The present disclosure relates to a semiconductor device.
Various configurations have been proposed for semiconductor devices with semiconductor elements. As an example of such a semiconductor device, there exists a semiconductor device in which a semiconductor element mounted on a die pad is connected to a lead with a wire and these are covered with a sealing resin. In such a semiconductor device, the reverse surface of the die pad may be exposed from the sealing resin to serve as a reverse surface terminal. In such a case, to prevent the die pad from falling off through the reverse surface of the sealing resin, the die pad is formed with an internal reverse surface facing the same side as the reverse surface and covered with the sealing resin. JP-A-2021-27116 discloses a semiconductor device in which a semiconductor element is mounted on the obverse surface of a mount portion of a first lead and the reverse surface of the mount portion is exposed from the sealing resin to serve as a reverse terminal. In the semiconductor device, the first lead includes a mount-portion reverse-side recess that is recessed from the reverse surface of the mount portion in the z direction.
In such a semiconductor device, the sealing resin may separate from the die pad due to the thermal stress caused by the difference in coefficient of linear expansion between the die pad and the sealing resin. When the separation progresses, stress may concentrate on an end of the die pad, causing a crack in the sealing resin. In particular, the internal reverse surface is connected to an end of the die pad and has a small area, and therefore, can easily crack when separation of the sealing resin occurs at the internal reverse surface.
The following describes preferred embodiments of the present disclosure with reference to the drawings.
A semiconductor device A10 according to a first embodiment of the present disclosure is described below based on
The semiconductor device A10 shown in these figures is a device to be surface-mounted on a circuit board of various equipment. The use and function of the semiconductor device A10 are not limited. The package type of the semiconductor device A10 is DFN (Dual Flatpack No-leaded). Note that the package type of the semiconductor device A10 is not limited to DFN. The semiconductor device A10 is generally rectangular as viewed in the thickness direction. For the convenience of description, the thickness direction (plan-view direction) of the semiconductor device A10 is defined as a z direction, the direction (the horizontal direction in
The leads 1 to 3 are electrically connected to the semiconductor element 6. The leads 1 to 3 are made of a metal, and preferably made of Cu or Ni, an alloy of these, or a 42 alloy, for example. The material of the leads 1 to 3 is not limited. The leads 1 to 3 are made from a lead frame formed by subjecting a metal plate to a stamping process, for example. The thickness of the leads 1 to 3 is not particularly limited and may be about 0.05 to 0.3 mm, for example. In the present embodiment, the thickness is about 0.25 mm.
As shown in
The lead 1 supports the semiconductor element 6 and includes an obverse surface 11, a reverse surface 12, an internal reverse surface 13, an internal connection surface 16, an internal end surface 17, and connection end surfaces 14 and 15.
The obverse surface 11 and the reverse surface 12 face away from each other in the z direction. The obverse surface 11 faces the z2 side in the z direction. The obverse surface 11 is the surface on which the semiconductor element 6 is mounted. In the present embodiment, the obverse surface 11 is generally rectangular and includes a portion protruding toward the y2 side in the y direction and portions protruding toward opposite sides in the x direction. Each of these protruding portions partially protrudes from the sealing resin 8 to be exposed. The number of such protruding portions is not limited. The reverse surface 12 is exposed from the sealing resin 8 to serve as a reverse terminal. In the present embodiment, the reverse surface 12 is generally rectangular and includes a portion protruding toward the y2 side in the y direction and portions protruding toward opposite sides in the x direction. Each of these protruding portions partially protrudes from the sealing resin 8 to be exposed. The number of such protruding portions is not limited.
The internal reverse surface 13 faces the same side as the reverse surface 12 in the z direction (the z1 side in the z direction) and is covered with the sealing resin 8. The internal reverse surface 13 is connected to the internal connection surface 16 and the internal end surface 17. In the present embodiment, as shown in
As shown in
The irregular portion 19 includes a plurality of recesses 191. As shown in
The plurality of recesses 191 include recesses 191a, recesses 191b, recesses 191c, and recesses 191d. The recesses 191a are arranged at equal intervals along the y direction at a location closest to the reverse surface 12 (the x1 side in the x direction in
The recesses 191 are approximately the same in dimension L3 (see
The internal connection surface 16 is generally perpendicular to the reverse surface 12 and the internal reverse surface 13 and connected to the reverse surface 12 and the internal reverse surface 13. The internal connection surface 16 is flat and covered with the sealing resin 8. The internal end surface 17 is generally perpendicular to the obverse surface 11 and the internal reverse surface 13 and connected to the obverse surface 11 and the internal reverse surface 13. The internal end surface 17 is covered with the sealing resin 8.
The connection end surfaces 14 and 15 are perpendicular to the obverse surface 11 and the reverse surface 12 and connected to the obverse surface 11 and the reverse surface 12. The connection end surfaces 14 and 15 are exposed from the sealing resin 8. There exists one connection end surface 14, and it faces the y2 side in the y direction. The connection end surface 14 is connected to the portion of the obverse surface 11 that protrudes toward the y2 side in the y direction and the portion of the reverse surface 12 that protrudes toward the y2 side in the y direction. In the present embodiment, the connection end surface 14 is formed with a recess recessed toward the y1 side in the y direction and extending in the z direction. There exist two connection end surfaces 15, with one of the connection end surfaces 15 facing the x1 side in the x direction while the other facing the x2 side in the x direction. The connection end surface facing the x1 side in the x direction is connected to the portion of the obverse surface 11 that protrudes toward the x1 side in the x direction and the portion of the reverse surface 12 that protrudes toward the x1 side in the x direction. The connection end surface 15 facing the x2 side in the x direction is connected to the portion of the obverse surface 11 that protrudes toward the x2 side in the x direction and the portion of the reverse surface 12 that protrudes toward the x2 side in the x direction. Each of the connection end surfaces 14 and 15 is a cut surface formed by cutting a tie bar connected to a frame part of a lead frame during the cutting step of the manufacturing process.
The configuration of the lead 1 is not limited to that described above. For example, the obverse surface 11 may be formed with a groove surrounding the semiconductor element 6 for preventing the outflow of a bonding material. The connection end surface 14 may not include the recess. The connection end surfaces 14 and 15 may not protrude from the sealing resin 8 and may be flush with the relevant surfaces of the sealing resin 8. The configuration of the lead 1 is designed as appropriate depending on the use and specifications.
The lead 2 is electrically connected to the semiconductor element 6 and includes an obverse surface 21, a reverse surface 22, an internal reverse surface 23, an internal connection surface 26, an internal end surface 27, and a connection end surfaces 24.
The obverse surface 21 and the reverse surface 22 face away from each other in the z direction. The obverse surface 21 faces the same side as the obverse surface 11 of the lead 1 (the z2 side in the z direction). The obverse surface 21 is the surface to which the connection lead 7 is bonded. The obverse surface 21 is generally rectangular in the present embodiment. A portion of the obverse surface 21 on the y1 side in the y direction protrudes from the sealing resin 8 to be exposed. The reverse surface 22 faces the same side as the reverse surface 12 of the lead 1 (the z1 side in the z direction). The reverse surface 22 is exposed from the sealing resin 8 to serve as a reverse terminal. The reverse surface 22 is generally rectangular in the present embodiment.
The internal reverse surface 23 faces the same side as the reverse surface 22 in the z direction (the z1 side in the z direction) and is covered with the sealing resin 8. The internal reverse surface 23 is connected to the internal connection surface 26 and the internal end surface 27. In the present embodiment, as shown in
The internal connection surface 26 is generally perpendicular to the reverse surface 22 and the internal reverse surface 23 and connected to the reverse surface 22 and the internal reverse surface 23. The internal connection surface 26 is flat and covered with the sealing resin 8. The internal end surface 27 is generally perpendicular to the obverse surface 21 and the internal reverse surface 23 and connected to the obverse surface 21 and the internal reverse surface 23. The internal end surface 27 is covered with the sealing resin 8.
