Sensor unit for an electronic device, electronic device, and method for mounting a sensor element

Abstract

According to one embodiment, a sensor unit (10) for an electronic device (100) comprises a sensor element (1) for measuring a physical quantity in the electronic device and a contact element (2) configured to be mechanically biased. A contact element is fixed to and electrically connected to the sensor element. The sensor unit is configured to be mounted to a component of the electronic device by placing the sensor element on a measurement surface of the component and by mechanically biasing the contact element such that the mechanically biased contact element exerts a direction action on the sensor element towards the measurement surface.

Description

Technical Field

[0001] The present disclosure relates to a sensor unit for an electronic device, an electronic device, and a method for mounting a sensor element. Summary of the invention

[0002] An object of the present disclosure is to provide an improved sensor unit for an electronic device, for example, a sensor unit that can be easily and securely mounted to an electronic device. Another object of the present disclosure is to provide an electronic device having such a sensor unit. Still another object of the present disclosure is to provide an improved method for mounting a sensor element, for example, a method for mounting a sensor element using the above-mentioned sensor unit.

[0003] Embodiments of the present disclosure relate to an improved sensor unit for an electronic device, an improved electronic device, and an improved method for mounting a sensor element.

[0004] First, a sensor unit for use in an electronic device is specified.

[0005] According to one embodiment, a sensor unit for an electronic device includes a sensor element for measuring a physical quantity in the electronic device and a contact element configured to be mechanically biased. The contact element is fixed to the sensor element and electrically connected thereto. The sensor unit is configured to be mounted on a component of the electronic device by placing the sensor element on a measuring surface of the component of the electronic device and by mechanically biasing the contact element, so that the mechanically biased contact element exerts a force on the sensor element that acts in a direction toward the measuring surface.

[0006] Such a sensor unit can be easily mounted on an electronic device (such as a power semiconductor module) even if the electronic device was originally developed without such a sensor element. The contact element, which can be biased to exert a force on the sensor element, enables the sensor element to be securely placed on the measuring surface without using any additional connection means (such as solder or adhesive). Instead, the biased contact element presses the contact element toward or against the measuring surface, and thereby also makes it possible to form a safe dry electrical contact between the sensor element and the measuring surface. In order to maintain the biased state of the contact element, a structure existing in the electronic device (such as a terminal or a resin housing) can be used to fix a part of the contact element thereto.

[0007] For example, a sensor element is a transducer (measured variable transducer) and is therefore part of a measuring device that directly responds to a measured variable. Thus, a sensor element can be the first element of a measuring chain. For example, a sensor element is configured to detect a physical quantity, such as temperature, humidity, pressure, acceleration, etc., and in response thereto, to generate or manipulate an electrical signal that can be read out via a contact element.

[0008] The contact element is at least partially electrically conductive. The contact element may comprise a contact region, which is a region remote from the sensor element, in particular a region opposite the sensor element, and in which the contact element may be electrically connected. The contact element provides an electrically conductive path from the sensor element to the contact region. In this way, the sensor element may be read out with the aid of the contact element, in particular an electrical signal may be received from the sensor element via the contact element or an electrical signal may be supplied to the sensor element via the contact element. Thus, the contact element may also be used to supply a voltage and / or a current to the sensor element.

[0009] The contact element can be formed as one piece or can consist of several parts. For example, the contact element is made of metal or includes metal. The contact element is configured to be mechanically biased, which means that at least a part / segment of the contact element is elastic and deformable so that the contact element enters a biased state of the contact element from a relaxed state of the contact element. In the biased state, the contact element tends to automatically return to the relaxed state. At least one elastic part of the contact element (for example) is reversibly deformable. The contact element may include one or more deformable elastic parts / segments (such as springs). In the case of causing the contact element to enter a biased state from a relaxed state, for example, at least one elastic or deformable part is compressed and / or bent and / or deflected. Mechanical bias and mechanical stress are used as synonyms.

[0010] The contact element is mechanically fixed to the sensor element. This means that the contact element and the sensor element form a composite. The connection between the contact element and the sensor element can be a form-fitting and / or force-fitting and / or material-locking (bonding) connection. For example, such a connection is not non-destructively removable. When the sensor unit is installed, it is installed together with the composite of the sensor element and the contact element. That is, the contact element and the sensor element are not installed separately.

[0011] In the case where the sensor unit is mounted on a component of an electronic device, the sensor element (e.g., its bottom side) can be placed on the measuring surface of the component. The bottom side of the sensor element (e.g.) is the side of the sensor element opposite to the side on which the connection between the contact element and the sensor element is established. Thus, the mounted sensor element can be arranged between at least a part of the contact element and the measuring surface. Here, the measuring surface of the component refers to the surface on which the physical quantity is measured by means of the sensor element.

[0012] In case of mounting the sensor unit, the contact element may be mechanically biased, i.e. brought into a biased state, so that it exerts a force on the sensor element towards the measuring surface. For example, the sensor unit is configured such that in case of taking out the sensor unit by holding and / or fixing the sensor unit at a specific area of ​​the contact element (e.g. at its end area), then placing the sensor element on the measuring surface, and attempting to push the sensor element further towards the measuring surface, the contact element is mechanically biased, i.e. at least one deformable portion of the contact element is deformed.

[0013] If the contact element is then fixed relative to the component by the measuring surface so as to maintain the biased state, the sensor element will be firmly positioned on the measuring surface without requiring a material-locked connection between the sensor element and the measuring surface, for example, where the connection between the sensor element and the measuring surface is of a merely form-fitting and / or force-fitting nature.

