CN109757041B - Process implementation method for selective vertical routing of hole wall - Google Patents

Abstract

The present invention provides a method for realizing selective vertical wiring on a hole wall, comprising: opening a slot hole on a circuit board substrate on which vertical wiring is to be arranged; filling the slot hole with anti-plating material; According to the size of the hole, a hole is opened on the circuit board substrate, and the hole intersects the edge of the slot hole; the circuit board substrate with the slot hole and the hole is electroplated, and the side wall of the hole is plated. A vertical trace with an arc-shaped cross-section is formed. Through the method provided by the present invention, while realizing high-density wiring of the circuit board substrate, the influence of the signal via hole can also be reduced.

Description

Process realization method for selective vertical routing of hole wall

technical field

The invention relates to the technical field of circuit board fabrication, in particular to a process realization method for selective vertical wiring of hole walls.

Background technique

With the development of high-density printed circuit boards, the number of circuit boards is getting higher and higher, the line width is getting thinner, and the lines are getting denser, especially for the solder ball array package (English: Ball Grid Array, referred to as: BGA) area, it is difficult to meet the high-density wiring requirements of next-generation printed circuit boards according to the current process implementation method.

In the BGA area or dense circuit area of the current printed circuit board, different signal layers are connected through hole metallization. A hole is electroplated to form a tubular vertical trace, and the line width of the vertical trace is determined by the size of the aperture (line width). about 3.14 times the aperture).

However, with the rapid development of electronic products, the requirements for printed circuit boards to be light, thin and short are getting higher and higher, and the design of dense circuits requires smaller apertures, which challenges the technical difficulty of existing drilling. On the other hand, the effect of electroplating in small holes is also greatly reduced, and it is easy to generate open circuits. Therefore, due to the limit ability of drilling and electroplating, high-density wiring design cannot be carried out based on the existing technology.

SUMMARY OF THE INVENTION

The invention provides a process realization method for selective vertical wiring of hole walls, which is used to reduce the influence of signal via holes while realizing high-density wiring of circuit board substrates.

A first aspect of the present invention is to provide a process implementation method for selective vertical wiring on a hole wall, including: opening a slot hole on a circuit board substrate where vertical wiring is to be arranged; filling the slot hole with a plating resist material; According to the preset hole position and hole size, a hole is opened on the circuit board substrate, and the hole intersects with the edge of the slot hole; electroplating is performed on the circuit board substrate with the slot hole and the hole opened, and the The sidewall of the hole forms a vertical line with an arc-shaped cross section.

Further, performing electroplating treatment on the circuit board substrate on which the slot hole and the hole have been opened, after forming a vertical line with an arc-shaped cross section on the side wall of the hole, further comprising: according to a preset circuit , fabricating an outer layer circuit on the circuit board substrate on which the vertical wiring has been formed, and the outer layer circuit is connected with the vertical wiring.

Further, according to the preset circuit, before fabricating the outer layer circuit on the circuit board substrate on which the arc-shaped vertical traces have been formed, the method further includes: applying the anti-plating method in the slot hole of the circuit board substrate after electroplating is completed. The material is returned for washing.

Further, according to the preset circuit, after the outer layer circuit is fabricated on the circuit board substrate on which the arc-shaped vertical wiring has been formed, the method further includes: filling the slot holes with solder resist oil, and applying the outer layer circuit on the outer layer circuit. Print solder mask oil.

Further, the filling of the slot hole with the anti-plating material includes: injecting the anti-plating material before curing into the slot hole; and curing the anti-plating material in the slot hole.

Further, the anti-plating material includes: one or more of ink, resin, paraffin, and paint with anti-plating properties.

Further, after filling the slot hole with a plating resist material, the method further includes: removing the excess plating resist material around the slot hole.

Further, the opening of holes on the circuit board substrate according to the preset hole positions and hole sizes includes: obtaining preset parameters of the hole positions and hole sizes in the circuit; according to the parameters, according to the preset holes The position and the size of the holes provide holes on the circuit board substrate.

