Method of wafer processing with edge seed layer removal
A process of forming a conductive layer on a wafer is provided. A front surface and an edge surface of the wafer are coated with a seed layer. Further, the edge surface includes a back edge surface, a bevel surface and a front edge surface. During the process, the seed layer is removed from the back edge surface and the bevel surface using an etching process. Next, the conductive layer is formed by depositing a conductive material onto the remaining seed layer which coats the front edge surface and the front surface of the wafer. A part of the conductive layer which is on the front edge surface is then removed using another etching process.
1 . A method of forming a layer of a conductive material on a wafer, wherein a seed layer coats a front surface and an edge surface of the wafer, and wherein the edge surface includes a back edge surface, a bevel surface and a front edge surface, the method comprising the steps of:
removing the seed layer from the back edge surface and the bevel surface; and
forming the layer by depositing the conductive material onto the seed layer coating the front edge surface and the front surface of the wafer.
2 . The method of claim 1 , further comprising the step of removing at least a part of the layer which is on the front edge surface.
3 . The method of claim 1 , further comprising rotating the wafer during the step of removing the seed layer.
4 . The method of claim 3 , further comprising the step of applying a process solution onto the back edge surface of the wafer while it is rotated.
5 . The method of claim 1 , wherein the step of removing comprises chemical etching.
6 . The method of claim 1 , wherein the step of removing comprises electrochemical etching.
7 . The method of claim 2 , further comprising rotating the wafer prior to the step of removing the at least a part of the layer.
8 . The method of claim 7 , further comprising the step of applying a process solution to the at least a part of the layer while the wafer is rotated.
9 . The method of claim 8 , wherein the step of removing the at least a part of the layer comprises chemical etching.
10 . The method of claim 8 , wherein the step of removing the at least a part of the layer comprises electrochemical etching.
11 . A method of selectively removing a seed layer from a wafer using a process solution, the seed layer coating a front surface and an edge surface of the wafer, wherein the edge surface includes a back edge surface, a bevel surface and a front edge surface, comprising the steps of:
rotating the wafer; and
applying the process solution to the back edge surface so as to remove the seed layer from the back edge surface and the bevel surface by wrapping the process solution around the back edge surface and the bevel surface.
12 . The method of claim 11 , wherein a potential difference is applied between the seed layer and an electrode contacting the process solution during the step of applying the process solution.
13 . The method of claim 11 , wherein the step of rotating comprises rotating the wafer at a first predetermined rpm value to prevent the process solution from flowing to the front surface.
14 . The method of claim 13 , wherein rotating the wafer at the first predetermined rpm value wraps the process solution around the back surface edge and the bevel surface.
15 . The method of claim 11 , wherein the step of rotating comprises rotating the wafer at a second predetermined rpm value, wherein the second predetermined rpm value wraps the process solution around the back edge surface, the bevel surface and a part of the front edge surface.
16 . A method of forming a layer of a conductive material on a wafer comprising a front surface, a back surface and an edge surface, the edge surface including a back edge surface, a bevel surface and a front edge surface, the method comprising the steps of:
depositing a seed layer on the front surface and the edge surface of the wafer;
removing the seed layer from the back edge surface and the bevel surface; and
forming the layer by depositing the conductive material onto the seed layer coating the front edge surface and the front surface.
17 . The method of claim 16 , further comprising the step of removing a portion of the layer, which is on the front edge surface.
18 . The method of claim 16 , further comprising rotating the wafer during the step of removing the seed layer.
19 . The method of claim 18 , further comprising the step of applying a process solution to the back edge surface while the wafer is rotated.
20 . The method of claim 16 , wherein the step of removing comprises electrochemical removing.
21 . The method of claim 16 , wherein the step of removing comprises chemical removing.
22 . A method of forming a layer of a conductive material on a wafer using a deposition solution, wherein a seed layer coats a front surface and an edge surface of the wafer, and wherein the edge surface includes a back edge surface, a bevel surface and a front edge surface, the method comprising the steps of:
removing the seed layer from the back edge surface, the bevel surface and a part of the front edge surface;
establishing an electrical contact with a remaining part of the seed layer at the front edge surface; and
forming the layer by electrodepositing the conductive material onto the seed layer on the remaining part of the front edge surface and the front surface.
23 . The method of claim 22 , further comprising the step of applying a potential difference between the seed layer and an electrode contacting the deposition solution subsequent to the step of establishing the electrical contact.
24 . The method of claim 23 , further comprising the step of removing a portion of the layer, which is on the remaining part of the front edge surface.