Semiconductor device and manufacturing method of the semiconductor device

Abstract

To provide a semiconductor device and a manufacturing method of the semiconductor device capable of suppressing formation of flash burrs on a lower surface of a die pad in a configuration in which the lower surface of the die pad is exposed from a sealing resin.SOLUTION: A semiconductor device includes: a lead frame having a mounting region in which a semiconductor chip is mounted on one main surface, the lead frame protruding laterally in an eaves shape along the one main surface, and having a flat plate-shaped die pad and a lead having a frame-shaped convex portion in a side portion in a top 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 to hold the die pad, and holds the lead. The convex portion has an extension portion that is partially provided at a tip of the convex portion and extends downward from the tip.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a semiconductor device and a method for manufacturing the semiconductor device. [Background technology]

[0002] A semiconductor device is disclosed that includes a lead frame including a die pad and leads, a semiconductor chip mounted on the die pad, and a sealing resin that seals the lead frame and the semiconductor chip. For example, Patent Document 1 discloses a semiconductor device in which the lower surface of the die pad is exposed from the sealing resin and has a groove portion in which a plurality of grooves are formed on the lower surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-082446 Summary of the Invention [Problem to be solved by the invention]

[0004] In the semiconductor device described in Patent Document 1, for example, when manufacturing the semiconductor device, a die pad and leads mounted with a semiconductor chip are placed in a mold, and sealing resin is injected into the mold, and the injected sealing resin is guided along a groove formed on the underside of the die pad.

[0005] However, depending on the pressure when the sealing resin is injected, the sealing resin may flow into areas other than the groove between the mold and the underside of the die pad, i.e., areas that should be exposed from the sealing resin.

[0006] If this occurs, the resin adhering to the areas other than the grooves on the underside of the die pad will harden and remain as flash burrs, which will reduce the heat dissipation performance when trying to dissipate heat generated in the semiconductor chip from the underside of the die pad, for example, when the semiconductor chip is operating.

[0007] The present invention has been made in consideration of the above points, and aims to provide a semiconductor device and a method for manufacturing a semiconductor device that can suppress the formation of flash burrs on the underside of a die pad in a configuration in which the underside of the die pad is exposed from the sealing resin. [Means for solving the problem]

[0008] The semiconductor device of the present invention includes a lead frame consisting of a flat die pad and leads, the lead frame having a mounting area on one main surface for mounting a semiconductor chip, the die pad protruding laterally along the one main surface in the shape of an eave and having frame-shaped convex portions on the sides when viewed from above, a semiconductor chip mounted in the mounting area, and a sealing body that covers the side surfaces 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 leads, and is characterized in that the convex portion has an extension portion that is partially provided at the tip of the convex portion and extends downward from the tip. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a top view of a semiconductor device according to a first embodiment. [Figure 2] 1 is a cross-sectional view of a semiconductor device according to a first embodiment. [Figure 3] 1 is a cross-sectional view of a semiconductor device according to a first embodiment. [Figure 4] 4 is a cross-sectional view showing a state in which a resin is injected during the manufacture of the semiconductor device according to the first embodiment. FIG. [Figure 5] FIG. 10 is a top view of a semiconductor device according to a first modified example of the first embodiment. [Figure 6] FIG. 10 is a top view of a semiconductor device according to a second modification of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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 designated by the same reference numerals. [Example]

[0011] The configuration of a semiconductor device 100 according to a first embodiment will be described with reference to Figures 1 to 3. Figure 1 is a top view of the semiconductor device 100. In Figure 1, for ease of viewing, the outer edge of a sealing body 17, which will be described later, is indicated by a two-dot chain line, and other components sealed by the sealing body 17 are indicated by solid lines.

[0012] Fig. 2 is a cross-sectional view of the semiconductor device 100 taken along line 2-2 shown in Fig. 1. Fig. 3 is a cross-sectional view of the semiconductor device 100 taken along line 3-3 shown in Fig. 1. In Figs. 2 and 3, the vertical direction in the drawings corresponds to the height direction of the semiconductor device 100.

[0013] The lead frame 11 is composed of a die pad 12 that holds a semiconductor chip 15 (described later) and leads 13 that are 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 based on these metals.

[0014] The die pad 12 is a plate-like body having a rectangular upper surface. The die pad 12 has a protrusion 12C on its side that protrudes laterally in an eave-like shape along the upper surface 12U and has a frame-like shape in top view (see FIGS. 2 and 3). In other words, the die pad 12 has an eave portion that protrudes laterally from the side of the die pad 12 along the upper surface 12U. The protrusion 12C is formed in a frame shape in top view.

