Circuit board and manufacturing method thereof

Abstract

The present invention provides a circuit board and a manufacturing method thereof. Between two power planes, they are connected by at least one trench structure, and the trench structure is completely filled with a conductive metal, and the conductive metal electrically connects the two power planes; the current-carrying capacity of the conductive metal in the current direction substantially perpendicular to the power plane is greater than or equal to the current-carrying capacity of the power plane in the current direction parallel to the power plane. A conductive metal with excellent conductivity is formed in a trench with a trapezoidal longitudinal cross-sectional shape by electroplating a metal or embedding a metal block or a metal sheet, greatly increasing the current-carrying area of the current, increasing the current-carrying capacity of each layer of current lines, so that unnecessary power line routing can be reduced and more signal line routing space can be provided.

Description

Technical Field

[0001] The present invention relates to the field of circuit boards, and particularly to a circuit board and a manufacturing method thereof. Background Art

[0002] With the development of electronic devices, there are more and more surface-mounted devices on the circuit board, and the circuit traces are correspondingly more and more complex.

[0003] When the surface-mounted devices on the circuit board are dense and the traces are complex, the power supply plane cannot be directly connected, and it is necessary to route through other layers to bypass the devices or other traces. In high-speed optical modules, the DSP current is often 10 - 20 A, and the current carried by the power plane is very large. As Figure 1 shown, the first power plane 11 on the L1 layer of the circuit board surface is separated into two regions 11a' and 11b' by other components 12', and the power plane routes through the second power plane 31' on the L3 layer. The two power planes (the first power plane 11' and the second power plane 31') are conductively connected by conductive vias 21'. The current-carrying capacity is limited, and a large number of conductive vias 21' occupy a large space and squeeze the routing space of other signal lines. Summary of the Invention

[0004] The purpose of the present invention is to provide a circuit board and a manufacturing method thereof.

[0005] The present invention provides a circuit board, which includes at least two conductive layers and an insulating layer provided between the at least two conductive layers. A first power plane and a second power plane are respectively provided in the two conductive layers. The first power plane and the second power plane are connected by at least one trench structure, and the trench structure is filled with a conductive metal, and the conductive metal electrically connects the first power plane and the second power plane; the current-carrying capacity of the conductive metal in the current direction substantially perpendicular to the first power plane and the second power plane is greater than or equal to the current-carrying capacity of the first power plane in the current direction parallel to the first power plane.

[0006] As a further improvement of the present invention, the cross-sectional area of the trench structure parallel to the circuit board surface is larger than the cross-sectional area of a common conductive via; the cross-section of the trench structure parallel to the circuit board surface has dimensions in at least two dimensions, and at least one of the dimensions in the at least two dimensions is larger than the depth of the trench structure.

[0007] As a further improvement of the present invention, the trench structure is a laser grooving or a mechanically controlled deep milling groove.

[0008] As a further improvement of the present invention, the trench structure is a single trench, or the trench structure is a trench group formed by stacking a plurality of trenches.

[0009] As a further improvement of the present invention, the longitudinal cross-sectional shape of the groove is an inverted trapezoid.

[0010] As a further improvement of the present invention, the two conductive layers are respectively a first conductive layer and a third conductive layer, and a second conductive layer is further provided between the first conductive layer and the third conductive layer; a first insulating layer is provided between the first conductive layer and the second conductive layer, and a second insulating layer is provided between the second conductive layer and the third conductive layer; the second conductive layer is provided with signal lines.

[0011] As a further improvement of the present invention, it is characterized in that

[0012] The groove structure includes a first groove and a second groove that respectively penetrate the first insulating layer and the second insulating layer. The second conductive layer is further provided with connection pads, and the connection pads are insulated from the signal lines; the connection pads are respectively electrically connected to the conductive metal in the first groove and the conductive metal in the second groove; or,

[0013] A single groove of the groove structure simultaneously penetrates the first insulating layer and the second insulating layer.

[0014] As a further improvement of the present invention, the conductive metal is copper filled in the groove.

[0015] The present invention also provides a method for manufacturing a circuit board, including the steps of:

[0016] Manufacturing a laminate including at least two power planes;

[0017] Forming at least one groove structure between the two power planes, and connecting the two power planes through the groove structure;

[0018] Forming a conductive metal in the groove structure, filling the groove structure with the conductive metal, and electrically connecting the two power planes through the conductive metal.

