ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
We have studied the imaging characteristics of an excimer laser stepper as a function of laser wavelength. Focus, magnification, distortion, CD process window, and laser performance were all examined, and an operating wavelength was selected. The self-metrology capabilities of both the laser and stepper were tested to insure that the system would set itself to the correct wavelength upon initialization, and maintain that setting during volume production activity. The use of an on-line stepper image sensor to evaluate the quality of the aerial image, coupled with the built-in wavelength tracking system as part of the laser optics, was found to provide the required closed loop system for wavelength and focus control. Based on these experiments, we have determined that a quick aerial image check before each production lot should suffice to insure focus control of better than 0.25 microns and magnification errors less than 15 nm during the entire time required to expose the lot.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760322107
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