AOS Semiconductor Product Reliability Report AO4456/AO4456L

AOS Semiconductor
Product Reliability Report
AO4456/AO4456L,
rev A
Plastic Encapsulated Device
ALPHA & OMEGA Semiconductor, Inc
495 Mercury Drive
Sunnyvale, CA 94085
U.S.
Tel: (408) 830-9742
www.aosmd.com
Jul 11, 2006
1
This AOS product reliability report summarizes the qualification result for AO4456. Accelerated
environmental tests are performed on a specific sample size, and then followed by electrical test
at end point. Review of final electrical test result confirms that AO4456 passes AOS quality and
reliability requirements. The released product will be categorized by the process family and be
monitored on a quarterly basis for continuously improving the product quality.
Table of Contents:
I.
II.
III.
IV.
V.
I.
Product Description
Package and Die information
Environmental Stress Test Summary and Result
Reliability Evaluation
Quality Assurance Information
Product Description:
The AO4456 uses advanced trench technology with a monolithically integrated Schottky diode to
provide excellent RDS(ON),and low gate charge. This device is suitable for use as a low side FET in
SMPS, load switching and general purpose applications. Standard Product AO4456 is Pb-free
(meets ROHS & Sony 259 specifications). AO4456 is a Green Product ordering option. AO4456
and AO4456 are electrically identical.
Absolute Maximum Ratings TA=25°C unless otherwise noted
Parameter
Symbol
Maximum
Units
Drain-Source Voltage
VDS
30
V
Gate-Source Voltage
VGS
±12
V
Continuous Drain
Current
TA=25°C
TA=70°C
Pulsed Drain Current
TA=25°C
Power Dissipation
TA=70°C
Junction and Storage
Temperature Range
Thermal Characteristics
Parameter
Maximum Junction-toAmbient
Maximum Junction-toAmbient
Maximum Junction-to-Lead
20
ID
16
IDM
120
3.1
PD
W
2.0
TJ, TSTG
-55 to 150
Symbol
T ≤ 10s
SteadyState
SteadyState
A
RθJA
RθJL
°C
Typ
Max
Units
31
40
°C/W
59
75
°C/W
16
24
°C/W
2
II. Die / Package Information:
Process
Package Type
Lead Frame
Die Attach
Bond wire
Mold Material
Filler % (Spherical/Flake)
Flammability Rating
Backside Metallization
Moisture Level
AO4456
Standard sub-micron
low voltage N channel process
8 leads SOIC
Copper with Ag spot
Ag epoxy
Au, 2.75 mils
Epoxy resin with silica filler
90/10
UL-94 V-0
Ti / Ni / Ag
Up to Level 1 *
AO4456L (Green Compound)
Standard sub-micron
low voltage N channel process
8 leads SOIC
Copper with Ag spot
Ag epoxy
Au, 2.75 mils
Epoxy resin with silica filler
100/0
UL-94 V-0
Ti / Ni / Ag
Up to Level 1*
Note * based on info provided by assembler and mold compound supplier
III. Result of Reliability Stress for AO4456 (Standard) & AO4456L (Green)
Number
of
Failures
Test Item
Test Condition
Time
Point
Lot Attribution
Total
Sample
size
Solder
Reflow
Precondition
Standard: 1hr PCT+3
cycle [email protected]°c
Green: 168hr 85°c
/85%RH +3 cycle
[email protected]°c
Temp = 150°c ,
Vgs=100% of Vgsmax
0hr
Standard: 83 lots
Green: 29 lots
17380 pcs
0
168 / 500
hrs
3 lots
246 pcs
0
1000 hrs
(Note A*)
77+5 pcs /
lot
168 / 500
hrs
3 lots
246 pcs
1000 hrs
(Note A*)
77+5 pcs /
lot
100 hrs
Standard: 81 lots
Green: 16 lots
HTGB
HTRB
HAST
Pressure Pot
Temperature
Cycle
Temp = 150°c ,
Vds=80% of Vdsmax
130 +/- 2°c , 85%RH,
33.3 psi, Vgs = 80% of
Vgs max
121°c , 29.7 psi ,
100%RH
-65°c to 150°c ,
air to air
96 hrs
250 / 500
cycles
(Note B**)
Standard: 83 lots
Green: 20 lots
(Note B**)
Standard: 87 lots
Green: 29 lots
(Note B**)
0
5335 pcs
0
50+5 pcs /
lot
5665 pcs
0
50+5 pcs /
lot
6380 pcs
0
50+5 pcs /
lot
3
III. Result of Reliability Stress for AO4456 (Standard) & AO4456L (Green)
Continues
DPA
Internal Vision
Cross-section
X-ray
CSAM
NA
5
5
5
5
5
5
0
NA
5
5
0
Bond Integrity
Room Temp
150°c bake
150°c bake
0hr
250hr
500hr
40
40
40
40 wires
40 wires
40 wires
0
Solderability
230°c
5 sec
15
15 leads
0
Die shear
150°c
0hr
10
10
0
Note A: The HTGB and HTRB reliability data presents total of available AO4456 and AO4456L
burn-in data up to the published date.
Note B: The pressure pot, temperature cycle and HAST reliability data for AO4456 and AO4456L
comes from the AOS generic package qualification data.
IV. Reliability Evaluation
FIT rate (per billion): 14.4
MTTF =7927years
In general, 500 hrs of HTGB, 150 deg C accelerated stress testing is equivalent to 15 years of
lifetime at 55 deg C operating conditions (by applying the Arrhenius equation with an activation
energy of 0.7eV and 60% of upper confidence level on the failure rate calculation). AOS reliability
group also routinely monitors the product reliability up to 1000 hr at and performs the necessary
failure analysis on the units failed for reliability test(s).
The presentation of FIT rate for the individual product reliability is restricted by the actual burn-in
sample size of the selected product (AO4456). Failure Rate Determination is based on JEDEC
Standard JESD 85. FIT means one failure per billion hours.
Failure Rate = Chi2 x 109 / [2 (N) (H) (Af)] = 1.83 x 109 / [2 (3×164) (500) (258)] = 14.4
MTTF = 109 / FIT =6.94 x 107hrs = 7927 years
Chi² = Chi Squared Distribution, determined by the number of failures and confidence interval
N = Total Number of units from HTRB and HTGB tests
H = Duration of HTRB/HTGB testing
Af = Acceleration Factor from Test to Use Conditions (Ea = 0.7eV and Tuse = 55°C)
Acceleration Factor [Af] = Exp [Ea / k (1/Tj u – 1/Tj s)]
Acceleration Factor ratio list:
Af
55 deg C
70 deg C
85 deg C
100 deg C
115 deg C
130 deg C
150 deg C
258
87
32
13
5.64
2.59
1
Tj s = Stressed junction temperature in degree (Kelvin), K = C+273.16
Tj u =The use junction temperature in degree (Kelvin), K = C+273.16
k = Boltzmann’s constant, 8.617164 X 10-5eV / K
4
V. Quality Assurance Information
Acceptable Quality Level for outgoing inspection: 0.1% for electrical and visual.
Guaranteed Outgoing Defect Rate: < 25 ppm
Quality Sample Plan: conform to Mil-Std-105D
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