In-depth analysis of the quality management system and specification of automotive electronic components
With the increasing popularity of new energy vehicles, the automotive industry has put forward higher requirements for the safety of automotive electronics. In this industry chain, the automotive production system is usually quality first and function second. Among them, the whole vehicle parts are closely related to the safety of the vehicle control system. Every component needs to achieve the highest quality and reliability, and even achieve the ideal state of zero defect.
The biggest driving force of auto parts and related products is often not advanced technology, but more of the level of quality; and the improvement of quality requires strict control procedures to achieve. At present, important quality management systems and related specifications in the automotive industry include various specifications proposed by the Automotive Electronics Council (AEC), as well as QS-9000 and TS 16949. In addition, parts suppliers will also propose their own specifications, such as ST's Automotive Grade Qualification.
1. AEC series specifications
Chrysler, Ford and GM/Delco Electronics created the Automotive Electronics Council (AEC) to establish a common set of standards for parts qualification and quality systems. AEC has established quality control standards. At the same time, since the parts that meet the AEC specifications can be adopted by the above-mentioned three car manufacturers at the same time, it has promoted the willingness of parts manufacturers to exchange their product characteristic data, and promoted the implementation of the universality of auto parts. Lay the foundation for the rapid growth of the auto parts market.
AEC-Q100, a certification specification dedicated to chip stress testing (Stress Test), is the first standard of AEC. AEC-Q100 was first published in June 1994, and after more than ten years of development, AEC-Q100 has become a common standard for automotive electronic systems. During the development of this document, important chip suppliers were given the opportunity to provide their input.
This specification enables automotive components to meet the procurement needs of the automotive market more quickly. Automotive electronic components are considered high quality and reliable as long as they meet the requirements of this specification, and can be suitable for the complex and harsh environment of automotive applications without the need for repeated cyclic qualification testing.
After AEC-Q100, AEC has successively formulated specifications such as AEC-Q101 for discrete components and AEC-Q200 for passive components, as well as guidelines such as AEC-Q001/Q002/Q003/Q004. A brief introduction will be given below:
The AEC-Q100 standard is mainly to prevent various possible situations or potential errors of products, and guide suppliers to produce chips that meet this specification during the development process. AEC-Q100 conducts strict quality and reliability confirmation for each application case, that is, to confirm whether the product data sheet, purpose of use, function description, etc. proposed by the manufacturer conform to the functions originally declared, and whether after repeated use can always be the same.
The biggest goal of this standard is to improve product yield, which is a big challenge for chip suppliers in terms of product size, pass rate and cost control. AEC-Q100 specifies various requirements for IC chips in detail. On the other hand, it also represents the requirements of car manufacturers and suppliers for product safety.
This standard specifies a series of tests in detail, and defines the minimum requirements for stress test-driven certification and reference test conditions for IC certification. These tests include 7 test groups: test group A (accelerated environment stress test, Accelerated Environment Stress), test group B (lifetime simulation test, Accelerated Lifetime Simulation), test group C (package assembly integration test, Package Assembly Integrity), Test Group D (Chip Wafer Reliability Test, Die Fabrication Reliability), Test Group E (Electrical Characterization Confirmation Test, Electrical Verification), Test Group F (Defect Screening Monitoring Test, Defect Screening), and Test Group G (Cavity Package Integrity).
In addition, in order to meet the high standards of operating temperature, durability and reliability of automotive electronic products, component suppliers must adopt more advanced technology and more stringent testing procedures to achieve optimized design methods. Therefore, AEC-Q100 is divided into different product grades, in which the operating temperature range of the first grade standard is between -40°C to 125°C; the most stringent grade 0 standard operating temperature range can reach -40°C to 150°C .
Zero defect is the goal that all industries are constantly pursuing. In the automotive electronics industry, which has higher requirements for safety, the requirements for quality are more stringent.
The defect rate of semiconductor components is represented by DPM (Defect Per Million). In some critical application components, suppliers even increase the defect rate from the commonly used Parts Per Million (PPM) unit to one billionth (Parts Per Billion, PPB), namely A problematic product can only occur for every billion components produced. Therefore, by effectively controlling the DPM, the driving safety problems caused by the malfunction of electronic devices can be reduced.
The so-called Parametric Part Average Testing (PPAT) method is proposed in the AEC-Q001 specification. PPAT is a statistical method used to detect abnormal characteristics of semiconductor components at the outer edge (Outliers), and is used to exclude abnormal components from all products.
PPAT can be divided into static PAT (Static PAT), dynamic PAT (Dynamic PAT) and regional PAT (Geographic PAT). The so-called regional PAT is to add proximity weighting to all the bare die on the wafer. ), so some good dies surrounded by or adjacent to bad dies may also be removed.
Generally, AEC-Q001 only requires passing the static PAT test. However, in order to achieve higher quality, ST's automotive grade certification requires simultaneous static, dynamic and regional PAT standards. In addition, ST's regional PAT also uses Repeatable pattern detection and Composite Analysis to improve control quality. With PPAT, dies that are outside the test limits are removed, even if those dies meet the characterization requirements. This avoids potential risks and improves the quality and reliability of components at the supplier stage.
AEC-Q002 is based on statistical principles and belongs to the guiding principles of statistical yield analysis. The Statistical Yield Analysis (SYA) of AEC-Q002 is divided into two types: Statistical Yield Limit (SYL) and Statistical Bin Limit (SBL). In the case of SBL, it places special monitoring functions on the BIN during the Electrical Wafer Sort (EWS) stage, and each area is sampled and analyzed. These methods establish a system for analyzing and controlling production variables by measuring key test parameters/BINs, which can be used to detect abnormal material areas and ensure the quality and reliability of the final product.
