A manufacturing method for resin plugging holes in a printed circuit board and a circuit board

Abstract

The present invention relates to a manufacturing method for resin plugging holes of a printed circuit board and a circuit board. The key points of the technical solution are as follows: The method includes: dividing all the back-drilled holes on each back-drilled surface of the circuit board to be processed into dense holes and non-dense holes; equally dividing all the dense holes on each back-drilled surface into two groups that are alternately arranged in sequence to obtain a first dense hole group and a second dense hole group corresponding to each back-drilled surface; plugging the holes of the first dense hole group on the same back-drilled surface, and plugging the holes of the second dense hole group, non-dense holes and through holes on the same back-drilled surface; performing post-curing and grinding on the circuit board to be processed after hole plugging; This application can ensure that there is sufficient ink filling amount in all the back-drilled holes, and solve problems such as incomplete hole plugging and voids in the back-drilled holes.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit board manufacturing, and more specifically, it relates to a method for manufacturing resin plug holes in printed circuit boards and a circuit board. Background Art

[0002] With the development of printed circuit boards towards higher aspect ratios and higher density of back drill pitches, for resin plug holes in back drills with a high aspect ratio where the PCB board thickness ≥ 5 mm, back drill depth ≥ 4.0 mm, and the distance H between back drill holes ≤ 0.8 mm, due to the small hole pitch, large hole density, and a fixed amount of ink under the squeegee during the ink screen printing process, there will be a problem of insufficient ink filling in the back drill holes, which easily leads to incomplete plugging of the holes. If the back drill holes of resin plug holes with a high aspect ratio are plugged twice or more, at this time, defects such as plug hole bubbles and plug hole voids are extremely likely to occur in the back drill holes.

[0003] For the existing method of resin plug holes with a high aspect ratio, reference can be made to the invention patent with the Chinese patent application number CN201110101403.1. It reduces the viscosity of the resin by degassing the resin to ensure that a board with a high aspect ratio can be plugged through with one cut. In the actual application of the above invention patent, for resin plug holes with a high aspect ratio and a close hole pitch, due to the relatively large back drill depth and small hole distance, the more holes there are in the area, the more ink is required. Therefore, each time the holes are plugged, the ink in the back drill holes cannot be evenly distributed, resulting in serious bubbles and fault-like voids during hole plugging, seriously affecting the product quality. Therefore, there is still room for improvement. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a method for manufacturing resin plug holes in printed circuit boards and a circuit board to solve the above technical problems.

[0005] In the first aspect, the present invention provides a method for manufacturing resin plug holes in printed circuit boards and a circuit board, including:

[0006] Dividing all the back drill holes on each back drill surface of the to-be-processed circuit board into dense holes and non-dense holes;

[0007] Dividing all the dense holes on each back drill surface into two groups that are alternately arranged in sequence, obtaining a first dense hole group and a second dense hole group corresponding to each back drill surface;

[0008] Plugging the holes of the first dense hole group on the same back drill surface, and plugging the holes of the second dense hole group, non-dense holes, and through holes on the same back drill surface;

[0009] Performing post-curing and grinding on the to-be-processed circuit board after hole plugging.

[0010] Specifically, first divide all the back-drilled holes on the circuit board to be processed. The back-drilled holes with a distance less than or equal to the first preset distance from any adjacent back-drilled hole are defined as dense holes, and the back-drilled holes with a distance greater than the first preset distance from all adjacent back-drilled holes are defined as non-dense holes. Subsequently, all the dense holes corresponding to each back-drilled surface are evenly divided into two groups arranged alternately in sequence, obtaining the first dense hole group and the second dense hole group corresponding to each back-drilled surface; by dividing the dense holes into two alternately arranged groups, any dense hole and its adjacent dense hole do not belong to the same dense hole group. Subsequently, plug the holes of the two back-drilled surfaces of the circuit board to be processed respectively according to the distribution of the dense holes on the two back-drilled surfaces. For example, if there are dense holes on one back-drilled surface of the circuit board to be processed and no dense holes on the other back-drilled surface, first plug the first dense hole group on the back-drilled surface with dense holes, then plug the second dense hole group, non-dense holes and through holes, and finally plug the non-dense holes and through holes on the other back-drilled surface, and at the same time perform counter-plugging on the holes that have been plugged on one back-drilled surface, then the hole plugging of the circuit board to be processed can be completed. Finally, post-cure the circuit board to be processed after plugging, and resin grind the circuit board to be processed after complete post-curing, then the resin plugging process of the circuit board to be processed can be completed.

[0011] In the present invention, by dividing the back-drilled holes of each back-drilled surface in the circuit board to be processed and dividing the dense holes into two groups that intersect with each other, when plugging the holes of the circuit board to be processed, first plug the first dense hole group, and then plug the second dense hole group, non-dense holes and through holes. By plugging the first dense hole group and the second dense hole group respectively, it can ensure that each dense hole has sufficient ink filling amount, thus solving the problems of insufficient plugging and voids in the high aspect ratio back-drilled holes with small back-drilled hole pitch.

[0012] Optionally, the step of dividing all the back-drilled holes of each back-drilled surface of the circuit board to be processed into dense holes and non-dense holes includes:

[0013] Obtain the distances between all adjacent back-drilled holes in each back-drilled surface of the circuit board to be processed;

[0014] Divide the back-drilled holes of each back-drilled surface according to the distances to obtain the dense holes and non-dense holes corresponding to each back-drilled surface.

[0015] Specifically, determine the distances between all back-drilled holes on the two back-drilled surfaces according to the PCB design information, compare the distance between each back-drilled hole and its adjacent back-drilled hole with the first preset distance, define the back-drilled holes with a distance less than or equal to the first preset distance from any adjacent back-drilled hole as dense holes, and define the back-drilled holes with a distance greater than the first preset distance from all adjacent back-drilled holes as non-dense holes. Among them, the first preset distance is set by the operator according to the actual situation.

[0016] Optionally, dividing all the dense holes of each back-drilled surface into two groups that are alternately arranged in sequence to obtain a first dense hole group and a second dense hole group corresponding to each back-drilled surface includes:

[0017] Taking one dense hole adjacent to a through hole, a non-dense hole or the circuit board boundary in each back-drilled surface as a starting hole, regularly and alternately selecting non-adjacent dense holes to form a first dense hole group, and taking the remaining dense holes as a second dense hole group.

