Circuit board structure
By combining soft and hard materials into a core stacked circuit board structure, the problems of substrate breakage and warping caused by hard materials are solved, achieving high-strength and low-cost circuit board manufacturing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- UNIMICRON TECH CORP
- Filing Date
- 2025-04-18
- Publication Date
- 2026-04-28
AI Technical Summary
When existing circuit board structures use rigid materials such as glass as the core layer, the substrate is prone to cracking or warping, resulting in poor yield and difficulty in controlling manufacturing costs.
A core stack of soft and hard materials is used as the main substrate, and the core is connected by an adhesive layer and a vertical conductive structure to form a composite circuit board structure, which can alleviate the deformation problem caused by uneven thermal stress.
While maintaining high mechanical strength, it avoids the warping or deformation problems that occur when using rigid substrates alone, thereby improving the yield of circuit boards and reducing manufacturing costs.
Smart Images
Figure CN224178358U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to circuit board structures, and more particularly to a circuit board structure having a core stack composed of composite materials. Background Technology
[0002] With the widespread use of electronic products, these products are required to possess superior properties. In circuit board structures that use rigid materials such as glass as the core layer, substrate breakage or warping frequently occurs. These problems lead to poor yield rates and make manufacturing costs difficult to control. Therefore, although existing circuit board structures have gradually met their intended uses, they are not perfect in every aspect. Thus, further improvements to circuit board structures are still needed. Utility Model Content
[0003] According to some embodiments, a circuit board structure is provided. The circuit board structure includes a core stack and a first circuit stack. The core stack includes a flexible substrate, a first rigid substrate, and a second rigid substrate. The flexible substrate has a first surface and a second surface opposite to each other. The first rigid substrate is disposed on the first surface. The second rigid substrate is disposed on the second surface. The first circuit stack is disposed on one side of the core stack and includes a first dielectric layer and a first circuit layer. The first dielectric layer is disposed on the first rigid substrate. The first circuit layer is disposed on or within the first dielectric layer.
[0004] In some embodiments, the core stack further includes a first adhesive layer and a second adhesive layer. The first adhesive layer is disposed between the first rigid substrate and the flexible substrate. The second adhesive layer is disposed between the second rigid substrate and the flexible substrate.
[0005] In some embodiments, the core stack further includes a first vertical conductive structure. The first vertical conductive structure is disposed within the flexible substrate, the first rigid substrate, and the second rigid substrate.
[0006] In some embodiments, the first vertical conductive structure includes a first portion, a second portion, and a third portion. The first portion is located in a flexible substrate and has a first maximum aperture. The second portion is located in a first rigid substrate and has a second maximum aperture. The third portion is located in a second rigid substrate and has a third maximum aperture. The first maximum aperture is smaller than both the second and third maximum apertures.
[0007] In some embodiments, the second portion further has a first minimum aperture, the third portion further has a second minimum aperture, and the first maximum aperture is smaller than the first minimum aperture and the second minimum aperture.
[0008] In some embodiments, the first circuit stack further includes a third vertical conductive structure. The third vertical conductive structure passes through the first dielectric layer and is electrically connected to the first vertical conductive structure or the first circuit layer.
[0009] In some embodiments, the first circuit stack further includes a third rigid substrate. The third rigid substrate is disposed on or in the first dielectric layer.
[0010] In some embodiments, the circuit board structure further includes a second circuit stack. The second circuit stack is disposed on the other side of the core stack and includes a second dielectric layer and a second circuit layer. The second dielectric layer is disposed on a second rigid substrate. The second circuit layer is disposed on the second dielectric layer.
[0011] In some embodiments, the second circuit stack further includes a second vertical conductive structure. The second vertical conductive structure passes through the second dielectric layer and is electrically connected to the first vertical conductive structure or the second circuit layer.
[0012] In some embodiments, the second circuit stack further includes a fourth rigid substrate. The fourth rigid substrate is disposed on or in the second dielectric 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 detail with reference to the accompanying drawings. 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] Figures 1 to 9 These are cross-sectional schematic diagrams showing different stages of the manufacturing process of the circuit board structure according to some embodiments of the present invention.
