Apparatus including circuit board and manufacturing method thereof

Abstract

The invention provides equipment comprising a circuit board and a manufacturing method thereof, which can be applied to the technical field of circuit boards. The apparatus includes: a multilayer circuit board stacked in a vertical direction and having an inclined side surface inclined with respect to the vertical direction; metal wires are arranged in the circuit board; the first metal wires of at least two layers of first circuit boards in the multilayer circuit board extend to the inclined side surfaces of the first circuit boards in the horizontal direction; and the first surface connecting part is positioned on the inclined side surface of the first circuit board and is connected with the end parts of the at least two layers of first metal wires. Therefore, the metal wires of different layers can be interconnected based on the surface connecting part extending on the inclined side surface, and the difficulty of manufacturing high-order HDI equipment is reduced, so that the high-order HDI equipment can be realized, and the interconnection effectiveness of each layer of metal wires in the equipment can be guaranteed.

Description

Technical Field

[0001] This application relates to the technical field of circuit boards, and particularly to an apparatus including a circuit board and a manufacturing method thereof. Background Art

[0002] The high-density interconnect (HDI) design of printed circuit boards (PCBs) emerged along with the requirements for miniaturization and multi-functionality of electronic devices. In related technologies, common HDI solutions include the sequential lamination method and the like. However, for a server including a circuit board, it is difficult to form a high-order HDI structure with a relatively large number of circuit board layers by such a method. Summary of the Invention

[0003] In view of the above problems, this application provides an apparatus including a circuit board and a manufacturing method thereof.

[0004] In a first aspect of this application, there is provided an apparatus including a circuit board, comprising: a multi-layer circuit board, stacked in a vertical direction and having an inclined side surface relative to the vertical direction; metal traces are provided in the circuit board; the first metal traces of at least two first circuit boards in the multi-layer circuit board extend horizontally to the inclined side surface of the first circuit board; a first surface connection portion, located on the inclined side surface of the first circuit board and connecting the ends of at least two first metal traces.

[0005] In a second aspect of this application, there is provided a method for manufacturing the above apparatus, comprising: forming a multi-layer circuit board stacked in a vertical direction and metal traces in the multi-layer circuit board; making the side surface of the multi-layer circuit board inclined relative to the vertical direction to form an inclined side surface of the multi-layer circuit board; wherein, the inclined side surfaces of at least two first circuit boards in the multi-layer circuit board expose the ends of at least two first metal traces; forming a first surface connection portion on the inclined side surface of the first circuit board such that the first surface connection portion connects the ends of at least two first metal traces.

[0006] According to an embodiment of the present application, a device including a circuit board is provided. At least two layers of first metal traces inside the device are simultaneously connected to a first surface connection portion on an inclined side surface of the first circuit board, and effective electrical connection is achieved via the first surface connection portion. In this way, when there are many levels of interconnected metal traces, the surface connection portion on the inclined side surface can ensure the effectiveness of the interconnection between metal traces of different layers. Based on this, since there is no need to fill vias in the circuit board to form a connection portion for connecting metal traces of different layers, the problem of difficulty in manufacturing high-order HDI devices due to difficult effective via filling in the related art is avoided, and the problem of via failure caused by the laser not punching through the hole is also avoided. In this way, the present application can interconnect metal traces of different layers based on the surface connection portion extending on the inclined side surface, reducing the difficulty of manufacturing high-order HDI devices, thereby enabling high-order HDI devices and ensuring the effectiveness of the interconnection of metal traces of each layer inside the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] To more clearly illustrate the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0008] Figure 1 A schematic diagram of a device according to a first embodiment of the present application is shown.

[0009] Figure 2A A flowchart of a method for manufacturing a device according to an embodiment of the present application is shown.

[0010] Figure 2B A cross-sectional view of a device according to a second embodiment of the present application in a manufacturing process is shown.

[0011] Figure 2C Shows a device according to a second embodiment of the present application located at Figure 2B A cross-sectional view of the device according to the second embodiment of the present application in a manufacturing process after the manufacturing process shown is shown.

[0012] Figure 2D Shows a device according to a second embodiment of the present application located at Figure 2C A cross-sectional view of the device according to the second embodiment of the present application in a manufacturing process after the manufacturing process shown is shown.

[0013] Figure 3 A schematic diagram of a device according to a third embodiment of the present application is shown.

[0014] Figure 4A A cross-sectional view of a device according to a fourth embodiment of the present application in a first horizontal direction is shown.

[0015] Figure 4B Shows a cross-sectional view of the device according to the fourth embodiment of the present application in the second horizontal direction.

[0016] Figure 5 Shows a cross-sectional view of the device according to the fifth embodiment of the present application in the first horizontal direction.

[0017] Figure 6A Shows a cross-sectional view of the device according to the sixth embodiment of the present application in the first horizontal direction.

[0018] Figure 6B Shows a cross-sectional view of the device according to the sixth embodiment of the present application in the second horizontal direction.

[0019] Figure 7A Shows a cross-sectional view of the device according to the seventh embodiment of the present application in the first horizontal direction.

[0020] Figure 7B Shows a cross-sectional view of the device according to the seventh embodiment of the present application in the second horizontal direction.

[0021] Figure 8 Shows a schematic diagram of the device according to the eighth embodiment of the present application.

[0022] Figure 9 Shows a schematic diagram of the device according to the ninth embodiment of the present application.

[0023] Figure 10 Shows a schematic diagram of the device according to the tenth embodiment of the present application.

[0024] Figure 11 Shows a schematic diagram of the device according to the eleventh embodiment of the present application.

[0025] Figure 12 Shows a schematic diagram of the device according to the twelfth embodiment of the present application.

[0026] Figure 13 Shows a flowchart of another method for manufacturing a device according to an embodiment of the present application.

[0027] Figure 14A Shows a cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process.

[0028] Figure 14B Shows that according to the thirteenth embodiment of the present application, the device is located at Figure 14A Shows a cross-sectional view of the device in the manufacturing process after the manufacturing process shown.

[0029] Figure 14C Shows that according to the thirteenth embodiment of the present application, the device is located at Figure 14BCross-sectional view in the manufacturing process after the shown manufacturing process.

[0030] Figure 14D Shows the device according to the thirteenth embodiment of the present application located at Figure 14C Cross-sectional view in the manufacturing process after the shown manufacturing process.

[0031] Figure 14E Shows the device according to the thirteenth embodiment of the present application located at Figure 14D Cross-sectional view in the manufacturing process after the shown manufacturing process.

[0032] Figure 14F Shows the device according to the thirteenth embodiment of the present application located at Figure 14E Cross-sectional view in the manufacturing process after the shown manufacturing process.

[0033] Figure 14G Shows the device according to the thirteenth embodiment of the present application located at Figure 14F Cross-sectional view in the manufacturing process after the shown manufacturing process. Detailed Description

[0034] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present application. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a thorough understanding of the embodiments of the present application. However, obviously, one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concepts of the present application.

[0035] The terms used herein are merely for describing specific embodiments and are not intended to limit the present application. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0036] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0037] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression (for example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0038] It should be noted that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the present application. The terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. The terms "parallel", "perpendicular", and "equal" include the described situations and situations similar to the described situations, and the range of the similar situations is within an acceptable deviation range, where the acceptable deviation range is determined by those of ordinary skill in the art considering the measurements being discussed and the errors associated with the measurements of specific quantities (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallel and approximate parallel, where the acceptable deviation range of approximate parallel can be, for example, within 5° deviation; "perpendicular" includes absolute perpendicular and approximate perpendicular, where the acceptable deviation range of approximate perpendicular can also be, for example, within 5° deviation. "Equal" includes absolute equality and approximate equality, where the acceptable deviation range of approximate equality can be, for example, that the difference between the two equal ones is less than or equal to 5% of either one of them. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0039] For server devices, generally, its dielectric constant (Dk) is about 3.7, the dielectric thickness of the circuit board of the device is about 4 - 5 mils (mils), and the thickness of the copper trace is about 1.2 mils. On this basis, designing the line width of the differential lines of the circuit board in the device to be 3 - 3.5 mils can make the impedance value of the circuit board 85 ohms, meeting the impedance requirements of the circuit board. However, in the case of a device using the sequential build-up method to form a high-order HDI, since the circuit boards of the device are thicker, the aspect ratio of the vias in the circuit board will be too high, making it difficult to effectively fill the vias using the electroplating process, resulting in the center top of the conductive material filled in the via being sunken relative to the inner wall of the via. As the order of the device increases, the problem of difficult effective via filling will become more serious, which will increase the difficulty of via filling in the process of forming the next-order HDI, and further make it difficult to achieve the high-order HDI of the server. For example, a high-order HDI can refer to an HDI of a circuit board with more than 8 stacked layers.

