JP7385690B2 - semiconductor equipment - Google Patents

Description

The present invention relates to a semiconductor device.

Various configurations have been proposed for semiconductor devices including semiconductor elements such as transistors. Patent Document 1 discloses an example of a conventional semiconductor device. The semiconductor device disclosed in this document includes a semiconductor element, a plurality of leads, and a sealing resin. The semiconductor element is supported by one of the plurality of leads and is electrically connected to the plurality of leads. The sealing resin covers each of the plurality of leads and the semiconductor element. The portions of the plurality of leads exposed from the sealing resin constitute a plurality of mounting parts used when mounted on a circuit board or the like. The plurality of mounting parts are joined to the circuit board by, for example, solder.

Depending on the specifications and usage environment of the semiconductor device, stress is generated in the solder that joins the multiple mounting parts and the circuit board. It is undesirable for this stress to cause cracks in the solder or for the solder to peel off.

JP2009-71033A

The present invention was conceived under the above-mentioned circumstances, and an object of the present invention is to provide a semiconductor device that can increase mounting strength.

A semiconductor device provided by the present invention has a semiconductor element, a main surface and a back surface facing opposite to each other in the thickness direction, supports the semiconductor element by one of the main surfaces, and supports the semiconductor element. A semiconductor device comprising a plurality of leads that are electrically connected to each other, and a sealing resin that covers each of the plurality of leads and the semiconductor element, wherein each of the plurality of leads has a back surface that is connected to the sealing resin. an outer portion that is exposed from the outside, is arranged on one end side in a first direction perpendicular to the thickness direction, and is located at the outermost side in the thickness direction and a second direction perpendicular to the first direction; and an inner back mounting portion located inward of the outer back mounting portion in the second direction, and the area of the outer back mounting portion is larger than the inner back mounting portion. It is characterized by being larger than the area of the mounting part.

In a preferred embodiment of the present invention, the area ratio of the outer back mounting portion to the area of the inner back mounting portion is 1.7 to 2.5.

In a preferred embodiment of the present invention, when the dimension in the second direction of the inner back mounting portion is 1, a dimension ratio of the outer back mounting portion is 1.7 to 2.5.

In a preferred embodiment of the present invention, the ratio of the dimension ratios when the area ratio is 1 is 0.68 to 1.47.

In a preferred embodiment of the present invention, the plurality of leads have a pair of outer back mounting portions located on both sides in the second direction.

In a preferred embodiment of the present invention, the plurality of leads include a first lead and a second lead each having the outer back surface mounting portion.

In a preferred embodiment of the present invention, the second lead includes the inner back surface mounting portion.

In a preferred embodiment of the present invention, the first lead has a first tip surface facing outward in the first direction when viewed in the thickness direction, and a first tip surface facing inward in the first direction from the first tip surface. It has a recessed first concave end surface.

In a preferred embodiment of the present invention, the first lead has a first terminal portion having the first tip surface and the first concave end surface, and the back surface belongs to the first terminal portion. portion constitutes the outer back surface mounting portion.

In a preferred embodiment of the present invention, the outer back mounting portion has a first tip edge that is a boundary edge with the first tip surface, and a second tip edge that is a boundary edge with the first concave end surface. and a concave edge.

In a preferred embodiment of the present invention, a first main surface plating layer provided on the main surface of the first lead, a first back plating layer provided on the back surface of the first lead, and a first lead plating layer provided on the back surface of the first lead. a first side plating layer that covers the first concave end surface and exposes the first end surface.

In a preferred embodiment of the present invention, the first back surface plating layer and the first side surface plating layer are made of the same material and are connected to each other.

In a preferred embodiment of the present invention, the first main surface plating layer, the first back surface plating layer, and the first side surface plating layer are made of different materials.

In a preferred embodiment of the present invention, the first lead includes a first wire bonding portion located on a side facing the main surface in the thickness direction with respect to the first terminal portion; and a first bent part connecting the first terminal part and the first terminal part.

In a preferred embodiment of the present invention, the first lead has a first through hole that penetrates in the thickness direction and overlaps the first bent portion when viewed in the thickness direction.

In a preferred embodiment of the present invention, the first through hole overlaps the first terminal portion and the first wire bonding portion when viewed in the thickness direction.

In a preferred embodiment of the present invention, the first lead has a first concave end side surface that is concave from the outside to the inside in the second direction when viewed in the thickness direction.

In a preferred embodiment of the present invention, the first concave end side surface overlaps the first bent portion and the first wire bonding portion when viewed in the thickness direction.

In a preferred embodiment of the present invention, the second lead has a second tip surface facing outward in the first direction when viewed in the thickness direction, and a second tip surface facing inward in the first direction from the second tip surface. and a second concave end surface.

In a preferred embodiment of the present invention, the second lead has a second outer terminal portion having the second tip end surface and the second concave end surface, and the second outer terminal portion includes the second outer terminal portion of the back surface. The portion belonging to the terminal portion constitutes the outer back surface mounting portion.

In a preferred embodiment of the present invention, the outer back mounting portion has a second tip edge that is a boundary edge with the second tip surface and a second tip edge that is a boundary edge with the second concave end surface. and a concave edge.

In a preferred embodiment of the present invention, a second main surface plating layer provided on the main surface of the second lead, a second back plating layer provided on the back surface of the second lead, and a second main surface plating layer provided on the back surface of the second lead. a second side plating layer that covers the second concave end surface and exposes the second tip end surface.

