Electrostatic chuck assembly and charged particle beam device

Abstract

This invention discloses an electrostatic chuck assembly and a charged particle beam device. The electrostatic chuck assembly includes: an electrostatic chuck for carrying a wafer; and an annular electrode disposed around the electrostatic chuck. The apex of the annular electrode is higher than the upper surface of the wafer placed on the electrostatic chuck. By setting the apex height of the annular electrode higher than the upper surface of the wafer, this invention makes the equipotential line between the wafer edge and the annular electrode smoother, improving the uniformity of the electric field distribution at the wafer edge, thereby enhancing the imaging quality and resolution of the charged particle beam device.

Claims

1. An electrostatic chuck assembly, comprising: An electrostatic chuck for carrying a wafer; a ring electrode disposed around the electrostatic chuck; the apex of the ring electrode is higher than the upper surface of the wafer placed on the electrostatic chuck.

2. The electrostatic chuck assembly as claimed in claim 1, wherein, The annular electrode is spaced from the edge of the wafer, and the height of the apex of the annular electrode above the upper surface of the wafer is given by a certain formula. The distance and height satisfy the following relationship.

3. The electrostatic chuck assembly as described in claim 2, wherein, The spacing refers to the distance between the inner edge of the annular electrode and the outer edge of the wafer when the annular electrode and the wafer are placed concentrically.

4. The electrostatic chuck assembly as claimed in claim 1, wherein, The ring electrode includes at least two first sub-electrodes stacked vertically, and the operating voltage applied to each first sub-electrode may be the same or different.

5. The electrostatic chuck assembly as claimed in claim 4, wherein, When the operating voltages applied to the first sub-electrodes are different, the voltage of the first sub-electrode located at the top in the vertical direction is greater than the voltage of the first sub-electrode located at the bottom in the vertical direction.

6. The electrostatic chuck assembly as claimed in claim 4, wherein, The first sub-electrode located at the top in the vertical direction has a first upper surface, and the first sub-electrode located at the bottom in the vertical direction has a second upper surface; the first upper surface is higher than the upper surface of the wafer placed on the electrostatic chuck, and the second upper surface is lower than the upper surface of the wafer placed on the electrostatic chuck.

7. The electrostatic chuck assembly as claimed in claim 1 or 4, wherein, The cross-sectional shape of the annular electrode along the vertical direction includes at least one of rectangular, L-shaped, T-shaped, stepped, and arc-shaped.

8. The electrostatic chuck assembly as claimed in claim 4, wherein, The cross-sectional shape of the annular electrode along the vertical direction is T-shaped or L-shaped, and the width of the first sub-electrode located at the top along the vertical direction is smaller than the width of the first sub-electrode located at the bottom along the vertical direction.

9. The electrostatic chuck assembly as claimed in claim 4, wherein, The cross-sectional shape of the ring electrode along the vertical direction is stepped, with the first sub-electrode at the top of the vertical direction having the smallest width and the first sub-electrode at the bottom of the vertical direction having the largest width.

10. The electrostatic chuck assembly as claimed in claim 1, wherein, The annular electrode is continuous and uninterrupted in the circumferential direction.

11. The electrostatic chuck assembly as claimed in claim 1, wherein, The annular electrode includes at least two mutually spaced second sub-electrodes distributed circumferentially along the electrostatic chuck, and the operating voltage applied to each second sub-electrode may be the same or different.

12. The electrostatic chuck assembly as claimed in claim 10 or 11, wherein, The cross-sectional shape of the annular electrode along the vertical direction includes at least one of rectangular, L-shaped, T-shaped, stepped, and arc-shaped.

13. The electrostatic chuck assembly as claimed in claim 11, wherein, The second sub-electrode is shaped as an arc segment distributed circumferentially along the electrostatic chuck.

14. The electrostatic chuck assembly as claimed in claim 1, wherein, The annular electrode has a straight chamfer or a rounded chamfer on the side adjacent to the edge of the wafer.

15. A charged particle beam device, comprising: The main chamber includes a wafer loading position and a wafer observation position; A sample stage, disposed within the main chamber and movable along a trajectory from the wafer loading position to the wafer observation position; an electrostatic chuck assembly as described in any one of claims 1 to 14, disposed on the sample stage; a particle beam irradiation device, located in the main chamber and above the wafer observation position; at least one voltage source connected to the annular electrode for providing an operating voltage; and a controller connected to the voltage source for controlling the magnitude of the operating voltage.

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