Printed circuit board

Abstract

The present disclosure relates to a printed circuit board including: an insulating layer; a through hole penetrating the insulating layer from an upper surface to a lower surface of the insulating layer and having an inclined wall surface; the metal ball is arranged in the through hole and is in contact with the inclined wall surface; and the metal via hole fills the through hole and surrounds the metal ball.

Description

[0001] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0116899 filed on September 4, 2023 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. Technical Field

[0002] The present disclosure relates to a printed circuit board. Background Art

[0003] Packaging technology continues to develop, and specifically, attempts continue to be made to use silicon or glass to move away from the use of organic materials in traditional substrate manufacturing methods. Here, glass is known to have better anti-warping properties than conventional organic materials and has better planarization properties, which can be advantageous for reducing the line width and space of traces. However, in the manufacture of current substrates, it may be difficult to form through vias in a thick glass core. For example, a seed layer may be required for plating in a via hole, but because the glass surface is smooth and the via hole has a high aspect ratio, it may be difficult to form the seed layer. In addition, when the seed layer is formed using a sputtering process, etc., it may take a lot of time and cost to form a seed layer with the desired thickness. Summary of the invention

[0004] An aspect of the present disclosure is to provide a printed circuit board that can improve the quality of a substrate by suppressing the formation of voids or seams even when fill plating is performed on a through hole having a high aspect ratio, such as a through hole formed in a glass core.

[0005] Another aspect of the present disclosure is to provide a printed circuit board that can minimize time and cost by simplifying a sputtering process even when a seed layer is formed in a via having a high aspect ratio, such as a via formed in a glass core.

[0006] One of the various solutions proposed by the present disclosure is to form a through hole with an inclined wall in an insulating layer as a glass core, insert and place a metal ball in the through hole, then form a seed layer in the through hole by a sputtering process, and also perform fill plating to form a metal via surrounding the metal ball.

[0007] According to one aspect of the present disclosure, a printed circuit board may include: an insulating layer; a through hole penetrating the insulating layer from an upper surface to a lower surface of the insulating layer and having an inclined wall surface; a metal ball disposed in the through hole and in contact with the inclined wall surface; and a metal via filling the through hole and surrounding the metal ball.

[0008] According to another aspect of the present disclosure, a printed circuit board may include: an insulating layer having a through hole; a metal ball arranged in the through hole; a first seed metal layer arranged on the upper surface of the insulating layer and extending from the upper area of ​​the through hole to the wall surface of the through hole to cover a portion of the metal ball; a second seed metal layer arranged on the lower surface of the insulating layer and extending from the lower area of ​​the through hole to the wall surface of the through hole to cover another portion of the metal ball; a first metal layer arranged on the first seed metal layer and filling a portion of the through hole located in the upper area of ​​the through hole; and a second metal layer arranged on the second seed metal layer and filling another portion of the through hole located in the lower area of ​​the through hole.

[0009] One effect of the present disclosure is to provide a printed circuit board that can improve the quality of a substrate by suppressing the formation of voids or seams even when fill plating is performed on a through hole having a high aspect ratio, such as a through hole formed in a glass core.

[0010] Another effect of the present disclosure is to provide a printed circuit board that can minimize time and cost by simplifying a sputtering process even when a seed layer is formed in a through hole having a high aspect ratio, such as a through hole formed in a glass core. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The above and other aspects, features and advantages of the present disclosure will be more clearly understood through the following detailed description in conjunction with the accompanying drawings, in which:

[0012] Figure 1 is a block diagram schematically illustrating an example of an electronic device system;

[0013] Figure 2 is a perspective view schematically showing an example of an electronic device;

[0014] Figure 3 is a cross-sectional view schematically showing an example of a printed circuit board;

[0015] 4A to 4F is a schematic diagram showing the manufacturing Figure 3 A process cross-sectional view of an example of a printed circuit board;

[0016] Figure 5 is a cross-sectional view schematically showing another example of a printed circuit board;

[0017] 6A to 6F is a schematic diagram showing the manufacturing Figure 5 A process cross-sectional view of an example of a printed circuit board; and

[0018] 7A to 7C are cross-sectional views schematically showing various examples of metal balls. DETAILED DESCRIPTION

[0019] Hereinafter, the present disclosure will be described with reference to the accompanying drawings. In the accompanying drawings, the shapes and sizes of elements may be exaggerated or reduced for clearer description.

