WO2019170211A1

WO2019170211A1 - Method for producing a sandwich arrangement

Info

Publication number: WO2019170211A1
Application number: PCT/EP2018/055246
Authority: WO
Inventors: Michael Schäfer; Nadja Pelshaw; Yvonne LÖWER; Anton-Zoran Miric
Original assignee: Heraeus Deutschland GmbH & Co. KG
Priority date: 2018-03-05
Filing date: 2018-03-05
Publication date: 2019-09-12

Abstract

The invention relates to a method for producing a sandwich arrangement consisting of a first component having a contact surface A, a second component having a contact surface D, and solder between the contact surfaces A and D, the solder being produced by melting a solder deposit connected to one of the components, on the contact surface A or D, and subsequent cooling of the molten solder at the solidification temperature thereof, a fixing agent consisting of a fixing agent composition having been previously applied to the contact surface A or D which is not connected to the solder deposit and/or to the free contact surface of the solder deposit, and the solder deposit being arranged with the free contact surface thereof facing the contact surface A or D which is not connected to the solder deposit. Said fixing agent composition consists of between 0 and 97 wt. % of at least one solvent selected from the group consisting of water and organic solvents boiling at ≤ 285°C, between 3 and 100 wt. % of at least one material M1 selected from the group consisting of (i) thermoplastic organic polymers that are meltable between 30 and 180°C and (ii) non-polymer organic compounds without acid groups, which are meltable between 30 and 180°C, between 0 and 20 wt. % of at least one material M2 selected from the group consisting of (iii) organic polymers that are not meltable between 30 and 180°C and (iv) non-polymer organic compounds without acid groups, which are not meltable between 30 and 180°C and do not have a boiling point or have a boiling of above 285°C, and between 0 and 30 wt. % of at least one inorganic solid filler. In the absence of at least one constituent (i) in the at least one material M1 1500 µm2, the sum of the surface portions, provided with the fixing agent, of the contact surface A or D forming a common overlapping surface with the free contact surface of the solder deposit, amounts to 50 surface % of the common overlapping surface, while in the sole absence of at least one constituent (ii) in the at least one material M1 1500 µm2, said sum amounts to 100 surface % of the common overlapping surface.

Description

Method for producing a sandwich arrangement

The invention relates to a method for producing a sandwich assembly comprising a first component connected via solder to a second component.

Soldering as a method for integrally joining components is known to the person skilled in the art. In particular, it is a method to connect components used in electronics via a respective contact surface mechanically and thermally and electrically conductive with each other. The solder material used may be a solder paste or placed solder preform located between the components to be connected, which is melted into molten solder in an oven and, after leaving the furnace, cooling and solidification, results in the desired connection of the components. Alternatively, a solder paste applied to a component or placed solder preform can first be converted into a solder deposit connected to a contact surface of the component. The solder deposit connected to the contact surface of the component has an outwardly facing free contact surface and can thus serve as a soldering connection to the further component enabling solder material. For this purpose, it can be melted in an oven to molten solder and after leaving the furnace, cooling and solidification form the desired compound of the components. The problem is that when moving the assembly of component or elements and Lotvorform, for example during transport into the oven, to an undesirable change in position between Lotvorform and

can come connecting components; The situation is not different when moving or transporting an arrangement made of solder deposit equipped component and thus to be connected further component. In the worst case, a component can not only move to Lotvorform and connected to the device or against a solder deposit or assume a tilt, but even solve and fall down. Causes can be, for example, vibrations or acceleration or deceleration during transport.

US 2010/0313416 A1 discloses a method for producing a solder joint between two electronic components, wherein having a flux effect Adhesive layer between the solder bumps of an electronic component and the electrode to be connected to the other electronic component is used. As components of the adhesive layer, thermosetting resin in combination with a flux-effect chemical compound is disclosed.

US 5,177,134 discloses the use of an adhesive suitable for temporary bonding of electronic components with flux properties in solder joining the electronic components. An essential component of the adhesive is a 2,2-disubstituted succinic acid

US 5,152,451 discloses the use of a resin-based flux suitable for temporary bonding of electronic components in the context of soldering the electronic components. US 2004/0152238 A1 discloses the use of an adhesive having flux in the reflow soldering of chips and substrates.

The object of the invention is the development of a method for producing a sandwich assembly of two components with solder therebetween, in which a fixing agent is used as intermediary, which dispenses with the use of a flux and the production of a satisfactory

Solder connection between the two components allowed. In the context of the present disclosure, "satisfactory solder joint" means a

Solder joint without or with only a small amount of voids defects at the interface between the component and the solder, depending on the number and size. Such

Lunkerfehlstellen can mechanical, electrical and / or the

interfere with thermally conductive connection. The fixative should preferably be used in a relatively small amount. It has been found that the method according to the invention disclosed below can achieve the object. One of the keys to the solution lies in the use of a flux which is not to be confused, that is to say no flux, because no flux action (ie, no dissolving or eliminating solder oxide or solder oxide layer before and / or during soldering) Effect), can be applied from a fixative composition fixative for fixing a device equipped with a solder deposit device to another device during a per se known process for the conversion of solder deposit in the components connecting solder, in particular during related transport steps. It has been shown that the fixing means allows a fixation in the sense of a temporary sufficient adhesion of a device equipped with solder deposit on a so to be soldered further component, which expresses itself in practice as a significantly reduced production of reject compared to working without fixative. Incidentally, as has also been shown, the use of fixative means dispenses with the use of complex mechanical fixation devices. It has also been shown that the use of the fixing agent corresponding to the method according to the invention produces small to tolerable influences on the mechanical, thermal or electrical connection and performance of finished components produced using solder deposit components

Sandwich assemblies of components has.

