Prez REL Test-7

8/6/2019 Prez REL Test-7

http://slidepdf.com/reader/full/prez-rel-test-7 1/20

RELIABILITY AND DIAGNOSTIC

Faculty of Electronic Engineering and

Technologies

Anna Andonova

E-mail: [email protected]



Definitions - determine the ability of Items to withstand

moderately severe shocks resulting from suddenly applied

forces or abrupt changes in motion encountered during

mishandling, improper transportation, or field operation

Shocks cause devices to degrade in performance, or to even

get damaged permanently

Repetitive shocks cause damage that is similar to thosecaused by extreme vibration

Testing requires shock pulses of 500 to 30,000 g (peak), with

the pulse width or duration ranging from 0.1 to 1 millisecond

RELIABILITY TESTS

Test Condition g Level (peak) Pulse Duration (ms)

A 500 1

B 1,500 0.5

C 3,000 0.3

D 5,000 0.3

E 10,000 0.2

F 20,000 0.2

G 30,000 0.12

Test Conditions for Mechanical ShockTesting per Mil-Std-883 Method 2002

The samples shall be subjected to

shock pulses in each of the followingorientations: X1, X2, Y2, Y1, Z1, Z2.

After test has been completed, external

visual inspection of the case, leads, and

seals shall be performed at 10 X to 20 X

Mechanical Shock Test



Definitions - to determine the resistance of the part to

sudden changes in temperature

The parts undergo a specified number of cycles

Start at ambient temperature then to an extremely low (or

high) temperature and, within a short period of time to an

extremely high (or low) temperature, before going back toambient temperature

Repetitive shocks cause damage that is similar to those

caused by extreme vibration

After the final cycle, external visual examination of the case,

leads, and seals shall be performed at 10 X to 20 X.

Electrical testing must also be performed to detect electrical

failures accelerated by the temp cycle

RELIABILITY TESTS

Thermal Shock

Chamber

Thermal Shock (TST)



Failure acceleration due to Thermal Shock and Temp

Cycling depends on the following factors:

the difference between the high and low temperatures used

the transfer time between the two temperatures

the dwell times at the extreme temperatures

Failure mechanisms accelerated by thermal shock include

die cracking

package cracking

neck/heel/wire breaks

bond lifting

RELIABILITY TESTSThermal Shock (TST)

Mil-Std-883 Method 1011 Specs : Thermal Shock Test

- Total Transfer Time < 10 seconds

- Total Dwell Time > 2 minutes

- Specified Temp reached in < 5 minutes

- Must be conducted for a minimum of 15 cycles

Condition Low Temp High Temp

A -40 (+0/-30) deg C 85 (+10/-0) deg C

B -0 (+2/-10) deg C 100 (+10,-2) deg C

C -55 (+0,-10) deg C 125 (+10,-0) deg C

D -65 (+0,-10) deg C 150 (+10,-0) deg C

For reliability testing or

qualification of new

devices, 1000 temp cycles

are usually performed



Definition - ability to resist extremely low

and extremely high temperatures, as well

as ability to withstand cyclical exposures

to these temperature extremes

(TST) closely resembles TCT and also

accelerates fatigue failures

subjecting the parts to the specified low

(or high) temperature then to the specified

high (or low) temperature for a specified

number of cycles

after the final cycle, external visualexamination and electrical testing to

device specifications shall be performed

RELIABILITY TESTSTemperature Cycle Testing (TCT)

Temperature Cycle Chambers



Failure mechanisms include

die cracking

package cracking

neck/heel/wire breaks

bond lifting.

For reliability testing or

qualification of new devices,

1000 temp cycles are usually

performed

RELIABILITY TESTSTemperature Cycle Testing (TCT)

Condition Low Temp High Temp

A -55 (+0/-10) deg C 85 (+10,-0) deg C

B -55 (+0/-10) deg C 125 (+15,-0) deg C

C -65 (+0/-10) deg C 150 (+15,-0) deg C

D -65 (+0/-10) deg C 200 (+15,-0) deg C

E -65 (+0/-10) deg C 300 (+15,-0) deg C

F -65 (+0/-10) deg C 175 (+15,-0) deg C

Mil-Std-883 Method 1010 Temp Cycle

Test Conditions

- Total Transfer Time <= 1 minute

- Total Dwell Time >= 10 minutes

- Specified Temp reached in <= 15

minutes

- Must be conducted for a minimum of 10

cycles



Definition - accelerate metal corrosion,particularly that of the metallizations

to provide the potential differences

needed to trigger the corrosion process,

as well as to drive mobile contaminants

to areas of concentration

stress conditions: 1000 hours at 85 deg

C, 85% RH, with bias applied to the device

intermediate readpoints at 48H, 96H,

168H, and 500H are often used

long duration, necessitating weeksbefore useable data are obtained

an alternative test, the HAST, has been

developed - more severe stress

conditions but shorter duration

RELIABILITY TESTSTemperature, Humidity, Bias (THB)

