Back drilling processing method for circuit board via hole, back drilling processing device and circuit board

Abstract

The embodiment of the present invention discloses a back drilling processing method, a back drilling processing device and a circuit board for via holes of a circuit board. The back drilling processing method includes: first determining the positioning holes of the circuit board, and performing a drilling process on the positioning holes to obtain via hole slices; then determining the thickness scaling ratio in the actual production process of the circuit board according to the via hole slices; then outputting the back drilling tape of each positioning hole according to the thickness scaling ratio; finally, performing back drilling positioning according to the back drilling tape and using each positioning hole to process the back drilled holes. The above method can be used to explore the variation law of the thickness of each layer of the laminated circuit board medium, provide a high-precision back drilling residual pile control method for thick and multi-layer circuit boards, reduce the use of the back drilling machine surveying and mapping function, improve the utilization rate of the back drilling machine, improve the production efficiency of the back drilling processing of the circuit board via holes, and reduce the production cost, realize the batch stable control of high-precision back drilling residual piles, and speed up the production cycle.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of circuit board manufacturing, and in particular to a back drilling processing method for a circuit board via hole, a back drilling processing device and a circuit board. Background Art

[0002] In the field of high-speed printed circuit boards (PCBs), when the signal frequency reaches a certain frequency, such as above 1 GHz, the signal transmission line on the PCB is at the via position. Due to the impedance matching of the via itself and the capacitance of the via, the electrical signal energy will be greatly lost during the transmission process of the via. In order to reduce this loss, the via stub can be back-drilled. Generally, in the signal transmission topology with a transmission speed of PCIe5.0, the back-drill stub is required to be controlled at 2 to 10 mils.

[0003] In order to achieve a relatively high signal transmission quality at the via position on a high-layer board, the invalid stumps after the via back drilling will be reduced as much as possible. However, when the board thickness becomes thicker, the tolerance of the via stump is particularly affected by the uneven board thickness. Therefore, it is necessary to find a via stump that can still achieve high accuracy in the case of thicker boards. The industry generally uses the mapping function of the automatic measurement (CCD) back drilling machine to achieve this goal. However, because the use of the mapping function will affect the utilization rate of the back drilling machine, it is very uneconomical. Summary of the invention

[0004] The embodiments of the present invention provide a back drilling processing method, a back drilling processing device and a circuit board for a circuit board via hole, so as to explore the variation law of the dielectric thickness of each layer of the circuit board after lamination, provide a high-precision back drilling residual pile control method, improve the utilization rate of the back drilling machine, and improve production efficiency.

[0005] In a first aspect, an embodiment of the present invention provides a back drilling method for a circuit board via hole, comprising:

[0006] Determine the positioning holes of the circuit board, and perform a drilling process on the positioning holes to obtain via slices;

[0007] Determining a thickness scaling ratio in an actual production process of the circuit board according to the via slices;

[0008] outputting the back-drilling drill belt of each of the positioning holes according to the thickness scaling ratio;

[0009] According to the back-drilling drill belt, back-drilling positioning is performed by utilizing each of the positioning holes to machine back-drilled holes.

[0010] Optionally, determining the thickness scaling ratio of the circuit board in an actual production process according to the via slicing includes:

[0011] Obtaining a measured thickness and a designed thickness of at least a portion of the stacked structure in the via slice;

[0012] The thickness scaling ratio in the actual production process of the circuit board is determined according to the ratio of the measured thickness of at least part of the stacked structure in the via slice to the designed thickness.

[0013] Optionally, the circuit board comprises at least one laminated copper conductor layer, at least one prepreg layer and at least one core layer;

[0014] Obtaining a measured thickness and a designed thickness of at least a portion of the stacked structure in the via slice, comprising:

[0015] Obtaining a first measured thickness and a first designed thickness of the via slice, wherein the first measured thickness is the sum of the thickness of all copper conductor layers, the thickness of all prepreg layers, and the thickness of all core layers between the back side of the via slice and the target reference layer, and the first designed thickness is the sum of the designed thickness of all copper conductor layers, the designed thickness of all prepreg layers, and the designed thickness of all core layers between the back side of the via slice and the target reference layer; wherein the target reference layer is a core layer or a prepreg layer;

[0016] Determining a thickness scaling ratio in an actual production process of the circuit board according to a ratio of a measured thickness of at least a portion of the stacked structure in the via slice to a designed thickness includes:

[0017] A ratio of the first measured thickness to the first designed thickness is calculated as a thickness scaling ratio in an actual production process of the circuit board.

[0018] Optionally, outputting a back-drilling tape of each of the positioning holes according to the thickness scaling ratio comprises:

[0019] Obtaining the designed thickness of the target reference layer;

[0020] The product of the thickness scaling ratio and the design thickness of the target reference layer is calculated to obtain the backdrilling depth of each of the positioning holes, and to form the backdrilling drill belt.

[0021] Optionally, obtaining a first measured thickness of the via slice includes:

[0022] Measuring the thickness of the copper conductor layer multiple times and taking an average value to obtain an average thickness of the copper conductor layer;

[0023] Measuring the thickness of the prepreg layer multiple times and taking an average value to obtain an average thickness of the prepreg layer;

[0024] Measuring the thickness of the core plate layer multiple times and taking an average value to obtain an average thickness of the core plate layer;

[0025] The sum of the average thickness of all the copper conductor layers between the back side and the target reference layer in the via slice, the average thickness of all the prepreg layers, and the average thickness of all the core board layers is calculated as the first measured thickness of the via slice.

