Lead frame design for burr-free singulation of molded array packages

Abstract

A semiconductor device exhibiting a lower incidence of burrs forming on its contacts during the singulation process. The semiconductor device includes a die which is electrically connected to a set of contacts wherein each contact has a contact surface and a non-contact surface. Each contact surface of the contacts contains a recessed region filled with a first deposit of molding material. The die and the non-contact surfaces of the contacts are encapsulated with a second deposit of molding material. The semiconductor device is singulated from a molded lead frame by guiding a saw blade through recessed regions formed on the contact surface of the contacts. The molding material in the recessed regions creates a “buffer zone” which separates the path of the saw blade from the contact surface of the contacts. As a result, the formation of burrs is reduced because the sides of the saw blade are no longer in contact with the contact surface and are therefore unable to pull the contact surface into a burr formation. The molding material also prevents the contact material at the bottom of the recessed region, on the newly cut surface of the contact, from being pulled above the contact surface of the contact. The molding material in the recessed region accomplishes this by acting as a barrier which blocks the movement of contact material which may be pulled.