This Utility Patent Application claims priority to German Patent Application No. 10 2016 101 433.8, filed Jan. 27, 2016; which is incorporated herein by reference.
This invention relates to the technique of packaging, and in particular to the technique of packaging multiple semiconductor chips in a stacked configuration for power applications.
Semiconductor package manufacturers are constantly striving to increase the performance of their products, while decreasing their cost of manufacture. A cost intensive area in the manufacture of semiconductor devices is packaging the semiconductor chips. The semiconductor chips may be mounted on electrically conductive carriers, such as, e.g., leadframes, and electrical connections to chip electrodes and external contacts of the package have to be produced. In particular, packages having low cost electrical connections and reduced electromagnetic stray radiation are desirable.
For these and other reasons, there is a need for the present invention.
The accompanying drawings are included to provide a further understanding of embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and together with the description serve to explain principles of embodiments. Other embodiments and many of the intended advantages of embodiments will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts.
In the following detailed description, reference is made to the accompanying drawings, which form a part thereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top”, “bottom”, “front”, “back”, “upper”, “lower”, etc., is used with reference to the orientation of the Figure(s) being described. Because parts used in the various embodiments can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
It is to be understood that the features of the various exemplary embodiments described herein may be combined with each other, unless specifically noted otherwise.
As employed in this specification, the terms “coupled” and/or “connected” are not meant to mean in general that elements must be directly coupled or connected together. Intervening elements may be provided between the “coupled” or “connected” elements. However, although not restricted to that meaning, the terms “coupled” and/or “connected” may also be understood to optionally disclose an aspect in which the elements are directly coupled or connected together without intervening elements provided between the “coupled” or “connected” elements.
Semiconductor power packages containing four or more power semiconductor devices are described herein. The power semiconductor devices are arranged in at least two levels x (lower level) and y (upper level). At least two semiconductor power devices are arranged in the lower level x.
All semiconductor power devices in the package or at least a part thereof may have a vertical structure, that is to say that the semiconductor devices may be fabricated in such a way that electric currents can flow in a direction perpendicular to the main surfaces of the semiconductor chip in which the semiconductor power device(s) is (are) implemented. A semiconductor power device having a vertical structure is implemented in a semiconductor chip having electrodes on its two main surfaces, that is to say on its top side and bottom side. A semiconductor chip may contain one or more semiconductor devices, i.e. one or more semiconductor devices may be monolithically integrated in one semiconductor chip.
Vertical power semiconductor devices may, for example, be configured as MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), IGBTs (Insulated Gate Bipolar Transistors), JFETs (Junction Gate Field Effect Transistors), HEMTs (High Electron Mobility Transistors) or power bipolar transistors. By way of example, the source (emitter) electrode of a power MOSFET (IGBT) may be arranged on one main surface, while the drain (collector) electrode of the power MOSFET (IGBT) may be arranged on the other main surface. The gate electrode of the MOSFET (IGBT) may be arranged either on the main surface on which the source (emitter) of the MOSFET (IGBT) is arranged or on the main surface on which the drain (collector) of the MOSFET (IGBT) is arranged.
The power semiconductor devices referred to herein may be manufactured from specific semiconductor material such as, for example, Si, SiC, SiGe, GaAs, GaN, AlGaN, InGaAs, InAlAs, etc, and, furthermore, may contain inorganic and/or organic materials that are not semiconductors. The power semiconductor devices arranged in the package may be of different types and may be manufactured by different technologies.
Two or more semiconductor power devices (which may be monolithically integrated in one or more semiconductor chips) are mounted over and are electrically connected to an electrically conducting carrier of the package. In one embodiment, the electrically conducting carrier may be a continuous metal plate or sheet such as, e.g., a die pad of a leadframe. The metal plate or sheet may be made of any metal or metal alloy, e.g. copper or copper alloy. In other embodiments the electrically conducting carrier may, e.g., comprise a plate of ceramics coated with metal layer(s). By way of example, such electrically conducting carrier may be a metal bonded ceramics substrate, e.g. a DCB (direct copper bonded) ceramics substrate.
Furthermore, the semiconductor packages described herein may include one or more logic integrated circuit to control the power semiconductor devices. The logic integrated circuit may include one or more driver circuits to drive one or more of the power semiconductor devices. The logic integrated circuit may, e.g., be a microcontroller including, e.g., memory circuits, level shifters, etc.
The electrically conducting carrier and/or the semiconductor power chips (in which the semiconductor power devices are implemented) may at least partly be surrounded or embedded in at least one electrically insulating material. The electrically insulating material forms an encapsulation body of the package. The encapsulation body may comprise or be made of a mold material. Various techniques may be employed to form the encapsulation body of the mold material, for example compression molding, injection molding, powder molding or liquid molding. The encapsulation body may form part of the periphery of the package, i.e. may at least partly define the shape of the semiconductor package.
