Title of Invention

POWER SEMICONDUCTOR MODULE HAVING A SUBSTRATE AND A PRESSURE DEVICE

Abstract

The invention presents a power semiconductor module having a substrate/ having a housing and having a pressure device, the substrate having an insulating material body and structured conductor tracks which are arranged thereon and have load and auxiliary potentials, and the substrate having recesses in the region of the structured conductor tracks in at least two regions which are not covered by power semiconductor components. Furthermore, the pressure device has latching lugs, which are assigned to the recesses and are arranged in the latter in a form-fitting and/or frictional manner, at at least two points on its side which faces the substrate.

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 POWER SEMICONDUCTOR MODULE HAVING A SUBSTRATE AND A PRESSURE DEVICE 2. APPLICANT(S) a) Name : SEMIKRON ELEKTRONIK GMBH & CO. KG b) Nationality : GERMAN Company c) Address : SIGMUNDSTRASSE 200, 90431 NUERNBERG, GERMANY 3. PREAMBLE TO THE DESCRIPTION 10 N0V2008 The following specification particularly describes the invention and the manner in which it is to be performed : - The invention describes a compact pressure-contact-connected power semiconductor module without a base plate and having a frame-like insulating housing, having at least one substrate and having a pressure device. Power semiconductor modules, as are known, by way of example, from DE 197 19 703 Al, form a starting point of the invention. According to the prior art, such power semiconductor modules comprise a housing having at least one electrically insulating substrate which is arranged in the latter and is preferably intended to be directly mounted on a cooling component. The substrate, for its part, comprises an insulating material body having a plurality of structured metal connecting tracks, which are situated thereon and are insulated from one another, and having power semiconductor components which are situated thereon and are connected to these connecting tracks in a circuit-compliant manner. Furthermore, the known power semiconductor modules have connection elements for external load and auxiliary connections as well as connecting elements which are arranged in the interior. Pressure-contact-connected power semiconductor modules, as are disclosed in DE 199 03 875 Al or DE 101 27 947 CI, are likewise known. In the document mentioned first, the power semiconductor module has a pressure device comprising a stable pressure element for introducing pressure, said element having an advantageous ratio of weight and stability and, for this purpose, being in the form of a shaped plastic body with an internal metal core and also having electrically insulating bushings. Furthermore, the pressure device has an elastic cushion element for storing pressure and a bridge element for introducing pressure into separate regions of the substrate surface. In this case, the elastic cushion element is used to maintain constant pressure conditions under different thermal loads and over the entire life cycle of the power semiconductor module. The bridge element is preferably in the form of a 2 shaped plastic body having an area which faces the cushion element and from which a multiplicity of pressure fingers start in the direction of the substrate surface. Such a pressure device is preferably used to push the substrate onto a cooling component and hence to reliably produce permanent heat transfer between the substrate and the cooling component. DE 101 27 947 CI discloses a power semiconductor module, the load connection elements being designed in such a manner that sections of them run very close to one another at right angles to the substrate surface and they have internal contact devices which start therefrom, make electrical contact with the conductor tracks and simultaneously exert pressure on the substrate and thus preferably make thermal contact between the latter and a cooling component. In this case, the pressure is introduced, by way of example, using the abovementioned means according to the prior art. The disadvantage of power semiconductor modules which are formed in this manner without a base plate is that, during the pressure-introducing contact-connection of the internal contact devices to the conductor tracks of the substrate, the electrically insulating substrate is not protected from being rotated with respect to the frame-like housing in the mounting process as a result of the lack of a base plate. The action of force caused by the process of rotating the substrate with respect to the housing possibly results in damage to the substrate during mounting and thus results in a loss of performance right through to destruction of the power semiconductor module. Another disadvantage of such power semiconductor modules having spring contact elements as the load and auxiliary connection elements is that the internal contact device of these spring contact elements laterally slides off the structured conductor track as a result of the introduction of pressure and gives rise to a loss of contact 3 which may result in reduced performance of the power semiconductor module and, in the extreme case, to the total failure of the latter. The invention is based on the object of presenting a power semiconductor module having a pressure device and a substrate, the substrate being secured against rotation in the mounting process and the power semiconductor module being open to simple and cost-effective production. According to the invention, the object is achieved by means of the measures of the features of Claim 1. Preferred