Method for controlling exposure region in bevel etching process for semiconductor fabrication

1. A plasma processing apparatus, comprising:

a lower sheltering module;

an upper sheltering module arranged adjacent to the lower sheltering module and comprising:

an upper plate; and

an upper PEZ ring positioned around the upper plate;

a shadowing unit detachably positioned in a recess of the upper PEZ ring; and

a plasma generation module configured to generate plasma in a peripheral region of the lower sheltering module and the upper sheltering module, comprising:

a lower electrode unit disposed adjacent to the lower sheltering module; and

an upper electrode unit disposed adjacent to the upper sheltering module.

2. The plasma processing apparatus as claimed in claim 1 , wherein the upper PEZ ring has a base portion and a connecting portion downwardly projected from the base portion, and the shadowing unit is positioned on the connecting portion.

3. The plasma processing apparatus as claimed in claim 2 , wherein the connecting portion has a bottom surface for defining an upper plasma exclusion zone for protecting the wafer from being exposed to plasma and a connecting surface immediately connected to the bottom surface, wherein the shadowing unit is positioned on the connecting surface.

4. The plasma processing apparatus as claimed in claim 3 , wherein the bottom surface of the connecting portion is flush with a bottom surface of the shadowing unit for defining the upper plasma exclusion zone.

5. The plasma processing apparatus as claimed in claim 1 , wherein the outer width of the shadowing unit across the upper sheltering module is smaller than the diameter of the wafer.

6. The plasma processing apparatus as claimed in claim 1 , wherein the shadowing unit comprises two engaging parts each having an arc angle of about 180 degrees and circumferentially positioned on the upper PEZ ring.

7. The plasma processing apparatus as claimed in claim 1 , wherein the upper PEZ ring and the shadowing unit are made of the same material selected from a group comprising quartz, Al 2 O 3 , Si 3 N 4 , AIN, Y 2 O 3 and TiO 2.

8. The plasma processing apparatus as claimed in claim 1 , wherein the upper PEZ ring and the shadowing unit are coated with an anti-corrosion material.

9. A plasma processing apparatus, comprising:

a lower sheltering module;

an upper sheltering module arranged adjacent to the lower sheltering module and comprising an upper PEZ ring having a base portion and a connecting portion downwardly projected from the base portion, wherein a recess is formed on the connecting portion, and a lower wall of the recess is distant from a bottom surface of the connecting portion, and a groove is formed on the lower wall of the recess; and

a plasma generation module configured to generate plasma in the peripheral region of the lower sheltering module and the upper sheltering module, comprising:

a lower electrode unit disposed adjacent to the lower sheltering module; and

an upper electrode unit disposed adjacent to the upper sheltering module.

10. The plasma processing apparatus as claimed in claim 9 , further comprising a shadowing unit positioned at the connecting portion, wherein the shadowing unit comprises:

a longitudinal portion extending parallel to the connecting portion; and

an engaging portion connected to the longitudinal portion and positioned in the recess.

11. The plasma processing apparatus as claimed in claim 10 , wherein the bottom surface of the connecting portion is flush with the bottom surface of the shadowing unit.

12. The plasma processing apparatus as claimed in claim 10 , wherein the shadowing unit comprises two arc-shaped parts circumferentially positioned on the upper PEZ ring.

13. The plasma processing apparatus as claimed in claim 10 , wherein a portion of the engaging portion is positioned in the groove.

14. The plasma processing apparatus as claimed in claim 10 , wherein the upper PEZ ring and the shadowing unit are made of the same material selected from a group comprising quartz, Al 2 O 3 , Si 3 N 4 , AIN, Y 2 O 3 and TiO 2.

15. The plasma processing apparatus as claimed in claim 10 , wherein the upper PEZ ring and the shadowing unit are coated with an anti-corrosion material.

16. The plasma processing apparatus as claimed in claim 9 , wherein the recess continuously surrounds the connecting portion.

17. The plasma processing apparatus as claimed in claim 9 , wherein the recess has a rectangular or triangular cross section.

18. A plasma processing apparatus, comprising:

a lower sheltering module;

an upper sheltering module arranged adjacent to the lower sheltering module and comprising an upper PEZ ring having a base portion and a connecting portion downwardly projected from the base portion, wherein a recess is formed on and continuously surrounds the connecting portion;

a shadowing unit positioned at the connecting portion, wherein the shadowing unit comprises:

a longitudinal portion extending parallel to the connecting portion; and

an engaging portion connected to the longitudinal portion and positioned in the recess; and

a plasma generation module configured to generate plasma in the peripheral region of the lower sheltering module and the upper sheltering module, comprising:

a lower electrode unit disposed adjacent to the lower sheltering module; and

an upper electrode unit disposed adjacent to the upper sheltering module.

19. The plasma processing apparatus as claimed in claim 18 , wherein the shadowing unit is detachably positioned on the upper PEZ ring.

20. The plasma processing apparatus as claimed in claim 18 , wherein the recess continuously surrounds the connecting portion.