LOS ANGELES, June 12, 2006 (PRIMEZONE) -- The law firm of Weiss & Lurie has filed a derivative lawsuit in Santa Clara Superior Court against certain members of KLA-Tencor Corporation's (Nasdaq:KLAC) Board of Directors, including members of its Compensation and Audit Committees, and certain of its executive officers.

Plaintiff is suing derivatively on behalf of the Company. The Complaint alleges that, in breach of their fiduciary duties, defendants regularly backdated stock options awarded to executive officers. According to the Complaint, defendants' conduct violated the Company's shareholder-approved stock option plans, the Company's corporate governance guidelines, the Company's standards of business conduct, the Company's conflicts of interest policy and industry standards. The action seeks return to the Company of all of the improperly issued backdated stock options, including any proceeds from any options that have been exercised or otherwise monetized, and other relief.

Weiss & Lurie (www.wllawca.com) is currently investigating similar stock grant practices at the following companies:

 Company                                               Ticker Symbol

 Affiliated Computer Services                          ACS
 Alkermes, Inc.                                        ALKS
 Altera                                                ALTR
 American Tower                                        AMT
 Amkor Technology, Inc.                                AMKR
 Analog Devices, Inc.                                  ADI
 Applied Micro Circuits Corp.                          AMCC
 Asyst                                                 ASYT
 Boston Communications Group Inc.                      BCGI
 Broadcom                                              BRCM
 Brocade Communications                                BRCD
 Brooks Automation                                     BRKS
 Caremark RX                                           CMX
 CNET Networks, Inc.                                   CNET
 Delta Petroleum                                       DPTR
 F5 Networks, Inc.                                     FFIV
 Fresenius                                             FMS
 HealthSouth                                           HLSH.PK
 Jabil Circuit                                         JBL
 Juniper Networks, Inc.                                JNPR
 L3  Communications Holdings                           LLL
 Linear Technology                                     LLTC
 M Systems Flash Disk Pioneers Ltd.                    FLSH
 Marvell Technology Group                              MRVL
 Maxim Integrated                                      MXIM
 McAfee                                                MFE
 Meade Instruments Corp.                               MEAD
 Medarex                                               MEDX
 Mercury Interactive                                   MERQ.PK
 Michaels Stores                                       MIK
 MicroStrategy                                         MSTR
 Millennium Pharmaceuticals                            MLNM
 Monster Worldwide                                     MNST
 Novellus                                              NVLS
 NYFIX                                                 NYFX.PK
 Openwave Systems Inc.                                 OPWV
 Power Integrations                                    POWI
 Quest Software                                        QSFT
 Rambus                                                RMBS
 Renal Care                                            RCI
 RSA Security                                          RSAS
 SafeNet                                               SFNT
 Semtech                                               SMTC
 Sepracor                                              SEPR
 Stolt-Nielsen                                         SNSA
 Sycamore Networks                                     SCMR
 Trident Microsystems                                  TRID
 Zoran                                                 ZRAN

Weiss & Lurie is also investigating claims that certain companies have granted options to executives immediately prior to announcing positive news, thereby rendering their options "in the money" without making proper disclosures of the real value of the options. The SEC maintains that where grants are made available prior to a positive announcement, a failure to discuss timing and value of the grant in SEC filings is a disclosure violation.

Weiss & Lurie, with offices in New York and Los Angeles, has extensive experience in complex litigation, particularly securities and consumer class actions, and has been appointed lead counsel in numerous class and derivative litigations.

If you are a purchaser or holder of the stock of KLA-Tencor or any of the other companies currently being investigated, please contact:

 Jordan L. Lurie, Esq.
 Leigh A. Parker , Esq.
 Weiss & Lurie -- Los Angeles
 Telephone: (800) 437-7918
 email: info@wllawca.com
 internet: www.wllawca.com

CONTACT:  Weiss & Lurie -- Los Angeles
          (800) 437-7918
          www.wllawca.com