Substrate structure having a surface structure

Abstract

The present invention relates to a method for manufacturing substrate components and electronic assemblies. The substrate structure comprises (a) a bonding substrate having an upper surface and a lower surface, and (b) a contact layer having contact means, the contact layer being connected planarly to the lower surface of the bonding substrate in at least a region, and the lower surface of the bonding substrate having (i) an arithmetic mean roughness value R(1) along at least one section S1 a (ii) having an arithmetic mean roughness value R(2) along at least one section S2 a It has, and at least one section S2 extends perpendicularly to at least one section S1, and the arithmetic mean roughness value R(1) a R(2) a The ratio Q is in the range of 1.70 to 10.00.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing substrate components and electronic assemblies.

[0002] In the field of power electronics, electronic components, particularly semiconductors, are often mounted on base substrates, especially metal-ceramic substrates or lead frames, in order to manufacture electronic assemblies.

[0003] The area of ​​the electronic component that must be electrically in contact with the unmounted area of ​​the base substrate is located on the upper surface of the electronic component opposite the base substrate. This contact is usually made using a bonding wire, with one end of the bonding wire integrally bonded to the area on the upper surface of the electronic component and the other end of the bonding wire integrally bonded to the unmounted area of ​​the base substrate. The bonding wire made of aluminum may be integrally bonded to the metal of the base substrate, particularly copper. The bonding wire made of aluminum may be located on the upper surface of the electronic component and integrally bonded to the electronic component via a layer containing, for example, metal, usually silver. However, bonding wires made of aluminum have the disadvantage of low conductivity. Furthermore, it has been found that electrical contact between the electronic component and the base substrate via an aluminum bonding wire has insufficient reliability and reduced functionality.

[0004] For this reason, aluminum bonding wires need to be replaced with copper bonding wires. Copper has a much higher conductivity than aluminum. Furthermore, copper bonding wires can be integrally bonded to the metal of the base substrate, especially copper, and thus provide a particularly secure connection. However, copper bonding wires cannot be easily bonded to the upper surface of electronic components while integrally bonded.

[0005] In the prior art, it has been proposed that bonding wires made of copper are not directly connected to the upper surface of electronic components. Rather, a substrate structure having a bonding substrate and a contact layer is provided. The bonding substrate, usually a metal foil, has an upper surface and a lower surface, and the lower surface of the bonding substrate is planarly bonded to a contact layer, usually a pre-dried sintered paste. The bonding substrate of the substrate structure is ultimately integrally bonded to the upper surface of the electronic component via the contact layer, so that the upper surface of the bonding substrate is available for integrally bonded connection with copper bonding wires.

[0006] In order to reliably connect bonding wires to the upper surface of electronic components via a substrate structure, it is necessary that the bonding substrate be stably and integrally bonded to the upper surface of the electronic components via a contact layer, thereby enabling connection.

[0007] Therefore, a substrate structure is needed that can connect the bonding substrate to the upper surface of the electronic component via a contact layer in a particularly stable and integral manner.

[0008] Therefore, an object of the present invention is preferably to provide a substrate structure that enables a stable and integrally bonded connection between a bonding substrate and the upper surface of an electronic component via a contact layer.

[0009] This objective is achieved by the substrate configuration described in claim 1.

[0010] Therefore, the present invention is a substrate structure, (a) A bonding substrate having an upper surface and a lower surface, (b) A contact layer comprising contact means, the contact layer being connected planar to the lower surface of the bonding substrate in at least a region, The underside of the bonding substrate is (i) Arithmetic mean roughness value R(1) along at least one section S1 a It has, (ii) Arithmetic mean roughness value R(2) along at least one section S2 a It has, and at least one section S2 extends perpendicularly to at least one section S1, Arithmetic mean roughness value R(1) a R(2) a The present invention provides a substrate structure in which the ratio Q is in the range of 1.70 to 10.00.

[0011] Furthermore, the present invention provides a method for manufacturing an electronic assembly.

[0012] This invention relates to a substrate structure.

[0013] Electrical contact between the upper surface of an electronic component and an unmounted area of ​​the base substrate can preferably be prepared using a substrate structure. For this purpose, the bonding substrate is connected to the upper surface of the electronic component via a contact layer. In this case, the bonding substrate provides a surface suitable for forming a reliable, integrally bonded connection to one end of a bonding wire, particularly a copper bonding wire. The other end of the bonding wire can be connected to an unmounted area of ​​the base substrate, resulting in electrical contact between the upper surface of the electronic component and the unmounted area of ​​the base substrate via the bonding substrate and bonding wire. Therefore, the upper surface of the substrate structure is connectable to the bonding wire. Preferably, the substrate structure does not have a layer of insulating material, particularly a ceramic layer. Particularly preferably, the substrate structure does not have an insulating material, particularly a ceramic.

[0014] The substrate structure includes a bonding substrate.

[0015] The bonding substrate comprises an upper surface and a lower surface. Therefore, the lower surface of the bonding substrate is preferably the surface of the bonding substrate having the maximum surface area that is planarly connected to the contact layer in at least a region. Therefore, the upper surface of the bonding substrate is preferably the surface of the bonding substrate opposite to the contact layer. Therefore, the upper surface of the bonding substrate is opposite to the lower surface of the bonding substrate. The bonding substrate preferably has a thickness in the range of 5 to 500 μm, particularly preferably in the range of 10 to 450 μm, and very particularly preferably in the range of 20 to 400 μm.

[0016] According to a preferred embodiment, the bonding substrate comprises a metal foil. Particularly very preferably, the bonding substrate is a metal foil.

[0017] The metal foil preferably contains at least one element selected from the group consisting of metals and metal alloys. In a further preferred embodiment, the metal foil contains at least one element selected from the group consisting of copper and copper alloys. In a particularly preferred embodiment, the metal foil contains copper. Here, the copper alloy may preferably be an alloy of copper with at least one further metal selected from the group consisting of nickel, tin, iron, silver, tungsten, and molybdenum.

[0018] According to a preferred embodiment, the metal foil comprises a body. The term “body” is preferably understood herein to mean an uncoated metal foil. The body preferably comprises at least one element selected from the group consisting of metals and metal alloys. According to a further preferred embodiment, the body comprises at least one element selected from the group consisting of copper and copper alloys. According to a particularly preferred embodiment, the body comprises copper. Here, the copper alloy may preferably be an alloy of copper with at least one further metal selected from the group consisting of nickel, tin, iron, silver, tungsten, and molybdenum.

[0019] In a particularly preferred embodiment, the metal foil is formed from the body. Therefore, according to this embodiment, the bonding substrate may be an uncoated copper foil. In this particularly preferred embodiment, the lower surface of the bonding substrate is formed from the metal foil, and the upper surface of the bonding substrate is formed from the metal foil. Therefore, the lower surface of the bonding substrate is formed from the body, and the upper surface of the bonding substrate is formed from the body.

