Patent Application
20230397332
The present invention relates to a method for producing a circuit board and to a shaped part for use in this method.
In the production of circuit boards, especially for high-current applications, current-carrying components are embedded in insulating material as conductors or conductor elements and connected to conductor structures for connecting electronic components to the circuit board. Corresponding circuit boards and production methods are known from EP 1 842 402 and DE 10 2011 102 484.
In the known production methods, the conductors or conductor elements are positioned on a copper foil and welded to it, then pressed with insulating material before a conductor structure with strip conductors and connection points is worked out of the copper foil.
Based on the above-mentioned prior art, the problem underlying the present invention is to simplify the production of circuit boards, in particular with a plurality of segments, to save insulating material and thereby also to reduce the height of the circuit board, among other things, in order to make heat management on circuit boards significantly more efficient.
The problem of the invention is solved by a new method and a new shaped part.
The method for producing circuit boards according to the invention comprising the following steps:
In order to form the segments and, if necessary, different circuit board sections, slot-shaped perforations are introduced into the shaped part along a perforation line, for example. The segments correspond, for example, to the conductors according to patent application EP 1 842 402 and/or the shaped parts according to patent application DE 10 2011 102 484, the contents of which are included by reference herein. Basically, little material is intended to be removed during formation of the segments, since with increasing segmentation, the required processing time possibly also increases. The segmentation of the shaped part is intended to create a joint which is preferably completely filled with insulating material in the final state of the circuit board. However, it has proved advantageous to separate the individual segments from one another only after the conductor structure has been attached, because this considerably simplifies the positioning of the conductor structure in relation to the segments. The joint between the segments should be at least as wide as to prevent electrical breakdown through the joint by the insulating material to be applied. In this context, a minimum width of approx. 200 μm has proved to be preferred. However, the joint should not be too wide either, because the removed material has to be filled with insulating material when the shaped part is embedded in insulating material. Since insulating material is preferably applied laminarly, e.g. as an insulating mat (pre-preg=resin-impregnated fiber mat), there is a lack of corresponding insulating material at the joint. With a correspondingly small joint, the material deficit can be easily compensated. In the case of a larger joint, groove-like depressions could possibly form along the joint on the surface of the circuit board and lead to delamination, which is to be avoided as far as possible. A maximum width of the perforation line or joint of approx. 2000 μm seems reasonable. The intermediate product after embedding the shaped part in insulating material is referred to in the scope of the present invention as a circuit-board substrate. A conductor structure for connecting electronic components is then attached to this circuit-board substrate. For this purpose, the circuit-board substrate is coated with a copper foil, for example, from which strip conductors and connection points are subsequently worked out, e.g. using an etching process. However, prefabricated conductors and pads can also be attached to the circuit-board substrate as a conductor structure. According to the invention, the integral connection of the segments is released after attachment of the conductor structure by cutting through the webs of material. This allows the conductor structure to be positioned particularly accurately in relation to the embedded segments. By embedding in the insulating material, the positions of the segments relative to each other are fixed and remain aligned even after cutting through the webs of material. The phrase “webs of material” in the plural is also intended to include a single web of material in the singular.
As a result, the invention also favors minimization of the amount of insulating material used in the production of the circuit board, which yields several advantages at once: On the one hand, material costs are saved and, on the other hand, the thickness or overall height of the circuit board is reduced. The less insulating material used, the thinner the circuit board. The thinner the joint, the less insulating material (or resin) is required to fill the joint. In addition, the insulating material is not only electrically insulating, but also heat insulating, so that reducing the amount of insulating material also favors the heat management of the circuit board.
It is within the scope of the invention that steps A to D are preferably, but not mandatorily, carried out in the sequence indicated. As indicated below, the steps and sub-steps of the method can also be carried out, at least partially, in a modified order.
Preferred further embodiments of the invention are the subject matter of the dependent claims.
It may be reasonable if step A comprises at least one of the following sub-steps, wherein the substeps are preferably, but not mandatorily, carried out in the indicated order
It may be useful if step B comprises at least one of the following sub-steps, wherein the sub-steps are preferably, but not mandatorily, carried out in the indicated order:
It may prove expedient if step C comprises at least one of the following sub-steps, wherein the sub-steps are preferably, but not mandatorily, carried out in the indicated order
It may be advantageous if step D comprises at least one of the following sub-steps, wherein the sub-steps are preferably, but not mandatorily, carried out in the indicated order
According to this method, a circuit board consisting of several planes can also be produced. Two or more shaped parts can also be present in such a circuit board, or two or more circuit boards can be connected by a shaped part to form a, in particular, three-dimensional circuit board arrangement. The shaped parts can be arranged parallel to each other. The conductor structure can also extend over several planes.
