TWI721045B - Semiconductor component comprising a substrate and a first temperature measuring element, and method for determining a current flowing through a semiconductor component, and control unit for a vehicle - Google Patents

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) 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 I_DS through the semiconductor component (10) can then be calculated. The semiconductor component can be a power MOSFET.

Furthermore, a method for determining a current I_DS 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

Semiconductor component including a substrate and a first temperature measuring element, method for measuring current flowing through a semiconductor component, and vehicle control unit

The present invention relates to a semiconductor component, preferably, a power MOSFET element; and relates to a method of producing a semiconductor component and a control unit for a vehicle.

The requirements of modern semiconductor switches (for example, power MOSFETs (metal-oxide-semiconductor field effect transistors) and IGBTs (insulated gate bipolar transistors)) include ultra-low conduction state and switching loss, and high blocking capability. More and more integrated functions are formed in one piece, by which functions can reliably detect overload (for example, ESD (electrostatic discharge) pulse), over temperature, breakdown, or over current. In power electronic systems, for example, for engine control, the phase current used for the adjustment of the system is very important. Excessive high currents during the switching process can cause the device to collapse and may cause damage to the device. Therefore, in many cases, for example, the current is measured via a shunt or a magnetic sensor. This method is complicated and expensive. If the phase current is measured by a shunt, then an extra area is needed on the DBC (direct soldered copper) or on the lead frame to achieve this goal. Furthermore, using the shunt or the magnetic sensor requires another component, which also incurs costs.

Alternatively, the measurement of the phase current inside the device can also be implemented by using a separate cell body area. However, in this case, at least one external resistor and an external evaluation circuit (often an analog circuit) are needed.

DE 10 2011 001 185 A1 describes a method of current sensing by measuring the drain-source voltage. In this case, the temperature of the depletion layer is measured and the temperature-dependent resistance value R _DSon is calculated from this temperature. Then, the current current _{can be calculated from R DSon.}

US 2007/00061099 A1 also describes a method for determining the phase current by means of the drain-source voltage and a temperature. A thermistor arranged near a FET (Field Effect Transistor) provides a temperature, and a processor can predict the phase current from the temperature and the drain-source voltage. This is done under the assumption that the temperature difference between the thermistor and the depletion layer of the FET is constant in the steady state.

US 2011/0210711 A1 describes a possible way of simulating the processing in a semiconductor component by a processor, so that the state of the component can be evaluated, and therefore, the component can be controlled if appropriate. For this purpose, for example, the temperature supplied by a thermistor, the drain-source voltage, and the gate-source voltage are used as input parameters.

The present invention provides a semiconductor component, which includes a substrate and a first temperature measuring element, wherein the first temperature measuring element is arranged near a position with high power loss in the semiconductor component, and wherein a second temperature The measuring element is spatially arranged on the substrate at a distance from the first temperature measuring element. For example, the semiconductor component can be a MOSFET, an IGBT, or certain other power semiconductors. The substrate can be semiconductive The bulk substrate, for example, a silicon substrate, certain other semiconductor substrates, or a silicon-on-insulator (SOI) substrate.

In this case, the position with high power loss is understood to mean that the high power loss during the operation (specifically, in the switched-on state) in the semiconductor wafer will decrease and the temperature will therefore heat up to be greater than that. The location of the surrounding environment. In this case, it is clear that "high power loss" should be interpreted on the basis of other positions in the chip. Preferably, the first temperature measuring element is arranged near the position of the highest power loss, for example, near the depletion zone. Preferably, the spatial distance between the position with high power loss or the highest power loss and the first temperature measuring element is as small as possible. Specifically, it is technically as small as possible without affecting the uniqueness The function of the component. In other words, the first temperature measuring element is preferably located close to the position with high power loss or the highest power loss. For example, the first temperature measuring element can be directly adjacent to the depletion region of the semiconductor component.

The method for measuring the current flowing through a semiconductor component according to the present invention basically includes the following steps: a) Reading the first temperature supplied by the first temperature measuring element arranged in the area with high power loss B) read the value of the second temperature supplied by a second temperature measuring element located at a distance from the first temperature measuring element; and c) use the first temperature And the second temperature to calculate the current passing through the semiconductor component.

The control unit for a vehicle according to the present invention includes at least one semiconductor component according to the present invention.

