1、BRITISH STANDARDBS EN 60749-38:2008Semiconductor devices Mechanical and climatic test methods Part 38: Soft error test method for semiconductor devices with memoryICS 31.080.01g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g
2、3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 60749-38:2008This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2008 BSI 2008ISBN 978 0 580 54875 8National forewordThis British Standard is the UK impleme
3、ntation of EN 60749-38:2008. It is identical to IEC 60749-38:2008. The UK participation in its preparation was entrusted to Technical Committee EPL/47, Semiconductors.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport t
4、o include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments/corrigenda issued since publicationDate CommentsEUROPEAN STANDARD EN 60749-38 NORME EUROPENNE EUROPISCHE
5、 NORM May 2008 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2008 CENELEC - All rights of exploitation in any form and by any
6、means reserved worldwide for CENELEC members. Ref. No. EN 60749-38:2008 E ICS 31.080.01 English version Semiconductor devices - Mechanical and climatic test methods - Part 38: Soft error test method for semiconductor devices with memory (IEC 60749-38:2008) Dispositifs a semiconducteurs - Mthodes des
7、sais mcaniques et climatiques - Partie 38: Mthode dessai des erreurs logicielles pour les dispositifs semiconducteurs avec mmoire (CEI 60749-38:2008) Halbleiterbauelemente - Mechanische und klimatische Prfverfahren - Teil 38: Soft-Error-Prfverfahren fr Halbleiterbauelemente mit Speicher (IEC 60749-3
8、8:2008) This European Standard was approved by CENELEC on 2008-04-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliogr
9、aphical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility o
10、f a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, H
11、ungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Foreword The text of document 47/1943/FDIS, future edition 1 of IEC 60749-38, prepared by IEC TC 47, Semic
12、onductor devices, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60749-38 on 2008-04-01. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2009
13、-01-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2011-04-01 _ Endorsement notice The text of the International Standard IEC 60749-38:2008 was approved by CENELEC as a European Standard without any modification. _ BS EN 60749-38:2008 2 CONTENTS 1 S
14、cope.5 2 Terms and definitions .5 3 Test apparatus .7 3.1 Measurement equipment .7 3.2 Alpha radiation source.7 3.2.1 Background information.7 3.2.2 Preferred sources7 3.2.3 Variation in results.7 3.2.4 Effect of high radiation levels.7 3.2.5 Measurement accuracy8 3.3 Test sample 8 4 Procedure 8 4.1
15、 Alpha radiation accelerated soft error test .8 4.1.1 Surface preparation .8 4.1.2 Power supply voltage 8 4.1.3 Ambient temperature .9 4.1.4 Core cycle time9 4.1.5 Data pattern 9 4.1.6 Distance between chip and radiation source 9 4.1.7 Number of measurement samples9 4.2 Real-time soft error test.9 4
16、.2.1 General .9 4.2.2 Power supply voltage 9 4.2.3 Ambient temperature .9 4.2.4 Operating frequency 9 4.2.5 Data pattern 10 4.2.6 Test time .10 4.2.7 Number of test samples.10 4.2.8 Environmental neutron testing .10 4.3 Neutron radiation accelerated soft error test10 5 Evaluation 10 5.1 Alpha radiat
17、ion accelerated soft error test .10 5.2 Real-time soft error test.11 6 Summary12 Bibliography13 Figure 1 Effect of source-device spacing on normalized flux at device .8 Table 1 X for FIT calculation 11 BS EN 60749-38:2008 3 blank 4 SEMICONDUCTOR DEVICES MECHANICAL AND CLIMATIC TEST METHODS Part 38:
18、Soft error test method for semiconductor devices with memory 1 Scope This part of IEC 60749 establishes a procedure for measuring the soft error susceptibility of semiconductor devices with memory when subjected to energetic particles such as alpha radiation. Two tests are described; an accelerated
19、test using an alpha radiation source and an (unaccelerated) real-time system test where any errors are generated under conditions of naturally occurring radiation which can be alpha or other radiation such as neutron. To completely characterize the soft error capability of an integrated circuit with
20、 memory, the device must be tested for broad high energy spectrum and thermal neutrons using additional test methods. This test method may be applied to any type of integrated circuit with memory device. 2 Terms and definitions For the purposes of this document, the following terms and definitions a
