CMOS-MEMS dynamic FM atomic force microscope

Sarkar, Niladri; Lee, G.; Mansour, Raafat R.

doi:10.1109/transducers.2013.6626917

Cited by 15 publications

(6 citation statements)

References 9 publications

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“…The high tip-sample interaction forces resulted in significant tip wear. Dynamic modes of operation were then developed in order to increase the tip-sample force sensitivity and thereby reduce tip wear [188]. AM-AFM and FM-AFM were both observed to improve imaging performance significantly.…”

Section: Applications Of Isothermal Scannersmentioning

confidence: 99%

Single‐Chip Scanning Probe Microscopes

Sarkar

Mansour²

2015

Micro‐ and Nanomanipulation Tools

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Scanning probe microscopes (SPMs) are the highest resolution imaging instruments available today and are among the most important tools in nanoscience. Conventional SPMs suffer from several drawbacks owing to their large and bulky construction and to the use of piezoelectric materials. Large scanners have low resonant frequencies that limit their achievable imaging bandwidth and render them susceptible to disturbance from ambient vibrations. Array approaches have been used to alleviate the bandwidth bottleneck; however as arrays are scaled upwards, the scanning speed must decline to accommodate larger payloads. In addition, the long mechanical path from the tip to the sample contributes thermal drift. Furthermore, intrinsic properties of piezoelectric materials result in creep and hysteresis, which contribute to image distortion. The tip-sample interaction signals are often measured with optical configurations that require large free-space paths, are cumbersome to align, and add to the high cost of state-of-the-art SPM systems. These shortcomings have stifled the widespread adoption of SPMs by the nanometrology community. Tiny, inexpensive, fast, stable and independent SPMs that do not incur bandwidth penalties upon array scaling would therefore be most welcome. A method to increase the quality factor (Q-factor) of flexural resonators is introduced. The method relies on an internal energy pumping mechanism that is based on the interplay between electrical, iv mechanical, and thermal effects. To the best of the author's knowledge, the devices that are designed to harness these effects possess the highest electromechanical Qs reported for flexural resonators operating in air; electrically measured Q is enhanced from ~50 to ~50,000 in one exemplary device. A physical explanation for the underlying mechanism is proposed.The design, fabrication, imaging, and tip-based lithographic patterning with the first single-chip Scanning Thermal Microscopes (SThMs) are also presented. In addition to 3 DOF scanning, these devices possess integrated, thermally isolated temperature sensors to detect heat transfer in the tip-sample region.Imaging is reported with thermocouple-based devices and patterning is reported with resistive heater/sensors. An "isothermal electrothermal scanner" is designed and fabricated, and a method to operate it is detailed. The mechanism, based on electrothermal actuation, maintains a constant temperature in a central location while positioning a payload over a range of >35μm, thereby suppressing the deleterious thermal crosstalk effects that have thus far plagued thermally actuated devices with integrated sensors.

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Section: Applications Of Isothermal Scannersmentioning

confidence: 99%

Single‐Chip Scanning Probe Microscopes

Sarkar

Mansour²

2015

Micro‐ and Nanomanipulation Tools

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“…A manual coarse approach mechanism was used to lower the tip and to engage the sample, as discussed in [13]. Once the tip was in contact, a controller was used to maintain constant amplitude from the piezoresistive bridge circuit while the lateral actuators scanned over the surface of the sample.…”

Section: Imaging Of Calibration Gratingsmentioning

confidence: 99%

“…A CMOS-MEMS probe was presented in [10]. We have reported the first imaging results with single-chip AFMs in the contact [11], intermittent contact [12], and frequency modulation (FM) [13] modes.…”

Section: Introduction Scanning Probe Microscopy (Spm) and Memsmentioning

confidence: 99%

Single-chip atomic force microscope with integrated Q-enhancement and isothermal scanning

Sarkar¹,

Mansour

2014

2014 IEEE 27th International Conference on Micro Electro Mechanical Systems (MEMS)

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We present the highest resolution imaging performance attained to date with a single-chip Atomic Force Microscope (AFM) that does not require off-chip scanning or sensing hardware. The marked improvement in sensitivity of the instrument stems in part from an internal quality (Q) factor enhancement mechanism that relies on the interplay between effects in the electrical, thermal and mechanical domains. In addition, careful matching of the strain sensor in an electrothermally actuated, piezoresistively detected resonant cantilever improves the dynamic range of the instrument. Furthermore, an integrated isothermal electrothermal scanner has been developed to scan a surface area of ~50μm x ~15μm while maintaining a constant temperature at the tip and sensor locations, thereby suppressing the deleterious thermal crosstalk effects that have plagued previously reported electrothermal scanner designs.

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“…Atomic force microscopy has the ability to make high resolution measurements (subnanometer-scale) and is widely utilized in scientific and industrial applications. However, there are two main setbacks to the use of AFM metrology in in-line manufacturing applications [2]. The first is the scanning speed of the AFM tip and the second is the time it takes to place and align samples in the AFM.…”

Section: Introductionmentioning

confidence: 99%

“…Flexure bearings are used in this system because of their precision and mechanical simplicity [4,5]. The flexure bearings are used to position the single-chip AFMs relative to the wafer that is [2] being inspected. The precision positioning stage is designed to be able to achieve millimeter-scale displacements with micron level precision.…”

Section: Introductionmentioning

confidence: 99%

In-Line Dimensional Metrology in Nanomanufacturing Systems Enabled by a Passive Semiconductor Wafer Alignment Mechanism

Yao

Duenner

Cullinan

2016

Journal of Micro and Nano-Manufacturing

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One of the major challenges in nanoscale manufacturing is defect control because it is difficult to measure nanoscale features in-line with the manufacturing process. Optical inspection typically is not an option at the nanoscale level due to the diffraction limit of light, and without inspection high scrap rates can occur. Therefore, this paper presents an atomic force microscopy (AFM)-based inspection system that can be rapidly implemented in-line with other nanomanufacturing processes. Atomic force microscopy is capable of producing very high resolution (subnanometer-scale) surface topology measurements and is widely utilized in scientific and industrial applications, but has not been implemented in-line with manufacturing systems, primarily because of the large setup time typically required to take an AFM measurement. This paper introduces the design of a mechanical wafer-alignment device to enable in-line AFM metrology in nanoscale manufacturing by dramatically reducing AFM metrology setup time. The device consists of three pins that exactly constrain the wafer and a nesting force applied by a flexure to keep the wafer in contact with the pins. Kinematic couplings precisely mate the device below a flexure stage containing an array of AFM microchips which are used to make nanoscale measurements on the surface of the semiconductor wafer. This passive alignment system reduces the wafer setup time to less than 1 min and produces a lateral positioning accuracy that is on the order of ∼1 μm.

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CMOS-MEMS dynamic FM atomic force microscope

Cited by 15 publications

References 9 publications

Single‐Chip Scanning Probe Microscopes

Single‐Chip Scanning Probe Microscopes

Single-chip atomic force microscope with integrated Q-enhancement and isothermal scanning

In-Line Dimensional Metrology in Nanomanufacturing Systems Enabled by a Passive Semiconductor Wafer Alignment Mechanism

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