Probe Tip Wear Research Articles

A standard used for probe-tip diameter evaluation in surface roughness measurements using metrological atomic force microscope

Recently metrological atomic force microscopes (metrological AFMs) have been used for surface roughness measurements. The National Metrology Institute of Japan (NMIJ), AIST, provides a profile surface roughness calibration service using a metrological AFM based on ISO 19606:2017. This international standard requires evaluation of probe-tip diameter D and error in roughness measurements by using a standard plate with needle-shaped spikes before conducting surface roughness measurements. However, the conventional standard plate has several problems: (1) the needle-shaped spikes are too high, (2) the distance between spikes is too long, and (3) the spike curvature radius is not small enough, compared with AFM probe-tip size, which may lead to considerable uncertainty derived from probe-tip error evaluation. This study examined a new type of commercially-available standard plate as a candidate for probe-tip diameter evaluation. It features lower spike height and shorter distance between spikes in order to avoid probe-tip wear caused by repeated scanning. This study demonstrated that the overestimated uncertainty derived from probe-tip error evaluation can be corrected by using the new standard plate.

In-Process Atomic-Force Microscopy (AFM) Based Inspection.

A new in-process atomic-force microscopy (AFM) based inspection is presented for nanolithography to compensate for any deviation such as instantaneous degradation of the lithography probe tip. Traditional method used the AFM probes for lithography work and retract to inspect the obtained feature but this practice degrades the probe tip shape and hence, affects the measurement quality. This paper suggests a second dedicated lithography probe that is positioned back-to-back to the AFM probe under two synchronized controllers to correct any deviation in the process compared to specifications. This method shows that the quality improvement of the nanomachining, in progress probe tip wear, and better understanding of nanomachining. The system is hosted in a recently developed nanomanipulator for educational and research purposes.

Wear-Insensitive Sidewall Microprobe With Long-Term Stable Performance for Scanning Probe Microscopy Lithography

In this paper, a wear-insensitive sidewall microprobe with long-term stable performance is proposed. The proposed microprobe helps to reduce probe-tip wear and improve patterning stability in scanning probe microscopy lithography. The microprobe tip with a uniform cuboid-shape consists of a microscale mechanical contact and two nanoscale electrical contacts formed on the sidewall of the mechanical contact. The microscale mechanical contact reduces tip wear by dispersing the force applied to the tip, while the nanoscale electrical contact enables the sketching of nanoscale features. The uniform shape of the probe tip enables the probe to maintain its stable performance, even when it is mechanically worn. A prototype of the proposed microprobe with an 80-μm long mechanical line contact and a 30-nm long electrical line contact is fabricated using microelectromechanical systems techniques. The patterning stability of the fabricated microprobe in local anodic oxidation (LAO) lithography is investigated in terms of the change in the dimensions of the drawn lines and the shape of the probe tip before and after a 2-m scan. The results of the LAO lithography show that the fabricated microprobe could maintain a stable patterning performance after 2-m scan, which is an improvement of several thousand times over a conventional probe.

Study of sapphire probe tip wear when scanning on different materials

The accuracy of today's coordinate measuring machines (CMM) has reached a level at which exact knowledge of each component is required. The role of the probe tip is particularly crucial as it is in contact with the sample surface. Understanding how the probe tip wears off will help to narrow the measurement errors. In this work, wear of a sapphire sphere was studied for different scanning conditions and with different sample materials. Wear depth on the probe was investigated using an automated process in situ on the METAS micro-CMM and completed by measurements with an atomic force microscope. We often found a linear dependence between the wear depth and the scan length ranging from 0.5 to 9 nm m−1, due to variations in scan speed, contact force or sample material. In the case of steel, the wear rate is proportional to the scan speed, while for aluminum several processes seem to interact. A large amount of debris was visible after the tests. Except for aluminum, wear was visible only on the sphere and not on the sample. Sapphire/steel is the worst combination in terms of wear, whereas the combination sapphire/ceramic exhibits almost no wear.

