Unpublished Work by Danish Hussain
We submitted this position paper in North East Asia Model United Nations Conference (NEAMUN) 2013.
Papers by Danish Hussain
IEEE/ASME Transactions on Mechatronics, 2015
ABSTRACT In this paper, a three-dimensional atomic force microscope (3DAFM) for imaging of the mi... more ABSTRACT In this paper, a three-dimensional atomic force microscope (3DAFM) for imaging of the micro- and nanoscale sidewall structures is presented. The system mainly consists of two individual scanners, each with two degrees of freedom to drive the probe on Y-Z plane for the feedback control and the sample on X-Y plane for the raster scan. A slender optical fiber probe is used and can be laterally tilted with a rotary holder, to access steep sidewalls with overhang or undercut features without any modification of the optical lever. Unlike the conventional AFM with the single-axis feedback control, the 3DAFM is capable of tracking 3D profiles of the sidewall structures with nonorthogonal scan due to the dual-axis feedback control with a vector probing scanning scheme. The motion vector angle of the probe is controllable and varied according to the slope angle of the sample surface for accurate scan of the sidewall with a uniform image density. The 3DAFM demonstrates great potential not only for characterization of 3D surface topography, also critical dimension (CD) measurements of the sidewall structures. 3D imaging and CD measurement results of an AFM calibration grating and micro-comb structure validate the capability and flexibility of the developed system.
Ultramicroscopy, Jan 17, 2015
A novel atomic force microscope (AFM) dual-probe caliper for critical dimension (CD) metrology ha... more A novel atomic force microscope (AFM) dual-probe caliper for critical dimension (CD) metrology has been developed. The caliper is equipped with two facing tilted optical fiber probes (OFPs) wherein each can be used independently to scan either sidewall of micro and nanostructures. The OFP tip with length up to 500μm (aspect ratio 10:1, apex diameter ⩾10nm) has unique features of scanning deep trenches and imaging sidewalls of relatively high steps with exclusive profiling possibilities. The caliper arms-OFPs can be accurately aligned with a well calibrated opening distance. The line width, line edge roughness, line width roughness, groove width and CD angles can be measured through serial scan of adjacent or opposite sidewalls with each probe. Capabilities of the presented AFM caliper have been validated through experimental CD measurement results of comb microstructures and AFM calibration grating TGZ3.
The Review of scientific instruments, 2014
We report a method to measure critical dimensions of micro- and nanostructures using the atomic f... more We report a method to measure critical dimensions of micro- and nanostructures using the atomic force microscope (AFM) with an optical fiber probe (OFP). This method is capable of scanning narrow and deep trenches due to the long and thin OFP tip, as well as imaging of steep sidewalls with unique profiling possibilities by laterally tilting the OFP without any modifications of the optical lever. A switch control scheme is developed to measure the sidewall angle by flexibly transferring feedback control between the Z- and Y-axis, for a serial scan of the horizontal surface (raster scan on XY-plane) and sidewall (raster scan on the YZ-plane), respectively. In experiments, a deep trench with tapered walls (243.5 μm deep) and a microhole (about 14.9 μm deep) have been imaged with the orthogonally aligned OFP, as well as a silicon sidewall (fabricated by deep reactive ion etching) has been characterized with the tilted OFP. Moreover, the sidewall angle of TGZ3 (AFM calibration grating) w...
Conference Papers by Danish Hussain
Massive Open Online Courses (MOOCs) are the latest installment in the field of distance education... more Massive Open Online Courses (MOOCs) are the latest installment in the field of distance education. This paper discusses the pros and cons of MOOCs in the educational systems with a special emphasis on the engineering education. Since 2012, more and more universities have been joining MOOC revolution and the number of online courses has considerably increased over time. Engineering MOOCs are also increasing. Due to their access to large audience, massive online courses have been expanding their horizon of admission to engineering education at all levels and improving the in-campus learning.
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Unpublished Work by Danish Hussain
Papers by Danish Hussain
Conference Papers by Danish Hussain