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Exhibit 5
HALE AND DORR LLP
COUNSELLORS AT LAW
60 STATE STREET, BOSTON, MASSACHUSETTS 02109
617-526-6000 - FAX 617-526-5000
January 29, 2001
MKS Instruments, Inc.
Six Shattuck Road
Andover, MA 01810
Re: Applied Science and Technology, Inc. 1994 Formula Stock Option Plan
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Ladies and Gentlemen:
We have assisted in the preparation of a Registration Statement on Form S-8
(the "Registration Statement") to be filed with the Securities and Exchange
Commission under the Securities Act of 1933, as amended (the "Securities Act"),
relating to an aggregate of 138,042 shares of Common Stock, no par value per
share (the "Shares"), of MKS Instruments, Inc., a Massachusetts corporation (the
"Company"), issuable under the Applied Science and Technology, Inc. 1994 Formula
Stock Option Plan (the "Plan"). The Plan was assumed pursuant to the Agreement
and Plan of Merger, dated as of October 2, 2000, by and among the Company, Mango
Subsidiary, a Delaware corporation and a wholly owned subsidiary of the Company,
and Applied Science and Technology, Inc., a Delaware corporation.
We have examined the Articles of Organization and By-Laws of the Company,
each as amended and restated to date and originals, or copies certified to our
satisfaction, of all pertinent records of the meetings of the directors and
stockholders of the Company, the Registration Statement and such other documents
relating to the Company as we have deemed material for the purposes of this
opinion.
In our examination of the foregoing documents, we have assumed the
genuineness of all signatures, the authenticity of all documents submitted to us
as originals, the conformity to original documents of all documents submitted to
us as copies, the authenticity of the originals of such latter documents and the
legal competence of all signatories to such documents.
We assume that the appropriate action will be taken, prior to the offer and
sale of the Shares in accordance with the Plan, to register and qualify the
Shares for sale under all applicable state securities or "blue sky" laws.
We express no opinion herein as to the laws of any state or jurisdiction
other than the state laws of The Commonwealth of Massachusetts, the General
Corporation Law of the State of Delaware and the federal laws of the United
States of America.
Based upon and subject to the foregoing, we are of the opinion that the
Shares have been duly authorized for issuance and, when the Shares are issued
and paid for in accordance with the terms and conditions of the Plan, the Shares
will be validly issued, fully paid and nonassessable.
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It is understood that this opinion is to be used only in connection with
the offer and sale of the Shares while the Registration Statement is in effect.
Please note that we are opining only as to the matters expressly set forth
herein, and no opinion should be inferred as to any other matters.
We hereby consent to the filing of this opinion with the Commission as an
exhibit to the Registration Statement in accordance with the requirements of
Item 601(b)(5) of Regulation S-K under the Securities Act. In giving such
consent, we do not hereby admit that we are in the category of persons whose
consent is required under Section 7 of the Securities Act or the rules and
regulations of the Commission.
Very truly yours,
/s/ Hale and Dorr LLP
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HALE AND DORR LLP