Reliability of semiconductor devices can be summarized as follows:

1. Semiconductor
   Semiconductor
   A semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...
   
    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
   Material
   Material is anything made of matter, constituted of one or more substances. Wood, cement, hydrogen, air and water are all examples of materials. Sometimes the term "material" is used more narrowly to refer to substances or components with certain physical properties that are used as inputs to...
   
    (list of semiconductor materials) and package.
2. The problems of micro-processes, and thin films and must be fully understood as they apply to metallization and bonding wire bonding
   Wire bonding
   Wire bonding is the primary method of making interconnections between an integrated circuit and a printed circuit board during semiconductor device fabrication. Although less common, wire bonding can be used to connect an IC to other electronics or to connect from one PCB to another...
   
   . It is also necessary to analyze surface phenomena from the aspect of thin films.
3. 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
   Non-recurring engineering refers to the one-time cost to research, develop, design and test a new product. When budgeting for a project, NRE must be considered to analyze if a new product will be profitable...
   
    constraints, plus time to market
   Time to market
   In commerce, time to market is the length of time it takes from a product being conceived until its being available for sale. TTM is important in industries where products are outmoded quickly...
   
    concerns. Consequently, it is not possible to base new designs on the reliability of existing devices.
4. To achieve economy of scale, 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.
5. Reliability of semiconductor devices may depend on assembly, use, and environmental conditions. Stress factors effecting device reliability include gas
   Gas
   Gas is one of the three classical states of matter . Near absolute zero, a substance exists as a solid. As heat is added to this substance it melts into a liquid at its melting point , boils into a gas at its boiling point, and if heated high enough would enter a plasma state in which the electrons...
   
   , dust
   Dust
   Dust consists of particles in the atmosphere that arise from various sources such as soil dust lifted up by wind , volcanic eruptions, and pollution...
   
   , contamination, voltage
   Voltage
   Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
   
   , current
   Electric current
   Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
   
    density, temperature
   Temperature
   Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
   
   , humidity
   Humidity
   Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...
   
   , mechanical stress, vibration
   Vibration
   Vibration refers to mechanical oscillations about an equilibrium point. The oscillations may be periodic such as the motion of a pendulum or random such as the movement of a tire on a gravel road.Vibration is occasionally "desirable"...
   
   , shock
   Shock (mechanics)
   A mechanical or physical shock is a sudden acceleration or deceleration caused, for example, by impact, drop, kick, earthquake, or explosion. Shock is a transient physical excitation....
   
   , radiation
   Radiation
   In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
   
   , pressure
   Pressure
   Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
   
   , and intensity of magnetic and electrical fields.

Design factors affecting semiconductor reliability include: voltage

Voltage

Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...

 derating, power

Electric power

Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...

 derating, current

Electric current

Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...

 derating, metastability

Metastability

Metastability describes the extended duration of certain equilibria acquired by complex systems when leaving their most stable state after an external action....

, logic timing margins (logic simulation

Logic simulation

Logic simulation is the use of a computer program to simulate the operation of a digital circuit. Logic simulation is the primary tool used for verifying the logical correctness of a hardware design. In many cases logic simulation is the first activity performed in the process of taking a hardware...

), timing analysis, temperature

Temperature

Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

 derating, and process control

Process control

Process control is a statistics and engineering discipline that deals with architectures, mechanisms and algorithms for maintaining the output of a specific process within a desired range...

.

Methods of improvement

Reliability of semiconductors is kept high through several methods. Cleanrooms control impurities,
process control

Process control

Process control is a statistics and engineering discipline that deals with architectures, mechanisms and algorithms for maintaining the output of a specific process within a desired range...

 controls processing, and burn-in (short term operation at extremes) and probe and test reduce escapes. Probe (wafer prober) tests the semiconductor die, prior to packaging, via micro-probes connected to test equipment. Wafer testing

Wafer testing

Wafer testing is a step performed during semiconductor device fabrication. During this step, performed before a wafer is sent to die preparation, all individual integrated circuits that are present on the wafer are tested for functional defects by applying special test patterns to them. The wafer...

 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

Automotive Electronics Council

The Automotive Electronics Council is an organisation based in the USA that sets qualification standards for the supply of components in the automotive electronics industry.- See also :* Body electronics* Car audio* Carputer* Chassis electronics...

 Q100 and Q101 stress qualifications.

Failure mechanisms

Failure mechanisms of electronic semiconductor devices fall in the following categories

1. Material-interaction-induced mechanisms.
2. Stress-induced mechanisms.
3. Mechanically induced failure mechanisms.
4. Environmentally induced failure mechanisms.

Material-interaction-induced mechanisms

1. Field-effect transistor
   Field-effect transistor
   The field-effect transistor is a transistor that relies on an electric field to control the shape and hence the conductivity of a channel of one type of charge carrier in a semiconductor material. FETs are sometimes called unipolar transistors to contrast their single-carrier-type operation with...
   
    gate-metal sinking
2. Ohmic contact
   Ohmic contact
   An ohmic contact is a region on a semiconductor device that has been prepared so that the current-voltage curve of the device is linear and symmetric. If the I-V characteristic is non-linear and asymmetric, the contact is not ohmic, but is a blocking or Schottky contact...
   
    degradation
3. Channel degradation
4. Surface-state effects
5. Package molding contamination—impurities in packaging compounds cause electrical failure

Stress-induced failure mechanisms

1. Electromigration
   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 direct current densities are used, such as in...
   
    – electrically induced movement of the materials in the chip
2. Burnout – localized overstress
3. Hot Electron Trapping – due to overdrive in power RF circuits
4. Electrical Stress – Electrostatic discharge
   Electrostatic discharge
   Electrostatic discharge is a serious issue in solid state electronics, such as integrated circuits. Integrated circuits are made from semiconductor materials such as silicon and insulating materials such as silicon dioxide...
   
   , High Electro-Magnetic Fields (HIRF
   HIRF
   HIRF is an acronym for High Intensity Radiated Fields and refers to radio frequency energy of a strength sufficient to cause adversely effect either the performance of a device subjected to it, or to a living organism. A microwave oven is an example of this principle put to controlled, safe...
   
   ), Latch-up overvoltage
   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...
   
   , overcurrent
   Overcurrent
   In electricity supply, 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 causes for overcurrent include short circuits, excessive load,...
   
   

Mechanically induced failure mechanisms

1. Die fracture
   Fracture
   A fracture is the separation of an object or material into two, or more, pieces under the action of stress.The word fracture is often applied to bones of living creatures , or to crystals or crystalline materials, such as gemstones or metal...
   
    – due to mis-match of thermal expansion coefficients
2. Die-attach voids – manufacturing defect—screenable with Scanning Acoustic Microscopy.
3. Solder joint failure by creep fatigue or intermetallics cracks.

Environmentally induced failure mechanisms

1. Humidity effects – moisture absorption by the package and circuit
2. Hydrogen effects – Hydrogen induced breakdown of portions of the circuit (Metal)