Patent ID: 12256488

DESCRIPTION OF THE EMBODIMENTS

In the drawings, in order to show the illustrations clearly, the thickness of layers, films, panels and regions are exaggerated. Throughout the specification, the same reference numerals denotes the same element. It should be understood that when it is described that an element on the layer, film, region or substrate is “on” another element or “connected to” another element, it can be either directly on another element or connected to another element; alternatively, an intervening element may be present. On the contrary, when it is described that an element is “directly on another element” or “directly connected to” another element, no intervening element is present there. Herein, the terms “connected to” or “coupled to” may refer to physical and/or electrical connection. Alternatively, the terms “electrically connected” or “coupled to” may refer to that there is another element existed between two elements.

It should be understood that although the terms “first”, “second”, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, and/or sections should not be constrained by limitations of these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a “first” element, component, region, layer or section discussed below could be termed a “second” element, component, region, layer or section without departing from the teachings herein.

FIG.1is a schematic cross-sectional view of a circuit board structure according to an embodiment of the present disclosure.FIG.2is a schematic diagram of an equivalent circuit of a signal transmitting structure according to an embodiment of the present disclosure.FIG.3is a schematic diagram of a partial equivalent circuit of a uniform transmitting section according to an embodiment of the present disclosure.FIG.4Ais a schematic top view of a circuit board structure according to an embodiment of the present disclosure.FIG.4Bis a schematic top view of a circuit board structure according to an embodiment of the present disclosure.FIG.4Cis a schematic top view of a circuit board structure according to an embodiment of the disclosure.FIG.1may be a schematic cross-sectional view taken along the section line A-A′ ofFIG.4A, the section line B-B′ ofFIG.4Bor the section line C-C′ ofFIG.4C.FIG.2may be a schematic diagram of an equivalent circuit of the signal transmitting structure inFIG.1. For clarity, only few elements including a first top wiring layer132a, a second top wiring layer134a, a second dielectric layer123, a first conductive via V1and second conductive vias V2are shown inFIGS.4A to4C, and other omitted elements are described with reference toFIG.1.

Referring toFIG.1andFIG.2, a circuit board structure10includes a substrate110, a loop-wrapping ground layer114c, an insulating structure116, a first build-up structure120, a top wiring layer130a, a bottom wiring layer130b, a first conductive via V1, and a plurality of second conductive vias V2. The substrate110has an opening OP1, a first surface110aand a second surface110bopposite to the first surface110a. The loop-wrapping ground layer114c(or called “return-surrounding ground layer” in some examples) is disposed on the inner sidewall of the opening OP1of the substrate110. The insulating structure116is disposed in the opening OP1of the substrate110. The first build-up structure120is disposed on the first surface110aof the substrate110. The top wiring layer130ais disposed on the first build-up structure120. The top wiring layer130aincludes a first top wiring layer132aand a second top wiring layer134a. The bottom wiring layer130bis disposed on the second surface110bof the substrate110. The bottom wiring layer130bincludes a first bottom wiring layer132band a second bottom wiring layer134b. The first conductive via V1penetrates through the first build-up structure120and the insulating structure116, and is electrically connected to the first top wiring layer132aand the first bottom wiring layer132b. The insulating structure116is located between the loop-wrapping ground layer114cand the first conductive via V1. The second conductive vias V2penetrate through the substrate110and the first build-up structure120and surround the first conductive via V1, and are electrically connected to the second top wiring layer134aand the second bottom wiring layer134b. The loop-wrapping ground layer114cis located between the first conductive via V1and the second conductive vias V2, and is electrically connected to the second conductive vias V2.

The first bottom wiring layer132b, the first conductive via V1, the first top wiring layer132a, the second bottom wiring layer134b, the loop-wrapping ground layer114c, a part of the second conductive vias V2, the second top wiring layer134a, the insulating structure116, and a part of the first build-up structure120located between the first conductive via V1and the second conductive vias V2define a signal transmitting structure ST1, which is suitable for transmitting high frequency and high speed signals. Herein, the term “high frequency” refers to a frequency greater than 1 GHz; and the term “high speed” refers to a data transmission speed greater than 100 Mbps. The equivalent circuit X1of the signal transmitting structure ST1at least includes a first equivalent circuit C1, a second equivalent circuit C2, a third equivalent circuit C3and a fourth equivalent circuit C4. The first equivalent circuit C1corresponds to the first bottom wiring layer132band the second bottom wiring layer134bcorresponding to the first bottom wiring layer132b, which may correspond to, for example, a part of a first transmitting section S11as shown inFIG.1. The second equivalent circuit C2corresponds to the loop-wrapping ground layer114c, the insulating structure116and a part of the first conductive via V1corresponding to the loop-wrapping ground layer114c, which may correspond to, for example, a part of a transmitting section S12as shown inFIG.1. The third equivalent circuit C3corresponds to a part of the first build-up structure120located between the first conductive via V1and the second conductive vias V2, and a part of the first conductive via V1and a part of the second conductive vias V2located in the first build-up structure120, which may correspond to, for example, a third transmitting section S13as shown inFIG.1. The fourth equivalent circuit C4corresponds to the first top wiring layer132aand the second top wiring layer134acorresponding to the first top wiring layer132a, which may correspond to, for example, a part of a fourth transmitting section S14as shown inFIG.1. In some embodiments, the signal transmitting structure ST1includes a signal transmitting via ST11composed of a first transmitting section S11, a second transmitting section S12, a third transmitting section S13and a fourth transmitting section S14.