[0020] Electronic Devices

[0021] Figure 1 is a block diagram schematically illustrating an example of an electronic device system.

[0022] Reference Figure 1 , the electronic device 1000 may house a mainboard 1010 therein. Chip-related components 1020, network-related components 1030, and other components 1040 are physically and / or electrically connected to the mainboard 1010. These components are connected to other electronic components to be described below via various signal lines 1090.

[0023] The chip-related components 1020 may include: memory chips, such as volatile memory (e.g., DRAM), non-volatile memory (e.g., ROM, flash memory), etc.; application processor chips, such as central processing units (e.g., CPU), graphics processors (e.g., GPU), digital signal processors, cryptographic processors, microprocessors, microcontrollers, etc.; and logic chips, such as analog-to-digital converters (ADCs), application-specific integrated circuits (ASICs), etc. However, the chip-related components 1020 are not limited thereto, and may also include other types of chip-related components. In addition, the chip-related components 1020 may be combined with each other. The chip-related components 1020 may be in the form of a package including the aforementioned chips or electronic components.

[0024] The network-related components 1030 may include components compatible with or communicating using protocols such as Wireless Fidelity (Wi-Fi) (such as IEEE 802.11 series), Worldwide Interoperability for Microwave Access (WiMAX) (IEEE802.16 series, etc.), IEEE 802.20, Long Term Evolution (LTE), Evolution Data Optimization (Ev-DO), HSPA+, HSDPA+, HSUPA+, EDGE, GSM, GPS, GPRS, CDMA, TDMA, DECT, Bluetooth, 3G protocols, 4G protocols, and 5G protocols, as well as any other wireless standards or protocols and wired standards or protocols specified after the above protocols. However, the network-related components 1030 are not limited thereto, and may include components compatible with or communicating using any of a variety of other wireless standards or protocols or wired standards or protocols. In addition, the network-related components 1030 may be combined with the chip-related components 1020.

[0025] Other components 1040 may include high frequency inductors, ferrite inductors, power inductors, ferrite beads, low temperature co-fired ceramic (LTCC) components, electromagnetic interference (EMI) filters, multilayer ceramic capacitors (MLCC), etc. However, other components 1040 are not limited thereto, and may also include passive components in the form of chip components for various other purposes. In addition, other components 1040 may be combined with chip-related components 1020 and / or network-related components 1030.

[0026] Depending on the type of the electronic device 1000, the electronic device 1000 may include other electronic components that are physically and / or electrically connected to the mainboard 1010 or that are not physically and / or electrically connected to the mainboard 1010. These other electronic components may include, for example, a camera 1050, an antenna 1060, a display 1070, a battery 1080. However, these other electronic components are not limited thereto, but may be an audio codec, a video codec, a power amplifier, a compass, an accelerometer, a gyroscope, a speaker, a mass storage device (e.g., a hard disk drive), a compact disk (CD) drive, a digital versatile disk (DVD) drive, etc. In addition, depending on the type of the electronic device 1000, the electronic device 1000 may also include other electronic components for various purposes.

[0027] The electronic device 1000 may be a smart phone, a personal digital assistant, a digital video camera, a digital camera, a network system, a computer, a monitor, a tablet PC, a laptop PC, a netbook PC, a television, a video game console, a smart watch, or an automotive component. However, the electronic device 1000 is not limited thereto, but may be any other electronic device capable of processing data.

[0028] Figure 2 is a perspective view schematically showing an example of an electronic device.

