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                                                                     EXHIBIT 4.2



                    CERTIFICATE OF DESIGNATION, PREFERENCES
                         AND RIGHTS OF SERIES A JUNIOR
                         PARTICIPATING PREFERRED STOCK

                                       OF

                            LAM RESEARCH CORPORATION


             Pursuant to Section 151 of the General Corporation Law
                            of the State of Delaware
                                        

          The undersigned officers of Lam Research Corporation, a corporation
organized and existing under the General Corporation Law of the State of
Delaware, in accordance with the provisions of Section 103 thereof, DO HEREBY
CERTIFY:

          That pursuant to the authority conferred upon the Board of Directors
by the Certificate of Incorporation of the said Corporation, the said Board of
Directors on January 23, 1997, adopted the following resolution creating a
series of one hundred thousand (100,000) shares of Preferred Stock designated as
"Series A Junior Participating Preferred Stock:"

          RESOLVED, that pursuant to the authority vested in the Board of
Directors of this Corporation in accordance with the provisions of its
Certificate of Incorporation, a series of Preferred Stock of the Corporation be
and it hereby is created, and that the designation and amount thereof and the
voting powers, preferences and relative, participating, optional and other
special rights of the shares of such series, and the qualifications, limitations
or restrictions thereof are as follows:

          Section 1.  Designation and Amount.  The shares of such series shall
                      ----------------------                                  
be designated as "Series A Junior Participating Preferred Stock" and the number
of shares constituting such series shall be one hundred thousand (100,000).

          Section 2.  Dividends and Distributions.
                      --------------------------- 

          (A)  The holders of shares of Series A Junior Participating Preferred
Stock shall be entitled to receive, when, as and if declared by the Board of
Directors out of funds legally available for the purpose, quarterly dividends
payable in cash on the last day of March, June, September and December in each
year (each such date being referred to herein as a "Quarterly Dividend Payment
Date"), commencing on the first

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Quarterly Dividend Payment Date after the first issuance of a share or fraction
of a share of Series A Junior Participating Preferred Stock, in an amount per
share (rounded to the nearest cent) equal to the greater of (a) $.01 or (b)
subject to the provision for adjustment set forth below, one thousand (1,000)
times the aggregate per share amount of all cash dividends, and one thousand
(1,000) times the aggregate per share amount (payable in kind) of all non-cash
dividends or other distributions other than a dividend payable in shares of
Common Stock or a subdivision of the outstanding shares of Common Stock (by
reclassification or otherwise), declared on the Common Stock, par value $.001
per share, of the Corporation (the "Common Stock") since the immediately
preceding Quarterly Dividend Payment Date, or, with respect to the first
Quarterly Dividend Payment Date, since the first issuance of any share or
fraction of a share of Series A Junior Participating Preferred Stock.  In the
event the Corporation shall at any time after January 23, 1997 (the "Rights
Dividend Declaration Date") (i) declare any dividend on Common Stock payable in
shares of Common Stock, (ii) subdivide the outstanding Common Stock or (iii)
combine the outstanding Common Stock into a smaller number of shares, then in
each such case the amount to which holders of shares of Series A Junior
Participating Preferred Stock were entitled immediately prior to such event
under clause (b) of the preceding sentence shall be adjusted by multiplying such
amount by a fraction the numerator of which is the number of shares of Common
Stock outstanding immediately after such event and the denominator of which is
the number of shares of Common Stock that were outstanding immediately prior to
such event.

          (B)  The Corporation shall declare a dividend or distribution on the
Series A Junior Participating Preferred Stock as provided in subsection (A)
above immediately after it declares a dividend or distribution on the Common
Stock (other than a dividend payable in shares of Common Stock); provided that,
in the event no dividend or distribution shall have been declared on the Common
Stock during the period between any Quarterly Dividend Payment Date and the next
subsequent Quarterly Dividend Payment Date, a dividend of $.01 per share on the
Series A Junior Participating Preferred Stock shall nevertheless be payable on
such subsequent Quarterly Dividend Payment Date.

