Electronic board and method for manufacturing the same

Abstract

An electronic board includes: a stack including at least one electrically insulating layer structure and a plurality of electrically conductive layer structures, where one of the plurality of electrically conductive layer structures is disposed on one major surface of the at least one electrically insulating layer structure, and the other of the plurality of electrically conductive layer structures is disposed on the other major surface of the at least one electrically insulating layer structure; and another electrically conductive layer structure of the plurality of electrically conductive layer structures is disposed on another opposite major surface of the at least one electrically insulating layer structure; a via formed in the stack and laterally delimited by a conductive material; at least one plating layer disposed on at least portions of the two opposite major surfaces of the stack and on the sidewalls of the stack; an axial annular projection disposed at one end of the through hole; and a radial annular projection disposed at a sidewall of the stack. The invention also provides a method for manufacturing the electronic board.

Description

Technical Field

[0001] This invention relates to electronic boards and methods for manufacturing such electronic boards. Background Technology

[0002] As the functionality of electronic boards continues to grow and the miniaturization of such boards, such as printed circuit boards, increases, increasingly robust packages are being adopted. These packages have multiple contacts or connections with increasingly smaller spacing between them. In particular, electronic boards must be mechanically robust and electrically reliable so that they can operate even under harsh conditions.

[0003] Conventional methods for forming electronic boards remain challenging. Summary of the Invention

[0004] It may be necessary to form a compact and reliable electronic board.

[0005] According to an exemplary embodiment of the present invention, an electronic board is provided, comprising: a stack, the stack including at least one electrically insulating layer structure and a plurality of electrically conductive layer structures, one of the plurality of electrically conductive layer structures being disposed on a main surface of the at least one electrically insulating layer structure, and another of the plurality of electrically conductive layer structures being disposed on an opposite main surface of the at least one electrically insulating layer structure; a through hole formed in the stack and laterally defined by an electrically conductive material; at least one plating layer disposed on at least a portion of the two opposite main surfaces of the stack and on a sidewall of the stack; an axial annular protrusion disposed at one end of the through hole; and a radial annular protrusion disposed on a sidewall of the stack.

[0006] According to another exemplary embodiment of the present invention, a method for manufacturing an electronic board is provided, wherein the method includes: providing a stack comprising at least one electrically insulating layer structure and a plurality of electrically conductive layer structures, wherein one of the plurality of electrically conductive layer structures is disposed on a main surface of the at least one electrically insulating layer structure, and another of the plurality of electrically conductive layer structures is disposed on an opposite main surface of the at least one electrically insulating layer structure; forming a through hole in the stack; forming at least one plating layer on at least a portion of the two opposite main surfaces of the stack and on a sidewall of the stack; forming an axial annular protrusion at one end of the through hole; and forming a radial annular protrusion at the sidewall of the stack.

[0007] In the context of this application, the term "electronic board" can specifically refer to any support structure with electrical functions. For example, the electronic board can be a printed circuit board (PCB), etc. A printed circuit board can be a simple layered stack and does not necessarily need to support any components. However, an electronic board can also be a component carrier. More generally, an electronic board or PCB can also be an interposer or an IC (integrated circuit) substrate. An electronic board may be able to house one or more components thereon and / or therein to provide mechanical support and / or electrical and / or thermal connections, or it may not house one or more components thereon and / or therein. In other words, an electronic board can be constructed as a mechanical board and / or an electronic board and / or a thermal board, for example, but not necessarily as a component carrier. An electronic board can include laminated stacks, such as laminated layered stacks. In particular, an electronic board can be one of a printed circuit board, an organic interposer, and an IC (integrated circuit) substrate. An electronic board can also be a hybrid board combining the above-mentioned different types of electronic boards. An electronic board can be flat or plate-shaped.

[0008] In the context of this application, the term "stack" may specifically refer to a planar or planar sheet-like body. For example, the stack may be a layered stack, particularly a laminated or calendered layered stack. Such a laminate can be formed by applying mechanical pressure and / or heat to join multiple layers together. Preferably, the multiple layers are arranged in parallel to each other. The electrical stack may include an electrically conductive structure and at least one electrically insulating structure.

[0009] In the context of this application, the term "layer structure" may specifically refer to a continuous layer, a patterned layer, or more discontinuous islands within a common plane that can perform electrical conductivity and / or electrical insulation functions. A layer structure may also include interconnect structures protruding from the plane of the layer structure.

[0010] In the context of this application, the term "through-hole" may specifically refer to a hollow volume portion extending a complete path between two opposite main surfaces of a stack. For example, a through-hole may be a single vertical through-hole or a single inclined through-hole. The through-hole may also consist of multiple connected sub-sections. For example, the through-hole may have a cross-section with vertical sidewalls, a gradually tapering cross-section, or an hourglass-shaped cross-section (i.e., a cross-section formed by two connected sub-sections tapering in opposite directions). The through-hole may be filled with a paste material, particularly including an electrically insulating material. However, the through-hole may also be empty or hollow. A through-hole through the stack may be a through-hole that runs the entire length of the electronic board, or it may be part of a blind via forming the electronic board. Axial and / or radial annular protrusions may also be formed at such blind vias.

[0011] In the context of this application, the term "conductive material defining a through-hole in the lateral direction" may specifically refer to an electrically conductive and / or thermally conductive material that forms at least a portion of the sidewall as the lateral boundary of the through-hole. For example, at least a portion of the conductive material may be the plating material of a coating layer, and / or at least a portion of the conductive material may be the material of the layer structure of the stack, particularly the material of the electrically conductive layer structure of the stack.

[0012] In the context of this application, the term "coating layer" may specifically refer to a structure, particularly a thin film structure, which may be or is actually formed by coating. In particular, the coating layer can be formed by electroless coating (e.g., by sputtering) and / or electroplating (e.g., by electroplating). The coating layer may comprise a single homogeneous layer formed by coating or by a stack of coated sublayers.

[0013] In the context of this application, the term "axial annular protrusion" may specifically refer to a physical structure disposed at the end and / or around a through-hole and extending at least partially along an axial direction corresponding to the axis of the through-hole. Preferably, the axial direction may be parallel to the stack thickness direction. In particular, such an axial annular protrusion may project vertically upward or downward beyond the surrounding stack portion. The axial annular protrusion may also optionally be integrally formed with a radial annular protrusion, or may be arranged separately from such a radial annular protrusion.

[0014] In the context of this application, the term "radial annular protrusion" may specifically refer to a physical structure that extends inward from the sidewall of a through-hole and is at least partially perpendicular or angled to an axial direction corresponding to the axis of the through-hole. The radial annular protrusion may also optionally be integrally formed with an axial annular protrusion, or may be arranged separately from such an axial annular protrusion. Preferably, the direction of the radial annular protrusion may be parallel to the main extension direction of the electronic board and / or the stack.

[0015] In the context of this application, the term "end of a via" may specifically refer to one of two opposite end regions or ends of a via. For example, the end of a via can connect the via to the periphery of a stack or electronic board.

[0016] In the context of this application, the term "main surface" may specifically refer to one of the two largest opposing surfaces of a body or the outermost opposing surface of a body. Main surfaces can be connected by circumferential sidewalls. The thickness of a body (e.g., a stack or layer structure) may be defined by the distance between two opposing main surfaces.

[0017] According to an exemplary embodiment of the present invention, an electronic board (such as a PCB) includes (preferably rolled or laminated) a layered stack having an electrically insulating layer structure sandwiched between electrically conductive layer structures. Through-holes pass through the stack and may have conductive material at least partially covering their sides. One or more plating layers at least partially cover at least a portion of two opposite main surfaces of the stack, preferably covering all of the two opposite main surfaces, and at least a portion of the sidewalls of the stack, preferably covering the entire sidewalls, serving as at least a portion of the lateral boundaries of the through-holes. Furthermore, one or more axial annular protrusions are formed at one or both axial ends of the through-holes. Additionally, one or more radial annular protrusions extend inwardly from the sidewalls of the stack. This configuration (one embodiment of which is as follows) Figure 2 (As shown) can be a fingerprint area with a through hole formed by mechanical drilling, especially using, for example, Figure 1 The sandwich configuration is shown. This electronic board and the corresponding manufacturing method can correspond to the characteristic through-hole shape and electronic board boundary with reduced burrs during mechanical drilling, especially when the stack uses a relatively soft metal layer (such as rolled copper foil). Advantageously, during such mechanical drilling, one or more separation foils can separate the stack from the surrounding environment to obtain the geometry with reduced burrs.

[0018] Detailed Description of Exemplary Implementations Exemplary embodiments of the electronic board and method will be further described below.

[0019] In one embodiment, the axial annular protrusion is at least partially defined by one electrically conductive layer structure and / or the other electrically conductive layer structure and / or at least one plating layer. Additionally or optionally, the radial annular protrusion is at least partially defined by one electrically conductive layer structure and / or the other electrically conductive layer structure and / or by at least one plating layer. Descriptively, the material composition of the stack can be altered by a mechanical drilling process, which may create moderately vertical or axial protrusions at the top and / or bottom. The protrusions can then be covered by at least one plating layer, resulting in the geometry and corresponding material composition. A similar phenomenon may also occur within through-holes, forming one or more radial annular protrusions based on the surrounding stacked material. The axial annular protrusions and / or radial annular protrusions can be patterned on the exposed surface of the electronic board, which can simplify the handling and / or gripping of the electronic board by human and / or machine operators, as the axial annular protrusions and / or radial annular protrusions can be configured as friction-mediated aids.

