JP2017005009A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a configuration suitable for preventing generations of voids in a mold resin while reducing stress applied to the semiconductor element due to the mold resin in a full-molded semiconductor device.SOLUTION: A semiconductor device comprises: a tabular island 10 in which one face 11 and the other face 12 form the surface and back, respectively, of a plate; a semiconductor element 20 mounted on the one face 11 of the island 10; and a mold resin 30 sealing the one face 11 side of the island 10 and the other face 12 side of the island 10 together with the semiconductor element 20, and a recess part 33 is provided on at least part of a projection region R1 of the semiconductor element 20 on an upper surface 31a of the mold resin 30 in plan view from the one face 11 side of the island 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a semiconductor device in which a semiconductor element is mounted on one surface side of an island, and both plate surface sides of the island are sealed with a mold resin together with the semiconductor element.

  Conventionally, as this type of semiconductor device, a plate-like island in which one surface and the other surface are in a relation of front and back plate surfaces, a semiconductor element mounted on one surface of the island, and one side of the island and the island together with the semiconductor element The one provided with a mold resin for sealing the other surface side has been proposed (see Patent Document 1).

  Such a semiconductor device is called a so-called full mold type because both front and back plate surfaces of the island are sealed with mold resin.

JP-A-2-271648

  By the way, in this full mold type semiconductor device, the thickness of the part on the other surface side of the island of the mold resin is made thinner than the thickness of the part on the one surface side of the island. This is because heat is radiated from the other surface side of the island opposite to the semiconductor element, or the island is thickened so that the island itself has a heat sink function.

  In such a case, the portion of the mold resin on one surface side of the island that seals the semiconductor element is relatively thick, and the stress on the semiconductor element due to the mold resin is likely to increase. Therefore, there are concerns about peeling between the semiconductor element and the mold resin and fluctuations in the characteristics of the semiconductor element due to the stress.

  In addition, mold resin is usually molded by transfer molding, but if the thickness of the mold resin is greatly different between the one side and the other side of the island, the difference in flow cross-sectional area of the mold resin during resin molding will also be growing. Then, during resin molding, the difference in flow rate of the mold resin between the one surface side and the other surface side of the island increases, and voids are likely to occur in the mold resin.

  The present invention has been made in view of the above problems, and in a full mold type semiconductor device, a configuration suitable for suppressing void generation in a mold resin while reducing stress on a semiconductor element due to the mold resin. It aims to be realized.

In order to achieve the above object, according to the invention described in claim 1, the plate-like island (10) in which the one surface (11) and the other surface (12) are in the relationship of the front and back plate surfaces and the one surface of the island are mounted. And a mold resin (30) for sealing one side of the island and the other side of the island together with the semiconductor element,
In a plan view from the one surface side of the island, in the surface (31a) of the portion (31) located on the one surface side of the island of the mold resin, at least part of the projection region (R1) of the semiconductor element has a recess (33 ) Is provided.

  According to this, since the portion of the mold resin existing on the semiconductor element on the one surface side of the island is reduced by the concave portion, the stress on the semiconductor element due to the mold resin is suppressed.

  In addition, the portion of the mold resin located on one side of the island is thin at the concave portion, so the difference in flow cross-sectional area of the mold resin during resin molding between the one side of the island and the other side. Becomes smaller. For this reason, the difference in flow rate of the mold resin on the both surfaces of the island during resin molding is reduced, and it becomes easy to suppress the generation of voids in the mold resin.

  Therefore, according to the present invention, it is possible to realize a configuration suitable for suppressing the generation of voids in the mold resin while reducing the stress applied to the semiconductor element by the mold resin.