[0014] For example, the contact element, when biased, is configured to exert a force of at least 0.01 N or at least 0.1 N on the sensor element.

[0015] According to another embodiment, the sensor element is a temperature sensor. For example, the sensor element is a temperature sensitive resistor (also called a "thermistor"). The sensor element can be an NTC, a PTC, a platinum resistor (such as PT100 or PT1000), or a thermocouple. Alternatively, the sensor element can be a humidity sensor, an acceleration sensor, or a pressure sensor.

[0016] In fact, customers are very interested in temperature monitoring of power semiconductor devices (also referred to herein as "power semiconductor chips" or simply "chips") or power semiconductor modules during operation. Temperature monitoring is often used to protect the chip from overheating, for example in the event of an overcurrent, or to monitor the degradation state of the power semiconductor module with respect to, for example, aging of the bonding connections (which in turn affects the thermal resistance and thus the chip temperature).

[0017] According to at least one embodiment, the contact element comprises or is one of the following: a spring contact element or a pressing contact pin. The spring contact element has, for example, a meandering region and / or a V-shaped region and / or a U-shaped region and / or a spring washer region and / or a spring region, which can be compressed to bring the contact element into a biased state. Additionally or alternatively, the spring contact element can have a cantilevered portion, which can be bent to bring the spring contact element into a biased state. The spring contact element can be formed as one piece.

[0018] The push stylus comprises, for example, a body, such as a barrel or tubular body / sleeve, a tip element, such as a plunger, and one or more springs, such as one or more coil springs, which can be compressed to bring the contact element into a biased state. The tip element is movably mounted relative to the body and can be moved toward the body or further into the body by compressing the spring. The push stylus is, for example, an elongated element. The tip element of the push stylus can be fixed to the sensor element.

[0019] According to another embodiment, the contact element is fixed to the sensor element by a material-locked connection or an adhesive connection, respectively. In addition, the electrical connection can be established by a material-locked connection. For example, the contact element is welded, sintered, or glued to the sensor element, or a fixed connection is achieved by any other suitable joining method.

[0020] According to another embodiment, the contact element comprises means for screwing the contact element into a thread of the electronic device (e.g. a threaded hole of an auxiliary terminal). For example, the contact element comprises an external thread. However, alternatively, other means for fixing the contact element to the electronic device are also conceivable, such as a profile or ribs on the outer surface of the contact element, which can be embedded in the casting / resin in order to fix the contact element to the electronic device in a form-fitting manner.

[0021] According to another embodiment, the contact element comprises a terminal region, wherein the terminal region is configured to be electrically connected. When installed in an electronic device, the terminal region can be exposed so that it can be electrically contacted with the outside. The terminal region is formed, for example, by the end of the contact element away from the sensor element and / or opposite to the sensor element (for example, by the above-mentioned contact region). For example, the terminal region is formed by the longitudinal end of the pressing contact pin opposite to the pin element.

[0022] According to another embodiment, the contact element comprises a terminal structure. The terminal region may be part of the terminal structure. The terminal structure is connected, for example, to a spring contact or a press contact pin of the contact element. The terminal structure may be a sheet-like structure or a hollow cylinder with a thread (such as a nut). It may be made of metal. When installed in an electronic device, the sheet-like structure may extend substantially parallel to the main extension plane of the electronic device. For example, the terminal structure extends obliquely or perpendicularly to the main extension direction of the press contact pin.

[0023] For example, the spring contact or the pressing contact pin of the contact element is connected to the terminal structure by welding, soldering, crimping, gluing, or screwing. Alternatively, the spring contact or the pressing contact pin can be formed integrally with the terminal structure.

[0024] According to another embodiment, the sensor element comprises a top electrode at a top side of the sensor element.Furthermore, the sensor element may comprise a bottom electrode at a bottom side of the sensor element, wherein the bottom side is opposite to the top side.

[0025] The top electrode and the bottom electrode are, for example, metal areas of the sensor element. They are configured to electrically connect the sensor element for read-out and / or supply current and / or voltage to the sensor element.

[0026] According to another embodiment, the contact element is electrically connected and fixed to the top electrode of the sensor element.

[0027] According to a further embodiment, the bottom electrode of the sensor element, in particular its side facing away from the top electrode, is exposed in the unmounted configuration of the sensor unit. That is, in the unmounted configuration, the bottom electrode is freely accessible. For example, in the case of mounting on a measuring surface, a (dry) electrical contact is established between the bottom electrode and the measuring surface, so that the sensor element can be read out via the measuring surface on the one hand and via the contact element on the other hand.

[0028] Next, an electronic device is specified. The electronic device described herein may be, for example, a power semiconductor module or a component including a power semiconductor module.

[0029] According to one embodiment, the electronic device comprises a sensor unit according to any of the embodiments described herein. Furthermore, the electronic device comprises a member having a measurement surface, at which a physical quantity is to be measured by means of a sensor element. The sensor element is placed on the measurement surface. The contact element is mechanically biased so as to exert a force on the sensor element that acts in the direction of the measurement surface.

[0030] Since the electronic device includes the sensor unit according to any embodiment described herein, all features disclosed for the sensor unit are also disclosed for the electronic device, and vice versa.

[0031] The sensor element can be placed directly on the measuring surface, ie can adjoin the measuring surface. At least in this way a thermal contact between the measuring surface and the sensor element can be formed.

