Semiconductor device

Abstract

Provided is a semiconductor device capable of suppressing the formation of flashes and burrs on the lower surface of a die pad in a structure in which the lower surface of the die pad is exposed from a sealing resin. The present invention is provided with: a lead frame comprising a flat chip pad and a lead, the chip pad having, on one main surface, a mounting region in which a semiconductor chip is mounted and having, on a side portion, a protruding portion which protrudes laterally in an eave shape along the one main surface and which has a frame shape in plan view; a semiconductor chip mounted on the mounting region; and a sealing body that covers a side surface of the die pad while exposing the other main surface of the die pad, seals the semiconductor chip on one main surface of the die pad, holds the die pad, and holds the lead. A through-hole is formed in the die pad, the through-hole penetrating the protruding portion in a direction intersecting the one main surface.

Description

Technical Field

[0001] The present invention relates to semiconductor devices. Background Art

[0002] A semiconductor device is disclosed, the semiconductor device comprising a lead frame, a semiconductor chip and a sealing resin, the lead frame including a die pad and leads, the semiconductor chip being mounted on the die pad, and the sealing resin sealing the lead frame and the semiconductor chip. For example, Patent Document 1 discloses a semiconductor device, the lower surface of the die pad of the semiconductor device being exposed from the sealing resin and having a groove portion having a plurality of grooves formed on the lower surface.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-082446 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In the semiconductor device described in Patent Document 1, when a die pad and leads carrying a semiconductor chip are provided on a mold and sealing resin is injected into the mold during manufacture of the semiconductor device, the sealing resin is guided along a groove formed on the lower surface of the die pad.

[0008] However, depending on the pressure when the sealing resin is injected, the sealing resin may flow into portions other than the groove between the mold and the lower surface of the die pad, that is, portions that are originally intended to be exposed from the sealing resin.

[0009] When such a situation occurs, the resin attached to the portion other than the groove on the lower surface of the chip pad solidifies and remains as burrs, thereby reducing the heat dissipation when, for example, the heat generated by the semiconductor chip when the semiconductor chip is driven is dissipated from the lower surface of the chip pad.

[0010] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a semiconductor device capable of suppressing the formation of burrs on the lower surface of a die pad in a structure in which the lower surface of the die pad is exposed from a sealing resin.

[0011] Means used to solve problems

[0012] The semiconductor device of the present invention is characterized in that it comprises: a lead frame, which is composed of a flat chip pad and leads, wherein the chip pad has a mounting area for mounting a semiconductor chip on one main surface and a convex portion on the side, and the convex portion protrudes laterally in an eaves shape along one main surface and is frame-shaped in a top view; a semiconductor chip, which is mounted in the mounting area; and a sealing body, which covers the side of the chip pad while exposing the other main surface of the chip pad, and seals the semiconductor chip on one main surface of the chip pad to hold the chip pad and the leads; a through hole is formed in the chip pad to penetrate the convex portion in a direction intersecting with the main surface of one side. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a top view of the semiconductor device according to Example 1.

[0014] Figure 2 This is a cross-sectional view of the semiconductor device according to the first embodiment.

[0015] Figure 3 This is a cross-sectional view showing a state of resin injection during manufacture of the semiconductor device according to the first embodiment.

[0016] Figure 4 This is a top view of a semiconductor device according to Modification 1 of Embodiment 1.

[0017] Figure 5 This is a top view of a semiconductor device according to a second variation of the first embodiment. DETAILED DESCRIPTION

[0018] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description of the embodiments and the accompanying drawings, substantially the same or equivalent parts are given the same reference numerals.

[0019] [Example 1]

[0020] use Figure 1 and Figure 2 The structure of the semiconductor device 100 according to the first embodiment will be described. Figure 1 is a top view of the semiconductor device 100 . Figure 2 yes Figure 1 FIG. 1 is a cross-sectional view of the semiconductor device 100 along line 2-2. Figure 2 In the figure, the up-down direction is the height direction of the semiconductor device 100. Figure 1 In FIG. 1 , the outer edge of a sealing body 17 to be described later is indicated by a two-dot chain line for ease of viewing, and other components sealed by the sealing body 17 are indicated by solid lines.