Thermally-treated Pt-coated silicon AFM tips for wear resistance in ferroelectric data storage

In ferroelectric data storage, a conductive atomic force microscopy (AFM) probe with a noble metal coating is placed in contact with a lead zirconate titanate (PZT) film. The understanding and improvement of probe tip wear, particularly at high velocities, is needed for high data rate recording. A commercial Pt-coated silicon AFM probe was thermally treated in order to form platinum silicide at the near-surface. Nanoindentation, nanoscratch and wear experiments were performed to evaluate the mechanical properties and wear performance at high velocities. The thermally treated tip exhibited lower wear than the untreated tip. The tip wear mechanism is adhesive and abrasive wear with some evidence of impact wear. The enhancement in mechanical properties and wear resistance in the thermally treated film is attributed to silicide formation in the near-surface. Auger electron spectroscopy and electrical resistivity measurements confirm the formation of platinum silicide. This study advances the understanding of thin film nanoscale surface interactions.

A robust MEMS probe card with vertical guide for a fine pitch test

A vertically guided MEMS probe card was designed to deflect 50 µm at a force of 1.5 g and achieve less than 50 µm of pad pitch. Based on our experimental results, the measured average contact resistance of a device under test (DUT) was approximately 0.2 Ω at 1.44 g of force and the leakage current between two tips in the distance of one pitch was about 10 pA. In addition, tip planarity was about ±6 µm with x–y alignment errors within ±8 µm. A reliability test showed that the average contact resistance was 0.34 Ω and the probe tip wear was less than 1 µm after the 10 000 timed touchdowns. To be capable of fine pitch probing, a cantilever beam was constructed by dry etching using a positive photoresist. After the cantilever beam was formed by silicon etching using a deep RIE etcher inside a deep-recessed trench, a vertically guided structure was created from the cantilever beam. Furthermore, to make a horizontally stopped structure, the cantilever beam was designed to have a pyramid tip with a width bigger than that of the beam itself. This kind of structure is mechanically stable when the tip is applied with an oblique force. Because the probe card can be guided vertically and horizontally, it can be neither broken nor deformed by any directional force. In that respect, this newly proposed probe card is suitable for wafer-level testing and fine pitch device testing.

Nanoprobe Failure Analysis of Sub-100 nm CMOS Transistor Technologies

Abstract Probing in the sub-100 nm realm requires new tools and techniques that are relatively easy to learn if users follow the advice of the authors of this article. The authors present a probing method based on scanning probe technology and demonstrate its use on a 90-nm transistor failure due to a poly-silicon gate short. They also address challenges associated with sample preparation, probe tip contamination and wear, and the effects of vibration and drift.

Chemomechanical Nanolithography: Nanografting on Silicon and Factors Impacting Linewidth

We present a two-fold extension of previous work on Atomic Force Microscope-based chemomechanical functionalization: (1) chemomechanical nanografting, which extends chemomechanical functionalization to a more stable initial surface, and (2) linewidth studies that show the impact of force and Atomic Force Microscope probe tip wear on patterning resolution. Alkene, alcohol, and alkyl halide molecules were nanografted to silicon and imaged with in situ atomic force microscopy, time-of-flight secondary ion mass spectrometry with Automated eXpert Spectrum Image Analysis, and scanning electron microscopy. Chemomechanical nanografting demonstrated linewidths down to 50 nm. Lines written on hydrogen-terminated silicon were used to explore the impact of tip radius and tip wear on linewidth when using Si3N4 coated tips.

Fabrication of Grooves on Aluminum Surface with Atomic Force Microscope Probe Processing

Aluminum specimens covered with anodic oxide films were scratched with an atomic force microscope (AFM) probe in air, pure water, solutions, Cu-electroless plating solution, and diluted NaOH solutions to examine the effect of the probe load, scratch number, and processing environment on the rate of groove development. The rest potential of the aluminum was monitored during scratching in the solutions, and in situ AFM observations were carried out after the scratching. Probe wear was also examined in pure water and NaOH solution. The rate of groove development was in the order solution, and decreased with decreasing probe load and increasing scratch number. The rest potential remained steady in the solutions during scratching with loads below 12.5 μN, while it dropped rapidly above 25 μN. Copper was deposited in and around grooves during scratching in and Cu-electroless plating solution at the high loads, and after the scratching copper deposits grew only during immersion in Cu-electroless plating solution. Probe-tip wear was greater in NaOH solution than in distilled water. © 2001 The Electrochemical Society. All rights reserved.

Improved atomic force microscopy imaging using carbon-coated probe tips

Atomic force microscopy (AFM) images using carbon-coated probe tips are presented for hydrogen-passivated Si and SiO2 surfaces. Tapping mode measurements on these surfaces demonstrate that the image quality and probe tip wear characteristics are dramatically improved for scans performed with the carbon coated tips. The reasons for the improved quality of AFM imaging and reduced tip damage are discussed.