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                                                                     Exhibit 4.1

                       CABOT MICROELECTRONICS CORPORATION
                AMENDED AND RESTATED 2000 EQUITY INCENTIVE PLAN

1. PURPOSE

     The purpose of this amended and restated 2000 Equity Incentive Plan (the
"Plan") is to advance the interests of Cabot Microelectronics Corporation (the
"Company") and its stockholders by enhancing the Company's ability to (a)
attract and retain employees, directors, consultants and advisors who are in a
position to make significant contributions to the success of the Company and its
subsidiaries; (b) reward these individuals for these contributions; (c)
encourage these individuals to take into account the long-term interests of the
Company and its stockholders; and (d) reward individuals who have contributed to
the Company's success (including the success of the Company's initial public
offering), in the case of each of (a) through (d), through ownership of shares
of the Company's common stock, par value $.001 per share ("Stock").

2. ADMINISTRATION

     (a) Prior to the "IPO Effective Date" (as defined in the Master Separation
Agreement, dated March 28, 2000, to which the Company is a party (the "Master
Separation Agreement")), the Plan shall be administered by the Board of
Directors of Cabot Corporation and the Board of Directors of the Company, or
either of them, and, from and after the IPO Effective Date, the Plan shall be
administered by the Compensation Committee of the Board of Directors (the
"Board") of the Company (the entity that administers the Plan, the "Committee").
The Committee shall hold meetings at such times as may be necessary for the
proper administration of the Plan. The Committee shall keep minutes of its
meetings. If the Committee consists of more than one member, a quorum shall
consist of not fewer than two members of the Committee and a majority of a
quorum may authorize any action. Any decision or determination reduced to
writing and signed by a majority of all of the members of the Committee shall be
as fully effective as if made by a majority vote at a meeting duly called and
held. The Committee shall consist of at least one director of the Company and
may consist of the entire Board; provided, however, that, from and after the IPO
Effective Date, (i) if the Committee consists of less than the entire Board,
then, with respect to any Committee action relating to an Employee who is
subject to Section 16 of the Securities Exchange Act of 1934, as amended (the
"1934 Act"), the Committee shall consist of at least two directors of the
Company, each of whom shall be a "Non-Employee Director" as defined in Rule
16b-3(b)(3) promulgated thereunder, and (ii) to the extent necessary for any
Award intended to qualify as "qualified performance-based compensation" under
Section 162(m) of the Internal Revenue Code of 1986, as amended (the "Code"), to
so qualify, each member of the Committee shall be an "outside director" (as
defined in Section 162(m) and the regulations promulgated thereunder). For
purposes of the preceding sentence, if one or more members of the Committee is
neither a Non-Employee Director nor an outside director and is recused or
abstains from voting with respect to an action taken by the Committee, then the
Committee, with respect to that action, shall be deemed to consist only of the
members of the Committee who are not so recused and who have not abstained from
voting. Subject to applicable law, the Committee may delegate its authority
under the Plan to any other person or persons.

     (b) No member of the Committee shall be liable for any action, failure to
act, determination or interpretation made in good faith with respect to this
Plan or any transaction hereunder. The Company hereby agrees to indemnify each
member of the Committee for all costs and expenses and, to the fullest extent
permitted by applicable law, any liability incurred in connection with defending
against, responding to, negotiating for the settlement of or otherwise dealing
with any claim, cause of action or dispute of any kind arising in connection
with any actions in administering this Plan or in authorizing or denying
authorization to any transaction hereunder.

     (c) Subject to the express terms and conditions set forth herein, the
Committee shall have the power from time to time:

        (i) to determine the Employees to whom Awards shall be granted under the
Plan and the number of shares of Stock subject to such Awards; to prescribe the
terms and conditions (which need not be identical) of
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each such Award; and to make any amendment or modification to any Award
Agreement consistent with the terms of the Plan;

        (ii) to construe and interpret the Plan and the Awards granted
hereunder; to establish, amend and revoke rules and regulations for the
administration of the Plan, including, but not limited to, correcting any defect
or supplying any omission, or reconciling any inconsistency in the Plan or in
any Award Agreement, in the manner and to the extent it shall deem necessary or
advisable; to interpret the Plan and applicable Award Agreements so that the
Plan and its operation complies with Section 16 of the 1934 Act, Sections 162(m)
and 422 of the Code and other applicable law; and otherwise to give full effect
to the Plan;

        (iii) to exercise its discretion with respect to the powers and rights
granted to it as set forth in the Plan; and

        (iv) generally, to exercise such powers and to perform such acts as are
deemed by it necessary or advisable to promote the best interests of the Company
with respect to the Plan.

