JP5572007B2 - Electronic device and manufacturing method thereof - Google Patents

Description

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

  Conventionally, in order to improve the integration density of electronic components, an electronic device in which connection terminals of electronic components are surface-mounted on lands of a wiring board has been used.

  There are various types of electronic components used in this type of electronic device, such as sizes and shapes, and the shapes of connection terminals are also different. In some cases, electronic components are desired to be more compact, and it is difficult to accurately form connection terminals of electronic components, and the heights of the plurality of connection terminals differ from the mounting surface of the electronic components on the wiring board. There is a case. Moreover, even if the height of the connection terminal of the electronic component is formed with high accuracy, the connection terminal may be deformed by an external force or the like in a subsequent transport process or the like. The connection terminal of the electronic component in which the connection terminal is deformed has different flatness of the connection terminal. In an electronic device in which electronic components having different flatnesses of connection terminals are surface-mounted on a wiring board, the connection terminals of the electronic components are lifted from the lands of the wiring board. Electronic components with different flatness of connection terminals may not be able to join the connection terminals and lands by soldering even if they are surface-mounted on the wiring board, which may cause poor bonding between the electronic parts and the wiring board. .

As to suppress joining defects, as shown in FIG. 7 (c), a plurality of connection terminals 2d, the tip of 2e the height difference h ₀ different electronic component dimensions (see Figure 7 (b)) Each of the connection terminals 2d and 2e includes a wiring board 3 having a plurality of lands 4f that are joined by joints 5 made of solder (see white arrows in FIG. 7A). There is known an electronic device including a wide portion 41 for increasing the height of the molten solder 24 to be joined to the connection terminals 2d and 2e (for example, see Patent Document 1).

In the electronic device shown in FIG. 7C, the wide portion 41 is provided in each land 4f, so that the solder height of the wide portion 41 is partially increased by the surface tension of the molten solder 24 (FIG. 7 ( see c)). The electronic device shown in FIG. 7C is melted even if there is a dimensional difference h ₀ between the height of the connection terminal 2e from the wiring board 3 side and the height of the connection terminal 2d from the wiring board 3 side. The solder 24 can suppress the occurrence of bonding failure between the connection terminal 2e and the land 4f due to the floating of the connection terminal 2e.

JP 2001-230521 A

  However, in the electronic device, the amount of solder of the joint portion 5 made of solder for joining the connection terminals 2e and 2d and the land 4f is different (see FIG. 7C), so that each connection terminal of the electronic component The bonding strength between 2e and 2d and the land 4f is different. For this reason, in an electronic device used for a particularly stressed application, there is a fear that the bonding strength between the electronic component and the wiring board 3 may not be sufficient, and further improvement in the bonding strength is required.

  Further, the electronic device uses an electronic component in which the shape of each of the connection terminals 2d and 2e is corrected so that the flatness of each of the connection terminals 2d and 2e of the electronic component matches. Alternatively, in the electronic device, after the connection terminals 2d and 2e of the electronic component are soldered onto the lands 4f of the wiring board 3, manual operation or human operation is performed so as to fill a gap between the connection terminals 2e and the lands 4f. The additional solder to replenish the solder is performed by equipment work instead of the above. In the electronic device, the connection failure is improved by correcting the shape of the connection terminals 2d and 2e and performing additional soldering.

  However, correction of the shape of the connection terminal 2e in the electronic component and additional soldering in the gap between the connection terminal 2e and the land 4f lead to an increase in the manufacturing cost of the electronic device. In addition, it is difficult to manufacture an electronic device by accurately controlling the amount of additional solder, and there is a possibility that a bonding failure due to excessive or insufficient solder may not be improved.

  The present invention has been made in view of the above reasons, and its purpose is to provide an electronic device with higher bonding reliability of a bonding portion made of solder without correcting the shape of the connection terminal in the electronic component and its It is to provide a manufacturing method.

An electronic device according to the present invention includes an electronic component having a surface-mount package and a wiring having a plurality of lands on a surface to which a plurality of connection terminals of the electronic component are joined by joints made of solder. An electronic device comprising a substrate, wherein the plurality of connection terminals are used as a reference for a height position from the one surface of the wiring board, and the first connection terminals are: Second connection terminals having different height positions from the one surface, wherein the plurality of lands are a first land to which the first connection terminals are joined, and the second connection terminals are The first land, which is joined, has a second land having a different height from the one surface , and a first distance that is a distance between the first connection terminal and the first land; The difference between the second distance, which is the distance between the second connection terminal and the second land, Height of the second lands so as to be smaller than the flatness of the serial plurality of connection terminals, characterized by comprising a set.

  In this electronic device, the electronic component includes an LED chip housed in the surface mount package, and the first connection terminal is connected to the LED chip protruding from the surface mount package on the side surface side. In addition to being an electrode terminal for power supply, the second connection terminal is a heat radiating terminal that protrudes from the outer bottom surface side of the surface mount package and radiates the heat of the LED chip to the outside.

  In this electronic device, the electronic component includes an LED chip housed in the surface mount package, and the first connection terminal protrudes from the outer bottom surface side of the surface mount package and heats the LED chip. And the second connection terminal is an electrode terminal for supplying power to the LED chip protruding from the surface-mount package to the side surface side.

