Manufacturing a trapezoidal through-hole in a component carrier material

Abstract

A method of manufacturing a component carrier (100), the method comprising: Providing an electrically insulating layer structure (102) having a front side (104) and a back side (106), wherein the front side (104) is covered with a first electrically conductive layer structure (108) and the back side (106) is covered with a second electrically conductive layer structure (110); Carrying out a first opening process, in particular a first laser drilling, through the first electrically conductive layer structure (108) and into the electrically insulating layer structure (102) from the front side (104), thereby forming a blind hole (123) in the electrically insulating layer structure (102); then carrying out a second opening process, in particular 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), in order to thereby widen the blind hole (123) to a through-opening (114), in particular a laser through-opening (114), having a substantially trapezoidal shape; wherein the through-opening (114) tapers with a substantially trapezoidal shape from the rear side (106) to the front side (104); wherein the through-opening (114) is completely filled with electrically conductive filling material (118).

Description

Field of the invention

[0001] The invention relates to a method for producing a component carrier and to a component carrier. Technological background

[0002] In the context of growing product functionalities of component carriers equipped with one or more electronic components, and increasing miniaturization of such components as well as a growing number of components to be mounted on component carriers, for example, printed circuit boards, increasingly high-performance array-like components or packages with many components are being used. These have a plurality of contacts or connections with ever smaller spacing between these contacts. The dissipation of heat generated by such components and the component carrier itself during operation is becoming an increasing problem. At the same time, component carriers must be mechanically robust and electrically reliable in order to operate even under harsh conditions. All of these requirements go hand in hand with the progressive miniaturization of component carriers and their components.

[0003] Furthermore, it can be advantageous to efficiently and reliably connect electrically conductive layer structures and / or components embedded in a component carrier. Forming mechanical vias and laser vias that can be filled with copper can be advantageous for these and other purposes. However, it is desirable that the electrical connections in a component carrier be reliable.

[0004] US 8,698,009 B2 discloses a method for manufacturing a printed circuit board. The printed circuit board comprises a substrate 12 through which openings are formed from both sides by means of laser shots. The surfaces 121, 122 of the substrate 12 are coated with copper layers 101, 102. The openings are formed by forming a plurality of interconnected openings H1, H2, and H3 in the substrate 12. The geometry of the resulting opening is trapezoidal in an upper section H2 and semicircular in a lower section H1, H3.

[0005] JP 2018 - 163 986 A discloses an electrode substrate comprising a substrate 12 having a first surface and a second surface, wherein a plurality of through-openings 20 are formed through the substrate 12 from the first surface to the second surface. The geometry of the through-openings 20 is, for example, Fig. 2: a first side wall part 21A tapers from an [upper] first surface 13 towards a [lower] second surface 14. A second side wall part 21B tapers in the opposite direction from the second surface 14 towards the first surface 13. In the middle, the side wall parts are connected to one another so that the through opening has the shape of an hourglass.

[0006] JP 2011-210794 A discloses a method for manufacturing a printed circuit board. The circuit board comprises a laminated board 20 having an insulating substrate 21 and a metal layer 11, 12 on each of two main surfaces of the insulating substrate 21. A through hole 41 is formed in the insulating substrate 21 such that a diameter of the through hole 41 tapers from an upper surface of the insulating substrate 21 to a predetermined depth position and widens from the predetermined depth position toward a lower surface of the insulating substrate 21. Fig. 4 shows an example of a through-hole 40 which tapers continuously through the entire thickness of the insulating substrate 25, wherein the through-hole 40 is not completely filled with electrically conductive material due to this geometry. Summary of the invention

[0007] There may be a need for an electrical connection in a component carrier with high electrical reliability.

[0008] According to the inventive embodiment of the invention, a method for producing a component carrier is provided, the method comprising providing an electrically insulating layer structure having a front side and a back side, wherein the front side is covered with a first electrically conductive layer structure and the back side is covered with a second electrically conductive layer structure; performing a first opening process (in particular a first laser drilling) through the first electrically conductive layer structure and into the electrically insulating layer structure from the front side to thereby form a blind hole in the electrically insulating layer structure;and thereafter performing a second opening process (in particular a second laser drilling) through the second electrically conductive layer structure and through the electrically insulating layer structure from the rear side, in order to thereby widen the blind hole to a through-opening (in particular a laser through-opening) with a substantially trapezoidal shape, wherein the through-opening tapers with a substantially trapezoidal shape from the rear side to the front side and wherein the through-opening is completely filled with electrically conductive filling material.;

[0009] According to an exemplary embodiment of the invention, a component carrier is provided, which comprises an electrically insulating layer structure having a front side and a back side; a first electrically conductive layer structure covering the front side of the electrically insulating layer structure; a second electrically conductive layer structure covering the back side of the electrically insulating layer structure; a through-opening (in particular a laser through-opening) having a substantially trapezoidal shape extending through the first electrically conductive layer structure, the electrically insulating layer structure and the second electrically conductive layer structure, and an electrically conductive filling material filling at least a part of the through-opening (in particular the laser through-opening) (i.e.only fills part of the through-opening while another part remains free of the filler material, or fills the entire through-opening with the filler material), wherein material interfaces are formed in interface regions between the first electrically conductive layer structure and the electrically conductive filler material and between the second electrically conductive layer structure and the electrically conductive filler material.

[0010] In the context of the present application, the term "component carrier" may in particular refer to any support structure suitable for receiving one or more components thereon and / or therein to provide mechanical support and / or electrical connectivity. In other words, a component carrier may be configured as a mechanical and / or electronic carrier for components. In particular, a component carrier may be one of a printed circuit board, an organic interposer, and an IC (integrated circuit) substrate. A component carrier may also be a hybrid board that combines various of the above-mentioned types of component carrier.

[0011] In the context of the present application, the term “layer structure” may in particular refer to a continuous layer, a structured layer or a plurality of non-contiguous islands in a common plane.

[0012] In the context of the present application, the term "laser drilling" can, in particular, refer to the removal of material from an electrically conductive layer structure and / or an electrically insulating layer structure by directing a laser beam onto the respective layer structure. The energy of the laser beam then removes the material from the respective layer structure, thereby forming a corresponding drill hole.

[0013] In the context of the present invention, the term "blind hole" may, in particular, refer to a hole that has a closed bottom. More specifically, a blind hole in the electrically insulating layer structure may refer to a hole that is formed to a certain depth without breaking through to the other side of the electrically insulating layer structure.

[0014] In the context of the present application, the term "through-opening" may in particular refer to a hole having an open bottom. More specifically, a through-opening extending through the electrically insulating layer structure and the electrically conductive layer structures may refer to a hole formed such that it extends completely through the material of the electrically insulating layer structure and the electrically conductive layer structures, and which is in particular and preferably formed by laser processing. Thus, the through-opening may be a laser through-opening. A through-opening may, for example, be produced 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 may be performed from each of these sides.Forming a through hole by laser machining only one main surface is also possible. Furthermore, the formation of a through hole can also be performed by methods other than laser machining, for example, by plasma treatment.

