Etching

Question 1

Which are the etching methods used in thin film patterning processes?

Answer 1

Wet - liquid etchant, chemical reaction, highly selective but isotropic
Dry - gas phase (plasma), sputtering, small feature sizes
Lift-off - chemical etch, low anisotropic, high selectivity

Question 2

Please outline the main etching process parameters. What do they depend on?

Answer 2

Etch rate - depends on sample surface, concentration, temperature, activation stimuli
Uniformity
Throughput
Directional control
Selectivity - controlled by gas formula, etch rate

Question 3

Please outline the principle of wet, dry etching and lift-off processes

Answer 3

Wet - chemical reaction
Dry - volatile compounds
Lift-off - metal deposition, solvent

Question 4

Please explain the principle of the dry etching methods used in thin film patterning processes. Outline their advantages and disadvantages

Answer 4

PE plasma etching - RF, barrel reactor, isotropic, resist ashing
RIE reactive ion etching - parallel plate reactor, electron flood gun, anisotropic
IBE ion beam etching - Ar ion beam, anisotropic, etch any material, no selectivity
ICP