Method to form a via
View Patent ↗A method for forming a via, comprising (a) providing a structure comprising a mask ( 210 ) disposed on a semiconductor substrate ( 203 ), wherein the structure has an opening ( 215 ) defined therein which extends through the mask and into the substrate, and wherein the mask comprises a first electrically conductive layer; (b) depositing a second electrically conductive layer ( 219 ) such that the second conductive layer is in electrical contact with the first conductive layer, the second conductive layer having a first portion which extends over the surfaces of the opening and a second portion which extends over a portion of the mask adjacent to the opening; (c) removing the second portion of the second conductive layer; and (d) depositing a first metal ( 221 ) over the first portion of the second conductive layer.
1. A method for making a semiconductor device, comprising:
providing a structure comprising a mask disposed on a semiconductor substrate, wherein the structure has an opening defined therein which extends through the mask and into the substrate, and wherein the mask comprises a first electrically conductive layer sandwiched between first and second dielectric layers, and wherein the first electrically conductive layer, the first dielectric layer and the second dielectric layer are coextensive;
depositing a second electrically conductive layer such that the second conductive layer is in electrical contact with the first conductive layer, the second conductive layer having a first portion which extends over the surfaces of the opening and a second portion which extends over a portion of the mask adjacent to the opening;
removing the second portion of the second conductive layer; and
depositing a first metal over the first portion of the second conductive layer.
2. The method of claim 1 , wherein the second conductive layer comprises a metal seed layer.
3. The method of claim 2 , further comprising forming a barrier layer having a first portion which extends over the surfaces of the opening and a second portion which extends over a portion of the mask adjacent to the opening, wherein the barrier layer is in electrical contact with the first conductive layer, and wherein the step of removing the second portion of the second conductive layer also removes the second portion of the barrier layer.
4. The method of claim 3 , wherein the seed layer is deposited over the barrier layer.
5. The method of claim 4 , wherein the barrier layer is a metal layer.
6. The method of claim 2 , wherein the seed layer comprises copper, and wherein the first metal comprises copper.
7. The method of claim 1 , wherein the first and second conductive layers are metal layers.
8. The method of claim 1 , wherein the second portion of the second conductive layer is removed from the portion of the mask adjacent to the opening through chemical mechanical polishing (CMP).
9. The method of claim 1 , wherein the mask comprises a first dielectric layer disposed between the first conductive layer and the substrate.
10. The method of claim 9 , wherein the mask further comprises a second dielectric layer, and wherein the layer is disposed between the first and second dielectric layers.
11. The method of claim 10 , wherein the first and second dielectric layers comprise tetraethylorthosilicate (TEOS).
12. The method of claim 1 wherein, prior to deposition of the second conductive layer, a dielectric layer is formed over the surfaces of the opening.
13. The method of claim 12 , wherein the dielectric layer is formed by a plasma nitridation step.
14. The method of claim 1 , wherein the first metal is deposited by electrochemical deposition.
15. The method of claim 1 , wherein the semiconductor substrate is a wafer, and wherein the first conductive layer is disposed between first and second dielectric layers.
16. The method of claim 15 , wherein the first metal is deposited by electrochemical deposition, and wherein at least one of the first and second dielectric layers is removed from the edge of the wafer by etching prior to the electrochemical deposition.
17. The method of claim 1 , wherein the opening is a through semiconductor via (TSV).
18. The method of claim 1 , wherein said first portion and said second portion of said second conductive layer are adjoining.
19. The method of claim 1 wherein, after removing the second portion of the second conductive layer, the second conductive layer extends only over the surfaces of the opening.
20. The method of claim 1 , wherein said second portion of said second conductive layer extends to the edge of said opening.
21. A method for making a semiconductor device, comprising:
providing a semiconductor substrate having a layer stack disposed thereon which comprises a first electrically conductive layer sandwiched between first and second dielectric layers;
patterning the layer stack so as to form a first opening therein which exposes a portion of the substrate;
using the patterned layer stack as a first mask to etch the substrate, thus forming a second opening which includes the first opening and which extends into the substrate;
depositing a second electrically conductive layer such that the second conductive layer is in electrical contact with the first electrically conductive layer, wherein the second electrically conductive layer has a first portion that extends over the surfaces of the second opening and a second portion that extends over a portion of the mask adjacent to the second opening;
removing the second portion of the second conductive layer; and
depositing a first metal over the first portion of the second electrically conductive layer.
22. The method of claim 21 , wherein patterning the layer stack comprises:
depositing a layer of photoresist over the layer stack;
patterning the layer of photoresist so as to form a second mask having an opening therein which exposes a portion of the layer stack; and
using the second mask to pattern the layer stack.
23. The method of claim 21 , wherein using the second mask to pattern the layer stack involves etching the layer stack with a first etch, and wherein using the patterned layer stack as a first mask to etch the substrate involves etching the substrate with a second etch which is distinct from said first etch.
24. The method of claim 22 , wherein the first electrically conductive layer and the first and second dielectric layers are coextensive in the patterned layer stack.
25. The method of claim 21 , wherein the portion of the second opening which extends into the substrate is coextensive with the first opening.
26. The method of claim 22 , wherein the patterned layer of photoresist is removed after the layer stack is patterned but before the patterned layer stack is used as a first mask to etch the substrate.
27. The method of claim 21 , wherein the layer stack is formed by:
depositing a first dielectric material on the substrate, thereby forming the first dielectric layer;
depositing a first conductive material on the first dielectric layer, thereby forming the first electrically conductive layer; and
depositing a second dielectric material on the first electrically conductive layer, thereby forming the second dielectric layer.
28. The method of claim 27 , wherein the first electrically conductive layer is continuous.
29. The method of claim 27 , wherein the first electrically conductive layer is of uniform composition.
30. The method of claim 21 , wherein the second electrically conductive layer is in physical contact with the first electrically conductive layer, the first dielectric layer and the second dielectric layer.
31. The method of claim 21 , wherein the second electrically conductive layer is in physical contact with the edges of the first electrically conductive layer, the first dielectric layer and the second dielectric layer which are exposed by the first opening.
32. The method of claim 21 , wherein the second electrically conductive layer comprises a metal seed layer.
33. The method of claim 32 , further comprising forming a barrier layer having a first portion which extends over the surfaces of the second opening and a second portion which extends over a portion of the mask adjacent to the second opening, wherein the barrier layer is in electrical contact with the first electrically conductive layer, and wherein removing the second portion of the second conductive layer includes removing the second portion of the barrier layer.
34. The method of claim 21 , wherein removing the second portion of the second conductive layer exposes the second dielectric layer.
35. The method of claim 21 , wherein the first metal is deposited over the first portion of the second conductive layer after the second portion of the second conductive layer is removed but before the second dielectric layer is removed.
36. The method of claim 35 , wherein the second dielectric layer is removed after the first metal is deposited over the first portion of the second conductive layer.