[0020] In a particularly preferred embodiment, the metal foil comprises a body and a coating. Here, the coating is preferably disposed on the body. The coating preferably contains a precious metal. The precious metal is preferably selected from the group consisting of gold, silver, and palladium. The coating preferably comprises at least one first layer containing the precious metal, the first layer containing the precious metal being planarly connected to the contact layer in at least one area. The first layer can be formed from a precious metal or a precious metal alloy. The precious metal alloy is preferably an alloy containing at least one precious metal and at least one non-precious metal. The non-precious metal of the precious metal alloy is preferably nickel. The precious metal alloy is preferably selected from the group consisting of nickel-gold alloys, nickel-silver alloys, and nickel-palladium-gold alloys. In a preferred embodiment, the coating comprises at least one further layer. The at least one further layer is preferably planarly connected to the first layer. The at least one further layer is preferably not planarly connected to the contact layer. According to a preferred embodiment, at least one further layer comprises a precious metal or a non-precious metal. The non-precious metal is preferably nickel. The at least one further layer can be formed from a precious metal, a precious metal alloy, or a non-precious metal alloy (an alloy that does not contain a precious metal). The precious metal alloy is preferably an alloy containing at least one precious metal and at least one non-precious metal. According to a particularly preferred embodiment, the coating comprises a first layer containing gold, a second layer containing palladium, and a third layer containing nickel, in particular a first layer of gold, a second layer of palladium, and a third layer of nickel. In this case, the third layer is preferably planarly connected to the contact layer in at least a region, the second layer is planarly connected to the third layer and the first layer in at least a region, and the first layer is planarly connected to the second layer and the body in at least a region. In a particularly preferred embodiment, the first layer has a thickness in the range of 10 to 150 nm, the second layer has a thickness in the range of 50 to 200 nm, and the third layer has a thickness in the range of 1 to 5 μm. The metal foil coating is preferably achieved by electroplating or chemical deposition.According to this embodiment, the lower surface of the bonding substrate is formed by a coating. In this case, the lower surface of the bonding substrate is preferably formed by a coating, and the upper surface of the bonding substrate is formed by the main body.

[0021] Therefore, the bonding substrate preferably comprises a metal foil having a body on which a coating can be placed, and the lower surface of the bonding substrate is formed by (i) the body if no coating is placed on the body, and by (ii) the coating if a coating is placed on the body.

[0022] In a further preferred embodiment, the bonding substrate is not integrally bonded and connected to an insulating material, and in particular not integrally bonded and connected to a ceramic material.

[0023] In a further preferred embodiment, the bonding substrate has at least one through-opening extending from the top surface to the bottom surface. The through-opening is understood to mean a recess in the bonding substrate material that preferably extends from a first opening on the top surface of the bonding substrate to a second opening on the bottom surface of the bonding substrate. The openings can have different sizes and shapes. It may be preferable for the bonding substrate to have a plurality of through-openings. The through-openings may be, for example, cylindrical, circular, rectangular, oval, elliptical, or rectangular with rounded corners. The presence of through-openings may be particularly advantageous when the substrate structure comprises a temporary fixative layer containing a temporary fixative. In this case, components or residues of the temporary fixative can be liquefied during the application of temperature or pressure, such as during a sintering process, and absorbed into the through-openings by the capillary effect caused by the through-openings, thereby preventing uncontrolled leakage of some or all of the temporary fixative.

[0024] In yet another embodiment, the bonding substrate has no recesses or only slight recesses on the upper surface of the metal foil, and in particular, it has no recesses or only slight recesses extending from the upper surface to the lower surface of the metal foil. Preferably, the proportion of recesses on the upper surface of the metal foil is less than 10%, more preferably less than 5%, particularly preferably less than 1%, very particularly preferably less than 0.1%, and particularly less than 0.01%, relative to the total area of ​​the upper surface of the metal foil. Particularly preferably, the proportion of recesses on the upper surface of the metal foil extending from the upper surface to the lower surface is less than 10%, more preferably less than 5%, particularly preferably less than 1%, very particularly preferably less than 0.1%, and particularly less than 0.01%, relative to the total area of ​​the upper surface of the metal foil. The total area of ​​the upper surface of the metal foil is preferably understood to mean the surface of the upper surface of the metal foil occupied by the metal and recesses.

[0025] In a further preferred embodiment, the upper surface of the substrate structure is formed by a bonding substrate.

[0026] The substrate structure has a contact layer.

[0027] The contact layer is a layer that is planarly connected to the lower surface of the bonding substrate, at least in a given area.

[0028] In a preferred embodiment, the contact layer is preferably connected planarly to the lower surface of the bonding substrate such that the contact layer covers at least 75%, more preferably at least 90%, particularly preferably at least 95%, very particularly preferably at least 98%, and particularly especially 100% of the area occupied by the lower surface of the bonding substrate.

[0029] The contact layer preferably has a thickness in the range of 5 to 500 μm, particularly preferably in the range of 5 to 100 μm, and very particularly preferably in the range of 10 to 50 μm.

[0030] The contact layer comprises contact means. The contact means may preferably enter into connections integrally bonded with electronic components, particularly an optional metallized upper surface of the electronic components.

[0031] According to a preferred embodiment, the contact means includes at least one element selected from the group consisting of sintered materials, soldering materials, and adhesives.

[0032] The sintered material is preferably selected from the group consisting of sintered paste, sintered film, and sintered preform. The sintered material preferably contains at least one element selected from the group consisting of gold, silver, and copper. In a particularly preferred embodiment, the sintered material contains silver.

[0033] According to a preferred embodiment, the sintered material comprises a sintered paste. The sintered paste is preferably a sintered paste conventional in the art. The sintered paste preferably comprises at least one element selected from the group consisting of silver and copper, and an organic compound. It may be preferable that at least one element selected from the group consisting of silver and copper, particularly preferably silver, be present in the sintered paste in the form of particles. The particles can take any shape and therefore can exist, for example, as spherical particles, flakes, or irregularly shaped particles. The organic compound is preferably selected from the group consisting of dispersants, binders, fatty acids, and mixtures thereof. The dispersant can be selected from dispersants conventional in the art. An exemplary dispersant is terpineol. The binder can be selected from polymers conventional in the art. Examples include cellulose derivatives, such as methylcellulose, ethylcellulose, ethylmethylcellulose, carboxycellulose, and hydroxypropylcellulose. The fatty acid can be selected from fatty acids conventional in the art. The fatty acid is preferably selected from the group consisting of caprylic acid (octanoic acid), capric acid (decanoic acid), lauric acid (dodecanoic acid), myristic acid (tetradecanoic acid), palmitic acid (hexadecanoic acid), margaric acid (heptadecanoic acid), stearic acid (octadecanoic acid), arachidic acid (eicosanoic acid / eicosanic acid), behenic acid (docosanoic acid), and lignoceric acid (tetracosanoic acid). The sintered paste is preferably pre-dried. Pre-drying can be used to remove at least partially volatile components contained in the sintered paste, such as organic compounds. Pre-drying can be carried out, for example, at a temperature in the range of 80 to 150°C for, for example, 2 to 30 minutes.

