Lead frame and method for manufacturing the same

Abstract

To provide a lead frame and a method for manufacturing the same that, when the lead frame is sealed with sealing resin, prevent the resin from going around and being filled on a lead frame body.SOLUTION: A lead frame 10 for a semiconductor device comprises: a lead frame body 11 having a first surface 11a and a second surface 11b; and a first resin part 17 arranged on the lead frame body 11. The lead frame body 11 has a first area A1, a second area A2, and a third area A3 arranged in order along a surface direction of the first surface 11a and the second surface 11b. The first area A1, second area A2, and third area A3 are reduced in thickness from a side of the first surface 11a. The thickness T3 of the third area A3 is larger than the thickness T1 of the first area A1, and the first resin part 17 is located in the second area A2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a lead frame and a method for manufacturing the same. [Background technology]

[0002] In recent years, some semiconductor devices used in, for example, electrical equipment for large currents have a plurality of semiconductor elements with different thicknesses mounted on a lead frame (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-40113 Summary of the Invention [Problem to be solved by the invention]

[0004] Such lead frames have stepped portions of different thicknesses for mounting semiconductor elements of different thicknesses, which poses a problem when sealing the lead frame with sealing resin, for example, in that the resin does not easily reach the stepped portions.

[0005] The present disclosure provides a lead frame and a manufacturing method thereof that can prevent the resin from becoming difficult to flow onto the lead frame body when sealing the lead frame with sealing resin. [Means for solving the problem]

[0006] The embodiments of the present disclosure relate to the following [1] to

[12] .

[0007] [1] A lead frame for a semiconductor device, comprising: a lead frame body having a first surface and a second surface opposite to the first surface; and a first resin portion arranged in the lead frame body, wherein the lead frame body has a first region, a second region, and a third region arranged in that order along the surface direction of the first surface and the second surface, the first region, the second region, and the third region are each thinned from the first surface side, the third region is thicker than the first region, and the first resin portion is located in the second region.

[0008] [2] The lead frame described in [1], wherein the lead frame body has a fourth region located on the opposite side of the second region from the third region, the fourth region is thinned from the first surface side, and a second resin portion is located in the fourth region.

[0009] [3] The lead frame described in [1] or [2], wherein the lead frame body has a fifth region located on the opposite side of the second region from the third region, and the fifth region is not thinned.

[0010] [4] A lead frame described in any one of [1] to [3], wherein the lead frame body has a sixth region located on the opposite side of the second region from the third region, the sixth region is thinned from the first surface side, and a third resin portion is located in the sixth region.

[0011] [5] A lead frame described in any one of [1] to [4], wherein the lead frame body has a seventh region located on the opposite side of the second region from the first region, and the seventh region is not thinned.

[0012] [6] A lead frame described in any one of [1] to [5], wherein a protrusion protruding toward the first surface is formed at the end of the second region on the side of the first region.

[0013] [7] The lead frame according to any one of [1] to [6], wherein the thickness of the second region is the same as the thickness of the first region.

[0014] [8] The lead frame according to any one of [1] to [6], wherein the thickness of the second region is greater than the thickness of the first region.

[0015] [9] The lead frame according to any one of [1] to [6], wherein the thickness of the third region is thinner than the thickness of the second region.

[0016]

[10] The lead frame according to any one of [1] to [6], wherein the thickness of the third region is the same as the thickness of the second region.

[0017]

[11] A lead frame described in any one of [1] to

[10] , further comprising a side wall portion extending in the direction in which the first region, the second region, and the third region are aligned, the side wall portion being integrated with the lead frame main body or the first resin portion.

[0018]

[12] A method for manufacturing a lead frame for a semiconductor device, comprising the steps of: preparing a metal substrate having a first surface and a second surface; etching the metal substrate from the first surface side to thin regions corresponding to the first region, the second region, and the third region of the lead frame body; forming a mask layer in the metal substrate in regions corresponding to the first region and the third region; forming a first resin portion in the metal substrate in the second region not covered by the mask layer; removing the mask layer; etching the metal substrate from the first surface side to further thin the first region and the third region of the lead frame body; and polishing the first resin portion from the first surface side to a predetermined thickness. [Effects of the Invention]

[0019] According to the present disclosure, when sealing a lead frame with sealing resin, it is possible to prevent the resin from becoming difficult to flow onto the lead frame body. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view showing a lead frame according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view (a cross-sectional view taken along line II-II in FIG. 1) showing a lead frame according to an embodiment. [Figure 3A] FIG. 3A is a cross-sectional view showing a lead frame according to a modified example of the embodiment. [Figure 3B] FIG. 3B is a cross-sectional view showing a lead frame according to a modified example of the embodiment. [Figure 4A] FIG. 4A is a perspective view showing a lead frame according to a modified example of the embodiment. [Figure 4B] FIG. 4B is a perspective view showing a lead frame according to a modified example of the embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing a semiconductor device according to an embodiment. [Figure 6] 6(a) to 6(h) are cross-sectional views showing a method for manufacturing a lead frame according to one embodiment. [Figure 7] 7(a) to 7(d) are cross-sectional views showing a method for manufacturing a semiconductor device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] An embodiment will be described with reference to Figures 1 to 7. In the following figures, the same parts are given the same reference numerals, and some detailed descriptions may be omitted.

