Micromachined silicon probe for scanning probe microscopy

摘要

A microprobe having a mounting block and a silicon cantilever with an integral silicon tip is produced from a SOI wafer having a bottom layer of silicon substrate, a middle layer of insulating material, and a top layer of silicon substrate. The top layer is coated with a first layer of masking material. The bottom layer is masked and etched to form a bottom section of the mounting block. The middle layer provides an etch stop for precise control of the bottom layer etch. A tip mask is formed by partially etching the first layer of masking material. A front side mask is formed by further etching of the first layer. The front side mask defines a cantilever pattern and a top mounting block pattern. The cantilever pattern and the top mounting block pattern are transferred into the top layer by etching the top layer to a depth corresponding to a desired cantilever thickness. Further etching of the top layer forms a tip column and releases the cantilever and a top section of the mounting block from the top layer. The middle layer acts as an etch stop for precise control of the cantilever thickness and tip height. The tip column is then oxidized to form the integral silicon tip.