37 C.F.R. § 90.3 : Patents, Trademarks, and Copyrights — UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE — GENERAL PATENTS — JUDICIAL REVIEW OF PATENT TRIAL AND APPEAL BOARD DECISIONS — Time for appeal or civil action

(a) Filing deadline.
(1) For an appeal under 35 U.S.C. 141. The notice of appeal filed pursuant to 35 U.S.C. 142 must be filed with the Director of the United States Patent and Trademark Office no later than sixty-three (63) days after the date of the final Board decision. Any notice of cross-appeal is controlled by Rule 4(a)(3) of the Federal Rules of Appellate Procedure, and any other requirement imposed by the Rules of the United States Court of Appeals for the Federal Circuit.
(2) For a notice of election under 35 U.S.C. 141(d). The time for filing a notice of election under 35 U.S.C. 141(d) is governed by 35 U.S.C. 141(d).
(3) For a civil action under 35 U.S.C. 145 or146.
(i) A civil action must be commenced no later than sixty-three (63) days after the date of the final Board decision.
(ii) The time for commencing a civil action pursuant to a notice of election under 35 U.S.C. 141(d) is governed by 35 U.S.C. 141(d).
(b) Time computation.
(1) Rehearing. A timely request for rehearing will reset the time for appeal or civil action to no later than sixty-three (63) days after action on the request. Any subsequent request for rehearing from the same party in the same proceeding will not reset the time for seeking judicial review, unless the additional request is permitted by order of the Board.
(2) Holidays. If the last day for filing an appeal or civil action falls on a Federal holiday in the District of Columbia, the time is extended pursuant to 35 U.S.C. 21(b).
(c) Extension of time.
(1) The Director, or his designee, may extend the time for filing an appeal, or commencing a civil action, upon written request if:
(i) Requested before the expiration of the period for filing an appeal or commencing a civil action, and upon a showing of good cause; or
(ii) Requested after the expiration of the period for filing an appeal of commencing a civil action, and upon a showing that the failure to act was the result of excusable neglect.
(2) The request must be filed as provided in §104.2 of this title.

37 C.F.R. §90.3