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                                                                     EXHIBIT 4.1



                            LAM RESEARCH CORPORATION

                             1999 STOCK OPTION PLAN

                 AMENDED AND RESTATED EFFECTIVE OCTOBER 8, 2001



        SECTION 1 PURPOSE OF PLAN

        This 1999 Stock Option Plan (the "Plan") is adopted as of November 5,
1998 (the "Effective Date"). The purpose of the Plan is to enable Lam Research
Corporation, a Delaware corporation (the "Company"), to attract and retain
highly qualified personnel who will contribute to the Company's success by their
ability, ingenuity and industry by allowing eligible individuals to acquire or
increase proprietary interests in the Company as an incentive to remain in the
service of the Company.


        SECTION 2 DEFINITIONS

        For purposes of the Plan, the following terms shall be defined as set
forth below:

               (a) "Administrator" means the Board, or if and to the extent the
        Board does not administer the Plan, the Committee appointed by the Board
        to administer the Plan.

               (b) "Board" means the Board of Directors of the Company.

               (c) "Code" means the Internal Revenue Code of 1986, as amended
        from time to time, or any successor thereto.

               (d) "Committee" means the Stock Committee of the Board or any
        Committee the Board may subsequently appoint to administer the Plan. If
        at any time or to any extent the Board shall not administer the Plan,
        Then the functions of the Board or Administrator specified in the Plan
        shall be exercised by the Committee.

               (e) "Designated Subsidiaries" means the Subsidiaries that have
        been designated by the Board or Administrator from time to time in its
        sole discretion, whose Employees are thereon eligible to participate in
        this Plan.

               (f) "Date of Grant" means the date on which the award of a Stock
        Option is effective.

               (g) "Disability" means the inability of a Participant to perform
        substantially his or her duties and responsibilities to the Company by
        reason of a physical or mental disability or infirmity (i) for a
        continuous period of six months, or (ii) at such earlier time as the
        Participant submits medical evidence satisfactory to the Administrator
        that he or she has a physical or mental disability or infirmity which
        will likely prevent him or her from returning to the performance of his
        or her work duties for six months or longer. The date of such Disability
        shall be the date of interruption of or separation from employment with
        the Company due to such Disability or The day on which the Participant
        submits such satisfactory medical evidence establishing such Disability,
        as the case may be.

               (h) "Employee" means any person who is customarily and
        continuously employed for at least 20 hours per week by the Company or
        one of its Designated Subsidiaries. Unless the Administrator makes a
        contrary determination, the Employees of the Company shall, for all
        purposes of this Plan, be those individuals who satisfy the customary
        employment criteria set forth above and are carried as employees by the
        Company or a Designated Subsidiary for regular payroll purposes;
        provided however, that an Employee's continuous employment shall not be
        considered interrupted in the case of a leave of absence agreed to in
        writing by the Company, where such leave is for a period of not more
        than 90 days or where re-employment upon the expiration of any such
        leave is guaranteed by contract or statute.

               (i) "Fair Market Value" means, as of any given date, with respect
        to any Stock Option award granted hereunder, and at the discretion of
        the Administrator, any of the following: (i) if the Stock is publicly
        traded, the closing sale price of the Stock on such date as reported in
        the Wall Street Journal, or


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        the average of the closing price of the Stock on each day on which the
        Stock was traded over a period of up to twenty trading days immediately
        prior to such date, (ii) the fair market value of the Stock as
        determined in accordance with a method prescribed in the agreement
        evidencing any award hereunder, or (iii) the fair market value of the
        Stock as otherwise determined by the Administrator in the good faith
        exercise of its discretion.

               (j) "Parent Corporation" means any corporation (other the
        Company) in an unbroken chain of corporations ending with the Company,
        if each of the corporations in the chain (other than the Company) owns
        stock possessing 50% or more of the combined voting power of all classes
        of stock in one of the other corporations in the chain.

               (k) "Participant" means any Employee determined to be eligible to
        be awarded Stock Options under this Plan.

               (l) "Stock" means the common stock, par value $0.001 per share
        (the "Common Stock"), of the Company.

               (m) "Stock Option" means any option to purchase shares of Stock
        granted pursuant to this Plan. Each Stock Option shall be a
        non-qualified stock option which, as of the time such Stock Option is
        granted, shall not be treated as an Incentive Stock Option within the
        meaning of Section 422 of the Code.