The connection end surface 24 is perpendicular to the obverse surface 21 and the reverse surface 22 and connected to the obverse surface 21 and the reverse surface 22. The connection end surface 24 is exposed from the sealing resin 8. There exits one connection end surface 24, and it faces the y1 side in the y direction. In the present embodiment, the connection end surface 24 is formed with a recess recessed toward the y2 side in the y direction and extending in the z direction. The connection end surface 24 is a cut surface formed by cutting a tie bar connected to a frame part of a lead frame during the cutting step of the manufacturing process.
The configuration of the lead 2 is not limited to that described above. For example, the connection end surface 24 may not include the recess. The connection end surface 24 may not protrude from the sealing resin 8 and may be flush with a resin side surface 833, described later, of the sealing resin 8. The configuration of the lead 2 is designed as appropriate depending on the use and specifications.
The lead 3 is electrically connected to the semiconductor element 6 and includes an obverse surface 31, a reverse surface 32, an internal reverse surface 33, an internal connection surface 36, an internal end surface 37, and a connection end surfaces 34.
The obverse surface 31 and the reverse surface 32 face away from each other in the z direction. The obverse surface 31 faces the same side as the obverse surface 11 of the lead 1 (the z2 side in the z direction). The obverse surface 31 is the surface to which the connection lead 7 is bonded. The obverse surface 31 is generally rectangular in the present embodiment. A portion of the obverse surface 31 on the y1 side in the y direction protrudes from the sealing resin 8 to be exposed. The reverse surface 32 faces the same side as the reverse surface 12 of the lead 1 (the z1 side in the z direction). The reverse surface 32 is exposed from the sealing resin 8 to serve as a reverse terminal. The reverse surface 32 is generally rectangular in the present embodiment.
The internal reverse surface 33 faces the same side as the reverse surface 32 in the z direction (the z1 side in the z direction) and is covered with the sealing resin 8. The internal reverse surface 33 is connected to the internal connection surface 36 and the internal end surface 37. In the present embodiment, as shown in
The internal connection surface 36 is generally perpendicular to the reverse surface 32 and the internal reverse surface 33 and connected to the reverse surface 32 and the internal reverse surface 33. The internal connection surface 36 is flat and covered with the sealing resin 8. The internal end surface 37 is generally perpendicular to the obverse surface 31 and the internal reverse surface 33 and connected to the obverse surface 31 and the internal reverse surface 33. The internal end surface 37 is covered with the sealing resin 8.
The connection end surface 34 is perpendicular to the obverse surface 31 and the reverse surface 32 and connected to the obverse surface 31 and the reverse surface 32. The connection end surface 34 is exposed from the sealing resin 8. There exits one connection end surface 34, and it faces the y1 side in the y direction. In the present embodiment, the connection end surface 34 is formed with a recess recessed toward the y2 side in the y direction and extending in the z direction. The connection end surface 34 is a cut surface formed by cutting a tie bar connected to a frame part of a lead frame during the cutting step of the manufacturing process.
The configuration of the lead 3 is not limited to that described above. For example, the connection end surface 34 may not include the recess. The connection end surface 34 may not protrude from the sealing resin 8 and may be flush with a resin side surface 833, described later, of the sealing resin 8. The configuration of the lead 3 is designed as appropriate depending on the use and specifications.
The semiconductor element 6 is an element that performs the electrical function of the semiconductor device A10. The type of the semiconductor element 6 is not particularly limited. In the present embodiment, the semiconductor element 6 is a diode. The semiconductor element 6 includes an element body 60, a first electrode 631, and a second electrode 632.
The element body 60 has the shape of a rectangular plate as viewed in the z direction. The element body 60 is made of a semiconductor material and is made of Si (silicon) in the present embodiment. The material of the element body 60 is not limited and may be other materials such as SiC (silicon carbide) or GaN (gallium nitride). The element body 60 has an element obverse surface 61 and an element reverse surface 62. The element obverse surface 61 and the element reverse surface 62 face away from each other in the z direction. The element obverse surface 61 faces the z2 side in the z direction. The element reverse surface 62 faces the z1 side in the z direction. The first electrode 631 is disposed on the element obverse surface 61. The second electrode 632 is disposed on the element reverse surface 62. In the present embodiment, the first electrode 631 is an anode electrode, and the second electrode 632 is a cathode electrode.
As shown in
In the present embodiment, the dimensions in the x direction and the y direction of the semiconductor element 6 are about 3 mm and relatively large for the lead 1. The area Si of the semiconductor element 6 as viewed in the z direction is about 60% of the area S2 of the lead 1 (the area of the obverse surface 11 of the lead 1) as viewed in the z direction. When the area Si is equal to or greater than 50% of the area S2, the area of the lead 1 that is in contact with the sealing resin 8 is small. In such a case, the separation of the sealing resin 8 progresses to the end of the lead 1 in a relatively short period of time, and a crack can easily occur in the sealing resin 8. Moreover, the temperature of the lead 1 tends to rise due to the heat generated by the semiconductor element 6, so that separation due to thermal stress can easily occur. In the present embodiment, however, the internal reverse surface 13 includes the irregular portion 19, so that the semiconductor device A10 suppresses the separation of the sealing resin 8 at the internal reverse surface 13.
The connection lead 7 is a plate-like conductor that connects the semiconductor element 6 and the leads 2 and 3 to each other for electrical conduction. The connection lead 7 is formed by subjecting a metal plate to a stamping process or an etching process, for example. The connection lead 7 is made of a metal, and preferably made of Cu or Al, or an alloy of these, for example. The material of the connection lead 7 is not limited. The thickness of the connection lead 7 is not particularly limited and may be about 0.08 to 0.3 mm, for example. In the present embodiment, the thickness is about 0.15 mm. The connection lead 7 is formed by bending a metal plate and includes an element connection portion 71, two lead connection portions 72, and a connecting portion 73.
The element connection portion 71, which is a portion connected to the semiconductor element 6, is generally parallel to the x-y plane and generally rectangular as viewed in the z direction. The element connection portion 71 is bonded, via a bonding material not shown, to the first electrode 631 disposed on the element obverse surface 61 of the semiconductor element 6. In the present embodiment, the bonding material is a conductive bonding material and is solder, for example. The bonding material is not limited.
The two lead connection portions 72, which are the portions connected to the lead 2 and the lead 3, are generally parallel to the x-y plane and have a rectangular shape elongated in the x direction as viewed in the z direction. Each of the lead connection portion 72 is bonded to the obverse surface 21 of the lead 2 or the obverse surface 31 of the lead 3 via a bonding material, not shown. In the present embodiment, the bonding material is a conductive bonding material and is solder, for example. The bonding material is not limited.
The connecting portion 73 connects the element connection portion 71 and the two lead connection portions 72 to each other. The connecting portion 73 is connected to the element connection portion 71 at its end on the y2 side in the y direction. The end on the y1 side in the y direction of the connecting portion 73 is separated into two sections, which are connected to different lead connection portions 72. The configuration of the connection lead 7 is not limited. Instead of the connection lead 7, other connecting members, such as bonding wires, may be used to connect the first electrode 631 of the semiconductor element 6 and the leads 2 and 3.
The sealing resin 8 covers a part of each of the leads 1, 2 and 3 and the entirety of the semiconductor element 6 and the connection lead 7. The sealing resin 8 is made of black epoxy resin, for example. The material of the sealing resin 8 is not limited. The sealing resin 8 is formed by transfer molding using a mold, for example. The method for forming the sealing resin 8 is not limited.
The sealing resin 8 includes a resin obverse surface 81, a resin reverse surface 82, and four resin side surfaces 83. The resin obverse surface 81 and the resin reverse surface 82 face away from each other in the z direction. The resin obverse surface 81 faces the z2 side in the z direction, and the resin reverse surface 82 faces the z1 side in the z direction.
