1、Designation: F 773M 96 (Reapproved 2003)METRICStandard Practice forMeasuring Dose Rate Response of Linear IntegratedCircuits Metric1This standard is issued under the fixed designation F 773M; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the measurement of the response oflinear integrated circuits, under given o
3、perating conditions, topulsed ionizing radiation. The response may be either transientor more lasting, such as latchup. The radiation source is eithera flash X-ray machine (FXR) or an electron linear accelerator(LINAC).1.2 The precision of the measurement depends on thehomogeneity of the radiation f
4、ield and on the precision of theradiation dosimetry and the recording instrumentation.1.3 The test may be considered to be destructive either forfurther tests or for other purposes if the total radiation doseexceeds some predetermined level or if the part should latchup. Because this level depends b
5、oth on the kind of integratedcircuit and on the application, a specific value must be agreedupon by the parties to the test. (See 6.10.)1.4 Setup, calibration, and test circuit evaluation proceduresare included in this practice.1.5 Procedures for lot qualification and sampling are notincluded in thi
6、s practice.1.6 Because response varies with different device types, thedose rate range for any specific test is not given in this practicebut must be agreed upon by the parties to the test.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is
7、 theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:E 668 Practice for Application of Thermoluminescence-Dosimetry (TLD) Systems for Det
8、ermining Absorbed Dosein Radiation-Hardness Testing of Electronic Devices2F 526 Test Method for Measuring Dose for Use in LinearAccelerator Pulsed Radiation Effects Tests33. Terminology3.1 Definitions:3.1.1 dose rateenergy absorbed per unit time and per unitmass by a given material from the radiatio
9、n to which it isexposed.3.1.2 dose rate responsethe change that occurs in anobserved characteristic of an operating linear integrated circuitinduced by a radiation pulse of a given dose rate.4. Summary of Practice4.1 The test device and suitable dosimeters are irradiated bya pulse from either an FXR
10、 or a LINAC while the test deviceis operating under agreed-upon conditions. The responses ofthe test device and of the dosimeters are recorded.4.2 The response of the test device to dose rate is recordedover a specified dose rate range.4.3 A number of factors are not defined in this practice, andmus
11、t be agreed upon beforehand by the parties to the test.4.3.1 Total dose limit (see 1.3),4.3.2 Electrical parameters of the test device whose re-sponses are to be measured (see 10.10),4.3.3 Temperature at which the test is to be performed (see6.7),4.3.4 Details of the test circuit, including output l
12、oading,power supply levels, and other operating conditions (see 7.4and 10.3),4.3.5 Choice of radiation pulse source (see 6.9 and 7.9),4.3.6 Pulse width (see 6.9 and 7.9.2),4.3.7 Sampling (see 8.1),4.3.8 Need for total dose measurement (see 6.10, 7.8, and10.1.1),4.3.9 An irradiation plan which includ
13、es the dose rate rangeand the minimum number of dose rate values to be used in thatrange (see 10.6 and 10.9), and4.3.10 Appropriate functional test (see 10.4 and 10.8).1This practice is under the jurisdiction of ASTM Committee F01 on Electronicsand is the direct responsibility of Subcommittee F01.11
14、 on Quality and HardnessAssurance.Current edition approved June 10, 1996. Published August 1996. Originallypublished as F 773 82. Last previous edition F 773 92.2Annual Book of ASTM Standards, Vol 12.02.3Annual Book of ASTM Standards, Vol 10.04.1Copyright ASTM International, 100 Barr Harbor Drive, P
15、O Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 There are many kinds of linear integrated circuits. Anygiven linear integrated circuit may be used in a variety of waysand under various operating conditions within the limits ofperformance specified by the manufa
16、cturer. The procedures ofthis practice provide a standardized way to measure thedose-rate response of a linear integrated circuit, under operat-ing conditions similar to those of the intended application,when the circuit is exposed to pulsed ionizing radiation.5.2 Knowledge of the responses of linea
17、r integrated circuitsto radiation pulses is essential for the design, production, andmaintenance of electronic systems that are required to operatein the presence of pulsed radiation environments.6. Interferences6.1 Air IonizationA spurious component of the signalmeasured during a test can result fr
18、om conduction through airionized by the radiation pulse. Such spurious contributions canbe checked by measuring the signal while irradiating the testfixture in the absence of a test device. Air ionization contribu-tions to the observed signal are generally proportional toapplied field, while those d
