Thin Film Deposition - Intro to Semiconductor Engineering

Name 3 important parameters to optimize for thin film deposition in a manufacturing setting.

Substrate Temperature: Controls film microstructure, adhesion, and stress.

Deposition Rate: Determines manufacturing throughput and thickness uniformity.

Chamber Pressure: Impacts the mean free path, affecting film density and step coverage.

Describe the main difference between PVD and CVD for thin film deposition.

PVD (Physical Vapor Deposition): A physical process where a solid source is vaporized and condenses on the substrate; no chemical reaction is needed to form the film.

CVD (Chemical Vapor Deposition): A chemical process where gaseous precursors react or decompose on or near the substrate surface to form the film.

Which thin film deposition method has the most direct line of sight deposition (i.e. least conformal sidewall coverage)?

Thermal Evaporation (a type of PVD). It deposits material from a localized source with minimal scattering, resulting in very poor sidewall coverage (low conformality).

Why is it important to control operating pressure for plasma sputtering?

• Because pressure controls the mean free path of the sputtered atoms. This directly affects the energy of the arriving atoms and the resulting film density and step coverage

1. What is a key advantage of using PECVD over other CVD methods?

• PECVD allows for deposition at significantly lower temperatures than conventional CVD because the plasma (not just thermal energy) drives the chemical reaction. This protects sensitive substrates.