DE10340705B4 - Metal core circuit board and method of manufacturing such a metal core board - Google Patents

Abstract

Method for producing metal core circuit boards (1)
Printing by screen printing of a polymeric insulating layer (3) over the entire surface or at least provided with a recess (4), the insulating layer (3) applied over the entire area being subsequently structured to form a recess (4),
partial thermal curing of the insulating layer (3) at connection temperatures (TV) of 50 ° C to 100 ° C,
Whole-surface lamination by rolling a conductor layer (7) at temperatures (TW) of 100 ° C to 150 ° C, laminating pressures (pW) of 2 x 10 ⁵ Pa to 5 x 10 ⁵ Pa and laminating speeds (v) of 0.1 m / min to 10 m / min to form a defined continuous edge structure at the edges of the recess and
Structuring the applied conductor layer (7) exposing the recesses (4).

Description

The The invention relates to a method of manufacturing a metal core board, on a metal core board or on the use of a particular Material as an adhesive layer in carrying out such a method.

Out DE 41 18 397 A1 For example, there is known a metal core board equipped with semiconductor devices, which has a metal substrate as a printed circuit board core, an insulating adhesive layer on the metal substrate and a conductor layer on the insulating adhesive layer, the insulating adhesive layer firmly joining the metal substrate and the conductor layer. Through the conductor layer and the insulating adhesive layer leads an edged recess to the metal support. In the region of the recess, a semiconductor component is placed on the metal carrier in order to be able to dissipate heat generated in the semiconductor component via the metal carrier.

Generally the production of such a printed circuit board by applying is known an insulating adhesive layer on serving as a PCB core metal support and the subsequent one Placing a conductor layer whose underside also such wearing insulating adhesive layer, on the insulating adhesive layer, with the compound in use of heat he follows. Also known is the placement of the conductor layer on the Adhesive layer using a laminating method, wherein the metal support with the applied adhesive layer under the supply of a underside coated Metal foil is passed as a conductor layer between two rollers.

In the manufacture of such an arrangement is according to DE 41 18 397 A1 after completion of the multilayer printed circuit board, the insulating layer milled out in the region of the desired recess. Also generally known is the subsequent etching away of the layers above the metal support to form such a recess. Visible are such printed circuit boards in cross-section at sharp-edged contours of the recess, which extend substantially straight from the surface of the circuit board to the surface of the metal carrier and perpendicular to the surfaces.

As state of the art continue to be the DE 40 06 063 A1 , the DE 36 40 952 A1 and the DE 30 32 744 A1 called.

The DE 30 32 744 A1 discloses, as a special material for a film for coating a thermally highly conductive metal plate, a dispersion of metal oxide particles in an organic polymeric adhesive.

The DE 36 40 952 describes a substrate for applying switching structures on a flat design element, in particular an aluminum plate.

The DE 40 06 063 A1 discloses a method for producing a printed circuit board, wherein a part of a metal layer combined with a substrate layer is exposed by means of a laser and a mask.

The The object of the invention is a method for manufacturing a printed circuit board with a metal carrier as the PCB core as well to provide a metal core board, in which recesses have an improved contour in the metal core board.

These The object is achieved by a method for producing a metal core circuit board with the features of patent claim 1 and a metal core board solved with the features of claim 7.

advantageous Embodiments are the subject of dependent claims.