[0016] Figure 10 This is a cross-sectional schematic diagram of a circuit board structure according to some other embodiments of the present invention. Detailed Implementation
[0017] 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 association between the different embodiments and / or structures discussed.
[0018] 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 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 claims.
[0019] 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, with other structures disposed between them. Furthermore, these terms may include situations where both structures are movable or both are fixed. Additionally, the terms "electrical connection" or "electrical coupling" include any direct or indirect electrical connection means.
[0020] In this text, the terms "approximately," "about," and "substantially" typically indicate that a given value or range is within 10%, 5%, 3%, 2%, 1%, or 0.5%. The given quantity is an approximate quantity; that is, even without specific mention of "approximately," "about," or "substantially," the meaning of "approximately," "about," or "substantially" is implied. The phrase "the range is between the first value and the second value" 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% between the first and second values. 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.
[0021] 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 spirit of the utility model or conflict with it.
[0022] 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.
[0023] Glass possesses a low coefficient of thermal expansion (CTE), high insulation, and low loss, making it a frequent primary substrate in circuit board structures. However, the high rigidity of glass substrates also presents some challenges. For instance, when the circuit board structure is asymmetrical (e.g., one side has a larger total volume of circuit layers than the other, or one side is thicker than the other), the structure may experience unbalanced contraction torques due to thermal stress, leading to deformations such as warping. Furthermore, compared to flexible substrates, glass substrates are less likely to release accumulated stress. In other words, when subjected to stress, glass substrates have a higher probability of permanent deformation or even breakage.
[0024] Therefore, this invention provides a circuit board structure that combines soft and hard materials into a core stack, and uses this core stack as the main substrate. In this way, the circuit board structure of this invention maintains high strength while avoiding some problems that may arise from using a hard substrate alone as the main substrate. It is worth noting that although glass was used as an example of a hard substrate above, this invention is not limited to this. For those skilled in the art, a hard substrate can include any substrate with relatively high hardness (or expressed as a modulus of elasticity). Therefore, this invention can employ various hard substrates, including but not limited to glass.
[0025] Reference Figures 1 to 8 These are cross-sectional schematic diagrams showing different stages of the manufacturing process of the circuit board structure according to some embodiments of the present invention. It is worth noting that, for the sake of simplicity and ease of understanding, the dimensions of components and the proportions between them may be exaggerated in the drawings of the present invention. Furthermore, some components in the circuit board structure may be omitted in the drawings of the present invention, 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 drawings.
[0026] like Figure 1 As shown, a flexible substrate 100 is provided, and the flexible substrate 100 has a first surface 100A and a second surface 100B opposite to each other. In some embodiments, the flexible substrate 100 may include a dielectric material with a flexural modulus less than 15 GPa, but the present invention is not limited thereto. For example, the flexural modulus of the flexible substrate 100 may be below 10 GPa, for example, between 1.5 GPa and 4 GPa. In some embodiments, the material of the flexible substrate 100 may be or include polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), liquid crystal polymer (LCP), thermoplastic polyurethane (TPU), thermoplastic elastomer (TPE), other suitable materials or combinations thereof, but the present invention is not limited thereto. In some embodiments, the flexible substrate 100 may be a multilayer structure to meet different design requirements.
[0027] In some embodiments, the thickness t1 of the flexible substrate 100 is between 10 μm and 500 μm, but the present invention is not limited thereto. For example, the thickness t1 can be 10 μm, 20 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 400 μm, 500 μm, or any value or range between the above values.
