JP6561904B2 - Electronic component device and method of manufacturing electronic component device - Google Patents

Description

  The present invention relates to an electronic component device in which an electronic component to be surface-mounted is mounted on a circuit board, and a method for manufacturing the electronic component device.

  When a surface mount type electronic component having an electrode having a size of about 7 mm square or more on the lower surface is soldered to the circuit board, the solder that connects the circuit board and the electronic component due to the difference in thermal expansion coefficient between the circuit board and the electronic component Stress acting on the joint is generated. By repeatedly applying stress, a crack is generated in the solder joint portion, and the joint reliability between the circuit board and the electronic component is lowered. In order to improve joint reliability, several proposals have been made for providing solder joints with a thickness that can reduce the stress acting on the solder joints connecting the circuit board and electronic components to an acceptable level. Has been. Here, the joining reliability means that the joining of the electronic component and the circuit board by the solder joint portion can be maintained over a predetermined period in a predetermined use environment.

  A member is disposed on the circuit board and the electronic component in order to provide a solder joint having a thickness capable of reducing the stress acting on the solder joint connected between the circuit board and the electronic component to an acceptable level. There is a method (see Patent Document 1).

JP2001-094002

  In the method of Patent Document 1, a member for ensuring a space between the circuit board and the electronic component is used. When such a member is used, the material cost of the member and the cost in the manufacturing process increase.

  The present invention has been made to solve the above-described problems, and a solder joint portion in which an electrode on the lower surface of an electronic component is connected to a pad without using a member inserted between the circuit board and the electronic component. An object of the present invention is to obtain an electronic component device in which a solder joint portion is formed with a thickness capable of reducing the stress acting on the solder to an acceptable level, and the joint reliability is improved.

An electronic component device according to the present invention includes an electronic component having an electrode on a lower surface, a circuit board having a shape and size corresponding to the electrode of the electronic component on one surface, and the electrode A solder joint portion connected to the pad and formed to surround the hollow with a predetermined thickness , wherein the solder joint portion is a region in which no solder is placed on the pad and the electronic component; It is characterized by being formed so as to surround a hollow portion which is a space isolated from the outside sandwiched between the two .

  According to the present invention, it is possible to reduce the stress acting on the solder joint portion where the electrode on the lower surface of the electronic component is connected to the pad to an acceptable level without using a member inserted between the circuit board and the electronic component. A solder joint can be formed with a sufficient thickness, and the joint reliability can be improved.

1 is a perspective view of an electronic component device according to Embodiment 1 of the present invention. 1 is a top view of an electronic component device according to Embodiment 1. FIG. FIG. 3 is a back view of the electronic component of the electronic component device according to the first embodiment, a cross-sectional view of the electronic component device, and a top view of the circuit board. 2 is a top view and a bottom view of a circuit board included in the electronic component device according to Embodiment 1. FIG. 1 is an exploded view of an electronic component device according to Embodiment 1. FIG. 4 is a flowchart illustrating a method for manufacturing the electronic component device according to the first embodiment. In the manufacturing method of the electronic component device which concerns on Embodiment 1, it is the upper side figure of the thermal radiation pad which shows the state of the electronic component device after a solder arrangement | positioning process, and sectional drawing of an electronic component device. In the manufacturing method of the electronic component device which concerns on Embodiment 1, it is the upper side figure of the thermal radiation pad which shows the state after an electronic component mounting process, and sectional drawing of an electronic component device. In the manufacturing method of the electronic component apparatus which concerns on Embodiment 1, it is the upper side figure of the thermal radiation pad which shows the state currently heated at the soldering process, and sectional drawing of an electronic component apparatus. In the manufacturing method of the electronic component device which concerns on Embodiment 1, it is the upper side figure of the thermal radiation pad which shows the state after a soldering process, and sectional drawing of an electronic component device. FIG. 3 is a top view illustrating a state in which a crack is generated in the solder in which the lower surface electrode of the electronic component is connected to the heat dissipation pad in the electronic component device according to Embodiment 1 by virtually removing the electronic component. It is a top view of the circuit board which shows the state of the circuit board of the electronic component apparatus which concerns on Embodiment 2 of this invention, removing an electronic component virtually. FIG. 10 is a top view of a circuit board showing a state in which a crack is generated in a solder in which a lower surface electrode of an electronic component is connected to a heat dissipation pad in an electronic component device according to a second embodiment by virtually removing the electronic component. It is a top view of the circuit board which shows the state of the solder paste arrange | positioned to the thermal radiation pad of the electronic component apparatus which concerns on Embodiment 3 of this invention. It is a top view of the circuit board which shows the state of the circuit board of the electronic component device which concerns on Embodiment 3 by virtually removing an electronic component. FIG. 6 is a top view of a circuit board showing a state in which a crack is generated in a solder in which a lower surface electrode of an electronic component is connected to a heat dissipation pad in an electronic component device according to a third embodiment by virtually removing the electronic component.

