JP2016092099A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which can inhibit an increase in plane size of a frame where a plurality of semiconductor switching elements are mounted and obtain favorable electrical characteristics.SOLUTION: A semiconductor device comprises: a frame having first and second frame principal surfaces; a support substrate which has first and second substrate principal surfaces and is arranged away from the frame in a manner such that the second substrate principal surface faces the first frame principal surface; a plurality of semiconductor elements each of which has a structure where first and second semiconductor switching elements are layered, and which are mounted on corners of the first frame principal surface separately in a manner such that the side of the first semiconductor switching element faces the first frame principal surface and the side of the second semiconductor switching element faces the second substrate principal surface; and a control element mounted on the first substrate principal surface, for controlling behaviors of the first semiconductor switching element and the second semiconductor switching element.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a semiconductor device including a plurality of semiconductor switching elements.

  A method for suppressing the planar size of a frame on which a plurality of semiconductor switching elements are mounted by laminating semiconductor switching elements constituting a semiconductor device has been studied. For example, for an H-type bridge circuit composed of four semiconductor switching elements, a method for obtaining good heat dissipation characteristics while stacking semiconductor switching elements has been proposed (for example, see Patent Document 1).

Japanese Patent No. 4061551

  However, a method for obtaining good electrical characteristics while suppressing an increase in the planar size of the frame on which the semiconductor switching element is mounted is not sufficient. For example, when the number of semiconductor switching elements constituting a semiconductor device exceeds four, the method described in Patent Document 1 does not show an optimal layout for obtaining good electrical characteristics.

  In view of the above problems, an object of the present invention is to provide a semiconductor device capable of suppressing an increase in the planar size of a frame on which a plurality of semiconductor switching elements are mounted and obtaining good electrical characteristics. And

  According to one aspect of the present invention, (a) a frame having a first frame main surface and a second frame main surface facing each other, and (a) a first substrate main surface and a second substrate facing each other. A support substrate having a main surface and being spaced apart from the frame so that the second substrate main surface opposes the first frame main surface; and (c) a first semiconductor switching element and a second semiconductor. Each of the switching elements has a stacked structure, and the first semiconductor switching element side faces the first frame main surface and the second semiconductor switching element side faces the second substrate main surface. A plurality of semiconductor element units respectively mounted on different corner portions of one frame main surface; and (d) operations of the first semiconductor switching element and the second semiconductor switching element mounted on the first substrate main surface. Control Semiconductor device and a control device is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the semiconductor device which can suppress the increase in the planar size of the flame | frame in which several semiconductor switching elements are mounted, and can acquire a favorable electrical property can be provided.

It is a typical side view showing the structure of the semiconductor device concerning the embodiment of the present invention. It is a schematic diagram which shows the example of the heat sink of the semiconductor device which concerns on embodiment of this invention. 1 is a schematic plan view showing a structure of a semiconductor device according to an embodiment of the present invention. It is a schematic diagram which shows the layout of the semiconductor device of a comparative example. It is a typical side view showing the structure of the semiconductor device concerning the embodiment of the present invention. It is a schematic diagram which shows the usage example of the semiconductor device which concerns on embodiment of this invention. FIGS. 7A and 7B are schematic views showing connections between switching elements and external terminals in a semiconductor device according to a modification of the embodiment of the present invention, in which FIG. 7A is a side view and FIG.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the lengths of the respective parts, and the like are different from the actual ones. Therefore, specific dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  The following embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention includes the shape, structure, arrangement, etc. of components. It is not specified to the following. The embodiment of the present invention can be variously modified within the scope of the claims.

  As shown in FIG. 1, a semiconductor device 1 according to an embodiment of the present invention includes a frame 10 having a first frame main surface 11 and a second frame main surface 12 facing each other, and a first substrate facing each other. A support substrate 20 having a main surface 21 and a second substrate main surface 22 is provided. The support substrate 20 is disposed away from the frame 10 so that the second substrate main surface 22 faces the first frame main surface 11. A plurality of semiconductor element units 30 are mounted on the first frame main surface 11 between the frame 10 and the support substrate 20.

