Method for producing a sandwhich arrangement

Abstract

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 a solder located between said contact surfaces A and D,

wherein the solder is produced by melting a solder deposit that is arranged between the two components and connected at the contact surface A or D to one of the components, followed by cooling of the molten solder to below its solidification temperature,
wherein the solder deposit is produced previously by melting a solder preform that is fixed to the relevant contact surface A or D by means of an applied fixing agent from a fixing agent composition, followed by cooling of the molten solder to below its solidification temperature, and
wherein the solder deposit is arranged with its free contact surface facing the corresponding contact surface D or A of the as of yet unconnected component, wherein the fixing agent composition consists of
0 to 97 wt. % (weight %) of at least one solvent selected from the group consisting of water and organic solvents boiling at 285 C.,
3 to 100 wt. % of at least one M1 material selected from the group consisting of (i) thermoplastic organic polymers that are meltable between 30 and 180 C. and (ii) non-polymeric organic compounds with no acidic groups that are meltable between 30 and 180 C.,
0 to 20 wt. % of at least one M2 material selected from the group consisting of (iii) organic polymers that are not meltable between 30 and 180 C. and (iv) non-polymeric organic compounds with no acidic groups that are not meltable between 30 and 180 C. and not having a boiling point or having a boiling point above 285 C., and
0 to 30 wt. % of one or more inorganic solid fillers, and
wherein the sum of the surface sections that are provided with the fixing agent, of the contact surfaces A and B or C and D that upon placing the solder preform together form a common overlapping area, in the presence of one or more components (i) in the at least one M1 material is 1500 m.sup.2 to 50 area % of the common overlapping area, while, when only one or more of the components (ii) are present in the at least one M1 material said sum is 1500 m.sup.2 to 100 area % of the common overlapping area.

Claims

1. A method for producing a sandwich arrangement from of 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 produced by melting a solder deposit that is arranged between the two components and connected to one of the components at the contact surface A or D, followed by cooling the molten solder to below its solidification temperature, wherein the solder deposit is produced previously by melting a solder preform that is fixed to the relevant contact surface A or D by means of an applied fixing agent from a fixing agent composition, followed by cooling the molten solder to below its solidification temperature, and wherein the solder deposit is arranged by the free contact surface thereof facing the corresponding contact surface D or A of the as of yet unconnected component, wherein the fixing agent composition consists of 0 to 97 wt. % (weight %) of at least one solvent selected from the group consisting of water and organic solvents boiling at 285 C., 3 to 100 wt. % of at least one M1 material selected from the group consisting of (i) thermoplastic organic polymers that are meltable between 30 and 180 C. and (ii) non-polymeric organic compounds with no acidic groups that are meltable between 30 and 180 C., 0 to 20 wt. % of at least one M2 material selected from the group consisting of (iii) organic polymers that are not meltable between 30 and 180 C. and (iv) non-polymeric organic compounds with no acidic groups that are not meltable between 30 and 180 C. and do not have a boiling point or that have a boiling point above 285 C., and 0 to 30 wt. % of one or more inorganic solid fillers, and wherein the sum of the surface sections that are provided with the fixing agent, of the contact surfaces A and B or C and D, that upon placing the solder preform together form a common overlapping area, in the presence of one or more components (i) in the at least one M1 material is 1500 m.sup.2 to 50 area % of the common overlapping area, while, when only one or more of the components (ii) are present in the at least one M1 material said sum is 1500 m.sup.2 to 100 area % of the common overlapping area.

2. The method according to claim 1, comprising the following sequential steps: (1) providing a first component having a contact surface A, a second component having a contact surface D, the fixing agent composition, as well as a solder preform with discrete contact surfaces B and C not provided with fixing agent, (2) applying the fixing agent from the fixing agent composition to the contact surfaces A and/or B, (3) placing the solder preform by its contact surface B onto the contact surface A with the fixing agent between contact surfaces A and B, (4) melting the fixed solder preform, thereby forming molten solder, (5) cooling the molten solder to below its solidification temperature, thereby forming a solder deposit having a free contact surface X, (6) optionally applying the fixing agent from the fixing agent composition to the contact surfaces D and/or X, (7) producing a sandwich arrangement from the two components with the solder deposit located between them by arranging the contact surfaces X and D facing each other, with the fixing agent optionally located between them, (8) melting the solder deposit, thereby forming molten solder, and (9) cooling the molten solder to below its solidification temperature, thereby forming a sandwich arrangement from the two components that are connected via their contact surfaces A and D and the solidified solder located between them.

