Component carrier and method of manufacturing the component carrier

Abstract

Component carrier and method of manufacturing the component carrier are provided by the present application. The component carrier (100) comprises a stack (102) comprising at least one electrically conductive layer structure (104) and at least one electrically insulating layer structure (106), a through hole (108) extending vertically through the stack (102) and delimiting slanted sidewalls (110) of the stack (102), and an electrically insulating coating (112) covering part of both opposing main surfaces (114, 116) of the stack (102) and at least part of the slanted sidewalls (110) of the stack (102), in particular the whole slanted sidewalls (110) of the stack (102).

Description

[0001] Component carrier and method of manufacturing the component carrier

[0002] Field of the Invention

[0003] The invention relates to a component carrier and a method of manufacturing a component carrier.

[0004] Technological Background

[0005] In the context of growing product functionalities of component carriers equipped with one or more components and increasing miniaturization of such components as well as a rising number of components to be connected to the component carriers such as printed circuit boards, increasingly more powerful array-like components or packages having several components are being employed, which have a plurality of contacts or connections, with ever smaller spacing between these contacts. In particular, component carriers shall be mechanically robust and electrically reliable so as to be operable even under harsh conditions.

[0006] Summary of the Invention

[0007] There may be a need to provide a hole in a component carrier in a failure robust way and with high precision.

[0008] According to an exemplary embodiment of the invention, a component carrier is provided which comprises a stack comprising at least one electrically conductive layer structure and at least one electrically insulating layer structure, a through hole extending vertically through the stack and delimiting slanted sidewalls of the stack, and an electrically insulating coating covering part of both opposing main surfaces of the stack and at least part of the slanted sidewalls of the stack, in particular the whole slanted sidewalls of the stack.

[0009] According to another exemplary embodiment of the invention, a method of manufacturing a component carrier is provided, wherein the method comprises providing a stack comprising at least one electrically conductive layer structure and at least one electrically insulating layer structure, forming a through hole in the stack delimiting slanted sidewalls of the stack, and forming an electrically insulating coating on parts of both opposing main surfaces of the stack and on at least part of the slanted sidewalls, in particular the whole slanted sidewalls of the stack.

[0010] In the context of the present application, the term "component carrier" may particularly denote any support structure which is capable of accommodating one or more components thereon and / or therein for providing 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. In particular, a component carrier may also be embodied as a flexible or semirigid substrate. A component carrier may also be a hybrid board combining different ones of the above mentioned types of component carriers.

[0011] In the context of the present application, the term "stack" may particularly denote an arrangement of multiple planar layer structures which are mounted in parallel on top of one another. For example, the stack may be a laminated stack, i.e. comprising a plurality of layer structures connected by the application of heat and / or pressure.

[0012] In the context of the present application, the term "layer structure" may particularly denote a continuous layer, a patterned layer or a plurality of non- consecutive islands within a common plane.

[0013] In the context of the present application, the term "through hole" may particularly denote an opening in the component carrier structure which extends through the entire stack.

[0014] In the context of the present application, the term "vertical through hole" may particularly denote that the through hole extends through the stack so that a central axis or a symmetry axis of the through hole is perpendicular or substantially perpendicular to parallel main surfaces of the stack.

[0015] In the context of the present application, the term "vertical through hole delimiting slanted sidewalls of the stack" may particularly denote the fact that the sidewalls of the stack which define the lateral limits of the through hole are not completely oriented along a vertical direction perpendicular to main surfaces of the stack but, in a cross-sectional view, are partially or entirely inclined. The sidewalls may be straight or curved (for instance in a concave and / or convex fashion). Cross-sectional areas of the through hole may be different at different height levels of the stack. Preferably, the cross-sectional areas of the through hole may change gradually along the extension of the stack. Preferably, a through hole delimited by slanted sidewalls of a stack may be formed by laser drilling, i.e. by processing the stack with a drilling laser beam. By laser processing a layer stack with a laser beam, a through hole with slanted sidewalls may be formed when the laser parameters (such as laser light wavelength, laser power, irradiation time, etc.) are adjusted correspondingly.

[0016] In the context of the present application, the term "electrically insulating coating" may particularly denote an electrically non-conductive filling medium filling only part of the respective through hole while maintaining a void portion of the through hole. The electrically insulating coating may cover or line interior hole-defining sidewalls of the stack laterally or entirely. Such a filling medium may be dielectric (for instance electrically insulating ink).

[0017] In the context of the present application, the term "main surface" of a body (such as the stack) may particularly denote one of two largest opposing surfaces of the body. The main surfaces may be connected by circumferential side walls. The thickness of a body, such as a stack, may be defined by the vertical distance between the two opposing main surfaces.

[0018] According to an exemplary embodiment, a component carrier (such as a printed circuit board or an integrated circuit substrate) comprises a (preferably laminated) layer stack having one or more through holes. The latter may be formed so as to extend through the stack substantially perpendicular to main surfaces of the stack. Moreover, formation of the through hole(s) may be executed (for instance by laser drilling with appropriate laser operation parameters) in such a way that slanted sidewalls of the stack are delimited. Furthermore, an electrically insulating coating may be formed so that the latter coats the opposing main surfaces of the stack only partially and the slanted sidewalls of the stack partially or entirely. Advantageously, a through hole with slanted sidewalls has turned out as a proper basis for depositing an electrically insulating coating thereon, in particular in terms of homogeneity-related properties of the coating. Moreover, the area increase of the sidewall surface due to its slanted configuration may enhance the adhesion of the coating on the sidewall, which may improve mechanical integrity of the component carrier as a whole. For example, this coating may function as a through hole-related solder resist structure and may protect a covered stack surface from undesired phenomena such as corrosion, oxidation and / or mechanical impact. At the same time, a through hole defined by slanted rather than vertical sidewalls may spatially extend the through hole dimensions from one main surface to the other which may locally increase the functionally active area or volume. For example, a spatially widened end region of the through hole may be used for accommodating at least part of a component (such as an optical component). It is also possible that a spatially widened end region of the through hole may be used as an optically widened region for emitting and / or detecting light. Moreover, when applying the electrically insulating coating to the slanted sidewalls, the coating adhesion properties may be enhanced in comparison with entirely vertical sidewalls. Advantageously, exemplary embodiments of the invention may achieve a quite homogeneous sidewall coverage of a coating in a through hole.

[0019] Detailed Description of Exemplary Embodiments

[0020] In the following, further exemplary embodiments of the component carrier and the method will be explained.

[0021] In an embodiment, the method comprises forming the through hole in the stack by laser processing. In an embodiment, the through hole may be a laser through hole. The through hole may be formed in particular and preferably by laser processing. Formation of a through hole by laser processing from only one main surface of an electrically insulating layer structure may be preferred for obtaining the described shape. Advantageously, when forming the through hole by laser processing, substantially no glass fibers from prepreg material of the stack will extend into the through hole due to the impact of the laser beam. This may improve accuracy of the obtained geometry and may suppress artefacts. However, formation of a through hole may be carried out as well by other methods than laser processing, for instance by a plasma treatment, by wet etching, etc.

