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STAR Microvertex Upgrade Meeting, Strasbourg, April 2008
Status of sensors from the engineering runAMS-035 OPTO
Wojciech Dulinski on behalf of IPHCWojciech Dulinski on behalf of IPHC
Outline Engineering run AMS-035 OPTO Wafer delivery story Present status of discussion with AMS and possible solutions
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STAR Microvertex Upgrade Meeting, Strasbourg, April 2008
MimoStar3
MimoTEL Imager10µ Imager12µ
Mimosa16 Mimosa16
Latchup ADC ADC MyMap
TestStruct
Layout of the reticle of the engineering run AMS-035 OPTO 07/2006 Layout of the reticle of the engineering run AMS-035 OPTO 07/2006 on 14 µm (standard) and 20 µm epi substrateon 14 µm (standard) and 20 µm epi substrate
Several devices of direct interest for EUDET: MimoTEL (256x256, 30 µm pitch), HRTracker (512x512, 10 µm pitch), Mimosa16 (binary readout prototype), MimoSTAR3L, ADC, test structures…
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STAR Microvertex Upgrade Meeting, Strasbourg, April 2008
• End of October 2006, reception of engineering run• Two wafers diced (one 20 and one 14 µm), beginning of tests• Problem: missing layer (poly HighRes)• February 2007: re-processing• One wafer from this run submitted for thinning (down to 50 µm,
on reticle basis) at the high-tech company at California (via LBL)
• Purchase of remaining (4+5) wafers and beginning of probe-testing (yield study). Currently still under way (MimoSTAR3)
““Wafer delivery story”Wafer delivery story”
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STAR Microvertex Upgrade Meeting, Strasbourg, April 2008
General remarks concerning tested wafersGeneral remarks concerning tested wafers
-Dark current on rad-tol diodes (MimoSTAR, MimoTEL) is Dark current on rad-tol diodes (MimoSTAR, MimoTEL) is factor of 5 to 10 factor of 5 to 10 higherhigher than expected (from M15 and M*2) than expected (from M15 and M*2)
- Dark current on non rad-tol diodes (Mimosa18) is factor of 5 to - Dark current on non rad-tol diodes (Mimosa18) is factor of 5 to 10 10 lowerlower than expected… than expected…
- Excellent yield of medium-size sensors (except for two 14 µm - Excellent yield of medium-size sensors (except for two 14 µm MimoTELs), this is NOT the case of MimoSTAR3…MimoTELs), this is NOT the case of MimoSTAR3…
- Excellent noise performance of M18: ENC ~10 electrons at - Excellent noise performance of M18: ENC ~10 electrons at room temperature and 4 ms integration (10 MHz clock)room temperature and 4 ms integration (10 MHz clock)
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STAR Microvertex Upgrade Meeting, Strasbourg, April 2008
More remarks concerning yield of MimoSTAR3 and More remarks concerning yield of MimoSTAR3 and MimoTELMimoTEL
- Poor yield of MimoSTAR3 from 2006 run, acceptable yield of Poor yield of MimoSTAR3 from 2006 run, acceptable yield of MimoTEL (>80%)MimoTEL (>80%)
- Even worse yield of MimoSTAR3 from 2007 run, catastrophic - Even worse yield of MimoSTAR3 from 2007 run, catastrophic yield of MimoTEL (~0%, based on 3 thinned and 3 non-thinned yield of MimoTEL (~0%, based on 3 thinned and 3 non-thinned
samples) samples)
- Still excellent yield of M18 (also after thinning)…- Still excellent yield of M18 (also after thinning)…
- Start of investigation, anti-correlation between broken pixels - Start of investigation, anti-correlation between broken pixels and the total dark current, Vias suspected…and the total dark current, Vias suspected…
- FIB at AMS, no conclusion (wrong conclusion), break-through - FIB at AMS, no conclusion (wrong conclusion), break-through study at BNL!study at BNL!
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STAR Microvertex Upgrade Meeting, Strasbourg, April 2008
Discussion with AMSDiscussion with AMS
- Finally, AMS admitted the process flaw Finally, AMS admitted the process flaw
- A lot of time spend in order to find a good solution- A lot of time spend in order to find a good solution
- It seems to converge now…- It seems to converge now…
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STAR Microvertex Upgrade Meeting, Strasbourg, April 2008
Discussion with AMS and their recommendation (status from Discussion with AMS and their recommendation (status from April 2April 2ndnd, 2008), 2008)
(April 3)(April 3)First of all I have to point out that we don't have any wafers currently First of all I have to point out that we don't have any wafers currently
in our FAB. I had a discussion with our process engineers yesterday and in our FAB. I had a discussion with our process engineers yesterday and from the experiments they performed over the last weeks we feel very from the experiments they performed over the last weeks we feel very confident to reach a much better yield now. Fabrication time for new confident to reach a much better yield now. Fabrication time for new
Wafers with the existing mask set would be approximately 4-5 weeks, theWafers with the existing mask set would be approximately 4-5 weeks, thegeneration of new masks would take 2-3 days in addition.generation of new masks would take 2-3 days in addition.
(March14)(March14)>> We are currently running some "shortloop wafers" which means that we are>> We are currently running some "shortloop wafers" which means that we are
>> mainly processing metallization and interconnects to find possible root>> mainly processing metallization and interconnects to find possible root>> causes. Although the results are not 100% fixed we found an etching >> causes. Although the results are not 100% fixed we found an etching >> equipment that is not that sensitive, anyway we have to adjust some >> equipment that is not that sensitive, anyway we have to adjust some
>> process steps for you structures.>> process steps for you structures.>> In addition we defined to start additional wafers with the next >> In addition we defined to start additional wafers with the next
>> engineering run where we will perform FIB inline cuts to be able to >> engineering run where we will perform FIB inline cuts to be able to >> control the via contact etching.>> control the via contact etching.
>> As already mentioned in one of my prevoius emails please try to reduce>> As already mentioned in one of my prevoius emails please try to reduce>> the active area as well as metal1 density. We assume that metal1 in >> the active area as well as metal1 density. We assume that metal1 in
>> "stripe-form" will behave much better at CMP(Chemical Mechanical >> "stripe-form" will behave much better at CMP(Chemical Mechanical >> Polishing).>> Polishing).
>> Thank you for your patience.>> Thank you for your patience.>>>>
>> Best Regards,>> Best Regards,>> Sigurd>> Sigurd
>>________________________________________________________________________ >>________________________________________________________________________ >>>>
>> Sigurd Hellinger>> Sigurd Hellinger>> Senior Customer Engineer Full Service Foundry>> Senior Customer Engineer Full Service Foundry
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STAR Microvertex Upgrade Meeting, Strasbourg, April 2008
Several Mimosa18 successfully bonded to PCBSeveral Mimosa18 successfully bonded to PCB
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STAR Microvertex Upgrade Meeting, Strasbourg, April 2008
ConclusionsConclusions
- We converge for a fast re-processing of the engineering run, with We converge for a fast re-processing of the engineering run, with minimum of changes on the masks (minimum of changes on the masks (Active, Metal1Active, Metal1, Poly???), Poly???)
- Some (financial) details still to be discussed with, but - Some (financial) details still to be discussed with, but modification can be implemented still this week modification can be implemented still this week
……
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STAR Microvertex Upgrade Meeting, Strasbourg, April 2008
Reminder of layout to be modified…Reminder of layout to be modified…
MimoSTAR3 pixel Mimosa18 3x3 pixel cluster (the same area as M*3 single pixel)
