1   NAME OF REPORTING PERSON
    S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

             State of Wisconsin Investment Board
                 39-6006423
________________________________________________________________________________
2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP *
                                                                        (a)_____
         Not Applicable                                                 (b)_____
________________________________________________________________________________
3   SEC USE ONLY

________________________________________________________________________________
4   CITIZENSHIP OR PLACE OF ORGANIZATION
           
         Madison, Wisconsin
________________________________________________________________________________
               5    SOLE VOTING POWER
  NUMBER OF                        1,867,000
   SHARES      _________________________________________________________________
BENEFICIALLY   6    SHARED VOTING POWER
  OWNED BY                         Not Applicable
    EACH                           
  REPORTING    _________________________________________________________________
   PERSON      7    SOLE DISPOSITIVE POWER
    WITH                           1,867,000
               _________________________________________________________________
               8     SHARED DISPOSITIVE POWER
                                   Not Applicable

________________________________________________________________________________
9   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                                   1,867,000
________________________________________________________________________________
10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES  CERTAIN
    SHARES *                       Not Applicable

________________________________________________________________________________
11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
                                   8.79
________________________________________________________________________________
12  TYPE OF REPORTING PERSON *

           EP (Public Pension Fund)

________________________________________________________________________________

                                                           
ITEM 1.  ISSUER
         (a)  Ultratech Stepper Inc.
         (b)  3050 Zanker Road, San Jose, CA 95134
             

ITEM 2.  PERSON FILING
         (a) State of Wisconsin Investment Board
         (b) P.O. Box 7842
             Madison, WI 53707
         (c) Wisconsin State Agency
         (d) See cover page
         (e) See cover page

ITEM 3.  THIS STATEMENT IS FILED PURSUANT TO 13d-1(b) OR 13d-2(b) AND THE STATE
         OF WISCONSIN INVESTMENT BOARD IS A GOVERNMENT AGENCY WHICH MANAGES 
         PUBLIC PENSION FUNDS SUBJECT TO PROVISIONS COMPARABLE TO ERISA.

ITEM 4. OWNERSHIP
         (a) See Row 9 on Page 2
         (b) See Row 11 on Page 2
         (c) The State of Wisconsin Investment Board retains sole voting and 
             dispositive power for all shares.