<PAGE>   1
                                                                    EXHIBIT 4.6


                            DATED 14TH DECEMBER, 2000





                       CHARTERED SILICON PARTNERS PTE LTD
                                   AS BORROWER


                    CHARTERED SEMICONDUCTOR MANUFACTURING LTD
                             EDB INVESTMENTS PTE LTD
                        AGILENT TECHNOLOGIES EUROPE B.V.
                                 AS SHAREHOLDERS


                                     - AND -


                      ABN AMRO BANK N.V., SINGAPORE BRANCH
                                    AS AGENT






              ---------------------------------------------------

                         THIRD SUPPLEMENTAL SHAREHOLDERS
                                   UNDERTAKING
                     (BEING SUPPLEMENTAL TO THE SHAREHOLDERS
                        UNDERTAKING DATED 1ST JULY, 1998
                               AS SUPPLEMENTED BY
              (1) THE FIRST SUPPLEMENTAL SHAREHOLDERS UNDERTAKING
                          DATED 16TH DECEMBER, 1998 AND
              (2) THE SECOND SUPPLEMENTAL SHAREHOLDERS UNDERTAKING
                            DATED 9TH NOVEMBER, 1999)

              ----------------------------------------------------




                                ALLEN & GLEDHILL,
                           36, ROBINSON ROAD, #18-01,
                                   CITY HOUSE,
                                SINGAPORE 068877.

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                                 C O N T E N T S

<TABLE>
<CAPTION>
CLAUSE       HEADING                                            PAGE
------       -------                                            ----
 <S>         <C>                                                <C>


  1.         INTERPRETATION                                       2

  2.         AMENDMENTS TO SHAREHOLDERS UNDERTAKING               2

  3.         REPRESENTATIONS AND WARRANTIES                       3

  4.         INCORPORATION                                        4

  5.         CONFIRMATION                                         4

  6.         GOVERNING LAW AND JURISDICTION                       4

</TABLE>
<PAGE>   3

     T H I S   T H I R D   S U P P L E M E N T A L   U N D E R T A K I N G
is made on 14th December, 2000  B E T W E E N:-

(1)  CHARTERED SILICON PARTNERS PTE LTD (the "Borrower");

(2)  CHARTERED SEMICONDUCTOR MANUFACTURING LTD, EDB INVESTMENTS PTE LTD and
     AGILENT TECHNOLOGIES EUROPE B.V. (together, the "Shareholders"); and

(3)  ABN AMRO BANK N.V., SINGAPORE BRANCH, as agent for and on behalf of the
     Banks defined below (in such capacity, the "Agent", which expression shall
     include any of its successors in such capacity),

and is supplemental to a Shareholders Undertaking (the "Shareholders
Undertaking") dated 1st July, 1998 made between (1) the Borrower, (2) Chartered
Semiconductor Manufacturing Ltd, EDB Investments Pte Ltd and Hewlett-Packard
Europe B.V., as shareholders, and (3) the Agent, as supplemented by (a) the
First Supplemental Shareholders Undertaking (the "First Supplemental
Undertaking") dated 16th December, 1998 made between the parties to the
Shareholders Undertaking and (b) the Second Supplemental Shareholders
Undertaking (the "Second Supplemental Undertaking") dated 9th November, 1999
made between (i) the Borrower, (ii) the Shareholders, (iii) Hewlett-Packard
Europe B.V., as retiring shareholder, and (iv) the Agent.