The first equivalent circuit C1, the second equivalent circuit C2, the third equivalent circuit C3and the fourth equivalent circuit C4respectively correspond to different uniform transmitting sections. The first equivalent circuit C1, the second equivalent circuit C2, the third equivalent circuit C3, and the fourth equivalent circuit C4are connected in series by the principle of series connection of an ABCD transmission matrix (or called “an ABCD transmission matrix connection principle” in some examples). Herein, the term “uniform transmitting section” refers to a transmitting section under a fixed signal frequency, and the unit length parameter of the equivalent circuit of the transmitting section is constant. In detail, as shown inFIG.3, the equivalent circuit of the uniform transmitting section is composed of multiple RLGC circuit units U connected in series, and each RLGC circuit unit U represents the equivalent circuit of the signal of a unit-length transmitting section in a cross-section. Each RLGC circuit unit U in the equivalent circuit of the uniform transmitting section has the same resistance (R) per unit length, inductance (L) per unit length, conductance (G) per unit length and capacitance (C) per unit length; that is, the unit length parameters (including inductance per unit length, capacitance per unit length, resistance per unit length and conductance per unit length) of the equivalent circuit of the uniform transmitting section are constants.

The term “principle of series connection of an ABCD transmission matrix” refers to different equivalent circuits connected in series. The ABCD transmission matrix can be multiplied sequentially according to the order of series connection to represent the ABCD transmission matrix of the overall equivalent circuit. For example, as shown inFIG.2, the equivalent circuit X11of the signal transmitting via ST11is composed of a first equivalent circuit C1, a second equivalent circuit C2, a third equivalent circuit C3and a fourth equivalent circuit C4sequentially connected in series. That is to say, the ABCD transmission matrix of the equivalent circuit X11is equal to the product of the ABCD transmission matrix of the first equivalent circuit C1, the ABCD transmission matrix of the second equivalent circuit C2, the ABCD transmission matrix of the third equivalent circuit C3, and the ABCD transmission matrix of the circuit C4, as shown in the following equation (1).

[ABCD]X⁢11=[ABCD]C⁢1[ABCD]C⁢2[ABCD]C⁢3[ABCD]C⁢4(1)

The ABCD transmission matrix is composed of a resistance per unit length (R), a inductance per unit length (L), a conductance per unit length (G) and a capacitance per unit length (C) in the equivalent circuit. Equation (2) is an example of the expression of a transmission line.

[ABCD]=[cosh⁡(γ⁢l)Z0·sinh⁡(γ⁢l)sinh⁡(γ⁢l)/Z0cosh⁢(γ⁢l)],(2)where l is a length of a uniform transmitting section, Z0is a reference impedance, and γ is a propagation constant expressed by equation (3):
γ=√{square root over ((R(f)+j2πfL(f))(G(f)+j2πfC(f)))}  (3),where f is a frequency, and R(f), L(f), G(f) and C(f) are frequency-dependent functions of a resistance per unit length, an inductance per unit length, a conductance per unit length, and a capacitance per unit length, respectively.

The ABCD transmission matrix can be further converted into an S-parameter matrix (also known as a “scattering matrix”), so as to obtain the frequency-domain characteristics of the transmitting section. In other words, the frequency domain characteristics of the signal transmitting via ST11are related to the unit length parameters in the first equivalent circuit C1, the second equivalent circuit C2, the third equivalent circuit C3and the fourth equivalent circuit C4, and the signal transmitting via ST11meets the requirement of impedance matching by designing the structure of each transmitting section and adjusting the corresponding unit length parameters.

In some embodiments, the unit length parameter of the first equivalent circuit C1, the unit length parameter of the second equivalent circuit C2, the unit length parameter of the third equivalent circuit C3and the unit length parameter of the fourth equivalent circuit C4are different from each other. In other words, the electrical characteristics of the uniform transmitting sections corresponding to the first equivalent circuit C1, the second equivalent circuit C2, the third equivalent circuit C3and the fourth equivalent circuit C4are different, e.g., having different geometric shapes or including different dielectric or conductive materials. The signal transmitting via ST11can meet the requirement of impedance matching by designing the first equivalent circuit C1, the second equivalent circuit C2, the third equivalent circuit C3and the fourth equivalent circuit C4, and selecting the structures or materials of the corresponding uniform transmitting sections.

In some embodiments, the first bottom wiring layer132b, the first conductive via V1and the first top wiring layer132adefine a signal transmitting path L11. The second bottom wiring layer134b, the loop-wrapping ground layer114c, the second conductive vias V2and the second top wiring layer134adefine a ground path L12, and the ground path L12surrounds the signal transmitting path L11. In this way, the signal transmitting path L11is surrounded by the ground path L12in a closed manner. The high-frequency high-speed signals can be transmitted through the signal transmitting path L11, and the return signals are generated through the ground path L12, so as to form a good high-frequency high-speed loop.

In some embodiments, one end of the equivalent circuit X1of the signal transmitting structure ST1is connected to a receiver Rx or a transmitter Tx, and another end of the equivalent circuit X1of the signal transmitting structure ST1is connected to an antenna A.

