Photolithography and Etching Techniques

This set of flashcards covers essential vocabulary and concepts in photolithography and etching techniques important for semiconductor manufacturing.

Lithography

A printing technology based on the chemical repellence of oil and water.

Photo-litho-graphy

A process that involves capturing images using a light-sensitive medium.

Positive photoresist

A type of photoresist where the exposed area is removed by the developer.

Negative photoresist

A type of photoresist where the unexposed area is removed by the developer.

Mask fabrication

The process of creating a mask that defines the areas to be patterned on a wafer.

Wafer exposure

The process of irradiating the wafer through the mask to transfer the pattern.

Resin

A binder in photoresist that provides mechanical properties like adhesion and chemical resistance.

Etch resistance

The ability of photoresist to withstand chemical etching processes.

Prebake

A process used to evaporate solvent and densify the resist after spin coating.

Post exposure bake (PEB)

A thermal process that enhances resolution by averaging the effects of exposure.

Direct etch

A pattern transfer technique where unwanted material is etched away using the photoresist as a mask.

Lift-off

A technique in pattern transfer where the unwanted material is lifted away after removing the photoresist.

Plasma etching

A dry etching method using gases to chemically and physically etch materials.

Dry etching

An etching technique that uses gas phase etchants instead of liquid solvents.

Anisotropic etching

Etching that proceeds at different rates in different directions, typically to create vertical sidewalls.

Isotropic etching

Etching that occurs uniformly in all directions, often leading to undercutting.

Electrochemical etch stop

A technique where the etch is halted by forming a passivation layer through electrochemical processes.

Deep Reactive Ion Etching (DRIE)

An advanced etching method characterized by high aspect ratios, typically >30:1.

Pellicle

A thin transparent film stretched over a mask to prevent defects caused by particles.

Excimer laser

A laser used in photolithography for producing short wavelengths necessary for fine resolution.

SIA roadmap

A guideline that drives semiconductor industry advancements in lithography and scaling of device features.

Quantum yield

The ratio of the number of photon-induced events to the number of photons absorbed.

CD

Critical dimension, the smallest feature size that can be reliably produced.

Mask to wafer alignment

The process of precisely aligning the mask over the wafer before exposure.

Mask errors

Inaccuracies in the mask that can lead to defects in the final etched pattern.

Surface roughness

A characteristic of the etched surface, affecting the performance and functionality of microstructures.