Printed circuit board

Abstract

One of the objectives of the present invention is to provide a printed circuit board with improved structural stability, such as that of conductive posts. [Solution] One embodiment of the present invention provides a printed circuit board comprising an insulating layer, a pad portion disposed on the insulating layer, a protective layer disposed on the insulating layer and the pad portion, a conductive post disposed on the pad portion and protruding from the protective layer, and an insulating film formed on a part of the surface of the conductive post.

Description

Technical Field

[0001] The present invention relates to a printed circuit board.

Background Art

[0002] Recently, in order to meet the trend of weight reduction and miniaturization of mobile devices, there is an increasing need to achieve thinner, lighter, shorter, and smaller printed circuit boards implemented therein. On the other hand, an undercut phenomenon occurs in the process of realizing a fine circuit while the mobile device is being thinned, lighter, shorter, and smaller, which may cause defects in the fine circuit. In response to the technical requirements for this, research has been continuously conducted to improve reliability while realizing a circuit with a fine line width and pitch.

Summary of the Invention

Problems to be Solved by the Invention

[0003] One object of the present invention is to provide a printed circuit board with improved structural stability of conductive posts and the like.

Means for Solving the Problems

[0004] To solve the above problems, one embodiment of the present invention provides a printed circuit board including an insulating layer, a pad portion disposed on the insulating layer, a protective layer disposed on the insulating layer and the pad portion, a conductive post disposed on the pad portion and protruding outward from the protective layer, and an insulating film formed on a part of the surface of the conductive post.

[0005] In one embodiment, at least a part of the insulating film can be interposed between the conductive post and the protective layer.

[0006] In one embodiment, the insulating film can contact the conductive post and the protective layer.

[0007] In one embodiment, the insulating film can be formed on at least a portion of the side surface of the conductive post that is not covered by the protective layer.

[0008] In one embodiment, at least a portion of the upper surface of the conductive post can be exposed without being covered by the insulating film.

[0009] In one embodiment, the insulating film can also be formed on the surface of the pad portion.

[0010] In one embodiment, the present invention further includes a conductive layer disposed on the insulating layer, and the insulating film can also be formed on the surface of the conductive layer.

[0011] In one embodiment, the insulating film can also be formed on the upper surface of the insulating layer.

[0012] In one embodiment, the insulating film can be extended to the surface of the pad portion and the insulating layer to form an overall integrated structure.

[0013] In one embodiment, the insulating film can have a shape that conforms to the surface of the conductive post, the pad portion, and the insulating layer.

[0014] In one embodiment, the insulating film can be an atomic layer deposited layer.

[0015] In one embodiment, the insulating film can include Al2O3.

[0016] In one embodiment, the conductive cap layer may be further disposed on the conductive post and electrically connected to the conductive post.

[0017] In one embodiment, the conductive cap layer can be formed in a manner that does not cover the sides of the conductive post.

[0018] In one embodiment, the conductive cap layer can be formed in a range that does not cover the side surface of the insulating film.

[0019] On the other hand, another embodiment of the present invention provides a printed circuit board including an insulating layer, a pad portion disposed on the insulating layer, a protective layer disposed on the insulating layer and the pad portion, a conductive post disposed on the pad portion, and an insulating film formed on a part of the surfaces of the pad portion and the conductive post.

Advantages of the Invention

[0020] In the case of a printed circuit board according to an example of the present invention, the structural stability of a conductive post or the like can be improved.

Brief Description of the Drawings

[0021] [Figure 1] It is a block diagram schematically showing an example of an electronic device system. [Figure 2] It is a perspective view schematically showing an example of an electronic device. [Figure 3] It is a cross-sectional view schematically showing an example of a printed circuit board. [Figure 4] It is a plan view showing a conductive post and its peripheral region. [Figure 5] An example of a method for manufacturing a printed circuit board is shown. [Figure 6] An example of a method for manufacturing a printed circuit board is shown. [Figure 7] An example of a method for manufacturing a printed circuit board is shown. [Figure 8] An example of a method for manufacturing a printed circuit board is shown. [Figure 9] An example of a method for manufacturing a printed circuit board is shown. [Figure 10] An example of a method for manufacturing a printed circuit board is shown. [Figure 11] It is a cross-sectional view showing a printed circuit board according to a modified example.

