Title of Invention

CONNECTING DEVICE FOR ELECTRONIC COMPONENTS

Abstract

The invention describes a connecting device for the electrically conductive connection of electronic components and a substrate. In this case, the connecting device is formed as a film composite composed of at least one insulating film and two electrically conductive films. Said film composite is formed as a layer construction of in each case a conductive film alternating with an insulating film, wherein at least one conductive film is structured and thus forms conductor tracks. Furthermore, at least one conductive film of a main area of the film composite comprises a first metal and has at least one film section having a layer of a second metal that is thinner in comparison with the thickness of said film.

Full Text

FORM 2 THE PATENT ACT 1970 (39 Of 1970) The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10, and rule 13) 1. TITLE OF INVENTION CONNECTING DEVICE FOR ELECTRONIC COMPONENTS APPLICANT(S) a) Name b) Nationality c) Address SEMIKRON ELEKTRONIK GMBH & CO. KG GERMAN Company POSTFACH 820251, 90253 NURNBERG, GERMANY PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed : - Description The invention describes a connecting device for the electrically conductive connection of electronic components and at least one substrate, wherein the connecting device is formed as a film composite. A multiplicity of connecting devices for electronic components are known. In the case of packaged components, by way of example, metallic connecting device and the connection thereof to substrates by means of soldering technology are known, where substrates in this case are also to be understood to mean a type of printed circuit boards. The wire bonding connection is widespread as a connecting device in the case of unpackaged components. Positively locking connections are furthermore known, as so-called pressure contact-connection, in the area of power semiconductor modules. Likewise from power semiconductor modules, pressure-contact-connected flexible printed circuit boards are known as connecting devices. DE 102 21 970 Al discloses a power semiconductor module comprising a connecting device of this type, but leaves open the exact configuration thereof. DE 103 55 925 Al discloses a connecting device for power semiconductor components comprising a film composite of a first and a second electrically conductive film with an insulating interlayer. The power semiconductor components are permanently securely electrically connected to the first conductive layer by means of ultrasonic welding. In that case, the module-internal circuitry-conforming connection of the power semiconductor components to conductor tracks of a substrate is formed by means of metallic contact elements whose thickness is adapted to that of the power semiconductor components. Said contact elements are connected to the connecting device by means of ultrasonic welding in the same way as the power semiconductor components. 2 In that case, the conductive film for the ultrasonic welding connection to power semiconductor component and contact elements comprises aluminium with embossing bumps since aluminium forms an excellent welding connection with the metallization of the power semiconductor component, said metallization likewise comprising a final layer of aluminium. What is disadvantageous in that case is that soldering connections with said aluminium layer are not possible or are possible only to a very limited extent. A configuration of the corresponding layer by means of copper, which has a higher specific conductivity and is solderable, is not disclosed here since this layer is not suitable for a welding connection to the power semiconductor components. The invention is based on the object of presenting a connecting device for electronic components, such as, by way of example, unpackaged power semiconductor components and packaged or unpackaged integrated circuits, which is amenable both to a welding connection and to a soldering connection and connects a plurality of components in a simple, rapidly producible and flexible manner. The object is achieved according to the invention by means of the measures of the features of Claim 1. Preferred embodiments are described in the subclaims. The inventive concept is based on, but not restricted to, the requirements of an intelligent power semiconductor module having a plurality of components that are to be arranged differently and connected in circuitry-conforming fashion. In a power semiconductor module of this type, unpackaged power semiconductor component are to be connected to one another and/ or to conductor tracks of a substrate on which they are arranged. Furthermore, control and auxiliary connections have to be connected to driver components and further electronic components which are arranged either in packaged fashion or in unpackaged fashion in the power semiconductor module. Furthermore, by way of example, sensors for temperature and/or current measurement are to be connected to assigned evaluation units. The 3 external connections of the load connections and of all the required control and auxiliary connections of the power semiconductor components as well as of the driver components are likewise to be connected. The connecting device according to the invention is configured as a film composite composed of at least one insulating film and two electrically conductive films. Said film composite has a layer construction beginning with a conductive film and then alternately in each case an insulating film and a conductive film. At least one conductive film is inherently structured and thus forms conductor tracks that are electrically insulated from one another. At least one conductive film which comprises a first metallic material and which is arranged on a main area of the film composite has at least one film section, wherein a layer of a second metallic material is arranged on said film section. According to the invention, the layer thickness of said layer composed of the second metallic material is thinner in comparison with the layer thickness of the film composed of the first metallic material. Particularly preferred developments of this connecting device are mentioned in the respective description of the exemplary embodiments. The inventive solution is additionally explained in more detail on the basis of the exemplary embodiments of Figures 1 to 3. Figure 1 shows in cross section a first connecting device according to the invention in an arrangement with a substrate and components. Figure 2 shows