[0019] As a further improvement of the present invention, the groove structure is a single groove, or a groove group formed by stacking multiple grooves.

[0020] As a further improvement of the present invention, the manufacturing method of the groove structure includes:

[0021] Forming a single groove with a trapezoidal longitudinal cross-sectional shape or a groove group formed by stacking multiple grooves with trapezoidal longitudinal cross-sectional shapes by means of laser grooving or mechanical controlled-depth milling.

[0022] As a further improvement of the present invention, the manufacturing of the laminate including at least two power planes and the manufacturing method of forming the groove structure specifically include the following steps:

[0023] Provide a second insulating layer with a second conductive layer and a third conductive layer respectively covered on the upper and lower surfaces;

[0024] Form at least one second trench penetrating the second insulating layer, form the conductive metal in the second trench, and electrically connect the second conductive layer and the third conductive layer;

[0025] Etch a second conductive pattern on the second conductive layer, and etch a third conductive pattern on the third conductive layer; the second conductive pattern includes a connection pad covering the second trench, and the third conductive pattern includes a second power plane electrically connected to the second trench;

[0026] Laminating a first insulating layer and a first conductive layer on one side of the second conductive layer;

[0027] Form two first trenches stacked on the second trench in the first insulating layer, form the conductive metal in the first trench, and electrically connect the first conductive layer and the connection pad;

[0028] Etch a first conductive pattern on the first conductive layer, and the first conductive pattern includes a first power plane electrically connected to the conductive metal in the two first trenches.

[0029] As a further improvement of the present invention, the manufacturing of the laminate including at least two layers of power planes, and the manufacturing method for forming the trench structure specifically includes the following steps:

[0030] Provide a second insulating layer with a second conductive layer and a third conductive layer respectively covered on the upper and lower surfaces, etch a second conductive pattern on the second conductive layer, and etch a third conductive pattern on the third conductive layer. The second conductive pattern includes a blank area reserved for forming a trench, and the third conductive pattern includes a second power plane;

[0031] Laminating a first insulating layer and a first conductive layer on one side of the second conductive layer;

[0032] Form at least one trench penetrating the first insulating layer and the second insulating layer at the blank area, form the conductive metal in the trench, and the conductive metal electrically connects the second power plane and the first conductive layer;

[0033] Etch a first conductive pattern on the first conductive layer, and the first conductive pattern includes a first power plane electrically connected to the conductive metal.

[0034] As a further improvement of the present invention, "forming the conductive metal" specifically includes the steps:

[0035] Deposit a filling metal material in the trench to form the conductive metal.

[0036] As a further improvement of the present invention, "forming the conductive metal" specifically includes the steps of:

[0037] Embed a metal block or a metal sheet in the trench to form the conductive metal.

[0038] The beneficial effects of the present invention are as follows: By electroplating a metal or embedding a metal block or a metal sheet in a trench with a trapezoidal cross-sectional shape, the present invention forms a conductive metal with excellent conductivity, greatly increasing the current-carrying area of the current and enhancing the current-carrying capacity of each layer of current lines. As a result, unnecessary power line routing can be reduced, and more signal line routing space can be provided. Description of the Drawings

[0039] Figure 1 is a simplified three-dimensional schematic diagram of electrically connecting power planes between layers through conductive vias in the prior art (other components except power planes, vias, and a few components are omitted).

[0040] Figure 2 is a schematic diagram of the circuit board in Embodiment 1 of the present invention.

[0041] Figure 3 is a simplified three-dimensional schematic diagram of the circuit board in Embodiment 1 of the present invention (other components except power planes, trenches, and a few components are omitted, and the trench structure is a simple illustration).

[0042] Figure 4 is a schematic diagram of the circuit board in Embodiment 2 of the present invention.

[0043] Figure 5 is a schematic flow chart of the manufacturing method of the circuit board in Embodiment 4 of the present invention.

[0044] Figures 6 to 11 is a schematic diagram of each step of the manufacturing method of the circuit board in Embodiment 4 of the present invention.

[0045] Figure 12 is a schematic flow chart of the manufacturing method of the circuit board in Embodiment 5 of the present invention.

