Circuit board structure

Abstract

The utility model provides a kind of circuit board structure.Circuit board structure includes dielectric layer, first metal layer, second metal layer and support piece.First metal layer is set in dielectric layer or on dielectric layer.Second metal layer is set in dielectric layer, wherein dielectric layer, first metal layer and second metal layer form cavity jointly.Support piece is set in cavity, wherein support piece includes multiple hollow spheres and dielectric material.Dielectric material covers hollow sphere.

Description

Technical Field

[0001] This utility model relates to circuit board structures, and more particularly to a circuit board structure in which a cavity is filled with a supporting material. Background Technology

[0002] As technology evolves, electronic products are required to achieve higher performance. Taking circuit board structures as an example, extremely low dielectric constants (Dk) and dissipation factors (Df) can be obtained by forming cavities within the circuit board structure and placing these cavities as close as possible to the outermost traces. However, cavities are not solid; in other words, the strength of the areas containing cavities may be insufficient. Insufficient strength can cause the circuit board structure to deform during subsequent processes or in use, thereby losing its intended function. Therefore, although existing circuit board structures have gradually met their intended uses, they are not perfect in every aspect. Thus, there is still a need to further improve circuit board structures. Utility Model Content

[0003] According to some embodiments, a circuit board structure is provided. The circuit board structure includes a dielectric layer, a first metal layer, a second metal layer, and a support member. The first metal layer is disposed in or on the dielectric layer. The second metal layer is disposed in the dielectric layer, wherein the dielectric layer, the first metal layer, and the second metal layer together form a cavity. The support member is disposed in the cavity, wherein the support member includes a plurality of hollow spheres and a dielectric material. The dielectric material covers the hollow spheres.

[0004] In some embodiments, the first metal layer is in direct contact with the support.

[0005] In some embodiments, the second metal layer is in direct contact with the support.

[0006] In some embodiments, the hollow sphere includes an outer shell and a filling gas. The filling gas fills the outer shell.

[0007] In some embodiments, the hollow spheres are substantially uniformly distributed in the dielectric material.

[0008] In some embodiments, the outer shell is an irregular sphere.

[0009] In some embodiments, the diameter of each of the hollow spheres falls between 80% and 120% of the average diameter.

[0010] In some embodiments, the hollow sphere occupies at least 20% of the total volume of the support.

[0011] In some embodiments, the circuit board structure further includes a third metal layer, and one or both sides of the support member are in contact with the third metal layer.

[0012] In some embodiments, the first metal layer is located on the dielectric layer, and the thickness of the first metal layer is greater than the thickness of the second metal layer.

[0013] The circuit board structure of this invention can be applied to various types of electronic devices. To make the components and advantages of this invention more apparent and understandable, various embodiments are described below in conjunction with the accompanying drawings for detailed explanation. Attached Figure Description

[0014] When with attachment Figure 1 This invention can be more fully understood from the following detailed description. It is worth noting that, in accordance with industry standard practice, the components are not drawn to scale. In fact, for clarity, the dimensions of each component can be arbitrarily enlarged or reduced.

[0015] Figure 1 This is a top view schematic diagram showing a portion of the circuit board structure according to some embodiments of the present invention.

[0016] Figures 2 to 9 These are cross-sectional schematic diagrams showing the circuit board structure at different formation stages according to some embodiments of the present invention.

[0017] Figure 10 This is a cross-sectional schematic diagram of the circuit board structure according to some other embodiments of the present invention.

[0018] Figure 11 This is a cross-sectional schematic diagram of the circuit board structure according to some other embodiments of the present invention.

[0019] Figure 12 This is a cross-sectional schematic diagram of the circuit board structure according to some other embodiments of the present invention. Detailed Implementation

[0020] The following provides a detailed description of the apparatus according to various embodiments of the present invention. It should be understood that the following description provides many different embodiments for implementing various forms of some embodiments of the present invention. The specific elements and arrangements described below are merely for simple and clear description of some embodiments of the present invention. Of course, these are only examples and not limitations on the present invention. Furthermore, similar and / or corresponding element symbols may be used in different embodiments to identify similar and / or corresponding elements for clear description of the present invention. However, the use of these similar and / or corresponding element symbols is only for simple and clear description of some embodiments of the present invention and does not represent any connection between the different embodiments and / or structures discussed.

