portion of an electronic component housing package having a recess on an upper surface of an insulating base and a wiring conductor formed from the recess to one side surface. In particular, the present invention relates to a mounting structure in which one side surface of an insulating substrate is mounted to face an external electric circuit board.

  Conventionally, MEMS (Micro Electro Mechanical Systems), semiconductor integrated circuit elements such as IC and LSI, LDs (semiconductor lasers), LEDs, which have mechanisms as sensor elements such as acceleration sensors and gyro sensors Electronic component storage packages that store optical semiconductor elements such as (light emitting diodes), PDs (photodiodes), line sensors, and image sensors, vibrators such as ceramic piezoelectric elements, crystal resonators, and other various electronic components Generally, it is made of a ceramic such as an aluminum oxide sintered body, and has a rectangular parallelepiped insulating base having a recess for accommodating electronic components on the upper surface, and a wiring conductor formed from the inside of the recess to the lower surface of the insulating base. Structure.

  Then, the electronic parts are accommodated in the recesses of the insulating base, and the electrodes for signal, grounding, power supply, etc. of the electronic parts are connected to the corresponding wiring conductors via solder or bonding wires, and the mounting part is covered with the lid. The electronic device is completed by sealing. In order to increase the reliability of the sealing, there is a case where a metal frame is joined to the upper surface of the insulating base so as to surround the recess, and the lid is joined to the metal frame by a welding method such as seam welding. is there.

In such an electronic device, the lower surface of the insulating base faces the external electric circuit board, and the portion of the wiring conductor formed on the lower surface of the insulating base is soldered to the corresponding terminal of the external electric circuit board. It is bonded and mounted via a bonding material.
Japanese Patent Laid-Open No. 3-62559 JP 2006-66721 A

  In recent years, in order to keep the occupied area of an external electric circuit board of an electronic device small, a wiring conductor is formed from the mounting portion of the insulating base to one side surface, and the wiring conductor formed on the one side surface is connected to the external electric circuit board. The mounting structure of an electronic device that is connected to the device has been used. The mounting structure of the electronic device in this case is so-called side mounting in which the insulating substrate is mounted in the vertical direction so that the side surface of the insulating substrate faces the external electric circuit board.

  However, in the case of such side mounting, it is necessary to form a wiring conductor on the side surface narrower than the lower surface of the insulating base and to connect this wiring conductor to the external electric circuit board. It is difficult to secure a sufficient connection area for. Therefore, there is a problem that it is difficult to increase the mounting reliability of the electronic device with respect to the external electric circuit board. In particular, with the recent miniaturization of electronic devices, the area of the side surface of the insulating base has become even narrower, so the solution of such problems has become more important.

  An object of the present invention is to provide an electronic device in which an electronic component is housed in a concave portion on the upper surface of an insulating base and a wiring conductor is formed from the concave portion of the insulating base to one side surface. An object of the present invention is to provide a mounting structure capable of increasing the bonding strength when mounted.

  In the mounting structure of the electronic device according to the present invention, a wiring conductor is formed from the inner side to the one side surface of the concave portion on a rectangular parallelepiped insulating base having a concave portion for accommodating electronic components on the upper surface, and the concave portion is surrounded on the upper surface. An electronic component storage package formed by bonding a metal frame, an electronic component housed in the recess and electrically connected to the wiring conductor, and bonded to the metal frame to seal the recess. The wiring conductor formed on one side surface of the insulating substrate, wherein the electronic device is mounted with an electronic device including a stopped lid so that the one side surface faces the external electric circuit board. Is connected to the external electric circuit board, and the outer surface of the metal frame is bonded to face the external electric circuit board.

Further, the mounting structure of the electronic device of the present invention having the above structure, in that the lid is made of a metallic material, is joined to the external electric circuit board via the junction member to the metal frame and together It is a feature.

  In the electronic device mounting structure of the present invention, in the above configuration, the side surface of the metal frame is bonded to a ground terminal provided on the external electric circuit board via a conductive bonding material. It is a feature.

