DE102016115221A1 - Method for connecting at least two substrates to form a module - Google Patents

Abstract

A method, comprising: providing at least a first and a second substrate, the substrates each having at least an upper and a lower surface, each at least partially opposed to the upper and the lower surface, and wherein the substrates each at least one surface at least one Have substrate region with at least one partially structured metal surface; and at least one wire; Forming at least a first bond connection over at least a first position, wherein the first bond connection is formed over at least a first region of the patterned metal surface of the first substrate, and wherein the first bond connection is formed between at least a first region of the wire and the first region of the patterned metal surface ; Applying the wire and a solder paste, wherein the wire is at least partially applied over the surface of the first substrate and wherein the solder paste is at least partially applied over at least a first portion of the patterned metal surface of the second substrate; wherein the application of the wire and the solder paste takes place successively or simultaneously; Placing the two substrates over each other such that at least a portion between the wire and the solder paste contacts and an assembly is formed; and heating the assembly to a temperature which is at least above the melting point of the solder paste.

Description

The present invention relates to a method for joining at least two substrates.

• – die Herstellung dieser Verbindung kosteneffizient und wenig fehleranfällig ist,
• – die Verbindung eine niedrige thermische und elektrische Impedanz aufweist,
• – die Verbindung eine definierte Höhe aufweist, um die beiden Metallisierungsschichten mit Hilfe dieser Höhe zu beabstanden, und dass
• – die Verbindung eine Flexibilität aufweist, welche Ermüdungserscheinungen während des Modulbetriebs vorbeugt und damit eine lange Lebensdauer gewährleistet.

The present invention is in the field of bonding techniques of substrates for electronic or power electronic modules. Currently there are power electronic modules that are designed for double-sided cooling, for this reason, at least two planarly arranged parallel to each other substrates. A hitherto unsolved technical problem in this case is to electrically, thermally and mechanically connect the metallization layers, which are located on the substrates on the side facing the respective opposite substrate, such that:

• The production of this compound is cost-effective and not prone to error,
• The connection has a low thermal and electrical impedance,
• - The compound has a defined height to space the two metallization layers using this height, and that
• - The compound has a flexibility that prevents fatigue during module operation, thus ensuring a long life.

• – Die Abstandshalter haben entweder rechteckigen Querschnitt oder sind kugelförmig. Beide geometrische Formen haben den Nachteil, schlecht fixierbar (da sie beidenends z.B. gelötet werden) zu sein, was Ausschuss und höhere Produktionskosten nach sich ziehen kann. Die Produktion von Abstandselementen mit rechteckigem Querschnitt ist ebenfalls vergleichsweise teuer und der mögliche Biegeradius von derartigen Abstandselementen ist stark begrenzt.
• – Die oben genannten Abstandshalter stellen lediglich punktförmige Verbindungen bereit,
• – die nur wenig mechanischen Druck aufnehmen können,
• – die einen vergleichsweise hohen thermischen Widerstand aufweisen, und
• – die eine vergleichsweise hohe Induktivität aufweisen.

Hitherto, connecting elements which are used to connect two electrically conductive surfaces of two substrates in a conductive manner and to keep them at a defined distance, according to the prior art, are characterized by the following disadvantages:

• - The spacers are either rectangular in cross section or spherical. Both geometric shapes have the disadvantage of being difficult to fix (since they are soldered at both ends, for example), which can lead to rejects and higher production costs. The production of spacers with rectangular cross section is also relatively expensive and the possible bending radius of such spacers is severely limited.
• The abovementioned spacers provide only punctiform connections
• - which can absorb only little mechanical pressure,
• - Which have a comparatively high thermal resistance, and
• - Have a comparatively high inductance.

To produce linear or surface connections would require a very large number of spacers. The resulting high number to be placed and with the help of soldering or gluing to be fixed spacers means a high production cost.

In document [1], for example, a power electronic module is disclosed, which is formed from two structured metallized substrates, on whose facing sides in each case at least one power semiconductor chip is applied, which are each contacted on the upper side by means of bonding wires electrically to a portion of the metallized surface of the substrate to which he is already contacted on the underside. The opposing power semiconductor chips are also contacted with a thermally and electrically conductive potting compound, which is applied only in the surface metallization of the power semiconductor chips. As a result, in particular the dynamic heat dissipation of the respective power semiconductor chip is improved. A soldering of the bonding wires is not provided. Commercially available electrically conductive epoxy potting compounds achieve only electrical conductivities (of about 1 Ωm (ohmmeter)), which are many orders of magnitude lower than those of pure metals.

• – Kontaktierung von Kupferbonddrähten sowohl per Bondverfahren wie auch per Lötverfahren, dadurch mechanisch sehr belastbare Verbindung mit hoher thermischer und elektrischer Leitfähigkeit;
• – Die Verbindung ist sofort nach Auflegen der Kupferbonddrähte mechanisch auf Druck belastbar und die nachfolgenden Prozessschritte können Druck auf die Verbindung ausüben um bspw. eine hohe Planparallelität der Substrate zu erreichen;
• – Herstellung der Verbindung sowohl zwischen Chipoberseite und metallisierter Substratoberfläche als auch zwischen verschiedenen metallisierten Substratoberflächen:
• – nur punktuelles/linienhaftes Dispensen von Lötpaste – die Lötpaste muss nicht in Position gehalten werden und die Gefahr von entstehenden Kurzschlüssen (insbesondere zwischen auf der Chip-Oberseite eng beieinander liegenden Anschlusspads [wie GATE und SOURCE bei MOSFET-Chips]) ist geringer als bei Verwendung von elektrisch leitfähiger Vergussmasse, die durch zusätzliche Maßnahmen/Arbeitsschritte vor Verlaufen geschützt werden muss (z.B. durch das sogenannte Dam & Fill-Verfahren)
• – nur punktuelle, bzw. linienhafte mechanische Verbindungen, die nicht flächenhaft sind und somit keine mit flächenhaften Verbindungen einhergehenden Probleme hinsichtlich der thermischen Ausdehnungskoeffizienten und dem dadurch hervorgerufenen mechanischen Stress aufweisen;
• – die gelötet/gebondeten Verbindungselemente (Bonddrähte) können auch über die Abmessungen der Substrate hinausgehend als elektrische/thermische Verbindungselemente genutzt werden; und
• – die erfindungsgemäße Verbindungstechnik zweier Substrate basiert hinsichtlich der mechanischen, elektrischen und thermischen Verbindung auf intermetallischen Verbindungen – organische Materialien wie Epoxidharz können darüber hinaus gehend zur Versiegelung des Moduls eingesetzt werden, sind jedoch nicht zwingend notwendig und für die Funktion des Moduls nicht unabdingbar – somit kann eine höhere zulässige Betriebstemperatur erreicht werden.

In contrast to [1], the present application with the features according to claim 1 provides the following advantages and is distinguished as follows:

• - Contacting of Kupferbonddrähten both by bonding methods as well as by soldering, thereby mechanically very strong bond with high thermal and electrical conductivity;
• - The compound is mechanically loaded immediately after applying the Kupferbonddrähte pressure and the subsequent process steps can exert pressure on the compound to, for example, to achieve a high parallelism of the substrates;
• Preparation of the connection both between chip top side and metallized substrate surface and between different metallized substrate surfaces:
• - only selective / linear dispensing of solder paste - the solder paste does not need to be held in position and the risk of short circuits (especially between on the chip top closely spaced connection pads [such as GATE and SOURCE for MOSFET chips]) is lower than at Use of electrically conductive potting compound, which must be protected against bleeding by additional measures / work steps (eg by the so-called Dam & Fill method)
• - Only punctual, or linear mechanical connections that are not planar and thus have no problems associated with areal connections problems in terms of thermal expansion coefficient and the mechanical stress caused thereby;
• - The soldered / bonded fasteners (bonding wires) can also be used beyond the dimensions of the substrates as electrical / thermal fasteners; and
• - The bonding technique of the invention of two substrates based on the mechanical, electrical and thermal connection based on intermetallic compounds - organic materials such as epoxy resin can also be used to seal the module, but are not mandatory and for the function of the module is not essential - thus a higher permissible operating temperature can be achieved.