[0015] In the context of the present application, the term "through-opening with a substantially trapezoidal shape" may, in particular, refer to a through-opening that extends through the electrically insulating layer structure and the electrically conductive layer structures and has the shape of a trapezoid in a cross-section perpendicular to the main surfaces of the layer structures. A trapezoid may be defined as a convex quadrilateral with a pair of parallel sides, wherein the remaining two sides may not be parallel to each other. The parallel sides may also be parallel to the layer structures, wherein the non-parallel sides may extend in an inclined manner through the electrically insulating layer structure.In a three-dimensional view, the through-hole (when filled with electrically conductive filler material) may substantially have the shape of a truncated cone (in other words, a frustum of a cone). However, it will be understood by those skilled in the art that a substantially trapezoidal shape may have slight deviations from a strictly trapezoidal shape and, for example, may be shaped as a slightly asymmetric trapezoid. One reason for such a slight deviation may be a slight offset between the laser processing of the front side and the laser processing of the back side of the electrically insulating layer structure. Such an offset may, in turn, be caused by inaccuracies in alignment, etc.

[0016] In the context of the present application, the term "material interface" may in particular refer to an area where the surface of one material structure abuts the surface of another material structure. The abutting materials may be different materials or may be the same material (e.g., copper). However, a copper / copper interface of different copper structures is still visible in a cross-sectional view of the component carrier. For example, one of the copper structures may be a patterned copper foil, while the other copper structure may be plated copper (in particular, formed by electroplating). As is known to those skilled in the art, the formation of plated copper may be further promoted by previously forming a very thin seed layer (e.g., by electroless deposition).Even if such an extremely thin seed layer is present between the two described copper structures - as an example of the material structures having a material interface therebetween - a person skilled in the art will still consider that the two described copper structures (in the example a structured copper foil and copper formed by means of electroplating) have a material interface therebetween.

[0017] According to an exemplary embodiment, a through-opening with a substantially trapezoidal cross-sectional shape is formed in a stack composed of a central electrically insulating layer structure covered with two electrically conductive layer structures on opposite main surfaces. To produce such a through-opening, a window can first be opened in one of the electrically conductive layer structures by means of a first opening process (in particular a first laser beam), which additionally removes only a small part of the material of the electrically insulating layer structure below the window. This first opening process (in particular the first laser treatment) can be followed by a second opening process (in particular a second laser treatment with a second laser beam) from a rear side, which completes the formation of the trapezoidal through-opening.Preferably, the first opening process may be a laser process (but may also be another material removal process), while the second opening process may preferably also be a laser process (but may also be another material removal process).

[0018] A subsequent process for filling the produced vias with an electrically conductive material, for example, coated copper, can be carried out with high efficiency and without the risk of creating large voids in the opening. However, characteristic material interfaces between the electrically conductive layer structures (for example, patterned copper foils) on the one hand and the electrically conductive filling medium (for example, copper formed by electroplating) on ​​the other hand can be the fingerprint of the described process.

[0019] By setting the first laser beam, as a preferred embodiment of the first opening process, with a sufficiently low energy or power to ensure that the first laser shot does not reach the opposing electrically conductive layer structure, unwanted reflection of the laser beam from the opposing electrically conductive layer structure and unwanted melting of the opposing electrically conductive layer structure as a result of the energy exposure of the laser beam can be prevented. By preventing the first laser beam from reaching the opposing electrically conductive layer structure, problems with the reliability of the formed laser through-opening can be reliably avoided.

[0020] In general, exemplary embodiments of the invention may use different laser beams for drilling from the front and back sides in a favorably controlled ratio to prevent laser reflection and / or laser-induced melting beneath the opening in the electrically conductive layer structure (in particular, a copper opening). More generally, exemplary embodiments of the invention may use a material removal technology other than laser irradiation for the first opening process and / or for the second opening process. Particularly preferably, substantially no additional hardware and processing resources are required to carry out the described method.

[0021] An exemplary embodiment of the invention provides a component carrier with a trapezoidal opening in an electrically insulating layer structure in order to obtain a reliable laser via. This can be advantageous in particular for thin cores (i.e. for electrically insulating layer structures which have a thickness of less than 100 µm, in particular less than 60 µm). The manufactured laser via has a trapezoidal shape with a lower width which is greater than the upper width. Such a trapezoidal laser via can be formed in particular by means of a two-stage laser drilling process: First, laser drilling from the front side to form a shallow blind hole. Subsequently, laser drilling from the back side in order to widen the blind hole into a via. Optionally, it is subsequently possible to partially or completely fill the laser via with electrically conductive material.For example, this can be accomplished by means of a two-step metal filling procedure (in particular, by plating). First, a substantially horizontal electrically conductive bridge having two opposing concave surfaces can be formed. This procedure can be followed by filling concave recesses above and below the bridge, for example, in one or more further plating procedures.

[0022] Advantageously, the described manufacturing architecture does not form a bottle hole when the electrically insulating layer structure (particularly when embodied as a thin core) is drilled. Furthermore, an X-shape of the laser via can be avoided, resulting in better stress distribution in the laser via. Furthermore, higher reliability can be achieved because the risk of bottom separation can be reliably avoided. Furthermore, an exemplary embodiment of the invention can provide a simpler and faster laser process than, for example, blind-hole approaches. Furthermore, a filling process for filling the laser via with electrically conductive material can be simpler because, after bridging, the via is represented by a blind hole on the bottom side and a recess on the front side. The reliability of the process for forming such a laser via is high. Detailed description of exemplary embodiments

[0023] Further exemplary embodiments of the method and the component carrier are explained below.

[0024] In one embodiment, the first laser drilling and the second laser drilling can be performed such that the laser through-hole with the substantially trapezoidal shape tapers from the back side to the front side. For example, the taper between the front side and the back side can be continuously conical. The narrowest part of the laser through-hole can be located at the first electrically conductive layer structure.

[0025] In one embodiment, the first laser drilling is performed without a conformal mask on the front side. Correspondingly, the second laser drilling can be performed without a conformal mask on the back side. In particular, the first laser drilling can be performed without previously forming a window in the first electrically conductive layer structure. Accordingly, the second laser drilling can be performed without previously forming a window in the second electrically conductive layer structure. The formation of a mask and a window on / in the respective electrically conductive layer structure before the laser process can be omitted, for example if the outer surface of the respective electrically conductive layer structure has received a surface treatment (for example the formation of black oxide) before the laser process.Such black oxide can suppress the tendency of laser light to be reflected at the outer surface of the respective electrically conductive layer structure. Therefore, the method may preferably comprise forming black oxide on an outer surface of at least one of the first electrically conductive layer structure and the second electrically conductive layer structure before laser drilling through the first electrically conductive layer structure and the second electrically conductive layer structure, respectively. However, any other surface treatment procedure may also be performed, for example, by performing a bond film process or a Z-process. Any pretreatment for a laser process may be used. Alternatively, direct laser drilling of a sufficiently thin electrically conductive layer structure is also possible.For example, direct drilling is possible if the thickness of the respective electrically conductive layer structure is sufficiently thin, for example 2 µm.

[0026] In one embodiment, the first laser drilling may be performed with a narrower laser beam than the second laser drilling. A consequence of such a process may be the trapezoidal shape of the laser through-hole. This may prevent the formation of stress centers, which occur in conventional processes resulting in X-shaped laser through-holes. Regarding the different sizes of the laser beams during front-side drilling and back-side drilling, the effect of a front-to-back offset may be taken into account. If the difference in sizes does not cover the offset, a large overhang may arise on one side, and a defect may appear in the shape, which is then no longer trapezoidal. Therefore, the offset should be kept as small as possible. In one embodiment, the first laser drilling is performed with a lower laser energy than the second laser drilling.A soft and sufficiently low-energy first laser shot from the front side can ensure that the first laser shot does not extend to the second electrically conductive layer structure. This can prevent unwanted heating and a reduction in load capacity. In contrast, a subsequent hard and sufficiently high-energy second laser shot from the back side can ensure that the previously formed shallow blind hole can be expanded to create a through-hole.

