Image-height offset in TTL on-axis alignment method

Noriaki Ishio; Keiji Fujiwara; Hitoshi Nagata

doi:10.1117/12.20219

1 June 1990 Image-height offset in TTL on-axis alignment method

Noriaki Ishio, Keiji Fujiwara, Hitoshi Nagata

Proceedings Volume 1264, Optical/Laser Microlithography III; (1990) https://doi.org/10.1117/12.20219
Event: Microlithography '90, 1990, San Jose, CA, United States

Abstract

The problems of the offset errors in the TTL alignment are studied. The further the position of alignment optics is from the center of the projection lens the bigger the offset error becomes. The lmageheight offset is the offset error caused by the position of alignment optics on the imaged field of projection lens. The maximum values of lmage. height offset for the dark and bright field alignment modes are O. 3p. m and O. O8tm respectively. The lmageheight offset is large with the dark field alignment because the stopper (spatial filter) in the optics is not fixed at the best place. 1 Recently the resolution of reduction projection photolithography has been improved to linewidth accuracy of 0. 5 pm. The required overlay accuracy is generally one fourth or one fifth of the pattern width thus a registration of the order of tens of nanometers is required for submicron devices fabrication. The overlay errors are divided into the intra4ield matching error and the registration error. The intra-field matching error consists of the difference in lens distortions between several steppers. If only one stepper is used to fabricate the device the overlay accuracy is almost equal to the registration accuracy. Many alignment methods have been developed in order to achieve a fine registration accuracy. Recently the g-line stepper has used two typical alignment methods. One is the TTL on axis alignment method

Citation Download Citation

Noriaki Ishio, Keiji Fujiwara, and Hitoshi Nagata "Image-height offset in TTL on-axis alignment method", Proc. SPIE 1264, Optical/Laser Microlithography III, (1 June 1990); https://doi.org/10.1117/12.20219

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