The electrically insulating material may comprise or be made of a thermoset material or a thermoplastic material. A thermoset material may e.g. be made on the basis of an epoxy resin. A thermoplastic material may e.g. comprise one or more materials of the group of polyetherimide (PEI), polyether-sulfone (PES) polyphenylene-sulfide (PPS) or polyamide-imide (PAI). Thermoplastic materials melt by application of pressure and heat during molding or lamination and (reversibly) harden upon cooling and pressure release.
The electrically insulating material forming the encapsulation body may comprise or be made of a polymer material. The electrically insulating material may comprise at least one of a filled or unfilled mold material, a filled or unfilled thermoplastic material, a filled or unfilled thermoset material, a filled or unfilled laminate, a fiber-reinforced laminate, a fiber-reinforced polymer laminate, and a fiber-reinforced polymer laminate with filler particles.
A variety of different types of power packages may be designed by the techniques described herein. For instance, a power package disclosed herein may comprise two half-bridge circuits each including a high side power transistor and a low side power transistor. Further, by way of example, a power package disclosed herein may comprise three or even more half-bridge circuits each including a high side power transistor and a low side power transistor.
A power package as described herein may, e.g., be configured as a multi-phase bridge. Such multi-phase bridge may be configured to be used in power supplies, e.g. power supplies for electrical motors such as, e.g. brushless DC (BLDC) motors. Multi-phase bridges as described herein may also be used as rectifiers or power converters, e.g. DC-DC power converters or AC-DC power converters.
A source or emitter (S/E) electrode 11 is arranged on the first surface 10_1 (rear side) of the source/emitter-down semiconductor power chip 10. A drain or collector (D/C) electrode 12 and a gate (G) electrode 13 are arranged on the second surface 10_2 (front side) of the source/emitter-down semiconductor power chip 10. The gate electrode 13 serves to control an electric current between the S/E electrode 11 and the D/C electrode 12. The gate electrode 13 may be used to switch the electrical current between the S/E electrode 11 and the D/C electrode 12 ON or OFF or to adjust the electrical current between the S/E electrode 11 and the D/C electrode 12 to an adjustable value between substantially 0 A (Ampere) and a maximum current that is established if the source/emitter-down semiconductor power chip 10 is turned ON.
The source/emitter-down semiconductor power chip 10 may include a number N of semiconductor power devices, with N being an integer equal to or greater than 1. In this case, the source/emitter-down semiconductor power chip 10 may have one common S/E electrode 11 shared by all semiconductor power devices, N D/C electrodes 12 (i.e. for each semiconductor power device one D/C electrode) and N gate electrodes 13 (i.e. for each semiconductor power device one gate electrode 13).
A drain or collector (D/C) electrode 21 is arranged on the first surface 20_1 (rear side) of the drain/collector-down semiconductor power chip 20. A source or emitter (S/E) electrode 22 and a gate (G) electrode 23 are arranged on the second surface 20_2 (front side) of the drain/collector-down semiconductor power chip 20. The gate electrode 23 serves to control an electric current between the D/C electrode 21 and the S/E electrode 22. The gate electrode 23 may be used to switch the electrical current between the D/C electrode 21 and the S/E electrode 22 ON or OFF or to adjust the electrical current between the D/C electrode 21 and the S/E electrode 22 to an adjustable value between substantially 0 A and a maximum current that is established if the drain/collector-down semiconductor power chip 20 is turned ON.
Similar to the source/emitter-down semiconductor power chip 10 of
In the following, semiconductor power devices placed on the mounting surface 311 will be referred to as level x (or first level) semiconductor power devices. As may be seen in
The level x first and second semiconductor power devices 320, 321 may each be formed by a source/emitter-down semiconductor power chip 10 as illustrated in
In general, if N level x semiconductor power devices 320, 321, . . . are mounted on the mounting surface 311 of the electrically conducting carrier 310, the number of source/emitter-down semiconductor power chips 10 in which the level x semiconductor power devices are implemented may range from 1 to N. In
A first connection clip 330 is mounted over the D/C electrode 12 of the level x first semiconductor power device 320 and a second connection clip 331 is mounted over the D/C electrode 12 of the level x second semiconductor power device 321. Each of the first and second connector clips 330, 331 is electrically conducting, e.g. made of a metal material. Each of the first and second connector clips 330, 331 is electrically connected to the respective D/C electrode 12 of the respective level x first or second semiconductor power device 320 and 321, respectively.
