Method of manufacturing a printed circuit board

Abstract

A method of manufacturing a printed circuit board or a sub-assembly thereof by coupling at least two elements of insulating materials with different properties on adjacent side surfaces and covering the elements with a layer of conductive material and building up at least one further layer at least partly overlapping the at least two elements.

Claims

1. A method of manufacturing a printed circuit board or a sub-assembly thereof comprising the following steps: providing at least two elements of insulating material, coupling or connecting the elements of insulating material on at least one adjacent side surface, covering the elements of insulating material with a layer of conductive material on at least one surface in such a way that the layer of conductive material is placed in direct contact with the elements of insulating material, and building up at least one further layer of the printed circuit board at least partly on the elements of insulating material, wherein the elements of insulating material are made of insulating material having different mechanical, chemical or physical properties and wherein the at least one further layer of the printed circuit board is at least partly overlapping different elements of insulating material.

2. The method according to claim 1, wherein the layer of conductive material is structured after having been connected with the elements of insulating material.

3. The method according to claim 1, wherein the elements of insulating material are covered with a layer of conductive material on both surfaces.

4. The method according to claim 1, wherein at least one of the elements of insulating material is provided with at least one cut-out portion for inserting another element of insulating material.

5. The method according to claim 1, wherein the elements of insulating material are provided with protrusions and corresponding recesses on adjacent side surfaces for mutual coupling or connection.

6. The method according to claim 1, wherein at least one of the elements of insulating material to be connected or coupled is made of flexible material to be coupled or connected with an element made of rigid insulating material.

7. The method according to claim 1, wherein the elements of insulating material are connected by gluing or similar connecting techniques.

8. The method according to claim 1, wherein when using flexible elements of insulating material a further layer of the printed circuit board is removed at least partially according to a flexible element of the insulating material and/or is aligned with at least one flexible element of insulating material.

Description

SHORT DESCRIPTION OF THE DRAWINGS

(1) In the following the invention will be explained in more detail by way of exemplary embodiments schematically illustrated in the accompanying drawing. Therein:

(2) FIGS. 1 to 1g depict different steps of a method according to the invention for manufacturing a printed circuit board or a sub-assembly thereof according to the invention;

(3) FIG. 2 depicts a schematic plan view according to arrow II of FIG. 1c indicating the relative position between different parts or elements of insulating material; and

(4) FIG. 3 is a schematic plan view similar to FIG. 2 showing the connection between different parts or elements of insulating material being provided with coupling elements according to a further embodiment of the inventive printed circuit board.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(5) In a first, method, step according to FIG. 1a a first insulating layer 1 of insulating material, for example an insulating prepreg, in particular FR4, is provided.

(6) According to FIG. 1b in a further method step an area 2 is removed from the first insulating material 1.

(7) Into this cut-out area 2 another insulating material 3 is inserted according to FIG. 1c.

(8) Thereafter on at least one surface, and in particular on both surfaces, as can be taken from the method step being shown in FIG. 1d, layers 4 of conductive material are provided on both surfaces of the first, insulating material 1 as well as the second insulating material 3 having been inserted into the removed or out-out area 2.

(9) According to the method, step being shown in FIG. 1d there is provided a core substrate comprising different insulating materials 1 and 3 and layers 4 of conductive material allowing a further build up of further layers of a printed circuit board or sub-assembly thereof to be provided, as can be taken from the following figures. In FIG. 1e it is furthermore shown that the layers 4 of conductive material, having been provided according to FIG. 1d, are structured for providing a conductive structure or pattern on both surfaces or sides of the core substrate comprising different parts or elements 1 and 3.

(10) Thereafter according to FIG. 1f further layers of a multilayer printed circuit board being designated as 5, 6, 7 and 8 are provided. From FIG. 1f it can be clearly taken that these further layers are overlapping both elements 1 and 3 of the core substrate as well as the structured layers 4 allowing the usage of known production methods or steps for producing printed circuit boards.

(11) In particular the method steps being shown in FIGS. 1e and 1f for structuring any conductive layers, being designated with 6 and 8 in FIG. 1f as well a further build up of multiple layers of the printed circuit board 10 can be repeated several times according to the respective requirements, being schematically indicated with, the vertical line of points in FIG. 1.

(12) After completion of the build up of the printed circuit board being indicated, generally with 10 in FIG. 1g any part(s) of the multilayer structure of the circuit board 10 overlapping the second, element or part 3 of the core substrate may be removed, being indicated with 11 in FIG. 1g, in particular in case of producing a rigid-flexible printed circuit board 10 when using a rigid material as first insulating material 1 and a flexible material as second insulating material 3.

(13) Thereby the flexible part of the rigid-flex printed circuit board 10 being provided according to FIG. 1g can be provided on the basis of the position of the flexible insulating material 3 of the rigid-flex core substrate. From FIG. 1g it can be taken that any further layers building up the multilayer, in particular rigid-flex printed circuit board 10 are partly overlapping the region of contact between the parts or elements 1 with the element 3 providing a better connection of the different parts 1 and 3 and avoiding excessive strains or mechanical stresses, in particular in the region of the connection between the parts or elements 1 and 3.

(14) In FIG. 2 there is schematically shown that the part or element 3 of the second insulating material is inserted into a respective cut-out area 2 of the surrounding element or part 1 of the first insulating material.

(15) From the schematic drawing of FIG. 3 it can be taken that different insulating materials 21 and 22 are connected on at least one adjacent side surface 23 and 24. For assisting the coupling or connection of the insulating materials 21 and 22 the insulating material 21 is provided with a protrusion 25 fitting into a corresponding recess 26 of the second insulating material 22.

(16) After connecting the elements 21 and 22 of different insulating material comprising different mechanical, physical or chemical properties as being indicated in FIG. 3 a further build-up of the layers of a printed circuit board will take place, for example according to the further method steps being shown in FIG. 1d to FIG. 1g.

(17) If necessary, a respective number of protrusions 25 as well as corresponding recesses 26 may be provided on the side surfaces 23 and 24.

(18) Furthermore such corresponding protrusions and recesses 25 and 26 may also be provided when inserting an insulating material into a cut-out area of another surrounding or larger insulating material, as can be taken from FIGS. 1 and 2.

(19) According to the necessary requirement the insulating materials 1 and 3 or 21 and 22 have different mechanical, chemical or physical properties, such as is for example indicated in FIG. 1 comprising a rigid insulating material 1 as well as a flexible insulating material 3.

(20) Being based on the different insulating materials being used there may be provided a flexible, rigid, rigid-flexible or semi-flexible printed circuit board or a sub-assembly thereof.