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                                                                  Exhibit 10.63



                             SUPPLEMENTAL AGREEMENT


                                  in respect of


             RECEIVABLES PURCHASE AGREEMENT DATED DECEMBER 26, 1997


                                     between


                             LAM RESEARCH CO., LTD.
                                    as Seller


                    BANKS AND OTHER INSTITUTIONS NAMED HEREIN
                                  as Purchasers


                        ABN AMRO BANK N.V., TOKYO BRANCH
                           as Representative Purchaser

                        ABN AMRO BANK N.V., TOKYO BRANCH
                              as Initial Purchaser

                                       and

                             LAM RESEARCH CO., LTD.
                               as Collection Agent




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THIS SUPPLEMENTAL AGREEMENT is deemed effective as of the 25th day of December,
1998

BETWEEN:

(1)     LAM RESEARCH CO., LTD., a Japanese corporation having its registered
        office at 1-1-10, Oyama, Sagamihara-shi, Kanagawa Prefecture, Japan as
        seller of receivables (in such capacity, the "SELLER");

(2)     BANKS AND OTHER INSTITUTIONS NAMED IN THE SIGNATURE PAGE HEREOF as
        purchasers (collectively, the "PURCHASERS" and each a "PURCHASER");

(3)     ABN AMRO BANK N.V. acting through its TOKYO BRANCH, a branch licensed in
        Japan and having its registered office at Shiroyama JT Mori Building,
        4-3-1, Toranomon, Minato-ku, Tokyo 105-6013, Japan, as representative of
        the Purchasers (in such capacity, the "REPRESENTATIVE PURCHASER");

(4)     ABN AMRO BANK N.V. acting through its TOKYO BRANCH, a branch licensed in
        Japan and having its registered office at Shiroyama JT Mori Building,
        4-3-1, Toranomon, Minato-ku, Tokyo 105-6013, Japan, as the Initial
        Purchaser (in such capacity, the "INITIAL PURCHASER"); and

(5)     LAM RESEARCH CO., LTD., a Japanese corporation having its registered
        office at 1-1-10, Oyama, Sagamihara-shi, Kanagawa Prefecture, Japan, as
        collection agent in relation to receivables (in such capacity, the
        "COLLECTION AGENT").

WHEREAS:

(A)     The Seller, the Initial Purchaser, the Representative Purchaser and the
        Collection Agent have entered into a Receivables Purchase Agreement
        dated December 26, 1997 (the "ORIGINAL AGREEMENT"), pursuant to which
        the Seller and the Initial Purchaser have agreed, on the terms and
        subject to the conditions thereof, that the Seller will sell to the
        Initial Purchaser certain receivables which have arisen, or will arise
        during its term, out of the sales by the Seller of certain equipment,
        and the Collection Agent has agreed, upon the terms and subject to the
        conditions thereof, to act as the agent of the Initial Purchaser in
        connection with the collection of receivables from time to time assigned
        to the Initial Purchaser in accordance with the terms thereof; and

(B)     The parties hereto wish to amend certain terms of the Original
        Agreement, to the extent provided below.

IT IS HEREBY AGREED as follows:-

1.      GENERAL

        (1) Terms defined in the Original Agreement (if applicable, as amended
by this Agreement) shall, when used in this Agreement (including in the
Recital), have the same meanings herein as therein, unless otherwise
specifically provided herein.



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                                      -2-


        (2) Except insofar as amended by this Agreement, the Original Agreement
shall continue in full force and effect and shall be read and construed as one
with this Agreement. Upon this Agreement taking effect, references in the
Original Agreement to "this Agreement", "herein", "hereunder" and other similar
expressions shall be deemed to be references to the Original Agreement to the
extent amended and restated by this Agreement.

        (3) This Agreement shall be governed by and construed in accordance with
the laws of Japan and the provisions of Clause 38 (Jurisdiction) of the Original
Agreement shall be deemed to apply to this Agreement as though they were set out
in full herein.

        (4) The headings are for convenience of reference only and shall not
affect the construction hereof.

        (5) This Agreement may be signed in any number of counterparts. Any
single counterpart or a set of counterparts signed, in either case, by all the
parties hereto shall constitute a full and original agreement for all purposes.

