Semiconductor arrangement with reliably switching controllable semiconductor elements

A semiconductor arrangement includes a circuit board having a metallization layer with first and second conductor tracks. The first conductor track has a base section and first, second and third sections, the third section arranged between the first and second sections. The second conductor track has first and second sections. The first section of the second conductor track is arranged between the first and third sections of the first conductor track. The second section of the second conductor track is arranged between the second and third sections of the first conductor track. The third section of the first conductor track is arranged between the first and second sections of the second conductor track. First and second subsets of semiconductor chips are arranged on the first section of the second conductor track. Third and fourth subsets of semiconductor chips are arranged on the second section of the second conductor track.

TECHNICAL FIELD

The instant disclosure relates to semiconductor arrangements having controllable semiconductor elements.

BACKGROUND

Semiconductor arrangements like power semiconductor modules or the like are widely used in automotive, industrial, and consumer electronic applications for driving loads, converting power, or the like. Typically, such a semiconductor arrangement includes at least one controllable semiconductor element, each having a first load electrode, a second load electrode, a load path formed therebetween, and a control electrode for controlling the load path. In order to achieve a high rated current, the arrangement may include two or more controllable semiconductor elements electrically connected in parallel such that their load paths are electrically connected in parallel, e.g. by electrically connecting the first load electrodes to one another, and by electrically connecting the second load electrodes to one another. Optionally, also the control electrodes may be electrically connected to one another. In the ideal case, the two or more controllable semiconductor elements electrically connected in parallel are operated synchronously by feeding a common control voltage (e.g. provided by a controller) to the individual controllable semiconductor elements using electrical lines.

Because the switching state of a controllable semiconductor element, e.g. whether the load path is electrically conducting or blocking, depends on its individual control voltage, i.e. on the difference between the electric potential of the control electrode and, e.g., the first load electrode of the corresponding controllable semiconductor element, a large current flowing through a line electrically connecting the first load electrodes can, in combination with the inevitable ohmic resistance and/or inductance of that line, lead to significantly different electric potentials at the first load electrodes of the different controllable semiconductor elements. Therefore, there may be situations in which the switching states of different controllable semiconductor elements significantly differ from each other. That is, there may be instants of time at which the load paths of some of the controllable semiconductor elements are electrically conducing, whereas the control paths of the remaining controllable semiconductor elements are electrically blocking. As a result, the electric load current through the controllable semiconductor elements having their load paths connected in parallel and, therefore, the thermal and electrical load caused by the electric load current are unevenly distributed among the controllable semiconductor elements. Hereby, the lifetime of the more heavily burdened controllable semiconductor elements may be reduced. Further, different switching states may also be caused by undesired interbody-oscillations between the controllable semiconductor elements.

The described problems are, without being restricted to, of particular interest with regard to fast switching semiconductor elements like semiconductor elements based on silicon carbide (e.g. SiC-based MOSFETs or SiC-based IGBTs) because the silicon-carbide-based semiconductor chips presently available have small foot print areas and, therefore, low rated currents so that there is a frequent requirement of electrically connecting silicon-carbide-based semiconductor chips in parallel.

There is a need for a semiconductor assembly that reduces or prevents at least one of the drawbacks that can occur when the load paths of two or more controllable semiconductor elements are operated in parallel.

SUMMARY

The semiconductor arrangement includes a circuit board comprising a metallization layer with a first conductor track and a second conductor track, and a plurality of individual semiconductor chips each comprising a controllable semiconductor element, a first load electrode, a second load electrode and a control electrode, the first load electrodes of the individual semiconductor chips electrically connected to one another, the second load electrodes of the individual semiconductor chips electrically connected to one another, and the control electrodes of the individual semiconductor chips electrically connected to one another. The first conductor track includes a base section and a first, second and third section, the third section arranged between the first and the second section, and the second conductor track includes a first and a second section. The first section of the second conductor track is arranged between the first and the third section of the first conductor track, the second section of the second conductor track is arranged between the second and the third section of the first conductor track, and the third section of the first conductor track is arranged between the first and the second section of the second conductor track. A first subset and a second subset of the plurality of semiconductor chips are arranged on the first section of the second conductor track, and a third subset and a fourth subset of the plurality of semiconductor chips are arranged on the second section of the second conductor track. The first load electrode of each of the semiconductor chips of the first and the second subset is, via at least one first electrical connection, electrically connected to the first section of the first conductor track and, via at least one second electrical connection, to the third section of the first conductor track. Further, the first load electrode of each of the semiconductor chips of the third and the fourth subset is, via at least one third electrical connection, electrically connected to the third section of the first metallization and, via at least one fourth electrical connection, to the second section of the first conductor track.

The invention may be better understood with reference to the following drawings and the description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views.

DETAILED DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings. The drawings show specific examples in which the invention may be practiced. It is to be understood that the features and principles described with respect to the various examples may be combined with each other, unless specifically noted otherwise. As well as in the claims, designations of certain elements as “first element”, “second element”, “third element” etc. are not to be understood as enumerative. Instead, such designations serve solely to address different “elements”. That is, e.g., the existence of a “third element” does not require the existence of a “first element” and a “second element”.

