Multi-package with two substrates and process and automation technology field device for determining and / or monitoring at least one process parameter

Abstract

The invention relates to a multi-package (1) with two substrates (2), wherein each substrate (2) has a first surface (3) and a second surface (4), wherein on each first surface (3) at least one electronic circuit (5) is arranged, wherein on each second surface (4) at least one contact face (6) for connection to a component (7) is arranged, wherein the two substrates (2) are arranged opposite one another such that the two first surfaces (3) face one another, and wherein the two substrates (2) are electrically and mechanically connected to one another. The invention also relates to a field device (17) with a multi-package (1).

Description

[0001] Multi-package with two substrates and field device of process and automation technology for determining and / or monitoring at least one process parameter

[0002] The invention relates to a multi-package with two substrates and a field device in process and automation technology for determining and / or monitoring at least one process parameter.

[0003] Field devices are used to determine and / or monitor process variables. Field devices essentially refer to all devices that are used close to the process and provide or process-relevant information. These include, for example, level measuring devices, flow measuring devices, pressure and temperature measuring devices, pH / redox potential measuring devices, conductivity measuring devices, etc., which measure the corresponding process variables: level, flow, pressure, temperature, pH value, or conductivity.

[0004] Field devices often have a sensor unit, in particular at least temporarily and / or at least partially in contact with a process medium, which serves to generate a signal dependent on the process variable. Furthermore, they often have an electronics unit arranged in a housing, wherein the electronics unit serves to process and / or transmit signals generated by the sensor unit, in particular electrical and / or electronic signals. The electronics unit can, in particular, comprise packages, components, and circuit boards.

[0005] A package is a casing or housing for an electronic circuit. A package has contact surfaces on one of its outer sides for the electrical and mechanical connection to another component, e.g. a printed circuit board. The electronic circuit is applied to a substrate which is made of a plastic or composite material or a ceramic, for example. The electronic circuit typically has one or more (electrical) components, e.g. semiconductor elements such as transistors or diodes or active and passive components such as relays, resistors and capacitors. The electronic circuit can also be designed as an integrated circuit, in particular as an application-specific integrated circuit (ASIC), and can already be arranged on the substrate with its own housing.Previous packages have always been designed in such a way that they can only be electrically contacted from one side.

[0006] The task therefore arises to provide a package with improved contact options.

[0007] According to the invention, the object is achieved by a multi-package according to claim 1 and a field device according to claim 10.

[0008] With regard to the multi-package, the object is achieved according to the invention by a multi-package with two substrates, wherein each substrate has a first surface and a second surface, wherein at least one electronic circuit is arranged on the first surface, wherein at least one contact surface for connection to a component is arranged on the second surface, wherein the two substrates are arranged opposite one another in such a way that the two first surfaces face one another, and wherein the two substrates are electrically and mechanically connected to one another.

[0009] The multi-package according to the invention combines two substrates with one another such that the multi-package can be electrically contacted on the two opposite second surfaces by means of the respective at least one contact area. The multi-package can be electrically and mechanically connected to another component both from below and from above. The two substrates form in particular a cover for the electronic circuits arranged between the substrates. Furthermore, the use of two substrates enables a higher component density within the multi-package than if two separate packages, each with one substrate, were used. The two substrates are electrically and mechanically connected to one another in particular within a space formed by the two substrates.In particular, the two substrates are arranged relative to one another in such a way that at least one electronic circuit is arranged between the two substrates.

[0010] In one embodiment, each of the two substrates is a ceramic substrate. For example, the two substrates are essentially made of aluminum oxide. A ceramic substrate is understood, in particular, to be a substrate that is made of at least 90% ceramic.

[0011] A further development provides that the two substrates are connected to one another in an edge region of at least one of the substrates. Ceramic substrates in particular can have a step, in particular a continuous step, in their edge region. The step can, for example, have connection surfaces by means of which an electrical connection to a component is enabled. The two substrates can preferably be electrically and mechanically connected to one another by means of their edge region and / or their two steps. This applies in particular if the two substrates are the same size. If the substrates are of different sizes, the step of the smaller substrate and, if appropriate, a section of the step of the larger substrate can be used to connect the two substrates.

[0012] In a further embodiment, at least one of the two substrates has at least one spacer element on its first surface. For example, the two substrates are made of a plastic that is optionally filled with other materials. Such substrates are typically designed without a step in the edge region and are flat or planar. To ensure that the electronic circuits on the two first surfaces do not touch each other, at least one spacer element is provided on one of the two first surfaces, which sets a defined distance between the two substrates. Preferably, one of the two first surfaces has a plurality of spacer elements or both first surfaces have at least one spacer element. The at least one spacer element is arranged on at least one of the two substrates in such a way that it is arranged between the two substrates.

[0013] In a further embodiment, the two substrates are connected to one another by means of a solder connection and / or a potting compound. The solder connection is preferably arranged continuously between the two substrates. In the case of two ceramic substrates, each having a step, the solder connection can be arranged in particular in the edge region of at least one of the two ceramic substrates. The potting compound is preferably arranged between the two substrates. Alternatively, the potting compound can be arranged in particular in the region of the at least one spacer element. The potting agent for producing the potting compound can be selected as a non-conductive potting agent. The solder or solder paste for producing the solder connection can be selected as an electrically conductive solder paste.