     All decisions and determinations of the Committee in the exercise of the
foregoing powers shall be final, binding and conclusive upon the Company, its
affiliates, all Employees and all other persons claiming any interest herein.

3. EFFECTIVE DATE AND TERM OF PLAN

     The Plan will become effective on the date on which it is adopted by the
Board, subject to the approval of Cabot Corporation as the sole stockholder of
the Company. No Award may be granted under the Plan after the tenth anniversary
of the date on which this Plan was adopted by the Board, but Awards previously
granted may extend beyond that date.

4. SHARES SUBJECT TO THE PLAN

     Subject to adjustment as provided in Section 8.6, and subject to the next
following sentence and Section 6.3(a), the maximum number of shares of Stock
that may be delivered under the Plan will be (a) 6,500,000 shares of Stock; plus
(b) any shares of Stock subject to Awards granted under the Plan and thereafter
forfeited; plus (c) without duplication for shares counted under the immediately
preceding clause, a number of shares of Stock equal to the number of shares
repurchased by the Company in the open market or otherwise and having an
aggregate repurchase price no greater than the amount of cash proceeds received
by the Company from the sale of shares of Stock under the Plan; plus (d) any
shares of Stock surrendered to the Company in payment of the exercise price of
Options issued under the Plan. However, in no event shall the Company issue ISOs
(as defined in Section 6.2(a)) under the Plan covering more than 1,750,000
shares of Stock.

     Stock delivered under the Plan may be either from authorized but unissued
Stock, from treasury shares or from shares of Stock purchased in open-market
transactions and private sales.

5. ELIGIBILITY AND PARTICIPATION

     Those eligible to receive Awards under the Plan will be employees,
directors, consultants and advisors of the Company or any of its affiliates
("Employees") who, in the opinion of the Committee, are in a position to make a
significant contribution to the success of the Company and its subsidiaries. An
"affiliate" for purposes of the Plan is an entity that controls, is controlled
by or is under common control with, the Company. A "subsidiary" for purposes of
the Plan is an entity in which the Company owns, directly or indirectly, equity
interests possessing a majority of the total combined voting power of all
classes of equity. The Committee will from time to time select the Employees who
are to be granted Awards ("Participants"), but no Participant shall receive
Awards under the Plan covering more than 300,000 shares of Stock (subject to
adjustment as provided in Section 8.6) in any calendar year.



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6. TYPES OF AWARDS

  6.1. RESTRICTED STOCK.

     (a) Nature of Restricted Stock Award. An Award of Restricted Stock entitles
the recipient to acquire, at such time or times as the Committee may determine,
shares of Stock subject to the restrictions described in paragraph (d) below
("Restricted Stock"). The Committee may require, as a condition to an Award of
Restricted Stock, that an Employee deliver to the Company a purchase price in
any amount set by the Committee for such Restricted Stock. In no event shall the
Company issue more than 875,000 shares of Restricted Stock under the Plan.

     (b) Payment for Restricted Stock. In the discretion of the Committee, an
Award Agreement evidencing an Award of Restricted Stock may permit the
Participant to pay some or all of the purchase price thereof, or to meet any
Withholding Requirements to be met by the Participant in connection therewith,
in the form of a note from the Participant on such terms as the Committee shall
determine. Such terms may include forgiveness of all or a portion of any such
note upon such conditions as the Committee may specify.

     (c) Rights as a Stockholder. A Participant who receives an Award of
Restricted Stock will have all the rights of a stockholder with respect to the
Stock, including voting and dividend rights, subject to the restrictions
described in paragraph (d) below and any other conditions imposed by the
Committee in the Award Agreement at the time of grant.

