HDI board

Abstract

The utility model discloses an HDI board, and relates to the technical field of circuit board design. The HDI plate comprises a substrate and a wiring layer group which are stacked, the HDI plate is provided with a laser hole group, the laser hole group is located in the wiring layer group, the central axis of each laser hole of the laser hole group extends along the thickness direction of the HDI plate, the hole length of each laser hole of the laser hole group is smaller than the thickness of the wiring layer group, and the thickness of the wiring layer group is smaller than the thickness of the substrate. And the first end of the laser hole group extends to one surface, deviating from the substrate, of the wiring layer group. According to the scheme, the problem that a laser hole of an existing HDI plate is prone to failure under the high-temperature and high-pressure conditions can be solved.

Description

Technical Field

[0001] This application belongs to the field of circuit board design technology, specifically relating to an HDI board. Background Technology

[0002] HDI (High Density Interconnector) boards are a type of printed circuit board that uses micro-blind via technology to achieve a high density of circuitry. Their electrical performance and signal accuracy are superior to ordinary PCBs. Furthermore, HDI boards offer better protection against radio frequency interference, electromagnetic interference, electrostatic discharge, and heat conduction.

[0003] Currently, HDI boards are the most widely used type of circuit board in many products, and the market demand is large. However, the manufacturing technology of HDI boards is more complex than that of conventional circuit boards, requiring more processes and monitoring during production. In practical applications, HDI boards need to undergo high-temperature and high-pressure testing. Under such conditions, the requirements for the high temperature resistance and high-pressure resistance of HDI boards are high. After being subjected to high temperature and high pressure, delamination of different material layers is usually inevitable, which leads to the failure of some laser holes on the HDI board. Utility Model Content

[0004] The purpose of this application is to provide an HDI board that can solve the problem that the laser holes of the current HDI board are prone to failure under high temperature and high pressure conditions.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] This application provides an HDI board, including stacked substrates and wiring layers.

[0007] The HDI board is provided with a laser hole group, which is located in the wiring layer group. The central axis of each laser hole in the laser hole group extends along the thickness direction of the HDI board, and the length of each laser hole in the laser hole group is less than the thickness of the wiring layer group. The first end of the laser hole group extends to the side of the wiring layer group away from the substrate.

[0008] In this embodiment, the HDI board is provided with a laser via group located in the wiring layer group. The central axis of each laser via in the laser via group extends along the thickness direction of the HDI board, and the length of each laser via in the laser via group is less than the thickness of the wiring layer group. The first end of the laser via group extends to the side of the wiring layer group away from the substrate, i.e., the laser via group is a blind via structure. When the HDI board is under high temperature and high pressure, compared with a single laser via, the laser via group in this solution can disperse the heat inside a single laser via, thereby reducing the expansion of the metal coating coated on the inner wall of the laser via, reducing the interaction force between the metal coating and the metal layer in the wiring layer group, and thus reducing the risk of splitting at the connection between the two, avoiding failure of a single laser via; furthermore, even if one laser via in the laser via group fails, other laser vias can still work to meet normal electrical connection requirements. Attached Figure Description

[0009] Figure 1 This is a top view of a portion of the structure of the HDI board disclosed in the embodiments of this application;

[0010] Figure 2 This is a cross-sectional view of a portion of the structure of the HDI board disclosed in the embodiments of this application.

[0011] Explanation of reference numerals in the attached figures:

[0012] 110 - Substrate, 120 - Adhesive layer, 130 - Metal layer, 131 - First metal layer, 132 - Second metal layer, 140 - Laser hole group, 140a - First laser hole group, 140b - Second laser hole group, 140c - Third laser hole group, 140d - Fourth laser hole group, 141 - Laser hole, 141a - First hole segment, 141b - Second hole segment, 150 - Pad. Detailed Implementation

[0013] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0014] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0015] The HDI board provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0016] like Figures 1 to 2 As shown, this application embodiment provides an HDI board, which includes a stacked substrate 110 and a wiring layer group. The HDI board is provided with a laser hole group 140, which is located in the wiring layer group. The central axis of each laser hole 141 in the laser hole group 140 extends along the thickness direction of the HDI board, and the hole length of each laser hole 141 in the laser hole group 140 is less than the thickness of the wiring layer group. The first end of the laser hole group 140 extends to the side of the wiring layer group away from the substrate 110, that is, the laser hole group 140 is a blind hole structure.

