CN117939776A

CN117939776A - Component carrier and method for producing a component carrier

Info

Publication number: CN117939776A
Application number: CN202410197030.XA
Authority: CN
Inventors: 伊斯玛迪·宾·伊斯梅尔; 张红亮; 邱汎谊
Original assignee: AT&S Austria Technologie und Systemtechnik AG
Current assignee: AT&S Austria Technologie und Systemtechnik AG
Priority date: 2024-02-21
Filing date: 2024-02-21
Publication date: 2024-04-26

Abstract

The invention provides a component carrier and a method of manufacturing a component carrier. 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); the through hole extends vertically through the stack (102) and defines an inclined sidewall (110) of the stack (102); and an electrically insulating coating (112) covering portions of the two opposite main surfaces (114, 116) of the stack (102) and at least portions of the inclined side walls (110) of the stack (102), in particular covering portions of the two opposite main surfaces (114, 116) of the stack (102) and the entire inclined side walls (110) of the stack (102).

Description

Component carrier and method for producing a component carrier

Technical Field

The present invention relates to a component carrier and a method of manufacturing a component carrier.

Background

In the context of increasing product functions of component carriers equipped with one or more components and increasing miniaturization of such components and increasing numbers of components connected to the component carrier (e.g. printed circuit board), increasingly powerful array-like components or packages with multiple components are being employed, having multiple contacts or connections, and smaller spacing between these contacts. In particular, the component carrier should have mechanical robustness and electrical reliability in order to be operable even under severe conditions.

Disclosure of Invention

It may be desirable to provide holes in component carriers in a fault-robust manner and with high accuracy.

According to an exemplary embodiment of the present invention, there is provided a component carrier including: 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 defining an inclined sidewall of the stack; and an electrically insulating coating covering portions of the two opposite major surfaces of the stack and at least a portion of the inclined side walls of the stack, e.g. the electrically insulating coating covering portions of the two opposite major surfaces of the stack and the entire inclined side walls of the stack.

According to another exemplary embodiment of the present invention, there is provided a method of manufacturing a component carrier, 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, the through hole defining an inclined sidewall of the stack; and forming an electrically insulating coating on portions of the two opposite major surfaces of the stack and on at least portions of the inclined side walls, e.g. forming an electrically insulating coating on portions of the two opposite major surfaces of the stack and on the entire inclined side walls of the stack.

In the context of the present application, the term "component carrier" may particularly denote any support structure capable of housing one or more components on and/or in the component carrier to provide mechanical support and/or electrical connection. In other words, the component carrier may be configured as a mechanical carrier and/or an electronic carrier for the component. In particular, the component carrier may be one of a printed circuit board, an organic interposer, and an IC (integrated circuit) substrate. In particular, the component carrier may also be embodied as a flexible or semi-rigid substrate. The component carrier may also be a hybrid board incorporating different ones of the above mentioned types of component carriers.

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

In the context of the present application, the term "layer structure" may particularly denote a continuous layer, a patterned layer, or a plurality of discontinuous islands in a common plane.

In the context of the present application, the term "through hole" may particularly denote an opening in the component carrier structure extending through the entire stack.

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

In the context of the present application, the term "vertical through-hole delimiting the inclined side wall of the stack" may particularly denote the fact that: the side walls of the stack defining the lateral limits of the through holes are not entirely oriented in a vertical direction perpendicular to the main surfaces of the stack, but are partially or entirely inclined in a cross-sectional view. The sidewalls may be straight or curved (e.g., in a concave and/or convex manner). The cross-sectional area of the through holes may be different at different height levels of the stack. Preferably, the cross-sectional area of the through-holes may vary gradually along the extension of the stack. Preferably, the through holes defined by the inclined side walls of the stack may be formed by laser drilling, i.e. by treating the stack with a drilling laser beam. The stack is laser processed by means of a laser beam, whereby vias with inclined side walls can be formed with corresponding adjustment of the laser parameters, such as laser wavelength, laser power, irradiation time, etc.

In the context of the present application, the term "electrically insulating coating" may particularly denote a non-conductive filling medium filling only a part of the respective through hole while maintaining the void portion of the through hole. The electrically insulating coating may cover or be arranged laterally or completely to the inner hole defining side walls of the (line) stack. Such a filling medium may be dielectric (e.g. an electrically insulating ink).

In the context of the present application, the term "main surface" of the body (such as a stack) may particularly refer to one of the two largest opposing surfaces of the body. The major surfaces may be joined by a circumferential sidewall. The thickness of a body, such as a stack, may be defined by the vertical distance between two opposing major surfaces.

According to an exemplary embodiment, the component carrier (e.g., a printed circuit board or an integrated circuit substrate) comprises a (preferably laminated) layer stack having one or more through holes. The through holes may be formed substantially perpendicular to the main surface of the stack and extend through the stack. Furthermore, the formation of the through holes may be performed in such a way as to define inclined side walls of the stack (for example by laser drilling with appropriate laser operating parameters). Furthermore, the electrically insulating coating may be formed such that it only partially coats the opposite major surface of the stack and partially or completely coats the inclined side walls of the stack. Advantageously, vias with sloped sidewalls have proven to be a suitable basis for depositing electrically insulating coatings thereon, particularly with respect to the uniformity-related characteristics of the coating. Furthermore, the increased area of the sidewall surface due to the sloped configuration of the sidewall may enhance the adhesion of the coating to the sidewall, which may improve the mechanical integrity of the component carrier as a whole. For example, the coating may serve as a through-hole related solder resist structure and may protect the covered stack surface from undesired phenomena such as corrosion, oxidation and/or mechanical shock. At the same time, the through-holes defined by the sloped sidewalls, rather than the vertical sidewalls, may spatially extend the through-hole dimensions from one major surface to the other, which may locally increase the functional active area or volume. For example, a spatially widened end region of the through-hole may be used to accommodate at least a portion of a component (e.g., an optical component). The spatially widened end region of the through-hole may also serve as an optically widened region for emitting and/or detecting light. Furthermore, when the electrically insulating coating is applied to the inclined side wall, the coating adhesion characteristics can be enhanced as compared to a completely vertical side wall. Advantageously, exemplary embodiments of the present invention may achieve a fairly uniform sidewall coverage of the coating in the via.

Detailed description of exemplary embodiments

Hereinafter, further exemplary embodiments of the component carrier and the method will be described.

In one embodiment, the method includes forming a via in the stack by laser processing. In one embodiment, the via may be a laser via. The through-holes may be formed particularly and preferably by laser machining. To obtain the described shape, the through-holes may be formed from only one main surface of the electrically insulating layer structure, preferably by laser machining. Advantageously, when the through-holes are formed by laser machining, substantially no glass fibres of the prepreg material from the stack will extend into the through-holes due to the impact of the laser beam. This may improve the accuracy of the obtained geometry and may suppress artifacts. However, the through-holes may be formed by other methods than laser processing, for example, by plasma treatment, by wet etching, or the like.