Embodiments for Carrying Out the Invention

[0022] Embodiments of the present invention will be described below with reference to specific embodiments and accompanying drawings. However, embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, embodiments of the present invention are provided to give a more complete explanation of the present invention to a person of ordinary skill. Accordingly, the shapes and sizes of elements in the drawings may be exaggerated for the sake of clearer explanation, and elements indicated by the same reference numerals in the drawings are the same elements.

[0023] electronic equipment Figure 1 is a block diagram illustrating an example of an electronic equipment system.

[0024] Referring to the drawing, the electronic device 1000 houses the main board 1010. The main board 1010 is physically and / or electrically connected to chip-related components 1020, network-related components 1030, and other components 1040, etc. These are also connected to other electronic components, which will be described later, to form various signal lines 1090.

[0025] The chip-related components 1020 include, but are not limited to, memory chips such as volatile memory (e.g., DRAM), non-volatile memory (e.g., ROM), and flash memory; application processor chips such as central processors (e.g., CPUs), graphics processors (e.g., GPUs), digital signal processors, encryption processors, microprocessors, and microcontrollers; and logic chips such as analog-to-digital converters and ASICs (application-specific ICs). It is also true that these chip-related components 1020 may be combined with each other. The chip-related components 1020 may also be in the form of a package containing the aforementioned chips and electronic components.

[0026] Network-related component 1030 includes, but is not limited to, any other wireless and wired protocols specified in Wi-Fi (IEEE 802.11 family, etc.), WiMAX (IEEE 802.16 family, etc.), IEEE 802.20, LTE (long term evolution), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE, GSM, GPS, GPRS, CDMA, TDMA, DECT, Bluetooth®, 3G, 4G, 5G, and later. It also includes any other wireless or wired standards and protocols. Of course, network-related component 1030 may be combined with chip-related component 1020.

[0027] Other components 1040 include high-frequency inductors, ferrite inductors, power inductors, ferrite beads, LTCCs (low-temperature co-firing ceramics), EMI (electromagnetic interference) filters, MLCCs (multi-layer ceramic condensers), etc. However, they are not limited to these, and may also include passive elements in chip component form used for a variety of other applications. Of course, other components 1040 may be combined with chip-related components 1020 and / or network-related components 1030.

[0028] Depending on the type of electronic device 1000, it may include other electronic components that are physically and / or electrically connected to the main board 1010, or not. Examples of other electronic components include a camera module 1050, an antenna module 1060, a display 1070, a battery 1080, etc. However, it is not limited to these, and may also include audio codecs, video codecs, power amplifiers, compasses, accelerometers, gyroscopes, speakers, mass storage devices (e.g., hard disk drives), CDs (compact disks), DVDs (digital versatile disks), etc. Of course, other electronic components used for various purposes may also be included depending on the type of electronic device 1000.

[0029] The electronic device 1000 may be a smartphone, personal digital assistant, digital video camera, digital still camera, network system, computer, monitor, tablet, laptop, netbook, television, video game, smartwatch, automobile, etc. However, it is not limited to these, and of course it may be any other electronic device that processes data.

[0030] Figure 2 is a schematic perspective view showing an example of an electronic device.

[0031] Referring to the drawings, the electronic device could be, for example, a smartphone 1100. Inside the smartphone 1100 is a motherboard 1110, to which various components 1120 are physically and / or electrically connected. Other components, such as a camera module 1130 and / or a speaker 1140, may or may not be physically and / or electrically connected to the motherboard 1110. Some of the components 1120 may be the chip-related components described above, and may, for example, be a component package 1121, but is not limited to this. The component package 1121 may be in the form of a printed circuit board on which electronic components, including active and / or passive components, are surface-mounted. Alternatively, the component package 1121 may be in the form of a printed circuit board with the active and / or passive components embedded within it. On the other hand, the electronic device is not necessarily limited to a smartphone 1100, and of course may be other electronic devices as described above.

[0032] Printed circuit board Figure 3 is a schematic cross-sectional view showing an example of a printed circuit board. Figure 4 is a plan view showing a conductive post and its surrounding area. Referring to Figures 3 and 4, the printed circuit board 100 according to this embodiment includes an insulating layer 101, a pad portion 111, a protective layer 121, a conductive post 131, and an insulating film 141. Here, the insulating film 141 is formed on a part of the surface of the conductive post 131. The insulating film 141 effectively protects the conductive post 131 from external forces, etc., thereby improving structural stability. Furthermore, by using the insulating film 141, surface treatment processes that increase the surface roughness of the conductive post 131 and the pad portion 111 can be eliminated, thereby reducing signal loss. The main components of the printed circuit board 100 will be described in detail below. In the drawings, the first direction D1 can be defined as the thickness direction of the insulating layer 101, and the second and third directions D2 and D3 can be defined as directions perpendicular to the first direction D1 and perpendicular to each other.

