pass test wait for oath now
how long ????????

Hi Bolaian,
I notice you are on the same boat with me from Chicago DO. Although I haven't personally experienced it yet nor passing the interview yet, but I read on some posts on another forum that Chicago DO oath letter arrival seems pretty fast about 2-4weeks after you pass your interview.
Theoretically, USCIS has the official time up to 120days (4months) after interview to send any applicant the oath letter. Hope it helps.