Current sensor package with continuous insulation

Abstract

A current sensor package (100) includes a current path (102) and a sensing device (104). The sensing device is spaced apart from the current path (102) and is configured to sense a magnetic field generated by a current flowing through the current path (102). The sensing device (104) further includes a sensor element (106). The sensing device (104) is electrically connected to a conductive trace (112). A seal (116) extends continuously between the current path (102) and the sensing device (104).

Description

Technical Field

[0001] The present invention relates to a current sensor package and a method of manufacturing a current sensor package. Background Art

[0002] A package may be referred to as an encapsulated electronic chip with electrical connections extending from the encapsulation and mounted to an electronic peripheral device, such as a printed circuit board.

[0003] Magnetic current sensors, ie, current sensors that sense the magnetic field generated by the current to be measured, provide contactless measurement of the current and allow electrical separation of the current to be measured and the sensor.

[0004] Packaging cost is a key driver in the industry. Related to this are performance, size, and reliability. Different packaging solutions are diverse and must address specific application requirements.

[0005] DE 112012003079T5 discloses a current sensor encapsulated in an integrated circuit package, comprising a magnetic field sensing circuit, a current conductor, and an insulator that meets the safety isolation requirements for reinforced insulation under UL 60950-1. The insulator is configured as an insulating structure comprising at least two layers of sheet-like material. The insulating structure is dimensioned so that the plastic material forming the molded plastic body of the package provides reinforced insulation. According to one embodiment, the insulating structure comprises two layers of insulating tape. Each insulating tape layer comprises a polyimide film and an adhesive. The insulating structure and the molded plastic body can be configured to achieve a rated working voltage of at least 500 VRMS. Summary of the Invention

[0006] It may be desirable to manufacture a current sensor package with a high level of reliability.

[0007] According to a first aspect of the herein disclosed subject matter, a current sensor package is provided.

[0008] According to an embodiment, the current sensor package includes a current path; a sensing device (e.g., a sensor chip) that is spaced apart from the current path and is configured to sense a magnetic field generated by a current flowing through the current path; the sensing device includes a sensor element that is electrically connected to a conductive trace; the current sensor package also includes a seal that extends continuously between the current path and the sensing device.

[0009] According to a second aspect of the herein disclosed subject matter, a method of manufacturing a current sensor package is provided.

[0010] According to an embodiment, the method includes: providing a current path; providing a sensing device (e.g., a sensor chip) configured to sense a magnetic field generated by a current flowing through the current path; the sensing device includes a sensor element; the sensing device is arranged to be spaced apart from the current path; electrically connecting the sensing device to a conductive trace; and providing a seal extending continuously between the current path and the sensing device.

[0011] According to other embodiments of the first aspect, the current sensor package is suitable for providing one or more functions of the embodiments disclosed herein and / or providing one or more required functions of the embodiments disclosed herein, in particular the functions required by the embodiments of the first and second aspects disclosed herein.

[0012] According to further embodiments of the second aspect, the method is suitable for providing one or more functionalities of the embodiments disclosed herein and / or providing one or more required functionalities of the embodiments disclosed herein, in particular embodiments of the first and second aspects disclosed herein.

[0013] Description of Other Exemplary Embodiments

[0014] In the following, further exemplary embodiments of the subject matter disclosed herein are described, any number of which, and any combination thereof, may be realized when practicing aspects of the subject matter disclosed herein.

[0015] In the context of the present application, the term "extending continuously" may particularly denote an extension (eg of the seal) without any internal interface (interface within the seal).

[0016] In the context of the present application, the term “current sensor package” (or simply “package”) may particularly denote at least one at least partially encapsulated sensor chip having at least one external electrical contact.

[0017] The term "sensing device" may particularly denote a discrete sensor element or a sensor chip comprising a sensor element.

[0018] The term "sensor chip" may particularly denote, for example, a chip having at least one integrated sensor element (e.g., a Hall sensor or a magnetoresistive sensor) in a surface portion thereof. According to an embodiment, the at least one integrated sensor element is located on the same main surface as the contact pads of the sensor chip. The sensor chip may be a bare die or may already be packaged or encapsulated.

[0019] In the context of the present application, the term "seal" may particularly denote a substantially electrically insulating and preferably thermally conductive material surrounding (e.g., hermetically surrounding) a current path to provide mechanical protection, electrical insulation, and optionally contribute to heat dissipation during operation. Such a seal may be, for example, a molding compound.

[0020] In the context of this application, the term "carrier" may particularly denote an electrically conductive structure that can serve as a support for (at least one) chip. Furthermore, the carrier may facilitate electrical connections between components and / or facilitate electrical connections to, for example, the periphery of a current sensor package. In other words, the carrier may fulfill a mechanical support function and / or an electrical connection function.

[0021] In the context of the present application, the term "component" may particularly denote any electronic component that can be mounted and electrically connected to a package to provide the package with its functionality. In particular, a component may be a passive component such as an inductor (in particular a coil), a capacitor (for example a ceramic capacitor), an ohmic resistor, an inductor, a diode, a transformer, a sensor, etc. In particular, a component that cannot control the current by another electrical signal may be denoted as a passive component. However, a component may also be an active component, in particular a component that can control the current by another electrical signal. An active component may be an analog electronic filter, an oscillator, a transistor or another integrated circuit element that can amplify a signal or generate power gain.

[0022] Depending on the embodiment, the package may be, for example, a surface mount device (SMD) or a through hole device (THD).

[0023] In an embodiment, the package is configured for an operating voltage in a range between 100 Volts (V) and 1000 V, for example, for an operating voltage of approximately 800 V.

