Disclosure of Invention
The invention aims to provide a buried hole manufacturing method and a PCB (printed circuit board) so as to solve the problems of complicated flow, long period and high cost in the traditional buried hole manufacturing process.
To achieve the purpose, the invention adopts the following technical scheme:
The utility model provides a hole plugging structure for pack into the through-hole of pseudo-metallization, the pore wall of through-hole divides into along its axial in proper order: an upper pore wall to be non-metallized, a middle pore wall to be metallized, and a lower pore wall to be non-metallized; the plug hole structure comprises an inner pipe and an outer pipe;
the inner tube is of a hollow structure and is divided into an upper inner tube body, a middle inner tube body and a lower inner tube body in sequence along the axial direction of the inner tube;
the length of the upper section inner pipe body is not smaller than the length of the upper hole wall, the length of the middle section inner pipe body is equal to the length of the middle hole wall, and the length of the lower section inner pipe body is not smaller than the length of the lower hole wall;
The outer side walls of the upper section inner pipe body and the lower section inner pipe body are respectively sleeved with the outer pipe, and the outer pipe is used for being attached to the upper hole wall and the lower hole wall so as to prevent copper deposition or electroplating liquid medicine from contacting the upper hole wall and the lower hole wall;
The tube wall of the middle section inner tube body is provided with a hollow structure for circulating the copper deposition or electroplating liquid medicine.
Optionally, the inner tube is made of hard plastic material, and the outer tube is made of flexible rubber material.
Optionally, the thickness of the outer tube is greater than the thickness of the inner tube.
Optionally, designated areas of the inner tube and the outer tube are coated with a nonpolar material, and the designated areas are non-contact surfaces of the hole plugging structure, which are in non-contact with the hole wall of the through hole in a state of being plugged into the through hole.
A buried hole manufacturing method comprises the following steps:
Drilling through holes on the printed circuit board, wherein the through holes are sequentially divided into: an upper pore wall to be non-metallized, a middle pore wall to be metallized, and a lower pore wall to be non-metallized;
the plug hole structure is plugged into the through hole until the middle inner pipe body of the plug hole structure is aligned with the middle hole wall of the through hole;
Carrying out copper deposition electroplating on the through hole plugged into the hole plugging structure so as to form an electroplated layer on the middle hole wall of the through hole;
And removing the hole plugging structure, and plugging the through hole with resin to obtain a buried hole.
Optionally, the length of the upper inner pipe body is equal to the length of the upper hole wall, and the length of the lower inner pipe body is equal to the length of the lower hole wall;
the method for plugging the plug hole structure into the through hole comprises the following steps: and taking the orifice at any end of the through hole as an inlet end, and plugging the plug hole structure into the through hole until the two axial ends of the inner tube are leveled with the two axial ends of the through hole.
Optionally, the length of the upper section inner pipe body of the inner pipe is greater than the length of the upper hole wall, and the outer end of the upper section inner pipe body is provided with a hole plugging depth mark; and/or the length of the lower section inner pipe body of the inner pipe is greater than the length of the lower hole wall, and the outer end of the lower section inner pipe body is provided with a hole plugging depth mark;
the method for plugging the plug hole structure into the through hole comprises the following steps: and plugging the plug hole structure into a preset depth position according to the plug hole depth mark. And cutting off the exposed part of the plug hole structure outside the through hole after the copper deposition electroplating is completed.
Optionally, the method further comprises: and after the copper deposition electroplating is completed, pushing the plug hole structure out of the through hole by using a push rod.
A PCB comprising a buried via, the buried via being made according to any one of the buried via making methods described above.
Compared with the prior art, the invention has the beneficial effects that:
According to the embodiment of the invention, a hole plugging structure capable of carrying out plating resistance on two end areas and not plating resistance on an intermediate area is designed aiming at a buried hole, after a through hole is drilled, the hole plugging structure is plugged into the through hole, copper deposition electroplating is carried out on the through hole, and a resin hole plugging is carried out, so that a blind hole structure with the intermediate metallization and the non-metallization at two ends can be obtained. Compared with the prior art, the process simplifies the secondary lamination operation into the primary lamination operation, greatly simplifies the flow, shortens the manufacturing period and reduces the processing cost.
Detailed Description
In order to make the objects, features and advantages of the present invention more comprehensible, the technical solutions in the embodiments of the present invention are described in detail below with reference to the accompanying drawings, and it is apparent that the embodiments described below are only some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In order to solve various problems of complicated flow, long period, high cost and the like of the conventional secondary press-fit finding mode, the embodiment of the invention provides a brand-new solving idea, a novel plug hole structure 1 with a partial plating blocking function is plugged into a through hole 3, and then conventional copper deposition electroplating is carried out on the through hole 3, so that an electroplated layer can be plated on the middle hole wall of the through hole 3, and no electroplated layer is plated on the hole walls at two ends to form a buried hole.
For convenience of description, for the through-hole 3 for making the buried hole, the hole wall of the through-hole 3 is divided into: an upper pore wall that is to be non-metallized, a middle pore wall that is to be metallized, and a lower pore wall that is to be non-metallized.