Further, the opening of the slot holes on the circuit board substrate where the vertical wiring is to be arranged includes: opening the slot holes on the circuit board substrate where the vertical wiring is to be arranged according to a preset ratio by the stack-hole drilling method, The length-width ratio of the slot hole is greater than 1:1.2.

The circuit board substrate includes a laminate substrate having multiple insulating boards and at least one inner wiring layer.

The present invention provides a method for realizing the selective vertical wiring of the hole wall. By opening a slot hole on the circuit board substrate where the vertical wiring is to be arranged, and filling the slot hole with anti-plating material, according to the preset hole positions and holes A plurality of holes are opened on the edge of the slot hole, and the circuit board substrate with the slot hole and the hole is electroplated, and a vertical line with an arc-shaped cross-section is formed on the side wall of the hole. Therefore, while realizing high-density wiring on the circuit board substrate, the influence on the signal via holes can also be reduced.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

FIG. 1 is a flowchart of a process implementation method for selective vertical routing of hole walls according to Embodiment 1 of the present invention;

FIG. 2 is a flowchart of a process implementation method for selective vertical routing of hole walls provided in Embodiment 2 of the present application;

FIG. 3 is a schematic structural diagram of a circuit board substrate provided with a slot hole provided in Embodiment 2 of the present invention;

4 is a schematic structural diagram of a circuit board substrate after being filled with over-plating resist ink according to Embodiment 2 of the present invention;

FIG. 5 is a schematic structural diagram of the circuit board substrate after opening the holes according to the second embodiment of the present invention;

6 is a schematic structural diagram of a circuit board substrate after electroplating provided in Embodiment 2 of the present invention;

7 is a schematic structural diagram of a circuit board substrate after backwashing provided in Embodiment 2 of the present invention;

FIG. 8 is a structural example diagram of a circuit board substrate after horizontal wirings are provided according to Embodiment 2 of the present invention.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

For the convenience of description, the sizes of different layers and regions are enlarged or reduced, so the sizes and ratios shown in the figures do not necessarily represent actual sizes, nor do they reflect the proportional relationship of sizes.

With the development of high-density printed circuit boards, the number of circuit boards is getting higher and higher, the line width is getting thinner, and the lines are getting denser, especially for the solder ball array package (English: Ball Grid Array, referred to as: BGA) area, it is difficult to meet the high-density wiring requirements of next-generation printed circuit boards according to the current process implementation method.

In the BGA area or dense circuit area of the current printed circuit board, different signal layers are connected through hole metallization. A hole is electroplated to form a tubular vertical trace, and the line width of the vertical trace is determined by the size of the aperture (line width). about 3.14 times the aperture).

However, with the rapid development of electronic products, the requirements for printed circuit boards to be light, thin and short are getting higher and higher, and the design of dense circuits requires smaller apertures, which challenges the technical difficulty of existing drilling. On the other hand, the effect of electroplating in small holes is also greatly reduced, and it is easy to generate open circuits. Therefore, due to the limit ability of drilling and electroplating, high-density wiring design cannot be carried out based on the existing technology.

The technical solutions of the present invention and how the technical solutions of the present application solve the above-mentioned technical problems will be described in detail below with specific examples. The following specific embodiments may be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. Embodiments of the present invention will be described below with reference to the accompanying drawings.

Hereinafter, some terms in the present application will be explained so as to facilitate the understanding of those skilled in the art.

Printed circuit board: also known as printed circuit board, referred to as circuit board, English full name Printed Circuit Board, English abbreviation PCB, is the support of circuit components and devices in electronic products.

Wiring: It is a metal wire arranged on a printed circuit board, which is used to provide electrical connection between circuit elements and devices on the printed circuit board.

Vertical wiring: The printed circuit board can be divided into single-sided, double-sided and multi-layer boards according to the number of layers of the circuit layer (also known as the wiring layer). Layer connection traces.

Planar wiring: refers to the wiring arranged in the circuit layer of the printed circuit board.

Circuit board substrate: refers to the raw materials or semi-finished products before vertical wiring is laid in the process of printing circuit boards.