[0026] Optionally, obtaining a first design thickness of the via slice includes:

[0027] Obtaining the designed thickness of the copper conductor layer, the designed thickness of the prepreg layer and the designed thickness of the core board layer;

[0028] The sum of the design thickness of all the copper conductor layers between the back side and the target reference layer in the via slice, the design thickness of all the prepreg layers, and the design thickness of all the core board layers is calculated as the first design thickness of the via slice.

[0029] In a second aspect, an embodiment of the present invention further provides a back drilling processing device for a circuit board via hole, comprising:

[0030] A drilling module is used to determine the positioning holes of the circuit board and perform a drilling process on the positioning holes to obtain via slices;

[0031] A scaling ratio determination module, used to determine the thickness scaling ratio of the circuit board in the actual production process according to the via slices;

[0032] A drill belt generation module, used for outputting a back drill belt of each positioning hole according to the thickness scaling ratio;

[0033] The back drilling module is used to perform back drilling positioning according to the back drilling belt and utilize each of the positioning holes to process back drilling holes.

[0034] Optionally, the scaling ratio determination module includes:

[0035] A thickness acquisition unit, used to acquire a measured thickness and a designed thickness of at least a portion of the stacked structure in the via slice;

[0036] The scaling ratio calculation unit is used to determine the thickness scaling ratio in the actual production process of the circuit board according to the ratio of the measured thickness of at least part of the stacked structure in the via slice to the designed thickness.

[0037] Optionally, the circuit board comprises at least one laminated copper conductor layer, at least one prepreg layer and at least one core layer;

[0038] The thickness acquisition unit includes a thickness acquisition subunit, and the thickness acquisition subunit is used to acquire a first measured thickness and a first designed thickness of the via slice, wherein the first measured thickness is the sum of the thickness of all copper conductor layers, the thickness of all prepreg layers, and the thickness of all core layers between the back side of the via slice and the target reference layer, and the first designed thickness is the sum of the designed thickness of all copper conductor layers, the designed thickness of all prepreg layers, and the designed thickness of all core layers between the back side of the via slice and the target reference layer; wherein the target reference layer is a core layer or a prepreg layer;

[0039] The scaling ratio calculation unit includes a scaling ratio calculation subunit, and the scaling ratio calculation subunit is used to calculate the ratio of the first measured thickness to the first designed thickness as the thickness scaling ratio in the actual production process of the circuit board.

[0040] In a third aspect, an embodiment of the present invention further provides a circuit board, which is prepared using the back drilling processing method for a circuit board via hole as described in any one of the first aspects.

[0041] The embodiment of the present invention provides a back drilling processing method, a back drilling processing device and a circuit board for via holes of a circuit board. The back drilling processing method includes: firstly determining the positioning holes of the circuit board, and performing a drilling process on the positioning holes to obtain via hole slices; then determining the thickness scaling ratio in the actual production process of the circuit board according to the via hole slices; then outputting the back drilling tape of each positioning hole according to the thickness scaling ratio; finally, performing back drilling positioning according to the back drilling tape and using each positioning hole to process the back drilled holes. The above method can be used to explore the variation law of the thickness of each layer of the laminated circuit board medium, and provide a high-precision back drilling residual pile control method for thick and multi-layer circuit boards, reduce the use of the mapping function of the back drilling machine, improve the utilization rate of the back drilling machine, improve the production efficiency of the back drilling processing of the circuit board via holes, and reduce the production cost, realize the batch stable control of high-precision back drilling residual piles, and speed up the production cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 is a cross-sectional schematic diagram of a back drilling process of a circuit board via hole provided by an embodiment of the present invention;

[0044] Figure 2It is a schematic flow chart of a back drilling method for a circuit board via provided by an embodiment of the present invention;

[0045] Figure 3 It is a schematic flow chart of another back drilling processing method for a circuit board via hole provided by an embodiment of the present invention;

[0046] Figure 4 It is a schematic flow chart of another back drilling method for a circuit board via provided by an embodiment of the present invention;

[0047] Figure 5 It is a structural schematic diagram of a back drilling processing device for a circuit board via hole provided by an embodiment of the present invention;

[0048] Figure 6 It is a schematic diagram of the structure of a circuit board provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0050] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. It should be noted that the directional words such as "upper", "lower", "left", "right" and the like described in the embodiments of the present invention are described at the angles shown in the accompanying drawings and should not be understood as limitations on the embodiments of the present invention. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is formed "on" or "under" another element, it can not only be directly formed "on" or "under" another element, but also indirectly formed "on" or "under" another element through an intermediate element. The terms "first", "second", etc. are only used for descriptive purposes and do not represent any order, quantity or importance, but are only used to distinguish different components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0051] The term “including” and its variations used in the present invention are open inclusions, that is, “including but not limited to.” The term “based on” means “based at least in part on.” The term “one embodiment” means “at least one embodiment.”

[0052] It should be noted that the concepts such as "first" and "second" mentioned in the present invention are only used to distinguish the corresponding contents, and are not used to limit the order or interdependence.

[0053] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0054] Figure 1 is a cross-sectional schematic diagram of a back drilling process of a circuit board via hole provided by an embodiment of the present invention, Figure 2 This is a flow chart of a back drilling method for a circuit board via provided by an embodiment of the present invention. This embodiment is applicable to application scenarios where a circuit board needs to have a back drilling via. The back drilling method can be performed by a back drilling device for a circuit board via. The back drilling device can be implemented in the form of software and / or hardware. The back drilling device can be configured in a control board. Figure 1 and Figure 2 As shown, the back drilling method includes:

[0055] S110, determining the positioning holes of the circuit board, and drilling the positioning holes to obtain via slices.