[0034] In a further preferred embodiment, the sintered material includes a sintered film. Preferably, the sintered film is a conventional sintered film in the art, such as that disclosed in European Patent Application Publication No. 3154729(A1). Thus, the sintered film may have a sintered paste comprising, for example, metal particles (particularly silver particles) and a binder that is pre-dried and present on a carrier substrate. The sintered film may have a thickness in the range of, for example, 5 to 300 μm.

[0035] In a further preferred embodiment, the sintered material includes a sintered preform. Preferably, the sintered preform is a conventional sintered preform, such as that disclosed in European Patent Application Publication No. 2428293(A2).

[0036] In a further preferred embodiment, the solder material comprises at least one solder paste. The solder paste is preferably a solder paste commonly used in the art. The solder paste preferably comprises a solder alloy and a flux. The solder alloy preferably comprises, as a principal element (the element having the largest weight percentage), at least one further element selected from the group consisting of tin, particularly preferably copper and silver, and very preferably at least one further element selected from the group consisting of bismuth, antimony, indium, germanium, cobalt, iron and nickel. The flux is preferably a flux commonly used in the art, particularly preferably an organic flux.

[0037] In a further preferred embodiment, the adhesive comprises a conductive adhesive. The conductive adhesive is preferably a conductive adhesive commonly used in the art. The conductive adhesive preferably comprises silver particles and an epoxy resin and preferably cures at a temperature in the range of 120°C to 200°C.

[0038] According to a preferred embodiment, the substrate structure includes a temporary fixing layer.

[0039] The temporary fixing layer is preferably a layer connected to at least one further surface. The temporary fixing layer may be, for example, a continuous layer or an interrupted layer. The dimensions of the continuous layer are further limited. Therefore, the continuous layer may also include a point layer. In the case of a continuous layer, the temporary fixing layer may be connected planar to at least one further surface. In the case of an interrupted layer, the temporary fixing layer may include a plurality of portions that do not contact each other and are connected planar to at least one further surface. The at least one further surface is preferably the surface of a contact layer or the surface of the bonding substrate. According to a preferred embodiment, the temporary fixing layer is a layer connected to (i) the underside of the bonding substrate, (ii) the surface of a contact layer opposite to the bonding substrate, or (iii) the underside of the bonding substrate and the surface of a contact layer opposite to the bonding substrate. When the temporary fixing layer is connected to the underside of the bonding substrate, the contact layer is preferably connected planar to the underside of the bonding substrate, and the temporary fixing layer is connected to a region of the underside of the bonding substrate that is not connected planar to the contact layer. In this case, the contact layer and the temporary fixing layer are each connected to the lower surface of the bonding substrate and are preferably arranged adjacent to each other.

[0040] According to a preferred embodiment, the temporary fixing layer is formed as a continuous layer and is planarly connected to the contact layer opposite the bonding substrate such that at least 20%, more preferably at least 50%, particularly preferably at least 70%, very particularly preferably at least 98%, and especially particularly 100% of the surface area of ​​the contact layer opposite the bonding substrate is in contact with the temporary fixing layer.

[0041] In a further preferred embodiment, the temporary fixing layer is formed as a dotted continuous layer and is in contact with the surface of the contact layer opposite to the bonding substrate and / or the lower surface of the bonding substrate.

[0042] In a further preferred embodiment, the temporary fixing layer is formed as an interruption layer comprising a plurality of portions that do not contact each other but contact the surface of the contact layer opposite to the bonding substrate and / or the underside of the bonding substrate.

[0043] The temporary fixing layer preferably comprises a temporary fixing agent. The temporary fixing agent can function to temporarily fix the substrate structure on the electronic component so that the structure, which includes the substrate structure and the electronic component, has improved transportability, for example, at the site of further processing. Preferably, the temporary fixing agent is a temporary or peelable fixing agent that enables the substrate structure to be fixed to the electronic component at least temporarily. Suitable temporary fixing agents are described, for example, in European Patent Application Publication No. 3940758.

[0044] Therefore, the temporary fixative preferably comprises at least one compound selected from the group consisting of thermoplastic polymers, inorganic filler particles, and organic solvents. According to a preferred embodiment, the temporary fixative comprises at least one thermoplastic polymer, particularly preferably at least one compound selected from the group consisting of inorganic filler particles and organic solvents.

[0045] The thermoplastic polymer preferably has a glass transition temperature in the range of 60 to 120°C. The glass transition temperature is preferably determined by dynamic differential calorimetry (DDC) or differential scanning calorimetry (DSC) at a heating rate of 10°C / min. The thermoplastic polymer may be a (meth)acrylic copolymer in particular. The (meth)acrylic copolymer preferably has a molar mass in the range of 35,000 to 70,000 g / mol (Mw = 35,000 to 70,000 g / mol). The molar mass is preferably determined by gel permeation chromatography (GPC). For gel permeation chromatography, the following are used: polystyrene gel as the stationary phase and tetrahydrofuran or polystyrene standard as the mobile phase.

[0046] The inorganic filler particles are preferably particles containing at least one element selected from the group consisting of aluminum oxide, silicon dioxide, titanium dioxide, zirconium silicate, calcium silicate, mica, kaolin, and α-boron nitride. The inorganic filler particles preferably have an average particle size (d50) within the range of 5 to 20 μm, particularly preferably within the range of 5 to 10 μm. The average particle size (d50) is preferably determined by the laser diffraction method.

[0047] The organic solvent preferably has a boiling point of 285°C or lower. According to a preferred embodiment, the organic solvent is selected from the group consisting of aromatic, ketone, ester, glycol ether, and alcohol. According to a particularly preferred embodiment, the organic solvent is selected from the group consisting of toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, isobutyl acetate, dimethyl succinate, diethylene glycol monobutyl ether, benzyl alcohol, and terpineol. According to a very particularly preferred embodiment, the organic solvent is selected from the group of terpineol.

[0048] According to a further preferred embodiment, the lower surface of the substrate structure is formed by a contact layer or a temporary fixing layer.

[0049] The lower surface of the bonding substrate is (i) having an arithmetic mean roughness value R(1) along at least one section S1 a and (ii) having an arithmetic mean roughness value R(2) along at least one section S2, where at least one section S2 extends perpendicular to at least one section S1, a and provides a substrate structure in which the ratio Q of the arithmetic mean roughness value R(1) to the arithmetic mean roughness value R(2) a is within the range of 1.70 to 10.00. a The average roughness value is a measurement variable of the surface roughness. It is determined over a section. R

[0050] a ​This represents the arithmetic mean roughness value according to the standard DIN EN ISO 4287. Here, the mean roughness value R(1) a This represents the arithmetic mean of the absolute height values ​​along at least one section S1 and the mean roughness value R(2) a R(1) represents the arithmetic mean of the absolute height values ​​along at least one section S2, where at least one section S2 extends perpendicularly to at least one section S1. Thus, the mean roughness value R(1) a and average roughness value R(2) a The measurement is preferably carried out in accordance with the version of DIN EN ISO 4287 that is in effect on the filing date.

[0051] The lower surface of the bonding substrate has an arithmetic mean roughness value R(1) along at least one section S1. a It holds.

