1、JEDEC PUBLICATION Failure Mechanisms and Models for Semiconductor Devices JEP122G (Revision of JEP122F, November 2010) OCTOBER 2011 JEDEC SOLID STATE TECHNOLOGY ASSOCIATION NOTICE JEDEC standards and publications contain material that has been prepared, reviewed, and approved through the JEDEC Board
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10、ion No. 122G FAILURE MECHANISMS AND MODELS FOR SEMICONDUCTOR DEVICES Contents Page Foreword iii Introduction iii 1 Scope 1 2 Terms and definitions 1 3 Inclusions, deliberate omissions, and resources 5 4 The basic thermal acceleration equation 9 5 Models for common failure mechanisms 9 FEoL Failure M
11、echanisms 5.1 Time-Dependent Dielectric Breakdown (TDDB) gate oxide 9 5.2 Hot Carrier Injection (HCI) 14 5.3 Negative Bias Temperature Instability (NBTI) 17 5.4 Surface inversion (mobile ions) 20 5.5 Floating-Gate Nonvolatile Memory Data Retention 22 5.6 Localized Charge Trapping Nonvolatile Memory
12、Data Retention 26 5.7 Phase Change (PCM) Nonvolatile Memory Data Retention 27 BEoL Failure Mechanisms 5.8 Time-Dependent Dielectric Breakdown (TDDB) ILD/Low-k/Mobile Cu ion 30 5.9 Aluminum Electromigration (Al EM) 38 5.10 Copper Electromigration (Cu EM) 41 5.11 Aluminum and Copper Corrosion 43 5.12
13、Aluminum Stress Migration (Al SM) 48 5.13 Copper Stress Migration (Cu SM) 50 Packaging/Interfacial Failure Mechanisms 5.14 Fatigue failure due to temperature cycling and thermal shock 53 5.15 Interfacial failure due to temperature cycling and thermal shock 57 5.16 Intermetallic and oxidation failure
14、 due to high temperature 60 5.17 Tin Whiskers 62 5.18 Ionic Mobility Kinetics (PCB) Component Cleanliness 66 Statistics and Modeling Parameter Determination 5.19 Reliability data/analysis 69 5.20 Design of Experiments (DOE) for determination of modeling parameters 74 6 Activation energies and modeli
15、ng factors 76 Annexes Annex A List of references 81 Annex B Differences between JEP122G and JEP122F 96 -i- JEDEC Publication No. 122G -ii- FAILURE MECHANISMS AND MODELS FOR SEMICONDUCTOR DEVICES Contents Page Figures 5.1.1 Photograph of TDDB breakdown in a gate oxide mid-gate 13 5.5.1 Extrapolation
16、of SILC bit error rate 25 5.8.1 Time-Dependent Dielectric Breakdown (TDDB) in various dielectrics 30 5.8.2 Metal stack cross section/schematic 32 5.8.3 Normal distribution of breakdown voltage 33 5.8.4 Copper short/extrusion 34 5.9.1 Examples of Aluminum Electromigration 40 5.10.1 Examples of Copper
17、 Electromigration 43 5.11.1 Aluminum bond pad corrosion 47 5.11.2 Electrochemical reaction 47 5.11.3 Corrosion rate versus surface mobility 47 5.12.1 Examples of Aluminum Stress Migration 50 5.13.1 Examples of Copper Stress Migration 53 5.14.1 Examples of temperature cycling/thermal shock damage 57
18、5.15.1 Example of interfacial delamination after temperature cycling 60 5.17.1 SEM of Tin Whiskers on Matte Tin plated Alloy 42 leads 5.16.4 64 5.17.2 Optical Image of a Tin Whisker growing from Relay lead to case 5.16.3 64 5.17.3 FIB - matte tin whisker structure from a temperature cycled specimen
19、5.16.5 65 5.17.4 Optical Image - Tin Whisker growing from SAC 305 solder over Alloy 42 - matte tin 65 5.17.5 Optical image of Tin Whisker on a copper coupon with matte tin plating 5.16.4 65 5.17.6 8 mm long Tin Whisker growing from a bracket holding electronics in a frame. 65 5.17.7 Tin Whisker brea
20、king through 10 m Uralane 5750 coating (9 yr office storage) 5.16.3 65 5.18.1 Resistor corroded open due to trapped MSA residues in epoxy surface 3 67 5.18.2 Electrochemical migration between leads on a QFP 67 5.18.3 Leakage and corrosion problems with residues on tinned leads due to aggressive flux
21、 68 5.18.4 Leakage square brackets enclose citation numbers. All equation, citation, and figure numbers include the subclause number so that individual clauses can be modified without disturbing other clauses, except for page numbers. Thus, (5.3.2) is the 2nd equation in 5.3 and 5.11.5 is the 5th ci
22、tation in 5.11. The citations can be found in Annex A. -iii- JEDEC Publication No. 122G -iv- JEDEC Publication No. 122G Page 1 FAILURE MECHANISMS AND MODELS FOR SEMICONDUCTOR DEVICES (From JEDEC Board Ballot JCB-01-97, JCB-03-39, JCB-08-61, JCB-09-19, JCB-10-64, and JCB-11-74 formulated under the co
