<PAGE>   1
                                                                   EXHIBIT 10.58

                                 (Translation)

                              Loan Agreement Deed


     This document certifies that the Japan Development Bank (hereinafter
referred to as the "Bank") has loaned the funds set forth in the following
summary of loans (hereinafter referred to as the "Summary") to Watkins-Johnson
International Japan K.K. (hereinafter referred to as the "Borrower"), and that
the Borrower has acknowledged both the Summary and the terms and conditions set
forth in the Annex (hereinafter referred to as the "Conditions"), and that the
Borrower has received such funds.

     The execution, validity, interpretation and performance of this Agreement
shall be governed by the laws of Japan.

     IN WITNESS WHEREOF, the parties hereto have executed one original of this
Agreement in Japanese, and the Bank shall keep the original and the Borrower
shall keep a copy thereof respectively.

Dated: June 12, 1996


                                         A: The Japan Development Bank
                                             9-1, Otemachi 1-chrome
                                             Chiyoda-ku, Tokyo

                                             (stamp signature and seal)
                                             --------------------------
                                              Yoshihiko Yoshino
                                              Governor


                                         B: Watkins-Johnson International
                                             Japan K.K.
                                             D-842, 2-1, Sakado 3-chrome
                                             Takatsu-ku, Kawasaki, Kanagawa

                                             (stamp signature and seal)
                                             --------------------------
                                              Stephen E. Chelberg
                                              Representative Director
<PAGE>   2
                                Summary of Loans

Principal:     One Billion Three Hundred Fifty Million Yen
               (Y1,350,000,000)

Name of and expenses for the project for which the loan is required (hereinafter
referred to as the "Project"):

     Construction of Technology Center for Semiconductor-Manufacturing Equipment
     Two Billion Seven Hundred Million Yen (Y2,700,000,000)

Repayment of the principal:

     The full repayment shall be made on the 28th day of November, 2006.

Interest rate:

     Three point one percent (3.1%) per annum (subject to per diem calculation
on the basis of 365 days per year).

Method of payment of interest:

     The first payment shall be made on the 28th day of November, 1996, and
thereafter payment shall be made on the 28th day of May and November of each
year. Interest accrued between each payment date shall be paid at the end of
the accrual period.

<PAGE>   3

ANNEX


                              Terms and Conditions

(Purpose of the Borrowed Funds)

Article 1.

      The Borrower shall perform the Project in accordance with the Project plan
as it exists as of the date of this Agreement and shall use the borrowed money
under this Agreement only for such Project.

(Installment Schedule for Payment of the Borrowed Funds)

Article 2.

      The Borrower shall initially keep the borrowed funds under this Agreement
on deposit with the Bank and the Bank shall deliver such deposited funds
(hereinafter referred to as the "Deposited Funds") to the Borrower in
installments based upon the progress of the Project, the payment of expenses for
the Project and related matter.

      2.  When the Borrower withdraws the Deposited Funds from the Bank, the
Borrower shall, in advance, notify the Bank of such payment of expenses for the
Project and other related matters in a form prescribed by the Bank and shall
obtain the Bank's consent to such withdrawal.

      3.  The Bank shall pay no interest on the Deposited Funds to the Borrower,
and the Borrower shall pay no interest on the borrowed money up to the amount
of the Deposited Funds in the Bank.

      4.  The Borrower shall not assign or create a pledge on



<PAGE>   4
the right to deliver the Deposited Funds to a third party.


(Delivery of the Deposited Funds by Bank Transfer)

Article 3.

        If the Bank delivers the Deposited Funds under this Agreement by
transfer to the Borrower's bank account, then the delivery of the Deposited
Funds to the Borrower shall be deemed to be fulfilled upon completion of the
Bank's procedure requesting the transfer of the Deposited Funds to the
Borrower's bank account. Even if the Borrower thereafter suffers a loss for
reasons including but not limited to accidents or procedural delays which occur
after completion of the Bank's procedure and for which the Bank is not
responsible, the Borrower shall not then demand compensation from or make other
claims on the Bank.

(Repayment of the Obligations by Bank Transfer)

Article 4.

        If the Borrower repays its obligations by transfer to the Bank's account
with checks, notes or other securities (hereinafter collectively referred to as
"Securities"), the Borrower shall then ensure that the Securities are paid in
full by the due dates of the Borrower's obligations.


(Repayment of the Obligations by Delivering Securities)

Article 5.