In a preferred embodiment of the present invention, the second back surface plating layer and the second side surface plating layer are made of the same material and are connected to each other.

In a preferred embodiment of the present invention, the second main surface plating layer, the second back surface plating layer, and the second side surface plating layer are made of different materials.

In a preferred embodiment of the present invention, the second lead includes a second wire bonding portion located on a side facing the back surface in the thickness direction with respect to the second outer terminal portion; It has a second bent part that connects the bonding part and the second outer terminal part.

In a preferred embodiment of the present invention, the second lead has a second through hole that penetrates in the thickness direction and overlaps with the second bent portion when viewed in the thickness direction.

In a preferred embodiment of the present invention, the second through hole overlaps the second outer terminal portion and the second wire bonding portion when viewed in the thickness direction.

In a preferred embodiment of the present invention, the second lead has a second concave end side surface that is concave from the outside to the inside in the second direction when viewed in the thickness direction.

In a preferred embodiment of the present invention, the second concave end side surface overlaps the second bent portion and the second wire bonding portion when viewed in the thickness direction.

In a preferred embodiment of the present invention, the second lead has a second inner terminal portion located inward in the second direction with respect to the second outer terminal portion, and Of these, the portion belonging to the second inner terminal portion constitutes the inner back surface mounting portion.

In a preferred embodiment of the present invention, the plurality of leads are spaced apart from each other in the first direction with respect to the first lead and the second lead, and have an element bonding portion on which the semiconductor element is mounted. 3 leads, and the third lead has an element-side back surface mounting portion consisting of a portion of the back surface exposed from the sealing resin.

In a preferred embodiment of the present invention, the third lead has a plurality of terminal-like extensions each extending from the element bonding portion in the first direction and arranged in the second direction.

In a preferred embodiment of the present invention, the third lead has a lateral extending portion extending from the element bonding portion in the second direction.

In a preferred embodiment of the present invention, the third lead has a backside recess that is recessed in the thickness direction from the backside at the end when viewed in the thickness direction.

In a preferred embodiment of the present invention, the third lead has an eaves portion that connects to the main surface side in the thickness direction with respect to the back side recess and projects outward when viewed in the thickness direction. .

In a preferred embodiment of the present invention, the third lead is interposed between the main surface and the eave part and located inwardly than the eave part when viewed in the thickness direction. It has an end surface.

In a preferred embodiment of the present invention, the intermediate end surface on the main surface side overlaps with the recess on the back surface side when viewed in the thickness direction.

In a preferred embodiment of the present invention, the third lead has a main surface side recess that is provided at a position away from the semiconductor element when viewed in the thickness direction and that is recessed from the main surface in the thickness direction.

In a preferred embodiment of the present invention, the semiconductor element includes an element body, a first electrode and a second electrode provided on a side facing the main surface of the element body, and a first electrode and a second electrode provided on a side facing the main surface of the element body; and a third electrode provided on the side.

In a preferred embodiment of the present invention, a first wire connected to the first electrode and the first wire bonding part of the first lead, and a first wire connected to the second electrode and the second wire bonding part of the second lead. a second wire connected to the bonding portion.

In a preferred embodiment of the present invention, the third electrode is bonded to the element bonding portion of the third lead using a conductive bonding material.

In a preferred embodiment of the present invention, the first electrode is a gate electrode, the second electrode is a source electrode, and the third electrode is a drain electrode.

According to the present invention, the outer back surface mounting section is located at the outermost position in the second direction. The area of the outer back mounting portion is larger than the inner back mounting portion located inward in the second direction. According to the inventors' research, when a durability test was conducted in which the semiconductor device mounted on a circuit board or the like by solder was exposed alternately to a low temperature state and a high temperature state, the solder located at the outermost position in the second direction had a larger It was found that stress occurs. According to the semiconductor device, since the area of the outer back mounting portion located at the outermost side is relatively large, it is possible to suppress the occurrence of cracks or the like due to stress. Therefore, the mounting strength of the semiconductor device can be increased.

Other features and advantages of the invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

FIG. 1 is a plan view showing a semiconductor device according to a first embodiment of the present invention. FIG. 1 is a bottom view showing a semiconductor device according to a first embodiment of the present invention. FIG. 1 is a plan view of essential parts of a semiconductor device according to a first embodiment of the present invention. FIG. 1 is an enlarged plan view of a main part of a semiconductor device according to a first embodiment of the present invention. FIG. 1 is an enlarged plan view of a main part of a semiconductor device according to a first embodiment of the present invention. 4 is a cross-sectional view taken along line VI-VI in FIG. 3. FIG. FIG. 4 is an enlarged cross-sectional view of a main part taken along line VI-VI in FIG. 3; 4 is a cross-sectional view taken along line VIII-VIII in FIG. 3. FIG. FIG. 4 is an enlarged cross-sectional view of a main part taken along line VIII-VIII in FIG. 3; 4 is a sectional view taken along line XX in FIG. 3. FIG. FIG. 4 is an enlarged sectional view of a main part taken along the line XX in FIG. 3; FIG. 4 is an enlarged sectional view of a main part taken along the line XII-XII in FIG. 3. FIG. 4 is a sectional view taken along line XIII-XIII in FIG. 3. FIG. 1 is a plan view of a main part showing one step in manufacturing a semiconductor device according to a first embodiment of the present invention. FIG. 1 is a plan view of a main part showing one step in manufacturing a semiconductor device according to a first embodiment of the present invention. FIG. 5 is a graph showing crack growth test results for a semiconductor device based on the first embodiment of the present invention and a semiconductor device of a comparative example. FIG. 7 is an enlarged plan view of a main part showing a modification of the semiconductor device based on the first embodiment of the present invention. FIG. 7 is an enlarged plan view of main parts showing another modification of the semiconductor device based on the first embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

1 to 13 show a semiconductor device based on a first embodiment of the present invention. The semiconductor device A1 of this embodiment includes a plurality of leads 1, 2, 3, a semiconductor element 4, and a sealing resin 6.

