CMS Module Testing Issues Perspective from a large scale production project Anthony Affolder (for the UCSB module testing group) PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder Talk Overview Review current CMS testing procedures Assorted observations from limited testing experience on CMS components Outline UCSB module testing program Personnel, equipment, and infrastructure PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder CMS Testing Overview Review current CMS testing procedures Ensure understanding of testing prior to arrival at FNAL/UCSB Reproduction of hybrid tests on arrival Make sure any systematic failures in production techniques/materials found as early as possible M800 pre-production first chance to produce large quantities (>20) of single type of modules Need to be able to track time development of faults Answer open questions before full scale production Need of burn-in of hybrid/optical systems components Finalization of production procedure Finalization of testing procedure Both fault finding and module qualification PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Tests Prior to Arrival at FNAL/UCSB APV Chip Testing (1 minute) Voltage stressing (6 sec) Basic Functionality Pedestal Calibration Injection (2 MIP) Pipeline FHIT-Industrial Testing (1 minute) Connectivity Noise Strasbourg ????? CERN-Pitch adaptor bonding (20 minutes) Basic functionality Pedestal Noise Calibration Injection (2 MIP) Capacitive pulsing pitch adaptor Thermal cycle to –20 C Repeat test Warm to room temperature PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder Testing Concerns Hybrids tested only ~1-20 minutes Concern about infant mortality problems Hybrids not completely characterized Calibration circuit only tested at one injection point Pipeline pedestal/noise not thoroughly measured Requirements not consistent between sites Pedestal cuts changes between test stands On-chip common mode subtraction “feature” makes noise characteristics of open/saturated channels unpredictable We are attending CMS tracking week to address issues Motivate requirements on fault finding/performance issues Continuation of bringing CDF/D0 production experience to CMS PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Test System Grounding Issues PC, DAQ/ARC, LV supplies, and HV supply share common ground Leads to less than predictable results Suggest that a common-mode noise standard made With on-chip common mode subtraction removed (inverter off) Allows for more uniform testing results PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Lower Noise Requirements Improving grounding until common mode noise less than ~0.5 ADC in peak mode/ inverter off allows the use of raw noise as a powerful tool for finding opens, including the location Sensor-Sensor Pitch Adaptor-Sensor APV-Pitch Adaptor (???) Seen by Charge Injection TOB Module 83 Sensor-Sensor Open Visible PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Upper Noise Requirements High noise only affects signal efficiency (clustering) Use physics (radioactive sources/collision data) to determine cut value Expect values to be different for different systems SVX PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder Gain Measurement TOB Module 83 Multi-point gain measurements have many advantages More stable More uniformity between chips Tighter Cuts Gain Scan (0.5-3.0 MIP) (2 MIP injected)/2 TOB Hybrid Shows non-linearities Shows non-uniformities within chip PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder Noise Chip Edge Wings Increase in noise at chip edges But only in a few pipeline cells pipeline scan=latency scan Deadtimeless effect!! Fairly easy to reduce/avoid PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

UCSB Short-term Testing Plan Characterize hybrid (+PA) on arrival Basic functionality, gain scan, and deep test (ARC) Re-characterize module on completion of construction Basic functionality, gain scan, deep test, and IV curves (ARC) Vienna cold box test fraction of modules (DAQ) Acts as ~24 hour module burn-in Identifies mechanical/bond/electrical weaknesses prior to production of large number of modules Reduces reworking of rod/retrofitting of modules Rod assembly/characterization/burn-in (when parts and test setups available) PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Testing personnel at UCSB Professors Joe Incandela Claudio Campagnari David Stuart Post-docs Anthony Affolder Patrick Gartung (UC-Riverside) Graduate Students Steve Levy Shawn Stromburg +1-2 starting this summer Electrical Engineering Support Sam Burke ESE Master Student Anuroop Gupta (Database/programming) + Assorted Undergraduates and Techs (during full production) PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Current UCSB Testing Setup 1 ARC Controller + 1 ARC FE LV & HV Power Supplies Dry Air Clamshell Clamshell(UCSB) Plastic stand-offs 2 Locating Pins Kapton Extension Cables(UCSB) Easy connection/disconnection Solid mounting of DAQ equipment PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder Testing Facilities Clean Room (5th floor Physics) Adjacent to production area Module tests Fault finding and deep tests Module burn-in station Visual inspection table High Bay (Ground floor) Rod assembly/burn-in Convenient access to loading dock PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder Safety Protocols LV OVP,OCP HV Crowbar Protection Electrostatic Protection Ground mats on tables and floors Heel straps Combo tester at clean room entrance Touch tester at each station (Artist Rendition) PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder Testing Conclusions Slight modification of testing program would lead to more uniform and consistent fault finding between different sites/systems Reduce rework performed on completed rods Location of opens can be identified by combination of noise and internal calibration measurements Useful for rod burn-in fault finding Increase in noise at chip edges likely deadtimeless effect We are willing to study more thoroughly We have the manpower and the experience necessary to aid in development of the testing program while performing module quality assurance measurements PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Possible Rod Burn-in Issues LED systems may be necessary for discovery of “high current” pinholes and location of opens In current rod burn-in plan, no LED systems available Would necessitate new techniques to locate “high current” pinholes and opens New sensor qualification tests, backplane pulsing, lower common mode noise, etc. Burn-in at module stage provides important information on this issue LED tests still available Until rod components arrive this is not an issue PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Example of DAQ/ARC Differences PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