[0033] The insulating layer 101 may contain an insulating material and can be implemented in a multilayer structure. Here, the insulating material of the insulating layer 101 may include a thermosetting resin such as epoxy resin, a thermoplastic resin such as polyimide, or materials such as inorganic fillers, organic fillers and / or glass fibers (glass fiber, glass cloth, and / or glass fabric) together with such a resin. The insulating material may be a photosensitive material and / or a non-photosensitive material. For example, insulating materials such as SR (solder resist), ABF (Ajinomoto build-up film), FR-4, BT (bismaleimide triazine), PPG (prepreg), RCC (resin-coated copper foil), and CCL (copper-clad laminate) can be used, but are not limited to these, and other polymer materials can also be used.

[0034] The pad portion 111 can be provided as an area arranged on the insulating layer 101 and connected to semiconductor chips, packages, interposers, etc. In this case, at least a portion of the pad portion 111 can be embedded in the insulating layer 101. As shown in the embodiment in Figure 4, the pad portion 111 can have a cylindrical or cylindrical shape. In addition to the pad portion 111, the printed circuit board 100 may further include a conductive layer 112 on the insulating layer 101. The pad portion 111 and the conductive layer 112 may contain metals with high electrical conductivity, such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), and / or alloys thereof, and can be implemented in a multilayer structure if necessary. Furthermore, the insulating layer 101 may further include conductive layers, pads, conductive vias, etc., arranged at different levels, in addition to the pad portion 111 and the conductive layer 112.

[0035] The protective layer 121 is placed on the insulating layer 101 and the pad portion 111, and can protect the pad portion 111, the conductor layer 112, the conductive post 131, etc. The protective layer 121 may include solder resist material, and as an example, it may include a photosensitive insulating material.

[0036] The conductive post 131 is positioned on the pad portion 111 and can be provided as a connection area with other printed circuit boards, chips, etc. As shown in the embodiment in Figure 4, the conductive post 131 can have a cylindrical or cylindrical shape. The conductive post 131 has a form that protrudes outward from the protective layer 121, i.e., includes a protruding portion P. Here, a form that protrudes outward from the protective layer 121 means that at least a portion of the conductive post 131 is located further away from the insulating layer 101 than from the protective layer 121. In the case of a conductive post 131 with such an outward protruding form, damage due to external forces may occur during the handling, driving, etc., of the printed circuit board 100, which may lead to a decrease in the reliability of the printed circuit board 100. In this embodiment, an insulating film 141 is formed on a part of the surface of the conductive post 131 so that the conductive post 131 can be protected from external influences, etc. In this case, as shown in the embodiment, at least a portion of the insulating film 141 can be interposed between the conductive post 131 and the protective layer 121. The insulating film 141 can be in contact with the conductive post 131 and the protective layer 121. Furthermore, the insulating film 141 can be formed on the side surface of the conductive post 131 in areas not covered by the protective layer 121, i.e., on at least a portion of the protruding portion P. Figure 3 shows a configuration where the insulating film 141 is formed on the entire side surface of the protruding portion P, but the insulating film 141 can also be formed on only a portion of the side surface of the protruding portion P.

[0037] Since the conductive post 131 is provided as a mounting area for semiconductor chips and the like, at least a portion of the upper surface of the conductive post 131 can be exposed and not covered by the insulating film 141. Figure 3 shows a configuration in which the entire upper surface of the conductive post 131 is exposed, but a portion of the upper surface of the conductive post 131 may be covered by the insulating film 141. The insulating film 141 can also be formed on a portion of the surface of the pad portion 111 in addition to the conductive post 131, thereby allowing the insulating film 141 to be interposed between the pad portion 111 and the protective layer 121. By forming the insulating film 141 on the surface of the pad portion 111, the pad portion 111 can also be effectively protected. When the insulating film 141 is formed on both the surface of the conductive post 131 and the surface of the pad portion 111, the structural stability of the printed circuit board 100 can be greatly improved, and in such a case, it can be said that the conductive post 131 does not necessarily need to have a configuration that includes a protrusion P.

