ELECTRICAL ASSEMBLY AND METHOD FOR ITS MANUFACTURING

Abstract

An electrical assembly comprises: a circuit carrier; on a first side of the circuit carrier, at least one first electrical, in particular electronic, component mounted thereon and connected to the circuit carrier in a current-conducting or signal-conducting manner; on a second side of the circuit carrier opposite the first side, a second electrical, in particular electronic, component mounted thereon and connected to the circuit carrier in a current-conducting or signal-conducting manner; at least one current-conducting or signal-conducting, in particular metallic, spacer mounted on the second side of the circuit carrier and connected to the circuit carrier in a current-conducting or signal-conducting manner;and a mold housing which encloses the second component and the at least one spacer such that the distal end of each spacer, viewed from the circuit carrier, has a current- or signal-conducting contact surface not covered by the mold housing for contacting from outside the mold housing. A current- or signal-conducting connection exists between the contact surface and a terminal of the second component indirectly via the spacer and the circuit carrier. A method for manufacturing the assembly and specific uses are also described.

Description

[0001] The present invention relates to an electrical assembly, such as a system-in-package (SIP), a method for its manufacture, and a particular use of such an assembly.

[0002] As part of the progressive high integration of electrical, especially electronic, components (e.g. microelectronic components such as integrated circuits or individual components) into electrical, especially electronic, assemblies, more and more different components and possibly other components are integrated into them.

[0003] Particularly in the context of so-called 3D integration, where the components are arranged at least partially vertically on top of each other (e.g., via diestacking), the task of achieving 3D integration often involves implementing complicated wiring, especially rewiring, in order to connect the components integrated in three dimensions with corresponding external connections of the assembly and / or the components to each other in a current- and / or signal-conducting manner.

[0004] US 2016 / 0113115A1 discloses a system-on-package (SoP) module comprising a printed circuit board connecting a first integrated circuit (IC) and a second integrated circuit (IC). The conductors used to attach the second IC to the printed circuit board also allow for electrical testing of the first IC when the SoP module is in a system state.

[0005] US 2019 / 0098802 A1 discloses devices for shielding in electronic assemblies, as well as related methods and devices. In particular, an electronic assembly can comprise a printed circuit board (PCB) with a first surface and a second, opposing surface, and a shield connected to the second surface of the PCB. The PCB can have a hole extending through it, and the shield can extend into the hole toward the first surface.

[0006] US Patent 2014 / 0063764A1 discloses a substrate with an integrated electronic component. It comprises a first substrate and a second substrate electrically connected by a spacer. An electronic component is mounted on the first substrate and positioned between the first and second substrates. An encapsulating resin fills the space between the first and second substrates to encapsulate the electronic component. The spacer comprises a stacked structure of a metal post and a solder ball, stacked in a single direction along the first and second substrates. The spacer further comprises an insulating layer formed on the second substrate that covers one side of the metal post.

[0007] EP 4 192 200 A1 discloses a printed circuit board with at least one first electronic component and one second electronic component. At least one electronic component is located on a front side of the printed circuit board, while at least one other electronic component is arranged on a back side of the printed circuit board. The electronic components may, in particular, be power semiconductors.

[0008] US 6,075,711 A discloses a system and a method for efficiently connecting a plurality of integrated circuits (ICs), thereby improving the electrical performance of the overall system. In one embodiment of the system of the present invention, a plurality of carriers corresponds to a plurality of ICs, and a circuit board has a plurality of board areas for receiving the plurality of ICs. In one embodiment of the method of the present invention, a carrier is provided for each IC in a complex IC. A circuit board with openings is provided, and the ICs are inserted into the circuit board openings with the carriers attached to them.

[0009] It is an object of the invention to provide an improved assembly technique for electrical assemblies in order to enable a high degree of spatial integration of different components within the assembly and protection of these components against external influences, while requiring little space.

[0010] To solve this problem, an electrical assembly and a method for its manufacture are proposed according to the teaching of the independent claims. Furthermore, specific uses of such an assembly are described, in which its advantages can be particularly evident. Various embodiments and further developments of the solution are the subject of the dependent claims. terms

[0011] Some terms used herein to define the present invention are explained in more detail below: The term "electrical component" or simply "component," as used herein, refers to an essential part of an electrical circuit that cannot be further subdivided physically without losing its function. The term denotes (i) a carrier of a physical or electronically realizable property in the form of a real (discrete) electrical component. An electrical component can be composed of individual parts. In particular, voltage sources, resistors, capacitors, inductors, diodes, transistors, and integrated circuits are all examples of electrical components.

[0012] The term "electrical assembly" or simply "assembly," as used herein, refers specifically to a structural and usually also functional unit consisting of integrated and / or discrete and passive electrical components that are electrically and mechanically connected by a wiring network on a circuit carrier (also often referred to as a "wiring carrier"). If an electrical assembly includes at least one active electrical (i.e., electronic) component, such as a transistor or an integrated circuit, it is also referred to as an "electronic assembly." Within an electrical device, the assembly typically forms the next higher hierarchical level after the electrical components.

[0013] The term "circuit carrier," as used herein, refers to a substrate made of an electrically insulating material, equipped with electrical conductors which, together with electrically connected components, form a circuit. Printed circuit boards (PCBs) in particular fall under the term "circuit carrier."