3. The method according to claim 1, comprising the following sequential steps: (1) providing a first component having a contact surface A, a second component having a contact surface D, the fixing agent composition, as well as a solder preform with discrete contact surfaces B and C not provided with fixing agent, (2) applying the fixing agent from the fixing agent composition to the contact surfaces C and/or D, (3) placing the solder preform by its contact surface C onto the contact surface D with the fixing agent between contact surfaces A and B, (4) melting the fixed solder preform, thereby forming molten solder, (5) cooling the molten solder to below its solidification temperature, thereby forming a solder deposit having a free contact surface Y, (6) optionally applying the fixing agent from the fixing agent composition to the contact surfaces A and/or Y, (7) producing a sandwich arrangement from the two components with the solder deposit located between them by arranging the contact surfaces Y and A facing each other, with the fixing agent optionally located between them, (8) melting the solder deposit, thereby forming molten solder, and (9) cooling the molten solder to below its solidification temperature, thereby forming a sandwich arrangement from the two components that are connected via their contact surfaces A and D and the solidified solder located between them.

4. The method according to claim 1, comprising the following sequential steps: (1) providing a first component having a contact surface A, a second component having a contact surface D, a solder preform having discrete contact surfaces B and C, wherein only contact surface B is provided with the fixing agent, as well as, optionally, the fixing agent composition, (2) optionally applying the fixing agent from the fixing agent composition to the contact surface A, (3) placing the solder preform by its contact surface B onto the contact surface A with the fixing agent between contact surfaces A and B, (4) melting the fixed solder preform, thereby forming molten solder, (5) cooling the molten solder to below its solidification temperature, thereby forming a solder deposit having a free contact surface X, (6) optionally applying the fixing agent from the fixing agent composition to the contact surfaces D and/or X, (7) producing a sandwich arrangement from the two components with the solder deposit located between them by arranging the contact surfaces X and D facing each other, with the fixing agent optionally located between them, (8) melting the solder deposit, thereby forming molten solder, and (9) cooling the molten solder to below its solidification temperature, thereby forming a sandwich arrangement from the two components that are connected via their contact surfaces A and D and the solidified solder located between them.

5. The method according to claim 1, comprising the following sequential steps: (1) providing a first component having a contact surface A, a second component having a contact surface D, a solder preform having discrete contact surfaces B and C, wherein only contact surface C is provided with the fixing agent, as well as, optionally, the fixing agent composition, (2) optionally applying the fixing agent from the fixing agent composition to the contact surface D, (3) placing the solder preform by its contact surface C onto the contact surface D with the fixing agent between contact surfaces C and D, (4) melting the fixed solder preform, thereby forming molten solder, (5) cooling the molten solder to below its solidification temperature, thereby forming a solder deposit having a free contact surface Y, (6) optionally applying the fixing agent from the fixing agent composition to the contact surfaces A and/or Y, (7) producing a sandwich arrangement from the two components with the solder deposit located between them by arranging the contact surfaces Y and A facing each other, with the fixing agent optionally located between them, (8) melting the solder deposit, thereby forming molten solder, and (9) cooling the molten solder to below its solidification temperature, thereby forming a sandwich arrangement from the two components that are connected via their contact surfaces A and D and the solidified solder located between them.

6. An intermediate product of the method according to claim 2 in the form of an arrangement consisting of a first component having a contact surface A and a second component having a contact surface D and a solder deposit that is arranged between said contact surfaces A and D and connected to contact surface A, which is connected, facing the contact surface D, by its free surface X, by means of the applied fixing agent from the fixing agent composition, or according to claim 3 or 5 in the form of an arrangement consisting of a first component having a contact surface A and a second component having a contact surface D and a solder deposit that is arranged between said contact surfaces A and D and connected to contact surface D, which is connected, facing the contact surface A, by its free surface Y, by means of the applied fixing agent from the fixing agent composition.

