DE102017012351B4 - ELECTRICAL CONTACT ARRANGEMENT AND ELECTRICAL CONNECTOR ARRANGEMENT - Google Patents

Abstract

Electrical contact arrangement for connecting a contact carrier (102) to a mating contact carrier (104), the contact arrangement comprising: an electrically conductive contact element (106) which is connected to at least one conductor track arranged on the contact carrier (102), an electrically conductive mating contact element (108) which is arranged on a mating contact carrier (104), the contact element (106) and the at least one mating contact element (108) being aligned one above the other, an insulating layer (118, 154) which is arranged between the contact carrier (102) and the mating contact carrier (104) such that the contact element (106) protrudes through the insulating layer (118, 154), the at least one contact element (106) being elastically deformable along a direction (114) of connection to the mating contact element (108), the contact carrier (102) being made of an electrically insulating carrier material (126, 138) with a is manufactured from a structured metal layer embedded therein and wherein the contact element (106) is exposed on both surfaces so that it can be connected in an electrically conductive and mechanically fixed manner through the contact carrier (102) via an electrically conductive connecting element (110) to the associated electrically conductive mating contact element (108).

Description

The present invention relates to an electrical contact arrangement and an associated electrical connector arrangement, in particular for use in implantable components.

Electrically active implants with a large number of electrical channels can now be manufactured using micro-technical manufacturing processes, for example photolithography, laser structuring or a combination of these two processes. Such implants must be connected to a rigid component that acts as an intermediary element between the miniaturized flexible microsystem (for example a microelectrode array) and the lines that lead to the driver electronics. The rigid component can, for example, be formed by the electronics itself with or without an additional housing. In order to be able to reduce the size of the overall system, the contact elements that establish the electrical connection between the flexible and the rigid substrate are densely packed. Unfortunately, they are often in the form of a square array.

For the connection between a flexible contact carrier and a corresponding rigid counter contact carrier, so-called Microflex connections are often used, as described, for example, in the publication Meyer, J.-U., Stieglitz, T., Scholz, O., Haberer, W., Beutel, H., “High Density Interconnects and Flexible Hybrid Assemblies for Active Biomedical Implants”, IEEE Trans. on Components, Packaging and Manufacturing Technology Part B: Advanced Packaging (IEEE Trans. on Advanced Packaging), vol. 24 , no. 3, pp. 366-374 (2001). Particularly with larger, densely packed arrays of contact elements, the problem is that the contact elements are subjected to high mechanical stress and therefore failures occur due to the forces acting on them.

These contact elements must not only be electrically insulated from each other over a sufficient distance, but also by an electrically non-conductive polymer, which in known arrangements is referred to as underfill material.

Typically, low-viscosity epoxy resins are used as underfill insulators. However, these epoxy resins do not have the long-term stability required for years of use in aqueous or humid environments, such as those encountered by an active implantable assembly. In general, silicone rubber (polydimethylsiloxane, PDMS) is usually chosen as the insulator material for use in implantable components. However, PDMS has an even higher viscosity than epoxy, so the problem arises that air bubbles can become trapped between the contacts when PDMS is used as an underfill.

On the other hand, sufficiently water-stable and hydrothermally stable epoxy materials are not biocompatible, so they cannot be used for implantable components. Adhesive insulating materials, such as anisotropic conductive adhesives or epoxy-based foil tapes, also do not have the hydrothermally stable adhesive effect required for implants if they are used in a constantly moist environment.

EN 101 05 351 A1 relates to an electronic component with a semiconductor chip on which an interconnect structure is arranged, which has a rewiring pattern of conductor tracks buried under an elastomer protective layer, which connects contact areas on the active top side of the semiconductor chip to contact terminals which are arranged on elastomer elements embedded in the protective layer in a form-fitting manner. In addition, the document discloses a method for producing such electronic components.

US 2003/0233134 A1 discloses a biocompatible connection method and electronic package for implantation. The document relates to a method for connecting a hermetically sealed electronic package to an electrode or flexible circuit and the resulting electronic package suitable for implantation into living tissue, such as a retinal or cortical electrode array to enable restoration of vision in certain blind individuals. The hermetically sealed electronic package is directly connected to the flexible circuit or electrode by electroplating a biocompatible material, such as platinum or gold, creating a plated, rivet-like connection that connects the flexible circuit to the electronic package. The resulting electronic device is biocompatible and suitable for long-term implantation into living tissue.

The present invention has for its object to provide an electrical contact arrangement for connecting a contact carrier and an associated mating contact carrier, which allows even densely packed contact arrays to be electrically connected in a reliable and mechanically stable manner.

Furthermore, it is the object of the invention to provide an associated electrical connector arrangement.

These objects are achieved by the subject matter of the independent patent claims. Advantageous developments of the present invention are the subject matter of several dependent patent claims.

The present invention is based on the idea that with the help of a spring-elastic contact element, both the distance between the contact carrier and the counter-contact carrier in a direction transverse to the surface defined by the contact carrier and the position of the contact element within this surface can be compensated. This reduces the mechanical forces acting on the contact element and the connection between the contact element and the counter-contact element. The long-term stability of the connection is thus increased and the probability of failures reduced.

