Reliability Report

AOS Semiconductor
Product Reliability Report
AO4704/AO4704L,
rev C
Plastic Encapsulated Device
ALPHA & OMEGA Semiconductor, Inc
495 Mercury Drive
Sunnyvale, CA 94085
U.S.
Tel: (408) 830-9742
www.aosmd.com
May 11, 2006
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This AOS product reliability report summarizes the qualification result for AO4704. 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 AO4704 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 AO4704 uses advanced trench technology to provide excellent RDS(ON), shoot-through
immunity and body diode characteristics. This device is suitable for use as a synchronous switch
in PWM applications. The co-packaged Schottky Diode boosts efficiency further. AO4704 is Pbfree (meets ROHS & Sony 259 specifications). AO4704L is a Green Product ordering option.
AO4704 and AO4704L 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
±12
V
ID
13
Continuous
Drain Current
TA=25°C
TA=70°C
10.4
Pulsed Drain Current
IDM
Schottky reverse voltage
VKA
Continuous
Forward Current
TA=25°C
TA=70°C
Pulsed Forward Current
Power
Dissipation
TA=25°C
TA=70°C
Junction and Storage
Temperature Range
30
3.2
IFM
TJ, TSTG
V
4.4
IF
PD
A
40
A
30
3.1
3.1
2
2
W
-55 to 150
-55 to 150
°C
2
Thermal Characteristics
MOSFET
Maximum Junctiont ≤ 10s
to-Ambient
Maximum JunctionSteadyto-Ambient
State
Maximum JunctionSteadyto-Lead
State
Thermal Characteristics
Schottky
Maximum Junctiont ≤ 10s
to-Ambient
Maximum JunctionSteadyto-Ambient
State
Maximum JunctionSteadyto-Lead
State
Symbol
Typ
Max
28
40
54
75
RθJL
21
30
Symbol
Typ
Max
36
40
67
75
25
30
RθJA
RθJA
RθJL
Units
°C/W
Units
°C/W
II. Die / Package Information:
Process
AO4704
AO4704L (Green Compound)
Standard sub-micron
Standard sub-micron
low voltage N channel process low voltage N channel process
Package Type
Lead Frame
Die Attach
Bond wire
Mold Material
Filler % (Spherical/Flake)
Flammability Rating
Backside Metallization
Moisture Level
8 lead SOIC
Copper with Solder Plate
Silver epoxy
2 mils Au wire
Epoxy resin with silica filler
90/10
UL-94 V-0
Ti / Ni / Ag
Up to Level 1 *
8 lead SOIC
Copper with Solder Plate
Silver epoxy
2 mils Au wire
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 AO4704 (Standard) & AO4704L (Green)
Test Item
Test Condition
Time Point
Solder
Reflow
Precondition
Standard: 1hr PCT+3
cycle reflow@260°c
Green: 168hr 85°c
/85%RH+3 cycles
reflow@260°c
Temp = 150°c,
Vgs=100% of Vgsmax
0hr
HTGB
168 / 500
hrs
Lot Attribution
Standard: 87 lots
Green: 29 lots
5 lots
(Note A*)
Total
Sample size
Number of
Failures
17380 pcs
0
410 pcs
0
77+5 pcs / lot
1000 hrs
HTRB
Temp = 150°c,
Vds=80% of Vdsmax
168 / 500
hrs
5 lots
(Note A*)
410 pcs
0
77+5 pcs / lot
1000 hrs
HAST
Pressure Pot
130 +/- 2°c, 85%RH,
33.3 psi, Vgs = 80% of
Vgs max
121°c, 15+/-1 PSIG,
RH=100%
100 hrs
Standard: 81 lots
Green: 16 lots
5335 pcs
0
50+5 pcs / lot
96 hrs
(Note B**)
Standard: 83 lots
Green: 20 lots
5665 pcs
0
50+5 pcs / lot
Temperature
Cycle
DPA
-65°c to 150°c ,
air to air,
250 / 500
cycles
(Note B**)
Standard: 87 lots
Green: 29 lots
6380 pcs
0
50+5 pcs / lot
Internal Vision
Cross-section
X-ray
CSAM
(Note B**)
5
5
5
5
5
5
0
NA
5
5
0
NA
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 AO4704 and AO4704L
burn-in data up to the published date.
Note B: The pressure pot, temperature cycle and HAST reliability data for AO4704 and AO4704L
comes from the AOS generic package qualification data.
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IV. Reliability Evaluation
FIT rate (per billion): 11.7
MTTF = 9756 years
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 (AO4704). 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 [(2×164)×(168) (258) + (164)×(500) (258)+ (164) × (1000) (258)] = 11.7
MTTF = 109 / FIT = 8.54 x 107 hrs = 9756 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
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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