Robustness Validation

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Robustness and English. robustness validation is a qualification strategy with which the robustness of a product against the load conditions of a real application is proven and specific statements can be made about risks and reliability . This strategy is particularly used in the automotive industry .

history

At the beginning of the 1970s, comparatively high failure rates of electronic components in automobiles could still be tolerated because they replaced mechanical components that had a much higher failure rate . The underlying failure rates of bimetal flasher units were 10% per year and the service life of mechanical ignition contacts was 10,000 km. With the increasing number of semiconductors in control units and the introduction of the first safety systems ( ABS ), additional action was required in the 1970s. As early as 1975, the General Specification for ICs in Automotive Applications was issued as the first SAE Recommendation , which was declared the SAE standard in 1978 and adopted by the major semiconductor manufacturers.

The founding of the Automotive Electronic Council ( AEC ) in 1994 by Ford , Chrysler , GM - Delco was also the starting point for the AEC Q100 qualification process based on the SAE standard.

This procedure is characterized by unspecific tests, which are intended to cover a broad spectrum of possible error mechanisms, but only decide on the functionality of the component. Due to the further development of automotive electronics and the constantly growing complexity in vehicles combined with the requirements for lower error rates, this qualification process is no longer up to date. In order to be able to make statements about the robustness, AEC Q100 is to be replaced by robustness validation.

Initiators and contributors

In April 2007, the Handbook for Robustness Validation of Semiconductor Devices in Automotive Applications was published with international cooperation from SAE, ZVEI , AEC and JSAE (Japanese Society of Automotive Engineers), in which the guidelines for the contemporary validation of semiconductor components in for use in Automobile are put together. Companies from the entire supply chain in the field of automotive electronics contributed to this. In addition to vehicle manufacturers and suppliers, a large group of semiconductor manufacturers has supplemented this qualification concept with an up-to-date database. This so-called knowledge matrix contains a list of currently known error mechanisms with causes, error methods and other information.

content

Robustness Validation is intended to evaluate the reliability of electronic components by comparing the specific requirements of the product with the actual "life values". With the introduction of this method, a concrete list of the requirements (usually based on the OEMs ) becomes necessary. The requirements for the product are divided into the environmental requirements (mission profile) and the functional requirements (use cases).

Mission Profiles

Robustness assessment according to Robustness Validation based on the comparison of application requirements, specification and technological limits of the component

The Mission Profile describes the loads and stresses that affect the product in real use. These are, for example, temperature changes, temperature profiles, vibrations and the effect of electric and magnetic fields or other environmental influences. It is important to specify the relevant stressors in their type, intensity and duration of exposure, as well as the mix as precisely as possible. With this information, projections with regard to the reliability of the application and its components in field use are then possible within the framework of the specified accuracy.

Use cases

The use cases describe the type and frequency of the operating states for which the product is designed. In addition to normal operation, the possible cases of special operation and emergency operation must also be listed. This is to be distinguished from inadmissible, knowledgeable abuse.

Robustness margin

The secured lifetimes are determined by special tests tailored to the application and the failure mechanism. End of life tests are an essential procedure . The reliability and robustness of the component can be determined from the distance between the requirements and the test results.

Product development

Robustness Validation Flow chart from product development to series production

The qualification procedures that are common today for electronic components, assemblies and components in the automotive sector are based on the application of standardized tests at the end of the product development of the components and components. In contrast to this, robustness validation is a process that includes the entire product development process as well as series production. The qualification of the components based on the robustness assessment is therefore implicit. With the introduction of Robustness Validation, priorities in the development process are redefined. The aim is to reduce the occurrence of errors during the later project phases, with frontloading measures having to be carried out earlier in the product development process.

It is necessary to break down the requirements from the product to the next level of the value chain in order to be able to make targeted statements about possible weak points. Knowledge (e.g. from knowledge databases, lessons learned ) from previous projects is used in the early project phases in order to avoid documented known weak points. With the help of the analysis of the changes to the new product and the application of various methods, such as FMEA , DRBFM or design reviews , new potential weak points can be identified in order to analyze and avoid possible risks at an early stage. The critical parameters established in this way are used to analyze the feasibility of the project and, if necessary, are included in the change to the initially established product requirements. In the validation, the proof of the functional feasibility and the reliability takes place, whereby the functional fulfillment and the implementation of the specification are checked.

Further fields of application for robustness validation

In addition to the publication of the manual on robustness validation for semiconductor components in 2007, another manual was published in the ZVEI in 2008, in which this procedure for the development and qualification of electronic control units in automobiles is described. There are other activities in the area of ​​sensors and electronic systems in vehicles.

Web links

Individual evidence

  1. ↑ General Specification for ICs in Automotive Applications, SAE Recommondation, 1975
  2. ↑ General Specification for ICs in Automotive Applications, SAE Standard, 1978
  3. ↑ Automotive Electronic Council's Stress Test Qualification for Integrated Circuits, AEC Q100, Rev. G, 2007, on aecouncil.com
  4. ↑ a b c Handbook for Robustness Validation of Semiconductor Devices in Automotive Applications ZVEI, 04/2007
  5. ↑ Knowledge matrix at zvei.org ( MS Excel ; 73 kB)
  6. ↑ Handbook for Robustness Validation of Automotive Electric / electronic Modules, ZVEI, 04/2008