DE102012110382B4 - Substrate and method for manufacturing a substrate - Google Patents

Abstract

Substrate, in particular in the form of a printed circuit board for electrical circuits and / or modules, with at least one insulating layer (2), with at least one metallization (3, 4), preferably with at least one metallization formed at least partially by a metal layer or metal foil, and with at least a solder stop structure (5) delimiting a bond area (6) formed on the metallization (3, 4) and / or on a surface or final layer (9), the solder stop structure (5) being made of a metallic oxide, preferably a metallic oxide of the Metallization (3, 4) and / or a metallic oxide of the surface or final layer (9) applied to the metallization and the oxide or oxide layer is produced without material removal, characterized in that the solder stop structure (5) over the level protruding from the adjacent exposed outer surface of the metallization (3, 4) or the surface or final layer (9) eht.

Description

The invention relates to a substrate, in particular in the form of a printed circuit board, according to the preamble of patent claim 1 and to a method for producing a substrate, in particular in the form of a printed circuit board, in accordance with the preamble of claim 10.

Substrates in the form of printed circuit boards consisting of an insulating layer made of a polymeric material and / or ceramic, of at least one metallization connected to one surface side of the insulating layer and structured to form conductor tracks, contacts, contact or fastening areas are known in various designs. Also known here are those areas of the metallization (hereinafter referred to as soldering or bonding areas) that are provided for connecting connecting lines, circuit or module components, etc., in particular also for connecting electrical components and / or their connections by soldering are to be provided on the side with a solder stop structure that forms a barrier for the liquid solder. These solder stop structures usually consist of an application or a layer made of a polymeric and / or inorganic material and have to be applied in a relatively complex process. The particular disadvantage here is that several additional process steps are required for the application of the known solder stop structures, that the known solder stop structures have only a low temperature resistance when using a polymeric material, and when using an inorganic material an additional baking step is required which increases the manufacturing costs of the substrate, which usually also requires a special oven. Furthermore, the known lacquers or pastes used for solder stop structures basically contain solvents which, in particular, also evaporate during stoving and represent a burden on the environment. Furthermore, maintaining a desired layout for the respective solder stop structure is often difficult and the desired quality of adhesion of the solder stop structure to the substrate is often not achieved.

Processes for the production of substrates in the form of printed circuit boards for electrical circuits and / or modules are also known ( DE 10 2008 042 777 A1 ), the printed circuit boards each consisting of an insulating layer and a single-layer metallization on at least one surface side of the insulating layer. A surface or final layer is applied to the respective metallization connected to the insulating layer. To form a solder stop structure surrounding a bonding or soldering area, an oxide is produced from the metal of the metallization by lasing. At the same time, material of the surface or termination layer is removed or vaporized with the laser, so that the solder stop structure consists of a trench created in the surface or termination layer, the bottom of which is formed by the oxide of the metallization.

Also known is the so-called “DCB process” (Direct Copper Bond Technology), for example, for connecting metal layers or sheets (e.g. copper sheets or foils) to one another and / or to ceramic or ceramic layers, namely under Use of metal or copper sheets or metal or copper foils which have a layer or a coating (melted layer) made of a chemical compound of the metal and a reactive gas, preferably oxygen, on their surface sides. For example, in the U.S. 3,744,120 A or in the DE 23 19 854 A described method, this layer or this coating (melting layer) forms a eutectic with a melting temperature below the melting temperature of the metal (e.g. copper), so that by placing the foil on the ceramic and heating all the layers, these can be connected to one another, and although by melting the metal or copper essentially only in the area of the melting layer or oxide layer.

• • Oxidieren einer Kupferfolie derart, dass sich eine gleichmäßige Kupferoxidschicht ergibt;
• • Auflegen des Kupferfolie auf die Keramikschicht;
• • Erhitzen des Verbundes auf eine Prozesstemperatur zwischen etwa 1025 bis 1083°C, z. B. auf ca. 1071°C;
• • Abkühlen auf Raumtemperatur.

This DCB method then has z. B. the following process steps:

• • Oxidizing a copper foil in such a way that a uniform copper oxide layer results;
• • Placing the copper foil on the ceramic layer;
• • Heating the composite to a process temperature between about 1025 to 1083 ° C, z. B. to about 1071 ° C;
• • Cooling down to room temperature.

The so-called active soldering process is also known ( DE 22 13 115 A ; EP 0 153 618 A2 ) z. B. for connecting metal layers or metal foils which form metallizations, in particular also copper layers or copper foils with ceramic material. In this method, which is also used specifically for the production of metal-ceramic substrates, a connection between a metal foil, for example copper foil, and a ceramic substrate, for example aluminum nitride ceramic, is made using a at a temperature between approx. 800-1000 ° C Hard solder produced, which in addition to a main component such as copper, silver and / or gold also contains an active metal. This active metal, which is, for example, at least one element from the group Hf, Ti, Zr, Nb, Ce, creates a compound through chemical reaction between the solder and the ceramic, while the connection between the solder and the metal is a metallic braze connection.