[0024] The term "device" may particularly denote any device adapted to comprise a package. In particular, according to an embodiment, the device is a powertrain of an at least partially electrically driven vehicle, such as an electric vehicle or a hybrid vehicle.

[0025] According to an embodiment, the package provides a high degree of reliability and complies with safety requirements. The higher the requirements for electrical insulation strength and long-term reliability between the current path and the sensor device, the more important the internal interfaces of the electrical insulation are. According to an embodiment, internal interfaces of the electrical insulation are avoided, in particular internal interfaces between the current path and the sensing device and / or the current path and the conductive trace. Avoiding internal interfaces is advantageous because together with delamination paths of internal interfaces, leakage or even clearing paths may be opened, which may lead to greater leakage currents or even breakdown. In breaks or cracks in the electrical insulation, discharges may occur, which may lead to long-term degradation of the insulation material and, in the worst case, to breakdown events.

[0026] Salvage insulation represents the highest level of confidence in isolation reliability and protection against electric shock (e.g., caused by unexpected voltage transients). This quality level is called "Basic" or, for a higher degree of resistance, "Reinforced." Depending on the latter level, for example, the ability to survive transient voltages near the end of a product's life must be ensured, in contrast to lifetime protection.

[0027] On the other hand, achieving high-reliability electrical isolation using inexpensive standard semiconductor packaging technologies can sometimes be difficult, especially in the low- and medium-voltage range. Here, a reliable single-layer insulation can be advantageous. In the best case, this insulation is derived from the packaging concept and materials, significantly reducing costs. Specifically, additional intervening layers can increase packaging costs, as is the case with stacked die approaches, where a separate insulating plate is used for electrical isolation.

[0028] Embodiments of the subject matter disclosed herein utilize a seal that extends continuously between the current path of a current sensor package and the sensing device. The continuously extending seal can achieve delamination-resistant insulation of the current path in the sensing device. This, in turn, enables reliable insulation within the package.

[0029] According to an embodiment, the seal also extends continuously between the current path and the conductive trace (to which the contact path of the sensing device is electrically connected).Thus, in an embodiment, the seal extends continuously between the current path on the one hand and the sensor device and its associated electrical connections on the other hand.

[0030] According to an embodiment, the electrically conductive trace is a carrier, in particular a metal carrier, more particularly a lead frame.

[0031] According to another embodiment, the sensing device is attached to a carrier. For example, in the case where the conductive trace is the carrier, in the method of manufacturing the package, positioning the sensing device may include attaching the sensing device to the conductive trace, and providing the seal may include providing the seal continuously between the current path on the one hand and the sensing device and the conductive trace on the other hand.

[0032] According to another embodiment, the interconnection between the sensing device and the conductive trace is provided by at least one bond wire and / or at least one through silicon via (TSV).

[0033] According to an embodiment, the sensing device has a main surface, a portion of which is attached to the carrier, while the remaining portion of the main surface extends beyond the carrier and over the current path. According to an embodiment, the sensor of the sensing device is located within the sensing device so as to be positioned adjacent to the current path. According to an embodiment, the carrier has an attachment portion to which the portion of the main surface of the sensing device is attached. According to another embodiment, the attachment portion of the carrier is flat.

[0034] According to an embodiment, the sensing device is attached to the seal.For example, the method of manufacturing a package may comprise providing a seal over at least a portion of the current path, wherein positioning the sensing device comprises attaching the sensing device to the seal.

[0035] For example, according to an embodiment, the package includes a pre-molded portion formed by a seal. According to an embodiment, the pre-molded portion extends continuously over at least a portion of the current path and between the current path and the conductive trace. According to an embodiment, the seal extends over at least a portion of the conductive trace. According to an embodiment, a method of manufacturing a current sensor package includes providing a seal around the current path (e.g., around a portion of the current path) and / or around the conductive trace (e.g., around a portion of the conductive trace), thereby providing the pre-molded portion. Thus, in an embodiment, the pre-molded portion includes the seal and at least one of the current path and the conductive trace.

[0036] According to an embodiment, the sensing device is attached to the pre-molded part, for example, in an attachment surface of the pre-molded part. According to an embodiment, the seal has a recess, wherein the attachment surface is provided at the bottom of the recess. In this way, the recess walls surrounding the bottom surface provide mechanical protection for the sensing device. According to another embodiment, the recess is covered with a cover and / or filled with a filling material. The cover / filling material may provide additional protection for the sensing device and / or the bonding wires (if present). According to an embodiment, the filling material comprises silicone, epoxy, etc.

[0037] According to an embodiment, the sensing device is attached to the encapsulation (or in another embodiment, to the carrier) via a die attach layer. According to an embodiment, the die attach layer is applied to the sensing device at wafer level. In other words, according to an embodiment, the die attach layer is applied to the wafer before the wafer is separated into individual dies by, for example, sawing. Typically, for the sawing process, the die attach layer is applied to the wafer in order to attach the wafer to the saw foil. According to an embodiment, the die attach layer is a die attach film (DAF). Since the die attach film usually looks better to the wafer than to the saw foil, removing the individual dies from the saw foil leaves the die attach film on the die. According to an embodiment, the die (sensing device) is attached to the carrier or encapsulation using such a die attach film obtained from the separation process (sawing process). According to another embodiment, the die attach layer comprises a conductive adhesive (e.g., is a layer of conductive adhesive). According to another embodiment, the die attach layer comprises a non-conductive adhesive (e.g., is a layer of non-conductive adhesive). According to another embodiment, the die attach layer may include (or consist of) a solder material, eg a soft solder, a hard solder, a diffusion solder, or the like.

