HDI printed circuit board with fine line buried holes

Abstract

The utility model discloses an HDI printed circuit board with a fine line buried hole, which relates to the technical field of circuit boards and comprises a board body, the board body comprises a first copper foil, a second copper foil, a third copper foil, a fourth copper foil, a fifth copper foil, a sixth copper foil and a dielectric layer, the first copper foil, the second copper foil, the third copper foil, the fourth copper foil, the fifth copper foil and the sixth copper foil are sequentially stacked from top to bottom, and the dielectric layer is arranged on the first copper foil, the second copper foil, the third copper foil, the fourth copper foil, the fifth copper foil and the sixth copper foil. The circuit board comprises a board body, blind holes are formed in the top and the bottom of the board body, a buried hole part is formed in the board body, and a second conductive material and a first conductive material are arranged in the blind holes and the buried hole part respectively. The contact area between the filled conductive material and the copper foil can be enlarged, so that the stability of each layer of circuit of the subsequent circuit board during electrical connection is ensured, the heat dissipation area of the whole circuit board is improved, and the circuit board with the buried hole is lower in heat productivity during working.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit boards, in particular to an HDI printed circuit board with fine circuit buried holes. Background Art

[0002] HDI circuit boards, or high-density interconnect boards, utilize micro-blind and buried via technology to achieve a relatively high circuit density. HDI boards have inner and outer layers of circuitry, interconnected through drilling and in-hole metallization. HDI boards are typically manufactured using a build-up method, with the higher the number of layers, the higher the board's technology.

[0003] During the HDI circuit board production process, laser drilling is used to create blind vias, while mechanical buried vias are also performed within the board. Traditionally, buried vias in circuit boards are often cylindrical holes. This type of buried via limits the contact area between the subsequent conductive material and the copper foil, impacting the stability of the circuit board during conduction and also impairing heat dissipation across the board. Therefore, there is an urgent need for an HDI printed circuit board with fine-line buried vias to address these issues. Utility Model Content

[0004] This utility model aims to address the shortcomings of the prior art by proposing an HDI printed circuit board with fine-line buried vias. Its advantage lies in that by configuring the buried vias in the circuit board as cylindrical sections with different inner diameters at the top and bottom, the contact area between the filled conductive material and the copper foil is expanded. This not only ensures the stability of subsequent electrical connections between the circuit boards' various layers, but also increases the heat dissipation area of the entire circuit board, resulting in lower heat generation during operation of the circuit board with these buried vias.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A fine-line buried-via HDI printed circuit board comprises a board body, the board body comprising a first copper foil, a second copper foil, a third copper foil, a fourth copper foil, a fifth copper foil, a sixth copper foil, and a dielectric layer, wherein the first copper foil, the second copper foil, the third copper foil, the fourth copper foil, the fifth copper foil, and the sixth copper foil are stacked in sequence from top to bottom, a blind hole is provided on the top and bottom of the board body, a buried hole portion is provided inside the board body, and a second conductive material and a first conductive material are provided inside the blind hole and the buried hole portion, respectively.

[0007] Through the above technical solution: the contact area between the filled conductive material and the copper foil can be expanded through the buried via portion, which not only ensures the stability of the subsequent electrical connection of each layer of the circuit board, but also increases the heat dissipation area of the entire circuit board, so that the circuit board with this type of buried via generates less heat during operation.

[0008] The utility model is further configured such that a through hole is provided on the top of the plate body, and the through hole passes through the plate body.

[0009] Through the above technical solution: the stability of the connection between the multiple layers in the board is guaranteed, and the subsequent installation of the board is also convenient.

[0010] The present invention is further configured such that the buried via portion passes through the second copper foil, the third copper foil, the fourth copper foil, and the fifth copper foil.

[0011] Through the above technical solution, it can be ensured that the lines between the second copper foil, the third copper foil, the fourth copper foil, and the fifth copper foil can be stably connected later through the conductive material.

[0012] The present invention is further configured such that the blind holes located on both sides of the plate body penetrate the first copper foil and the sixth copper foil respectively.

[0013] The above technical solution facilitates the stable connection of the circuits between the first copper foil and the second copper foil, and between the fifth copper foil and the sixth copper foil in the subsequent board.