23、gnizance of JC-14.1 Subcommittee on Reliability Test Methods for Packaged Devices.) 1 Scope This publication provides a list of failure mechanisms and their associated activation energies or acceleration factors that may be used in making system failure rate estimations when the only available data
24、is based on tests performed at accelerated stress test conditions. The method to be used is the Sum-of-the-Failure-Rates method. The models apply primarily to the following: a) Aluminum (doped with small amounts of Cu and/or Si) and copper alloy metallization b) Refractory metal barrier metals with
25、thin anti-reflection coatings c) Doped silica or silicon nitride interlayer dielectrics, including low dielectric constant materials d) Poly silicon or “salicide” gates (metal-rich silicides such as W, Ni k is Boltzmanns constant (8.62 105eV/K); T1is the absolute temperature of test 1 (K); T2is the
26、absolute temperature of test 2 (K); T1is the observed failure rate at test temperature T1 (h-1); T2is the observed failure rate at test temperature T2 (h-1). NOTE 2 The best-fit linear slope of a plot of the natural log of the time-to-failure as a function of 1/kT, the reciprocal of the product of B
27、oltzmanns constant in electronvolts per kelvin and the absolute temperature in kelvins, is equal to the apparent activation energy in electronvolts. NOTE 3 q= o . AT, where qis the quoted (predicted) system failure rate at some system temperature Ts, ois the observed failure rate at some test temper
28、ature Tt, and ATis the temperature acceleration factor from Ttto Ts. activation energy (Ea): The excess free energy over the ground state that must be acquired by an atomic or molecular system in order that a particular process can occur. NOTE The activation energy is used in the Arrhenius equation
29、for the thermal acceleration of physical reactions. The term “activation energy” is not applicable when describing thermal acceleration of time-to-failure distributions, e.g., in the Arrhenius equation for reliability; hence the need for the term “apparent activation energy”. apparent activation ene
30、rgy (Eaa): An energy value, analogous to activation energy, that can be inserted in the Arrhenius equation for reliability to calculate an acceleration factor applicable to changes with temperature of time-to-failure distributions. NOTE 1 An apparent activation energy should be associated with a spe
31、cific failure mechanism and an observed time-to-failure distribution to calculate the acceleration factor for converting the observed failure rate to the quoted failure rate at a different temperature. NOTE 2 An activation energy is a measure of the heat energy needed to establish the rate of reacti
32、on for a specific failure mechanism. The reaction rate and other contributing factors, e.g., radiation, voltage, humidity, magnetic fields, determine the unique time-to-failure distribution for the modeled failure mechanism. NOTE 3 The apparent activation energy is empirically determined from the ch
33、ange in an observed time-to-failure distribution with temperature. bathtub curve: A plot of failure rate versus time or cycles that exhibits three phases of life: infant mortality (decreasing failure rate), intrinsic or useful life (relatively constant failure rate), and wear-out (increasing failure
34、 rate). Boltzmanns constant (k): A constant equal to 1.38 x 1023joule per kelvin or 8.62 x 105electronvolt per kelvin. JEDEC Publication No. 122G Page 3 2 Terms and definitions (contd) cumulative distribution function of the time-to-failure; cumulative mortality function F(t): The probability that a
35、 device will have failed by a specified time t1,or the fraction of units that have failed by that time. NOTE 1 The value of this function is given by the integral of f(t) from t = 0 to t = t1 and is generally expressed in percent (%) or in parts per million (ppm) for a defined early-life failure per
36、iod. See “probability density functionof the time-to-failure” for f(t). NOTE 2 The abbreviation CDF is often used; however, the symbol F(t) is preferred. cumulative hazard function H(t): The fraction of units that have failed referenced to the survivors (not to the initial number of units). NOTE The
