Patent ID: 12256492

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The shapes and sizes of elements in the drawings may be exaggerated or reduced for clearer description.

Electronic Device

FIG.1is a schematic block diagram illustrating an example of an electronic device system.

Referring toFIG.1, an electronic device1000may accommodate a mainboard1010therein. The mainboard1010may include chip related components1020, network related components1030, other components1040, and the like, physically or electrically connected thereto. These components may be connected to other electronic components to be described below to form various signal lines1090.

The chip related components1020may include a memory chip such as a volatile memory (for example, a dynamic random access memory (DRAM)), a non-volatile memory (for example, a read only memory (ROM)), a flash memory, or the like; an application processor chip such as a central processor (for example, a central processing unit (CPU)), a graphics processor (for example, a graphics processing unit (GPU)), a digital signal processor, a cryptographic processor, a microprocessor, a microcontroller, or the like; and a logic chip such as an analog-to-digital (ADC) converter, an application-specific integrated circuit (ASIC), or the like. However, the chip related components1020are not limited thereto, and may also include other types of chip related electronic components. In addition, the chip related components1020may be combined with each other. The chip-related component1020may be in the form of a package including the above-described chip or electronic component.

The network related components1030may include protocols such as wireless fidelity (Wi-Fi) (Institute of Electrical And Electronics Engineers (IEEE) 802.11 family, or the like), worldwide interoperability for microwave access (WiMAX) (IEEE 802.16 family, or the like), IEEE 802.20, long term evolution (LTE), evolution data only (Ev-DO), high speed packet access+(HSPA+), high speed downlink packet access+(HSDPA+), high speed uplink packet access+(HSUPA+), enhanced data GSM environment (EDGE), global system for mobile communications (GSM), global positioning system (GPS), general packet radio service (GPRS), code division multiple access (CDMA), time division multiple access (TDMA), digital enhanced cordless telecommunications (DECT), Bluetooth, 3G, 4G, and 5G protocols, and any other wireless and wired protocols, designated after the abovementioned protocols. However, the network related components1030are not limited thereto, and may also include a variety of other wireless or wired standards or protocols. In addition, the network related components1030may be combined with each other, together with the chip related components1020described above.

Other components1040may include a high frequency inductor, a ferrite inductor, a power inductor, ferrite beads, a low temperature co-fired ceramic (LTCC), an electromagnetic interference (EMI) filter, a multilayer ceramic capacitor (MLCC), or the like. However, other components1040are not limited thereto, and may also include passive components in the form of a chip component used for various other purposes, or the like. In addition, other components1040may be combined with each other, together with the chip related components1020or the network related components1030described above.

Depending on a type of the electronic device1000, the electronic device1000may include other electronic components that may or may not be physically or electrically connected to the mainboard1010. Examples of other electronic components include a camera module1050, an antenna module1060, a display device1070, a battery1080, and the like. However, other electronic components are not limited thereto, and may include, for example, 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, and the like. In addition thereto, these other components may also include other electronic components used for various purposes depending on a type of electronic device1000, or the like.

The electronic device1000may be a smartphone, a personal digital assistant (PDA), a digital video camera, a digital still camera, a network system, a computer, a monitor, a tablet PC, a laptop PC, a netbook PC, a television, a video game machine, a smartwatch, an automotive component, or the like. However, the electronic device1000is not limited thereto, but may be any other electronic device processing data.

FIG.2is a schematic perspective view illustrating an example of an electronic device.

Referring toFIG.2, the electronic device may be, for example, a smartphone1100. A motherboard1110is accommodated inside the smartphone1100, and various components1120are physically and/or electrically connected to the motherboard1110. Also, other components that may or may not be physically and/or electrically connected to the motherboard1110, such as a camera module1130and/or a speaker1140, are accommodated in the smartphone1100. A portion of the components1120may be the aforementioned chip-related component, for example, the component package1121, but the present disclosure is not limited thereto. The component package1121may be in the form of a printed circuit board on which electronic components including active components and/or passive components are surface-mounted. Alternatively, the component package1121may be in the form of a printed circuit board in which active components and/or passive components are embedded. On the other hand, the electronic device is not necessarily limited to the smartphone1100, and may also be other electronic devices as described above.

Printed Circuit Board

FIG.3is a cross-sectional view schematically illustrating an example of a printed circuit board, andFIGS.4A to6Bare cross-sectional views schematically illustrating effects of the printed circuit board ofFIG.3, respectively.