The process of the invention disclosed below can be carried out without the use of flux.

The method according to the invention is a method for producing a sandwich arrangement comprising a first component having a contact surface A, a second component having a contact surface D and solder located between the contact surfaces A and D,

wherein the solder is formed by melting a solder deposit connected to the contact surface A or D with one of the components and then cooling the solder

molten solder is made below its solidification temperature,

wherein previously a fixer of a Fixiermittelzusammensetzung on the not connected to the solder deposit contact surface A or D and / or on the free

Contact surface of the solder deposit is applied,

the solder deposit being arranged with its free contact surface facing the contact surface A or D not connected to the solder deposit,

wherein the fixer composition is 0 to 97% by weight (% by weight) of at least one solvent selected from the group consisting of water and organic solvents boiling at <285 ° C., 3 to 100% by weight of at least one material M1 selected from the group consisting of ( i) in the range of 30 to 180 ° C meltable thermoplastic organic polymers and (ii) in the range of 30 to 180 ° C fusible non-polymeric organic compounds without acidic groups,

0 to 20 wt .-% of at least one material M2 selected from the group consisting of (iii) in the range of 30 to 180 ° C non-meltable organic polymers and (iv) non-meltable in the range of 30 to 180 ° C non-polymeric organic compounds without acidic groups and without boiling point or with a boiling point above 285 ° C, and

0 to 30 wt .-% of one or more inorganic solid fillers, wherein the sum of the provided with the fixing surface portions of the free contact surface of the solder deposit a common overlap surface forming contact surface A or D in the presence of one or more components (i) in the at least a material M1 1500 pm ² to 50 area% of the common

Overlap area, while said sum in the sole presence of one or more components (ii) in the at least one material M1 is 1500 pm ² to 100 area% of the common overlap area.

The terms "organic compound" and "organic polymer" as used herein may also include substances having organic and inorganic moieties; purely inorganic substances are not included in the terms. The term "polymers" used herein also includes oligomers; both should not be confused with non-polymeric compounds. The boundary between oligomers and polymers is defined herein by the weight average molecular weight determinable by GPC (gel permeation chromatography, polystyrene standards, polystyrene gel as the stationary phase, tetrahydrofuran as the mobile phase). Polymers have a weight average molecular weight M w over 1000, for example in the range from 1000 to 300 000, oligomers have a weight average molecular weight M w of <1000, for example in the range from 500 to <1000. In contrast to polymers and oligomers, non-polymeric compounds are low molecular weight compounds having a defined sum and structural formula. As used herein, "without acidic groups" means without

Functionalities that function as a proton donor and can form H ₃ O ⁺ ions in water, such as carboxyl groups, sulfonic acid groups, phenolic OH groups, and the like. The term "without boiling point" used herein in connection with compounds of type (iv) refers to those having only a decomposition point or range instead of a boiling point.

In the method according to the invention is thus one with a solder deposit on his

Contact surface A respectively D equipped device with the free contact surface of the solder deposit to the contact surface D respectively A to be connected

Applied component facing, wherein said fixing means is located between the contact surfaces to be connected. Thereafter, the solder deposit is melted and the molten solder so formed is cooled below its solidification temperature, thereby forming the final soldered sandwich.

In the context of the invention, the term "component" is preferably to include individual parts. These items are preferably not further dismantled. In particular, the components are components or components used in electronics. The components have contact surfaces, in particular metallic contact surfaces.

Hierin is between a device with a contact surface A and a different or different from it distinguishable component with a

Contact area D distinguished. In order to prevent misunderstandings, components with a contact surface can not be distinguished from one another only if they are identical, when viewed as free components, or if they are arranged symmetrically with respect to one another. Do not lie in each other more symmetrical Arrangement before, so identical components can be distinguished from each other.

The device with a contact surface A and the device with a

Contact area D may be of the same type, i. For example, in both cases they can be substrates, or they can be active or passive components or an active and a passive component. However, it can also be that the component with a contact surface A is a substrate and the component with a contact surface D is an active or passive component, or vice versa. The substrates, the active and the passive components are in particular parts that are used in electronics.

For example, the following embodiments can be distinguished:

Examples of substrates are IMS substrates (insulated metal substrates), direct copper bonded substrates (DCB),

Ceramic substrates, PCBs (printed circuit boards) and leadframes. The sizes of the contact surfaces are for example in the range of 0.01 to 200 cm ² . The shape of the contact surfaces can be arbitrary, for example, round, hexagonal, triangular, preferably rectangular.

Examples of active components are diodes, LEDs (light emitting diodes,

Light-emitting diodes), dies (semiconductor chips), IGBTs (insulated-gate bipolar transistors, Insulated Gate Bipolar Transistors), ICs (Integrated Circuits, Integrated Circuits), and MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). The sizes of the contact surfaces are for example in the range of 0.01 to 200 cm ² . The shape of the contact surfaces can be arbitrary, for example, round, hexagonal, triangular, preferably rectangular.

Examples of passive components are sensors, bottom plates, heat sinks, connectors (eg clips), resistors, capacitors, inductors and antennas. The sizes of the contact surfaces are for example in the range of 0.01 to 200 cm ² . The shape of the contact surfaces can be arbitrary, for example, round, hexagonal, triangular, preferably rectangular.

Lot is solder metal, such as tin or tin rich

Alloys. Examples of tin-rich alloys are those with a tin content, for example in the range of 90 to 99.5 wt .-%. Examples of alloying metals are copper, silver, indium, germanium, nickel, lead, bismuth and antimony. The alloys may be leaded or lead free. Lead-free alloys may, for example, be selected from the group consisting of SnAg, SnBi, SnSb, SnAgCu, SnCu, SnSb, InSnCd, InBiSn, InSn, BiSnAg or SnAgCuBiSbNi.

