Methods for electrically contacting a component and component assembly

Abstract

Method for electrically contacting a component (1), wherein the component (1) is arranged on a circuit carrier (10) having a first connection area (11), wherein the first connection area (11) is connected to a second connection area (3) of the component (1) by means of an electrically conductive layer (21), wherein the electrically conductive layer (21) is applied by jet injection, and wherein the component (1) is fixed to the circuit carrier (10) by means of a curable fixing layer (16) in the form of an electrically non-conductive adhesive, characterized in that the adhesive is applied to the circuit carrier (10) such that the height of the adhesive is greatest in the middle of the oppositely arranged first connection areas (11) and decreases towards the first connection areas (11) and is at its lowest height there.and that after the component (1) is placed on the adhesive, the adhesive extends to a top surface (2) of the component (1) at its lateral edge areas and a continuous, non-stepped transition area (19) is created between the connection areas (3, 11).

Description

State of the art

[0001] The invention relates to a method for electrically contacting a component according to the preamble of claim 1. Furthermore, the invention relates to an electrical or electronic component assembly produced using a method according to the invention.

[0002] A method for electrically contacting a component according to the preamble of claim 1 is known from DE 693 12 421 T2. In the known method, an electrically conductive adhesive is applied to a circuit carrier in the form of a printed circuit board, wherein the adhesive contacts a first electrical connection area of ​​the printed circuit board, in particular in the form of a conductor track. Subsequently, in a second step, an electrical component is connected to the circuit carrier by means of an electrically non-conductive adhesive, wherein second electrical connection areas of the component (connecting wires) contact the electrically conductive adhesive. The component assembly thus formed is then subjected to a treatment to cure the electrically conductive and electrically non-conductive adhesive.The aforementioned document mentions that the electrically conductive adhesive can be applied to the circuit board by spreading, screen printing, or other printing methods.

[0003] Furthermore, electronic components are known from the prior art according to DE 10 2011 003 195 A1, whose (second) connection areas are arranged on the top side of the component. This means that the first connection area of ​​the circuit carrier and the second connection area of ​​the component are at different (height) levels. To connect electrical connection areas that are horizontally spaced apart and also arranged at different levels, a process called wire bonding is used, in which a large number of electrical connections between a circuit carrier and a component can be made within a very short time using appropriate wire bonding machines.

[0004] Furthermore, it is also known from DE 10 2011 003 195 A1 to cover the circuit carrier in the area of ​​the electrical connections with an additional covering element in order to make this area more robust against the influence of media or pressure fluctuations. In practice, such a covering is achieved, for example, with a polymer, in particular a gel or similar material. Because the electrical connection (wire bond) between the two connection areas is, so to speak, suspended, the problem arises that air inclusions may occur, especially below the wire bond, which reduce the effectiveness of the protective measure. To prevent this, appropriate process monitoring or a relatively long process time for carrying out the covering is required.

[0005] Most recently, the so-called "aerosol jet process" (http: / / www.3d-mid.de) has emerged, which, in contrast to conventional screen and pad printing, where feature sizes of several hundred micrometers can be achieved on simple component geometries, allows for the creation of extremely fine structures in the range of well below 50 micrometers. The coating material, which is similar to an ink, is present as a liquid in an atomizer, where an aerosol is generated pneumatically or by ultrasound. This aerosol is applied to the substrate to be coated via a nozzle. The well-known aerosol jet process is thus used to create extremely fine conductive tracks.

[0006] DE 10 2009 045 948 A1 discloses a method for manufacturing an electrical or electronic component. WO 2007 / 042 071 A1 relates to an assembly with at least two components in an electrically conductive connection. WO 02 / 084 586 A1 discloses an electrical connection between a chip and a communication interface pad by depositing a liquid substance. Disclosure of the invention

[0007] Based on the prior art described above, the invention aims to further develop a method for electrically contacting a component according to the preamble of claim 1. Advantageously, this provides a manufacturing-economical and process-wise easily controllable method for connecting two electrical connection areas between a component and a circuit carrier. In a method with the features of claim 1, this is achieved by applying the electrically conductive layer using a jet process. Such a method has the particular advantage that the electrically conductive layer only needs to be applied precisely in the areas that serve for the electrical contacting of the two connection areas of the component and the circuit carrier.In particular, unlike the prior art mentioned at the outset, it is sufficient to apply the electrically conductive layer only to the immediate connection areas of the component and the circuit carrier, as well as to the corresponding connection between the two connection areas. A significant advantage is that the jet-applied process allows any existing level differences between the two connection areas to be easily overcome without creating a gap between the connection and, for example, the circuit carrier. This results in a particularly robust contact.

[0008] Advantageous further developments of the inventive method for electrically contacting a component are specified in the dependent claims.

