Printed circuit board

Abstract

The invention relates to a printed circuit board. The printed circuit board includes: a first insulating layer including a groove portion provided on an upper side of the first insulating layer; and a first wiring layer having an embedded portion embedded in the groove portion and a protruding portion protruding onto the first insulating layer. A width of a lower end portion of the protruding portion of the first wiring layer is narrower than a width of an upper end portion.

Description

[0001] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0138204 filed on October 17, 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] Multi-chip packages, which include memory chips (such as high bandwidth memory (HBM), processor chips (such as central processing units (CPUs), graphics processing units (GPUs), and logic chips (such as application-specific integrated circuits (ASICs) and field-programmable gate arrays (FPGAs)), are being used to process the exponentially growing data caused by recent advances in artificial intelligence (AI) technology. In detail, the number of CPU cores and GPU cores in server products has increased rapidly, and a finer chip metal pillar pitch is required. Therefore, research is continuing on a structure that reduces the pitch of a circuit pattern of a printed circuit board in response to the demand for higher density to increase yield. Summary of the invention

[0004] An aspect of the present disclosure is to provide a printed circuit board in which a wiring layer having a fine pitch can be implemented.

[0005] Another aspect of the present disclosure is to provide a printed circuit board in which a portion of a wiring layer can be embedded and another portion of the wiring layer can be protruded.

[0006] Another aspect of the present disclosure is to provide a printed circuit board having improved reliability.

[0007] According to one aspect of the present disclosure, a printed circuit board is provided, the printed circuit board comprising: a first insulating layer, comprising a groove portion provided on an upper side of the first insulating layer; and a first wiring layer, comprising an embedded portion embedded in the groove portion of the first insulating layer and a protruding portion protruding onto the first insulating layer. The width of the lower end portion of the protruding portion of the first wiring layer is narrower than the width of the upper end portion.

[0008] According to another aspect of the present disclosure, a printed circuit board is provided, the printed circuit board comprising: a first insulating layer, comprising a groove portion provided on an upper side of the first insulating layer; a first wiring layer, having an embedded portion embedded in the groove portion of the first insulating layer and a protruding portion protruding onto the first insulating layer, and a second wiring layer, embedded below the first insulating layer and spaced apart from the first wiring layer. The wiring density of the first wiring layer is greater than the wiring density of the second wiring layer.

[0009] According to another aspect of the present disclosure, there is provided a printed circuit board, comprising: an insulating layer including a groove portion provided on an upper side of the insulating layer; and a wiring layer having an embedded portion embedded in the groove portion of the insulating layer and a protruding portion protruding onto the insulating layer. The wiring layer comprises: a first metal layer provided on an inner wall of the groove portion of the insulating layer; a second metal layer provided on the first metal layer; and a third metal layer provided on the second metal layer. Each of the first metal layer, the second metal layer and the third metal layer comprises a portion provided in the groove portion of the insulating layer and a portion protruding onto the insulating layer. The second metal layer comprises a metal different from the metal of the first metal layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other aspects, features and advantages of the present disclosure will be more clearly understood through the following detailed description taken in conjunction with the accompanying drawings, in which: Figure 1 is a block diagram schematically illustrating an example of an electronic device system; Figure 2 is a perspective view schematically showing an example of an electronic device; Figure 3 is a cross-sectional view schematically showing a printed circuit board according to an example; Figure 4 is a cross-sectional view schematically showing a printed circuit board according to another example; Figure 5 is a cross-sectional view schematically showing a printed circuit board according to another example; Figure 6 is a cross-sectional view schematically showing a printed circuit board according to another example; Figure 7 and Figure 8 is a cross-sectional view schematically illustrating a method for manufacturing a printed circuit board according to an example; Fig. 9 is a cross-sectional view schematically showing a part of a method for manufacturing a printed circuit board according to another example; and Fig.10 and Fig.11 is a cross-sectional view schematically illustrating a method of manufacturing a printed circuit board according to another example. DETAILED DESCRIPTION

[0011] Hereinafter, the present disclosure will be described with reference to the accompanying drawings. For clearer description, the shapes and sizes of elements in the drawings may be exaggerated or reduced.

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

[0013] Reference Figure 1 , the electronic device 1000 may house a mainboard 1010 therein. Chip-related components 1020, network-related components 1030, other components 1040, etc. may be physically or electrically connected to the mainboard 1010. These electronic components may be connected to other electronic components to be described below via various signal lines 1090.

[0014] The chip-related components 1020 may include: memory chips, such as volatile memory (e.g., dynamic random access memory (DRAM)), non-volatile memory (e.g., read-only memory (ROM), flash memory), etc.; application processor chips, such as central processing units (e.g., central processing units (CPUs)), graphics processors (e.g., graphics processing units (GPUs)), 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, but may also include other types of chip-related components. In addition, the chip-related components 1020 may also be combined with each other. The chip-related components 1020 may be in the form of a package including the above-mentioned chips or electronic components.

[0015] The network-related components 1030 may include components that are compatible with or operate according to protocols such as: Wireless Fidelity (Wi-Fi) (Institute of Electrical and Electronics Engineers (IEEE) 802.11 series, etc.), Worldwide Interoperability for Microwave Access (WiMAX) (IEEE 802.16 series, etc.), IEEE 802.20, Long Term Evolution (LTE), Evolution-Data Optimized (Ev-DO), High Speed ​​Packet Access + (HSPA+), High Speed ​​Downlink Packet Access + (HSDPA+), High Speed ​​Uplink Packet Access + (HSUPA+), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), Global Positioning System (GPS), General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Enhanced Digital Cordless Telecommunications (DECT), Bluetooth, third generation mobile communication technology (3G) protocols, fourth generation mobile communication technology (4G) protocols, and fifth generation mobile communication technology (5G) protocols, as well as any other wireless protocols and wired protocols specified after the above protocols. However, the network-related component 1030 is not limited thereto, but may also include components compatible with or operating in accordance with various other wireless standards or protocols or wired standards or protocols. In addition, the network-related component 1030 may be combined with the chip-related component 1020 described above.

[0016] The 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, the other components 1040 are not limited thereto, and may also include passive components in the form of chip components for various other purposes, etc. In addition, the other components 1040 may also be combined with the above-mentioned chip-related components 1020 and / or network-related components 1030.

[0017] Depending on the type of the electronic device 1000, the electronic device 1000 may include other electronic components that are physically or electrically connected to the mainboard 1010 or that are not physically or electrically connected to the mainboard 1010. These other electronic components may include, for example, a camera 1050, an antenna 1060, a display 1070, and a battery 1080, etc. However, these other electronic components are not limited thereto, and may also be an audio codec, a video codec, a power amplifier, a compass, an accelerometer, a gyroscope, a speaker, a mass storage unit (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.

[0018] The electronic device 1000 may be a smart phone, a personal digital assistant (PDA), 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, an automobile component, etc. However, the electronic device 1000 is not limited thereto but may be any other electronic device capable of processing data.