FIG. 1is a top view illustrating an exemplary semiconductor arrangement100,FIG. 2is a cross-sectional view of the semiconductor arrangement ofFIG. 1in a cross-sectional plane E1-E1, andFIG. 3is an electronic symbol of a controllable semiconductor element comprising a MOSFET.

Referring toFIGS. 1 and 2, the exemplary semiconductor arrangement100includes a circuit board2and a plurality (here: eight) of semiconductor chips1arranged on the circuit board2. Each of the semiconductor chips1comprises a semiconductor body10, and each semiconductor body10(and, therefore, each of the semiconductor chips1) comprises a controllable semiconductor element T.

Each semiconductor chip1includes, in addition to the semiconductor body10, a first load electrode11arranged on the semiconductor body10, a second load electrode12arranged on the semiconductor body10, and a control electrode13arranged on the semiconductor body10. Without being restricted to, the first load electrode11and the control electrode13may be arranged on that surface of the semiconductor body10facing away from the circuit board2, and the second load electrode12may be arranged on that surface of the semiconductor body10facing towards the circuit board2. Each of the controllable semiconductor elements T includes a load path integrated in the semiconductor body10between the first and second load electrodes11,12of the respective controllable semiconductor element T.

In order to control a load path of a controllable semiconductor element T, i.e. in order to control the electrical conductivity of the load path, a control voltage may be applied between the control electrode13and one of the first or second load electrodes11,12. The electrical conductivity of the load path depends on the absolute value and the polarity of the control voltage and on the design of the controllable semiconductor element T so that a desired state of the electrical conductivity of the load path (e.g. “switched ON”, i.e. load path=electrically conductive, or “switched OFF”, i.e. load path=electrically blocking) may be achieved by appropriately adjusting the control voltage.

As described above, the semiconductor body10of each of the semiconductor chips1includes an individual controllable semiconductor element T. Different controllable semiconductor elements T may be identical to each other. In this sense, “identical” may mean identical “apart from fabrication tolerances.” Examples of suitable controllable semiconductor elements T include, without being restricted to, unipolar or bipolar transistors, thyristors, or any other controllable semiconductor elements. If the controllable semiconductor elements T comprise transistors, the identical controllable semiconductor elements T may comprise, e.g., IGFETs (Insulated Gate Field Effect Transistors) like MOSFETs (Metal Oxide Semiconductor Field-Effect Transistors) or IGBTs (Insulated Gate Bipolar Transistors; e.g. reverse conducting IGBTs), or JFETs (Junction Field Effect Transistors), HEMTs (High-electron-mobility transistors), BJTs (Bipolar Junction Transistors), or any other type of transistor. Depending on the type of controllable semiconductor element T, the first load electrode11and the second load electrode12may be a source electrode and a drain electrode, or a drain electrode and a source electrode, an emitter electrode and a collector electrode, or a collector electrode and an emitter electrode, and the control electrode13may be a gate electrode or a base electrode. The principles of design and operation of such semiconductor elements T are known in the art so that no further explanations are required in this regard.

FIG. 3illustrates an electronic symbol of an exemplary controllable semiconductor element T comprising a MOSFET. As schematically illustrated inFIG. 3, a semiconductor chip1that includes a controllable semiconductor element T may optionally also include an integrated diode14which may, depending on the application, operate as freewheeling diode. If the controllable semiconductor element T comprises a MOSFET, it may include an inherent body diode which forms the integrated diode14. If the controllable semiconductor element T comprises an RC-IGBT (reverse conducing IGBT), the corresponding semiconductor chip1may include an inherent freewheeling diode that allows for reverse conducting operation and that may form the integrated diode14.

As is further illustrated inFIGS. 1 and 2, the circuit board2includes a first metallization layer21which may be attached to a dielectric layer20, and an optional second metallization layer22which may also be attached to the dielectric layer20. If there is a second metallization layer22, the dielectric layer20may be arranged between the first and second metallization layers21,22.

Each of the first and, if provided, second metallization layers21,22may consist of or include, without being restricted to, one of the following materials: copper; a copper alloy; aluminum; an aluminum alloy; any other metal or alloy that remains solid during the operation of the semiconductor assembly. According to one example, the circuit board2may be a ceramic substrate, that is, it may include a dielectric layer20which is a ceramic, e.g. a thin ceramic layer. The ceramic may, without being restricted to, consist of or include one of the following materials: aluminum oxide; aluminum nitride; zirconium oxide; silicon nitride; boron nitride; any other dielectric ceramic. For instance, the circuit board2may be, e.g., a Direct Copper Bonding (DCB) substrate, a Direct Aluminum Bonding (DAB) substrate, or an Active Metal Brazing (AMB) substrate. According to another example, the circuit board2may be a conventional printed circuit board (PCB) having a non-ceramic dielectric layer20. For instance, a non-ceramic dielectric layer20may consist of or include a cured resin. Irrespective of the materials of the first and (if provided) second metallization layers21,22and (if provided) the dielectric layer20, the circuit board2may be free of electrical connections such as, e.g., vias (via=“vertical interconnect access”) that pierce the dielectric layer20and electrically interconnect the first and second metallization layers21,22. In other embodiments however, such vias may be provided.

As is further illustrated inFIGS. 1 and 2, the first metallization layer21includes a first conductor track M1and a second conductor track M2arranged distant from one another. According to the present disclosure, a conductor track of the first metallization layer21is completely formed by material from the first metallization layer. That is, each section of such a conductor track is electrically connected to each other section of the same conductor track only by material of that conductor track, and, therefore, only by material of the first metallization layer21.