[0038] Furthermore, the insulating film 141 can also be formed on the surface of the conductor layer 112, thus protecting the conductor layer 112 as well. Conventionally, in order to improve adhesion with the protective layer 121, surface treatment was often performed by partially etching the surfaces of conductive posts 131, pad portions 111, conductor layer 112, etc., to increase their roughness, and then the protective layer 121 was formed. However, this may increase signal loss and degrade electrical characteristics. In this embodiment, by employing the insulating film 141, surface treatment of conductive posts 131, pad portions 111, conductor layer 112, etc., is not required, and even in such cases, high adhesion with the protective layer 121 can be obtained. Moreover, the insulating film 141 can also be formed on the upper surface of the insulating layer 101. In this case, as shown in the illustrated configuration, the insulating film 141 can extend to the surface of the pad portion 111 and the insulating layer 101 to form an overall integrated structure. As can be seen from the process described later, such an integrated structure can be realized by forming the insulating film 141 overall on the surface of the insulating layer 101, pad portion 111, conductor layer 112, conductive post 131, etc. In this case, the insulating film 141 can have a shape that follows the surface of the conductive post 131, pad portion 111, and insulating layer 101. However, in Figure 3, the insulating film 141 forms an overall integrated structure on the surface of the pad portion 111, conductor layer 112, and conductive post 131, but the insulating film 141 may be formed only on the surface of the conductive post 131. Alternatively, the insulating film 141 may be formed only on the surface of the conductive post 131 and the pad portion 111.

[0039] Considering the functions described above, it may be appropriate for the insulating film 141 to be thin while maintaining high insulating properties. The insulating film 141 can be coated on a portion of the surface of the conductive post 131. In this case, the insulating film 141 can be an atomic layer deposition layer. As a more specific example, the insulating film 141 may contain Al2O3. Alternatively, the insulating film 141 may be a surface oxide layer of the conductive post 131.

[0040] Referring to Figures 5-10, an example of a method for manufacturing a printed circuit board will be described. The following description will focus on the method for forming the insulating film 141, but for other components, the usual knowledge of manufacturing printed circuit boards can be utilized. First, pad portions 111, a conductor layer 112, and conductive posts 131 are formed on the insulating layer 101 (Figure 5). Then, the insulating film 141 is formed to cover the pad portions 111, the conductor layer 112, and the conductive posts 131 overall (Figure 6). As an example of the process, the insulating film 141 can be formed by an atomic layer deposition process. However, the insulating film 141 can be formed using other deposition processes. In this case, the insulating film 141 can be formed in a shape that follows the surface of the pad portions 111, the conductor layer 112, the conductive posts 131, etc. As described above, surface treatment to increase the roughness of the pad portions 111, the conductor layer 112, and the conductive posts 131 does not need to be performed before the formation of the insulating film 141, thereby reducing signal loss due to the reduction in the size of the circuit pattern.

[0041] Next, a protective layer 121 is formed on the insulating film 141 (Figure 7), where the protective layer 121 can be formed to a thickness that covers the upper surface of the conductive post 131. Subsequently, a portion of the protective layer 121 is removed to reduce its thickness so that at least a portion of the conductive post 131 protrudes to the outside (Figure 8). This removal of the protective layer 121 can utilize a process used in photolithography processes in the art. Subsequently, a mask 200 is formed to expose the upper surface of the conductive post 131 (Figure 9). The mask 200 can be, for example, a DFR (Dry Film Resist), which can expose the area where the conductive post 131 is formed through exposure and development processes. Subsequently, the insulating film 141 formed on the upper surface of the conductive post 131 is removed (Figure 10), and dry etching, wet etching, etc., known in the art can be used. Subsequently, the mask 200 is removed to obtain a printed circuit board 100 in the form shown in Figure 3.

[0042] In the other steps, the same configuration as in the method for manufacturing a printed circuit board according to one example or another example can also be applied to the printed circuit board according to yet another example; therefore, redundant explanations regarding this will be omitted.

[0043] A modified embodiment will be described with reference to Figure 11. In the modified form of Figure 11, a conductive cap layer 132 is further included to more effectively protect the conductive post 131 and improve electrical connectivity. Specifically, the conductive cap layer 132 is placed on the conductive post 131 and electrically connected to the conductive post 131. In this case, due to the presence of the insulating film 141, the conductive cap layer 132 can be formed in a manner that does not cover the sides of the conductive post 131. Furthermore, as in the illustrated embodiment, the conductive cap layer 132 can also be formed in a manner that does not cover the sides of the insulating film 141.