[0020] In one embodiment, the electronic board has only a single axial annular protrusion. This can be achieved by processing the stack during mechanical drilling to prevent or strongly suppress the formation of the protrusion on one of the two main surfaces. Alternatively, a planarization process, such as grinding, can be performed on only one main surface of the stack after drilling.

[0021] In another embodiment, the electronic board has a corresponding axial annular protrusion at each of the two opposite ends of the through-hole. In particular, two protrusions with different shapes and / or extensions can be formed. When mechanically drilling a stack of thick and / or soft metal plates, a rearrangement of the metal material may occur, resulting in axial annular protrusions on both sides, which may have different appearances.

[0022] In an embodiment, at least one extension of the protrusion is substantially constant in cross-sectional view. Specifically, axial annular protrusions and / or radial annular protrusions may have substantially constant cross-sections along the circumferential portion of the through-hole. Alternatively, axial annular protrusions and / or radial annular protrusions may have different cross-sections along the circumferential portion of the through-hole. Using this method, the manufacture of electronic boards having one or more axial annular protrusions and / or one or more radial annular protrusions with substantially constant cross-sections along the circumferential portion of the through-hole can be simplified in an efficient and simple manner. Preferably, the contact cross-section along the circumferential portion of the through-hole can have high symmetry, such as a mirror plane, which enables the provision of a plating layer with precise plating thickness because the electric field generates symmetrical electric field lines to the associated through-hole.

[0023] In one embodiment, the electronic board includes a plurality of through-holes in the stack, wherein at least one plating layer is provided on the sidewall of the stack defining each through-hole, and each through-hole has a corresponding axial annular protrusion at one end of the corresponding through-hole, and a corresponding radial annular protrusion is provided on the sidewall of the stack defining the corresponding through-hole. A large number of mechanically drilled holes can be formed during panel-level or board-level processing of the electronic board. For example, the electronic board may include at least 10, particularly at least 100, through-holes formed as described herein. Therefore, the manufacturing architecture is appropriately compatible with the mass production of electronic boards, such as PCBs that may involve forming a large number of through-holes.

[0024] In one embodiment, the at least one plating layer, the corresponding axial annular protrusion, and / or the corresponding radial annular protrusion have different thickness distributions depending on the through-hole. For example, different through-holes may be drilled with different parameters, such as different drill bit diameters and / or different rotational speeds.

[0025] In one embodiment, corresponding axial annular protrusions form separate protruding islands around different holes in the through-hole. Such islands can be protruding areas relative to another region, particularly relative to the area surrounding the corresponding island. The axial protrusions may interact with planar main surface areas of the laminate / stack. These axial annular protrusions can form connecting pads, thus allowing connection of components and / or another electronic board to the electronic board. For example, such islands can be formed by axial annular protrusions partially formed from the material of at least one plating layer formed only on a portion of the opposing main surface of the electronic board.

[0026] In one embodiment, the axial annular protrusion extends from the sidewall of the stack. Specifically, the axial annular protrusion may extend partially axially along the through-hole, but may also extend partially laterally into the through-hole. This can potentially provide the advantage of increased mechanical integrity of the axial annular protrusion because the material forming the axial annular protrusion, particularly the plating, alters the elongation direction from axial to radial, or from radial to axial. In other words, these layers can bend at the edges, thereby enhancing mechanical stability (e.g., see reference...). Figure 5 or Figure 9 ).

[0027] In one embodiment, the radial annular protrusion forms a bottleneck portion of the through-hole, such that at least a portion of the through-hole widens at one or both of the one and the other conductive layer structures. Therefore, the radial annular protrusion may form a localized structural contraction or narrowing portion of the through-hole. This can be used for mechanical fasteners, such as pins.

[0028] In one embodiment, the radial annular protrusion is positioned at a height level corresponding to the stacked structure. In terms of manufacturing processes, the mechanical drilling process forming through-holes may rearrange the material of the stack due to mechanical and thermal shocks during drilling. This may result in the axially centered narrow neck being at least partially aligned vertically with the electrical insulation structure. Furthermore, or alternatively, the position of the radial annular protrusion at a height level may be a result of the application of electroplating (especially electroplating) parameters. For example, the electric field at the height level of the electrical insulation layer in the stack may be different compared to the height level of the electrically conductive layer, and thus may affect the deposition of electrically conductive materials such as copper.

[0029] In one embodiment, the through-hole has an inner diameter that increases from the electrical insulating layer structure along the axial direction toward an axial midpoint of one or both of the electrical conductive layer structures, and an inner diameter that decreases further away from the electrical insulating layer structure along the axial direction from the axial midpoint. Descriptively, the resulting geometry can be represented as a drum shape. Figure 3 An example is shown. This shape can give the electronic board greater mechanical stability, thus preventing the electronic board from warping.

[0030] In one embodiment, the inner diameter of the via at the height level of the electrically insulating layer structure differs from the inner diameter of the outer main surface of one or both of the electrically conductive layer structures. The inner diameter path extending along the via can be uniform or non-uniform. This may provide greater flexibility in designing stacked components and / or electronic boards compared to electronic boards with lateral straight-walled vias.

[0031] In one embodiment, the corresponding portion of the sidewall that defines the through-hole and extends between the axial annular protrusion and the radial annular protrusion has a straight shape. Specifically, a cylindrical cross-section of the through-hole can be formed between the central radial annular protrusion and the outer annular protrusion of the axial and / or radial type.

[0032] In one embodiment, the at least one plating layer comprises a plurality of stacked plating layers. Therefore, the at least one plating layer may consist of a plurality of sublayers, each sublayer corresponding to a corresponding plating stage.

[0033] In one embodiment, the innermost plating layer of the stacked plating layers is a seed layer in contact with the electrically insulating layer structure, and also in contact with one or both of the electrically conductive layer structures. This seed layer can be formed by electroless plating (e.g., sputtering or chemical deposition processes), and thus can also cover the non-metallic material of the electrically insulating layer structure. The electrically conductive seed layer can form a base on which one or more additional electrically conductive plating layers can be formed, particularly by electroplating (e.g., electroplating).

[0034] In an embodiment, the seed layer and / or at least one additional plating layer thereon have a substantially constant thickness, particularly with a maximum thickness deviation of less than 10% relative to the seed layer and / or at least one additional plating layer along the entire axial extension of the through-hole. Alternatively or additionally, the seed layer and / or at least one additional plating layer thereon have a substantially constant thickness, particularly with a maximum thickness deviation of less than 10% relative to each of the seed layer and / or at least one additional plating layer along the entire axial extension of the through-hole. Therefore, a single plating layer can have a uniform or substantially uniform thickness in the axial and / or radial directions.

[0035] In one embodiment, the at least one plating layer comprises a plurality of additional plating layers on the seed layer. The additional plating layers can be formed by a plurality of subsequently performed plating stages, particularly an electroplating stage. Preferably, the number of the plurality of plating layers and the number of the plurality of additional plating layers can be the same.

[0036] In one embodiment, the at least one plating layer comprises a plurality of plating layers, wherein the constant or average thickness of each of the plating layers deviates from the constant or average thickness of the plating layers from that of each other by less than 25%. Therefore, the different plating layers may differ only slightly from each other in thickness. This can result in a high degree of structural integrity of the electronic board.

[0037] In one embodiment, the at least one plating layer comprises multiple plating layers, wherein the outermost plating layer comprises a material different from the other materials of one or more inner plating layers. For example, the material may include silver and / or the other materials may include copper. Therefore, the outermost material can be made of a material different from the other plating layers. This can embody the outermost plating layer as a surface treatment material. For example, the outermost plating layer may be made of a corrosion-resistant or oxidation-resistant material, such as silver. Conversely, the remaining one or more inner plating layers may be made of a material specifically suited for another function, for example, to allow low-ohmic current or signal transmission and / or to provide high thermal conductivity (e.g., to facilitate heat dissipation). In this context, the remaining one or more inner plating layers may be made of copper. Using different materials with different plating layers can improve the functionality of the electronic board.

[0038] In one embodiment, the at least one plating layer, particularly comprising a seed layer and at least one additional plating layer thereon, forms at least a portion of the axial annular protrusion and / or radial annular protrusion. However, a portion of the respective protrusion may also be selectively removed, including removing a portion of at least one plating layer, for example by grinding and / or etching. Furthermore, or alternatively, at least one plating layer may have protective properties, such as resistance to the environment, particularly resistance to oxidation and / or moisture. In one example, at least one plating layer may comprise copper and / or nickel and / or silver and / or gold. This can protect the via from decomposition and can ensure that the via has a reliable structure over a long period (e.g., more than 3 years).

[0039] In one embodiment, the axial annular protrusion and the radial annular protrusion are different from each other in the radial and axial directions. Alternatively, the axial annular protrusion and the radial annular protrusion are integrally formed. For example, Figure 2 and Figure 3 One embodiment is shown in which the central radial annular protrusion differs from the other protrusions. The embodiment also shows that an integrally formed axial and radial combined protrusion can be provided at the outer end of the through-hole.

[0040] In one embodiment, the electrical insulating layer structure has an irregular portion on its circumferential portion extending around the through-hole, relative to the corresponding planar main surface of the electrical insulating layer structure. This irregularity may be a fingerprint-like portion formed by mechanical drilling of the through-hole, which may also affect a portion of the electrical insulating layer structure exposed during the mechanical drilling process.

