DE102020102423A1 - Component carrier with a small overhang and with a through hole with different sizes of the front and rear windows - Google Patents

Abstract

A component carrier (100) which has an electrically insulating layer structure (102) with a front side (104) and a rear side (106), a first electrically conductive layer structure (108) which covers the front side (104) of the electrically insulating layer structure (102) , a second electrically conductive layer structure (110) covering the rear side (106) of the electrically insulating layer structure (102), and a through hole (112) which extends through a first window (114) of the first electrically conductive layer structure (108) , the electrically insulating layer structure (102) and a second window (116) of the second electrically conductive layer structure (110), the second window (116) having a width (118) that is smaller than another width (120) of the first Window (114), and an overhang (122) of at least one of the first electrically conductive layer structure (108) and the second electrically conductive layer structure (110) over at least at least one side wall (124) of the electrically insulating layer structure (102), which delimits the through hole (112), is not more than 10 μm.

Description

The invention relates to a component carrier and a method for producing a component carrier.

In connection with the increasing product functionalities of component carriers, which are equipped with one or more electronic components, and increasing miniaturization of these components as well as an increasing number of components to be mounted on the component carriers, e.g. Printed circuit boards, ever more powerful array-like components or housings with several components are used, which have a large number of contacts or connections with an increasingly smaller distance between these contacts. The removal of heat generated by such components and the component carrier itself during operation is becoming an increasing issue. At the same time, the component carriers must be mechanically robust and electrically reliable in order to be able to be operated even under harsh conditions. All of these requirements go hand in hand with a further miniaturization of component carriers and their components.

In addition, it can be advantageous to contact electrically conductive layer structures and / or components which are embedded in a component carrier efficiently and in a suitable quality. The formation of mechanical vias and laser vias, which may be filled with copper, can be advantageous for these and other purposes.

There may be a need to manufacture a component carrier with suitable electrical reliability.

According to an exemplary embodiment of the invention, a component carrier is provided which has the following: an electrically insulating layer structure with a front and a rear side, a first electrically conductive layer structure which covers the front side of the electrically insulating layer structure, a second electrically conductive layer structure which Back of the electrically insulating layer structure covered, and a through hole (in particular a laser through hole), which extends through a first window of the first electrically conductive layer structure, the electrically insulating layer structure and a second window of the second electrically conductive layer structure, wherein the second window Has width that is smaller than another width of the first window, and wherein an overhang of at least one of the first electrically conductive layer structure and the second electrically conductive layer structure over at least s a side wall of the electrically insulating layer structure that delimits the through hole is not more than 10 μm.

According to a further exemplary embodiment of the invention, a method of producing a component carrier is provided, the method comprising the following: providing an electrically insulating layer structure with a front side and a rear side, the front side having a first electrically conductive layer structure and the rear side having a second electrically conductive layer structure is covered, performing a first laser drilling through the first electrically conductive layer structure and into the electrically insulating layer structure from the front to thereby form a blind hole in the electrically insulating layer structure, and then performing a second laser drilling through the second electrically conductive layer structure and through the electrically insulating layer structure from the rear, thereby expanding the blind hole into a through hole, the first laser drilling being carried out with a laser beam which is a has a greater width than another width of another laser beam which is used for the second laser drilling.

In connection with the present application, the term “component carrier” (or “component carrier”) can in particular refer to any support structure that is capable of receiving one or more components (or components) thereon and / or therein in order to provide mechanical support and / or or to ensure electrical connectivity. In other words, a component carrier can be configured as a mechanical and / or electronic carrier for components. In particular, a component carrier can be a (printed) printed circuit board, an organic intermediate carrier (interposer) and an IC (integrated circuit) substrate. A component carrier can also be a hybrid plate which combines various of the types of component carriers mentioned above.

In connection with the present application, the term “layer structure” can in particular denote a continuous layer, a structured layer or a multiplicity of non-continuous islands within a common plane.

In connection with the present application, the term “window” can in particular designate a through hole, in particular a circular through hole, which extends through an electrically conductive layer structure as a result of a treatment of this electrically conductive layer structure. Expressed vividly, the energy of the laser beam can be electrical Remove the conductive layer structure in the area of the window.

In connection with the present application, the term “through hole” can in particular refer to a hole that extends completely through the entire layer structures and that can be formed in particular and preferably by laser processing. Thus, the through hole can be a laser through hole. Such a through-hole can have, for example, two opposite, tapering sections which extend from the two opposite main surfaces of the electrically insulating layer structure. A through hole can be, for example, by a combination of laser shots from the front and the back, i.e. from the two opposite main surfaces of the layer structures. One or more laser shots can be carried out from each of these sides. It may also be possible to form a through hole by laser machining from only one main surface. In addition, a through hole may also be formed by methods other than laser processing, e.g. through a plasma treatment.

In connection with the present application, the term “width” of a window and a first or second laser beam can in particular mean a diameter (in particular a maximum diameter) of the preferably circular window and a diameter (in particular a maximum diameter) of the preferably circular first or second Laser beam, respectively, denote.

In the context of the present application, the term “overhang” can in particular denote a partial length of a respective one of the electrically conductive layer structures that directly adjoin the respective window, over which partial length the electrically conductive layer structure extends laterally beyond the electrically insulating layer structure (or in cantilevered). It can happen that the overhanging material of the respective electrically conductive layer structure is not locally supported by material of the electrically insulating layer structure along the extension (or extension) of the overhang, due to the presence of a part of the through hole in a pocket below the overhanging electrically conductive Layer structure. With regard to the above statement that overhanging material cannot be supported locally, it should be said that the overhang can refer to the essentially resin-free area under the respective electrically conductive layer structure. However, one skilled in the art will understand that some residue of resin may be present even within an overhang gap. To quantify or measure the value (or size) of the overhang, the length of the substantially resin-free (where resin may refer to the electrically insulating layer structure) undercut (or undercut) can be measured directly under an overhanging electrically conductive layer structure (especially if it is not the most receding point or the entire relief under the overhanging electrically conductive layer structure, eg copper layer). In other words, the undercut can be measured directly under the electrically conductive layer structure in order to measure the overhang.

In connection with the present application, the term “offset from the front with respect to the rear” (“front-side-to-back-side offset”) can in particular refer to a lateral displacement between the centers of the laser beams when drilling from the front and from the rear . Consequently, the “offset” can also mean a lateral displacement between the center points of the partial holes of the laser through hole in the electrically insulating layer structure and of the windows which run through the electrically conductive layer structures on the front side and the rear side. With a sufficiently small offset value (preferably less than 15 μm), a high electrical reliability of the laser through hole filled with electrically conductive material can be achieved.

According to an exemplary embodiment of the invention, a production method for producing a component carrier with a through-hole is provided, wherein the reliability of the through-hole (which can be at least partially filled with electrically conductive material) is high. Conventionally, it can happen that during the formation of the through hole by a combined laser drilling from a front side and from a rear side of an electrically insulating layer structure, a significant lateral overhang of one or both of the electrically conductive layer structures on the opposite main surfaces of the electrically insulating layer structure via an adjacent side wall of the through hole occurs in the electrically insulating layer structure. Conventionally, this can lead to reliability problems when the through hole is filled with electrically conductive material. If such an overhang is excessively large, in particular a beak-shaped gap at an interface between the respective electrically conductive layer structure and the electrically insulating layer structure can be used during a metallization process or the like to fill the Through holes with electrically conductive material remain partially unfilled. As a result, the reliability of the electrical connection provided by the metal-filled through hole can be poor. Exemplary embodiments of the invention, however, are based on the knowledge that if a laser (beam) diameter when drilling on the rear is chosen to be smaller than a laser beam diameter when drilling on the front, the correspondingly configured window in the first electrically conductive layer structure on the front can be larger than one Windows in the electrically conductive layer structure on the back. This, in turn, can have a positive effect on suppressing excessive overhang. Correspondingly (mutatis mutandis), this can also apply to other methods of forming the through hole, for example with the aid of a plasma. In addition, if the first window in the first electrically conductive layer structure on the front side is chosen to be larger than the second window in the second electrically conductive layer structure on the rear side, the requirement can be met according to an exact alignment of the laser device with respect to the preform of the component carrier during laser drilling relax from the front and the back. Conventionally, it is advantageous if a lateral offset between the electrically insulating layer structure and the laser device when drilling from the front and from the rear is as small as possible. Otherwise, an excessive overhang can result. According to an exemplary embodiment of the invention, which carries out a manufacturing architecture for forming a larger front window than a rear window, it has been found, however, that even with a larger offset value between the electrically insulating layer structure and the laser device, when drilling from the front and from the rear, a sufficiently small overhang of 10 μm or less can be achieved. This relaxed requirement regarding the control of the offset can also make the manufacturing architecture simple and accurate according to an exemplary embodiment of the invention.

