Aperture patterns for defining multibeams

Abstract

Disclosed herein is an aperture array configured to define sub-beams that are scanned in a scan direction in a charged particle device, the aperture array including a plurality of apertures arranged in an aperture pattern including a plurality of parallel aperture rows, the apertures being arranged along the aperture rows and being inclined with respect to the scan direction, edge aperture rows that define edges of the aperture pattern, and adjacent aperture rows adjacent the edge rows, wherein the edge aperture rows and the adjacent aperture rows each include fewer apertures than other aperture rows of the aperture pattern.

Claims

1. In a charged particle apparatus, an aperture array that defines a subbeam scanned in the scanning direction, wherein the aperture array is A plurality of parallel aperture rows, wherein apertures are arranged along the aperture rows and the aperture rows are inclined with respect to the scanning direction, Edge aperture rows define the edges of the aperture pattern, The adjacent aperture row adjacent to the aforementioned edge row, Includes a plurality of apertures arranged in the aperture pattern, Each of the edge aperture row and the adjacent aperture row contains fewer apertures than another aperture row of the aperture pattern, the aperture pattern includes a central set of aperture rows between two side sets of aperture rows, one of the side sets of aperture rows includes the edge aperture row and the adjacent aperture row, and the distance between adjacent apertures along the aperture row of the central set in a direction orthogonal to the scanning direction is periodic and equidistant. An aperture array in which the distance between at least adjacent apertures along the aperture row of the sideset is not equal.

2. The aperture array according to claim 1, wherein one aperture row of the side set contains fewer apertures than the aperture row of the central set.

3. The aperture array according to claim 1 or 2, wherein when the aperture array is scanned against a target surface, the total number of apertures in each of the multiple aperture rows in the side set is equal to the number of apertures in the aperture row of the central set.

4. The aperture array according to any one of claims 1 to 3, wherein each of the aperture rows in one of the side sets has a corresponding aperture row in the other of the side sets, and the sum of the number of apertures in the aperture rows from one of the side sets and the corresponding aperture rows from the other of the side sets is the same as the number of apertures in one of the aperture rows of the central set.

5. The aperture array according to any one of claims 1 to 4, wherein the aperture row of the central set includes the same number of apertures.

6. The aperture array according to any one of claims 1 to 5, wherein one or both of the aperture rows of the side set adjacent to the central set are aperture rows of the corresponding side set having the maximum number of apertures in the corresponding side set.

7. The aperture array according to claim 6, wherein the remaining rows of the corresponding side set have the same number of apertures as, or fewer than, the adjacent aperture rows in the direction of the central set.

8. The aperture array according to any one of claims 1 to 7, wherein along the aperture row of the central set, there are 5 to 5000 apertures, such as 10 or 14.

9. The aperture array according to any one of claims 1 to 8, wherein 14 apertures exist along the aperture row of the central set, and one or both of the side sets include aperture rows having 10, 7, and 4 apertures, respectively.

10. The aperture array according to any one of claims 1 to 9, wherein the distance between adjacent apertures in two of the aperture rows is different.

11. The aperture array according to any one of claims 1 to 10, wherein the aperture pattern is located within a beam area, and the beam area is substantially circular or elliptical.

12. A charged particle apparatus comprising a charged particle source and an aperture array according to any one of claims 1 to 11, The source guides a charged particle beam toward the aperture array so that a multibeam is emitted from the aperture array. A charged particle apparatus in which the charged particle apparatus is arranged to scan a sample in a linear scanning direction with the multibeam.

13. The charged particle apparatus according to claim 12, wherein the charged particle apparatus is arranged to operate in a continuous scanning mode.

14. The charged particle apparatus according to claim 12 or 13, wherein the aperture array is located within the beam area of ​​the charged particle beam from the source.

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