The first conductor track M1includes a base section30, a first section31, a second section32and a third section33. The third section33is arranged between the first section31and the second section32in a horizontal direction of the circuit board2. That is, when seen from above (see top view illustrated inFIG. 1) the first conductor track M1is essentially W-shaped, with the first, second and third section31,32,33forming the arms of the W and the base section30forming the base of the W. Further, the second conductor track M2includes a base section40, a first section41and a second section42. The first section41of the second conductor track M2is arranged between the first section31and the third section33of the first conductor track M1, the second section42of the second conductor track M2is arranged between the second section32and the third section33of the first conductor track M1, and the third section33of the first conductor track M1is arranged between the first section41and the second section42of the second conductor track M2, in a horizontal direction of the circuit board2. That is, when seen from above (see top view illustrated inFIG. 1) the second conductor track M2is essentially U-shaped, with the first section41and the second section42of the second conductor track M2forming the arms of the U and the base section40of the second conductor track M2forming the base of the U.

The plurality of semiconductor chips1includes at least four subsets of semiconductor chips1, wherein each of the subsets includes at least one of the plurality of semiconductor chips1, and wherein the subsets do not intersect. InFIGS. 1 and 2, the semiconductor chips1of the first subset are labelled with1-1, the semiconductor chips1of the second subset are labelled with1-2, the semiconductor chips1of the third subset are labelled with1-3, and the semiconductor chips1of the fourth subset are labelled with1-4. That is, in the example ofFIGS. 1 and 2, each of the subsets includes two of the plurality of semiconductor chips1. In general, however, each of the subsets may include at least one, at least two, at least three, . . . of the plurality of semiconductor chips1. Optionally but without being restricted to, each of the subsets may include the same number of semiconductor chips1.

As can be seen fromFIG. 1, the first subset (including the semiconductor chips1-1) and the third subset (including the semiconductor chips1-3) may be arranged in a first row RI, the second subset (including the semiconductor chips1-2) and the fourth subset (including the semiconductor chips1-4) may be arranged in a second row RII, the first subset (including the semiconductor chips1-1) and the second subset (including the semiconductor chips1-2) may be arranged in a first column CI, and the third subset (including the semiconductor chips1-3) and the fourth subset (including the semiconductor chips1-4) may be arranged in a second column CII, and the third section33of the first conductor track M1may extend between the first column CI and the second column CII. Thereby, the first and second rows RI, RII may be arranged parallel or substantially parallel to one another, the first and second columns CI and CII may be arranged parallel or substantially parallel to one another, each of the first and second rows RI, RII may be arranged perpendicular or substantially perpendicular to each of the first and second columns CI and CII, and the third section33of the first conductor track M1may be arranged parallel or substantially parallel to each of the first and second columns CI, CII.

As can also be seen fromFIG. 1, the semiconductor chips1-1of the first subset and the semiconductor chips1-2of the second subset are arranged on the first section41of the second conductor track M2, and the semiconductor chips1-3of the third subset and the semiconductor chips1-4of the fourth subset are arranged on the second section42of the second conductor track M2. As demonstrated inFIG. 2by way of example for the semiconductor chips1-2and1-4, each of the semiconductor chips1is, at its second load electrode12, electrically connected to that section of the conductor track (here: the first or second section41,42of the second conductor track M2) on which it is arranged using an electrically conductive connection layer15, e.g. a solder layer, a layer of an electrically conductive adhesive or a layer of a sintered metal powder. The first load electrode11of each of the semiconductor chips1-1,1-2of the first and second subsets is, via at least one first electrical connection W1, electrically connected to the first section31of the first conductor track M1and, via at least one second electrical connection W2, to the third section33of the first conductor track M1. Then, the first load electrode11of each of the semiconductor chips1-3,1-4of the third and fourth subsets is, via at least one third electrical connection W3, electrically connected to the third section33of the first conductor track M1and, via at least one fourth electrical connection W4, to the second section32of the first conductor track M1. That is, the first load electrode11of each of the semiconductor chips1-1,1-2of the first and second subsets is, via different electrical connections W1and W2, electrically connected to both the first and third section31,33of the first conductor track M1, and the first load electrode11of each of the semiconductor chips1-3,1-4of the third and fourth subsets is, via different electrical connections W3and W4, electrically connected to both the third and second section33,32of the first conductor track M1.

As illustrated by the example ofFIGS. 1 and 2, a first electrical connection W1and a second electrical connection W2may be formed by a single connection line51or52. Similarly, a third electrical connection W3and a fourth electrical connection W4may be formed by a single connection line51or52. It is also possible that a first electrical connection W1, a second electrical connection W2, a third electrical connection W3and a fourth electrical connection W4are formed by a single connection line51or52. Each of the mentioned electrical connections may be realized using any kind of electrical connection, e.g. a wire or a metal strip, which is, at respective points P of attachment electrically connected to the respective first load electrode11and the respective section31,32,33which it connects. InFIG. 1, the points P of attachment are schematically illustrated by bold oval dots.