[0019] Figure 2 is a schematic perspective view showing an example of an electronic device.

[0020] Reference Figure 2, the electronic device may be, for example, a smart phone 1100. A mainboard 1110 is housed inside the smart phone 1100, and various components 1120 are physically or electrically connected to the mainboard 1110. In addition, other electronic components (such as a camera module 1130 and / or a speaker 1140) that are physically or electrically connected to the mainboard 1110 or that are not physically 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, for example, a component package 1121, but are 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.

[0021] Printed Circuit Board Figure 3 is a cross-sectional view schematically illustrating a printed circuit board according to an example.

[0022] Reference Figure 3 According to the example, the printed circuit board includes: a first insulating layer 110 including a groove portion; and a first wiring layer 120 having an embedded portion embedded in the groove portion and a protruding portion protruding onto the first insulating layer 110. The first wiring layer 120 may include: a first metal layer 121 disposed on the inner wall of the groove portion and extending along a portion of the upper surface of the first insulating layer 110; and a second metal layer 122 disposed on the first metal layer 121, and the protruding portion of the first wiring layer 120 may have a tapered shape in which the width of the lower end portion is narrower than the width of the upper end portion. In addition, as Figure 3 As shown in the figure, the width of a portion of the first metal layer 121 adjacent to the upper surface of the first insulating layer 110 is narrower than the width of the upper surface of the first metal layer 121, and the width of a portion of the second metal layer 122 adjacent to the upper surface of the first insulating layer 110 is narrower than the width of the upper surface of the second metal layer 122.

[0023] The first insulating layer 110 may include an insulating material. The insulating material may include a thermosetting resin (such as an epoxy resin), a thermoplastic resin (such as polyimide), or a material prepared by impregnating a core material (such as glass fiber (such as glass fabric, for example, glass cloth)) with an inorganic filler, an organic filler into a thermosetting resin or a thermoplastic resin. The insulating material may be a photosensitive material and / or a non-photosensitive material. For example, the insulating material of the first insulating layer 110 may be an insulating material such as a prepreg (PPG) or a copper-clad resin (RCC), but is not limited thereto, and may be an Ajinomoto deposited film (ABF), a photosensitive dielectric (PID), FR-4, bismaleimide triazine (BT), etc. However, the present disclosure is not limited thereto, and other polymer materials having excellent rigidity may be used if necessary.

[0024] The first insulating layer 110 may have a groove portion on the upper side. The groove portion is a portion formed by removing at least a portion of the upper side of the first insulating layer 110, and may penetrate a portion of the first insulating layer 110. The groove portion penetrates only a portion of the first insulating layer 110 and does not penetrate the entire first insulating layer 110 so that the upper surface and the lower surface of the first insulating layer are not connected. The groove portion may be formed by etching a portion of the first insulating layer 110 from the upper side of the first insulating layer 110, but the present disclosure is not limited thereto. The groove portion may be formed by using any method that can remove a portion of the first insulating layer 110 to form a groove portion penetrating a portion thereof on one side of the first insulating layer 110 without limitation.

[0025] The first wiring layer 120 may include a first metal layer 121 and a second metal layer 122 disposed on the first metal layer 121. The first wiring layer 120 may include a metal material. The metal material may be copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), lead (Pb), titanium (Ti), or an alloy thereof. Preferably, the first wiring layer 120 may include copper (Cu), but the present disclosure is not limited thereto, and the first metal layer 121 and the second metal layer 122 may include different metal materials.

[0026] The first wiring layer 120 may perform various functions according to the design. For example, the first wiring layer 120 may include a signal pattern, a power pattern, a ground pattern, etc., but the present disclosure is not limited thereto, and may be used as a pad on which electronic components and chips may be mounted. Each of these patterns may have various forms such as lines, surfaces, pads, etc. A portion of the first wiring layer 120 may be embedded in the first insulating layer 110, and another portion of the first wiring layer 120 may protrude onto the first insulating layer 110. In this case, the embedded portion of the first wiring layer 120 does not completely penetrate the first insulating layer 110, and is formed to only partially penetrate the first insulating layer 110. Specifically, the first wiring layer 120 may be formed by filling a groove portion that penetrates a portion of the first insulating layer 110, but the present disclosure is not limited thereto. Another portion of the first wiring layer 120 may be disposed on the first insulating layer 110 to form a protrusion that protrudes beyond the first insulating layer 110. The width of the embedded portion of the first wiring layer 120 may be narrower than the width of the protrusion of the first wiring layer 120. This is a result of forming a groove portion having a width smaller than the wiring width in the protruding portion of the first wiring layer 120 .

[0027] The first metal layer 121 may include one metal material selected from the group of metal materials of the first wiring layer 120 described above. Preferably, the first metal layer 121 may include copper (Cu), but the present disclosure is not limited thereto, and in some cases, the first metal layer 121 may include a plurality of metal layers. In this case, when the first metal layer 121 includes a plurality of metal layers, the plurality of metal layers may include different metal materials. The first metal layer 121 may be used as a seed for forming the second metal layer 122. If necessary, the first metal layer 121 may include an electroless plating layer (e.g., a chemical copper plating layer), a sputtering layer, or both.

[0028] The first metal layer 121 may be disposed on the inner wall of the groove portion and extend to a portion of the upper side of the first insulating layer 110. The first metal layer 121 may form a portion of the embedded portion of the first wiring layer 120 and a portion of the protruding portion of the first wiring layer 120. The first metal layer 121 may be conformally disposed along the groove portion formed in the first insulating layer 110. That is, the first metal layer 121 may be formed along the inner wall of the groove portion formed in the first insulating layer 110, and may be disposed to extend to the upper surface of the first insulating layer 110.

[0029] The second metal layer 122 may include one metal material selected from the group of metal materials of the first wiring layer 120 described above. The second metal layer 122 may include a metal material substantially the same as the metal material of the first metal layer 121. For example, preferably, the second metal layer 122 may include copper (Cu), but the present disclosure is not limited thereto. The second metal layer 122 may include an electrolytic plating layer (e.g., an electrolytic copper plating layer), and may further include other components required for electroplating if necessary. The second metal layer 122 may be formed by performing electroplating using the first metal layer 121 as a seed, but the present disclosure is not limited thereto.

[0030] The second metal layer 122 may be disposed on the first metal layer 121. The second metal layer 122 may form another portion of the embedded portion of the first wiring layer 120, and may also form another portion of the protruding portion of the first wiring layer 120. That is, a portion of the second metal layer 122 may be embedded in the first insulating layer 110, and another portion of the second metal layer 122 may protrude onto the first insulating layer 110. Since the width of the protruding portion of the first wiring layer 120 may be wider than the width of the embedded portion of the first wiring layer 120, the width of the portion of the second metal layer 122 forming the protruding portion may be wider than the width of the portion of the second metal layer 122 forming the embedded portion. This is related to the width of the protruding portion and the width of the embedded portion of the first wiring layer 120, and since the first metal layer 121 may have a specific thickness as a seed for the second metal layer 122, the width of the second metal layer 122 may have the above-mentioned difference.