  In addition, the code | symbol in the bracket | parenthesis of each means described in the claim and this column is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

1 is a schematic cross-sectional view showing a semiconductor device according to a first embodiment of the present invention. It is a schematic plan view by planar view from the one surface side of the island in FIG. It is a schematic sectional drawing which shows the semiconductor device concerning 2nd Embodiment of this invention. It is a schematic plan view by planar view from the one surface side of the island in FIG. It is a schematic sectional drawing which shows the semiconductor device concerning 3rd Embodiment of this invention. It is a schematic sectional drawing which shows the semiconductor device concerning 4th Embodiment of this invention. It is a schematic plan view which shows the semiconductor device concerning 5th Embodiment of this invention by the planar view from the one surface side of an island. It is a schematic plan view which shows the semiconductor device concerning 6th Embodiment of this invention by the planar view from the one surface side of an island. It is a schematic sectional drawing which shows the semiconductor device concerning other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are given the same reference numerals in the drawings in order to simplify the description.

(First embodiment)
The semiconductor device S1 according to the first embodiment of the present invention will be described with reference to FIGS. This semiconductor device S1 is mounted on a vehicle such as an automobile, for example, and is applied as a device for driving various electronic devices for the vehicle.

  The semiconductor device S1 of the present embodiment is broadly divided into a plate-like island 10 in which one surface 11 and the other surface 12 are in a relation of front and back plates, a semiconductor element 20 mounted on one surface 11 of the island 10, and these And a mold resin 30 for sealing.

  In this embodiment, the island 10 is configured as the island 10 of the lead frame 100. The lead frame 100 has a plate shape in which one surface and the other surface are in a relation of front and back plate surfaces, and has an island 10 as an element mounting portion and a lead terminal 13 for connection to the outside. is there.

  Here, one surface 11 of the island 10 and one surface 14 of the lead terminal 13 correspond to one surface of the lead frame 100, and the other surface 12 of the island 10 and the other surface 15 of the lead terminal 13 are both lead frames. It corresponds to the other surface of 100.

  Here, one surface 11 of the island 10 is a mounting surface for chip mounting, and one surface 14 of the lead terminal 13 is a wire bonding surface. In the present embodiment, as shown in FIG. 1, the one surface 11 of the island 10 and the one surface 14 of the lead terminal 13 are in the same plane and have the same height.

  Here, the island 10 has a rectangular plate shape. The island 10 may have the same plate thickness as that of the lead terminal 13, but here the plate thickness is made larger than that of the lead terminal 13 in order to provide a function as a heat sink (heat storage function).

  The lead frame 100 having the island 10 and the lead terminal 13 is made of a normal lead frame material such as Cu, and the island 10 and the lead terminal 13 are formed by pressing or etching a single plate material. This pattern is formed. The island 10 and the lead terminal 13 are separated by lead cutting after being sealed in the mold resin 30 in a state of being integrally connected with a tie bar or the like.

  The semiconductor element 20 is bonded onto the surface 11 of the island 10 via an adhesive 40 made of solder, Ag (silver) paste, resin, or the like. The semiconductor element 20 is composed of, for example, a microcomputer, a control element, a power element, or the like, and typically has a rectangular plate shape as shown in FIGS.

  The semiconductor element 20 and the one surface 14 of the lead terminal 13 are connected via a bonding wire 50 made of Au (gold), Al (aluminum), Cu (copper), or the like, and are electrically connected to each other. Yes.

  The mold resin 30 is made of a thermosetting resin such as an epoxy resin, and is molded by a transfer mold method using a mold (not shown). Specifically, resin molding is performed by injecting mold resin 30 into the mold from the gate of the mold and venting air with an air vent of the mold. 1 and 2 show a gate portion 30a that is a portion on the gate side during molding and an air vent portion 30b that is a portion on the air vent side.

  In this embodiment, as in a typical full mold type, the mold resin 30 seals the one surface 11 side of the island 10 and the other surface 12 side of the island 10 together with the semiconductor element 20 and the bonding wires 50. .

  As for the lead terminal 13, the connecting portion side of the bonding wire 50 is sealed as the inner lead in the mold resin 30, and a part protrudes from the mold resin 30 as the outer lead.

  In FIG. 2 and each plan view described below, the outer leads protruding from the mold resin 30 at the lead terminals 13 are not shown. Although not shown, the outer leads of the lead terminals 13 are subjected to lead molding such as bending as required for connection to the outside.

  The mold resin 30 has a plate shape in which the stacking direction (vertical direction in FIG. 1) of the semiconductor element 20 and the island 10 is a plate thickness. Here, the one-surface side resin portion 31 that is a portion of the mold resin 30 that is located on the one surface 11 side of the island 10 is a portion that is located above the one surface 11 of the island 10 as indicated by a double arrow in FIG. It is.

  The length of the double-pointed arrow indicating the one-side resin part 31 corresponds to the thickness of the one-side resin part 31 as it is. Further, in the mold resin 30, the surface of the one-surface side resin portion 31 that appears in a plan view from the one surface 11 side of the island 10 is defined as an upper surface 31 a of the mold resin 30.

  On the other hand, the other surface side resin part 32 which is a part located in the other surface 12 side of the island 10 in the mold resin 30 is lower than the other surface 12 of the island 10 as shown by a double arrow in FIG. It is a part to be located. The length of the double-pointed arrow indicating the other surface side resin portion 32 corresponds to the thickness of the other surface side resin portion 32 as it is.

[About recessed parts]
In such a semiconductor device S1, in the present embodiment, at least one of the projection regions R1 of the semiconductor element 20 on the surface of the one-surface-side resin portion 31 in the mold resin 30 in a plan view from the one surface 11 side of the island 10. A recess 33 is provided in the part.

  In other words, when the semiconductor device S <b> 1 is viewed from a direction orthogonal to the one surface 11 of the island 10, the concave portion 33 is formed in the projection region R <b> 1 of the semiconductor element 20 in which the semiconductor element 20 is projected onto the upper surface 31 a of the mold resin 30. Is provided. More specifically, the concave portion 33 located on the upper surface 31a and the semiconductor element 20 inside the mold resin 30 are arranged so as to overlap each other in plan view from the one surface 11 side of the island 10.

  In the example of FIGS. 1 and 2, the concave portion 33 is a concave portion having a rectangular planar shape (opening shape) and a cross-sectional shape, and more specifically, a concave portion having a rectangular parallelepiped space shape. Here, although the recess 33 and the semiconductor element 20 are both planar rectangles, the shapes and sizes of the rectangles are different, and the recess 33 is disposed so as to overlap with a part of the projection region R1 of the semiconductor element 20. Has been.

  Of course, the recess 33 may be disposed in the entire projection region R1 of the semiconductor element 20 by appropriately changing the planar shape and the planar size of the recess 33. Such a concave portion 33 is formed at the time of resin molding by forming a convex portion corresponding to the concave portion 33 in a mold for molding the mold resin 30.

  As shown in FIGS. 1 and 2, the recess 33 is recessed with a step on the upper surface 31 a of the mold resin 30, and FIGS. 1 and 2 show the corners on the opening side of the recess 33. A portion 33a and a corner 33b on the bottom side are shown. Here, the planar patterns of the respective corner portions 33a and 33b are both planar rectangles corresponding to the opening and bottom of the recess 33.

  The corner 33a on the opening side is a corner as an intersection between the upper surface 31a and the side surface of the recess 33, and the corner 33b on the bottom side is a corner as an intersection between the side surface of the recess 33 and the bottom surface. It is. Moreover, although not limited, the depth of the recessed part 33 can be made into about several tens of micrometers-several mm, for example.

[Effects]
By the way, according to the present embodiment, the portion existing on the semiconductor element 20 in the one-surface-side resin portion 31 in the mold resin 30 is reduced by the amount of the concave portion 33, and thus the semiconductor caused by the mold resin 30. The stress on the element 20 is suppressed.

  Further, since the thickness of the one side resin portion 31 of the mold resin 30 is reduced at the concave portion 33, the flow of the mold resin 30 during resin molding is reduced between the one surface 11 side and the other surface 12 side of the island 10. The difference in area is reduced. Therefore, the flow rate difference of the mold resin 30 on both plate surfaces of the island 10 during resin molding is reduced, and it becomes easy to suppress the generation of voids in the mold resin 30.

