Printed circuit board and manufacturing method thereof

Abstract

The invention provides a printed circuit board and a method of manufacturing the same. The printed circuit board includes: a first insulating layer; a pad portion on the first insulating layer; a connection layer on the pad portion and including a central portion and an extension portion extending from a bottom portion of the central portion toward an edge of a top surface of the pad portion; and a second insulating layer disposed on the first insulating layer and covering a portion of the pad portion and a portion of the connection layer, in which the extension portion of the connection layer may be located within a groove portion, the groove portion being a space formed between the second insulating layer and the pad portion, and the second insulating layer being disposed on the first insulating layer and covering a portion of the pad portion and a portion of the connection layer. And the upper surface of the extension part of the connecting layer can be covered with the second insulating layer.

Description

Technical Field

[0001] The present disclosure relates to a printed circuit board and a method for manufacturing the same. Background Art

[0002] As electronic devices (including mobile phones) in the information technology (IT) field become smaller, the size of metal pillars formed on a printed circuit board on which electronic components are mounted is also getting smaller.

[0003] As the size of the metal pillars on the printed circuit board decreases, the metal pillars may be separated from and lost on the printed circuit board. Summary of the Invention

[0004] The present disclosure provides a printed circuit board and a method for manufacturing the same that can prevent a pad portion from being separated from and lost on the printed circuit board.

[0005] However, the problems to be solved by the present disclosure are not limited to the above problems, and various extensions can be made within the scope of the technical idea included in the present disclosure.

[0006] According to some embodiments, a printed circuit board may include: a first insulating layer; a pad portion located on the first insulating layer; a connection layer located on the pad portion and including a central portion and an extension portion extending from a bottom surface of the central portion toward a top surface of the pad portion; and a second insulating layer provided on the first insulating layer and covering a part of the pad portion and a part of the connection layer, wherein the extension portion of the connection layer may be located within a groove portion, the groove portion being a space formed between the second insulating layer and the pad portion, and an upper surface of the extension portion of the connection layer may be covered with the second insulating layer.

[0007] The groove portion may be located on a lower surface of the second insulating layer above the pad portion and on the top surface of the pad portion.

[0008] A lower surface of the extension portion of the connection layer may be in contact with the pad portion.

[0009] The central portion of the connection layer may protrude above the second insulating layer.

[0010] The connection layer may further include a convex portion extending downward from the central portion and the extension portion.

[0011] The pad portion may include a recess in an upper surface of the pad portion.

[0012] The convex portion of the connection layer may be located within the recess of the pad portion.

[0013] The convex portion of the connection layer may be in contact with the pad portion.

[0014] According to some embodiments, a method of manufacturing a printed circuit board may include: forming a pad portion on a first insulating layer; stacking a photosensitive film on the pad portion and the first insulating layer; forming a hole in the photosensitive film; forming a groove portion extending from the bottom of the hole in the photosensitive film; and forming a metal layer in the hole and the groove portion to form a connection layer, the connection layer including a central portion located in the hole and an extension portion located in the groove portion.

[0015] The manufacturing method may further include: removing the photosensitive film; and stacking a second insulating layer on the pad portion, the connection layer, and the first insulating layer.

[0016] The manufacturing method may further include removing a part of the second insulating layer such that the central portion of the connection layer protrudes above the second insulating layer.

[0017] The groove portion may be formed on the lower surface of the photosensitive film located above the pad portion.

[0018] The lower surface of the extension portion of the connection layer may be formed on the pad portion to contact the pad portion.

[0019] The manufacturing method may further include removing a part of the upper surface of the pad portion that overlaps with the hole and the groove portion of the photosensitive film to form a recess in the upper surface of the pad portion.

[0020] The step of forming the connection layer may further include forming a convex portion extending downward from the central portion and the extension portion.

[0021] The convex portion of the connection layer may be formed in the recess of the pad portion.

[0022] The convex portion of the connection layer may be formed on the pad portion to contact the pad portion.

[0023] According to the present disclosure, a printed circuit board and a method of manufacturing the same capable of preventing a pad portion from being separated from and lost from the printed circuit board may be provided.

[0024] However, it is easily understandable that the effects of the present disclosure are not limited to the above effects, and various extensions can be made without departing from the spirit and scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic cross-sectional view of a printed circuit board according to an embodiment.