According to the method, for producing a metal core board from the steps of applying a polymeric insulating layer on serving as a printed circuit board core metal carrier and the subsequent placement of a conductor layer on the polymeric insulating layer is assumed, wherein the compound using heat, which is supplied accordingly takes place. The application of the polymeric insulating layer is carried out in accordance with the preferred embodiment prior to placement of the conductor layer to form at least one recess in the insulating layer, so that the insulating layer is applied structured on the metal support. Also possible is the structuring after the application of the insulating layer. In addition, the process sequence, ie the application of the insulating layer and the placement of the conductor layer under temporal and thermal parameters, wherein an edge region of the insulating layer extends to the recess, ie forms a transition with respect to the contour transition. The region of the insulating layer between the edge region of the applied conductor layer towards the recess and the transition region of the insulating layer to the metal carrier is to be understood as the region of the edge of the insulating layer relative to the recess. When using resin as an insulating layer, a preferred bonding temperature of the insulating layer material of about 50 ° C-100 ° C, preferably from 70 ° C-75 ° C, has proven to be particularly advantageous. When using a copper foil as the conductor layer temperature has a temperature for laminating rollers in a suitably selected temperature range of 100 ° C-150 ° C, preferably 130 ° C-140 ° C, ins special about 135 ° C, proved to be particularly advantageous. The conductor layer is deposited according to first experiments preferably under a suitably selected laminating pressure of about 2 × 10 ⁵ Pa-5 × 10 ⁵ Pa, preferably about 4 × 10 ⁵ Pa. The lamination speed when placing the conductor layer, for example, during lamination and performing between two laminating rollers starting from one side of the circuit board edge or insulating layer to the opposite side, is selected slowly and is preferably about 2-10 m / min. According to first experiments, particularly preferred about 0.5 m / min.

Device arises according to Thus, a metal core board, which a metal support as Printed circuit board core, a polymeric insulating layer on the metal substrate, a Conductor layer on the insulating layer, wherein the insulating layer of the metal support and the conductor layer firmly interconnects, and a recess has through the conductor layer and the insulating layer to the metal support. Due to the process, the metal core board is designed in this way that the insulating layer from the region of an edge of the conductor layer to the recess on the one hand and on the other hand from the transition region between the insulating layer and the metal carrier a flowing one Contour contour has. For the application of the method offers itself as an insulating layer in particular Resin, preferably resin with ceramic components.

When metal support is preferably a carrier material made of copper or aluminum, which with a view to the heat dissipation of a semiconductor component used in the recess particularly is well suited.

When Conductor layer is preferably a printed circuit board or conductor foil used as the material for copper is preferred. In front the placement of the conductor layer on the insulating layer, it is for increase the adhesion particularly advantageous if of the conductor layer whose Side, which faces after putting the insulating layer, is rough or roughened. The roughening can according to particularly preferred Procedure be carried out by mechanical or chemical means.

The polymeric insulating layer is advantageously by means of a screen printing process structured applied, wherein according to first attempts a very slow squeegee speed of 0.2-0.7 m / min, preferably from about 0.5 m / min has proved to be particularly advantageous. However, they are also squeegee speeds outside These particularly preferred speed values can be used.

Especially advantageous proves according to the first Try the targeted temporal and thermal processing of the layer after its application to the metal support and before placing the Conductor layer in a way that the insulating layer in front already partially cured when the conductor layer is placed on, wherein curing so far done that the conductor layer still adheres when placed. Corresponding the insulating layer is not fully cured as it is taken alone would be known. Particularly advantageous is a so-called hand-dry curing proved to be suitable.

The Conductor layer is preferably by lamination on the insulating layer placed on, wherein the conductor layer when placed on a suitable temperature is brought. Heating can be done by heating up accordingly of pinch rollers and the like. Be made indirectly, which is the metal core board Press on the insulating layer. A metal core board with a corresponding recess can be advantageous for placing a Circuit element, z. B. semiconductor device, can be used because the heat of the circuit element via the metal carrier well drained can be.

Next the above-mentioned as already particularly preferred parameter ranges in terms of temperatures, pressures and speeds is an application with parameter values outside these areas, especially when using other than the previous one tested materials, in the field of feasible.

One embodiment will be explained in more detail with reference to the drawing. Show it:

1 a partial sectional view through a metal core board during its manufacture at the beginning of a lamination process for placing a conductor layer on an insulating layer;

2 a section through the metal core board after the lamination process; and

3 a section through the finished with a recess metal core circuit board, wherein in the recess, a semiconductor device is used.

Like this 1 is apparent, is an intermediate step of manufacturing a metal core board 1 represented, wherein the metal core by a metal carrier 2 is formed, which serves as a circuit board core. According to preferred embodiments, the metal support is made of copper or aluminum. Other suitable materials are usable.