For example, lead-containing alloys may be selected from the group comprising SnPb and SnPbAg. The melting temperatures of the solders may for example be in the range of 150 to 500 ° C, in particular 170 to 350 ° C.

In a first embodiment, the method according to the invention comprises the successive steps:

(1) providing a first device having a contact surface A, a second device having a contact surface D, a fixer composition as aforesaid (i.e., suitable for applying the fixative), and a solder paste;

(2) applying the solder paste to the contact surface A,

(3) melting the applied solder paste to form molten solder,

(4) cooling the molten solder below its solidification temperature to form a solder deposit having a free contact area X, (5) applying the fixer of the fixer composition to the

Contact surfaces X and / or D,

(6) Fierstellen a sandwich assembly of the two components with the solder deposit in between and with the fixing between the

Contact surfaces X and D,

(7) melting the solder deposit to form molten solder, and

(8) cooling the molten solder below its solidification temperature to form a sandwich of the two components joined via their contact surfaces A and D and the solidified solder therebetween.

Solder pastes are paste-form solder materials known to the person skilled in the art, for example, which can be applied by printing, jetting, dispensing, dipping, the essential components of which are solder particles and flux compositions. In a second embodiment, the method according to the invention comprises the successive steps:

(2) applying the solder paste to the contact surface D,

(3) melting the applied solder paste to form molten solder,

(4) cooling the molten solder below its solidification temperature to form a solder deposit having a free contact area Y,

(5) applying the fixer of the fixer composition to the

Contact surfaces Y and / or A,

(6) producing a sandwich assembly of the two components with the solder deposit located therebetween and with the fixing between the

Contact surfaces Y and A,

(7) melting the solder deposit to form molten solder, and

(8) cooling the molten solder below its solidification temperature to form a sandwich of the two components joined via their contact surfaces A and D and the solidified solder therebetween. In a third embodiment, the method according to the invention comprises the successive steps:

(1) providing a first device having a contact area A, a second device having a contact area D, a fixer composition as aforesaid (i.e., suitable for applying the fixative), and a solder preform each having discrete fixation means

Contact surfaces B and C,

(2) optionally applying the fixing agent from the

Fixing agent composition on the contact surfaces A and / or B,

(3) placing the solder preform with its contact surface B on the contact surface A with the optionally located between the contact surfaces A and B fixing agent,

(4) melting the fixed solder preform to form molten solder,

(5) cooling the molten solder below its solidification temperature to form a solder deposit having a free contact area X,

(6) applying the fixing agent from the fixer composition to the

Contact area X and / or the contact area D,

(7) producing a sandwich assembly of the two components with the solder deposit in between and with the fixing between the

Contact surfaces X and D,

(8) melting the solder deposit to form molten solder, and

(9) cooling the molten solder below its solidification temperature to form a sandwich of the two components joined via their contact surfaces A and D and the solidified solder therebetween. Lotvorformen is solder metal in the form of molded parts,

For example, solder metal foil, solder metal tape, solder metal plate or

Lotmetallzylinder. The solder preforms have discrete contact surfaces B and C, i. they are separate and distinguishable contact surfaces B and C, for example on opposite sides of a Lotvorform

arranged contact surfaces B and C. The sizes of the contact surfaces of the type B and C are each, for example, in the range of 0.01 to 200 cm ² . The shape of the contact surfaces of the type B and C can be arbitrary, for example round,

hexagonal, triangular, preferably rectangular. The thickness of the solder preform may be, for example, in the range of 10 to 750 pm.

Herein, the term "provided with fixing agent" or "not provided with fixing agent" is used. It states whether or not one or more relevant contact surfaces are provided with fixative or are free thereof, in other words, whether fixative has been applied to one or more respective contact surfaces or not.

In a fourth embodiment, the method according to the invention comprises the successive steps:

Contact surfaces B and C,

(2) optionally applying the fixing agent from the

Fixing agent composition on the contact surfaces C and / or D,

(3) placing the solder preform with its contact surface C on the contact surface D with the optionally located between the contact surfaces C and D fixing agent,

(4) melting the fixed solder preform to form molten solder,

(5) cooling the molten solder below its solidification temperature

Formation of a solder deposit with a free contact surface Y,

(6) applying the fixing agent from the fixer composition to the contact surface Y and / or the contact surface A,

Contact surfaces Y and A,

(8) melting the solder deposit to form molten solder, and

(9) cooling the molten solder below its solidification temperature to form a sandwich of the two components joined via their contact surfaces A and D and the solidified solder therebetween.

In a fifth embodiment, the method according to the invention comprises the successive steps: (1) providing a first device having a contact surface A, a second device having a contact surface D, a fixative composition as aforesaid (ie, suitable for applying the fixative), and a discrete contact surface B and C solder preform, one or both of which from the fixer composition applied fixing are provided

(2) optionally applying the fixing agent from the

Fixing agent composition on the contact surface A,

(3) Placing the Lotvorform with its contact surface B on the contact surface A optionally with the located between the contact surfaces A and B.

Fixer,

(4) melting the fixed solder preform to form molten solder,

(6) applying the fixing agent from the fixer composition to the

Contact area X and / or the contact area D,

Contact surfaces X and D,

(8) melting the solder deposit to form molten solder, and

(9) cooling the molten solder below its solidification temperature to form a sandwich of the two components joined via their contact surfaces A and D and the solidified solder therebetween. In a sixth embodiment, the method according to the invention comprises the successive steps:

(1) providing a first device having a contact surface A, a second device having a contact surface D, a fixer composition as aforesaid (ie, suitable for applying the fixative), and a solder preform having discrete contact surfaces B and C, one or both of which the fixative composition applied fixative are provided

(2) optionally applying the fixing agent from the

Fixing agent composition on the contact surface D, (3) Placing the Lotvorform with its contact surface C on the contact surface D optionally with the located between the contact surfaces C and D.