     W H E R E A S:-

(A)  Pursuant to a Credit Agreement (the "Credit  Agreement") dated 12th
March, 1998 made between (1) the Borrower, as borrower, (2) ABN AMRO
Bank  N.V., Singapore Branch, Bayerische Landesbank Girozentrale,
Singapore Branch, Citibank, N.A., Singapore Branch, Overseas Union Bank
Limited and The Sumitomo Bank, Limited, Singapore Branch, as arrangers,
(3) the Guarantor Banks named therein (the "Guarantor Banks"), as guarantor
banks, (4) the Lending Banks named therein (the "Lending  Banks"), as lending
banks, (5) the Agent, as agent, and (6) ABN AMRO Bank N.V., Singapore Branch,
as security trustee, the Guarantor Banks agreed to grant to the Borrower a
S$236,800,000 guarantee facility (the "Guarantee Facility") and the Lending
Banks agreed to grant to the Borrower a US$143,200,000 term loan facility (the
"Term Loan Facility"), upon the terms and subject to the conditions of the
Credit Agreement.

(B)  The Credit Agreement as amended by (1) a first supplemental agreement
(the "First Supplemental Agreement") dated 14th December, 1998 made between the
parties to the Credit Agreement, upon the terms and subject to the conditions of
the First Supplemental Agreement, and (2) a second supplemental agreement (the
"Second Supplemental Agreement") dated 9th November, 1999 made  between the
parties to the Credit Agreement, upon the terms and subject to the conditions of
the Second Supplemental Agreement, has been further amended  by a third
supplemental agreement (the "Third Supplemental Agreement") dated 14th
December 2000 made between the parties to the Credit Agreement,  upon the terms
and subject to the conditions of the Third Supplemental Agreement, on, inter
alia, the condition that the Borrower and the Shareholders deliver this
Supplemental Undertaking executed by each of them to the Agent.


     I T   I S   A G R E E D  as follows:

1.   INTERPRETATION

(A)  All terms and references used in this Supplemental Undertaking and which
     are defined or
<PAGE>   4
                                       2

construed in the Credit Agreement (as supplemented by the First Supplemental
Agreement, the Second Supplemental Agreement and the Third Supplemental
Agreement), the First Supplemental Agreement, the Second Supplemental Agreement,
the Third Supplemental Agreement, the Shareholders Undertaking (as supplemented
by the First Supplemental Undertaking and the Second Supplemental Undertaking),
the First Supplemental Undertaking and the Second Supplemental Undertaking but
are not defined or construed in this Supplemental Undertaking shall have the
same meaning and construction in this Supplemental Undertaking. All references
in this Supplemental Undertaking to the Credit Agreement shall be to the Credit
Agreement as amended, supplemented or modified by the First Supplemental
Agreement, the Second Supplemental Agreement and the Third Supplemental
Agreement. All references in this Supplemental Undertaking to the Shareholders
Undertaking shall be to the Shareholders Undertaking as amended, supplemented or
modified by the First Supplemental Undertaking and the Second Supplemental
Undertaking.

(B)  The headings in this Supplemental Undertaking are inserted for convenience
only and shall be ignored in construing this Supplemental Undertaking. Unless
otherwise stated, references to the "Clauses" are to be construed as references
to the clauses of this Supplemental Undertaking.

2.   AMENDMENTS TO SHAREHOLDERS UNDERTAKING

     Each of the Borrower, the Shareholders and the Agent agree that with effect
from the Effective Date (as defined in the Third Supplemental Agreement), the
Shareholders Undertaking shall be amended as follows:-

     (1)  Recital (A) to the Shareholders Undertaking shall be deleted in its
          entirety and substituted with the following new Recital:-

          "(A)     By a Credit Agreement (the Credit Agreement as amended by the
          First Supplemental Agreement (as defined below), the Second
          Supplemental Agreement (as defined below) and the Third Supplemental
          Agreement (as defined below), collectively, the "Credit Agreement")
          dated 12th March, 1998 made between (1) the Borrower, as borrower, (2)
          ABN AMRO Bank N.V., Singapore Branch, Bayerische Landesbank
          Girozentrale, Singapore Branch, Citibank, N.A., Singapore Branch,
          Overseas Union Bank Limited and The Sumitomo Bank, Limited, Singapore
          Branch, as arrangers, (3) the Guarantor Banks named therein (the
          "Guarantor Banks"), as guarantor banks, (4) the Lending Banks named
          therein (the "Lending Banks"), as lending banks, (5) the Agent, as
          agent, and (6) ABN AMRO Bank N.V., Singapore Branch (the "Security
          Trustee"), as security trustee, the Guarantor Banks agreed to grant to
          the Borrower a S$236,800,000 guarantee facility and the Lending Banks
          agreed to grant to the Borrower a US$143,200,000 term loan facility,
          upon the terms and subject to the conditions of the Credit
          Agreement.";