• Herstellen des Kontaktträgers mit mindestens einem elektrisch leitfähigen Kontaktelement und mindestens einer Leiterbahn, die mit dem Kontaktelement verbunden ist,
• Bereitstellen des Gegenkontaktträgers, der mindestens ein elektrisch leitendes Gegenkontaktelement aufweist und Positionieren des Kontaktträgers, so dass das mindestens eine Kontaktelement und das mindestens eine Gegenkontaktelement übereinander ausgerichtet sind,
• Anbringen einer Isolierlage an dem Kontaktträger, so dass das Kontaktelement durch die Isolierlage hindurch ragt,
• Verbinden des mindestens einen Kontaktelements und des mindestens einen Gegenkontaktelements durch Einbringen eines elektrisch leitenden Verbindungsmaterials durch den Kontaktträger hindurch,
• wobei das mindestens eine Kontaktelement in einer Richtung entlang einer Richtung des Verbindens mit dem Gegenkontaktelement elastisch verformbar ist.

For example, a method for establishing an electrical connection between a contact carrier and an associated mating contact carrier comprises the following steps:

• Producing the contact carrier with at least one electrically conductive contact element and at least one conductor track connected to the contact element,
• Providing the counter-contact carrier, which has at least one electrically conductive counter-contact element, and positioning the contact carrier so that the at least one contact element and the at least one counter-contact element are aligned one above the other,
• Attaching an insulating layer to the contact carrier so that the contact element protrudes through the insulating layer,
• Connecting the at least one contact element and the at least one counter-contact element by introducing an electrically conductive connecting material through the contact carrier,
• wherein the at least one contact element is elastically deformable in a direction along a direction of connection with the mating contact element.

The method further comprises the step of producing the insulating layer as a separate part from a silicone material, wherein the insulating layer has at least one continuous recess for passing through the at least one electrically conductive contact element and is applied before the step of connecting the at least one contact element and the at least one counter-contact element. According to a further aspect of the present invention, such a prefabricated insulating layer can also be used advantageously in conjunction with non-resilient conventional contact elements, since the elasticity of the insulating layer is often sufficient to compensate for the forces that occur.

The use of such a prefabricated insulating layer, preferably made of a silicone material, as underfill material has a number of advantages that can also be used independently of the provision of a spring-elastic contact element.

On the one hand, a long-term stable connection can be created from the underfill to both the contact carrier and the counter-contact carrier, and the formation of cavities or bubbles can be prevented. Furthermore, it can prevent contamination from being incorporated and the adhesive connection of the individual components from coming loose. Because the prefabricated insulating layer is already inserted before the electrical connection is made, for example by ball bonding or soldering, all materials involved can be thoroughly cleaned and disinfected before they are connected to one another.

For example, the method further comprises the step of promoting adhesion by means of oxygen plasma treatment of at least one of the surfaces of the insulating layer and/or by applying uncured liquid silicone to at least one of the surfaces of the insulating layer.

This ensures a firm and hermetically sealed connection between the insulating layer and the contact carrier on the one hand and the insulating layer and the mating contact carrier on the other.

Advantageously, the hermetic connection to the insulating layer is made before the electrical contact is made, so that for each contact area of a contact element to a mating contact element, a space is formed that is closed off from neighboring contact areas. Contaminants that arise as a result of the electrical connection process cannot impair the mechanical coupling between the underfill and the adjacent surfaces.

The insulating layer is produced using, for example, stereolithography, compression molding or laser cutting. Laser cutting is particularly advantageous for silicone materials.

As an alternative to using a prefabricated film as an insulating layer, the resilient contact elements according to the invention can also be combined with liquid precursors of an underfill, which are introduced and then cured. In this case, the method comprises the step of introducing the insulating layer after the step of connecting the at least one contact element and the at least one counter-contact element as a not yet solidified precursor material between the contact carrier and the associated counter-contact carrier and the subsequent solidification, for example by exposure to heat or UV radiation.

The elastic deformability of the contact elements can be achieved in an advantageous manner by designing the at least one contact element as a spiral spring or as at least one cut-free spring arm. For example, suitable structures can be produced by etching a metallization layer of the contact carrier.

According to an advantageous embodiment of the present invention, the contact carrier is made of an electrically insulating carrier material with a structured metal layer embedded therein, wherein the at least one contact element is exposed on at least one surface.

Advantageously, the electrical contact between the contact element and the counter-contact element is made through the contact carrier using a ball bonding or soldering connection. For this purpose, the contact element is exposed on both surfaces so that the electrical connection material can contact the contact element on both sides.

The above-mentioned Microflex process is particularly suitable for the arrangement according to the invention. In this process, a flexible contact carrier is provided with metallized vias and positioned over the mating contact pads of a mating contact carrier in such a way that the mating contact pads are accessible through the vias. Then, using a bonding device, for example a conventional thermosonic wire bonder (ultrasound with temperature support), a gold bonding ball is bonded through the vias to the mating contact pad underneath and torn off. The thinner flexible contact carrier is thus riveted onto the rigid mating contact carrier and at the same time the electrical connection between the vias and the mating contact pads underneath is established.

Alternatively, instead of gold bonding balls, drops of suitable solder can be introduced through the vias onto the underlying mating contact pad.

The present invention relates to an electrical contact arrangement for connecting a contact carrier to a mating contact carrier, which is manufactured using the method explained above.

In particular, the electrical contact arrangement has an electrically conductive contact element that is connected to at least one conductor track arranged on the contact carrier. An electrically conductive counter-contact element is arranged on a counter-contact carrier, wherein the contact element and the at least one counter-contact element are aligned one above the other. An insulating layer is arranged on the contact carrier such that the contact element protrudes through the insulating layer. According to the present invention, the at least one contact element is elastically deformable in a direction along a direction of connection to the counter-contact element.

As explained above, this can ensure a particularly secure and long-term stable connection even under permanently humid environmental conditions.

So that an underfill, which is required for electrical insulation between the individual contact areas, can be applied before the electrical connection between the contact element and the counter-contact element is created, the underfill is formed according to an advantageous embodiment of the present invention by a prefabricated "dry" silicone mat which has at least one continuous recess for passing through the at least one electrically conductive contact element.

