Underfill coating for LOC package
AssigneeMicron Technology, Inc.
InventorWalter L. Moden
Life of this patent
Estimating the term…
Abstract
An LOC die assembly is disclosed including a die dielectrically adhered to the underside of a lead frame. An underfill material is introduced between each lead finger and semiconductor die, extending from the bonding location of the die and the edge of the die, in order to prevent filler particles from lodging between the leads and the active surface of the die during transfer molding of a plastic encapsulant. The seal created by P the underfill material reduces point stresses on the active surface of the die usually caused by the filler particles. The decreased flexure in the leads further enhances the locking of the leads in position with respect to the die.
Claims13
A semiconductor die assembly, said semiconductor die assembly comprising:
- a semiconductor die having an active surface having bonds pads thereon and having a plurality of sides;
- a lead frame including a plurality of lead members, at least one lead member of said plurality of lead members having longitudinal edges, having a top surface, having a lead end portion connected to a portion of the lead frame, having a length, having a thickness, and having a free end portion extending over a portion of said active surface of said semiconductor die, said extending free end portion causing a gap to be formed between said at least one lead member of said plurality of lead members and said active surface of the semiconductor die;
- at least one adhesive segment disposed between at least a portion of said lead end portion of said at least one lead member of said plurality of lead members and substantially adhering to a portion of said active surface of said semiconductor die;
- and
- an underfill material substantially filling the gap formed between said active surface of the semiconductor die and said at least one lead member of said plurality of lead members, said underfill material substantially covering said longitudinal edges and top surface of said at least one lead member of said plurality of lead members, said underfill material preventing flow of an encapsulant material into the gap;
- and said encapsulant material encapsulating portions of said semiconductor die and said plurality of end members.
Dependencies are inferred from the claim text.