Electrical functional unit and method for manufacturing a three-dimensional electrical functional unit

Abstract

Functional unit, comprising: - a spatial body (1) with a non-conductive base material comprising a trough, the trough being filled with a non-conductive material (15); - at least two semiconductor chips (20, 21) arranged in the body's basin (1), each comprising an integrated circuit and enclosed by the non-conductive material (15) and having contact points on their surface; - at least two conductor tracks (12, 13) arranged in the body's basin (1), which are connected to the contact points of the at least two semiconductor chips (20, 21), wherein at least one conductor track (12) connects contact points of the at least two semiconductor chips (20, 21) to each other; - further conductor tracks (34) which are arranged in the well of the body (1) and have vias (32, 33) through which the further conductor tracks (34) are connected to the conductor tracks (12, 13); - further semiconductor chips (24, 25) which are placed on corresponding contact surfaces of the further conductor tracks (34) and are connected to the further conductor tracks (34); - wherein the non-conductive material (15) surrounds the other semiconductor chips (24, 25).

Description

[0001] The invention relates to an electrical functional unit and a method for producing a three-dimensional electrical functional unit.

[0002] Electrical functional units are devices that perform specific electrical functions within a facility. Such electrical functional units, for example in motor vehicles, can be control units housed in a housing to protect them from external influences. These control units perform different functions and have various applications. One example of an electrical functional unit is a sensor that is designed to detect the fill level of a tank in a protected manner. Another example of an electrical functional unit is the control unit, which can be located near the engine block.

[0003] For example, electrical functional units are manufactured as integrated circuits in a single component. However, this limits the flexibility of the functional units to the respective functions of the integrated circuit. If different or additional functions are required, it is necessary to either design and manufacture a separate integrated circuit or combine standardized assemblies. In the latter case, circuit boards are often used, with the individual chips for the different functions attached to one side.

[0004] The document DE 10 2005 013 325 A1 describes a method for connecting a plurality of integrated circuits to form a circuit module. According to the method, a module carrier is provided with a chip mounting area and a connection area. The chip mounting area has a clamping device for clamping a plurality of semiconductor chips and a connection device for electrically connecting the semiconductor chips.

[0005] US 2002 0 089 832 A1 describes a semiconductor structure with a fire-resistant protective layer. The structure comprises a chip and a passive circuit arranged on a substrate and covered by the fire-resistant layer. The protective layer holds the substrate, including the chip and circuit, in position and prevents deformation of the substrate.

[0006] Document DE 199 00 992 C2 describes a semiconductor device comprising two impurity ion implantation layers of a predetermined conductivity type in a semiconductor substrate. An oxide film and silicon layers are located on the two layers. Two transistors are located on each of the impurity ion implantation layers. Trenches are provided between the two transistors, each extending into the respective impurity ion implantation layers. Single-crystal silicon layers are connected to the respective transistors and the respective impurity ion implantation layers.

[0007] The document EP 0 056 949 A1 describes a broadband switching network with integrated switching modules for several switching points and a multilayer printed circuit board with signal lines arranged in rows and columns in different levels.

[0008] The publication DE 101 29 788 B4 describes a plastic frame for easy installation of an electronic power control unit. The frame features recesses for the precise positioning of busbars and metal plates, as well as electrical / electronic components. The frame also features a potting compound cast onto the components.

[0009] Document DE 196 28 504 A1 describes a label device and its manufacturing method. The device comprises an integrated circuit with electrode plates and an electrically insulating film covering the electrode plates.

[0010] The document US 5 179 601 A describes a method for producing a circuit structure with electrical and / or optical transmission media that are cast in a plastic.

[0011] Nevertheless, there is still a need to provide highly integrated electrical functional units that are robust against external influences and enable high flexibility with regard to various application areas.

[0012] This problem is solved by the subject matter of the independent patent claims. Further developments and refinements of the invention are the subject matter of the dependent claims.

