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A methodology to place secondary printed features to enhance printability of a primary feature.

IP.com Disclosure Number: IPCOM000235794D
Publication Date: 2014-Mar-25
Document File: 3 page(s) / 96K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for the insertion of secondary printed features on a wafer in order to improve the optical environment around a primary printed structure.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 51% of the total text.

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A methodology to place secondary printed features to enhance printability of a primary feature.

Currently, the sources are optimized with the densest pitches in mind. This leaves the ISO features with a poor process window (PW). In order to enhance the PW of the isolated features, Sub Resolution Assist Features (SRAFs) are used. The use of SRAFs placement has several shortcomings. The SRAFs are complex to place and increase the runtime of the Optical Proximity Correction (OPC). The development time to determine placement is extensive. Even with placement, the effectiveness of the SRAFs is not always guaranteed for every design construct.

The novel approach is to add printing secondary features (PSFs). These are not necessarily assist features because the PSFs may be of comparable or even larger size than the feature being assisted in printing. The method for the insertion of secondary printed features on the wafer in order to improve the optical environment around a primary printed structure comprises the following components and process steps:

1. Locate structures in the level above and below the level of interest on the stack 2. Based upon the electrical and physical interaction of the level of interest, the level above and below, determine which areas in the layout on the level of interest can have extraneous printed features that will not affect the intended characteristics of the chip 3. Add assist features to the layout in the industry-accepted manner; however, areas identified to allow secondary prin...