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Leakage Monitoring and Controlwith an Advanced e-beamInspection SystemHermes Liu, J H Yeh, Chan Lon Yang, S C Lei,J Y Kao, Y D Yang, Mingsheng Tsai, S F TzouUnited Microelectronics Corp.Hong Xiao and Jack JauHermes Microvision, Inc. USA,
List of Topics Introductionto EBI Principle of detection Experiment arrangement Experiment results Conclusions
Illustration of eScan 300Primary BeamSecondary andBack ScatteredElectrons
Positive ModeSecondary Electron andBack Scattered ElectronSecondaryElectronBack Scattered ElectronLE (eV)
W-Plugs & VC in Positive ModeDarkBrightBrightBrightBrightNormalPolyN N PThis studyeNBrightP eP NBrighteBrightePolyGate ects)N PeN NeP NeP PeeGate Oxide
Experiment 1 6wafers 3 ion implantation conditions After WCMP Onewafer from each condition send toinspection Another one continue to M1 for WAT Inspectedand measured test keys andSRAM arrays
Correlation of WAT and eScan Leakage CurrentSplit 1Split 2 Split 3BVC DefectBVC Defect Count
Correlation of WAT and eScan Defect countSplit 1Split 1Split 2Split 3Split 2Split 3
GLV Binning Strongleakage causes high GLV Auto binning GLV of all BVC defects High GLV BVC map matches with highleakage current map very well.
WAT Leakage Map and eScan BVC MapGLV1GLV3GLV2Bin 1GLV4
Extrusion Length vs eScan GLVExtrusion lengthGL vs NISI piping extruded length60504030L1L3L4GLV2GLV1L220100GLV4GLV3
NiSi DiffusionSEMTEMLeakage is caused by NiSi diffusion
Experiment 2 13wafers 3 ion implantation conditions eScan inspection on two test keys WAT after M1 CMP
Testkey 1Leakage currentBVC counts vs. WAT LeakageWATTestkey 2Leakage currentTest key 1 BVC Counts2R 0.7464Test key 2 BVC Counts2R 0.8079BVC counts
Conclusion BVCdefects of W-plugs that connect toNiSi on N /P-well junction on both test keystructures and SRAM array BVC defect counts correlate with WATleakage current on both test key and SRAM FA delayer showed that N /P-well leakageis caused by nickel silicide diffusion Extrusion length of the nickel silicidestrongly correlates with GLV of the W-plug BVC counts strongly correlate to WATleakage current
Development More EBI systems: Leap Scan EBI : eScan 310, eScan 315 (Improveresolution)Continue scan EBI : eScan Lite (Improve throughput)Hotspot EBI: eP2More EBI applications Monitoring hole non-open at contact AEI and WCMP.Qualifying the contact lithography process window.Negative ModeTM EBI for P /N-well leakage detection.Monitoring NMOS and gate leakage right after NiSiformation.
Hermes Microvision, Inc. USA, List of Topics Introduction to EBI Principle of detection Experiment arrangement Experiment results Conclusions. Primary Beam Secondary and Back Scattered Electrons Illustration of eScan 300. LE (eV) Back Scattered Electron Secondary Electron Secondary Electron and Back Scattered Electron Positive Mode.