[0022] In this specification, the X direction refers to the direction in which the first region A1 to the seventh region A7 are arranged. The X direction may be a direction parallel to one side of the lead frame 10 in a plan view. The Y direction is a direction perpendicular to both the X direction and the Z direction. The Y direction may be a direction perpendicular to the side of the lead frame 10 in a plan view. The Z direction refers to a direction parallel to the thickness direction of the lead frame 10. The X direction, Y direction, and Z direction are perpendicular to one another.

[0023] In this specification, half-etching refers to etching a material to be etched partway in its thickness direction. The thickness of the material to be etched after half-etching is, for example, 30% to 85%, preferably 40% to 60%, of the thickness of the material to be etched before half-etching.

[0024] (Lead frame configuration) An outline of a lead frame for a semiconductor device according to this embodiment will be described with reference to Figures 1 and 2. Figures 1 and 2 are diagrams showing the lead frame according to this embodiment.

[0025] The lead frame 10 shown in Figures 1 and 2 is used when manufacturing a semiconductor device 20 (Figure 5). The lead frame 10 includes a lead frame body 11 and a first resin portion 17. The first resin portion 17 is disposed on the lead frame body 11. A second resin portion 18 and a third resin portion 19 may also be disposed on the lead frame body 11.

[0026] The lead frame body 11 has a first surface 11a and a second surface 11b. The second surface 11b is located on the opposite side of the first surface 11a. The first surface 11a faces the side on which a first semiconductor element 21a and a second semiconductor element 21b (described later) are mounted. The first surface 11a faces the side opposite to a mounting board (not shown). The first surface 11a may also be referred to as the "front surface" or "upper surface." The second surface 11b faces the side opposite to the side on which a first semiconductor element 21a and a second semiconductor element 21b (described later) are mounted. The second surface 11b faces the side of a mounting board (not shown). The second surface 11b may also be referred to as the "rear surface" or "lower surface."

[0027] The lead frame body 11 has a first region A1, a second region A2, and a third region A3. The first region A1, the second region A2, and the third region A3 are arranged in this order along the planar direction (X direction) of the first surface 11a and the second surface 11b. The lead frame body 11 also has a fourth region A4 and a fifth region A5. The fourth region A4 and the fifth region A5 are located on the opposite side of the second region A2 with respect to the third region A3. The fourth region A4 and the fifth region A5 do not necessarily have to be provided. The lead frame body 11 also has a sixth region A6 and a seventh region A7. The sixth region A6 is located on the opposite side of the fourth region A4 with respect to the fifth region A5. The seventh region A7 is located on the opposite side of the second region A2 with respect to the first region A1. The sixth region A6 and the seventh region A7 do not necessarily have to be provided.

[0028] As shown in FIG. 1, the first region A1 to seventh region A7 of the lead frame body 11 each extend in a direction (Y direction) perpendicular to the direction in which the first region A1 to seventh region A7 are arranged (X direction). Each of the first region A1 to seventh region A7 has a rectangular shape in a plan view. The resin portions 17 to 19 include a first resin portion 17, a second resin portion 18, and a third resin portion 19. The first resin portion 17, the second resin portion 18, and the third resin portion 19 are also collectively referred to as resin portions 17 to 19. The resin portions 17 to 19 each extend in a direction (Y direction) perpendicular to the direction in which the first region A1 to seventh region A7 are arranged (X direction). Each of the resin portions 17 to 19 has a rectangular shape in a plan view.

[0029] The first area A1 to the seventh area A7 of the lead frame body 11 will be further described.

[0030] The first region A1 is thinned from the first surface 11a side. The first region A1 is not thinned from the second surface 11b side. The first region A1 may be a region on which a first semiconductor element 21a (described later) is mounted. The resin portions 17-19 are not provided in the first region A1. The surface of the first region A1 on the first surface 11a side is exposed to the outside. A curved surface 11c is formed at an end of the first region A1 on the seventh region A7 side. A curved surface 11d is formed at an end of the first region A1 on the second region A2 side. The thickness T1 of the first region A1 may be 20% or more and 85% or less of the maximum thickness T0 of the lead frame body 11.

[0031] The second region A2 is directly adjacent to the first region A1. The second region A2 is thinned from the first surface 11a side. The second region A2 is not thinned from the second surface 11b side. The first resin portion 17 is located in the second region A2. The surface of the second region A2 on the first surface 11a side is covered with the first resin portion 17. A protrusion 11e is formed at the end of the second region A2 on the first region A1 side. The protrusion 11e protrudes toward the first surface 11a side. A curved surface 11f is formed on the first surface 11a side of the protrusion 11e. The curved surface 11f is formed on the second region A2 side of the protrusion 11e. This improves adhesion between the second region A2 and the first resin portion 17. The thickness T2 of the second region A2 may be 20% or more and 60% or less of the maximum thickness T0 of the lead frame body 11.