  The semiconductor element unit 30 has a structure in which a first semiconductor switching element 311 and a second semiconductor switching element 312 are stacked. As shown in FIG. 1, the first semiconductor switching element 311 side of the semiconductor element unit 30 faces the first frame main surface 11, and the second semiconductor switching element 312 side faces the second substrate main surface 22. doing. The semiconductor element unit 30 is supported on the support substrate 20 by a convex support portion 221 formed on the second substrate main surface 22 of the support substrate 20.

  The semiconductor device 1 further includes a control element 40 mounted on the first substrate main surface 21 of the support substrate 20. The control element 40 controls the operations of the first semiconductor switching element 311 and the second semiconductor switching element 312.

  Hereinafter, the first semiconductor switching element 311 and the second semiconductor switching element 312 are collectively referred to as “semiconductor switching element 31”. The semiconductor switching element 31 is a self-extinguishing element whose on / off state is switched by a control signal from the outside. For example, transistors such as MOS field effect transistors (MOSFETs), insulated gate bipolar (IGBT), bipolar transistors, and thyristors.

  Hereinafter, a case where the semiconductor switching element 31 is a MOSFET will be described as an example. In FIG. 1, the first main electrode (drain electrode) of the semiconductor switching element 31 is indicated by reference sign D, the second main electrode (source electrode) is indicated by reference sign S, and the control terminal (gate electrode) is indicated by reference sign G (hereinafter referred to as “G”). The same as in). A drain electrode D is formed on one main surface of the semiconductor switching element 31, and a source electrode S is formed on the other main surface. A gate electrode G is formed on the main surface of the semiconductor switching element 31 in the remaining region where the source electrode S is formed.

  The drain electrode D of the first semiconductor switching element 311 is electrically connected to the first frame main surface 11. For example, the main surface on which the drain electrode D of the first semiconductor switching element 311 is formed is bonded to the first frame main surface 11 with a conductive adhesive or the like. The material of the frame 10 is a conductive material, for example, a metal material such as copper (Cu) or aluminum (Al).

  The source electrode S of the first semiconductor switching element 311 and the drain electrode D of the second semiconductor switching element 312 are electrically connected. For example, the main surface on which the source electrode S of the first semiconductor switching element 311 is formed and the main surface on which the drain electrode D of the second semiconductor switching element 312 is formed by a conductive adhesive (not shown). Glue.

  In addition, as shown in FIG. 2, you may laminate | stack the 1st semiconductor switching element 311 and the 2nd semiconductor switching element 312 via the heat sink 32 which has electroconductivity. Thereby, the heat dissipation characteristics can be improved, and the second semiconductor switching element 312 can be stably fixed on the first semiconductor switching element 311. The heat sink 32 is fixed between the first semiconductor switching element 311 and the second semiconductor switching element 312 with, for example, a conductive adhesive. As a result, the source electrode S of the first semiconductor switching element 311 and the drain electrode D of the second semiconductor switching element 312 are electrically connected.

  The gate electrode G of the semiconductor switching element 31 is formed on the main surface facing the second semiconductor switching element 312. Therefore, in order to expose the gate electrode G of the first semiconductor switching element 311, the area of the main surface of the second semiconductor switching element 312 is set smaller than the area of the main surface of the first semiconductor switching element 311. Has been. The gate electrode G of the first semiconductor switching element 311 is disposed in the remaining area in contact with the second semiconductor switching element 312. Further, the gate electrode G of the second semiconductor switching element 312 is disposed on the main surface opposite to the second substrate main surface 22 in the remaining region in contact with the support portion 221.