Embodiment 1 FIG.
The structure of the electronic component device 20 according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of an electronic component device 20 according to the first embodiment. FIG. 2 is a top view of the electronic component device 20 shown in FIG. 3 is a back view of the electronic component 2 of the electronic component device 20 according to the first embodiment, a cross-sectional view of the electronic component device 20, and a top view of the circuit board 1. FIG. FIG. 4 is a top view and a bottom view of the electronic component device 20 according to the first embodiment. 3 is a cross-sectional view taken along the line AA of the top view of the circuit board 1 shown in the lower part of FIG.

  The electronic component device 20 includes a circuit board 1 and a surface-mount type electronic component 2 mounted on the circuit board 1. 1 to 4 show one electronic component 2 and its periphery among the electronic components 2 mounted on the electronic component device 20.

  As shown in FIG. 3, the lower surface electrode 3 is provided in the center part of the lower surface of the electronic component 2 having a substantially square shape when viewed from the upper surface. The lower surface electrode 3 is a heat radiation electrode for radiating heat generated by the operation of the electronic component 2. On one surface of the circuit board 1, a heat radiating pad 4 that is a pad having a shape and a size corresponding to the lower surface electrode 3 that is an electrode provided on the lower surface of the electronic component 2 is provided. The lower surface electrode 3 of the electronic component 2 is joined to the heat dissipating pad 4 by solder 9. The lower surface electrode 3 and the heat radiation pad 4 are thermally and electrically connected by solder 9. The heat dissipating pad 4 may be connected to a grounding portion that is maintained at the ground potential to become the ground potential. The lower electrode may not have a heat dissipation function. The circuit board may be a double-sided mounting board on which electronic components are mounted on both sides.

  A plurality of signal electrodes 5 are provided on each side of the periphery of the lower surface of the electronic component 2. The signal electrode 5 is embedded in the electronic component 2 and only the terminal portion is exposed on the lower surface and the side surface. On the surface of the circuit board 1 facing the electronic component 2, signal pads 6 are provided at positions corresponding to the respective signal electrodes 5. Each signal electrode 5 and signal pad 6 are electrically connected by solder 7.

  The heat dissipation pad 4 is provided with sixteen heat transfer through holes 12 penetrating the circuit board 1 between the heat dissipation pad 14 provided on the surface opposite to the heat dissipation pad 4 of the circuit board 1.

  As shown in FIG. 4, the heat transfer through holes 12 are evenly arranged within the range of the heat dissipation pad 4. Each of the heat transfer through holes 12 is provided with a conductor layer on the inner surface and filled with solder. A heat transfer through hole pad 13 is provided on the back surface of the circuit board 1 so as to surround the heat transfer through hole 12.

  The heat transfer through hole 12 penetrating the circuit board 1 is disposed on the back surface of the circuit board 1 through the solder filled in the heat transfer through hole 12, the inner conductive layer and the heat transfer through hole pad 13. The heat radiating part 14 is connected.

  Heat generated in the electronic component 2 is transmitted from the lower surface electrode 3 to the heat dissipation pad 4 via the solder 9. The heat transmitted to the heat dissipating pad 4 is transmitted to the heat dissipating part 14 disposed on the back surface of the circuit board 1 through the heat transfer through hole 12 filled with solder and the heat transfer through hole pad 13. According to the IPC (Institut for Interconnecting and Packaging Circuits) standard, the area of the solder 9 that is a solder joint that connects the lower surface electrode 3 to the heat radiating pad 4 as a condition for sufficiently transferring heat from the lower surface electrode 3 to the heat radiating pad 4 Is required to be 60% or more of the area of the heat dissipation pad 4. Regarding the electronic component 2, the area of the solder 9 is 60% or more of the area of the heat dissipating pad 4, so this standard is satisfied.

