1. n-XYTER Hybrid Developments
Christian J. Schmidt et al.,
GSI Darmstadt
JINR, Dubna, Oct. 15th 2008

2. n-XYTER, current workhorse chip for prototyping
workhorse readout chip for detector prototyping
architectural example front-end for DAQ development (self triggered, data driven)
sample ASIC for technological front-end electronics hybrid developments
bonding technology, circuit board technology
thermal management, active cooling concepts
power management (integraly high currents, low voltage, high B-fields, high rad. environment)
very dense mechanical boundary conditions

3. "Simple" FEB for the n-XYTER Starter Kit
A simple hybrid PCB with signal fan-in, ADC and interconnect to SysCore DAQ chain
Allow development of the DAQ chain
Allow the readout of various detector prototypes
Allow to explore the challenges of hybrid development
The September beam time has shown the whole signal chain operative!
Silicon Strip / GEM Gas Detectors --- n-XYTER --- SysCore DAQ System

4. n-XYTER FEB: At the limits of PCB-technology
Interference point of many technologies,
each imposing limiting boundary conditions:
Chip-In-Board solution avoids space eating vias
allows pitch adaptation:
50,7 µm on chip to
PCB side 101,4 µm on two levels

5. n-XYTER FEB: At the limits of PCB-technology
100 µm pitch on PCB is at the limit of PCB technology!
landing area for bonds comes out much smaller than 50 µm
high yield wire bonding technology finds limits at ~65 µm landing space
Chip-In-Board technologically impeeds use of cooling vias
Unplugged vias spoil bonding structures
Plugged vias spoil bonding surface quality
Current Solution: Macroscopic metal inlay underneath the chip realized after PCB manufacturing will give thermal link to cooling infrastructure
FEB-Rev B
FEB-Rev C
 Realize 125 µm pitch on PCB at the expense of more complicated fan-out bonding with Chip-In-Board, two layer bonding and metal in-lay cooling contact
 FEB-Rev D

6. It is all a question of yield!
Wire Bonding Technology:
Maximum bond length ~ 4 mm
Staggered fan-out complicates bonding
Bonding machine determines specs on dimensions of landing space
PCB-Technology
50µ / 50µ shatteres yield
close contact to manufacturer
special solutions (Chip in Board)
metal inlay solution
Home made issues:
-- Cooling strategy:
Wire bonds demand cooling from below
Flip-Chip bump bonds may allow cooling from either side
-- Limitations on Orcad layout tool
-- On Chip bond-pad layout

7. n-XYTER FEB Prototype - GEM-TPC for PANDA
Application foreign to CBM, but high density gas detector read-out, just like CBM-MUCH
First large scale application of n-XYTER: chips on 46 boards. Beam time for the TPC at FoPi: End of 2009
Dimensions: 265 x 103 mm
8 layers
Board status: in production
Slide by Rafal Lalik

8. n-XYTER Quattro Integrated double sided Silicon Baby Sensor Readout
4 n-XYTERs on one PCB
100 x 100 mm2
8 layers
SysCore read-out
complicated mechanical
milling scheme
Status: In production
at ILFA !
Slide by Rafal Lalik

9. STS specific hybrid developments
Hybrid for STS Ladder Modules
Combined challenges with
high density chip assembly needs
sensitive microcable detector interconnect
integrated cooling
integrated powering scheeme in high magnetic fields and rad. env.
Temptatively, a completly different technology comes into play:
Silicon based circuit board
flip chip assembly of XYTERs
high efficiency cooling contacts and hybrid stackability
tap bonding for micro-cables (V. Pugatch, Kiev)
separated potential domain for upper and lower side det. readout

10. Two development lines to be discussed:
STS module based on n-XYTER and PCB technology
primarily to show micro cable performance
4 to 8 chip hybrid, preferably dual side readout
STS module based on n-XYTER and compact flip-chip technology,
Silicon circuit board serves as
efficient cooling contact (cooling from both sides)
pitch adapter to the micro cables
Precise project definition and distribution of workpackages still to be done,
GSI Detectorlab signed up for hybrid development (we will have a new electronics engineer starting in December)
so we should now start this discussion