  The gate electrode G of the semiconductor switching element 31 and the signal output terminal C of the control element 40 are electrically connected, for example, by a bonding wire 400 as shown in FIG. Thereby, the operation of the first semiconductor switching element 311 and the second semiconductor switching element 312 is controlled by the control signal output from the control element 40. For example, the control element 40 controls the first semiconductor switching element 311 and the second semiconductor switching element 312 so that the first semiconductor switching element 311 and the second semiconductor switching element 312 are alternately turned on and off. The

  The material of the support substrate 20 on which the control element 40 is mounted may be a conductive material or an insulating material. In order to obtain good heat dissipation characteristics, it is preferable to use a metal material such as Cu or Al for the support substrate 20. However, when a conductive material is used for the support substrate 20 and it is necessary to electrically insulate between the control element 40 and the support substrate 20, for example, the control element 40 is supported on the support substrate 20 by an insulating adhesive. Adhere to.

  The support part 221 is integrally formed with the main body of the support substrate 20, for example. If the support substrate 20 is made of a conductive material and it is not desired to electrically connect the support substrate 20 and the semiconductor element unit 30, the support portion 221 and the semiconductor element unit 30 are connected by an insulating adhesive. To do. Alternatively, an insulating material may be sandwiched between the support portion 221 and the semiconductor element unit 30. On the other hand, when the support substrate 20 and the semiconductor element unit 30 are electrically connected, the support portion 221 and the semiconductor element unit 30 are connected by a conductive adhesive. Thereby, for example, the GND of the semiconductor element unit 30 and the support substrate 20 can be made common.

  In the semiconductor device 1, a plurality of external terminals 50 are arranged along the outer edge of the first frame main surface 11. Power supply terminals and input / output terminals of the semiconductor switching element 31 and the control element 40 are electrically connected to the external terminal 50, and power supply and signal input / output from the outside of the semiconductor device 1 are performed via the external terminal 50. . For example, the output terminal of the semiconductor switching element 31 and the external terminal 50 are electrically connected by a lead wire. That is, as shown in FIG. 1, the source electrode S of the first semiconductor switching element 311 is electrically connected to the external terminal 50 via the lead wire 501, and the source electrode S of the second semiconductor switching element 312 is the lead It is electrically connected to the external terminal 50 through a line 502.

  Meanwhile, the semiconductor device 1 shown in FIG. 1 further includes a conversion substrate 60 that electrically connects the terminal of the control element 40 and the external terminal 50. The conversion board 60 is mounted on the first frame main surface 11 in the remaining area of the area where the semiconductor element unit 30 is arranged. An internal lead 61 is formed on the upper surface of the conversion substrate 60, the terminal T of the control element 40 and the internal lead 61 are connected by a bonding wire 401, and the internal lead 61 and the external terminal 50 are connected by a bonding wire 402. . By mounting the conversion substrate 60 on the frame 10, the length of the bonding wire connecting the control element 40 and the external terminal 50 can be shortened. As a result, for example, it is possible to prevent a problem that the bonding wires are entangled with each other or a short circuit failure caused by the bonding wires occurs.

  In the semiconductor device 1, the support substrate 20, the semiconductor element unit 30, and the control element 40 are molded and sealed with a sealing body 70 such as an epoxy resin. Note that the second frame main surface 12 of the frame 10 is preferably exposed to the outside of the sealing body 70. Thereby, the heat dissipation characteristic can be improved. A part of the external terminal 50 is exposed to the outside of the sealing body 70 and used as an external lead.

  The semiconductor device 1 shown in a plan view in FIG. 3 includes three semiconductor element units 30. As shown in FIG. 3, the first frame main surface 11 is rectangular in plan view, and the first semiconductor element unit 301 and the second semiconductor element unit are formed at three corners of the first frame main surface 11. 302 and a third semiconductor element unit 303 are respectively mounted. In FIG. 3, illustration of electrodes, terminals, bonding wires, and the like of each element is omitted.

