Exhibit 4.5


                               STATS ChipPAC LTD.
                    SUBSTITUTE SHARE PURCHASE AND OPTION PLAN

         1. Purpose of Plan. Pursuant to that certain Agreement and Plan of
Merger and Reorganization, dated as of February 10, 2004 (the "Merger
Agreement"), among ST Assembly Test Services Ltd., a Singapore public company
limited by shares ("STATS"), Camelot Merger, Inc. and ChipPAC, Inc., a Delaware
corporation ("ChipPAC"), ChipPAC will become a wholly owned subsidiary of STATS.
Under the terms of the Merger Agreement, STATS agreed to grant Substitute
Options (as hereinafter defined) in substitution for the Options (as hereinafter
defined) that were outstanding and unexercised immediately prior to the
Effective Time (as defined in the Merger Agreement) on substantially the same
terms in all material respects as were applicable to the Options that were
substituted with the Substitute Options. The Merger Agreement also provides for
the change of the name of the combined company, effective as of the Effective
Time, to "STATS ChipPAC Ltd." This STATS ChipPAC Ltd. Substitute Share Purchase
and Option Plan (the "Plan") of STATS ChipPAC Ltd., a Singapore public company
limited by shares (the "Company"), which is designed to provide for the grant of
Substitute Options to holders of Options in accordance with the terms of the
Merger Agreement, shall not become effective until the Effective Time.

         2. Definitions. The capitalized terms used in the Plan have the
meanings set forth below:

         "ADS" means an American Depositary Share issued pursuant to the deposit
agreement, dated as of February 8, 2001, as may be amended from time to time, by
and among STATS, Citibank, N.A., as depositary, and the holders from time to
time of ADSs (evidenced by American Depositary Receipts). Each ADS represents
the right to receive ten Shares.

         "Board" means the Company's board of directors.

         "ChipPAC" has the meaning ascribed to it in Section 1 hereof.

         "ChipPAC Share" means a share of Class A Common.

         "Class A Common" means the Class A Common Stock, par value $.01 per
share, of ChipPAC.

         "Code" means the Unites States Internal Revenue Code of 1986, as it may
be amended from time to time, and the rules and regulations promulgated
thereunder.

         "Committee" means the committee of the Board that may be designated by
the Board to administer the Plan. The Committee shall be composed of two or more
members as appointed to serve from time to time by the Board. In the absence of
the appointment of any such Committee, any action permitted or required to be
taken hereunder by the Committee shall be deemed to refer to the Board.

         "Company" has the meaning ascribed to it in Section 1 hereof.

         "Effective Time" has the meaning ascribed to it in Section 1 hereof.





         "ESOP" means the STATS ChipPAC Ltd. Share Option Plan, as may be
amended from time to time.

         "Exchange Ratio" means the numeral 8.7.

         "Fair Market Value" means, as of any date, the value of Shares
determined as follows:

         (i)     If the Shares are listed on any established stock exchange or a
national market system, including, without limitation, The Nasdaq National
Market or The Nasdaq SmallCap Market of The Nasdaq Stock Market, the Fair Market
Value shall be the closing sales price for the Shares (or the closing bid, if no
sales were reported) as quoted on such exchange or system for the last market
trading day prior to the time of determination, as reported in The Wall Street
Journal or such other source as the Committee deems reliable;

         (ii)    If the Shares are regularly quoted by a recognized securities
dealer but selling prices are not reported, the Fair Market Value shall be the
mean between the high bid and low asked prices for the Shares on the last market
trading day prior to the time of determination, as reported in The Wall Street
Journal or such other source as the Committee deems reliable; or

         (iii)   In the absence of an established market for the Shares, the
Fair Market Value shall be determined in good faith by the Committee.

         "Former Plan" means the ChipPAC, Inc. 1999 Stock Purchase and Option
Plan.

         "Incentive Stock Option" means an Option intended to qualify as an
incentive stock option within the meaning of Section 422 of the Code, or a
Substitute Option granted in substitution for an Option that was granted as an
Incentive Stock Option, as applicable given the context.

