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### About Nanotechnology: A Maker’s Course

How can we make structures that are 10,000 times smaller than the width of human hair? How can we “see” things at the nano-scale? In this course, you will learn a lot about the capabilities of nanotechnology tools and how to use them for nano-scale fabrication and characterization through lectures and lab demonstrations.

The next frontier of the Maker culture is the nanoscale, where ideas become real. To become a Nanotechnology Maker pioneer, we’ll teach you the knowledge, skills, and tools you need to turn your nanotechnology ideas into real things and take pictures of things at the nano-scale.

Through the Research Triangle Nanotechnology Network, experts in nanofabrication, electron beam microscopy, and nano-characterization put together this course (RTNN). Through the US National Nanotechnology Coordinated Infrastructure program, the RTNN trains schools and businesses on how to use the tools shown in this course. The RTNN makes the tools shown in this course available to anyone who wants to use them.

Course Apply Link – Nanotechnology: A Maker’s Course

### Week 01

#### Practice Quiz: for Introduction

Q1. Which of the following are types of information we can get from a nano-measurement tool?

• Elemental/Chemical Composition
• Hardness
• Geometry
• Size

Q2. An optical microscope uses light to produce an image, whereas an electron microscope uses _____________.

Q3. If you needed to measure the length of DNA, what type of measurement tool can you use?

• Optical Microscope
• Ruler
• Electron Microscope
• Tape measure

Q4. Which of the following are typically conductive? Select all that apply

• Dielectrics/Ceramics
• Biologicals
• Silver
• Metal
• Gold
• Polymers

Q5. Lasers are only used in high-tech nanotechnology facilities – but not my home.

• True
• False

Q6. The photolithography technique mentioned in the Introduction to Nanofabrication Tools can produce features as small as:

• one angstrom
• one nanometer
• meters
• a couple of microns wide

Q7. Particles in the open air can cause defects in thin film deposition

• True
• False

#### Practice Quiz : for Essential Technologies for Nano

Q1. In the cleanroom demonstration video, the cameraman did not need to gown up in order to enter the cleanroom.

• True
• False

Q2. When preparing to enter the cleanroom, we put on gloves first or last?

• First
• Last

Q3. Which of the following has more air molecules inside (per unit volume)?

• Cleanroom
• Vacuum

Q4. Name the units used to measure pressure. (Select all that apply)

• Pascal
• Torr
• Kelvin
• Celsius
• Meters

Q5. Which of the following are found in the electromagnetic spectrum? (Select all that apply)

• Time wave
• Visible Light
• Echo wave
• Alpha ray
• Gamma rays

Q6. What is the best resolution of a microscope with a numerical aperture of 0.12 using energy with a wavelength of 400 nm?

• 200.0 nm
• 2.0 microns
• 3.3 nm
• 3.3 microns

Q7. As the velocity of an electron decreases the wavelength of the electron will ________.

• stay the same
• decrease
• increase

Q8. What can occur when an electron beam interacts with a sample? (Select all that apply)

• The beam will create a vacuum.
• The beam will create a hologram image of the sample.
• Electrons in the beam will multiply as they hit the sample
• The beam will pass through the sample
• Electrons in the beam will become trapped in the sample

#### Main: Introduction and Essential Technologies for Nano

Q1. Nano-measurement tools typically involve bombarding a sample with particles such as:

• ball bearings
• electrons
• photons
• ions
• bacteria
• dust
• vacuum

Q2. What are challenges of nanoscale measurement compared to traditional measurement? (Select all that apply.)

• Can’t find a nanoruler at hardware stores
• The equipment is not readily available
• Humans can’t see at that scale with their naked eye
• Not every material can be characterized at the nanoscale

Q3. Which of the following are not typically conductive? Select all that apply

• Silver
• Polymers
• Gold
• Dielectrics/Ceramics
• Metals
• Biologicals

Q4. Particles in the open air do not cause defects in thin film deposition.

• True
• False

Q5. Which of the following are methods used to deposit thin films? (Select all that apply)

• Nano-imprint Lithography
• Screenprinting
• Chemical Vapor Deposition
• Vacuum Evaporation
• Painting
• Photolithography
• E-Beam Lithography
• Sputter Deposition
• Etching

Q6. When gowning before entering the cleanroom, you:

• start at the top (head) and work down to the bottom (feet)
• start at the bottom (feet) and work up to the top (head)

Q7. Typical molecules found in air include _____ (check all that apply)

• carbon dioxide
• silicon dioxide
• nitrogen
• oxygen
• silver

Q8. Match the vacuum pump categories to their general function:

a. Positive Displacement Pumps _____

b. Momentum Transfer Pumps _____

c. Entrapment Pumps _____

1. trap air molecules inside the pump, effectively removing the molecules from the chamber

2. bounce or deflect air molecules out of the chamber

3. push air out of the chamber

• a-3, b-1, c-2
• a-1, b-2, c-3
• a-2, b-1, c-3
• a-2, b-3, c-1
• a-3, b-2, c-1
• a-1, b-3, c-2

Q9. Which of the following are found in the electromagnetic spectrum? (Select all that apply)

• Time wave
• Seismic wave
• Beta ray
• Alpha ray
• Microwaves

Q10. What is the best resolution of a microscope with a numerical aperture of 0.5 using energy with a wavelength of 2.8 nm?

• 3.36 nm
• 5.6 nm
• 3.36 pm
• 5.6 microns

Q11. As the velocity of an electron increases the wavelength of the electron will ________.

• stay the same
• decrease
• increase

Q12. What can occur when an electron beam interacts with a sample? (Select all that apply)

• Electrons in the beam will gain mass as they hit the sample.
• Electrons in the beam will multiply as they hit the sample.
• The beam will create a vacuum.
• Electrons in the beam will knock electrons out of the sample.
• The beam will pass through the sample.

### Week 02

#### Practice Quiz for Scanning Electron Microscopy

Q1. What is an advantage of using an environmental scanning electron microscope?

• The images are at a higher magnification than traditional SEM.
• The electron beam energy required to generate images is significantly lower.
• The process is completely automated and operators do not need to be trained on the equipment.
• A vacuum environment is not required.
• Water in the sample can be used to prevent charging, eliminating the need for conductive coating.

Q2. Which of the following statements are true? Select all that apply.

1 point

• The contrast that we see in a backscatter image is due to differences in electron velocity as it interacts with the sample.
• In backscattered SEM images, regions of the sample with higher atomic number will produce more backscattered electrons and appear bright.
• The contrast that we see in a backscatter image is due to differences in average atomic number.
• Secondary electron images show few surface features of a sample and look flat.

Q3. Which of the following uses glass lenses to focus their energy source?

• Light microscope
• Electron microscope

Q4. In SEM, what is the sample mounted on to prepare for imaging?

• The lab bench
• A paper towel
• A microscope stage
• A sample stub

Q5. In SEM, after loading the sample and pumping the chamber to a low pressure, what should be done first before collecting an image?

• Turn the electron beam on and off to calibrate it
• Scan the entire surface to look for defects
• Focus the electron beam on the sample
• Zero the detector settings

Q6. Images collected by the secondary electron detector appear ________ (Select the best answer).

• Flat
• Out-of-focus
• Dim
• Three-dimensional

#### Practice Quiz on Energy-dispersive X-ray Spectroscopy

Q1. After Energy Dispersive X-Ray Spectroscopy (EDS) is performed on a sample, it can be reused in further tests.

• True
• False

Q2. Which of the following may be components used in an Energy Dispersive X-Ray Spectroscopy (EDS) measurement? (Select all that apply)

• X-Ray Detector
• Electron Gun
• Electron Microscope
• Diffractometer
• Software

Q3. In Energy Dispersive Spectroscopy (EDS), it’s impossible to misidentify elemental composition of a sample.

• True
• False

Q4. How might functions of the electron microscope be used in an Energy Dispersive X-Ray Spectroscopy (EDS) experiment?

• Imaging (Focusing)
• Altering beam conditions
• Spectroscopy
• All of the above

#### Main : Nano Measurement and Characterization Tools: Scanning Electron Microscopy and Energy-Dispersive X-ray Spectroscopy

Q1. What is an advantage of using an environmental scanning electron microscope?

• Samples can be coated with less expensive metals to prevent charging.
• The resolution is typically higher than traditional SEM.
• Wet samples can be imaged in their natural state without being dried.
• Images can be collected much more rapidly.

Q2. If you are interested in collecting SEM images that highlight surface features of your sample, which detector would be more appropriate?

• Backscatter
• Secondary electron

Q3. Which of the following uses electrons to generate images?

• Light microscope
• Electron microscope

Q4. In SEM, which of the following materials is often used to coat nonconductive samples?

• Polymer
• Glass
• Carbon
• Acetone

Q5. In SEM, after loading the sample and pumping the chamber to a low pressure, what is the first thing that should be done before collecting an image?