2.      AMENDMENT TO ORIGINAL AGREEMENT

        Subject to Clause 4 hereof, effective as of December 25, 1998 (the
"EFFECTIVE DATE"), the Original Agreement shall be amended as follows:

        (1) in Clause 1.1 of the Original Agreement, the definition of
"Applicable Margin" shall be amended in its entirety to read as follows:

        "APPLICABLE MARGIN" means (a) in the case of a Purchased Receivable
        which is a Post-Acceptance Receivable as of two (2) Business Days prior
        to the first day of the relevant Fixed Period, 1.00 percent per annum,
        and (b) in the case of a Purchased Receivable which is not a
        Post-Acceptance Receivable as of two (2) Business Days prior to the
        first day of the relevant Fixed Period, such rate per annum (expressed
        as a percentage) as shall be determined pursuant to Clause 19.9;

        (2) in Clause 1.1 of the Original Agreement, the definition of "Total
Purchase Commitments" shall be amended by replacing "Six Billion Yen
((Y)6,000,000,000)" with "Four Billion Yen ((Y)4,000,000,000)";

        (3) in Clause 1.1 of the Original Agreement, the following definitions
shall be added in their appropriate alphabetical locations:

        "AGENT" has the meaning set forth in the Loan Agreement (it being
        understood that the definition of "Agent" in the Loan Agreement shall be
        deemed to be incorporated herein as if it was fully set out herein);

        "DEFAULT" has the meaning set forth in the Loan Agreement (it being
        understood that the definition of "Default" in the Loan Agreement shall
        be deemed to be incorporated herein as if it was fully set out herein);

        "EVENT OF DEFAULT" has the meaning set forth in the Loan Agreement (it
        being understood that the definition of "Event of Default" in the Loan
        Agreement as well as Clause 11.1 (including the definitions of the
        defined terms used


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        therein) of the Loan Agreement shall be deemed to be incorporated herein
        as if it was fully set out herein);

        "FINANCIAL STATEMENT" has the meaning set forth in the Loan Guaranty (it
        being understood that the definition of "Financial Statements" and other
        defined terms used in such definition in the Loan Guaranty shall be
        deemed to be incorporated herein as if they were fully set out herein);

        "GAAP" has the meaning set forth in the Loan Guaranty (it being
        understood that the definition of "GAAP" the Loan Guaranty shall be
        deemed to be incorporated herein as if it was fully set out herein);

        "LOAN AGREEMENT" means the Loan Agreement dated as of September 30, 1998
        between Lam Research Co., Ltd. as Borrower, the banks and financial
        institutions named therein as Lenders, and ABN AMRO Bank N.V., Tokyo
        Branch as Agent;

        "LOAN GUARANTY" means the Guaranty dated as of September 30, 1998
        executed by Lam Research Corporation, as Guarantor, in favor of ABN AMRO
        Bank N.V., Tokyo Branch as Agent for the Lenders to the Loan Agreement;

        "MARGIN CERTIFICATE" means a certificate in the form of the Eleventh
        Schedule;

        "MARGIN DETERMINATION DATE" means the fifteenth day following the date
        by which the Seller is required to deliver the quarterly financial
        statements and information under subclauses (i) and (iii) of Clause
        19.9(c) (it being understood that the delivery by the Guarantor to the
        Agent of the quarterly financial statements and information required
        under clauses (i) and (iii) of Subparagraph 4(a) of the Loan Guaranty
        shall be deemed effective delivery by the Seller to the Representative
        Purchaser of the quarterly financial statements and information required
        under subclauses (i) and (iii) of Clause 19.9(c));

        "MARGIN PERIOD" means the period commencing on and including December
        27, 1999 and ending on but excluding the Margin Determination Date
        falling immediately following December 27, 1999, and thereafter each
        successive period commencing on and including the last preceding Margin
        Determination Date and ending on but excluding the next succeeding
        Margin Determination Date;

        "SENIOR INDEBTEDNESS RATIO" has the meaning set forth in the Loan
        Guaranty (it being understood that the definition of "Senior
        Indebtedness Ratio" and other defined terms used in such definition in
        the Loan Guaranty shall be deemed to be incorporated herein as if they
        were fully set out herein);

        "SUBSIDIARY" has the meaning set forth in the Loan Guaranty (it being
        understood that the definition of "Subsidiary" and other defined terms
        used in such definition in the Loan Guaranty shall be deemed to be
        incorporated herein as if it was fully set out herein);