[0028] like Figure 2 As shown, following the above steps, a first adhesive layer 101 is formed on the first surface 100A of the flexible substrate 100, and a second adhesive layer 102 is formed on the second surface 100B of the flexible substrate 100. Specifically, the first adhesive layer 101 is used to bond the flexible substrate 100 to the first rigid substrate 103 to be formed, and the second adhesive layer 102 is used to bond the flexible substrate 100 to the second rigid substrate 104 to be formed. In some embodiments, the first adhesive layer 101 may also have physical properties (e.g., elastic modulus, coefficient of thermal expansion, dielectric constant, etc.) between the flexible substrate 100 and the first rigid substrate 103, to serve as a buffer layer between them. Similarly, the second adhesive layer 102 may also have physical properties (e.g., elastic modulus, coefficient of thermal expansion, dielectric constant, etc.) between the flexible substrate 100 and the second rigid substrate 104, to serve as a buffer layer between them.
[0029] In some embodiments, the materials of the first adhesive layer 101 and / or the second adhesive layer 102 may include an Ajinomoto build-up film (ABF), other suitable materials, or combinations thereof, but the present invention is not limited thereto. In some embodiments, the materials, thicknesses, shapes, other parameters, or combinations thereof of the first adhesive layer 101 and the second adhesive layer 102 may be the same, similar, or different to meet different design requirements.
[0030] like Figure 3 As shown, following the above steps, a first rigid substrate 103 is disposed on the first adhesive layer 101, and a second rigid substrate 104 is disposed on the second adhesive layer 102 to form a core stack 10. In other words, the core stack 10 formed by the above steps has a sandwich structure, which includes a flexible substrate 100 located at the center, adhesive layers (i.e., the first adhesive layer 101 and the second adhesive layer 102) located on both sides of the flexible substrate 100, and rigid substrates (i.e., the first rigid substrate 103 and the second rigid substrate 104) located on the adhesive layers. For example, the first rigid substrate 103 and the second rigid substrate 104 can be attached to the first adhesive layer 101 and the second adhesive layer 102 respectively by a pressing process to form the core stack 10, but the present invention is not limited thereto.
[0031] In some embodiments, the first rigid substrate 103 and / or the second rigid substrate 104 may comprise a dielectric material with an elastic modulus greater than 50 GPa, but the present invention is not limited thereto. For example, the elastic modulus of the first rigid substrate 103 and / or the second rigid substrate 104 may be above 10 GPa, for example, between 15 GPa and 20 GPa, or up to 70 GPa and 90 GPa. In some embodiments, the first rigid substrate 103 and / or the second rigid substrate 104 may be or may comprise: a glass substrate, such as borosilicate glass (BSG), quartz glass, or alkali-free glass; a flame retardant grade 4 glass fiber reinforced epoxyresin laminate (FR4); other suitable materials or combinations thereof, but the present invention is not limited thereto.
[0032] In some embodiments, the materials of the flexible substrate 100 and the first rigid substrate 103 can be selected based on the differences in their physical properties (e.g., modulus of elasticity, coefficient of thermal expansion, dielectric constant, etc.) to make them more physically compatible. Similarly, the materials of the flexible substrate 100 and the second rigid substrate 104 can be selected based on the differences in their physical properties (e.g., modulus of elasticity, coefficient of thermal expansion, dielectric constant, etc.) to make them more physically compatible. Of course, suitable first rigid substrate 103 and / or second rigid substrate 104 can also be selected based on the subsequent circuit stack-up.
[0033] In some embodiments, the thickness t2 of the first rigid substrate 103 and / or the thickness t3 of the second rigid substrate 104 are between 10 μm and 500 μm, but the present invention is not limited thereto. For example, the thickness t2 and / or the thickness t3 can be 10 μm, 20 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 400 μm, 500 μm, or any value or range between the above values. When the thickness t2 of the first rigid substrate 103 and / or the thickness t3 of the second rigid substrate 104 is too large, it may be detrimental to subsequent drilling processes (e.g., the required drilling time is too long). Conversely, when the thickness t2 of the first rigid substrate 103 and / or the thickness t3 of the second rigid substrate 104 is too small, it may result in insufficient strength of the circuit board structure.
