0.25 m Periodic Structures For Lightwave Technology Fabricated By Spatial Frequency Doubling Lithography (SFDL)

T. E. Jewell; J. H. Bennewitz; V. Pol; R. Cirelli

doi:10.1117/12.953178

25 July 1989 0.25 μm Periodic Structures For Lightwave Technology Fabricated By Spatial Frequency Doubling Lithography (SFDL)

T. E. Jewell, J. H. Bennewitz, V. Pol, R. Cirelli

Author Affiliations +

Proceedings Volume 1088, Optical/Laser Microlithography II; (1989) https://doi.org/10.1117/12.953178
Event: 1989 Santa Clara Symposium on Microlithography, 1989, San Jose, CA, United States

Abstract

A new method to fabricate the gratings useful for integrated optical circuits (IOC) is described. The method combines optical projection lithography with spatial filtering. The projection lens uses nearly coherent illumination. Only the two first orders diffracted by the mask grating are allowed to pass through the lens. This produces a grating pattern in the image plane that has a high contrast (near 100%), a large depth of focus (approx. 13 μm), and a period half of what would have been obtained in normal imaging. Thus, with a 5X reduction lens a 5 μm period grating on the mask produces a 0.5 μm period image on the wafer. 0.5 μm period gratings are useful for fabrication of Bragg filters in dielectric film waveguides. Gratings of different periods, sizes, locations, orientations, and configurations (chirped, phase shifted, etc.) can all be produced on the same chip with a single exposure. Using a deep UV lens with a line-narrowed 248 nm KrF excimer laser for illumination, we printed 0.5 μm period gratings in an oxide layer on 10 mm X 10 mm silicon chips. Because of the high contrast, the photoresist patterns had very high quality. In addition, the extended depth of focus was observed. This method is primarily useful for patterning periodic structures. Lenses designed for this system could be made with large numerical apertures and/or image fields, and be able to pattern gratings of 0.23 μm period for semiconductor waveguide devices. This technique opens up the possibility of high-volume production of IOC chips with Bragg filters using standard IC fabrication facilities.

Citation Download Citation

T. E. Jewell, J. H. Bennewitz, V. Pol, and R. Cirelli "0.25 μm Periodic Structures For Lightwave Technology Fabricated By Spatial Frequency Doubling Lithography (SFDL)", Proc. SPIE 1088, Optical/Laser Microlithography II, (25 July 1989); https://doi.org/10.1117/12.953178

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available