[0026] Figures 2 to 5 is a schematic cross-sectional view showing a method of manufacturing a printed circuit board according to an embodiment.

[0027] Figure 6 is a schematic cross-sectional view of a printed circuit board according to another embodiment.

[0028] Figures 7 to 10 is a schematic cross-sectional view showing a method of manufacturing a printed circuit board according to another embodiment. Detailed Description of the Embodiments

[0029] Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present disclosure pertains can easily implement the present disclosure. However, the present disclosure can be implemented in various different forms and is not limited to the embodiments provided herein.

[0030] To clearly describe the present disclosure, parts irrelevant to the description will be omitted, and throughout the specification, the same or similar components will be denoted by the same or similar reference numerals.

[0031] In addition, it should be understood that the accompanying drawings are provided only to facilitate the understanding of the embodiments of the present disclosure, and the spirit of the present disclosure is not limited by the drawings. However, the present disclosure includes all variations, equivalents, and alternatives included within the spirit and scope of the present disclosure.

[0032] In addition, for ease of description, the dimensions (such as thickness) of each component shown in the drawings are arbitrarily represented, and the present disclosure is not necessarily limited to the dimensions (such as thickness) shown. In the drawings, the dimensions of layers, films, panels, regions, etc. are exaggerated for clarity. In addition, in the drawings, the dimensions of some layers and regions have been exaggerated for ease of explanation.

[0033] In addition, it will be understood that when an element such as a layer, film, region, or plate is referred to as being "on" another element, it can be "directly on" the other element, or there can also be an intermediate element therebetween. In contrast, when an element is referred to as being "directly on" another element, there is no intermediate element therebetween. In addition, when an element is referred to as being "on" a reference element, it can be located above or below the reference element and does not necessarily have to be located above the reference element in the direction opposite to the direction of gravity.

[0034] In addition, unless explicitly described to the contrary, the words "comprising," "including," and "having" will be understood to imply including the stated elements without excluding any other elements.

[0035] In addition, throughout the specification, the word "plan view" refers to a view when an object is observed from the top, and the word "cross-sectional view" refers to a view of a cross-section taken vertically when an object is observed from the side.

[0036] In addition, throughout the specification, the term "connected" not only means that two or more elements are directly connected, but also means that two or more elements are indirectly connected through another element, means that two or more elements are physically and / or electrically connected, or means that two or more elements are integrally formed, although they are referred to by different names according to their positions or functions.

[0037] Hereinafter, various embodiments and modifications will be described in detail with reference to the accompanying drawings.

[0038] will be described with reference to Figure 1 a printed circuit board according to some embodiments. Figure 1 is a schematic cross-sectional view of a printed circuit board according to some embodiments of the present disclosure.

[0039] Referring to Figure 1 , the printed circuit board according to the present embodiment may include: a first insulating layer SUB; a pad portion ML located on the first insulating layer SUB; a connection layer SB located on the pad portion ML; and a second insulating layer CL provided on the first insulating layer SUB and covering a part of the pad portion ML and a part of the connection layer SB.

[0040] The second insulating layer CL may have a groove portion CV located on the pad portion ML, and the groove portion CV is a space formed between the second insulating layer CL and the pad portion ML. The groove portion CV may be formed on the lower surface of the second insulating layer CL located above the pad portion ML, and may extend toward the edge of the pad portion ML.

[0041] The second insulating layer CL may include a solder resist, but the present embodiment is not limited thereto.

[0042] The connection layer SB may include: a central portion SBP protruding above the second insulating layer CL; and an extension portion SBW extending laterally from the central portion SBP.

[0043] The central portion SBP of the connection layer SB may have a column shape, may protrude upward from the upper surface of the second insulating layer CL, and may be connected to an external device.

[0044] The connection layer SB may be in contact with the pad portion ML to electrically connect the printed circuit board to an external device.

[0045] The extension portion SBW of the connection layer SB may extend laterally from the lower portion of the central portion SBP and may be located within the groove portion CV of the second insulating layer CL. The upper surface of the extension portion SBW of the connection layer SB may be covered with the second insulating layer CL, and the lower surface of the extension portion SBW of the connection layer SB may be in contact with the pad portion ML.

[0046] Although not shown in Figure 1Although shown in [figure], the pad portion ML can be connected to an additional wiring layer located below or buried in the first insulating layer SUB through vias formed in the first insulating layer SUB.