        If the Borrower repays its obligations by delivering the Securities to
the Bank, such Securities shall be negotiable

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for settlement through the clearing house consented to by the Bank and the
Borrower shall ensure that the Securities are paid in full by the due dates of
the Borrower's obligations.

     2. If any of the Securities in the preceding paragraph is dishonored and
returned to the Borrower by the Bank, then the Borrower agrees that the Bank is
not responsible for taking any steps to preserve any rights relating to such
Securities.

(Prepayment)

Article 6.

     If the expenses for the Project decrease to less than those set forth in
the Summary (hereinafter referred to as the "Summary Amount") because of a
change in the Project plan or other reasons, and the Bank so requests, the
Borrower shall then, notwithstanding the maturity date of the loan set forth in
the Summary, prepay the borrowed money under this Agreement in proportion equal
to the percentage of the reduction of the Summary Amount.

     2. If the Bank finds that the fulfillment of the Project's aim is rendered
impracticable because the decreased amount referred to in the preceding
paragraph amounts to a substantial percentage of the Summary Amount, and the
Bank so requests, the Borrower shall then prepay the borrowed money received
under this Agreement in full.

     3. If (i) the Borrower does not perform the Project without a justifiable
reason, despite the Bank's instructions, even after a reasonable period which
the Bank has deemed
<PAGE>   6
necessary for performance of the Project, or (ii) if the Borrower does not apply
the money delivered under paragraph 1 of Article 2 to satisfy the payments due
for the expenses of the Project, or (iii) if the Bank finds that the purpose of
the Project will not be completed on the ground that the Borrower has assigned
or leased an object which the Borrower obtained as a result of the Project to a
third party immediately after the Borrower obtained it or for other reasons and
the Bank so requests, the Borrower shall then, notwithstanding the maturity date
set forth in the Summary, prepay the borrowed money received under this
Agreement to the Bank either in whole or in part.

     4.   The Borrower may prepay the borrowed money under this Agreement in
whole or in part with the Bank's prior consent.

     5.   In addition to the preceding paragraph, the Borrower may prepay the
borrowed money under this Agreement in whole or in part by giving the Bank
written notice of prepayment at least ninety (90) days prior to the date of
prepayment.

     6.   In case the preceding paragraph applies, the Borrower may not cancel
the prepayment without the Bank's consent after the Bank's receipt of such
prepayment notice.

Article 7.

     When the Borrower prepays the borrowed money, the Borrower shall pay the
amounts sets forth in each of the following upon such prepayment:

     (1) Interest on the prepaid amount accrued up until the
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date of such prepayment.

     (2) In case of the prepayment arising under paragraph 5 of the preceding
Article, if the interest rate under this Agreement (hereinafter referred to as
the "Agreed Interest Rate") exceeds the Bank's standard interest rate as of the
date of such prepayment (hereinafter referred to as the "Standard Interest
Rate"), in addition to the preceding item, the difference between (i) the amount
equal to interest which is calculated on the basis of the Agreed Interest Rate
on the prepaid amount for the period during the date of such prepayment and the
maturity date set forth in the Summary and (ii) the amount equal to interest
which is calculated on the basis of the Standard Interest Rate for the same
period (with the method of such calculation to be determined by the Bank).

Article 8.

     The Bank may set off the Deposited Funds against any funds, including
interest thereon and any other obligation pertaining to such funds, which the
Borrower should prepay.

(Appropriation of Repayment)

Article 9.

     (i) If the Borrower prepays the borrowed money under this Agreement to the
Bank in part, or (ii) if the Bank sets off the Deposited Funds against the
funds which the Borrower should prepay under this Agreement, or (iii) if the
amount of the repayment of obligations under this Agreement or under other loan
agreements between the Bank and the Borrower is


<PAGE>   8
less than the amount which the Borrower should repay under such agreements,
then the Bank may appropriate the amount due in such manner as decided upon by
the Bank.

(Inspection of Books, Etc.)

Article 10.

     The Bank may at any time inspect the status of the Project as well as the
Borrower's assets, documents, books and other materials as the Bank deems
necessary based on reasonable grounds, such as to confirm the use of the loaned
funds under this Agreement or for the preservation of the Bank's rights.

     2. The Borrower shall offer assistance as needed to the Bank for the
inspection set forth in the preceding paragraph.

(Matters to be Filed)

Article 11.