[0056] Specifically, continue to refer to Figure 1 In the process of circuit board manufacturing, positioning holes are provided on the circuit board. The positioning holes can be used to position the circuit board with one drill and drill holes with one drill. The through holes processed by one drill need to be copper plated to form a conductive layer to achieve electrical connection between the inner circuit boards. Via slices can be obtained through one drill drilling and nine-point slicing method. Among them, the nine-point slicing method is to locate at the drilling position with 3×3 positioning points and obtain via slices.

[0057] S120. Determine the thickness scaling ratio in the actual production process of the circuit board according to the via slices.

[0058] Specifically, continue to refer to Figure 1 According to the one-drilling processing of the positioning holes of the circuit board and the via slices obtained by the nine-point slicing method, due to the press forming and other operations of the circuit board in the actual generation process, there is a difference between the thickness parameters of the circuit board in the design process and the thickness parameters after the circuit board is manufactured, and there is a proportional relationship between the thickness parameters of the circuit board in the design process and the thickness parameters after the circuit board is manufactured, and the thickness parameters of the circuit board in the design process are greater than or equal to the thickness parameters after the circuit board is manufactured. The thickness parameters of the circuit board after the completion of the production can be determined according to the via slices, and compared with the thickness parameters of the circuit board in the design process, the thickness scaling ratio of the circuit board in the actual production process can be determined.

[0059] S130, outputting the back drill tape of each positioning hole according to the thickness scaling ratio.

[0060] Specifically, continue to refer to Figure 1 According to the via slices, the thickness parameters of the circuit board after production can be determined. By comparing with the thickness parameters of the circuit board during the design process, the thickness scaling ratio of the circuit board during actual production can be determined. By exploring the law of the difference in thickness parameters of the circuit board during actual production, that is, according to the thickness scaling ratio, different back drill tape information is determined for the thickness parameters at different via positions, where the back drill tape includes the back drill position information and back drill depth information of the vias that need to be back drilled.

[0061] S140, performing back drilling positioning according to the back drilling drill belt and utilizing the positioning holes to machine the back drilling holes.

[0062] Specifically, continue to refer to Figure 1 , use the positioning hole used for the first drilling process to perform back drilling positioning, and use a drill to back drill the electroplated holes that need to be back drilled. The function of back drilling is to drill out the through-hole sections that do not play any connection or transmission role, so as to avoid reflection, scattering, delay, etc. of signal transmission, which will cause "distortion" to the signal. It is necessary to use back drilling to minimize the signal loss caused by the impedance matching or capacitance of the via itself during the transmission of the electrical signal energy at the via position, which can reduce the size of the back drilling stump and improve the high-precision control of the back drilling stump.

[0063] The technical solution in the embodiment of the present invention first determines the positioning holes of the circuit board, and performs a drilling process on the positioning holes to obtain via slices; then, according to the via slices, determines the thickness scaling ratio in the actual production process of the circuit board; then, according to the thickness scaling ratio, outputs the back drill tape of each positioning hole; finally, according to the back drill tape, back drill positioning is performed using each positioning hole to process the back drill hole. Using the above method, the variation law of the thickness of each layer of the laminated circuit board medium can be explored, and a high-precision back drill residual pile control method for thick and multi-layer circuit boards is provided, which reduces the use of the mapping function of the back drill machine, improves the utilization rate of the back drill machine, improves the production efficiency of the back drill processing of the circuit board via, and reduces the production cost, realizes the batch stable control of high-precision back drill residual piles, and speeds up the production cycle.

[0064] Table 1 is a schematic table of the design thickness and measured thickness of each stacked structure of a circuit board via slice provided by an embodiment of the present invention. Figure 3 1 is a flow chart of another back drilling method for a circuit board via provided by an embodiment of the present invention. This embodiment is optimized on the basis of the above embodiment. Optionally, according to the via slicing, the thickness scaling ratio in the actual production process of the circuit board is determined, including:

[0065] Obtaining a measured thickness and a designed thickness of at least a portion of a stacked structure in a via slice;

[0066] The thickness scaling ratio in the actual production process of the circuit board is determined according to the ratio of the measured thickness of at least a portion of the stacked structure in the via slice to the designed thickness.

[0067] Table 1

[0068]

[0069]

[0070] Please refer to the above embodiments for details that are not yet fully described in this embodiment. Figure 3 As shown, the back drilling method includes:

[0071] S210, determining the positioning holes of the circuit board, and drilling the positioning holes to obtain via slices.

[0072] S220, obtaining a measured thickness and a designed thickness of at least a portion of the stacked structure in the via slice.

[0073] Optionally, continue to refer to Table 1 and Figure 1 The circuit board includes at least one copper conductor layer 1, at least one prepreg layer 2 and at least one core board layer 3 stacked together; obtaining the measured thickness and designed thickness of at least part of the stacked structure in the via slice, including: obtaining the first measured thickness and the first designed thickness of the via slice, wherein the first measured thickness is the sum of the thickness of all copper conductor layers 1, the thickness of all prepreg layers 2 and the thickness of all core board layers 3 between the back side of the via slice and the target reference layer, and the first designed thickness is the sum of the designed thickness of all copper conductor layers 1, the design thickness of all prepreg layers 2 and the design thickness of all core board layers 3 between the back side of the via slice and the target reference layer; wherein the target reference layer is the core board layer 3 or the prepreg layer 2.

