METHOD OF MANUFACTURING MULTILAYER HIGH DENSITY SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To provide a manufacturing method of a multilayer high density, which can inexpensively manufacture the substrate of high density and fine pitch, can simplify the press-fitting procedure and can improve competitive power. SOLUTION: The circuit of a first layer is produced by the high density circuit forming method of a polyimide substrate. The surface circuit of high density thinning is obtained and the circuit is connected/diffused to a base layer. Since second and subsequent layer substrates do not need high density circuits such as the first layer substrate, they are produced by non-high density organic substrates 12 and the effect of a multilayer board is consequently obtained. Then, the cast of a material can remarkably be reduced. A welding projection connecting method is adopted in the connection of the surface layer of the second layer non-high density organic substrate 12 and a welding pad 113 at the base of the polyimide substrate of the first layer. A welding projection 125 is generated in the I/O contact point of the second layer and it is connected to the first layer polyimide substrate 11 by a press-fitting method. Thus, a manufacturing process can be simplified.