Anti-plating material: refers to a material with anti-plating properties. After electroplating, the surface of the anti-plating material will not adhere to the surface of the electroplating layer, such as anti-plating ink.

Electroplating: refers to the process of plating a thin layer of metal on the surface of a material using the principle of electrolysis, and the thin layer of metal can become an electroplating layer.

FIG. 1 is a flowchart of a process implementation method for selective vertical routing of hole walls provided in Embodiment 1 of the present invention. As shown in FIG. 1 , the method includes:

101. Open a slot hole on the circuit board substrate on which the vertical wiring is to be arranged.

In this embodiment, firstly, slot holes should be formed on the circuit board substrate after pressing. Specifically, a stack hole drilling method can be used to open a slot on the circuit board substrate to be provided with vertical wiring according to a preset ratio. The size of the slot hole can be changed according to user needs. Specifically, the length-width ratio of the slot hole needs to be greater than 1:1.2. For example, the length-width ratio of the slot hole can be 1:1.5, and the slot hole is Do not penetrate the cavity of the circuit board substrate. Specifically, the stacked hole drilling method is to use a drilling machine to open a plurality of slot holes with smaller diameters on the circuit board substrate, and form the slot holes in a multi-hole integrated manner according to a preset ratio.

It should be noted that the circuit board substrate includes a laminate substrate having multiple insulating boards and at least one inner wiring layer. Specifically, the circuit board substrate provided in the embodiment of the present invention may be a double-layer board composed of a single-layer insulating board and wiring layers on both sides of the insulating board, or may be at least a multi-layer insulating board and at least one layer of inner wiring. layer and at least one outer wiring layer, the multilayer laminate substrate may also be provided with a semiconductor layer or a metal layer.

102. Fill the slot hole with a plating resist material.

In this embodiment, after the slot hole is formed, the slot hole needs to be filled with a plating resist material. Specifically, the anti-plating material can be selected from one of ink, resin, paraffin, and paint with anti-plating properties, or one of the above It is a composite material with anti-plating properties composed of some materials in a variety of materials, such as anti-plating UV (English full name: Ultraviolet, Chinese name: ultraviolet) ink, anti-plating insulating paint, etc.

103. Opening holes on the circuit board substrate according to preset hole positions and hole sizes, where the holes intersect or are separated from the edge of the slot holes.

In this embodiment, after filling the slot holes with anti-plating material, holes are opened on the circuit board substrate according to the preset hole positions and hole sizes, wherein the number of holes is determined according to user requirements, the holes and the slot holes The edges intersect or separate, wherein, in order to meet the user's functional requirements for the finished circuit board, the positional relationship between the slot and the hole can be determined by a preset circuit diagram. Specifically, the specific opening method of the hole may be using a drill to open the hole by cutting, or using a laser to open the hole by burning, or using a punching machine to punch the hole. The hole may be a through hole penetrating the circuit board substrate, or a concave hole not penetrating the circuit board substrate.

It should be noted that, in the process of opening the holes, the position and size of the holes can be set in advance, so the purpose of high-density wiring can be achieved by shortening the distance between the holes. Specifically, since the distance between the holes can be adjusted, the requirements for the hole diameter are not high. Compared with the prior art, there is no need to make holes with smaller diameters, and the line width can be produced only by reducing the distance between the holes. Thinner, higher-density vertical traces, and narrowing the spacing between holes are less technically difficult and easier to achieve than narrowing the aperture, and can also reduce manufacturing costs.

104. Perform electroplating on the circuit board substrate on which the slot holes and the holes have been opened, and form vertical traces with arc-shaped cross-sections on the sidewalls of the holes.