[0021] The lead frame 11 includes a die pad 12 for holding a semiconductor chip 15 described later and leads 13 used as wiring when mounting the semiconductor device 100. The lead frame 11 is made of a metal material such as copper (Cu), iron (Fe), or an alloy thereof.

[0022] The die pad 12 is a plate-like body having a rectangular shape in a plan view. The die pad 12 has a convex portion 12C on the side, and the convex portion 12C protrudes laterally along the upper surface 12U in an eave shape and is in a frame shape in a plan view. In other words, the die pad 12 has an eave portion protruding laterally from the side of the die pad 12 along the upper surface 12U. The convex portion 12C is formed in a frame shape in a plan view.

[0023] The die pad 12 is provided with a through hole 12H that penetrates the base 12J of the protrusion 12C in the height direction. In the semiconductor device 100 of the present embodiment, the through hole 12H is a rectangular shape in a plan view with the direction along each side of the die pad 12 as the long side direction, and a plurality of through holes 12H are formed along each side of the die pad 12. In the present embodiment, five through holes 12H are provided along each side of the die pad 12.

[0024] The through hole 12H has a notch 12N that ends at a portion of the upper surface 12U of the die pad 12 that is closer to the inside than the root 12J of the convex portion 12C and does not reach the lower surface 12L of the die pad 12 in the height direction. In the through hole 12H, the portion cut away by the notch 12N is exposed in a plan view (see FIG. Figure 1 ).

[0025] In other words, the through hole 12H is Figure 2 The cross-sectional shape shown is such that the through hole 12H penetrates the base 12J of the convex portion 12C of the die pad 12 and has a step portion at the inner side of the base 12J of the through hole 12H.

[0026] The through hole 12H having such a cross-sectional shape can be formed, for example, by etching the root 12J of the convex portion 12C in the die pad 12 from the upper surface 12U side to an extent that does not reach the lower surface 12L. Alternatively, the through hole 12H can be formed by a method other than etching, such as mechanical processing such as drilling processing.

[0027] On the chip pad 12, as Figure 1 As shown, support bars SB having a rectangular shape in plan view are provided, extending outward from the four corners of the frame-shaped protrusion 12C along the diagonal lines of the die pad 12. The support bars SB are used as guides for injecting a mold resin 17M described later when manufacturing the semiconductor device 100.

[0028] The leads 13 are thin and long plates arranged in a direction along each side of the upper surface 12U of the die pad 12 in a plan view, separated from each other. In other words, the leads 13 are arranged along each side of the die pad 12 in a manner surrounding the die pad 12 in a plan view. Figure 1 In the embodiment, seven leads 13 are arranged on each side.

[0029] Lead 13 Figure 2 As shown, it has: a first parallel portion 13A, which is arranged on one end side, i.e., a side closer to the chip pad 12, and extends in a direction parallel to the upper surface 12U; a second parallel portion 13B, which is on the other end side, i.e., a side farther from the chip pad 12, extends in a direction parallel to the upper surface 12U, and is arranged below the first parallel portion 13A; and an inclined portion 13C, which is inclined to connect the first parallel portion 13A with the second parallel portion 13B.

[0030] The second parallel portion 13B of the lead 13 is a portion that is joined to the printed wiring board using a joining member such as solder when the semiconductor device 100 is mounted on the printed wiring board, for example.

[0031] The semiconductor chip 15 is a semiconductor element such as an IC chip that is rectangular in plan view and made of a semiconductor material such as silicon (Si). The semiconductor chip 15 is mounted on a mounting region (not shown) of the upper surface 12U of the die pad 12 using a bonding member (not shown) such as solder.

