Title:
METHOD OF EXPOSURE
Document Type and Number:
Japanese Patent JP3218475
Kind Code:
B2
Abstract:
PURPOSE: To realize measurement and correction only with a reticle used for exposure by measuring focal points before and after the exchange of reticle, for each reticle, to obtain a difference between two measurements, which is considered to be caused by the reticle itself and excluded from being employed in correction.
CONSTITUTION: A printing trial with reticle A is carried out to obtain an optimal focal position Z0. In a focus signal detection system 20, focus measurement (FC) is carried out with the same reticle A to obtain a focal position (a). Here, (Z0-a) is defined as an offset value for the focus measurement with the reticle A. An exposure step at the position Z0 is carried out with the reticle A, and the exposure is completed. Then, just before the change of the reticle A, the focus measurement is carried out again to obtain a focal position (a1). Even when a focal position (b) is obtained from the focus measurement just after the change from the reticle A to the reticle B, the exposure step with the reticle B is carried out by using the optimal focal position [Z0+(a1-a)], which is obtained just before the change of the reticle A.
Inventors:
Masahiro Nei
Application Number:
JP31776491A
Publication Date:
October 15, 2001
Filing Date:
December 02, 1991
Export Citation:
Assignee:
NIKON CORPORATION
International Classes:
G03F7/20; G03F9/00; H01L21/027; H01L21/30; (IPC1-7): H01L21/027; G03F7/20
Domestic Patent References:
| JP61181127A | ||||
| JP458250A | ||||
| JP480761A |