19、ue to secondary emission effects(6.2) are not. The effects of air ionization external to the devicemay be minimized by coating exposed leads with a thick layerof paraffin, silicone rubber, or nonconductive enamel, or bymaking the measurement in a vacuum.6.2 Secondary Emission4Another spurious compon
20、ent ofthe measured signal can result from charge emission from, orcharge injection into, the test device and test circuit. This maybe minimized by shielding the surrounding circuitry andirradiating only the minimum area necessary to ensure irradia-tion of the test device. Reasonable estimates of the
21、 expectedmagnitude of current resulting from secondary-emission effectscan be made based on the area of metallic target materialsirradiated.NOTE 1For dose rates in excess of 108Gy (Si)/s the photocurrentsdeveloped by the package may dominate the device photocurrent. Careshould be taken in the interp
22、retation of the measured photoresponse forthese high dose rates.Values of current density per unit dose rate generally rangebetween 1011and 1010A/cm2per Gy/s. The use of a scatterplate (7.9.2) may increase these values.6.3 OrientationThe effective dose to a semiconductorjunction can be altered by ch
23、anging the orientation of the testdevice with respect to the irradiating beam. Most integratedcircuits may be considered “thin samples” (in terms of therange of the radiation). However, some devices may havecooling studs or thick-walled cases that can act to scatter theincident beam, thereby modifyi
24、ng the dose received by thesemiconductor chip. Position such devices carefully with thedie normal to the beam.6.4 Dose EnhancementHigh atomic number materialsnear the active regions of the integrated circuit (package,metallization, die attach materials, etc.) can deliver an en-hanced dose to the sen
25、sitive regions of the device when it isirradiated with an FXR. The possibility and extent of this effectshould be considered.6.5 Electrical NoiseSince radiation test facilities are in-herent sources of r-f noise, good noise-minimizing techniquessuch as singlepoint ground, filtered dc supply lines, e
26、tc., mustbe used in these measurements (see Fig. 1).4Sawyer, J. A., and van Lint, V. A. J., “Calculations of High-Energy SecondaryElectron Emission,” Journal of Applied Physics, Vol 35, No. 6, June 1964, pp.17061711.FIG. 1 Example of a Test CircuitF 773M 96 (2003)26.6 DosimetryAccurate, reproducible
27、 calibration of dose-rate monitors is difficult. For this reason, dosimetry is apt toprovide the single most substantial source of error in dose-ratedeterminations.6.7 TemperatureDevice characteristics are dependent onjunction temperature; hence, the temperature of the test shouldbe controlled. Unle
28、ss otherwise agreed upon by the parties tothe test, measurements will be made at room temperature (236 5C).6.8 Beam Homogeneity and Pulse-to-Pulse RepeatabilityThe intensity of a beam from an FXR or a LINAC is likely tovary across its cross section. Since the pulse-shape monitor isplaced at a differ
29、ent location than the device under test, themeasured dose rate may be different from the dose rate towhich the device was exposed. The spatial distribution andintensity of the beam may also vary from pulse to pulse. Thebeam homogeneity and pulse-to-pulse repeatability associatedwith a particular rad
30、iation source should be established by athorough characterization of its beam prior to performing ameasurement.6.9 Pulse WidthThe response observed in a dose rate testmay be dependent on the width of the radiation pulse. This factmust be considered when selecting a radiation source, or whencomparing
31、 data taken at different times or at different radiationtest facilities.6.10 Total DoseEach pulse of the radiation source impartsa dose to both the device under test and the device used fordosimetry. The total dose accumulated in a semiconductordevice will cause permanent damage which can change its
32、operating characteristics. As a result, the response that ismeasured after several pulses may be different from thatcharacteristic of an unirradiated device. Care should be exer-cised to ensure that the total dose delivered to the test device isless than the agreed-upon maximum value. Care must also
33、 betaken to ensure that the characteristics of the dosimeter havenot changed due to the accumulated dose.7. Apparatus7.1 Regulated DC Power Supplies with floating outputs toproduce the voltages required to bias the integrated circuitunder test.7.2 Recording Devices, such as oscilloscopes equipped wi
34、thcameras, transient digitizers with appropriate displays, or othersuitable instruments. The bandwidth capabilities of the record-ing devices shall be such that the radiation responses of theintegrated circuit and the pulse-shape monitor (7.6) are accu-rately displayed and recorded.NOTE 2Depending o
