DE102012110382A1 - Substrate i.e. printed circuit board, for electrical circuits and/or modules, has stop structure extending up to level of adjacent exposed outer surface of metallization regions or surface of end layer projects above level - Google Patents

Abstract

The substrate (1) has an insulating layer (2) with metallization regions (3, 4) formed by a metal film or a metal foil, and/or on a surface of an end layer formed by bonding areas defining a metallic oxide stop structure. The stop structure is formed at a surface or the end layer. The stop structure extends up to a level of an adjacent exposed outer surface of the metallization regions or the surface of the end layer projects above the level. The metallization regions are formed by a copper layer, an aluminum layer or an oxide layer. An independent claim is also included for a method for manufacturing a substrate.

Description

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

Substrates in the form of printed circuit boards consisting of an insulating layer of a polymeric material and / or of ceramic, at least one connected to a surface side of the insulating layer and to form interconnects, contacts, contact or mounting areas structured metallization are known in various designs. It is also known, such areas of metallization (hereinafter referred to as soldering or bonding areas), which provided for a connection of leads, circuit or module components, etc., in particular for a connection of electrical components and / or their connections by soldering are to be provided laterally with a, a barrier for the liquid solder forming solder stop structure. Usually, these solder stop structures consist of an order or of a layer of a polymeric and / or inorganic material and must be applied in a relatively expensive process. The disadvantage here is in particular that for the application of the known Lötstoppstrukturen several additional process steps are required that the known Lötstoppstrukturen using a polymeric material have only low temperature resistance and when using an inorganic material, an additional, the production cost of the substrate more expensive burn-in is required which usually also requires a special oven. Furthermore, the known paints or pastes used for solder resist structures generally contain solvents which, in particular, also evaporate during stoving and represent a burden on the environment. Furthermore, compliance with a desired layout for the respective solder stop structure is often difficult and the desired quality of the adhesion of the solder stop structure on the substrate is often not achieved.

Methods are also known for producing substrates in the form of printed circuit boards for electrical circuits and / or modules ( DE 10 2008 042 777 A1 ), wherein the printed circuit boards each consist of an insulating layer and of a single-layer metallization on at least one surface side of the insulating layer. On the respective associated with the insulating metallization a surface or finishing layer is applied. In order to form a solder stop structure surrounding a bonding or soldering area, an oxide is produced from the metal of the metallization by means of lasers. At the same time, material of the surface or final layer is removed or evaporated with the laser, so that the solder stop structure consists of a trench produced in the surface or final layer, the bottom of which the oxide of the metallization is formed.

Also known is the so-called "DCB method" (direct copper bond technology), for example, for connecting metal layers or sheets (eg copper sheets or sheets) to one another and / or to ceramic or ceramic layers, namely under Use of metal or copper sheets or metal or copper foils having on their surface sides a layer or coating (reflow layer) of a chemical compound of the metal and a reactive gas, preferably oxygen. In this example, in the US-PS 37 44 120 or in the DE-PS 23 19 854 described method, this layer or this coating (melting layer) forms a eutectic having a melting temperature below the melting temperature of the metal (eg., Copper), so that by laying the film on the ceramic and by heating all the layers, they can be joined together, and Although by melting the metal or copper substantially only in the region of the melting 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 steps:

• • Oxidizing a copper foil so 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;
• • Cool to room temperature.

Also known is the so-called active soldering method ( DE 22 13 115 ; EP-A-153 618 ) z. B. for joining metallizations forming metal layers or metal foils, in particular also of copper layers or copper foils with ceramic material. In this method, which is also used especially for the production of metal-ceramic substrates, at a temperature between about 800-1000 ° C, a connection between a metal foil, such as copper foil, and a ceramic substrate, such as aluminum nitride ceramic, using a brazing filler metal, which also contains an active metal in addition to a main component such as copper, silver and / or gold. This active metal, which is, for example, at least one element of the group Hf, Ti, Zr, Nb, Ce, establishes a chemical bond between the solder and the ceramic, while the bond between the solder and the metal is a metallic braze joint ,

The invention has for its object to provide a substrate which avoids the aforementioned disadvantages and in which the respective Lötstoppstruktur is made time-saving and inexpensive. To solve this problem, a substrate according to claim 1 is formed. A method for producing the substrate is the subject of patent claim 10.

The particular advantage of the invention is u. a. The fact that the respective Lötstoppstruktur or the respective Lötstoppmuster can be prepared without complex process steps, without additional equipment and without environmental pollution, with an optimal adhesion of the Lötstoppstruktur 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 without problems and, for example, program-controlled and / or computer-controlled in the desired layout, in particular also in a fine and differentiated form. Solvent and the associated environmental impact are avoided with the invention.

The production of the metal oxide forming the solder stop structure preferably takes place in such a way that the metal oxide extends at least as far as the level of an adjacent exposed metal surface, preferably protruding above this level. In any case, the effect of heat (eg lasers) is such that there is no removal of material or essentially no material removal (eg by evaporation), neither at the substrate or at the insulating layer, nor at the respective metallization. This is true even if the metallization is additionally provided with at least one outer metallic end layer, d. H. the metallization consists for example of copper or aluminum and is provided as a final layer with a nickel layer or with a nickel layer and an outer gold layer. In order to achieve this and to avoid material removal or metal removal (eg by evaporation), it is necessary that the heat treatment (eg lasers) takes place in an atmosphere whose oxygen content is not less than 10%. In the case of a final layer of nickel, the metal oxide forming the solder stop structure u. a. Nickel oxide. This also applies in the case of a top layer of internal nickel layer or metal layer adjacent to the metallization and outer gold layer, wherein the nickel diffuses through the gold layer. The heat action (eg lasers) for the production of the solder stop structure is preferably adjusted such that only or essentially its oxide forms the solder stop structure in the case of a terminating layer.

In a particular embodiment, the respective substrate is part of a multiple substrate produced as Mehrfachnutzen, in which a plurality of individual substrates or their metallizations are produced by structuring applied to the insulating metal layers or metal foils on a large-sized insulating layer, as for example in the DE 43 19 944 A1 is described. If the separation of the multi-substrate into the individual substrates or the production of separation and / or break lines in the insulating layer for separating the multiple substrate into the individual substrates by laser or by laser treatment, there is an optimal way at the same time in this separation or Generating the separation or break lines and the solder stop patterns or solder stop pattern to produce by laser or laser treatment or to use at least one and the same laser.

In a development of the invention, for example, the substrate is also designed
the at least one metallization is at least partially composed of a copper layer, preferably of a copper layer having a thickness in the range of 0.015 mm to 0.8 mm and the oxide layer of a copper oxide, preferably of a thickness in the range of 0.00015 mm to 0.1 mm are formed,
and or
the at least one metallization is formed at least partially by a layer of aluminum, preferably with a thickness in the range between 0.015 mm and 0.8 mm, and the oxide layer of aluminum oxide, preferably with a thickness in the range between 0.005 mm and 0.1 mm,
and or
that the at least one metallization is embodied in at least two layers with a copper or aluminum layer adjoining the insulating layer and with an at least single-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
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 of gold, for example with a layer thickness in the range between 0.0001 mm and 0.015 mm,
and or
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
the surface or cover layer 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 which adjoins 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 of the surface or outer layer, preferably protruding above this level,
and or
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 surrounds the at least one soldering or bonding region,
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 of fiber-reinforced plastic,
and or
that the insulating layer consists of plastic, for example of fiber-reinforced plastic and has a thickness in the range between 0.015 mm and 3.0 mm,
and or
in that the insulating layer is a ceramic layer, preferably of aluminum oxide, aluminum nitride, silicon nitride or aluminum oxide with zirconium oxide,
and or
in that the insulating layer is a ceramic layer, preferably of aluminum oxide, aluminum nitride, silicon nitride or mixed ceramic of aluminum oxide with zirconium oxide, for example of aluminum oxide with 1% by weight to 23% by weight zirconium oxide and a thickness in the range between 0.15 mm and 1, 5 mm,
and or
the at least one metallization is connected to the insulating layer by gluing or active soldering or DCB bonding,
and or
in that a solder layer is applied to the at least one bonding or soldering region,
and or
in that a solder layer is applied to the at least one bonding or soldering area and a component is applied via the soldering layer ( 8th ) is connected to the substrate,
wherein the aforementioned features can be used individually or in any combination.