• Move the sample out of the chamber.
• Tighten the set screws on the sample stage.
• Focus the electron beam on the sample.
• Coat the sample with a conductive layer.

Q6. Which of the following information can be obtained through Energy Dispersive X-Ray Spectroscopy? (Select all that apply)

• Mass
• Weight
• Elemental Composition
• Feature Size
• Chemical Composition

Q7. What makes each element have a unique fingerprint in Energy Dispersive Spectroscopy (EDS)?

• Atomic number of elements in the sample
• Electron energy states in the element
• Mass of the atoms in the sample
• Amount of atoms in the sample

Q8. If an insulating sample is coated with a very small layer of gold to produce better images, gold will not be detected in the Energy Dispersive X-Ray Microscopy (EDS) experiment.

• True
• False

### Week 03

#### Practice quiz on Transmission Electron Microscopy

Q1. What type of samples can be used in a Transmission Electron Microscope?

• Large Samples
• Bulky Samples
• Thick Samples
• Thin Samples

Q2. Samples for TEM are often polished into a ________ shape.

• Donut
• Disc
• Wedge
• Square

Q3. True/False: Beam alignment is a critical step in TEM.

• True
• False

Q4. True/False: Focusing the x-ray beam is an important part of TEM.

• True
• False

Q5. True/False: Most of the time samples are readily thin enough for TEM imaging and do not require processing.

• True
• False

#### Practice Quiz on Cryo-Transmission Electron Microscopy

Q1. In the context of transmission electron microscopy, which term would not describe Soft Materials?

• biological samples
• samples contained in liquid
• papers
• ceramic samples

Q2. Preparing biological samples for TEM imaging requires that the samples be chemically fixed using what chemical?

• formaldehyde
• polyimide
• glyceride
• bromide

#### Main : Nano Measurement and Characterization Tools: Transmission Electron Microscopy

Q1. What is the major difference between SEM and TEM?

1 point

• Only TEM produces images of the sample
• Insulating samples can only be imaged in SEMs
• TEM uses smaller electrons than SEMs
• The electrons must pass through the sample in TEM

Q2. What are challenges of TEM? (Select all that apply)

• Aberrations related to lenses limit spatial resolution
• Requires ultrathin samples
• Sample image is a projection from 3D to 2D
• Environment around the microscope must be precisely controlled

Q3. In TEM, small changes in the environment, like vibrations from someone talking or a slight increase in temperature can affect imaging dramatically.

• True
• False

Q4. Using TEM, a researcher is able to image individual atoms.

• True
• False

Q5. What does a plasma cleaner do to a TEM sample?

• Washes the sample with detergent
• Coats the sample with a thin, clean layer of material
• Coats the sample with a conductive layer
• Removes debris and other particulates

Q6. Plunge freezing is a sample preparation method used for Cryo-TEM in which the sample is slowly cooled down.

• True. The sample should be frozen gradually.
• False. The sample should be cooled very rapidly.

Q7. Which is not a type of ice that can form at atmospheric pressure?

• vitreous
• hexagonal
• cubic
• octagonal

Q8. When performing biological sample prep for the TEM, which is not required safety equipment?

• lab coat
• safety glasses
• gloves
• ear plugs

Q9. The inside of the TEM is always under vacuum?

1 point

• True
• False

### Week 04

#### Practice Quiz on Micro Computed Tomography

Q1. True/False: The MicroCT is similar to a hospital CT or CAT scan in that the machine wraps around a stationary stage where the subject is sitting/laying?

• True
• False

Q2. Because x-rays can be potentially dangerous the whole MicroCT is lined with what material?

• Diamonds
• Tin
• Copper

Q3. True/False: When prepping a sample it is best to remove it from any liquids and reduce the amount of dense objects in or around the sample.

• True
• False

Q4. The cross-sectional stack of images produced after the CT scan is processed is called the:

• Projections
• 3D model
• Z-stack
• Cross-slices

#### Practice Quiz on X-ray Photoelectron Spectroscopy

Q1. During XPS, when a high-energy X-ray hits atoms on a sample surface, what does it do that ultimately leads to data collection?

• Displaces atoms’ electrons
• Breaks the atoms into pieces
• Annihilates the atoms’ electrons
• Causes atomic vibrations

Q2. XPS can be used to analyze the top ____ of a sample.

• 10 nm
• 10 mm
• 10 \muμm
• 10 cm

Q3. True/False: In XPS, the binding energies for various elements are known, which enables a user to match peaks in an XPS plot with specific elements.

