Pixel Weekly

vidyo/phone meetings - Thursdays at 10:00 am (UK time)

Vidyo portal or Vidyo portal

In general, indico pages are listed in: https://indico.cern.ch/categoryDisplay.py?categId=547

Date Indico page Other notes/docs (e.g. uploads to PUUKA Twiki)
2016.06.16 https://indico.cern.ch/event/544157/ Meeting focussed on scoping new sensor design for RD53 (overview of recent previous designs given by Craig)
2016.06.09 https://indico.cern.ch/event/541129/  
2016.05.26 https://indico.cern.ch/event/536349/

Actions from last meeting:

1. PJD: Prepare irradiation programme to include irradiation of AC-coupled detectors, singles with and without zig-zag biasing, 200um thick sensors to be able to make “realistic” measurements. Contact Anna Macchiolo to discuss programme. Present at meeting on 26/5; Postponed to next meeting.

2. JL: To circulate mil-spec document for developing HASS for bump-bonding and other aspects of module construction.

3. CMB: To get Cr UBM wafers sent to Glasgow for I-V tests. DONE

4. JM: To check tested FE-I4 wafer stock and confirm if we have two tested wafers for module production as requested by RLB.

5. CMB: To order 10 CP6 and discuss with Micron when we have to define how many we want with UBM.

6. CMB/RLB/PJD: Meet and prepare plans for quads and singles for module construction, radiation programme and multi-module tests. Report at the next meeting; Postponed to next meeting

2016.05.12 https://indico.cern.ch/event/528140/  
2016.02.04 https://indico.cern.ch/event/493370/

1. Update on Pixel readout ,Andeas

2. Irradiation programme, Paul -discussion

3. Multi-module status, Ilya

4. Brief updates

1. Module production, Richard

2. Micron update, Craig

3. Itk week talks

5. AOB

2016.01.21 https://indico.cern.ch/event/486293/

1. Report on thinned modules and module production, Richard, 20mins

2. Module results, Ilya, 20mins

3. Status of hybrid production, Sneha, 10mins

4. Status of ASIC testing, John, 10mins 5. AOB

2015.11.12 https://indico.cern.ch/e/461536  
2015.10.15 https://indico.cern.ch/e/455163  
2015.10.01 https://indico.cern.ch/e/450601  
2015.09.03 http://indico.cern.ch/e/442908 .
2015.08.20 http://indico.cern.ch/e/440077


  1. Module assembly Ilya/Paul
  2. Hybrid production: Sneha
  3. Followup on encapsulation: Kirk
  4. Reliability workshop report part 2: Kirk
2015.08.06 https://indico.cern.ch/event/436949/


  1. Status of module production: Richard
  2. Report on module assembly: Paul/Ilya
  3. Discussion of flex and tape designs: Ilya/Sneha
  4. Review of parylene studies: Kirk
  5. Results of parylene studies: Paul
  6. Summary of Reliability & Risk workshop: Kirk
2015.07.09 https://indico.cern.ch/event/408121/


  1. Report on module assembly: Paul
  2. Status of module mini-production: Craig (20mins including discussion)
  3. AOB
2015.06.18 http://indico.cern.ch/e/403008  
2015.05.28 https://indico.cern.ch/event/397116/



  1. Module assembly of CMS Phase-I pixel upgrade: Kirk (20mins)
  2. Module mini-production: Craig (20mins including discussion)
  3. UK preparations for module assembly: Craig (30mins including discussion)
  4. Report on high rate bump bonding: Richard (20mins including discussion)

Items 3 & 4 will be reported at tomorrow's ITk module meeting. The indico page is at: https://indico.cern.ch/event/396129/