Alternatively, the insulating layer can also be formed by a silicone layer cast between the contact carrier and the counter-contact carrier. This variant has the advantage that the manufacturing process is shortened by one adjustment step and, in addition, a smaller underfill thickness can be achieved.

The advantages of the arrangement according to the invention are particularly evident when the contact carrier is formed by a flexible film and the counter contacts are formed by contact pads on a rigid counter contact carrier. This is a frequently used contact arrangement, for example, in the field of implantable electronic components.

Furthermore, the present invention also relates to an electrical connector arrangement which has a contact carrier and a mating contact carrier with at least one contact arrangement according to the present invention. According to an advantageous embodiment, the contact carrier is formed by a flexible conductor track carrier with electrically conductive structures embedded therein and the associated mating contact carrier is formed by a monolithic integrated circuit, a ceramic circuit carrier or a flip-chip interposer.

• 1a, 1b und 1c zeigen unterschiedliche perspektivische Ansichten bzw. Schnittbilder einer erfindungsgemäßen elektrischen Verbinderanordnung gemäß einem ersten Ausführungsbeispiel;
• 2 illustriert die Herstellung einer Isolierlage gemäß einem ersten Ausführungsbeispiel;
• 3a, 3b und 3c zeigen in perspektivischer Darstellung aufeinander folgende Schritte bei der Herstellung einer Verbinderanordnung gemäß der vorliegenden Erfindung;
• 4a bis 4e zeigen eine Draufsicht auf einen Kontaktträger bzw. auf jeweils ein Kontaktelement gemäß unterschiedlichen Ausführungsformen der vorliegenden Erfindung;
• 5a, 5b, 5c illustrieren eine erste Variante zur Herstellung eines Kontaktträgers gemäß der vorliegenden Erfindung;
• 6a, 6b, 6c illustrieren eine weitere Variante zur Herstellung eines Kontaktträgers gemäß der vorliegenden Erfindung;
• 7a, 7b, 7c illustrieren eine weitere Variante zur Herstellung eines Kontaktträgers gemäß der vorliegenden Erfindung;
• 8a, 8b, 8c illustrieren eine weitere Variante zur Herstellung eines Kontaktträgers gemäß der vorliegenden Erfindung;
• 9a und 9b stellen als Schnittdarstellung zwei vorteilhafte Ausführungsformen einer Verbinderanordnung gemäß der vorliegenden Erfindung gegenüber.

For a better understanding of the present invention, it is explained in more detail using the exemplary embodiments shown in the following figures. The same parts are provided with the same reference numerals and the same component designations. Furthermore, some features or combinations of features from the different embodiments shown and described can represent independent, inventive or inventive solutions in themselves. They show:

• 1a , 1b and 1c show different perspective views or sectional views of an electrical connector arrangement according to the invention according to a first embodiment;
• 2 illustrates the production of an insulating layer according to a first embodiment;
• 3a , 3b and 3c show, in perspective, successive steps in the manufacture of a connector assembly according to the present invention;
• 4a to 4e show a plan view of a contact carrier or a contact element according to different embodiments of the present invention;
• 5a , 5b , 5c illustrate a first variant for producing a contact carrier according to the present invention;
• 6a , 6b , 6c illustrate a further variant for producing a contact carrier according to the present invention;
• 7a , 7b , 7c illustrate a further variant for producing a contact carrier according to the present invention;
• 8a , 8b , 8c illustrate a further variant for producing a contact carrier according to the present invention;
• 9a and 9b compare two advantageous embodiments of a connector arrangement according to the present invention in sectional representation.

With reference to the 1a , 1b , and 1c The principle of the connector arrangement 100 according to a first advantageous embodiment of the present invention will be explained in more detail below. 1a shows a perspective view of a connector assembly 100. 1b shows a detailed view of a contact arrangement in which the contact element is not cut, while 1c a section through the contact arrangement of the 1b shows.

As in the 1a to 1c As shown, the connector assembly 100 comprises a contact carrier 102 and a counter contact carrier 104. The contact carrier 102 is made of a flexible material, for example a polyimide film, and comprises a plurality of contact elements 106. Each contact element 106 is connected to a conductor track (not visible in the figures) which leads to an external contact arrangement (not visible in 1 ). These can be, for example, implantable electrodes.

According to the present invention, the mating contact carrier 104 is made of a rigid material. The mating contact carrier 104 can be formed, for example, by a monolithic integrated circuit, a ceramic circuit carrier or a flip-chip interposer.

As is known, large chips that have a large number of connections are connected to a circuit board via such interposers. The interposer serves to adapt the narrow connection grid of the chip to the larger connections of a circuit board. On the side facing the chip, such an interposer carries, for example, small solder balls (so-called bumps) to which the chip is soldered with its connections. According to the present invention, the interposer is connected to the contact carrier 102.

Irrespective of the other design and function, the counter-contact carrier 104 is provided with counter-contact elements 108. The counter-contact elements 108 are formed, for example, by contact pads, the arrangement of which corresponds to the layout of the contact elements 106 of the contact carrier 102. The contact carrier 102 is thus positioned with respect to the counter-contact carrier 104 such that the contact elements 106 are each arranged directly above the counter-contact elements 108.

In the Microflex Interconnection (MFI) technology used according to the invention, the contact elements 106 are connected to one another in an electrically conductive and mechanically fixed manner through the contact carrier 102 via electrically conductive connecting elements 110. The connecting elements The elements 110 can be made of gold balls (so-called “bumps”) or solder balls. Other metals or electrically conductive plastics can of course also be used.