               (n) "Subsidiary" means any corporation (other than the Company)
        in an unbroken chain of corporations beginning with the Company, if each
        of the corporations (other than the last corporation) in the unbroken
        chain owns stock possessing 50% or more of the total combined voting
        power of all classes of stock in one of the other corporations in the
        chain.


        SECTION 3 ADMINISTRATION OF PLAN

        The Administrator shall have full authority (subject to the provisions
of this Plan) to establish such rules and regulations as it deems appropriate
for the proper administration of this Plan, and to make such determinations and
interpretations concerning this Plan and Stock Options awarded under this Plan
as it deems necessary or advisable.

        In particular, the Administrator shall have the authority, consistent
with the terms of the Plan:

               (a) to select those Employees who shall be Participants;

               (b) to determine whether and to what extent Stock Options are to
        be awarded hereunder to Participants;

               (c) to determine the number of shares of Stock to be covered by
        each such Stock Option awarded hereunder, including the maximum term for
        which a Stock Option is to be outstanding;

               (d) to determine the terms and conditions of any Stock Option
        awarded hereunder; and

               (e) to determine the terms and conditions which shall govern all
        written instruments evidencing the Stock Options awarded to
        Participants.

        The Administrator shall have the authority, in its discretion, to adopt,
alter and repeal such administrative rules, guidelines and practices governing
the Plan as it shall from time to time deem advisable; to interpret the terms
and provisions of the Plan and any Stock Option awarded under the Plan (and any
agreements relating thereto); and otherwise to supervise the administration of
the Plan. All decisions made by the Administrator pursuant to the
administration, interpretation and execution of the Plan shall be final and
binding on all persons, including the Company and the Participants.


        SECTION 4 STOCK SUBJECT TO PLAN

        The total number of shares of Stock reserved and available for issuance
under the Plan shall be twenty-four million five hundred thousand (24,500,000),
subject to adjustment from time to time in accordance with this Section, or as
provided by amendment of the Board. The shares may be authorized but unissued
shares of Common Stock or reacquired shares of Common Stock, including shares
repurchased by the Company on the open market or in private purchases.


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        To the extent that (i) a Stock Option expires or is otherwise terminated
without being exercised, or (ii) any shares of Stock awarded hereunder are
forfeited, such shares shall again be available for issuance in connection with
future awards under the Plan. If any shares of Stock have been pledged as
collateral for indebtedness incurred by a Participant in connection with the
exercise of a Stock Option, and such shares are returned to the Company in
satisfaction of such indebtedness, such shares shall again be available for
issuance in connection with future awards under the Plan.

        In the event of any merger, reorganization, consolidation,
recapitalization, stock dividend or other change in corporate structure of the
Company affecting the Stock, a substitution or adjustment shall be made in (i)
the aggregate number of shares reserved for issuance under the Plan, and/or (ii)
the kind, number and class of shares and option price of shares subject to
outstanding Stock Options granted under the Plan, as may be determined by the
Administrator, in its sole discretion. Such other substitutions or adjustments
shall be made as may be determined by the Administrator, in its sole discretion.

        In connection with any event described in this paragraph, the
Administrator may provide, in its discretion, for the cancellation of any
outstanding grants and payment in cash or other property therefor. The
adjustments determined by the Administrator shall be final, binding, and
conclusive.


        SECTION 5 ELIGIBILITY

        Unless otherwise designated by the Administrator, Participants eligible
to be awarded Stock Options under the Plan include Employees whose services
contribute to the management, growth or financial success of the Company (or a
Parent Corporation or a Subsidiary), or consultants, advisors or independent
contractors who provide valuable services to the Company (or a Parent
Corporation or a Subsidiary). Any Member of the Board or member of the Company's
senior management (which specifically includes, but is not limited to, all
"officers" of the Company, as that term is intended under Rule 16(b) of the
Securities Exchange Act of 1934, as amended ("Rule 16(b)")), and any principal
stockholder otherwise an eligible Employee, consultant, advisor or independent
contractor of the Company, is not eligible to be awarded Stock Options under
this Plan.


