Package structure assembly for TVS devices
View Patent ↗Provided herein are package structures including a first lead frame having a first pedestal and a first lead extending from the first pedestal. A first perimeter ridge defines a first recessed area in a first main side of the first pedestal, wherein a die pad is positioned within the first recessed area. The package structure may further include a chip layer having a first main side opposite a second main side, wherein the second main side is in abutment with the first perimeter ridge of the pedestal of the first lead frame. The package structure may further include a clip including a second pedestal and a lead connector extending from the second pedestal, wherein a second perimeter ridge defines a second recessed area in a second main side of the second pedestal, and wherein the second perimeter ridge is in abutment with the first main side of the chip layer.
1 . A package structure, comprising:
a first lead frame including a first pedestal and a first lead extending from the first pedestal, wherein the first pedestal includes a first stepped level extending from a first main side thereof, wherein a first perimeter ridge extends from the first stepped level toward the chip layer and defines a first recessed area in the first stepped level of the first main side of the first pedestal, and wherein a die pad is positioned within the first recessed area;
a chip layer having a first main side opposite a second main side, wherein the second main side is in abutment with the first perimeter ridge of the first pedestal of the first lead frame; and
a clip including a second pedestal and a lead connector extending from the second pedestal, wherein the second pedestal includes a second stepped level extending from a second main side thereof, wherein a second perimeter ridge extends from the second stepped level toward the chip layer and defines a second recessed area in the second stepped level of the second main side of the second pedestal, and wherein the second perimeter ridge is in abutment with the first main side of the chip layer.
2 . The package structure of claim 1 , further comprising a second lead frame connected to the lead connector of the clip.
3 . The package structure of claim 2 , further comprising an encapsulation surrounding the chip layer, wherein the first lead frame and a second lead frame extend through the encapsulation.
4 . The package structure of claim 2 , further comprising a first solder between the first pedestal and the chip layer, wherein the first perimeter ridge and the first recessed area constrain movement of the first solder.
5 . The package structure of claim 4 , wherein the first solder is in direct contact with the die pad and the second main side of the chip layer.
6 . The package structure of claim 2 , further comprising a second solder between the second pedestal and the chip layer, wherein the second perimeter ridge and the second recessed area constrain movement of the second solder.
7 . The package structure of claim 6 , further comprising a third solder between the lead connector and the second lead frame.
8 . The package structure of claim 6 , wherein the chip layer comprises a transient-voltage-suppression (TVS) device.
9 . The package structure of claim 8 , wherein the second solder couples the TVS device and the second pedestal.
10 . A semiconductor package, comprising:
a first lead frame including a first pedestal and a first lead extending from the first pedestal, wherein the first pedestal includes a first stepped level extending from a first main side thereof, wherein a first perimeter ridge extends from the first stepped level toward the chip layer and defines a first recessed area in the first stepped level of the first main side of the first pedestal, and wherein a die pad is positioned within the first recessed area;
a chip layer having a first main side opposite a second main side, wherein the second main side is in abutment with the first perimeter ridge of the first pedestal of the first lead frame; and
a clip including a second pedestal and a lead connector extending from the second pedestal, wherein the second pedestal includes a second stepped level extending from a second main side thereof, wherein a second perimeter ridge extends from the second stepped level toward the chip layer and defines a second recessed area in the second stepped level of the second main side of the second pedestal, and wherein the second perimeter ridge is in abutment with the first main side of the chip layer.
11 . The semiconductor package of claim 10 , further comprising:
a second lead frame connected to the lead connector of the clip; and
an encapsulation surrounding the chip layer, wherein the first lead frame and a second lead frame extend outside the encapsulation.
12 . The semiconductor package of claim 11 , further comprising a first solder between the first pedestal and the chip layer, wherein the first perimeter ridge and the first recessed area constrain movement of the first solder, and wherein the first solder is in direct contact with the die pad and the second main side of the chip layer.
13 . The semiconductor package of claim 11 , further comprising a second solder between the second pedestal and the chip layer, wherein the second perimeter ridge and the second recessed area constrain movement of the second solder.
14 . The semiconductor package of claim 13 , further comprising a third solder between the lead connector and the second lead frame.
15 . The semiconductor package of claim 13 , wherein the chip layer comprises a transient-voltage-suppression (TVS) device.
16 . The semiconductor package of claim 15 , wherein the second solder couples the TVS device and the second pedestal.
17 . A method of forming a package structure, comprising:
providing a first lead frame including a first pedestal and a first lead extending from the first pedestal, forming a first stepped level in a first main side of the first pedestal, wherein a first perimeter ridge extends from the first stepped level toward a chip layer to be mounted thereon and defines a first recessed area in the first stepped level of the first main side of the first pedestal, and wherein a die pad is positioned within the first recessed area; connecting a chip layer to the first lead frame, wherein the chip layer includes a first main side opposite a second main side, and wherein the second main side is in abutment with the first perimeter ridge of the first pedestal of the first lead frame; and
connecting a clip to the chip layer, wherein the clip includes a second pedestal and a lead connector extending from the second pedestal, forming a second stepped level in a second main side of the second pedestal, wherein a second perimeter ridge extends from the second stepped level toward the chip layer and defines a second recessed area in the second stepped level of the second main side of the second pedestal, and wherein the second perimeter ridge is in abutment with the first main side of the chip layer.
18 . The method of claim 17 , further comprising providing a first solder between the first pedestal and the chip layer, wherein the first perimeter ridge and the first recessed area constrain movement of the first solder, and wherein the first solder is in direct contact with the die pad and the second main side of the chip layer.
19 . The method of claim 17 , further comprising providing a second solder between the second pedestal and the chip layer, wherein the second perimeter ridge and the second recessed area constrain movement of the second solder.
20 . The method of claim 19 , further comprising coupling a transient-voltage-suppression (TVS) device of the chip layer to the second pedestal using the second solder.