The method for manufacturing an electronic device according to the present invention is a method for manufacturing the electronic device, wherein the first land and the height of the second land are formed on one side by half-etching at the time of forming the joint. A metal mask formed with recesses having different depths according to the difference is disposed on the wiring board with the one surface side of the metal mask facing the one surface side of the wiring board, and the metal mask Providing the solder on each of the first land and the second land from through holes provided in the plurality of recesses of the metal mask by solder printing using
A step of joining the first connection terminal and the second connection terminal of the electronic component to the first land and the second land, respectively, by a joint made of the solder by a reflow soldering method. It is characterized by.

  The electronic device of the present invention has a remarkable effect that it is possible to provide an electronic device with higher bonding reliability of a bonding portion made of solder without correcting the shape of the connection terminal in the electronic component.

  The method for manufacturing an electronic device according to the present invention makes it possible to manufacture an electronic device having a higher bonding reliability of a bonding portion made of solder with high productivity without correcting the shape of the connection terminal in the electronic component. There is a great effect.

The electronic device of Embodiment 1 is shown, (a) is a schematic sectional view, (b) is a side view of an essential part, and (c) is a sectional view of another essential part. The electronic component used for an electronic device same as the above is shown, (a) is a top view, (b) is a front view, (c) is a bottom view. FIG. 6 is a schematic explanatory diagram illustrating a main part of an electronic device according to a second embodiment. The electronic device of Embodiment 3 is shown, (a) is a schematic sectional drawing, (b) is a side view of the principal part, (c) is sectional drawing of another principal part. The electronic component used for an electronic device same as the above is shown, (a) is a top view, (b) is a front view, (c) is a side view. It is a schematic sectional drawing which shows the manufacturing process of an electronic device same as the above. It is principal part explanatory drawing which shows the conventional electronic device.

(Embodiment 1)
Hereinafter, the electronic device of this embodiment will be described with reference to FIGS. 1 and 2. In addition, the same number is attached | subjected about the same member.

  An electronic device 10 shown in FIG. 1 of the present embodiment includes an electronic component 1 that functions as a light-emitting diode 1A having a surface-mount package 11, and a plurality of (here, three) connection terminals 2a of the light-emitting diodes 1A. , 2b, 2c are provided with a wiring substrate 3 having a plurality of (here, three) lands 4a, 4b, 4c on one surface 3a, which are joined by joints 5 made of solder.

  In addition, the light emitting diode 1A used in the electronic device 10 includes a plurality of connection terminals 2a, 2b, and 2c that are connected to the first connection terminals 2a and 2b that serve as a reference for the height position from the one surface 3a of the wiring board 3. The first connection terminals 2a and 2b include a second connection terminal 2c having a height different from the one surface 3a (see FIG. 1B).

In particular, in the electronic device 10 of the present embodiment, the plurality of lands 4a, 4b, and 4c are connected to the land 4b that is the first land to which the connection terminal 2b that is the first connection terminal is joined, and the second connection. A first land that is a distance between the connection terminal 2b and the land 4b, and a distance between the connection terminal 2c and the land 4c. The height of the land 4c is set so that the difference from the second distance is smaller than the flatness of the plurality of connection terminals 2a, 2b, 2c. In the electronic device 10 of the present embodiment, as shown in FIG. 1B, the connection terminal 2b that is close to the virtual reference plane α on the side of the joint 5 on which the light-emitting diode 1A is surface-mounted, and the reference plane The dimensional difference h ₁ with respect to the connection terminal 2c far from α is illustrated as the flatness of the connection terminal 2c. In order to set the virtual reference plane α, for example, the tip of each connection terminal 2a, 2b, 2c of the light emitting diode 1A on the wiring board 3 side is measured by various image recognition means. Next, the virtual reference plane α can be set by calculating from a plurality of points measured by the computer using the least square method.

  More specifically, the electronic device 10 of the present embodiment is configured by mounting a light emitting diode 1A as an electronic component 1 on the surface 3a side of the flat wiring board 3 using a bonding portion 5 made of solder. Yes.

  As shown in FIG. 2, the light-emitting diode 1A has, for example, an LED chip 12 housed on the inner bottom surface 11a side of the concave portion of the surface mount package 11 made of epoxy resin (see FIG. 2A). ). In the light emitting diode 1 </ b> A, plate-like connection terminals 2 a and 2 b are projected from both side surfaces 11 b and 11 b side of the surface mount package 11 as electrode terminals for feeding power to the LED chip 12. Further, a convex lens 13 made of a translucent resin is provided on the light emitting surface side of the light emitting diode 1A so as to cover the LED chip 12 (see FIG. 2B). The light emitting diode 1A is used for heat dissipation, in which the LED chip 12 is mounted on the connection terminal 2c protruding from the outer bottom surface 11c side of the surface mount package 11 opposite to the light emitting surface, and heat generated by driving the LED chip 12 is radiated to the outside. (Refer to FIG. 2B and FIG. 2C).