[0029] Reference Figure 2 , the electronic device may be, for example, a smart phone 1100. The mainboard 1110 may be housed in the smart phone 1100, and various components 1120 may be physically and / or electrically connected to the mainboard 1110. In addition, other components (such as a camera module 1130 and / or a speaker 1140) that are physically and / or electrically connected to the mainboard 1110 or that are not physically and / or electrically connected to the mainboard 1110 may be housed in the smart phone 1100. Some of the components 1120 may be the above-mentioned chip-related components (e.g., component packages 1121), but the present disclosure is not limited thereto. The component package 1121 may be in the form of a printed circuit board on which an electronic component (including an active component and / or a passive component) is surface mounted. Alternatively, the component package 1121 may be in the form of a printed circuit board in which an electronic component (including an active component and / or a passive component) is embedded. On the other hand, the electronic device need not be limited to the smart phone 1100, and may also be other electronic devices as described above.

[0030] Printed Circuit Board

[0031] Figure 3 is a cross-sectional view schematically showing an example of a printed circuit board.

[0032] Reference Figure 3 , a printed circuit board 100A according to an example embodiment may include: an insulating layer 110; a through hole H1 penetrating the insulating layer 110 from the upper surface to the lower surface of the insulating layer 110 and having an inclined wall surface; a metal ball 150 disposed in the through hole H1; a metal via 140 filling the through hole H1 and surrounding the metal ball 150; a first metal wiring 120 disposed on the upper surface of the insulating layer 110 and connected to the upper end of the metal via 140; and a second metal wiring 130 disposed on the lower surface of the insulating layer 110 and connected to the lower end of the metal via 140. The through hole H1 may be tapered so that the width of its upper end is wider than the width of its lower end in cross section. The metal ball 150 may be disposed in the through hole H1 through the inclined wall surface of the through hole H1. The diameter of the metal ball 150 may be greater than the minimum width of the through hole H1 so that the metal ball 150 fits inside the through hole H1. The through hole H1 may have an upper region R1 and a lower region R2 separated by the metal ball 150. The through hole H1 may have a tapered shape, and thus, since the metal ball 150 is disposed at an appropriate position, the areas of the upper region R1 and the lower region R2 may be different from each other in cross section.

[0033] In addition, the metal via 140 may include: a first seed metal layer m1 disposed on the inclined wall surface in the upper region R1 and covering the upper exposed portion of the metal ball 150; a second seed metal layer m2 disposed on the inclined wall surface in the lower region R2 and covering the lower exposed portion of the metal ball 150; a first metal layer M1 disposed on the first seed metal layer m1 in the upper region R1 to fill a portion of the through hole H1; and a second metal layer M2 disposed on the second seed metal layer m2 in the lower region R2 to fill another portion of the through hole H1. The first metal wiring 120 and the second metal wiring 130 may be connected to each other through the metal via 140 and the metal ball 150. In addition, the first metal wiring 120 may include a third seed metal layer m3 disposed on the upper surface of the insulating layer 110 and a third metal layer M3 disposed on the third seed metal layer m3, and the second metal wiring 130 may include a fourth seed metal layer m4 disposed on the lower surface of the insulating layer 110 and a fourth metal layer M4 disposed on the fourth seed metal layer m4. According to an embodiment, the first seed metal layer m1 and the third seed metal layer m3 may be formed by the same process so that they may be integrated with each other, and the first metal layer M1 and the third metal layer M3 may also be formed by the same process and integrated. Similarly, the second seed metal layer m2 and the fourth seed metal layer m4 may be formed by the same process and integrated, and the second metal layer M2 and the fourth metal layer M4 may be formed by the same process and integrated. In addition, the metal ball 150 may preferably include a copper ball, and in this regard, each of the first seed metal layer m1 and the second seed metal layer m2 and the first metal layer M1 and the second metal layer M2 may preferably include copper (Cu).

[0034] In addition, the insulating layer 110 may include a glass layer. The glass layer may include glass that is an amorphous solid. The glass may include, for example, pure silicon dioxide (about 100% SiO2), soda-lime glass, borosilicate glass, and aluminosilicate glass. However, the glass is not limited thereto, and alternative glass materials (such as fluorine glass, phosphate glass, chalcogenide glass, etc.) may also be used as materials. Additives may also be included to form glass with specific physical properties. These additives may include at least one selected from the group consisting of magnesium, calcium, manganese, aluminum, lead, boron, iron, chromium, potassium, sulfur, antimony, calcium carbonate (e.g., lime), sodium carbonate (e.g., soda), and combinations thereof. The glass layer may be a layer other than an organic insulating material (e.g., copper clad laminate (CCL), prepreg (PPG), etc.) including glass fiber (e.g., glass fabric of glass cloth). For example, the glass layer may be a flat glass.