embodiments are described in the subclaims. The inventive concept is based on the requirements for a power semiconductor module having a substrate having at least one power semiconductor component, which is to be arranged and connected in a circuit-compliant manner, and having a housing having a pressure device and having load connection elements and auxiliary connection elements which lead to the outside. The substrate has an insulating material body, structured conductor tracks with a load potential being arranged on one main area of the body which faces the interior of the power semiconductor module. The substrate also has structured conductor tracks with an auxiliary potential for driving the power semiconductor components. The pressure device comprises a pressure-introducing pressure element, which preferably simultaneously forms the cover of the housing, and also preferably a bridge element for introducing pressure into the conductor tracks which are arranged on the substrate, which bridge element has channel-like recesses for leading through load connection elements and also preferably a plurality of pressure fingers in the direction of the substrate surface. The pressure device also preferably has an elastic cushion element for storing pressure and for maintaining constant pressure conditions. By way of example, the pressure-introducing element and the bridge element may also be integral without a cushion element. By way of example, 4 the bridge element may likewise be integrally formed with the frame-like housing of the power semiconductor module. The power semiconductor module also has load connection elements each in the form of shaped metal bodies having external and internal contact devices. The respective external contact devices of the individual load connection elements are preferably arranged parallel to the substrate surface and at a distance from the latter. The internal contact devices which start from the external contact devices preferably extend at right angles to the substrate surface through channel-like recesses in the bridge element and form the contacts of the load connections there in a circuit-compliant manner. As a further preferred possible refinement, the load and auxiliary connections are arranged in the form of electrically conductive spring contact elements. Recesses are preferably situated on the substrate in the region of the structured conductor tracks in at least two regions which are not covered by a power semiconductor component, and latching lugs which are accordingly assigned to the recesses are correspondingly situated at at least two points on that side of the pressure device, preferably a pressure finger of the bridge element, which faces the substrate. This necessitates the maximum area of a recess and the correspondingly assigned latching lug as a result of the maximum area of that side of a pressure finger which faces the substrate. In this case, the depth of a recess, and accordingly the height of a latching lug assigned to the recess, is at least 20% of the depth of the conductor track arranged on the substrate. Furthermore, the maximum depth of a latching lug which is assigned to the recess is restricted to 100% of the depth of the entire substrate. In this case, it is advantageous for the frictional connection between the contact devices and the substrate to simultaneously enable the form-fitting and/or frictional connection between the at least two recesses and the at least two latching lugs 5 accordingly assigned to the latter without further effort using the pressure device, as a result of which rotation of the substrate with respect to the housing is prevented according to the inventive concept. It is also advantageous that the recesses can be produced without further effort in the process of structuring the conductor tracks. In a corresponding manner, the latching lugs accordingly assigned to the recesses can be produced without further effort in the process of producing the bridge element which is preferably in the form of a plastic body. It is also advantageous that lateral sliding of the internal contact devices of the spring contact elements can be avoided if the internal contact device has a latching lug applied to its side facing the substrate and an accordingly assigned recess is arranged on the substrate. Particularly preferred developments of this arrangement are mentioned in the respective description of the exemplary embodiments. The inventive solution is also explained in more detail using the exemplary embodiments in Figs. 1 to 6. Fig. 1 shows a simplified illustration of a power semiconductor module according to the invention. Fig. 2 shows a side view of an enlarged detail of a first refinement of the power semiconductor module according to the invention. Fig. 3 shows a side view of an enlarged detail of a further refinement of the power semiconductor module according to the invention. Fig. 4 shows a plan view of an enlarged detail of a further refinement of the power semiconductor module according to the invention. 