[0041] In one embodiment, the irregular portion of the electrical insulating layer structure includes at least one of a circumferential groove facing the through-hole, a circumferential thickness variation portion, and / or a groove-peak structure. Other types of irregular portions may also be formed.

[0042] In one embodiment, a portion of the at least one plating layer at least partially fills the irregularities of the electrical insulation layer structure. This may be because at least one plating layer can be formed after mechanical drilling, thus allowing for at least partial filling of exposed irregularities in the electrical insulation layer structure.

[0043] In one embodiment, the diameter of the electrically insulating layer structure is smaller than the diameter of the electrically conductive layer structure, including the at least one plating layer, and / or smaller than the diameter of the other electrically conductive layer structure, including the at least one plating layer. For example, Figure 3 This configuration is illustrated. This can have the advantage of ensuring a reliable electrical connection between the two ends of the via, as this design allows for an electrically conductive layer structure covering the sidewalls of the via without completely filling the via and having substantially straight sidewall portions.

[0044] In one embodiment, the diameter of one electrically conductive layer structure is different from the diameter of the other electrically conductive layer structure. Alternatively, the diameters can be the same.

[0045] In one embodiment, a portion of the at least one plating layer is directly disposed on the electrical insulating layer structure, particularly on the side and / or main surface of the electrical insulating layer structure. This plating layer can be formed at least partially by chemical plating, for example by sputtering, which can also allow coverage of the dielectric surface.

[0046] In one embodiment, the electrical insulation layer structure is made of a plastic material, particularly polyimide. Copper layers can be rolled on such plastic layers to form a stack, which can then be mechanically drilled. This can potentially give the electronic board the advantage of flexible behavior. Therefore, after the electronic board is manufactured, it can be bent into a preferred shape.

[0047] In one embodiment, the one electrically conductive layer structure and / or the other electrically conductive layer structure has a thickness of at least 80 μm, particularly at least 100 μm. For such relatively thick electrically conductive layer structures, particularly copper sheets, the stack can be formed by rolling the metal sheet on an electrically insulating layer structure (e.g., plastic foil).

[0048] In one embodiment, the electronic board includes an additional axial annular protrusion disposed at the opposite end of the through hole. Because the mechanical drilling process has different effects on the top and bottom main surfaces of the stack, the two opposite axial annular protrusions may have different characteristics, particularly possibly protruding within different spatial ranges.

[0049] In one embodiment, the electronic board includes at least one additional radial annular protrusion disposed at one end or both opposite ends of the through-hole. Specifically (see, for example) Figure 2 A radial annular protrusion can be formed in the central part of the through hole, and two additional radial annular protrusions can be formed at the two opposite ends or ends of the through hole.

[0050] In one embodiment, the axial annular protrusion protrudes vertically by less than 30 μm, particularly less than 20 μm, and preferably less than 7 μm. In particular, when the application involves a manufacturing process involving mechanical drilling using the separating foil described herein, a significantly lower axial annular protrusion can be obtained compared to conventional burrs. For example, with reference to the drilling process, an axial annular protrusion with a height of less than 30 μm can be obtained on the back side of the stack. For example, with reference to the drilling process, an axial annular protrusion with a height of less than 20 μm can be obtained on the front side of the stack. When further planarization processes are performed, such as polishing processes like chemical mechanical polishing (CMP), an axial annular protrusion with a height of less than 7 μm can be obtained, even when meeting very stringent specifications.

[0051] In one embodiment, the at least one plating layer comprises a plurality of plating layers, wherein, at the circumferential portion of the through-hole, at least one of the plurality of plating layers does not extend or extends discontinuously on at least one main surface of the stack. When selectively grinding the axial annular protrusions on one or both of the two opposite main surfaces of the electronic board, only the outermost plating layer of one or more plating layers may be removed, which may result in a discontinuous plating configuration at the top and / or bottom of the electronic board (see reference). Figure 14 This allows for the exposure of multiple plating layers at preferred locations on the exposed main surface of the electronic board, which can be selectively used for a particular purpose, such as a soldering or sintering process.

[0052] In one embodiment, an edge of one of the plurality of electrically conductive layer structures covered by the at least one plating layer is sharpened, and / or wherein the edge of each corresponding electrically conductive layer structure covered by the at least one plating layer is sharpened. Similarly, this could be the result of a planarization polishing process, as described above, such as... Figure 14 As shown.

[0053] In one embodiment, the method includes forming at least one coating layer, preferably multiple coating layers, by electroplating and / or electroless plating.

[0054] In one embodiment, the method includes forming a through hole in the stacked component by mechanical drilling. Due to the mechanical drilling process, the mechanical drill bit involved may push material near the through hole in a direction parallel to the drill bit's movement, potentially creating axial annular protrusions and / or radial annular protrusions.

[0055] In one embodiment, the method includes forming a through-hole in the stack while positioning the stack between a bottom protective structure and a top protective structure. The bottom and top protective structures can facilitate a configuration in which the intermediate stack does not experience excessive burr formation. Alternatively, the bottom and / or top protective structures can prevent lateral movement of the stack during through-hole formation, particularly during mechanical drilling.

[0056] In one embodiment, the method includes using a plate as a bottom protective structure and / or metal foil, particularly aluminum foil, as a top protective structure. This bottom protective structure provides strong mechanical support. Due to the high thermal conductivity of metal, this top protective structure prevents overheating.

[0057] In one embodiment, the method includes, during the formation of the through-hole, providing a release foil between the stack and the bottom protective structure and / or between the stack and the top protective structure. This release foil (e.g., a polytetrafluoroethylene or waxy surface) may have poor adhesion, so that after the through-hole is drilled, the stack can be easily separated from the release foil without creating a poor bond between the stack and other materials.

[0058] In one embodiment, the method includes forming the through-hole in the stacked member, while simultaneously forming another through-hole in another stacked member. Advantageously, multiple stacked members can be stacked for common drilling of the through-holes. This can increase production capacity.

[0059] In one embodiment, the method includes placing a release foil between the stack and the other stack during the formation of the through-hole. This release foil (e.g., a PTFE or waxy surface) may have poor adhesion, so that after the through-hole is drilled, the release foil can be easily separated from the other stack without creating a poor connection with another stack. Three or more stacks can also be stacked, and the through-hole can be formed by simultaneously mechanically drilling all of these stacks.

[0060] In one embodiment, the method includes grinding one or two opposing main surfaces of the electronic board or its preform, particularly simultaneously, to reduce the height of the axial annular protrusion. For example, this grinding can be performed by chemical mechanical polishing (CMP). Alternatively, the grinding stage can be omitted due to the described manufacturing process, as the manufacturing process automatically generates only small burrs.

[0061] In one embodiment, the electronic board includes a stack of at least one electrically insulating layer structure and at least one electrically conductive layer structure. For example, the electronic board can be a laminate of one or more electrically insulating layer structures and one or more electrically conductive layer structures, particularly a laminate formed by applying mechanical pressure and / or heat. The aforementioned stack can provide a plate-shaped electronic board, offering a large mounting surface for components and being very thin and compact.

[0062] In one embodiment, the electronic board is shaped into a plate. This facilitates compact designs, where the electronic board provides a large base for mounting components. In particular, bare chips of electronic components, for example, can be surface-mounted on a thin plate (e.g., a printed circuit board).

[0063] In one embodiment, the electronic board is configured as one of the groups consisting of a printed circuit board, a substrate (particularly an IC substrate), and an interposer.

[0064] In the context of this application, the term "printed circuit board" (PCB) can specifically refer to a sheet-like electronic board formed by laminating several electrically conductive layer structures with several electrically insulating layer structures, for example by applying pressure and / or by providing heat. As preferred materials for PCB technology, the electrically conductive layer structures are made of copper, while the electrically insulating layer structures may include resin and / or glass fiber, i.e., so-called prepreg or FR4 material. Various electrically conductive layer structures can be interconnected in the desired manner by forming holes through the laminate (e.g., by laser drilling or mechanical drilling) and filling them partially or entirely with an electrically conductive material (particularly copper). These holes either connect the entire stack (through-hole connections extending through several layers or the entire stack) or connect at least two electrically conductive layers, referred to as vias. Similarly, optical interconnects can be formed through the various layers of the stack to receive electro-optical circuit boards (EOCBs). Printed circuit boards are typically constructed to house one or more components on one main surface or two opposite surfaces of a sheet-like printed circuit board. They can be soldered to the respective main surfaces. The dielectric components of a PCB can be composed of resin and reinforcing fibers (such as glass fiber).

[0065] In the context of this application, the term "substrate" can specifically refer to a small electronic board, particularly an IC substrate. Compared to a PCB, an IC substrate can be a relatively small electronic board on which one or more components can be mounted, and can act as a connection medium between one or more chips and another PCB. For example, an IC substrate can have substantially the same size as the components (particularly electronic components) to be mounted thereon (e.g., in the case of a chip-scale package (CSP)). More specifically, an IC substrate can be understood as a carrier of electrical connections or electrical networks, and an electronic board equivalent to a printed circuit board (PCB), but with a much higher density of connections arranged laterally and / or vertically. For example, lateral connections are conductive paths, while vertical connections can be, for example, drilled holes. These lateral and / or vertical connections can be specifically arranged within the IC substrate and can be used to provide electrical, thermal, and / or mechanical connections for enclosed components or non-inserted components (e.g., bare dies) with printed circuit boards or intermediate printed circuit boards, particularly for IC chips. In the context of this application, "substrate" particularly facilitates electrical connections and / or heat dissipation and / or provides mechanical strength. Therefore, in the context of this application, the term "substrate" is specifically used as a synonym for "IC substrate." It must be noted that the term "substrate" should not be confused with the term "substrate" in particular, as it is commonly used in the wafer environment, where "substrate" typically refers to the substrate material used in wafer fabrication as a substrate for constructing devices or circuits and forming the foundational layer supporting the electronic or photonic structures integrated into the wafer. This is not the meaning of "substrate" in the context of this application.