[0035] As described above, in the printed circuit board 100A according to the example embodiment, in the case where the metal via 140 having a high aspect ratio is formed in the insulating layer 110 (such as a glass layer) having a considerable thickness, the metal ball 150 may be pre-inserted into the through hole H1, and then assembled in the through hole H1 and contact the inclined wall surface of the through hole H1, followed by a plating process. For example, after the metal ball 150 is inserted, the first seed metal layer m1 (and the third seed metal layer m3) and the second seed metal layer m2 (and the fourth seed metal layer m4) may be formed in two directions respectively using sputtering, which may easily form the seed layer and simplify the sputtering process. Therefore, the metal ball 150 may be fixed so that it does not detach. In addition, after the metal ball 150 is inserted, the first metal layer M1 (and the third metal layer M3) and the second metal layer M2 (and the fourth metal layer M4) may be formed in two directions respectively using filling plating, which may effectively suppress the occurrence of voids or seams in the through hole H1. Therefore, the quality of the substrate may be improved.

[0036] In addition, the printed circuit board 100A according to the example embodiment may be applied to any layer of a multilayer circuit board. For example, it may be applied to a core layer of a multilayer circuit board, and in this case, a buildup process may be performed on one or both sides of the printed circuit board 100A. The multilayer circuit board may be used as a thin film chip board (FCB), a ball grid array (BGA), an interposer substrate, and a package substrate. However, the present disclosure is not limited thereto, and the multilayer circuit board may be applied to other various types of substrates.

[0037] Hereinafter, components of a printed circuit board 100A according to example embodiments will be described in more detail with reference to the accompanying drawings.

[0038] The insulating layer 110 may include an insulating material. The insulating material may include glass, but the present disclosure is not limited thereto, and the insulating material may include various other materials such as ceramics, silicon (Si) and / or silicone resin, and organic insulating materials. The insulating material may preferably include glass, and thus the insulating layer 110 may be flat glass, but is not limited thereto.

[0039] Each of the first metal wiring 120 and the second metal wiring 130 may include a metal material. The metal material may include at least one selected from the group consisting of copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), and alloys thereof. For example, each of the third seed metal layer m3 and the third metal layer M3 of the first metal wiring 120 and the fourth seed metal layer m4 and the fourth metal layer M4 of the second metal wiring 130 may include the above-mentioned metal material, and may preferably include copper (Cu), but the present disclosure is not limited thereto. Each of the first metal wiring 120 and the second metal wiring 130 may perform various functions according to its design. For example, the first metal wiring 120 and the second metal wiring 130 may include a signal pattern, a power pattern, or a ground pattern. Each of these patterns may have various shapes such as a line, a plane, and a pad. Each of the first metal wiring 120 and the second metal wiring 130 may include an electroless plating layer (e.g., a chemical copper plating layer) and an electrolytic plating layer (e.g., an electrolytic copper plating layer), but the present disclosure is not limited thereto. Each of the first metal wiring 120 and the second metal wiring 130 may include a sputtering layer instead of an electroless plating layer (e.g., a chemical copper plating layer), and if necessary, each of the first metal wiring 120 and the second metal wiring 130 may include both an electroless plating layer (e.g., a chemical copper plating layer) and a sputtering layer.

[0040] The metal via 140 may include a metal material. The metal material may include at least one selected from the group consisting of copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), and alloys thereof. For example, each of the first seed metal layer m1 and the second seed metal layer m2 and the first metal layer M1 and the second metal layer M2 of the metal via 140 may include the above-mentioned metal material, and may preferably include copper (Cu), but the present disclosure is not limited thereto. The metal via 140 may perform various functions according to its design. For example, the metal via 140 may include a ground via, a power via, and a signal via. The metal via 140 may include an electroless plating layer (e.g., a chemical copper plating layer) and an electrolytic plating layer (e.g., an electrolytic copper plating layer), but the present disclosure is not limited thereto. A sputtering layer may be formed instead of the electroless plating layer (e.g., a chemical copper plating layer), and if necessary, the metal via 140 may include both the electroless plating layer (e.g., a chemical copper plating layer) and the sputtering layer.

