Is atheism self-contradictory ?

[Magilla]

You found them lacking in what sense ? I'll take the cosmological argument as an example, which is based on two premises :

(1) Whatever begins to exist has a cause.
(2) The Universe began to exist.

To refute the argument you need to reject one of its premises. The relationship between causes and effects is fundamental to all natural science. The second premise is based on the empirical observation that our universe is expanding. So what am I missing ? 

And if all kinds of proofs are lacking from your point of view ? What kind of proof do you require in order to accept that a divine entity exists ?

This is incorrect. Whomever makes a statement has the burden of proof. Neither (1) Whatever begins to exist has a cause, nor (2) The Universe began to exist is supported by any "proof" or evidence in the argument. A more accurate statement would be: To not accept the argument is the better option, when the premises cannot be shown to be true.

You ask: ". . . what am I missing?" What you're missing is that these premises are not answered. They may or may not be correct - we don't know for sure, (even if it looks that way with the current state of knowledge). But even if they were true, (and I'm not accepting that they are), they do not lead to the conclusion that a god exists. Who knows what the cause was, even if the premises are true?