[0040] In view of this, the present application provides a device that can achieve effective interconnection of high-order HDI of metal traces on different layers.

[0041] Figure 1 A schematic diagram of a device according to a first embodiment of the present application is shown. It should be noted that for the convenience of schematically showing each metal trace in the device, Figure 1 other structures inside the device are not shown in. Similar to this, each of the following drawings described in the present application will not be elaborated here.

[0042] As Figure 1 shown, the device may include a plurality of circuit boards stacked in the vertical direction Z and metal traces disposed between the plurality of circuit boards. For example, the plurality of circuit boards include one or more first circuit boards with a first thickness W11, one or more second circuit boards with a second thickness W12 on the first circuit board, and one or more third circuit boards with a third thickness W13 on the second circuit board. For example, the plurality of circuit boards may include a first-layer circuit board 111_L1 with a first thickness, a second-layer circuit board 111_L2 with a second thickness on the first-layer circuit board, and a third-layer circuit board 111_L3 with a third thickness on the second-layer circuit board. It should be understood that this is only an example, and in the embodiments of the present application, a fourth circuit board with a fourth thickness, a fifth circuit board with a fifth thickness, etc. may also be included.

[0043] The metal traces between multiple circuit boards may include at least two layers of metal traces. The at least two layers of metal traces may include a first layer of metal trace 121_I1 and a second layer of metal trace 121_I2. Among them, the multiple circuit boards and the multiple metal traces may extend in the horizontal direction. The horizontal direction may be the first horizontal direction X or the second horizontal direction Y, and this application does not limit this.

[0044] Any two layers of the at least two layers of metal traces may be connected via a connection portion located between the any two layers of metal traces. For example, the connection portion may be an in-board connection portion and may be formed by a conductive material in a via hole in the circuit board. Specifically, the first layer of metal trace 121_I1 and the second layer of metal trace 121_I2 may be connected via the connection portion 121_S. The second layer of metal trace 121_I2 and the connection portion 121_S may be formed together by an electroplating process. Continuing to refer Figure 1 it can be seen that the center top of the connection portion 121_S, that is, the center top of the conductive material in the via hole, is recessed relative to the top of the inner wall of the via hole. This recess will increase the difficulty of filling the hole during the process of manufacturing the next-stage connection portion. Thus, as the number of interconnected stages increases, the difficulty of filling the hole also increases, increasing the risk of product scrapping, thereby limiting the HDI order of products such as servers and making it difficult to achieve high-order HDI interconnection of products such as servers.

[0045] In response to this, in this application, by controlling the first thickness W11, the second thickness W12, and the third thickness W13 of the above-mentioned respective circuit boards to decrease successively in the vertical direction Z, the thickness of the multiple circuit boards is thinned layer by layer in the vertical direction Z. It is possible to improve the drilling quality and filling quality of each stage of the circuit board while ensuring impedance matching of the device, reduce the difficulty of filling the hole, and thus achieve high-order HDI interconnection. It should be understood that the fourth circuit board with a fourth thickness on the third circuit board with a third thickness and the fifth circuit board with a fifth thickness on the fourth circuit board, etc., may also be thinned layer by layer, which will not be elaborated here. Among them, when parameters such as the dielectric constant of the circuit board, the line width of the metal trace, and the line pitch of the metal trace are fixed, the thickness of the circuit board may be positively correlated with the impedance.

[0046] On this basis, Figure 2A shows a flowchart of a method for manufacturing a device according to an embodiment of this application. As Figure 2A shown, the method for manufacturing the device in this embodiment includes operation S210.

[0047] In operation S210, multiple circuit boards stacked in the vertical direction, metal traces between the multiple circuit boards, and connection portions connecting at least two layers of metal traces are formed.

[0048] Figure 2BShows a cross-sectional view of the device according to the second embodiment of the present application in a manufacturing process, Figure 2C Shows the device according to the second embodiment of the present application located in Figure 2B A cross-sectional view of the manufacturing process after the manufacturing process shown, Figure 2D Shows the device according to the second embodiment of the present application located in Figure 2C A cross-sectional view of the manufacturing process after the manufacturing process shown.

[0049] As Figure 2B shown, in the embodiment of the present application, vias extending in the vertical direction Z and passing through the circuit board can be formed on any circuit board. For example, a pattern of vias can be formed on the second-layer circuit board by a dry film process, and then the second circuit board can be drilled using a laser to form the first via 131_1. For the convenience of comparison, the second via 131_2 on the third-layer circuit board is also shown in Figure 2B . It should be understood that this is only for illustration. In another implementation of the present application, the first via 131_1 and the second via 131_2 can be formed in different process flows successively. The first via 131_1 can partially expose the upper surface of the metal traces on the first-layer circuit board. The second via 131_2 can partially expose the upper surface of the metal traces on the second-layer circuit board.

[0050] Continuing to refer to Figure 2B , it can be seen that the inner walls of the vias of different circuit boards at different heights are inclined at different angles with respect to the vertical direction Z. For example, the inner wall of the first via 131_1 is inclined at a first angle ∠1 with respect to the vertical direction Z, and the inner wall of the second via 131_2 is inclined at a second angle ∠2 with respect to the vertical direction Z. Among them, since the third thickness W13 is less than the second thickness W12, the quality of the via 131_2 formed in the third-layer circuit board 111_L3 is better than that of the second-layer circuit board 111_L2. Therefore, the second angle ∠2 is less than the first angle ∠1.

[0051] Referring to Figure 2B - 2C, a connection portion formed in the via and metal traces on the circuit board can be formed through an electroplating process. For example, a first connection portion 121_S1 formed inside the first via 131_1 and a first metal trace 121_I3 on the upper surface of the second-layer circuit board can be formed using the electroplating process. Also, a second connection portion 121_S2 formed inside the second via 131_2 and a second metal trace 121_I4 on the upper surface of the second-layer circuit board can be formed using the electroplating process. It can be seen that since the inclination angles of the inner sidewalls of the vias of the circuit boards at different heights with respect to the vertical direction Z are different, the contact interfaces (i.e., the contact interfaces that are in contact with the inner sidewalls of the vias) of the connection portions in the vias of different circuit boards with respect to the circuit boards have different inclination angles with respect to the vertical direction Z. The inclination angle of the contact plane of the connection portion in the circuit board is positively correlated with the thickness of the circuit board, that is, the thicker the circuit board, the larger the inclination angle of the contact plane. Thus, in an embodiment of the present application, since the thickness of the multi-layer circuit board decreases layer by layer in the vertical direction Z, the inclination angles of the second connection portions at different heights also show a decreasing trend in the vertical direction Z.

[0052] Reference Figure 2B - 2D , a new circuit board, such as a fourth-layer circuit board 111_L4, can be formed on the third-layer circuit board 111_L3. For the convenience of illustration, in Figure 2B - 2D , the part of the third-layer circuit board 111_L3 in the horizontal direction is filled, so that the left side of the third-layer circuit board 111_L3 is flush with the left sides of other circuit boards in the vertical direction Z, and the third-layer circuit board and the fourth-layer circuit board after filling the vias are shown. It should be understood that the structure of the via after filling the via here is only for illustration and is not used to limit the actual structure of the present application. In Figure 2B - 2D , the center top of any one of the plurality of connection portions is concave with respect to the top of the inner sidewall of the via of any one of the connection portions. The degree of concavity of any one of the connection portions is positively correlated with the thickness of the circuit board where the connection portion is located. For example, the fourth-layer circuit board is thinner than the third-layer circuit board, so that the concave distance D2 of the fourth-layer circuit board is smaller than the concave distance of the connection portion in the third-layer circuit board D1. Thus, the degree of concavity of the tops of the connection portions of the plurality of circuit boards can be gradually reduced from bottom to top, so that when the number of layers of the circuit board increases, the difficulty of filling the vias can be reduced, and thus the interconnection of high-order HDI can be achieved.

[0053] However, in some cases, due to the relatively thick dielectric of the circuit board, it may be difficult to penetrate the dielectric of the circuit board during the process of using a laser to drill holes in the dielectric of the circuit board. In the circuit board, since the laser fails to penetrate the dielectric inside the circuit board, ineffective holes are formed. Thus, metal traces at different heights cannot be interconnected. There are thousands or even tens of thousands of laser holes in each layer of the connection part on a single product, and the failure of any one hole will cause the product to fail, resulting in the scrapping of the product. Thus, it will increase the resources consumed by the equipment for manufacturing high-order HDI and increase the processing cycle. On this basis, the present application proposes another device that can solve this problem and achieve effective interconnection of metal traces on any layer in the high-order HDI equipment.

[0054] Figure 3 Fig. shows a schematic diagram of the device according to the third embodiment of the present application.