[0041] The metal ball 150 may include a metal material. The metal material may include at least one selected from the group consisting of copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), and alloys thereof. For example, the metal ball 150 may include a copper ball, but is not limited thereto. The metal ball 150 may also include a nickel (Ni) layer and / or a solder layer formed on the surface of the copper ball, as described below.

[0042] 4A to 4F is a schematic diagram showing the manufacturing Figure 3 FIG. 1 is a process cross-sectional view of an example of a printed circuit board.

[0043] Referring to the accompanying drawings, Figure 4A In the process, an insulating layer 110 is prepared. As described above, the insulating layer 110 may be a glass layer (such as a flat glass). Figure 4B In the embodiment, a through hole H1 is formed in the insulating layer 110. The through hole H1 may be formed in a tapered shape by etching after setting a mask on the upper surface of the insulating layer 110 (such as a glass layer), but the present disclosure is not limited thereto. For example, other chemical methods or mechanical methods may be used to form the through hole H1. A plurality of through holes H1 may be formed, and each through hole H1 may be the same or different. Next, in Figure 4C In the embodiment, the metal ball 150 is inserted into the through hole H1. The metal ball 150 may be placed in the through hole H1 and contact the inclined wall surface of the tapered through hole H1. Figure 4D In the embodiment, a third seed metal layer m3 and a first seed metal layer m1 are formed on the upper surface of the insulating layer 110 and the upper region R1 of the through hole H1, respectively. The first seed metal layer m1 and the third seed metal layer m3 may be formed by a sputtering process, but the present disclosure is not limited thereto. Next, Figure 4E In the embodiment, a fourth seed metal layer m4 and a second seed metal layer m2 are formed on the lower surface of the insulating layer 110 and the lower region R2 of the through hole H1, respectively. The second seed metal layer m2 and the fourth seed metal layer m4 may be formed by a sputtering process, but the present disclosure is not limited thereto. Next, Figure 4F In the embodiment, a first metal layer M1 and a third metal layer M3 are formed on the upper surface of the insulating layer 110 and the upper region R1 of the through hole H1, and a second metal layer M2 and a fourth metal layer M4 are formed on the lower surface of the insulating layer 110 and the lower region R2 of the through hole H1. Each of the first to fourth metal layers M1 to M4 may have a dry film resist patterned to form an opening for plating, and then may be formed by fill plating or the like based on the first to fourth seed metal layers m1 to m4, but the present disclosure is not limited thereto. Thereafter, when unnecessary portions of the first to fourth seed metal layers m1 to m4 are removed by seed layer etching or the like, a first metal wiring 120 and a second metal wiring 130 and a metal via 140 may be formed. The printed circuit board 100A according to the above-described example embodiment may be formed by a series of processes, and other contents are substantially the same as those described above, so a repeated description thereof will be omitted.

[0044] Figure 5 is a cross-sectional view schematically showing another example of a printed circuit board.

[0045] Reference Figure 5, the printed circuit board 100B according to another example embodiment may be configured such that the through hole H2 may be tapered toward both the upper and lower sides of the insulating layer 110, so that the width of each of the upper and lower portions of the through hole H2 is wider in cross section than the width of the portion between the upper and lower portions of the through hole H2. For example, the through hole H2 may have an hourglass shape. The metal ball 150 may be inserted and disposed on the upper side of the through hole H2, but the present disclosure is not limited thereto, and the metal ball 150 may be inserted and disposed on the lower side of the through hole H2. Other details are substantially the same as the above details, and thus repeated descriptions thereof are omitted.

[0046] 6A to 6F is a schematic diagram showing the manufacturing Figure 5 FIG. 1 is a process cross-sectional view of an example of a printed circuit board.