[0027] In one embodiment, the first laser drilling is performed to promote heat transfer in the first electrically conductive layer structure in a horizontal direction and to inhibit heat transfer in a vertical direction. This can advantageously limit the vertical expansion of the blind hole after the first laser shot from the front side. As a result, reliability issues can be avoided.

[0028] In particular, the method may comprise promoting heat transfer in the horizontal direction and inhibiting heat transfer in the vertical direction by operating a laser beam during the first laser drilling at an unstable processing point. In the context of the present application, the term "configuring a laser beam to promote heat transfer in the horizontal direction and inhibit heat transfer in the vertical direction" may in particular mean that at least one parameter characterizing the laser beam, in particular its energy and / or its operating point, is adjusted such that the heat of the laser energy propagates to a greater or substantial extent in a horizontal direction along the extent of the electrically conductive layer structure than vertically into the material of the electrically insulating layer structure below.Thus, only a small or marginal fraction of the laser energy can propagate vertically. A very suitable design parameter for increasing horizontal heat transfer while simultaneously reducing vertical heat transfer is adjusting the energy of the first laser beam, as described in more detail below with reference to . Fig. 2 and Fig. 3 is described.

[0029] In one embodiment, at least one of the first laser drilling and the second laser drilling comprises only a single laser shot. Alternatively, at least one of the first laser drilling and the second laser drilling comprises a plurality of laser shots.

[0030] In one embodiment, the method comprises at least partially filling the laser through-hole with an electrically conductive filler material, preferably copper. For example, filling the laser through-hole with the electrically conductive filler material first comprises forming a seed layer, for example, by electroless plating, followed by depositing additional electrically conductive material, for example, by electroplating.

[0031] In one embodiment, filling the laser through-opening with the electrically conductive filling material comprises forming lining structures that coat inclined sidewalls of the substantially trapezoidal laser through-opening with electrically conductive filling material that connects to the first electrically conductive layer structure and the second electrically conductive layer structure. Accordingly, the electrically conductive filling material of the laser through-opening of the component carrier may comprise lining structures that coat inclined sidewalls of the substantially trapezoidal laser through-opening with electrically conductive filling material that connects to the first electrically conductive layer structure and the second electrically conductive layer structure.The trapezoidal shape of the laser via is perfectly compatible with the formation of coating structures, without unwanted voids inside. This can ensure high electrical reliability of the copper-filled laser via.

[0032] In one embodiment, filling the laser through-hole with electrically conductive material comprises forming a substantially horizontal bridge structure connecting the coating structures on the inclined sidewalls. Accordingly, the electrically conductive fill material of the laser through-hole of the component carrier may comprise a substantially horizontal bridge structure connecting the coating structures on the inclined sidewalls. The tapered configuration of the coating structures may, upon continuation of a coating process, result in the formation of a bridge structure laterally connecting opposing coating structures in a vertical plane in which the distance between the coating structures is relatively small. This may promote the formation of a cantilevered bridge structure with high reliability.In particular, a freely hanging, asymmetric bridge structure can be achieved, which is located outside a vertical center of the passage opening.

[0033] In one embodiment, filling the laser via with electrically conductive material comprises at least partially filling remaining gaps above and / or below the bridge structure and laterally between the coating structures with further electrically conductive filler material. After the coating structures and the bridge structure have formed a substantially H-shaped structure (but with inclined long legs of the H), continuing a copper plating procedure can reliably fill the remaining gaps above and below the bridge structure and laterally between opposing coating structures.

[0034] In another embodiment, the method comprises performing a first opening process as a plasma process or as a patterning of a photo-patternable dielectric. Thus, the first opening process can also be performed using a plasma or PID process as an alternative to a laser process.

[0035] In one embodiment, at least one of the material interfaces between the electrically conductive fill structure and the respective one of the electrically conductive layer structures may be substantially beak-shaped. In the context of the present application, the term “beak-shaped” may in particular refer to a structure shaped similarly to a triangle or a “V.” It may have a shape similar to the beak of a bird. In particular, the narrow tips of the beak-shaped material interfaces may be oriented inwards, while the wider sections of the beak-shaped material interfaces may be oriented outwards (see Fig. 6). A substantially beak-shaped material interface may, in particular, be substantially V-shaped or substantially U-shaped. Such a shape may be promoted by an overhang from one or both ends of one or both of the electrically conductive layer structures after forming a window by laser drilling.

[0036] In one embodiment, the material interfaces between the electrically conductive fill structure and the respective electrically conductive layer structures are arranged at or near corners of the electrically insulating layer structure between the electrically conductive fill structure, on the one hand, and a respective one of the first electrically conductive layer structure and the second electrically conductive layer structure, on the other hand. However, they can be shifted inwardly or outwardly in the plane of the respective electrically conductive layer structure, depending on certain manufacturing factors (for example, depending on an overhang of a respective electrically conductive layer structure beyond the electrically insulating layer structure next to the laser through-opening and / or depending on a lateral offset between the front-side laser beam and the back-side laser beam).

[0037] In one embodiment, the material interfaces are copper / copper interfaces. In particular, copper material provided by a copper foil and copper material provided by coating (in particular by electroless plating and / or electroplating) can be clearly distinguished when experimentally analyzing a cross-section of a component carrier. Even sections of the electrically conductive fill structure formed at different coating stages can be distinguished when experimentally analyzing a cross-section of a component carrier.

[0038] In one embodiment, the electrically conductive fill material of the laser via opening comprises gap-filling structures. These may include a first gap-filling structure that at least partially fills a remaining gap above the bridge structure and / or a second gap-filling structure that at least partially fills a remaining gap below the bridge structure. In other words, the corresponding gap may be completely filled with electrically conductive material. In such a scenario, an upper surface of the electrically conductive fill structure may be planar and aligned with an upper surface of the first electrically conductive layer structure. Accordingly, a lower surface of the electrically conductive fill structure may be planar and aligned with a lower surface of the second electrically conductive layer structure.However, it is also possible that the respective gap is only partially filled with metallic material of the electrically conductive fill structure. In such a scenario, a recess may remain on an upper surface and / or a lower surface of the electrically conductive fill structure.

[0039] The upper gap may be defined at a bottom side by an upper concave surface of the bridge structure. The lower gap may be defined at a top side by a lower concave surface of the bridge structure. Thus, a surface of the bridge structure on the front side may be concave. It is also possible for a surface of the bridge structure on the back side to be concave. Given the trapezoidal shape and the corresponding tapered geometry, the concave surface of the bridge structure on the back side may have a greater curvature than the concave surface of the bridge structure on the front side.

[0040] In one embodiment, the component carrier has at least one further material interface between the coating structures and at least one of the gap-filling structures and / or between the bridge structure and at least one of the gap-filling structures. Since the coating structures, the bridge structure, and the gap-filling structures can be produced in different, successive coating stages, they can be differentiated by experimentally analyzing a cross-section of the component carrier.

[0041] In one embodiment, a lateral outer surface of the electrically conductive filler material has an inclined, substantially straight shape. The sidewall of the electrically conductive filler material can therefore be free of edges and narrow points that traditionally represent stress zones. Consequently, the reliability of the component carrier can be improved.