[0031] At least a portion of the side surface of the protruding portion of the first wiring layer 120 may be an inclined surface. This may mean that at least a portion of the side surface of the first metal layer 121 forming the protruding portion of the first wiring layer 120 or at least a portion of the side surface of the second metal layer 122 forming the protruding portion of the first wiring layer 120 may be an inclined surface, but the present disclosure is not limited thereto, and may also mean that at least a portion of the side surface of the first metal layer 121 forming the protruding portion of the first wiring layer 120 and at least a portion of the side surface of the second metal layer 122 forming the protruding portion of the first wiring layer 120 may be an inclined surface. Furthermore, the present disclosure is not limited thereto, and the inclined surface of the first metal layer 121 may extend from the inclined surface of the second metal layer 122, so that the inclined surface of the first metal layer 121 and the inclined surface of the second metal layer 122 may be integrated. The fact that the inclined surface of the first metal layer 121 and the inclined surface of the second metal layer 122 can be integrated may indicate that the inclination angle formed by the inclined surface of the first metal layer 121 and the upper surface of the first insulating layer 110 is substantially the same as the inclination angle formed by the virtual extended surface of the inclined surface of the second metal layer 122 and the upper surface of the first insulating layer 110.

[0032] The side surface of the first metal layer 121 forming the protrusion of the first wiring layer 120 may be an inclined surface. Since the first metal layer 121 is used as a seed for forming the second metal layer 122, a portion of the first metal layer 121 may be removed in an operation of removing a portion of the seed during the manufacturing operation, and in this case, the side surface of the first metal layer 121 may be formed as an inclined surface. In other words, the side surface of the first metal layer 121 formed as an inclined surface may be formed in an operation of removing a portion of the seed, and may be formed when the operation of removing the seed is performed by an etching method, but the present disclosure is not limited thereto. In addition, for example, the side surface of the first metal layer 121 may have a tapered shape so that the width of the first metal layer 121 becomes narrower toward the first insulating layer 110. Here, the side surface of the first metal layer 121 may refer to the side surface of a region of the first metal layer 121 disposed on the upper surface of the first insulating layer 110. That is, the side surface of the first metal layer 121 may have a downwardly tapered shape. This may occur when the operation of removing a portion of the seed is performed isotropically, and may occur because the lower portion of the first metal layer 121 is removed more than the upper portion of the first metal layer 121. In this case, the width of the first metal layer 121 may represent: with respect to the first metal layer 121 forming the protrusion of the first wiring layer 120, the distance between one side surface of the first metal layer 121 and the other side surface of the first metal layer 121 opposite to the one side surface. In other words, the distance may represent the horizontal distance between the side surfaces of the first metal layer 121 forming the protrusion of the first wiring layer 120.

[0033] Since the first metal layer 121 and the second metal layer 122 may include substantially the same metal material, in the operation of removing a portion of the seed during the manufacturing operation, not only a portion of the first metal layer 121 may be removed, but also a portion of the second metal layer 122 may be removed together. Since a portion of the second metal layer 122 may be removed, a portion of the side surface of the second metal layer 122 may also be formed as an inclined surface. In addition, since a portion of the first metal layer 121 and a portion of the second metal layer 122 may be removed at the same time, the inclined surface of the first metal layer 121 may extend from the inclined surface of the second metal layer 122. That is, the inclined surface of the first metal layer 121 and the inclined surface of the second metal layer 122 may be integrally formed. In addition, since a portion of the second metal layer 122 may be removed in the operation of removing a portion of the seed, the inclined surface may be formed only in a portion of the second metal layer 122 adjacent to the first metal layer 121. However, the present disclosure is not limited thereto, and the inclined surface may be formed from the upper surface of the second metal layer 122, or the inclined surface may not be formed in the second metal layer 122 and the inclined surface may be formed only in the first metal layer 121. Since at least a portion of the side surface of the first metal layer 121 and / or at least a portion of the side surface of the second metal layer 122 may be an inclined surface, the width of the lower end of the protrusion of the first wiring layer 120 may be formed narrower than the width of the upper end.

[0034] In addition, the shape of the side surface of the first metal layer 121 and the shape of the side surface of the second metal layer 122 are not limited to Figure 3 The shape of the inclined surface shown in , further, may include any surface shape without limitation as long as it is a shape of the first wiring layer 120 that can appear in the operation of removing the plating seed. For example, the first wiring layer 120 may have a structure in which the entirety of the first metal layer 121 forming the protruding portion of the first wiring layer 120 is removed, and may have a shape in which the width of the protruding portion of the first wiring layer 120 is narrower than the width of the embedded portion of the first wiring layer 120 (for example, an hourglass shape).

[0035] Since the printed circuit board according to the example includes an embedded portion in which a portion of the first wiring layer 120 is embedded in the first insulating layer 110, even if at least a portion of the side surface of the first metal layer 121 and / or the side surface of the second metal layer 122 is an inclined surface, the first wiring layer 120 will not be peeled off from the first insulating layer 110. When the printed circuit board includes fine wiring, undercutting may occur in the operation of removing the seed, causing a defect in which the wiring is peeled off from the insulating layer and falls off. However, in the printed circuit board according to the example, since the contact area between the first insulating layer 110 and the first wiring layer 120 can be further increased by embedding the first wiring layer 120 in a portion of the first insulating layer 110, even if undercutting occurs in the operation of removing the seed, the adhesion between the first insulating layer 110 and the first wiring layer 120 can be ensured. That is, since the first wiring layer 120 is formed to fill the groove portion formed in the first insulating layer 110, the contact area between the first wiring layer 120 and the first insulating layer 110 increases by the area corresponding to the side wall of the groove portion (i.e., the increased contact area between the first wiring layer 120 and the first insulating layer 110 is equal to the area of ​​the side wall of the groove portion). In addition, since the area where the undercut of the first wiring layer 120 occurs when the seed is removed is not only in close contact with the first insulating layer 110 but also connected to the embedded portion of the first wiring layer 120, the first wiring layer 120 can be prevented from being separated from the first insulating layer 110. Since the area where the undercut occurs in the first wiring layer 120 is formed integrally with the embedded portion of the first wiring layer 120, even if the undercut occurs, no defect will occur due to the bonding force between the embedded portion of the first wiring layer 120 and the protruding portion (including the metal material having the same composition). That is, when a portion of the first wiring layer 120 is not embedded in the first insulating layer 110 , the connection can only be maintained by the adhesion force between the first wiring layer 120 and the first insulating layer 110 , so embedding a portion of the first wiring layer 120 in the first insulating layer 110 may be more advantageous.