[0066] The substrate or interlayer may contain or consist of at least one layer of glass, silicon (Si), and / or photo-imageable or dry-etchable organic material, such as epoxy-based stacked materials (e.g., epoxy-based stacked films) or polymer compounds (which may or may not include photosensitive molecules and / or thermosensitive molecules), such as polyimide or polybenzoxazole.

[0067] In one embodiment, the at least one electrically insulating layer structure comprises at least one of the following: resins or polymers such as epoxy resins, cyanate ester resins, benzocyclobutene resins, melamine derivatives, polybenzo[a]methyl methacrylate (PBO), bismaleimide-triazine resins, polyphenylene derivatives (e.g., based on polyphenylene ether, PPE), polyimide (PI), polyamide (PA), liquid crystal polymers (LCP), polytetrafluoroethylene (PTFE), bisbenzocyclobutene (BCB), and / or combinations thereof. Reinforcing structures, such as mesh structures, fibers, spheres, or other types of filler particles, may also be used, for example, made of glass (multilayer glass) to form a composite material. The semi-cured resin combined with a reinforcing agent (e.g., fibers impregnated with the aforementioned resins) is called a prepreg. These prepregs are typically named for their properties, such as FR4 or FR5, which describe their flame-retardant properties. While prepregs, particularly FR4, are generally preferred for rigid PCBs, other materials may also be used, particularly epoxy-based stacked materials (e.g., stacked films) or photo-imageable dielectric materials. 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, or ultra-low DK materials can be used as electrical insulation structures in electronic boards.

[0068] In one embodiment, the at least one electrically conductive layer structure comprises at least one material selected from the group consisting of copper, aluminum, nickel, silver, gold, palladium, tungsten, titanium, and magnesium. While copper is generally preferred, other materials or coated versions thereof may also be used, particularly those coated with superconducting materials or conductive polymers, such as graphene or poly(3,4-ethylenedioxythiophene) (PEDOT).

[0069] At least one component that can be surface-mounted on and / or embedded in an electronic board can be selected from at least one of the following: non-conductive inlays, conductive inlays (e.g., metal inlays, preferably including copper or aluminum), heat transfer units (e.g., heat pipes), light guiding elements (e.g., optical waveguides or optical conductor connections), electronic components, or combinations thereof. For example, the inlay can be a metal block with or without an insulating material coating (IMS inlay), which can be surface-mounted to facilitate heat dissipation. Suitable materials are defined by their thermal conductivity, which should be at least 2 W / mK. Such materials are typically based on, but not limited to, metals, metal oxides, and / or ceramics, such as copper, alumina (Al₂O₃), or aluminum nitride (AlN). Other geometries that increase surface area are also frequently used to increase heat exchange capacity. Furthermore, the components can be active electronic components (having at least one pn junction), passive electronic components such as resistors, inductors or capacitors, electronic chips, storage devices (such as DRAM or other data memories), filters, integrated circuits (such as field-programmable gate arrays (FPGAs), programmable array logic (PALs), general-purpose array logic (GALs), and complex programmable logic devices (CPLDs)), signal processing components, and power management components (such as field-effect transistors (FETs), metal-oxide-semiconductor field-effect transistors (MOSFETs), complementary metal-oxide-semiconductor (CMOS) transistors, and junction field-effect transistors (JF-MOSFETs). Electronic components include (ET) or insulated-gate field-effect transistors (IGFETs), both based on silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), gallium oxide (Ga2O3), indium gallium arsenide (InGaAs) and / or any other suitable inorganic compound, optoelectronic interface elements, light-emitting diodes, optocouplers, voltage converters (e.g., DC / DC converters or AC / DC converters), encryption elements, transmitters and / or receivers, electromechanical sensors, sensors, actuators, microelectromechanical systems (MEMS), microprocessors, capacitors, resistors, inductors, batteries, switches, cameras, antennas, logic chips, and energy harvesting units. However, other components can be surface-mounted on the electronic board. For example, magnetic components can be used as components. Such magnetic components can be permanent magnets (e.g., ferromagnetic, antiferromagnetic, multiferroic, or ferrimagnetic elements, such as ferrite cores) or paramagnetic elements. However, the component can also be an IC substrate, interposer, or another electronic board, such as in a board-in-board configuration. The component can be surface-mounted on the electronic board. In addition, other components may be used, especially those that generate and emit electromagnetic radiation and / or are sensitive to electromagnetic radiation propagating from the environment.

[0070] In one embodiment, the electronic board is a laminated electronic board. In such an embodiment, the electronic board is a multi-layered composite structure, which is stacked together by applying pressure and / or heat.

[0071] After processing the inner layer structure of the electronic board, one or more additional electrically insulating and / or electrically conductive layer structures can be used to symmetrically or asymmetrically cover (especially by lamination) one main surface or two opposite main surfaces of the processed layer structure. In other words, stacking can continue until the desired number of layers is obtained.

[0072] After the stacked components of the electrical insulation layer structure and the electrical conductivity layer structure are formed, the obtained layer structure or electronic board can be surface treated.

[0073] In particular, regarding surface treatment, an electrically insulating solder resist can be applied to one or two opposite main surfaces of a laminate or electronic board. For example, this solder resist can be formed over the entire main surface, and the resist layer can then be patterned to expose one or more electrically conductive surface portions used for electrical coupling between the electronic board and electronic peripherals. The surface portions of the electronic board remain covered with solder resist, effectively preventing oxidation or corrosion, especially for copper-containing surfaces.

[0074] In terms of surface treatment, the exposed electrically conductive surface portions of an electronic board can also be selectively surface-treated. This surface-treated portion can be an electrically conductive covering material on the exposed electrically conductive layer structure (e.g., pads, conductive tracks, etc., particularly containing or composed of copper) of the electronic board surface. If this exposed electrically conductive layer structure is not protected, the exposed electrically conductive electronic board material (especially copper) may oxidize, thereby reducing the reliability of the electronic board. The surface-treated portion can then be formed, for example, as an interface between surface-mount components and the electronic board. The surface-treated portion functions to protect the exposed electrically conductive layer structure (especially copper circuitry) and enables connection processes with one or more components, such as by soldering. Examples of materials suitable for surface treatment include organic solderable preservatives (OSP), electroless nickel immersion gold (ENIG), electroless nickel immersion palladium immersion gold (ENIPIG), gold (especially hard gold), electroless tin, nickel-gold, nickel-palladium, etc. Attached Figure Description

[0075] The aspects defined above and others of the present invention will become apparent from the examples of embodiments described below and will be explained with reference to these examples of embodiments.

[0076] Figure 1 A cross-sectional view of a structure obtained during the execution of a method for manufacturing an electronic board according to an exemplary embodiment of the present invention is shown.

[0077] Figure 2 A cross-sectional view of an electronic board according to an exemplary embodiment of the present invention is shown.

[0078] Figure 3A cross-sectional image of an electronic board according to an exemplary embodiment of the present invention is shown.

[0079] Figure 4 A cross-sectional image of an electronic board according to an exemplary embodiment of the present invention is shown.

[0080] Figures 5 to 12 It shows that according to Figure 4 Details of the image on the electronic board.

[0081] Figure 13 A cross-sectional image of an electronic board according to an exemplary embodiment of the present invention is shown.

[0082] Figure 14 A cross-sectional image of an electronic board according to an exemplary embodiment of the present invention is shown. Detailed Implementation

[0083] The illustrations in the accompanying drawings are schematic. In different drawings, similar or identical elements are provided with the same reference numerals.

[0084] Before describing the exemplary embodiments in further detail with reference to the accompanying drawings, some basic considerations on which the exemplary embodiments of the present invention are based will be summarized.

[0085] For certain applications within the manufacturing framework of electronic boards (such as PCBs), rolled copper foil (so-called RA copper, or "rolled annealed copper") is used and subjected to mechanical drilling during manufacturing to form through-holes. Due to the specific characteristics of this rolled copper foil, packages can traditionally be manufactured one stack at a time. When attempting to perform the manufacturing method using a stack configuration of two or more stacks, the sheets tend to stick together and / or produce noticeable surface indentations and burrs. In undesirable cases, the stacks may exhibit behaviors of adhesion, bonding, or soldering to the overlay sheet. Very satisfactory results can be obtained when there are separating or release foils between them. Alternatively, plated copper foil can be implemented.

[0086] According to an exemplary embodiment of the invention, a preferred PCB-type electronic board is provided with a stack (preferably formed by lamination, i.e., applying heat and / or pressure to interconnect different layer structures, or formed by calendering), the stack including at least one electrically insulating layer structure located between two or more electrically conductive layer structures. During the manufacturing process, one or more (e.g., at least 10 or at least 1000) through-holes are formed in the stack, preferably by mechanical drilling using a rotary drill bit. The sidewalls of the stack may be partially or completely coated with a conductive material, preferably an electrically conductive material. At least one plating layer partially or completely covers the main surface of the stack and the sidewalls of the through-holes. Furthermore, at least one axial annular protrusion extends axially at at least one end defining the through-hole. In addition, at least one radial annular protrusion extends inward from the sidewall of the through-hole, preferably extending inside the through-hole, and optionally extending axially between two opposite axial annular protrusions located at the ends of the through-hole. The described geometry (see examples shown) Figure 2 It can be produced by a through hole formed by mechanical drilling, for example by... Figure 1 Through-holes are created by mechanically drilling based on the layout structure. Compared with the conventional method of obtaining through mechanical drilling, electronic boards manufactured in this way can advantageously exhibit fewer burrs. Therefore, electronic boards can be manufactured on an industrial scale with increased production volume.