[0014] The term "electrically insulating," as used herein, refers to the property of a non-conductor to not conduct, or to conduct very little, electric current. In particular, materials with an electrical conductivity of less than 10⁻⁵ are considered electrically insulating. -6 S / m or their specific resistance over 10 8 Ω·cm is non-conductor and therefore electrically insulating.

[0015] The term "mounting," as used herein, refers to the fastening and electrical connection of a component to or with the circuit board. Mounting techniques known in the field of electronics include, in particular, surface mounting technology (SMD) and through-hole technology (THT).

[0016] The term "conductive," as used herein, refers to the property of a conductor, such as a conductor track on a circuit board, to conduct electric current (well). In particular, materials or substances which (at 25 °C) have a conductivity σ > 10 4 S / m are classified as electrically conductive or conductors, such as metals.

[0017] The term "signal-conducting," as used herein, refers to the property of a conductor, such as a conductor track on the circuit board, to transmit a signal, in particular an electrical or optical signal, in a materially bound manner. The signal transmission can be based, in particular, on electrical conduction along a conductor or on optical conduction along an optical fiber.

[0018] The term "thermally conductive," as used herein, refers to the property of a material to efficiently transport thermal energy (heat) through thermal diffusion or, equivalently, conduction. Specifically, materials and objects made from them that exhibit a thermal conductivity λ ≥ 10 W / (m·K) are considered good thermal conductors and thus "thermally conductive." Particularly good thermal conductors are generally metals such as copper or aluminum, which typically exhibit thermal conductivities λ ≥ 100 W / (m·K).

[0019] The term "spacer," as used herein, refers to a spacer, also known as a "distance bolt," "spacer rod," "standoff piece," or "spacer holder," designed specifically to ensure that a distance is maintained between two bodies. The spacer is, in particular, electrically conductive and, if applicable, also thermally conductive, solderable, and / or attachable to the circuit board using conventional die-bonding methods, especially by adhesive bonding.

[0020] The term "solder ball," as used herein, refers to an electrically conductive and solderable material, particularly spherical, suitable for establishing electrical contact between a chip package and a circuit carrier (especially a printed circuit board, PCB) or between stacked packages or assemblies, such as in multi-chip modules or assembly combinations. In the latter case, solder balls are also frequently referred to as "microbumps" (µbumps, ubumps) because they are generally significantly smaller than the former. Solder balls can be placed manually or using automated equipment and are usually fixed in place with an adhesive flux. There are also embossed solder balls, which are solder balls that have been embossed, i.e., flattened to resemble a coin, to increase contact reliability.A solder ball does not necessarily have a spherical shape, but can also take on other forms. This can be particularly true for its state after the soldering process and thus the melting of the original solder ball, since it is then usually no longer spherical and may have taken on a flattened or even irregular shape.

[0021] The term "hard-core solder ball," as used herein, refers to a solder ball in which a hard core with a significantly higher melting point is embedded in a soldering compound that melts during the soldering process. This core is essentially dimensionally stable during soldering (apart from thermal expansion). The hard core may contain copper or aluminum, or even be made entirely of these materials. The soldering compound used can be, as is common in the electronics industry, a mixture (alloy) of different metals, with lead, tin, zinc, silver, and copper being particularly frequent choices.

[0022] The term "mold package," as used herein, refers to a housing for one or more electronic components, manufactured using a molding process. Mold packages are particularly common as chip packages for (micro)electronic components, such as integrated circuits.

[0023] Any terms used herein, such as "comprises," "includes," "includes," "features," "has," "with," or any other variant thereof, are intended to cover non-exclusive inclusion. For example, a method or apparatus that includes or features a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent in such method or apparatus.

[0024] Furthermore, unless explicitly stated otherwise, "or" refers to an inclusive "or" and not an exclusive "or". For example, a condition A or B is satisfied by one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0025] The terms "ein" or "eine," as used here, are defined as "one or more." The terms "ein anderer" and "ein Weitere," as well as any other variant thereof, are to be understood as "at least one more."

[0026] The term "plural", as it may be used here, is to be understood in the sense of "two or more".

[0027] The terms "first", "second", "third", and similar terms in the description and claims are used to distinguish between similar or otherwise identically named elements and not necessarily to describe a sequential, spatial, or chronological order. It is understood that the terms used in this way are interchangeable under suitable circumstances and that the embodiments of the solution described herein may also function in orders other than those described or illustrated here.

[0028] The terms "configured" or "set up" to perform a specific function (and their respective variations), as used here, mean that a device or component thereof already exists in a configuration or setting capable of performing the function, or at least is adjustable—i.e., configurable—so that it can perform the function after appropriate adjustment. Configuration can be achieved, for example, by adjusting process parameters or by using switches or similar devices to activate or deactivate functionalities or settings. In particular, the device may have several predefined configurations or operating modes, allowing configuration by selecting one of these.

