Intel Corporation

Dai Nippon Printing Co., Ltd.

Tsukasa Abe

Toshifumi Yokoyama

Yoshihiro Tezuka

Han-Ming Wu

Albert Kwok

Y Long He

Masami Nara

The invention provides methods and apparatuses for controlling critical dimension (CD) uniformity of a photomask by neutralizing CD variation associated with pattern density and process fluctuation.

Method and apparatus for photomask fabrication

Plasma etching is controlled utilizing two etchant gases to form a plasma so as to obtain controlled (e.g., uniform) etch rate across a wafer. One etchant gas forms a positive plasma, which is the dominant plasma. The other etchant gas forms a negative plasma, which is the secondary plasma. The ratio of dominant plasma to the secondary plasma can be adjusted such that ion densities are uniform across the wafer, resulting in uniform etch rate over the wafer.

Plasma etching uniformity control

A method for repairing a photomask by removing a residual defect in the photomask is provided which can solve problems, involved in repair of the photomask by the conventional laser beam irradiation, such as various types of maladjustments, limitation of focusing of a laser beam, creation of roughening in the repaired area, and problems, involved in repair of the photomask by focused ion beam irradiation, such as damage to a transparent substrate and a gallium stain. The method comprises the steps of: (a) applying actinic radiation to the residual defect area to remove the residual defect except for a defect edge region having a predetermined width from the periphery of the residual defect area over the whole periphery of the residual defect area; and (b) removing the defect edge region, remaining unremoved by the physical means, having a predetermined width from the periphery of the residual defect area over the whole periphery of the residual defect area by chemical etching with a chemical, the predetermined width being such that the influence of the actinic radiation does not extend over the outside of the residual defect area and, at the same time, the etching time can be set so that the region having a predetermined width from the periphery is removed by the chemical etching without any substantial influence on other layers including a light-shielding layer.

Method for repairing photomask by removing residual defect in said

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Santa Clara, CA, United States of America

Tsukasa Abe