          (C)  Dividends shall begin to accrue and be cumulative on outstanding
shares of Series A Junior Participating Preferred Stock from the Quarterly
Dividend Payment Date next preceding the date of issue of such shares of Series
A Junior Participating Preferred Stock, unless the date of issue of such shares
is prior to the record date for the first Quarterly Dividend Payment Date, in
which case dividends on such shares shall begin to accrue from the date of issue
of such shares, or unless the date of issue is a Quarterly Dividend Payment Date
or is a date after the record date for the determination of holders of shares of
Series A Junior Participating Preferred Stock entitled to receive a quarterly
dividend and before such Quarterly Dividend Payment Date, in either of which
events such dividends shall begin to accrue and be cumulative from such
Quarterly Dividend Payment Date.  Accrued but unpaid dividends shall not bear
interest.  Dividends paid on the shares of Series A Junior Participating
Preferred Stock in an amount less than the total amount of such dividends at the
time accrued and

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payable on such shares shall be allocated pro rata on a share-by-share basis
among all such shares at the time outstanding.  The Board of Directors may fix a
record date for the determination of holders of shares of Series A Junior
Participating Preferred Stock entitled to receive payment of a dividend or
distribution declared thereon, which record date shall be no more than 30 days
prior to the date fixed for the payment thereof.

          Section 3.  Voting Rights.  The holders of shares of Series A Junior
                      -------------                                           
Participating Preferred Stock shall have the following voting rights:

          (A)  Subject to the provision for adjustment set forth below, each
share of Series A Junior Participating Preferred Stock shall entitle the holder
thereof to one thousand (1,000) votes on all matters submitted to a vote of the
stockholders of the Corporation.  In the event the Corporation shall at any time
after the Rights Dividend Declaration Date (i) declare any dividend on Common
Stock payable in shares of Common Stock, (ii) subdivide the outstanding Common
Stock or (iii) combine the outstanding Common Stock into a smaller number of
shares, then in each such case the number of votes per share to which holders of
shares of Series A Junior Participating Preferred Stock were entitled
immediately prior to such event shall be adjusted by multiplying such number by
a fraction the numerator of which is the number of shares of Common Stock
outstanding immediately after such event and the denominator of which is the
number of shares of Common Stock that were outstanding immediately prior to such
event.

          (B)  Except as otherwise provided herein or by law, the holders of
shares of Series A Junior Participating Preferred Stock and the holders of
shares of Common Stock shall vote together as one class on all matters submitted
to a vote of stockholders of the Corporation.

          (C)  (i)  If at any time dividends on any Series A Junior
     Participating Preferred Stock shall be in arrears in an amount equal to six
     (6) quarterly dividends thereon, the occurrence of such contingency shall
     mark the beginning of a period (herein called a "default period") which
     shall extend until such time when all accrued and unpaid dividends for all
     previous quarterly dividend periods and for the current quarterly dividend
     period on all shares of Series A Junior Participating Preferred Stock then
     outstanding shall have been declared and paid or set apart for payment.
     During each default period, all holders of Preferred Stock (including
     holders of the Series A Junior Participating Preferred Stock) with
     dividends in arrears in an amount equal to or greater than six (6)
     quarterly dividends thereon, voting as a class, irrespective of series,
     shall have the right to elect two (2) Directors.

               (ii)  During any default period, such voting right of the holders
     of Series A Junior Participating Preferred Stock may be exercised
     initially at a special meeting called pursuant to subsection (iii) of

