Printed circuit board and drilling method thereof

Abstract

This invention discloses a printed circuit board and a drilling method thereof. The printed circuit board has at least two spaced-apart metallized semi-rings, each of which is electrically connected to the printed circuit board. Each pair of adjacent and corresponding metallized semi-rings is formed by dividing the same metallized via. With this structure, the invention can reduce the via spacing and the number of via press-fitting operations, achieving a high network density design for the printed circuit board while reducing the number of press-fitting operations and improving manufacturing efficiency.

Description

Technical Field

[0001] This invention applies to the technical field of printed circuit boards, and in particular to printed circuit boards and their drilling methods. Background Technology

[0002] PCB (Printed Circuit Board), also known as printed circuit board, is a widely used and important electronic component. It serves as the support for electronic components and the carrier for their electrical connections.

[0003] Currently, when designing multilayer PCBs, metallized vias are used to connect interlayer networks. These are typically achieved using mechanical drilling or laser drilling. Mechanically drilled vias can connect multiple conductive layers, but their precision is low, and a larger spacing is generally required between the vias to prevent short circuits between the via walls. Laser-drilled vias have smaller diameters and relatively smaller spacing between the via walls, but they generally only connect two conductive layers, making it impossible to connect multiple layers with a single via. To connect multiple layers, multiple lamination processes are required to accumulate the laser vias.

[0004] Therefore, in current drilling methods, there is a certain mutual limitation between the hole spacing and the number of times the hole is pressed. Summary of the Invention

[0005] This invention provides a printed circuit board and a drilling method thereof to solve the problem that there is a certain mutual limitation between the hole spacing and the number of times the hole is pressed in the drilling method in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides a printed circuit board, wherein at least two spaced metallized semi-rings are formed on the printed circuit board, and each metallized semi-ring is electrically connected to the printed circuit board; wherein each adjacent and corresponding at least two metallized semi-rings are formed by dividing the same metallized hole.

[0007] The printed circuit board includes multiple circuit layers and multiple dielectric layers stacked and bonded together in sequence; wherein the metallized half-ring conducts at least three circuit layers.

[0008] The ratio of the arc length of the metallized semi-ring to the arc length of the corresponding metallized hole ranges from 0.20% to 0.40%.

[0009] The ratio of the arc length of the metallized semi-ring to the arc length of the corresponding metallized hole is in the range of 0.25%.

[0010] In this case, each metallized half-ring corresponding to the same metallized hole is connected to a different conductive line in the printed circuit board.

[0011] To solve the above-mentioned technical problems, the present invention provides a drilling method for printed circuit boards, comprising: obtaining a board to be drilled; mechanically drilling and metallizing one side of the board to be drilled to form a metallized hole; plugging the metallized hole; and mechanically milling the hole wall of the metallized hole at least twice until the metallized hole is divided into at least two metallized semi-rings, so as to conduct the printed circuit board through at least two metallized semi-rings respectively.

[0012] The steps of mechanically drilling and metallizing one side of the board to be drilled to form a metallized hole include: mechanically drilling one side of the board to be drilled to form at least one target hole; wherein the target hole penetrates at least three circuit layers; and electroplating copper onto the hole walls of each target hole to form each metallized hole.

[0013] The step of plugging the metallized holes includes: filling the metallized holes with resin and grinding the surface of the plate to be drilled until the surface is smooth.

[0014] The step of performing at least two mechanical milling operations on the wall of the metallized hole to divide the metallized hole into at least two metallized semi-rings, so as to conduct the workpiece to be drilled through the at least two metallized semi-rings respectively, further includes: performing at least two mechanical drilling operations on the wall of each metallized hole to form at least two dividing holes, so as to divide the corresponding metallized hole into at least two metallized semi-rings through the at least two dividing holes; filling each dividing hole with resin, and grinding the surface of the workpiece to be drilled until the surface is smooth.

[0015] The steps of performing at least two mechanical milling operations on the wall of the metallized hole until the metallized hole is divided into at least two metallized semi-rings to conduct the material to be drilled through at least two metallized semi-rings respectively, further include: electroplating one side of the material to be drilled to form a conductive layer; etching the conductive layer to form conductive lines; and preparing connecting conductive components at the positions corresponding to the conductive layer and each metallized semi-ring.

