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US 2006/0051964 A1Published application
Method and system for etching a film stack
AssigneesTokyo Electron Limited, International Business Machines Corporation
InventorsAnnie Xia, Hiromasa Mochiki, Arpan Mahorowala
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Abstract
A method and system is described for preparing a film stack, and forming a feature in the film stack using a plurality of dry etching processes. The feature formed in the film stack can include a gate structure having a critical dimension of approximately 25 nm or less. This critical dimension can be formed in the polysilicon layer using four mask layers.
Claims28
A method of preparing a feature on a substrate comprising:
- forming a film stack on a substrate, said film stack comprising a polysilicon layer, a first mask layer formed on said polysilicon layer, a second mask layer formed on said first mask layer, a third mask layer formed on said second mask layer, a fourth mask layer formed on said third mask layer, and a layer of light-sensitive material formed on said fourth mask layer;
- forming a pattern having a first critical dimension in said layer of light sensitive material using lithography;
- trimming said pattern to form a second critical dimension in said pattern less than said first critical dimension;
- transferring said pattern to said fourth mask layer;
- transferring said pattern to said third mask layer;
- transferring said pattern to said second mask layer;
- transferring said pattern to said first mask layer;
- and
- transferring said pattern to said polysilicon layer, wherein a final critical dimension of approximately 25 nm or less is achieved.
6 more elements
Dependencies are inferred from the claim text.