EXHIBIT 4D

                               ASECO CORPORATION

                  1993 NON-EMPLOYEE DIRECTOR STOCK OPTION PLAN
              (Amended and Restated Effective as of May 12, 1998)

         1. PURPOSE. This Non-Qualified Stock Option Plan, to be known as the
1993 Non-Employee Director Stock Option Plan (hereinafter, this "Plan") is
intended to promote the interests of Aseco Corporation (hereinafter, the
"Company") by providing an inducement to obtain and retain the services of
qualified persons who are not employees or officers of the Company to serve as
members of its Board of Directors (the "Board").

         2. AVAILABLE SHARES. The total number of shares of Common Stock, par
value $.01 per share, of the Company (the "Common Stock"), for which options may
be granted under this Plan shall not exceed 165,000 shares, subject to
adjustment in accordance with paragraph 10 of this Plan. Shares subject to this
Plan are authorized but unissued shares or shares that were once issued and
subsequently reacquired by the Company. If any options granted under this Plan
are surrendered before exercise or lapse without exercise, in whole or in part,
the shares reserved therefor shall continue to be available under this Plan.

         3. Administration. This Plan shall be administered by the Board or by a
committee appointed by the Board (the "Committee"). In the event the Board fails
to appoint or refrains from appointing a Committee, the Board shall have all
power and authority to administer this Plan. In such event, the word "Committee"
wherever used herein shall be deemed to mean the Board. The Committee shall,
subject to the provisions of the Plan, have the power to construe this Plan, to
determine all questions hereunder, and to adopt and amend such rules and
regulations for the administration of this Plan as it may deem desirable.

         4. Granting of Options.

             (a) Initial Grant. On the effective date of a registration
statement on Form S-1 covering the initial public offering of the Company's
Common Stock (the "Effective Date"), each person who is then a member of the
Board, and who is not a current or former employee or officer of the Company,
shall be automatically granted, without further action by the Board, an option
to purchase 3,000 shares of the Common Stock.

             (b) Initial Grant to New Directors. Subject to the availability of
shares under this Plan, each person who is first elected as a member of the
Board after May 15, 1996 and during the term of this Plan, and who is not on the
date of such election a current or former employee or officer of the Company,
shall be automatically granted an option to purchase 15,000

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shares of the Common Stock on the date of his or her first election as a member
of the Board.

             (c) Automatic Grants. On April 30 of each year commencing April 30,
1999 and during the term of this Plan, each person who is then serving on the
Board, and who is not a current or former employee or officer of the Company,
shall automatically be granted an option to purchase 3,500 shares of the Common
Stock, subject to the availability of shares under this Plan.

             (d) Initial Option Adjuster. On May 15, 1996, each person who is
serving on the Board as of such date, who is not a current or former employee or
officer of the Company and who is to serve on the Board following the 1996
Annual Meeting of Stockholders of the Company shall automatically be granted an
option to purchase an additional 10,000 shares of Common Stock.

         Except for the specific options referred to above, no other options
shall be granted under this Plan.

         5. Option Price. The purchase price of the stock covered by an option
granted pursuant to this Plan shall be 100% of the fair market value of such
shares on the day the option is granted. The option price will be subject to
adjustment in accordance with the provisions of paragraph 10 of this Plan. For
purposes of this Plan, if, at the time an option is granted under the Plan, the
Company's Common Stock is publicly traded, "fair market value" shall be
determined as of the last business day for which the prices or quotes discussed
in this sentence are available prior to the date such option is granted and
shall mean (i) the average (on that date) of the high and low prices of the
Common Stock on the principal national securities exchange on which the Common
Stock is traded, if the Common Stock is then traded on a national securities
exchange; or (ii) the last reported sale price (on that date) of the Common
Stock on the Nasdaq National Market System, if the Common Stock is not then
traded on a national securities exchange; or (iii) the closing bid price (or
average of bid prices) last quoted (on that date) by an established quotation
service for over-the-counter National Market System. If, at the time an option
is granted under the Plan, the Company's stock is not publicly traded, "fair
market value" shall be the fair market value on the date the option is granted
as determined by the Board in good faith.

         6. Period of Option. Unless sooner terminated in accordance with the
provisions of paragraph 8 of this Plan, an option granted hereunder shall expire
on the date which is ten (10) years after the date of grant of the option.


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         7. Vesting of Shares and Non-Transferability of Options.