[0042] In one embodiment, a smallest outer diameter of the electrically conductive fill material is arranged on the front side. From this front side, the diameter of the electrically conductive fill material can continuously increase to the back side. This geometry can suppress the tendency to form undesirable material-free voids in an interior of the electrically conductive fill structure (such as can occur in a laser via with an X-shape).

[0043] In one embodiment, the vertical thickness of the electrically insulating layer structure is less than 110 µm, in particular less than 60 µm. Thus, the described method is particularly advantageous for forming laser through-holes in relatively thin cores.

[0044] In one embodiment, a ratio between a smaller side length of the trapezoid on the first electrically conductive layer structure and a larger side length of the trapezoid on the second electrically conductive layer structure can be in a range between 0.6 and 0.8. The two sides with smaller and larger side lengths can be parallel to each other. In particular, if the specified value is 0.6 or larger, this can reliably prevent excessive overhang and lead to suitable reliability. To avoid defects such as residues and overhang, the specified value should not be too high; for example, it can be up to 0.8.

[0045] In one embodiment, the component carrier comprises a stack of at least one electrically insulating layer structure and at least two electrically conductive layer structures. For example, the component carrier can be a laminate of said electrically insulating layer structure(s) and the electrically conductive layer structure(s), in particular formed by applying mechanical pressure and / or thermal energy. Said stack can provide a plate-shaped component carrier which is suitable for providing a large mounting surface for further components and which is nevertheless very thin and compact. The term "layer structure" can in particular refer to a contiguous layer, a structured layer, or a plurality of non-contiguous islands in a common plane.

[0046] In one embodiment, the component carrier is plate-shaped. This contributes to the compact design, while the component carrier still provides a large base for mounting components. Furthermore, a bare chip, in particular, as an example of an embedded electronic component, can be easily embedded into a thin plate, such as a printed circuit board, due to its small thickness.

[0047] 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).

[0048] In the context of the present application, the term “printed circuit board” (PCB) may in particular refer to a component carrier (which may be plate-shaped (i.e. planar), three-dimensionally curved (e.g. when manufactured using 3D printing), or which may have any other shape) formed by laminating a plurality of electrically conductive layer structures with a plurality of electrically insulating layer structures, for example by applying pressure, if desired accompanied by the supply of thermal energy. Preferred materials for PCB technology are the electrically conductive layer structures made of copper, whereas the electrically insulating layer structures may comprise resin and / or glass fibers, so-called prepreg or FR4 material.The various electrically conductive layer structures can be connected to each other in a desired manner by forming through-holes through the laminate, for example, by laser drilling or mechanical drilling, and by filling them with electrically conductive material (especially copper), thereby forming vias as through-hole connections. Besides one or more components, which may be embedded in a printed circuit board, a printed circuit board is typically configured to receive one or more components on one or both opposite surfaces of the plate-shaped printed circuit board. These may be connected to the respective main surface by soldering. A dielectric part of a PCB may be composed of resin with reinforcing fibers (for example, glass fibers).

[0049] In the context of the present application, the term "substrate" may, in particular, refer to a small component carrier having substantially the same size as a component (in particular an electronic component) to be mounted thereon. In particular, a substrate may be understood as a carrier for electrical connections or electrical networks, as well as a component carrier comparable to a printed circuit board (PCB), but with a considerably higher density of lateral and / or vertically arranged connections. Lateral connections are, for example, conductive paths, whereas vertical connections may, for example, be drilled holes.These lateral and / or vertical connections are arranged in the substrate and can be used to provide electrical and / or mechanical connections of packaged components or unpackaged components (e.g., bare chips), particularly IC chips, to a printed circuit board or an intermediate printed circuit board. Thus, the term "substrate" also includes "IC substrates." A dielectric portion of a substrate can be constructed of resin with reinforcing particles (e.g., reinforcing beads, particularly glass beads).

[0050] A substrate or interposer may comprise or consist of at least one layer of glass, silicon, ceramic, and / or organic material (e.g., resin). A substrate or interposer may also comprise a photo-patternable or dry-etchable organic material, for example, epoxy-based build-up films or polymer compounds such as polyimide, polybenzoxazole, or benzocyclobutene.

[0051] In one embodiment, the at least one electrically insulating layer structure comprises at least one from the group consisting of resin (e.g., reinforced or non-reinforced resin, e.g., epoxy resin or bismaleimide-triazine resin, in particular FR-4 or FR-5), cyanate ester, polyphenylene derivative, glass (in particular, glass fibers, glass beads, multilayer glass, glass-like materials), prepreg material, photoimageable dielectric material, polyimide, polyamide, liquid crystalline polymer (LCP), epoxy-based build-up film, polytetrafluoroethylene (Teflon), a ceramic, and a metal oxide. Reinforcing materials, e.g., meshes, fibers, or beads, e.g., made of glass (multilayer glass), may also be used. Although prepreg, FR4, or epoxy-based build-up film or photoimageable dielectrics are typically preferred, other materials may also be used.For high frequency applications, high frequency materials such as polytetrafluoroethylene, liquid crystalline polymer and / or cyanate ester resins can be implemented in the component carrier as an electrically insulating layer structure.

[0052] In one embodiment, the at least one electrically conductive layer structure comprises at least one material selected from the group consisting of copper, aluminum, nickel, silver, gold, palladium, and tungsten. Although copper is typically preferred, other materials or coated versions thereof are also possible, in particular coated with a superconducting material such as graphene.

[0053] It is also possible to provide the component carrier with at least one surface-mounted and / or embedded component. The at least one component can be selected from a group consisting of an electrically non-conductive inlay, an electrically conductive inlay (e.g., a metal inlay, preferably comprising copper or aluminum), a heat transfer unit (e.g., a heating tube), a light-conducting element (e.g., an optical waveguide or a light guide connection), an electronic component, or combinations thereof.For example, the component may be an active electronic component, a passive electronic component, an electronic chip, a memory device (e.g., a DRAM or other data storage device), a filter, an integrated circuit, a signal processing component, a power management component, an optoelectronic interface element, a voltage converter (e.g., a DC / DC converter or an AC / DC converter), a cryptographic component, a transmitter and / or receiver, an electromechanical transducer, 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 an energy harvesting unit. However, other components may be embedded in the component carrier. For example, a magnetic element may be used as a component.Such a magnetic element may be a permanent magnetic element (e.g., a ferromagnetic element, an antiferromagnetic element, a multiferroic element, or a ferrimagnetic element, e.g., a ferrite core) or may be a paramagnetic element. However, the component may also be another component carrier (e.g., a printed circuit board, a substrate, or an interposer) in a board-in-board configuration. The component may be surface-mounted on the component carrier and / or may be embedded in an interior thereof. Furthermore, other components, in particular those that generate and emit electromagnetic radiation and / or are sensitive to electromagnetic radiation propagated from an environment, may also be used as a component.

[0054] In one embodiment, the component carrier is a laminate-type component carrier. In such an embodiment, the component carrier is a composite of multiple layer structures that are stacked and bonded together by applying a contact force and / or heat.

[0055] The above-defined aspects and further aspects of the invention will become apparent from the examples of embodiments which will be described below and explained with reference to these examples of embodiments. Fig. 1 and Fig. 4 to Fig. 6 show cross-sectional views of structures obtained during the execution of a method for manufacturing a component carrier with a laser through-hole, as in Fig. 6, by means of a double laser shot treatment from opposite sides according to an exemplary embodiment of the invention. Fig. 2 shows a diagram showing a dependence between the energy of a laser beam and an opening diameter of a window in an electrically conductive layer structure in an operating mode with a stable processing point. Fig. 3 shows a diagram showing a dependency between the energy of a laser beam and an opening diameter of a window in an electrically conductive layer structure in an operation mode according to an exemplary embodiment of the invention with an unstable processing point.

