David S Ferranti

US Patent:

20010027917, Oct 11, 2001

Filed:

Mar 9, 2001

Appl. No.:

09/802342

Inventors:

David Ferranti - Concord MA, US
Sharon Szelag - Lynnfield MA, US
J. Casey - West Roxbury MA, US

International Classification:

C23C014/32
G11B005/74
C23C014/00
G11B023/00

US Classification:

204/192110, 204/192320, 204/298040, 204/298360, 250/492210, 360/131000

Abstract:

A method of repairing opaque defects in lithography masks entails focused ion beam milling in at least two steps. The first step uses a large pixel spacing to form multiple holes in the defect material, with the milled area extending short of the defect material edge. The final step uses a pixel spacing sufficiently close to produce a smooth floor on the milled area, and extends to the edge of the defect. During the second step, an etch enhancing gas such as bromine is preferably used.

US Patent:

20040121069, Jun 24, 2004

Filed:

Aug 7, 2003

Appl. No.:

10/636309

Inventors:

David Ferranti - Concord MA, US
Valery Ray - Haverhill MA, US
Gerald Smith - Nashua NH, US
Christian Musil - New Providence NJ, US

International Classification:

C23C014/28

US Classification:

427/140000, 427/595000, 118/715000

Abstract:

Topographical data from a scanning probe microscope or similar device is used as a substitute for endpoint detection to allow accurate repair of defects in phase shift photomasks using a charged particle beam system. The topographical data from a defect area is used to create a display of a semitransparent topographical map, which can be superimposed over a charged particle beam image. The density of the topographical image and the alignment of the two images can be adjusted by the operator in order to accurately position the beam. Topographical data from an SPM can also be used to adjust charged particle beam dose for each point within the defect area based upon the elevation and surface angle at the particular point.