Aqueous fluoride compositions for cleaning semiconductor devices
The present invention relates to dilute fluoride solutions and methods for cleaning plasma etch residue from semiconductor substrates including such dilute solutions. The compositions and methods according to the invention can advantageously provide both cleaning efficiency and material compatibility.
1. A method of cleaning a semiconductor substrate comprising
providing a semiconductor substrate comprising a low-K substrate with un-ashed resist or incompletely ashed resist residue thereon;
providing a dilute aqueous cleaner and residue remover comprising:
from 0.02% to 0.18% by weight of a fluoride-containing compound selected from the group consisting of ammonium fluoride, alkylammonium fluorides, ethanolamine fluoride, ammonium biflouride, alkylammonium bifluorides, or a mixture thereof;
from 20% to about 40% by weight water;
from 59% to 85% by weight total of an amide and an ether solvent,
from 0.2% to 5% by weight of an inorganic acid selected from sulfamic acid, phosphonic acid, or mixture thereof; and
from 0.2% to 5% by weight of an alkanolamine; wherein said cleaner and residue remover is free of chelators; and
contacting the semiconductor substrate with the aqueous cleaner and residue remover for a period and under a temperature sufficient to clean the substrate of said resist and/or incompletely ashed resist residue.
2. The method of claim 1 further comprising rinsing the substrate after cleaning, and drying the substrate, wherein the dielectric constant of the low-k substrate after drying is within 0.002 of the dielectric constant before cleaning.
3. A method of cleaning a semiconductor substrate comprising
providing a semiconductor substrate comprising a low-K substrate having copper metal thereon and plasma-ashed residue thereon;
providing a dilute aqueous cleaner and residue remover comprising:
between 0.5% and 1% of ammonium bifluoride, ammonium fluoride, or mixture thereof, between about 55 and 75% of one or more amide solvents;
water; and
one or more alkanolamines in an amount sufficient to have a pH of between 8.0 and 8.2, wherein said cleaner and remover is free of chelating agents; and
contacting the semiconductor substrate with the aqueous cleaner and residue remover for a time and at a temperature sufficient to clean the substrate of residue.
4. The method of claim 3 further comprising rinsing the substrate after cleaning, and drying the substrate, wherein the dielectric constant of the low-k substrate is within 0.002 of the dielectric constant before cleaning.