[0034] In some embodiments, the ratio between thickness t1 and thickness t2 is between 1:3 and 3:1, but the present invention is not limited thereto. In some embodiments, the ratio between thickness t1 and thickness t3 is between 1:3 and 3:1, but the present invention is not limited thereto. For example, the ratio between thickness t1, thickness t2, and thickness t3 may be 1:1:1, for example, thicknesses t1, t2, and t3 are all approximately 200 μm. It is worth mentioning that the above description is merely illustrative and is not intended to limit the present invention. In practical applications, the materials, thicknesses, shapes, other parameters, or combinations thereof of the flexible substrate 100, the first rigid substrate 103, and the second rigid substrate 104 may be the same, similar, or different.
[0035] like Figure 4 As shown, following the above steps, a first opening 103O is formed in the first rigid substrate 103 to expose the first adhesive layer 101 or the flexible substrate 100. Furthermore, following the above steps, a second opening 104O is formed in the second rigid substrate 104 to expose the second adhesive layer 102 or the flexible substrate 100. In some embodiments, the first opening 103O and / or the second opening 104O can be formed by laser drilling, ultrasonic drilling, mechanical drilling, other suitable processes, or combinations thereof, but the present invention is not limited thereto. In some embodiments, the first opening 103O and the second opening 104O correspond to each other in the vertical direction. For example, the projection of the first opening 103O in the vertical direction at least partially overlaps the projection of the second opening 104O in the vertical direction to facilitate the subsequent formation of a through-hole (e.g., through the entire core stack 10) Figure 5 (Through hole 100H). In some embodiments, the first opening 103O and the second opening 104O can be formed simultaneously in the same process, but the present invention is not limited thereto. In some embodiments where the materials of the first rigid substrate 103 and the second rigid substrate 104 are different, the first opening 103O and the second opening 104O can be formed in different processes respectively.
[0036] like Figure 5As shown, following the above steps, corresponding to the first opening 103O and the second opening 104O, the flexible substrate 100, the first adhesive layer 101 (if any residue remains), and the second adhesive layer 102 (if any residue remains) are removed to form a through-hole 100H. In some embodiments, the through-hole 100H can be formed by laser drilling, ultrasonic drilling, mechanical drilling, other suitable processes, or combinations thereof, but the present invention is not limited thereto. In some embodiments, the first opening 103O, the through-hole 100H, and the second opening 104O can be collectively referred to as the through-hole structure TS, which penetrates the entire core stack 10.
[0037] like Figure 6 As shown, following the above steps, a conductive material is disposed in the through-hole structure TS to form a first vertical conductive structure CS1. Specifically, the first vertical conductive structure CS1 is used to form an electrical connection on the upper and lower sides of the core stack 10. For example, the conductive material may be aluminum (Al), copper (Cu), their alloys or compounds, but the present invention is not limited thereto. In some embodiments, a seed layer may be first disposed in the through-hole structure TS by physical vapor deposition (PVD), chemical vapor deposition (CVD), other suitable processes or combinations thereof, and then the conductive material may be filled into the through-hole structure TS by electroplating, chemical plating, other suitable processes or combinations thereof, but the present invention is not limited thereto.
[0038] In some embodiments, the first vertical conductive structure CS1 includes a first portion P1, a second portion P2, and a third portion P3. The first portion P1 is located in the flexible substrate 100 and has a first maximum aperture d1. The second portion P2 is located in the first rigid substrate 103 and has a second maximum aperture d2. The third portion P3 is located in the second rigid substrate 104 and has a third maximum aperture d3. The first maximum aperture d1 is slightly smaller than the second maximum aperture d2 and the third maximum aperture d3. Specifically, the aperture of the first vertical conductive structure CS1 gradually decreases from both sides towards the center, thus having a funnel-like shape. In some embodiments, the flexible substrate 100 may have a higher coefficient of thermal expansion, while the rigid substrate (e.g., the first rigid substrate 103, the second rigid substrate 104) has a lower coefficient of thermal expansion. Therefore, in order to maintain a generally vertical shape, the aperture of the first vertical conductive structure CS1 at the position corresponding to the rigid substrate can be larger, and the aperture of the first vertical conductive structure CS1 at the position corresponding to the flexible substrate can be smaller. In this way, when the temperature rises, the degree of expansion of the first vertical conductive structure CS1 at the position corresponding to the rigid substrate (e.g., the first rigid substrate 103, the second rigid substrate 104) can match the degree of expansion of the first vertical conductive structure CS1 at the position corresponding to the flexible substrate 100, without excessive deformation.
