Optimization of focused spots for maskless lithography
AssigneeCorning Incorporated
InventorPaul Francis Michaloski
Life of this patent
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Abstract
The focused spots of an active spot array projection system, such as a maskless lithographic projection system, are optimized within a relay of the projection system. A frequency modulator is positioned proximate to the pupil of the relay for reforming the focused spots while imaging the focused spots onto a photosensitive substrate.
Claims23
An active spot array projection system comprising
- an illuminator for illuminating addressable elements of a pattern generator,
- an imager for imaging the addressable elements of the pattern generator onto corresponding focusing elements that form focused spots at focal points of the focusing elements and in a pattern controlled by the pattern generator,
- a relay for relaying an image of the pattern of focused spots, each containing a range of spatial frequencies, onto a photosensitive substrate, and
- a frequency modulator proximate to a pupil of the relay for collectively modulating selected spatial frequencies in selected positions appearing inside the pupil of the relay for adjusting a shape of the focused spots on the photosensitive substrate.
A method of reforming focused spots within a controllable pattern of focused spots comprising steps of
- illuminating individually addressable elements of a pattern generator with an illuminator,
- imaging the addressable elements of the pattern generator onto corresponding focusing elements for forming focused spots at focal points of the focusing elements in a pattern controlled by the pattern generator,
- relaying the pattern of focused spots, each containing a range of spatial frequencies, through a common pupil and onto a substrate image plane, and
- collectively modulating selected spatial frequencies of the focused spots in selected positions appearing inside the common pupil so that images of the focused spots on the substrate image plane contain altered angular distributions of light for adjusting a shape of the focused spots on the substrate image plane.
In a maskless microlithographic projection system that produces a controllable array of focused spots for imaging patterns onto photosensitive substrates, an improvement comprising
- an imager for imaging addressable elements of a pattern generator onto corresponding focusing elements that form an array of focused spots at focal points of the focusing elements and in a pattern controlled by the pattern generator,
- a frequency modulator positioned within a relay of a projection lens that relays an image of the array of focused spots onto a photosensitive substrate, and
- the frequency modulator being arranged for collectively modulating selected spatial frequencies of the focused spots in selected positions appearing inside a pupil of the relay.
Dependencies are inferred from the claim text.