[0087] In particular, mechanical drilling of multiple layered stacks with separating foils between them has proven to be an efficient manufacturing method that results in high-quality electronic boards.

[0088] Advantages gained through this implementation include reduced burrs from mechanical drilling due to the electrically conductive layer structure (particularly with RA copper foil thicker than 100 μm, the burr height does not exceed 30 μm, and more specifically, the burr height is in the range of 1 μm to 30 μm). Alternatively, the burr height can be in the range of 1% to 30% of the thickness of the electrically conductive layer structure with through-holes. This manufacturing method can also improve efficiency by increasing the stacking height, thereby reducing manufacturing time and thus reducing manufacturing workload. Furthermore, exemplary embodiments can allow for increased surface quality of the resulting electronic board and can allow for reduced surface indentation. Advantageously, residues of the release foil or release film do not remain on the manufactured electronic board. Advantageously, this manufacturing architecture can be particularly advantageously applied to thin laminates with rolled copper foil (e.g., RA copper). During mechanical drilling, multiple layered stacks are stacked together with separator foils between them, making it possible to mechanically drill the multiple layered stacks simultaneously. Manufacturing efficiency can be significantly increased by using double stack heights or even stack heights involving three or more stacks, which are simultaneously mechanically drilled to form through holes.

[0089] In some embodiments, different burr sizes can be obtained on opposite sides of the PCB-type electronic board. For optional planarized electronic boards, chemical mechanical polishing (CMP) can be performed to obtain a smooth area in order to further reduce the burr height. However, in other embodiments, since the burr height obtained by the exemplary embodiments is already significantly reduced, a separate planarization stage, such as a planarization stage by grinding, can be omitted, and more specifically, a planarization stage by chemical mechanical polishing can be used.

[0090] According to an exemplary embodiment, an electronic board is provided, comprising a stacked member including at least one electrically insulating layer structure and a plurality of electrically conductive layer structures. One of the plurality of electrically conductive layer structures may be disposed on one surface of the at least one electrically insulating layer structure, and another of the plurality of electrically conductive layer structures may be disposed on the opposite surface of the at least one electrically insulating layer structure. The electronic board may further include: a through-hole defined laterally by a conductive material, and at least one plating layer disposed on the main surface of the stacked member and on the sidewall of the through-hole. An axial annular protrusion (which may be defined by the electrically conductive layer structure and / or the plating layer) may be provided at at least one end of the through-hole. Furthermore, a radial annular protrusion may be provided on the sidewall of the through-hole.

[0091] Preferably, the axial annular protrusion can be provided on only one surface (or on two surfaces). In an embodiment, two protrusions can be formed, one on each of two opposite main surfaces of the main surface. In particular, two protrusions with different shapes and / or extensions can be formed. In one embodiment, the protrusion has a constant cross-section along its circumferential portion. Alternatively, the axial annular protrusion can have a variable cross-section along its circumferential portion. For example, multiple through holes can be provided. In particular, at least one conductive layer with different stack thickness distributions can be formed between two through holes. Advantageously, one or more protruding islands can be provided around the through holes on one main surface of the layer. For example, the protrusions can extend axially from at least one main surface and / or radially from the sidewall of the through hole.

[0092] Referring now to the radial annular protrusion, an enlarged portion of the through-hole can be formed at one or both conductive layer structures that are in contact with at least one insulating layer structure. Furthermore, a drum-shaped form can be defined (particularly having a diameter that increases from the electrical insulating layer structure toward the middle of one or more of the electrical conductive layer structures, and decreases from the middle toward the surface away from the electrical insulating layer structure). In one embodiment, the diameter of the through-hole at the insulating structure can be different from (particularly smaller than) the diameter at the outer surface of the stack. For example, the protrusion has a substantially uniform cross-section along its circumferential portion. Alternatively, the radial annular protrusion has a varying cross-section along its circumferential portion. For example, the sidewalls of the through-hole extending between the axial and radial protrusions have a cylindrical (or straight) shape. In one embodiment, a seed layer is provided that contacts at least one electrical insulating layer structure. For example, a seed layer is provided that contacts at least one electrical insulating layer structure and one of the two conductive layer structures. In one embodiment, one or both of the seed layer and the plating layer have the protrusion. For example, the seed layer and the plating layer have substantially the same thickness along the extension of the through-hole. In one embodiment, one or each of the plating layers has the same thickness along the circumferential portion of the through-hole (i.e., at the same vertical horizontal level), particularly with a deviation of less than 10%. For example, the plating layers at one or more sidewalls of the through-hole have the same thickness, particularly with a deviation of less than 25%. In one embodiment, the sum of the thicknesses of the plating layers and / or the seed layer may be less than the thickness of at least one electrically conductive layer structure (relative to the stacking thickness direction). In one embodiment, several plating layers stacked from the seed layer may be provided. For example, the protrusions are not connected to each other radially or along the front side. For example, the outermost layer is made of a different material than the other (conductive or plating) layers, particularly silver (e.g., copper).

[0093] Regarding the (particularly central) insulating layer structure, irregularities may exist at one or more planar main surfaces corresponding to the circumferential portion around the through-hole. For example, (preferably circumferential) grooves may be formed. In particular, thickness variations may exist towards the circumferential portion. For example, grooves and peaks may be formed at the holes in the insulating structure. In one embodiment, the diameter in the insulating layer structure is smaller than the diameter of one and another of the conductive layer structures. For example, the diameter of one conductive layer structure in the conductive layer structure is different from the diameter of another conductive layer structure in the conductive layer structure. In one embodiment, the plating layer extends at least partially on the main surface of the insulating layer. At least partial filler may be present, preferably filler on the sides of the (preferably circumferential) groove. On the sides of the (preferably circumferential) groove, the conductive layer may have a diameter larger than the diameter of the opposite conductive layer.

[0094] Referring now to an optional grinding process for further reducing the burr height of the electronic board, this grinding can be performed on one or both sides of the electronic board. Specifically, at least one layer at the circumferential portion of the through-hole does not extend or extends discontinuously at one of the main surfaces of the stack. For example, the outer edge of the through-hole is rounded along the thickness direction. For example, an edge of one of the conductive layers is sharpened. In an embodiment, the edge of the corresponding conductive layer is sharpened.

[0095] For example, grinding can be performed after plating because electronic boards, or panels comprising multiple electronic boards, may be more stable. Grinding can be performed to deburr. For example, grinding can include treating the electronic board with a ceramic brush, allowing for a purely mechanical grinding process. Grinding may also be accompanied by chemical reagents, such as pastes. Grinding can be performed simultaneously on opposite sides of the electronic board.

[0096] The manufacturing process can be performed on the already separated electronic boards or on individual electronic boards. Alternatively, the manufacturing process can be performed on a preform of the electronic board, such as a panel, which comprises multiple electronic boards that are still integrally connected, i.e., performed at the panel level. For example, at the end of the manufacturing process, such a panel can be separated into multiple individual electronic components by milling.

[0097] Drilling holes in an electronic board or panel can include creating multiple through-holes. For example, more than 1,000 through-holes can be created on each panel. The through-holes can be arranged in rows and columns, i.e., in a matrix pattern.

[0098] According to exemplary embodiments, it is possible to perform low-burr or even burr-free mechanical drilling of copper sheets. More specifically, during the mechanical drilling of copper (particularly rolled copper sheets), burrs that may be generated on the outer surface portion of the stack can be significantly reduced. Preferably, when the encapsulation of the stacked panels is simultaneously mechanically drilled to form through-holes, one or more separation foils can be provided between adjacent panels.

[0099] Without a release foil between stacked panels or stacked electronic boards, rolled copper material may interact with the layers above and / or below. Because rolled copper is quite flexible, mechanical drilling can create permanent bonds between the rolled copper material and other materials. However, when a release foil is used according to an exemplary embodiment of the invention, interconnections with other layers or materials can be reliably prevented, and burrs on the copper layers can be further reduced. Due to the mechanical drilling process, burrs formed on the top side are likely to be smaller than those formed on the bottom side. Furthermore, if desired or required, a chemical mechanical polishing (CMP) process can be applied to further reduce burrs to meet stringent quality requirements.

[0100] Therefore, exemplary embodiments of the present invention implementing one or more separate foils can achieve mechanical drilling of rolled copper without interacting with spare boards, aluminum inlet foils, or with other stacked panel or electronic board preforms (see reference). Figure 1 Therefore, production volume can be increased, and burrs around mechanically drilled holes can be kept within specifications. Relatively soft rolled copper (also known as RA copper) can make the mechanical drilling process challenging, where the aforementioned process can allow for the production of electronic boards with advantageous properties while resulting in high production volumes. This even allows for the processing of thick copper layers, such as those with a thickness greater than 80 μm, and particularly those with a thickness greater than 100 μm, such as those with a thickness of 105 μm. Mechanical drilling can be performed simultaneously on stacks of two, three, or more electronic boards or panels with excellent results.