To put it graphically, if the window of the electrically conductive layer structure on the rear is smaller than the window of the electrically conductive layer structure on the front, then even a certain offset from the front with respect to the rear will occur between the parts of the from the front and the Back drilled through hole, respectively, will not lead to a significant overhang, in particular will not lead to a significant overhang on the front (see also 5 and 6 ). As a result, high electrical reliability can be achieved even if there is some offset.

According to an exemplary embodiment, two different diameters of the upper and lower windows, which extend through electrically conductive layer structures, are set. The diameter at the bottom can preferably be smaller than the diameter at the top. By taking this measure, a potential reliability risk due to problems with top-to-bottom registration (top-to-bottom-side registration) can be solved and even tight specifications can be met. This may even be possible without modification to a laser machine that is used to form a through-hole by front and back drilling. In particular, by using different diameters between the window sizes on the top and bottom, a corresponding manufacturing architecture can help to reduce the effects of a problem with the registration shift. In this way, it may be possible to ensure that a through hole still remains within a predefined specification. At the same time, it may be possible to improve the reliability of the component carrier produced. The simple measures taken in accordance with an exemplary embodiment of the invention can reduce the effort and time for producing a component carrier, since existing hardware can be used with a relatively simple change in terms of processing. Exemplary embodiments of the invention can advantageously be implemented for essentially any electronic application in which through holes are used to achieve an improvement in the reliability of a component carrier produced.

Further exemplary embodiments of the component carrier and of the method are explained below.

In one embodiment, a difference between the widths of the first window and the second window lies in a range between 5 μm and 50 μm, in particular in a range between 10 μm and 30 μm. Accordingly, a difference between the widths of the first laser beam that performs the first laser drilling and the second laser beam that performs the second laser drilling can be in a range between 5 μm and 50 μm, in particular in a range between 10 μm and 30 μm . If the difference between the widths of the windows in the electrically conductive Layer structures on the front and the back become too small, the effects on the reduced overhang and the reduced requirements regarding alignment accuracy are too small. However, if the difference between the windows in the electroconductive layer structures on the front and the back becomes too large, the shape of the laser through hole becomes too asymmetrical, which also deteriorates the improvements in terms of electrical reliability and the lower requirements for alignment accuracy can. Therefore, a difference between the window size on the front side and the window size on the rear side of 5 μm to 50 μm, preferably between 10 μm and 30 μm, is particularly advantageous.

In one embodiment, the width of the first window is in a range between 50 μm and 200 μm, in particular in a range between 65 μm and 120 μm. Accordingly, the width of the first laser beam can be in a range between 50 μm and 200 μm, in particular in a range between 65 μm and 120 μm. The above-mentioned effects due to the size differences between the first window and the second window are particularly pronounced when the absolute value of the first window on the front lies in the ranges mentioned. In general, if the ratio between the difference in the width of the first window and the second window on the one hand and the absolute value of the opening size of the first window on the other is in a range between 10% and 30%, a high influence on the electrical reliability can be achieved .

In one embodiment, the width of the second window is in a range between 40 μm and 150 μm, in particular in a range between 45 μm and 100 μm. Accordingly, the width of the second laser beam can be in a range between 40 μm and 150 μm, in particular in a range between 45 μm and 100 μm. A ratio between the width of the first window and the width of the second window can preferably be greater than 1 and not greater than 1.6, preferably in a range between 1.1 and 1.5, in order to achieve very good results.

In one embodiment, the overhang of the first electrically conductive layer structure and the second electrically conductive layer structure over each side wall of the laser through hole in the electrically insulating layer structure is in each case not more than 20 μm, in particular not more than 15 μm, in particular not more than 10 μm. In other words, the cited values of the overhang can be present both at the interface between the first electrically conductive layer structure and the electrically insulating layer structure and also between the second electrically conductive layer structure and the electrically insulating layer structure, in both cases around the circumference of the laser Through hole around. A suitable electrical reliability of the component carrier can be achieved in particular if all the values of the overhang on the front and the back are less than 20 μm. However, even more pronounced reliability can be achieved if all of these overhang values are below 15 µm or, more preferably, below 10 µm. It is consequently advantageous that the process parameters are selected accordingly when the first window and the second window are formed.

In one embodiment, the overhang of the first electrically conductive layer structure over at least one, in particular over each side wall is not more than 10 μm. If the overhang is less than 10 µm around the entire circumference of the laser through hole on the front side, the component carrier obtained shows high electrical reliability. It has been found that the front overhang in particular is critical for reliability, especially with a certain lateral offset.

In one embodiment, the component carrier consists of electrically conductive filler material that fills at least part of the laser through hole. The electrically conductive material can preferably have copper or consist of copper. In one embodiment, the entire laser through hole is filled with copper. In another embodiment, only a part of the laser through hole is filled with copper. The filling of the laser through hole with electrically conductive material can be achieved by first forming a thin seed layer made of electrically conductive material on the side walls of the electrically insulating layer structures that delimit the laser through hole. Such a seed layer can e.g. may be formed by electroless plating or sputtering to prepare the laser via for a subsequent metallization process. One or more metallizations can then be performed to first thicken the sidewall cover with electrically conductive material, followed by the formation of a bridge connecting the opposite sidewalls in a substantially horizontal direction. After that, the remaining recesses above and below the bridge structure can be filled with further electrically conductive filling medium, such as copper.

In one embodiment, the electrically conductive filler material comprises a bridge structure that connects opposite side walls of the electrically insulating layer structure that delimits the laser through hole. In connection with the present application, the term “bridge structure” can in particular refer to an electrically conductive structure that is essentially horizontal between opposite ones Extends sidewalls of the electrically insulating layer structure and delimits the laser through hole, in particular at or near a narrowest section of the laser through hole. Such a bridge structure can be formed, for example, by metallization after the laser through-hole formation. According to such a metallization method, the previously formed laser through hole is only partially filled with electrically conductive material that forms the bridge structure, so that the bridge structure can be delimited in the upward direction by a first delimitation surface and on another side by a second delimitation surface . Both the first boundary surface and the second boundary surface can have a concave shape.

In one embodiment, the narrowest vertical thickness of the bridge structure is at least 20 μm. It has been found that, in particular, component carriers with laser through holes in thin electrically insulating layer structures of 100 μm thickness or less are particularly susceptible to reliability problems. This appears to be due to the shape of a laser through-hole that extends completely through such thin electrically insulating layer structures, such as thin cores. However, it has surprisingly been found that when the narrowest vertical thickness of the bridge structure connecting the opposite side walls of the electrically insulating layer structure that delimits the laser through hole is 20 μm or more, such reliability problems no longer occur (even if the laser Through hole is formed in a thin electrically insulating layer structure with a thickness of not more than 100 µm). Thus, the aforementioned design rule significantly improves the reliability of copper-filled laser vias, particularly but not limited to thin cores.

