Feasibility of surface activated bonding for ultra-fine pitch interconnection-a new concept of bump-less direct bonding for system level packaging

In the present study a method of ultra-high density interconnection, the surface activation (SAB) method is introduced. Also for the next generation of packaging, which might bridge to global interconnection on chip, a concept of bump-less bonding is proposed. The bumpless bonding will be especially suitable and inevitable for ultra-high density interconnection when it will convert the range of μm size. For such bonding requires at the same time, combinations of a ultra-thin chip and a flexible substrate. The surface activated bonding method enables the metals and non-metallic materials to be bonded at room temperature only by contact. Some fundamental experiments and preliminary results of examination of the feasibility of the method for Cu and Cu direct bonding are presented