[0046] Figures 13 to 16 is a schematic diagram of each step of the manufacturing method of the circuit board in Embodiment 5 of the present invention. Detailed Description of the Invention

[0047] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.

[0048] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0049] For convenience of description, terms representing relative spatial positions are used in this article, such as "upper", "lower", "rear", "front", etc., to describe the relationship between one unit or feature shown in the drawings and another unit or feature. The terms of relative spatial positions may include different orientations of the device in use or operation other than the orientations shown in the drawings. For example, if the device in the drawing is flipped, the unit described as being "below" or "above" other units or features will be located "below" or "above" other units or features. Therefore, the exemplary term "below" can encompass both the lower and upper spatial orientations.

[0050] As Figure 2 and Figure 3 shown, the present invention provides a circuit board. The circuit board includes at least two conductive layers 1 and a screen insulation layer 2 provided between the two conductive layers 1. A first power plane 11a and a second power plane 11b are respectively provided in the two conductive layers 1. The circuit board further includes signal lines 13 located in different conductive layers, and vias (not shown) for electrically connecting the signal lines in different conductive layers.

[0051] The conductive layer 1 may also be provided with signal lines, ground lines, and various components 5, etc., without specific limitations.

[0052] The vias adopt common conductive vias, usually blind vias, buried vias, through vias, etc. in the shape of a cylinder or a truncated cone. They are located between the layers of the circuit board such as signal lines, and electrically connect the layers through the metal layer plated on their inner walls. Optionally, fillers such as epoxy resin are filled inside. According to the thickness difference of the circuit board, its inner diameter is usually about 8 - 24 mil.

[0053] The circuit board in the present invention also includes structures such as surface layer pads and ground layers in a conventional circuit board, which are similar to the prior art and will not be described in detail here.

[0054] In this embodiment, taking two power planes 11 as an example, in other embodiments, the number of power planes 11 can also be designed as other numbers according to actual needs. All power planes 11 or some of them are electrically connected through the trench 3 and the conductive metal 4 therein.

[0055] The two power planes 11 are connected through a trench structure, and the trench structure is filled with a conductive metal 4, and the conductive metal 4 electrically connects the two power planes 11.

[0056] The trench structure is a single trench 3, or the trench structure is a trench group formed by stacking a plurality of trenches 3.

[0057] In the present invention, the power planes are electrically connected through the conductive metal in the trench, and other components such as signal lines still use vias for electrical connection.

[0058] Further, the cross-sectional area of the trench 3 is larger than that of the via 3, and the conductive metal in the trench 3 has a current-carrying capacity at least equivalent to that of the power plane in the current direction substantially perpendicular to the power plane. The cross-section of the trench structure parallel to the circuit board surface has dimensions in at least two dimensions, and at least one of the dimensions in the at least two dimensions is larger than the depth of the trench structure. The trench structure can be a laser grooving or a mechanical controlled-depth milling groove.

[0059] The conductive metal 4 is a metal with excellent conductivity such as copper, which is formed by electroplating metal in the trench 3 or by burying a metal block or metal sheet matching the shape of the trench 3 into the trench 3.

[0060] Since the trench 3 is completely filled with the conductive metal 4 and its cross-sectional area is larger than that of the via 3, compared with the via 3, the current-carrying area is greatly increased. The conductive metal has a current-carrying capacity at least equivalent to that of the power plane in the current direction substantially perpendicular to the power plane, ensuring the current-carrying capacity between the power planes of each layer. Compared with ensuring the current-carrying capacity between the power planes located in different conductive layers by a large number of vias for electrical connection, under the same current-carrying capacity, the space occupied by the trench and the conductive metal therein is smaller than the space occupied by a plurality of dense vias, and more signal line routing space can be provided for the circuit board. And when the conductive metal 4 is formed by burying a metal block or metal sheet, problems such as holes that may exist due to electroplated conductive metal 4 can be avoided, thereby improving the conductivity.

[0061] Further, the longitudinal cross-sectional shape of the trench 3 is an inverted trapezoid.

[0062] The inverted trapezoid mentioned here refers to that in the manufacturing process, when forming the groove 3 by mechanical or laser means, the end closer to the grooving device is the lower trapezoidal surface with a longer length, and the end farther from the grooving device is the upper trapezoidal surface with a shorter length.