[0009] In a preferred embodiment of the method according to the invention, the component is first mounted on the circuit carrier, and the electrically conductive layer is applied in a second step. This has the particular advantage that the second connection area of ​​the component is covered by the electrically conductive layer, so that this area is already protected from environmental influences by the electrically conductive layer itself. This may eliminate the need for additional protective measures (covering). Furthermore, this approach offers the advantage that, after the component is mounted on the circuit carrier, the final position of the (second) connection area of ​​the component is defined or fixed, so that a suitable automated system for applying the electrically conductive layer can be precisely controlled based on the actual position of the second connection area of ​​the component.

[0010] By applying the electrically conductive layer using the jet process according to the invention, different materials can be used as the electrically conductive layer. Aerosols or (electrically conductive) conductive adhesives are preferably suitable.

[0011] In a manufacturing-technically preferred embodiment of the component's attachment to the circuit carrier, the invention proposes that the attachment be effected by a curable fixing layer in the form of an electrically non-conductive adhesive. Such an electrically non-conductive adhesive can, through appropriate design, also ensure good heat transfer to the circuit carrier, thus reducing the thermal stress on the component during operation.

[0012] To fix the electrically conductive layer after its application, it is preferably provided that the electrically conductive layer is cured, in particular by a heat treatment.

[0013] As explained earlier, applying the electrically conductive layer using the jet method has the particular advantage that only a small area of ​​the electrically conductive layer is required to connect the two connection areas. Therefore, in a particularly preferred embodiment of the method, the electrically conductive layer is designed to cover the two connection areas only to a maximum extent and not to extend beyond them (except in the area of ​​the connection between the two connection areas). This allows for the reliable contact of very closely spaced connection areas of the component without the risk of short circuits.

[0014] The invention also includes a component assembly. Preferably, the component assembly consists of a circuit carrier having a first connection area and a component having a second connection area, wherein the two connection areas are connected to each other by means of an electrically conductive layer, which is applied in particular according to a method according to the invention. In particular, it is provided that the two connection areas are arranged at different levels and horizontally spaced apart from each other with respect to the plane of the circuit carrier, and that the transition between the two levels is continuous, at least in the area of ​​the electrically conductive layer.The continuous transition of the electrically conductive layer between the two connection areas avoids, in particular, material accumulations of the electrically conductive layer that would otherwise be necessary in the case of a discontinuous transition to ensure a continuous electrical connection between the two connection areas.

[0015] It is particularly preferred if the continuous transition between the two levels of the connection areas is formed by a fixing layer for the component on the circuit carrier. This eliminates the need for an additional component or any special design of the component to enable the continuous transition. Instead, this transition is formed by the curable fixing layer required to attach the component to the circuit carrier.

[0016] To provide particularly good protection for the component assembly against environmental influences or pressure fluctuations, the component area, the electrically conductive layer, and the two connection areas on the circuit carrier can be covered by a protective layer. Such a protective layer preferably consists of a polymer (e.g., a lacquer, a molding compound, or similar). After the protective layer has formed, the component assembly can be subjected to further (thermomechanical) stress, possibly through temperature changes, to improve quality.

[0017] The method according to the invention is particularly advantageous when using ICs or ASICs. Such ICs or ASICs typically have a plurality of (secondary) connection areas that are arranged close together. By using the jet method to apply the electrically conductive layer, short circuits between the electrically conductive layers and the different connection areas are particularly avoided.

[0018] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing.

[0019] This shows in the Fig. Figures 1 to 7 show in cross-section the connection area between an electronic component and a printed circuit board during different phases for establishing the contacting of the component according to the invention.

[0020] Identical elements or elements with the same function are provided with the same reference numbers in the figures.

[0021] The figures show a circuit carrier 10, in particular in the form of a printed circuit board, which serves as a component carrier for an electronic component 1. The component 1 is preferably, but not exclusively, a component 1 comprising an electronic circuit in the form of an IC, ASIC, or similar. The circuit carrier 10 has at least one, but in practice several, first connection areas 11 in a connection area for the component 1, which can be designed, for example, in the form of conductor tracks, lands, or similar. The component 1 has, as shown by the Fig. 3 to 7 is recognizable, on its upper side 2 corresponding to the number of first connection areas 11 and assigned second connection areas 3, which may be formed, for example, in the form of a partial coating or similar.

[0022] According to the Fig. 2 In a first process step, an electrically non-conductive fixing layer 16, in particular in the form of an adhesive, is applied to the connection area between the component 1 and the circuit carrier 10 by means of a suitable device 15 to contact the component 1. In the illustrated embodiment, the amount or height of the applied adhesive or fixing layer 16 differs between the opposing first connection areas 11 on the circuit carrier 10, such that the fixing layer 16 has the greatest height or thickness in the middle between the two first connection areas 11, and the height or thickness of the fixing layer 16 decreases towards the first connection areas 11, preferably such that the first fixing layer 16 extends almost to the first connection area 11, but has only a minimal height or thickness there.