[0022] In an embodiment, the through hole may be an at least partly tapering through hole. In the context of the present application, the term "at least partly tapering through hole" may particularly denote a through hole becoming thinner or narrower towards one end at least along a section thereof. However, an at least partly tapering through hole may also have a non-tapering section, for instance may have a vertical section perpendicular to the surface of the stack in a cross-sectional view. More generally, an at least partly tapering through hole may have a larger cross-sectional area at one end as compared to an opposing other end. Tapering of a through hole may be continuous, for instance in accordance with a cross-section of a through hole with a sidewall being continuously straight or continuously curved (for instance in a concave or convex manner). Tapering through holes may be created by a laser drilling process, since a laser beam impacting the layer stack from one side thereof may create, when appropriate processing parameters are adjusted, a through hole having a larger diameter at a side facing a laser source as compared to another side opposing a laser source.

[0023] In particular, the whole sidewalls of the stack may be slanted. In such an embodiment, the sidewalls of the stack delimiting the through hole may be free of any vertical section. Hence, the sidewalls may be purely slanted.

[0024] For clarification it should be said that a through hole does not necessarily have to extend through an entire component carrier, but for instance through a stack only, which forms part of the thickness of the component carrier. In this case, the through hole can be seen for example as buried hole or blind hole. However, a through hole may also extend through the entire component carrier in other embodiments.

[0025] In an embodiment, the electrically insulating coating may comprise an ink or a resin. For example, such an electrically insulating coating may be a solid or liquid synthetic or natural organic polymer. An example is an epoxy resin. In another example, a resin forming at least part of the electrically insulating coating may comprise polyimide and / or polytetrafluoroethylene and / or cyanate ester resin.

[0026] In an embodiment, a distribution and / or an amount of the coating on two sides of the stack with respect to a horizontal symmetry plane extending through the stack is asymmetrical. The horizontal symmetry plane may virtually separate the stack into two halves of the same vertical thickness. When depositing the electrically insulating coating on the dedicated stack surface, the slanted sidewalls may lead to an inhomogeneous coverage in terms of coating thickness along the through hole. This may have a stabilizing impact on the component carrier as a whole.

[0027] In an embodiment, the coating has a smaller thickness at one circumferential edge (which may be the edge of one extremity of the through hole) between one main surface of the stack and the sidewalls of the stack than a larger thickness of the coating at another circumferential edge (which may be the edge of the opposing extremity of the through hole) between the opposing other main surface of the stack and the sidewalls of the stack. In particular, the circumferential edge with the larger coating thickness may correspond to the end of the through hole at which the latter leads to an obtuse angle of the adjacent stack material in a cross-sectional view. Correspondingly, the circumferential edge with the smaller (for instance zero) coating thickness may correspond to the end of the through hole at which the latter leads to an acute angle of the adjacent stack material in a cross-sectional view. For example, this is shown in Figure 1. Advantageously, this inhomogeneous coating distribution may keep the open cross-sectional area of the through hole at its narrow end sufficiently large as a consequence of the locally small coating thickness at said end. This may be of utmost advantage in particular for optical applications in which light propagates through the through hole, since the described measure may increase the functional opening size at the narrow end.

[0028] In an embodiment, one circumferential edge between one main surface of the stack and the sidewalls of the stack is free of coating. In particular referring again to Figure 1, the circumferential edge with the zero coating thickness may correspond to the end of the through hole at which the latter leads to an acute angle of the adjacent stack material in a cross-sectional view. As a result, the usable cross-sectional area at that end may be the full area of the through hole at its narrowest position. This may be an optimal condition in particular for optical applications.

[0029] In an embodiment, an opposing other circumferential edge between an opposing other main surface of the stack and the sidewalls of the stack is covered by the coating. Even a relatively thick sidewall coverage of said stack end by the coating may be acceptable without leading to functional limitations, since the slanted sidewalls provide a very large cross-sectional area at that wide end.

[0030] In an embodiment, a tapering angle (see angle [3 in Figure 1) between the slanted sidewalls and a vertical direction perpendicular to said main surfaces is in a range from 0.5° to 20°, for example in a range from 1° to 5°. Such angles may be easily obtained by laser drilling when properly adjusting wavelength, energy, irradiation duration and / or other characterizing operation parameters of the laser beam. In particular, sidewalls with pronounced slanted properties may be created by executing laser drilling when placing the laser beam only on one side of the stack during laser drilling, cutting or processing.

[0031] In an embodiment, the component carrier comprises a solder resist structure on one or both opposing main surfaces of the stack apart from the coating (wherein "apart from the coating" may denote the fact that the solder resist and the coating do not overlap or contact in the described embodiment). In the context of the present application, the term "solder resist structure" may particularly denote a physical structure comprising solder resist material. In particular, such a structure may be a flat layer structure covering only part of the main surfaces the stack. Solder resist material of such a solder resist structure may protect the stack or part thereof against oxidation or corrosion, in particular may protect surface portions containing a metal such as copper. Furthermore, a solder resist may optionally define one or more surface portions of a stack of a component carrier on which no solder material shall and will attach. To put it shortly, the material of a solder resist may be selected so that solder material will not attach or remain on surface regions of a stack of a component carrier which are covered by the solder resist. A solder resist, which may also be denoted as solder mask, may be a thin lacquer-like layer, for instance of polymer, that may be applied to electrically conductive surface metal (in particular copper traces of a component carrier, such as a printed circuit board (PCB)) for protection against oxidation and to prevent solder bridges from forming between closely spaced solder pads. In this context, a solder bridge may be an unintended electrical connection between two electrically conductive structures by a spot of solder. A solder resist may prevent solder bridges. Once applied as a continuous layer on a stack, one or more openings can be created in the solder resist where material shall be electrically connected with electrically conductive layer structures of the stack, for instance for connecting them electrically with one or more surface mounted components to be soldered on the stack. Such openings may be formed by patterning the continuous layer of solder resist on the stack, for example using photolithography. For example, a solder resist may be formed based on epoxy liquid which may be silk-screened through a pattern or a mask onto the stack. It is also possible to form a solder resist on the basis of a liquid photoimagea- ble solder mask ink which can be applied for example by spraying or silkscreening and can then be patterned. Furthermore, a solder resist may be created as a dry-film photoimageable solder mask which can be laminated and subsequently patterned on the stack.

[0032] In an embodiment, a thickness of the solder resist structure is larger than a thickness of the coating on the same main surface where the solder resist structure is provided. Advantageously, already a small thickness of the coating in the through hole may be sufficient for reliably protecting the exposed stack surface there.

[0033] In an embodiment, a material of the coating is an ink or a solder resist. When the coating is an ink, it may for instance provide the function of a colorant. Additionally or alternatively, it is also possible that the coating may be a solder resist (for instance with properties as defined above) or a further solder resist structure made of another material than the solder resist structure.