[0052] Arithmetic mean roughness value R(1) a The arithmetic mean roughness value R(1) is determined along at least one section S1. a The arithmetic mean roughness value R(1) is preferably determined along multiple sections S1. a Particularly preferably, the roughness is determined along multiple sections S1 that extend parallel to each other. Very particularly preferably, the arithmetic mean roughness value R(1) a The roughness is determined along at least 10 sections S1 extending parallel to each other. At least one section S1 preferably has a length of at least 20%, particularly preferably at least 25%, of the outer circumference of the bonding substrate. Preferably, the bonding substrate has two opposing edges Rd1a and Rd1b extending parallel to each other, which are spaced apart by section S(Rd)1, and the length of at least one section S1 is at least 50%, more preferably at least 75%, particularly preferably at least 90%, very particularly at least 95%, and especially the entire length of section S(Rd)1. aIf the length is determined along multiple sections S1, the value is relating to the length of at least one section S1, preferably the average length.

[0053] The lower surface of the bonding substrate has an arithmetic mean roughness value R(2) along at least one section S2. a It has such that at least one section S2 extends perpendicular to at least one section S1.

[0054] Arithmetic mean roughness value R(2) a The arithmetic mean roughness value R(2) is determined along at least one section S2. a The arithmetic mean roughness value R(2) is preferably determined along multiple sections S2. a Particularly preferably, the roughness is determined along multiple sections S2 that extend parallel to each other. Very particularly preferably, the arithmetic mean roughness value R(2) a The roughness is determined along at least 10 sections S2 that extend parallel to each other. At least one section S2 extends perpendicular to at least one section S1. At least one section S2 preferably has a length of at least 50% of the length of at least one section S1, particularly preferably at least 60%, and very particularly preferably at least 70%. Arithmetic mean roughness value R(1) a and R(2) aWhen the arithmetic mean roughness value R(2) is determined along multiple sections S1 and S2, section S2 has an average length of at least 50%, particularly preferably at least 60%, and very particularly preferably at least 70% of the average length of section S1. Preferably, the bonding substrate has two opposing edges Rd2a and Rd2b extending parallel to each other, these edges being separated by section S(Rd)2, and section S(Rd)2 extending perpendicular to section S(Rd)1. The length of at least one section S2 is preferably at least 50% of the length of section S(Rd)2, more preferably at least 75% of the length of section S(Rd)2, particularly preferably at least 90% of the length of section S(Rd)2, very particularly at least 95% of the length of section S(Rd)2, and particularly the entire length of section S(Rd)2. a If the length is determined along multiple sections S2, the value is given with respect to the length of at least one section S2, preferably with respect to the average length.

[0055] Arithmetic mean roughness value R(1) a R(2) a The ratio Q is in the range of 1.70 to 10.00.

[0056] Preferably, the arithmetic mean roughness value R(1) a R(2) a The ratio Q is in the range of 1.70 to 8.00, and is particularly preferably in the range of 2.00 to 8.00.

[0057] Surprisingly, the underside of the bonding substrate (i) has an arithmetic mean roughness value R(1) along at least one section S1 a (ii) having an arithmetic mean roughness value R(2) along at least one section S2 a It has a section S2 that extends perpendicularly to at least one section S1, and has an arithmetic mean roughness value R(1) a R(2) aA substrate structure having a bonding substrate designed such that the ratio Q is in the range of 1.70 to 10.00 has been found to enable a particularly stable and integrally bonded connection between the bonding substrate and the upper surface of the electronic component via a contact layer.

[0058] According to a preferred embodiment, the lower surface of the bonding substrate has a profile having structural repeating units along a first direction, and at least one section S1 extends in the first direction.

[0059] A profile having structural repeating units is preferably obtained by forming depressions on the lower surface of the bonding substrate. Thus, the structural repeating units may be, for example, a series of depressions. The depressions are preferably formed in an oriented manner. The lower surface of the bonding substrate along at least one section S1 preferably has an arithmetic mean roughness value R(2) along at least one section S2 extending perpendicular to at least one section S1. a A different arithmetic mean roughness value R(1) a It holds.

[0060] Preferably, the depression is introduced by rolling the lower surface of the bonding substrate. Here, a roller is guided along the rolling direction across the upper surface of the bonding substrate. Thus, the lower surface of the bonding substrate preferably has a rolled profile along the rolling direction, with at least one section S2 extending in the rolling direction.

[0061] According to a preferred embodiment, the substrate structure is suitable for connecting to at least one electronic component. In a particularly preferred embodiment, the substrate structure is suitable for connecting a bonding substrate to at least one electronic component.

[0062] The term "electronic component" is preferably understood to mean an electronic component or an electrical component. The electronic component is preferably selected from the group consisting of semiconductor components. The semiconductor component is preferably selected from the group consisting of transistors, diodes, and integrated circuits.

[0063] According to a preferred embodiment, the electronic component comprises a metal top coating. The metal top coating can function to allow for easy connection of the bonding substrate to the top surface of the electronic component via a contact layer. Therefore, it may be preferable that the top surface of the electronic component is formed by the metal top coating. The metal top coating of the electronic component preferably contains silver. According to a preferred embodiment, the electronic component comprises a metal bottom coating. The metal bottom coating can function to allow for easier connection of the base substrate to the bottom surface of the electronic component. Therefore, it may be preferable that the bottom surface of the electronic component is formed by the metal bottom coating. The metal bottom coating of the electronic component preferably contains at least one precious metal. According to a preferred embodiment, the metal bottom coating of the electronic component contains at least one element selected from the group consisting of silver, aluminum, titanium, and nickel, very preferably silver.

[0064] Electrical contact between the upper surface of an electronic component and an unmounted area of ​​the base substrate can preferably be prepared using a substrate structure. For this purpose, the bonding substrate is connected to the upper surface of the electronic component via a contact layer. The bonding substrate provides a particularly stable surface suitable for integrally bonded connections with bonding wires, especially copper bonding wires.

[0065] The method for manufacturing the substrate structure according to the present invention is not limited to the present invention.

[0066] According to a preferred embodiment, a method for manufacturing a substrate structure according to the present invention is: (A) The process of preparing metal foil, (B) A process of processing a metal foil to obtain a bonding substrate having an upper surface and a lower surface, wherein the lower surface of the bonding substrate is (i) Arithmetic mean roughness value R(1) along at least one section S1 a It has, (ii) Arithmetic mean roughness value R(2) along at least one section S2 a It has, and at least one section S2 extends perpendicularly to at least one section S1, Arithmetic mean roughness value R(1) a R(2) a The process has a ratio Q within the range of 1.70 to 10.00. (C) A step of preparing contact means, (D) A step of applying contact means to the lower surface of a bonding substrate to form a contact layer, wherein the contact layer is connected planarly to the lower surface of the bonding substrate in at least a region.

[0067] In step (A) of this method, metal foil is prepared.

[0068] The metal foil is preferably one of the metal foils described elsewhere in this specification. The metal foil may have a coating. On the other hand, the metal foil may not have a coating.