FIG. 1 is a plan view showing the semiconductor device A1. FIG. 2 is a bottom view showing the semiconductor device A1. FIG. 3 is a plan view of essential parts of the semiconductor device A1. FIG. 4 is an enlarged plan view of the main parts of the semiconductor device A1. FIG. 5 is an enlarged plan view of essential parts of the semiconductor device A1. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. FIG. 7 is an enlarged sectional view of a main part taken along line VI-VI in FIG. 3. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 3. FIG. 9 is an enlarged sectional view of a main part taken along line VIII-VIII in FIG. FIG. 10 is a sectional view taken along line XX in FIG. 3. FIG. 11 is an enlarged sectional view of a main part taken along line XX in FIG. 3. FIG. 12 is an enlarged sectional view of a main part taken along line XII-XII in FIG. 3. FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. The y direction is the first direction of the invention, the x direction is the second direction of the invention, and the z direction is the thickness direction of the invention.

The size of the semiconductor device A1 is not particularly limited, and in this embodiment, for example, the dimension in the x direction is 2.6 to 3.6 mm, the dimension in the y direction is 2.6 mm to 3.6 mm, and the dimension in the z direction is 0.7 mm. ~1.0mm.

The plurality of leads 1, 2, and 3 support the semiconductor element 4 and are electrically connected to the semiconductor element 4. In the following description, they will be referred to as a first lead 1, a second lead 2, and a third lead 3. The first lead 1, second lead 2, and third lead 3 are formed, for example, by punching or bending a metal plate. The first lead 1, the second lead 2, and the third lead 3 are made of metal, preferably Cu or Ni, or an alloy thereof, a 42 alloy, or the like. The thickness of the first lead 1, second lead 2, and third lead 3 is, for example, 0.1 mm to 0.3 mm, and in this embodiment is about 0.2 mm.

As shown in FIG. 3, the first lead 1 and the second lead 2 are arranged in the x direction. The third lead 3 is spaced apart from the first lead 1 and the second lead 2 in the y direction. The third lead 3 has the largest dimension in the z direction, and the first lead 1 has the smallest dimension.

As shown in FIGS. 6 and 7, the first lead 1 has a main surface 101 and a back surface 102. As shown in FIG. The main surface 101 and the back surface 102 face opposite to each other in the z direction. As shown in FIGS. 4, 6, and 7, the first lead 1 has a first wire bonding part 111, a first terminal part 112, and a first bent part 115. The first wire bonding part 111 is located on the side where the main surface 101 faces in the z direction with respect to the first terminal part 112. Further, the first wire bonding section 111 is located inward in the y direction with respect to the first terminal section 112. In this embodiment, the difference in z-direction position between the first wire bonding part 111 and the first terminal part 112 is about 0.15 mm. The first bent portion 115 connects the first wire bonding portion 111 and the first terminal portion 112, and has a bent shape when viewed in the x direction.

The first terminal portion 112 has two first end surfaces 121 and one first concave end surface 122. The first tip surface 121 is a surface facing outward in the y direction. The first concave end surface 122 is a surface that is recessed inward in the y direction when viewed in the z direction with respect to the first tip surface 121 . The first concave end surface 122 is sandwiched between the two first end surfaces 121 in the x direction.

As shown in FIG. 2, a portion of the back surface 102 that belongs to the first terminal section 112 constitutes an outer back mounting section 150. As shown in FIG. 7, the outer back mounting portion 150 is exposed from the sealing resin 6 and is a portion that is bonded with solder 92 when the semiconductor device A1 is mounted on the circuit board 91. The outer back mounting portion 150 has a tip edge 151 that is a boundary edge with the first tip surface 121 and a concave edge 152 that is a boundary edge with the first concave end surface 122 .

As shown in FIGS. 4, 6, and 7, the first lead 1 has a first concave side surface 123 and a first through hole 130. The first concave end side surface 123 is concave inward from the outside in the x direction when viewed in the z direction. The first concave end side surface 123 overlaps with the first wire bonding portion 111 and the first bent portion 115 when viewed in the z direction. The first through hole 130 penetrates the first lead 1 in the z direction. The first through hole 130 overlaps with the first bent portion 115 when viewed in the z direction. Further, the first through hole 130 overlaps with the first wire bonding part 111 and the first terminal part 112 when viewed in the z direction.

A portion of the main surface 101 is covered with a first main surface plating layer 191. The first main surface plating layer 191 is made of, for example, an Ag plating layer. In this embodiment, portions of the main surface 101 that belong to the first wire bonding section 111 and the first bent section 115 are covered with the first main surface plating layer 191.

The back surface 102 is covered with a first back plating layer 192. The first concave end surface 122 is covered with a first side plating layer 193. Further, the first side plating layer 193 exposes the two first end surfaces 121. The first back surface plating layer 192 and the first side surface plating layer 193 are made of the same material and are connected to each other. The first main surface plating layer 191, the first back surface plating layer 192, and the first side surface plating layer 193 are made of different materials. The first back surface plating layer 192 and the first side surface plating layer 193 are made of, for example, a Sn plating layer.