        SECTION 6 DISCRETIONARY GRANTS OF STOCK OPTIONS

        Any Stock Option granted under the Plan shall be in such form as the
Administrator may from time to time approve, and the provisions of Stock Option
awards need not be the same with respect to each optionee. Recipients of Stock
Options shall enter into an option agreement with the Company, in such form as
the Administrator shall determine, which agreement shall set forth, among other
things, the exercise price of the option, the term of the option and provisions
regarding exercisability of the option awarded thereunder. More than one option
may be awarded to the same optionee and be outstanding concurrently hereunder.

        Stock Options awarded under the Plan shall be subject to the following
terms and conditions and shall contain such additional terms and conditions, not
inconsistent with the terms of the Plan, as the Administrator shall deem
desirable:

               (a) Option Price. The option price per share of Stock purchasable
        under a Stock Option shall be determined by the Administrator in its
        sole discretion as of the Date of Grant but shall not be less than 100%
        of the Fair Market Value of the Stock on such date.

               (b) Option Term. The term of each Stock Option shall be fixed by
        the Administrator, but no Stock Option shall be exercisable more than
        ten years after the date such Stock Option is granted.

               (c) Exercisability. Stock Options shall be exercisable at such
        time or times and subject to such terms and conditions as shall be
        determined by the Administrator at or after grant. The Administrator may
        provide, in its discretion, that any Stock Option shall be exercisable
        only in installments, and the Administrator may waive such installment
        exercise provisions at any time in whole or in part based on such
        factors as the Administrator may determine, in its sole discretion,
        including, but not limited to, in connection with any "change in
        control" of the Company, as defined in any stock option agreement or
        otherwise.

               (d) Method of Exercise. Subject to Section 6(c), above, Stock
        Options may be exercised in whole or in part at any time during the
        option period, by giving written notice of exercise to the Company


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        specifying the number of shares to be purchased, accompanied by payment
        in full of the option exercise price, as provided below or as otherwise
        determined by the Administrator. As determined by the Administrator, in
        its sole discretion, payment in whole or in part may also be made by
        means of any cashless exercise procedure approved by the Administrator.
        An optionee shall generally have the rights to dividends and any other
        rights of a stockholder with respect to the Stock subject to the Stock
        Option, including the right to vote any such Stock, only after the
        optionee has given written notice of exercise, has paid in full for such
        shares, and, if requested, has given the representation described in
        paragraph (a) of Section 9, below. The option exercise price shall be
        immediately due upon exercise of the Stock Option and shall be payable
        in one or a combination of the following forms:

                      (i) cash or check payable to the Company drawn on good and
               sufficient funds;

                      (ii) shares of Common Stock held by the optionee for the
               period necessary to avoid a charge to purposes and valued at Fair
               Market Value on the exercise date; or

                      (iii) a broker-dealer sale-and-remittance procedure
               pursuant to which the optionee shall provide irrevocable written
               instructions (x) to a designated brokerage firm to effect the
               immediate sale of the option shares and remit to the Company,
               from the sale proceeds available on the settlement date,
               sufficient funds to cover the aggregate option exercise price,
               plus all income and employment taxes required to be withheld by
               the Company in connection with the exercise and (y) to the
               Company to deliver the certificates for the purchased shares
               directly to the brokerage firm to complete the transaction.

               (e) Re-Pricing of Options. The Administrator may require the
        voluntary surrender of all or a portion of any Stock Option granted
        under the Plan as a condition precedent to the award of a new Stock
        Option. Subject to the provisions of the Plan, such new Stock Option
        shall be exercisable at the price, during such period and on such other
        terms and conditions as are specified by the Administrator at the time
        the new Stock Option is granted. Upon their surrender, Stock Options
        shall be canceled and the shares previously subject to such canceled
        Stock Options shall again be available for awards of Stock Options and
        other awards hereunder.

               (f) Loans. The Company may make loans available to Stock Option
        holders in connection with the exercise of outstanding options granted
        under the Plan, as the Administrator, in its discretion, may determine.
        Such loans shall

                      (i) be evidenced by promissory notes entered into by the
               Stock Option holders in favor of the Company,

                      (ii) be subject to the terms and conditions set forth in
               this Section and such other terms and conditions, not
               inconsistent with the Plan, as the Administrator shall determine,

                      (iii) bear interest, if any, at such rate as the
               Administrator shall determine, and

                      (iv) be subject to Board approval (or to approval by the
               Administrator to the extent the Board may delegate such
               authority). In no event may the principal amount of any such loan
               exceed the sum of (x) the exercise price less the par value (if
               any) of the shares of Stock covered by the Stock Option, or
               portion thereof, exercised by the holder, and (y) any Federal,
               state, and local income tax attributable to such exercise.