  Therefore, according to the present embodiment, it is possible to realize a configuration suitable for suppressing the generation of voids in the mold resin 30 while reducing the stress applied to the semiconductor element 20 by the mold resin 30.

  In the case of the full mold type as in this embodiment, as described above, the thickness of the other surface side resin portion 32 of the mold resin 30 is made thinner than the thickness of the one surface side resin portion 31. Therefore, normally, the semiconductor device S1 is likely to warp so that the entire device protrudes upward in FIG. 1 in the thickness direction of the mold resin 30.

  However, in this embodiment, the difference in the thickness of the mold resin 30 on both plate surfaces of the island 10 can also be reduced by the recess 33, so that the warp of the semiconductor device S1 in the thickness direction of the mold resin 30 can be easily suppressed. You can also expect the effect.

(Second Embodiment)
A semiconductor device S2 according to the second embodiment of the present invention will be described with reference to FIGS. This embodiment is different from the first embodiment in the planar shape of the recess 33, and here, the difference will be mainly described.

  In the first embodiment, the concave portion 33 and the semiconductor element 20 have different planar shapes and planar sizes, and the concave portion 33 is disposed so as to overlap with a part of the projection region R1 of the semiconductor element 20 (FIG. 1, FIG. 2).

  In the present embodiment, the concave portion 33 is provided on the surface (that is, the upper surface 31a) of the one surface side resin portion 31 in the mold resin 30 in a plan view from the one surface 11 side of the island 10. This is the same as in the first embodiment.

  However, in the present embodiment, as shown in FIGS. 3 and 4, the recess 33 includes the entire projection region R1 of the semiconductor element 20 on the upper surface 31a and is provided in a wider range than the projection region R1. Yes. In the illustrated example, the planar shape of the recess 33 is a rectangle that is slightly larger than the projection region R <b> 1 of the semiconductor element 20.

  When the concave portion 33 is provided on the upper surface 31a of the mold resin 30, the corner portion 33a on the opening portion side and the corner portion 33b on the bottom portion side exist in the concave portion 33 due to the step of the concave portion 33 as described above. Here, these corner portions constitute the outline of the concave portion 33, but are portions where stress tends to concentrate in the mold resin 30 because of the shape thereof.

  On the other hand, in the present embodiment, the planar size of the concave portion 33 includes the entire projection region R1 of the semiconductor element 20, and the outline of the concave portion 33 is positioned outside the projection region R1 of the semiconductor element 20. . Therefore, the corners 33 a and 33 b in the recess 33 are also located outside the projection region R 1 of the semiconductor element 20.

  For this reason, according to the present embodiment, it is possible to suppress the influence of the stress concentrated on the corner portions 33a and 33b on the semiconductor element 20 as much as possible, and the stress applied to the semiconductor element 20 by the mold resin 30 can be reduced. A preferred configuration is provided in terms of reduction.

(Third embodiment)
A semiconductor device S3 according to a third embodiment of the present invention will be described with reference to FIG. This embodiment is different from the first embodiment in the planar shape of the recess 33, and here, the difference will be mainly described.

  In the first embodiment, the recess 33 and the semiconductor element 20 have different planar shapes and plane sizes, and the recess 33 is disposed so as to overlap a part of the projection region R1 of the semiconductor element 20 (FIGS. 1 and 2). reference).

  In the present embodiment, the concave portion 33 is provided on the surface (that is, the upper surface 31a) of the one surface side resin portion 31 in the mold resin 30 in a plan view from the one surface 11 side of the island 10. This is the same as in the first embodiment.

  However, in the present embodiment, as shown in FIG. 5, the projection region R1 of the semiconductor element 20 and the recess 33 on the upper surface 31a have the same shape and the same size, and the contours thereof are the same. In the illustrated example, the planar shape of the recess 33 and the projection region R1 of the semiconductor element 20 are the same rectangle and are at the same position. Specifically, the length L1 of the concave portion 33 and the length L2 of the semiconductor element 20 in FIG.