[0013] The invention is characterized by a functional unit, particularly suitable for installation in a vehicle, which comprises a spatial body with a non-conductive base material. The body comprises a well filled with a non-conductive material. At least two semiconductor bodies or semiconductor chips, each comprising an integrated circuit, are arranged in the well of the body and enclosed by a non-conductive material. The two semiconductor bodies have contact points on their surface. Furthermore, at least two conductor tracks are provided which are arranged in the well of the body and are connected to the contact points. At least one conductor track connects the contact points of the at least two semiconductor bodies to one another.

[0014] The functional unit further comprises further conductor tracks which are arranged in the trough of the body and have vias via which the further conductor tracks are connected to the (previously mentioned) conductor tracks.

[0015] The functional unit further comprises additional semiconductor chips, which are applied to corresponding contact surfaces of the additional conductor tracks and are connected to the additional conductor tracks. The non-conductive material encloses the additional semiconductor chips.

[0016] This creates an electrical functional unit in a three-dimensional structure by assembling multilayer components inside a three-dimensional body. The components can be connected via additional conductor tracks running in different spatial directions.

[0017] The electrical functional unit based on the proposed principle has the advantage that standardized integrated circuits or chips can be combined into a highly integrated functional unit with a multilayer structure. This provides flexibility with regard to the desired application, while simultaneously making the functional unit suitable for installation in a vehicle or other means of transport. Furthermore, the existing three-dimensional body, which protects the internal structure, especially the semiconductor bodies and the conductor tracks, makes it particularly robust against mechanical stress.

[0018] In a further development, the invention is characterized by the fact that a chemically inert plastic can be used as the base material for the three-dimensional body. This makes the functional unit suitable for use in special environments, such as an oil pan, a tank, or similar.

[0019] In a further development, the invention is characterized in that the smallest dimension of the body in one spatial direction and the largest dimension of the body in another spatial direction have a ratio of > 1:20 and, in particular, a ratio of > 1:10. Thus, the body is essentially rectangular or square in shape, which, with a suitable arrangement of the semiconductor bodies within the spatial body, creates a highly integrated functional unit. The rectangular structure also increases stability compared to the more flat circuit board shapes.

[0020] In another embodiment, the invention is characterized by additional contact points arranged on an outer surface of the body and contacting the integrated circuits of the at least two semiconductor bodies via leads in the body. In this way, the integrated circuits of the semiconductor bodies can be controlled and supplied with power via external leads and corresponding contact pads on the surface of the body.

[0021] Alternatively, a further development provides for one of the conductor tracks to be configured as a conductor loop for receiving or transmitting a transponder signal. This allows the implementation of a functional unit without external contacts. Power supply and signal transmission are wireless, for example, via a transponder.

[0022] Such a functional unit is particularly useful in areas where a wired power supply is not possible or should be avoided. One example is the use of such a functional unit in a gasoline or oil tank, where the functional unit is supplied with the power required for operation via the conductor loop and a corresponding transponder signal.

[0023] In another embodiment, the functional unit is characterized by the fact that the semiconductor bodies are arranged along different propagation directions of the body. Likewise, the conductor tracks can run in sections along different propagation directions of the body. This makes it possible to realize three-dimensional structures of the semiconductor bodies within the body, as well as the conductor tracks connecting the semiconductor bodies. Overall, the integration density of the functional unit can be further increased.

[0024] If a large amount of heat is generated during operation, one embodiment of the invention is characterized by additional heat dissipation means that transport heat generated by the integrated circuit to the outside during operation. The conductor tracks can serve as heat dissipation means for this purpose.

[0025] Depending on the desired application area, suitable materials with the appropriate properties, such as color, thermal conductivity, expansion coefficient or thermal resistance, can be selected.

