23 rd asemep national technical symposium manufacturing and r&d : leveling up the philippines...
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23rd ASEMEP National Technical Symposium
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
ESD Failure Analysis, Detection, and Simulation
Ray Nicanor M. Tag-atiNARTE: ESD-00480-NE
HGST Phil. Corp, a Western Digital Company
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
2. Process Benchmarking
Systematic Approach in ESD Auditing
3. ESD Assessment
4. Perform Measurements
5. Modeling and Simulation
6. ESD Control Conceptualization
1. Failure Mode Identification
Course Outline
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
2. Process Benchmarking
Systematic Approach in ESD Auditing
3. ESD Assessment
4. Perform Measurements
5. Modeling and Simulation
6. ESD Control Conceptualization
1. Failure Mode Identification
Course Outline
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Product Failure Analysis and Characterization
The severity of the failure will somehow provide some clues as to the source/s of ESD or EOS.
This will confirm if indeed the failure is due to ESD or EOS, and not mechanical , contamination, or other defects.
1. Failure Mode Identification
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Electrical Overstress (EOS) and ESD have almost the same failure mechanism but differs on the sources.
ESD Static or Transient
Sources:
The very fast (nano/picoseconds) ESD pulses. Low energy Often very small physical damage signatures
1. Failure Mode Identification
Product Failure Analysis and Characterization
ESD or EOS?
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
ESD Damage
Direct ESD HBM, MM, and CDM
Semiconductors (CMOS Capacitor) Magnetic Heads
(GMR/TMR)
• Severity of damage depends on the source of ESD.
• Direct ESD happens when there’s a discharge path.
ESD or EOS?
Product Failure Analysis and Characterization
1. Failure Mode Identification
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
ESD Damage
ESD from Within Field Induced Model (FIM)
• ESD happens within the device itself by mere exposure to the electrostatic field.
Good
Damaged Damaged
Magnetic Heads (TMR)
ESD or EOS?
Product Failure Analysis and Characterization
1. Failure Mode Identification
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
A device is electrically stressed over it’s specified limits in terms of voltage, current, and/or power/energy.
EOS failure is the result of "long" duration stress events (millisecond duration or longer).
EOS Dynamic or Continuous
ESD or EOS?
Product Failure Analysis and Characterization
1. Failure Mode Identification
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
EOS Damage
EOS damage is often the result of the high temperatures experienced during the EOS event.
External
• Visible bulge in mold compound• Physical hole in mold compound• Burnt/discolored mold compound• Cracked package
ESD or EOS?
Product Failure Analysis and Characterization
1. Failure Mode Identification
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
EOS Damage
Internal
• Melted or burnt metal• Carbonized mold compound• Signs of heat damage to metal lines• Melted or vaporized bond wires
Melted TMR
ESD or EOS?
Product Failure Analysis and Characterization
1. Failure Mode Identification
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Indications of EOS
• Failure signature from excessive load dump.
Transistor failure of the emitter Transistor failure of the emitter region of the dieregion of the die
Fused wire bond.Fused wire bond. Metallization run on Op-Metallization run on Op-Amp ICAmp IC
*images courtesy of www.semlab.com
ESD or EOS?
Product Failure Analysis and Characterization
1. Failure Mode Identification
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
• Failure signature from repetitive thermal cycling combined with high current.
Severely degradedSeverely degradedrecrystalized metal recrystalized metal (≥400(≥400ºC) ºC)
Indications of EOS
ESD or EOS?
Product Failure Analysis and Characterization
1. Failure Mode Identification
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Possible Causes of EOS
Uncontrolled voltage surge on the power supply or testers.
Voltage spikes due to internal PCB switching.
Voltage spikes due to an external connection –capacitive charge on an external cable, antenna pick-up of external switching noise, inductive loads.
Poor grounding resulting in excessive noise on the ground plane.
Overshoot or undershoot during IO switching.
EMI (electromagnetic interference) due to poor shielding in an electrically noisy environment.
ESD or EOS?
Product Failure Analysis and Characterization
1. Failure Mode Identification
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Distinguishing between ESD and EOS failures has always been of interest to failure analysts.
Since ESD and EOS failure attributes depends on the following:• nature of the electrical stress• circuit design• die lay-out, and • fab process used
It would be difficult (if not impossible) to come up with a catch-all manual to distinguish between EOS and ESD failures.