Another aspect of the present invention relates to a shaped part for producing a circuit board, preferably according to the method according to one of the preceding embodiments, comprising two segments which are integrally connected only via isolated webs of material. This shaped part can be prefabricated as a mass-produced component and provided for the production of a plurality of circuit boards in series production.
It can be useful if the shaped part has slot-shaped perforations along a perforation line, which are interrupted by the webs of material.
Another aspect of the present invention relates to a circuit board arrangement comprising at least two circuit boards and at least one shaped part according to one of the two preceding embodiments, wherein each segment of the shaped part is connected to the at least two circuit boards and the segments of the shaped part are electrically insulated from each other by cutting through the webs of material. This allows articulated or angled as well as electrically conducting connections between the circuit boards to be created by the segments in a particularly simple manner.
Further preferred embodiments of the invention result from any combination of the features disclosed in the description, claims and drawings.
In the context of the present invention, the term “shaped part” is preferably understood to mean a laminar, plate-shaped component, in particular made of an electrically conducting solid material such as metal, in particular copper. The shaped part preferably has no irregularities or interruptions within its contour.
During perforating, slots or holes are made in the shaped part along the perforation line where the segments can be easily cut off.
The term “conductor structure” is understood to mean anything capable of effecting an electrically conducting connection to at least one of the segments through the insulating material. The conductor structure preferably has at least one of the following elements: strip conductor, connection point, pad, conductor, contact, via, through-contact. The conductor structure is preferably an arrangement comprising several of these elements, possibly several different ones of these elements.
In the context of the present invention, an electronic component is understood to be, for example, a current-generating or current-consuming component, such as a processor, memory, transistor, resistor, generator, a diode, in particular an LED; or a component associated therewith, such as for example an optical component, for example a lens; but also a connection component, such as for example a plug, terminal or the like.
Unless otherwise indicated, formulations in the plural are used in the context of the invention for practical reasons in order to avoid linguistically more complex differentiations according to singular and plural. It is within the scope of the invention that formulations in the plural (e.g. “webs of material”) include both the singular (“one web of material”) and the plural (“several webs of material”).
The preferred embodiments of the invention are described in detail below with reference to the accompanying drawings.
In the first embodiment of the invention, which is described below with reference to
In step A of the method according to the invention, the shaped part 1 is provided for subsequent processing. In this process, two segments 2a, 2b of a circuit board section 2 are formed by introducing corresponding perforation lines P into the shaped part 1. In the present embodiment, the circuit board section 2 is formed within a self-contained, polygonal perforation line P with eight corners. During perforating, long, slot-shaped openings with a preferably constant width in the range from approx. 200 to 2000 μm are introduced into the shaped part 1 along the perforation line P by appropriate material removal, so that the segments 2a, 2b remain integrally connected only by means of isolated webs of material M. The entire circuit board section 2 is connected via the self-contained perforation line P to the surrounding edge region of the shaped part 1, in which a reference mark R is located. The reference mark R is used to determine the position on the surface of the shaped part 1 and is, for example, an opening with which the shaped part 1 is placed on a pin. Several reference marks R can be provided on the shaped part 1.
After forming the segments 2a, 2b, the shaped part 1 is embedded at least in sections in insulating material 3 in step B of the method according to the invention. The resulting intermediate product is referred to as circuit-board substrate LS. Two resin-impregnated fiber mats (pre-preg) 3, ideally of a shape and size matched to the shaped part 1, are applied to the upper and lower sides of the shaped part 1. These resin-impregnated fiber mats 3 are pressed together with the shaped part 1 in such a way that the flowable resin penetrates into the perforations along the perforation line P and completely permeates the spaces between the webs of material M. In this step, also the electrically conducting surface element 4, from which the conductor structure is worked out in step C, can simultaneously be connected to the insulating material by pressing. In this process, for example, a sandwich-like layer composite, as shown in
In step C of the method according to the invention, the conductor structure 4a, 4b is attached to the circuit-board substrate LS. This step comprises as a sub-step applying at least one copper foil 4 as an electrically conducting surface element to the circuit-board substrate LS, for example one copper foil 4 each on both the upper side and the lower side of the circuit-board substrate LS. This is preferably already done in step B, so that the copper foils 4 are pressed together with the shaped part 1 and the insulating material 3 arranged in each case between the copper foil 4 and the shaped part 1 to form a layer or material composite. In step D, a conductor structure with strip conductors 4a and connection points 4b is then formed from this copper foil 4, e.g. using an etching process. At the connection points 4b, the strip conductors 4a are connected to the segments 2a, 2b via contacts 5 (e.g. vias or laser vias (left) or through-contacts (right)).