[0036] The printed circuit board according to the example may further include a second wiring layer 130 disposed under the first insulating layer 110. The fact that the second wiring layer 130 is disposed under the first insulating layer 110 may mean that the second wiring layer is embedded in the lower surface of the first insulating layer 110, such as Figure 3 . However, the present disclosure is not limited thereto, and the second wiring layer 130 may be provided on the lower surface of the first insulating layer 110 and have a protruding structure. The fact that the second wiring layer 130 is embedded in the lower surface of the first insulating layer 110 may mean that the remaining surface of the second wiring layer 130 except the lower surface is covered by the first insulating layer 110, and the lower surface of the second wiring layer 130 is not covered by the first insulating layer 110 but is exposed through the lower surface of the first insulating layer 110.

[0037] In addition, the second wiring layer 130 is spaced apart from the first wiring layer 120. The fact that the second wiring layer 130 is spaced apart from the first wiring layer 120 may mean that the embedded portion of the first wiring layer 120 does not directly contact the second wiring layer 130. In other words, this may mean that the embedded portion of the first wiring layer 120 is a component different from the via that performs interlayer connection and can be distinguished from the via. This is because the embedded portion of the first wiring layer 120 does not penetrate the entirety of the first insulating layer 110, but only penetrates a portion of the first insulating layer 110.

[0038] The second wiring layer 130 may include a metal material. The metal material may be copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), lead (Pb), titanium (Ti) or an alloy thereof. Preferably, the second wiring layer 130 may include copper (Cu), but the present disclosure is not limited thereto. The second wiring layer 130 may be formed using any one of a semi-additive process (SAP), a modified semi-additive process (MSAP), a hole sealing (TT) method and a subtractive method, but is not limited thereto. The second wiring layer 130 may include an electroless plating layer (e.g., a chemical copper plating layer) as a seed layer and an electrolytic plating layer (e.g., an electrolytic copper plating layer) as a plating layer, but is not limited thereto. A sputtering layer may be formed instead of the chemical copper plating layer as the electroless plating layer. If necessary, the second wiring layer 130 may also include a copper foil. The second wiring layer 130 may perform various functions according to the design. For example, the second wiring layer 130 may include a signal pattern, a power pattern, a ground pattern, etc., but is not limited thereto, and may be used as a pad for mounting electronic components, chips, etc., or as a pad for connecting to another board. Each of these patterns may have various forms such as a line, a plane, a pad, etc.

[0039] The first wiring layer 120 may have a greater wiring density than the second wiring layer 130. That is, the first wiring layer 120 may include wirings that are finer than the wirings of the second wiring layer 130. The fact that the wiring density is higher is a relative concept, and may mean, for example, that the average pitch of the wirings included in the first wiring layer 120 may be smaller than the average pitch of the wirings included in the second wiring layer 130. The pitch may be measured by photographing a cross section cut along the stacking direction of the printed circuit board using a scanning electron microscope, and the average pitch may be the average value of the pitches between the wirings measured at five arbitrary points. That is, the wirings included in the first wiring layer 120 may be high-density fine wirings having a line width / spacing (L / S) that is smaller than the line width / spacing (L / S) of the wirings included in the second wiring layer 130. As a non-limiting example, the line width / spacing of the wirings included in the first wiring layer 120 may be approximately 2m / 2m, but the present disclosure is not limited thereto. Since a portion of the first wiring layer 120 is embedded in the first insulating layer 110, wirings that are finer than the wirings of the second wiring layer 130 may be implemented in the first wiring layer 120. The wiring density of the first wiring layer 120 may be greater than the wiring density of the second wiring layer 130. Figure 3 , the thickness of the first wiring layer 120 and the thickness of the second wiring layer 130 are shown to be similar, but the present disclosure is not limited thereto, and since the first wiring layer 120 can be formed to be finer than the second wiring layer 130, the thickness of the first wiring layer 120 can be thinner than the thickness of the second wiring layer 130.

[0040] The printed circuit board according to the example is not limited to Figure 3 The components shown in Figure 3 Only a portion of the printed circuit board is shown, and other components may also be included. For example, other components such as an insulating layer, a circuit, and an interlayer via may also be included below the first insulating layer 110. The insulating layer, the circuit, and the interlayer via may also be further included above the first insulating layer 110. In other words, additional components that can be used by those skilled in the art or those skilled in the relevant technical field may also be included.

[0041] Figure 4 is a cross-sectional view schematically illustrating a printed circuit board according to another example.

[0042] Reference Figure 4, the first wiring layer 120 of the printed circuit board according to another example may further include a third metal layer 123 disposed under the first metal layer 121. Similar to the first metal layer 121, a portion of the third metal layer 123 may be embedded in the first insulating layer 110, and another portion of the third metal layer 123 may be disposed on the first insulating layer 110. The third metal layer 123 may be conformally disposed along a groove portion formed in the first insulating layer 110. That is, the third metal layer 123 may be formed along an inner wall of a groove portion formed in the first insulating layer 110, and may be disposed to extend to an upper surface of the first insulating layer 110.

[0043] The third metal layer 123 may include one material selected from the group of metal materials of the first wiring layer 120 described above. The third metal layer 123 may include a metal material different from the metal material of the first metal layer 121. In addition, the third metal layer 123 may include a metal material different from the metal material of the second metal layer 122. Preferably, the third metal layer 123 may include titanium (Ti), but the present disclosure is not limited thereto, and in some cases, the third metal layer 123 may include a plurality of metal layers. In this case, when the third metal layer 123 includes a plurality of metal layers, the plurality of metal layers may include different metal materials. The third metal layer 123 may be formed before forming the first metal layer 121. The third metal layer 123 may be disposed between the first metal layer 121 and the first insulating layer 110 to ensure adhesion of the first metal layer 121. The third metal layer 123 may include a sputtering layer, but the present disclosure is not limited thereto. Since the third metal layer 123 may include a sputtering layer, the first metal layer 121 may also include a sputtering layer, but the present disclosure is not limited thereto.

[0044] At least a portion of the side surface of the third metal layer 123 may be an inclined surface. At least a portion of the side surface of the third metal layer 123 forming the protrusion of the first wiring layer 120 may be an inclined surface. The side surface of the third metal layer 123 may have the same meaning as the side surface of the first metal layer 121. That is, the side surface of the third metal layer 123 may refer to the side surface of the region of the third metal layer 123 disposed on the upper surface of the first insulating layer 110. Since the third metal layer 123 may be conformally disposed on the first insulating layer 110 before forming the first metal layer 121, an operation of removing a portion of the third metal layer 123 may be included in the operation of completing the first wiring layer 120. When the operation of removing a portion of the third metal layer 123 is performed by an etching method, the side surface of the third metal layer 123 may be formed as an inclined surface in the operation of removing a portion of the third metal layer 123. In this case, since the operation of removing a portion of the third metal layer 123 may be performed after the operation of removing a portion of the first metal layer 121, the inclined surface of the third metal layer 123 may be formed along the inclined surface of the first metal layer 121. This may be a result of the etchant penetrating along the inclined surface of the first metal layer 121 when the isotropic etching is performed.