[0015] In the semiconductor device 100 of this embodiment, the protruding portion 12C of the die pad 12 has an extension 12CE provided along the outer edge of the protruding portion 12C at the corner of the protruding portion 12C at the lower right in the drawing, as shown in FIG.

[0016] 2, the extension 12CE is formed continuously from the tip of the protrusion 12C and extends downward from the tip of the protrusion 12C. One end face of the extension 12CE is located on the same plane as the lower surface 12L of the die pad 12.

[0017] The protrusion 12C and the extension 12CE of the die pad 12 can be formed, for example, by etching a flat plate material that serves as the base material of the die pad 12 from the lower surface 12L side. Note that the protrusion 12C and the extension 12CE may be formed by a mechanical engineering method or the like, without being limited to etching.

[0018] As shown in FIG. 1, the die pad 12 is provided with support bars SB, which are plate-like members with a rectangular top surface that extend outward from the four corners of the frame-shaped protrusion 12C along the diagonals of the die pad 12.

[0019] In the semiconductor device 100 of this embodiment, the support bar SB at the lower right in Fig. 1 is connected to the extension 12CE of the protrusion 12C described above. The support bar SB connected to the extension 12CE is used as a guide when injecting a molding resin 17M, which will be described later, during the manufacture of the semiconductor device 100.

[0020] The leads 13 are elongated thin plates that are arranged at a distance from one another in a direction along each side of the upper surface 12U of the die pad 12 in top view. In other words, the leads 13 are arranged along each side of the die pad 12 so as to surround the die pad 12 in top view. In Fig. 1, seven leads 13 are provided on each side.

[0021] As shown in FIG. 3, the lead 13 has a first parallel portion 13A extending in a direction parallel to the upper surface 12U located proximal to the die pad 12, a second parallel portion 13B extending in a direction parallel to the upper surface 12U distal to the die pad 12 and located lower than the first parallel portion 13A, and an inclined portion 13C inclined to connect the first parallel portion 13A and the second parallel portion 13B.

[0022] The second parallel portion 13B of the lead 13 is a portion that is electrically connected to a printed wiring board using a bonding material such as solder when, for example, mounting the semiconductor device 100 on a printed wiring board.

[0023] The semiconductor chip 15 has a rectangular top surface and is a semiconductor element such as an IC chip made of a semiconductor material such as silicon (Si). The semiconductor chip 15 is mounted on a mounting area (not shown) on the top surface 12U of the die pad 12 using a bonding material (not shown) such as solder.

[0024] Electrode pads (not shown) are formed on the upper surface of the semiconductor chip 15 in the number equal to the number of leads 13, and each of the electrode pads of the semiconductor chip 15 and each of the leads 13 are electrically connected via wires (not shown) made of a metal such as gold (Au) or aluminum (Al).

[0025] The sealing body 17 is a sealing member made of a resin such as epoxy resin that partially covers the die pad 12 and the leads 13, thereby holding the die pad 12 and the leads 13 and sealing the semiconductor chip 15 mounted on the die pad 12.

[0026] Specifically, as shown in Figures 2 and 3, the sealing body 17 covers the side of the die pad 12 while exposing the lower surface 12L of the die pad 12 and the end surface of the extension portion 12CE, seals the semiconductor chip 15 on the upper surface 12U of the die pad 12 to hold the die pad 12, and holds the lead 13 by covering a portion of the first parallel portion 13A of the lead 13.

[0027] That is, in the semiconductor device 100, the lower surface 12L of the die pad 12, the end surface of the extension portion 12CE, and a portion of the first parallel portion 13A of the lead 13 are exposed from the sealing body 17, and the rest is sealed by the sealing body 17.

[0028] As described above, the semiconductor device 100 receives power from an external power source connected to a printed wiring board, for example, by electrically connecting the second parallel portion 13B of the lead 13 to the printed wiring board.

[0029] In the semiconductor device 100 mounted on the printed wiring board, the lower surface 12L of the die pad 12 is exposed from the sealing body 17, so that heat generated when the semiconductor chip 15 receives a supply of electricity and operates can be released to the outside via the lower surface 12L of the die pad 12. In other words, the semiconductor device 100 has a structure intended to release heat generated when the semiconductor chip 15 operates via the die pad 12.

