Development of a virtual probe tip with an application to high aspect ratio microscale features

Abstract

Nondestructive measurement of microscale features remains a challenging metrology problem. For example, to assess a high aspect ratio small hole it is currently common to cut a cross section and measure the features of interest using an atomic force microscope, scanning probe microscope, or scanning electron microscope. Typically, these metrology tools may be suitable for surface finish measurement but often lack the capability for dimensional metrology. The aim of this article is to discuss the development of a high aspect-ratio microscale probe for measurement of microscale features. A 700:1 high aspect ratio probe shank is fabricated with a 7 m diameter, and attached at one end to an oscillator. The oscillator produces a standing wave in the oscillating probe shank as opposed to conventional probes that use a microscale sphere on the end of a comparatively rigid shank. As a result of the standing wave formed in steady state vibration, the free end of the shank generates an amplitude of oscillation greater than the probe shank diameter. Thus, the probe does not require a spherical ball to serve as the contact point and simply uses the contact diameter of the free end of the vibrating shank. This methodology is referred to as a virtual probe tip. The virtual probe tip in conjunction with a nanopositioning scanner is used to measure surface profile measurements over traverse lengths of 130 m. In this article, results from profiles of a 500 nm step height and a ruby sphere of diameter 1 mm are presented. Experiments in this article indicate the ability to repeatedly resolve surface features of less than 5 nm while maintaining bandwidths greater than 1 kHz. Furthermore, adhesion problems often encountered with micrometer scaled probes were not observed during profile measurements with this virtual probe.

Development of Touch Probing System Using a Fiber Stylus

“…However, it is very difficult to precisely measure the shapes of micro-holes that have large length/diameter (L/D) ratios because of the difficulties encountered during probe fabrication and the complexities involved in employing a sensing method that uses a small measuring force. Many studies have been reported on micro-hole measurement techniques employing a variety of probes such as optical probes [1][2][3], vibroscanning probes [4,5], vibrating probes [6][7][8][9][10][11][12], tunneling effect probes [12,13], opto-tactile probes [14], fiber probes [15,16], optical trapping probes [17], and diaphragm or flexure based probes using an elastic mechanism [18][19][20][21][22][23][24][25][26][27].…”

Overview of 3D Micro- and Nanocoordinate Metrology at PTB

“…In addition, the contact mode microprobes usually apply styli with a limited aspect ratio to achieve a better measurement stability. To mitigate these problems, non-contact mode micro-CMM probes have been developed [21][22][23]. In the non-contact measurement mode, the probes are vibrated and the change of the vibration amplitude due to the probe sample's interaction is usually applied for measurements.…”

“…In the non-contact measurement mode, the probes are vibrated and the change of the vibration amplitude due to the probe sample's interaction is usually applied for measurements. For instance, Bauza et al [21] developed a high-aspect-ratio microprobe using a probe shank with a diameter of 7 µm having an aspect ratio of 700:1. During the measurements, its probe shank is oscillated in a standing wave.…”

“…Various micro-CMM probes have also been developed [4,11,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Most of them are mechanical tactile probes working in the contact mode [4,11,[15][16][17][18][19].…”

Development of a System for Measuring Micro Hole Accuracy Using an Optical Fiber Probe

“…Many studies have been reported on micro hole measurement techniques that employ a variety of probes, such as optical probes, vibroscanning probes, vibrating probes, tunneling effect probes, opto-tactile probes, fiber deflection probes, optical trapping probes, diaphragm probes [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], among others. This paper presents a system of micro hole measurement using an optical fiber probe that is available as a low-force displacement probe and has a wide measuring range [16].…”