6 Fig. 5 shows a simplified illustration of a power semiconductor module according to the invention having a housing and shows an enlarged detail of a section according to the invention. Fig. 6 shows a further refinement of a power semiconductor module according to the invention. Fig. 1 shows a simplified illustration of a power semiconductor module without a base plate and having a substrate (1) having an insulating material body (10) and having structured conductor tracks (2a, 2b) which are arranged on the substrate and having power semiconductor components (3a, 3b) which are arranged on the conductor tracks. Furthermore, the power semiconductor module has a pressure device (4) having a pressure-introducing element (40) and a bridge element (42). Furthermore, the pressure device additionally has a cushion element (44) for storing pressure and for maintaining constant pressure conditions. In this case, the bridge element (42) preferably comprises a plastic body having a plurality of pressure fingers (420, 422, 424) which face the substrate. Furthermore, the power semiconductor module has a housing (9) (diagrammatically illustrated in this case using dotted lines). The conductor tracks (2a, 2b) arranged on the substrate (1) have load and auxiliary potentials which are used to electrically contact-connect the load connections (50, 52, 54) and auxiliary connections (60, 62) which lead to the outside. In this case, the arranged conductor tracks (2a, 2b) and load and auxiliary connections can be electrically contact-connected by means of internal contact devices (500, 520, 540), sections of which are routed at right angles to the substrate surface through channel¬like recesses in the bridge element. The at least two recesses (7a-d) according to the invention are situated in at least two regions, which are not covered by semiconductor components, on the structured 7 conductor tracks of the substrate. By way of example/ some recesses are cylindrical and others are dome-shaped, frustoconical or cross-shaped (not illustrated in cross section such that they can be distinguished here). Furthermore, the depth of some recesses (7a, 7c, 7d) is 50% of the thickness of the arranged structured conductor track and the depth of other recesses (7b) is 70% of the thickness of the entire substrate. The at least two latching lugs (8a-d) according to the invention are situated on those sides of at least one pressure finger which face the substrate and are accordingly assigned to the recesses (7a-d) according to the invention. Fig. 2 shows a side view of an enlarged detail of a first refinement of the power semiconductor module according to the invention having a substrate (1) having an insulating material body (10) and having structured conductor tracks (2a, 2b) which are arranged on the substrate and having a recess (7a) according to the invention which is frustoconical in this case and has a depth of 70% of the entire thickness of the substrate. Also illustrated is a pressure finger (420) of the bridge element (42), which pressure finger extends at right angles in the difection of the substrate surface, and a latching lug (8a) which is accordingly assigned to the recess (7a) and produces a frictional connection to the recess in the substrate (fig- 2, right-hand side of the image) in conjunction with a pressure device (4, not illustrated here). In this case, the depth of the latching lug does not reach 100% of the depth of the recess but rather leaves a residual volume of the recess free (70). Fig. 3 shows a side view of an enlarged detail of a further refinement of the power semiconductor module according to the invention having a substrate (1) having an insulating material body (10) and having conductor tracks (2a, 2b) which are arranged on the substrate. In this case, the bridge elernent (42) has two latching lugs (8c). Two recesses (7d) in which the conductor tracks (2a, 2b) have accordingly been interrupted are formed on the substrate. The latching lugs (8c) are arranged in these 8 two recesses (7d) in such a manner that that part of the conductor track (2c) which remains between the two latching lugs (8c) enters a form-fitting or frictional connection (fig. 3, right-hand side of the image) with the two latching lugs (8c) even though the recesses (7d) themselves are wider than the latching lugs (8c) assigned to them. Fig. 4 shows a plan view of a detail of a substrate (1) of a power semiconductor module (1) according to the invention, having structured conductor tracks (2a, 2b), which are arranged on the substrate, and having an insulating material body (10) which becomes visible in plan view only in the region of the conductor track structuring. Also illustrated is an exemplary semiconductor component (3a) and two recesses (7a, 7b) according to the invention which are arranged in two regions, which are not covered by the semiconductor component, on, by way of example, one of the structured conductor tracks (2a) arranged on the substrate, the recesses according to the invention being cylindrical by way of example here. Fig. 5 shows a simplified illustration of a further refinement of a power semiconductor module according to the invention having a frame-like housing (9), having a substrate (1) having an insulating material body (10) and having structured conductor tracks (2a, 2b) which are arranged on the substrate and having power semiconductor components (3a, 3b) which are arranged on the conductor tracks. Furthermore, the load connection elements (50, 52, 54) are in the form of shaped metal bodies which each have a strip-like section parallel to the substrate surface and form a stack, and the individual load connection elements are at a distance from one another by virtue of necessary insulation (15, 17). Required auxiliary connection elements are not illustrated in this sectional drawing for reasons of clarity. In this case, the pressure device (4) has a pressure-introducing element (40) and the load connections which introduce the pressure into the substrate. In this case, the frictional connection is produced directly using the internal contact devices of the 9 load connections on the structured conductor tracks (2a, 2b) of the substrate (1). The at least