Unique fiducial designs for CSP singulation process

Abstract

This paper describes the invention of unique designs of fiducial marks on the ball pad side of substrates for different CSP (Chip Scale Package) integrated circuit package types and sizes. These unique designs on the substrates are related to the saw singulation process in the assembly of this type of packages. The distinct, unique fiducial designs enable the PRS (Pattern Recognition System) of the saw singulation equipment to differentiate between different molded CSP substrates, and stop the operation when the saw program of the equipment doesn't match the expected fiducial design on the substrate. These unique fiducial marks provide an error free solution that prevents loading wrong saw programs or feeding incorrect CSP substrates/packages into the saw singulation equipment. The benefits are that different type and sizes of CSP packages will not be sawn with the wrong dimensions, and that expensive saw singulation equipment parts will not get damaged.