     (d) Restrictions. The restrictions on each grant of Restricted Stock will
lapse at such time or times, and on such terms and conditions (including
obtaining pre-established performance goals), as the Committee may specify.
Except as otherwise specifically provided by the Plan or by the Committee in any
particular case, until these restrictions lapse, Restricted Stock may not be
sold, assigned, transferred, pledged or otherwise encumbered or disposed of,
except that Restricted Stock may be pledged as security for the purchase price
thereof, or for loans used to fund any or all of the purchase price thereof or
Withholding Requirements met in connection with the purchase thereof. If the
Participant ceases to be an Employee before such restrictions have lapsed, the
Company shall have the right to repurchase the Restricted Stock for the amount
of any consideration (excluding services) it received for the Restricted Stock
plus, if the Committee shall so determine, an amount equal to the Withholding
Requirements met by the Participant in connection with the sale of the Stock, or
for such other consideration as the Committee shall determine, including for no
consideration if no consideration other than services was paid for such
Restricted Stock. The Committee shall not accelerate the time at which the
restrictions on all or any part of a grant of Restricted Stock will lapse,
except as the Committee may determine to be appropriate in connection with a
Participant's termination as an Employee.

     (e) Section 83(b) Election. Under Section 83 of the Code, the difference
between the purchase price paid for the Stock and its Fair Market Value (as
defined in Section 6.2(b)) on the date any restrictions applicable to such
shares lapse will be reportable as ordinary income at that time. A Participant
may elect to be taxed at the time the shares of Stock are acquired hereunder to
the extent the Fair Market Value of the Stock differs from the purchase price
rather than when and as such Stock ceases to be subject to restrictions, by
filing an election under Section 83(b) of the Code with the I.R.S. within thirty
(30) days after the grant date. If the Fair Market Value of the Stock at the
grant date equals the purchase price paid (and thus no tax is payable), the
election must be made to avoid adverse tax consequences in the future. The form
for making this election is available from the Company. The failure to make this
filing within the thirty (30) day period will result in the recognition of
ordinary income by the Participant (in the event the Fair Market Value of the
Stock increases after the grant date) as the restrictions lapse. IT IS THE
PARTICIPANT'S SOLE RESPONSIBILITY, AND NOT THE COMPANY'S, TO FILE A TIMELY
ELECTION UNDER SECTION 83(b). A PARTICIPANT MUST RELY SOLELY ON THE
PARTICIPANT'S OWN ADVISORS WITH RESPECT TO THE DECISION AS TO WHETHER OR NOT TO
FILE AN 83(b) ELECTION.


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  6.2. OPTIONS.

     (a) Nature of Options. An Option is an Award entitling the recipient on
exercise thereof to purchase shares of Stock at a specified exercise price. Both
incentive stock options (as defined in Section 422 of the Code) ("ISOs") and
Options that are not ISOs may be granted under the Plan.

     (b) Exercise Price. The exercise price of an Option shall be determined by
the Committee and set forth in an applicable Award Agreement; provided, however,
that the exercise price of an ISO shall not be less than the Fair Market Value
of a share of the Stock on the date the ISO is granted (110% of the Fair Market
Value of a share of Stock on the date of grant in the case of an ISO granted to
an Employee who owns (within the meaning of Section 422(b)(6) of the Code) stock
possessing more than ten percent of the total combined voting power of all
classes of stock of the Company, or of a parent or a subsidiary (such person, a
"Ten Percent Shareholder")). For purposes of this Plan, "Fair Market Value" on
any date means the closing sales price of the Stock on such date on the
principal national securities exchange on which the Stock is listed or admitted
to trading, or, if the Stock is not so listed or admitted to trading, the
average of the per share closing bid price and per share closing asked price on
such date as quoted on the National Association of Securities Dealers Automated
Quotation System or such other market in which such prices are regularly quoted,
or, if there have been no published bid or asked quotations with respect to
shares on such date, the Fair Market Value shall be the value established by the
Board in good faith and, in the case of an ISO, in accordance with Section 422
of the Code; provided that the "Fair Market Value" of any Option granted prior
to the IPO Effective Date shall be the initial public offering price of the
Stock.

     (c) Duration of Options. The latest date on which an Option may be
exercised will be the tenth anniversary of the date the Option was granted (five
years in the case of an ISO granted to a Ten Percent Shareholder), or such
earlier date as may have been specified by the Committee in the Award Agreement
at the time the Option was granted.

     (d) Exercise of Options. An Option will become exercisable at such time or
times, and on such terms and conditions (including obtaining pre-established
performance goals), as the Committee may specify in the Award Agreement for such
Option. The Committee may at any time accelerate the time at which all or any
part of the Option may be exercised.

