Semiconductor device

Abstract

To provide a semiconductor device which minimizes exposure of a substrate, suppresses intrusion of moisture from outside, and is excellent in reliability.SOLUTION: A semiconductor device 200 includes a semiconductor chip 10, a substrate 20 where the semiconductor chip is mounted on a first main surface side, and a sealing resin 30 covering the substrate in a part where the semiconductor chip is mounted, wherein on a second main surface side opposite to the mounted surface of the semiconductor chip, the semiconductor device has a plurality of hole parts 60 penetrating to the second main surface of the substrate in the sealing resin, a heat conductive member 40 is coated onto the rear face side of the sealing resin 30 so as to fill the heat conductive member 40 into a hole part 60, and a coating surface of the heat conductive member is stuck to a heat dissipation member 50.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a semiconductor device. [Background technology]

[0002] In recent years, semiconductor devices with resin-sealed packaging structures such as QFP (Quad Flat Package) have been experiencing increased heat generation from semiconductor chips due to the high integration and high speed of LSIs. Heat generated by semiconductor chips adversely affects the lifespan of the device and the package, reducing reliability and even destroying the device. Furthermore, it is difficult to avoid the increase in heat generation from semiconductor chips when increasing capacity and miniaturizing products through the creation of a series of products. For this reason, improving the heat dissipation performance of semiconductor chips has become an important issue for packaged semiconductors. As one of such measures to improve heat dissipation, a structure has been proposed in which a metal heat sink is bonded to a semiconductor device in a package structure (see, for example, Patent Document 1 and Patent Document 2). In this semiconductor device, a heat sink is bonded to the back surface of a substrate on which a semiconductor chip is mounted. The back surface of the heat sink is then exposed to the bottom surface of the package body. With this structure, heat from the semiconductor device is released to the outside of the package through the heat sink. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 06-097323 [Patent Document 2] International Publication No. 2016 / 092938 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technologies described in Patent Documents 1 and 2, a large area is formed on the back side of the substrate on which the semiconductor chip is mounted, which is not sealed with resin, in order to bond a heat sink. This raises concerns about warping of the package structure due to uneven stress caused by differences in the amount of sealing resin on both sides of the substrate, and adverse effects on the semiconductor chip due to moisture entering from outside into the unsealed area. As a result, semiconductor devices with conventional package structures are unable to achieve sufficient heat dissipation, making it difficult to ensure reliability.

[0005] In order to solve the above-mentioned problems, the present invention provides a semiconductor device with excellent reliability.

[0006] The above and other objects of the present invention and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0007] The semiconductor device of the present invention includes a semiconductor chip, a substrate having the semiconductor chip mounted on a first main surface thereof, and a sealing resin covering the portion of the substrate having the semiconductor chip mounted thereon, and the sealing resin has a plurality of holes on a second main surface thereof opposite the surface on which the semiconductor chip is mounted, the holes penetrating the second main surface of the substrate. [Effects of the Invention]

[0008] According to the present invention, a semiconductor device with excellent reliability can be provided.

[0009] Problems, configurations, and effects other than those described above will become clear from the following description of the embodiments. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a configuration of a conventional semiconductor device. [Figure 2] 1 is a diagram illustrating a configuration of a semiconductor device according to an embodiment of the present invention. [Figure 3]3 is an enlarged view of the semiconductor chip and the heat conduction member of the semiconductor device shown in FIG. 2 and their surroundings. [Figure 4] 1A and 1B are diagrams showing the configuration of a sealing resin on the back surface side of a substrate of a semiconductor device; [Figure 5] 10A and 10B are diagrams showing the configuration of a sealing resin on the back surface side of a substrate of a semiconductor device according to a modified example; [Figure 6] 10A and 10B are diagrams showing the configuration of a sealing resin on the back surface side of a substrate of a semiconductor device according to a modified example; [Figure 7] 10A and 10B are diagrams showing the configuration of a sealing resin on the back surface side of a substrate of a semiconductor device according to a modified example; DETAILED DESCRIPTION OF THE INVENTION

[0011] An example of a semiconductor device according to an embodiment of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following example. In each of the drawings described below, common components are given the same reference numerals. Furthermore, in the drawings used in this specification, identical or corresponding components are given the same reference numerals, and repeated description of these components may be omitted. The explanation will be given in the following order. 1. Overview of conventional semiconductor device 2. Embodiments of the semiconductor device 3. Modifications of semiconductor devices

[0012] 1. Overview of semiconductor device with conventional configuration [Configuration of conventional semiconductor device] Before describing the configuration of the semiconductor device of the present invention, the configuration of a conventional semiconductor device and the problems that arise from it will be described. Fig. 1 shows the configuration of a conventional semiconductor device.

