Charged particle beam pattern transfer apparatus and method
AssigneeNikon Corporation
InventorMamoru Nakasuji
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Abstract
This invention concerns a charged particle beam pattern transfer system which uses a flux of charged particles, e.g. from an electron or ion beam, to transfer a mask pattern to a sensitized substrate. In particular, the invention is applicable to an electron beam reduction transfer system which demagnifies and transfers a mask pattern defined by multiple mask subfields to a sensitized substrate using the step-and-repeat transfer method. The invention provides a system for transferring the mask subfields, separated from one another on the mask by boundary strips, onto a wafer such that the transferred images of the mask subfields are joined together on the wafer as transfer subfields lacking any intervening boundary regions.
Claims21
A charged particle beam pattern transfer apparatus for transferring to a substrate a pattern defined by multiple subfields on a mask, the apparatus comprising:
- (a) a first main deflector set situated relative to an optical axis of the apparatus, the first main deflector set being operable to deflect toward the optical axis a charged particle beam that has passed through a mask subfield;
- (b) an imaging lens system operable to focus the charged particle beam deflected by the first deflector set;
- (c) a second main deflector set situated relative to the optical axis, the second main deflector set being operable to deflect, toward a transfer subfield on the substrate corresponding to the mask subfield, the charged particle beam focused by the imaging lens system;
- and
- (d) a first position-correcting deflector set situated relative to the optical axis between either the mask and the first main deflector set or the second main deflector set and the substrate, the first position-correcting deflector set being operable to deflect the charged particle beam and thus correct the position at which the charged particle beam, that has passed through a mask subfield, is incident upon the substrate so as to compensate for any discrepancies in the positions of the transfer subfields relative to each other compared to the positions of the mask subfields relative to each other.
In a moving-trajectory projection system for transferring a pattern from a mask to a substrate wherein the pattern is subdivided into a plurality of mask subfields each defining a separate portion of the pattern, the mask subfields being separated from one another by boundary regions that do not define any portion of the pattern, and the projection system including a moving trajectory optical system operable to cause a charged particle beam to pass through the mask subfields individually and form the pattern as an ordered assemblage of transfer subfields on a substrate, an improvement, comprising a position-correcting deflector set situated coaxially externally to the moving-trajectory optical system, the position-correcting deflector set being operable to deflect the charged particle beam so as to cause the portions of the pattern defined by the mask subfields to be transferred to the substrate as respective transfer subfields directly contacting each other in a serial manner without any intervening boundary regions.
A method for transferring a pattern, defined by plural mask subfields on a mask, each mask subfield defining a portion of the pattern and being separated from one another by boundary regions that do not define any portion of the pattern, from the mask to a substrate, the method comprising:
- (a) directing a charged particle beam to pass serially through plural mask subfields;
- (b) passing the beam through an optical system operable to deflect the beam sufficiently to cause the beam to be incident on a sensitive substrate so as to form on the substrate transfer subfields corresponding to the mask subfields through which the beam passed;
- (c) passing the beam through a first position-correcting deflector set situated coaxially with respect to the optical system and being operable to cause deflection of the beam sufficient to cause the portions of the pattern represented by the transfer subfields on the substrate to directly contact each other in a serial manner without any intervening boundary regions.
A charged particle beam pattern transfer apparatus for transferring to a substrate a pattern defined by multiple subfields on a mask, the apparatus comprising:
- (a) a first main deflector set situated relative to an optical axis of the apparatus, the first main deflector set being operable to reduce off-axis aberrations;
- (b) an imaging lens system operable to focus the charged particle beam deflected by the first deflector set;
- (c) a second main deflector set situated relative to the optical axis, the second main deflector set being operable to reduce off-axis aberrations;
- and
- (d) a first position-correcting deflector set situated relative to the optical axis between either the mask and the first main deflector set or the second main deflector set and the substrate, the first position-correcting deflector set being operable to deflect the charged particle beam and thus correct the position at which the charged particle beam, that has passed through a mask subfield, is incident upon the substrate so as to compensate for any discrepancies in the positions of the transfer subfields relative to each other compared to the positions of the mask subfields relative to each other.
Dependencies are inferred from the claim text.