  Here, in the light emitting diode 1A, as shown in FIG. 2B, the connection terminals 2a and 2b, which are electrode terminals for feeding, protrude from the central portion of the side surface 11b of the surface mount package 11. In the light emitting diode 1 </ b> A, a connection terminal 2 c that is a terminal for heat dissipation protrudes from the outer bottom surface 11 c of the surface mount package 11. The light-emitting diode 1A is bent close to the height of the connection terminal 2c by bending the plate-like connection terminals 2a and 2b protruding from both side surfaces 11b of the surface-mount package 11 so that the light-emitting diode 1A can be surface-mounted on the wiring board 3. ing.

  In general, the light emitting diode 1A includes a flat connection terminal 2a, 2b that serves as an electrode terminal for supplying power to the LED chip 12, and the LED chip 12 mounted on the wiring board 3 side. The shape, such as thickness and size, is different from the connection terminal 2c for heat dissipation, which becomes a heat sink that dissipates the heat of the chip 12. A part of the connection terminal 2 c for heat dissipation protrudes from the outer bottom surface 11 c side of the surface-mount package 11, and most of the connection terminals 2 c are accommodated in the surface-mount package 11. In the light emitting diode 1A used in the electronic device 10 of this embodiment, the internal temperature of the surface mount package 11 is more efficiently lowered than the connection terminals 2a and 2b, which are electrode terminals for power feeding formed in a flat plate shape. The connection terminal 2c, which is a terminal for radiating heat, is formed in a thick and large area to improve heat transfer efficiency.

  For this reason, the light emitting diode 1A is defined so that the connection terminals 2a and 2b serving as power supply electrode terminals and the connection terminal 2c serving as a heat dissipation terminal have different heights from the one surface 3a of the wiring board 3. .

In the light emitting diode 1A used in the electronic device 10 of the present embodiment, as illustrated in FIG. 1B, the power supply connection terminal 2b used as a reference for the height position from the one surface 3a of the wiring board 3 is virtually used. The first connection terminal is made to coincide with the reference plane α. In addition, the light emitting diode 1A uses, as the second connection terminal, the connection terminal 2c protruding from the outer bottom surface 11c of the surface mount package 11 having a height position different from the connection terminal 2b from the one surface 3a. That is, the connection terminal 2b of the light-emitting diode 1A will protrude by h ₁ from the outer bottom surface 11c of the surface mount package 11 on the wiring board 3 side to be surface mounted than the connection terminals 2c projecting. The connection terminal 2a of the light emitting diode 1A is also bent so as to protrude to the wiring board 3 side at the same height as the connection terminal 2b. In FIG. 1B, the reference of the flatness of the connection terminal 2b is indicated by the reference plane α, but the reference may be not only a planar shape but also a linear shape or a dot shape.

  The electronic device 10 according to the present embodiment is a first land 4b to which a connection terminal 2b serving as a power supply electrode terminal serving as a first connection terminal is joined, and a heat dissipation terminal serving as a second connection terminal. The wiring board 3 includes a second land 4c to which the connection terminal 2c is bonded.

Here, the difference between the first distance (not shown) that is the distance between the connection terminal 2b and the land 4b and the second distance that is the distance between the connection terminal 2c and the land 4c is a plurality of the above-described differences. connection terminals 2a, 2b, and the height of the land 4c to be smaller to form high as h ₃ compared to land 4b than flatness 2c.

  Such a wiring board 3 is one on which the electronic component 1 can be surface-mounted, and the land 4a, 4b is formed from an insulating base 31 and a metal material formed on the one surface 3a side of the insulating base 31. , 4c. A wiring pattern (not shown) is appropriately extended from the lands 4a, 4b, and 4c to the lands 4a, 4b, and 4c of the wiring board 3, and a wiring circuit and a heat dissipation path of the electronic component 1 can be configured. Examples of the wiring pattern material include copper and aluminum.

  The lands 4a, 4b, and 4c of the wiring board 3 used in the electronic device 10 of the present embodiment can be changed in height by thickening by plating or solder leveler processing, thinning by polishing or etching, and the like. . The height of the land 4c serving as the second land is set to be smaller than the flatness of the connection terminals 2a, 2b, 2c designed in advance of the light emitting diode 1A.

  In order to change the height of the land 4c, for example, a mask pattern made of resin is formed on the one surface 3a side of the wiring board 3 except for the land 4c. Electrode plating is performed by immersing an electrode electrically connected to the wiring pattern extending from the land 4c in an electrolytic solution. The land 4c of the wiring board 3 can be increased in height by individually passing a current through the land 4c and changing the time and amount of the plating process.

  Further, in order to form the land 4b of the wiring board 3 at a predetermined height, for example, the lands 4a and 4b to be lowered in height may be partially removed by etching. Further, in order to adjust the heights of the lands 4a, 4b, 4c of the wiring board 3, the lands 4a, 4b, 4c having different heights are appropriately combined with partial removal or partial thickening of the lands 4a, 4b, 4c. 4b and 4c can also be formed.