  According to the present embodiment, the corners 33a and 33b in the recess 33 can be positioned outside the projection region R1 of the semiconductor element 20, and stress concentrated on the corners as in the second embodiment. Can suppress the influence on the semiconductor element 20 as much as possible.

  In addition, as in the second embodiment, when the concave portion 33 is disposed so as to overlap with a bonding wire or the like around the semiconductor element 20, the thickness of the mold resin 30 that seals the periphery of the semiconductor element 20 is reduced. There is a risk that it will be difficult to secure enough.

  In that respect, according to the present embodiment, it is preferable in terms of reducing the stress applied to the semiconductor element 20 by the mold resin 30 while sufficiently securing the thickness of the mold resin 30 that seals the periphery of the semiconductor element 20. Can be realized.

(Fourth embodiment)
A semiconductor device S4 according to the fourth embodiment of the present invention will be described with reference to FIG. This embodiment differs from the first embodiment in the cross-sectional shape of the recess 33, and here, the difference will be mainly described.

  In the first embodiment, the cross-sectional shape of the concave portion 33 is a rectangle having a uniform width in the depth direction, that is, a rectangular cross-sectional shape (see FIG. 1). On the other hand, as shown in FIG. 6, the concave portion 33 of the present embodiment has a trapezoidal cross-sectional shape whose width becomes narrower in the depth direction.

  Also in this case, the effect by the recessed part 33 similar to the said 1st Embodiment can be anticipated. Furthermore, in the case of the concave portion 33 of the first embodiment, the corner portion 33a on the opening side and the corner portion 33b on the bottom side are both substantially perpendicular, but in this embodiment, these corner portions 33a and 33b are obtuse angles. Therefore, compared with the first embodiment, stress concentration generated in the corner portion is relaxed, which is preferable.

  In the present embodiment, since the cross-sectional shape of the recess 33 is the above trapezoid, in addition to the first embodiment, the second embodiment and the third embodiment are combined. Needless to say, it can be applied.

(Fifth embodiment)
A semiconductor device S5 according to a fifth embodiment of the present invention will be described with reference to FIG. This embodiment is different from the first embodiment in the planar shape of the recess 33, and here, the difference will be mainly described.

  In the first embodiment, the recess 33 has a size that fits on the inner periphery of the upper surface 31a of the mold resin 30 when viewed in plan as shown in FIG. On the other hand, as shown in FIG. 7, the concave portion 33 of the present embodiment penetrates between opposite ends of the upper surface 31 a of the mold resin 30. The same effect as that of the first embodiment can be expected by the recess 33 of the present embodiment.

  Here, in the example of FIG. 7, the concave portion 33 penetrates between both ends in the direction orthogonal to the flow direction of the mold resin 30 during resin molding (that is, the direction from the gate portion 30 a to the air vent portion 30 b) on the upper surface 31 a. doing. However, the present invention is not limited to this. For example, the concave portion 33 may pass through both ends of the upper surface 31a in the flow direction of the mold resin 30 during resin molding.

  In the example of FIG. 7, the recess 33 is disposed so as to overlap the entire projection region R <b> 1 of the semiconductor element 20. However, for example, the recess 33 may be disposed so as to overlap with a part of the projection region R1 of the semiconductor element 20 by reducing the width of the recess 33 (width in the left-right direction in FIG. 7). Further, also in the concave portion 33 of the present embodiment, the cross-sectional shape may be a trapezoid as in the fourth embodiment.

(Sixth embodiment)
A semiconductor device S6 according to a sixth embodiment of the present invention will be described with reference to FIG. The present embodiment is applicable to each of the above embodiments as long as the recesses 33 extend to the outside of the projection region R1 of the semiconductor element 20 on both sides in the flow direction of the mold resin 30 during resin molding. It is what is done.

  As shown in FIG. 8, the recesses 33 are arranged to extend outside the projection region R1 on both sides of the gate part 30a side and the air vent part 30b side along the flow direction of the mold resin 30 described above. Yes.

