Semiconductor dies are manufactured with a plurality of bonding pads spaced around their periphery in a more or less uniform configuration. To complete the semiconductor die, a lead (sometimes called an inner lead) is bonded to each of the pads. These leads may then be bonded to yet another set of more rigid leads (outer leads). Thereafter, the die and leads are encapsulated. The reason for using both inner and outer leads is that the typical semiconductor die cannot withstand the head and pressure necessary to directly bond the structurally larger outer leads to the pads.
To increase production and yield, the semiconductor industry has commenced using film-carrier techniques in place of the more widely used wire-bonding technique. A film-carrier consists of a strip of film of foil having sprocket holes at its outer edges which incorporates the lead frame. The leads are simultaneously bonded to the bonding pads on the die by a bonder. The sprocket holes along the sides of the film-carrier cooperate with a plurality of pawls to advance the film-carrier after the die has been bonded and also to position the lead frame precisely over the die at the bonding site.
In co-pending application Ser. No. 510,207 filed Sept. 30, 1974, a hitch feed and guide assembly for displacing the film-carrier to sequentially position each set of leads over the die and retain the same in position for alignment and bonding is disclosed. In that application the pawls included in the hitch feed assembly only serve to position the lead frames in the longitudinal direction. Separate biasing means are provided to align the lead frame in the lateral direction. The present invention is an improvement over the disclosed hitch feed and guide assembly wherein the pawl means align the film-carrier in both the longitudinal and lateral directions at the bonding site.
USPTO Backgrounds
USPTO Backgrounds