In one embodiment, the through-hole may be an at least partially tapered through-hole. In the context of the present application, the term "at least partially tapered through hole" may particularly denote a through hole that is thinned or narrowed towards one end at least along a portion thereof. However, the at least partially tapered through hole may also have a non-tapered portion, e.g. may have a vertical portion perpendicular to the surface of the stack in a cross-sectional view. More generally, the at least partially tapered through-hole may have a larger cross-sectional area at one end than at the opposite end. The tapering of the through-hole may be continuous, for example, depending on the cross-section of the through-hole with a continuously straight or continuously curved (e.g., in a concave or convex manner) sidewall. The tapered through hole may be produced by a laser drilling process, since a laser beam impinging the layer stack from one side of the layer stack may, with appropriate process parameters adjusted, produce a through hole having a larger diameter on the side facing the laser source than on the other side opposite the laser source.

In particular, the entire side wall of the stack may be inclined. In such embodiments, the side walls of the stack defining the through-holes may be devoid of any vertical portion. Thus, the sidewalls may be purely sloped.

For the sake of clarity, it should be noted that the through-holes do not have to extend through the entire component carrier, but for example only through a stack forming part of the thickness of the component carrier. In this case, the through hole may be regarded as a buried hole or a blind hole, for example. However, in other embodiments, the through holes may also extend through the entire component carrier.

In one embodiment, the electrically insulating coating may comprise an ink or a resin. Such an electrically insulating coating may be, for example, a solid or liquid composition or a natural organic polymer. An example is epoxy. In another example, the resin forming at least a portion of the electrically insulating coating may include polyimide and/or polytetrafluoroethylene and/or cyanate ester resin.

In one embodiment, the distribution and/or amount of the coating on both sides of the stack with respect to a horizontal symmetry plane extending through the stack is asymmetric. The horizontal symmetry plane may in fact divide the stack in two halves of the same vertical thickness. When depositing an electrically insulating coating on a dedicated stack surface, the inclined sidewalls may result in uneven coverage along the through hole in terms of coating thickness. This may have a stabilizing effect on the component carrier as a whole.

In one embodiment, the thickness of the coating at one circumferential edge between one major surface of the stack and the side wall of the stack (which may be the edge of one end of the through hole) is smaller than the larger thickness of the coating at the other circumferential edge between the opposite other major surface of the stack and the side wall of the stack (which may be the edge of the opposite end of the through hole). Specifically, the circumferential edge having a larger coating thickness may correspond to the following end of the through hole: the through-holes form an obtuse angle with the adjacent stack material at this end in a cross-sectional view. Accordingly, a circumferential edge having a smaller (e.g., zero) coating thickness may correspond to the following end of the through hole: the through-holes form an acute angle with the adjacent stack material at the end in cross-sectional view. This is shown, for example, in fig. 1. Advantageously, such an uneven coating distribution can keep the open cross-sectional area of the through-hole at its narrow end sufficiently large due to the locally smaller coating thickness at said end. This may be a great advantage especially for optical applications where light propagates through the through-hole, since the described measures may increase the functional opening size at the narrow end.

In one embodiment, one circumferential edge between one major surface of the stack and the side wall of the stack is free of coating. In particular, referring again to fig. 1, the circumferential edge with zero coating thickness may correspond to the following end of the through hole: at which end the through-hole forms an acute angle with the adjacent stack material in a cross-sectional view. Thus, the available cross-sectional area at this end may be the full area of the through hole at its narrowest location. This may be the optimal condition, especially for optical applications.

In one embodiment, the opposite other circumferential edge between the opposite other main surface of the stack and the side wall of the stack is covered by the coating. Even if the relatively thick side walls of the stack end are covered by the coating, it is acceptable without causing functional limitations, since the inclined side walls provide a very large cross-sectional area at the wide end.

In one embodiment, the taper angle between the inclined sidewall and the vertical direction perpendicular to the main surface (see angle β in fig. 1) is in the range of 0.5 ° to 20 °, for example in the range of 1 ° to 5 °. Such angles can be readily obtained by laser drilling when the wavelength, energy, irradiation duration and/or other characterizing operating parameters of the laser beam are appropriately adjusted. In particular, during laser drilling, cutting or machining, when the laser beam is placed on only one side of the stack, it is possible to produce a side wall with significant tilting characteristics by performing laser drilling.

In one embodiment, the component carrier includes a solder resist structure on one or both of the opposite major surfaces of the stack and spaced apart from the coating (where "spaced apart from the coating" may refer to the fact that the solder resist and the coating do not overlap or contact in the described embodiments). In the context of the present application, the term "solder resist structure" may particularly denote a physical structure comprising a solder resist material. In particular, such a structure may be a flat layer structure covering only a portion of the main surface of the stack. The solder resist material of such a solder resist structure may protect the stack or portions of the stack from oxidation or corrosion, in particular may protect surface portions comprising a metal such as copper. Furthermore, the solder resist may optionally define one or more surface portions of the stack of component carriers on which solder material should not and will not adhere. In short, the material of the solder resist may be selected such that the solder material does not adhere or remain on the surface area of the component carrier stack covered by the solder resist. The solder resist may also be denoted as a solder mask, and may be a thin lacquer-like layer, e.g., a thin lacquer-like layer of a polymer, that may be applied to conductive surface metals, particularly copper traces of a component carrier, such as a Printed Circuit Board (PCB), to prevent oxidation and to prevent formation of solder bridges between closely spaced solder pads. In this context, a solder bridge may be an unintended electrical connection between two electrically conductive structures through a point of solder. The solder resist can prevent solder bridging. Once applied as a continuous layer on the stack, one or more openings may be created in the solder resist in which the material should be electrically connected to the electrically conductive layer structure of the stack, for example for electrically connecting it to one or more surface mount components to solder it to the stack. Such openings may be formed by patterning a layer of continuous solder resist on the stack, for example, using photolithography. For example, a solder resist may be formed based on an epoxy liquid, which may be screen printed onto the stack through a pattern or mask. The solder resist may also be formed based on a liquid photoimageable solder resist ink, which may be applied, for example, by spraying or screen printing and may then be patterned. In addition, the solder resist may be created as a dry film photoimaged solder mask, which may be laminated and then patterned on the stack.

In an embodiment, the thickness of the solder resist structure is greater than the thickness of the coating portion on the same main surface on which the solder resist structure is provided. Advantageously, a smaller thickness of the coating in the through hole may be sufficient to reliably protect the stack surface exposed there.

In one embodiment, the material of the coating portion is ink or solder resist. When the coating portion is ink, it may, for example, provide the function of a colorant. Additionally or alternatively, it is also possible that the coating portion may be a solder resist (e.g. having the characteristics as defined above) or another solder resist structure made of another material than the solder resist structure.