[0032] The third region A3 is directly adjacent to the second region A2. The third region A3 is thinned from the first surface 11a side. The third region A3 is not thinned from the second surface 11b side. The third region A3 may be a region where a second semiconductor element 21b (described later) is mounted. The resin portions 17-19 are not provided in the third region A3. The surface of the third region A3 on the first surface 11a side is exposed to the outside. The thickness T3 of the third region A3 may be 20% or more and 60% or less of the maximum thickness T0 of the lead frame body 11.

[0033] The fourth region A4 is directly adjacent to the third region A3. The fourth region A4 is thinned from the first surface 11a side. The fourth region A4 is not thinned from the second surface 11b side. The second resin portion 18 is located in the fourth region A4. The surface of the fourth region A4 on the first surface 11a side is covered with the second resin portion 18. A curved surface 11g is formed at the end of the fourth region A4 on the fifth region A5 side. The thickness T4 of the fourth region A4 may be 20% or more and 60% or less of the maximum thickness T0 of the lead frame body 11.

[0034] The fifth region A5 is directly adjacent to the fourth region A4. The fifth region A5 is not thinned from either the first surface 11a or the second surface 11b. The fifth region A5 serves as a reference when adjusting the position of the lead frame 10 in the thickness direction. The fifth region A5 also serves as a portion for dissipating heat from the first semiconductor element 21a and the second semiconductor element 21b. The fifth region A5 has a pair of side surfaces 11h, 11i. One side surface 11h faces the fourth region A4. The one side surface 11h is in close contact with the second resin portion 18. The other side surface 11i faces the sixth region A6. The other side surface 11i is in close contact with the third resin portion 19. The thickness T5 of the fifth region A5 is the same as the maximum thickness T0 of the lead frame body 11.

[0035] The sixth region A6 is directly adjacent to the fifth region A5. The sixth region A6 is thinned from the first surface 11a side. The sixth region A6 is not thinned from the second surface 11b side. The sixth region A6 may be located at the extreme end (the end on the positive side in the X direction) of the lead frame body 11. A third resin portion 19 is provided in the sixth region A6. The surface of the sixth region A6 on the first surface 11a side is covered with the third resin portion 19. A curved surface 11j is formed at the end of the sixth region A6 on the fifth region A5 side. The thickness T6 of the sixth region A6 may be 20% or more and 60% or less of the maximum thickness T0 of the lead frame body 11.

[0036] The seventh region A7 is directly adjacent to the first region A1. The seventh region A7 is not thinned from either the first surface 11a or the second surface 11b. The seventh region A7 may be located at the extreme end (the end on the negative X-direction side) of the lead frame main body 11. The seventh region A7, together with the fifth region A5, serves as a reference when adjusting the position of the lead frame 10 in the thickness direction. The seventh region A7 has a side surface 11k facing the first region A1. The side surface 11k is not in close contact with the resin portions 17-19 and is exposed to the outside. The thickness T7 of the seventh region A7 is the same as the maximum thickness T0 of the lead frame main body 11.

[0037] Next, the relationship between the thicknesses of the first region A1 to the seventh region A7 will be described.

[0038] The thickness T1 of the first region A1 may be the thinnest in the lead frame body 11. The thickness T2 of the second region A2 may be thicker than the thickness T1 of the first region A1, but the thickness T1 of the first region A1 may be the same as the thickness T2 of the second region A2. The thickness T3 of the third region A3 is thicker than the thickness T1 of the first region A1. The thickness T2 of the second region A2 may be the same as the thickness T3 of the third region A3, but may be different from the thickness T3 of the third region A3. The thickness T3 of the third region A3 may be the same as the thickness T4 of the fourth region A4, but may be different from the thickness T4 of the fourth region A4. The thickness T5 of the fifth region A5 is thicker than the thickness T3 of the third region A3. The thickness T5 of the fifth region A5 may be the thickest in the lead frame body 11. The thickness T6 of the sixth region A6 is thinner than the thickness T5 of the fifth region A5. The thickness T6 of the sixth region A6 is the same as the thickness T4 of the fourth region A4, but may be different from the thickness T4 of the fourth region A4. The thickness T7 of the seventh region A7 may be the thickest in the lead frame body 11. The thickness T1 of the first region A1 is thinner than the thickness T7 of the seventh region A7. The thickness T7 of the seventh region A7 is the same as the thickness T5 of the fifth region A5.

[0039] Putting all of the above together, the following relationship holds: Note that the magnitude relationship between the values ​​before and after the symbol "," does not matter. T1≦T2, T3, T4, T6 <T5=T7

[0040] The lead frame body 11 may be entirely made of metal. In this case, examples of the metal constituting the lead frame body 11 include copper, copper alloy, 42 alloy (Ni42% Fe alloy), stainless steel, nickel alloy, and Invar material.

[0041] Next, the resin parts 17 to 19 will be described.

[0042] As described above, the resin parts 17 to 19 include the first resin part 17, the second resin part 18, and the third resin part 19. The resin parts 17 to 19 are configured as separate parts, but are not limited to this and may be integrated in whole or in part.

