Difference: PixelWeekly (31 vs. 32)

Revision 322015-07-08 - JohnLipp

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META TOPICPARENT name="Meetings__Wikis"

Pixel Weekly

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28th May 2015 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/

7th May 2015 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/

16th April 2015 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
19th March 2015 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.

5th Mar 2015 https://indico.cern.ch/event/368657/ 11:15am
25th Feb 2015 https://indico.cern.ch/e/373270 11:15am
22nd Jan 2015  

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.

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