The lift-off process, while simple in concept,
becomes complex once we account for the
multiplicity of metals, polymers, and substrates
that a user is contending with. For that reason the
tool(s) to be used in the process can vary from
user to user. For most applications a hot NMP
soak, followed by hot NMP high pressure spray
with an IPA rinse to complete the process will do
the job. There are other considerations, however.
NMP is under challenge as an industrial chemical
while DMSO, a substitute, has other health
considerations especially in a semiconductor fab
setting. Some polymers are best removed by
Acetone which can simplify matters considerably.
At S-Cubed we have engineered, built and
successfully implemented tools for lift-off which
meet the specific requirements of our customers.
Some tools are multiple chamber types, some with
heated soaks, some recycling solvents etc.
Further, because the essential purpose is to
remove the underlying polymer, the same tool can
also be used as a polymer “strip” or clean tool.