  According to the electronic device mounting structure of the present invention, the wiring conductor provided on the one side surface of the insulating base body is connected to the external electric circuit board, and the outer side surface of the metal frame is connected to the external electric circuit. Since it is bonded facing the board, in addition to the connection between the wiring conductor and the external electric circuit board, the bonding of the electronic device to the external electric circuit board is effectively performed by bonding the metal frame and the external electric circuit board. Can be reinforced. For this reason, for example, even if the connection area between the wiring conductor and the external electric circuit board is reduced in accordance with the miniaturization of the electronic apparatus, the electronic apparatus can be firmly bonded to the external electric circuit board. Therefore, in the mounting structure in which one side surface of the insulating base is mounted facing the external electric circuit board, it is possible to provide a mounting structure capable of increasing the bonding strength of the electronic device.

  According to the electronic device mounting structure of the present invention, in the above configuration, when the lid is made of a metal material and joined to the external electric circuit board through the joining material together with the metal frame, the metal frame In addition to the bonding of the body and the external electric circuit board, the bonding of the electronic device to the external electric circuit board can be more effectively reinforced by the bonding of the lid and the external electric circuit board. Therefore, it is possible to provide a more reliable electronic device mounting structure.

  According to the electronic device mounting structure of the present invention, in the above configuration, when the side surface of the metal frame is bonded to the ground terminal provided on the external electric circuit board via the conductive bonding material. Can use the metal frame and the lid as a conductor for supplying a ground potential. These metal frames and lids can ensure a sufficiently large area as compared with the case where, for example, a grounding wiring conductor is formed on an insulating base. Therefore, a mounting structure in which the ground potential in the electronic device is more stable can be obtained.

  The electronic device mounting structure of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a sectional view showing an example of an embodiment of a mounting structure for an electronic device according to the present invention. In FIG. 1, 1 is an insulating substrate, 2 is a wiring conductor, 3 is a metal frame, 4 is an electronic component, and 5 is a lid. A wiring conductor 2 is formed on an insulating substrate 1 having a concave portion 1a on the upper surface, and a metal frame 3 is joined to surround the concave portion 1a to constitute an electronic component storage package (no symbol). In addition, the electronic component 4 is accommodated in the recess 1 a of the electronic component storage package, and the lid 5 is joined to the metal frame 3 to constitute the electronic device 9. The electronic device 9 is mounted on the external electric circuit board 7 and one side surface of the insulating base 1 is mounted facing the external electric circuit board 7.

  The insulating substrate 1 is made of an electrically insulating material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a silicon nitride sintered body, a silicon carbide sintered body, or a glass ceramic sintered body. Become. If the insulating substrate 1 is made of, for example, an aluminum oxide sintered body, an appropriate organic binder and solvent are added to and mixed with ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, etc. None, using a doctor blade method to form a sheet, to obtain a plurality of ceramic green sheets. After that, the ceramic green sheets are cut and punched into a suitable shape, and a plurality of these are obtained. Finally, the ceramic green sheet laminate is laminated and fired at a temperature of about 1600 ° C. in a reducing atmosphere.

  In addition, by laminating a frame-shaped ceramic green sheet produced by punching the central portion over a plurality of layers following the uppermost layer or the uppermost layer at the time of this lamination, the central portion of the upper surface is laminated. The insulating substrate 1 having the recess 1a can be produced.

  The insulating substrate 1 functions as a substrate for hermetically sealing the electronic component 4. The electronic component 4 includes a MEMS (Micro Electro Mechanical Systems: so-called micromachine) element, a semiconductor integrated circuit element such as an IC or LSI, an LD (semiconductor laser) having a mechanism as a sensor element such as an acceleration sensor or a gyro sensor. ), LED (light emitting diode), PD (photodiode), CCD, line sensor, image semiconductor and other optical semiconductor elements, piezoelectric vibrators, crystal vibrators, and other various functional elements and passive elements. .

  The insulating base 1 has a shape suitable for housing the electronic component 4 in the recess 1a. For example, the insulating substrate 1 is a plan view suitable for housing the rectangular electronic component 4 such as a MEMS element or a piezoelectric vibrator. It is formed in a rectangular shape. Specifically, when the electronic component 4 is a MEMS element, the insulating base 1 has a long side length of about 10 mm, a short side length of about 8 mm, and a thickness of about 3 mm. . Also, in the case of accommodating an electronic component 4 such as a vibrator, one having a side length of about 1.5 to 3 mm and a thickness of about 0.5 to 0.75 mm is often used. Yes. The insulating base 1 may be one in which corners are chamfered in an arc shape to prevent breakage of the corners.