[0074] Specifically, the copper conductor layer 1 can serve as an electrical connection between the inner circuit boards, the prepreg layer 2 can serve as a filler, and the core board layer 3 can serve as a conductor, an insulator, and a support. The circuit board includes at least one copper conductor layer 1, at least one prepreg layer 2, and at least one core board layer 3 stacked in layers, as shown in Tables 1 and Figure 1As shown, the circuit board may be composed of a copper conductor layer 11, a prepreg layer 21, a copper conductor layer 12, a core layer 31, a copper conductor layer 13, a prepreg layer 22, a copper conductor layer 14, a core layer 32, a copper conductor layer 15, a prepreg layer 23 and a copper conductor layer 16 stacked from top to bottom. The measured thickness and the designed thickness of at least part of the stacked structure in the via slice are obtained, wherein at least part of the stacked structure is the thickness parameter from the back side to the target reference layer in the via slice, that is, from the upper surface layer of the back-drilled hole to the last drilling surface layer of the back-drilled hole. For example, if the back-drilled hole needs to be back-drilled from the copper conductor layer 11 to the core layer 31, the copper conductor layer 11 is the upper surface layer of the back-drilled hole, and the core layer 31 is the last drilling surface layer of the back-drilled hole; if the back-drilled hole needs to be back-drilled from the copper conductor layer 11 to the core layer 32, the copper conductor layer 11 is the upper surface layer of the back-drilled hole, and the core layer 32 is the last drilling surface layer of the back-drilled hole. It should be noted that the target reference layer, or the last drilling surface layer of the back drilling hole, can be the core board layer 3 or the semi-cured sheet layer 2, but cannot be the copper conductor layer 1. The copper conductor layer 1 is located between the adjacent semi-cured sheet layer 2 and the core board layer 3. The thickness of the copper conductor layer 1 is very small compared to the thickness of the semi-cured sheet layer 2 and the thickness of the core board layer 3. During the back drilling process, the copper conductor layer 1 cannot be accurately back drilled, but the core board layer 3 or the semi-cured sheet layer 2 is used as the last drilling surface layer of the back drilling hole. This is just an example and is not limited. The back drilling hole can also be back drilled from the copper conductor layer 11 to the semi-cured sheet layer 21, then the copper conductor layer 11 is the upper surface layer of the back drilling hole, and the semi-cured sheet layer 21 is the last drilling surface layer of the back drilling hole; the back drilling hole can also be back drilled from the copper conductor layer 11 to the semi-cured sheet layer 22, then the copper conductor layer 11 is the upper surface layer of the back drilling hole, and the semi-cured sheet layer 22 is the last drilling surface layer of the back drilling hole.

[0075] Further, continue to refer to Table 1 and Figure 1 , obtaining the first measured thickness of the via slice, including: measuring the thickness of the copper conductor layer 1 multiple times and taking the average value to obtain the average thickness of the copper conductor layer 1; measuring the thickness of the prepreg layer 2 multiple times and taking the average value to obtain the average thickness of the prepreg layer 2; measuring the thickness of the core board layer 3 multiple times and taking the average value to obtain the average thickness of the core board layer 3; calculating the sum of the average thickness of all copper conductor layers 1 between the back side and the target reference layer in the via slice, the thickness of all prepreg layers 2, and the thickness of all core board layers 3 as the first measured thickness of the via slice.

[0076] Specifically, the thickness of the same copper conductor layer 1 can be measured multiple times by the mapping function of the automatic measurement (CCD) back drill, and the thickness values ​​obtained by the multiple measurements are added up and averaged to obtain the average thickness of the copper conductor layer 1. By way of example, the thickness of the same copper conductor layer 1 can also be measured multiple times by other measuring tools. This is just an example and is not limited here. Similarly, the thickness values ​​of the same semi-cured sheet layer 2 can be measured multiple times by the mapping function of the automatic measurement (CCD) back drill, and the thickness values ​​are added up and averaged to obtain the average thickness of the semi-cured sheet layer 2. The thickness values ​​of the core board layer 3 can be measured multiple times by the mapping function of the automatic measurement (CCD) back drill, and the thickness values ​​are added up and averaged to obtain the average thickness of the core board layer 3. After obtaining the average thickness of each copper conductor layer 1, each prepreg layer 2, and each core board layer 3, the average thickness of all copper conductor layers 1, the average thickness of all prepreg layers 2, and the average thickness of all core board layers 3 between the upper surface layer of the back-drilled hole to be back-drilled in the via corresponding to the via slice are calculated as the first measured thickness of the via slice. For example, if the back-drilled hole needs to be back-drilled from the copper conductor layer 11 to the core board layer 31, the first measured thickness is the average thickness of the copper conductor layer 11, the average thickness of the prepreg layer 21, and the average thickness of the copper conductor layer 12. and the average thickness of the core board layer 31, that is, the first measured thickness at this time is A'+B'+C'+D'; if the back drilling needs to be back-drilled from the copper conductor layer 11 to the core board layer 32, the first measured thickness is the average thickness of the copper conductor layer 11, the average thickness of the semi-cured sheet layer 21, the average thickness of the copper conductor layer 12, the average thickness of the core board layer 31, the average thickness of the copper conductor layer 13, the average thickness of the semi-cured sheet layer 22, the average thickness of the copper conductor layer 14 and the average thickness of the core board layer 32, that is, the first measured thickness at this time is A'+B'+C'+D'+E'+F'+G'+H'. It should be noted that due to the thickness change during the circuit board manufacturing and pressing process, the copper conductor layer 1 on the same layer may have different thicknesses at different positions. Therefore, the average thicknesses of the copper conductor layer 11, the copper conductor layer 12 and the copper conductor layer 13 may be different and not equal, and the average thicknesses of the semi-cured sheet layer 21, the semi-cured sheet layer 22 and the semi-cured sheet layer 23 may also be different, and the average thicknesses of the core board layer 31 and the core board layer 32 may also be different.