[0069] In step (B) of this method, the metal foil is processed to obtain a bonding substrate having an upper surface and a lower surface, the lower surface of the bonding substrate having an arithmetic mean roughness value R(1) along at least one section S1 a (ii) having an arithmetic mean roughness value R(2) along at least one section S2 a It has, and at least one section S2 extends perpendicularly to at least one section S1, and the arithmetic mean roughness value R(1) a R(2) a The ratio Q is in the range of 1.70 to 10.00.

[0070] Depending on the embodiment of the bonding substrate, the procedure may differ between steps (A) and (B).

[0071] When the bonding substrate includes a metal foil having a body but no coating, according to the first embodiment, in step (A), the metal foil without a coating can be prepared, and in step (B), at least one surface of the uncoated metal foil has an arithmetic mean roughness value R(1) in the range of 1.70 to 10.00. a R(2) a The metal foil can be processed to have a ratio Q.

[0072] When the bonding substrate includes a metal foil having a body and a coating, according to the second embodiment, in step (A), the metal foil having the coating can be prepared, and in step (B), the coated metal foil is preferably given an arithmetic mean roughness value R(1) in the range of 1.70 to 10.00 on the coated surface of the metal foil. a R(2) a It can be processed so that it has a ratio Q.

[0073] If the bonding substrate includes a metal foil comprising a body and a coating, according to the third embodiment, in step (A), an uncoated metal foil can be prepared, and in step (B), (i) at least one surface of the uncoated metal foil has an arithmetic mean roughness value R(1) in the range of 1.70 to 10.00. a R(2) a (ii) the uncoated metal foil is treated to have a ratio Q of (ii) then an arithmetic mean roughness value R(1) in the range of 1.70 to 10.00 a R(2) a A coating having a ratio Q is applied to at least one surface of an uncoated metal foil. In this case, the arithmetic mean roughness value R(1) a and the arithmetic mean roughness value R(2) aTherefore, preferably, the bonding substrate is required as described herein. The coating preferably has an arithmetic mean roughness value R(1) a R(2) a The coating is applied such that the ratio Q remains unchanged, for example, by electroplating or chemical deposition. The coating is preferably one of the coatings described elsewhere in this specification.

[0074] The processing of metal foil is not limited to any particular method.

[0075] In the processing of metal foil, the arithmetic mean roughness value R(1) a R(2) a To set the ratio Q to a range of 1.70 to 10.00, a depression is preferably introduced on the underside of the metal foil. The pressing of the depression on the underside of the metal foil can, in principle, be carried out by any method known to those skilled in the art and deemed appropriate.

[0076] According to a preferred embodiment, the metal foil is processed by a method selected from the group consisting of rolling, brushing, embossing, granulation, notching, stamping, countersinking, grooving, and etching.

[0077] In a particularly preferred embodiment, the metal foil is processed by rolling.

[0078] Rolling is understood to mean a processing method in which a material, in this case a metal foil, is processed between two or more rotating tools. Preferably, as a result of rolling, a relief is transferred to the metal foil. Rolling can be carried out as both hot rolling and cold rolling. Preferably, rolling is carried out as cold rolling.

[0079] According to a preferred embodiment, rolling is performed by at least one roller.

[0080] A roller is preferably understood to mean a substantially cylindrical body. In principle, a roller can have any desired diameter. Rollers with a diameter in the range of 50 to 150 mm are preferably suitable for the intended use. Furthermore, rollers should be formed from a material that is harder under operating conditions than the material of the metal foil. Therefore, a suitable roller can be formed from, for example, forged steel, cemented carbide, or cast steel.

[0081] In a preferred embodiment, rolling is performed using a mechanism comprising at least one roller. Mechanisms with multiple rollers, for example, two or more rollers, are also possible. For example, a mechanism in which at least two rollers rotate in opposite directions and the metal foil passes between two counter-rotating rollers is preferred. The two counter-rotating rollers are arranged so as to be spaced apart. This space preferably corresponds to the thickness of the bonding substrate.

[0082] The shape of the roller is not further limited. The rolling is preferably carried out using at least one roller having a cylindrical surface. The cylindrical surface of the roller preferably has relief.

[0083] The relief is preferably formed by structural units, which preferably result in a pattern. As the roller passes over the metal foil, the pattern on the cylindrical surface of the roller is introduced into the metal foil as a result of the arrangement.

[0084] The pattern is preferably characterized by an alternating arrangement of ridges along or perpendicular to the roller axis. The spacing of the ridges is determined by the arithmetic mean roughness value R(1). a R(2) a It can be adapted according to the desired ratio Q.

[0085] The pattern is more preferably characterized by the height difference of the cylindrical surface of the roller. Similarly, the height difference is the arithmetic mean roughness value R(1) a R(2) aThis can be adapted according to the desired ratio Q. The height difference of the cylindrical surface of the roller may be, for example, in the range of 2 to 10 μm. The depth of the indentation introduced into the metal foil depends here on the penetration depth of the relief of at least one roller into the metal foil. The height difference of the relief can be greater than the indentation introduced into the metal foil. Reshaping of metal foil by rollers, in which at least one first roller has a relief that is transferred to the metal foil during reshaping, is also called embossing rolling.

[0086] In a further embodiment, the metal foil is treated by stamping. The stamp is a surface on which relief is provided. The relief has a difference in height. In principle, all materials known to those skilled in the art and deemed suitable to those skilled in the art, especially the same material as the roller, are suitable for the stamp. During stamping, the stamp is lowered onto the metal foil. This results in an arithmetic mean roughness value R(1) a R(2) a The relief is pressed into the metal foil until the desired ratio Q is achieved. Preferably, during stamping the metal foil, an additional tool or plate is provided on the side of the metal foil opposite the stamp, designed to prevent the reshaped metal foil from escaping, for example, as a result of stamp bending. Rather, the reshaped metal foil is held in place with respect to the stamping direction by the additional tool.

[0087] In step (B), a bonding substrate having an upper surface and a lower surface is obtained, the lower surface of the bonding substrate having an arithmetic mean roughness value R(1) along at least one section S1 a (ii) having an arithmetic mean roughness value R(2) along at least one section S2 a It has, and at least one section S2 extends perpendicularly to at least one section S1, and the arithmetic mean roughness value R(1) a R(2) a The ratio Q is in the range of 1.70 to 10.00.

[0088] The bonding substrate obtained in step (B) may comprise a metal foil. The bonding substrate may be a metal foil. According to a preferred embodiment, the bonding substrate preferably comprises a metal foil having a body on which a coating can be placed, and the lower surface of the bonding substrate is formed by (i) the body if no coating is placed on the body, and (ii) the coating if a coating is placed on the body.

[0089] In step (C1) of this method, a contact means is prepared.

[0090] The contact means are preferably those described elsewhere in this specification.

[0091] In step (D) of this method, the contact means is applied to the lower surface of the bonding substrate to form a contact layer, in which case the contact layer is connected planarly to the lower surface of the bonding substrate in at least a certain area.

[0092] Applying a contact material to the underside of a bonding substrate to form a contact layer can be done by methods conventional in the art. Preferably, the contact material is applied by spraying, dispensing, atomizing, brushing, dubbing, dipping, or printing, particularly by screen printing or stencil printing.