In this embodiment, after the slot holes and a plurality of holes are opened on the circuit board substrate, the circuit board substrate can be put into the electrolyte for electroplating. After the electroplating is completed, the previously opened slot holes have been filled with The anti-plating material forms the anti-plating layer, and the other parts of the circuit board substrate are not filled with the anti-plating material, that is, the plated area. Therefore, after the whole board electroplating, no electroplating layer will be formed in the anti-plating area, but the electroplating layer can be formed in the plated area. Therefore, a vertical trace with an arc-shaped cross-section can be formed on the side wall of the hole, so that wiring can be carried out in the hole. . In addition, since the slot holes are filled with plating resist material in advance, it is easier to control the fabrication accuracy of vertical traces, and it will not be affected by the poor electroplating effect if the hole diameter is too small. Precision vertical traces meet the needs of high-precision wiring. Through the above method, arc-shaped vertical traces can be formed on the circuit board substrate, so that the influence of the signal on the via hole can be reduced, so that the signal transmission quality can be improved on the basis of realizing high-density wiring.

According to the process implementation method for selective vertical wiring on the hole wall provided in this embodiment, slot holes are opened on the circuit board substrate where the vertical wiring is to be arranged, and the slot holes are filled with anti-plating materials, according to the preset position of the holes. According to the size of the hole, a plurality of holes are opened on the edge of the slot hole, and the circuit board substrate with the slot hole and the hole is electroplated, and a vertical line with an arc-shaped cross-section is formed on the side wall of the hole. Therefore, while realizing high-density wiring on the circuit board substrate, the influence on the signal via holes can also be reduced.

Further, considering that it is difficult to directly fill the solid material into the slot hole and it is difficult to adhere to the slot hole, therefore, on the basis of the first embodiment of the present invention, the anti-plating material can be selected from a curable material, Filling the slot hole with a plating resist material includes:

injecting the anti-plating material before curing into the slot hole;

The plating resist material in the slot hole is cured.

Wherein, according to the curing properties of the selected anti-plating material, a corresponding curing process can be flexibly selected to cure the anti-plating material in the slot hole. For example, for anti-plating UV ink, a curing process of ultraviolet irradiation can be used for curing. ; For the anti-plating insulating paint, the curing process of drying can be used for curing, etc., which will not be repeated here.

Considering that, in the actual processing process, after the anti-plating material is filled into the slot hole, the anti-plating material may be more out of the slot hole, so as to remain on the surface of the circuit board substrate, affecting the In the subsequent process, for example, when the anti-plating insulating varnish is injected into the slot hole, due to the influence of the surface tension of the liquid, a part of the anti-plating insulating varnish will inevitably flow out of the slot hole. Therefore, on the basis of any of the foregoing embodiments, after filling the plurality of slot holes with a plating resist material, the method further includes: removing the plating resist material overflowing from the slot holes. Specifically, after the plating resist material is cured, scraping or grinding may be used to remove the plating resist material overflowing the slot hole.

Further, on the basis of any of the above-mentioned embodiments, the circuit board substrate with the slot holes and the holes already opened is electroplated, and a vertical line with an arc-shaped cross-section is formed on the sidewall of the hole. After that, also include:

According to a preset circuit, an outer layer circuit is fabricated on the circuit board substrate on which the vertical wiring has been formed, and the outer layer circuit is connected with the vertical wiring.

In this embodiment, after electroplating the circuit board substrate on which the slot holes and the holes have been opened, so that vertical traces with an arc-shaped cross section are formed on the circuit board substrate, the The outer layer plane traces are made on the circuit board substrate, so that the outer layer plane traces are connected with the vertical traces. Thus, a via is formed between the planar trace and the vertical trace.

Further, on the basis of the above embodiment, before fabricating the outer layer circuit on the circuit board substrate on which the arc-shaped vertical wiring has been formed according to the preset circuit, the method further includes:

The anti-plating material in the slot hole of the circuit board substrate after electroplating is removed and washed.

In this embodiment, it is considered that after step 104, there are still anti-plating materials in the slot holes, and these anti-plating materials may have additional adverse effects on the subsequent manufacturing process of the printed circuit board. Therefore, the anti-plating materials can be removed. the plating resist material remaining on the circuit board substrate. In specific implementation, the anti-plating material can be removed by chemical corrosion with organic solution, ultrasonic cleaning, etc. For example, the anti-plating material in the slot hole can be removed by using an alkaline solution or a horizontal line device with an alkaline solution. wash.