  A wiring conductor 2 is formed from the inside of the recess 1a of the insulating base 1 to one side surface. The wiring conductor 2 is a conductive path for electrically connecting the electronic component 4 accommodated in the recess 1 a to the external electric circuit board 7.

  The electrode of the electronic component 4 is electrically connected to the part formed inside the recessed part 1a among the wiring conductors 2 via the bonding wire (no code | symbol). A portion of the wiring conductor 2 formed on one side surface of the insulating base 1 is connected to a terminal (not shown) of the external electric circuit board 7 by a conductive connecting material 6 such as solder. The electrodes of the electronic component 4 are electrically connected to the external electric circuit board 7 through the wiring conductor 2.

  The wiring conductor 2 is made of a metal material such as tungsten, molybdenum, manganese, copper, silver, palladium, or gold. For example, if the wiring conductor 2 is made of tungsten, a metal paste prepared by kneading tungsten powder with an organic solvent and a resin binder is printed on a ceramic green sheet to be the insulating substrate 1 by a method such as screen printing. In addition, it can be formed by co-firing with the insulating substrate 1 (laminated body of ceramic green sheets).

  Further, the insulating base 1 has a frame-shaped metal layer (no reference) formed on the upper surface so as to surround the recess 1a. This metal layer is a base metal layer for joining the metal frame 3 made of a metal material such as an iron-nickel-cobalt alloy. The metal frame 3 is joined to the metal layer by a brazing material (not shown) such as silver brazing.

  The frame-shaped metal layer can be formed of the same metal material as that of the wiring conductor 2. If the frame-like metal layer is made of, for example, tungsten, the metal paste similar to that for forming the wiring conductor 2 is the portion surrounding the concave portion 1a of the ceramic green sheet serving as the insulating base 1, that is, the uppermost layer. It can be formed by printing and applying a frame-like pattern on the upper surface of the frame-shaped ceramic green sheet by screen printing and co-firing with the insulating substrate 1 (laminated body of ceramic green sheets).

  The metal frame 3 is for joining the lid 5 that seals the recess 1a. That is, the lid 5 made of a metal material such as iron-nickel alloy or iron-nickel-cobalt alloy is joined to the upper surface of the metal frame 3 by a joining means such as resistance welding, electron beam welding, brazing, or the like. Is closed with a lid 5, and an electronic component 4 is hermetically sealed inside a container including the insulating base 1, the metal frame 3, and the lid 5.

  If the metal frame 3 is made of, for example, an iron-nickel-cobalt alloy, the plate material of the iron-nickel-cobalt alloy is subjected to processing such as appropriate rolling, punching, or etching to form a predetermined frame. Manufactured by molding.

  The shape of the metal frame 3 is, for example, a square frame shape with a rectangular inner periphery. As a result, the electronic component 4 that is generally in the shape of a rectangular parallelepiped, such as a semiconductor integrated circuit element or a piezoelectric vibrator, can be efficiently surrounded without taking a useless space. The metal frame 3 may be configured such that each corner is chamfered in an arc shape to prevent chipping or the like from occurring at the corner.

  For joining the metal frame 3 to the frame-shaped metal layer, a brazing material such as silver brazing (so-called preform) is interposed between the metal layer and the lower surface of the metal frame 3, and the brazing material is heated and melted. And then joining.

  And the electronic component 4 is accommodated in the recessed part 1a of the insulation base | substrate 1, the electrode is electrically connected to the wiring conductor 2, and the cover body 5 on the upper surface of the metal frame 3 is a joining means (welding, brazing etc.) mentioned above. ) To form an electronic device 9 in which the electronic component 4 is hermetically sealed in the electronic component storage package. When the lid 5 is joined to the metal frame 3 by such joining means, one made of a metal material such as iron-nickel-cobalt alloy or iron-nickel alloy is used.

  The electronic device 9 is mounted by so-called side surface mounting in which one side surface of the insulating base 1 is mounted facing the external electric circuit board 7. In this mounting structure, the wiring conductor 2 formed on one side surface of the insulating base 1 is made of solder or the like on an external electric circuit board (for example, an electric circuit board constituting an electronic device such as a computer or a communication device such as a motherboard). It is connected via a conductive connecting material 6.