[0038] In another embodiment, the sensing device is mounted (specifically, directly soldered, sintered, or bonded) to the surface of the carrier or the seal. In other words, the solder material, sintering material, and / or glue (particularly conductive glue) may be the only materials between the sensing device on the one hand and the carrier on the other hand.

[0039] According to an embodiment, the current path is formed by a lead frame.

[0040] According to an embodiment, the current path and the conductive trace are initially provided (i.e., in an early manufacturing stage) by a single lead frame element, which includes the current path, the conductive trace, and a connecting portion connecting the current path and the conductive trace. After providing a seal over at least a portion of the current path and the conductive trace, the connecting portion can be removed, thereby obtaining independent, electrically isolated current paths and conductive traces. In other embodiments, any other single carrier (instead of a lead frame) can be used initially to provide the current path and the conductive trace via a single carrier.

[0041] In an embodiment, the carrier is a metal carrier, specifically a lead frame. In the context of the present application, the term "lead frame" can particularly refer to a preferred example of a carrier configured as a sheet metal structure, which can be stamped or patterned to form lead frame segments for mounting the chip, and connecting leads as die segments for electrically connecting the package to the electronic environment when the chip is mounted on the lead frame. In an embodiment, the lead frame can be a metal plate (especially made of copper), for example, which can be patterned by stamping or etching. Forming the carrier as a lead frame is a cost-effective and highly mechanically and electrically advantageous configuration, wherein the low-ohmic connection of the chip (and optionally other components) can be combined with the robust support capability of the lead frame. In addition, the lead frame can contribute to the heat conduction of the package and can eliminate the heat generated by the high thermal conductivity of the metal (especially copper) material of the lead frame during the operation of the chip (and components if present). Due to its simplicity, a lead frame or any other metal carrier can be preferred.

[0042] In an embodiment, at least one sensor chip includes at least one group consisting of a controller circuit, a driver circuit, and a sensor element. All of these circuits can be integrated into a single semiconductor chip or independently integrated into different chips. For example, a corresponding current sensor application can be implemented on the chip, where the integrated circuit components of such a sensor chip can include at least one sensor element and a semiconductor element, such as a transistor (especially a MOSFET, a metal oxide semiconductor field effect transistor), at least one diode, etc.

[0043] In an embodiment, at least one sensing device is at least partially embedded in a separate seal (i.e., another seal that may be physically distinct from the seal that extends continuously between the current path and the sensing device). In other words, two separate seals may be provided in the package, and two separate encapsulation processes may be performed. For example, the sensing device may be encapsulated with a portion of the carrier by a first seal (e.g., a first molding compound). Furthermore, a portion of the sensing device may be encapsulated with the separate seal after the sensing device is attached to the carrier or the first seal.

[0044] In an embodiment, the package comprises a common or overall seal at least partially enclosing the carrier, the sensing device, the (first) seal and the at least one component. Thus, the assembled subassembly consisting of the carrier, the chip and the seal on the one hand, and the further seal and the component on the other hand, can be encapsulated by a further seal as a robust sheet (in particular by a further molding process, in particular an overmolding process) for mechanically protecting all the components of the package.

[0045] In an embodiment, any seal of the (first) seal and / or the independent seal and / or the overall seal comprises a molding compound. Thus, the corresponding seal may comprise a molding, in particular a plastic molding. For example, the corresponding encapsulated components (in particular one or more of the sensing device, the current path and the conductive trace) may be provided by placing the component (or more generally, at least one component) between an upper molding tool and a lower molding tool and injecting a liquid molding material therebetween. After the molding material solidifies, the formation of the seal (here the molded body) is completed. If desired, the molding material can be filled with particles that improve its properties.

[0046] According to one embodiment, a support element for the conductive trace is provided before providing (e.g., injecting) the seal. According to another embodiment, a support element for the current path is provided before providing (e.g., injecting) the seal. The support element can prevent or at least reduce deformation of the corresponding supported element (i.e., the conductive trace or the current path) due to providing (e.g., injecting) the seal.

[0047] According to another embodiment, after providing a seal over at least a portion of the support element and the corresponding supported element (i.e., the conductive trace or current path), the support element is removed. Specifically, according to an embodiment, the support element is removed after the seal (e.g., the molding material) has cured. Removing the support element creates a hole in the seal. According to an embodiment, the hole in the seal is filled with an electrically insulating filler material.

[0048] According to an embodiment, the seal comprises a hole, in particular a hole exposing the conductive trace. According to another embodiment, the seal comprises a hole exposing the current path. According to another embodiment, the hole (ie at least one hole) is filled with an electrically insulating filling material.

[0049] According to an embodiment, the package further comprises a mounting side configured to be mounted to a support (e.g., a printed circuit board (PCB) or direct copper bonding (DCB)). According to another embodiment, the sensor element faces away from the mounting side and / or away from the current path. According to another embodiment, positioning the sensing device comprises positioning the sensor element away from the mounting side and / or away from the current path.

[0050] According to another embodiment, the support is a printed circuit board (PCB). The support can be made in particular from a resin, in particular an epoxy resin, mixed with particles (e.g., fibers, such as glass fibers) if desired. Suitable dielectric materials for the PCB are, for example, prepreg or FR4. A suitable conductive material for the PCB is copper.

