1. Presentazione Nuovo Progetto Gr. V (ACTIVE - Call 2014)
Lucio Pancheri, Gian-Franco Dalla Betta
DII, Università di Trento
INFN – Padova, Gruppo Collegato di Trento
Tel.: ,

2. ACTIVE: “Atlas Cms Together for InnoVative pixEl”
Exploit strategic and synergic collaboration between ATLAS / CMS INFN groups together with national companies (FBK, Selex) to increase impact and visibility in the Pixel Upgrades for HL-LHC
Development of ultra-radiation hard modules with low material budget (thinner 3D sensors, thinner ROCs, optimized Bump Bonding) for phase 2 ATLAS/CMS upgrades
Front-End roadmap drives
sensor design and
hybridization
CERN-LHCC
Proposal (RD on 65nm)
just approved by LHCC
LP & GFDB Consiglio di Sezione INFN – PD Padova, 27 Giugno 2013

3. Pixel R&D – Technology Trends
Requirements for Pixels (respect to IBL “HL-LHC upgrade 1.5”):
Front-End: x4 dose, x4 rate per unit area, 1/2 – 1/3 pixel size
Sensor: x4 dose, smaller charge at end of life (lower noise → lower discriminator threshold), must be thinner to compete with smaller pixels size
Bump-bonding: x4 number of bumps/chip (>100k), same minimum pitch (50µm)
Off-detector & R/O: high speed link everywhere (GBT on DT, ethernet (?) off-DT), move processing power from ROD: use commercial processors, PCIe, network technologies (this is where commercial world goes)
Slide from G. Darbo
Dose
MGy / neqcm-2
Pixel size
(µm)
Sensor & thickness
FE Chip / FE link rates
LHC
1 / 1x1015
50x400 (ATLAS)
100x150 (CMS)
2D – 250 µm
100 MHz/cm2
40 Mb/s
LHC Phase I (IBL)
2.5 / 5x1015
50x250 (ATLAS)
2D (200 µm)
3D (230 µm)
400 MHz/cm2
320 Mb/s
HL-LHC (Phase II)
10 / 2x1016
25x150 (?)
2D, 3D, (Diamond), MAPS (outer layers)
1-2 GHz/cm2
1-3 Gb/s
Technology watch
Thresh./coll. charge
Needed charge / hybridization / Trigger-Readout
3D: thin sensors, small pixels, charge multiplication (?)
MAPS: new (cheap) technology, radiation
DT-link: GBT (9.6 Gb/s)
Off-DT: ROD architecture & network switch tech.

4. 3D pixel sensor developments Funded by CSN5 (TREDI/TRIDEAS)
Process and design aspects
Fully double-sided process
No support wafer (substrate bias from the back side)
Empty columns, with 12 um diameter and 230 um thickness
Slim edge (200 um for IBL,
also proved down to 100 um)
Temporary metal for I-V tests on wafer
Main results
Tested with FE-I3, FE-I4 and CMS ROCs (laboratory and beam test)
Qualified for ATLAS IBL: >98% efficiency
for 15º tracks at 160 V after 5x1015 neq/cm2
IBL production at FBK with >50% yield
Deep understanding of sensor behavior
C. Da Via, et al.,
NIMA 694 (2012) 321
G.F. Dalla Betta, et al.,
JINST 7 (2012) C10006
LP & GFDB Consiglio di Sezione INFN – PD Padova, 27 Giugno 2013

5. Implications for future pixels
Smaller pixel size in future ROCs (e.g., 150 x 25 mm2) requires a thinner sensor (or at least the collecting charge thickness) to take advantage of the high-pixel spatial resolution.
Smaller inter-electrode distance for radiation hardness
Both lead to higher column density and bump density
Narrower electrodes desirable for higher geometrical efficiency and lower capacitance
This also calls for thinner substrates given a constant column aspect ratio with DRIE
Thinner substrates also help with electrode (at least partial) filling with poly-Si to obtain some efficiency (also using oxygen-free doping gas)
G.-F. Dalla Betta Consiglio di Sezione INFN – PD Padova, 27 Giugno 2013

6. Present status of FBK technology
FBK production line upgrade from 4” to 6” wafers completed
Activity restarted in Spring 2013 with internal test batches
6” allows for higher production volumes (>2x area on wafer)
and lower costs per sensor
DRIE upgrade with a thin ceramic edge protection will simplify the process and increase the mechanical yield
BUT
Need to learn how to process thin wafers on 6” (what is the limit ? Wafer procurement below 275 um is difficult)
Double-sided 3D process might not be the best option (or not at all feasible) for thin sensors  need to explore single-sided alternatives (including epitaxial wafers).
G.-F. Dalla Betta Consiglio di Sezione INFN – PD Padova, 27 Giugno 2013

7. Work Package 1 : new 3D pixels
Fabrication on 6” wafers with thinner active region
Technology and design to be optimized and qualified for extreme radiation hardness (2x1016 neq/cm2)
Smaller pixels, narrower electrodes, reduced inter- electrode distance, very slim (or active) edges, …
Pixel design compatible with present (for testing) and future
(65nm) FE chips of ATLAS and CMS
Support wafer (or substrate for epi) removal to be engineered
Can we apply bias from the back-side ? (would give important advantage for sensor assembly)
Sensor thickness of choice (depending on signal/threshold) ?
- 150 mm: still feasible with “passive” sensor
- below 100 mm: calls for charge multiplication …
G.-F. Dalla Betta Consiglio di Sezione INFN – PD Padova, 27 Giugno 2013

8. Charge multiplication in thin 3D sensors
M. Povoli et al.,
submitted to NIMA
70 mm thickness
LP & GFDB Consiglio di Sezione INFN – PD Padova, 27 Giugno 2013

9. TCAD study: expected performance M. Povoli et al., submitted to NIMA
LP & GFDB Consiglio di Sezione INFN – PD Padova, 27 Giugno 2013

10. Riassunto FTE 2014 Progetto \ Persona Ruolo FTE
Gian-Franco Dalla Betta PA
30% (resp)
Giovanni Verzellesi PO
30%
Lucio Pancheri
RTD-A
40%
Ekaterina Panina
Dott.
50%
Leo Huf Campos Braga
Totale FTE
2.00
+ Due nuovi dottorandi da associare entro fine anno
LP & GFDB Consiglio di Sezione INFN – PD Padova, 27 Giugno 2013

11. Riassunto richieste 2014 Voce Richiesta Missioni :
- Riunioni tecniche e di coordinamento
- Attività di test presso altri partner
1.5
Consumabili:
- Materiali x Laboratorio Test
- Wafers (SOI / epi) o wafer bonding
- Fabbricazione 1 lotto sensori FBK
(prezzo 2200 Euro/lito eq.)
2.0
10.0
26.4
Totale (k€)
41.4
Nessuna richiesta per officine
LP & GFDB Consiglio di Sezione INFN – PD Padova, 27 Giugno 2013