DE102008024885A1 - Printed circuit board manufacturing method, involves applying additional layer on base layer, and merging connection layer with base layer and with metallic powder layer to form double layer - Google Patents

Abstract

The method involves selective melting of defined areas within a metallic powder layer by energy supply, and removing unmelted metallic powders. A layer consisting of insulating material (5) is applied, where a base layer (6) with a conductive path plane (2c) is produced on a working surface (3). An additional layer (6a) is applied on the base layer for forming a double layer (7), where a printed circuit board (1) is formed with a conductive path plane (2b). A connection layer (8) is merged with the base layer and with the metallic powder layer to form the double layer. An independent claim is also included for a device for producing a printed circuit board with two conductive path planes.

Description

The The invention relates to a method and a device for Production of printed circuit boards.

From the DE 196 48 080 A1 is a method for producing conductor tracks containing 3D-MID prototype parts (3-dimensional molded interconnect device) is known, wherein the rapid prototyping method for generating a master model of the conductor geometry is used. This master model is duplicated in a silicone rubber mold by vacuum casting. The duplicated trace geometries are placed in a second silicone rubber mold wherein the prototype part is completed in the vacuum casting process.

A disadvantage of in the DE 196 48 080 A1 described method is that for the production of conductive 3D-MID prototype parts in addition to the rapid prototyping process even the complex vacuum casting process is used. Furthermore, it is unfavorable that the conductor track geometry produced by means of the mentioned method can only be integrated into a polyurethane substrate.

The document EP 1 347 853 B1 describes a method and apparatus for making a three-dimensional metal part using high temperature direct laser melting devices.

One Disadvantage of this method and this device is in their limited application, according to which the metal part produced has a homogeneous composition of only one type of metal, where no other component, such as a non-conductive Substrate is provided.

From the WO 2004/076102 shows a method and an apparatus for producing a three-dimensional object. The three-dimensional object is formed by irradiating a powder layer of an inorganic or organic powder material with an optical beam to form a sintered layer and laminating these sintered layers.

Also that produced by this method or by means of this device Object consists of only one material, namely many Layers made either from the sintering of inorganic or from the sintering of organic powders. Unfortunately, can by means of the specified method no second material within a layer to be sintered, so that the cross section by the generated three-dimensional object only a homogeneous Area corresponds, which was made of a single material.

It the task results in a conductive multi-layer system to create, which by means of a suitable method and a corresponding device for the layered structure of the multilayer system at least two different components firmly together.

In terms of of the method, the object is achieved according to the invention by the features of claim 1. Advantageous developments are the subject of the dependent claims.

• – selektives Schmelzen definierter Bereiche innerhalb der Metallpulverschicht mittels Energiezufuhr
• – Entfernung von nicht geschmolzenen Metallpulver
• – Auftrag einer weiteren Schicht bestehend aus Isoliermaterial, wobei auf der Arbeitsfläche eine Basisschicht mit einer Leiterbahnebene erzeugt wird. Auf dieser Basisschicht wird mindestens eine weitere Schicht aufgetragen, die mindestens eine Doppelschicht und somit eine Leiterplatte mit mindestens einer zweiten Leiterbahnebene bildet, wobei eine zuvor aufgetragene Verbindungsschicht mit der darunterliegenden Basisschicht sowie mit einer auf der Verbindungsschicht aufgetragenen Metallpulverschicht zu einer Doppelschicht verschmolzen wird.

Claim 1 describes a method for producing a printed circuit board having at least two printed circuit traces starting from a first metal powder layer on a work surface, the method comprising the following steps:

• Selective melting of defined regions within the metal powder layer by means of energy supply
• - Removal of unmelted metal powder
• - Order a further layer consisting of insulating material, wherein on the work surface, a base layer is produced with a conductor track plane. At least one further layer is applied to this base layer, which forms at least one double layer and thus a printed circuit board with at least one second printed circuit trace layer, wherein a previously applied bonding layer is fused to the underlying base layer and to a metal powder layer applied to the bonding layer to form a double layer.

advantageously, becomes the position of the work surface after each merge process changed so that the layers are targeted can.

The particular advantages of the invention are that only one operation on a machine or on a suitable Device is necessary. This work involves several steps, where advantageously several material components, in common used with powdered metal even within a layer can be, whereby a common sintering different Layers with a laser beam is guaranteed.

The inventive method is advantageous because the circuit board can be made directly in one operation, ie on a machine, and since the inventive method ensures a higher precision. In particular, the method according to the invention makes it more advantageous prevents the circuit traces are undercut, since the inventive method dispenses with etching processes.