From FIG. 4 there is a method for producing a solder stop barrier with the introduction of energy on the surface of a carrier in order to reduce the wettability of this surface with liquid solder in the irradiated area. This reaction concerns an oxidation of the carrier material located on the surface in the area of the track or solder stop track generated with a laser beam.

The DE 103 51 120 A1 also relates to a solder stop barrier and a method for its production. The solder stop barrier is formed here by removing material by means of laser radiation, namely by making a laser trench in a coating of a carrier.

The DE 10 2008 042 777 A1 relates to a method for producing a surface on a component which has areas with a different wettability with respect to a solder.

The DE 10 2005 042 554 A1 relates to a hybrid ceramic with a core layer made of silicon nitride and an oxide ceramic as a cover layer.

The US 7 037 597 B2 describes a laser treatment of a copper foil and the DE 100 27732 A1 relates to the creation of scratch lines using laser light.

The invention is based on the object of providing a substrate which avoids the aforementioned disadvantages and in which the respective solder stop structure is produced in a time-saving and cost-effective manner. To achieve this object, a substrate is designed in accordance with claim 1. A method for producing the substrate is the subject of claim 10.

The particular advantage of the invention consists inter alia. in that the respective solder stop structure or the respective solder stop pattern can be produced without complex process steps, without additional work equipment and without environmental pollution, namely with an optimal adhesion of the solder stop structure to the respective substrate or the metallization. Furthermore, by controlling the relative movement between the substrate and the laser beam, the solder stop structure can be produced in the desired layout without problems and, for example, under program and / or computer control, in particular also in a fine and differentiated form. Solvents and the associated pollution are avoided with the invention.

The metal oxide forming the solder stop structure is preferably produced in such a way that the metal oxide extends at least up to the level of an adjacent exposed metal surface, preferably protrudes above this level. The effect of heat (e.g. lasers) takes place in any case in such a way that there is no material removal or essentially no material removal (e.g. by evaporation), neither on the substrate or on the insulating layer, nor on the respective metallization. This also applies if the metallization is additionally provided with at least one outer metallic finishing layer, i.e. H. the metallization consists for example of copper or aluminum and is provided with a nickel layer or with a nickel layer and an outer gold layer as the final layer. In order to achieve this and to avoid material removal or metal removal (e.g. by evaporation), it is necessary that the heat treatment (e.g. laser) takes place in an atmosphere with an oxygen content not below 10%. In the case of a final layer made of nickel, the metal oxide forming the solder stop structure is inter alia. Nickel oxide. This also applies in the case of a final layer composed of an inner nickel layer or an outer gold layer adjacent to the metallization, the nickel here diffusing through the gold layer. The action of heat (for example lasers) for generating the solder stop structure is preferably set in such a way that, in the case of a final layer, only or essentially its oxide forms the solder stop structure.

In a particular embodiment, the respective substrate is part of a multiple substrate produced as a multiple use, in which several individual substrates or their metallizations are produced on a large-format insulating layer by structuring metal layers or metal foils applied to the insulating layer, as is, for example, in FIG DE 43 19 944 A1 is described. If the multiple substrate is separated into the individual substrates or if separating and / or break lines are created in the insulating layer to separate the multiple substrate into the individual substrates by lasers or by laser treatment, then there is optimally the possibility of this separation or at the same time Producing the separating or breaking lines, also producing the solder stop structures or solder stop patterns by lasers or laser treatment, or at least using one and the same laser for this purpose.