[0055] As Figure 3 shown, the device of this embodiment may include multiple circuit boards stacked in the vertical direction Z and metal traces provided in the multiple circuit boards. Among them, the multiple circuit boards may have inclined side surfaces inclined with respect to the vertical direction Z. The circuit board may have an inclined side surface facing the horizontal direction, such as at least one of an inclined side surface facing the first horizontal direction X or an inclined side surface facing the second horizontal direction Y. Among them, the first horizontal direction X intersects (e.g., is perpendicular to) the second horizontal direction Y. For example, the multiple circuit boards may include at least two first circuit boards L1. The first circuit board L1 has an inclined side surface inclined at a first angle F1 with respect to the vertical direction Z. For example, the upper surface (i.e., the upper surface of the uppermost circuit board) and the lower surface (i.e., the lower surface of the lowermost circuit board) of the device may extend in the first horizontal direction X and the second horizontal direction Y. The inclined side surface of the first circuit board L1 may extend obliquely with respect to the lower surface. This inclined side surface may form an acute angle with the lower surface of the device. In this case, the angle formed by this inclined side surface and the lower surface is complementary to the first angle F1. And the embodiment of the present application is not limited to this. This inclined side surface may also form an obtuse angle with the lower surface of the circuit board. In this case, the angle formed by this inclined side surface and the lower surface differs from the first angle F1 by 90°.

[0056] The at least two layers of the first circuit board L1 described above may include at least two layers of first metal traces I1. The first metal traces I1 extend in a horizontal direction (e.g., at least one of the first horizontal direction X and the second horizontal direction Y) to the inclined side surface of the first circuit board L1. In addition, the connection portion in the embodiment of the present application is not limited to the connection portion formed based on vias described above, and further includes a surface connection portion extending on the inclined side surface. The interface where the surface connection portion contacts the circuit board may also have a certain angle relative to the vertical direction. The device in this embodiment may further include a first surface connection portion S1 on the inclined side surface of the first circuit board L1. The first surface connection portion S1 connects the ends of at least two layers of first metal traces I1, so as to be in electrical contact with the ends of at least two layers of first metal traces I1 respectively. For example, the first surface connection portion S1 may at least partially cover the ends of at least two layers of first metal traces I1. In this way, at least two layers of first metal traces I1 can be electrically connected via the first surface connection portion S1. It should be understood that the number of metal traces, surface connection portions, and circuit boards shown in Figure 3 is only illustrative, and other embodiments of the present application may also include other numbers of metal traces, surface connection portions, and circuit boards.

[0057] Based on this, at least two layers of first metal traces I1 inside the device are simultaneously connected to the first surface connection portion S1 on the inclined side surface of the first circuit board L1, and effective electrical connection is achieved via the first surface connection portion S1. In this way, in the case where the number of levels of interconnected metal traces is large, the surface connection portion on the inclined side surface can ensure the effectiveness of the interconnection between metal traces of different layers. Based on this, since there is no need to fill the vias in the circuit board to form a connection portion for connecting metal traces of different layers, the problem of difficulty in manufacturing high-order HDI devices caused by difficult effective filling of vias in the related art is avoided, and the problem of via failure caused by the laser not punching through the holes is avoided. In this way, the present application can interconnect metal traces of different layers based on the surface connection portion extending on the inclined side surface, reduce the difficulty of manufacturing high-order HDI devices, thereby realizing high-order HDI devices, and can ensure the effectiveness of the interconnection of metal traces of each layer inside the device.

[0058] On this basis, continue to refer to Figure 3, the angular value of the first angle F1 can be determined at least in part by the thickness of at least two layers of the first circuit board L1 and the number of layers of at least two layers of the first metal traces I1. For example, when the thickness of at least two layers of the first circuit board L1 is fixed, the angular value of the first angle F1 is positively correlated with the number of layers of at least two layers of the first metal traces I1. For example, the number of layers of the first circuit board L1 is greater than or equal to 2, and at least two layers of the first circuit board L1 can be stacked in sequence in the vertical direction Z. And at least two layers of the first metal traces I1 can be respectively located on the first circuit boards L1 at different heights. In this case, the more the number of layers of at least two layers of the first metal traces I1, that is, the more the number of layers of the first metal traces I1 distributed on different layers in the vertical direction Z, the greater the angular value of the first angle F1, so that the inclined side surfaces of at least two layers of the first circuit board L1 can expose more ends of the first metal traces I1, so that the first metal traces I1 with exposed ends can be electrically connected as much as possible on the inclined side surfaces of the first circuit board L1.

[0059] For example, the first distance between the end of the uppermost first metal trace I1 in at least two layers of the first metal traces I1 close to the inclined side surface of the first circuit board L1 and the end of the lowermost first metal trace I1 close to the inclined side surface of the first circuit board L1 can be determined, and this first distance can be used as the hypotenuse length in the sine formula. And the second distance closest to each other in the vertical direction Z between the uppermost first metal trace I1 and the lowermost first metal trace I1 can be determined, and this second distance can be used as the opposite side length in the sine formula. Then, the first distance and the second distance can be processed using the sine formula to obtain a sine value, so as to determine the angular value between the inclined side surface and the lower surface of the device according to the sine value, and thus the angular value of the first angle F1 can be determined.

[0060] In addition, in addition to the step-by-step lamination method, in some examples, methods such as full lamination can also be used to achieve high-order HDI interconnection. In this way, conductive materials such as conductive paste or copper need to be filled in the vias, and signal reflection will occur at the position of the conductive paste or copper, which is difficult to meet the transmission requirements of high-speed signals, and the yield rate of the manufacturing equipment of this method is relatively low. In this regard, in some embodiments of the present application, the first surface connection portion S1 and the first metal trace I1 can include the same material. For example, the first surface connection portion S1 and the first metal trace I1 can include the same metal material, such as copper and the like. In this way, signal reflection can be reduced relative to the related art, so as to improve the transmission quality of high-speed signals.

[0061] Moreover, since the above-mentioned ends of at least two layers of the first metal traces I1 are electrically connected via the first surface connection portion S1, at least two layers of the first metal traces I1 are not electrically connected via the conductive material filled in the vias. In this way, the dielectric thickness can be increased, thereby improving the dielectric impedance without affecting the interconnection quality. On this basis, a new inclined side surface of the device can be formed and a new surface connection portion can be formed on the new inclined side surface to increase the number of metal traces for interconnection. Alternatively, a new surface connection portion can be formed on the original inclined side surface, and the metal traces with exposed ends on the original inclined side surface can be interconnected via the new surface connection portion, thereby increasing the number of metal traces for interconnection. The following will be described in conjunction with Figure 4A and Figure 4B for illustration.

[0062] Figure 4A shows a cross-sectional view of the device according to the fourth embodiment of the present application in the first horizontal direction. Figure 4B shows a cross-sectional view of the device according to the fourth embodiment of the present application in the second horizontal direction. It should be added that Figure 4A shows the contact interfaces where the circuit boards are in contact with each other, while in Figure 4B for the sake of simplicity in illustration, the contact interfaces where the circuit boards are in contact with each other are not shown, but the upper surface interface of the step that is visible only in the right view in Figure 4A is shown. The same applies to the various drawings described below in the present application, and will not be elaborated further hereinafter.

[0063] Referring to Figure 4A and Figure 4B , in the device of this embodiment, the multi-layer circuit board may include at least two layers of the first circuit board L1 and at least two layers of the second circuit board L2. The first circuit board L1 has an inclined side surface that is inclined at a first angle F1 with respect to the vertical direction Z. The second circuit board L2 has an inclined side surface that is inclined at a second angle F2 with respect to the vertical direction Z, and the first angle F1 and the second angle F2 may be different angles. In this way, the device of the present application can simultaneously have inclined side surfaces with multiple inclination angles, so that different surface connection portions can be formed on the inclined side surfaces with different inclination angles, thereby enabling flexible and arbitrary interconnection of high-order HDI.

[0064] The metal traces disposed inside the multi-layer circuit board may include at least two layers of first metal traces I1 and at least two layers of second metal traces I2. The first metal traces I1 extend horizontally to the inclined side surface of the first circuit board L1. The second metal traces I2 extend horizontally to the inclined side surface of the second circuit board L2. The first metal traces I1 and the second metal traces I2 may be in different regions of the multi-layer circuit board. For example, the different regions may be divided based on height, and the first metal traces I1 and the second metal traces I2 may be at different heights in the vertical direction. Correspondingly, the first surface connection portion S1 and the second surface connection portion S2 may be at different heights in the vertical direction.

