A method of making a stepped hole

Abstract

The invention discloses a method for making a stepped hole, which comprises the following steps: making an inner layer circuit on a core board, making a copper plate at a position corresponding to a large hole on one surface of the core plate, and making a copper plate around the copper plate Make three alignment targets; laminate the outer copper foil and the core board sequentially through the prepreg and press them into a production board; drill the first alignment target hole on the large hole surface of the production board at the position corresponding to the alignment target; Calculate the expansion and contraction coefficient of the production board, and then drill a large hole on the large hole surface of the production board; drill the second alignment target hole at the position corresponding to the alignment target on the small hole surface of the production board; calculate the expansion and contraction coefficient, and then drill a small hole on the small hole surface of the production board; form a plated hole pattern on the production board, and then remove the copper plate at the bottom of the hole by etching, so that the large hole and the small hole are connected up and down to form a ladder hole. The method of the invention utilizes the alignment method of multiple target points in the inner layer, which greatly improves the alignment problem of drilling holes on the front and back sides of the board.

Description

technical field [0001] The invention relates to the technical field of manufacturing printed circuit boards, in particular to a method for manufacturing stepped holes. Background technique [0002] At present, in the process of multi-layer PCB development, more and more customers have proposed the production of high-precision stepped holes, but for the existing mechanical drilling, the size of the hole cannot be less than 0.1mm, which seriously limits the small size of the customer's PCB design. To meet the requirements of globalization and integration, some companies currently use laser drilling to improve the miniaturization of stepped holes, but they are also facing alignment problems. [0003] At present, there are two main production processes of stepped holes. The first is to drill small holes first and then drill large holes through back drilling to form stepped holes. The second is to drill large holes with controlled depth on both sides of the board. And the small ...

AI Technical Summary

Problems solved by technology

[0005] 1. The first method is prone to various quality problems such as burrs and hole plugging;

[0006] 2. In the second method, two different sets of holes are used as the positioning holes when drilling holes on the front and back sides, and deviations are prone to occur during the drilling process. The holes on the front and back sides are misaligned, and there is a problem of poor alignment.