 APPENDIX

Table A1
- Package Related Failure Mechanisms Identified with Plastic and Hermetic IC's
DESCRIPTION |
STRESS/SOURCE |
RESPONSE |
ACCELERATING TEST |
PLASTIC |
HERMETIC |
Cracked Die |
Thermal |
Electrical Short/Open |
Temperature Cycle |
X |
X |
Mechanical |
Electrical Short/Open |
Impact Shock |
|
X |
Wire Breaks |
Thermal |
Electrical Open |
Temperature Cycle |
X |
X |
Mechanical |
Electrical Open |
Vibration, Centrifuge |
|
X |
Wire Lifts |
Thermal |
Electrical Open |
Temperature Cycle |
X |
X |
Mechanical |
Electrical Open |
Vibration, Centrifuge |
|
X |
Wire Lifts (intermetallic) |
Thermal |
Electrical Open |
High Temperature Storage |
X |
X |
Cracked Package Seals |
Thermal |
Loss of Hermeticity |
Temperature Cycle |
|
X |
Mechanical |
Loss of Hermeticity |
Impact Shock |
|
X |
Corroded Seals, external
(Pin-to-Pin Shorts) |
Moisture |
Loss of Hermeticity |
Humidity,
Salt Atmosphere |
|
X |
Interface Delamination |
Thermal |
Reduced Moisture Resistance |
Temperature Cycle |
X |
|
Internal Water Vapor |
Package Assembly |
Al Corrosion |
Low Temperature
Bias Life |
|
X |
Moisture Ingress |
Moisture |
Al Corrosion |
Temperature/Humidity/Bias
Autoclave, HAST |
X |
|
SMD
Cracked Package
(Popcorn Effect) |
Thermal |
Reduced Moisture Resistance/Elect. Opens |
Humidity/Solder Shock
Sequence |
X |
|
Metal Deformation/ Cracked Passivation |
Thermal |
Electrical Shorts/Opens |
Temperature Cycle |
X |
|
Lifted
Die |
Thermal Mechanical |
Electrical Shorts/Open
Thermal Designation |
Temperature Cycle Impact
Shock, Centrifuge |
|
X |
Die
Attach Voids |
Package Assembly |
Thermal Dissipation
Low D/A Strength Cracked Die |
Bias Life Temp Cycle,
Centrifuge |
X |
X |
Loose Die Attach, Sealing Materials, and Particles |
Package Assembly |
Electrical Shorts |
Vibration/Shock PIND |
|
X |
Table A2 - Comparison of General Industry Sampling &
Qualifications for Military Hermetic Versus Automotive Plastic Microcircuits
DESCRIPTION
OF TEST |
MILITARY HERMETIC
(Mil. Std. 883) |
AUTOMOTIVE PLASTIC
(Typical) |
LTPD |
#LOTS |
DURATION |
LTPD |
#LOTS |
DURATION |
Burn-In 100% |
(PDA = 5%) |
All |
168 Hours |
(PDA = 0.5-2.0%*) |
All |
48-168 Hours |
Operating Life Qualification |
5 |
1 |
1k Hours |
2 - 3 |
1 or 3 |
1k - 2k Hours |
Biased Humidity Qualification |
Not
Specified |
Not Specified |
Not Specified |
2 - 3 |
1 or 3 |
1k - 2k Hours |
Temp Cycle Qualification |
15 |
1 |
100 Cycles |
1.5 - 3 |
1 or 3 |
1k Cycles |
Mechanical Qualification |
15 |
1 |
- - - |
Not
Specified |
Not
Specified |
Not
Specified |
Group A Sampling |
2 |
All |
- - - |
1 |
All |
- - - |
* Values are for when PDA is specified. Sample burn-in to LTPD of
2% typically performed when PDA not specified.