  In such side mounting, the wiring conductor 2 formed on one side surface of the insulating base 1 functions as a pad for connecting the electronic device 9 to the external electric circuit board 7. In accordance with the function as the pad, a portion of the wiring conductor 2 formed on one side surface of the insulating base 1 is formed in a pattern such as a square shape or an oval shape.

  The electronic device 9 is mounted on the side surface by reducing the occupied area when the electronic device 9 is viewed in plan with respect to the external electric circuit board 7 as much as possible, or by disposing the electronic component 4 sealed in the electronic device 9. The purpose is to connect to the external electric circuit board 7 in this direction so as to function effectively. For example, when the electronic component 4 is an acceleration sensor element and it is desired to detect acceleration in a direction perpendicular to the main surface of the external electric circuit board 7, the acceleration sensor element (electronic component 4) in which the detection unit is formed. Such a side surface mounting is performed because it is necessary to dispose the main surface) so as to be perpendicular to the main surface of the external electric circuit board 7.

  In the mounting structure of the electronic device 9, the outer surface of the metal frame 3 is bonded to face the external electric circuit board 7. Thus, in addition to the connection between the wiring conductor 2 and the external electric circuit board 7, the outer surface of the metal frame 3 is joined to face the external electric circuit board 7. 7 can be effectively reinforced. Therefore, for example, even when the connection area between the wiring conductor 2 and the external electric circuit board 7 is reduced in accordance with downsizing of the electronic device 9 or the like, the electronic device 9 is firmly bonded to the external electric circuit board 7. Can do. Therefore, in the mounting structure in which one side surface of the insulating substrate 1 is mounted facing the external electric circuit board 7, it is possible to provide a mounting structure that can increase the bonding strength of the electronic device 9.

  The side surface of the metal frame 3 and the external electric circuit board 7 are bonded using, for example, a bonding material 8 such as solder, resin adhesive (insulating material), or conductive adhesive. If the metal frame 3 is to be joined to the external electric circuit board 7 with solder, a metal layer (not shown) is previously applied to the portion of the external electric circuit board 7 that faces the outer surface of the metal frame 3. The metal frame 3 and the external electric circuit 7 can be joined by providing and soldering a solder paste between the metal layer and the metal frame 3. As the solder, tin-lead solder (eutectic solder), tin-silver solder, tin-silver-bismuth solder, tin-silver-copper solder, or the like can be used. Note that the solder that is the bonding material 8 may be spread and bonded from the outer surface of the metal frame 3 to the exposed surface of the frame-shaped metal layer.

  In this case, the solder which is the conductive connecting material 6 used when connecting the wiring conductor 2 to the external electric circuit board 7 and the solder which is the above-mentioned bonding material 8 are set as the same solder, and the wiring conductor 2 Can be connected to the external electric circuit board 7 and the metal frame 3 and the external electric circuit board 7 (dummy metal layer or the like) at the same time (for example, in the same reflow furnace). A mounting structure that can easily improve the workability of mounting on the external electric circuit board 7 may be adopted.

  In such a mounting structure of the electronic device 9, when a conductive material such as solder is used as the bonding material 8, the bonding material 8 spreads from the frame-shaped metal layer onto one side surface of the insulating base 1, and the metal It is necessary to pay attention to a problem that the frame 3 and the wiring conductor 2 are electrically short-circuited through the bonding material 8. For example, as shown in FIG. 2, for example, a frame-shaped metal layer for joining the metal frame 3 is separated from the outer edge of the upper surface of the insulating base 1, and the metal layer and the metal frame 3 What is necessary is just to ensure a fixed distance between the upper end (left end in FIG. 2) of one side surface of the insulating base 1. In this way, by suppressing the frame-shaped metal layer on which the bonding material 8 may spread from one side surface of the insulating base 1, it is possible to suppress the bonding material 8 from spreading on one side surface of the insulating base 1. it can. FIG. 2 is an enlarged cross-sectional view of a main part showing another example of the embodiment of the mounting structure of the electronic device 9 of the present invention. In FIG. 2, the same parts as those in FIG.

