"Higher power" is an Alcoholics Anonymous thing, which has been rationalized by the group to include atheism and agnosticism, although not all atheists and agnostics are on board with that (Cf. Secular Organizations for Sobriety, Rational Recovery). In Freemasonry, you're looking for the "Supreme Being," the God of "that religion in which all men agree" which is an attempt at universalism from a 18th century cultural Christian perspective. While that concept has been harmonized with Buddhism, Hinduism, various Neopaganisms, and many other religions that aren't a natural fit, atheism remains explicitly called out as something that's incompatible in the ritual used in the Anglo-American Masonic tradition. Adogmatic or Liberal Freemasonry admits atheists (and sometimes women!), but they're much fewer in number outside Latin America and Continental Europe and unrecognized by the larger Anglo-American faction.

Masons require a belief in a supreme being and scripture, and various things online say they've explicitly forbidden atheists before. I take everything I read about Freemasonry with a grain of salt, but it still seems fairly hostile to atheists.