     Subject to the next following sentence, any exercise of an Option must be
in writing, signed by the proper person and delivered or mailed to the Company,
accompanied by (1) any documents required by the Committee and (2) payment in
full for the number of shares for which the Option is exercised. The exercise
price for any Stock purchased pursuant to the exercise of an Option may, if
permitted under the Award Agreement applicable to the Option, be paid in the
following forms: (a) cash; (b) the transfer, either actually or by attestation,
to the Company of shares of Stock that have been held by the Participant for at
least six months (or such lesser period as may be permitted by the Committee)
prior to the exercise of the Option, such transfer to be upon such terms and
conditions as determined by the Committee; or (c) a combination thereof. In
addition, Options may be exercised through a registered broker-dealer pursuant
to such cashless exercise procedures which are, from time to time, deemed
acceptable by the Committee. Any shares of Stock transferred to the Company as
payment of the exercise price under an Option shall be valued at their Fair
Market Value on the day of exercise of such Option. If requested by the
Committee, the Participant shall deliver the Award Agreement to the Secretary of
the Company who shall endorse thereon a notation of such exercise and return
such Award Agreement to the Participant. No fractional shares of Stock (or cash
in lieu thereof) shall be issued upon exercise of an Option, and the number of
shares of Stock that may be purchased upon exercise shall be rounded to the
nearest number of whole shares.

     (e) Exercise Limit. To the extent that the aggregate Fair Market Value
(determined as of the date of the grant) of shares of Stock with respect to
which ISOs granted under the Plan and "incentive stock options" (within the
meaning of Section 422 of the Code) granted under all other plans of the Company
or its subsidiaries (in either case determined without regard to this Section
6.2(e)) are exercisable by a Participant for the first time during any calendar
year exceeds $100,000, such ISOs shall be treated as Options which are not ISOs.
In applying the limitation in the preceding sentence in the case of multiple
Options, Options which


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are intended to be ISOs shall be treated as Options which are not ISOs according
to the order in which they were granted, such that the most recently granted
Options are first treated as Options which are not ISOs.

  6.3. SUBSTITUTE AWARDS.

     (a) The Committee may grant Awards to Employees who hold outstanding awards
of stock options and restricted stock granted under the equity incentive awards
of Cabot Corporation (the "Cabot Awards"), in cancellation of the Cabot Awards.
It is intended that such Awards shall preserve for the Participants the economic
values of the equity incentives for which such Awards are substituted and shall
be subject to substantially similar terms of conditions as the Cabot Awards (but
any such Awards shall reflect the performance of the Stock and not the
performance of Cabot common stock), in each case as determined by the Committee
in its sole discretion. Any cancellation of a Cabot Award pursuant to this
Section 6.3(a) shall be subject to the terms of such Cabot Award.

     (b) In connection with any acquisition by the Company or any of its
subsidiaries, the Committee may grant Awards to persons who became Employees in
connection with such acquisition in substitution for equity incentives held by
them in the seller or acquired entity. In such case the Committee may set the
prices and other terms of the substitute Awards at such amounts and in such
manner as it, in its sole discretion, deems appropriate to preserve for the
Participants the economic values of the equity incentives for which such Awards
are substitutes (as determined by the Committee in its sole discretion) or
otherwise to provide such incentives as the Committee may determine are
appropriate.

     (c) Unless required by applicable law, any substitute Awards granted
pursuant to Section 6.3 shall not count toward the share limitations set forth
in Section 4.

7. EVENTS AFFECTING OUTSTANDING AWARDS

  7.1. TERMINATION OF EMPLOYMENT.

     Unless otherwise set forth in an Award Agreement, an Award shall
immediately terminate on the date a Participant ceases to be an Employee, and
(i) any Options held by a Participant shall not be exercisable and all rights of
the Participant with respect thereto shall immediately terminate and (ii) any
shares of Restricted Stock with respect to which the restrictions have not
lapsed shall be immediately forfeited and must be transferred to the Company in
accordance with Section 6.1.