Each of the four resin side surfaces 83 is connected to the resin obverse surface 81 and the resin reverse surface 82. Each resin side surface 83 faces outward in the x direction or the y direction. The four resin side surfaces 83 include a resin side surface 831, a resin side surface 832, a resin side surface 833, and a resin side surface 834. The resin side surface 831 and the resin side surface 832 face away from each other in the x direction. The resin side surface 831 is located on the x1 side in the x direction and faces the x1 side in the x direction. The resin side surface 832 is located on the x2 side in the x direction and faces the x2 side in the x direction. The resin side surface 833 and the resin side surface 834 face away from each other in the y direction. The resin side surface 833 is located on the y1 side in the y direction and faces the y1 side in the y direction. The resin side surface 834 is located on the y2 side in the y direction and faces the y2 side in the y direction. The four resin side surfaces 83 are inclined such that they come closer to each other as proceeding toward the resin obverse surface 81. That is, the sealing resin 8 is tapered such that its cross sectional area in the x-y plane decreases toward the resin obverse surface 81. Note that the shape of the sealing resin 8 shown in
As shown in
An example of a method for manufacturing the semiconductor device A10 is described below with reference to
As shown in
The lead frame making step S10 is a step for making a lead frame from a metal plate. In this step, a metal plate, which is a material of the lead frame, is first prepared (S11). The metal plate has an obverse surface and a reverse surface that face away from each other in the z direction.
Next, the metal plate is subjected to a stamping process to form the lead frame 91. First, the metal plate is subjected to punching, whereby the lead frame 91 is formed as shown in
Next, a compressing process is performed on predetermined regions R of the lead frame 91 (S13). The regions R, to which relatively dense hatching is applied in
During the compressing process, a die 95 is pressed against the region R of the lead frame 91 from the reverse surface 912 side, as shown in
As shown in
The regions R of the portions of the lead frame 91 that will become the leads 2 and 3 are also compressed and spread by the die 95 to form the internal reverse surfaces 23 and 33. However, the die 95 is not formed with an irregularity-forming part 951 at locations facing the regions R of the portions of the lead frame 91 that will become the leads 2 and 3. Therefore, no irregular portion is formed on the internal reverse surfaces 23 and 33. Note that the irregularity-forming part 951 may be pressed against the lead frame 91 from the reverse surface 912 side by lowering the die 95, with the obverse surface 911 and the reverse surface 912 of the lead frame 91 vertically inverted. The regions R are compressed by the compressing process, and the internal reverse surfaces 13, 23, and 33 are formed on the reverse surface 912 side of the lead frame 91, as shown in
Meanwhile, another lead frame 94 is prepared separately from the lead frame 91, as shown in
The die bonding step S20 is a step for bonding the semiconductor element 6 to the lead frame 91. In this step, solder paste is applied to the center of a region of the obverse surface 911 of the lead frame 91 that will become the obverse surface 11 of the lead 1. Next, the semiconductor element 6 is placed on the solder paste applied. Next, reflowing is performed to melt and then solidify the solder paste. Through the above process, the semiconductor element 6 is bonded to the lead frame 91. The method for bonding the semiconductor elements 6 in the die bonding step S20 is not limited.
The connection lead bonding step S30 is a step for bonding the connection lead 7 as shown in
The sealing step S40 is a step for forming the sealing resin 8. In this step, a resin material is hardened to form the sealing resin 8 (indicated by double dashed lines in
The cutting step S50 is a step for cutting the lead frame 91. In this step, the lead frame 91 is cut along cutting lines (indicated by single dashed lines in
The effects of the semiconductor device A10 are described below.
According to the present embodiment, the internal reverse surface 13 of the lead 1 is formed with the irregular portion 19. The irregular portion 19 includes a plurality of recesses 191. The contact area between the internal reverse surface 13 and the sealing resin 8 is increased as compared with the case where the irregular portion 19 is not formed, whereby adhesion of the sealing resin 8 to the internal reverse surface 13 is enhanced. Thus, the semiconductor device A10 is capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 13.
According to the present embodiment, the recesses 191 are arranged in a matrix. Because irregularities arranged along the y direction and irregularities arranged along the x direction are both formed, separation of the sealing resin 8 at the internal reverse surface 13 is suppressed for both the thermal stress generated in the x direction and the thermal stress generated in the y direction.
According to the present embodiment, the recesses 191 are formed by a stamping process. Therefore, the recesses 191 can be formed with more accurate arrangement, shape, and dimensions than when they are formed by a laser and when they are formed by half etching, for example. Moreover, as compared with the case where the recesses 191 are formed by other methods, the manufacturing process of the semiconductor device A10 can be simplified, so that the manufacturing time can be shortened and the manufacturing cost can be reduced.
In the present embodiment, the irregular portion 19 is formed at all of the portions of the internal reverse surface 13 that are located on opposite sides in the x direction of the reverse surface 12 and the portions of the internal reverse surface 13 that are located on opposite sides in the y direction of the reverse surface 12. However, the present disclosure is not limited to this. The internal reverse surface 13 may include a portion at which the irregular portion 19 is not formed. For example, the portion of the internal reverse surface 13 that is sufficiently far from the semiconductor element 6 may not be formed with the irregular portion 19. However, it is preferable that the irregular portion 19 is formed over the entirety of the internal reverse surface 13.
The irregular portion 19 formed on the internal reverse surface 13 of the lead 1 of the present embodiment includes a plurality of protrusions 192 instead of a plurality of recesses 191. As shown in
As shown in
In the present embodiment again, the internal reverse surface 13 of the lead 1 is formed with the irregular portion 19. The irregular portion 19 includes a plurality of protrusions 192. Thus, adhesion of the sealing resin 8 to the internal reverse surface 13 is enhanced. Thus, the semiconductor device A20 is capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 13. The semiconductor device A20 has a configuration in common with the semiconductor device A10, thereby achieving the same effect as the semiconductor device A10.
The internal reverse surface 23 of the lead 2 of the present embodiment is formed with the irregular portion 29. The internal reverse surface 33 of the lead 3 of the present embodiment is formed with the irregular portion 39. The configurations of the irregular portion 29 and the irregular portion 39 of the present embodiment are the same as that of the irregular portion 19 of the semiconductor device A10 according to the first embodiment. Note that the configurations of the irregular portion 29 and the irregular portion 39 are not limited and may be the same as those of the variations of the irregular portion 19 according to the first embodiment. The irregular portion 29 and the irregular portion 39 are formed by forming irregularity-forming parts 951 also at locations of the die 95 that face the region R of the portions of the lead frame 91 that will become the leads 2 and 3.
In the present embodiment again, the internal reverse surface 13 of the lead 1 is formed with the irregular portion 19. The irregular portion 19 includes a plurality of recesses 191. Thus, adhesion of the sealing resin 8 to the internal reverse surface 13 is enhanced. Thus, the semiconductor device A30 is capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 13. The semiconductor device A30 has a configuration in common with the semiconductor device A10, thereby achieving the same effect as the semiconductor device A10. Moreover, according to the present embodiment, the internal reverse surface 23 is formed with the irregular portion 29, and the internal reverse surface 33 is formed with the irregular portion 39. Thus, the semiconductor device A30 is also capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 23 and the internal reverse surface 33.
The semiconductor device A40 according to the present embodiment does not include the connection lead 7 and includes two wires 79 instead. One of the wires 79 is bonded to the first electrode 631 of the semiconductor element 6 and the obverse surface 21 of the lead 2. The other wire 79 is bonded to the first electrode 631 of the semiconductor element 6 and the obverse surface 31 of the lead 3. The number of wires 79 that connect the first electrode 631 and the obverse surface 21 and the number of wires 79 that connect the first electrode 631 and the obverse surface 31 are not limited to one. Each of these connections may use a plurality of wires 79. Also, the material, diameter, etc. of each wire 79 are not limited.
In the present embodiment again, the internal reverse surface 13 of the lead 1 is formed with the irregular portion 19. The irregular portion 19 includes a plurality of recesses 191. Thus, adhesion of the sealing resin 8 to the internal reverse surface 13 is enhanced. Thus, the semiconductor device A40 is capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 13. The semiconductor device A40 has a configuration in common with the semiconductor device A10, thereby achieving the same effect as the semiconductor device A10. Moreover, according to the present embodiment, preparation of the connection lead 7 is not necessary. Thus, the semiconductor device A40 is capable of simplifying the manufacturing process and reducing the manufacturing cost.