[0063] The longitudinal cross-sectional shape of the groove 3 is set as an inverted trapezoid. When the conductive metal 4 is formed by electroplating, the metal layer grows adhering to the side wall surface of the groove 3. Since the side wall surface of the groove 3 slopes upward and outward from bottom to top, the bottom space is relatively smaller. The metal layer grows along the obliquely upward direction, and the plated metal first fills the bottom space and then continues to fill the upper space, thereby forming a conductive metal 4 with better quality and reducing the hole problems that are likely to occur when plating metal over a large area in the groove or hole. Moreover, when the conductive metal 4 is formed by embedding a metal block or a metal sheet, the inclined side wall surface can increase the contact area between the metal block or metal sheet and the groove 3, thereby improving the bonding force between the two and enhancing the reliability of the circuit board.

[0064] The cross-sectional shape of the groove 3 can be adjusted according to the shape of the power plane 11, as long as it does not exceed the power plane. In addition, the distribution position and quantity of the grooves 3 can also be adjusted according to the size of the circuit board, the number and distribution positions of the signal lines.

[0065] In the present invention, there are various implementation manners for the groove 3 and the conductive metal 4. Several embodiments will be specifically described below.

[0066] As Figure 2 shown, in Embodiment 1, the circuit board includes three conductive layers stacked in sequence, namely the first conductive layer 1a, the second conductive layer 1b, and the third conductive layer 1c. A first insulating layer 2a is provided between the first conductive layer 1a and the second conductive layer 1b, and a second insulating layer 2b is provided between the second conductive layer 1b and the third conductive layer. Among them, the second conductive layer 1b is located between the first conductive layer 1a and the third conductive layer 1c. The first power plane 11a and the second power plane 11b are respectively provided on the first conductive layer 1a and the third conductive layer 1c. Signal lines 13 can be provided on the first conductive layer 1a, the second conductive layer 1b, and the third conductive layer 1c. The same signal line 13 located between different conductive layers is electrically connected through a conductive via.

[0067] The insulating layer 2 is a common insulating layer 2 material in existing circuit boards, such as an epoxy glass cloth substrate, or a woven fabric of aromatic polyamide resin fibers, or an epoxy non-woven fabric substrate, etc., which will not be elaborated here.

[0068] The trench group includes a first trench 3a and a second trench 3b that respectively penetrate through the first insulating layer 2a and the second insulating layer 2b. The second conductive layer 1b is further provided with a connection pad 12, and the signal line 13 and the connection pad 12 are insulated from each other. The conductive metal 4 in the first trench 3a is electrically connected to the connection pad 12 and the first power plane 11a, and the conductive metal 4 in the second trench 3b is electrically connected to the connection pad 12 and the second power plane 11b. A series electrical connection sequence of the first power plane 11a, the conductive metal 4 in the first trench 3a, the connection pad 12, the conductive metal 4 in the second trench 3b, and the second power plane 11b is formed in sequence. In this embodiment, the first power plane 11a is separated into two regions by other components or signal lines, and the two regions of the first power plane 11a are respectively electrically connected to both ends of the second power plane 11b through the above trench group, forming a current path from a partial region of the first power plane 11a, through the trench group, to the second power plane 11b, and then through the trench group to another partial region of the first power plane 11a.

[0069] In the segmented series trench structure in Embodiment 1, during the manufacturing process, a single trench 3 can be formed in each circuit layer and then laminated, thereby improving the manufacturing precision of the trench 3 and the conductive metal 4 inside it, enhancing the reliability of the circuit board and ensuring the manufacturing yield.

[0070] In some other embodiments of Embodiment 1, the number of circuit layers can also be adjusted according to actual needs, and the number of segmented trenches 3 can be adjusted according to different numbers of circuit layers, as long as a continuous series structure is formed.

[0071] Exemplarily, a group of trenches 3 are respectively provided on both sides of the signal line. In other embodiments of the present invention, the number of groups of trench 3 can also be adjusted according to the size of the circuit board, the scale and distribution position of the power lines, so as to make the current more uniform.

[0072] As Figure 4 shown, in Embodiment 2, the difference from Embodiment 1 is that:

[0073] The trench 3 simultaneously penetrates through the first insulating layer 2a and the second insulating layer 2b, and the conductive metal 4 on the inner wall of the trench 3 directly electrically connects the first power plane 11a and the second power plane 11b.

