MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第120页

MIL-STD-883F METHOD 1019.6 7 March 2003 4 3.6.2 Condi tion B. For condi tion B, f or MOS devic es only, if t he maximum dose rate i s < 50 rad( Si)/ s in the i ntended applic ation, the parti es to t he test may agree…

MIL-STD-883F

METHOD 1019.6

7 March 2003

2.8 The irradiation temperature chamber

. The irradiation temperature, if required for elevated temperature irradiation should

be capable of maintaining a circuit under test at 100 °C +

5 °C while it is being irradiated. The chamber should be capable of

raising the temperature of the circuit under test from room temperature to the irradiation temperature within a reasonable time

prior to irradiation and cooling the circuit under test from the irradiation temperature to room temperature in less than 20 minutes

following irradiation. The irradiation bias shall be maintained during the heating and cooling. The method for raising,

maintaining and lowering the temperature of the circuit under test may be by conduction through a heat sink using heating and

cooling fluids, by convection using forced hot and cool air, or other means that will achieve the proper results.

3. PROCEDURE

. The test devices shall be irradiated and subjected to accelerated annealing testing (if required for time-

dependent effects testing) as specified by a test plan. This plan shall specify the device description, irradiation conditions,

device bias conditions, dosimetry system, operating conditions, measurement parameters and conditions, and accelerated

annealing test conditions (if required).

3.1 Sample selection and handling

. Only devices which have passed the electrical specifications as defined in the test plan

shall be submitted to radiation testing. Unless otherwise specified, the test samples shall be randomly selected from the parent

population and identically packaged. Each part shall be individually identifiable to enable pre- and post-irradiation comparison.

For device types which are ESD-sensitive, proper handling techniques shall be used to prevent damage to the devices.

3.2 Burn-in

. For some devices, there are differences in the total dose radiation response before and after burn-in.

Unless it has been shown by prior characterization or by design that burn-in has negligible effect (parameters remain within

postirradiation specified electrical limits) on the total dose radiation response, then one of the following must be done:

3.2.1 The manufacturer shall subject the radiation samples to the specified burn-in conditions prior to conducting total

dose radiation testing or

3.2.2 The manufacturer shall develop a correction factor, (which is acceptable to the parties to the test) taking into

account the changes in total dose response resulting from subjecting product to burn-in. The correction factor shall then be

used to accept product for total dose response without subjecting the test samples to burn-in.

3.3 Dosimetry measurements

. The radiation field intensity at the location of the device under test shall be determined

prior to testing by dosimetry or by source decay correction calculations, as appropriate, to assure conformance to test level

and uniformity requirements. The dose to the device under test shall be determined one of two ways: (1) by measurement

during the irradiation with an appropriate dosimeter, or (2) by correcting a previous dosimetry value for the decay of the

source intensity in the intervening time. Appropriate correction shall be made to convert from the measured or calculated

dose in the dosimeter material to the dose in the device under test.

3.4 Lead/Aluminum (Pb/Al) container. Test specimens shall be enclosed in a Pb/Al container to minimize dose enhancement

effects caused by low-energy, scattered radiation. A minimum of 1.5 mm Pb, surrounding an inner shield of at least 0.7 mm Al, is

required. This Pb/Al container produces an approximate charged particle equilibrium for Si and for TLDs such as CaF

. The radiation

field intensity shall be measured inside the Pb/Al container (1) initially, (2) when the source is changed, or (3) when the orientation or

configuration of the source, container, or test-fixture is changed. This measurement shall be performed by placing a dosimeter (e.g., a

TLD) in the device-irradiation container at the approximate test-device position. If it can be demonstrated that low energy scattered

radiation is small enough that it will not cause dosimetry errors due to dose enhancement, the Pb/Al container may be omitted.

3.5 Radiation level(s)

. The test devices shall be irradiated to the dose level(s) specified in the test plan within ±10

percent. If multiple irradiations are required for a set of test devices, then the post-irradiation electrical parameter

measurements shall be performed after each irradiation.

3.6 Radiation dose rate

. The radiation dose rate for bipolar and BiCMOS linear or mixed-signal parts used in applications

where the maximum dose rate is below 50 rad(Si)/s shall be determined as described in paragraph 3.13 below. Parts used

in low dose rate applications, unless they have been demonstrated to not exhibit an ELDERS response shall use Condition

C, Condition D, or Condition E.

NOTE: Devices that contain both MOS and bipolar devices may require qualification to multiple subconditions to ensure that both

ELDRS and traditional MOS effects are evaluated.

3.6.1 Condition A.

For condition A (standard condition) the dose rate shall be between 50 and 300 rad(Si)/s [0.5 and 3

Gy(Si)/s]

Co 2/ The dose rates may be different for each radiation dose level in a series; however, the dose rate shall not

vary by more than ±10 percent during each irradiation.

2/ The SI unit for the quantity absorbed dose is the gray, symbol GY. 100 rad = 1 Gy.

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,