Therefore, the coating portion and the solder resist structure may be different kinds of solder resists. 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, the different types 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. The different material compositions of the different types of soldermasks may result in different properties of each respective solder mask, such as strength in terms of electrical isolation, anti-adhesion properties with respect to solder, color (e.g., green, blue, black), corrosion protection, coefficient of Thermal Expansion (CTE), mechanical strength, etc. Thus, two different types of solder resist may be provided on part or the whole surface of the stack.

In one embodiment, the horizontal extension of the coating portion covering one major surface of the stack is lower than the horizontal extension of the solder resist structure on said major surface. In particular, a recess may be defined between the coating portion and the solder resist structure, more particularly such that the electrically conductive layer structure is exposed in the recess. For example, the solder resist structure may provide the function of protecting the major surfaces of the stack, while the coating may primarily create electrically insulating protection of the inner stack sidewalls. The extension of the coating to a portion of the main surface of the stack directly connected to the through hole may result in improved adhesion of the coating on the surface of the stack while also contributing to surface protection of the connected portion of the main surface. The larger thickness of the solder resist may result in reliable dielectric protection of the major surfaces from corrosion and the like compared to the coated portion, while the smaller thickness of the coated portion may keep the functional via area or volume sufficiently large.

In one embodiment, the horizontal extension of the coating portion covering one major surface of the stack is different from the other horizontal extension of the coating portion covering the opposite other major surface of the stack. By taking this measure, different areas of the two opposite main surfaces can be reflected or considered in the dielectric coating.

In one embodiment, the component carrier comprises one or more components. One or more components may be surface mounted on or embedded in the stack. In the context of the present application, the term "component" may particularly denote any bulk mass rather than a layer-type mass. The component may be an electronic component, such as an active (e.g. semiconductor chip or semiconductor package) or passive (e.g. capacitor or inductor) electronic component that has been embedded or is to be embedded inside a component carrier. However, the component may also be a non-electronic component that does not have electronic functionality. For example, the component may be a component having a thermal function, such as a heat rejection and/or heat dissipation function. For example, the component may be a metal (e.g., copper) block and/or a ceramic block.

Preferably, the at least one component may be an optical component, i.e. a component having an optical function. For example, the component carrier with the assembly may be a camera module. For example, the optical component may comprise an optical sensor. Such optical sensors may be configured to capture image data, video data, or sensor data. Additionally or alternatively, the optical component may provide an optical emitter function. Such an optical transmitter may be configured to transmit image data or video data. During operation of a component carrier having one or more optical components, photo-electromagnetic radiation (e.g., visible light, infrared light, and/or ultraviolet light) may propagate through the through-hole.

Without wishing to be bound by a particular theory, it is presently believed that the coating and solder resist on the component carrier surface may prevent so-called transient burning phenomena caused by light reflected by the exposed traces.

In one embodiment, the component carrier comprises a component, such as an optical component, at least partially received within the through-hole. Thus, at least a portion of the through-hole may be used to house at least a portion of the at least one optical component. Such an embodiment is shown, for example, in fig. 14. In a preferred example, the component is in direct contact with the electrically insulating coating.

In one embodiment, the component carrier comprises a component, such as an optical component, surface mounted on one major surface of the stack to cover the through-hole. In particular, the at least one optical component may face the through hole. Such an embodiment is shown, for example, in fig. 13. For example, the at least one photosensitive detection element and/or the at least one optical emission element of the at least one optical component may be aligned with the through-hole in the stack such that the at least one optical component mounted on the stack may functionally cooperate with and/or may emit electromagnetic radiation into the through-hole. For example, the functional fit may include alignment of the optical component with the through-hole such that the optical component is able to detect light propagating through the through-hole. Additionally or alternatively, the functional fit may include alignment of the optical component with the through hole such that the optical component is capable of emitting light propagating through the through hole.

In one embodiment, the maximum thickness of the coating on one side of the sidewall differs from the maximum thickness of the coating on the other (especially opposite) side of the sidewall by a value in the range of 1% to 20%, for example a value in the range of 2% to 10%. For example, the "thickness" of the coating on a surface portion of the sidewall may be the coating thickness perpendicular to the surface portion (e.g., perpendicular to a tangent line on the surface portion). The "maximum thickness" on the side wall side may be the maximum thickness on said side wall side between two opposite main surfaces of the stack. More precisely, the difference between the maximum thickness of the coating portion on one side of the side wall and the maximum thickness of the coating portion on the other side of the side wall on the one hand, and the absolute value of the ratio between said difference between the maximum thickness of the coating portion on one side of the side wall and the maximum thickness of the coating portion on the other side of the side wall and said maximum thickness of the coating portion on said one side of the side wall on the other hand, may be within at least one of the mentioned ranges. Thus, uniformity of sidewall coverage of the coated portion may be enhanced, as the maximum thickness variation over different sidewall portions may be limited to no more than 20%, preferably no more than 10%.

In one embodiment, the sloped sidewall tapers from one of the major surfaces toward the other of the major surfaces, with a greater amount of coating at one circumferential edge between the major surface and the sidewall, and a lesser amount of coating at the other circumferential edge between the other major surface and the sidewall. In one embodiment, the major surface may have a smaller amount of coating (e.g., mass or volume) on that major surface than the other major surface, which has a larger amount of coating on the other major surface. In short, the thickness of the coating on one circumferential edge with a larger through hole diameter may be larger than the thickness of the coating on the opposite other circumferential edge with a smaller through hole diameter (see, e.g., fig. 1).

In one embodiment, the coating covering portions of the two opposite main surfaces of the stack and the coating covering at least portions of the inclined side walls of the stack form a unitary continuous structure. The uninterrupted region may thus be protected by the coating, thereby preventing unprotected weak portions of the stack surface. Furthermore, this may promote proper adhesion between the coating and the stack.

In one embodiment, the inner opening defined by the coating portion is an inclined opening having an inclination angle with respect to the vertical direction smaller than an inclination angle of the inclined through hole with respect to the vertical direction. In particular, the internal opening defined by the coating portion may be an inclined opening having an inclination value smaller than that of the inclined through hole. In other words, the uneven sidewall coverage of the coating may at least partially compensate for the varying thickness of the through-holes between the stack sidewalls. In short, the taper at the exposed surface of the coating may be less pronounced than the side wall of the stack.

In one embodiment, the method includes applying the coating to the sidewall and to a portion of the major surface using a roller. For example, such a roller may be a cylinder that rotates about its central symmetry axis during operation (e.g. during application of the coating portion). Such rollers may be moved longitudinally along the respective major surfaces of the stack while rotating. Surprisingly, it was found that by forming the coating portion using a roller (instead of a doctor blade), an enhanced equalization of the sidewall thickness can be achieved. This can keep the center of the through hole in a consistent position before and after coating. However, alternative methods of forming the coating portion are also possible, such as spraying, screen printing, and the like.

