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Method for improved patterning fidelity of lithographically patterned contacts

IP.com Disclosure Number: IPCOM000085000D
Publication Date: 2005-Mar-02
Document File: 3 page(s) / 59K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for improved patterning fidelity of lithographically patterned contacts. Benefits include improved functionality and improved performance.

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Method for improved patterning fidelity of lithographically patterned contacts

Disclosed is a method for improved patterning fidelity of lithographically patterned contacts. Benefits include improved functionality and improved performance.

Background

              When patterning contacts, the density of the contacts within a given region can affect the final pattern. The conventional solution balances the risk of bridging close-proximity contacts while maintaining a minimum surface area on the more sparely distributed contact.

              Close proximity squares have a tendency to tear-drop where the contour on the close proximity side interacts significantly with the adjacent polygons and is pulled towards the neighboring contour. The hole size is reduced and an elongated (rather than circular) pattern is produced. The red line and the red circle highlight the “tear drop” effect in the illustration (see Figure 1).

              Conventional dissection and recipe parameter setting techniques only take into account the length of a given edge and the angles and lengths of adjacent edges when determining values. Proximity effects are not considered. Models of the layer fabrication process are relied on to predict what the final pattern will be on the wafer.  The edges are then moved to arrive at the desired predicted intensity at the drawn edge. If a given edge is not broken into enough segment, then the edge can not adjust enough to reach the desired predicted intensity. However, the size of the output stream file is directly correlated to the number of segments a given edge is divided into. The current division strategy does not always provide enough flexibility for a given edge due to a global approach to rules for dissecting the edge.

General description

      The disclosed method improves the patterning fidelity of lithographically patterned contacts by reducing the bridging risk in dense regions while maintaining desired shape in spare regions.

The method includes a polygon shape and its proximity to another polygon when determining the solution for a given edge. It is classified into a tight proximity edge or a relaxed proximity edge. Based on its classification, a specialized solution includes dissection, evaluation point placement, and growth/contraction properties....