In the present embodiment, the semiconductor element 6 is a MOSFET (metal-oxide-semiconductor field-effect transistor), for example. The semiconductor element 6 may be other transistors such as an IGBT (Insulated Gate Bipolar Transistor). The semiconductor element 6 further includes a third electrode 633 disposed on the element obverse surface 61. In the present embodiment, the first electrode 631 is a source electrode, the second electrode 632 is a drain electrode, and the third electrode 633 is a gate electrode. The second electrode 632 of the semiconductor element 6 is electrically connected to the lead 1 via a bonding material. Thus, the lead 1 is electrically connected to the second electrode 632 (the drain electrode) of the semiconductor element 6 to function as a drain terminal. The first electrode 631 of the semiconductor element 6 is electrically connected to the lead 2 via a wire 79. Thus, the lead 2 is electrically connected to the first electrode 631 (the source electrode) of the semiconductor element 6 to function as a source terminal. The third electrode 633 of the semiconductor element 6 is electrically connected to the lead 3 via a wire 79. Thus, the lead 3 is electrically connected to the third electrode 633 (the gate electrode) of the semiconductor element 6 to function as a gate terminal.
In the present embodiment again, the internal reverse surface 13 of the lead 1 is formed with the irregular portion 19. The irregular portion 19 includes a plurality of recesses 191. Thus, adhesion of the sealing resin 8 to the internal reverse surface 13 is enhanced. Thus, the semiconductor device A50 is capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 13. The semiconductor device A50 has a configuration in common with the semiconductor device A10, thereby achieving the same effect as the semiconductor device A10.
In the present embodiment, the first electrode 631 and the lead 2 are electrically connected to each other via a wire 79, and the third electrode 633 and the lead 3 are electrically connected to each other via a wire 79, but the present disclosure is not limited to this. The first electrode 631 and the lead 2, as well as the third electrode 633 and the lead 3 may be electrically connected to each other via other connection members such as a connection lead.
The semiconductor element 6 is a diode in the first through the fourth embodiments, and the semiconductor element 6 is a transistor in the fifth embodiment. However, the present disclosure is not limited to these. The type of the semiconductor element 6 is not limited and may be other semiconductor elements such as an integrated circuit. Also, three leads are disposed in the first through the fifth embodiments, but the present disclosure is not limited to this. The number and arrangement position of leads are not limited and may be set as appropriate depending on the number and arrangement position of electrodes disposed on the element obverse surface 61 of the semiconductor element 6.
A semiconductor device A60 according to a sixth embodiment of the present disclosure will be described based on
The semiconductor device A60 shown in these figures is a device to be surface-mounted on a circuit board of various equipment. The use and function of the semiconductor device A60 are not limited. The package type of the semiconductor device A60 is DFN (Dual Flatpack No-leaded). Note that the package type of the semiconductor device A60 is not limited to DFN. The semiconductor device A60 is generally rectangular as viewed in the thickness direction. For the convenience of description, the thickness direction (plan-view direction) of the semiconductor device A60 is defined as a z direction, the direction (the horizontal direction in
The leads 1 to 3 are electrically connected to the semiconductor element 6. The leads 1 to 3 are made of a metal, and preferably made of Cu or Ni, an alloy of these, or a 42 alloy, for example. The material of the leads 1 to 3 are not limited. The leads 1 to 3 are made from a lead frame formed by subjecting a metal plate to a stamping process, for example. The thickness of the leads 1 to 3 is not particularly limited and may be 0.05 to 0.3 mm, for example. In the present embodiment, the thickness is about 0.25 mm.
As shown in
The lead 1 supports the semiconductor element 6 and includes an obverse surface 11, a reverse surface 12, an internal reverse surface 13, an internal connection surface 16, an internal end surface 17, and connection end surfaces 14 and 15.
The obverse surface 11 and the reverse surface 12 face away from each other in the z direction. The obverse surface 11 faces the z2 side in the z direction. The obverse surface 11 is the surface on which the semiconductor element 6 is mounted. In the present embodiment, the obverse surface 11 is generally rectangular and includes a portion protruding toward the y2 side in the y direction and portions protruding toward opposite sides in the x direction. Each of these protruding portions partially protrudes from the sealing resin 8 to be exposed. The number of such protruding portions is not limited. The reverse surface 12 is exposed from the sealing resin 8 to serve as a reverse terminal. In the present embodiment, the reverse surface 12 is generally rectangular and includes a portion protruding toward the y2 side in the y direction and portions protruding toward opposite sides in the x direction. Each of these protruding portions partially protrudes from the sealing resin 8 to be exposed. The number of such protruding portions is not limited.
The internal reverse surface 13 faces the same side as the reverse surface 12 in the z direction (the z1 side in the z direction) and is covered with the sealing resin 8. The internal reverse surface 13 is connected to the internal connection surface 16 and the internal end surface 17. In the present embodiment, as shown in
As shown in
The irregular portion 19 includes a plurality of first protrusions 193 and a plurality of first recesses 194. As shown in
The first protrusions 193 and the first recesses 194 are formed as a result of irradiating the internal reverse surface 13 with a laser. In the present embodiment, the laser scanning direction is the x direction, and the first recesses 194 thus extend in the x direction, as shown in
The dimension T1 of the height difference (see
As shown in
As shown in
The internal connection surface 16 is generally perpendicular to the reverse surface 12 and the internal reverse surface 13 and connected to the reverse surface 12 and the internal reverse surface 13. The internal connection surface 16 is covered with the sealing resin 8. The internal end surface 17 is generally perpendicular to the obverse surface 11 and the internal reverse surface 13 and connected to the obverse surface 11 and the internal reverse surface 13. The internal end surface 17 is covered with the sealing resin 8.
The connection end surfaces 14 and 15 are perpendicular to the obverse surface 11 and the reverse surface 12 and connected to the obverse surface 11 and the reverse surface 12. The connection end surfaces 14 and 15 are exposed from the sealing resin 8. There exists one connection end surface 14, and it faces the y2 side in the y direction. The connection end surface 14 is connected to the portion of the obverse surface 11 that protrudes toward the y2 side in the y direction and the portion of the reverse surface 12 that protrudes toward the y2 side in the y direction. In the present embodiment, the connection end surface 14 is formed with a recess recessed toward the y1 side in the y direction and extending in the z direction. There exist two connection end surfaces 15, with one of the connection end surfaces 15 facing the x1 side in the x direction while the other facing the x2 side in the x direction. The connection end surface facing the x1 side in the x direction is connected to the portion of the obverse surface 11 that protrudes toward the x1 side in the x direction and the portion of the reverse surface 12 that protrudes toward the x1 side in the x direction. The connection end surface 15 facing the x2 side in the x direction is connected to the portion of the obverse surface 11 that protrudes toward the x2 side in the x direction and the portion of the reverse surface 12 that protrudes toward the x2 side in the x direction. Each of the connection end surfaces 14 and 15 is a cut surface formed by cutting a tie bar connected to a frame part of a lead frame during the cutting step of the manufacturing process.
The configuration of the lead 1 is not limited to that described above. For example, the obverse surface 11 may be formed with a groove surrounding the semiconductor element 6 for preventing the outflow of a bonding material. The connection end surface 14 may not include the recess. The connection end surfaces 14 and 15 may not protrude from the sealing resin 8 and may be flush with the relevant surfaces of the sealing resin 8. The configuration of the lead 1 is designed as appropriate depending on the use and specifications.
The lead 2 is electrically connected to the semiconductor element 6 and includes an obverse surface 21, a reverse surface 22, an internal reverse surface 23, an internal connection surface 26, an internal end surface 27, and a connection end surfaces 24.
The obverse surface 21 and the reverse surface 22 face away from each other in the z direction. The obverse surface 21 faces the same side as the obverse surface 11 of the lead 1 (the z2 side in the z direction). The obverse surface 21 is the surface to which the connection lead 7 is bonded. The obverse surface 21 is generally rectangular in the present embodiment. A portion of the obverse surface 21 on the y1 side in the y direction protrudes from the sealing resin 8 to be exposed. The reverse surface 22 faces the same side as the reverse surface 12 of the lead 1 (the z1 side in the z direction). The reverse surface 22 is exposed from the sealing resin 8 to serve as a reverse terminal. The reverse surface 22 is generally rectangular in the present embodiment. The internal reverse surface 23 faces the same side as the reverse surface 22 in the z direction (the z1 side in the z direction) and is covered with the sealing resin 8. The internal reverse surface 23 is connected to the internal connection surface 26 and the internal end surface 27. In the present embodiment, as shown in
The internal connection surface 26 is generally perpendicular to the reverse surface 22 and the internal reverse surface 23 and connected to the reverse surface 22 and the internal reverse surface 23. The internal connection surface 26 is covered with the sealing resin 8. The internal end surface 27 is generally perpendicular to the obverse surface 21 and the internal reverse surface 23 and connected to the obverse surface 21 and the internal reverse surface 23. The internal end surface 27 is covered with the sealing resin 8.
