13 Dec. 2007 Switched Capacitor DCDC Update --- M. Garcia-Sciveres 1

Pixel integrated stave concepts

Valencia 2007 SLHC workshop

13 Dec. 2007 Switched Capacitor DCDC Update --- M. Garcia-Sciveres 2

Introduction

• We now have modules on staves, how is the integrated stave approach different?

• What are the schemes that have been proposed? – Common requirements for the active elements

• How much material or CHF can be saved?

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Module on stave vs. integrated stave

• Present modules are fully functional detectors complete with control chip and cable

• Present stave is purely mechanical• In an integrated stave approach electrical services are

combined with the mechanics, and what is loaded on this is not a stand-alone item.

• Consensus emerging to move control functions to end of stave (stave control chip) and to load “bare modules” (all silicon flip chip assemblies on stave).

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88mm

37.5mm

24.4mm

SCC power SCC data

SCC data

Examples from BL workshop

SP stave example (not maximally integrated)

Fully integrated stave

Monolithic structure

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Single chip vs. multi-chip bare module

• 3D sensor processing has introduced the possibility of active edges as a natural byproduct.– But active edges can also be implemented on planar sensors

• If active edges are used, multi-flip chip assembly is an unnecessary complication at non-trivial added cost– There is no acceptance to be gained by using a big sensor tile vs.

smaller active edge tiles– Sensor production and flip chip are cheaper for single-chip

assemblies than multi-chip assemblies, if nothing else because the yield is higher in both cases.

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Shingling along Z

• Mechanical structures proposed at BL workshop all showed flat surfaces (maybe not intended as final, but nevertheless)=> no shingling along Z

• This helps thermal performance and manufacturability

• Active edges (or 2-sided staves) are required to avoid shingling and preserve full acceptance.

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Assembly flow simplificationWafer probe

Bump deposition,Thin and dice

Chip probe/select

16-to-1 Flip chip

Bare module probe

Module assembly

Module full test

Stave/sector test

Stave/sector assembly

rework

NOWSIMPLER

wafer probe

1-to-1 flip-chip

SC module full probe

Stave/sector assembly

Stave/sector test

Higher level of integration at IC stage: no separate “module control chip”

More standard and higher yield 1 to 1 bump bonding: no need for ultra high KGD yield.

Bump deposition,Thin and dice

Toss bad ones

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Outer layers

• 3-D sensors and therefore active edges apply naturally to B-Layer

• But many advantages of active edges are more important for outer layers, where cost is critical:– Cost savings from using single chip modules and no shingling– Simplified assembly flow (faster and cheaper)

• Integrated stave using SC modules is therefore a good model for entire detector– Readout modularity needs to be studied for outer layers.

• Full development of active edges even for planar sensors in important for pixel upgrade!

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The integrated stave conceptual parts(examples can be replaced by equivalent function)

Signal cable with 24 flaps before lamination. Could also be multiple cables.

End of stave card could be built-inStave controller chip goes here

Al power planes added to signal cable. May contain DC-DC converters at a few points, or serial power taps.

Mechanical support with cooling.

Combine all the above and test. Then add SC modules.

Tab wraps around and is w-bonded to SC module

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End of stave card I/O

24

24

24

24

24

24

40MHz clock 40MHz clock bar

40MHz command

40MHz command bar

160MHz data

160MHz data bar

Clock fanout

End of stave cardTraces on flex~15m miniature

coax to PP2 40MHz clock

1GHz command

2GHz data

2GHz data

LV power (eg)

command De-serializer

2 Data serializers

Power at “HV”12-24DC-DC

4-12HV bias groups 4-12HV bias groups

3Muxed NTCs

Twisted pairs

NTC mux

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NTCs for independent monitoring AND safety

Ainterlock

VDCS

next

MuxSenseIC

NTC1

NTC2

NTC3

NTCn

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Material savings

• Items no longer used:– Module control chip– Module pigtail connectors– Shingled carbon surface

• Lighter items– Power conductors

• Less massive if SP or DC-DC• Or could tolerate larger Vdrop if DCDC placed at ends of stave.

– Mechanical structure• See mechanics pixel talk Thu. New developments not central to integrated stave

• New items needed– DC-DC (unless placed only at ends) or SP signal level shifters & control.

• Want even more reductions?– See monolithic structures tomorrow.

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Conclusion

• Many ideas, but prototyping is needed to understand details.

• Good start on mechanical items (see tomorrow)

• Not much done on passive electrical components.