Referring to the drawings, a printed circuit board100A according to an example includes a first insulating layer110, a metal pad130disposed on the first insulating layer110, and a second insulating layer140disposed on the first insulating layer110and covering a portion of the side surface of the metal pad130. The metal pad130includes a first metal portion133and a second metal portion135, and if necessary, may further include a seed metal layer120disposed on the first insulating layer110and/or a surface metal layer150disposed on the metal pad130. The first metal portion133is disposed on the first insulating layer110, in detail, on the seed metal layer120. The second metal portion135is disposed on the first metal portion133and is integrated with the first metal portion133without a boundary therebetween.

On the other hand, as illustrated inFIG.4Aas an example, in the case of a metal pad1300formed by a general plating process, the edge of the upper surface of the metal pad1300may have a rounded shape by a seed etchant, or the like. In addition, the metal pad1300may have a tapered shape in which the width of the upper surface is narrower than the width of the lower surface. In this case, the actual contact area of wire bonding may be relatively small.

Meanwhile, as illustrated inFIG.4Bas an example, in the case of the printed circuit board100A according to an example of the present disclosure, damage to the metal pad130by a seed etchant or the like may be prevented with a barrier metal layer including a metal different from the metal pad130. Accordingly, respective side surfaces of the first metal portion133and the second metal portion135may have a substantially vertical shape, and the edges of respective upper surfaces of the first metal portion133and the second metal portion135may have a substantially angular shape. The side surface of the substantially vertical form may mean having an angle approximately perpendicular to the bottom surface, and also, the edge in the substantially angular shape may indicate that the edge is not substantially round. Therefore, the problem in which the actual contact area of wire bonding is narrowed may be efficiently prevented.

Meanwhile, as illustrated inFIG.5Aas an example, the metal pad1300formed by a general plating process may have a surface metal layer1500formed on the side surface as well as the upper surface, and therefore, may be difficult to secure a space margin between the surface metal layers1500on the adjacent metal pads1300. Therefore, there may be a limit to the implementation of the fine pitch bonding finger with this structure.

Meanwhile, as illustrated inFIG.5Bas an example, in the printed circuit board100A according to an example of the present disclosure, a width W2of the second metal portion135in the cross-section may be narrower than a width W1of the first metal portion133in the cross-section. In the case in which the width in the cross section is not constant, the average width may be compared. In addition, the second insulating layer140may cover at least a portion of the side surface of the first metal portion133, but may be spaced apart from the upper surface of the first metal portion133. For example, the second insulating layer140may not cover the upper surface of the first metal portion133, and the upper surface of the second insulating layer140may be substantially coplanar with the upper surface of the first metal portion133. In this case, with reference to a surface of the first insulating layer110on which the metal pad130is disposed, a height of the second insulating layer140may be smaller than a height of the second metal portion135. Being substantially coplanar may include not only a case in which the coplanar is perfectly coplanar, but also a case in which the coplanar is substantially coplanar due to a process error or the like. Accordingly, the surface metal layer150may selectively cover at least a portion of each of the upper surface and the side surface of the second metal portion135. In this case, a space margin between the surface metal layers150on the adjacent metal pads130may be sufficiently secured. Therefore, it may be more advantageous for the implementation of fine pitch bonding fingers.

On the other hand, as illustrated inFIG.6Aas an example, in the metal pad1300formed by a general plating process, due to the undercut between the metal pad1300and an insulating material1101, occurring in the etching process of the seed metal layer1200, a surface metal layer1500, such as a hard nickel layer1530, may be disposed in a notch region in which stress is concentrated, and may be in contact with the insulating material1101, to be vulnerable to external impact. For example, a lift problem of the metal pad1300may occur due to warpage of the substrate due to thermal expansion and contraction.

Meanwhile, as illustrated inFIG.6Bas an example, in the printed circuit board100A according to an example of the present disclosure, the second insulating layer140may be disposed on the first insulating layer110to cover side surfaces of the seed metal layer120and the first metal portion133. The second insulating layer140may include, for example, a solder resist material of which the thickness may be adjusted to selectively cover the first metal portion133among the first metal portion133and the second metal portion135by half development. Accordingly, a groove portion h formed in at least a portion of the side surface of the seed metal layer120, for example, the groove portion h having a tapered upper surface may be filled with the second insulating layer140. Because the surface metal layer150does not extend between the second insulating layer140and the first metal portion133, the second insulating layer140and the first metal portion133may be in contact with each other. Because the surface metal layer150does not extend between the second insulating layer140and the seed metal layer120, the second insulating layer140and the seed metal layer120may be in contact with each other at a region having the groove portion h. In this case, the second insulating layer140may alleviate the above-described external impacts, and therefore, the lifting problem of the metal pad130and the like may be effectively prevented.