[0016] The beneficial effects of this invention are as follows: Unlike the prior art, the printed circuit board of this invention divides the same metallized hole into at least two metallized half-rings and conducts the printed circuit board through the metallized half-rings respectively. This can greatly reduce the spacing between the two metallized half-rings and achieve a high network density design for the printed circuit board. It also improves the compatibility between smaller hole spacing and fewer hole pressing times. Furthermore, the number of pressing times in the preparation of the metallized half-rings in this embodiment is the same as the number of pressing times for the metallized holes, so there is no need to increase the number of pressing times. Thus, while reducing the hole spacing, the steps of the printed circuit board are simplified, and the preparation efficiency of the printed circuit board is improved. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the structure of a printed circuit board according to an embodiment of the present invention;

[0018] Figure 2 yes Figure 1 A schematic diagram of the front cross-sectional structure of the printed circuit board in the embodiment;

[0019] Figure 3 This is a schematic flowchart of an embodiment of the drilling method for printed circuit boards of the present invention;

[0020] Figure 4 This is a structural schematic diagram of one embodiment after the sheet metal is metallized. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0023] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0024] Please see Figure 1-2 , Figure 1 This is a schematic diagram of the structure of a printed circuit board according to an embodiment of the present invention. Figure 2 yes Figure 1 A schematic diagram of the front cross-sectional structure of the printed circuit board in the embodiment.

[0025] In this embodiment, at least two spaced-apart metallized half-rings 101 are formed on the printed circuit board 100. Each metallized half-ring 101 is electrically connected to the printed circuit board 100.

[0026] In this embodiment, each pair of adjacent and corresponding metallized semi-rings 101 is formed by dividing the same metallized hole. That is, the metallized semi-rings 101 in this embodiment are obtained by dividing the metallized hole. At least two metallized semi-rings 101 located on the hole wall of the same metallized hole correspond to each other.

[0027] The metallized holes in this embodiment are obtained through mechanical drilling and metallization. The depth of the holes can be controlled during the mechanical drilling step to obtain holes that penetrate multiple layers. Therefore, during lamination, the printed circuit board 100 does not need to consider the preparation of the holes and can be prepared using conventional lamination. Consequently, the preparation of the metallized semi-ring 101 in this embodiment does not need to change the conventional lamination preparation process, and the function of connecting multiple circuit layers 103 can be realized, thereby improving the preparation efficiency of the printed circuit board 100.

[0028] Specifically, the number of metallized half-rings 101 that can be divided into the same metallized hole can be 2, 3 or 4, etc., which can be set according to actual needs and is not limited here.

[0029] In a specific application scenario, adjacent and corresponding metallized semi-rings 101 can be filled with resin or other insulating materials to plug the holes, thereby setting metallized semi-rings 101 and supporting metallized semi-rings 101 at intervals to improve the structural stability and reliability of each metallized semi-ring 101.

[0030] The metallized semi-ring 101 formed by dividing the same metallized hole can arbitrarily conduct the circuits in the printed circuit board 100. That is, the metallized hole can be a metallized blind hole, a metallized buried hole, and / or a metallized through hole. The specific circuit layers it conducts can be 2 layers, 3 layers, 6 layers, or 10 layers, etc., which are set according to the actual needs of the printed circuit board 100 and are not limited here.

[0031] Since the metallized half-rings 101 in this embodiment are formed by dividing metallized vias, a smaller spacing between the metallized half-rings can be achieved simply by controlling the aperture of the metallized vias. Therefore, the metallized half-rings 101 formed by dividing metallized vias in this embodiment can connect multiple circuit layers 103 while achieving a smaller spacing, improving the compatibility between the smaller via spacing and fewer via pressing times. Specifically, the distance between adjacent and corresponding metallized half-rings 101 is half the difference between two metallized vias, resulting in a significant increase in network density.

[0032] With the above structure, the printed circuit board of this embodiment can greatly reduce the spacing between the two metallized half-rings by dividing the same metallized hole into at least two metallized half-rings and conducting the printed circuit board through the metallized half-rings respectively. This enables a high network density design of the printed circuit board, improves the compatibility between smaller hole spacing and fewer hole pressing times, and the pressing times in the preparation of the metallized half-rings in this embodiment are the same as the pressing times of the metallized holes, so there is no need to increase the pressing times. Thus, while reducing the hole spacing, the steps of the printed circuit board are simplified, and the preparation efficiency of the printed circuit board is improved.

[0033] In other embodiments, the printed circuit board 100 includes multiple circuit layers 103 and multiple dielectric layers 104 that are stacked and bonded together in sequence, wherein the metallized semi-ring 101 can penetrate at least three circuit layers 103.

