DE10038968A1 - Circuit arrangement with at least two semiconductor bodies and a heat sink - Google Patents

Abstract

The invention relates to a circuit arrangement comprising a semiconductor switching element (T; T12, T14, T16) which is integrated in a first semiconductor body (10; 12, 14, 16) and a further semiconductor component (DD; D22, D24) connected in series , D26), which is integrated in a second semiconductor body (D22, D24, D26), the second semiconductor body (20; 22, 24, 26) being arranged on a heat sink (30; 32) and the first semiconductor body ( 10; 12, 14, 16) is arranged on the second semiconductor body (20; 22, 24, 26).

Description

The present invention relates to a circuit arrangement, which is a semiconductor switching element that is in a first half lead body is integrated, and a series connected Another semiconductor device in a second half lead body is integrated, has. The semiconductor switch ment is in particular a power transistor and that this is connected in series semiconductor device in particular another a diode.

Series circuits with power transistors and diodes are widely used in circuit technology. An example of this is a step-up switching regulator shown in FIG. 1, the task of which is to generate an at least approximately constant output voltage Vout from an input voltage Vin. A power transistor T is connected in series with a coil L to the input voltage Vin, a series circuit of a diode DD and a capacitor C being connected in parallel with the power transistor T, the diode DD and the power transistor T being connected to one another. The power transistor T is controlled by means of a control circuit IC, the current consumption of the coil L and a current flow from the coil L via the diode DD to the capacitor C being dependent on the control of the power transistor T. The diode DD prevents the capacitor C from being discharged through the power transistor T when the power transistor T is conductive.

Power transistors that are capable of voltages up to a few hundred volts and currents up to a few amps switching require cooling measures to destroy the leis tung transistor during operation due to an overhit to prevent tongue. For cooling a power transistor it is known, the semiconductor body, or the chip in which the power transistor is integrated directly on one Heatsink, which is made of a good heat-conducting material a metal, for example, is to be applied. The Leis Tung transistor is soldered to the heat sink an optimal heat-conducting connection between the half lead to reach the body and the heat sink. This results in also an electrically conductive connection between the half conductor body and the heat sink, what with certain scarf applications, or when using certain performance transistors can cause problems.

In so-called vertical transistors, a first load path connection (source connection) and a control connection (gate connection) of the power transistor are usually on a front side of the platelet-shaped semiconductor body, while the second load path connection (drain connection) faces away from the front side Rear side of the semiconductor body is located. If the semiconductor body is soldered onto the back of the heat sink, the heat sink has the same electrical potential as the drain connection of the power transistor. This leads to problems if the power transistor is used as a so-called low-side switch, as in the example according to FIG. 1, ie if the source connection of the power transistor is connected to a reference potential and if the drain connection is connected via a Load is connected to a supply potential. The potential at the drain connection changes in such applications depending on the circuit state of the power transistor. In the case of rapidly clocked power transistors, such as those used in step-up switching regulators, this results in a change in the potential at the drain connection with a high frequency and a steep slope. The heat sink, which is electrically connected to the drain connection, acts like an antenna that emits undesired high-frequency electromagnetic interference.

To solve this problem it is known to be an electrical insulating layer between the semiconductor body of the Leis device transistor and the heat sink. Indeed is thereby the assembly of the power transistor on the Heatsink relatively complex and also results from the e electrically insulating intermediate layer a not to be neglected casual additional heat resistance between the leis tung transistor and the heat sink, which is the cooling of the Power transistor deteriorated.

There are also fully insulated housings where free lying areas of the heat sink completely with a thin NEN plastic layer are overmolded to the electro prevent magnetic interference. This plastic However, layer increases the thermal resistance between the cooling body and the surrounding air, which reduces cooling is worse. In addition, this plastic coating easily damaged, which in turn leads to the delivery of a can cause electromagnetic interference.

The aim of the present invention is to provide a circuit arrangement voltage with a semiconductor switch and another half lead to provide the building element at which on simple  Cooling of the semiconductor switch to be realized is guaranteed without an electromagnetic Interference radiation is emitted and in particular the above does not have the disadvantages mentioned.

