Does one owe expiation (kaffara) if he swore to wake up before 11:0 AM, and he woke up after seeing that the time had become 11:0 AM, knowing that he did not do so intentionally?

Whoever swore to wake up before eleven o'clock and woke up exactly at eleven has broken his oath and must offer expiation. His assumption that he woke up before it does not exempt him. Some jurists consider sleep to be like duress; so if the swearer woke up then was overcome by sleep and could not wake up before eleven o'clock, he is excused. However, it is more cautious to offer expiation. The one who breaks an oath is not sinful unless he intentionally breaks an oath concerning an obligatory act or refraining from a forbidden one. The expiation for an oath is feeding ten poor people or clothing them, or fasting three days for whoever cannot afford that, as Allah Almighty says: (Allah will not impose blame upon you for what is unintentional in your oaths, but He will impose blame upon you for what you intended of oaths. So its expiation is the feeding of ten poor people from the average of that which you feed your [own] families or clothing them or the freeing of a slave. But whoever cannot find [or afford it] - then a fast of three days. That is the expiation for your oaths when you have sworn. And guard your oaths. Thus does Allah make clear to you His verses that you may be grateful.)