Multistage extreme ultra-violet mask qualification

摘要

A technique for inspecting, qualifying and repairing photo-masks for use at extreme ultra-violet (EUV) wavelengths is described. In this technique, multiple images of a substrate and/or a blank that includes multiple layers deposited on the substrate are measured and compared to identify first potential defects. Using information associated with the first potential defects, such as locations of the first potential defects, another image of the EUV photo-mask that includes a mask pattern defined in an absorption layer, which is deposited on top of the multiple layers, is measured. Based on the other image and the first potential defects, second potential defects in the EUV photo-mask are identified. Next, a qualification condition of the EUV photo-mask is determined based on the first potential defects and the second potential defects.

主权项

1. A computer-implemented method for determining a qualification condition of an extreme ultra-violet (EUV) photo-mask, comprising:
measuring a first image of a substrate and a second image of a blank that includes multiple layers deposited on the substrate; identifying first potential defects on the substrate, in the multiple layers or both based on the first image and the second image; measuring a third image of the EUV photo-mask that includes a mask pattern defined in an absorption layer, which is deposited on top of the multiple layers, wherein measurement of the third image uses information associated with the first potential defects; identifying second potential defects in the EUV photo-mask based on the third image and the first potential defects; and determining the qualification condition of the EUV photo-mask based on the first potential defects and the second potential defects.