[0074] In the integrated trench 3 structure in Embodiment 2, during the manufacturing process, after laminating each layer, it can be formed by a single grooving process, which simplifies the process steps.

[0075] In Embodiment 1 and Embodiment 2, the two power planes are respectively disposed on the first conductive layer 1a and the third conductive layer 1c. In other embodiments, the two power planes can also be respectively disposed on adjacent two conductive layers, or other conductive layers, which can be designed according to the circuit board routing.

[0076] The present invention also provides a method for manufacturing a circuit board, comprising the steps of:

[0077] Fabricating a laminate including at least two power planes 11.

[0078] Forming at least one trench structure between the two power planes 11 to connect the two power planes 11 through the trench.

[0079] Furthermore, forming the trench structure includes forming a single trench 3, or forming a trench group formed by stacking multiple trenches 3.

[0080] Specifically, the trench 3 with a trapezoidal longitudinal cross-section is formed by laser grooving or mechanical controlled-depth milling.

[0081] Forming a conductive metal 4 in the trench 3, filling the trench 3 with the conductive metal 4, and electrically connecting the conductive metal 4 to the two power planes 11 respectively.

[0082] Fabricating vias 3 and etching the outer layer circuit.

[0083] Specifically, in the present invention, according to different trenches 3 and conductive metals 4, there are multiple manufacturing processes, which will be described in the following with multiple embodiments:

[0084] As Figure 5 shown, in Embodiment 3, forming a trench group includes the steps of:

[0085] S1a: As Figure 6 shown, providing a second insulating layer 2b with a second conductive layer 1b and a third conductive layer 1c respectively coated on the upper and lower surfaces.

[0086] S2a: As Figure 7 shown, forming at least one second trench 3b penetrating through the second insulating layer 2b, forming a conductive metal 4 in the second trench 3b, and electrically connecting the second conductive layer and the third conductive layer.

[0087] Specifically, the trench 3 is formed by continuous laser. According to the surface irradiated by the laser, the conductive layer on the surface of the second insulating layer 2b and the second insulating layer 2b are grooved by adjusting parameters such as the power and exposure time of the laser to form a trench 3 with an inverted trapezoidal longitudinal cross-section, while avoiding ablation of the conductive layer on the back surface of the second insulating layer 2b.

[0088] In some other embodiments of this embodiment, the trench 3 can also be formed by mechanical processing, such as controlled-depth milling.

[0089] Furthermore, in Embodiment 3, forming the conductive metal 4 specifically includes the steps of:

[0090] A conductive metal is formed by plating a filling metal material on the sidewalls of the trench 3 and the conductive layer exposed by the trench 3. Moreover, the conductive layer within the laser grooving region is supplemented with plating to electrically connect the conductive metal 4 to the conductive layer.

[0091] S3a: As Figure 8 shown, a second conductive pattern is etched on the second conductive layer 1b, and a third conductive pattern is etched on the third conductive layer 1c. The second conductive pattern 4 includes a connection pad 12 covering the second trench 3b, and the third conductive pattern includes a second power plane 11b connected to the second trench 3b.

[0092] S4a: As Figure 9 shown, a first insulating layer 2a and a first conductive layer 1a are laminated on one side of the second conductive layer 1b.

[0093] S5a: As Figure 10 shown, two first trenches 3a stacked on the second trench 3b are formed within the first insulating layer, a conductive metal 4 is formed within the first trenches 3a, and the first conductive layer 1a and the connection pad 12 are electrically connected.

[0094] Specifically, the step of forming the conductive metal 4 within the first trench 3a is similar to that in step S2a and will not be elaborated here.

[0095] S6a: As Figure 11 shown, a first conductive pattern is etched on the first conductive layer 1a. The first conductive pattern includes a first power plane 11a, and the two separated parts of the first power plane 11a are respectively electrically connected to the second power plane 11b through the conductive metal 4 within the first trench 3a.

[0096] The first conductive pattern may further include signal lines, etc., without specific limitation.

[0097] This manufacturing method may further include fabricating vias and etching outer layer circuits in other traces.

[0098] Steps such as via 3 fabrication, circuit etching, circuit layer comprehensive blackening, and lamination in the present invention are conventional technical means in the art and will not be elaborated here.