The connection end surface 24 is perpendicular to the obverse surface 21 and the reverse surface 22 and connected to the obverse surface 21 and the reverse surface 22. The connection end surface 24 is exposed from the sealing resin 8. There exits one connection end surface 24, and it faces the y1 side in the y direction. In the present embodiment, the connection end surface 24 is formed with a recess recessed toward the y2 side in the y direction and extending in the z direction. The connection end surface 24 is a cut surface formed by cutting a tie bar connected to a frame part of a lead frame during the cutting step of the manufacturing process.
The configuration of the lead 2 is not limited to that described above. For example, the connection end surface 24 may not include the recess. The connection end surface 24 may not protrude from the sealing resin 8 and may be flush with a resin side surface 833, described later, of the sealing resin 8. The configuration of the lead 2 is designed as appropriate depending on the use and specifications.
The lead 3 is electrically connected to the semiconductor element 6 and includes an obverse surface 31, a reverse surface 32, an internal reverse surface 33, an internal connection surface 36, an internal end surface 37, and a connection end surfaces 34.
The obverse surface 31 and the reverse surface 32 face away from each other in the z direction. The obverse surface 31 faces the same side as the obverse surface 11 of the lead 1 (the z2 side in the z direction). The obverse surface 31 is the surface to which the connection lead 7 is bonded. The obverse surface 31 is generally rectangular in the present embodiment. A portion of the obverse surface 31 on the y1 side in the y direction protrudes from the sealing resin 8 to be exposed. The reverse surface 32 faces the same side as the reverse surface 12 of the lead 1 (the z1 side in the z direction). The reverse surface 32 is exposed from the sealing resin 8 to serve as a reverse terminal. The reverse surface 32 is generally rectangular in the present embodiment.
The internal reverse surface 33 faces the same side as the reverse surface 32 in the z direction (the z1 side in the z direction) and is covered with the sealing resin 8. The internal reverse surface 33 is connected to the internal connection surface 36 and the internal end surface 37. In the present embodiment, as shown in
The internal reverse surface 33 is formed by a stamping process in making a lead frame from a metal plate. As shown in
The internal connection surface 36 is generally perpendicular to the reverse surface 32 and the internal reverse surface 33 and connected to the reverse surface 32 and the internal reverse surface 33. The internal connection surface 36 is covered with the sealing resin 8. The internal end surface 37 is generally perpendicular to the obverse surface 31 and the internal reverse surface 33 and connected to the obverse surface 31 and the internal reverse surface 33. The internal end surface 37 is covered with the sealing resin 8.
The connection end surface 34 is perpendicular to the obverse surface 31 and the reverse surface 32 and connected to the obverse surface 31 and the reverse surface 32. The connection end surface 34 is exposed from the sealing resin 8. There exits one connection end surface 34, and it faces the y1 side in the y direction. In the present embodiment, the connection end surface 34 is formed with a recess recessed toward the y2 side in the y direction and extending in the z direction. The connection end surface 34 is a cut surface formed by cutting a tie bar connected to a frame part of a lead frame during the cutting step of the manufacturing process.
The configuration of the lead 3 is not limited to that described above. For example, the connection end surface 34 may not include the recess. The connection end surface 34 may not protrude from the sealing resin 8 and may be flush with a resin side surface 833, described later, of the sealing resin 8. The configuration of the lead 3 is designed as appropriate depending on the use and specifications.
The semiconductor element 6 is an element that performs the electrical function of the semiconductor device A60. The type of the semiconductor element 6 is not particularly limited. In the present embodiment, the semiconductor element 6 is a diode. The semiconductor element 6 includes an element body 60, a first electrode 631, and a second electrode 632.
The element body 60 has the shape of a rectangular plate as viewed in the z direction. The element body 60 is made of a semiconductor material and is made of Si (silicon) in the present embodiment. The material of the element body 60 is not limited and may be other materials such as SiC (silicon carbide) or GaN (gallium nitride). The element body 60 has an element obverse surface 61 and an element reverse surface 62. The element obverse surface 61 and the element reverse surface 62 face away from each other in the z direction. The element obverse surface 61 faces the z2 side in the z direction. The element reverse surface 62 faces the z1 side in the z direction. The first electrode 631 is disposed on the element obverse surface 61. The second electrode 632 is disposed on the element reverse surface 62. In the present embodiment, the first electrode 631 is an anode electrode, and the second electrode 632 is a cathode electrode.
As shown in
In the present embodiment, the dimensions in the x direction and the y direction of the semiconductor element 6 are about 3 mm and relatively large for the lead 1. The area S1 of the semiconductor element 6 as viewed in the z direction is about 75% of the area S2 of the lead 1 (the area of the obverse surface 11 of the lead 1) as viewed in the z direction. When the area S1 is equal to or greater than 70% of the area S2, the area of the lead 1 that is in contact with the sealing resin 8 is small. In such a case, the separation of the sealing resin 8 progresses to the end of the lead 1 in a relatively short period of time, and a crack can easily occur in the sealing resin 8. Moreover, the temperature of the lead 1 tends to rise due to the heat generated by the semiconductor element 6, so that separation due to thermal stress can easily occur. In the present embodiment, however, the internal reverse surface 13 includes the irregular portion 19, so that the semiconductor device A60 suppresses the separation of the sealing resin 8 at the internal reverse surface 13.
The connection lead 7 is a plate-like conductor that connects the semiconductor element 6 and the leads 2 and 3 to each other for electrical conduction. The connection lead 7 is formed by subjecting a metal plate to a stamping process or an etching process, for example. The connection lead 7 is made of a metal, and preferably made of Cu or Al, or an alloy of these, for example. The material of the connection lead 7 is not limited. The thickness of the connection lead 7 is not particularly limited and may be 0.08 to 0.3 mm, for example. In the present embodiment, the thickness is about 0.15 mm. The connection lead 7 is formed by bending a metal plate and includes an element connection portion 71, two lead connection portions 72, and a connecting portion 73.
The element connection portion 71, which is a portion connected to the semiconductor element 6, is generally parallel to the x-y plane and generally rectangular as viewed in the z direction. The element connection portion 71 is bonded, via a bonding material not shown, to the first electrode 631 disposed on the element obverse surface 61 of the semiconductor element 6. In the present embodiment, the bonding material is a conductive bonding material and is solder, for example. The bonding material is not limited.
The two lead connection portions 72, which are the portions connected to the lead 2 and the lead 3, are generally parallel to the x-y plane and have a rectangular shape elongated in the x direction as viewed in the z direction. Each of the lead connection portion 72 is bonded to the obverse surface 21 of the lead 2 or the obverse surface 31 of the lead 3 via a bonding material, not shown. In the present embodiment, the bonding material is a conductive bonding material and is solder, for example. The bonding material is not limited.
The connecting portion 73 connects the element connection portion 71 and the two lead connection portions 72 to each other. The connecting portion 73 is connected to the element connection portion 71 at its end on the y2 side in the y direction. The end on the y1 side in the y direction of the connecting portion 73 is separated into two sections, which are connected to different lead connection portions 72. The configuration of the connection lead 7 is not limited.
Instead of the connection lead 7, other connecting members, such as bonding wires, may be used to connect the first electrode 631 of the semiconductor element 6 and the leads 2 and 3.
The sealing resin 8 covers a part of each of the leads 1, 2 and 3 and the entirety of the semiconductor element 6 and the connection lead 7. The sealing resin 8 is made of black epoxy resin, for example. The material of the sealing resin 8 is not limited. The sealing resin 8 is formed by transfer molding using a mold, for example. The method for forming the sealing resin 8 is not limited.