[0043] The first resin portion 17 is located on the second region A2. The first resin portion 17 is fixed to the first surface 11a side of the second region A2. The surface of the first resin portion 17 on the first surface 11a side is flush with the first surface 11a of the lead frame body 11. The surface of the first resin portion 17 on the first surface 11a side is flush with the surfaces of the second resin portion 18 and the third resin portion 19 on the first surface 11a side. The first resin portion 17 has a pair of curved portions 17a, 17b. The pair of curved portions 17a, 17b are formed on the second surface 11b side (negative side in the Z direction) of the first resin portion 17. One curved portion 17a is in close contact with the protrusion portion 11e. The other curved portion 17b faces the third region A3. The maximum thickness T0 of the lead frame body 11 is equal to the sum of the thickness T8 of the first resin portion 17 and the thickness T2 of the second region A2, or is greater than the sum of the thicknesses T8 and T2 (T0≧T2+T8). By pre-filling the second region A2 with the first resin portion 17, it is no longer necessary to wrap the sealing resin 23 between the first region A1 and the third region A3.

[0044] The second resin portion 18 is located on the fourth region A4. The second resin portion 18 is fixed to the first surface 11a side of the fourth region A4. The second resin portion 18 has a pair of curved portions 18a, 18b. The pair of curved portions 18a, 18b is formed on the second surface 11b side (the negative side in the Z direction) of the second resin portion 18. One curved portion 18a faces the third region A3. The other curved portion 18b is in close contact with the lower end of the side surface 11h of the fifth region A5. The maximum thickness T0 of the lead frame main body 11 is equal to or greater than the sum of the thickness T9 of the second resin portion 18 and the thickness T4 of the fourth region A4 (T0≧T4+T9). By pre-filling the fourth region A4 with the second resin portion 18, it is not necessary to wrap the sealing resin 23 around the corners of the lead frame main body 11.

[0045] The third resin portion 19 is located on the sixth region A6. The third resin portion 19 is fixed to the first surface 11a side of the sixth region A6. The third resin portion 19 has a curved portion 19a. The curved portion 19a is formed on the second surface 11b side (the negative side in the Z direction) of the third resin portion 19. The curved portion 19a is in close contact with the lower end of the side surface 11i of the fifth region A5. The maximum thickness T0 of the lead frame body 11 is equal to the sum of the thickness T10 of the third resin portion 19 and the thickness T6 of the sixth region A6, or is greater than the sum of the thicknesses T10 and T6 (T0≧T6+T10). By pre-filling the sixth region A6 with the third resin portion 19, it is not necessary to wrap the sealing resin 23 around the corners of the lead frame body 11.

[0046] The resin parts 17 to 19 are each made of resin. In this case, the resin material that can be used to form the resin parts 17 to 19 is a thermosetting resin such as a silicone resin or an epoxy resin, or a thermoplastic resin such as a PPS resin.

[0047] Next, modified examples of lead frame 10 according to the present embodiment will be described with reference to Figures 3A, 3B, 4A, and 4B. In Figures 3A, 3B, 4A, and 4B, the same parts as those of lead frame 10 shown in Figures 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0048] As shown in FIG. 3A, the thickness T2 of the second region A2 may be the same as the thickness T1 of the first region A1. The thickness T3 of the third region A3 is thicker than the thickness T1 of the first region A1. The surface of the second region A2 on the first surface 11a side is flush with the surface of the first region A1 on the first surface 11a side. A first step portion 11m is formed between the second region A2 and the third region A3. The first resin portion 17 is fixed to the first surface 11a side of the second region A2. The first resin portion 17 is filled in the first step portion 11m. One curved portion 17a of the first resin portion 17 faces the first region A1 side. The other curved portion 17b of the first resin portion 17 is in close contact with the first step portion 11m. The thickness T2 of the second region A2 may be thicker than the thickness T1 of the first region A1. By filling the first step portion 11m with the first resin portion 17 in advance, it is no longer necessary to make the sealing resin 23 flow around the first step portion 11m.

[0049] As shown in FIG. 3B, the thickness T3 of the third region A3 may be thinner than the thickness T2 of the second region A2 and the thickness T4 of the fourth region A4. The thickness T3 of the third region A3 is thicker than the thickness T1 of the first region A1. The thickness T2 of the second region A2 may be the same as the thickness T4 of the fourth region A4. The thickness T2 of the second region A2 is thicker than the thickness T1 of the first region A1. A second step portion 11n is formed between the second region A2 and the third region A3. The first resin portion 17 is fixed to the first surface 11a side of the second region A2. The first resin portion 17 is not filled in the second step portion 11n. One curved portion 17a of the first resin portion 17 is in close contact with the protrusion portion 11e. The other curved portion 17b of the first resin portion 17 faces the third region A3. A third step portion 11o is formed between the third region A3 and the fourth region A4. The second resin portion 18 is fixed to the first surface 11a side of the fourth region A4. The second resin portion 18 is not filled in the third step portion 11o. One curved portion 18a of the second resin portion 18 faces the third region A3. The other curved portion 18b of the second resin portion 18 is in close contact with the curved surface 11g of the fifth region A5. Because the thickness T3 of the third region A3 is thinner than the thickness T2 of the second region A2, a thicker second semiconductor element 21b can be mounted in the third region A3.

