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US 6,635,954 B2Granted
Stress reduction feature for LOC lead frame
AssigneeMicron Technology, Inc.
InventorsLarry D. Kinsman, Timothy J. Allen, Jerry M. Brooks
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. The lead frame has stress relief slots formed in the undersides of the lead elements proximate the adhesive to accommodate filler particles lodged between the leads and the active surface of the die during transfer molding of a plastic encapsulant. The increased space created by the slots and flexure in the leads about the slots reduces point stresses on the active surface of the die by the filler particles. The increased flexure in the leads about the slots further enhances the locking of the leads in position with respect to the die.
Claims17
An encapsulated semiconductor die assembly comprising:
- a semiconductor die having an active surface and a plurality of sides;
- at least one adhesive segment having an outer edge and adhering to a portion of said active surface of said semiconductor die;
- and
- a lead frame including a plurality of lead members, at least one lead member of said plurality of lead members having a lead end portion connected to a portion of said 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 at least one lead member including a stress relief portion formed therein, said stress relief portion extending over a portion of said active surface of said semiconductor die, extending along a portion of said length of said at least one lead member at a location between said free end portion and said lead end portion and extending partially through said thickness of said at least one lead member, said stress relief portion formed in said at least one lead member extending along said length of said at least one lead member from a location proximate said outer edge of said at least one adhesive segment to a location proximate a side of said plurality of sides of said semiconductor die, said stress relief portion providing an enlarged space between a lower surface of said at least one lead member and a portion of said active surface of said semiconductor die, said enlarged space allowing plastic having a filler material therein having a particle size distribution and an average particle size diameter within said particle size distribution to flow therethrough without said filler material therein substantially damaging said portion of said active surface of said semiconductor die during an encapsulation process of encapsulating said semiconductor die in said plastic having said filler material therein.
1 more element
An encapsulated semiconductor die assembly comprising:
- a semiconductor die having an active surface and a plurality of sides;
- at least one adhesive segment having an outer edge and adhesively secured to a portion of said active surface of said semiconductor die;
- and
- a lead frame including a plurality of lead members, at least one lead member of said plurality of lead members having a lead end portion connected to a portion of said 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 at least one lead member of said plurality of lead members having a first portion of said length thereof adhered to said active surface of said semiconductor die and having a second portion of said length thereof extending outwardly over said active surface unadhered thereto, said at least one lead member having a stress relief portion formed therein, said stress relief portion extending over a portion of said active surface of said semiconductor die, extending along a portion of said length of said at least one lead member at a location between said free end portion and said lead end portion and extending partially through said thickness of said at least one lead member, said stress relief portion formed in said at least one lead member extending along said length of said at least one lead member from a location proximate said outer edge of said at least one adhesive segment to a location proximate a side of said plurality of sides of said semiconductor die, said stress relief portion providing an enlarged space between a lower surface of said at least one lead member and a portion of said active surface of said semiconductor die, said enlarged space allowing plastic having a filler material therein having a particle size distribution and an average particle size diameter within said particle size distribution to flow therethrough without said filler material therein substantially damaging said portion of said active surface of said semiconductor die during an encapsulation process of encapsulating said semiconductor die in said plastic having said filler material therein.
1 more element
An encapsulated semiconductor die assembly comprising:
- a semiconductor die having an active surface and a plurality of sides;
- at least one adhesive segment having an outer edge thereof, said at least one adhesive segment being connected to said active surface of said semiconductor die;
- and
- a lead frame including a plurality of lead members, at least one lead member of said plurality of lead members having a lead end portion connected to a portion of said 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, wherein a first portion of said length of said at least one lead member is adhered to said semiconductor die by said at least one adhesive segment having said outer edge thereof, said outer edge of said at least one adhesive segment being located substantially parallel to a side of said plurality of sides of said semiconductor die and being located substantially transverse to said length of said at least one lead member, said at least one lead member having a stress relief portion formed therein, said stress relief portion extending over a portion of said active surface of said semiconductor die, extending along a portion of said length of said at least one lead member at a location between said free end portion and said lead end portion and extending partially through said thickness of said at least one lead member wherein said stress relief portion formed in said at least one lead member extends along said length of said at least one lead member from a location proximate a side of said plurality of sides of said semiconductor die to a location proximate said outer edge of said at least one adhesive segment, said stress relief portion providing an enlarged space between a lower surface of said at least one lead member and a portion of said active surface of said semiconductor die, said enlarged space allowing a plastic having a filler material therein having a particle size distribution and an average particle size diameter within said particle size distribution to flow therethrough without said filler material therein substantially damaging said portion of said active surface of said semiconductor die during an encapsulation process of encapsulating said semiconductor die in said plastic having said filler material therein.
1 more element
An encapsulated semiconductor die assembly comprising:
- a semiconductor die having an active surface and a plurality of sides;
- at least one adhesive segment having an outer edge and adhesively secured and thereby connected to a portion of said active surface of said semiconductor die;
- and
- a lead frame including a plurality of lead members, at least one lead member of said plurality of lead members having a lead end portion connected to a portion of said 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 at least one lead member of said plurality of lead members having a first portion of said length thereof adhered to said active surface of said semiconductor die and having a second portion of said length thereof extending outwardly over said active surface unadhered thereto, said at least one lead member having a stress relief portion formed therein, said stress relief portion extending over a portion of said active surface of said semiconductor die, extending along a portion of said length of said at least one lead member at a location between said free end portion and said lead end portion and extending partially through said thickness of said at least one lead member, said stress relief portion formed in said at least one lead member extending along said length of said at least one lead member from a location proximate a side of said plurality of sides of said semiconductor die to a location proximate said outer edge of said at least one adhesive segment, said stress relief portion providing an enlarged space between a lower surface of said at least one lead member and a portion of said active surface of said semiconductor die, said enlarged space allowing a plastic having a filler material therein having a particle size distribution and an average particle size diameter within said particle size distribution to flow therethrough without said filler material therein substantially damaging said portion of said active surface of said semiconductor die during an encapsulation process of encapsulating said semiconductor die in said plastic having said filler material therein in a mold.
1 more element
Dependencies are inferred from the claim text.