Of Further, it is advantageous if in the inventive Method, the energy is supplied by means of a laser beam, because the output power of a laser is easily adjustable and thus to those necessary for sintering of the various layers Energy can be adjusted quickly.

moreover it is advantageous if in the inventive Method of laser beam on the basis of CAD data line by line the layers are controlled, which are on the work surface to be generated. This ensures that the means produced by the process according to the invention Product or prototype for further developments or Tests are available quickly.

Further can use the CAD data vias and breakthroughs or holes with freely selectable cross-section quickly and easily to be generated.

Furthermore It is advantageous if the work surface is over a controller is moved vertically down or up, so that the layer to be processed lies in the plane which is from the Laser beam is scanned line by line for sintering.

One Another advantage is that the insulating material in powder form is present. This can create thin layers which are effectively fused by means of a laser beam or to be sintered. As an insulating material is advantageously Glass, ceramic or plastic used to some mechanical Properties such as flexural strength, heat resistance etc. to ensure.

Furthermore it is advantageous if as a connecting layer powdery Lot in particular glass solder, is used, so that the sintered Metal layer reliable with the sintered insulating layer is connected.

Also a powdered hotmelt adhesive can advantageously be used to connect the two different layers.

advantageously, The first metal powder layer becomes uniform applied thickly to the work surface and then merged into a solid base layer. This is a stable basis guaranteed for the further layers.

From Advantage is also, if the first, directly on the work surface Overlying base layer is a metal foil. This is advantageous already specified a trace course in the first interconnect level.

Further It is cheap if the first one, directly on the work surface resting base layer is a non-conductive substrate. Thereby is also a stable base for the further layers where.

From Another advantage is that the inventive method requires a relatively short machine runtime, since the component height of printed circuit boards is low.

The inventive method is due to said Advantages of an economical process, especially for the prototype production.

In terms of the device, the object is achieved according to the invention by the features of claim 12. Advantageous developments of inventive device are the subject the dependent claims.

The inventive device for producing a Printed circuit board with at least two printed circuit layers comprises a fusion unit for selective melting and a means of removal of not molten metal powder and an application unit for application another layer of a powdery insulating material. These are on a base layer applied to the work surface several layers provided with at least one second conductor track level. One layer at a time merges selectively on the solid base layer applied compound layer with a on this applied powdery layer.

One Advantage of the device according to the invention exists in that the fusion unit is a controllable laser device having. This allows certain selected Areas of a surface selectively with the underlying Layer are merged.

Further is advantageous if the device according to the invention a merge unit with a data interface for Has CAD data. The CAD data cause the laser device controlled line by line over the uppermost layer to be generated with areas defined by the CAD data, selectively fused with the underlying layer.

Furthermore it is beneficial if for the work surface a vertically movable work table is provided. Thereby can already finished layers below the plane in which the Laser works, be moved.

advantageously, is in the device according to the invention a uniformly thick application of the first metal powder layer on the work surface and a merger provided. The simultaneous fusion with the lower layer causes a Time savings in the production of the inventive Multilayer system.

following an embodiment of the invention with reference to a Drawing explained in more detail. Show in it

1 a detailed view of a bore in a multi-layer system according to the invention;

2 a novel multilayer system in a schematic representation and

3 an inventive device for the production of printed circuit boards.

each other corresponding parts are in all figures with the same reference numerals Mistake.

• – Definierte Bereiche werden innerhalb der Metallpulverschicht 4 mittels Energiezufuhr selektiv miteinander verschmolzen.
• – Nicht geschmolzenes Metallpulver, d. h. Metallpulver außerhalb der definierten Bereiche, wird entfernt.
• – Eine weitere Schicht bestehend aus Isoliermaterial 5 wird aufgetragen, wobei auf der Arbeitsfläche 3 eine Basisschicht 6 mit einer Leiterbahnebene 2c erzeugt wird, und wobei auf dieser Basisschicht 6 mindestens eine weitere Schicht 6a aufgetragen wird, die innerhalb der Leiterplatte 1 eine Doppelschicht 7 mit mindestens einer zweiten Leiterbahnebene 2b bildet. Dabei wird eine zuvor aufgetragene Verbindungsschicht 8 mit der darunterliegenden Basisschicht 6 sowie mit einer auf der Verbindungsschicht 8 aufgetragenen Metallpulverschicht 4 zu der Doppelschicht 7 verschmolzen. Die Position der Arbeitsfläche 3 wird nach jedem Verschmelzungsprozess verändert, indem die Arbeitsfläche 3 vertikal nach unten versenkt wird.

