It's too bad Google didn't see fit to honour the occasion. But I'm sure all the real Batman fans understand the significance of Finger's contribution to the franchise and will spare him a thought on his centenary.
(https://www.batman-online.com/forum/proxy.php?request=http%3A%2F%2F3.bp.blogspot.com%2F-aGVCTRrb1_k%2FUt2lo9nP2_I%2FAAAAAAAAClA%2FeZquc2zfrnw%2Fs1600%2FBill%2BFinger.png&hash=4b83245fa149a80eb9820c596e782100473f8075)
Comic Book resources have got a nice feature on ways to celebrate the occasion: http://robot6.comicbookresources.com/2014/02/five-ways-to-celebrate-bill-fingers-birthday/
A true Batman legend. The credit should be:
Batman created by Bill Finger and Bob Kane.