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                                                                   EXHIBIT 10.20

                                 TESSERA, INC.

                               SECOND ADDENDUM TO
                          TCC MASTER LICENSE AGREEMENT

This Second Addendum Agreement ("Second Addendum") entered into between TESSERA,
INC., a corporation organized under the laws of Delaware ("Tessera") and SHINKO
ELECTRIC INDUSTRIES CO., LTD. a corporation organized under the laws of Japan
("Licensee") shall be effective as of the last date signed below. The parties
to this Second Addendum agree to the following terms:

I.   SUPPLEMENT TO AGREEMENT: This Second Addendum merely supplements certain
     provisions of the TCC Master License Agreement ("Agreement"), entered into
     on January 20, 1994 and the Addendum to the TCC Master License Agreement,
     entered into on November 22, 1994 ("First Addendum"). All provisions,
     including Definitions, contained within the Agreement and the First
     Addendum are therefore incorporated herein. In the event any of the
     provisions of the Agreement, the First Addendum and this Second Addendum
     conflict, the provisions contained in this Second Addendum shall supersede
     the conflicting provisions set forth in the Agreement or the First
     Addendum.

II.  DEFINITIONS:

     A.   The term "Packaging-Related" as applied to any item (including any
information, idea, invention or know-how), means that such item is
substantially related to the physical structures, components and/or stages of
assembly of any IC chip package, including methods for packaging, mounting or
connecting such IC chips. Notwithstanding, any items used for making multi-chip
modules or assemblies ("MCMs") using TCCs, including electrical substrates,
sockets for TCCs, along with heat spreaders and/or related thermal structures
or items which do not relate to said physical structures, components or
assembly stages of IC chip packages are not Packaging-Related.

     B.   The term "Wafer Level Packaging services" means Technology for
manufacturing TCCs using a batch assembly process to attach a plurality of
flexible leads to a corresponding plurality of bond pads on an IC chip, an
array of IC chips, or an undiced wafer by simultaneously gang bonding and
forming such plurality of leads.

     C.   The term "Low Pin Count" applied to any device (TCC, uBGA, or related
packaged IC) means a device with less than one hundred (100) IC bond pad
connections.

     D.   The term "Moderate Pin Count" applied to any device (TCC, uBGA, or
related packaged IC) means a device with IC bond pad connections numbering
greater than those of a Low Pin Count device and less than two hundred and
twenty-five (225).

     E.   The term "High Pin Count" applied to any device (TCC, uBGA, or
related packaged IC) means a device with IC bond pad connections numbering
greater than those of a Moderate Pin Count device and less than five hundred
(500).

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     F.   The term "High Performance" applied to any device (TCC, (u)BGA, or
related packaged IC) means a device with IC bond pad connections numbering
greater than those of a High Pin Count device and less than one thousand (1000).

     G.   The term "Ultra High Performance" applied to any device (TCC, (u)BGA,
or related packaged IC) means a device with IC bond pad connections numbering
one thousand (1000) or greater.

     H.   The term "(u)BGA" is an IC device comprising an IC die and a miniature
chip-sized or chip-scale package made with the possible incorporation of a
protective case surrounding the back and sides of said IC die, including
integral heat spreaders or heat sinks attached to said IC die or case therefor.
A (u)BGA is a type of TCC.

III. ROYALTIES:

     A.   TLS and MCM Royalties. Tessera and Licensee agree that all royalties
due under the Agreement for TLS products remain unchanged. Tessera and Licensee
further agree that any royalties for MCMs due under the Agreement shall now be
calculated as the [*] (as calculated under Section III.B., below) for the TCCs
or (u)BGAs incorporated into such MCM.

     B.   Running Royalties. Licensee shall pay running royalties for the
license of Technology, including applicable Tessera Patents, twice annually (as
called out under "Licensee's Payments and Reports" in the Agreement) to Tessera
during the term of the Agreement. Licensee's total base royalty (subject to the
adjustments of Paragraphs C. and D., below) shall be calculated as the sum of
the following royalties:

          (i).      TCMT. There is [*] for any sale of TCMT permitted hereunder.

