MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第121页

MIL-STD-883F METHOD 1019.6 7 March 2003 5 3.9.3 Bi as and loadi ng condit ions. Bias c onditi ons for test devices during i rradi ation or accel erated anneal ing shal l be withi n ± 10 perc ent of t hose s pecif ied by …

MIL-STD-883F

METHOD 1019.6

7 March 2003

3.6.2 Condition B.

For condition B, for MOS devices only, if the maximum dose rate is < 50 rad(Si)/s in the intended

application, the parties to the test may agree to perform the test at a dose rate ≥ the maximum dose rate of the intended

application. Unless the exclusions in 3.12.1b are met, the accelerated annealing test of 3.12.2 shall be performed.

3.6.3 Condition C.

For condition C, (as an alternative) the test may be performed at the dose rate agreed to by the

parties to the test.

3.6.4 Condition D

. For condition D, for bipolar or BiCMOS linear or mixed-signal circuits only, the parts shall be

irradiated at <

10 mrad(Si)/s unless the specification dose is greater than 25 krad(Si). For radiation levels greater than 25

krad(Si) the total irradiation time shall be >

1000 hours and the dose rate shall be determined from the total dose (including

any overtest factors) and the irradiation time.

3.6.5 Condition E

. For condition E, for bipolar or BiCMOS linear or mixed-signal circuits only, the parts shall be

irradiated at between 0.5 and 5 rad(Si)/s if the specification dose is <

50 krad(Si). Condition E applies to elevated

temperature irradiation at 100°C ±5°C and does not apply for devices with specification doses >50 krad(Si) unless it can be

demonstrated that the elevated temperature irradiation test provides a conservative bound for low dose rate response at a

radiation specification level that is above 50 krad(Si).

3.7 Temperature requirements

. The following requirements shall apply for room temperature and elevated temperature

irradiation.

3.7.1 Room temperature irradiation

. Since radiation effects are temperature dependent, devices under test shall be

irradiated in an ambient temperature of 24°C ±6°C as measured at a point in the test chamber in close proximity to the test

fixture. The electrical measurements shall be performed in an ambient temperature of 24°C ±6°C. If devices are

transported to and from a remote electrical measurement site, the temperature of the test devices shall not be allowed to

increase by more than 10°C from the irradiation environment. If any other temperature range is required, it shall be

specified.

3.7.2 Elevated temperature irradiation.

For bipolar or BiCMOS linear or mixed-signal circuits irradiated using Condition E

dose rate, devices under test shall be irradiated in an ambient temperature of 100°C ±5°C as measured at a point in the test

chamber in close proximity to the test fixture.

3.8 Electrical performance measurements

. The electrical parameters to be measured and functional tests to be

performed shall be specified in the test plan. As a check on the validity of the measurement system and pre- and post-

irradiation data, at least one control sample shall be measured using the operating conditions provided in the governing

device specifications. For automatic test equipment, there is no restriction on the test sequence provided that the rise in the

device junction temperature is minimized. For manual measurements, the sequence of parameter measurements shall be

chosen to allow the shortest possible measurement period. When a series of measurements is made, the tests shall be

arranged so that the lowest power dissipation in the device occurs in the earliest measurements and the power dissipation

increases with subsequent measurements in the sequence.

The pre- and post-irradiation electrical measurements shall be done on the same measurement system and the same

sequence of measurements shall be maintained for each series of electrical measurements of devices in a test sample.

Pulse-type measurements of electrical parameters should be used as appropriate to minimize heating and subsequent

annealing effects. Devices which will be subjected to the accelerated annealing testing (see 3.12) may be given a

preirradiation burn-in to eliminate burn-in related failures.

3.9 Test conditions

. The use of in-flux or not in-flux testing shall be specified in the test plan. (This may depend on the

intended application for which the data are being obtained.) The use of in-flux testing may help to avoid variations

introduced by post-irradiation time dependent effects. However, errors may be incurred for the situation where a device is

irradiated in-flux with static bias, but where the electrical testing conditions require the use of dynamic bias for a significant

fraction of the total irradiation period. Not-in-flux testing generally allows for more comprehensive electrical testing, but can

be misleading if significant post-irradiation time dependent effects occur.

3.9.1 In-flux testing

. Each test device shall be checked for operation within specifications prior to being irradiated. After

the entire system is in place for the in-flux radiation test, it shall be checked for proper interconnections, leakage (see 2.4),

and noise level. To assure the proper operation and stability of the test setup, a control device with known parameter values

shall be measured at all operational conditions called for in the test plan. This measurement shall be done either before the

insertion of test devices or upon completion of the irradiation after removal of the test devices or both.

3.9.2 Remote testing

. Unless otherwise specified, the bias shall be removed and the device leads placed in conductive

foam (or similarly shorted) during transfer from the irradiation source to a remote tester and back again for further irradiation.

This minimizes post-irradiation time dependent effects.

MIL-STD-883F

METHOD 1019.6

7 March 2003

3.9.3 Bias and loading conditions.

Bias conditions for test devices during irradiation or accelerated annealing shall be

within ±10 percent of those specified by the test plan. The bias applied to the test devices shall be selected to produce the

greatest radiation induced damage or the worst-case damage for the intended application, if known. While maximum

voltage is often worst case some bipolar linear device parameters (e.g. input bias current or maximum output load current)

exhibit more degradation with 0 V bias. The specified bias shall be maintained on each device in accordance with the test

plan. Bias shall be checked immediately before and after irradiation. Care shall be taken in selecting the loading such that

the rise in the junction temperature is minimized.