Note: This chart compares
similar stress conditions with the exception of biased humidity and mechanical. |
Table A3 - Reliability Monitors - Comparison of Military
Hermetic and Intersil Plastic
HERMETIC MILITARY (MIL-STD-883)
QUALITY CONFORMANCE INSPECTION (QCI) |
PLASTIC COMMERCIAL
MATRIX MONITOR |
DESCRIPTION |
SAMPLE/
ACC. NO. |
FREQUENCY |
DESCRIPTION |
SAMPLE/
ACC. NO. |
FREQUENCY |
Group B
Resistance to Solvents
Bond Strength
Solderability(8 Hours Steam
Age) |
3/0
22/0
10/0 |
Each Lot
Each Lot
Each Lot |
Matrix I
HTOL (125°C or 175°C, 48
Hours)
HAST (135°C/85% R.H., 48
Hours)
Autoclave (96 Hours)
Thermal Shock (200 Cycles) |
45/0
45/0
45/0
45/0 |
2X/Month
2X/Month
2X/Month
2X/Month |
Group C
HTOL (125°C, 1k Hours) |
45/0 |
1X/12 Months |
Matrix II
HTOL (125°C, 1k Hours)
THB (85/85, 1k Hours)
Autoclave (192 Hours)
Storage Life (150°C, 1k
Hours)
Temp Cycle (1k Cycles) |
45/0
45/0
45/0
45/0
45/0 |
1X/Month
1X/Month
1X/2 Months
1/2 Months
1X/2 Months |
Group D
1. Physical Dimensions
2. Lead Integrity
3. Thermal Shock (15 Cycles)
Temp Cycle (100 Cycles)
Moisture Resist (10 Cycles)
4. Shock
Vib. Var. Freq.
Acceleration
5. Salt Atm. (24-240 HPS)
6. Internal Wafer Vapor
7. Adhesion of Lead Finish
8. Lid Torque |
15/0
15/0
15/0
15/0
15/0
3/0
15/0
5/0 |
1X/6 Months
1X/6 Months
1X/6 Months
1X/6 Months
1X/6 Months
1X/6 Months
1X/6 Months
1X/6 Months |
Matrix III
Solderability (8 Hrs. Steam
Age)
Brand Adherence
Lead Integrity
Physical Dimensions
Flammability UL-94
SPC Monitored (Eqv. to
Hermetic)
Bond Strength
Die Shear
Solderability >4 Hours
Steam Age
>8 Hours Steam Age |
22/0
15/0
15/0
11/0
5/0
SPC
SPC - Z Chart
Recording
Recording |
2X/Month
1X/Month
1X/Month
1X/Month
1X/Quarter
1X/Shift
1X/Oven/Cycle
1X/Shift
1X/Week |
Note: Mil-Std-883 requires assembly locations to have an
additional monitor program to Mil-Std-976 (i.e., Bond Strength/Die Shear, etc.) which has
not been covered by this table. |
Table A4 - Best Industry Practices - Design for
Reliability and Continuous Improvement
DIE RELATED |
IMPACT ON RELIABILITY |
 | Electric (E) Field Plating |
|
 | Reduces mobile ion instability |
|
 | Particulate & Contaminant Control |
|
 | Lowers defects in oxides and ionic contamination |
|
 | Layout considerations for high stress areas. |
|
 | Reduces stress cracking of passivation at die corners. |
|
 | Denser passivation, sandwich layers of SiO2/SiNx |
|
 | Better integrity against fabrication defects. |
 | Robust to thermomechanical stress. |
 | Better moisture/ion barrier.
|
|
 | Passivation overlap of die oxide edges. |
|
 | Provides moisture/ion barrier |
|
 | Advanced planarization for reduced stress |
|
 | Reduced metal displacement and passivation damage. |
|
 | Wear-out failure mechanisms eliminated from useful life at the die level. |
|
 | Elimination from useful life the intrinsic wear-out failure mechanisms EM
(Electromigration), TDDB (Time Dependant Dielectric Breakdown), Hot carrier injection,
Corrosion, and Device Stability. |
|
 | Reliability critical process node list. |
|
 | SPC control of variables effecting quality and reliability |
|
|
| PACKAGE RELATED |
IMPACT ON RELIABILITY |
 | Mold compounds: |
|
|
 | Higher glass transition temperatures. |
|
 | Less thermomechanical stress at high temperatures |
 | More robust to thermal cycling |
|
 | Low ionic (Low Halides, and Alkali) compounds |
|
 | Reduced corrosion and increased device stability |
|
 | Use of modified filler material. |
|
 | Reduced point stress damage on die surface. |
|
 | Low stress mold compounds
for large die and complex
geometries. |
|
 | Reduced passivation cracking and metal deformation |
|
 | Ion getters. |
|
 | Corrosion reduction and greater device stability. |
|
 | Reduced frame retardants |
|
 | High temperature stability and corrosion reduction |
|
 | Automated in-line mold machines |
|
 | Less wire sweep. |
