Abstract: A method and apparatus for measuring the dimensions of features on the surface of a semiconductor device. The method may include passing a first electron beam having a first depth of focus over the semiconductor device and passing a second electron beam having a second depth of focus over the device. Electrical signals generated by the two electron beams may be analyzed singly or in combination to determine the lateral or vertical dimensions of the features at one or more positions relative to the surface of the semiconductor device. In one embodiment, the first and second electron beams are generated sequentially from a single electron gun. In another embodiment, the first and second electron beams are generated sequentially or simultaneously by either two separate electron guns or a single electron gun positioned proximate to two separate electron beam ports.

Abstract: A pattern inspection apparatus and method that uses multiple images in a pattern recognition process used to detect defects in an object being inspected is disclosed. A user is provided with multiple image selection windows allowing the user to select multiple desired images from the object to form a pattern to be recognized within the object. The multiple desired images will be substantially free from undesired features of the object. Once the multiple desired images are selected, the spatial relationship between them is determined and used to learn the pattern to be recognized. The spatial relationship between the desired images further filters out undesired features. The pattern to be recognized is used in a subsequent pattern recognition analysis. Since the pattern to be recognized includes only desired images and their relationship, undesired features that could corrupt the pattern recognition analysis are not present during the analysis.

Abstract: A method and apparatus for measuring the dimensions of features on the surface of a semiconductor device. The method may include passing a first electron beam having a first depth of focus over the semiconductor device and passing a second electron beam having a second depth of focus over the device. Electrical signals generated by the two electron beams may be analyzed singly or in combination to determine the lateral or vertical dimensions of the features at one or more positions relative to the surface of the semiconductor device. In one embodiment, the first and second electron beams are generated sequentially from a single electron gun. In another embodiment, the first and second electron beams are generated sequentially or simultaneously by either two separate electron guns or a single electron gun positioned proximate to two separate electron beam ports.