[0017] In this embodiment, when the HDI board is under high temperature and high pressure, the laser hole group 140 in this solution can disperse the heat within a single laser hole 141 compared to a single laser hole 141. This reduces the expansion of the metal coating on the inner wall of the laser hole 141, thereby reducing the interaction force between the metal coating and the metal layer in the wiring layer group, and thus reducing the risk of splitting at the connection point, preventing the failure of a single laser hole 141. Therefore, this embodiment can solve the problem that the laser holes 141 of the HDI board are prone to failure under high temperature and high pressure.

[0018] In addition, in the above embodiments, even if one of the laser holes 141 in the laser hole group 140 fails, other laser holes 141 can still work to meet normal electrical connection requirements.

[0019] In an optional embodiment, the wiring layer group includes an adhesive layer 120 and a metal layer 130, with the adhesive layer 120 positioned between the metal layer 130 and the substrate 110. Optionally, during the fabrication of the HDI board, the metal layer 130 can be etched to form a circuit pattern, thereby forming a wiring layer. Optionally, each metal layer 130 can be made of copper foil, which has good conductivity, ductility, and bending resistance. Optionally, the adhesive layer 120 can be an insulating structure to prevent short circuits between adjacent metal layers 130. Optionally, the adhesive layer 120 can be made of PP (Polypropylene), which consists of a semi-solid resin and glass fiber, with a wetting layer formed on its surface, allowing for better adhesion to adjacent metal layers 130.

[0020] The second end of the laser aperture group 140 extends through the adhesive layer 120 to the metal layer 130 and is electrically connected to the metal layer 130. That is, the substrate 110, adhesive layer 120, and metal layer 130 are stacked sequentially. When electronic components are arranged on the surface of the HDI board, the electronic components are electrically connected to the first end of the laser aperture group 140. At this time, the electronic components are electrically connected to the metal layer 130 through the laser aperture group 140, thereby transmitting electrical signals to the electronic components to ensure that they can function normally.

[0021] Optionally, the side of the wiring layer group facing away from the substrate 110 is formed by an adhesive layer 120. In this case, the adhesive layer 120 serves as an insulating or protective layer, which helps protect the metal layer (i.e., the wiring layer) inside the wiring layer group. Alternatively, the side of the wiring layer group facing away from the substrate 110 is formed by a metal layer 130, which allows some electronic components to be directly electrically connected to the metal layer. In other words, the choice between forming the side of the wiring layer group facing away from the substrate 110 with an adhesive layer 120 or with a metal layer 130 can be flexibly made according to actual needs.

[0022] In one optional embodiment, the laser aperture group 140 includes at least two laser apertures 141 arranged side-by-side in a direction perpendicular to the thickness direction of the HDI board. Optionally, during the fabrication of the laser aperture group 140, at least two interconnected connection holes can be first opened on the wiring layer, and then a metal coating is coated on the inner wall of each connection hole, with the metal coatings in adjacent connection holes connected to form the aforementioned laser aperture group 140. Optionally, adjacent laser apertures 141 are electrically conductive, i.e., each laser aperture 141 adopts the same network design; further optionally, adjacent connection holes can be tangential, and the metal coatings covering the surfaces of adjacent connection holes are electrically connected. When the HDI board is under high temperature and high pressure, the heat in adjacent laser apertures 141 can be diffused through the metal coating, which helps to improve the efficiency of heat dissipation in each laser aperture 141, thereby reducing the expansion of the metal coating on the inner wall of the laser aperture 141. Furthermore, in actual use, if some of the laser holes 141 in at least two laser holes 141 are damaged, the remaining laser holes 141 can still function to achieve the electrical connection performance of the laser hole group 140. Of course, during the fabrication of the laser hole group 140, the at least two connection holes opened on the wiring layer can also be spaced apart.