[0023] Then, according to the Fig. 3. The component 1 is placed onto the fixing layer 16 and, if necessary, positioned with a defined contact force. By placing the component 1 onto the fixing layer 16, the fixing layer 16 is displaced, with the result that the fixing layer 16 preferably extends to the top surface 2 of the component 1 at its lateral edge regions and is furthermore displaced directly to the first connection areas 11 of the circuit carrier 10, such that a continuous, i.e., non-stepped, transition area 19 is created between the two connection areas 3, 11 of the circuit carrier 10 and of the component 1, which are arranged at different levels with respect to the circuit carrier 10.

[0024] To fix component 1 to the circuit carrier 10, the following steps are taken: Fig. 4. The fixing layer 16 is then cured, preferably by heat treatment, as indicated by the heat arrows 17. In a step following the curing of the fixing area 16, an electrically conductive layer 21 in the form of a conductive adhesive or an aerosol is applied or sprayed between the connection areas 3 and 11 by means of an application or spraying device 20, which is movably arranged at least in the horizontal plane of the circuit carrier 10, but preferably also perpendicular to the plane of the circuit carrier 10, using a jet process. Fig. 5) In the illustrated embodiment, the spray device 20 is first positioned in the area of ​​a first connection area 11, and the spray device 20 is activated so that the electrically conductive layer 21 is applied to the top surface of the first connection area 11. A subsequent horizontal and, if necessary, vertical movement of the spray device 20 connects the first connection area 11 to the associated second connection area 3 on the top surface 2 of the component 1, as shown by the Fig. Figure 6 shows this process. This occurs gradually at all connection areas 3, 11. In the illustrated embodiment, the electrically conductive layer 21 completely covers the second connection area 3 of the component 1 and also extends beyond the second connection area 3 on the side facing away from the first connection area 11.

[0025] Then, according to the Fig. 6, preferably by a heat treatment, which is to be illustrated by the heat arrows 18, the electrically conductive layer 21 is hardened.

[0026] Finally, it may optionally be provided that, according to the Fig. 7 The component assembly 25, consisting of component 1, circuit carrier 10 and electrically conductive layer 21, is covered by a protective layer 22 at least in the area of ​​component 1 and the connection areas 3, 11 and the electrically conductive layer 21. The protective layer 22 preferably consists of a polymer or similar material.

[0027] The method described so far can be adapted or modified in various ways without deviating from the inventive concept. For example, the electrical connection can be checked by a suitable test device before or after the formation of the protective layer 22. Likewise, the component assembly 25 can be subjected to temperature changes before or after the formation of the protective layer 22, for example, in order to thermomechanically stress the connection between the two connection areas 3, 11, thus reducing the probability of subsequent interruptions.

Claims

[1] Method for electrically contacting a component (1), wherein the component (1) is arranged on a circuit carrier (10) having a first connection area (11), wherein the first connection area (11) is connected to a second connection area (3) of the component (1) by means of an electrically conductive layer (21), wherein the electrically conductive layer (21) is applied by jet injection, and wherein the component (1) is fixed to the circuit carrier (10) by means of a curable fixing layer (16) in the form of an electrically non-conductive adhesive, characterized by, that the adhesive is applied to the circuit carrier (10) in such a way that the height of the adhesive is greatest in the middle of the oppositely arranged first connection areas (11) and decreases towards the first connection areas (11) and is lowest there, and that after the component (1) is placed on the adhesive the adhesive extends to a top surface (2) of the component (1) at its lateral edge areas and a continuous, non-stepped transition area (19) is created between the connection areas (3, 11). [2] Method according to claim 1, characterized by , that in a first step the component (1) is attached to the circuit carrier (10), and that in a second step the electrically conductive layer (21) is applied. [3] Method according to claim 1 or 2, characterized by , that an aerosol or a conductive adhesive is used as the electrically conductive layer (21). [4] Method according to any one of claims 1 to 3, characterized by , that after the application of the electrically conductive layer (21) it is cured, in particular by a heat treatment. [5] Method according to any one of claims 1 to 4, characterized by , that the electrically conductive layer (21) completely covers the two connection areas (3, 11) and does not extend beyond the connection areas (3, 11). [6] Component assembly (25) produced according to a method according to any one of claims 1 to 5. [7] Component composite according to claim 6, characterized by , that the area of ​​the component (1), the electrically conductive layer (21) and the two connection areas (3, 11) on the circuit carrier (10) is covered by a protective layer (22). [8] Component assembly according to one of claims 6 or 7, characterized by , that the component (1) is an IC or an ASIC.

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