[0047] The printed circuit board can be connected to an external device through a connection layer SB including a central portion SBP protruding above the second insulating layer CL. Thus, the printed circuit board can be connected to the external device with a cross-section of the central portion SBP of the connection layer SB smaller than that of the pad portion ML.

[0048] According to this embodiment, the extension portion SBW of the connection layer SB can be located in a groove portion CV formed between the second insulating layer CL and the pad portion ML, such that the extension portion SBW of the connection layer SB can be covered with the second insulating layer CL. Therefore, compared with the case where the connection layer SB does not include the extension portion SBW and is only composed of the central portion SBP, it is possible to prevent the connection layer SB from being lost from the printed circuit board due to an external force or load applied from the outside when the connection layer SB contacts the external device.

[0049] According to some embodiments, the lower surface of the extension portion SBW of the connection layer SB can contact the pad portion ML. Therefore, compared with a structure where the connection layer SB does not include the extension portion SBW and is only composed of the central portion SBP, the contact area between the connection layer SB and the pad portion ML can be relatively large. Therefore, by reducing the shear stress between the pad portion ML and the connection layer SB, the adhesion between the pad portion ML and the connection layer SB can be increased, and by reducing the contact resistance between the pad portion ML and the connection layer SB, the loss of electrical signals can be reduced and the resistance can be lowered.

[0050] Reference will be made to Figures 2 to 5 and in conjunction with Figure 1 to describe a method of manufacturing a printed circuit board according to some embodiments. Figures 2 to 5 is a schematic cross-sectional view showing a method of manufacturing a printed circuit board according to some embodiments.

[0051] Referring to Figure 2 , a pad portion ML can be formed on the first insulating layer SUB, a photosensitive film DF can be stacked on the pad portion ML and the first insulating layer SUB, and holes HL of the photosensitive film DF overlapping the pad portion ML can be formed.

[0052] The holes HL of the photosensitive film DF can be formed in a portion where the columnar central portion SBP of the connection layer SB is to be formed.

[0053] The photosensitive film DF can be photosensitive and can be a dry film, but this embodiment is not limited thereto.

[0054] Referring to Figure 3, an extended hole HLW extending toward the edge of the pad portion ML can be formed on the lower surface of the hole HL of the photosensitive film DF. The extended hole HLW of the photosensitive film DF can be formed by the following method: etching a part of the lower surface of the photosensitive film DF located above the pad portion ML by controlling the etching conditions. The extended hole HLW of the photosensitive film DF can correspond to the groove portion CV of the second insulating layer CL.

[0055] Refer to Figure 4 , a metal layer can be formed in the hole HL and the extended hole HLW of the photosensitive film DF to form a central portion SBP of the connection layer SB located in the hole HL of the photosensitive film DF and an extended portion SBW of the connection layer SB located in the extended hole HLW. The metal layer can be formed by means such as electroplating, but this embodiment is not limited thereto.

[0056] Refer to Figure 5 , the photosensitive film DF can be removed.

[0057] Thereafter, the printed circuit board shown in Figure 1 can be formed by the following method: stacking the second insulating layer CL on the pad portion ML, the connection layer SB, and the first insulating layer SUB, and reducing the height of the second insulating layer CL to expose the central portion SBP of the connection layer SB, or removing a part of the second insulating layer CL to make the central portion SBP of the connection layer SB protrude above the second insulating layer CL.

[0058] Reference will be made to Figure 6 to describe a printed circuit board according to another embodiment. Figure 6 is a schematic cross-sectional view of a printed circuit board according to another embodiment.

[0059] Refer to Figure 6 , the printed circuit board according to this embodiment is similar to the printed circuit board of the embodiment described with reference to Figure 1 before. The detailed description of the same components can be omitted.

[0060] Refer to Figure 6 , the printed circuit board according to this embodiment can include: a first insulating layer SUB; a pad portion ML located on the first insulating layer SUB; a connection layer SB located on the pad portion ML; and a second insulating layer CL provided on the first insulating layer SUB and covering a part of the pad portion ML and a part of the connection layer SB.

[0061] A groove portion CV located on the pad portion ML and extending toward the edge of the pad portion ML can be formed on the lower surface of the second insulating layer CL located above the pad portion ML.

