Method for lead attachment to pellets mounted in wafer alignment

Claim 2

A process for fabricating a semiconductor device comprising providing a semiconductor wafer containing a plurality of integrally joined semiconductor pellet portions with each of the pellet portions having a plurality of contact pads associated therewith, sub-dividing the wafer to separate the pellet portions into discrete, laterally separated pellets, during sub-dividing and thereafter mounting the pellets so that their original relative orientation in the wafer is preserved, positioning a first set of external leads in registration with the contact pads present on one pellet, simultaneously bonding each of the contact pads on the one pellet to each of the registered external leads, and applying a lifting force to the external leads bonded to the one pellet to lift it from its laterally spaced, wafer aligned mounting with respect to adjacent pellets.

Claim 3

A process according to claim 1 in which during the step of sub-dividing V-shaped grooves are formed between adjacent pellets with the grooves progressively diminishing in width toward the major pellet surfaces carrying contact pads so that the pellets may be readily lifted from their mountings when external leads are attached.

Claim 4

A process according to claim 1 in which the step of mounting comprises molding a mounting material about the wafer so that the molding material is capable of holding the pellets in the desired alignment and maintaining the contact pads free of molding material to facilitate subsequent external lead attachment.

Claim 5

A process according to claim 1 in which the step of mounting is accomplished by the use of a molding material which can be heated to a temperature of 300* C during external lead attachment without deleterious effect to the pellets.

Claim 6

A process according to claim 1 in which bonding is accomplished by bringing a heated bonding tool into engagement with only those portions of the external leads that overlie the one pellet and using the bonding tool to simultaneously heat the external leads and bring them into engagement with the contact pads.

Claim 7

A process according to claim 1 in which the mounted pellets remaining after removal of the one pellet are repositioned so that a second pellet, a second set of external leads, and a heatable bonding tool are brought into vertical alignment and the second set of external leads are bonded to the second pellet in a manner identical to the bonding of the first set of external leads to the one pellet.

Claim 8

A process according to claim 1 in which successive sets of external leads are sequentially bonded to the pellets with each pellet being removed from its mounting when bonding is completed.

Claim 9

A process according to claim 1 in which the pellet portions are located in a regularly spaced manner within the wafer and the pellets formed from the wafer are mounted to preserve the original wafer spacing.

Claim 10

A process according to claim 1 in which bonding is accomplished by bringing a heatable bonding tool into engagement with only those portions of the external leads that overlie the one pellet, aligning successive sets of external leads with the bonding tool in a desired vertical alignment, and successively indexing the pellets into vertical alignment with the bonding tool and external leads so that each set of external leads overlies the contact pads of an aligned pellet, the indexing being substantially simplified by reason of the retention by the pellets of their original wafer alignment.

Claim 11

A process for attaching external leads to each of a plurality of monolithic integrated circuits comprising providing a semiconductor wafer containing therein a plurality of regularly aligned identical monolithic integrated circuit portions with each of the monolithic integrated circuit portions having a plurality of contact pads associated therewith, sub-dividing the wafer to separate The monolithic integrated circuit portions into laterally spaced monolithic integrated circuits, mounting the monolithic integrated circuits so that their contact pads are exposed and accessible for bonding while at all times retaining the wafer alignment of the monolithic circuits with respect to each other, positioning each of the external leads for one monolithic integrated circuit in overlying relation with the contact pads thereof, positioning a heatable bonding tool having a lateral extent substantially corresponding to that of the one monolithic integrated circuit so that it overlies the monolithic integrated circuit, each of its contact pads, and each of the external leads at the location at which they overlie the contact pads, moving the heatable bonding tool toward the monolithic integrated circuit so that all of the external leads are engaged by the bonding tool and simultaneously brought into engagement with the contact pads, simultaneously transferring heat from the bonding tool to each of the contact pads and external leads so that the external leads and contact pads are bonded together simultaneously at their points of engagement, removing the heatable bonding tool from engagement with the external leads, applying a lifting force to the external leads bonded to the one monolithic integrated circuit to lift it from its laterally spaced, wafer aligned mounting with respect to adjacent identical monolithic integrated circuits, and in like manner bonding additional external leads to additional monolithic integrated circuits by successively bringing additional external leads and additional mounted monolithic integrated circuits into alignment with the heatable bonding tool.

Claim 12

A process for attaching external leads to each of a plurality of monolithic integrated circuits comprising providing a semiconductor wafer containing therein a plurality of regularly aligned identical monolithic integrated circuit portions with each of the monolithic integrated circuit portions having a plurality of contact pads associated therewith, sub-dividing the wafer to separate The monolithic integrated circuit portions into laterally spaced monolithic integrated circuits, mounting the monolithic integrated circuits so that their contact pads are exposed and accessible for bonding while at all times retaining the wafer alignment of the monolithic circuits with respect to each other, positioning each of the external leads for one monolithic integrated circuit in overlying relation with the contact pads thereof, positioning a heatable bonding tool having a lateral extent substantially corresponding to that of the one monolithic integrated circuit so that it overlies the monolithic integrated circuit, each of its contact pads, and each of the external leads at the location at which they overlie the contact pads, moving the heatable bonding tool toward the monolithic integrated circuit so that all of the external leads are engaged by the bonding tool and simultaneously brought into engagement with the contact pads, simultaneously transferring heat from the bonding tool to each of the contact pads and external leads so that the external leads and contact pads are bonded together simultaneously at their points of engagement, removing the heatable bonding tool from engagement with the external leads, applying a lifting force to the external leads bonded to the one monolithic integrated circuit to lift it from its laterally spaced, wafer aligned mounting with respect to adjacent identical monolithic integrated circuits, and in like manner bonding additional external leads to additional monolithic integrated circuits by successively bringing additional external leads and additional mounted monolithic integrated circuits into alignment with the heatable bonding tool.