  The electronic device 10 may be appropriately provided with a surface reflection layer (not shown) that reflects light emitted from the light emitting diode 1 </ b> A as the electronic component 1 on the one surface 3 a side of the wiring board 3. The layer can also be used as a mask pattern during the plating process for increasing the height of the land 4c. Thus, the wiring board 3 used in the electronic device 10 of this embodiment can form lands 4a, 4b, and 4c having different heights from the one surface 3a side. The heights of the lands 4a, 4b, 4c provided on the one surface 3a side of the wiring board 3 are different depending on the flatness of the connection terminals 2a, 2b, 2c of the light emitting diode 1A as the electronic component 1.

  In the electronic device 10 of the present embodiment, the heat radiation land 4c of the wiring board 3 connected through the joint portion 5 is formed in a shape substantially similar to the planar shape of the connection terminal 2c facing the land 4c. I am letting. That is, in the electronic device 10, if the planar shape of the connection terminal 2c in the light emitting diode 1A is, for example, a circular shape as shown in FIG. 2C, the planar shape of the land 4c may be formed in a substantially circular shape. preferable. Further, the planar shape of the heat radiation land 4c is similar to the planar shape of the heat radiation connection terminal 2c, and it is more preferable that the land 4c is formed in a smaller size.

  When the planar shape of the land 4c is similar to the planar shape of the connection terminal 2c, the arrangement of the light emitting diode 1A is shifted due to the surface tension of the solder as the solder melts during the formation of the joint portion 5. Can be prevented and the self-alignment effect can be enhanced.

  Further, the land 4c of the wiring board 3 used in the electronic device 10 of the present embodiment is appropriately designed depending on the electrical connection structure inside the surface mount package 11 of each connection terminal 2a, 2b, 2c in the light emitting diode 1A. May be changed. The land 4c of the wiring board 3 may have, for example, a structure in which the connection terminal 2c serving as a heat radiating terminal is electrically independent from the LED chip 12 and does not constitute a wiring circuit, or a connection terminal serving as a power supply electrode terminal. It is good also as a structure of the wiring circuit electrically joined to 2a, 2b.

  When the connection terminal 2c of the light emitting diode 1A is electrically independent from the connection terminals 2a and 2b without forming a wiring circuit, the electronic device 10 has a land 4c connected to the connection terminal 2c via the junction 5. May be connected to a wiring pattern extending from either one of the lands 4a and 4b. As a result, the electronic device 10 can transfer heat from the LED chip 12 to the wiring pattern connected to the other lands 4a and 4c from the land 4c, thereby enhancing the heat dissipation effect.

  In addition, when the connection terminal 2c is electrically connected to one of the connection terminals 2a and 2b to form a wiring circuit, the electronic device 10 is separate from the connection terminals 2a and 2b having the same polarity as the wiring circuit. An electrically independent land 4c may be provided separately. Thereby, the electronic device 10 uses a tester or the like to connect the wiring pattern extending from the lands 4a and 4b to which the connecting terminals 2a and 2b having the same polarity as the connecting terminals 2a and 2b are connected to the wiring pattern extending from the land 4c. Can be used to confirm the continuity of the joint 5. Therefore, the electronic device 10 of the present embodiment is formed between the connection terminal 2c and the land 4c of the wiring board 3, and even if it is the joint portion 5 that is difficult to see directly under the surface mount package 11, the joint portion It becomes possible to inspect whether 5 is electrically joined appropriately.

The wiring board 3, on the other table surface opposite to the first surface 3a of the wiring pattern is formed of the insulating base 31, the heat dissipation layer made of a metal material such as copper foil (not shown) provided May be. The heat dissipation layer may be thermally connected to a land 4c that dissipates heat generated in the LED chip 12 of the light emitting diode 1A and a through hole (not shown) penetrating the wiring board 3. As a result, the electronic device 10 transmits the heat of the light emitting diode 1A from the heat radiation layer through the connection terminal 2c, the junction 5 connected to the connection terminal 2c, the land 4c connected via the junction 5, and the through hole. It is possible to dissipate heat.

  In the electronic device 10 according to the present embodiment, the connection terminals 2a, 2b, and 2c of the light emitting diode 1A and the lands 4a, 4b, and 4c of the wiring board 3 are arranged via solder and soldered by a reflow soldering method. It can be surface-mounted.

  The electronic device 10 can connect the connection terminals 2a, 2b, and 2c of the electronic component 1 to the lands 4a, 4b, and 4c of the wiring board 3 by the joint portion 5 made of solder by a reflow soldering method. Here, the electronic device 10 is soldered to the flux on the lands 4a, 4b, 4c of different heights of the wiring board 3 formed in advance in accordance with the connection terminals 2a, 2b, 2c having different flatnesses of the electronic component 1. Cream solder mixed with particles is printed by solder printing. The connection terminals 2a, 2b, 2c of the electronic component 1 are arranged on the lands 4a, 4b, 4c of the wiring board 3 on which cream solder is formed on the one surface 3a side.

  Thereafter, the cream solder is melted by exposing the one surface 3a side of the wiring board 3 on which the electronic component 1 is disposed to hot air, and then the joint 5 is formed by cooling the molten solder to form the electronic device 10. it can. The formation of the joint portion 5 in the electronic device 10 is not necessarily performed by a reflow method using hot air, and can be performed by manual soldering or soldering by laser irradiation.

