Semiconductor device

Abstract

To suppress leakage of a sealing member to the outside in a semiconductor device having a through hole in a lid part of a case.SOLUTION: The semiconductor device 1 includes a substrate 20 on which a semiconductor chip 10 is mounted, a heat sink 30 having a front surface on which the substrate 20 is disposed, a case 40 including a sidewall portion 41 disposed on the front surface of the heat sink 30 so as to surround the heat sink 30 and a housing region 40a including the substrate 20, and a lid portion 42 disposed on the sidewall portion 41 so as to cover the housing region 40a, and a sealing member 35 filling the housing region 40a and sealing the substrate 20. The lid portion 42 includes a through hole 42a, and protrusions (grooves) 43a to 43e which surround the through hole 42a over a plurality of rounds in a plan view and are provided on an inner surface of the lid portion 42 without being in contact with the sealing member 35.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In order to prevent leakage of the sealing material from terminal holes in the lid or from the gap between the case and the lid, some semiconductor devices have protrusions on the inner surface of the lid that come into contact with the sealing material and intentionally cause it to creep up (see, for example, Patent Documents 1 and 2).In addition, there are semiconductor devices in which protrusions are provided on the inner wall of the case to prevent leakage of the sealing material, and semiconductor devices in which the upper surface of a protrusion for holding the terminals on the inner wall of the case is separated from the lower surface of the lid to prevent the sealing material from creeping up onto the lid (see, for example, Patent Documents 3 and 4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-42658 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-297979 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-59715 [Patent Document 4] Japanese Patent Application Laid-Open No. 2011-243798 Summary of the Invention [Problem to be solved by the invention]

[0004] In a semiconductor device having a through hole in the lid of the case, conventional techniques have not been able to sufficiently prevent the sealing member from leaking to the outside through the through hole.

[0005] An object of the present embodiment is to prevent leakage of a sealing material to the outside in a semiconductor device having a through hole in the lid of the case. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a semiconductor device comprising: a substrate on which a semiconductor chip is mounted; a heat sink having the substrate arranged on its front surface; a side wall portion arranged on the front surface of the heat sink so as to surround a storage area including the substrate together with the heat sink; and a lid portion arranged on the side wall portion and covering the storage area; and a sealing member filled in the storage area and sealing the substrate, wherein the lid portion has a through hole and a protrusion or groove portion that surrounds the through hole in a plan view over multiple peripheries and is provided on the inner surface of the lid portion without coming into contact with the sealing member.

[0007] The protrusion or the groove may include a portion that extends in a direction perpendicular to the direction in which the liquid material contained in the sealing member creeps up.

[0008] The sealing member may be a silicone gel containing a liquid low-molecular-weight siloxane.

[0009] The protrusion or the groove may be provided so as to surround the through hole in a ring shape over multiple circumferences in a plan view.

[0010] The protrusion or the groove may be provided so as to surround the through hole in a spiral shape over multiple circumferences in a plan view.

[0011] The height of the protrusions may be 2 mm or less, the width may be 0.5 mm or more and 1.5 mm or less, and the spacing between adjacent protrusions in the inner or outer circumferential direction may be 0.5 mm or more and 1.5 mm or less.

[0012] The groove may have a depth of 1 mm or less, a width of 0.5 mm to 1.5 mm, and an interval between adjacent grooves in the inner or outer circumferential direction of 0.5 mm to 1.5 mm.

[0013] The inner end may be bonded to the substrate, and the outer end may include an external connection terminal extending outward from the through hole.

[0014] The heat sink is rectangular, and the protrusions or grooves are provided in the long side direction of the heat sink in the same number as the number of circumferences, and the protrusions or grooves may also be provided in the short side direction of the heat sink in the same number as the number of circumferences.

[0015] The above summary of the invention does not list all of the necessary features of the present invention, and subcombinations of these features may also constitute inventions. [Effects of the Invention]

[0016] According to the disclosed technique, leakage of the sealing material to the outside can be suppressed in a semiconductor device having a through-hole in the lid of the case. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a side cross-sectional view of a semiconductor device according to a first embodiment. [Figure 2] 1 is a top view showing a part of a semiconductor device according to a first embodiment. [Figure 3] FIG. [Figure 4] 10A and 10B are diagrams illustrating creeping up of a sealing member in a semiconductor device of a reference example. [Figure 5] 5A to 5C are diagrams illustrating the creeping up of the sealing member in the semiconductor device according to the first embodiment. [Figure 6] 5A and 5B are diagrams illustrating examples of the arrangement positions of protrusions relative to the direction in which a liquid material contained in a sealing member rises in the semiconductor device of the first embodiment. [Figure 7] FIG. 10 is a perspective view showing how the liquid material spreads in the area where the protrusions are provided. [Figure 8] FIG. 10 is a side cross-sectional view of a semiconductor device according to a second embodiment. [Figure 9] FIG. 10 is a top view showing a part of a semiconductor device according to a second embodiment. [Figure 10] FIG. [Figure 11]10A and 10B are diagrams illustrating the rising of the sealing member in the semiconductor device according to the second embodiment. [Figure 12] FIG. 10 is a side cross-sectional view of a semiconductor device according to a first modified example. [Figure 13] FIG. 10 is a top view showing a part of a semiconductor device according to a second modified example. [Figure 14] FIG. 10 is a side cross-sectional view of a semiconductor device according to a third modified example. [Figure 15] FIG. 10 is a top view showing a part of a semiconductor device according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments will be described with reference to the drawings. In the following description, the terms "front surface" and "upper surface" refer to the XY plane facing upward (+Z direction) in the semiconductor device 1 of FIGS. 1 and 2. Similarly, "up" refers to the upward (+Z direction) direction in the semiconductor device 1 of FIGS. 1 and 2. The term "rear surface" refers to the XY plane facing downward (-Z direction) in the semiconductor device 1 of FIGS. 1 and 2. Similarly, the term "down" refers to the downward (-Z direction) direction in the semiconductor device 1 of FIGS. 1 and 2. Similar orientations will be used in other drawings as necessary. The terms "front surface," "upper surface," "upper," "rear surface," and "down" are merely convenient expressions for specifying relative positional relationships and do not limit the technical concept of the present invention. For example, "upper" and "down" do not necessarily refer to the vertical direction relative to the ground. In other words, the "upper" and "down" directions are not limited to the direction of gravity. In the following description, the term "main component" refers to a component containing, for example, 80 vol% or more.