[0051] According to an embodiment, the support member is a layered structure comprising a ceramic portion and a metal portion. For example, according to an embodiment, the support member is a direct copper bond (DCB) comprising a ceramic plate and a copper layer bonded to one side thereof (or to its opposite sides). The bond between the copper layer and the ceramic plate can be provided by a copper-oxygen eutectic, which forms a bond between the copper layer and the ceramic plate. The copper-oxygen eutectic can be formed by heating the copper layer and the ceramic plate to a controlled temperature in a nitrogen atmosphere containing 20-40 ppm of oxygen. The copper layer bonded to the ceramic can be formed into a pattern before being bonded to the ceramic plate (for example, the copper layer can be pre-formed (for example, stamped)) or can be structured (for example, by etching). According to an embodiment, forming the copper layer on the ceramic plate includes applying a seed layer and electroplating the seed layer. The ceramic material can include, for example, one or more of aluminum oxide (Al2O3), aluminum nitride (AlN), or beryllium oxide (BeO). The copper layer may have a thickness in the range between 200 micrometers (μm) and 300 μm and may be electroplated using, for example, nickel, a nickel alloy, aluminum nickel, or aluminum.

[0052] According to an embodiment, the conductive trace includes a first end, and the current path includes a second end, wherein the first and second ends define a distance (minimum spacing) between the conductive trace and the current path. According to another embodiment, the first end, the second end, and the sensing device are located at different levels in a direction perpendicular to a main surface of the sensing device. According to an embodiment, the first end is located at a level between the sensing device and the second end. According to another embodiment, the second end is located at a level between the sensing device and the first end.

[0053] According to another embodiment, the first end portion is located at a level below the sensing device, for example, at a level between the sensing device and the current path. In this application, the term "level" may specifically refer to a distance from the bottom surface of the package. According to another embodiment, the first end portion is located at a level below the current path.

[0054] According to an embodiment, the conductive trace includes a raised portion spaced apart from the sensing device. For example, the first end portion may be located at a level below the level of the raised portion. This allows the raised portion to be exposed from the seal while the first end portion is located within the seal. This may allow the conductive trace to be securely attached to the seal.

[0055] According to an embodiment, the relative position of the current path in the conductive trace is determined by the three-dimensional shape of the respective lead frame portion.The shape of the respective lead frame may be obtained by bending the lead frame.

[0056] According to an embodiment, the package further comprises a bonding wire electrically connecting the conductive trace and the contact pad.Thus, in the method of manufacturing the package, electrically connecting the contact pad to the conductive trace may comprise providing a bonding wire between the contact pad and the conductive trace.

[0057] The bonding wire can have the shape of a round wire or a flat ribbon, so that the bonding wire can also be designed as a bonding ribbon. Establishing a connection via one or more bonding wires is a simple process and can be achieved with bonding wires made of copper and / or aluminum.

[0058] Other electrical connections are possible depending on the geometry of the conductive traces relative to the contact pads.

[0059] According to an embodiment, the current path is at least partially surrounded by a seal.

[0060] According to another embodiment, the current path includes an exposed portion forming a portion of an outer surface of the package. In other words, according to an embodiment, the lead frame forming the current path may be shaped to expose the pad.

[0061] According to an embodiment, the sensing device comprises at least one Hall sensor, in particular at least two Hall sensors.

[0062] According to another embodiment, the sensing device comprises at least one magnetoresistive sensor, in particular at least two magnetoresistive sensors.

[0063] Two or more sensors (Hall sensors and / or magnetoresistive sensors) offer the advantage that their signals can be combined to provide a differential signal from which the influence of external magnetic fields (independent of the current to be measured and undesirable) has been removed or at least reduced.

[0064] According to an embodiment, a current path is electrically connected to a first set of contact pins; a conductive trace is electrically connected to contact pins of a second set of contact pins; and the first and second sets of contact pins are located on opposite sides of the package. This geometry of the contact pins can facilitate electrical isolation of the current path and electrical connection to the sensing device.

[0065] The current path may have any geometry suitable to provide a suitable current density and hence a suitable magnetic field for the sensor device.

[0066] According to an embodiment, the current path comprises a measuring portion of reduced cross-section; the measuring portion extends between two spaced-apart sides (of the current path). According to an embodiment, the measuring portion is a straight portion of the current path. This can advantageously provide a measuring portion of defined dimensions.

[0067] According to an embodiment, the side portions have a greater thermal mass than the thermal mass of the straight portion, in particular at least two times greater, for example at least four times greater or at least six times greater. According to an embodiment, each side portion is electrically connected to one or more leads (in an embodiment, the leads are also formed by the leadframe, and the measuring portion and the side portions are formed by the leadframe). The relatively large thermal mass of the side portions improves the removal of heat energy from the measuring portion, which in turn allows for higher current density and therefore better sensitivity of the current sensor package.

[0068] According to an embodiment, the length of the measured portion between the side portions is less than the width of the measured portion perpendicular to the length. In other words, the length of the measured portion corresponds to the distance between the side portions bridged by the measured portion. For example, the ratio of the length of the measured portion to its width is in the range between 0.5 and 0.95, for example 0.75.

[0069] According to an embodiment, at least one of the side portions, for example each side portion, comprises a through hole. Due to the larger surface area of ​​the side portion, such a through hole can reduce or prevent the formation of voids in the seal and / or can improve the structural integrity of the side portion and seal combination.

[0070] The above and other objects, features and advantages of the present invention will become apparent upon consideration of the following description and appended claims taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] The accompanying drawings are included to provide a further understanding of the exemplary embodiments of the specification and constitute a part of this specification, and illustrate exemplary embodiments of the subject matter disclosed herein.

[0072] In the attached figure:

[0073] Figure 1 Shown is a cross-sectional view of a current sensor package according to an embodiment of the herein disclosed subject matter.

[0074] Figure 2 Shown is a cross-sectional view of another current sensor package according to an embodiment of the subject matter disclosed herein.