[0018] Specifically, taking one dense hole adjacent to a through hole, a non-dense hole or the boundary of the to-be-processed circuit board in any back-drilled surface as a starting hole, regularly and alternately selecting non-adjacent dense holes to form an alternately arranged first dense hole group, and then taking the remaining dense holes as a second dense hole group, so that the adjacent dense holes of each dense hole in the first dense hole group and the second dense hole group are in the other dense hole group.

[0019] Optionally, plugging the holes of the first dense hole group of the same back-drilled surface and plugging the holes of the second dense hole group, non-dense holes and through holes of the same back-drilled surface includes:

[0020] Plugging the holes of the first dense hole group of a back-drilled surface and plugging the holes of the second dense hole group, non-dense holes and through holes of the same back-drilled surface;

[0021] Plugging the holes of the first dense hole group of another back-drilled surface and plugging the holes of the second dense hole group, non-dense holes and through holes of the same back-drilled surface.

[0022] Specifically, when performing resin hole plugging on the to-be-processed circuit board, first allocate according to the situation of the dense holes in the two back-drilled surfaces of the to-be-processed circuit board. If there are dense holes in both back-drilled surfaces of the to-be-processed circuit board, start hole plugging from any back-drilled surface. First, plug the holes of the first dense hole group of this back-drilled surface, and then plug the holes of the second dense hole group, non-dense holes and through holes of this back-drilled surface to ensure that there is sufficient ink feeding amount in all the dense holes of the first dense hole group and the second dense hole group. Subsequently, perform hole plugging on the other back-drilled surface. After plugging the holes of the first dense hole group in the other back-drilled surface, then plug the holes of the second dense hole group, non-dense holes and through holes of this back-drilled surface, and perform counter plugging on all the back-drilled holes with plugged holes of one back-drilled surface, then the hole plugging of the to-be-processed circuit board can be completed. If there is only one back-drilled surface with dense holes in the to-be-processed circuit board, first plug the holes of the first dense hole group of the back-drilled surface with dense holes, then plug the holes of the second dense hole group, non-dense holes and through holes of this back-drilled surface, and finally plug the non-dense holes and through holes of the back-drilled surface without dense holes, and perform counter plugging on the back-drilled holes corresponding to the back-drilled surface with dense holes, then the hole plugging of the to-be-processed circuit board can be completed.

[0023] Optionally, plugging the first dense hole group of a backdrilled surface and plugging the second dense hole group, non-dense holes, and through holes of the same backdrilled surface includes:

[0024] Pre-manufacture a first aluminum sheet and a second aluminum sheet that are correspondingly adapted to a backdrilled surface; a first lower oil hole corresponding to the first dense hole group of a backdrilled surface is provided on the first aluminum sheet; a second lower oil hole corresponding to the second dense hole group, non-dense holes, and through holes of the same backdrilled surface is provided on the second aluminum sheet;

[0025] Place the first aluminum sheet and the second aluminum sheet on a backdrilled surface in sequence, and plug the first dense hole group, second dense hole group, non-dense holes, and through holes of the backdrilled surface respectively.

[0026] Specifically, before plugging the dense holes on a backdrilled surface, a corresponding first aluminum sheet needs to be manufactured according to the position of the first dense hole group of the backdrilled surface, and a first lower oil hole corresponding to the first dense hole group is provided on the first aluminum sheet. A corresponding second aluminum sheet is manufactured according to the positions of the second dense hole group, non-dense holes, and through holes of the backdrilled surface, and a second lower oil hole corresponding to the second dense hole group, non-dense holes, and through holes is provided on the second aluminum sheet. When resin plugging the backdrilled surface, first place the first aluminum sheet on the backdrilled surface, and let oil through the first lower oil hole on the first aluminum sheet to only plug the first dense hole group. Subsequently, place the second aluminum sheet on the backdrilled surface, and let oil through the second lower oil hole on the second aluminum sheet to plug the second dense hole group, non-dense holes, and through holes. Since there is no lower oil hole corresponding to the first dense hole group on the second aluminum sheet, the ink in the first dense hole group will not be affected when letting oil for the second dense hole group, avoiding bubbles or fault-like voids caused by plugging the first dense hole group multiple times.

[0027] Optionally, the placing the first aluminum sheet and the second aluminum sheet on a backdrilled surface in sequence and plugging the first dense hole group, second dense hole group, non-dense holes, and through holes of a backdrill respectively includes:

[0028] Place the first aluminum sheet on the corresponding backdrilled surface, and let oil through the first lower oil hole on the first aluminum sheet to plug the first dense hole group on the backdrilled surface;

[0029] Place the second aluminum sheet on the same backdrilled surface, and let oil through the second lower oil hole on the second aluminum sheet to plug the second dense hole group, non-dense holes, and through holes of the backdrilled surface.

[0030] Specifically, when performing resin plugging on the back-drilled surface, first place the first aluminum sheet on the back-drilled surface and apply oil through the first oil-down hole on the first aluminum sheet to achieve plugging only the first dense hole group. Subsequently, place the second aluminum sheet on the back-drilled surface and apply oil through the second oil-down hole on the second aluminum sheet to achieve plugging the second dense hole group, non-dense holes, and through holes. Since there is no oil-down hole corresponding to the first dense hole group on the second aluminum sheet, the ink in the first dense hole component will not be affected when applying oil to the second dense hole group, avoiding bubbles or fault-like voids caused by multiple plugging of the first dense hole group.

[0031] Optionally, plugging the first dense hole group on another back-drilled surface and plugging the second dense hole group, non-dense holes, and through holes on the same back-drilled surface includes:

[0032] Pre-manufacture a third aluminum sheet and a fourth aluminum sheet corresponding and adapted to another back-drilled surface; the third aluminum sheet is provided with a third oil-down hole corresponding and adapted to the first dense hole group on another back-drilled surface; the fourth aluminum sheet is provided with a fourth oil-down hole corresponding and adapted to the second dense hole group, non-dense holes, through holes, and the plugging holes of the back-drilled holes on one back-drilled surface;

[0033] Place the third aluminum sheet and the fourth aluminum sheet on another back-drilled surface in sequence, and perform plugging on the first dense hole group, second dense hole group, non-dense holes, through holes, and the plugging holes of the back-drilled holes on one back-drilled surface on another back-drilled surface respectively.