[0034] Conductive lines 102 are formed on each circuit layer 103. The material of the conductive lines of the circuit layer 103 may include copper, silver, gold, alloy or other conductive materials, which are not limited here. The dielectric layer 104 may specifically include one or more of epoxy resin, polyimide, bismaleimide triazine (BT) and ceramic matrix.

[0035] The metallized half-ring 101 can conduct at least three circuit layers 103, thereby connecting the multi-layer circuit layers 103 of the printed circuit board 100 and realizing multi-layer conduction function.

[0036] In other embodiments, when the printed circuit board 100 needs to connect two circuit layers 103, the two circuit layers 103 can be connected by laser drilling or by the metallized half-ring 101 of this embodiment. No limitation is made here.

[0037] In other embodiments, the ratio of the arc length of the metallized half-ring 101 to the arc length of the corresponding metallized hole ranges from 0.20% to 0.40%, specifically 0.20%, 0.25%, 0.30%, 0.34%, 0.37%, or 0.40%, etc., and is not limited here. Within this range, the metallized half-ring 101 satisfies its conductivity requirements while maintaining a certain distance between adjacent and corresponding metallized half-rings 101 to prevent short circuits.

[0038] In other embodiments, preferably, the ratio of the arc length of the metallized half-ring 101 to the arc length of the corresponding metallized hole is in the range of 0.25%. This ratio can meet its conductivity requirements, maintain a certain distance between it and the adjacent and corresponding metallized half-rings 101 to avoid short circuits, and provide sufficient operating space for the segmentation operation, thereby improving the reliability of the segmentation operation.

[0039] In other embodiments, each metallized half-ring 101 corresponding to the same metallized hole is connected to different conductive lines 102 in the printed circuit board 100 to achieve different conduction functions.

[0040] In other embodiments, the conductive line 102 may also be connected to the pad 106, thereby enabling electrical connection with other circuits or devices through the pad 106.

[0041] Please see Figure 3 , Figure 3 This is a flowchart illustrating an embodiment of the drilling method for printed circuit boards according to the present invention.

[0042] Step S11: Obtain the plate to be drilled.

[0043] Obtain the board to be drilled, which can include any circuit board that needs to be drilled, such as: single-layer circuit board, multi-layer circuit board, and pre-drilled circuit board.

[0044] The board to be drilled includes multiple layers of circuitry and multiple layers of dielectric material that are stacked and bonded together in sequence.

[0045] Conductive lines are formed on each circuit layer. The material of the conductive lines in the circuit layer can include copper, silver, gold, alloy or other conductive materials, which are not limited here. The dielectric layer can specifically include one or more of epoxy resin, polyimide, bismaleimide triazine (BT) and ceramic matrix.

[0046] Step S12: Perform mechanical drilling and metallization on the plate to be drilled to form metallized holes.

[0047] After obtaining the board to be drilled, mechanical drilling is performed on it. Mechanical drilling refers to the process of forming holes by cutting the board with a high-speed rotating milling cutter. Mechanical drilling can create holes that penetrate multiple circuit layers on the board, thus forming metallized holes that connect multiple circuit layers after metallization.

[0048] The depth and number of holes drilled in this step can be set based on actual needs and are not limited here.

[0049] After drilling, the holes are metallized to form metallized holes that connect the conductive layers.

[0050] In this embodiment, because the depth of the hole can be controlled during the mechanical drilling process, holes that penetrate multiple layers can be obtained. Therefore, during lamination, the printed circuit board does not need to consider the preparation of the holes and can be prepared using conventional lamination. Consequently, the preparation of the metallized half-ring in this embodiment does not need to change the conventional lamination process, and the function of connecting multiple circuit layers can be achieved, thus improving the fabrication efficiency of the printed circuit board.

[0051] Step S13: Plug the metallized holes.

[0052] Plug the metallized holes. Specifically, fill the core of the metallized holes with resin or other insulating materials to support them and improve their structural rigidity. This also prevents milling debris from remaining in the core during subsequent machining, which could affect the independent conductivity of the metallized half-ring, thereby improving the reliability and stability of the metallized half-ring.

[0053] Step S14: Perform at least two mechanical milling operations on the wall of the metallized hole until the metallized hole is divided into at least two metallized half-rings, so that the printed circuit board can be connected through at least two metallized half-holes respectively.

