I'd like to ask about interests of Islamic banks whether its Halal?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

In general, profits of Islamic banks are Halal. These banks, as a rule, are established as Islamic substitutes in banking. Every bank has a specialized committee in Islamic economics. Its main function is to supervise bank transactions and rules in accordance with Islam. So, what is not in harmony with Islam is rejected. There is another committee to supervise all transactions achieved to determine if they are according to Islam.
No doubt that the commitment of these banks to Islam depends on knowledge, piety and executive effort of the Sharia committees.
This, for sure, differs from one bank to another. So, dealing with these banks is strongly desired if they adhere to Sharia. In other words, if you believe that these banks adhere to Islam, you should deal with them; otherwise, you deal with them if needed.
Anyway, we cannot compare Islamic banks with usury-taking-banks, that which are completely Haram as long as there are Islamic banks.
Allah knows best.