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                                                                     EXHIBIT 5.1





                                 May 5, 1997


Silicon Valley Group, Inc.
2240 Ringwood Avenue
San Jose, CA  95131

         Re:      Registration Statement on Form S-8

Ladies and Gentlemen:

         We have examined (i)the Registration Statement on Form S-8 to be filed
by Silicon Valley Group, Inc. (the "Company" or "you") with the Securities and
Exchange Commission on or about May 5, 1997 (the "Registration Statement") in
connection with the registration under the Securities Act of 1933, as amended
(the "Act"), of 1,500,000 shares of your Common Stock (the "Shares") under the
Company's 1996 Stock Plan (the "Plan") and (ii) the Prospectus dated May 5,
1997 that relates to the Plan and to such Registration Statement pursuant to
Rule 428(a)(i) under the Act. As your legal counsel in connection with this
transaction, we have examined the proceedings taken and are familiar with the
proceedings proposed to be taken by you in connection with the issuance and sale
of the Shares pursuant to the Plan.

         It is our opinion that, upon completion of the actions being taken, or
contemplated by us as your counsel to be taken by you prior to the issuance of
the Shares pursuant to the Registration Statement and the Plan, and upon
completion of the actions being taken in order to permit such transactions to be
carried out in accordance with the securities laws of the various states where
required, the Shares will be legally and validly issued, fully-paid and
non-assessable.

         We consent to the use of this opinion as an exhibit to the Registration
Statement, and further consent to the use of our name wherever appearing in the
Registration Statement and any amendments thereto.

                                       Very truly yours,
                                     
                                       WILSON SONSINI GOODRICH & ROSATI
                                       Professional Corporation
                                     
                                       /s/ Wilson, Sonsini, Goodrich & Rosati