In a further development of the invention, the substrate is also designed, for example,
that the at least one metallization at least partially from a copper layer, preferably from a copper layer with a thickness in the range between 0.015 mm to 0.8 mm and the oxide layer from a copper oxide, preferably with a thickness in Area between 0.00015 mm to 0.1 mm are formed, and / or
that the at least one metallization is at least partially formed by a layer of aluminum, preferably with a thickness in the range between 0.015 mm to 0.8 mm and the oxide layer of aluminum oxide, preferably with a thickness in the range between 0.005 mm to 0.1 mm,
and or
that the at least one metallization is designed in at least two layers with a copper or aluminum layer adjoining the insulating layer and with an at least one-layer, preferably thin surface or final layer on the surface side of the copper or aluminum layer facing away from the insulating layer,
and or
that the surface or final layer is a nickel layer, preferably with a thickness in the range between 0.002 mm and 0.015 mm,
and or
that the surface or final layer is a layer of silver, preferably with a layer thickness in the range between 0.00015 mm and 0.05 mm, and / or
that the surface or final layer is a layer made of gold, for example with a layer thickness in the range between 0.0001 mm and 0.015 mm,
and or
that the surface or final layer is a layer of silver or gold with a layer thickness in the range between 0.01 µm and 3 µm,
and or
that the surface or final layer is multilayered and consists of at least the nickel layer adjoining the copper or aluminum layer and the silver and / or gold layer adjoining the side of the nickel layer facing away from the insulating layer,
and or
that the oxide layer forming the solder stop structure consists essentially of nickel oxide,
and or
that the oxide layer forming the solder stop structure extends at least to the level of the outer surface of the metallization or the surface or final layer, preferably protrudes beyond this level,
and or
that the oxide layer forming the solder stop structure has a layer thickness in the range between 0.0001 mm and 0.015 mm,
and or
that the solder stop structure encloses the at least one soldering or bonding area,
and or
that the solder stop structure has a width in the range between 0.1 mm and 1.2 mm,
and or
that the insulating layer is made of plastic, for example fiber-reinforced plastic,
and or
that the insulating layer is made of plastic, for example fiber-reinforced plastic and has a thickness in the range between 0.015 mm and 3.0 mm, and / or
that the insulating layer is a ceramic layer, preferably made of aluminum oxide, aluminum nitride, silicon nitride or aluminum oxide with zirconium oxide,
and or
that the insulating layer is a ceramic layer, preferably made of aluminum oxide, aluminum nitride, silicon nitride or mixed ceramics made of aluminum oxide with zirconium oxide, for example aluminum oxide with 1% by weight to 23% by weight of zirconium oxide and a thickness in the range between 0.15 mm and 1, 5 mm,
and or
that the at least one metallization is connected to the insulating layer by gluing or active soldering or DCB bonding,
and or
that a solder layer is applied to the at least one bonding or soldering area,
and or
that a solder layer is applied to the at least one bonding or soldering area and a component ( 8th ) is connected to the substrate,
it being possible for the aforementioned features to be used individually or in any combination.

In a further development of the invention, the method is designed, for example, so
that the partial conversion of the metal of the at least one metallization into the oxide forming the solder stop structure takes place through the introduction of heat and / or through chemical oxidation,
and or
that the partial conversion of the metal of the at least one metallization into that of the solder stop structure ( 5 ) forming oxide by laser treatment, for example with a YAG or CO2 or Eximer laser,
and or
that the partial conversion of the metal of the at least one metallization into that of the solder stop structure ( 5 ) forming oxide takes place through an oxidizing microflame,
and or
that the partial conversion of the metal into the oxide forming the solder stop structure takes place in an oxygen-containing atmosphere with an oxygen content of at least 10%, for example in an oxygen-containing atmosphere with an oxygen content between 21% and 99%,
and or
that the laser treatment is carried out through a mask,
and or
that the laser treatment is carried out by a relative movement between a laser beam and the substrate in the direction of the course of the solder stop structure and also by a circular and / or oscillating relative movement, in particular by an oscillating relative movement transverse to the course of the solder stop structure, and / or
that the partial conversion of the metal into the oxide forming the solder stop structure takes place in such a way that the oxide layer forming the solder stop structure extends at least to the level of the outer surface of the metallization or the surface or final layer, preferably protrudes above this level,
and or
that the partial conversion of the metal of the at least one metallization into the oxide forming the solder stop structure takes place after the application of an at least one-layer metallic surface or final layer to a metal layer connected to the insulating layer, for example made of copper or aluminum,
and or
that the partial conversion of the metal of the at least one metallization into the oxide forming the solder stop structure takes place in such a way that the oxide layer forming the solder stop structure is formed only or essentially by at least one metal of the surface or final layer,
and or
that the surface or final layer or at least a partial layer of this surface or final layer consists of nickel, gold, silver or nickel, gold, silver alloys,
and or
that with an at least two-layer formation of the surface or final layer ( 9 ) a first partial layer made of nickel and a further partial layer connected to the first partial layer made of silver and / or gold, adjoining the metal layer or metallization connected to the insulating layer, and / or
that with an insulating layer made of ceramic, for example made of aluminum oxide, aluminum nitride, silicon nitride or aluminum oxide with zirconium oxide, the at least one metallization consisting of copper or aluminum by DCB bonding or active soldering or by gluing, preferably by gluing with a carbon fiber or carbon nanofiber containing adhesive is connected to the insulating layer,
and or
that in the case of an insulating layer made of a polymeric material, the at least one metallization with the insulating layer by gluing, preferably with a polymeric adhesive, e.g. B. is connected with an adhesive containing polymeric carbon fibers and / or carbon nofibers,
and or
that the partial conversion of the metal into the metal oxide forming the solder stop structure takes place using a mask,
and or
that the partial conversion of the metal into the metal oxide forming the solder stop structure is carried out using a mask by chemical or wet-chemical oxidation over the mask,
and or
that a solder layer is applied to the at least one bonding or soldering area after the solder stop structure has been produced,
and or
that at least one electrical component ( 8th ) over the solder layer ( 7th ) is connected to the substrate or the at least one metallization,
and or
that when manufacturing the substrates in a multiple use or in a multiple substrate and when separating the multiple substrate into the substrates or when introducing separating or predetermined breaking lines in the insulating layer between the substrates by laser treatment in this process step or at least with the same laser, also the solder stop structures or solder stop patterns be generated,
it being possible for the aforementioned features to be used individually or in any combination.