[0093] In a preferred embodiment, in a further step (E), a temporary fixative is applied to the contact layer and / or to areas of the underside of the bonding substrate where the contact layer is not provided, thereby forming a temporary fixative layer which is connected to the contact layer and / or to areas of the bonding substrate where the contact layer is not provided. The temporary fixative is preferably one of those described elsewhere in this specification. The temporary fixative can be applied to the contact layer by methods conventional in the art. Preferably, the temporary fixative is applied by spraying, dispensing, atomizing, brushing, dubbing, dipping, or printing, particularly by screen printing or stencil printing.

[0094] According to a preferred embodiment, pre-drying is performed in a further step (F) of the method. Pre-drying can function to at least partially remove volatile components, such as organic compounds contained in the contact material and, if present, in the temporary fixative. Pre-drying can be performed, for example, at a temperature in the range of 80 to 150°C for, for example, 2 to 30 minutes. Pre-drying typically results in volume shrinkage, which in turn reduces the thickness of the contact layer and, if present, the thickness of the temporary fixative layer.

[0095] This method provides a substrate structure in which the bonding substrate can be connected to the upper surface of the electronic component via a contact layer in a particularly stable and integral manner.

[0096] The present invention relates to a method for manufacturing an electronic assembly.

[0097] This method involves the following steps, namely: (A) A step of preparing a base substrate including an upper surface and comprising a metal layer, (B) A step of preparing an electronic component having an upper surface and a lower surface, (C) A process of preparing the substrate components, (D) A step of bringing the upper surface of the base substrate into contact with the lower surface of the electronic component to form an integrally joined connection, (E) The process includes bringing the upper surface of an electronic component into contact with the contact layer of a substrate component to form an integrally joined connection.

[0098] In step (A) of this method, a base substrate is prepared. The base substrate comprises a metal layer. Furthermore, the base substrate has an upper surface.

[0099] For example, the metal layer of the base substrate may contain copper. Preferably, the metal layer of the base substrate can be formed from a metal foil. According to a preferred embodiment, the metal layer of the base substrate contains copper foil.

[0100] According to a preferred embodiment, the base substrate consists of a metal layer.

[0101] In another preferred embodiment, the base substrate comprises a metal layer and a layer of insulating material. In a further preferred embodiment, the base substrate comprises a metal layer and a layer of insulating material, which are connected to each other so as to be integrally bonded. The base substrate preferably comprises a layer of insulating material connected to the metal layer so as to be integrally bonded on a first surface and a second surface opposite to the first surface.

[0102] The insulating material of the base substrate is preferably selected from the group consisting of glass and ceramics. The ceramic can be selected from the group consisting of, for example, oxide ceramics, nitride ceramics, and carbide ceramics.

[0103] In a preferred embodiment, the base substrate is selected from the group consisting of a metal-ceramic substrate, a printed circuit board (PCB), and a lead frame. In a particularly preferred embodiment, the base substrate is a metal-ceramic substrate conventional in the art. The metal-ceramic substrate is preferably selected from the group consisting of a DCB (direct copper bond) substrate and an AMB (active metal brazing) substrate.

[0104] The upper surface of the base substrate is preferably formed by a metal layer.

[0105] In step (B) of this method, an electronic component is prepared. The electronic component has an upper surface and a lower surface.

[0106] The electronic components are preferably electronic components as described elsewhere in this specification.

[0107] In step (C) of this method, the substrate components are prepared.

[0108] The substrate component is preferably one of the substrate components described elsewhere in this specification.

[0109] Therefore, the substrate structure is preferably, (a) A bonding substrate having an upper surface and a lower surface, (b) A contact layer comprising contact means, the contact layer being connected planar to the lower surface of the bonding substrate in at least a region, The underside of the bonding substrate is (i) Arithmetic mean roughness value R(1) along at least one section S1 a It has, (ii) Arithmetic mean roughness value R(2) along at least one section S2 a It has, and at least one section S2 extends perpendicularly to at least one section S1, Arithmetic mean roughness value R(1) a R(2) a The present invention provides a substrate structure in which the ratio Q is in the range of 1.70 to 10.00.

[0110] In step (D) of this method, the upper surface of the base substrate is brought into contact with the lower surface of the electronic component, thereby forming an integrally joined connection.

[0111] For this purpose, the base substrate and the electronic components are preferably arranged such that the lower surface of the electronic components is in contact with the upper surface of the base substrate, preferably via a contact material. The contact means may be, for example, contact means as described elsewhere in this specification with respect to substrate components. Thus, the contact material may be, for example, a sintered paste, solder paste, or a conductive adhesive. The structure comprising the base substrate and the electronic components is then subjected to a process that enables a connection that is integrally joined via the contact material. In this case, the lower surface of the electronic components is fixed to the upper surface of the base substrate.

[0112] In step (E) of this method, the upper surface of the electronic component is brought into contact with the contact layer of the substrate component, thereby forming an integrally bonded connection. In this case, the formation of the integrally bonded connection is preferably performed between the upper surface of the electronic component and the bonding substrate.

[0113] For this purpose, the substrate structure and the electronic component are preferably arranged such that the contact layer of the substrate structure is in contact with the upper surface of the electronic component. The structure comprising the substrate structure and the electronic component is then subjected to a process that enables a jointly bonded connection via the contact material of the contact layer. The bonding substrate of the substrate structure is here fixed to the upper surface of the electronic component.

[0114] Steps (D) and (E) may be carried out in one manufacturing process or in different manufacturing processes. In this case, steps (D) and (E) may be carried out sequentially or simultaneously.

[0115] If processes (D) and (E) are performed consecutively, process (D) can be performed before process (E). On the other hand, it is also possible to perform process (E) before process (D).

[0116] When steps (D) and (E) are performed sequentially, according to the first embodiment, in step (D), the electronic component may be part of a first structure comprising the electronic component and a bonding substrate. In this case, first, in step (E), the upper surface of the electronic component is brought into contact with the contact layer of the substrate structure to form an integrally bonded connection between the upper surface of the electronic component and the bonding substrate, thereby manufacturing the first structure comprising the electronic component and the bonding substrate. This first apparatus may then be brought into contact with a base substrate in step (D), and as a result, the lower surface of the electronic component is connected to the upper surface of the base substrate by an integrally bonded connection as part of the first structure.

[0117] When steps (D) and (E) are performed sequentially, according to the second embodiment, in step (E), the electronic component may be part of a second structure comprising a base substrate and the electronic component. In this case, in step (D), a second structure comprising a base substrate and the electronic component can be manufactured first. This second structure can then be brought into contact with the substrate structure in step (E), so that the lower surface of the bonding substrate is connected to the upper surface of the electronic component as part of the second structure.

[0118] An electronic assembly is obtained by integrally bonding and connecting a base substrate, electronic components, and a bonding substrate.

[0119] According to a preferred embodiment, in a further step (F), the upper surface region of the bonding substrate is electrically contacted with the upper surface region of the base substrate. The electrical contact is preferably made by wire bonding. It is preferable to use a bonding wire for wire bonding. The bonding wire preferably contains copper. According to a preferred embodiment, the bonding wire is made of a material selected from the group consisting of copper and copper alloys.