  7.2 TERMINATION OF AWARD.

     The Company may terminate, cancel, rescind or recover an Award immediately
under certain circumstances, including, but not limited to a Participant's:

     (a) actions constituting "Cause", which shall have the meaning provided
under an employment agreement between a Participant and the Company, or if there
is no such meaning provided under such agreement or no such agreement, shall
include, but not be limited to, the: (i) conviction of or entering a guilty plea
with respect to a crime, whether or not connected with the Company; (ii)
commission of any act of fraud with respect to the Company; (iii) theft,
embezzlement or misappropriation of any property of the Company; (iv) excessive
absenteeism (other than as resulting from Disability); (v) failure to observe or
comply with any Company work rules, policies, procedures, guidelines or
standards of conduct which the Company has adopted for the regulation of the
general conduct of its employees, as generally known to the employees of the
Company or evidenced by the terms of any employee handbook, written memorandums
or written policy statements; (vi) continued willful refusal to carry out and
perform the material duties and responsibilities of a Participant's position,
excluding nonperformance resulting from Disability; or (vii) any other conduct
or act determined to be injurious, detrimental or prejudicial to any interest of
the Company, (in each case as determined in good faith by the Company.);

     (b) rendering of services for a competitor prior to, or within six (6)
months after, the exercise of any Option or the termination of Participant's
employment with the Company;


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     (c) unauthorized disclosure of any confidential/proprietary information of
the Company to any third party;

     (d) failure to comply with the Company's policies regarding the
identification, disclosure and protection of intellectual property; or

     (e) violation of the Proprietary Rights Agreement/Cabot Microelectronics
Corporation Employee Confidentiality, Intellectual Property and Non-Competition
Agreement for Employees signed by the Participant.

     The existence of any such circumstances shall be determined in good faith
by the Company.

     In the event of any termination, cancellation, recision or revocation, the
Participant shall return to the Company any Stock received pursuant to an Award,
or pay to the Company the amount of any gain realized on the sale of any such
Stock, in such manner and on such terms and conditions as may be required, and
the Company shall be entitled to set-off against the amount of any such gain any
amount owed to the Participant by the Company. To the extent applicable, the
Company will refund to the Participant any amount paid for such Stock, including
Withholding Requirements.

  7.3 CHANGE IN CONTROL.

     The Committee shall have the discretion to provide in applicable Award
Agreements that, in the event of a "Change in Control" (as defined in Appendix
A) of the Company, the following provisions will apply:

          (a) Each outstanding Option (or such lesser portion of each Option as
     is set forth in an applicable Award Agreement) will immediately become
     exercisable in full.

          (b) Each outstanding share of Restricted Stock (or such lesser number
     of shares as is set forth in an applicable Award Agreement) will
     immediately become free of the restrictions.

          (c) In the event of a Change in Control which is a merger or
     consolidation in which the Company is not the surviving corporation or
     which results in the acquisition of substantially all the Company's
     outstanding Stock by a single person or entity or by a group of persons or
     entities acting in concert, or in the event of a sale or transfer of all or
     substantially all of the Company's assets (a "Covered Transaction"), for
     the termination of all outstanding Options as of the effective date of the
     Covered Transaction, subject to the following: If the Covered Transaction
     follows a Change in Control or would give rise to a Change in Control, no
     Option will be so terminated (without the consent of the Participant) prior
     to the expiration of 20 days following the later of (i) the date on which
     the Award became fully exercisable and (ii) the date on which the
     Participant received written notice of the Covered Transaction.

8. GENERAL PROVISIONS

  8.1. DOCUMENTATION OF AWARDS.

     Awards will be evidenced by written instruments prescribed by the Committee
from time to time (each such instrument, an "Award Agreement"). Award Agreements
may be in the form of agreements, to be executed by both the Participant and the
Company, or certificates, letters or similar instruments, acceptance of which
will evidence agreement to the terms thereof and hereof.

  8.2. RIGHTS AS A STOCKHOLDER; DIVIDEND EQUIVALENTS.

     Except as specifically provided by the Plan, the receipt of an Award will
not give a Participant rights as a stockholder, and the Participant will obtain
such rights, subject to any limitations imposed by the Plan or the Award
Agreement, upon actual receipt of Stock. However, the Committee may, on such
conditions as it deems appropriate, provide in an Award Agreement that a
Participant will receive a benefit in lieu of cash dividends that would have
been payable on any or all Stock subject to the Participant's Award had such
Stock been outstanding. Without limitation, the Committee may provide for
payment to the Participant of amounts


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representing such dividends, either currently or in the future, or for the
investment of such amounts on behalf of the Participant.