[0047] Referring to the drawings, the printed circuit board 100B according to the above-described another exemplary embodiment may be formed by 4A to 4F The through hole H2 may be formed by a process substantially the same as the process of the through hole H2. For example, the through hole H2 may include a first tapered hole formed by a first etching after a first mask is set on an upper surface of the insulating layer 110 such as a glass layer, and further include a second tapered hole formed by a second etching after a second mask is set on a lower surface of the insulating layer 110 such as a glass layer, so that the through hole H2 may be formed in a tapered shape on both sides. However, the present disclosure is not limited thereto, and the through hole H2 may be formed by, for example, other chemical methods or mechanical methods.

[0048] 7A to 7C are cross-sectional views schematically showing various examples of metal balls.

[0049] Referring to the accompanying drawings, Fig. 7A As shown in FIG. 1 , the metal ball 150A may include a substantially circular copper ball 151 and a nickel (Ni) plating layer 152 formed on the surface of the copper ball 151. Figure 7B As shown in , the metal ball 150B may include a substantially circular copper ball 151, a nickel (Ni) plating layer 152 formed on the surface of the copper ball 151, and a solder plating layer 153 further formed on the surface of the nickel (Ni) plating layer 152 and having a thickness greater than that of the nickel (Ni) plating layer 152. Figure 7C As shown in FIG. 1 , the metal ball 150C may have only the copper ball 151. In this case, the metal balls 150A, 150B, and 150C may have various forms and may be applied as the metal balls 150 to the printed circuit board 100A according to the above example embodiment or the printed circuit board 100B according to another example embodiment.

[0050] In the present disclosure, the expression "covering" may include a case of covering at least a portion as well as a case of covering the entirety, and may also include a case of direct covering as well as a case of indirect covering. Furthermore, the expression "filling" may include not only a case of complete filling but also a case of approximately complete filling, and may include, for example, a case where some holes or gaps exist. Furthermore, the expression "surrounding" may include not only a case of complete surrounding but also a case of approximately complete surrounding.

[0051] In the present disclosure, the meaning of a cross section may refer to the cross-sectional shape when an object is cut vertically, or the shape when the object is observed in a side view. In addition, the meaning of a plane may refer to the plane shape when an object is cut horizontally, or the plane shape when the object is observed in a top view or a bottom view.

[0052] In the present disclosure, thickness, width, length and depth can be measured by a scanning microscope or an optical microscope based on a cross section obtained by polishing or cutting, respectively. The cut section can be a vertical section or a horizontal section, and each numerical value can be measured based on the desired cut section. When the value is not constant, the value can be determined as the average value of the values ​​measured at any five points. The width of the upper end and / or lower end of the through hole can be measured on a cross section obtained by cutting in the thickness direction along the central axis of the through hole in the substrate. The depth of the through hole can be measured by the following method: on a cross section obtained by cutting in the thickness direction along the central axis of the through hole in the substrate, measure the distance from the upper end to the lower end of each through hole.

[0053] In the present disclosure, "lower" in the lower side, lower part, and lower surface is used to refer to the downward direction relative to the cross section of the drawing, and "upper" in the upper side, upper part, and upper surface is used to refer to the opposite direction thereof. However, this is to define the direction for the convenience of explanation, the scope of the present disclosure is not particularly limited to the description of such direction, and the concepts of upper part and lower part may be changed at any time.

[0054] In the present disclosure, the meaning of connection includes not only direct connection but also the concept of indirect connection through an adhesive layer or the like. In addition, the meaning of electrical connection is a concept including both physical connection and non-physical connection. In addition, expressions such as "first" and "second" are used to distinguish one component from another component and do not limit the order and / or importance of the components. In some cases, a first component may be referred to as a second component, or similarly, a second component may be referred to as a first component without departing from the scope of the rights.

[0055] The expression "exemplary embodiment" used in this disclosure does not mean the same embodiment, and is provided to illustrate different unique features. However, the exemplary embodiments presented above do not exclude being implemented in combination with features of other exemplary embodiments. For example, even if matters described in a particular exemplary embodiment are not described in other exemplary embodiments, they may be understood as descriptions related to other exemplary embodiments unless there are contrary or contradictory descriptions of matters in other exemplary embodiments.

