JOINT FILING AGREEMENT

                                                                      EXHIBIT 15


                             JOINT FILING AGREEMENT

         This will confirm the agreement by and among all of the undersigned
that this Amendment No. 4 to Schedule 13D on or about this date with respect to
the beneficial ownership by the undersigned of ChipPAC, Inc. is being, and any
and all amendments to such Schedule may be, filed on behalf of each of the
undersigned. This Agreement may be executed in two or more counterparts, each of
which will be deemed an original, but all of which together shall constitute one
and the same instrument.

Dated:  February 20, 2004

                                      CITICORP MEZZANINE III, L.P.
                                      By:  Citicorp Capital Investors Limited,
                                           its General Partner

                                      By:      /s/ Xxxxx X. Xxxxx
                                         ---------------------------------------
                                         Name:   Xxxxx X. Xxxxx
                                         Title:  President


                                      CITICORP CAPITAL INVESTORS, LIMITED

                                      By:      /s/ Xxxxxxx X. Xxxxx
                                         ---------------------------------------
                                         Name:   Xxxxxxx X. Xxxxx
                                         Title:  Vice President


                                      CITICORP VENTURE CAPITAL LTD.

                                      By:      /s/ Xxxxxxx X. Xxxxx
                                         ---------------------------------------
                                         Name:   Xxxxxxx X. Xxxxx
                                         Title:  Vice President and
                                                 Assistant Secretary


                                      CITIBANK, N.A.

                                      By:      /s/ Xxxxxx X. Xxx
                                         ---------------------------------------
                                         Name:   Xxxxxx X. Xxx
                                         Title:  Assistant Secretary




                                      CITICORP

                                      By:      /s/ Xxxxxx X. Xxx
                                         ---------------------------------------
                                         Name: Xxxxxx X. Xxx
                                         Its:  Assistant Secretary


                                      CITIGROUP HOLDINGS COMPANY

                                      By:      /s/ Xxxxxx X. Xxxxxxx
                                         ---------------------------------------
                                         Name: Xxxxxx X. Xxxxxxx
                                         Its:  Assistant Secretary


                                      CITIGROUP INC.

                                      By:      /s/ Xxxxxx X. Xxx
                                         ---------------------------------------
                                         Name: Xxxxxx X. Xxx
                                         Its:  Assistant Secretary