A connection line51,52may be attached and thereby electrically connected at a point P of attachment to the respective first, second or third section31,32,33or to the respective first load electrode11using any suitable technology like soldering, welding, wire bonding, electrically conductively adhering and so on. In this context, wire bonding means that a wire is, at the respective point P of attachment, directly attached to and therefore directly contacts the respective first, second or third section31,32,33or the respective first load electrode11. A wire may have a circular or non-circular cross-section in sections connecting different points P of attachment. At the points P of attachment, the wire may be deformed. Wires having a non-circular, flat cross-section are often referred to as ribbons.

According to one example illustrated inFIG. 1, a single first connection line51, e.g. a single (bonding) wire or a single metal strip, may be attached and electrically connected at a first point P of attachment to the first section31of the first conductor track M1, at second points P of attachment to the first load electrodes11of one or more semiconductor chips1-1of the first subset, at a third point P of attachment to the third section33of the first conductor track M1, at fourth points P of attachment to the first load electrodes11of one or more semiconductor chips1-3of the third subset, and at a fifth point P of attachment to the second section32of the first conductor track M1. Optionally, the respective electrical connections at the first, second, third, fourth and fifth points P of attachment may be realized using the same technology, e.g. one of the technologies mentioned above.

Alternatively or additionally, a single second connection line52, e.g. a single (bonding) wire or a single metal strip, may, as illustrated inFIGS. 1 and 2, be attached and electrically connected at a first point P of attachment to the first section31of the first conductor track M1, at second points P of attachment to the first load electrodes11of one or more semiconductor chips1-2of the second subset, at a third point P of attachment to the third section33of the first conductor track M1, at fourth points P of attachment to the first load electrodes11of one or more semiconductor chips1-4of the fourth subset, and at a fifth point P of attachment to the second section32of the first conductor track M1. Optionally, the respective electrical connections at the first, second, third, fourth and fifth points P of attachment may be realized using the same technology, e.g. one of the technologies mentioned above.

According to a further option, the mentioned electrical connections at the first, second, third, fourth and fifth points P of attachment of the first connection line51and at the first, second, third, fourth and fifth points P of attachment of the second connection line52may be realized using the same technology, e.g. one of the technologies mentioned above.

According to still a further option, a single first connection line51and/or a single second connection line52may run perpendicular or substantially perpendicular to each of the first, second and third sections31,32,33of the first conductor track M1.

In any case, the load paths of the controllable semiconductor elements T integrated in the semiconductor bodies10of the semiconductor chips1of the first, second, third and fourth subsets are electrically connected in parallel because the first load electrodes11of the semiconductor chips1of the first, second, third and fourth subsets are electrically connected to one another via the first conductor track M1, and because the second load electrodes12of the semiconductor chips1of the first, second, third and fourth subsets are electrically connected to one another via the second conductor track M2.

In order to electrically interconnect the control electrodes13of each of the semiconductor chips1-1,1-2,1-3,1-4forming the first, second, third and fourth subsets, the first metallization layer21may include a third conductor track M3arranged distant from both the first and second conductor tracks M1and M2, respectively. The third conductor track M3may be an island surrounded by the third section of the first conductor track M1. As illustrated inFIG. 1, a single connection line53may be used to electrically connect the control electrodes13of each of the semiconductor chips1-1,1-3forming the first and third subsets to the third conductor track M3, and a further single connection line54may be used to electrically connect the control electrodes13of each of the semiconductor chips1-2,1-4forming the second and fourth subsets to the third conductor track M3. The connection line53is electrically connected, at points of attachment, to the control electrodes13of each of the semiconductor chips1-1,1-3forming the first and third subsets, and to the third conductor track M3. Accordingly, the connection line54is electrically connected, at points of attachment, to the control electrodes13of each of the semiconductor chips1-2,1-4forming the second and fourth subsets, and to the third conductor track M3. InFIG. 1, the points of attachment at which the connection lines53and54are attached and electrically connected to the respective control electrodes13and to the third conductor track M3, are schematically illustrated by non-bold oval dots. The technologies for producing the respective electrical connections at these points of attachment may be the same as mentioned above.

Switching the controllable semiconductor elements T synchronously may be achieved by a control voltage that is provided to the semiconductor arrangement100and evenly distributed among the controllable semiconductor elements T included in the semiconductor chips1. The control voltage is the difference between a control potential which is, via the third conductor track M3and the connection lines53and54, provided to the control electrodes13of the semiconductor chips1, and a reference potential which is, via the first conductor track M1and (at least) one of the first, second, third or fourth electrical connections W1, W2, W3, W4(e.g. one of the conductor lines51or52), provided to the first load electrodes11. The control potential may be provided to the third conductor track M3via a control potential terminal71which is mounted on and electrically connected to the third conductor track M3. For instance, the control potential terminal71may be a pin that is pressed into a sleeve mounted on (e.g. soldered to) the third conductor track M3. Similarly, the reference potential may be provided to the first conductor track M1via at least one reference potential terminal72which is mounted on and electrically connected to the third section33of the first conductor track M1. For instance, each reference potential terminal72may be a pin that is pressed into a sleeve mounted on (e.g. soldered to) the third section33of the first conductor track M1. As illustrated inFIGS. 1 and 2, there may be one control potential terminal71arranged between two reference potential terminals72. Alternatively, one of the reference potential terminals72may be omitted.