Temperature/Humidity

Chambers



Definition - a shorter alternative to (THB)

if THB testing takes 1000 H to complete, HAST

results are available within 96-100 H

requires preconditioning conducted with electrical

bias at 130 deg C and 85% RH for 96-100 H

electrical bias must be defined on:

power dissipation must be minimized to ensure that

moisture is always present at the surface

alternate pins must be subjected to opposite bias

(low voltage versus high voltage) as much as possible

potential differences between the various

metallizations on the die must be maximized

the operating voltage range for the device must also

be maximized, as long as the power dissipation is

kept under control

RELIABILITY TESTSHighly Accelerated

Temperature/Humidity Stress

Test (HAST)

HAST system



Definition - determine the reliability of devices under

operation at high temperature conditions over an

extended period of time

subjecting the parts to a specified bias or electrical

stressing, for a specified amount of time, and at a

specified high temperature (essentially just a long-term burn-in)

unlike production burn-in which accelerates early

life failures, HTOL testing is

applied to assess the potential operating lifetimes

(steady-state 'life test')

more concerned with acceleration of wear-out

failures

test duration may be decreased by increasing the

ambient temperature

RELIABILITY TESTSHigh Temperature

Operating Life (HTOL)

Burn-in Ovens



if not specified, an intermediateelectrical testing shall be performed

after 168 (+72,-0) H and after 504

(+168,-0) H

accomplished by utilizing any burn-

in oven capable of operating

continuously over long durations

failure mechanisms include

Time-Dependent Dielectric

Breakdown (TDDB)

electromigration

hot carrier effects

charge effects

mobile ionic contamination

RELIABILITY TESTSHigh Temperature

Operating Life (HTOL)

Mil Std 883 Method 1005 Specs :

- generally 1000 hours min. at 125 deg C

- max. rated Tc or Ta < 200 deg C (Class B)

- max. rated Tc or Ta < 175 deg C (Class S)

- Condition A : steady-state, reverse bias

- Condition B : steady-state, forward bias

- Condition C : steady-state, power/reverse bias

- Condition D : steady-state, parallel excitation

- Condition E : steady-state, ring oscillator

- Condition F : steady-state, temp.-accelerated



Definition - determine the reliability of devices under low temperature conditions over an extended period

of time

subjecting the parts to a specified bias or electrical

stressing, for a specified amount of time, and at a

specified low temperature

low temperature equivalent of the HTOL test

there are several requirements when powering up a

device

the device must not be overstressed nor should it

go to thermal runaway datasheet limits of the manufacturer must not be

exceeded

stressing must also be continuous, and should only

be interrupted at interim readpoints if required

RELIABILITY TESTSLow Temperature

Operating Life (LTOL)

LowTemperature

Burn-in Oven



biasing configuration may be

static

pulsed

even dynamic

ambient temperature shall not exceed the maximum limit of -10 deg C electrical testing must be performed within 96 hours after the bias to

the device has been removed

device is considered an LTOL failure if it fails to meet the applicable

procurement specification

test is usually performed to check for

hot carrier effects

commonly encountered failure mechanism accelerated by high

voltages and low temperatures

RELIABILITY TESTSLow Temperature

Operating Life (LTOL)



Definition - determine the effect on devices of long-term storage at elevated temperatures

without any electrical stresses applied

similar to Stabilization Bake (storing the parts

at the specified ambient temperature for a

specified amount of time) except that

HTS is done over a much longer period of time

(1000 H vs. 24 H for Stab Bake at 150 deg C)

purpose of HTS is to assess the long-term

reliability of devices under high temperature

conditions while that of Stabilization bake is

merely to serve as part of a screening sequenceor as a preconditioning treatment prior to the

conduct of other tests

RELIABILITY TESTSHigh-Temperature Storage (HTS)

Bake

Chamber/Oven

that

can be used for

High

Temperature

Storage



devices must be allowed toreach the specified

temperature before the

duration starts counting

end-point measurements

must be conducted within 96

H after the specified testconditions are removed

end-point measurements

include external visual

inspection and electrical

testing effective for the reliability

testing of samples in terms of

mechanisms accelerated by

temperature only

RELIABILITY TESTSHigh-Temperature Storage (HTS)

Summary of industry-standard HTS conditions: 1000

hours at 150 deg C.

