Disclosure of Invention
The invention provides a printed circuit board hole structure and a preparation method thereof, which are used for relieving the problem of overlarge signal loss of the conventional printed circuit board hole structure.
The invention also provides a printed wiring board having at least one hole structure as described above, which helps to reduce signal transmission loss between electronic parts.
The invention provides a printed circuit board hole structure, which comprises a conical hole and a through hole which are communicated with each other, wherein,
the tapered hole is formed by surrounding a first hole wall, the aperture of the tapered hole is gradually decreased from the surface of the printed circuit board to the inside, and the first hole wall is a metalized hole wall;
the through hole is formed by surrounding a second hole wall, and the second hole wall is an insulating hole wall.
Further, the aperture of the through hole is larger than or equal to 0.5mm.
In a second aspect, the present invention provides a method for preparing a pore structure as described above, comprising the steps of:
the method comprises the steps of punching a printed circuit substrate for the first time to obtain a preset through hole and a preset conical hole, then metalizing the hole walls of the preset through hole and the preset conical hole, finally punching the position of the preset through hole for the second time, removing metal on the surface of the hole wall of the preset through hole, and obtaining the hole structure.
Furthermore, the aperture of the preset through hole is D, the aperture of the through hole is D, and the aperture of the through hole is not less than 0.2mm and not more than (D-D) and not more than 0.4mm.
Further, metallizing the hole walls of the preset through hole and the preset taper hole specifically comprises:
and depositing metal on the wall of the preset through hole and the wall of the preset taper hole by adopting electroplating treatment or chemical treatment to form a metal layer.
Further, the thickness of the metal layer is less than 0.1mm.
Further, the metal is copper.
A third aspect of the invention provides a printed wiring board having at least one aperture arrangement as described in any one of the above.
Furthermore, the number of layers of the printed circuit board is more than or equal to 4, and the thickness of the printed circuit board is more than or equal to 0.8mm.
Furthermore, the taper hole is conducted with the inner layer circuit and the outer layer circuit of the printed circuit board, and the through hole is not conducted with the inner layer circuit or the outer layer circuit.
The implementation of the invention has at least the following advantages:
1. the hole structure provided by the invention is beneficial to reducing signal loss by reducing redundant metallization area of the hole, and the tapered hole can be conducted with the inner layer circuit and the outer layer circuit, and the through hole is not conducted with the inner layer circuit or the outer layer circuit, so that a better wiring way of a wiring layer can be realized.
2. The preparation method provided by the invention can be compatible with the existing production process of the printed circuit board, and is flexible.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
A printed circuit board, that is, a PCB board, is a substrate for assembling electronic parts, and is a printed board in which inter-dot connections and printed elements are formed on a general-purpose substrate in a predetermined design, and has a main function of connecting various electronic parts to a predetermined circuit to perform a relay transmission. The more complex the function of the electronic product, the longer the circuit distance, and the larger the number of contact pins, the necessity of using a multilayer printed wiring board has been growing. The multilayer printed wiring board comprises a plurality of wiring layers, an insulating layer is arranged between every two layers, the wiring layers are at least more than three layers, two layers of the wiring layers are arranged on the outer surface, and the rest wiring layers are pressed in an insulating plate.
In order to solve the problems of the conventional through holes, a first aspect of the present invention provides a printed circuit board hole structure, which includes a tapered hole and a through hole that are communicated with each other, wherein,
the tapered hole is formed by enclosing a first hole wall, the hole diameter of the tapered hole is gradually reduced from the surface of the printed circuit board to the inside, and the first hole wall is a metalized hole wall;
the through hole is formed by surrounding a second hole wall, and the second hole wall is an insulating hole wall.
The invention provides a printed circuit board hole structure, fig. 1 is a schematic diagram of the printed circuit board hole structure provided by an embodiment of the invention, as shown in fig. 1, a printed circuit board comprises a plurality of wiring layers 1 and insulating layers 2, an insulating layer 2 is arranged between each two wiring layers 1, wherein the two wiring layers 1 are arranged on the surface of the printed circuit board, the rest wiring layers 1 are arranged in the printed circuit board, a metal layer 3 is arranged on the surface of the two wiring layers 1 on the surface of the printed circuit board, the printed circuit board comprises a hole communicated with the upper surface and the lower surface thereof for mounting electronic parts and wiring, the hole structure provided by the invention comprises a conical hole 4 and a through hole 5 which are communicated with each other, the conical hole 4 is formed by enclosing a first hole wall, the hole diameter of the conical hole is gradually decreased from the upper surface of the printed circuit board to the inner side, namely the section of the conical hole 4 is in an inverted trapezoid shape, the hole wall of the conical hole 4 is provided with the metal layer 3, namely the conical hole 4 is a metallized hole (PTH), the conical hole 4 is used for mounting embedded type electronic parts, namely the electronic parts are inserted into the conical hole and at least partially embedded into the conical hole; the through hole 5 is formed by surrounding a second hole wall, the hole diameter of the through hole is consistent from the inside to the lower surface of the printed circuit board, namely, the section of the through hole 5 is rectangular, and the hole wall of the through hole has no metal layer, namely, the through hole 5 is a non-metallized hole (NPTH). The hole structure provided by the invention is beneficial to reducing the signal loss between electronic parts by reducing the redundant metallization area of the hole, and in addition, because the tapered hole can participate in signal transmission and the through hole does not participate in signal transmission, the tapered hole can be conducted with the inner layer circuit and the outer layer circuit, and the through hole is not conducted with the inner layer circuit or the outer layer circuit, so that a more excellent wiring mode of a wiring layer can be realized.