               The initial term of the loan, the schedule of payments of
        principal and interest under the loan, the extent to which the loan is
        to be with or without recourse against the holder with respect to
        principal or interest and the conditions upon which the loan will become
        payable in the event of the holder's termination of employment shall be
        determined by the Administrator. Unless the Administrator determines
        otherwise, when a loan is made, shares of Stock having a Fair Market
        Value at least equal to the principal amount of the loan shall be
        pledged by the holder to the Company as security for payment of the
        unpaid balance of the loan, and such pledge shall be evidenced by a
        pledge agreement, the terms of which shall be determined by the
        Administrator, in its discretion; provided, however, that each loan
        shall comply with all applicable laws, regulations and rules of the
        Board of Governors of the Federal Reserve System and any other
        governmental agency having jurisdiction.

               (g) Non-Transferability of Options. Unless otherwise provided
        herein or as otherwise determined by the Administrator, no Stock Option
        shall be transferable by the optionee, and all Stock Options shall be
        exercisable, during the optionee's lifetime, only by the optionee.

               (h) Termination of Employment or Service. If an optionee's
        employment with or service as an Employee, consultant, advisor or
        independent contractor to the Company terminates by reason of death,


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        Disability or for any other reason, the Stock Option may thereafter be
        exercised as provided below, or as otherwise provided in the applicable
        award agreement or determined by the Administrator. If an optionee's
        employment with or service to the Company is terminated:

                      (i) for or without cause (and whether termination is
               voluntary or involuntary), each then-outstanding unexercised
               Stock Option vested and held by the optionee as of the
               termination date shall expire within ninety (90) days of such
               termination or as otherwise determined by the Administrator on
               the date such Stock Option was granted;

                      (ii) by reason of Disability, each then-outstanding
               unexercised Stock Option vested and held by the optionee as of
               the termination date shall expire within six (6) months of such
               termination date; and

                      (iii) by reason of the optionee's death during employment,
               or if the optionee dies during the three (3) month period after
               termination of his or her employment (or such other shorter
               period of time as may be determined by the Administrator), where
               such termination is other than for cause or by reason of
               Disability, each then-outstanding unexercised Stock Option vested
               and held by the optionee as of the termination date shall expire
               within six (6) months of such termination date. After the
               optionee's death, the Stock Option may be exercised by the
               personal representative of the optionee's estate or by the
               person(s) to whom the option is transferred pursuant to the
               optionee's will or in accordance with the laws of descent and
               distribution.

               Following termination of the optionee's employment or service, a
        Stock Option shall not be exercisable to any greater extent than on the
        termination date; provided, however, that the Administrator shall have
        complete discretion, at any time while the Stock Option remains
        outstanding, to permit the Stock Option to be exercised, not only with
        respect to the number of shares for which the Stock Option is
        exercisable at the time of the termination, but also with respect to one
        or more subsequent installments of purchasable shares for which the
        Stock Option would otherwise have become exercisable had termination not
        occurred.


        SECTION 7 AMENDMENT AND TERMINATION OF PLAN

        The Board may amend, alter or discontinue the Plan, but no amendment,
alteration, or discontinuation shall be made that would impair the rights of a
Participant under any Stock Option theretofore awarded without such
Participant's consent. The Administrator may amend the terms of any Stock Option
theretofore awarded, prospectively or retroactively, but, as herein provided, no
such amendment shall impair the rights of any Participant without his or her
consent.


        SECTION 8 GENERAL PROVISIONS

               (a) The Administrator may require each person purchasing shares
        pursuant to the exercise of a Stock Option to represent to and agree
        with the Company in writing that such person is acquiring the shares
        without a view to distribution thereof. The certificates for such shares
        may include any legend which the Administrator deems appropriate to
        reflect any restrictions on transfer.

