Inner Layer Monitoring Structure of Multilayer Printed Circuit Board

Abstract

The invention discloses an internal layer monitoring structure of a multilayer printed circuit board. The lengthways laminated structure of a working sheet of the multilayer printed circuit board comprises an external layer and multiple internal layers; the plane layout of the working sheet of the multilayer printed circuit board is that multiple circuit board single sheets are arranged; a plurality of sheet-cutting holes are formed in the edge of the working sheet; the sheet-cutting holes are through holes which run through the internal layers and the external layer; the inner surface of each sheet-cutting hole is covered with a copper sheet; the external layer of the working sheet, which is located at the periphery of the sheet-cutting holes, is provided with an external copper ring; the external copper ring is connected with the copper sheet located in each sheet-cutting hole; each internal layer of the working sheet, which is located at the periphery of the sheet-cutting holes, is provided with an internal copper ring; each internal copper ring is connected with the copper sheet in each sheet-cutting hole; the width of each internal copper ring is the maximum acceptable value of the deviation of the internal layers. When internal layer monitoring is needed, the sheet-cutting holes are taken off and cut off by using a sheet punching machine; besides the conventional internal lay data monitoring, whether the internal layers are in poor alignment can be judged through observing whether the sheet-cutting holes are located in the internal copper rings.

Description

technical field [0001] The invention belongs to the field of in-board quality monitoring of printed circuit boards, and in particular relates to a structure of a slicing hole. Background technique [0002] Multi-layer circuit boards are generally produced in joints, and the full-page work sheet generally includes dozens or even hundreds of circuit boards. For example, a memory stick circuit board is generally a work piece composed of 108 memory stick circuit boards. produced simultaneously. In order to assist in the quality control of the inner layer, several slicing holes are generally designed on the edge of the working piece. The slicing hole is a through hole that runs through the working piece. The shape and structure of the slicing hole fully reflect the situation of the circuit board on the working piece. , when it is necessary to monitor the quality of the inner layer, it is necessary to use a punching machine to remove the entire slicing hole from the working sheet...

AI Technical Summary

Problems solved by technology

[0003] However, although the current slicing hole can reflect some data of the inner layer, it cannot reflect the alignment between layers, that is, the defect of interlayer offset cannot be reflected at the slicing hole.

Currently, perspective machines are mostly used to detect interlayer offsets, and position scanning is performed on the positioning points on the work sheet to determine the offset. However, this detection method is slightly more expensive.

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