  As shown in FIG. 3, a plurality of external terminals 50 are arranged along the four sides of the outer edge of the first frame main surface 11. And the terminal of the 1st semiconductor switching element 311 is electrically connected to the external terminal 50 arrange | positioned at one edge | side of two adjacent sides in the corner part of the 1st frame main surface 11, and it arrange | positions at the other edge | side. The terminal of the second semiconductor switching element 312 is electrically connected to the external terminal 50 thus formed. As described above, the output from the first semiconductor switching element 311 and the output from the second semiconductor switching element 312 are distributed to the external terminals 50 arranged on two adjacent sides of the corner portion. At this time, the terminal of the semiconductor switching element 31 is electrically connected to the external terminal 50 arranged close to the corner portion. Thereby, the distance of the electrical path from the semiconductor switching element 31 to the external terminal 50 can be shortened. For this reason, good electrical characteristics can be obtained. In FIG. 3, only one lead wire 501 and 502 is shown, but a plurality of lead wires 501 and 502 may be connected in parallel.

  By arranging the semiconductor element unit 30 at the corner portion of the first frame main surface 11 as described above, in the semiconductor device 1, the length of the lead wire 501 connecting the first semiconductor switching element 311 and the external terminal 50. In addition, the length of the lead wire 502 connecting the second semiconductor switching element 312 and the external terminal 50 can be made uniform and as short as possible. As a result, it is possible to stably flow a large current through the lead wire and to suppress variations in signal delay.

  On the other hand, for example, as shown in FIG. 4, when three or more semiconductor element units 30 are arranged along the outer side of the first frame main surface 11, the semiconductor element units that are not arranged in the corner portion. In 30B, there is a large difference in length between the electrical path R1 from the first semiconductor switching element 311 to the external terminal 50 and the electrical path R2 from the second semiconductor switching element 312 to the external terminal 50. In this case, in order to make the length of the electric path R1 and the electric path R2 equal, it is necessary to match the length of the electric path with the longer electric path. Further, when the length of the electrical path in the semiconductor element unit 30B is adjusted to the longer one, the electrical path between the semiconductor element unit 30A and the semiconductor element unit 30C disposed in the corner portion and the semiconductor element unit 30B. There is a difference in length. Therefore, in the arrangement of the semiconductor element unit 30 shown in FIG.

  On the other hand, according to the semiconductor device 1, each of the semiconductor element units 30 is mounted at a different corner portion of the first frame main surface 11, and the semiconductor element unit 30 is connected to the external terminal 50 adjacent to the corner portion. Therefore, good electrical characteristics can be obtained.

  Furthermore, in the semiconductor device 1, the control element 40 that controls the operation of the semiconductor element unit 30 is disposed above the semiconductor element unit 30 via the support substrate 20. For this reason, the distance between each semiconductor element unit 30 and the control element 40 can be made uniform and short. Thereby, the electrical characteristics of the semiconductor device 1 can be improved.

  In the layout example shown in FIG. 3, the conversion substrate 60 is mounted on the first frame main surface 11 in the corner portion of the first frame main surface 11 where the semiconductor element unit 30 is not disposed. Has been. In other words, in the semiconductor device 1, the semiconductor element units 30 are arranged at three places among the four corners of the rectangular frame 10, and the conversion substrate 60 is arranged at the other one place.

  Further, in the example shown in FIGS. 1 and 3, the corner portion of the support substrate 20 located above the conversion substrate 60 is cut obliquely to provide a notch. Then, the end portion of the support portion 222 extending in the frame 10 direction from the notched portion is brought into contact with the upper surface of the conversion substrate 60. As described above, the support substrate 20 is stabilized by bending a part of the corner portion of the support substrate 20 downward and fixing the tip of the corner to the upper surface of the conversion substrate 60.

  However, the semiconductor element unit 30 may be disposed at all four corner portions of the first frame main surface 11. The number of the semiconductor element units 30 included in the semiconductor device 1 having the rectangular first frame main surface 11 is selected from 2 to 4 depending on the function of the semiconductor device 1.

