Correction of Thermal Expansion in a Lithographic Device

    公开(公告)号:US20230296989A1

    公开(公告)日:2023-09-21

    申请号:US18185280

    申请日:2023-03-16

    IPC分类号: G03F7/20

    CPC分类号: G03F7/7055 G03F7/70891

    摘要: A pattern writing method for charged-particle lithography apparatuses using an improved correction for thermal distortion of the substrate includes determining an exposure position where the beam impinges on the substrate and the power of the beam at the exposure position; calculating heating of the substrate at the exposure position, and calculating, for a plurality of locations over the substrate, and the thermal diffusion and radiative cooling; calculating, for the same or a reduced plurality of locations on the substrate, the positional change of the substrate due to thermal expansion; determining a displacement distance which compensates the positional change at the exposure position, updating the structure to be written by shifting the exposure position of the beam by said displacement distance, and writing the updated structures on the substrate with the beam. These steps are repeated as a function of time and/or varying exposure position of the beam substrate position.

    Method for Determining Focal Properties in a Target Beam Field of a Multi-Beam Charged-Particle Processing Apparatus

    公开(公告)号:US20240304415A1

    公开(公告)日:2024-09-12

    申请号:US18596458

    申请日:2024-03-05

    IPC分类号: H01J37/317 H01J37/153

    摘要: A method for determining focal properties in a target beam field of a charged-particle multi-beam processing apparatus is presented, where the focal properties relate to aperture images formed by the beamlets at or near the target within this apparatus, such as height of focus, astigmatic length, or size of blur. By modifying an electrostatic voltage of a lens or another suitable operating parameter of the projection optics, the landing angles of the beamlets are tilted by a small tilting angle, causing a small displacement of the positions where the beamlets hit the target surface. Using the amounts of displacement and the change of landing angles a map is generated that describes a mapping from the change of landing angles to the amounts of displacement as a function of the position, for instance by using a best fit to a predefined model; this map is then used to extract the focal properties, which in turn can be used to correct for imaging errors in the processing apparatus.