[0021] Furthermore, it should be understood that the ordinal numbers used in the specification and claims, such as "first," "second," etc., to modify elements, are not intended to imply any prior ordinal number representing the (or plurality of) elements, nor to represent the order of one element with another, or the order of manufacturing processes. The use of these ordinal numbers is solely to clearly distinguish one named element from another element with the same name. The claims and specification may not use the same terminology; for example, a first element in the specification may be a second element in the claim.

[0022] In some embodiments of this utility model, terms such as "connect," "interconnect," and "bond," unless specifically defined, may refer to two structures in direct contact, or to two structures not in direct contact, wherein another structure is disposed between the two structures. Furthermore, these terms regarding connection and bonding may also include cases where both structures are movable or both structures are fixed. In addition, the terms "electrical connection" or "electrical coupling" include any direct and indirect electrical connection means.

[0023] In this text, the terms "approximately," "about," and "substantially" typically indicate a value or range within 10%, 5%, 3%, 2%, 1%, or 0.5%. The given quantities are approximate; that is, even without specific mention of "approximately," "about," or "substantially," their meaning is implied. The phrase "the range is between the first and second values" indicates that the range includes the first value, the second value, and other values ​​in between. Furthermore, any two values ​​or directions used for comparison may have a certain degree of error. If the first value equals the second value, it implies an error within approximately 10%, 5%, 3%, 2%, 1%, or 0.5%. If the first direction is perpendicular to the second direction, the angle between the first and second directions may be between 80 and 100 degrees. If the first direction is parallel to the second direction, then the angle between the first direction and the second direction can be between 0 degrees and 10 degrees.

[0024] It should be understood that, without departing from the spirit of this utility model, the components in the various embodiments described below can be replaced, reorganized, or combined to complete other embodiments. Components in each embodiment can be arbitrarily combined and used as long as they do not violate the inventive spirit or conflict with it.

[0025] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art. It is understood that such terms, for example, as defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the relevant art and the background or context of this invention, and should not be interpreted in an idealized or overly formal manner, unless specifically defined in embodiments of this invention.

[0026] To achieve extremely low dielectric constants (Dk) and dissipation factors (Df), a large amount of low-dielectric-constant dielectric materials can be used in the circuit board structure. However, this approach significantly increases raw material costs, hindering industry development. Alternatively, some approaches incorporate cavities within the circuit board structure to improve the electrical properties of these areas. However, cavities lack solidity (i.e., they are only filled with gas), resulting in lower mechanical strength for the cavity and its surroundings. During subsequent processing of the circuit board structure (e.g., lamination) or during use (e.g., connection to other components), the cavityd areas may collapse or deform under pressure. This will prevent the circuit board structure from fulfilling its intended function.

[0027] Reference Figure 1 This is a top view schematic diagram showing a portion of the circuit board structure according to some embodiments of the present invention. For example... Figure 1 As shown in the top view, the circuit board structure 1 may include a connection area CA and a main body area MA. Specifically, the main body area MA is used to accommodate various active and / or passive components. The connection area CA is disposed on one side (e.g., the periphery) of the main body area MA and is used for electrically connecting the components in the main body area MA to other electronic devices (not shown). In some embodiments, the main body area MA may include one or more high-speed transmission lines disposed in the dielectric layer. On the other hand, the connection area CA may be a gold finger, which corresponds to a slot for other electronic devices. For example, the connection area CA may include a plurality of connection terminals T, and each connection terminal T includes one or more exposed or disposed in the dielectric layer connection lines.

[0028] To ensure that the high-speed transmission line in the main body region MA and the connection terminal T in the connection region CA meet design requirements (e.g., achieving high-speed transmission and high-speed connection), this invention provides a cavity below (or above) the high-speed transmission line in the main body region MA and / or the connection line in the connection region CA, and fills the cavity with a support material including hollow spheres. This effectively improves electrical properties significantly without significantly reducing mechanical strength. In other words, this invention forms a circuit board structure with excellent dielectric constant and dissipation factor, thereby solving some of the problems mentioned in the prior art. It is worth noting that although the above example uses the high-speed transmission line in the main body region MA and the connection terminal T in the connection region CA, this invention is not limited to this. In other embodiments, the support material including hollow spheres can be applied to any area of ​​the circuit board structure where electrical properties need to be adjusted.

