<SUBMISSION>
<ACCESSION-NUMBER>0001227050-03-000007
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>2
<PERIOD>20030530
<FILING-DATE>20030602
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>LAM RESEARCH CORP
<CIK>0000707549
<ASSIGNED-SIC>3559
<IRS-NUMBER>942634797
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>0630
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>4650 CUSHING BLVD
<CITY>FREMONT
<STATE>CA
<ZIP>94538
<PHONE>5106590200
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>4650 CUSHING PARKWAY
<CITY>FREMONT
<STATE>CA
<ZIP>94538
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>MADDOCK ERNEST E
<CIK>0001227050
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-12933
<FILM-NUMBER>03728512
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>4650 CUSHING PARKWAY CA4
<CITY>FREMONT
<STATE>CA
<ZIP>94070
<PHONE>510-572-6474
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>2209 CHAMPLAIN COURT
<CITY>UNION CITY
<STATE>CA
<ZIP>94537
</MAIL-ADDRESS>
<FORMER-NAME>
<FORMER-CONFORMED-NAME>MADDOCK ERNIE
<DATE-CHANGED>20030411
</FORMER-NAME>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>2003-05-30</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000707549</issuerCik>
        <issuerName>LAM RESEARCH CORP</issuerName>
        <issuerTradingSymbol>lrcx</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001227050</rptOwnerCik>
            <rptOwnerName>MADDOCK ERNEST E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>V.P. Customer Svc, Bus Grp</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock</value>
        </securityTitle>
        <transactionDate>
            <value>2003-05-30</value>
        </transactionDate>
        <deemedExecutionDate>
            <value>2003-05-30</value>
        </deemedExecutionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>S</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>5000</value>
            </transactionShares>
            <transactionValue>
                <value>17.601</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>D</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>289</value>
                <footnoteId id="F1"/>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <footnotes>
        <footnote id="F1">Indirect Beneficial Ownership:  2,944 held in Maddock 2000 Trust, dtd 4/18/00, E. Maddock TTEE</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Sandra Blum by power of attorney</signatureName>
        <signatureDate>2003-05-30</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>3
<FILENAME>ex24maddock.htm
<DESCRIPTION>POWER OF ATTORNEY
<TEXT>


<TITLE>POWER OF ATTORNEY</TITLE>
</HEAD>
<BODY>

<B><FONT FACE="Arial" SIZE=2><P ALIGN="CENTER">POWER OF ATTORNEY</P>
</B><P ALIGN="JUSTIFY"></P>
<P ALIGN="JUSTIFY">Know all by these presents, that the undersigned hereby
constitutes and appoints each of <B><U>George Schisler</B>, <I>General
Counsel</I>,<B> Martin Anstice, </B><I>Corporate Controller</I><B> </B>and<B>
Sandra Blum, </B><I>Manager, Employee</I><B> </B><I>Shareholder
Services</I></U>, signing singly, the undersigned's true and lawful attorney-in-
fact to:</P>
<P ALIGN="JUSTIFY"></P><DIR>
<DIR>
<DIR>
<DIR>

<P ALIGN="JUSTIFY">(1)&#9;&#9;execute for and on behalf of the undersigned, in
the undersigned's capacity as an officer and/or director of <B><U>Lam Research
Corporation</B></U>  (the &quot;Company&quot;), Forms&nbsp;3, 4, and 5 in
accordance with Section&nbsp;16(a) of the Securities Exchange Act of 1934 and
the rules thereunder;</P>
<P ALIGN="JUSTIFY"></P>
<P ALIGN="JUSTIFY">(2)&#9;&#9;do and perform any and all acts for and on behalf
of the undersigned which may be necessary or desirable to complete and execute
any such Form&nbsp;3, 4, or 5, complete and execute any amendment or amendments
thereto, and timely file such form with the United States Securities and
Exchange Commission and any stock exchange or similar authority; and</P>
<P ALIGN="JUSTIFY"></P>
<P ALIGN="JUSTIFY">(3)&#9;take any other action of any type whatsoever in
connection with the foregoing which, in the opinion of such attorney-in-fact,
may be of benefit to, in the best interest of, or legally required by, the
undersigned, it being understood that the documents executed by such attorney-
in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be
in such form and shall contain such terms and conditions as such attorney-in-
fact may approve in such attorney-in-fact's discretion.</P>
<P ALIGN="JUSTIFY"></P></DIR>
</DIR>
</DIR>
</DIR>

<P ALIGN="JUSTIFY">&#9;The undersigned hereby grants to each such attorney-in-
fact full power and authority to do and perform any and every act and thing
whatsoever requisite, necessary, or proper to be done in the exercise of any of
the rights and powers herein granted, as fully to all intents and purposes as
the undersigned might or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming all that such
attorney-in-fact, or such attorney-in-fact's substitute or substitutes, shall
lawfully do or cause to be done by virtue of this power of attorney and the
rights and powers herein granted.  The undersigned acknowledges that the
foregoing attorneys-in-fact, in serving in such capacity at the request of the
undersigned, are not assuming, nor is the Company assuming, any of the
undersigned's responsibilities to comply with Section&nbsp;16 of the Securities
Exchange Act of 1934.</P>
<P ALIGN="JUSTIFY"></P>
<P ALIGN="JUSTIFY">&#9;This Power of Attorney shall remain in full force and
effect until the undersigned is no longer required to file Forms&nbsp;3, 4, and
5 with respect to the undersigned's holdings of and transactions in securities
issued by the Company, unless earlier revoked by the undersigned in a signed
writing delivered to the foregoing attorneys-in-fact.</P>
<P ALIGN="JUSTIFY"></P>
<P ALIGN="JUSTIFY">&#9;IN WITNESS WHEREOF, the undersigned has caused this Power
of Attorney to be executed as of this<B> <U> 30<SUP>th</SUP> day of March 2003.
</P>
</B></U><P ALIGN="JUSTIFY"></P>
<P ALIGN="JUSTIFY">&nbsp;</P>
<P ALIGN="JUSTIFY">&#9;&#9;<U>/s/   Ernest E. Maddock</P>
</U><P ALIGN="JUSTIFY">&#9;&#9;Signature</P>
<P ALIGN="JUSTIFY"></P>
<P ALIGN="JUSTIFY">&#9;             Ernest E. Maddock</P>
<P ALIGN="JUSTIFY">&#9;&#9;Print Name</P>
</FONT><FONT FACE="Century Schoolbook,Bookman Old Style" SIZE=2>
</FONT><FONT FACE="Century Schoolbook,Bookman Old Style"><P>&nbsp;</P></FONT>


</TEXT>
</DOCUMENT>
</SUBMISSION>