In the context of the invention, the expression “without material removal” means that no material or essentially no material is removed, for example by evaporation, when the metal oxide forming the solder stop structure is generated.

The expression “essentially” or “approximately” means deviations from the exact value of +/- 10%, preferably +/- 5% and / or deviations in the form of changes that are insignificant for the function.

Developments, advantages and possible applications of the invention also emerge from the following description of exemplary embodiments and from the figures. In this case, all of the features described and / or shown in the figures, individually or in any combination, are fundamentally the subject matter of the invention, regardless of how they are summarized in the claims or their reference. The content of the claims is also made part of the description.

The invention is explained in more detail below with reference to the figures using exemplary embodiments.

• 1-3 verschiedene Verfahrensschritte zur Herstellung eines weiteren Substrates gemäß der Erfindung, wobei das Substrat sowie die verschiedenen, dieses Substrat bildenden Schichten in vereinfachter Schnittdarstellung wiedergegeben sind;
• 4 in vereinfachter Darstellung eine Draufsicht auf das nach den 1-3 hergestellte Substrat;
• 5 eine vergrößerte Schnittdarstellung des Substrates der 3 und 4 im Bereich des Lötstoppmusters;
• 6 und 7 eine Darstellung wie 5, jedoch mit Lotschicht und aufgelötetem Bauelement;
• 8-11 verschiedene Verfahrensschritte zur Herstellung eines weiteren Substrates gemäß der Erfindung, wobei das Substrat sowie die verschiedenen, dieses Substrat bildenden Schichten wiederum in vereinfachter Schnittdarstellung wiedergegeben sind;
• 12 eine Draufsicht auf das entsprechend den 8-11 hergestellte Substrat;
• 13 eine vergrößerte Schnittdarstellung des Substrates der 11 und 12 im Bereich des Lötstoppmusters, zusammen mit der Lotschicht;
• 14-18 verschiedene Verfahrensschritte zur Herstellung eines weiteren Substrates gemäß der Erfindung, wobei das Substrat sowie die verschiedenen, dieses Substrat bildenden Schichten wiederum in vereinfachter Schnittdarstellung wiedergegeben sind;
• 19 eine Draufsicht auf das nach den 14-18 hergestellte Substrat;
• 20 in vergrößerter Schnittdarstellung das Substrat der 18 und 19 im Bereich des Lötstoppmusters;
• 21 in schematischer Darstellung ein Verfahren zum Erzeugen des Lötstoppmusters unter Verwendung einer Maske.

Show it:

• 1-3 various process steps for the production of a further substrate according to the invention, the substrate and the various layers forming this substrate being shown in a simplified sectional illustration;
• 4th in a simplified representation a plan view of the after 1-3 manufactured substrate;
• 5 an enlarged sectional view of the substrate of FIG 3 and 4th in the area of the solder stop pattern;
• 6th and 7th a representation like 5 , but with solder layer and soldered component;
• 8-11 various method steps for producing a further substrate according to the invention, the substrate and the various layers forming this substrate again being shown in a simplified sectional illustration;
• 12 a plan view of the corresponding to 8-11 manufactured substrate;
• 13 an enlarged sectional view of the substrate of FIG 11 and 12 in the area of the solder stop pattern, together with the solder layer;
• 14-18 various method steps for producing a further substrate according to the invention, the substrate and the various layers forming this substrate again being shown in a simplified sectional illustration;
• 19th a top view of the after 14-18 manufactured substrate;
• 20th in an enlarged sectional view the substrate of 18th and 19th in the area of the solder stop pattern;
• 21st a schematic representation of a method for generating the solder mask using a mask.

That in the 1-7 The substrate, generally designated 1, consists essentially of an insulating layer 2 that have a metallization on their two surface sides 3 or. 4th in the form of a metal layer or metal foil, preferably made of copper or of a copper alloy or of aluminum or of an aluminum alloy. The metallization 3 is for the formation of metal areas 3.1 and 3.2 structured in the form of conductor tracks, contact surfaces, assembly and / or fastening surfaces, etc. On at least one of the metal areas, for example on the metal area 3.2 is at least one solder stop structure or one solder stop pattern 5 generated, which in the illustrated embodiment, a soldering or bonding area 6th encloses.