Fixer,

(4) melting the fixed solder preform to form molten solder,

(5) cooling the molten solder below its solidification temperature

Formation of a solder deposit with a free contact surface Y,

Contact surfaces Y and A,

(8) melting the solder deposit to form molten solder, and

The abovementioned six embodiments of the method according to the invention represent defined step sequences which comprise or consist of the respective successive steps (1) to (8) or (1) to (9). These eight or nine steps may be directly consecutive steps, i. without intermediate steps or at least without essential

Intermediate steps, ie without the essence of the method according to the invention changing intermediate steps. However, partial steps of the

Provisioning step (1) form an exception such that, as far as the further step sequence permits or even requires, it can take place or be completed at a suitable point in the method and thus bring the provisioning step (1) to a complete conclusion.

The present disclosure, in addition to the sandwich arrangements that can be produced by the method according to the invention, also includes arrangements which are known as

Intermediates of the method according to the invention can be obtained or occur. Such an arrangement obtainable as an intermediate in the first, third and fifth embodiment of the method according to the invention comprises an arrangement of a component with a contact surface A and one with this

Contact surface A connected solder deposit with a free contact surface X, which is provided with the fixing agent.

Another such as an intermediate in the first, third and fifth

Embodiment of the method according to the invention comprises an arrangement of a first component having a contact surface A and a second component having a contact surface D and one between the

Contact surfaces A and D arranged connected to the contact surface A.

Lotdepot, which is connected with its free contact surface X facing the contact surface D by means of the fixing agent. In other words, it is an unsoldered sandwich assembly of a component with a connected to its contact surface A solder deposit with a free contact surface X, which in turn is connected by means of the fixing with the contact surface D of the other component.

Another arrangement obtainable as an intermediate in the second, fourth and sixth embodiment of the method according to the invention comprises an arrangement of a component with a contact surface D and a solder depot connected to this contact surface D with a free contact surface Y, which is provided with the fixing means. Another such as an intermediate in the second, fourth and sixth

Contact surfaces A and D arranged connected to the contact surface D.

Lotdepot, which is connected with its free contact surface Y facing the contact surface A by means of the fixing agent. In other words, it is an unsoldered sandwich assembly of a device with a connected to its contact surface D solder depot with a free contact surface Y, the in turn is connected by means of the fixing means with the contact surface A of the other component.

Another arrangement obtainable as an intermediate in the third and fifth embodiment of the method according to the invention comprises an arrangement of a component having a contact surface A and a solder preform with discrete contact surfaces B and C with the fixing means between the contact surfaces A and B.

Another such as an intermediate in the fourth and sixth

Embodiment of the method according to the invention comprises an arrangement of a device with a contact surface D and a

Lotvorform with discrete contact surfaces B and C with the fixing between the contact surfaces C and D. Another such as an intermediate in the third to sixth

Embodiment of the inventive method available comprises a free component with a provided with the fixing contact surface A respectively a free component with a provided with the fixing agent

Contact area D.

Another such as an intermediate in the third to sixth

Embodiment of the method according to the invention comprises a free Lotvorform with discrete contact surfaces B and C, wherein the contact surfaces B and / or C are provided with the fixing agent.

In the method according to the invention, the contact surfaces X are arranged to D or Y facing A respectively brought into contact. In this case, the contact surfaces X and D and Y and A in each case form a common one with one another

Overlapping area. If the contact surfaces X and D or Y and A do not have the same dimensions or if the contact surfaces X and D or Y and A are not congruent with each other in the mutually facing arrangement, then the common overlapping surface of a partial surface corresponds to at least one of the contact surfaces forming it D and X respectively A and Y. Considering the facing arrangement and the

Contacting the contact surfaces A and B or C and D, the same applies analogously.

Herein is the contacting of contact surfaces with or without the

Fixative between the contact surfaces the speech. In this context, the term "contact" means a direct contact in the sense of a touch up to a contact in the sense of an approach to a negligible distance of, for example, <100 pm. The latter applies in particular in the case of a

Presence of the fixing agent between contact surfaces. To avoid misunderstandings, in the case of a cohesive solder connection between

Contact surfaces exists only an indirect connection between the

soldered respectively soldered contact surfaces, whereas a direct contact to the connecting solder. The contacting of contact surfaces with the fixing means between said contact surfaces means that the fixing agent has been applied from at least one of the two contact surfaces involved, which in the case of a solvent-containing fixative composition, as mentioned above, comprises removal of solvent prior to actual contacting. The contact surfaces of types A, B, C and D have only a small average

Surface roughness Ra (determined according to DIN EN ISO 25178-6: 2010-06)

for example in the range of 0.1 to 40 pm.

In general, the contact surfaces of the type A, B, C, D, X and Y are flat or substantially planar.

Herein, the term "fixing agent" or "as mentioned above

used composite fixative applied fixative ". This refers to the applied to a respective contact surface A, B, C, D, X and Y fixing in the state and under the conditions immediately before or facing each other arranging and contacting the contact surfaces of Lotvorform and device with the fixing between them or directly before or when fixing the solder deposit with the fixing between the contact surfaces A and Y respectively D and X. Said conditions For example, include the conditions prevailing in arranging and contacting in terms of temperature, air pressure and humidity respectively

Temperature and type of ambient atmosphere. Thus, it may be expedient to arrange and bring into contact at elevated, but in any case below the melting temperature of the solder lying temperature

perform. For example, this can be done with heated contact surfaces.