As shown in FIGS. 8, 9, and 12, the second lead 2 has a main surface 201 and a back surface 202. The main surface 201 and the back surface 202 face opposite to each other in the z direction. As shown in FIGS. 5, 8, 9, and 12, the second lead 2 includes a second wire bonding part 211, a second outer terminal part 212, two second inner terminal parts 213, and a third It has two bent parts 215. The second wire bonding part 211 is located on the side where the main surface 201 faces in the z direction with respect to the second outer terminal part 212 and the two second inner terminal parts 213. Further, the second wire bonding section 211 is located inward in the y direction with respect to the second outer terminal section 212 and the two second inner terminal sections 213. In this embodiment, the difference in z-direction position between the second wire bonding part 211, the second outer terminal part 212, and the two second inner terminal parts 213 is about 0.15 mm. The three second bent portions 215 individually connect the second wire bonding portion 211, the second outer terminal portion 212, and the two second inner terminal portions 213, and have a bent shape when viewed in the x direction. The second outer terminal portion 212 is located at the outermost position in the x direction. The two second inner terminal portions 213 are located inward in the x direction with respect to the second outer terminal portion 212 and are lined up in the x direction. Further, the two second inner terminal portions 213 are sandwiched between the first terminal portion 112 and the second outer terminal portion 212 in the x direction.

The second outer terminal portion 212 has two second end surfaces 221 and one second concave end surface 222 . The second tip surface 221 is a surface facing outward in the y direction. The second concave end surface 222 is a surface that is recessed inward in the y direction when viewed in the z direction with respect to the second tip surface 221 . The second concave end surface 222 is sandwiched between the two second end surfaces 221 in the x direction.

As shown in FIG. 2, a portion of the back surface 102 that belongs to the second outer terminal section 212 constitutes an outer back mounting section 250. The outer back mounting portion 250 is exposed from the sealing resin 6, and is a portion that is bonded with solder 92 when the semiconductor device A1 is mounted on the circuit board 91, as shown in FIG. The outer back mounting portion 250 has a second tip edge 251 that is a boundary edge with the second tip surface 221 and a second concave edge 252 that is a boundary edge with the second concave end surface 222 .

As shown in FIG. 2, portions of the back surface 102 that belong to the two second inner terminal sections 213 constitute two inner back surface mounting sections 260. The inner back mounting portion 260 is exposed from the sealing resin 6 and is a portion that is bonded with solder 92 when the semiconductor device A1 is mounted on the circuit board 91.

As shown in FIGS. 5, 8, 9, and 12, the second lead 2 has a second concave side surface 223 and a second through hole 230. The second concave end side surface 223 is concave inward from the outside in the x direction when viewed in the z direction. The second concave end side surface 223 overlaps with the second wire bonding part 211 and the second bent part 215 when viewed in the z direction. The second through hole 230 penetrates the second lead 2 in the z direction. The second through hole 230 overlaps with the second bent portion 215 when viewed in the z direction. Moreover, the second through hole 230 overlaps with the second wire bonding part 211 and the second outer terminal part 212 when viewed in the z direction.

As shown in FIG. 3, a portion of the main surface 201 is covered with a second main surface plating layer 291. The second main surface plating layer 291 is made of, for example, an Ag plating layer. In this embodiment, portions of the main surface 201 that belong to the second wire bonding section 211 and the second bending section 215 are covered with the second main surface plating layer 291.

As shown in FIGS. 8, 9, and 12, the back surface 202 is covered with a second back plating layer 292. The second concave end surface 222 is covered with a second side plating layer 293. Further, the second side plating layer 293 exposes the two second end surfaces 221. Further, the second side surface plating layer 293 exposes the end surface of the inner back surface mounting section 260. The second back surface plating layer 292 and the second side surface plating layer 293 are made of the same material and are connected to each other. The second main surface plating layer 291, the second back surface plating layer 292, and the second side surface plating layer 293 are made of different materials. The second back surface plating layer 292 and the second side surface plating layer 293 are made of, for example, a Sn plating layer.

As shown in FIG. 2, the outer back mounting portion 150 and the outer back mounting portion 250 are arranged at the outermost position on both sides in the x direction, and the two inner back mounting portions 260 are arranged in the outer back mounting portion. 150 and the outer back mounting section 250.

Examples of dimensions and areas of the outer back mounting section 150, the outer back mounting section 250, and the inner back mounting section 260 are listed below.

The dimension L1 in the x direction of the outer back mounting section 150 and the outer back mounting section 250 shown in FIG. 2 is about 0.7 mm, and the dimension L2 in the x direction of the inner back mounting section 260 is about 0.3 mm. The distance between the outer back surface mounting portion 150 and the inner back surface mounting portion 260 is the same as the distance between 250 and 260, and this dimension S1 is 0.27 mm. Further, the dimension S2, which is the interval between the two inner back surface mounting parts 260, is 0.27 mm, which is equal to the dimension S1. The dimension ratio R2 of the dimension L2 when the dimension L2 is 1 is 2.33. This size ratio R2 is preferably 1.7 to 2.5. In this embodiment, the outer back mounting section 150, the outer back mounting section 250, and the two inner back mounting sections 260 all have the same dimension in the y direction. The outer back mounting portion 150 and the outer back mounting portion 250 have an elongated rectangular shape with the x direction as the longitudinal direction. The 2t inner back mounting section 260 has a rectangular shape that is less flat than the outer back mounting section 150 and the outer back mounting section 250.