[0030] For example, heat dissipation of the semiconductor device 100 may be achieved by joining the lower surface 12L of the die pad 12 to a heat dissipation structure such as a heat sink that dissipates heat to the outside of the device to which the semiconductor device 100 is attached via a thermally conductive material such as metal.

[0031] [Prevention of flash burr formation on the underside of the die pad] 1 and 4, a description will be given of suppression of flash burr formation on the lower surface 12L of the die pad 12 during the manufacture of the semiconductor device 100. Fig. 4 is a cross-sectional view of the semiconductor device 100 taken along line 2-2 in Fig. 1, illustrating the state when molding resin 17M is injected to form the sealing body 17 during the manufacture of the semiconductor device 100.

[0032] As shown in Figure 4, the die pad 12 and leads 13 on which the semiconductor chip 15 is mounted are held by a mold 21 consisting of a lower mold 21A and an upper mold 21B, and mold resin 17M, which is the sealing body 17 before hardening, is injected into them.

[0033] Specifically, the lead frame 11 is fixed in such a manner that the die pad 12 on which the semiconductor chip 15 is mounted is placed on the lower mold 21A, and each of the leads 13 is sandwiched between the upper mold 21B and the lower mold 21A. That is, within the mold 21, the lower surface 12L and the extension portion 12CE of the die pad 12 are in contact with the upper surface of the lower mold 21A.

[0034] Then, molding resin 17M is injected from injection port 21O into sealing space Sp formed by lower mold 21A and upper mold 21B, and is cured to form sealing body 17. Thereafter, mold 21 is removed, and semiconductor device 100 is manufactured.

[0035] When the lead frame 11 is fixed in the mold 21, it is preferable to position the die pad 12 so that the extension 12CE faces the injection port 21O for the molding resin 17M. This causes one end of the support bar SB, the other end of which is connected to the extension 12CE, to face the injection port 21O. When the molding resin 17M is injected through the injection port 21O, the support bar SB acts as a guide to guide the molding resin 17M into the sealing space Sp.

[0036] The specific mechanism for suppressing the formation of flash burrs will be described below. The molding resin 17M is supplied into the sealing space Sp from the injection port 21O at a predetermined pressure. Most of the molding resin 17M supplied into the sealing space Sp flows along the support bar SB and reaches the extension portion 12CE of the die pad 12, as shown by the solid arrow in Figure 4, for example.

[0037] The molding resin 17M that has reached the extension 12CE flows through the upper surface of the protrusion 12C at the portion where the extension 12CE of the protrusion 12C is formed, into the space below the protrusion 12C, in other words, the space between the protrusion 12C and the lower mold 21A, or in other words, the space surrounded by the protrusion 12C including the extension 12CE (see FIG. 4).Then, the molding resin 17M flows from the lower right corner of the die pad 12 in FIG. 1 around to the upper left corner diagonally opposite the lower right corner.

[0038] That is, in the portion where extension 12CE of protrusion 12C is formed, molding resin 17M flows into the space below protrusion 12C while it is on protrusion 12C. Therefore, in the portion where extension 12CE of protrusion 12C is formed, molding resin 17M also comes to be on top of protrusion 12C at the same time that molding resin 17M flows into the space below protrusion 12C.

[0039] For example, if the extension portion 12CE is not formed on the protrusion 12C of the die pad 12, i.e., if the support bar SB is directly connected to the protrusion 12C, the molding resin 17M injected along the support bar SB will enter the space below the protrusion 12C after reaching the protrusion 12C.

[0040] The molding resin 17M that has entered the space below the protrusion 12C in this way has almost no escape route to the space above the protrusion 12C, and therefore its momentum may be concentrated on the lower end side of the die pad 12. In other words, pressure is applied to the lower end of the die pad 12 by the molding resin 17M.

[0041] If pressure is applied to the lower end of the die pad 12, resin may seep in from the lower end between the lower surface 12L of the die pad 12 and the lower mold 21A, causing the die pad 12 to lift up and the lower surface 12L to separate from the lower mold 21A. Also, there is a risk that the molding resin 17M that has seeped in under the protruding portion 12C of the die pad 12 may generate a force that presses the protruding portion 12C upward, causing the die pad 12 to lift up.

[0042] For example, if the molding resin 17M gets into the gap between the lower surface 12L of the die pad 12 and the lower mold 21A, the molding resin 17M may harden in this state, which may cause flash burrs to form on the lower surface 12L of the die pad 12.