The fixing agent is composed of a compound as mentioned above

Fixing agent applied. The herein in connection with the application of fixative of a compound as mentioned above

Term fixative composition used on a contact surface

"Applying" may be followed by a thermal and / or photochemical during and / or subsequent to the actual application

Include treatment. In the case of a solvent-containing

Fixiermittelzusammensetzung includes the term "applying" in each case, a subsequent to the actual application subsequent removal of solvent,

in particular extensive to preferably complete removal of solvent, for example by drying, which by conventional means such as

For example, heating and / or pressure reduction can be assisted or effected. Extensive to complete solvent removal means

Removal of> 50 to 100 wt .-%, preferably> 80 to 100 wt .-% of

originally contained in the solvent-containing fixer composition solvent. The fixative composition consists, as already stated

0 to 97 wt .-% of at least one solvent selected from the group consisting of water and at <285 ° C boiling organic solvents,

3 to 100 wt .-% of at least one material M1 selected from the group consisting of (i) in the range of 30 to 180 ° C meltable thermoplastic organic polymers and (ii) in the range of 30 to 180 ° C fusible non-polymeric organic compounds without acid Groups,

0 to 20 wt .-% of at least one material M2 selected from the group consisting of (iii) in the range of 30 to 180 ° C non-meltable organic polymers and (iv) in the range of 30 to 180 ° C non-meltable non-polymers organic compounds without acidic groups and without boiling point or with a boiling point above 285 ° C, and

0 to 30 wt .-% of one or more inorganic solid fillers. Depending on their content of from 0 to 97% by weight of at least one solvent selected from the group consisting of water and organic solvents boiling at <285 ° C., the fixative composition may be a solvent-free, an aqueous, organic solvent-free one aqueous organic solvent-containing or non-aqueous

organic solvent-containing composition act.

Examples of solvent-free fixer compositions are, when applied, solid to sticky fixer compositions, for example in the form of film, strand, powder, droplet, flotmelt material, oily or resinous material.

Depending on the consistency of a relevant solvent-free

Fixer composition, the skilled person will select a method suitable for application to a contact area A, B, C, D, X and Y, respectively.

Examples of aqueous fixer compositions are aqueous from

organic solvent-free or aqueous organic solvent-containing fixative compositions. These may be solutions, suspensions or dispersions whose theological behavior can be in a wide range from the liquid to the pasty state. Accordingly, the aqueous fixative compositions can be applied to a variety of ways

Contact area A, B, C, D, X and Y are applied, for example, by jetting, dispensing, spraying, brushing, dabbing, dipping or printing, followed by drying for the purpose of largely to preferably completely removing the water and the optionally contained organic solvent. For non-aqueous organic solvent containing

Fixer compositions may be solutions, suspensions or dispersions, the rheological behavior of which may range widely from the liquid to the pasty state. Accordingly, non-aqueous organic solvents containing Fixing agent compositions are applied in different ways to a contact surface A, B, C, D, X and Y, for example, by jetting, dispensing,

Spraying, brushing, dabbing, dipping or printing, followed by drying for the purpose of substantially to preferably completely removing the organic solvent.

Preferred as the at least one material M1 are in the range of 30 to 180 ° C fusible thermoplastic organic polymers of the type (i), and including in particular partially or fully synthetic representatives. Preferably, this includes

at least one material M1 does not contain nonsynthetic organic polymers, i. no organic polymers of natural origin such as natural resins. Examples of natural resins are tree resins such as rosin. Substance consists of the

Range of 30 to 180 ° C meltable thermoplastic organic polymers no limitation. It may be, for example, vinyl copolymers,

(Meth) acrylic copolymers, polyesters, polyurethanes, polymer precursors of such aforementioned polymers and / or cellulose derivatives such as

Cellulose ethers and esters act. Particularly preferred are (meth) acrylic copolymers and cellulose derivatives such as methylcellulose or ethylcellulose. The meltable in the range of 30 to 180 ° C thermoplastic organic polymers may have acid groups corresponding to an acid number in the range of 0 to 50 mg KOH / g, preferably below 25 mg KOH / g; more preferably, they have no acidic groups and have no acid number. The determination of the acid number, for example the carboxyl number of organic polymers, is known to the person skilled in the art, for example the determination according to DIN EN ISO 2114.

Preferred examples of non-polymeric organic compounds which can be melted in the range from 30 to 180 ° C without acidic groups of type (ii) are lactams such as, for example, laurolactam; and fatty alcohols such as 1-dodecanol (lauryl alcohol), 1-tetradecanol (myristyl alcohol), 1-hexadecanol (cetyl alcohol), 1-heptadecanol (margaryl alcohol), 1-octadecanol (stearyl alcohol), 1-eicosanol (arachidyl alcohol), 1-dodosanol ( Behenyl alcohol), 1-tetracosanol

(Lignoceryl alcohol), 1-hexacosanol (ceryl alcohol), 1-octacosanol (montanyl alcohol), 1-triacontanol (melissyl alcohol). Further examples of non-polymeric organic compounds which can be melted in the range from 30 to 180 ° C. without acidic groups of type (ii) are corresponding individual constituents of mixtures of organic substances which can be melted in the range from 30 to 180 ° C., such as oils, fats, waxes, for example natural waxes for example, beeswax, paraffin waxes and Vaseline.

