Abstract: Methods for determining a focus position of a lens system based on astigmatism. The methods can be used to monitor the focus of the lens system or to determine the flatness of a surface.

Abstract: A photolithography method for creating very small line dimensions includes making a mask by exposing a mask blank through a reticle in a reduction photolithography exposure tool, at a reduction of N. The fabricated mask is then placed in a second photolithography exposure tool at a second reduction M, to expose a wafer substrate at a reduction of M. The resulting patterned substrate will have a critical dimension equaling the critical dimension of the original reticle, divided by the factor N times M. In this manner, very small size patterns can be created even though a larger pattern starting reticle is used.

Abstract: A technique for improving across field dimensional control in a microlithography tool. In a lithography imaging process in which a pattern on a mask is projected to form latent images in a photosensitive medium, the critical dimension distribution across the imaging field varies due to scattering and other factors. An optical compensator having gradient neutral density filter properties is used to reduce the intensity of light at those locations corresponding to regions of an imaging field having higher exposure dose. By reducing the intensity of light at the higher dose regions, the overall dose profile is made more uniform, which reduces linewidth variations when devices are fabricated on an semiconductor wafer.

Abstract: A novel mask for photolithography in semiconductor processing and fabrication method is disclosed. The mask includes a layer of transmissive material transparent to the wavelength of light to be used deposited thereon. The transmissive material is plasma etched in accordance with a pattern in photoresist deposited thereon to create trench portions in the transmissive material. A layer of absorbing material absorptive to the wavelength of light to be used is deposited within the trench portions. The surface of the mask is then planarized to create a substantially smooth mask layer having trench portions in the transmissive material and absorbing layer portions within the trench portions. If desired, a second layer of transmissive material can be deposited over the smooth mask layer to provide a protective cap to create an overall smooth, flat completed mask surface. The mask is useful for transmissive photolithography applications as well as reflective photolithography applications.

Abstract: A novel mask for photolithography in semiconductor processing and fabrication method is disclosed. The mask includes a layer of transmissive material transparent to the wavelength of light to be used deposited thereon. The transmissive material is plasma etched in accordance with a pattern in photoresist deposited thereon to create trench portions in the transmissive material. A layer of absorbing material absorptive to the wavelength of light to be used is deposited within the trench portions. The surface of the mask is then planarized to create a substantially smooth mask layer having trench portions in the transmissive material and absorbing layer portions within the trench portions. If desired, a second layer of transmissive material can be deposited over the smooth mask layer to provide a protective cap to create an overall smooth, flat completed mask surface. The mask is useful for transmissive photolithography applications as well as reflective photolithography applications.