[0034] When there are dense holes on both back-drilled surfaces of the circuit board to be processed, aluminum sheets need to be manufactured according to both back-drilled surfaces of the circuit board to be processed. Specifically, before plugging the dense holes on another back-drilled surface, a corresponding third aluminum sheet needs to be manufactured according to the position of the first dense hole group on this back-drilled surface, and the third aluminum sheet is provided with a third oil-down hole corresponding to the first dense hole group. A corresponding fourth aluminum sheet is manufactured according to the positions of the second dense hole group, non-dense holes, through holes, and the plugging holes of the back-drilled holes on one back-drilled surface on this back-drilled surface, and a fourth oil-down hole corresponding to the second dense hole group, non-dense holes, through holes, and the back-drilled holes on one back-drilled surface is provided on the fourth aluminum sheet. When performing resin plugging on this back-drilled surface, first place the third aluminum sheet on this back-drilled surface and apply oil through the third oil-down hole on the third aluminum sheet to achieve plugging only the first dense hole group on this back-drilled surface. Subsequently, place the fourth aluminum sheet on this back-drilled surface and apply oil through the fourth oil-down hole on the fourth aluminum sheet to achieve plugging the second dense hole group, non-dense holes, through holes, and the back-drilled holes on one back-drilled surface. Since there is no oil-down hole corresponding to the first dense hole group on the fourth aluminum sheet, the ink in the first dense hole component will not be affected when applying oil to the second dense hole group, avoiding bubbles or fault-like voids caused by multiple plugging of the first dense hole group.

[0035] Optionally, placing the third aluminum sheet and the fourth aluminum sheet on another back-drilled surface in sequence, and plugging the first dense hole group, the second dense hole group, the non-dense holes, the through holes, and the counterbore holes of the back-drilled holes on one back-drilled surface respectively, includes:

[0036] Place the third aluminum sheet on the corresponding back-drilled surface, inject oil through the third lower oil hole on the third aluminum sheet, and plug the first dense hole group of this back-drilling;

[0037] Place the fourth aluminum sheet on the same back-drilled surface, inject oil through the fourth lower oil hole on the fourth aluminum sheet, and plug the second dense hole group, the non-dense holes, the through holes, and the counterbore holes of the back-drilled holes on this back-drilled surface.

[0038] Specifically, when resin plugging is performed on this back-drilled surface, first place the third aluminum sheet on this back-drilled surface, and inject oil through the third lower oil hole on the third aluminum sheet to achieve plugging only the first dense hole group of this back-drilled surface. Subsequently, place the fourth aluminum sheet on this back-drilled surface, and inject oil through the fourth lower oil hole on the fourth aluminum sheet to achieve plugging the second dense hole group, the non-dense holes, the through holes, and the back-drilled holes on one back-drilled surface. Since there is no lower oil hole on the fourth aluminum sheet corresponding to the first dense hole group of this back-drilled surface, the ink in the first dense hole group will not be affected when injecting oil into the second dense hole group, avoiding bubbles or fault-like voids caused by plugging the first dense hole group multiple times.

[0039] Optionally, plugging the first dense hole group on another back-drilled surface and plugging the second dense hole group, the non-dense holes, and the through holes on the same back-drilled surface further includes:

[0040] A depth control backing plate for isolating the vacuum pumping area and the dense holes is provided on one back-drilled surface; grooves corresponding to the positions of the dense holes on one back-drilled surface are opened on the depth control backing plate; through grooves corresponding to the positions of the non-dense holes and the through holes on one back-drilled surface are opened on the depth control backing plate.

[0041] Specifically, after completing the plugging of the first and second dense hole groups on one back-drilled surface, when plugging the first and second dense hole groups, non-dense holes, and back-drilled holes on the other back-drilled surface, in order to prevent the dense holes on the one back-drilled surface from being connected to the vacuum, the dense hole positions on the one back-drilled surface on the depth control pad are not drilled through. Therefore, grooves corresponding to the dense hole positions on the one back-drilled surface are provided on the depth control pad. This can make way for the dense hole positions on the one back-drilled surface and prevent the depth control pad from contacting the resin ink at the dense hole positions on the one back-drilled surface. The non-dense holes and through-hole positions on the depth control pad corresponding to the one back-drilled surface are drilled through. When plugging the non-dense holes and through-holes on the one back-drilled surface, vacuum plugging can be performed to ensure the plugging effect of the non-dense holes and through-holes. At this time, in the vacuum plugging machine, since the positions of the dense holes are isolated by the controlled depth pad, when plugging the dense holes on the back drilled surface, the positions of the dense holes on the back drilled surface will not be affected by the vacuum, so it is not easy to cause the back drilled surface plugging holes to sink, explode, and other hole problems.

[0042] In a second aspect, the present invention further provides a circuit board, which is manufactured using the above-mentioned method for manufacturing resin plug holes in a printed circuit board.

[0043] Specifically, the circuit board manufactured based on the above-mentioned method for manufacturing resin plug holes in a printed circuit board has sufficient resin ink filled in the back-drilled holes with a small back-drilled hole spacing to avoid serious bubbles and fault-like voids in the back-drilled holes, thereby improving product quality.

[0044] In summary, the present invention has the following beneficial effects:

[0045] By dividing the back-drilled holes on each back-drilled surface of the circuit board to be processed and dividing the dense holes into two interlaced groups, when plugging the circuit board to be processed, the first dense hole group is plugged first, and then the second dense hole group, non-dense holes and through holes are plugged. By plugging the first dense hole group and the second dense hole group respectively, it is possible to ensure that there is sufficient ink filling volume in each dense hole, thereby solving the problems of incomplete plugging and voids in back-drilled holes with high aspect ratio and small back-drilling hole spacing. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a flow chart of the method of the present invention;

[0047] Figure 2 This is a schematic diagram of the plugging process of Example 1 of the present invention;

[0048] Figure 3 It is a schematic diagram of the central control depth pad in Example 2 of the present invention. DETAILED DESCRIPTION

[0049] To make the objectives, features, and advantages of the present invention more apparent and understandable, the following provides a detailed description of the specific implementation manners of the present invention with reference to the accompanying drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0050] In the present invention, unless otherwise clearly specified and defined, terms such as "install", "connect", "couple", "fix", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include one or more of such features.