  When there is a gap in the connection portion between the heat radiating portion 14 and the back surface of the circuit board 1, grease is applied to close the gap to prevent a reduction in heat radiation efficiency.

  FIG. 5 is a perspective view of the electronic component device 20 from which the electronic component 2 is virtually removed. In FIG. 5, the solder 7 connecting the signal electrode 5 and the signal pad 6 is omitted. The heat dissipating pad 4 and the signal pad 6 are appropriately wired by transmission lines provided on the circuit board 1, respectively. The transmission line is not shown.

  When viewed from above, the solder 9 is formed in a shape in which four circles have the following relationship. Four circles have an overlapping portion between adjacent circles in the vertical and horizontal directions, and have an interval from a circle located obliquely. Therefore, there is a hollow portion 10 surrounded by the solder 9 and sandwiched between the heat dissipation pad 4 and the lower surface electrode 3.

  Next, the manufacturing process of the electronic component device 20 according to the first embodiment will be described with reference to FIGS.

  FIG. 6 is a flowchart for explaining a manufacturing process of the electronic component device 20 according to the first embodiment. In the ST01 solder placement step, solder paste is applied to the heat dissipating pad 4 and the signal pad 6 on the circuit board 1. In the first embodiment, a metal mask is placed on a circuit board as a method for applying the solder paste, and screen printing is used in which the solder paste placed on the circuit board is applied to a pad with a necessary shape using a squeegee. Solder may be applied using other methods.

  FIG. 7 shows a state after the solder paste is disposed on the heat dissipating pad 4 as a top view, a cross-sectional view taken along the line BB and a cross-sectional view taken along the CC line shown in the top view. The solder placement areas for placing the solder paste on the heat dissipating pads 4 are four circles centered at positions equidistant from the four corners of the heat dissipating pads. When the solder paste is crushed and widened when the electronic component 2 is placed, the spacing between the four solder placement areas is such that the solder pastes adjacent to each other on the left and right or top and bottom are joined together, and the solder pastes that are obliquely adjacent to each other Are determined so that they are not joined together. A region where the solder paste at the center of the heat dissipating pad 4 is not disposed is referred to as a solder non-arranged region. The four solder placement areas surround the solder non-placement area. In the state where the solder paste shown in FIG. 7 is arranged, the solder paste is arranged only in the solder arrangement region.

  The heat dissipating pad 4 is square. The length W of one side of the heat dissipation pad 4 is 7200 μm. Since the heat radiating pad 4 is the same size as the lower surface electrode 3, the size of the lower surface electrode 3 is also a square having a length W on one side.

  The diameter D of the solder paste arranged in a columnar shape on the heat dissipating pad 4 is about 2000 μm. The height H of the solder paste is about 150 μm. The distances X and Y between the solder pastes adjacent to each other on the left and right or top and bottom are both about 1550 μm.

  As for the position, shape, and interval at the time of placement of the solder paste, adjacent solder pastes are joined together by the pressure applied when the electronic component 2 is placed, and the heat radiation pad 4 and the lower surface electrode 3 form a hollow. It was decided to do so.

  FIG. 8 shows a state after the electronic component 2 is placed on the circuit board 1. In the electronic component placement process of ST02, the electronic component 2 is placed at a position where the lower surface electrode 3 of the electronic component 2 corresponds to the heat dissipation pad 4. At the same time, the signal electrode 5 is aligned with the position corresponding to the signal pad 6. After placing the electronic component 2 so that the position of the electrode is aligned with each pad, a pressure (2N) determined from above is applied to the electronic component 2.

  According to the experiment, when 2N pressure is applied to an electronic component placed on a solder paste arranged in a cylindrical shape with a diameter of about 2000 μm and a thickness of about 150 μm, the diameter becomes about 3600 μm, which is 1.8 times the diameter. Is obtained. Similarly, when the solder paste is applied to a cylindrical shape having a diameter of about 2000 μm and a thickness of about 130 μm, the result is that the diameter of the solder paste is 1.7 times about 3400 μm.

  The thickness of the solder paste after placing the electronic component 2 is affected by the size of the solder grains contained in the solder paste used, but it is understood that the thickness of the solder grains is arranged in one or two rows. ing.