[0026] The method for producing a three-dimensional functional unit is characterized in that a spatial body with a well is provided. Metallization is applied along an inner wall of the well to form at least two conductor tracks. Furthermore, at least two semiconductor bodies or semiconductor chips, each with an integrated circuit formed therein, are arranged in the well and electrically coupled to the at least one conductor track via a contact arranged on the semiconductor body. Finally, the well is filled with a non-conductive material to form the spatial body. The semiconductor chips are encapsulated in the non-conductive material, wherein the well is partially and therefore not completely filled with the non-conductive material.

[0027] Several holes are drilled into the previously filled non-conductive material and the holes are filled with a conductive material to form vias for electrical contact with the conductor tracks.

[0028] Additional conductor tracks are applied to the surface of the previously filled non-conductive material. These additional conductor tracks are connected to the vias.

[0029] Additional semiconductor chips are applied to the corresponding contact surfaces of the additional conductor tracks. The contact pads of these additional semiconductor chips are connected to the corresponding contact surfaces of the additional conductor tracks.

[0030] The tub is filled with the non-conductive material, whereby the other semiconductor chips are enclosed by the non-conductive material.

[0031] The process allows for the production of a fully integrated, three-dimensional, and robust electrical functional unit that is resistant to external influences. In particular, standardized integrated circuits can be incorporated into the functional unit without the need to manufacture new designs and integrated circuits.

[0032] In a further development, the method is characterized in that, after the semiconductor body has been arranged in the well, the well is partially filled with the non-conductive material so that the material at least partially surrounds the semiconductor body. In this way, the well is populated with various semiconductor bodies in individual work steps and these are fixed via the non-conductive material. In addition, corresponding metallization levels can be structured in sections as conductor tracks on the non-conductive material in order to contact the integrated circuits of the applied semiconductor bodies.

[0033] It is possible to create openings in the non-conductive material to expose underlying conductor tracks. The openings are then filled with a conductive material for electrical contact. This allows conductor tracks to be created in multiple layers and levels within the tub, resulting in a three-dimensional conductor track structure.

[0034] In a further development, the method is characterized by pressing the conductor tracks into at least one inner wall of the tub. Alternatively, the inner wall is partially hollowed out, and the metallization is then introduced into the recess. This allows conductor tracks to be laid along the inner walls of the tub. In this context, it is possible to arrange semiconductor bodies in the tub with respect to their main surface along different spatial directions within the tub. For example, semiconductor bodies on the various side walls can be connected to the conductor tracks introduced into the side walls in this way.

[0035] The invention is explained in detail below using exemplary embodiments with the aid of drawings. They show: Fig. 1A to Fig. 1I schematic cross-sectional views of a tub illustrating an embodiment of the manufacturing process according to the proposed principle, Fig. 2A, Fig. 2B schematic cross-sectional views illustrating another embodiment of the method, Fig. 3 a perspective view of a body with conductor tracks and semiconductor bodies incorporated therein.

[0036] The elements shown below are not drawn to scale. Rather, individual components or elements have been shown enlarged or reduced in size for the sake of clarity. Components with the same effect or function have the same reference symbols. The term spatial body refers to a three-dimensional compact structure in which each of the side walls has significant dimensions in three spatial directions relative to the dimensions of the other side walls. While a circuit board has a thickness that is significantly smaller than its length or width, the dimensions in all three spatial directions of a spatial body are of the same order of magnitude. For example, the dimensions in all three spatial directions differ from one another by a factor of 20 or less, for example 10, 5 or 2. Such a spatial body is a cuboid or a cube.

[0037] Fig. 1A shows a cross-section of a base body 1, for example a tub, with side walls 10a and 10b and a base 10c. In the present exemplary embodiment, the side walls are arranged essentially perpendicular to the base 10c. The length of the base 10c is essentially a factor of 3 greater than the corresponding height of the side walls 10b. In this regard, however, other dimensions are also possible, so that overall a three-dimensional body 1 is formed. Thus, the body 1 is not primarily flat, but rather three-dimensional. The length of its smallest dimension in relation to the length of its largest dimension should not have values ​​less than 1:20 or 1:10. In the present exemplary embodiment, the ratio of the length of the side walls 10a to the base 10c is approximately 1:3.

