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                                                                    EXHIBIT 23.1


                         CONSENT OF INDEPENDENT AUDITORS

We consent to the incorporation by reference in the Registration Statement (Form
S-8) pertaining to the 1999 Stock Option Plan of Lam Research Corporation of our
report dated July 20, 2001, with respect to the consolidated financial
statements and schedule of Lam Research Corporation included in its Annual
Report (Form 10-K) for the year ended June 24, 2001, filed with the Securities
and Exchange Commission.

                                            /s/ ERNST & YOUNG LLP


San Jose, California
November 29, 2001