[0062] The connection layer SB can include: a central portion SBP protruding above the second insulating layer CL; and an extended portion SBW extending laterally from the bottom of the central portion SBP.

[0063] Unlike the printed circuit board according to the embodiment of Figure 1 , the printed circuit board according to the present embodiment shown in Figure 6 may include a recess MLC formed on the upper surface of the pad portion ML, and the connection layer SB may further include a protrusion SBC located within the recess MLC of the pad portion ML.

[0064] The central portion SBP of the connection layer SB may have a column shape, may protrude upward from the upper surface of the second insulating layer CL, and may be connected to an external device.

[0065] The extension portion SBW of the connection layer SB may extend laterally from the lower portion of the central portion SBP and may be located within the groove portion CV of the second insulating layer CL.

[0066] The protrusion SBC of the connection layer SB may extend downward from the extension portion SBW and the lower portion of the central portion SBP of the connection layer SB into the recess MLC of the pad portion ML. The protrusion SBC of the connection layer SB may be in contact with the pad portion ML.

[0067] The printed circuit board may be connected to an external device through the connection layer SB including the central portion SBP protruding above the second insulating layer CL. Therefore, the printed circuit board may be connected to the external device with a cross-section of the central portion SBP of the connection layer SB smaller than the cross-section of the pad portion ML.

[0068] According to the present embodiment, the extension portion SBW of the connection layer SB may be located within the groove portion CV formed inside the second insulating layer CL, and thus, the extension portion SBW of the connection layer SB may be covered with the second insulating layer CL. Therefore, compared with a structure in which the connection layer SB does not include the extension portion SBW and is composed only of the central portion SBP, it is possible to prevent the connection layer SB from being lost from the printed circuit board due to an external force or load applied from the outside when the connection layer SB comes into contact with an external device.

[0069] According to the present embodiment, the protrusion SBC extending from the extension portion SBW and the lower portion of the central portion SBP of the connection layer SB is located within the recess MLC of the pad portion ML, and thus the contact area between the connection layer SB and the pad portion ML may be relatively large. Therefore, by reducing the shear stress between the pad portion ML and the connection layer SB, the adhesion between the pad portion ML and the connection layer SB may be increased, and by reducing the contact resistance between the pad portion ML and the connection layer SB, the loss of electrical signals may be reduced and the resistance may be lowered.

[0070] Many features of the printed circuit board according to the embodiment described previously with reference to Figure 1 may be applicable to the printed circuit board according to the present embodiment.

[0071] Reference will be made to Figures 7 to 10 and in combination withFigure 6 Describe a method of manufacturing a printed circuit board according to some embodiments. Figures 7 to 10 is a schematic cross-sectional view showing a method of manufacturing a printed circuit board according to another embodiment.

[0072] Referring to Figure 7 , a pad portion ML can be formed on a first insulating layer SUB, a photosensitive film DF can be stacked on the pad portion ML and the first insulating layer SUB, and a hole HL of the photosensitive film DF that overlaps with the pad portion ML can be formed.

[0073] The hole HL of the photosensitive film DF can be formed in a part of a columnar central portion SBP where a connection layer SB is to be formed.

[0074] The photosensitive film DF can be photosensitive and can be a dry film, but this embodiment is not limited thereto.

[0075] Referring to Figure 8 , an extension hole HLW extending toward an edge of the pad portion ML can be formed on a lower surface of the hole HL of the photosensitive film DF, and a recess MLC of the pad portion ML can be formed by etching a part of an upper surface of the pad portion ML. The extension hole HLW of the photosensitive film DF can be formed by etching a part of a lower surface of the photosensitive film DF located above the pad portion ML by controlling etching conditions. The recess MLC of the pad portion ML can be formed by etching an upper surface of the pad portion ML exposed through the hole HL and the extension hole HLW of the photosensitive film DF by controlling etching conditions.

[0076] Referring to Figure 9 , a metal layer is formed in the hole HL and the extension hole HLW of the photosensitive film DF and the recess MLC of the pad portion ML, so that a central portion SBP of the connection layer SB located in the hole HL of the photosensitive film DF, an extension portion SBW of the connection layer SB located in the extension hole HLW, and a convex portion SBC of the connection layer SB located in the recess MLC of the pad portion ML are formed. In addition, the convex portion SBC of the connection layer SB can be formed on the pad portion ML to contact the pad portion ML.