     If the Borrower changes its name, corporate name, address, representative,
filed seal or other matters filed with the Bank, the Borrower shall then notify
the Bank thereof in writing forthwith.

(Matters to be Reported)

Article 12.

     The Borrower shall report to the Bank, in accordance with the method as
instructed by the Bank, the matters mentioned in (1) and (2) below upon the
Bank's request and the matter mentioned in (3) below without delay upon the
occurrence of
<PAGE>   9


such event.

      (1)    Progress status of the Project and payment status of the expenses
of the Project.

      (2)    Each settlement of account (including mid-year settlements if the
company/companies which choose(s) yearly settlement make(s) such a mid-year
settlement) and decisions as to dividends (including interim dividends) of the
Borrower and Watkins Johnson Company (hereinafter referred to as the
"Guarantor").

      (3)    Other important events concerning management, finance or business.


(Acceleration of Payment)

Article 13.

      If any one of the following events should occur and be continuing, and the
Bank so requests, the Borrower's obligations to the Bank shall then immediately
become due and payable and the Borrower shall forthwith pay the entire amount of
its obligations under this Agreement.

      (1) When the Borrower does not perform the Project and uses the borrowed
money under this Agreement for a purpose other than that of the Project;

      (2) When the Borrower fails to perform any of its obligations under
Articles 11 or 12 and continues not to perform such obligations despite the
Bank's request, or when the Borrower makes a false statement or report
thereunder;

      (3) When the Borrower fails to pay any part of the principal or interest
under this Agreement;



<PAGE>   10
     (4) When the Borrower fails to perform any of its obligations under this
Agreement other than those set forth in each of the preceding items, or fails
to perform any of its obligations to the Bank under any other agreements;

     (5) When the Borrower dishonors any note or check;

     (6) When an order or notice of provisional attachment, preservative
attachment or attachment with respect to the Deposited Funds is issued or given
to the Borrower;

     (7) When attachment with respect to assets which the Borrower furnishes or
agrees to furnish to the Bank as security is made;

     (8) When the Borrower or the Guarantor stops payment or an application is
filed by or against the Borrower or the Guarantor for bankruptcy, composition,
corporate reorganization or corporate arrangement;

     (9) When the Borrower or the Guarantor is dissolved or its business is
closed;

     (10) When any event reasonably requiring the preservation of the Bank's
rights other than those set forth in each of the preceding items occurs to the
Borrower;

     (11) When the Guarantor fails to perform any of its obligations under the
guaranty agreement with the Bank dated June 12, 1996 (hereinafter referred to
as the "Guaranty Agreement" in this Article) and, if the Bank reasonably
determines that such failure can be cured, such failure to perform such
obligation continues unremedied for a period of thirty (30) days; or

     (12) When any event of default occurs under or in
<PAGE>   11
connection with any obligation of the Guarantor to the Bank other than those
incurred under the Guaranty Agreement.

(Security)

ARTICLE 14.

     The Borrower shall, upon a request by the Bank based on reasonable and
probable cause to preserve the Bank's rights under this Agreement, furnish the
Bank with security or additional security as may be approved by the Bank,
whether or not there is any security or a guarantor under this Agreement or any
other agreements.

(Execution of Notarial Deed)

ARTICLE 15.

     The Borrower shall, at any time upon the Bank's request (with the
Guarantor, if the Bank so instructs), commission a notary public in Japan and
take all necessary actions to execute a notarial deed containing an
acknowledgement of the obligations under this Agreement and a statement of
acceptance of enforcement thereof.

(Burden of Expenses)

ARTICLE 16.

     The Borrower shall bear any expenses for preparation of this Agreement,
registration, and all other expenses in connection with the performance of this
Agreement.
<PAGE>   12
(Post Default Interest)

ARTICLE 17.

     The Borrower shall pay post default interest equivalent to 14.5% per annum
(subject to per diem calculation on the basis of 365 days per year) on the
principal, interest and any other amounts payable in the event of default of
any payment obligation, or on advance money the Bank paid for the expenses under
the preceding Article.

(Court Jurisdiction)

ARTICLE 18.