[0019] [First embodiment] The semiconductor device of the first embodiment will be described with reference to FIGS. Fig. 1 is a side cross-sectional view of the semiconductor device of the first embodiment. Fig. 2 is a top view showing a part of the semiconductor device of the first embodiment. Fig. 1 is a cross-sectional view taken along dashed line II in Fig. 2. In Fig. 2, the positions of protrusions 43a to 43e formed on the inner surface of lid 42 are indicated by dashed lines.

[0020] As shown in FIG. 1, the semiconductor device 1 includes a substrate 20 on which a semiconductor chip 10 and external connection terminals 11 are mounted, a heat sink 30 on the front surface of which the substrate 20 is disposed, a sealing member 35, and a case 40.

[0021] The semiconductor chip 10 is mechanically and electrically (directly) connected to the substrate 20 by bonding wires 25. When there are multiple semiconductor chips 10, the bonding wires 25 may be used to electrically connect the multiple semiconductor chips 10 to each other. The semiconductor chip 10 includes a power device element made of, for example, silicon, silicon carbide, or gallium nitride. The thickness of the semiconductor chip 10 is, for example, 40 μm or more and 250 μm or less. The power device element is a switching element or a diode element.

[0022] The switching element is, for example, an IGBT (Insulated Gate Bipolar Transistor) or a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor). Such a semiconductor chip 10 has, for example, a drain electrode (or collector electrode) as a main electrode on the back surface, and a gate electrode and a source electrode (or emitter electrode) as a control electrode and a main electrode on the front surface, respectively.

[0023] The diode element is, for example, an FWD (Free Wheeling Diode) such as an SBD (Schottky Barrier Diode) or a PiN (P-intrinsic-N) diode. Such a semiconductor chip 10 has a cathode electrode as a main electrode on the back surface and an anode electrode as a main electrode on the front surface.

[0024] The semiconductor chip 10 includes at least one of a switching element and a diode element, as needed, and its back surface is directly bonded to a predetermined circuit pattern 22 on the substrate 20 by a bonding member 24. The bonding member 24 is solder or a metal sintered body. Lead-free solder is used as the solder. Lead-free solder mainly contains an alloy containing at least two of tin, silver, copper, zinc, antimony, indium, and bismuth. The solder may also contain additives. Examples of additives include nickel, germanium, cobalt, and silicon. The addition of additives to the solder improves its wettability, gloss, and bonding strength, thereby improving reliability. Examples of metals used in the metal sintered body include silver and silver alloys.

[0025] The semiconductor chip 10 may also use an RC (Reverse-Conducting)-IGBT that combines the functions of an IGBT and an FWD.

[0026] The external connection terminal 11 is electrically connected to any of the main electrodes or control electrodes of the semiconductor chip 10. An inner end (lower side in the figure) of the external connection terminal 11 is joined to the substrate 20, and an outer end (upper side in the figure) of the external connection terminal 11 extends outward from a through-hole 42a (described below) provided in the lid 42 of the case 40. A plurality of external connection terminals 11 may be mounted on the substrate 20. When the semiconductor device 1 is an inverter device, for example, four external connection terminals may be provided: a first input terminal to which a positive terminal of a DC power supply is connected, a second input terminal to which a negative terminal of the DC power supply is connected, a first output terminal, and a second output terminal.

[0027] The external connection terminal 11 has a cylindrical, prismatic, or plate-like shape. The external connection terminal 11 is made of a metal with excellent conductivity. Such metals include, for example, copper, aluminum, or an alloy containing at least one of these as a main component. The diameter of the external connection terminal 11 (the diagonal length in the case of a prismatic shape) is 0.5 mm or more and 2.5 mm or less. In the case of a plate-like shape, the thickness is 0.5 mm or more and 2.5 mm or less. The surface of the external connection terminal 11 may be plated. Examples of plating materials used in this case include nickel, nickel-phosphorus alloy, and nickel-boron alloy. The plated external connection terminal 11 has improved corrosion resistance. The inner end of the external connection terminal 11 is joined to the circuit pattern 22 of the substrate 20 by a joining member. The joining member is solder or a sintered metal. Lead-free solder is used as the solder. Lead-free solder is primarily composed of an alloy containing at least two of tin, silver, copper, zinc, antimony, indium, and bismuth. The solder may also contain additives, such as nickel, germanium, cobalt, or silicon. The addition of additives improves the solder's wettability, gloss, and bonding strength, thereby improving reliability. Examples of metals used in the metal sintered body include silver and silver alloys. The external connection terminals 11 may be joined to the circuit pattern 22 by ultrasonic bonding.

[0028] The substrate 20 includes an insulating plate 21, a circuit pattern 22, and a metal plate 23. The insulating plate 21 and the metal plate 23 are rectangular in plan view. The corners of the insulating plate 21 and the metal plate 23 may be chamfered. For example, the corners may be C-chamfered or R-chamfered. The size of the metal plate 23 is smaller than the size of the insulating plate 21 in plan view and is formed inside the insulating plate 21. The insulating plate 21 is made of a material that has insulating properties and excellent thermal conductivity. Such an insulating plate 21 is made of ceramics or insulating resin. Ceramics include aluminum oxide, aluminum nitride, and silicon nitride. The insulating resin is, for example, a paper phenol substrate, a paper epoxy substrate, a glass composite substrate, or a glass epoxy substrate. The thickness of the insulating plate 21 is 0.2 mm or more and 2.5 mm or less.