Using two reference potential terminals72makes it possible that the electrical paths between a first one of the reference potential terminals72(e.g. the left one inFIGS. 1 and 2) and the first load electrode11of each of the semiconductor chips1-1,1-2of the first and second subsets (i.e., there is one such path for each of the related semiconductor chips1-1,1-2) and the electrical paths between a second one of the reference potential terminals72(e.g. the right one inFIGS. 1 and 2) and the first load electrodes11of each of the semiconductor chips1-3,1-4of the third and fourth subsets (i.e., there is one such path for each of the related semiconductor chips1-3,1-4) have substantially identical parasitic inductivities, substantially identical parasitic capacities and substantially identical parasitic resistances. In the example ofFIGS. 1 and 2, there are eight semiconductor chips1and, therefore, eight such paths having at least one of: identical or substantially identical parasitic inductivities; identical or substantially identical parasitic capacities; and identical or substantially identical parasitic resistances.

According to a further option, the electrical paths between the control potential terminal71and the control electrode13of each of the semiconductor chips1-1,1-2,1-3,1-4of the first, second, third and fourth subsets (i.e., there is one such path for each of the related semiconductor chips1-1,1-2,1-3,1-4) may have at least one of: identical or substantially identical parasitic inductivities, identical or substantially identical parasitic capacities, and identical or substantially identical parasitic resistances. In the example ofFIGS. 1 and 2, there are eight semiconductor chips1and, therefore, eight such paths having at least one of: identical or substantially identical parasitic inductivities; identical or substantially identical parasitic capacities; and identical or substantially identical parasitic resistances.

According to still a further option, for each of the semiconductor chips1-1,1-2,1-3,1-4of the first, second, third and fourth subsets there is an electrical path from a first load terminal81through the load path of the controllable semiconductor element T integrated in the corresponding semiconductor chip1-1,1-2,1-3,1-4to a second load terminal82of the arrangement100. These electrical paths may have at least one of: identical or substantially identical parasitic inductivities, identical or substantially identical parasitic capacities, and identical or substantially identical parasitic resistances. In the example ofFIGS. 1 and 2, there are eight semiconductor chips1and, therefore, eight such paths having at least one of: identical or substantially identical parasitic inductivities; identical or substantially identical parasitic capacities; and identical or substantially identical parasitic resistances.

Also shown inFIG. 1are first and second load terminals81,82of the arrangement100. The first load terminal81serves to allow for an easy electrical connection of the first load electrodes11. As illustrated, the first load terminal81may be arranged on and electrically connected to the first conductor track M1, e.g. be arranged on and electrically connected to the base section30. Analogously, the second load terminal82serves to allow for an easy electrical connection of the second load electrodes12. As illustrated, the second load terminal82may be arranged on and electrically connected to the second conductor track M2, e.g. be arranged on and electrically connected to the base section40.

Such a load terminal81,82may, without being restricted to, be e.g. a metal sheet or a metal pin or a bonding wire. Instead of a single first load terminal81and/or a single second load terminal82, multiple first load terminals81and/or multiple second load terminals82may be provided. The electrical connection between the first or the second load terminal81,82and the corresponding conductor track M1, M2may be realized using any appropriate technology like, e.g., soldering, welding, ultrasonic bonding, or electrically conductive adhering. Each of the load terminals81,82is optional.

Instead of or in addition to a load terminal81,82, one or preferably several bonding wires (connected in parallel if two or more bonding wires are provided) may be used. For instance, several first bonding wires could be wire bonded to the base section30of the first conductor track M1in order to replace or supplement the first load terminal(s)81, and/or several second bonding wires could be wire bonded to the base section40of the second conductor track M2in order to replace or supplement the second load terminal(s)82. Such first and/or second bonding wires may be used in particular for electrically connecting the first or second load electrodes11,12to a further electronic circuit that may additionally be formed on the circuit board2(which in this case needs to be enlarged in order to provide an additional area for carrying the further electronic circuit). For instance, if electrically parallelized semiconductor elements T integrated in the semiconductor chips1form a (logical) high or low side switch of a half bridge, the further circuit may include the corresponding (logical) low or high side switch of the half bridge. Such a corresponding (logical) low or high side switch may have a design analogously to the described arrangement. For instance, the logical high and low side switches may be electrically connected to one another using several (first or second) bonding wires electrically connected in parallel, or by extending one of the first or second conductor track M1, M2.

The present invention can provide for a high degree of symmetry of the parasitic inductivities, the parasitic capacities and the parasitic resistances of the electrical interconnections (e.g. the first conductor track M1, the second conductor track M2and the connection lines51,52) with which the load paths of the semiconductor chips1are connected in parallel, and of the electrical interconnections (e.g. the third conductor track M3and the connection lines53,54) with which the control electrodes13are electrically interconnected. As a result, the transmission characteristics of the electrical connections used for distributing a control voltage, which is supplied to the arrangement, among the semiconductor elements have a high degree of symmetry so that the control voltage is, on its way from a common control voltage input to the individual semiconductor elements, distorted substantially identical so that the individual semiconductor elements “see” almost the same (distorted) control voltage so that their switching behavior is substantially identical.

For example, the individual first, second, third or fourth electrical connections W1, W2, W3, W4may exhibit at least one of (substantially) identical ohmic behaviors (ohmic resistances), (substantially) identical inductive behaviors (inductivities), and (substantially) identical capacitive behaviors (capacities). This may be achieved, e.g., if the individual the first, second, third or fourth electrical connections W1, W2, W3, W4are of identical lengths, identical cross-sectional areas, and identical materials.