[0075] Figure 3 An embodiment according to the subject matter disclosed herein is shown for Figure 1 Some isolation aspects of the current sensor package.

[0076] Figure 4 Shown is a cross-sectional view of another current sensor package according to an embodiment of the subject matter disclosed herein.

[0077] Figures 5 to 10 Different geometries of current paths (eg current tracks) according to embodiments of the herein disclosed subject matter are shown.

[0078] Figure 11 Shown Figure 6 The current path exemplifies a second geometry and shows a possible position of two Hall sensors.

[0079] Figure 12 Shown Figure 6 The current path exemplifies a second geometry and shows possible locations of two magnetoresistive sensors.

[0080] Figure 13 A lead frame according to an embodiment of the herein disclosed subject matter is shown. DETAILED DESCRIPTION

[0081] The illustrations in the accompanying drawings are schematic and not to scale. In the accompanying drawings, similar elements or elements with similar functions are represented by the same reference numerals or reference numerals that differ from each other only in the first digit. To avoid unnecessary repetition, the description of such similar elements is not repeated in the subsequent drawings.

[0082] Figure 1 A cross-sectional view of a current sensor package 100 is shown according to an embodiment of the herein disclosed subject matter.

[0083] According to an embodiment, package 100 includes a current path 102, such as a current rail. According to another embodiment, package 100 includes a sensing device 104. According to an embodiment, sensor device 104 is a sensor chip including at least one sensor element, such as two sensor elements 106, two Hall sensors, or two magnetoresistive sensors. According to an embodiment, sensing device 104 includes a first main surface 105, wherein at least one sensor element 106 is located in or near first main surface 105. According to an embodiment, first main surface 105 faces away from current path 102. In other words, according to an embodiment, at least one sensor element 106 faces away from current path 102.

[0084] According to an embodiment, the sensing device 104 is spaced apart from the current path 102 by a distance 108. The sensing device 104 includes a contact pad 110 facing away from the current path 102, e.g. Figure 1 The contact pad 110 is electrically connected to the conductive trace 112 by the bonding wire 114. According to an embodiment, the conductive trace 112 is a sensor pin, such as Figure 1 shown.

[0085] According to another embodiment, the package 100 includes a seal 116 that extends continuously without an internal interface between the current path 102 and the sensing device 104. According to an embodiment, the seal 116, the current path 102, and the conductive trace 112 form part of a pre-molded portion to which the sensing device can be attached in a separate manufacturing step (e.g., after curing the seal 116).

[0086] According to an embodiment, the seal 116 extending between the current path 102 and the sensing device 104 electrically isolates the high voltage potential at the current path 102 from the low voltage potential at the conductive trace 112 .

[0087] According to an embodiment, conductive trace 112 includes a first end 118 and current path 102 includes a second end 119, the ends defining a distance 120 between conductive trace 112 and current path 102. According to an embodiment, first end 118 is located at a level 122 below sensing device 104. In other words, first end 118 is spaced apart from a lower major surface 124 of sensing device 104.

[0088] According to an embodiment, second end 119 of current path 102 is located at level 126 between sensing device 104 and first end 118. In other words, second end 119 of current path 102 is spaced a distance 108 from lower major surface 124, and first end 118 is spaced a distance 128 from lower major surface 124 that is greater than distance 108.

[0089] According to an embodiment, conductive trace 112 includes a raised portion 130 spaced apart from sensing device 104. According to an embodiment, bond wire 114 is bonded to conductive trace 112 at raised portion 130 in contact area 132. According to an embodiment, raised portion 130 is exposed relative to seal 116 in contact area 132.

[0090] According to an embodiment, the current path 102 is connected to a first set of contact pins 134 extending from the package 100. According to another embodiment, the conductive trace 112 is electrically connected to contact pins of a second set of contact pins 136 extending from the package 100. According to an embodiment, the first set of contact pins 134 and the second set of contact pins 136 are located on opposite sides of the package 100, e.g., Figure 1 shown.

[0091] According to an embodiment, the seal 116 includes a hole 138 that exposes the conductive trace 112. According to an embodiment, the hole 138 is connected to the support pin ( Figure 1 The support pins (not shown) are raised to support the conductive trace 112 during the formation of the seal 116, particularly during the formation of the seal 116 between the current path 102 and the conductive trace 112. According to an embodiment, the hole 138 is filled with an electrically insulating filler material 139 such as silicone, epoxy, etc. According to an embodiment, the hole 138 is located so that the interface 140 between the seal 116 and the filler material 139 is not between the current path 102 and the sensing device 104 or between the current path 102 and the conductive trace 112.

[0092] According to another embodiment, the seal 116 includes a hole 142 that exposes the current path 102. According to an embodiment, the hole 142 is connected to the support pin ( Figure 1 The support pins (not shown) are raised to support the current path 102 during the formation of the seal 116, particularly during the formation of the seal 116 between the current path 102 and the sensing device 104. According to an embodiment, the hole 142 is filled with an electrically insulating filler material 144 such as silicone, epoxy, etc. According to an embodiment, the hole 142 is located so that the interface 146 between the seal 116 and the filler material 139 is not between the current path 102 and the sensing device 104 or between the current path 102 and the conductive trace 112.

[0093] According to an embodiment, the sensing device 104 is attached to the attachment surface 148 of the encapsulation 116, for example, using a die attach layer 150 (e.g., a die attach film). According to an embodiment, a recess 152 is formed in the encapsulation, and the sensing device 104 and the bonding wire 114 are located in the recess. According to an embodiment, the recess 152 is filled with an insulating filler material 154, such as epoxy, silicone, etc. According to an embodiment, the insulating filler material 154 can be provided to protect the sensing device 104 and / or the bonding wire 114. According to an embodiment, the sensing device 104 is at least partially surrounded by the encapsulation 116 (molded body).