[0065] The device of this embodiment may further include a first surface connection portion S1 extending on the inclined side surface of the first circuit board L1 and a second surface connection portion S2 extending on the inclined side surface of the second circuit board L2. The first surface connection portion S1 is between at least two layers of the first metal traces I1 in the vertical direction Z and is connected to the ends of at least two layers of the first metal traces I1, so as to be in electrical contact with at least two layers of the first metal traces I1. In this way, at least two layers of the first metal traces I1 can be electrically connected via the first surface connection portion S1. Similarly, the second surface connection portion S2 is between at least two layers of the second metal traces I2 in the vertical direction Z and is connected to the ends of at least two layers of the second metal traces I2, so as to be in electrical contact with at least two layers of the second metal traces I2. In this way, at least two layers of the second metal traces I2 can be electrically connected via the second surface connection portion S2. It should be understood that the number of metal traces, surface connection portions, and circuit boards shown in Figure 4A and Figure 4B is only illustrative, and in other embodiments of the present application, there may also be other numbers of metal traces, surface connection portions, and circuit boards.

[0066] Based on this, surface connection portions with different heights can be arbitrarily formed on different inclined side surfaces of different circuit boards, and the surface connection portions with different heights can each interconnect some of the metal traces in the multi-layer metal traces, so that effective interconnection of any at least two layers of metal traces can be achieved. In addition, the device may also include other metal traces that are not in electrical contact with the first surface connection portion S1 and the second surface connection portion S2, etc. It should be understood that the present application is not limited to Figure 4A and Figure 4B the two surface connection portions shown. According to needs, more surface connection portions may also be provided on the inclined side surfaces of the device to achieve the interconnection of metal traces.

[0067] Continuing to refer to Figure 4A and Figure 4B, in an embodiment of the present application, the metal traces disposed inside the multi-layer circuit board may include metal traces for transmitting different types of signals. The metal traces for transmitting different types of signals may be in different regions, that is, the above-mentioned first metal trace I1 and the second metal trace I2 may be used to transmit different types of signals. For example, at least two layers of the first metal trace I1 are in the first region in the vertical direction Z, and at least two layers of the second metal trace are in the second region in the vertical direction Z. Specifically, the metal traces in the first region may be used to transmit power supply signals. The metal traces in the second region may be used to transmit data signals different from the power supply signals. Another example is that the metal traces in the first region may be used to transmit high-speed signals such as Peripheral Component Interconnect express (PCIe) signals. The metal traces in the second region may be used to transmit low-speed signals with a lower speed than the PCIe signals. It should be understood that this is only an example, and the present application is not limited thereto. In another embodiment of the present application, in addition to dividing regions by height, regions may also be divided by horizontal position, and the present application does not limit this.

[0068] In addition, in the embodiments of the present application, the end of the first metal trace may have an interface flush with the inclined side surface of the first circuit board. On this basis, the first surface connection portion is connected to at least two layers of the first metal traces via the interfaces of at least two layers of the first metal traces. Similarly, the end of the second metal trace may have an interface flush with the inclined side surface of the second circuit board. On this basis, the second surface connection portion is connected to at least two layers of the second metal traces via the interfaces of at least two layers of the second metal traces. The area of the interface of the first metal trace is different from the area of the interface of the second metal trace. In one implementation, the inclined side surfaces of the first circuit board and the second circuit board may be formed by a milling process. Thus, the larger the milling angle, the larger the area of the end interface of the metal trace exposed via the side surface. Specifically, the inclined side surface of the first circuit board is inclined at a first angle with respect to the vertical direction, and the inclined side surface of the second circuit board is inclined at a second angle with respect to the vertical direction. When the first angle is greater than the second angle, the area of the interface at the end of the first metal trace is greater than the area of the interface at the end of the second metal trace. When the first angle is less than the second angle, the area of the interface at the end of the first metal trace is less than the area of the interface at the end of the second metal trace. On this basis, different surface connection portions can be used for interconnection on different inclined side surfaces, so as to realize a high-order HDI structure. Further, the first angle may be greater than 0° and less than 90°; the second angle may be greater than 0° and less than 90°. For example, after the milling process, processes such as laser patterning and electroplating are required to form the surface connection portion on the inclined side surface. If the angle is greater than or equal to 90°, it is difficult to be compatible with processes such as laser processing and electroplating to implement the surface connection portion provided on the inclined side surface, thus it is difficult to realize the high-order HDI structure of the present application. And if the angle is equal to 0°, there is no need to use processes such as laser patterning and electroplating to form the surface connection portion on the inclined side surface, and the traces extending in the horizontal direction can be directly formed. Thus, designing the inclination angle of the inclined side surface to be 0° to 90° can realize the concept of the inclined surface high-order HDI structure of the present application.

[0069] Figure 5 Fig. 4 shows a cross-sectional view of the device according to the fifth embodiment of the present application in the first horizontal direction.

[0070] Refer to Figure 5 , in the device of this embodiment, the multi-layer circuit board may also include at least two layers of the first circuit board L1 and at least two layers of the second circuit board L2. The first circuit board L1 has an inclined side surface inclined at a first angle with respect to the vertical direction Z. For example, the inclined side surface of the first circuit board L1 may include an inclined side surface in a first orientation and an inclined side surface in a second orientation different from the first orientation. Specifically, the first circuit board L1 may have an inclined side surface facing Figure 5 to the left inFigure 5 The inclined side surface on the right side in the [description]. It should be understood that in the embodiments of the present application, the specific directions of the first orientation and the second orientation are not limited, nor is the number of inclined side surfaces of the first circuit board L1 facing different directions limited. For example, the first circuit board L1 may also have an inclined side surface facing the second horizontal direction Y, and so on. Similarly, the second circuit board L2 has an inclined side surface that is inclined at a second angle with respect to the vertical direction Z in the horizontal direction, and the first angle and the second angle may be different angles. For example, the inclined side surfaces of the second circuit board may include an inclined side surface in the first orientation and an inclined side surface in the second orientation. For example, the second circuit board may also have an inclined side surface facing Figure 5 the inclined side surface on the left side in the [description] and facing Figure 5 the inclined side surface on the right side in the [description]. It should be understood that in the embodiments of the present application, the number of inclined side surfaces of the second circuit board L2 facing different directions is also not limited. For example, the second circuit board L2 may also have an inclined side surface facing the second horizontal direction Y, and so on.

[0071] The metal traces disposed inside the multi-layer circuit board may include at least two layers of first metal traces I1 and at least two layers of second metal traces I2. The first metal traces I1 extend in the horizontal direction to the inclined side surface of the first circuit board L1. The second metal traces I2 extend in the horizontal direction to the inclined side surface of the second circuit board L2. For example, the inclined side surface of the first circuit board L1 to which the first metal traces I1 extend and the inclined side surface of the second circuit board L2 to which the second metal traces extend may have the same or different orientations. In Figure 5 the example shown, the inclined side surface of the first circuit board L1 to which the first metal traces I1 extend and the inclined side surface of the second circuit board L2 to which the second metal traces extend have different orientations.

[0072] The device of this embodiment may also include a first surface connection portion S1 extending on the inclined side surface on one side of the first circuit board L1 and a second surface connection portion S2 extending on the inclined side surface on one side of the second circuit board L2. For example, the inclined side surface of the first circuit board L1 where the first surface connection portion S1 is located and the inclined side surface of the second circuit board where the second surface connection portion S2 is located may have the same or different orientations. In Figure 5 the example shown, the inclined side surface of the first circuit board L1 where the first surface connection portion S1 is located and the inclined side surface of the second circuit board where the second surface connection portion S2 is located have different orientations.

[0073] On this basis, the first surface connection portion S1 is located between at least two layers of the first metal traces I1 in the vertical direction Z and is connected to one side end of at least two layers of the first metal traces I1, so as to be in electrical contact with at least two layers of the first metal traces I1. In this way, at least two layers of the first metal traces I1 can be electrically connected via the first surface connection portion S1. Similarly, the second surface connection portion S2 is located between at least two layers of the second metal traces I2 in the vertical direction Z and is connected to one side end of at least two layers of the second metal traces I2, so as to be in electrical contact with at least two layers of the second metal traces I2. In this way, at least two layers of the second metal traces I2 can be electrically connected via the second surface connection portion S2. It should be understood that the number of metal traces, surface connection portions, and circuit boards shown in Figure 5 is only illustrative, and in other embodiments of the present application, there may also be other numbers of metal traces, surface connection portions, and circuit boards.

[0074] Based on this, referring to Figure 5 it can be seen that surface connection portions can be respectively formed on side surfaces with different orientations. The surface connection portions on inclined side surfaces with different orientations and different heights can each interconnect some of the metal traces in the multi-layer metal traces. In this way, effective interconnection of any at least two layers of metal traces is achieved on different side surfaces.

[0075] Figure 6A shows a cross-sectional view of the device according to the sixth embodiment of the present application in the first horizontal direction X, Figure 6B shows a cross-sectional view of the device according to the sixth embodiment of the present application in the second horizontal direction Y.