[0051] The following describes the present invention in detail with reference to the accompanying drawings and embodiments.

[0052] Embodiment 1

[0053] This embodiment provides a method for manufacturing a printed circuit board with resin plug holes, as Figure 1 and Figure 2 shown, including:

[0054] Dividing all the back-drilled holes on each back-drilled surface of the to-be-processed circuit board into dense holes and non-dense holes;

[0055] Dividing all the dense holes on each back-drilled surface into two groups that are alternately arranged in sequence, obtaining a first dense hole group and a second dense hole group corresponding to each back-drilled surface;

[0056] Performing plug hole on the first dense hole group of the same back-drilled surface, and performing plug hole on the second dense hole group, non-dense holes, and through holes of the same back-drilled surface;

[0057] Performing post-curing and grinding on the to-be-processed circuit board after plug hole.

[0058] Specifically, first divide all the back-drilled holes on the circuit board to be processed. The back-drilled holes with a spacing less than or equal to the first preset distance from any adjacent back-drilled hole are defined as dense holes, and the back-drilled holes with a distance greater than the first preset distance from all adjacent back-drilled holes are defined as non-dense holes. Subsequently, all the dense holes corresponding to each back-drilled surface are evenly divided into two groups arranged alternately in sequence, obtaining the first dense hole group and the second dense hole group corresponding to each back-drilled surface. By dividing the dense holes into two alternately arranged groups, any dense hole and its adjacent dense hole do not belong to the same dense hole group. Subsequently, plug the holes of the two back-drilled surfaces of the circuit board to be processed respectively according to the distribution of the dense holes on the two back-drilled surfaces. For example, if there are dense holes on one back-drilled surface of the circuit board to be processed and no dense holes on the other back-drilled surface, first plug the first dense hole group of the back-drilled surface with dense holes, then plug the second dense hole group, non-dense holes and through holes, and finally plug the non-dense holes and through holes of the other back-drilled surface, and at the same time perform counter plugging on the holes that have been plugged on one back-drilled surface, then the hole plugging of the circuit board to be processed can be completed. Finally, perform post-curing on the circuit board to be processed after hole plugging, and perform resin grinding on the circuit board to be processed after complete post-curing, then the resin hole plugging process of the circuit board to be processed can be completed. In this embodiment, the first preset distance is 0.8 mm.

[0059] In the present invention, by dividing the back-drilled holes of each back-drilled surface in the circuit board to be processed and dividing the dense holes into two alternately arranged groups, when plugging the holes of the circuit board to be processed, first plug the first dense hole group, and then plug the second dense hole group, non-dense holes and through holes. By plugging the first dense hole group and the second dense hole group respectively, it can be ensured that each dense hole has sufficient ink filling amount, thus solving the problems of incomplete hole plugging and voids in the high aspect ratio back-drilled holes with small back-drilled hole pitch.

[0060] Optionally, the step of dividing all the back-drilled holes of each back-drilled surface of the circuit board to be processed into dense holes and non-dense holes includes:

[0061] Obtain the spacing between all adjacent back-drilled holes in each back-drilled surface of the circuit board to be processed;

[0062] Divide the back-drilled holes of each back-drilled surface according to the spacing, obtaining the dense holes and non-dense holes corresponding to each back-drilled surface.

[0063] Specifically, determine the spacing between all back-drilled holes on two back-drilled surfaces according to the PCB design information. Compare the spacing between each back-drilled hole and its adjacent back-drilled holes with a first preset distance. Designate the back-drilled holes with a spacing less than or equal to the first preset distance from any adjacent back-drilled hole as dense holes, and designate the back-drilled holes with a spacing greater than the first preset distance from all adjacent back-drilled holes as non-dense holes. Herein, the first preset distance is set by the operator according to the actual situation. In this embodiment, the first preset distance is 0.8 mm.

[0064] Optionally, the step of dividing all the dense holes on each back-drilled surface into two groups that alternate with each other to obtain a first dense hole group and a second dense hole group corresponding to each back-drilled surface includes:

[0065] Take one dense hole adjacent to a through hole, a non-dense hole or the circuit board boundary on each back-drilled surface as a starting hole, and regularly and alternately select non-adjacent dense holes starting from the starting hole to form a first dense hole group, and take the remaining dense holes as the second dense hole group.

[0066] Specifically, take one dense hole adjacent to a through hole, a non-dense hole or the boundary of the to-be-processed circuit board on any back-drilled surface as a starting hole, regularly and alternately select non-adjacent dense holes to form an alternating first dense hole group, and then take the remaining dense holes as the second dense hole group, so that the adjacent dense holes of each dense hole in the first dense hole group and the second dense hole group are in the other dense hole group.

[0067] Optionally, the step of plugging the holes of the first dense hole group on the same back-drilled surface and plugging the holes of the second dense hole group, non-dense holes and through holes on the same back-drilled surface includes:

[0068] Plug the holes of the first dense hole group on one back-drilled surface, and plug the holes of the second dense hole group, non-dense holes and through holes on the same back-drilled surface;

[0069] Plug the holes of the first dense hole group on the other back-drilled surface, and plug the holes of the second dense hole group, non-dense holes and through holes on the same back-drilled surface.

[0070] Specifically, when performing resin hole plugging on the to-be-processed circuit board, first allocate according to the situation of the dense holes on the two back-drilled surfaces of the to-be-processed circuit board. If there is only one back-drilled surface with dense holes on the to-be-processed circuit board, first plug the holes of the first dense hole group on the back-drilled surface with dense holes, then plug the holes of the second dense hole group, non-dense holes and through holes on this back-drilled surface, and finally plug the non-dense holes and through holes on the back-drilled surface without dense holes, and perform counter plugging on the back-drilled holes corresponding to the back-drilled surface with dense holes, then the hole plugging of the to-be-processed circuit board can be completed.

[0071] Optionally, plugging the first dense hole group of a back-drilled surface and plugging the second dense hole group, non-dense holes, and through-holes of the same back-drilled surface includes:

[0072] Pre-manufacture a first aluminum sheet and a second aluminum sheet that are correspondingly adapted to a back-drilled surface; a first lower oil hole corresponding to the first dense hole group of a back-drilled surface is provided on the first aluminum sheet; a second lower oil hole corresponding to the second dense hole group, non-dense holes, and through-holes of the same back-drilled surface is provided on the second aluminum sheet;

[0073] Place the first aluminum sheet and the second aluminum sheet on a back-drilled surface in sequence, and plug the first dense hole group, second dense hole group, non-dense holes, and through-holes of the back-drilled surface respectively.