7. An intermediate product of the method according to claim 4 in the form of an arrangement consisting of a first component having a contact surface A and a second component having a contact surface D and a solder deposit that is arranged between said contact surfaces A and D and connected to contact surface A, which is connected, facing the contact surface D, by its free surface X, by means of the applied fixing agent from the fixing agent composition, or according to claim 3 or 5 in the form of an arrangement consisting of a first component having a contact surface A and a second component having a contact surface D and a solder deposit that is arranged between said contact surfaces A and D and connected to contact surface D, which is connected, facing the contact surface A, by its free surface Y, by means of the applied fixing agent from the fixing agent composition.

Description

EXAMPLES

Example 1 (According to the Invention)

[0076] A fixing agent composition consisting of 20 wt. % DEGALAN LP 63/11 (acryl copolymer available from Evonik Industries AG, acid number 6 mg KOH/g, MW 30,000) dissolved in 80 wt. % -terpineol was printed using a mask, 20 m thick with a round opening and a diameter of 40 m onto a copper side of a DCB substrate (320 m thickness Al.sub.2O.sub.3 ceramic with bilateral 200 m copper lamination). The fixing agent composition applied in this manner was then dried for 20 min at 80 C. in a convection drying oven. A fixing center measuring 2000 m.sup.2 and 3 m thick was obtained. A solder preform measuring 10 mm10 mm0.1 mm (tin-silver alloy having a 3.5 wt. % silver content) was placed, machine-centered, on said fixing center. This was done with a Datacon 2200 evo placement device, wherein the DCB substrate was preheated to 130 C. prior to the actual placement, and the solder preform was placed on the fixing center applying a force of 1 Newton.

[0077] The arrangement created in this manner was exposed, inside a soldering furnace, to a temperature profile of 6 minutes at 180 C. followed by 3 minutes at 260 C. After removing it from the furnace, the arrangement was allowed to cool to room temperature. A solder deposit had formed from the solder preform solidly connected to the copper side of the DCB.

[0078] In a further step, the printing and drying of the fixing agent composition was repeated, analogous to the process described above, on the outward facing side of the solder deposit. Subsequently, an IGBT measuring 10 mm10 mm0.18 mm was placed onto the fixing center, which had been applied to the solder deposit in this manner, under the same conditions and using the same placement apparatus.

[0079] The sandwich arrangement created in this manner and as of yet unsoldered, was exposed, inside a soldering furnace, to a temperature profile of 6 minutes at 180 C. followed by 3 minutes at 260 C. resulting in the complete melting of the solder. After removing it from the furnace, the sandwich arrangement was allowed to cool to room temperature.

[0080] After cooling, the thermal conductivity of the soldered connection inside the sandwich arrangement was determined by means of a laser flash analysis (instrument LFA 467 from Netzsch, Germany, energy pulse coming from the IGBT side) to be 36 Wm.sup.1K.sup.1.

Example 2 (According to the Invention)

[0081] Contrary to Example 1, the fixing agent composition was printed by means of a mask, 20 m thick with four square openings each measuring 9 mm.sup.2 in a 2.Math.2 arrangement spaced at 2 mm each. Four fixing agent area elements measuring about 10 mm.sup.2 in size and 3 m thickness were obtained (in total about 40 area % coverage of the respective overlapping area after placement of the solder preform or after placement with the IGBT).

[0082] The thermal conductivity determination resulted in a value of 22 Wm.sup.1K.sup.1.

Example 3 (Comparison)

[0083] Contrary to Example 1, the fixing agent composition was printed by means of a mask, 20 m thick with four square openings each measuring 13 mm.sup.2 in a 2.Math.2 arrangement spaced at 2 mm each. Four fixing agent area elements measuring about 13.5 mm.sup.2 in size and 3 m thickness were obtained (in total about 55 area % coverage of the respective overlapping area after placement of the solder preform or after placement with the IGBT).

[0084] The thermal conductivity determination resulted in a value of 15 Wm.sup.1K.sup.1.

[0085] A thermal conductivity of >20 Wm.sup.1K.sup.1 is a satisfactory result.