[0076] Referring to Figure 6A and Figure 6B , in the device of this embodiment, the multi-layer circuit board may include at least two layers of the first circuit board L1 and at least two layers of the second circuit board L2. The first circuit board L1 has an inclined side surface that is inclined at a first angle with respect to the vertical direction Z. The second circuit board L2 has an inclined side surface that is inclined at a second angle with respect to the vertical direction Z, and the first angle and the second angle may be different angles. The metal traces disposed inside the multi-layer circuit board may include at least two layers of the first metal traces I1 and at least two layers of the second metal traces I2. The first metal traces I1 extend horizontally to the inclined side surface of the first circuit board L1. The second metal traces I2 extend horizontally to the inclined side surface of the second circuit board L2.

[0077] The device of this embodiment may further include a first surface connection portion S1 extending on the inclined side surface of the first circuit board L1 and a second surface connection portion S2 extending on the inclined side surface of the second circuit board L2. The first surface connection portion S1 is located between at least two layers of first metal traces I1 in the vertical direction Z and is connected to one side end of at least two layers of first metal traces I1, so as to be in electrical contact with at least two layers of first metal traces I1. In this way, at least two layers of first metal traces I1 can be electrically connected via the first surface connection portion S1. Similarly, the second surface connection portion S2 is located between at least two layers of second metal traces I2 in the vertical direction Z and is connected to one side end of at least two layers of second metal traces I2, so as to be in electrical contact with at least two layers of second metal traces I2. In this way, at least two layers of second metal traces I2 can be electrically connected via the second surface connection portion S2.

[0078] In addition, the device of this embodiment may further include a third surface connection portion S3. The third surface connection portion S3 may extend on the upper surface of the uppermost circuit board in the multi-layer circuit board and be connected to one of the first surface connection portion S1 and the second surface connection portion S2, so as to form a continuous integral structure. For example, in Figure 6A and Figure 6B , the third surface connection portion S3 is in electrical contact with the second surface connection portion S2 and forms a continuous integral structure with the second surface connection portion S2. In this way, the second surface connection portion S2 can be electrically connected to other structures via the third surface connection portion S3 on the upper surface of the device. For example, the other structures here may be devices provided on the upper surface of the device ( Figure 6A and Figure 6B are not shown). Since the second surface connection portion S2 and the third surface connection portion S3 extend on the inclined side surface of the second circuit board L2 and the upper surface of the device respectively, there is an angle towards the circuit board between the second surface connection portion S2 and the third surface connection portion S3. For example, this angle may be an obtuse angle. The embodiments of the present application are not limited to this. In some embodiments, this angle may also be an acute angle. It should be understood that in this embodiment, this angle and the angle of the inclined side surface relative to the lower surface of the device described above may be complementary.

[0079] Based on this, referring to Figure 6A and Figure 6B , it can be seen that at least one of the first surface connection portion S1 and the second surface connection portion S2 on the side surface can be extended via the third surface connection portion S3 to be connected to the device on the upper surface of the device, so that effective interconnection of devices in different layers is realized on both the inclined side surface and the upper surface. In addition, other metal traces that are not in electrical contact with the first surface connection portion S1 and the second surface connection portion S2 may be included in the device. It should be understood that the present application is not limited to Figure 6A andFigure 6B Among the three surface connection parts shown, more surface connection parts can also be provided on the inclined side surface of the device to realize the interconnection of metal traces as needed.

[0080] Figure 7A Fig. shows a cross-sectional view of the device according to the seventh embodiment of the present application in the first horizontal direction. Figure 7B Fig. shows a cross-sectional view of the device according to the seventh embodiment of the present application in the second horizontal direction.

[0081] Referring to Figure 7A and Figure 7B , in the device of this embodiment, the multi-layer circuit board may include at least two layers of first circuit boards L1 and at least two layers of second circuit boards L2. The first circuit board L1 has an inclined side surface inclined at a first angle with respect to the vertical direction Z. The second circuit board L2 has an inclined side surface inclined at a second angle with respect to the vertical direction Z, and the first angle and the second angle may be different angles. The metal traces provided inside the multi-layer circuit board may include at least two layers of first metal traces I1 and at least two layers of second metal traces I2. The first metal traces I1 extend horizontally to the inclined side surface of the first circuit board L1. The second metal traces I2 extend horizontally to the inclined side surface of the second circuit board L2.

[0082] The device of this embodiment may further include a first surface connection part S1 extending on the inclined side surface of the first circuit board L1 and a second surface connection part S2 extending on the inclined side surface of the second circuit board L2. The first surface connection part S1 is located between at least two layers of first metal traces I1 in the vertical direction Z and is connected to one end of at least two layers of first metal traces I1, so as to be in electrical contact with at least two layers of first metal traces I1. In this way, at least two layers of first metal traces I1 can be electrically connected via the first surface connection part S1. Similarly, the second surface connection part S2 is located between at least two layers of second metal traces I2 in the vertical direction Z and is connected to one end of at least two layers of second metal traces I2, so as to be in electrical contact with at least two layers of second metal traces I2. In this way, at least two layers of second metal traces I2 can be electrically connected via the second surface connection part S2.

[0083] In addition, the device of this embodiment may further include a third surface connection part S3, in Figure 7A and Figure 7B , the third surface connection part S3 is in electrical contact with both the first surface connection part S1 and the second surface connection part S2 and forms a continuous integral structure with the first surface connection part S1 and the second surface connection part S2. In this way, the first surface connection part S1 and the second surface connection part S2 can be electrically connected to other structures via the third surface connection part S3 on the upper surface of the device.

[0084] Continuing to refer toFigure 7A , the multi-layer circuit board may further include at least two layers of third circuit boards L3. Each of the at least two layers of third circuit boards L3 includes vias filled with conductive material. The third metal traces I3 of the at least two layers of third circuit boards L3 can be electrically connected via the conductive material filled in the vias. Among them, the inner sidewalls of the vias of the at least two layers of third circuit boards L3 are inclined relative to the vertical direction Z. The inclination angle of the inner sidewall of the via of the upper third circuit board L3 among the at least two layers of third circuit boards L3 is smaller than the inclination angle of the inner sidewall of the via of the lower third circuit board L3, and the thickness of the upper third circuit board is thinner than the thickness of the lower third circuit board. Correspondingly, if the thickness of the upper third circuit board is thicker than the thickness of the lower third circuit board, the inclination angle of the inner sidewall of the via of the upper third circuit board L3 is greater than the inclination angle of the inner sidewall of the via of the lower third circuit board L3. For example, the center top of the conductive material in the via of the upper third circuit board L3 has a first concave distance relative to the top of the inner sidewall of the via of the upper third circuit board L3. The center top of the conductive material in the via of the lower third circuit board L3 has a second concave distance relative to the top of the inner sidewall of the via of the lower third circuit board L3. The first concave distance is less than the second concave distance. On this basis, by controlling the thickness of the multi-layer third circuit board L3 to gradually decrease from bottom to top, while making the impedance of the multi-layer third circuit board meet the impedance conditions of the device, the drilling quality can be improved, so that the included angle between the inner sidewall of the via and the vertical direction gradually decreases, thereby improving the quality of filling the via with conductive material, reducing the degree of concave of the conductive material relative to the inner sidewall of the via, reducing the difficulty of forming high-order HDI due to the depression of the conductive material, and thus a high-order HDI can be manufactured. Specifically, the first concave distance can be 0 to 1.5 mil, and the second concave distance can be 0 to 1.5 mil. For example, when the thickness of the circuit board is 4 mil, the concave distance can be 1.5 mil; when the thickness of the circuit board is 3.5 mil, the concave distance can be 1.2 mil; when the thickness of the circuit board is 3 mil, the concave distance can be 0.8 mil; when the thickness of the circuit board is 2.5 mil, the concave distance can be 0.3 mil; when the thickness of the circuit board is 2 mil, the concave distance can be 0 mil. It can be seen from this that the difference in the thickness of the circuit board changing layer by layer can be less than the difference in the distance of the concave distance changing layer by layer. A concave distance of 1.5 mil can ensure the usability of the device and avoid the scrapping of the device. On this basis, the concave distance of the conductive material in the at least two layers of third circuit boards gradually decreases starting from 1.5 mil and can finally be reduced to 0, making the via filling quality reach the best and minimizing the difficulty of manufacturing high-order HDI as much as possible.

[0085] It should be further noted that although in this embodiment, the first surface connection portion S1, the second surface connection portion S2, the third surface connection portion S3 and the connection portion formed based on the via holes appear simultaneously, this does not limit the embodiments of the connection portions in the present application. That is, in the embodiments regarding other drawings, connection portions that do not appear in the embodiments of other drawings can also be provided. That is, the embodiments of the present application can be arbitrarily combined as long as those skilled in the art can implement them. For example, in the device of an embodiment of the present application, the three-layer third metal trace I3 is electrically connected via two vias with different heights. Then, the device of this embodiment can also be applicable to the features such as multiple circuit boards that are sequentially thinned in the vertical direction described above to achieve the purpose described above in the present application, which will not be elaborated here.