This object is achieved by a circuit arrangement according to the Features of claim 1 solved.

Thereafter, in the circuit arrangement according to the invention second semiconductor body in which the further semiconductor device ment is integrated, applied directly to the heat sink, during the first semiconductor body in which the semiconductor switching element is integrated, abge on the heat sink facing side of the second semiconductor body is applied. The invention takes advantage of that in the rows circuit of a power transistor and a diode in one Step-up switching regulators for which the present invention is particularly suitable at the connection of the diode that the Power transistor is turned away, a potential is present, which does not change or which changes only slowly. The second semiconductor body can therefore be electrically conductive with the Heatsink can be connected without giving up a electromagnetic interference comes. Between the second The semiconductor body and the heat sink are therefore not expensive insulation measures required and the second half conductor body can for example by means of usual Montagever drive to be soldered onto the heat sink. Since an elect risch conductive connection between the first semiconductor body per, or the power transistor, and the second half lead body, or the diode, is desired and required, can also the first semiconductor body using conventional assembly techniques soldered onto the second semiconductor body the. Because of the good heat transfer between the heat sink  and the second semiconductor body and between the second There is a semiconductor body and the first semiconductor body good heat transfer between the first semiconductor body and the heat sink, which ensures good cooling of the first half lead body over the second semiconductor body and the heat sink per done.

Advantageous embodiments of the invention are the subject of subclaims.

In addition to soldering the first and second semiconductor bodies and the second semiconductor body with the heat sink of course any other connection measures in the Suitable in connection with the invention, which a good Heat transfer between the semiconductor bodies and between the second semiconductor body and the heat sink and an elect rically conductive connection between these components Afford. The semiconductor body and the second semiconductor body and the heat sink can be glued together, for example become.

According to one embodiment of the invention, that on the first semiconductor body in which the semiconductor integrated switch, another semiconductor body opened is brought, in which a drive circuit for the semiconductor switch is integrated. The further semiconductor body can doing so, for example, by soldering or gluing at first Semiconductor body are applied.

According to a further embodiment of the invention is pre see that another semiconductor switch that is in one fourth semiconductor body is integrated on the heat sink is arranged. This allows a simple  Realize series connection of two semiconductor switches, whereby the diode integrated in the second semiconductor body technically parallel to the other semiconductor switches is switched and acts as a freewheeling diode for this.

The present invention will hereinafter be described with reference to embodiment tion examples explained in more detail. Show it:

Fig. 1 step-up switching regulator according to the prior art for using the circuit arrangement according to the invention;

Fig. 2 circuit arrangement according to the invention with a first semiconductor body, a second semiconductor body and a heat sink, which are arranged one above the other;

FIG. 3 shows another embodiment of an inventive circuit arrangement with a on the first semiconductor body disposed further Halbleiterkör by which includes a driving integrated circuit on;

Fig. 4 embodiment of a circuit arrangement according to the invention, in which a plurality of semiconductor bodies with further integrated semiconductor switches are arranged next to a plurality of first and second semiconductor bodies on the heat sink;

Fig. 5 equivalent electrical circuit diagram of the Schaltungsanord voltage of FIG. 4.

In the figures, unless otherwise stated, same reference numerals same parts with the same meaning.

Fig. 1 shows a so-called step-up switching regulator according to the prior art, which has a series circuit of a power device transistor T and a diode DD, a source terminal S of the power transistor T being connected to a reference potential GND, and a drain Terminal D of the power transistor T is connected to an anode terminal of the diode DD. To control the power transistor T, a control circuit IC is provided, which is connected by means of an output terminal to a gate terminal G of the power transistor T.

The drain terminal D of the power transistor T is via egg ne coil L connected to a supply potential Vin. The The cathode connection K of the diode DD is connected to a connection Capacitor C connected, the other connection to Be potential is GND. There is an off across capacitor C. output voltage Vout can be tapped. During the operation of the high set switching regulator changes the potential at the drain Terminal D of the power transistor T, or at the anode circuit A of the diode DD in accordance with a clock with which the Power transistor T is driven. The source potential of the power transistor T always remains during operation to reference potential GND. The potential at the cathode K Diode DD, which corresponds to the output potential Vout, remains largely constant or changes during operation is slow compared to the control clock.