[0032] Electrode pads (not shown) are formed on the upper surface of the semiconductor chip 15 according to the number of leads 13, and each electrode pad of the semiconductor chip 15 is electrically connected to each lead 13 via a wire (not shown) made of a metal such as gold (Au) or aluminum (Al).

[0033] The sealing body 17 is a sealing member made of a resin such as epoxy resin, which seals the semiconductor chip 15 mounted on the die pad 12 while holding the die pad 12 and the leads 13 by partially covering the die pad 12 and the leads 13 .

[0034] Specifically, the sealing body 17 covers the side surfaces of the chip pad 12 while exposing the lower surface 12L of the chip pad 12 , seals the semiconductor chip 15 on the upper surface 12U of the chip pad 12 to hold the chip pad 12 , and holds the lead 13 by covering a portion of the first parallel portion 13A of the lead 13 .

[0035] That is, in the semiconductor device 100 , the lower surface 12L of the die pad 12 and the portion of the lead 13 excluding a portion of the first parallel portion 13A are exposed from the sealing body 17 , and the rest are sealed by the sealing body 17 .

[0036] As described above, the semiconductor device 100 receives power from an external power source connected to the printed wiring board, for example, by electrically connecting the second parallel portion 13B of the lead 13 to the printed wiring board.

[0037] In the semiconductor device 100 mounted on the printed wiring substrate, the lower surface 12L of the die pad 12 is exposed from the sealing body 17, so that the heat generated when the semiconductor chip 15 is driven by receiving power can be dissipated to the outside through the lower surface 12L of the die pad 12. That is, the semiconductor device 100 has a structure intended to dissipate the heat generated when the semiconductor chip 15 is driven through the die pad 12.

[0038] Furthermore, for example, the semiconductor device 100 may be heat-dissipated by connecting the lower surface 12L of the die pad 12 to a heat-dissipating structure that dissipates heat to the outside of a device on which the semiconductor device 100 is mounted, via a heat-conductive member such as metal.

[0039] [Mechanism for suppressing the formation of burrs on the lower surface of the chip pad]

[0040] Here, use Figure 1 to Figure 3 Suppression of formation of burrs on the lower surface 12L of the die pad 12 during manufacture of the semiconductor device 100 will be described. Figure 3 It is along Figure 1 The cross-sectional view of the semiconductor device 100 taken along line 3-3 is a cross-sectional view showing a state when the mold resin is injected when the sealing body 17 is formed during the manufacture of the semiconductor device 100.

[0041] like Figure 3 As shown in FIG. 1 , the die pad 12 and the leads 13 on which the semiconductor chip 15 is mounted are held by the mold 21 , and the mold resin 17M, which is the sealing body 17 before curing, is injected.

[0042] Specifically, the die pad 12 carrying the semiconductor chip 15 is disposed on the lower mold 21A of the mold 21, and the leads 13 are fixed in a state of being sandwiched between the upper mold 21B and the lower mold 21A of the mold 21. Then, the mold resin 17M is injected into the sealed space Sp formed by the lower mold 21A and the upper mold 21B, and the mold resin 17M is cured to form the sealed body 17 in the semiconductor device 100.

[0043] The molded resin 17M is, for example, Figure 3As shown by the solid arrow, the molded resin 17M is supplied into the sealed space Sp at a predetermined pressure along the support rod SB via a gate (not shown) provided in the mold 21. The molded resin 17M is injected, for example, from the lower right corner portion of the die pad 12 closer to the gate to the upper left corner portion on the diagonal line of the corner portion.

[0044] As described above, in the semiconductor device 100 of the present embodiment, the through hole 12H is formed in the base 12J of the convex portion 12C of the die pad 12. Thus, when the molded resin 17M is injected into the sealed space Sp, the formation of burrs on the lower surface 12L caused by the molded resin 17M entering the lower surface 12L of the die pad 12 can be suppressed.