[0029] Reference Figures 2 to 9 These figures, according to some embodiments of the present invention, show cross-sectional schematic diagrams of the circuit board structure at different formation stages. It is worth noting that, for the sake of simplicity and ease of understanding, the figures of the present invention may exaggerate the dimensions of components and the proportions between them. For example, the figures may alter the actual distance or relative relationship between the main body region MA and the connection region CA. Furthermore, the figures of the present invention may omit some components in the circuit board structure, but those skilled in the art will understand that the circuit board structure may also include other common components. For example, the circuit board structure of the present invention may also include various active components, passive components, heat dissipation components, connectors, and / or protective layers, etc., not shown in the figures.

[0030] like Figure 1 As shown, in some embodiments, a core substrate 10 is provided. The core substrate 10 may include a core layer 101 and a metal layer 102, and the metal layer 102 may be disposed on one or both sides of the core layer 101. In some embodiments, the material of the core layer 101 may be or may include a prepreg containing polymeric materials, fibrous materials, or other suitable materials, but the present invention is not limited thereto. For example, the polymeric material may be or may include epoxy resin, polyimide (PI), polypropylene (PP), other suitable polymeric materials, or combinations thereof, but the present invention is not limited thereto. For example, the fibrous material may include carbon fiber, glass fiber, other suitable fibrous materials, or combinations thereof, but the present invention is not limited thereto. In some embodiments, the material of the metal layer 102 may be or may include aluminum (Al), copper (Cu), alloys thereof, or compounds thereof, but the present invention is not limited thereto. In some embodiments, the core substrate 10 is a copper foil substrate.

[0031] In some embodiments, a combination of photolithography and etching processes can be used to give the metal layer 102 a specific conductive pattern. In some embodiments, the photolithography process may include photoresist application (e.g., spin-on coating, lamination), soft baking, mask alignment, exposure, post-exposure baking, photoresist developing, rinsing, drying (e.g., spin-drying and / or hard baking), other suitable photolithography techniques, and / or combinations thereof, but the present invention is not limited thereto. In some embodiments, the etching process may include dry etching, wet etching, other suitable etching processes, or combinations thereof, but the present invention is not limited thereto.

[0032] Following the above steps, dielectric layer 11, metal layer 12, dielectric layer 13, metal layer 14, and dielectric layer 15 are sequentially disposed on metal layer 102 to form a first stack. In some embodiments, the materials of dielectric layer 11, dielectric layer 13, and / or dielectric layer 15 may be epoxy resin, polyimide (PI), build-up material (ABF), other suitable polymer materials, or combinations thereof, but the present invention is not limited thereto. In some embodiments, dielectric layer 11, dielectric layer 13, and / or dielectric layer 15 may be formed by lamination, coating, other suitable processes, or combinations thereof, but the present invention is not limited thereto. In some embodiments, the materials, thicknesses, and arrangement of dielectric layer 11, dielectric layer 13, and dielectric layer 15 may be the same or different to correspond to different design requirements.

[0033] In some embodiments, the material of metal layer 12 and / or metal layer 14 may be aluminum (Al), copper (Cu), alloys thereof, or compounds thereof, but the present invention is not limited thereto. In some embodiments, metal layer 12 and / or metal layer 14 may be formed by lamination, deposition, other suitable processes, or combinations thereof, but the present invention is not limited thereto. For example, deposition processes may include electroplating, chemical plating, physical vapor deposition (PVD), chemical vapor deposition (CVD), other suitable processes, or combinations thereof, but the present invention is not limited thereto. In some embodiments, metal layer 12 and / or metal layer 14 may also have a specific conductive pattern by a combination of photolithography and etching processes. In some embodiments, the material, thickness, and arrangement of metal layer 12 and metal layer 14 may be the same or different to correspond to different design requirements.

