Process for manufacturing ultra-sharp atomic force microscope (afm) and

Abstract

A method for manufacturing probe tips suitable for use in an atomic force microscope (AFM) or scanning tunneling microscope (STM) begins by depositing a layer of a first material over a substrate and then patterning the layer of the first material to define apertures wherever probe tips are to be formed. Next, a layer of a second material is deposited using an unbiased high density plasma chemical vapor deposition (HDPCVD) process to form sharp probe tips in the apertures in the layer of the first material. The HDPCVD process also forms a sacrificial layer of the second material on top of the portions of the first material not removed by the patterning step. The sacrificial layer at least partially overhangs the apertures in the first material, forming a shadow mask during the deposition process which gives rise to a sharp probe profile. After the formation of the probe tips, the remaining portion of the layer of first material is removed using a wet chemical etchant that selectively etches the first material at a much higher rate than the second material. The removing step also removes the sacrificial layer of the second material because the sacrificial layer is lifted off the substrate when the underlying layer of first material is etched away. In one preferred embodiment, the first material is silicon nitride and the second material is silicon dioxide.