[0101] Figure 1 An exemplary embodiment of the present invention is shown in the process of manufacturing an electronic board 100 (e.g. Figure 2 The cross-sectional view of the structure obtained during the method shown in the electronic board.

[0102] Figure 1 A working stack 152 is shown, which can be constructed to form through holes by mechanical drilling using one or more rotatable drill bits 154. Although Figure 1Only a single drill bit 154 is shown to form a single through-hole that extends simultaneously through multiple stacks 102, 102', but it is foreseeable that multiple drill bits, and / or drill bits that can move relative to the surface of the working stack 152, can simultaneously and / or subsequently form multiple through-holes. For example, for processing panels that each comprise multiple electronic boards 100 to be processed together, at least 100 through-holes can be formed per panel, and particularly at least 1000 through-holes per panel. For example, each electronic board 100 may include at least 10 through-holes, and particularly at least 100 through-holes.

[0103] See again Figure 1 The illustrated working stack 152 may include a bottom protective structure 144 on the bottom side and a top protective structure 146 on the top side. Multiple stacks 102, 102' may be stacked between the bottom protective structure 144 and the top protective structure 146. Each stack 102, 102' may correspond to a panel to be processed, or may correspond to a preform of an electronic board 100 to be processed. Advantageously, one or more release foils 148 may be spatially disposed between adjacent components of the working stack 152 to separate adjacent components from each other during mechanical drilling. In the illustrated configuration, a release foil 148 may be disposed between the bottom protective structure 144 and the lowermost stack 102. Additional release foils 148 may be disposed between adjacent stacks 102, 102'. Yet another release foil 148 may be disposed between the uppermost stack 102' and the top protective structure 146.

[0104] For example, the bottom protective structure 144 can be formed as a spare board, such as a printed circuit board or a printed circuit board panel or a virtual structure. The bottom protective structure 144 can be configured to provide mechanical support to the components of the working stack 152 during mechanical drilling. Each of the stacks 102, 102' can be formed as an electronic board or a preform of an electronic board, or as a panel comprising a plurality of integrally connected electronic board preforms. Through-holes are formed in the stacks 102, 102' by mechanical drilling using one or more drill bits 154. Although Figure 1 Two vertically stacked elements 102, 102' are shown, but three or more such elements can also be stacked one on top of the other. The top protective structure 146 can be formed as a metal inlet foil, for example, made of aluminum. The metal inlet foil has high thermal conductivity, thereby preventing the drill bit 154 from overheating during mechanical drilling, while reducing burr formation during drilling.

[0105] Particularly advantageous are spacers in the form of release foil 148. For example, this release foil 148 can be made of polyimide, polytetrafluoroethylene, or other polymers. The release foil 148 is preferably made of a material with poor adhesive properties, allowing the individual stacks 102, 102' to separate from each other and from the protective structures 144, 146 after drilling is performed by mechanical drilling. In addition to preventing undesirable integral connections between adjacent drilled structures (e.g., by accidental welding) during the mechanical drilling process, the release foil 148 also has a positive effect on reducing burr formation, particularly on reducing the burr height on the opposite main surfaces of the drilled stacks 102, 102'. Furthermore, the use of this separation or release foil 148 can produce very specific shapes for the electronic board 100, particularly around the formed drill holes 120 (see...). Figure 2 or Figure 3 ).

[0106] like Figure 1 As shown in detail 156, the stack 102 (and its corresponding stack 102', not shown) includes an electrically insulating layer structure 104 disposed between two electrically conductive layer structures 106, 108. For example, the electrically insulating layer structure 104 may include a resin (e.g., epoxy resin) and optional reinforcing particles (e.g., glass beads of glass fiber). However, the electrically insulating layer structure 104 may also be made of a plastic material, particularly polyimide. Alternatively, the electrically insulating layer structure 104 of the stack may not contain reinforcing particles and / or may be made of a flexible material such as polyimide or polyisoprene. The electrically conductive layer structures 106, 108 may be copper sheets, particularly copper sheets made of rolled copper. In the already stacked... Figure 1 After the working stack 152, when the stacks 102 and 102' are arranged to be stacked between the bottom protective structure 144 and the top protective structure 146 and spaced apart from the adjacent structures by the release foil 148, the manufacturing method continues to mechanically drill holes using one or more rotary drill bits 154 to simultaneously form through holes in the stacks 102 and 102' (see...). Figure 2 , Figure 3 (Figure reference 120).

[0107] During the drilling process, a rounded axial annular protrusion may be formed at the opposite ends or tips of the through holes 120 in each stack 102, 102' (see...). Figure 4 or Figure 5 Alternatively, edge protrusions (particularly axial annular protrusions) may be created. Furthermore, during mechanical drilling and / or during plating, one or more radial annular protrusions may be formed at the sidewall defining the through-hole 120 (see reference). Figure 2 or Figure 3 (Referring to reference numerals 130, 132, 134 in the accompanying drawings). For example, in... Figure 2 or Figure 3 In this configuration, one or more radially annular protrusions 130, 132, 134 may be at least partially formed by a plating layer. However, for example in... Figure 7 As can be seen, a radial annular protrusion can also be created in one or more electrically conductive layer structures 106 (108) through the drilling process, as well as in the plating layer on top of the protrusion, which increases the radius of the protrusion and / or makes the protrusion more prominent.

[0108] After the drilling process is completed, the obtained processed working stack 152 can be separated by separating the components of the obtained processed working stack 152 from each other. In particular, the processed stacks 102, 102' can be easily separated from the release foil 148 without the risk of accidental interconnection between adjacent components due to the mechanical drilling process. Furthermore, the separation foil or release foil 148 can be removed from the stacks 102, 102' without leaving any protective foil or release foil 148 residue on the stacks 102, 102'.

[0109] Subsequently, the manufacturing process of the electronic board 100 can continue on the two opposite main surfaces of the corresponding stacked parts 102, 102' (see reference). Figure 2 and Figure 3 One or more plating layers are formed on the reference numerals 114, 116 and on the sidewalls 118 of the corresponding stacked parts 102, 102' (see Figure 114, 116). Figure 2 and Figure 3 (Ref. 122 in the figure). The formation of the coating 122 can be accomplished by electroless plating (e.g., sputtering and / or wet chemical processing) followed by electroplating (e.g., electroplating).

[0110] Optionally, the method may then continue to grind one or both opposite main surfaces of the electronic board 100 or the stack 102, 102' to further reduce the height of the axial annular protrusions 126, 128. This grinding can be performed, for example, by chemical mechanical polishing (CMP), and can reduce the height of the axial annular protrusions 126, 128, particularly by removing material from the plating layer 122 in the corresponding areas. In other embodiments, due to the manufacturing method, the height of the burrs has been strongly suppressed, and therefore chemical mechanical polishing can be omitted. For example, the top-side burrs of the drilled stack 102, 102' may have a height of less than 20 μm, and the bottom-side burrs of the drilled stack 102, 102' may have a height of less than 30 μm.

[0111] refer to Figure 2 and Figure 3 This will explain the geometry obtained by the manufacturing method described. Figure 2 It is a schematic cross-sectional view, and Figure 3 The image shown is an experimental image of the manufactured electronic board 100.

[0112] Figure 2 A cross-sectional view of an electronic board 100 according to an exemplary embodiment of the present invention is shown. The electronic board 100 can be formed as a printed circuit board (PCB) or the like. Although Figure 2 The diagram shows only one through hole 120, but the electronic board 100 may include multiple through holes 120, such as at least 10 or at least 100 through holes 120.

[0113] according to Figure 2 The electronic board 100 includes a laminated or rolled layered stack 102, which includes a central electrically insulating layer structure 104 sandwiched between two outer peripheral electrically conductive layer structures 106, 108. One electrically conductive layer structure 106 is formed on the bottom main surface 110 of the electrically insulating layer structure 104. The other electrically conductive layer structure 108 is disposed on the opposite upper main surface 112 of the electrically insulating layer structure 104. In the illustrated embodiment, the electrically insulating layer structure 104 can be, for example, a sheet of resin, prepreg, or FR4. However, the electrically insulating layer structure 104 can also be made of a plastic material, particularly polyimide. Either of the electrically conductive layer structures 106, 108 can be rolled copper sheet, which can be relatively flexible. The electrically conductive layer structures 106, 108 can be relatively thick. For example, one of the electrically conductive layer structures 106 can have a thickness L of at least 80 μm. Accordingly, the other electrically conductive layer structure 108 may have a thickness L of at least 80 μm, particularly at least 100 μm. Preferably, the two corresponding electrically conductive layer structures 106, 108 may be similar, or may have a deviation of less than 10%, particularly less than 5%.

[0114] The through-hole 120 may be, for example, a vertical or generally vertical through-hole, formed in the stack 102 and extending through the entire stack 102, to be open at the upper end or end of the stack 102 and at the lower end or end of the stack 102. The through-hole 120 can be formed by using, for example... Figure 1 The hole is formed by mechanical drilling using the rotary drill bit 154 shown.

[0115] The through-hole 120 is laterally defined by the electrically and thermally conductive material of the coating layer 122, such as... Figure 2As shown. In the example, the electrically and thermally conductive materials can have a conductivity higher than 10. 5 Electrical conductivity of S / m (or lower). In another example, the electrically and thermally conductive material may have a thermal conductivity greater than 100 W / mK. The coating layer 122 is disposed on the two opposite main surfaces 114, 116 of the stack 102 and on the sidewall 118 of the stack 102.