[0034] Thus, the coating and the solder resist structure may be different kinds of solder resist. In the context of the present application, the term "different kinds of solder resist" may particularly denote solder resists having different material compositions. For example, different kinds of solder resist may be a combination of at least two of at least one epoxy liquid-based solder resist, at least one liquid photoimageable solder mask ink, and / or at least one dry-film photoimageable solder mask. Different material compositions of different kinds of solder resist may lead to different properties of each respective solder resist, for instance in terms of electric isolation, anti-adhesion properties with respect to solder, color (for example green, blue, black), corrosion protection strength, coefficient of thermal expansion (CTE), mechanical strength, etc. Hence, two different kinds of solder resist may be provided on part of or on the entire surface of the stack. In an embodiment, a horizontal extension of the coating covering one main surface of the stack is lower than a horizontal extension of the solder resist structure on said main surface. In particular, it may be possible to define a recess between said coating and said solder resist structure, more particularly having an electrically conductive layer structure exposed in said recess. For example, the solder resist structure may provide the functionality of protecting the main surfaces of the stack, whereas the coating may predominantly lead to an electrically insulating protection of the interior stack sidewalls. The extension of the coating up to a portion of the main surfaces of the stack being directly connected to the through hole may lead to an improved adhesion of the coating on the stack surface while also contributing to a surface protection of that connected portions of the main surfaces. A larger thickness of the solder resist compared with the coating may lead to a reliable dielectric protection of the main surfaces against corrosion, etc., while the smaller thickness of the coating may keep the functional through hole area or volume sufficiently large.

[0035] In an embodiment, a horizontal extension length of the coating covering one main surface of the stack differs from another horizontal extension length of the coating covering the opposing other main surface of the stack. By taking this measure, the different areas of two opposing main surfaces may be reflected or taken into account in terms of dielectric coating.

[0036] In an embodiment, the component carrier comprises a component, or a plurality of components. The one or more components may be surface mounted on the stack or embedded in the stack. In the context of the present application, the term "component" may particularly denote any bulky rather than layer-type block. The component may be an electronic component, such as an active (for example a semiconductor chip or semiconductor package) or passive (for instance a capacitor or an inductor) electronic component embedded or to be embedded within an interior of the component carrier. However, the component may also be a non-electronic component without electronic functionality. For example, the component may be a component with thermal functionality, such as a heat removal and / or heat spreading functionality. For example, the component may be a metal (for instance copper) block and / or ceramic block. Preferably, said at least one component may be an optical component, i.e. a component with optical functionality. For example, the component carrier with component may be a camera module. Instance, the optical component may comprise an optical sensor. Such an optical sensor may be configured for capturing image data, video data or sensor data. Additionally or alternatively, the optical component may provide an optical emitter function. Such an optical emitter may be configured for emitting image data or video data. During operation of the component carrier with one or more optical components, optical electromagnetic radiation (such as visible light, infrared light and / or ultraviolet light) may propagate through the through hole.

[0037] Without wishing to be bound to a specific theory, it is presently believed that the coating and solder resist on the surface of the component carrier may prevent so-called momentary blazing phenomena resulting from light reflected by an exposed trace.

[0038] In an embodiment, the component carrier comprises a component, for example an optical component, being accommodated at least partially inside the through hole. Hence, at least part of the through hole may function for accommodating at least part of at least one optical component. Such an embodiment is shown, for example, in Figure 14. In a preferred example, the component is in direct contact with the electrically insulating coating.

[0039] In an embodiment, the component carrier comprises a component, for example an optical component, being surface-mounted on one main surface of the stack so as to cover the through hole. In particular, said at least one optically component may face the through hole. Such an embodiment is shown, for example, in Figure 13. For instance, at least one optically sensitive detection element and / or at least one optical emitting element of the at least one optical component may be aligned with the through hole in the stack, so that the at least one optical component mounted on the stack may functionally cooperate with electromagnetic radiation propagating through the stack and / or may emit electromagnetic radiation into the through hole. For example, said functional cooperation may comprise an alignment of the optical component with the through hole so that the optical component is capable of detecting light propagating through the through hole. Additionally or alternatively, said functional cooperation may comprise an alignment of the optical component with the through hole so that the optical component is capable of emitting light for propagating through the through hole.

[0040] In an embodiment, a maximum thickness of the coating on one side of the sidewalls differs from a maximum thickness of the coating on another (in particular opposing) side of the sidewalls by a value in a range from 1% to 20%, for example by a value in a range from 2% to 10%. For example, a "thickness" of the coating on a surface portion of the sidewall may be a coating thickness perpendicular to said surface portion (for instance perpendicular to a tangent on said surface portion). A "maximum thickness" on a sidewall side may be the largest thickness on said sidewall side between the two opposing main surfaces of the stack. More precisely, an absolute value of a ratio between, on the one hand, a difference between a maximum thickness of the coating on one side of the sidewalls and a maximum thickness of the coating on another side of the sidewalls and, on the other hand, the maximum thickness of the coating on said one side of the sidewalls may be in at least one of the mentioned ranges. Hence, homogeneity of the sidewall coverage of the coating may be enhanced, since maximum thickness variations on different sidewalls portions may be limited to not more than 20%, preferably to not more than 10%.

[0041] In an embodiment, the slanted sidewalls taper from one of said main surfaces, having a larger amount of the coating at one circumferential edge between said main surface and the sidewalls, towards the other one of said main surfaces, having a smaller amount of the coating at another circumferential edge between said other main surface and the sidewalls. In an embodiment, said main surface may have a smaller amount (for instance mass or volume) of the coating on said main surface than on said other main surface which has a larger amount of the coating on said other main surface. To put it shortly, the coating thickness may be larger on one circumferential edge with larger through hole diameter compared with the coating thickness on the opposing other circumferential edge with smaller through hole diameter (see for example Figure 1).

[0042] In an embodiment, said coating covering part of both opposing main surfaces of the stack and at least part of the slanted sidewalls of the stack forms an integral continuous structure. Thus, an uninterrupted region may be protected by said coating, thereby preventing unprotected weak parts of the stack surface. Furthermore, this may promote proper adhesion between coating and stack.

[0043] In an embodiment, an internal opening defined by the coating is a slanted opening having an inclination angle with respect to a vertical direction smaller than an inclination angle with respect to the vertical direction of the slanted through hole. In particular, the internal opening defined by the coating may be a slanted opening having an inclination value smaller than the inclination value of the slanted through hole. In other words, an inhomogeneous sidewall coverage of the coating may at least partially compensate the varying thickness of the through hole between the stack sidewalls. To put it shortly, tapering may be less pronounced at the exposed surface of the coating compared with the sidewalls of the stack.

[0044] In an embodiment, the method comprises applying the coating on the sidewalls and on parts of the main surfaces using a roller. For instance, such a roller may be a cylindrical body rotating about its central symmetry axis during operation, for instance during application of the coating. Such a roller may be moved, while rotating, longitudinally along a corresponding main surface of the stack. It has been surprisingly found that by forming the coating using a roller (rather than a scarper), enhanced balance of sidewall thickness may be achieved. This may keep the through hole center at a consistent position before and after coating. However, alternative methods of forming the coating are possible, like spray coating, screen printing, etc.

[0045] In an embodiment, the method comprises applying the coating on the sidewalls and on parts of the main surfaces using a pair of rollers (which may both be embodied as described above for the roller) rolling along the opposing main surfaces of the stack, preferably rolling simultaneously along the opposing main surfaces of the stack. By taking this measure, excellent accuracy of the coating and a highly precise characteristic of the coated through hole may be achieved.

[0046] In an embodiment, a stack of the component carrier comprises at least one electrically insulating layer structure and at least one electrically conductive layer structure. For example, the component carrier may be a laminate of the mentioned electrically insulating layer structure(s) and electrically conductive layer structure(s), in particular formed by applying mechanical pressure and / or thermal energy. The mentioned stack may provide a plate-shaped component carrier capable of providing a large mounting surface for further components and being nevertheless very thin and compact.