[0094] According to an embodiment, a cover 156 is provided to seal the recess 152 .

[0095] also, Figure 1 Some isolation aspects according to embodiments of the subject matter disclosed herein are shown. Specifically, Figure 1 Further details are shown of the distances 108 , 120 between the high voltage side 160 (including, inter alia, the current path 102 ) and the supply voltage side 162 (the low voltage side, including, inter alia, the conductive traces 112 , the bonding wires 114 , and the sensing device 104 ). Figure 1102 and 104. The figure further illustrates a creepage / clearance distance 164 between the exposed portion of the high voltage side 160 (particularly of the current path 102) and the low voltage side 162 (particularly of the conductive trace 112). Thus, according to embodiments, leakage may occur along the exterior surface of the current sensor package but not along interfaces within the current sensor package (e.g., interfaces within the seal 116, thereby avoiding such interfaces whenever possible / appropriate). In embodiments, at least interfaces between the current path 102 and the conductive trace 112, and between the current path 102 and the sensing device 104, are avoided (i.e., the seal 116 has no interfaces in these areas).

[0096] According to another embodiment, the current sensor package 300 includes a mounting side 163 configured for mounting to a support, eg, a printed circuit board, direct copper soldering, etc. According to an embodiment, the sensor element 106 faces the main surface 105 away from the mounting side 163 .

[0097] Figure 2 A cross-sectional view of another current sensor package 200 is shown according to an embodiment of the subject matter disclosed herein.

[0098] exist Figure 2 In the description, avoid repetition and Figure 1 A description of two elements that are similar or identical. Figure 2 In terms of Figure 1 The description provided for such elements is equally valid.

[0099] According to an embodiment, the conductive trace 112 is a carrier or part of a carrier, in particular a lead finger of a lead frame. According to another embodiment, the sensing device 104 is at least partially attached to the conductive trace 112, for example by a die attach layer 150. In particular, according to an embodiment, the sensing device 104 extends beyond the conductive trace 112 and has a free end 151 located above the current path 102 (spaced from the current path 102). According to another embodiment ( Figure 2 ), the current path 102 is exposed and forms part of the surface of the package 200.

[0100] Instead of bonding wires 114 electrically connecting contact pads 110 and conductive traces 112, through-silicon vias (TSVs) extending through sensing device 104 may be provided. Figure 2 not shown).

[0101] According to an embodiment, seal 116 is provided after positioning current path 102, sensing device 104, and conductive trace 118 and after electrically connecting sensing device 104 to conductive trace 118. According to an embodiment, seal 116 is a molded body, such as Figure 2 shown.

[0102] According to another embodiment, the first end 118 of the conductive trace 112 is located at a level between the sensing device 104 and the second end 119, e.g. Figure 2 shown.

[0103] Figure 3 A cross-sectional view of another current sensor package 300 is shown according to an embodiment of the subject matter disclosed herein.

[0104] The current sensor package 300 is similar to Figure 2 The current sensor package 200 is shown in FIG. , except for the position of the first side relative to the sensing device 104. Specifically, according to an embodiment, the conductive trace 112 includes two opposing first and second sides 158, 159, wherein the sensing device 104 is attached to the first side 158 of the conductive trace 112 and the bonding wire 114 is attached to the second side 159 of the conductive trace 112, e.g., Figure 3 It should be noted that, in contrast to this embodiment, Figure 2 In the current sensor package 200 , the sensing device 104 and the bond wire 114 are both attached to the same side of the conductive trace 112 .

[0105] According to an embodiment, the end 118 of the conductive trace 112 is located at a level between the end 119 of the current path 102 and the sensing device 104, e.g. Figure 3 shown.

[0106] According to another embodiment, the seal 116 does not have any holes that expose the conductive traces 112 or the current paths 102. In other words, according to an embodiment, the seal 116 does not include any holes that expose the conductive traces 112 or the current paths 102. Figure 1 Holes 138, 142 are depicted.

[0107] According to an embodiment, the first main surface 105 of the sensing device 104 (or in other words, the at least one sensor element 106) faces the current path 102. According to another embodiment, the at least one sensor element 106 faces away from the mounting side 163 of the current sensor package 300. The mounting side 163 is configured to be mounted on the support 165.

[0108] Figure 4 A cross-sectional view of another current sensor package 400 is shown according to an embodiment of the subject matter disclosed herein.

[0109] exist Figure 4 In the description, avoid repetition and Figure 1 For the description of the components similar or identical to the components of Figure 4 In terms of Figure 1 The description provided for such elements is equally valid.

[0110] According to an embodiment, the current path 102 includes an exposed portion 166 that forms a portion of an outer surface 168 of the package 400 .

[0111] Figures 5 to 10 Different geometries of current paths 102 (current tracks) according to embodiments of the herein disclosed subject matter are shown.

[0112] Figure 5 An exemplary first geometry 170 of the current path 102 is shown.

[0113] According to an embodiment, current path 102 is a current track. According to an embodiment, current path 102 includes a measuring portion 172 having a reduced cross-section. In other words, if the thickness of the current path is substantially constant, different cross-sections at different locations along the current path can be estimated based on the different lateral dimensions of the current path. According to another embodiment, current path 102 includes two spaced-apart side portions 174. According to another embodiment, measuring portion 172 extends between the two side portions 174.