  Since the solder paste disposed on the heat radiation pad 4 is applied in a cylindrical shape having a diameter D = about 2000 μm and a thickness H = about 150 μm, the diameter after the spread solder paste spread was obtained by experiments. The result is about 3600 μm. The distances X and Y between the solder pastes adjacent to each other on the left and right or top and bottom are both about 1550 μm. Therefore, even if the diameter of the solder paste applied in a columnar shape that is adjacent to the left or right or top or bottom or after both solder pastes are spread is smaller than about 3600 μm, it is adjacent to the left or right or top and bottom. Solder pastes to be bonded can be joined to isolate the hollow portion from the outside. In addition, as a spreading method of the spread solder paste, if the sum of the spread lengths on the adjacent side is 1550 μm or more, the solder paste adjacent to the top and bottom or the left and right is joined.

  Solder paste adjacent to the left and right or top and bottom is joined, and solder paste arranged on the diagonal line of the heat dissipating pad 4 is not joined, so that a portion where no solder is present remains in the solder non-placed area surrounded by the solder placed area. The position, interval, shape and size of the solder placement area and the solder non-placement area are determined. In addition, the solder placement region is arranged so that the solder paste spread by receiving the pressure by placing the electronic component 2 does not protrude from the range of the heat dissipation pad 4. The number of solder placement regions may be three or less or five or more. The shape of the solder placement region may not be a circle. In the case of a circle, it is easier to spread evenly, so it is easier to predict the shape after spreading by applying pressure.

  In this embodiment, the range of the solder paste that has been applied to the heat dissipation pad 4 by being pressed is within about 7150 μm square, so that it is within the range of the lower electrode pad 4.

  In FIG. 8, the figure which shows the shape of the solder paste on the thermal radiation pad 4, and sectional drawing of the electronic component apparatus 20 in an EE cut surface are shown. The thickness F of the solder paste after applying the pressure of 2N which is a pressure determined by placing the electronic component 2 is about 45 μm. A hollow portion 10 is formed by the solder paste, the heat radiating pad 4 and the lower surface electrode 3 in the central portion of the heat radiating pad 4. The thickness of the solder paste at the portion sandwiched between the electronic component 2 and the signal pad 6 is also F. The thickness F of the solder paste will be discussed later.

  In FIG. 9, the state at the time of the reflow heating of the electronic component apparatus 20 is shown. In the soldering process of ST03, the electronic component 2 is connected to the circuit board 1 by heating to melt the solder paste and solidifying the melted solder. A reflow furnace is used for heating. When the heating is stopped after the electronic component device 20 is heated to melt the solder paste and the temperature is lowered, the molten solder is solidified, and the electronic component 2 is joined to the circuit board 1 by the solder 9 and the solder 7.

  FIG. 9 shows a state in which the entire electronic component device 20 is heated at a peak temperature of about 245 ° C. in a reflow furnace. During reflow heating, the solder paste melts. The void 8 generated inside the molten solder moves to the boundary surface with the air around the molten solder or the boundary surface with the hollow portion 10. The void 8 that has moved to the outside of the molten solder goes out into the atmosphere. The void 8 that has moved to the boundary surface with the hollow portion 10 is surrounded by the lower surface electrode 3, the heat radiation pad 4, and the molten solder, and therefore cannot move from the hollow portion 10 and remains in the hollow portion 10.

  The pressure of the gas existing in the hollow portion 10 is higher than the atmospheric pressure around the electronic component device 20. The pressure of the gas confined in the hollow portion 10 supports the electronic component 2.

FIG. 10 shows a state after the reflow heating is finished and the melted solder is solidified.
When the reflow heating is finished and the ambient temperature is lowered, the molten solder is solidified. The solidified solder is the solder 9. The temperature at which the molten solder solidifies is about 220 ° C. to 183 ° C. At this temperature, since the gas confined in the hollow part 10 maintains a pressure higher than the external pressure, the mounted electronic component 2 is supported by the pressure of the gas confined in the hollow part 10.

  When the ambient temperature decreases to room temperature and the pressure of the gas confined in the hollow portion 10 decreases, the solidified solder 9 exists. The electronic component 2 is supported by the solder 9. The thickness of the solder 9 is kept substantially the same as the thickness F after being spread.