[0086] Figure 8 FIG. shows a schematic diagram of a device according to the eighth embodiment of the present application.

[0087] Reference Figure 8 , in the device of this embodiment, the multi-layer circuit board may include at least two layers of first circuit boards L1 and at least two layers of second circuit boards L2. The first circuit board L1 has an inclined side surface that is inclined at a first angle F1 with respect to the vertical direction Z. For example, the inclined side surface of the first circuit board L1 may include an inclined side surface facing a first direction and an inclined side surface facing a second direction. For example, the first circuit board L1 may have an inclined side surface facing Figure 8 the left side in Figure 8 and an inclined side surface facing

[0088] the right side in. Similarly, the second circuit board L2 has an inclined side surface that is inclined at a second angle with respect to the vertical direction Z. For example, the inclined side surface of the second circuit board may include an inclined side surface facing a first direction and an inclined side surface facing a second direction different from the first direction. In this embodiment, the second circuit board L2 may simultaneously have an inclined side surface with the same inclination angle as the inclined side surface of the first circuit board L1, and an inclined side surface with an inclination angle different from the inclined side surface of the first circuit board L1.

[0089] The device of this embodiment may further include a first surface connection portion S1 extending on an inclined side surface of one side of the first circuit board L1 and a second surface connection portion S2 extending on an inclined side surface of one side of the second circuit board L2. In this embodiment, the inclined side surface of the first circuit board L1 where the first surface connection portion S1 is located has a different orientation from the inclined side surface of the second circuit board where the second surface connection portion S2 is located, and the inclined angles are also different.

[0090] On this basis, the first surface connection portion S1 is located between at least two layers of first metal traces I1 in the vertical direction Z and is connected to one side end portions of at least two layers of first metal traces I1, so as to be in electrical contact with at least two layers of first metal traces I1. In this way, at least two layers of first metal traces I1 can be electrically connected via the first surface connection portion S1. Similarly, the second surface connection portion S2 is located between at least two layers of second metal traces I2 in the vertical direction Z and is connected to one side end portions of at least two layers of second metal traces I2, so as to be in electrical contact with at least two layers of second metal traces I2. In this way, at least two layers of second metal traces I2 can be electrically connected via the second surface connection portion S2.

[0091] In addition, the device of this embodiment may further include a third surface connection portion S3. The third surface connection portion S3 may extend on the upper surface of the uppermost circuit board in the multi-layer circuit board and form a continuous integral structure together with the first surface connection portion S1 and the second surface connection portion S2. In this way, the first surface connection portion S1 and the second surface connection portion S2 can be electrically connected to other structures via the third surface connection portion S3 on the upper surface of the device. It should be noted that in this embodiment, the first metal traces I1 and the second metal traces I2 may be used to transmit the same signal, but it should also be understood that the embodiments of the present application are not limited thereto, and the first metal traces I1 and the second metal traces I2 may also transmit different types of signals as described above. In this way, the present application realizes the electrical connection of the metal traces on two inclined side surfaces with different height ranges, different orientations, and different inclined angles via the third in-board connection portion S3, and can extend the multiple surface connection portions on the side surface to be connected to the devices on the upper surface of the device via the third surface connection portion S3, so that effective interconnection of devices on different layers is realized on both the inclined side surface and the upper surface.

[0092] Optionally, the inclined side surface may also have various forms. For example, the inclined side surface is formed as the outer peripheral surface of the circuit board, or is formed as the groove surface inside the circuit board, etc. The following combination Figure 9 ~ and Figure 12 will be specifically described.

[0093] Figure 9 FIG. shows a schematic diagram of a device according to the ninth embodiment of the present application.

[0094] Reference Figure 9 , in the device of this embodiment, the multi-layer circuit board may include at least two layers of first circuit boards L1. The first circuit board L1 has an inclined side surface that is inclined at a first angle F1 with respect to the vertical direction Z. In this embodiment, the inclined side surfaces of at least two layers of first circuit boards L1 may be inclined at different angles with respect to the vertical direction Z. In this way, inclined side surfaces with different slopes can be formed.

[0095] The metal traces disposed inside the multi-layer circuit board may include at least two layers of first metal traces I1. The first metal traces I1 extend horizontally to the inclined side surfaces of the first circuit board L1. In this embodiment, at least two layers of first metal traces I1 extend horizontally to the inclined side surfaces with different slopes of different first circuit boards L1.

[0096] The device of this embodiment may further include a first surface connection portion S1 extending on the inclined side surface of the first circuit board L1. The first surface connection portion S1 is located between at least two layers of first metal traces I1 in the vertical direction Z and is connected to one end of at least two layers of first metal traces I1, so as to be in electrical contact with at least two layers of first metal traces I1. In this way, at least two layers of first metal traces I1 can be electrically connected via the first surface connection portion S1. In this embodiment, the first surface connection portion S1 may extend on the inclined side surfaces with different slopes of at least two layers of first circuit boards L1, so as to be in electrical contact with at least two layers of first metal traces I1 on the inclined side surfaces with different slopes. It should be understood that Figure 9 The number of metal traces, surface connection portions, and circuit boards shown in Figure 9The changing trend of the slope of the inclined side surfaces of different first circuit boards L1 schematically shown in the figure is gradually increasing from bottom to top. The embodiments of the present application are not limited thereto. In other embodiments, the slope of the inclined side surfaces of different first circuit boards L1 may also gradually decrease from top to bottom. In an embodiment of the present application, one end of one side of the first metal trace I1 has an interface flush with the inclined side surface of the first circuit board L1. The first surface connection portion S1 is connected to at least two layers of the first metal traces I1 via the interfaces of at least two layers of the first metal traces I1. Specifically, the area of the interface at one end of one side of the first metal trace I1 is positively correlated with the first angle. That is, when the slope of the inclined side surface is larger, the area of the above-mentioned interface at one end of one side of the first metal trace can be correspondingly larger, thereby increasing the contact area between the first metal trace I1 and the first surface connection portion S1 and improving the interconnection effect. And the embodiments of the present application are not limited thereto. In another embodiment, the thickness of the first metal trace I1 may be positively correlated with the first angle of the inclined side surface of the first circuit board L1 where the first metal trace I1 is located with respect to the vertical direction Z. For example, the thicker the first metal trace I1, the larger the slope of the inclined side surface of the first circuit board L1 to which the first metal trace I1 extends (i.e., the inclination angle with respect to the vertical direction Z). In this way, the first surface connection portion S1 with a relatively larger area can be better attached to the inclined side surface, ensuring the stability of the electrical connection of at least two layers of the first metal traces I1. It should be understood that when the first metal trace I1 is thicker, the thickness of the first circuit board L1 can be correspondingly controlled to change (for example, become thicker) to ensure impedance matching.

[0097] Figure 10 FIG. shows a schematic diagram of an apparatus according to a tenth embodiment of the present application.

[0098] Reference Figure 10 , in the apparatus of this embodiment, the multi-layer circuit board may include at least two first circuit boards L1. The first circuit board L1 has an inclined side surface inclined at a first angle F1 with respect to the vertical direction Z. In this embodiment, the inclined side surfaces of at least two first circuit boards L1 may be inclined at different angles with respect to the vertical direction Z. In this way, inclined side surfaces with different slopes can be formed. And the embodiments of the present application are not limited thereto. Any number of the first circuit boards L1 among at least two first circuit boards L1 may also have inclined side surfaces facing other directions. The inclination angles of different-facing inclined side surfaces of the same first circuit board L1 with respect to the vertical direction Z may be the same or different.

[0099] The metal traces disposed inside the multi-layer circuit board may include at least two layers of first metal traces I1. The first metal traces I1 extend horizontally to the inclined side surfaces of the first circuit board L1. In this embodiment, at least two layers of first metal traces I1 extend horizontally in different directions to the inclined side surfaces with different slopes of different first circuit boards L1, and the inclined side surfaces with different slopes of different first circuit boards L1 face different directions. It should be understood that in Figure 10 the inclined side surfaces with different orientations of the same first circuit board L1 shown in may be opposite surfaces or adjacent surfaces, and the present application does not limit this.

[0100] In this embodiment, the first surface connection portion S1 may extend on the inclined side surfaces with the same orientation and different slopes of at least two layers of first circuit boards L1 and be in electrical contact with the first metal traces I1 at at least one of the inclined side surfaces. And, on the inclined side surface of the first circuit board L1 with the other orientation, another first surface connection portion S1 may also be provided, and this another first surface connection portion S1 may be in electrical contact with another part of the first metal traces I1 among at least two layers of first metal traces I1 on this inclined side surface.

