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 ___ day of May, 2014.

Printed Name

Signature

Gregory Marshall