[0116] like Figure 2 As shown in detail 160, the plating layer 122 is formed here as a plurality of stacked plating layers of different types 122', 122''. More specifically, the innermost layer structure of the stacked layer structures 122', 122'' formed on the exposed portions of the layer structures 104, 106, 108 is a seed layer 122' that is in direct physical contact with the electrically insulating layer structure 104 and the two electrically conductive layer structures 106, 108.

[0117] The seed layer 122' and the additional plating layer 122'' thereon can have a substantially constant thickness, with a maximum thickness deviation of less than 10% relative to the corresponding one of the seed layer 122' and the additional plating layer 122'' along the entire axial extension of the through-hole. Furthermore, the seed layer 122' and the additional plating layer 122'' thereon can have a substantially constant thickness, with a maximum thickness deviation of less than 10% relative to the corresponding one of the seed layer 122' and the additional plating layer 122' along the entire lateral circumferential portion of the through-hole 120. The deviation of the constant thickness or average thickness of each of the plating layers 122', 122'' from the constant thickness or average thickness of the others of the plating layers 122', 122'' can be less than 25%. Therefore, the plating layers 122', 122'' can have homogeneous properties.

[0118] The material of the outermost plating layer exposed in the through-hole 120 of the plating layers 122', 122'' may differ from the material of one or more of the inner plating layers of the plating layers 122', 122''. For example, the outermost plating layer of the plating layers 122', 122'' may include silver, while all other components or internal components of the plating layer 122 may include copper. Thus, the outermost plating layer of the plating layers 122', 122'' may be a surface-treated portion that can prevent, for example, corrosion or oxidation, while the internal components of the plating layer 122 may be optimized to provide high conductivity. However, other functional adaptations of the components of the plating layer 122 are feasible. A portion of the plating layer 122 may be directly disposed on the electrically insulating layer structure 104. This can be achieved, in particular, by electroless plating.

[0119] In addition, according to Figure 2The electronic board 100 includes opposing axial annular protrusions 126 and 128, each disposed at a corresponding upper and lower end of the through hole 120. The axial annular protrusion 128 protrudes vertically beyond a corresponding distance D of the planar upper surface portion 166 of the electronic board 100, or protrudes vertically beyond a corresponding distance d of the planar lower surface portion 164 of the electronic board 100. More specifically, the axial annular protrusion 126 is located at the bottom end of the through hole 120 and protrudes downwards vertically d relative to the planar surface portion 164 of the electronic board 100, the vertical distance d not exceeding 30 μm. Correspondingly, the axial annular protrusion 128 is located at the top end of the through hole 120 and protrudes upwards vertically d relative to the planar surface portion 166 of the electronic board 100, the vertical distance D not exceeding 20 μm. However, the vertical distances d and D can be greater than 0.5 μm. Therefore, due to the reference Figure 1 The manufacturing process described can produce rounded burrs with very small vertical extensions.

[0120] Furthermore, the electronic board 100 includes radially annular protrusions 130, 132, and 134 projecting inwardly from the sidewall 118 of the stack 102. The central radially annular protrusion 130 is located inside the through-hole 120, particularly at a height corresponding to the electrical insulation layer structure 104. The outer radially annular protrusions 132 and 134 are located at the ends of the through-hole 120. More specifically, the radially annular protrusion 132 is located at the bottom end of the through-hole 120 and is integrally formed with the axially annular protrusion 126. Correspondingly, the radially annular protrusion 134 is located at the top end of the through-hole 120 and is integrally formed with the axially annular protrusion 128. The outer axially annular protrusions 126 and 128 and the central radially annular protrusion 130 are distinct from each other.

[0121] from Figure 2 As can be seen, the axial annular protrusions 126, 128 and the radial annular protrusions 132, 134 are partially defined by the corresponding electrically conductive layer structures 106, 108, and partially by the plating layer 122. Conversely, the radial annular protrusion 130 is partially defined by the electrically insulating layer structure 104 and partially by the plating layer 122. Any of the axial annular protrusions 126, 128 and the radial annular protrusions 130, 132, 134 may have or may not have a substantially constant cross-section along the circumferential portion of the through hole 120.

[0122] according to Figure 2Each of the radial annular protrusions 130, 132, and 134 forms a partial bottleneck portion of the through-hole 120, such that the through-hole 120 locally widens between adjacent annular protrusions of the annular protrusions 130, 132, and 134. Furthermore, the through-hole 120 has an inner diameter that increases from the axial intermediate portion 136 of the electrical insulating layer structure 104 along the axial direction 162 toward each of the electrically conductive layer structures 106 and 108, and an inner diameter that decreases further away from the electrical insulating layer structure 104 along the axial direction 162 from the axial intermediate portion 136.

[0123] Still referencing Figure 2 The electrically insulating layer structure 104 has an irregular portion 140 at its circumferential portion extending around the through-hole 120 relative to the corresponding planar main surface 112 of the electrically insulating layer structure 104. In the illustrated embodiment, the irregular portion 140 is a circumferential notch or groove formed in the corner region between the upper main surface 112 and the side surface 170 of the electrically insulating layer structure 104. This irregular portion 140 may be a defect from the mechanical drilling process used to form the through-hole 120. The plating layer 122 may partially fill the irregular portion 140 of the electrically insulating layer structure 104. Another portion of the irregular portion 140 may be filled with the material of the electrically conductive layer structure 108.

[0124] In another embodiment, the plating layer 122 may cover only a portion of the two opposite main surfaces 114, 116 of the stack 102, for example, it may be applied to the surfaces of the stack 102. Figure 2 The reference numeral 168 in the figure terminates at the position corresponding to it. In this configuration, the corresponding axial annular protrusions 126, 128 can form separate protruding islands around the respective ends of the through hole 120.

[0125] Figure 3 A cross-sectional image of an electronic board 100 according to an exemplary embodiment of the present invention is shown. Figure 3 The image was captured from a cross-section of the actual manufactured electronic board 100. (As shown...) Figure 3 As shown, a reference is also shown here. Figure 2 The description includes many features.

[0126] In addition, according to Figure 3 The corresponding portion 138 of the sidewall defines the corresponding through hole 120 and extends between the axial annular protrusions 126, 128 and the corresponding central radial annular protrusion 130, and has a straight shape.

[0127] For example Figure 3As shown, the diameter b of the electrically insulating layer structure 104 is smaller than the diameter B1 of the electrically conductive layer structure 106 including the plating layer 122 located between adjacent through holes 120, 120, and smaller than the diameter B2 of the other electrically conductive layer structure 108 including the plating layer located between adjacent through holes 120, 120. The diameter of the electrically conductive layer structure 106 and the diameter of the other electrically conductive layer structure 108 may be different or the same.

[0128] Figure 4 A cross-sectional image of an electronic board 100 according to an exemplary embodiment of the present invention is shown. Figures 5 to 12 It shows that according to Figure 4 Details of the image of electronic board 100. (Reference) Figure 5 It shows in detail the basis Figure 4 The upper right corner section of the left overlapping portion. This detail shows the radial annular protrusion 134 produced by the mechanical drill bit in both the axial and radial directions. The radial annular protrusion 134 is made more apparent by the applied coating 122. Reference Figure 6 It shows in detail the basis Figure 4 The upper right corner cross-section of the electrically insulating layer structure 104 with an irregular portion 140 on the left side. This can be created during a mechanical drilling process, such that material to be removed and extracted from the borehole may tear off some material from the electrically insulating layer structure 104, thereby creating this irregular portion 140. (See reference...) Figure 7 It shows in detail the basis Figure 4 The lower right corner section of the left stacked portion. Furthermore, the drill bit can shear the electrical insulation layer structure 104 in the stacking direction. Therefore, an angular irregular portion 40 can be formed. (Reference) Figure 8 It shows in detail the basis Figure 4The central section around the electrically insulating layer structure 104 of the left-side stacked portion. Even without considering the included plating layer 122, a radially annular protrusion 130 can be formed by the electrically insulating layer structure 104. Due to the mechanical drilling process, the electrically insulating layer structure 104 can protrude radially outward into the through hole 120. Without being bound by any particular theory, it is currently believed that this may be a result of a relaxation process caused by the material of the electrically insulating layer structure 104 reacting to the shear forces applied by the mechanical drilling process. Furthermore, anchoring structures can be created around reference numeral 140 and correspondingly on the bottom side of the electrically insulating layer structure 104 and between them. This anchoring structure enhances the mechanical integrity of the electronic board 100 as a whole, and this anchoring structure can be created because the material may reduce its viscous behavior due to the thermal shock of the drill bit. The material near the drill bit may experience elevated temperatures and may therefore begin to polymerize, crosslink, and / or cure. In addition, the drill bit shears the electrically insulating layer structure 104 toward the drill bit. The material behind the hole may be more flexible and tend to relax back to its initial position after drilling. However, the cured portion may not relax because it may have lost its flexibility due to curing. Therefore, this bottleneck or anchoring structure may be created. (Reference) Figure 9 This further details the data based on... Figure 4 The upper right corner section of the left-side overlapping portion. (Reference) Figure 10 It shows in detail the basis Figure 4 The lower right corner section of the left-side overlapping portion. (Reference) Figure 11 It shows in detail the basis Figure 4 The lower left corner section of the right-side overlapping portion. (Reference) Figure 12 It shows in detail the basis Figure 4 The central section of the right-side stacked portion around the electrical insulation layer structure 104.

