DE102022201855A1 - LGA assembly and circuit arrangement with an LGA assembly - Google Patents

Abstract

The invention relates to an LGA assembly (10; 10a), with a base element (20; 20a) designed as a flat component that serves to contact a circuit carrier (12), in particular in the form of an interposer element (22; 22a), with a preferably rectangular Base area, at least one press-in pin (28) being arranged on at least two oppositely arranged edge regions of the base element (20; 20a).

Description

technical field

The invention relates to an LGA (Land Grid Array) assembly that enables a particularly secure and mechanically advantageous connection to a circuit carrier. Furthermore, the invention relates to a circuit arrangement with an LGA assembly according to the invention.

State of the art

LGA assemblies are known from the prior art in a variety of ways ( DE 11 2005 003 671 T1 , EP 3 792 672 A1 ). An LGA assembly is connected to a circuit carrier, for example, by arranging the LGA assembly with its contact pads overlapping the contact areas of the circuit carrier and pressing the contact pads of the LGA assembly against the surface of the circuit carrier by means of a mechanical component, e.g. a clamping frame Circuit carrier are subjected to a force to establish the electrical contact. It is essential for such an electrical connection of the LGA assembly to the circuit carrier that a sufficiently high contact force can always be generated in the connection area, even under possibly changing conditions or with increased stress on the connection, for example as a result of temperature changes or vibrations. In addition, the mentioned connecting element in the form of the clamping frame is used only for the mechanical transmission of forces, but it does not itself have any electrical functionality.

Alternatively, it is also known to connect the LGA assembly to the circuit carrier by means of soldered connections. However, the reliability of the individual soldered connections must be regarded as critical in view of the large number of soldered connections, especially with large LGA assemblies and temperature changes.

Disclosure of Invention

The LGA assembly according to the invention with the features of claim 1 has the advantage that it enables a particularly reliable and secure connection of the LGA assembly to the circuit carrier, even with temperature changes and/or high mechanical stresses, e.g. as a result of vibrations.

The invention is based on the idea of equipping the LGA assembly with press-in pins which can be pressed into press-in openings in the circuit carrier. Such a solution enables, on the one hand, the transmission of relatively high contact pressures of the LGA assembly in the direction of the circuit carrier and, on the other hand, absorption of thermal stresses in the LGA assembly in the event of temperature changes. Furthermore, the LGA assembly according to the invention has the advantage that the structural size of a circuit arrangement with an LGA assembly according to the invention is reduced in comparison with a solution which has a clamping frame, with high reliability.

Against the background of the above explanations, it is therefore provided in an LGA assembly according to the invention with the features of claim 1 that it has a base element which serves to contact a circuit carrier and is designed as a flat component, in particular in the form of an interposer element, with a preferably rectangular base area At least one press-in pin is arranged on at least two oppositely arranged edge regions of the base element, which press-in pin preferably protrudes perpendicularly from the plane of the base element, and which is designed to form a press-fit connection with a press-in opening of the circuit carrier.

Advantageous developments of the LGA assembly according to the invention are specified in the dependent claims.

It is very particularly preferred if the at least two press-in pins are arranged in corner regions of the base element. In particular, it is provided that at least four press-in pins are provided, which are arranged in the respective corner regions in the case of a rectangular base area of the base element. This enables a homogeneous application of force or application of force in the direction of the circuit carrier and reduces deformation or deformation of the LGA assembly under mechanical stress.

A further aspect of the invention relates to the possibility that at least one press-in pin also has an electrical functionality in addition to its functionality for forming a mechanical connection between the LGA assembly and the circuit carrier. In particular, it is therefore provided that the press-in pin is designed to form a signal transmission or a power supply between a component connected at least indirectly to the base element and the circuit carrier. In the case of powering the LGA assembly through the press-in pin, it is worth mentioning that it is possible due to the relatively large contact area between the press-in pin and the LGA assembly and between the press-in pin and the circuit carrier, compared to a solution in which the Power is supplied via the LGA pads to transmit significantly higher currents or electrical power.

In a preferred development of such a configuration, it is provided that the press-in pin is coupled to the component by means of a connecting element, in particular by means of a bonding wire.

A further preferred embodiment of the invention provides that the press-in pin is designed at least indirectly to form a defined distance, in particular a soldering gap, between the base element and the circuit carrier. This serves to increase the quality of the soldered connections and to ensure reliability. In this case, the press-in pin forms, so to speak, an assembly aid when the LGA assembly is pressed in or joined to the circuit carrier. It is therefore sufficient to connect the LGA assembly to the circuit carrier until it stops, but monitoring of a press-in depth or a press-in path of the press-in pin is not necessary.

For better transmission of the press-in forces from the LGA assembly into the component or in the LGA assembly, it can also be provided that the press-in pin or the press-in pins is/are connected to a force introduction element at the end regions facing away from the circuit carrier. In particular, it is provided that the force introduction element is in the form of a (rigid) metal layer or a metal element, in particular consisting of copper.