[0077] Further, referring to Table 1 and Figure 1, obtaining the first design thickness of the via slice, including: obtaining the design thickness of the copper conductor layer 1, the design thickness of the prepreg layer 2 and the design thickness of the core board layer 3; calculating the sum of the design thickness of all copper conductor layers 1, the design thickness of all prepreg layers 2 and the design thickness of all core board layers 3 between the back side and the target reference layer in the via slice as the first design thickness of the via slice.

[0078] Specifically, in the process of manufacturing the circuit board, by setting the design thickness of each stacked structure, the design thickness of each copper conductor layer 1, the design thickness of each prepreg layer 2, and the design thickness of each core board layer 3 can be obtained. After the design thickness of each copper conductor layer 1, each prepreg layer 2, and each core board layer 3 is obtained, the sum of the design thickness of all copper conductor layers 1, the design thickness of all prepreg layers 2, and the design thickness of all core board layers 3 between the upper surface layer of the back-drilled hole to be back-drilled in the via corresponding to the via slice is calculated as the first design thickness of the via slice. For example, if the back-drilled hole needs to be back-drilled from the copper conductor layer 11 to the core board layer 31, the first design thickness is the design thickness of the copper conductor layer 11, the design thickness of the prepreg layer 21, the design thickness of the copper conductor layer 11, the design thickness of the prepreg layer 21, the design thickness of the copper conductor layer 11, and the design thickness of the core board layer 3. 2 and the design thickness of the core board layer 31, that is, the first design thickness is A+B+C+D at this time; if the back drilling needs to be back-drilled from the copper conductor layer 11 to the core board layer 32, the first design thickness is the sum of the design thickness of the copper conductor layer 11, the design thickness of the semi-cured sheet layer 21, the design thickness of the copper conductor layer 12, the design thickness of the core board layer 31, the design thickness of the copper conductor layer 13, the design thickness of the semi-cured sheet layer 22, the design thickness of the copper conductor layer 14 and the design thickness of the core board layer 32, that is, the first design thickness is A+B+C+D+E+F+G+H at this time. It should be noted that, with respect to the design thickness, it may be determined according to the actual signal transmission requirements of the circuit board. The design thicknesses of the copper conductor layer 11, the copper conductor layer 12 and the copper conductor layer 13 of different layers may be equal or unequal, and the design thicknesses of the semi-cured sheet layer 21, the semi-cured sheet layer 22 and the semi-cured sheet layer 23 may be equal or unequal, and the design thicknesses of the core board layer 31 and the core board layer 32 may be equal or unequal.

[0079] S230, determining a thickness scaling ratio in an actual production process of the circuit board according to a ratio of a measured thickness of at least a portion of the stacked structure in the via slice to a designed thickness.

[0080] Optionally, continue to refer to Table 1 and Figure 1 , according to the ratio of the measured thickness and the designed thickness of at least part of the stacked structure in the via slice, determining the thickness scaling ratio in the actual production process of the circuit board, including: calculating the ratio of the first measured thickness and the first designed thickness as the thickness scaling ratio in the actual production process of the circuit board.

[0081] Specifically, the overall thickness of the circuit board is measured multiple times through the mapping function of the automatic measurement (CCD) back drilling machine, the thickness values ​​obtained by multiple measurements are added and averaged to obtain the average thickness of the circuit board, and the average thickness of the circuit board is used as the first measured thickness, and the overall design thickness of the circuit board is used as the first design thickness. The ratio of the first measured thickness to the first design thickness is calculated, and the thickness scaling ratio of the circuit board in the actual production process can be obtained, which is used as the backdrilling depth coefficient W in the backdrilling process. However, it should be noted that the backdrilling depth coefficient W calculated at this time may have errors, and the actual backdrilling depth at the backdrilling positions of different vias may have large errors. Furthermore, in order to improve the high-precision control of the back-drilled residual piles and reduce the spatial size and thickness of the back-drilled residual piles, the measured thickness of all copper conductor layers 1 between the upper surface layer of the back-drilled hole and the last drilling surface layer of the back-drilled hole, the measured thickness of all prepreg layers 2, and the measured thickness of all core board layers 3 can be added as the first measured thickness, and the designed thickness of all copper conductor layers 1 between the upper surface layer of the back-drilled hole and the last drilling surface layer of the back-drilled hole, the designed thickness of all prepreg layers 2, and the designed thickness of all core board layers 3 can be added as the first designed thickness, and the first measured thickness and the first designed thickness at this time are calculated. The ratio of the calculated thickness can be used to obtain the thickness scaling ratio in the actual production process of the circuit board, and used as the back-drilling depth coefficient W in the back-drilling process. For example, if the back-drilling hole needs to be back-drilled from the copper conductor layer 11 to the core board layer 31, the back-drilling depth coefficient W of the back-drilling hole at position a is W = (A'+B'+C'+D') / (A+B+C+D); if the back-drilling hole needs to be back-drilled from the copper conductor layer 11 to the core board layer 32, the back-drilling depth coefficient W of the back-drilling hole at position b is W = (A'+B'+C'+D'+E'+F'+G'+H') / (A+B+C+D+E+F+G+H). It should be noted that the back-drilling depth coefficient W calculated at this time has different back-drilling depth coefficients W for different back-drilling holes, so the high-precision control of the back-drilling residual piles can be improved, and the spatial size and thickness of the back-drilling residual piles can be reduced.

[0082] S240, outputting the back drill tape of each positioning hole according to the thickness scaling ratio.

[0083] S250, performing back drilling positioning according to the back drilling drill belt and utilizing the positioning holes to machine the back drilling holes.