  When the electronic component 2 is extended at a high temperature during operation, and when the temperature at the subsequent stop is reduced and contracted, there is a difference in the thermal expansion coefficient between the electronic component 2 and the circuit board 1. Stress is applied to the solder 9 connecting 3 to the heat radiation pad 4. When this stress repeatedly acts on the solder 9, cracks may occur in the solder 9.

  In order to suppress the occurrence of cracks in the solder 9 in which the lower surface electrode 3 is connected to the heat dissipation pad 4, it is necessary to reduce the stress acting on the solder 9 to an allowable level. In order to reduce the stress acting on the solder 9 to an acceptable level, the solder 9 needs to be thickened to some extent.

  According to the experiment, when the heat radiation pad 4 is a 7 mm square, if the thickness of the solder 9 is about 10 μm or more, the stress acting on the solder 9 can be reduced to an acceptable level. .

  In this embodiment, the thickness F of the solder 9 is about 45 μm. The thickness of the solder 9 formed in this embodiment can be reduced to such an extent that the stress acting on the solder 9 can be allowed. When the area of the heat dissipating pad 4 is increased, the thickness necessary for reducing the stress acting on the solder 9 to an acceptable level is increased, but the thickness is determined by an experiment or the like.

  As described above, the thickness is such that the stress acting on the solder 9 connecting the lower surface electrode 3 to the heat radiating pad 4 can be reduced to an acceptable level without using a spacer or the like used in the prior art. Solder 9 can be formed.

  By forming the solder 9 having a sufficient thickness, the stress acting on the solder 9 connecting the electronic component and the circuit board can be reduced to an acceptable level, and the solder 9 connecting the electronic component and the circuit board can be reduced. It is possible to suppress the occurrence of cracks. Even when a crack occurs, it is possible to prevent the crack from spreading over the entire solder 9.

  FIG. 11 shows an example in which a crack 11 occurs in the solder 9 of the electronic component device 20 according to the first embodiment. FIG. 11 is a view showing a part of the circuit board 1 centering on the heat radiation pad 4. FIG. 11 is a view in which the electronic component 2 is virtually removed so that the solder 9 can be seen.

  In the first embodiment, since there is a hollow portion 10 where no solder is present in the central portion of the heat dissipation pad 4, even if a crack generated in a part of the solder 9 extends, the crack extends by reaching the hollow portion 10. Stops. That is, the hollow portion 10 does not spread cracks throughout the solder 9. Since cracks do not spread over the entire solder 9, problems such as peeling of electronic components are less likely to occur, and joint reliability can be improved.

Embodiment 2. FIG.
In Embodiment 1, the solder 9 which connected the lower surface electrode 3 of the electronic component to the heat radiating pad 4 has one hollow part. The electronic component device 20 according to the second embodiment is a case where the hollow portion is divided into a plurality of parts.

  FIG. 12 is a top view of the circuit board 1 and a bottom view of the electronic component 2 of the electronic component device 20 according to the second embodiment. FIG. 12 is a diagram in which the electronic component 2 is virtually removed so that the solder 9b can be seen. In this embodiment, four solders 9b each surrounding the hollow portion 10b are formed. The formed four solders 9b are evenly arranged on the heat dissipation pad 4.

  In this embodiment, four solder non-arrangement regions are determined at approximately the center of each range obtained by dividing the entire heat radiation pad 4 into four equal squares. Solder paste is respectively disposed in a plurality of solder placement areas provided so that each of the four solder non-placement areas is surrounded by the plurality of solder placement areas. By placing the electronic component 2 and applying pressure, the solder paste spreads. The spread solder paste is adjacent to the top and bottom or left and right, and four donut-shaped solder pastes are formed. When the doughnut-shaped solder paste is melted and solidified, the solder 9b surrounds the hollow portion 10b. Four solders are formed. A space surrounded by the lower surface electrode 3 of the electronic component 2 (not shown), the solder 9b, and the heat dissipation pad 4 is a hollow portion 10b.

  In this embodiment, the electronic component 2 can be supported by a plurality of solders 9b having a hollow portion 10b. In the case of the first embodiment, one hollow portion 10 is provided in the central portion of the heat dissipation pad 4. Since there is one hollow portion, the electronic component 2 may be inclined with respect to the circuit board 1 depending on the state of placement of the electronic component 2 when the solder paste is melted.