In one embodiment, the through-holes have a hole diameter of 0.5mm or greater, in combination with the currently conventional hole structures. With continued reference to FIG. 1, the aperture of the through hole is D, D ≧ 0.5mm.
In summary, the hole structure provided by the invention is helpful for reducing signal loss between electronic parts by reducing redundant metallization area of the hole, and in addition, because the tapered hole can participate in signal transmission and the through hole does not participate in signal transmission, the tapered hole can be conducted with the inner layer line and the outer layer line, and the through hole is not conducted with the inner layer line or the outer layer line, so that a better wiring way of a wiring layer can be realized.
In a second aspect, the present invention provides a method for preparing any of the pore structures described above, comprising the steps of:
the method comprises the steps of punching a printed circuit substrate for the first time to obtain a preset through hole and a preset conical hole, then metalizing the hole walls of the preset through hole and the preset conical hole, finally punching the position of the preset through hole for the second time, removing metal on the surface of the hole wall of the preset through hole, and obtaining the hole structure.
In order to prepare the hole structure shown in fig. 1, the hole structure shown in fig. 1 can be obtained by firstly drilling a printed circuit board by using a drill pin for the first time to obtain a preset tapered hole and a preset through hole, then metalizing the preset tapered hole and the preset through hole, finally performing secondary drilling by using the drill pin with the diameter larger than the aperture of the preset through hole, and removing a metal layer on the wall of the preset through hole. The preparation method provided by the invention can be compatible with the existing production process of the printed circuit board, and is flexible.
In one embodiment, the method for preparing the pore structure specifically comprises the following steps:
step 1, preparing a printed circuit substrate:
the printed circuit board comprises a plurality of wiring layers 1, wherein two layers of insulating layers are arranged on the surface of the printed circuit board, and the size and the material of the printed circuit board can be set according to the production requirement.
Step 2, punching the printed circuit substrate for the first time to obtain a preset through hole and a preset taper hole:
the printed circuit substrate is punched for the first time by adopting the conventional punching technology in the field to obtain a preset through hole and a preset taper hole, specifically, the printed circuit substrate can be punched for the first time to obtain the preset through hole, and then the preset through hole is punched for the further time to obtain the taper hole, namely, the step 2 comprises two steps: and 2.1, punching the printed circuit substrate to obtain a preset through hole structure shown in figure 2b, and 2.2, continuously punching on the basis of the preset through hole to obtain a hole structure shown in figure 2c, wherein the conical hole can be obtained by adopting a drill bit, and the depth of the conical hole is controlled by controlling the opening diameter and the angle of the conical hole.
Step 3, metallizing the hole walls of the preset through hole and the preset taper hole:
after the first punching is finished, metallizing the preset through hole and the preset tapered hole by adopting a conventional process to deposit a metal layer on the hole wall of the preset through hole and the preset tapered hole, and specifically, depositing metal on the hole walls of the preset through hole and the preset tapered hole by adopting electroplating treatment or chemical treatment to form the metal layer; meanwhile, by combining the preparation process of the printed circuit board, a layer of metal layer is deposited on the upper surface and the lower surface of the printed circuit board while the preset through hole and the preset tapered hole are metallized, so as to obtain the structure shown in fig. 2d, wherein the materials, the thicknesses and the deposition modes of the metal layers positioned on the preset through hole, the preset tapered hole and the upper surface and the lower surface of the printed circuit board are the same.
Further, the thickness of the metal layer can be set according to the requirements of the printed wiring board, and generally, the thickness of the metal layer is less than 0.1mm.
Further, the metal is copper.
Step 4, punching for the second time at the position of the preset through hole, and removing metal on the surface of the wall of the preset through hole to obtain the hole structure:
after metallization, punching for the second time at the position of the preset through hole, removing the metal layer on the surface of the wall of the preset through hole, and keeping the metal layer on the surface of the wall of the preset tapered hole, specifically, punching for the second time by using a drill point with a diameter larger than the diameter of the preset through hole, so that the metal layer on the surface of the preset through hole is drilled, and the hole structure shown in fig. 2e is obtained.
The drill point diameter that uses when punching the second time only need will predetermine the through-hole pore wall surface the metal level bore fall can, for the convenience of the preparation of pore structure and reduce the influence to the through-hole aperture, the drill point diameter that uses when punching the second time should not be too big, specifically, the aperture of predetermineeing the through-hole is D, the aperture of through-hole is D, and 0.2mm is less than or equal to (D-D) is less than or equal to 0.4mm.
