Research of design and processing technology of CQFP package with 0.40mm pitch

Compared with the general package, 0.40mm pitch ceramic package has smaller lead pitch, the smaller welding area between the lead and the package and the thinner thickness of the lead. Therefore The lead fastness and the processing and forming of the lead are the key points for the design and processing of the 0.40mm pitch package. The main content of This article are carry out critical technology and research, such as the design of the lead fastness, The molding of ultra-thin lead wire and high precision brazing, mastered the etching of 0.40 mm pitch wire processing and molding process, conducting lead section morphology research, implements the 0.40 mm pitch lead processing, has the high precision brazing technology, satisfies the requirement of 0.40 mm pitch lead fastness. On the premise of satisfying the device dimensions requirements, the lead welding length should be increased as much as possible to enlarge the welding area. At the same time, the airfoil lead dog-leg welding structure is adopted to ensure the lead welding strength through the shape design of lead solder to form a reasonable angle. In this paper, based on the existing high-density multi-layer ceramic technology system, a ceramic package with the pitch of 0.40mm was successfully developed in China for the first time. The minimum pitch of domestic ceramic package was reduced from the current 0.50mm to 0.40mm, so as to realize the research and application of CQFP ceramic package with a pitch of 0.40mm.With this research, it give the rules of design welding pad, lead and lead solder of 0.40mm pitch CQFP ceramic package, the development ability of 0.40mm pitch lead ceramic package can be improved, and similar ceramic package can be designed and manufactured quickly to meet the needs of different users.