[0056] The representations in the drawings are schematic. Similar or identical elements are designated by the same reference numerals in different drawings.

[0057] Before exemplary embodiments are described in more detail with reference to the drawings, some basic considerations should be summarized on the basis of which exemplary embodiments of the invention were developed.

[0058] A common drawback in laser via formation is bottlenecks, which can occur particularly when a thin core (especially with a thickness of less than 110 µm, more particularly less than 60 µm) is used as the electrically insulating layer structure to be laser drilled. The heat from a first laser shot on the front side, which passes through an electrically conductive layer structure of the front side and into the electrically insulating layer structure, can induce damage to the electrically conductive layer structure (especially a lower copper foil) of the back side. Such a damaged area cannot be drilled with high accuracy on the bottom side, resulting in a major reliability risk.

[0059] A key idea of ​​an exemplary embodiment of the invention is to make a laser via formation process reliable, in particular with regard to forming a laser via opening with a thickness of less than 110 µm, in particular less than 60 µm. In fact, when forming a conventional X-shaped laser via opening with a CO 2 Lasers in a thin core carry a high risk of bottle holes induced by the first shot (or multiple shots) from the front surface, which can undesirably extend to the lower copper. Such a bottle hole can modify the structure and prevent precise drilling of the other side. Such bottle holes can pose a critical reliability issue. Undesired bottle hole formation can lead to separation, inclusions, cracks, or other electrical defects.

[0060] To avoid at least some of the aforementioned and / or other deficiencies, an exemplary embodiment of the invention forms the upper opening, which extends through the upper electrically conductive layer structure and a portion of the electrically insulating layer structure, with a soft (in terms of energy exposure) laser shot. Very advantageously, an intentionally unstable laser shot can be adjusted so that the laser energy tends to open more of the copper of the upper electrically conductive layer structure on the front side rather than scattering to the underside and damaging the copper of the lower electrically conductive layer structure.Subsequently, one or more consecutive laser shots can be applied to the lower side in such a way that any remaining dielectric material (particularly resin and glass) of the electrically insulating layer structure is removed and a stable and well-defined opening in the form of the trapezoidal laser via is provided. Thus, an exemplary embodiment of the invention can avoid a conventional X-shape, which can be undesirable, especially for thin cores, since the X-shape can induce a higher stress concentration in the neck of the laser via and therefore represents a mechanical weakness that can reduce the reliability of the vias.

[0061] Additionally, according to an exemplary embodiment of the invention, filling such a via in thin cores eliminates the need for a special bridge plating process. In fact, a copper electroplating process with properly controlled parameters may be sufficient to close the top opening and fill the remainder or part of the via.

[0062] In a preferred embodiment, the trapezoidal laser through-hole may have a shape characterized by a ratio between the upper and lower diameters of at least 0.7, preferably at least 0.8, in order to reliably avoid bottlenecks. Advantageously, the trapezoidal laser through-hole may have a continuous taper between the upper end and the lower end, i.e., it may not have an X-shape. This may contribute to avoiding a stress concentration in the bottleneck of the X-shape, which can conventionally lead to a high glass protrusion. With regard to a coating procedure for filling the laser through-hole, it may be advantageous to fill the upper side first to create a blind hole. Advantageously, the first laser shot(s) may be designed as a soft (i.e.,not extending to the opposite second electrically conductive layer structure) in order to avoid bottlenecks.

[0063] By forming a trapezoidal through-hole instead of an X-shaped through-hole according to an exemplary embodiment of the invention, a smaller diameter on one side and a taper from top to bottom can be achieved. This can improve the quality of the laser through-hole, as undesirable bottlenecks can be avoided and better reliability can be achieved. Furthermore, simple and rapid filling of the trapezoidal laser through-hole can be possible.

[0064] The following figure description shows an example of forming a laser through-hole by laser drilling through a thin core.

[0065] Fig. 1 shows a cross-sectional view of a structure formed during the execution of a method for manufacturing a component carrier 100 with a laser via using a double laser shot treatment according to an exemplary embodiment of the invention.

[0066] Before the laser process begins, an electrically insulating layer structure 102 is provided, which has a front side 104 and a back side 106. For example, the electrically insulating layer structure 102 can be made of fully cured dielectric material (for example, a fully cured resin such as an epoxy resin with reinforcing particles, for example, glass fibers or glass beads). For example, the electrically insulating layer structure 102 can be embodied as a (particularly relatively thin) core made of prepreg or FR4 material. A vertical thickness, D, of the electrically insulating layer structure 102 can be, for example, 80 µm.

[0067] As in Fig. 1, the front side 104 of the electrically insulating layer structure 102 is covered with a first electrically conductive layer structure 108. The first electrically conductive layer structure 108 can be, for example, a metal layer, for example, a copper foil. Accordingly, the back side 106 of the electrically insulating layer structure 102 is covered with a second electrically conductive layer structure 110. The second electrically conductive layer structure 110 can be, for example, a metal layer, for example, a copper foil.

[0068] To make subsequent laser processing of the electrically conductive layer structures 108, 110 more efficient, the respective outer main surface of the layer structures 108, 110 can be provided with an outer black oxide layer (not shown) prior to laser drilling. The black oxide can suppress the reflection of a laser beam at the respective layer structure 108, 110 and can therefore enable direct removal of the copper material of the respective layer structure 108, 110 without forming a window in the respective layer structure 108, 110 prior to laser processing. Thus, the first laser drilling can be performed without a conformal mask on the front side 104.

[0069] Consequently, a first laser drilling procedure can be carried out by directing a first laser beam (schematically indicated by an arrow 111) from the front side 104 directly through the first electrically conductive layer structure 108 and into the electrically insulating layer structure 102, thereby forming a window 113 in the first electrically conductive layer structure 108 and a blind hole 112 in the electrically insulating layer structure 102.

[0070] The energy of the first laser beam may be so low that only a shallow blind hole 112 is formed in the electrically insulating layer structure 102 to prevent the first laser beam from reaching the second electrically conductive layer structure 110. As will be described in more detail below with reference to Fig. 2 and Fig. 3, the first laser drilling may be performed to promote heat transfer in the first electrically conductive layer structure 108 in a horizontal direction and to inhibit heat transfer in a vertical direction. This may be accomplished by operating the first laser beam during the first laser drilling at an unstable processing point, see reference numeral 222 in Fig. 3. Drilling the front side can be clearly seen according to Fig. 1 use an unstable laser shot.

[0071] The first laser drilling procedure, which Fig. 1 can be carried out using only a single laser shot or using a sequence of multiple laser shots. For the laser method described, it is possible, for example, to use a CO 2 Laser, an excimer laser or a UV laser.

[0072] As a result of the procedure under Fig. 1, a through hole extending only through the first electrically conductive layer structure 108 and the connected blind hole 112 extending only through an upper portion of the electrically insulating layer structure 102 can be opened. During this process, glass and resin of the electrically insulating layer structure 102 are removed while simultaneously forming a taper and avoiding an X-shape.

