DE102016001810A1 - Method for producing a printed circuit board with reinforced copper structure - Google Patents

Abstract

It is called a method for producing a multilayer printed circuit board with at least one in an inner layer reinforced track, at least one piece of an element conventionally prepared by etching copper structure conductor track by means of cold spraying technique (kinetic spraying or CDGS Cold Gas Dynamic Spraying) is formed reinforced and It is called a multilayer printed circuit board produced in this way and the application for wiring or electrical connection and for the mechanical attachment of electrical or electronic components.

Description

The invention relates to a method for producing a multilayer printed circuit board (multilayer) with conventionally prepared in etching copper structure (trace) and at least in an inner layer by means of cold gas spraying reinforced copper structure and a printed circuit board prepared in this way and the application as a printed circuit board.

Circuit boards, also referred to as Printed Circuit Boards (BCBs) or Printed Wiring Boards (PWBs) or printed circuit board or board or printed circuit are used for wiring or electrical connection and mechanical attachment of electrical or electronic components (el. el. Components), these el. Components can be fixed radially in holes of the circuit board and electrically contacted or can be mounted on the surface (surface mount technology SMT or surface mount devices SMD) or buried in inner layers (burried components).

On the one hand, the el. Components are becoming smaller and more complex, combined with a high heat output and thus the need to dissipate the heat loss of el. Components is always higher and on the other hand ever higher currents are provided or needed on relatively small PCB surfaces, such as in modern LED Elements of lighting technology or in the EV (Electro Vehicle) area or in general in power electronics. It is therefore necessary to dimension the copper cross sections of the wiring structures on and in printed circuit boards to the planned, higher currents so that the heating of the copper lines per se remains within planned limits. In other cases, copper structures are actively used to dissipate the heat loss of el. Components.

Conventional printed circuit board materials such as FR-4 consist of an electrically insulating epoxy resin-glass fiber fabric composite with copper foils arranged thereon, which are patterned by means of etching technology with the formation of conductor tracks.

For manufacturing reasons, the copper foils are very well bonded to the surface of the insulating epoxy-glass fiber fabric composite (FR-4), so that no delamination occurs during the production process of a multilayer and after the assembly of the printed circuit board with electronic components, they are mechanically well held by the structured copper surfaces can be.

In order to be able to conduct high currents or to be able to dissipate high thermal loads, the copper thicknesses of typically 9, 12, 18, 35, 70, 105 μm thickness are increased to 140 μm and 210 μm and 400 μm to over 1,000 μm thickness. This thickening of the copper structures can according to the prior art galvanic / chemical or by the use of thick copper profiles (so-called. Coins) or by the application of thick copper elements with z. B. ultrasound.

The EP1365637A2 describes a printed circuit board in the form of ceramic materials. However, the adhesion properties of copper interconnects on ceramic substrates are insufficient and can only be improved with great effort.

In the WO2005053367A2 For example, a Cold Gas Dynamic Spraying (CGDS) spray method is disclosed which does not, however, show the increase in trace thickness of a copper trace.

In the WO2013158178A2 describes a micro cold spray direct-write system, however, with the no trace structures can be improved.

In the WO2014102054A1 a conductor track arrangement is described with oblique edges, but does not show a subsequent amplification of printed conductor structures produced in the etching process.

All these known methods have turned out to be disadvantageous because the creation of printed conductors with increased thickness (height), which goes beyond the thickness (height) of the printed conductors produced in etching technology, is associated with great expense.

The invention is therefore based on the object to form a printed circuit board produced in conventional etching with exposed by a conventional etching conductor tracks made of copper so that with little effort, the thickness (height) of the tracks can be increased.

To solve the problem, the invention is characterized by the technical teaching of claim 1.

According to the invention, it is proposed to reinforce desired copper structures-preferably-in inner layers of a multilayer printed circuit board by means of the so-called cold gas spraying technique (kinetic spraying or CDGS cold gas dynamic spraying).

Cold gas spraying is a coating process in which the coating material is applied in powder form to the carrier material (substrate) at very high speed. To is accelerated to a few hundred degrees heated process gas by expansion in a Laval nozzle to supersonic speed and then injected the powder particles in the gas jet. The injected spray particles are thereby accelerated to such a high speed that, in contrast to other thermal spraying methods, they form a dense and firmly adhering layer upon impact with the substrate even without prior melting or melting. The kinetic energy at the time of impact is generally insufficient for complete melting of the particles.

