MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第150页

MIL-STD-883F METHOD 1023.2 19 August 1994 2 1.3 Formul ation of the upset cri teri a . The upset cri teri a are usual ly generat ed from c haract erizat ion data at the dose r ate of inter est. Upset c rit eria c an some…

MIL-STD-883F

METHOD 1023.2

19 August 1994

METHOD 1023.2

Dose Rate Response and Threshold for Upset

of Linear Microcircuits

1. PURPOSE

. This test procedure defines the requirements for measuring the dose rate response and upset threshold

of packaged devices containing analog functions when exposed to radiation from a flash X-ray source or from a linear

accelerator. This procedure addresses the measurement of dose rate response characteristics of a linear circuit, excluding

latchup which is addressed in MIL-STD-883 Test Method 1020.

1.1 Definitions

. The following are the definitions of terms used in this method:

a. Dose rate response

. The transient changes which occur in the operating parameters or in the output signal of an

operating linear microcircuit when exposed to a pulse of ionizing radiation.

b. Dose rate

. Energy absorbed per unit time and per unit mass by a given material from the radiation field to which it

is exposed. Units are specified in Gray (Gy) per second (s) in the material of interest, e.g., Gy(Si)/s, Gy(SiO

)/s,

Gy(GaAs)/s, etc.

c. Dose rate induced upset

. An upset has occurred when the radiation induced transient change in a specified

parameter (e.g., in output voltage, supply current, output signal waveform) exceeds a predetermined level.

d. Upset threshold

. The upset threshold is the minimum dose rate at which the device upsets. However, the

reported measured upset threshold shall be the maximum dose rate at which the device does not upset and which

the transient disturbance of the output waveform and/or supply current remains within the specified limits.

1.2 Test plan

. Prior to dose rate testing, a test plan shall be prepared which describes the radiation source, the

dosimetry techniques, test equipment, the device to be tested, test conditions, and any unique testing considerations. A

detailed procedure for each device type to be tested shall be prepared, either as part of the test plan, or in separate test

procedure documents. The procedure shall include bias conditions, test sequence, schematics of the test setup and specific

functions to be tested. The test plan shall be approved by the acquiring activity, and as a minimum, the items listed below

shall be provided in the test plan or procedure:

a. Device types, including package types, manufacturer, date codes, and quantities to be tested.

b. Traceability requirements, such as requirements for serialization, wafer or lot traceability, etc.

c. Requirements for data reporting and submission.

d. Block diagram or schematic representation of test set up.

e. List of equipment used in the testing and calibration compliance requirements as required.

f. Test conditions, e.g., bias voltage, temperature, etc.

g. Electrical parameters to be monitored and device operating conditions, including functional test requirements

before, during and after the radiation pulse. Test patterns to be used for devices with storage elements, or

devices with input pattern sensitivity shall also be specified.

h. Group A electrical test requirements for pre- and post-dose rate testing, when applicable, to include test limits and

failure criteria.

i. Radiation test parameters such as pulse width(s), radiation dose(s) per pulse and dose rate range(s).

j. Total ionizing dose limit acceptable for each device type.

k. Upset and failure criteria, e.g., effective number of bits (ENOB) or missing codes in analog to digital converters

(ADCs), delta VOH or Vref, time to recovery, output waveform distortion in shape or frequency, etc.

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.