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     this Section 3(C) or at any annual meeting of stockholders, and thereafter
     at annual meetings of stockholders, provided that such voting right shall
     not be exercised unless the holders of ten percent (10%) in number of
     shares of Preferred Stock outstanding shall be present in person or by
     proxy.  The absence of a quorum of the holders of Common Stock shall not
     affect the exercise by the holders of Preferred Stock of such voting right.
     At any meeting at which the holders of Preferred Stock shall exercise such
     voting right initially during an existing default period, they shall have
     the right, voting as a class, to elect Directors to fill such vacancies, if
     any, in the Board of Directors as may then exist up to two (2) Directors
     or, if such right is exercised at an annual meeting, to elect two (2)
     Directors.  If the number which may be so elected at any special meeting
     does not amount to the required number, the holders of the Preferred Stock
     shall have the right to make such increase in the number of Directors as
     shall be necessary to permit the election by them of the required number.
     After the holders of the Preferred Stock shall have exercised their right
     to elect Directors in any default period and during the continuance of such
     period, the number of Directors shall not be in creased or decreased except
     by vote of the holders of Preferred Stock as herein provided or pursuant to
     the rights of any equity securities ranking senior to or pari passu with
                                                              ---- -----     
     the Series A Junior Participating Preferred Stock.

               (iii)  Unless the holders of Preferred Stock shall, during an
     existing default period, have previously exercised their right to elect
     Directors, the Board of Directors may order, or any stockholder or
     stockholders owning in the aggregate not less than ten percent (10%) of the
     total number of shares of Preferred Stock outstanding, irrespective of
     series, may request, the calling of special meeting of the holders of
     Preferred Stock, which meeting shall thereupon be called by the President,
     a Vice President or the Secretary of the Corporation.  Notice of such
     meeting and of any annual meeting at which holders of Preferred Stock are
     entitled to vote pursuant to this subsection (C)(iii) shall be given to
     each holder of record of Preferred Stock by mailing a copy of such notice
     to him at his last address as the same appears on the books of the
     Corporation.  Such meeting shall be called for a time not earlier than 20
     days and not later than 60 days after such order or request or in default
     of the calling of such meeting within 60 days after such order or request,
     such meeting may be called on similar notice by any stockholder or
     stockholders owning in the aggregate not less than ten percent (10%) of the
     total number of shares of Preferred Stock outstanding.  Notwith-

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     standing the provisions of this subsection (C)(iii), no such special
     meeting shall be called during the period within 60 days immediately
     preceding the date fixed for the next annual meeting of the stockholders.

               (iv)  In any default period, the holders of Common Stock, and
     other classes of stock of the Corporation if applicable, shall continue to
     be entitled to elect the whole number of Directors until the holders of
     Preferred Stock shall have exercised their right to elect two (2) Directors
     voting as a class, after the exercise of which right (x) the Directors so
     elected by the holders of Preferred Stock shall continue in office until
     their successors shall have been elected by such holders or until the
     expiration of the default period, and (y) any vacancy in the Board of
     Directors may (except as provided in subsection (C)(ii) of this Section 3)
     be filled by vote of a majority of the remaining Directors theretofore
     elected by the holders of the class of stock which elected the Director
     whose office shall have become vacant.  References in this subsection (C)
     to Directors elected by the holders of a particular class of stock shall
     include Directors elected by such Directors to fill vacancies as provided
     in clause (y) of the foregoing sentence.

               (v)  Immediately upon the expiration of a default period, (x) the
     right of the holders of Preferred Stock as a class to elect Directors
     shall cease, (y) the term of any Directors elected by the holders of
     Preferred Stock as a class shall terminate and (z) the number of Directors
     shall be such number as may be provided for in the certificate of in
     corporation or by-laws irrespective of any increase made pursuant to the
     provisions of subsection (C)(ii) of this Section 3 (such number being
     subject, however, to change thereafter in any manner provided by law or in
     the certificate of incorporation or by-laws).  Any vacancies in the Board
     of Directors effected by the provisions of clauses (y) and (z) in the
     preceding sentence may be filled by a majority of the remaining Directors.

          (D)  Except as set forth herein, holders of Series A Junior
Participating Preferred Stock shall have no special voting rights and their
consent shall not be required (except to the extent they are entitled to vote
with holders of Common Stock as set forth herein) for taking any corporate
action.