[0073] How Fig. 1, after the first laser shot, a slight overhang 115 of the first electrically conductive layer structure 108 may remain laterally beyond the electrically insulating layer structure 102. In other words, the lateral width of the window 113 may be slightly smaller than the maximum lateral width of the blind hole 112. However, due to the described method with a soft laser shot, preferably in an unstable operating state, the size of the overhang 115 can be kept very small.

[0074] Fig. 2 shows a diagram 200 illustrating a relationship between the energy (plotted along an abscissa 202) of a laser beam and an opening diameter (plotted along an ordinate 204) or size of the window 113 in an operating mode with a stable processing point 210. This relationship is indicated by a curve 208.

[0075] Curve 208 of diagram 200 shows that as the energy increases, the size or opening diameter of window 113 also increases. In a low-energy range, curve 208 increases with a significant slope. Above a certain energy level, the described dependence no longer applies: in contrast, at higher energy levels, curve 208 approaches a plateau or asymptote, which is defined as the target opening 206 in Fig. 2 is indicated.

[0076] In this range, a further increase in laser energy does not lead to a significant further increase in the opening diameter of the window 113. Clearly, the additional energy in this system leads to significant burning of the resin material of the electrically insulating layer structure 102.

[0077] During the opening of the copper (more generally during the opening of the window 113 in the first electrically conductive layer structure 108 by means of a first laser beam), the laser energy is high and when processing in the stable zone around the stable processing point 210 (maximum copper opening for a given opening or mask), the heat is dissipated into the depths of the via to remove more resin and reach the bottom or onto the wall of the via to remove and burn more resin and subsequently create a pronounced overhang 115 since the copper opening does not get larger.In the context of the present application, the term "overhang" can, in particular, refer to a length of the electrically conductive layer structure directly adjacent to the window, over which length the respective part of the electrically conductive layer structure hangs freely, in the manner of a cantilever, spaced apart with respect to the electrically insulating layer structure and not supported from below by material of the electrically insulating layer structure along the extent of the overhang. As far as the above statement that overhanging material is locally unsupported is concerned, it should be noted that the overhang refers to the substantially resin-free area beneath the respective electrically conductive layer structure. However, it will be understood by those skilled in the art that some residual resin may be present in a gap relating to the overhang.To quantify or measure the overhang value, the length of the substantially resin-free (where resin refers to the electrically insulating layer structure) undercut directly beneath an overhanging electrically conductive layer structure can be measured (especially even if it is not the most recessed point or total relief beneath the overhanging electrically conductive layer structure, e.g., the copper layer). In other words, to measure the overhang, the undercut can be measured directly beneath the electrically conductive layer structure.

[0078] In an exemplary embodiment, the overhang may be slightly asymmetric due to the described method and also due to the effect of the front-to-back offset.

[0079] It can therefore Fig. 2 it can be concluded that the mere increase of the laser energy does not allow to achieve the desired result of a reduced overhang 115.

[0080] Fig. 3 shows a further diagram 220 showing a dependence between the energy (again plotted along the abscissa 202) of the first laser beam according to Fig. 1 and the aperture diameter (again plotted along the ordinate 204) or size of the window 113 in an operating mode according to an exemplary embodiment of the invention with an unstable processing point 222. Clearly, in an exemplary embodiment of the invention, it is not intended to adjust the energy of the first laser beam such that the laser operates at the stable processing point 210 as close as possible to the maximum opening for the given aperture or mask. In contrast, an exemplary embodiment of the invention operates the laser and adjusts the laser energy accordingly to operate the first laser beam at the unstable processing point 222.

[0081] By opening the window 113 by means of the first laser beam set at the unstable processing point 222, it is very advantageously possible to promote horizontal heat dissipation by providing more space for opening the window 113 in the copper material of the first electrically conductive layer structure 108, instead of drilling a deeper via.

[0082] At the above-mentioned unstable processing point 222, the provided laser beam energy can be largely used and focused on opening the window 113 in the first electrically conductive layer structure 108, creating a larger via while only removing a portion of the dielectric material of the electrically insulating layer structure 102. In this case, the overhang 115 can advantageously be smaller. As a result, there is no risk of bottlenecks during the formation of the laser via opening.

[0083] In view of the above, a preferred embodiment of the invention forms the window 113 in the first electrically conductive layer structure 108 and removes material of the electrically insulating layer structure 102 below the window 113 by means of the first laser beam, which is configured to promote heat transfer in the first electrically conductive layer structure 108 in the horizontal direction and to inhibit heat transfer in the vertical direction (which would only remove more material of the electrically insulating layer structure 102).In particular, the method may include promoting heat transfer in the horizontal direction and inhibiting heat transfer in the vertical direction by adjusting the energy impact of the first laser beam on the first electrically conductive layer structure 108 and the electrically insulating layer structure 102 in accordance with the unstable processing point 222.

[0084] In a particularly preferred embodiment and again referring to Fig. 3, the method comprises adjusting the energy of the first laser beam such that the size L of the window 113 (see target window diameter 224) is achieved which is sufficiently smaller than a maximum opening size A for a given recess.

[0085] The size L of the window 113 corresponds to the unstable processing point 222, whereas the maximum opening size A essentially corresponds to a stable processing point 210, which is Fig. 2. In such a scenario, a particularly small overhang 115 can be achieved.

[0086] Fig. 4 shows a cross-sectional view of a structure produced when carrying out the method for manufacturing the component carrier 100 with the laser via by means of the double laser shot treatment according to the presently described exemplary embodiment of the invention. In particular, Fig. 4 the result of the second laser drilling stage, which is the first laser drilling stage Fig. 1 follows.

[0087] The second laser drilling is also performed without a conformal mask on the backside 106 and without prior formation of a window in the second electrically conductive layer structure 110. Preferably, after black oxide has been formed on an outer surface of the second electrically conductive layer structure 110, the second laser drilling procedure can be performed from the backside 106.

[0088] Thus, from the rear side 106, a second laser beam, as indicated by an arrow 119, can be directed onto and propagated through the second electrically conductive layer structure 110 and subsequently through the electrically insulating layer structure 102. The second laser beam is configured such that the previously formed blind hole 112 is expanded to be converted into a laser through-opening 114 having a substantially trapezoidal shape, as in Fig. 4. The second laser drilling is performed such that the laser through hole 114 tapers with a substantially trapezoidal shape from the back side 106 to the front side 104.

[0089] To obtain the trapezoidal shape, which is shown in the cross-sectional view of Fig. 4 (corresponding to a frustoconical shape in three dimensions), the first laser drilling is performed with a spatially laterally narrower laser beam than the second laser drilling. The backside drilling can be performed with a larger laser beam diameter than the frontside drilling. Furthermore, the softer first laser drilling is performed with a lower laser energy than the harder second laser drilling. The described second laser drilling can be performed using only a single laser shot or a plurality of consecutive laser shots.

[0090] Further referring to Fig. 4, a ratio between a smaller side length, D1, of the trapezoid at the first electrically conductive layer structure 108 and a larger side length, D2, of the trapezoid at the second electrically conductive layer structure 110 may be, for example, 0.7. This design rule has proven very advantageous for preventing excessive overhang. Consequently, a high degree of reliability of the formed laser via opening and, consequently, a high degree of electrical reliability of the component carrier 100 obtained after filling the laser via opening with copper material can be achieved.