The advantage of the semiconductor component according to the present invention is that only a few additional components are needed. The current current flowing through the semiconductor component can be stated very accurately. For the purpose of this estimation, only the logic of the system ASIC (application-specific integrated circuit) and the AD converter may be used. Therefore, compared with the conventional semiconductor components without current sensing according to the present invention, the present invention requires only a few Additional components.

Furthermore, by means of the semiconductor component according to the present invention and the method according to the present invention, the phase current flowing through the component can be measured without including the drain-source voltage as an initial value.

Instead, the temperature of these individual areas is measured at two different points of the semiconductor component. With the knowledge of the thermal resistance and thermal capacitance between the two measurement points, the current power loss of the component can be inferred. In order to make it possible to measure the current flowing through the member by means of the resistance value R _DSon. Therefore, an overcurrent limit for safe switching of power electronic components (for example, MOSFET or IGBT) can be established.

The first temperature measuring element is thermally coupled to the second temperature measuring element. In one of the special embodiments, it is assumed that the first temperature measuring element and the second temperature measuring element include a diode in each case. The temperature measurement in each case here can be the voltage dropped across the individual diode. In this way, the temperature can be measured with very low structural cost in these temperature measuring elements. Therefore, the structural space, power loss, and cost for these external components can be saved, and with an appropriate design, the response time and accuracy of the current monitoring can also be improved.

According to one of the preferred embodiments of the present invention, it is assumed that the first temperature measuring element and the second temperature measuring element are integrated into the semiconductor component in an integral manner. This measure can reduce the cost when building the semiconductor component, which also reduces the effective cost. this The measures require only a small number of unique components. Because these necessary functions can be integrated into known semiconductor components with very little expense, in general, this will result in significant cost savings. In addition, a small number of unique components means that there are a small number of possible failure sources.

In one of the developments of the present invention, the semiconductor component includes a third temperature measuring element. Similarly, there may be an additional fourth temperature measuring element, or even more temperature measuring elements. The accuracy of current measurement can be improved by incorporating another temperature measuring element. The other temperature measuring elements can also be integrated into the chip in an integrated manner. For example, although all temperature measurement elements can be realized as a planar polysilicon diode; however, in principle, any combination of different temperature measurement elements may be used to implement the present invention. Similarly, an integrated temperature measuring element and an external temperature measuring element, such as a thermistor, can also be used at the same time. However, in consideration of the advantages of production engineering, it is preferable that all the temperature measuring elements are integrated in an integrated manner.

In another preferred embodiment of the present invention, a finite thermal capacitance and a finite thermal resistance are present between the first temperature measurement element and the second temperature measurement element. If the first temperature and the second temperature are used as input variables of the calculation, the current power loss of the semiconductor component can be measured in a relatively accurate manner.

In one of the developments of the present invention, the semiconductor component has at least one active area and at least one passive area, wherein the second temperature measuring element is arranged in the passive area. The temperature in the passive zone is often lower than the temperature in the active zone, and specifically, it is significantly lower than the temperature in the zone with the highest power loss. The larger temperature difference between the two temperatures measured by the first temperature measuring element and the second temperature measuring element will increase the signal-to-noise ratio and thus improve the accuracy of the current measurement value.

In one of the preferred embodiments of the present invention, the semiconductor component can be a MOSFET, and one of the temperature measuring elements can be the body diode of the MOSFET. A MOSFET is particularly suitable for an embodiment of a power semiconductor component, for example, an embodiment of a power switch. If the body diode of the MOSFET is used as one of the temperature measuring elements, then the number of additional components required to implement the present invention will be reduced because the body diode already exists In every MOSFET.

In one of the advantageous developments of the present invention, it is assumed that the first temperature measurement voltage across the first temperature measurement element and/or the first temperature measurement voltage across the second temperature measurement element can be tapped through a dedicated contact pad in each case The second temperature measures the voltage. In other words, the location point in the circuit related to the measurement of the two temperature measurement voltages can be contacted from the outside. The advantage of this configuration is that the structure can be further interconnected in a flexible manner from the outside. Furthermore, the voltage required to determine the temperature can therefore be measured in a simple manner, for example, by a contact pad connected to an estimation circuit (for example, the system ASIC).

In one of the special embodiments, the first temperature measuring element and the second temperature measuring element are connected in series. The two temperature measuring elements will then be fed with a common current source, and the same current will flow through the temperature measuring elements. Possible further temperature measurement elements can also be connected in series with the first temperature measurement elements and the second temperature measurement elements and be powered by a single sensing current.