[0050] As shown in FIGS. 4A and 4B, the lead frame 10 may have sidewalls 15a and 15b. The sidewalls 15a and 15b are provided to surround the first region A1 and the third region A3. The sidewalls 15a and 15b extend parallel to the direction in which the first region A1 to the seventh region A7 are arranged (the X direction). The upper surfaces of the sidewalls 15a and 15b may be located on the same plane as the first surface 11a of the leadframe body 11. Alternatively, a portion of the leadframe body 11, corresponding to at least the thickness T1 of the first region A1, may be located on the second surface 11b side, and the sidewalls 15a and 15b may be formed on this portion. The lower surfaces of the sidewalls 15a and 15b may be located on the same plane as the second surface 11b of the leadframe body 11.

[0051] 4A, the sidewalls 15a and 15b may be formed from a part of the leadframe body 11. In this case, the sidewalls 15a and 15b are formed from the same metal as the metal forming the leadframe body 11. The sidewalls 15a and 15b are integrated with the first region A1 to the seventh region A7 of the leadframe body 11.

[0052] 4B, the sidewalls 15a and 15b may be made of resin. In this case, the sidewalls 15a and 15b are made of the same resin as the resin that makes up the resin parts 17 to 19. Alternatively, at least a portion of the leadframe body 11 corresponding to the thickness T1 of the first region A1 may be present on the second surface 11b side, and the sidewalls 15a and 15b made of resin may be formed on this portion. The sidewalls 15a and 15b are integrated with the resin parts 17 to 19.

[0053] 4A and 4B, the lead frame 10 has sidewalls 15a and 15b. As a result, when the sealing resin 23 is filled into the first region A1 and the third region A3, the sidewalls 15a and 15b function as wall surfaces that receive the sealing resin 23, making it easy to fill the sealing resin 23.

[0054] (Configuration of semiconductor device) Next, a semiconductor device fabricated using the lead frame 10 according to this embodiment will be described with reference to Fig. 5. Fig. 5 is a cross-sectional view showing the semiconductor device according to this embodiment.

[0055] 5 is a power semiconductor device used in, for example, electrical equipment for large currents. As shown in FIG. 5, the semiconductor device 20 includes a lead frame 10, a first semiconductor element 21a, a second semiconductor element 21b, a plurality of pillars (connecting members) 27, a sealing resin 23, and a rewiring layer 28.

[0056] The first semiconductor element 21a is mounted on the first region A1 of the lead frame 10. The first semiconductor element 21a has a plurality of electrodes. The first semiconductor element 21a may be any of various semiconductor elements that have been conventionally used, and is not particularly limited. The first semiconductor element 21a may be a control IC chip on which a drive circuit for the second semiconductor element 21b is formed. The first semiconductor element 21a may also be an integrated circuit such as an ASIC.

[0057] The second semiconductor element 21b is mounted on the third region A3 of the lead frame 10. The second semiconductor element 21b has a plurality of electrodes. The second semiconductor element 21b may be any of various semiconductor elements that have been conventionally used, and is not particularly limited. The second semiconductor element 21b may be a power element. The second semiconductor element 21b may be an integrated circuit such as a MOSFET. The thickness of the second semiconductor element 21b is different from the thickness of the first semiconductor element 21a. The thickness of the second semiconductor element 21b may be thinner than the thickness of the first semiconductor element 21a.

[0058] The pillars 27 are provided on the first semiconductor element 21a and the second semiconductor element 21b, respectively. The pillars 27 electrically connect the electrodes of the first semiconductor element 21a and the redistribution layer 28, respectively. The pillars 27 also electrically connect the electrodes of the second semiconductor element 21b and the redistribution layer 28, respectively. The pillars 27 may also be referred to as connection portions. The pillars 27 are columnar bodies containing a conductive material. The pillars 27 may be made of a metal material with good conductivity, such as copper or aluminum. One end of the pillars 27 is connected to the electrodes of the first semiconductor element 21a or the electrodes of the second semiconductor element 21b, and the other end is connected to the wiring portion of the redistribution layer 28.

[0059] The sealing resin 23 seals the lead frame 10, the first semiconductor element 21a, the second semiconductor element 21b, and the pillars 27. The sealing resin 23 may be a thermosetting resin such as a silicone resin or an epoxy resin, or a thermoplastic resin such as a PPS resin. The sealing resin 23 is formed on the first region A1 and the third region A3 of the lead frame 10. The sealing resin 23 adheres to the first resin portion 17 and the second resin portion 18.

[0060] The rewiring layer 28 may be disposed on the sealing resin 23 and on the first resin portion 17 and the second resin portion 18 of the lead frame 10. The rewiring layer 28 may have an insulating layer located on the sealing resin 23 and a wiring portion disposed on the insulating layer.

[0061] The configuration of the lead frame 10 is similar to that shown in FIGS. 1 and 2, and therefore a detailed description thereof will be omitted here.

[0062] (Lead frame manufacturing method) Next, a method for manufacturing the lead frame 10 shown in Figures 1 and 2 will be described with reference to Figures 6(a) to 6(h). Figures 6(a) to 6(h) are cross-sectional views (figures corresponding to Figure 2) showing the method for manufacturing the lead frame 10.