[0043] If flash burrs are formed on the lower surface 12L of the die pad 12, the heat dissipation performance of the lower surface 12L of the die pad 12 will be reduced when the semiconductor chip 15 is driven, which may eventually lead to a rise in temperature of the semiconductor chip 15 and a malfunction. Also, for example, if a large number of flash burrs remain on the lower surface 12L of the die pad 12, the effort required to remove the flash burrs in order to ensure heat dissipation will increase.

[0044] In manufacturing the semiconductor device 100 of this embodiment, the die pad 12 is positioned so that the extension 12CE faces the injection port 21O for the molding resin 17M, in other words, so that the extension 12CE faces the injection port 21O. As a result, the molding resin 17M that flows down the support bar SB first reaches the extension 12CE and then flows to other parts. In other words, the molding resin 17M injected from the injection port 21O first reaches the extension 12CE before reaching the underside of the protrusion 12C.

[0045] Therefore, in the manufacture of the semiconductor device 100 of this embodiment, the pressure of the molding resin 17M is weakened once the molding resin 17M reaches the extension portion 12CE, thereby weakening the pressure applied to the lower end of the die pad 12 when the molding resin 17M subsequently reaches the underside of the convex portion 12C.

[0046] Furthermore, during the manufacturing of semiconductor device 100 of this embodiment, as described above, molding resin 17M also comes to be placed on top of protrusion 12C at the same time that molding resin 17M flows into the space below protrusion 12C, so that pressure from molding resin 17M is applied to extension 12CE in the downward direction in FIG.

[0047] As a result, a pressing force acts from above on the entire die pad 12, so that even if the molding resin 17M reaches the lower end of the die pad 12 after reaching the extension portion 12CE, the molding resin 17M is less likely to enter between the lower surface 12L of the die pad 12 and the lower mold 21A.

[0048] Therefore, according to the semiconductor device 100 of this embodiment, an extension portion 12CE is formed at the tip of the protrusion 12C of the die pad 12, which reduces the pressure when the molding resin 17M is injected during the manufacture of the semiconductor device 100 and also provides the effect of the molding resin 17M pressing down on the die pad 12.

[0049] Therefore, according to the semiconductor device 100 of this embodiment, in a configuration in which the lower surface 12L of the die pad 12 is exposed from the sealing body 17 as sealing resin, it is possible to suppress the formation of flash burrs on the lower surface 12L of the die pad 12.

[0050] In the semiconductor device 100 of this embodiment, the extension 12CE is formed continuously from the protrusion 12C of the die pad 12, but this is not limiting and the extension 12CE may be formed as a separate body. For example, after the protrusion 12C is formed on the die pad 12, the extension 12CE may be formed at the tip of the protrusion 12C using an adhesive or the like.

[0051] In the semiconductor device 100 of this embodiment, the extension 12CE is on the same plane as the lower surface 12L of the die pad 12, but this is not limiting. For example, the extension 12CE may be configured so that its thickness in the height direction is slightly smaller than the thickness of the die pad 12 including the thickness of the region where the semiconductor chip 15 is mounted.

[0052] This prevents the lower surface 12L of the die pad 12 from floating above the lower mold 21A, for example, when the die pad 12 is placed in the mold 21 because the extension 12CE becomes thicker due to slight dimensional tolerances, etc. In other words, by making the thickness of the extension 12CE slightly smaller in advance, downward pressure from the molding resin 17M can be reliably applied to the extension 12CE.

[0053] In the semiconductor device 100 of this embodiment, the die pad 12 has a support bar SB at each of its four corners, but this is not limiting and it is not necessary to provide a support bar SB at every corner. For example, it may be possible to provide only the support bar SB closest to the injection port 21O used as a guide for injecting the molding resin 17M.

[0054] [Variation 1] Modification 1 of the semiconductor device 100 according to the first embodiment will be described below with reference to Fig. 5. Fig. 5 is a top view of the semiconductor device 110 according to modification 1. The semiconductor device 110 is different from Example 1 in the formation mode of the extension portion 12CE, but is otherwise similar to Example 1.

[0055] In semiconductor device 110 of this modified example, two extensions 12CE are formed to sandwich the lower right corner of protrusion 12C in the figure. That is, in semiconductor device 110 of this modified example, support bar SB is directly connected to the corner of protrusion 12C, and two extensions 12CE are formed to sandwich support bar SB.