According to an advantageous embodiment of the present invention, the contact elements 106 each have a spring-elastic region 112. By introducing the connecting element 110 using the bonder tip 116 in the direction of the arrow 114, the spring-elastic region 112 of the contact element 106 is deflected in the direction of the mating contact carrier 104. In the present example, the spring-elastic region 112 is formed by a spiral. Because the bump 110 tapers upwards, the spiral in the lower region is firmly connected to the gold bump 110 and thus also to the mating contact element 108. In the region connected to the contact carrier 102, however, the spiral is still movable, so that the contact carrier 102 is flexibly mounted with respect to the mating contact carrier 104. In this way, compensation of mechanical forces acting on the contact arrangement is made possible.

According to the invention, the connector arrangement 100 further comprises an insulating mat, for example made of silicone, which is arranged as an electrically insulating underfill 118 between the contact carrier 102 and the mating contact carrier 104 before the connecting elements 110 are attached.

According to the present invention, the spring-deflected contact elements of the contact carrier can be directly electrically connected to the metallization on the rigid counter-contact carrier, for example by using a gold rivet, e.g. according to the Microflex principle, a solder ball or a conductive paste as the connecting element 110. In the embodiment shown, a Microflex method is shown as an example. The tip of the bonder 116 presses the molten gold onto the flexible part of the flexible contact element in the direction of the corresponding contact pad 108 on the rigid counter-contact carrier 104, while the permissible mechanical load limits are observed. In this way, the contact element 104 and the counter-contact element 108 are mechanically and electrically connected to one another via thermocompression after the molten gold has solidified as the connecting element 110.

As can be seen from the side view and the cross-section of the 1b and 1c As can be seen, the connecting element 110 stretches the spiral spring in the direction of the associated mating contact element 108 of the rigid mating contact carrier 104. The flexible region 112 of the contact element 106 is partially covered with the bonding material.

The deflection of the compliant contact element 106 can be limited by providing the mating contact elements 108 on the rigid mating contact carrier 104 with additional solder or gold bumps before the flexible contact carrier is aligned with its contact array (not shown in the figures). A further bump can be provided on each pad to ensure the electrical connection between the contact element and the counter contact element in addition to the mechanical connection. However, by using rivet-like designs of the connecting elements, such a second bonding step is unnecessary.

The compliant nature of the contact arrangement according to the invention not only mechanically decouples adjacent contact arrangements, but also minimizes the overall mechanical stress that occurs in the flexible array during and after bonding. A final encapsulation of the connector arrangement 100, for example with a silicone material, can further improve the long-term stability and reliability of the connector arrangement 100.

According to a further aspect of the present invention, a prefabricated underfill 118, preferably made of silicone, is inserted between the contact carrier 102 and the mating contact carrier 104. Such an underfill, which can also be referred to as an insulating layer and is explained in detail below, can also be provided independently of the resilient design of the contact elements. Maximum mechanical decoupling and thus long-term stability of the connector arrangement is achieved by combining these two aspects.

According to an advantageous embodiment of the present invention, the underfill 118 is prefabricated as a separate film (or mat) and arranged between the contact carrier 102 and the counter-contact carrier 104 before the connecting elements 110 are attached. As can be seen from the 1a to 1c As can be seen, the underfill 118 has an array of continuous recesses 120. The underfill 118 is positioned such that a recess 120 is arranged between a counter contact element 108 and a contact element 106 and a part of the contact element 106 protrudes through the recess 120 after the connection elements 110 have been attached.

By using such a "dry" insulating film instead of the otherwise usual liquid underfills, a long-term stable, bubble- and cavity-free insulating layer can be produced, which also minimizes the incorporation of contaminants by being installed as a protective intermediate layer before the connecting elements 110 are attached.

Further details of the Underfill 118 and its manufacture are described below with reference to the 2 and 3 explained. As 2 As can be seen, according to an advantageous embodiment of the present invention, the underfill 118 is produced in a similar way to a silicone seal from a PDMS film (or mat), which is initially produced without recesses 120 using stereo photolithography, as a molded piece or by laser cutting. In a further work step, the recesses 120 are made in the required positions. This can be done, for example, by a laser cutting process using a laser generator 122. The laser beam 124 is guided over the surface of the PDMS film in a computer-controlled manner, as is generally known.

The PDMS film can be produced, for example, by spinning a corresponding liquid precursor onto a flat substrate, waiting until the solvents have evaporated for solidification. The quality of the PDMS film can be further improved if the liquid silicone precursor is subjected to treatment in a vacuum centrifuge before spinning or immediately after.

Alternatively, the recesses 120 can also be formed directly during manufacture in a negative mold using corresponding projections or stamp structures (the casting molds are not shown in the figures).

However, it is clear to a person skilled in the art that other electrically insulating materials can also be used as prefabricated underfill 118, in particular other plastics, provided they have the required stability for use in aqueous media.

The 3a to 3c illustrate the assembly of the contact carrier 102 and the counter contact carrier 104 with the underfill 118. According to an advantageous embodiment of the present invention, the contact carrier 102 is formed by a flexible printed circuit board in which contact elements 102 are connected to conductor tracks (not visible in the figures).

For example, the contact carrier 102 can be part of an implantable electrode array. The electrically conductive structures are covered by an insulating layer 126 that is open in the area of the contact elements 102. As will be explained in more detail later, the conductive structures of the contact carrier are produced as a metallization layer with electrodes, connection pads and conductor tracks embedded in a polymer, for example polyimide. Adhesive layers, for example silicon carbide and so-called diamond-like carbon (DLC) in the case of polyimide, ensure the connection between the metal and the plastic layer. Furthermore, the outer surface of the contact carrier 102 can be provided with an adhesive that improves the adhesion between the contact carrier 102 and the PDMS underfill 118. Suitable compounds here are, for example, a combination of silicon carbide and silicon dioxide.