An electrically symmetrical design provides identical voltage and current transfers over the respective conductor tracks and connection lines so that, for example, identical synchronous voltage impulses of the control voltage provided to the circuit arrangement100via the control potential terminal71and the reference potential terminal(s)72appear at the same time and in the same shape at the end of the lines, i.e. between the first load electrode11and the control electrode13of each of the semiconductor chips1.

According to a further advantage of the layout of the present disclosure, the parasitic inductivities provide for a negative feedback. That is, if there is a significant change dl/dt of the load current I flowing through the parallelized load paths with t being the time, e.g. if the load paths are switched from an electrically conductive into an electrically blocking state, an inductive voltage caused by parasitic inductivities is fed back from the load circuit (e.g. the drain-source circuit) to the control circuit (e.g. the gate-source circuit) so that it causes the semiconductor elements T to counteract the significant change dl/dt. Such a negative feedback significantly improves the short circuit strength of the arrangement100.

The symmetrical design improves the transmission characteristics not only of the load circuit (which includes the parallelized load paths of the semiconductor elements T) but also of the control circuit of the semiconductor arrangement100.

According to a further aspect of the invention, the different partial currents flowing through the same conductor track (for instance, each partial current may be a current through the parallelized load paths of the semiconductor elements T integrated in the semiconductor chips of one of the subsets) may be balanced using through holes formed in the respective conductor track. For instance, at least one first through hole61(e.g. one first through hole61, two first through holes61, . . . ) may be formed in the first section41of the second conductor track M2between the first subset (including the semiconductor chips1-1) and the second subset (including the semiconductor chips1-2). Analogously, at least one second through hole62(e.g. one second through hole62, two second through holes62, . . . ) may be formed in the second section42of the second conductor track M2between the third subset (including the semiconductor chips1-3) and the fourth subset (including the semiconductor chips1-4). According to a further example, at least one third through hole63(e.g. one third through hole63, two third through holes63, . . . ) may be formed in the first conductor track M1in the region between the base section30and the third section33.

In the proposed design, the parallelized semiconductor chips1may be arranged within a u-shaped section of the first conductor track M1, the u-shaped section being formed by the first and second sections31,32and the base section30of the first conductor track M1.

A further advantage of the present invention is that each of the first load electrodes11may be connected via an individual current path to the same (simply or non-simply connected) first conductor track M1so that there is no requirement to provide two or more first conductor tracks M1having substantially the same potential as the first load electrodes11(e.g. the drain, source, emitter or collector potential). Analogously, each of the second load electrodes12may be mounted on and electrically connected to the same (simply or non-simply connected) second conductor track M2so that there is no requirement to provide two or more second conductor tracks M2having substantially the same potential as the second load electrodes12(e.g. the source, drain, collector or emitter potential).

A further exemplary semiconductor arrangement100according to the principles described above is illustrated inFIG. 4. The difference as compared to the semiconductor arrangement100ofFIGS. 1 and 2is that each of the (first, second, third and fourth) subsets includes just one semiconductor chip1(each including a controllable semiconductor element T), and that the number and the locations of the points P of attachment are adapted to fit with the amended number of semiconductor chips1. As in the arrangement ofFIGS. 1 and 2, the first, second, third and fourth subsets are arranged in two rows RI and RII and two columns CI and CII.

However, the present invention is not restricted to semiconductor arrangements100having the subsets arranged in two rows RI and RII and two columns CI and CII. Following the principles described with reference to the examples described above, a semiconductor arrangement100may generally have its subsets of semiconductor chips1arranged in two or more rows RI and RII and two or more columns CI and CII.

During operation of a semiconductor arrangement100of the present invention, the direction of an averaged load current I (averaged over the first and second conductor tracks M1and M2) flowing at an instant of time through the parallelized load paths, may be parallel or substantially parallel to the first, second and third section31,32,33of the first conductor track M1.

FIG. 5is a top view of a semiconductor arrangement100that includes a half bridge. The half bridge includes a low side branch LS and a high side branch HS. The design of the low side branch LS may show at least some of the features explained with reference toFIGS. 1 to 4. Insofar, reference is made to the description ofFIGS. 1 to 4. Different from the examples ofFIGS. 1, 2 and 4, the control potential terminal71and the at least one reference potential terminal72are not arranged in the middle between the first, second, third and fourth subsets. However, disposing the terminals71,72the middle between the first, second, third and fourth subsets according to the principles explained with reference toFIGS. 1, 2 and 4would also be possible.

In addition to the at least four subsets of semiconductor chips1-1,1-2,1-3,1-4, which are part of the low side branch LS, the plurality of semiconductor chips1includes at least four further subsets of semiconductor chips1-1′,1-2′,1-3′,1-4′ which are part of the high side branch HS, wherein each of the further subsets includes at least one of the plurality of semiconductor chips1, and wherein the further subsets do not intersect. In the following, elements of the high side branch HS which correspond to elements of the low side branch LS are labelled with the same reference numeral supplemented by an apostrophe (′). InFIG. 5, the semiconductor chips1of the first further subset are labelled with1-1′, the semiconductor chips1of the second further subset are labelled with1-2′, the semiconductor chips1of the third further subset are labelled with1-3′, and the semiconductor chips1of the fourth further subset are labelled with1-4′. That is, in the example ofFIG. 5, each of the further subsets includes two of the plurality of semiconductor chips1. In general, however, each of the further subsets may include at least one, at least two, at least three, . . . of the plurality of semiconductor chips1. Optionally but without being restricted to, each of the further subsets may include the same number of semiconductor chips1. Also optionally, each of the subsets and each of the further subsets may include the same number of semiconductor chips1.

