History
At the beginning of the 1970s a relatively high failure rates of electronic components were tolerable in automobiles, because they replaced mechanical components, which had a much higher failure rate. The underlying failure rates of bimetallic flashers were 10% per year and the lifetime of mechanical ignition contacts at 10,000 miles. With the increasing number of semiconductors in control units, and the introduction of the first safety systems (ABS) in the 70s had to be addressed. Already in 1975, the General Specification for IC's in Automotive Applications [1] as the first SAE Recommendation was issued, the 1978 SAE standard [2] was declared and adopted by major semiconductor manufacturers.
The establishment of the Automotive Electronic Council (AEC) 1994 by Ford, Chrysler, GM - Delco was also the Starting point for the AEC-Q100 qualification process, [3] was based on the SAE standards.
Due to the development of automotive and the ever-increasing complexity of vehicles associated with the demands for lower error rates of this qualification process, this process to decide by nonspecific tests, to cover a wide range of possible failure mechanisms, but only on the functionality of the component is out of date. In order to make statements about the robustness AEC Q100 can be replaced robustness validation.
Contents
Robustness Validation is used to assess the reliability of electronic components by comparing the specific requirements of the product with the actual "real life values". With the introduction of this methodology, a specific list of requirements (usually based on the OEM) is required. The requirements for the product can be defined in the environmental requirements (mission profiles) and the functional requirements (use cases).
Mission profiles
The mission profiles describes the loads and stresses acting on the product in actual use. These are, for example, changes in temperature, temperature profile, vibration and working of electrical and mechanical fields, or other environmental factors. It is important to specify the relevant stressors in their nature, intensity and duration of exposure, as well as the mix as closely as possible. With these details it is possible, within specified accuracy, projections regarding reliability of application and its components in field applications.
Use cases
The use cases describe the nature and frequency of the operating conditions for which the product is designed. One should make sure that this addition to the normal operation of the possible cases of special operation and emergency operation. Intentional abuse is not included.
Robustness margin
The lifetimes can be hedged by specific, tailored to the application and the failure mechanisms, determined tests. An essential process are End of life tests. From the distance of the requirements to the test results, the reliability and robustness of the device can be determined.
Product development
Today's standard qualification procedures for electronic components, assemblies and components for the automotive industry is based on the use of standardized tests at the end of the product development of parts and components. In contrast, Robustness Validation is a process that includes the entire product development process, as well as mass production. The qualification of the components based on the robustness analysis is thus implicit. With the introduction of robustness validation, priorities are focused on the development process again. The aim is to reduce the construction error's during the later phases of the project, which means front loading measures in the product development time line process.
It is necessary that the requirements from the product to the next level of the value chain be broken down in order to meet specific statements about possible vulnerabilities. Back in the early phases of the project is the knowledge (e.g., from knowledge bases Lessons Learned) gained from previous projects in order to avoid known vulnerabilities. Using the analysis of the changes of the new product and the use of different methods, such as REM, RBFM or design reviews, new potential vulnerabilities are identified early in order to make potential risks
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 tribocharging or by electrostatic induction. The ESD occurs when differently-charged objects are brought close together or when the dielectric between them breaks down, often creating a visible spark.
In software project management, software testing, and software engineering, verification and validation (V&V) is the process of checking that a software system meets specifications and requirements so that it fulfills its intended purpose. It may also be referred to as software quality control. It is normally the responsibility of software testers as part of the software development lifecycle. In simple terms, software verification is: "Assuming we should build X, does our software achieve its goals without any bugs or gaps?" On the other hand, software validation is: "Was X what we should have built? Does X meet the high-level requirements?"
Failure mode and effects analysis is the process of reviewing as many components, assemblies, and subsystems as possible to identify potential failure modes in a system and their causes and effects. For each component, the failure modes and their resulting effects on the rest of the system are recorded in a specific FMEA worksheet. There are numerous variations of such worksheets. An FMEA can be a qualitative analysis, but may be put on a quantitative basis when mathematical failure rate models are combined with a statistical failure mode ratio database. It was one of the first highly structured, systematic techniques for failure analysis. It was developed by reliability engineers in the late 1950s to study problems that might arise from malfunctions of military systems. An FMEA is often the first step of a system reliability study.