The mating contact carrier 104 is formed by a rigid component, such as an electronic component, an interposer or a ceramic substrate. At least one of the surfaces of the mating contact carrier 104 is provided with mating contact elements 108, which at least partially correspond to the contact elements 106 to which they are to be connected. These can be, for example, metallic contact spots (also referred to as contact pads). The underfill 118 is manufactured separately, as described with reference to 2 explained, and arranged between the contact carrier 102 and the mating contact carrier 104 such that the recesses 120 form a passage from the contact elements 106 to the mating contact elements 108.

The stable and permanent adhesion of the underfill 118 to the flexible contact carrier 102 on the one hand and the rigid counter-contact carrier 104 on the other hand is essential for the long-term stability of the finished connector arrangement 100 and thus for its usability as an implant. This can be achieved, for example, by forming a SiC-SiO ₂ adhesion promoter layer on the insulating layer 126 of the contact carrier 102, as mentioned above. A further adhesion promoter layer can be provided on the surface of the rigid counter-contact carrier 104 provided with the counter-contact elements 108. For example, a corresponding glaze layer can be printed onto the surface of the counter-contact carrier 104.

As shown by the sequence of 3a to 3c illustrated, the prefabricated underfill 118 can advantageously be mounted on the rigid counter-contact carrier 104 and the recesses 120 can be aligned with respect to the counter-contact element 108. Of course, the contact carrier 102 and the underfill 118 can also be adjusted with respect to one another first. In any case, all surfaces must first be cleaned and activated with cleaning agents and oxygen plasma. The oxygen plasma activates the surface of the silicone rubber sheet and thereby improves its ability to bond. It is also possible to apply a thin layer of uncured liquid silicone to the surface of the underfill 118 in order to activate it.

The 3a to 3c The illustrated assembly of the contact carrier 102, the counter-contact carrier 104 and the underfill 118, which takes place before the connecting elements 110 are introduced, has the advantage that a thorough cleaning of the surfaces to be joined can take place before each joining step. As a result, a cavity- and contamination-free mechanical connection of the underfill 118 to both the rigid counter-contact carrier arrangement 104 and to the flexible contact carrier 102 can be produced before the actual electrical connection between the contact element 106 and the counter-contact elements 108 is formed.

In the 3c The arrangement shown is the starting point for the 1a bonding step shown. As with reference to 1a until 1c As already explained, the contact elements 106 have spring-elastic regions 112 which can be deflected in the direction of the mating contact carrier 104 and thereby penetrate through the recesses 120 in the underfill 118.

The 4a to 4e illustrate various embodiments of the spring-elastic region 112 of the contact element 106. 4a the in 1 and 3 shown contact carrier 102 in a representation rotated by 180°, so that the side of the contact carrier 102 facing the counter contact carrier 104 is visible. The 4b to 4e show various designs of the contact element 106 as a detailed view.

As in 4a and the detailed view of the 4e As can be seen, the spring-elastic region 112 of the contact element 106 can be designed as a spiral spring that can be deflected out of the plane of the drawing. This spiral spring makes it possible to establish an electrical connection between the contact element 106 and the corresponding counter-contact element 108 using a thermocompression bonding process, a soldering process, a riveting process or a bonding process that uses a conductive paste. A predetermined vertical height (ie a predetermined initial distance between the region of the contact element 106 that is firmly connected to the contact carrier 102 and the deflected end of the flexible region 112) can be specified in the flexible spring structure of the contact element 106 by appropriate manufacturing processes.

As in 4b As shown, cantilevered segments can be provided as spring-elastic regions 112 by providing a cross-shaped opening 128 in the contact element 106.

Furthermore, spring arms cut free on one side can also be provided as spring-elastic areas 112, as shown in 4c is shown.

Another example of the spring-elastic area 112 is in 4d shown. Here, three spiral spring arms are connected to one another at a central contact point 130. Other suitable configurations of the spring-elastic region can of course also be provided within the scope of the present invention.

All these configurations can be used for the 1a to 1c shown connector arrangement 100 can be used. In particular in conjunction with an elastic underfill 118, preferably made of silicone, the springy design of the contact elements 106 according to the invention enables a mechanical decoupling of adjacent contact arrangements. This is particularly advantageous in the case of closely packed contact arrays. Furthermore, the springy areas serve to compensate for mechanical loads and to compensate for tolerances, in particular in the underfill thickness. This increases the long-term stability and durability of the electrical connection between the contact carrier and the mating contact carrier.

With reference to the 5 to 8 Various concepts for producing the flexible contact carrier 102 will be explained in more detail below.

According to a first advantageous embodiment, as in 5a shown, a flexible printed circuit (FPC) 134, also referred to as a flexible flat cable (FFC), is fixed to a carrier wafer 132. The flexible circuit carrier 134 comprises a metallization layer 136, which is made of platinum, for example. The metallization is 136 is embedded, for example, in a polyimide insulation 138. Silicon carbide layers and/or DLC layers (diamond like carbon), for example, can be provided to promote adhesion between the metallization 136 and the polyimide insulation layer 138. A double layer of DLC and SiO ₂ is applied as an adhesion promoter layer 146 and removed again from the exposed metallization regions 142 and 144, for example by an etching step. The adhesion promoter layers 146 improve the adhesion of the contact carrier 102 to the underfill 118.