     (2)  Clause 1(A) of the Shareholders Undertaking shall be amended as
          follows:-

          (a)  by inserting the following new definitions:-

               ""Third Supplemental Agreement" means the third supplemental
               agreement dated, December 14, 2000 between the parties to the
               Credit Agreement, being supplemental to the Credit Agreement as
               supplemented by the First Supplemental Agreement and the Second
               Supplemental Agreement;"; and
<PAGE>   5
                                       3

               ""Trust Deed" means the trust deed dated 28th September, 2000
               made between (1) the Borrower and (2) the Security Trustee;";

               (b)  the definition of "Senior Indebtedness" shall be amended by
                    inserting the words "(which, for the avoidance of doubt,
                    excludes the Phase 2 Financing Documents (as defined in the
                    Trust Deed))" immediately after the words "Financing
                    Documents" appearing in the last line thereof; and

               (c)  the definition of "Total Indebtedness" shall be amended by
                    inserting the words "(which, for the avoidance of doubt,
                    excludes the Phase 2 Financing Documents (as defined in the
                    Trust Deed))" immediately after the words "Financing
                    Documents" appearing in the last line thereof;

          (3)  Clause 2(A)(2) of the Shareholders Undertaking shall be amended
               by substituting the words "in excess of 1:1" appearing in line 2
               thereof with the words "in excess of 2.6:1";

          (4)  Clause 2(A)(3) of the Shareholders Undertaking shall be amended
               by substituting the words "Clause 16(16)(b) or Clause 16(16)(c)"
               appearing in line 2 thereof with the words "Clause 16(16)(a) or
               Clause 16(16)(b)";

          (5)  Clause 5(A)(9) of the Shareholders Undertaking shall be amended
               as follows:-

               (a)  by deleting the words "or Potential Event of Default"
                    appearing in line 2 thereof; and

               (b)  by inserting the words "and is continuing" immediately after
                    the word "occurred" appearing in line 2 thereof;

          (6)  Clause 5(B)(2)(a) of the Shareholders Undertaking shall be
               amended by substituting the word "Singapore" appearing in line 4
               thereof with the words "the United States of America";

          (7)  Clause 5(B)(2)(c) of the Shareholders Undertaking shall be
               amended by substituting the word "Singapore" appearing in line 2
               thereof with the words "the United States of America";

          (8)  Clause 8(C)(2) of the Shareholders Undertaking shall be amended
               by substituting the words "paragraph (2)" appearing in line 1
               thereof with the words "paragraph (1) above"; and

          (9)  Clause 14(E) of the Shareholders Undertaking shall be amended by
               substituting the words "(now of 438B, Alexandra Road, #05-05,
               #05-07/12, Alexandra Technopark B, Singapore 119968, Attention:
               Legal Counsel)" appearing in lines 2 and 3 thereof with the words
               "(now of 438, Alexandra Road, #11-01/04, Alexandra Point,
               Singapore 119958, Attention: The Regional Legal Counsellor)".

