
<PAGE>
 
 
                                [FORM OF PROXY]
 
                                                                   EXHIBIT 99.3 


P R O X Y
 
                           LAM RESEARCH CORPORATION
 
                   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 LAM RESEARCH CORPORATION, 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 Roger D. Emerick and Richard H. Lovgren, 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 LAM RESEARCH CORPORATION to be held at 4650 Cushing
Parkway, Fremont, 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 PROPOSALS 3 AND 4 ON THE
REVERSE SIDE HEREOF AND WILL HAVE NO EFFECT ON PROPOSALS 1 AND 2. IF
SUBSEQUENT TO MAILING THIS PROXY CARD, THE HOLDER OF THE SHARES REPRESENTED BY
THIS PROXY WISHES TO REVOKE OR CHANGE SUCH 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  
                                                                         
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                                                    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 the issuance of shares of the Common Stock, par value $0.001 per
    share of Lam Research Corporation, a Delaware corporation ("Lam"), to the
    stockholders of OnTrak Systems, Inc., a Delaware corporation ("OnTrak"),
    pursuant to an Agreement and Plan of Merger, dated as of March 24, 1997,
    among Lam, OnTrak and Omega Acquisition Corp., a wholly-owned subsidiary of
    Lam ("Merger Sub"), providing for the merger of Merger Sub with and into
    OnTrak (the "Merger").

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

(2) To approve and adopt the Lam 1997 Stock Incentive Plan.

                 FOR  [_]       AGAINST  [_]      ABSTAIN  [_]
    
(3) To approve an amendment to the Certificate of Incorporation of Lam (the
    "Certificate") to eliminate stockholder action by written consent.

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

4) To approve an amendment to the Certificat to eliminate cumulative voting in
   the election of directors.                                                 

                 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 
 
  
