Manufacturing process of back-drilled zero residual copper pile on PCB substrate

Abstract

The invention provides a manufacturing process of a back-drilled zero residual copper pile on a PCB substrate. The specific process includes the following steps: preparing an N-layer circuit board, wherein N>=4; longitudinally presetting A groups of disconnecting layers at a selected position, wherein A>=1; placing a soluble material on upper and lower sides of the disconnecting layers; pressing araw material in the step a into a PCB semi-finished product; mechanically drilling the PCB semi-finished product; coating the drilled holes with a polymer conductive film; dissolving the soluble material to remove to the polymer conductive film on a soluble sheet; electroplating and metallizing the remaining polymer conductive film through electroplating; and subjecting the semi-finished productin the f step to pattern plating and film stripping and etching. In the existing design scheme, through-holes that transmit a single signal are formed through mechanical back-drilling, and has a certain length of residual copper pile which interfere with signal transmission on high speed PCBs. The process can form multi-functional holes through a chemical method, a zero-residue copper pile can beachieved, which can meet the signal transmission of the high-speed PCBs. The method can be used to make back holes or multifunctional holes, and the same hole can transmit signals of two or more networks.

Description

technical field [0001] The invention relates to the field of circuit substrate optimization, in particular to a manufacturing process of back-drilling zero residual copper piles on a PCB substrate. Background technique [0002] With the development of data communication and multimedia service requirements, users are increasingly dissatisfied with a single communication method that only communicates through voice. People hope that mobile communication systems can provide a wider range of services, such as Internet access, image transmission, and video on demand. , data mutual transmission, and even watch data or multimedia services such as TV programs in real time. At the same time, it is also hoped to develop from the current communication between people to the communication between people and machines, and even between machines and machines. For this reason, the fourth generation mobile communication (4G) that meets the needs of mobile data, mobile computing and mobile mult...

AI Technical Summary

Problems solved by technology

If the excess copper is not removed, when the frequency of the circuit signal increases to a certain height (usually above 5G), the excess copper plating is equivalent to the antenna, generating signal radiation that interferes with other surrounding signals, and in severe cases will affect the circuit For the normal operation of the system, in order to reduce this impact, the stub of the inner layer wiring must be made as short as possible, the shorter the impact, the less impact, but the defect of mechanical back drilling is that it cannot completely remove useless copper

It has at least 2mil or more residual copper (Stub), and it will generate noise interference to varying degrees when transmitting high-speed signals, which will cause signal attenuation loss

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