Specific Process Knowledge/Etch/IBE⁄IBSD Ionfab 300/IBE magnetic stack etch

Results of Design of Experiments optimization of magnetic stack etching

Process parameters for the acceptance test

Parameter	Ti etch acceptance
Neutalizer current [mA]	450
RF Power [W]	800
Beam current [mA]	400
Beam voltage [V]	500
Beam accelerator voltage	500
Ar flow to neutralizer [sccm]	5.0
Ar flow to beam [sccm]	10.0
Rotation speed [rpm]	20
Stage angle [degrees]	5
Helium backside cooling [Torr]	37.5

Some SEM profile images of the etched stacks

Magnetic stack of Ta/MnIr/NiFe/Ta/Tao/Ta/MnIr/NiFe/Ta. Redeposition of etched material at photo resist. Profile ~78°	Etched magnetic stack with pool structure transfer. Chosen etch parameters result in severe footing	Etched magnetic stack with pool structure transfer. Chosen etch parameters result in severe trenching

Endpoint detection with SIMS

Magnetic stack of Ta/MnIr/NiFe/Ta/Tao/Ta/MnIr/NiFe/Ta. Redeposition of etched material at photo resist. Profile ~78°

End point detection is achieved by SIMS, and the etch rate is approximately 25 Nm/min. Resist stripping can be hard due to burned resist, to remedy this try to lover the current; this will though chance the sidewall angle. For help, discussion and further info please contact Kristian Hagsted Rasmussen.