               (b) All certificates for shares of Stock delivered under the Plan
        shall be subject to such stock-transfer orders and other restrictions as
        the Administrator may deem advisable under the rules, regulations, and
        other requirements of the Securities and Exchange Commission ("SEC"),
        any stock exchange upon which the Stock is then listed, and any
        applicable Federal or state securities law, and the Administrator may
        cause a legend or legends to be placed on any such certificates to make
        appropriate reference to such restrictions.

               (c) Nothing contained in the Plan shall prevent the Board from
        adopting other or additional compensation arrangements, subject to
        stockholder approval if such approval is required; and such arrangements
        may be either generally applicable or applicable only in specific cases.

               (d) Each Participant shall, no later than the date as of which
        the value of a stock option exercise first becomes includable in the
        gross income of the Participant for Federal income tax purposes, pay to
        the Company, or make arrangements satisfactory to the Administrator
        regarding payment of, any Federal, state,


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        or local taxes of any kind required by law (as determined by the
        Administrator, in its sole discretion) to be withheld with respect to
        the award. The obligations of the Company under the Plan shall be
        conditional on the making of such payments or arrangements, and the
        Company shall, to the extent permitted by law, have the right to deduct
        any such taxes from any payment of any kind otherwise due to the
        Participant.


        SECTION 9 NON-LIABILITY

        No member of the Board or the Administrator, nor any officer or employee
of the Company acting on behalf of the Board or the Administrator, shall be
personally liable for any action, determination, or interpretation taken or made
in good faith with respect to the Plan, and all members of the Board or the
Administrator and each and any officer or employee of the Company acting on
their behalf shall, to the extent permitted by law, be fully indemnified and
protected by the Company in respect of any such action, determination or
interpretation.


        SECTION 10 TERM OF PLAN

        No Stock Option award shall be awarded pursuant to the Plan on or after
the tenth anniversary of the Effective Date, but awards theretofore awarded may
extend and be exercisable beyond that date.


        SECTION 11 CORPORATE TRANSACTIONS/CHANGES OF CONTROL

               (a) In the event of any of the following stockholder-approved
        transactions (a "Corporate Transaction"):

                      (i) a merger or consolidation in which the Company is not
               the surviving entity, except for a transaction whose principal
               purpose is to change the State of the Company's incorporation,

                      (ii) the sale, transfer, or other disposition of all or
               substantially all of the assets of the Company in liquidation or
               dissolution, or

                      (iii) any "reverse" merger in which the Company is the
               surviving entity but in which securities possessing more than 50%
               of the total combined voting power of the Company's outstanding
               securities are transferred to holders other than those who owned
               such voting power immediately before the merger,

               then immediately before the effective date of the Corporate
        Transaction, each Stock Option granted under this Plan shall become
        fully exercisable ("accelerate") with respect to the total number of
        shares of Common Stock then subject to the Stock Option. However, a
        Stock Option shall not accelerate if and to the extent:

                      (i) the Stock Option is, in connection with the Corporate
               Transaction, either to be assumed by the successor corporation or
               parent thereof or to be replaced by an option on equivalent terms
               to purchase shares of the capital stock of the successor
               corporation or parent thereof, or

                      (ii) acceleration of the Stock Option is subject to other
               limitations imposed by the Administrator at the Date of Grant.
               The determination of equivalence under clause (i) above shall be
               made by the Administrator and shall be final, binding, and
               conclusive as to all parties.

               (b) Upon consummation of the Corporate Transaction, all Stock
        Options granted under this Plan shall terminate and cease to be
        outstanding, except to the extent assumed by the successor (or
        surviving) corporation or its parent company.

               (c) Each Stock Option granted under this Plan that is replaced by
        an equivalent option in a Corporate Transaction or that otherwise
        continues in effect shall be appropriately adjusted, immediately after
        the Corporate Transaction, to apply to the number and class of
        securities that would have been issued in the Corporate Transaction to
        an actual holder of the number of shares of Common Stock that were
        subject to the Stock Option immediately before the Corporate
        Transaction. Appropriate adjustment shall also be made to the Option
        Price payable per share; provided that the aggregate Option Price
        payable for


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        such securities shall remain the same. In addition, the class and number
        of securities available for issuance under this Plan following the
        consummation of the Corporate Transaction shall be appropriately
        adjusted.