In this case, copper particles or else copper alloy particles are accelerated and finely focused in a gas jet such that a further high-density copper layer is formed on the existing printed conductor structure. It is therefore an application method with which the thickness of the printed conductors produced in etching technology can be substantially increased.

In addition to the cold gas spraying application method described above, the invention generally also claims the methods of thermal spraying as a surface coating method specifically only for thickness application of copper conductor tracks.

According to the normative definition ( DIN EN 657 ) filler materials, the so-called spray additives, inside or outside of a spray burner off, on or melted, accelerated in a gas stream in the form of spray particles and thrown onto the surface of the component to be coated. The component surface is not melted (in contrast to build-up welding) and only subjected to a low thermal load.

A layer formation takes place because the spray particles flatten more or less depending on the process and material when hitting the component surface, stick primarily by mechanical clamping and layer by layer build up the spray layer. Quality features of sprayed coatings are low porosity, good adhesion to the component, freedom from cracks and homogeneous microstructure. The achieved coating properties are significantly influenced by the temperature and the speed of the spray particles at the time of their impact on the surface to be coated. The surface condition (purity, activation, temperature) also has a significant influence on quality features such as adhesion.

As an energy source for the on or melting of the spray additive used electric arc (arc spraying), plasma jet (plasma spraying), fuel-oxygen flame or fuel-oxygen high-speed flame (conventional and high-speed flame spraying), fast, preheated gases (cold gas spraying) and Laser beam (laser beam spraying). Loud DIN standard EN 657 the spraying processes are classified according to these criteria.

The purpose of these methods is the targeted coating of the copper conductor tracks produced by etching technology for the purpose of altering and specifically adapting surface properties.

This has the advantage that the favorable properties - in particular their adhesion properties on the printed circuit board - of the printed conductors produced in an etching technique on a FR-4 printed circuit board are maintained. This highlights the method according to the invention over the known methods.

In the known methods had suitable thick copper profiles z. B. are determined by ultrasonic welding on the surface of a FR-4 circuit board. Thus, only insufficient adhesion properties of the thick copper profiles on the surface of the plastic circuit board could be achieved. As the need arises to electrically contact an increasing number of components on the trace cross-sections, there is a disadvantage in the prior art of reduced adhesion of the thick copper profiles to the printed circuit board surface when loaded with a variety of devices.

The load transfer properties of the thick copper profiles produced in conventional technology on the surface of the printed circuit board were therefore insufficient.

This is where the invention begins, in which the well-known adhesion properties of conductor tracks produced in etching technology are used in order to selectively generate a conductive conductive structure consisting of copper particles, which increases the height (thickness) of the conductor track, but the good load transfer properties of such Maintains trace opposite the carrier plate.

Advantage of the method according to the invention is that only selectively, selected individual tracks in their thickness (height) can be increased. The conductive spray application should be sharp with the thickness of the existing tracks. It should therefore be a thickness structure (in the vertical direction), that is, in the vertical extent of the existing interconnect structure.

Of course, however, the invention can provide an increase in the width of the conductor track and / or an increase in the conductor track height.

Another advantage of the method according to the invention is that it is provided in a first embodiment that the sprayed thickness profile is uniformly high for all laterally treated printed conductors.

In another embodiment, it may be provided that the thickness profile is uneven. Some tracks can subsequently have a greater thickness (height), as compared to other tracks. Some traces may also remain untreated and retain their original trace thickness made by etching.

Finally, the thickness profile can also be modulated over a certain length of a conductor track. Therefore, a higher order can take place on a first length section of such a conductor path than on a different length section of the same conductor track.

Incidentally, the invention is not limited to reinforcing the printed conductors of the inner layers of a multilayer printed circuit board by the application method according to the invention. The method can be used for all printed conductors of single or multilayer printed circuit board.

In principle, the surface of the copper structure and / or the gas and / or the copper particles can be preheated.

After the spray application has taken place, in the case of a multilayer printed circuit board, the interconnects located in inner layers can be densified by the subsequent laminating process and thus solidification of the applied interconnect structure.

The invention accordingly relates to a method for producing a multilayer printed circuit board having at least one conductor track reinforced in an inner layer, wherein at least one piece of an element of a copper structure printed circuit trace (cf. 4 ) is formed reinforced by means of cold gas spraying (kinetic spraying or CDGS Cold Gas Dynamic Spraying).

It is preferred if the gain results in at least a doubling of the copper structure layer thickness.

It is further preferred if the reinforcement of the copper structure layer thickness results in a total layer thickness of greater than 200 μm, in particular greater than 400 μm to more than 1000 μm.

According to a preferred feature, a method is used which performs the reinforcement by means of cold gas spraying with copper or copper alloy particles. In such a cold spraying process, the conductive particles shot at high speed onto the printed circuit board side wiring pattern are fixedly bonded to the upper surface of the wiring board side wiring pattern. Such is to be compared with a cold friction welding process or a kneading process, in which the applied particles give a permanent bond with the copper of the conductor track.

It is possible to prepare the surface of the track coated with the particles especially for the attachment of the particles. For this purpose, it is provided to roughen the surface chemically or mechanically or to scratch or to produce a chemical or mechanical treatment carried out improving the adhesion of the surface of the conductor track.

It is preferred if the copper or copper alloy particles have a size distribution of d50 of a few micrometers or submicrons and have a spherical shape, a platelike or rod-shaped or conical shape.

Thus, a particularly good entanglement of the applied particles can be achieved with each other, so that a homogeneous structure of the applied conductor track structure results, the conductivity of which corresponds to the conductivity of the underlying trace structure. The applied layer thus combines homogeneously with the conductor track structure located on the surface of the printed circuit board.

Further, the copper or copper alloy particles may be selected to be in the micrometer and / or submicron and / or nanoscale dimensions, and a very narrow (monomodal) or wide Gaussian distribution, or a bimodal or multimodal distribution may be used.

The copper or copper alloy particles may be further coated, e.g. With silver. In this case, a very small layer thickness in the nanometer range can be selected. They then have a core of copper and a shell of another, suitable material z. B. Ag or Au.

The subject of the present invention results not only from the subject matter of the individual claims, but also from the combination of the individual claims with each other.

All information disclosed in the documents, including the abstract, and Features, in particular the spatial design shown in the drawings, are claimed as essential to the invention, as far as they are new individually or in combination with respect to the prior art.

In the following, the invention will be explained in more detail with reference to drawings illustrating several execution paths. Here are from the drawings and their description further features essential to the invention and advantages of the invention.

Show it:

1 : a schematic section through a substrate ( 3 ) with a structured copper structure trace ( 4 ) and arranged thereon reinforced track ( 7 ) and the cold gas spraying system ( 2 ).

2 FIG. 2: a schematic section through a multilayer printed circuit board (FIG. 1 ) with a reinforced track ( 7 ) on a copper structure trace ( 4 ).

In 1 is a schematic section through a substrate ( 3 ) with a structured copper structure trace ( 4 ) and arranged thereon reinforced track ( 7 ) and the cold gas spraying system ( 2 ). The substrate ( 3 ) may be inner layer or outer layer or prepreg or from a base material such. FR-4 Low Tg, FR-4 High Tg, FR-2, FR-3, CEM-1, XEM-x, PI, CE or aramid.

A preferred base material is FR-4, an epoxy glassy braided fabric which is a FR-4 prepreg having a typical thickness of 78 μm (e.g., Type 1080) or 120 μm (e.g., Type 2116) or 180 μm (e.g. B. Type 7628) or 60 μm (eg Type 106) or 100 μm (eg Type 2125) or 125 μm (eg Type 2165) etc. is available.

Furthermore, such FR-4 prepregs are available in a standard version with a Tg of greater than 135 ° C or in the form of High-Tg at 170 ° C to over 180 ° C. Tg denotes the glass transition temperature. Prepregs with two pre-pressed copper layers are referred to as core layers (cores).

The thickness of the copper layers or copper foils are i. a. 12, 18, 35, 70, 105 microns and can be in thick copper 140 microns or 210 microns to 400 microns. Quite essential for the use of prepregs which are pressed with copper layers, their adhesion and the value determined in a peel test (peel test), the i. a. must be in the range of greater than 1.1 to 1.6 N / mm and even after a climatic test of 24 hours at 85 ° C and 85% relative humidity has no significant change.

