Processing method of multi-stage blind hole printed circuit board and circuit board

Abstract

The invention provides a processing method of a multi-stage blind hole printed circuit board and a circuit board, and belongs to the technical field of circuit board production, and the method comprises the steps: obtaining a printed circuit board; determining the parameter condition of the printed circuit board, and determining the diameter, depth and order of a to-be-processed blind hole in the printed circuit board; determining laser processing parameters according to the parameter condition of the printed circuit board and the diameter, depth and order of the to-be-processed blind hole; according to the determined laser processing parameters, multi-order blind holes are processed in the printed circuit board at a time without pretreatment through target laser; carrying out hole filling electroplating and subsequent process treatment on the processed blind hole; wherein the width of the target laser pulse is less than 10 picoseconds and belongs to an ultraviolet band. The method can effectively reduce the processing difficulty of the multi-stage blind hole of the circuit board, is beneficial to improving the production efficiency of the circuit board, and guarantees the production quality of the circuit board.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit board production, and particularly relates to a processing method of a multi-stage blind hole printed circuit board and a circuit board. BACKGROUND

[0002] With the development of electronic devices towards smaller and higher performance, the performance requirements of printed circuit boards are also increasingly high. Especially in the field of high-end communication products, the demand for high frequency and high speed and large capacity data transmission promotes the design of printed circuit boards to a higher level of high density interconnection (HD I). Under this trend, multi-stage blind hole technology becomes particularly important because it can significantly improve the line density and production efficiency. Multi-stage blind hole refers to drilling from a certain layer of the PCB to the specified layer without penetrating the whole board, and then conducting through metalization by one-time electroplating to achieve efficient interconnection between layers. Since the multi-stage blind hole needs to cross multiple layers, its thickness-to-diameter ratio is high, and the processing difficulty is great, and the processing quality directly affects the final quality of the HD I board.

[0003] At present, the processing of blind holes on PCBs mainly adopts CO2 laser technology. However, CO2 laser belongs to far-infrared laser, and its absorption rate on copper foil is extremely low, so a pretreatment step such as copper reduction brown oxidation or etching window opening is needed before processing to improve the absorption rate of laser energy on copper foil. This pre-treatment method not only increases the complexity of the process, but also introduces additional costs and time. For the processing of multi-stage blind holes, the traditional method needs to complete laser, electroplating and pattern making layer by layer, and then press together, and the multi-stage blind hole is made by repeating these processes. This method not only has complicated process and long time-consuming, but also has high requirements for interlayer alignment, which increases the processing difficulty and cost. In addition, due to the significant difference in absorption rate and thermodynamic properties of copper foil, resin and glass fiber, CO2 laser as a long pulse laser can easily cause quality problems such as hole wall copper suspension, glass fiber protrusion, heat affected zone and recast layer during processing, which further affects the processing effect and product quality.

[0004] Therefore, it is an urgent need in the industry to explore a more efficient and high-quality processing method for multi-stage blind holes of printed circuit boards. SUMMARY

[0005] To overcome the problems in the related art, one of the purposes of the present application is to provide a processing method of a multi-stage blind hole printed circuit board, which can effectively reduce the processing difficulty of the multi-stage blind hole of the circuit board, help to improve the production efficiency of the circuit board, and ensure the production quality of the circuit board.

[0006] A processing method of a multi-stage blind hole printed circuit board, comprising:

[0007] obtaining a printed circuit board;

[0008] Determine the parameter condition of the printed circuit board, and determine the diameter, depth and order of the blind hole to be processed on the printed circuit board;

[0009] Determine the laser processing parameters according to the parameter condition of the printed circuit board, the diameter, depth and order of the blind hole to be processed;

[0010] According to the determined laser processing parameters, the target laser is used to process the blind hole on the printed circuit board at one time;

[0011] The processed blind hole is filled with electroplating and subsequent process treatment;

[0012] Among them, the target laser pulse width is less than 10 picoseconds and belongs to the ultraviolet band.

[0013] In the preferred technical solution of the present application, after the blind hole is processed on the printed circuit board at one time, and before the processed blind hole is filled with electroplating, it further comprises:

[0014] Obtain the processing effect of the processed blind hole;

[0015] According to the processing effect of the blind hole, it is judged whether the processed blind hole needs to be processed at one time.

