8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

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):

December 12, 2006

Cabot Microelectronics Corporation

(Exact name of registrant as specified in its charter)

Delaware	000-30205	36-4324765
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification)

870 Commons Drive, Aurora, Illinois	60504
(Address of principal executive offices)	(Zip Code)

(630) 375-6631

(Registrant’s telephone number, including area code)

Not applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o   Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o   Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o   Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o   Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 8.01Other Events

On December 12, 2006, Cabot Microelectronics Corporation issued a press release entitled “Cabot Microelectronics Announces Plans to Pursue Patent Infringement Enforcement Action against DuPont Air Products NanoMaterials LLC.” A copy of the press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

This information is being furnished pursuant to Item 8.01 of Form 8-K and shall not be deemed “filed” for purposes of Section 18 of the Securities and Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing.

Item 9.01Financial Statements and Exhibits.

(c)	Exhibits
	The following exhibit is being furnished, not filed, herewith pursuant to Item 8.01 of Form 8-K:
	99.1Press release, dated December 12, 2006, entitled “Cabot Microelectronics Announces Plans to Pursue Patent Infringement Enforcement Action against DuPont Air Products NanoMaterials LLC.”

SIGNATURE

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.

	CABOT MICROELECTRONICS CORPORATION
Date: December 12, 2006	By:	/s/ WILLIAM S. JOHNSON
		William S. Johnson
		Vice President and Chief Financial Officer
		[Principal Financial Officer]

INDEX TO EXHIBITS

Exhibit Number	Title
99.1	Press release, dated December 12, 2006, entitled “Cabot Microelectronics Announces Plans to Pursue Patent Infringement Enforcement Action against DuPont Air Products NanoMaterials LLC.”

EX-99.1

Exhibit 99.1

CABOT MICROELECTRONICS ANNOUNCES PLANS TO PURSUE PATENT INFRINGEMENT ENFORCEMENT ACTION AGAINST DUPONT AIR PRODUCTS NANOMATERIALS LLC

AURORA, IL, December 12, 2006 - Cabot Microelectronics Corporation (Nasdaq: CCMP), the leading supplier of chemical mechanical planarization (CMP) slurries to the semiconductor industry, today announced plans to pursue legal action against DuPont Air Products NanoMaterials LLC (“DA Nano”) for the manufacture and marketing of certain CMP slurries that infringe patents owned by Cabot Microelectronics. The affected DA Nano products include those used for tungsten CMP.

Cabot Microelectronics announced its plan in response to a complaint filed on December 8 by DA Nano in the United States District Court for the District of Arizona seeking declaratory relief and alleging non-infringement, invalidity and unenforceability of some of the Cabot Microelectronics patents at issue. The complaint follows Cabot Microelectronics’ refusal of DA Nano’s request to be granted a license to the Cabot Microelectronics patents raised in the complaint. Cabot Microelectronics believes that the complaint is wholly without merit and anticipates responding to it and filing a counterclaim for patent infringement shortly. DA Nano’s complaint does not allege any infringement by Cabot Microelectronics’ products of intellectual property owned by DA Nano.

“Cabot Microelectronics remains committed to the enforcement of our intellectual property and protection of our significant investment in patent-protected research and development”, stated H. Carol Bernstein, Cabot Microelectronics' Vice President, Secretary and General Counsel. “We believe certain of DA Nano’s products infringe our tungsten CMP technology, and we are disappointed that thus far they have refused to switch to non-infringing technology. We look forward to the successful resolution of this litigation.”

Earlier this year, Cabot Microelectronics successfully concluded a U.S. International Trade Commission (ITC) patent action against Cheil Industries, Inc. concerning some of the same patents currently at issue with DA Nano.

ABOUT CABOT MICROELECTRONICS CORPORATION

Cabot Microelectronics Corporation, headquartered in Aurora, Illinois, is the world's leading supplier of CMP slurries used in semiconductor and data storage manufacturing. The company's products play a critical role in the production of the most advanced semiconductor devices, enabling the manufacture of smaller, faster and more complex devices by its customers. Since becoming an independent public company in 2000, the company has grown to nearly 750 employees who work at research and development labs, sales and business offices, manufacturing facilities and customer service centers in China, France, Germany, Japan, Singapore, South Korea, Taiwan, the United Kingdom and the United States. The company's vision is to become the world leader in shaping, enabling and enhancing the performance of surfaces, and thus looks beyond its core CMP business in the semiconductor industry. For more information about Cabot Microelectronics Corporation, visit www.cabotcmp.com or contact Barbara Ven Horst, Director of Investor Relations at (630) 375-5412.

SAFE HARBOR STATEMENT

This news release may include statements that constitute “forward looking statements” within the meaning of federal securities regulations. These forward-looking statements include statements related to: future sales and operating results; company and industry growth and trends; growth of the markets in which the company participates; international events; product performance; the generation, protection and acquisition of intellectual property, and litigation related to such intellectual property; new product introductions; development of new products, technologies and markets; the acquisition of or investment in other entities; and the construction of new or refurbishment of existing facilities by Cabot Microelectronics Corporation. These forward-looking statements involve a number of risks, uncertainties, and other factors, including those described from time to time in Cabot Microelectronics’ filings with the Securities and Exchange Commission (SEC), that could cause actual results to differ materially from those described by these forward-looking statements. In particular, see “Risks Factors” in our annual report on Form 10-K for the fiscal year ended September 30, 2006, filed with the SEC. Cabot Microelectronics assumes no obligation to update this forward-looking information.