In one embodiment, at least a part of the laser through hole is substantially X-shaped in a cross-sectional view. A substantially X-shaped laser through hole can be achieved by a single laser shot when drilling the front and a single laser shot when drilling the back. While conventional filling of such an X-shaped laser through-hole was a challenge, particularly in the narrowest section of such a laser through-hole, such challenges become more relaxed when the laser drilling described is carried out with a larger drilling window from the rear than compared to the front.

Accordingly, the first laser drilling can consist of one laser shot and the second laser drilling can also consist of only one laser shot. Taking this measure can be particularly useful in the case of thinner electrically insulating layer structures (for example with a thickness of less than 100 μm). Such an approach with two laser shots can lead to an X-shape of the laser through hole with little effort (cf. 2nd ).

In another embodiment, at least part of the laser through hole has a central, substantially cylindrical section between two opposite, tapered sections. With such an alternative approach, the narrowest section of the laser through hole can be made wider or wider from the rear by an additional third laser shot. In other words, a laser through hole with the described geometry can be achieved by first performing a laser shot for front-side drilling and then two laser shots for back-side drilling. This approach can further improve electrical reliability (cf. 3rd ).

Accordingly, the first laser drilling can comprise one laser shot and the second laser drilling two laser shots. This measure can be particularly useful for thicker electrically insulating layer structures (e.g. with a thickness of more than 100 µm). Such an approach with three laser shots can result in a geometry with two outer, tapered sections, which are connected by a straight central section of the laser through hole. The straight section can have different vertical lengths on different side walls.

In one embodiment, the laser through hole has an offset from the front with respect to the rear of not more than 20 μm, in particular in a range between 15 μm and 20 μm. In connection with the present application, the term “offset from the front with respect to the rear” (“front-side-to-back-side offset”) can in particular mean a lateral displacement between the centers (or centers) of the laser beams (and consequently the Designate partial holes of the laser through hole) when drilling from the front and when drilling from the rear. With an offset value of even less than 20 µm, a high electrical reliability of the laser through hole filled with electrically conductive material can be achieved, because thanks to the larger window that arises when drilling from the front than compared to the window that arises when drilling from the rear . A small offset can e.g. by clamping a preform of the component carrier (e.g. a plate) on a mounting base during laser drilling.

Particularly when embedding components (such as semiconductor chips with solder pads), the requirements for the electrical reliability of the component carrier are particularly pronounced, since such embedded components may require an electrical connection from the front and / or from the rear. The aforementioned laser through holes filled with electrically conductive material can contribute to such an electrical connection. Therefore, the improved accuracy and reliability of the electrically conductive filling of the laser through hole leads to an improved reliability in the embedding of components in the component carrier.

In one embodiment, the first laser drilling is carried out with a lower laser power than the second laser drilling. It has been found that if the laser power when drilling from the front (with a larger window size) is chosen to be lower than the laser power that is used when a smaller window is formed on the rear, the influence on the reduction of the overhang and thus the improvement of the electrical power Reliability is particularly high. In other words, the formation of a large window can advantageously be carried out with a smaller laser power than the formation of a smaller window. Surprisingly, this combination of parameters (i.e. larger laser beam size with lower power when drilling on the front compared to higher laser power with a smaller laser beam size when drilling on the rear) can lead to a further improvement in electrical reliability by reducing the overhang.

• - In einer Ausführungsform wird das erste Laserbohren mit einer geringeren Laserenergie als das zweite Laserbohren durchgeführt, so dass der lateral schmalste Abschnitt des Durchgangslochs näher an der Vorderseite als an der Rückseite liegt. So kann sich der schmalste Abschnitt des Durchgangslochs näher an der oberen Hauptoberfläche befinden bei einem weichen ersten Schuss von der oberen Hauptoberfläche mit größerem Durchmesser, gefolgt von einem stärkeren zweiten Schuss von der unteren Hauptoberfläche mit kleinerem Durchmesser. Infolgedessen kann ein mittiger oder schmalster Abschnitt des Durchgangslochs nach unten verschoben werden.
• - In einer anderen Ausführungsform wird das erste Laserbohren mit einem ersten Laserschuss von der Vorderseite mit einer kleineren Energie und einem größeren Laserdurchmesser als ein nachfolgender zweiter Laserschuss von der Vorderseite durchgeführt, gefolgt von dem zweiten Laserbohren von der Rückseite mit einem weiteren Laserschuss mit einem kleineren Laserdurchmesser als dem des ersten Laserschusses und größer als dem des zweiten Laserschusses, so dass der lateral schmalste Abschnitt der Durchgangsbohrung näher an der Rückseite als an der Vorderseite liegt. So kann einem ersten oberseitigen Schuss mit großem Durchmesser und niedriger Energie ein zweiter oberseitiger Schuss mit kleinerem Durchmesser und höherer Energie folgen (der tiefer geht, ohne die Seitenwände des geöffneten Hohlraums zu entgraten und ohne einen größeren Überhang zu erzeugen). Anschließend kann ein dritter Schuss als erster unterseitiger Schuss mit kleinerem Durchmesser erfolgen, um mit dem zuvor geformten Sackloch zu verbinden. Auf diese Weise kann ein mittiger oder schmalster Abschnitt des Durchgangslochs nach unten verschoben werden.

In one embodiment, a laterally narrowest section of the through hole can be arranged vertically asymmetrically to the front and the rear, in particular closer to the front than to the rear or closer to the rear than to the front. Accordingly, the first laser drilling and the second laser drilling can be carried out so that a laterally narrowest portion of the through hole is vertically asymmetrical to the front and the back. Thus, the narrowest section of the through hole can be asymmetrical, namely not in the middle of the through hole, but rather on the top or the bottom. This can be set by appropriately configuring the laser energy, the laser diameter and the number of shots from the front and the back:

• In one embodiment, the first laser drilling is carried out with a lower laser energy than the second laser drilling, so that the laterally narrowest section of the through hole is closer to the front than to the rear. For example, the narrowest portion of the through hole may be closer to the upper major surface with a soft first shot from the larger diameter upper major surface, followed by a stronger second shot from the smaller diameter lower major surface. As a result, a central or narrowest section of the through hole can be shifted downward.
• In another embodiment, the first laser drilling with a first laser shot from the front is carried out with a smaller energy and a larger laser diameter than a subsequent second laser shot from the front, followed by the second laser drilling from the rear with a further laser shot with a smaller laser diameter than that of the first laser shot and larger than that of the second laser shot, so that the laterally narrowest section of the through hole is closer to the rear than to the front. Thus, a first top shot with a large diameter and low energy can be followed by a second top shot with a smaller diameter and higher energy (which goes deeper without deburring the side walls of the open cavity and without creating a larger overhang). A third shot can then be made as the first underside shot with a smaller diameter in order to connect to the previously formed blind hole. In this way, a central or narrowest section of the through hole can be moved downward.

Such a geometry of the through hole, when a metallization process is carried out, can also lead to the formation of a bridge structure which laterally connects opposite side walls of the electrically insulating layer structure which delimits the through hole in a vertical plane in which the distance to the first main surface is different from that Distance to the second main surface differs. This can promote the formation of a free hanging, asymmetrical bridge structure that is located outside a vertical center of the through hole.

In one embodiment, the first laser drilling is carried out with a shorter time period than the second laser drilling. In such an embodiment, it is also possible to keep the laser power constant during the front-side drilling and the rear-side drilling, but to adjust the time setting by adjusting the time length of the laser pulse that is radiated onto the preform of the component carrier.