[0034] Following the steps described above, a first opening OP1 is formed in the main body region MA of the first stack. Specifically, the first opening OP1 penetrates the dielectric layer 11, metal layer 12, dielectric layer 13, metal layer 14, and dielectric layer 15, and exposes the upper surface of the metal layer 102. In some embodiments, the first opening OP1 can be formed by laser drilling, etching drilling, mechanical drilling, other suitable processes, or combinations thereof, but the present invention is not limited thereto. In some embodiments, the metal layer 102 can also serve as an etch stop layer. For example, the material of the metal layer 102 can be different from that of the metal layers 12 and 14 to have different etch selectivity ratios. In some embodiments, the metal layer 102 can also be made thick enough to significantly extend the time for the drilling process to remove the metal layer 102, thereby improving the drilling process margin.

[0035] It is worth mentioning that, although Figure 2 An embodiment is shown in which a first opening OP1 is formed on the upper side of the core substrate 10, but the present invention is not limited thereto. In other embodiments, the first opening OP1 may also be formed on both the upper and lower sides of the core substrate 10. Furthermore, the two first openings OP1 may completely overlap, partially overlap, or not overlap at all in the normal direction of the core substrate 10 to meet different design requirements. On the other hand, although Figure 2The illustration shows an embodiment where the first opening OP1 penetrates through dielectric layer 11, metal layer 12, dielectric layer 13, metal layer 14, and dielectric layer 15, but the present invention is not limited thereto. In other embodiments, the first opening OP1 may arbitrarily penetrate one or more of dielectric layer 11, metal layer 12, dielectric layer 13, metal layer 14, and dielectric layer 15 to meet different design requirements.

[0036] like Figure 3 As shown, a support material is filled into the first opening OP1 to form a support member 16. In some embodiments, the support material or the formed support member 16 may include a dielectric material 161 and a plurality of hollow spheres 162. The hollow spheres 162 are covered by the dielectric material 161 and are uniformly distributed within the dielectric material 161. In some embodiments, the hollow spheres 162 include a shell 1621 and a filling gas 1622. The shell 1621 is used to contain the filling gas 1622. Specifically, the dielectric material 161, after curing, can be used to improve the mechanical strength of the area where the support member 16 is located. On the other hand, the hollow spheres 162 include a combination of a solid shell and a gas core, which can be used to adjust the overall dielectric constant (Dk) and dissipation factor (Df) of the support member 16. In other words, this invention adjusts various parameters (e.g., material, shape, composition, gas pressure, etc.) of the dielectric material 161 and the hollow spheres 162 to give the support member 16 a certain degree of mechanical strength while producing a cavity-like effect.

[0037] In some embodiments, support material can be filled into the first opening OP1 by printing, inkjet printing, extrusion, other suitable processes, or combinations thereof, and the support material can be cured by heating to form the support member 16, but the present invention is not limited thereto. In some embodiments, the support material can be made to protrude (or overflow) from the first opening OP1 to ensure that the support material completely fills the first opening OP1. In other words, the upper surface of the support material (or support member 16) is not coplanar with the upper surface of the dielectric layer 15.

[0038] In some embodiments, the dielectric constant (Dk) of dielectric material 161 is between 1.5 and 3, but the present invention is not limited thereto. For example, the dielectric constant of dielectric material 161 may be 1.5, 1.75, 2.0, 2.5, 3, or any value or range between the above values, but the present invention is not limited thereto. In some embodiments, the dissipation factor (Df) of dielectric material 161 is less than 0.002. For example, the dissipation factor of dielectric material 161 may be 0.0015, 0.001, 0.0005, 0.00025, 0.0001, substantially 0, or any value or range between the above values, but the present invention is not limited thereto.

[0039] In some embodiments, the dielectric material 161 may include ink, such as epoxy resin ink, polyimide ink, photo-imageable ink, other suitable inks, or combinations thereof, but the present invention is not limited thereto. In some embodiments, the dielectric material 161 is designed to have toughness to withstand the stress caused by the fracture of the hollow sphere 162, thereby reducing its own risk of fracture or preventing fracture.