[0029] A first aspect of the solution presented here concerns an electrical assembly comprising: (i) a circuit carrier, in particular a printed circuit board (PCB); (ii) on a first side of the circuit carrier at least one first electrical, in particular electronic, component mounted thereon and connected to the circuit carrier in a current- or signal-conducting manner; (iii) on a second side of the circuit carrier opposite the first side, a second electrical, in particular electronic, component mounted thereon and connected to the circuit carrier in a current- or signal-conducting manner; (iv) at least one current- or signal-conducting, in particular metallic, spacer mounted on the second side of the circuit carrier and connected to the circuit carrier in a current- or signal-conducting manner; and (v) a mold housing, in particular a hermetically sealed one, which encloses the second component and the at least one spacer in such a way that the respective distal end of each spacer, as seen from the circuit carrier, has a current- or signal-conducting contact surface not covered by the mold housing for contacting from outside the mold housing.

[0030] In this case, a current- or signal-conducting connection exists between the contact surface and a terminal of the second component indirectly via the spacer and the circuit carrier.

[0031] In the aforementioned electrical assembly, internal rewiring takes place, allowing it to require only a small installation space for integrating the various components and enabling the circuit board to be used for double-sided assembly, for example with SMD or chip components. This allows for a high integration density.

[0032] Furthermore, this configuration also allows for the arrangement of the aforementioned mold housing, which ensures effective protection of the components and wiring located on at least one side of the circuit carrier against external influences.

[0033] Since the contact surfaces remain at least partially uncovered by the mold housing material, they serve as connection pads for the electrical connection of the assembly. Solder connections can be used for this purpose, in particular to connect the assembly to other components, especially those external to the assembly, for electrical or signal transmission. Furthermore, multiple assemblies can be stacked on top of each other and electrically connected via the contact surfaces to form a more complex assembly.

[0034] The design of the assembly also allows for a high degree of flexibility in terms of the assembly's design, as both the arrangement of the components on the circuit carrier and the arrangement of the spacers can be highly variable during its design.

[0035] Furthermore, the second component is arranged rotated relative to the circuit carrier with respect to an axis of rotation defined orthogonally to the second side of the circuit carrier such that the respective perpendicular projection of at least one outer edge, in particular all outer edges, of the second component is not parallel to any of the outer edges of the second side of the circuit carrier. For example, this is the case if the circuit carrier has a rectangular plate shape and the second component also has a rectangular plate shape, so that the main surfaces of the two plate shapes are parallel but rotated relative to each other by an angle of rotation other than 0°, 90°, or a multiple of 90°. This allows the contiguous surface areas available on the circuit carrier for placing the spacer(s) to increase or decrease.to take on a form that allows greater variability regarding the placement of the spacers than would be the case with a parallel orientation, i.e., a rotation angle of 0°.

[0036] The number of spacers is at least three, arranged non-linearly such that they define a bounded virtual area of ​​non-zero size between them, parallel to or lying on the second side of the circuit carrier. An orthogonal projection of the second component intersects the perimeter of this virtual area but does not touch the spacers. This allows the component to be placed between the spacers without coming into direct contact with them, while maintaining a high degree of spatial flexibility in the arrangement of the spacers on the circuit carrier. Overall, this enables a particularly space-saving and flexible design of the assembly with regard to the arrangement of the spacers.

[0037] The following describes various exemplary embodiments of the assembly, which, unless expressly excluded or technically impossible, can be combined with each other and with the other aspects of the present solution described below.

[0038] In some embodiments, the assembly further comprises a hard-core solder ball for each spacer to create a solder joint between the spacer's contact surface and a mating surface, particularly one external to the assembly. The hard-core solder ball is fixed to the contact surface of the respective spacer in a current- or signal-conducting manner. The contact surface thus serves as a solder pad for the hard-core solder ball. The use of hard-core solder balls instead of conventional solder balls without a hard core allows for the reliable and effortless creation of a predefined solder joint height, largely determined by the size (height) of the hard core. This enables a uniform soldering distance to other components.

[0039] The hard core of the soldering ball can be made entirely or partially of copper or a copper alloy. This results in particularly high electrical conductivity and good material compatibility with the contact surfaces, especially when using spacers that contain copper or are even made entirely of copper.

[0040] The (respective) hard-core solder ball can be fixed to the contact surface of the respective spacer, in particular by means of a soldering, sintering, or adhesive bond. This can especially refer to fixing the hard-core solder ball to the contact surface before carrying out a subsequent soldering process involving the hard-core solder ball.

[0041] In some embodiments, the assembly further comprises a functional unit indirectly connected to the circuit carrier via the spacers, either for current or signal conduction. This functional unit has a corresponding mating surface with respect to at least one spacer and is electrically connected to that spacer via a current or signal conduction connection. This allows the functionality of the assembly to be expanded. In particular, it is possible to iteratively integrate a plurality of functional units successively into the assembly in this way, thus enabling the assembly's functionality to be variably defined.

[0042] In particular, the functional unit can include at least one sensor or actuator, or at least a sub-assembly containing a sensor or actuator. The assembly thus possesses sensor or actuator functionality and can therefore be used as a highly integrated sensor or actuator assembly requiring minimal installation space. Various sensor types are conceivable, especially pressure or temperature sensors. Piezoelectric actuators, such as sound transducers, are particularly suitable as actuators.

[0043] The second component can, in particular, include an integrated circuit for at least partial processing of sensor signals that are indirectly transmitted to the second component by the sensor or actuator, or the sub-assembly, via at least one electrical connection, at least one spacer, and the circuit carrier. Thus, the assembly can function as an "intelligent sensor assembly" and / or "actuator assembly," which, in the case of a sensor, can deliver not only raw sensor data but also at least partially processed sensor data. In the case of an actuator, the assembly can, for example, receive input signals and derive control signals from them to actuate the actuator. The corresponding data processing capacity can therefore be saved elsewhere.

[0044] In some embodiments, at least one spacer is connected to the circuit carrier via a current- or signal-conducting soldered joint, sintered joint, or adhesive bond. The choice of connection type can depend, in particular, on the respective materials of the circuit carrier conductors and the spacer, especially with regard to optimizing mechanical adhesion, minimizing electrical resistance, ensuring the reliability and corrosion resistance of the connection, and / or simplifying the manufacturing process.

[0045] In some embodiments, the assembly further comprises a heat sink that is thermally conductive, either directly or indirectly (i.e., via one or more intervening, also thermally conductive bodies) connected to the contact surface of at least one of the spacers. In particular, such an indirect connection may include a solder ball, especially a hard-core solder ball, or may even be solely achieved by such a solder ball. Thus, any waste heat generated in the assembly during its operation, such as that which may occur during the operation of an active component (e.g., a transistor), an integrated circuit, or an electrical resistor, can be effectively dissipated from the assembly and released into its surroundings to maintain the assembly within a target temperature range.

[0046] In some embodiments, the assembly further comprises a metallic shielding element or an antenna that is electrically connected directly or indirectly (i.e., via one or more intervening, also electrically conductive bodies) to the contact surface of at least one of the spacers. In particular, such an indirect connection may include a solder ball, especially a hard-core solder ball, or may even be solely achieved by such a connection. These embodiments are particularly advantageous when the assembly has a wireless communication interface, such as a radio interface, which uses the antenna to transmit or receive wireless signals, or when the EMC resistance of the assembly is improved by means of the shielding.

[0047] In some embodiments, the first component has a connector for the power or signal connection of the assembly. This allows the assembly to be easily disconnected, particularly without tools, as a pluggable unit with another component, such as another assembly or a system board (also called a "system board" or "mother board"), using a matching mating connector. In addition to or instead of the connector, other physical interface units are also conceivable, such as electrical spring contacts, screw terminals, or clamp connectors, etc.

[0048] A second aspect of the present solution concerns a method for manufacturing an electronic assembly according to the first aspect. The method exhibits: (i) Mounting at least one first electrical component on a first side of a circuit carrier, establishing a current- or signal-conducting connection between the first component and the circuit carrier; (ii) Mounting at least one second electrical component on a second side of the circuit carrier opposite the first side, establishing a current- or signal-conducting connection between the second component and the circuit carrier; (iii) Mounting at least one current- or signal-conducting spacer on the second side of the circuit carrier, establishing a current- or signal-conducting connection between the spacer and the circuit carrier; and (iv) Enclosing at least the second component and the at least one spacer with a mold housing, such that the mold housing encloses the second component and the at least one spacer in such a way that the distal end of each spacer, as seen from the circuit carrier, has a current- or signal-conducting contact surface not covered by the mold housing for contacting from outside the mold housing.

[0049] The assembly is manufactured in such a way that: - a current- or signal-conducting connection is established indirectly between the contact surface and a terminal of the second component via the spacer and the circuit carrier. - with respect to an axis of rotation defined orthogonally to the second side of the circuit carrier (2), the second component is arranged rotated relative to the circuit carrier (2) such that the respective perpendicular projection of at least one outer edge of the second component is not parallel to any of the outer edges of the second side of the circuit carrier (2); - the number of spacers (5) is at least three; - the spacers (5) are arranged non-linearly such that they span between them a bounded virtual area of ​​non-zero size that is parallel to or located on the second side of the circuit carrier (2); and - an orthogonal projection of the second building element intersects the perimeter of this virtual surface, but does not touch the spacers (5)

[0050] According to some embodiments of the method, the encapsulation while leaving at least one contact surface exposed can be achieved using a film-assisted molding process, in which each contact surface is covered by a pressurized film during the molding process to prevent coverage with the molding compound used for molding. This allows for effective and, due to the possibility of parallel processing, also efficient production of the assembly while leaving at least one contact surface exposed.

[0051] A third aspect of the present solution concerns the use of the electrical assembly described in the first aspect as a component in a device or system designed as an industrial plant, vehicle, medical device, aircraft, or as a component of one of the aforementioned devices or systems. Particularly in applications involving such devices or systems, the advantages of the solution-based assembly, especially its high achievable integration density combined with the protection of the components from external influences that cannot be ruled out due to the nature of the application, are of particular importance.

[0052] The features and advantages explained in relation to the first aspect of the solution also apply accordingly to the other aspects of the solution.

[0053] Further advantages, features, and application possibilities of the present solution will become apparent from the following detailed description in conjunction with the figures. The assemblies shown in the figures each represent different embodiments, as described in more detail below, although the rotation of the second component relative to the circuit carrier as defined in claim 1 is not shown.

