Reliability Report

AOS Semiconductor
Product Reliability Report
AO3438/AO3438L,
rev A
Plastic Encapsulated Device
ALPHA & OMEGA Semiconductor, Inc
495 Mercury Drive
Sunnyvale, CA 94085
U.S.
Tel: (408) 830-9742
www.aosmd.com
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This AOS product reliability report summarizes the qualification result for AO3438. 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 AO3438 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.
Product Description
Package and Die information
Environmental Stress Test Summary and Result
Reliability Evaluation
I. Product Description:
The AO3438/L uses advanced trench technology to provide excellent RDS(ON), low gate charge
and operation with gate voltages as low as 1.8V. This device is suitable for use as a load switch
or in PWM applications. AO3438 and AO3438L are electrically identical.
-RoHs Compliant
-AO3438L is Halogen Free
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II. Die / Package Information:
Process
Package Type
Lead Frame
Die Attach
Bond wire
Mold Material
Flammability Rating
Backside Metallization
Moisture Level
AO3438
Standard sub-micron
Low voltage N channel process
SOT23
Cu, S/pad, Ag spot
Ag epoxy
Au 2mils
Epoxy resin with silica filler
UL-94 V-0
Ti / Ni / Ag
Up to Level 1 *
AO3438L (Green Compound)
Standard sub-micron
Low voltage N channel process
SOT23
Cu, S/pad, Ag spot
Ag epoxy
Au 2 mils
Epoxy resin with silica filler
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 AO3438 (Standard) & AO3438L (Green)
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/85RH
+3 cycle
[email protected]°c
Temp = 150°c ,
Vgs=100% of Vgsmax
-
Standard: 19 lots
Green: 5 lots
3520 pcs
0
82 pcs
0
HTGB
168hrs
500 hrs
1000 hrs
Number
of
Failures
1 lot
77+5 pcs /
lot
(Note A*)
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 , 29.7psi,
RH=100%
-65 to 150°c ,
air to air,
168hrs
500 hrs
1000 hrs
1 lot
100 hrs
(Note A*)
Standard: 16 lots
Green: 2 lots
96 hrs
(note B**)
Standard: 18 lots
Green: 5 lots
250 / 500
cycles
82 pcs
0
77+5 pcs /
lot
(note B**)
Standard: 19 lots
Green: 4 lots
(note B**)
990 pcs
0
50+5 pcs /
lot
1265 pcs
0
50+5 pcs /
lot
1265 pcs
0
50+5 pcs /
lot
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III. Result of Reliability Stress for AO3438 (Standard) & AO3438L (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
245°c
5 sec
15
15 leads
0
Note A: The HTGB and HTRB reliability data presents total of available AO3438 and AO3438L
burn-in data up to the published date.
Note B: The pressure pot, temperature cycle and HAST reliability data for AO3438 and AO3438L
comes from the AOS generic package qualification data.
IV. Reliability Evaluation
FIT rate (per billion): 43
MTTF = 2639 years
The presentation of FIT rate for the individual product reliability is restricted by the actual burn-in
sample size of the selected product (AO3438). Failure Rate Determination is based on JEDEC
Standard JESD 85. FIT means one failure per billion hours.
2
9
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Failure Rate = Chi x 10 / [2 (N) (H) (Af)] = 1.83 x 10
9
7
MTTF = 10 / FIT = 2.31 x 10 hrs = 2639years
/ [2x164x500x258] = 43
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
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