Alternatively, the first temperature measuring element and the second temperature measuring element may also be connected in parallel.

Particularly fast and accurate diodes will facilitate the implementation of the present invention, these diodes The forward voltage profile of is ideally matched to temperature. The relatively low thermal resistance and thermal capacitance between the hot spot (that is, the location of the chip with high power loss or the highest power loss) and the edge of the chip or certain other locations in the passive zone will result in very good thermal resistance and thermal capacitance. The signal-to-noise ratio is also minimally affected by the temperature profile in these other layers that are manipulated by flux, shrinkage, DBC (direct soldering of copper), or adhesives, etc.

The method according to the present invention is suitable for determining the current temperature, power loss, and current value of a power switch and determining the adjustment variables, so as to avoid accelerated aging or damage to the component.

The advantageous development of the present invention will be detailed in the patent attachment and explained in the description.

2: The main field effect transistor (FET)

3: Source contact

4: Drain contact

5: Gate contact

6: Measuring field effect transistor (FET)

7: resistor

8: Current measurement point

10: Semiconductor components

11: bare die

12: Substrate

14: active zone

16: passive zone

18: Edge area

20: The first temperature measuring element

22: The second temperature measuring element

24: body diode

26: First current source

27: second current source

30: Source

32: Dip pole

34: Gate

40: layer

42: layer

44: layer

46: layer

50: The first node

52: second node

54: Power loss source

58: thermal capacitance

60: thermal resistance

70: Application-specific integrated circuit (ASIC)

72: calculation element

74: Computing components

76: Differential module

78: lookup table

The exemplary embodiments of the present invention will now be explained in more detail with reference to the drawings and the following description. In the drawings: FIG. 1 shows a possible way of measuring the current flowing through a semiconductor component according to the prior art, and FIG. 2 shows a schematic diagram of one of the exemplary embodiments of a semiconductor component according to the present invention, Fig. 3 shows a plan view of an exemplary embodiment of the present invention according to Fig. 2; Fig. 4 shows a side view of an exemplary embodiment of the present invention according to Fig. 2; and Fig. 5 shows a side view of an exemplary embodiment of the present invention according to the present invention. The first embodiment of the circuit system interconnection of a semiconductor component, FIG. 6 shows the second embodiment of the circuit system interconnection of a semiconductor component according to the present invention, FIG. 7 shows a third embodiment of the circuit system interconnection of a semiconductor component according to the present invention, and FIG. 8 shows a thermal equivalent circuit diagram of one of the embodiments of the semiconductor component according to the present invention, as shown in FIG. 9 The diagram shown is the relationship diagram of exemplary measurement results, and the diagram shown in FIG. 10 is a diagram of one of the possible ways of integrating a semiconductor component according to the present invention into a circuit system.

First, FIG. 1 shows a possible way of measuring the current flowing through a semiconductor component 10 according to the prior art, which is in the form of a current sensor with a plurality of separated cells. The main FET (Field Effect Transistor) 2 is shown on the right hand side of the figure. The source contact 3, the drain contact 4, and the gate contact 5 are interconnected in a common manner. The measurement FET 6 is illustrated in the left-hand area of the figure. It is connected in parallel to the main FET 2 and is composed of several cell bodies, which are separated from the cell bodies of the main FET 2 but are completely the same. The separated cell bodies act as a current mirror. The external resistor 7 can read a current I _Sense at the current measuring point 8, and the current can be directly deduced about the current flowing through the main FET 2. However, the resistor 7 limits the dynamic range and accuracy of the current measurement. In addition, in the solutions known in the prior art, a temperature sensor and a current sensor are often used in combination to achieve the purpose of monitoring, which will result in relatively high structural and control engineering costs.

FIG. 2 schematically shows a bare die 11 of a semiconductor component 10 in the form of a power switch, for example, a MOSFET. The semiconductor component 10 includes an active region 14, that is, the region where the switching elements, which may be very small, are placed, and the There will be electrical power loss in the process; and in the passive zone 16, these zones have no effect, and therefore, there is no power loss. For example, the passive regions 16 can be solder pad regions, edge regions of the component 10, or gate runners. The second temperature measuring element 22 is arranged in each of the passive regions 16.

