EXHIBIT 10.15

                                    UMC
           OUTLINE OF ESSENTIAL TERMS CONCERNING PROPOSED COMBINATION


13  January  2000


Xilinx
2100  Logic  Drive
San  Jose  California  95124-3400                    fax  (408)  377-6137


     As  requested,  this  term  sheet  outlines  some  essentials  for  your
consideration  in  connection with the pending merger of UMC with United Silicon
Incorporated  (USIC)  and  other  fabs  in  the  UMC  Group:

1.  Xilinx  will  surrender the certificates for the 300,000,000 USIC shares now
held  by  Xilinx  Holding  Three,  and  in exchange will receive 222,222,222 UMC
shares.  These  UMC  shares  will be publicly tradable, subject to a lock-up for
the  period  required  by  the appropriate authorities. (1)

2.   For  so long as Xilinx holds at least ** UMC shares, and commencing January
2000,  UMC  will  offer Xilinx rights of first refusal to a minimum of ** wafers
per month . If Xilinx's holdings fall below ** UMC shares, UMC will offer Xilinx
rights  of  first  refusal  to  capacity  from the UMC Group fabs in a pro rated
amount  equal  to ** . (2)

3.  All wafer purchases will be ** .    In addition, and conditioned upon Xilinx
compliance with its commitments to purchase from the UMC Group during the period
involved:

(a)     **  ;

(b)     **  ;  and

(c)     The parties will strive to meet the business objective to achieve stable
wafer  pricing on a process by process basis (i.e., without abrupt changes which
have  not  been  discussed  and  agreed  in  advance).

4.  **  UMC  will  protect Xilinx confidential information for so long as Xilinx
holds  a  minimum  of  **  UMC  shares  as  follows:

(a)     **  .

(b)     **  .

5.  For  so  long  as  Xilinx continues to hold a minimum of ** UMC shares, ** .

6.   This term sheet outlines all essential issues which UMC and/or Xilinx  feel
need to be documented in a written agreement, other than those obligations which
the  parties  have  under  their  existing non-disclosure, equipment consignment
agreement  and written purchase orders (except however that this term sheet does
not  restate  those  obligations  between  a  company  limited by shares and its
shareholders  under  Taiwan  law).  Notwithstanding  the  foregoing:

(a)     UMC and Xilinx will negotiate in good faith toward a mutually acceptable
arrangement  in  which UMC intends to offer Xilinx capacity in excess of that in
paragraph  2  above.

(b)     UMC  and Xilinx will negotiate in good faith, with input and advice from
qualified  professionals  and  consultants:

     (i)     the  possibility  of  UMC  offering  American  Depository  Receipts
(ADR's)  for  UMC  shares  sometime  before  the  end  of  the  year  2000;  and
     (ii)     the  possibility  of UMC and Xilinx cooperating with respect to an
advanced  European  foundry  operation.

Footnotes:
(1)  This lock up will require deposit of all the issued UMC shares into custody
for  6  months from the completion of the merger.  On the six month anniversary,
50%  of  the  shares (111,111,111) will be released. The remainder of the shares
will  continue  on  deposit (subject to lock up) until the two year anniversary,
when  10%  (~22,222,222  shares)  will be released.  Thereafter, 10% more of the
shares will be released every six months so that by the fourth year anniversary,
all  shares  will  be  released  from  the  deposit.

(2)  Depending upon loading and technology, the actual capacity offered may come
from  fabs  other  than USIC, so long as the technology, quality and service are
essentially  the  same  (or  better).  Wafer counts are designated in eight inch
equivalents.  As  mentioned by Jim Kupec, the quantities within Xilinx' right of
first  refusal  as  stated  in this Outline of Essential Terms are also included
within the "total wafer availability" shown in Exhibit A to the January 11, 2000
letter  from  Mr.  Kupec to Wim Roelandts (letter commit). However, this Outline
remains  valid  regardless  of  Xilinx' compliance with the terms stated in that
letter  commit.  In  other  words,  even if Xilinx does not meet the ** criteria
outlined  in  Jim's  letter commit, UMC will not reduce Xilinx' wafer quantities
below  those  in this Outline except pursuant to paragraph 2 of this Outline, or
as  otherwise  allowed  for  material  breach  by  Xilinx  with  respect  to the
quantities  in  this  Outline.

(3)  **

(4)  **

(5)  **

(6)  **


**Pursuant to a request for confidential treatment, selected information in this
document  has been omitted and separately filed with the Securities and Exchange
Commission.



United  Microelectronics  Corporation                         Xilinx  Inc.

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