The areas of the outer back mounting portion 150 and the outer back mounting portion 250 are equal, and their area E1 is 0.222 mm 2 . The area E2 of the two inner back surface mounting parts 260 is 0.096 mm2. The area ratio R1 of the area E1 when the area E2 is 1 is 2.31. This area ratio R1 is preferably 1.7 to 2.5.

When the area ratio R1 is 1, the ratio R3 of the dimension ratio R2 is 1.01. This ratio R3 is preferably 0.68 to 1.47.

As shown in FIGS. 10 and 11, the third lead 3 has a main surface 301 and a back surface 302. As shown in FIG. 3, the main surface 301 and the back surface 302 face oppositely to each other in the z direction. The third lead 3 has an element bonding portion 311, a plurality of terminal-like extensions 312, and two lateral extensions 313. The element bonding part 311 has, for example, a rectangular shape when viewed in the z direction, and the semiconductor element 4 is mounted thereon. Each of the plurality of terminal-shaped extension parts 312 extends in the y direction from the element bonding part 311 and is arranged in the x direction. The two lateral extensions 313 extend from the element bonding section 311 on both sides in the x direction.

As shown in FIG. 2, a portion of the back surface 302 exposed from the sealing resin 6 constitutes an element-side back mounting section 350. In this embodiment, the entire back surface 302 constitutes an element-side back surface mounting section 350. The element side back surface mounting portion 350 is a portion that is bonded with solder 92 when the semiconductor device A1 is mounted on the circuit board 91.

As shown in FIGS. 10 and 11, the third lead 3 has a recess 361 on the back surface side, an eaves section 362, and an intermediate end surface 363 on the main surface side.

The backside recess 361 is recessed in the z-direction from the backside 302 at the end of the third lead 3 when viewed in the z-direction. The eaves portion 362 is connected to the main surface 301 side in the z direction with respect to the back side recessed portion 361, and protrudes outward when viewed in the z direction. The main surface side intermediate end surface 363 is interposed between the main surface 301 and the eaves section 362 and is located inward from the eaves section 362 when viewed in the z direction. The main surface side intermediate end surface 363 overlaps with the back surface side recessed portion 361 when viewed in the thickness direction.

In this embodiment, the back surface side recess 361, the eaves section 362, and the main surface side intermediate end surface 363 are located at the edges of the third lead 3 on the first lead 1 and second lead 2 sides when viewed in the z direction, and on both sides in the x direction. It is provided at the end edge and the end edge on the opposite side from the first lead 1 and the second lead 2 in the y direction and between the plurality of terminal-like extensions 312 .

As shown in FIG. 3, the third lead 3 has a plurality of main surface side recesses 371. As shown in FIG. The main surface side recess 371 is provided at a position away from the semiconductor element 4 when viewed in the z direction, and is recessed from the main surface 301 in the thickness direction. In this embodiment, the plurality of main surface side recesses 371 are provided at the root portions of the plurality of terminal-like extensions 312 and the two lateral extensions 313.

As shown in FIG. 11, the main surface 301 of the third lead 3 is covered with a third main surface plating layer 391. In the illustrated example, a third main surface plating layer 391 is provided on a portion of the main surface 301 excluding the portions belonging to the plurality of terminal-like extensions 312 . The third main surface plating layer 391 is made of, for example, an Ag plating layer.

The back surface 302 is covered with a third back surface plating layer 392. A portion of the side surface of the third lead 3 excluding the tip surfaces of the plurality of terminal-like extensions 312 and the tip surfaces of the two side extensions 313 is covered with a third side surface plating layer 393 . The third back surface plating layer 392 and the third side surface plating layer 393 are made of the same material and are connected to each other. The third main surface plating layer 391, the third back surface plating layer 392, and the third side surface plating layer 393 are made of different materials. The third back surface plating layer 392 and the third side surface plating layer 393 are made of, for example, a Sn plating layer.

The semiconductor element 4 is an element that performs the electrical functions of the semiconductor device A1. The type of semiconductor element 4 is not particularly limited, and as shown in FIGS. 3 and 6, in this embodiment, the semiconductor element 4 is configured as a transistor. The semiconductor element 4 includes an element body 40, a first electrode 41, a second electrode 42, and a third electrode 43.

The first electrode 41 and the second electrode 42 are provided on a surface of the element body 40 facing the same side as the main surface 301. The third electrode 43 is provided on the surface of the element body 40 facing the same side as the back surface 302. In this embodiment, the first electrode 41 is a gate electrode, the second electrode 42 is a source electrode, and the third electrode 43 is a drain electrode.

The semiconductor device A1 has a first wire 51 and a plurality of second wires 52. The first wire 51 is connected to the first electrode 41 and the first wire bonding portion 111 of the first lead 1 . The plurality of second wires 52 are connected to the second electrode 42 and the second wire bonding portion 211 of the second lead 2.

The third electrode 43 is mounted on the element bonding portion 311 of the third lead 3 via a conductive bonding material 49. More specifically, the conductive bonding material 49 bonds the third electrode 43 and the third principal surface plating layer 391 provided on the principal surface 301 of the element bonding portion 311.

The sealing resin 6 covers parts of each of the first lead 1 , the second lead 2 , and the third lead 3 , the semiconductor element 4 , the first wire 51 , and the plurality of second wires 52 . The sealing resin 6 is made of, for example, black epoxy resin.