According to the 1 and 2 the substrate is first produced by placing the insulating layer on the two surface sides 2 the metallizations 3 and 4th be applied ( 1 ) and then, preferably in a masking and etching process, the metallization 3 to form the electrically separated metal areas 3.1 and 3.2 is structured ( 2 ). The application of the solder mask 5 takes place as a metal oxide layer by partial oxidation of the metal of the metal area 3.2 , namely by energy or heat or heat input, for example by laser treatment with a laser and / or by treatment with a microflame, etc. The heat or heat input that occurs in the 3 is indicated schematically with the local arrow A, takes place in an oxygen-containing atmosphere with an oxygen content of at least 10%, for example in an atmosphere with an oxygen content in the range between 21% and 99%, so that the solder resist structure or the solder resist pattern 5 forming metal oxide layer is produced without material removal, ie in particular without evaporation of metal, rather the entire metal partially subjected to the energy, heat or heat input is converted into metal oxide and the solder stop structure or the solder stop pattern 5 forming metal oxide layer protrudes above the level of the adjacent outer surface of the respective metallization. The solder stop pattern is also applied 5 in the illustrated embodiment so that the solder stop pattern 5 from metal oxide, preferably from copper oxide (CuO, Cu2O, CuO + Cu2O) or aluminum oxide the bond area 6th encloses.

The heat input leads to the formation of the solder mask 5 by means of a laser beam with relative movement between the laser beam and the substrate 1 generated, the laser beam is not only generated along the course of the solder stop pattern 5 moved, but preferably also circling and / or oscillating, in particular transversely to this course, so that for the linear solder stop pattern 5 a sufficient width and / or thickness is achieved.

A laser treatment with a YAG laser or CO ₂ laser or excimer laser, for example with a YAG laser with a power between 30 W and 100 W, with a CO ₂ laser with a power, is particularly suitable for applying the solder stop pattern between 50 W and 300 W or with an eximer laser with a power between 30 W and 150 W. The laser treatment is carried out by direct irradiation of the metal area 3.2 or using a mask.

The metallizations 3 and 4th have a sufficient thickness, preferably a thickness in the range between 0.015 mm and 0.8 mm. The thickness of the solder mask pattern 5 The metal oxide layer forming the metal oxide layer is preferably in the range between 0.00015 mm and 0.1 mm for a copper oxide layer and preferably in the range between 0.005 mm and 0.1 mm for an aluminum oxide layer. In the embodiment shown, the line width of the solder stop pattern is in the range between 0.1 mm and 1.2 mm.

The insulating layer 2 consists for example of a preferably fiber-reinforced polymer, such as epoxy, polyamide, Teflon, and has z. B. a layer thickness in the range between 0.015 mm and 3.0 mm.

For the insulating layer 2 ceramics are also suitable, in particular made of aluminum oxide (Al ₂ O ₃ ) and / or aluminum nitride (AlN) and / or of silicon nitride (Si ₃ N ₄ ) and / or of aluminum oxide with zirconium oxide (Al ₂ O3 + ZrO ₂ ). The thickness of the insulating layer 2 forming ceramic is for example in the range between 0.15 mm and 1.5 mm.

I.a. taking into account that for the insulating layer 2 and / or the metallizations 3 and 4th The materials used are suitable for the areal joining or bonding of the metallizations 3 and 4th forming metal layers or metal foils in different processes. This is how the metallizations are 3 and 4th forming metal layers or metal foils, for example by gluing using a plastic adhesive or a polymer suitable as an adhesive, preferably using an adhesive that contains carbon fibers, in particular carbon nanofibers, with the insulating layer 2 connected. The glue residue that is not required between the metal areas 3.1 and 3.2 are removed by suitable methods, preferably before the application of the solder mask 5 he follows.

Is the insulating layer 2 made of ceramic and in particular made of one of the aforementioned ceramics (Al ₂ O ₃ , AlN, Si3N4, Al2O3 + ZrO2), the metallizations are connected 3 and 4th forming metal layers or foils using the DCB process, in particular in the case of metallizations 3 and 4th made of copper or copper alloy, or with the help of the active soldering process, especially with metallizations 3 and 4th made of copper or aluminum.

To complete the substrate 1 and to prepare for the use of this substrate 1 As a printed circuit board for electrical circuits or modules, preference is given to that of the solder stop pattern 5 enclosed bond area 6th the plumb bob 7th upset ( 6th ), with which then when populating the substrate 1 the relevant electrical component 8th , in particular also electrically with the substrate 1 or with the metal areas there 3.1 and 3.2 can be connected ( 7th ).