[0084] The technical solution in the embodiment of the present invention describes in detail the content of determining the thickness scaling ratio in the actual production process of the circuit board according to the via slice, firstly determining the positioning hole of the circuit board, and performing a drilling process on the positioning hole to obtain the via slice, then obtaining the measured thickness and the designed thickness of at least part of the stacked structure in the via slice, and then determining the thickness scaling ratio in the actual production process of the circuit board according to the ratio of the measured thickness and the designed thickness of at least part of the stacked structure in the via slice, and then outputting the back drilling tape of each positioning hole according to the thickness scaling ratio, and finally performing back drilling positioning according to the back drilling tape and using each positioning hole to process the back drilling hole. By using the above method, the variation law of the thickness parameters of each stacked structure in the circuit board is explored, and the corresponding back drilling depth coefficient is calculated for different via positions, and then in the back drilling process, the high-precision control of the back drilling residual pile can be further improved, and the back drilling effect of 2 to 8 mil can be achieved when the back drilling depth is within 100 mil, thereby improving the utilization rate of the back drilling machine and accelerating the production cycle of the back drilling process of the circuit board via.

[0085] Figure 4 1 is a flow chart of another back drilling method for a circuit board via provided by an embodiment of the present invention. This embodiment is optimized on the basis of the above embodiment. Optionally, according to the thickness scaling ratio, a back drilling tape of each positioning hole is output, including:

[0086] Obtain the design thickness of the target reference layer;

[0087] The product of the thickness scaling ratio and the design thickness of the target reference layer is calculated to obtain the backdrilling depth of each positioning hole and form a backdrilling drill belt.

[0088] For details not yet provided in this embodiment, please refer to the above embodiments. Figure 4 As shown, the back drilling method includes:

[0089] S310, determining the positioning holes of the circuit board, and drilling the positioning holes to obtain via slices.

[0090] S320, obtaining a measured thickness and a designed thickness of at least a portion of the stacked structure in the via slice.

[0091] S330, determining a thickness scaling ratio in an actual production process of the circuit board according to a ratio of a measured thickness of at least a portion of the stacked structure in the via slice to a designed thickness.

[0092] S340, obtaining the design thickness of the target reference layer.

[0093] Specifically, continue to refer to Table 1 and Figure 1In the actual back drilling process of the circuit board via, the back drilling process is performed from the upper surface layer of the back drilling hole to the last drilling surface layer of the back drilling hole. It can be known that due to the shape limitation of the drill hole of the back drilling process, the last drilling surface layer of the back drilling hole is not completely back drilled away. There may be back drilling stubs in the last drilling surface layer of the back drilling hole. The back drilling stubs will affect the signal energy transmission of the circuit board. Therefore, the spatial size of the back drilling stubs should be reduced, and the control accuracy of the back drilling stubs should be improved to achieve a back drilling effect of 2 to 8 mil when the back drilling depth is within 100 mil. Exemplarily, if the back-drilling hole needs to be back-drilled from the copper conductor layer 11 to the core board layer 31, then the first design thickness is A+B+C+D, the target reference layer is the core board layer 31, and the design thickness of the core board layer 31 is D; if the back-drilling hole needs to be back-drilled from the copper conductor layer 11 to the core board layer 32, then the first design thickness is A+B+C+D+E+F+G+H, the target reference layer is the core board layer 32, and the design thickness of the core board layer 32 is H.

[0094] S350, calculating the product of the thickness scaling ratio and the design thickness of the target reference layer, obtaining the backdrilling depth of each positioning hole, and forming a backdrilling drill belt.

[0095] The back drilling drill belt includes the back drilling position information and back drilling depth information of each back drilling hole. Figure 1 By exploring the relationship between the backdrilling depth coefficient W and the design thickness, the backdrilling depth of each positioning hole is obtained. Compared with exploring the relationship between the backdrilling depth coefficient W and the design thickness, the backdrilling depth of each positioning hole is obtained. The calculation of the design thickness can save multiple measurement processes of the backdrilling machine. After obtaining the designed thickness of the last drilling surface layer of the back-drilled hole, the product of the thickness scaling ratio (back-drilling depth coefficient W) and the designed thickness of the target reference layer (the last drilling surface layer of the back-drilled hole) is calculated to obtain the back-drilling depth of each positioning hole. For example, if the back-drilled hole needs to be back-drilled from the copper conductor layer 11 to the core board layer 31, the actual back-drilling depth of the back-drilled hole at position a is h=W×D=[(A'+B'+C'+D') / (A+B+C+D)]×D; if the back-drilled hole needs to be back-drilled from the copper conductor layer 11 to the core board layer 32, the actual back-drilling depth of the back-drilled hole at position b is h=W×H=[(A'+B'+C'+D'+E'+F'+G'+H') / (A+B+C+D+E+F+G+H)]×H. The position information of each via of the circuit board corresponds to the position information of the via that needs to be back-drilled. The back-drill depth information of each back-drilled hole can be obtained through the back-drill depth coefficient W of the back-drilled hole and the design thickness of the target reference layer. In this way, the back-drill position information and back-drill depth information of each back-drilled hole are finally obtained, that is, the back-drill drill tape information of each back-drilled hole is obtained.

[0096] S360, performing back drilling positioning according to the back drilling drill belt and utilizing each positioning hole to machine the back drilling hole.

