On April 2, 2009, Zygo Corporation ("Zygo"), Electro Scientific Industries, Inc. ("ESI") and its wholly owned subsidiary, Zirkon Merger Sub, LLC ("Merger Sub") entered into a Settlement Agreement and Mutual Release (the "Settlement Agreement"), pursuant to which Zygo, ESI and Merger Sub mutually terminated the Agreement and Plan of Merger and Reorganization (the "Merger Agreement"), dated as of October 15, 2008, among them. Pursuant to the terms of the Settlement Agreement, Zygo has paid to ESI the sum of $5.4 million in full settlement of the termination fee required by the Merger Agreement. In addition, if Zygo's Board of Directors approves a third party proposal to acquire 50% or more of Zygo's common stock or substantially all of its assets within the six months after the settlement, Zygo will be required to pay an additional termination fee of $1.2 million to ESI. The Settlement Agreement also provides for a mutual release of claims arising out of or relating to the Merger Agreement.

A copy of the Settlement Agreement is attached as Exhibit 2.1.

A copy of the press release announcing the Settlement Agreement is attached as Exhibit 99.1.

(d) Exhibits

The following exhibits are filed herewith and this list is intended to constitute the exhibit index:

Exhibit Number   Exhibit Title

     2.1       Settlement Agreement and Mutual Release, dated as of April 2, 2009, by
               and among Electro Scientific Industries, Inc., Zirkon Merger Sub, LLC
               and Zygo Corporation

     99.1      Press Release, dated April 2, 2009, announcing Zygo Corporation's
               entry into the Settlement Agreement and Mutual Release and the
               termination of the Merger Agreement