Summary
ESD or EOS?
Product Failure Analysis and Characterization
1. Failure Mode Identification
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
2. Process Benchmarking
Systematic Approach in ESD Auditing
3. ESD Assessment
4. Perform Measurements
5. Modeling and Simulation
6. ESD Control Conceptualization
1. Failure Mode Identification
Course Outline
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Process Mapping/Traceability
This will help in narrowing down the area to be audited.
Highlighted are the ESD-potential processes or tools.
2. Process Benchmarking
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
What to Look For in an Identified Process?
High-powered tools motors, transformers and HV power supplies, etc.High-powered tools motors, transformers and HV power supplies, etc.
Tools with pneumatics/mechanical movement or AC switching source of EMI.Tools with pneumatics/mechanical movement or AC switching source of EMI.
Tools with direct metal contact or probing to the ESDS.Tools with direct metal contact or probing to the ESDS.
Process Mapping/Traceability
2. Process Benchmarking
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Whole Line/Fab ESD Partition Assessment
Processes are being divided into different segments. ESD parametric testing is being done after each segment. Done to identify which process/es causes ESD failures.
Process Partition Experiment
2. Process Benchmarking
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
New Tool/Process Split ESD Parametric Analysis
ESD parametric test is done initially for the samples. This will serve as the baseline data.
Samples are then split into equal parts. Experiment is then performed.
ESD parametric test is then conducted and compared to the baseline data.
Process Partition Experiment
2. Process Benchmarking
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
2. Process Benchmarking
Systematic Approach in ESD Auditing
3. ESD Assessment
4. Perform Measurements
5. Modeling and Simulation
6. ESD Control Conceptualization
1. Failure Mode Identification
Course Outline
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Assess what are the ESD events that the identified process might contribute.
Note: This model is applicable to automated lines with less direct handling to ESD-sensitive devices.
High
Low
Probability of Occurrence
3. ESD Assessment
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Recommended Measurements
ESD EventsMeasurements
Category Parameters Method
Machine Model (MM)
Static:- Non-powered Tools- Powered Tools But No Probing to ESDS
Voltage Static Charge Build-up Electrometer
Current
Transient Noise Tap Transient (CT-6)
Ground Noise Continuous Measurement (CT-6)
Dynamic: - Testers- Powered Tools With Direct Probing to ESDS
Voltage Signal Analysis Differential Voltage
Current
Ground Noise Measurement at the Probes (Static and Dynamic Mode)
Continuous Measurement (CT-6)
Tap Transient (Standby Mode)
Tap Transient (CT-6)
H-Fields EMI CheckEMI Sensor During Actual Testing/Probing
3. ESD Assessment
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Recommended Measurements…cont’d.
ESD EventsMeasurements
Category Parameters Method
Charged Device Model (CDM)
Resistance
Material Resistance Check (High Charge Generation/Inhibition of Charge Dissipation)
MOM
Ground or Discharge Path DMM
E-FieldsStatic Field Charge Check (FIM) Fieldmeter/Charge Plate Analyzer
Point Charge Check Nanocoulomb Meter
Voltage
Tribocharge Check (Handling/Process/Operation)
Electrometer
Unbalanced Ionizer Electrometer/CPM
Current CDM Discharge Current Tap Transient (CT-6) to the device
3. ESD Assessment
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
2. Process Benchmarking
Systematic Approach in ESD Auditing
3. ESD Assessment
4. Perform Measurements
5. Modeling and Simulation
6. ESD Control Conceptualization
1. Failure Mode Identification
Course Outline
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Voltage
Static – From electrostatic charge.
Dynamic – Potential from constant voltage sources such as testers or power supplies.
- The difference in electric potential between two points.
4. Perform Measurements
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Voltage Measuring Equipment and Probes
Electrometer Triax Probe
Single-Ended Voltage Active Probe
Voltage Active Differential ProbeDigital Oscilloscope
Keithley 6517A Electrometer
4. Perform Measurements Voltage
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Active Differential Probe and Oscilloscope
Voltage Measurement - Dynamic Voltage
To Oscilloscope
Source (I) +/- Electronics
Device Under Test (DUT)
Voltage Active Differential Probe
Measures the differential voltage between the channel that injects signal to the DUT.