The electronic device 10 of the present embodiment includes a first distance that is a distance between a connection terminal 2b that is a first connection terminal and a land 2b that is a first land, a connection terminal 2c that is a second connection terminal, the difference between the distance Hanaredea Ru second distance between the land 4c serving as a second land, the connection terminals 2a of the light-emitting diode 1A, 2b, set the height of the land 4c so as to be smaller than the flatness of 2c By doing so, it is possible to further improve the connection reliability of the joint portion 5 made of solder without correcting the shape of the connection terminals 2a and 2b of the light emitting diode 1A. Further, in the electronic device 10 of the present embodiment, the thickness of the junction 5 formed between the connection terminals 2a, 2b, 2c and the lands 4a, 4b, 4c is substantially constant, and the light emitting diode 1A is attached to the wiring board 3. Surface mounting is possible. That is, in the electronic device 10 of the present embodiment, the amount of solder used for forming the joint portion 5 made of solder is set to each connection terminal even though the flatness of the connection terminals 2a, 2b, and 2c of the light emitting diode 1A is different. 2a, 2b, 2c can be substantially equal.

  Therefore, the electronic device 10 can substantially equalize the strength of each joint portion 5 that joins the light emitting diode 1A and the wiring board 3. The electronic device 10 can suppress the partial damage of the bonding portion 5 even when stress is applied to each bonding portion 5 that connects the light emitting diode 1A and the wiring board 3, and can further improve reliability. .

  In the electronic device 10 according to the present embodiment, the light emitting diode 1A is exemplified as the electronic component 1, but the electronic component 1 is not limited to the light emitting diode 1A. The electronic component 1 may be, for example, a light emitting diode 1A or a power transistor in which connection terminals 2a, 2b, and 2c having different flatness are determined, various ICs formed in a chip shape, and the like.

  In the electronic device 10 shown in FIG. 1 of the present embodiment, one light emitting diode 1A is mounted on the wiring board 3 as the electronic component 1, but the number of the electronic components 1 is not limited to this and is appropriately set. Can be increased. Further, different types of electronic components 1 may be mounted. In this case, each electronic component 1 is electrically connected in series, parallel, or series-parallel as appropriate using a wiring pattern extending from lands 4a, 4b, 4c formed on one surface 3a of wiring board 3. What is necessary is just to connect.

(Embodiment 2)
The electronic device 10 of the present embodiment has the same configuration as that of the electronic device 10 of the first embodiment, and the connection terminals 2a and 2b, which are power supply electrode terminals in the light emitting diode 1A shown in FIG. Instead of using the connection terminal 2c, which is a heat dissipation terminal, as the second connection terminal, the connection terminal 2c, which is the heat dissipation terminal in the light emitting diode 1A, is used as shown in FIG. The connection terminal 2a, 2b, which is a power supply electrode terminal, is used as the second connection terminal. In addition, about the structure similar to FIG. 1, the same number is attached | subjected and description is abbreviate | omitted.

A light emitting diode 1 </ b> A that is an electronic component 1 shown in FIG. 3A used in the electronic device 10 of this embodiment includes an LED chip 12 housed in a surface-mount package 11. The electronic device 10 of the present embodiment is directed to the first connecting terminal 2c from the outer bottom surface 11c side is a terminal for radiation for radiating heat of the protruding LED chip 12 to the outside of the surface mount package 11 and the connection terminals. In the electronic device 10 of the present embodiment, the second connection terminals are connection terminals 2a and 2b that are electrode terminals for feeding power to the LED chip 12 protruding from the surface mount package 11 to the side surface 11b.

In the electronic device 10 according to the present embodiment, the plurality of lands 4a, 4b, and 4c include a land 4c that serves as a first land to which a connection terminal 2c that serves as a first connection terminal is joined, and a second connection terminal. A land 4b that is a second land to which the connection terminal 2b is joined, and a first distance that is a distance between the connection terminal 2c and the land 4c, and a distance between the connection terminal 2b and the land 4b. The height of the second land 4b is set so that the difference from the second distance is smaller than the flatness of the plurality of connection terminals 2a, 2b, 2c. In the electronic device 10 of the present embodiment, as shown in FIG. 3A, the connection terminal 2c having a low height from the virtual reference plane α on the side of the joint 5 on which the light emitting diode 1A is surface-mounted, and the reference the height from the plane α illustrates the dimensional difference h ₂ between the high connection terminal 2b as the flatness of the connection terminal 2b. In addition, in the light emitting diode 1A of FIG. 3A, the connection terminal 2c is illustrated so as to coincide with the reference plane α.

In addition, the difference between the first distance (not shown) that is the distance between the connection terminal 2c and the land 4c and the second distance that is the distance between the connection terminal 2b and the land 4b is the plurality of the above-described plural distances. connection terminals 2a, 2b, illustrates that a formed by formed higher by h ₄ compared to land 4c height of the land 4b to be smaller than the flatness of 2c in FIG. 3 (b).

  As a result, in the electronic device 10 of the present embodiment, the thickness of the junction 5 formed between the connection terminals 2b and 2c and the lands 4b and 4c is substantially constant, and the light emitting diode 1A is surface-mounted on the wiring board 3. It becomes possible.