[0047] In an embodiment, the component carrier is shaped as a plate. This contributes to the compact design, wherein the component carrier nevertheless provides a large basis for mounting components thereon. Furthermore, in particular a naked die as example for an embedded electronic component, can be conveniently embedded, thanks to its small thickness, into a thin plate such as a printed circuit board.

[0048] In an embodiment, the component carrier is configured as one of the group consisting of a printed circuit board, a substrate (in particular an IC substrate), and an interposer.

[0049] In the context of the present application, the term "printed circuit board" (PCB) may particularly denote a plate-shaped component carrier which is formed by laminating several electrically conductive layer structures with several electrically insulating layer structures, for instance by applying pressure and / or by the supply of thermal energy. As preferred materials for PCB technology, the electrically conductive layer structures are made of copper, whereas the electrically insulating layer structures may comprise resin and / or glass fibers, so-called prepreg or FR.4 material. The various electrically conductive layer structures may be connected to one another in a desired way by forming holes through the laminate, for instance by laser drilling or mechanical drilling, and by partially or fully filling them with electrically conductive material (in particular copper), thereby forming vias or any other through hole connections. The filled hole either connects the whole stack, (through hole connections extending through several layers or the entire stack), or the filled hole connects at least two electrically conductive layers, called via. Similarly, optical interconnections can be formed through individual layers of the stack in order to receive an electro-optical circuit board (EOCB). Apart from one or more components which may be embedded in a printed circuit board, a printed circuit board is usually configured for accommodating one or more components on one or both opposing surfaces of the plate- shaped printed circuit board. They may be connected to the respective main surface by soldering. A dielectric part of a PCB may be composed of resin with reinforcing fibers (such as glass fibers).

[0050] In the context of the present application, the term "substrate" may particularly denote a small component carrier. A substrate may be a, in relation to a PCB, comparably small component carrier onto which one or more components may be mounted and that may act as a connection medium between one or more chip(s) and a further PCB. For instance, a substrate may have substantially the same size as a component (in particular an electronic component) to be mounted thereon (for instance in case of a Chip Scale Package (CSP)). In another embodiment, the substrate may be substantially larger than the assigned component (for instance in a flip chip ball grid array, FCBGA, configuration). More specifically, a substrate can be understood as a carrier for electrical connections or electrical networks as well as component carrier comparable to a printed circuit board (PCB), however with a considerably higher density of laterally and / or vertically arranged connections. Lateral connections are for example conductive paths, whereas vertical connections may be for example drill holes. These lateral and / or vertical connections are arranged within the substrate and can be used to provide electrical, thermal and / or mechanical connections of housed components or unhoused components (such as bare dies), particularly of IC chips, with a printed circuit board or intermediate printed circuit board. Thus, the term "substrate" also includes "IC substrates". A dielectric part of a substrate may be composed of resin with reinforcing particles (such as reinforcing spheres, in particular glass spheres).

[0051] The substrate or interposer may comprise or consist of at least a layer of glass, silicon (Si) and / or a photoimageable or dry-etchable organic material like epoxy-based build-up material (such as epoxy-based build-up film) or polymer compounds (which may or may not include photo- and / or thermosensitive molecules) like polyimide or polybenzoxazole.

[0052] In an embodiment, the at least one electrically insulating layer structure comprises at least one of the group consisting of a resin or a polymer, such as epoxy resin, cyanate ester resin, benzocyclobutene resin, bismaleimide-tria- zine resin, polyphenylene derivate (e.g. based on polyphenylenether, PPE), polyimide (PI), polyamide (PA), liquid crystal polymer (LCP), polytetrafluoroethylene (PTFE) and / or a combination thereof. Reinforcing structures such as webs, fibers, spheres or other kinds of filler particles, for example made of glass (multilayer glass) in order to form a composite, could be used as well. A semi-cured resin in combination with a reinforcing agent, e.g. fibers impregnated with the above-mentioned resins is called prepreg. These prepregs are often named after their properties e.g. FR4 or FR5, which describe their flame retardant properties. Although prepreg particularly FR4 are usually preferred for rigid PCBs, other materials, in particular epoxy-based build-up materials (such as build-up films) or photoimageable dielectric materials, may be used as well. For high frequency applications, high-frequency materials such as polytetrafluoroethylene, liquid crystal polymer and / or cyanate ester resins, may be preferred. Besides these polymers, low temperature cofired ceramics (LTCC) or other low, very low or ultra-low DK materials may be applied in the component carrier as electrically insulating structures.

[0053] In an embodiment, the at least one electrically conductive layer structure comprises at least one of the group consisting of copper, aluminum, nickel, silver, gold, palladium, tungsten, magnesium, carbon, (in particular doped) silicon, titanium, and platinum. Although copper is usually preferred, other materials or coated versions thereof are possible as well, in particular coated with supra-conductive material or conductive polymers, such as graphene or poly(3,4-ethylenedioxythiophene) (PEDOT), respectively.

[0054] At least one component may be embedded in and / or surface mounted on the stack. The component and / or the at least one further component can be selected from a group consisting of an electrically non-conductive inlay, an electrically conductive inlay (such as a metal inlay, preferably comprising copper or aluminum), a heat transfer unit (for example a heat pipe), a light guiding element (for example an optical waveguide or a light conductor connection), an electronic component, or combinations thereof. An inlay can be for instance a metal block, with or without an insulating material coating (IMS-in- lay), which could be either embedded or surface mounted for the purpose of facilitating heat dissipation. Suitable materials are defined according to their thermal conductivity, which should be at least 2 W / mK. Such materials are of- ten based, but not limited to metals, metal-oxides and / or ceramics as for instance copper, aluminium oxide (AI2O3) or aluminum nitride (AIN). In order to increase the heat exchange capacity, other geometries with increased surface area are frequently used as well. Furthermore, a component can be an active electronic component (having at least one p-n-junction implemented), a passive electronic component such as a resistor, an inductance, or capacitor, an electronic chip, a storage device (for instance a DRAM or another data memory), a filter, an integrated circuit (such as field-programmable gate array (FPGA), programmable array logic (PAL), generic array logic (GAL) and complex programmable logic devices (CPLDs)), a signal processing component, a power management component (such as a field-effect transistor (FET), metal- oxide-semiconductor field-effect transistor (MOSFET), complementary metal- oxide-semiconductor (CMOS), junction field-effect transistor (JFET), or insulated-gate field-effect transistor (IGFET), all based on semiconductor materials such as silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), gallium oxide (GazOs), indium gallium arsenide (InGaAs), indium phosphide (InP) and / or any other suitable inorganic compound), an optoelectronic interface element, a light emitting diode, a photocoupler, a voltage converter (for example 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 inductance, 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 can be used as a component. Such a magnetic element may be a permanent magnetic element (such as a ferromagnetic element, an antiferromagnetic element, a multiferroic element or a ferrimagnetic element, for instance a ferrite core) or may be a paramagnetic element. However, the component may also be an IC substrate, an interposer or a further component carrier, for example 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. Moreover, also other components, in particular those which generate and emit electromagnetic radiation and / or are sensitive with regard to electromagnetic radiation propagating from an environment, may be used as component.