In some embodiments, the substrate110may include a core layer111, an inner wiring layer112a, an inner wiring layer112b, an inner wiring layer112c, a dielectric layer113a, a dielectric layer113b, a wiring layer114a, a wiring layer114band a wiring layer114d. The core layer111has an opening OP3, the inner wiring layer112aand the inner wiring layer112bare disposed on opposite sides of the core layer111, and the inner wiring layer112ccovers the inner sidewall of the opening OP3, and is structurally and electrically connected to the inner wiring layer112aand inner layer wiring layer112b. The dielectric layer113acovers the inner wiring layer112aand is located between the inner wiring layer112aand the wiring layer114a. The dielectric layer113bcovers the inner wiring layer112band is located between the inner wiring layer112band the wiring layer114b. The dielectric layer113aand the dielectric layer113bfill the opening OP3and are connected to each other. The wiring layer114ais disposed on the dielectric layer113a, and the wiring layer114bis disposed on the dielectric layer113b. The substrate110has an opening OP1and an opening OP2. The opening OP1penetrates through the wiring layer114a, the dielectric layer113a, the inner wiring layer112a, the core layer111, the inner wiring layer112b, the dielectric layer113band the wiring layer114b. The loop-wrapping ground layer114ccovers the inner sidewall of the opening OP1, and is structurally and electrically connected to the wiring layer114a, the inner wiring layer112a, the inner wiring layer112band the wiring layer114b. In some embodiments, the loop-wrapping ground layer114csurrounds a part of the first conductive via V1. In some embodiments, the insulating structure116fills the opening OP1and is flushed with the wiring layer114aand the wiring layer114b. In some embodiments, the dielectric layer113a, the dielectric layer113b, and the insulating structure116use high-frequency and high-speed materials, and the dielectric constant of the insulating structure116is selected to meet the requirement of impedance matching. For example, the dielectric loss of the insulating structure116is greater than 0 and less than 0.1, and the lower the dielectric loss, the higher the quality of the transmitted signal. The opening OP2penetrates through the wiring layer114a, the dielectric layer113a, the inner wiring layer112a, the core layer111, the inner wiring layer112b, the dielectric layer113band the wiring layer114b. The wiring layer114dcovers the inner sidewall of the opening OP2, and is structurally and electrically connected to the wiring layer114a, the inner wiring layer112a, the inner wiring layer112band the wiring layer114b. In some embodiments, the loop-wrapping ground layer114cis electrically connected to the second conductive vias V2through the wiring layer114a. In some embodiments, the opening OP1is located between the opening OP2and the opening OP3.FIG.1only schematically shows the substrate110but is not intended to limit the present disclosure. The substrate110may have multiple wiring layers, dielectric layers and openings according to actual needs, and its wiring design may be adjusted according to requirements.

In some embodiments, the first build-up structure120includes a first dielectric layer121, a first wiring layer122, a second dielectric layer123and a second wiring layer124. The first dielectric layer121is disposed on the first surface110aof the substrate110. The first wiring layer122is disposed on the first dielectric layer121. The second dielectric layer123is disposed on the first wiring layer122. The second wiring layer124is disposed on the second dielectric layer123, wherein the top wiring layer130ais disposed on the second wiring layer124.FIG.1only schematically shows the first build-up structure120but is not intended to limit the present disclosure. The number of dielectric layers and wiring layers of the first build-up structure120can be adjusted according to actual needs.

In some embodiments, the third transmitting section S13includes the first dielectric layer121and the second dielectric layer123located between the first conductive via V1and the second conductive vias V2, and a part of the first conductive via V1and a part of the second conductive vias V2located in the first build-up structure120. The third transmitting section S13does not include the first wiring layer122. When the first dielectric layer121and the second dielectric layer123have the same material, the third transmitting section S13is regarded as a single uniform transmitting section, which can be equivalent to the third equivalent circuit C3inFIG.2. In other embodiments, when the material of the first dielectric layer121is different from the material of the second dielectric layer123, the third transmitting section S13can be regarded as two different uniform transmitting sections, which respectively correspond to equivalent circuits of transmitting sections with different unit length parameters. However, the present disclosure is not limited thereto.

In some embodiments, the first conductive via V1includes a through hole T1and a conductive layer130c, the through hole T1penetrates through the first build-up structure layer120and the insulating structure116, and the conductive layer130ccovers the inner sidewall of the through hole T1and is electrically connected to the first top wiring layer132aand the first bottom wiring layer132b. Each of the second conductive via V2includes a through hole T2and a conductive layer130d, the through hole T2penetrates through the first build-up structure layer120and the substrate110, and the conductive layer130dcovers the inner sidewall of the through hole T2and is electrically connected to the second top wiring layer134aand the second bottom wiring layer134b. In some embodiments, the through hole T1penetrates through the center of the insulating structure116; that is, the through hole T1and the insulating structure116may have the same axis, but the disclosure is not limited thereto. In other embodiments, the through hole T1may be deviated from the center of the insulating structure116.

In some embodiments, the circuit board structure10further includes a filling structure150disposed in the first conductive via V1and the second conductive vias V2. The material of the filling structure150may include resin (as a hole filler or a hole plugging agent), or a dielectric material with a dielectric constant higher than 3.6 and a dielectric loss lower than 0.05. In some embodiments, the filling structure150can fill the first conductive via V1and the second conductive vias V2, so that the top surface of the filling structure150is flushed with the top wiring layer130a, and the bottom surface of the filling structure150is flushed with the bottom wiring layer130b.

In some embodiments, the circuit board structure10further includes a first covering layer140aand a second covering layer140b. The first covering layer140ais disposed on the top wiring layer130aand the filling structure150, and the second covering layer140bis disposed on the bottom wiring layer130band the filling structure150.

In some embodiments, the equivalent circuit X1of the signal transmitting structure ST1further includes a fifth equivalent circuit C5connected between the fourth equivalent circuit C4and the antenna A. For example, the signal transmitting structure ST1further includes a signal transmitting line ST12connected to the signal transmitting via ST11. The ABCD transmission matrix of the equivalent circuit X1of the signal transmitting structure ST1is equal to the product of the ABCD transmission matrix of the equivalent circuit X11of the signal transmitting via ST11and the ABCD transmission matrix of the equivalent circuit X12of the signal transmitting line ST12, as shown in the following equation (4), wherein the equivalent circuit X12of the signal transmitting line ST12includes a fifth equivalent circuit C5; that is, the fifth equivalent circuit C5corresponds to the signal transmitting line ST12.

[ABCD]X⁢1=[ABCD]X⁢11[ABCD]X⁢12(4)

In some embodiments, as shown inFIG.4A, the first top wiring layer132aincludes a first top pad portion132a-1and a first top wiring portion132a-2. The first top pad portion132a-1is disposed at the end of the first conductive via V1and is electrically connected to the first conductive via V1. The first top wiring portion132a-2extends from the first top pad portion132a-1and is electrically connected to the first top pad portion132a-1.

