Backside wafer alignment methods
Implementations of a method for wafer alignment may include: providing a wafer having a first side and a second side and forming a seed layer on a second side of the wafer. The method may include applying a glop to the seed layer at two or more predetermined points and plating a metal layer over the seed layer and around the glop. The method may include removing the glop to expose the seed layer and etching the seed layer to expose a plurality of alignment features on the second side of the wafer.
1. A method for wafer alignment, the method comprising:
providing a wafer comprising a first side and a second side;
forming a seed layer on a second side of the wafer;
applying a glop to the seed layer at two or more predetermined points;
plating a metal layer over the seed layer and around the glop;
removing the glop to expose the seed layer;
etching the seed layer to expose a plurality of alignment features in the wafer.
2. The method of claim 1 , further comprising using the plurality of alignment features to align the wafer for singulation.
3. The method of claim 1 , wherein applying the glop further comprises using one of a stencil, a motor controlled dispenser, or a spray coater.
4. The method of claim 1 , wherein the metal layer comprises one of gold, copper, nickel, or any combination thereof.
5. The method of claim 1 , wherein the glop comprises, photoresist, resin, or polymeric material.
6. A method for wafer alignment, the method comprising:
providing a wafer comprising one or more die streets on a first side of the wafer and a seed metal layer on a second side of the wafer;
applying a glop to an area of the second side of the wafer corresponding with the one or more die streets on the first side of the wafer;
forming a layer of metal on the seed metal layer; and
etching the seed metal layer to expose two of the one or more die streets, the two of the one or more die streets each comprising a plurality of alignment features therein.
7. The method of claim 6 , further comprising:
aligning the wafer using an infrared camera; and
singulating the wafer into a plurality of die.
8. The method of claim 6 , wherein applying the glop further comprises using one of a stencil, a motor controlled dispenser, or a spray coater.
9. The method of claim 6 , wherein the metal layer comprises one of gold, copper, nickel, or any combination thereof.
10. The method of claim 6 , wherein the glop comprises, photoresist, resin, or polymeric material.
11. A method for wafer alignment, the method comprising:
providing a wafer comprising a first side and a second side;
applying a wafer backside coating to a second side of the wafer;
applying a glop to the wafer backside coating at two or more predetermined points;
plating a metal layer over the wafer backside coating and around the glop;
removing the glop to expose the wafer backside coating; and
removing the wafer backside coating to expose a plurality of alignment features in the wafer.
12. The method of claim 11 , further comprising:
aligning the wafer using an infrared camera; and
singulating the wafer into a plurality of die.
13. The method of claim 11 , wherein applying the glop further comprises using one of a stencil, a motor controlled dispenser, or a spray coater.
14. The method of claim 11 , wherein the metal layer comprises one of gold, copper, nickel, or any combination thereof.
15. The method of claim 11 , wherein the glop comprises, photoresist, resin, or polymeric material.
16. The method of claim 11 , wherein the wafer backside coating is a seed metal layer.
17. The method of claim 16 , wherein removing the seed metal layer comprises etching.
18. The method of claim 11 , wherein the wafer backside coating is opaque.
19. The method of claim 11 , wherein the metal layer comprises one of metal, oxides, or polymeric materials.