11 and 12 show a substrate in a simplified representation 1a which differs from the substrate 1 essentially only differs in that after the metallizations have been applied 3 and 4th on the insulating layer 2 ( 8th ) and after structuring the metallization 3 ( 9 ) on the metal areas formed in this way 3.1 and 3.2 a single-layer metallic protective or surface or finishing layer 9 is applied ( 10 ), namely in the illustrated embodiment a metallic surface or finishing layer 9 made of nickel. The application of the surface or finishing layer 9 takes place in a suitable process, for example galvanically and / or by chemical deposition and / or by spraying or cold gas spraying. Particularly when using nickel, the metallic surface or final layer has 9 for example a layer thickness in the range between 0.02 mm and 0.015 mm. After applying the metallic surface or finishing layer 9 in turn, controlled, partial heat input creates the solder stop pattern 5 each in the form of a respective bond area 6th surrounding line-like oxide layer. If the surface or finishing layer exists 9 The respective solder stop pattern consists of a metal which forms an oxide when exposed to heat, for example nickel 5 from the oxide of this metal or from a mixed oxide containing at least the oxide of this metal, for example nickel oxide, for example with a layer thickness in the range between 0.0001 mm and 0.015 mm.

For the surface or top layer 9 other metals are also suitable, for example silver or gold. With a surface or finishing layer 9 made of silver, this is applied with a layer thickness in the range between 0.00015 mm and 0.05 mm, preferably with a layer thickness in the range between 0.01 μm and 3 μm. When using gold for the surface or finishing layer 9 this is applied with a layer thickness in the range between 0.0001 mm and 0.015 mm, preferably with a layer thickness in the range between 0.01 μm and 3 μm. When coating the surface 9 the solder-stop pattern is made from silver and / or gold 5 from an oxide layer of the oxide of an underlying metal e.g. B. the metallization 3 , ie formed for example by copper oxide or aluminum oxide. Regardless of the one used for the surface or top layer 9 The materials used will be the respective solder mask pattern 5 in turn preferably produced with a line width in the range between 0.1 mm and 1.2 mm.

Through the surface coating 9 which in particular also includes the surface of the bond area 6th forms, the application of the solder layer or the solder there 7th and the connection of the plumb bob 7th improved with the bond area.

The 14th to 20th show a substrate as a further embodiment 1b which differs from the substrate 1a essentially only differs in that the surface or top layer 9 Is executed in multiple layers, namely consisting of a directly on the metallization 3 or on the metal areas 3.1 and 3.2 applied partial layer 9.1 of a metal that forms an oxide under the action of heat, preferably nickel, and one of the partial layers 9.1 covering outer layer made of precious metal, preferably made of silver or gold. The layer thickness of the partial layer 9.1 is for example again in the range between 0.002 mm and 0.015 mm and the layer thickness of the partial layer 9.2 made of silver in the range between 0.00015 mm and 0.05 mm or the partial layer 9.2 made of gold in the range between 0.0001 mm and 0.015 mm. When creating the solder stop pattern 5 the metal (nickel) of the partial layer diffuses through the application of heat 9.1 the sub-layer 9.2 so that the solder mask pattern 5 again from the oxide of the metal of the partial layer 9.1 or essentially from the oxide of the metal of the partial layer 9.1 , is formed for example by nickel oxide (NiO), with a thickness of the partial layer 9.1 in the range between 0.002 mm and 0.015 mm with a layer thickness in the range between 0.0001 mm and 0.015 mm. As the 14-18 show the production of the substrate takes place 1b again in such a way that after the application of the metallizations 3 and 4th on the insulating layer 2 ( 14th ) and after structuring the metallization 3 ( 15th ) in two steps the ( 16 and 17th ) the partial layers are applied, for example galvanically and / or by chemical deposition and / or by spraying or cold gas spraying.

The connection, and in particular the electrical connection, of the substrate, which in turn is used as a printed circuit board 1a and 1b with the components 8th takes place in the same way as above in connection with the substrate 1 has been described. The substrates are also preferred 1a and 1b after the at least one solder stop pattern has been generated 5 at the respective bond area 6th with the plumb bob 7th Mistake.

Is the surface coating 9 with a partial layer 9.1 made of nickel and with a partial layer 9.2 made of silver or gold, the laser treatment can in particular also take place in such a way that not only the material of the partial layer 9.2 , but also the nickel of the partial layer 9.1 largely evaporated and the solder stop pattern 5 as an oxide or oxide layer of the metal of the metallization 3 trains, e.g. B. as copper oxide or aluminum oxide.

As mentioned above, the solder stop pattern is generated 5 for example by laser radiation or laser treatment. The 21st shows a schematic representation of the laser treatment using a mask 11 . In this way, even with a laser beam A with a relatively large beam diameter, by appropriately designing the mask 11 very fine structures for the respective solder stop pattern 5 can be achieved.

The invention was described above using exemplary embodiments. It goes without saying that numerous changes and modifications are possible without departing from the inventive concept on which the invention is based.

