Is there a time frame for contesting a will? I just found out a man that has been deceased for 20yrs. Is my biological father.

Yes, there is a time limit for contesting a Will.  In most states, it is three years.  Contesting a Will means that you are challenging the validity of a Will, and that's probably not what you want to do.  But estates generally have this time limit so that there is some finality rather than people having to give back inheritances years after receiving them.  It would be worth checking to see whether your father's estate was distributed.  If his Will was probated, the information is public and available at the probate court for the county where he lived at the time of his death.  There also may be a trust, which is not probated, so it would be worth finding out whether that is the case.  Trusts are private so can be difficult to get access to, but a probate attorney may be able to assist you in that regard or you can try contacting your father's heirs, if you know them.  Good luck.