JP2015082649A - Semiconductor element, and method of adhering solder to terminal included in semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor element, and a method of adhering solder to a terminal included in the semiconductor element.SOLUTION: A semiconductor element comprises: a main body part 10; and a plurality of terminals 20 attached and fixed to the main body part 10. Each of the plurality of terminals 20 is immersed into a solder bath 150 in which molten solder is stored, and then, raised from the solder bath 150, and thereby, the molten solder is adhered to the terminal 20. Each terminal 20 includes: a leg part 21 extending in a direction separated from the main body part; and a connector 22 provided at an end part of the leg part 21, and immersed into the solder bath 150. The leg part included in each of the plurality of terminals 20 has a shape extending in a direction approaching the solder bath 150, and a length of at least one of the leg parts included in the plurality of respective terminals 20 is different from that of the leg part included in the other terminal 20. The connector 22 is formed in an annular shape having a gap by notching a part thereof.

Description

  The present invention relates to a semiconductor element having a main body part and a plurality of terminals fixedly attached to the main body part, and a method for attaching solder to the terminals of the semiconductor element.

  Conventionally, as shown in Patent Document 1, for example, a holding portion is integrally formed on the upper end portion of a lead portion of a terminal, and after inserting and connecting an electronic component element to the holding portion, the electronic component element and the holding portion are covered with resin A method for manufacturing an electronic component has been proposed. The electronic component element is inserted and connected to the holding portion after a solder plating process for forming a thin solder film on the terminal holding portion and the lead portion is performed.

JP S63-126255 A

  As described above, in the method of manufacturing an electronic component disclosed in Patent Document 1, a solder film is formed on the holding portion. As a method for forming this solder film, a method is conceivable in which, after the holding portion is immersed in a solder bath, the holding portion is pulled up from the solder bath to allow excess solder to flow down. In the case of this method, when the lengths of the lead portions of the plurality of terminals are different, the amount of solder attached to each lead portion is different. Therefore, when the terminal is pulled up from the solder bath, the solder flows down from the lead portion toward the holding portion, which may cause excess solder to adhere to the holding portion. If the electronic component element is inserted into a region (hereinafter, simply referred to as a hole) surrounded by the annular inner ring surface if the holding portion has a ring shape, the above-mentioned should have penetrated. The hole is filled with solder. Therefore, it may be difficult to connect the external terminal and the terminal by inserting the electronic component element (external terminal) into the hole.

  In view of the above problems, an object of the present invention is to provide a semiconductor element in which the connection between the external terminal and the terminal is suppressed and a method for attaching solder to the terminal of the semiconductor element. .

  In order to achieve the above object, the present invention includes a main body (10) and a plurality of terminals (20) fixedly attached to the main body, and the solder (40) in which each of the plurality of terminals is melted. A semiconductor element in which molten solder is attached to a terminal by being dipped in the solder bath (150) in which the molten metal is stored, and the terminal extends in a direction away from the main body. (21) and a connection portion (22) provided at the end of the foot and immersed in the solder bath, and each foot having a plurality of terminals has a shape extending in a direction approaching the solder bath. And at least one of the legs of each of the plurality of terminals is different in length from the legs of the other terminals, and the connecting part is notched partially so as to form a ring with a gap. Features.

  When the connection portion (22) has an annular shape without a gap, when the connection portion (22) is pulled up from the solder bath (150), the solder (melted in a film shape by surface tension on its inner surface (22c)) ( 40) adheres. When the lengths of the plurality of foot portions (21) are equal, only the plurality of connection portions (22) are immersed in the solder bath (150) without immersing each of the plurality of foot portions (21) in the solder bath (150). can do. Therefore, even when the solder (40) is attached to the inner surface (22c) of the connection portion (22) when the terminal (20) is pulled up from the solder bath (150), the foot (21 ) Is prevented from flowing, and thereby the strength of the film is suppressed from increasing. Therefore, the film can be broken by the flow of the film-like solder (40) by its own weight.

  However, when the length of the foot (21) is different for design reasons such as the shape of the case (120) for housing the semiconductor element (100) and the arrangement of the external terminal (130) connected to the terminal (20), At least one foot (21) must be immersed in the solder bath (150) and the amount of solder (40) adhering to the foot (21) is different. In addition, the time during which each of the plurality of connection portions (22) is immersed in the solder bath (150) is also different. Therefore, when the connecting portion (22) is pulled up from the solder bath (150), the solder (40) attached to the foot portion (21) flows into the solder (40) attached to the connecting portion (22) in a film shape, This increases the strength of the membrane. Then, the solder (40) is solidified before the film is broken by the flow due to its own weight, and the region surrounded by the inner surface (22c) of the connection portion (22) that should have penetrated (hereinafter, simply referred to as a hole). Is filled with solder (40). Therefore, the external terminal (130) and the terminal (20) cannot be connected by passing the external terminal (130) through the hole of the connection portion (22).

  On the other hand, in this invention, the connection part (22) has comprised the cyclic | annular form which has a gap by notching part. Therefore, when the connecting portion (22) is pulled up after being immersed in the solder bath (150), the solder (40) attached to the inner surface (22c) of the connecting portion (22) in the form of a film by surface tension is removed from the gap. The flow generated when the solder (40) to be filled flows down into the solder bath (150) due to its own weight (hereinafter referred to as the first flow), and the solder (40) to fill the gap minimizes its surface area. It can be broken by the flow (hereinafter referred to as the second flow) generated when trying to do so. Thereby, it is suppressed that the hole of the connection part (22) is filled with the solder (40), and it is possible to prevent the external terminal (130) and the terminal (20) from being connected. Furthermore, since the excess solder (40) is returned to the solder bath (150) by the above-described flow, the thickness of the solder (40) attached to the connection portion (22) is adjusted.

  The gap is located in the lateral direction perpendicular to the direction approaching the solder bath. According to this, when the connection portion (22) is immersed in the solder bath (150), the first flow and the second flow are different from the configuration in which the gap is provided at a position facing the solder bath (150). It is suppressed that the flow cancels out. The first flow proceeds toward the solder bath (150), and the second flow proceeds toward the center of the connection portion (22). In the case of the comparative configuration described above, the first flow proceeds in a direction approaching the solder bath (150), and the second flow proceeds in a direction away from the solder bath (150). As a result, the two flows cancel each other. On the other hand, in the case of the above configuration, the first flow proceeds in the lateral direction, and the second flow proceeds in a direction approaching the solder bath (150). Therefore, the two flows are prevented from canceling each other as compared with the comparative configuration, and the film is broken by the stress generated by the two flows. As a result, the hole of the connecting portion (22) is suppressed from being filled with the solder (40), and the external terminal (130) and the terminal (20) can be prevented from being connected. And the thickness of the solder (40) adhering to a connection part (22) is adjusted.

  The connecting portion has two end faces (22a, 22b) facing each other through a gap, and at least one of the two end faces is outside the center (CP) of the region surrounded by the inner face (22c) of the connecting portion. The gap is inclined so that the width of the gap along the direction around the center of the connection portion increases as it goes to. According to this, at least one of the two end faces (22a, 22b) is inclined so that the width of the gap along the circumferential direction becomes narrower toward the outside from the center (CP) of the connecting portion (22). In comparison, when the connection part (22) is pulled up from the solder bath (150), the second flow generated between the two edges formed by the end faces (22a, 22b) and the outer face (22d) is promoted, and the film is broken. It becomes easy. As a result, the hole of the connecting portion (22) is suppressed from being filled with the solder (40), and the external terminal (130) and the terminal (20) can be prevented from being connected. And the thickness of the solder (40) adhering to a connection part (22) is adjusted.