It was assumed above that the solder mask 5 are generated from the metal oxide through the input of heat or heat. In principle, there is also the possibility of using the solder stop pattern 5 to produce from the metal oxide by chemical and in particular wet chemical oxidation using at least one mask and an oxidizing medium, this medium then being applied by dipping and / or spraying through the mask used onto the metallic surface of the substrate. Furthermore, there is basically also the possibility of applying the oxidizing medium as a gel-like medium partially and along the stop pattern to be generated to the metallic surface of the substrate, for example also by printing.

It was assumed above that the metallizations 3 and 4th are formed by metal foils. Other methods such as B. the application of the metallizations 3 and 4th through thick film technology, spray technology (cold gas spraying) etc. are possible. Furthermore, the metallizations 3 and or 4th can also be applied to the insulating layer in a pre-structured manner. It has also been shown that the respective solder stop pattern 5 can be produced particularly optimally with a JAG laser with a pump power of 50 kW at a pulse frequency of 10 KHz. For example, a JAG laser that is offered by the Trumpf company under the name VMc3 is suitable for this purpose. Furthermore, it has been shown that the through a circular or circular relative movement between the laser beam and the substrate 1 , 1a , 1b generated circular melts or oxidation structures in the solder stop pattern 5 and / or in the solder stop pattern 5 the solder flow when soldering components 8th , Connections, etc. particularly well obstructed, ie form a particularly effective barrier for the solder flow.

By traversing the solder stop pattern several times, for example twice 5 a significant improvement in the solder-stop or barrier effect can be achieved.

Will the substrate 1 , 1a , 1b manufactured as a multiple use or as a multiple substrate and the multiple substrate is separated into the substrates in a laser treatment step 1 , 1a , 1b or the introduction of separating or predetermined breaking lines in the insulating layer 2 for separating the multiple substrate by breaking it into the substrates 1 , 1a , 1b , the solder stop patterns are preferred in this process step, but at least with the same laser at the same time 5 generated.

Claims (19)