[0013] Fig. 1 is a side view showing the mounting structure of a semiconductor device 100 having a package structure. The semiconductor device 100 shown in Fig. 1 includes a semiconductor chip 10, a substrate 20, a sealing resin 30, a heat conductive member 40, and a heat dissipation member 50. The semiconductor chip 10 is mounted on the front surface of the substrate 20. The sealing resin 30 is formed in a shape that covers the semiconductor chip 10 and the area of the substrate 20 on which the semiconductor chip 10 is mounted. In addition, in the semiconductor device 100 having a package structure, the sealing resin 30 is joined to the heat dissipation member 50 by the heat conductive member 40 formed on the entire surface of the sealing resin 30 on the back surface side.

[0014] The semiconductor device 100 has a package structure in which a part of the substrate 20 and the semiconductor chip 10 are sealed with sealing resin 30 to protect the semiconductor chip 10 from moisture, dust, etc. Heat generated in the semiconductor chip 10 passes through the sealing resin 30 and the heat conduction member 40 and is released to the outside from the heat dissipation member 50. In the semiconductor device 100 having such a package structure, the sealing resin 30 is required to have a certain thickness in order to protect the semiconductor chip 10 from external degradation factors and to ensure the pressure resistance of the semiconductor device 100. For this reason, in the semiconductor device 100 having a package structure, a certain thickness of sealing resin 30 is interposed between the semiconductor chip 10, which generates heat, and the heat conduction member 40 and heat dissipation member 50, which dissipate the heat.

[0015] As a result, in the semiconductor device 100, heat generated in the semiconductor chip 10 is difficult to transfer to the thermal conductive member 40 and the heat dissipation member 50, and is likely to accumulate in the sealing resin 30. Heat accumulation in the sealing resin 30 adversely affects the lifespan of the semiconductor chip 10 and reduces reliability. Furthermore, when attempting to increase the capacity and reduce the size of the semiconductor device 100 as a product, it is difficult to avoid an increase in the amount of heat generated by the semiconductor chip 10. For this reason, a configuration that improves the heat dissipation properties of the heat generated in the semiconductor chip 10 is needed.

[0016] 2. Embodiments of the Semiconductor Device [Configuration of semiconductor device] Next, the configuration of the semiconductor device of this embodiment will be described. The configuration of the semiconductor device of this embodiment is shown in Figures 2 and 3. Figure 2 is a side view showing the mounting structure of a semiconductor device 200 having a package structure. Figure 3 is an enlarged view of the periphery of the semiconductor chip 10 and heat conduction member 40 of the semiconductor device 200 shown in Figure 2.

[0017] 2 includes a semiconductor chip 10, a substrate 20, a sealing resin 30, a heat conduction member 40, and a heat dissipation member 50. The semiconductor chip 10 is mounted on the surface of the substrate 20. The sealing resin 30 is formed in a shape that covers the semiconductor chip 10 and the region of the substrate 20 where the semiconductor chip 10 is mounted. In addition, in the semiconductor device 200 having a package structure, the sealing resin 30 is joined to the heat dissipation member 50 by the heat conduction member 40 formed on the entire surface of the sealing resin 30 on the back surface side.

[0018] The semiconductor chip 10 is a general semiconductor element, and may be a power semiconductor chip, etc. The semiconductor chip 10 has external electrodes for mounting on the substrate 20, and is mounted on the first main surface side of the substrate 20. The substrate 20 is, for example, a substrate or lead frame on which the semiconductor chip 10 can be mounted. The semiconductor chip 10 is mounted on a die pad of the substrate 20, and external electrodes of the semiconductor chip 10 are connected to wiring that constitutes the substrate 20. In addition, the substrate 20 has external terminals 21 for external connection that extend outside the sealing resin 30. These extended external terminals 21 are not sealed by the sealing resin 30.