[0032] For example, the contact element is fixed in the electronic device so that it is kept in a biased state. For example, the contact element is fixed to prevent the contact element or any part thereof from moving in a direction away from the measuring surface and entering a relaxed state. On the other hand, since the sensor element is placed on the measuring surface, the sensor element is also prevented from moving in a direction toward the measuring surface to enter a relaxed state. The biased contact element can press the sensor element against the measuring surface. In this way, reliable contact between the measuring surface and the sensor element can be achieved. Contact loss between the sensor element and the measuring surface can be prevented. In addition, lateral movement of the sensor element also becomes difficult.

[0033] According to another embodiment, the sensor elements are placed on the measuring surface or the corresponding component, respectively, without a material-locked connection (bonding) connecting them. For example, the sensor element can be non-destructively removed from the measuring surface. For example, the sensor element is connected to the measuring surface purely by force fit and / or form fit. A non-material-locked connection between two elements is also called a "dry connection".

[0034] The sensor element can be electrically connected to the measuring surface or the component, respectively. The electrical contact between two elements established without a material-locked connection, i.e. by a dry connection, is referred to herein as a "dry electrical contact". For example, the electrical contact between the measuring surface and the sensor element is provided exclusively by a dry electrical contact.

[0035] According to another embodiment, the electronic device includes a power semiconductor device. As an example, the power semiconductor device is a switching device. The power semiconductor device can be an IGBT, a MOSFET, a HEMT, a diode, or a thyristor. In this case, the electronic device is or includes (for example) a power semiconductor module having one or more power semiconductor devices.

[0036] The power semiconductor module may include a substrate having a top metallization layer and optionally a bottom metallization layer. At least one power semiconductor device may be mounted on the top side of the substrate where the top metallization layer is located, for example, it may be mounted on the top metallization layer. For example, the substrate may be a DBC (direct copper) substrate or a DBA (direct aluminum) substrate or an AMB (active metal support) substrate with an isolation ceramic layer or an IMS (isolated metal substrate) with an isolation resin layer. In addition, the power semiconductor module may include terminals (main terminals and optional auxiliary terminals) for external electrical connection. The terminals may be implemented by a terminal structure, for example, the terminal structure is sheet-shaped and / or made of metal and / or formed in one piece. Terminals of other shapes, such as threaded hollow cylinders (such as nuts), are also possible. The terminal area of ​​the terminal structure is exposed to enable external electrical contact. The terminal structure may be bonded to the top metallization layer, or may be implemented by the top metallization layer. The terminals may not only directly connect the chip, but also control the electronic device.

[0037] The power semiconductor module may further include a housing. The housing may be formed of an electrically isolating material such as a resin and / or a gel. The (one or more) power semiconductor devices may be embedded in the housing. The terminal structure may be at least partially embedded in the housing. The terminal region of the terminal structure may extend from the housing, for example at a side thereof. The housing may include a housing frame surrounding the cavity. The cavity may be filled with a gel.

[0038] Furthermore, the power semiconductor module may include a base plate. For example, the base plate is used for cooling. The substrate may be mounted on the base plate, for example, with the bottom metallization layer facing the base plate. The base plate may be made of a metal, such as Cu or Al or an alloy thereof, or of a composite material, such as aluminum silicon carbide or magnesium silicon carbide. The base plate may include cooling structures, such as pin fins or ribs, on the side facing away from the substrate.

[0039] Here, the lateral direction is a direction parallel to the main extension plane of the substrate. The vertical direction is a direction perpendicular to the main extension plane of the substrate.

[0040] According to another embodiment, the sensor element is placed on the power semiconductor device.

[0041] According to another embodiment, the sensor element is placed in an area next to the power semiconductor device. For example, the sensor element is placed on a top metallization layer of the substrate next to the power semiconductor device and / or between two adjacent power semiconductor devices. The top metallization layer can then form the measurement surface.

[0042] Placing the sensor element on the power semiconductor device has some advantages compared to placing the sensor element on a substrate next to the power semiconductor device, or even on a separate substrate next to the substrate of the electronic device on which the power semiconductor device is mounted. For example, the quality of the determination of the chip temperature improves as the distance between the chip and the temperature sensor decreases. In fact, in this case, the real temperature of the chip can be derived more accurately from the sensor readings by using a thermal model. In addition, in the case of the sensor element being placed directly on the chip, temperature changes caused by large distances and the time delay of the corresponding measurement can be significantly reduced.

[0043] Another advantage of placing the sensor element on the power semiconductor device is that if more than one heat-generating chip is mounted on the substrate, the sensor reading is primarily directed to one chip, rather than an average of the chips. In the case where the sensor element is placed between the chips on the substrate, the measured temperature may not be directed to the temperature of the thermally most adverse or most degraded chip. In the worst case, a severe degradation of the bond connection under one chip will not be detected.

[0044] Furthermore, in case the sensor element is placed on the chip, it can be avoided that excessively high temperatures of the chip cannot be detected due to thermally non-conductive deteriorated die bonds.

[0045] Additionally, placing the sensor element on the top metallization layer next to the power semiconductor device consumes space on the substrate surface, reducing the available space for the chip. This can also have a negative impact on the thermal resistance and thus the rated cost per ampere.

[0046] Furthermore, many products are initially developed without integrated sensor elements. As a result, there may be no area on the substrate available for placement of sensor elements. However, at the same time, there is a strong trend among customers to request the implementation of thermal sensors.