  In addition, although the elements described in the claims and the means for solving the problems are attached with parentheses, the parentheses are attached to each component described in the embodiment. This is to simply show the correspondence with the elements, and does not necessarily indicate the elements themselves described in the embodiments. The description of the reference numerals with parentheses does not unnecessarily narrow the scope of the claims.

1 is a perspective view showing a schematic configuration of an ECU including a semiconductor element according to a first embodiment. It is a top view of ECU shown in FIG. It is an enlarged view of the terminal shown in FIG. It is the schematic which shows a preparation process. It is the schematic which shows an immersion process. It is the schematic which shows a raising process. It is a top view which shows the state which pulled up the terminal 1st distance from the solder bath, (a) shows the state in xy plane, (b) shows the state in yz plane. It is a top view which shows the state which pulled up the terminal 2nd distance from the solder bath, (a) shows the state in xy plane, (b) shows the state in yz plane. It is a top view which shows the state which pulled up the terminal 3rd distance from the solder bath, (a) shows the state in xy plane, (b) shows the state in yz plane. It is a top view which shows the state which pulled up the terminal 4th distance from the solder bath, (a) shows the state in xy plane, (b) shows the state in yz plane. It is a top view which shows the state which pulled up the terminal 5th distance from the solder bath, (a) shows the state in xy plane, (b) shows the state in yz plane. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part. It is a top view which shows the modification of a connection part.

Hereinafter, an embodiment when the present invention is applied to an ECU will be described with reference to the drawings.
(First embodiment)
The semiconductor element according to this embodiment will be described with reference to FIGS. In order to clarify the configuration, in FIG. 1, the semiconductor element 100, the heat sink 110, and the external terminal 130 surrounded by the case 120 are indicated by solid lines, and the solder 40 is omitted in FIGS. 1 and 2. In FIG. 2, the external terminal 130 and the terminal 20 not connected to the external terminal 130 are omitted, and in FIG. 4 to 6, elements unnecessary for explaining the adhesion of the molten solder 40 to the terminals 20 are omitted. In each drawing, the solder 40 attached to the terminal 20 is indicated by hatching. In particular, in FIGS. 7 to 11, the solder 40 attached to the terminal 20 due to surface tension or the like is also hatched.

  Hereinafter, the three directions orthogonal to each other are referred to as an x direction, a y direction, and a z direction. A plane defined by the x direction and the y direction is an xy plane, a plane defined by the y direction and the z direction is a yz plane, and a plane defined by the z direction and the x direction is a zx plane. It shows. The x direction corresponds to the lateral direction described in the claims, and the y direction is a direction along the direction approaching the solder bath described in the claims. In the adhesion method in which the molten solder 40 is adhered to the terminal 20 described later, the x direction is along the vertical direction, and the yz plane is along the horizontal direction.

  As shown in FIG. 1, the semiconductor element 100 is one of the components of the ECU 200. The ECU 200 includes the semiconductor element 100 described above, a heat sink 110 that radiates heat generated in the semiconductor element 100, and a case 120 that houses the semiconductor element 100 and the heat sink 110. The semiconductor element 100 has a terminal 20, and this terminal 20 is connected to an external terminal 130 extending from the motor winding via a solder 40. The ECU 200 includes two semiconductor elements 100, and each of the two semiconductor elements 100 is thermally connected to the heat sink 110.

  The semiconductor element 100 includes a main body 10 and a plurality of terminals 20 attached and fixed to the main body 10. Although not shown, the main body 10 includes a chip on which a power element is formed and a protection unit that covers and protects the chip. One end of the terminal 20 is electrically connected to the chip, and is covered and protected by a protection unit. The other end of the terminal 20 is exposed to the outside from the protective portion and connected to the external terminal 130 via the solder 40. The protective part has a rectangular shape and has two surfaces each having three different areas. The main surface having the largest area in the protection portion is thermally connected to the heat sink 110 along the xz plane. And the end surface with the smallest area in a protection part follows the xy plane, and the terminal 20 is exposed outside from the end surface.

