1

Plans for Demonstrator Flip Chip Bonding

GTK meeting 9/12/08

2

GeneralBump pad layout as in ALICE/Medipix (see talk by

Massimiliano)

Sensor wafers will be delivered as 4” wafers

Demonstrator chips will be delivered as single dies

Standard processing only possible for sensor wafers (full wafer processes)

Need to develop a procedure for the demonstrator dies

GTK meeting 9/12/08

3

{

GTK meeting 9/12/08

www.fujitsu.com

4P. Riedler/CERN - 26.10.2006

• Dicing of the wafers• Flip chip bonding of a sensor to one (or more) readout chip and reflow

S. Savolainen-Pulli/VTT

}

5

Bump Deposition Simplified scheme

S. Savolainen-Pulli (Pixel 2005 conference)

In standard process done on wafer level

GTK meeting 9/12/08

How to deposit UBM and eventually Pb-Sn on single dies?

Non-standard process!

6

Discussion with VTTFirst meeting February 2008: VTT proposes to

use reverse rework process (transfer Pb-Sn bumps to the dies from a carrier wafer)

Continuing discussion:How to deposit the wettable metal which is

underneath the Pb-Sn on the ROC?How to protect the wire bonding pads?Could the Pb-Sn be skipped on the ROC side at all?

GTK meeting 9/12/08

7

StatusDiscussion on technical matters with VTT

(4/12/08), i.e. proposal to suppress Pb-Sn on ROC

Proposed tentative workplan to have process ready by April when all components will be available

Process development will be done in the coming months using dummies

Order for demonstrator being prepared

Target: 10+10 bonded chips before summerGTK meeting 9/12/08