IEEE NSSMIC 2011 Valencia Spain Wojciech Dulinskiires in

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr Large Area Ultra-Thin Detector Ladders based on CMOS Monolithic Pixel Sensors Wojciech Dulinski IPHC Strasbourg, France on behalf of PLUME, SERVIETTE and CERNVIETTE Collaborations Outline · Short status of MAPS development at IPHC · PLUME: the lightweight ladder based on standard flex PCB · SERVIETTE and CERNVIETTE: ultra-thin chip embedding in plastics project (two different process approach) · Conclusions and prospects 1

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr Monolithic Active Pixel Sensor: effective use of a thin epitaxial layer (10 – 20 µm) for MIP tracking R. T. past present Industrial availability of high resistivity substrate (epi) in a standard CMOS process Fast and more efficient charge collection radiation tolerant MAPS 2

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr Present status of MAPS: just two examples of mature designs Binary, sparsified readout sensor for EUDET beam telescope > 2 cm 2 active area, 0. 7 Mpixel tracker - Medium speed readout (100 µm integration 10 k. Frame/s) - Spatial resolution < 4 µm for a pitch of 18. 4 µm - Efficiency for MIP > 99. 5 % - Fake hit rate < 10 -6 - Radiation hardness > 1013 n/cm 2 (high resistivity epi substrate) - Easy to use, “off-shell” product: used already in several application Mimosa 26 Ultimate: 4 cm 2 sensor for STAR Microvertex upgrade - similar measured tracking performance as Mimosa 26 - Radiation hardness >1014 n/cm 2 with CMOS MAPS attainable? First indications: yes! 3

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr One of the main feature of MAPS Potentially extremely thin (~25 µm of silicon in total, ~0. 027 % X 0), flexible (!) and still fully efficient for MIP tracking! Problem: how to handle, interconnect and at the end built a low mass ladder with such a thin device? 4

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr First real scale exercise: new STAR Microvertex Detector Data taking (1/4 of detector) expected in 2013, full detector installation in 2014 Estimated 0. 37% X 0/ladder. Can we do better? 5

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr Three RD mini-collaborations initiated by IPHC ~2 years ago, in order to develop new methods of ultra-thin ladders construction PLUME, SERVIETTE and CERNVIETTE Collaborations 1 IPHC/IN 2 P 3 Strasbourg, France 5 University of Bristol, UK 6 DESY, Hamburg, Germany 7 University of Oxford, UK 2 IMEC, Leuven, Belgium 3 CMST, University of Gent, Belgium 4 IFK, Goethe University, Frankfurt/M, Germany 8 CERN, Geneva 6

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr PLUME concept: double-sided ladder (ILC compatible) - 2 x 6 Mimosa 26 sensors thinned down to 50 µm - Standard double-side kapton PCB: Cu conductor (20 µm/layer) - Si. C foam (8%) for spacer between layers - Estimated 0. 6 % X 0/two sensor layers 7

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr PLUME prototype: assembling steps bare low mass cable module with 6 sensors complete ladder (2 modules) 8

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr Heat dissipation: moderate air blow seems to solve a lot of “hot spots” problems Electrical parameters (threshold dispersion, fake hit rate) almost unchanged… 9

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr Current status of PLUME prototype: ready for beam tests next week! 10

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr SERVIETTE project: use of UTCP by IMEC… § Stands for : ULTRA THIN FILM CHIP PACKAGING § In short : Ø Off-the-shelf die Ø Thinned down to ± 20 -30 µm Polyimide 2 Ø Packaged between two polyimide foils Ø Metallisation : fan-out Ø Circuit contact through vias Polyimide 1 § Result : Ø Flexible package, no wire bonding Ø Thin : 50 -70 µm Ø Embeddable in commercial flexible PCB - Partner restricted PTW Oct. 2010 - HUMAN++ 11

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr UTCP flow: overview • Polyimide on rigid carrier with release layer (KCl) • Chip thinning • Dispense/spin of BCB • Placement (face up) of IC 60 mm • Photo definable polyimide spinning (20µm)) • Opening vias using lithography • Cleaning of contact pads • Metallization: Ti. W (50 nm) + Cu(1µm) • Electroplating : Cu (5µm) • Lithography to pattern metal • Encapsulation polyimide spinning • Release from carrier 12

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr First results: Mimosa 18 mechanical grade sample Submitted for fabrication more than a year ago, very slow progress since, on stand-by till thinned chip placement problems solved. Aluminum conductor, multiple metal layers and multiple chips still far ahead… 13

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr CERNVIETTE: use of a “standard” flex PCB process for chip embedding in plastic foils (Rui de Oliveira, Serge Ferry) • Gluing between two kapton foils • Opening vias using lithography • Single module: intermediate tests • Metallization: Al (5 -10 µm) • Lithography to pattern metal • Complete ladder assembling, laser cut along sensor edges • Gluing of another kapton foil for deposition of second metal layer 14 14

Wojciech. Dulinski@ires. in 2 p 3. fr IEEE NSS-MIC 2011, Valencia, Spain CERNVIETTE: stack formation Copper 150 µm Polyimide Silicon chip Acrylic glue Polyimide Acrylic glue Copper substrate 1. 5 mm Thin layer of epoxy glue 3 to 10 µm acrylic glue 60 µm

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr CERNVIETTE: processing steps 1 -Gluing at 200 deg, 22 kg/cm 2 under vacuum 2 -Photolithographic method and chemical etching by ethylene diamine to create vias on top of bonding pads 3 -Plasma etching of glue in vias 4 -Aluminium coating by sputtering deposition in vacuum machine 16

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr CERNVIETTE: processing steps 5 -Photolithographic method and etching with phosphoric acid to pattern aluminium layer (strip, pads). Step 1 to 5 can be repeated to create more metal layers and interconnexions 6 -Chemical Etching of copper substrate 17

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr CERNVIETTE: solid state flexible sensor wrapped over cylindrical shape (R=20 mm) and pretty well protected 18

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr Major failure: too short plasma etching of glue layer, no electrical contacts… But excellent metal adhesion and thickness uniformity! Second (corrected) iteration expected to be ready next week 19

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr CERNVIETTE: details of 4 metal layer flex (~0. 12% X 0) Impedance of readout lines (last metal, 100 µm width, 100 µm gap) as a function of kapton thickness: 100 Ω for 60 µm thick kapton (last layer) 20

IEEE NSS-MIC 2011, Valencia, Spain Wojciech. Dulinski@ires. in 2 p 3. fr Conclusions - Construction methods of ultra-light sensor ladders are progressing rapidly, embedding in polymer seems to be a new interesting option - It is at present our preferred solution in order to take full profit from MAPS high precision tracking performances AND to equip with a reasonable budget large area detectors (replacement of silicon strips, tracking calorimeters…) Outlook - Double-sided PLUME module (0. 6 % X 0) fully operational, ready for beam tests starting next month. The next version (Al instead of Cu conductor, less dense Si. C foam 0. 3 % X 0) in 2012 - Second iteration of single Mimosa 26 embedded in kapton (CERNVIETTE) next week, full PLUME compatible ladder (six M 26) planned for beginning of the next year - CERNVIETTE process may by much less critical, if the last metal layer on the chip is used for better (less dense) “bonding pads” distribution 7 metal CIS 0. 18 µm process available! - Start to think about stitching exercise: wafer scale, up to 10 x 10 cm 2 monolithic sensor possible 21