In a preferred development of such a force introduction element, it is provided that it is designed to form a shielding element against electromagnetic radiation. This protects the LGA assembly from electromagnetic radiation and/or at least reduces or prevents electromagnetic radiation being emitted by the LGA assembly to the environment.

In a preferred embodiment of such a metal force introduction element in an LGA assembly, it is provided that the force introduction element is coupled to a component to be cooled, optionally with an electrically non-conductive layer interposed. This reduces the thermal load on the LGA assembly.

In order to protect the LGA assembly from external influences, in particular from moisture, it can be provided that the LGA assembly is surrounded by a housing made of plastic or a protective compound, in particular a molding compound. The molding compound can contain components, in particular ceramics, which serve to increase the strength and/or improve the thermal conductivity. Solutions are also included in which the protective mass consists of a ceramic composite material or consists entirely of ceramic.

Although the LGA assembly, in particular when several or a large number of press-in pins are used, already enables an electrical connection between the LGA assembly and the circuit carrier through the contact pressure between the electrically conductive areas, it is particularly preferably provided that the base element with is soldered to the circuit carrier in the contact areas outside of the press-in pins.

Furthermore, the invention also includes a circuit arrangement with an LGA assembly configured according to the invention and a circuit carrier, the circuit carrier having press-in openings for interacting with press-in sections of the press-in pins of the LGA assembly.

Further advantages, features and details of the invention result from the following description of preferred embodiments of the invention and from the drawings.

character list

• 1 and 2 each show a simplified longitudinal section of different LGA assemblies with press-in pins that are connected to circuit carriers.

Embodiments of the invention

Identical elements or elements with the same function are provided with the same reference numbers in the figures.

In the 1 a circuit arrangement 100 is shown, which consists of an LGA assembly 10 and a circuit carrier 12 connected to the LGA assembly 10 . In the exemplary embodiment, the circuit carrier 12 is embodied as a multilayer printed circuit board 14 and has electrically conductive sections 16 on the side facing the LGA assembly 10, which are electrically contacted in a known manner with electrically conductive contact pads 17 formed on the LGA assembly 10 , Preferably by (not shown in detail) soldered connections. The contact pads 17 are in a matrix structure at defined intervals (also perpendicular to the plane of the drawing 1 running), as known from the prior art, arranged. Furthermore, the contact pads 17 of the LGA assembly 10 are formed on a plate-like or flat base element 20 in the form of an interposer element 22 . The interposer element 22 is in turn coupled, for example, to an IC component 24 on the side facing away from the circuit carrier 12 .

The connection between the LGA assembly 10 and the circuit carrier 12 is made in addition to the mentioned soldered connections between the sections 16 and the contact pads 17, for example, by means of four arranged in edge or corner regions 26 of the base element 20 and protruding perpendicularly from the plane of the base element 20 Press-in pins 28. Due to the representation of the 1 are in the 1 Only two press-in pins 28 can be seen, the other two (not visible) press-in pins 28 are located perpendicular to the plane of the drawing 1 .

The press-in pins 28 are connected to the interposer element 22 in that they penetrate, for example, through openings 30 in the interposer element 22 and are connected there to the base element 20 by means of a press connection. Alternatively or additionally, an integral connection can also be provided. In addition, it should be mentioned that with a corresponding dimensional tolerance of the through-openings 30 and the press-in pins 28 in connection with the material of the press-in pins 28, it is also possible to simultaneously produce a material connection during the press connection without an additional work step (a so-called "press-fit connection"). ). Furthermore, the circuit carrier 12 has press-in openings 32 which interact with press-in sections 33 of the press-in pins 28 in order to form a press-fit connection in each case.

In the exemplary embodiment shown, the press-in pins 28 also have electrical functionality. For this purpose, it is provided that, for example, one of the electrically conductive layers of the circuit carrier 12 is provided with a coating in the area of the press-in opening 32 in order to form an electrically conductive connection with the press-in pin 28 . On the side facing away from the circuit carrier 12, for example, the two in the 1 Recognizable press-in pins 28 each have a bonding wire 34 on their front side, which is electrically conductively connected to the IC component 24 .

The electrically conductive connection between the circuit carrier 12 and the LGA assembly 10 can be used either to enable signal transmission between the circuit carrier 12 and the LGA assembly 10 or the IC component 24, or it is used to carry current or Voltage supply of the LGA assembly 10 or the IC component 24.

Furthermore, the press-in pins 28 and/or the circuit carrier 12 have stop means which are used to form a defined soldering gap between the contact pads 17 and the electrically conductive sections 16 of the interposer element 22 of the LGA assembly 10 . For this purpose, it can either be provided that the press-in pin 28 has a larger diameter than the press-in openings 32 in a partial area that is located outside of the press-in openings 32, or that the press-in openings 32 in the circuit carrier 12 are designed as blind holes, as shown, in order to to limit the press-in depth of the press-in pins 28 in the circuit carrier 12.

Finally, it is shown that the interposer element 22 is surrounded by a molding compound 40 serving as a protective compound on the side facing away from the circuit carrier 12 for protection against external influences. The protective or molding compound 40 can be equipped with additives or particles, for example made of ceramic, for example to improve the heat dissipation and/or to increase the strength. Ceramic composites or solutions consisting entirely of ceramic are also possible as protection.

In the 2 1 shows a circuit arrangement 100a, the LGA assembly 10a of which comprises a (rigid) housing 45 formed, for example, from two components 42, 44. An (inner) sensor element 48 is arranged in a cavity 46 within the housing 45 and is connected to a component 24a via copper connections 50 . The press-in pins 28 , which are also arranged in the corner regions 26 , are covered on the end face facing away from the circuit carrier 12 by a force distribution element 52 , which is soldered to the press-in pins 28 , for example.

The force distribution element 52 is designed, for example, in the form of a (thin) plate made of copper or the like and can enable a homogeneous introduction of force into the interposer element 22a and the housing 46 when the press-in pins 28 are pressed in.

Furthermore, it is possible through a suitable geometry in connection with an electrically conductive material for the force introduction element 52 that this acts simultaneously as a shielding element against electromagnetic radiation that is generated either by the LGA assembly 10a or from the environment in the direction of the LGA Building group 10a works. In addition, the force distribution element 52 can also serve to dissipate heat from the sensor element 48 . For this purpose, the force introduction element 52 is connected to the sensor element 48 in a thermally conductive manner, for example by means of a thermally conductive adhesive or the like (not shown).

In order to prevent the sensor element 48 from coming into electrically conductive contact with the force distribution element 52 when implementing an electrical functionality of the press-in pins 28 in accordance with the circuit arrangement 100, provision can be made for a passivation layer 54 or the like to be provided between the sensor element 48 and the force distribution element 52. Ä. Non-conductive coupling layer is arranged.

The LGA assemblies 10, 10a and circuit configurations 100, 100a described so far can be altered or modified in many ways without deviating from the idea of the invention. So it is of course also conceivable, the circuit arrangement 100 according to 1 equipped with a force introduction element 52 corresponding to the circuit arrangement 100a.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 112005003671 T1 [0002]
• EP 3792672 A1 [0002]

Claims (14)

LGA assembly (10; 10a), with a base element (20; 20a) which serves to contact a circuit carrier (12) and is designed as a flat component, in particular in the form of an interposer element (22; 22a), with a preferably rectangular base area, wherein on At least two oppositely arranged edge regions of the base element (20; 20a) each have at least one press-in pin (28) which preferably protrudes perpendicularly from the plane of the base element (20; 20a) and which is designed to have a press-in opening (32) in the Circuit carrier (12) to form a press connection. assembly claim 1 , characterized in that the at least two press-in pins (28) are arranged in corner regions (26) of the base element (20; 20a). assembly claim 1 or 2 , characterized in that the press-in pin (28) is designed to form a signal transmission or a power supply between a base element (20; 20a) at least indirectly connected component (24; 24a) and the circuit carrier (12). assembly claim 3 , characterized in that the press-in pin (28) is coupled to the component (24; 24a) by means of a connecting element, in particular by means of a bonding wire (34). Assembly according to one of Claims 1 until 4 , characterized in that stop element that the press-in pin (28) is at least indirectly designed to form a defined soldering gap between the base element (20; 20a) and the circuit carrier (12). Assembly according to one of Claims 1 until 5 , characterized in that the press-in pins (28) are connected to a force introduction element (52) on the end regions facing away from the circuit carrier (12). assembly claim 6 , characterized in that the force introduction element (52) is in the form of a metal layer, in particular a copper layer. assembly claim 6 or 7 , characterized in that the force introduction element (52) is designed to form a shielding element against electromagnetic radiation. assembly claim 7 or 8th , characterized in that the metal layer is coupled to an element to be cooled, in particular a sensor element (48), optionally with the interposition of an electrically non-conductive layer (54). Assembly according to one of claims 3 until 9 , characterized in that the component (24a) on the side facing away from the base element (20a) is contacted with a further component, in particular a sensor element (48). Assembly according to one of Claims 1 until 10 , characterized in that the LGA assembly (10; 10a) of a plastic housing (45) or a protective or molding compound (40) is at least partially surrounded. assembly claim 11 , characterized in that the protective or molding compound (40) to increase the strength and / or to improve the thermal conductivity serving components, in particular ceramics, or consists of a ceramic composite or consists entirely of ceramics. Assembly according to one of Claims 1 until 12 , characterized in that the base element (20; 20a) is soldered to the circuit carrier (12) between electrically conductive sections (16) and contact pads (17). Circuit arrangement (100; 100a), with an LGA assembly (10; 10a), according to one of Claims 1 until 13 is formed, and with a circuit carrier (12) which has press-in openings (32) for cooperation with press-in sections (33) of the press-in pins (28).

Images