[0016] In the preferred technical solution of the present application, the processing effect of the blind hole comprises:

[0017] Whether there is resin remaining in the blind hole;

[0018] Whether the bottom copper of the blind hole is damaged;

[0019] Whether the diameter, depth, roundness and taper of the blind hole exceed the set threshold.

[0020] In the preferred technical solution of the present application, according to the processing effect of the blind hole, it is judged whether the processed blind hole needs to be processed at one time, comprising:

[0021] If there is resin remaining in the blind hole, the processed blind hole is processed at one time;

[0022] Among them, when the second processing, the laser processing parameters need to be adjusted to avoid low copper damage.

[0023] In the preferred technical solution of the present application, if the bottom copper of the blind hole is damaged when processed at one time, the laser processing parameters when processed at one time are adjusted;

[0024] Among them, adjusting the laser processing parameters when processed at one time includes reducing the laser frequency and reducing the processing times.

[0025] In the preferred technical solution of the present application, if the taper of the blind hole exceeds the set threshold when processed at one time, the focus of the laser processing parameters is reduced for processing.

[0026] In the preferred technical solution of the present application, the parameter conditions of the printed circuit board include the number of layers, structure and thickness of the printed circuit board.

[0027] The structure includes copper in the inner layer and no copper in the inner layer of the printed circuit board.

[0028] The thickness includes the thickness of the copper foil of each layer and the thickness of the substrate layer of the printed circuit board.

[0029] In the preferred technical solution of the present application, the laser processing parameters include laser type, laser power, repetition frequency, processing times, scanning speed, filling path and spacing.

[0030] The filling path includes concentric circle filling, spiral line filling or serpentine filling.

[0031] In the process of processing the blind hole, the filling path and the spacing are changed according to the blind hole processing effect.

[0032] The second object of the present application is to provide a printed circuit board produced by the above-mentioned processing method of a multi-step blind hole printed circuit board.

[0033] The circuit board includes a plurality of core boards, and in the manufacturing process, the core boards with completed circuit patterns are pre-stacked according to design requirements, and then the printed circuit board is obtained by overall pressing.

[0034] The beneficial effects of the present application are:

[0035] The present application provides a processing method of a multi-step blind hole printed circuit board, which comprises: obtaining a printed circuit board; determining the parameter conditions of the printed circuit board, and determining the diameter, depth and number of steps of the blind hole to be processed on the printed circuit board; determining the laser processing parameters according to the parameter conditions of the printed circuit board, the diameter, depth and number of steps of the blind hole to be processed; processing the blind hole on the printed circuit board once without pretreatment by using target laser according to the determined laser processing parameters; filling the hole and electroplating the processed blind hole and subsequent process; wherein the target laser pulse width is less than 10 picoseconds and belongs to the ultraviolet band. The method obtains the parameter conditions of the whole circuit board, processes the blind hole on the circuit board once by using laser, and uses ultrafast laser with pulse width less than 10 picoseconds, which reduces the thermal influence on the surrounding material, so that high-quality multi-step blind holes can be processed directly without pretreatment, which can ensure the accurate processing of the blind hole and improve the processing quality and efficiency. The method can complete the processing of multi-step blind holes at one time, avoiding multiple processing and complex process flow, thereby greatly improving the production efficiency of the circuit board. This not only shortens the production cycle, but also reduces the production cost. Due to the simplification of the processing process, the possibility of human error and process fluctuation is also reduced, further ensuring the production quality of the circuit board.

[0036] The application also provides a circuit board manufactured by the processing method of the multi-step blind hole printed circuit board, which optimizes the production steps, does not need interlayer alignment in the blind hole manufacturing process, reduces the manufacturing difficulty of the circuit board, reduces the process steps of the circuit board manufacturing, shortens the production cycle, guarantees the quality of the circuit board, and reduces the manufacturing cost. BRIEF DESCRIPTION OF DRAWINGS

[0037] Reference signs:

[0038] 1. Blind hole.

[0039] Figure 1 is a flow chart of the processing method of the multi-step blind hole printed circuit board provided by the application;

[0040] Figure 2 is a flow chart of the processing method of the multi-step blind hole printed circuit board provided by the application;

[0041] Figure 3 is a flow chart of the processing method of the multi-step blind hole printed circuit board provided by the application;

[0042] Figure 4 is a schematic diagram of the laser processing of the multi-step blind hole provided by the embodiment of the application. DETAILED DESCRIPTION

[0043] The preferred embodiments of the application will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the application are shown in the drawings, it should be understood that the application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the application more thorough and complete, and to fully convey the scope of the application to those skilled in the art.