In some embodiments, the fourth equivalent circuit C4may correspond to the first top pad portion132a-1, and the fifth equivalent circuit C5may correspond to the first top wiring portion132a-2. That is to say, the first top wiring part132a-2and a part of the second top wiring layer134asurrounding the first top wiring part132a-2can constitute a part of the signal transmitting line ST12; the first top pad portion132a-1and a part of the second top wiring layer134asurrounding the first top pad portion132a-1may constitute a part of the fourth transmitting section S14.

In some embodiments, the fifth equivalent circuit C5may correspond to a plurality of uniform transmitting sections, and the equivalent circuits of the uniform transmitting sections are connected in series according to an ABCD transmission matrix connection principle, so as to match an impedance. For example, in the embodiment ofFIG.4B, the first top wiring portion132a-2has a tapered line width near the first top pad portion132a-1, and different line widths may represent different uniform transmitting sections. With the tapered line width design of the first top wiring portion132a-2, the fifth equivalent circuit C5can have expected parameters of resistance, inductance, conductance and capacitance, thereby meeting the requirement of impedance matching. In the embodiment ofFIG.4C, the first top wiring portion132a-2may be formed by connecting a plurality of line segments a, b, and c with different line widths; that is, the ABCD transmission matrix of the equivalent circuit of the first top wiring part132a-2(i.e. the fifth equivalent circuit C5) is equal to the product of the ABCD transmission matrix of the equivalent circuits of the line segments a, b and c, as shown in the following equation (5).

[ABCD]C5=[ABCD]a[ABCD]b[ABCD]c(5)

In this way, the fifth equivalent circuit C5can have expected parameters of resistance, inductance, conductance and capacitance by designing the line widths and lengths of the multiple line segments a, b and c, thereby meeting the requirement of impedance matching.

Referring toFIG.1andFIG.4A, in some embodiments, the first top pad portion132a-1and its corresponding topmost wiring layer (i.e., the second wiring layer124) of the first build-up structure120and the first covering layer140amay constitute a first top pad p1. The second top wiring layer134aand its corresponding topmost wiring layer (i.e., the second wiring layer124) of the first build-up structure120and the first covering layer140amay constitute a top ground structure p2. The top ground structure p2surrounds the first top pad p1. In some embodiments, the fourth transmitting section S14includes the first top pad p1and a part of the top ground structure p2. When the top wiring layer130a, the second wiring layer124and the first covering layer140ahave the same material, such as copper, the fourth transmitting section S14is regarded as a single uniform transmitting section, which can be equivalent to the fourth equivalent circuit C4inFIG.2. In other embodiments, when the materials of the top wiring layer130a, the second wiring layer124, and the first covering layer140aare different, and the fourth transmitting section S4can be regarded as three different uniform transmitting sections, which respectively correspond to equivalent circuits of transmitting sections with different unit length parameters. However, the present disclosure is not limited thereto. Although the top ground structure p2is shown as a blanket structure inFIG.1, the present disclosure is not limited thereto. The top ground structure p2may also be patterned to form a plurality of top ground pads (not shown) surrounding the first top pad p1.

In some embodiments, the sidewalls of the first top wiring layer132aand the corresponding second wiring layer124and the first covering layer140aare flushed with each other. The sidewalls of the second top wiring layer134aand the corresponding second wiring layer124and the first covering layer140aare flushed with each other.

In some embodiments, the first bottom wiring layer132band the corresponding second covering layer140bmay constitute a first bottom pad p3. The second bottom wiring layer134band the corresponding second covering layer140bcan constitute a plurality of second bottom pads p4. The second bottom pads p4surround the first bottom pad p3. In some embodiments, the first transmitting section Si includes a first bottom pad p3and a plurality of second bottom pads p4. When bottom wiring layer130band the second covering layer140bhave the same material, such as copper, the first transmitting section S11is regarded as a single uniform transmitting section, which can be equivalent to the first equivalent circuit C1inFIG.2. In other embodiments, when the materials of the bottom wiring layer130band the second covering layer140bare different, the first transmitting section S11can be regarded as two different uniform transmitting sections, which respectively correspond to equivalent circuits of transmitting sections with different unit length parameters. However, the present disclosure is not limited thereto.

In some embodiments, the sidewalls of the first bottom wiring layer132band the corresponding second covering layer140bare flushed with each other. The sidewalls of the second bottom wiring layer134band the corresponding second covering layer140bare flushed with each other.

In some embodiments, the first bottom wiring layer132bmay have a pad portion and/or a wiring portion similar to those described in the first top wiring layer132a, and the disclosure is not limited thereto.

FIG.5is a schematic cross-sectional view of a circuit board structure according to another embodiment of the present disclosure. Herein, it is noted that the embodiment inFIG.5continue using reference numbers and a part of the description of the embodiment inFIG.1, wherein the same or similar reference numbers denote the same or similar elements, and the description of the same technical content is omitted. For the description of the omitted content, reference may be made to the foregoing embodiments, and details are not repeated herein. For the schematic top views of the embodiment ofFIG.5, reference may be made toFIGS.4A to4C.

Referring toFIG.5, the main difference between the circuit board structure20and the circuit board structure10lies in that, the first build-up structure220of the circuit board structure20includes a first dielectric layer221and a first wiring layer222. The first dielectric layer221is disposed on the first surface110aof the substrate110. The first wiring layer222is disposed on the first dielectric layer221, wherein the top wiring layer130ais disposed on the second wiring layer222.

