It's the escape key on a keyboard
I'm always alone in the corner of the (usually) black/white surface,
on a top left corner of a keyboard, usually keyboards are black and white
Although sometimes people come to me at the time of exit,
escape means also exit
You have to cross 14 bridges for a vacation from me,
there is 14 keys between escape key and pause key (F1 to F12, prtscrn and scroll lock)
I'm half of my real name,
only half of escape is written on the key
And another half known as animal.
the other half is ape, which is an animal
not a fixed size figure,
I can't think of something for that one
You don't find me twice.
there is only one escape key on a keyboard