As shown in FIGS. 1, 2, and 6, the sealing resin 6 has a sealing resin main surface 61, a sealing resin back surface 62, and a sealing resin side surface 63. The sealing resin main surface 61 and the sealing resin back surface 62 face opposite sides in the z direction. The sealing resin main surface 61 faces the same side as the main surface 101, the main surface 201, and the main surface 301. The sealing resin back surface 62 faces the same side as the back surface 102, the back surface 202, and the back surface 302. The sealing resin side surface 63 is connected to the sealing resin main surface 61 and the sealing resin back surface 62, and is slightly inclined with respect to the z direction.

The outer back mounting portion 150, the outer back mounting portion 250, the two inner back mounting portions 260, and the element side back mounting portion 350 are all exposed from the sealing resin 6. Further, the outer back mounting portion 150, the outer back mounting portion 250, the two inner back mounting portions 260, and the element side back mounting portion 350 are flush with the sealing resin back surface 62 of the sealing resin 6.

FIG. 14 shows a lead frame 10 used in manufacturing the semiconductor device A1. The lead frame 10 is a metal plate material having portions that will become the first lead 1, second lead 2, and third lead 3 described above.

A first main surface plating layer 191 , a second main surface plating layer 291 , and a third main surface plating layer 391 are formed in predetermined areas of the lead frame 10 at the parts that are to become the main surface 101 , the main surface 201 , and the main surface 301 . An Ag plating layer is provided. Sn plating layers, which will become the first back plating layer 192, the second back plating layer 292, and the third back plating layer 392, are provided on the entire surface of the parts of the lead frame 10 that are to become the back surface 102, the back surface 202, and the back surface 302. ing. Sn plating layers, which become a first side plating layer 193, a second side plating layer 293, and a third side plating layer 393, are provided on the side surfaces of the lead frame 10 along the z direction.

As shown in FIG. 15, the semiconductor element 4 is mounted on the lead frame 10. Next, the first wire 51 and the plurality of second wires 52 are bonded. Next, a sealing resin 6 is formed. Then, the lead frame 10 is cut along the cutting lines 81, 82, and 83. The first tip surface 121 of the first terminal portion 112, the second tip surface 221 of the second outer terminal portion 212, the tip surface of the terminal-like extension portion 312, and the tip of the side extension portion 313 are formed by this cutting. The surface is a cut surface of the lead frame 10, and is a surface on which the first side plating layer 193, the second side plating layer 293, and the third side plating layer 393 are not provided.

Next, the operation of the semiconductor device A1 will be explained.

According to this embodiment, the outer back mounting section 150 and the outer back mounting section 250 are located at the outermost position in the x direction. The areas of the outer back mounting section 150 and the outer back mounting section 250 are larger than the inner back mounting section 260 located inward in the x direction. According to research conducted by the inventors, when a durability test was conducted in which a semiconductor device A1 mounted on a circuit board 91 or the like with solder 92 was exposed alternately to a low temperature state and a high temperature state, the solder 92 located at the outermost position in the x direction It was found that large stresses were generated. According to the semiconductor device A1, since the areas of the outer back mounting section 150 and the outer back mounting section 250 located at the outermost side are relatively large, it is possible to suppress the occurrence of cracks and the like due to stress. It is possible. Therefore, the mounting strength of the semiconductor device A1 can be increased.

In the semiconductor device A1, an outer back mounting section 150 and an outer back mounting section 250 are provided on both sides in the x direction. This makes it possible to suppress the occurrence of cracks in the solder 92 on both sides in the x direction in a well-balanced manner.

FIG. 16 shows the results of a crack growth test between the semiconductor device A1 and a semiconductor device as a comparative example. In this test, a semiconductor device mounted on a circuit board etc. with solder is subjected to multiple cycles of temperature changes, with one cycle being set to a low temperature state (-55 degrees) and a high temperature state (150 degrees). Second, the degree of growth of cracks occurring in the solder was measured. The horizontal axis is the number of temperature cycles performed, and the vertical axis is the crack growth rate when the state where the solder completely peels off is taken as 100%. In the comparative example, all the back surface mounting sections have the same configuration as the inner back surface mounting section 260, and there is no difference in size. That is, this corresponds to an example in which the area ratio R1 is 1.0. As shown in the figure, in the comparative example, the crack growth rate was 53% after 1000 cycles, and reached 100% after 1765 cycles. On the other hand, in the outer back mounting section 150 and the outer back mounting section 250 of the semiconductor device A1, the crack growth rate was 18% after 1000 cycles and 59% after 2000 cycles. The crack growth rate reached 100% after 3900 cycles. In this way, the semiconductor device A1 can clearly suppress the growth of solder cracks compared to the comparative example. The lower limit of the number of cycles at which the crack growth rate reaches 100% is preferably 3000 cycles, and in this case, the area ratio R1 was 1.7. Furthermore, when the area ratio R1 and the dimension ratio R2 exceed 2.5, the exclusive area of the outer back mounting section 150 and the outer back mounting section 250 in the semiconductor device A1 becomes excessive, and the layout of the back mounting section becomes distorted. It becomes.

From the above, when the area of the inner back mounting section 260 is 1, the area ratio R1 of the areas of the outer back mounting section 150 and the outer back mounting section 250 is 1.7 to 2.5. This is preferable to prevent the semiconductor device A1 from increasing in size due to the outer back mounting portion 150 and the outer back mounting portion 250 becoming extremely large, while suppressing the occurrence of cracks in the solder 92.