        (4) in Clause 2.1 of the Original Agreement, "Six Billion Yen
((Y)6,000,000,000)" in the third sentence shall be replaced with "Four Billion
Yen ((Y)4,000,000,000)";




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        (5) in Clause 19 of the Original Agreement, the following clause shall
be added as Clause 19.9:

        19.9   (a)    The Applicable Margin (for the purposes of item (b) of
                      the definition thereof) shall be (i) in respect of the
                      period from and including the Initial Purchase Date to and
                      including the date immediately preceding December 25, 1998
                      (the "EFFECTIVE DATE"), 0.90 percent per annum and (ii) in
                      respect of the period from and including the Effective
                      Date to and including December 26, 1999, 1.50 percent per
                      annum.

               (b)    On or after December 27, 1999, the Applicable Margin (for
                      the purposes of item (b) of the definition thereof) shall
                      be, in respect of any Margin Period:

                      (i)    if the Guarantor does not have net profits of
                             greater than US$1, as determined in accordance with
                             generally accepted accounting principles and
                             practices in the United States of America as
                             consistently applied, during both the fiscal
                             quarter ending on September 26, 1999 and the fiscal
                             quarter ending on December 26, 1999, 1.50 percent
                             per annum;

                      (ii)   if the Guarantor has net profits of greater than
                             US$1, as determined in accordance with generally
                             accepted accounting principles and practices in the
                             United States of America as consistently applied,
                             during both the fiscal quarter ending on September
                             26, 1999 and the fiscal quarter ending on December
                             26, 1999 and the Senior Indebtedness Ratio of the
                             Guarantor as set forth in the quarterly financial
                             statements and information of the Guarantor for the
                             fiscal quarter ending immediately preceding the
                             first day of the relevant Margin Period is less
                             than 0.10, 0.75 percent per annum;

                      (iii)  if the Guarantor has net profits of greater than
                             US$1, as determined in accordance with generally
                             accepted accounting principles and practices in the
                             United States of America as consistently applied,
                             during both the fiscal quarter ending on September
                             26, 1999 and the fiscal quarter ending on December
                             26, 1999 and the Senior Indebtedness Ratio of the
                             Guarantor as set forth in the quarterly financial
                             statements and information of the Guarantor for the
                             fiscal quarter ending immediately preceding the
                             first day of the relevant Margin Period is greater
                             than or equal to 0.10 but less than 0.15, 1.00
                             percent per annum; or

                      (iv)   if the Guarantor has net profits of greater than
                             US$1, as determined in accordance with generally
                             accepted accounting principles and practices in the
                             United States of America as consistently applied,
                             during both the fiscal quarter ending on September
                             26, 1999 and the fiscal


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                             quarter ending on December 26, 1999 and the Senior
                             Indebtedness Ratio of the Guarantor as set forth in
                             the quarterly financial statements and information
                             of the Guarantor for the fiscal quarter ending
                             immediately preceding the first day of the relevant
                             Margin Period is greater than or equal to 0.15 but
                             less than or equal to 0.25, 1.25 percent per annum.

               (c)    Until the later of the expiry of the Purchase Commitment
                      Period and the date on which the obligation to pay the
                      Reduced Amount pursuant to Clause 10 and the repurchase
                      obligations pursuant to Clause 16 shall have been fully
                      satisfied by the Seller in respect of all the Purchased
                      Receivables, the Seller shall, unless the Majority
                      Purchasers shall otherwise consent in writing, furnish or
                      cause to be furnished to the Representative Purchaser for
                      each Purchaser the following, each in such form and such
                      detail as the Representative Purchaser shall reasonably
                      request (copies of which the Representative Purchaser
                      shall promptly deliver to each Purchaser):

                      (i)    as soon as available and in no event later than
                             fifty (50) days after the last day of each fiscal
                             quarter of the Guarantor, a copy of the Financial
                             Statements of the Guarantor and its Subsidiaries
                             (prepared on a consolidated basis) for such quarter
                             and for the fiscal year to date, certified by the
                             chief executive officer, president, chief financial
                             officer or treasurer of the Guarantor to present
                             fairly the financial condition, results of
                             operations and other information reflected therein
                             and to have been prepared in accordance with GAAP
                             (subject to normal year-end audit adjustments);

