The scoped memory is introduced during schedule phase(special memory tag), it is similar to how you tag shared memory.
See:
how VTA registers special memory scopes https://github.com/dmlc/tvm/blob/master/vta/python/vta/environment.py#L243
and how to use them in schedule https://docs.tvm.ai/vta/tutorials/vta_get_started.html#buffer-scopes