The problem of keeping two metallized ceramic substrates at a distance, for example in order to produce a module cooled on both sides, has hitherto been solved in the prior art by, for example, cuboid (see [2], [3], [4] and [5 ]) or spherical (see [6], [7] and [8]) spacers punctual mechanical, electrical and thermal contact between power semiconductors and / or metallized substrate surfaces produce. The spacers typically provide spacings in the range of a few hundred microns. In particular, at low voltages to be isolated is completely dispensed spacers (see [9]).

Thus, the object is to provide a method which enables a cost-efficient production of connections of two opposing substrates, each with at least one electrically conductive surface, while increasing the system power density and a reduction in the power of such modules.

This object is achieved by the method according to the features of the independent claims. Related claims give advantageous embodiments again. Advantageous developments, which can be implemented individually or in any combination, are shown in the dependent claims.

Hereinafter, the terms "comprise," "include," or "include," or any grammatical variations thereof, are used in a non-exclusive manner. Accordingly, these terms may refer to situations in which, in addition to the features introduced by these terms, there are no other features or to situations in which one or more other features are present. For example, the expression "A denotes B", "A includes B" or "A includes B" can both refer to the situation in which, apart from B, there is no further element in A (ie to a situation where in which A consists exclusively of B), as well as the situation in which, in addition to B, one or more further elements in A are present, for example element C, elements C and D or even further elements.

It is further to be understood that the terms "at least one" and "one or more" and grammatical variations of these terms, when used and to be used in connection with one or more elements or features, are intended to provide the element or feature in a single or multiple way can usually be used only once, for example, at the first introduction of the feature or element. In a subsequent re-mention of the feature or element, the corresponding term "at least one" or "one or more" is generally no longer used, without limiting the possibility that the feature or element may be single or multiple.

Furthermore, the terms "preferably", "in particular", "for example (for example)" or similar terms are used below in connection with optional features, without restricting alternative embodiments thereof. Thus, features introduced by these terms are optional features, and it is not intended by these features to limit the scope of the claims and, in particular, the independent claims. Thus, as those skilled in the art will recognize, the invention may be practiced using other embodiments. Similarly, features introduced by "in one embodiment" or by "in another embodiment" are to be understood as optional features without, however, being construed as limiting alternative embodiments or the scope of the independent claims. Furthermore, these introductory expressions are intended to preserve all possibilities of combining features introduced thereby with other features, be they optional or non-optional features.

Starting point is the task of mechanically connecting two substrates plane-parallel with a previously defined distance and with electrical and thermal contact at certain points.

This means according to the invention that at least one power module has at least one first (ceramic) substrate and one second (ceramic) substrate, which are arranged plane-parallel to one another. They each have at least one structured metallization layer or metal surface on the side corresponding to each facing another substrate. At least one or more spacer elements are located between the metallization layers or metal surfaces, for example at least one wire which is / are characterized in that these spacer elements or the at least one wire are at least partially made of, for example solderable, copper bonding wire consist / is / are; each at least once, but preferably both ends, each with a bond or multiple bonds on one of the metallization layers or metal surfaces mechanically strong, electrically and thermally conductive, are applied; in the substrate plane straight and / or bent, or may be arbitrarily shaped; bent by guiding the bonding head and deposited on the first substrate; subsequently deformed (for example, squeezed) or adjusted with another technical device; and be electrically and thermally conductively connected by means of a soldering process with at least one metallic surface or metal surface.

• a) einen definierten Abstand zwischen der ersten elektrisch leitfähigen Oberfläche und einer zweiten leitfähigen Oberfläche (z.B. eines ersten Substrates oder eines auf einem ersten Substrat aufgebrachten Chips) herzustellen;
• b) eine elektrische und thermische Verbindung zwischen der ersten elektrisch leitfähigen Oberfläche und einer zweiten elektrisch leitfähigen Oberfläche (z.B. eines ersten Substrates oder eines auf einem ersten Substrat aufgebrachten Chips) herzustellen;
• c) die elektrische Verbindung durch möglichst weite Ausdehnung senkrecht zum Stromfluss niederinduktiv zu gestalten; und
• d) die thermische Verbindung durch eine möglichst lang ausgebildeten Abstandshalter und damit einen hohen Verbindungsquerschnitt niederimpedant (Z_th) bzw. niederresistiv (R_th) zu gestalten.

In other words, it is disclosed that the at least one spacer or wire by means of at least one, but usually with at least two Drahtbondverbindungen (ie the area in the wire and metallization form a mechanical or cohesive and electrically and thermally conductive connection) is applied to an electrically conductive surface (eg a first substrate or a chip deposited on a first substrate) and serves to:

• a) produce a defined distance between the first electrically conductive surface and a second conductive surface (eg, a first substrate or a chip deposited on a first substrate);
• b) produce an electrical and thermal connection between the first electrically conductive surface and a second electrically conductive surface (eg, a first substrate or a chip deposited on a first substrate);
• c) to make the electrical connection by expanding as far as possible perpendicular to the current flow niederinduktiv; and
• d) to make the thermal connection by a spacer formed as long as possible and thus a high connection cross-section niederimpedant (Z _th ) or low-resistance (R _th ).

• a) zuvor in einem Siebdruckverfahren mit anschließenden Trocknungs- und Brennprozessen auf dem Substrat aufgebracht ist; b) entlang ihrer größten Ausdehnungen zumindest teilweise strukturiert ist, um eine zuvor bestimmte Schaltung (zwischen Chips, Bondverbindungen, Zwischenkreiskondensatoren u.a.) abzubilden;
• c) entlang ihrer geringsten Ausdehnung entweder eine gleichmäßige Dicke oder unterschiedliche Dicken aufweist, d.h. die den unterschiedlichen zu führenden Stromstärken mit unterschiedlichen Auflösungen hinsichtlich der Strukturbreite und der einzustellenden Abstände zwischen den elektrisch leitfähigen Strukturelementen Rechnung trägt; und
• d) bspw. durch isolierende Dickschichten von anderen Kupferdickschichtbereichen elektrisch isoliert sein kann.

In addition, the metallization of the substrates is preferably a copper thick layer which:

• a) previously applied in a screen printing process with subsequent drying and firing processes on the substrate; b) is at least partially structured along its largest dimensions in order to image a previously determined circuit (between chips, bond connections, DC link capacitors, etc.);
• c) has either a uniform thickness or different thicknesses along its smallest dimension, ie that takes into account the different current strengths to be conducted with different resolutions in terms of structure width and the distances between the electrically conductive structural elements to be set; and
• d) can be electrically isolated, for example, by insulating thick layers of other Kupferdickschichtbereichen.

• – Im Gegensatz zur „stud-bump“-Technik, werden erfindungsgemäß wedge-Bonds eingesetzt, an welchen ein signifikant langer Draht verbleibt. Dieser wird durch die anzahlmäßig wenigen weiteren wedge-Bonds arretiert und teilweise erst in folgenden Verfahrensschritten (Löten, sintern) vollständig oder teilweise elektrisch, mechanisch und thermisch mit anderen elektrisch und thermisch leitfähigen Teilen verbunden.
• – Im Vergleich zu „stud-bumps“ können daher mit weniger Bondfüßen größere Abstände überspannt werden, die Verbindungen sind linear, bzw. flächig und verfügen damit über einen großen Querschnitt für Stromtransport und Wärmeabfuhr.
• – Die „Flip-Chip“-Technik setzt Gold-„stud-bumps“ ein, um auf einer nicht lötfähigen Oberfläche (z.B. Al) eine Lötung zu erlauben. Die erfindungsgemäße Anwendung zielt nicht darauf ab, die Lötbarkeit herzustellen, sondern eine niederimpedante (elektrische und thermische) Verbindung zwischen zwei leitfähigen Oberflächen herzustellen. Die Verwendung von Kupfer-Bonddrähten (Cu-Bonddrähten) erlaubt jedoch auch die Kontaktierung Al-beschichteter(Chip-)Oberflächen.