On-chip common mode subtraction Inverters share common point Current flows between channels Regular channel noise: s2sraw2-scm2 Opens/saturated channel noise: s2sraw2+scm2 Depending on scm, open channel have higher/lower noise PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Deadtimeless Scan (ISL) Issue two triggers with varying time separation Pattern of commands should include complete set of commands, measurements, resets, etc. Measure pedestal and noise at each unit of trigger separation With ISL, every command, chip change of state, and data readout caused pedestal shifts Would guess similar effect causing wing May also be related to PC controller Removed with DPS at CDF (Time Between Triggers) PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Calibration Injection Test Enhance pulse shape information with gain measurement Measure pulse heights at 6-13 calibration injection setting between 0-3 MIPs using internal calibration and fit Require gain between Glow and Ghigh Gain uniformity specification??? Require c2<c2cut (c2 based on noise measurement and knowledge of calibration circuit) Finds non-linear charge response and gain non-uniformities within chip Relatively simple to include in ARC software Only moderately increases testing time Calibration is fairly sensitive to environment/grounding PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Test System Grounding Issues (1) Module Testing Final PS System Sensor Sensor Hybrid Hybrid HV HV ARC FE +HV +HV HVGND 1.25V 2.5V GROUND LOOPS!!! Interconnect Bus Patch Panel/ LV ARC Controller -5V LV GND +1.25V -5V +2.5V GROUND LOOPS!!! AOH PC Optical Cables DOH Command And Data Cable PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CDF Module Burn-in Experience Significant number of pinholes created during burn-in (even after 5 hours running) L1- 0.166% of strips L3- 0.052% of strips L4- 0.033% of strips ISL-0.0071% of strips 7 additional pinholes created during data-taken L7 burnt-in at depletion voltage All others burnt-in with over-voltage Early module burn-in in CMS will indicate pinhole creation rate and effect on rod rework rate PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder Noise Measurements Lower noise requirements optimized to detect faults in production Very loose low noise requirement at hybrid level Noise only changes from ~0.6~0.4 for completely dead pre-amplifier 20% requirement will fail good channels Hybrid at UCSB tests better with shaper current set to zero Tighter low noise requirements at module/rod level Can identify open types/location Sensor-Sensor:~1.2 ADC PA-Sensor: ~0.7 ADC Chip-PA:~0.5 ADC Upper Noise requirement set by effect on signal efficiency Noise sets channel’s thresholds in clustering Effect is module type dependent Larger signal and wide pitch minimizes effect on noise on TOB Determine by source/cosmic testing PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Pedestal Tests (Current) Wafer Probing Average Pedestal: 67.1 50 <P < 90 ADC Cut FHIT (Industrial Tester) Average Pedestal:~90 ±20% Cut:~72<P<108 ARC Average Pedestal:~110 ±20% Cut:~88<P<132 DAQ Average Pedestal:~170 ±20% Cut:~146<P<194 Pedestal Requirement vary by as much as 70% Try to develop common test based on detector performance Different requirements for different sub-detectors PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

Hybrid Gain Measurement(1) 0-3 MIPs 0.5-3 MIPs Hybrid Tests on steel plate Large pickup effects cause large c2 when 0 MIP point included c2 fairly good when excluding zero Noise of calibration circuit not yet included PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder LED Pinhole Tests Voltage conversion assumes old resistor values in bias return circuit (22KW,100W) New Leakage Current (mA) Necessary With New Resistor Values Bias Ring Voltage m (Torsten Franke) With new resistor values (2.2KW, 681W): need ~120 mA for regular pinholes need >300 mA for “high current” pinholes May cause damage to sensors!!! PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder Gain Measurements (2) Zero point offset Low gain High gain PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder LED Pinhole Test LED pinhole test characteristics will change with bias return line modification Resistance on hybrid (22kW,100W)(2.2kW,683W) R(22 kO) PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder Test model(1) Add hybrid qualification prior to pitch adaptor bonding Thorough understanding of hybrids by adding more pipeline and gain measurements Make requirements/calculation algorithms consistent through testing process Wafer Probing FHITStrasburg Pitch Adaptor Bonding Module Construction Rod Construction/burn-in Allows for the reproduction of bad channel lists Eases tracking of fault creation Motivate requirements for fault finding and on silicon tracker performance Noise Occupancy Signal Efficiency Signal Resolution PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder

CMS Module Testing Issues-Anthony Affolder Test model(2) Improve system’s noise in order to use as powerful tool Identification of location of opens Modify deep tests Suggest different bad channel cuts specific to component type tested Remove all percentage requirements (relative to average) Replace with fixed requirements Use cooling box as module burn-in until shown unnecessary Reduces reworking during rod assembly Adds important information about necessity of LED tests for the finding of some pinholes and opens locations Demonstrates if hybrid burn-in necessary PMG Jan. 24 2002 CMS Module Testing Issues-Anthony Affolder