[0039] In some embodiments, the second portion P2 of the first vertical conductive structure CS1 further has a first minimum aperture d4, the third portion P3 further has a second minimum aperture d5, and the first maximum aperture d1 is smaller than the first minimum aperture d4 and the second minimum aperture d5 (for example, see reference). Figure 6 The first vertical conductive structure CS1 is located in the left half of the structure. In other words, the first vertical conductive structure CS1 has a step or stepped portion. For example, this can be achieved by increasing the size of the step. Figure 5 The dimensional difference between the first opening 103O and the through hole 100H may increase Figure 5 The dimensional difference between the second opening 104O and the through hole 100H creates the step or stepped portion described above. This further reduces the precision requirements for aperture control, thereby increasing process margin.
[0040] It is worth noting that the specific structures described above are merely examples and are not intended to limit the present invention. In some embodiments, when the coefficient of thermal expansion of the rigid substrate (e.g., the first rigid substrate 103 and / or the second rigid substrate 104) is similar to that of the flexible substrate 100, the first maximum aperture d1 can be made similar to the second maximum aperture d2 and the third maximum aperture d3, or the entire first vertical conductive structure CS1 can be made to have a nearly vertical shape. In this case, the first vertical conductive structure CS1 will not deform even at higher temperatures.
[0041] like Figure 7 As shown, following the above steps, a first circuit stack 11 is formed on the first rigid substrate 103. Specifically, the first circuit stack 11 includes a first dielectric layer 110 and a first circuit layer 111, and the first circuit layer 111 is disposed on or within the first dielectric layer 110. In some embodiments, the material of the first dielectric layer 110 may be or may include epoxy resin (exopy), polyimide (PI), build-up material (ABF), other suitable dielectric materials, or combinations thereof, but the present invention is not limited thereto. In some embodiments, the material of the first circuit layer 111 may be or may include aluminum (Al), copper (Cu), alloys thereof, or compounds thereof, but the present invention is not limited thereto.
[0042] In some embodiments, a first dielectric layer 110 can be formed on a first rigid substrate 103 by a build-up process, and a first circuit layer 111 can be formed in the first dielectric layer 110 by a combination of deposition, photolithography, and etching processes. In some embodiments, the deposition process 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, 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, or combinations thereof, but the present invention is not limited thereto.
[0043] In some embodiments, the first circuit stack 11 may further include a second vertical conductive structure CS2. The second vertical conductive structure CS2 is disposed in the first dielectric layer 110 and electrically connected to the first vertical conductive structure CS1 or the first circuit layer 111. The second vertical conductive structure CS2 may be formed by referring to the drilling process for forming openings (e.g., the first opening 103O or the second opening 104O) or vias (e.g., via 100H) mentioned above, and by referring to the process for forming the first vertical conductive structure CS1 mentioned above, which will not be repeated here.
[0044] like Figure 7 As shown, following the above steps, a second circuit stack 12 is formed on the second rigid substrate 104. Specifically, the second circuit stack 12 includes a second dielectric layer 120 and a second circuit layer 121, with the second circuit layer 121 disposed on or within the second dielectric layer 120. In some embodiments, the material of the second dielectric layer 120 may be or may include epoxy resin (exopy), polyimide (PI), build-up material (ABF), other suitable dielectric materials, or combinations thereof, but the present invention is not limited thereto. In some embodiments, the material of the second circuit layer 121 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 second dielectric layer 120 can be formed on the second rigid substrate 104 by a build-up process, and the second circuit layer 121 can be formed within the second dielectric layer 120 by a combination of deposition, photolithography, and etching processes.