8.3 CONDITIONS ON DELIVERY OF STOCK.

     The Company will not be obligated to deliver any shares of Stock pursuant
to the Plan or to remove any restriction from shares of Stock previously
delivered under the Plan (a) until all conditions of the Award have been
satisfied or removed, (b) until, in the opinion of the Company's counsel, all
applicable federal and state laws and regulations have been complied with, (c)
if the outstanding Stock is at the time listed on any stock exchange, until the
shares to be delivered have been listed or authorized to be listed on such
exchange upon official notice of notice of issuance and (d) until all other
legal matters in connection with the issuance and delivery of such shares have
been approved by the Company's counsel. If the sale of Stock has not been
registered under the Securities Act of 1933, as amended, the Company may
require, as a condition to exercise of the Award, such representations or
agreements as counsel for the Company may consider appropriate to avoid
violation of such Act and may require that the certificates evidencing such
Stock bear an appropriate legend restricting transfer.

  8.4. TAX WITHHOLDING.

     The Company will withhold from any payment made pursuant to an Award an
amount as may be necessary sufficient to satisfy all minimum federal, state and
local withholding tax requirements (the "Withholding Requirements").

     The Committee will have the right to require that the Participant or other
appropriate person remit to the Company an amount sufficient to satisfy the
Withholding Requirements, or make other arrangements satisfactory to the
Committee with regard to such requirements, prior to the delivery of any Stock.
If and to the extent that any such withholding is required, the Committee may
permit the Participant or such other person to elect at such time and in such
manner as the Committee provides to have the Company hold back from the shares
to be delivered, or to deliver to the Company, Stock having a value calculated
to satisfy the Withholding Requirements.

     If at the time an ISO is exercised the Committee determines that the
Company could be liable for Withholding Requirements with respect to a
disposition of the Stock received upon exercise, the Committee may require as a
condition of exercise that the person exercising the ISO agree (a) to inform the
Company promptly of any disposition of Stock received upon exercise of the ISO,
and (b) to give such security as the Committee deems adequate to meet the
potential liability of the Company for the Withholding Requirements and to
augment such security from time to time in any amount reasonably deemed
necessary by the Committee to preserve the adequacy of such security.

  8.5. NONTRANSFERABILITY OF AWARDS.

     No Option shall be transferable by a Participant otherwise than by will or
by the laws of descent and distribution or, in the case of an Option other than
an ISO, pursuant to a domestic relations order (within the meaning of Rule
16a-12 promulgated under the Exchange Act), and an Option shall be exercisable
during the lifetime of such Participant only by such Participant or such
Participant's executor or administrator or by the person or persons to whom the
Option is transferred by will or the applicable laws of descent and distribution
(such person, the Participant's "Legal Representative"). Notwithstanding the
foregoing sentence, the Committee may set forth in an Award Agreement evidencing
an Option (other than an ISO), that the Option may be transferred to members of
the Participant's immediate family, to trusts solely for the benefit of such
immediate family members and to partnerships in which such family members and/or
trusts are the only partners, and for purposes of this Plan, such a transferee
of an Option shall be deemed to be the Participant. For this purpose, "immediate
family" shall refer only to the Participant's spouse, parents, children,
stepchildren and grandchildren and the spouses of such parents, children,
stepchildren and grandchildren. The terms of an Option shall be final, binding
and conclusive upon the beneficiaries, executors, administrators, heirs and
successors of the Participant.


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  8.6. ADJUSTMENTS IN THE EVENT OF CERTAIN TRANSACTIONS.

     In the event that the outstanding shares of Stock are changed into or
exchanged for a different number or kind of shares of stock, other securities or
other property of the Company, an affiliate or another legal entity, whether
through merger, consolidation, reorganization, recapitalization, stock dividend,
stock split-up or other substitution of securities of the Company, an affiliate
or another entity, the Committee shall make appropriate adjustments to the
maximum number and kind of shares of stock or other equity interest as to which
Awards may be granted under the Plan and the number and kind of shares of stock
or other equity interest with respect to which Awards have been granted under
the Plan, the exercise prices for such shares or other equity interest subject
to Options and any other economic terms of Awards granted under the Plan; and
provided, that, in the event of a merger of the Company with or into another
entity, any adjustment provided for in the applicable agreement and plan of
merger (or similar document) shall be conclusively deemed to be appropriate for
purposes of this Section 8.6. The Committee's adjustment shall be final and
binding for all purposes of the Plan and each Award Agreement entered into under
the Plan. Unless the Committee otherwise determines, no adjustment provided for
in this Section 8.6 shall require the Company to issue a fractional share, and,
in such event, with respect to each Award Agreement the total adjustment as to
the number of shares for which Awards have been granted shall be effected by
rounding down to the nearest whole number of shares.