In one embodiment, the method includes applying the coating on the side walls and on portions of the major surfaces using pairs of rollers that roll along opposite major surfaces of the stack, preferably using pairs of rollers that roll simultaneously along opposite major surfaces of the stack (which may all be implemented as described above for rollers). By taking such measures, excellent coating portion accuracy and high accuracy characteristics of the coated through-hole can be achieved.

In an embodiment, the stack of component carriers 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 and electrically conducting layer structure, in particular a laminate formed by applying mechanical pressure and/or thermal energy. The mentioned stack may provide a plate-like component carrier that is capable of providing a large area mounting surface for more components and that is in any case very thin and compact.

In one embodiment, the component carrier is formed as a plate. This contributes to a compact design, wherein the component carrier still provides a large basis for mounting the component on the component carrier. In addition, particularly as a bare wafer of an embedded electronic component, for example, since the thickness of the bare wafer of the embedded electronic component is small, it can be conveniently embedded in a thin plate member such as a printed circuit board.

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

In the context of the present application, the term "printed circuit board" (PCB) may particularly denote a plate-like component carrier formed by laminating a plurality of electrically conductive layer structures with a plurality of electrically insulating layer structures, for example by applying pressure and/or providing thermal energy. As a preferred material for PCB technology, the electrically conductive layer structure is made of copper, whereas the electrically insulating layer structure may comprise resin and/or glass fibers, a material known as prepreg or FR 4. The various electrically conductive layer structures may be connected to each other in a desired manner by: the via or any other via connection is formed by forming a hole through the laminate, for example by laser drilling or mechanical drilling, and by filling the hole partially or completely with an electrically conductive material, in particular copper. A fill hole connects the entire stack (a via connector extends through several layers or the entire stack), or a fill hole connects at least two electrically conductive layers, said fill hole being called a via. Similarly, to receive an electro-optic circuit board (EOCB), optical interconnects may be formed by the various layers of the stack. In addition to one or more components that may be embedded in a printed circuit board, the printed circuit board is typically configured to house one or more components on one or both opposing surfaces of the board-like printed circuit board. The one or more components may be attached to the respective major surfaces by welding. The dielectric portion of the PCB may be composed of a resin with reinforcing fibers (e.g., glass fibers).

In the context of the present application, the term "substrate" may particularly denote a small component carrier. The substrate may be a relatively small component carrier associated with the PCB on which one or more components may be mounted and which may act as a connection medium between one or more chips and the further PCB. For example, the substrate may have substantially the same dimensions as the component (in particular, the electronic component) to be mounted thereon (e.g., in the case of a Chip Scale Package (CSP)). In another embodiment, the substrate may be substantially larger than the designated component (e.g., a Flip Chip Ball Grid Array (FCBGA) configuration). More particularly, a substrate may be understood as a carrier of an electrical connection or grid and a component carrier compared to a Printed Circuit Board (PCB), however, a substrate has a rather high density of laterally and/or longitudinally arranged connections. The transverse connection is for example a conductive path, while the longitudinal connection may be for example a borehole. These cross-connectors and/or vertical connectors are arranged within the substrate and may be used to provide electrical, thermal and/or mechanical connection of a cased component or caseless component (e.g. a bare die) of an IC chip, in particular, to a printed circuit board or an intermediate printed circuit board. Thus, the term "substrate" also includes "IC substrate". The dielectric portion of the substrate may be composed of a resin with reinforcing particles (e.g., reinforcing spheres, particularly glass spheres).

The substrate or interposer may include or consist of at least the following layers: glass, silicon (Si) and/or photoimageable or dry etchable organic materials, such as epoxy-based build-up materials (e.g., epoxy-based build-up films), or polymeric compounds such as polyimides or polybenzoxazoles (which may or may not contain photo and/or thermo-sensitive molecules).

In an embodiment, the at least one electrically insulating layer structure comprises at least one of: resins or polymers such as epoxy resins, cyanate resins, benzocyclobutene resins, bismaleimide-triazine resins, polyphenylene derivatives (e.g., based on polyphenylene ether, PPE), polyimides (PI), polyamides (PA), liquid Crystal Polymers (LCP), polytetrafluoroethylene (PTFE), and/or combinations thereof. Reinforcing structures may also be used, such as: a mesh, fiber, sphere or other type of filler particles, for example made of glass (multiple layer glass), to form the composition. The semi-cured resin is combined with reinforcing agents, such as fibers impregnated with the resins described above, and is referred to as a prepreg. These prepregs are often named for their properties, for example: FR4 or FR5, which describe their flame retardant properties. While prepregs, particularly FR4, are generally preferred to be rigid PCBs, other materials, particularly epoxy-based buildup materials (e.g., buildup films) or photoimageable dielectric materials, may also be used. For high frequency applications, high frequency materials such as polytetrafluoroethylene, liquid crystal polymers, and/or cyanate resins may be preferred. In addition to these polymers, low temperature co-fired ceramics (LTCC) or other low, very low, extremely low DK materials may be applied as an electrically insulating structure in the component carrier.

In an embodiment, the at least one electrically conductive layer structure comprises at least one of: copper, aluminum, nickel, silver, gold, palladium, tungsten, magnesium, carbon, (especially doped) silicon, titanium and platinum. While copper is generally the preferred material, other materials or coated versions thereof are also possible, particularly materials coated with superconducting or conducting polymers, such as graphene or poly (3, 4-ethylenedioxythiophene) (PEDOT), respectively.

At least one component may be embedded in the stack and/or surface mounted on the stack. The component and/or at least one other component may be selected from: an electrically non-conductive inlay, an electrically conductive inlay (such as a metal inlay, preferably comprising copper or aluminum), a heat transfer unit (e.g., a heat pipe), a light guiding element (e.g., an optical waveguide or a light conductor connection), an electronic component, or a combination of the foregoing. The inlay may be, for example, a metal block with or without an insulating material coating (IMS-in), which may be embedded or surface mounted to facilitate heat dissipation. The appropriate material is determined based on the thermal conductivity of the material, which should be at least 2W/mK. Such materials are typically based on, but are not limited to, metals, metal oxides, and/or ceramics, such as copper, aluminum oxide (Al ₂O₃), or aluminum nitride (AlN). Other geometries with increased surface area are also often used in order to increase heat exchange capacity. Furthermore, the components may be active electronic components (implementing at least one p-n junction), passive electronic components such as resistors, inductors, or capacitors, electronic chips, memory devices (e.g., DRAM or other data storage device), filters, integrated circuits (e.g., field Programmable Gate Array (FPGA), programmable Array Logic (PAL), general purpose array logic (GAL), and Complex Programmable Logic Devices (CPLD)), signal processing components, power management components (e.g., field Effect Transistors (FETs), metal Oxide Semiconductor Field Effect Transistors (MOSFETs), complementary Metal Oxide Semiconductors (CMOS), junction Field Effect Transistors (JFETs) or Insulated Gate Field Effect Transistors (IGFETs), all based on semiconductor materials such as silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), gallium oxide (Ga ₂O₃), indium arsenide (InGaAs), indium phosphide (InP) and/or any other suitable inorganic compound), photovoltaic interface elements, light emitting diodes, photocouplers, voltage converters (e.g., DC/DC converters or AC/DC converters), encryption components, and receivers, electromechanical transducers, switches, micro-electromechanical transducers, switches, capacitors, charge-trapping devices, micro-electromechanical systems, and power converters, micro-processors, and power converters. However, other components may be embedded in the component carrier. For example, a magnetic element may be used as the member. Such magnetic elements may be permanent magnetic elements (e.g. ferromagnetic elements, antiferromagnetic elements, multiferroic elements or ferrimagnetic elements, such as ferrite cores) or may be paramagnetic elements. However, the component may also be an IC substrate, interposer or another 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 within the component carrier. In addition, other components, particularly those that generate or emit electromagnetic radiation and/or are sensitive to electromagnetic radiation propagating from the environment, may also be used as components.