a second connecting device according to the invention in a plan view of the first main area. 4 Figure 3 shows a second connecting device according to the invention in an arrangement with an unpackaged component in a plan view of the second main area. Figure 1 shows a first connecting device (1) according to the invention in the arrangement with a substrate (2) and components (3 a/b, 4, 5) in cross section. The substrate (2) has conductor track (22) that are electrically insulated from one another on its side facing the connecting device (1). Substrates (2) of this type are formed for use in power semiconductor modules preferably as so-called DCB (direct copper bonding) substrates with metallic conductor tracks (22) composed of copper on a ceramic carrier (20). Any other substrates that form conductor track that are electrically insulated from one another are likewise suitable, in which case said conductor tracks need not be formed over the whole area below the components arranged on the substrate, as illustrated. However, this formation is preferred if heat has to be dissipated from the component. The components (3 a/b) arranged on the conductor tracks (22) of the substrate (2) are in this case a power diode (3b) and power transistor (3a), where this does not mean any restriction to these components. These power semiconductor components (3 a/b) have at least one contact area (32, 34,36) on their side facing the connecting device (1). This is the anode (36) in the case of the power diode (3b), and the emitter (32) and also the base (34) in the case of the power transistor (3a). In accordance with the prior art, the contact areas of the power semiconductor components (3 a/b) are formed as an aluminium layer. In a first configuration, the connecting device (1) comprises a first metallic film (10), here aluminium having a layer thickness of between 50 and 400 urn, an adjoining plastic film (14) having a layer thickness of between 10 and 80 urn, and a second metallic film (12), here copper having a layer thickness of between 20 and 100 um, the first film having at least twice the thickness of the second film. 5 For the electrically conductive connection of the first metallic film (10) to the contact areas (32,34,36) of the power semiconductor components (3 a/b), the film composite (1) has first embossing bumps (16a). Said embossing bumps (16a) are connected to the assigned contact areas (32,34,36) by means of an ultrasonic welding method. For the electrically conductive connection of the first metallic film (10) to conductor tracks (22) of the substrate (2), the film composite (1) has second embossing bumps (16b) formed in deeper fashion. In the region of said second embossing bumps (16b), a layer composed of copper having a preferred thickness of between 1 and 20 urn is deposited on the aluminium film (10). In this case, it is preferred for this to be carried out by means of a galvanic method or by means of cold gas spraying. The copper surface of said second embossing bumps (16b) is connected to the copper conductor track (22) of the substrate (2) by means of soldering technology. The plastic film (14) of the connecting device (1) has cutouts for plated-through holes (18) between the first (10) and the second (12) conductive layer. Potentials of the first layer are thereby applied to the second layer. This is illustrated by way of example for the gate potential of the power transistor (3a). Two integrated circuits (4, 5) are arranged here by way of example on the second metallic film (12). It may be preferred here to arrange further components such as individual resistors, capacitors, coils or else sensors. In further configurations, components of this type may also be arranged on conductor tracks (22) of the substrate (2) and connected in circuitry-conforming fashion. The illustration shows a first integrated circuit (4), here in the form of an SMD component with contact devices (40) for connection to assigned conductor track of the second film (12) by means of soldering technology. A second integrated circuit (5) is illustrated here as an unpackaged component and is connected to the second conductive layer (12) by adhesive bonding technology. The electrical connection is formed as a thin wire bonding connection (52) of individual contact areas (50) of the component (5) to assigned conductor tracks of the second layer (12). 6 It may be preferred to arrange a second metallic layer in the configuration of a gold layer on the sections of said conductor tracks which are connected to the bonding wires (52). External connection, by way of example screw connections, of said connecting device (1) may be formed as round cutouts of the entire film composite. In this case, it is preferred to arrange a second metallic layer concentrically around said cutouts on at least one conductive film layer of a main area. In this case, it is preferred for said layer to have at least a thickness of 100 um and to be deposited by means of cold gas spraying. In a second configuration, which is not explicitly illustrated, the connecting device (1) comprises a first metallic film, here copper having a layer thickness of between 30 and 300 urn, an adjoining plastic film having a layer thickness of between 10 and 80 urn and a second metallic film, likewise composed of copper having a layer thickness of between 30 and 300 urn. In this configuration, the sections of the first layer which serve for welding connection to the contact areas of the power semiconductor components are formed with a second layer composed of aluminium. It is only by this means that it is possible to achieve a permanently durable connection. The embossing bumps for the connection to the conductor tracks of the substrate by means of soldering technology does not require a second metallic layer in this case. The three-layered construction described here is likewise presupposed in Figures 2 and 3. Further configurations of the connecting device according to the invention have by way of example metallic layers composed of in each case identical metals having an identical layer thickness of the two layers. According to the invention, it may likewise be advantageous to form a layer sequence of 5 layers, wherein here the 7 central metallic layer is preferably formed in particularly thin fashion, as a screening plane, and is at a defined potential during operation. Figure 2 shows the film composite of a second connecting device (1) according to the invention in a plan view of the first main area of said connecting device. The illustration shows an insulating