  In particular, the light emitting diode 1A used in the electronic device 10 of the present embodiment has a connection terminal 2c serving as a heat radiating terminal for radiating heat from the LED chip 12 inside the light emitting diode 1A to the surface of the wiring board 3. The reference is the height position from 3a.

Therefore, when the electronic device 10 is surface-mounted with the light emitting diode 1 </ b> A on the one surface 3 a side of the wiring board 3, the electronic device 10 is a junction 5 formed between the connection terminal 2 c of the light emitting diode 1 </ b> A and the land 4 c of the wiring board 3. The required amount of solder can be controlled by the height of the connection terminal 2c. That is, in the electronic device 10 of the present embodiment, there is a possibility that the height at which the connection terminal 2c is joined varies depending on the joining state of the connection terminals 2a and 2b, which are power supply electrode terminals, from the electronic device 10 of the first embodiment. Can also be reduced. Therefore, in the electronic device 10 of this embodiment, the light emitting diode 1A and the wiring board 3 can be joined by the joining portion 5 made of solder with a controlled amount of solder with better controllability. The electronic device 10 according to the present embodiment can further increase the connection area of the bonding portion 5 formed between the connection terminal 2c and the land 4c, thereby further stabilizing the bonding. Thereby, the electronic device 10 of the present embodiment can also stably dissipate heat from the light emitting diode 1 </ b> A from the connection terminal 2 c of the light emitting diode 1 </ b> A to the wiring substrate 3 side through the joint portion 5.

  In the electronic device 10 of the present embodiment, it is possible to further increase the bonding reliability of the bonding portion 5 made of solder without correcting the shape of the connection terminals 2a, 2b, and 2c in the light emitting diode 1A.

(Embodiment 3)
The electronic device 10 shown in FIG. 4 of the present embodiment has the same configuration as that of the electronic device 10 shown in FIG. 1 of the first embodiment, and is a light emitting device having connection terminals 2a, 2b, and 2c with flatness designed in advance. Instead of using the diode 1A as the electronic component 1, the electronic component 1 having a different flatness of the connection terminals 2d and 2e due to unintended deformation of the connection terminals 2d and 2e is different. In addition, about the structure similar to FIG. 1, the same number is attached | subjected and description is abbreviate | omitted.

  The electronic device 10 shown in FIG. 4 of the present embodiment includes an electronic component 1 having a plurality of connection terminals 2d and 2e, and a plurality of lands 4d and 4e on one surface 3a side on which the electronic component 1 is surface-mounted. And the connection terminals 2d and 2e respectively have lands 4d and 4e and joints 5 joined by soldering.

Here, the electronic component 1 shown in FIG. 5 used in the electronic device 10 of this embodiment has a semiconductor element (not shown) housed inside a rectangular parallelepiped surface-mount package 11. The semiconductor element is electrically connected to the flat connection terminal 2d through a conductive wire such as a gold wire. In the electronic component 1, a plurality (eight in this case) of plate-like connection terminals 2 d are projected at equal intervals from the both side surfaces 11 b and 11 b of the rectangular parallelepiped surface-mount package 11. Electronic components 1, align the height of the tip portion of the connection terminals 2d is bent to the wiring board 3 side so as to be surface mounted processed to connection terminal 2d protruding from the central portion of the side surface 11b of the surface mount package 11 Formed.

  By the way, in the electronic component 1 that has been made thinner, the connection terminal 2d is thinner and the strength of the connection terminal 2d tends to be lower. For this reason, some of the connection terminals 2 e may be deformed by contacting the mounting jig before the electronic component 1 is surface-mounted on the wiring board 3. The deformed connection terminal 2e has different flatnesses of the connection terminals 2d and 2e of the electronic component 1.

  The electronic component 1 used in the electronic device 10 of the present embodiment includes a first connection terminal 2d in which the plurality of connection terminals 2d and 2e serve as a reference for the height position from the one surface 3a of the wiring board 3, The first connection terminal 2d includes a second connection terminal 2e having a different height from the one surface 3a (see FIG. 4B).

  Further, in the electronic device 10 of the present embodiment, the plurality of lands 4d and 4e include a land 4d serving as a first land to which a connection terminal 2d serving as a first connection terminal is joined, and a second connection terminal. A land 4e that is a second land to which the connection terminal 2e is joined, and a first distance that is a distance between the connection terminal 2d and the land 4d, and a distance between the connection terminal 2e and the land 4e. The height of the land 4e is set so that the difference from the second distance is smaller than the flatness of the plurality of connection terminals 2e and 2d.

That is, in the electronic device 10 of the present embodiment, as shown in FIG. 4B, the connection terminal 2 d having a low height from the one surface 3 a of the wiring substrate 3 on which the electronic device 1 is surface-mounted, and the wiring substrate 3 A dimensional difference h ₅ from the connection terminal 2e having a high height from the one surface 3a is caused by the deformation of the connection terminal 2e.

Further, in the electronic device 10 of the present embodiment, as shown in FIG. 4C, a first distance (not shown) that is the distance between the connection terminal 2d and the land 4d, the connection terminal 2e, and the land 4e. the difference of a plurality of connection terminals 2d described above, only h ₆ the height of the land 4e compared to land 4d so as to be smaller than the flatness of 2e formed higher the second distance is the distance between the doing.