[0023] Optionally, the area of ​​the cross-section of each laser hole 141 (specifically, the cross-section of the laser hole 141 in the thickness direction of the HDI board) can remain unchanged; or, in other optional embodiments, each laser hole 141 includes a first hole segment 141a and a second hole segment 141b that are connected. The first hole segment 141a and the second hole segment 141b are coaxial. In the direction perpendicular to the thickness direction of the HDI board, the width of the first hole segment 141a is greater than the width of the second hole segment 141b, that is, the area of ​​the cross-section of the first hole segment 141a is greater than the area of ​​the cross-section of the second hole segment 141b, so that each laser hole 141 is a stepped blind hole. The first hole segment 141a is disposed in the layer of the wiring layer group that is farthest from the substrate 110, that is, the first hole segment 141a is disposed in the surface layer of the HDI board. The surface layer can be a metal layer 130, an adhesive layer 120, or a pad 150. This application embodiment does not impose specific limitations on this. The end of the second hole segment 141b away from the first hole segment 141a extends through the adhesive layer 120 to the metal layer 130.

[0024] The laser holes 141 included in the laser hole group 140 in the above scheme are all stepped blind holes, which have the characteristics of strengthening the mechanical strength of the circuit board and improving the stability of the circuit board, so that the HDI board is not easily deformed or damaged when subjected to external pressure or impact; in addition, it can also improve the connection density and reliability between the surface layer and adjacent layers of the HDI board.

[0025] It should be noted that during the fabrication of the laser hole group 140, the smoothness and flatness of the inner surface of each laser hole 141 must be ensured to reduce the connection resistance between adjacent layers and improve the reliability of the HDI board.

[0026] Optionally, each laser hole 141 can be a circular hole, a triangular hole, or a rectangular hole, and there is no specific limitation on this; further optionally, each laser hole 141 can be a circular hole, which not only facilitates hole making, but also facilitates electroplating of metal coating.

[0027] In an optional embodiment, the width of the first hole segment 141a is 0.25~0.35mm and the width of the second hole segment 141b is 0.1~0.15mm in the direction perpendicular to the thickness direction of the HDI board. If the widths of the first hole segment 141a and the second hole segment 141b are too small, it will increase the difficulty of drilling and make processing inconvenient; if the widths of the first hole segment 141a and the second hole segment 141b are too large, it will reduce the structural strength of the HDI board and occupy a large space, interfering with the wiring of the HDI board. Therefore, this solution sets the width of the first hole segment 141a to 0.25~0.35mm and the width of the second hole segment 141b to 0.1~0.15mm in the direction perpendicular to the thickness direction of the HDI board. This not only reduces the difficulty of drilling but also ensures the structural strength of the HDI board and reduces the impact on the wiring of the HDI board.

[0028] Optionally, the dimensions of adjacent laser holes 141 may not be equal. Specifically, the dimensions refer to the length, width, and height of the laser holes 141. That is, at least one of the length, width, and height of adjacent laser holes 141 may be different. In this case, differential settings need to be made during the manufacturing process of the laser hole group 140. Alternatively, in another optional embodiment, the dimensions of each laser hole 141 are equal, that is, the length, width, and height of each laser hole 141 are the same. This facilitates the processing and manufacturing of the laser hole group 140, thereby improving the manufacturing efficiency of the HDI board.

