Exhibit (a)(10)

FORM OF NOTICE OF EXPIRATION OF OFFER, AMENDMENT OR REPLACEMENT

OF ELIGIBLE OPTIONS AND COMMITMENT TO PAY CASH BONUS

To:

We are pleased to announce that we have completed our Offer to Amend or Replace Eligible Options. As a result of the Offer, we have amended outstanding Eligible Options covering              shares of KLA-Tencor common stock to increase the exercise price of each such option to the lower of (i) the fair market value per share of KLA-Tencor common stock on the actual grant date of that option or (ii) $            , the closing price per share of such common stock on the June     , 2007 amendment date. In addition, the participants whose Eligible Options have been so amended are now eligible to receive special cash bonuses in the aggregate amount of up to $             to compensate them for the higher exercise prices per share in effect for their amended options.

In addition, we canceled tendered Eligible Options covering              shares of KLA-Tencor common stock because the adjusted exercise price would have been the same or lower than the exercise price in effect for those options prior to the amendment. In replacement of each such canceled option, we immediately granted a New Option that is exactly the same, including the same exercise price per share, but with a new grant date of June     , 2007.

The chart below lists each of your tendered Eligible Options that have been amended. The information in the chart confirms that the listed Eligible Options were validly submitted for amendment pursuant to the Offer and not otherwise withdrawn prior to the expiration date of the Offer. Accordingly, the adjusted exercise price per share now in effect for each of your amended Eligible Options is indicated below. Each of your amended options will continue to vest in accordance with the same vesting schedule measured from the same vesting commencement date currently in effect for that option. The amendment has no effect on the option’s vesting schedule, exercise period, option term or any other term or provision of the option.

 

Grant Date

   Total
Number of
Shares
Subject to
Outstanding
Option
   Exercise
Price Per
Share Prior
to
Amendment
   New
Exercise
Price Per
Share
Following
Amendment
   Number of
Outstanding
Option
Shares
Subject to
Amended
Exercise
Price
   Number of
Outstanding
Option
Shares Not
Subject to
Amended
Exercise
Price
   Special
Bonus
Payable in
2008
      $      $            $  
                                   
                               Total
Special
Bonus
Amount:
                  $ _____

In exchange for your agreement to amend your outstanding Eligible Option to the Adjusted Exercise Prices determined for those options, KLA-Tencor hereby irrevocably commits to pay you a special cash bonus in the amount of $            . The applicable provisions under Section 409A of the Internal Revenue Code do not permit the cash bonus to be paid in the same year in which the Eligible Options are amended. Therefore, the cash bonus will be paid on KLA-Tencor’s first regularly scheduled payroll date following January 1, 2008, which is scheduled to be January 10, 2008. KLA-Tencor must withhold all applicable U.S. federal, state and local income and employment withholding taxes and other required payments, and you will receive only the portion of the payment remaining after


those taxes and payments have been withheld. You will receive your cash bonus even if your employment with KLA-Tencor terminates prior to the date on which the cash bonus is paid.

This commitment to pay you the special cash bonus is governed by the terms and conditions of the Offer as set forth in the Offer to Amend or Replace, the Letter of Transmittal and the Stock Option Amendment and Special Bonus Agreement (collectively, the “Offer Documents”), all of which are incorporated herein by reference. Accordingly, this commitment and the Offer Documents reflect the entire agreement between you and KLA-Tencor with respect to the amendment of your tendered Eligible Options.

Each New Option granted pursuant to you pursuant to the Offer is exactly the same as the tendered Eligible Option it replaced, including the same exercise price per share and no loss of vesting or change to the expiration date, but with a new grant date of June _, 2007. The chart below indicates which tendered Eligible Options were canceled and replaced with a New Option:

 

Grant Date of Canceled Option

   Total Number
of Shares
Subject to
New Option
   Exercise Price
Per Share
Prior to
Cancellation
   Same Exercise
Price Per
Share under
New Option
      $      $  

 

KLA-TENCOR CORPORATION
By:     
Title:     
Date: