Method of overlay in extreme ultra-violet (EUV) lithography

摘要

Some embodiments of the present disclosure relate to a method of overlay control which utilizes a deformable electrostatic chuck. The method comprises exposing a substrate to radiation which is reflected off of a reticle. The reticle is mounted to a deformable electrostatic chuck by a plurality of raised contacts, where each raised contact is configured to independently vary in height from a surface of the deformable electrostatic chuck. After exposure of the substrate to radiation which is reflected off of the reticle, a displacement between a first alignment shape formed on a first layer disposed on a surface of the substrate and a second alignment shape formed by the exposure is measured. The height of one or more of the plurality of raised contact is changed based upon the displacement to alter a surface topology of the reticle, which negates some effects of clamping topology. Other embodiments are also disclosed.

主权项

1. An electrostatic chuck, comprising:
a first pattern of electrodes disposed within a dielectric layer which resides over a top surface of a first layer of insulating material; and a second pattern of raised contacts formed on a bottom surface of a second layer of insulating material which is substantially identical to the first pattern of electrodes; wherein a top surface of the second layer of insulating material comprises a third pattern of recessed areas which is substantially identical to the first and second patterns; and wherein a resistive material resides within each recessed area.