[0114] According to an embodiment, the measuring portion 172 is a straight portion of the current path 102. According to another embodiment, the side portion 174 has a thermal mass that is greater than the thermal mass of the straight portion, in particular at least twice as great, e.g. Figure 5 According to an embodiment, each side portion 174 is connected to one or more leads 176, such as Figure 5 A lead 176 is shown. Thus, in an embodiment, each side 174 is defined by a measuring portion 172 and a lead 176. According to an embodiment, a length 178 of the measuring portion 172 between the sides 174 is less than a width 180 of the measuring portion perpendicular to the length 178. For example, according to an embodiment, the length 178 is approximately 300 μm and the width 180 is approximately 400 μm, resulting in an overall length 179 of the current path 102 of 4.56 mm.

[0115] Figure 6 An exemplary second geometry 270 of the current path 102 is shown.

[0116] According to an embodiment, each side portion 174 includes a through hole 182, such as Figure 6 According to an embodiment, the through hole 182 has a triangular shape, as shown in FIG. Figure 6 shown.

[0117] Figure 7 An exemplary third geometry 370 of the current path 102 is shown.

[0118] The third geometric shape 370 is similar to Figure 5According to an embodiment, each side is connected to two leads 176, such as Figure 7 shown.

[0119] Figure 8 An exemplary fourth geometry 470 of the current path 102 is shown.

[0120] The fourth geometric shape 470 is similar to the first geometric shape 170 and the third geometric shape 370. According to an embodiment, each side portion 174 is electrically connected to a lead 176 having a width similar to the maximum width of the side portion 174, e.g., Figure 8 For example, according to an embodiment, the maximum width of the lead 176 is in the range of approximately 80% to 120% of the maximum width of the side portion 174. Furthermore, according to an embodiment, a through hole 184 is formed in the lead 176.

[0121] Figure 9 An exemplary fifth geometry 570 of the current path 102 is shown.

[0122] The fifth geometric shape 570 is similar to Figure 7 According to an embodiment, the through hole 182 is formed in the side portion 174, for example, Figure 9 According to an embodiment, the through hole has a circular shape, for example, Figure 9 shown.

[0123] Figure 10 An exemplary sixth geometry 670 of the current path 102 is shown.

[0124] According to an embodiment, the side portion 174 has a generally rectangular shape.

[0125] In short, about Figures 5 to 10 According to an embodiment, the shape of the side portion tapers in a direction from the lead 176 to the measuring portion 172 and has a generally triangular shape, for example, as Figure 5 、 7 , 8 and 9. According to an embodiment, each side portion has a first portion with an increased cross-section and a second portion with an increased cross-section in a direction from the lead 176 to the measuring portion 172, for example, Figure 5 、 6 , 7, 8 and 9. According to another embodiment, the distance between the opposite sides 174 of the current track 102 is increased from the first distance 186 (see Figure 10 ) changes to the length 178 of the measuring portion 172, in particular in a step-wise manner, e.g. Figures 5 to 10 shown.

[0126] Figure 11 Shown Figure 6 An exemplary second geometry 270 of the current path 102 is shown and possible locations of two Hall sensors 188 are illustrated.

[0127] According to an embodiment, the first Hall sensor 188 is located between the two side portions 174 adjacent to (e.g., beside) the measuring portion 172. According to an embodiment, the second Hall sensor 188 is opposite the first Hall sensor 188, and the measuring portion 172 extends between the two sensors 188, e.g., Figure 11 shown.

[0128] Figure 12 Shown Figure 6 FIG. 2 illustrates an exemplary second geometry 270 of the current path 102 and possible locations of two magnetoresistive sensors 190 .

[0129] According to an embodiment, the current path 102 includes a slit 192 between the two side portions 174. According to an embodiment, the first magnetoresistive sensor 190 is located between the slit 192 and the opening 182 of one of the two side portions 174, and the second magnetoresistive sensor 190 is located between the slit 192 and the opening 182 of the other of the two side portions 174, for example. Figure 12 shown.

[0130] Figure 13 Shown is a perspective view of a lead frame 194 according to an embodiment of the subject matter disclosed herein.

[0131] According to an embodiment, the lead frame 194 includes the current path 102, four conductive traces 112, and a connecting portion 196 connecting the current path 102 and the conductive traces 112. After the current sensor package 100 is manufactured based on the lead frame 194 according to an embodiment of the disclosed subject matter, the first group of contact pins 134 (i.e., the leads 176 of the current path 102) and the second group of contact pins 136 (also referred to as the contact pins 136) are connected to the lead frame 194. Figure 1 ) is separated from the connecting portion 196.

[0132] It should be noted that the term "comprising" does not exclude other elements or features, and "a" or "an" does not exclude a plurality. Moreover, elements described in conjunction with different embodiments may be combined. It should also be noted that the reference numerals should not be understood as limiting the scope of the claims. Furthermore, the scope of this application is not intended to be limited to the particular embodiments of the processes, machines, manufactures, and compositions of matter, means, methods, and steps described in the specification. Therefore, the appended claims are intended to include within their scope such processes, machines, manufactures, compositions of matter, means, methods, or steps.

Claims

1. A current sensor package (100, 200, 300), comprising: a current path (102) comprising a measuring portion (172) of reduced cross-section extending between two spaced-apart sides (174); a sensing device (104) spaced apart from the current path (102) and configured to sense a magnetic field generated by a current flowing through the current path (102); The sensing device (104) comprises a sensor element, the sensing device (104) being electrically connected to a conductive trace (112); a seal (116) extending continuously between the current path (102) and the sensing device (104), wherein the seal (116) surrounds the current path (102), wherein the measuring portion is a straight portion of the current path (102); • wherein the side portions (174) have a thermal mass greater than the thermal mass of the straight portion.