[0047] The electronic device may include more than one designated sensor unit. For example, several power semiconductor devices are respectively assigned such sensor units, whose sensor elements are mounted on the corresponding power semiconductor devices. One or more sensor elements of one or more sensor units may also be mounted on the top metallization layer of one or more substrates next to or between (one or more) power semiconductor devices, and one or more sensor elements of one or more sensor units are mounted on one or more power semiconductor devices. For example, there may be one such sensor unit per substrate.

[0048] According to another embodiment, the measurement surface is formed by a top electrode of the power semiconductor device. The top electrode of the power semiconductor device may be, for example, a source / emitter electrode or a drain / collector electrode. The top electrode may be made of a metal such as Cu or Al or a corresponding alloy.

[0049] According to another embodiment, the bottom electrode of the sensor element is in dry electrical contact with the top electrode of the power semiconductor device.The contact between the bottom electrode of the sensor element and the top electrode of the power semiconductor device may also be a thermal contact.

[0050] Furthermore, in case the sensor element is mounted on the top metallization layer of the substrate, there may be dry electrical contact between the bottom electrode of the sensor element and the measuring surface (top metallization layer).

[0051] The sensor reading of the sensor element is for example between the contact element and an output terminal of the electronic device (for example, an AC terminal). Alternatively, the sensor reading may be between the contact element and an input terminal of the electronic device (for example, a DC+ or DC- terminal).

[0052] According to another embodiment, the contact element is electrically and mechanically connected (particularly fixed) to an auxiliary terminal of the electronic device. The auxiliary terminal is (for example) formed by an auxiliary terminal structure of the electronic device. The auxiliary terminal structure is (for example) a sheet metal element or a nut or a hollow (metal) cylinder. (One or more) auxiliary terminals are different from the main terminals or power terminals of the electronic device. The main terminals can be AC, DC-, and DC+ terminals. In particular, the auxiliary terminals are configured to carry less current than the main terminals. The auxiliary terminals can be partially embedded in the housing of the electronic device. The auxiliary terminals can be terminals for controlling power semiconductor devices, such as terminals for measurement / detection. They can be auxiliary emitter or auxiliary collector terminals or gate terminals or terminals for connecting sensors.

[0053] According to another embodiment, the contact element is electrically and mechanically connected to the auxiliary terminal by a screw connection. Alternatively, other connection methods, such as welding, soldering, crimping, or gluing are also possible.

[0054] The auxiliary terminal (for example) is an externally electrically connectable terminal of an electronic device. That is, the terminal area of ​​the auxiliary terminal is exposed and is freely accessible. For example, the terminal area of ​​the auxiliary terminal is exposed and / or extends out of the housing on the side of the housing. Alternatively, the auxiliary terminal can be exposed and / or extend out of the housing on its top side, for example, when the auxiliary terminal is a nut, a vertical pin, or a hollow sleeve.

[0055] Besides connecting the contact element to the auxiliary terminal, other ways of fixing the contact element in the electronic device are also conceivable.

[0056] According to another embodiment, the contact element is fixed to an electrically insulating element (such as a housing and / or a resin body) of the electronic device. This means in particular that there is a direct connection between the contact element and the electrically insulating element. The fixing to the electrically insulating element can keep the contact element in a mechanically biased state. For example, the contact element can be assembled into the housing and surrounded by a form-fitting shape. Alternatively, a nut (e.g., a metal nut) can be embedded in the housing and the contact element can be screwed into the nut.

[0057] According to another embodiment, a portion of the contact element is exposed, for example, at the top side of the electronic device. The exposed portion can constitute a terminal area of ​​the contact element for external electrical connection of the contact element. The sensor element can be powered and / or read out via the exposed portion.

[0058] According to another embodiment, the thermally conductive material is arranged between the measuring surface and the sensor element. The thermally conductive material can be a slurry filled with particles (e.g., conductive particles). The thermally conductive material can be conductive or electrically insulating. The slurry is liquid and / or viscous. Alternatively, the thermally conductive material can be a thermally conductive sheet (e.g., an elastic sheet).

[0059] According to another embodiment, the electronic device includes at least one (i.e., one or more) power semiconductor modules and a cooler for the power semiconductor modules. The cooler may be a carrier of the power semiconductor module. For example, the cooler is configured to guide a cooling liquid through. The cooler may include a cooling channel for cooling the liquid. The cooler may be made of a metal (e.g., copper or aluminum). The power semiconductor module may be mounted on the cooler, with the bottom metallization layer and / or the base plate facing the cooler.

[0060] According to another embodiment, the measuring surface is formed by the cooler, for example by its top surface. The sensor element can then be used to measure the temperature of the cooler. A dry electrical contact can be formed between the cooler and the sensor element.

[0061] According to another embodiment, the measuring surface is formed by the surface of the base plate.The sensor element can then be placed next to the substrate or between two adjacent substrates mounted on the base plate.

[0062] According to another embodiment, at least one of the measuring surface and the surface of the sensor element facing the measuring surface is roughened, in particular to increase the contact surface. The rough surface may be impressed into the adjoining surface, thus increasing the contact surface. In addition, in this way, a form-fitting connection can be established. In addition, undesirable oxide layers may be destroyed in this way, or impurities / contaminants on the adjoining surface may be penetrated.

[0063] According to another embodiment, the rough surface has an average roughness of at least 1 μm or at least 1.6 μm or at least 2 μm.

[0064] Next, a method for mounting the sensor element is specified. An electronic device according to any embodiment described herein can be produced by means of this method. Therefore, all features disclosed for the electronic device are also disclosed for the method, and vice versa.