3.   REPRESENTATIONS AND WARRANTIES

     Each of the Borrower and the Shareholders represents and warrants to and
for the benefit of the Agent that:-
<PAGE>   6
                                       4

          (1)  all action, conditions and things required to be taken, fulfilled
               and done (including the obtaining of any necessary consents, if
               applicable) in order (a) to enable it lawfully to enter into,
               exercise its rights and perform and comply with its obligations
               under this Supplemental Undertaking, (b) to ensure that those
               obligations are valid, legally binding and enforceable, and (c)
               to make this Supplemental Undertaking admissible in evidence in
               the courts of Singapore and the Netherlands have been taken,
               fulfilled and done;

          (2)  its entry into, exercise of its rights and/or performance of or
               compliance with its obligations under this Supplemental
               Undertaking do not and will not violate, or exceed any power or
               restriction granted or imposed by, (a) any law to which it is
               subject or (b) its Memorandum and Articles of Association;

          (3)  its obligations under this Supplemental Undertaking and the
               Shareholders Undertaking (as amended by this Supplemental
               Undertaking) are valid, binding and enforceable; and

          (4)  it is not in breach of any of its obligations under the
               Shareholders Undertaking.


4.   INCORPORATION

(A)  The Shareholders Undertaking and this Supplemental Undertaking shall be
read and construed as one document and this Supplemental Undertaking shall be
considered as part of the Shareholders Undertaking and, without prejudice to the
generality of the foregoing, where the context so allows, references in the
Shareholders Undertaking to "this Agreement", howsoever expressed, shall be read
and construed as references to the Shareholders Undertaking as amended, modified
or supplemented by the First Supplemental Undertaking, the Second Supplemental
Undertaking and this Supplemental Undertaking.

(B)  Except to the extent expressly amended by the provisions of this
Supplemental Undertaking, the terms and conditions of the Shareholders
Undertaking and all other instruments and agreements executed, delivered or
entered into thereunder or pursuant thereto are hereby confirmed and shall
remain in full force and effect.

5.   CONFIRMATION

     Each of the Shareholders hereby irrevocably and unconditionally consent to
the amendments to the provisions of the Credit Agreement in the manner set out
in the Third Supplemental Agreement and hereby confirm that the Shareholders
Undertaking remains in full force and effect and is binding on each of the
Shareholders and shall continue in full force and effect and be binding on each
of the Shareholders notwithstanding the amendments to the Credit Agreement in
the manner provided in the Third Supplemental Agreement.

6.   GOVERNING LAW AND JURISDICTION

(A)  This Supplemental Undertaking shall be governed by, and construed in
accordance with, the laws of Singapore.
<PAGE>   7
                                       5

(B)    For the benefit of the Agent and each Bank, all the parties irrevocably
agree that the courts of Singapore are to have jurisdiction to settle any
disputes which may arise out of or in connection with this Supplemental
Undertaking and that, accordingly, any legal action or proceedings arising out
of or in connection with this Supplemental Undertaking ("Proceedings") may be
brought in those courts and each of the Borrower and the Shareholders
irrevocably submits to the jurisdiction of those courts.

(C)    Nothing in this Clause shall limit the right of the Agent and/or any Bank
to take Proceedings against the Borrower or any of the Shareholders in any other
court of competent jurisdiction nor shall the taking of Proceedings in one or
more jurisdictions preclude the Agent and/or any Bank from taking Proceedings in
any other jurisdiction, whether concurrently or not.

(D)    Each of the Borrower and the Shareholders irrevocably waives any
objection which it may at any time have to stipulating the venue of any
Proceedings in any court referred to in this Clause and any claim that any such
Proceedings have been brought in an inconvenient forum.

(E)    ATE irrevocably appoints Agilent Technologies Singapore Pte Ltd (now of
438, Alexandra Road, #11-01/04, Alexandra Point, Singapore 119958, Attention:
The Regional Legal Counsellor) to receive, for it and on its behalf, service of
process in any Proceedings in Singapore. Such service shall be deemed completed
on delivery to the process agent (whether or not it is forwarded to and received
by ATE). If for any reason the process agent ceases to be able to act as such or
no longer has an address in Singapore, ATE irrevocably agrees to appoint a
substitute process agent acceptable to the Agent, and to deliver to the Agent a
copy of the new agent's acceptance of that appointment, within 30 days. Nothing
shall affect the right to serve process in any other manner permitted by law.