The copper layers are photolithographically structured and etched in accordance with the state of the art, and result in structured printed conductors ( 4 . 15 ).

According to the invention, piecewise copper structure printed conductors ( 4 ) by means of cold gas spraying ( 2 ) strengthened. So it becomes a copper structure ( 4 ) as a document for reinforcement ( 7 ) and not the insulating substrate material ( 3 ), ia epoxy glass hard tissue. Thickness should be as sharp as possible, so that the original width of the conductor is not or only slightly increased.

In order to avoid undesirable edge effects, that is, to prevent the sprayed-on particles from getting into the vicinity of the conductor track to be coated, provision may be made for the plastic surface of the printed circuit board to be coated in the vicinity of the conductor track to be coated with a release agent (eg. Silicone or blue or pink peel-off lacquer) to remove any unwanted application of the particles sprayed and deposited adjacent to the trace by subsequent mechanical brushing or chemical etching.

Likewise, a congruent with the edge of the conductor to be coated interconnect, coating of the conductor can be achieved in that with the spray nozzle a longitudinally extending aperture is carried, which ensures a targeted coating of the conductor in the longitudinal direction, but one on the lateral edge of the Conduit beyond going coating avoids.

The boundary layer arranged on the upper side of the strip to be coated ( 19 ) is thus responsible for the liability of the reinforcement ( 7 ) on the copper structure ( 4 ) and of course for the electrical and thermal conductivity between the two layers ( 4 . 7 ).

The aim is an intermetallic compound. For this reason, the deoxidation of the surface of the copper structure ( 4 ) substantially, on the one hand according to the state of the art in the printed circuit board industry by means of brushes or pimples with dilute etching solution (microetching) or by means of plasma treatment. It is essential that the shortest possible residence times between the surface treatment and the cold gas spraying process are complied with in order to avoid unwanted oxidation.

The cold gas spraying process with the cold gas spraying system ( 2 ) takes place by supplying a gas ( 6 ) and the supply of metallic electrically conductive particles ( 5 ) and the desired fine Focusing by a suitably designed nozzle system of the accelerated particle beam ( 8th ) on the copper structure ( 4 ) for forming the reinforced copper structure ( 7 ).

As gas ( 6 ) dry air or preferably inert gas such as nitrogen or argon can be used and the gas ( 6 ) can be used preheated to about 260 ° C.

The temperature of the surface of the copper structure ( 4 ) may be room temperature or it may be selectively preheated to about 180 ° C locally or totally and it may also be the entire substrate ( 3 ) are used preheated to 180 ° C, I prefer over 160 ° C.

The cold gas spraying process can be carried out under atmospheric air or under an inert gas such as nitrogen or argon.

The jet pressure of the gas can in the high pressure range of z. B. 750 PSI = 51.7 bar or in the low pressure range of z. B. 6 bar. All intervening pressure ranges are also recognized as advantageous.

The Laval nozzles which are preferably used have the property of accelerating the fluid to supersonic speed from a convergent and then divergent flow cross section without resulting in excessive compression impacts;
In many cases, however, the generation of a supersonic speed is not necessary.

In the printed circuit board industry, strip conductors are used almost exclusively of copper, whereby the free copper surfaces of the outer layers are passivated in organic or inorganic form and remain solderable for months. In particular, the inorganic passivation with a thin nickel-silver layer is very well suited for the connection of the copper or copper alloy particles by means of cold gas spraying, but this increases costs are given.

As metallic electrically conductive particles ( 5 ) copper particles or copper alloy particles are used. The particle shape can be chosen to be spherical or platelike or rod-like or cone-like or crystalline-random, with spherical particles preferably being used.

The size distribution of the particles used ( 5 ) can be selected in the micrometer range to about 30 microns or submicrometer or in the nanoscale range, the size distribution can be selected according to a Gauss distribution. It is also possible to use monomodal or bimodal or multimodal particle size mixtures. In particular, small amounts of nanoscale copper or silver or palladium particles in the range of 0.1 to 3.0 wt.% May be incorporated and thus reduce the sintering temperature without increasing the cost too much.