[0063] First, as shown in FIG. 6(a), a flat metal substrate 31 is prepared. The metal substrate 31 has a first surface 31a and a second surface 31b. The first surface 31a and the second surface 31b of the metal substrate 31 correspond to the first surface 11a and the second surface 11b of the lead frame body 11, respectively. The metal substrate 31 may be made of a metal such as copper, a copper alloy, or a 42 alloy (a 42% Ni-Fe alloy). It is preferable to use a metal substrate 31 whose both surfaces have been degreased and cleaned.

[0064] Next, photosensitive resist is applied to the entire first surface 31a and second surface 31b of the metal substrate 31, respectively, and dried. Subsequently, the photosensitive resist on the metal substrate 31 is exposed to light through a photomask and developed. This forms etching resist layers 32, 33 (FIG. 6(b)). The etching resist layer 32 on the first surface 31a side has openings 32b. The etching resist layer 33 on the second surface 31b side does not have openings, but may have openings. Note that the etching resist layers 32, 33 may be made of, for example, dry film resist.

[0065] Next, the metal substrate 31 is subjected to a first etching process (FIG. 6(c)). Specifically, the metal substrate 31 is etched with an etchant using the etching resist layers 32 and 33 as a corrosion-resistant film. The etchant can be selected appropriately depending on the material of the metal substrate 31 used. For example, when copper is used as the metal substrate 31, a ferric chloride aqueous solution is usually used as the etchant, and spray etching may be performed on both sides of the metal substrate 31. As a result, the metal substrate 31 is partially thinned from the first surface 31a side by half etching. Specifically, the regions of the metal substrate 31 corresponding to the first region A1, second region A2, third region A3, fourth region A4, and sixth region A6 of the lead frame body 11 are thinned. The regions of the metal substrate 31 corresponding to the fifth region A5 and seventh region A7 of the lead frame body 11 are not thinned and maintain the original thickness of the metal substrate 31.

[0066] At this time, thicknesses T1a, T3a of the regions corresponding to the first region A1 and the third region A3 are respectively thicker than thicknesses T1, T3 of the first region A1 and the third region A3 of the completed lead frame body 11 (T1a>T1, T3a>T3). On the other hand, thicknesses T2a, T4a, T6a of the regions corresponding to the second region A2, the fourth region A4, and the sixth region A6 are respectively substantially the same as thicknesses T2, T4, T6 of the second region A2, the fourth region A4, and the sixth region A6 of the completed lead frame body 11 (T2a=T2, T4a=T4, T6a=T6).

[0067] When etching the metal substrate 31, a protective layer 37 may be provided on the etching resist layer 33 on the second surface 31b side. The protective layer 37 may be masking tape. The protective layer 37 serves as a cushioning material when forming the mask layer 38, which will be described later. By providing the protective layer 37, it is possible to prevent unevenness from occurring on the second surface 31b side when forming the mask layer 38.

[0068] Next, a mask layer 38 is formed on the etching resist layer 32 on the first surface 31a side of the metal substrate 31 (FIG. 6(d)).

[0069] The mask layer 38 is selectively formed in regions of the metal substrate 31 corresponding to the first region A1 and the third region A3 of the lead frame body 11. The mask layer 38 is not formed in regions of the metal substrate 31 corresponding to the second region A2, the fourth region A4, the fifth region A5, and the sixth region A6 of the lead frame body 11. The mask layer 38 may be formed by a printing method or a patterning method. Alternatively, a metal mask or a mesh mask may be used as the mask layer 38.

[0070] Next, resin portions 17 to 19 are formed on the metal substrate 31 in areas not covered by the mask layer 38 (FIG. 6(e)).

[0071] The resin portions 17-19 are formed in regions corresponding to the second region A2, the fourth region A4, and the sixth region A6 of the lead frame body 11, respectively. The resin portions 17-19 are not formed in regions covered by the mask layer 38. That is, the resin portions 17-19 are not formed in regions corresponding to the first region A1 and the third region A3 of the lead frame body 11. The resin portions 17-19 may be formed on the first surface 31a of the metal substrate 31 by, for example, an inkjet method or a screen printing method using a thermosetting resin or a thermoplastic resin. In this case, the resin portions 17-19 are filled in the recesses corresponding to the second region A2, the fourth region A4, and the sixth region A6, respectively. In this case, the second resin portion 18 and the third resin portion 19 may be integrated with each other. The resin portions 17-19 may partially cover the etching resist layer 32 on the first surface 31a.

[0072] Next, the mask layer 38 is removed (FIG. 6(f)). As a result, the regions corresponding to the first region A1 and the third region A3 of the lead frame body 11 are exposed to the outside. Also, the protective layer 37 is removed from the second surface 11b side of the metal substrate 31.