In a development of the invention, the method is, for example, designed in such a way, for example.
the partial transformation of the metal of the at least one metallization into the oxide forming the solder stop structure takes place by heat input and / or by chemical oxidation,
and or
in that the partial conversion of the metal of the at least one metallization into the solder stop structure ( 5 ) forming oxide by laser treatment, for example with a YAG or CO2 or Eximer laser occurs,
and or
in that the partial conversion of the metal of the at least one metallization into the solder stop structure ( 5 ) forming oxide by an oxidizing micro-flame,
and or
in that the partial conversion of the metal into the oxide forming the solder stop structure takes place in an oxygen-containing atmosphere having an oxygen content of at least 10%, for example in an oxygen-containing atmosphere having an oxygen content between 21% and 99%,
and or
that the laser treatment takes place via a mask,
and or
the laser treatment takes place by relative movement between a laser beam and the substrate in the direction of the course of the solder stop structure as well as 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
in 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 as far as the level of the outer surface of the metallization or the surface or outer layer, preferably above this level,
and or
in 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 single-layer metallic surface or final layer to a metal layer, for example made of copper or aluminum, connected to the insulating layer,
and or
in that the partial transformation 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 substantially only by at least one metal of the surface or final layer,
and or
that the surface or finishing layer or at least a sub-layer of this surface or Final layer consists of nickel, gold, silver or nickel, gold, silver alloys,
and or
in the case of at least two-ply formation of the surface or outer layer ( 9 ) a first partial layer of nickel adjoining the metal layer or metallization connected to the insulating layer and a further partial layer of silver and / or gold adjoining the first partial layer,
and or
in the case of an insulating layer of ceramic, for example of aluminum oxide, aluminum nitride, silicon nitride or aluminum oxide with zirconium oxide, the at least one copper or aluminum metallization by DCB bonding or active soldering or by gluing, preferably by gluing with a carbon fiber or carbon nanofibers containing adhesive is connected to the insulating layer,
and or
that in an insulating layer of a polymeric material, the at least one metallization with the insulating layer by gluing, preferably with a polymeric adhesive, for. B. is bonded to a polymeric carbon fiber and / or carbon nofasern containing adhesive,
and or
the partial conversion of the metal into the metal oxide forming the solder stop structure takes place using a mask,
and or
in that the partial conversion of the metal into the metal oxide forming the solder stop structure takes place by means of a mask by chemical or wet chemical oxidation over the mask,
and or
in that a soldering layer is applied to the at least one bonding or soldering area after the soldering-stop structure has been produced,
and or
that at least one electrical component ( 8th ) over the solder layer ( 7 ) is connected to the substrate or the at least one metallization,
and or
that in a production of the substrates in a multiple use or in a multi-substrate and in separating the multi-substrate into the substrates or when introducing separation 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 and the Lötstoppstrukturen or Lötstoppmuster be generated,
wherein the aforementioned features can be used individually or in any combination.

The term "without material removal" in the sense of the invention means that no material or substantially no material is removed, for example by evaporation, when the metal oxide forming the solder stop structure is produced.

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

Further developments, advantages and applications of the invention will become apparent from the following description of exemplary embodiments and from the figures. In this case, all described and / or illustrated features alone or in any combination are fundamentally the subject of the invention, regardless of their summary in the claims or their dependency. Also, the content of the claims is made an integral part of the description.

The invention will be explained in more detail below with reference to the figures of exemplary embodiments. Show it:

1 - 3 Various process steps for the production of a further substrate according to the invention, wherein the substrate and the various layers forming this substrate are shown in a simplified sectional view;

4 in a simplified representation of a plan view of the after 1 - 3 prepared substrate;

5 an enlarged sectional view of the substrate of 3 and 4 in the area of the solder stop pattern;

6 and 7 a representation like 5 but with solder layer and soldered component;

8th - 11 Various process steps for producing a further substrate according to the invention, wherein the substrate and the various layers forming this substrate are again shown in a simplified sectional view;

12 a plan view of the corresponding to the 8th - 11 prepared substrate;

13 an enlarged sectional view of the substrate of 11 and 12 in the area of the solder stop pattern, together with the solder layer;

14 - 18 Various process steps for producing a further substrate according to the invention, wherein the substrate and the various layers forming this substrate again shown in simplified sectional view;

19 a plan view of the after 14 - 18 prepared substrate;

20 in an enlarged sectional view of the substrate of 18 and 19 in the area of the solder stop pattern;

21 a schematic representation of a method for generating the solder stop pattern using a mask.