[0054] This shows Fig. 1 a side sectional view of a first exemplary embodiment of an electrical assembly, with a plug connector as the first component and an integrated circuit as the second component (other components not shown); Fig. 2 a lateral sectional view of a second exemplary embodiment of an electrical assembly, in which the first embodiment is supplemented by a functional unit which is connected to the spacers of the assembly via solder connections; Fig. 3 a lateral sectional view of a third exemplary embodiment of an electrical assembly, in which the second embodiment is supplemented by a second mold housing for enclosing the functional unit and its connections to the spacers; Fig. 4 a side sectional view of a fourth exemplary embodiment of an electrical assembly in which a further sub-assembly is added by means of a further 3D integration using a package-on-package (PoP) technology; Fig. 5 a lateral sectional view of a fifth exemplary embodiment of an electrical assembly in which a heat sink connected to the spacers in a thermally conductive manner is provided as a functional unit; Fig. 6 a view of the second side of the circuit carrier before its housing; Fig. 7 a top view of the first side of the circuit carrier of the assembly opposite the second side according to any one of the Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. 5 before its enclosure; Fig. 8 a perspective view of an exemplary embodiment of a spacer; and Fig. 9 a flowchart to illustrate an embodiment of the method for manufacturing an assembly, in particular the assembly according to Fig. 1.

[0055] In the figures, identical reference symbols denote identical, similar, or corresponding elements. Elements depicted in the figures are not necessarily shown to scale. Rather, the various elements depicted in the figures are represented in such a way that their function and general purpose are understandable to a person skilled in the art. Connections and couplings between functional units and elements shown in the figures can, unless expressly stated otherwise, also be implemented as indirect connections or couplings. Unless otherwise specified in detail, functional units can, in particular, be implemented as hardware, software, or a combination of hardware and software.

[0056] If the following text refers to a "step" or "steps" of the procedure, this does not mean that the associated action must necessarily take place in a single, continuous process. Rather, it is also possible that a "step" is composed of several individual processes within the framework of a procedure and thus corresponds to a sub-process of the procedure.

[0057] Fig. Figure 1 illustrates a first exemplary embodiment of a solution-oriented electrical assembly 1 in a side sectional view. On a circuit carrier 2, such as a printed circuit board (PCB) or a ceramic substrate on which conductive traces are laid down or embedded to form a circuit, a first component 3 is mounted on a first side of the circuit carrier 2. In this example, the first component 3 can be an interface element, in particular a wireless data interface unit (e.g., based on one or more of the following technologies: Bluetooth, NFC, UWB, WLAN, or mobile communications), or a connector (e.g., plug or socket). In addition, further first components 3 can also be mounted on the first side of the circuit carrier (in Fig. (1 not shown for the sake of simplicity).

[0058] On the second side of the circuit carrier 2, opposite the first side, an integrated circuit is mounted as the second component 4. Further (second) components may also be mounted on the second side, in particular so-called SMD components (in Fig. 1 also not shown).

[0059] All components 3 and 4 are connected to the conductor tracks in a current- or signal-conducting manner, so that the conductor tracks with components 3 and 4 respectively form a circuit.

[0060] Additionally, several spacers 5 are mounted on the second side of the circuit carrier 2. Each spacer is made of a highly conductive material, such as copper, aluminum, or alloys thereof, and thus each establishes a current- or signal-conducting connection to a corresponding terminal on one of the conductor tracks of the circuit carrier 2. The connection of the spacers 5 to the circuit carrier 2 can be formed, in particular, by means of a current- or signal-conducting soldered joint, sintered joint, or adhesive bond.

[0061] At the distal ends of the spacers 5, as viewed from the circuit carrier 2, i.e., at the end faces facing away from the circuit carrier 2, there are contact surfaces 5a of the respective spacer. The contact surfaces 5a can, in particular, be flat, as shown. A solder ball 6 is applied to each of the contact surfaces 5a, by means of which the assembly 1 can be connected to a counterpart, e.g., a solderable contact point on another component (in particular another circuit carrier or another assembly), by forming a solder connection.

[0062] In the present example, the solder balls 6 are each designed as hard-core solder balls, i.e., a hard, electrically conductive core (hereinafter referred to as "hard core") 6a is embedded in a solder compound (solder) 6b in the solder ball 6. The melting temperature of the hard core is significantly higher than that of the solder compound 6b, so that when the solder compound 6b melts during the soldering process, the hard core 6a remains essentially unchanged, in particular (apart from any heat-induced expansion) retaining its shape. An advantage of this type of solder ball 6 is that, during soldering, a distance between the two surfaces to be joined by the solder joint can be precisely set by the diameter of the hard core 6a.

[0063] The hard-core solder balls 6 can be fixed to the contact surface 5a of the respective spacer 5, in particular by means of a sintered or adhesive bond, so that they can be attached "cold", i.e., without melting. Alternatively, or in combination, a soldered connection is also possible.

[0064] Furthermore, assembly 1 has a mold housing 7, which connects to the second side of the circuit carrier and hermetically encapsulates the second component(s) 4 and the spacers 5, except for their contact surfaces. The solder balls 6 are also located outside the mold housing.

[0065] In the present example, if the first component 3 is designed as an interface element, in particular a connector, the assembly 1 can be reversibly detached, in particular reversibly detached without tools, connected to other components, and permanently connected to one or more other components via the solder balls 6 by means of solder joints. The circuit carrier 2 provides a rewiring level between, on the one hand, the first and second components 3, 4, and, on the other hand, the spacers and the solder balls arranged thereon.