[0029] The circuit pattern 22 is formed on the front surface of the insulating plate 21. The circuit pattern 22 is made of a metal with excellent conductivity. Such a metal is, for example, copper, aluminum, or an alloy containing at least one of these as a main component. The thickness of the circuit pattern 22 is 0.1 mm or more and 2.0 mm or less. The surface of the circuit pattern 22 may be plated. Examples of plating materials used in this case include nickel, a nickel-phosphorus alloy, and a nickel-boron alloy. The plated circuit pattern 22 has improved corrosion resistance. The circuit pattern 22 is formed on the front surface of the insulating plate 21, for example, as follows: A metal plate is formed on the front surface of the insulating plate 21, and the metal plate is then subjected to etching or other processing to obtain the circuit pattern 22 with a predetermined shape. Alternatively, the circuit pattern 22 may be cut out from a metal plate and then pressure-bonded to the front surface of the insulating plate 21. Note that the circuit pattern 22 is merely an example. The number, shape, size, and position of the circuit patterns 22 may be appropriately selected as needed.

[0030] The metal plate 23 is formed on the rear surface of the insulating plate 21. The metal plate 23 has a rectangular shape. The area of ​​the metal plate 23 in a plan view is smaller than that of the insulating plate 21 and larger than the area of ​​the region where the circuit pattern 22 is formed. The corners of the metal plate 23 may be chamfered. For example, C-chamfering or R-chamfering may be used. The metal plate 23 is smaller than the insulating plate 21 and is formed on the entire surface of the insulating plate 21 except for the edges. The metal plate 23 is primarily composed of a metal with excellent thermal conductivity. The metal may be, for example, copper, aluminum, or an alloy containing at least one of these. The thickness of the metal plate 23 is 0.1 mm or more and 2.5 mm or less. The surface of the metal plate 23 may be plated. Examples of plating materials used in this case include nickel, a nickel-phosphorus alloy, and a nickel-boron alloy. The plated metal plate 23 has improved corrosion resistance. The metal plate 23 is formed on the rear surface of the insulating plate 21 as follows. A metal plate is formed on the rear surface of insulating plate 21, and then this metal plate is subjected to a process such as etching to obtain metal plate 23. Alternatively, metal plate 23 may be cut out from a metal plate in advance and pressure-attached to the front surface of insulating plate 21. The corners of metal plate 23 provided on the rear surface of insulating plate 21 in this manner may be R-chamfered or C-chamfered.

[0031] Examples of the substrate 20 having such a configuration include a DCB (Direct Copper Bonding) substrate, an AMB (Active Metal Brazed) substrate, and a resin insulating substrate. The substrate 20 may be attached to the front surface of the heat sink 30 via a bonding material such as solder. In addition to the semiconductor chip 10, other electronic components (e.g., a thermistor, a current sensor, etc.), a lead frame, etc. may be arranged on the substrate 20. Heat generated by the semiconductor chip 10 is conducted to the heat sink 30 via the circuit pattern 22, the insulating plate 21, and the metal plate 23, and is then dissipated. The semiconductor device 1 may have a plurality of substrates 20.

[0032] The sealing member 35 is filled in the storage area 40a including the substrate 20, and seals the substrate 20, etc. As shown in FIG. 1, the sealing member 35 is filled in the case 40 to a height that is sufficient to seal at least the semiconductor chip 10, the substrate 20, and the bonding wires 25.

[0033] Furthermore, the sealing member 35 is filled into the case 40 to a height that does not contact the inner surface (rear surface) of the lid portion 42. In other words, there is a gap between the inner surface (rear surface) of the lid portion 42 and the upper surface of the sealing member 35. This gap may be 5% or more and 100% or less of the filling height of the sealing member 35. Preferably, it is 10% or more and 50% or less. If this gap is too small, the sealing member 35 may push up the lid when thermally expanded, causing damage. If this gap is too large, the semiconductor device 1 becomes too thick to be accommodated in the specified space within the electrical equipment. Alternatively, the substrate 20, the semiconductor chip 10 mounted thereon, and the wires connecting them may not be sufficiently sealed, resulting in exposed areas and reduced insulation resistance.

[0034] The sealing member 35 is, for example, a silicone gel. The main material of the silicone gel is a polymeric siloxane entangled in a chain structure. The silicone gel contains a liquid low molecular weight siloxane. The liquid low molecular weight siloxane is contained in the silicone gel at, for example, 20 wt% or more and 30 wt% or less. The liquid low molecular weight siloxane does not entangle in a chain structure, but fills the gaps in the polymeric siloxane. The liquid low molecular weight siloxane functions as a buffer against thermal stress caused by temperature changes. Therefore, the liquid low molecular weight siloxane can maintain its insulating function against temperature changes in the sealing member 35.

[0035] The sealing member 35 is not limited to silicone gel. Other materials that are gel-like when filled into the storage area 40a may be used as the sealing member 35. The gel-like material may contain a liquid material (oil component) that seeps out from the sealing member 35 after hardening, as described below.

[0036] As shown in FIGS. 1 and 2, the case 40 includes a sidewall 41 and a lid 42. The sidewall 41 is disposed on the front surface of the heat sink 30, surrounding a storage area 40a including the substrate 20 together with the heat sink 30. The height of the sidewall 41 need only be sufficiently higher than the height of the stacked substrate 20 and semiconductor chip 10. In the example shown in FIG. 1, the sidewall 41 is attached to the front surface of the heat sink 30 along the periphery with an adhesive 26. The adhesive 26 is primarily composed of an organic adhesive. The organic adhesive has a heat resistance temperature of approximately 100°C to 200°C. Specifically, the adhesive is an epoxy, silicone, or acrylic adhesive. The adhesive may be in either a paste or sheet form.