[0055] In an embodiment, the component carrier obtained from the component carrier structure is a laminate-type component carrier. In such an embodiment, the component carrier is a compound of multiple layer structures which are stacked and connected together by applying a pressing force and / or heat.

[0056] After processing interior layer structures of the component carrier, it is possible to cover (in particular by lamination) one or both opposing main surfaces of the processed layer structures symmetrically or asymmetrically with one or more further electrically insulating layer structures and / or electrically conductive layer structures. In other words, a build-up may be continued until a desired number of layers is obtained.

[0057] After having completed formation of a stack of electrically insulating layer structures and electrically conductive layer structures, it is possible to proceed with a surface treatment of the obtained layers structures or component carrier.

[0058] In particular, an electrically insulating solder resist may be applied to one or both opposing main surfaces of the layer stack or component carrier in terms of surface treatment. For instance, it is possible to form such a solder resist on an entire main surface and to subsequently pattern the layer of solder resist so as to expose one or more electrically conductive surface portions which shall be used for electrically coupling the component carrier to an electronic periphery. The surface portions of the component carrier remaining covered with solder resist may be efficiently protected against oxidation or corrosion, in particular surface portions containing copper.

[0059] It is also possible to apply a surface finish selectively to exposed electrically conductive surface portions of the component carrier in terms of surface treatment. Such a surface finish may be an electrically conductive cover material on exposed electrically conductive layer structures (such as pads, conductive tracks, etc., in particular comprising or consisting of copper) on a surface of a component carrier. If such exposed electrically conductive layer structures are left unprotected, then the exposed electrically conductive component car- rier material (in particular copper) might oxidize, making the component carrier less reliable. A surface finish may then be formed for instance as an interface between a surface mounted component and the component carrier. The surface finish has the function to protect the exposed electrically conductive layer structures (in particular copper circuitry) and enable a joining process with one or more components, for instance by soldering. Examples for appropriate materials for a surface finish are Organic Solderability Preservative (OSP), Electroless Nickel Immersion Gold (ENIG), Electroless Nickel Immersion Palladium Immersion Gold (ENIPIG), Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG), gold (in particular hard gold), chemical tin (chemical and electroplated), nickel-gold, nickel-palladium, etc. Also nickel-free materials for a surface finish may be used, in particular for high-speed applications. Examples are ISIG (Immersion Silver Immersion Gold), and EPAG (Electroless Palladium Autocatalytic Gold).

[0060] The aspects defined above and further aspects of the invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to these examples of embodiment.

[0061] Figure 1 illustrates a cross-sectional view of a component carrier according to an exemplary embodiment of the invention.

[0062] Figure 2 illustrates an image of a component carrier according to an exemplary embodiment of the invention.

[0063] Figure 3 to Figure 7 illustrate different views of structures obtained during carrying out a method of manufacturing a component carrier, shown in Figure 7, according to an exemplary embodiment of the invention.

[0064] Figure 8 to Figure 12 show structures obtained during manufacturing a component carrier, shown in Figure 12, according to an exemplary embodiment of the invention.

[0065] Figure 13 illustrates a cross-sectional view of a component carrier according to an exemplary embodiment of the invention.

[0066] Figure 14 illustrates a cross-sectional view of a component carrier according to another exemplary embodiment of the invention.

[0067] The illustrations in the drawings are schematic. In different drawings, similar or identical elements are provided with the same reference signs.

[0068] Before, referring to the drawings, exemplary embodiments will be described in further detail, some basic considerations will be summarized based on which exemplary embodiments of the invention have been developed.

[0069] In conventional approaches of forming an ink-type coating on a sidewall of a stack delimiting a through hole of a component carrier, the ink thickness on a cavity sidewall may be highly unbalanced. As a result, a cavity center position during the coating process may become unstable, i.e. it cannot be kept consistent before and after coating. A distance of a cavity center to a copper pad, as reference, may be unstable as well. Thus, conventional approaches cannot create a balanced sidewall thickness, which may cause a shift of a cavity center after coating. Conventionally, it may not be possible to control a distance of a cavity center to a pad with a sufficiently small tolerance. Sidewall coating on through holes of component carrier stacks may be quite uncontrolled and unsatisfactory in conventional approaches.

[0070] According to an exemplary embodiment of the invention, a (for instance printed circuit board-type) component carrier with (for example laminated) layer stack is provided with an at least essentially vertical through hole extending between a front side and a back side of the stack. Despite of the essentially vertical extension of the through hole through the stack, its lateral sidewalls providing an interface to the circumferential stack material may be slanted or inclined rather than extending vertically. For instance, the through hole may have a frustoconical shape. Such a shape may be created for example by laser drilling with correspondingly adjusted operation parameters. In addition, an electrically insulating coating may be deposited on a surface portion of the stack including parts of the opposing main surfaces and the slanted sidewalls or part thereof. For example, said coating or lining may provide a solder resist functionality for providing chemical and / or mechanical protection. A through hole defined by slanted sidewalls may provide advantageous properties for a component (in particular an optical component) to be mounted on a main surface of the stack with functional access to the through hole and / or to be mounted at least partially in the through hole. Preferably, the component may be in direct contact with the electrically insulating coating, in particular positioned on the slanted sidewall and optionally on one main surface of the stack. Advantageously, the described architecture may make it possible to obtain a more or even highly balanced sidewall thickness of a stack coating in a through hole avoiding an excessive center shift due to coating.

[0071] In particular, an exemplary embodiment provides a method of ink coating on a cavity hole in a stack of a component carrier. In such an embodiment, the coating or ink thickness on a cavity sidewall may be balanced. In particular, a left-to-right sidewall thickness gap may be reduced to less than 20 pm. Moreover, a through or cavity center position can be kept substantially consistent before and after coating (for instance a shift may be rendered smaller than 10 pm). In particular, a distance of a cavity center to a metallic reference pad (such as a copper pad) may be stable, and a tolerance can be controlled within for example 25 pm or less. Thus, it may be possible to obtain a balanced sidewall thickness, which may keep the cavity (or through hole) center in a consistent position before and after coating. Consequently, it may be possible to control a distance of a cavity center to a pad within a small tolerance.

[0072] The mentioned and / or other advantages may be particularly pronounced when the component carrier with a component mounted in alignment with the coated through hole is implemented as a camera module.

[0073] Figure 1 illustrates a cross-sectional view of a component carrier 100 according to an exemplary embodiment of the invention. In the shown embodiment, component carrier 100 is embodied as a printed circuit board (PCB). However, component carrier 100 may also be an integrated circuit (IC) substrate, etc.

[0074] Component carrier 100 according to Figure 1 comprises a laminated layer stack 102 comprising a plurality of electrically conductive layer structures 104 and of electrically insulating layer structures 106. Stack 102 of Figure 1 may comprise layers and vias (not shown) in a build-up construction. It is in particular possible that a stack 102 is provided being embodied with a core in a layers stack.