Fig. 2 shows a side sectional view of a circuit arrangement for realizing the series circuit shown in Fig. 1 of the power transistor T and the diode DD, in which good cooling of the power transistor T is guaranteed without electromagnetic interference radiation being emitted. Corresponding connections are identified in FIGS. 1 and 2 by the same reference numerals.

The circuit arrangement according to the invention has a first semiconductor body 10 , in which the power transistor T is integrated, and a second semiconductor body 20 , in which the diode DD is integrated. Both the power transistor T and the diode DD are designed as so-called vertical components, that is, connections of a component are located on opposite surfaces of the semiconductor body. The first semiconductor body 10 has a front side 101 , on which a contact 41 for the gate connection G and a contact 11 for the source connection S of the power transistor T is formed. The second semiconductor body has a front side 201 , which forms the anode connection of the diode DD, and it has a rear side 202 , which forms the cathode connection of the diode DD. To connect the anode terminal A of the diode DD and the drain terminal D of the power transistor T, the rear side 102 of the first semiconductor body 10 is electrically conductively connected to the front side 201 of the second semiconductor body. For this purpose, an electrically conductive intermediate layer 21 is formed between these two semiconductor bodies 10 , 20 , which preferably consists of a metal, and by means of which the two semiconductor bodies 10 , 20 are connected to one another.

The second semiconductor body 20 is larger than the first semiconductor body 10 , so that the second semiconductor body 20 protrudes under the applied first semiconductor body 10 . The conductive intermediate layer 21 also protrudes from under the first semiconductor body 10 and enables the rear side 102 of the first semiconductor body 10 , or the drain terminal D of the transistor T, to be contacted via an area 42 next to the first semiconductor body 10. The conductive intermediate layer preferably covers 21 between the first and second semiconductor bodies 10 , 20 completely in front of the front side 201 of the second semiconductor body 20 .

The second semiconductor body 20 with the overlying first semiconductor body 10 is brought up to a heat sink 30 , which serves, in particular, to absorb the heat accumulating in the first semiconductor body 10 of the power transistor T and to release it to the environment. For this purpose, the heat sink 30 is preferably of substantially larger area than the first and second semiconductor bodies 10 , 20 . Between the second semiconductor body 20 and the heat sink 30 , a connection layer 31 is provided which has a low thermal resistance in order to be able to dissipate the heat from the semiconductor bodies 10 , 20 well. The connection layer 31 is preferably made of a metal, said second semiconductor body may be soldered 20 by means of the intermediate layer 31 on the heat sink 30th A contact 43 is provided on the cooling body 30 for contacting the cathode terminal of the diode DD arranged on the rear side 202 of the second semiconductor body 20 .

Problems of electromagnetic radiation via the cooling body 30 do not exist in the arrangement shown in FIG. 2, since the cathode connection K remains at least approximately at a constant potential Vout. The first semiconductor body 10 is cooled via the second semiconductor body 20 and the heat sink 30 , the heat resistances between the first semiconductor body 10 and the second semiconductor body 20 and between the second semiconductor body 20 and the heat sink 30 through the use of metallic intermediate layers 21 , 31 are low, so that good heat dissipation from the first semiconductor body 10 is ensured. Of course, in addition to metallic intermediate layers 21 , 31, any further intermediate layers can be used which have a low thermal resistance and which ensure an electrically conductive connection between the first semiconductor body 10 and the second semiconductor body 20 or between the second semiconductor body 20 and the heat sink 30 .

Fig. 3 shows a further embodiment of a circuit arrangement according to the invention, which differs from the embodiment shown in Fig. 2 in that a third semiconductor body 40 is applied to the first semiconductor body 10 , in which a control circuit IC for the in the first Integrated semiconductor circuit breaker T is integrated. A connection terminal AK of the control circuit IC is connected to the gate connection G, 41 of the first semiconductor body 10 . The third semiconductor body 40 is preferably applied to the first semiconductor body 10 by means of an electrically insulating intermediate layer 44 .