Referring to fig. 1, an embodiment of the present invention provides a plug hole structure 1 for plugging a through hole 3 to be partially metallized, wherein the plug hole structure 1 includes an inner tube 11 and an outer tube 12;
the inner tube 11 is of a hollow structure and is divided into an upper inner tube body, a middle inner tube body and a lower inner tube body in sequence along the axial direction of the inner tube; the length of the inner pipe body in the middle section is equal to the length of the middle hole wall of the through hole 3 to be metallized;
The outer tube 12 is fixedly sleeved on the periphery of the upper inner tube body and the periphery of the lower inner tube body of the inner tube 11, and the outer side wall of the outer tube 12 is attached to the upper hole wall and the lower hole wall of the through hole 3 so as to prevent copper deposition or electroplating liquid from contacting the upper hole wall and the lower hole wall of the through hole 3 and prevent the upper hole wall and the lower hole wall of the through hole 3 from forming an electroplated layer.
Meanwhile, the hollow structure 13 for copper deposition or electroplating liquid circulation is arranged on the pipe wall of the middle inner pipe body, and the hollow structure 13 can realize copper deposition or electroplating liquid exchange in the middle hole wall area of the through hole 3 so as to ensure that the middle hole wall of the through hole 3 can be plated with an electroplated layer successfully.
It can be understood that when the outer tube 12 of the plug hole structure 1 is plugged into the through hole 3, the outer side wall of the outer tube 12 can keep a fit state with the upper hole wall and the lower hole wall of the through hole 3, so that when the through hole 3 is completely immersed in the copper deposition or electroplating solution, the outer tube 12 can block the copper deposition or electroplating solution so as to prevent the copper deposition or electroplating solution from contacting with the upper hole wall and the lower hole wall of the through hole 3; meanwhile, the outer tube 12 is not coated on the outer periphery of the middle inner tube of the inner tube 11, and the hollow structure is arranged on the tube wall of the middle inner tube, so that copper deposition or electroplating chemical water can pass through the hollow structure and contact with the middle hole wall of the through hole 3 to form an electroplated layer on the surface of the inner tube. Thus, by using the plug hole structure 1, buried holes can be formed.
For the plating resist effect, the outer tube 12 may be made of any material such as non-conductive plastic, so long as it cannot penetrate the copper deposition or plating solution to cause the copper deposition or plating solution to contact the inner wall of the through hole 3 at the corresponding position.
In an alternative embodiment, the inner tube 11 is a rigid plastic, referred to as a stiffer plastic. Because the inner tube 11 is hard plastic, the hard plastic has good supporting performance due to the large hardness, and the whole length of the hole plugging structure 1 can be kept in a stable state in the hole plugging process, so that the hole plugging structure 1 can be plugged into the preset depth position of the through hole 3 quickly, and the hole plugging precision is improved. Illustratively, the rigid plastic is PC (polycarbonate) material or AS (styrene-acrylonitrile copolymer) material.
Meanwhile, in order to improve the fitting degree, the outer tube 12 is made of flexible rubber, and the flexible rubber has good elastic deformation performance, so that adaptive deformation can be generated under the limiting action of the wall of the through hole 3 in the hole plugging process, the current through hole 3 is matched with the outer tube 12 to a larger extent, and the fitting degree of the wall of the through hole 3 is improved. In this way, not only the manufacturing tolerance existing between the aperture of the through hole 3 and the outer diameter of the hole plugging structure 1 can be overcome, but also the compatibility of the hole plugging structure 1 to a group of through holes 3 (including a plurality of through holes 3 with theoretical aperture manufacturing differences within a preset range) can be realized.
In order to further improve reusability of the plug hole structure 1, designated areas of the inner tube 11 and the outer tube 12, which are non-contact surfaces of the plug hole structure 1 not in contact with the wall of the through hole 3 in a state of being plugged into the through hole 3, are coated with a non-polar material. The nonpolar material can avoid corrosion or electroplating layer formation on the surface of the plug hole structure 1 caused by chemical reaction between the surface of the plug hole structure 1 and the liquid medicine when immersed in copper deposition or electroplating liquid medicine.
Referring to fig. 2 and 3, the embodiment of the invention further provides a buried hole manufacturing method, which includes the steps of:
Step 101, drilling a through hole 3 on the printed circuit board 2.
Specifically, the printed circuit board 2 can be obtained by laminating and laminating according to the conventional procedure, and then the through hole 3 is drilled on the printed circuit board 2.
Step 102, plugging the hole plugging structure 1 into the through hole 3, so that the middle section inner pipe body of the outer pipe 12 is not covered on the periphery of the inner pipe 11 of the hole plugging structure 1 and the middle hole wall of the through hole 3 are aligned.
In this embodiment, the length of the middle inner tube body of the inner tube 11 is substantially equal to the length of the middle hole wall of the through hole 3, so that the position alignment refers to the whole alignment, so that each position of the middle hole wall of the through hole 3 can be ensured to be plated with an electroplated layer in the subsequent copper deposition electroplating process.