  The electronic device 10 according to the present embodiment has a surface on which the electronic component 1 having the connection terminals 2d and 2e having different flatness is disposed after the solder paste is solder-printed on the lands 4d and 4e of the wiring board 3 having different heights. It is formed by mounting.

  In the electronic device 10 of the present embodiment, in the electronic component 1 in which the deformation of the connection terminals 2d and 2e is caused by an external force or the like, the flatness of the connection terminal 2e to be joined and the position of the connection terminal 2e are not determined in advance. Therefore, in the electronic device 10 of the present embodiment, in the manufacturing process of the electronic device 10, after the connection terminals 2 d and 2 e of the electronic component 1 are grasped by the image recognition means, the flatness of the connection terminal 2 e and the position of the connection terminal 2 e are obtained. The height of each land 4d, 4e may be adjusted appropriately.

  Thereby, the electronic device 10 according to the present embodiment does not require follow-up soldering to the wiring board 3 in which the thickness of the joint portion 5 becomes unstable without correcting the shape of the connection terminals 2d and 2e of the electronic component 1. be able to.

  Next, a description will be given of a process of surface-mounting the electronic component 1 having different flatness of the connection terminals 2d and 2e used in the electronic device 10 of the present embodiment and the wiring board 3 having the lands 4d and 4e having different heights. To do. A process of forming cream solder on the lands 4d and 4e having different heights of the wiring board 3 will be described with reference to FIG.

  The electronic device 10 is, for example, a computer memory holding means (for example, EEPROM) in which the positions and flatness of the connection terminals 2c and 2d in the electronic component 1 shown in FIG. 4B are connected in advance to the image recognition processing device. Remember me.

  Corresponding to the connection terminals 2d and 2e having different flatnesses of the electronic component 1 shown in FIG. 4B, the lands 4d and 4e are polished based on the flatness information held in the memory holding means of the computer. Thus, the wiring board 3 provided with lands 4d and 4e having different heights as shown in FIG. 4C is formed.

  Next, the electronic device 10 according to the present embodiment prints solder to be the joint portion 5 in the electronic device 10 on the lands 4d and 4e of the wiring board 3 by solder printing. That is, the wiring board 3 in the electronic device 10 of the present embodiment solder-prints the cream solder 23 on the lands 4d and 4e using the metal mask 21 as shown in FIG. The metal mask 21 includes through holes 21d and 21e in accordance with the arrangement and size of the lands 4d and 4e on which the cream solder 23 is printed on the one surface 3a side of the wiring board 3. The metal mask 21 has a concave portion 21c that is recessed in a step shape on one side 21b side of the metal mask 21 by half etching. On the other surface 21a side of the metal mask 21, a flat surface is formed except for the through holes 21d and 21e.

The metal mask 21 is arranged with the one surface 21 b side facing the one surface 3 a side of the wiring board 3. As a result, the metal mask 21 is in contact with the protruding surface on the one surface 21 b side of the metal mask 21 with the land 4 d having a low height from the one surface 3 a of the wiring substrate 3. Further, in the metal mask 21, a land 4e having a height from the one surface 3a of the wiring board 3 is in contact with the recess 21c. As a result, the metal mask 21 is formed with the recesses 21c having different depths according to the height difference between the land 4d as the first land and the land 4e as the second land on the one surface 21b side . Will be.

  The cream solder 23 is printed on the lands 4e and 4d of the wiring board 3 by scraping the cream solder 23 disposed on the other surface 21a of the metal mask 21 with a squeegee 22 made of a material such as urethane rubber, metal or plastic. (Refer to the white arrow in FIG. 6) The cream solder 23 is filled in the through holes 21 d and 21 e of the metal mask 21. By removing the metal mask 21 from the one surface 3a side of the wiring board 3, the solder paste 23 can be transferred to the lands 4d and 4e of the wiring board 3 to perform solder printing.

  The half-etched metal mask 21 used for forming the electronic device 10 of the present embodiment includes a recess 21c whose thickness is partially changed on the one surface 21b side of the metal mask 21. Here, when it is desired to change the solder amount of the cream solder 23 corresponding to the height of the connection terminals 2d and 2e of the electronic component 1, the metal mask 21 is dug at a depth corresponding to the height of the lands 4d and 4e. Half-etching process is performed. The metal mask 21 can be appropriately adjusted in the amount of cream solder 23 printed on the lands 4d and 4e of the wiring substrate 3 by being subjected to half-etching.

  The metal mask 21 for forming the cream solder 23 on the lands 4d and 4e of the wiring board 3 used in the electronic device 10 of the present embodiment has a recess 21c on the one surface 3a side of the wiring board 3 on which the cream solder 23 is printed. It has. Therefore, the metal mask 21 used for manufacturing the electronic device 10 of the present embodiment has a metal mask 21 and a land 4d having a low height as compared with a case where solder printing is performed using a metal mask having a uniform thickness. It is possible to prevent the solder amount of the cream solder 23 from becoming unstable by suppressing the generation of a gap therebetween.

