Wafer bevel polymer removal
A method of forming a semiconductor device is provided. A wafer with a dielectric layer disposed under a photoresist mask is placed in an etch chamber. The dielectric layer is etched. The wafer is raised. A cleaning gas is provided. A plasma is formed from the cleaning gas. A polymer that has formed on the bevel of the wafer is removed using the plasma from the cleaning gas. The wafer is removed from the etch chamber.
1. A method for forming a semiconductor device, comprising:
placing a wafer with a dielectric layer disposed under a photoresist mask in an etch chamber;
etching the dielectric layer, thereby forming polymer on the bevel of the wafer;
providing a stripping gas;
forming a plasma from the stripping gas;
stripping the photoresist mask using the plasma from the stripping gas;
quenching the plasma from the stripping gas;
raising the wafer;
providing a cleaning gas after quenching the plasma and raising the wafer;
forming a plasma from the cleaning gas;
removing the polymer that has formed on the bevel of the wafer using the plasma from the cleaning gas on the raised wafer; and
removing the wafer from the etch chamber, wherein the etching of the dielectric layer takes place within the etch chamber and wherein the removing of the polymer takes place within the etch chamber.
2. The method, as recited in claim 1 , further comprising stripping the photoresist mask in situ before raising the wafer.
3. The method, as recited in claim 2 , wherein the wafer has a back side and a front side, wherein the forming a plasma from the cleaning gas generates plasma adjacent to both the back side and front side of the wafer.
4. The method, as recited in claim 3 , wherein the raising the wafer uses lifting pins to raise the wafer.
5. The method, as recited in claim 4 , wherein the lifting pins have an electrical resistance greater than 100 ohms.
6. The method, as recited in claim 5 , wherein the raising the wafer raises the wafer 3 to 20 mm above a wafer support.
7. The method, as recited in claim 6 , wherein the lifting pins are resistant to etching.
8. The method, as recited in claim 7 , wherein a bias power is less than 300 watts is supplied during the removing polymer that has formed on the bevel.
9. The method, as recited in claim 8 , wherein the cleaning gas is at least 5% oxygen.
10. The method, as recited in claim 8 , wherein the cleaning gas consist essentially of oxygen.
11. The method, as recited in claim 1 , wherein the wafer has a back side and a front side, wherein the forming the plasma from the cleaning gas generates plasma adjacent to both the back side and front side of the wafer.
12. The method, as recited in claim 1 , wherein the raising the wafer uses lifting pins to raise the wafer.
13. The method, as recited in claim 12 , wherein the lifting pins have an electrical resistance greater than 100 ohms.
14. The method, as recited in claim 12 , wherein the lifting pins are resistant to etching.
15. The method, as recited in claim 1 , wherein the raising the wafer raises the wafer 3 to 20 mm above a wafer support.
16. The method, as recited in claim 1 , wherein a bias power is less than 300 watts is supplied during the removing polymer that has formed on the bevel.
17. The method, as recited in claim 1 , wherein the cleaning gas is at least 5% oxygen.
18. The method, as recited in claim 1 , wherein the cleaning gas consists essentially of oxygen.
19. The method, as recited in claim 1 , wherein the raising operation is performed after the quenching operation.
20. The method, as recited in claim 1 , wherein:
the raising of the wafer includes raising the wafer to a removal height;
the removing of the polymer is performed at least partly while the wafer is at the removal height; and
the removing of the wafer from the etch chamber is performed such that the wafer exits the etch chamber substantially at the removal height.