[0097] The technical solution in the embodiment of the present invention describes in detail the content of the back drill tape of each positioning hole output according to the thickness scaling ratio. First, the positioning holes of the circuit board are determined, and the positioning holes are drilled to obtain via slices, and then the measured thickness and design thickness of at least part of the stacked structure in the via slices are obtained. Then, according to the ratio of the measured thickness and design thickness of at least part of the stacked structure in the via slices, the thickness scaling ratio in the actual production process of the circuit board is determined, and then the design thickness of the target reference layer is obtained. Then, the product of the thickness scaling ratio and the design thickness of the target reference layer is calculated to obtain the back drill depth of each positioning hole, and a back drill tape is formed. Finally, according to the back drill tape, back drill positioning is performed using each positioning hole to process the back drill holes. By using the above method, the backdrill depth of the target reference layer of the backdrilled hole is calculated through the backdrill depth coefficient corresponding to each drilled hole, so that a backdrilling effect of 2 to 8 mil can be achieved when the backdrilling depth is within 100 mil, thereby improving the high-precision control of the backdrilling residual piles, improving the utilization rate of the backdrilling machine, and accelerating the production cycle of the backdrilling process of the circuit board via, so as to carry out batch stable and high-precision control of the backdrilling residual piles of the thick and multi-layer circuit boards.

[0098] Figure 5 The back drilling processing device for a circuit board via hole provided by an embodiment of the present invention is a schematic diagram of the structure. The back drilling processing device can be applied to the application scenario where a circuit board needs to back drill a via hole. The back drilling processing device can be implemented in the form of software and / or hardware, and the back drilling processing device can be configured in a control board. Figure 5 As shown, the back drilling processing device includes:

[0099] A single-drill drilling module 41 is used to determine the positioning holes of the circuit board and perform single-drill drilling on the positioning holes to obtain via slices; a scaling ratio determination module 42 is used to determine the thickness scaling ratio of the circuit board in the actual production process according to the via slices; a drill belt generation module 43 is used to output the back-drilling belt of each positioning hole according to the thickness scaling ratio; a back-drilling module 44 is used to perform back-drilling positioning according to the back-drilling belt and use each positioning hole to process the back-drilled holes.

[0100] The technical solution in the embodiment of the present invention first determines the positioning holes of the circuit board, and performs a drilling process on the positioning holes to obtain via slices; then, according to the via slices, determines the thickness scaling ratio in the actual production process of the circuit board; then, according to the thickness scaling ratio, outputs the back drill tape of each positioning hole; finally, according to the back drill tape, back drill positioning is performed using each positioning hole to process the back drill hole. Using the above method, the variation law of the thickness of each layer of the laminated circuit board medium can be explored, and a high-precision back drill residual pile control method for thick and multi-layer circuit boards is provided, which reduces the use of the mapping function of the back drill machine, improves the utilization rate of the back drill machine, improves the production efficiency of the back drill processing of the circuit board via, and reduces the production cost, realizes the batch stable control of high-precision back drill residual piles, and speeds up the production cycle.

[0101] Optionally, the scaling ratio determination module 42 includes: a thickness acquisition unit, used to obtain the measured thickness and design thickness of at least part of the stacking structure in the via slice; a scaling ratio calculation unit, used to determine the thickness scaling ratio in the actual production process of the circuit board based on the ratio of the measured thickness and design thickness of at least part of the stacking structure in the via slice.

[0102] Optionally, the circuit board includes at least one stacked copper conductor layer, at least one semi-cured film layer and at least one core board layer; the thickness acquisition unit includes a thickness acquisition sub-unit, and the thickness acquisition sub-unit is used to obtain a first measured thickness and a first designed thickness of the via slice, wherein the first measured thickness is the sum of the thickness of all copper conductor layers between the back side and the target reference layer in the via slice, the thickness of all semi-cured film layers and the thickness of all core board layers, and the first designed thickness is the sum of the designed thickness of all copper conductor layers between the back side and the target reference layer in the via slice, the designed thickness of all semi-cured film layers and the designed thickness of all core board layers; wherein the target reference layer is a core board layer or a semi-cured film layer; the scaling ratio calculation unit includes a scaling ratio calculation sub-unit, and the scaling ratio calculation sub-unit is used to calculate the ratio of the first measured thickness to the first designed thickness as the thickness scaling ratio in the actual production process of the circuit board.

[0103] Optionally, the drill belt generation module 43 may specifically include a design thickness acquisition unit and a back-drill depth calculation unit. The design thickness acquisition unit is used to design the thickness acquisition unit, and the back-drill depth calculation unit is used to calculate the product of the thickness scaling ratio and the design thickness of the target reference layer, obtain the back-drill depth of each positioning hole, and form a back-drill drill belt.

[0104] Optionally, the thickness acquisition subunit can also be used to measure the thickness of the copper conductor layer multiple times and take the average value to obtain the average thickness of the copper conductor layer; measure the thickness of the prepreg layer multiple times and take the average value to obtain the average thickness of the prepreg layer; measure the thickness of the core layer multiple times and take the average value to obtain the average thickness of the core layer; calculate the sum of the average thickness of all copper conductor layers between the back side and the target reference layer in the via slice, the average thickness of all prepreg layers, and the average thickness of all core layers as the first measured thickness of the via slice. The thickness acquisition subunit can also be used to obtain the design thickness of the copper conductor layer, the design thickness of the prepreg layer, and the design thickness of the core layer; calculate the sum of the design thickness of all copper conductor layers between the back side and the target reference layer in the via slice, the design thickness of all prepreg layers, and the design thickness of all core layers as the first design thickness of the via slice.