The sealing resin 8 includes a resin obverse surface 81, a resin reverse surface 82, and four resin side surfaces 83. The resin obverse surface 81 and the resin reverse surface 82 face away from each other in the z direction. The resin obverse surface 81 faces the z2 side in the z direction, and the resin reverse surface 82 faces the z1 side in the z direction.
Each of the four resin side surfaces 83 is connected to the resin obverse surface 81 and the resin reverse surface 82. Each resin side surface 83 faces outward in the x direction or the y direction. The four resin side surfaces 83 include a resin side surface 831, a resin side surface 832, a resin side surface 833, and a resin side surface 834. The resin side surface 831 and the resin side surface 832 face away from each other in the x direction. The resin side surface 831 is located on the x1 side in the x direction and faces the x1 side in the x direction. The resin side surface 832 is located on the x2 side in the x direction and faces the x2 side in the x direction. The resin side surface 833 and the resin side surface 834 face away from each other in the y direction. The resin side surface 833 is located on the y1 side in the y direction and faces the y1 side in the y direction. The resin side surface 834 is located on the y2 side in the y direction and faces the y2 side in the y direction. The four resin side surfaces 83 are inclined such that they come closer to each other as proceeding toward the resin obverse surface 81. That is, the sealing resin 8 is tapered such that its cross sectional area in the x-y plane decreases toward the resin obverse surface 81. Note that the shape of the sealing resin 8 shown in
As shown in
An example of a method for manufacturing the semiconductor device A60 is described below with reference to
As shown in
The lead frame making step S10 is a step for making a lead frame from a metal plate. In this step, a metal plate, which is a material of the lead frame, is first prepared (S11). The metal plate has an obverse surface and a reverse surface that face away from each other in the z direction.
Next, the metal plate is subjected to a stamping process to form the lead frame 91 as shown in
Next, as shown in
The laser to form the irregular portion 19 is emitted as a pulsed output. The pulse output frequency is adjustable and is not limited, but is about 10 to 100 kHz, for example, and is 40 kHz in the present embodiment. The scanning speed of the laser is adjustable and is not limited, but is about 100 to 500 mm/s, for example, and is 200 mm/s in the present embodiment. In each of the first recess 194 are formed a plurality of second protrusions 195 arranged along the x-direction at intervals corresponding to the pulse output frequency and the scanning speed of the laser, and the portions between adjacent second protrusions 195 are the second recesses 196. Also, in each of the first protrusions 193 are formed a plurality of second protrusions 197 arranged along the x direction at intervals corresponding to the pulse output frequency and the scanning speed of the laser, and the portions between adjacent second protrusions 197 are the third recesses 198.
Meanwhile, another lead frame 94 is prepared separately from the lead frame 91, as shown in
The die bonding step S20 is a step for bonding the semiconductor element 6 to the lead frame 91. In this step, solder paste is applied to the center of a region of the obverse surface 911 of the lead frame 91 that will become the obverse surface 11 of the lead 1. Next, the semiconductor element 6 is placed on the solder paste applied. Next, reflowing is performed to melt and then solidify the solder paste. Through the above process, the semiconductor element 6 is bonded to the lead frame 91. The method for bonding the semiconductor elements 6 in the die bonding step S20 is not limited.
The connection lead bonding step S30 is a step for bonding the connection lead 7 as shown in
The sealing step S40 is a step for forming the sealing resin 8. In this step, a resin material is hardened to form the sealing resin 8 (indicated by double dashed lines in
The cutting step S50 is a step for cutting the lead frame 91. In this step, the lead frame 91 is cut along cutting lines (indicated by single dashed lines in
The effects of the semiconductor device A60 are described below.
According to the present embodiment, the internal reverse surface 13 of the lead 1 is formed with the irregular portion 19. The irregular portion 19 includes a plurality of first protrusions 193 and a plurality of first recesses 194. The contact area between the internal reverse surface 13 and the sealing resin 8 is increased as compared with the case where the irregular portion 19 is not formed, whereby adhesion of the sealing resin 8 to the internal reverse surface 13 is enhanced. Thus, the semiconductor device A60 is capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 13.
In the present embodiment, each of the first recesses 194 is formed with a plurality of second protrusions 195 and a plurality of second recesses 196. The contact area between the internal reverse surface 13 and the sealing resin 8 is increased as compared with the case where each first recess 194 is not formed with the second protrusions 195 and the second recesses 196, whereby adhesion of the sealing resin 8 to the internal reverse surface 13 is enhanced. Thus, the semiconductor device A60 is capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 13. Because irregularities arranged along the y direction and irregularities arranged along the x direction are both formed, separation of the sealing resin 8 at the internal reverse surface 13 is suppressed for both the thermal stress generated in the x direction and the thermal stress generated in the y direction.
In the present embodiment, each of the first protrusions 193 is formed with a plurality of second protrusions 197 and a plurality of third recesses 198. The contact area between the internal reverse surface 13 and the sealing resin 8 is increased as compared with the case where each first protrusion 193 is not formed with the second protrusions 197 and the third recesses 198, whereby adhesion of the sealing resin 8 to the internal reverse surface 13 is enhanced. Thus, the semiconductor device A60 is capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 13. Because irregularities arranged along the y direction and irregularities arranged along the x direction are both formed, separation of the sealing resin 8 at the internal reverse surface 13 is suppressed for both the thermal stress generated in the x direction and the thermal stress generated in the y direction.
In the present embodiment, all laser scanning directions are the x direction. Thus, the laser irradiation process can be simplified as compared with the case where the laser scanning direction changes.
In the present embodiment, the irregular portion 19 is formed by irradiating the internal reverse surface 13 with a pulsed laser. This makes it possible to form the second protrusions 195 and the second recesses 196 in the first recesses 194 and form the second protrusions 197 and the third recesses 198 in the first protrusions 193 while forming the first recesses 194 and the first protrusions 193.
Because the irregular portion 19 is formed by laser irradiation in the present embodiment, it is possible to form more minute irregularities in a regularly arranged manner as compared with the case where irregularities are formed in the internal reverse surface 13 by other techniques. The dimensions of the irregularities (the dimensions T1, T3, T4 and the spacings W1, W2, etc.) can be adjusted by adjusting the laser power, the pulse output frequency, the scanning speed, etc.
As shown in the second through the seventh variations, the extension direction of the first protrusions 193 and the first recesses 194 can be set freely. The respective extension directions of the first protrusions 193 and the first recesses 194 may differ depending on their locations within the irregular portion 19. The first protrusions 193 and the first recesses 194 extending in different directions may be arranged in an overlapping manner. For example, the first protrusions 193 and first recesses 194 extending in the y direction and the first protrusions 193 and first recesses 194 extending in a first direction inclined with respect to the x direction and the y direction may be arranged in an overlapping manner. Three or more types of first protrusions 193 and first recesses 194 extending in different directions may be arranged in an overlapping manner.
In the present embodiment, the irregular portion 19 is formed at all of the portions of the internal reverse surface 13 that are located on opposite sides in the x direction of the reverse surface 12 and the portions of the internal reverse surface 13 that are located on opposite sides in the y direction of the reverse surface 12. However, the present disclosure is not limited to this. The internal reverse surface 13 may include a portion at which the irregular portion 19 is not formed. For example, the portion of the internal reverse surface 13 that is sufficiently far from the semiconductor element 6 may not be formed with the irregular portion 19. However, it is preferable that the irregular portion 19 is formed over the entirety of the internal reverse surface 13.
The internal reverse surface 23 of the lead 2 of the present embodiment is formed with the irregular portion 29. The internal reverse surface 33 of the lead 3 of the present embodiment is formed with the irregular portion 39. The configurations of the irregular portion 29 and the irregular portion 39 of the present embodiment are the same as that of the irregular portion 19 of the semiconductor device A60 according to the sixth embodiment. Note that the configurations of the irregular portion 29 and the irregular portion 39 are not limited and may be the same as those of the variations of the irregular portion 19 according to the sixth embodiment. The irregular portion 29 and the irregular portion 39 are formed by laser irradiation as with the irregular portion 19.
