<PAGE>

                                                             Wallace E. Breitman
                                             Sr. Vice President, Human Resources
                                           Telephone:               858-385-6521
                                                 Fax:               858-385-6061
                                              E-mail:        wbreitman@cymer.com


May 4, 2000

Brian C. Klene
72 Farrer Road
Belmont #05-04, Gallop Gables
Singapore 268851

Dear Brian:

It is my pleasure to offer you the position of Senior Vice President,
Marketing and Business Development, for Cymer, Inc. This position reports to
the President, Cymer, Inc. Cymer's dynamic environment will offer you both
challenges and opportunities. All who have met you are very impressed with
your qualifications and potential, and believe you can make a significant
contribution to our future success. The specific terms of our offer to you
are:

BASE SALARY:         Your initial base salary will be $8,269.23 bi-weekly,
                     the equivalent of $215,000.00 per year. You will receive
                     a performance-based merit review in January of each year.

START DATE:          We would like you to begin work on as soon as possible,
                     on a date mutually agreed upon by you and the President.

SIGN-ON BONUS:       You will be granted a Sign-on bonus of $100,000.00 net.
                     This bonus will be paid to you in your first regular
                     paycheck. In the event your employment terminates within
                     one year of your start date, you will be required to
                     repay the prorated bonus amount.

INCENTIVE BONUS:     You will be eligible to participate in the Cymer 2000
                     Executive Incentive Bonus Plan. Your annual target bonus
                     will be 80.0% of your base salary. The bonus parameters
                     are: 33.3% is based on the company achieving its annual
                     net profit target; 33.3% is based on the company
                     achieving its annual revenue target; and 33.3% is based
                     on your achieving specific MBOs to be determined between
                     you and the president after you begin work. Your year
                     2000 bonus payments will be based on your actual base
                     payroll. In addition, you will be eligible for a 5.0%
                     Profit Sharing Bonus if the Company achieves its 2000
                     revenue and operating profit targets. Both Bonus and
                     Profit Sharing, if paid, will be based on your actual
                     2000 Cymer base payroll.

STOCK OPTION:        Subject to the approval of the Compensation Committee of
                     the Board of Directors, you will be granted the approval
                     to acquire 150,000 shares of Cymer Common Stock in
                     accordance with the Company's 1996 Stock Option Plan.
                     The request will be presented to the Committee for
                     action at its first regular meeting after you have
                     become an employee of the Company. The exercise price of
                     the option will be the closing market price on the date
                     you join Cymer. Vesting of your options will be as
                     follows:
                     a)  35,000 options will be 100% vested at the close of
                     your first day of employment;
                     b)  15,000 options will be 100% vested after three (3)
                     months of employment;
                     c)  100,000 shares will vest per the Company's normal
                     vesting schedule over four years, twenty-five percent
                     vesting after one year of service, and one forty-eighth
                     (1/48) vesting monthly thereafter.

                                           Page 1 of 3

<PAGE>


                                                             Wallace E. Breitman
                                             Sr. Vice President, Human Resources
                                           Telephone:               858-385-6521
                                                 Fax:               858-385-6061
                                              E-mail:        wbreitman@cymer.com


RELOCATION:          We recognize that your move to San Diego will require
                     some effort and expense. To help offset these
                     expenditures, you will be paid a net Relocation Bonus of
                     up to two months base salary, to be paid not later than
                     the end of your first week of work. A Taxability of
                     Moving Expense Reimbursements summary has been enclosed
                     for your assistance. In the event that you voluntarily
                     terminate your employment with CYMER within one year of
                     your date of hire, you will be required to repay the
                     prorated amount of your relocation benefit. In addition
                     to your relocation bonus, the following relocation
                     benefits will be paid by Cymer in order to assist in
                     your move to San Diego:

                     -  One (1) house-hunting trip for you and your family
                        from Singapore to San Diego for up to seven (7) days.
                        The Company will pay for round-trip coach air-fare,
                        hotel accommodations, and a rental car. Please contact
                        Tammy Tistle at (858) 385-6587 for assistance in
                        making these reservations.