[0040] In some embodiments, the hollow sphere 162 may be a spherical sphere, an elliptical sphere, an irregular sphere, a triangular pyramid, a triangular prism, a polygonal prism, or other suitable shape, but the present invention is not limited thereto. In some embodiments, the plurality of hollow spheres 162 may have different shapes. For example, some of the hollow spheres 162 may be spherical, while others may be irregular spheres. In some embodiments, the diameters of the plurality of hollow spheres 162 are similar or the same, but the present invention is not limited thereto. For example, the diameter of each hollow sphere 162 falls between 80% and 120% of the average diameter.

[0041] In some embodiments, the hollow sphere 162 occupies at least 20% of the total volume of the support member 16, but the present invention is not limited thereto. For example, the hollow sphere 162 occupies 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 80%, or any value or range between the above values ​​in the total volume of the support member 16. When the hollow sphere 162 occupies too small a portion of the total volume of the support member 16, the function of reducing the dielectric constant and dissipation factor may not be achieved. Conversely, when the hollow sphere 162 occupies too large a portion of the total volume of the support member 16, the mechanical strength of the support member 16 may be insufficient.

[0042] In some embodiments, the hollow spheres 162 may be formed by: coating a gas with a binder; baking a resin to polymerize bonds and form voids therein; injecting air into a polymer substrate; foaming a polymer substrate; other suitable methods; or combinations thereof, but the present invention is not limited thereto. In some embodiments, after the hollow spheres 162 are formed, hollow spheres 162 that are too large or too small may be removed by means of a device such as a filter or sieve, so that the volume of each hollow sphere 162 remains substantially the same.

[0043] In some embodiments, the outer shell 1621 of the hollow sphere 162 may include a hydrophilic material to be more uniformly dispersed in a dielectric material 161 such as ink. In some embodiments, the outer shell 1621 of the hollow sphere 162 is designed to be elastic to reduce the risk of breakage or prevent breakage when subjected to high or low temperature changes or external pressure shocks.

[0044] In some embodiments, the filling gas 1622 of the hollow sphere 162 may include air, pure gas, inert gas, other suitable gases, or combinations thereof, but the present invention is not limited thereto. For example, pure gas may include oxygen, nitrogen, or combinations thereof. Inert gas may include helium, neon, argon, or combinations thereof. In some embodiments, when the temperature is greater than or equal to 10°C and less than or equal to 40°C, the filling gas 1622 has a first gas pressure; when the temperature is greater than 40°C and less than or equal to 120°C, the filling gas 1622 has a second gas pressure, and the ratio of the second gas pressure to the first gas pressure is less than 2. In other words, when the filling gas 1622 is subjected to high and low temperature shocks, the changed gas pressure can be maintained within 0.5 to 2 times the initial gas pressure, so as to reduce the risk of rupture of the outer shell 1621 or prevent the outer shell 1621 from rupturing.

[0045] like Figure 4 As shown, following the above steps, the support member 16 protruding from the first opening OP1 is removed so that the upper surface of the support member 16 is coplanar with the upper surface of the dielectric layer 15. In some embodiments, a portion of the support member 16 may be removed by dry grinding / dry polishing, laser ablation, wet etching, other suitable methods, or combinations thereof, but the present invention is not limited thereto.

[0046] like Figure 5 As shown, following the steps described above, a metal layer 17 is formed on the dielectric layer 15. In some embodiments, the material of the metal layer 17 may be aluminum (Al), copper (Cu), their alloys, or compounds, but the present invention is not limited thereto. In some embodiments, the metal layer 17 may be formed by lamination, deposition, other suitable processes, or combinations thereof, but the present invention is not limited thereto. In some embodiments, a combination of photolithography and etching processes may be used to give the metal layer 17 a specific conductive pattern. In some embodiments, the material, thickness, and arrangement of the metal layer 17 may be the same as or different from those of the metal layer 12 or the metal layer 14 to correspond to different design requirements. In some embodiments, a combination of photolithography and etching processes may be used to give the metal layer 17 a specific conductive pattern.

[0047] After the metal layer 17 is formed, the upper surface of the support 16 directly contacts the metal layer 17, and the lower surface directly contacts the metal layer 102. When one or both of the metal layers 102 and 17 are used as high-speed transmission lines, extremely low dielectric constant (Dk) and dissipation factor (Df) can be achieved in this region by means of the support 16, which is disposed above or below the metal layer and includes a large amount of gas (i.e., hollow spheres 162). In addition, compared with cavities without supporting material, the support 16 also has sufficient mechanical strength to withstand subsequent processes or applications. Therefore, the present invention, through the above-described configuration, satisfies the electrical characteristics of the high-speed transmission line in the main body region MA, while significantly improving the mechanical strength of the overall device.

