Lam Research + KLA-Tencor Creating a New Capability Paradigm October 21, 2015 Filed by KLA-Tencor Corporation Pursuant to Rule 425 under the Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 under the Securities Exchange Act of 1934 Subject Company: KLA-Tencor Corporation Commission File No.: 000-09992

2 KLA-Tencor Confidential - Internal Use Only The Right Combination at the Right Time Cloud, mobility, and IoT are driving performance and economic requirements Technology scaling continues with escalating challenges Customer roadmaps require enhanced collaboration and innovation Intersection of process and process control becoming more critical Unmatched and complementary capability to enable atomic level processing Accelerating our capability to address our customers’ most difficult challenges

3 Our Businesses at a Glance Founded in 1980 Headquartered in Fremont, CA FY 2015 Revenue of $5.3B ~7,300 Employees Leadership in: Conductor and dielectric etch Thin film deposition Single-wafer clean Locations in 16 countries Founded in 1976 Headquartered in Milpitas, CA FY 2015 Revenue of $2.8B ~5,600 Employees Leadership in: Defect inspection Lithography & thin film metrology Yield management Locations in 17 countries Strong presence across customers and market segments KLA-Tencor Confidential - Internal Use Only

Challenges: Critical profile control Variability Opportunities: Increased use of metrology information and advanced analytics to reduce variability and accelerate yield Multiple Patterning Challenges: Variability introduced from multiple passes  Cost of advanced imaging schemes Opportunities: Use metrology information and unit process tuning capabilities to reduce variability and increase throughput 3D NAND Challenges: Scaling stack height for higher bit density Scaling process control capability Opportunities: Innovate together to develop process control capability for 3D NAND structures to help enable vertical scaling Value-creating innovation opportunities at the intersection of process and process control Delivering Differentiated Technology Solutions Together 4 KLA-Tencor Confidential - Internal Use Only FinFET/ Advanced Gate

Deposition Etch Clean Inspection Metrology 7% – 9% of WFE 14% – 16% of WFE 5% – 6% of WFE 6% - 7% of WFE 6% - 7% of WFE in Conductor in Dielectric in Bevel Clean in BEOL SW Clean in Wafer Inspection in Mask Inspection in Packaging Inspection in Metrology Established Market Leadership Combined company to serve ~42% of WFE market upon closing, increasing to ~45% by 2018 Source:  Leadership positions based on Gartner and company data specific to 2014 shares. WFE percentages are for 2015 markets based on Gartner and company data. ECD = electrochemical deposition, CVD = chemical vapor deposition, PECVD = plasma-enhanced CVD, HDP = high-density plasma (CVD), ALD = atomic layer deposition, BEOL = back-end-of-line, SW = single-wafer. *Based on year-over-year absolute revenue growth.  WFE = wafer fabrication equipment KLA-Tencor Confidential - Internal Use Only 5 in Copper ECD in Tungsten CVD in PECVD & HDP in ALD*

6 KLA-Tencor Confidential - Internal Use Only Our Goal Is to Deliver More Value This combination creates a company with unmatched capability in process and process control to help our customers in extending Moore’s law and industry scaling Together, we will have enhanced collaboration focused on reducing variability and accelerating yield By taking this action, we have one singular focus:  enable and contribute more to your success It will be business as usual until we have shareholder and regulatory approval We appreciate your feedback over the past several years, which helped us frame the strategic actions we are now pursuing Thank you for your continued support and partnership

Copyright © 2015 KLA-Tencor Corporation www.kla-tencor.com

Cautions Regarding Forward Looking Statements All statements included or incorporated by reference in this document, other than statements or characterizations of historical fact, are forward-looking statements within the meaning of the federal securities laws, including Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. These forward-looking statements are based on Lam Research Corporation’s (Lam) and KLA-Tencor Corporation’s (KLA-Tencor) current expectations, estimates and projections about its respective business and industry, management’s beliefs, and certain assumptions made by Lam and KLA-Tencor, all of which are subject to change. Forward-looking statements can often be identified by words such as “anticipates,” “expects,” “intends,” “plans,” “predicts,” “believes,” “seeks,” “estimates,” “may,” “will,” “should,” “would,” “could,” “potential,” “continue,” “ongoing,” similar expressions, and variations or negatives of these words. Examples of such forward-looking statements include, but are not limited to: (1) references to the anticipated benefits of the proposed transaction; (2) the expected industry leadership, future technical capabilities and served markets of the individual and/or combined companies; (3) projections of pro forma revenue, cost synergies, revenue synergies, cash flow, market share and other metrics, whether by specific market segment, or as a whole, and whether for each individual company or the combined company; (4) market expansion opportunities and systems and products that may benefit from sales growth as a result of changes in market share or existing markets; (5) technological achievements that may be realized by the combined company, (6) the allocation of merger consideration in the transactions; (7) the financing components of the proposed transaction; (8) potential financing opportunities, together with sources and uses of cash; (9) potential dividend growth rates; and (10) the companies’ ability to achieve the closing conditions and the expected date of closing of the transaction. 8 KLA-Tencor Confidential - Internal Use Only