                     -  Temporary housing in a corporate apartment or similar
                        accommodations, of Cymer's choice, for a period no
                        longer than ninety (90) days.

                     -  Actual costs of packing, transportation, unpacking,
                        insurance, and storage for up to 90 days, of your
                        normal household goods and personal effects, not to
                        exceed 18,000 pounds total, from Singapore to San
                        Diego, and/or from Boise, Idaho or similar location.
                        The bulk of this shipment will be made by surface
                        transportation. For air shipment you will be
                        permitted a limit of one "LDN" 94.5 cubic foot
                        container for yourself and one "D" 63.5 cubic foot
                        container each for your wife and children.

                     -  Items not covered under this offer with regard to
                        shipping are boats, planes, ski mobiles and other
                        recreational vehicles, aquariums, articles of
                        extraordinary value (jewelry, furs, precious stones,
                        stamp or coin collections, wills, stocks, etc.),
                        firearms, ammunition, combustibles, playground
                        equipment or items of a similar nature.

                     -  The Company will reimburse you up to $300 for
                        shipment of household pets from Singapore to San
                        Diego. Shipping/importation arrangements and
                        boarding/quarantine costs will be your responsibility.

                     -  Any duty or customs fees imposed on normal household
                        goods, including those acquired by you in Singapore,
                        will be reimbursed by the Company. Customs duties
                        assessed on expensive furs, clothing, trademark items
                        and non-approved high value items will be your
                        responsibility.

                     -  One-way coach air travel for you and your family from
                        Singapore to San Diego, California when you begin
                        work at Cymer.

                     Ms. Kirsten Gilbert, 858-385-6512, will help you
                     coordinate your relocation to San Diego, including
                     coordinating with the moving company, travel, and
                     temporary accommodations.

OTHER:               You will be eligible for coverage under the Company's
                     Group Health Plans on the first day of your employment.


                                           Page 2 of 3
<PAGE>


                                                             Wallace E. Breitman
                                             Sr. Vice President, Human Resources
                                           Telephone:               858-385-6521
                                                 Fax:               858-385-6061
                                              E-mail:        wbreitman@cymer.com



                     You will be eligible to enroll in the Company's 401(k)
                     Retirement Plan on the first of the month following
                     completion of 30 days of service.

                     As a member of senior management, you will not accrue
                     either vacation or sick leave. You may take vacation
                     time and sick leave as needed and appropriate, based on
                     the requirements of your job and the approval of your
                     manager.

                     We have enclosed details of our benefits package for
                     your review.

Cymer employees are hired and work as employees-at-will, and we expect you to
comply with our standard conditions of employment such as entering into a
proprietary rights and confidentiality agreement, and providing the necessary
proof of citizenship or other status that enables the Company to legally
employ you. For the safety of our company and the security of our
technologies, all prospective employees are subject to a background check,
which may or may not be completed before you start work at Cymer. Employment,
or continued employment, with Cymer is contingent on satisfactory results of
this investigation.

I hope you will decide to join the Cymer team, as our success is derived from
the people who work here. You may accept this offer by signing below,
indicating your anticipated start date, and returning one copy of this letter
to me in the enclosed envelope. We will expect a reply from you no later than
May 12, 2000, after which we will consider this offer closed. Please retain
the extra original of this letter for your personal records.

We ask that your start date be on a Monday; this will allow us to participate
in the regular Employee Orientation Program and begin your new-hire
paperwork. Please report to our administration building (CS-1) at 16750 Via
Del Campo Court at 8:00 am and bring this entire packet of information (with
all necessary forms completed) with you. Directions to this building have
been enclosed for your use. Should you have any questions, please contact me
at 858-385-6521.

Sincerely,


Wallace E. Breitman
Sr. Vice President, Human Resources

I accept Cymer's offer of employment:

/s/ BRIAN C. KLENE                         May 8, 2000
---------------------------             ------------------------
    Brian C. Klene                      Date Signed
Signature


As soon as possible
---------------------------
Expected Start Date


June 12, 2000
---------------------------
Employment Start Date



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