Substrate, in particular in the form of a printed circuit board for electrical circuits and / or modules, with at least one insulating layer (2), with at least one metallization (3, 4), preferably with at least one metallization formed at least partially by a metal layer or metal foil, and with at least a solder stop structure (5) delimiting a bonding area (6) formed on the metallization (3, 4) and / or on a surface or final layer (9), the solder stop structure (5) being made of a metallic oxide, preferably a metallic oxide of the Metallization (3, 4) and / or a metallic oxide of the surface or final layer (9) applied to the metallization and the oxide or oxide layer is produced without material removal, characterized in that the solder stop structure (5) over the level the adjacent exposed outer surface of the metallization (3, 4) or the surface or final layer (9) does. Substrate after Claim 1 , characterized in that the at least one metallization consists of a copper layer, preferably a copper layer with a thickness in the range between 0.015 mm to 0.8 mm, or a layer made of aluminum, preferably with a thickness in the range between 0.015 mm to 0, 8 mm, and that the oxide layer is formed from an oxide of the metal of the metallization, preferably from a copper oxide with a thickness in the range between 0.00015 mm to 0.1 mm or from an aluminum oxide, preferably with a thickness in the range between 0.005 mm is formed up to 0.1 mm. Substrate after Claim 1 or 2 , characterized in that on the metallization (3, 4) adjoining the insulating layer (2), preferably in the form of a copper or aluminum layer, an at least one-layer surface or cover layer (9) is applied, that the surface or cover layer ( 9) preferably a nickel layer or a layer of a nickel alloy with a thickness in the range between 0.002 mm and 0.015 mm, and / or a layer of silver, preferably with a layer thickness in the range between 0.00015 mm and 0.05 mm, for example with a layer thickness in the range between 0.01 μm and 3 μm, and / or a layer of gold, for example with a layer thickness in the range between 0.0001 mm and 0.015 mm, for example with a layer thickness in the range between 0.01 μm and 3 µm. Substrate after Claim 3 , characterized in that the surface or final layer (9) is multi-layered and consists at least of the nickel layer adjoining the copper or aluminum layer and of the silver and / or gold layer or of nickel, gold, silver alloys, the side of the nickel layer facing away from the insulating layer (2). Substrate after Claim 3 or 4th , characterized in that the oxide layer forming the solder stop structure (5) consists essentially of a metal oxide of the surface or final layer (9), preferably nickel oxide, and that the oxide layer forming the solder stop structure (5) preferably has a layer thickness in the range between 0, 0001 mm and 0.015 mm. Substrate according to one of the preceding claims, characterized in that the solder stop structure (5) encloses the at least one soldering or bonding area (6). Substrate according to one of the preceding claims, characterized in that the solder stop structure (5) has a width in the range between 0.1 mm and 1.2 mm. Substrate according to one of the preceding claims, characterized in that the insulating layer (2) consists of plastic, for example of fiber-reinforced plastic and preferably has a thickness in the range between 0.015 mm and 3.0 mm, and / or that the insulating layer (2) has a Ceramic layer, preferably made of aluminum oxide, aluminum nitride, silicon nitride or aluminum oxide with zirconium oxide and preferably has a thickness in the range between 0.15 mm and 1.5 mm, and that the at least one metallization (3, 4), for example by gluing or active soldering or DCB -Bonding is connected to the insulating layer (2). Substrate according to one of the preceding claims, characterized in that a solder layer (7) is applied to the at least one bonding or soldering area (6), wherein, for example, a component (8) with the substrate (1, 1a , 1b) is connected. Method for producing a substrate (1, 1a, 1b), in particular in the form of a printed circuit board for electrical circuits and / or modules, with an insulating layer and with at least one at least one-layer metallization (3, 4) on one surface side of the insulating layer (2) and with at least one at least one solder stop structure (5) which at least partially delimits a bond or soldering area (6) on the metallization (3, 4) or on a surface or final layer (9), the solder stop structure (5) being partially converted by Metal of the at least one metallization (3, 4) and / or the surface or final layer (9) applied to the metallization (3, 4) is produced in an oxide or in an oxide layer, namely after structuring the at least one metallization ( 3, 4) and wherein the oxide or the oxide layer is produced without material removal, characterized in that one up to the level of the adjacent exposed outer surface of the Metallization (3, 4) or the surface or final layer (9) reaching and above this level protruding solder stop structure (5) is produced. Procedure according to Claim 10 , characterized in that the partial conversion of the metal of the at least one metallization (3, 4) and / or the surface or final layer (9) into the oxide forming the solder stop structure (5) takes place through the introduction of heat and / or through chemical oxidation, for example by laser treatment, e.g. B. with a YAG or CO2 or Eximer laser, and / or by an oxidizing microflame. Method according to one of the Claims 10 or 11 , characterized in that the partial conversion of the metal into the oxide forming the solder stop structure takes place in an oxygen-containing atmosphere with an oxygen content of at least 10%, for example in an atmosphere with an oxygen content between 21% and 99%. Method according to one of the Claims 10 to 12 , characterized in that a laser treatment via a mask and / or by relative movement between a laser beam and the substrate (1, 1a, 1b) in the direction of the course of the solder stop structure (5) as well as by a circular and / or oscillating relative movement, for example by an oscillating relative movement takes place transversely to this course. Method according to one of the Claims 10 to 13 , characterized in that the oxide layer (5) forming the solder stop structure (5) after the application of an at least one-layer metallic surface or final layer (9) to the metallization (3, 4) connected to the insulating layer (2), for example made of copper or Aluminum takes place, with the surface or final layer (9) or at least one partial layer (9.1, 9.2) of this surface or final layer (9) made of nickel, gold, silver or, in the case of an at least two-layer formation of the surface or final layer (9) the first sublayer (9.1) adjoining the metallization (3, 4) is made of nickel and another sublayer (9.2) adjoining the first sublayer (9.1) consists of silver and / or gold. Procedure according to Claim 14 , characterized in that the oxide layer (5) forming the solder stop structure (5) is produced exclusively or essentially exclusively from the metal of the surface or final layer (9). Method according to one of the Claims 10 to 15th , characterized in that with an insulating layer (2) made of ceramic, for example made of aluminum oxide, aluminum nitride, silicon nitride or aluminum oxide with zirconium oxide, the at least one metallization made of copper or aluminum by DCB bonding or active soldering or by gluing, preferably by gluing with a Carbon fibers or carbon nanofibers containing adhesive is connected to the insulating layer (2), and / or that in the case of an insulating layer (2) made of a polymer material, the at least one metallization (3, 4) is bonded to the insulating layer, preferably with a polymeric adhesive, e.g. B. is connected to an adhesive containing polymeric carbon fibers and / or carbon nofibers. Method according to one of the Claims 10 to 16 , characterized in that a solder layer (7) and / or at least one electrical component (8) over the solder layer (7) to the substrate or is applied to the at least one bonding or soldering area (6) after the solder stop structure (5) has been produced the at least one metallization (3, 4) or its surface or final layer (9) is connected. Method according to one of the Claims 10 to 17th , characterized in that at least one metallization (3, 4) is applied to the insulating layer (2) as a pre-structured metal layer or metal foil or by thick film technology and / or spraying. Method according to one of the Claims 10 to 18th , characterized in that when the substrates are produced in a multiple use or in a multiple substrate and when the multiple substrate is separated into the substrates (1, 1a, 1b) or when separating or predetermined breaking lines are introduced in the insulating layer (2) between the substrates ( 1, 1a, 1b) by laser treatment in this process step or at least with the same laser also the Solder stop structures or solder stop patterns (5) are generated.

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