[0014] The utility model is further configured such that the buried hole portion comprises a first cylindrical portion, an arcuate portion and a second cylindrical portion, and the arcuate portion is located in the middle of the first cylindrical portion and the second cylindrical portion.

[0015] Through the above technical solution, the debris generated during the mechanical drilling of the buried hole part can slide along the arc part to the second cylindrical part for discharge, avoiding the debris remaining in the buried hole part and affecting the subsequent filling of the conductive material.

[0016] The present invention is further configured such that the inner diameter of the first cylindrical portion is greater than the inner diameter of the second cylindrical portion.

[0017] Through the above technical solution: the contact area between the filled conductive material and the copper foil can be expanded, which not only ensures the stability of the subsequent electrical connection of each layer of the circuit board, but also increases the heat dissipation area of the entire circuit board, so that the circuit board with this type of buried via generates less heat during operation.

[0018] The utility model is further configured such that a matching groove is provided at one end of the first cylindrical portion, and the inner diameter of the matching groove is larger than that of the first cylindrical portion.

[0019] Through the above technical solution, the buried hole portion can be well enlarged, so that the conductive material subsequently filled into the buried hole portion and the copper foil are more tightly bonded.

[0020] The utility model is further configured such that a first oblique annular groove and a second oblique annular groove are respectively formed on the circumferential inner wall of the matching groove, and the cross sections of the first oblique annular groove and the second oblique annular groove are both right triangles.

[0021] The above technical solution can ensure that when the buried hole portion is subsequently metallized, the conductive material can be fully combined with the copper foil inside the board body, thereby improving the quality of the subsequent entire board body.

[0022] The beneficial effects of the utility model are:

[0023] In the present invention, by setting the buried via in the circuit board as a cylindrical portion with different inner diameters at the upper and lower parts, the contact area between the filled conductive material and the copper foil can be expanded, which not only ensures the stability of the subsequent electrical connection of the circuit boards of each layer, but also increases the heat dissipation area of the entire circuit board, so that the circuit board with this type of buried via generates less heat during operation.

[0024] In the present invention, since an arc portion is provided in the middle of the first cylindrical portion and the second cylindrical portion in the buried hole portion, the debris generated during the mechanical drilling of the buried hole portion can slide along the arc portion to the second cylindrical portion for discharge, thereby avoiding the debris remaining inside the buried hole portion and affecting the subsequent filling work of the conductive material.

[0025] In the present invention, by arranging a matching groove, a first oblique ring groove and a second oblique ring groove on the top of the first cylindrical portion, it can be ensured that when the buried hole portion is subsequently metallized, the conductive material can be fully combined with the copper foil inside the board body, thereby improving the subsequent quality of the entire board body. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the overall structure of an HDI printed circuit board with fine line buried vias proposed by the present invention;

[0027] Figure 2 This is a half-section view of an HDI printed circuit board with fine line buried holes proposed by the present invention;

[0028] Figure 3 This is a schematic cross-sectional plan view of the structure of an HDI printed circuit board with fine line buried vias proposed by the present invention;

[0029] Figure 4 This is a schematic cross-sectional view of a second embodiment of an HDI printed circuit board with fine line buried vias proposed by the present invention;

[0030] Figure 5 This utility model proposes a HDI printed circuit board with fine line buried holes Figure 4 Schematic diagram of the enlarged structure at point A in the middle.

[0031] In the figure: 1. Plate body; 1001. First copper foil; 1002. Dielectric layer; 1003. Second copper foil; 1004. Third copper foil; 1005. Fourth copper foil; 1006. Fifth copper foil; 1007. Sixth copper foil; 2. Blind hole; 3. Through hole; 4. First conductive material; 5. Second conductive material; 6. Buried hole portion; 6001. First cylindrical portion; 6002. Arc-shaped portion; 6003. Second cylindrical portion; 7. Fitting groove; 8. First oblique annular groove; 9. Second oblique annular groove. DETAILED DESCRIPTION

[0032] The technical solution of this patent is further described in detail below in conjunction with specific implementation methods.

[0033] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0034] In the description of this patent, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this patent and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on this patent.

