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Microprobe-Based Cd Measurement Tool

IP.com Disclosure Number: IPCOM000037279D
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Nyyssonen, D: AUTHOR

Abstract

Disclosed is the design of a metrology tool which utilizes the atomic force microprobe (AFM) [1] as a surface sensor and is specifically designed for measuring trench depth and width at micrometer and smaller dimensions at approximately 1:1 and higher aspect ratios.

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Microprobe-Based Cd Measurement Tool

Disclosed is the design of a metrology tool which utilizes the atomic force microprobe (AFM) [1] as a surface sensor and is specifically designed for measuring trench depth and width at micrometer and smaller dimensions at approximately 1:1 and higher aspect ratios.

Unlike conventional scanning AFM systems 2, this design incorporates a two- dimensional length measurement system, such as a two-axis laser interferometer in addition to a two-dimensional laser heterodyne system which detects the change in resonance of the vibrating probe tip as it approaches the surface. The probe tip may be vibrated in either the horizontal or vertical direction depending upon which surface is being approached. The mean position of the probe tip is held stationary while the wafer or other part being measured is moved parallel or perpendicular to its surface and the displacement measured.

This design utilizes a three-point probe tip with well-defined sensor points for detecting the bottom, right and left edges of the trench. The probe tip is lowered into the trench using robotic motions. The tip is then moved from left to right at a specific height above the bottom of the trench. Trench widths are thereby measured as a function of height and, thus, edge slope can be determined. When the tip dimensions are known, accurate measurements of trench dimensions can be made. In addition, this system provides accurate control of tip position, thereby preve...