That in the 1 - 7 generally with 1 designated substrate consists essentially of an insulating layer 2 , which on its two surface sides, each with a metallization 3 respectively. 4 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 education of metal areas 3.1 and 3.2 in the form of printed conductors, contact surfaces, mounting and / or mounting surfaces, etc. structured. On at least one of the metal areas, for example on the metal area 3.2 is at least one solder stop structure or a solder stop pattern 5 generated, which in the illustrated embodiment, a soldering or bonding area 6 encloses.

According to the 1 and 2 The production of the substrate is initially characterized in that on the two surface sides of the insulating layer 2 the metallizations 3 and 4 be applied ( 1 and subsequently, preferably in a masking and etching process, the metallization 3 for forming the electrically separated metal areas 3.1 and 3.2 is structured ( 2 ). The application of the solder stop pattern 5 takes place as a metal-oxide layer by partial oxidation of the metal of the metal region 3.2 By energy or heat or heat input, for example by laser treatment with a laser and / or by treatment with a micro-flame, etc. The heat or heat input, in the 3 is schematically indicated by the local arrow A, takes place in an oxygen-containing atmosphere having 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 Lötstoppstruktur or the Lötstoppmuster 5 forming metal oxide layer without material removal, ie in particular without vaporization of metal is produced, but the entire partially acted upon by the energy or heat or heat input metal is converted into metal oxide and the Lötstoppstruktur or the Lötstoppmuster 5 forming metal oxide layer protrudes beyond the level of the adjacent outer surface of the respective metallization. Furthermore, the application of the solder stop pattern takes place 5 in the illustrated embodiment, such that the solder stop pattern 5 made of metal oxide, preferably of copper oxide (CuO, Cu2O, CuO + Cu2O) or aluminum oxide, the bonding region 6 encloses.

If the heat input to the formation of the solder stop pattern 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 along the course of the solder stop pattern 5 moves, but preferably also circular and / or oscillating, in particular transversely to this course, so that the line-shaped Lötstoppmuster 5 a sufficient width and / or thickness is achieved.

For the application of the solder stop pattern, in particular, a laser treatment with a YAG laser or CO2 laser or Eximer laser, for example with a YAG laser with a power between 30 W and 100 W, with a CO2 laser with a power between 50 is 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 4 have a sufficient thickness, preferably a thickness in the range between 0.015 mm and 0.8 mm. The thickness of the solder stop pattern 5 forming metal oxide layer is preferably in the range between 0.00015 mm and 0.1 mm in a copper-oxide layer and in an aluminum oxide layer preferably in the range between 0.005 mm and 0.1 mm. The line width of the solder stop pattern is in the illustrated embodiment in the range between 0.1 mm and 1.2 mm.

The insulating layer 2 consists for example of a preferably fiber-reinforced polymer, for example of 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 Also suitable are ceramics, in particular 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 O 3 + 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.

U. a. taking into account that for the insulating layer 2 and / or the metallizations 3 and 4 , used materials are suitable for the surface bonding or bonding of the metallizations 3 and 4 forming metal layers or metal foils in different processes. This is how the metallizations become 3 and 4 forming metal layers or metal foils, for example by gluing under Use of a plastic adhesive or a polymer suitable as an adhesive, preferably using an adhesive containing carbon fibers, in particular carbon nanofibers, with the insulating layer 2 connected. The unneeded adhesive residue between the metal areas 3.1 and 3.2 are removed by appropriate methods, preferably before the application of the solder stop pattern 5 he follows.