[0120] Description of the method Average roughness R(1) a and average roughness R(2) aTo determine the surface roughness, 3D images of the planes containing each reference section S1 and S2 were taken from the underside of the bonding substrate using a confocal microscope μsurf custom (NanoFocus AG, Germany). The microscope 3D images were analyzed using the software μSoft Analysis Premium (7.4.8872; NanoFocus AG, Germany). For this purpose, any deflection of the bonding substrate in the 3D images was first corrected (using a polynomial of degree 2). Next, reference sections S1 and S2 (e.g., width 0.0315 mm) were defined, and roughness profiles were obtained along reference sections S1 and S2 using a Gaussian filter (0.8 mm). In each case, at least 10 reference sections S1 and at least 10 reference sections S2 of the same length extending parallel to each other were selected, with reference sections S2 extending perpendicular to reference sections S1 in each case. In this case, reference section S1 had a length of at least 20% of the outer circumference of the bonding substrate. The length of reference section S2 was at least 50% of the length of reference section S1. From the roughness profiles obtained along reference sections S1 and S2, the average roughness value R(1) a and average roughness value R(2) a This was determined according to the version of the standard DIN EN ISO 4287 that was in effect on the filing date. [Brief explanation of the drawing]

[0121] Further features and advantages of the present invention can be found in the following description, in which preferred embodiments of the present invention are described with reference to schematic drawings.

[0122] In the drawing, [Figure 1] A side view of the substrate structure according to the present invention is shown. [Figure 2] A side view of the substrate structure according to the present invention is shown. [Figure 3] A side view of an electronic assembly obtained by the method according to the present invention is shown.

[0123] Figure 1 shows a substrate structure 10 according to the present invention, which comprises a bonding substrate 20 and a contact layer 30. The bonding substrate 20 has an upper surface 23 and a lower surface 24. The contact layer 30 is connected planarly to the lower surface 24 of the bonding substrate 20. The lower surface 24 of the bonding substrate 20 has an arithmetic mean roughness value R(1) along at least one section S1. a (ii) an arithmetic mean roughness value R(2) along at least one section S2 a It has a section S2 that extends perpendicularly to at least one section S1, and has an arithmetic mean roughness value R(1) a R(2) a The ratio Q is in the range of 1.70 to 10.00.

[0124] Figure 2 shows a substrate structure 10 according to the present invention, which comprises a bonding substrate 20 and a contact layer 30. The bonding substrate 20 includes a metal foil comprising a body 26 on which a coating 27 is disposed. The lower surface 24 of the bonding substrate 20 is formed by the coating 27, and the upper surface 23 of the bonding substrate 20 is formed by the metal foil body 26. The lower surface 24 of the bonding substrate 20 has an arithmetic mean roughness value R(1) along at least one section S1. a (ii) an arithmetic mean roughness value R(2) along at least one section S2 a It has a section S2 that extends perpendicularly to at least one section S1, and has an arithmetic mean roughness value R(1) a R(2) a The ratio Q is in the range of 1.70 to 10.00.

[0125] Figure 3 shows an electronic assembly 100 that can be manufactured by the method according to the present invention. The electronic assembly 100 comprises a bonding substrate 20, an electronic component 40, and a base substrate 50. The base substrate 50 has a layer of insulating material 56 that is planarly connected to metal layers 55, 55' on both sides. The base substrate 50 is typically a metallic ceramic substrate. The upper surface 53 of the base substrate 50 is formed by the metal layer 55. The electronic component 40, having an upper surface 43 and a lower surface 44, is positioned on the upper surface 53 of the base substrate 50. The lower surface 44 of the electronic component 40 is positioned on the upper surface 53 of the base substrate 50. The electronic component 40 is planarly connected to the base substrate 50. For this purpose, the electronic component 40 can be fixed to the base substrate 50 using, for example, a sintered paste. Thus, a sintered layer (not shown) can be located between the upper surface 53 of the base substrate 50 and the lower surface 44 of the electronic component 40. The electronic component 40 is connected to the bonding substrate 20. The bonding substrate 20 has an upper surface 23 and a lower surface 24. The lower surface 24 of the bonding substrate 20 is positioned on the upper surface 43 of the electronic component 40. The bonding substrate 20 is fixed to the electronic component 40. Fixing is first performed by positioning a substrate structure comprising the bonding substrate 20 and a contact layer on the upper surface 43 of the electronic component 40 such that the contact layer is in contact with the upper surface 43 of the electronic component 40. The structure thus obtained is then exposed to conditions that allow for the formation of an integrally bonded connection between the bonding substrate 20 and the electronic component 40. The contact layer may consist of, for example, a pre-dried sintered paste. In this case, the structure is exposed to temperature and pressure to allow for the formation of a sintered connection between the bonding substrate 20 and the electronic component 40. The electronic assembly 100, in this case, includes a sintered layer (not shown) between the bonding substrate 20 and the electronic component 40. The upper surface 23 of the bonding substrate 20 can be brought into contact with bonding wires having an unmounted area (not shown) on the upper surface 53 of the base substrate 50. The upper surface 23 of the bonding substrate 20 can also be connected to further components, particularly using a sintered material (not shown), so as to be integrally bonded to them. [Examples]

[0126] Manufacture of Substrate Structure - Example 1: Using a copper foil with a thickness of 50 μm, a substrate structure according to Example 1 was manufactured. The lower surface of the copper foil had an arithmetic mean roughness value R(1) according to Table 1 a , arithmetic mean roughness value R(2) a , and arithmetic mean roughness value R(1) a to the ratio Q of the arithmetic mean roughness value R(2) a . The copper foil was rolled so as to have the ratio Q. The arithmetic mean roughness value R(1) a and arithmetic mean roughness value R(2) a were determined as described above. The copper foil was structured into copper foil pieces with dimensions of 4 mm × 8 mm by photolithographic etching using appropriate masking with an iron chloride (FeCl3) etching solution, and the individual copper foil pieces were still connected to each other via a web. Then, the masking was removed. As a result, a bonding substrate connected to each other via a web was obtained, each of which had an upper surface and a lower surface, and the lower surface of the bonding substrate had an arithmetic mean roughness value R(1) according to Table 1 a , arithmetic mean roughness value R(2) a , and arithmetic mean roughness value R(1) a to the ratio Q of the arithmetic mean roughness value R(2) a .