In one embodiment, the component carrier consists of a stack of at least one electrically insulating layer structure and at least one electrically conductive layer structure. The component carrier can be, for example, a laminate of the electrically insulating layer structure (s) mentioned and the electrically conductive layer structure (s), which is formed in particular by registering mechanical pressure and / or thermal energy. The stack mentioned can provide a plate-shaped component carrier which offers a large fastening surface for further components and is nevertheless very thin and compact.

In one embodiment, the component carrier is designed as a plate. This contributes to the compact design, the component carrier nevertheless providing a large base for fastening components thereon. In addition, in particular an exposed chip (naked die), as an example of an embedded electronic component, can, due to its small thickness, be suitably inserted into a thin plate, such as e.g. a circuit board to be embedded.

In one embodiment, the component carrier is configured as one of the group consisting of a printed circuit board and a substrate (in particular an IC substrate).

In connection with the present application, the term “printed circuit board” (PCB) can in particular refer to a plate-shaped component carrier which is formed by laminating a plurality of electrically conductive layer structures with a plurality of electrically insulating layer structures, for example by applying pressure and / or by supplying thermal energy. As preferred materials for printed circuit board technology, the electrically conductive layer structures consist of copper, while the electrically insulating layer structures can consist of resin and / or glass fibers, so-called prepreg, such as FR4 material. The various electrically conductive layer structures can be interconnected as desired by forming through holes through the laminate, e.g. by laser drilling or mechanical drilling, and these are filled with electrically conductive material (in particular copper), whereby vias are formed as through-hole connections. Aside from one or more components that can be embedded in a printed circuit board, a printed circuit board is usually configured such that it can receive one or more components on one or both opposite surfaces of the plate-shaped printed circuit board. They can be connected to the respective main surface by soldering. A dielectric part of a circuit board can be made of resin with reinforcing fibers (such as glass fibers).

In connection with the present application, the term “substrate” can in particular denote a small component carrier which is essentially the same size as a component to be mounted thereon (in particular an electronic component). More specifically, a substrate can be understood as a carrier for electrical connections or electrical networks and as a component carrier that is comparable to a printed circuit board (PCB), but with a much higher density of laterally and / or vertically arranged connections. Lateral (or lateral) connections are e.g. Conductor tracks, whereas vertical connections e.g. Holes can be. These lateral and / or vertical connections are arranged within the substrate and can be used to make electrical and / or mechanical connections between housed components or non-housed components (such as exposed chips), in particular IC chips, with a circuit board or intermediate circuit board to manufacture. The term “substrate” therefore also includes “IC substrates”. A dielectric part of a substrate can be made of resin with reinforcing balls (such as glass balls).

In one embodiment, the at least one electrically insulating layer structure comprises at least one from the group consisting of: resin (such as reinforced or non-reinforced resins, for example epoxy resin or bismaleimide-triazine resin), cyanate ester, polyphenylene derivative, glass (in particular glass fibers, multi-layer glass, glass-like materials), prepreg material (such as FR-4 or FR-5), polyimide, polyamide, liquid crystal polymer (LCP), build-up film (build-up film) based on epoxy, polytetrafluoroethylene (Teflon), a ceramic and a metal oxide. Reinforcing materials such as fabrics, fibers or spheres, e.g. made of glass (multilayer glass) can be used. Although prepreg, in particular FR4, is generally preferred for rigid printed circuit boards, other materials, in particular epoxy-based build-up films for substrates, can also be used. For high-frequency applications, high-frequency materials, such as polytetrafluoroethylene, liquid crystal polymer and / or cyanate ester resins, low-temperature fired ceramics (LTCC, low temperature cofired ceramics) or other low, very low or ultra-low DK materials can be incorporated into the component carrier as an electrically insulating layer structure .

In one embodiment, at least one of the electrically conductive layer structures comprises at least one from the group consisting of: copper, aluminum, nickel, silver, gold, palladium and tungsten. Although copper is usually preferred, other materials are also coated Versions of these are possible, in particular coated with superconducting material, such as graphene.

The at least one component can be selected from a group consisting of: an electrically non-conductive insert, an electrically conductive insert (such as a metal insert, preferably made of copper or aluminum), a heat transfer unit (eg a heat pipe), a light-conducting element (e.g. an optical waveguide or a light guide connection, an electronic component or combinations thereof). The component can be, for example, one of the following: an active electronic component, a passive electronic component, an electronic chip, a memory device (for example a DRAM or another data storage device), a filter, an integrated circuit, a signal processing component, a power management component, an optoelectronic component Interface element, a light emitting diode, a photocoupler, a voltage converter (e.g. a DC / DC converter or an AC / DC converter), a cryptographic component, a transmitter and / or receiver, an electromechanical converter, a sensor, an actuator, a microelectromechanical System (MEMS), a microprocessor, a capacitor, a resistor, an inductor, a battery, a switch, a camera, an antenna, a logic chip and a power generation unit. However, other components can be embedded in the component carrier. For example, a magnetic element can be used as a component. Such a magnetic element can be a permanent magnetic element (e.g. a ferromagnetic element, an antiferromagnetic element, a multiferro element or a ferrimagnetic element, e.g. a ferrite core) or can be a paramagnetic element. The component can also be a substrate, an intermediate carrier (interposer) or another component carrier, for example in a board-in-board configuration. The component can be surface-mounted on the component carrier and / or embedded in an interior of the component carrier.

In one embodiment, the component carrier is a laminate-type component carrier. In such an embodiment, the component carrier is a composite of a plurality of layer structures which are stacked and connected to one another by registering pressure force and / or heat.

The substrate or the intermediate carrier can consist of at least one layer of glass, silicon (Si) or a photo-imaging or dry-etchable organic material, such as build-up films based on epoxy or polymer compounds such as polyimide, polybenzoxazole or benzocyclobutene.

• Die 1 bis 4 zeigen Querschnittsansichten von Strukturen, die erhalten werden bei der Durchführung von Verfahren des Herstellens eines Bauteilträgers mit einem metallisierten Laser-Durchgangsloch, wie in 4 dargestellt, durch eine Behandlung mit mehrfachen Laserschüssen von entgegengesetzten Seiten und durch nachfolgende Verfahren des Füllens des Laser-Durchgangslochs mit elektrisch leitfähigem Material entsprechend einer beispielhaften Ausführungsform der Erfindung.
• 5 zeigt eine Querschnittsansicht von Bauteilträgern mit Laserdurchgangslöchern, die bei der Durchführung herkömmlicher Fertigungsverfahren erhalten werden.
• 6 zeigt eine Querschnittsansicht von Bauteilträgern mit Laser-Durchgangslöchern, die bei der Durchführung eines herkömmlichen Herstellungsverfahrens und eines Herstellungsverfahrens gemäß einer beispielhaften Ausführungsform der Erfindung erhalten werden.

The aspects defined above and further aspects of the invention are evident from the examples of embodiments to be described below and are explained with reference to these examples of embodiments.

• The 1 to 4th show cross-sectional views of structures obtained when performing methods of manufacturing a component carrier with a metallized laser through hole, as in 4th shown by treatment with multiple laser shots from opposite sides and by subsequent methods of filling the laser through hole with electrically conductive material according to an exemplary embodiment of the invention.
• 5 shows a cross-sectional view of component carriers with laser through holes, which are obtained in the implementation of conventional manufacturing processes.
• 6 FIG. 14 shows a cross-sectional view of component carriers with laser through holes that are obtained by performing a conventional manufacturing method and a manufacturing method according to an exemplary embodiment of the invention.

The illustrations in the drawings are schematic. In different drawings, similar or identical elements are provided with the same reference symbols.

Before exemplary embodiments are described in more detail with reference to the drawings, some fundamental considerations are summarized, on the basis of which exemplary embodiments of the invention have been developed.