         "Option" means an option enabling the holder thereof to purchase
ChipPAC Shares from ChipPAC granted pursuant to the terms of the Former Plan
that is outstanding and unexercised immediately prior to the Effective Time,
that has a per Share exercise price that is equal to or greater than the par
value of a Share, after giving effect to the Exchange Ratio and the applicable
currency exchange rate conversion and that is eligible to be substituted with a
Substitute Option pursuant to the provisions of the Plan. Options granted under
the Former Plan may have been granted as Incentive Stock Options or in such
other form, consistent with the Former Plan, as the plan administrator of the
Former Plan may have determined.

         "Plan" means this STATS ChipPAC Ltd. Substitute Share Purchase and
Option Plan, as amended from time to time.

         "Participant" means the holder of an outstanding Substitute Option
granted under the Plan.

         "Plan" has the meaning ascribed to the term in Section 1 hereof.


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         "Share" means an ordinary share of STATS ChipPAC Ltd., par value S$0.25
per share.

         "Subsidiary" means any corporation of which shares of stock having a
majority of the general voting power in electing the board of directors are, at
the time as of which any determination is being made, owned by the Company
either directly or through its Subsidiaries.

         "Substitute Option" means an option granted pursuant to the terms of
the Plan in substitution for an Option and representing the right to receive,
upon exercise thereof, a number of Shares equal to the product of the number of
ChipPAC Shares subject to the Option substituted with the Substitute Option,
multiplied by the Exchange Ratio (rounded down to the nearest whole Share).

         "Substitute Option Notice" means the written or electronic notice that
shall be delivered to a holder of an Option informing the holder that his or her
Option shall be substituted with a Substitute Option and providing information
regarding the number of Shares for which the Substitute Option shall be
exercisable and the exercise price applicable to the Substitute Option. The
Substitute Option Notice shall become part of the agreement evidencing the
Option and shall supersede the applicable terms contained in the notice of grant
and agreement evidencing the grant of the Option entered into with the holder of
the Option, including without limitation, the number of Shares subject, and the
exercise price applicable, to the Option, all as set forth in the Substitute
Option Notice.

         3. Grant of Substitute Options. A holder of an Option that is
outstanding and unexercised immediately prior to the Effective Time shall be
granted a Substitute Option subject to the terms and conditions set forth in
this Section 3. Anything in the Plan to the contrary notwithstanding, the holder
of a Substitute Option may elect to receive ADSs in lieu of Shares upon the
exercise of a Substitute Option, and upon such election, the holder of the
Substitute Option shall receive a number of ADSs equal to the quotient resulting
from dividing the number of Shares subject to the Option for which a Substitute
Option is exercisable, by the number 10 (rounded down to the nearest whole ADS).
The per Share exercise price of a Substitute Option shall be equal to the
quotient (rounded up to the nearest cent) resulting from dividing the per
ChipPAC Share exercise price of the Option substituted with the Substitute
Option, by the Exchange Ratio; provided, however, that the per Share exercise
price of a Substitute Option shall in no event be less than par value of a
Share. The exercise period within which a Substitute Option is exercisable shall
be the same exercise period applicable to the Option substituted with the
Substitute Option; provided, however, that (i) the exercise period applicable to
a Participant who was an employee of ChipPAC or any Subsidiary at the time of
grant of an Option and a Substitute Option shall in no event be greater than 120
months, measured from the date of grant of the Option so substituted and (ii)
that the exercise period applicable to a Participant who was not an employee of
the Company or any Subsidiary at the time of grant of a Substitute Option shall
in no event be greater than 60 months, measured from the date of grant of the
Substitute Option. The Substitute Option shall not be transferable other than by
will or under the laws of descent and distribution. The rate at which a
Substitute Option is exercisable shall be the same rate applicable to the Option
substituted with the Substitute Option. Unless a Participant's employment with
the Company or any Subsidiary is terminated for cause, as defined by applicable
law or the terms of any agreement evidencing any grant of the Option substituted
with


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the Substitute Option or a contract of employment, a Participant shall have the
right to exercise, in the event of termination of employment, to the extent that
the Participant is otherwise entitled to exercise on the date employment
terminates, for a period of (A) not less than six (6) months from the date of
termination if termination was caused by death or disability and (B) not less
than 30 days from the date of termination if termination was caused by any
reason other than death or disability. Substitute Options granted under the Plan
shall be subject to such terms and conditions and evidenced by agreements as
shall be determined from time to time by the Committee to the extent not
inconsistent with the provisions of the Plan.