two recesses (7a, 7b) according to the invention and the latching lugs (8a, 8b) assigned to the latter are dome-shaped in this case, the assigned latching lugs being fitted to that side of the internal contact devices (500, 520, 540) of the load connections (50, 52, 54) which faces the conductor tracks. Fig. 6 shows a simplified illustration of a further refinement of a power semiconductor module according to the invention having a substrate (1) having an insulating material body (10) and having structured conductor tracks (2a, 2b) which are arranged on the substrate and having power semiconductor components (3a, 3b) which are arranged on the conductor tracks. In this case, the pressure device (4) is in the form of a pressure-introducing element (40) and a bridge element (42), the bridge element being integral with the frame-like housing (9) of the power semiconductor module, and the pressure device dispensing with a cushion element on account of the flexibility of the spring contact elements. Furthermore, the load connection elements (50, 52) and auxiliary connection elements (60) are in the form of spring contact elements, the electrical contact-connection to the structured conductor tracks being formed by internal contact devices (54), sections of which are routed at right angles to the substrate surface through channel-like recesses in the bridge element (42). The at least two recesses (7a, 7b) according to the invention and the latching lugs (8a, 8b) assigned to the latter are cylindrical and have a depth of 30% of the thickness of the entire substrate (1). Alternatively or additionally, latching lugs (80a, 80b) are fitted to the internal contact-connections between the spring contact elements (50) and the structured conductor tracks, which latching lugs in turn accordingly enter a form-fitting and frictional connection with the recesses (70a, 70b) assigned to them on the associated conductor track. In the design of the springs which is illustrated here, these latching lugs (80a, 80b) may be in the form of extensions of the spring body. In the case of helical springs which are not illustrated and are formed, by way of example, from a 10 metal wire, the internal contact-connection, which is in the form of a straight wire section, may itself form the latching lug. CLAIM: 1. Power semiconductor module having at least one substrate (1) having at least one semiconductor component (3a, 3b), having a housing (9), having a pressure device (4) and having load connection elements (50, 52, 54) and auxiliary connection elements (6, 60,62) which lead to the outside, the substrate (1) having an insulating material body (10), and conductor tracks (2a, 2b) with load and auxiliary potentials being arranged on the first main area of said body which faces the interior of the power semiconductor module, that main area of the substrate which faces the interior of the power semiconductor module having at least two recesses (7a, 7b, 7c, 7d) in the region of the arranged conductor tracks (2a, 2b) in at least two regions which are not covered by power semiconductor components, and the pressure device (4) having latching lugs (8a, 8b, 8c, 8d), which are assigned to the recesses and are arranged in the latter in a form-fitting and/or frictional manner, at at least two points on its side which faces the substrate. 2. Power semiconductor module according to Claim 1, the pressure device having an elastic cushion element (44) which is arranged between a pressure-introducing pressure element (40) and a bridge element (42). 3. Power semiconductor module according to Claim 2, the bridge element (42) being in the form of a plastic body having a flat partial body which faces the cushion element (44) and from which a plurality of pressure fingers (420,422, 424) start in the direction of the substrate surface. 12 4. Power semiconductor module according to Claim 1, the latching lugs being frustoconical or dome-shaped or cylindrical or cross-shaped or platform-shaped, and the recesses (8a, 8b, 8c) which are assigned to them being shaped in a corresponding manner in order to accommodate them. 5. Power semiconductor module according to Claim 2, sections of the load connection elements (50, 52, 54) being arranged at right angles to the substrate surface through channel-like recesses in the bridge element (42) and having, on the side facing the substrate (1), contact devices (500, 520, 540) for electrical contact-connection to the conductor tracks (2a, 2b) arranged on the substrate. 6. Power semiconductor module according to Claim 2, the housing (9) laterally surrounding the bridge element (42) and the at least one substrate (1) in a frame-like manner. 7. Power semiconductor module according to Claim 1, the pressure-introducing pressure element (40) forming the upper termination of the power semiconductor module. 8. Power semiconductor module according to Claim 1, the minimum depth of the recesses (7a, b, c, d) being 20% of the thickness of the substrate (1) and the maximum depth of the recesses being 100% of the thickness of the substrate. 13 9. Power semiconductor module according to Claim 1, the minimum depth of the latching lugs (8a, b, c, d) which are assigned to the recesses being 20% of the thickness of the substrate (1) and the maximum depth of the latching lugs which are assigned to the recesses being 100% of the thickness of the substrate. 10. Power semiconductor module according to Claim 1, at least one load connection element (50, 52, 54) itself forming part of the pressure device (4). Dated this 10th day of November, 2008 HIRALCH ANDRAKANT JOSHI AGENT FOR SEMIKRON ELEKTRONIK GMBH & CO. KG 14