The method according to claim 1 is different from conventional so-called "stud-bump" or "flip-chip" technologies as follows:

• In contrast to the "stud-bump" technique, according to the invention wedge bonds are used, on which a significantly long wire remains. This is locked by the numerically few other wedge bonds and partially only in the following process steps (soldering, sintering) completely or partially electrically, mechanically and thermally connected to other electrically and thermally conductive parts.
• - Compared to "stud-bumps" larger distances can therefore be covered with fewer bond feet, the connections are linear or flat and thus have a large cross-section for power transport and heat dissipation.
• The "flip-chip" technique uses gold "stud-bumps" to allow soldering on a non-solderable surface (eg Al). The application according to the invention is not intended to produce the solderability but to produce a low-impedance (electrical and thermal) connection between two conductive surfaces. However, the use of copper bonding wires (Cu bonding wires) also allows the contacting of Al-coated (chip) surfaces.

That is, the method according to the subject matter of claim 1 for the first time enables electrical and mechanical contacting of a spacer by means of wire bonding technology prior to further manufacturing steps, which electrically and thermally contact the spacer using other bonding techniques (soldering, sintering) with other contact surfaces. In addition, the method according to claim 1 allows for the first time in the field of power modules, the use of Drahtbondtechnik and soldering, or sintering for fixing one and the same component (spacer) with different parts of the overall system (metallized surfaces). In addition, in contrast to the prior art such as so-called "stud-bumps" provides the so-called "wedge-bond" connection technique according to the invention for a surface connection of the substrates, but at least preferably for at least two bonding connections per bonding wire. Furthermore, the method according to claim 1 allows for the first time the use of a wire to metallized surfaces that are plane-parallel to its longest extent, electrically, thermally and mechanically connect. In addition, the method according to the subject-matter of claim 1 enables the use of the copper thick-film technique for double-sided cooled modules and bonding of copper thick-wire to one side of one of the copper thick film-coated ceramic substrates.

The resulting advantages include the fact that the round cross-section of the respective spacer or wire can be produced in large quantities in a cost-efficient and with high precision, since wires are mass-produced. In addition, the round cross section is bendable in narrow radii with almost no change in diameter and can therefore also image complex connection structures within the module. That Under the proviso no or only small change in cross section in the bending area, wires have low bending radii compared to non-circular cross sections. In addition, the round cross-section of the wire reduces mechanical stress peaks, for example, especially with respect to solder joints. Furthermore, Cu bond wires in some diameters are already conventional standard products, i. the availability of a large number of different diameters is thus likely to be present, at least in the near future, with advantages in terms of flexibility and cost of such a process. Moreover, a bond according to the method of claim 1 prevents any slippage of the spacer during the individual manufacturing operations, thus causing less waste and allowing more precise processes, which in turn enables more compact module designs to be realized.

This means that the method according to claim 1, the cost-efficient production of compounds of two, opposing substrates, each with at least one electrically conductive surface allows and increasing the system power density by reducing the space requirement of contacting elements in that the tasks of electrical and mechanical contacting by a single element, or an element combination is obtained. In addition, the method according to claim 1 enables the reduction of the power to weight by reducing the number of components, as well as the production costs of power electronic systems by reduced assembly costs (fewer screw and plug connections), as well as the electromagnetic radiation by current conduction in two plane-parallel substrates and use of the outer metallizations as electrical shielding.

In one embodiment, a method is provided, comprising:
Providing at least a first substrate and a second substrate, the substrates each having at least an upper surface and a lower surface, each facing at least partially the upper surface and the lower surface, and wherein the substrates each comprise at least one surface on at least one substrate region having at least one partially textured metal surface;
and at least one wire;
Forming at least a first bond connection over at least a first position, wherein the first bond connection is formed at least partially over at least a first region of the patterned metal surface of the first substrate, and wherein the first bond connection between at least a first region of the wire and the first region of the patterned metal surface is formed;
Applying the wire and a solder paste, wherein the wire is at least partially applied over the surface of the first substrate over which the first bond has been formed, and wherein the solder paste is applied at least partially over at least a first portion of the patterned metal surface of the second substrate is, wherein the application of the wire and the solder paste takes place successively or simultaneously;
Arranging the first substrate and the second substrate over each other such that at least a portion of the wire and a portion of the solder paste touch and form an assembly;
and
Heating the assembly such that a temperature acts on the assembly, wherein the temperature is at least above the melting point of the solder paste and wherein the resulting solder joint mechanically, electrically and thermally connects at least a portion of the wire and a portion of the patterned metal surface of the second substrate.

Thereby, the metallized portions of the at least two substrates are mechanically, electrically and thermally connected to each other, wherein a defined by the wire diameter distance between the metallized portions of the two substrates is prepared. This distance is necessary, for example, to allow fluid, non-electrically conductive media to penetrate between the metallized surfaces of the two substrates and dissipate heat therefrom. In addition, the wire diameter can be chosen so the diameter corresponds to the thickness of the power semiconductor chip applied to the metallization of the first or the second substrate, including its electrical top and bottom side contacting (bonding wires, bonds, soldering, sintered connections). As a result, mechanical pressure, which is applied from the outside to the two substrates, for example, to achieve good thermal contact with one or more cooling or heating elements, better distributed and pressure or mechanical stress peaks are avoided.

The bond formed is preferably a wedge-bond which is formed by the application of ultrasonic energy and pressure of the wire to the metallized surface. In addition to ultrasound, heat can also be supplied to make the bond. For the production of a variety of bonding machines are available that can handle Kupferbonddrähte.

In a further embodiment, the wire is at least partially applied over the surface of the first substrate over which the first bonding compound is formed, to at least a second position over at least a second region of the patterned metal surface of the first substrate; and wherein at least one second bond is formed at at least the second position, and wherein the second bond is formed between at least a second portion of the wire and the second portion of the patterned metal surface of the first substrate.

As a result, the wire is securely held on the metallized surface of the first substrate and slippage during subsequent process steps (soldering, sintering, gluing, potting) is reliably avoided.

In a further embodiment, the first bond connection and the second bond connection are arranged adjacent to one another.

As a result, almost closed wire loops can be formed, with the term wire loop herein describing a wire arrangement between two bond connections whose wire length between the bond connections is longer than the distance between the bond connections, which, for example, can delimit certain areas within the module. These areas can be sealed gas- and fluid-tight when the soldering according to the invention takes place between the wire and both opposing metallised surfaces along the entire length of the wire.

In a further embodiment, the first bond connection and the second bond connection are arranged spatially separated from one another.

As a result of the physical separation of the at least two bonding connections, at least one opening in the wire ring can be provided so that gaseous or fluid media can flow through this opening and / or electrical signals can be guided by means of further bonding wires and / or metallization structures.

In a further embodiment, the wire is at least partially applied over the surface of the first substrate, over which or on which the first bonding compound is applied, that a distance in the range of 0.1 mm to 50 between the surface and the wire mm is formed.

In this way, at least one bonding loop can be formed, which can be used to produce a defined distance between the first and the second substrate or / and to provide a mechanical, electrical and thermal connection between the first and second substrate, which is mechanically flexible, whereby thermal induced mechanical stresses can be reduced and the service life of the connection can be increased.

In a further embodiment, after at least the first bonding compound is formed, the wire is at least partially applied over the surface such that a gap is formed between the surface and the wire in a range of 0.1 mm to 100 mm, the wire forms loops between the bond connections (the wire length between the bond connections is longer than the distance between the bond connections)

and wherein the wire is at least partially fixed by at least one or more solder and / or bonding connections to metallized surfaces.