[0048] like Figure 6 As shown, following the above steps, a dielectric layer 18 is disposed on the metal layer 17 to form a second stack. In some embodiments, the dielectric layer 18 may have the same or different materials, thicknesses, and arrangements as the dielectric layers (e.g., dielectric layer 11, dielectric layer 13, and dielectric layer 15) to correspond to different design requirements.

[0049] Following the steps described above, a second opening OP2 is formed in the connection region CA of the second stack. Specifically, the second opening OP2 penetrates the dielectric layer 13, metal layer 14, dielectric layer 15, metal layer 17, and dielectric layer 18, and exposes the upper surface of the metal layer 12. In some embodiments, the second opening OP2 can be formed by laser drilling, etch drilling, mechanical drilling, other suitable processes, or combinations thereof, but the present invention is not limited thereto. In some embodiments, the metal layer 12 can also serve as an etch stop layer. For example, the material of the metal layer 12 can be different from that of the metal layers 14 and 17 to have different etch selectivity ratios. In some embodiments, the metal layer 12 can also be made thick enough to significantly extend the time for the drilling process to remove the metal layer 12, thereby improving the drilling process margin.

[0050] It is worth mentioning that, although Figure 6 The illustration shows an embodiment in which second openings OP2 are formed on both sides of the core substrate 10, and the two second openings OP2 completely overlap in the normal direction of the core substrate 10, but the present invention is not limited thereto. In other embodiments, the two second openings OP2 may partially overlap or not overlap at all in the normal direction of the core substrate 10 to meet different design requirements. Furthermore, the second opening OP2 may also be formed on one side of the core substrate 10, without forming the second opening OP2 on the other side. On the other hand, although Figure 6The illustration shows an embodiment where the second opening OP2 penetrates through dielectric layer 13, metal layer 14, dielectric layer 15, metal layer 17, and dielectric layer 18, but the present invention is not limited thereto. In other embodiments, the second opening OP2 may arbitrarily penetrate one or more of dielectric layer 13, metal layer 14, dielectric layer 15, metal layer 17, and dielectric layer 18 to meet different design requirements.

[0051] like Figure 7 As shown, following the steps above, support material is filled into the second opening OP2 to form a support member 19. In some embodiments, the support material or the formed support member 19 may include a dielectric material 191 and a plurality of hollow spheres 192. The hollow spheres are covered by the dielectric material 191 and are substantially uniformly distributed within the dielectric material 191. In some embodiments, the hollow spheres 192 include a shell 1921 and a filling gas 1922. The support material and the formed support member 19 here may be similar to or the same as the support material and the formed support member 16 described above. In other words, the dielectric material 191 may be similar to or the same as the dielectric material 161, and the hollow spheres 192 may be similar to or the same as the hollow spheres 162. Therefore, detailed descriptions of the arrangement and detailed structure can be found above and will not be repeated here.

[0052] like Figure 8 As shown, the support member 19 protruding from the second opening OP2 is removed so that the upper surface of the support member 19 is coplanar with the upper surface of the dielectric layer 18. In some embodiments, a portion of the support member 19 may be removed by dry polishing, laser processing, wet etching, other suitable methods, or combinations thereof, but the present invention is not limited thereto.

[0053] like Figure 9 As shown, following the above steps, a metal layer 20 is formed on the dielectric layer 18 to obtain the circuit board structure 1. In some embodiments, the material of the metal layer 20 may be aluminum (Al), copper (Cu), their alloys or compounds, but the present invention is not limited thereto. In some embodiments, the metal layer 20 may be formed by lamination, deposition, other suitable processes or combinations thereof, but the present invention is not limited thereto. In some embodiments, the metal layer 20 may also have a specific conductive pattern by a combination of photolithography and etching processes. In some embodiments, the material, thickness, and arrangement of the metal layer 20 may be the same as or different from those of the aforementioned metal layers (e.g., metal layer 12, metal layer 14 or metal layer 17) to correspond to different design requirements. In some embodiments, when the metal layer 20 is used as an electrical connection structure (e.g., a connection terminal T), the thickness of the metal layer 20 may be significantly greater than the thickness of the aforementioned metal layers (e.g., metal layer 12, metal layer 14 or metal layer 17) to enhance the wear resistance of the metal layer 20. Alternatively, a thicker metal layer 20 may also improve the connection stability as a connection terminal.