                      (ii)   as soon as available and in no event later than one
                             hundred (100) days after the close of each fiscal
                             year of the Guarantor, (A) copies of the audited
                             Financial Statements of the Guarantor and its
                             Subsidiaries (prepared on a consolidated basis) for
                             such year, prepared by independent certified public
                             accountants of recognized national standing
                             acceptable to the Representative Purchaser, and (B)
                             copies of the unqualified opinions (or qualified
                             opinions reasonably acceptable to the
                             Representative Purchaser) and management letters
                             delivered by such accountants in connection with
                             all such Financial Statements; and

                      (iii)  contemporaneously with the quarterly and year-end
                             Financial Statements required by the foregoing
                             subclauses (i) and (ii), a compliance certificate
                             (the "COMPLIANCE CERTIFICATE") of the chief
                             executive officer, president, chief financial
                             officer or treasurer of the Guarantor which (A)
                             states that no Event of Default and no Default has
                             occurred and is continuing, or, if any such Event
                             of Default or Default has occurred and is
                             continuing, a statement as to the nature thereof
                             and



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                             what action the Guarantor proposes to take with
                             respect thereto, and (B) sets forth, for the
                             quarter or year covered by such Financial
                             Statements or as of the last day of such quarter or
                             year (as the case may be), the calculation of the
                             financial ratios and tests provided in Subparagraph
                             5(l) of the Loan Guaranty.

               (d)    Notwithstanding the provisions of Clause 19.9(b), if the
                      Seller fails to deliver to the Representative Purchaser
                      the financial statements and information required under
                      subclauses (i) and (ii) of Clause 19.9(c) within the time
                      periods set forth therein (it being understood that the
                      delivery by the Guarantor to the Agent of the financial
                      statements and information required under clauses (i) and
                      (ii) of Subparagraph 4(a) of the Loan Guaranty shall be
                      deemed effective delivery by the Seller to the
                      Representative Purchaser of the financial statements and
                      information required under subclauses (i) and (ii) of
                      Clause 19.9(c)), the Applicable Margin shall be, in
                      respect of any period from and including the fifteenth day
                      following the date of such failure to and including the
                      fifteenth day following receipt by the Representative
                      Purchaser of such financial statements and information (at
                      which time Clause 19.9(b) shall apply), 1.50 percent per
                      annum.

               (e)    Except where item (i) of Clause 19.9(b) shall be
                      applicable, the Borrower shall notify the Representative
                      Purchaser of the Senior Indebtedness Ratio of the
                      Guarantor applicable to each Margin Period and shall
                      submit Margin Certificates (duly completed and signed by a
                      duly authorized officer of the Guarantor), and supporting
                      evidence in respect thereof on or before the first day of
                      such Margin Period.;

        (6) Clause 29.2 of the Original Agreement shall be amended by replacing
"0.25 percent per annum" with "0.40 percent per annum";

        (7) Exhibit I to the Original Agreement shall be replaced with Exhibit I
attached hereto; and

        (8) the Eleventh Schedule attached hereto shall be attached to and shall
form an integral part of the Original Agreement as the Eleventh Schedule
thereto.

3.      REPRESENTATIONS AND WARRANTIES

        The Seller (in such capacity and as the Collection Agent) represents and
warrants to the Representative Purchaser and the Purchasers as follows:

        (1) it has power to enter into this Agreement and perform its
obligations hereunder and has taken all necessary action required to authorize
the execution and delivery of this Agreement, and the performance of the
Original Agreement as amended by this Agreement, upon the terms and conditions
of the Original Agreement as amended by this Agreement;

        (2) all necessary consents, approvals and authorizations required in
connection with the execution, delivery, performance, validity or enforceability
of


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this Agreement have been obtained and made and are in full force and effect and
each of this Agreement and the Original Agreement as amended by this Agreement
constitutes a legal, valid and binding obligation of the Seller enforceable in
accordance with its terms;

        (3) the execution, delivery and performance of this Agreement and the
performance of the Original Agreement as amended by this Agreement will not
violate, result in a breach of, or constitute a default under, any provision of
any indenture, contract or other undertaking to which the Seller is a party or
by which it or its property is bound or of any law or any regulation or, of any
order, writ, or decree applicable to it; and

        (4) no event has occurred and no condition exists which, with the giving
of notice or lapse of time or the satisfaction of any other condition, would
constitute a Termination Event under the Original Agreement as amended by this
Agreement.