Is the insulating layer 2 made of ceramic and in particular of one of the aforementioned ceramics (Al 2 O 3, AlN, Si 3 N 4, Al 2 O 3 + ZrO 2), then the joining of the metallizations takes place 3 and 4 forming metal layers or films using the DCB process, especially in metallizations 3 and 4 made of copper or copper alloy, or by means of the active soldering process, in particular in metallizations 3 and 4 made of copper or aluminum.

To complete the substrate 1 and to prepare for the use of this substrate 1 as a circuit board for electrical circuits or modules is preferred to that of the Lötstoppmuster 5 enclosed bond area 6 the lot 7 applied ( 6 ), with which when loading the substrate 1 the relevant electrical component 8th , in particular also electrically with the substrate 1 or with the local metal areas 3.1 and 3.2 can be connected ( 7 ).

11 and 12 show a simplified representation of a substrate 1a which is different from the substrate 1 essentially only differs in that after the application of the metallizations 3 and 4 on the insulating layer 2 ( 8th ) and after structuring the metallization 3 ( 9 ) on the metal areas formed in this case 3.1 and 3.2 a single-layer metallic protective or surface or finishing layer 9 is applied ( 10 ), 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 method, for example galvanically and / or by chemical deposition and / or by spraying or cold gas spraying. In particular, when using nickel has the metallic surface or finishing layer 9 For example, a layer thickness in the range between 0.02 mm and 0.015 mm. After applying the metallic surface or finishing coat 9 In turn, the formation of the Lötstoppmuster done by controlled, partial heat input 5 each in the form of a bond area in question 6 enclosing line-like oxide layer. Consists of the surface or finishing layer 9 from a forming in the action of heat an oxide metal, such as nickel, so there is the respective Lötstoppmuster 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 finishing layer 9 Other metals are also suitable, for example silver or gold. For 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 .mu.m and 3 .mu.m. When using gold for the surface or finish coat 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 .mu.m and 3 .mu.m. In the surface coating 9 silver and / or gold becomes the solder stop pattern 5 from an oxide layer of the oxide of an underlying metal z. As the metallization 3 , ie formed for example of copper oxide or aluminum oxide. Regardless of those for the surface or finishing layer 9 used materials is the respective solder stop pattern 5 again preferably produced with a line width in the range between 0.1 mm and 1.2 mm.

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

The 14 - 20 show as a further embodiment, a substrate 1b which is different from the substrate 1a essentially only differs in that the surface or finishing layer 9 multi-layered, consisting of one directly on the metallization 3 or on the metal areas 3.1 and 3.2 applied partial layer 9.1 from a heat-generating an oxide-forming metal, preferably nickel, and one of the sub-layer 9.1 covering outer layer of precious metal, preferably made of silver or gold. The layer thickness of the partial layer 9.1 For example, again in the range between 0.002 mm and 0.015 mm and the layer thickness of the sub-layer 9.2 of silver in the range between 0.00015 mm and 0.05 mm or the partial layer 9.2 gold between 0.0001 mm and 0.015 mm. When creating the solder stop pattern 5 by heat input diffuses the metal (nickel) of the sub-layer 9.1 the sub-layer 9.2 so that the solder stop pattern 5 again from the oxide of the metal of the sublayer 9.1 or substantially the oxide of the metal of the sub-layer 9.1 , For example, of nickel oxide (NiO) is formed, namely at a thickness of the sub-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 1b turn in such a way that after applying the metallizations 3 and 4 on the insulating layer 2 ( 14 ) and after structuring the metallization 3 ( 15 ) in two steps the ( 16 and 17 ) the partial layers are applied, for example galvanically and / or by chemical deposition and / or by spraying or cold gas spraying.

The connecting, and in particular the electrical connection of the substrate used in turn as printed circuit boards 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 generation of the at least one solder stop pattern 5 at the respective bond area 6 with the lot 7 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, so the laser treatment can in particular also be such that not only the material of the sub-layer 9.2 , but also the nickel of the sublayer 9.1 largely evaporated and thereby the solder stop pattern 5 as an oxide or oxide layer of the metal of the metallization 3 trains, z. B. as copper oxide or alumina.

As mentioned above, the generation of the solder stop pattern occurs 5 for example by laser radiation or laser treatment. The 21 shows a schematic representation of the laser treatment by means of a mask 11 , As a result, even with a laser beam A with a relatively large beam diameter by appropriate design of the mask 11 very fine structures for the respective solder stop pattern 5 be achieved.