[0029] In one optional embodiment, the number of adhesive layers 120 and metal layers 130 is at least two. Each metal layer 130 and each adhesive layer 120 is alternately arranged sequentially along the thickness direction of the substrate 110. That is, the number of adhesive layers 120 and metal layers 130 disposed on one side of the substrate 110 is at least two, and each metal layer 130 and each adhesive layer 120 is alternately arranged sequentially along the thickness direction of the substrate 110. Each of the at least two metal layers 130 includes a first metal layer 131 and a second metal layer 132 spaced apart. The number of laser hole groups 140 is at least two groups. Each of the at least two laser hole groups 140 includes a first laser hole group 140a and a second laser hole group 140b spaced apart. The first end of the first laser hole group 140a and the first end of the second laser hole group 140b both extend to the side of the wiring layer group facing away from the substrate 110. The first end of a laser hole group 140a and the first end of a laser hole group 140b both extend to the surface layer of the HDI board, and the second end of the first laser hole group 140a and the second end of the second laser hole group 140b can both extend to the same metal layer 130; or, optionally, the second end of the first laser hole group 140a extends to the first metal layer 131, and the second end of the second laser hole group 140b extends to the second metal layer 132, that is, the hole length of each laser hole 141 of the first laser hole group 140a and the hole length of each laser hole 141 of the second laser hole group 140b are different, so that the first laser hole group 140a and the second laser hole group 140b are connected to different circuit layers respectively, and correspondingly, the first laser hole group 140a and the second laser hole group 140b are electrically connected to different electronic components respectively, thereby realizing the multifunctionality of the HDI board.

[0030] Optionally, the first laser aperture group 140a and the second laser aperture group 140b can be arranged in a centralized manner. This can further disperse the heat within the laser apertures 141 of the different laser aperture groups 140, thereby further reducing the expansion of the metal coating coated on the inner wall of each laser aperture 141, and further reducing the risk of splitting at the connection between the metal coating and the metal layer 130. Alternatively, the first laser aperture group 140a and the second laser aperture group 140b can be arranged in a dispersed manner. This not only facilitates the setting of each laser aperture group 140, but also facilitates the arrangement of electronic components.

[0031] Optionally, wiring layer groups may be provided only on one side of substrate 110, i.e., the HDI board is a single-sided board; or, in another optional embodiment, wiring layer groups are provided on both the first and second opposite sides of substrate 110 in the thickness direction of the HDI board, with the wiring layer group on the first side being the first wiring layer group and the wiring layer group on the second side being the second wiring layer group, i.e., the HDI board is a double-sided board. Optionally, both the first and second wiring layer groups include at least two adhesive layers 120 and at least two metal layers 130. The adhesive layers 120 and metal layers 130 on both opposite sides of substrate 110 are alternately arranged sequentially along the thickness direction of substrate 110. Optionally, the first and second wiring layer groups on both opposite sides of substrate 110 can be electrically connected through vias to transmit electrical signals.

[0032] Optionally, the number of laser via groups 140 is at least two, including a third laser via group 140c and a fourth laser via group 140d. The third laser via group 140c is disposed in the first wiring layer group, and its first end extends to the side of the first wiring layer group opposite to the substrate 110. The fourth laser via group 140d is disposed in the second wiring layer group, and its first end extends to the side of the second wiring layer group opposite to the substrate 110. The HDI board in this solution is a double-sided board, which allows for the arrangement of more circuits, thereby connecting more electronic components, which helps to improve the utilization rate of the HDI board.

[0033] In another optional embodiment, a pad 150 is provided on the side of the wiring layer group facing away from the substrate 110, and a laser via group 140 is located on the pad 150, with the first end of the laser via group 140 extending to the side of the pad 150 facing away from the substrate 110. In this solution, the laser via group 140 is disposed on the pad 150. When electronic components are placed on the pad 150, the electronic components are directly electrically connected to the laser via group 140, thus eliminating the need for additional wiring. In addition, more area can be reserved on the surface of the HDI board to accommodate more electronic components.

[0034] In another optional embodiment, a pad 150 is provided on the side of the wiring layer group facing away from the substrate 110, and the laser hole group 140 is staggered from the pad 150. This can avoid the risk of the pad 150 having a cold solder joint or the pad 150 detaching, thereby ensuring the connection reliability of the pad 150.

[0035] It should be noted that, during the manufacturing process of the HDI board disclosed in this application, the electroplating time of the metal coating on the inner wall of the laser hole must be strictly controlled to improve the quality of the laser hole group 140; and the aperture of each laser hole 141 must be strictly controlled; in addition, the adhesive layer 120 between the laser hole group 140 and the metal layer 130 (i.e., the bottom of the laser hole group 140) must be cleaned to improve the electrical connection performance between the laser hole group 140 and the metal layer 130.