[0045] The specific mechanism for suppressing the formation of burrs is described below. When the molded resin 17M is injected into the sealed space Sp, the molded resin 17M enters, for example, the space below the protrusion 12C. For example, when the protrusion 12C of the chip pad 12 does not have a through hole 12H formed therein, the molded resin 17M that has entered the space below the protrusion 12C has almost no place to disperse to the space above the protrusion 12C, so it is possible that the momentum is concentrated on the lower end side of the chip pad 12.

[0046] Therefore, when the through hole 12H is not formed in the convex portion 12C of the die pad 12, there is a concern that the pressure from the molded resin 17M acts on the lower end of the die pad 12, and the resin enters from the lower end between the lower surface 12L of the die pad 12 and the lower mold 21A, and the die pad 12 floats, so that the lower surface 12L is separated from the lower mold 21A. In addition, there is a concern that the resin that enters below the convex portion 12C of the die pad 12 generates a force that pushes the convex portion 12C upward, causing the die pad 12 to float.

[0047] For example, when the injected mold resin 17M enters between the lower surface 12L of the die pad 12 and the lower mold 21A, the mold resin 17M solidifies in this state, and burrs may be formed on the lower surface 12L of the die pad 12 .

[0048] For example, when burrs are formed on the lower surface 12L of the die pad 12, there is a concern that the heat dissipation of the lower surface 12L of the die pad 12 decreases when the semiconductor chip 15 is driven, and the temperature of the semiconductor chip 15 rises, causing a malfunction. In addition, for example, when a large amount of burrs remain on the lower surface 12L of the die pad 12, there is a concern that the effort required to remove the burrs in order to ensure heat dissipation increases.

[0049] According to the semiconductor device 100 of this embodiment, a through hole 12H is formed in the protrusion 12C of the chip pad 12 as described above, so that the pressure acting on the lower end of the chip pad 12 during the injection of the molding resin 17M is dissipated, thereby preventing the molding resin 17M from entering between the lower surface 12L of the chip pad 12 and the lower mold 21A.

[0050] Specifically, in the semiconductor device 100 of the present embodiment, the mold resin 17M is formed by Figure 3 As indicated by the dashed arrow A1, the molded resin 17M can flow from the lower side of the protrusion 12C through the through hole 12H to the upper surface 12U side of the die pad 12 while going around the lower side of the protrusion 12C. As a result, the pressure of the molded resin 17M during injection can be dispersed through the through hole 12H, and the pressure of the molded resin 17M can be prevented from concentrating on the lower end of the die pad 12.

[0051] Therefore, according to the semiconductor device 100 of the present embodiment, the pressure during injection of the mold resin 17M is dispersed, and thus it is possible to prevent the mold resin 17M from entering between the lower surface 12L of the die pad 12 and the lower mold 21A.

[0052] Furthermore, according to the semiconductor device 100 of the present embodiment, as described above, the through hole 12H has the notch 12N that ends at the portion inside the base 12J of the convex portion 12C without reaching the lower surface 12L of the die pad 12 in the height direction.

[0053] Thus, in the semiconductor device 100 of the present embodiment, for example, when the mold resin 17M flows from the upper surface 12U side of the die pad 12 into the through hole 12H, the mold resin 17M is formed by the following steps: Figure 3 As shown by the double-dashed arrow A2, the molded resin 17M collides with the step portion formed by the above-mentioned cutout 12N, that is, the pressure of the molded resin 17M acts in the downward direction in the figure, which can also produce a pushing effect on the chip pad 12 from the upper side.

[0054] Therefore, according to the semiconductor device 100 of the present embodiment, the die pad 12 is pressed from above, so that the lower surface 12L of the die pad 12 is less likely to float from the lower mold 21A, and the mold resin 17M can be prevented from entering the lower surface 12L of the die pad 12 .

[0055] Therefore, according to the semiconductor device 100 of this embodiment, by forming a through hole 12H in the chip pad 12, the pressure of the molded resin 17M supplied from below the protrusion 12C of the chip pad 12 can be dispersed and the pushing effect brought by the molded resin 17M supplied from above the protrusion 12C can be obtained.

