The difficulty of thick film screen printing process for AMB CCL lies in maintaining high consistency of printing film thickness
The AMB ceramic coated copper laminate is a high-performance circuit board that used for complex circuit design and high-demand process applications. It possesses advantages such as high thermal conductivity and strong copper layer adhesion, making it suitable for aluminum nitride and silicon nitride ceramic substrates.
In production of CCL, it is easy to cause the copper layer to peel off from the ceramic surface at high temperatures due to the lack of bonding material between copper and ceramics.This drawback makes it impossible to meet the requirements for higher temperatures, high power, high heat dissipation, and high reliability in packaging.Consequently, with its higher reliability, AMB technology gradually becomes the mainstream application.
AMB Process Introduction
What is AMB? It is an active metal brazing process technology that uses thick film screen printing to print the active solder on the surface of a ceramic substrate, and then places a copper foil layer on both sides of the ceramic substrate coated with metal solder (the copper foil layer provides a conductive path for electronic component connection) to form a copper solder ceramic solder copper structure, which is then vacuum sintered to melt the solder and form a solid welding connection with the copper foil layer. After undergoing electroplating, circuit diagram production, solder mask printing, surface treatment, and other processes, a copper clad plate is finally formed.
The printing difficulties of AMB process
In the process of manufacturing AMB , it must be required the thick-film screen printing technology both the solder printing and solder mask layers . Solder printing involves printing onto the surface of the ceramic. If there are issues with uneven or missing prints, during vacuum sintering, the solder may not adequately cover these areas, resulting in voids, low interface bonding strength, and poor adhesion. This significantly affects the reliability of the ceramic-covered copper boards.
The Solder resistance printing mainly provides insulation protection for areas on circuit boards that do not require welding. It covers regions such as pads, traces, and gaps between circuit lines. During the printing process, uneven coverage of solder mask gaps can lead to issues such as solder bridging, short circuits, and fractures.
The Solder and solder resist printing are both crucial processes, especially the stability of the solder to achieve vacuum sintering conditions, thereby improving product reliability.