The additional fixation of the wire by soldering increases the mechanical stability. Soldering or soldering can be arranged directly in the region of the bond connection or at any other point on the surface of the wire, and a mechanical layer can be provided for one or more metallized structured surfaces located on the substrates or for the metallization layers provided on the substrates to make electrical and thermal connection. Through areas of closed soldering, ie soldering, both the metal-facing surfaces facing the wire and the wire mechanically, electrically and thermally connect, can prevent fluid media, gaseous media and in particular organic potting materials penetrate these areas. For example, this can be dispensed with during casting with a ceramic-filled epoxy on an additional mold.

In a further embodiment, after arranging the first substrate and the second substrate one above the other, such a predetermined pressure is applied to the first substrate and / or the second substrate that at least partially deforms the spaced part of the wire, and wherein the pressure before and / or during and / or after the soldering process is applied.

In another embodiment, the pressure is maintained until completion of the soldering operation.

By means of these aforementioned embodiments, manufacturing-related differences in the height of bond loops, power semiconductor chips and other components arranged between both substrates can be compensated. For this purpose, the heights of the bond loops are made slightly larger during their production than the defined heights of the other components arranged between the two substrates. The applied pressure plastically deforms the bond loops, securely touching both metallized surfaces of the substrates facing them.

In another embodiment, the amount of pressure before and / or during and / or after the soldering process is varied.

This serves to initially cause any existing elastic deformations and then fix them by at least one solder joint or soldering. As a result, a mechanical bias is built up, which is helpful for the achievement of static mechanical pressures, for example in the connection of the substrates with externally disposed heat sinks.

The previously determined pressure or contact pressure is preferably to be selected or defined as follows:
The previously determined pressure or contact pressure is present when this pressure is applied to the arrangement or acts on it, so that all bond loops of the arrangement, which are located on one of the metallized surfaces of the substrates on the side facing the respective opposite substrate form mechanical, electrical and thermal contact of the metallized surface of the opposite substrate to which they are not connected by bond.

In addition, optionally or additionally, this applied pressure or the contact pressure can be increased to such an extent that the bonding loops thereby mechanically deform and the mechanical, electrical and thermal contact area between the metallized substrate surfaces and the bonding wire increases even further.

In a further embodiment, in addition to the bond connection with at least one electronic component having at least one region with an at least partially structured metal surface, the wire is electrically and thermally conductively connected over this region.

As a result, metallized tops or metal surfaces of electronic or electronic power semiconductor devices with metallized surfaces of the substrates can be mechanically, electrically and thermally connected, whereby the integration of components of different heights in the volume enclosed by the substrates is possible. For this example, bonding wires with different diameters, or deformed by pressing wires, used.

In a further embodiment, the electrically conductive connection of the electronic component and the wire is provided by means of at least one joining technique from the group of joining techniques, this group comprising: soldering, gluing and bonding.

By soldering in addition to the previously prepared bonds, the thermal and electrical conductivity can be increased. In addition, the thermal impedance is improved.

In another embodiment, the electronic device is disposed at least partially over one of the substrates, and wherein the electronic device is connected to at least one metallized surface from the group of bonding techniques by at least one bonding technique, the group comprising soldering, sintering, and bonding.

The backside metallization of the electronic component can be sintered onto the surface metallization of the second substrate facing it. This sintered connection has an advantageously low thermal and electrical resistance.

In a further embodiment, the metal surfaces are each applied with different layer thicknesses to the substrates, and wherein the metal surfaces are each formed with electrically isolated regions.

The structuring of the metallized substrate surfaces or metal surfaces can also take place in the height or the thickness of this layer. For example, various thicknesses of the copper metallization can be achieved by thick film technology. By means of different thicknesses of the metallization, it is possible to use components of different overall height between the substrates with only one wire diameter, or to connect them mechanically, electrically and thermally to the metallic surfaces facing them.

In another embodiment, the space between the first substrate and the second substrate is at least partially filled with a filler of the group of fillers, the group comprising: organic fill material, epoxy, air, dried air, and / or a fluid, non-electrically conductive medium.

The filler increases the thermal conductivity and provides additional electrical insulation. A fluid filling material displaces gases from the volume, which is trapped by the two substrates.

Advantageously, all embodiments of the methods described and claimed herein may be implemented in combination with one or more of the embodiments recited and described herein.

Other embodiments, their configuration, as well as some of the advantages associated with these and other embodiments, will be better understood by the following detailed description with reference to the accompanying figures. The figures are merely schematic representations of embodiments of the invention

figure description

Further details and features of the present invention will become apparent from the following description of an embodiment, in particular in conjunction with the dependent claims. In this case, the respective features can be implemented on their own or in combination with one another. The invention is not limited to the embodiments.

The embodiments are shown schematically in the following figures. Here, like reference numerals in the figures designate the same or functionally identical elements or with respect to their functions corresponding elements.

Hereby show:

1 a schematic diagram of an embodiment of the method according to claim 1;

2 a schematic representation of method steps according to an embodiment;

3 a schematic cross-sectional view and a plan view of another embodiment;

4 four schematic cross-sectional views of further embodiments;
and

5 a schematic cross-sectional view of another embodiment.

Detailed description

In the following, the same reference numerals describe the same components or devices, devices, arrangements and / or modules, which may be formed from the same materials or may have the same chemical or physical properties.

1 shows a schematic flow diagram of an embodiment of a method 100 comprising:
Providing at least a first substrate and a second substrate, the substrates each having at least an upper surface and a lower surface, each facing at least partially the upper surface and the lower surface, and wherein the substrates each comprise on at least one surface at least one substrate region having at least one partially textured metal surface; and at least one wire ( 110 );
Forming at least a first bond connection over at least a first position, wherein the first bond connection is formed at least partially over at least a first region of the patterned metal surface of the first substrate, and wherein the first bond connection between at least a first region of the wire and the first region of the patterned metal surface is formed ( 120 );
Applying the wire and a solder paste wherein the wire is at least partially over the surface of the first substrate over which the first bonding compound is arranged, and wherein the solder paste is at least partially applied over at least a first portion of the patterned metal surface of the second substrate, wherein the application of the Wire as well as the soldering paste in succession or simultaneously ( 130 );
Arranging the first substrate and the second substrate one above the other such that at least one Touched area of the wire and a portion of the solder paste and thus an arrangement is formed ( 140 );
and
Heating the assembly such that a temperature acts on the assembly, wherein the temperature is at least above the melting point of the solder paste, wherein the resulting solder joint mechanically, electrically and thermally connects at least a portion of the wire and a portion of the patterned metal surface of the second substrate ( 150 ).

The method described above allows the metallized portions, i. Areas of the structured metal surfaces, the substrates mechanically or cohesively, electrically and thermally connected to each other. In addition, at least on account of the given wire diameter, a defined distance is provided between the metallized partial regions or metal surfaces of the substrates. This distance makes it possible, for example, fluid, non-electrically conductive media to penetrate between the metallized surfaces or metal surfaces of the substrates and dissipate heat therefrom. In addition, the wire diameter can be selected such that it corresponds to the thickness of the power semiconductor chip applied to the metallization of at least the first or the second substrate, including its electrical top and bottom side contacting (bonding wires, bonds, soldering, sintered connections). As a result, mechanical pressure, which is applied from the outside to the two substrates, for example. To achieve a good thermal contact with one or more cooling or heating elements, better distributed and pressure or mechanical stress peaks are avoided.

As a result, the wire is securely held on the metallized surface of the first substrate and slippage during subsequent process steps (soldering, sintering, potting) is reliably avoided.

However, more than two substrates may be provided for the method described herein. In addition, the generic terms metal surface, metallization and metallized surface are used synonymously herein. The surfaces, i. the opposing upper surface and lower surface, respectively, lie substantially plane-parallel.