[0056] The terms used in the present disclosure are only used to describe example embodiments and are not intended to limit the present disclosure. In this case, unless they are clearly indicated as different in the context, the singular expression includes the plural expression.

[0057] While example embodiments have been shown and described above, it will be readily apparent to those skilled in the art that modifications and variations may be made without departing from the scope of the present disclosure as defined by the appended claims.

Claims

1. A printed circuit board, comprising: Insulation layer; a through hole penetrating the insulating layer from an upper surface to a lower surface of the insulating layer and having an inclined wall surface; a metal ball disposed in the through hole and in contact with the inclined wall surface; as well as A metal via fills the through hole and surrounds the metal ball.

2. The printed circuit board according to claim 1, wherein: The through hole is divided into an upper area and a lower area by the metal ball, and The cross-sectional area of ​​the upper region is different from the cross-sectional area of ​​the lower region.

3. The printed circuit board according to claim 2, wherein: The metal via comprises: a first seed metal layer disposed on the inclined wall surface in the upper region and also covering an upper portion of the metal ball; a second seed metal layer disposed on the inclined wall surface in the lower region and also covering a lower portion of the metal ball; a first metal layer disposed on the first seed metal layer to fill a portion of the through hole located in the upper region; and A second metal layer is disposed on the second seed metal layer to fill another portion of the through hole located in the lower region.

4. The printed circuit board according to claim 3, further comprising: A first metal wiring and a second metal wiring are disposed on the upper surface and the lower surface of the insulating layer, respectively, and are connected to each other through the metal via and the metal ball.

5. The printed circuit board according to claim 4, wherein: The first metal wiring includes a third seed metal layer disposed on the upper surface of the insulating layer and a third metal layer disposed on the third seed metal layer, and The second metal wiring includes a fourth seed metal layer disposed on the lower surface of the insulating layer and a fourth metal layer disposed on the fourth seed metal layer.

6. The printed circuit board according to claim 5, wherein: Each of the first seed metal layer, the second seed metal layer, the third seed metal layer, and the fourth seed metal layer includes copper, and Each of the first metal layer, the second metal layer, the third metal layer, and the fourth metal layer includes copper.

7. The printed circuit board according to claim 1, wherein: The through hole has a tapered shape such that, in cross section, a width of an upper end of the through hole is wider than a width of a lower end of the through hole.

8. The printed circuit board according to claim 1, wherein: In cross section, a width of each of the upper and lower ends of the through hole is wider than a width of a portion between the upper and lower ends of the through hole.

9. The printed circuit board according to claim 1, wherein: The insulating layer includes a glass layer.

10. The printed circuit board according to any one of claims 1 to 9, wherein: The metal ball includes a copper ball.

11. The printed circuit board according to claim 10, wherein: The metal ball further includes a nickel layer covering a surface of the copper ball.

12. The printed circuit board according to claim 11, wherein The metal ball further includes a solder layer covering a surface of the nickel layer.

13. A printed circuit board, comprising: an insulating layer having a through hole; A metal ball is disposed in the through hole; a first seed metal layer disposed on an upper surface of the insulating layer, a wall surface of the through hole connected to the upper surface of the insulating layer, and an upper portion of the metal ball; a second seed metal layer disposed on the lower surface of the insulating layer, a wall surface of the through hole connected to the lower surface of the insulating layer, and a lower portion of the metal ball; a first metal layer disposed on the first seed metal layer and filling a portion of the through hole located in an upper region of the through hole; as well as A second metal layer is disposed on the second seed metal layer and fills another portion of the through hole located in a lower region of the through hole.

14. The printed circuit board according to claim 13, wherein: At least a portion of the wall surface of the through hole has an inclined shape, and The metal ball is in contact with the inclined portion of the wall surface of the through hole.

15. The printed circuit board according to claim 13 or 14, in, The insulating layer comprises a glass layer, The metal ball comprises a copper ball, Each of the first seed metal layer and the second seed metal layer includes copper, and each of the first metal layer and the second metal layer includes copper.

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