1 shows a detailed view of a hole 21 in a multi-layer system according to the invention 19 without curvature in a schematic representation. The multilayer system according to the invention is 19 by means of the method according to the invention for producing a printed circuit board 1 with at least two tracks 2a . 2 B . 2c , generated. This is based on a first metal powder layer 4 on a work surface 3 , and includes the following steps:

• - Defined areas are within the metal powder layer 4 selectively fused together by means of energy supply.
• Unmelted metal powder, ie metal powder outside the defined areas, is removed.
• - Another layer consisting of insulating material 5 is applied, taking on the work surface 3 a base layer 6 with a track plane 2c is generated, and wherein on this base layer 6 at least one more layer 6a is applied inside the circuit board 1 a double layer 7 with at least one second interconnect level 2 B forms. This is a previously applied compound layer 8th with the underlying base layer 6 as well as with one on the tie layer 8th applied metal powder layer 4 to the double layer 7 merged. The position of the work surface 3 is changed after each merge process by the workspace 3 vertically sunk down.

The energy supply for selective fusion takes place by means of a laser beam 9 , which is adjustable in intensity. The laser beam 9 is using the CAD data line by line across the layers 10 controlled, which on the work surface 3 or on the base layer 6 or on the other layers 6a to be generated.

Furthermore, the work surface 3 moved vertically downwards or upwards, this also based on control data or via a control unit 20 is controlled.

As insulating material 5 is used powdered glass or powdered ceramic or a plastic granules. For connecting the insulating material 5 with the metal powder layer 4 is in a first embodiment of the method according to the invention powdered solder, such as a suitable glass solder, z. B. gallium solder used. Gallium solders containing indium and copper can be soldered well above 100 ° C with a glass layer.

Further Glass-to-metal connections are also possible by using enamel. A paste of enamel is applied to the layers to be bonded and then heated. It is advantageous that when connected with enamel inner tensions and too strong Oxidation of the metal can be prevented. Furthermore, connections with Enamel vacuum-tight.

A second embodiment of the method according to the invention assumes that as the connecting layer 8th powdered hot melt adhesive, such as powdered epoxy resin adhesive is used.

According to the invention, the first metal powder layer 4 evenly thick on the work surface 3 applied and then to a solid base layer 6 merged.

The third embodiment of the method according to the invention assumes that the first, directly on the work surface 3 resting base layer 6 a metal foil is. On this metal foil are the other layers 10 applied and fused together, with the possibility that the complete interconnect layer is made by full-surface bonding of the metal foil, wherein the adhesive layer can be applied as a powder or the metal foil is precoated with an adhesive layer. In this case, the metal foil z. B. rolled with a hot roll and then the contours of the trace are generated by laser cutting.

The fourth embodiment of the method according to the invention extends to the fact that the first, directly on the work surface 3 resting base layer 6 a non-conductive substrate 11 is on which the other layers 10 applied and fused together, the position of the work surface 3 is lowered after each merge step down.

A fifth embodiment of the method according to the invention relates to the production of a printed circuit board 1 with a gradient layer, wherein the process-induced influence on the porosity of the layers produced. As a result, the solder or the adhesive particles can fill up the existing cavities during the fusion, with small connecting points being formed from solder, which produce a positive connection. For this purpose, the structure of the insulation layers 5 in the area of the respective connecting layers 8th the powder of insulating material, another powder, which consists of solder particles or adhesive particles mixed. By building the connection layer 8th The proportion of solder in each layer can be changed from several layers, resulting in a gradient layer whose proportion of solder is approximately 80-100% in the immediate vicinity of the metal layer or to the conductor track plane 2a . 2 B . 2c is highest.

If Ceramics used as insulating material, in addition to the glass solder also soft solder, d. H. z. B. tin solder with flux, second Powder can be used. Alternatively, the conductor can be layered made up of 100% soft solder, based on the use is dispensed with copper powder.

If Plastic is used as insulating material, the second powder portion made of epoxy resin adhesive, d. H. consist of hot melt adhesive.

2 shows a multilayer system produced by the method according to the invention 19 in an enlarged, schematic representation, wherein the brightly illustrated connecting layers 8th are clearly recognizable.