21、pply. 2.1 single-event upset SEU soft error caused by the transient signal induced by a single energetic-particle strike 2.2 soft error erroneous output signal from a latch or memory cell that can be corrected by performing one or more normal functions of the device containing the latch or memory ce
22、ll NOTE As commonly used, the term refers to an error caused by radiation or electromagnetic pulses and not to an error associated with a physical defect introduced during the manufacturing process. 2.3 single-event hard error SHE irreversible change in operation resulting from a single radiation ev
23、ent and typically associated with permanent damage to one or more of the device elements (e.g. gate oxide rupture) 2.4 static soft error soft error that is not corrected by repeated reading but can be corrected by rewriting without the removal of power 2.5 transient soft error soft error that can be
24、 corrected by repeated reading without rewriting and without the removal of power BS EN 60749-38:2008 5 2.6 soft error, power cycle PCSE soft error that is not corrected by repeated reading or writing but can be corrected by the removal of power 2.7 single event functional interrupt SEFI soft error
25、that causes the component to reset, lock-up, or otherwise malfunction in a detectable way, but does not require power cycling of the device (off and back on) to restore operability, unlike single-event latch-up (SEL), or result in permanent damage as in single-event burnout (SEB) 2.8 multiple bit up
26、set MBU multiple-cell upset in which two or more error bits occur in the same word 2.9 single event latch up SEL abnormal high-current state in a device caused by the passage of a single energetic particle through sensitive regions of the device structure and resulting in the loss of device function
27、ality NOTE 1 SEL may cause permanent damage to the device. If the device is not permanently damaged, power cycling of the device (off and back on) is necessary to restore normal operation. NOTE 2 An example of SEL in a CMOS device is when the passage of a single particle induces the creation of para
28、sitic bipolar (p-n-p-n) shorting of power to ground. 2.10 flux (of particle radiation) time rate of flow of particles emitted from or incident on a surface, divided by the area of that surface NOTE The flux is usually expressed in particles per square centimeter second (N/cm2s) or particles per squa
29、re centimeter hour (N/cm2h). 2.11 alpha source activity number of alpha particle decays in the alpha source per unit time NOTE The preferred SI unit is the Becquerel (Bq); to convert from the Curie, multiply by 3,7 1010(exactly). 2.12 soft error rate SER rate at which soft errors occur 2.13 failures
30、 in time FIT the number of failures in 109device-hours 2.14 multiple-cell upset MCU single event that induces several bits in an IC to have a soft error at one time BS EN 60749-38:2008 6 NOTE The bits are usually, but not always, adjacent. 3 Test apparatus 3.1 Measurement equipment The equipment sha
31、ll be capable of measuring the functions of the integrated circuit devices, and capable of measuring the time taken for the change of stored data by the exposure to energetic particles, such as alpha radiation to take place (i.e. the generation of a soft error). Alternatively, the test equipment (me
32、mory tester etc.) shall have the capability of counting the number of soft errors in unit time. 3.2 Alpha radiation source 3.2.1 Background information Uranium and thorium impurities found in trace amounts in the various production and packaging materials emit alpha particles. Alpha particles are st
33、rongly ionizing, so those that impinge on the active device create bursts of free electron-hole pairs in the silicon. Different types of alpha sources can be used to simulate the alpha emission from uranium and thorium impurities. Sources that emit alpha particles with energy spectra similar to uran
34、ium and thorium impurities simulate the radiation environment of wirebonded components encapsulated in moulding compound. Sources that emit alpha particles with similar energy spectra to 210Po are used for simulating components in a flip-chip arrangement with solder bumps. The source should provide
35、an alpha particle spectrum similar to that encountered in the actual component. 3.2.2 Preferred sources 238U or 232Th are the preferred sources for inducing SER in mould-resin compounds. 241Am and 210Po sources can be used as substitutes. 3.2.3 Variation in results Results will differ depending on t
