One can backup archived log files using RMAN or any operating system backup utility.
Remember to delete files after backing them up to prevent the archive log directory from filling up.
If the archive log directory becomes full, your database will hang! Look at this simple RMAN
backup script:
RMAN> run {
2> allocate channel dev1 type disk;
3> backup
4> format ‘/app/oracle/arch_backup/log_t%t_s%s_p%p’
5> (archivelog all delete input);
6> release channel dev1;
7> }