Reliability Report

AOS Semiconductor
Product Reliability Report
AO4702/AO4702L,
rev B
Plastic Encapsulated Device
ALPHA & OMEGA Semiconductor, Inc
495 Mercury Drive
Sunnyvale, CA 94085
U.S.
Tel: (408) 830-9742
www.aosmd.com
Oct 28, 2005
1
This AOS product reliability report summarizes the qualification result for AO4702. 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 AO4702 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.
Product Description
Package and Die information
Environmental Stress Test Summary and Result
Reliability Evaluation
Quality Assurance Information
I. Product Description:
The AO4702 uses advanced trench technology to provide excellent RDS(ON) and low gate charge.
A Schottky Diode is packaged in parallel to improve device performance in synchronous
recitification applications, or H-bridge configurations. Standard Product AO4702 is Pb-free (meets
ROHS & Sony 259 specifications). AO4702L is a Green Product ordering option. AO4702and
AO4702L are electrically identical.
Absolute Maximum Ratings TA=25°C unless otherwise noted
Parameter
Symbol
Mosfet
Schottky
Units
Drain-Source Voltage
VDS
30
V
Gate-Source Voltage
VGS
±20
V
Continuous Drain
Current
TA=25°C
11
A
ID
9.3
Pulsed Drain Current
IDM
50
Schottky reverse voltage
Continuous Forward
TA=25°C
Current
VKA
30
IF
4.4
TA=70°C
TA=70°C
V
3.2
A
IFM
30
Pulsed Diode Forward Current
TA=25°C
Power Dissipation
TA=70°C
Junction and Storage
Temperature Range
PD
TJ, TSTG
Thermal Characteristics: Mosfet
Parameter
Maximum Junction-tot ≤ 10s
Ambient
Maximum Junction-toSteadyAmbient
State
SteadyMaximum Junction-to-Lead
State
Symbol
RθJA
RθJL
3
3
2.1
2
-55 to 150
-55 to 150
W
°C
Typ
Max
Units
31
40
°C/W
59
75
°C/W
16
24
°C/W
2
Thermal Characteristics: Schottky
Parameter
Maximum Junction-tot ≤ 10s
Ambient
Maximum Junction-toSteadyAmbient
State
SteadyMaximum Junction-to-Lead
State
Symbol
RθJA
RθJL
Typ
Max
Units
36
40
°C/W
67
75
°C/W
25
30
°C/W
II. Die / Package Information:
Process
Package Type
Lead Frame
Die Attach
Bond wire
Mold Material
Filler % (Spherical/Flake)
Flammability Rating
Backside Metallization
Moisture Level
AO4702
Standard sub-micron
Low voltage N channel process
8 leads SOIC
Copper with Solder Plate
Ag epoxy
Au 2mils
Epoxy resin with silica filler
90/10
UL-94 V-0
Ti / Ni / Ag
Up to Level 1 *
AO4702L (Green Compound)
Standard sub-micron
Low voltage N channel process
8 leads SOIC
Copper with Solder Plate
Ag epoxy
Au 2 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
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III. Result of Reliability Stress for AO4702 (Standard) & AO4702L (Green)
Test Item
Test Condition
Time
Point
Lot Attribution
Total
Sample
size
Solder
Reflow
Precondition
Standard: 1hr PCT+3
cycle IR reflow@260 °c
Green: 168hr 85°°c
/85RH +3 cycle IR
reflow@260 °c
Temp = 150 C,
Vgs=100% of Vgsmax
0hr
Standard: 84 lots
Green: 17 lots
13878 pcs
HTGB
HTRB
HAST
Pressure Pot
Temperature
Cycle
Temp = 150 C,
Vds=80% of Vdsmax
130 +/- 2 C, 85%, 33.3
psi, Vgs = 80% of Vgs
max
121 C, 15+/-1 PSIG,
RH=100%
-65 to 150 deg C,
air to air, 0.5hr per
cycle
168 / 500
hrs
2 lots
1000 hrs
(note A*)
168 / 500
hrs
2 lots
1000 hrs
(note A*)
100 hrs
Standard: 53 lots
Green: 13 lots
96 hrs
250 / 500
cycles
(note B**)
Standard: 66 lots
Green: 16 lots
(note B**)
Standard: 84 lots
Green: 17 lots
(note B**)
DPA
Internal Vision
Cross-section
X-ray
CSAM
164 pcs
Number
of
Failures
0
0
77+5 pcs /
lot
164 pcs
0
77+5 pcs /
lot
3630 pcs
0
50+5 pcs /
lot
4510 pcs
0
50+5 pcs /
lot
5555 pcs
0
50+5 pcs /
lot
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 AO4702 and AO4702L
burn-in data up to the published date.
Note B: The pressure pot, temperature cycle and HAST reliability data for AO4702 and AO4702L
comes from the AOS generic green compound package qualification data.
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IV. Reliability Evaluation
FIT rate (per billion): 14
MTTF = 8154 years
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 (AO4702). Failure Rate Determination is based on JEDEC
Standard JESD 85. FIT means one failure per billion hours.
2
9
Failure Rate = Chi x 10 / [2 (N) (H) (Af)]
9
= 1.83 x 10 / [2 (164) (500) (258) + 2 (164) (1000) (258)] = 14
9
MTTF = 10 / FIT = 7.14 x 107hrs = 8154 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 = 55C)
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 E-5V / K
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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