The electronic device 10 of this embodiment, when the cream solder 23 on the wiring board 3 solder printing solder paste height from one surface 3a of the wiring board 3 is solder printed on low land 4d 23 solder amount of the through-hole 21d of the metal mask 21 to be higher as compared to the high land 4e from one surface 3a of the wiring board 3, is formed a shape of 21e and the recess 21c.

  Thereby, on the lands 4d and 4e of the wiring board 3 on which the cream solder 23 is printed, the height G of the cream solder 23d on the low land 4d as shown in FIG. The amount of solder is adjusted to be higher than the height E of the cream solder 23e of the high land 4e. Similarly, in the metal mask 21, the opening diameter of the through hole 21d is made smaller than the opening diameter of the through hole 21e, and the width F of the cream solder 23d on the low land 4d is set to the width of the cream solder 23e on the high land 4e. The amount of solder is adjusted to be narrower than D.

  As a result, the electronic device 10 according to the present embodiment allows the land of the wiring board 3 to be used even when the difference in height between the adjacent lands 4d and 4e is large or the interval between the lands 4d and e having different heights is narrow. By suppressing the generation of a gap between 4d and 4e and the metal mask 21 by stepping the recess 21c of the metal mask 21, the cream solder 23 can be printed with a stable amount of solder. .

Thereby, the electronic device 10 of the present embodiment can be manufactured with high productivity. Further, the electronic device 10 performs solder printing using the metal mask 21 in which the through holes 21d and 21e corresponding to the thickness of the lands 4d and 4e are formed on the wiring board 3 provided with the lands 4d and 4e having different thicknesses. This makes it possible to suppress the consumption of the squeegee 22. For this reason, it is possible to reduce the strict management of the production loss and replacement time associated with the replacement of the squeegee 22.

  Needless to say, the solder printing on the wiring board 3 used in the electronic device 10 is used not only in the present embodiment but also in the electronic device 10 according to the first and second embodiments described above.

  The electronic device 10 according to this embodiment is configured so that the electronic component 1 having a structure in which the flatness of the plurality of connection terminals 2d and 2e is different from each other on the wiring board 3 without correcting the shape of the connection terminals 2d and 2e of the electronic component 1. By joining the lands 4d and 4e with solder, the joint reliability of the joint portion 5 made of solder can be further increased. In addition, the electronic device 10 of the present embodiment is manufactured by joining the electronic component 1 having a structure in which the flatness of the plurality of connection terminals 2d and 2e is different from each of the lands 4d and 4e of the wiring board 3 by soldering. Soldering can be reliably performed at a low cost.

  The electronic device 10 of this embodiment formed in this way further improves the bonding reliability of the bonding portion 5 made of solder without correcting the shape of the connection terminal 2d in the electronic component 1 or performing additional soldering to the wiring board 3. It becomes possible.

DESCRIPTION OF SYMBOLS 1 Electronic component 1A Light emitting diode 2a, 2b, 2c, 2d, 2e Connection terminal 3 Wiring board 3a One surface 4a, 4b, 4c, 4d, 4e Land 5 Junction part 10 Electronic device 11 Surface mount type package 21 Metal mask 22 Squeegee

Claims (4)

An electronic device comprising an electronic component having a surface-mount package and a wiring board having a plurality of lands on one surface to which a plurality of connection terminals of the electronic component are joined by joints made of solder. Because
The plurality of connection terminals are a first connection terminal used as a reference of a height position from the one surface of the wiring board, and the first connection terminal is different in a height position from the one surface. 2 connection terminals,
The plurality of lands have a first land to which the first connection terminal is joined and a height of the first land from which the second connection terminal is joined differ from the first surface . A second distance that is a distance between the first connection terminal and the first land, and a second distance that is a distance between the second connection terminal and the second land. The height of the second land is set so that the difference from the distance is smaller than the flatness of the plurality of connection terminals.   The electronic component includes an LED chip housed in the surface mount type package, and the first connection terminal is an electrode terminal for supplying power to the LED chip protruding from the surface mount type package to the side surface side. The second connection terminal is a heat radiating terminal that protrudes from the outer bottom surface side of the surface-mount package and dissipates heat of the LED chip to the outside. Electronic equipment.   The electronic component includes an LED chip housed in the surface-mount package, and the first connection terminal projects from the outer bottom surface side of the surface-mount package to radiate heat of the LED chip to the outside. 2. The heat dissipation terminal, and the second connection terminal is an electrode terminal for feeding power to the LED chip protruding from the surface-mount package toward the side surface. Electronic equipment. 4. The method of manufacturing an electronic device according to claim 1, wherein the first land and the second land are formed on one surface side by half-etching when the joint portion is formed. 5. A metal mask formed with recesses having different depths according to the difference in land height is disposed on the wiring board with the one surface side of the metal mask facing the one surface side of the wiring board. Providing the solder to each of the first land and the second land from through holes provided in the plurality of recesses of the metal mask by solder printing using the metal mask;
A step of joining the first connection terminal and the second connection terminal of the electronic component to the first land and the second land, respectively, by a joint made of solder by a reflow soldering method. A method for manufacturing an electronic device.

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