In the embodiment of FIG. 3, a metallization level 211 is applied to the front side 201 of the second semiconductor body 20 , which preferably completely covers the front side 201 . Between the rear side 102 of the first semiconductor body 10 and the metallization level 211 , an electrically conductive connection layer 212 - preferably a solder material - is formed in order to connect the rear side 102 of the first semiconductor body 10 and the front side 201 of the second semiconductor body 20 to one another in an electrically conductive manner. The metallization level 211 and the connection layer 212 form an electrically conductive intermediate layer 21 .

An adjacent to the first semiconductor body 10 loading area 42 of the metallization level 211 forms a contact D, A for the drain connection of the transistor T in the first semiconductor body 10 or for the anode of the diode DD in the second semiconductor body 20 . The drain zone arranged in the area of the rear side 102 of the first semiconductor body 10 can be contacted in a simple manner via the contact 42 . The contact 42 forms a common connection for the A node A of the diode DD and the drain D of the transistor T.

Fig. 4 shows a further embodiment of an inventive circuit arrangement in perspective presen- tation, in which a plurality of second semiconductor bodies 22 , 24 , 26 with overlying first semiconductor bodies 12 , 14 , 16 are applied to egg NEM heat sink 32 . As with the exporting approximately example of FIG. 2, each first semiconductor body, in which a vertical transistor is integrated, 12, 14, 16 well conductively connected thermally conductive and electrically connected to the respective second semiconductor body 22, 24, 26. Furthermore, every second semiconductor body 22 , 24 , 26 , in which a diode is integrated, is connected to the heat sink 32 with good heat and electrical conductivity. Fourth semiconductor bodies 52 , 54 , 56 , in which further semiconductor switches are integrated, are applied to the heat sink 32 . These semiconductor switches are also ausgebil det as vertical transistors, the rear sides of the semiconductor body 52 , 54 , 56 are electrically conductive and good heat conductor with the heat sink 32 a related party. The cathode connections of all the diodes integrated in the second semiconductor bodies 22 , 24 , 26 and the drain connections of all further power transistors integrated in the fourth semiconductor bodies 52 , 54 , 56 are at a common potential above the heat sink 32 . Source connections S52, S54, S56 and gate connections G52, G54, G56 of the further power transistors are accessible on the front sides of the fourth semiconductor bodies 52 , 54 , 56 . In addition, both source connections S12, S14, S16 and gate connections G12, G14, G16 are accessible on the front sides of the first semiconductor bodies 12 , 14 , 16 .

FIG. 5 shows the electrical equivalent circuit diagram of the circuit arrangement shown in FIG. 4. The equivalent circuit diagram has three series connections of a first power transistor T12, T14, T16 and a second power transistor T52, T54, T56, with a source connection S52, S54, S56 of a second power transistor T52, T54, T56 each connected to a drain connection of a first Power transistor T12, T14, T16 is closed. For this purpose, electrical connections 62 , 64 , 66 are shown schematically in FIG. 4, which connects the source connection S52, S54, S56 of each further power transistor to the front side of one of the second semiconductor bodies by 22 , 24 , 26 , the front side being electrical with the back of one of the first semiconductor bodies 12 , 14 , 16 and thus electrically conductively connected to a drain connection of a first power transistor T12, T14, T16. In series with the first power transistors T12, T14, T16 and thus in parallel with the second power transistors T52, T54, T56, a diode D22, D24, D26 is connected, which is integrated in the second semiconductor bodies 22 , 24 , 26 . The cathode connections K of the diodes D22, D24, D26 and the drain connections of the second power transistors T52, T54, T56 are connected to one another via the heat sink 32 .

The half-bridge circuit shown in FIGS . 4, 5 is suitable for driving motors, with additional freewheeling diodes to be connected in parallel to the first power transistors T12, T14, T16, which are shown in dashed lines in FIG. 5.

The circuit arrangement according to the invention enables on simple way to implement the series connection of a Lei tung transistor and a diode, good cooling of the Power transistor is guaranteed and in which no e Electromagnetic interference radiation abge from the heat sink is radiated without electrical insulation between the semiconductor bodies applied to the heat sink and the heat sink is required. As power transistors are any performance in connection with the invention transistors can be used, the vertical construction leads are. Particularly suitable as power transistors right MOSFET (Metal Oxide Semiconductor Field Effect Transistor) and IGBT (Insulated Gate Bipolar Transistor).  