     In the event of any litigation or controversies in connection with this
Agreement, the Borrower hereby submits and consents to the non-exclusive
jurisdiction of the Tokyo District Court.
<PAGE>   13
                               GUARANTY AGREEMENT

                                                                    July 6, 1999


To:  Mr. Masami Kogayu, Governor
     The Japan Development Bank

     The undersigned (hereinafter referred to as the "Guarantor"), after having
accepted the following terms and conditions, hereby guarantees all the
obligations of Watkins-Johnson International Japan K.K. (hereinafter referred
to as the "Debtor") to the Japan Development Bank (hereinafter referred to as
the "Bank") arising out of those certain agreements made by and between the
Bank and the Debtor dated June 12, 1996 and December 26, 1997 (hereinafter
referred to as the "Original Agreements"), certain basic provisions of which
are more fully described in Attachment A.

ARTICLE 1.

     The Guarantor hereby confirms the obligations of the Debtor under the
Original Agreements, and agrees to each article and paragraph of the Original
Agreements.

ARTICLE 2.

     1.   The Guarantor, as primary obligor and not as surety only, shall be
jointly and severally responsible with the Debtor (this Guaranty being
Rentalhosho under the laws of Japan) for the full and prompt payment to the
Bank of the entire amount of the Debtor's obligations under, and in accordance
with the terms of, the Original Agreements. Even if any change or amendment is
made to either of the Original Agreements, the Guarantor shall perform its
guaranty obligations in accordance with the Debtor's obligations as changed
thereby.

     2.   The Guarantor shall not claim any exemption from its obligations
hereunder even if there occurs any increase, decrease, replacement, release of,
or any other change with respect to the security or the guaranty described in
the Original Agreements.

ARTICLE 3.

     In the event the Guarantor performs its guaranty obligations, any rights
it acquires from the Bank by virtue of subrogation shall not be exercised
without the Bank's consent until the Debtor has paid in full all of its
obligations to the Bank under the Original Agreements, as it may be amended
from time to time. Further, upon the Bank's request, such rights or ranking
thereof shall be assigned to the Bank free of charge and all the procedures
required therefor shall be taken.
<PAGE>   14
Article 4.

     On or prior to the date of the execution of this Guaranty Agreement, the
Bank shall have confirmed that the Guarantor is able to provide the documents
listed in Attachment B and has executed those documents to which it is a party;
and all such documents shall be dated the date of the execution of this
Guaranty Agreement and shall otherwise be in form and substance satisfactory to
the Bank. In any event, the Bank shall have received the originals of such
documents at its Tokyo head office by a date to be designated by the Bank.

Article 5.

     If any change occurs in the name, the authorized signatories (including
the specimen signature(s) thereof), the address, or any other reported matters
of the Guarantor, notification thereof shall immediately be given to the Bank
in writing, and such change shall become effective upon receipt thereof by the
Bank.

Article 6.

     All expenses incurred in the preparation of this Guaranty Agreement and
all other expenses otherwise incurred in connection with this Guaranty
Agreement shall be borne by the Guarantor.

Article 7.

     1.   This Guaranty Agreement shall be deemed to be a contractual
obligation under, and shall be governed by and construed and interpreted in
accordance with, the laws of Japan.

     2.   In the event of any litigation pertaining to this Guaranty Agreement,
the Guarantor hereby submits and consents to the non-exclusive jurisdiction of
the Tokyo District Court. The Guarantor hereby irrevocably appoints
Watkins-Johnson International Japan K.K., 12-7-2, Kuriki, Asao-ku,
Kawasaki-shi, Japan as its agent to receive service of process in Japan in
connection with any suit, action or proceeding relating to this Guaranty
Agreement. In the event that agent ceases to be able to act as agent of the
Guarantor hereunder or ceases to have an office in Tokyo, Japan and the
Guarantor fails to appoint a successor agent acceptable to the Bank, the
Guarantor agrees that the Bank shall automatically serve as its agent to
receive service of process in Japan.

Article 8.

     The Guarantor agrees that this Guaranty Agreement shall be binding upon it
and its successors and assigns and may not be assigned without the prior
written consent of the Bank.

Article 9.

     This Guaranty Agreement shall be prepared in English.



                                      -2-
<PAGE>   15


                                        SILICON VALLEY GROUP, INC.