According to an exemplary embodiment of the invention, an improvement in reliability can be achieved by the shape of a laser-drilled through hole, which makes it possible to solve a problem with a registration between the top and the bottom (top-to-bottom registration). The latter can conventionally arise as a result of a lateral (or lateral) mismatch between the center points of the partial holes, which together form the laser through hole. Such a lateral mismatch can also be referred to as an offset. An exemplary embodiment of the invention essentially consists in resolving a small average diameter, which is conventionally caused by a problem of shifting from top to bottom (top-to-bottom via shift) and can conventionally lead to a reliability risk of the finished component carrier.

In general, the diameter of a window in an electrically conductive layer structure on the underside of an electrically insulating layer structure is conventionally equal to the corresponding diameter of a corresponding window in a corresponding electrically conductive layer structure on the top side. It has been conventionally believed that such a design can result in perfect X-bridging in copper plating. However, this requires a very high accuracy of fit between the top and the bottom.

According to an exemplary embodiment of the invention, the diameter of the window that extends through the electrically conductive layer structure on the underside can be selected to be smaller than the diameter of the window that extends through the other electrically conductive layer structure on the top side. It has been found that such a manufacturing architecture can make it possible to obtain a wider window of the fit requirement. Even with an offset between the top and bottom between the center of the conical portion of the laser through hole on the top and the conical portion of the laser through hole on the bottom, for example, 15 µm, the laser through hole can still be formed in a suitable shape without the risk of inclusions or voids within an electrically conductive filling medium (such as copper) which fills the laser through hole due to a large overhang or a small central (or medium) diameter. An exemplary embodiment of the invention therefore introduces an opening diameter on the underside of said window that is selectively smaller (in particular outside tolerances) than an opening diameter on the top side. Such a manufacturing architecture can be described clearly as a non-center X-shaped hole.

It has been found that such wider operating windows for accuracy of fit (or coverage) significantly reduce the risk of undesired inclusions and can significantly improve electrical reliability. This can advantageously be achieved essentially without serious hardware changes or software changes to existing machines.

In particular, exemplary embodiments of the invention can be used for HDI (High Density Integration) any layer designs (anylayer designs) with a core. After laser drilling, the through hole can be filled with copper plating. Any conventional laser machine can be used to advantage to implement laser through hole technology without hardware upgrade. In addition, exemplary embodiments of the invention can enable a higher number of laser holes per plate without increasing the risk of reliability.

With the introduction of laser through hole technology in component carrier manufacturing, the problem of top to bottom misalignment was a critical factor affecting the quality of printed circuit boards or other types of component carriers. The requirement to control the top to bottom offset within 10 µm or less has been a challenge with conventionally available equipment (or equipment). Taking measures, such as a mechanical chuck that clamps a plate on the front during laser drilling, and / or offset laser drilling to avoid warping and thereby reduce top to bottom misalignment can help reduce the problem mentioned . However, with the advancement of component carrier technology, with a further reduction in core thickness and an increase in the number of laser through holes required per plate, controlling the offset between top and bottom can become more difficult as the plates become smaller in the laser drilling process. Exemplary embodiments of the invention can enable larger operating windows and increase the electrical reliability of the component carriers produced, with or without mechanical clamping. The value (or size) of the overhang on the top and / or the bottom can be significantly reduced by exemplary embodiments of the invention.

The 1 to 3rd show cross-sectional views of structures that are obtained when performing methods for producing a component carrier 100 with a laser through hole 112 , as in 2nd and 3rd represented by treatment with multiple laser shots from opposite sides according to an exemplary embodiment of the invention. 4th shows the correspondingly trained component carrier 100 after filling the laser through hole 112 with electrically conductive filling medium 126 , preferably copper.

With reference to 1 is a first laser shot that is a first laser beam 138 corresponds, from a front to an electrically insulating layer structure 102 directed on the two opposite main surfaces 104 , 106 each with an electrically conductive layer structure 108 , 110 is covered.

This is how an electrically insulating layer structure becomes 102 provided, which can be made of resin (such as epoxy resin) and optionally reinforcing particles, such as glass fibers or glass balls. The electrically insulating layer structure 102 can, for example, be made from fully hardened FR4 material, ie material with resin that is already fully cross-linked and is not able to remelt or become flowable by applying mechanical pressure and / or heat. The first main surface 104 on the front of the electrically insulating layer structure 102 is made of a first electrically conductive layer structure 108 covered, which may be a metal layer, such as a copper foil. The opposite second main surface 106 on the back of the electrically insulating layer structure 102 can with a second electrically conductive layer structure 110 covered, which can also be a metal layer, such as a copper foil.

A vertical thickness D of the electrically insulating layer structure 102 can be relatively small, for example less than 100 µm (more precisely in a range between 40 µm and 60 µm). It has been found that the formation of laser through holes through such a thin electrically insulating layer structure 102 or a core is particularly difficult when it comes to reliability problems caused by phenomena such as excessive overhang 122 can be caused, which is described in more detail below. The first electrically conductive layer structure 108 and the second electrically insulating layer structure 110 can be metal layers, each having a thickness d1 and d2 of, for example, less than 5 µm, in particular between 2 µm and 4 µm.

A stack 159 that from the layer structures 102 , 108 , 110 can exist from the front through the first electrically conductive layer structure 108 and in the electrically insulating layer structure 102 be drilled. As a result, a first window appears 114 as a through hole in the first electrically conductive layer structure 108 educated. In addition, in the electrically insulating layer structure 102 in one to the first main surface 104 adjacent area a blind hole 136 educated. The blind hole 136 is through side walls 124 the electrically insulating layer structure 102 limited. This first laser drilling can be done with a first laser beam 138 with a diameter or a width of 148 be carried out, which is preferably in a range between 65 microns and 120 microns. As a result of the first laser drilling, a lateral overhang, which is schematically identified by the code number 122 is indicated as beak-shaped pockets in the blind hole 136 be generated. The overhang 122 is located at an interface between the first window 114 that in the structured first electrically conductive layer structure 108 is formed, and an upper portion of the electrically insulating layer structure 102 . Expressed clearly, the structured first electrically conductive layer structure can 108 with their first window 114 laterally over the electrically insulating layer structure 122 extend beyond an amount equal to the overhang 122 corresponds.

As in 1 is shown in the first electrically conductive layer structure 108 through the first laser beam 138 with a width 148 , which is generated by a laser source, a through hole as the first window 114 with a lateral width 120 of, for example, between 65 µm and 120 µm. This first laser shot also forms the blind hole 136 in the electrically insulating layer structure 102 . When laser processing from the front or the first main surface 104 care should be taken that the laser power is selected to be sufficiently small and / or the first laser shot is so short that the blind hole 136 not up to the second electrically conductive layer structure 110 extends. In such a case, undesirable phenomena, such as the reflection of the laser on the second electrically conductive layer structure, can occur 110 , occur, the electrical power of the component carrier produced 100 can deteriorate.

With reference to 2nd A second laser shot can be performed using a laser source that emits a second laser beam 140 towards the bottom of the stack 159 sends out to the second electrically conductive layer structure 110 to open and further dielectric material of the electrically insulating layer structure 102 to remove from the bottom.

Although not shown in the figures, the stack can 159 after the in 1 described methods are turned (ie rotated by 180 °) before the second laser drilling through the second electrically conductive layer structure 110 and through the electrically insulating layer structure 102 from the back or the second main surface 106 is carried out. This measure can prevent the laser source from the top to the bottom of the stack 159 must be moved.