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          Section 4.  Certain Restrictions.
                      -------------------- 

          (A)  Whenever quarterly dividends or other dividends or distributions
payable on the Series A Junior Participating Preferred Stock as provided in
Section 2 are in arrears, thereafter and until all accrued and unpaid dividends
and distributions, whether or not declared, on shares of Series A Junior
Participating Preferred Stock outstanding shall have been paid in full, the
Corporation shall not:

               (i)  declare or pay dividends on, make any other distributions
     on, or redeem or purchase or otherwise acquire for consideration any
     shares of stock ranking junior (either as to dividends or upon liquidation,
     dissolution or winding up) to the Series A Junior Participating Preferred
     Stock;

               (ii)  declare or pay dividends on or make any other distributions
     on any shares of stock ranking on a parity (either as to dividends or upon
     liquidation, dissolution or winding up) with the Series A Junior
     Participating Preferred Stock, except dividends paid ratably on the Series
     A Junior Participating Preferred Stock and all such parity stock on which
     dividends are payable or in arrears in proportion to the total amounts to
     which the holders of all such shares are then entitled;

               (iii)  redeem or purchase or otherwise acquire for consideration
     shares of any stock ranking on a parity (either as to dividends or upon
     liquidation, dissolution or winding up) with the Series A Junior
     Participating Preferred Stock, provided that the Corporation may at any
     time redeem, purchase or otherwise acquire shares of any such parity stock
     in exchange for shares of any stock of the Corporation ranking junior
     (either as to dividends or upon dissolution, liquidation or winding up) to
     the Series A Junior Participating Preferred Stock; or

               (iv)  purchase or otherwise acquire for consideration any shares
     of Series A Junior Participating Preferred Stock, or any shares of stock
     ranking on a parity with the Series A Junior Participating Preferred Stock,
     except in accordance with a purchase offer made in writing or by
     publication (as determined by the Board of Directors) to all holders of
     such shares upon such terms as the Board of Directors, after consideration
     of the respective annual dividend rates and other relative rights and
     preferences of the respective series and classes, shall determine in good
     faith will result in fair and equitable treatment among the respective
     series or classes.

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          (B)  The Corporation shall not permit any subsidiary of the
Corporation to purchase or otherwise acquire for consideration any shares of
stock of the Corporation unless the Corporation could, under subsection (A) of
this Section 4, purchase or otherwise acquire such shares at such time and in
such manner.

          Section 5.  Reacquired Shares.  Any shares of Series A Junior
                      -----------------                                
Participating Preferred Stock purchased or otherwise acquired by the
Corporation in any manner whatsoever shall be retired and cancelled promptly
after the acquisition thereof.  All such shares shall upon their cancellation
become authorized but unissued shares of Preferred Stock and may be reissued as
part of a new series of Preferred Stock to be created by resolution or
resolutions of the Board of Directors, subject to the conditions and
restrictions on issuance set forth herein.

          Section 6.  Liquidation, Dissolution or Winding Up.  (A)  Upon any
                      --------------------------------------                
liquidation (voluntary or otherwise), dissolution or winding up of the
Corporation, no distribution shall be made to the holders of shares of stock
ranking junior (either as to dividends or upon liquidation, dissolution or
winding up) to the Series A Junior Participating Preferred Stock unless, prior
thereto, the holders of shares of Series A Junior Participating Preferred Stock
shall have received an amount equal to $[one thousand times the Purchase Price]
per share of Series A Junior Participating Preferred Stock, plus an amount equal
to accrued and unpaid dividends and distributions thereon, whether or not
declared, to the date of such payment (the "Series A Liquidation Preference").
Following the payment of the full amount of the Series A Liquidation
Preference, no additional distributions shall be made to the holders of shares
of Series A Junior Participating Preferred Stock unless, prior thereto, the
holders of shares of Common Stock shall have received an amount per share (the
"Common Adjustment") equal to the quotient obtained by dividing (i) the Series A
Liquidation Preference by (ii) one thousand (1,000) (as appropriately adjusted
as set forth in subsection (C) below to reflect such events as stock splits,
stock dividends and recapitalizations with respect to the Common Stock) (such
number in clause (ii), the "Adjustment Number").  Following the payment of the
full amount of the Series A Liquidation Preference and the Common Adjustment in
respect of all outstanding shares of Series A Junior Participating Preferred
Stock and Common Stock, respectively, holders of Series A Junior Participating
Preferred Stock and holders of shares of Common Stock shall receive their
ratable and proportionate share of the remaining assets to be distributed in the
ratio of the Adjustment Number to 1 with respect to such Preferred Stock and
Common Stock, on a per share basis, respectively.

