Difference: PixelWeekly (1 vs. 42)

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

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

Modification key is wp1

 Vidyo pin: 54321

Agenda

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.

Distribution

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.

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

Agenda

1. Report on module assembly: Paul
2. Status of module mini-production: Craig (20mins including discussion)
3. AOB

Agenda

1. Report on module assembly: Paul
2. Status of module mini-production: Craig (20mins including discussion)
3. AOB

11:15-13:00

Agenda

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/

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/

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/

Dear All,

Notes from WP1 meeting 29/10

Present: A. Stewart, J. Pater, P. Dervan, C. Buttar, K. Doonan, M. 

Milovanovic

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 

reply.

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

Agenda

1. Testbeam preparation, Marko/Kate

Devices to be tested, test conditions and priorities

2. Status of wafer testing, John

Agenda:

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

Agenda:

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

Agenda:

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

Agenda:

• 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.

Notes_from_WP1_meeting_30th_May

Pre_and_post_assembly_IVs_summary (Tom Mcmullen)

Status DAQ (Andreas Korn)

Indico page

Agenda

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