On the other hand, the metal pad130may be provided in plural, and the surface metal layer150may also be provided as a plurality of surface metal layers150and may be disposed on the metal pad130. In this case, in the printed circuit board100A according to an example, a gap g1between the first metal portions133of two adjacent metal pads130among the plurality of metal pads130may be substantially the same as a gap g2between second surface metal layers155of two surface metal layers150respectively disposed on the two adjacent metal pads130among the plurality of surface metal layers150. The gap may be a value measured at an intermediate point of the target component with respect to the thickness direction or the lamination direction on the cross-section. Being substantially the same gap may include not only the case in which the intervals are completely identical, but also the case in which the intervals are approximately the same due to a process error. For example, the surface metal layer150may be formed to have a thickness corresponding to the width thereof without departing from the upper surface of the first metal portion133. In this case, space margin management may be more effective.

Hereinafter, the components of the printed circuit board100A according to an example will be described in more detail with reference to the drawings.

The first insulating layer110may include an insulating material. The insulating material may include thermosetting resins such as epoxy resins, a thermoplastic resin such as polyimide, or materials containing inorganic fillers, organic fillers and/or glass fibers (Glass Fiber, Glass Cloth, and/or Glass Fabric) together with these resins. The insulating material may be a photosensitive material and/or a non-photosensitive material. For example, as the insulating material, insulation materials of Solder Resist (SR), Ajinomoto Build-up Film (ABF), Prepreg (PPG), Resin Coated Copper (RCC), and Copper Clad Laminate (CCL) may be used, but is not limited thereto, and other polymer materials may be used in addition thereto.

The seed metal layer120may include a metal material. Metal materials may include copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), and/or alloys thereof, and in detail, may include copper (Cu), but the present disclosure is not limited thereto. The seed metal layer120may be relatively thinner than the metal pad130and may be an electroless plating layer (or chemical copper), but the present disclosure is not limited thereto. For example, the seed metal layer120may be copper foil or the like.

The metal pad130may include a metal material. The first and second metal portions133and135of the metal pad130may include the same metal material. Metal materials may include copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), and/or alloys thereof, and in detail, may include copper (Cu), but the present disclosure is not limited thereto. The metal pad130may perform various functions according to a design, and for example, may include a ground pad, a power pad, a signal pad, and the like. In this case, the signal pad may include a pad for electrical connection of various signals except for ground and power, for example, a data signal. The metal pad130may be an electrolytic plating layer (or electrolytic copper), and in this case, the first and second metal portions133and135may be simultaneously formed by plating.

The second insulating layer140may include an insulating material. The insulating material may include a resist, for example, a solder resist. The solder resist may contain an insulating resin and a filler, but may not contain glass fibers. The insulating resin may be a photosensitive insulating resin, and the filler may be an inorganic filler and/or an organic filler, but is not limited thereto. However, the material of the second insulating layer140is not limited thereto, and other polymer materials may be used if necessary.

The surface metal layer150may include a metal material. The first and second surface metal layers153and155of the surface metal layer150may include different metal materials. For example, the first surface metal layer153may include nickel (Ni), and the second surface metal layer155may include gold (Au), but is not limited thereto, and for example, may include other metal materials such as silver (Ag) and tin (Sn). The first surface metal layer153may be thicker than the second surface metal layer155, but the present disclosure is not limited thereto. The surface metal layer150may be formed by, for example, electrolytic gold plating, electroless gold plating, Organic Solderability Preservative (OSP) or electroless tin plating, electroless silver plating, electroless nickel plating/substitution gold plating, Direct Immersion Gold (DIG) plating, Hot Air Solder Leveling (HASL), or the like.

On the other hand, the printed circuit board100A according to an example may be applied not only to such a single-layer board, but also to a multi-layer board. For example, the first insulating layer110, the seed metal layer120, the metal pad130, the second insulating layer140, and the surface metal layer150described above may be applied to the outermost layer of the multilayer substrate, and for example, may be applied to a package substrate in which a bonding pad is formed in a wire bonding area of the outermost layer of a multilayer printed circuit board.