The second laser shot creates a second window 116 formed by the second electrically conductive layer structure 110 extends. In addition, the second laser shot can cause additional material of the electrically insulating layer structure 102 be removed to the blind hole 136 into a laser through hole 112 to expand that through the entire thickness of the electrically insulating layer structure 102 extends. How has shown the second window 116 a lateral width 118 that is smaller than the lateral width 120 of the first window 114 . This results from the fact that the second laser beam 140 a lateral width 150 that is smaller than the lateral width 148 of the first laser beam 138 . The width 118 and the width 150 can, for example, each be in a range between 45 µm and 100 µm.

The first laser drilling (described with reference to 1 ) with a wider first laser beam 138 be performed as the second laser drilling (described with reference to 2nd ) with a narrower second laser beam 140 is carried out. A difference between the latitudes 148 , 150 of the first laser beam 138 who performs the first laser drilling and the second laser beam 140 who performs the second laser drilling can preferably be in a range between 10 microns and 30 microns. Accordingly, there can be a difference between the widths 118 , 120 of the first window 114 in the first electrically conductive layer structure 108 and the second window 116 in the second electrically conductive layer structure 110 are preferably in a range between 10 microns and 30 microns. Advantageously, the width 150 of the second laser beam 140 can be smaller than the width 148 of the first laser beam 138 . Accordingly, the width 120 of the first window 114 be larger than the width 118 of the second window 160 .

As a result of the described production method, an interface between the second electrically conductive layer structure can also be used 110 on the one hand and the electrically insulating layer structure 102 on the other hand in the area of the second window 116 a certain overhang 122 be generated. The overhang 122 the first electrically conductive layer structure 108 and the second electrically conductive layer structure 110 over the side walls 124 the electrically insulating layer structure 102 that the laser through hole 112 limited, preferably may not be more than 10 microns. A detail 175 shows the overhang 122 for the example of the top left of 2nd . The corresponding definition of the overhang 122 can also be on the top right and bottom of 2nd be applied.

In addition, a lateral offset (see reference number 134 in 6 ) as the lateral distance between the center of the first window 114 and the middle of the second window 116 be generated. Such a lateral offset 134 can also be present between a center of a first tapered section 130 in the electrically insulating layer structure 102 and originate from the first laser drilling and a center of a second tapered section 132 in the electrically insulating layer structure 102 and come from the second laser drilling.

It turned out that if the second window 116 with a smaller width 118 than the width 120 of the first window 114 is formed, even a certain offset 134 not an excessive overhang 122 leads, especially in the first electrically conductive layer structure 108 . As a result, high electrical reliability (caused by excessive overhang 122 can be negatively influenced) of the finished component carrier 100 after filling the laser through hole 112 with electrically conductive filling medium 126 can be achieved (see 4th ) when back laser drilling with a second laser beam 140 is carried out of a smaller width 150 than the width 148 of the laser beam used for front drilling 138 Has.

Surprisingly, when trying to overhang 122 Keeping it small has proven to be very helpful if the first laser drilling is carried out with a lower laser power than the second laser drilling.

After the first laser drilling with a laser shot from the front (see 1 ) and the second laser drilling with just one more laser shot from the back (see 2nd ) has been completed, a substantially X-shaped laser through hole 112 , as in 2nd shown, then partially or entirely with electrically conductive filling medium 126 be filled (see 4th ). The electrically conductive filling medium 126 can be achieved by electroless plating in combination with galvanic coating using the in 2nd structure as a starting point. The embodiment of 2nd is particularly advantageous when a simple manufacturing process is desired, since only two laser shots are sufficient around the essentially X-shaped laser through hole 112 to figures.

Alternatively, a second laser shot can be performed from the underside, whereby the in 3rd Shown shape of the laser through hole 112 arises. In an alternative embodiment, such a structure can serve as the basis for filling the laser through hole 112 with electrically conductive filling medium 126 be used. The formation of a laser through hole 112 with such a geometry is described below with reference to 3rd described in more detail.

With reference to 3rd an additional third laser shot (or a second laser shot from the back) can be performed from the bottom to the center (or center) diameter of the laser hole 112 to open further. Expressed vividly, the narrowest section of the laser through hole can 112 in 2nd with the third laser shot, like the one in 3rd is shown. This can help to further improve the electrical reliability as it is filling the laser through hole 112 with electrically conductive filling medium 126 simplified. In the embodiment of 3rd includes or is the first laser drilling from the front (see 1 ) So only from one laser shot, and the second laser drilling from the back (see 2nd and 3rd ) comprises or consists of two laser shots. As a result of the additional third laser shot, which in 3rd is shown, the obtained laser through hole 112 a central, substantially cylindrical section 128 between the two opposite, tapered sections 130 , 132 on.

Thus, the embodiment differs from 3rd from the embodiment of 2nd in that an additional third laser shot from the back or the second main surface 106 is carried out. This third laser shot causes the in 2nd general X shape shown in the in 3rd shown shape is expanded, the substantially cylindrical central portion 128 of the laser through hole 112 , that with two opposite, tapered sections 130 , 132 on the front side 104 or on the back 106 connected is.

4th shows a cross section of the component carrier 100 based on the in 3rd shown preform after filling the laser through hole 112 with electrically conductive filling medium 126 was obtained. Although the process of filling the laser through hole 112 with electrically conductive filling medium 126 hereinafter based on the in 3rd shown geometry of the laser through hole 112 is alternatively described, the X-shaped laser through hole 112 according to 2nd be used in a corresponding manner as the basis for this filling process. Therefore, the following describes how the electrically conductive filling medium 126 , preferably copper, in the in 3rd shown laser through hole 112 is trained.

To achieve this, it is preferable to first perform an electroless plating process, thereby creating a thin seed layer 144 from copper to figures that directly the side walls 124 the electrically insulating layer structure 102 that covered the laser through hole 112 limited. This is in one detail 121 in 4th to see. A thickness of the seed layer 144 can be, for example, 0.5 µm. But it is also possible that the seed layer 144 has a thickness of more than 1 μm and / or that several cumulative seed layers are provided. For example, the thickness of a seed layer or a cumulative thickness of several seed layers can be in a range between 0.5 μm and 5 μm. If several seed layers are provided, they can have an organic (eg polymer) layer, a palladium layer and / or a copper layer. The formation of the seed layer 144 can promote a subsequent electroplating process as described below.

Subsequently, further electrically conductive material (eg copper) can be placed on the seed layer 144 be deposited by a metallization process, in particular by galvanization or galvanic deposition. So the germ layer 144 on the side walls 124 as well as the electrically conductive layer structures 108 , 110 with a metallization layer 146 made of electrically conductive filling medium 126 such as copper. The metallization layer 146 can have a minimum thickness of 10 µm, for example.

During the described metallization process of forming, formation of the metallization layer 146 can be an electrically conductive bridge structure 180 in one piece with the metallization layer 146 can be formed as a substantially horizontal section, the opposite side walls 124 of the laser through hole 112 connects. As shown, the electrically conductive bridge structure 180 formed so that it has a concave upper first boundary surface 182 that are oriented upwards or the first main surface 104 is facing, and by a concave lower second boundary surface 184 that are oriented downwards or the second main surface 106 is facing, is limited. The formation of the electrically conductive bridge structure 180 can by galvanic metallization together with the metallization layer 146 take place, preferably after the formation of the seed layer 144 . The bridge structure 180 forms a substantially horizontal bridge between the opposite side walls 124 the electrically insulating layer structure 102 that the laser through hole 112 in the narrowest part of the laser through hole 108 limited.

The narrowest vertical thickness w of the bridge structure is preferably 180 at least 20 µm. Especially when the thickness D of the electrically insulating layer structure 102 is relatively small (especially less than 100 µm), ensures a minimal vertical thickness w of the bridge structure 180 of 20 µm the proper reliability of the component carrier received 100 .

In addition, there will be a first electrically conductive bulk structure 186 that has a large portion between the first delimitation surface 182 and the first main surface 104 fills in, and a second electrically conductive volume structure 188 that much between the second demarcation area 184 and the second main surface 106 filled out, trained. This can be done by performing one or more further galvanic metallization processes following the previous metallization process to form the bridge structure 180 respectively.