[0065] According to one embodiment, a method for mounting a sensor element comprises the step of providing a sensor unit according to any of the embodiments described herein. In a further step, a component for an electronic device is provided. The component has a measuring surface, and a physical quantity at the measuring surface is to be measured by means of the sensor element. In a further step, the sensor unit is mounted on the component. The mounting of the sensor unit comprises the step of placing the sensor element on the measuring surface. The mounting also comprises the step of mechanically biasing the contact element so that it exerts a force on the sensor element that acts in a direction toward the measuring surface. Furthermore, the mounting comprises the step of fixing at least a portion of the mechanically biased contact element relative to the component so that the contact element remains in a mechanically biased state.

[0066] The component may be, for example, a power semiconductor device, a substrate or a top metallization layer of a substrate, a bottom plate or a cooler. Thus, the measurement surface may be a top electrode of a power semiconductor device or a top metallization layer of a substrate or a surface of a bottom plate or a surface of a cooler.

[0067] The step of placing the sensor element can be performed before or after the biasing contact element. The sensor element can be placed directly on the measuring surface so that it is adjacent to the measuring surface. For example, the sensor element is fixed or connected to the measuring surface only by a form-fitting and / or force-fitting connection, that is, no material-locked connection is formed between them (i.e., a dry connection is formed). Therefore, the sensor element is neither glued nor welded, neither sintered nor welded to the measuring surface, for example. In the case where the sensor element is placed on the measuring surface, a dry electrical contact can be established between the sensor element and the measuring surface. The biased sensor element can press the sensor element against the measuring surface.

[0068] For example, the contact element is fixed relative to the component such that the fixed and biased contact element continues to exert a force on the sensor element in a direction towards the measurement surface. For example, at least a portion of the contact element remote from the sensor element is fixed relative to the component.

[0069] According to another embodiment, fixing at least a portion of the mechanically biased contact element relative to the component includes screwing the contact element into a thread of the electronic device. Additionally or alternatively, fixing can include welding, sintering, soldering, gluing, or crimping the contact element to the component of the electronic device.

[0070] After placing the sensor element on the measuring surface, a casting process can be performed, in which, for example, different components of the electronic device, such as power semiconductor devices, are cast into a casting material, which can be a gel. The contact element can be fixed relative to the component with the measuring surface with the help of the casting process.

[0071] Hereinafter, a sensor unit for an electronic device, an electronic device, and a method for installing a sensor element will be explained in more detail with reference to the accompanying drawings based on exemplary embodiments. The accompanying drawings are included to provide further understanding. In the accompanying drawings, elements of the same structure and / or function may be represented by the same reference numerals. It should be understood that the embodiments shown in the accompanying drawings are illustrative representations and are not necessarily drawn to scale. As long as the functions of elements or components in different drawings correspond to each other, their descriptions are not repeated for each of the following figures. For clarity, elements may not appear with corresponding reference numerals in all drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figures 1 to 4 An exemplary embodiment of a method for mounting a sensor element and different positions in an exemplary embodiment of a sensor unit and an electronic device are shown,

[0073] Figures 5 to 7 shows different positions in further exemplary embodiments of the method and further exemplary embodiments of the sensor unit and the electronic device,

[0074] Figures 8 to 10 shows different positions in further exemplary embodiments of the method and further exemplary embodiments of the sensor unit and the electronic device,

[0075] Fig.11 and Fig.12 shows different locations in a further exemplary embodiment of the method and in a further exemplary embodiment of the electronic device,

[0076] Fig.13 and 14 shows further exemplary embodiments of electronic devices and sensor units,

[0077] Figures 15 to 17 shows different positions in further exemplary embodiments of the method and further exemplary embodiments of the sensor unit and the electronic device,

[0078] Fig.18 and Fig.19 A further exemplary embodiment of an electronic device is shown. DETAILED DESCRIPTION

[0079] Figure 1The position of an exemplary embodiment of a sensor unit 10 for an electronic device 100 is shown. The sensor unit 10 comprises a contact element 2 and a sensor element 1. The contact element 2 is a spring contact element that can be mechanically biased by compression. The contact element 2 is formed of a metal such as Cu, Al, or steel, for example.

[0080] The sensor element 1 is, for example, a temperature sensor (such as a thermistor). It can be an NTC, a PTC or a platinum resistor (for example, PT100 or PT1000), or a thermocouple. The sensor element 1 comprises a top electrode 1a and a bottom electrode 1b. Both electrodes 1a, 1b can be conductive, in particular metallic. The electrodes 1a, 1b are arranged for reading out the sensor element 1, but can also be used for supplying a current and / or a voltage to the sensor element 1.

[0081] The contact element 2 is fixed and electrically connected to the sensor element 1 (i.e., its top electrode 1a). The mechanical and electrical connection between the contact element 2 and the sensor element 1 is achieved, for example, by a material-locked connection (e.g., welding, sintering, soldering, or gluing connection). Since the contact element 2 is electrically conductive, the sensor element 1 can be read out with the help of the contact element 2.

[0082] Figure 2 The further position of the assembly of different components 3, 6 for the electronic device is shown. One component is a substrate 6 with a top metallization layer 6a. The substrate 6 is, for example, a DBC substrate. The other component is a power semiconductor device 3 mounted on the top side of the substrate 6 and electrically connected to it by wire bonding. The power semiconductor device 3 comprises a top electrode 3a, which constitutes a measurement surface 30, which can be measured by means of Figure 1 The sensor element 1 measures a physical quantity at a measurement surface 30. For example, the power semiconductor device 3 is an IGBT or a power MOSFET, and its top electrode 3a is a source electrode or an emitter electrode, respectively.