In the present embodiment again, the internal reverse surface 13 of the lead 1 is formed with the irregular portion 19. The irregular portion 19 includes a plurality of first protrusions 193 and a plurality of first recesses 194. Thus, adhesion of the sealing resin 8 to the internal reverse surface 13 is enhanced. Thus, the semiconductor device A70 is capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 13. Also, in the present embodiment again, each of the first recesses 194 is formed with a plurality of second protrusions 195 and a plurality of second recesses 196, and each of the first protrusions 193 is formed with a plurality of second protrusions 197 and a plurality of third recesses 198. This further enhances adhesion of the sealing resin 8 to the internal reverse surface 13. Thus, the semiconductor device A70 is capable of more reliably suppressing the separation of the sealing resin 8 at the internal reverse surface 13. Because irregularities arranged along the y direction and irregularities arranged along the x direction are both formed, separation of the sealing resin 8 at the internal reverse surface 13 is suppressed for both the thermal stress generated in the x direction and the thermal stress generated in the y direction. The semiconductor device A70 has a configuration in common with the semiconductor device A60, thereby achieving the same effect as the semiconductor device A60. Also, according to the present embodiment, the internal reverse surface 23 is formed with the irregular portion 29, and the internal reverse surface 33 is formed with the irregular portion 39. Thus, the semiconductor device A70 is also capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 23 and the internal reverse surface 33.
In the present embodiment, in the step (S15) of forming the lead frame 91 during the lead frame making step, the lead frame 91 is formed by etching a metal plate. The irregular portion 19, the irregular portion 29 and the irregular portion 39 are formed by half-etching the metal plate only from the z1 side in the z direction. The boundaries between the surfaces of the lead 1 are rounded. The internal connection surface 16 is not orthogonal to the reverse surface 12 and the internal reverse surface 13 but is inclined, and the boundary with the internal reverse surface 13 is indistinct. This holds for the lead 2 and the lead 3.
In the present embodiment again, the internal reverse surface 13 of the lead 1 is formed with the irregular portion 19. The irregular portion 19 includes a plurality of first protrusions 193 and a plurality of first recesses 194. Thus, adhesion of the sealing resin 8 to the internal reverse surface 13 is enhanced. Thus, the semiconductor device A80 is capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 13. Also, in the present embodiment again, each of the first recesses 194 is formed with a plurality of second protrusions 195 and a plurality of second recesses 196, and each of the first protrusions 193 is formed with a plurality of second protrusions 197 and a plurality of third recesses 198. This further enhances adhesion of the sealing resin 8 to the internal reverse surface 13. Thus, the semiconductor device A80 is capable of more reliably suppressing the separation of the sealing resin 8 at the internal reverse surface 13. Because irregularities arranged along the y direction and irregularities arranged along the x direction are both formed, separation of the sealing resin 8 at the internal reverse surface 13 is suppressed for both the thermal stress generated in the x direction and the thermal stress generated in the y direction. The semiconductor device A80 has a configuration in common with the semiconductor device A60, thereby achieving the same effect as the semiconductor device A60.
The semiconductor device A90 according to the present embodiment does not include the connection lead 7 and includes two wires 79 instead. One of the wires 79 is bonded to the first electrode 631 of the semiconductor element 6 and the obverse surface 21 of the lead 2. The other wire 79 is bonded to the first electrode 631 of the semiconductor element 6 and the obverse surface 31 of the lead 3. The number of wires 79 that connect the first electrode 631 and the obverse surface 21 and the number of wires 79 that connect the first electrode 631 and the obverse surface 31 are not limited to one. Each of these connections may use a plurality of wires 79. Also, the material, diameter, etc. of each wire 79 are not limited.
In the present embodiment again, the internal reverse surface 13 of the lead 1 is formed with the irregular portion 19. The irregular portion 19 includes a plurality of first protrusions 193 and a plurality of first recesses 194. Thus, adhesion of the sealing resin 8 to the internal reverse surface 13 is enhanced. Thus, the semiconductor device A90 is capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 13. Also, in the present embodiment again, each of the first recesses 194 is formed with a plurality of second protrusions 195 and a plurality of second recesses 196, and each of the first protrusions 193 is formed with a plurality of second protrusions 197 and a plurality of third recesses 198. This further enhances adhesion of the sealing resin 8 to the internal reverse surface 13. Thus, the semiconductor device A90 is capable of more reliably suppressing the separation of the sealing resin 8 at the internal reverse surface 13. Because irregularities arranged along the y direction and irregularities arranged along the x direction are both formed, separation of the sealing resin 8 at the internal reverse surface 13 is suppressed for both the thermal stress generated in the x direction and the thermal stress generated in the y direction. The semiconductor device A90 has a configuration in common with the semiconductor device A60, thereby achieving the same effect as the semiconductor device A60. Moreover, according to the present embodiment, preparation of the connection lead 7 is not necessary. Thus, the semiconductor device A90 is capable of simplifying the manufacturing process and reducing the manufacturing cost.
In the present embodiment, the semiconductor element 6 is a MOSFET (metal-oxide-semiconductor field-effect transistor), for example. The semiconductor element 6 may be other transistors such as an IGBT (Insulated Gate Bipolar Transistor). The semiconductor element 6 further includes a third electrode 633 disposed on the element obverse surface 61. In the present embodiment, the first electrode 631 is a source electrode, the second electrode 632 is a drain electrode, and the third electrode 633 is a gate electrode. The second electrode 632 of the semiconductor element 6 is electrically connected to the lead 1 via a bonding material. Thus, the lead 1 is electrically connected to the second electrode 632 (the drain electrode) of the semiconductor element 6 to function as a drain terminal. The first electrode 631 of the semiconductor element 6 is electrically connected to the lead 2 via a wire 79. Thus, the lead 2 is electrically connected to the first electrode 631 (the source electrode) of the semiconductor element 6 to function as a source terminal. The third electrode 633 of the semiconductor element 6 is electrically connected to the lead 3 via a wire 79. Thus, the lead 3 is electrically connected to the third electrode 633 (the gate electrode) of the semiconductor element 6 to function as a gate terminal.
In the present embodiment again, the internal reverse surface 13 of the lead 1 is formed with the irregular portion 19. The irregular portion 19 includes a plurality of first protrusions 193 and a plurality of first recesses 194. Thus, adhesion of the sealing resin 8 to the internal reverse surface 13 is enhanced. Thus, the semiconductor device A100 is capable of suppressing the separation of the sealing resin 8 at the internal reverse surface 13. Also, in the present embodiment again, each of the first recesses 194 is formed with a plurality of second protrusions 195 and a plurality of second recesses 196, and each of the first protrusions 193 is formed with a plurality of second protrusions 197 and a plurality of third recesses 198. This further enhances adhesion of the sealing resin 8 to the internal reverse surface 13. Thus, the semiconductor device A100 is capable of more reliably suppressing the separation of the sealing resin 8 at the internal reverse surface 13. Because irregularities arranged in the y direction and irregularities arranged in the x direction are formed, separation of the sealing resin 8 at the internal reverse surface 13 is suppressed for both the thermal stress generated in the x direction and the thermal stress generated in the y direction. The semiconductor device A100 has a configuration in common with the semiconductor device A60, thereby achieving the same effect as the semiconductor device A60.
In the present embodiment, the first electrode 631 and the lead 2 are electrically connected to each other via a wire 79, and the third electrode 633 and the lead 3 are electrically connected to each other via a wire 79, but the present disclosure is not limited to this. The first electrode 631 and the lead 2, as well as the third electrode 633 and the lead 3 may be electrically connected to each other via other connection members such as a connection lead.
The semiconductor element 6 is a diode in the sixth through the ninth embodiments, and the semiconductor element 6 is a transistor in the tenth embodiment. However, the present disclosure is not limited to these. The type of the semiconductor element 6 is not limited and may be other semiconductor elements such as an integrated circuit. Also, three leads are disposed in the sixth through the tenth embodiments, the present disclosure is not limited to this. The number and arrangement position of leads are not limited and may be set as appropriate depending on the number and arrangement position of electrodes disposed on the element obverse surface 61 of the semiconductor element 6.