[0045] In some embodiments, the second circuit stack 12 further includes a third vertical conductive structure CS3. The third vertical conductive structure CS3 is disposed in the second dielectric layer 120 and electrically connected to the first vertical conductive structure CS1 or the second circuit layer 121. The third vertical conductive structure CS3 can be formed by referring to the drilling process for forming openings (e.g., the first opening 103O or the second opening 104O) or vias (e.g., via 100H) mentioned above, and by referring to the process for forming the first vertical conductive structure CS1 mentioned above, which will not be repeated here.
[0046] In some embodiments, the materials, thicknesses, shapes, structures, other parameters, or combinations thereof of the first circuit stack 11 and the second circuit stack 12 may be the same, similar, or different. In some embodiments, the first circuit stack 11 and the second circuit stack 12 may be formed in the same or different process flows.
[0047] like Figure 7As shown, following the above steps, a first protective layer 13 is provided on the first circuit stack 11, and a second protective layer 14 is provided on the second circuit stack 12. Specifically, the first protective layer 13 is provided on the first dielectric layer 110 and exposes the second vertical conductive structure CS2 or the first circuit layer 111. On the other hand, the second protective layer 14 is provided on the second dielectric layer 120 and exposes the third vertical conductive structure CS3 or the second circuit layer 121. In some embodiments, the first protective layer 13 and / or the second protective layer 14 may be or may include solder mask ink, but the present invention is not limited thereto. In some embodiments, the first protective layer 13 and / or the second protective layer 14 may be provided by printing, spray coating, other suitable processes or combinations thereof, but the present invention is not limited thereto.
[0048] like Figure 8 As shown, following the steps described above, an electrical connector 15 is provided on the second vertical conductive structure CS2 or the first circuit layer 111 exposed from the first protective layer 13. Specifically, the electrical connector 15 is used to connect the circuit board structure to other electronic components. In some embodiments, the electrical connector 15 may be or may include a solder ball, but the present invention is not limited thereto.
[0049] like Figure 8 and Figure 9 As shown, following the above steps, a dicing process (DP) is performed to divide the entire circuit board into multiple independent circuit board structures 1. Each independent circuit board structure 1 includes a core stack 10, a first circuit stack 11, a second circuit stack 12, a first protective layer 13, a second protective layer 14, and electrical connectors 15. The core stack 10 includes a flexible substrate 100, a first adhesive layer 101, a second adhesive layer 102, a first rigid substrate 103, a second rigid substrate 104, and a first vertical conductive structure CS1. The first circuit stack 11 includes a first dielectric layer 110, a first circuit layer 111, and a second vertical conductive structure CS2. The second circuit stack 12 includes a second dielectric layer 120, a second circuit layer 121, and a third vertical conductive structure CS3. Compared with previous circuit board structures, the circuit board structure of this invention uses a core stack 10 with a composite material to avoid warping or deformation problems while maintaining high mechanical strength (or high modulus of elasticity).
[0050] Reference Figure 10This is a schematic diagram of a circuit board structure according to some embodiments of the present invention. As shown in the figure, in some embodiments, the first circuit stack 11 may further include a third rigid substrate 16, and the third rigid substrate 16 is disposed on or in the first dielectric layer 110. In other words, the present invention can also provide more rigid substrates as needed to enhance the mechanical strength (or modulus of elasticity) of the entire circuit board structure. Similarly, the second circuit stack 12 may also include a fourth rigid substrate 17, and the fourth rigid substrate 17 is disposed on or in the second dielectric layer 120.
[0051] In some embodiments, the third rigid substrate 16 and / or the fourth rigid substrate 17 may be or may include: a glass substrate, such as borosilicate glass (BSG), quartz glass, or alkali-free glass; a glass cloth epoxy resin board (FR4); other suitable materials or combinations thereof, but the present invention is not limited thereto. In some embodiments, the materials, thicknesses, shapes, other parameters, or combinations thereof of the first rigid substrate 103, the second rigid substrate 104, the third rigid substrate 16, and / or the fourth rigid substrate 17 may be the same, similar, or different to meet different design requirements.