The invention has been described above by means of exemplary embodiments. It is understood that numerous changes and modifications are possible, without thereby departing from the invention underlying the idea of the invention.

So it was assumed above that the solder stop pattern 5 be generated from the metal oxide by heat or heat input. In principle, there is also the possibility of the solder stop pattern 5 from the metal oxide by chemical and in particular wet-chemical oxidation using at least one mask and an oxidizing medium to produce, which medium is then applied by dipping and / or spraying through the mask used on the metallic surface of the substrate. Furthermore, in principle it is also possible to apply the oxidizing medium as a gel-like medium partially and along the stop pattern to be produced on the metallic surface of the substrate, for example by imprinting.

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

By a repeated, for example, twice, the solder stop pattern 5 a significant improvement in the soldering or barrier effect can be achieved.

Becomes the substrate 1 . 1a . 1b manufactured as a multiple use or as a multi-substrate and takes place in a laser treatment step, the separation of the multi-substrate in the substrates 1 . 1a . 1b or the introduction of Tenn- or predetermined breaking lines in the insulating layer 2 for severing the multi-substrate by breaking into the substrates 1 . 1a . 1b , so are preferred in this process step, but at least with the same laser at the same time also Lötstoppmuster 5 generated.

LIST OF REFERENCE NUMBERS

1, 1a-1c

substratum

2

insulating

3, 4

metallization

3.1, 3.2

metal sector

5

Solder stop pattern or structure

6

Bond area

7

solder

8th

electrical component

9

Surface or finishing layer

9.1, 9.2

sublayer

11

mask

A

Heat or heat input or laser radiation

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008042777 A1 [0003]
• US 3744120 [0004]
• DE 2319854 [0004]
• DE 2213115 [0006]
• EP 153618 A [0006]
• DE 4319944 A1 [0010]

Claims (19)

