Computer Detection of Bent Fingers in Lead Bonding Frames

Abstract

In the production of logic circuits in dual inline packages, various tedious assembly line tasks are performed by human operators using microscopes or television enlargements. One boring and difficult task is the detection of bent fingers in lead bonding frames to which integrated circuit chips are subsequently bonded. Bent fingers can cause stresses which may eventually lead to the failure of circuits. This paper discusses the inspection problem and presents a computerized bent finger detection method which could be adapted to free human operators from this task. More immediately, it presents a method of examining an object and determining whether or not it is in focus based solely on inspection of the object's digitized light intensity profiles.