[0037] The lid 42 is disposed on the side wall 41 and covers the storage area 40a. In the example of FIG. 1, the lid 42 is connected to the upper end of the side wall 41 and covers the storage area 40a. The lid 42 is also formed with a through hole 42a penetrating the lid 42 in the ±Z directions and protrusions 43a to 43e. In the examples of FIGS. 1 and 2, the through hole 42a is used as a terminal hole through which the outer end of the external connection terminal 11 is inserted. When used as a terminal hole, the through hole 42a only needs to allow the external connection terminal 11 to be inserted without contacting the through hole 42a. The shape of the through hole 42a may be rectangular or circular in plan view. The example of FIG. 2 shows a case where the through hole 42a is rectangular, which corresponds to the cross-sectional shape of the external connection terminal 11.

[0038] When used as terminal holes, the through holes 42a are formed in the lid 42 to correspond to the positions of the external connection terminals 11 in a plan view. The through holes 42a may be formed to correspond to the number of external connection terminals 11. The through holes 42a may also be holes used for purposes other than terminal holes. For example, in the case 40, another wiring board may be placed on the substrate 20 to position the two boards. In this case, the substrate 20 has a positioning opening on its front surface, and the wiring board has a through hole. Then, a rod-shaped positioning member is inserted into the opening on the front surface of the substrate 20, the through hole in the wiring board, and the through hole 42a in the lid 42 of the case 40 to perform positioning. The lid 42 may also have a plurality of through holes 42a for different purposes.

[0039] As shown in Fig. 2, the protrusions 43a to 43e surround the through hole 42a over multiple circumferences in a plan view, and are provided on the inner surface (rear surface) of the lid 42 without contacting the sealing member 35 as shown in Fig. 1. In the example of Fig. 2, the protrusions 43a to 43e are provided so as to surround the through hole 42a over multiple circumferences in an annular shape in a plan view. More specifically, the protrusions 43a to 43e are provided in the same number as the multiple circumferences in the long side direction of the rectangular heat dissipation plate 30, and also in the same number as the multiple circumferences in the short side direction of the heat dissipation plate 30. Furthermore, the outer shape of each of the protrusions 43a to 43e is rectangular in a plan view.

[0040] Fig. 3 is an enlarged view of the protrusions. Fig. 3 shows an enlarged view of protrusions 43d and 43e. The height of protrusions 43d and 43e is represented by H, the width by W, and the distance between adjacent protrusions 43d and 43e in the inner or outer circumferential direction is represented by G. Note that, hereinafter, the height of other protrusions 43a to 43c will also be represented by H, the width by W, and the distance between adjacent protrusions in the inner or outer circumferential direction by G.

[0041] Incidentally, in order to maintain the strength of the case 40, beams may be formed in a grid pattern on the inner surface of the lid 42. Furthermore, when there are multiple external connection terminals 11, beams may be provided between the terminals to maintain an insulating distance. In such a case 40, the protrusions 43a-43e may not necessarily have the function of maintaining the strength of the case 40 or the function of maintaining an insulating distance between the terminals, as the beams do. Furthermore, if the protrusions 43a-43e are too large, they may interfere with the fabrication of the beams. However, as will be described later (see FIGS. 5-7), the protrusions 43a-43e are required to act to prevent the liquid material contained in the sealing member 35 from reaching the through-hole 42a.

[0042] Considering the above, it is preferable that the height H of the protrusions 43a to 43e is 2 mm or less, and the spacing G is 0.5 mm or more and 1.5 mm or less. The height H and width W of the protrusions 43a to 43e do not necessarily have to be the same among the protrusions 43a to 43e. Also, all spacings G do not necessarily have to be the same. In the example shown in FIGS. 1 and 3, the protrusions 43a to 43e extend vertically from the inner surface of the lid 42 toward the storage area 40a, but this is not limiting. The protrusions 43a to 43e may be inclined within a range of approximately ±45° with respect to the -Z direction from the inner surface of the lid 42.

[0043] 2, the protrusions 43a to 43e surround the through-hole 42a over five laps in plan view, but this is not limiting. The lid 42 may have protrusions formed thereon that surround the through-hole 42a over two to four laps, or six or more laps.

[0044] The case 40 having the above-described protrusions 43a to 43e is made of resin. This resin is mainly composed of a thermoplastic resin. Examples of the thermoplastic resin include polyphenylene sulfide resin, polybutylene terephthalate resin, polybutylene succinate resin, polyamide resin, and acrylonitrile butadiene styrene resin. A filler may be added to such a resin. Examples of the filler include glass, silicon oxide, aluminum oxide, silicon nitride, and boron nitride. The case 40 is formed by filling a predetermined mold with such a resin, solidifying it, and then removing the mold. The side wall 41 and the lid 42 may be integrally molded. Alternatively, the side wall 41 and the lid 42 may be molded separately. In this case, the lid 42 is bonded to the upper part of the side wall 41 with an adhesive.

[0045] The lid portion 42 and the protrusions 43a to 43e may be integrally molded. Alternatively, the lid portion 42 and the protrusions 43a to 43e may be molded separately. When the lid portion 42 and the protrusions 43a to 43e are molded separately, the protrusions 43a to 43e are attached to predetermined locations on the flat lid portion 42, for example, with an adhesive. The lid portion 42 and the protrusions 43a to 43e may be made of different materials.

[0046] A cooling unit can be attached to the rear surface of such a semiconductor device 1 (more specifically, the rear surface of the heat sink 30) via a bonding material. This bonding material is solder, brazing material, or a sintered metal. Alternatively, the bonding material may be a thermal interface material. The thermal interface material is, for example, an adhesive material including an elastomer sheet, RTV (Room Temperature Vulcanization) rubber, gel, or phase change material. By attaching the cooling unit via such brazing material or thermal interface material, the heat dissipation performance of the semiconductor device 1 can be improved.

