Title page for ETD etd-082699-110209


Type of Document Master's Thesis
Author Jittinorasett, Suwanna
Author's Email Address puijitti@ee.vt.edu
URN etd-082699-110209
Title UBM Formation on Single Die/Dice for Flip Chip Applications
Degree Master of Science
Department Electrical Engineering
Advisory Committee
Advisor Name Title
Elshabini-Riad, Aicha A. Committee Chair
Besieris, Ioannis M. Committee Member
McGrath, James E. Committee Member
Sergent, Jerry E. Committee Member
Keywords
  • Solder Bump
  • Flip Chip
  • Under Bump Metallurgy (UBM)
  • Single Die
Date of Defense 1999-08-25
Availability unrestricted
Abstract
This thesis presents the low cost process for UBM formation on aluminum pads of single die/dice for Flip Chip applications. The UBM (Under Bump Metallurgy) is required in solder bump structure to provide adhesion/diffusion barrier layer, solder wettable layer, and oxidation barrier layer between the bonding pads of the die and the bumps. Typically, UBM is deposited on the whole wafers by sputtering, evaporation, or electroless plating. These deposition techniques are not practical for UBM formation on single die/dice, thus preventing Flip Chip technology to be applied in applications where the whole wafers are not available. The process presented in this thesis has been developed to overcome this problem. The developed UBM formation process allows the UBM layer to be deposited on a single die, thus eliminating the requirement to have the whole wafer in the deposition process. With the combination of the UBM formation process developed in this work and a suitable bump formation technique, solder bumping on a single die can be achieved, thus making Flip Chip technology available for use in low volume applications and prototyping stages.

The developed UBM formation process consists of two major steps; temporary die attach process and UBM deposition process. The first process is developed using thermoplastic adhesive film. The second process is developed using electroless nickel plating, followed by gold immersion. It has been demonstrated in this thesis that the developed process can be used to form the UBM layer on the die successfully regardless of the die size and the complexity of the die pattern, and that this process does not damage nor affect electrically the sensitive die.

Files
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  Final.pdf 1.23 Mb 00:05:40 00:02:55 00:02:33 00:01:16 00:00:06

Browse All Available ETDs by ( Author | Department )

dla home
etds imagebase journals news ereserve special collections
virgnia tech home contact dla university libraries

If you have questions or technical problems, please Contact DLA.