          (B)  In the event, however, that there are not sufficient assets
available to permit payment in full of the Series A Liquidation Preference and
the liquidation preferences of all other series of preferred stock, if any,
which rank on a parity with the Series A Junior Participating Preferred Stock,
then such remaining assets shall be

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distributed ratably to the holders of such parity shares in proportion to their
respective liquidation preferences.  In the event, however, that there are not
sufficient assets available to permit payment in full of the Common Adjustment,
then such remaining assets shall be distributed ratably to the holders of
Common Stock.

          (C)  In the event the Corporation shall at any time after the Rights
Dividend Declaration Date (i) declare any dividend on Common Stock payable in
shares of Common Stock, (ii) subdivide the outstanding Common Stock, or (iii)
combine the outstanding Common Stock into a smaller number of shares, then in
each such case the Adjustment Number in effect immediately prior to such event
shall be adjusted by multiplying such Adjustment Number by a fraction the
numerator of which is the number of shares of Common Stock outstanding
immediately after such event and the denominator of which is the number of
shares of Common Stock that were outstanding immediately prior to such event.

          Section 7.  Consolidation, Merger, etc.  In case the Corporation shall
                      --------------------------                                
enter into any consolidation, merger, combination or other transaction in which
the shares of Common Stock are exchanged for or changed into other stock or
securities, cash and/or any other property, then in any such case the shares of
Series A Junior Participating Preferred Stock shall at the same time be
similarly exchanged or changed in an amount per share (subject to the provision
for adjustment set forth below) equal to one thousand (1,000) times the
aggregate amount of stock, securities, cash and/or any other property (payable
in kind), as the case may be, into which or for which each share of Common Stock
is changed or exchanged.  In the event the Corporation shall at any time after
the Rights Dividend Declaration Date (i) declare any dividend on Common Stock
payable in shares of Common Stock, (ii) subdivide the outstanding Common Stock,
or (iii) combine the outstanding Common Stock into a smaller number of shares,
then in each such case the amount set forth in the preceding sentence with
respect to the exchange or change of shares of Series A Junior Participating
Preferred Stock shall be adjusted by multiplying such amount by a fraction the
numerator of which is the number of shares of Common Stock outstanding
immediately after such event and the denominator of which is the number of
shares of Common Stock that were outstanding immediately prior to such event.

          Section 8.  No Redemption.  The shares of Series A Junior
                      -------------                                
Participating Preferred Stock shall not be redeemable.

          Section 9.  Amendment.  The Certificate of Incorporation of the
                      ---------                                          
Corporation shall not be further amended in any manner which would materially
alter or change the powers, preferences or special rights of the Series A Junior
Participating Preferred Stock so as to affect them adversely without the
affirmative vote of the holders

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of a majority or more of the outstanding shares of Series A Junior Participating
Preferred Stock, voting separately as a class.

          Section 10.  Fractional Shares.  Series A Junior Participating
                       -----------------                                
Preferred Stock may be issued in fractions of a share which shall entitle the
holder, in proportion to such holder's fractional shares, to exercise voting
rights, receive dividends, participate in distributions and to have the benefit
of all other rights of holders of Series A Junior Participating Preferred Stock.

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          IN WITNESS WHEREOF, we have executed and subscribed this Certificate
and do affirm the foregoing as true under the penalties of perjury this 29th day
of January 1997.


                                       LAM RESEARCH CORPORATION


                                       /s/ Rick P. Friedman
                                       --------------------------------------
                                       Name:   Rick P. Friedman
                                       Title:  Vice President, Worldwide
                                               Sales and Field Operations



Attest:

/s/ Richard H. Lovgren
-------------------------
Secretary
Richard H. Lovgren

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