Substrate, in particular in the form of a 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 at least partially formed by a metal layer or metal foil metallization, and at least one at the metallization ( 3 . 4 ) and / or on a surface or finishing layer ( 9 ) formed bond area ( 6 ) limiting solder stop structure ( 5 ), wherein the solder stop structure ( 5 ) of a metallic oxide, preferably of a metallic oxide of the metallization ( 3 . 4 ) and / or of a metallic oxide of the surface or final layer applied to the metallization ( 9 ), characterized in that the solder stop structure ( 5 ) to the level of the adjacent exposed outer surface of the metallization ( 3 . 4 ) or the surface or finishing layer ( 9 ), preferably protruding above this level. Substrate according to claim 1, characterized in that the at least one metallization of a copper layer, preferably of a copper layer having a thickness in the range between 0.015 mm to 0.8 mm, or of a layer of aluminum, preferably with a thickness in the range between 0.015 mm to 0.8 mm, and that the oxide layer of an oxide of the metal of the metallization, preferably of a copper oxide having a thickness in the range between 0.00015 mm to 0.1 mm or of an aluminum oxide, preferably with a thickness in Range is formed between 0.005 mm to 0.1 mm. Substrate according to Claim 1 or 2, characterized in that, on top of the insulating layer ( 2 ) subsequent metallization ( 3 . 4 ), preferably in the form of a copper or aluminum layer, an at least single-layer surface or final layer ( 9 ) is applied, that the surface or final 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 .mu.m and 3 .mu.m, 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 .mu.m and 3 .mu.m , Substrate according to claim 3, characterized in that the surface or finishing layer ( 9 ) is made of a plurality of layers 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 which are adjacent to the insulating layer ( 2 ) side facing away from the nickel layer. Substrate according to claim 3 or 4, characterized in that the solder stop structure ( 5 ) forming oxide layer ( 5 ) essentially of a metal oxide of the surface or final layer ( 9 ), preferably of nickel oxide, and that the solder stop structure ( 5 ) oxide layer 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 ) the at least one soldering or bonding area ( 6 ) encloses. 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 ) made of plastic, for example made 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 ) is a ceramic layer, preferably 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 with the insulating layer ( 2 ) connected is. Substrate according to one of the preceding claims, characterized in that the at least one bonding or soldering region ( 6 ) a solder layer ( 7 ), wherein, for example, via the solder layer ( 7 ) a component ( 8th ) with the substrate ( 1 . 1a . 1b ) connected is. Method for producing a substrate ( 1 . 1a . 1b ), in particular in the form of a circuit board for electrical circuits and / or modules, with an insulating layer and with at least one at least single-layer metallization ( 3 . 4 ) on a surface side of the insulating layer ( 2 ) and with at least one at least solder stop structure ( 5 ), which has a bonding or soldering area ( 6 ) on the metallization ( 3 . 4 ) or on a surface or finishing layer ( 9 ) is at least partially limited, wherein the solder stop structure ( 5 ) by partial conversion of metal of the at least one metallization ( 3 . 4 ) and / or on the metallization ( 3 . 4 ) applied surface or finishing layer ( 9 ) is produced in an oxide or in an oxide layer, preferably after structuring the at least one Metallization ( 3 . 4 ), characterized in that the oxide or the oxide layer is produced without material removal. Method according to claim 10, characterized in that the partial transformation of the metal of the at least one metallization ( 3 . 4 ) and / or the surface or finishing layer ( 9 ) in which the solder stop structure ( 5 ) forming oxide by heat input and / or by chemical oxidation, for example by laser treatment, for. B. with a YAG or CO2 or Eximer laser, and / or by an oxidizing micro-flame. Method according to one of the preceding claims, characterized in that the partial conversion of the metal into the oxide forming the solder stop structure in an oxygen-containing atmosphere having 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 preceding claims, characterized in that the 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 transverse to this course. Method according to one of the preceding claims, characterized in that the solder stop structure ( 5 ) forming oxide layer ( 5 ) after application of an at least single-layer metallic surface or finishing layer ( 9 ) on the with the insulating layer ( 2 ) associated metallization ( 3 . 4 ), for example made of copper or aluminum, wherein the surface or outer layer ( 9 ) or at least one sub-layer ( 9.1 . 9.2 ) of this surface or finishing layer ( 9 ) made of nickel, gold, silver or at least two-layered formation of the surface or final layer ( 9 ) one to the metallization ( 3 . 4 ) subsequent first sub-layer ( 9.1 ) of nickel and another to the first sublayer ( 9.1 ) subsequent sub-layer ( 9.2 ) consists of silver and / or gold. A method according to claim 14, characterized in that the solder stop structure ( 5 ) forming oxide layer ( 5 ) exclusively or substantially exclusively of the metal of the surface or final layer ( 9 ) is produced. Method according to one of the preceding claims, characterized in that in the case of an insulating layer ( 2 ) made of ceramic, such as aluminum oxide, aluminum nitride, silicon nitride or aluminum oxide with zirconium oxide, the at least one of copper or aluminum existing metallization by DCB bonding or active soldering or by gluing, preferably by gluing with a carbon fiber or carbon nanofibers containing adhesive with the insulating layer ( 2 ), and / or that in the case of an insulating layer ( 2 ) of a polymeric material, the at least one metallization ( 3 . 4 ) with the insulating layer by gluing, preferably with a polymeric adhesive, for. B. is bonded to a polymeric carbon fiber and / or carbon nofasern containing adhesive. Method according to one of the preceding claims, characterized in that on the at least one bonding or soldering region ( 6 ) after generating the solder stop structure ( 5 ) a solder layer ( 7 ) and / or at least one electrical component ( 8th ) over the solder layer ( 7 ) with the substrate or the at least one metallization ( 3 . 4 ) or their surface or finishing layer ( 9 ) is connected. Method according to one of the preceding claims, characterized in that at least one metallization ( 3 . 4 ) as a pre-structured metal layer or metal foil or by thick-film technique and / or spraying on the insulating layer ( 2 ) is applied. Method according to one of the preceding claims, characterized in that when producing the substrates in a multiple use or in a multiple substrate and when separating the multiple substrate into the substrates ( 1 . 1a . 1b ) or when introducing separation or predetermined breaking lines 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 and the Lötstoppstrukturen or Lötstoppmuster ( 5 ) be generated.

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