[0047] The cooling unit is, for example, a cooling device that uses a heat sink or a refrigerant for cooling. The heat sink may have multiple fins directly attached to the rear surface of the heat sink 30. Like the heat sink 30, the heat sink is also primarily composed of a metal with excellent thermal conductivity. The metal is, for example, copper, aluminum, or an alloy containing at least one of these.

[0048] Next, as a reference example of the semiconductor device 1, a semiconductor device that does not include the protruding portions 43a to 43e and its problems will be described with reference to FIG. 4 is a diagram illustrating creeping up of the sealing member in the semiconductor device of the reference example. The semiconductor device 100 shown in FIG. 4 is the semiconductor device 1 without the protrusions 43a to 43e. The other configuration of the semiconductor device 100 is the same as that of the semiconductor device 1.

[0049] As described above, the sealing member 35 of the semiconductor device 100 may contain a liquid material. For example, if the sealing member 35 is a silicone gel, the liquid material is a liquid low-molecular-weight siloxane. After the sealing member 35 hardens, the liquid material may seep onto the surface of the sealing member 35 as the semiconductor device 100 is used. One cause of this is that the components in the storage area 40a may repeatedly heat up and cool down due to repeated power supply and cutoff of the semiconductor chip 10, causing the sealing member 35 to expand and contract repeatedly. In this way, the application of mechanical pressure to the sealing member 35 may cause the liquid material to seep onto the surface of the sealing member 35.

[0050] The seeping liquid material may creep up the components in the storage area 40a that are in contact with the sealing member 35 due to capillary action. For example, the liquid material may creep up the inner wall of the side wall 41 of the case 40 upward (in the +Z direction). The liquid material may run from the side wall 41 of the case 40 along the back surface of the lid 42 and reach the through-hole 42a. The liquid material may seep out from the through-hole 42a to the outside. For example, such seepage of the liquid material may be discovered when maintenance is performed on the semiconductor device 100 or when a malfunction occurs 5 to 10 years after the semiconductor device 100 has been in use. The liquid material may also creep up the external connection terminal 11 upward (in the +Z direction) and seep out from the through-hole 42a to the outside.

[0051] The liquid material seeping out of the semiconductor device 100 from the through-hole 42a may contaminate the surrounding area and may also contaminate the operator when handling the semiconductor device 100. For example, if the sealing member 35 is a silicone gel, the amount of low-molecular-weight siloxane, which is the seeping liquid material, is approximately 1 wt % of the total amount of silicone gel. Therefore, it does not affect the insulation properties of the semiconductor device 100.

[0052] In contrast to the semiconductor device 100 of the reference example, the semiconductor device 1 includes the protrusions 43a to 43e, which makes it possible to prevent the liquid material of the sealing member 35 from seeping out of the semiconductor device 1, as will be described below.

[0053] FIG. 5 is a diagram illustrating the creeping up of the sealing member in the semiconductor device according to the first embodiment. 4, in the semiconductor device 1, the liquid material contained in the sealing member 35 creeps up the components in the +Z direction, running from the side wall portion 41 of the case 40 along the back surface of the lid portion 42 toward the through-hole 42a. However, unlike the case of the semiconductor device 100, in the semiconductor device 1, the liquid material does not reach the through-hole 42a unless it climbs over the protrusions 43a to 43e that surround the through-hole 42a in a plan view. This allows for a delay in the time it takes for the liquid material to reach the through-hole 42a.

[0054] From the above, it is possible to prevent the sealing member 35 from leaking out of the semiconductor device 1. Furthermore, even if the sealing member 35 does leak out, the amount of leakage can be reduced. Therefore, it is possible to prevent the ease of handling of the semiconductor device 1 from being reduced.

[0055] 6 is a diagram showing an example of the arrangement position of the protrusions relative to the direction of rising of the liquid material contained in the sealing member in the semiconductor device of the first embodiment. In FIG. 6, the arrows indicate the direction of rising of the liquid material that has risen from the four sidewalls 41 on the back surface of the lid 42.

[0056] The protrusions 43a to 43e include portions that extend in a direction perpendicular to the creeping-up direction of the liquid material contained in the sealing member 35. As shown in Fig. 6, the protrusions 43a to 43e include portions that extend in a direction perpendicular to the creeping-up direction in the ±Y directions (±X directions). The protrusions 43a to 43e also include portions that extend in a direction perpendicular to the creeping-up direction in the ±X directions (±Y directions).

[0057] The protrusions 43a to 43e have portions that extend perpendicular to the creeping direction, thereby efficiently impeding the progress of the liquid material contained in the sealing member 35 and further delaying the time it takes for the liquid material to reach the through-hole 42a.

[0058] Fig. 7 is a perspective view showing the liquid material spreading in the region where the protrusions are provided. As shown in Fig. 7, grooves are formed between each of the protrusions 43a to 43e. Therefore, the liquid material 35a contained in the sealing member 35 does not simply flow in one direction over the protrusions 43a to 43e toward the through-hole 42a, but also flows in the direction of the grooves.

[0059] For example, as shown in FIG. 7, the liquid material 35a that has climbed over the protrusion 43e spreads into the groove between the protrusions 43e and 43d, and accumulates in the groove to some extent before climbing over the next protrusion 43d.

[0060] By providing the protrusions 43a to 43e around the circumference, the grooves as described above are formed, which can further delay the liquid material 35a reaching the through-holes 42a.

[0061] [Second embodiment] Next, a semiconductor device according to a second embodiment will be described with reference to FIGS. Fig. 8 is a side cross-sectional view of the semiconductor device of the second embodiment. Fig. 9 is a top view showing a part of the semiconductor device of the second embodiment. Fig. 8 is a cross-sectional view taken along dashed line VIII-VIII in Fig. 9. In Fig. 9, the positions of grooves 44a to 44e formed on the inner surface of lid 42 are indicated by dashed lines. In Figs. 8 and 9, the same elements as those shown in Figs. 1 and 2 are denoted by the same reference numerals.