The substrates are preferably ceramic substrates, but not exclusively ceramic substrates, ie they can also be any substrates with a ceramic coating, wherein the substrates comprise at least one substrate material from the group of substrate materials or are formed therefrom, the group comprising: oxide ceramics ( Al ₂ O ₂ ), non-oxide ceramics (eg AlN), insulator-coated metals (eg Insulated Metal Substrates - IMS), plastics and composite materials (eg printed circuit board material FR4).

The at least one metal surface or metallization or metallic surface, which is / are at least partially formed over or on at least one area of the substrate surfaces, comprises or is at least one metal or a metal alloy from the group of metals or metal alloys wherein the group comprises: copper, gold, silver, aluminum, iron, platinum, nickel, palladium, tin.

The metallization or metal surfaces are set up in such a way that they are electrically conductive or thermally conductive.

The structure of the structured metal surface (s) or metallization (s) or metallic surface (s) may in a preferred embodiment as structured Kupferdickfilmmetallisierung or metallizations by means of at least one conventional application and patterning process over or on at least a portion of the substrate surface be formed.

The at least one wire is arranged such that it is electrically as well as thermally conductive. The wire may have any cross-sectional shape, but preferably a circular cross-section. The wire comprises or is formed from at least one wire material from the group of wire materials, the group comprising: copper, gold, silver, platinum, or alloys of these and other metallic materials.

The at least one material for the metallization (s) or metal surface (s) and the wire may be either solderable or not solderable. The wire must be solderable if this according to process step 150 to be contacted by soldering.

That the at least one first bonding connection is formed over a first region or a position lying within this region of the structured metal surface or metallization of the first substrate.

The wire or bonding wire or copper wire is applied by means of a conventional bonding machine or a bonding machine above or on the surface of the first substrate, above which the first bonding connection is already arranged. That is, the wire is at least partially passed on at least partially by the first bonding connection via the aforementioned surface of the first substrate. In this case, the wire may also project at least partially beyond the substrate surface. Of the Wire can be either completely guided on the surface, ie, adjacent to the surface, applied, or at least partially guided over the surface to form a space between the aforementioned surface and the wire. The distance may be in a range of about 0.05 mm to 50 mm, or the distance may be in a range of about 0.1 mm to 10 mm. When applied, the wire may be applied in any geometric shape over the aforementioned surface, ie, the wire may be straight, curved, circular, triangular, rectangular, or any other n-cornered shape (n denotes any natural number) or applied in any free form over or on the aforementioned surface.

The solder paste for making at least one later solder joint is at least partially applied to at least a first region, i. both the first substrate and the second substrate may have either one or more of such areas that apply the patterned metal surface by means of a conventional solder paste application method.

The solder paste comprises at least one of the group of solder paste materials, or at least partially formed thereof, the group comprising: copper, tin, silver, lead, indium.

The application of the wire as well as the solder paste can be either sequential or parallel in time, i. take place simultaneously. That the application can be carried out in two parallel process steps or the application of the wire and the solder paste is carried out in two successive process steps. In the case of staggered application of wire and solder paste, first the wire and then the solder paste may be applied, or first the solder paste and then the wire.

The substrates are arranged one above the other in such a way that an arrangement forms therefrom with at least one region or a point at which the wire and the solder paste form a contact point, so that at this contact point a solder joint in the subsequent process step by means of heating the arrangement thus formed can be formed.

The heating of the assembly is performed such that a temperature acts on the assembly, which is at least above the melting temperature of the solder paste, whereby a solder joint of solder paste and wire is formed, so that formed following this process step, a material connection between wire and solder paste becomes. Thus, besides the mechanical, i. cohesive, compound to provide a thermally and / or electrically conductive connection.

The claimed method 100 It also makes it possible, depending on the volume of the at least one wire or the at least one bond compound and the amount of material applied to solder paste and the number of positions at which the solder paste was applied, as well as the duration and temperature during heating, at least one solder joint manufacture. Such a solder joint thus formed allows, for example, the entire wire and its corresponding bonds, which have no direct contact with the underlying surface, ie, which are exposed before heating to completely enclose with solder paste. With appropriate bonding, the bond (s) will be described herein with which the wire has been affixed at least by means of the bonding compound (s) at or above a substrate. In addition, it is also possible, in a further embodiment, for example, to at least partially enclose wire and / or bond connections or also to form punctiform connections between wire and solder paste.

In a further embodiment, the wire is at least partially applied over the surface of the first substrate over which the first bonding compound is formed to at least a second position over at least a second region of the patterned metal surface of the first substrate. Wherein at least one second bond connection is formed at at least the second position, and wherein the second bond connection is formed between at least a second region of the wire and the second region of the structured metal surface of the first substrate.

This makes it possible to securely hold the wire on the metallized surface or metal surface of the first substrate and reliably prevent slippage during and during subsequent process steps (such as, for example, soldering, sintering and / or casting).

In addition, it is possible by at least one additional bond that the wire is fixed more resilient, which can, for example, a variety of additional forms when applying the wire over or on the substrate surface can be realized. In other words, a change in the position of the already applied wire in a change in direction after forming an additional bond can be avoided, which is why it can also be used to implement complex forms when applying it, for example. If The wire is to be applied around a wide variety of electronic components around on the substrate surface.

In a further embodiment, the first bond connection and the second bond connection are arranged adjacent to one another.

This embodiment makes it possible to form almost closed wire loops which, for example, delimit certain areas within the module. For example, these regions can be sealed in a gas-tight and fluid-tight manner if the soldering according to the invention takes place between the wire and both opposing metallized surfaces over the entire wire length. That It can be formed by a hermetic seal.

In a further embodiment, the first bond connection and the second bond connection are arranged spatially separated from one another.

Due to the formed spatial separation of the at least two bonding connections, this embodiment makes it possible to provide at least one opening in the wire ring so that gaseous or fluid media can flow through this opening and / or electrical signals can be guided by means of further bonding wires and / or metallization structures.

In a further embodiment, the wire is at least partially applied over the surface of the first substrate, over which or on which the first bonding compound is applied, that a distance in the range of 0.1 mm to 50 between the surface and the wire mm is formed.

This forms at least one bond loop, i. a wire loop or bond loop over the o.g. Surface, which makes it possible to produce a defined distance between the first and the second substrate and / or to form a mechanical, electrical and thermal connection between at least the one first substrate and the at least one second substrate, which is mechanically flexible, whereby thermally induced reduces mechanical stresses and the service life of the connection can be increased. Such a wire or bond loop allows a spring action, i. a defined elasticity between the substrates, the elasticity being defined by the wire properties and the shape of the wire or bonding loop.

In a further embodiment, after at least the second bonding compound is formed, the wire is at least partially applied over the surface such that a distance in the range of 0.1 mm to 100 mm is formed between the surface and the wire, the wire forms loops between the bond connections (the wire length between the bond connections is longer than the distance between the bond connections) and wherein the wire is at least partially fixed by soldering and / or bonding connections to at least one metallized surfaces.

The at least one additional fixation of the wire by means of soldering increases the mechanical stability. Solder joints may be disposed directly in the area of the bond or at any other location on the surface of the wire and provide mechanical, electrical and thermal bonding to one or more metallized patterned surfaces on the substrates.

Furthermore, through areas of closed solder or solder, i. Soldering or soldering joints that mechanically, electrically and thermally connect the metallized surfaces facing the wire and prevent the wire, for example, fluid media, gaseous media and, in particular, organic potting materials, from penetrating these areas, whereby, for example, during a subsequent process step in which a casting of the arrangement by means of potting materials, for example. With a ceramic-filled epoxy, is performed, can be dispensed with an additional mold.

In a further embodiment, after arranging the first substrate and the second substrate one above the other, such a predetermined pressure is applied to the first substrate and / or the second substrate that at least partially deforms the spaced part of the wire, and wherein the pressure before and / or during and / or after the soldering process.

In another embodiment, the pressure is maintained until completion of the soldering operation.