[0066] The integrated circuit 4 can be connected to the circuit carrier 2 via corresponding connections, either by means of a wire bonding process or a flip-chip technology, and can be additionally mechanically fastened to the circuit carrier 2 by means of a die-bonding connection, e.g., an adhesive bond. The same applies to the connector 3.

[0067] In Fig. Figure 2 shows a second embodiment of assembly 1, which consists of the one from Fig. 1. This is evident from the fact that a further component, hereinafter referred to as functional unit 8, is electrically connected to the contact surfaces of the spacers 5 by means of a solder connection mediated by the solder balls 6. The functional unit 8 can be of various types. In particular, it can be another electrical assembly, a single integrated circuit, an electrical shield (e.g., for EMC shielding purposes), an antenna or a heat sink, or a sensor (or a sensor assembly) or an actuator (or an actuator assembly). For example, the functional unit 8 can include a pressure or temperature sensor and / or an electromechanical actuator, such as a piezoelectric actuator (e.g., a sound transducer or microphone). Other functions or configurations of the functional unit 8 are also conceivable.

[0068] Insofar as the functional unit 8 serves as a signal source or signal receiver, one or more of the first and / or second components 3 and 4, respectively, can be configured as signal processing components. In the present example, this can be, in particular, the second component 4 shown, which is configured as an integrated circuit. Thus, for example, raw sensor data generated by the functional unit 8 or actuator control data to be transmitted to the functional unit 8 can be processed within the assembly 1.

[0069] As in Fig. As can be seen in Figure 2, the original solder balls 6 have changed in their respective shapes after the solder joints have been made, since the solder mass 6b redistributed itself after melting during soldering, and the original spherical shape of the solder ball 6 was lost. Due to the hard cores 6a, a predefined distance is maintained between the contact surfaces of the spacers 5 on the one hand and the corresponding associated connection pads 9 of the functional unit 8 on the other, despite and because of the melting process.

[0070] Fig. 3 represents a further embodiment, a further development of assembly 1. Fig. Figure 2 shows a further mold housing 10 added to the assembly 1 for encapsulating (enclosing) the functional unit and the soldered connections to the spacers 5. This also protects them from unwanted external influences, provided that in the case of a functional unit 8 that requires direct interaction with the environment, this must be ensured, for example by a corresponding opening (not shown) in the mold housing 10 (e.g., in the case of pressure sensors or in the case of piezo actuators, in each case requiring direct interaction with a medium surrounding the assembly, e.g., ambient air).

[0071] It is also conceivable to add further components, similar to functional unit 8, to assembly 1 in a comparable iterative manner (not illustrated). Functional unit 8 can, in particular, have corresponding electrical connections, such as additional connection pads, on its side facing away from circuit carrier 2, by means of which the electrical (and possibly also mechanical) connection to the respective additional component is or can be established.

[0072] Fig. Figure 4 shows a further embodiment that can be used for further 3D integration. Here, a package-on-package technology is used to supplement a first assembly 1, here designated as assembly 1a for clarity, with a further assembly 1b, which can be constructed analogously to assembly 1 according to one of the other figures. In the supplemented assembly 1b, the component 3 is designed with a sufficiently low profile to allow the close stacking of assemblies 1a and 1b. For this purpose, it can even be at least partially embedded in the circuit carrier 2 of assembly 1b. However, the component 3 in assembly 1b can also be omitted. These different options are illustrated by the use of a dashed outline for the component 3.

[0073] Fig. Figure 5 shows another exemplary embodiment of the assembly 1, in which the functional unit 8 is specifically designed as a heat sink 8a. Instead of the aforementioned and also possible indirect connection of the functional unit 8 to the spacers 5 by means of soldered connections, another possible, more direct form of connection is shown here by way of example, in which the heat sink 8a is coupled to the contact surfaces of the spacers either directly or by means of a thermally conductive adhesive or sintered connection.

[0074] Fig. Figure 6 shows a top view of the second side of the populated circuit carrier 2 of the assembly 1 according to Fig. 1, Fig. 2, Fig. 3 or Fig. 4, before the manufacture of the mold housing 7. The second component 4, which is given here by way of example by an integrated circuit with a rectangular perimeter, is aligned here so that its edges are aligned parallel to corresponding edges of the circuit carrier 2.

[0075] Alternatively, it is also conceivable to arrange the second component 4, or specifically the integrated circuit, rotated relative to the circuit carrier. Specifically, the second component 4 can be rotated with respect to an axis of rotation defined orthogonal to the second side of the circuit carrier 2 (i.e., one perpendicular to the other side). Fig. The second component 4 (6 axis perpendicular to the plane of the drawing) is arranged rotated relative to the circuit carrier 2 such that the respective orthogonal projection of at least one outer edge, in this case all outer edges, of the second component 4 is not parallel to any of the outer edges of the second side of the circuit carrier 2. In this way, relatively large, approximately triangular sub-areas are obtained on the second side of the circuit carrier 2, which are available for the placement of the spacers 5 and further second components 11 (in particular SMD components).