[0044] At present, the blind hole processing on the PCB mainly adopts CO2 laser technology. However, CO2 laser belongs to far-infrared laser, and the absorption rate of copper foil is very low, so a pretreatment step such as copper reduction brown oxidation or etching window opening is needed before processing to improve the absorption rate of copper foil to laser energy. This pre-treatment method not only increases the complexity of the process, but also introduces additional cost and time. For the processing of multi-stage blind holes, the traditional method needs to complete laser, electroplating, pattern making and pressing one by one, and the multi-stage blind hole is realized by repeating these processes. This method not only has complicated process and long time, but also has high requirement for interlayer alignment, which increases the processing difficulty and cost. In addition, due to the significant difference in absorption rate and thermodynamic properties of copper foil, resin and glass fiber, CO2 laser as long pulse laser can easily cause quality problems such as suspended copper, glass fiber protrusion, heat affected zone and recast layer during processing, which further affects the processing effect and product quality.

[0045] Based on this, the application provides a processing method of multi-stage blind hole printed circuit board.

[0046] Embodiment 1

[0047] As shown in Figure 1 The processing method of multi-stage blind hole printed circuit board provided by the embodiment includes:

[0048] S100, obtaining a printed circuit board;

[0049] Specifically, the printed circuit board of the application can be a multi-layer printed circuit board such as HD I, and the process of obtaining the printed circuit board is as follows:

[0050] First, make the inner layer core board, including laminating copper foil on the insulating substrate, and also including making line pattern on the inner layer core board; laminate the inner layer core board with the outer layer copper foil to form a multi-layer structure; make the required circuit pattern on the outer layer copper foil, use photolithography process to transfer the designed circuit pattern to the copper foil, and remove the copper not protected by photoresist to form the circuit pattern. After obtaining the circuit pattern, subsequent drilling processing can be performed.

[0051] S200, determining the parameter condition of the printed circuit board, and determining the diameter, depth and number of stages of the blind hole to be processed on the printed circuit board; the number of stages of the blind hole of the application can be defined according to the number of layers it passes through. For example, a PCB with one layer of blind hole connecting two layers of lines can be called two-stage blind hole.

[0052] Specifically, the parameter condition of the printed circuit board includes the number of layers, structure and thickness of the printed circuit board; wherein the structure includes copper in the inner layer and no copper in the inner layer; the thickness includes the thickness of the copper foil of each layer of the printed circuit board and the thickness of the substrate layer.

[0053] The increase in the number of layers of the PCB increases the complexity of laser drilling. The increase in the number of layers increases the total thickness of the material that the laser needs to penetrate, which can require higher laser power, slower scanning speed, and more processing times to ensure the integrity and consistency of the drilling.

[0054] When the inner core board contains a copper foil, the laser needs to penetrate the copper foil and the substrate layer to form a blind hole. The absorption rate of the copper foil to the laser affects the speed and quality of the drilling. Generally, the copper foil needs enough energy to be penetrated, but too high energy can cause excessive thermal influence or damage to the substrate layer under the copper foil. In addition, there can be thermal stress concentration at the interface between the copper foil and the substrate layer, causing cracks or delamination at the edge of the drilled hole.

[0055] When laser drilling is performed on the inner layer without a copper foil, the laser mainly acts on the substrate layer, and the processing process is relatively simple. However, due to the different material properties of the substrate layer (such as resin, glass fiber, etc.) from the copper foil, the interaction between the laser and the substrate will also change. The absorption rate, thermal conductivity, and other properties of the substrate layer to the laser affect the accuracy and quality of the drilling. Some substrate layers can be more susceptible to thermal damage or produce debris.

[0056] The thickness of the copper foil directly affects the energy and time required for laser drilling. Thicker copper foils require more energy to be penetrated, which can cause longer processing times or the need for higher laser power. Excessively thick copper foils can also cause thermal influence zones at the edge of the drilled hole, affecting the quality of the drilling. The thickness of the substrate layer determines the total distance that the laser needs to penetrate, which in turn affects the accuracy and speed of the drilling. Thicker substrate layers can require longer processing times and higher laser power. The material properties of the substrate layer (such as the type of resin, the content of glass fiber, etc.) also affect the effectiveness of laser drilling. Some substrate layers can absorb more laser energy, causing the thermal influence zone to expand or producing more debris.