By means of these aforementioned embodiments, manufacturing-related differences in the height of bond loops, power semiconductor chips and other components arranged between the two substrates can be compensated or adjusted. For this purpose, the heights of the bond loops are made slightly larger during their production than the defined heights of the other components arranged between the two substrates. The applied pressure plastically deforms the bond loops, securely touching both metallized surfaces of the substrates facing them.

In another embodiment, the pressure is varied during placement and soldering.

This serves to initially cause any existing elastic deformations and then fix them by at least one solder joint or soldering. As a result, a mechanical bias is built, which is helpful for achieving static mechanical pressures, for example in the connection of the substrates with externally disposed heat sinks.

The previously determined pressure or contact pressure is preferably to be selected or defined as follows:
The previously determined pressure or contact pressure is present when this pressure is applied to the arrangement or acts on it, so that all bond loops of the arrangement, which are located on one of the metallized surfaces of the substrates on the side facing the respective opposite substrate form mechanical, electrical and thermal contact of the metallized surface of the opposite substrate to which they are not connected by bond.

In addition, optionally or additionally, this applied pressure or the contact pressure can be increased to such an extent that the bonding loops thereby mechanically deform and the mechanical, electrical and thermal contact area between the metallized substrate surfaces and the bonding wire increases even further.

In a further embodiment, in addition to the bond connection with at least one electronic component having at least one region with an at least partially structured metal surface, the wire is electrically and thermally conductively connected over this region.

As a result, metallized tops or metal surfaces of electronic or electronic power semiconductor devices with metallized surfaces of the substrates can be mechanically, electrically and thermally connected, whereby the integration of components of different heights in the volume enclosed by the substrates is possible. For this example, bonding wires with different diameters, or deformed by pressing wires are used.

The electronic or power-electronic components which can be connected to the described method comprise at least one element from the group of electronic or power-electronic component or are formed from one or more such elements, the group comprising: MOSFET, JFET, HEMT, PIN diode, Schottky diode, bipolar transistor, IGBT, thyristor.

In a further embodiment, the electrically conductive connection of the at least one electronic component or a plurality of electronic components and at least one wire is formed by means of at least one connection technique from the group of connection techniques, this group comprising: soldering and bonding.

By soldering in addition to the previously prepared bonds, the thermal and electrical conductivity can be increased. In addition, the thermal impedance is improved.

In a further embodiment, the at least one electronic component or the plurality of electronic components is arranged at least partially over one of the substrates, the electronic component being connected to at least one metallized surface from the group of connection techniques by means of at least one connection technique comprising: soldering, sintering and gluing.

The backside metallization of the electronic component can be sintered onto the surface metallization of the second substrate facing it. This sintered connection has an advantageously low thermal and electrical resistance. Adhesive connections enable a cost-effective and fast connection.

In a further embodiment, the metal surfaces are each applied with different layer thicknesses over or onto the substrates, and wherein the metal surfaces are each formed with electrically isolated regions.

The structuring of the metallized substrate surfaces or metal surfaces can also take place in the height or the thickness of this layer. For example, different thicknesses of the copper metallization can be provided by thick film technology (for example, copper thick film technology). By different thicknesses of the metallization, it is possible with only one wire diameter components of different heights, which are arranged between the substrates, use, or mechanically, electrically and thermally connect to their respective facing metallic surfaces or metal surfaces.

In a further embodiment, the space between the first substrate and the second substrate is at least partially filled with a filling material from the group of filling materials, the group comprising: organic filling material, Epoxy, air, dried air and / or a fluid, non-electrically conductive medium.

This embodiment allows the filler material to increase thermal conductivity and also provides additional electrical isolation. The filling material displaces, for example, gases from the volume, which is enclosed by the two substrates.

2 shows a schematic representation of process steps of a method 200 , marked with the reference numerals 200A to 200D , According to one embodiment, as well as two further embodiments thereof with the reference numerals 200D -A and 200D -B marked.

In the 2 disclosed method steps of the method 200 ie 200A to 200D , and the embodiments formed thereby 200D -A and 200D -B comprise all the features and preambles of the general and detailed description disclosed above, in particular the detailed description of 1 , This therefore also includes all the generic terms disclosed therein, the disclosed apparatus, methods, method steps and elements or components, the materials disclosed above and their physical and chemical properties.

In step 200A becomes a wire 214 with a circular cross-section on a substrate 212 , For example, a ceramic substrate, with at least partially metallized surface over or on the one metal surface 213 is applied, arranged. Subsequently, in step 200B the wire 214 by means of a first bond connection 216 with the metal surface 213 electrically and thermally conductively connected, whereby a first arrangement is formed. After that, in step 200C a second arrangement is formed, which consists of a second substrate 218 with a metal surface 219 and a solder paste applied over it 220 is formed, and then arranged over the first arrangement. The two above-mentioned arrangements are arranged one above the other in such a way that at least the wire 214 and the solder paste 220 face each other so that by merging the above two arrangements of the wire 214 and the solder paste 220 touch at least at one point or together then have a contact point. In step 200D For example, by heating the aforesaid arrangements to at least one temperature higher than the melting point of the solder paste, a mechanical, cohesive, electrically and thermally conductive connection is formed whereby the assemblies are firmly joined together.

The further embodiment 200D -A shows an arrangement obtained by the method 200 (Steps 200A - 200D ) was formed and thus a mechanical or cohesive, electrically and thermally conductive connection between a wire 214 and the solder paste 220 , where the wire 214 by means of a bond connection 216 also mechanically or cohesively as well as electrically and thermally conductive with the metal surface 213 of the first substrate 212 is connected, and wherein the solder joint in turn a mechanical or cohesive, electrically and thermally conductive connection with the metal surface 219 of the second substrate 218 forms. In addition, the amount of material was solder paste 220 and the temperature for heating the assembly for in step 200D -A chosen connection such that thereby the bonding connection 216 , as well as the wire 214 completely from the solder joint 220 is enclosed.

The further embodiment 200D -B shows an arrangement obtained by the method 200 (Steps 200A - 200D ) was formed and thus a mechanical or cohesive, electrically and thermally conductive connection between a wire 214 and the solder paste 220 , where the wire 214 by means of a bond connection 216 also mechanically or cohesively as well as electrically and thermally conductive with the metal surface 213 of the first substrate 212 is connected, and wherein the solder joint in turn a mechanical or cohesive, electrically and thermally conductive connection with the metal surface 219 of the second substrate 218 forms. In addition, the amount of material was solder paste 220 and the temperature for heating the assembly for in step 200D -A chosen connection such that thereby the wire 214 at least partially from the solder joint 220 is enclosed, wherein the bond 216 free from the solder joint 220 remains.

3 shows a schematic cross-sectional view and a plan view of another embodiment. That is, it is a schematic cross-sectional view 300A and a corresponding schematic plan view 300B a device 300 in 3 represented by one of the previously described methods 100 ( 1 ) respectively. 200 ( 2 ) was formed. That is, the method by which the device 300 comprises all features and generic terms of the general and detailed description disclosed above, in particular the detailed description of 1 and 2 , Thus, this also includes all of the generic terms disclosed herein, the disclosed apparatus, methods, method steps, and elements or components, and the corresponding materials disclosed above, and their physical and chemical properties.

With A and B are respectively the corresponding planes of view for the schematic cross section 300A and the schematic plan view of the device 300 characterized.

The schematic cross-sectional view 300A and the schematic plan view 300B shows exemplified a module or an arrangement by means of a method of the aforementioned method 100 respectively. 200 according to 1 and or 2 was formed.