[0056] Therefore, according to the semiconductor device 100 of the present embodiment, in the structure in which the lower surface 12L of the die pad 12 is exposed from the sealing body 17 as the sealing resin, it is possible to suppress the formation of burrs on the lower surface 12L of the die pad 12 .

[0057] In the semiconductor device 100 of the present embodiment, the through hole 12H formed in the convex portion 12C of the die pad 12 has a rectangular shape in plan view, but the through hole 12H is not limited thereto and may have other shapes, such as a circle or an ellipse in plan view.

[0058] In the semiconductor device 100 of the present embodiment, the through hole 12H formed in the convex portion 12C of the die pad 12 penetrates the convex portion 12C in the height direction, but may not be formed in the direction perpendicular to the upper surface 12U of the die pad 12 .

[0059] For example, the through hole 12H may be formed obliquely relative to the upper surface 12U of the die pad 12. In addition, for example, the through hole 12H may be formed in such a manner that the diameter of the lower surface 12L side of the die pad 12 is larger than the diameter of the upper surface 12U or in the opposite manner. In other words, the through hole 12H may be formed in a substantially trapezoidal cross-sectional shape.

[0060] That is, the through hole 12H only needs to be formed so as to intersect the upper surface 12U of the die pad 12. When the through hole 12H is formed in this way, the pressure of the molded resin 17M supplied from below the convex portion 12C of the die pad 12 can be dissipated and the pushing effect brought by the molded resin 17M supplied from above the convex portion 12C can be obtained.

[0061] In addition, in the semiconductor device 100 of the present embodiment, five through holes 12H are formed at the protrusion 12C of the chip pad 12 along each side of the chip pad 12 , but this is not limited to this. For example, the number of through holes 12H may be increased or decreased depending on the size of the chip pad 12 .

[0062] In the semiconductor device 100 of the present embodiment, the through holes 12H formed at the convex portion 12C of the die pad 12 are formed along all sides of the die pad 12 in a plan view, but the present invention is not limited to this. For example, the through holes 12H may be formed only on the two sides of the die pad 12 that are closer to the gate for injecting the molding resin 17M, that is, on the two sides of the die pad 12 that are closer to the gate for injecting the molding resin 17M. Figure 1 In the case of FIG. 1 , the through hole 12H is formed only on the right side and the bottom side of the die pad 12 .

[0063] In the semiconductor device 100 of the present embodiment, support bars SB are provided at the four corners of the die pad 12, but support bars SB are not necessarily required. In addition, support bars SB may be provided only at the corners of the die pad 12 closest to the gate.

[0064] In the semiconductor device 100 of the present embodiment, the through hole 12H has a notch 12N that ends in the height direction from a portion of the upper surface 12U of the die pad 12 that is closer to the inside than the root 12J of the convex portion 12C without reaching the lower surface 12L of the die pad 12, but it is not necessary to have the notch 12N. For example, the through hole 12H may be formed at a position away from the root 12J of the convex portion 12C, that is, formed in a manner that only the convex portion 12C is penetrated.

[0065] [Modification 1]

[0066] Hereinafter, a first modification of the semiconductor device 100 according to the first embodiment will be described. Figure 4 1 is a plan view of a semiconductor device 110 according to Modification 1. The semiconductor device 110 is different from that of Embodiment 1 in the shape of a through hole 12H, but is the same as that of Embodiment 1 in other respects.

[0067] In the semiconductor device 110 of the present modification, the through hole 12H is in a rectangular shape whose long side direction is along the sides of the semiconductor chip 15 , and the length of the long side direction is the same as the length of the side of the semiconductor chip 15 .

[0068] That is, in the semiconductor device 110, one through hole 12H is formed along each side of the semiconductor chip 15. Therefore, in the semiconductor device 110 of this modification, the through hole 12H has a larger area than the through hole 12H described in the first embodiment.

[0069] When the through hole 12H is formed in this way, by also forming the through hole 12H in the chip pad 12, the pressure of the molded resin 17M supplied from below the protrusion 12C of the chip pad 12 can be dispersed and the pushing effect brought by the molded resin 17M supplied from above the protrusion 12C can be obtained.