Mil Std 883, Method 1008, Stabilization Bake Specs :

- storage at a high temperature for a specified duration

- Test Condition A : 75 deg C / 24 H minimum

- Test Condition B : 125 deg C / 24 H minimum

- Test Condition C : 150 deg C / 24 H minimum

- Test Condition D : 200 deg C / 24 H minimum

- Test Condition E : 250 deg C / 24 H minimum

- Test Condition F : 300 deg C / 24 H minimum

- Test Condition G : 350 deg C / 24 H minimum

- Test Condition H : 400 deg C / 24 H minimum



consists of three steps:

a bake to drive away all the moisture within the samples a temperature/humidity soak to drive controlled amounts of moisture into the

package

a form of thermal shock simulating the soldering process itself

accelerated failure mechanism

popcorn cracking

neck breaking and ball lifting

die cracking

moisture-related failure mechanisms may also arise but these should

generally not be considered as valid SHRT failures

baking is usually done for 24 hours at 125 deg C or 8 hours at 150 deg C

Soaking is usually done at 85 deg C/85% RH or 30 deg C/60%RH, for a

duration ranging from 24 hours to 192 hours

The shock is often done three times, and should be completed within 4 hours

after the soak

RELIABILITY TESTSSolder Heat Resistance Test (SHRT)



Definition - assess the ability of a product towithstand severe temperature and humidity

conditions

used primarily to accelerate corrosion in the

metal parts of the product

consists of soaking the samples for 168 hours at121 deg C, 100% RH, and 2 atm

intermediate readpoints at 48H and 96H may be

employed

Surface-mount samples are preconditioned prior

to autoclave testing PCT failures

arising from corrosion

moisture-related electrical leakage failures must

not be considered

RELIABILITY TESTSAutoclave Test, or Pressure Cooker Test

(PCT), or Pressure Pot Test (PPOT)

Autoclave

Chamber



Package Dimensions Test

Definition - examination to verify that the external physical dimensions of thedevice are in accordance with the applicable acquisition document

Constant Acceleration Test

Definition - determine the ability of parts to withstand high levels of constant

acceleration

used as

an indicator of the mechanical strength limits of a package

an in-line screen for parts with structural or mechanical weaknesses

The Mechanical Shock Test

Definition - determine the suitability of a device to be used in electronicequipment that will be subjected to moderately severe shocks from suddenly

applied forces or abrupt changes in motion

The Resistance to Solvents Test

Definition - determines the ability of a part to withstand exposure to solvents

RELIABILITY TESTSOther reliability tests



consists of immersing three (3) different groups of specimens in 3 different

solvent solutions for a minimum of 1 minute

solution composed of 80% kerosene/20% ethylbenzene

semi-aqueous based solvent (defluxer)

composed of 42 pbv DI water, 1 pbv monoethanolamine, and 1 pbv propylene

glycol monomethyl ether

after immersion, the specimen is brushed

immersion and brush cycle is conducted two more times for a total of three

cycles, after which the parts are rinsed and blow-dried

The Salt Atmosphere Test

Definition - accelerated laboratory corrosion test to simulate the effects of seacoast atmosphere on the device and package

consists of exposing the units to a salt fog, which is produced by atomizing a

salt solution

after the exposure, the units shall be washed with free-flowing D/I water for at

least 5 minutes




The Vibration Test (Variable Frequency)

Definition - determine the ability of parts to withstand vibration of varying

frequency within a specified frequency range, and is considered to be

destructive

consists of subjecting the parts to a variable frequency vibration at specified

levels

achieved by simple harmonic motion having a peak-to-peak amplitude of

about 0.06 inch or a peak acceleration corresponding to the specified test

condition

the vibration frequency shall be varied approximately logarithmically between

20 to 2,000 Hz

The Vibration Test (Fatigue)

Definition - determine the ability of parts to withstand sustained vibration of

constant amplitude within a specified frequency range

consists of subjecting the parts to a constant amplitude simple harmonic

motion having a peak acceleration corresponding to the specified test condition


Prez REL Test-7

Documents

Transcript of Prez REL Test-7