[0101] The device of this embodiment may further include a first surface connection portion S1 extending on the inclined side surface of the first circuit board L1 and a third surface connection portion extending on the upper surface of the first circuit board L1. The first surface connection portions S1 extending on the inclined side surfaces with different orientations may all be formed into a continuous integral structure with the third surface connection portion S3, so as to realize the electrical connection of the first metal traces I1 at different heights and with ends at the inclined side surfaces with different orientations.

[0102] Figure 11 FIG. shows a schematic diagram of a device according to the eleventh embodiment of the present application.

[0103] Referring to Figure 11 , in the device of this embodiment, the multi-layer circuit board may include at least two layers of first circuit boards L1. The first circuit board L1 has inclined side surfaces inclined at a first angle F1 with respect to the vertical direction Z. For example, any one of at least two layers of first circuit boards L1 may have inclined side surfaces inclined at different included angles with respect to the vertical direction Z.

[0104] In this embodiment, at least two layers of first metal traces I1 extend horizontally in different directions to the inclined side surfaces with different slopes of different first circuit boards L1, and the inclined side surfaces with different slopes of different first circuit boards L1 face different directions. On this basis, in Figure 11 , at least two layers of first metal traces I1 extend respectively in different horizontal directions. For example, in Figure 11Among them, the first metal trace I1 at the lower part extends in the first horizontal direction X, and the first metal trace I1 at the upper part extends in the second horizontal direction Y.

[0105] In this embodiment, the first surface connection portion S1 can extend on the inclined side surfaces with the same orientation and different slopes of at least two layers of the first circuit board L1 (for example, the inclined side surface facing the first horizontal direction X), and is in electrical contact with the first metal trace I1 at at least one of the inclined side surfaces. Also, another first surface connection portion S1 can be provided on the inclined side surface of the first circuit board L1 in the other orientation (for example, the inclined side surface facing the second horizontal direction Y), and this another first surface connection portion S1 can be in electrical contact with another part of the first metal traces I1 among at least two layers of the first metal traces I1 on this inclined side surface. The first surface connection portions S1 on the inclined side surfaces in different orientations can be formed into an integral continuous structure, so as to be in electrical contact with the ends of the first metal traces I1 on the inclined side surfaces in different orientations, different heights, and different slopes, thereby realizing arbitrary interconnection of at least two layers of the first metal traces I1.

[0106] Figure 12 The schematic diagram of the device according to the twelfth embodiment of the present application is shown.

[0107] Reference Figure 12 , in the device of this embodiment, the multi-layer circuit board can include at least two layers of the first circuit board L1. The first circuit board L1 has an inclined side surface inclined at a first angle with respect to the vertical direction Z. For example, any one of at least two layers of the first circuit board L1 can have an inclined side surface inclined at a different included angle with respect to the vertical direction Z. In this embodiment, the inclined side surface of the device can be formed into a groove surface recessed into the board. The groove surface can include at least two inclined side surfaces facing different directions, and the inclination angles of the at least two inclined side surfaces facing different directions with respect to the vertical direction Z can be the same or different.

[0108] In this embodiment, at least two layers of the first metal traces I1 extend in the horizontal direction towards the inclined side surfaces with different slopes, different heights, and different orientations of different first circuit boards L1. And in this embodiment, the first surface connection portion S1 can extend on the inclined side surfaces with different orientations and different slopes in the groove, and is in electrical contact with the ends of at least two layers of the first metal traces I1. Based on this, the first surface connection portions S1 on the inclined side surfaces in different orientations in the groove can be formed into an integral continuous structure, so as to be in electrical contact with the ends of the first metal traces I1 on the inclined side surfaces in different orientations, different heights, and different slopes in the groove, thereby realizing arbitrary interconnection of at least two layers of the first metal traces I1.

[0109] Figure 13A flowchart showing another method of manufacturing a device according to an embodiment of the present application is presented.

[0110] As Figure 13 shown, the method of manufacturing a device in this embodiment includes operations S1310 to S1330.

[0111] In operation S1310, a multi-layer circuit board stacked in the vertical direction and metal traces in the multi-layer circuit board are formed.

[0112] In operation S1320, the side surface of the multi-layer circuit board is inclined relative to the vertical direction to form an inclined side surface of the multi-layer circuit board. Among them, the inclined side surfaces of at least two first circuit boards in the multi-layer circuit board expose the ends of at least two first metal traces.

[0113] In operation S1330, a first surface connection portion is formed on the inclined side surface of the first circuit board, so that the first surface connection portion connects the ends of at least two first metal traces.

[0114] Figure 14A A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process is shown. Figure 14B A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process after the manufacturing process shown is presented. Figure 14A A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process after the manufacturing process shown is presented. Figure 14C A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process after the manufacturing process shown is presented. Figure 14B A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process after the manufacturing process shown is presented. Figure 14D A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process after the manufacturing process shown is presented. Figure 14C A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process after the manufacturing process shown is presented. Figure 14E A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process after the manufacturing process shown is presented. Figure 14D A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process after the manufacturing process shown is presented. Figure 14F A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process after the manufacturing process shown is presented. Figure 14E A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process after the manufacturing process shown is presented. Figure 14G A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process after the manufacturing process shown is presented. Figure 14F A cross-sectional view of the device according to the thirteenth embodiment of the present application in a manufacturing process after the manufacturing process shown is presented.

[0115] Referring Figure 14A , a multi-layer circuit board stacked in the vertical direction and metal traces between the multi-layer circuit boards can be formed in the manner described above. The multi-layer first metal traces in the device are completely surrounded by the first circuit board L1, and the ends of the multi-layer first metal traces I1 in the first horizontal direction X are covered by the side surface of the first circuit board L1 that has not been inclined.

[0116] Thereafter, the side surface of the first circuit board L1 can be inclined at a first angle in the vertical direction Z to form an inclined side surface of the first circuit board L1. Refer to Figure 14A - 14B , the first circuit board L1 can be milled using a milling process at a certain angle (such as the above-mentioned first angle) so that the side surface of the first circuit board L1 is inclined, thereby exposing the ends of at least two layers of the first metal traces I1 via the inclined side surface of the first circuit board L1. In this way, the ends of the metal traces that need to be interconnected can be exposed through the milling process. After milling using the milling process, the interface of the exposed ends of at least two layers of the first metal traces I1 on the inclined side surface is flush with the inclined side surface of the first circuit board. For example, the above angle can be determined based on the thickness of at least two layers of the first circuit board and the number of layers of at least two layers of the first metal traces.

[0117] Thereafter, a first surface connection portion S1 can be formed on the inclined side surface.

[0118] Refer to Figure 14A - 14C , an initial connection layer OS can be formed on the inclined side surface to at least partially cover the inclined side surface. For example, the thickness of the initial connection layer OS can be greater than or equal to 33 microns. For example, the initial connection layer OS can be formed on the inclined side surface by electroplating a metal material. For example, the material of the initial connection layer OS can include copper, etc.

[0119] Refer to Figure 14A - 14D , an initial sacrificial layer OSS can be formed on the initial connection layer OS by electroplating a metal material. For example, the thickness of the initial sacrificial layer OSS can be 5 - 8 microns. Thereafter, the initial sacrificial layer OSS can be patterned. The material of the initial sacrificial layer OSS can be tin, and a laser can be used to pattern the initial sacrificial layer OSS to form a patterned sacrificial layer. Refer to Figure 14A - 14E , the patterned sacrificial layer SS partially covers the first portion S11 of the initial connection layer OS and exposes the second portion S12 of the initial connection layer OS. The first portion S11 is at least partially in contact with the ends of at least two layers of the first metal traces I1.

[0120] Refer to Figure 14A - 14F , the second portion S12 can be removed. For example, the second portion S12 can be removed by using alkaline etching.

[0121] Refer to Figure 14A - 14G, after removing the second part S12, the patterned sacrificial layer SS can be removed. For example, a solution such as nitric acid can be used to remove the patterned sacrificial layer SS. The first part S11 remaining on the side surface is used as the first surface connection portion S1. In this way, the position where the first surface connection portion S1 is formed on the side surface can be controlled by patterning, so as to realize arbitrary interconnection of multi-layer metal traces. It should be understood that this is only an example of the first circuit board, the first metal trace and the first surface connection portion. The methods described above are also applicable to other circuit boards, metal traces and surface connection portions in this application, and will not be elaborated here.

[0122] Based on this, in this application, an initial connection layer is first formed on the inclined surface of the circuit board, and then an initial sacrificial layer is formed. Then, based on the different volatilization temperatures of the initial connection layer and the initial sacrificial layer, a patterned sacrificial layer used as a negative image is ablated on the inclined surface by using a laser. For example, taking the sacrificial layer as a tin layer and the connection layer as a copper layer as an example, the volatilization temperature of tin is only 232 degrees, and the melting point of copper is about 1086 degrees. Then, the first part of the connection layer covered by the patterned sacrificial layer is used as a positive image. On this basis, the initial connection layer is etched, and the patterned sacrificial layer can protect the first part under the positive image, so that an interconnection line can be formed.