[0062] 8 and 9, in the semiconductor device 1a of the second embodiment, grooves 44a to 44e are formed in the lid portion 42 of the case 40 instead of the protrusions 43a to 43e shown in Figures 1 and 2. The grooves 44a to 44e extend from the inner surface (rear surface) of the lid portion 42 toward the outer surface (front surface) of the lid portion 42 that faces the inner surface.

[0063] As shown in Fig. 9, the grooves 44a to 44e surround the through hole 42a over multiple circumferences in a plan view, and are provided on the inner surface of the lid 42 without contacting the sealing member 35 as shown in Fig. 1. In the example of Fig. 9, the grooves 44a to 44e are provided so as to surround the through hole 42a over multiple circumferences in an annular shape in a plan view. More specifically, the grooves 44a to 44e are provided in the direction of the long sides of the rectangular heat dissipation plate 30 in the same number as the multiple circumferences, and also in the direction of the short sides of the heat dissipation plate 30 in the same number as the multiple circumferences. Furthermore, the outer shape of each of the grooves 44a to 44e is rectangular in a plan view.

[0064] Fig. 10 is an enlarged view of the grooves. Fig. 10 shows an enlarged view of grooves 44d and 44e. The depth of grooves 44d and 44e is represented by D, the width by W, and the distance between adjacent grooves 44d and 44e in the inner or outer circumferential direction is represented by G. Note that, hereinafter, the depth of other grooves 44a to 44c will also be represented by D, the width by W, and the distance between adjacent grooves in the inner or outer circumferential direction by G.

[0065] If the size of the grooves 44a to 44e is too large, it may reduce the strength of the case 40. However, as will be described later (see FIG. 11), the grooves 44a to 44c are required to act to prevent the liquid material contained in the sealing member 35 from reaching the through-hole 42a.

[0066] Considering the above, it is preferable that the depth D of the grooves 44a to 44e is 1 mm or less, and the spacing G is 0.5 mm or more and 1.5 mm or less. Note that the depth D and width W do not necessarily have to be the same among the grooves 44a to 44e. Also, all spacings G do not necessarily have to be the same. Also, in the example shown in FIGS. 9 and 10, the grooves 44a to 44e extend vertically from the inner surface to the outer surface of the lid 42, but this is not a limitation. The grooves 44a to 44e may be inclined within a range of approximately ±45° with respect to the +Z direction from the inner surface of the lid 42.

[0067] 10, the grooves 44a to 44e surround the through-hole 42a over five peripheries in plan view, but this is not limited to this. The lid 42 may have grooves formed therein that surround the through-hole 42a over two to four peripheries or six or more peripheries. The lid 42 and the grooves 44a to 44e are integrally molded.

[0068] In contrast to the reference example semiconductor device 100 shown in Figure 4, the semiconductor device 1a of the second embodiment includes the groove portions 44a to 44e as described above, which prevents the liquid material from seeping out of the semiconductor device 1a as described below.

[0069] FIG. 11 is a diagram illustrating the creeping up of the sealing member in the semiconductor device according to the second embodiment. In the semiconductor device 1a, the liquid material contained in the sealing member 35 creeps up the components in the +Z direction, similar to the case of FIG. 4, from the side wall portion 41 of the case 40 along the back surface of the lid portion 42 toward the through-hole 42a. However, unlike the semiconductor device 100, in the semiconductor device 1a, the liquid material does not reach the through-hole 42a without climbing over the groove portions 44a-44e that surround the through-hole 42a in a plan view. This delays the time it takes for the liquid material to reach the through-hole 42a. From the above, similar to the semiconductor device 1 of the first embodiment, the semiconductor device 1a of the second embodiment can suppress leakage of the sealing member 35 to the outside of the semiconductor device 1a.

[0070] Although not shown, the grooves 44a to 44e may include portions that extend perpendicular to the direction in which the liquid material contained in the sealing member 35 creeps up, similar to the protrusions 43a to 43e. That is, the grooves 44a to 44e include portions that extend perpendicular to the direction in which the liquid material creeps up in the ±Y directions (±X directions). The grooves 44a to 44e also include portions that extend perpendicular to the direction in which the liquid material creeps up in the ±X directions (±Y directions).

[0071] Grooves 44a to 44e have portions that extend perpendicular to the creeping direction, thereby efficiently impeding the progress of the liquid material contained in sealing member 35 and further delaying the time it takes for the liquid material to reach through-hole 42a.

[0072] Furthermore, the grooves 44a to 44e act in the same manner as the grooves between the protrusions 43a to 43e shown in Fig. 7. That is, the liquid material contained in the sealing member 35 does not simply flow in one direction over the grooves 44a to 44e toward the through-hole 42a, but also flows in the extension direction of the grooves 44a to 44e.

[0073] 11, the liquid material that creeps up the side wall 41 first spreads along the inner surface of the lid 42 into the groove 44e. After the liquid material accumulates in the groove 44e to a certain extent, it flows into the next groove 44d. By providing the grooves 44a to 44e in multiple laps, it is possible to further delay the liquid material reaching the through-hole 42a.

[0074] (First Modification) Next, a semiconductor device according to a first modification will be described with reference to FIG. Fig. 12 is a side cross-sectional view of the semiconductor device of the first modified example, in which the same elements as those shown in Fig. 1 or 8 are denoted by the same reference numerals.

[0075] The semiconductor device 1b of the first modification shows an example in which the inner surface of the lid 42 of the case 40 is provided with a mixture of the protrusions 43a and 43b of the semiconductor device 1 of the first embodiment and the grooves 44c to 44e of the semiconductor device 1a of the second embodiment. In the example of FIG. 12, the protrusions 43a and 43b are formed on the inner periphery, and the grooves 44c to 44e are formed on the outer periphery. However, the mixture of the protrusions and grooves is not limited to the above example. For example, the following applications are conceivable.