In one embodiment, the component carrier resulting from the component carrier structure is a laminate type component carrier. In this embodiment, the component carrier is a composite of a multi-layer structure that is stacked or joined together by the application of pressure and/or heat.

After the treatment of the component carrier inner layer structure, one or both opposite main surfaces of the treated layer structure may be covered in a symmetrical or asymmetrical manner, in particular by lamination, with one or more further electrically insulating layer structures and/or electrically conductive layer structures. In other words, stacking may continue until a desired number of layers are obtained.

After the formation of the stack of electrically insulating layer structures and electrically conductive layer structures is completed, the surface treatment of the resulting layer structure or component carrier may be continued.

In particular, in terms of surface treatment, an electrically insulating solder resist may be applied to one or both opposite major surfaces of the layer stack or component carrier. For example, such a solder resist may be formed over the entire major surface and then the solder resist layer patterned so as to expose one or more electrically conductive surface portions that should be used to electrically couple the component carrier to the electronic periphery. The surface portion of the component carrier that remains coated with the solder resist can be effectively prevented from oxidation or corrosion, especially the surface portion containing copper.

For surface treatment, the surface treatment may also be applied selectively to the exposed electrically conductive surface portions of the component carrier. Such surface treatments may be electrically conductive coating material on electrically conductive layer structures (e.g. pads, conductive traces, etc., particularly comprising or consisting of copper) exposed on the surface of the component carrier. If these exposed electrically conductive layer structures are not protected, the exposed electrically conductive component carrier material (particularly copper) may oxidize, which may make the component carrier less reliable. The surface finish may then be formed, for example, as an interface between a surface mount component and a component carrier. The surface finish has the function of protecting the exposed electrically conductive layer structure, in particular the copper circuit, and enables a process of connecting one or more components, for example by soldering. Examples of suitable materials for the surface treatment are: organic Solderability Preservative (OSP), electroless nickel deposit (ENIG), electroless nickel deposit palladium deposit (ENIPIG), electroless nickel electroless palladium deposit (ENEPIG), gold (especially hard gold), electroless tin (electroless and electroplating), nickel gold, nickel palladium, and the like. Nickel-free materials may also be applied to the surface finish, particularly for high speed applications. For example ISIG (silver deposited gold) and EPAG (electroless palladium autocatalytic gold).

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 the examples of embodiment.

Drawings

Fig. 1 shows a cross-sectional view of a component carrier according to an exemplary embodiment of the invention.

Fig. 2 shows an image of a component carrier according to an exemplary embodiment of the invention.

Fig. 3 to 7 show different views of a structure obtained during execution of the method of manufacturing the component carrier shown in fig. 7 according to an exemplary embodiment of the present invention.

Fig. 8 to 12 illustrate structures obtained during manufacturing of the component carrier illustrated in fig. 12 according to exemplary embodiments of the present invention.

Fig. 13 shows a cross-sectional view of a component carrier according to an exemplary embodiment of the invention.

Fig. 14 shows a cross-sectional view of a component carrier according to another exemplary embodiment of the invention.

Detailed Description

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

Before the exemplary embodiments are described in further detail with reference to the accompanying drawings, some basic considerations upon which the exemplary embodiments of the present invention were developed will be summarized.

In conventional methods of forming ink-type coatings on the sidewalls of stacks defining through-holes of component carriers, the ink thickness on the cavity sidewalls may be highly unbalanced. As a result, the cavity center position may become unstable during coating, i.e., it may not be consistent before coating and after coating. The reference cavity center to copper pad distance may also be unstable. Thus, conventional methods do not produce uniform sidewall thickness, which can result in movement of the center of the cavity after coating. Traditionally, the cavity center to pad distance may not be controlled with sufficiently small tolerances. In conventional approaches, sidewall coating on the through holes of the component carrier stack may be very uncontrolled and unsatisfactory.

According to an exemplary embodiment of the invention, a component carrier (e.g. of the printed circuit board type) having a (e.g. laminated) layer stack is provided with at least substantially vertical through holes extending between the front side and the rear side of the stack. Although the through-holes extend substantially vertically through the stack, the lateral side walls of the through-holes that provide an interface with the circumferential stack material may be slanted or angled instead of extending vertically. For example, the through hole may have a truncated cone shape. Such a shape may be produced, for example, by laser drilling with correspondingly adjusted operating parameters. In addition, the electrically insulating coating may be deposited on a surface portion of the stack comprising a portion of the opposite major surface and the inclined side wall or a portion thereof. For example, the coating or liner may provide a solder resist function to provide chemical and/or mechanical protection. The through-holes defined by the inclined side walls may provide advantageous properties for components to be mounted on the main surface of the stack having functional access to the through-holes and/or components (in particular optical components) to be mounted at least partly in the through-holes. Preferably, the component may be in direct contact with the electrically insulating coating, in particular, the component may be positioned on the inclined side wall and optionally on one main surface of the stack. Advantageously, the architecture described may enable more or even highly uniform sidewall thickness of the stack coating in the through-hole to be obtained, avoiding excessive center-shifting due to the coating.

In particular, exemplary embodiments provide a method of applying ink to cavities in a stack of component carriers. In such embodiments, the coating or ink thickness on the chamber sidewalls may be uniform. Specifically, the left-right sidewall thickness gap may be reduced to less than 20 μm. Furthermore, the through center or cavity center position may remain substantially uniform (e.g., offset may be less than 10 μm) before coating and after coating. In particular, the distance of the cavity center to the metal reference pad (e.g., copper pad) may be stable, and the tolerance may be controlled within a range of, for example, 25 μm or less. Thus, a uniform sidewall thickness can be obtained, which can keep the cavity (or through hole) center in a uniform position before coating and after coating. Thus, the distance from the center of the cavity to the pad can be controlled within a small tolerance.