In a first process step is applied to the metal support 2 a polymeric insulating layer 3 on brought and thereby or possibly structured below. The application of the insulating layer 3 is preferably carried out by means of a screen printing process, wherein a structuring is carried out. According to the first experiments, a slow doctoring speed of preferably approximately 0.5 m / min has proved to be advantageous for the screen printing process.

In the structured application of the polymeric insulating layer, one or more recesses 4 as needed in the insulating layer 3 educated. In the area of the recess shown 4 thus remains the surface of the metal support 2 free of the material of the insulating layer 3 , The edge area between the material of the insulating layer 3 and the recess 4 is thereby replaced by a transition region from an upper point or edge 5a to which the insulating layer 3 continuously running, and by a lower point or edge 5b defining the transition point of the material of the insulating layer 3 to the metal carrier 2 forms, from which the isolierschichtfreie recess 4 starts. In known embodiments, this transition region 5a . 5b by a relative to the surfaces of the insulating layer 3 and the metal carrier 2 vertical or nearly vertical wall with angular transitions in the area of the two transition points 5a . 5b educated. Depending on the configuration of the structured screen-printing process, the insulating layer is applied during the application step 3 already a rounding off of the material flow in the area of the transition points 5a . 5b made, so that a relative to the vertical wall flowing, ie, in particular edge-free contour profile is formed.

If the material of the applied polymeric insulating layer 3 is still too cold and / or too little cured, it is subjected to a drying or curing process. For curing, the arrangement of the metal support 2 with the insulating layer 3 preferably in the region of a heating device 6 led, which is the material of the insulating layer 3 heating up. Before putting on a conductor layer 7 becomes the insulating layer 3 so far, ie only partially cured, that the conductor layer 7 when putting on the insulating layer 3 can stick. The insulating layer 3 is thus not fully cured but preferably cured to a so-called hand-dry state. It is by means of the heater 6 brought to a suitable bonding temperature TV, which is preferably according to first experiments in a temperature range of 70 ° C-100 ° C, more preferably 70 ° C-75 ° C.

The conductor layer 7 is preferably provided as a printed circuit board or conductor foil made of copper or similar suitable material. Before putting on the conductor layer 7 on the polymeric insulating layer 3 becomes the side of the conductor layer 7 , which is the insulating layer 3 when facing or touchdown, roughened, if it is not already suitable rough. Roughening can be done chemically or mechanically in a manner known per se.

In the preferred embodiment, the placement of the conductor layer takes place 7 by supplying the conductor layer 7 from a roll of film 8th to a laminating device, of which in 1 only two laminating rollers 9 are shown. The copper layer 7 is doing with the help of the laminating rollers 9 with a laminating pressure pW on the insulating layer 3 pressed. Initial tests with a laminating pressure pW of about 2-5 bar, preferably about 4 bar, showed advantageous results. Carrying out the arrangement of metal carrier 2 , Insulating layer 3 and the conductor layer to be applied thereon 7 through the laminating rollers 9 was carried out in first experiments at a rate of 0.1-10 m / min, with a value of 0.5 m / min proved to be particularly advantageous. For setting or lamination, the conductor layer 7 heated, preferably by heating the laminating rollers 9 to a temperature TW. The temperature TW of the laminating rollers used in the first experiments 9 had values in the range of 100 ° C-150 ° C, with temperature values TW in the range of 135 ° C proved to be particularly advantageous.

The process of applying the insulating layer 3 on the metal carrier 2 as well as the placement of the conductor layer 7 on the insulating layer 3 , which was previously structured, thus takes place using thermal energy. According to preferred embodiments, heating takes place on the one hand by a heating device 6 for partial curing of the on the metal support 2 applied insulating layer 3 and on the other hand by heating the conductor layer to be applied 7 during the lamination process. To emphasize is the structuring of the insulating layer 3 before placing the conductor layer 7 forming at least one recess 4 in the insulating layer 3 The structuring is advantageously already carried out during the screen printing process.