2015.05.07 https://indico.cern.ch/event/391195/
  1. Update on thinned module bump bonding, Richard 15mins
  2. Update on RAL BB, John L, 15mins
  3. Status of multimodule testing, Richard/Sneha, 15mins
  4. Hybrid to module assembly work, Ilya/Paul, 15mins
  5. AOCB
  1. Update on thinned module bump bonding, Richard Bates
    See Richard Slides.
    Richard presented an update on thinned module assembly. This focused on work at Advacam on flip chip of assembly. Several different techniques have been looked at: Au UBM to replace current Advacam transition metal UBM, solder on sensors to give a solder-solder bond and a new reflow method: "Advacam reflow method". 5 samples with 100um thick readout chips and 300um single chip sensors, some have SCL and some do not. Good bump yields with solder-solder and also Advacam reflow method.
    More samples being made.
    Need extend Advacam reflow method to quads and check it is compatible with large scale production.
    Samples will be subjected to thermal cycling but it was pointed out that glues had failed on strip samples at -50C. Test samples will be thermally cycled before the samples.
  2. Module production exercise
    See Richard slides (last slide)
    Richard reported that at the pixel design group large scale bump bonding was discussed (https://indico.cern.ch/event/392019/). The bump bonding capacity needs to be understood to support the case for increasing the pixel area to a 5th and 6th layer. The aim is to place orders with a number of vendors: IZM, Selex, Advacam/Cea-Leti, HPK and see if the meet required production rates and quality. It would be better to have more vendors, around 6 so that we have a choice rather than being limited to using the current 4.
    Daniella pointed out that RTI have worked on bump bonding for CMS and should be considered. Vitaliy Fadyev is the currently the contact for them. Daniella will contact Vitality regarding RTI.
    RAL have been considered as small site that could work on the inner layer given their limited resources. However, John reported that the following discussions, he had been given the go ahead to look at developing 300mm capability.
    We need to consider module production, hybrid assembly and final testing.
    The programme of bump bonding needs to be complete by end of the year so that decisions can be made on the layout. The aim from the UK is make and test 50 assemblies with CEA-Leti & Advacam, and also a similar number with RAL. Craig will organise a meeting with Craig, John L, Richard and Paul to discus the programme for this.
  3. Update on RAL BB, John Lipp
    See John's slides
    John gave an update on the studies to understand the quality of the bumps. In the "old" daisy chain samples that included Au in the UBM, intermetallics were observed, confirming that removing the Au from the UBM was correct. The results from the module that did not have Au in the UBM showed no evidence of intermetallics. The UBM and inter-bump interface appear to be good. The remaining possible problems are that the parallelism of the FE-I4 and sensor may not be good enough or there may have been Cr contamination from resputtering. If it is the resputtering, this has now been fixed. Next step is to make more modules and evaluate them.
  4. Multi-module testing, Kenny
    See Kenny' slides
    Kenny showed the progress with the multimodule testing system. After some teething problems with connections the system is now setup to test up to 16 chips = 4 quads. This will start with modules on PCBs but will move to testing modules with flex hybrids on the half disk. The serial powering system is up and runnning with SCTDAQ and an interlock system.
  5. Hybrid mounting, Paul
    2 quads ready for sending to Glasgow, will be sent up together with the assembly jigs.
    Glasgow will send 6 FR4 populated hybrids to Liverpool.
    Richard reported that hybrids from Flexible technologies had cracks. This appears to be due to using a flexible solder resist rather than polyamide.
    There was a brief discussion on using rice paper as a replacement for the gluing stencil. Ilya will be asked to report on this at the next meeting.
    Kirk mentioned his experience with using a rubber stamp method for glue dispensing. He will report on this at the next meeting .
  6. AOB
    Paul reported that Sussane and Wuppertal cofirmed that we will get 40 untested PPSP chips. This will be in August/September.

Paul Dervan noted: This was the glue/paint that failed at about ~40C: http://uk.rs-online.com/web/p/conductive-adhesives/1863593/

2015.04.16 https://indico.cern.ch/event/388245/
  1. Hybrid to module assembly and electrical testing of modules with flex hybrids: Ilya/Paul
  2. Report on In bump bonding at RAL: John Lipp
  3. Summary from DAQ meeting: Craig
  4. Input to RD53 sensor discussion: All
  5. AUW talks: All
2015.03.19 https://indico.cern.ch/event/382297/



  1. Module assembly and flex status: Paul/Ilya
  2. Multi-module test status: Richard
  3. Stuff: USBpix order, PPSP chip, PixelFest, DAQ meeting
  4. AoB

Can groups send Craig information on what USBPix systems you have and whether they are working or not. Andreas Korn is organising an order for new MIO3 and MMC3 cards.

2015.03.05 https://indico.cern.ch/event/368657/ 11:15am
2015.02.25 https://indico.cern.ch/e/373270 11:15am

UK WP1: Meeting Summary
Meeting Commenced: 11:20
Liverpool: P.Dervan, M. Milovanovic, I. Tsurin
Oxford: D. Bortoletto
Glasgow: K. Doonan
RAL: J. Matterson, I. Wilmut, J. Lipp
Manchester: J. Pater, G. Miller
Apologies: C. Buttar, C. Da Via, V O’Shea
1. Summary of the meeting:
• Mike, the Liverpool wire bonder has had an operation. He will be off work for three weeks. So there was no news on the sensors/module side of things.
• The assembly jig is nearly finished (see the slides from Ilya on the indico site). Quotes from three companies have just been received for the glue stencils. Would everything is ready we would like to have a review of the process and jig.
• Paul has been in touch with the German groups about the PSPP chip. They are making a new submission at the end of February. The UK would like some (including the strip
group). We will go and visit the German groups in the next month or so.
• If we redesign the hybrid with the PSPP chip the tapes and EOS card will need to be modified. Jo mentioned that an email had just been sent around about a face to face
meeting about the EOS card. The PSPP has now been included.