[0054] After the metal layer 20 is formed, the upper surface of the support 19 directly contacts the metal layer 20, and the lower surface directly contacts the metal layer 12. When one or both of the metal layers 12 and 20 are used as connection terminals, extremely low dielectric constant (Dk) and dissipation factor (Df) can be achieved in this region by the support 19, which is disposed above or below it and includes a large amount of gas (i.e., hollow spheres 192). In addition, compared with cavities without supporting material, the support 19 also has sufficient mechanical strength to withstand subsequent processes or applications.

[0055] It is worth mentioning that although the above describes a circuit board structure with ten layers (i.e., metal layers 102, 12, 14, 17, and 20 located on the upper and lower sides of the core layer 101), the present invention is not limited thereto. The supporting material and the formed supporting members (e.g., supporting member 16 and supporting member 19) can be applied to circuit board structures with different numbers of layers, or to circuit board structures that are asymmetrical vertically or horizontally.

[0056] Therefore, for ease of understanding, the metal layers on the upper and lower sides of the support member can be defined as the first metal layer and the second metal layer, respectively. In this case, the circuit board structure may include a dielectric layer, a first metal layer, a second metal layer, and a support member. The first metal layer is disposed in or on the dielectric layer. The second metal layer is disposed in the dielectric layer, wherein the dielectric layer, the first metal layer, and the second metal layer together form a cavity. The support member is disposed in the cavity, wherein the support member includes a plurality of hollow spheres and a dielectric material. The dielectric material covers the hollow spheres. In some embodiments, the metal layers on the left and right sides of the support member can be defined as the third metal layer, and one or both sides of the support member are in contact with the third metal layer.

[0057] by Figure 9 Taking an example, in the main body region MA, metal layer 17 serves as the first metal layer above the support member 16, metal layer 102 serves as the second metal layer below the support member 16, and metal layers 12 and 14 serve as the third metal layers on both sides of the support member 16. On the other hand, in the connection region CA, metal layer 20 serves as the first metal layer above the support member 19, metal layer 12 serves as the second metal layer below the support member 19, and metal layers 14 and 17 serve as the third metal layers on both sides of the support member 19. Furthermore, in the connection region CA, the thickness of metal layer 20, which serves as the first metal layer, can be greater than that of metal layer 12, which serves as the second metal layer.

[0058] It is worth mentioning that, although Figure 9The illustration shows an embodiment where metal layer 102 and / or metal layer 12 serves as the second metal layer, but the present invention is not limited thereto. In other embodiments, other support members may be provided below metal layer 102 and / or metal layer 12 to form a stacked support member configuration. In other words, metal layer 102 and / or metal layer 12 can serve as both the second and first metal layers. Similarly, metal layer 12, metal layer 14, or metal layer 17, which serve as the third metal layer, can also be used individually or simultaneously as the first or second metal layer.

[0059] In addition, the concept of support components can also be applied to specific areas of a circuit board structure. (See reference...) Figure 10 This is a cross-sectional schematic diagram of a circuit board structure according to some embodiments of the present invention. As shown, the circuit board structure includes a dielectric layer 21, a metal layer 22, a metal layer 23, a metal layer 24, and a support member 25. Specifically, the metal layer 22 is configured as at least one signal line, or as at least one pair of differential signal lines. The metal layer 23 is configured as a first reference ground plane. The metal layer 24 is configured as a second reference ground plane. The support member 25 is disposed in the cavity formed by the dielectric layer 21, the metal layer 22, and the metal layer 23, and the support member 25 includes a dielectric material 241 and a hollow sphere 252, wherein the hollow sphere 252 includes a shell 2521 and a filling gas 2522. In this embodiment, the metal layer 23 serves as the first metal layer and contacts the upper surface of the support member 25, and the metal layer 22 serves as the second metal layer and contacts the lower surface of the support member 25.