[0083] Figure 3 Shows Figure 1 The sensor unit 10 with the composite of the sensor element 1 and the contact element 2 is placed on the power semiconductor device 3 in such a position that the sensor element 1 abuts the measuring surface 30. No additional connecting material is used for forming a material-locked connection between the sensor element 1 and the measuring surface 30. Therefore, there is a dry connection between the sensor element 1 and the measuring surface 30.

[0084] exist Figure 4 , an exemplary embodiment of the electronic device 100 is shown. The electronic device 100 is a power semiconductor module 100. Figure 3The power semiconductor module 100 is obtained in the arrangement of the contact element 2, which has been compressed or bent, thereby entering its biased state. In this biased state, the contact element 2 applies a force to the sensor element 1 in the direction toward the measuring surface 30, thereby pressing the sensor element 1 against the measuring surface 30. In this way, due to the increase in friction (dry connection), the sensor element 1 is firmly held on the measuring surface 30 and connected to the measuring surface 30, and a firm and reliable electrical connection (dry electrical contact) is established between the measuring surface 30 and the sensor element 1.

[0085] Figure 4 The device can be produced as follows: In the biased state of the contact element 2, the resin 61 has been applied to the substrate 6 and encapsulates a part of the contact element 2. After drying the resin 61, the contact element 2 is fixed in its biased state. The resin body 61 thus obtained forms the housing frame 61 of the power semiconductor module 100. For example, the cavity surrounded by the housing frame can be filled with gel.

[0086] Alternatively, Figure 4 The device can be produced as follows: a prefabricated housing frame 61 can be mounted on the substrate 6, and then the contact element 2 can be clamped in the housing frame 61 to keep it in a biased state. Alternatively, the contact element 2 can be at least partially embedded in the housing frame 61 as an integral part.

[0087] A portion of the contact element 2 on the top side of the power semiconductor module 100 is not covered by the resin body 61 but is exposed. This portion constitutes a terminal region of the contact element 2 for external electrical connection of the contact element 2. Thus, for example, the sensor element 1 can be read out via the contact element 2 and the DC- or AC-terminals of the power semiconductor module 100.

[0088] Figure 5 The position of a further exemplary embodiment of a sensor unit 10 is shown. In this case, the contact element 2 is formed by a press stylus. The press stylus comprises a spring 22 for pressing a tip element or a plunger of the press stylus towards the measuring surface and for pressing a hollow sleeve of the press stylus away from the cylinder, respectively. The tip element of the press stylus is mechanically fixed and electrically connected to a sensor element 1 (the sensor element 1 is, for example, the same as the sensor element described previously). The mechanical and electrical connection between the tip element and the sensor element 1 can be established in the same way as described previously.

[0089] The contact element 2 further comprises means 21 for a screw connection, namely an external thread 21 .

[0090] Figure 6The position of the assembly providing different components for the electronic device is shown. The assembly also includes a substrate 6 and a power semiconductor device 3 mounted thereon. In addition, the assembly includes a resin body 61, in which an auxiliary terminal (structure) 4 is partially embedded. The auxiliary terminal structure 4 protrudes from the right side of the resin body 61, wherein the protruding portion constitutes a terminal area for external electrical connection of the auxiliary terminal 4.

[0091] Another exposed portion of the auxiliary terminal structure 4 comprises a through hole having means 41 for screw connection, ie an internal thread. The through hole is located vertically above the measuring surface 30 of the power semiconductor device 3 .

[0092] exist Figure 7 , another exemplary embodiment of the electronic device 100 is shown. Again, the electronic device 100 is a power semiconductor module 100. The power semiconductor module 100 is Figure 5 The sensor unit 10 is screwed into Figure 6 The sensor element 1 is thus placed on the measuring surface 30 by tightening the spring 22 of the contact element 2, so that the contact element 2 is biased. Therefore, the sensor element 1 is pressed against the measuring surface 30 by the biased contact element 2, thereby forming a reliable dry connection and a dry electrical contact between the measuring surface 30 and the sensor element 1. Due to the threaded connection between the auxiliary terminal structure 4 and the contact element 2, the contact element 2 is fixed in place and in its biased state. Then, a casting material 7, for example in the form of a gel, is applied. The casting material 7 and the resin body 61 together form the housing of the power semiconductor module 100. For example, the sensor element 1 can be read out through the contact element 2 and the auxiliary terminal 4 and through another terminal (for example, a main terminal electrically connected to the measuring surface of the chip).

[0093] exist Figure 8 Another exemplary embodiment of the sensor unit 10 is provided. In this case, the sensor unit 10 includes two contact elements 2, each of which is implemented as a press stylus. One contact element 2 is fixed and electrically connected to the top electrode 1a of the sensor element 1, and the other contact element 2 is fixed and electrically connected to the bottom electrode 1b. Therefore, the sensor element 1 can be read out via the two contact elements 2. Figure 8 As shown, in order for both the top electrode 1 a and the bottom electrode 1 b to be able to contact the contact element 2 from the top side, the bottom electrode 1 b protrudes beyond the top electrode 1 a in the lateral direction.

[0094] Alternatively, the sensor element 1 can comprise the two electrodes 1 a and 1 b on its top side, so that in this case, the sensor element 1 can also be contacted with the two contact elements 2 from the top side.

[0095] Fig. 9 Shows the positions of components that provide several components 3, 6, 61, 62 again. Here, one component 62 is a circuit board (e.g., PCB) that is mounted on the resin body 61 and laterally overlaps the power semiconductor device 3. The component 62 can be a control board and can include control devices.