When the x-direction dimension of the inner back-mounted part 260 is 1, the dimension ratio R2 of the x-direction dimensions of the outer back-mounted part 150 and the outer back-mounted part 250 is 1.7 to 2.5. , it is possible to suppress the outer back surface mounting portion 150 and the outer back surface mounting portion 250 from becoming extremely large in the y direction while keeping the area ratio R1 within the above range. In this embodiment, the dimensions in the y direction of the outer back mounting section 150 and the outer back mounting section 250 and the inner back mounting section 260 are the same, and the outer back mounting section 150 and the outer back mounting section 250 are , is not configured to protrude in the y direction with respect to the inner back surface mounting portion 260.

In order to realize the above-mentioned area ratio R1 and size ratio R2, it is preferable that the ratio R3 of the size ratio R2 is 0.68 to 1.47 when the area ratio R1 is 1.

As shown in FIGS. 4 and 7, the first terminal portion 112 is provided with two first end surfaces 121 and a first concave end surface 122. Since the first tip surface 121 is constituted by a surface cut in the step shown in FIG. 15, the first lead 1 is exposed. On the other hand, the first concave end surface 122 is covered with a first side plating layer 193. The first side plating layer 193 is made of, for example, a Sn plating layer, and has better wettability to the solder 92 than the first lead 1 . Therefore, when the outer back mounting portion 150 is bonded to the circuit board 91 with the solder 92, the solder 92 also covers the first side plating layer 193 (first concave end surface 122). This allows the mounting strength to be further increased. Further, the first side plating layer 193 is formed of the same plating layer that is connected to the first back plating layer 192. As a result, the solder 92 is integrally attached to the outer back surface mounting portion 150 (first back surface plating layer 192) and the first concave end surface 122 (first side surface plating layer 193). This is suitable for improving mounting strength.

As shown in FIGS. 5 and 9, the second outer terminal portion 212 is provided with two second tip surfaces 221 and a second concave end surface 222. As shown in FIGS. Since the second tip surface 221 is constituted by a surface cut in the step shown in FIG. 15, the second lead 2 is exposed. On the other hand, the second concave end surface 222 is covered with a second side plating layer 293. The second side plating layer 293 is made of, for example, a Sn plating layer, and has better wettability to the solder 92 than the second lead 2. Therefore, when the outer back mounting portion 250 is bonded to the circuit board 91 with the solder 92, the solder 92 also covers the second side plating layer 293 (second concave end surface 222). This allows the mounting strength to be further increased. Further, the second side plating layer 293 is formed of the same plating layer that is connected to the second back side plating layer 292. As a result, the solder 92 is integrally attached to the outer back surface mounting portion 250 (second back surface plating layer 292) and the second concave end surface 222 (second side surface plating layer 293). This is suitable for improving mounting strength.

A larger current flows through the second electrode 42 which is the source electrode than the first electrode 41 which is the gate electrode. Providing the second outer terminal portion 212 and the two second inner terminal portions 213 on the second lead 2 through which this large current flows is preferable for lowering the resistance.

By providing the first concave side surface 123 and the first through hole 130, the bonding strength between the first lead 1 and the sealing resin 6 can be increased. By providing the second concave end side surface 223 and the second through hole 230, the bonding strength between the second lead 2 and the sealing resin 6 can be increased. By providing the back surface side recess 361, the eaves section 362, the main surface side intermediate end surface 363, and the main surface side recess 371, the bonding strength between the third lead 3 and the sealing resin 6 can be increased.

17 and 18 show a modification of the semiconductor device A1. Note that in these figures, elements that are the same as or similar to those in the above-mentioned example are given the same reference numerals as in the above-mentioned example.

In the modification shown in FIG. 17, the first terminal portion 112 has one first end surface 121 and two first concave end surfaces 122. The first end surface 121 is arranged between the two first concave end surfaces 122 in the x direction. Such a first terminal portion 112 is formed by using the lead frame 10 shown by imaginary lines in the figure. Also in this modification, the two first concave end surfaces 122 are covered with the first side plating layer 193. Such a modification also makes it possible to increase the mounting strength of the semiconductor device A1.

In the modification shown in FIG. 18, the first terminal portion 112 has one first end surface 121 and one first concave end surface 122. The first end surface 121 and the first concave end surface 122 are aligned in the x direction. Such a first terminal portion 112 is formed by using the lead frame 10 shown by imaginary lines in the figure. Also in this modification, the first concave end surface 122 is covered with the first side plating layer 193. Such a modification also makes it possible to increase the mounting strength of the semiconductor device A1.

It goes without saying that the same form as the modification shown in FIGS. 17 and 18 can be applied to the second tip surface 221 and the second concave end surface 222 of the second wire bonding part 211 of the second lead 2. .

The semiconductor device according to the present invention is not limited to the embodiments described above. The specific configuration of each part of the semiconductor device according to the present invention can be changed in design in various ways.

