Patent Number: 053171411
Section: summary

BACKGROUND OF THE INVENTION This invention relates to methods and apparatuses for alignment of objects, and relates in particular to alignment techniques for use in lithography in the manufacture of semiconductor devices. In the manufacture of semiconductor devices, a large number of patterning steps are carried out in the formation of complex, multi-layer structures. Each patterning step is carried out through lithographic techniques, involving exposure of selected portions of a resist to particles or light. In the fabrication of such multi-layer structures, it is extremely important that each pattern layer be aligned or in registration with, other layers in the structure. Mistakes in alignment or registration will result in unusable structures. Conventionally, registration is accomplished by optically locating alignment marks on the surface of a wafer. For example, a low energy laser beam may be projected on such an alignment mark on the wafer surface. Analysis of the reflected image then indicates the position of the lithographic system with respect to the alignment mark. The accuracy of optical alignment techniques is limited due to the limited resolution of light beams. Objects of the invention will become evident from the detailed description of a preferred embodiment which follows. SUMMARY OF THE INVENTION A method for alignment of a first object with a second object comprises the steps of determining the location of a feature on a surface of the second object using a probe of a scanned probe microscope, and positioning the first object in preselected spatial relationship with respect to the located feature. In an apparatus for performing lithography on a substrate, having a mask and mask holder supporting the mask, the improvement comprising means, comprising a probe of a scanned probe microscope, for determining the location of a feature on a surface of the substrate. A method of forming a probe of a scanned probe microscope on a substrate includes the steps of providing a first conductive base, having a tungsten surface layer, on the substrate; providing a dielectric layer and a layer comprising an organic compound on the first conductive base; opening a hole through the dielectric layer and the organic compound layer; and selectively depositing tungsten on the tungsten surface in the hole, whereby a probe having a substantially conical tip is formed in the hole. A method of forming a probe of an atomic force microscope includes the steps of forming a release layer on a substrate, forming a first metal layer on the release layer, forming a dielectric layer on the first metal layer, forming a second metal layer on the dielectric layer, providing a probe tip projecting from at least one of the first and second metal layers, providing a structure for maintaining the first and second metal layers at a predetermined separation, and removing the dielectric layer and the release layer.