Adaptive lithographic critical dimension enhancement

Abstract

A system, apparatus, and method for improving CD uniformity in lithographic system is presented herein. The system includes an exposure apparatus configured to expose substrates, a track apparatus that is operatively coupled to the exposure apparatus and a plurality of processing modules and apparatus. The system also includes a measuring device configured to measure attributes of the exposed and processed substrates and to assess whether the exposed and processed substrate attributes are uniform based on pre-specified substrate profile information. The system further includes a module configured to adaptively calculate corrective exposure data based on the measured attributes upon determining that said attributes are not uniform. The corrective exposure data is configured to correct for non-uniformities in the substrates by regulating the exposure dosage of the exposure apparatus. Once the substrates are assessed to achieve the desired uniformity, the substrates are exposed by the exposure apparatus in accordance with the corrective exposure data, the uniformity of the exposed substrate continues to be monitored and the dose corrections are updated as required to maintain uniformity.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention generally relates to lithographic systems and methods of lithographic exposure. [0003] 2. Description of the Related Art [0004] The term “patterning means” as will be employed herein should be broadly interpreted to refer to means that can be used to endow an incoming radiation beam with a patterned cross-section, corresponding to a pattern that is to be created in a target portion of the substrate. The term “light valve” may also be used in this context. Generally, the pattern will correspond to a particular functional layer in a device being created in the target portion, such as an integrated circuit or other device (see below). Examples of such patterning means include: [0005] (a) a mask: the concept of a mask is well known in lithography, and it includes mask types such as binary, alternating phase-shift, and attenuated phase-shift, as well as various hybrid mask types. Placement of such a...

AI Technical Summary

Benefits of technology

The present invention provides a system and method for improving the uniformity of CDs (critical dimensions) in a lithographic system that uses an exposure apparatus and a track apparatus. The system measures the attributes of substrates processed by the lithographic system and assesses whether the CDs are uniform based on pre-specified criteria. If the CDs are not uniform, corrective exposure data is adaptively calculated to correct non-uniformities in the substrates by regulating the exposure dosage in the exposure apparatus. The substrates are then exposed by the exposure apparatus in accordance with the corrective exposure data. The technical effect of the invention is to improve the accuracy and reliability of the lithographic process by ensuring uniformity of CDs in the substrates.

Problems solved by technology

There are, however, numerous activities during the lithographic fabrication process that affect the critical dimension uniformity (CDU) and compromise the quality of the exposed pattern.

Such variations may occur across a target field, across a wafer, and between wafers and ultimately result in loss of yield.

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