CN-122028312-A - Printed circuit board back drilling manufacturing method and printed circuit board

CN122028312ACN 122028312 ACN122028312 ACN 122028312ACN-122028312-A

Abstract

The invention provides a back drilling hole manufacturing method of a printed circuit board and the printed circuit board, the back drilling hole manufacturing method of the printed circuit board comprises the steps of providing the circuit board, obtaining a first distance of probing from a to-be-backed drilling position of the circuit board when a probing device detects a first surface of the circuit board, drilling a first drilling hole, obtaining a second distance of probing from the probing device when the probing device detects an internal signal layer in the first drilling hole, performing wet film filling on the first drilling hole, determining a third distance between the first surface of the circuit board and the internal signal layer according to the first distance and the second distance, drilling a second drilling hole from a second surface of the circuit board and corresponding to the first drilling hole position area, and enabling the second drilling hole to penetrate through the circuit board along the thickness direction of the circuit board; and drilling back drilling holes at the wet film position according to the third distance and the thickness of the electroplated layer, thereby reducing the difficulty of the back drilling hole manufacturing process, realizing the accurate control of the back drilling stub and avoiding the out-of-tolerance abnormality of the back drilling stub caused by uneven thickness of the medium in the inner layer of the circuit board.

Inventors

XIE QUANBIN
HE DONG
WU BINJIE
ZHOU YONG
Wan Huoliang

Assignees

广州广合科技股份有限公司
黄石广合精密电路有限公司
东莞广合数控科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260327

Claims (10)

1. A back drilling manufacturing method of a printed circuit board is characterized by comprising the following steps: providing a circuit board, wherein the circuit board comprises a first surface, a second surface and an internal signal layer, and the first surface and the second surface are oppositely arranged; Acquiring a first downward-extending distance from the detection device to the first surface of the circuit board; Drilling a first drilling hole from a position to be backed-drilled of the circuit board, wherein the first drilling hole is a blind hole; Acquiring a second downward-looking distance from the detection device to an internal signal layer in the first borehole; wet film filling is carried out on the first drilling hole; Determining a third distance between the first surface of the circuit board and the internal signal layer according to the first distance and the second distance; drilling a second drilling hole from the second surface of the circuit board and corresponding to the first drilling hole position area, wherein the second drilling hole penetrates through the circuit board along the thickness direction of the circuit board; carrying out copper deposition electroplating to form an electroplated layer; and drilling a back drilling hole at the wet film position according to the third distance and the thickness of the electroplated layer.
2. The method of fabricating a backside borehole of a printed circuit board according to claim 1, wherein the probing device comprises: the drilling machine comprises a drilling machine main shaft, a detection drilling needle and a pressure sensor; The drill main shaft is connected with the detection drill needle, and the pressure sensor is arranged in the drill main shaft; the drilling machine spindle is used for controlling the lifting of the detection drilling needle, and the pressure sensor is used for detecting the pressure applied to the detection drilling needle.
3. The method of claim 2, wherein the tip of the probe pin comprises a non-metallic material.
4. A method of fabricating a back side borehole of a printed circuit board according to claim 3 wherein the probe pin is polycrystalline diamond or hard ceramic.
5. The method for fabricating a backside borehole of a printed circuit board according to claim 1, wherein, The diameter of the back drilling hole is larger than or equal to that of the first drilling hole, and the diameter of the first drilling hole is larger than that of the second drilling hole.
6. The method for manufacturing the back drilling of the printed circuit board according to claim 1, wherein the method comprises the following steps: And when the first drilling hole is formed, controlling the distance from the tip of the drilling tool to the internal signal layer to be more than or equal to 0 and less than or equal to 10mil.
7. The method of fabricating a back-drilled hole of a printed circuit board according to claim 6, further comprising, after drilling a first drilled hole from a position of the circuit board to be back-drilled: laser ablating the medium in the first borehole to expose the internal signal layer.
8. The method of claim 2, wherein the drill spindle controls the probe drill to stop moving down when the pressure value detected by the pressure sensor is greater than or equal to a set pressure value threshold.
9. The method for manufacturing the back drilling of the printed circuit board according to claim 2, wherein: The diameter of the detection drill point is smaller than that of the first drilling hole, and the length tolerance range of the detection drill point is smaller than +/-10 mu m.
10. A printed circuit board, characterized in that a back drill is produced according to the back drill production method of a printed circuit board according to any one of claims 1-9.