[0105] The back drilling processing device for a circuit board via provided in an embodiment of the present invention can execute the back drilling processing method for a circuit board via provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0106] Based on the same inventive concept, an embodiment of the present invention further provides a circuit board. Figure 6 is a schematic diagram of the structure of a circuit board provided by an embodiment of the present invention, such as Figure 6 As shown, the circuit board 10 is prepared using the back drilling processing method for circuit board vias as described in any one of the embodiments of the present invention. Therefore, the circuit board 10 provided by the embodiment of the present invention has the corresponding beneficial effects of the back drilling processing method for circuit board vias provided by the embodiment of the present invention, which will not be repeated here.

[0107] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A back drilling method for a circuit board via hole, characterized in that: include: Determine the positioning holes of the circuit board, and perform a drilling process on the positioning holes to obtain via slices; Determining a thickness scaling ratio in an actual production process of the circuit board according to the via slices; outputting the back-drilling drill belt of each of the positioning holes according to the thickness scaling ratio; According to the back-drilling drill belt, back-drilling positioning is performed using each of the positioning holes to machine back-drilled holes; Wherein, determining the thickness scaling ratio of the circuit board in the actual production process according to the via slicing includes: Obtaining a measured thickness and a designed thickness of at least a portion of the stacked structure in the via slice; Determining a thickness scaling ratio in an actual production process of the circuit board according to a ratio of a measured thickness of at least a portion of the stacked structure in the via slice to a designed thickness; Wherein, the circuit board comprises at least one copper conductor layer, at least one prepreg layer and at least one core board layer stacked; Obtaining a measured thickness and a designed thickness of at least a portion of the stacked structure in the via slice, comprising: Obtaining a first measured thickness and a first designed thickness of the via slice, wherein the first measured thickness is the sum of the thickness of all copper conductor layers, the thickness of all prepreg layers, and the thickness of all core layers between the back side of the via slice and the target reference layer, and the first designed thickness is the sum of the designed thickness of all copper conductor layers, the designed thickness of all prepreg layers, and the designed thickness of all core layers between the back side of the via slice and the target reference layer; wherein the target reference layer is a core layer or a prepreg layer; Determining a thickness scaling ratio in an actual production process of the circuit board according to a ratio of a measured thickness of at least a portion of the stacked structure in the via slice to a designed thickness includes: A ratio of the first measured thickness to the first designed thickness is calculated as a thickness scaling ratio in an actual production process of the circuit board.

2. The back drilling method of a circuit board via hole according to claim 1, characterized in that: Outputting the back drilling tape of each positioning hole according to the thickness scaling ratio includes: Obtaining the designed thickness of the target reference layer; The product of the thickness scaling ratio and the design thickness of the target reference layer is calculated to obtain the backdrilling depth of each of the positioning holes, and to form the backdrilling drill belt.

3. The back drilling method of a circuit board via hole according to claim 1, characterized in that: Obtaining a first measured thickness of the via slice, comprising: Measuring the thickness of the copper conductor layer multiple times and taking an average value to obtain an average thickness of the copper conductor layer; Measuring the thickness of the prepreg layer multiple times and taking an average value to obtain an average thickness of the prepreg layer; Measuring the thickness of the core plate layer multiple times and taking an average value to obtain an average thickness of the core plate layer; The sum of the average thickness of all the copper conductor layers between the back side and the target reference layer in the via slice, the average thickness of all the prepreg layers, and the average thickness of all the core board layers is calculated as the first measured thickness of the via slice.

4. The back drilling method for a circuit board via hole according to claim 1, characterized in that: Obtaining a first design thickness of the via slice includes: Obtaining the designed thickness of the copper conductor layer, the designed thickness of the prepreg layer and the designed thickness of the core board layer; The sum of the design thickness of all the copper conductor layers between the back side and the target reference layer in the via slice, the design thickness of all the prepreg layers, and the design thickness of all the core board layers is calculated as the first design thickness of the via slice.

5. A back drilling processing device for a circuit board via hole, characterized in that: include: A drilling module is used to determine the positioning holes of the circuit board and perform a drilling process on the positioning holes to obtain via slices; A scaling ratio determination module, used to determine the thickness scaling ratio of the circuit board in the actual production process according to the via slices; A drill belt generation module, used for outputting a back drill belt of each positioning hole according to the thickness scaling ratio; A back drilling module, used for performing back drilling positioning according to the back drilling belt and utilizing each of the positioning holes to machine back drilling holes; Wherein, the scaling ratio determination module comprises: A thickness acquisition unit, used to acquire a measured thickness and a designed thickness of at least a portion of the stacked structure in the via slice; A scaling ratio calculation unit, used to determine the thickness scaling ratio in the actual production process of the circuit board according to the ratio of the measured thickness of at least part of the stacked structure in the via slice to the designed thickness; Wherein, the circuit board comprises at least one copper conductor layer, at least one prepreg layer and at least one core board layer stacked; The thickness acquisition unit includes a thickness acquisition subunit, and the thickness acquisition subunit is used to acquire a first measured thickness and a first designed thickness of the via slice, wherein the first measured thickness is the sum of the thickness of all copper conductor layers, the thickness of all prepreg layers, and the thickness of all core layers between the back side of the via slice and the target reference layer, and the first designed thickness is the sum of the designed thickness of all copper conductor layers, the designed thickness of all prepreg layers, and the designed thickness of all core layers between the back side of the via slice and the target reference layer; wherein the target reference layer is a core layer or a prepreg layer; The scaling ratio calculation unit includes a scaling ratio calculation subunit, and the scaling ratio calculation subunit is used to calculate the ratio of the first measured thickness to the first designed thickness as the thickness scaling ratio in the actual production process of the circuit board.

6. A circuit board, characterized in that: The circuit board via is prepared using the back drilling method of any one of claims 1 to 4.

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