Title of Invention

POWER SEMICONDUCTOR MODULE WITH CONNECTION ELEMENTS ELECTRICALLY INSULATED FROM ONE ANOTHER

Abstract The invention describes a power semiconductor module, for arrangement on a cooling component, having a substrate, at least two power semiconductor components arranged thereon, a housing and outwardly routed load and control connection elements. In this context, the substrate has an insulator body and the latter"s first main area, facing the interior of the power semiconductor module, has interconnects at load potential arranged on it. The load connection elements are respectively in the form of a metal shaped body with outer contact devices, a strip-like section and with inner contact devices starting from said strip-like section. The inner contact devices extend from the strip-like section to the substrate and make circuit-compliant contact therewith. In addition, the load connection elements, with the exception of the regions of the outer and inner contact devices, are completely encased by an insulator and accordingly electrically insulated from one another.
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 WITH CONNECTION ELEMENTS ELECTRICALLY INSULATED FROM ONE ANOTHER

APPLICANT(S)
a) Name : SEMIKRON ELEKTRONIK GMBH & CO. KG
B) Nationality : GERMAN Company
c) Address : POSTFACH 82 0251,
90253 NURNBERG,
GERMANY

3. 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 power semiconductor module in pressure-contact form for arrangement on a cooling component. A starting point for the invention is formed by power semiconductor modules as are known by way of example from DE 197 19 703 Al.
On the basis of the prior art, such power semiconductor modules comprise a housing having at least one electrically insulating substrate arranged therein, preferably for direct assembly on a cooling component. The substrate for its part comprises an insulator body having a plurality of metal interconnects thereon which are insulated from one another, and power semiconductor components thereon which are circuit connected to these interconnects in circuit-compliant fashion. In addition, the known power semiconductor modules have connection elements for external load and auxiliary connections and also connecting elements arranged in the interior. These connecting elements for circuit-compliant connections in the interior of the power semiconductor module are usually in the form of wire bonding connections.
Similarly known are power semiconductor modules with pressure contact, as are known from DE 42 37 632 Al, DE 199 03 875 Al or DE 101 27 947 CI. In the case of the first document mentioned, the pressure device has a stable, preferably metal, pressure element for pressure setup, an elastic cushion element for pressure storage and a bridge element for introducing pressure to separate regions of the substrate surface. The bridge element is preferably in the form of a plastic shaped body with an area which faces the cushion element and from which there come a multiplicity of pressure fingers in the direction of the substrate surface.
A pressure device of this kind is used to push the substrate onto a cooling component and hence to reliably produce permanent heat transfer between the substrate and the cooling component. 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.
DE 199 03 875 Al develops the known pressure element such that it firstly has a particularly advantageous ratio of weight and stability and secondly has electrically insulated bushings. To this end, the pressure element is in the form of a plastic shaped body with an internal metal core. This metal core has recesses for passing through connection elements, preferably auxiliary connection elements in spring contact form. The plastic shaped body surrounds these recesses such that the auxiliary connection elements are electrically insulated from the metal core by means of the plastic shaped body.
Developed pressure elements are also known which have a multiplicity of pressure fingers on their surface facing the substrate. Preferably, the metal core in this context also has a preset sag. In the combination of both measures, a pressure element of this kind can provide the entire functionality of a pressure device as stated above.
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DE 101 57 947 CI discloses a power semiconductor module, where the load connection elements are in a form such that sections of them run very close to one another at right angles to the substrate surface and they have inner contact devices, contact feet, starting therefrom which make the electrical contact with the interconnects and simultaneously exert pressure on the substrate and hence make the thermal contact between the latter and a cooling component. In this case, the pressure is introduced using means based on the prior art.
The invention is based on the object of presenting a power semiconductor module in pressure contact form, where the inner insulation of the power semiconductor module is improved and the design of the pressure contact form is simplified.
The invention achieves the object by means of the measures in the features of Claim 1. Preferred embodiments are described in the subclaims.
The inventive concept is based on an arrangement of a power semiconductor module in pressure contact form on a cooling component, having at least one substrate, at least two power semiconductor components, for example bipolar transistors, arranged thereon, a housing and outwardly routed load and control connection elements. The substrate itself has an insulator body and the latter's first main area, facing the interior of the power semiconductor module, has interconnects at load potential. In addition, the substrate preferably also has at least one interconnect at control potential for actuating the power semiconductor components.
Furthermore, the power semiconductor module has load connection elements, respectively in the form of a metal shaped body with outer and inner contact devices and a strip-like section. The respective strip-like sections of the individual load connection elements are preferably arranged parallel to the substrate surface and at a distance therefrom. The inner contact devices which start from the strip-like section extend to the substrate, where they make the circuit-compliant contacts for the load connections. Preferably, they achieve this on the substrate by making contact with the interconnects at load potential, alternatively also directly with the power semiconductor components.
