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                                                                     Exhibit 8.1

                                February 3, 1999

SpeedFam International, Inc.
305 North 54th Street
Chandler, Arizona  85226

Gentlemen:

         We have acted as tax counsel to SpeedFam International, Inc., an
Illinois corporation ("SpeedFam"), and SpeedFam, Inc., a wholly-owned subsidiary
of SpeedFam incorporated in Delaware ("Merger Sub"), in connection with the
Agreement and Plan of Merger (the "Merger Agreement"), dated as of November 19,
1998 by and among SpeedFam, Merger Sub, and Integrated Process Equipment Corp.,
a Delaware corporation ("IPEC"). Pursuant to the Merger Agreement, SpeedFam will
form Merger Sub. Merger Sub will then be merged with and into IPEC (the
"Merger"). As a result of the Merger, IPEC will become a wholly-owned subsidiary
of SpeedFam. IPEC stockholders will receive SpeedFam stock in exchange for their
IPEC stock in the Merger. All capitalized terms not defined herein have the
meaning set forth in the Merger Agreement. All section references herein are to
the Internal Revenue Code of 1986 as amended (the "Code") or to the regulations
promulgated thereunder.

         You have requested our opinion regarding certain federal income tax
consequences of the Merger in accordance with Section 6.1 of the Merger
Agreement. In rendering this opinion, we have examined original, certified
copies or copies otherwise identified to our satisfaction as being true copies
of the originals of the following documents (including all exhibits and
schedules attached thereto):

                   (a) the Merger Agreement;

                   (b) the certificates of representations of SpeedFam and IPEC,
         attached hereto as Exhibits A and B (the "Certificates of
         Representations");

                   (c) the Registration Statement on Form S-4 filed with the
         Securities and Exchange Commission (which contains a prospectus and
         joint proxy statement of SpeedFam and IPEC);

                   (d) the letters and reports delivered by Lehman Brothers and
         Morgan Stanley & Co., Inc. as described in Section 3.21 of the Merger
         Agreement; and

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                   (e) such other instruments and documents related to the
         formation, organization, and operation of SpeedFam, Merger Sub, and
         IPEC related to the consummation of the Merger and the transactions
         contemplated thereby as we have deemed necessary and/or appropriate.

         In rendering this opinion, we have assumed, without any independent
investigation, the following:

                  (aa) the authenticity of original documents, the conformity to
         original documents of all documents submitted to us as copies, and the
         genuineness of all signatures, and the due execution and delivery of
         all documents where due execution and delivery are a prerequisite to
         the effectiveness thereof;

                  (bb) the truth and accuracy, at all relevant times, of all
         representations, warranties, and statements made, or to be made, by
         SpeedFam, Merger Sub, and IPEC, and their managements and stockholders,
         in connection with the Merger, in the Merger Agreement (including any
         Exhibits thereto), and the Certificates of Representations;

                  (cc) no outstanding indebtedness of SpeedFam represents equity
         for tax purposes, no outstanding equity of SpeedFam represents
         indebtedness for tax purposes;

                  (dd) the Merger will be effected pursuant to applicable state
         laws, and in accordance with the Merger Agreement;

                  (ee) SpeedFam has no outstanding equity interest other than
         shares of SpeedFam common stock.

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OPINION

         Based on our examination of the foregoing items and subject to the
limitations, qualifications, assumptions, and caveats set forth herein, we are
of the opinion that:

                  (i) the Merger will be a reorganization within the meaning of
         Sectiona368(a) of the Code; and

                  (ii) the discussion in the Registration Statement entitled
         "Material Federal Income Tax Considerations" accurately summarizes the
         material federal income tax consequences of the Merger.

LIMITATION ON RELIANCE ON THIS OPINION

         This opinion does not address the various state, local, or foreign tax
consequences that may result from the Merger. In addition, no opinion is
expressed as to any federal income tax consequences of the Merger except as
specifically set forth herein, and this opinion may not be relied upon except
with respect to the consequences specifically discussed herein. In particular,
we express no opinion regarding the application of Section 83 of the Code to
options to acquire stock of any of the parties, and particularly, the continued
application of Section 83 of the Code to any options exchanged for options to
acquire stock of another Party to the Merger.

         This opinion addresses only the Merger as described in the Merger
Agreement and does not extend to any other transaction described in the Merger
Agreement. To the extent any of the representations, warranties, statements, and
assumptions material to our opinion and upon which we have relied are not
complete, correct, true, and accurate, our opinion would be adversely affected
and cannot be relied upon.

         This opinion only represents our best judgment as to the federal income
tax consequences of the Merger and is not binding on the Internal Revenue
Service or the courts. The conclusions are based on the Code, existing judicial
decisions, administrative regulations, and published rulings. No assurance can
be given that the future legislative, judicial, or administrative changes would
not adversely affect the accuracy of the conclusions stated herein. By rendering
this opinion, we undertake no responsibility to advise you of any new
developments in the application or interpretation of the federal income tax
laws.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to our Firm made therein under the
caption "Legal Matters." In giving such consent, we do not admit that we come
within the category of persons whose consent is required

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under Section 7 of the Securities Act or the rules and regulations of the
Commission promulgated thereunder.

                                      Respectfully submitted,

                                      Chapman and Cutler