• True
• False

Q4. In XPS, what information can be used to identify elements on the surface?

1 point

• Electron mass
• X-ray energy
• Electron binding energy
• X-ray velocity

Q5. Electrons in an atom with a 2+ oxidation state typically have _____ binding energies than electrons in a neutral/uncharged atom.

• Higher
• Lower

Q6. Why are gloves worn during XPS sample preparation? Select the best answer.

• To give the user better dexterity
• To keep the user’s hands warm
• To protect the sample from user contamination
• To protect the user from the sample holder’s high temperature

Q7. The X-rays used in XPS are at ______ energy.

• High
• Low

Q8. What can XPS tell us about a sample? Select all that apply

• The percentage of specific elements in the bulk
• The elements present in the bulk
• The oxidation state of elements on the surface
• What other elements surface atoms are bound to

#### Practice Quiz on Optical Spectroscopy

Q1. Which of the following can happen to light when it hits matter? (Select all that apply)

• It will be reflected
• It will be absorbed
• It will be destroyed
• It will gain energy

Q2. When preparing samples for optical spectroscopy why is the silicon surface coated with polylysine?

• To make the surface reflective, enhancing contrast
• To make the surface magnetic
• To arrange the nanoparticles in patterns
• To prevent nanoparticle aggregation

Q3. In darkfield imaging, only light that is _________ collected by the objective. (select the best answer)

• Transmitted
• Absorbed
• Scattered
• Reflected

Q4. In darkfield imaging, why do the particles of different sizes appear to be different colors? (Select the best answer)

• The particles scatter different wavelengths of light
• The particles are excited by light and emit different colors
• The particles are dyed different colors
• The particles absorb different amounts of light

#### Main : Nano Measurement and Characterization Tools: X-ray and Optical Characterization

Q1. What happens when x-rays hit a very dense part of the sample?

• They are stopped or absorbed by it
• They are reflected backward
• They pass through it

Q2. In order to stabilize a sample for scanning it may be necessary to wrap it up before placing it on the stage. What would be the best material to package a sample in before running the MicroCT?

• Fill in container with cement to hold specimen firmly
• Light plastic bottle filled with cotton
• Dense plastic tube filled with tinfoil
• Stabilize with metal wire

Q3. Which of the following can be done with the final z-stack of images produced by the MicroCT?

• It can be used to create 3D models that can be 3D printed.
• It can be measured directly using free software like ImageJ
• It can be animated to show off the internal or external structure of the specimen
• All of the above

Q4. Using XPS you can obtain information about the chemistry of your sample’s ______.

• a. bulk
• b. surface
• c. both a and b
• d. none of the above

Q5. Electrons in a neutral/uncharged atom typically have _____ binding energies than electrons in an atom with a 4+ oxidation state.

• lower
• higher

Q6. Why are tweezers used during XPS sample preparation? (Select the best answer)

• To enable better sample conductivity
• To prevent sample contamination
• To protect the user as the sample is heated
• To help thin the sample prior to analysis

Q7. On the x-axis of an XPS plot is binding energy. What does this axis represent?

• The amount of energy required to remove electrons from an atom
• The amount of energy necessary to break bonds in a molecule
• The amount of energy needed to bind two atoms together
• The X-ray energy produced by the X-ray gun

Q8. What can XPS tell us about a sample? (Select all that apply)

• The oxidation state of elements on the surface
• The surface topography
• The elements present in the bulk
• The percentage of specific elements on the surface

Q9. The way light scatters or reflects depends on the size of an object.

• True
• False

Q10. Why might taking a scattering spectrum of nanoparticles take longer than taking a spectra of a bulk material?

• Nanoparticles scatter more light that is unfocused and cannot be collected
• Nanoparticles are small and scatter less light
• Bulk materials scatter light more quickly
• Bulk materials scatter light at higher energy

Q11. As the nanoparticle size changes, the peaks in the scattering spectra shift to different wavelengths.

• True
• False

### Week 05

#### Practice Quiz on Vacuum Systems in Depth

Q1. What happens to the marshmallow when the chamber goes from vacuum to atmospheric pressure?

• It expands
• It changes color
• It stays the same size
• It collapses or contracts

Q2. In order to achieve lower pressures, a rough pump is used in combination with what?

• A high vacuum pump
• Another rough pump
• A large vacuum hose

Q3. The turbine fins on a typical turbopump spin at a rate of 400-500 revolutions per minute (rpm)

• True. A turbopump typically spins at less than 1,000 rpm.
• False. A typical turbopump spins at 50,000 rpm or more.