layer (14) in the configuration of a plastic film and, in a first formation of the film composite, a first conductive layer (10) composed of aluminium. This aluminium layer (10) is inherently structured and, in this excerpt from the film composite, forms three conductor tracks that are electrically insulated from one another. Each of these conductor track (10) has two groups of embossing bumps (16 a/b) for ultrasonic welding connection of unpackaged semiconductor components, here of power diodes, or for the soldering connection to conductor tracks of a substrate. Alternative embodiments of this structuring are suitable for a multiplicity of different unpackaged components to be connected, not only of power semiconductor components. In the first configuration, the first group of embossing bumps (16a) is suitable for the spot welding connection of components to contact areas which are preferably likewise formed from aluminium. In the section of the second group of embossing bumps (16b), the aluminium layer is arranged with a thinner layer (102) of copper deposited by electrodeposition or by means of cold gas spraying. This copper layer (102) is particularly suitable for a soldering connection to a conductor track of the substrate. In a second embodiment (not illustrated), the second conductive layer comprises copper. This is particularly preferred since copper has a high thermal conductivity for transporting away heat loss from the components and also a low resistivity for a high current-carrying capacity. In this case, it is necessary to form the group of embossing bumps for the spot welding connection to components with a second layer composed of aluminium in order to provide a suitable surface for the welding connection. 8 Figure 3 shows a second connecting device (1) according to the invention in an arrangement with an unpackaged component (1) arranged thereon, in a plan view of the second main area. The illustration shows em insulating layer (14) in the configuration of a plastic film and a second conductive layer (12) composed of copper. This copper layer (12) is inherently more finely structured in comparison with the first metallic layer (10, cf. Figure 2) and in this excerpt forms an area for the adhesive-bonding connection of the component (5), here a driver circuit for driving power semiconductor components. The copper layer furthermore forms a multiplicity of conductor tracks (12) connecting said driver circuit. Said conductor tracks are in turn electrically insulated from one another and have further contact areas for further components, as shown here by way of example in the form of a capacitor (6). Said conductor tracks furthermore have sections which are provided with a further metallic layer (122), here in the configuration of a gold layer having a thickness of between 0.5 and 5 um. These sections with a gold coating are the preferred contact areas for the thin wire bonding connection (52) of the contact areas (50) of the driver circuit (5) to the conductor tracks (12). A plated-through hole (18) to the first conductive layer of the film composite is likewise illustrated. 9 WE CLAIM 1. Connecting device (1) for the electrically conductive connection of electronic components (3 a/b, 4, 5, 6) and at least one substrate (2), wherein the connecting device (1) is formed as a film composite composed of at least one insulating film (14) and two electrically conductive films (10, 12), said film composite is arranged in a layer construction of in each case a conductive film alternating with an insulating film and at least one conductive film is structured and thus forms conductor tracks, wherein at least one conductive film (10, 12) of a main area of the film composite comprises a first metal and has at least one film section having a layer (102, 122) of a second metal that is thinner in comparison with the thickness of said film. 2. Connecting device according to Claim 1, wherein at least one insulating film (14) has at least one cutout for the electrically conductive connection (18) of adjacent conductive films. 3. Connecting device according to Claim 1, wherein the film composite (1) has at least one embossing bump (16 a/b). 4. Connecting device according to Claim 3, wherein the embossing bump (16 a/b) is arranged in a film section having a layer (102,122) of a second metal. 5. Connecting device according to Qaim 4 or 5, wherein an unpackaged power semiconductor component (3 a/b) is arranged and electrically conductively connected in circuitry-conforming fashion by means of a spot welding connection to embossing bumps (16a) of the film composite on the first main area thereof. 10 6. Connecting device according to Claim 4 or 5, wherein a conductor track (22) of a substrate (2) is electrically conductively connected in circuitry-conforming fashion by means of a soldering connections to embossing bumps (16b) of the film composite (1). 7. Connecting device according to Claim 1, wherein packaged (4) or unpackaged (5) components are arranged on the second main area of the film composite (1) by means of soldering technology or adhesive bonding technology. 8. Connecting device according to Claim 7, wherein unpackaged components (5) are electrically conductively connected in circuitry-conforming fashion by means of thin wire bonding connection (52) to conductor tracks (12) of the second main area of the film composite (1). 9. Connecting device according to Claim 1, wherein the layer (102, 122) composed of the second metal is deposited by means of cold gas spraying. 10. Connecting device according to Claim 1, wherein the layer (102, 122) composed of the second metal is deposited by electrodeposition. HIRAL CHANtfRAKANT JOSHI AGEISTPFOR SEMIKRON ELEKTRONIK GMBH & CO. KG 11 Dated this 19th day of February, 2007 Abstract The invention describes a connecting device for the electrically conductive connection of electronic components and a substrate. In this case, the connecting device is formed as a film composite composed of at least one insulating film and two electrically conductive films. Said film composite is formed as a layer construction of in each case a conductive film alternating with an insulating film, wherein at least one conductive film is structured and thus forms conductor tracks. Furthermore, at least one conductive film of a main area of the film composite comprises a first metal and has at least one film section having a layer of a second metal that is thinner in comparison with the thickness of said film. To, The Controller of Patents, The Patent Office, Mumbai 12 (Figure 1)