A first bottom wiring layer132b, a first conductive via V1, a first top wiring layer132a, a second bottom wiring layer134b, a part of the second conductive vias V2, a loop-wrapping ground layer114c, a second top wiring layer134a, an insulating structure116, and a part of the first build-up structure220located between the first conductive via V1and the second conductive vias V2define a signal transmitting structure ST2.FIG.2shows the equivalent circuit of the signal transmitting structure ST2, wherein the first equivalent circuit C1corresponds to the first bottom wiring layer132band the second bottom wiring layer134bcorresponding to the first bottom wiring layer132b, which may correspond to, for example, a part of a first transmitting section S21as shown inFIG.5. The second equivalent circuit C2corresponds to the loop-wrapping ground layer114c, the insulating structure116, and a part of the first conductive via V1corresponding to the loop-wrapping ground layer114c, which may correspond to, for example, a part of a second transmitting section S22as shown inFIG.5. The third equivalent circuit C3corresponds to the first dielectric layer221located between the first conductive via V1and the second conductive vias V2, and a part of the first conductive via V1and a part of the second conductive vias V2located in the first build-up structure220, which may correspond to, for example, a third transmitting section S23as shown inFIG.5. The fourth equivalent circuit C4corresponds to the first top pad portion132a-1and the second top wiring layer134acorresponding to the first top pad portion132a-1, which may correspond to, for example, a part of a fourth transmitting sections S24as shown inFIG.5. The fifth equivalent circuit C5corresponds to the first top wiring portion132a-2and the second top wiring layer134acorresponding to the first top wiring portion132a-2, as shown inFIGS.4A to4C. In some embodiments, the signal transmitting structure ST2includes a signal transmitting via ST21and a signal transmitting line ST12(with reference toFIG.4AtoFIG.4C), and the signal transmitting line ST12is composed of a first transmitting section S21, a second transmitting section S22, a transmitting section S23and a fourth transmitting section S24.

The first bottom wiring layer132b, the first conductive via V1and the first top wiring layer132adefine a signal transmitting path L21. The second bottom wiring layer134b, the loop-wrapping ground layer114c, the second conductive vias V2and the second top wiring layer134adefine a ground path L22, and the ground path L22surrounds the signal transmitting path L21. In this way, the signal transmitting path L21is surrounded by the ground path L22in a closed manner. The high-frequency high-speed signals can be transmitted through the signal transmitting path L21, and the return signals are generated through the ground path L22, so as to form a good high-frequency high-speed loop.

FIG.6is a schematic cross-sectional view of a circuit board structure according to another embodiment of the present disclosure.FIG.7is a schematic diagram of an equivalent circuit of a signal transmitting structure according to another embodiment of the present disclosure.FIG.7may be a schematic diagram of an equivalent circuit of the signal transmitting structure ST3inFIG.6. Herein, it is noted that the embodiment inFIG.6continues using reference numbers and a part of the description of the embodiment inFIG.1, wherein the same or similar reference numbers denote the same or similar elements, and the description of the same technical content is omitted. For the description of the omitted content, reference may be made to the foregoing embodiments, and details are not repeated herein. For the schematic top views of the embodiment ofFIG.6, reference may be made toFIGS.4A to4C.

Referring toFIG.6, the main difference between the circuit board structure30and the circuit board structure10lies in that, the first wiring layer122of the circuit board structure30includes first inner pads122aand second inner pads122bbetween a first conductive via V1and second conductive vias V2. The first inner pads122aare electrically connected to the first conductive via V1, and the second inner pads122bare electrically connected to the second conductive vias V2. In other embodiments, the first wiring layer122located between the first conductive via V1and the second conductive vias V2may only include the first inner pads122aor the second inner pads122b, but the present disclosure is not limited thereto. The configuration of the first inner pads122aand the second inner pads122bcan be adjusted according to actual needs, so as to meet the requirement of impedance matching.

A first bottom wiring layer132b, a first conductive via V1, a first top wiring layer132a, a second bottom wiring layer134b, a part of the second conductive vias V2, a loop-wrapping ground layer114c, a second top wiring layer134a, an insulating structure116, and a part of the first build-up structure120located between the first conductive via V1and the second conductive vias V2define a signal transmitting structure ST3. The signal transmitting structure ST3includes a signal transmitting via ST31and a signal transmitting line ST12(with reference toFIG.4AtoFIG.4C). The signal transmitting via ST31is composed of a first transmitting section S11, a second transmitting section S12, a third transmitting section S33and a fourth transmitting section S14. The third transmitting section S33includes a plurality of uniform sub-transmitting sections S33a, S33band S33c. The uniform sub-transmitting section S33aincludes a first dielectric layer121located between the first conductive via V1and the second conductive vias V2, and a part of the first conductive via V1and a part of the second conductive vias V2located in the first dielectric layer121. The uniform sub-transmitting section S33bincludes the first inner pads122a, the second inner pads122b, and a part of the first dielectric layer121located between the first inner pads122aand the second inner pads122b. The uniform sub-transmitting section S33cincludes a second dielectric layer123located between the first conductive via V1and the second conductive vias V2, and a part of the first conductive via V1and a part of the second conductive vias V2located in the second dielectric layer123.