  8.7. EMPLOYMENT RIGHTS.

     Neither the adoption of the Plan nor the grant of Awards will confer upon
any person any right to continued employment with the Company or any subsidiary
or affect in any way the right of the Company or affiliate to terminate an
employment relationship at any time.

  8.8. PAYMENT FOR STOCK; LOANS.

     Stock awarded under this Plan as Restricted Stock or received upon exercise
of an Option may be paid for with such legal consideration as the Committee may
determine. If and to the extent authorized by the Committee, the Company may
permit Participants to pay for Stock with promissory notes, and may make loans
to Participants of all or a portion of any Withholding Requirements to be met in
connection with the grant, exercise or vesting of any Award. Any such extensions
of credit may be secured by Stock or other collateral, or may be made on an
unsecured basis, as the Committee may determine.

9. DISCONTINUANCE, CANCELLATION, AMENDMENT AND TERMINATION

     The Committee may at any time discontinue granting Awards under the Plan.
The Board may at any time or times amend the Plan and, with the consent of the
holder thereof, any outstanding Award. The Committee may at any time terminate
the Plan as to any further grants of Awards, provided that (except to the extent
expressly required or permitted by the Plan) no such amendment will, without the
approval of the stockholders of the Company, (a) increase the maximum number of
shares available under the Plan, (b) extend the time within which Awards may be
granted, or (c) amend the provisions of this Section 9, and no amendment or
termination of the Plan may adversely affect the rights of any Participant
(without his or her consent) under any Award previously granted.

                                          CABOT MICROELECTRONICS
                                          CORPORATION

                                          By:  /s/ Matthew Neville
                                             ---------------------------------
                                                   Matthew Neville


<PAGE>

                    APPENDIX A TO AMENDED AND RESTATED 2000
                             EQUITY INCENTIVE PLAN

     A "Change in Control" shall be deemed to have occurred if, following the
"Distribution" (as defined in the Master Separation Agreement):

     (a) any "person" as such term is used in Sections 13(d) and 14(d) of the
1934 Act (other than (i) the Company, (ii) any subsidiary of the Company, (iii)
any trustee or other fiduciary holding securities under an employee benefit plan
of the Company or of any subsidiary of the Company, or (iv) any company owned,
directly or indirectly, by the stockholders of the Company in substantially the
same proportions as their ownership of stock of the Company), is or becomes the
"beneficial owner" (as defined in Section 13(d) of the 1934 Act), together with
all Affiliates and Associates (as such terms are used in Rule 12b-2 of the
General Rules and Regulations under the 1934 Act) of such person, directly or
indirectly, of securities of the Company representing thirty percent (30%) or
more of the combined voting power of the Company's then outstanding securities;
or

     (b) the stockholders of the Company approve a merger or consolidation of
the Company with any other company, other than (i) a merger or consolidation
which would result in the voting securities of the Company outstanding
immediately prior thereto continuing to represent (either by remaining
outstanding or by being converted into voting securities of the surviving
entity), in combination with the ownership of any trustee or other fiduciary
holding securities under an employee benefit plan of the Company or any
subsidiary of the Company, at least sixty percent (60%) of the combined voting
power of the voting securities of the Company or such surviving entity
outstanding immediately after such merger or consolidation or (ii) a merger or
consolidation effected to implement a recapitalization of the Company (or
similar transaction) after which no "person" (with the method of determining
"beneficial ownership" used in clause (a) of this definition) owns more than
thirty percent (30%) of the combined voting power of the securities of the
Company or the surviving entity of such merger or consolidation; or

     (c) during any period of two consecutive years (not including any period
prior to the execution of the Plan), individuals who at the beginning of such
period constitute the Board, and any new director (other than a director
designated by a person who has conducted or threatened a proxy contest, or has
entered into an agreement with the Company to effect a transaction described in
clause (a), (b) or (d) of this definition) whose election by the Board or
nomination for election by the Company's stockholders was approved by a vote of
at least two-thirds (2/3) of the directors then still in office who either were
directors at the beginning of the period or whose election or nomination for
election was previously so approved cease for any reason to constitute at least
a majority thereof; or

     (d) the stockholders of the Company approve a plan of complete liquidation
of the Company or an agreement for the sale or disposition by the Company of all
or substantially all of the Company's assets.