MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第151页

MIL-STD-883F METHOD 1023.2 19 August 1994 3 2.3 D ose Ra te Test Sy stem . The ins trument ation s hall be c apable of es tablis hing the r equired t est c onditi ons and measuri ng and recor ding the r equired par amete…

MIL-STD-883F

METHOD 1023.2

19 August 1994

1.3 Formulation of the upset criteria

. The upset criteria are usually generated from characterization data at the dose rate

of interest. Upset criteria can sometimes be determined by analysis/simulation (SPICE or equivalent computer code) of the

application circuit, if the code has been verified to agree with experimental data for similar circuits and exposure conditions.

1.4 Specification of the

upset criteria. Once formulated, the upset criteria shall be specified in the detailed specification.

The upset criteria may consist of the following (a waveform may be included denoting the acceptable boundaries):

a. Measurement circuit to which criteria apply.

b. Peak amplitude of tolerable transient change in output voltage.

c. Allowable duration of transient output change (recovery time).

d. Limiting value for the surge in power supply current and recovery characteristics.

e. Steady state (return to normalcy) level of the output voltage following recovery.

f. ENOB or missing codes for ADCs.

g. Delta parameters such as Vref or VOH.

h. Device saturation time.

2. APPARATUS

. The apparatus shall consist of the radiation source, dosimetry equipment, remote test circuit to include

signal recording devices, cabling, line drivers, interconnect fixture, and exposure board. Adequate precautions shall be

observed to obtain an electrical measurement system with sufficient insulation, ample shielding, satisfactory grounding and

low noise from electrical interference or from the radiation environment (see section 3.7.3).

2.1 Radiation Source

. Either of two radiation sources shall be used for dose rate testing: 1) a flash x-ray machine

(FXR), or 2) an electron linear accelerator (LINAC). The FXR shall be used in the x-ray mode and the LINAC in the electron

(e-beam) mode. Unless otherwise specified, the FXR peak charging voltage shall be 2 MV or greater, and the LINAC beam

energy shall be 10 MeV or greater. The uniformity of the radiation field in the device irradiation volume shall be +

15% as

measured by the dosimetry system. The dose per radiation exposure shall be as specified in the test plan or procedure.

2.2 Dosimetry System

. A dosimetry system shall be used which provides a measurement accuracy within + 15 percent.

A calibrated PIN diode may be used to obtain both the shape of the radiation pulse and the dose. The following American

Society for Testing and Materials (ASTM) standards or their equivalent may be used:

ASTM E 526 Standard Method for Measuring Dose for Use in Linear Accelerator Pulsed Radiation Effects Tests.

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

ASTM E 668 Standard Practice for the Application of Thermo-luminescence Dosimetry (TLD) Systems for Determining

Absorbed Dose in Radiation Hardness Testing of Electronic Devices.

These methods describe techniques to determine the absorbed dose in the material of interest. Device packaging material

and thickness should be considered in determining the dose to the DUT. For FXR tests, dose enhancement effects of the

package shall be considered. Dosimetry techniques shall be reported in the test report as well as device packaging

material, thickness and dose enhancement effects, if applicable.

MIL-STD-883F

METHOD 1023.2

19 August 1994

2.3 Dose Rate Test System

. The instrumentation shall be capable of establishing the required test conditions and

measuring and recording the required parameters in the specified time frame. Components other than the device under test

(DUT) shall be insensitive to the expected radiation levels, or they shall be shielded from the radiation. The system used for

dose rate testing shall contain the following elements:

2.3.1 Remote Test circuit

. The remote portion of the test circuit includes power sources, input and control signal

generators, instrumentation for detecting, measuring and recording transient and steady state response, and may also

include automated test equipment (ATE). The remote portion of the test equipment is shielded from radiation and from

radiation induced electromagnetic fields. Specified signals shall be measured and recorded during the radiation pulse, and

the logic pattern shall be verified after the pulse (when applicable).

2.3.2 Interconnect fixture

. The interconnecting fixture is located in the radiation exposure chamber and is connected to

the remote portion of the test circuit via the cabling system. It serves as a power and signal distribution box and contains

the line drivers that buffer the various DUT output signals. The characteristics of the line drivers (e.g., linearity, dynamic

range, input capacitance, transient response and radiation response) shall be such that they accurately represent the

response of the DUT output. The interconnect fixture shall be located as close as practical to the exposure fixture, and must

be appropriately shielded against scattered radiation fields so that radiation induced effects do not adversely affect the

fidelity of the output response being measured.

2.3.3 Test circuit

. The test circuit for each device type shall provide worst case bias and load conditions for the DUT, and

shall enable in-situ functional testing of the DUT as specified in the test plan or procedure. The test circuit accommodates

the DUT, output loads, and the supply stiffening capacitors connected directly to the DUT supply pins or its socket (see

2.3.4). To avoid ground loops, there shall be only one ground plane (or ground rings connected to a single ground) on the

test circuit. Test Circuit parasitic resistance shall be kept to a minimum.

