Holding device, method of determining attraction abnormality in holding device, lithography apparatus, and method of manufacturing article
A holding device in a lithography apparatus for transferring a pattern formed on a mold to a substrate, for attracting/holding the mold or substrate by a reduced pressure, comprising: a holding unit holding the mold or substrate, having concave portions forming spaces together with the mold or substrate; a first pressure mechanism to depressurize at least one first space among the spaces formed by the mold or substrate and the holding unit; a second pressure mechanism setting at least one second space among the spaces to a pressure different from the first space; a controller controlling the first and second pressure mechanisms such that the first and second spaces are adjacent to each other; a measuring unit measuring a flow rate of at least the first or second pressure mechanisms; and a determining unit determining an abnormality related to attracting/holding of the mold or substrate based on the flow rate.
1. A holding device used in a lithography apparatus for transferring a pattern formed on a mold to a substrate, for attracting and holding the mold or the substrate by a reduced pressure, the holding device comprising:
a holding unit configured to hold one of the mold or the substrate, and including a plurality of concave portions forming a plurality of spaces together with the mold or the substrate;
a first pressure mechanism including a vacuum pump configured to depressurize at least one first space among the plurality of spaces formed by the mold or the substrate and the holding unit;
a second pressure mechanism including a pressurizing pump configured to pressurize at least one second space among the plurality of spaces to a pressure different from that of the first space;
a controller configured to control the first and second pressure mechanisms so that the first and second spaces are adjacent to each other; and
a flow rate sensor configured to measure a flow rate of each of the first and second pressure mechanisms,
wherein the controller is configured to determine an abnormality related to attracting and holding of the mold or the substrate between the first space and the second space based on each of the measured flow rates, the abnormality including:
an increase in a gas flow rate between the first space and the second space due to a foreign substance sandwiched between the mold or the substrate and a holding surface of the holding unit between the first space and the second space; or
wear of the holding surface between the first space and the second space.
2. The holding device according to claim 1 , wherein the pressurizing pump applies a positive pressure.
3. The holding device according to claim 1 , further comprising a storage that stores the measured flow rates.
4. The holding device according to claim 3 , wherein the controller determines a type of the abnormality related to attracting and holding of the mold or the substrate based on a history of the stored measured flow rates.
5. The holding device according to claim 4 , wherein the controller determines whether the abnormality related to attracting and holding of the mold or the substrate is an abnormality due to:
the increase in the gas flow rate; or
the wear of the holding surface between the first space and the second space based on the history of the stored measured flow rates.
6. A lithographic apparatus for transferring a pattern formed on a mold to a substrate, the lithographic apparatus comprising:
an illumination optical system; and
a holding device for attracting and holding the mold or the substrate by a reduced pressure, and comprising:
a holding unit configured to hold one of the mold or the substrate, and including a plurality of concave portions forming a plurality of spaces together with the mold or the substrate;
a first pressure mechanism including a vacuum pump configured to depressurize at least one first space among the plurality of spaces formed by the mold or the substrate and the holding unit;
a second pressure mechanism including a pressurizing pump configured to pressurize at least one second space among the plurality of spaces to a pressure different from that of the first space;
a controller configured to control the first and second pressure mechanisms so that the first and second spaces are adjacent to each other; and
a flow rate sensor configured to measure a flow rate of each of the first and second pressure mechanisms,
where the controller is configured to determine an abnormality related to attracting and holding of the mold or the substrate between the first space and the second space based on each of the measured flow rates, the abnormality including:
an increase in a gas flow rate between the first space and the second space due to a foreign substance sandwiched between the mold or the substrate and a holding surface of the holding unit between the first space and the second space; or
wear of the holding surface between the first space and the second space.
7. A method of manufacturing an article using the lithographic apparatus of claim 6 , the method comprising:
transferring a pattern to a substrate using the lithographic apparatus; and
processing the substrate formed with the pattern.