[0045] exist Figure 4 , the inclined surface of the first metal layer 121 and the inclined surface of the third metal layer 123 are shown as being integrated, but the present disclosure is not necessarily limited thereto, and the inclined surface of the first metal layer 121 and the inclined surface of the third metal layer 123 may have various shapes. Since the third metal layer 123 may include a metal material different from the metal materials of the first metal layer 121 and the second metal layer 122, the third metal layer 123 may not react in the operation of removing a portion of the first metal layer 121, and the first metal layer 121 and the second metal layer 122 may not react in the operation of removing a portion of the third metal layer 123, so that the third metal layer 123 may have various shapes. For example, the inclined surface of the first metal layer 121 and the inclined surface of the third metal layer 123 may have different inclination angles, but the present disclosure is not limited thereto, and may also have a shape in which the side surface of the third metal layer 123 may protrude more than the first metal layer 121 at the contact surface between the third metal layer 123 and the first metal layer 121.

[0046] In addition, since it can be combined with Figure 3 The same configuration as that of the printed circuit board according to the example shown in FIG. 1 (except for the third metal layer 123) is applied to Figure 4 A printed circuit board according to another example is shown in FIG. 8 , and thus a repeated description thereof will be omitted.

[0047] Figure 5 is a cross-sectional view schematically illustrating a printed circuit board according to another example.

[0048] Reference Figure 5 In a printed circuit board according to another example, the first wiring layer 120 may protrude above the first insulating layer 110 without extending on the upper surface of the first insulating layer 110. That is, a portion of the first wiring layer 120 may form an embedded portion embedded in the first insulating layer 110, and another portion of the first wiring layer 120 may form a protruding portion protruding above the first insulating layer 110. In this case, the upper surface of the first wiring layer 120 may be set higher than the upper surface of the first insulating layer 110.

[0049] In a printed circuit board according to another example, since the third metal layer 123 is formed without removing the dry film formed on the first insulating layer 110, the third metal layer 123 may be formed along the wall surface of the opening formed in the dry film. Since the dry film is removed in a subsequent operation, the third metal layer 123 may be disposed on the first insulating layer 110 according to the shape of the opening formed in the dry film. That is, since the third metal layer 123 and the first metal layer 121 are directly formed without removing the dry film for forming the groove portion, the first wiring layer 120 may not extend on the upper surface of the first insulating layer 110. Therefore, the protrusion of the first wiring layer 120 may have a constant width. In addition, the width of the lower portion of the protrusion of the first wiring layer 120 may be substantially the same as the width of the upper portion of the embedded portion of the first wiring layer 120.

[0050] Can be used with Figure 3 The printed circuit board according to the example shown in Figure 4 The same configuration (except for the configuration and shape of the first wiring layer 120) as the configuration of the printed circuit board according to another example shown in Figure 5 A printed circuit board according to another example is shown in FIG. 8 , and thus a repeated description thereof will be omitted.

[0051] Figure 6 is a cross-sectional view schematically illustrating a printed circuit board according to another example.

[0052] Reference Figure 6 In a printed circuit board according to another example, the first wiring layer 120 may have a region in which at least a portion of the first metal layer 121 and at least a portion of the second metal layer 122 are recessed.

[0053] In addition, the first wiring layer 120 may have a step formed between the third metal layer 123 and the first metal layer 121 and / or between the third metal layer 123 and the second metal layer 122 .

[0054] This can be achieved by including a seed layer 140 (see FIG. 1 ) in each of the first metal layer 121 and the second metal layer 122. Fig.10 and Fig.11), specifically, this may occur when each of the first metal layer 121, the second metal layer 122, and the seed layer 140 includes copper (Cu). In the operation of removing the seed layer 140, a portion of the first metal layer 121 and a portion of the second metal layer 122 including a metal material substantially the same as the metal material of the seed layer 140 may be removed, respectively. The operation of removing the seed layer 140 will be described later in the method for manufacturing a printed circuit board. In addition, in Figure 6 In the embodiment, the concave region is shown as having a flat surface, but the present disclosure is not limited thereto, and the surface of the concave region may be uneven. Alternatively, the concave region may have a concave shape such as a pit at the center, or conversely, may have a convex shape at the center, and the shape of the concave region may be unlimited.

[0055] Because it can be used with Figure 3 The printed circuit board according to the example shown in Figure 4 A printed circuit board according to another example shown in Figure 5 The same configuration (except for the configuration and shape of the first wiring layer 120) as the configuration of the printed circuit board according to another example shown in Figure 6 A printed circuit board according to another example is shown in FIG. 8 , and thus a repeated description thereof will be omitted.

[0056] Method for manufacturing printed circuit board Figure 7 and Figure 8 is a cross-sectional view schematically illustrating a method of manufacturing a printed circuit board according to an example.

[0057] The method for manufacturing a printed circuit board according to an example may include forming a groove portion 300 penetrating a portion of a first insulating layer 110 and forming a first wiring layer 120 including an embedded portion filling the groove portion 300 and a protruding portion protruding onto the first insulating layer 110. In this case, forming the first wiring layer 120 may include forming a first metal layer 121 along the groove portion 300 and an upper surface of the first insulating layer 110 and forming a second metal layer 122 on the first metal layer 121, and may include removing a portion of the first metal layer 121. In the operation of removing a portion of the first metal layer 121, a width of a lower end portion of the protruding portion of the first wiring layer 120 may be formed to be narrower than a width of an upper end portion of the protruding portion of the first wiring layer 120.

[0058] Reference Figure 7, a method for manufacturing a printed circuit board according to an example may include forming a dry film 201 on a first insulating layer 110. Forming the dry film 201 may include stacking dry films 201′ and patterning the dry film 201′ through exposure and development processes. An opening may be formed in the dry film 201, and a groove portion 300 corresponding to the opening may be formed in the first insulating layer 110. The dry film 201 may be any known dry film, and any material having a reactivity different from that of the first insulating layer 110 may be used in an operation of removing a portion of the first insulating layer 110 without limitation. In addition, in Figure 7 , an operation of forming a dry film 201 including a photosensitive insulating material and exposing and developing the dry film 201 is shown, but the embodiment is not limited thereto. In the operation of forming the groove portion 300 located in a portion of the first insulating layer 110, any material that can be used as a mask or a resist can be used without limitation, and materials and processing methods that can be used by those skilled in the art can be used.

[0059] In this case, the second wiring layer 130 may be embedded under the first insulating layer 110. More specifically, the method of manufacturing a printed circuit board according to an example may be performed after forming the first insulating layer 110 on the second wiring layer 130. As described above, in the printed circuit board according to the example, other components of the printed circuit board may be further included under the first insulating layer 110.