[0075] The electrically conductive layer structures 104 may comprise patterned copper layers which may form horizontal pads and / or horizontal wiring structures. Additionally, the electrically conductive layer structures 104 may comprise vertical through connections such as copper pillars and / or copper filled laser vias. Additionally or alternatively, mechanical plated through holes (PTH) may also be used as vertical through connections. Moreover, the stack 102 of the component carrier 100 may comprise one or more electrically insulating layer structures 106 (such as one or more prepreg sheets, resin sheets or cores made of FR.4 material). Ajinomoto Build-Up Film ® (ABF) materials are also possible for at least part of the electrically insulating layer structures 106, in particular when the component carrier 100 is embodied as an IC substrate. Also surface finish (like ENIG or ENEPIG, etc.) may be optionally applied on the top side and / or on the bottom side of the stack 102 (not shown).

[0076] As shown as well in Figure 1, a through hole 108 is formed in stack 102 and extends vertically through the entire stack 102. When forming through holes 108 by laser drilling or laser cutting with appropriate laser parameters (such as laser wavelength, laser energy, irradiation time, pulsed or continuous irradiation, etc.) and a laser source (not shown) arranged on the bottom side of the stack 102 according to Figure 1 only, the through hole 108 can be defined by and between slanted sidewalls 110 of the stack 102 leading to a tapering through hole 108. Slanted (rather than vertical) sidewalls 110 of the stack 102 include an angle p^0 with a vertical direction 130 being perpendicular to opposing horizontal main surfaces 114, 116 of stack 102. According to Figure 1, the through hole 108 has a substantially frustoconical shape.

[0077] Still referring to Figure 1, an electrically insulating coating 112 may be formed to cover part of both opposing main surfaces 114, 116 of the stack 102 and the whole slanted sidewalls 110 of the stack 102. More specifically, the electrically insulating coating 112 lines the entire sidewalls 110 defining through hole 108 and also lines a respective annular section of each of the main surfaces 114, 116 which directly surrounds the through hole 108 on both ends. A circumferential edge 120 between sidewalls 110 and main surface 114 where sidewalls 110 and circumferential edge 120 include an acute (rather than obtuse) angle may remain uncovered by electrically insulating coating 112, i.e. may be locally exposed. A horizontal extension length L of the coating 112 covering one main surface 114 of the stack 102 may differ from another horizontal extension length I of the coating 112 covering the opposing other main surface 116 of the stack 102. An internal opening of through hole 108 with now limited size as defined by the coating 112 may be a slanted opening which may have an inclination angle s with respect to vertical direction 130 which is smaller than the inclination angle [3 of the sidewalls 110 with respect to the vertical direction 130.

[0078] For instance, the electrically insulating coating 112 may be an ink or a solder resist. An ink may comprise a colorant for providing the electrically insulating coating 112 with a defined color. A solder resist may protect the covered surface of stack 102, for instance against corrosion or oxidation, for ensuring dielectric isolation, for providing a mechanical protection, etc.

[0079] As shown in Figure 1, a distribution and an amount (in terms of volume and mass) of the coating 112 on two sides of the stack 102 with respect to a horizontal symmetry plane 118 extending centrally through the stack 102 is asymmetrical. Hence, different amounts of ink or coating 112 may be present on the partial surfaces of the stack 102 above and below the horizontal symmetry plane 118. More precisely, the amount of coating 112 may be larger below the horizontal symmetry plane 118 than above the horizontal symmetry plane 118. Correspondingly, a larger mass or volume of coating 112 may be present on the half of the stack 102 corresponding to the larger angle between main surface 116 and sidewalls 110 as compared with the other half of the stack 102 corresponding to the smaller angle between main surface 114 and sidewalls 110.

[0080] The illustrated distribution of material of coating 112 in and around the through hole 108 keeps a major part of the interior volume of the through hole 108 unfilled or empty. Said unfilled or empty volume of through hole 108 may then be used as a functional volume for an application, in particular for an optical application (see Figure 13 and Figure 14). This allows for an improved functionality and / or reduced space consumption for forming component carrier 100.

[0081] Again referring to Figure 1, the coating 112 may have a smaller thickness d at the one circumferential edge 120 between main surface 114 of the stack 102 and the sidewalls 110 of the stack 102 compared with a larger thickness D of the coating 112 at an opposing other circumferential edge 122 between the opposing other main surface 116 of the stack 102 and the sidewalls 110 of the stack 102. As shown, thickness d=0 in the illustrated embodiment, whereas in other embodiments the equation D>d^0 may be fulfilled (see Figure 12). In the embodiment of Figure 1 however, said circumferential edge 120 between main surface 114 of the stack 102 and the sidewalls 110 of the stack 102 is free of coating 112 (d=0), whereas the opposing other circumferential edge 122 between the opposing other main surface 116 of the stack 102 and the sidewalls 110 of the stack 102 is covered by the coating 112 (D>0). This configuration has advantages: Due to the slanted sidewalls 110 of stack 102 delimiting through hole 108, the stack surface area delimiting through hole 108 and being covered by electrically insulating coating 112 may be increased as compared to vertical sidewalls. This increased surface coverage by coating 112 may have a positive impact on adhesion. At the same time, the coating thickness is locally reduced where the diameter of the through hole 108 is minimum, i.e. at upper main surface 114. This keeps the functional hole opening large while ensuring proper mechanical integrity of the component carrier 100.

[0082] For example, tapering angle [3 between the slanted sidewalls 110 and vertical direction 130 perpendicular to said main surfaces 114, 116 may be in a range from 1° to 5°. Alternatively, tapering angle [3 between the slanted sidewalls 110 and vertical direction 130 perpendicular to said main surfaces 114, 116 may be in a range from 6° to 45°. The tapering angle [3 may also vary around a perimeter of the through hole 108, for instance in view of a slight inclination of a drilling or cutting laser beam with respect to the main surfaces 114, 116, spatial energy variations of the drilling or cutting laser beam, etc.

[0083] In a further example, the electrically insulating coating 112 may have a concave shaped portion (as can be seen in Figure 1). Alternatively, the electrically insulating coating 112 may have a convex shaped portion. This may increase the surface area toward the through hole 108 and may thus enable a reliable mechanical interaction with component 126.

[0084] As shown as well in Figure 1, a solder resist structure 124 may be applied on the opposing main surfaces 114, 116 of the stack 102 in surface regions apart from the coating 112. Also the coating 112 may be embodied as a further solder resist structure and may be made of another material than (or may be made of the same material as) the solder resist structure 124. When the materials of solder resist structure 124 and solder resist-type coating 112 are different from each other, this may allow to adjust the local solder resist properties of component carrier 100 separately and individually. In the shown embodiment, a thickness B of the solder resist structure 124 on the respective one of the main surfaces 114, 116 is larger than a thickness b of the coating 112 on the respectively same main surface 114, 116. Alternatively, the thickness B of the solder resist structure 124 on the respective one of the main surfaces 114, 116 may be smaller than the thickness b of the coating 112 on the respectively same main surface 114, 116. Furthermore, a horizontal extension of the coating 112 covering the respective one of the main surfaces 114, 116 of the stack 102 is lower than a horizontal extension of the solder resist structure 124 on said respective main surface 114, 116. Alternatively, a horizontal extension of the coating 112 covering the respective one of the main surfaces 114, 116 of the stack 102 may be higher than a horizontal extension of the solder resist structure 124 on said respective main surface 114, 116.

