# US 5,345,816 A · Integrated tip strain sensor for use in combination with a single axis atomic force microscope > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,345,816 A - Document ID: US5345816A - Status: Granted - Kind: A - Application number: 08/157,800 - Filed: 1993-11-24 - Granted: 1994-09-13 - Earliest claimed: 1992-12-31 - Assignees: International Business Machine Corporation - Inventors: Joachim Clabes; Henri A. Khoury; Laszlo Landstein - Web page: https://patentgrep.com/patent/US5345816A ## CPC - G01Q 60/38: Probes, their manufacture, or their related instrumentation, e.g. holders - B82Y 35/00: Methods or apparatus for measurement or analysis of nanostructures - G01B 7/012: Contact-making feeler heads therefor - G01Q 20/04: Self-detecting probes, i.e. wherein the probe itself generates a signal representative of its position, e.g. piezoelectric gauge - G03F 7/70633: {Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching} - Y10S 977/852: for detection of specific nanostructure sample or nanostructure-related property - Y10S 977/878: Shape/taper - G01Q: SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM] - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract An integrated tip strain sensor is combination with a single axis atomic force microscope (AFM) for determining the profile of a surface in three dimensions. A cantilever beam carries an integrated tip stem on which is deposited a piezoelectric film strain sensor. A high-resolution direct electron beam (e-beam) deposition process is used to grow a sharp tip onto the silicon (Si) cantilever structure. The direct e-beam deposition process permits the controllable fabrication of high-aspect ratio, nanometer-scale tip structures. A piezoelectric jacket with four superimposed elements is deposited on the tip stem. The piezoelectric sensors function in a plane perpendicular to that of a probe in the AFM; that is, any tip contact with the linewidth surface will cause tip deflection with a corresponding proportional electrical signal output. This tip strain sensor, coupled to a standard single axis AFM tip, allows for three-dimensional metrology with a much simpler approach while avoiding catastrophic tip "crashes". Two-dimensional edge detection of the sidewalls is used to calculate the absolute value or the linewidth of overlay, independent of the AFM principle. The technique works on any linewidth surface material, whether conductive, non-conductive or semiconductive. ## Claims ### Claim 1 A method of manufacturing an integrated tip strain sensor in combination with an atomic force microscope (AFM) for profiling a surface in three dimensions, the method comprising the steps of: using a high resolution direct electron beam (e-beam) deposition process to grow a tip on a tip stem integral with a cantilever beam structure; depositing a continuous piezoelectric material coating on the tip stem; treating said piezoelectric material in an oxygen-containing environment to crystallize said piezoelectric material into a proper phase and to oxidize the exposed cantilever beam structure, thereby achieving an electrical insulating coating on the same; applying a metal film onto the piezoelectric material coating and at least a bottom surface of the cantilever beam structure as an overcoat to form strain sensor contacts; and patterning the metal film to yield electrical conductors which extend along the tip stem and along a bottom length of the cantilever beam structure to provide output signal lines from the strain sensor contacts. ### Claim 2 (depends on 1) The method recited in claim 1 further comprising the step of etching said piezoelectric material coating into four quadrants. ### Claim 3 (depends on 1) A method as recited in claim 1, wherein said cantilever structure comprises silicon. ### Claim 4 (depends on 1) A method as recited in claim 1, wherein said piezoelectric material comprises lead zirconate titanate (PZT). ### Claim 5 (depends on 1) A method as recited in claim 1, wherein said piezoelectric material is lead zirconate titanate (PZT). ### Claim 6 (depends on 1) A method as recited in claim 1, wherein said step of patterning comprises using a laser ablation technique. ### Claim 7 (depends on 1) A method as recited in claim 1, wherein said step of patterning comprises using an ion milling technique. ### Claim 8 (depends on 1) A method as recited in claim 1, wherein said step of patterning comprises using an e-beam patterning technique. ### Claim 9 (depends on 1) A method as recited in claim 1, wherein said cantilever structure is formed of silicon. ### Claim 10 (depends on 1) A method as recited in claim 1, wherein said treating step comprises heat treating said piezoelectric material in an oxygen-containing environment. ### Claim 11 (depends on 1) A method as recited in claim 1, wherein said treating step comprises heat treating said piezoelectric material in an oxygen-containing environment to crystallize said piezoelectric material into a proper phase and to oxidize the exposed cantilever structure and the tip stem. ### Claim 12 (depends on 1) A method as recited in claim 1, wherein said applying step comprises applying a continuous metal film onto the piezoelectric material coating and at least the bottom surface of the cantilever beam as an overcoat.