[0060] After forming the dry film 201 on the first insulating layer 110, the groove portion 300 penetrating a portion of the first insulating layer 110 may be formed. As described above, in the printed circuit board according to the example, the groove portion 300 may be a region in which the embedded portion of the first wiring layer 120 is formed. The groove portion 300 does not completely penetrate the first insulating layer 110. Since the groove portion 300 does not completely penetrate the first insulating layer 110, the second wiring layer 130 is not exposed by the groove portion 300, and then even if the first wiring layer 120 is formed to fill the groove portion 300, the first wiring layer 120 and the second wiring layer 130 may be kept spaced apart from each other. That is, the groove portion 300 penetrating a portion of the first insulating layer 110 may be different from a via hole that performs interlayer connection. The groove portion 300 may be formed by etching the first insulating layer 110, and the width and depth of the groove portion 300 may be set by the opening formed in the dry film 201. In other words, the dry film 201 may correspond to a mask or plating resist for forming the groove portion 300.

[0061] After forming the groove portion 300, the dry film 201 may be removed. The dry film 201 may be removed using any method that can be used by those skilled in the art.

[0062] Reference Figure 8, a first metal layer 121 may be formed on the first insulating layer 110. The first metal layer 121 may be used as a seed for forming a second metal layer 122 to be described later, and the first metal layer 121 may be formed by performing electroless plating, and in some cases, the first metal layer 121 may also be formed by sputtering or the like. The first metal layer 121 may be formed along the sidewall of the groove portion 300, and the first metal layer 121 may be formed to extend to the upper surface of the first insulating layer 110. The method of forming the first metal layer 121 may be a method having excellent step coverage. Since the thickness of the first metal layer 121 may be thin, the first metal layer 121 may not be formed to completely fill the groove portion 300, but may be conformally formed according to the outer shape of the groove portion 300.

[0063] Thereafter, a dry film 202′ may be provided and the dry film 202′ may be exposed and developed to form the dry film 202. The dry film 202 may include an opening, and the opening may be a region for forming the second metal layer 122. The opening of the dry film 202 may be formed to correspond to the opening of the first metal layer 121. The dry film 202 may include the same material as that of the previous dry film 201, but the present disclosure is not limited thereto, and as long as the dry film 202 can be used as a plating resist or mask for forming the second metal layer 122 to be described later, it can be used without limitation. The dry film 202 may be formed using any method that can be used by those skilled in the art.

[0064] Thereafter, the second metal layer 122 may be formed. The second metal layer 122 may be formed by performing electroplating using the first metal layer 121 as a seed, but the present disclosure is not limited thereto.

[0065] Thereafter, the dry film 202 may be removed. Any method available to those skilled in the art may be used to remove the dry film 202. In the operation of removing the dry film 202, the first metal layer 121 and the second metal layer 122 may not be deformed.

[0066] Thereafter, a portion of the first metal layer 121 may be removed to complete the first wiring layer 120. Since the first metal layer 121 is used as a seed, the first metal layer 121 enables the adjacent other first wiring layers (not shown) to perform necessary functions without short-circuiting by removing the unnecessary portion of the first metal layer 121 after forming the second metal layer 122. The operation of removing a portion of the first metal layer 121 may be performed using an etching method. More specifically, the operation may be performed using flash etching, but the present disclosure is not limited thereto. The operation of removing a portion of the first metal layer 121 is performed to remove the unnecessary portion of the seed, and any method that can be used by those skilled in the art may be used.

[0067] In this case, undercutting may occur in at least a portion of the first wiring layer 120. The occurrence of undercutting in at least a portion of the first wiring layer 120 may mean that a portion of the first metal layer 121 disposed below the second metal layer 122 may be removed, and a portion of the second metal layer 122 may also be removed together. Since the first wiring layer 120 having the embedded portion embedded in the first insulating layer 110 is formed in the printed circuit board according to the example, even if undercutting occurs in the operation of removing a portion of the first metal layer 121, a defect in which the first wiring layer 120 is peeled off from the first insulating layer 110 does not occur.

[0068] In addition, as described above, the method of manufacturing a printed circuit board according to the example is not limited to Figure 7 and Figure 8 As described above, in the assembly of the printed circuit board according to the example, other components may be further included on the lower surface of the first insulating layer 110. The method of manufacturing a printed circuit board according to the example may further include an operation of forming other components on the first insulating layer 110 after completing the first wiring layer 120.

[0069] Fig. 9 is a cross-sectional view schematically illustrating a portion of a method of manufacturing a printed circuit board according to another example.

[0070] According to another example, a method for manufacturing a printed circuit board may include: Figure 7 and Figure 8 As in the method of manufacturing a printed circuit board according to an example shown in , the groove portion 300 is formed on the upper side of the first insulating layer 110. A method of manufacturing a printed circuit board according to another example will be described focusing on an operation of forming the third metal layer 123.

[0071] Reference Fig. 9 , an operation of forming the third metal layer 123 and an operation of forming the first metal layer 121 may be performed. The operation of forming the third metal layer 123 may be performed before the operation of forming the first metal layer 121. The operation of forming the third metal layer 123 may be performed by sputtering, but the present disclosure is not limited thereto. In this case, the operation of forming the first metal layer 121 may also be performed by sputtering. When the operation of forming the third metal layer 123 and the operation of forming the first metal layer 121 are performed by the same method, the operation of forming the first metal layer 121 may be performed immediately after the operation of forming the third metal layer 123. The third metal layer 123 may be a means of ensuring adhesion between the first insulating layer 110 and the first metal layer 121, and the third metal layer 123 may include a metal material different from that of the first metal layer 121.

[0072] Thereafter, the dry film 202 may be formed as a plating resist, the second metal layer 122 may be formed, and the dry film 202 may be removed.

[0073] Thereafter, an operation of removing a portion of the first metal layer 121 and an operation of removing a portion of the third metal layer 123 may be performed. The operation of removing a portion of the first metal layer 121 may be performed in conjunction with Figure 7 and Figure 8 The corresponding operations in the method of manufacturing a printed circuit board according to an example shown in are the same, and the operation of removing a portion of the third metal layer 123 may be performed by the same method as in the operation of removing the first metal layer 121 .

[0074] In this case, since the first metal layer 121 and the third metal layer 123 may include different metal materials, the third metal layer 123 may not react in the operation of removing a portion of the first metal layer 121, and the first metal layer 121 may not react in the operation of removing the third metal layer 123. In addition, as described above, in the printed circuit board, the specific shapes of the first metal layer 121 and the third metal layer 123 are not limited to Fig. 9 The shapes shown in FIG. 1 and may vary.

[0075] In addition, since it can also be combined with Figure 7 and Figure 8 The same operations as those in the method for manufacturing a printed circuit board according to the example shown in FIG. 1 (except for the operation of forming the third metal layer 123 and the operation of removing a portion of the third metal layer 123) are applied to Fig. 9 A method of manufacturing a printed circuit board according to another example is shown in FIG. 8 , and thus a repeated description thereof will be omitted.

[0076] Fig.10 and Fig.11 is a cross-sectional view schematically illustrating a method of manufacturing a printed circuit board according to another example.