 | Less voids in plastic |
 | Better control of molding process |
|
 | Die attach materials with low stress, low ionics. |
|
 | Less stress on die |
 | Increased device stability |
|
 | Lead lock holes, moisture groves, locking bars on lead frame. |
|
 | Increased moisture resistance and corrosion reduction. |
 | Increased mechanical integrity |
|
 | Optimum die to paddle spacing. |
|
 | Lower stress on die |
|
 | Automated assembly processes |
|
 | No human handling, less contamination, and less process variability |
|
 | SPC critical node list and process monitors. |
|
 | Variability reduction and Continuous Improvement. |
|
|
EXPANDED MATERIALS CHARACTERIZATION |
IMPACT ON RELIABILITY |
 | Acoustic Microscopy
 | CSAM |
 | SLAM |
|
|
 | Non destructive analysis of Plastic products for voids, die cracks, and
delamination isolation. DOX with CSAM yields Continuous Improvement. |
|
 | Thermal Characterization Methods:
 | Differential scanning calorimetry |
 | Thermogravimetric analysis |
 | Thermomechanical analysis |
|
|
 | Broader materials characterization and referencing enhances continuous
improvement of raw materials. |
|
 | Moisture weight gain/loss measurements
|
|
 | Determine sensitivity to delamination and popcorn cracking. |
 | Material analysis |
 | Determine dry pack requirements. |
|
 | Applications of dye penetrants |
|
 | Being further developed to enhance tracing moisture ingress on lead frame
to Plastic interfaces. |
|
|
Table A5 - ASIC Wafer fabrication, 6", Critical Node
List Example
MAJOR FLOW STEP |
CRITICAL PARAMETER |
TYPE OF CONTROL |
CRITICAL NODE YES/NO |
EPI Deposition
P-Diffusion
Sink Deposition
Nitride Dep & Etch
Local Oxidation
BN Drive
Gate Oxidation
Poly Deposition
Poly Doping
Poly Etch
DMOS Drive
N+/P+ Ion Implant
Interlevel Dielectric
First Metal Deposition
First Metal Etch
Intermetal Dielectric
Sec. Metal Deposition
Second Metal Etch
Passivation Deposition
In-Line Probe |
Sheet Resistance
EPI Thickness
Oxide Thickness
Sheet Resistance
Post Etch Dimension
Oxide Thickness
Sheet Resistance
Oxide Thickness
Poly Thickness
Sheet Resistance
Post Etch Dimension
Oxide Thickness
Sheet Resistivity
Oxide Thickness
Deposition Rate
Thickness
Post Etch Dimension
Thickness
Reflectivity
Oxide Thickness
Deposition Rate
Post Etch Dimension
Passivation Thickness
Device Parameters |
XBAR-R
XBAR-R
XBAR-R
XBAR-R
XBAR-R
XBAR-R
XBAR-R
XBAR-R
XBAR-R
XBAR-R
Z-Chart
XBAR-R
XBAR-R
XBAR-R
XBAR-R
XBAR-R
XBAR-R
XBAR-R
XBAR-R
XBAR-R
XBAR-R
Z-Chart
XBAR-R
Test Site Sample |
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO |
Note: Other general or tool related critical controls such as
Capacitance Voltage (CV) test for the cleanliness of furnaces and deposition tools are
maintained in-line. |
Table A6 - Plastic DIP Assembly Critical Node List
MAJOR FLOW STEP |
CRITICAL PARAMETER |
TYPE OF CONTROL |
CRITICAL NODE YES/NO |
Wafer Mount
Saw
Die Visual
QC Lot Acceptance
Die Attach
Die Attach Cure
Wire Bond
QC Lot Acceptance
Mold
Chemical Deflash
Mold Cure
Trim/Form
Solder DIP
QA Lot Acceptance
Brand
QA Lot Acceptance
To Test |
Kerf width, DI
Resistivity
Visual Quality
Visual Quality
Visual Quality
Oven Temp
Die Shear
Pull Strength
Visual
Temp
Force
Ball Shear
Visual Quality
Visual Quality
X-Ray
Visual Quality
Oven Temp
Visual Quality
Visual Quality
Solder Thickness
Solderability
Visual Quality
Brand Perm
Visual Quality |
XBAR-R
Monitor
AQL
AQL
NP-Chart
XBAR-R
Z-Chart
XBAR-R
NP-Chart
XBAR-R
XBAR-R
XBAR-R
AQL
NP-Chart
AQL
NP-Chart
XBAR-R
NP-Chart
AQL
XBAR-R
AQL
NP-Chart
AQL
AQL |
NO
YES
YES
NO
YES
YES
YES
NO
YES
YES
YES
YES
YES
NO
YES
NO |
Table A7 -
Best Practices Recommended for PEM Handling and Board/System Processing
PROBLEM |
PREVENTION |
Storage
|
|
 | Environmental vapors in ambient and moisture
can be corrosive to the leads of packages and cause dendritic growth on insulating
surfaces between leads.