  If a resin adhesive such as a resin adhesive or a conductive adhesive is used as the bonding material 8, for example, a glass-epoxy resin substrate (so-called FR-4 or the like) is used as an insulating substrate (no symbol). The metal frame 3 can also be bonded directly to the used external electric circuit board 7 by the bonding material 8.

  Here, the specific example which measured the joining strength of the electronic device 9 and the external electric circuit board | substrate 7 in the mounting structure of the electronic device 9 of this invention is given.

  In this example, the insulating substrate 1 is made of an aluminum oxide sintered body, is a square flat plate having a side dimension of about 3 mm, and a thickness of about 0.75 mm. Silicon oxide and magnesium oxide are applied to the aluminum oxide powder. Five layers of ceramic green sheets prepared by adding the raw material powder prepared by adding the organic powder and the binder into a sheet shape by a doctor blade method were laminated and fired at 1600 ° C. On the upper surface of the insulating substrate 1, a concave portion 1 a was formed by punching the upper three ceramic green sheets into a frame shape.

  A wiring conductor 2 made of a tungsten metallization layer is formed from the inside of the recess 1 a to one side surface of the insulating substrate 1, and a portion of the wiring conductor 2 formed on one side surface of the insulating substrate 1 is connected to the external electric circuit board 7. The pad was formed in a square shape having a side dimension of about 0.15 mm, and 10 wiring conductors 2 having this shape and dimension were arranged on one side surface of the insulating base 1 with an adjacent interval of about 0.12 mm.

  The upper surface of the insulating substrate 1 has a frame shape with a width of 0.25 mm surrounding the recess 1a. A frame-like metal layer is formed on the upper surface with a width of about 0.2 mm, and the metal layer is silver- A metal frame 3 (thickness: about 0.2 mm) made of an iron-nickel-cobalt alloy is joined using a copper eutectic brazing material, and a silicon (Si) plate is accommodated as a dummy electronic component in the recess 1a. After bonding to the bottom surface of 1a with an adhesive, a lid 5 made of iron-nickel-cobalt alloy was joined on the metal frame 3 by a seam welding method to produce an electronic device 9 for testing.

  In this electronic device 9, the wiring conductor 2 formed on the outer surface of the metal frame 3 and one side surface of the insulating base 1 is joined (connected) to the external electric circuit board 7 with tin-silver (Sn-3.5 Ag) solder. The mounting structure of the electronic device 9 of the present invention was formed. In this mounting structure, the electronic device 9 was pulled in the opposite direction to the external electric circuit board 7, and the force when the electronic apparatus 9 was peeled off from the external electric circuit board 7 was measured to measure the bonding strength of the electronic device 9. Further, as a comparative example, the bonding strength was measured in the same manner for a conventional mounting structure in which only the wiring conductor 2 formed on one side surface of the insulating base 1 was connected to the external electric circuit board 7. The mounting structure of the comparative example was the same as the mounting structure of the present invention except that the outer surface of the metal frame 3 was not joined to the external electric circuit board 7.

  As a result, the bonding strength of the electronic device 9 was about 20 N in the mounting structure of the present invention, whereas it was 6 N in the comparative example, and the bonding strength of the electronic device 9 can be increased in the mounting structure of the present invention. Was confirmed.

  Further, in such a mounting structure of the electronic device 9, for example, as shown in FIG. 3, the lid 5 is made of a metal material, and is joined to the external electric circuit board 7 through the joining material 8 together with the metal frame 3. In this case, in addition to the joining of the metal frame 3 and the external electric circuit board 7, the joining of the electronic device 9 to the external electric circuit board 7 is more effective by the joining of the lid 5 and the external electric circuit board 7. Can be reinforced. Therefore, a mounting structure in which the bonding strength of the electronic device 9 to the external electric circuit board 7 is higher can be obtained. FIG. 3 is an enlarged cross-sectional view of the main part showing another example of the embodiment of the mounting structure of the electronic device 9 of the present invention. In FIG. 3, the same parts as those in FIG.

  As a metal material used for producing the lid 5, an alloy material such as copper or aluminum can be used in addition to the iron-nickel-cobalt alloy and the iron-nickel alloy described above. However, since the metal frame 3 and the lid 5 are joined by the same joining material 8, the metal frame 3 and the lid 5 are the same metal material in consideration of workability at the time of joining, securing of joining strength, and the like. It is preferable to make it consist of.