[0070] Therefore, according to the semiconductor device 110 of the present modification, similarly to the first embodiment, in the structure in which the lower surface 12L of the die pad 12 is exposed from the sealing body 17 , it is possible to suppress the formation of burrs on the lower surface 12L of the die pad 12 .

[0071] In the semiconductor device 110 of the present modification, the through holes 12H may be formed continuously. That is, the through holes 12H may be formed in a frame shape in a plan view.

[0072] [Modification 2]

[0073] Next, a second modification of the semiconductor device 100 according to the first embodiment will be described. Figure 5 1 is a plan view of a semiconductor device 120 according to Modification 2. The semiconductor device 120 is different from that of Embodiment 1 in the shape of a through hole 12H, but is the same as that of Embodiment 1 in other respects.

[0074] In the semiconductor device 120 of this modification, the through hole 12H has the opposite longitudinal and lateral directions to those of the through hole 12H shown in Example 1. That is, in the semiconductor device 120, the through hole 12H has the longitudinal direction perpendicular to the direction along the side of the die pad 12.

[0075] When the through hole 12H is formed in this way, by also forming the through hole 12H in the chip pad 12, the pressure of the molded resin 17M supplied from below the protrusion 12C of the chip pad 12 can be dispersed and the pushing effect brought by the molded resin 17M supplied from above the protrusion 12C can be obtained.

[0076] Therefore, according to the semiconductor device 120 of the present modification, similarly to the first embodiment, in the structure where the lower surface 12L of the die pad 12 is exposed from the sealing body 17 , it is possible to suppress the formation of burrs on the lower surface 12L of the die pad 12 .

[0077] Description of Reference Numerals

[0078] 100, 110, 120 semiconductor devices

[0079] 11 Lead frame

[0080] 12 chip pads

[0081] 13 Leads

[0082] 15Semiconductor Chips

[0083] 17 Sealing body

[0084] 21 Mould

Claims

1. A semiconductor device, characterized in that: have: A lead frame, comprising a flat chip pad and leads, wherein the chip pad has a mounting area for mounting a semiconductor chip on one main surface and a convex portion on a side portion, wherein the convex portion protrudes laterally in an eave shape along the main surface of the first main surface and has a frame shape in a plan view; The semiconductor chip is mounted in the aforementioned mounting area; as well as a sealing body that covers the side surface of the die pad while exposing the other main surface of the die pad, and seals the semiconductor chip on the one main surface of the die pad to hold the die pad and the lead; The die pad is provided with a through hole penetrating the protrusion in a direction intersecting the one main surface.

2. The semiconductor device according to claim 1, wherein The through hole is formed so as to penetrate a portion of a base of the convex portion.

3. The semiconductor device according to claim 2, wherein: The through hole includes a cutout portion that ends from a portion of the one main surface of the die pad that is located inside a base of the protrusion without reaching the other main surface of the die pad.

4. The semiconductor device according to claim 1 or 2, wherein: The through hole penetrates the convex portion in a direction perpendicular to the one main surface.

5. The semiconductor device according to claim 1 or 2, wherein: A plurality of the through holes are formed along the outer edge of the semiconductor chip in a plan view when the one main surface is viewed from above.

6. The semiconductor device according to claim 5, wherein: The semiconductor chip is rectangular in top view; The through hole is in a rectangular shape with the direction along each side of the semiconductor chip as the long side direction.

7. The semiconductor device according to claim 5, wherein: The semiconductor chip is rectangular in top view; The through hole is in a rectangular shape with the longitudinal direction being a direction perpendicular to the direction along each side of the semiconductor chip.

8. The semiconductor device according to claim 1 or 2, wherein: The semiconductor chip is rectangular in top view; The through hole is in a rectangular shape with the direction along each side of the semiconductor chip as the long side direction, and the length of the long side direction is the same as the length of the side of the semiconductor chip.

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