So the component carrier 100 according to 4th can be obtained by one or more further metallization processes. This allows the volume structures 186 , 188 which can be made of copper, for example. In the embodiment shown, it remains on an upper side or a lower side of the component carrier shown 100 a small dip 190 or. 192 . In other embodiments, the volume structures fill 186 , 188 the remaining recesses above the first delimitation area 182 and below the second demarcation area 184 almost completely. It should be said that it is known to a person skilled in the art that the boundary surfaces 182 , 184 are clearly visible when a cross section of the component carrier 100 is mapped.

The obtained as a result of the manufacturing process described and in 4th Component carrier shown 100 thus consists of the electrically insulating layer structure 102 with the front 104 and the back 106 , the structured (or patterned) first electrically conductive layer structure 108 who have the front 104 the electrically insulating layer structure 102 covered, the structured second electrically conductive layer structure 110 who have the back 106 the electrically insulating layer structure 102 covered, and the laser through hole 112 that is through the first window 114 the first electrically conductive layer structure 108 , the electrically insulating layer structure 102 and the second window 116 the second electrically conductive layer structure 110 extends. The laser through hole 112 is with the electrically conductive filling medium 126 filled. As a result of the manufacturing process described, the second window 116 a smaller width 118 than the width 120 of the first window 114 . The difference between the latitudes 118 , 120 of the first window 114 and the second window 116 can preferably be between 10 microns and 30 microns. The width 118 of the first window 114 can preferably be in a range between 65 microns and 120 and be larger than the width 120 of the second window 116 , which is preferably in a range between 45 microns and 100 microns.

As a result of the manufacturing process described, the overhang 122 of both the first electrically conductive layer structure 108 as well as the second electrically conductive layer structure 110 over the side walls 124 of the laser through hole 112 in the electrically insulating layer structure 102 10 µm or less. It is very advantageous that the overhang 122 on the front side 104 and on the back 106 even with a certain offset 134 can be kept sufficiently small. This is because the laser treatment is set to the first window 114 that in the first electrically conductive layer structure 108 is larger than the second window 116 on the back side 106 .

5 shows a cross-sectional view of component carriers 200 with laser through holes 202 that have been obtained by performing conventional manufacturing processes. Expressed vividly shows 5 Defects and problems of conventional laser through holes 202 . Specifically shows 5 Problems with the electrical reliability of a component carrier 200 , which was formed according to a conventional manufacturing method. As shown, the laser through hole 202 shaped so that it is a first electrically conductive layer structure 204 , an electrically insulating layer structure 206 and a second electrically conductive layer structure 208 extends.

Like the one on the left of 5 is shown, only in the unlikely event of a zero shift between the laser drilling on the front and the laser drilling on the back becomes a laser through hole 202 achieved with high performance. However, a zero point shift of all or even many component carriers can 200 that were produced in a batch process cannot be achieved. Therefore the left side of 5 the formation of a laser through hole 202 under perfect or ideal conditions that cannot always be met in practice.

A middle part of 5 illustrates problems with conventional component carriers 200 in terms of significant offset 212 between top and bottom (top-to-bottom offset). In particular, an excessive amount of laser energy during the lower laser shot can result in a long overhang 210 at the top, which has a potential risk of forming undesirable voids or inclusions in an interior of an electrically conductive filling medium (see reference numerals 126 in 4th ) with it when it enters the laser through hole 202 is filled. Like that in the middle part of 5 is shown, the described conventional manufacturing architecture leads to a large overhang, especially on the front 210 in the case of a pronounced offset 212 between front drilling and back drilling. Filling the in the middle part of 5 shown laser through hole 202 with electrically conductive material and without any remaining voids is therefore a major challenge.

The right side of 5 shows a scenario that results from insufficient laser energy and leads to a small central (or medium) diameter, see reference numerals 214 . Inadequate laser energy can lead to a pronounced bottleneck in an interior of the electrically insulating layer structure 206 lead, with an even more undesirable influence on the reliability of the component carrier produced 200 if it is filled with electrically conductive filling medium.

6 shows a cross section of component carriers 200 , 100 with laser through holes 202 , 112 which arises when a conventional manufacturing method (left side) and a manufacturing method according to an exemplary embodiment of the invention (middle part, right side) are carried out.

To the left of 6 is a conventional laser through hole 202 shown with a pronounced offset 212 between top and bottom and windows in the electrically conductive layer structures 204 , 208 on the front and back with the same width. The offset 212 can be, for example, 15 µm to 20 µm. Like the one on the left of 6 is shown, the formation of a laser through hole 202 result in poor performance due to front drilling and back drilling with the same window sizes on the front and rear.

Advantageously, the method according to the exemplary embodiments of the invention, which are in the middle part and on the right side of 6 are shown to be set to have a top diameter or width 120 of the first window 114 is reached at 70 µm while the bottom diameter or width 118 of the second window 116 is reduced to 50 µm.

Just like that in a middle part of 6 is shown when the first window 114 by laser drilling on the front in the first electrically conductive layer structure 108 is formed, a larger dimension or width 120 (70 µm in the present example) compared to the width 118 of the second window 116 that when drilling on the back in the second electrically conductive layer structure 110 is formed, only a very small overhang 122 achieved when the offset 134 is zero (like a vertical line 187 is shown).

The right side of 6 shows an exemplary embodiment of the invention in a more critical scenario with an offset 134 / an offset displacement of approximately 15 μm to the left, ie with a limited offset performance between top and bottom. But even with this offset 134 between top and bottom it will most advantageously not have an excessive overhang 122 and thus there is no risk of inclusions. In addition, there is no risk of reliability due to a small central diameter, as in the conventional approach shown on the left. These advantageous effects can be combined with the further advantageous effect that the accuracy requirements with regard to the control of the offset during front-side drilling and during offset drilling are not very strict according to exemplary embodiments of the invention, since even a certain offset 134 can result in a laser through hole 112 geometry that still ensures high electrical reliability.

6 shows schematically on the right side an electrically conductive filling medium 126 which is a large part of the laser through hole 112 fills out. This in 6 shown filling medium 126 can, for example, in a similar manner as above with reference to 4th described.

In order to achieve adequate reliability, it is preferred that there is a ratio between the maximum overhang 122 on the first electrically conductive layer structure 108 (ie the largest overhang value 122 along the perimeter of the first window 114 ) and the width 120 of the first window 114 is less than 20%. Accordingly, it is preferable that a ratio between the maximum overhang 122 on the second electrically conductive layer structure 110 (ie the largest overhang value 122 along the perimeter of the second window 116 ) and the width 118 of the second window 116 is less than 20%. This greatly suppresses the occurrence of voids when the laser through hole 112 with electrically conductive filling medium 126 has been filled. For example, a nominal value of the opening diameter can be in a range between 70 µm and 85 µm (the overhang 122 can, however, be calculated on the basis of a nominal value of, for example, 70 µm). The design rule mentioned is in detail 199 which represents the value of the maximum overhang 122 with the reference symbol b shows. In this example, the ratio would be the ratio between b and 50 µm.

It should be noted that the term "having" does not exclude other elements or steps, and that "a" or "an" does not exclude a plurality. Elements that have been described in connection with various embodiments can also be combined.

It should be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

The implementation of the invention is not limited to the preferred embodiments shown in the figures and described above. Rather, a large number of variants are possible which use the solutions shown and the principle according to the invention even in fundamentally different embodiments.