  In this embodiment, since the plurality of solders 9b having the hollow portions 10b are provided, the probability that the electronic component 2 is tilted can be reduced, and even if it is tilted, the tilt can be kept small.

  The total area of the four solders 9 b is 60% or more of the area of the heat dissipation pad 4. Since the solder is disposed in 60% or more of the area of the heat dissipation pad 4, the heat generated in the electronic component can be efficiently transmitted to the heat dissipation pad 4 and the heat dissipation portion 14.

  FIG. 13 shows an example where cracks 11b are generated in the solder 9b in the second embodiment. FIG. 13 shows the second embodiment in which the electronic component 2 is virtually removed so that the solder 9b can be seen. Since the hollow portion 10b is formed by the heat radiation pad 4, the solder 9b, and the lower surface electrode 3 of the electronic component 2 (not shown) at a plurality of locations, even when the crack 9b occurs in the solder 9b, a plurality of hollow portions are formed. The distance to reach any one of 10b is shortened. Since the distance until the crack 11b reaches the hollow portion 10b is shortened, the crack is difficult to spread over the entire solder 9b. Since cracks are difficult to spread over the entire solder 9b, the bonding reliability between the circuit board 1b and the electronic component 2b is increased.

  Compared with the case where the hollow portion 10 is provided only at one central portion of the heat dissipation pad 4, the extension of cracks is easily suppressed, and the bonding reliability between the circuit board 1 and the electronic component 2 can be improved. .

Embodiment 3 FIG.
The third embodiment is a case where a solder dispenser is used when a solder paste is disposed on the heat radiation pad 4. FIG. 14 is a diagram showing a state of solder paste disposed on the heat dissipating pad 4 of the electronic component device 20 according to the third embodiment.

  FIG. 14 is a view in which a solder paste is arranged in an annular shape on the heat radiation pad 4 with a solder dispenser without any breaks. The solder placement area where the solder paste is placed is provided so as to surround the solder non-placement area without a break. The closed line that becomes the boundary between the solder placement area and the solder non-placement area is referred to as a first closed line. The closed line that forms the outer periphery of the solder placement region is referred to as a second closed line. A region sandwiched between the first closed line and the second closed line is a solder placement region.

  When the solder paste is disposed, the solder paste is disposed so as to be about 33% or more of the area of the heat radiation pad 4 when the thickness of the solder paste is about 150 μm. By arranging in this way, the area expanded by the pressure applied after the solder paste is placed on the electronic component 2 becomes 60% or more with respect to the area of the heat radiation pad 4c. An appropriate distance is provided between the solder placement region and the outer periphery of the heat dissipating pad 4 so that the solder does not come out of the heat dissipating pad 4 even if the solder spreads.

  In this embodiment, by using a solder dispenser, the solder paste can be arranged in an annular shape so as to surround a certain region without a break. By using the solder dispenser, the degree of freedom of arrangement of the solder paste is increased. It is also possible to provide a plurality of solder non-arrangement areas where no solder paste is arranged, and to arrange the solder paste in a well-balanced manner on the entire heat dissipating pad 4 so as to surround each solder non-arrangement area seamlessly. When a plurality of solder non-arrangement areas are provided on the heat dissipating pad 4, the solder arrangement areas surrounding each solder non-arrangement area may be provided so as to be separated from each other. One solder placement region may be provided so as to have a plurality of solder non-placement regions inside. In that case, the 2nd closed line used as the perimeter of a solder arrangement field will surround a plurality of 1st closed lines. A second closed line may be provided around all the first closed lines to determine the solder placement area. The first closed line and the second closed line are such that all non-solder placement areas are surrounded by the solder placement area, ie, all first closed lines are surrounded by the second closed line. You just have to decide the line.

  The solder paste is spread by applying a predetermined pressure (2N) after placing the electronic component 2 on the solder paste shown in FIG. In this state, the electronic component device 20 is reflow-heated to melt the solder paste, and the solder 9c is solidified when the temperature is lowered thereafter. FIG. 15 shows a state in which the solder 9c is formed by solidifying after the solder paste is melted. FIG. 15 is a diagram showing the electronic component 2 virtually removed. As shown in FIG. 15, a hollow portion 10 c is formed on the heat dissipation pad 4 by the solder 9 c, the heat dissipation pad 4, and the lower surface electrode 3 of the electronic component 2 (not shown). The solder 9c spreads in a range that fits inside the heat dissipation pad 4, and joins the lower surface electrode 3 and the heat dissipation pad 4.