[0038] In the first step of the procedure according to Fig. 1A, for example, the base body 1 is molded. Depending on the intended use, various types of plastics, but also ceramics or other non-conductive materials can be used.

[0039] In the next procedural steps according to Fig. 1B, metallization is introduced into the tub so that different conductor levels 12 and 13 are formed. One possibility for this is so-called laser activation, in which a partial area 14 of the bottom wall 10c and a partial area 14 of the side wall 10b are removed. In other words, the bottom 10c and the side wall 10b are structured in the area of ​​the later metallization. This can be done, for example, using laser irradiation, with the help of which a corresponding recess 14 is burned into the side wall or bottom wall of the tub. Subsequently, metallization is inserted into the recess so that the conductor track 13 is formed. In the present exemplary embodiment, the metallization is slightly thicker than the existing recess 14, so that it protrudes slightly beyond the inner surface of the tub.

[0040] An alternative way to create corresponding conductor tracks in the inner wall of the tub is to press the corresponding conductor tracks 12a and 12b into the inner wall of the tub. This slightly heats the tub at that location, so that subsequent pressing of the conductor tracks 12a and 12b creates a connection and prevents the conductor track from detaching. Heating can be achieved with a thermoplastic material, for example, using light or laser radiation. Furthermore, the conductor track can also be bonded to the inner wall of the tub using an adhesive.

[0041] According to Fig. 1C, various semiconductor bodies 20 to 23 are now connected to the conductor tracks processed in the previous steps. For this purpose, the gap between the conductor tracks 12 and 13 is filled with a plastic, and the semiconductor bodies 20 and 21 are placed on this. Both semiconductor bodies contain integrated circuits and contact pads on the underside that contact the corresponding conductor tracks 12 and 13, respectively. In the same way, further semiconductor bodies 22 and 23 are arranged on the side walls 10b and 10a, respectively, and connected to the conductor tracks located on the side walls. Thus, the conductor track 12' contacts the contact pads of the semiconductor chips 21 and 22, and the conductor track 13' contacts the contact pads of the chips 20 and 23.

[0042] In this step, the first layers of different semiconductor bodies and integrated circuits within the well are connected to each other by the corresponding arrangement along the side walls in order to achieve different functionality.

[0043] According to Fig. 1D, the existing gaps are now filled with a non-conductive material. In other words, the components, semiconductor chips 20 to 23, are potted in the next process step. This occurs partially and therefore not completely, in order to define the next process level. Various plastics can be used as potting materials.

[0044] Subsequently, according to Fig. 1E, several holes 30 and 31 for through-hole connections are drilled into the previously filled potting material 15. This can be achieved, for example, mechanically, but also via a laser or through an etching process. Holes 30, 31 expose a portion of the conductive layer 12 and 13, respectively.

[0045] A conductive material is then filled into the existing hole to contact the underlying conductor tracks 12 and 13 of the first level. Further conductor levels 14, 16, and 34 are now defined on the surface of the encapsulating material 15 and, if necessary, connected to the vias 32, 33. Further chips 24 and 25 are then applied to the corresponding contact surfaces of these conductor track levels 14, 16, and 34, and their contact pads are connected to the contacts of conductor tracks 14, 16, and 34.

[0046] In a further process step according to Fig. 1G, the existing gaps and the remaining tub are filled with a casting material up to the surface of the side walls 10a and 10b.

[0047] According to Fig. 1H, the tub is then sealed with a cover layer 60 made of the same material as the side walls 10a and 10b and the bottom wall 10c, forming the three-dimensional body. Holes 50, 51, and 52 are then drilled into the top surface 60 through the cover layer 60 and the potting material 15 to the second conductor level with the conductor tracks 14, 16, and 34. This can be done by drilling, etching, or using a laser for thermal destruction.