[0019] The sealing resin 30 is formed in a shape that covers the semiconductor chip 10, part of the substrate 20, and part of the heat dissipation member 50. The entire semiconductor chip 10 is covered with the sealing resin 30. The substrate 20 is covered so as to include the area where the semiconductor chip 10 is mounted. The heat dissipation member 50 is covered so that the back surface of the heat dissipation member 50 is exposed to the outside from the sealing resin 30.

[0020] The heat dissipation member 50 is a plate-shaped member with high thermal conductivity, and is made of, for example, Cu, Al, or the like. A heat conduction member 40 is filled between the sealing resin 30 and the heat dissipation member 50. The sealing resin 30 and the heat dissipation member 50 are not in direct contact with each other but are connected by the heat conduction member 40. The heat conduction member 40 is made of a silicone gel mixed with highly thermally conductive metal powder such as Cu or Al. However, the heat conduction member 40 is not limited to a silicone gel mixed with metal powder as long as it is a liquid or gel-like substance with good thermal conductivity and low moisture absorption.

[0021] The semiconductor device 200 also has holes 60 in the sealing resin 30 on the second main surface side of the substrate 20. As shown in FIG. 3 , the holes 60 penetrate the sealing resin 30 from the heat dissipation member 50 side to the second main surface of the substrate 20. Furthermore, the holes 60 are filled with thermally conductive members 40. The thermally conductive members 40 are formed continuously from the entire surface between the contact surfaces of the heat dissipation member 50 and the sealing resin 30 to the inside of the holes 60. Therefore, the heat dissipation member 50 is connected to the second main surface side of the substrate 20 via the thermally conductive members 40 filled in the holes 60.

[0022] By filling the holes 60 with the heat conduction member 40, which has a higher thermal conductivity than the sealing resin 30, the heat generated in the semiconductor chip 10 moves directly from the substrate 20 to the heat conduction member 40 without passing through the sealing resin 30. Then, by moving the heat from the heat conduction member 40 to the heat dissipation member 50, it is possible to improve the heat dissipation performance of the semiconductor device 200.

[0023] 4 shows the configuration of the sealing resin 30 on the back surface side of the substrate 20 in the semiconductor device 200. In FIG. 4, only the sealing resin 30, the hole 60 formed in the sealing resin 30, and the external terminals 21 extending outside the sealing resin 30 are shown.

[0024] 4, the holes 60 are distributed over the entire surface of the sealing resin 30 on the back surface side of the substrate 20. In the semiconductor device 200, the holes 60 have a circular cross section in the surface direction of the substrate 20. In the semiconductor device 200, the discontinuous holes 60 are evenly arranged on the second main surface side of the substrate 20. This distributes stress caused by the curing shrinkage of the sealing resin 30 and suppresses warping of the semiconductor device 200. Furthermore, by providing a plurality of holes 60 on the second main surface side of the substrate 20, a sufficient total contact area between the substrate 20 and the heat conductive member 40 is ensured. This improves the adhesion between the substrate 20 and the heat conductive member 40 and the heat dissipation member 50, thereby improving the heat dissipation performance of the semiconductor device 200. Therefore, the above configuration improves the reliability of the semiconductor device 200.

[0025] From the viewpoint of heat dissipation, it is preferable that the total area of the holes 60 (cross-sectional area in the surface direction of the substrate 20) is large. However, if the area where the holes 60 are formed is large, the difference in the amount of sealing resin 30 between the first main surface side and the second main surface side of the substrate 20 becomes large. In this case, the difference in stress of the sealing resin 30 between the first main surface side and the second main surface side becomes large, and warping of the semiconductor device 200 is likely to occur. For this reason, for example, it is preferable that the total area of the holes 60 is 50% or more and 70% or less of the total contact area between the sealing resin 30 and the heat dissipation member 50.