Q4. As a cryopump pumps down a chamber, the air molecules it pumps are ejected from the system and into the room air.

• True. A cryopump continuously ejects the pumped air molecules into the room air.
• False. Air molecules pumped by a cryopump are condensed and frozen onto internal surfaces of the cryopump.

#### Practice Quiz on Thin Film Vacuum Deposition

Q1. Thermal evaporation is an example of a PVD process. What does PVD stand for?

• Physical Vapor Deposition
• Partial Variable Desorption
• Pressurized Vapor Deposition

Q2. The melting point of tungsten is higher or lower than that of gold

1 point

• Higher
• Lower

Q3. In the e-beam evaporator, the rotating holder that holds the crucibles is called the:

• Hearth
• Substrate
• Source

Q4. When the e-beam evaporator vacuum chamber is open to room air, the valve to the high vacuum cryo-pump should be:

1 point

• closed
• open

Q5. To vent the e-beam evaporator vacuum chamber, we bleed in which gas?

• Oxygen
• Nitrogen
• Methane
• Water vapor

Q6. When finished using the e-beam evaporator, the last step is to:

• Vent the chamber and walk away
• Pump down the chamber
• Turn off the cryo-pump

Q7. The shutter is used in the sputter deposition system to:

• Control the high vacuum turbo-pump
• Control deposition of material by physically blocking sputtered material from reaching the sample
• Control the flow of nitrogen gas into the chamber

Q8. The plasma is initiated using:

• A laser
• High voltage
• A heated wire filament

#### Main : Nanofabrication: Vacuum Pumps and Thin Film Vacuum Deposition

Q1. The turbo-molecular pump, or simply turbopump, is an example of what type of pump:

• a high vacuum pump
• a low vacuum pump
• a rough pump

Q2. Why do the cooling fins in a cryopump have a large surface area?

• Larger surface area provides more room for trapping air molecules, which improves pumping.
• Large surface area reduces the noise of the pump.
• Large surface area reduces vibrations.

Q3. A cryopump will eventually become saturated with air molecules and pumping efficiency will degrade.

• True. A saturated cryopump must undergo a process called regeneration to remove trapped air molecules and regain its original pumping efficiency.
• False. A cryopump can pump indefinitely and will never become saturated with air molecules.

Q4. Why is a vacuum chamber typically kept under vacuum when not in use?

1 point

• It saves electricity
• It keeps the chamber cleaner than leaving it filled with air
• It is quieter

Q5. Why do we often use a tungsten boat to hold gold during thermal evaporation?

• Tungsten is more electrically conductive than gold
• Tungsten has a lower melting temperature than gold
• Tungsten is denser than gold
• Tungsten has a higher melting temperature than gold

Q6. It is necessary to rough pump a vacuum chamber before pumping with a high vacuum pump.

• True
• False

Q7. E-Beam evaporation heats the source material using:

• Fire
• a high voltage electron beam
• a laser

Q8. In sputter deposition, the function of the plasma is to:

• cool the target
• produce light to improve visibility in the vacuum chamber
• generate energetic atoms that remove target material
• heat the target

Q9. During sputter deposition, increasing or decreasing sputter power too quickly can cause the target material to crack.

• True
• False

### Week 06

#### Practice Quiz on Atomic Layer Deposition

Q1. What’s the main difference between Atomic Layer Deposition and Chemical Vapor Deposition? (Select One)

• In ALD, precursors are introduced one at a time.
• In CVD, precursors are introduced one at a time.
• In ALD, no substrate is needed.
• In CVD, no substrate is needed.

Q2. What is the name of a repeatable set of conditions and parameters for an Atomic Layer Deposition process?

• Optimum
• Recipe
• Experiment
• Set

#### Practice Quiz on Chemical Vapor Deposition

Q1. Atomic Layer Deposition (ALD) and Chemical Vapor Deposition (CVD) are both thin film deposition techniques

• True
• False

Q2. Which of the following statements about the difference between Physical Vapor Deposition (PVD) & Chemical Vapor Deposition (CVD) best describes is the primary difference between the two processes?

• Types of substrates treated with each process
• How the vapors are generated for the processes
• Temperature required for the processes
• Pressure required for the processes

Q3. During Chemical Vapor Deposition, distribution of gas within the chamber is completely uniform.

• True
• False

#### Practice Quiz on Plasma Enhanced Chemical Vapor Deposition

Q1. In a PECVD system, the sample to be coated is placed on the:

• Chuck
• Table
• Platen
• Stage

Q2. What is the function of the stainless steel tubing on the side of the PECVD system?