[0096] In Fig.10 again mounts Figure 8 the sensor unit 10, where the sensor element 1 is placed on the measurement surface 30 of the power semiconductor device 3. The contact element 2 of the sensor unit 10 is screwed into the threaded hole of the circuit board 62, so as to be mechanically fixed to the circuit board 62 and at the same time be mechanically biased, such that the sensor element 1 is pressed against the measurement surface 30.

[0097] Fig.10 Shows another exemplary embodiment of the electronic device 100 in the form of a power semiconductor module 100. In this case, the two contact elements 2 of the sensor unit 10 project out of the circuit board in the vertical direction, such that the terminal regions of the two contact elements 2 are exposed on the top side of the power semiconductor module 100. These terminal regions of the two contact elements 2 can be electrically connected for reading out the sensor element 1.

[0098] Fig.11 Shows the positions of components that provide the substrate 6, the power semiconductor device 3, and the resin body 61. A hole is formed in the resin body 61 above the top metallization layer 6a. In this case, the top metallization layer 6a forms a measurement surface 60, and the physical quantity (e.g., temperature) can be measured at this measurement surface 60.

[0099] In Fig.12 the position of, the sensor unit 10 is mounted by screwing Figure 5 the sensor unit 10 into the hole in the resin body 61, such that the sensor element 1 is again placed on the measurement surface 60. In order to enable a threaded connection, the hole in the resin body 61 can include an internal thread. Alternatively, a nut with an internal thread can be embedded in the resin body (not shown).

[0100] Fig.13 Shows an exemplary embodiment of the electronic device 100 as a power semiconductor module 100. In this case, the thermal conductive material 5 (e.g., in the form of a paste or a flexible material sheet filled with conductive and / or thermal conductive particles such as metal particles) is arranged between the sensor element 1 and the top electrode 3a. A dry electrical contact can be formed between the material 5 and the sensor element 1 and / or between the material 5 and the top electrode 3a.

[0101] In Fig.13In the case of , the thermally conductive material 5 is also electrically conductive so as to establish an electrical contact between the top electrode 3a and the sensor element 1. Fig.10 If such a thermally conductive material 5 is used in the exemplary embodiment of FIG. 5 , the material 5 may be electrically isolating.

[0102] exist Fig.14 In an exemplary embodiment of the electronic device 100, the bottom side of the sensor element 1, i.e. the bottom electrode 1a, comprises a roughening with a plurality of protrusions and a plurality of depressions. For example, the average roughness of such a roughening is at least 1.6 μm. In the case where the sensor element 1 is pressed against the measuring surface 30 by the biased contact element 2, the protrusions can be impressed into the measuring surface 30 and thus improve the dry electrical contact, for example by penetrating and / or locally destroying the oxide layer that is present. For this purpose, the measuring surface 60 can be relatively soft compared to the material of the rough surface.

[0103] Fig.15 The position of another exemplary embodiment of a sensor unit 10 for an electronic device is shown. In this case, the contact element 2 comprises a press-on contact pin as described above and further comprises a terminal structure 24 which is mechanically and electrically connected to the press-on contact pin. This connection can be established in different ways, for example, by screws, welding, gluing, sintering, welding, etc. The terminal structure 24 is a sheet-like element and can be formed of a metal (for example, Cu or a Cu alloy).

[0104] exist Fig.16 , again providing an assembly for the different components of the electronic device 100 , including the substrate 6 , the power semiconductor device 3 , and the resin body 61 .

[0105] Fig.17 An exemplary embodiment of an electronic device 100 in the form of a power semiconductor module 100 is shown. Fig.15 The sensor unit 10 is mounted to Fig.16 The auxiliary terminal structure 24 is, for example, bonded to the resin body 61 so that the pressing contact pins are held in their biased state. Fig.17 In the embodiment of the present invention, a part of the sensor unit 10 and the power semiconductor device 3 are embedded in the casting 7 , for example in the form of gel. The terminal structure 24 forms an auxiliary terminal of the power semiconductor module 100 .

[0106] Fig.18 An exemplary embodiment of an electronic device 100 is shown in a top view on a measurement surface 30. As can be seen here, the sensor element 1 is laterally placed on the measurement surface 30 between two adjacent bond wires, wherein both adjacent bond wires are electrically and mechanically connected to the top electrode 3a of the power semiconductor device 3.

[0107] Fig.19 An exemplary embodiment of an electronic device 100 in the form of an assembly of two power semiconductor modules 8 mounted on a cooler 9 is shown. The cooler 9 is configured to cool the power semiconductor module 8. For example, the cooler 9 includes a channel for guiding a cooling liquid through the cooler 9. The cooler 9 is formed of a metal such as Cu or Al, for example. An exposed surface of the cooler 9 is used as a measuring surface 90. A nut 91 having an internal thread is mounted on the measuring surface 90. Figure 5 The sensor unit 10 is screwed into the nut 91 , so that the sensor element 1 is placed on the measuring surface 90 and the contact element 2 is fixed to the nut 91 in its biased state.

[0108] Instead of the cooler 9 forming the measuring surface, the base plate of the power semiconductor module can also form the measuring surface.

[0109] like Figures 1 to 19 The embodiments shown represent exemplary embodiments; therefore, they do not constitute a complete list of all embodiments according to the improved sensor unit, improved electronic device, and improved method. For example, the actual sensor unit, electronic device, and method may differ from the embodiments shown in terms of arrangement, equipment, and elements.