The mentioned and/or other advantages may be particularly apparent when the component carrier with components mounted in alignment with the coated through holes is implemented as a camera module.

Fig. 1 shows a cross-sectional view of a component carrier 100 according to an exemplary embodiment of the invention. In the illustrated embodiment, the component carrier 100 is implemented as a Printed Circuit Board (PCB). However, the component carrier 100 may also be an Integrated Circuit (IC) substrate or the like.

The component carrier 100 according to fig. 1 comprises a stack 102, the stack 102 comprising a plurality of electrically conductive layer structures 104 and a plurality of electrically insulating layer structures 106. The stack 102 of fig. 1 may include layers and vias (not shown) in a stacked configuration. It is particularly possible that the stack 102 is provided with a core in a layer stack.

The electrically conductive layer structure 104 may include a patterned copper layer that may form horizontal pads and/or horizontal wiring structures. Additionally, the electrically conductive layer structure 104 may include vertical through-connections, such as copper pillars and/or copper filled laser vias. Additionally or alternatively, mechanical Plated Through Holes (PTHs) may also be used as vertical through connections. Further, the stack 102 of component carriers 100 may include one or more electrically insulating layer structures 106 (e.g., one or more prepreg sheets, resin sheets, or cores made of FR4 material). A flavoured laminated film (ABF) material may also be used for at least a portion of the electrically insulating layer structure 106, in particular when the component carrier 100 is implemented as an IC substrate. In addition, a surface treatment (e.g., ENIG or ENEPIG, etc.) may optionally be applied on the top and/or bottom sides of stack 102 (not shown).

As shown in fig. 1, a through hole 108 is formed in the stack 102 and extends vertically through the entire stack 102. When the through-hole 108 is formed by laser drilling or laser cutting with appropriate laser parameters (e.g. 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 fig. 1 only), the through-hole 108 may be defined by the inclined side walls 110 of the stack 102 and the through-hole 108 is located between the inclined side walls 110 of the stack 102, resulting in a tapered through-hole 108. The inclined (rather than vertical) side wall 110 of the stack 102 comprises an angle β+note0with respect to a vertical direction 130 perpendicular to the opposite horizontal major surfaces 114, 116 of the stack 102. According to fig. 1, the through hole 108 has a substantially frustoconical shape.

Still referring to fig. 1, the electrically insulating coating 112 may be formed to cover a portion of the two opposite major surfaces 114, 116 of the stack 102 and the entire inclined sidewall 110 of the stack 102. More specifically, the electrically insulating coating 112 is disposed throughout the sidewall 110 defining the through-hole 108, and the electrically insulating coating 112 is also disposed at a respective annular portion of each major surface 114, 116 immediately surrounding the through-hole 108 at both ends. The peripheral edge 120 between the sidewall 110 and the major surface 114 (where the sidewall 110 and the peripheral edge 120 include an acute angle (rather than an obtuse angle)), the peripheral edge 120 may remain uncovered by the electrically insulating coating 112, i.e., the peripheral edge 120 may be partially exposed. The horizontal extension L of the coating portion 112 covering one major surface 114 of the stack 102 may be different from the other horizontal extension L of the coating portion 112 covering the opposite other major surface 116 of the stack 102. The inner opening of the through-hole 108, which is now limited in size by the coating portion 112, may be an inclined opening having an inclination angle epsilon with respect to the vertical direction 130, which inclination angle epsilon with respect to the vertical direction 130 is smaller than the inclination angle beta of the side wall 110 with respect to the vertical direction 130.

For example, the electrically insulating coating 112 may be ink or solder resist. The ink may include a colorant for providing the electrically insulating coating 112 with a defined color. The solder resist may protect the covered surface of the stack 102, e.g., from corrosion or oxidation, for ensuring dielectric isolation, for providing mechanical protection, etc.

As shown in fig. 1, the distribution and amount (in terms of volume and mass) of the coating 112 on both sides of the stack 102 relative to a horizontal symmetry plane 118 extending centrally through the stack 102 is asymmetric. Thus, different amounts of ink or coating 112 may be present on portions of the surface of the stack 102 above and below the horizontal plane of symmetry 118. More precisely, the amount of coating 112 below the horizontal symmetry plane 118 may be greater than the amount of coating 112 above the horizontal symmetry plane 118. Accordingly, there may be a greater mass or volume of coating 112 on the other half of the stack 102 corresponding to a greater angle between the major surface 116 and the sidewall 110 than the half of the stack 102 corresponding to a lesser angle between the major surface 114 and the sidewall 110.

The illustrated distribution of the material of the coating 112 within and around the through-hole 108 keeps a substantial portion of the interior volume of the through-hole 108 unfilled or empty. Said unfilled or empty volume of the through-hole 108 may then be used as a functional volume for applications, in particular for optical applications (see fig. 13 and 14). This allows improved functionality and/or reduced space consumption for forming the component carrier 100.

Referring again to fig. 1, the coating portion 112 may have a smaller thickness D at one circumferential edge 120 between the major surface 114 of the stack 102 and the side wall 110 of the stack 102 than the larger thickness D of the coating portion 112 at the opposite other circumferential edge 122 between the opposite other major surface 116 of the stack 102 and the side wall 110 of the stack 102. As shown, in the illustrated embodiment, the thickness d=0, while in other embodiments, the equation D > d+note0may be satisfied (see fig. 12). However, in the embodiment of fig. 1, the circumferential edge 120 between the main surface 114 of the stack 102 and the side wall 110 of the stack 102 is free of the coating 112 (d=0), while the opposite other circumferential edge 122 between the opposite other main surface 116 of the stack 102 and the side wall 110 of the stack 102 is covered by the coating 112 (D > 0). This configuration has the following advantages: since the sloped side walls 110 of the stack 102 define the through-holes 108, the surface area of the stack defining the through-holes 108 and covered by the electrically insulating coating 112 may be increased compared to vertical side walls. The increased surface coverage of the coating portion 112 may positively affect adhesion. Meanwhile, where the diameter of the through hole 108 is smallest, i.e., at the upper main surface 114, the thickness of the coating portion is locally reduced. This keeps the functional aperture opening large while ensuring proper mechanical integrity of the component carrier 100.

For example, the taper angle β between the sloped sidewall 110 and the vertical direction 130 perpendicular to the major surfaces 114, 116 may be in the range of 1 ° to 5 °. Alternatively, the taper angle β between the inclined sidewall 110 and the vertical direction 130 perpendicular to the main surfaces 114, 116 may be in the range of 6 ° to 45 °. The taper angle β may also vary around the perimeter of the through hole 108, for example, in view of the slight inclination of the drilling or cutting laser beam relative to the major surfaces 114, 116, the spatial energy variation of the drilling or cutting laser beam.