Furthermore, copper alloys with admixtures of zinc (Zn) and / or silver (Ag) and / or magnesium (Mg) and / or nickel (Ni) and / or iron (Fe) and / or manganese (Mn) and / or tin ( Sb) and / or aluminum (Al) are selected and thus the properties of the reinforced track ( 7 ).

It is also possible to use the copper and copper alloy particles ( 5 ) are formed coated. In a preferred embodiment, the particles are microencapsulated with a nanoscale silver layer and are thereby passivated and facilitate or improve the intermetallic bond between the layers to be joined and / or reduce the sintering temperature.

The copper or copper alloy particles ( 5 ) can be used preheated to about 260 ° C.

The reinforced copper structure ( 7 ) is coated with a thickness of at least the thickness of the copper structure trace ( 4 ), but in particular much thicker in the range of greater than 200 microns to over 400 microns and up to over 1,000 microns, and can in this way conduct such high electrical currents that were not achievable with previous conductor tracks produced in etching.

The reinforced copper structure therefore also has very good thermal properties. The porosity is better than 97% and in particular better than 99%.

As the thickness of the substrate ( 3 ) and the copper structure ( 4 ) are thinner than the thickness of the reinforced track ( 7 ) can lead to distortions or unevenness, which can adversely affect subsequent processing. In such a case, it may be advantageous to use the semifinished product consisting of the substrate ( 3 ) with the copper structure ( 4 ) and the reinforcement ( 7 ) or the other copper structures ( 15 ) to calender, so to move by a roller assembly to achieve in this way a required flatness.

In 2 is a schematic section through a multilayer printed circuit board ( 1 ) with a reinforced track ( 7 ) on a copper structure trace ( 4 ) on an inner layer substrate ( 3 ).

In this exemplary illustration, a total of 6 interconnect copper layers ( 13 . 14 . 15 . 16 . 17 . 18 ), wherein the copper layer ( 15 ) the copper structure ( 4 ), on which a reinforcement ( 7 ) is arranged.

By way of example, schematically another via ( 12 ) and is schematically the solder mask above ( 20 ) and below ( 21 ).

Furthermore, two outer layers ( 9 ). The location ( 3 ) is shown as a core layer, the two inner layers ( 10 . 11 ), wherein the inner layer ( 10 ) in the area of the reinforced track ( 7 ) is made recessed, so with recesses in the area of the reinforced track structure ( 7 ) is carried out, thus enabling a homogeneous lamination during the lamination process.

This schematic representation of a multilayer printed circuit board ( 1 ) is shown only as an example. It can determine the number of copper layers ( 13 . 14 . 15 . 16 . 17 . 18 ) and several reinforcements ( 7 ) are arranged in inner layers.

LIST OF REFERENCE NUMBERS

1

Multilayer PCB (Multilayer - ML)

2

Cold gas spraying system (cold gas dynamic spray CGDS system)

3

Substrate: inner layer or prepreg or base material such. FR-4 Low Tg, FR-4 High Tg, Gr-2, FR-3, CEM-1, XEM-x, PI, CE, Aramid

4

Copper structure trace: i. a. Etched copper with a thickness of 12 or 18 or 35 or 70 or 105 μm with an adhesion to the substrate of greater than 1.1 N / mm to 1.6 N / mm

5

Metallic electrically conductive particles, in particular copper particles or copper alloy particles with various shapes and size distributions (Gaussian distribution bzm. Monomodale or Eimodale or multimodal distribution) and nano-coatings and admixtures such as nanoscale copper and / or silver or Palldaiumteilchen.

6

Gas: air or, in particular, inert gases such as nitrogen or argon

7

Reinforced track

8th

particle

9

backsheet

10

Inner layer over the reinforced copper structure

11

inner layer

12

via

13

Copper layer 1

14

Copper layer 2

15

Copper layer 3

16

Copper layer 4

17

Copper layer 5

18

Copper layer 6

19

interface

20

Solder mask on top

21

Solder mask below

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

• EP 1365637 A2 [0007]
• WO 2005053367 A2 [0008]
• WO 2013158178 A2 [0009]
• WO 2014102054 A1 [0010]

Cited non-patent literature

• DIN EN 657 [0018]
• DIN standard EN 657 [0020]

Claims (26)

