
<PAGE>
 
                                [FORM OF PROXY]
                                                                    EXHIBIT 99.6
 
P R O X Y
 
                             ONTRAK SYSTEMS, INC.
 
                   PROXY FOR SPECIAL MEETING OF STOCKHOLDERS
 
                           TO BE HELD AUGUST 5, 1997
 
          THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS
 
  The undersigned stockholder of ONTRAK SYSTEMS, INC., a Delaware corporation,
hereby acknowledges receipt of the Notice of Special Meeting of Stockholders
and Joint Proxy Statement/Prospectus, each dated July 7, 1997, and hereby
appoints James W. Bagley and Jerauld J. Cutini, and each of them, proxies and
attorneys-in-fact, with full power to each of substitution, on behalf of the
undersigned, to represent the undersigned at the Special Meeting of
Stockholders of ONTRAK SYSTEMS, INC. to be held at 1010 Rincon Circle, San
Jose, California, on August 5, 1997 at 2:00 p.m., local time, and at any
adjournment or adjournments thereof, and to vote all shares of Common Stock
that the undersigned would be entitled to vote if then and there personally
present, on all matters set forth on the reverse side hereof.
 
  THE SHARES REPRESENTED BY THIS PROXY WILL BE VOTED IN ACCORDANCE WITH THE
SPECIFICATIONS MADE HEREIN. IF NO SPECIFICATION IS INDICATED, THE SHARES
REPRESENTED BY THIS PROXY WILL BE VOTED AGAINST THE PROPOSAL ON THE REVERSE
SIDE HEREOF. IF, SUBSEQUENT TO MAILING THIS PROXY CARD, THE HOLDER OF THE
SHARES REPRESENTED BY THIS PROXY WISHES TO REVOKE OR CHANGE HOLDER'S VOTE, THE
HOLDER MAY DO SO BY PHONING 1-888-LAM-TRAK OR LOGGING ONTO THE WORLD WIDE WEB
AT HTTP://WWW.LAMRC.COM AT ANY TIME AFTER JULY 25, 1997 AND FOLLOWING THE
INSTRUCTIONS PROVIDED BY THE MESSAGES THEREON.
 
 
                                                                          SEE  
                  CONTINUED AND TO BE SIGNED ON REVERSE SIDE            REVERSE
                                                                          SIDE  
<PAGE>
 
 
                                                    Please
                                                      mark
                                                     votes   X
                                                     as in
                                                      this
                                                    example

   The undersigned acknowledges receipt of the Notice of Special Meeting and
             Joint Proxy Statement/Prospectus dated July 7, 1997.
 
Signature(s) ___________________________   Date _______________________________
NOTE: PLEASE MARK, SIGN, AND DATE AND RETURN THE PROXY CARD PROMPTLY USING THE
ENCLOSED ENVELOPE.

(1) To approve and adopt the Agreement and Plan of Merger dated March 24, 1997,
    among OnTrak Systems, Inc. ("OnTrak"), Lam Research Corporation ("Lam") and
    Omega Acquisition Corp. and the transactions contemplated thereby, pursuant
    to which OnTrak will become a wholly-owned subsidiary of Lam and each share
    of Common Stock of OnTrak will be converted into and be exchangeable for
    0.83 of a share of Common Stock of Lam, par value $0.001 per share, subject
    to adjustment.

                 FOR  [_]       AGAINST  [_]      ABSTAIN  [_]


                                Note: Please sign exactly as your name appears
                                on your stock certificate. If the stock is
                                registered in the names of two or more person,
                                each should sign. Executors, administrators,
                                trustees, guardians, attorneys and corporate
                                officers should insert their titles.
 
                                MARK HERE   
                                FOR ADDRESS 
                                CHANGE AND  
                                NOTE AT LEFT 
 
 
 
 
 
 
 