[0077] Reference Fig.10 , a method for manufacturing a printed circuit board according to another example may include an operation of forming a seed layer 140 on the first insulating layer 110. The seed layer 140 may be formed by performing electroless plating, and in some cases, the seed layer 140 may be formed by sputtering or the like. As a non-limiting example, the first insulating layer 110 to which the seed layer 140 is attached in the form of a copper foil may be used. The seed layer 140 is a temporary component and may not be retained in the finished product. The seed layer 140 may be used as a seed to supplement the third metal layer 123 and the first metal layer 121 in an operation of forming the second metal layer 122 to be described later. Therefore, in some cases, the operation of forming the seed layer 140 may be omitted. The seed layer 140 may include a metal material, and may be selected from a group of metal materials that are the same as the metal material of the first wiring layer 120, and preferably, may include copper (Cu), but the present disclosure is not limited thereto.

[0078] Thereafter, a dry film 201 may be formed on the seed layer 140. The operation of forming the dry film 201 may include the operations of forming a dry film 201' and exposing and developing the dry film 201'.

[0079] Thereafter, an operation of penetrating a portion of the seed layer 140 and the first insulating layer 110 to form the groove portion 300 may be performed. The operation of forming the groove portion 300 may be performed by penetrating the seed layer 140 and penetrating a portion of the first insulating layer 110, respectively, but the present disclosure is not limited thereto, and a portion of the seed layer 140 and the first insulating layer 110 may be penetrated simultaneously. When the groove portion 300 penetrating a portion of the first insulating layer 110 is formed in a separate process after the operation of penetrating the seed layer 140, the groove portion 300 may be formed in the same manner as in the operation of penetrating the seed layer 140. Figure 7 and Figure 8 The groove portion 300 is formed in the same manner as in the method of manufacturing a printed circuit board according to an example shown in , and mechanical processing may be performed while processing the seed layer 140 and the first insulating layer 110 at the same time. Since the seed layer 140 is disposed on the first insulating layer 110, when the groove portion 300 is formed in the first insulating layer 110, it may be more advantageous to adjust the degree of processing so that the groove portion 300 does not completely penetrate the first insulating layer 110.

[0080] Reference Fig.11 , an operation of forming the third metal layer 123 and an operation of forming the first metal layer 121 may be performed. In a printed circuit board according to another example, the third metal layer 123 and the first metal layer 121 are formed without removing the dry film 201, so that the third metal layer 123 may not contact the upper surface of the first insulating layer 110, and the third metal layer 123 and the first metal layer 121 may be arranged to extend onto the dry film 201.

[0081] Thereafter, an operation of forming the second metal layer 122 may be performed. The operation of forming the second metal layer 122 may be performed by electroplating using the first metal layer 121 as a seed. In addition, the second metal layer 122 may be plated on the first metal layer 121 disposed on the dry film 201 after the entirety of the groove portion 300 is filled. That is, the operation of forming the second metal layer 122 may be performed by plate plating or overplating, but the present disclosure is not limited thereto. Since the third metal layer 123 and the first metal layer 121 are disposed on the dry film 201, it may be difficult for the third metal layer 123 and the first metal layer 121 to cover both the opening of the dry film 201 and the groove portion 300 of the first insulating layer 110. That is, it may not be easy to form the third metal layer 123 and the first metal layer 121 on the inner wall of the groove portion 300, the inner wall of the opening of the dry film 201, and the upper surface of the dry film 201. Therefore, as a seed for forming the second metal layer 122, the third metal layer 123 and the first metal layer 121 may be insufficient. However, the seed layer 140 formed on the first insulating layer 110 can supplement the deficiency. That is, in the operation of pre-disposing the seed layer 140 on the first insulating layer 110 and forming the second metal layer 122, the seed layer 140 can serve as a supplement to the third metal layer 123 and the first metal layer 121.

[0082] Thereafter, an operation of removing a portion of the second metal layer 122 may be performed. The operation of removing a portion of the second metal layer 122 may be performed by removing an over-plated portion of the second metal layer 122, and may be performed using at least one of a chemical mechanical polishing (CMP) process and an etching process, but the present disclosure is not limited thereto. In this case, when the operation is performed by the chemical mechanical polishing process, a portion of the first metal layer 121 and a portion of the third metal layer 123 may also be removed and may have a flat surface (such as Figure 5 On the other hand, when this operation is performed by an etching process, the third metal layer 123 including a metal material different from the metal material of the second metal layer 122 may not react, the second metal layer 122 may be over-etched, and a portion of the first metal layer 121 including a metal material substantially the same as the metal material of the second metal layer 122 may be removed together to form a recessed area of ​​the first wiring layer 120 (as shown in FIG. Figure 6 ).

[0083] Thereafter, an operation of removing the seed layer 140 may be performed. Since the seed layer 140 may include the same metal material as the metal material of the first metal layer 121 and the second metal layer 122, the seed layer 140 may include a metal material different from the metal material of the third metal layer 123. Therefore, even in the operation of removing the seed layer 140, the third metal layer 123 may not react. That is, the third metal layer 123 may serve as an etching barrier that separates the first metal layer 121 and the second metal layer 122 from the seed layer 140. By removing the seed layer 140, the first wiring layer 120 may be completed.

[0084] Since it can also be Figure 7 and Figure 8 The method of manufacturing a printed circuit board according to an example shown in Fig. 9 The same operations as those in the method for manufacturing a printed circuit board according to another example shown in FIG. 1 (except for the formation of the first wiring layer 120 and the seed layer 140) are applied to Fig.10 and Fig.11 A method of manufacturing a printed circuit board according to another example is shown in FIG. 1 , and thus, a repeated description thereof is omitted.

[0085] In addition, as mentioned above, Fig.10 and Fig.11 In the method for manufacturing a printed circuit board according to another example shown in , a portion of the first metal layer 121 and a portion of the second metal layer 122 may be further removed in the operation of removing the seed layer 140, and as described above, in the operation of removing a portion of the second metal layer 122, the first wiring layer 120 may have an area in which the first metal layer 121 and the second metal layer 122 are recessed.

[0086] As described above, as one of the many effects of the present disclosure, a printed circuit board in which a wiring layer having a fine pitch can be realized can be provided.

[0087] As another one of the various effects of the present disclosure, it is possible to provide a printed circuit board in which a part of the wiring layer can be embedded and another part of the wiring layer can be protruded.

[0088] As another one of the various effects of the present disclosure, a printed circuit board that can improve reliability can be provided.

[0089] In the present disclosure, a cross-sectional view may refer to a view showing a cross-sectional shape when an object is cut vertically, or a view showing a cross-sectional shape when the object is observed from a side view. In addition, a plan view may refer to a view showing a plane shape when an object is cut horizontally, or a view showing a plane shape when the object is observed from a top view or a bottom view.

