ignature

James F. Gentilcore

POWER OF ATTORNEY

Know all by these presents, that the undersigned hereby constitutes and appoints Peter W.

Walcott the undersigned's true and lawful attorney-in-fact to:

(1) prepare, execute in the undersigned's name and on the undersigned's behalf, and submit to

the U.S. Securities and Exchange Commission (the "SEC") a Form ID, including amendments

thereto, and any other documents necessary or appropriate to obtain codes and passwords

enabling the undersigned to make electronic filings with the SEC of reports required by Section

16(a) of the Securities Exchange Act of 1934 or any rule or regulation of the SEC;

(2) execute for and on behalf of the undersigned, in the undersigned's capacity as an officer of

ENTEGRIS, INC. (the "Company"), Forms 3, 4, and 5 in accordance with Section 16(a) of the

Securities Exchange Act of 1934 and the rules thereunder, and any other forms or reports the

undersigned may be required to file in connection with the undersigned's ownership, acquisition, or

disposition of securities of the Company;

(3) 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 Forms 3, 4, or 5, or other form or report,

and timely file such form or report with the United States Securities and Exchange Commission

and any stock exchange or similar authority; and

(4) 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.

The undersigned hereby grants to 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 attorney-in-fact, is

serving in such capacity at the request of the undersigned, and is not assuming, nor is the

Company assuming, any of the undersigned's responsibilities to comply with Section 16 of the

Securities Exchange Act of 1934.

This Power of Attorney shall remain in full force and effect until the undersigned is no longer

required to file Forms 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 attorney-in-fact.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be

executed as of this 23 day of December, 2013.

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