          (ii).     Low Pin Count. For sales or other transfers of Low Pin Count
devices, whether manufactured for sale or internal use, the payable royalty
shall be calculated on Licensee's total unit volume of IC bonds, leads, or
equivalent connections made or bonded in Low Pin Count (u)BGAs, TCCs or related
devices. Said base royalty shall be paid in the amount of [*].

          (iii).    Moderate Pin Count. For sales or other transfers of Moderate
Pin Count devices, whether manufactured for sale or internal use, the payable
royalty shall be calculated on Licensee's total unit volume of IC bonds, leads,
or equivalent connections made or bonded in Moderate Pin Count (u)BGAs, TCCs or
related devices. Said base royalty shall be paid in the amount of [*].

          (iv).     High Pin Count. For sales or other transfers or High Pin
Count Devices, whether manufactured for sale or internal use, the payable
royalty shall be calculated on Licensee's total unit volume of IC bonds, leads,
or equivalent connections made or bonded in High Pin Count (u)BGAs, TCCs or
related devices. Said base royalty shall be paid in the amount

* Certain information on this page has been omitted and filed
  separately with the Commission. Confidential treatment has
  been requested with respect to the omitted portions.

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of [*] (US$[*]) [*].

          (v). High Performance. For sales or other transfers of High
Performance devices, whether manufactured for sale or internal use, the payable
royalty shall be calculated on Licensee's total unit volume of IC bonds, leads,
or equivalent connections made or bonded in High Performance (u)BGAs, TCCs or
related devices. Said base royalty shall be paid in the amount of [*].

          (vi). Ultra-High Performance. For sales or other transfers of Ultra
High Performance devices, whether manufactured for sale or internal use, the
payable royalty shall be calculated on Licensee's total unit volume of IC bonds,
leads, or equivalent connections made or bonded in Ultra High Performance
(u)BGAs, TCCs or related devices. Said base royalty shall be paid in the amount
of [*] (US$[*]) [*].

     C.   Adjustments for High Volumes. Royalty payments due Tessera hereunder
shall be adjusted by multiplying Licensee's total base royalty calculated under
Paragraph B. above, by a factor of [*] ([*]) until Licensee has paid Tessera [*]
US DOLLARS (US$[*]) in aggregate royalties, and then by a factor of [*] ([*])
[*] US DOLLARS (US$[*]) [*]. Tessera and Licensee agree that at least once every
three years the parties will review the royalty rates set forth above in the
context of evaluating whether the market price of such products made by Licensee
under the Technology have remained competitive.

     D.   Adjustments for Exchange Rates and Inflation. Tessera and Licensee
agree that in conjunction with the review of royalty rates called for in
Paragraph III., C., above, the parties shall in good faith, jointly determine
equitable adjustments, if any, in Licensee's royalty payments to compensate the
parties solely for the effects of changes in currency exchange rates and/or
inflation in any countries in which Licensee sells items licensed hereunder.

IV.  QUICK TURNS AND PROTOTYPES: Tessera hereby waives any requirement in the
     Agreement for quick turns and prototypes TCC and (u)BGA parts to be built
     exclusively by Tessera. Tessera and Licensee agree that Licensee may take
     and satisfy orders for quick turn and prototype business and that the
     existing royalty reporting requirements under the Agreement shall apply to
     any such satisfied orders.

V.   WAIVER OF OPTIONAL CUSTOMER STRATEGIC PARTNERSHIP PLAN: Tessera hereby
     grants Licensee a waiver of the requirement that Licensee advise and
     distribute to Licensee's Customers the Strategic Partnership Plan (Schedule
     B in the First Addendum).

VI.  SUPPLYING WAFER SCALE PACKAGING SERVICES. Tessera and Licensee agree that
     the "High Performance" classification of Wafer Scale Packaging Services is
     hereby deemed null and void, and that the pin based schedule of royalties
     set forth in this Second Addendum shall apply to any Wafer Scale Packaging
     Services.

* Certain information on this page has been omitted and filed
  separately with the Commission. Confidential treatment has
  been requested with respect to the omitted portions.