• Jo introduced Graham Miller. He is Manchester’s new electrical engineer.
• Jo mentioned the face to face EOS meeing. This will happen in early February. A doodle pole has been sent around.
• There will be a test beam at DESY around Easter time. The beam will be setup for 3D devices. Do you want to send the AC devices?

• A probe station has been ordered.
• The new lab will be ready around May time.
• Lots of work has been done on the CMOS sensors. These will be irradiated next Tuesday in Birmingham.

• Tape tests will happen soon.
• Kenny has been working on the reconstruction of test beam data for sensors with different geometries

• Wafer (ASIC) probing continues.
• More wafers are needed.
• Stages need to be ordered for the module mounting system
• Bump bonding of CP6 wafers is on going.
• The GDS file for the top metal is needed.
• Work on QUAD bump bonding is progressing.
• The modules with low bump yield are being investigated.
• A low deposition system is being looked at, to reduce the out-gassing.
• John Lipp requested that the next few meeting were announced in advance. To help with planning.
• There is a RCE/COB workshop in Oxford next week.
• The next few meeting will be at 11:15am on the 5th Feb, 19th Feb and 5th March.

13th Nov 2014
Modification key is wp1
 Vidyo pin: 54321
1. CP6 discussion: do we dice at Micron or get a new set of masks made? Paul
2. Module production update, Richard
3. Update on wafer testing, John M
4. Discussion of pixel fest agenda, all
If you want to add anything, please let me know.


Attending: C. Buttar, R. Bates, A. Stewart, J. Matheson, K. Wraight, K.

Sexton, J. Pater, R. Plackett, F. Munoz, I. Tsurin, M. Milovanovic

Indico page: https://indico.cern.ch/event/351594/

Richard Plackett from Oxford was welcomed to the meeting. Oxford are considering doing pixel module assembly during production.

1. Dicing at Micron

Richard B will contact Micron and the dicing company used by John Lipp about cost and time for dicing CP6, and send round an email.

2. Module production

First CP6 wafer has been bump-bonded.

CP6 Quads: 5 quads made up, two damaged during visual inspection. Reason was noted and will be avoided in future.

Distribution: 2 quads for irradiation --> Liverpool for bonding; 1 baseline in Glasgow.

Also want to identify 1 quad for thermal runaway measurements; Richard B has identified an assembled quad that can be used.

CP6 singles All singles made up (6). All I-Vs look ok, wafer 3009-8.

Richard B will update sharepoint.


3 to Liverpool for bonding & testing, 1 to go to Francesca in Manchester

3 at Glasgow for bonding & testing

2nd wafer has UBM and will be flipped at Advacam this week once Sami is back from NSS.

CP5 AC/DC sensors: all 12 good assemblies have been made. 4 at Glasgow and 8 at Liverpool.

Thinned modules: 1 wafer with SCL at Advacam. Some die have been returned to Cea/Leti for TDM measurements. Sami had done some flip-chipping trials. The die are very flat on the tool but after a tack bond and reflow he did not see good contact. These are preliminary results and Sami has more to do. Comments from Sami: worried that UBM is not sufficiently wettable and SAC solder may be an issue.

Another possibility to be considered is to use Cu as an SCL. This has been done by Medipix where they have used Cu as an redistribution layer and these devices have shown no change in bow with temperature.

3. Module assembly

Ilya has discussed getting the module assembly jig made in Liverpool workshop. It has been proposed that this is done by an apprentice. This has low priority and Paul needs to be negotiate with workshop management. Gluing studies are required. This can be done by a student and Ilya will discuss with Tim Jones. A stencil with 9 patterns will be ordered.

There will be a meeting at RAL to discuss module assembly.

Ilya will submit his new hybrid design to Quick Circuits and get 20 hybrids made and stuffed. MUX and PSP chip will be added as separate boards once they are available. A flex to RJ45 board is required. Ilya will send details to Richard B and Richard will get panasonic connectors from Liverpool.

4. Wafer testing

Glasgow is reprobing 0.25 of a wafer probed at RAL to confirm results.

Expect there will be 5 wafers probed between Glasgow & RAL by Christmas.

John and Andrew will produce a write up on the testing procedure and results.