[0014] Preferably, the two substrates are electrically connected to each other within a gap formed between them. The electrical connection between the two substrates can be established, for example, by means of a solder connection or by bonding.

[0015] Preferably, the two substrates are bonded together in such a way that a gap formed between them is sealed. Sealing the gap protects the electronic circuits located therein from dust and / or moisture.

[0016] In one development, the two substrates can be electrically contacted by means of the two second surfaces. Since both second surfaces each have at least one contact area, the multi-package can advantageously be contacted by both second surfaces. Preferably, the multi-package is electrically and mechanically connected to a further component on each of the two second surfaces. In one embodiment, a further component is arranged on the first surface of at least one of the two substrates. In addition to the at least one electronic circuit on one of the two substrates, further components and / or further electronic circuits can also be arranged.

[0017] With regard to the field device, the object is achieved according to the invention by a field device of process and automation technology for determining and / or monitoring at least one process parameter, wherein the field device comprises at least one multi-package according to one of the preceding claims. Preferably, the multi-package is connected to a component on both second surfaces. The at least one multi-

[0018] Package can be arranged, for example, between two components, two circuit boards or a component and a circuit board.

[0019] In one embodiment, the field device is a pressure measuring device for determining and / or monitoring a pressure of a medium, wherein one of the two second surfaces is electrically and mechanically connected to a plug, wherein the other of the two second surfaces is electrically and mechanically connected to a pressure measuring cell.

[0020] The present invention will be explained in more detail below with reference to the following figures, Fig. 1 - 7. They show:

[0021] Fig. 1 : an embodiment of a ceramic substrate.

[0022] Fig. 2: a first embodiment of the multi-package according to the invention in longitudinal section.

[0023] Fig. 3: the first embodiment of the multi-package according to the invention in cross section.

[0024] Fig. 4: an embodiment of another substrate.

[0025] Fig. 5: A second embodiment of the multi-package according to the invention in longitudinal section. Fig. 6: The second embodiment of the multi-package according to the invention in cross section.

[0026] Fig. 7: an embodiment of a field device according to the invention.

[0027] Fig. 1 shows an example of a ceramic substrate 2. The ceramic substrate 2 has a first surface 3 with an electronic circuit 5 arranged thereon and a second surface 4 with at least one contact surface 6 arranged thereon. In the example shown, the two contact surfaces 6 are designed as a ball grid array. Land grid arrays or other embodiments of the contact surfaces 6 are of course also possible. The ceramic substrate 2 has a step 23 in its edge region 8. For example, electrical lines run through the step so that the electronic circuit 5 can be electrically connected to the step 23 by means of one or more bonds 22. In addition, the step 23 can have connection surfaces 24, which likewise serve for electrical contact.

[0028] A multi-package 1 formed from two ceramic substrates 2 is shown in longitudinal section in Fig. 2. The two substrates 2a, 2b are arranged opposite one another so that the two first surfaces 3 face each other. In particular, the two ceramic substrates 2a, 2b are electrically connected to one another within the intermediate space 12. The two ceramic substrates 2a, 2b are electrically and mechanically connected to one another. This is done, for example, by means of one or more solder connections 10. In Fig. 2, the two ceramic substrates 2a, 2b are connected by means of two solder connections 10, of which the inner solder connection 10a lies within the intermediate space 12 formed by the two substrates 2a, 2b, and the outer solder connection 10b connects the two edge regions 8 on the outside. The inner solder connection 10a and the outer solder connection 10b are also shown in Fig. 3, which shows the multi-package from Fig. 2 in cross section.The outer solder connection 10b is arranged, for example, continuously around the edge region 8. The outer solder connection 10b can thus ensure sealing of the intermediate space 12, particularly against dust and / or moisture. Due to this arrangement of the two ceramic substrates 2a, 2b, the second surface 4 is exposed from the outside of the multi-package 1. The multi-package 1 can thus be electrically contacted by both second surfaces 4. This means that each of the two second surfaces 4 can be electrically and mechanically connected to a component 7.

[0029] Another exemplary embodiment of a substrate 2 is shown by way of example in Fig. 4. In addition to an electronic circuit 5, further optional components 16 are arranged on the first surface 3. Additionally, spacer elements 9 are arranged, which serve to set a defined distance between the two substrates 2a, 2b. This exemplary embodiment is particularly suitable for substrates 2 that do not consist essentially of ceramic, but possibly only have small amounts of ceramic. The contact surfaces 6 on the second surface 4 are designed, for example, as a ball grid array.

[0030] Fig. 5 shows a multi-package comprising two substrates 2a, 2b from Fig. 4 in longitudinal section. Again, the two first surfaces 3 are arranged facing each other and the two substrates 2a, 2b are connected to each other. In this case, the two substrates 2a, 2b are connected to each other by means of an encapsulation 11. The encapsulation 11 is arranged in particular such that it encloses the at least one spacer element 9 and / or the electronic circuit 5. Preferably, the encapsulation 11 encloses all components on the two first surfaces 3 of the two substrates 2a, 2b. In Fig. 6, the multi-package 1 shown in Fig. 5 is shown in cross section. In the examples shown, one substrate in each case has at least one spacer element, but it is also possible for both substrates to have at least one spacer element.