[0123] In Figure 2B - 2D In the illustrated embodiment, during the process of forming a multi-layer HDI, multiple repeated operations such as lamination, drilling, electroplating, and patterning are required, and the operations are relatively cumbersome. And the method of this embodiment forms a surface connection layer on the inclined side surface through the process described above, avoiding repeated processing using processes such as lamination, drilling, electroplating, and patterning, greatly improving the manufacturing efficiency of HDI, reducing the resources consumed by manufacturing high-order HDI devices, and improving the yield of the manufactured high-order HDI devices.

[0124] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the above-mentioned module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than marked in the accompanying drawings. For example, two consecutively represented blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, as well as the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0125] Those skilled in the art will appreciate that the features described in the various embodiments of the present application can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present application. In particular, without departing from the spirit and teachings of the present application, the features described in the various embodiments of the present application can be combined and / or combined in various ways. All such combinations and / or combinations fall within the scope of the present application.

[0126] The embodiments of the present application have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application. Although the embodiments have been described separately above, this does not mean that the measures in the respective embodiments cannot be used advantageously in combination. Without departing from the scope of the present application, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present application.

Claims

1. An apparatus including a circuit board, characterized in that, Comprising: A multi-layer circuit board, stacked in the vertical direction and having an inclined side surface inclined with respect to the vertical direction; the circuit board has metal traces; at least two first metal traces of at least two first circuit boards in the multi-layer circuit board extend horizontally to the inclined side surface of the at least two first circuit boards; A first surface connection portion, located on the inclined side surface of the first circuit board and connecting the ends of the at least two first metal traces.

2. The device according to claim 1, characterized in that, The multi-layer circuit board further includes at least two second circuit boards; at least two second metal traces of the at least two second circuit boards extend horizontally to the inclined side surface of the at least two second circuit boards; the inclined side surface of the first circuit board and the inclined side surface of the second circuit board have different inclination angles; The device further includes a second surface connection portion, located on the inclined side surface of the second circuit board and connecting the ends of the at least two second metal traces.

3. The device according to claim 2, characterized in that, The at least two first metal traces and the at least two second metal traces are respectively located in different regions of the multi-layer circuit board; the metal traces in different regions are used to transmit different types of signals.

4. The device according to claim 2, characterized in that, The end of the first metal trace has an interface flush with the inclined side surface of the first circuit board; the first surface connection portion is connected to the at least two first metal traces via the interface of the at least two first metal traces; The end of the second metal trace has an interface flush with the inclined side surface of the second circuit board; the second surface connection portion is connected to the at least two second metal traces via the interface of the at least two second metal traces; Wherein, the area of the interface of the first metal trace is different from the area of the interface of the second metal trace.

5. The device according to claim 4, characterized in that, The inclined side surface of the first circuit board is inclined at a first angle with respect to the vertical direction, and the inclined side surface of the second circuit board is inclined at a second angle with respect to the vertical direction; When the first angle is greater than the second angle, the area of the interface at the end of the first metal trace is greater than the area of the interface at the end of the second metal trace; When the first angle is less than the second angle, the area of the interface at the end of the first metal trace is less than the area of the interface at the end of the second metal trace.

6. The device according to claim 5, characterized in that, The first angle is greater than 0° and less than 90°; the second angle is greater than 0° and less than 90°.

7. The device according to any one of claims 2 to 6, characterized in that The inclined side surface of the first circuit board includes an inclined side surface facing a first direction and an inclined side surface facing a second direction different from the first direction.

8. The device according to any one of claims 2 to 6, characterized in that, It further includes a third surface connection portion, extending on the upper surface of the uppermost circuit board in the multi-layer circuit board and connected to at least one of the first surface connection portion and the second surface connection portion.

9. The device according to any one of claims 1 to 6, characterized in that, The thickness of the multi-layer circuit board decreases successively in the vertical direction.

10. The device according to claim 9, characterized in that, The multi-layer circuit board further includes at least two third circuit boards; each of the at least two third circuit boards includes vias filled with a conductive material; the third metal traces of the at least two third circuit boards are electrically connected via the conductive material in the vias of the at least two third circuit boards; Among them, the inner sidewalls of the vias of the at least two layers of the third circuit board are inclined relative to the vertical direction; the inclination angle of the inner sidewalls of the vias of the upper third circuit board among the at least two layers of the third circuit board is smaller than that of the inner sidewalls of the vias of the lower third circuit board, and the thickness of the upper third circuit board is thinner than that of the lower third circuit board.

11. The device according to claim 10, characterized in that, The central top of the conductive material in the via of the upper third circuit board has a first concave distance relative to the top of the inner sidewall of the via of the upper third circuit board; the central top of the conductive material in the via of the lower third circuit board has a second concave distance relative to the top of the inner sidewall of the via of the lower third circuit board; Among them, the first concave distance is smaller than the second concave distance.

12. The device according to claim 11, characterized in that, The first concave distance is 0 to 1.5 mil; the second concave distance is 0 to 1.5 mil.

13. The device according to any one of claims 1 to 6, characterized in that The at least two layers of the first metal traces are not electrically connected through the conductive material filled in the via.

14. The device according to any one of claims 1 to 6, characterized in that, The first metal trace and the first surface connection part are made of the same material.

15. The device according to any one of claims 1 to 6, characterized in that, The inclined side surface is formed as the outer peripheral surface of the circuit board or as the groove surface inside the circuit board.

16. A method of manufacturing any one of the devices as claimed in claims 1 to 15, characterized in that, Including: Forming a multi-layer circuit board stacked in the vertical direction and metal traces in the multi-layer circuit board; Making the side surface of the multi-layer circuit board inclined relative to the vertical direction to form an inclined side surface of the multi-layer circuit board; among them, the inclined side surfaces of at least two layers of the first circuit boards in the multi-layer circuit board expose the ends of at least two layers of the first metal traces; On the inclined side surface of the first circuit board, forming a first surface connection part so that the first surface connection part connects the ends of the at least two layers of the first metal traces.

17. The method according to claim 16, wherein The interface of the exposed ends of the at least two layers of the first metal traces is flush with the inclined side surface of the first circuit board.

18. The method according to claim 17, wherein Before making the side surface of the multi-layer circuit board inclined, the ends of the at least two layers of the first metal traces are covered by the side surfaces of the at least two layers of the first circuit boards; Making the side surface of the multi-layer circuit board inclined relative to the vertical direction to form an inclined side surface of the multi-layer circuit board includes: Milling the at least two layers of the first circuit boards at a certain angle by using a milling cutter process so that the side surfaces of the at least two layers of the first circuit boards are inclined to form the inclined side surfaces of the at least two layers of the first circuit boards, thereby exposing the ends of the at least two layers of the first metal traces through the inclined side surfaces of the at least two layers of the first circuit boards.

19. The method according to claim 18, wherein The method further includes: Determining the angle based on the thickness of the at least two layers of the first circuit boards and the number of layers of the at least two layers of the first metal traces.

20. The method according to any one of claims 16 to 19, characterized in that, Forming a first surface connection part on the inclined side surface of the first circuit board includes: Forming an initial connection layer on the inclined side surface of the first circuit board to at least partially cover the inclined side surface of the first circuit board; Form a patterned sacrificial layer on the initial connection layer, wherein the patterned sacrificial layer covers a first portion of the initial connection layer and exposes a second portion of the initial connection layer, and wherein the first portion is at least partially in contact with the ends of the at least two layers of first metal traces; Remove the second portion of the initial connection layer exposed by the sacrificial layer, and remove the patterned sacrificial layer after removing the second portion; the first portion of the initial connection layer remains on the inclined side surface of the first circuit board and serves as the first surface connection portion.

21. The method according to claim 20, characterized in that, Forming a patterned sacrificial layer on the initial connection layer includes: Form an initial sacrificial layer on the initial connection layer by electroplating a metal material; Pattern the initial sacrificial layer to form the patterned sacrificial layer.

22. The method according to claim 21, wherein Pattern the initial sacrificial layer to form the patterned sacrificial layer, including: Use a laser to pattern the initial sacrificial layer to form the patterned sacrificial layer.

23. The method according to claim 20, wherein Form an initial connection layer on the inclined side surface of the first circuit board, including: Form the initial connection layer on the inclined side surface of the first circuit board by electroplating a metal material.

24. The method according to claim 20, wherein Removing the second portion of the initial connection layer exposed by the sacrificial layer includes: Remove the second portion by means of alkaline etching.

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