The fixer composition contains 0 to 20% by weight of at least one

Materials M2 selected from the group consisting of (iii) in the range of 30 to 180 ° C non-meltable organic polymers and (iv) in the range of 30 to 180 ° C non-meltable non-polymeric organic compounds without acidic groups and without boiling point or with a boiling point above 285 ° C. The organic polymers of the type (iii) are different from those of the type (i) and preferably have no acidic groups. For example, it may be non-thermoplastic or outside the range of 30 to 180 ° C

act meltable organic polymers. The non-polymeric organic

Compounds of type (iv) differ from those of type (ii);

for example, it may be outside the range of 30 to 180 ° C

fusible non-polymeric organic compounds without acidic groups; alternatively, they may be non-polymeric organic compounds having no acidic groups which can boil and be distilled above 285 ° C without decomposition or which have a decomposition point or range instead of a boiling point. The latter can not be distilled under normal conditions.

Representatives of material M2 may be, for example, additives such as wetting additives and rheology additives.

The fixer composition contains from 0 to 30% by weight of one or more inorganic solid fillers. Examples of inorganic solid fillers are silica and alumina.

The sum of the provided with the fixing surface portions of the free contact surface of the solder deposit a common overlap surface forming contact surface A or D is in the presence of one or more components of type (i) in at least one material M1 1500 pm ² to 50 area%, preferably 1500 miti ² to 20 area%, in particular 1500 miti ² to 10 area% of the common overlap area. In the sole presence of one or more constituents of the type (ii) in the at least one material M1 said sum is 1500 pm ² to 100 area%, preferably 1500 miti ² to 50 area%, in particular 1500 pm ² to 20 area% or even only 1500 pm ² to 10 area% of the common overlap area.

In variants of the third to sixth embodiments of the method according to the invention and in the presence of one or more constituents of the type (i) in the at least one material M1, it is such that the sum of the surface portions provided with the fixing means forms a common overlapping area when placing the solder preform Contact surfaces A and B and C and D respectively 1500 pm ² to 50 area%, preferably 1500 pm ² to 20 area%, in particular 1500 pm ² to 10 area% of the respective common

Overlap area is.

In variants of the third to sixth embodiments of the method according to the invention and in the sole presence of one or more constituents of the type (ii) in the at least one material M1, however, it is such that the sum of the surface portions provided with the fixing agent of the joint when placing the Lotvorform together Overlap surface forming contact surfaces A and B respectively C and D each 1500 pm ² to 100 area%, preferably 1500 pm ² to 50 area%, in particular 1500 pm ² to 20 area% or even only 1500 pm ² to 10 area% the respective common overlap area is.

The fixative can in all the above-mentioned cases as a single

contiguous surface or distributed as a plurality of separate surfaces, for example, as one or more surface elements,

for example, as points, lines, line or dot patterns. Individual or all surface elements may also have a respective one

Overlap area boundary line protrude, for example, such that the fixative composition is intentionally or unintentionally applied overlapping a respective Überlappungsflächenbegrenzungslinie. For example, a surface element may partially overlap the overlap surface boundary line cover and are partially within and partially outside of the overlap area. A partial or complete frame-like covering of the overlap area boundary line is also possible. Individual contiguous surface elements not touching the overlap area boundary line may have an area of, for example, 1500 pm ² to 10 area%, preferably 1500 pm ² to 5 area%, in particular 1500 pm ² to 2 area% of the respective common overlap area. That or the

Surface elements can protrude sufficiently far from the corresponding contact surface plane to allow a fixing connection to be connected contact surfaces. So can the one or the existing of the fixative

Surface elements have a thickness, for example, in the range of 1 to 100 μm, or preferably 1 to 50 μm, or more preferably 1 to 20 μm, or most preferably 1 to 10 μm; This is especially true for not or not completely melted fixative.

The applied fixing agent may differ in its composition qualitatively and / or quantitatively from that of the fixative composition. This may be the result, for example, of its application and / or removal of solvent or drying and / or thermal and / or photochemical treatment deliberately carried out as part of its application. In the case of a fixing agent applied from a solvent-containing fixative, its solvent content is reduced relative to that of the fixer composition by> 50 to 100% by weight, preferably by> 80 to 100% by weight. In other words, in comparison with the solvent-containing fixative composition, more than half, preferably more than 80,% by weight of the solvent originally contained in the solvent-containing fixative composition is removed in the applied fixative.

One in its composition of the aforementioned

Fixing agent composition different fixing agent, for example, from 0 to 10 wt .-% of at least one solvent selected from the group consisting of water and at <285 ° C boiling organic solvents,

65 to 100 wt .-% of at least one material M1 selected from the group consisting of (i) meltable in the range of 30 to 180 ° C thermoplastic organic polymers and (ii) in the range of 30 to 180 ° C fusible non-polymeric organic compounds without acidic groups,

0 to 25 wt .-% of at least one material M2 selected from the group consisting of (iii) in the range of 30 to 180 ° C non-meltable organic polymers and (iv) non-meltable in the range of 30 to 180 ° C non-polymeric organic compounds without acidic groups and without boiling point or with a boiling point above 285 ° C, and

0 to 35 wt .-% of one or more inorganic solid fillers. The fixing agent exhibits adhesion-promoting behavior between pads A and B, C and D, A and Y, and D and X, respectively, to be bonded. at least in the conditions prevailing when arranging and contacting the respective contact surfaces with the fixing agent therebetween, it behaves sticky and / or adhesion of the respective contact surfaces.