(F)    Each of the Borrower and the Shareholders irrevocably and generally
consents in respect of any Proceedings anywhere to the giving of any relief or
the issue of any process in connection with those Proceedings including, without
limitation, the making, enforcement or execution against any assets whatsoever
(irrespective of their use or intended use) of any order or judgment which may
be made or given in those Proceedings.

(G)    Each of the Borrower and the Shareholders irrevocably agrees that, should
the Agent or any Bank take any Proceedings anywhere (whether for an injunction,
specific performance, damages or otherwise), no immunity (to the extent that it
may at any time exist, whether on the grounds of sovereignty or otherwise) from
those Proceedings, from attachment (whether in aid of execution, before judgment
or otherwise) of its assets or from execution of judgment shall be claimed by it
or on its behalf or with respect to its assets, any such immunity being
irrevocably waived. Each of the Borrower and the Shareholders irrevocably agrees
that it and its assets are, and shall be, subject to such Proceedings,
attachment or execution in respect of its obligations under this Supplemental
Undertaking.
<PAGE>   8
                                       6

     I N  W I T N E S S  W H E R E O F  this Supplemental Undertaking has been
entered into on the date stated at the beginning.


The Shareholders

The Common Seal of                          )
CHARTERED SEMICONDUCTOR                     )
MANUFACTURING LTD                           )                       affixed seal
was hereunto affixed                        )
in the presence of:-                        )


         Sd. Lim Ming Seong                  Director
--------------------------------------------


         Sd. Nancy Tan See Sin               [Director]/Secretary
--------------------------------------------


60, Woodlands Industrial Park D,
Street 2,
Singapore 738406.


Fax Number: 360 4970
Attention: Legal Department


The Common Seal of                          )
EDB INVESTMENTS PTE LTD                     )                       affixed seal
was hereunto affixed                        )
in the presence of:-                        )


         Sd. Philip Yeo Liat Kok             Director
--------------------------------------------


         Sd. Ho Tze Wei Monica               [Director]/Secretary
--------------------------------------------

250, North Bridge Road,
#27-04, Raffles City Tower,
Singapore 179101.

Fax Number: 3362503
Attention: General Manager
Signed, Sealed and Delivered                )
by       Sd. Antoine Pierre Chavan          )
   -----------------------------------------
<PAGE>   9
                                       7

for and on behalf of                        )                       affixed seal
AGILENT TECHNOLOGIES EUROPE B.V.            )
in the presence of:- Sd.Anne Jaquenod       )



Startbaan  16,
1187  XR  Amstelveen - Postbus 412
1180  AK  Amstelveen
The Netherlands.

with copy to:-

European Legal Counsel
Agilent Technologies Europe B.V.,
Meyrin Branch,
39, rue de Veyrot,
CH-1217 Meyrin 1/Switzerland.

Fax Number: 41 22 780 6952
Attention: The European Legal Counsel


The Borrower

The Common Seal of                          )
CHARTERED SILICON PARTNERS PTE LTD          )                       affixed seal
was hereunto affixed                        )
in the presence of:-                        )


         Sd. Chia Song Hwee                 Director
--------------------------------------------


         Sd. Nancy Tan See Sin              [Director]/Secretary
--------------------------------------------

60, Woodlands Industrial Park D,
Street 2,
Singapore 738406.

Fax Number: 360 4970
Attention: Legal Department
<PAGE>   10
                                       8

The Agent

Signed, Sealed and Delivered by             )
Ronald Low and Paul Hodgson as              ) Sd. Ronald Low
attorneys for and on behalf of              )                       affixed seal
ABN AMRO BANK N.V.,                         )
 SINGAPORE BRANCH                           ) Sd. Paul Hodgson
in the presence of:- Pauline Low            )

                                              Sd. Pauline Low


63, Chulia Street, 5th Floor,
Singapore 049514.

Fax Number: 536 7816
Telex Number: RS 24396
Attention: Ms Sally Loh / Ms Patricia Teo