[0077] Referring to Figure 10 , the photosensitive film DF can be etched to remove it. Thereafter, the printed circuit board shown in Figure 6 can be formed by stacking a second insulating layer CL on the pad portion ML, the connection layer SB, and the first insulating layer SUB, and reducing the height of the second insulating layer CL to expose the central portion SBP of the connection layer SB, or removing a part of the second insulating layer CL to make the central portion SBP of the connection layer SB protrude above the second insulating layer CL.

[0078] According to what was previously referred to Figures 2 to 5Many features of the method for manufacturing a printed circuit board according to the described embodiments are applicable to the method for manufacturing a printed circuit board according to the present embodiment.

[0079] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited thereto, and various modifications can be made within the scope of the present disclosure, and various modifications naturally also fall within the scope of the present disclosure.

[0080] <Description of Reference Numerals> ML: Pad portion MLC: Recessed portion SB: Connection layer SBP: Central portion SBW: Extension portion SBC: Protruding portion SUB: First insulating layer CL: Second insulating layer CV: Groove portion.

Claims

1. A printed circuit board, comprising: a first insulating layer; A pad portion, located on the first insulating layer; a connection layer located on the pad portion and including a central portion and an extending portion extending from a bottom of the central portion toward an edge of a top surface of the pad portion; as well as a second insulating layer disposed on the first insulating layer and covering a portion of the pad portion and a portion of the connection layer, The extending portion of the connection layer is located in a groove portion, which is a space formed between the second insulating layer and the pad portion, and an upper surface of the extending portion of the connection layer is covered with the second insulating layer.

2. The printed circuit board according to claim 1, wherein: The groove portion is located on a lower surface of the second insulating layer above the pad portion and on the top surface of the pad portion.

3. The printed circuit board according to claim 2, wherein: A lower surface of the extending portion of the connection layer contacts the pad portion.

4. The printed circuit board according to claim 3, wherein: The central portion of the connection layer protrudes above the second insulating layer.

5. The printed circuit board according to claim 2, wherein: The connection layer further includes a convex portion extending downward from the central portion and the extending portion.

6. The printed circuit board according to claim 5, wherein: The pad portion includes a recessed portion in an upper surface of the pad portion.

7. The printed circuit board according to claim 6, wherein: The convex portion of the connection layer is located within the concave portion of the pad portion.

8. The printed circuit board according to claim 7, wherein: The protrusion of the connection layer is in contact with the pad portion.

9. The printed circuit board according to claim 8, wherein: The central portion of the connection layer protrudes above the second insulating layer.

10. The printed circuit board according to claim 1, wherein The central portion of the connection layer protrudes above the second insulating layer.

11. A method for manufacturing a printed circuit board, the method comprising: forming a pad portion on the first insulating layer; stacking a photosensitive film on the pad portion and the first insulating layer; forming holes in the photosensitive film; forming a groove portion extending from a bottom of the hole in the photosensitive film; as well as A metal layer is formed in the hole and the groove portion to form a connection layer, the connection layer including a central portion located in the hole and an extension portion located in the groove portion.

12. The manufacturing method according to claim 11, further comprising: removing the photosensitive film; as well as A second insulating layer is stacked on the pad portion, the connection layer, and the first insulating layer.

13. The manufacturing method according to claim 12, further comprising: A portion of the second insulating layer is removed to allow the central portion of the connection layer to protrude above the second insulating layer.

14. The manufacturing method according to claim 11, wherein: The groove portion is formed on a lower surface of the photosensitive film above the pad portion.

15. The manufacturing method according to claim 14, wherein: A lower surface of the extending portion of the connection layer is formed on the pad portion to contact the pad portion.

16. The manufacturing method according to claim 11, further comprising: A portion of an upper surface of the pad portion overlapping the hole and the groove portion of the photosensitive film is removed to form a recessed portion in the upper surface of the pad portion.

17. The manufacturing method according to claim 16, wherein: The step of forming the connection layer further includes forming a convex portion extending downward from the central portion and the extending portion.

18. The manufacturing method according to claim 17, wherein: The convex portion of the connection layer is formed in the concave portion of the pad portion.

19. The manufacturing method according to claim 18, wherein: The convex portion of the connection layer is formed on the pad portion to be in contact with the pad portion.

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