1. VHDI Vacuum Lamination
JC Yun 6/1/06

2. Lamination Procedure For details refer to Doc DB #1009
Plasma Cleaning for VHDI dropped
---simple tests show the weak link is wafer to glue
Plasma Cleaning is also dropped for Si wafer
--- John’s tests show no peel strength improvement for Si wafer to glue bonding

3. Overpressure heating process
Since the vacuum pressure alone could not remove some deformations of 2x VHDI’s – we built a press to remove deformation as much as we could.
3 atmospheric over pressure at 70 degree Celsius at peak. ( 3 hour preheat, 4 hour ramping, overnight cool down under pressure – no vacuum)
The press uses 230 psi N2 gas – 5”sq cylinder.
Safety features:
--- relief valve (260psi)
--- flow restrictor (100cc/min)
--- vacuum pump will remove accidental pressure buildup in the oven and for faster pressure build up the door latch is removed.

4. VHDI Preproduction
5 VHDI were laminated and 1 VHDI is being laminated.
- 4 VHDI laminated with identical process ( two 2x4, two 2x5)
- Minor changes in technique
clam shell vacuum fixture was replaced by the existing lamination station – this eliminates transfer operations between the lamination station to clam shell vacuum fixture 8 times a day
- 1 VHDI (2x3) laminated with the simplified method
- 1 VHDI (2x3) is being laminated in oven

5. Discussions
The process is tuned to be 1 person operation for 2 laminations a day.
The preproduction VHDI laminations show improvement with more pressure (before dicing)
-- creases became smaller
Heat sink with water layer between a glass plate and a VHDI when soldering capacitors --- seems helping
We need to dice, visual inspection and electrical test ASAP.