• To carry process gasses to the deposition chamber
• To carry cooling water to the deposition chamber
• To carry oil to the vacuum pump

Q3. Why do we keep the PECVD chamber pumped down when not in use?

• To keep the chamber clean
• To save electricity
• To minimize the noise in the cleanroom

#### Main : Nanofabrication: Vapor Deposition

Q1. Atomic Layer Deposition (ALD) and Chemical Vapor Deposition (CVD) are both thin film deposition techniques

• True
• False

Q2. Which of the following are properties that can be added to a substrate with a thin film?

• Electrical Properties
• Barrier Properties
• Physical Properties
• All of the above

Q3. Which of the following statements are true about the differences between Atomic Layer Deposition & Chemical Vapor Deposition.? (Check all that apply)

• CVD does not require a substrate.
• CVD processes can grow thicker films at faster rates.
• ALD can be done at lower temperatures than CVD.
• ALD films are more conformal.
• ALD takes less time than CVD.
• ALD does not involve chemical interactions.

Q4. What types of substrates can be treated with Atomic Layer Deposition?

• Glass Slides
• Silicon Wafers
• Biological Samples
• Polymers
• All of the above

Q5. What types of substrates can be treated with Chemical Layer Deposition?

• Glass Slides
• Silicon Wafers
• Biological Samples
• Polymers
• All of the above

Q6. Which of the following are properties that can be added to a substrate with a thin film?

• Electrical Properties
• Barrier Properties
• Physical Properties
• All of the above

Q7. In Chemical Vapor Deposition, like any vacuum deposition process, why are the chambers kept under vacuum even when not in use? (Please select the best answer)

• To keep contaminants from accumulating inside the chamber
• To save energy
• To prevent unauthorized use of equipment
• To comply with federal law

Q8. Solid, liquid and gas are three states of matter. PECVD utilizes a fourth state of matter called:

• vapor
• plasma
• steam

Q9. The plasma in the PECVD chamber is formed using:

• a laser
• RF (radio frequency) electrical power
• a heated wire filament

Q10. In a PECVD system, the necessary activation energy that drives the chemical processes comes from the plasma. In non-plasma CVD processes, the activation energy is provided by:

• ultrasonic agitation
• high pressure
• high temperature / heat

### Week 07

#### Practice Quiz on Photolithography

Q1. In photolithography, the glass plate containing the pattern is called the:

• Chuck
• Platen
• Source

Q2. Silicon is the most common semiconductor material used in the electronics industry.

• True
• False

Q3. How is the wafer held in place on the spin chuck during photoresist coating?

• Vacuum
• Magnets

Q4. What does “UV” stand for when discussing UV photolithography

1 point

• Under voltage
• Under vacuum
• Ultra-violet

#### Practice Quiz on Electron-beam Lithography

Q1. In the EBL system, the diameter of the focused electron beam is typically:

• Less than 5 nm
• 5 micrometers
• 5 millimeters

Q2. CAD software is used to design patterns for the EBL. What does “CAD” stand for?

• Computer Aided Design
• Computed Analog Digital
• Control And Design

Q3. The small vacuum chamber on the EBL instrument, which we place our sample into, is called the:

• Spin chuck
• Column
• Vacuum port

#### Practice Quiz on Hot Embossing

Q1. In hot embossing, all of the following are important considerations for designing a master mold, except:

• Size of the features
• Cost
• Color

Q2. Hot Embossing is used to creature features on polymers and plastics. To do this, the polymer is needs to be heated to a point where it is soft and malleable but not quite liquid. What is the name of this temperature point?

• Boiling Point
• Melting Point
• Glass Transition (Tg)
• Freezing Point

Q3. In hot embossing, we use the software to set three parameters that are critically important for the embossing process. Which of the following is not an important parameter for embossing? Select one.

• Light
• Temperature
• Time
• Force

Q4. Why is it important to blow compressed Nitrogen gas on the polymer substrate prior to loading? Select one.

• To chemically activate the surface of the substrate
• To force water vapor out of the bulk of the substrate
• To remove excess debris or contaminants on the surface of the substrate
• To cool off the substrate

#### Main : Nanofabrication: Patterning and Self-Assembly

Q1. When performing photolithography, the photoresist is intended to be a permanent or a temporary layer?

• Temporary
• Permanent

Q2. Why is there special colored lighting in the photolithography room?