[0073] Next, the metal substrate 31 is subjected to a second etching process (FIG. 6(g)). Specifically, the metal substrate 31 is etched with an etchant using the resin parts 17-19 and the etching resist layers 32, 33 as corrosion-resistant films. The etchant may be the same as that used in the first etching process (FIG. 6(c)). This causes the metal substrate 31 to be further thinned from the first surface 31a side. Specifically, the first region A1 and the third region A3 of the lead frame body 11 are further thinned within the metal substrate 31. At this time, the thicknesses of the regions corresponding to the first region A1 and the third region A3 of the lead frame body 11 become substantially the same as the thicknesses T1 and T3 of the first region A1 and the third region A3 of the completed lead frame body 11, respectively. It should be noted that the areas of the metal substrate 31 corresponding to the second area A2, the fourth area A4, the fifth area A5, the sixth area A6 and the seventh area A7 of the lead frame body 11 are not thinned.

[0074] At this time, the metal portion 31c of the metal substrate 31 located between the region corresponding to the first region A1 and the region corresponding to the second region A2 is removed. As a result, the first resin portion 17 is exposed on the first region A1 side. Also, the metal portion 31d of the metal substrate 31 located between the region corresponding to the second region A2 and the region corresponding to the third region A3 is removed. As a result, the first resin portion 17 is exposed on the third region A3 side. Also, the metal portion 31e of the metal substrate 31 located between the region corresponding to the third region A3 and the region corresponding to the fourth region A4 is removed. As a result, the second resin portion 18 is exposed on the third region A3 side.

[0075] Next, the resin portions 17-19 are polished from the first surface 31a side to a predetermined thickness to expose the first surface 31a of the metal substrate 31 (FIG. 6(h)). Specifically, the resin portions 17-19 are polished from the first surface 31a side until the first surface 31a (11a) of the metal substrate 31 is exposed, and polishing of the resin portions 17-19 is completed. At this time, the metal surfaces located in the fifth region A5 and the seventh region A7 of the lead frame body 11 are exposed. At this time, the etching resist layer 32 on the first surface 31a side is also removed. The etching resist layer 33 on the second surface 31b side is also removed. The resin portions 17-19 may be polished by a method similar to back grinding (also called back grinding) used to finish semiconductor elements to a predetermined thickness.

[0076] In this manner, the lead frame 10 shown in FIGS. 1 and 2 is obtained.

[0077] (Method of manufacturing a semiconductor device) Next, a method for manufacturing the semiconductor device 20 shown in FIG. 5 will be described with reference to FIGS. 7(a) to 7(d).

[0078] First, the lead frame 10 is fabricated (FIG. 7(a)) by, for example, the method shown in FIGS. 6(a)-(h).

[0079] Next, the first semiconductor element 21a on which the pillars 27 are formed is mounted on the first region A1 of the lead frame 10. The second semiconductor element 21b on which the pillars 27 are formed is mounted on the third region A3 of the lead frame 10. In this case, the first semiconductor element 21a and the second semiconductor element 21b are each placed and fixed on the lead frame body 11 using an adhesive such as die bonding paste (die attach process) (FIG. 7(b)).

[0080] Next, the sealing resin 23 is formed on the lead frame 10 by injection molding or transfer molding, for example, a thermosetting resin or a thermoplastic resin (FIG. 7(c)). The sealing resin 23 is formed in the first region A1 of the lead frame 10, around the first semiconductor element 21a. The sealing resin 23 is also formed in the third region A3 of the lead frame 10, around the second semiconductor element 21b. In this way, the lead frame 10, the first semiconductor element 21a, the second semiconductor element 21b, and the pillars 27 are sealed. The pillars 27 may be exposed on the first surface 11a side to enable electrical connection to the outside, and thus may be subjected to a surface finishing process using a laser or polishing, together with the adjacent sealing resin 23.

[0081] In the lead frame 10 according to the present embodiment, the resin portions 17 to 19 are formed in advance in the second region A2, the fourth region A4, and the sixth region A6, respectively. That is, it is not necessary to fill the second region A2, the fourth region A4, and the sixth region A6 with the sealing resin 23. This prevents the sealing resin 23 from being filled into portions on the lead frame 10 where the molten resin is difficult to reach when the sealing resin 23 is formed. Examples of such portions where the molten resin is difficult to reach include the circled portions in FIG. 7(c). Specifically, these include (i) the periphery of the protrusion 11e located between the first region A1 and the second region A2, (ii) the periphery of the curved surface 11g located between the fourth region A4 and the fifth region A5, and (iii) the periphery of the curved surface 11j located between the fifth region A5 and the sixth region A6.

[0082] Thereafter, a rewiring layer 28 is formed on the sealing resin 23 and on the first resin portion 17 and the second resin portion 18 of the lead frame 10. The rewiring layer 28 may be formed by, for example, photolithography and plating. In this manner, the semiconductor device 20 shown in FIG. 5 is obtained (FIG. 7(d)).

[0083] According to this embodiment, the first region A1, the second region A2, and the third region A3 are thinned from the first surface 11a side. The thickness T3 of the third region A3 is thicker than the thickness T1 of the first region A1. The first resin portion 17 is located in the second region A2. As described above, this prevents the sealing resin 23 from failing to fill the portions of the lead frame 10 where the molten resin has difficulty flowing when the sealing resin 23 is formed. As a result, the semiconductor device 20 can be manufactured with high quality.