[0026] Furthermore, in consideration of the adhesiveness between the sealing resin 30 and the substrate 20, it is preferable to ensure that the intervals between the holes 60 are 0.5 mm or more. The diameter of each hole 60 needs to be adjusted according to the thickness of the sealing resin 30 formed on the back surface of the substrate 20. In order to fill the holes 60 with the thermal conductive member 40, the thicker the sealing resin 30, the larger the diameter of the hole 60 needs to be. For example, it is preferable that the diameter of the hole 60 is approximately the same as the thickness of the sealing resin 30 formed on the back surface of the substrate 20. The thickness of the sealing resin 30 formed on the back surface of the substrate 20 is preferably about 0.7 to 1.0 mm, taking into consideration the size of the semiconductor device 100, the adhesion between the substrate 20 and the sealing resin 30, heat dissipation, etc. Therefore, the diameter of the hole 60 is preferably 0.7 mm or more and 1.0 mm or less. By forming a plurality of holes 60 with this diameter, the holes 60 are formed so that the ratio of the contact area between the sealing resin 30 and the heat dissipation member 50 to the entire area is equal to the above-mentioned ratio. 4, it is preferable that the holes 60 are evenly arranged. For example, it is preferable that the difference in area between the individual holes 60 is 10% or less. It is also preferable that the difference in the spacing between adjacent holes 60 in one direction is 10% or less.

[0027] The semiconductor device 200 is fabricated, for example, as follows. First, the semiconductor chip 10 is mounted on the die pad of the substrate 20. The substrate 20 with the semiconductor chip 10 mounted thereon is placed in a mold. The mold has a pattern of holes 60 formed on the bottom. With the substrate 20 placed on this bottom pattern, an insulating resin that will become the sealing resin 30 is poured into the mold. Then, after the resin is cured, the semiconductor chip 10 and substrate 20 sealed with the sealing resin 30 having the multiple holes 60 are removed from the mold. This forms a semiconductor device 200 consisting of the semiconductor chip 10, the substrate 20, and the sealing resin 30 in which the hole 60 is formed. After this step, a protective film or the like may be attached to the back side of the sealing resin 30 to protect the hole 60.

[0028] Next, the semiconductor device 200, which is made up of the semiconductor chip 10, the substrate 20, and the sealing resin 30 in which the hole 60 is formed, is moved to the location where it will be used. Then, at the location where it will be used, the protective film or the like is peeled off, and the thermal conductive member 40 is applied to the back side of the sealing resin 30. The thermal conductive member 40 is applied so as to fill the hole 60. Then, the applied surface of the thermal conductive member 40 is attached to the heat dissipation member 50. Through the above steps, the semiconductor device 200 having the configuration shown in FIG. 2 can be fabricated.

[0029] As described above, when the semiconductor device 200 is used by a user, the thermal conductive member 40 is applied and bonded to the heat dissipation member 50. Therefore, the semiconductor device 200 has the above-described effects even when it is composed of the semiconductor chip 10, the substrate 20, and the sealing resin 30 having the holes 60 formed therein. That is, by distributing the holes 60 in the sealing resin 30 to multiple locations, the semiconductor device 200 can mitigate stress differences caused by the curing shrinkage of the sealing resin 30 on both sides of the substrate 20 and suppress warping of the package structure due to uneven stress. Furthermore, by distributing the holes 60 in the sealing resin 30 to multiple locations, the exposed area of the substrate 20 can be minimized, which suppresses the intrusion of moisture from the outside and ensures higher reliability.

[0030] 3. Modified Examples of Semiconductor Devices Next, modified examples of the semiconductor device of this embodiment will be described. The configuration of the modified example of the semiconductor device will be described with reference to Figures 5 to 7. Note that in this modified example, only the shape of the hole 60 formed in the sealing resin 30 differs from that of the semiconductor device of the above-described embodiment. For this reason, Figures 5 to 7 only show the configuration of the sealing resin 30 on the back surface side of the substrate 20 in the semiconductor device 200, which corresponds to the configuration shown in Figure 4 above.

[0031] In the semiconductor device 200 shown in FIG. 5 , holes 61 are distributed over the entire surface of the sealing resin 30 on the back side of the substrate 20. The holes 61 shown in FIG. 5 are groove-shaped holes 61 formed continuously in one direction in the sealing resin 30. Some of the holes 61 are formed continuously from one end to the other end. Therefore, some of the holes 61 are exposed from the side of the sealing resin 30. By forming the holes 61 in a groove-like form continuous in one direction, air bubbles inside the heat conduction member 40 are expelled to the outside of the holes 61 when the heat conduction member 40 is filled. Air bubbles inside the holes 61 after filling with the heat conduction member 40 inhibit heat transfer from the substrate 20 to the heat dissipation member 50. Furthermore, the presence of air bubbles in the heat conduction member 40 reduces the adhesion between the sealing resin 30 and the heat dissipation member 50. 5, the adhesion between the sealing resin 30 and the heat dissipation member 50 is improved, and the heat dissipation performance is further improved. As a result, the reliability of the semiconductor device 200 is improved. The hole 61 is preferably formed, for example, so that its width is in the same range as the diameter of the hole 60 shown in Fig. 4. The ratio of the total area of the hole 61 to the total contact area between the sealing resin 30 and the heat dissipation member 50 can also be in the same range as the hole 60 shown in Fig. 4.