4.      CONDITIONS PRECEDENT TO THE EFFECTIVENESS OF THIS AGREEMENT

        (1) The provisions of Clause 2 hereof shall not come into effect until
the Representative Purchaser has received a confirmation letter from the
Guarantor substantially in the form of Annex A attached hereto.

        (2) The effectiveness of Clause 2 hereof is subject to the further
condition precedent that as of the Effective Date the representations and
warranties made by the Seller in Clause 3 hereof are true and accurate as if the
same had been made on such date.

5.      EXPENSES

        The Seller shall reimburse the Representative Purchaser and the
Purchasers for all reasonable expenses incurred by it in connection with the
negotiation, preparation and execution of this Agreement (including all legal
fees and expenses and any stamp and other duties and taxes to which this
Agreement is subject).






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IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed
on the day and year first before written.


THE SELLER AND THE COLLECTION AGENT

LAM RESEARCH CO., LTD.



By:
   ----------------------------------------
   Name:
   Title:



THE REPRESENTATIVE PURCHASER AND INITIAL PURCHASER

ABN AMRO BANK N.V., TOKYO BRANCH




By:
   ----------------------------------------
   Name:
   Title:




By:
   ----------------------------------------
   Name:
   Title:


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                                     ANNEX A

                    [LETTERHEAD OF LAM RESEARCH CORPORATION]



                                                          Date: December 25,1998


ABN AMRO Bank N.V.
Tokyo Branch
as Representative Purchaser
to the Purchase Agreement referred to below
Shiroyama JT Mori Building
4-3-1, Toranomon,
Minato-ku, Tokyo 105-6013
Japan

Dear Sirs:

                       Re: Receivables Purchase Agreement

               We refer to a Receivables Purchase Agreement dated December 26,
1997 (the "ORIGINAL AGREEMENT") between Lam Research Co., Ltd. ("LAM JAPAN") as
Seller, the banks and other institutions named therein as Purchasers, ABN AMRO
Bank N.V., Tokyo Branch as Representative Purchaser and Lam Japan as Collection
Agent and a Supplemental Agreement dated December 25, 1998 (the "SUPPLEMENTAL
AGREEMENT") between Lam Japan as Seller, the banks and other institutions named
therein as Purchasers, ABN AMRO Bank N.V., Tokyo Branch as Representative
Purchaser and Initial Purchaser and Lam Japan as Collection Agent. Terms defined
in the Original Agreement as amended by the Supplemental Agreement shall have
the same meanings herein, unless otherwise defined herein.

               We give consent to the amendments of the Original Agreement by
the Supplemental Agreement and confirm that our obligations and liabilities
under the Guaranty dated as of December 26, 1997 executed by us in connection
with the Original Agreement will continue and remain in full force and effect
with respect to the Original Agreement as amended.



                                    Very truly yours,

                                    LAM RESEARCH CORPORATION


                                    By:
                                       --------------------------------
                                       Name:
                                       Title:


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                                    EXHIBIT I

                             PURCHASER'S COMMITMENTS
                  (subject to the third sentence of Clause 2.1)





Purchaser(s) and their/its Address                                            Commitment(s)
- ----------------------------------                                            -------------
                                                                                   
ABN AMRO Bank N.V.                                                          (Y)4,000,000,000
Tokyo Branch
13F, Shiroyama JT Mori Building
4-3-1, Toranomon, Minato-ku
Tokyo 105-6013
Telefax:  81-3-5405-6903/6902
Attention:  Structured Finance


                                                                       Total (Y)4,000,000,000
                                                                                -------------




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                              THE ELEVENTH SCHEDULE

                           FORM OF MARGIN CERTIFICATE



        To:    [Name and address of Representative Purchaser]



Attention:                                                              [Date]



       Receivables Purchase Agreement of December 26, 1997 (as amended by
                  Supplemental Agreement of December 25, 1998)


        We refer to the above Supplemental Agreement (terms used in this letter
having the meanings given to them in that Agreement) and notify you that the
Senior Indebtedness Ratio of the Guarantor as set forth in the quarterly
financial statements and information of the Guarantor for the fiscal quarter
ending on [          ] is [         ].



                                    for and on behalf of
                                    LAM RESEARCH CORPORATION



                                    By:
                                       --------------------------------
                                       Name:
                                       Title: