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

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

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ALICE Pixel BUS (a milestone)• ALICE Pixel BUS structure

5 to 7 m Al12 m Polyimide

5 m glue

15 m Al5 m glue

12 m Polyimide

5 m glue

5 m glue12 m Polyimide

5 m glue

12 m Polyimide

50 m Al

50 m Al

Total radiation length = 0.173 % X0

5 to 7 m Al

5 m glue12 m Polyimide

5 m glue

Singal1

Singal2Singal3

Signal 1; (Vertical line)line connected withpixel chip with wire bonding Signal 2; (Horizontal line) connected with vertical line with through hole Signal 3; (for SMD)

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PHENIX Option

Option 1 Option 2 Option 3

Easy (relatively) Aggressive

Line spacing; 140 um pitchMaterial Budget;Cu; Total ~ 0.376 %Al; Total ~ 0.139 %

Line spacing; 140 um pitchMaterial Budget;Cu; Total ~ 0.306 %Al; Total ~ 0.128 %

Line spacing; 70 um pitchMaterial 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

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Manufacture Process

Aluminum

Polyimide

1 Glued

Polyimide

2 Etching

Polyimide

3 Glued

Aluminum

4 Through hole

5 Alignment and Etching

6 Gold plating

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List of Issues• Pattern Etching

Aluminum fine pitch pattern

• Through holeSmall (~100micron)Filling conductive material

• Al - Ni - Au platingMaking wire bonding pad

• Alignment of multiple layerPrecise alignment

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Etching

Successfully for ALICE PIXEL bus pattern!!!

40 micron width, 120 micron pitch

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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

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Through Hole (BVH method)

Aluminum

Aluminum

Polyimide

Laser

Chemical plating

or

Vacuum evaporation

Tiring now and will have a result on next week

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.

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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

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Schedule

• Etching Done

• Through hall Done by 2nd week of June

• Au plating Done by 2nd 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.

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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.