[0074] Specifically, before plugging the dense holes on a back-drilled surface, a corresponding first aluminum sheet needs to be manufactured according to the position of the first dense hole group of this back-drilled surface, and a first lower oil hole corresponding to the first dense hole group is provided on the first aluminum sheet. A corresponding second aluminum sheet is manufactured according to the positions of the second dense hole group, non-dense holes, and through-holes of this back-drilled surface, and a second lower oil hole corresponding to the second dense hole group, non-dense holes, and through-holes is provided on the second aluminum sheet. When resin plugging this back-drilled surface, first place the first aluminum sheet on this back-drilled surface, and let oil through the first lower oil hole on the first aluminum sheet to achieve plugging only the first dense hole group. Subsequently, place the second aluminum sheet on this back-drilled surface, and let oil through the second lower oil hole on the second aluminum sheet to achieve plugging the second dense hole group, non-dense holes, and through-holes. Since there is no lower oil hole corresponding to the first dense hole group on the second aluminum sheet, the ink in the first dense hole group will not be affected when letting oil for the second dense hole group, avoiding bubbles or fault-like voids caused by plugging the first dense hole group multiple times.

[0075] Optionally, the placing the first aluminum sheet and the second aluminum sheet on a back-drilled surface in sequence, and plugging the first dense hole group, second dense hole group, non-dense holes, and through-holes of a back-drilled surface respectively includes:

[0076] Place the first aluminum sheet on the corresponding back-drilled surface, and let oil through the first lower oil hole on the first aluminum sheet to plug the first dense hole group on this back-drilled surface;

[0077] Place the second aluminum sheet on the same back-drilled surface, and let oil through the second lower oil hole on the second aluminum sheet to plug the second dense hole group, non-dense holes, and through-holes of this back-drilled surface.

[0078] Specifically, when resin plugging the back-drilled surface, first place the first aluminum sheet on the back-drilled surface and apply oil through the first oil hole on the first aluminum sheet to achieve plugging only the first dense hole group. Subsequently, place the second aluminum sheet on the back-drilled surface and apply oil through the second oil hole on the second aluminum sheet to achieve plugging the second dense hole group, non-dense holes, and through holes. Since there is no oil hole corresponding to the first dense hole group on the second aluminum sheet, the ink in the first dense hole assembly will not be affected when applying oil to the second dense hole group, avoiding bubbles or fault-like voids caused by multiple plugging of the first dense hole group.

[0079] In this embodiment, taking the case where there are dense holes on only one back-drilled surface as an example, when plugging holes in the PCB board, the following processes are sequentially passed through:

[0080] 1) Board baking: Keep the temperature of the PCB board surface at about 45°C during board baking. Take it out of the oven within 10 minutes when plugging holes and complete all the holes to be plugged.

[0081] 2) Plugging hole 1: Plug the first dense hole group through the first aluminum sheet from one back-drilled surface, and do not plug the through holes and non-dense holes.

[0082] 3) Plugging hole 2: Replace the second aluminum sheet and continue to plug the second dense hole group, through holes, and non-dense holes from this back-drilled surface.

[0083] 4) Plugging hole 3: Replace the aluminum sheet corresponding to the through holes and back-drilled holes on the other back-drilled surface and plug all the through holes and all the back-drilled holes that need to be plugged from the other back-drilled surface.

[0084] 5) Post-curing: Post-cure the plugged PCB board.

[0085] 6) Resin grinding: Grind the PCB board after complete post-curing.

[0086] Embodiment 2

[0087] This embodiment provides a method for manufacturing a printed circuit board with resin plugging holes, as Figure 1 and Figure 3 shown, including:

[0088] Divide all the back-drilled holes on each back-drilled surface of the to-be-processed circuit board into dense holes and non-dense holes;

[0089] Divide all the dense holes on each back-drilled surface into two groups that are alternately arranged in sequence, obtaining the corresponding first dense hole group and second dense hole group for each back-drilled surface;

[0090] Plug the first dense hole group on the same back-drilled surface, and plug the second dense hole group, non-dense holes, and through holes on the same back-drilled surface;

[0091] The post-cured and polished the to-be-processed circuit board after plugging the vias.

[0092] Specifically, first divide all the back-drilled holes on the to-be-processed circuit board. The back-drilled holes with the distance between any adjacent back-drilled holes less than or equal to the first preset distance are defined as dense holes, and the back-drilled holes with the distance between all adjacent back-drilled holes greater than the first preset distance are defined as non-dense holes. Subsequently, all the dense holes corresponding to each back-drilled surface are evenly divided into two groups arranged alternately in sequence, obtaining the first dense hole group and the second dense hole group corresponding to each back-drilled surface; by dividing the dense holes into two alternately arranged groups, any dense hole and its adjacent dense hole do not belong to the same dense hole group. Subsequently, plug the vias of the two back-drilled surfaces of the to-be-processed circuit board respectively according to the distribution of the dense holes on the two back-drilled surfaces. For example, if there are dense holes on one back-drilled surface of the to-be-processed circuit board and no dense holes on the other back-drilled surface, first plug the first dense hole group of the back-drilled surface with dense holes, then plug the second dense hole group, non-dense holes and through holes, and finally plug the non-dense holes and through holes of the other back-drilled surface, and at the same time perform counter plugging on the holes that have been plugged on one back-drilled surface, then the via plugging of the to-be-processed circuit board can be completed. Finally, post-cure the to-be-processed circuit board after plugging, and grind the resin of the to-be-processed circuit board after complete post-curing, then the resin via plugging process of the to-be-processed circuit board can be completed. In this embodiment, the first preset distance is 0.8 mm.

[0093] The present invention divides the back-drilled holes of each back-drilled surface in the to-be-processed circuit board, and divides the dense holes into two groups that intersect with each other. When plugging the to-be-processed circuit board, first plug the first dense hole group, and then plug the second dense hole group, non-dense holes and through holes. By plugging the first dense hole group and the second dense hole group respectively, it can ensure that there is sufficient ink flow in each dense hole, thus solving the problems of incomplete plugging and voids in the high aspect ratio back-drilled holes with small back-drilled hole pitch.