[0076] The integrated circuit of component 4 is shown here as an example connected by wire bonding via bond wires 12 running from pads 9 on the integrated circuit to corresponding connection points on the second side of the circuit carrier 2, and thus electrically connected to the circuit supported by the circuit carrier. Alternatively, a flip-chip connection of the integrated circuit is also conceivable, for which it can, in particular, have a ball grid array on its side facing the circuit carrier.

[0077] In assembly group 1 from Fig. In the case of 6, the number of spacers 5 is six, where the spacers 5 are arranged non-linearly such that they span between each other a bounded virtual area of ​​non-zero size, parallel to or lying on the second side of the circuit carrier 2. This is illustrated by the dashed lines. An orthogonal projection of the second component 4 (corresponding in the Fig. 6 of the area occupied by the building element 4) lies in Fig. 6 within the perimeter of this virtual surface (i.e., the surface spanned by the dashed lines) and does not touch the spacers 5. However, it is also conceivable, particularly if the second component 4 is opposite the one in Fig. The arrangement shown in Figure 6 is rotated about an axis of rotation orthogonal to the plane of the drawing, such that the orthogonal projection of the second component 4 intersects the dashed line without touching the spacers 5.

[0078] Fig. Figure 7 shows a top view of the first side of the circuit carrier 2 of the assembly, opposite the second side, according to Fig. 1, Fig. 2, Fig. 3 or Fig. 4 before its housing. The first component 3, the aforementioned interface unit, is centrally located here. In the present example, spacers 5 for mounting and connecting an additional assembly (e.g., according to a PoP technology, as exemplified in Fig. (4 illustrated) Contact pads 13 are formed. In particular, they can extend through the circuit carrier 2 and be electrically connected to the spacers attached on the opposite side of it, thus enabling through-hole plated.

[0079] Fig. Figure 8 illustrates an exemplary embodiment of the aforementioned spacer 5, in which the spacer 5 is essentially disc- or coin-shaped.

[0080] Fig. Figure 9 illustrates an embodiment of a solution-oriented method 20 for manufacturing an assembly 1, in particular the assembly according to Fig. 1.

[0081] In step 21 of process 20, a circuit carrier 2 is provided (or manufactured within process 20 itself) which carries a circuit (in particular, associated connection surfaces for electrical components and conductor tracks connected to these connection surfaces). In particular, the circuit carrier 2 is or is manufactured such that it has first connection areas arranged accordingly for mounting spacers 5, which are connected via the conductor tracks to corresponding second connection areas arranged for mounting at least one second component 4, thus conducting current or signals.

[0082] In a further step 22, at least one first component 3 is mounted on a first side of the circuit carrier, and the associated electrical connections of the first component 3 with associated connection points on the circuit carrier 2 are made. The connections can be, in particular, soldered connections.

[0083] In a further step 23, at least one second component 4 is mounted on a second side of the circuit carrier opposite the first side, and the associated electrical connections of the second component 4 are made with corresponding connection points on the circuit carrier 2. Here too, the connections can be, in particular, soldered connections.

[0084] In a further step 24, at least one spacer 5 is mounted on the second side of the circuit carrier, with each spacer 5 being connected to corresponding terminals on the circuit carrier 2. These connections can again be soldered connections. Electrically conductive sintered or adhesive connections are also possible, either additionally or instead.

[0085] Now, within the framework of a molding process, a mold housing 7 can be formed on the second side of the circuit carrier. In principle, another mold housing can also be formed on the first side of the circuit carrier. It is even conceivable that the entire circuit carrier 2, i.e., both sides, is encapsulated by a single mold housing.

[0086] Here, the molding is advantageously carried out using a film-assisted molding process, which is characterized by the fact that the mold is lined, at least partially, with a thin film before the introduction of the molding compound. This film covers the contact surfaces at the distal ends of the spacers 5, so that these are not covered by the molding compound during the subsequent molding process and thus remain freely accessible in the finished mold housing for the production of the respective electrical contacts. REFERENCE MARK LIST 1 assembly 2 circuit carriers 3. First component, connector 4. Second component, integrated circuit (chip) 5 spacers 5a Contact surfaces on the distal end faces of the spacers 6 solder balls, designed as hard-core solder balls 6a Hard core, in particular copper core, of the solder ball 6 6b Solder compound of the solder ball 6 7 (first) mold housing 8 Functional unit 8a Heat sink as an embodiment for the functional unit 9 pads on the functional unit 10 Second mold housing for functional unit 8 11 SMD components 12 connecting wires for wire bonding 13 Contact pads on circuit carrier for spacer connection 20 methods for manufacturing an electrical assembly 21-26 steps of the procedure