[0057] Therefore, in the present embodiment, the number of layers, structure, and thickness of the printed circuit board need to be considered to determine the subsequent laser processing parameters.

[0058] S300, determining laser processing parameters according to the parameters of the printed circuit board, the diameter, depth, and order of the blind hole to be processed;

[0059] Further, the laser processing parameters include laser type, laser power, repetition frequency, processing times, scanning speed, filling path, and spacing; wherein the filling path includes any one or a combination of several of concentric circle filling, spiral line filling, snake shape filling, grid filling, or ring type filling.

[0060] And in the process of processing the blind hole, the filling path and the spacing are changed according to the effect of the blind hole processing.

[0061] Different laser types will affect the processing effect of blind holes. The laser type of the present application is ultrafast laser (such as picosecond or femtosecond laser). Ultrafast laser is particularly suitable for processing small diameter and high order blind holes, because it can provide finer processing capability and smaller heat-affected zone. Specifically, the pulse width of the ultrafast laser of the present application is less than 1 nanosecond (10 -9 seconds).

[0062] The laser processing parameters also include:

[0063] Laser spot size: When laser processing, the size of the spot needs to be smaller than the diameter of the blind hole to ensure the accuracy and edge quality of the drilling. For example, an ultrafast laser with a spot size of about 20-40 microns is used to process a blind hole with a hole diameter of 100 microns. Therefore, smaller blind hole diameters require the focusing system of the laser to provide smaller spots.

[0064] Laser power: The smaller the diameter of the blind hole, the higher the required laser power density is needed to provide sufficient energy to penetrate the material in a limited area. Therefore, when processing small diameter blind holes, it is necessary to increase the laser power or optimize the beam quality to increase the power density.

[0065] Scanning speed and repetition frequency: Smaller blind hole diameters require lower laser scanning speeds to increase energy input, or higher laser pulse repetition frequencies to increase energy deposition per unit time to ensure complete penetration of the drilling.

[0066] Fill path and pitch: The choice of fill path depends on the diameter, depth and order of the blind hole. Small diameter blind holes can use concentric circle filling, while larger diameter or specific shape blind holes use spiral filling or serpentine filling. High order blind holes require more complex fill paths, such as grid filling, to ensure that all layers are uniformly processed.

[0067] Focus position: For high order blind holes, the focus position may need to be adjusted to meet the processing needs of different depths, especially during the processing process, the focus may need to be moved downward to improve the hole taper problem.

[0068] S400, according to the determined laser processing parameters, using a target laser to process a blind hole on a printed circuit board without pretreatment;

[0069] S500, filling and plating the processed blind hole and subsequent process treatment;

[0070] Wherein the target laser pulse width is less than 10 picoseconds and belongs to the ultraviolet band.

[0071] The present application uses ultrafast laser with pulse width less than 10 picoseconds to process the circuit board once. Because of its extremely high peak power and extremely short action time, the ultrafast laser is much smaller than the heat diffusion time, so it can directly process high-quality multi-stage blind holes without pre-processing. This can overcome the complex steps of pre-processing such as copper reduction, brown oxidation or etching window opening before the existing CO2 laser processing.

[0072] The above-mentioned method for processing a multi-stage blind hole printed circuit board, the method comprising: obtaining a printed circuit board; determining the parameter conditions of the printed circuit board, and determining the diameter, depth and number of stages of the blind hole to be processed on the printed circuit board; determining the laser processing parameters according to the parameter conditions of the printed circuit board, the diameter, depth and number of stages of the blind hole to be processed; using target laser to process the blind hole on the printed circuit board once without pre-processing according to the determined laser processing parameters; filling the processed blind hole with electroplating and subsequent process treatment; wherein the pulse width of the target laser is less than 10 picoseconds and belongs to the ultraviolet band. This method obtains the parameter conditions of the entire circuit board, uses laser to process blind holes on the circuit board once, and uses ultrafast laser with pulse width less than 10 picoseconds, which reduces the thermal influence on the surrounding material, so that high-quality multi-stage blind holes can be directly processed without pre-processing, ensuring accurate processing of blind holes and improving processing quality and efficiency. This method can complete the processing of multi-stage blind holes at one time, avoiding multiple processing and complex process flow, thereby greatly improving the production efficiency of the circuit board. This not only shortens the production cycle, but also reduces the production cost. Due to the simplification of the processing process, the possibility of human error and process fluctuation is also reduced, further ensuring the production quality of the circuit board.

[0073] Embodiment 2

[0074] This embodiment is an improvement of embodiment 1

[0075] As Figure 2 shown in this embodiment, after processing the blind hole on the printed circuit board once, and before filling the processed blind hole with electroplating, it further comprises:

[0076] S410, obtaining the processing effect of the processed blind hole; specifically, after processing the blind hole on the entire board once, the processing effect of each blind hole is detected. The detection content includes:

[0077] whether there is resin residue in the blind hole.

[0078] whether the bottom copper of the blind hole is damaged.

[0079] whether the diameter, depth, roundness and taper of the blind hole exceed the set threshold.

[0080] S420, judging whether the processed blind hole needs to be processed again according to the processing effect of the blind hole.

[0081] More specifically, the judging whether the processed blind hole needs to be processed again according to the processing effect of the blind hole comprises:

[0082] If there is resin remaining in the blind hole, the processed blind hole is processed again to remove the remaining resin.

[0083] Wherein, when processed again, the laser processing parameters need to be adjusted to avoid damage to the bottom copper.

[0084] More specifically, if the bottom copper of the blind hole is damaged during the first processing, the laser processing parameters during the first processing are adjusted; wherein, adjusting the laser processing parameters during the first processing comprises reducing the laser frequency and reducing the processing times.

[0085] When processed again, appropriately reducing the laser power can reduce the thermal damage and mechanical impact on the bottom copper layer, thereby avoiding damage to the bottom copper. Reducing the repetition frequency of the laser can reduce the number of actions of the laser on the material per unit time, reduce heat accumulation, and reduce damage to the bottom copper layer.

[0086] Further, reducing the scanning speed can increase the action time of the laser on each point, improve the material removal efficiency, and reduce the thermal damage to the bottom copper layer. In addition, the filling path can be optimized according to the specific defect situation of the blind hole, such as using a finer spiral line filling or a snake-shaped filling to more evenly distribute the laser energy.

[0087] Further, if the taper of the blind hole exceeds the set threshold value during the first processing, the laser processing parameters are reduced to focus on processing.

[0088] Since the laser is focused on the material surface through the lens, the material is removed by absorbing energy, and when the processing reaches a certain depth, the laser is in a defocusing state, the energy is weakened, and since the laser energy is in a Gaussian distribution, the blind hole is tapered when it reaches a certain state. Therefore, by processing in multiple times, the position of the focus point is appropriately moved downward during the second processing, thereby improving the problem of hole taper.

[0089] For example, the threshold value of the taper of the blind hole of the present application is ±1 degree to ±2 degrees. If the taper of the processed blind hole exceeds the threshold value, it means that the laser focus point is too high relative to the depth of the hole. By moving the laser focus point downward, i.e. moving it inward, the laser energy can be more concentrated in the deep part of the hole, thereby reducing the inclination of the hole wall.

[0090] Ideally, in addition to adjusting the focal spot position, other laser parameters, such as power, frequency, and scanning speed, need to be optimized to ensure effective material removal even after the focal spot shifts downwards. In practical applications, an adaptive control system is used to monitor the perpendicularity of the hole wall in real time and dynamically adjust the position of the laser focal spot to keep the taper of the hole wall within a controlled range.

[0091] Example 3

[0092] This embodiment provides a circuit board, which is manufactured using the multi-level blind via printed circuit board processing method described above;

[0093] The circuit board includes a multilayer core board. During the manufacturing process, the core boards with completed circuit patterns are pre-stacked according to design requirements, and then the whole board is pressed together to obtain the circuit board.

[0094] like Figures 3-4 As shown, the manufacturing process of this circuit board is as follows:

[0095] Prepare a multilayer core board, with the required circuit patterns fabricated on each layer.

[0096] Pre-stacking: According to design requirements, the core boards of each layer are pre-stacked in a specific order and position to ensure the alignment accuracy between the layers.

[0097] Lamination: The pre-stacked core boards are pressed together and cured to form a circuit board. During the lamination process, appropriate temperature, pressure, and time parameters are used to ensure the strong bonding between layers and the overall performance of the circuit board.

[0098] Multi-stage blind via processing: The multi-stage blind via processing method described in the above embodiments is used to process blind vias on circuit boards. This includes using ultrafast laser technology for one-time multi-stage blind via processing, eliminating the need for pretreatment and improving processing efficiency and quality. No browning or etching is required for opening windows.

[0099] Subsequent processing: After completing the blind hole processing, subsequent processes such as hole filling electroplating and outer layer pattern making are carried out to complete the circuit board manufacturing.

[0100] This circuit board utilizes ultrafast laser technology for blind via processing, reducing the need for multiple drilling and electroplating steps in traditional methods and significantly improving production efficiency. It avoids issues such as hole wall damage and heat-affected zones that can occur in traditional processing, ensuring the quality of the blind vias. The simplified production process reduces material and labor costs, contributing to lower overall production costs. High-density interconnects and high-quality blind via processing enhance the electrical performance and reliability of the circuit board, extending product lifespan.

[0101] In addition, it should be noted that the use of "first", "second", and the like words to qualify elements is merely intended to distinguish the respective elements from one another, and such words do not have special meanings unless otherwise stated. Therefore, they cannot be understood as limiting the scope of protection of the present application.

[0102] The preferred embodiments of the present application have been described above with the aid of drawing figures, and are not intended to limit the present application, and for those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A method of processing a multi-step blind via printed circuit board, characterized by, The method comprises the following steps: obtaining a printed circuit board; determining the parameter condition of the printed circuit board, and determining the diameter, depth and order of the blind hole to be processed on the printed circuit board; determining the laser processing parameters according to the parameter condition of the printed circuit board, the diameter, depth and order of the blind hole to be processed; processing the multi-order blind hole on the printed circuit board without pre-treatment by using a target laser according to the determined laser processing parameters; filling the processed blind hole with electroplating and subsequent process treatment; wherein the target laser pulse width is less than 10 picoseconds and belongs to the ultraviolet wave band.

2. The method according to claim 1, wherein after processing the blind hole on the printed circuit board once and before filling the processed blind hole with electroplating, the method further comprises the following steps: obtaining the processing effect of the processed blind hole; determining whether the processed blind hole needs to be processed again according to the processing effect of the blind hole.

3. The method according to claim 2, wherein the processing effect of the blind hole comprises: whether there is resin remaining in the blind hole; whether the bottom copper of the blind hole is damaged; whether the diameter, depth, roundness and taper of the blind hole exceed the set threshold.

4. The method according to claim 3, wherein the step of determining whether the processed blind hole needs to be processed again according to the processing effect of the blind hole comprises: if there is resin remaining in the blind hole, processing the processed blind hole again; wherein the laser processing parameters need to be adjusted during the second processing to avoid damage to the low copper.

5. The method according to claim 3, wherein if the bottom copper of the blind hole is damaged during the first processing, the laser processing parameters during the first processing are adjusted; wherein the adjustment of the laser processing parameters during the first processing comprises reducing the laser frequency and the processing times.

6. The method according to claim 3, wherein if the taper of the blind hole exceeds the set threshold during the first processing, the focus of the laser processing parameters is lowered for processing.

7. The method according to any one of claims 1-6, wherein the parameter condition of the printed circuit board comprises the number of layers, structure and thickness of the printed circuit board; wherein the structure comprises copper in the inner layer and no copper in the inner layer of the printed circuit board; and the thickness comprises the thickness of the copper foil of each layer and the thickness of the substrate layer of the printed circuit board.

8. The method according to claim 1, wherein the laser processing parameters comprise the type of laser, laser power, repetition frequency, processing times, scanning speed, filling path and spacing; wherein the filling path comprises any one or a combination of several paths of concentric circle filling, spiral line filling or serpentine filling; and the filling path and spacing are changed according to the processing effect of the blind hole during the processing of the blind hole. The method is used for the production of the multi-order blind hole printed circuit board according to any one of claims 1-6. ​ ​ ​ ​ ​ ​ 9. A circuit board, characterized by: ​ The circuit board comprises a plurality of core boards, and each core board with completed circuit pattern is pre-laminated according to design requirements in a manufacturing process, and then the printed circuit board is obtained by overall pressing.

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