             (a) Vesting. Options granted under this Plan shall not be
exercisable until they become vested. Options granted pursuant to Sections 4(b),
4(c) and 4(d) of this Plan shall vest in the optionee and thus become
exercisable immediately by the optionee in two annual installments of 50% each
on the first and second anniversary of the date of grant. Options granted
pursuant to Section 4(a) of the Plan shall be 100% vested on the date of grant
and thus be fully exercisable at any time prior to their expiration.

             (b) Legend on Certificates. The certificates representing such
shares shall carry such appropriate legend, and such written instructions shall
be given to the Company's transfer agent, as may be deemed necessary or
advisable by counsel to the Company in order to comply with the requirements of
the Securities Act of 1933 or any state securities laws.

             (c) Non-transferability. Any option granted pursuant to this Plan
shall not be assignable or transferable other than by will or the laws of
descent and distribution or pursuant to a domestic relations order and shall be
exercisable during the optionee's life time only by him or her.

         8. Termination of Option Rights.

             (a) In the event an optionee ceases to be a member of the Board for
any reason other than death or permanent disability, any then unexercised
portion of options granted to such optionee shall, to the extent not then
vested, immediately terminate and become void; any portion of an option which is
then vested but has not been exercised at the time the optionee so ceases to be
a member of the Board may be exercised, to the extent it is then vested, by the
optionee within two years of the date the optionee ceased to be a member of the
Board; and all options shall terminate after such two year period has have
expired.

             (b) In the event that an optionee ceases to be a member of the
Board by reason of his or her death or permanent disability, any option granted
to such optionee shall be immediately, and automatically accelerated and become
fully vested and all unexercised options shall be exercisable by the optionee
(or by the optionee's personal representative, heir or legatee, in the event of
death) until the scheduled expiration date of the option.

         9. Exercise of Option. Subject to the terms and conditions of this Plan
and the option agreements, an option granted hereunder shall, to the extent then
exercisable, be exercisable in whole or in part by giving written notice to the


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Company by mail or in person addressed to Aseco Corporation, 500 Donald Lynch
Boulevard, Marlboro, Massachusetts 01752, Attention: Chief Financial Officer,
stating the number of shares with respect to which the option is being
exercised, accompanied by payment in full for such shares. Payment may be (a) in
United States dollars in cash or by check, (b) in whole or in part in shares of
Common Stock of the Company already owned by the person or persons exercising
the option or shares subject to the option being exercised (subject to such
restrictions and guidelines as the Board may adopt from time to time), valued at
fair market value determined in accordance with the provisions of paragraph 5 or
(c) consistent with applicable law, through the delivery of an assignment to the
Company of a sufficient amount of the proceeds from the sale of the Common Stock
acquired upon exercise of the option and an authorization to the broker or
selling agent to pay that amount to the Company, which sale shall be at the
participant's direction at the time of exercise. There shall be no such exercise
at any one time as to fewer than one hundred (100) shares or all of the
remaining shares then purchasable by the person or persons exercising the
option, if fewer than one hundred (100) shares. The Company's transfer agent
shall, on behalf of the Company, prepare a certificate or certificates
representing such shares acquired pursuant to exercise of the option, shall
register the optionee as the owner of such shares on the books of the Company
and shall cause the fully executed certificates(s) representing such shares to
be delivered to the optionee as soon as practicable after payment of the option
price in full. The holder of an option shall not have any rights of a
stockholder with respect to the shares covered by the option, except to the
extent that one or more certificates for such shares shall be delivered to him
or her upon the due exercise of the option.

         10. Adjustments Upon Changes in Capitalization and Other Matters. Upon
the occurrence of any of the following events, an optionee's rights with respect
to options granted to him or her hereunder shall be adjusted as hereinafter
provided:

             (a) If, after January 18, 1993, the shares of Common Stock shall be
subdivided or combined into a greater smaller number of shares or if the Company
shall issue any shares of Common Stock as a stock dividend on its outstanding
Common Stock, the number of shares of Common Stock deliverable upon the exercise
of options shall be appropriately increased or decreased proportionately, and
appropriate adjustments shall be made in the purchase price per share to reflect
such subdivision, combination or stock dividend. No adjustment, however, shall
be made for the 1-for-2.4 reverse split of the Common Stock declared by the
Board on January 18, 1993.

             (b) Merger; Consolidation; Liquidation; Sale of Assets. In the
event the Company is merged into or consolidated


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with another corporation under circumstances where the Company is not the
surviving corporation and in the event the acquiring corporation or its parent
assumes the Plan, upon the effective date of any such merger or consolidation,
as the case may be, each holder of an outstanding option shall be entitled, upon
exercise of such option, to receive in lieu of shares of Common Stock, shares of
such stock or other securities as the holders of shares of Common Stock
received pursuant to the terms of the merger or consolidation; provided,
however, that any holder of such an option shall be required to exercise such
option within six months after the effective date of such merger.

