UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

FORM 8-K

Current Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported): July 21, 2004

LAM RESEARCH CORPORATION

Delaware
(State of Other Jurisdiction of Incorporation)

4650 Cushing Parkway
Fremont, California 94538
(Address of principal executive offices including zip code)

(510) 572-0200
(Registrant’s telephone number, including area code)

Not Applicable
(Former name or former address, if changed since last report)

Table of Contents

Item 9. Regulation FD Disclosure

On July 21, 2004, Lam Research Corporation announced plans to cease investment in CMP systems development. A copy of the press release issued by Lam Research Corporation on July 21, 2004 is attached as Exhibit 99.2.

Item 12. Results of Operations and Financial Condition

On July 21, 2004, Lam Research Corporation (the Company) issued a press release announcing its earnings for the fiscal quarter ended June 27, 2004, the text of which is attached hereto as Exhibit 99.1.

The information in this Current Report on Form 8-K, including the exhibits, is furnished pursuant to Items 9 and 12 and shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities under that Section. Furthermore, the information in the Current Report on Form 8-K, including the exhibits, shall not be deemed to be incorporated by reference into the filings of the Company under the Securities Act of 1933, as amended.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

EXHIBIT INDEX