Documents:

307-mum-2007-abstract(granted)-(16-8-2010).pdf

307-mum-2007-abstract.doc

307-mum-2007-abstract.pdf

307-MUM-2007-CANCELLED PAGES(16-6-2010).pdf

307-MUM-2007-CLAIMS(AMENDED)-(16-6-2010).pdf

307-mum-2007-claims(granted)-(16-8-2010).pdf

307-mum-2007-claims.doc

307-mum-2007-claims.pdf

307-mum-2007-correspondance-received.pdf

307-MUM-2007-CORRESPONDENCE(16-6-2010).pdf

307-mum-2007-correspondence(30-3-2007).pdf

307-mum-2007-correspondence(ipo)-(16-6-2009).pdf

307-mum-2007-correspondence(ipo)-(18-6-2010).pdf

307-mum-2007-description (complete).pdf

307-mum-2007-description(granted)-(16-8-2010).pdf

307-mum-2007-drawing(granted)-(16-8-2010).pdf

307-mum-2007-drawings.pdf

307-mum-2007-form 1(30-3-2007).pdf

307-mum-2007-form 2(granted)-(16-8-2010).pdf

307-mum-2007-form 2(title page)-(complete)-(19-2-2007).pdf

307-mum-2007-form 2(title page)-(granted)-(16-8-2010).pdf

307-MUM-2007-FORM 3(16-6-2010).pdf

307-mum-2007-form 3(19-2-2007).pdf

307-MUM-2007-FORM 5(16-6-2010).pdf

307-mum-2007-form-1.pdf

307-mum-2007-form-18.pdf

307-mum-2007-form-2.doc

307-mum-2007-form-2.pdf

307-mum-2007-form-26.pdf

307-mum-2007-form-3.pdf

307-mum-2007-form-5.pdf

307-MUM-2007-OTHER DOCUMENT(16-6-2010).pdf

307-MUM-2007-PETITION UNDER RULE 137(16-6-2010).pdf

307-MUM-2007-REPLY TO EXAMINATION REPORT(16-6-2010).pdf

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