Claims (27)

A component carrier (100), the component carrier (100) having: an electrically insulating layer structure (102) with a front side (104) and a back side (106); a first electrically conductive layer structure (108) covering the front side (104) of the electrically insulating layer structure (102); a second electrically conductive layer structure (110) covering the rear side (106) of the electrically insulating layer structure (102); a through hole (112), in particular a laser through hole (112), which extends through a first window (114) of the first electrically conductive layer structure (108), the electrically insulating layer structure (102) and a second window (116) of the second conductive layer structure (110) extends; wherein the second window (116) has a width (118) that is less than another width (120) of the first window (114); and an overhang (122) of at least one of the first electrically conductive layer structure (108) and the second electrically conductive layer structure (110) over at least one side wall (124) of the electrically insulating layer structure (102) which delimits the through hole (112), is not more than 10 µm. The component carrier (100) according to Claim 1 , wherein a difference between the width (120) of the first window (114) and the width (118) of the second window (116) lies in a range between 5 µm and 50 µm, in particular in a range between 10 µm and 30 µm . The component carrier (100) according to Claim 1 or 2nd , wherein a width (120) of the first window (114) lies in a range between 50 µm and 200 µm, in particular in a range between 65 µm and 120 µm. The component carrier (100) according to one of the Claims 1 to 3rd , wherein a width (118) of the second window (116) lies in a range between 40 µm and 150 µm, in particular in a range between 45 µm and 100 µm. The component carrier (100) according to one of the Claims 1 to 4th wherein the overhang (122) of each of the first electrically conductive layer structure (108) and the second electrically conductive layer structure (110) does not extend over each side wall (124) of the electrically insulating layer structure (102) that defines the through hole (112) is more than 20 µm, in particular not more than 15 µm, more particularly not more than 10 µm. The component carrier (100) according to one of the Claims 1 to 5 , wherein the overhang (122) of the first electrically conductive layer structure (108) is not more than 10 μm beyond at least one, in particular over each, side wall (124). The component carrier (100) according to one of the Claims 1 to 6 comprising electrically conductive filler material (126) which fills at least part of the through hole (112). The component carrier (100) according to Claim 7 , wherein the electrically conductive filler material (126) has a bridge structure (180) which connects opposite side walls (124) of the electrically insulating layer structure (102) delimiting the through hole (112). The component carrier (100) according to Claim 8 , wherein a narrowest vertical thickness (w) of the bridge structure (180) is at least 20 microns. The component carrier (100) according to one of the Claims 1 to 9 , wherein a ratio between the maximum overhang (122) on the first electrically conductive layer structure (108) and the width (120) of the first window (114) is less than 20%. The component carrier (100) according to one of the Claims 1 to 10th , wherein a ratio between the maximum overhang (122) on the second electrically conductive layer structure (110) and the width (118) of the second window (116) is less than 20%. The component carrier (100) according to one of the Claims 1 to 11 wherein at least a portion of the through hole (112) is substantially X-shaped. The component carrier (100) according to one of the Claims 1 to 12th wherein at least a portion of the through hole (112) has a central, substantially cylindrical portion (128) between two opposite, tapered portions (130, 132). The component carrier (100) according to one of the Claims 1 to 13 , wherein the through hole (112) has a lateral offset (134) from the front with respect to the rear of not more than 20 µm, in particular in a range between 15 µm and 20 µm. The component carrier (100) according to one of the Claims 1 to 14 , wherein a laterally narrowest section of the hole (112) is arranged vertically asymmetrically with respect to the front (104) and the rear (106), in particular closer to the front (104) than to the rear (106) or closer to the rear (106 ) than is arranged on the front (104). The component carrier (100) according to one of the Claims 1 to 15 , which has at least one of the following features: the component carrier (100) comprises at least one component which is surface-mounted and / or embedded in the component carrier (100), the at least one component being selected in particular from a group consisting of : an electronic component, an electrically non-conductive and / or electrically conductive insert, a heat transfer unit, a light-conducting element, an energy recovery unit, an active electronic component, a passive electronic component, an electronic chip, a memory device, a filter, an integrated circuit , a signal processing component, a power management component, an opto-electronic interface element, a voltage converter, a cryptographic component, a transmitter and / or receiver, an electromechanical converter, an actuator, a microelectromechanical system, a microprocessor, e a capacitor, a resistor, an inductor, an accumulator, a switch, a camera, an antenna, a magnetic element, a further component carrier and a logic chip; wherein at least one of the electrically conductive layer structures (108, 110) contains at least one from the group consisting of: copper, aluminum, nickel, silver, gold, palladium and tungsten, each of said materials optionally having superconductive material, such as Graphene, coated; wherein the electrically insulating layer structure (102) contains at least one from the group consisting of: resin, in particular reinforced or non-reinforced resin, for example epoxy resin or bismaleimide-triazine resin, FR-4, FR-5, cyanate ester, polyphenylene derivative, Glass, prepreg material, polyimide, polyamide, liquid crystal polymer, build-up film based on epoxy, polytetrafluoroethylene, a ceramic and a metal oxide; the component carrier (100) being shaped as a plate; wherein the device carrier (100) is configured as one of the group consisting of a printed circuit board and a substrate; wherein the component carrier (100) is configured as a laminate type component carrier. A method of manufacturing a component carrier (100), the method comprising: Providing an electrically insulating layer structure (102) with a front side (104) and a back side (106), the front side (104) with a first electrically conductive layer structure (108) and the back side (106) with a second electrically conductive layer structure (110 ) is covered; Performing a first laser drilling through the first electrically conductive layer structure (108) and into the electrically insulating layer structure (102) from the front (104), thereby forming a blind hole (136) in the electrically insulating layer structure (102); thereafter performing a second laser drilling through the second electrically conductive layer structure (110) and through the electrically insulating layer structure (102) from the rear side (106), thereby extending the blind hole (136) into a laser through hole (112); wherein the first laser drilling is performed with a laser beam (138) that has a greater width (148) than another width (150) of another laser beam (140) used for the second laser drilling. Procedure according to Claim 17 , a difference between the widths (148, 150) of the first laser beam (138) performing the first laser drilling and the second laser beam (140) performing the second laser drilling in a range between 5 µm and 50 µm, particularly is in a range between 10 µm and 30 µm. Procedure according to Claim 17 or 18th , the width (148) of the first laser beam (138) being in a range between 50 μm and 200 μm, in particular in a range between 65 μm and 120 μm. Method according to one of the Claims 17 to 19th , The width (150) of the second laser beam (140) in a range between 40 microns and 150 microns, in particular in a range between 45 microns and 100 microns. Method according to one of the Claims 17 to 20 , wherein the first laser drilling is carried out with a lower laser power than the second laser drilling. Method according to one of the Claims 17 to 21 , the first laser drilling with a temporal shorter laser irradiation than the second laser drilling is performed. Method according to one of the Claims 17 to 22 , wherein the first laser drilling comprises a laser shot and the second laser drilling comprises only one laser shot. Method according to one of the Claims 17 to 22 , wherein the first laser drilling comprises one laser shot and the second laser drilling comprises two laser shots. Method according to one of the Claims 17 to 23 , wherein the first laser drilling and the second laser drilling are carried out such that a laterally narrowest section of the through hole (112) is arranged vertically asymmetrically with respect to the front side (104) and the rear side (106). Procedure according to Claim 25 , wherein the first laser drilling is carried out with a lower laser energy than the second laser drilling, so that the laterally narrowest section of the through hole (112) is closer to the front side (104) than to the rear side (106). Procedure according to Claim 25 , wherein the first laser drilling is performed with a first laser shot from the front (104) with a smaller energy and a larger laser diameter than a subsequent second laser shot from the front (104), followed by the second laser drilling from the rear (104) with a Another laser shot that has a smaller laser diameter than that of the first laser shot and larger than that of the second laser shot, so that the laterally narrowest section of the through hole (112) is closer to the rear side (106) than to the front side (104).

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