In line with the invention, the load connection elements (40, 42, 44) have a casing containing an insulator. With the exception of the regions of the outer and inner contact devices, the load connection elements are preferably completely encased by this insulator and at the same time therefore electrically insulated from one another. In addition, it is particularly preferred if the encased load connection elements form a stack which therefore represents a production unit.
The inventive solution is explained further with reference to the exemplary embodiments in Figures 1 to 3.
Figure 1 shows a section through a power semiconductor module based on the prior art.
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Figure 2 shows a section through a power semiconductor module based on the invention.
Figure 3 shows a three-dimensional illustration of a stack of load connection elements in a power semiconductor module based on the invention.
Figure 1 shows a section through a power semiconductor module (1) based on the prior art. This power semiconductor module (1) has a housing (3) with a frame-like housing part. In this case, the frame-like housing part surrounds the at least one substrate (5). This substrate in turn has an insulator body (52), preferably an insulating ceramic, such as aluminium oxide or aluminium nitrite.
On the first main area, facing the interior of the power semiconductor module (1), the substrate (5) has an inherently patterned metal lining. In this case, the individual sections of this metal lining, which is preferably in the form of a copper lining, form the interconnects (54) of the power semiconductor module (1). The second main area of the substrate (5) has an unpatterned copper lining (56) on the basis of the prior art.
The interconnects (54) of the substrate (5) have controllable and/or uncontrolled power semiconductor components (60) arranged on them, such as IGBTs (Insulated Gate Bipolar Transistors) with respective back-to-back connected freewheeling diodes, or MOSFETs. These are circuit connected to other interconnects (54) in circuit-compliant fashion, for example by means of wire bonding connections (62).
The load connection elements (40, 42, 44) for the various potentials which occur in the power semiconductor module are used for the external connection of the power-electronics circuit inside the power semiconductor module (1). To this end, the load connection elements (40, 42, 44) are in the form of metal shaped bodies which respectively have a strip-like section (402, 422, 442) in parallel with the substrate surface. In this case, these strip-like sections (402, 422, 442) form a stack, with the strip-like sections of the individual load connection elements (40, 42, 44) being spaced apart from one another exclusively by a requisite insulation (46), for example in the form of a plastic film. Such plastic films are respectively arranged between adjacent connection elements in order to ensure the electrical insulation of the different potentials of the connection elements. Requisite auxiliary connection elements have not been shown in this sectional drawing for reasons of clarity.
In addition, the power semiconductor module (1) has an intermediate layer, in the form of an insulator shaped body (30), between the stack of strip-like sections (402, 422, 442) of the load connection elements (40, 42, 44) and the substrate (5). In this refinement, this insulator shaped body (30) is arranged in the frame-like housing (3) using a snap-lock connection (90).
The insulator shaped body (30) for its part has recesses (32) for passing through inner contact connections, in this case contact feet (400, 420, 440), of the load connection elements (40, 42, 44). It is particularly preferred if these recesses (32) are in the form of guides for these contact feet (400, 42, 44), which improves the
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positioning of the load connection elements (40, 42, 44) relative to the substrate (5) or to its interconnects (54).
A pressure device (70) for thermally connecting the power semiconductor module (1) to a cooling component (2) and at the same time for electrically contact connecting the load connection elements (40, 42, 44) to the interconnects (54) of the substrate (5) is formed, by way of example, by a pressure element for the pressure setup and also by an elastic cushion element for pressure storage. The pressure is introduced to the stack of strip-like sections (402, 422, 442) of the load connection elements (40, 42, 44) via the cushion element and therefore exerts pressure on the contact feet (400, 420, 440). This causes these to be electrically conductively connected to interconnects (54) of the substrate (5).
Such pressure contact connections (70) have been found to provide particularly reliable contact over the life of power semiconductor modules (1). Another advantage for pressure contact connection is the recesses (32) in the insulator shaped body (30) being in the form of guides, since this means that the positioning of the contact feet (400, 420,440) is particularly accurate.
By way of example, the pressure element is in the form of a plastic shaped body with a suitable, internal metal core, in which case it is also possible to dispense with a cushion element which stores pressure. It is also preferred if the pressure element simultaneously forms the cover of the power semiconductor module (1).
Figure 2 shows a section through a power semiconductor module (1) based on the invention. In this exemplary refinement, the substrate (5), the housing (3) and the pressure device (70) are produced on the basis of the aforementioned prior art, and this means that the invention is not limited to this refinement, specifically to the refinement of the power semiconductor module in pressure contact form.
The form of the metal shaped bodies of the load connection elements (40, 42, 44) likewise corresponds to the prior art. In contrast thereto, the load connection elements (40, 42, 44) are developed, in line with the invention, such that they have a casing (408, 428, 448) containing an insulator. This casing encases the respective load connection element (40, 42, 44) more or less completely. The casing has parts of the contact devices (400, 420, 440), for example for the interconnects (54) of the substrate (5), cut out from it.
This form of the load connection elements (40, 42, 44) which is based on the invention means that it is naturally possible to dispense with the arrangement of plastic films between the load connection elements. This simplifies the design of the power semiconductor module (1) in a first step. A further simplification for this design is obtained if the load connection elements (40, 42, 44) form a stack (4) in the region of the strip-like sections (402, 422, 442). This can be done, by way of example, by bonding the individual load connection elements (40, 42,44) already encased with insulator (408, 428, 448). It may also be particularly preferred if a plurality of load connection elements (40,42,44) are encased with insulator in one step.