[0127] Next, a contact layer was provided on the lower surface of the bonding substrate. For this purpose, a sintering paste (ASP338 - 28, Heraeus) was applied to a 3 mm × 3 mm area of the lower surface of the bonding substrate by screen printing (wetting layer thickness = 50 μm). Except for the area with the sintering paste, the lower surface of the bonding substrate had a free area of 4.0 mm × 4.5 mm in addition to a peripheral area with a width of 0.5 mm that did not contain the sintering paste. The bonding substrate provided with the contact layer in this way was then dried at 100 °C for 10 minutes in an air atmosphere and separated into individual pieces by laser separation of the web, obtaining a substrate structure according to Example 1

[0128] Manufacture of Substrate Structure - Examples 2 to 7 and Comparative Examples 1 to 4: The substrate assemblies of Examples 2 to 7 and Comparative Examples 1 to 4 were prepared in the same manner as the substrate assembly of Example 1, except that the arithmetic mean roughness value R(1) a , the arithmetic mean roughness value R(2) a , and the ratio Q of the arithmetic mean roughness value R(1) a to the arithmetic mean roughness value R(2) a were varied according to Table 1. For this purpose, commercially available copper foils were sometimes used. In some cases, the arithmetic mean roughness value R(1) a , the arithmetic mean roughness value R(2)<00001!>, and the ratio Q of the arithmetic mean roughness value R(1) a to the arithmetic mean roughness value R(2) a were set by changing the rolling process (using rollers with different patterns, arrangements of ridges on the rollers, and differences in the height of the cylindrical surface of the rollers), and different profiles were obtained on the lower surface of the copper foil.

[0129] Manufacture of an electronic assembly - Example 1: To manufacture an electronic assembly, a structure consisting of a base substrate and an electronic component was first formed. A commercially available direct metallization copper - ceramic substrate (DCB; Condura® classic, Heraeus) and, as the electronic component, a silicon chip having a metallized part (100 nm aluminum, 50 nm titanium, 100 nm nickel, and finally 700 nm silver) on the lower surface and a metallized part (700 nm, silver) on the upper surface, with dimensions of 4 mm × 4 mm (thickness = 250 μm) was used as the base substrate.

[0130] A sintering paste (ASP 338 - 28, Heraeus) was applied to the upper surface of the copper - ceramic substrate by screen printing (wet layer thickness = 100 μm). The copper - ceramic substrate with the sintering paste was dried in an air atmosphere at 100°C for 10 minutes and then cooled. The silicon chip was placed on the pre - dried sintering paste such that the lower surface of the silicon chip contacted the upper surface of the copper - ceramic substrate.

[0131] Next, the substrate assembly according to Example 1 was placed on the upper surface of the silicon chip so that the contact layer of the substrate assembly was in contact with the upper surface of the silicon chip. The free region on the lower surface of the bonding substrate protruded beyond the upper surface of the silicon chip.

[0132] Next, the obtained structure was sintered. Sintering was carried out in a PINK sintering press (Pink, Wertheim) in a nitrogen atmosphere at a pressure of 20 MPa and a temperature of 250°C for 3 minutes. An electronic assembly was obtained.

[0133] Manufacturing of Electronic Assemblies - Examples 2-7 and Comparative Examples 1-4: The electronic assemblies were also manufactured using the substrate components of Examples 2-7 and Comparative Examples 1-4. This was done in the same manner as the manufacturing of the electronic assembly having the substrate component of Example 1.

[0134] Adhesion strength test: The bonding strength of the bonding substrate on the top surface of the silicon chip was investigated for electronic assemblies manufactured using the substrate components of Examples 1-7 and Comparative Examples 1-4. Using a ZwickRoell (500N, ZwickRoell GmbH & Co KG) material testing machine, the force required to remove the bonding substrate, which is integrally bonded and connected to the top surface of the silicon chip, was measured. For this purpose, the electronic assemblies manufactured using the substrate components of Examples 1-7 and Comparative Examples 1-4 were fixed to a clamping device, and the free region protruding beyond the top surface of the silicon chip was fixed to the underside of the bonding substrate using a screw tension device. The bond was then removed at a speed of 50 mm / min at a 90-degree peeling angle. The bonding strength was then applied on a scale from ++ (very high bonding strength) to -- (very low bonding strength). The results are shown in Table 1.

[0135] [Table 1]

[0136] As the results show, using the substrate structures of Examples 1 to 7 according to the present invention, a particularly stable and integrally bonded connection between the bonding substrate and the upper surface of the electronic component was achieved via the contact layer. The integrally bonded connection is more stable than the integrally bonded connection obtained with the substrate structures of Comparative Examples 1 to 4. [Explanation of symbols]

[0137] 10 Substrate components 20 Bonding substrates 23 Top view (bonding substrate) 24. Bottom view (bonding substrate) 26 Main unit 27 Coating 30 Contact layer 40 Electronic Components 43 Top side (electronic components) 44 Bottom side (electronic components) 50 base boards 53 Top view (base board) 55, 55' metal layer 56 Layers of insulating material 100 Electronic Assembly

Claims

1. (a) A bonding substrate having an upper surface and a lower surface, (b) A contact layer comprising contact means, the contact layer being connected planar to the lower surface of the bonding substrate in at least a region, In a substrate structure comprising, The lower surface of the bonding substrate is (i) an arithmetic mean roughness value R(1) along at least one section S1 ａ It has, (ii) Arithmetic mean roughness value R(2) along at least one section S2 ａ It has such that the at least one section S2 extends perpendicularly to the at least one section S1, Arithmetic mean roughness value R(1) ａ R(2) ａ The ratio Q is characterized in that it is in the range of 1.70 to 10.

00. Circuit board components.

2. The substrate structure according to claim 1, characterized in that the lower surface of the bonding substrate has a profile having structural repeating units along a first direction, and at least one section S1 extends in the first direction.

3. The substrate structure according to claim 1 or 2, characterized in that the lower surface of the bonding substrate has a rolled profile along the rolling direction, and at least one section S2 extends in the rolling direction.

4. The substrate structure according to any one of claims 1 to 3, characterized in that the bonding substrate comprises a metal foil.

5. The substrate structure according to claim 4, characterized in that the metal foil contains copper.

6. The substrate structure according to claim 4 or 5, characterized in that the metal foil comprises a body and a coating.

7. The substrate structure according to claim 6, characterized in that the lower surface of the bonding substrate is formed by the coating.

8. The substrate structure according to claim 6 or 7, characterized in that the coating contains a precious metal.

9. The substrate structure according to any one of claims 1 to 8, characterized in that the contact means includes a sintered material.

10. The substrate structure according to claim 9, characterized in that the sintered material contains at least one element selected from the group consisting of silver and copper.

11. The substrate structure according to claim 9 or 10, characterized in that the sintered material includes a sintered paste.

12. The substrate structure according to claim 11, characterized in that the sintered paste is pre-dried.

13. Arithmetic mean roughness value R(1) ａ R(2) ａ A substrate structure according to any one of claims 1 to 12, characterized in that the ratio Q is in the range of 1.70 to 8.

00.

14. The substrate structure according to any one of claims 1 to 13, characterized in that the substrate structure is designed to be connected to at least one electronic component.

15. A method for manufacturing an electronic assembly, (A) A step of preparing a base substrate having an upper surface and comprising a metal layer, (B) A step of preparing an electronic component having an upper surface and a lower surface, (C) A step of preparing a substrate structure according to any one of claims 1 to 14, (D) A step of bringing the upper surface of the base substrate into contact with the lower surface of the electronic component to form an integrally joined connection, (E) A step of bringing the upper surface of the electronic component into contact with the contact layer of the substrate component to form an integrally joined connection, Methods that include...

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