Claims

[1] Electrical assembly (1) comprising: a circuit carrier (2); on a first side of the circuit carrier (2) at least one first electrical component (3) mounted thereon and connected to the circuit carrier (2) in a current- or signal-conducting manner; on a second side of the circuit carrier (2) opposite the first side, a second electrical component (4) is mounted thereon and connected to the circuit carrier (2) in a current-conducting or signal-conducting manner; at least one current-conducting or signal-conducting spacer (5) is mounted on the second side of the circuit carrier (2) and connected to the circuit carrier (2) in a current-conducting or signal-conducting manner; and a mold housing (7) which encloses the second component (4) and the at least one spacer (5) in such a way that the respective distal end of each spacer (5) as seen from the circuit carrier (2) has a current- or signal-conducting contact surface not covered by the mold housing (7) for contacting from outside the mold housing (7); where: a current- or signal-conducting connection exists between the contact surface and a terminal of the second component (4) indirectly via the spacer (5) and the circuit carrier (2); with respect to an axis of rotation defined orthogonally to the second side of the circuit carrier (2), the second component (4) is arranged rotated relative to the circuit carrier (2) such that the respective perpendicular projection of at least one outer edge of the second component (4) is not parallel to any of the outer edges of the second side of the circuit carrier (2); the number of spacers (5) is at least three; the spacers (5) are arranged non-linearly such that they span between them a bounded virtual area of ​​non-zero size that is parallel to or located on the second side of the circuit carrier (2); and an orthogonal projection of the second component (4) intersects the perimeter of this virtual surface, but does not touch the spacers (5). [2] Assembly (1) according to claim 1, further comprising a hard-core solder ball (6) for each spacer (5) for producing a soldered connection between the contact surface of the spacer (5) and a counter surface, wherein the hard-core solder ball (6) is fixed on the contact surface of the respective spacer (5) in a current- or signal-conducting manner. [3] Assembly (1) according to claim 2, wherein the hard core solder ball (6) is fixed to the contact surface of the respective spacer (5) by means of a sintered or adhesive bond. [4] Assembly (1) according to one of claims 2 or 3, wherein a hard core (6a) of the hard core soldering ball (6) is made entirely or partially of copper or a copper alloy. [5] Assembly (1) according to one of the preceding claims, further comprising a functional unit (8) indirectly connected to the circuit carrier (2) via the spacers (5) in a current- or signal-conducting manner, which has the corresponding counter surface at least with respect to one spacer (5) and is connected to this spacer (5) in a current- or signal-conducting manner via an electrical connection. [6] Assembly (1) according to claim 5, wherein the functional unit (8) comprises at least one sensor or actuator, or at least one sub-assembly containing a sensor or actuator. [7] Assembly (1) according to claim 6, wherein the second component (4) has an integrated circuit for at least partial processing of sensor signals that can be indirectly transmitted to the second component by the sensor or sensor assembly via the at least one electrical connection, the at least one spacer (5) and the circuit carrier (2). [8] Assembly (1) according to one of the preceding claims, wherein the at least one spacer (5) is connected to the circuit carrier (2) via a current- or signal-conducting soldered connection, sintered connection or adhesive connection. [9] Assembly (1) according to one of the preceding claims, further comprising a heat sink (8a) which is thermally connected directly or indirectly to the contact surface of at least one of the spacers (5). [10] Assembly (1) according to one of the preceding claims, further comprising a metallic shielding element or an antenna which is or is electrically connected directly or indirectly to the contact surface of at least one of the spacers (5). [11] Assembly (1) according to one of the preceding claims, wherein the first component (3) has a connector for the power or signal connection of the assembly (1). [12] Method (20) for manufacturing an electronic assembly (1) according to any one of the preceding claims, wherein the method (20) comprises: Mounting (22) at least one first electrical component (3) on a first side of a circuit carrier (2), creating a current- or signal-conducting connection between the first component (3) and the circuit carrier (2); Mounting (23) at least one second electrical component (4) on a second side of the circuit carrier (2) opposite the first side, establishing a current- or signal-conducting connection between the second component (4) and the circuit carrier (2); Mounting (24) at least one current- or signal-conducting spacer (5) on the second side of the circuit carrier (2) creating a current- or signal-conducting connection between the respective spacer (5) and the circuit carrier (2); and Enclosing (26) at least the second component (4) and the at least one spacer (5) with a mold housing (7) such that the mold housing encloses the second component (4) and the at least one spacer (5) in such a way that the respective distal end of each spacer (5) as seen from the circuit carrier (2) has a current- or signal-conducting contact surface not covered by the mold housing (7) for contacting from outside the mold housing (7); wherein the assembly (1) is manufactured such that: a current- or signal-conducting connection is established between the contact surface and a terminal of the second component (4) indirectly via the spacer (5) and the circuit carrier (2); with respect to an axis of rotation defined orthogonally to the second side of the circuit carrier (2), the second component (4) is arranged rotated relative to the circuit carrier (2) such that the respective perpendicular projection of at least one outer edge of the second component (4) is not parallel to any of the outer edges of the second side of the circuit carrier (2); the number of spacers (5) is at least three; the spacers (5) are arranged non-linearly such that they span between them a bounded virtual area of ​​non-zero size that is parallel to or located on the second side of the circuit carrier (2); and an orthogonal projection of the second component (4) intersects the perimeter of this virtual surface, but does not touch the spacers (5). [13] Method (20) according to claim 12, wherein the enclosing (26) is carried out while leaving the at least one contact surface exposed using a film-assisted molding process (25, 26) in which, during the molding process (25, 26), each contact surface is covered by means of a film under pressure (25) to avoid being covered with a molding compound used for molding. [14] Use of an electrical assembly (1) according to any one of claims 1 to 11 as an assembly (1) in a device or system which is designed as an industrial plant, vehicle, medical device, aircraft or as a component of any of the aforementioned devices or systems.

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