As shown inFIG.7, the equivalent circuit X3of the signal transmitting structure ST3can include a first equivalent circuit C1, a second equivalent circuit C2, a third equivalent circuit C3, a seventh equivalent circuit C7, a sixth equivalent circuits C6, a fourth equivalent circuit C4and a fifth equivalent circuit C5connected in sequence. The first equivalent circuit C1corresponds to the first bottom wiring layer132band the second bottom wiring layer134bcorresponding to the first bottom wiring layer132b, which may correspond to, for example, the first transmitting section S11as shown inFIG.6. The second equivalent circuit C2corresponds to the loop-wrapping ground layer114c, the insulating structure116, and a part of the first conductive via V1corresponding to the loop-wrapping ground layer114c, which may correspond to, for example, the second transmitting section S12as shown in shown inFIG.6. The third equivalent circuit C3corresponds to the first dielectric layer121located between the first conductive via V1and the second conductive vias V2, which may correspond to, for example, the uniform sub-transmitting section S33aof the third transmitting section S33as shown inFIG.6. The seventh equivalent circuit C7corresponds to the first wiring layer122located between the first conductive via V1and the second conductive vias V2, which may correspond to, for example, the uniform sub-transmitting section S33bof the third transmitting section S33as shown inFIG.6. The sixth equivalent circuit C6corresponds to the second dielectric layer123located between the first conductive via V1and the second conductive vias V2, which may correspond to, for example, the uniform sub-transmitting section S33cof the third transmitting section S33as shown inFIG.6. The fourth equivalent circuit C4corresponds to the first top pad portion132a-1and the second top wiring layer134acorresponding to the first top pad portion132a-1, which may correspond to, for example, the fourth transmitting section S14as shown inFIG.6. The fifth equivalent circuit C5corresponds to the first top wiring portion132a-2and the second top wiring layer134acorresponding to the first top wiring portion132a-2, as shown inFIGS.4A to4C. In some embodiments, the equivalent circuit X31of the signal transmitting via ST31is composed of a first equivalent circuit C1, a second equivalent circuit C2, a third equivalent circuit C3, a seventh equivalent circuit C7, and a sixth equivalent circuit C6and a fourth equivalent circuit C4connected in series according to the ABCD transmission matrix connection principle.

The first bottom wiring layer132b, the first conductive via V1, the first inner pads122aand the first top wiring layer132adefine a signal transmitting path L31. The second bottom wiring layer134b, the loop-wrapping ground layer114c, the second conductive vias V2, the second inner pads122band the second top wiring layer134adefine a ground path L32, and the ground path L32surrounds the signal transmitting path L31. In this way, the signal transmitting path L31is surrounded by the ground path L32in a closed manner. The high-frequency high-speed signals can be transmitted through the signal transmitting path L31, and return signals are generated through the ground path L32, so as to form a good high-frequency high-speed loop.

FIG.8is a schematic cross-sectional view of a circuit board structure according to another embodiment of the present disclosure. Herein, it is noted that the embodiment inFIG.8continue using some reference numbers and a part of the description of the embodiment inFIG.6, wherein the same or similar reference numbers denote the same or similar elements, and the description of the same technical content is omitted. For the description of the omitted content, reference may be made to the foregoing embodiments, and details are not repeated herein. For the schematic top views of the embodiment ofFIG.8, reference may be made toFIGS.4A to4C.

Please refer toFIG.8, the main difference between the circuit board structure40and the circuit board structure30lies in that: the first wiring layer122of the circuit board structure40includes second inner pads122bbetween a first conductive via V1and second conductive vias V2, but does not include first inner pads. A first bottom wiring layer132b, a first conductive via V1, a first top wiring layer132a, a second bottom wiring layer134b, a part of the second conductive vias V2, a loop-wrapping ground layer114c, a second top wiring layer134a, an insulating structure116, and a part of the first build-up structure120located between the first conductive via V1and the second conductive vias V2define a signal transmitting structure ST4. The signal transmitting structure ST4includes a signal transmitting via ST41and a signal transmitting line ST12(with reference toFIG.4AtoFIG.4C). The signal transmitting via ST41is composed of a first transmitting section S11, a second transmitting section S12, a third transmitting section S43and a fourth transmitting section S14. The third transmitting section S43includes a plurality of uniform sub-transmitting sections S33a, S43band S33c, wherein the uniform sub-transmitting section S43bincludes the second inner pads122b, the first conductive via V1corresponding to the second inner pads122b, and a part of the dielectric layer121located between the first conductive via V1and the second inner pads122b.

As shown inFIG.7, the equivalent circuit X4of the signal transmitting structure ST4can include a first equivalent circuit C1, a second equivalent circuit C2, a third equivalent circuit C3, a seventh equivalent circuit C7, a sixth equivalent circuits C6, a fourth equivalent circuit C4and a fifth equivalent circuit C5connected in sequence. The first equivalent circuit C1corresponds to the first bottom wiring layer132band the second bottom wiring layer134bcorresponding to the first bottom wiring layer132b, which may correspond to, for example, the first transmitting section S11as shown inFIG.8. The second equivalent circuit C2corresponds to the loop-wrapping ground layer114c, the insulating structure116and a part of the first conductive via V1corresponding to the loop-wrapping ground layer114c, which may correspond to, for example, the second transmitting section S12as shown inFIG.8. The third equivalent circuit C3corresponds to the first dielectric layer121located between the first conductive via V1and the second conductive vias V2, which may correspond to, for example, the uniform sub-transmitting section S33aof the third transmitting section S43as shown inFIG.8. The seventh equivalent circuit C7may correspond to the first wiring layer122located between the first conductive via V1and the second conductive vias V2, which may correspond to, for example, the uniform sub-transmitting section S43bof the third transmitting section S43as shown inFIG.7. The sixth equivalent circuit C6corresponds to the second dielectric layer123located between the first conductive via V1and the second conductive vias V2, which may correspond to, for example, the uniform sub-transmitting section S33cof the third transmitting section S43as shown inFIG.8. The fourth equivalent circuit C4corresponds to the first top pad portion132a-1and the second top wiring layer134acorresponding to the first top pad portion132a-1, which may correspond to, for example, the fourth transmitting section S14as shown inFIG.8. The fifth equivalent circuit C5corresponds to the first top wiring portion132a-2and the second top wiring layer134acorresponding to the first top wiring portion132a-2, as shown inFIGS.4A to4C.