3 shows a device according to the invention 1a for the production of printed circuit boards 1 , The device according to the invention 1a comprises a device for selective melting 12 and a facility 13 for removing unmelted metal powder and an applicator unit 14 for applying a further layer of powdered insulating material 5 , Doing so are on one on the work surface 3 applied base layer 6 multiple layers 10 with at least one second interconnect level 2 B intended. The device according to the invention 1a includes a merger unit 15 to merge one on the solid base layer 6 applied powdery compound layer 8th with a powdered metal layer applied thereto 4 ,

The device according to the invention has a fusion unit 15 with a controllable laser device 16 and with a data interface for CAD data. The CAD data controls the laser device 16 line by line over the uppermost layer to be generated 18 ,

According to the invention is in the device 1a for the work surface 3 a vertically movable work table 17 intended.

The Invention is not limited to the embodiment shown in the drawing, especially not limited to printed circuit boards, but generally refers to the layered production of three-dimensional Obiekten, the Obiekte consist of more than one material. All features described above and shown in the drawing can be combined with each other.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19648080 A1 [0002, 0003]
• - EP 1347853 B1 [0004]
• WO 2004/076102 [0006]

Claims (17)

Method for producing a printed circuit board ( 1 ) with at least two tracks ( 2a . 2 B . 2c ) starting from a first metal powder layer ( 4 ) on a work surface ( 3 ), the method comprising the following steps: selective melting of defined regions within the metal powder layer ( 4 ) by means of energy supply - removal of unmelted metal powder - application of a further layer consisting of insulating material ( 5 ), whereby on the work surface ( 3 ) a base layer ( 6 ) with a first interconnect level ( 2c ) is generated, on this base layer ( 6 ) at least one further layer ( 6a ) for forming at least one bilayer ( 7 ) is applied, wherein a printed circuit board ( 1 ) with at least one second interconnect level ( 2 B ) is formed, and wherein a previously applied compound layer ( 8th ) with the underlying base layer ( 6 ) as well as with one on the connection layer ( 8th ) applied metal powder layer ( 4 ) to the bilayer ( 7 ) is merged. Method according to claim 1, characterized in that the position of the work surface ( 3 ) is changed after each merge process. A method according to claim 1 or 2, characterized in that the energy supply by means of a laser beam ( 9 ) he follows. Method according to claim 3, characterized in that the laser beam ( 9 ) using CAD data line by line over layers ( 10 ), which on the work surface ( 3 ) to be generated. Method according to one of claims 1 to 4, characterized in that as insulating material ( 5 ) powdered glass or powdered ceramic or a plastic granules is used. Method according to one of claims 1 to 5, characterized in that as connecting layer ( 8th ) powdered solder is used. Method according to one of claims 1 to 5, characterized in that as connecting layer ( 8th ) powdered hot melt adhesive is used. Method according to one of claims 1 to 7, characterized in that the metal powder layer ( 4 ) evenly thick on the work surface ( 3 ) and then to a solid base layer ( 6 ) is merged. Method according to one of claims 1 to 7, characterized in that the first, directly on the work surface ( 3 ) underlying base layer ( 6 ) is a metal foil. Method according to one of claims 1 to 7, characterized in that the first, directly on the work surface ( 3 ) underlying base layer ( 6 ) a non-conductive substrate ( 11 ). Method according to one of claims 1 to 10, characterized in that the position of the work surface ( 3 ) is lowered after each merge step down. Contraption ( 1a ) for producing a printed circuit board ( 1 ) with at least two tracks ( 2a . 2 B . 2c ) starting from a layer ( 4 ) of metal powder on a work surface ( 3 ), in particular with a method according to one of claims 1 to 11, wherein the device ( 1a ) a merger unit ( 12 ) for selective melting and a device ( 13 ) for removing unmelted metal powder and an application unit ( 14 ) for applying a further layer of a powdery insulating material ( 5 ), wherein on one on the work surface ( 3 ) applied base layer ( 6 ) multiple layers ( 10 ) with at least one second interconnect level ( 2 B ) are provided, and wherein in each case a layer by a fusion of a selectively on the base layer ( 6 ) applied compound layer ( 8th ) with a powdery layer applied thereto. Apparatus according to claim 12, characterized in that the fusion unit ( 12 ) a controllable laser device ( 16 ) having. Apparatus according to claim 13, characterized in that the fusion unit ( 12 ) has a data interface for CAD data, which the laser device ( 16 ) line by line over the top layer to be generated ( 18 ) Taxes. Device according to one of claims 12 to 14, characterized in that for the work surface ( 3 ) a vertically movable work table ( 17 ) is provided. Device according to one of claims 12 to 15, characterized in that as insulating material ( 5 ) powdered glass or powdered ceramic or a plastic granules is provided. Device according to one of claims 12 to 16, characterized in that a uniformly thick application of the first metal powder layer ( 4 ) on the work surface ( 3 ) and a merger with of the merger unit ( 12 ) is provided.