Description

Printed circuit board back drilling manufacturing method and printed circuit board Technical Field The invention relates to the technical field of printed circuit boards, in particular to a back drilling manufacturing method of a printed circuit board and the printed circuit board. Background With the rapid development of the printed circuit board industry, the signal integrity of printed circuit boards is also required to be higher and higher, particularly for high-speed product boards of 56G/112G and above. The high-speed signal product board generally relates to a back drilling manufacturing process, and the length of a back drilling stub directly influences signal transmission quality. The existing back drilling manufacturing process is used for back drilling through the conductive loop formed by the reference layer, the auxiliary hole and the like and the drilling machine, meanwhile, the actual back drilling depth is difficult to accurately obtain due to the influence of uniformity fluctuation of the laminated plate thickness, the back drilling stub length is difficult to accurately control, and the high-speed signal transmission quality is influenced. Disclosure of Invention The invention provides a back drilling manufacturing method of a printed circuit board and the printed circuit board, so as to realize accurate control of the length of a back drilling stub. According to an aspect of the present invention, there is provided a back drilling method of a printed circuit board, the back drilling method of the printed circuit board including: providing a circuit board, wherein the circuit board comprises a first surface, a second surface and an internal signal layer, and the first surface and the second surface are oppositely arranged; Acquiring a first downward-extending distance from the detection device to the first surface of the circuit board; Drilling a first drilling hole from a position to be backed-drilled of the circuit board, wherein the first drilling hole is a blind hole; acquiring a second downward-extending distance when the detection device detects an internal signal layer in the first borehole; wet film filling is carried out on the first drilling hole; Determining a third distance between the first surface of the circuit board and the internal signal layer according to the first distance and the second distance; drilling a second drilling hole from the second surface of the circuit board and corresponding to the first drilling hole position area, wherein the second drilling hole penetrates through the circuit board along the thickness direction of the circuit board; carrying out copper deposition electroplating to form an electroplated layer; and drilling a back drilling hole at the wet film position according to the third distance and the thickness of the electroplated layer. Optionally, the detecting device includes: the drilling machine comprises a drilling machine main shaft, a detection drilling needle and a pressure sensor; The drill main shaft is connected with the detection drill needle, and the pressure sensor is arranged in the drill main shaft; the drilling machine spindle is used for controlling the lifting of the detection drilling needle, and the pressure sensor is used for detecting the pressure applied to the detection drilling needle. Optionally, the tip of the probe pin comprises a non-metallic material. Optionally, the detection drill point adopts polycrystalline diamond or hard ceramic. Optionally, the diameter of the back drilling hole is greater than or equal to the diameter of the first drilling hole, and the diameter of the first drilling hole is greater than the diameter of the second drilling hole. Optionally, when the first drill hole is formed, controlling the distance from the tip of the drill bit to the internal signal layer to be greater than or equal to 0 and less than or equal to 10mil. Optionally, after drilling the first drill hole from the position to be backdrilled of the circuit board, the method further includes: laser ablating the medium in the first borehole to expose the internal signal layer. Optionally, when the pressure value detected by the pressure sensor is greater than or equal to a set pressure value threshold, the drill spindle controls the detection drill point to stop moving downwards. Optionally, the diameter of the probe pin is smaller than the diameter of the first borehole, and the length tolerance range of the probe pin is smaller than +/-10 μm. According to another aspect of the invention, a printed circuit board is provided, and the back drill hole is prepared according to the back drill hole manufacturing method of the printed circuit board in any embodiment. According to the back drilling manufacturing method of the printed circuit board, the first distance of the probing device probing the first surface of the circuit board and the second distance of the probing device probing the internal signal layer in the first drillin