The first bottom wiring layer132b, the first conductive via V1and the first top wiring layer132adefine a signal transmitting path L41. The second bottom wiring layer134b, the loop-wrapping ground layer114c, the second conductive vias V2, the second inner pads122band the second top wiring layer134adefine a ground path L42, and the ground path L42surrounds the signal transmitting path L41. In this way, the signal transmitting path L41is surrounded by the ground path L42in a closed manner. The high-frequency high-speed signals can be transmitted through the signal transmitting path L41, and the return signals are generated through the ground path L42, so as to form a good high-frequency high-speed loop.

FIG.9is a schematic cross-sectional view of a circuit board structure according to another embodiment of the present disclosure.FIG.10is a schematic diagram of an equivalent circuit of a signal transmitting structure according to another embodiment of the present disclosure.FIG.10may be a schematic diagram of an equivalent circuit of the signal transmitting structure ST5inFIG.9. Herein, it is noted that the embodiment inFIG.9continue using some reference numbers and a part of the description of the embodiment inFIG.1, wherein the same or similar reference numbers denote the same or similar elements, and the description of the same technical content is omitted. For the description of the omitted content, reference may be made to the foregoing embodiments, and details are not repeated herein. For the schematic top views of the embodiment ofFIG.9, reference may be made toFIGS.4A to4C.

Referring toFIG.9, the main difference between the circuit board structure50and the circuit board structure10lies in that, the circuit board structure50further includes a second build-up structure520disposed on the second surface110bof the substrate110, the first conductive via V1and second conductive vias V2further penetrate the second build-up structure520. For example, the second build-up structure520may include a third dielectric layer522and a third wiring layer524. The third dielectric layer522is disposed on the second surface110bof the substrate110, the third wiring layer524is disposed on the third dielectric layer522, and the bottom wiring layer130bis disposed on the third wiring layer524. In some embodiments, the loop-wrapping ground layer114cis electrically connected to the second conductive vias V2through the wiring layers114aand114b.FIG.9only schematically shows the second build-up structure520but is not intended to limit the present disclosure. The number of dielectric layers and wiring layers of the second build-up structure520can be adjusted according to actual needs.

A first bottom wiring layer132b, a first conductive via V1, a first top wiring layer132a, a second bottom wiring layer134b, a part of the second conductive vias V2, a loop-wrapping ground layer114c, a second top wiring layer134a, an insulating structure116, and a part of the first build-up structure120located between the first conductive via V1and the second conductive vias V2define a signal transmitting structure ST5.

As shown inFIG.10, the equivalent circuit X5of the signal transmitting structure ST5can include a first equivalent circuit C1, a sixth equivalent circuit C6, a second equivalent circuit C2, a third equivalent circuit C3, a fourth equivalent circuits C4and a fifth equivalent circuit C5connected in sequence. The first equivalent circuit C1corresponds to the first bottom wiring layer132band the second bottom wiring layer134bcorresponding to the first bottom wiring layer132b, which may correspond to, for example, the first transmitting section S51as shown inFIG.9. The sixth equivalent circuit C6corresponds to a part of the second build-up structure520(such as the third dielectric layer522) located between the first conductive via V1and the second conductive vias V1, and a part of the first conductive via V1and a part of the second conductive vias V2located in the e second build-up structure520, which may correspond to, for example, the fifth transmitting section S55as shown inFIG.9. The second equivalent circuit C2corresponds to the loop-wrapping ground layer114c, the insulating structure116, and a part of the first conductive via V1corresponding to the loop-wrapping ground layer114c, which may correspond to, for example, the second transmitting section S52as shown inFIG.9. The third equivalent circuit C3corresponds to the first dielectric layer121located between the first conductive via V1and the second conductive vias V2, which may correspond to, for example, the third transmitting section S53as shown inFIG.9. The fourth equivalent circuit C4corresponds to the first top pad portion132a-1and the second top wiring layer134acorresponding to the first top pad portion132a-1, which may correspond to, for example, the fourth transmitting section S54as shown inFIG.9. The fifth equivalent circuit C5corresponds to the first top wiring portion132a-2and the second top wiring layer134acorresponding to the first top wiring portion132a-2, as shown inFIGS.4A to4C. In some embodiments, the signal transmitting structure ST5includes a signal transmitting via ST51and a signal transmitting line ST12(with reference toFIG.4AtoFIG.4C). The signal transmitting via ST51is composed of a first transmitting section S51, a second transmitting section S52, a transmitting section S53, a fourth transmitting section S54and a fifth transmitting section S55. In some embodiments, the equivalent circuit X51of the signal transmitting via ST51is composed of a first equivalent circuit C1, a sixth equivalent circuit C6, a second equivalent circuit C2, a third equivalent circuit C3and a fourth equivalent circuit C4according to the ABCD transmission matrix connection principle.

In some embodiments, the first bottom wiring layer132band the corresponding second covering layer140band third wiring layer524may constitute a first bottom pad p3′. The second bottom wiring layer134band the corresponding second covering layer140band third wiring layer524may constitute a plurality of second bottom pads p4′. The second bottom pads p4′ surround the first bottom pad p3′. In some embodiments, the first transmitting section S51includes a first bottom pad p3′ and a plurality of second bottom pads p4′. When a bottom wiring layer130b, the third wiring layer524and the second covering layer140bhave the same material, such as copper, the first transmitting section S51is regarded as a single uniform transmitting section, which can be equivalent to the first equivalent circuit C1inFIG.10. In other embodiments, when the materials of the bottom wiring layer130b, the third wiring layer524, and the second covering layer140bare different, and the first transmitting section S51may be regarded as three different uniform transmitting sections, which respectively correspond to equivalent circuits of transmitting sections with different unit length parameters. However, the present disclosure is not limited thereto.