[0031] In the selected examples, the two substrates 2a, 2b are each the same size. However, embodiments are also conceivable in which one of the two substrates is larger than the other, so that the smaller of the two substrates covers only part of the first surface of the larger substrate. Furthermore, multi-packages comprising a ceramic substrate and a substantially non-ceramic substrate are also possible.

[0032] The multi-package 1 according to the invention can be used in a field device 17, some of which were already mentioned at the beginning. For example, a multi-package 1 consisting of two ceramic substrates 2a, 2b can be used for a pressure measuring device 18. One such example is shown in Fig. 7. The multi-package 1, shown here without details for clarity, is connected on both second surfaces 4 by means of the contact surfaces 6 and solder connections 32, on the one hand to a connector 20 and on the other hand to a ceramic pressure measuring cell 29. The pressure measuring cell 29 comprises a measuring diaphragm 30 and a base body 29, which are connected by means of a joint 31. A first pressure p1 of a medium 19 acts on the measuring diaphragm 30. In addition, a pressure supply 28 can be provided, which provides a second pressure, e.g., a reference pressure, between the measuring diaphragm 30 and the counter body 29.The measuring electrode 25 and the counter electrode 26, which form an electrical transducer, are arranged in the pressure chamber formed by the measuring diaphragm 30 and the base body 29. At least the counter electrode 26 is connected to the multi-package 1 via a supply line 27, which in this example is designed as on-site electronics. The power supply, among other things, is provided via the connector 20. The other components of the pressure measuring device 18, such as the additional electronics, etc., have not been shown for the sake of clarity.

[0033] List of reference symbols

[0034] 1 multi-package

[0035] 2 Substrat

[0036] 2a first substrate

[0037] 2b second substrate

[0038] 3 first surface

[0039] 4 second surface

[0040] 5 electronic circuit

[0041] 6 Contact surface

[0042] 7 Component

[0043] 8 Marginal area

[0044] 9 Spacer element

[0045] 10 solder connection

[0046] 10a solder connection inside

[0047] 10b Solder connection outside

[0048] 11 Casting

[0049] 12 space

[0050] 16 additional components

[0051] 17 field device

[0052] 18 Pressure gauge

[0053] 19 Medium

[0054] 20 plugs

[0055] 21 Pressure measuring cell

[0056] 22 Bond connection

[0057] 23 Level

[0058] 24 connection surface

[0059] 25 measuring electrode

[0060] 26 Counter electrode

[0061] 27 Guide

[0062] 28 Pressure feed

[0063] 29 basic bodies

[0064] 30 measuring membrane

[0065] 31 joint

[0066] 32 Solder connection to another component

Claims

Patent claims 1 . Multi-package (1 ) with two substrates (2), wherein each substrate (2) has a first surface (3) and a second surface (4), wherein at least one electronic circuit (5) is arranged on the first surface (3) in each case, wherein at least one contact surface (6) for connection to a component (7) is arranged on the second surface (4), wherein the two substrates (2) are arranged opposite one another in such a way that the two first surfaces (3) face one another, and wherein the two substrates (2) are electrically and mechanically connected to one another.

2. Multi-package (1) according to claim 1, wherein the two substrates (2) are each a ceramic substrate.

3. Multi-package (1) according to one of claims 1 - 2, wherein the two substrates (2) are connected to one another in an edge region (8) of at least one of the substrates (2).

4. Multi-package (1) according to one of claims 1 -3, wherein at least one of the two substrates (2) has at least one spacer element (9) on the first surface (3).

5. Multi-package (1) according to one of claims 1 -4, wherein the two substrates (2) are connected to one another by means of a solder connection and / or a potting compound.

6. Multi-package (1) according to one of claims 1 - 5, wherein the two substrates (2) are electrically connected to one another within a space (12) formed by the two substrates (2).

7. Multi-package (1) according to one of claims 1 -6, io wherein the two substrates (2) are connected to one another in such a way that an intermediate space (12) formed by the two substrates (2) is sealed.

8. Multi-package (1) according to one of claims 1 -7, wherein the two substrates (2) can be electrically contacted by means of the two second surfaces (4).

9. Multi-package (1) according to one of claims 1 -8, wherein a further component (16) is arranged on the first surface (3) of at least one of the two substrates (2).

10. Field device (17) of process and automation technology for determining and / or monitoring at least one process parameter, wherein the field device (17) has at least one multi-package (1) according to one of the preceding claims.

11. Field device (17) according to claim 10, wherein the field device (17) is a pressure measuring device (18) for determining and / or monitoring a pressure of a medium (19), wherein one of the two second surfaces (4) is electrically and mechanically connected to a plug (20), wherein the other of the two second surfaces (4) is electrically and mechanically connected to a pressure measuring cell (21).

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