[0094] Optionally, the dividing all the back-drilled holes of each back-drilled surface of the to-be-processed circuit board into dense holes and non-dense holes includes:

[0095] Obtain the distance between all adjacent back-drilled holes in each back-drilled surface of the to-be-processed circuit board;

[0096] Divide the back-drilled holes of each back-drilled surface according to the distance, and obtain the dense holes and non-dense holes corresponding to each back-drilled surface.

[0097] Specifically, determine the spacing between all back-drilled holes on two back-drilled surfaces according to the PCB design information. Compare the spacing between each back-drilled hole and its adjacent back-drilled holes with a first preset distance. Designate the back-drilled holes with a spacing less than or equal to the first preset distance from any adjacent back-drilled hole as dense holes, and designate the back-drilled holes with a spacing greater than the first preset distance from all adjacent back-drilled holes as non-dense holes. The first preset distance is set by the operator according to the actual situation. In this embodiment, the first preset distance is 0.8 mm.

[0098] Optionally, the step of dividing all the dense holes on each back-drilled surface into two groups that alternate with each other to obtain a first dense hole group and a second dense hole group corresponding to each back-drilled surface includes:

[0099] Take a dense hole adjacent to a through hole, a non-dense hole or the circuit board boundary on each back-drilled surface as a starting hole, and regularly and alternately select non-adjacent dense holes starting from the starting hole to form a first dense hole group, and take the remaining dense holes as the second dense hole group.

[0100] Specifically, take a dense hole adjacent to a through hole, a non-dense hole or the boundary of the circuit board to be processed on any back-drilled surface as a starting hole, and regularly and alternately select non-adjacent dense holes to form an interlaced first dense hole group, and then take the remaining dense holes as the second dense hole group, so that the adjacent dense holes of each dense hole in the first dense hole group and the second dense hole group are in the other dense hole group.

[0101] Optionally, the step of plugging the holes of the first dense hole group on the same back-drilled surface and plugging the holes of the second dense hole group, non-dense holes and through holes on the same back-drilled surface includes:

[0102] Plug the holes of the first dense hole group on one back-drilled surface, and plug the holes of the second dense hole group, non-dense holes and through holes on the same back-drilled surface;

[0103] Plug the holes of the first dense hole group on the other back-drilled surface, and plug the holes of the second dense hole group, non-dense holes and through holes on the same back-drilled surface.

[0104] Specifically, when performing resin plugging on the circuit board to be processed, first allocate according to the situation of the dense holes in the two back-drilled surfaces of the circuit board to be processed. If there are dense holes in both back-drilled surfaces of the circuit board to be processed, randomly select one back-drilled surface to start plugging. First, plug the first dense hole group of this back-drilled surface, and then plug the second dense hole group, non-dense holes, and through-holes of this back-drilled surface to ensure that there is sufficient ink supply in all the dense holes of the first dense hole group and the second dense hole group. Subsequently, perform plugging on the other back-drilled surface. After plugging the first dense hole group in the other back-drilled surface, then plug the second dense hole group, non-dense holes, and through-holes of this back-drilled surface, and perform counter plugging on all the back-drilled holes that have been plugged on one back-drilled surface, then the plugging of the circuit board to be processed can be completed.

[0105] Optionally, the plugging of the first dense hole group of a back-drilled surface and the plugging of the second dense hole group, non-dense holes, and through-holes of the same back-drilled surface include:

[0106] Pre-manufacture the first aluminum sheet and the second aluminum sheet that are correspondingly adapted to a back-drilled surface; the first aluminum sheet is provided with first oil holes correspondingly adapted to the first dense hole group of a back-drilled surface; the second aluminum sheet is provided with second oil holes correspondingly adapted to the second dense hole group, non-dense holes, and through-holes of the same back-drilled surface;

[0107] Place the first aluminum sheet and the second aluminum sheet on a back-drilled surface in sequence, and perform plugging on the first dense hole group, the second dense hole group, non-dense holes, and through-holes of a back-drilled surface respectively.

[0108] Specifically, before plugging the dense holes on a back-drilled surface, it is necessary to manufacture the corresponding first aluminum sheet according to the position of the first dense hole group of this back-drilled surface, and the first aluminum sheet is provided with first oil holes corresponding to the first dense hole group. Manufacture the corresponding second aluminum sheet according to the positions of the second dense hole group, non-dense holes, and through-holes of this back-drilled surface, and the second aluminum sheet is provided with second oil holes corresponding to the second dense hole group, non-dense holes, and through-holes. When performing resin plugging on this back-drilled surface, first place the first aluminum sheet on this back-drilled surface and let the oil flow through the first oil holes on the first aluminum sheet to achieve plugging only for the first dense hole group. Subsequently, place the second aluminum sheet on this back-drilled surface and let the oil flow through the second oil holes on the second aluminum sheet to achieve plugging for the second dense hole group, non-dense holes, and through-holes. Since the second aluminum sheet does not have oil holes corresponding to the first dense hole group, the ink in the first dense hole group will not be affected when oiling the second dense hole group, avoiding bubbles or fault-like voids caused by plugging the first dense hole group multiple times.

[0109] Optionally, the placing of the first aluminum sheet and the second aluminum sheet on a back-drilled surface in sequence, and the plugging of the first dense hole group, the second dense hole group, non-dense holes, and through-holes of a back-drilled surface respectively include:

[0110] Place the first aluminum sheet on the corresponding back-drilled surface, pour oil through the first oil hole on the first aluminum sheet, and plug the first dense hole group on the back-drilled surface.

[0111] Place the second aluminum sheet on the same back-drilled surface, pour oil through the second oil hole on the second aluminum sheet, and plug the second dense hole group, non-dense holes, and through holes on the back-drilled surface.

[0112] Specifically, when plugging the resin into the back-drilled surface, first place the first aluminum sheet on the back-drilled surface and pour oil through the first oil hole on the first aluminum sheet to only plug the first dense hole group. Subsequently, place the second aluminum sheet on the back-drilled surface and pour oil through the second oil hole on the second aluminum sheet to plug the second dense hole group, non-dense holes, and through holes. Since there is no oil hole corresponding to the first dense hole group on the second aluminum sheet, the ink in the first dense hole group will not be affected when pouring oil for the second dense hole group, avoiding bubbles or fault-like voids caused by plugging the first dense hole group multiple times.