The semiconductor device according to the present disclosure is not limited to the above-described embodiments. Various modifications in design may be made freely in the specific structure of each part of the semiconductor device according to the present disclosure.
Clause 1.
A semiconductor device comprising:
a semiconductor element (6);
a first lead (1) on which the semiconductor element is mounted; and
a sealing resin (8) covering the semiconductor element and a part of the first lead,
wherein the first lead includes:
a first obverse surface (11) to which the semiconductor element is bonded;
a first reverse surface (12) facing away from the first obverse surface in a thickness direction of the first lead and exposed from the sealing resin; and
an internal reverse surface (13) facing a same side as a side that the first reverse surface faces in the thickness direction and covered with the sealing resin,
the internal reverse surface including an irregular portion (19).
Clause 2.
The semiconductor device according to clause 1, wherein
the irregular portion includes a plurality of recesses (191) recessed toward a side that the first obverse surface faces.
Clause 3. (
The semiconductor device according to clause 2, wherein,
in an extension direction orthogonal to the thickness direction and going from the first reverse surface toward an outer edge, the plurality of recesses have a larger dimension in the extension direction at a location closer to the outer edge.
Clause 4. (
The semiconductor device according to clause 3, wherein
the plurality of recesses are substantially the same in a first dimension (L3) in a direction orthogonal to the thickness direction and the extension direction.
Clause 5.
The semiconductor device according to clause 4, wherein
the first dimension is equal to or greater than 10% and equal to or less than 30% of a dimension (L4) in the extension direction of the internal reverse surface.
Clause 6.
The semiconductor device according to any one of clauses 2 to 5, wherein
the plurality of recesses are arranged in a matrix.
Clause 7. (
The semiconductor device according to any one of clauses 2 to 6, wherein
the plurality of recesses are substantially the same in a second dimension (D) in the thickness direction.
Clause 8.
The semiconductor device according to clause 7, wherein
the second dimension is equal to or greater than 1% and equal to or less than 5% of a dimension (T) from the first obverse surface to the first reverse surface in the thickness direction.
Clause 9 (Second embodiment,
The semiconductor device according to clause 1, wherein
the irregular portion includes a plurality of protrusions (192) protruding toward the side that the first reverse surface faces.
Clause 10.
The semiconductor device according to any one of clauses 1 to 9, wherein
the irregular portion is disposed over almost an entire area of the internal reverse surface.
Clause 11.
The semiconductor device according to any one of clauses 1 to 10, wherein
the first lead further includes an internal connection surface (16) connected to the first reverse surface and the internal reverse surface, and
the internal connection surface is flat and generally orthogonal to the first reverse surface and the internal reverse surface.
Clause 12.
The semiconductor device according to any one of clauses 1 to 11, wherein
an area of the semiconductor element as viewed in the thickness direction is equal to or greater than 50% of an area of the first lead as viewed in the thickness direction.
Clause 13.
The semiconductor device according to clause 1, wherein
the irregular portion includes:
a plurality of first recesses (194) extending in a first direction orthogonal to the thickness direction and arranged along a second direction orthogonal to the thickness direction and the first direction;
a plurality of first protrusions (193) located between the first recesses and extending in the first direction; and
a plurality of second protrusions (195) formed in each of the first recesses and arranged along the first direction.
Clause 14. (
The semiconductor device according to clause 13, wherein
a spacing (W2) between the plurality of second protrusions in the first direction is smaller than a spacing (W1) between the plurality of first protrusions in the second direction.
Clause 15.
The semiconductor device according to clause 13 or 14, wherein
the irregular portion includes a plurality of third protrusions (197) formed in each of the first protrusions and arranged along the first direction.
Clause 16. (
The semiconductor device according to clause 15, wherein
a spacing (W3) between the plurality of third protrusions in the first direction is smaller than the spacing between the plurality of first protrusions in the second direction.
Clause 17. (
The semiconductor device according to any one of clauses 13 to 16, wherein
the irregular portion further includes a plurality of second recesses (196) located between the second protrusions and arranged along the first direction, and
a second height difference (T3) between the second protrusions and the second recesses in the thickness direction is smaller than a first height difference (T1) between the first protrusions and the first recesses in the thickness
Clause 18.
The semiconductor device according to clause 17, wherein
the second height difference is equal to or less than 25% of the first height difference.
Clause 19.
The semiconductor device according to clause 17 or 18, wherein
the first height difference is equal to or greater than 1% and equal to or less than 5% of a dimension (T2) from the first obverse surface to the internal reverse surface in the thickness direction.
Clause 20.
The semiconductor device according to any one of clauses 13 to 19, wherein
the irregular portion is disposed at least on an outer edge of the first internal reverse surface.
Clause 21.
The semiconductor device according to any one of clauses 13 to 20, wherein
the first direction is a direction away from the first reverse surface.
Clause 22.
The semiconductor device according to any one of clauses 13 to 21, further comprising
an internal connection surface (16) generally orthogonal to the first reverse surface and the internal reverse surface and connected to the first reverse surface and the internal reverse surface.
Clause 23.
The semiconductor device according to any one of clauses 13 to 22, wherein
an area of the semiconductor element as viewed in the thickness direction is equal to or greater than 70% of an area of the first lead as viewed in the thickness direction.
Clause 24. (
A method for manufacturing a semiconductor device, comprising the steps of:
preparing (S11) a metal plate including an obverse surface and a reverse surface that face away from each other in a thickness direction;
forming (S12, S13) a first lead (1) by subjecting the metal plate to a stamping process, the first lead including an internal reverse surface (13) facing a same side as a side that the reverse surface faces and located closer to the obverse surface than is the reverse surface in the thickness direction (S12, S13);
bonding (S20) a semiconductor element (6) to the first lead; and
forming (S40) a sealing resin (8) that covers the semiconductor element,
wherein
the step of forming the first lead includes using a die (95) including an irregularity-forming part (951) and pressing the irregularity-forming part against the metal plate from the reverse surface side to form the internal reverse surface including an irregular portion (19).
Clause 25. (First embodiment,
The method for manufacturing a semiconductor device according to clause 24, wherein
the irregularity-forming part includes a plurality of protrusions (952).
Clause 26, Second embodiment,
The method for manufacturing a semiconductor device according to clause 24, wherein
the irregularity-forming part includes a plurality of recesses (953).
Clause 27. (
A method for manufacturing a semiconductor device, comprising the steps of:
preparing (S11) a metal plate including an obverse surface and a reverse surface that face away from each other in a thickness direction;
forming (S15) a lead frame (91) by working the metal plate, the lead frame including an internal reverse surface (13) facing a same side as a side that the reverse surface faces and located closer to the obverse surface than is the reverse surface in the thickness direction;
forming (S16) an irregular portion (19) on the internal reverse surface by laser irradiation;
bonding (S20) a semiconductor element (6) to the lead frame,
forming (S40) a sealing resin (8) that covers the semiconductor element; and cutting (S50) the lead frame.
Clause 28.
The method for manufacturing a semiconductor device according to clause 27, wherein
the step of forming the irregular portion includes:
emitting the laser as a pulsed output;
scanning the laser in the first direction to form a first recess (194) extending in the first direction; and
forming a plurality of the first recesses while moving a laser irradiation position in a second direction orthogonal to the thickness direction and the first direction to form first protrusions (193) between the first recesses,
wherein, in each of the first recesses, a plurality of second protrusions (195) are formed that are arranged along the first direction at intervals corresponding to a frequency of the pulsed output.
Clause 29.
The method for manufacturing a semiconductor device according to clause 27 or 28, wherein
the irregular portion is formed at least on an outer edge of the internal reverse surface.
Clause 30.
The method for manufacturing a semiconductor device according to any one of clauses 27 to 29, wherein
the step of forming the lead frame includes forming the lead frame by subjecting the metal plate to a stamping process.
Number | Date | Country | Kind |
---|---|---|---|
2021-115672 | Jul 2021 | JP | national |
2021-119864 | Jul 2021 | JP | national |
Number | Date | Country | |
---|---|---|---|
Parent | PCT/JP2022/027186 | Jul 2022 | US |
Child | 18528149 | US |