Packaged integrated circuit having large solder pads and method for forming
View Patent ↗A package substrate has a die mounted on a first side. One or more inner solder pads are on an inner portion of a second side. A perimeter of the inner portion is aligned with a perimeter of the die. The one or more inner solder pads are the only solder pads on the inner portion. The one or more inner solder pads number no more than five. A plurality of outer solder pads are on an outer portion of the second side. An average of areas of the one or more inner solder pads is at least five times an average of areas of the one or more inner solder pads. The plurality of outer solder ball pads are for receiving solder ball balls. The outer portion is spaced from the perimeter of the inner portion. The outer portion and the inner portion are coplanar.
1. A packaged integrated circuit, comprising:
a package substrate;
a die mounted to a first major surface of the package substrate;
one or more inner solder pads on an inner portion of a second major surface of the package substrate, wherein the second major surface is opposite the first major surface, a perimeter of the inner portion is aligned with a perimeter of the die, the one or more inner solder pads are the only solder pads on the inner portion, the one or more inner solder pads number no more than five, and an average of areas of the one or more inner solder pads is an inner average; and
a plurality of outer solder ball pads on an outer portion of the second major surface that comprise all of the solder ball pads on the second major surface exclusive of the one or more inner solder pads, wherein an average of areas of the plurality of outer solder ball pads is an outer average, the inner average area is at least five times the outer average, the plurality of outer solder ball pads are for receiving solder balls, the outer portion is spaced from the perimeter of the inner portion, and the outer portion and the inner portion are coplanar.
2. The packaged integrated circuit of claim 1 , wherein each of the one or more inner solder pads are non-circular.
3. The packaged integrated circuit of claim 1 , wherein each of the one or more inner solder pads is for carrying a power supply voltage.
4. The packaged integrated circuit of claim 3 , wherein the power supply voltage is ground.
5. The packaged integrated circuit of claim 4 further comprising solder on the outer solder ball pads and the one or more inner solder pads, wherein an average volume of solder on the one or more inner solder pads is at least five times an average volume of solder on the outer solder ball pads.
6. The packaged integrated circuit of claim 5 , wherein a height of the solder on the outer solder ball pads exceeds a height of the solder on the one or more inner solder pads.
7. The packaged integrated circuit of claim 6 being attached to a printed circuit board, wherein the printed circuit board has outer solder joints attached to the solder on the outer solder ball pads and inner solder joints attached to the solder on the inner solder ball pads, wherein the inner solder joints extend further from surface of the printed circuit board than the outer solder joints extend from the surface of the printed circuit board.
8. The packaged integrated circuit of claim 1 , wherein the one or more inner solder pads number four.
9. The packaged integrated circuit of claim 1 , wherein the die is electrically attached to the one or more inner solder pads.
10. The packaged integrated circuit of claim 1 , wherein:
the die is electrically attached to the one or more inner solder pads and the outer solder ball pads through the package substrate; and
the die is covered with an encapsulant.
11. A method of forming a packaged integrated circuit using a package substrate, comprising:
forming a plurality of outer solder ball pads and one or more inner solder pads on a first major surface of the package substrate, wherein:
the inner solder pads are in an inner portion of the first major surface;
a perimeter of the inner portion is aligned with a perimeter of a die region on a second major surface of the package substrate opposite the first major surface;
the one or more inner solder pads are the only solder pads on the inner portion;
the one or more inner solder pads number no more than five;
an average of areas of the one or more inner solder pads is an inner average;
the output solder ball pads are in an outer portion of the first major surface outside the perimeter of the inner portion;
the outer solder ball pads comprise all of the solder pads on the first major surface exclusive of the one or more inner solder pads;
an average of areas of the plurality of outer solder ball pads is an outer average;
the inner average area is at least five times the outer average;
the plurality of outer solder ball pads are for receiving solder balls;
the outer portion is spaced from the perimeter of the inner portion; and
the outer portion and the inner portion are coplanar; and
mounting a die on the second major surface in the die region.
12. The method of claim 11 , further comprising forming soldering flux on the one or more inner solder pads and the outer solder ball pads.
13. The method of claim 12 , further comprising placing solder balls on the soldering flux that is on the one or more inner solder pads and the outer solder ball pads.
14. The method of claim 13 , wherein the placing solder balls is further characterized by placing an average of at least five solder balls on the one or more inner solder pads.
15. The method of claim 14 , further comprising reflowing the solder balls.
16. The method of claim 15 , further comprising coupling the one or more inner solder pads to the die to provide a power supply to the die.
17. The method of claim 15 , further comprising encapsulating the die.
18. The method of claim 15 , further comprising attaching the packaged integrated circuit to a printed circuit board after the reflowing, the attaching comprising coupling the solder balls that have been reflowed to the printed circuit board.
19. A packaged integrated circuit, comprising:
a package substrate having a first major surface and a second major surface;
a die attached to the first major surface, a perimeter of the die defining an inner portion of the package substrate on the second major surface;
a plurality of inner solder pads on the inner portion, wherein the plurality of inner solder pads is all of the solder pads in the inner portion, is no more than five solder pads, and has a first average area; and
a plurality of outer solder pads that comprise all of the solder pads different from the plurality of inner solder pads on the second major surface, wherein the solder pads are for receiving solder balls, are on the second major surface, and have a second average area, wherein the first average area is at least five times the second average area.
20. The packaged integrated circuit of claim 19 , wherein the plurality of inner solder pads are for carrying ground to the die.