Further, on the basis of the above-mentioned embodiment, the opening of holes on the circuit board substrate according to the preset hole positions and hole sizes includes:

Obtain the parameters of the hole position and hole size in the preset circuit;

According to the parameters, holes are opened on the circuit board substrate according to preset hole positions and hole sizes.

In this embodiment, in order to make the finished circuit board meet the user's functional requirements, the position and size of the hole can be determined according to the pre-drawn circuit diagram, so that according to the preset parameters of the hole position and hole size in the circuit, Drilling holes on the circuit board substrate, because the distance between the holes can be adjusted, so the requirements for the aperture are not high. The spacing can produce vertical traces with thinner line width and higher density, and reducing the spacing between holes is less technically difficult and easier to achieve than reducing the aperture, and can also reduce manufacturing costs.

Further, on the basis of the above-mentioned embodiment, after the outer layer circuit is fabricated on the circuit board substrate on which the arc-shaped vertical wiring has been formed according to the preset circuit, the method further includes:

Solder mask oil is filled in the slot holes, and solder mask oil is printed on the outer circuit.

In this embodiment, after the outer layer circuit is fabricated on the circuit board substrate on which the arc-shaped vertical traces have been formed, according to the specific needs of the user, it is possible to choose whether to fill the slot hole with solder mask oil, and print the protection layer on the outer layer circuit. Soldering oil is sent to the post-processing section to finally obtain the finished printed circuit board. Among them, the solder resist oil may be a resin material.

With the method for realizing the selective vertical wiring of the hole wall provided by the present invention, it is not necessary to use an unconventional process to reduce the aperture of the vertical wiring. Therefore, the process cost can be reduced while realizing high-density wiring.

FIG. 2 is a flowchart of a process implementation method for selective vertical routing of hole walls according to Embodiment 2 of the present invention, FIG. 3 is a schematic structural diagram of a circuit board substrate provided with slot holes provided in Embodiment 2 of the present invention, and FIG. 4 is The second embodiment of the present invention provides a schematic structural diagram of the circuit board substrate after filling with anti-plating ink. FIG. 5 is a schematic structural diagram of the circuit board substrate after opening the holes according to the second embodiment of the present invention. FIG. 6 is the second embodiment of the present invention. Provided is a schematic structural diagram of a circuit board substrate after electroplating. FIG. 7 is a schematic structural diagram of a circuit board substrate after backwashing provided by Embodiment 2 of the present invention. FIG. 8 is a circuit provided by Embodiment 2 of the present invention after setting horizontal wiring. For example diagrams of the structure of the board substrate, please refer to FIG. 2 to FIG. 8 . Embodiment 2 provides a more specific embodiment, and the method specifically includes the following steps:

201. According to the normal process of the PCB, the inner layer pattern of the laminate is made, the laminate is pressed, and the semi-finished product obtained after pressing is used as the circuit board substrate.

202 . According to the size and position parameters of the slot holes in the pre-designed processing drawings, the slot holes are formed on the circuit board substrate by the stacking drilling method. Specifically, the slot holes are concave holes that do not penetrate the circuit board substrate.

203. Use a plug machine to fill the anti-plating ink in the opened slot holes, use film exposure to develop and remove the unwanted anti-plating ink around the slot holes after pre-baking, and use a UV machine to cure it.

204. According to the size and position parameters of the holes in the pre-designed processing drawings, holes are formed on the circuit board substrate with the slotted holes, wherein the holes can be holes that penetrate the circuit board substrate or do not penetrate the circuit board substrate. The specific form is determined by the pre-designed machining drawings.

205. Perform whole-board electroplating on the circuit board substrate after the secondary drilling has been completed, so as to form a vertical line with an arc-shaped cross-section at the hole.

206. Soak the electroplated circuit board substrate with an alkaline solution or a horizontal line device with an alkaline solution, so that the anti-electroplating ink in the slot hole is washed and dried.

207. Set up horizontal traces on the circuit board substrate according to the preset processing drawings, wherein the horizontal traces are connected with the vertical traces to form an inner layer circuit in which the outer layer is connected with the arc-shaped vertical traces in the slot holes.