[0110] Reference Mark

[0111] 1Sensor element

[0112] 1a Top electrode

[0113] 1b Bottom electrode

[0114] 2Contact elements

[0115] 3 Power semiconductor devices 3a Top electrode 4 auxiliary terminals (structure)

[0116] 5. Thermally conductive materials

[0117] 6 substrates

[0118] 6a Top metallization layer

[0119] 7 Casting / Gel

[0120] 8Power semiconductor modules

[0121] 9 Cooler 10Sensor unit for electronic equipment 21 Device for threaded connection

[0122] 22 Spring

[0123] 24 auxiliary terminal structure

[0124] 30 Measurement surfaces

[0125] 41 Device for threaded connection

[0126] 60 measuring surfaces 61 resin / resin body / shell frame

[0127] 62 Circuit Board

[0128] 90 measuring surface

[0129] 91 Nut 100 electronic devices

Claims

1. A sensor unit (10) for an electronic device (100), include: - a sensor element (1) for measuring a physical quantity in the electronic device (100); - a contact element (2) configured to be mechanically biased, wherein - the contact element (2) comprises a pressing contact pin, - the contact element (2) is fixed to the sensor element (1) and is electrically connected thereto, - The sensor unit (10) is configured to be mounted on the component (3, 6, 9) of the electronic device by placing the sensor element (1) on a measuring surface (30, 60, 90) of the component (3, 6, 9) and mechanically biasing the contact element (2) so that the mechanically biased contact element (2) exerts a force on the sensor element (1) that acts in the direction of the measuring surface (30, 60, 90).

2. The sensor unit (10) according to claim 1, in, - The sensor element (1) is a temperature sensor.

3. The sensor unit (10) according to claim 1 or 2, in, - The contact element (2) comprises a spring contact.

4. The sensor unit (10) according to any one of the preceding claims, in, The contact element (2) is fixed to the sensor element (1) by a material-locked connection.

5. The sensor unit (10) according to any one of the preceding claims, in, The contact element (2) comprises means (21) for screwing the contact element (2) into a thread of the electronic device (100).

6. The sensor unit (10) according to any one of the preceding claims, in, the sensor element (1) comprises a top electrode (1a) located on a top side of the sensor element (1) and a bottom electrode (1b) located on a bottom side of the sensor element (1) opposite to the top side, - the contact element (2) is electrically connected and fixed to the top electrode (1a) of the sensor element (1), - The bottom electrode (1 b) of the sensor element (1) is exposed in an unmounted configuration of the sensor unit (10).

7. An electronic device (100), include: - A sensor unit (10) according to any one of the preceding claims; A component (3, 6, 9) having a measuring surface (30, 60, 90) at which a physical variable is measured by means of the sensor element (1), wherein - the sensor element (1) is placed on the measuring surface (30, 60, 90), The contact element (2) is mechanically biased so as to exert a force on the sensor element (1) which acts in the direction of the measuring surface (30, 60, 90).

8. The electronic device (100) according to claim 7, include: - a power semiconductor device (3), wherein - The sensor element (1) is placed on the power semiconductor device (3).

9. The electronic device (100) according to claim 8, in, - the measurement surface (30) is formed by the top electrode (3a) of the power semiconductor device (3), - the sensor unit (10) is a sensor unit (10) according to claim 6, The bottom electrode (1b) of the sensor element (1) is in dry electrical contact with the top electrode (3a) of the power semiconductor device (3).

10. The electronic device (100) according to any one of claims 7 to 9, in, The contact element (2) is electrically and mechanically connected to an auxiliary terminal (4) of the electronic device (100).

11. The electronic device (100) according to any one of claims 7 to 9, in, - The contact element (2) is fixed to an electrically insulating element of the electronic device (100).

12. The electronic device (100) according to any one of claims 7 to 11, in, A portion of the contact element (2) is exposed and constitutes a terminal region of the contact element (1) for external electrical connection of the contact element (2).

13. The electronic device (100) according to any one of claims 7 to 12, in, - a heat-conducting material (5) is arranged between the measuring surface (30, 60, 90) and the sensor element (1), - The thermally conductive material (5) comprises a paste filled with conductive particles.

14. The electronic device (100) according to any one of claims 7 to 13, include: - at least one power semiconductor module (8) and a cooler (9) for the at least one power semiconductor module (8), - The measuring surface (90) is formed by the cooler (9).

15. The electronic device (100) according to any one of claims 7 to 14, in, at least one of the measuring surface (30, 60, 90) and the surface of the sensor element (1) facing the measuring surface (30, 60, 90) is roughened to increase the contact surface, - the rough surface has an average roughness of at least 1.6 μm.

16. A method for mounting a sensor element, include: - providing a sensor unit (10) according to any one of claims 1 to 6, - providing a component (3, 6, 9) for an electronic device (100), the component having a measuring surface (30, 60, 90), a physical quantity at the measuring surface being measured by means of the sensor element (1); - mounting the sensor unit (10) on the component (3, 6, 9), The installation includes: - placing the sensor element (1) on the measuring surface (30, 60, 90), - mechanically biasing the contact element (2) so that it exerts a force on the sensor element (1) that acts in the direction of the measuring surface (30, 60, 90), and - fixing at least a portion of the mechanically biased contact element (2) relative to the member (3, 6, 9) so that the contact element (2) remains in a mechanically biased state.

17. The method according to claim 16, in, - fixing at least a portion of the mechanically biased contact element (2) relative to the member (3, 6, 9) comprises screwing the contact element (1) into a thread of the electronic device (100).

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