Method for forming lead frame land grid array
A package includes a first plated area, a second plated area, a die attached to the first plated area, and a bond coupling the die to the second plated area. The package further includes a molding encapsulating the die, the bond, and the top surfaces of the first and second plated areas, such that the bottom surfaces of the first and second plated areas are exposed exterior to the package. Additional embodiments include a method of making the package.
1. A method of packaging comprising:
a. plating a plurality of first areas on a metal layer, wherein each of the first areas comprise a first palladium layer, a nickel layer, a second palladium layer and a gold layer, wherein the gold layer is on the metal layer, the second palladium layer is on the gold layer, the nickel layer is on the second palladium layer and the first palladium layer is on the nickel layer such that the gold layer is exposed at the bottom of the first areas when the metal layer is removed;
b. plating a plurality of second areas of the metal layer;
c. mounting one or more dies to each of the first areas plated on the metal layer with an adhesive;
d. bonding at least one wire, the wire coupling each die of the dies to at least one second area;
e. encasing the metal layer, the dies and the plurality of first and second areas in a mold compound thereby forming a molded block;
f. removing the metal layer from the molded block, such that the first and second areas are exposed; and
g. singulating the molded block after removal of the metal layer thereby forming individual packages;
wherein the plurality of second areas are contact pads that are plated such that a different one of the contact pads is adjacent to each side of the one or more dies and has sufficient length such that the contact pad extends along the entire length of the each side of the one or more dies.
2. The method of claim 1 , wherein the first plated area comprises a die attach pad.
3. The method of claim 1 , wherein the first plated area comprises a contact pad.
4. The method of claim 1 , wherein removing the metal layer comprises etching away the metal layer, without removing the plated regions such that the plated regions are exposed at an exterior surface of the package.
5. The method of claim 1 , further comprising testing the molded block.
6. The method of claim 5 , wherein testing the molded block comprises a parallel process for a plurality of devices within the molded block.
7. The method of claim 1 , further comprising singulating a molded package from the molded block.
8. The method of claim 1 , the plating having a plurality of layers comprising palladium, nickel, and gold.
9. The method of claim 1 , further comprising exposing one or more of the second plated areas at a side surface of the package that is non-parallel with the bottom of the package, wherein the second plated area is for forming a contact pad that is accessible at the side surface.
10. The method of claim 1 , further comprising encapsulating the second plated area at a side surface of the package.
11. The method of claim 1 , further comprising plating a plurality of third areas such that each third area extends at least partially around one of the first plated areas, the one of the first plated areas comprising a die pad, the third plated area comprising a band near a perimeter of the die pad.
12. The method of claim 11 , wherein each of the third plated areas comprise a ring surrounding the die pad of the one of the first plated areas.
13. The method of claim 1 , wherein each of the one or more dies have a width dimension greater than a dimension of each of the first plated areas, such that the die overhangs the first plated area.
14. The method of claim 1 , wherein each of the first plated areas comprise a first contact pad, and each of the second plated areas comprise a second contact pad, wherein one of the dies is coupled to the first and second contact pads without the need for a die pad, such that space required by the package is conserved.
15. The method of claim 14 , wherein the size of the package closely approximates the size of the die.
16. The method of claim 1 , wherein the bonding comprises using a bonding wire for coupling the die to the second plated area.
17. The method of claim 1 , wherein the bonding comprises using a solder ball for coupling the die to the second plated area.
18. The method of claim 1 , further comprising forming a plurality of contact pads for forming a row of contact pads near a perimeter of a die pad.
19. The method of claim 1 , further comprising forming a plurality of contact pads surrounding a die pad.
20. The method of claim 19 , further comprising forming a guard band or a guard ring.
21. A method of making a semiconductor device comprising the steps:
a. plating a ring onto a metal substrate, wherein the ring is a continuous band;
b. plating a plurality of contact pads onto the metal substrate, wherein the contact pads at least partially surround the ring;
c. directly coupling a semiconductor die with the ring such that the semiconductor die is not above a die attach pad;
d. mounting a plurality of bondwires to the semiconductor die and the contact pads;
e. at least partially encasing the semiconductor die in a mold compound;
f. etching away the metal substrate, thereby exposing the ring and plurality of contact pads; and
g. singulating the at least partially encased semiconductor die after sacrificing the metal substrate thereby forming an individual package.
22. The method of claim 21 wherein the plurality of contact pads are plated such that a different one of the contact pads is adjacent to each side of the die and has sufficient length such that the contact pad extends along the entire length of the side of the die.
23. A method of making a semiconductor device comprising the steps:
a. plating a plurality of contacts pads onto a metal substrate;
b. attaching a semiconductor die to the metal substrate by applying adhesive between the plurality of contact pads, wherein an outermost perimeter of the semiconductor die is aligned so as to form a line with inner edges of the contact pads, wherein the line is perpendicular to a top surface of the semiconductor device, and further wherein the outermost perimeter of the adhesive is abutted to the inner edges of the contact pads;
c. mounting a plurality of bondwires to the semiconductor die and the contact pads;
d. at least partially encasing the semiconductor die in a mold compound; and
e. sacrificing the metal substrate, thereby exposing the contact pads.
24. The method of claim 1 , wherein the gold layer has a thickness of at least 50 angstroms, the second palladium layer has a thickness of at least 0.1 micrometers, the nickel layer has a thickness of at least 0.5 micrometers and the first palladium layer has a thickness of at least 0.5 micrometers.
25. The method of claim 21 , wherein the ring and the contact pads do not protrude from a bottom surface of the mold compound, and wherein the entirety of the metal substrate is etched away.