[0052] In summary, this invention provides a circuit board structure that combines soft and hard materials into a core stack, which is then used as the main substrate. In this way, the circuit board structure of this invention maintains high strength while avoiding some of the problems that may arise when using only a hard substrate as the main substrate.
[0053] 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.
[0054] [Symbol Explanation]
[0055] 1: Circuit board structure
[0056] 10: Core Stack
[0057] 100: Flexible substrate
[0058] 100A: First surface
[0059] 100B: Second Surface
[0060] 100H: Through hole
[0061] 101: First adhesive layer
[0062] 102: Second adhesive layer
[0063] 103: First hard substrate
[0064] 103O: First opening
[0065] 104: Second rigid substrate
[0066] 104O: Second opening
[0067] 11: First circuit stack
[0068] 110: First dielectric layer
[0069] 111: First circuit layer
[0070] 12: Second circuit stack
[0071] 120: Second dielectric layer
[0072] 121: Second Circuit Layer
[0073] 13: First protective layer
[0074] 14: Second protective layer
[0075] 15: Electrical connectors
[0076] 16: Third rigid substrate
[0077] 17: Fourth hard substrate
[0078] CS1: First vertical conductive structure
[0079] CS2: Second vertical conductive structure
[0080] CS3: Third vertical conductive structure
[0081] d1: First maximum aperture
[0082] d2: Second largest aperture
[0083] d3: Third largest aperture
[0084] d4: First minimum aperture
[0085] d5: Second minimum aperture
[0086] DP: Cutting process
[0087] P1: Part 1
[0088] P2: Part Two
[0089] P3: Part Three
[0090] t1: Thickness
[0091] t2: thickness
[0092] t3: Thickness
[0093] TS: Through-hole structure.
Claims
1. A circuit board structure, characterized in that, include: The core stack includes: A flexible substrate having a first surface and a second surface that are opposite to each other; A first rigid substrate is disposed on the first surface; and A second rigid substrate is disposed on the second surface; A first circuit stack, disposed on one side of the core stack, includes: A first dielectric layer is disposed on the first rigid substrate; and The first circuit layer is disposed on or in the first dielectric layer.
2. The circuit board structure according to claim 1, characterized in that, The core stack also includes: A first adhesive layer is disposed between the first rigid substrate and the flexible substrate; and A second adhesive layer is disposed between the second rigid substrate and the flexible substrate.
3. The circuit board structure according to claim 1, characterized in that, The core stack also includes: A first vertical conductive structure is disposed in the flexible substrate, the first rigid substrate and the second rigid substrate.
4. The circuit board structure according to claim 3, characterized in that, The first vertical conductive structure includes: The first portion is located in the flexible substrate and has a first maximum aperture. The second portion is located within the first rigid substrate and has a second maximum aperture; and The third part is located in the second rigid substrate and has a third maximum aperture. The first maximum aperture is smaller than the second maximum aperture and the third maximum aperture.
5. The circuit board structure according to claim 4, characterized in that, The second part also has a first minimum aperture, the third part also has a second minimum aperture, and the first maximum aperture is smaller than the first minimum aperture and the second minimum aperture.
6. The circuit board structure according to claim 3, characterized in that, The first circuit stack also includes: The second vertical conductive structure is disposed in the first dielectric layer and electrically connected to the first vertical conductive structure or the first circuit layer.
7. The circuit board structure according to claim 1, characterized in that, The first circuit stack also includes: A third rigid substrate is disposed on or in the first dielectric layer.
8. The circuit board structure according to claim 3, characterized in that, Also includes: A second circuit stack, disposed on the other side of the core stack, includes: A second dielectric layer is disposed on the second rigid substrate; as well as The second circuit layer is disposed on the second dielectric layer.
9. The circuit board structure according to claim 8, characterized in that, The second circuit stack also includes: A third vertical conductive structure is disposed within the second dielectric layer and electrically connected to the first vertical conductive structure or the second circuit layer.
10. The circuit board structure according to claim 8, characterized in that, The second circuit stack also includes: A fourth rigid substrate is disposed on or in the second dielectric layer.