[0091] Preferably, a lateral offset between the center of the first laser beam irradiating the front side 104 and the center of the second laser beam irradiating the back side 106 should be small. Preferably, this offset can be set to be less than 15 µm in order to avoid a large overhang (see reference numeral 115 in Fig. 1) on the top. Fig. 5 shows a small offset 115 only on the front side 104, i.e., the side of the first electrically conductive layer structure 108. However, a small offset may also occur on the back side 106, i.e., the side of the second electrically conductive layer structure 110.

[0092] Fig. 5 shows a cross-sectional view of a structure produced during the execution of the method for manufacturing the component carrier 100 with the laser via by means of the double laser shot treatment according to an exemplary embodiment of the invention. A copper plating was carried out according to Fig. 5 already partially implemented.

[0093] More precisely, Fig. 5 shows the result of a first partial filling of the laser via opening 114 with electrically conductive material, for example, copper. Although not shown in the figures, filling the laser via opening 114 with electrically conductive fill material 118 may first comprise forming a very thin seed layer of copper by means of electroless plating. This seed layer may then be used to apply an electrical current for subsequent electroplating of additional electrically conductive material. It is possible for the seed layer to have a thickness greater than 1 µm and / or for multiple cumulative seed layers to be provided. For example, a thickness of one seed layer or a cumulative thickness of a plurality of seed layers may be in a range between 0.5 µm and 5 µm.If multiple seed layers are provided, these may comprise an organic (e.g., polymer) layer, a palladium layer, and / or a copper layer.

[0094] As in Fig. 5 and preferably after the above-mentioned seed layer has been formed, the procedure may then comprise filling the laser through-hole 114 with coating structures 116 of the electrically conductive fill material 118, which coats inclined sidewalls of the substantially trapezoidal laser through-hole 114 with copper or another suitable electrically conductive material. As in Fig. 5, the coating structures 116 are connected to the first electrically conductive layer structure 108 and the second electrically conductive layer structure 110.

[0095] Furthermore, filling the laser through-hole 114 with the electrically conductive filler material 118 by means of copper plating includes forming a substantially horizontal bridge structure 120 that connects the coating structures 116 on the inclined sidewalls. Given the substantially trapezoidal shape of the laser through-hole 114, a vertical center of the bridge structure 120 is arranged closer to the first electrically conductive layer structure 108 than to the second electrically conductive layer structure 110. Thus, bridging the coating structures 116 by means of the bridge structure 120 can form a vertically upwardly displaced neck. Thus, Fig. 5 a freely suspended, asymmetric bridge structure 120 which is arranged outside a vertical center of the through opening 114.

[0096] As also from Fig. 5, an upper surface of the bridge structure 120 is concave and thus forms a depression 121 on the front side 104, i.e., on the side facing the first electrically conductive layer structure 108. The lower surface of the bridge structure 120 is also concave. Thus, the described coating procedure also forms a blind hole 123 (which may also be referred to as a further depression) on the underside of the bridge structure 120, i.e., on the side facing the second electrically conductive layer structure 110. As Fig. 5, the concave surface of the bridge structure 120 on the back side 106 has a greater curvature than the concave surface of the bridge structure 120 on the front side 104. In addition, a lateral outer surface of the electrically conductive filler material 118 has an inclined, substantially straight shape.

[0097] Fig. 6 shows a cross-sectional view of the manufactured component carrier 100 with the laser via according to an embodiment of the invention.

[0098] Fig. Figure 6 shows the final result of the coating process of the described embodiment of the invention, in which the laser through hole 114 was completely filled with electrically conductive filler material 118 (copper in the described embodiment). However, it should be noted that as an alternative to the representation of Fig. 6 may also be possible to fill remaining gaps 122 of the structure according to Fig. 5 only partially filled with electrically conductive filler material 118. For example, an unfilled recess may remain on one or both sides of the bridge structure 120, for example in the form of dips in the electrically conductive filler material 118 at the vertical height of one or both of the electrically conductive layer structures 108, 110.

[0099] In particular, the filling of the laser through hole 114 with the electrically conductive filler material 118 may be continued to fill the remaining gaps 122 above and below the bridge structure 120 with further electrically conductive filler material 118. In other words, the recess 121 and the blind hole 123 may also be filled with copper by continued plating.

[0100] For example, the described filling process can result in the same shape as a blind hole, but with two copper foil openings.

[0101] As a result of the described manufacturing method, the component carrier 100 can be manufactured according to Fig. 6. For example, the component carrier 100 may be a laminate-like plate-shaped printed circuit board (PCB).

[0102] In particular, and as a result or fingerprint of the described manufacturing method, beak-shaped material interfaces 124 are formed in interface regions between the first electrically conductive layer structure 108 and the electrically conductive filler material 118 and between the second electrically conductive layer structure 110 and the electrically conductive filler material 118. The material interfaces 124 are in Fig. 6 with dotted or dashed lines. For example, the beak-shaped material interfaces 124 may have a substantially V-shape or a U-shape when viewed in cross-sectional view of an actually manufactured component carrier 100 of the type shown in Fig. 6. In the embodiment shown, the beak-shaped material interfaces 124 are arranged directly adjacent to corners 127 of the electrically insulating layer structure 102, between the electrically conductive fill structure 118 on the one hand and a respective one of the first electrically conductive layer structure 108 and the second electrically conductive layer structure 110 on the other. Although the material interfaces 124 are copper / copper interfaces, it is clear to those skilled in the art that the material interfaces 124 are visible when a cross-section of a component carrier 100 is analyzed experimentally. Copper foils constituting the electrically conductive layer structures 108, 110 can be clearly distinguished by experimental analysis from electroplated copper constituting the electrically conductive fill material 118.

[0103] Accordingly, further material interfaces 126, 128 between the coating structures 116 and the gap-filling structures 130, 132 and between the bridge structure 120 and the gap-filling structures 130, 132 can be clearly detected by means of routine experimental analysis. A first gap-filling structure 130, which fills a remaining gap (see depression 121) above the bridge structure 120, and a second gap-filling structure 132, which fills a remaining gap (see further depression or blind hole 123) below the bridge structure 120, are shown in Fig. 6 shown.

[0104] As also in Fig. 6, a smallest outer diameter, d, of the electrically conductive filler material 118 is arranged on the front side 104.

[0105] It should be noted that the shape and position of the first material interfaces 124 may depend on the precise processing. For example, the beak-shaped first material interfaces 124 may be shifted inward if a larger value of the overhang 115 is present. The first material interfaces 124 may also be shifted laterally if a larger offset is present, as explained above. It is also possible that the concavity at the further material interfaces 126, 128 may be different from the illustration. Fig. 6 may vary if the exact procedure is different.

[0106] It should be noted that the term "comprising" does not exclude other elements or steps, and "a" or "an" does not exclude pluralities. Elements described in connection with various embodiments may also be combined.

[0107] It should also be noted that reference signs in the claims are not to be construed as limiting the scope of protection of the claims.

[0108] The implementation of the invention is not limited to the preferred embodiments shown in the figures and described above. Instead, a multitude of variants are possible that utilize the solutions shown and the inventive principle, even in the case of fundamentally different embodiments.