RAL is reprobing a round-robin wafer from LBL. The green, yellow, red, blue yields broadly agree. John is investigating differences.

Craig will check FE-I4 stock and confirm what remains to be tested.

5. Agenda for Pixel Fest.

The outline agenda is at: https://indico.cern.ch/event/351038/

It will be discussed at the next meeting.

6. Testbeam studies (see slides on indico page) Francesca reported on results with 3D sensor at recent SPS testbeam. A strange pattern in the hit map was observed, see slide 9. It appears to be a region of low efficiency. No-one recognised this effect. Kenny will discuss with Francesca.

7. AC/DC sensor characterisation (see slides on indico page) Marko presented characterisation of the AC/DC sensors. He notices lower noise with the USBpix system, as he has seen before. AC devices have lower noise than DC devices. 90-Sr source scans indicate that the DC sensors have a slightly larger signal than AC sensors, ~6.4ToT vs 5.9ToT on plateau.

There was only a brief discussion due to lack of time this will be revisited at the next meeting.

Please send me comments and/or corrections by Monday 24/11. I send round corrected minutes and put them on the indico page.

29th Oct 2014  
Dear All,
Notes from WP1 meeting 29/10
Present: A. Stewart, J. Pater, P. Dervan, C. Buttar, K. Doonan, M. 
Craig discussed the proposal by Anna Macciholo regarding having a single 
talk on sensors and other areas in the module meeting. It was agreed 
that this was reasonable and that we should see if it works. Craig will 
Craig reported that there was concern expressed by 
Advacam regarding dicing of CP6 sensors due to the mistake in the mask design. As previously discussed, 
a plan had been sent to to Advacam that sacrificed single sensors. It 
had also been agreed to have a wafer diced at Micron to see if this 
could avoid sacrificing the single sensors and having an extended edge 
on one of the quads.
The question was raised as to whether we should get a new CP6 mask set 
that is better for dicing. It was agreed we should investigate dicing 
with Micron first.
 *Paul will discuss dicing at Micron with Ilya and Gian to check* 
 *availability and cost and report at the next meeting.* 
Craig reported that the he had discussed the probe marks on the chips 
shown in Marko's slides. He said it was unusual to probe a chip twice 
but this had been done from time to time as required. It had not been a 
problem during production. He could not make a comment on dicing.
It was agreed that new modules will undergo a visual inspection to look 
at the quality of dicing, probe marks, scratches and chips. A record 
will be kept for each module.
 *Advacam also have a visual inspection sheet and Richard will ask if they* 
 *can be sent to us along with a module.* 
Please send me comments and corrections.
Craig & Paul
16th Oct 2014 https://indico.cern.ch/event/346944/  
4th Sept 2014 https://indico.cern.ch/event/338885/  
28th August 2014 https://indico.cern.ch/event/337453/  
21st Aug 2014 https://indico.cern.ch/event/336375/  
14th August 2014 https://indico.cern.ch/event/335381/  
8th August 2014 https://indico.cern.ch/event/334347/  
17th July 2014 https://indico.cern.ch/event/331148/


1. Status of assembly jigs and procedure for mounting hybrids to modules, Ilya

2. Status of PA5 production and tests, Ilya/Marko

3. Cooling system for module testing, Richard

4. CP6 production status, Gian/Sergey

5. TB samples for October

6. AOB

3rd July 2014 https://indico.cern.ch/event/328484/  
19th June 2014 https://indico.cern.ch/event/325758/  
12th June 2014 https://indico.cern.ch/event/324540/  
5th Jun 2014 https://indico.cern.ch/event/323508/  
29th May 2014 https://indico.cern.ch/event/322180/  
22nd May 2014 https://indico.cern.ch/event/321067/  
15th May 2014 https://indico.cern.ch/event/319837/  
24th April 2014 https://indico.cern.ch/event/315694/


1. Brief reports

Status of Micron sensors CP6 production, Gian/Sergey Status of testbeam preparations, Kenny

2. Discussion on module parameters for FEA thermal simulations, All See attached note by Graham Beck

3. Update on source scans for slim edge sensors, Marko

4. Response to FE-IX talk at AUW, All

5. AoB

Modification key is wp1

Vidyo pin: 54321

3rd April 2014 https://indico.cern.ch/event/311651/  
27th Mar 2014 https://indico.cern.ch/event/310167/


  • Freiburg talks: The list i sent to Paolo after last weeks discussion can be found below.
  • TB analysis status and SLAC discussion
  • Status of RAL In-bumped module
  • Flex and tape status
  • Update on Cea-Leti production
  • AOB

List sent to Paolo after last weeks discussion

1. Sensors

Results from characterisation of quad sensors.

