1. 1 Pixel Bus Development Atsushi Taketani RIKEN/RBRC 1.Who is working 2.Over view of pixel bus 3. Manufacture process 4. Issues 5. Development / Production Schedule

2. 2 Who is working RIKEN –Design, Founding, and Coordination for PHENIX Soliton R&D –Fine pitch PCB manufacture. –Manufacturing Al bus Hiroshima Kokusai Gakuin University Research Institute of Advanced Technology –Expert of Aluminum for condensed matter physics KEK and their contractor –Parallel effort for R&D

3. 3 ALICE Pixel BUS (a milestone) ALICE Pixel BUS structure 5 to 7 m Al 12 m Polyimide 5 m glue 15 m Al 5 m glue 12 m Polyimide 5 m glue 12 m Polyimide 5 m glue 12 m Polyimide 50 m Al Total radiation length = 0.173 % X 0 5 to 7 m Al 5 m glue 12 m Polyimide 5 m glue Singal1 Singal2 Singal3 Signal 1; (Vertical line) line connected with pixel chip with wire bonding Signal 2; (Horizontal line) connected with vertical line with through hole Signal 3; (for SMD)

4. 4 PHENIX Option Option 1 Option 2 Option 3 Easy (relatively) Aggressive Line spacing; 140 um pitch Material Budget; Cu;Total ~ 0.376 % Al;Total ~ 0.139 % Line spacing; 140 um pitch Material Budget; Cu;Total ~ 0.306 % Al;Total ~ 0.128 % Line spacing; 70 um pitch Material Budget; Cu;Total ~ 0.236 % Al;Total ~ 0.117 % Horizontal 2layer Vertical 2layer Horizontal 2layer Vertical 1ayer Alignment, Through hole Horizontal 1 layer Vertical 1layer Fine pitch

5. 5 Manufacture Process Aluminum Polyimide 1 Glued Polyimide 2 Etching Polyimide 3 Glued Aluminum 4 Through hole 5 Alignment and Etching 6 Gold plating

6. 6 List of Issues Pattern Etching Aluminum fine pitch pattern Through hole Small (~100micron) Filling conductive material Al - Ni - Au plating Making wire bonding pad Alignment of multiple layer Precise alignment

7. 7 Etching Successfully for ALICE PIXEL bus pattern!!! 40 micron width, 120 micron pitch

8. 8 Etching (2) Peal strength is OK by test. 10micron Polyimide + 5micron/15micron Glue (polyimide) + 12 micron Al Almost ready for production for ALICE BUS Possible for 40micron space pattern Possible to produce 5cm*60cm pattern

9. 9 Through Hole (BVH method) Aluminum Polyimide Laser Chemical plating or Vacuum evaporation Tiring now and will have a result on next week

10. 10 Al –Ni-Au plating 1.Al –Ni for hardening ground for wire bonding. Succeeded, I got a sample, sorry for no picture. 2.Ni-Au Trying now and will have a result on next week.

11. 11 Alignment for multilayer bus By using alignment marks by machine By using through halls by human Developing adjustment machine by mid Sep. Polyimide Aluminum Resist Optics Mask Pattern On the movable table

12. 12 Schedule Etching Done Through hall Done by 2 nd week of June Au plating Done by 2 nd week of June Alignment Machine will be ready at mid Sep. Test production on Mid Oct for ALICE Bus Preproduction for PHENIX on Mid Nov.

13. 13 Alternative KEK and their contractor They will produce ALICE BUS on July. But no Al-Ni-Au plating. We are considering Cu version bus for PHENIX electrical test with readout chip and pilot module.