[0044] In this disclosure, "on a cross-section" can mean the cross-sectional shape when the object is cut vertically, or the cross-sectional shape when the object is viewed from the side. Furthermore, "on a plane" can mean the shape when the object is cut horizontally, or the planar shape when the object is viewed from the top or bottom.

[0045] In this disclosure, terms such as "upper," "upper," and "top surface" are used for convenience to refer to the direction toward the surface on which electronic components can be mounted, based on the cross-section of the drawing, while terms such as "lower," "lower," and "bottom surface" are used in the opposite direction. However, these are merely definitions of directions for explanatory purposes, and it goes without saying that the scope of the claims is not particularly limited by such descriptions of directions.

[0046] In this disclosure, "connected" refers not only to directly connected components but also to indirectly connected components, such as those connected through an adhesive layer. Furthermore, "electrically connected" refers to both physically connected and non-connected components. The terms "first," "second," etc., are used to distinguish one component from another and do not limit the order and / or importance of the components. In some cases, without exceeding the scope of the rights, the first component may be named as the second component, and similarly, the second component may be named as the first component.

[0047] The expression "example" as used in this disclosure does not mean that each embodiment is identical to another, but is provided to highlight and illustrate the unique and distinct features of each embodiment. However, the examples presented above do not preclude their realization in combination with features of other examples. For example, even if a matter described in one example is not described in another example, it can be understood as a description related to the other example, unless there is a contradictory or inconsistent description of that matter in the other example.

[0048] The terms used in this disclosure are for illustrative purposes only and are not intended to limit the disclosure. Where otherwise clearly, singular expressions include plural expressions. [Explanation of symbols]

[0049] 1000:Electronic equipment 1010: Mainboard 1020: Chip-related components 1030: Network-related components 1040: Other parts 1050: Camera 1060: Antenna 1070: Display 1080: Battery 1090: Signal line 1100: Smartphone 1110: Motherboard 1120: Parts 1121: Parts Package 1130: Camera module 1140: Speaker 101: Insulating layer 111: Pad section 112: Conductor layer 121:Protective layer 131: Conductive Post 132: Conductive cap layer 141: Insulating film

Claims

1. Insulating layer and, A pad portion disposed on the insulating layer, A protective layer disposed on the insulating layer and the pad portion, A conductive post is positioned on the pad portion and protrudes outward from the protective layer, An insulating film formed on a part of the surface of the conductive post, Printed circuit boards, including those mentioned above.

2. The printed circuit board according to claim 1, wherein at least a portion of the insulating film is interposed between the conductive post and the protective layer.

3. The printed circuit board according to claim 1, wherein the insulating film is in contact with the conductive post and the protective layer.

4. The printed circuit board according to claim 1, wherein the insulating film is formed on at least a portion of the side surface of the conductive post that is not covered by the protective layer.

5. The printed circuit board according to claim 1, wherein at least a portion of the upper surface of the conductive post is exposed and not covered by the insulating film.

6. The printed circuit board according to claim 1, wherein the insulating film is also formed on the surface of the pad portion.

7. The present invention further includes a conductive layer disposed on the insulating layer, The printed circuit board according to claim 1, wherein the insulating film is also formed on the surface of the conductive layer.

8. The printed circuit board according to claim 1, wherein the insulating film is also formed on the upper surface of the insulating layer.

9. The printed circuit board according to claim 1, wherein the insulating film extends to the surface of the pad portion and the insulating layer, forming an overall integrated structure.

10. The printed circuit board according to claim 9, wherein the insulating film has a shape that conforms to the surface of the conductive post, the pad portion, and the insulating layer.

11. The printed circuit board according to claim 1, wherein the insulating film is an atomic layer deposited layer.

12. The aforementioned insulating film is Al ２ O ３ A printed circuit board according to claim 1, including the above.

13. The printed circuit board according to claim 1, further comprising a conductive cap layer disposed on the conductive post and electrically connected to the conductive post.

14. The printed circuit board according to claim 13, wherein the conductive cap layer is formed in an area that does not cover the side surface of the conductive post.

15. The printed circuit board according to claim 13, wherein the conductive cap layer is formed in an area that does not cover the side surface of the insulating film.

16. Insulating layer and, A pad portion disposed on the insulating layer, A protective layer disposed on the insulating layer and the pad portion, A conductive post is placed on the aforementioned pad portion, An insulating film formed on a part of the surface of the pad portion and the conductive post, Printed circuit boards, including those mentioned above.

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