[0054] After plugging the holes, the hole walls of the same metallized hole are machined at least twice until each metallized hole is divided into at least two metallized semi-rings. During this machine milling, a portion of the hole wall is removed, leaving the remaining hole walls forming independent and spaced-apart metallized rings. Specifically, the number of metallized semi-rings 101 that can be divided into the same metallized hole can be 2, 3, or 4, etc., and can be set based on actual needs; no limitation is made here.

[0055] Mechanical milling refers to the process of cutting sheet metal using a high-speed rotating milling cutter. Mechanical milling can mill any shape onto a sheet metal workpiece and includes milling processes such as mechanical drilling or mechanical depth control.

[0056] At least two metallized half-rings fabricated through the same metallized via can independently conduct through the printed circuit board, achieving the conduction function of at least two conductive elements. Furthermore, the metallized half-rings in this embodiment are fabricated by milling metallized vias; therefore, they can also achieve conduction across multiple circuit layers, and the number of lamination cycles is the same as for metallized vias, eliminating the need for additional lamination cycles. The spacing between the at least two metallized half-rings fabricated through the same metallized via can be reduced by controlling the via diameter, thereby enabling a high network density design for the printed circuit board.

[0057] Through the above steps, the drilling method for printed circuit boards in this embodiment first mechanically drills and metallizes one side of the board to be drilled to form a metallized hole, and then mechanically mills the hole wall of the metallized hole at least twice until the metallized hole is divided into at least two metallized half-rings, so that the printed circuit board can be connected through at least two metallized half-holes respectively. This can greatly reduce the spacing between the two metallized half-rings, realize the high network density design of the printed circuit board, and the number of pressing times in the preparation of the metallized half-rings in this embodiment is the same as the number of pressing times in the metallized hole, so there is no need to add additional pressing times. Thus, while reducing the hole spacing, the steps of printed circuit board manufacturing are simplified, and the manufacturing efficiency of printed circuit board is improved.

[0058] In other embodiments, the steps of mechanically drilling and metallizing the board to be drilled to form a metallized hole may include: mechanically drilling the board to be drilled to form at least one target hole; wherein the target hole may penetrate at least three circuit layers, thereby enabling the subsequent metallized half-ring to conduct at least three circuit layers, achieving multi-layer conduction function.

[0059] The diameter of the target hole can be set based on the spacing requirements of the subsequent metallized half-rings, such as 0.15 mm, 0.21 mm, etc., and is not limited here. The number of target holes can also be set based on the conductivity requirements of the metallized half-rings, and is not limited here. The depth of the target hole can also be set based on the conductivity requirements of the metallized half-rings, and is not limited here.

[0060] After drilling the target holes, copper plating is performed on the hole walls to form a metal layer, thus creating metallized holes on the board. At this point, the center of the metallized hole is hollowed out, with only the metal layer on the hole wall to achieve the conductive function.

[0061] Please see Figure 4 , Figure 4 This is a structural schematic diagram of one embodiment after the sheet metal is metallized.

[0062] At least one metallized hole 201 is formed on the metallized plate 200, and the metallized holes 201 are spaced apart. A metal layer 2011 is formed on the hole wall of each metallized hole 201 for conduction.

[0063] In other embodiments, the step of plugging the metallized holes includes: filling the metallized holes with resin, which, after curing, can support the metallized holes and improve their structural rigidity. Since the resin may protrude from the plate to be drilled after plugging, the surface of the plate can be ground until it is smooth. Specifically, the resin may include one or more of epoxy resins, polyimide resins, bismaleimide triazine (BT) resins, and ceramic-based resins.

[0064] In other embodiments, the step of performing at least two mechanical milling operations on the wall of the metallized hole until the metallized hole is divided into at least two metallized semi-rings, so as to conduct the workpiece to be drilled through the at least two metallized semi-rings respectively, may further include: performing at least two mechanical drilling operations on the wall of each metallized hole to form at least two dividing holes, so as to divide the corresponding metallized hole into at least two metallized semi-rings through the at least two dividing holes, that is, the position of the dividing holes overlaps with the wall of the metallized hole to remove part of the wall of the metallized hole and form at least two independent metallized semi-rings.

[0065] In a specific application scenario, the diameter of the dividing hole can be the same as the diameter of the target hole, thus eliminating the need to adjust the parameters of the mechanical milling equipment and enabling the fabrication of different types of holes, thereby improving fabrication efficiency. Furthermore, when the diameter of the dividing hole is the same as the diameter of the target hole, the arc length of the metallized semi-ring can be easily controlled by adjusting the position of the dividing hole to meet the requirements.