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VIII. ENTIRE UNDERSTANDING: This Second Addendum embodies the entire
      understanding between the parties relating to the subject matter hereof,
      whether written or oral, and there are no prior representations,
      warranties or agreements between the parties not contained in this Second
      Addendum. Any amendment or modification of any provision of this Second
      Addendum must be in writing, dated and signed by both parties hereto.

IN WITNESS WHEREOF, the parties hereto have executed and delivered this Second
Addendum as of the last date signed below.

TESSERA, INC.                               SHINKO ELECTRIC INDUSTRIES CO., LTD.

By:  /s/ JOHN W. SMITH                      By:  /s/ SUGIO UCHIDA
   ------------------------------              -------------------------------
Name:  John W. Smith                        Name:  Sugio Uchida
     ----------------------------                -----------------------------
Title: President                            Title: Executive Managing Director
      ---------------------------                 ----------------------------
Date:  7-7-95                               Date:  7-13-95
     ----------------------------                -----------------------------

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                                                                   EXHIBIT 10.21

                                  TESSERA, INC.

                                THIRD ADDENDUM TO
                          TCC MASTER LICENSE AGREEMENT

This Third Addendum Agreement ("Third Addendum") entered into between TESSERA,
INC., a corporation organized under the laws of Delaware ("Tessera") and SHINKO
ELECTRIC INDUSTRIES CO., LTD, a corporation organized under the laws of Japan
("Licensee") shall be effective as of the last date signed below. The parties to
this Third Addendum agree to the following terms:

I. SUPPLEMENT TO AGREEMENT: This Third Addendum merely supplements certain
provisions of the TCC Master License Agreement ("Agreement"), entered into on
January 20, 1994 and the Addendum to the TCC Master License Agreement, entered
into on November 22, 1994 ("First Addendum") and the Second Addendum to the TCC
Master License Agreement ("Second Addendum") entered into on July 13, 1995
(collectively "Combined Agreements"). All provisions, including Definitions,
contained within the Combined Agreements are therefore incorporated herein. In
the event any of the provisions of the Combined Agreements and this Third
Addendum conflict, the provisions contained in this Third Addendum shall
supersede the conflicting provisions. The modifications to the Combined
Agreements as set forth herein are pursuant to the Equitable License provision
of the Agreement and are substantially similar to the terms currently being
negotiated with Amkor Electronics.

II. DEFINITIONS:

       A. The term "Batch Technology" as used herein means Technology including:
(i) any method or result of U.S. Patent Serial Number 08/271,768 (and related
Patents) for bonding or connecting one or more substantially planar
electrically conducting flexible elements to electrical contact(s) on a
substantially planar electrical element such as a semiconductor integrated
circuit, undiced IC wafer, or interconnect substrate, and then forming said
element(s) away from the plane of said contacts in a predetermined fashion into
the flexible electrical lead(s) of a TCC package; (ii) any method or result of
U.S. Patent 5,455,390 (and related Patents) for making and forming one or more
flexible conducting elements on a flexible dielectric film and simultaneously
joining said elements to electrical contacts on a substantially planar
electrical element such as a semiconductor integrated circuit, undiced IC wafer
or interconnect substrate to produce the flexible electrical leads of a TCC
package; and/or (iii) any method or result of further invention or Patent made
or acquired by Tessera during the term hereof covering any batch processing
method for forming or producing and/or connecting flexible electrical leads of a
TCC package. The parties expressly agree that the term "Wafer Level Packaging
services", as it is defined in the Second Addendum, is included in Batch
Technology. The parties further expressly agree that any TCC package made and/or
connected individually on an IC wafer before dicing by traditional wire bonding
methods and/or tape automated bonding ("TAB") gang bonding methods, is NOT
included in Batch Technology.

       B. [*].

* Certain information on this page has been omitted and filed
  separately with the Commission. Confidential treatment has
  been requested with respect to the omitted portions.

                                  Page 1 of 2
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II. LICENSEE RIGHTS - BATCH TECHNOLOGY EXCLUDED. Notwithstanding any language to
the contrary, Batch Technology is excluded from the scope of the licensed
Technology in this Third Addendum and the prior Combined Agreements, and
Licensee's rights herein expressly exclude any right or license to make, use or
sell any TCC or related IC package manufactured by or incorporating Batch
Technology.