After forming the conductor structure 4a, 4b on the circuit-board substrate LS, the webs of material M, which integrally connect the segments 2a, 2b, are cut through by material removal. This is accomplished, for example, with a drill that is guided to the corresponding positions of the webs of material M by means of the reference mark R. When cutting through the webs of material M, preferably all the material of the webs of material M is removed over the entire length corresponding to the width of the former perforation line P, which now forms a joint. If necessary, the separation point is filled with insulating material 3 so that the risk of electrical breakdown between the segments 2a, 2b—especially at the points of the former webs of material M—is minimized. Whether or not the separation point is filled with insulating material 3 can be determined primarily as a function of the dielectric strength of the circuit board or the insulating material.
Subsequently, the finished circuit board LP is separated from the surrounding region along the self-contained perforation line P, which surrounds the circuit board section 2 and the segments 2a, 2b.
The second embodiment of the present invention, which is described below with reference to
In the second embodiment, the shaped part 1, which is configured as a rectangular copper plate, comprises a total of four largely identical circuit board sections 2, which are arranged in matrix form in two columns and two rows distributed over the surface of the shaped part 1.
An octagonal, self-contained perforation line P surrounds each of the four circuit board sections 2. Each circuit board section 2 within the circumferential perforation line P is integrally connected to a surrounding edge region of the shaped part 1, on which various reference markings R are located, by means of the isolated webs of material M. Within each circuit board section 2, a plurality of segments 2a-i are formed by further perforation lines P. For illustration purposes, the subsequent conductor structure 4a, 4b with connection points 4b and strip conductors 4a extending between them is drawn by dash lines in each circuit board section 2. It can be seen here that the conductor structure 4a, 4b does not cover the webs of material M when projected onto the extension plane of the shaped part 1. Consequently, the webs of material M are accessible for later processing.
Preferably, the segments 2a-i and perforation lines P completely fill the respective circuit board section 2 surface-wise, as shown in the two circuit board sections 2 in the left half of
Deviating from the two circuit board sections 2 in the left half of
As in the first embodiment, this shaped part 1 (still without the conductor structure drawn in for illustration purposes only) is embedded in insulating material 3 and then provided with a corresponding conductor structure 4a, 4b at the positions shown in
The number and shapes of PCB sections 2 and segments 2a-i as well as reference marks R can be changed as desired.
The third embodiment of the present invention, which is described below with reference to
Here, the shaped part 1 is used to produce three-dimensional circuit board structures and, in particular, to form articulated or angled connections between two or more circuit boards LP. Deviating from the preceding embodiments, each segment 2a, 2b, 2c is connected to two circuit-board substrates LS or circuit boards LP, so that the respective segment 2a, 2b, 2c forms an articulated or angled connection between two or more circuit boards LP or circuit-board substrates LS.
The shaped part here is an approximately conductor-shaped element which is worked out of a planar, rectangular copper plate (
In step B, the shaped part 1 is embedded in insulating material 3 to form circuit-board substrates LS. In this process, each segment 2a, 2b extends over almost half of its length in a first circuit-board substrate LS and over almost half of its length in a second circuit-board substrate LS.
In step C, conductor structures are created on one or more of these circuit-board substrates LS to form the circuit board LP. For this purpose, the shaped part 1 is connected to an electrically conducting surface element such as a copper foil, or via connecting means sections, as known from DE 10 2018 203 715. Subsequently, the strip conductors 4a as well as the connection points 4b for contacting the segments 2a, 2b, 2c are worked out of this electrically conducting surface element, e.g. by etching.
In step D, the web of material M is cut through so that the integral connections between the parallel segments 2a, 2b, 2c are released.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 125 140.8 | Sep 2020 | DE | national |
This application is a U.S. National Phase application under 35 U.S.C. 371 of International Application No. PCT/EP2021/075095, filed on Sep. 13, 2021, which claims priority to German Patent Application No. 10 2020 125 140.8, filed on Sep. 25, 2020. The entire disclosures of the above applications are expressly incorporated by reference herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/075095 | 9/13/2021 | WO |
