摘要:
Ultrafine patterns with dimensions smaller than the chemical and optical limits of lithography are formed by superimposing two photoresist patterns using a double exposure technique. Embodiments include forming a first resist pattern over a target layer to be patterned, forming a protective cover layer over the first resist pattern, forming a second resist pattern on the cover layer superimposed over the first resist pattern while the cover layer protects the first resist pattern, selectively etching the cover layer with high selectivity with respect to the first and second resist patterns leaving an ultrafine target pattern defined by the first and second resist patterns, and etching the underlying target layer using the superimposed first and second resist patterns as a mask.
摘要:
Ultrafine patterns with dimensions smaller than the chemical and optical limits of lithography are formed by superimposing two photoresist patterns using a double exposure technique. Embodiments include forming a first resist pattern over a target layer to be patterned, forming a protective cover layer over the first resist pattern, forming a second resist pattern on the cover layer superimposed over the first resist pattern while the cover layer protects the first resist pattern, selectively etching the cover layer with high selectivity with respect to the first and second resist patterns leaving an ultrafine target pattern defined by the first and second resist patterns, and etching the underlying target layer using the superimposed first and second resist patterns as a mask.
摘要:
Ultrafine patterns with dimensions smaller than the chemical and optical limits of lithography are formed by superimposing two photoresist patterns using a double exposure technique. Embodiments include forming a first resist pattern over a target layer to be patterned, forming a protective cover layer over the first resist pattern, forming a second resist pattern on the cover layer superimposed over the first resist pattern while the cover layer protects the first resist pattern, selectively etching the cover layer with high selectivity with respect to the first and second resist patterns leaving an ultrafine target pattern defined by the first and second resist patterns, and etching the underlying target layer using the superimposed first and second resist patterns as a mask.
摘要:
Ultrafine patterns with dimensions smaller than the chemical and optical limits of lithography are formed by superimposing two photoresist patterns using a double exposure technique. Embodiments include forming a first resist pattern over a target layer to be patterned, forming a protective cover layer over the first resist pattern, forming a second resist pattern on the cover layer superimposed over the first resist pattern while the cover layer protects the first resist pattern, selectively etching the cover layer with high selectivity with respect to the first and second resist patterns leaving an ultrafine target pattern defined by the first and second resist patterns, and etching the underlying target layer using the superimposed first and second resist patterns as a mask.
摘要:
A photolithographic projection system for transferring a predetermined pattern from a photomask to a wafer includes a radiation source and a grating mask. The radiation source projects radiation along a path through the photomask toward the wafer. The grating mask is positioned along the radiation path and is separate from the photomask. In a method for transferring a predetermined pattern from a photomask to a wafer, radiation is projected along a path through a grating mask and a photomask toward the wafer, and the grating mask is separate from the photomask.
摘要:
Methods of forming half-tone phase-shift masks include the steps of forming a series of layers on a face of a transparent substrate such as quartz. These layers include a phase-shift layer of MoSiON, a layer of opaque material (e.g., chrome) for blocking light on the phase-shift layer and a photoresist layer on the layer of opaque material. The photoresist layer is then patterned to define a mask having openings therein which expose the layer of opaque material. The layer of opaque material is then patterned using a wet etchant, to expose portions of the phase-shift layer. The patterned photoresist layer is then stripped and a cleaning step is then performed to remove residual defects and marks from the patterned layer of opaque material. The patterned layer of opaque material is then used as a mask during the step of anisotropically dry etching the phase-shift layer using a gas containing CF.sub.4 and O.sub.2, but not CHF.sub.3. The use of a gas containing CF.sub.4 and O.sub.2 inhibits parasitic sputtering of chrome from the patterned layer of opaque material onto the exposed portions of the face of the transparent substrate, during the dry etching step. In contrast, the use of a gas containing CHF.sub.3 and O.sub.2 during dry etching of the phase-shift layer may cause the formation of parasitic defects containing chrome on the face of the transparent substrate. These parasitic defects typically cause a reduction in yield when the phase-shift mask is used in the formation of integrated circuits.