  Here, in this embodiment, the extending length of the concave portion 33 is not equal on both sides in the flow direction of the mold resin 30, and is longer on the gate portion 30 a side than on the air vent portion 30 b side. By forming the long concave portion 33 on the gate portion 30a side, the flow rate of the mold resin 30 on the one surface 11 side of the island 10 can be reduced on the gate side during resin molding. Is desirable in terms of reducing

(Other embodiments)
In the first embodiment, as shown in FIG. 1, the one surface 11 of the island 10 and the one surface 14 of the lead terminal 13 are on the same plane and have the same height. For example, as shown in FIG. 9, in order to increase the wire bonding efficiency by making the height of the semiconductor element 20 and the lead terminal 13 the same as much as possible, as shown in FIG. The one surface 11 may be lower than the one surface 14 of the lead terminal 13.

  Further, as the island, a separate heat sink may be provided on the other surface 12 side of the island 10 of the lead frame 100 by caulking or the like. That is, the island may have a two-layer structure of the island 10 and the heat sink.

  Furthermore, the island may be formed of a material separate from the lead terminal 13, and for example, a heat sink or a wiring board such as a ceramic board or a printed board may be used. Can be mentioned.

  Further, the planar shape of the recess 33 is not limited to the above-described rectangle, and may be, for example, a circle, a polygon other than a rectangle, or an indefinite shape.

  In the above embodiment, the semiconductor device having the semiconductor element 20 is shown. However, the semiconductor device may have a configuration in which passive components such as a chip resistor and a chip capacitor are sealed in the mold resin 30. Good.

  Further, as a semiconductor device, a full mold type configuration in which a semiconductor element 20 is mounted on one surface 11 of a plate-like island 10 and both the plate surface sides of the island 10 are sealed with a mold resin 30 together with the semiconductor element 20. The lead terminal 13 as described above may not be configured to protrude from the mold resin 30. For example, the lead terminal may be exposed on the same surface as the surface of the mold resin 30. Furthermore, you may employ | adopt wiring members other than a lead terminal for external connection.

  Further, the present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope described in the claims. The above embodiments are not irrelevant to each other, and can be combined as appropriate unless the combination is clearly impossible, and the above embodiments are not limited to the illustrated examples. Absent. In each of the above-described embodiments, it is needless to say that elements constituting the embodiment are not necessarily essential unless explicitly stated as essential and clearly considered essential in principle. Yes. Further, in each of the above embodiments, when numerical values such as the number, numerical value, quantity, range, etc. of the constituent elements of the embodiment are mentioned, it is clearly limited to a specific number when clearly indicated as essential and in principle. The number is not limited to the specific number except for the case. Further, in each of the above embodiments, when referring to the shape, positional relationship, etc. of the component, etc., the shape, unless otherwise specified and in principle limited to a specific shape, positional relationship, etc. It is not limited to the positional relationship or the like.

DESCRIPTION OF SYMBOLS 10 Island 11 One side of island 12 Other side of island 20 Semiconductor element 30 Mold resin 31 One surface side resin part as a part located in one side of island among mold resins 31a Upper surface of mold resin 33 Recessed part R1 Upper surface of mold resin Projection Area of Semiconductor Device in

Claims (3)

A plate-like island (10) in which the one surface (11) and the other surface (12) are in a relation of front and back plate surfaces;
A semiconductor element (20) mounted on one surface of the island;
A mold resin (30) for sealing one side of the island and the other side of the island together with the semiconductor element;
In a plan view from the one surface side of the island, at least a part of the projection region (R1) of the semiconductor element on the surface (31a) of the portion (31) of the mold resin located on the one surface side of the island A semiconductor device comprising a recess (33).   In a plan view from the one surface side of the island, in the surface of the part located on the one surface side of the island of the mold resin, including the entire projection region of the semiconductor element, in a range wider than the projection region, The semiconductor device according to claim 1, wherein the recess is provided.   In a plan view from the one surface side of the island, the projection region of the semiconductor element and the concave portion have the same shape and the same size on the surface of the portion located on the one surface side of the island of the mold resin, 2. The semiconductor device according to claim 1, wherein the outlines of the semiconductor devices coincide with each other.

Images