[0032] 6 and 7, the semiconductor device 200 may be configured such that holes 62, 63 are provided in a partial region on the back surface of the substrate 20. In the semiconductor device 200, heat generated by the semiconductor chip 10 mounted on the substrate 20 is dissipated to the outside through the heat dissipation member 50. For this reason, a configuration that enhances heat dissipation is required in the portion of the substrate 20 on which the semiconductor chip 10 is mounted. For this reason, in the semiconductor device 200, the above-mentioned holes 62, 63 and the heat conduction member 40 must be disposed at least in the position where the semiconductor chip 10 is mounted.

[0033] Therefore, the semiconductor device 200 has holes 62, 63 in the sealing resin 30 at least on the back surface side of the substrate 20 in the region where the semiconductor chip 10 is mounted or on the back surface side of the substrate 20 in the region of the die pad on which the semiconductor chip 10 is mounted. In Fig. 6, holes 62 having a circular cross section in the surface direction of the substrate 20 are formed discontinuously and evenly in the sealing resin 30 on the back surface side of the substrate 20 in the region where the semiconductor chip 10 is mounted. In Fig. 7, groove-shaped holes 63 formed continuously in one direction in the sealing resin 30 are evenly arranged on the back surface side of the substrate 20 in the region where the semiconductor chip 10 is mounted.

[0034] Even in a configuration in which the holes 60 are formed only on the back side of the region where the semiconductor chip 10 or the die pad is formed, it is preferable that the size of each of the holes 62, 63 be within the above-mentioned range. It is also preferable that the total area of the holes 62, 63 be within the above-mentioned range with respect to the region where the semiconductor chip 10 or the die pad is formed.

[0035] In a configuration in which the holes 60 are provided only in the area of the semiconductor chip 10, the exposed area of the substrate 20 can be minimized. Therefore, the semiconductor device 200 configured as described above can suppress the intrusion of moisture from the outside and ensure higher reliability. Furthermore, since the holes 60 are formed in the area of the semiconductor chip 10, heat dissipation can also be ensured.

[0036] In the above-described embodiment, the hole shape is circular or linear, but the shape of the hole is not particularly limited. For example, the hole may be a polygonal shape other than a circle, a geometric pattern, or a curved shape other than a straight line.

[0037] It should be noted that the present invention is not limited to the above-described embodiments and various modifications are possible. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to an embodiment including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to delete part of the configuration of each embodiment, or to add or replace other configurations. [Explanation of symbols]

[0038] 10 semiconductor chip, 20 substrate, 21 external terminal, 30 sealing resin, 40 thermal conductive member, 50 heat dissipation member, 60, 61, 62, 63 hole portion, 100, 200 semiconductor device

Claims

1. A semiconductor chip; a substrate having the semiconductor chip mounted on a first main surface side; a sealing resin that covers the substrate at a portion on which the semiconductor chip is mounted, The sealing resin has a plurality of holes penetrating to the second main surface of the substrate on the side of a second main surface opposite to the mounting surface of the semiconductor chip. Semiconductor device.

2. The heat conductive member is filled in the plurality of holes. The semiconductor device according to claim 1 .

3. a heat dissipation member bonded to the substrate and the sealing resin via the heat conduction member; The semiconductor device according to claim 2 .

4. The sealing resin has the hole at least on the second main surface side of the substrate in the region where the semiconductor chip is mounted. The semiconductor device according to claim 1 .

5. The sealing resin has a hole having a circular cross section in a surface direction of the substrate. The semiconductor device according to claim 1 .

6. The sealing resin has the groove-shaped hole portion formed continuously in one direction. The semiconductor device according to claim 1 .

7. The hole has a groove shape that is continuous from one end of the sealing resin to the other end. The semiconductor device according to claim 6.

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