  The lid 5 and the external electric circuit board 7 are joined, for example, in order to join the lid 5 and the external electric circuit board 7 in addition to joining the outer surface of the metal frame 3 and the external electric circuit board 7. A necessary amount of solder paste can be interposed between the outer surface of the metal frame 3 and the side surface of the lid 5 and the external electric circuit board 7 and heat-bonded.

  In this case, if the bonding material 8 such as solder spreads on the upper surface of the lid 5, the amount of the bonding material 8 for bonding the lid 5 or the metal frame 3 and the external electric circuit board 7 is reduced. In addition, the bonding strength between the metal frame 3 and the lid 5 and the external electric circuit board 7 may be reduced, and the effect of reinforcing the bonding of the electronic device 9 may be reduced. Therefore, it is preferable that the lid 5 is configured to prevent the bonding material 8 from flowing unnecessarily on the upper surface thereof.

  For example, if the bonding material 8 is solder, the flow of the bonding material 8 to the upper surface of the lid 5 is suppressed only on the side surface of the lid 5 (or the outer edge of the upper surface in contact with the side surface and the side surface). For example, by depositing a plating layer (not shown) such as a gold plating layer having good solder wettability on the portion only). Such partial plating layer deposition may be performed by, for example, covering the portion of the lid 5 where the plating layer is not deposited with an insulating material such as a resin material and subjecting the lid 5 to electrolytic plating. This can be done by any method.

  Further, in the mounting structure of the electronic device 9 of the present invention, for example, as shown in FIG. 4, the side surface of the metal frame 3 is interposed via the ground terminal G provided on the external electric circuit board 7 and the conductive bonding material 8. Can be used as conductors for supplying a ground potential. FIG. 4 is an enlarged cross-sectional view of the main part showing another example of the embodiment of the mounting structure of the electronic device 9 of the present invention. 4, parts similar to those in FIG. 1 are denoted by the same reference numerals.

  These metal frame body 3 and lid body 5 can ensure a wider area than when the grounding wiring conductor 2 is formed on the insulating base 1, for example. Therefore, a mounting structure in which the ground potential in the electronic device 9 is more stable can be obtained. For example, when the electronic component 4 is a semiconductor integrated circuit element, the ground potential is used for switching during operation such as computation. The ground terminal G provided on the external electric circuit board 7 is, for example, an electric circuit (not shown) for electrically connecting the ground terminal G and a terminal connected to the wiring conductor 2 to the external electric circuit board 7. Can be electrically connected to the electronic component 4 through the electric circuit and the wiring conductor 2.

It is sectional drawing which shows an example of embodiment of the mounting structure of the electronic device of this invention. It is a principal part expanded sectional view which shows the other example of embodiment of the mounting structure of the electronic device of this invention. It is a principal part expanded sectional view which shows the other example of embodiment of the mounting structure of the electronic device of this invention. It is a principal part expanded sectional view which shows the other example of embodiment of the mounting structure of the electronic device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Insulating base | substrate 1a ... Recessed part 2 ... Wiring conductor 3 ... Metal frame 4 ... Electronic component 5 ... Lid 6 ... Connection material 7 ... External electric circuit board 8 ... Joint 9 ... Electronic device G ... Ground terminal

Claims (3)

An electronic device in which a wiring conductor is formed from the inside of the recess to one side surface on a rectangular insulating base having a recess for accommodating electronic components on the upper surface, and a metal frame is joined to the upper surface so as to surround the recess. An electronic device comprising: a component storage package; an electronic component that is housed in the recess and electrically connected to the wiring conductor; and a lid that is bonded to the metal frame and seals the recess. The mounting structure of the electronic device is mounted so that the one side surface faces the external electric circuit board, and the wiring conductor formed on one side surface of the insulating base is connected to the external electric circuit board. And a mounting structure for an electronic device, wherein an outer surface of the metal frame is bonded to face the external electric circuit board. Mounting structure of the lid is made of a metal material, an electronic device according to claim 1, characterized in that it is joined to the external electric circuit board via the junction member to the metal frame and together. 2. The electronic device mounting structure according to claim 1, wherein a side surface of the metal frame is bonded to a ground terminal provided on the external electric circuit board via a conductive bonding material.

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