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Questions and Answers
What was the primary function of IBM's millipede memory device?
What was the primary function of IBM's millipede memory device?
What technique allows for the manipulation of individual atoms or molecules?
What technique allows for the manipulation of individual atoms or molecules?
What phenomenon is observed when iron atoms are arranged into a circular 'corral' on a copper surface?
What phenomenon is observed when iron atoms are arranged into a circular 'corral' on a copper surface?
In what year did IBM first demonstrate atomic manipulation using a scanning tunneling microscope?
In what year did IBM first demonstrate atomic manipulation using a scanning tunneling microscope?
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What was a significant challenge faced by IBM's millipede memory device in reaching the market?
What was a significant challenge faced by IBM's millipede memory device in reaching the market?
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What effect does the tunneling of electrons depend on during atomic manipulation?
What effect does the tunneling of electrons depend on during atomic manipulation?
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What is a key advantage of electron beam lithography over photolithography?
What is a key advantage of electron beam lithography over photolithography?
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Which of the following describes the primary function of photolithography?
Which of the following describes the primary function of photolithography?
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What type of approach does nanolithography encompass?
What type of approach does nanolithography encompass?
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What is the main purpose of layering different materials during the photolithography process?
What is the main purpose of layering different materials during the photolithography process?
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Which step in photolithography involves the removal of unprotected material?
Which step in photolithography involves the removal of unprotected material?
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What is the primary limitation in photolithography that electron beam lithography helps to overcome?
What is the primary limitation in photolithography that electron beam lithography helps to overcome?
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Which of the following is not a step in the photolithography process?
Which of the following is not a step in the photolithography process?
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What is a critical environmental condition required during the photolithography technique?
What is a critical environmental condition required during the photolithography technique?
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Which materials are primarily involved in the photolithography process?
Which materials are primarily involved in the photolithography process?
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Which lithography technique utilizes a thermoplastic resist to create patterns through heat curing?
Which lithography technique utilizes a thermoplastic resist to create patterns through heat curing?
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Which factor primarily limits Electron Beam Lithography (EBL) in terms of speed?
Which factor primarily limits Electron Beam Lithography (EBL) in terms of speed?
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What characteristic is NOT typically associated with Self-Assembled Monolayers (SAMs)?
What characteristic is NOT typically associated with Self-Assembled Monolayers (SAMs)?
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Which technique combines top-down and bottom-up approaches for nanofabrication?
Which technique combines top-down and bottom-up approaches for nanofabrication?
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What is a significant disadvantage related to Scanning Probe Lithography (SPL)?
What is a significant disadvantage related to Scanning Probe Lithography (SPL)?
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How do the near-field scanning optical microscope (NSOM/SNOM) techniques bypass the diffraction limit?
How do the near-field scanning optical microscope (NSOM/SNOM) techniques bypass the diffraction limit?
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Which of the following techniques involves physically removing molecules from a surface using an AFM tip?
Which of the following techniques involves physically removing molecules from a surface using an AFM tip?
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What is a common method used in Dip-Pen Nanolithography (DPN) to deliver molecules onto a surface?
What is a common method used in Dip-Pen Nanolithography (DPN) to deliver molecules onto a surface?
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In what environment can Scanning Probe Lithography (SPL) be conducted?
In what environment can Scanning Probe Lithography (SPL) be conducted?
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What is a requirement for tips used in Near-field Scanning Optical Microscopes to achieve high resolution?
What is a requirement for tips used in Near-field Scanning Optical Microscopes to achieve high resolution?
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Study Notes
Scanning Probe Lithography (SPL)
- SPL uses scanning probe microscopy principles to selectively modify surfaces.
- Enables the creation of intricate nanoscale patterns.
Nanolithography Techniques
- Top-down (subtractive): Removes material to form desired structures (e.g., photolithography, electron beam lithography, nanoimprint lithography).
- Bottom-up (additive): Assembles atoms/molecules to build structures (e.g., self-assembly).
Photolithography
- Uses light to selectively modify surfaces, primarily used for integrated circuit production.
- Feature sizes down to 5 nm are commercially possible.
- Requires masks, photoresists, and UV light.
- Top-down approach.
- Process steps: substrate coating, photoresist layer, UV exposure with a mask, washing, etching unwanted material, photoresist removal.
Electron Beam Lithography (EBL)
- Replicates photolithography, uses electrons instead of photons.
- Feature sizes down to 2 nm achievable, but 20 nm is more common.
- No mask required, as the electron beam can be scanned precisely.
- Electron-sensitive resist used.
- Slower than photolithography.
- Needs a vacuum.
- Top-down approach.
Nanoimprint Lithography (NIL)
- Uses a mold/stamp to transfer a pattern, quick and cost-effective (potentially).
- Method 1: Thermoplastic resist fills mold gaps and hardens.
- Method 2: Self-assembling molecules in solution act as a "stamp."
- High throughput, 10 nm resolution achievable, but mold production requires a separate process.
- Top-down (Method 1) or template-assisted bottom-up(Method 2) approach.
Self-Assembled Monolayers (SAMs)
- SAMs are spontaneous molecular assemblies on substrates.
- Different functional groups (headgroups) have specific affinities for different substrate materials. (eg. thiols on metals, carboxylic acids on metal oxides)
- Changing the headgroup changes surface properties.
- Bottom-up approach.
Dip-Pen Nanolithography (DPN)
- Uses surface tension & SAMs to "write" patterns on surfaces, using an AFM tip.
- Tip moves across surface applying SAMs in specific locations.
- Controlled by position of tip (AFM)
- Uses a reservoir of SAM materials
- Top-down approach.
Near-field Scanning Optical Microscopy (NSOM/SNOM)
- Utilizes light, surpasses diffraction limit through near-field evanescent waves.
- Top-down approach.
- Creates patterns via light interactions.
- Tip aperture defines resolution.
- Light source and detectors place the light very close to the sample.
Nanoshaving/Scratching
- Uses controlled AFM tip pressure to physically remove molecules from a surface.
Comparison of SPL Techniques (advantages/disadvantages)
- Advantages (SPL): High resolution, versatility, single-step process, direct-write capability, potential for various environments (air, liquid).
- Disadvantage (SPL): typically slow process, limited throughput
Parallel SPL
- Exploits arrays of probes for parallel processing to increase throughput.
Atomic Manipulation
- Uses a scanning tunneling microscope to pick up and move atoms/molecules on a surface.
- Example: creating a corral using iron atoms on copper.
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Description
Explore the essential techniques of nanolithography including Scanning Probe Lithography, Photolithography, and Electron Beam Lithography. Understand the differences between top-down and bottom-up methods, along with their applications in modern manufacturing. This quiz will help reinforce your knowledge of nanoscale patterning.
