**A.2 Attachment of MWCNT by dielectrophoresis**

MWCNTs are attached to the tungsten tips not only to increase the spatial resolution but also to increase the aspect ratio as well. To attach the single MWCNT on chemically etched tungsten probe, sharpness of the tip, applied frequency, and field intensity are the key parameters. One electrode is the etched tungsten wire,

#### **Figure A10.**

*Simulation results of the algorithm for complicated hole and protrusion. (a) A random shape hole was drawn to check the versatility of the algorithm, where dark portion indicates the empty hole. (b) Line profile shows a simulation result of the tip trance. The tip starts scanning from the centre and move in along +X axis direction to find the side wall. Once the sidewall is detected, tip start to follow the boundary of the hole. Afterwards, one complete rotation is completed. (c) A random shape protrusion was drawn, where green portion represents the protrusion. (d) The simulation result of scanning shows a line profile of protrusion. Working methodology to scan the protrusion is the same as the hole.*

#### **Figure A11.**

*Cross section views of fractured AAO samples (a) in the middle part (b) near the bottom. Circles show the expected 3D scanning traces. Tip starts scanning from the bottom and raised a step along +Z direction as one rotation completed. Scale bar is 1 μm.*

while other electrode is a gold ring. AC voltages (6 V at 2.2 MHz) are applied to the electrodes, and CNTs are attached to the sharp edge of the tungsten tip. At this stage, van der Waals forces hold the CNTs, which are not strong enough to be used

*Raster scan image of silicon pillars using commercially available AFM using silicon cantilever. (a) Raster scan image with silicon cantilever showing that the AFM probe cannot go beyond 222 nm due to low aspect ratio. (b) Line profile of the silicon pillar which shows the height of one pillar is 120 nm as well as broad peak unlike the*

*Raster scan image of AAO sample using commercially available AFM with silicon cantilever. (a) Raster scan image with silicon cantilever showing that the AFM probe cannot go beyond 210 nm. (b) Line profile of the hole showing the depth of the hole is only 100 nm. However, original sample has depth around 1 μm. (c) 3D view*

*Measuring the Blind Holes: Three-Dimensional Imaging of through Silicon via Using High…*

*DOI: http://dx.doi.org/10.5772/intechopen.92739*

*real sample. However, original sample has height around 500* nm*. (c) 3D view of silicon pillars.*

for scanning purpose.

**Figure A13**

**277**

**Figure A12**

*of AAO sample.*

*.*

*.*

*Measuring the Blind Holes: Three-Dimensional Imaging of through Silicon via Using High… DOI: http://dx.doi.org/10.5772/intechopen.92739*

#### **Figure A12***.*

collected and dried under vacuum. Finally, CNT-PVA was dissolved into DI water and the solution is sonicated in an ultrasonic bath for 6 h to uniformly disperse in solution. After attachment of carboxylic group, MWCNTs were investigated by Fourier transform Infrared spectroscopy (FTIR), as shown in **Figure A4**. The peaks

stretching, respectively [29]. The peaks observed at 1260 and 1663 cm<sup>1</sup> are due to C–O and C=O stretching of functional groups, respectively [29]. In addition, C–H

MWCNTs are attached to the tungsten tips not only to increase the spatial resolution but also to increase the aspect ratio as well. To attach the single MWCNT on chemically etched tungsten probe, sharpness of the tip, applied frequency, and field intensity are the key parameters. One electrode is the etched tungsten wire,

*Simulation results of the algorithm for complicated hole and protrusion. (a) A random shape hole was drawn to check the versatility of the algorithm, where dark portion indicates the empty hole. (b) Line profile shows a simulation result of the tip trance. The tip starts scanning from the centre and move in along +X axis direction to find the side wall. Once the sidewall is detected, tip start to follow the boundary of the hole. Afterwards, one complete rotation is completed. (c) A random shape protrusion was drawn, where green portion represents the protrusion. (d) The simulation result of scanning shows a line profile of protrusion. Working methodology to*

*Cross section views of fractured AAO samples (a) in the middle part (b) near the bottom. Circles show the expected 3D scanning traces. Tip starts scanning from the bottom and raised a step along +Z direction as one*

observed at 1390 and 3425 cm<sup>1</sup> are identified with O–H bond bending and

stretching vibrations correspond to 2856 and 2924 cm<sup>1</sup> peaks [30].

**A.2 Attachment of MWCNT by dielectrophoresis**

*21st Century Surface Science - a Handbook*

**Figure A11.**

**276**

**Figure A10.**

*rotation completed. Scale bar is 1 μm.*

*scan the protrusion is the same as the hole.*

*Raster scan image of AAO sample using commercially available AFM with silicon cantilever. (a) Raster scan image with silicon cantilever showing that the AFM probe cannot go beyond 210 nm. (b) Line profile of the hole showing the depth of the hole is only 100 nm. However, original sample has depth around 1 μm. (c) 3D view of AAO sample.*

**Figure A13***.*

*Raster scan image of silicon pillars using commercially available AFM using silicon cantilever. (a) Raster scan image with silicon cantilever showing that the AFM probe cannot go beyond 222 nm due to low aspect ratio. (b) Line profile of the silicon pillar which shows the height of one pillar is 120 nm as well as broad peak unlike the real sample. However, original sample has height around 500* nm*. (c) 3D view of silicon pillars.*

while other electrode is a gold ring. AC voltages (6 V at 2.2 MHz) are applied to the electrodes, and CNTs are attached to the sharp edge of the tungsten tip. At this stage, van der Waals forces hold the CNTs, which are not strong enough to be used for scanning purpose.

*21st Century Surface Science - a Handbook*

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