In the schematic cross-sectional view 300A and in the schematic plan view 300B the device 300 an exemplary arrangement or module is shown, which (s) a first substrate 310 and a second substrate 320 both substrates are preferably ceramic substrates, each having a lower structured metallization, 314 and 324 , In addition, the first substrate points 310 several electrically and / or thermally insulated upper structured metallizations 312 on. Likewise, the second substrate 320 several electrically and / or thermally insulated upper structured metallizations 322 on. The two substrates, 310 and 320 , and their respective structured metallizations, 312 . 314 . 322 and 324 , are arranged one above the other so that the two structured metallizations 312 and 324 spaced apart. The distance is here by three wire bonds 301 (For example, copper wire bonds), or wires 302 , defined between the two substrates, 310 and 320 , and their respective facing structured metallizations, 324 and 312 , are arranged. The wire bonds 301 are each with the corresponding area of the upper structured metallization 312 of the first substrate 310 connected by means of at least one bond mechanically or cohesively and electrically and thermally conductive. In addition, the wire bonds 301 each with the corresponding region of the lower structured metallization 324 of the second substrate 320 connected by means of at least one solder joint mechanically or cohesively and electrically and thermally conductive, wherein one of the solder joints 401 one of the wire bonds 301 completely encloses. It is also in 300A and 300B a wire 302 , in particular a copper bonding wire, which provides or forms at least one electrically and / or thermally conductive connection out of the arrangement or the module. Furthermore, there are two electronic components 330 , in particular two power semiconductor chips, each with topside and underside metallization, in 300A and 300B shown. The electronic components 330 each have a mechanical or cohesive and thermally and / or electrically conductive connection 400 in particular at least one soldering, sintering and / or adhesive connection, which is formed by means of at least one joining technique from the group of joining techniques, the group comprising: soldering, sintering and gluing.

4 shows four schematic cross-sectional views, marked with 400A to 400D , further embodiments. That is, there are four schematic cross-sectional views, 400A . 400B . 400C and 400D , in each case a device in 4 each represented by one of the previously described methods 100 ( 1 ) respectively. 200 ( 2 ) were formed. That is, in turn, the method with which the devices 400A . 400B . 400C and 400D have each been formed comprises all the features and preambles of the above-disclosed general and detailed description, in particular the detailed description of 1 and 2 , Thus, this also includes all of the generic terms disclosed herein, the disclosed apparatus, methods, method steps, and elements or components and the corresponding materials disclosed above, as well as their physical and chemical properties.

400A shows a first substrate 310 and a second substrate 320 , each one facing a structured metallization 312 and 324 exhibit. Between the two substrates, 310 and 320 , is a wire 302 , in particular a copper wire, whose diameter measures the distance between the two metallizations, 324 and 312 , defines or sets and the by means of wire bond 301 at each one of its two ends with the respective corresponding region of the upper structured metallization 312 of the first substrate 310 is fixed. Between the two wire bonds 301 is the wire 302 each by means of a solder joint 401 along the entire length, extending between the areas where the wire bonds 301 are located, extends, with the respective corresponding region of the respective metallization, 314 and 322 , mechanically or cohesively and electrically and thermally conductively connected.

400B shows a first substrate 310 and a second substrate 320 each comprising a lower structured metallization and an upper structured metallization, 324 and 312 exhibit. Between the two substrates, 310 and 320 , is a wire 302 , in particular a copper wire, whose diameter measures the distance between the two metallizations, 324 and 312 , defines or sets and the by means of wire bond 301 at each one of its two ends with the respective corresponding region of the upper structured metallization 312 of the first substrate 310 is fixed. Between the two wire bonds 301 is the wire 302 each by means of several solder joints 401 , which are each spaced apart, ie spatially separated, over the entire length extending between the areas where the wire bonds 301 are arranged, extends, with the respective corresponding area of the respective metallization, 324 and 312 , mechanically or cohesively and electrically and thermally conductively connected.

400C shows a first substrate 310 and a second substrate 320 each comprising a lower structured metallization and an upper structured metallization, 324 and 312 , exhibit. Between the two substrates, 310 and 320 , is a wire 302 , In particular a copper wire, arranged by means of wire bond 301 at its two ends with the respective corresponding region of the upper structured metallization 312 of the first substrate 310 is fixed. The wire 302 is so between the two wire bonds 301 bent, that between the two wire bonds a wire loop is formed. That is, the wire 302 between the two wire bonds 301 a distance over the entire length between the two wire bonds 301 having. Between the two wire bonds 301 is the wire 302 by means of a solder joint 401 , with the respective corresponding area of the lower structured metallization 324 of the second substrate 320 , mechanically or cohesively and electrically and thermally conductively connected. In addition, there is a solder joint 401 at least next to a first wire bond 301 formed, which is a mechanical or cohesive and electrically and thermally conductive connection in the region of the additional solder joint 401 next to a wire bond 301 provides.

400D shows a first substrate 310 and a second substrate 320 each comprising a lower structured metallization and an upper structured metallization, 324 and 312 , exhibit. Between the two substrates, 310 and 320 , is a wire 302 , in particular a copper wire, arranged by means of several wire bonds 301 at its two ends and in-between with the respective corresponding areas of the upper structured metallization 312 of the first substrate 310 is fixed. In addition, the wire 302 so between the two wire bonds 301 bent several times, that between the two wire bonds at the ends of the wire a multiplicity of wire loops are formed, whereby in each case the areas, which the upper structured metallization 312 touch, with this each by means of wire bond 301 mechanically or cohesively and electrically and thermally conductive are connected. That is, the wire 302 between the two wire bonds 301 several times a previously determined distance over the entire length between the two wire bonds 301 forms. In the corresponding areas where the wire 302 the lower structured metallization 324 of the second substrate 320 contacted or touched, is the wire 302 by means of at least one solder joint 401 connected mechanically or cohesively and electrically and thermally conductive.

5 shows a schematic cross-sectional view, marked with 500 , with a further embodiment. That is, it is a cross-sectional view 500 a device in 5 represented by one of the previously described methods 100 ( 1 ) respectively. 200 ( 2 ) was formed. That is, in turn, the method with which the device 500 comprises all the features and generic terms of the general and detailed description disclosed above, in particular the detailed description of 1 and 2 , Thus, this also includes all of the generic terms disclosed herein, the disclosed apparatus, methods, method steps, and elements or components and the corresponding materials disclosed above, as well as their physical and chemical properties.

The schematic cross-sectional view 500 shows a first substrate 310 and a second substrate 320 each having a lower structured metallization, 314 and 324 , and an upper structured metallization, 312 and 322 , exhibit. In this case, the lower structured metallization 314 a plurality of spatially separated areas. The lower structured metallization 324 provides different thicknesses or heights or has different heights or thicknesses and is structured in at least two spatially separate areas. The upper structured metallization 312 is structured in this example into four spatially separated areas.

Between the two substrates, 310 and 320 , are seven wires 302 , in particular copper wires arranged.

Two of the wires 302 are bent and act as wire loops. Both wire loops made from the wires 302 are formed, each at its two ends by means of wire bonds 301 connected with a structured metallization mechanically or cohesively and thermally and electrically conductive. A first of these two wires is at both ends by means of bonds 301 with the lower metallization 324 of the second substrate 320 connected. A second of these two wires is at both ends by means of bonds 301 with the upper metallization 312 of the first substrate 310 connected. In addition, each of the wire loop formed as defined above in the description of 1 and 4 , at its highest elevation, which they are applied over the metallized surfaces, to the respective bonding compounds, with the respectively opposite structured metallization, by means of at least one solder joint 410. connected mechanically or cohesively and thermally and electrically conductive. Thus, a first of these two wires is at its elevation by means of solder joints 401 with the upper metallization 312 of the first substrate 310 connected. So is a second of these two wires at his elevation by means of solder joints 401 with the lower metallization 324 of the second substrate 320 connected.

Furthermore, each is a solder joint 401 at least next to the two wire bonds 301 formed, in each case an additional mechanical or cohesive and electrically and thermally conductive connection in the region of the additional solder joint 401 next to a wire bond 301 provides.