FIGS.7A to7Lare process diagrams schematically illustrating an example of manufacturing the printed circuit board ofFIG.3.

Referring toFIG.7A, a first insulating layer110having a first metal layer121disposed thereon is prepared. The first metal layer121may be formed by electroless plating (or chemical plating). Alternatively, the first metal layer121may be formed by laminating a copper foil or the like on the upper surface of the first insulating layer110.

Referring toFIG.7B, a resist film210having an opening210hexposing the first metal layer121is formed on the first metal layer121. For example, the resist film210is formed on the first metal layer121by a dry film lamination method or the like, and after partially exposing the resist film210using a mask, the opening210hmay be formed by developing the exposed resist film210. The resist film210may include a photosensitive material, for example, may be a negative type resist film, but the present disclosure is not limited thereto.

Referring toFIG.7C, a second metal layer131filling at least a portion of the opening210his formed on the first metal layer121exposed through the opening210h. The second metal layer131may be formed by an electrolytic plating (or electroplating). A portion of the uppermost portion of the opening210hmay remain unfilled with the second metal layer131.

Referring toFIG.7D, a barrier metal layer220is formed on the second metal layer131in the opening210h. The barrier metal layer220may include a metal material, for example, nickel (Ni), different from a material of the first and second metal layers121and131. The barrier metal layer220may be formed by electrolytic plating (or electroplating). The uppermost portion of the opening210hmay be filled with the barrier metal layer220.

Referring toFIG.7E, the resist film210is removed. For example, the resist film210may be removed by a peeling process. As the peeling process, physical peeling or chemical peeling using a stripper may be used.

Referring toFIG.7F, at least a partial region of the first metal layer121is etched. For example, a region of the first metal layer121in which the second metal layer131is not formed may be removed by seed etching using an etchant. As a result, the seed metal layer120may be formed between the first insulating layer110and the second metal layer131. The etching is performed using the barrier metal layer220, thereby preventing the side surface of the second metal layer131from being tapered and the edge of the upper surface of the second metal layer131from being rounded.

Referring toFIG.7G, a second insulating layer140is formed on the first insulating layer110, to cover respective side surfaces of the seed metal layer120, the second metal layer131, and the barrier metal layer220. The second insulating layer140may be formed by coating a solder resist composition on the first insulating layer110and then drying the same, but the present disclosure is not limited thereto.

Referring toFIG.7H, at least a portion of the second insulating layer140is removed. The thickness of the second insulating layer140may be thinner than the thickness of the second metal layer131. For example, the upper surface of the second insulating layer140may be disposed to be lower than the upper surface of the second metal layer131. A half development process may be used to partially remove the second insulating layer140.

Referring toFIG.7I, at least a portion of the second metal layer131is etched to form the metal pad130including the first and second metal portions133and135. At this time, the side of the first metal portion133is covered with the second insulating layer140, and the second metal portion135may be etched to have relatively narrower width on the cross-section of the second metal portion135. In addition, the presence of the barrier metal layer220may prevent the side surface of the second metal portion135from being tapered and the edge of the upper surface of the second metal portion135from being rounded.

Referring toFIG.7J, the barrier metal layer220is etched. For example, an etchant selectively reacting with the barrier metal layer220may be used.

Referring toFIG.7K, a first surface metal layer153is formed. The first surface metal layer153may be formed by nickel (Ni) plating, but the present disclosure is not limited thereto. The first metal portion133is covered by the second insulating layer140, and the first surface metal layer153may be formed to selectively cover the upper surface and the side surface of the second metal portion135.

Referring toFIG.7L, a second surface metal layer155is formed. The second surface metal layer155may be formed by gold (Au) plating, but the present disclosure is not limited thereto. The second surface metal layer155may be formed to cover the surface of the first surface metal layer153.

The printed circuit board100A according to the above-described example may be formed through a series of processes, but the manufacturing process is not necessarily limited thereto.

FIG.8is a cross-sectional view schematically illustrating another example of a printed circuit board.

Referring to the drawings, a printed circuit board100B according to another example has a thinner surface metal layer150as compared to the printed circuit board100A according to the above-described example. For example, the first surface metal layer153may be formed thinner to cover an upper surface of the first metal portion133, a side surface of the second metal portion135, and an upper surface of the second metal portion135.