[0036] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. An HDI board, characterized in that, Including a stacked substrate (110) and wiring layers, The HDI board is provided with a laser hole group (140), which is located in the wiring layer group. The central axis of each laser hole (141) in the laser hole group (140) extends along the thickness direction of the HDI board, and the length of each laser hole (141) in the laser hole group (140) is less than the thickness of the wiring layer group. The first end of the laser hole group (140) extends to the side of the wiring layer group away from the substrate (110).

2. The HDI board according to claim 1, characterized in that, The wiring layer assembly includes an adhesive layer (120) and a metal layer (130). The adhesive layer (120) is disposed between the metal layer (130) and the substrate (110). The second end of the laser hole assembly (140) extends through the adhesive layer (120) to the metal layer (130) and is electrically connected to the metal layer (130). The side of the wiring layer group facing away from the substrate (110) is formed by the adhesive layer (120); or, the side of the wiring layer group facing away from the substrate (110) is formed by the metal layer (130).

3. The HDI board according to claim 2, characterized in that, The laser hole group (140) includes at least two laser holes (141) arranged side by side in a direction perpendicular to the thickness direction of the HDI board, and adjacent laser holes (141) are electrically connected.

4. The HDI board according to claim 3, characterized in that, Each of the laser holes (141) includes a first hole segment (141a) and a second hole segment (141b) that are connected. The first hole segment (141a) and the second hole segment (141b) are coaxial. In a direction perpendicular to the thickness direction of the HDI board, the width of the first hole segment (141a) is greater than the width of the second hole segment (141b). The first hole segment (141a) is located in the wiring layer group that is furthest from the substrate (110). The end of the second hole segment (141b) away from the first hole segment (141a) extends through the adhesive layer (120) to the metal layer (130).

5. The HDI board according to claim 4, characterized in that, In the direction perpendicular to the thickness direction of the HDI board, the width of the first hole segment (141a) is 0.25~0.35mm, and the width of the second hole segment (141b) is 0.1~0.15mm.

6. The HDI board according to claim 3, characterized in that, All of the laser holes (141) are of the same size.

7. The HDI board according to claim 2, characterized in that, The number of adhesive layers (120) and metal layers (130) is at least two. Each metal layer (130) and each adhesive layer (120) are alternately arranged along the thickness direction of the substrate (110). Each of the at least two metal layers (130) includes a first metal layer (131) and a second metal layer (132) arranged at intervals. The number of laser hole groups (140) is at least two groups, and the at least two groups of laser hole groups (140) include a first laser hole group (140a) and a second laser hole group (140b) arranged at intervals. The first end of the first laser hole group (140a) and the first end of the second laser hole group (140b) both extend to the side of the wiring layer group away from the substrate (110). The second end of the first laser hole group (140a) extends to the first metal layer (131), and the second end of the second laser hole group (140b) extends to the second metal layer (132).

8. The HDI board according to claim 1, characterized in that, In the thickness direction of the HDI board, the wiring layer group is provided on both the first and second sides opposite to each other of the substrate (110). The wiring layer group located on the first side is the first wiring layer group, and the wiring layer group located on the second side is the second wiring layer group. The number of laser hole groups (140) is at least two groups, and the at least two groups of laser hole groups (140) include a third laser hole group (140c) and a fourth laser hole group (140d). The third laser hole group (140c) is disposed on the first wiring layer group, and the first end of the third laser hole group (140c) extends to the side of the first wiring layer group away from the substrate (110). The fourth laser hole group (140d) is disposed on the second wiring layer group, and the first end of the fourth laser hole group (140d) extends to the side of the second wiring layer group away from the substrate (110).

9. The HDI board according to claim 1, characterized in that, The wiring layer group has a pad (150) on the side away from the substrate (110), and the laser hole group (140) is located on the pad (150). The first end of the laser hole group (140) extends to the side of the pad (150) away from the substrate (110).

10. The HDI board according to claim 1, characterized in that, The wiring layer group has a pad (150) on the side facing away from the substrate (110), and the laser hole group (140) is staggered from the pad (150).

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