Title: Summary: Nanofabrication

Choose the correct statement.

- Nanofabrication is a specialized area of manufacturing which uses specialized techniques to chemically, optically, and mechanically pattern materials in order to create small devices. (correct)
- Nanofabrication is not a specialized are of manufacturing and simply uses miniaturized techniques for large scale manufacturing.
- Nanofabrication describes a special type of type of ultra-clean and high material purity manufacturing that spans many lengthscales.

- Photolithography is a light-based technique which transfers patterns to a photoresist by selectively exposing certain areas of the photoresist to a specific type of light such as UV light. Patterns can be exact or inverse images of the mask based on how the photoresist changes solubility when interacting with light. (correct)
- Photolithography is an electron-based technique which transfers patterns to a photoresist by scanning an electron beam over specific areas of the photoresist. It is well suited for patterning large areas quickly but can only remove photoresist through electron beam exposure.

- Positive tone resist leads to a copy of the mask transferred into the photoresist. This means exposed areas become lose photoresist and the substrate is accessible. Negative tone resist creates an inverse image of the mask. This means photoresist only remains in the exposed areas and the substrate is accessibly in the areas that were previously masked. (correct)
- Negative tone resist leads to a copy of the mask transferred into the photoresist. This means exposed areas become lose photoresist and the substrate is accessible. Positive tone resist creates an inverse image of the mask. This means photoresist only remains in the exposed areas and the substrate is accessibly in the areas that were previously masked.

- Photolithography is limited in resolution by the light source but can pattern a large area very quickly. E-beam lithography can write smaller pattern features than photolithography but since it rasters the beam, more time is necessary to complete a pattern. Both techniques can use either positive or negative tone resist. (correct)
- Photolithography is not limited in resolution by the light source but can only be used with negative tone resists. E-beam lithography resolution is limited by the size of the focused electron beam and can only be used with positive tone resists.

- Etching is a process for removing material through a chemical process. Wet etching refers to solution based chemistries and dry etching refers to plasma or gas-phase chemistries. (correct)
- Etching is a process for removing material through a mechanical process. It primarily involves ablating the surface through scratching or controlled formation of grooves.
- Etching is a process for removing material but there is limited control over the rate of material removal or shape of the cavity formed during the material removal.

- Wet etching and dry etching can be isotropic or anisotropic depending on the chemistry interaction with the substrate. Dry etching is typically fall more anisotropic or directed due to the passivation layer processing which promotes most of the etching on the base and not the sidewalls of the channel. (correct)
- Wet etching can be isotropic or anisotropic depending on the chemistry interaction with the substrate. Dry etching is only uni-directional removing material layer by layer due to the passivation layer processing which promotes most of the etching on the base and not the sidewalls of the channel.
- Wet etching is only every isotropic and dry etching can be either isotropic and highly directional based on the processing conditions.

- Deposition and etching can be done from solution or from a gaseous state. The rate of these processes primarily depends on temperature and surface chemistry interactions. (correct)
- Deposition cannot be done from solution but only from a gaseous state, unlike etching. Material is deposited one layer at a time and the rate of deposition is limited by the cycle of each atomic layer deposition.
- Deposition can only be done from solution, unlike etching. Only metallic or conductive materials can be deposited and films can be up to 100s of microns in thickness.