Documents:

2379-mum-2008-abstract.doc

2379-mum-2008-abstract.pdf

2379-MUM-2008-CANCELLED PAGE(26-7-2013).pdf

2379-MUM-2008-CANCELLED PAGES(2-9-2013).pdf

2379-MUM-2008-CLAIMS(AMENDED)-(18-3-2014).pdf

2379-MUM-2008-CLAIMS(AMENDED)-(2-9-2013).pdf

2379-MUM-2008-CLAIMS(MARKED COPY)-(18-3-2014).pdf

2379-MUM-2008-CLAIMS(MARKED COPY)-(2-9-2013).pdf

2379-mum-2008-claims.doc

2379-mum-2008-claims.pdf

2379-MUM-2008-CORRESPONDENCE(19-11-2008).pdf

2379-MUM-2008-CORRESPONDENCE(26-7-2013).pdf

2379-MUM-2008-CORRESPONDENCE(28-11-2008).pdf

2379-MUM-2008-CORRESPONDENCE(31-12-2012).pdf

2379-MUM-2008-CORRESPONDENCE(5-3-2010).pdf

2379-MUM-2008-CORRESPONDENCE(9-1-2009).pdf

2379-mum-2008-correspondence.pdf

2379-mum-2008-description(complete).doc

2379-mum-2008-description(complete).pdf

2379-mum-2008-drawing.pdf

2379-MUM-2008-ENGLISH TRANSLATION OF PRIORITY DOCUMENT(28-11-2008).pdf

2379-mum-2008-english translation.pdf

2379-MUM-2008-FORM 1(9-1-2009).pdf

2379-mum-2008-form 1.pdf

2379-mum-2008-form 18.pdf

2379-mum-2008-form 2(title page).pdf

2379-mum-2008-form 2.doc

2379-mum-2008-form 2.pdf

2379-MUM-2008-FORM 26(18-3-2014).pdf

2379-MUM-2008-FORM 3(2-9-2013).pdf

2379-MUM-2008-FORM 3(26-7-2013).pdf

2379-mum-2008-form 3.pdf

2379-MUM-2008-FORM 5(2-9-2013).pdf

2379-mum-2008-form 5.pdf

2379-MUM-2008-GENERAL POWER OF ATTORNEY(2-9-2013).pdf

2379-mum-2008-general power of attorney.pdf

2379-MUM-2008-OTHER DOCUMENT(2-9-2013).pdf

2379-MUM-2008-PETITION UNDER RULE-137(26-7-2013).pdf

2379-MUM-2008-PRIORITY DOCUMENT(19-11-2008).pdf

2379-MUM-2008-REPLY TO EXAMINATION REPORT(2-9-2013).pdf

2379-MUM-2008-REPLY TO HEARING(18-3-2014).pdf

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