[0099] As Figure 12 shown, in Embodiment 4, a single trench 3 structure is formed, which includes the steps:

[0100] S1b: As Figure 13As shown, a second insulating layer 2b with a second conductive layer 1b and a third conductive layer 1c covering the upper and lower surfaces respectively is provided. A second conductive pattern is etched on the second conductive layer 1b, and a third conductive pattern is etched on the third conductive layer 1c. The second conductive pattern includes signal lines 13 and blank areas reserved for forming trenches (partial areas where the conductive layer is removed), and the third conductive pattern includes a second power plane 11b.

[0101] S2b: As Figure 14 shown, a first insulating layer 2a and a first conductive layer 1a are laminated on one side of the second conductive layer 1b.

[0102] S3b: As Figure 15 shown, at least one trench 3 penetrating the first insulating layer 2a and the second insulating layer 2b is formed. The trench 3 penetrates the blank area reserved in the second conductive pattern and is insulated from the signal lines. A conductive metal 4 is formed in the trench 3, and the conductive metal 4 is electrically connected to the second power plane 11b and the first conductive layer.

[0103] Specifically, the steps of forming the conductive metal 4 in the trench 3 are similar to steps S2a11 to S2a13 and will not be elaborated here.

[0104] S4b: As Figure 16 shown, a first conductive pattern is etched on the first conductive layer. The first conductive pattern includes a first power plane electrically connected to the conductive metal 4. In this embodiment, the first power plane 11a includes two separated parts, and the two separated parts of the first power plane 11a are respectively electrically connected to the second power plane 11b through the conductive metal 4 in the first trench 3a.

[0105] This manufacturing method may further include making vias in other traces and etching outer layer circuits.

[0106] In Embodiment 5, the difference from Embodiment 4 lies in the manufacturing process of the conductive metal 4, which includes the steps:

[0107] S2a1: Brown the metal block or metal sheet matching the shape of the trench 3.

[0108] Specifically, in this embodiment, the metal block or metal sheet is a copper block or copper sheet. Through browning treatment, the surfaces of the copper block and copper sheet become rougher, thereby increasing the bonding force between the copper block and the trench 3.

[0109] S2a2: Bury the metal block or metal sheet in the trench 3 to form the conductive metal.

[0110] Fix the metal block or metal sheet to the trench 3 by means of pressing.

[0111] In summary, in the present invention, a conductive metal with excellent electrical conductivity is formed by electroplating a metal or embedding a metal block or metal sheet in a groove having a trapezoidal cross-sectional shape, greatly increasing the overcurrent area of the current, increasing the current-carrying capacity of the conductive structure between each layer of power planes, reducing the occupied space, and providing more wiring space for the routing of signal lines.

[0112] It should be understood that although this specification is described according to embodiments, not every embodiment only includes an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0113] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A circuit board, the circuit board comprising at least two conductive layers and an insulating layer disposed between the at least two conductive layers, a first power plane and a second power plane being respectively disposed in the two conductive layers, characterized in that, The first power plane and the second power plane are connected by at least one trench structure filled with a conductive metal, and the conductive metal electrically connects the first power plane and the second power plane; Wherein, the cross-sectional area of the trench structure parallel to the surface of the circuit board is larger than the cross-sectional area of a common conductive via, so that the current-carrying capacity of the conductive metal in the current direction substantially perpendicular to the first power plane and the second power plane is greater than or equal to the current-carrying capacity of the first power plane in the current direction parallel to the first power plane; the cross-section of the trench structure parallel to the surface of the circuit board has dimensions in at least two dimensions, and at least one of the dimensions in the at least two dimensions is larger than the depth of the trench structure.

2. The circuit board according to claim 1, characterized in that: The trench structure is a laser grooving or a mechanically controlled depth milling groove.

3. The circuit board according to claim 1, characterized in that, The trench structure is a single trench, or the trench structure is a trench group formed by stacking a plurality of trenches.

4. The circuit board according to claim 3, characterized in that, The longitudinal cross-sectional shape of the trench is an inverted trapezoid.

5. The circuit board according to claim 3, characterized in that, The two conductive layers are a first conductive layer and a third conductive layer respectively, and a second conductive layer is further provided between the first conductive layer and the third conductive layer; a first insulating layer is provided between the first conductive layer and the second conductive layer, and a second insulating layer is provided between the second conductive layer and the third conductive layer; the second conductive layer is provided with signal lines.