In some embodiments, the sidewalls of the first bottom wiring layer132band the corresponding third wiring layer524and the second covering layer140bare flushed with each other. The sidewalls of the second bottom wiring layer134band the corresponding third wiring layer524and the second covering layer140bare flushed with each other.

The first bottom wiring layer132b, the first conductive via V1and the first top wiring layer132adefine a signal transmitting path L51, the second bottom wiring layer134b, the second conductive vias V2, the wiring layer114b, the loop-wrapping ground layer114c, the wiring layer114aand the second top wiring layer134adefine a ground path L52, and the ground path L52surrounds the signal transmitting path L51. In this way, the signal transmitting path L51is surrounded by the ground path L52and is enclosed in a closed manner. The high-frequency high-speed signals can be transmitted through the signal transmitting path L51, and the return signals are generated through the ground path L52, so as to form a good high-frequency high-speed loop.

FIG.11is a schematic cross-sectional view of a circuit board structure according to another embodiment of the present disclosure.FIG.12is a schematic top view of a circuit board structure according to an embodiment of the present disclosure.FIG.13is a schematic diagram of an equivalent circuit of a signal transmitting structure according to another embodiment of the present disclosure. Herein, it is noted that the embodiments inFIGS.11and12continue using reference numbers and a part of the description of the embodiments inFIGS.1and4A, wherein the same or similar reference numbers denote the same or similar elements, and the description of the same technical content is omitted. For the description of the omitted content, reference may be made to the foregoing embodiments, and details are not repeated herein.FIG.11may be a schematic cross-sectional view along the line D-D′ inFIG.12.FIG.13may be a schematic diagram of an equivalent circuit of the signal transmitting structure ST6inFIG.11.

Referring toFIGS.11and12, the main difference between the circuit board structure60and the circuit board structure10lies in that, the circuit board structure60does not include a first top pad, so as to expose the surface of the filling structure150and a part of the conductive layer130c. That is to say, the first top wiring layer132aonly includes a first top wiring portion132a-2, and the first top wiring portion132a-2extends from the end of the first conductive via V1and is electrically connected to the first conductive via V1. That is to say, the first top wiring portion132a-2extends from the exposed part of the conductive layer130cand is electrically connected to the conductive layer130c.

A first bottom wiring layer132b, a first conductive via V1, a first top wiring layer132a, a second bottom wiring layer134b, a part of the second conductive vias V2, a loop-wrapping ground layer114c, a second top wiring layer134a, an insulating structure116, and a part of the first build-up structure120located between the first conductive via V1and the second conductive vias V2define a signal transmitting structure ST6. The signal transmitting structure ST6includes a signal transmitting via ST61and a signal transmitting line ST62. The signal transmitting via ST61is composed of a first transmitting section S11, a second transmitting section S12and a third transmitting section S13. The signal transmitting line ST62is constituted by the first top wiring portion132a-2. The equivalent circuit X6of the signal transmitting structure ST6includes a first equivalent circuit C1, a second equivalent circuit C2, a third equivalent circuit C3, and a fourth equivalent circuit C4connected in sequence. The first equivalent circuit C1corresponds to the first bottom wiring layer132band the second bottom wiring layer134bcorresponding to the first bottom wiring layer132b, which may correspond to, for example, a part of the first transmitting section S11as shown inFIG.11The second equivalent circuit C2corresponds to the loop-wrapping ground layer114c, the insulating structure116, and a part of the first conductive via V1corresponding to the loop-wrapping ground layer114c, which may correspond to, for example, a part of the second transmitting section S12as shown inFIG.11. The third equivalent circuit C3corresponds to a part of the first build-up structure120located between the first conductive via V1and the second conductive vias V2, and a part of the first conductive via V1and a part of the second conductive vias V2located in the first build-up structure120, which may correspond to, for example, the third transmitting section S13shown inFIG.11. The fourth equivalent circuit C4corresponds to the first top wiring portion132a-2and a part of the second top wiring layer134asurrounding the first top wiring portion132a-2, as shown inFIG.12. The equivalent circuit X61of the signal transmitting via ST61is composed of a first equivalent circuit C1, a second equivalent circuit C2and a third equivalent circuit C3connected in sequence according to the ABCD transmission matrix connection principle. The equivalent circuit X62of the signal transmitting line ST62includes a fourth equivalent circuit C4. In other embodiments, the first top wiring portion132a-2can be formed by connecting multiple line segments with different line widths (similar to the first top wiring portion132a-2inFIG.4C), so as to adjust resistance, inductance, conductance and capacitance parameters of the fourth equivalent circuit C4to meet the needs of impedance matching.

The first bottom wiring layer132b, the first conductive via V1and the first top wiring layer132adefine a signal transmitting path L61, the second bottom wiring layer134b, the loop-wrapping ground layer114c, the second conductive vias V2and the second top wiring layer134adefine a ground path L62, and the ground path L62surrounds the signal transmitting path L61. In this way, the signal transmitting path L61is surrounded by the ground path L62in a closed manner. The high-frequency high-speed signals can be transmitted through the signal transmitting path L61, and the return signals are generated through the ground path L62, so as to form a good high-frequency high-speed loop.

In summary, the circuit board structure of the present disclosure has a signal transmitting structure. The equivalent circuit of the signal transmitting structure at least includes a first equivalent circuit, a second equivalent circuit, a third equivalent circuit and a fourth equivalent circuit, which respectively correspond to different uniform transmitting sections, and the signal transmitting path of each uniform transmitting section is surrounded by the ground path and enclosed in a closed manner. Such configuration can reduce energy loss and noise interference, thereby forming a good high-frequency and high-speed signal transmitting loop, and improving signal integrity and reliability.

Although the present disclosure has been disclosed above with the embodiments, it is not intended to limit the present disclosure. Anyone with ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present disclosure. The scope of protection of the present disclosure should be defined by the scope of the appended patent application.