3.10 Post-irradiation procedure

. Unless otherwise specified, the following time intervals shall be observed:

a. The time from the end of an irradiation to the start of electrical measurements shall be a maximum of 1 hour unless

Condition D is used, in which case the maximum time shall be 72 hours.

b. The time to perform the electrical measurements and to return the device for a subsequent irradiation, if any, shall

be within two hours of the end of the prior irradiation unless Condition D is used, in which case the maximum time

shall be 120 hours.

To minimize time dependent effects, these intervals shall be as short as possible. The sequence of parameter

measurements shall be maintained constant throughout the tests series.

3.11 Extended room temperature anneal test

. The tests of 3.1 through 3.10 are known to be overly conservative for

some devices in a very low dose rate environment (e.g. dose rates characteristic of space missions). The extended room

temperature anneal test provides an estimate of the performance of a device in a very low dose rate environment even

though the testing is performed at a relatively high dose rate (e.g. 50-300 rad(Si)/s). The procedure involves irradiating the

device per steps 3.1 through 3.10 and post-irradiation subjecting the device under test to a room temperature anneal for an

appropriate period of time (see 3.11.2c) to allow leakage-related parameters that may have exceeded their pre-irradiation

specification to return to within specification. The procedure is known to lead to a higher rate of device acceptance in cases:

a. where device failure when subjected to the tests in 3.1 through 3.10 has been caused by the buildup of trapped

positive charge in relatively soft oxides, and

b. where this trapped positive charge anneals at a relatively high rate.

3.11.1 Need to perform an extended room temperature anneal test

. The following criteria shall be used to determine

whether an extended room temperature anneal test is appropriate:

a. The procedure is appropriate for either MOS or bipolar technology devices.

b. The procedure is appropriate where only parametric failures (as opposed to functional failure) occurs. The parties

to the test shall take appropriate steps to determine that the device under test is subject to only parametric failure

over the total ionizing dose testing range.

c. The procedure is appropriate where the natural annealing response of the device under test will serve to correct the

out-of-specification of any parametric response. Further, the procedure is known to lead to a higher rate of device

acceptance in cases where the expected application irradiation dose rate is sufficiently low that ambient

temperature annealing of the radiation induced trapped positive charge can lead to a significant improvement of

device behavior. Cases where the expected application dose rate is lower than the test dose rate and lower than

0.1 rad(Si)/s should be considered candidates for the application of this procedure. The parties to the test shall

take appropriate steps to determine that the technology under test can provide the required annealing response

over the total ionizing dose testing range.

3.11.2 Extended room temperature anneal test procedure

. If the device fails the irradiation and testing specified in 3.1

through 3.10, an additional room temperature annealing test may be performed as follows:

a. Following the irradiation and testing of 3.1 through 3.10, subject the device under test to a room temperature

anneal under worst-case static bias conditions. For information on worst case bias see 3.9.3,

MIL-STD-883F

METHOD 1019.6

7 March 2003

b. The test will be carried out in such a fashion that the case of the device under test will have a temperature within

the range 24°C ± 6°C.

c. Where possible, the room temperature anneal should continue for a length of time great enough to allow device

parameters that have exceeded their pre-irradiation specification to return to within specification or post-irradiation-

parametric limit (PIPL) as established by the manufacturer. However, the time of the room temperature anneal

shall not exceed t

max

, where

spec

max

spec

is the total ionizing dose specification for the part and R

max

is the maximum dose rate for the intended use.

d. Test the device under test for electrical performance as specified in 3.7 and 3.8. If the device under test passes

electrical performance tests following the extended room temperature anneal, this shall be considered acceptable

performance for a very low dose rate environment in spite of having previously failed the post-irradiation and

electrical tests of 3.1 through 3.10.

3.12 MOS accelerated annealing test

. The accelerated annealing test provides an estimate of worst-case degradation of

MOS microcircuits in low dose rate environments. The procedure involves heating the device following irradiation at

specified temperature, time and bias conditions. An accelerated annealing test (see 3.12.2) shall be performed for cases

where time dependent effects (TDE) can cause a device to degrade significantly or fail. Only standard testing shall be

performed as specified in 3.1 through 3.10 for cases where TDE are known not to cause significant device degradation or

failure (see 3.12.1) or where they do not need to be considered, as specified in 3.12.1.

3.12.1 Need to perform accelerated annealing test

. The parties to the test shall take appropriate steps to determine

whether accelerated annealing testing is required. The following criteria shall be used:

a. The tests called out in 3.12.2 shall be performed for any device or circuit type that contains MOS circuit elements

(i.e., transistors or capacitors).

b. TDE tests may be omitted if:

1. circuits are known not to contain MOS elements by design, or

2. the ionizing dose in the application, if known, is below 5 krad(Si), or

3. the lifetime of the device from the onset of the irradiation in the intended application, if known, is short

compared with TDE times, or

4. the test is carried out at the dose rate of the intended application, or

5. the device type or IC technology has been demonstrated via characterization testing not to exhibit TDE

changes in device parameters greater than experimental error (or greater than an otherwise specified upper

limit) and the variables that affect TDE response are demonstrated to be under control for the specific vendor

processes.

At a minimum, the characterization testing in (5) shall include an assessment of TDE on propagation delay,

output drive, and minimum operating voltage parameters. Continuing process control of variables affecting

TDE may be demonstrated through lot sample tests of the radiation hardness of MOS test structures.

c. This document provides no guidance on the need to perform accelerated annealing tests on technologies that do

not include MOS circuit elements.