Method for making copper cylinder on circuit board and circuit board with surface copper cylinders

Abstract

The embodiment of the invention discloses a method for making copper cylinders on a circuit board, comprising the following steps: making first blind holes on the outermost layer of a multilayer substrate; filling and leveling up the first blind holes through galvanizing so as to form the copper cylinders, which can be connected with the second outermost layer of the multilayer substrate, in the first blind holes; and removing the outermost layer at a certain area and depth around the first blind holes through laser ablation to keep the copper cylinders formed in the first blind holes. The embodiment of the invention also provides a corresponding circuit board with surface copper cylinders. By the method disclosed by the embodiment of the invention, the copper cylinders are formed on the outermost layer of the multilayer substrate, the height of the copper cylinders can be kept consistent, the copper cylinders are firm and reliable and cannot be broken or fall off easily, and the operation that a circuit graph is made on a substrate surface is not influenced.

Description

technical field [0001] The invention relates to the technical field of circuit board production, in particular to a method for manufacturing copper pillars on a circuit board and a circuit board with surface copper pillars. Background technique [0002] Packaging technology has higher and higher requirements for soldering. As flip-chip technology has become the current mainstream technology, high-density soldering between chips and packaging substrates has become a key research object. Since the solder joints are getting smaller and smaller, in order to improve the soldering yield and reliability, it is proposed to replace the original plane soldering process with bump soldering. Bump soldering is to form a raised copper pillar on the surface of the package substrate as a soldering point for soldering. Bump soldering can solve the problem of virtual soldering caused by uneven flatness and uneven thickness of solder mask in traditional plane soldering, and can adapt to high-...

AI Technical Summary

Problems solved by technology

Due to the uneven current density during electroplating, the electroplated copper pillars are uneven, and the dry film on the surface of the substrate cannot be leveled. Therefore, the copper pillars produced by this method cannot meet the requirements of modern soldering and packaging.

In addition, since the electroplated copper pillars protrude from the surface of the substrate, they cannot be effectively protected during subsequent processing and are easy to fall off; it is also difficult to make circuit patterns on the substrate surface where the copper pillars are formed, and the substrate space cannot be effectively used

Based on the above series of problems, the process of bump welding by welding copper pillars cannot be applied and promoted

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