The first connection clip 330 has a mounting surface 332 opposite the clip surface connected to the D/C electrode 12 of the level x first semiconductor power device 320. Similarly, the second connection clip 331 has a mounting surface 333 opposite the surface connected to the D/C electrode 12 of the level x second semiconductor power device 321.
As illustrated in
The mounting surfaces 332, 333 of the first connection clip 330 and the second connection clip 331, respectively, may define a second level y for placing semiconductor power chips. More specifically, a level y first semiconductor power device 340 may be mounted over the mounting surface 332 of the first connection clip 330 and a level y second semiconductor power device 341 may be mounted over the mounting surface 333 of the second connection clip 331.
The level y first semiconductor power device 340 and the level y second semiconductor power device 341 may each be implemented in a source/emitter-down semiconductor power chip 10 as explained in conjunction with
The D/C electrodes 12 of the level y first and second semiconductor power devices 340, 341 may be electrically connected to each other by a connection element 350. The connection element 350 may, e.g., be a connection clip as illustrated in
More specifically, the connection element 350 may have the shape of a plate extending in a parallel direction over the second surfaces 10_2 of the source/emitter-down semiconductor power chips 10 implementing the level y first semiconductor power device 340 and the level y second semiconductor power device 341, respectively. The plate may have a bent part configured to connect the connection element 350 to an external terminal 315 of the semiconductor package 300. Similar to the external terminals 312, 313 the external terminal 315 may, e.g., be formed of a lead pad or a lead of a leadframe which also provides for the electrically conducting carrier 310. It is to be noted that the connection element 350 may also be formed by implementations other than a connection clip, e.g. by an electrically conducting ribbon or by wire bonds.
As illustrated in
Further, the external terminals Gx1, Gx2, Gy1, Gy2 may be located in the same plane as the electrically conducting carrier 310 and/or the external terminals 312, 313, 315. By way of example, the external terminals Gx1, Gx2, Gy1, Gy2 may be formed by pads or leads of a leadframe providing also for the electrically conducting carrier (as a chip pad of the leadframe) and the external terminals 312, 313, 315 (as leads or pads of the leadframe).
Referring to
Still referring to
Semiconductor power package 300 may form a 2-phase bridge. An example of a circuit diagram of a 2-phase bridge is illustrated in
In the example illustrated in
As may be understood by comparing the circuit diagram of
The external terminals 312, 313 (corresponding to nodes 412, 413 of the circuit diagram in
It is to be noted that the electrical connections between the electrically conducting carrier 310, the level x first and second semiconductor power devices 320, 321, the first and second connection clips 330, 331, the level y first and second semiconductor power devices 340, 341, and the connection element 350 may be formed by soldering, e.g. soft soldering, hard soldering, diffusion soldering, or by any other suitable connecting methods such as sintering, gluing by an electrically conducting adhesive, etc.
Further, it is to be noted that the semiconductor power package 300 may be provided with an encapsulant providing for the body of the semiconductor power package 300 and enclosing the arrangement shown in
The semiconductor power package 500 additionally comprises a level x third semiconductor power device 522, which is implemented either in the same source/emitter-down semiconductor power chip 10 as the level x first and second semiconductor power devices 320, 321 or in an individual source/emitter-down semiconductor power chip 10. The level x first, second and third semiconductor power devices 320, 321, 522 may be arranged in a row extending along dimension D1.
The level x third semiconductor power device 522 is connected to a third connection clip 532 mounted over the second surface 10_2 of the corresponding source/emitter-down semiconductor power chip 10 and connected to the D/C electrode 12 thereof. The first, second and third connection clips 330, 331 and 532 are also arranged in a row extending along dimension D1.
A level y third semiconductor power device 542 is mounted on the third connection clip 532. The level y third semiconductor power device 542 may be implemented by a source/emitter-down semiconductor power chip 10, see
As apparent in
A connection element 550 is mounted over and electrically connected to the D/C electrodes 12 of the level y first, second and third semiconductor power devices 340, 341, 542. The connection element 550 may be similar to connection element 350 (e.g. may be formed by a connection clip) and reference is made to the description above. However, in this example, the connection element 550 spans the semiconductor power package 500 in dimension D1 from one peripheral side of the semiconductor package to the opposite peripheral side thereof. Thus, the connection element 550 may extend along dimension D1 rather than along dimension D2 as shown in the example of semiconductor power package 300.
Similar to semiconductor power package 300 the output external terminals 312, 313 and an additional output external terminal 514 are arranged along the right peripheral side of the package body. In this example no external gate terminals are arranged along this side of the semiconductor power package 500. Thus, the semiconductor power package 500 may have external output terminals 312, 313, 514 exclusively arranged at the right peripheral side of the package body (extending along dimension D1), gate external terminals Gx1, Gy1, Gx2, Gy2, Gx3, Gy3 exclusively arranged at the opposite peripheral side of the package body and external terminals 315 arranged along one or two of the peripheral package sides running along dimension D2.