[0048] According to Fig. 1I the holes are then filled with a material 54, 55 and 58 and contact pads 56, 57 and 59 are provided on the surface 61 of the cover layer 60 for contacting the individual leads and chips 20, 21, 24 and 25.

[0049] This creates an electrical functional unit that is mechanically particularly robust due to its compact spatial dimensions and at the same time allows a connection to the integrated circuits located within the tub via the existing contact pads on the surface.

[0050] An alternative design of an electrical functional unit, including the manufacturing method, is described in the Fig. 2A and Fig. 2B. In the illustrated electrical functional unit, the power supply as well as the signal reception or transmission are wireless. For this purpose, the chip 24a is designed as a transponder chip and is connected to the line levels 34 and 14 within the tray. The transponder chip 24a and the second chip 25 are again enclosed by the potting material 15, which does not extend to the top of the side walls 10a and 10b of the tray. A hole 71 is drilled into the potting material 15, which exposes the transponder contact pad of the transponder chip 24a. Subsequently, according to Fig. 2B, a material 71 is filled into the existing opening in order to contact the contact pad of the transponder chip 24a.

[0051] Furthermore, a conductor loop 70 is patterned on the encapsulating material 15 just below the surface. During operation of the device, this conductor loop serves both to transmit the power required for operation and to receive and transmit the necessary transponder signals. The well is then filled with the encapsulating material 15 up to the edge of the side walls and then applied to the cover layer 60. The cover layer 60 thus hermetically seals the interior of the well, creating a hollow body containing the chips and the conductor tracks.

[0052] Due to its wireless power supply and wireless signal transmission, the electrical functional unit based on the proposed principle can be used particularly in areas of a motor vehicle where a wired power supply appears impossible or impractical. For example, the functional unit based on the proposed principle can be used as a level sensor in an oil or gasoline tank. Air pressure sensors in the tire area are also possible, as the resulting functional unit is particularly stable against mechanical stress.

[0053] Fig.Figure 3 shows a perspective view of an electrical functional unit 3. The electronic functional unit 3 comprises a substantially cuboid-shaped body 300 in the form of a box with side walls arranged substantially perpendicular to each other. The interior of the body 300 is provided with a transparent encapsulation material to identify the elements located therein.

[0054] Individual chips 330, 350, and 340 are arranged at different levels within the body 300. Specifically, a first chip 330 is arranged on the bottom of the body 300, a second chip 350 is arranged on a base 370 made of non-transparent plastic, and another chip 340 is arranged along a side wall of the body 300. Thus, the chip 340 is positioned with its main surface perpendicular to the main surfaces of the chips 350 and 330, respectively, and parallel to a side wall of the body 300.

[0055] Various openings 301 to 304, 305, and 306 are provided in the side walls of the body 300. These openings lead to contact pads (not shown) on the outside of the walls of the body 300 and are connected within the body 300 via conductive paths 311 to 316 to corresponding contact pads on the top side of the semiconductor chips 330 and 350, respectively.

[0056] Specifically, the openings 302 and 303, as well as 305 and 306, are routed via conductive planes 312, 313, 315, and 316 to contact pads 322 on the top side of the chip 330. The conductive path 314 contacts the hole 304 in the sidewall of the body 300 and runs along the sidewalls and bottom of the body 300 to a contact pad on the underside of the chip 330. Accordingly, the conductive paths 312, 313, 315, and 316 are arranged in one plane, and the conductive path 314 is arranged in a second plane.

[0057] The conductor track 311 contacts the hole 301 in the side wall of the body 300 and leads to a contact pad on the underside of the chip 350. Likewise, a contact pad 327 of the chip 330 is connected to a contact pad on the underside of the chip 350 via a conductor track 317 running parallel to the bottom of the well. The conductor tracks for contacting the chip 350 and the socket 370 are good thermal conductors, so they conduct heat generated during operation of the integrated circuit of the chip 350 to the outside.