III. ROYALTIES:

       A. Base Royalty. As consideration for the modifications to the Combined
Agreements contained herein this Third Addendum, Licensee shall pay a total base
royalty to Tessera in the amount of [*] PERCENT ([*]%) [*] related to TCC
packages licensed hereunder.

       B. Sliding Royalty Scale. Royalty payments due Tessera hereunder shall be
adjusted by multiplying Licensee's total base royalty calculated under Paragraph
A. above, by a [*] ([*]) until Licensee has paid Tessera [*] US DOLLARS (US$[*])
in aggregate royalties, and then by a factor of [*] ([*]) until Licensee has
paid Tessera an additional [*] US DOLLARS (US$[*]) in aggregate royalties.
DISCOUNT FOR PREPAYMENT: Licensee may elect to pay Tessera [*] US DOLLARS
(US$[*]) in lieu of any such Sliding Scale Royalties, in which event said
Licensee will notify and tender such payment to Tessera within six (6) months
from the Effective Date of this Third Addendum.

IV. ENTIRE UNDERSTANDING: This Third Addendum embodies the entire understanding
between the parties relating to the subject matter hereof, whether written or
oral, and there are no prior representations, warranties or agreements between
the parties not contained in this Third Addendum. Any amendment or modification
of any provision of this Third Addendum must be in writing, dated and signed by
both parties hereto.

IN WITNESS WHEREOF, the parties hereto have executed and delivered this Third
Addendum as of the last date signed below.

TESSERA, INC.                           SHINKO ELECTRIC INDUSTRIES CO., LTD.

By: /s/ JOHN W. SMITH                   By: /s/ SUGIO UCHIDA
   --------------------------------        -------------------------------------

Name: JOHN W. SMITH                     Name: SUGIO UCHIDA
     ------------------------------          -----------------------------------

Title: PRESIDENT                        Title: EXECUTIVE MANAGING DIRECTOR
      -----------------------------           ----------------------------------

Date: 5-28-96                           Date: 5-31-'96
     ------------------------------          -----------------------------------

* Certain information on this page has been omitted and filed
  separately with the Commission. Confidential treatment has
  been requested with respect to the omitted portions.

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[TESSERA LOGO]
--------------------------------------------------------------------------------
3099 Orchard Drive San Jose, CA 95134 Phone: (408) 894-0700 Fax: (408) 894-0768

                                                                    FEB 10, 1997

VIA FACSIMILE

Mr. Hidenori Takayanagi
Program Director - Marketing and Sales Planning Div.
Shinko Electric Industries Co. Ltd.
80 Oshimada-Machi
Nagano-shi, 381-22 Japan

RE: TCC License

Dear Takayanagi-San:

Mr. Smith has asked me to follow-up up his recent discussion with you in Japan
regarding the TCC license terms between Tessera and Shinko Electric.

As you know, the Third Addendum to the TCC Master License Agreement gave Shinko
the option to pay Tessera [*] US DOLLARS (US$[*]) in lieu of any Sliding Scale
Royalties, as defined therein. However, this option only remained open for six
months from the date the Third Addendum was signed.

This option has lapsed; however, in the spirit of good will between our
companies, Mr. Smith has authorized me to send this letter extending to Shinko
the option, for an indefinite period of time, to pay Tessera the [*] US DOLLARS
(US$[*]) in lieu of such Sliding Scale Royalties, in which event Shinko shall
notify Tessera and tender such payment and henceforth pay royalties at the [*]
without any such Sliding Scale Royalties. Let me be clear that the lowering of
royalties upon such payment has no retroactive effect on the amount of royalties
paid previous to such payment.

Please contact me if you have any comments or questions regards this matter.

Best regards,

/s/ CHRISTOPHER M. PICKETT
-------------------------------------
Christopher M. Pickett
Director of Intellectual Property

* Certain information on this page has been omitted and filed
  separately with the Commission. Confidential treatment has
  been requested with respect to the omitted portions.

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