The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 06, 2000
Filed:
May. 18, 1998
Teruaki Okino, Kamakura, JP;
Shohei Suzuki, Tokyo, JP;
Nikon Corporation, Tokyo, JP;
Abstract
Methods are disclosed for improving the accuracy of pattern registration between various layers formed on a sensitive substrate by microlithography using a charged-particle beam, especially registration accuracy as affected by rotation of image portions relative to corresponding image portions in an earlier applied layer. Errors in rotational angle of a pattern transferred to the n.sup.th layer and the arrangement direction of the transferred pattern on the substrate are measured. During projection of the (n+m).sup.th (e.g., the (n+1).sup.th) layer, the rotational angle of images that have passed through the mask subfields is corrected according to the measured rotational angle. Also, the deflection direction of the images on the substrate that have passed through the mask subfields is corrected according to the measured arrangement direction. The transfer subfields in the (n+m).sup.th layer can be accurately stitched together and corresponding transferred pattern in the n.sup.th and (n+m).sup.th layer can be accurately registered with respect to each other.