Furthermore, the process sequence is carried out under a variety of temporal and thermal parameters such that the transition or edge region 5a . 5b the polymeric insulating layer 3 to the insulating layer-free region of the recess 4 out with a flowing course contour runs or is formed. It has already been described to form a running transition of the transition region 5a . 5b in the structured application of the insulating layer 3 on the metal carrier 2 , Additionally or alternatively, a bleeding of the transition region takes place 5a . 5b the insulating layer 3 when placing the conductor layer 7 on the insulating layer 3 instead of. By placing under the appropriate laminating pressure pW and at the appropriate temperature TW, the material of the insulating layer passes 3 in the transition area 5a . 5b like this 2 is apparent. Additionally or alternatively, the bleeding of the material of the insulating layer in the transition region 5a . 5b also by the subsequent or final pre-drying and final curing at preferably 150 ° C for one hour after lamination.

How out 3 can be seen, in subsequent processing steps a wider recess in the patch conductor layer 7 above the recess 4 the polymeric insulating layer 3 trained and in the recess 4 a semiconductor device 10 used as a circuit element. The semiconductor device 10 is doing with his body directly on the metal support 2 attached so that in the semiconductor device 10 generated heat over the metal carrier 2 is dissipated. In a manner known per se, the semiconductor component becomes 10 with, for example, bonding wires 11 with corresponding areas of the conductor layer 7 , which is structured accordingly, electrically conductively connected. As can be seen from the sectional view, the process described describes a metal core circuit board 1 formed, which in the area of recesses 4 passing through the polymeric insulating layer 3 to the metal carrier 2 lead through, a flowing and / or oblique contour in the transition area 5a . 5b the insulating layer 3 exhibit.

When Material for the adhesive layer is preferably used resin, in particular resin with ceramic components, to perform the described method or a circuit board to manufacture in such a way.

1

Metal core printed circuit board

2

metal support

3

polymeric insulating

4

Recess in 3

5a, 5b

Transition area of 3 to 4

6

heater

TV

Connection temperature of 3

7

Conductor layer / conductor foil

8th

film roll

9

Laminator / laminating

TW

temperature

pw

lamination

v

laminating

10

Semiconductor component

11

Bond wires

Claims (7)

Method for producing metal core circuit boards ( 1 ) by printing by screen printing a full-area or at least. With a recess ( 4 ) provided polymeric insulating layer ( 3 ) on a metal support ( 2 ), wherein the full-surface applied insulating layer ( 3 ) subsequently with the formation of a recess ( 4 ), thermal partial hardening of the insulating layer ( 3 ) at connection temperatures (TV) of 50 ° C to 100 ° C, laminating all over by rolling a conductor layer ( 7 ) at temperatures (TW) of 100 ° C to 150 ° C, laminating pressures (pW) of 2 x 10 ⁵ Pa to 5 x 10 ⁵ Pa and laminating speeds (v) of 0.1 m / min to 10 m / min with formation a defined continuous edge structure at the edges of the recess and structuring the applied conductor layer ( 7 ) exposing the recesses ( 4 ). Process according to claim 1, in which as metal carrier ( 2 ) a support material of copper or aluminum is used. A method according to claim 1 or 2, wherein as a polymeric insulating layer ( 3 ) Resin with ceramic components is used. Method according to one of Claims 1 to 3, in which, as the material of the conductor layer ( 7 ) Copper is used. Method according to one of claims 1 to 4, wherein the conductor layer ( 7 ) on the polymeric insulating layer ( 3 ) facing side is rough or roughened. Method according to one of claims 1 to 5, wherein the polymeric insulating layer ( 3 ) is structured by means of a screen printing process, in particular with a doctor speed of 0.2-0.7 m / min, preferably about 0.5 m / min applied. Metal core board ( 1 ) produced by a method according to at least one of claims 1-6, characterized in that the recess ( 4 ) in a transitional area ( 5a . 5b ) of insulating layer ( 3 ) and metal supports ( 2 ) has a continuous edge structure.