Reliability of semiconductor devices can be summarized as follows: #

Semiconductor A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way ...

devices are very sensitive to impurities and particles. Therefore, to manufacture these devices it is necessary to manage many processes while accurately controlling the level of impurities and particles. The finished product quality depends upon the many layered relationship of each interacting substance in the semiconductor, including metallization, chip material (

list of semiconductor materials Semiconductor materials are nominally small band gap insulators. The defining property of a semiconductor material is that it can be compromised by doping it with impurities that alter its electronic properties in a controllable way. Because of ...

) and package. # The problems of micro-processes, and

thin films A thin film is a layer of material ranging from fractions of a nanometer ( monolayer) to several micrometers in thickness. The controlled synthesis of materials as thin films (a process referred to as deposition) is a fundamental step in many ...

and must be fully understood as they apply to metallization and

wire bonding Wire bonding is the method of making interconnections between an integrated circuit (IC) or other semiconductor device and its packaging during semiconductor device fabrication. Although less common, wire bonding can be used to connect an IC ...

. It is also necessary to analyze surface phenomena from the aspect of thin films. # Due to the rapid advances in technology, many new devices are developed using new materials and processes, and design calendar time is limited due to

non-recurring engineering Non-recurring engineering (NRE) cost refers to the one-time cost to research, design, develop and test a new product or product enhancement. When budgeting for a new product, NRE must be considered to analyze if a new product will be profitable. ...

constraints, plus time to market concerns. Consequently, it is not possible to base new designs on the reliability of existing devices. # To achieve

economy of scale In microeconomics, economies of scale are the cost advantages that enterprises obtain due to their scale of operation, and are typically measured by the amount of output produced per unit of time. A decrease in cost per unit of output enables a ...

, semiconductor products are manufactured in high volume. Furthermore, repair of finished semiconductor products is impractical. Therefore, incorporation of reliability at the design stage and reduction of variation in the production stage have become essential. # Reliability of semiconductor devices may depend on assembly, use, environmental, and cooling conditions. Stress factors affecting device reliability include gas,

dust Dust is made of fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind (an aeolian process), volcanic eruptions, and pollution. Dust in ...

, contamination,

voltage Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to ...

current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (stre ...

density,

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...

humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity dep ...

mechanical stress In continuum mechanics, stress is a physical quantity. It is a quantity that describes the magnitude of forces that cause deformation. Stress is defined as ''force per unit area''. When an object is pulled apart by a force it will cause elonga ...

vibration Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic, such as the motion of a pendulum—or random, su ...

shock Shock may refer to: Common uses Collective noun *Shock, a historic commercial term for a group of 60, see English numerals#Special names * Stook, or shock of grain, stacked sheaves Healthcare * Shock (circulatory), circulatory medical emerge ...

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: * ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visi ...

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country a ...

, and intensity of

magnetic Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particl ...

and

electrical Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...

fields. Design factors affecting semiconductor reliability include:

power Power most often refers to: * Power (physics), meaning "rate of doing work" ** Engine power, the power put out by an engine ** Electric power * Power (social and political), the ability to influence people or events ** Abusive power Power may a ...

, and

derating In electronics, derating (or derating) is the operation of a device at less than its rated maximum capability to prolong its life. Typical examples include operations below the maximum power rating, current rating, or voltage rating. In electron ...

;

metastability In chemistry and physics, metastability denotes an intermediate energetic state within a dynamical system other than the system's state of least energy. A ball resting in a hollow on a slope is a simple example of metastability. If the ball i ...

; logic timing margins (

logic simulation Logic simulation is the use of simulation software to predict the behavior of digital circuits and hardware description languages. Simulation can be performed at varying degrees of physical abstraction, such as at the transistor level, gate ...

); timing analysis;

derating; and

process control An industrial process control in continuous production processes is a discipline that uses industrial control systems to achieve a production level of consistency, economy and safety which could not be achieved purely by human manual control. ...

Methods of improvement

Reliability of semiconductors is kept high through several methods.

Cleanrooms A cleanroom or clean room is an engineered space, which maintains a very low concentration of airborne particulates. It is well isolated, well-controlled from contamination, and actively cleansed. Such rooms are commonly needed for scientif ...

control impurities,

controls processing, and

burn-in Burn-in is the process by which components of a system are exercised before being placed in service (and often, before the system being completely assembled from those components). This testing process will force certain failures to occur under ...

(short term operation at extremes) and probe and test reduce escapes. Probe (

wafer prober A wafer is a crisp, often sweet, very thin, flat, light and dry biscuit, often used to decorate ice cream, and also used as a garnish on some sweet dishes. Wafers can also be made into cookies with cream flavoring sandwiched between them. They ...

) tests the semiconductor die, prior to packaging, via micro-probes connected to test equipment. Final test tests the packaged device, often pre-, and post burn-in for a set of parameters that assure operation. Process and design weaknesses are identified by applying a set of stress tests in the qualification phase of the semiconductors before their market introduction e. g. according to the AEC Q100 and Q101 stress qualifications.AEC Documents
/ref> Parts Average Testing is a statistical method for recognizing and quarantining semiconductor die that have a higher probability of reliability failures. This technique identifies characteristics that are within specification but outside of a normal distribution for that population as at-risk outliers not suitable for high reliability applications. Tester-based Parts Average Testing varieties include Parametric Parts Average Testing (P-PAT) and Geographical Parts Average Testing (G-PAT), among others. Inline Parts Average Testing (I-PAT) uses data from production process control inspection and metrology to perform the outlier recognition function. Bond strength measurement is performed in two basic types: pull testing and shear testing. Both can be done destructively, which is more common, or non destructively. Non destructive tests are normally used when extreme reliability is required such as in military or aerospace applications.

