05 September 2014
There is no such periodicity. As the name suggests it is Tax Deposited by the assessee on self assessment basis. Its depisited after the end of Financial Year towards remaining tax payable after taking into account advance tax paid and TDS deducted.
Say your total tax liability comes to Rs 100. Advance Tax paid by you is Rs 80 and TDS deducted from you is Rs 10. So now you will pay Rs 10 as Self Assessment Tax. Hope its clear now.