  FIG. 16 is a diagram illustrating a state in which the solder 9c is cracked by virtually removing the electronic component 2. Even in this case, the extension of the crack 11c is prevented by the solder non-arrangement region provided in the central portion. Since the extension of the crack is suppressed before the crack 11c spreads over the entire solder 9c, the bonding reliability between the circuit board 1 and the electronic component 2 can be increased. The solder paste may be arranged in a plurality of rings.

  The present invention can be freely combined with each other, or can be modified or omitted within the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 Circuit board 2 Electronic component 3, 3b, 3c Lower surface electrode 4, 4b, 4c Heat radiation pad 5, 5b, 5c Signal electrode 6 Signal pad 7 Solder 8 Void 9, 9b, 9c Solder (solder joint part)
10, 10b, 10c Hollow part (hollow)
11, 11b, 11c Crack 12 Heat transfer through hole 13 Heat transfer through hole pad 14 Heat radiation part 20 Electronic component device

Claims (11)

An electronic component having an electrode on the lower surface;
A circuit board provided on one surface with a pad having a shape and size corresponding to the electrode of the electronic component;
Said electrode comprising a said I was connected to the pad junction,
The solder joint portion is an electronic component device formed so as to surround a hollow portion which is a space separated from the outside sandwiched between a solder non-arrangement region which is a region where solder is not disposed on the pad and the electronic component. . The solder joint, the electronic component device according to claim 1, characterized in that it is formed so as to surround a plurality of the hollow portion. With a heat dissipation part,
The electronic component device according to claim 1, wherein the pad is connected to the heat dissipation unit. With a grounding section,
The electronic component device according to claim 1, wherein the pad is connected to the ground portion.   5. The electronic component device according to claim 1, wherein the solder joint portion is provided in 60% or more of the area of the pad. 6. Solder is placed at a determined thickness in a plurality of solder placement areas that have a predetermined spacing surrounding a solder non-placement area, which is an area where solder is not placed on a pad provided on one side of a circuit board. Solder placement process,
An electronic component mounting step of placing an electronic component having an electrode on the lower surface on the circuit board so that the electrode is positioned at a position corresponding to the pad, and applying a predetermined pressure;
Heating with the electronic component mounted on the circuit board to melt the solder, and the soldering step of connecting the electrode to the pad by solidifying the molten solder,
The spacing is determined such that when the solder to which the pressure is applied spreads, the adjacent spread solder joins to each other, and a portion where no solder exists in the solder non-arrangement region remains .
The electronic component placing step forms a hollow portion that is surrounded by the solder to which the pressure is applied, the electronic component, and the solder non-arrangement region, and is a space isolated from the outside. A method for manufacturing a component device.   7. The solder placement step, wherein the solder is placed in a plurality of solder placement areas provided so that each of the plurality of solder non-placement areas is surrounded by the plurality of solder placement areas. The manufacturing method of the electronic component apparatus as described in 1 ..   8. The method of manufacturing an electronic component device according to claim 6, wherein in the solder placement step, the solder is placed by screen printing. A first closed line surrounding a solder non-arrangement region that is a region where solder is not disposed on a pad provided on one surface of the circuit board; and a second closed line surrounding the first closed line; A solder placement step of placing solder at a predetermined thickness in a solder placement region that is sandwiched between
An electronic component mounting step of placing an electronic component having an electrode on the lower surface on the circuit board so that the electrode is positioned at a position corresponding to the pad, and applying a predetermined pressure;
Heating with the electronic component mounted on the circuit board to melt the solder, and the soldering step of connecting the electrode to the pad by solidifying the molten solder ,
In the electronic component mounting step, a hollow part that is a space surrounded by the solder, the electronic component, and the solder non-arrangement region and isolated from the outside is formed .   In the solder placement step, a plurality of the first closed lines, and the second closed lines determined so that all the first closed lines are surrounded by the second closed lines; The method of manufacturing an electronic component device according to claim 9, wherein the solder is arranged in the solder arrangement region sandwiched between two.   11. The method of manufacturing an electronic component device according to claim 6, wherein the solder is placed by a dispenser in the solder placement step. 11.

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