As can be seen fromFIG. 5, the first further subset (including the semiconductor chips1-1′) and the third further subset (including the semiconductor chips1-3′) may be arranged in a first further row RI′, the second further subset (including the semiconductor chips1-2′) and the fourth further subset (including the semiconductor chips1-4′) may be arranged in a second further row RII′, the first further subset (including the semiconductor chips1-1′) and the second further subset (including the semiconductor chips1-2′) may be arranged in the first column CI, and the third further subset (including the semiconductor chips1-3′) and the fourth further subset (including the semiconductor chips1-4) may be arranged in the second column CII.

As can also be seen fromFIG. 5, the semiconductor chips1-1′ of the first further subset and the semiconductor chips1-2′ of the second further subset are arranged on a fourth conductor track M4, and the semiconductor chips1-3′ of the third further subset and the semiconductor chips1-4′ of the fourth further subset are arranged on a fifth conductor track M5. Both the fourth and fifth conductor track M4, M5may be parts of the first metallization layer21and spaced distant from one another and from the first, second and third conductor tracks M1, M2, M3. The first load electrode11of each of the semiconductor chips1-1′,1-2′ of the first and second further subsets is electrically connected to both a third section43and a fifth section45of the second conductor track M2. Then, the first load electrode11of each of the semiconductor chips1-3′,1-4′ of the third and fourth further subsets is electrically connected to the fifth section45and to a fourth section44of the second conductor track. That is, the first load electrode11of each of the semiconductor chips1-1′,1-2′ of the first and second further subsets is, via different electrical connections, e.g. bonding wires, electrically connected to both the third and fifth section43,45of the second conductor track M2, and the first load electrode11of each of the semiconductor chips1-3′,1-4′ of the third and fourth further subsets is, via different electrical connections, e.g. bonding wires, electrically connected to both the fifth and fourth section45,44of the second conductor track M2.

As illustrated inFIG. 5, the fourth and fifth conductor tracks M4, M5may be electrically connected via one or more electrical connections55, e.g. bonding wires, to one another. In any case, the load paths of the controllable semiconductor elements T integrated in the semiconductor bodies10of the semiconductor chips1of the first, second, third and fourth subsets are electrically connected in parallel because the first load electrodes11of the semiconductor chips1of the first, second, third and fourth subsets are electrically connected to one another via the first conductor track M1, and because the second load electrodes12of the semiconductor chips1of the first, second, third and fourth subsets are electrically connected to one another via the second conductor track M2. Therefore, the load path of the low side branch LS is formed between the first and second conductor tracks M1, M2.

Analogously, the load paths of the controllable semiconductor elements T integrated in the semiconductor bodies10of the semiconductor chips1of the first, second, third and fourth further subsets are electrically connected in parallel because the first load electrodes11of the semiconductor chips1of the first, second, third and fourth further subsets are electrically connected to one another via the second conductor track M2and via electrical connections51′,52′, and because the second load electrodes12of the semiconductor chips1of the first, second, third and fourth further subsets are electrically connected to one another via the fourth conductor track M4, the fifth conductor track M5and the at least one electrical connection55. Therefore, the load path of the high side branch HS is formed between the second conductor track M2on the one hand and the fourth and fifth conductor tracks M4, M5on the other hand.

In order to form a half bridge, the load paths of the low side branch LS and the high side branch HS are electrically connected in series between the first conductor track M1on the one hand and the fourth and fifth conductor tracks M4, M5on the other hand. The load paths of the low side branch LS and the high side branch HS are electrically connected at the second conductor track M2so that the second conductor track M2forms a circuit node of the half bridge.

In order to electrically interconnect the control electrodes13of each of the semiconductor chips1-1′,1-2′,1-3′,1-4′ forming the first, second, third and fourth further subsets, the first metallization layer21may include a further third conductor track M3′ arranged distant from both the first, second and third conductor tracks M1, M2and M3. As illustrated inFIG. 5, a single connection line53′ may be used to electrically connect the control electrodes13of each of the semiconductor chips1-1′,1-3′ forming the first and third further subsets to the further third conductor track M3′, and a further single connection line54′ may be used to electrically connect the control electrodes13of each of the semiconductor chips1-2′,1-4′ forming the second and fourth further subsets to the further third conductor track M3′. Whereas the third conductor track M3electrically interconnects the control electrodes13of the semiconductor chips1of the low side branch LS, the further third conductor track M3′ electrically interconnects the control electrodes13of the semiconductor chips1of the high side branch HS so that the semiconductor elements T integrated in the semiconductor chips1of the low side branch LS can be controlled synchronously via a control potential applied to the third conductor track M3′ and that the semiconductor elements T integrated in the semiconductor chips1of the high side branch HS can be controlled synchronously via a further control potential applied to the further third conductor track M3′ (and independently from the semiconductor elements T integrated in the semiconductor chips1of the high side branch LS).