|
 | Storage environment if moist can lead to moisture uptake in plastic. With
voids or delamination, accumulation of monolayers of moisture and contaminants can change
pH or conductivity of moisture sufficiently to start galvanic corrosion of metallization.
|
|
 | Control environmental ambient gases. Dry N2 storage. |
 | Eliminate Human handling of product. |
 | Dry N2 purge storage, minimize storage time.
|
|
 | Storage in moist environments may lead to "Popcorn Cracking" or
delamination in certain surface mount device packages during solder reflow operations.
|
|
 | Dry pack (sensitive package types) |
 | Store surface mount devices at <30°C and <55% R.H. |
|
Electrostatic Discharge (ESD) -
applicable to hermetic and PEMs
|
|
 | Human handling without proper ESD prevention can lead to damaged
products. |
 | Dropping parts out of tubes or in handlers onto a grounded surface can
lead to triboelectric charge damage as well as non destructive oxide charging (surface
leakage and reflected leakage). |
 | Handlers that have ESD hot zones due to a lack of grounding or oxidized
surface such as anodized surfaces, floating rails, etc., can cause ESD damage. |
 | Conformal coating materials sprayed on PCB's can develop extreme ESD
potential. Also sprayed DI water is an ESD source. |
|
 | Use monitored wrist straps at work station, with ionization if necessary. |
 | Reduce sliding packages on insulated surfaces. |
 | Reduce dropping distance or purge with ionization. |
 | ESD gauge all handlers, pick and place machines, belt transports and
transition points for charged surfaces. Improve grounding and charge dissipation |
 | Adjust coating and cleaning processes to minimize charging, i.e., use
ionization, add CO2 to DI water, etc. Low pressure applications. |
 | Follow Mil-Handbook 263, |
 | ESD Control Handbook Mil-Std 1686, JEDEC,
Pub 108-A
|
|
Handling to
Prevent External Contamination
|
|
 | Human handling contaminants (body oils, salts, makeup, lotions) on the
external surfaces of a package may diffuse through plastic with moisture, leading to ionic
instability or corrosion. |
|
 | Use automated pick and place equipment. |
 | If handled, use clean, ESD safe cots or gloves which have been shown not
to transfer residuals or ionic contaminants to surfaces. |
 | Thorough board cleaning. |
|
Processing Without
Halides
|
|
 | Halides in flux or cleaning agents or residual halides on boards may
diffuse through the plastic with moisture and lead to corrosion of bond pads, interconnect
and lead frame.
|
|
 | Use high purity electronic grade halide free flux's and paste as well
other high purity chemicals in board assembly or coat processes. |
 | Thorough board cleaning. |
|
Alkali Metal Ion Free
Processing
|
|
 | Alkali metal Ions (positive or cations) such
as Na+, Li+, K+ are mobile and can cause surface leakage and device drift. |
|
 | Use high purity electronic grade materials,
gases, and liquids that certify as alkali free. |
 | Control particle counts and analyze residue for alkali metals. Eliminate
sources. |
 | Eliminate human handling. |
 | Thorough board cleaning.
|
|
Surface Mount
Device Solder Reflow
|
|
 | Thermal Shock due to temperature gradient and peak/temperature/time
excursions in combination with sufficient absorbed moisture can lead to delamination of
mold compound to die, paddle, and lead frame. |
|
 | Sensitive surface mount device packages not
dry packed should be baked dry at 125°C for 24 hours and used within 48 hours on board
attach. |
 | Use pre-heating in the solder attach process. |
 | Monitor temperature profiles of the solder attach equipment |
 | Pay special attention to the temp/time dwell of the peak solder
temperature zone. |
 | Standards - IPC, JEDEC A112
|
|
Metallic Free
Processing
|
|
 | Fine pitch packages, (<25 mils) are
susceptible by their reduced lead pitch to residual solder and metallic fines which react
with bias and moisture to cause leakage and shorts. |
|
 | Clean up residual solder paste and residual
solder. |
 | Eliminate sources of metallic fines in automated equipment. |
 | Conformal coat PCB or selected surface mount devices. |
 | Proper board packaging. |
|
|

Mil Plastic - 30 AUG 94
|