Nanonics Probes for Tough to Reach Places

Unique capabilities of Nanonics custom-made optical fiber probes continue to be developed.  In this paper, the specialized geometry of these probes to successfully measure various parameters in semiconductor devices is shown.  The area of critical dimension (CD) metrology is a well-known area in the semiconductor field where accurate measurement of critical dimensions such as deep trench depths, line edge roughness, linewidth, sidewall roughness and sidewall angles are critical and increasingly challenging as these dimensions continue to decrease. In the past decade, AFM has become a popular method to make these measurements of irregular features not possible with other common methods like SEM and TEM.

The sharp optical fiber probes with a tip length of upto 400um and an aspect ratio of 10:1 are uniquely suited to image sidewalls and deep trenches.  A schematic is shown below, left where the probe can easily fit into a deep trench and image along its bottom or its edges (right.) 

Using a Nanonics optical fiber probe, these challenging features were successfully measured, as shown in the image below.  These probes far surpass the ability of silicon probes, which cannot successfully measure steep sidewall angles, deep trenches, or bottom of trenches due to the geometry and shape of the silicon probe which skews the resulting image with artifacts.

Nanonics has an in-house probe fabrication facility with decades of experience between our scientists and engineers.  Our probes are provided exclusively to our customers, and we are always willing to help customize the probes to your research needs.

Published: H. Xie et al., Review of Scientific Instruments, 85, p. 123704 2014 

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