Method for producing a multilayer printed circuit board ( 1 ) with at least one copper structure conductor track produced by etching technology in an inner layer ( 4 ), characterized in that a conductive thickening of the copper structure trace ( 4 ) by at least piecewise coating by means of thermal spraying. A method according to claim 1, characterized in that the coating method of thermal spraying is carried out either as cold gas spraying or as thermal spraying. A method according to claim 1 or 2, characterized in that the cold gas spraying technique kinetic spraying and / or a. CDGS Cold Gas Dynamic Spraying ( 2 ). Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 3, characterized in that the reinforcement results in at least a doubling of the copper structure layer thickness. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 4, characterized in that the reinforcement of the copper structure layer thickness results in a total layer thickness of greater than 200 μm, in particular greater than 400 μm to more than 1,000 μm. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 5, characterized in that the reinforcement is carried out by means of cold gas spraying with copper or copper alloy particles. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 6, characterized in that the copper or copper alloy particles have a size distribution bezgl. d50 of a few micrometers or submicrons and have a spherical shape, a platelike or rod-shaped or conical shape. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 7, characterized in that the copper or copper alloy particles have a nanoscale silver coating. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 8, characterized in that the copper or copper alloy particles are used in a multimodal, in particular bimodal particle distribution, wherein the average diameter d50 in the ratio 1: 2 to 1:20 is used. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 9, characterized in that nanoscale copper and / or silver and / or palladium particles in the range from 0.1 to 3.0% by weight are added to the copper or copper alloy particles become. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 10, characterized in that an inert gas such as nitrogen or argon is used in the cold gas spraying technique. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 11, characterized in that the cold gas spraying technique is performed on the copper-structured printed circuit board substrate in an inert gas atmosphere. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 12, characterized in that the copper-structured printed circuit board substrate is coated at room temperature. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 13, characterized in that the copper-structured printed circuit substrate is heated to 180 ° C coated. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 14, characterized in that only the copper structure of the printed circuit board substrate is heated to 180 ° C is coated. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 15, characterized in that the gas stream of the cold gas spraying plant is heated to 260 ° C is used. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 16, characterized in that the gas-borne copper or copper alloy particles are heated to 260 ° C. Method for producing a multilayer printed circuit board ( 1 ) according to one of Claims 1 to 17, characterized in that the copper-structured substrate, which is reinforced by means of cold gas spraying, is subjected to a calendering process and is then pressed by means of a printed circuit board lamination system into a multilayer printed circuit board. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 18, characterized in that the reinforced copper gas spraying technique formed by the copper structure has a porosity better than 97% and in particular better than 99%. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 19, characterized in that the at least one by cold gas spraying reinforced copper structure formed on an inner layer with a correspondingly structured recessed inner layer (spacer layer or one or preferably several prepregs with recesses) with a PCB laminating to a multilayer printed circuit board is pressed. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 20, characterized in that the copper structure of the printed circuit board substrate is deoxidized before the cold gas spraying process. Method for producing a multilayer printed circuit board ( 1 ) according to one of claims 1 to 21, characterized in that the copper structure of the printed circuit board substrate is plasma treated prior to the cold gas spraying process. Multi-layer printed circuit board ( 1 ) with at least one in an inner layer by means of cold gas spraying reinforced copper structure prepared according to one of claims 1 to 20. Application of the multilayer printed circuit board ( 1 ) according to claim 23 for the wiring or electrical connection and for the mechanical fastening of electrical or electronic components. Device for thickness coating of a conductor track structure, which was created by etching on a plastic composite materials printed circuit board, characterized by a cold gas injection nozzle ( 2 ), which by supplying a gas ( 6 ) and the supply of metallic electrically conductive particles ( 5 ) an accelerated particle beam ( 8th ) on the copper structure ( 4 ) for attaching the reinforced copper structure ( 7 ). Apparatus according to claim 25 for carrying out the method according to at least one of the claims 1 to 21, characterized in that the web guide of the cold gas spraying nozzle ( 2 ) is synchronized in the manner of an X-Y feed system with the web guide of the printed conductors to be coated or that the interconnects to be coated are movable with an X-Y feed system under the fixed cold gas spray nozzle or the web guide of the cold gas spraying nozzle ( 2 ) in X- and to be coated interconnects in the Y direction or vice versa.

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