In the semiconductor power package 500 the high voltage external terminals (positive supply voltage at external terminal(s) 315, output phases at external terminals 312, 313, 514) are spatially separated from the low voltage external terminals Gx1, Gy1, Gx2, Gy2, Gx3, Gy3. This facilitates to provide for the required dielectric strength of the semiconductor power package 500 and may further be advantageous in view of PCB layout.
According to
In the examples of semiconductor power packages 300, 500 as illustrated in
Further, the arrangements and concepts described by way of example for semiconductor power packages 300 and 500 may be extended to multi-phase bridges having more than three half-bridges. The extension of semiconductor power packages 300 and 500 (or “hybride” power packages using some of the features of semiconductor power package 300 and some of the features of semiconductor power package 500) to N-phase bridges is evident, and reiteration of the above disclosure is omitted for the sake of brevity.
Further, semiconductor power package 700 illustrates an example in which a connection element 550 extends along dimension D1 similar to the connection element 550 of semiconductor power package 500. Further, the spatial separation of the low voltage external terminals Gx1, Gy1, Gx2, Gy2 and the high voltage external terminals 312, 313 and the positive supply voltage at electrically conducting carrier 310 is similar to semiconductor power package 500, and reference is made to the description above in order to avoid reiteration.
As drain/collector-down semiconductor power chips 20 are used in the semiconductor package 700, the correspondence of the circuit diagram of
It is to be noted that the semiconductor power package 700 may alternatively be formed in accordance with the setup of semiconductor power package 300, i.e. having a connection element 350 extending along dimension D2 and having the external terminals Gx1, Gy1, Gx2, Gy2, 312, 313, 315 arranged along the peripheral sides of the package body in accordance with the semiconductor power package 300.
The control IC 810 may comprise a number of gate drivers, e.g. 6 gate drivers in the example shown in
It is to be noted that the semiconductor power packages 300, 500 and 700 may also be equipped with a control IC 810 similar to semiconductor power package 800. However, if drain/collector-down semiconductor power chips 20 are used instead of source/emitter-down semiconductor power chips 10, the control IC 810 is electrically insulated from the electrically conducting carrier 310 by an insulating layer (not shown) extending between the electrically conducting carrier and the control IC 810.
Further, in all embodiments disclosed herein the first, second and third connection clips 330, 331, 532 and/or the connection elements 350, 550 may be equipped with through holes 830. The through holes 830 may serve as venting holes during the manufacturing process of the semiconductor power package 300, 500, 700, 800, e.g. during a solder reflow process for connecting the semiconductor chips 10 or 20 to the connection clips 330, 331, 532 and/or the connection elements 350, 550. Further, the through-holes 830 of the first, second and third connection clips 330, 331, 532 may provide for a solder exchange between the upper surface (mounting surface 332, 333) and the bottom surface of the connection clips 330, 331, 532.
Still further, in all embodiments disclosed herein electrical connections (e.g. bond wires) may be provided between external terminals of the semiconductor power package 300, 500, 700, 800 and the drain D of the low side switches LS1, LS2, LSN. These terminals may be used as voltage sense terminals for external circuitry.
Semiconductor power packages 300, 500, 700, 800 as described herein may be of particular use in automotive engineering. By way of example, the semiconductor power packages 300, 500, 700, 800 may be configured to energize (e.g. BLDC) motors used in a fuel pump, water pump or in an electrically driven turbocharger.
Semiconductor power packages 300, 500, 700, 800 as described herein may provide an output power of, e.g., 1 W to 500 W, in particular of equal to or greater than or less than 10 W, 50 W, 200 W, 200 W, 300 W or 400 W. Semiconductor power packages 300, 500, 700, 800 as described herein may provide an output current of, e.g., 0.1 A to 100 A, in particular of equal to or greater than or less than 1 A, 10 A, 30 A, 50 A, 70 A or 90 A. During operation, voltages higher or less than 5V, 10V, 50V, 100V, 200V or 500V may be applied between the nodes 401 and 402. A switching frequency of the N-bridge may be in the range from 100 Hz to 100 MHz, but may also be outside of this range.
All semiconductor power packages 300, 500, 700, 800 provide for a space optimized package layout. Further, all semiconductor power packages 300, 500, 700, 800 provide for low stray impedance and reduce parasitic energy losses, superior distribution of external terminals along the periphery of the semiconductor power packages 300, 500, 700, 800 and allow for high heat removal capability.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.
Number | Date | Country | Kind |
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10 2016 101 433.8 | Jan 2016 | DE | national |