             (c) Issuance of Securities. Except as expressly provided herein, no
issuance by the Company of shares of stock of any class, or securities
convertible into shares of stock of any class, shall affect, and no adjustment
by reason thereof shall be made with respect to, the number or price of shares
subject to options. No adjustments shall be made for dividends paid in cash or
in property other than securities of the Company.

             (d) Adjustments. Upon the happening of any of the foregoing events,
the class and aggregate number of shares set forth in paragraph 2 of this Plan
that are subject to options which previously have been or subsequently may be
granted under this Plan shall also be appropriately adjusted to reflect such
events. The Board shall determine the specific adjustments to be


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made under this paragraph 10 and its determination shall be conclusive.

         11. Restrictions on Issuance of Shares. Notwithstanding the provisions
of paragraphs 4 and 9 of this Plan, the Company shall have no obligation to
deliver any certificate or certificates upon exercise of an option until one of
the following conditions shall be satisfied:

                  (i) The shares with respect to which the option has been
         exercised are at the time of the issue of such shares effectively
         registered under applicable Federal and state securities laws as now in
         force or hereafter amended; or

                  (ii) Counsel for the Company shall have given an opinion that
         such shares are exempt from registration under Federal and state
         securities laws as now in force or hereafter amended; and the Company
         has complied with all applicable laws and regulations with respect
         thereto, including without limitation all regulations required by any
         stock exchange upon which the Company's outstanding Common Stock is
         then listed.

         12. Representation of Optionee. If requested by the Company, the
optionee shall deliver to the Company written representations and warranties
upon exercise of the option that are necessary to show compliance with Federal
and state securities laws, including representations and warranties to the
effect that a purchase of shares under the option is made for investment and not
with a view to their distribution (as that term is used in Securities Act of
1933).

         13. Option Agreement. Each option granted under the provisions of this
Plan shall be evidenced by an option agreement, which agreement shall be duly
executed and delivered on behalf for the Company and by the optionee to whom
such option is granted. The option agreement shall contain such terms,
provisions and conditions not inconsistent with this Plan as may be determined
by the officer executing it.

         14. Termination and Amendment of Plan. Options may no longer be granted
under this Plan after January 18, 2003, and this Plan shall terminate when all
options granted or to be granted hereunder are no longer outstanding. The Board
may at any time terminate this Plan or make such modification or amendment
thereof as it deems advisable; provided, however, that the Board may not,
without approval by the affirmative vote of the holders of a majority of the
shares of Common Stock present in person or by proxy and entitled to vote at the
meeting, (a)


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increase the maximum number of shares for which options may be granted under
this Plan (except by adjustment pursuant to Section 10), (b) materially modify
the requirements as to eligibility to participate in this Plan, (c) materially
increase benefits accruing to option holders under this Plan, or (d) amend this
Plan in any manner which would cause Rule 16b-3 to become inapplicable to this
Plan; and provided further that the provisions of this Plan specified in Rule
16b-3(c)(2)(ii)(A) (or any successor or amended provision thereof) under the
Securities Exchange Act of 1934 (including without limitation, provisions as to
eligibility, amount, price and timing of awards) may not be amended more than
once every six months, other than to comport with changes in the Internal
Revenue Code, the Employee Retirement Income Security Act, or the rules
thereunder. Termination or any modification or amendment of this Plan shall not,
without consent of a participant, affect his or her rights under an option
previously granted to him or her.

         15. Withholding of Income Taxes. Upon the exercise of an option, the
Company, in accordance with Section 3402(a) of the Internal Revenue Code, may
require the optionee to pay withholding taxes in respect of amounts considered
to be compensation includible in the optionee's gross income.

         16. Compliance with Regulations. It is the Company's intent that the
Plan comply with all respects with Rule 16b-3 under the Securities Exchange Act
of 1934 (or any successor or amended version thereof) and any applicable
Securities and Exchange Commission interpretations thereof. If any provision of
this Plan is deemed not to be in compliance with Rule 16b-3, the provision shall
be null and void.

         17. Governing Law. The validity and construction of this Plan and the
instruments evidencing options shall be governed by the laws of The Commonwealth
of Massachusetts, without giving effect to the principles of conflicts of law
thereof.

Date Approved by Board of
Directors of the Company:                May 12, 1998

Date Approved by Stockholders
of the Company:                          August 11, 1998


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