US 7,397,941 B1 · Method and apparatus for electron beam inspection of repeated patterns

Abstract

One embodiment disclosed relates to a method of detecting defects in a microminiature pattern repeated over a particular surface of an object. The method includes providing an image detector capable of resolving intensity data for each pixel of an array of m×n pixels of an image projected thereupon. An area of the surface of the object is illuminated with incident electrons, radiation from the illuminated area is detected, and image data from the detected radiation is retrieved into a data processor. If necessary, the image data is rotated for alignment purposes. The scale of the image data is then adjusted such that a dimension of a cell of the repeated pattern in the image data is equivalent to a distance across an integer number of pixels of the m×n pixel array. With the scale adjusted, then features in one cell of the repeated pattern are compared with features in another cell of the repeated pattern to detect said defects.

Claims5

Dependent claims

A method of detecting defects in a microminiature pattern repeated over a particular surface of an object, the method comprising:

illuminating a surface of the object with incident electrons;
deflecting image electrons mirrored from the surface and the incident electrons in opposite directions using a beam separator;
detecting the image electrons from the surface in parallel using a pixel array electron detector capable of resolving intensity data for each pixel of an image projected thereupon;
retrieving image data from the detected image electrons from the surface into a data processor;
determining a sub-pixel difference between a cell dimension in a first portion of the surface and a nearest integer number of pixels;
determining sub-pixel differences between a cell dimension in other portions of the surface and a nearest integer number of pixels;
selecting one of the other portions having a sub-pixel difference which is close to the sub-pixel difference in the first portion;
and
comparing features in the first portion with features in said selected portion to detect said defects.

6 more elements

Dependencies are inferred from the claim text.

Method and apparatus for electron beam inspection of repeated patterns

Life of this patent

Method and apparatus for electron beam inspection of repeated patterns

Life of this patent

Abstract

Claims5