Parts stress modelling is a method in engineering and especially electronics to find an expected value for the rate of failure of the mechanical and electronic components of a system. It is based upon the idea that the more components that there are in the system, and the greater stress that they undergo in operation, the more often they will fail.
Reliability engineering is a sub-discipline of systems engineering that emphasizes the ability of equipment to function without failure. Reliability describes the ability of a system or component to function under stated conditions for a specified period of time. Reliability is closely related to availability, which is typically described as the ability of a component or system to function at a specified moment or interval of time.
Environmental stress screening (ESS) refers to the process of exposing a newly manufactured or repaired product or component to stresses such as thermal cycling and vibration in order to force latent defects to manifest themselves by permanent or catastrophic failure during the screening process. The surviving population, upon completion of screening, can be assumed to have a higher reliability than a similar unscreened population.
A test engineer is a professional who determines how to create a process that would best test a particular product in manufacturing and related disciplines, in order to assure that the product meets applicable specifications. Test engineers are also responsible for determining the best way a test can be performed in order to achieve adequate test coverage. Often test engineers also serve as a liaison between manufacturing, design engineering, sales engineering and marketing communities as well.
Electronic packaging is the design and production of enclosures for electronic devices ranging from individual semiconductor devices up to complete systems such as a mainframe computer. Packaging of an electronic system must consider protection from mechanical damage, cooling, radio frequency noise emission and electrostatic discharge. Product safety standards may dictate particular features of a consumer product, for example, external case temperature or grounding of exposed metal parts. Prototypes and industrial equipment made in small quantities may use standardized commercially available enclosures such as card cages or prefabricated boxes. Mass-market consumer devices may have highly specialized packaging to increase consumer appeal. Electronic packaging is a major discipline within the field of mechanical engineering.
The ongoing reliability test (ORT) is a hardware test process usually used in manufacturing to ensure that quality of the products is still of the same specifications as the day it first went to production or general availability.
Microvias are used as the interconnects between layers in high density interconnect (HDI) substrates and printed circuit boards (PCBs) to accommodate the high input/output (I/O) density of advanced packages. Driven by portability and wireless communications, the electronics industry strives to produce affordable, light, and reliable products with increased functionality. At the electronic component level, this translates to components with increased I/Os with smaller footprint areas, and on the printed circuit board and package substrate level, to the use of high density interconnects (HDIs).
Reliability of semiconductor devices can be summarized as follows:
- Semiconductor 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 and package.
- The problems of micro-processes, and thin films and must be fully understood as they apply to metallization and wire bonding. 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 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, 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, contamination, voltage, current density, temperature, humidity, mechanical stress, vibration, shock, radiation, pressure, and intensity of magnetic and electrical fields.
An environmental chamber, also called a climatic chamber or climate chamber, is an enclosure used to test the effects of specified environmental conditions on biological items, industrial products, materials, and electronic devices and components.
Accelerated life testing is the process of testing a product by subjecting it to conditions in excess of its normal service parameters in an effort to uncover faults and potential modes of failure in a short amount of time. By analyzing the product's response to such tests, engineers can make predictions about the service life and maintenance intervals of a product.
Package testing or packaging testing involves the measurement of a characteristic or property involved with packaging. This includes packaging materials, packaging components, primary packages, shipping containers, and unit loads, as well as the associated processes.
Electronic components have a wide range of failure modes. These can be classified in various ways, such as by time or cause. Failures can be caused by excess temperature, excess current or voltage, ionizing radiation, mechanical shock, stress or impact, and many other causes. In semiconductor devices, problems in the device package may cause failures due to contamination, mechanical stress of the device, or open or short circuits.
The highly accelerated stress test (HAST) method was first proposed by Jeffrey E. Gunn, Sushil K. Malik, and Purabi M. Mazumdar of IBM.
HASA is a proven test method developed to find manufacturing/production process induced defects in electronics and electro-mechanical assemblies before those products are released to market. HASA is a form of HASS – a powerful testing tool for improving product reliability, reducing warranty costs and increasing customer satisfaction.
Physics of failure is a technique under the practice of reliability design that leverages the knowledge and understanding of the processes and mechanisms that induce failure to predict reliability and improve product performance.
Sherlock Automated Design Analysis is a software tool developed by DfR Solutions for analyzing, grading, and certifying the expected reliability of products at the circuit card assembly level. Based on the science of Physics of Failure, Sherlock predicts failure mechanism-specific failure rates over time using a combination of finite element method and material properties to capture stress values and first order analytical equations to evaluate damage evolution. The software is designed for use by design and reliability engineers and managers in the electronics industry. DfR Solutions is based in Beltsville, Maryland, USA, and was acquired by ANSYS, Inc. in May 2019.
Robustness validation is a skills strategy with which the Robustness of a product to the loading conditions of a real application is proven and targeted statements about risks and reliability can be made. This strategy is particularly for use in the automotive industry however could be applied to any industry where high levels of reliability are required
High-temperature operating life (HTOL) is a reliability test applied to integrated circuits (ICs) to determine their intrinsic reliability. This test stresses the IC at an elevated temperature, high voltage and dynamic operation for a predefined period of time. The IC is usually monitored under stress and tested at intermediate intervals. This reliability stress test is sometimes referred to as a "lifetime test", "device life test" or "extended burn in test" and is used to trigger potential failure modes and assess IC lifetime.
Solder fatigue is the mechanical degradation of solder due to deformation under cyclic loading. This can often occur at stress levels below the yield stress of solder as a result of repeated temperature fluctuations, mechanical vibrations, or mechanical loads. Techniques to evaluate solder fatigue behavior include finite element analysis and semi-analytical closed-form equations.
Reliability verification or reliability testing is a method to evaluate the reliability of the product in all environments such as expected use, transportation, or storage during the specified lifespan. It is to expose the product to natural or artificial environmental conditions to undergo its action to evaluate the performance of the product under the environmental conditions of actual use, transportation, and storage, and to analyze and study the degree of influence of environmental factors and their mechanism of action. Through the use of various environmental test equipment to simulate the high temperature, low temperature, and high humidity, and temperature changes in the climate environment, to accelerate the reaction of the product in the use environment, to verify whether it reaches the expected quality in R&D, design, and manufacturing.
