Hi Dialhardeep,
Background check has nothing to do with FBI.
After interview waiver (or successful interview if one was required) processing officer initiated background/security check also - this task may take anywhere from few months to well over a year to conclude, depending from your background, activities, associations, nationality, countries you resided in and other factors.
1. Background check - verification of education and experience credentials when employers and schools may be contacted to verify authenticity of documents and truthfulness of your claims; if particular claim cannot be conclusively verified then it won't be counted.
and
2. Background/Security check - conducted completely outside of immigration by Canadian intelligence and security agencies with or without cooperation of proper authorities in countries you lived in to find out if you are or were involved in and/or associated with someone who is or was involved in activities like terrorism, espionage, organized crime, radical movements, crimes against humanity, etc