[0085] Preferably, a lateral recess may be formed between said coating 112 and said solder resist structure 124 on the respective one of the main surfaces 114, 116, so that coating 112 and solder resist structure 124 do not overlap or contact in a lateral direction. This may allow to expose an electrically conductive layer structure 104, such as a pad (for instance a copper pad), exposed in said recess between solder resist-type coating 112 and solder resist structure 124 for connection purposes. Another electrically conductive layer structure 104 on the respective one of the main surfaces 114, 116, such as a further pad or wiring structure (for instance a further copper pad or wiring structure), may be covered by the solder resist structure 124 for protection purposes. Although not shown, it may also be possible that coating 112 and solder resist structure 124 overlap or contact with each other.

[0086] Advantageously, a maximum thickness H of the coating 112 on one side of the sidewalls 110 may differ from a maximum thickness h of the coating 112 on another side of the sidewalls 110 by a value which is preferably in a range from 2% to 10% (in particular, the absolute value of (H-h) / H may be in a range from 2% to 10%). Thus, the homogeneity of the sidewall coverage by coating 112 may be higher than in conventional approaches. This may have a positive impact on the mechanical integrity of the component carrier 100, so that undesired phenomena such as warpage and delamination may be suppressed. Due to the high degree of homogeneity of sidewall coverage by coating 112, there may also be no or no noteworthy spatial shift of the center of the through hole 108 due to the deposition of coating 112 compared with the scenario before said deposition.

[0087] As shown, the slanted sidewalls 110 taper from main surface 116, having a larger amount of the coating 112 at one circumferential edge 122 between said main surface 116 and the sidewalls 110, towards the other main surface 114, having a smaller amount of the coating 112 at another circumferential edge 120 between said other main surface 114 and the sidewalls 110.

[0088] Figure 2 illustrates an image of a component carrier 100 according to an exemplary embodiment of the invention. Many of the parameters and properties described referring to Figure 1 can be seen in Figure 2 as well. In this embodiment, the value of D may be zero or almost zero.

[0089] Figure 3 to Figure 7 illustrate different views of structures obtained during carrying out a method of manufacturing a component carrier 100, shown in Figure 7, according to an exemplary embodiment of the invention.

[0090] Referring to the three-dimensional view of Figure 3, a laminated layer stack 102 is illustrated which may comprise electrically conductive layer structures 104 and electrically insulating layer structures 106 (not shown), which may be embodied as described referring to Figure 1. A through hole 108 has been formed in the stack 102 by laser drilling or laser cutting for delimiting slanted sidewalls 110 of the stack 102. Furthermore, a solder resist structure 124 has been applied and patterned on a portion of main surface 114 of stack 102.

[0091] Referring to Figure 4 (showing a plan view) and Figure 5 (showing a side view), a process of covering a surface portion of the component carrier pre-form of Figure 3 will be explained. As shown also in Figure 6, the ink-type or solder resist-type coating 112 may be applied on the entire sidewalls 110 and on directly connected parts of the main surfaces 114, 116 using rollers 128 moving with a combined longitudinal and rotating motion during coating application in a way as is shown by arrows 150. During applying the material of the coating 112 on the sidewalls 110 and on the connected parts of the main surfaces 114, 116, a pair of rollers 128 may be used which roll along the opposing main surfaces 114, 116 of the stack 102. Preferably, the rollers 128 roll simultaneously along the opposing main surfaces 114, 116 of the stack 102. By taking this measure, the material of the coating 112 can be applied evenly to substantially the entire slanted sidewalls of the stack 102 delimiting through hole 108. The homogeneity of the obtained sidewall coverage by coating 112 may be significantly improved by using rollers 128 impacting simultaneously opposing main surfaces 114, 116 of stack 102 for lining sidewalls 110 delimiting slanted through hole 108, compared with conventional approaches which apply coating for instance using a scarper.

[0092] Referring to Figure 6, the result of the described homogeneous application of coating 112 onto the slanted sidewalls 110 of stack 102 is shown. More precisely, the result of the described manufacturing method is an electrically insulating coating 112 on annular parts of both opposing main surfaces 114, 116 of the stack 102 and on the entire surface area of slanted sidewalls 110 of stack 102.

[0093] However, alternative methods (compared with Figure 4 and Figure 5) of forming the coating are possible, like spray coating, screen printing, etc.

[0094] Referring to Figure 7, characteristics of the obtained component carrier 100 are illustrated. Generally, the described manufacturing method may allow to create balanced sidewall thickness, which may keep the cavity center consistent before and after coating. Moreover, this may allow to control a distance of a cavity center to a pad and with small tolerance.

[0095] As shown, a thickness of a cavity side wall can be balanced, so that a difference between left sidewall thickness 152 and right sidewall thickness 154 may be less than 20 pm.

[0096] As shown as well, a cavity center position can remain consistent before and after coating with a shift of less than 10 pm. Figure 7 shows a cavity center after coating with reference sign 156 and a cavity center before coating with reference sign 158.

[0097] Now referring to reference sign 160 in Figure 7, a distance of a cavity center with respect to a pad (see the electrically conductive layer structure 104 on the top side) may remain stable, and tolerances can be controlled within 25 pm or less. In an embodiment, not the entire sidewall 110 of the through hole 108 has to be inclined, but a part thereof may be vertical. Figure 8 to Figure 12 show structures obtained during manufacturing a component carrier 100, shown in Figure 12, according to an exemplary embodiment of the invention.

[0098] As shown in Figure 8, a three-dimensional view of a stack 102 (which can be constructed as described above referring to Figure 1) is shown with a patterned solder resist structure 124 covering part of main surfaces of the stack 102.

[0099] As shown in Figure 9, a through hole 108 may be formed in stack 102 by laser processing, said through hole 108 being delimited by slanted sidewalls 110.

[0100] Figure 10 shows a cross-sectional view corresponding to Figure 8. Figure 11 shows a cross-sectional view corresponding to Figure 9.

[0101] As shown in Figure 12, coating 112 may then be applied to the entire sidewalls 110 and parts of main surfaces 114, 116. As a result, a structure similar to Figure 1 can be obtained. Due to taper 162, a top cavity diameter 164 may be larger than a bottom cavity diameter 166. This difference is however partially compensated by the larger thickness D>d^0 at top cavity diameter 164 as compared to the smaller thickness d at bottom cavity diameter 166. As shown, said coating 112 covering part of both opposing main surfaces 114, 116 of the stack 102 and the slanted sidewalls 110 of the stack 102 forms an integral continuous structure. This may improve the mechanical integrity of the component carrier 100.

[0102] Figure 13 illustrates a cross-sectional view of a component carrier 100 according to an exemplary embodiment of the invention.

[0103] According to Figure 13, component carrier 100 comprises a surface mounted optical component 126. For example, component 126 may comprise an optically sensitive camera element 170 configured for capturing optical data corresponding to light propagating through the through hole 108. Component 126 may comprise electrically conductive pads 172 which may be electrically coupled with pads corresponding to electrically conductive layer structures 104 exposed on a main surface 116 of stack 102. For instance, said electric coupling may be accomplished by solder structures 174. Optical component 126 being surface-mounted on main surface 116 of the stack 102 may face and may be aligned with the through hole 108 to enable an optical communication between optically sensitive camera element 170 through hole 108 and a side of stack 102 facing away from component 126. Electromagnetic radiation, such as light 178, may propagate through the through hole 108 towards the optically sensitive camera element 170 of component 126 for optical detection. Signals relating to the detected information may be transmitted from component 126 to stack 102 via the electrically conductive pads 172 which are electrically coupled with the pads corresponding to the electrically conductive layer structures 104 exposed on main surface 116 of stack 102.