The aforementioned first and second embodiment of the invention

Each method comprises application of solder paste, for example by printing, jetting, dispensing or dipping. After applying the solder paste, the production of the solder deposit takes place. This involves melting the solder paste to form molten solder and then cooling the molten solder below it

Solidification temperature. The device with its provided with applied solder paste contact surface A and D is conveyed for the purpose of melting the solder paste in an oven with a lying above the melting temperature of the solder oven temperature. The

Storing time in the oven and the oven temperature are dimensioned so that a complete melting of the solder paste can take place. For example, the residence time in the oven in the range of 1 to 60 minutes at a furnace temperature, for example in the range of 150 to 500 ° C, in particular 170 to 350 ° C. The melting process can be carried out as a batch process or as a continuous process. The aforementioned third to sixth embodiment of the invention

Each method includes placing a Lotvorform, for example, placing the Lotvorform on a device or vice versa. The hanging up takes place in the sense of a mutually facing arrangement of

Contact surfaces A and B respectively C and D.

Placing the Lotvorform and making the solder deposits as well as

Downstream production of the still unsoldered sandwich arrangement can, for example, in the range of room temperature to below the

Melting temperature of the solder take place, for example, to 10 ° C below the melting temperature of the solder.

After placing the solder preform, the production of the solder deposit takes place. This involves melting the solder preform to form molten solder and then cooling the molten solder below it

Solidification temperature.

The assembly of component and Lotvorform optionally with the fixing agent between the contact surfaces A and B and C and D is for the purpose of melting the Lotvorform transported in an oven with a lying above the melting temperature of the solder furnace temperature. The length of stay in the oven and the

Furnace temperature are dimensioned so that a complete melting of Lotvorform can take place. For example, the residence time in the oven in the range of 1 to 60 minutes at a furnace temperature, for example in the range of 150 to 500 ° C, in particular 170 to 350 ° C. The melting process can be carried out as a batch process or as a continuous process.

It is not clarified in detail what happens during the melting process with the optionally present fixative.

After leaving the oven, the arrangement of component and cools

molten solder and the solder solidifies after falling below his

Solidification temperature to form the equipped with the solder deposit

Component. In the case of a device having a contact surface A has the Lotdepot a free contact surface X, in the case of a device with a

Contact surface D, the solder deposit has a free contact surface Y.

Common to the aforementioned six embodiments of the method according to the invention is the production of a still unsoldered sandwich arrangement of the two components with the solder deposit therebetween

Fixing agent between the contact surfaces A and Y respectively D and X, followed by the actual soldering to form the final soldered sandwich assembly. By arranging the contact surface Y or X with the fixing means located therebetween, the unsoldered sandwich arrangement comprising a component provided with a solder depot and a further component to be connected thereto are provided by the contact surface A and D respectively.

After formation of the still unsoldered sandwich assembly, the actual solder connection process takes place. This solder joining process involves melting the solder deposit to form molten solder and then cooling the molten solder below its solidification temperature to form a final soldered sandwich of the two components connected via their contact surfaces A and D and the solidified solder therebetween.

The sandwich assembly of the two components with the solder deposit therebetween with the fixing between the contact surfaces A and Y and D and X respectively is conveyed to melt the solder deposit in a furnace with a lying above the melting temperature of the solder furnace temperature. The residence time in the oven and the oven temperature are dimensioned so that a complete melting of the solder deposit can take place. For example, the residence time in the range of 1 to 60 minutes at a furnace temperature, for example in the range of 150 to 500 ° C, in particular 170 to 350 ° C. The melting process can be carried out as a batch process or as a continuous process. It is not clarified in detail what happens during the melting process or soldering process with the fixing agent.

After leaving the oven, the sandwich arrangement cools out of the two

Components and the molten solder from and the solder solidifies after

Below its solidification temperature to form the product of the inventive method, namely the finished sandwich assembly of the first component with the contact surface A, the second component with the contact surface D with the located between the contact surfaces A and D, the two components mechanically, electrically and thermally conductive solder joining ,

Examples

Example 1 (according to the invention):

A fixer composition consisting of 20% by weight DEGALAN® LP 63/11 (acrylic copolymer available from Evonik Industries AG, acid number 6 mg KOH / g, Mw 30,000) dissolved in 80% by weight a-terpineol was coated by means of a 20 μm thick

Template with a round opening and a diameter of 40 pm printed on a copper side of a DCB substrate (320 μm thick AhOs ceramic with 200 μm copper lamination on both sides). Subsequently, the fixative composition thus applied was dried for 20 minutes at 80 ° C in a convection oven. This gave a 2000 pm ² large and 3 pm thick Fixiermittelpunkt. Subsequently, a 10 mm × 10 mm × 0.1 mm solder preform (tin-silver alloy containing 3.5% by weight silver) was placed on this fixation center in a centric manner. This was done by means of a loading device Datacon 2200 evo, the DCB substrate before the actual loading to 130 ° C.

preheated and the solder preform with a force of 1 Newton on the

Fixing center was launched.

The assembly thus created was exposed in a soldering oven to a temperature profile of 6 minutes at 180 ° C and then for 3 minutes at 260 ° C. To

Removal from the oven was allowed to cool the assembly to room temperature. The solder preform had formed a solder deposit firmly connected to the copper side of the DCB. In a further step, the printing and drying of the

Fixing agent composition analogously as described above repeated on the outwardly facing side of the solder deposit. Then, a 10 mm × 10 mm × 0.18 mm IGBT was placed on the fixation center thus applied to the solder deposit under the same conditions and using the same

Placement equipment placed.

The thus-still unsoldered sandwich assembly was exposed in a soldering oven to a temperature profile of 6 minutes at 180 ° C and then 3 minutes at 260 ° C, the solder completely melted. After removal from the oven, the sandwich assembly was allowed to cool to room temperature.

After cooling, the thermal conductivity of the solder joint within the sandwich arrangement was determined to be 36 Wm ¹ K ¹ by means of the laser flash method (LFA 467 from Netzsch, Germany, Energieimpuls from the side of the IGBT).