2. The package according to claim 1, wherein the sensing device (104) is a sensor chip.

3. The package of claim 1, wherein the seal (116) extends continuously between the current path (102) and the conductive trace (112).

4. The package of claim 2, the conductive trace (112) being a carrier, the sensing device (104) being attached to the carrier.

5. The package of claim 2, the conductive trace (112) being a lead frame (194).

6. The package of any one of claims 1 to 3, the sensing device (104) being attached to the seal (116).

7. The package according to any one of claims 1 to 5, the current path (102) being formed by a metal carrier.

8. The package of claim 7, the current path (102) being formed by a lead frame (194).

9. The package of any one of claims 3 to 5, the seal comprising a hole (138) exposing the conductive trace (112), the hole (138) being filled with an electrically insulating filling material (139).

10. The package according to any one of claims 1 to 5, The conductive trace (112) includes a first end (118), and the current path (102) includes a second end (119), wherein the first end (118) and the second end (119) define a distance (120) between the conductive trace (112) and the current path (102), wherein The first end portion (118), the second end portion (119), and the sensing device (104) are located at different levels in a direction perpendicular to a main surface of the sensing device; wherein the first end (118) is located at a level between the sensing device (104) and the second end (119), or wherein the second end is located at a level between the sensing device and the first end (118).

11. The package of claim 10, the conductive trace (112) comprising a raised portion (130) spaced apart from the sensing device (104).

12. The package of any one of claims 1 to 5, the sensing device further comprising a contact pad, the package further comprising a bonding wire (114) electrically connecting the conductive trace (112) and the contact pad (110).

13. The package according to any one of claims 1 to 5, wherein The current path (102) includes an exposed portion (166) that forms part of an outer surface (168) of the package (300).

14. The package according to any one of claims 1 to 5, wherein The sensing device comprises at least one further sensor element.

15. The package according to any one of claims 1 to 5, wherein Each of the sensor elements of the sensing device is one of a Hall sensor (188) and a magnetoresistive sensor (190), wherein the magnetoresistive sensor is an anisotropic magnetoresistive sensor, a giant magnetoresistive sensor, an ultra-giant magnetoresistive sensor, or a tunnel magnetoresistive sensor.

16. The package according to any one of claims 1 to 5, The current path is electrically connected to a first set of contact pins (134); The conductive trace is electrically connected to a contact pin in a second set of contact pins (136); and The first set of contact pins (134) and the second set of contact pins (136) are located on opposite sides of the package.

17. The package of claim 1, wherein: The thermal mass of the side portions (174) is at least two times greater than the thermal mass of the straight portion.

18. The package of claim 1, wherein: A length (178) of the measuring portion (172) between the side portions (174) is less than a width (180) of the measuring portion (172) perpendicular to the length (178).

19. The package according to claim 17 or 18, wherein Each side portion (174) includes a through hole (182).

20. The package according to any one of claims 1 to 5, wherein The seal (116), the conductive trace (112) and the current path (102) form part of a pre-molded portion, wherein the pre-molded portion includes an attachment surface to which the sensing device (104) is attached.

21. The package according to any one of claims 1 to 5, Also included is a mounting side (163) configured to be mounted to a support (165); The sensor element (106) faces away from the mounting side (163) and / or away from the current path (102).

22. A method of manufacturing a current sensor package, the method comprising: providing a current path (102) comprising a measuring portion (172) of reduced cross-section extending between two spaced-apart sides (174); providing a sensing device (104) configured to sense a magnetic field generated by a current flowing through the current path (102) and comprising a sensor element (106); Positioning the sensing device (104) spaced apart from the current path (102); electrically connecting the sensing device (104) to the conductive trace (112); providing a seal (116) extending continuously between the current path (102) and the sensing device (104), wherein the seal (116) surrounds the current path (102), wherein the measuring portion is a straight portion of the current path (102); • wherein the side portions (174) have a thermal mass greater than the thermal mass of the straight portion.

23. The method according to claim 22, wherein The sensing device (104) is a sensor chip.

24. The method of claim 22, further comprising: ·in, said providing said seal (116) comprises providing said seal over at least a portion of said current path (102); • wherein said positioning said sensing device (104) comprises attaching said sensing device (104) to said seal (116).

25. The method according to claim 22, wherein the conductive trace (112) is a carrier; and ·in, The positioning of the sensing device (104) includes attaching the sensing device (104) to the conductive trace (112); • wherein said providing said seal (116) comprises providing said seal continuously between said current path (102) on the one hand and said sensing device (104) and said conductive trace (112) on the other hand.

26. The method according to claim 25, wherein The conductive trace (112) is a lead frame (194).

27. The method according to any one of claims 22 to 26, wherein: The sensing device includes a contact pad (110); and electrically connecting the sensing device to the conductive trace (112) includes providing a bonding wire (114) and / or a through-silicon via (TSV) between the contact pad (110) and the conductive trace (112).

28. The method according to any one of claims 22 to 26, further comprising: providing a support element for the conductive traces before providing the seal (116); After providing the seal (116) around the conductive trace (112) and the support element, removing the support element, the removed support element leaving a hole (138) in the seal (116); • Filling the hole (138) in the seal (116) with an electrically insulating filler material (139).

29. The method according to any one of claims 22 to 26, wherein: The current sensor package further includes a mounting side (163) configured to be mounted to a support (165); Wherein positioning the sensing device (104) includes positioning the sensor element (106) facing away from the mounting side (163) and / or facing away from the current path (102).

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