Failure mechanisms

Failure mechanisms of electronic semiconductor devices fall in the following categories # Material-interaction-induced mechanisms. # Stress-induced mechanisms. # Mechanically induced failure mechanisms. # Environmentally induced failure mechanisms.

Material-interaction-induced mechanisms

Field-effect transistor The field-effect transistor (FET) is a type of transistor that uses an electric field to control the flow of current in a semiconductor. FETs (JFETs or MOSFETs) are devices with three terminals: ''source'', ''gate'', and ''drain''. FETs co ...

gate-metal sinking #

Ohmic contact An ohmic contact is a non-rectifying electrical junction: a junction between two conductors that has a linear current–voltage (I–V) curve as with Ohm's law. Low-resistance ohmic contacts are used to allow charge to flow easily in both direct ...

degradation # Channel degradation # Surface-state effects # Package molding contamination—impurities in packaging compounds cause electrical failure

Stress-induced failure mechanisms

Electromigration Electromigration is the transport of material caused by the gradual movement of the ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms. The effect is important in applications where high dir ...

– electrically induced movement of the materials in the chip # Burnout – localized overstress # Hot Electron Trapping – due to overdrive in power RF circuits # Electrical Stress –

Electrostatic discharge Electrostatic discharge (ESD) is a sudden and momentary flow of electric current between two electrically charged objects caused by contact, an electrical short or dielectric breakdown. A buildup of static electricity can be caused by tribochar ...

, High Electro-Magnetic Fields ( HIRF),

Latch-up A latch-up is a type of short circuit which can occur in an integrated circuit (IC). More specifically it is the inadvertent creation of a low- impedance path between the power supply rails of a MOSFET circuit, triggering a parasitic structure wh ...

overvoltage When the voltage in a circuit or part of it is raised above its upper design limit, this is known as overvoltage. The conditions may be hazardous. Depending on its duration, the overvoltage event can be transient—a voltage spike—or per ...

overcurrent In an electric power system, overcurrent or excess current is a situation where a larger than intended electric current exists through a conductor, leading to excessive generation of heat, and the risk of fire or damage to equipment. Possible caus ...

Mechanically induced failure mechanisms

# Die

fracture Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displ ...

– due to mis-match of thermal expansion coefficients # Die-attach

voids Void may refer to: Science, engineering, and technology * Void (astronomy), the spaces between galaxy filaments that contain no galaxies * Void (composites), a pore that remains unoccupied in a composite material * Void, synonym for vacuum, a s ...

– manufacturing defect—screenable with Scanning Acoustic Microscopy. # Solder joint failure by creep fatigue or intermetallics cracks. # Die-pad/molding compound delamination due to thermal cycling

Environmentally induced failure mechanisms

# Humidity effects – moisture absorption by the package and circuit # Hydrogen effects – Hydrogen induced breakdown of portions of the circuit (Metal) # Other Temperature Effects—Accelerated Aging, Increased Electro-migration with temperature, Increased Burn-Out

References

Bibliography

* * * MIL-HDBK-217F Reliability Prediction of Electronic Equipment * MIL-HDBK-251 Reliability/Design Thermal Applications * MIL-HDBK-H 108 Sampling Procedures and Tables for Life and Reliability Testing (Based on Exponential Distribution) * MIL-HDBK-338 Electronic Reliability Design Handbook * MIL-HDBK-344 Environmental Stress Screening of Electronic Equipment * MIL-STD-690C Failure Rate Sampling Plans and Procedures * MIL-STD-721C Definition of Terms for Reliability and Maintainability * MIL-STD-756B Reliability Modeling and Prediction * MIL-HDBK-781 Reliability Test Methods, Plans and Environments for Engineering Development, Qualification and Production * MIL-STD-1543B Reliability Program Requirements for Space and Missile Systems * MIL-STD-1629A Procedures for Performing a Failure Mode, Effects, and Criticality Analysis * MIL-STD-1686B Electrostatic Discharge Control Program for Protection of Electrical and Electronic Parts, Assemblies and Equipment (Excluding Electrically Initiated Explosive Devices) * MIL-STD-2074 Failure Classification for Reliability Testing * MIL-STD-2164 Environment Stress Screening Process for Electronic Equipment * * * * * {{cite journal , last1=Akbari , first1=M. , last2=Bahman , first2=A.S. , last3=Reigosa , first3=P.D. , last4=Iannuzzo , first4=F. , last5=Bina , first5=M.T. , title=Thermal modeling of wire-bonded power modules considering non-uniform temperature and electric current interactions , journal=Microelectronics Reliability , date=September 2018 , volume=88-90 , pages=1135–1140 , doi=10.1016/j.microrel.2018.07.150 , s2cid=53529098 , url=https://vbn.aau.dk/da/publications/81f0ae92-f0e2-4608-88a7-6a7c17ae8375 Semiconductor device fabrication