Claims

[1] A method of manufacturing a component carrier (100), the method comprising: Providing an electrically insulating layer structure (102) having a front side (104) and a back side (106), wherein the front side (104) is covered with a first electrically conductive layer structure (108) and the back side (106) is covered with a second electrically conductive layer structure (110); Carrying out a first opening process, in particular a first laser drilling, through the first electrically conductive layer structure (108) and into the electrically insulating layer structure (102) from the front side (104), thereby forming a blind hole (123) in the electrically insulating layer structure (102); then carrying out a second opening process, in particular 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), in order to thereby widen the blind hole (123) to a through-opening (114), in particular a laser through-opening (114), having a substantially trapezoidal shape; wherein the through-opening (114) tapers with a substantially trapezoidal shape from the rear side (106) to the front side (104); wherein the through-opening (114) is completely filled with electrically conductive filling material (118). [2] The method according to claim 1, comprising at least one of the following features: wherein the first laser drilling and the second laser drilling are carried out such that the through-hole (114) with the substantially trapezoidal shape tapers from the rear side (106) towards the front side (104); wherein the first laser drilling is performed without a conformal mask on the front side (104); wherein the second laser drilling is performed without a conformal mask on the back side (106); wherein the first laser drilling is carried out without previously forming a window in the first electrically conductive layer structure (108); wherein the second laser drilling is carried out without previously forming a window in the second electrically conductive layer structure (110); wherein the first laser drilling is carried out with a narrower laser beam than the second laser drilling; wherein the first laser drilling is carried out to promote heat transfer in the first electrically conductive layer structure (108) in a horizontal direction and to inhibit heat transfer in a vertical direction, the method in particular comprising promoting heat transfer in the horizontal direction and inhibiting heat transfer in the vertical direction by operating a laser beam during the first laser drilling at an unstable processing point; wherein at least one of the first laser drilling and the second laser drilling comprises only a single laser shot; wherein at least one of the first laser drilling and the second laser drilling comprises a plurality of laser shots; wherein the method comprises performing a surface treatment, in particular forming a black oxide or providing a bonding foil, on an outer surface of at least one of the first electrically conductive layer structure (108) and the second electrically conductive layer structure (110), in each case prior to laser drilling through the first electrically conductive layer structure (108) or the second electrically conductive layer structure (110); wherein the method comprises performing the first opening process as a plasma process or as a process for patterning a photo-patternable dielectric. [3] The method according to claim 1 or 2, wherein filling the through-hole (114) with the electrically conductive filling material (118) comprises first forming a seed layer, for example by electroless plating, followed by deposition of additional electrically conductive material, for example by electroplating. [4] The method according to any one of claims 1 to 3, wherein filling the through-opening (114) with the electrically conductive filler material (118) comprises forming coating structures (116) which coat inclined side walls of the substantially trapezoidal through-opening (114) with electrically conductive filler material (118) which connects to the first electrically conductive layer structure (108) and the second electrically conductive layer structure (110). [5] The method of claim 4, wherein filling the through-hole (114) with the electrically conductive filler material (118) comprises forming a substantially horizontal bridge structure (120) connecting the coating structures (116). [6] The method according to claim 5, wherein filling the through-hole (114) with the electrically conductive filler material (118) comprises at least partially filling remaining gaps above and below the bridge structure (120) and laterally between the coating structures (116) with further electrically conductive filler material (118). [7] A component carrier (100), the component carrier (100) comprising: an electrically insulating layer structure (102) having 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 back side (106) of the electrically insulating layer structure (102); a through-opening (114), in particular a laser through-opening (114), which has a substantially trapezoidal shape and extends through the first electrically conductive layer structure (108), the electrically insulating layer structure (102) and the second electrically conductive layer structure (110); wherein the through-opening (114) tapers with a substantially trapezoidal shape from the rear side (106) to the front side (104); an electrically conductive filling material (118) which completely fills the through-opening (114), in particular the laser through-opening (114); wherein material interfaces (124) are formed in interface regions between the first electrically conductive layer structure (108) and the electrically conductive filler material (118) and between the second electrically conductive layer structure (110) and the electrically conductive filler material (118). [8] The component carrier (100) according to claim 7, comprising at least one of the following features: wherein at least one of the material interfaces (124) is beak-shaped; wherein at least a portion of the material interfaces (124) are located adjacent to corners (127) of the electrically insulating layer structure (102) between an electrically conductive filling structure on the one hand and one of the first electrically conductive layer structure (108) and the second electrically conductive layer structure (110) on the other hand; wherein the material interfaces (124) are copper / copper interfaces, in particular copper foil / clad copper interfaces. [9] The component carrier (100) according to claim 7 or 8, wherein the electrically conductive filler material (118) comprises coating structures (116) which coat inclined side walls of the substantially trapezoidal through-opening (114) with electrically conductive filler material (118) which connects to the first electrically conductive layer structure (108) and to the second electrically conductive layer structure (110). [10] The component carrier (100) according to claim 9, wherein the electrically conductive filler material (118) has a substantially horizontal bridge structure (120) connecting the coating structures (116) on the inclined side walls. [11] The component carrier (100) according to claim 10, wherein the electrically conductive filler material (118) comprises a first gap-filling structure that fills a remaining gap above the bridge structure (120) and / or a second gap-filling structure that fills a remaining gap below the bridge structure (120). [12] The component carrier (100) according to claim 11, comprising at least one further material interface (124) between the coating structures (116) and at least one of the gap-filling structures and / or between the bridge structure (120) and at least one of the gap-filling structures. [13] The component carrier (100) according to any one of claims 10 to 12, wherein a surface of the bridge structure (120) facing the front side (104) is concave. [14] The component carrier (100) according to any one of claims 10 to 13, wherein a surface of the bridge structure (120) facing the rear side (106) is concave. [15] The component carrier (100) according to claim 13 or 14, wherein a surface of the bridge structure (120) facing the rear side (106) is concave, and wherein the concave surface of the bridge structure (120) facing the rear side (106) has a greater curvature than the concave surface of the bridge structure (120) facing the front side (104). [16] The component carrier (100) according to one of claims 7 to 15, wherein a lateral outer surface of the electrically conductive filler material (118) has an inclined, substantially straight shape, wherein in particular a smallest outer diameter of the electrically conductive filler material (118) is located on the front side (104). [17] The component carrier (100) according to one of claims 7 to 15, wherein a thickness of the electrically conductive layer structure is less than 110 µm, in particular less than 60 µm. [18] The component carrier (100) according to one of claims 7 to 17, wherein a ratio between a smaller side length of the trapezoid on the first electrically conductive layer structure (108) and a larger side length of the trapezoid on the second electrically conductive layer structure (110) is in a range between 0.6 and 0.

8. [19] The component carrier (100) according to one of claims 7 to 18, comprising at least one of the following features: further comprising a component which is mounted on and / or embedded in the electrically insulating layer structure (102) and / or at least one of the electrically conductive layer structures, wherein the component is in particular selected from a group consisting of an electronic component, an electrically non-conductive and / or electrically conductive inlay, a heat transfer unit, a light-conducting element, an energy harvesting 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 optoelectronic interface element, a voltage converter, a cryptographic component, a transmitter and / or receiver, an electromechanical transducer, an actuator, a microelectromechanical system, a microprocessor,a capacitor, a resistor, an inductor, an accumulator, a switch, a camera, an antenna, a magnetic element, another component carrier and a logic chip; wherein at least one of the electrically conductive layer structures comprises at least one of the group consisting of copper, aluminum, nickel, silver, gold, palladium and tungsten, each of said materials optionally being coated with a superconducting material such as graphene; wherein the electrically insulating layer structure (102) comprises 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 crystalline polymer, epoxy-based build-up film, polytetrafluoroethylene, a ceramic, and a metal oxide; wherein the component carrier (100) is plate-shaped; wherein the component 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.

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