In one possible embodiment, the length of the upper inner tube body of the inner tube 11 is equal to the length of the upper aperture wall of the through-hole 3 to be non-metallized, and the length of the lower inner tube body of the inner tube 11 is equal to the length of the lower aperture wall of the through-hole 3 to be metallized. At this time, the overall length of the hole plugging structure 1 is equal to the overall depth of the through hole 3, and the method for plugging the hole plugging structure 1 into the through hole 3 is as follows: the plug hole structure 1 is completely plugged into the through hole 3 until both ends of the inner tube 11 are leveled with both ends of the through hole 3. The hole plugging method is simple and quick, can realize accurate partial metallization of the through hole 3, and does not have hole plugging depth control difficulty and complexity.
In another possible embodiment, the length of the upper inner pipe body of the inner pipe 11 is greater than the length of the upper aperture wall to be non-metallized of the through-hole 3, and the length of the lower inner pipe body of the inner pipe 11 is equal to the length of the lower aperture wall to be non-metallized of the through-hole 3; or the length of the lower section inner pipe body of the inner pipe 11 is larger than the length of the non-metallic lower hole wall of the through hole 3, and the length of the upper section inner pipe body of the inner pipe 11 is equal to the length of the non-metallic upper hole wall of the through hole 3. At this time, after the hole plugging structure 1 is plugged in place, one end of the inner tube 11 is exposed to the outside, and the other end is leveled with the end of the through hole 3. Thus, in this case, the method of plugging the plug hole structure 1 into the through hole 3 may be: the plug hole structure 1 is plugged directly into the through hole 3 until the quasi-flat end of the inner tube 11 and the corresponding end of the through hole 3 reach an actual substantially flat state. The mode is convenient for accurate plugging in and convenient for subsequent taking out.
In a further possible embodiment, the length of the upper inner tube body of the inner tube 11 is greater than the length of the upper portion wall of the through hole 3 to be non-metallized, and the length of the lower inner tube body of the inner tube 11 is greater than the length of the lower portion wall of the through hole 3 to be non-metallized, and the outer ends of the upper inner tube body and/or the lower inner tube body are provided with plug hole depth marks. At this time, both ends of the inner tube 11 are exposed after the hole plugging structure 1 is plugged in place. Thus, in this case, the method of plugging the plug hole structure 1 into the through hole 3 may be: and plugging the plug hole structure 1 into a preset depth position according to the plug hole depth mark. The plug hole structure 1 in this way has a strong versatility. For a group of through holes 3 with the same aperture, if the lengths of the intermediate hole walls to be metallized are equal and the lengths of the upper hole walls to be non-metallized/the lower hole walls to be non-metallized are different, the group of through holes 3 can be used for manufacturing different buried holes by the same hole plugging structure 1, and only the matched hole plugging structure 1 is required to be manufactured according to the through hole 3 with the largest depth.
It should be noted that, the plug hole depth mark may be any mark type capable of being visualized, such as graduations, characters, graphics, symbols, and the like.
Step 103, performing copper deposition electroplating on the through hole 3 plugged into the plug hole structure 1 to form an electroplated layer on the middle hole wall of the through hole 3.
After the through hole structure 1 is plugged, the upper hole wall and the lower hole wall of the through hole 3 are both blocked by the outer tube 12, and only the middle hole wall is not blocked by the outer tube 12, so that the upper hole wall and the lower hole wall of the through hole 3 cannot form an electroplated layer after copper deposition electroplating, and the middle hole wall of the through hole 3 forms an electroplated layer.
It should be noted that, because the entire plug hole structure 1 is a hollow structure, in the copper deposition electroplating process, copper deposition or electroplating chemical water can smoothly pass through the middle gap of the plug hole structure 1 to realize good exchange in the middle hole wall area, so as to ensure the thickness uniformity and flatness of the electroplated layer.
And 104, removing the hole plugging structure 1, and plugging the through hole 3 with resin to obtain a buried hole.
In practical application, if the hole plugging structure 1 does not affect the normal use of the subsequent printed circuit board 2, the hole plugging structure 1 in the through hole 3 can be reserved, and no additional removal operation is performed. In the case that the overall length of the plug hole structure 1 is greater than the depth of the through hole 3, the exposed portion of the plug hole structure 1 outside the through hole 3 may be cut off after the copper plating is completed.
Of course, the hole plugging structure 1 may be removed alternatively, and in particular, different removing manners may be adopted according to the specific material of the hole plugging structure 1, which is not limited in this embodiment of the present invention. Two general manners of removing the plug hole structure 1 are provided: when the hole plugging structure 1 is completely positioned in the through hole 3, a push rod can be used for pushing the hole plugging structure 1 out of the through hole 3; when the hole-plugging structure 1 is partially exposed outside the through hole 3, the hole-plugging structure 1 can be directly pulled out of the through hole 3 manually or automatically by a machine.
In summary, according to the PCB manufacturing method provided by the embodiment of the present invention, the buried hole can be manufactured by simply plugging the through hole 3 with the adapted hole plugging structure 1 and then copper plating and resin hole plugging.
The embodiment of the invention also provides a PCB with the buried hole, and the buried hole is manufactured according to the buried hole manufacturing method. The buried hole of the PCB is manufactured by adopting the method, so that the PCB has good product quality.
The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.