PCB capable of detecting depth of back drilling hole and detection method

Abstract

The invention discloses a PCB capable of detecting the depth of a back drilling hole. The PCB is formed by overlapping L1, L2,..., LN layers of boards (N > 2) in sequence; the PCB is provided with test holes. The test holes are through holes; the test holes comprise two short-circuit test holes and two open-circuit test holes; each layer of plate is provided with a circuit; the two short-circuit test holes and the two open-circuit test holes respectively form a communication loop with the circuit; the PCB is provided with at least one through hole A except the test holes, copper is plated in the through hole A, a back drilling hole is formed in the at least one through hole A, and the through hole A is electrically connected with a circuit connected with the short-circuit test holes and acircuit connected with the open-circuit test holes respectively. The invention further provides a detection method capable of detecting the depth of the back drill hole, the size precision of the backdrill hole is improved, the quality of the PCB is ensured, and the quality of the back drill hole is well monitored through a power-on test method.

Description

technical field [0001] The invention relates to the field of PCB boards, in particular to a PCB board capable of detecting the depth of a back-drilled hole and a detection method. Background technique [0002] With the development of the electronics industry, especially the application of HDI high-density and high-speed connection products is becoming more and more widely, the requirements for signal integrity transmission are getting higher and higher, and the back-drilling technology of PCB is also widely used. In order to prevent signal distortion and delay, it is necessary to drill out the metal in the hole without any transmission function at the end of the through hole of the PCB board to maintain signal integrity and not be disturbed. Conventional back drilling technology is used to remove some useless holes to meet high frequency and high speed. performance, but the depth and precision of the back-drilled holes are not easy to grasp. Less or more back-drilled holes w...

AI Technical Summary

Problems solved by technology

In order to prevent signal distortion and delay, it is necessary to drill out the metal in the hole without any transmission function at the end of the through hole of the PCB board to maintain signal integrity and not be disturbed. Conventional back drilling technology is used to remove some useless holes to meet high frequency and high speed. performance, but the depth and accuracy of the back-drilled holes are not easy to grasp. Less or more back-drilled holes will affect the transmission and quality of the PCB board signal, resulting in an increase in defective products and increasing the production cost of the PCB board.

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