Radiation imagery chemistry: process – composition – or product th – Including control feature responsive to a test or measurement
Reexamination Certificate
2001-01-24
2001-09-04
Young, Christopher G. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Including control feature responsive to a test or measurement
Reexamination Certificate
active
06284419
ABSTRACT:
TECHNICAL FIELD
The present invention relates to methods of reducing proximity effects in lithographic processes.
BACKGROUND OF THE INVENTION
Fabrication of integrated circuitry typically involves lithographically transferring a pattern which is disposed on a mask onto a layer of material such as photoresist received over a substrate. The pattern on the mask generally defines integrated circuitry patterns and alignment patterns. It has been observed that differences in pattern development of circuit features can depend upon the proximity of the features relative to one another. So-called “proximity effects” in a lithographic process can arise during imaging, resist pattern formation, and subsequent pattern transfer steps such as etching. The magnitude of the proximity effects depends on the proximity or closeness of the two features present on the masking pattern. Proximity effects are known to result from optical diffraction in the projection system used to form the pattern over the substrate. This diffraction causes adjacent features to interact with one another in such a way as to produce pattern-dependent variations. These variations can affect the integrity of the finished devices.
This invention arose out of concerns associated with improving the manner in which integrated circuitry is formed. In particular, this, invention arose out of concerns associated with reducing proximity effects.
SUMMARY OF THE INVENTION
Methods of reducing proximity effects in lithographic processes wherein an integrated circuitry pattern is transferred from a mask onto a semiconductor substrate are described. In one embodiment, a desired spacing is defined between a main feature which is to reside on a mask and which is to be transferred onto the substrate, and an adjacent proximity effects-correcting feature. After the spacing definition, the dimensions of the main feature are adjusted relative to the proximity effects-correcting feature to achieve a desired transferred main feature dimension. In another embodiment, a desired spacing is defined between a main feature having an edge and an adjacent sub-resolution feature. The edge of the main feature is moved relative to the sub-resolution feature to achieve a desired transferred main feature dimension.
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Baggenstoss William
Burdorf James E.
Pierrat Christophe
Stanton William
Micro)n Technology, Inc.
Wells, St. John, Roberts, Gregory & Matkins P.S.
Young Christopher G.
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