A1: Semiconductor device 1
1: First lead 2: Second lead 3: Third lead 4: Semiconductor element 6: Sealing resin 10: Lead frame 40: Element body 41: First electrode 42: Second electrode 43: Third electrode 49: Conductive Sealing material 51 : First wire 52 : Second wire 61 : Main surface of sealing resin 62 : Back surface of sealing resin 63 : Side surface of sealing resin 81 : Cutting line 82 : Cutting line 83 : Cutting line 91 : Circuit board 92 : Solder 101 : Principal surface 102 : Back surface 111 : First wire bonding part 112 : First terminal part 115 : First bent part 121 : First tip surface 122 : First concave end surface 123 : First concave end side surface 130 : First Through hole 150 : Outer back surface mounting part 151 : Tip edge 152 : Concave edge 191 : First main surface plating layer 192 : First back surface plating layer 193 : First side plating layer 201 : Main surface 202 : Back surface 211 : First 2-wire bonding part 212 : Second outer terminal part 213 : Second inner terminal part 215 : Second bent part 221 : Second tip surface 222 : Second concave end surface 223 : Second concave end side surface 230 : Second penetration Hole 250 : Outer back mounting part 251 : Second leading edge 252 : Second concave edge 260 : Inner back mounting part 291 : Second main surface plating layer 292 : Second back plating layer 293 : Second side plating layer 301 : Main surface 302 : Back surface 311 : Element bonding part 312 : Terminal-like extension part 313 : Lateral extension part 350 : Element side back surface mounting part 361 : Back side recessed part 362 : Eaves part 363 : Main surface side intermediate end surface 371 : Main surface side recess 391 : Third main surface plating layer 392 : Third back plating layer 393 : Third side plating layer E1 : Area E2 : Area L1 : Dimension L2 : Dimension R1 : Area ratio R2 : Dimension ratio R3 : Ratio S1: Dimension S2: Dimension

Claims (20)

The first lead and
a semiconductor element spaced apart from the first lead in a first direction when viewed in the thickness direction and electrically connected to the first lead;
a second lead having a main surface on which the semiconductor element is mounted; and a sealing resin that covers the semiconductor element and a part of the first lead,
The sealing resin includes a first resin side surface extending in a second direction perpendicular to the first direction when viewed in the thickness direction,
The first lead includes a protrusion and an inner part, the protrusion protrudes from the first resin side surface in the first direction, and the inner part is embedded in the sealing resin,
The inner portion of the first lead includes a wire bonding portion and a bent portion that interconnects the protrusion and the wire bonding portion,
The second lead further includes a back surface facing opposite to the main surface, and an eaves section extending in the first direction toward the first lead, and the eaves section has a top surface of the eaves section. includes a curved surface, and the eave portion is formed between the main surface of the second lead and the back surface of the second lead in the thickness direction,
The first lead has a main surface and a back surface facing opposite to each other in the thickness direction,
The back surface of the first lead is a portion exposed from the sealing resin, and is arranged on one end side in the first direction and is located at the outermost side in the second direction. and an inner back mounting part located inward than the outer back mounting part in the second direction,
In the semiconductor device, the area of the outer back surface mounting portion is larger than the area of the inner back surface mounting portion. 2. The semiconductor device according to claim 1, wherein the eaves section includes a flat surface on the lower side of the eaves section. 3. The semiconductor device according to claim 2, wherein the flat surface of the eave part has a longer length in the first direction than the curved surface of the eave part. The second lead has a main surface side recess that is recessed from the main surface, and the semiconductor element is disposed between the main surface side recess and the eaves section when viewed in the thickness direction. 3. The semiconductor device according to 3. 5. The semiconductor device according to claim 4, wherein a part of the sealing resin is disposed within the main surface side recess. 6. The semiconductor device according to claim 5, wherein the sealing resin covers the flat surface of the eave portion. 7. The semiconductor device according to claim 6, further comprising a third lead disposed adjacent to the first lead, the third lead being electrically connected to a gate electrode of the semiconductor element. 8. The semiconductor device according to claim 7, wherein the first resin side surface is inclined with respect to the first direction. 9. The semiconductor device according to claim 8, wherein the second lead includes a partially expanded portion having a longer length in the second direction than an adjacent portion. 10. The semiconductor device according to claim 9, wherein at least a portion of the wire bonding portion of the inner portion of the first lead is disposed higher than the main surface of the second lead. 3. The semiconductor device according to claim 2, wherein the sealing resin includes a plurality of side surfaces including a lower surface, an upper surface, and the first resin side surface, and the plurality of side surfaces are tapered as a whole from the lower surface. 12. The semiconductor device according to claim 11, wherein the back surface of the second lead is exposed from the lower surface of the sealing resin. 2. The semiconductor device according to claim 1, wherein the main surface of the second lead includes a region exposed from the sealing resin. 3. The semiconductor device according to claim 2, wherein the wire bonding section of the first lead has a main surface and a back surface that are higher than the flat surface of the eave section. 2. The semiconductor device according to claim 1, wherein the bent portion of the first lead has an upper inclined surface having a smaller inclination angle with respect to the first direction than a side surface of the first resin of the sealing resin. The second lead is provided with a flat end portion that is placed on the eaves portion and is placed so as to face the wire bonding portion of the first lead through a part of the sealing resin. Item 1. The semiconductor device according to item 1. The sealing resin includes a second resin side surface opposite to the first resin side surface in the first direction,
2. The semiconductor device according to claim 1, wherein the eave portion is disposed closer to the second resin side surface than the first resin side surface in the first direction. 2. The semiconductor device according to claim 1, wherein the eave portion is elongated in the second direction, and the length in the second direction is longer than the first lead. 2. The semiconductor device according to claim 1, wherein the eave portion is elongated in the second direction, and the length in the second direction is longer than the semiconductor element. 2. The semiconductor device according to claim 1, further comprising a wire that electrically connects the semiconductor element and the wire bonding portion of the first lead, the entire wire being embedded in the sealing resin.

Images