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Figure 3 shows a three-dimensional illustration of a stack (4) of load connection elements (40, 42, 44) in a power semiconductor module based on the invention. The figure shows load connection elements (40, 42, 44) which respectively have a plurality of inner contact devices, contact feet (400, 420, 440), which start from associated strip-like sections (402, 422, 442) and in this case make circuit-compliant contact with two substrates (5) electrically connected in parallel. Further, outer, contact devices (404, 424, 444) of the load connection elements (40, 42, 44) form the external connections of the power semiconductor module.
In this refinement, the load connection elements (40, 42, 44) are encased by an insulator (408, 428, 448) almost completely. This casing does not cover parts of the contact devices (400, 420, 440) for the interconnects (54) of the substrate (5) or the outer contact devices (404, 424, 444) for the external electrical connection of the power semiconductor module.
It may be preferred for exclusively the contact areas with the interconnects (54) not to be covered by insulator in the case of the contact feet (400, 420, 440) of the load connection elements (40, 42, 44) for the interconnects (54) of the substrate (5). It may likewise be preferred, as illustrated here, for a section of the contact feet (400, 420, 440) which extends from the substrate surface not to be encased. This region does not absolutely require insulation, or insulation can be formed by a potting compound, preferably made of a silicon gel, which is arranged inside the power semiconductor module, for example.
The outer contact devices (404, 424, 444) for making contact externally are not encased at least on the respective contact area for the electrically conductive connection. In this case too, the casing may have a cutout starting from the respective contact area in the direction of the respective strip-like section (402, 422, 442). The exact form of the casing (408, 428, 448) is dependent on the respective requirements from the insulation of the load connection elements (40, 42, 44) relative to one another and on the geometric form of the power semiconductor module, for example on its housing shape.
It is particularly advantageous if the respective casing (408, 428, 448) of the individual load connection elements (40, 42, 44) is formed using an injection-moulding or dipping process. As a requirement for the insulator itself, for example a polyamide-based thermoplastic, a tracking resistance with a CTI value of greater than 400, even better if greater than 600, has been found to be particularly suitable.
It is also particularly advantageous if the load connection elements (40, 42, 44) are preferably connected in the region of the strip-like sections (402, 422, 442) to form an assembly unit. This can be produced, by way of example, by connecting the individual load connection elements (40, 42, 44) encased with insulator (408, 428, 448) through bonding. However, it may also be preferred to encase a plurality of, advantageously all, load connection elements (40, 42, 44) with the insulator (408, 428, 448) in a joint process step. This produces an assembly unit which is particularly advantageous to process.
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In addition, the respective load connection elements (40, 42, 44) or a stack (4) of load connection elements (40, 42, 44) formed therefrom have recesses (406, 426, 446) preferably in the region of the strip-like sections (402, 422, 442). These recesses (406, 426, 446) are designed for passing through auxiliary connection elements (not shown), which are advantageously in the form of helical springs. In this case, it goes without saying that the edges of the recesses (406, 426, 446) formed are likewise encased with the insulator (408,428,448).
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WE CLAIM:
1. Power semiconductor module (1), for arrangement on a cooling component (2), having at least one substrate (5), at least two power semiconductor components (60) arranged thereon, a housing (3) and outwardly routed load (40, 42, 44) and control connection elements, where the substrate (5) has an insulator body (52) and the latter's first main area, facing the interior of the power semiconductor module, has interconnects (54) at load potential arranged on it, where the load connection elements are respectively in the form of a metal shaped body with outer contact devices (404, 424, 444), a strip-like section (402, 422, 442) and with inner contact devices (400, 420, 440) starting from said strip-like section, the inner contact devices extend from the strip-like section to the substrate (5) and make circuit-compliant contact therewith, and where the load connection elements (40, 42, 44), with the exception of the regions of the outer and inner contact devices, are completely encased by an insulator (408, 428, 448) and accordingly electrically insulated from one another.
2. Power semiconductor module (1) according to Claim 1, in pressure-contact form with a pressure device (70).
3. Power semiconductor module (1) according to Claim 1, where the insulator (408, 428,448) has a CTI value of more than 400.
4. Power semiconductor module (1) according to Claim 1, where the insulator (408, 428,448) is arranged using a dipping process.
5. Power semiconductor module (1) according to Claim 1, where the insulator (408, 428,448) is arranged using an injection-moulding process.
6. Power semiconductor module (1) according to Claim 1, where the load connection elements (40, 42, 44) form a stack (4) in the region of the strip-like sections (402,422,442).
7. Power semiconductor module (1) according to Claim 5, where the stack (4) is produced by bonding.
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8. Power semiconductor module (1) according to Claim 5, where the stack (4) is
produced by simultaneously arranging the insulator (408, 428, 448) on a plurality of load connection elements (40, 42,44).
9. Power semiconductor module (1) according to one of the preceding claims, where the pressure device (70) and/or the stack (4) have recesses (406, 426, 446, 466) for passing through auxiliary connection elements in the form of helical springs.
Dated this 25th day of May, 2007