In another example, the electrically insulating coating 112 may have a concave portion (as seen in fig. 1). Alternatively, the electrically insulating coating 112 may have a convex portion. This may increase the surface area towards the through hole 108 and may thus enable a reliable mechanical interaction with the component 126.

As also shown in fig. 1, solder resist structures 124 may be applied to opposite major surfaces 114, 116 of stack 102 in areas other than coating 112. Also, the coating portion 112 may be implemented as another solder resist structure and the coating portion 112 may be made of another material different from the solder resist structure 124 (or may be made of the same material as the solder resist structure 124). This may allow for individual and separate adjustment of the local solder resist characteristics of the component carrier 100 when the materials of the solder resist structure 124 and the solder resist coating 112 are different from each other. In the illustrated embodiment, the thickness B of the solder resist 124 on a respective one of the major surfaces 114, 116 is greater than the thickness B of the coating 112 on the same major surface 114, 116, respectively. Alternatively, the thickness B of the solder resist structure 124 on the respective one of the major surfaces 114, 116 may be less than the thickness B of the coating 112 on the same major surface 114, 116, respectively. Furthermore, the horizontal extension of the coating 112 on a respective one of the main surfaces 114, 116 of the cover stack 102 is lower than the horizontal extension of the solder resist structure 124 on said respective main surface 114, 116. Alternatively, the horizontal extension of the coating 112 covering a respective one of the main surfaces 114, 116 of the stack 102 may be higher than the horizontal extension of the solder resist structure 124 on said respective main surface 114, 116.

Preferably, a lateral recess may be formed between the coating portion 112 and the solder resist structure 124 on the respective major surfaces of the major surfaces 114, 116 such that the coating portion 112 and the solder resist structure 124 do not overlap or contact in the lateral direction. This may allow for exposure of the electrically conductive layer structure 104, such as a pad (e.g., copper pad), which electrically conductive layer structure 104 is exposed in the recess between the solder resist coating 112 and the solder resist structure 124 for connection purposes. Another electrically conductive layer structure 104, such as another pad or wiring structure (e.g., another copper pad or copper wiring structure), on a respective one of the major surfaces 114, 116 may be covered by a solder resist structure 124 for protection purposes. Although not shown, the coating portion 112 and the solder resist 124 may also overlap or contact each other.

Advantageously, the maximum thickness H of the coating portion 112 on one side of the side wall 110 and the maximum thickness H of the coating portion 112 on the other side of the side wall 110 may differ by a value preferably ranging from 2% to 10% (in particular, the absolute value of (H-H)/H may range from 2% to 10%). Therefore, the uniformity of the coating portion 112 covering the sidewall may be higher than that in the conventional method. This can positively affect the mechanical integrity of the component carrier 100, so that undesirable phenomena such as warpage and delamination can be suppressed. Due to the high uniformity of the coating 112 to sidewall coverage, there may also be no or no significant spatial offset in the center of the through hole 108 due to the deposition of the coating 112 compared to the situation prior to the deposition.

As shown, the sloped sidewall 110 tapers from the main surface 116 toward the other main surface 114, with a greater amount of coating 112 at one circumferential edge 122 between the main surface 116 and the sidewall 110, and a lesser amount of coating 112 at the other circumferential edge 120 between the other main surface 114 and the sidewall 110.

Fig. 2 shows an image of a component carrier 100 according to an exemplary embodiment of the invention. Many of the parameters and attributes described with reference to fig. 1 can also be seen in fig. 2. In this embodiment, the value of D may be zero or nearly zero.

Fig. 3 to 7 show different views of a structure obtained during execution of a method of manufacturing the component carrier 100 shown in fig. 7 according to an exemplary embodiment of the present invention.

Referring to the three-dimensional view of fig. 3, a laminate layer stack 102 is shown, which laminate layer stack 102 may include an electrically conductive layer structure 104 and an electrically insulating layer structure 106 (not shown), which may be implemented as described with reference to fig. 1. Holes 108 have been formed in the stack 102 by laser drilling or laser cutting to define sloped sidewalls 110 of the stack 102. In addition, solder resist structures 124 have been applied and patterned on a portion of major surface 114 of stack 102.

With reference to fig. 4 (showing a plan view) and fig. 5 (showing a side view), a process of covering a surface portion of the component carrier preform of fig. 3 will be explained. As also shown in fig. 6, the ink-type or solder-resist type coating 112 can be applied during coating application using rollers 128 that move in a combined longitudinal and rotational motion as indicated by arrows 150 over the entire sidewall 110 and over the directly connected portions of the major surfaces 114, 116. During the application of the material of the coating 112 to the sidewall 110 and to the joining portions of the major surfaces 114, 116, a pair of rollers 128 may be used that roll along the opposite major surfaces 114, 116 of the stack 102. Preferably, the rollers 128 are simultaneously rolled along the opposite major surfaces 114, 116 of the stack 102. By taking this measure, the material of the coating portion 112 may be uniformly applied to substantially the entire inclined side wall of the stack 102 defining the through hole 108. The uniformity of the sidewall coverage of the resulting coated portion 112 may be significantly improved by simultaneously applying the application of the rollers 128 on the opposite major surfaces 114, 116 of the stack 102 to arrange (line) the sidewalls 110 defining the inclined through-holes 108, as compared to conventional methods of applying the coated portion, for example, using a doctor blade.

Referring to fig. 6, the result of the described uniform application of the coating 112 to the inclined side wall 110 of the stack 102 is shown. More precisely, the result of the described manufacturing method is the formation of an electrically insulating coating 112 on annular portions of the two opposite main surfaces 114, 116 of the stack 102 and on the entire surface area of the inclined side walls 110 of the stack 102.

However, alternative methods of forming the coating portion (as compared to fig. 4 and 5) are also possible, such as spraying, screen printing, etc.

Referring to fig. 7, characteristics of the obtained component carrier 100 are shown. In general, the described fabrication methods may allow for uniform sidewall thickness to be produced, which may maintain uniform cavity centers before and after coating. Furthermore, this may allow for control of the cavity center to pad distance with small tolerances.

As shown, the thickness of the chamber sidewalls may be uniform such that the difference between the left sidewall thickness 152 and the right sidewall thickness 154 may be less than 20 μm.

Also as shown, the cavity center position can be consistent before coating and after coating, with a shift of less than 10 μm. Fig. 7 shows the cavity center after coating with reference numeral 156 and the cavity center before coating with reference numeral 158.

Referring now to reference numeral 160 in fig. 7, the distance of the cavity center relative to the pad (see electrically conductive layer structure 104 on the top side) may remain stable and the tolerance may be controlled to within 25 μm or less. In one embodiment, not the entire sidewall 110 of the via 108 must be sloped, but rather portions of the sidewall 110 may be vertical.

Fig. 8 to 12 illustrate structures obtained during manufacturing of the component carrier 100 illustrated in fig. 12 according to exemplary embodiments of the present invention.

As shown in fig. 8, a three-dimensional view of the stack 102 (which may be constructed as described above with reference to fig. 1) is shown, wherein the patterned solder resist structure 124 covers a portion of a major surface of the stack 102.

As shown in fig. 9, a via 108 may be formed in the stack 102 by laser processing, the via 108 being defined by sloped sidewalls 110.

Fig. 10 shows a sectional view corresponding to fig. 8. Fig. 11 shows a sectional view corresponding to fig. 9.

As shown in fig. 12, the coating 112 may then be applied to the entire sidewall 110 and portions of the major surfaces 114, 116. Thus, a structure similar to that of fig. 1 can be obtained. Because of the taper 162, the top cavity diameter 164 may be greater than the bottom cavity diameter 166. However, this difference is partially compensated by the larger thickness D > d+.0 at the top chamber diameter 164, compared to the smaller thickness D at the bottom chamber 166. As shown, the coating 112 covering a portion of the two opposite major surfaces 114, 116 of the stack 102 and the coating 112 covering a portion of the inclined side wall 110 of the stack 102 form a unitary continuous structure. This may improve the mechanical integrity of the component carrier 100.

Fig. 13 shows a cross-sectional view of a component carrier 100 according to an exemplary embodiment of the invention.

According to fig. 13, the component carrier 100 comprises a surface mounted optical component 126. For example, the component 126 may include a photosensitive camera element 170, the photosensitive camera element 170 configured to capture optical data corresponding to light propagating through the through-hole 108. The component 126 may include electrically conductive pads 172, which electrically conductive pads 172 may be electrically coupled to pads corresponding to the electrically conductive layer structures 104 exposed on the major surface 116 of the stack 102. For example, electrical coupling may be achieved through solder structures 174. The optical component 126 surface mounted on the major surface 116 of the stack 102 may face the through-hole 108 and may be aligned with the through-hole 108 to enable optical communication between the photosensitive camera element 170 of the hole 108 and a side of the stack 102 facing away from the component 126. Electromagnetic radiation, such as light 178, may propagate through the through-hole 108 toward the photosensitive camera element 170 of the component 126 for optical detection. Signals related to the detected information may be transmitted from the component 126 to the stack 102 via electrically conductive pads 172, the electrically conductive pads 172 being electrically coupled to pads corresponding to the electrically conductive layer structures 104 exposed on the major surface 116 of the stack 102.

However, other ways of establishing an electrical connection are possible besides connecting the electrically conductive pads 172 with pads corresponding to the electrically conductive layer structure 104 by solder, sintering, or conductive glue. For example, electrically conductive pads 172 may be connected to pads corresponding to electrically conductive layer structure 104 by wire bonding (e.g., using bond wires or bond straps). Holders may also be used for this purpose. Wire or clip bonding may also allow coupling of electrically conductive pads 172 with pads corresponding to electrically conductive layer structures 104 arranged side-by-side (e.g., at the same vertical level).

Fig. 14 shows 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. An optical component 126 may be received within the through-hole 108.

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. Elements described in association with different embodiments may also be combined.

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

The implementation of the invention is not limited to the preferred embodiments shown in the drawings and described above. On the contrary, many variations are possible using the shown solution and according to the principles of the invention, even in the case of radically different embodiments.

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 defining an inclined side wall (110) of the stack (102); and

An electrically insulating coating (112) covering portions of the two opposite main surfaces of the stack (102) and at least a portion of the inclined side wall (110) of the stack (102), for example covering portions of the two opposite main surfaces of the stack (102) and the entire inclined side wall (110) of the stack (102).

2. Component carrier (100) according to claim 1, wherein the coating (112) is asymmetric in distribution and/or amount on both sides of the stack (102) with respect to a horizontal symmetry plane (118) extending through the stack (102).

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

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

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

6. The component carrier (100) according to any one of claims 1 to 5, wherein a taper angle (β) between the inclined side wall (110) and a vertical direction (130) perpendicular to the main surface is in the range of 0.5 ° to 20 °, e.g. a taper angle (β) between the inclined side wall (110) and a vertical direction (130) perpendicular to the main surface is in the range of 1 ° to 5 °.

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

8. The component carrier (100) according to claim 7, wherein the solder resist structure (124) has a thickness that is greater than a thickness of the coating (112) on the same main surface on which 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. Component carrier (100) according to any one of claims 7 to 9, wherein a horizontal extension of the coating portion (112) covering one main surface of the stack (102) is lower than a horizontal extension of the solder resist structure (124) on the main surface, in particular such that a recess is defined between the coating portion (112) and the solder resist structure (124), more in particular such that an electrically conductive layer structure (104) is exposed in the recess.

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

12. The component carrier (100) according to any one of claims 1 to 11, wherein the component carrier (100) comprises a component (126) at least partially accommodated within the through hole (108), e.g. the component (126) is an optical component.

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

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

15. The component carrier (100) according to any one of claims 1 to 14, wherein a maximum thickness of the coating portion (112) on one side of the inclined side wall (110) differs from a maximum thickness of the coating portion (112) on the other side of the inclined side wall (110) by a value in the range of 1% to 20%, e.g. a maximum thickness of the coating portion (112) on one side of the inclined side wall (110) differs from a maximum thickness of the coating portion (112) on the other side of the inclined side wall (110) by a value in the range of 2% to 10%.

16. The component carrier (100) according to any one of claims 1 to 15, wherein the inclined side walls (110) taper from one of the main surfaces (116) towards the other of the main surfaces (114), with a larger number of coating portions (112) at one circumferential edge (122) between the main surfaces (116) and the inclined side walls (110) and a smaller number of coating portions (112) at the other circumferential edge (120) between the other main surface (114) and the inclined side walls (110).

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

18. The component carrier (100) according to any one of claims 1 to 17, wherein the coating (112) covering portions of two opposite main surfaces of the stack (102) and the coating (112) covering at least portions of the inclined side walls (110) of the stack (102) form a unitary continuous structure.

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

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), the through hole defining an inclined sidewall (110) of the stack (102); and

An electrically insulating coating (112) is formed on portions of the two opposite main surfaces of the stack (102) and on at least part of the inclined side walls (110), for example, an electrically insulating coating (112) is formed on portions of the two opposite main surfaces of the stack (102) and on the entire inclined side walls (110) of the stack (102).

21. The method of 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 inclined side wall (110) and on a portion of the main surface using a roller (128).

23. The method according to claim 20 or 21, wherein the method comprises applying the coating portion (112) on the inclined side wall (110) and on a portion of the main surface using a pair of rollers (128) rolling along opposite main surfaces of the stack (102), preferably applying the coating portion (112) on the inclined side wall (110) and on a portion of the main surface using rollers (128) rolling simultaneously along opposite main surfaces of the stack (102).