6. The circuit board according to claim 5, characterized in that, The trench structure includes a first trench and a second trench respectively penetrating through the first insulating layer and the second insulating layer, and the second conductive layer is further provided with a connection pad insulated from the signal line; the connection pad electrically connects the conductive metal in the first trench and the conductive metal in the second trench respectively; or, A single trench of the trench structure simultaneously penetrates through the first insulating layer and the second insulating layer.

7. The circuit board according to any one of claims 1-6, characterized in that, The conductive metal is copper filled in the trench.

8. A method for manufacturing a circuit board, characterized in that, Including the steps of: Manufacturing a laminate including at least two power planes, and the at least two power planes include a first power plane and a second power plane; Forming at least one trench structure between the two power planes to connect the two power planes through the trench structure; Forming a conductive metal in the trench structure, the conductive metal filling the trench structure, and electrically connecting the two power planes through the conductive metal; Wherein, the cross-sectional area of the trench structure parallel to the surface of the circuit board is larger than the cross-sectional area of a common conductive via, so that the current-carrying capacity of the conductive metal in the current direction substantially perpendicular to the first power plane and the second power plane is greater than or equal to the current-carrying capacity of the first power plane in the current direction parallel to the first power plane; the cross-section of the trench structure parallel to the surface of the circuit board has dimensions in at least two dimensions, and at least one of the dimensions in the at least two dimensions is larger than the depth of the trench structure.

9. The method for manufacturing a circuit board according to claim 8, characterized in that, The trench structure is a single trench, or a trench group formed by stacking a plurality of trenches.

10. The method for manufacturing a circuit board according to claim 9, characterized in that, The manufacturing method of the trench structure includes: Form a single groove with a trapezoidal cross-sectional shape by means of laser grooving or mechanical controlled-depth milling, or form a groove group formed by stacking multiple grooves with trapezoidal cross-sectional shapes.

11. The method for manufacturing a circuit board according to claim 8, characterized in that, The laminate includes at least two power plane layers, and the manufacturing method for forming the groove structure specifically includes the steps: Provide a second insulating layer with a second conductive layer and a third conductive layer respectively coated on the upper and lower surfaces; Form at least one second groove penetrating through the second insulating layer, form the conductive metal in the second groove, and electrically connect the second conductive layer and the third conductive layer; Etch a second conductive pattern on the second conductive layer, and etch a third conductive pattern on the third conductive layer; the second conductive pattern includes a pad covering the second groove, and the third conductive pattern includes a second power plane electrically connected to the second groove; Laminate a first insulating layer and a first conductive layer on one side of the second conductive layer; Form two first grooves stacked above the second groove in the first insulating layer, form the conductive metal in the first grooves, and electrically connect the first conductive layer and the pad; Etch a first conductive pattern on the first conductive layer, and the first conductive pattern includes a first power plane electrically connected to the conductive metal in the two first grooves.

12. The method for manufacturing a circuit board according to claim 8, characterized in that,The laminate includes at least two power plane layers, and the manufacturing method for forming the groove structure specifically includes the steps: Provide a second insulating layer with a second conductive layer and a third conductive layer respectively coated on the upper and lower surfaces, etch a second conductive pattern on the second conductive layer, and etch a third conductive pattern on the third conductive layer. The second conductive pattern includes a blank area reserved for forming a groove, and the third conductive pattern includes a second power plane; Laminate a first insulating layer and a first conductive layer on one side of the second conductive layer; Form at least one groove penetrating through the first insulating layer and the second insulating layer at the blank area, form the conductive metal in the groove, and the conductive metal electrically connects the second power plane and the first conductive layer; Etch a first conductive pattern on the first conductive layer, and the first conductive pattern includes a first power plane electrically connected to the conductive metal.

13. The manufacturing method of the circuit board according to any one of claims 8 - 12, characterized in that, "Forming the conductive metal" specifically includes the steps: Deposit and fill a metal material in the groove to form the conductive metal.

14. The manufacturing method of the circuit board according to any one of claims 8 - 12, characterized in that, "Forming the conductive metal" specifically includes the steps: Embed a metal block or a metal sheet in the groove to form the conductive metal.

Images