[0104] However, other ways of establishing an electrical connection are possible as well rather than connecting the electrically conductive pads 172 with the pads corresponding to the electrically conductive layer structures 104 by solder, sinter or conductive glue. For example, it may be possible to connect the electrically conductive pads 172 with the pads corresponding to the electrically conductive layer structures 104 by wire bonding, for instance using bond wires or bond ribbons. Also clips may be used for this purpose. Wire or clip bonding may also allow to couple electrically conductive pads 172 with the pads corresponding to the electrically conductive layer structures 104 being arranged side by side, for instance at the same vertical level.

[0105] Figure 14 illustrates a cross-sectional view of a component carrier 100 according to another exemplary embodiment of the invention. This embodiment may include one or more optical components 126. One optical component 126 may be accommodated inside the through hole 108.

[0106] It should be noted that the term "comprising" does not exclude other elements or steps and the "a" or "an" does not exclude a plurality. Also, elements described in association with different embodiments may be combined.

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

[0108] Implementation of the invention is not limited to the preferred embodiments shown in the figures and described above. Instead, a multiplicity of variants is possible which use the solutions shown and the principle according to the invention even in the case of fundamentally different embodiments.

Claims

Claims:

1. A component carrier (100), wherein the component carrier (100) comprises: a stack (102) comprising at least one electrically conductive layer structure (104) and at least one electrically insulating layer structure (106); a through hole (108) extending vertically through the stack (102) and delimiting slanted sidewalls (110) of the stack (102); and an electrically insulating coating (112) covering part of both opposing main surfaces of the stack (102) and at least part of the slanted sidewalls (110) of the stack (102), for example the whole slanted sidewalls (110) of the stack (102).

2. The component carrier (100) according to claim 1, wherein a distribution and / or an amount of the coating (112) on two sides of the stack (102) with respect to a horizontal symmetry plane (118) extending through the stack (102) is asymmetrical.

3. The component carrier (100) according to claim 1 or 2, wherein the coating (112) has a smaller thickness at one circumferential edge (120) between one main surface (114) of the stack (102) and the slanted sidewalls (110) of the stack (102) than a larger thickness of the coating (112) at another circumferential edge (122) between the opposing other main surface (116) of the stack (102) and the slanted sidewalls (110) of the stack (102).

4. The component carrier (100) according to any of claims 1 to 3, wherein one circumferential edge (120) between one main surface (114) of the stack (102) and the slanted sidewalls (110) of the stack (102) is free of coating (112).

5. The component carrier (100) according to claim 4, wherein an opposing other circumferential edge (122) between an opposing other main surface (116) of the stack (102) and the slanted sidewalls (110) of the stack (102) is covered by the coating (112).

6. The component carrier (100) according to any of claims 1 to 5, wherein a tapering angle (p) between the slanted sidewalls (110) and a vertical direction (130) perpendicular to said main surfaces is in a range from 0.5° to 20°, for example in a range from 1° to 5°.

7. The component carrier (100) according to any of claims 1 to 6, wherein the component carrier (100) comprises a solder resist structure (124) on one or both opposing main surfaces of the stack (102) apart from the coating (112).

8. The component carrier (100) according to claim 7, wherein a thickness of the solder resist structure (124) is larger than a thickness of the coating (112) on the same main surface where the solder resist structure (124) is provided.

9. The component carrier (100) according to claim 7 or 8, wherein the coating (112) is a further solder resist structure made of another material than the solder resist structure (124).

10. The component carrier (100) according to any of claims 7 to 9, wherein a horizontal extension of the coating (112) covering one main surface of the stack (102) is lower than a horizontal extension of the solder resist structure (124) on said main surface, in particular defining a recess between said coating (112) and said solder resist structure (124), more particularly having an electrically conductive layer structure (104) exposed in said recess.

11. The component carrier (100) according to any of claims 1 to 10, wherein a horizontal extension length (L) of the coating (112) covering one main surface (114) of the stack (102) differs from another horizontal extension length (I) of the coating (112) covering the opposing other main surface (116) of the stack (102).

12. The component carrier (100) according to any of claims 1 to 11, wherein the component carrier (100) comprises a component (126), for example an optical component, being accommodated at least partially inside the through hole (108).

13. The component carrier (100) according to any of claims 1 to 12, wherein the component carrier (100) comprises a component (126), for example an optical component, being surface-mounted on one main surface of the stack (102) so as to cover the through hole (108), in particular to face the through hole (108).

14. The component carrier (100) according to any of claims 1 to 13, wherein a material of the coating (112) is an ink or a solder resist.

15. The component carrier (100) according to any of claims 1 to 14, wherein a maximum thickness of the coating (112) on one side of the slanted sidewalls (110) differs from a maximum thickness of the coating (112) on another side of the slanted sidewalls (110) by a value in a range from 1% to 20%, for example by a value in a range from 2% to 10%.

16. The component carrier (100) according to any of claims 1 to 15, wherein the slanted sidewalls (110) taper from one of said main surfaces (116), having a larger amount of the coating (112) at one circumferential edge (122) between said main surface (116) and the slanted sidewalls (110), towards the other one of said main surfaces (114), having a smaller amount of the coating (112) at another circumferential edge (120) between said other main surface (114) and the slanted sidewalls (110).

17. The component carrier (100) according to claim 16, wherein said main surface (116) has a smaller amount of the coating (112) on said main surface (116) than said other main surface (114) which has a larger amount of the coating (112) on said other main surface (114).

18. The component carrier (100) according to any of claims 1 to 17, wherein said coating (112) covering part of both opposing main surfaces of the stack (102) and at least part of the slanted sidewalls (110) of the stack (102) forms an integral continuous structure.

19. The component carrier (100) according to any of claims 1 to 18, wherein an internal opening defined by the coating (112) is a slanted opening having an inclination angle with respect to a vertical direction (130) smaller than an inclination angle with respect to the vertical direction (130) of the slanted through hole (108).

20. A method of manufacturing a component carrier (100), wherein the method comprises: providing a stack (102) comprising at least one electrically conductive layer structure (104) and at least one electrically insulating layer structure (106); forming a through hole (108) in the stack (102) delimiting slanted sidewalls (110) of the stack (102); and forming an electrically insulating coating (112) on parts of both opposing main surfaces of the stack (102) and on at least part of the slanted sidewalls (110), for example the whole slanted sidewalls (110) of the stack (102).

21. The method according to claim 20, wherein the method comprises forming the through hole (108) in the stack (102) by laser processing.

22. The method according to claim 20 or 21, wherein the method comprises applying the coating (112) on the slanted sidewalls (110) and on parts of the main surfaces using a roller (128).

23. The method according to claim 20 or 21, wherein the method comprises applying the coating (112) on the slanted sidewalls (110) and on parts of the main surfaces using a pair of rollers (128) rolling along the opposing main surfaces of the stack (102), preferably rolling simultaneously along the opposing main surfaces of the stack (102).

Images