  In the semiconductor device 1 shown in FIG. 3, a plurality of external terminals 50 are arranged along the four sides of the outer edge of the first frame main surface 11. Therefore, the package of the semiconductor device 1 is preferably a package having a structure in which the external terminals 50 extend outward from opposite sides of the rectangular frame 10. Thereby, the semiconductor device 1 can be reduced in size optimally. For example, a QFP (Quad Flat Package) type package or the like can be suitably used for the semiconductor device 1.

  1 corresponds to a side view seen from the X direction in FIG. In order to clarify the structure of the semiconductor device 1, FIG. 5 shows a drawing corresponding to a side view seen from the Y direction in FIG.

  As described above, in the semiconductor device 1 according to the embodiment of the present invention, the semiconductor element unit 30 in which the semiconductor switching elements 31 are stacked is disposed at the corner portion of the frame 10. Then, the semiconductor element unit 30 is connected to the external terminal 50 disposed in the vicinity of the corner portion. Thereby, the distance of the electrical path to the 1st semiconductor switching element 311 and the external terminal 50 and the distance of the electrical path to the 2nd semiconductor switching element 312 and the external terminal 50 can be made equal and short. Further, variation in the length of the electrical path between the semiconductor element units 30 is reduced. As a result, according to the semiconductor device 1, an increase in the planar size of the frame 10 on which the semiconductor switching element 31 is mounted can be suppressed, and good electrical characteristics can be obtained. In the semiconductor device 1, since the length of the lead wire connecting the semiconductor element unit 30 and the external terminal 50 can be shortened, the semiconductor device 1 is particularly preferably used when supplying a large current from the semiconductor element unit 30. .

  The semiconductor device 1 is used as a control device for a three-phase motor 100, for example, as shown in FIG. That is, the semiconductor device 1 has three semiconductor element units 30, and each of the semiconductor element units 30 controls each phase output of the three-phase motor 100.

  Specifically, a connection point between the first semiconductor switching element 311 and the second semiconductor switching element 312 is used as an output terminal of the semiconductor element unit 30, and this output terminal is connected to each phase of the three-phase motor 100. That is, the output terminal of the first semiconductor element unit 301 is connected to the first phase circuit 101 of the three-phase motor 100, the output terminal of the second semiconductor element unit 302 is connected to the second phase circuit 102, The output terminal of the third semiconductor element unit 303 is connected to the third phase circuit 103. Then, the operation of the three-phase motor 100 is controlled by controlling the first semiconductor element unit 301, the second semiconductor element unit 302, and the third semiconductor element unit 303 by the control element 40. At this time, the first semiconductor switching element 311 and the second semiconductor switching element 312 are alternately turned on and off under the control of the control element 40.

  The operation of the three-phase motor 100 may be controlled by the semiconductor device 1 having four semiconductor element units 30. For example, the semiconductor element unit 30 that converts an external power supply voltage into a predetermined power supply voltage is mounted on the frame 10 separately from the three semiconductor element units 30 connected to the phase circuit. At this time, the four semiconductor element units 30 are respectively arranged at the corners of the first frame main surface 11.

<Modification>
In the semiconductor device 1 described above, the output terminal of the semiconductor switching element 31 and the external terminal 50 are connected by a lead wire. On the other hand, as shown in FIGS. 7A and 7B, the output terminal of the semiconductor switching element 31 and the external terminal 50 may be connected by a clip lead. The “clip lead” is made of a plate-like conductive material and can be bent. As the material of the clip lead, for example, a metal material such as Cu or Al is used.

  FIG. 7A and FIG. 7B show the second semiconductor in which the source electrode S (not shown) of the first semiconductor switching element 311 and the external terminal 50 are electrically connected via the clip lead 511. In this example, the source electrode S (not shown) of the switching element 312 and the external terminal 50 are electrically connected via a clip lead 512.

  The clip lead has a lower resistance than the lead wire. For this reason, by using a clip lead for electrical connection, it is possible to flow a large current stably as compared with the case of using a lead wire. In addition, the impedance and inductance of the electrical path can be reduced.

  Further, by arranging one end of the clip lead between the first semiconductor switching element 311 and the second semiconductor switching element 312, the clip lead can also be used as a heat sink.