On the other hand, the metal pad130may be present in plural, and the surface metal layer150may also be provided as a plurality of surface metal layers150to be disposed on the metal pads130respectively. In this case, in the printed circuit board100B according to another example, a gap g1between the first metal portions133of two adjacent metal pads130among the plurality of metal pads130may be less than a gap g2between second surface metal layers155of two surface metal layers150respectively disposed on the two adjacent metal pads130from among the plurality of surface metal layers150. The gap may be a value measured at an intermediate point of the target component with respect to the thickness direction or the lamination direction on the cross-section. In this case, a structure more suitable for a relatively narrower pitch specification may be obtained.

In addition thereto, in related to other descriptions, for example, the contents described in the printed circuit board100A according to the above-described example may be applied to the printed circuit board100B according to another example unless contradictory, and a redundant description thereof will be omitted. In addition, the manufacturing example of the printed circuit board100A according to the above-described example may be similarly applied to the manufacturing of the printed circuit board100B according to another example.

FIG.9is a cross-sectional view schematically illustrating another example of a printed circuit board.

Referring to the drawings, a printed circuit board100C according to another example has a thicker surface metal layer150than the thickness of the printed circuit board100A according to the above-described example. For example, the first surface metal layer153may be formed to be relatively thicker and may be disposed to extend onto the upper surface of the second insulating layer140.

On the other hand, the metal pad130may be present in plural, and the surface metal layer150may also be provided as a plurality of surface metal layers150to be disposed on the metal pads130respectively. In this case, in the printed circuit board100C according to another example, a gap g1between first metal portions133of two adjacent metal pads130among the plurality of metal pads130may be greater than a gap g2between second surface metal layers155of two surface metal layers150respectively disposed on the two adjacent metal pads130from among the plurality of surface metal layers150. The gap may be a value measured at an intermediate point of the target component with respect to the thickness direction or the lamination direction on the cross-section. In this case, multiple wire bonding is possible on one bonding finger, and thus, a structure more suitable for specifications requiring relatively high-density signal transmission may be provided.

In addition thereto, in related to other descriptions, for example, the contents described in the printed circuit board100A according to the above-described example may be applied to the printed circuit board100C according to another example unless contradictory, and a redundant description thereof will be omitted. In addition, the manufacturing example of the printed circuit board100A according to the above-described example may be similarly applied to the manufacturing of the printed circuit board100C according to another example.

As set forth above, as an effect according to an example of the present disclosure, a printed circuit board in which a fine pitch bonding finger may be implemented may be provided.

As another effect among various effects of the present disclosure, a printed circuit board in which damage to the pad from seed etching or pretreatment may be prevented may be provided.

As another effect among the various effects of the present disclosure, a printed circuit board in which a sufficient space margin may be secured even after a metal surface treatment may be provided.

As another effect of the various effects of the present disclosure, a printed circuit board in which a problem caused by an external impact in the stress concentration space between the pad and the insulating material may be prevented may be provided.

In the present disclosure, ‘on the cross-section’ may indicate a cross-sectional shape when the object is vertically cut, or a cross-sectional shape when the object is viewed from a side-view. In addition, the meaning on a plane may be a shape when the object is horizontally cut, or a flat shape when the object is viewed from a top-view or a bottom-view.

In the present disclosure, the lower side, the lower portion, the lower surface, and the like are used to refer to the direction toward the mounting surface of the semiconductor package including the organic interposer based on the cross section of the drawing for convenience, and the upper side, upper portion, upper surface and the like are used in the direction opposite thereto. However, this is to define the direction for convenience of explanation, and the scope of the claims is not limited by the description in this direction.

The meaning of being connected in the present disclosure is a concept including not only directly connected, but also indirectly connected through an adhesive layer or the like. In addition, the meaning of being electrically connected is a concept including both the case of being physically connected and the case of not being connected. In addition, expressions such as first, second, and the like are used to distinguish one component from another, and do not limit the order and/or importance of the corresponding components. In some cases, without departing from the scope of rights, the first component may be named as the second component, and similarly, the second component may be named as the first component.

The expression “an example” used in the present disclosure does not mean the same embodiment, and is provided to emphasize and explain different unique features. However, the examples presented above are not excluded from being implemented in combination with features of other examples. For example, even if a matter described in one specific example is not described in another example, it may be understood as a description related to another example unless a description contradicts the matter in another example.

The terminology used in the present disclosure is used to describe an example only, and is not intended to limit the present disclosure. In this case, the singular expression includes the plural expression unless the context clearly dictates otherwise.

While embodiments have been illustrated and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present disclosure as defined by the appended claims.