               (d) The Administrator shall have full discretionary authority,
        exercisable either in advance of, or at the time of, a Change in
        Control, to provide for the automatic acceleration of Stock Options
        granted under this Plan upon the occurrence of the Change in Control.
        The Administrator shall also have full discretionary authority to
        condition any such acceleration upon the subsequent termination of the
        optionee's service to the Company (or a parent or subsidiary) within a
        specified period after the Change in Control. Any Stock Option
        accelerated in connection with the Change in Control shall remain fully
        exercisable until the expiration of the option term. For all purposes of
        this Plan, a Change in Control shall mean a change in control of the
        Company of a nature that would be required to be reported in response to
        Item 6(e) of Schedule 14A of Regulation 14A promulgated under the
        Securities Exchange Act of 1934, as amended (the "Exchange Act"),
        whether or not the Company is then subject to such reporting
        requirement, other than a Corporate Transaction; provided that, without
        limitation, a Change in Control shall be deemed to have occurred if:

                      (i) any individual, partnership, firm, corporation,
               association, trust, unincorporated organization or other entity,
               or any syndicate or group deemed to be a "person" under Section
               14(d) (2) of the Exchange Act, is or becomes the "beneficial
               owner" (as defined in Rule 13d-3 of the General Rules and
               Regulations under the Exchange Act), directly or indirectly, of
               securities of the Company representing 40% or more of the
               combined voting power of the Company's then-outstanding
               securities entitled to vote in the election of directors of the
               Company, pursuant to a tender or exchange offer that the Board
               does not recommend that the Company's stockholders accept; or

                      (ii) during any period of two consecutive years,
               individuals who at the beginning of such period constituted the
               Board and any new members of the Board, whose election by the
               Board or nomination for election by the Company's stockholders
               was approved by a vote of at least three-quarters of the
               directors then in office who either were directors at the
               beginning of the period or whose election or nomination for
               election was previously so approved, cease for any reason to
               constitute a majority thereof.

               (e) The grant of Stock Options under this Plan shall not affect
        the right of the Company to adjust, reclassify, reorganize, or otherwise
        change its capital or business structure or to merge, consolidate,
        dissolve, liquidate, or sell or transfer all or any part of its business
        or assets.


        SECTION 12 MISCELLANEOUS

               (a) Use of Proceeds. Any cash proceeds received by the Company
        from the sale of shares pursuant to Stock Options granted under this
        Plan may be used for general corporate purposes.

               (b) Regulatory Approvals. The implementation of this Plan, the
        awarding of any Stock Option hereunder, and the issuance of Stock upon
        the exercise or surrender of any such Stock Option shall be subject to
        and conditional upon the procurement by the Company of all approvals and
        permits required by regulatory authorities having jurisdiction over this
        Plan, Stock Options granted under it, and Stock issued pursuant to it.

               (c) Securities Laws. No shares of Common Stock or other assets
        shall be issued or delivered under this Plan unless and until there
        shall have been compliance with all applicable requirements of federal
        and state securities laws, including the filing and effectiveness of a
        Form S-8 registration statement for the shares of Common Stock issuable
        under this Plan, and all applicable listing requirements of any
        securities exchange on which stock of the same class is then listed.

               (d) No Employment Rights. Neither the action of the Company in
        establishing this Plan, nor any action taken by the Administrator
        hereunder, nor any provision of this Plan, shall be construed so as to
        grant or offer any individual the right to remain in the employ or
        service of the Company (or any parent or subsidiary corporation) for any
        period, and the Company (or any parent or subsidiary corporation
        retaining the services of such individual) may terminate such
        individual's employment or service at any time and for any reason, with
        or without cause.

               (e) Assignment. Except as otherwise provided in this Plan, the
        right to acquire Common Stock or other assets under this Plan may not
        be assigned, encumbered, or otherwise transferred by any optionee.


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               (f) Governing Law. The provisions of this Plan shall be governed
        by the laws of the State of California, as such laws are applied to
        contracts entered into and performed in that State. The provisions of
        this Plan shall inure to the benefit of, and be binding upon, the
        Company and its successors or assigns, and the optionees, the legal
        representatives of their respective estates, their respective heirs or
        legatees, and their permitted assignees.