MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第119页

MIL-STD-883F METHOD 1019.6 7 March 2003 3 2.8 The ir radiati on temperat ure chamber . The ir radiat ion temperat ure, i f requi red for elevated temper ature i rradi ation s hould be capable of maintai ning a ci rcui t …

MIL-STD-883F

METHOD 1019.6

7 March 2003

2.2 Dosimetry system

. An appropriate dosimetry system shall be provided which is capable of carrying out the

measurements called for in 3.2. The following American Society for Testing and Materials (ASTM) standards and guidelines

or other appropriate standards and guidelines shall be used:

ASTM E 666 - Standard Method for Calculation of Absorbed Dose from Gamma or X Radiation.

ASTM E 668 - Standard Practice for the Application of Thermoluminescence Dosimetry (TLD) Systems

for Determining Absorbed Dose in Radiation-Hardness Testing of Electronic Devices.

ASTM E 1249 - Minimizing Dosimetry Errors in Radiation Hardness Testing of Silicon Electronic Devices.

ASTM E 1250 - Standard Method for Application of Ionization Chambers to Assess the Low Energy Gamma

Component of Cobalt 60 Irradiators Used in Radiation Hardness Testing of Silicon Electronic

Devices.

ASTM E 1275 - Standard Practice for Use of a Radiochromic Film Dosimetry System.

ASTM F 1892 - Standard Guide for Ionizing Radiation (Total Dose) Effects Testing of Semiconductor Devices.

These industry standards address the conversion of absorbed dose from one material to another, and the proper use of

various dosimetry systems. 1

2.3 Electrical test instruments

. All instrumentation used for electrical measurements shall have the stability, accuracy,

and resolution required for accurate measurement of the electrical parameters. Any instrumentation required to operate in a

radiation environment shall be appropriately shielded.

2.4 Test circuit board(s)

. Devices to be irradiated shall either be mounted on or connected to circuit boards together with any

associated circuitry necessary for device biasing during irradiation or for in-situ measurements. Unless otherwise specified, all

device input terminals and any others which may affect the radiation response shall be electrically connected during irradiation,

i.e., not left floating. The geometry and materials of the completed board shall allow uniform irradiation of the devices under test.

Good design and construction practices shall be used to prevent oscillations, minimize leakage currents, prevent electrical

damage, and obtain accurate measurements. Only sockets which are radiation resistant and do not exhibit significant leakages

(relative to the devices under test) shall be used to mount devices and associated circuitry to the test board(s). All apparatus

used repeatedly in radiation fields shall be checked periodically for physical or electrical degradation. Components which are

placed on the test circuit board, other than devices under test, shall be insensitive to the accumulated radiation or they shall be

shielded from the radiation. Test fixtures shall be made such that materials will not perturb the uniformity of the radiation field

intensity at the devices under test. Leakage current shall be measured out of the radiation field. With no devices installed in the

sockets, the test circuit board shall be connected to the test system such that all expected sources of noise and interference are

operative. With the maximum specified bias for the test device applied, the leakage current between any two terminals shall not

exceed ten percent of the lowest current limit value in the pre-irradiation device specification. Test circuit boards used to bias

devices during accelerated annealing must be capable of withstanding the temperature requirements of the accelerated

annealing test and shall be checked before and after testing for physical and electrical degradation.

2.5 Cabling

. Cables connecting the test circuit boards in the radiation field to the test instrumentation shall be as short as

possible. If long cables are necessary, line drivers may be required. The cables shall have low capacitance and low

leakage to ground, and low leakage between wires.

2.6 Interconnect or switching system

. This system shall be located external to the radiation environment location, and

provides the interface between the test instrumentation and the devices under test. It is part of the entire test system and

subject to the limitation specified in 2.4 for leakage between terminals.

2.7 The environmental chamber

. The environmental chamber for time-dependent effects testing, if required, shall be

capable of maintaining the selected accelerated annealing temperature within ±5°C.

/ Copies may be obtained from the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.

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.