HIRAL CHANDRAKANT JOSHI
AGENT FOR
SEMIKRON ELEKTRONIK GMBH & CO. KG
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ABSTRACT
The invention describes a power semiconductor module, for arrangement on a cooling component, having a substrate, at least two power semiconductor components arranged thereon, a housing and outwardly routed load and control connection elements. In this context, the substrate has an insulator body and the latter's first main area, facing the interior of the power semiconductor module, has interconnects at load potential arranged on it. The load connection elements are respectively in the form of a metal shaped body with outer contact devices, a strip-like section and with inner contact devices starting from said strip-like section. The inner contact devices extend from the strip-like section to the substrate and make circuit-compliant contact therewith. In addition, the load connection elements, with the exception of the regions of the outer and inner contact devices, are completely encased by an insulator and accordingly electrically insulated from one another.
To,
The Controller of Patents,
The Patent Office,
Mumbai
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(Figure 3)


Documents:

993-mum-2007-abstract(granted)-(29-11-2010).pdf

993-mum-2007-abstract.doc

993-mum-2007-abstract.pdf

993-mum-2007-cancelled pages(2-11-2010).pdf

993-MUM-2007-CLAIMS(AMENDED)-(2-11-2010).pdf

993-MUM-2007-CLAIMS(CANCELLED PAGES)-(2-11-2010).pdf

993-mum-2007-claims(granted)-(29-11-2010).pdf

993-MUM-2007-CLAIMS(MARKED COPY)-(2-11-2010).pdf

993-MUM-2007-CLAIMS(MARKED COPY)-(2-11-2010).tif

993-mum-2007-claims.doc

993-mum-2007-claims.pdf

993-mum-2007-correspondence(23-7-2007).pdf

993-mum-2007-correspondence(ipo)-(30-11-2010).pdf

993-mum-2007-correspondence(ipo)-(31-12-2009).pdf

993-mum-2007-correspondence-received.pdf

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

993-mum-2007-description(granted)-(29-11-2010).pdf

993-MUM-2007-DRAWING(2-11-2010).pdf

993-mum-2007-drawing(granted)-(29-11-2010).pdf

993-mum-2007-drawings.pdf

993-mum-2007-form 1(23-7-2007).pdf

993-mum-2007-form 2(granted)-(29-11-2010).pdf

993-mum-2007-form 2(title page)-(28-5-2007).pdf

993-mum-2007-form 2(title page)-(granted)-(29-11-2010).pdf

993-MUM-2007-FORM 3(2-11-2010).pdf

993-mum-2007-form 3(28-5-2007).pdf

993-mum-2007-form-1.pdf

993-mum-2007-form-18.pdf

993-mum-2007-form-2.doc

993-mum-2007-form-2.pdf

993-mum-2007-form-26.pdf

993-mum-2007-form-3.pdf

993-mum-2007-form-5.pdf

993-MUM-2007-PETITION UNDER RULE 137(2-11-2010).pdf

993-MUM-2007-REPLY TO EXAMINATION REPORT(2-11-2010).pdf


Patent Number 244284
Indian Patent Application Number 993/MUM/2007
PG Journal Number 49/2010
Publication Date 03-Dec-2010
Grant Date 29-Nov-2010
Date of Filing 28-May-2007
Name of Patentee SEMIKRON ELEKTRONIK GMBH & CO. KG
Applicant Address POSTFACH 820251, 90253 NURNBERG.
Inventors:
# Inventor's Name Inventor's Address
1 MARCO LEDERER KINDINGER STR.23, 90453 NURNBERG.
PCT International Classification Number H01L21/60;H01L21/02
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA