Microfabrication Processes Quiz

CMP Advantages

• CMP (chemical mechanical polish) is advantageous in submicron technologies due to its ability to planarize surfaces, remove defects, and enable shallow trench isolation.
• CMP provides a high degree of planarization, reducing the topography of the wafer and enabling the fabrication of multiple layers.

Dry Etch Mechanism

• Dry etch is a process that uses plasma to create reactive species that react with the substrate material to be etched.
• Mean free path is calculated by considering the pressure, temperature, and collision cross-section of the gas molecules.

PVD and CVD Requirements

• Low pressure is necessary for PVD (physical vapor deposition) and CVD (chemical vapor deposition) to reduce the collision frequency between gas molecules and the substrate, allowing for a more controlled deposition process.
• Low pressure also enables the creation of a high-quality film with minimal defects.

Role of Plasma in CVD

• Plasma plays a crucial role in CVD (chemical vapor deposition) by activating the reactant gases, creating a high-density plasma, and enhancing the chemical reactivity of the species.
• The plasma generates a high-energy environment, allowing for the deposition of high-quality films at relatively low temperatures.

Lithography and DOF

• The depth of focus (DOF) is directly proportional to the wavelength (λ) of the exposure light, with shorter wavelengths allowing for a larger DOF.
• A larger DOF enables the creation of smaller critical dimensions (CDs) and improves the overall image quality.

Chemical Amplified Photoresist

• The chemical amplified photoresist mechanism uses a catalyst to amplify the exposure, allowing for a higher sensitivity and improved image quality.
• The catalyst reacts with the exposed areas, generating a strong acid that enhances the solubility of the resist, enabling the creation of high-aspect-ratio patterns.

Step Coverage

• Step coverage refers to the ability of a deposition technique to cover features with varying geometries and aspect ratios.
• Challenges in step coverage include the deposition of uniform films, minimizing defects, and ensuring good adhesion.

Dry Etch vs. Wet Etch

• Dry etch is a plasma-based process that uses reactive species to etch the substrate, offering a high degree of anisotropy and control.
• Wet etch is a chemical-based process that uses a liquid etchant to etch the substrate, offering a higher etch rate but lower anisotropy.

Inline and End of Line Measurements

• Inline measurements include monitoring the fabrication process in real-time, ensuring that the device is meeting the design specifications.
• End of line measurements involve testing the final device to ensure that it meets the required specifications and will last for the specified lifetime.

Analytical Methods for Troubleshooting

• Analytical methods used in semiconductor processing for troubleshooting include SEM (scanning electron microscopy), TEM (transmission electron microscopy), AFM (atomic force microscopy), and XPS (X-ray photoelectron spectroscopy).
• These methods enable the detection and characterization of defects, impurities, and contaminants, allowing for the identification and correction of process issues.

Test your knowledge on various microfabrication processes such as CMP, dry etch, PVD, CVD, and lithography. Explore the advantages of CMP, mechanisms of dry etch, importance of low pressure in thin layer deposition, role of plasma in CVD processes, and more.