  In the above, an example in which clip leads are used for the connection between the first semiconductor switching element 311 and the external terminal 50 and the connection between the second semiconductor switching element 312 and the external terminal 50 has been described. However, only one of these connections may be made by a clip lead, and the other connection may be made by a lead wire.

(Other embodiments)
As mentioned above, although this invention was described by embodiment, it should not be understood that the description and drawing which form a part of this indication limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the description of the embodiment already described, an example in which the semiconductor switching element 31 is a MOSFET has been shown. On the other hand, the semiconductor switching element 31 may be another type of FET, IGBT, bipolar transistor, or the like. Or you may comprise the semiconductor element unit 30 by mixing said transistor.

  Further, the first frame main surface 11 may be a polygon having another shape instead of a rectangular shape. Even in this case, good electrical characteristics can be obtained by disposing the semiconductor element unit 30 in the corner portion.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 ... Semiconductor device 10 ... Frame 20 ... Support substrate 30 ... Semiconductor element unit 32 ... Heat sink 40 ... Control element 50 ... External terminal 60 ... Conversion board 70 ... Sealing body 221 ... Support part 311 ... 1st semiconductor switching element 312 ... 2nd semiconductor switching element 501, 502 ... Lead wire 511, 512 ... Clip lead

Claims (11)

A frame having a first frame main surface and a second frame main surface facing each other;
A support having a first substrate main surface and a second substrate main surface facing each other, and being spaced apart from the frame so that the second substrate main surface faces the first frame main surface A substrate,
Each of the first semiconductor switching element and the second semiconductor switching element has a stacked structure, and the first semiconductor switching element side faces the first frame main surface, and the second semiconductor switching element has a structure. A plurality of semiconductor element units mounted on different corners of the first frame main surface so that the side faces the second substrate main surface;
A semiconductor device comprising: a control element that controls the operation of the first semiconductor switching element and the second semiconductor switching element mounted on the first substrate main surface.   A plurality of external terminals are arranged along an outer edge of the first main surface of the frame, and the first external terminal is disposed in the vicinity of the corner portion on one side of two sides adjacent to the corner portion. The terminal of the second semiconductor switching element is electrically connected, and the terminal of the second semiconductor switching element is electrically connected to the external terminal disposed in the vicinity of the corner portion on the other side. The semiconductor device according to claim 1.   3. The semiconductor according to claim 2, wherein the first frame main surface is rectangular in plan view, and the external terminals are arranged along four sides of an outer edge of the first frame main surface. apparatus.   4. The device according to claim 2, wherein at least one of the first semiconductor switching element and the second semiconductor switching element is electrically connected to the external terminal via a lead wire. 5. Semiconductor device.   At least one of the first semiconductor switching element and the second semiconductor switching element is electrically connected to the external terminal through a plate clip lead having conductivity. Item 4. The semiconductor device according to Item 2 or 3.   6. The semiconductor element unit is supported by the support substrate by a convex support portion formed on the second substrate main surface of the support substrate. A semiconductor device according to 1.   An internal lead for electrically connecting the terminal of the control element and the external terminal mounted on a corner portion of the first frame main surface where the semiconductor element unit is not disposed is provided. The semiconductor device according to claim 1, further comprising a formed conversion substrate.   The semiconductor according to any one of claims 1 to 7, wherein the first semiconductor switching element and the second semiconductor switching element are stacked via a conductive heat sink. apparatus.   The support substrate, the semiconductor element unit, and the control element are molded and sealed with a sealing body, and the second frame main surface of the frame is exposed to the outside of the sealing body. Item 9. The semiconductor device according to any one of Items 1 to 8.   10. The control device according to claim 1, wherein the control element controls the first semiconductor switching element and the second semiconductor switching element to alternately turn on and off. 11. Semiconductor device.   The semiconductor device according to claim 1, wherein the semiconductor device has three semiconductor element units, and each of the semiconductor element units controls each phase output of a three-phase motor.

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