1. Wojciech.Dulinski@ires.in2p3.fr STAR Microvertex Upgrade Meeting, Strasbourg, April 2008 1 Status of sensors from the engineering run AMS-035 OPTO Wojciech Dulinski on behalf of IPHC Outline  Engineering run AMS-035 OPTO  Wafer delivery story  Present status of discussion with AMS and possible solutions

2. Wojciech.Dulinski@ires.in2p3.fr STAR Microvertex Upgrade Meeting, Strasbourg, April 2008 2 Layout of the reticle of the engineering run AMS-035 OPTO 07/2006 on 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…

3. Wojciech.Dulinski@ires.in2p3.fr STAR Microvertex Upgrade Meeting, Strasbourg, April 2008 3 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”

4. Wojciech.Dulinski@ires.in2p3.fr STAR Microvertex Upgrade Meeting, Strasbourg, April 2008 4 General remarks concerning tested wafers -Dark current on rad-tol diodes (MimoSTAR, MimoTEL) is factor of 5 to 10 higher than expected (from M15 and M*2) - Dark current on non rad-tol diodes (Mimosa18) is factor of 5 to 10 lower than expected… - Excellent yield of medium-size sensors (except for two 14 µm MimoTELs), this is NOT the case of MimoSTAR3… - Excellent noise performance of M18: ENC ~10 electrons at room temperature and 4 ms integration (10 MHz clock)

5. Wojciech.Dulinski@ires.in2p3.fr STAR Microvertex Upgrade Meeting, Strasbourg, April 2008 5 More remarks concerning yield of MimoSTAR3 and MimoTEL - Poor yield of MimoSTAR3 from 2006 run, acceptable yield of MimoTEL (>80%) - Even worse yield of MimoSTAR3 from 2007 run, catastrophic yield of MimoTEL (~0%, based on 3 thinned and 3 non-thinned samples) - Still excellent yield of M18 (also after thinning)… - Start of investigation, anti-correlation between broken pixels and the total dark current, Vias suspected… - FIB at AMS, no conclusion (wrong conclusion), break-through study at BNL!

6. Wojciech.Dulinski@ires.in2p3.fr STAR Microvertex Upgrade Meeting, Strasbourg, April 2008 6 Discussion with AMS - Finally, AMS admitted the process flaw - A lot of time spend in order to find a good solution - It seems to converge now…

7. Wojciech.Dulinski@ires.in2p3.fr STAR Microvertex Upgrade Meeting, Strasbourg, April 2008 7 Discussion with AMS and their recommendation (status from April 2 nd, 2008) (April 3) 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 from the experiments they performed over the last weeks we feel very confident to reach a much better yield now. Fabrication time for new Wafers with the existing mask set would be approximately 4-5 weeks, the generation of new masks would take 2-3 days in addition. (March14) >> We are currently running some "shortloop wafers" which means that we are >> mainly processing metallization and interconnects to find possible root >> causes. Although the results are not 100% fixed we found an etching >> equipment that is not that sensitive, anyway we have to adjust some >> process steps for you structures. >> In addition we defined to start additional wafers with the next >> engineering run where we will perform FIB inline cuts to be able to >> control the via contact etching. >> 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 >> "stripe-form" will behave much better at CMP(Chemical Mechanical >> Polishing). >> Thank you for your patience. >> >> Best Regards, >> Sigurd >>________________________________________________________________________ >> >> Sigurd Hellinger >> Senior Customer Engineer Full Service Foundry

8. Wojciech.Dulinski@ires.in2p3.fr STAR Microvertex Upgrade Meeting, Strasbourg, April 2008 8 Several Mimosa18 successfully bonded to PCB

9. Wojciech.Dulinski@ires.in2p3.fr STAR Microvertex Upgrade Meeting, Strasbourg, April 2008 9 Conclusions - We converge for a fast re-processing of the engineering run, with minimum of changes on the masks (Active, Metal1, Poly???) - Some (financial) details still to be discussed with, but modification can be implemented still this week …

10. Wojciech.Dulinski@ires.in2p3.fr STAR Microvertex Upgrade Meeting, Strasbourg, April 2008 10 Reminder of layout to be modified… MimoSTAR3 pixelMimosa18 3x3 pixel cluster (the same area as M*3 single pixel)