III. Result of Reliability Stress for AOB11C60
Test Item
Test Condition Time
Point
Lot
Attribution
Total
Sample size of
Failures
Number
Reference
Standard
12 lots
2112pcs
0
0
0
0
JESD22-
A113
MSL
Precondition
-
168hr 85°c
/85%RH +3 cycle
reflow@250°c
168hrs
500 hrs
1000 hrs
539pcs
JESD22-
A108
HTGB
HTRB
HAST
Temp = 150°c ,
Vgs=100% of
Vgsmax
3 lots
4 lots
77 pcs / lot
539pcs
168hrs
500 hrs
1000 hrs
JESD22-
A108
Temp = 150°c ,
Vds=80% of
Vdsmax
3 lots
4 lots
77 pcs / lot
495pcs
96 hrs
9 lots
JESD22-
A110
130°c , 85%RH,
33.3 psi, Vgs =
100% of Vgs max
(Note A*)
9 lots
55 pcs / lot
693pcs
96 hrs
0
0
JESD22-
A102
Pressure Pot
121°c , 29.7psi,
RH=100%
(Note A*)
12 lots
77 pcs / lot
924pcs
250 / 500
cycles
JESD22-
A104
Temperature
Cycle
-65°c to 150°c ,
air to air,
(Note A*)
77 pcs / lot
IV. Reliability Evaluation
FIT rate (per billion): 4.16
MTTF = 27426 years
The presentation of FIT rate for the individual product reliability is restricted by the actual burn-in
sample size of the selected product (AOB11C60). Failure Rate Determination is based on JEDEC
Standard JESD 85. FIT means one failure per billion hours.
Failure Rate (FIT) = Chi2 x 109 / [2 (N) (H) (Af)]
= 1.83 x 109 / [2x (6x77x500 +8x77x1000) x259] = 4.16
MTTF = 109 / FIT = 2.40 x 108hrs = 27426 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:
55 deg C
70 deg C
85 deg C
32
100 deg C
13
115 deg C
5.64
130 deg C
2.59
150 deg C
1
Af
259
87
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
3
AOS [ ALPHA & OMEGA SEMICONDUCTORS ]
