EP3380821A1

EP3380821A1 - Semiconductor component comprising a first temperature measuring element and method for determining a current flowing through a semiconductor component

Info

Publication number: EP3380821A1
Application number: EP16777676.4A
Authority: EP
Inventors: Joachim Joos; Walter Von Emden
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2015-11-26
Filing date: 2016-10-05
Publication date: 2018-10-03
Also published as: TW201723447A; JP6824271B2; WO2017089018A1; TWI721045B; CN108291843B; DE102015223470A1; CN108291843A; JP2018536858A

Abstract

A semiconductor component (10) comprising a substrate and at least two temperature measuring elements (20, 22) is described. The two temperature measuring elements (20, 22) are arranged on the bare die (11) of the semiconductor component (10) at different positions within the semiconductor component (10). In particular, one temperature measuring element (20) can be arranged in an active region (14) and one temperature measuring element (22) can be arranged in a passive region (16) of the semiconductor component (10). The temperature measuring elements (20, 22) measure two different temperatures T_j, T_sense, with the aid of which the current IDS through the semiconductor component (10) can then be calculated. The semiconductor component may be a power MOSFET (18). Furthermore, a method for determining a current IDS flowing through a semiconductor component (10) is described, wherein two temperatures measured at different locations of the semiconductor component (10) are used. The semiconductor component (10) described and the method described are suitable for example for use in a control unit for a vehicle.

Description

description

title

SEMICONDUCTOR ELEMENT WITH A FIRST

TEMPERATURE MEASURING ELEMENT AND METHOD FOR DETERMINING A FLOW THROUGH A SEMICONDUCTOR COMPONENT

The present invention relates to a semiconductor device, preferably a power MOSFET element, and a method for producing a

Semiconductor device and a control device for a vehicle.

State of the art

The demands on modern semiconductor switches such as PowerMOSFETs (Metal Oxide Semiconductor Field Effect Transistor) and IGBT (Insulated Gate Bipolar Transistor) include, in addition to very low transmission and switching losses as well as high blocking capability more and more monolithic integrated functions that make overuse such as ESD pulses (Electrostatic Discharge, Electrostatic Discharge), overtemperature, breakthrough or overcurrent safely detectable. In power electronic systems, for example for motor control, the phase current is of crucial importance for controlling the system. Too high a current during the

Switching operation can lead to the breakdown of the element and possibly to its destruction. In many cases, therefore, the current is measured for example by a shunt or a magnetic sensor. This is complicated and expensive. If the phase current is measured by means of a shunt, additional area on the DBC (Direct Bonded Copper) or on the

Punching grid required. Furthermore, another component is needed with the shunt or magnetic sensor, which also causes costs. Alternatively, it is possible to measure the phase current internally in the device by means of separated cell areas. Here too, however, at least one external resistor and an external, often analog, evaluation circuit are necessary.

DE 10 2011 001 185 A1 describes a method for current measurement by means of the measurement of the drain-source voltage. The temperature of the barrier layer is determined and calculated from this the temperature-dependent resistor RDS _OP , from which in turn the current can be calculated.

US 2007/00061099 A1 also describes a method for determining the phase current with the aid of the drain-source voltage and a temperature. A thermistor located near a FET (Field Effect Transistor) provides a temperature from which, along with the drain-source voltage from a processor, the phase current is estimated. This is done on the assumption that the temperature difference between the thermistor and the junction of the FET in the steady state is constant.

US 201 1/021071 1 A1 describes a possibility of having the processes within a semiconductor component modeled by a processor in order to be able to carry out an evaluation of the state of the component and, if appropriate, a control of the component. For this purpose, an example supplied by a thermistor temperature, the drain-source voltage and the gate-source voltage are used as input parameters.

Disclosure of the invention

According to the invention, a semiconductor component with a substrate and a first temperature measuring element is provided, in which the first temperature measuring element is located in the vicinity of a location of high power loss of the first

Semiconductor device is arranged, and in which a second

Temperature measuring element spatially spaced from the first

Temperature measuring element is arranged on the substrate. The

Semiconductor device may be, for example, a MOSFET, an IGBT or other power semiconductor. The substrate may be a semiconductor substrate, For example, be silicon, another semiconductor substrate or a silicon-on-insulator (SOI) substrate.

A location of high power loss is understood to be a location on the semiconductor chip at which a high power loss drops during operation, in particular in the switched-through state, and which therefore heats up more than its surroundings. The term "high power dissipation" is to be interpreted in particular relative to other locations on the chip, Preferably, the first temperature measuring element is arranged in the vicinity of the location of the greatest power loss, for example in the vicinity of the exclusion zone the smallest or smallest possible power loss, as is technically possible, without influencing the function of the individual elements For example, the first temperature measuring element can be directly adjacent to the blocking zone of the semiconductor component.

The inventive method for determining a by a

Semiconductor component flowing current basically includes the following steps:

a) reading out the value of one of a high range

Power dissipation arranged first temperature measuring element supplied first temperature

b) reading the value of a second temperature supplied by a second temperature sensing element spaced from the first temperature element

c) calculating the current through the semiconductor device under

Inclusion of the first temperature and the second temperature.

An inventive control device for a vehicle comprises at least one inventive semiconductor device. Advantages of the invention

The semiconductor device according to the invention has the advantage that only a few additional elements are necessary to make a sufficiently accurate statement about the current flow through the semiconductor device. to

Evaluation can be used only the logic and the AD converter of the system ASIC (application specific integrated circuit), so again only a few additional components over conventional semiconductor devices without the

Current sensing according to the invention are necessary.

Furthermore, with the aid of the semiconductor component according to the invention and the method according to the invention it is possible to determine the phase current through the component, without including the drain-source voltage as output value. Instead, the respective local temperatures are measured at two different points of the semiconductor component, whereby, with knowledge of the thermal resistance and the thermal capacity between the two measuring points, the current power loss of the semiconductor device is measured

Can be closed, so that with the help of the resistor DS _OP, the current can be determined by the component. It can be such a

Set up overcurrent limiting for the safe switching of power electronic components such as MOSFETs or IGBTs.

The first temperature measuring element can with the second

Temperature measuring element be thermally coupled. In a special

Embodiment is provided, that the first temperature measuring element and the second temperature measuring element each comprises a diode. A measure of the temperature can in each case the falling over the respective diode

Be tension. In this way, the temperature can be determined with a small design effort for the temperature measuring elements. This saves installation space, power loss and costs for external components and, with appropriate design, can improve the response time and accuracy of current monitoring.

According to a preferred embodiment of the invention it is provided that the first temperature measuring element and the second temperature measuring element monolithically integrated into the semiconductor device. By this measure, the cost of commissioning the semiconductor device can be reduced, which also reduces the effective cost. Less individual components are needed. Since the required functions can be integrated with little effort into known semiconductor components, the overall result is a significant cost savings. A smaller number of

In addition, individual components means a smaller number of possible sources of error.

In a development of the invention, the semiconductor component comprises a third temperature measuring element. An additional fourth temperature measuring element or even more temperature measuring elements are also possible. By the

Inclusion of further temperature measuring elements, the accuracy of the current determination can be increased. The other temperature measuring elements can be monolithically integrated into the chip. All temperature measuring elements can be realized for example as a planar polysilicon diode. In principle, however, are any combinations of different

Temperature measuring conceivable to implement the invention. Likewise, the simultaneous use of monolithic integrated and external temperature measuring elements, such as thermistors, is possible. Due to the manufacturing advantages, however, are all preferred

Temperature measuring elements monolithically integrated.

In a further preferred embodiment of the invention, a finite thermal capacitance and a finite thermal resistance exist between the first temperature measuring element and the second temperature measuring element. The current power loss in the semiconductor device can then be determined relatively accurately if the first temperature and the second temperature are used as input variables for the calculation.

In one development of the invention, the semiconductor component has at least one active region and at least one passive region, the second temperature-measuring element being arranged in the passive region. In the passive region, the temperature is regularly lower than in the active region and in particular significantly lower than in the region of greatest power loss. A larger temperature difference between the two of the first Temperature measuring element and the second temperature measuring element detected temperatures increases the signal-to-noise ratio and thus improves the accuracy of the determined value for the current.

In a preferred embodiment of the invention, the

Semiconductor device is a MOSFET and one of the temperature sensing elements to be the body diode of this MOSFET. A MOSFET is particularly well suited to the formation of a power semiconductor device, such as a

Circuit breaker. If the body diode of the MOSFET is used as one of the l o temperature measuring elements, the number of drops to

Implementation of the invention necessary additional elements, since such a body diode is inherently present in each MOSFET.

In an advantageous development of the invention, it is provided that a first temperature measuring voltage across the first temperature measuring element and / or a second temperature measuring voltage across the second

Temperature measuring element can be removed in each case via dedicated pads. In other words, the relevant points in the circuit for the measurement of the two temperature measuring voltages from the outside

20 contact. Such an embodiment has the advantage that the structure can be connected flexibly from the outside further. Furthermore, the voltage required for determining the temperature can thus be measured in a simple manner, for example by connecting the pads to an evaluation circuit such as, for example, the system ASIC.

25

In a particular embodiment, the first temperature measuring element and the second temperature measuring element are connected in series. The two

Temperature measuring elements can then be fed by a common power source and flowed through by the same current. The optionally existing further temperature measuring elements can be connected in series with the first and second temperature measuring element and energized with a single sense current.

Alternatively, it is possible for the first temperature measuring element and the second temperature measuring element to be connected in parallel. For carrying out the invention, particularly fast and accurate diodes, which are ideally matched very well by their flux voltage variation over temperature, are advantageous. Due to the relatively small thermal resistances and thermal capacities between hotspot, so the place big

or the largest power loss on the chip, and the chip edge or any other location within the passive area, resulting in very good signal-to-noise ratios and little impact of

Temperature variation in the fluctuations inferior other layers such as solder, voids, DBC (direct bonded copper) or adhesive.

The inventive method is suitable to the current temperature, power dissipation and current values of a circuit breaker and

To determine control variables to avoid accelerated aging or destruction of the device.

Advantageous developments of the invention are specified in the subclaims and described in the description.

drawings

Embodiments of the invention will be explained in more detail with reference to the drawings and the description below. Show it:

Figure 1 shows a way to determine the current through a

Semiconductor device according to the prior art,

FIG. 2 shows a schematic representation of an exemplary embodiment of a semiconductor component according to the invention, FIG. 3 shows a plan view of the exemplary embodiment according to FIG. 2,

FIG. 4 shows a side view of the exemplary embodiment according to FIG. 2,

FIG. 5 shows a first embodiment of the wiring of a semiconductor component according to the invention, FIG. 6 shows a second embodiment of the circuit of a semiconductor component according to the invention,

FIG. 7 shows a third embodiment of the wiring of a semiconductor component according to the invention,

FIG. 8 shows a thermal equivalent circuit of an embodiment of the invention

9 shows a representation of exemplary measurement results, and

FIG. 10 shows a representation of a possible integration of a semiconductor component according to the invention into a circuit system.

Embodiments of the invention

1 shows a possibility for determining the current through a semiconductor component 10 in the form of a current sensor with divided cells according to the prior art. In the right part of the figure, the main

FET (field effect transistor) 2 shown. As usual, it is connected to a source contact 3, a drain contact 4 and a gate contact 5. In the left part of the figure, the measuring FET 6 is shown. This is connected in parallel to the main FET 1 and consists of a few divided, but otherwise identical to the cells of the main FETs 1 cells. The cleaved cells serve as

Current mirror. By means of the external resistor 7, a current Isense can be read out at the current measuring point 8, which allows direct conclusions to be drawn about the current flowing through the main FET 1. The resistor 7, however, can limit the dynamics and accuracy of the current measurement. In addition, in the known from the prior art solutions often

Temperature sensor and a current sensor used together to allow monitoring, which in turn leads to a relatively high

constructive and tax technical effort leads. FIG. 2 schematically shows the bare die 1 1 of a semiconductor component 10 in FIG

Form of a circuit breaker, such as a MOSFET. This includes both active surfaces 14, so in which the optionally, microscopically small switching elements are placed and in which the electrical power loss arises as well as passive areas 16, which are inactive and thus without power loss. The passive areas 16 may be, for example, bond pad areas, edge areas of the component 10 or gate runners. In each of the said passive regions 16, the second current measuring element 22 may be arranged.

FIG. 3 shows the semiconductor component from FIG. 2 in plan view. On the bare 11, two temperature measuring elements 20, 22 are arranged. These

So-called temperature-sensing structures are placed such that the first temperature sensing element 20 is disposed in the active region 14 or at least very close to the active region 14. The second

Temperature measuring element 22 is located in a certain spatial

Distance from the first temperature measuring element, for example in

Edge region 18 of the component. In the active region 14, the power loss is higher than in the passive region 16. Preferably, the first

Temperature sensing element 20 may be located close to the blocking zone of the semiconductor device 10, since the power loss is particularly high. A large temperature difference between the temperatures measured by the first temperature sensing element 20 and the second temperature sensing element 22 is desirable to improve the signal-to-noise ratio.

Figure 4 shows the embodiment of Figures 2 and 3 in a side sectional view. It can be seen the substrate 12, in which the other

Structures are incorporated. In addition, the substructure consisting of several layers 40, 42, 44 and 46 is shown.

The temperature measuring elements 20, 22 can be electrically connected in different ways. FIG. 5 shows a first possibility of interconnection of the semiconductor component 10 according to the invention. The known connections for source 30, drain 32 and gate 34 can be seen. The first diode 20, which serves as the first temperature measuring element, and the second diode 22, which serve as the second temperature measuring element serves, are connected in series. Both diodes 20, 22 are traversed by a time-constant current nse, the

for example, can be provided by the ASIC 70. The voltage drops UDI and UD2 are proportional to the respective local temperature in the region of the first diode 20 and the second diode 22, respectively.

FIG. 6 shows a second possibility of the interconnection of the semiconductor component 10 according to the invention. The first diode 20 and the second diode 22 are connected in parallel. They are powered by a first current source 26 and a second current source 27 with power.

In Figure 7, an embodiment is shown, in which as the second diode, the body diode 24 of the power MOSFET 18 used for

Temperature measurement is used.

Figure 8 shows a thermal equivalent circuit in the form of an equivalent Foster network of an embodiment of the invention. The thermal behavior of one embodiment of the invention as MOSFETs on DBC (Direct Bonded Copper) or punched grid can thus be described. The first

Temperature measuring element in the form of the first diode 20 measures the temperature Tj at the first node 50. Tj here stands for Tj _Un ction, ie the temperature in the region of the barrier layer, which often corresponds to the region of greatest power loss on the semiconductor device 10. The second diode 22, however, measures the temperature Tisense at the second node 52. Because of the spatially different arrangement to the power loss source 54 on the chip lie between two nodes 50, 52 finite thermal Wests 56 and thermal capacitances 58. It usually results in a lower temperature Tisense as the temperature Tj. In the right part of the figure, the termination of the network at room temperature T is shown _{on the} bient.

With knowledge of the two temperatures Tj and Tisense the

Temperature difference .DELTA.Τ between the two nodes 50, 52 are determined. Exemplary performed measurement series are shown in Figure 9. In each case, the thermal resistance between the nodes 50, 52 and the housing was determined. The data points plotted as circular symbols originate from the measurement Z _t h (t) j _U nction-case, ie the time-dependent thermal resistance between the first node 50 and the housing. Accordingly, the values for Zth (t) T _se nse-case, ie the thermal resistance between the second node 52 and the housing, are shown as squares. The third curve shows the difference between the two traces in the form of triangular symbols. The solid lines show corresponding fits in the Foster model with 7 RC elements each for the two measurement curves or with 2 RC elements for the difference curve. The description of

Curves in the Foster model allow a simulation of the temporal thermal behavior in the ASIC.

It can be seen that in the steady state, ie after about 50 to 1 00 ms, the difference curve is substantially horizontal, the difference between the two thermal resistance values Z _t h (t) j _U nction-case and Zth (t) T _S ense-Case alSO remains almost constant. Means ΔΤ and the now constant over time AEZ _t h = Z _t h (t) junction-case - Z _t h (t) T _S ense-case can now be according to the formula

P (t) = - ^ = / ² - R (7}) (1) calculate the current power dissipation in the die. Since the electrical Wderstand RDS _{OP of} the device in the on and steady state, for example, with the formula

(a \ ^T J- ²⁵ ° ^C

Ron {Tj) = RDSon, 2S ° C ^' [1 + (2), where a ~ 0.4 can be calculated using the formula

AT (t)

/ (t) =

lon (Tj) I ^z thJ-TS ^'R on ( ^T j) the current current can be determined. All of the calculations mentioned can be made, for example, in the possibly already existing ASIC.

A possible construction of such an ASIC is schematically in FIG. 10

shown. The ASIC 70 may initially provide a constant current nse for the two current measuring elements 20, 22. In the calculation elements 72, 74 are then first the two Flussspannungs signals UDI, UD2 of the temperature measuring elements 20, 22, which in turn formed in the form of diodes can be in terms of temperature T _se nse, Tj converted. If appropriate, a corresponding characteristic linearization can be provided beforehand for this purpose.

To determine the temperature difference, a difference ΔΤ is then formed in the differentiation module 76. Knowing the temperature Tj, the current resistance R _on (Tj) is then estimated via the above equation (2).

Furthermore, the thermal behavior of the thermal differential resistance Zthj-Tsense has been previously determined by measurement or simulation and has been firmly stored in the ASIC, for example as a two-link Foster network or as Table 78. This is sufficiently accurate, since the value for Z _t hj- T _se nse only derived from firmly arranged on the chip elements and therefore no scattering can be expected by the construction and connection technology. The current drain current is then determined from the input variables ÄT (t), R _on (Tj) and Z _t hj-T _se nse by means of the equation given above and serves as the control or monitoring variable of the circuit breaker. As a further control and / or monitoring variable, for example, the temperature Tj (t) can be used.

The invention can be used in particular for control devices for vehicles, for example for the steering of a vehicle. Also possible is an insert for power modules for hybrid or electric vehicles as well

"Self-locking" MOSFETs A variety of other applications for power MOSFETs and IGBTs are also conceivable.

Claims

claims

Semiconductor component (10) having a substrate (12) and a first temperature measuring element (20), characterized in that the first temperature measuring element (20) is disposed in the vicinity of a location of high power dissipation of the semiconductor device (10), and in that a second temperature measuring element (22 ) spaced apart from the first temperature sensing element (20) on the substrate (12) is arranged.

Semiconductor component (10) according to claim 1, characterized in that the first temperature measuring element (20) and the second

Temperature measuring element (22) each comprises a diode.

Semiconductor component (10) according to one of the preceding claims, characterized in that the first temperature measuring element (20) and the second temperature measuring element (22) monolithically into the

Semiconductor component (10) are integrated.

Semiconductor component (10) according to one of the preceding claims, characterized in that between the first

Temperature measuring element (20) and the second temperature measuring element (22) have a finite thermal capacity (58) and a finite thermal (56) resistance.

Semiconductor component (10) according to one of the preceding claims, characterized in that the semiconductor component (10) has at least one active region (14) and at least one passive region (16), wherein the second temperature measurement element (22) in the passive region (16). is arranged.

6. The semiconductor device (10) according to any one of the preceding claims, characterized in that the semiconductor device (10) is a MOSFET and that one of the temperature measuring elements (20, 22) is the body diode (24) of the MOSFET.

7. Semiconductor component (10) according to one of the preceding claims,

characterized in that a first temperature measuring voltage (UDI) across the first temperature measuring element (20) and / or a second

Temperature measuring voltage (UD2) on the second temperature measuring element (22) can be removed in each case via dedicated pads.

8. Semiconductor component (10) according to one of the preceding claims,

characterized in that the first temperature measuring element (20) and the second temperature measuring element (22) are connected in series.

9. Method for Determining a By a Semiconductor Device (10)

flowing stream, with the steps:

a) reading out the value of one of a high range

Power dissipation arranged first temperature measuring element (20) supplied first temperature (Tj)

b) reading out the value of one of the first

Temperature element (20) spatially spaced second

Temperature measuring element (22) supplied second temperature

(Tsense)

c) calculating the current through the semiconductor device (10) under

Inclusion of the first temperature (Tj) and the second

Temperature (T _se nse).

10. Control device for a vehicle, comprising at least one

Semiconductor component (10) according to one of Claims 1 to 8.