37、 value of this function at a specified time t1 is given by the integral of h(t) from t = 0 to t = t1.See “instantaneous failure rate; hazard rate” for h(t). cumulative reliability function R(t): The probability that a device will still be functional at a specified time t1,or the fraction of units su
38、rviving to that time. NOTE R(t) = 1 F(t). See “cumulative distribution function of the time-to-failure” for F(t). failure mechanism: The physical, chemical, electrical, or other process that has led to a nonconformance. NOTE 1 See JESD671, Component Quality Problem Analysis and Corrective Action Req
39、uirements. NOTE 2 A failure mechanism may be characterized by how a degradation process proceeds including the driving force, e.g., oxidation, diffusion, electric field, current density. When the driving force is known, a mechanism may be described by an explicit failure rate model; identifying that
40、 model with associated parameters is the main objective of this document. failure mode: (general) The way in which a failure mechanism manifests itself in a failing component. NOTE 1 Examples of failure modes are a visual blemish, a bent lead, a foreign particle or material, an incorrect dopant prof
41、ile or grain size, a scratch, an electrical fault (open, short, leakage, inadequate slew rate or noise margin, stuck at high or low, etc.). NOTE 2 Failure rate distributions for a given failure mode can be modeled only when the failure mechanism and the relevant independent variables (forcing functi
42、ons) are known. failure rate (): The fraction of a population that fails within a specified interval, divided by that interval. NOTE 1 Standard methods of reporting failure rates of semiconductor devices include 1) percent failed per 1000 hours and 2) FITs. NOTE 2 The interval may be expressed in op
43、erating hours, storage hours, operating cycles, or other units of interval measurement. NOTE 3 Typically, the term “failure rate” means the instantaneous failure (hazard) rate. NOTE 4 The statistical upper limit estimate of the failure rate is usually calculated using the (chi-squared) function. fai
44、lures in time (FITs): The number of failures per 109device hours. JEDEC Publication No. 122G Page 4 2 Terms and definitions (contd) instantaneous failure rate; hazard rate h(t): The rate at which devices are failing referenced to the survivors (not to the initial number of units). NOTE h(t) = f(t)/R
45、(t). See “probability density function of the time-to-failure” for f(t) and “cumulative reliability function” for R(t). mean-time-between-failures (MTBF): The average time between failures in repairable or redundant systems. mean-time-to-failure (MTTF): The average time to failure for components or
46、nonrepairable systems. NOTE The MTTF is often the reciprocal of the hazard rate when the hazard rate is described by the Poisson or equivalent exponential function, e.g., in the constant or flat portion of the useful life region of the bathtub curve. whisker: A spontaneous columnar or cylindrical fi
47、lament, usually of monocrystalline metal, emanating from the surface of a finish. NOTE Whiskers are not to be confused with dendrites, which are fern-like growths on the surface of a material, formed as a result of electromigration of an ionic species or during solidification. observed failure rate:
48、 The failure rate determined from a product or test vehicle subjected to an accelerating stress that may produce failures attributable to one or more failure mechanisms. PCB component cleanliness: The absence of chemical residues, on or in the surface of components on printed circuit boards, that re
49、sult from their processing and handling. NOTE These residues may react with the environmental moisture or processing conditions and have either positive or negative impact on product performance. planning activation energy (Eap): A psuedo apparent activation energy, derived from Pareto analysis and experience, using the principles of the physical relationship between stress and failure rate. NOTE 1 Eapcan be used to estimate sample sizes and test times. NOTE 2 Th