2.3.4 Stiffening capacitors

. A high frequency capacitor shall be placed at each bias supply pin of the DUT with lead

lengths as short as practicable. These capacitors should be large enough such that the power supply voltage drop at the

DUT is less than 10% during the radiation pulse (typical values are between 4.7 and 10 µF). In parallel with this capacitor

should be a low inductance capacitor (e.g., 0.1 µF), again as close as possible to the supply pin and with lead lengths as

short as practical. In addition, for each supply line into the DUT, a larger capacitor, >

100 µF, may be placed a short

distance away from the DUT and shielded from radiation.

2.3.5 Current Limiting Series resistor

. A current limiting resistor in series with the power supply may only be used with

prior approval of the acquiring activity. Note that a current limiting resistor may degrade the upset performance of the DUT.

2.3.6 Timing control

. A timing control system shall be incorporated into the test system such that post-irradiation in-situ

functional testing is performed at the specified time, and that recovery of the signal and supply current can be monitored.

2.4 Cabling

. The remote test circuit shall be connected to the interconnect and exposure fixtures by means of shielded

cables terminated in their characteristic impedance. Additional shielding provisions (e.g., doubly shielded cables, triax,

zipper tubing, aluminum foil) may be required to reduce noise to acceptable levels.

2.5 Measuring and recording equipment

. Oscilloscopes or transient waveform digitizers shall be used to measure and

record the transient signal and the recovery period of the output voltage and supply current. The rise time of these

instruments shall be such that they are capable of accurately responding to the expected pulse width(s).

3. PROCEDURE

3.1 Device identification

. In all cases, devices shall be serialized, and the applicable recorded test data shall be

traceable to each individual device.

MIL-STD-883F

METHOD 1023.2

19 August 1994

3.2 Radiation safety

. All personnel shall adhere to the health and safety requirements established by the local radiation

safety officer or health physicist.

3.3 Stress limits.

3.3.1 Total ionizing dose limit

. Unless otherwise specified, any device exposed to more than 10% of its total ionizing

dose limit shall be considered to have been destructively tested. The total dose limit shall be determined (or data obtained)

for each device type to be tested. The total ionizing dose limit shall be specified in the test plan.

3.3.2 Burnout Limit.

A device exposed to greater than 10% of the level at which photocurrent burnout occurs shall be

considered destructively tested. The burnout level shall be specified in the test plan/procedure. The burnout level may be

specified as the maximum dose rate level at which the device type has been tested and does not burnout. Note that dose

rate testing causes surge currents ranging from 20 ns to 500 ns (typically) in duration, which may exceed the manufacturers'

maximum ratings for current and power for that time period.

3.4 Characterization testing

. Characterization tests shall be performed or data obtained to determine device performance

as a function of dose rate and to establish requirements for production testing, if applicable. The following are examples of

information gained from characterization testing:

a. Parameter behavior over dose rate and pulse width.

b. Upset threshold as a function of radiation dose rate and pulse width.

c. Determination of susceptible circuit conditions.

d. Identification of the most susceptible circuits of a device, and the appropriate outputs to monitor.

e. Effect of temperature on upset or failure.

f. Upset, recovery time and failure criteria to be specified in the device specification or drawing.

g. Group A electrical parameter degradation subsequent to dose rate testing.

h. Worst case power supply voltage.

i. Maximum surge currents and duration, and photocurrent burnout level.

3.5 Production testing

. Prior to production testing, characterization testing shall be performed or characterization data

obtained for each device type. The results of the characterization tests (paragraph 3.4), or the existing data, will be used to

develop the requirements for the production tests. These requirements are specified in the applicable test plan or procedure

and include those items listed in paragraph 1.2.

3.5.1 General requirements for production tests.

Production tests shall be performed at the specified dose rates (and

pulse widths), with bias and load conditions as specified in the test plan or procedure. The measured response shall be

compared to the upset criteria and determination of pass/fail shall be made. Devices having storage elements shall be

loaded with the applicable test pattern prior to exposure and post-exposure functional test shall be performed to the extent

necessary to verify the stored pattern.

3.6 Testing of Complex Linear Devices

. Testing of complex linear devices, such as analog to digital and digital to

analog converters, shall be performed using the necessary (as specified in the test plan or procedure) exposure conditions

to ensure adequate coverage. Often, four or more exposure conditions are required. To the greatest extent practical, the

most susceptible exposure conditions (i.e., most favorable for upset to occur) shall be used. For linear devices that have

storage elements, each exposure state shall consist of a stored test pattern plus the external bias. Each test pattern shall

be loaded prior to exposure, and following the application of the radiation pulse, functional testing of the device must be

performed to the extent necessary to verify the pattern.