4. Perform Measurements Voltage
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Current
Static – Transient current from electrostatic charge / discharge.
– Current leaks from tools, machines, or equipment. Can cause ground noise.
- Flow of electric charge.
Dynamic
– Noise or glitch from HF signal of testers.
4. Perform Measurements
- Energy sensitive devices are damaged by excessive current.
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Current Probes
Tek CT-1 and CT-2 Probes
Tek CT-6 Probe
4. Perform Measurements Current
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Tap Transient
Current Measurement - Static
Tester or metallic tool with electrical circuits/motors
Source (I) +/- Electronics
Time (50 ns/div)
Vol
tage
(1
00 m
V/d
iv)
Simulated Device’s Resistance
CT-6 Probe
MM Transient Wave Form
To Oscilloscope
Simulated device’s resistance. Tap Transient Testing for static measurement, at single
shot mode.
4. Perform Measurements Current
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Continuous Ground Noise Measurement
Current Measurement - Dynamic
Noise Propagation from the Ground to the Jigs/Fixtures.
Peak Current: 10.7 mAFreq: 9.137 MHz
Current Waveform
CT-6 ProbeTool/Machine
Jigs/Fixture
Continuous Transient Testing for at dynamic condition, using Norm mode.
4. Perform Measurements Current
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Fields (E-Field and H-Field)
Voltage/Current Transients = E-field
Device Under Test (DUT)
Probe Pins (Dipole) acts like antenna
Source (I) +/- Electronics
4. Perform Measurements
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Field Probes
3M (Credence) EM Aware
Sanki EMI Locator
Novx 7000
Antenna Connected in Digital Oscilloscope
4. Perform Measurements Fields (E-Field and H-Field)
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
2. Process Benchmarking
Systematic Approach in ESD Auditing
3. ESD Assessment
4. Perform Measurements
5. Modeling and Simulation
6. ESD Control Conceptualization
1. Failure Mode Identification
Course Outline
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
5. PSPICE Modeling and Simulation
SPICE
Simulation Program with Integrated Circuit Emphasis
General-purpose circuit program that simulates electronic circuits.
Used to perform various analyses:
- time-domain response- frequency response,- operating points or transistors, and so on.
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
5. PSPICE Modeling and Simulation
PSPICE on ESD
Mostly, the Transient Analysis is being used in ESD Simulation.
Transient Analysis:
- Used for circuits with time-variant sources (AC or switched DC sources)
- Calculates all node voltages and branch currents over time interval.
Done to understand the sources and behavior of ESD, and determine how to control the sources.
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
5. PSPICE Modeling and Simulation
Transient Analysis…cont’d.
Voltage Sources
Pulsed Voltage Source
PSPICE Model
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
5. PSPICE Modeling and Simulation
Sinusoidal Voltage Source
Transient Analysis…cont’d. Voltage Sources…cont’d.
PSPICE Model
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
5. PSPICE Modeling and Simulation
ESD Events Simulation – Transient Analysis
- Human Body Model (HBM)- Machine Model (MM)
- Charge Device Model (CDM)
HBM Simulated Circuit CDM Simulated Circuit MM Simulated Circuit
Run PSPICE
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
2. Process Benchmarking
Systematic Approach in ESD Auditing
3. ESD Assessment
4. Actual Measurements
5. Modeling and Simulation
6. ESD Control Conceptualization
1. Failure Mode Identification
Course Outline
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Key Considerations
Elimination of the HF voltage/current source
Current Suppression
Current Diversion
6. ESD Control Conceptualization
Run PSPICE
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Thank You!Thank You!
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Back-up
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Discussion
Basic PSPICE Simulation
How to start the simulation?
- Simulation should be based on the actual condition.
- Prior ESD measurements should be made.
Transient Noise Measurements
RLC components identification.
Power source consideration.
L = 20 nH per inch of ground wire C for charge storage
“Manufacturing and R&D : Leveling Up the Philippines’ Capability ”
Discussion
PSPICE Simulation Workshop
Actual PSPICE Simulation
- Understanding HF Noise from stepper motors, transformers, HV sources, etc.
- Charge Decay Simulation (Spot Decay Test Using CPM)
- Tools and series resistance