35、n the kind of measurement, dc instruments,spectrum analyzers, current transformers, or other instruments may berequired to measure and record the response of the test device.7.3 Cabling to complete adequately the connection of thetest circuit in the exposure area with the power supply andrecording d
36、evices in the data area. Shielded twisted pair orcoaxial cables may be used to connect the power supplies to thebias points of the test circuit; however, coaxial cables properlyterminated at the recording device inputs are required for thesignal leads.7.4 Test Circuit, as shown in Fig. 1. Although t
37、he details oftest circuits for this test must vary depending on the kind ofelectronic component tested and on the specific electricalparameters of the test device to be measured, the example ofFig. 1 provides the information necessary for the design of atest circuit for most purposes. The capacitor,
38、 C1(typically 10F), provides an instantaneous source of current as may berequired by the test device during the radiation pulse. Its valuemust be large enough that the decrease in the supply voltageduring a pulse is less than 10 %. Capacitor C1should beparalleled by a small (approximately 0.1 F) low
39、-inductancecapacitor, C2, to ensure that possible inductive effects of thelarge capacitor are offset. Both capacitors must be located asclose to the test device as possible, consistent with the spaceneeded for any shielding that may be necessary. The arrange-ment of the grounding connections provide
40、s that no groundloops and only one ground exists. This reduces both thepossibility of ground loops and common-mode signals presentat the terminals of the measurement instruments. The resistors,R0, are terminations for the coaxial cables, and have valueswithin 2 % of the characteristic impedances of
41、their respectivecables. All unused inputs to the test device are connected asagreed upon by the parties to the test. The output(s) of the testdevice may be loaded, as agreed upon by the parties to the test.To prevent loading of the output of the test device by thecoaxial cable, line drivers having a
42、 high input impedance andadequate bandwidth, linearity, and dynamic range may be usedto reproduce accurately at the output end of the coaxial cablethe waveforms appearing at the line driver inputs.7.5 Signal Sources, as required to provide the agreed-uponoperating conditions of the test device and t
43、o perform suitablefunctional tests.7.6 Radiation Pulse-Shape MonitorOne of the followingto develop a signal proportional to the dose rate delivered to thetest device.7.6.1 Fast Signal-Diode in the circuit configuration of Fig.2. The resistors, R1, serve as high frequency isolation and mustbe at leas
44、t 20 V. The capacitor, C1(typically 10 F), suppliesthe charge during the current transient; its value must be largeenough that the decrease in voltage during a current pulse isless than 10 %. Capacitor C1should be paralleled by a small(approximately 0.1 F) low-inductance capacitor, C2, to ensurethat
45、 possible inductive effects of the large capacitor are offset.The resistor, R0, is to provide the proper termination (within62 %) for the coaxial cable used for the signal lead. This is thepreferred apparatus for this purpose.FIG. 2 Irradiation Pulse-Shape Monitor Circuit for DiodesF 773M 96 (2003)3
46、7.6.2 P-I-N Diode in the circuit configuration of Fig. 2(7.6.1). Care should be taken to avoid saturation effects at highdose rates and R-C charging effects at low dose rates.7.6.3 Current Transformer, mounted on a collimator at theoutput window of the linear accelerator so that the primaryelectron
47、beam passes through the opening of the transformerafter passing through the collimator. The current transformermust have a bandwidth that accurately displays the currentsignal. The low frequency cutoff of some commercial currenttransformers is such that significant droop may occur for pulsewidths gr
48、eater than 1 s. Do not use a transformer for whichthis droop is greater than 5 % for the radiation pulse widthused. When monitoring large currents, do not exceed thecurrent-time saturation rating of the current transformer. It maybe required that the signal cable monitoring the currenttransformer be
49、 matched to the characteristic impedance of thetransformer; R0would then have this impedance (within62 %), as specified by the manufacturer of the current trans-former.NOTE 3Because the radiation beam from an FXR is a photon beamrather than an electron beam, a current transformer cannot be used as apulse-shape monitor with an FXR.7.6.4 Secondary-Emission Monitor consisting of a thin foil,biased negatively with respect to ground, mounted in anevacuated chamber with thin windows through which theprimary radiation beam passes after passing through a colli-ma
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