                                        By: /s/ RUSSELL G. WEINSTOCK
                                          -----------------------------------

                                        Name:  Russell G. Weinstock
                                             --------------------------------

                                        Title:  V.P. of Finance & CFO
                                              -------------------------------

                                        Address:  101 Metro Drive, Suite 400
                                                -----------------------------

                                                  San Jose, CA 95110
                                                -----------------------------









                                      -3-
<PAGE>   16
                                  ATTACHMENT A

                   DESCRIPTION OF THE ORIGINAL AGREEMENTS AND
                        SUMMARY OF BORROWING CONDITIONS

The Original Agreement dated June 12, 1996

     Parties: The Japan Development Bank and Watkins-Johnson International
Japan K.K.

Summary of the Borrowing Conditions thereof

1)   Principal: Yen 1,350,000,000

2)   Project for which the loan is required: Construction of Technology Center
     for Semiconductor Manufacturing Equipment

3)   Repayment schedule of principal:
     The repayment shall be made in full on the 28th day of November 2006

4)   Interest rate:
     3.1% per annum (subject to per diem calculation on the basis of 365 days a
     year.)

5)   Method of payment of interest:
     The first payment shall be made on the 28th day of November 1996 and
     thereafter payment shall be made on the 28th day of May and November of
     every year. Interest accrued between each payment day shall be paid at the
     end of the accrual period.
<PAGE>   17
                                  ATTACHMENT B

                      Documents Required Under Article 4.

1. Copies, certified by a duly authorized officer of the Guarantor, of the
   Guarantor's articles of incorporation and by-laws.

2. Copies, certified by a duly authorized officer of the Guarantor, of a
   resolution of the board of directors of the Guarantor approving and
   authorizing the execution, delivery, and performance of the Guaranty
   Agreement by the Guarantor and authorizing specified officer(s) and/or other
   representative(s) of the Guarantor to execute and deliver the Guaranty
   Agreement on behalf of the Guarantor.

3. A certificate signed by a duly authorized officer of the Guarantor as to the
   incumbency of those officers or other representatives of the Guarantor
   authorized to sign the Guaranty Agreement and certifying the specimen
   signatures of such persons.

<PAGE>   18
                                                                   June 25, 1999



Watkins-Johnson Company
3333 Hillview Avenue
Palo Alto, California 94304-1223

Silicon Valley Group, Inc.
101 Metro Drive, Suite 400
San Jose, California 95110

Ladies and Gentlemen:

This letter is in reference to the letter (the "Letter") dated June 25, 1999
from Silicon Valley Group, Inc. ("SVG") and Watkins-Johnson Company ("WJ
Company").

We understand that the cancellation of the guaranty agreements with WJ Company
listed in the Letter (the "Old Guaranty Agreement") and the release of all WJ
Company's obligations thereunder are conditions precedent to the closing (the
"Closing") of the Acquisition set forth in the Letter. We hereby confirm and
agree that the guaranty agreement between THE JAPAN DEVELOPMENT BANK ("JDB") and
SVG (the "New Guaranty Agreement"), which has been executed by JDB and SVG, will
come into effect upon the completion of the Closing and, if the Closing fails to
occur on or prior to July 15, 1999 (the "Termination Date"), will be
automatically cancelled and will then never come into effect.

Based upon the foregoing understanding, JDB hereby irrevocably agrees to issue
and deliver the release letter in the same form as attached hereto to WJ Company
immediately following the completion of the Closing. JDB's agreement to issue
and deliver the release letter will become null and void if the Closing fails to
occur on or prior to the Termination Date.

                                THE JAPAN DEVELOPMENT BANK



                                By /s/ YASUGHI NISHIMURA
                                -----------------------
                                Name: Yasughi Nishimura
                                -----------------------
                                Title: Director of the Japan Development Bank
                                ---------------------------------------------
<PAGE>   19
Acknowledged and agreed:

Watkins-Johnson Company



By /s/ W. KEITH KENNEDY JR
   -----------------------
   Name: W. Keith Kennedy Jr.
         --------------------
   Title: President
         --------------------
   Date:
         --------------------

Silicon Valley Group, Inc.



By
  ---------------------------
  Name:
       ----------------------
  Title:
       ----------------------
  Date:
       ----------------------

<PAGE>   20
Acknowledged and agreed:

Watkins-Johnson Company



By
  ---------------------------------
  Name:
       ----------------------------
  Title:
        ---------------------------
  Date:
        ---------------------------



Silicon Valley Group, Inc.

By /s/ RUSSELL G. WEINSTOCK
  ---------------------------------
  Name: Russell G. Weinstock
       ----------------------------
  Title: VP of Finance & CFO
        ---------------------------
  Date:  7/1/99
        ---------------------------