  The part of the terminal 20 exposed to the outside from the protection part includes a foot part 21 extending in a direction away from the main body part 10 and a connection part 22 provided at an end of the foot part 21 and immersed in a solder bath. Have. As shown in FIG. 1, the foot 21 is bent to form an L shape in the yz plane. And as shown in FIG. 2, the foot | leg part 21 has comprised the shape extended in the y direction. As shown in FIGS. 1 and 2, the case 120 has a cylindrical shape, and the foot portion 21 of each of the plurality of terminals 20 has a length corresponding to the shape of the case 120. For this reason, at least one of the foot portions 21 of each of the plurality of terminals 20 has a length in the y direction different from the foot portions 21 of the other terminals 20.

  As shown in FIG. 3, the connection portion 22 has a ring shape (hook shape) having a gap when a part thereof is notched. The gap is located in the x direction, and the connecting portion 22 opens in the x direction. The connecting portion 22 has two end faces 22a and 22b facing each other through a gap, an inner face 22c connected to each of the end faces 22a and 22b, an outer face 22d connected to the inner face 22c via each of the end faces 22a and 22b, Have The upper end surface 22a has a shape along the zx plane, and the lower end surface 22b has an inclined shape so that the width of the gap increases as it goes outward from a region surrounded by the inner surface 22c (hereinafter simply referred to as a hole). Is made. More specifically, the lower end surface 22b is inclined so that the width of the gap along the direction around the center CP increases from the center CP of the hole (marked with x in FIG. 3) toward the outside. More specifically, the lower end surface 22b is inclined so that the width of the gap along the y direction increases from the center CP toward the left side of the drawing along the x direction from the center CP. With this configuration, the gap width d1 (the width d1 of the outer opening surface) between the connecting end of the lower end surface 22b and the outer surface 22d and the connecting end of the upper end surface 22a and the outer surface 22d is the inner surface 22c of the lower end surface 22b. And a gap width d2 (width d2 of the inner opening surface) in the y direction between the connection end of the upper end surface 22a and the connection end of the upper end surface 22a with the inner surface 22c.

  The inner surface 22c is divided into a first inner surface 22e and a second inner surface 22f by a bottom line BL (circle mark shown in FIG. 3) closest to the solder bath 150. The bottom line BL is located farthest from the foot 21 and extends along the z direction. The first inner surface 22e is connected to the upper end surface 22a and has a surface shape that continuously approaches from the upper end surface 22a toward the bottom line BL. The second inner surface 22f is connected to the lower end surface 22b and has a surface shape that continuously approaches from the lower end surface 22b toward the bottom line BL. The first inner surface 22e is continuously connected to the upper end surface 22a in the x direction, and the second inner surface 22f is discontinuously connected to the lower end surface 22b.

  Next, an attachment method for attaching the molten solder 40 to the terminal 20 will be described with reference to FIGS. First, as shown in FIG. 4, the semiconductor element 100 is placed in the solder bath 150 so that the extending direction of the legs 21 of each of the plurality of terminals 20 is orthogonal to the liquid level of the solder bath 150 in which the molten solder 40 is stored. Is placed above. The above is the preparation process.

  After the preparation step, as shown in FIG. 5, the plurality of terminals 20 are brought close to the solder bath 150, and the connection portions 22 of the plurality of terminals 20 are immersed in the solder bath 150. At this time, all the connecting portions 22 are immersed in the solder bath 150 while avoiding adhesion of the molten solder 40 to the shortest foot portion 21. The above is an immersion process.

  After the dipping process, all the connecting portions 22 dipped in the solder bath 150 are pulled up from the solder bath 150 as shown in FIG. In this way, the molten solder 40 is attached to each of the connection portions 22. The above is the pulling process.

  After the pulling process, the connecting portion 22 to which the solder 40 is attached is left on the liquid surface of the solder bath 150 for a predetermined time. By doing so, the solder 40 that adheres to the inner surface 22c of the connecting portion 22 in a film shape due to surface tension flows when the solder 40 tries to flow down into the solder bath 150 due to its own weight, and the solder that fills the gap. 40 breaks down due to the flow that occurs when trying to minimize its own surface area. Thus, the thickness of the solder 40 attached to the connecting portion 22 is adjusted by returning the excess solder 40 to the solder bath 150. The above is the thickness adjusting step.

  The flow of the solder 40 in the pulling process and the thickness adjusting process will be described with reference to FIGS. As shown in FIG. 7, after the terminal 20 is immersed in the solder bath 150, the connecting portion 22 is pulled up from the liquid surface of the solder bath 150 by a first distance so that the upper end surface 22a is exposed to the outside. At this time, since the inner surface 22 c is in the solder bath 150, the hole and the gap of the connection portion 22 are filled with the solder 40.

  Next, as shown in FIG. 8, the connecting portion 22 is pulled up by the second distance so that the entire lower end surface 22b is exposed to the outside. At this time, the solder 40 filling the gap is separated from the solder 40 stored in the solder bath 150. In the solder 40 that fills the gap, a force that tries to flow down to the solder bath 150 by its own weight and a force that minimizes the surface area (contact area with the external atmosphere) are generated. As described above, the gap width increases from the center CP toward the outside. Therefore, the solder 40 filling the gap tends to flow toward the center CP. In other words, the solder 40 filling the gap tends to flow from the outer opening surface toward the inner opening surface. At this time, as shown in FIG. 8A, the surface tension of the solder 40 closing the outer opening surface is cut, and the solder 40 filling the gap flows toward the inner opening surface.

  Next, as shown in FIG. 9, the connecting portion 22 is pulled up by the third distance so that the entire connecting portion 22 is exposed to the outside. At this time, along with the flow of the solder 40 for minimizing the surface area, the solder 40 filling the hole flows to flow down to the solder bath 150 by its own weight.

  Further, as shown in FIG. 10, the connecting portion 22 is pulled up by the fourth distance. The flow described above is continued even when the distance is raised from the third distance to the fourth distance, but there is still excess solder 40 in the hole. Therefore, the thickness of the solder 40 attached to the surface of the connection portion 22 is still nonuniform.

  However, as shown in FIG. 11, the connecting portion 22 is pulled up to the fifth distance and stays for a predetermined time. In this way, excess solder 40 in the hole is caused to flow down by the above-described flow, and the thickness of the solder 40 attached to the surface of the connection portion 22 is made uniform.

  Next, functions and effects of the semiconductor element 100 according to this embodiment will be described. Unlike the semiconductor element 100 shown in the present embodiment, when the connection portion 22 has a ring shape without a gap, when the connection portion 22 is pulled up from the solder bath 150, the inner surface 22c of the connection portion 22 is formed into a film by surface tension. The molten solder 40 adheres to the surface. In this configuration, when the lengths of the plurality of foot portions 21 are equal, only the plurality of connection portions 22 can be immersed in the solder bath 150 without immersing each of the plurality of foot portions 21 in the solder bath 150. Therefore, when the terminal 20 is pulled up from the solder bath 150, even if the solder 40 adheres to the inner surface 22c of the connecting portion 22 in a film shape, the solder 40 attached to the foot portion 21 is prevented from flowing to the film. As a result, an increase in the strength of the film is suppressed. Therefore, the film can be broken by the flow of the film-like solder 40 due to its own weight.

  However, if the length of the foot 21 is different for design reasons such as the shape of the case 120 that houses the semiconductor element 100 and the arrangement of the external terminals 130, at least one foot 21 must be immersed in the solder bath 150. Instead, the amount of solder 40 attached to the foot 21 is different. Further, the time during which each of the plurality of connecting portions 22 is immersed in the solder bath 150 is also different. Therefore, when the connecting portion 22 is pulled up from the solder bath 150, the solder 40 attached to the foot portion 21 flows into the solder 40 attached to the connecting portion 22 in a film shape, thereby increasing the strength of the film. Then, the solder 40 is solidified before the film is broken by the flow due to its own weight, and the hole of the connecting portion 22 that should have been penetrated is filled with the solder 40. Therefore, the external terminal 130 and the terminal 20 cannot be connected by passing the external terminal 130 through the hole of the connection portion 22.

  On the other hand, in this embodiment, the connection part 22 has comprised the cyclic | annular form which has a gap by notching part. Therefore, when the connecting portion 22 is pulled up after being immersed in the solder bath 150, the solder 40 adhered to the inner surface 22c of the connecting portion 22 in a film shape by surface tension is used, and the solder 40 filling the gap has a weight of the solder bath. The flow that occurs when it flows down to 150 (hereinafter referred to as the first flow) and the flow that occurs when the solder 40 filling the gap minimizes its surface area (hereinafter referred to as the second flow). Can be destroyed by. As a result, the hole of the connecting portion 22 is suppressed from being filled with the solder 40, and the external terminal 130 and the terminal 20 can be prevented from being connected. Furthermore, since the excess solder 40 is returned to the solder bath 150 by the above-described flow, the thickness of the solder 40 attached to the connection portion 22 is adjusted.

  The gap is located in the x direction. According to this, when the connecting portion 22 is immersed in the solder bath 150, unlike the configuration in which the gap is located in the y direction (configuration in which the gap is provided facing the solder bath 150), the first It is suppressed that the flow and the second flow cancel each other. The first flow proceeds toward the solder bath 150 and the second flow proceeds toward the center of the connection portion 22. In the case of the comparative configuration described above, the first flow proceeds in a direction approaching the solder bath 150, and the second flow proceeds in a direction away from the solder bath 150. As a result, the two flows cancel each other. On the other hand, in the case of the above configuration, the first flow proceeds in the x direction and the second flow proceeds in the y direction. Therefore, the two flows are prevented from canceling each other as compared with the comparative configuration, and the film is broken by the stress generated by the two flows. As a result, the hole of the connecting portion 22 is suppressed from being filled with the solder 40, and the external terminal 130 and the terminal 20 are prevented from being connected. And the thickness of the solder 40 adhering to the connection part 22 is adjusted.

  The gap is inclined so that the width of the gap increases from the center CP toward the outside. According to this, when the connection portion 22 is pulled up from the solder bath 150, the gap between the two end portions formed by the end surfaces 22a and 22b and the outer surface 22d is smaller than the configuration in which the gap width is narrowed toward the outside from the center CP. The second flow generated at the (outer opening surface) is promoted, and the membrane is easily broken. As a result, the hole of the connecting portion 22 is suppressed from being filled with the solder 40, and the external terminal 130 and the terminal 20 can be prevented from being connected. And the thickness of the solder 40 adhering to the connection part 22 is adjusted.

  The first inner surface 22e has a surface shape that continuously approaches from the upper end surface 22a toward the bottom line BL, and the second inner surface 22f has a surface shape that continuously approaches from the lower end surface 22b toward the bottom line BL. For example, when at least one of the inner surfaces 22e and 22f discontinuously approaches the bottom line BL, that is, when the inner surfaces 22e and 22f have a surface shape along a direction away from the bottom line BL, the distance from the solder bath 150 is increased. The solder 40 formed in a film shape on the connecting portion 22 is broken. For this reason, the breaking speed of the film-like solder 40 becomes slow, and there is a possibility that unintended solder 40 is left behind in the connection portion 22. On the other hand, in the case of the above configuration, the solder 40 formed in a film shape on the connection portion 22 is broken so as to approach the solder bath 150. Therefore, it is possible to suppress unintended solder 40 from being left in the connection portion 22 as compared with the above-described comparative configuration.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the present embodiment, an example in which the semiconductor element 100 is applied to the ECU 200 is shown. However, the semiconductor element 100 only needs to attach the solder 40 to the connection portion 22 by immersing the connection portions 22 of the terminals 20 having different lengths in the solder bath 150, and the application target is not limited.

  In the present embodiment, an example in which the main body unit 10 includes a chip on which a power element is formed and a protection unit that covers and protects the chip. However, the main body 10 is not limited to the above example, and may be any one as long as one end of the terminal 20 is fixed.

  An example is shown in which the foot 21 is bent to form an L shape in the yz plane. However, the foot portion 21 does not have to be bent, and may have a portion extending in the y direction.

  In the present embodiment, the upper end surface 22a has a shape along the zx plane, and the lower end surface 22b has an example in which the width of the gap is increased toward the outside from the hole. . However, the shape of the end faces 22a and 22b is not limited to the above example.

  For example, as shown in FIG. 12, it is possible to adopt a configuration in which the lower end surface 22b has a shape along the zx plane and the gap width is constant. Further, as shown in FIG. 13, the upper end surface 22a has a shape along the zx plane, and the lower end surface 22b has an inclined shape so that the width of the gap becomes narrower toward the outside from the hole. Good.

  Although not particularly mentioned in the present embodiment, an example is shown in which the curvatures of the inner surfaces 22e and 22f are indefinite as shown in FIG. However, as shown in FIG. 14, the curvature of each of the inner surfaces 22e and 22f may be constant, and the contour line formed by the inner surface 22c in the xy plane may be circular.

  In the present embodiment, the first inner surface 22e has a surface shape that continuously approaches from the upper end surface 22a toward the bottom line BL, and the second inner surface 22f has a surface shape that continuously approaches from the lower end surface 22b toward the bottom line BL. An example is shown. However, as shown in FIG. 15, the first inner surface 22e has a surface shape discontinuously approaching from the upper end surface 22a toward the bottom line BL, and the second inner surface 22f is discontinuous from the lower end surface 22b toward the bottom line BL. The surface shape which approaches may be comprised.

  In the present embodiment, an example in which the gap is located in the x direction is shown. However, the gap may be positioned in the y direction as shown in FIGS. In FIG. 16, the gap is located above the bottom line BL, and in FIGS. 17 to 19, the bottom line BL is located in the gap. 17 to 19, the outer surface 22d is inclined so that the outer diameter of the portion facing the end surfaces 22a and 22b in the x direction becomes narrower as the solder bath 150 is approached. 17 and 19, the end surfaces 22a and 22b are discontinuously connected to the inner surfaces 22e and 22f. In FIG. 18, the end surfaces 22a and 22b are continuously connected to the inner surfaces 22e and 22f. 17 and 18, the width in the x direction of the gap between the end faces 22a and 22b is constant, and in FIG. 19, the width in the x direction of the gap increases from the center toward the outside. Although the bottom line BL is not illustrated in FIGS. 17 to 19, the above-described bottom line BL is a line farthest from the foot 21 on the inner surface 22 c when the connection part 22 is annular.

In the present embodiment, an example is shown in which the lower end surface 22b is inclined so that the width of the gap increases as it goes out of the hole. However, as shown in FIGS. 20 to 22, it is possible to adopt a configuration in which the lower end surface 22 b has a shape along the zx plane. 20 to 22, the shape of the upper end surface 22 a is different. In FIG. 20, the upper end surface 22 a is inclined so that the width of the gap increases as it goes out of the hole. In FIG. 21, the upper end surface 22 a is z. It has a shape along the -x plane. In FIG. 22, the upper end surface 22a is inclined so that the width of the gap becomes narrower as it goes out of the hole.
In the present embodiment, an example in which the first inner surface 22e is continuously connected to the upper end surface 22a is shown. However, as shown in FIGS. 23 and 24, a configuration in which the first inner surface 22e is discontinuously connected to the upper end surface 22a may be employed. In FIG. 23, the width of the gap in the y direction is constant, and in FIG. 24, the width of the gap in the y direction is indefinite. Specifically, the width of the gap gradually increases from the hole toward the outside.