[0090] In the present disclosure, for convenience, "upper" in "upper side", "upper part", "upper surface", etc. is used to refer to the direction toward the surface on which the electronic component can be mounted based on the cross section of the drawing, and "lower" in "lower side", "lower part", "lower surface", etc. may be used to refer to the direction opposite to the above direction. However, this direction is defined for the convenience of explanation, and of course, the scope of the patent claims is not particularly limited by the description of this direction.

[0091] In the present disclosure, the meaning of connection is a concept including not only direct connection but also indirect connection through an adhesive layer or the like. In addition, the meaning of electrical connection is a concept including both the case of physical connection and the case of no physical connection. In addition, expressions such as "first", "second", etc. are used to distinguish one component from another component and do not limit the order and / or importance of the components. In some cases, without departing from the scope of the claims, a first component may be named a second component, and similarly, a second component may be named a first component.

[0092] In the present disclosure, "substantially" may be a concept including process errors and positional deviations occurring during the manufacturing process and errors during measurement, etc. For example, "substantially constant" may include not only a case of having exactly the same numerical value, but also a case of being substantially the same. As another example, "substantially vertical" may include not only a case of being completely vertical, but also a case of being substantially vertical. As another example, "substantially coplanar" may include not only a case of being located on exactly the same plane, but also a case of being located on substantially the same plane.

[0093] In the present disclosure, the width of a specific component can be measured by photographing a cross section cut along the stacking direction of the printed circuit board using a scanning electron microscope or the like. The width of a component can be interpreted as a distance passing horizontally through the specific component, but may include a measurement error or an error in a manufacturing process. For example, the width of a structure may be a value obtained by measuring an average horizontal distance at five arbitrary points.

[0094] In the present disclosure, the thickness of a specific component can be measured by photographing a cross section cut along the stacking direction of the printed circuit board using a scanning electron microscope or the like. The thickness of a component can be interpreted as a distance vertically passing through the component, but may include a measurement error or an error in the manufacturing process. For example, the thickness of a component may be a value obtained by averaging vertical distances measured at five arbitrary points.

[0095] In the present disclosure, the same material or substance may refer to not only the completely same material, but also the same type of material. Therefore, the composition of the material is substantially the same, but the specific composition ratio of the material may be slightly different.

[0096] The expression "example" used in this disclosure does not mean an identical example, but is provided to emphasize and illustrate different unique features. However, the examples presented above do not exclude the combination of features with other examples. For example, even if the content described in an example is not described in another example, it can be understood as a description related to another example unless there is an opposite or contradictory description in the other example.

[0097] The terms used in the present disclosure are only used to describe examples and are not intended to limit the present disclosure.At this time, unless the context clearly indicates otherwise, a singular expression includes a plural expression.

[0098] 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: a first insulating layer, comprising a groove portion disposed on an upper side of the first insulating layer; as well as a first wiring layer having an embedded portion embedded in the groove portion of the first insulating layer and a protruding portion protruding onto the first insulating layer, The width of the lower end of the protruding portion of the first wiring layer is narrower than the width of the upper end.

2. The printed circuit board according to claim 1, wherein: The first wiring layer includes: a first metal layer disposed on the inner wall of the groove portion and extending along the upper surface of the first insulating layer; and a second metal layer disposed on the first metal layer. The width of a portion of the first metal layer adjacent to the upper surface of the first insulating layer is narrower than the width of the upper surface of the first metal layer.

3. The printed circuit board according to claim 2, wherein: A width of a portion of the second metal layer adjacent to the upper surface of the first insulating layer is narrower than a width of the upper surface of the second metal layer.

4. The printed circuit board according to claim 2, wherein: At least a portion of a side surface of the second metal layer in the protruding portion of the first wiring layer is an inclined surface.

5. The printed circuit board according to claim 4, wherein: At least a portion of a side surface of the first metal layer in the protruding portion of the first wiring layer is an inclined surface, and An inclination angle between the inclined surface of the first metal layer and the upper surface of the first insulating layer is the same as an inclination angle between a virtual extension surface of the inclined surface of the second metal layer and the upper surface of the first insulating layer.

6. The printed circuit board according to claim 2, wherein: The first metal layer includes the same metal as the second metal layer.

7. The printed circuit board according to claim 2, wherein: The first wiring layer further includes a third metal layer disposed below the first metal layer, and The third metal layer includes a metal different from that of the first metal layer.

8. The printed circuit board according to any one of claims 1 to 7, wherein: The embedded portion of the first wiring layer has a width narrower than a width of the protruding portion of the first wiring layer.

9. The printed circuit board according to any one of claims 1 to 7, further comprising: The second wiring layer is disposed below the first wiring layer and is spaced apart from the first wiring layer.

10. A printed circuit board, comprising: a first insulating layer, comprising a groove portion disposed on an upper side of the first insulating layer; a first wiring layer having an embedded portion embedded in the groove portion of the first insulating layer and a protruding portion protruding onto the first insulating layer, and a second wiring layer embedded in the first insulating layer and disposed below the first wiring layer and spaced apart from the first wiring layer, The wiring density of the first wiring layer is greater than the wiring density of the second wiring layer.

11. The printed circuit board according to claim 10, wherein: The protruding portion of the first wiring layer has a constant width.

12. The printed circuit board according to claim 11, wherein The width of an upper portion of the embedded portion of the first wiring layer is the same as the width of a lower portion of the protruding portion of the first wiring layer.

13. The printed circuit board according to claim 10, wherein: The first wiring layer includes: a first metal layer disposed on an inner wall of the groove portion of the first insulating layer and extending to protrude above the first insulating layer; a second metal layer disposed on the first metal layer; and a third metal layer disposed on the second metal layer.

14. The printed circuit board according to claim 13, wherein: The second metal layer includes a metal different from a metal of the first metal layer.

15. The printed circuit board according to claim 14, wherein: The second metal layer and the third metal layer include the same metal as each other.

16. The printed circuit board according to claim 13, wherein: The first wiring layer has a region in which at least a portion of the second metal layer and at least a portion of the third metal layer are recessed.

17. A printed circuit board comprising: an insulating layer, comprising a groove portion disposed on an upper side of the insulating layer; as well as a wiring layer having an embedded portion embedded in the groove portion of the insulating layer and a protruding portion protruding onto the insulating layer, The wiring layer includes: a first metal layer, which is arranged on the inner wall of the groove portion of the insulating layer; a second metal layer, which is arranged on the first metal layer; and a third metal layer, which is arranged on the second metal layer. Each of the first metal layer, the second metal layer, and the third metal layer includes a portion disposed in the groove portion of the insulating layer and a portion protruding onto the insulating layer, and The second metal layer includes a metal different from a metal of the first metal layer.

18. The printed circuit board according to claim 17, wherein: The second metal layer includes a metal different from a metal of the third metal layer.

19. The printed circuit board according to claim 18, wherein The first metal layer includes a metal different from a metal of the third metal layer.

20. The printed circuit board according to claim 17, wherein The second metal layer and the third metal layer include the same metal as each other.

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