Drift measuring method, charged particle beam writing method, and charged particle beam writing apparatus
AssigneeNuFlare Technology, Inc.
InventorsShunji Shinkawa, Kouji Fukushima
Life of this patent
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Abstract
A detector 32 measures the value of the current formed by reflected electrons generated as a result of irradiation of a reference mark on a substrate with an electron beam 54, where the reference mark is made of a material having a different reflectance than the substrate. The signal from the detector 32 is amplified by a detecting unit 33 and converted to a digital signal by an A/D conversion unit 34. A control computer 19 then performs averaging processing on the digital signal which is then used for drift compensation by a writing data correcting unit 31.
Claims14
A method of measuring drift of a charged particle beam, comprising:
- individually irradiating a plurality of positions in the area on and around a reference mark with the charged particle beam, wherein the positions include either a surface of a substrate contiguously adjacent to the reference mark;
- or a surface of the substrate and a part of the reference mark formed on the substrate, wherein the reference mark is made of a material having a different reflectance than that of the substrate;
- measuring a value of a current formed by reflected charged particles generated as a result of the irradiation;
- and
- measuring the drift of the charged particle beam based on an amount of change in the current value, and
- wherein said individually irradiated positions are spatially separated from each other by positions that are not irradiated by the charged particle beam.
A method of writing with a charged particle beam, comprising:
- individually irradiating a plurality of positions in an area on and around a reference mark with the charged particle beam, wherein the positions include either a surface of a substrate contiguously adjacent to the reference mark or a surface of the substrate and a part of the reference mark formed on the substrate, wherein the reference mark is made of a material having a different reflectance than that of the substrate;
- measuring a value of a current formed by reflected charged particles generated as a result of the irradiation;
- and
- determining an amount of change in the position of the charged particle beam due to drift of the charged particle beam based on an amount of change in the current value and correcting an impinging position of the charged particle beam accordingly, and
- wherein said individually irradiated positions are spatially separated from each other by positions that are not irradiated by the charged particle beam.
A charged particle beam writing apparatus comprising:
- a reference mark on a substrate provided in a writing chamber in which a workpiece is placed, said reference mark being of a material having a different reflectance than said substrate;
- a detector configured to measure a value of a current formed by reflected charged particles generated as a result of irradiation of said reference mark with a charged particle beam;
- a correcting unit configured to perform drift compensation based on a signal from said detector;
- and
- a control computer configured to control irradiation of the charged particle beam to individually irradiate a plurality of positions in an area on and around the reference mark,
- wherein the positions include either a surface of a substrate contiguously adjacent to the reference mark or a surface of the substrate and a part of the reference mark formed on the substrate;
- and
- said correcting unit calculates an amount of change in the position of said charged particle beam due to drift of said charged particle beam and corrects an impinging position of said charged particle beam accordingly, and
- wherein said individually irradiated positions are spatially separated from each other by positions that are not irradiated by the charged particle beam.
Dependencies are inferred from the claim text.