  Although not particularly mentioned in the present embodiment, as shown in FIG. 3, an example is shown in which the connection angle between the lower end surface 22b and the second inner surface 22f is an acute angle. However, as shown in FIG. 25, a configuration in which the connection angle between the lower end surface 22b and the second inner surface 22f is an obtuse angle may be employed. In addition, as shown in FIG. 23, the above-described configuration in which the connection angle is a right angle can be employed. This connection angle relationship is the same for the upper end surface 22a and the first inner surface 22e.

  In the present embodiment, an example in which the bottom line BL is along the z direction is shown. However, the shape of the bottom line BL is not limited to the above example, and any shape that conforms to the zx plane can be adopted as appropriate.

  In the present embodiment, an example in which all the connection portions 22 are immersed in the solder bath 150 while avoiding adhesion of the molten solder 40 to the shortest foot portion 21 in the dipping process is shown. However, the molten solder 40 may be attached to all the foot portions 21.

DESCRIPTION OF SYMBOLS 10 ... Main-body part 20 ... Terminal 21 ... Leg part 22 ... Connection part 40 ... Solder 100 ... Semiconductor element 150 ... Solder bath

Claims (5)

A main body (10) and a plurality of terminals (20) attached and fixed to the main body, each of the plurality of terminals being immersed in a solder bath (150) in which molten solder (40) is stored. A semiconductor element to which the molten solder is attached to the terminal by being pulled up from the solder bath after being
The terminal includes a foot portion (21) extending in a direction away from the main body portion, and a connection portion (22) provided at an end portion of the foot portion and immersed in the solder bath,
Each of the plurality of terminals has a leg extending in a direction approaching the solder bath,
At least one of the legs of each of the plurality of terminals has a different length from the legs of the other terminals,
The semiconductor device according to claim 1, wherein a part of the connection portion is notched to form a ring having a gap.   The semiconductor device according to claim 1, wherein the gap is located in a lateral direction orthogonal to a direction approaching the solder bath. The connecting portion has two end faces (22a, 22b) facing each other through the gap,
At least one of the two end faces is configured such that the width of the gap along the direction around the center of the connection portion increases as it goes outward from the center (CP) of the region surrounded by the inner surface of the connection portion. The semiconductor element according to claim 1, wherein the semiconductor element is inclined toward the surface. The connecting portion has two end faces (22a, 22b) facing each other through the gap,
The inner surface (22c) of the connecting portion includes a first inner surface (22e) that smoothly connects one of the two end surfaces and the bottom line (BL) closest to the solder bath, the other of the two end surfaces, and the bottom line. A second inner surface (22f) for smoothly connecting the two,
The first inner surface has a surface shape that continuously approaches the bottom line from one of the two end faces toward the bottom line,
4. The semiconductor element according to claim 2, wherein the second inner surface has a surface shape that continuously approaches the bottom line from the other of the two end faces toward the bottom line. 5. . An attachment method for attaching the melted solder (40) to the terminal (20) of the semiconductor element (100) according to any one of claims 1 to 4,
A dipping step in which the plurality of terminals are brought close to the solder bath (150) in which molten solder is stored, and the connection portions (22) of the plurality of terminals are immersed in the solder bath;
After the dipping step, a pulling step of pulling up each of the plurality of terminals from the solder bath,
After the pulling step, the solder attached to the solder is allowed to stay on the liquid surface of the solder bath for a predetermined time, so that the solder attached to the inner surface (22c) of the connecting part in a film form due to surface tension, Breaking due to the flow that occurs when the solder that fills the gap flows down into the solder bath due to its own weight, and the flow that occurs when the solder that fills the gap tries to minimize its surface area; A thickness adjusting step of adjusting the thickness of the solder attached to the connecting portion by returning the excess solder to the solder bath.

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