36、he source used due to spectral variations. Alpha particle sources available on the market are usually only classified by their activities in Ci (rather than in the preferred unit, Bq, see 2.11) and the emission rates of alpha particle are seldom indicated. The emission rate cannot be determined simp
37、ly from the activities because of the effects of absorption of alpha particle in the source itself and its situation. For example, the activity of 1Ci is 3,7 104decays/s. However, the alpha emission rate from the source would be less than 3,7 104alpha/s. Therefore, a measurement of the alpha emissio
38、n rate of the source which is used in the SER test is recommended. As a consequence, the energy spectrum of the alpha radiation source shall be confirmed because different test values can result from differing energy spectra even if the alpha radiation sources have the same level of radioactivity. N
39、OTE If 241Am or 210Po are used, this should be documented in a report along with the statement that results can differ if other sources have been used, due to energy spectra variations. 3.2.4 Effect of high radiation levels In cases where the dose concentration delivered to the test sample is high,
40、consideration shall be given to the effect of multiple hits. BS EN 60749-38:2008 7 3.2.5 Measurement accuracy If the emission area of the alpha radiation is significantly smaller than the chip area, absorption of the alpha radiation through the atmosphere and the chip protection film and incident an
41、gle effects will contribute to give erroneous values. Therefore, to perform the test accurately, the emission area of the alpha radiation shall not be significantly smaller than the chip area and, preferably, shall be larger. In Figure 1, the curves apply for devices of about 10 mm diameter. Dimensi
42、on “d“ should be scaled up or down in proportion for devices with a different diameter (for more information, see Bibliography). 0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 0 1 2345678910Source-device spacing (mm)ddMedium sourceLarge sourcePoint sourceNormalized fluxat deviceIEC 202/08 Figure 1 Effe
43、ct of source-device spacing on normalized flux at device 3.3 Test sample Any type of integrated circuits with memory may be tested. The device parameters (capacitance of the memory cell in the DRAM etc.) which can affect the soft error rate shall be well understood. 4 Procedure 4.1 Alpha radiation a
44、ccelerated soft error test 4.1.1 Surface preparation The surface of the sample shall be suitably prepared before irradiation. For accelerated alpha particle testing, the surface of the sample shall be exposed using a method which does not affect the electrical characteristics. When, however, the pur
45、pose of the test is to evaluate the effect of chip coating, the chip coating shall not be removed. NOTE As an example, the upper side of the package can be cut with a small knife or the moulding resin on the upper surface of the chip can be dissolved chemically etc. Unless otherwise specified, chip
46、coatings should be removed because alpha radiation from an 241Am source (peak energy 5 MeV approximately) is absorbed by the chip coating. Alpha radiation of higher energy can occur in the package materials or as natural radio-activity. 4.1.2 Power supply voltage This shall be set at the minimum vol
47、tage of the recommended operating condition (when required, the supply voltage dependence on failure rate shall be measured). For latch up testing, the voltage shall be set at the minimum and maximum voltage of the recommended operating condition. BS EN 60749-38:2008 8 4.1.3 Ambient temperature The
48、ambient temperature shall be room temperature and, for latch up, at the manufacturers maximum recommended operating temperature. 4.1.4 Core cycle time The core cycle time is dependent on the samples under test and shall be set to the manufacturers recommended value (when required, the core cycle tim
49、e dependence shall be measured). 4.1.5 Data pattern This is dependent on the samples under test. Data pattern shall be reported (a checker board, all 0/1-read/write pattern, etc.). 4.1.6 Distance between chip and radiation source The actual value used shall be documented in the report. NOTE The distance between the chip and radiation source should be 1 mm or less. Excessive distance between the source and the chip will cause attenuation of the alpha flux, unless the test is performed in a vacuum. Operators shoul