Automatic test equipment or automated test equipment (ATE) is any apparatus that performs tests on a device, known as the device under test (DUT), equipment under test (EUT) or unit under test (UUT), using automation to quickly perform measurements and evaluate the test results. An ATE can be a simple computer-controlled digital multimeter, or a complicated system containing dozens of complex test instruments capable of automatically testing and diagnosing faults in sophisticated electronic packaged parts or on wafer testing, including system on chips and integrated circuits.
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.
The Automotive Electronics Council (AEC) is an organization originally established in the 1990s by Chrysler, Ford, and GM for the purpose of establishing common part-qualification and quality-system standards.
Integrated logistic support (ILS) is a technology in the system engineering to lower a product life cycle cost and decrease demand for logistics by the maintenance system optimization to ease the product support. Although originally developed for military purposes, it is also widely used in commercial customer service organisations.
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 hazard analysis is used as the first step in a process used to assess risk. The result of a hazard analysis is the identification of different types of hazards. A hazard is a potential condition and exists or not. It may, in single existence or in combination with other hazards and conditions, become an actual Functional Failure or Accident (Mishap). The way this exactly happens in one particular sequence is called a scenario. This scenario has a probability of occurrence. Often a system has many potential failure scenarios. It also is assigned a classification, based on the worst case severity of the end condition. Risk is the combination of probability and severity. Preliminary risk levels can be provided in the hazard analysis. The validation, more precise prediction (verification) and acceptance of risk is determined in the Risk assessment (analysis). The main goal of both is to provide the best selection of means of controlling or eliminating the risk. The term is used in several engineering specialties, including avionics, chemical process safety, safety engineering, reliability engineering and food safety.
IEC 61508 is an international standard published by the International Electrotechnical Commission consisting of methods on how to apply, design, deploy and maintain automatic protection systems called safety-related systems. It is titled Functional Safety of Electrical/Electronic/Programmable Electronic Safety-related Systems.
Validation is the process of establishing documentary evidence demonstrating that a procedure, process, or activity carried out in testing and then production maintains the desired level of compliance at all stages. In the pharmaceutical industry, it is very important that in addition to final testing and compliance of products, it is also assured that the process will consistently produce the expected results. The desired results are established in terms of specifications for outcome of the process. Qualification of systems and equipment is therefore a part of the process of validation. Validation is a requirement of food, drug and pharmaceutical regulating agencies such as the US FDA and their good manufacturing practices guidelines. Since a wide variety of procedures, processes, and activities need to be validated, the field of validation is divided into a number of subsections including the following:
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.
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.
Automotive electronics are electronic systems used in vehicles, including engine management, ignition, radio, carputers, telematics, in-car entertainment systems, and others. Ignition, engine and transmission electronics are also found in trucks, motorcycles, off-road vehicles, and other internal combustion powered machinery such as forklifts, tractors and excavators. Related elements for control of relevant electrical systems are also found on hybrid vehicles and electric cars.
An operating temperature is the allowable temperature range of the local ambient environment at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the maximum operating temperature. Outside this range of safe operating temperatures the device may fail.
ISO 26262, titled "Road vehicles – Functional safety", is an international standard for functional safety of electrical and/or electronic systems that are installed in serial production road vehicles, defined by the International Organization for Standardization (ISO) in 2011, and revised in 2018.
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.
The OPEN Alliance is a non-profit, special interest group (SIG) of mainly automotive industry and technology providers collaborating to encourage wide scale adoption of Ethernet-based communication as the standard in automotive networking applications.
The Center for Advanced Life Cycle Engineering (CALCE) is a university research facility focused on risk assessment, management, and mitigation for electronic products and systems. CALCE is the largest electronic products and systems research center focused on electronics reliability and is dedicated to providing a knowledge and resource base to support the development of competitive electronic components, products, and systems. CALCE is located at the University of Maryland in College Park, Maryland, and was founded by Professor Michael Pecht.