[0076] Depending on the lid portion 42 of the case 40, the thickness may vary depending on the location. In areas where the thickness is thin, it may be impossible to form a groove of an appropriate depth. In such areas, a protrusion may be formed. Conversely, in areas where the thickness of the lid portion 42 is thick, if a protrusion is provided, the tip of the protrusion may come into contact with the surface of the sealing member 35. In such areas, a groove may be formed. Alternatively, in cases where a beam is formed on the inner surface of the lid portion 42 of the case 40, and if a protrusion like that of the semiconductor device 1 of the first embodiment is provided, a groove may be formed in areas where the beam would interfere with the protrusion.

[0077] In this way, even if the protrusions and grooves are mixed, the same effects as those of the semiconductor device 1 of the first embodiment or the semiconductor device 1a of the second embodiment can be obtained.

[0078] (Second Modification) Next, a semiconductor device according to a second modification will be described with reference to FIG. Fig. 13 is a top view showing a part of the semiconductor device of the second modification. The cross section taken along the dashed line II in Fig. 13 has the same configuration as the cross-sectional side view in Fig. 1, and is therefore not shown. In Fig. 13, the same elements as those shown in Fig. 2 are denoted by the same reference numerals.

[0079] In the semiconductor device 1, 1a shown in Figure 1 or Figure 8, an example is shown in which annular protrusions 43a to 43e (Figure 2) or grooves 44a to 44e (Figure 9) are formed on the inner surface of the lid portion 42, but the shape of the protrusions and grooves in a planar view is not limited to the above forms.

[0080] 13, the protrusion 43 of the semiconductor device 1c of the second modification may be provided so as to surround the through-hole 42a in a spiral shape over multiple revolutions in a plan view. Note that instead of the protrusion 43, a groove may be provided so as to surround the through-hole 42a in a spiral shape over multiple revolutions in a plan view.

[0081] Even when such a protrusion 43 (or groove) is provided, the liquid material seeping out of the sealing member 35 is prevented from reaching the through-hole 42a by the protrusion 43, so that an effect similar to that of the protrusions 43a to 43e or grooves 44a to 44e described above can be obtained.

[0082] (Third Modification) Next, a semiconductor device according to a third modification will be described with reference to FIG. Fig. 14 is a side cross-sectional view of a semiconductor device according to a third modification. Fig. 15 is a top view showing a portion of the semiconductor device according to the third modification. Fig. 14 is a cross-sectional view taken along dashed line XIV-XIV in Fig. 15. In Fig. 15, the positions of grooves 44a1-44e1, 44a2-44e2, and 44a3-44e3 formed on the inner surface of lid 42 are indicated by dashed lines. In Fig. 14, the same elements as those shown in Fig. 1 or 8 are designated by the same reference numerals.

[0083] In the semiconductor devices 1 and 1a shown in FIGS. 1 and 8, only one substrate 20 (on which a semiconductor chip 10 and external connection terminals 11 are mounted) is provided in the Y direction, but the present invention is not limited to this. A semiconductor device 1d of a third modification has three substrates 20a to 20c provided in the Y direction. The substrates 20a to 20c correspond to the substrate 20 shown in FIGS. 1 and 8, respectively. The external connection terminals 11a to 11c mounted on the substrates 20a to 20c correspond to the external connection terminals 11 shown in FIGS. 1 and 8, respectively. The semiconductor chips 10a to 10c mounted on the substrates 20a to 20c correspond to the semiconductor chip 10 shown in FIGS. 1 and 8, respectively. The external connection terminals 11a to 11c mounted on the substrates 20a to 20c correspond to the external connection terminals 11 shown in FIGS. 1 and 8, respectively.

[0084] The semiconductor chip 10a mounted on the substrate 20a is mechanically and electrically connected to the substrate 20a by bonding wires 25a. The semiconductor chip 10b mounted on the substrate 20b is mechanically and electrically connected to the substrate 20b by bonding wires 25b. The semiconductor chip 10c mounted on the substrate 20c is mechanically and electrically connected to the substrate 20c by bonding wires 25c. At least one of switching elements and diode elements is selected from the semiconductor chips 10a to 10c as necessary, and the back surfaces of the chips are directly bonded to predetermined circuit patterns 22a to 22c of the substrates 20a to 20c by bonding members 24a to 24c.

[0085] The external connection terminal 11a mounted on the substrate 20a is electrically connected to one of the main electrodes or control electrodes of the semiconductor chip 10a. The inner end of the external connection terminal 11a is bonded to the substrate 20a, and the outer end of the external connection terminal 11a extends outward from a through-hole 42a1 provided in the lid portion 42 of the case 40. The external connection terminal 11b mounted on the substrate 20b is electrically connected to one of the main electrodes or control electrodes of the semiconductor chip 10b. The inner end of the external connection terminal 11b is bonded to the substrate 20b, and the outer end of the external connection terminal 11b extends outward from a through-hole 42a2 provided in the lid portion 42 of the case 40. The external connection terminal 11c mounted on the substrate 20c is electrically connected to one of the main electrodes or control electrodes of the semiconductor chip 10c. An inner end of the external connection terminal 11c is joined to the substrate 20c, and an outer end of the external connection terminal 11c extends outward from a through-hole 42a3 provided in the lid 42 of the case 40. When the semiconductor device 1d is a three-phase inverter device, the three external connection terminals 11a to 11c may be used as, for example, U, V, and W three-phase inverter output terminals.

[0086] Substrate 20a includes insulating plate 21a, circuit pattern 22a, and metal plate 23a. Substrate 20b includes insulating plate 21b, circuit pattern 22b, and metal plate 23b. Substrate 20c includes insulating plate 21c, circuit pattern 22c, and metal plate 23c.