• To save electricity
• To protect the light-sensitive photoresist

Q3. During photolithography, the process of illuminating the wafer with UV light is termed:

• spin coating
• exposure
• development
• baking

Q4. In photolithography, the development step comes before or after exposure?

• Before
• After

Q5. When discussing EBL, the term “EBL resist” is best described as:

• a light sensitive polymer
• a pressure sensitive polymer
• an electron sensitive polymer

Q6. When performing photolithography, we use chemical resists that are sensitive to light. When performing electron beam lithography, we use chemical resists that are sensitive to what?

• Temperature
• Electrons
• Pressure

Q7. Why must the EBL chamber be under vacuum?

• Because air would interfere with the electron beam
• Because air would degrade the polymer film on the wafer
• To reduce the noise generated by the EBL instrument

Q8. Electron beam lithography can pattern features so small that they cannot be adequately imaged using an optical microscope

• True
• False

Q9. Ion beams can be used for all of the following, except:

• Ion Implantation (Doping)
• Welding
• Patterning – Sputtering, Etching, & Milling
• Imaging

Q10. To generate a beam of positively charged Gallium ions, a ______ charged electrical field is needed to accelerate positively-charged Gallium ions. (Select one)

• positively
• neutrally
• negatively

Q11. In hot embossing, why is it important to wear gloves when handling the master mold? (Select one)

• The mold is too hot to touch when loading into the embosser
• Fingerprints and particles from hands can transfer from the mold to the substrate
• The mold is made of hazardous material

Q12. In hot embossing, a master mold is used to imprint a pattern onto a softer substrate material. The master mold is typically much more expensive than the materials it is used to emboss on.

• True
• False

Q13. There are four main steps in typical hot embossing processes. Select choice where the steps are listed in correct order.

• Demolding, Heating, Embossing, Cooling
• Cooling, Heating, Demolding, Embossing
• Embossing, Heating, Demolding, Cooling
• Heating, Embossing, Cooling, Demolding

Q14. In hot embossing, why is it important to wear gloves when handling the master mold? (Select one)

• The mold is made of hazardous material
• Fingerprints and particles from hands can transfer from the mold to the substrate
• The mold is too hot to touch when loading into the embosser

Q15. Self-assembly can only be achieved through intra-molecular forces, such as ionic and covalent bonds.

• True
• False

### Week 08

#### Practice Quiz on Chemical Wet Etching

Q1. During wet etching both sides of the substrate/wafer will be etched.

• True
• False

Q2. During wet etching, why are buffering agents added to etch solutions?

• To prevent etching of desired materials
• To maintain pH and a constant chemical reaction rate
• To make the etching solution safer
• To slow down the etching process

Q3. What wet etching parameters can be changed to affect the etch rate? Select all that apply.

• Selection of etchant type
• Gas flow rate
• Etchant concentration
• Liquid flow rate
• Mixing/stirring
• Temperature
• Pressure

Q4. The wet etching process can be performed on a lab bench.

• True
• False

Q5. During wet etching, wafers are loaded into a _______ for handling. Select the best answer

• Glass petri dish
• Rack
• Boat
• Screen

Q6. After wet etching, the wafers are rinsed with _______ and dried with ______ in the spin rinse dryer?

• Deionized water, a fiber free cloth
• Deionized water, nitrogen gas
• Ammonium fluoride, a fiber free cloth
• Ammonium fluoride, nitrogen gas

#### Practice Quiz on Dry Etching

Q1. During dry etching, the substrate/wafer is generally placed _______?

• In a chamber between two electrodes
• In a chemical etchant bath
• In a fume hood
• In a spin-rinse dryer

Q2. Plasmas contain which of the following species? Please select all that apply.

• Ionized molecules
• Atoms excited above the ground state
• Electrons
• Neutral molecules

Q3. During dry etching, only one side of the wafer will be etched.

• True
• False

Q4. In dry etching, reactive neutral species in the plasma act to remove material through __________ (select the best answer)

• chemical reaction
• physical force
• passivation

Q5. In dry etching, ions strike the surface, ________ surface atoms, and remove material. Please select the best answer.

• dislodge
• charge
• ionize
• react with

Q6. In some dry etching processes, chemical reaction products can be used to _______ surfaces, shielding them from chemical attack.

• expose
• clean
• excite
• passivate

Q7. During dry etching, ions typically arrive perpendicular to the surface. This results in a highly ________ process.

• reactive
• neutral
• directional
• selective

Q8. During dry etching, _______ are flowed into the reaction chamber to form a plasma?

• reactive gases
• organic solvents
• liquid acids
• metals

Q9. Which of the following parameters can be controlled by the user through the etching software in the “recipe”? Choose all that apply

1 point

• Power
• Chamber pressure
• Etching pattern
• Reaction temperature

Q10. What items should be placed on the chuck during dry etching? Please select all that apply.

• Cleaning cloths
• Etching bath
• Wafer/sample
• Tweezers

#### Main : Nanofabrication: Etching

Q1. In general, etching ________ material ____ a substrate. (Select the best answer)

• removes, from
• deposits, on
• protects, in
• stamps, on

Q2. What is the etch rate?

• The rate at which material is removed
• The time it takes to complete the etching process
• The rate of reaction between two materials on the substrate
• The rate at which material is deposited onto the mask

Q3. When etch selectivity is high it means:

• the etch rates of all materials in the system are equal
• the etch rates of the mask and underlying substrate are high compared to the etch rate(s) of undesired material(s)
• the etch rates of all materials in the system are high
• the etch rates of the mask and underlying substrate are low compared to the etch rate(s) of undesired material(s)

Q4. In which of the following scenarios would the etch selectivity be low? (Select all that apply)

• The etch rates of the mask and underlying substrate are low compared to the etch rate(s) of undesired material(s)
• The etch rates of all materials in the system are high
• The etch rates of all materials in the system are equal
• The etch rates of the mask and underlying substrate are high compared to the etch rate(s) of undesired material(s)
• The etch rates of all materials in the system are low

Q5. During wet etching, etching is due to

• Ion beam patterning
• a chemical reaction between the reactant/etchant and materials in the system
• a chemical reaction between the mask material and the substrate
• physical removal of material

Q6. Which of the following describes the majority of wet etching processes?

• Isotropic and selective
• Anisotropic and non-selective
• Isotropic and non-selective
• Anisotropic and selective

Q7. Which of the following are advantages of the wet etching process? (Select all that apply)

• The reactions are typically anisotropic
• The process is simple
• The chemical consumption is low
• It is easy to batch process multiple substrates/wafers
• It is easy to finely control the etch process
• The reactions are selective

Q8. Which of the following are disadvantages of the wet etching process? (Select all that apply)

• The reactions are typically isotropic
• This question refers to the following learning objective: Learners will be able to discuss the advantages and disadvantages of using chemical wet etching for an etching process.
• One of the main disadvantages of wet etching is that the reactions in most cases are isotropic. This makes etching small geometries difficult. It also requires large amounts of chemicals which can be costly to purchase and dispose of. Further, fine process control is difficult. This can make reproducibility hard.
• The process is complex
• It is difficult to batch process multiple substrates/wafers
• The chemical consumption is high
• The reactions are not selective
• It is difficult to finely control the etch process

Q9. Which of the following personal protective equipment should be worn during a standard wet etching process? (Select all that apply)

• Self-contained breathing apparatus
• Face shield
• Chemical apron
• Helmet
• Chemically resistant gloves
• Ear plugs
• Steel-toed boots

Q10. To perform the wet etch, wafers are ____________. (Select the best answer)

• placed in a vacuum chamber with reactive gases
• placed in a spin-rinse dryer and rinsed with etchant
• submerged in a bath of chemical etchant
• sprayed with chemical etchant in a fume hood

Q11. After etching, why is it important to do characterization of the wafer?

• To continue etching in places that were not etched
• To build new structures on the substrate
• To confirm and evaluate the etching process
• To clean the wafe

Q12. What can cause the etching event in dry etching?

• Chemical process
• Physical process
• All of the above

Q13. To obtain anisotropic and highly selective conditions in dry etching, ________ (Select the best answer)

• the plasma etching is followed by thin film deposition.
• chemical and physical processes can be combined.
• the plasma etching is followed by wet etching.
• the wafers are submerged in liquid nitrogen.

Q14. Which of the following are advantages of the dry etching process? (Select all that apply)

• Process can be finely controlled
• Simple equipment
• Selective and anisotropic etches possible
• Easy to etch multiple wafers
• Chemical consumption is low
• Inexpensive
• Ability to make intricate features

Q15. Which of the following are disadvantages of the dry etching process? (Select all that apply)

• Process is difficult to control
• Chemical consumption is high
• Small geometries are difficult
• Batch processing difficult
• Requires complex equipment
• Isotropic reactions
• Expensive

Q16. Which of the following parameters can be controlled by the user through the etching software in the “recipe”? (Select all that apply)

• Reaction temperature
• Etching pattern
• Chamber volume
• Power