Projection lithography system and method using all-reflective optical elements
OwnerDavid Ross Shaferinventor
Life of this patent
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Abstract
A projection lithographic system that operates within the deep ultraviolet to vacuum ultraviolet region of the spectrum and uses an all-reflective optical arrangement to project a reduced image of a lithographic mask onto a semiconductor wafer. The all-reflective optical arrangement includes from six to eight reflective surfaces wherein each of the reflective surfaces is aspheric, The reflective surfaces are disposed along a common optical axis and are arranged not to interfere with the path of light as the light travel from the lithographic mask to the semiconductor wafer.
Claims20
An optical system for use in projection lithography where features from a lithographic mask are projected onto a semiconductor wafer using an exposure wavelength, said optical system comprising:
- at least six reflective surfaces disposed between said lithographic mask and said semiconductor wafer, wherein each of said reflective surfaces is aspheric.
A method of projecting a reduced image of a lithographic mask on a semiconductor wafer using an exposure wavelength, comprising the steps of:
- positioning at least six reflective aspheric surfaces between said lithographic mask and said semiconductor wafer, wherein each of said reflective surfaces is capable of reflecting said exposure wavelength;
- and
- reflecting said exposure wavelength from said at least six reflective aspheric surfaces wherein said reflective surfaces produce said reduced image on said semiconductor wafer.
Dependencies are inferred from the claim text.