We got some nice data at DESY with unirradiated and also with an irradiated sensors.

Results from characterisation of pixel sensors with different geometries As for the quads, we have some nice data from the Feb DESY TB run with unirradiated and irradiated sensors.

2. Modules

Interconnect developments

This would cover work with Cea-Leti, we have first results on using the backside compensation, status of bump-bonding at Advacam.

Status of In bump bonding at RAL

This would cover an update on the In bump bonding at RAL. We have the first module from RAL and would hope to have results from characterising.

It may be this could be merged with the more general interconnect developments.

Depending on overlaps with the other meetings, we could contribute a summary of quad and different geometries in case as there may be people who do not see the talks in the sensor sessions.

Flex development

We have a prototype flex on thin FR4 and hope to have bonded chips to it and characterised it by Freiburg.

Wafer probing

We can provide an update on UK work in this area.

20th Mar 2014 https://indico.cern.ch/event/309001/  
13th Mar 2014 https://indico.cern.ch/event/307614/  
6th Mar 2014 https://indico.cern.ch/event/306413/  
27th Feb 2014 https://indico.cern.ch/event/304966/  
21st Feb 2014 https://indico.cern.ch/event/303568/


1. Testbeam preparation, Marko/Kate

Devices to be tested, test conditions and priorities

2. Status of wafer testing, John

30th Jan 2014 https://indico.cern.ch/conferenceDisplay.py?confId=298710  
23rd Jan 2014 https://indico.cern.ch/conferenceDisplay.py?confId=297209  
16th Jan 2014


28th Nov 2013 https://indico.cern.ch/conferenceDisplay.py?confId=283615  
31st Oct 2013 Indico page


Status of Quad and CP-V modules

  • Q5 at Glasgow: Craig
  • Characterisation of CP-V: Marko
  • Status of thin and AC coupled sensors from Micron: Dean

Testbeam preparations

  • People & safety training
  • RCE system
  • PS and other components

Status of wafer probing at Edinburgh: Corrinne

Update on RAL bump-bonding: John

24th Oct 2013 Indico page  
17th Oct 2013

Indico page

Weekly 171013&FolderCTID=0x0120002E98033CFF626142BE1899F87D8B6F28&View={8C524712-F3D0-4480-B753-D977C03D97EA}&InitialTabId=Ribbon.Document&VisibilityContext=WSSTabPersistence

10th Oct 2013 Indico page  
3rd Oct 2013 confId=276089  
26th Sept 2013 https://indico.cern.ch/conferenceDisplay.py?confId=275058">confId=275058  
12th Sept 2013 confId=268648  
5th Sept 2013 confId=271197  
29th Aug 2013 confId=270174  
22nd Aug 2013 confId=264982  
8th Aug 2013 confId=266895  
1st Aug 2013 confId=266005 Notes: https://indico.cern.ch/getFile.py/access?resId=0&materialId=slides&confId=266005
25th July 2013 confId=264982 Notes: https://indico.cern.ch/getFile.py/access?resId=0&materialId=1&confId=264982
30th May 2013  


Pre_and_post_assembly_IVs_summary (Tom Mcmullen)

Status DAQ (Andreas Korn)

4th Oct 2012   September CERN Testbeam Update CERN-PPStestbeam-Overview-sept2012.pptx
9th Aug 2012   Discussion document on Flex PCB:-
15th Mar 2012   Glasgow Update: GlasgowUpdate_150312.pdf
29th Jan 2012   Minutes: 2012-01-19_UKModules.txt
10th Nov 2011    
3rd Nov 2011   Micron Quad Detectors IV: 031111.pptx
9th June 2011   Minutes
2nd June 2011   Minutes
19th May 2011   Minutes
5th May 2011  
21st Apr 2011    
7th Apr 2011   Minutes of the meeting Minutes_from_April_7th_UK_Pixel_Module_phone_meeting.doc
3rd Mar 2011   -- RichardBates - 2011-01-21

-- CraigButtar - 2013-06-03

Topic attachments
I Attachment History Action Size Date Who Comment
Microsoft Word filedocx Notes_from_WP1_meeting_30th_May.docx r1 manage 117.2 K 2013-06-03 - 14:57 CraigButtar  
PDFpdf PixelDAQ_300513.pdf r1 manage 15560.6 K 2013-06-03 - 14:58 CraigButtar  
PowerPointpptx Pre_and_post_assembly_IVs_summary.pptx r1 manage 853.5 K 2013-06-03 - 14:58 CraigButtar  
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