Two wires 302 Form an additional spacer between an electronic component 330 resting on an area of upper textured metallization 312 of the first substrate 310 is fixed by means of at least one soldering or sintering or adhesive bond, and the lower structured metallization 314 is arranged. These two wires are by means of a solder joint 401 completely enclosed and thus form a mechanical or cohesive and thermally and electrically conductive connection between the electronic component 330 and the lower structured metallization 314 , The electronic component 330 is also still with an additional area, that of the area on which the electronic component 330 is arranged, spatially separated or thermally and electrically isolated, the upper structured metallization 312 of the first substrate 310 thermally and electrically conductive by means of a wire 302 connected. This wire 302 is with one of its two ends on the surface of the electronic component 330 mechanically or cohesively and thermally and / or electrically conductively connected by means of a wire bond or a solder joint. This wire 302 is also at its other end with the previously described spatially separated or thermally and electrically isolated region of the top structured metallization 312 of the first substrate 310 mechanically or cohesively and thermally and / or electrically conductively connected by means of a wire bond or a solder joint.

Furthermore, there are two wires 302 the seven wires each by means of a wire bond 301 each with a structured metallization, 312 respectively. 324 , mechanically or cohesively and electrically and thermally conductively connected. Ie one of these two wires 302 is with the metallization 312 and the other wire 302 is with the metallization 324 mechanically or cohesively and electrically and thermally conductive in each case by means of Drahtbondverbindung 301 connected, whereby an electrical or thermal connection from the device 500 is provided.

Referenced literature:

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• [2] DE 10 2004 018 476 B4 ,
• [3] US Pat. No. 7,911,792 B2 ,
• [4] DE 10 2014 117 762 A1 ,
• [5] H. Sato, F. Kato, H. Nakagawa, H. Yamaguchi, S. Rejeki and F. Lang, "Development of SiC Power Modules for High-Speed Switching Operation," 2013 IEEE Electrical Design of Advanced Packaging Systems Symposium (EDAPS) , Nara, (2013), pp. 13-16, doi: 10.1109 / EDAPS.2013.6724445 ,
• [6] M. Mermet-Guyennet, A. Castellazzi, P. Lasserre and J. Saiz, "3D Integration of Power Semiconductor Devices based on Surface Bump Technology," Integrated Power Systems (CIPS), 2008 5th International Conference on, Nuremberg, Germany, 2008 , pp. 1-6 ,
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• [8th] WO 1998 015 005 A1 ,
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LIST OF REFERENCE NUMBERS

100

Method according to claim 1

110

First method step according to claim 1

120

Second method step according to claim 1

130

Third method step according to claim 1

140

Fourth method step according to claim 1

150

Fifth method step according to claim 1

200

Schematic representation of method steps according to the invention

200A

Schematic representation of a method step according to the invention

200B

Schematic representation of a method step according to the invention

200C

Schematic representation of a method step according to the invention

200D

Schematic representation of a method step according to the invention

200D-A

 Schematic representation of another embodiment

200D-B

 Schematic representation of another embodiment

214

Wire or bonding wire

212

First substrate

213

First metal surface or metallization of the first substrate

216

Bond connection between the wire and the metal surface

218

Second substrate

219

Second metal surface or metallization

220

Solder paste, especially on metal surface and / or bonding wire applied solder paste

222

Molten solder paste, i. the solder paste after heating according to claim 1

300

Schematic views of another embodiment, i. a device which is formed by a method according to the invention

300A

Schematic cross-sectional view of the device according to one embodiment

300B

Schematic plan view of the device according to an embodiment

301

Cross section of a wire bond, in particular a copper wire bond, or wire bond

302

Cross section of a wire, in particular a copper bonding wire, or wire

310

First substrate, in particular first ceramic substrate

312

Upper structured metallization or metal surface of a first substrate

314

Lower structured metallization or metal surface of a first substrate

320

Second substrate, in particular second ceramic substrate

322

Upper structured metallization or metal surface of a second substrate

324

Lower structured metallization or metal surface of a second substrate

330

Power semiconductor chip with topside and underside metallization

400

Compounds, in particular soldering, sintering and / or adhesive bonds

401

solder connections

400A

Schematic representation of another embodiment

400B

Schematic representation of another embodiment

400C

Schematic representation of another embodiment

400D

Schematic representation of another embodiment

500

Schematic representation of another embodiment

Claims (13)

A method, comprising: a) providing i) at least a first substrate and a second substrate, (1) wherein the substrates each have at least an upper surface and a lower surface, (2) each at least partially the upper surface and the lower surface and (3) the substrates each having on at least one surface at least one substrate region having at least one partially structured metal surface; and (ii) at least one wire ( 110 ); b) forming at least a first bond connection over at least a first position; i) wherein the first bond connection is formed at least partially over at least a first region of the patterned metal surface of the first substrate, and ii) the first bond connection between at least a first region of the wire and the first region of the structured metal surface of the first substrate is formed ( 120 ); c) applying the wire and a solder paste i) wherein the wire is at least partially applied over the surface of the first substrate over which the first bond is disposed, ii) the solder paste at least partially over at least a first portion of the patterned metal surface of the second Substrate is applied, and iii) wherein the application of the wire and the solder paste takes place successively or simultaneously ( 130 ); d) arranging the first substrate and the second substrate one above the other in such a way that at least one area of the wire and at least one area of the solder paste touches and thus an arrangement is formed ( 140 ); and e) heating the assembly such that a temperature acts on the assembly, the temperature being at least above the melting point of the solder paste, wherein the resulting solder joint mechanically, electrically, at least a portion of the wire and at least a portion of the patterned metal surface of the second substrate and thermally connecting ( 150 ). Method according to claim 1, a) wherein the wire is at least partially applied over the surface of the first substrate over which the first bonding is formed to at least a second position over at least a second region of the patterned metal surface of the first substrate; and b) wherein at least one second bonding compound is formed at at least the second position, and wherein the second bonding bond is formed between at least a second region of the wire and the second region of the patterned metal surface of the first substrate.  The method of claim 2, wherein the first bonding compound and the second bonding compound are disposed adjacent to each other.  The method of claim 2, wherein the first bonding compound and the second bonding compound are spatially separated.  A method according to any one of claims 1 to 4, wherein the wire is at least partially over the surface of the first substrate, over which the first bonding is applied, that between the surface and the wire a distance in a range of 0.1 mm to 50 mm is formed.  Method according to one of claims 2 to 5, a) after having formed at least the first bonding compound, the wire is at least partially applied over the surface such that a distance in the range of 0.1 mm to 100 mm is formed between the surface and the wire; b) wherein the wire between the bonds forms at least one wire loop; and c) wherein the wire is at least partially fixed by soldering and / or bonding to at least one metallized surface. Method according to one of claims 5 or 6, a) wherein after arranging the first substrate and the second substrate one above the other, such a predetermined pressure on the first substrate and / or the second substrate is applied, that at least partially deforms the spaced part of the wire; and b) wherein the pressure takes place before and / or during and / or after the soldering process. The method of claim 7, wherein the pressure is varied during placement and soldering. Method according to one of claims 1 to 8, wherein the wire is connected in addition to the bonding connection with at least one electronic component with at least one region with an at least partially structured metal surface over this area electrically and thermally conductive.  The method of claim 9, wherein the thermally and electrically conductive connection of the electronic component and the wire is formed by means of at least one joining technique from the group of bonding techniques, this group comprising soldering and bonding.  Method according to one of claims 9 or 10, a) wherein the electronic component is at least partially disposed over one of the substrates; and b) wherein the electronic device is connected to at least one metallized surface by means of at least one joining technique from the group of bonding techniques, the group comprising soldering, sintering and bonding.  Method according to one of claims 1 to 11, a) wherein the metal surfaces are each applied with different layer thicknesses to the substrates, and b) wherein the metal surfaces are each formed with electrically isolated regions.  The method of claim 1, wherein the space between the first substrate and the second substrate is at least partially filled with a filler of the group of fillers, the group comprising: organic filler, epoxy, air, dried air, and / or a fluid , non-electrically conductive medium.

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