As shown schematically in 5a As shown, the metallization layer 136 has first regions 140 that are completely enclosed in the polyimide and form the conductor tracks. Second regions 142 are exposed, for example, using a photo technique and represent the regions that function as electrodes. Third regions 144 are finally designed as spring-elastic contact elements 106.

For the production of the contact carrier 102, the next step is to 5b shows, the carrier wafer 132 is detached and the flexible circuit carrier 134 is turned over. The now in 5b An adhesion promoter layer 146 is applied to the upper surface of the flexible circuit carrier 134 (see 5c ).

The flexible regions of the contact elements 106 are preferably produced in a photolithographic process during the metallization step.

The 6a to 6c show a second advantageous embodiment for producing the flexible contact carrier 102 according to the invention. As in 6a As shown, thermally grown silicon dioxide and silicon carbide are first deposited on a sacrificial polymer layer 148. The silicon carbide can be deposited, for example, using a plasma-enhanced CVD process (plasma enhanced chemical vapor deposition, PECVD). The sacrificial polymer layer 148 is in turn produced on a removable carrier wafer 132.

The flexible circuit carrier 134 is now applied layer by layer and provided with a further double layer of adhesion promoter 146.

6c shows the finished contact carrier 102 after removal of the carrier wafer 132 and the sacrificial polymer layer 148. If necessary, cleaning, for example by means of oxygen plasma, may be necessary after removal of the carrier wafer 132 and the sacrificial polymer layer 148.

The contact elements 106 according to the invention are manufactured according to 5 and 6 for example, by depositing metal on a planar polymer substrate. Their resilient regions 112 are formed by appropriate structuring.

Alternatively, contact elements 106 can also be manufactured with a pre-determined distance to the flat plane of the counter contact carrier 104. A first possibility for producing a flexible contact arrangement with a predetermined height is shown in 7 shown.

To produce projections 150, which in the later assembled state come into contact with the counter contact carrier 104, according to 7a a carrier wafer 132 is provided with etching pits 152 which act as a negative mold, so that the polyimide 138 forms a cushion-shaped projection 150. After removing the carrier wafer 132, a silicon dioxide layer is preferably applied as an adhesion promoter layer 146, which enables a secure connection to the mating contact carrier 104.

As in 8a to 8c As shown, it can also be provided that the metallization (for example made of platinum) in the region of the contact elements 106 follows the contour of the projection 150.

According to the invention, the projections 150 are immersed in the recesses 120 in the underfill 118 and can further reduce mechanical stress when establishing the electrical connection and during subsequent operation. In addition, the contact carrier can be designed in the 8th can also be combined with a conventional liquid underfill, which is drawn between the contact carrier 102 and the mating contact carrier 104 via capillary forces.

The 9a and 9b make the contact arrangement with a “dry” and a “liquid” underfill using contact carrier 102 8th towards each other.

9a shows a connector assembly 100 having a flexible contact carrier 102 according to 8c The counter contact carrier 104 has embedded, flat contact pads as counter contact elements 108. A prefabricated underfill 118 is arranged between the contact carrier 102 and the counter contact carrier 104 such that the projections 150 with the contact elements 106 protrude through the recesses 120 in the direction of the rigid counter contact carrier 104. The contact elements thereby compensate for the thickness of the prefabricated underfill 118. Connecting elements 110 provide (as with reference to 1 explained) establishes the electrical and mechanical connection between the contact carrier 102 and the mating contact carrier 104.

9b shows the alternative embodiment in which no prefabricated underfill 118 is inserted between the flexible contact carrier 102 and the rigid counter-contact carrier 104. Rather, the gap formed between the underside of the contact carrier 102 and the top of the counter-contact carrier 104 facilitates the introduction of an initially liquid sigen Underfills 154, which is introduced after bonding in the form of a liquid precursor and then cured. Solidification occurs, for example, through the application of heat or UV radiation.

The connecting elements 110 correspond to the previously explained embodiments of the electrical connection between the contact elements 106 and the mating contact elements 108.

• Herstellen des Kontaktträgers 102 mit mindestens einem elektrisch leitfähigen Kontaktelement 106 und mindestens einer Leiterbahn, die mit dem Kontaktelement verbunden ist,
• Bereitstellen des Gegenkontaktträgers 104, der mindestens ein elektrisch leitendes Gegenkontaktelement 108 aufweist und Positionieren des Kontaktträgers 102, so dass das mindestens eine Kontaktelement 106 und das mindestens eine Gegenkontaktelement 108 übereinander ausgerichtet sind,
• Anbringen einer Isolierlage 118, 154 zwischen dem Kontaktträger 102 und dem Gegenkontaktträger 104, so dass das Kontaktelement 106 durch die Isolierlage 118, 154 hindurch ragt,
• Verbinden des mindestens einen Kontaktelements 106 und des mindestens einen Gegenkontaktelements 108 durch Einbringen eines elektrisch leitenden Verbindungsmaterials 110 durch den Kontaktträger 102 hindurch,
• wobei das mindestens eine Kontaktelement 106 entlang einer Richtung 114 des Verbindens mit dem Gegenkontaktelement 104 elastisch verformbar ist.

The present disclosure thus provides a method for establishing an electrical connection between a contact carrier 102 and an associated mating contact carrier 104, the method comprising the following steps:

• Producing the contact carrier 102 with at least one electrically conductive contact element 106 and at least one conductor track connected to the contact element,
• Providing the counter-contact carrier 104, which has at least one electrically conductive counter-contact element 108 and positioning the contact carrier 102 so that the at least one contact element 106 and the at least one counter-contact element 108 are aligned one above the other,
• Attaching an insulating layer 118, 154 between the contact carrier 102 and the counter-contact carrier 104, so that the contact element 106 protrudes through the insulating layer 118, 154,
• Connecting the at least one contact element 106 and the at least one counter-contact element 108 by introducing an electrically conductive connecting material 110 through the contact carrier 102,
• wherein the at least one contact element 106 is elastically deformable along a direction 114 of connection to the mating contact element 104.

According to a further aspect, the method further comprises the step of producing the insulating layer 118 as a separate part from a silicone material, wherein the insulating layer 118 has at least one continuous recess 120 for passing through the at least one electrically conductive contact element 106 and is applied before the step of connecting the at least one contact element 106 and the at least one counter-contact element 108.

• Herstellen des Kontaktträgers 102 mit mindestens einem elektrisch leitfähigen Kontaktelement 106 und mindestens einer Leiterbahn, die mit dem Kontaktelement 106 verbunden ist,
• Bereitstellen des Gegenkontaktträgers 104, der mindestens ein elektrisch leitendes Gegenkontaktelement 108 aufweist und Positionieren des Kontaktträgers 102, so dass das mindestens eine Kontaktelement 106 und das mindestens eine Gegenkontaktelement 108 übereinander ausgerichtet sind,
• Herstellen der Isolierlage 118 als separates Teil vorzugsweise aus einem Silikonmaterial, wobei die Isolierlage 118 mindestens eine durchgehende Ausnehmung 120 zum Hindurchführen des mindestens einen elektrisch leitfähigen Kontaktelements 106 aufweist,
• Anbringen der Isolierlage 118 zwischen dem Kontaktträger 102 und dem Gegenkontaktträger 104, so dass das Kontaktelement durch die Isolierlage 118 hindurch ragt, anschließendes Verbinden des mindestens einen Kontaktelements 106 und des mindestens einen Gegenkontaktelements 108 durch Einbringen eines elektrisch leitenden Verbindungsmaterials 110 durch den Kontaktträger hindurch.

Furthermore, a method for establishing an electrical connection between a contact carrier 102 and an associated mating contact carrier 104 is specified, the method comprising the following steps:

• Producing the contact carrier 102 with at least one electrically conductive contact element 106 and at least one conductor track connected to the contact element 106,
• Providing the counter-contact carrier 104, which has at least one electrically conductive counter-contact element 108 and positioning the contact carrier 102 so that the at least one contact element 106 and the at least one counter-contact element 108 are aligned one above the other,
• Producing the insulating layer 118 as a separate part, preferably from a silicone material, wherein the insulating layer 118 has at least one continuous recess 120 for passing through the at least one electrically conductive contact element 106,
• Attaching the insulating layer 118 between the contact carrier 102 and the mating contact carrier 104 so that the contact element protrudes through the insulating layer 118, then connecting the at least one contact element 106 and the at least one mating contact element 108 by introducing an electrically conductive connecting material 110 through the contact carrier.

According to a further aspect, the at least one contact element 106 is elastically deformable along a direction of connection with the mating contact element 108.

According to a further aspect, the method further comprises the step of promoting adhesion by means of oxygen plasma treatment of at least one of the surfaces of the insulating layer 118 and/or by applying uncured liquid silicone to at least one of the surfaces of the insulating layer 118.

In another aspect, the insulating layer 118 is manufactured using stereolithography, compression molding, or laser cutting.

According to a further aspect, after the step of connecting the at least one contact element 106 and the at least one counter-contact element 108, the insulating layer 154 is introduced as a not yet solidified precursor material between the contact carrier and the associated counter-contact carrier and is then solidified.

According to a further aspect, the at least one contact element 106 is designed as a spiral spring or as at least one cut-free spring arm.

According to a further aspect, the contact carrier is made of an electrically insulating carrier material 126, 138 having a structured metal layer embedded therein, and wherein the at least one contact element 106 is exposed on at least one surface.

According to a further aspect, the at least one contact element 106 is exposed on both surfaces and the method further comprises the step of electrically ball bonding or soldering through the contact carrier.

• ein elektrisch leitfähiges Kontaktelement 106, das mit mindestens einer an dem Kontaktträger 102 angeordneten Leiterbahn verbunden ist,
• ein elektrisch leitendes Gegenkontaktelement 108, das an einem Gegenkontaktträger 104 angeordnet ist, wobei das Kontaktelement 106 und das mindestens eine Gegenkontaktelement 108 übereinander ausgerichtet sind,
• eine Isolierlage 118, 154, die so zwischen dem Kontaktträger 102 und dem Gegenkontaktträger 104 angeordnet ist, dass das Kontaktelement 106 durch die Isolierlage 118, 154 hindurch ragt,
• wobei das mindestens eine Kontaktelement 106 entlang einer Richtung 114 des Verbindens mit dem Gegenkontaktelement 108 elastisch verformbar ist.

The present disclosure also provides an electrical contact arrangement for connecting a contact carrier 102 to a mating contact carrier 104, the contact arrangement comprising:

• an electrically conductive contact element 106 which is connected to at least one conductor track arranged on the contact carrier 102,
• an electrically conductive counter-contact element 108 which is arranged on a counter-contact carrier 104, wherein the contact element 106 and the at least one counter-contact element 108 are aligned one above the other,
• an insulating layer 118, 154, which is arranged between the contact carrier 102 and the counter-contact carrier 104 such that the contact element 106 protrudes through the insulating layer 118, 154,
• wherein the at least one contact element 106 is elastically deformable along a direction 114 of connection to the mating contact element 108.

The insulating layer 118 can be formed by a prefabricated silicone mat which has at least one continuous recess 120 for passing through the at least one electrically conductive contact element 106.

• ein elektrisch leitfähiges Kontaktelement 106, das mit mindestens einer an dem Kontaktträger 102 angeordneten Leiterbahn verbunden ist,
• ein elektrisch leitendes Gegenkontaktelement 108, das an einem Gegenkontaktträger 104 angeordnet ist, wobei das Kontaktelement 106 und das mindestens eine Gegenkontaktelement 108 übereinander ausgerichtet sind,
• eine Isolierlage 118, die so zwischen dem Kontaktträger 102 und dem Gegenkontaktträger 104 angeordnet ist, dass das Kontaktelement 106 durch die Isolierlage 118 hindurch ragt,
• wobei die Isolierlage 118 durch eine vorgefertigte Silikonmatte gebildet ist, die mindestens eine durchgehende Ausnehmung 120 zum Hindurchführen des mindestens einen elektrisch leitfähigen Kontaktelements 106 aufweist.

The present disclosure further provides an electrical contact arrangement for connecting a contact carrier 102 to a mating contact carrier 104, the contact arrangement comprising:

• an electrically conductive contact element 106 which is connected to at least one conductor track arranged on the contact carrier 102,
• an electrically conductive counter-contact element 108 which is arranged on a counter-contact carrier 104, wherein the contact element 106 and the at least one counter-contact element 108 are aligned one above the other,
• an insulating layer 118 which is arranged between the contact carrier 102 and the counter-contact carrier 104 such that the contact element 106 protrudes through the insulating layer 118,
• wherein the insulating layer 118 is formed by a prefabricated silicone mat which has at least one continuous recess 120 for passing through the at least one electrically conductive contact element 106.

According to a further aspect, the at least one contact element 106 is elastically deformable along a direction 114 of connection to the mating contact element 108.

According to a further aspect, the insulating layer 154 is formed by a silicone layer cast between the contact carrier 102 and the mating contact carrier 104.

According to a further aspect, the contact carrier 102 is formed by a flexible film and the mating contacts 108 are formed by contact pads on a rigid mating contact carrier 104.

According to a further aspect, an electrical connector arrangement 100 has a contact carrier 102 and a mating contact carrier 104 with at least one contact arrangement.

According to a further aspect, the contact carrier 102 is formed by a flexible conductor carrier with electrically conductive structures embedded therein.

According to a further aspect, the mating contact carrier 104 is formed by a monolithic integrated circuit, a ceramic circuit carrier or a flip-chip interposer.

List of reference symbols:

100

Connector arrangement

102

Contact carrier

104

Counter contact carrier

106

Contact element

108

Counter contact element

110

Fastener, bump

112

Spring elastic area

114

Bond direction

116

Bonder tip

118

Prefabricated underfill

120

Recesses in the underfill

122

Laser generator

124

laser beam

126

Insulating layer of the contact carrier

128

Cross-shaped opening

130

Contact point

132

Carrier wafer

134

flexible printed circuit (FPC), flexible cable (flexible flat cable, FFC)

136

Metallization layer

138

Polyimide insulation

140

First area of the metallization layer

142

Second area of the metallization layer

144

Third area of the metallization layer

146

Adhesion promoter layer

148

Sacrificial polymer layer

150

head Start

152

Etching pit

154

Liquid underfill

Claims (10)

Electrical contact arrangement for connecting a contact carrier (102) to a mating contact carrier (104), the contact arrangement comprising: an electrically conductive contact element (106) which is connected to at least one conductor track arranged on the contact carrier (102), an electrically conductive mating contact element (108) which is arranged on a mating contact carrier (104), the contact element (106) and the at least one mating contact element (108) being aligned one above the other, an insulating layer (118, 154) which is arranged between the contact carrier (102) and the mating contact carrier (104) such that the contact element (106) protrudes through the insulating layer (118, 154), the at least one contact element (106) being elastically deformable along a direction (114) of connection to the mating contact element (108), the contact carrier (102) being made of an electrically insulating carrier material (126, 138) with a structured metal layer embedded therein and wherein the contact element (106) is exposed on both surfaces so that it can be connected in an electrically conductive and mechanically fixed manner through the contact carrier (102) via an electrically conductive connecting element (110) to the associated electrically conductive mating contact element (108). Electrical contact arrangement according to Claim 1 , wherein the insulating layer (118) is formed by a prefabricated silicone mat which has at least one continuous recess (120) for passing through the at least one electrically conductive contact element (106). Electrical contact arrangement according to one of the Claims 1 or 2 , wherein the contact carrier (102) is formed by a flexible film and the mating contacts (108) are formed by contact pads on a rigid mating contact carrier (104). Electrical contact arrangement according to one of the preceding claims, further comprising an adhesion promoter on at least one of the surfaces of the insulating layer (118). Electrical contact arrangement according to one of the preceding claims, wherein the insulating layer (118) is manufactured by means of stereolithography, compression molding or laser cutting. Electrical contact arrangement according to one of the preceding claims, wherein the at least one contact element (106) is designed as a spiral spring or as at least one cut-free spring arm. Electrical contact arrangement according to one of the preceding claims, wherein the at least one connecting element (110) has a ball bond connection or a solder connection. Electrical connector arrangement, wherein the connector arrangement (100) comprises a contact carrier (102) and a mating contact carrier (104) with at least one contact arrangement according to one of the Claims 1 until 7 having. Electrical connector arrangement according to Claim 8 , wherein the contact carrier (102) is formed by a flexible conductor carrier with electrically conductive structures embedded therein. Electrical connector arrangement according to Claim 8 or 9 , wherein the mating contact carrier (104) is formed by a monolithic integrated circuit, a ceramic circuit carrier or a flip-chip interposer.

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