[0113] Optionally, plugging the first dense hole group on another back-drilled surface and plugging the second dense hole group, non-dense holes, and through holes on the same back-drilled surface includes:

[0114] Pre-manufacture the third aluminum sheet and the fourth aluminum sheet that are correspondingly adapted to another back-drilled surface; the third aluminum sheet is provided with a third oil hole correspondingly adapted to the first dense hole group on another back-drilled surface; the fourth aluminum sheet is provided with a fourth oil hole correspondingly adapted to the second dense hole group, non-dense holes, through holes, and the counter plugging holes of the back-drilled holes on one back-drilled surface.

[0115] Place the third aluminum sheet and the fourth aluminum sheet on another back-drilled surface in sequence, and respectively plug the first dense hole group, second dense hole group, non-dense holes, through holes, and the counter plugging holes of the back-drilled holes on one back-drilled surface on another back-drilled surface.

[0116] When there are dense holes on both back-drilled surfaces of the circuit board to be processed, aluminum sheets need to be fabricated according to both back-drilled surfaces of the circuit board to be processed. Specifically, before plugging the dense holes on the other back-drilled surface, a corresponding third aluminum sheet needs to be fabricated according to the position of the first dense hole group on this back-drilled surface. The third aluminum sheet is provided with third oil holes corresponding to the first dense hole group. A corresponding fourth aluminum sheet is fabricated according to the plugging positions of the second dense hole group, non-dense holes, through holes, and back-drilled holes on one back-drilled surface on the fourth aluminum sheet. The fourth aluminum sheet is provided with fourth oil holes corresponding to the second dense hole group, non-dense holes, through holes, and back-drilled holes on one back-drilled surface. When resin plugging is performed on this back-drilled surface, first place the third aluminum sheet on this back-drilled surface and pour oil through the third oil holes on the third aluminum sheet to achieve plugging only the first dense hole group on this back-drilled surface. Subsequently, place the fourth aluminum sheet on this back-drilled surface and pour oil through the fourth oil holes on the fourth aluminum sheet to achieve plugging the second dense hole group, non-dense holes, through holes, and back-drilled holes on one back-drilled surface. Since the fourth aluminum sheet does not have oil holes corresponding to the first dense hole group on this back-drilled surface, the ink in the first dense hole group will not be affected when pouring oil for the second dense hole group, avoiding bubbles or fault-like voids caused by multiple plugging of the first dense hole group.

[0117] Optionally, the steps of sequentially placing the third aluminum sheet and the fourth aluminum sheet on the other back-drilled surface and plugging the first dense hole group, the second dense hole group, non-dense holes, through holes, and the plugging holes of the back-drilled holes on one back-drilled surface on the other back-drilled surface respectively include:

[0118] Place the third aluminum sheet on the corresponding back-drilled surface and pour oil through the third oil holes in the third aluminum sheet to plug the first dense hole group of this back-drilled surface;

[0119] Place the fourth aluminum sheet on the same back-drilled surface and pour oil through the fourth oil holes in the fourth aluminum sheet to plug the second dense hole group, non-dense holes, through holes, and the plugging holes of the back-drilled holes on one back-drilled surface of this back-drilled surface.

[0120] Specifically, when resin plugging is performed on this back-drilled surface, first place the third aluminum sheet on this back-drilled surface and pour oil through the third oil holes on the third aluminum sheet to achieve plugging only the first dense hole group on this back-drilled surface. Subsequently, place the fourth aluminum sheet on this back-drilled surface and pour oil through the fourth oil holes on the fourth aluminum sheet to achieve plugging the second dense hole group, non-dense holes, through holes, and back-drilled holes on one back-drilled surface. Since the fourth aluminum sheet does not have oil holes corresponding to the first dense hole group on this back-drilled surface, the ink in the first dense hole group will not be affected when pouring oil for the second dense hole group, avoiding bubbles or fault-like voids caused by multiple plugging of the first dense hole group.

[0121] Optionally, plugging the first dense hole group on another back-drilled surface and plugging the second dense hole group, non-dense holes and through holes on the same back-drilled surface further includes:

[0122] A depth control pad is provided on a back drill surface for isolating the vacuum area from the dense holes; a groove corresponding to the position of the dense holes on the back drill surface is provided on the depth control pad; and a through groove corresponding to the position of the non-dense holes and through holes on the back drill surface is provided on the depth control pad.

[0123] Specifically, after completing the plugging of the first and second dense hole groups on one back-drilled surface, when plugging the first and second dense hole groups, non-dense holes, and back-drilled holes on the other back-drilled surface, in order to prevent the dense holes on the one back-drilled surface from being connected to the vacuum, the dense hole positions on the one back-drilled surface on the depth control pad are not drilled through. Therefore, grooves corresponding to the dense hole positions on the one back-drilled surface are provided on the depth control pad. This can make way for the dense hole positions on the one back-drilled surface and prevent the depth control pad from contacting the resin ink at the dense hole positions on the one back-drilled surface. The non-dense holes and through-hole positions on the depth control pad corresponding to the one back-drilled surface are drilled through. When plugging the non-dense holes and through-holes on the one back-drilled surface, vacuum plugging can be performed to ensure the plugging effect of the non-dense holes and through-holes. At this time, in the vacuum plugging machine, since the positions of the dense holes are isolated by the controlled depth pad, when plugging the dense holes on the back drilled surface, the positions of the dense holes on the back drilled surface will not be affected by the vacuum, so it is not easy to cause the back drilled surface plugging holes to sink, explode, and other hole problems.

[0124] In this embodiment, dense holes are present on both the front and back back-drilled surfaces. When plugging holes on a PCB board, the following steps are performed in sequence:

[0125] 1) Baking plate: The baking plate keeps the PCB surface temperature at around 45°C. When plugging holes, take it out of the oven and complete all the holes that need to be plugged within 10 minutes.

[0126] 2) Plug hole 1: Plug the first dense hole group through the first aluminum sheet from the back drill surface. The through holes and non-dense holes are not plugged.