[0035] In the description of this patent, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," and "set" should be understood in a broad sense. For example, they can refer to fixed connection or set, detachable connection or set, or integral connection or set. Those skilled in the art will understand the specific meanings of the above terms in this patent based on the specific circumstances. Example 1

[0036] Reference Figure 1-Figure 3A HDI printed circuit board with fine line buried vias includes a board body 1, which includes a first copper foil 1001, a second copper foil 1003, a third copper foil 1004, a fourth copper foil 1005, a fifth copper foil 1006, a sixth copper foil 1007, and a dielectric layer 1002. The first copper foil 1001, the second copper foil 1003, the third copper foil 1004, the fourth copper foil 1005, the fifth copper foil 1006, and the sixth copper foil 1007 are stacked in sequence from top to bottom. Blind vias 2 are formed at the top and bottom of the board body 1. A buried via portion 6 is formed inside the board body 1. A second conductive material 5 and a first conductive material 4 are respectively disposed inside the blind via 2 and the buried via portion 6. The buried via portion 6 can expand the contact area between the filled conductive material and the copper foil, thereby ensuring the stability of the subsequent electrical connection of the circuits of each layer of the circuit board and increasing the heat dissipation area of the entire circuit board, so that the circuit board with this type of buried vias generates less heat during operation.

[0037] In order to ensure the stability of the connection between the multiple layers in the board body 1 and to facilitate the subsequent installation of the board body 1, refer to Figure 2 A through hole 3 is provided on the top of the plate body 1 , and the through hole 3 passes through the plate body 1 .

[0038] For signal interconnection between the inner copper foils in the board body 1, refer to Figure 2-Figure 3 The buried via portion 6 passes through the second copper foil 1003, the third copper foil 1004, the fourth copper foil 1005, and the fifth copper foil 1006, which can ensure that the lines between the second copper foil 1003, the third copper foil 1004, the fourth copper foil 1005, and the fifth copper foil 1006 can be stably connected through conductive materials in the future.

[0039] In order to facilitate the stable connection of the circuits in the first copper foil 1001 and the second copper foil 1003, the fifth copper foil 1006 and the sixth copper foil 1007 in the subsequent board 1, refer to Figure 3 The blind holes 2 located on both sides of the board 1 pass through the first copper foil 1001 and the sixth copper foil 1007 respectively.

[0040] In order to avoid drilling debris remaining inside the buried hole part 6, refer to Figure 2-Figure 3 The buried hole portion 6 includes a first cylindrical portion 6001, an arc portion 6002 and a second cylindrical portion 6003. The arc portion 6002 is located in the middle of the first cylindrical portion 6001 and the second cylindrical portion 6003, so that the debris generated during the mechanical drilling process of the buried hole portion 6 can slide along the arc portion 6002 to the second cylindrical portion 6003 for discharge, thereby avoiding the debris remaining inside the buried hole portion 6 and affecting the subsequent filling work of the conductive material.

[0041] In order to improve the heat dissipation performance of the entire board 1, refer to Figure 2-Figure 3The inner diameter of the first cylindrical portion 6001 is larger than the inner diameter 6003 of the second cylindrical portion, which can expand the contact area between the filled conductive material and the copper foil, not only ensuring the stability of the subsequent electrical connection of each layer of the circuit board, but also increasing the heat dissipation area of the entire circuit board, so that the circuit board with this type of buried via generates less heat during operation. Example 2

[0042] Reference Figure 4-Figure 5 , an HDI printed circuit board with fine line buried vias. Compared with Example 1, this embodiment further includes a matching groove 7 provided at one end of the first cylindrical portion 6001. The inner diameter of the matching groove 7 is larger than that of the first cylindrical portion 6001, which can effectively expand the buried via portion 6, so that the conductive material subsequently filled into the buried via portion 6 is more tightly bonded to the copper foil.

[0043] In order to make the conductive material and the copper foil inside the board more firmly bonded, refer to Figure 4-Figure 5 The inner circumferential wall of the matching groove 7 is respectively provided with a first oblique annular groove 8 and a second oblique annular groove 9. The cross sections of the first oblique annular groove 8 and the second oblique annular groove 9 are both right triangles, which can ensure that when the buried hole portion 6 is metallized later, the conductive material can be fully combined with the copper foil inside the board body 1, thereby improving the quality of the entire board body 1 later.