A further control potential for controlling the controllable semiconductor elements T integrated in the semiconductor bodies10of the semiconductor chips1of the high side branch HS, i.e. for controlling the controllable semiconductor elements T integrated in the semiconductor bodies10of the semiconductor chips1of the first, second, third and fourth further subsets, may be provided to the further third conductor track M3′ via a further control potential terminal71′. In the example ofFIG. 5, the further control potential terminal71′ is mounted on and electrically connected to a sixth conductor track M6which in turn is, via an electrical connection56, e.g. a bonding wire, electrically connected to the further third conductor track M3′. Alternatively, the further control potential terminal71′ may be mounted on and electrically connected to the further third conductor track M3′ so that the sixth conductor track M6and the electrical connection56can be omitted. The design of the further control potential terminal71′ may be the same as that of the control terminal71, and it may, e.g., be pressed into a sleeve mounted on (e.g. soldered to) the conductor track (M6or M3′) on which the further control potential terminal71′ is mounted.

Similarly, a further reference potential may be provided to the second conductor track M2via at least one further reference potential terminal72′ which is mounted on and electrically connected to the second conductor track M2. For instance, each further reference potential terminal72may be a pin that is pressed into a sleeve mounted on (e.g. soldered to) the second conductor track M2.

Whereas a control voltage for controlling the semiconductor elements T integrated in the semiconductor chips1of the low side branch LS may be provided to the low side branch LS via the at least one reference potential terminal72and the control terminal71, a further control voltage for controlling the semiconductor elements T integrated in the semiconductor chips1of the high side branch HS may be provided to the high side branch HS via the at least one further reference potential terminal72′ and the further control terminal71′.

In order to provide a supply voltage, e.g. a direct current (DC) voltage, to the half bridge, a first electrical potential V1of the supply voltage may be applied to the first conductor track M1(e.g. via the first load terminal81), and a second electrical potential V2of the supply voltage may be applied to the fourth and/or fifth conductor track M4, M5(e.g. via a load terminal83mounted on and electrically connected to the respective fourth or fifth conductor track M4, M5). By switching the load path of the high side branch HS ON (i.e. into an electrically conductive state) and by switching the load path of the low side branch LS OFF (i.e. into an electrically blocking state), the second electrical potential V2is connected to the second conductor track M2. Analogously, by switching the load path of the low side branch LS ON (i.e. into an electrically conductive state) and by switching the load path of the high side branch HS OFF (i.e. into an electrically blocking state), the first electrical potential V1is connected to the fourth and fifth conductor tracks M4, M5.

Many of the above-identified advantages of the invention are based on a high degree of symmetry. For instance, there may be a first plane of symmetry S1and/or a second plane of symmetry S2to which certain constituents of the semiconductor arrangement are (arranged) mirror-symmetric(ally).

A further advantage that may be achieved using a semiconductor arrangement100according to present disclosure is an even temperature distribution among the semiconductor chips1during operation. Therefore, all semiconductor chips1experience substantially the same thermal stress.

According to a first aspect, the semiconductor chips1-1,1-2of the first and second subsets may, with regard to the first plane of symmetry S1, be arranged symmetrically to the semiconductor chips1-3,1-4of the third and fourth subsets.

According to a second aspect, the semiconductor chips1-1,1-3of the first and third subsets may, with regard to the second plane of symmetry S2, be arranged symmetrically to the semiconductor chips1-2,1-4of the second and fourth subsets.

According to a third aspect, the entirety of the connection lines51interconnecting the first load electrodes11of the semiconductor chips1-1,1-3of the first and third subsets and the first, second and third sections31,32,33of the first conductor track M1may, with regard to the second plane of symmetry S2, be arranged mirror-symmetrically to the entirety of the connection lines52interconnecting the first load electrodes11of the semiconductor chips1-2,1-4of the second and fourth subsets and the first, second and third sections31,32,33of the first conductor track M1.

According to a fourth aspect, the first conductor track M1may, with regard to the first plane of symmetry S1, be mirror-symmetric.

According to a fifth aspect, the second conductor track M2may, with regard to the first plane of symmetry S1, be mirror-symmetric.

According to a sixth aspect, one, more than one or even the entirety of the connection lines51interconnecting the first load electrodes11of the semiconductor chips1-1,1-3of the first and third subsets and the first, second and third sections31,32,33of the first conductor track M1may, with regard to the first plane of symmetry S1, be mirror-symmetric.

According to a seventh aspect, one, more than one or even the entirety of the connection lines52interconnecting the first load electrodes11of the semiconductor chips1-2,1-4of the second and fourth subsets and the first, second and third sections31,32,33of the first conductor track M1may, with regard to the first plane of symmetry S1, be mirror-symmetric.

According to an eight aspect, the first through hole61may, with regard to the first plane of symmetry S1, be arranged symmetrically to the second through hole62.

According to a ninth aspect, the first and second reference potential terminals72may, with regard to the first plane of symmetry S1, be arranged symmetrically to one another.

According to a tenth aspect, the first plane of symmetry S1and/or the second plane of symmetry S2may intersect the control potential terminal71.

The aspects mentioned above are options in each case and may be combined within a semiconductor arrangement100in any combination.