[0066] After the division is completed, resin is filled into each dividing hole to support the dividing hole and improve the rigidity of the printed circuit board. In addition, considering that the resin protrudes from the board to be drilled, the surface of the board to be drilled is ground until the surface is flat to improve the flatness of the board.

[0067] In other embodiments, the ratio of the arc length of the metallized half-ring 101 to the arc length of the corresponding metallized hole ranges from 0.20% to 0.40%, specifically 0.20%, 0.25%, 0.30%, 0.34%, 0.37%, or 0.40%, etc., and is not limited here. Within this range, the metallized half-ring 101 satisfies its conductivity requirements while maintaining a certain distance between adjacent and corresponding metallized half-rings 101 to prevent short circuits.

[0068] In other embodiments, preferably, the ratio of the arc length of the metallized half-ring 101 to the arc length of the corresponding metallized hole is in the range of 0.25%. This ratio can meet its conductivity requirements, maintain a certain distance between it and the adjacent and corresponding metallized half-rings 101 to avoid short circuits, and provide sufficient operating space for the segmentation operation, thereby improving the reliability of the segmentation operation.

[0069] In other embodiments, the steps of performing at least two mechanical milling operations on the wall of the metallized hole until the metallized hole is divided into at least two metallized semi-rings to conduct the workpiece to be drilled through at least two metallized semi-rings respectively further include: electroplating one side of the workpiece to be drilled to form a conductive layer; and then etching the conductive layer to form conductive lines and pads, thereby realizing the circuit function of the conductive layer.

[0070] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A printed circuit board, characterized in that, At least two spaced metallized half-rings are formed on the printed circuit board, and each metallized half-ring is connected to the printed circuit board. Each adjacent and corresponding at least two metallized half-rings are formed by dividing the same metallized hole; The ratio of the arc length of the metallized semi-ring to the arc length of the corresponding metallized hole is in the range of 0.20-0.40%.

2. The printed circuit board according to claim 1, characterized in that, The printed circuit board includes multiple circuit layers and multiple dielectric layers that are stacked and bonded together in sequence. The metallized half-ring is connected to at least three circuit layers.

3. The printed circuit board according to claim 1, characterized in that, The ratio of the arc length of the metallized semi-ring to the arc length of the corresponding metallized hole is in the range of 0.25%.

4. The printed circuit board according to claim 1, characterized in that, Each of the metallized half-rings corresponding to the same metallized hole is connected to a different conductive line in the printed circuit board.

5. A drilling method for a printed circuit board, characterized in that, The drilling method for the printed circuit board includes: Obtain the plate to be drilled; The plate to be drilled is mechanically drilled and metallized to form metallized holes; The metallized holes are plugged; The wall of the metallized hole is machined at least twice until the metallized hole is divided into at least two metallized semi-rings, so that the printed circuit board can be connected through at least two metallized semi-rings respectively; the ratio of the arc length of the metallized semi-ring to the arc length of the corresponding metallized hole is in the range of 0.20-0.40%.

6. The drilling method for a printed circuit board according to claim 5, characterized in that, The steps of mechanically drilling and metallizing the plate to be drilled to form metallized holes include: Mechanical drilling is performed on the board to be drilled to form at least one target hole; wherein the target hole penetrates at least three circuit layers; The walls of each target hole are subjected to copper plating to form each metallized hole.

7. The drilling method for a printed circuit board according to claim 5, characterized in that, The step of plugging the metallized hole includes: The metallized holes are filled with resin, and the surface of the plate to be drilled is ground until the surface is smooth.

8. The drilling method for a printed circuit board according to claim 5, characterized in that, The step of performing at least two mechanical milling operations on the wall of the metallized hole until the metallized hole is divided into at least two metallized semi-circles, so as to conduct the hole to be drilled through at least two of the metallized semi-circles respectively, further includes: The walls of each of the metallized holes are mechanically drilled at least twice to form at least two dividing holes, so as to divide the corresponding metallized holes into at least two metallized semi-rings through the at least two dividing holes; Fill each of the divided holes with resin and grind the surface of the plate to be drilled until the surface is smooth.

9. The drilling method for a printed circuit board according to claim 5, characterized in that, The step of performing at least two mechanical milling operations on the wall of the metallized hole until the metallized hole is divided into at least two metallized semi-circles, so as to conduct the workpiece to be drilled through at least two of the metallized semi-circles respectively, further includes: Electroplating is performed on one side of the plate to be drilled to form a conductive layer; The conductive layer is etched to form conductive lines and pads.

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