[0084] Furthermore, according to this embodiment, the thickness T3 of the third region A3 is greater than the thickness T1 of the first region A1. As a result, even when a thick first semiconductor element 21a is mounted in the first region A1 and a thin second semiconductor element 21b is mounted in the second region A2, the surface of the first semiconductor element 21a and the surface of the second semiconductor element 21b can be arranged on approximately the same plane. This facilitates wire bonding.

[0085] Furthermore, according to this embodiment, the lead frame body 11 has a fourth region A4 located on the opposite side of the second region A2 with respect to the third region A3. The fourth region A4 is thinned from the first surface 11a side, and the second resin portion 18 is located in the fourth region A4. This prevents the sealing resin 23 from being left unfilled in the fourth region A4, which is an area into which the molten resin has difficulty flowing, when the sealing resin 23 is formed.

[0086] Furthermore, according to this embodiment, the lead frame body 11 has a fifth region A5 located on the opposite side of the second region A2 with respect to the third region A3. The fifth region A5 is not thinned. This allows the fifth region A5 to be used as a reference for positioning the lead frame 10 in the thickness direction (Z direction). Furthermore, heat from the first semiconductor element 21a and the second semiconductor element 21b can be dissipated from the fifth region A5.

[0087] Furthermore, according to this embodiment, the lead frame body 11 has a sixth region A6 located on the opposite side of the fourth region A4 with respect to the fifth region A5. The sixth region A6 is thinned from the first surface 11a side, and the third resin portion 19 is located in the sixth region A6. This makes it possible to prevent the sealing resin 23 from not being filled into the sixth region A6, which is a portion into which the molten resin has difficulty flowing, when the sealing resin 23 is formed.

[0088] Furthermore, according to this embodiment, the lead frame body 11 has a seventh region A7 located on the opposite side of the second region A2 with respect to the first region A1, and the seventh region A7 is not thinned. This allows the seventh region A7 to be used as a reference for positioning the lead frame 10 in the thickness direction (Z direction). This allows for more stable placement of the lead frame 10. Furthermore, when filling the first region A1 with the sealing resin 23, the seventh region A7 functions as a wall surface, making it easy to fill the sealing resin 23.

[0089] Furthermore, according to the present embodiment, a protrusion 11e that protrudes toward the first surface 11a is formed at the end of the second region A2 on the first region A1 side, thereby improving the adhesion between the protrusion 11e and the first resin portion 17.

[0090] It is also possible to combine the multiple components disclosed in the above embodiments and modifications as needed, or to delete some of the components disclosed in the above embodiments and modifications. [Explanation of symbols]

[0091] 10 Lead Frame 11 Lead frame body 11a 1st page 11b Side 2 17 First resin part 18 Second resin part 19 Third Resin Section 20 Semiconductor Devices 21a First semiconductor element 21b second semiconductor element 23 Sealing resin

Claims

1. In a lead frame for a semiconductor device, a lead frame body having a first surface and a second surface opposite the first surface; a first resin portion disposed on the lead frame body, the lead frame body has a first region, a second region, and a third region that are arranged in this order along a surface direction of the first surface and the second surface, the first region, the second region, and the third region are each thinned from the first surface side, The thickness of the third region is greater than the thickness of the first region, The first resin portion is located in the second region of the lead frame.

2. the lead frame body has a fourth region located on the opposite side of the second region with respect to the third region; the fourth region is thinned from the first surface side, The lead frame according to claim 1 , wherein a second resin portion is located in the fourth region.

3. the lead frame body has a fifth region located on the opposite side of the second region with respect to the third region; The lead frame of claim 1 , wherein the fifth region is not thinned.

4. the lead frame body has a sixth region located on the opposite side of the second region with respect to the third region; the sixth region is thinned from the first surface side, The lead frame according to claim 1 , wherein a third resin portion is located in the sixth region.

5. the lead frame body has a seventh region located on an opposite side of the second region with respect to the first region; The lead frame of claim 1 , wherein the seventh region is not thinned.

6. The lead frame according to claim 1 , wherein a protrusion protruding toward the first surface is formed at an end of the second region on the side of the first region.

7. The lead frame of claim 1 , wherein the thickness of the second region is the same as the thickness of the first region.

8. The lead frame according to claim 1 , wherein the thickness of the second region is greater than the thickness of the first region.

9. The lead frame according to claim 1 , wherein the thickness of the third region is smaller than the thickness of the second region.

10. The lead frame of claim 1 , wherein the thickness of the third region is the same as the thickness of the second region.

11. The lead frame of claim 1, further comprising a side wall portion extending in the direction in which the first region, the second region, and the third region are aligned, the side wall portion being integrated with the lead frame main body or the first resin portion.

12. 1. A method of manufacturing a lead frame for a semiconductor device, comprising: providing a metal substrate having a first surface and a second surface; a step of thinning the metal substrate from the first surface side in regions corresponding to the first region, the second region, and the third region of the lead frame body; forming a mask layer in regions of the metal substrate corresponding to the first region and the third region; forming a first resin portion in the second region of the metal substrate that is not covered by the mask layer; removing the mask layer; a step of etching the metal substrate from the first surface side to further thin the first region and the third region of the lead frame body; and polishing the first resin portion from the first surface side by a predetermined thickness.

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