9 KLA-Tencor Confidential - Internal Use Only Cautions Regarding Forward Looking Statements (cont.) These forward-looking statements are not guarantees of future results and are subject to risks, uncertainties and assumptions that could cause actual results to differ materially and adversely from those expressed in any forward-looking statement. Important risk factors that may cause such a difference in connection with the proposed transaction include, but are not limited to, the following factors: (1) the risk that the conditions to the closing of the transaction are not satisfied, including the risk that required approvals for the transaction from governmental authorities or the stockholders of KLA-Tencor or Lam are not obtained; (2) litigation relating to the transaction; (3) uncertainties as to the timing of the consummation of the transaction and the ability of each party to consummate the transaction; (4) risks that the proposed transaction disrupts the current plans and operations of KLA-Tencor or Lam; (5) the ability of KLA-Tencor and Lam to retain and hire key personnel; (6) competitive responses to the proposed transaction and the impact of competitive products; (7) unexpected costs, charges or expenses resulting from the transaction; (8) potential adverse reactions or changes to business relationships resulting from the announcement or completion of the transaction; (9) the combined companies’ ability to achieve the growth prospects and synergies expected from the transaction, as well as delays, challenges and expenses associated with integrating the combined companies’ existing businesses; (10) the terms and availability of the indebtedness planned to be incurred in connection with the transaction; and (11) legislative, regulatory and economic developments, including changing business conditions in the semiconductor industry and overall economy as well as the financial performance and expectations of Lam’s and KLA-Tencor’s existing and prospective customers. These risks, as well as other risks associated with the proposed transaction, will be more fully discussed in the joint proxy statement/prospectus that will be included in the Registration Statement on Form S-4 that Lam will file with the Securities and Exchange Commission (“SEC”) in connection with the proposed transaction. Investors and potential investors are urged not to place undue reliance on forward-looking statements in this document, which speak only as of this date. Neither Lam nor KLA-Tencor undertakes any obligation to revise or update publicly any forward-looking statement to reflect future events or circumstances. Nothing contained herein constitutes or will be deemed to constitute a forecast, projection or estimate of the future financial performance of Lam, KLA-Tencor, or the merged company, whether following the implementation of the proposed transaction or otherwise. In addition, actual results are subject to other risks and uncertainties that relate more broadly to Lam’s overall business, including those more fully described in Lam’s filings with the SEC including its annual report on Form 10-K for the fiscal year ended June 28, 2015, and KLA-Tencor’s overall business and financial condition, including those more fully described in KLA-Tencor’s filings with the SEC including its annual report on Form 10-K for the fiscal year ended June 30, 2015.

Additional Information and Where to Find It This document does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. The proposed transaction will be submitted to the stockholders of each of Lam Research Corporation (Lam) and KLA-Tencor Corporation (KLA-Tencor) for their consideration. Lam intends to file with the SEC a Registration Statement on Form S-4 that will include a joint proxy statement/prospectus of Lam and KLA-Tencor. Each of Lam and KLA-Tencor will provide the joint proxy statement/prospectus to their respective stockholders. Lam and KLA-Tencor also plan to file other documents with the SEC regarding the proposed transaction. This document is not a substitute for any prospectus, proxy statement or any other document that Lam or KLA-Tencor may file with the SEC in connection with the proposed transaction. Investors and security holders of Lam and KLA-Tencor are urged to read the joint proxy statement/prospectus and any other relevant documents that will be filed with the SEC carefully and in their entirety when they become available because they will contain important information about the proposed transaction. You may obtain copies of all documents filed with the SEC regarding this transaction, free of charge, at the SEC’s website (www.sec.gov). In addition, investors and stockholders will be able to obtain free copies of the joint proxy statement/prospectus and other documents filed with the SEC by Lam on Lam’s Investor Relations website (investor.lamresearch.com) or by writing to Lam Research Corporation, Investor Relations, 4650 Cushing Parkway, Fremont, CA 94538-6401 (for documents filed with the SEC by Lam), or by KLA-Tencor on KLA-Tencor’s Investor Relations website (ir.kla-tencor.com) or by writing to KLA-Tencor Corporation, Investor Relations, One Technology Drive, Milpitas, California 95035 (for documents filed with the SEC by KLA-Tencor). 10 KLA-Tencor Confidential - Internal Use Only

11 KLA-Tencor Confidential - Internal Use Only Participants in the Solicitation Lam, KLA-Tencor, their respective directors, and certain of their respective executive officers, other members of management and employees, may, under SEC rules, be deemed to be participants in the solicitation of proxies from Lam and KLA-Tencor stockholders in connection with the proposed transaction. Information regarding the persons who, under SEC rules, are or may be deemed to be participants in the solicitation of Lam and KLA-Tencor stockholders in connection with the proposed transaction will be set forth in the joint proxy statement/prospectus when it is filed with the SEC. You can find more detailed information about Lam’s executive officers and directors in its definitive proxy statement filed with the SEC on September 21, 2015. You can find more detailed information about KLA-Tencor’s executive officers and directors in its definitive proxy statement filed with the SEC on September 24, 2015. Additional information about Lam’s executive officers and directors and KLA-Tencor’s executive officers and directors will be provided in the above-referenced Registration Statement on Form S-4 when it becomes available.