FIG. 3 is a plan view of the semiconductor component in FIG. 2. Two temperature measuring elements 20 and 22 are arranged on the bare die 11. These so-called temperature measurement structures are positioned such that the first temperature measurement element 20 is arranged in the active area 14 or at least very close to the active area 14. The second temperature measuring element 22 is located at a specific spatial distance from the first temperature measuring element, for example, in the edge region 18 of the member. The power loss in the active zone 14 is higher than in the passive zone 16. Preferably, the first temperature measuring element 20 can be arranged near the depletion region of the semiconductor component 10 because the power loss is particularly high. The present invention hopes that there is a large temperature difference between the temperature measured by the first temperature measuring element 20 and the temperature measured by the second temperature measuring element 22 in order to improve the signal-to-noise ratio.

Fig. 4 shows a transverse cross-sectional view of the exemplary embodiment of Figs. 2 and 3. The substrate 12 can be distinguished in the figure, and the other structures are integrated into the substrate. Furthermore, the figure also shows that the structure is composed of a plurality of layers 40, 42, 44, and 46.

The temperature measuring elements 20 and 22 can be electrically connected in various ways. The system shown in FIG. 5 is a first possible way for interconnecting semiconductor components 10 according to the present invention. The known terminals of the source 30, the drain 32, and the gate 34 can be distinguished in the figure. The first diode 20 serving as the first temperature measuring element and the second diode 22 serving as the second temperature measuring element are connected in series. _{A current I sense} that is constant over time flows through the two diodes 20 and 22. For example, the current can be provided by the ASIC 70. The voltage drops U _D1 and U _D2 are respectively proportional to the temperature of individual regions of the first diode 20 and the second diode 22.

Figure 6 shows a second possible way of interconnecting semiconductor components 10 according to the present invention. In this case, the first diode 20 and the second diode 22 are connected in parallel. In this case, they are fed by a first current source 26 and a second current source 27.

In the embodiment shown in FIG. 7, the body diode 24 of the power MOSFET is used as the second diode for temperature measurement.

The thermal equivalent circuit diagram of one embodiment of the present invention shown in FIG. 8 has an equivalent Foster network form. The thermal behavior of one of the embodiments of the MOSFET on the DBC (Direct Bonded Copper) or on the lead frame of the present invention can be described in this way. The first temperature measuring element in the form of the first diode 20 measures the temperature T _J at the first node 50. T _J here stands for T _junction , that is, it is the temperature in the region of the depletion layer (which often corresponds to the region with the highest power loss in the semiconductor component 10 ). Conversely, the second diode 22 measures the temperature T _Tsense at the second node 52. Due to the different spatial arrangement of the power loss source 54 in the chip, the finite thermal resistance 60 and the thermal capacitance 58 will appear between the two nodes 50 and 52. Under normal conditions, this will result in a temperature T _{Tsense that is lower than the temperature T J.} The right hand side of the figure illustrates the terminal of the network _{at room temperature T ambient.}

Since the two temperatures T _J and T _{Tsense are known} , the temperature difference ΔT between the two nodes 50 and 52 can be measured. For example, what is shown in FIG. 9 is the series of measurements carried out by the present invention. In this figure, the thermal resistance between nodes 50, 52 and the housing is measured in each case. The data point depicted as a circular symbol starts from the measured value Z _th (t) _{Junction-Case} , that is, it is the time-dependent thermal resistance between the first node 50 and the casing. Correspondingly, the value of Z _th (t)T _sense-Case is depicted as a square, that is, it is the thermal resistance between the second node 52 and the housing.

The third curve is the difference between the previous two measurement curves, which is depicted in the form of a triangle symbol. The solid line shows the corresponding fitting of the Foster model in each of the 7 RC elements for the two measurement curves and the 2 RC elements for the difference curve. The curve description in the Foster model can achieve the simulation results of the temporal thermal behavior in the ASIC.

It can be seen from the figure that in the steady state, that is, after about 50ms to 100ms, the interpolation curve advances substantially horizontally, that is, between the two thermal resistance values Z _th (t) _{Junction- The difference between Case} and Z _th (t)T _sense-Case remains practically constant. By △T and the current time constant △Z _th =Z _th (t) _{Junction-Case} -Z _th (t)T _sense-Case , then the current power in the die can be calculated according to the following formula loss.

因為，舉例來說，在切換為導通以及穩態之中的該構件的電阻R_DSon能夠利用下面的公式來計算：

其中，α~0.4，其可以以下面的公式為基礎來測定目前的電流。舉例來說，上面所提及的所有計算皆能夠在可能存在的任何ASIC之中被實施。

_{Because, for example, the resistance R DSon} of the member in the switch to on and steady state can be calculated using the following formula:

Among them, α~0.4, which can be used to determine the current current based on the following formula. For example, all the calculations mentioned above can be implemented in any ASIC that may exist.

A schematic diagram of one of the possible configurations of this ASIC is shown in Figure 10. The ASIC 70 will first provide a constant current I _sense for the two temperature measuring elements 20 and 22. _{In the calculation elements 72 and 74, first, the two forward voltage signals U D1} and U _{D2 of the} temperature measuring elements 20 and 22 (they are also embodied in the form of diodes) are then converted into temperature values T _sense , T _J. To achieve this, if appropriate, a corresponding characteristic curve linearization will be performed in advance.

To determine the temperature difference, a difference value ΔT is then formed in the difference module 76. Because the temperature T _{J is known , the current resistance R on} (T _J ) can then be predicted by the formula (2) mentioned above. Furthermore, the thermal behavior of the thermal differential resistance Z _thJ -T _sense has been previously measured by measurement or simulation and is permanently stored in the ASIC, for example, stored as a two-element Foster network or stored as a Look up table 78. This will be very accurate because _{the value of Z thJ-} T _sense is only inferred from the elements arranged on the chip in a fixed manner, and therefore, it is expected that there should be no variation due to construction and connection technology. Then, with the formula set forth above can be variable _{△ T (t), R on} (T J), and _Z thJ -T _sense the measured current drain I _ds from the input current, and serve as a control of the power switch and / Or monitor variables. For example, the temperature T _J (t) can also be used as another control and/or monitoring variable.

Specifically, the present invention can be used in a control unit for a vehicle, for example, for driving a vehicle. The present invention can also be used in power modules and "self-locking" MOSFETs for hybrid vehicles or electric vehicles. Similarly, many further applications for power MOSFETs and IGBTs can be designed.

10: Semiconductor components

11: bare die

14: active zone

16: passive zone

18: Edge area

20: The first temperature measuring element

22: The second temperature measuring element

Claims (9)

A semiconductor component (10), comprising a substrate (12) and a first temperature measuring element (20), characterized in that the first temperature measuring element (20) is arranged in the semiconductor component (10) with Near the location of high power loss, and it is characterized in that a second temperature measuring element (22) is spatially arranged on the substrate (12) at a distance from the first temperature measuring element (20), wherein The semiconductor component (10) has at least one active area (14) and at least one passive area (16), and the second temperature measuring element (22) is arranged in the passive area (16). The semiconductor component (10) according to the first item of the patent application, wherein each of the first temperature measuring element (20) and the second temperature measuring element (22) includes a diode. The semiconductor component (10) according to item 1 or 2 of the scope of patent application, wherein the first temperature measuring element (20) and the second temperature measuring element (22) are integrated into the semiconductor component (10) in an integral manner ) In. The semiconductor component (10) according to item 1 or 2 of the scope of patent application, wherein a finite thermal capacitance (58) and a finite thermal resistance (60) exist in the first temperature measurement element (20) and the second temperature measurement Between elements (22). The semiconductor component (10) according to item 1 or 2 of the scope of patent application, wherein the semiconductor component (10) is a MOSFET, and wherein one of the temperature measuring elements (20, 22) is the MOSFET Body diode (24). The semiconductor component (10) according to item 1 or 2 of the scope of patent application, wherein the first temperature measurement voltage (U _D1 ) and/or across the first temperature measurement element (20) is tapped through respective dedicated contact pads _{A second temperature measurement voltage (U D2} ) across the second temperature measurement element (22) is feasible. The semiconductor component (10) according to item 1 or 2 of the scope of patent application, wherein the first temperature The measuring element (20) and the second temperature measuring element (22) are connected in series. A method for measuring the current flowing through a semiconductor component (10), which includes the following steps: a) Reading the first temperature measuring element (20) provided by the first temperature measuring element (20) arranged in an area with high power loss The value of the first temperature (T _J ); b) Read the value of the second temperature (T _sense ) provided by a second temperature measuring element (22) that is spatially located At a distance from the first temperature measuring element (20); and c) using the first temperature (T _J ) and the second temperature (T _sense ) to calculate the current flowing through the semiconductor component (10), wherein The semiconductor component (10) has at least one active area (14) and at least one passive area (16), and the second temperature measuring element (22) is arranged in the passive area (16). A control unit for a carrier includes at least one semiconductor component (10) according to any one of items 1 to 7 of the scope of patent application.

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