[0087] Three through holes 42a1 to 42a3 are formed in the lid 42 of the case 40 in the Y direction. Each of the through holes 42a1 to 42a3 corresponds to the through hole 42a shown in FIGS. 1, 2, 8, and 9. In the example of FIGS. 14 and 15, the through hole 42a1 is used as a terminal hole through which the outer end of the external connection terminal 11a is inserted. The through hole 42a2 is used as a terminal hole through which the outer end of the external connection terminal 11b is inserted. The through hole 42a3 is used as a terminal hole through which the outer end of the external connection terminal 11c is inserted.

[0088] Groove portions 44a1 to 44e1 are formed so as to surround through hole 42a1 over multiple peripheries in a plan view, as shown in Fig. 15. Groove portions 44a2 to 44e2 are formed so as to surround through hole 42a2 over multiple peripheries in a plan view, as shown in Fig. 15. Groove portions 44a3 to 44e3 are formed so as to surround through hole 42a3 over multiple peripheries in a plan view, as shown in Fig. 15. Groove portions 44a1 to 44e1, 44a2 to 44e2, and 44a3 to 44e3 correspond to groove portions 44a to 44e shown in Figs. 8 and 9.

[0089] By providing the grooves 44a1 to 44e1, 44a2 to 44e2, and 44a3 to 44e3 as described above, leakage of the sealing member 35 through the through holes 42a1 to 42a3 can be suppressed.

[0090] In the semiconductor device 1d of the third modified example, the protrusions 43a to 43e shown in FIGS. 1 and 2 may be used instead of the grooves 44a1 to 44e1, 44a2 to 44e2, and 44a3 to 44e3.

[0091] 15, the positions of beams 45a, 45b, and 45c, which are some of the beams formed on the inner surface of lid portion 42, are indicated by dashed lines. Beam 45a extends in the Y direction on the inner surface of lid portion 42. Both ends of beam 45a abut against portions of side wall 41 of case 40 that face each other in the Y direction. Beam 45b extends in the X direction on the inner surface of lid portion 42 between grooves 44a1 to 44e1 and grooves 44a2 to 44e2 in a plan view. One end of beam 45b abuts against a portion of side wall 41 that extends in the Y direction, and the other end of beam 45b abuts against beam 45a. Beam 45c extends in the X direction on the inner surface of lid portion 42 between grooves 44a2 to 44e2 and grooves 44a3 to 44e3 in a plan view. One end of the beam 45c abuts against a portion of the side wall 41 extending in the Y direction, and the other end of the beam 45c abuts against the beam 45a.

[0092] To distinguish them from the protrusions 43a to 43e shown in Figures 1 and 2, beams can refer to a plurality of protrusions that have a height (length in the Z direction) of 2 mm or more, a width of 1 mm or more, and adjacent protrusions spaced 1 mm or more apart. For example, the height of beams 45a to 45c shown in Figure 15 is 2 mm to 10 mm, and the width of beams 45a to 45c is 1 mm to 5 mm.

[0093] By providing such beams 45a to 45c, the strength of the case 40 can be maintained, and the insulation distance between the external connection terminals 11a to 11c can be maintained.

[0094] While one aspect of the semiconductor device of the present invention has been described above based on the embodiment, these are merely examples and the present invention is not limited to the above description. [Explanation of symbols]

[0095] 1, 1a to 1d, 100 Semiconductor device 10, 10a to 10c Semiconductor chips 11, 11a to 11c External connection terminal 20, 20a to 20c Substrate 21, 21a to 21c Insulating plate 22, 22a to 22c Circuit pattern 23,23a~23c metal plate 24, 24a to 24c Joint members 25, 25a~25c Bonding Wire 26 Adhesive 30 Heat sink 35 Sealing member 35a Liquid materials 40 cases 40a Storage area 41 Side wall 42 Lid 42a,42a1~42a3 Through hole 43,43a~43e Protrusion 44,44a~44e,44a1~44e1,44a2~44e2,44a3~44e3 Groove 45a~45c Beam

Claims

1. a substrate on which a semiconductor chip is mounted; a heat sink disposed on the front surface of the substrate; a case including a side wall portion disposed on the front surface of the heat sink so as to surround a storage area including the substrate together with the heat sink, and a lid portion disposed on the side wall portion and covering the storage area; a sealing member filled in the storage area and sealing the substrate; Equipped with The lid portion is A through hole; a protrusion or groove portion that surrounds the through hole over multiple peripheries in a plan view and is provided on the inner surface of the lid portion without contacting the sealing member; A semiconductor device having:

2. 2. The semiconductor device according to claim 1, wherein said protrusion or said groove includes a portion extending in a direction perpendicular to a direction in which said liquid material contained in said sealing member creeps up.

3. 2. The semiconductor device according to claim 1, wherein said sealing member is a silicone gel containing a liquid low-molecular-weight siloxane.

4. The semiconductor device according to claim 1 , wherein the protrusion or the groove is provided so as to surround the through hole in a ring shape over a plurality of circumferences in a plan view.

5. The semiconductor device according to claim 1 , wherein the protrusion or the groove is provided so as to surround the through hole in a spiral shape over a plurality of circumferences in a plan view.

6. 2. The semiconductor device according to claim 1, wherein the protrusions have a height of 2 mm or less, a width of 0.5 mm to 1.5 mm, and an interval between adjacent protrusions in the inner or outer circumferential direction is 0.5 mm to 1.5 mm.

7. 2. The semiconductor device according to claim 1, wherein the groove has a depth of 1 mm or less, a width of 0.5 mm to 1.5 mm, and an interval between adjacent grooves in the inner or outer circumferential direction is 0.5 mm to 1.5 mm.

8. 2. The semiconductor device according to claim 1, wherein an inner end is bonded to the substrate, and an outer end includes an external connection terminal extending outward from the through hole.

9. The heat sink is rectangular, the projections or grooves are provided in the same number as the number of circumferences of the heat sink in the long side direction, The heat sink is also provided with the same number of protrusions or grooves as the number of circumferences in the short side direction. The semiconductor device according to claim 1 .

Images