[0056] Even when the extension portion 12CE is formed in this manner, when the molding resin 17M is injected, most of the molding resin 17M supplied from the injection port 21O along the support bar SB passes through the upper surface of each of the extension portions 12CE before entering the space.

[0057] Therefore, according to the semiconductor device 110 of this modification, similarly to the first embodiment, it is possible to release the pressure of the molding resin 17M at the time of injection and obtain the effect of pressing down the die pad 12 by the molding resin 17M.

[0058] Therefore, according to the semiconductor device 110 of this modification, in a configuration in which the lower surface 12L of the die pad 12 is exposed from the sealing body 17, it is possible to prevent flash burrs from being formed on the lower surface 12L of the die pad 12.

[0059] [Variation 2] A second modification of the semiconductor device 100 according to the first embodiment will be described below with reference to Fig. 6. Fig. 6 is a top view of a semiconductor device 120 according to the second modification. The semiconductor device 120 differs from the first embodiment and the first modification in the manner in which the extension portion 12CE is formed, but is otherwise similar to the first embodiment and the first modification.

[0060] In the semiconductor device 120 of this modified example, one extension portion 12CE is formed at the center of each side of the die pad 12. That is, in the semiconductor device 120 of this modified example, two extension portions 12CE are formed to face each other in the up-down direction and the left-right direction in the drawing.

[0061] Even when the extension portion 12CE is formed in this manner, the pressure of the molding resin 17M at the time of injection can be released, and the molding resin 17M can have the effect of pressing down the die pad 12.

[0062] Specifically, in the semiconductor device 120 of this modified example, one extension portion 12CE is formed at the center of each side of the die pad 12, so that when the molding resin 17M reaches the upper surface 12U of the die pad 12 along the support bar SB, for example, and spreads over the upper surface 12U, the molding resin 17M reaches each of the extension portions 12CE.

[0063] Therefore, in the semiconductor device 120 of this modification, pressure from the molding resin 17M can be applied downward in a balanced manner across the entire die pad 12, compared to when the extension 12CE is formed only at one corner of the protrusion 12C.

[0064] Therefore, according to the semiconductor device 120 of this modified example, similar to Example 1, in a configuration 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 flash burrs on the lower surface 12L of the die pad 12.

[0065] The manner in which the extensions 12CE are formed in the above-described first embodiment, first modification, and second modification is merely an example, and the number and positions of the extensions 12CE may be changed as appropriate. For example, in the first embodiment and the first modification, the extensions 12CE are formed only in the lower right corner in the drawing, but this is not limiting, and the extensions 12CE may also be formed in the upper left corner diagonally in the drawing. [Explanation of symbols]

[0066] 100, 110, 120 Semiconductor device 11 Lead frame 12 die pad 12C convex part 12CE extension 13 Lead 15 Semiconductor chips 17 Sealing body 21 Mold

Claims

1. a lead frame including a flat die pad and leads, the flat die pad having a mounting area on one main surface for mounting a semiconductor chip, the flat die pad protruding laterally along the one main surface in an eave-like shape and having frame-shaped protrusions on the sides in a top view; a semiconductor chip mounted in the mounting area; an encapsulant that covers the side surface of the die pad while exposing the other main surface of the die pad, encapsulates the semiconductor chip on the one main surface of the die pad, holds the die pad, and holds the leads; The semiconductor device is characterized in that the protrusion has an extension portion that is partially provided at the tip of the protrusion and extends downward from the tip.

2. the die pad has a rectangular top surface shape, 2. The semiconductor device according to claim 1, wherein the extension is formed at least at one corner of the die pad when viewed from above.

3. 3. The semiconductor device according to claim 2, further comprising a plurality of plate-like members each having a plate shape and extending outward from the tip of each of the protrusions at the corners of the die pad.

4. 3. The semiconductor device according to claim 2, wherein the extensions are formed in two such that the one corner is sandwiched between the extensions when viewed from above.

5. the die pad has a rectangular top surface shape, 2. The semiconductor device according to claim 1, wherein the extensions are formed at the center of each side of the die pad when viewed from above.

6. 6. The semiconductor device according to claim 1, wherein the tip of the extension is exposed from the sealing body.

7. 2. The method for manufacturing a semiconductor device according to claim 1, a sealing material injection step of placing the lead frame on which the semiconductor chip is mounted in a mold and injecting the sealing material into the mold, A method for manufacturing a semiconductor device, characterized in that in the encapsulant injection step, the lead frame is positioned so that the extension portion of the die pad faces the encapsulant injection port provided in the mold.

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