[0058] Chip 340 is arranged vertically relative to the two semiconductor chips 350 and 330. On its front side, it has a plurality of connection contacts 341 and 342, which are connected to the contacts on the underside of chip 350 via conductor tracks in one plane.

[0059] The functional unit thus comprises a plurality of semiconductor chips connected to one another via conductor tracks at different levels within a body 300. The transparent plastic material used makes lithography particularly easy to perform by means of an exposure process on the three-dimensional body. This is achieved by exposing the individual layers from the outside, thereby structuring them. Thermoplastics, as well as epoxy resins and other mechanically stable and / or chemically inert materials, can be used as plastics for the body 300 and as encapsulation material.

[0060] The functional unit also has the advantage that the proposed design allows the use of semiconductor chips that can have contacts on different sides. This allows for the spatial integration of a wide variety of functional assemblies and integrated circuits in different spatial directions.

Claims

[1] Functional unit comprising: - a spatial body (1) with a non-conductive base material, which comprises a trough, the trough being filled with a non-conductive material (15); - at least two semiconductor chips (20, 21) arranged in the well of the body (1), each comprising an integrated circuit and enclosed by the non-conductive material (15) and having contact points on their surface; - at least two conductor tracks (12, 13) arranged in the trough of the body (1) and connected to the contact points of the at least two semiconductor chips (20, 21), wherein at least one conductor track (12) connects contact points of the at least two semiconductor chips (20, 21) to one another; - further conductor tracks (34) which are arranged in the trough of the body (1) and have through-contacts (32, 33) via which the further conductor tracks (34) are connected to the conductor tracks (12, 13); - further semiconductor chips (24, 25) which are applied to corresponding contact surfaces of the further conductor tracks (34) and are connected to the further conductor tracks (34); - wherein the non-conductive material (15) encloses the further semiconductor chips (24, 25). [2] Functional unit according to claim 1, wherein at least two contact points (56, 57, 59) are arranged on an outer surface (61) of the body (1), which contact the integrated circuits of the at least two semiconductor chips (20, 21) via leads (54, 55, 58) in the body (1). [3] Functional unit according to one of claims 1 to 2, wherein the body (1) comprises at least one heat dissipation means (370) which transports heat generated by the integrated circuit during operation of the integrated circuit to the outside. [4] Functional unit according to one of claims 1 to 3, wherein the base material of the body (1) and the non-conductive material (15) surrounding the semiconductor chips (20, 21, 24, 25) are formed from the same material. [5] A method for producing a three-dimensional functional unit, comprising: - Providing a spatial body (1) with a trough formed with a non-conductive base material; - applying a metallization to form at least two conductor tracks (12, 13) along an inner wall of the tub; - arranging at least two semiconductor chips (20, 21), each having an integrated circuit formed therein, in the well and electrically coupling the integrated circuits of the semiconductor chips (20, 21) to the conductor tracks (12, 13) via contact points arranged on surfaces of the respective semiconductor chips (20, 21); - filling the well with a non-conductive material (15), wherein the semiconductor chips (20, 21) are encapsulated by the non-conductive material (15), and wherein the well is partially and therefore not completely filled by the non-conductive material (15); - making a plurality of holes (30, 31) in the previously filled non-conductive material (15) and filling the holes (30, 31) with a conductive material to form through-holes (32, 33) for electrically contacting the conductor tracks (12, 13); - applying further conductor tracks (34) to the surface of the previously filled non-conductive material (15) and connecting the further conductor tracks (34) to the vias (32, 33); - applying further semiconductor chips (24, 25) to corresponding contact surfaces of the further conductor tracks (34) and connecting their contact pads to the corresponding contact surfaces of the further conductor tracks (34); - filling the trough with the non-conductive material (15), wherein the further semiconductor chips (24, 25) are enclosed by the non-conductive material (15).

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