[0060] Reference Figure 11 This is a cross-sectional schematic diagram of a circuit board structure according to some embodiments of the present invention. Figure 10 Compared to the previous embodiment, the circuit board structure further includes a metal layer 26, which is located on at least one side of the support 25. The metal layer 26 is configured as a third reference ground plane, which is coplanar (e.g., coplanar with the lower surface) of the metal layer 22, which serves as a second metal layer. In this embodiment, the metal layer 23 serves as a third metal layer and contacts the side surface of the support 25.

[0061] Reference Figure 12 This is a cross-sectional schematic diagram of a circuit board structure according to some embodiments of the present invention. Figure 11 Compared to the previous embodiment, the circuit board structure is obtained by stacking multiple circuit board structures. In other words, the two copper foil substrates can be processed separately as described above to form two... Figure 11The circuit board structure shown is then used to connect the two circuit board structures with adhesive layer 27. In this way, the following can be obtained: Figure 12 The circuit board structure is shown. In some embodiments, the material of the adhesive layer 27 may be the same as or similar to the various dielectric layers described above, and will not be repeated here.

[0062] In summary, this invention provides a circuit board structure in which a cavity is provided below (or above) high-speed transmission lines and / or connecting lines, and the cavity is filled with a supporting material including hollow spheres. This effectively improves electrical properties significantly without substantially reducing mechanical strength. In other words, this invention forms a circuit board structure with excellent dielectric constant and dissipation factor, thereby solving some of the problems mentioned in the prior art.

[0063] The above outlines several embodiments to enable those skilled in the art to better understand the viewpoints of the present invention. Those skilled in the art should understand that other processes and structures can be designed or modified based on the embodiments of the present invention to achieve the same purpose and / or advantages as the embodiments described herein. Those skilled in the art should also understand that such equivalent processes and structures do not depart from the spirit and scope of the present invention, and that various changes, substitutions, and replacements can be made without departing from the spirit and scope of the present invention.

[0064] [Symbol Explanation] 1: Circuit board structure 10: Core substrate 101: Core Layer 102, 12, 14, 17, 20, 22, 23, 24, 26: Metallic layers 11, 13, 15, 18, 21: Dielectric layers 16, 19, 25: Support components 161, 191, 241: Dielectric materials 162, 192, 252: Hollow sphere 1621, 1921, 2521: Outer shell 1622, 1922, 2522: Filling gas 27: Adhesive layer CA: Link Area MA: Main Region OP1: First opening OP2: Second opening T: Connecting terminal.

Claims

1. A circuit board structure, characterized in that, include: Dielectric layer; A first metal layer is disposed in or on the dielectric layer; A second metal layer is disposed in the dielectric layer, wherein the dielectric layer, the first metal layer and the second metal layer together form a cavity; as well as A support member is disposed in the cavity, wherein the support member includes: Multiple hollow spheres; as well as Dielectric material is used to coat the plurality of hollow spheres.

2. The circuit board structure according to claim 1, characterized in that, The first metal layer is in direct contact with the support member.

3. The circuit board structure according to claim 1, characterized in that, The second metal layer is in direct contact with the support.

4. The circuit board structure according to claim 1, characterized in that, The plurality of hollow spheres include: The outer casing; and A filling gas is used to fill the outer casing.

5. The circuit board structure according to claim 4, characterized in that, The plurality of hollow spheres are substantially uniformly distributed in the dielectric material.

6. The circuit board structure according to claim 4, characterized in that, The outer shell is an irregular sphere.

7. The circuit board structure according to claim 1, characterized in that, The diameter of each of the plurality of hollow spheres falls between 80% and 120% of the average diameter.

8. The circuit board structure according to claim 1, characterized in that, The plurality of hollow spheres occupy at least 20% of the total volume of the support.

9. The circuit board structure according to claim 1, characterized in that, The circuit board structure also includes a third metal layer, and one or both sides of the support member are in contact with the third metal layer.

10. The circuit board structure according to claim 1, characterized in that, The first metal layer is located on the dielectric layer, and the thickness of the first metal layer is greater than the thickness of the second metal layer.

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