On the basis of the above preparation method, since the preparation process of the printed wiring board further includes acid etching or alkali etching for removing the excess metal on the surface of the printed wiring board, a person skilled in the art can select the timing of the second punching according to the etching mode of the printed wiring board, for example, when the etching mode uses an acid etching process, step 4 further includes acid etching of the printed wiring board before, that is, the preparation of the printed wiring board includes the following steps: carrying out primary punching on a printed circuit substrate to obtain a preset through hole and a preset tapered hole, then metalizing the hole walls of the preset through hole and the preset tapered hole, then carrying out partial acid etching on a metal layer on the surface of the printed circuit board, and finally carrying out secondary punching on the position of the preset through hole to remove the metal on the surface of the hole wall of the preset through hole to obtain the hole structure; when the etching mode uses the alkaline etching process, the alkaline etching process is placed after the second punching step in the step 4, namely the preparation of the printed circuit board comprises the following steps: the method comprises the steps of punching a printed circuit board for the first time to obtain a preset through hole and a preset tapered hole, then metalizing the hole walls of the preset through hole and the preset tapered hole, punching the position of the preset through hole for the second time, removing metal on the surface of the hole wall of the preset through hole to obtain a hole structure, and finally performing partial alkaline etching on the metal layer on the surface of the printed circuit board to obtain the printed circuit board.
In conclusion, the preparation method provided by the invention can be compatible with the existing printed circuit board production process, and is flexible.
A third aspect of the invention provides a printed wiring board having at least one aperture arrangement as provided in the first aspect of the invention.
The present invention provides a printed wiring board having at least one hole structure provided in the first aspect of the present invention, it is understood that the printed wiring board may further include other hole structures, such as through holes, blind holes, etc., which can be configured by those skilled in the art according to actual needs.
The printed circuit board provided by the invention is specifically a multilayer printed circuit board, specifically, the number of layers of the printed circuit board is more than or equal to 4, the thickness of the printed circuit board is more than or equal to 0.8mm, and the printed circuit board is provided with at least one hole structure, so that the signal loss among electronic parts is reduced by reducing the redundant metallization area of the holes; in addition, the tapered hole can participate in signal transmission, the through hole does not participate in signal transmission, the tapered hole can be conducted with the inner layer line and the outer layer line, the through hole is not conducted with the inner layer line or the outer layer line, and a better wiring mode of the wiring layer is achieved.
The following processes for manufacturing the printed wiring board are specifically described in combination with the acid etching or alkali etching processes, respectively:
example 1
The process for manufacturing the printed circuit board provided in this embodiment includes the following steps:
1. designing a wiring layer according to the design requirements of the printed circuit board, and laminating to obtain the printed circuit board substrate, wherein the number of layers is more than 4, and the thickness is more than 0.8 mm;
2. drilling a printed circuit substrate by using a drill needle with the diameter of 0.2mm to obtain a preset through hole with the aperture of 0.2mm, and then continuously drilling on the basis of the preset through hole to obtain a preset conical hole; carrying out other hole structures on the printed circuit substrate according to design requirements;
3. electroplating copper on the upper surface and the lower surface of the printed circuit board, as well as the surfaces of the preset through hole and the preset tapered hole;
4. according to the design requirement of the printed circuit board, performing acid etching on copper layers on the upper surface and the lower surface of the printed circuit board to manufacture an outer circuit;
5. performing secondary punching on the preset through hole position by using a drill point with the diameter of 0.5mm, and drilling off the copper layer on the wall of the preset through hole without damaging the copper layer in the preset conical hole to obtain the hole structure shown in the figure 1, wherein the aperture D of the through hole is 0.5mm;
6. the complete printed wiring board is produced according to the conventional technical means in the field.
Example 2
The process for manufacturing the printed circuit board provided in this embodiment includes the following steps:
1. designing a wiring layer according to the design requirements of the printed circuit board, and laminating to obtain the printed circuit board substrate, wherein the number of layers is more than 4, and the thickness is more than 0.8 mm;
2. drilling a printed circuit substrate by using a drill needle with the diameter of 0.2mm to obtain a preset through hole with the aperture of 0.2mm, and then continuously drilling on the basis of the preset through hole to obtain a preset conical hole; punching other hole structures on the printed circuit substrate according to design requirements;
3. electroplating copper on the upper surface and the lower surface of the printed circuit board, and the surfaces of the preset through hole and the preset tapered hole;
4. performing secondary punching on the position of the preset through hole by using a drill point with the diameter D, and drilling off the copper layer on the wall of the preset through hole without damaging the copper layer on the wall of the preset conical hole to obtain the hole structure shown in the figure 1, wherein the aperture D of the through hole is 0.5mm;
5. and according to the design requirement of the printed circuit board, alkaline etching is carried out on the copper layers on the upper surface and the lower surface of the printed circuit board, an outer layer circuit is manufactured, and the complete printed circuit board is obtained through production.
In conclusion, the hole structure provided by the invention is beneficial to reducing the signal loss among electronic parts by reducing the redundant metallization area of the hole; in addition, the tapered hole can participate in signal transmission, the through hole does not participate in signal transmission, the tapered hole can be conducted with the inner layer line and the outer layer line, the through hole is not conducted with the inner layer line or the outer layer line, and a better wiring mode of the wiring layer is achieved.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.