EXHIBIT 5.1



                 OPINION OF HELLER EHRMAN WHITE & MCAULIFFE LLP


November 30, 2001


Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, D.C. 20549


Re:  Registration Statement on Form S-8


Ladies and Gentlemen:

        We have acted as counsel to Lam Research Corporation, a Delaware
corporation (the "Company"), in connection with the Registration Statement on
Form S-8 (the "Registration Statement") which the Company proposes to file with
the Securities and Exchange Commission on or about November 30, 2001 for the
purposes of registering under the Securities Act of 1933, as amended, 12,500,000
shares of its Common Stock, $0.001 par value (the "Shares"), issuable under the
Lam Research Corporation 1999 Stock Option Plan, as amended (the "Plan").

        We have assumed the authenticity of all records, documents and
instruments submitted to us as originals, the genuineness of all signatures, the
legal capacity of natural persons and the conformity to the originals of all
records, documents and instruments submitted to us as copies.

        In rendering our opinion, we have examined the following records,
documents and instruments:

        (a)    The Amended Certificate of Incorporation of the Company,
               certified by the Secretary of State of the State of Delaware as
               of November 28, 2001, and certified to us by an officer of the
               Company as being complete and in full force as of the date of
               this opinion;

        (b)    The Amended and Restated Bylaws of the Company certified to us by
               an officer of the Company as being complete and in full force and
               effect as of the date of this opinion;

        (c)    A Certificate of Good Standing relating to the Company issued by
               the Secretary of State of the State of Delaware as of November
               28, 2001;

        (d)    A Certificate of Status Foreign Corporation issued by the
               Secretary of State of the State of California as of November 28,
               2001;

        (e)    A Certificate of an officer of the Company (i) attaching records
               certified to us as constituting all records of proceedings and
               actions of the Board of Directors, including any committee
               thereof, and stockholders of the Company relating to the Shares,
               and the Registration Statement, and (ii) certifying as to certain
               factual matters;

        (f)    The Registration Statement;

        (g)    The Plan; and

        (h)    A letter from Mellon Investor Services LLC, the Company's
               transfer agent, dated November 28, 2001, as to the number of
               shares of the Company's Common Stock that were outstanding on
               November 27, 2001.

        This opinion is limited to the federal law of the United States of
America and the Delaware General Corporation Law, and we disclaim any opinion as
to the laws of any other jurisdiction. We further disclaim any opinion as to any
other statute, rule, regulation, ordinance, order or other promulgation of any
other jurisdiction or any regional or local governmental body or as to any
related judicial or administrative opinion.

        Based on the foregoing and our examination of such questions of law as
we have deemed necessary or appropriate for the purpose of this opinion, and
assuming that (i) the Registration Statement becomes and remains effective
during the period when the Shares are offered and issued, (ii) the full
consideration stated in the Plan is paid for each Share and that such
consideration in respect of each Share includes payment of cash or other lawful
consideration, (iii) appropriate certificates evidencing the Shares are executed
and delivered by the Company, and (iv) all applicable securities laws are
complied with, it is our opinion that the Shares covered by the Registration
Statement, when issued by the Company, will be validly issued, fully paid and
nonassessable.

        This opinion is rendered to you in connection with the Registration
Statement and is solely for your benefit. This opinion may not be relied upon by
you for any other purpose, or relied upon by any other person, firm, corporation
or other entity for any purpose, without our prior written consent. We disclaim
any obligation to advise you of any change of law that occurs, or any facts of
which we may become aware, after the date of this opinion.

        We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement.


                                        Very truly yours,


                                        /s/ Heller Ehrman White & McAuliffe LLP