[0129] Figure 13 A cross-sectional image of an electronic board 100 according to an exemplary embodiment of the present invention is shown. Figure 13 The cross-section of the three stacked pieces between the two through holes 120 is shown.

[0130] Figure 14 A cross-sectional image of an electronic board 100 according to an exemplary embodiment of the present invention is shown.

[0131] exist Figure 14In the figure, a grinding tool is schematically shown with reference numeral 170. The grinding tool 170 is used to grind the lower main surface of the electronic board 100 or a preform of the electronic board 100. By selectively removing material from the axial annular protrusion 126 on the bottom side of the stack 102 through grinding, a discontinuous plating structure is formed, as indicated by reference numeral 172. Thus, at the circumferential portion of the through hole 120, a portion of the plurality of plating layers 122', 122'' extends discontinuously at the lower main surface 114 of the stack 102. Thus, an edge of the electrically conductive layer structure 106 covered by the plating layer 122 is sharpened, see reference numeral 176.

[0132] Although Figure 14 Although not shown, the corresponding situation may exist for the electrically conductive layer structure 108. Therefore, the edges of each of the electrically conductive layer structures 106 and 108 covered by the plating layer 122 may be sharpened.

[0133] It should be noted that the term "comprising" does not exclude other elements or steps, and "a" or "the" does not exclude a plural. Furthermore, elements described in connection with different embodiments may be combined.

[0134] It should also be noted that the reference numerals in the claims should not be interpreted as limiting the scope of the claims.

[0135] The implementation of this invention is not limited to the preferred embodiments shown in the figures and described above. On the contrary, even in embodiments with different underlying principles, the solutions shown and various variations based on the principles of this invention can be used.

Claims

1. An electronic board (100), wherein, The electronic board (100) includes: The stack (102) includes at least one electrically insulating layer structure (104) and a plurality of electrically conductive layer structures (106, 108), wherein one of the plurality of electrically conductive layer structures (106) is disposed on a main surface (110) of the at least one electrically insulating layer structure (104), and another of the plurality of electrically conductive layer structures (108) is disposed on the opposite main surface (112) of the at least one electrically insulating layer structure (104); A through hole (120) is formed in the stack (102) and is laterally defined by a conductive material; At least one plating layer (122) is disposed on at least a portion of two opposite main surfaces (114, 116) of the stack (102) and on the sidewall (118) of the stack (102); An axial annular protrusion (126, 128) is provided at one end of the through hole (120); and Radial annular protrusions (130, 132, 134) are provided at the sidewall (118) of the stack (102).

2. The electronic board (100) according to claim 1, wherein, The axial annular protrusions (126, 128) are at least partially defined by one electrically conductive layer structure (106) and / or the other electrically conductive layer structure (108) and / or the at least one plating layer (122), and / or wherein, The radial annular protrusions (130, 132, 134) are at least partially defined by one electrically conductive layer structure (106) and / or the other electrically conductive layer structure (108) and / or the at least one plating layer (122).

3. The electronic board (100) according to claim 1, wherein, The axial annular protrusions (126, 128) and / or the radial annular protrusions (130, 132, 134) have a substantially constant cross-section along the circumferential portion of the through hole (120).

4. The electronic board (100) according to claim 1, wherein, The electronic board (100) includes a plurality of through holes (120) in the stack (102), wherein at least one plating layer (122) is disposed on a sidewall (118) of the stack (102) that defines each of the through holes (120), and each through hole (120) has a corresponding axial annular protrusion (126, 128) disposed at one end of the corresponding through hole (120), and each through hole (120) has a corresponding radial annular protrusion (130, 132, 134) disposed on the sidewall (118) of the stack (102) that defines the corresponding through hole (120).

5. The electronic board (100) according to claim 1, wherein, The axial annular protrusions (126, 128) extend from the sidewall (118) of the stack (102).

6. The electronic board (100) according to claim 1, wherein, The at least one plating layer (122) includes a plurality of stacked plating layers (122', 122''), wherein, in particular, the material of the outermost plating layer (122', 122'') is different from the material of one or more of the inner plating layers (122', 122'').

7. The electronic board (100) according to claim 6, wherein, The material includes silver, and / or the additional material includes copper.

8. The electronic board (100) according to claim 1, wherein, The at least one plating layer (122) forms at least a portion of the axial annular protrusions (126, 128) and / or the radial annular protrusions (130, 132, 134). In particular, the at least one plating layer (122) including a seed layer (122') and at least one additional plating layer (122'') located on the seed layer (122') forms at least a portion of the axial annular protrusions (126, 128) and / or the radial annular protrusions (130, 132, 134).

9. The electronic board (100) according to claim 1, wherein, The electrical insulating layer structure (104) has an irregular portion (140) at the circumferential portion extending around the through hole (120) of the electrical insulating layer structure (104) relative to the corresponding planar main surface (112) of the electrical insulating layer structure (104), wherein, in particular, a portion of the at least one plating layer (122) at least partially fills the irregular portion (140) of the electrical insulating layer structure (104).

10. The electronic board (100) according to claim 9, wherein, The irregular portion (140) of the electrical insulating layer structure (104) includes at least one of a circumferential groove, a circumferential thickness variation portion, and / or a groove-peak structure facing the through hole (120).

11. The electronic board (100) according to claim 1, wherein, The diameter (b) of the electrical insulating layer structure (104) is smaller than the diameter (B1) of the electrical conductive layer structure (106) including the at least one plating layer (122), and / or the diameter (b) of the electrical insulating layer structure (104) is smaller than the diameter (B2) of the other electrical conductive layer structure (108) including the at least one plating layer (122).

12. The electronic board (100) according to claim 1, wherein, The electrical insulation layer structure (104) is made of plastic material, specifically, the electrical insulation layer structure (104) is made of polyimide.

13. The electronic board (100) according to claim 1, wherein, The at least one plating layer (122) includes a plurality of plating layers (122', 122''), and wherein, at the circumferential portion of the through hole (120), at least one of the plurality of plating layers (122', 122'') does not extend or extends discontinuously on at least one of the main surfaces (114, 116) of the stack (102).

14. The electronic board (100) according to claim 1, wherein, An edge of one of the plurality of electrically conductive layer structures (106, 108) covered by the at least one plating layer (122) is sharpened, and / or wherein, The edges of each of the corresponding electrically conductive layer structures (106, 108) covered by the at least one plating layer (122) are sharpened.

15. The electronic board (100) according to claim 1, wherein, The electronic board (100) has a corresponding axial annular protrusion (126, 128) at each of the two opposite ends of the through hole (120).

16. The electronic board (100) according to claim 1, wherein, The corresponding axial annular protrusions (126, 128) form separate protruding islands at different through holes in the through hole (120). In particular, the corresponding axial annular protrusions (126, 128) form separate protruding islands around different through holes in the through hole (120).

17. The electronic board (100) according to claim 1, wherein, The radial annular protrusions (130, 132, 134) form the bottleneck of the through hole (120), such that at least a portion of the through hole (120) widens at one or both of the electrical conductive layer structure (106) and the other electrical conductive layer structure (108).

18. The electronic board (100) according to claim 1, wherein, The radial annular protrusions (130, 132, 134) are located at the height level of the stack (102) corresponding to the electrical insulation layer structure (104).

19. The electronic board (100) according to claim 1, wherein, The through hole (120) has an inner diameter that increases from the electrical insulating layer structure (104) along the axial direction toward one or both of the electrical conductive layer structure (106) and the other electrical conductive layer structure (108), and the through hole (120) has an inner diameter that decreases from the axial middle portion (136) further away from the electrical insulating layer structure (104) along the axial direction.

20. The electronic board (100) according to claim 1, wherein, The one electrically conductive layer structure (106) and / or the other electrically conductive layer structure (108) have a thickness of at least 80 μm, and in particular, the one electrically conductive layer structure (106) and / or the other electrically conductive layer structure (108) have a thickness of at least 100 μm.

21. The electronic board (100) according to claim 1, wherein, The electronic board (100) includes additional axial annular protrusions (126, 128) disposed at the opposite end of the through hole (120).

22. The electronic board (100) according to claim 1, wherein, The electronic board (100) includes at least one additional radial annular protrusion (130, 132, 134) disposed at one end or two opposite ends of the through hole (120).

23. A method for manufacturing an electronic board (100), wherein, The method includes: A stack (102) is provided, the stack (102) including at least one electrically insulating layer structure (104) and a plurality of electrically conductive layer structures (106, 108), wherein one of the plurality of electrically conductive layer structures (106) is disposed on a main surface (110) of the at least one electrically insulating layer structure (104), and another electrically conductive layer structure (108) of the plurality of electrically conductive layer structures is disposed on the opposite main surface (112) of the at least one electrically insulating layer structure (104); A through hole (120) is formed in the stacked member (102); At least one plating layer (122) is formed on at least a portion of the two opposite main surfaces (114, 116) of the stack (102) and on the sidewall (118) of the stack (102). An axial annular protrusion (126, 128) is formed at one end of the through hole (120); and A radial annular protrusion (130, 132, 134) is formed at the sidewall (118) of the stack (102).

24. The method according to claim 23, wherein, The method includes forming the through hole (120) in the stack (102) by mechanical drilling.

25. The method according to claim 23, wherein, The method includes forming the through hole (120) in the stack (102) when the stack (102) is disposed between the bottom protective structure (144) and the top protective structure (146).

Images