LIST OF REFERENCE NUMBERS

A anode
AK output terminal
C capacitor
D drain connector
DD diode
D22, D24, D26 diodes
G gate connector
GND reference potential
G12, G14, G16 gate connections
G52, G54, G56 gate connections
IC control circuit
K cathode
S source connector
S12, S14, S16 source connections
S52, S54, S56 source connections
T power transistor
T12, T14, T16 first power transistor
T52, T54, T56 second power transistor
Vin input voltage
Vout output voltage

10

first semiconductor body

11

Source electrode

12

.

14

.

16

first semiconductor body

20

second semiconductor body

22

.

24

.

26

second semiconductor body

21

interlayer

211

metallization

212

link layer

30

heatsink

31

interlayer

40

third semiconductor body

41

Gate electrode

42

Drain

43

Cathode terminal

44

insulating intermediate layer

62

.

64

.

66

electrically conductive connections

101

Front of the first semiconductor body

102

Back of the first semiconductor body

201

Front of the second semiconductor body

202

Back of the second semiconductor body

Claims (11)

1. A circuit arrangement which has a semiconductor switching element (T; T12, T14, T16) which is integrated in a first semiconductor body ( 10 ; 12 , 14 , 16 ) and a further semiconductor component (DD; D22, D24, D26) connected in series ), which is integrated in a second semiconductor body (D22, D24, D26), characterized in that the second semiconductor body ( 20 ; 22 , 24 , 26 ) is arranged on a cooling body ( 30 ; 32 ) and that first ( 10 ; 12 , 14 , 16 ) semiconductor body is arranged on the second semiconductor body ( 20 ; 22 , 24 , 26 ). 2. Circuit arrangement according to claim 1, wherein the half lead terschaltelement (T; T12, T14, T16) a transistor and at which the further semiconductor component (DD; D12, D14, D16) one Is diode. 3. Circuit arrangement according to claim 1 or 2, in which a surface of the first semiconductor body ( 10 ; 12 , 14 , 16 ) facing the second semiconductor body ( 20 ; 22 , 24 , 26 ) is smaller than one surface of the first semiconductor body ( 10 ; 12 , 14 , 16 ) facing surface of the second semiconductor body ( 20 ; 22 , 24 , 26 ). 4. Circuit arrangement according to one of the preceding and workman surface, in which the second semiconductor body ( 20 ; 22 , 24 , 26 ) is soldered or glued to the heat sink ( 30 ; 32 ). 5. Circuit arrangement according to one of the preceding claims, in which the first semiconductor body ( 10 ; 12 , 14 , 16 ) is soldered or glued to the second semiconductor body ( 20 ; 22 , 24 , 26 ). 6. Circuit arrangement according to one of the preceding claims, in which a further semiconductor body ( 40 ), in which a control circuit for the semiconductor switch is integrated, is applied to the first semiconductor body ( 10 ). 7. Circuit arrangement according to one of the preceding claims, in which a further semiconductor switch (T52, T54, T56) which is integrated in a fourth semiconductor body ( 52 , 54 , 56 ) is arranged on the heat sink ( 32 ). 8. The circuit arrangement as claimed in claim 7, in which a plurality of second semiconductor bodies ( 22 , 24 , 26 ), on each of which a first semiconductor body ( 12 , 14 , 16 ) with an integrated semiconductor switch (T12, T14, T16) is arranged, and in which a plurality of fourth semiconductor bodies ( 52 , 54 , 56 ) with integrated further semiconductor switches (T52, T54, T56) are arranged on the heat sink ( 32 ). 9. Circuit arrangement according to one of the preceding claims, in which an exposed area of an electrically conductive intermediate layer ( 21 ; 211 ) on a front side 201 of the second semiconductor body 20 forms a connection for the rear side 102 of the first semiconductor body 10 . 10. Use of a circuit arrangement according to one of the vo ranked claims in a switching power supply. 11. Use of a circuit arrangement according to one of the vo ranking claims in a half-bridge circuit.