Example 2 (according to the invention):

By way of derogation from Example 1, the fixing agent composition was printed in each case by means of a 20 pm thick stencil with four square openings of 9 mm ² , spaced apart from each other by 2 mm, as a 2-2 arrangement. This gave four each approximately 10 mm ² and 3 pm thick Fixiermittel- surface elements (total of about 40 area% coverage of the respective

Overlap area after placing the solder preform or after equipping with the IGBT).

The thermal conductivity determination gave a value of 22 Wm ¹ K ¹ .

Example 3 (comparison):

By way of derogation from Example 1, the fixative composition was printed in each case by means of a 20 pm thick stencil with four square openings of 13 mm ² , spaced apart from each other by 2 mm, as a 2-2 arrangement. This gave four each about 13.5 mm ² large and 3 pm thick Fixiermittel- surface elements (total of about 55 area% coverage of the respective Overlap area after placing the solder preform or after equipping with the IGBT).

The thermal conductivity determination gave a value of 15 Wm ¹ K ¹ .

Thermal conductivities> 20 Wm ¹ K ¹ are satisfactory results.

Claims

claims

1. A method for producing a sandwich assembly of a first component having a contact surface A, a second component with a

Contact surface D and located between the contact surfaces A and D Lot, wherein the solder by melting a at the contact surface A or D with one of the components connected solder deposits and subsequent cooling of the

molten solder is made below its solidification temperature,

Contact surface of the solder deposit is applied,

wherein the fixer composition is

0 to 30 wt .-% of one or more inorganic solid fillers, wherein the sum of the provided with the fixing surface portions of the free contact surface of the solder deposit a common overlap surface forming contact surface A or D in the presence of one or more components (i) in the at least a material M1 is 1500 pm ² to 50 area% of the common overlap area, whereas said sum in the sole presence of one or more constituents (ii) in the at least one material M1 is 1500 pm ² to 100 area% of the common overlap area.

2. The method according to claim 1, comprising the successive steps: (1) providing a first device having a contact surface A, a second device having a contact surface D, the fixer composition and a solder paste,

(2) applying the solder paste to the contact surface A,

(3) melting the applied solder paste to form molten solder,

(4) cooling the molten solder below its solidification temperature to form a solder deposit having a free contact area X,

(5) applying the fixing agent from the fixer composition to the contact surfaces X and / or D,

Contact surfaces X and D,

(7) melting the solder deposit to form molten solder, and

3. The method according to claim 1, comprising the successive steps:

(1) providing a first device having a contact surface A, a second device having a contact surface D, the fixer composition and a solder paste,

(2) applying the solder paste to the contact surface D,

(3) melting the applied solder paste to form molten solder,

(5) applying the fixing agent from the fixer composition to the contact surfaces Y and / or A,

Contact surfaces Y and A,

(7) melting the solder deposit to form molten solder, and

4. The method of claim 1, comprising the successive steps:

(1) providing a first device having a contact surface A, a second device having a contact surface D, the fixer composition and a Lotvorform with discrete each not provided with fixing agent

Contact surfaces B and C,

(2) optionally applying the fixing agent from the

Fixing agent composition on the contact surfaces A and / or B,

(4) melting the fixed solder preform to form molten solder,

(6) applying the fixing agent from the fixer composition to the contact surface X and / or the contact surface D,

Contact surfaces X and D,

(8) melting the solder deposit to form molten solder, and

(9) cooling the molten solder below its solidification temperature

Forming a sandwich arrangement of the two components connected via their contact surfaces A and D and the solidified solder therebetween.

5. The method of claim 1, comprising the successive steps: (1) providing a first device having a contact surface A, a second one

Component having a contact surface D, the fixer composition and a Lotvorform with discrete each not provided with fixing

Contact surfaces B and C,

(2) optionally applying the fixing agent from the

Fixing agent composition on the contact surfaces C and / or D,

(4) melting the fixed solder preform to form molten solder, (5) cooling the molten solder below its solidification temperature to form a solder deposit having a free contact area Y,

Contact surfaces Y and A,

(8) melting the solder deposit to form molten solder, and

6. The method of claim 1, comprising the successive steps:

(1) providing a first device having a contact surface A, a second device having a contact surface D, the fixer composition, and a solder preform having discrete contact surfaces B and C, one or both of which are provided with the fixing agent applied from the fixer composition,

(2) optionally applying the fixing agent from the

Fixing agent composition on the contact surface A,

Fixer,

(4) melting the fixed solder preform to form molten solder,

Contact surfaces X and D,

(8) melting the solder deposit to form molten solder, and

A method according to claim 1, comprising the successive steps:

(2) optionally applying the fixing agent from the

Fixing agent composition on the contact surface D,

(3) Placing the Lotvorform with its contact surface C on the contact surface D optionally with the located between the contact surfaces C and D.

Fixer,

(4) melting the fixed solder preform to form molten solder,

(5) cooling the molten solder below its solidification temperature to form a solder deposit having a free contact area Y,

(6) applying the fixing agent from the fixer composition to the

Contact surface Y and / or the contact surface A,

Contact surfaces Y and A,

(8) melting the solder deposit to form molten solder, and

(9) cooling the molten solder below its solidification temperature to form a sandwich of the two components joined via their contact surfaces A and D and the solidified solder therebetween. 8. An intermediate product of the process according to any one of claims 2, 4 or 6 in

Form of an assembly of a component having a contact surface A and connected to this contact surface A solder deposit with a free contact surface X, which is provided with the fixing means, or according to one of claims 3, 5 or 7 in the form of an assembly of a component with a Contact surface D and a connected to this contact surface D solder depot with a free contact surface Y, which is provided with the fixing agent.