[0127] 3) Plug hole 2: Replace the second aluminum sheet and continue to plug the second dense hole group, through holes and non-dense holes from the back drill surface;

[0128] 4) Plug hole 3: Replace the third aluminum sheet and plug the first dense hole group from the other back-drilled surface;

[0129] 5) Plug hole 4: Replace the fourth aluminum sheet and continue plugging the second dense hole group, through holes and non-dense holes from the back drilled surface;

[0130] 6) Post-baking: Post-curing the plugged PCB board;

[0131] 7) Resin grinding: Grind the PCB board after complete post-curing.

[0132] Example 3

[0133] This example provides a circuit board, which is made based on the method for manufacturing resin plug holes of a printed circuit board described in Example 1 or Example 2 above.

[0134] Specifically, for the circuit board made based on the above method for manufacturing resin plug holes of a printed circuit board, sufficient resin ink is filled in the back-drilled holes with a small back-drilling pitch, avoiding serious bubbles and fault-like voids in the back-drilled holes to improve product quality.

[0135] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements should also be regarded as within the protection scope of the present invention.

Claims

1. A method for manufacturing a resin plug hole in a printed circuit board, characterized in that: include: Dividing all back-drilled holes on each back-drilled surface of the circuit board to be processed into dense holes and non-dense holes; Divide all dense holes on each back-drilled surface into two groups that are staggered in sequence, obtaining a first dense hole group and a second dense hole group corresponding to each back-drilled surface; The first dense hole group on the same back-drilled surface is plugged, and the second dense hole group, non-dense holes and through holes on the same back-drilled surface are plugged; the plugging of the first dense hole group on the same back-drilled surface, and the plugging of the second dense hole group, non-dense holes and through holes on the same back-drilled surface include: plugging a first dense hole group on a back-drilled surface, and plugging a second dense hole group, non-dense holes, and through holes on the same back-drilled surface; The first dense hole group of the other back-drilled surface is plugged, and the second dense hole group, non-dense holes and through holes of the same back-drilled surface are plugged; a depth control pad is provided on one back-drilled surface to isolate the vacuum area from the dense holes; grooves corresponding to the positions of the dense holes on the one back-drilled surface are formed on the depth control pad; through slots corresponding to the positions of the non-dense holes and through holes on the one back-drilled surface are formed on the depth control pad; The circuit board to be processed is post-cured and ground after the vias are plugged.

2. The method for manufacturing a resin plug hole for a printed circuit board according to claim 1, characterized in that: The method of dividing all back-drilled holes on each back-drilled surface of the circuit board to be processed into dense holes and non-dense holes includes: Obtaining the spacing between all adjacent back-drilled holes in each back-drilled surface of the circuit board to be processed; The back-drilled holes of each back-drilled surface are divided according to the spacing to obtain dense holes and non-dense holes corresponding to each back-drilled surface.

3. The method for manufacturing a resin plug hole for a printed circuit board according to claim 1, characterized in that: The method of dividing all dense holes of each back-drilled surface into two groups staggered in sequence to obtain a first dense hole group and a second dense hole group corresponding to each back-drilled surface comprises: A dense hole adjacent to a through hole, a non-dense hole or a circuit board boundary in each back-drilled surface is used as a starting hole. Non-adjacent dense holes are regularly and staggeredly selected with the starting hole as the starting point to form a first dense hole group, and the remaining dense holes are used as a second dense hole group.

4. The method for manufacturing a resin plug hole for a printed circuit board according to claim 1, characterized in that: The method of plugging a first dense hole group on a back-drilled surface and plugging a second dense hole group, non-dense holes and through holes on the same back-drilled surface includes: A first aluminum sheet and a second aluminum sheet are prefabricated to correspond to a back-drilled surface; the first aluminum sheet is provided with a first lower oil hole corresponding to a first dense hole group of the back-drilled surface; the second aluminum sheet is provided with a second lower oil hole corresponding to a second dense hole group, non-dense holes, and through holes of the same back-drilled surface; The first aluminum sheet and the second aluminum sheet are sequentially placed on a back-drilled surface, and the first dense hole group, the second dense hole group, the non-dense holes and the through holes on the back-drilled surface are plugged respectively.

5. The method for manufacturing a resin plug hole for a printed circuit board according to claim 4, characterized in that: The method of sequentially placing the first aluminum sheet and the second aluminum sheet on a back-drilled surface and plugging the back-drilled first dense hole group, the second dense hole group, the non-dense holes and the through holes comprises: Placing a first aluminum sheet on the corresponding back-drilled surface, and applying oil through a first oiling hole on the first aluminum sheet to plug the first dense hole group on the back-drilled surface; A second aluminum sheet is placed on the same back-drilled surface, and oil is supplied from the second oil hole on the second aluminum sheet to plug the second dense hole group, non-dense holes and through holes on the back-drilled surface.

6. The method for manufacturing a resin plug hole for a printed circuit board according to claim 1, characterized in that: The plugging of the first dense hole group on another back-drilled surface and the plugging of the second dense hole group, the non-dense holes and the through holes on the same back-drilled surface include: A third aluminum sheet and a fourth aluminum sheet are prefabricated to correspond to the other back-drilled surface; the third aluminum sheet is provided with a third lower oil hole corresponding to the first dense hole group of the other back-drilled surface; the fourth aluminum sheet is provided with a fourth lower oil hole corresponding to the second dense hole group, the non-dense holes, the through holes, and the plug holes for the back-drilled holes of the back-drilled surface; The third aluminum sheet and the fourth aluminum sheet are sequentially placed on the other back-drilled surface, and the first dense hole group, the second dense hole group, the non-dense holes, the through holes, and the back-drilled holes of the other back-drilled surface are plugged respectively.

7. The method for manufacturing a resin plug hole in a printed circuit board according to claim 6, characterized in that: The method sequentially places the third aluminum sheet and the fourth aluminum sheet on the other back-drilled surface, and plugs the first dense hole group, the second dense hole group, the non-dense holes, the through holes, and the back-drilled holes of the other back-drilled surface, including: Place the third aluminum sheet on the corresponding back-drilled surface, and apply oil through the third oil hole of the third aluminum sheet to plug the first dense hole group drilled back; Place the fourth aluminum sheet on the same back-drilled surface, and oil the fourth oil hole of the fourth aluminum sheet to plug the second dense hole group, non-dense holes, through holes and the back-drilled holes of the back-drilled surface.

8. A circuit board, characterized in that: The printed circuit board is manufactured by applying the method for manufacturing resin plug holes of any one of claims 1 to 7.

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