         4. [INTENTIONALLY LEFT BLANK]

         5. Administration of the Plan. The Committee shall have the power and
authority to prescribe, amend and rescind rules and procedures governing the
administration of the Plan, including, but not limited to, the full power and
authority (i) to specify and approve the provisions of agreements evidencing any
grant of any Substitute Option, including, without limitation, the method of
exercise, including via written or electronic media, (ii) to interpret the terms
of the Plan, the terms of any Substitute Options granted under the Plan,
consistent with the provisions of the Plan, including, without limitation, the
terms and conditions set forth in Section 3 hereof, and the rules and procedures
established by the Committee governing any such Substitute Options and (iii) to
determine the rights of any person under the Plan, or the meaning of
requirements imposed by the terms of the Plan or any rule or procedure
established by the Committee. Each action of the Committee shall be binding on
all persons. In administering the Plan, the Committee shall provide the
Participants with such financial statements as may be required pursuant to
applicable law.

         6. Limitation on the Aggregate Number of Shares. The number of Shares
issued under the Plan (including the number of Shares with respect to which
Substitute Options may be granted under the Plan (and which may be issued upon
the exercise or payment thereof)) shall not exceed, in the aggregate, 7.2
million Shares, which is an aggregate number that is intended to be equal to or
greater than the product of the aggregate number of ChipPAC Shares subject to
all Options, multiplied by the Exchange Ratio (as such numbers are equitably
adjusted pursuant to Section 9 hereof). If any Substitute Options expire
unexercised or unpaid or are canceled, terminated or forfeited in any manner
without the issuance of Shares or payment thereunder, the Shares with respect to
which such Substitute Options were granted shall become available for issuance
pursuant to options or other awards under the ESOP. In addition, Shares that are
not made subject to Substitute Options hereunder shall become available for
issuance pursuant to options or other awards under the ESOP. Shares to be issued
upon exercise of a Substitute Option may be authorized, but unissued Shares, as
the Committee shall determine.

         7. Incentive Stock Options. All Incentive Stock Options shall comport
with all requirements set forth in Section 422 of the Code. To the extent that
the aggregate Fair Market Value of Shares with respect to which Substitute
Options that are intended to be Incentive Stock Options are exercisable for the
first time by any individual during any calendar year exceeds US$100,000
(measured as of the date the Options substituted with the Substitute Options
were granted), such options shall be treated as options that are not Incentive
Stock Options.

         8. [INTENTIONALLY LEFT BLANK]


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         9. Adjustment for Change in Capitalization of the Company. In the event
of a reorganization, recapitalization, stock split, stock dividend, combination
of shares, merger, consolidation or other change in the Shares or ADSs, the
Committee shall make appropriate changes in the number and type of shares
authorized by the Plan, the number and type of shares covered by outstanding
Substitute Options and the exercise prices thereof.

         10. Taxes. The Company shall be entitled, if necessary or desirable, to
withhold (or secure payment from the Participant in lieu of withholding) the
amount of any withholding or other tax due from the Company with respect to any
amount payable and/or Shares of ADSs issuable under the Plan, and the Company
may defer such payment or issuance unless indemnified to its satisfaction.

         11. Termination and Amendment. The Committee at any time may suspend or
terminate the Plan and make such additions or amendments as it deems advisable
under the Plan, except that the Committee shall obtain shareholder approval of
any amendment to the Plan to the extent necessary and desirable to comply with
applicable law; provided that, subject to Section 8 hereof, the Committee shall
not change any of the terms of a written agreement with respect to an Option or
Substitute Option between the Company and a Participant without the approval of
the Participant. Unless terminated earlier in accordance with this Section 11,
the Plan shall terminate on the earlier of the tenth anniversary of the date the
Plan becomes effective and the date that each Substitute Option has been
exercised.

         12. Shareholder Approval. The Plan shall be subject to approval by the
shareholders of the Company at the time that the transactions contemplated by
the Merger Agreement are subject to shareholder approval. Such shareholder
approval shall be obtained in the manner and to the degree required under
applicable laws. The Plan shall not become effective and no Substitute Option
shall be granted under the Plan in the event that the Plan is not approved by
the shareholders of the Company, and in no event prior to the Effective Time.

         13. Governing Law. The validity, construction, interpretation,
administration and effect of the Plan shall be determined in accordance with the
laws of the Republic of Singapore.

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