208. Fill the slot hole with solder mask oil and print the solder mask oil on the outer circuit to protect the arc vertical wiring in the slot hole and the outer horizontal wiring.

According to the process implementation method for selective vertical wiring on the hole wall provided in this embodiment, slot holes are opened on the circuit board substrate where the vertical wiring is to be arranged, and the slot holes are filled with anti-plating materials, according to the preset position of the holes. According to the size of the hole, a plurality of holes are opened on the edge of the slot hole, and the circuit board substrate with the slot hole and the hole is electroplated, and a vertical line with an arc-shaped cross-section is formed on the side wall of the hole. Therefore, while realizing high-density wiring on the circuit board substrate, the influence on the signal via holes can also be reduced.

The present invention also provides a printed circuit board, the printed circuit board is processed based on the production methods for vertical wiring provided in Embodiments 1 and 2. For related content, please refer to the above-mentioned Embodiments 1 and 2. Two explanations to understand. The above-mentioned printed circuit boards can meet the current high-performance multi-channel servers and high-end applications such as aerospace and other high-end applications for printed circuit boards that are light, thin, short, and high-density traces. Effectiveness of signal transmission.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, for the specific working process of the device described above, reference may be made to the corresponding process in the foregoing method embodiments, which will not be repeated here.

Those of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments may be completed by program instructions related to hardware. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the steps including the above method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. scope.

Claims (8)

1. a process realization method of selective vertical alignment of hole wall, is characterized in that, comprises: Slotted holes are formed on the circuit board substrate where the vertical wiring is to be arranged; Filling the slot hole with a plating resist material; A plurality of holes are opened on the circuit board substrate according to preset hole positions and hole sizes, and the holes intersect with the edge of the slot hole; Electroplating is performed on the circuit board substrate on which the slot hole and the hole have been opened, and a vertical line with an arc-shaped cross-section is formed on the side wall of the hole; Filling the slot hole with a plating resist material includes: injecting the anti-plating material before curing into the slot hole; curing the anti-plating material in the slot hole; The slotted holes are formed on the circuit board substrate on which the vertical wiring is to be arranged, including: Slot holes are formed on the circuit board substrate on which vertical wirings are to be arranged according to a preset ratio by the stacking hole drilling method, and the length-width ratio of the slot holes is greater than 1:1.2. 2 . The method according to claim 1 , wherein the electroplating process is performed on the circuit board substrate on which the slot hole and the hole have been opened, and a vertical arc-shaped cross-section is formed on the side wall of the hole. 3 . After routing, also include: According to a preset circuit, an outer layer circuit is fabricated on the circuit board substrate on which the vertical wiring has been formed, and the outer layer circuit is connected with the vertical wiring. 3. The method according to claim 2, wherein, according to the preset circuit, before fabricating the outer layer circuit on the circuit board substrate on which the arc-shaped vertical wiring has been formed, the method further comprises: The anti-plating material in the slot hole of the circuit board substrate after electroplating is removed and washed. 4 . The method according to claim 2 , wherein, according to the preset circuit, after the outer layer circuit is fabricated on the circuit board substrate on which the arc-shaped vertical wiring has been formed, the method further comprises: 5 . Solder mask oil is filled in the slot holes, and solder mask oil is printed on the outer circuit. 5 . The method according to claim 1 , wherein the anti-plating material comprises: one or more of ink, resin, paraffin, and paint with anti-plating properties. 6 . 6 . The method according to claim 1 , wherein after filling the slot hole with a plating resist material, the method further comprises: 6 . The excess of the plating resist material around the slot hole is removed. 7. The method according to claim 1, wherein the opening of holes on the circuit board substrate according to preset hole positions and hole sizes comprises: Obtain the parameters of the hole position and hole size in the preset circuit; According to the parameters, a plurality of holes are opened on the circuit board substrate according to preset hole positions and hole sizes. 8. The method according to any one of claims 1-7, wherein the circuit board substrate comprises a laminate substrate having a multilayer insulating board and at least one inner wiring layer.

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