[0044] Working principle: During the processing of the circuit board, the staff first stacked the second to fifth copper foils 1006 in sequence, and at the same time set a dielectric layer 1002 between the two groups of copper foils for isolation. After the four groups of copper foils were stacked and fixed, the staff obtained the buried hole part 6 by mechanical drilling. Since the first cylindrical part 6001 and the second cylindrical part 6003 in the buried hole part 6 are provided with an arc part 6002 in the middle, the debris generated during the mechanical drilling of the buried hole part 6 can slide along the arc part 6002 to the second cylindrical part 6003 for discharge, avoiding the debris remaining in the buried hole part 6 and affecting the subsequent filling of the conductive material. At the same time, the buried hole in the circuit board is set to have an inner diameter of the upper and lower parts. Different cylindrical parts can expand the contact area between the filled conductive material and the copper foil, which not only ensures the stability of the subsequent electrical connection of each layer of the circuit board, but also increases the heat dissipation area of the entire circuit board, so that the circuit board with this type of buried via generates less heat during operation. After the buried via portion 6 is opened, the staff will fix the first copper foil 1001 and the second copper foil 1003 together with the dielectric layer 1002 on one side of the second copper foil 1003 and the fifth copper foil 1006 respectively, thereby forming a whole circuit board. Subsequently, a blind hole 2 is opened on the surface of the first copper foil 1001 and the sixth copper foil 1007 through laser drilling equipment, thereby completing the production of the six-layer one-order HDI circuit board.

[0045] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A fine line buried hole HDI printed circuit board, comprising a board body (1), characterized in that: The board body (1) comprises a first copper foil (1001), a second copper foil (1003), a third copper foil (1004), a fourth copper foil (1005), a fifth copper foil (1006), a sixth copper foil (1007), and a dielectric layer (1002); the first copper foil (1001), the second copper foil (1003), the third copper foil (1004), the fourth copper foil (1005), the fifth copper foil (1006), and the sixth copper foil (1007) are stacked in sequence from top to bottom; a blind hole (2) is provided at the top and bottom of the board body (1); a buried hole portion (6) is provided inside the board body (1); a second conductive material (5) and a first conductive material (4) are provided inside the blind hole (2) and the buried hole portion (6), respectively.

2. The HDI printed circuit board with fine line buried vias according to claim 1, characterized in that: A through hole (3) is provided on the top of the plate body (1), and the through hole (3) passes through the plate body (1).

3. The HDI printed circuit board with fine line buried vias according to claim 1, characterized in that: The buried hole portion (6) passes through the second copper foil (1003), the third copper foil (1004), the fourth copper foil (1005), and the fifth copper foil (1006).

4. The HDI printed circuit board with fine line buried vias according to claim 1, characterized in that: The blind holes (2) located on both sides of the plate body (1) respectively penetrate the first copper foil (1001) and the sixth copper foil (1007).

5. The HDI printed circuit board with fine line buried vias according to claim 1, characterized in that: The buried hole portion (6) comprises a first cylindrical portion (6001), an arc-shaped portion (6002) and a second cylindrical portion (6003), wherein the arc-shaped portion (6002) is located in the middle of the first cylindrical portion (6001) and the second cylindrical portion (6003).

6. The HDI printed circuit board with fine line buried vias according to claim 5, characterized in that: The inner diameter of the first cylindrical portion (6001) is greater than the inner diameter (6003) of the second cylindrical portion.

7. The HDI printed circuit board with fine line buried vias according to claim 5, characterized in that: A matching groove (7) is provided at one end of the first cylindrical portion (6001), and the inner diameter of the matching groove (7) is larger than that of the first cylindrical portion (6001).

8. The HDI printed circuit board with fine line buried vias according to claim 7, characterized in that: A first oblique annular groove (8) and a second oblique annular groove (9) are respectively formed on the circumferential inner wall of the matching groove (7), and the cross sections of the first oblique annular groove (8) and the second oblique annular groove (9) are both right triangles.

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