All new components or technologies can be statistically analyzed at different stages before and after the manufacturing process, and can also be used for electronic parametric testing during wafer testing (Wafer Probe) and final testing of packaging. AEC-Q002 provides component manufacturers with a method to use statistical techniques to detect and remove abnormal chip components, allowing manufacturers to detect errors early and reject them at the wafer and die stage.
Product and process characteristics are very important for developing new chips or making adjustments to existing chips. Characterized parts produced at the edge of the process, or specially selected extreme parameter values, can be used to determine the sensitive process range.
Suppliers can change or strictly handle this part of the process, or remove this part of the product during the testing phase. When new design techniques and processes are involved in new components, characterization operations are performed during wafer testing or final testing. By determining the electrical properties and process parameters and performance limitations, the function and parameter performance characteristics of the product can be established, and the supplier can also identify the process area (Sweet Spot) that can be properly controlled.
AEC-Q003 is a guiding principle for the characterization of the electrical performance of chip products. It is used to generate product, process or package specifications and data sheets. Learn about the properties, performance, and limitations of this component and process, and examine the performance of these components or devices for parameters such as temperature, voltage, frequency, and more.
AEC-Q004 proposes a series of process steps, including component design, manufacturing, testing, and use, and what process zero-defect tools or methods are used in each stage of the process. These methods cover the various document standards of the AEC mentioned above, as well as the wide application of quality control techniques or management systems from the industry such as JEDEC or AIAG. When a part or process has been optimized and maturity is demonstrated over time, quality and reliability can be improved or maintained with fewer tools.
AEC-Q004 is essentially a set of zero-defect guidelines, which defines how chip suppliers or users can use some tools and processes in the product life cycle to achieve zero-defect goals. AEC-Q004 is not a mandatory specification, but proposes tools and methods to reduce defects. Different application modes will require different tools or production methods, so suggested practices are presented in this guideline. AEC-Q004 is still in the draft stage, and the official version will be released soon.
2. QS 9000/TS 16949 specification
The quality management system certification system of QS 9000 and TS 16949 is another set of specifications that automotive electronics suppliers need to pay attention to in addition to AEC.
QS9000 was once the basic quality management system for automobile suppliers to produce parts, materials and provide services, mainly based on the ISO 9001:1994 system, which was jointly developed by Chrysler, Ford and General Motors in 1994. It was replaced on December 15, 2006 by the ISO/TS 16949 automotive industry verification standard formulated and implemented by the International Automotive Task Force (IATF).
The TS16949 standard is based on ISO 9001: 2000 and is a quality system management standard for the automotive industry. At present, it includes GM, Ford, Daimler Chrysler, Peugeot, Renault, BMW, Nissan, Fiat, Volkswagen and other world-class car manufacturers. It is mandatory for the quality management system of its suppliers to comply with the requirements of TS 16949, and it is required to be extended to 2-3 level suppliers.
TS16949 highlights the main axis of customer orientation and develops various performance indicators. Its system operation structure can strongly promote the continuous improvement of the organization, so as to maintain the competitiveness of leading the industry, so that managers can effectively find abnormal points and make corresponding improvements.
The full name of PPAP is Production Parts Approval Process, which is a more important practice in QS 9000 and TS 16949 specifications. PPAP requires that all parts used in the automotive supply chain must have detailed and complete data and documents, and the PPAP documents list the production and quality assurance procedures that chip manufacturers need to take. These documents support the customer's production approval process and associated hazard assessment.
PPAP is used to confirm that the supplier has correctly understood all the requirements in the customer's engineering design records and specifications during the actual mass production of the part, and to ensure the buyer's quality risk, assessing whether it has the potential ability to continue to meet these requirements.
ST's automotive grade certification
The quality and reliability of in-vehicle products are much higher than other ordinary consumer products. In order to meet the unique needs of this market, chip suppliers are actively working to improve the technology and management system of mass production control and develop more reliable mass production. In addition, we also strive to use this set of technologies to improve product quality in other application areas such as consumer.
The requirements of AEC (especially AEC-Q100, AEC-Q101, AEC-Q001/Q002/Q003, etc.) and PPAP are the design specifications that automotive products need to follow, so there are obvious differences between automotive products and other products: It must strictly adhere to the defined product characteristics, design and manufacturing procedures, etc., and provide users with complete documentation and product packaging.
ST has proposed strict Automotive Grade Qualification (Automotive Grade Qualification) specifications. In addition to meeting the above-mentioned AEC and quality management system specifications, ST has also developed special screening and testing methods in the process, as well as a dedicated High Reliability Certified Flow (HRCF) testing program. Wait for a set of strict control methods.
1. Product screening method
Improved stress testing (Stress Testing) and screening method (Screening) is an important part of ST automotive grade certification specifications. The results of its screening will be used as the direction of product improvement, and the goal is to have zero-defect automotive electronic components.
Due to the particularity of in-vehicle systems, it is generally considered to be a good product in standard process tests, but there may be potential danger of failure under certain conditions in automotive applications. Through the method of product screening, it can be used for further strict screening. Rigorous product testing often takes more time and cost to market. In order to pass these tests in the shortest time, some effective methods must be adopted, such as the practice of maximizing Product-Family Data and Technology Dependent.
The qualification standard defined by AEC-Q100 is based on the product family (Product Family). The so-called product family maximization principle means that among all products using the same process and materials, as long as one member passes the test, the other product family members can pass the test; the technical dependency is based on the process standard as the audit object, as long as it is adopted. New products produced by already qualified process standards represent a very high probability of being qualified.
2. HRCF test procedure
The temperature range of automotive components is generally -40 ℃ ~ 125 ℃, so products such as EEPROM and flash memory often need to meet extremely strict production yield and reliability requirements. ST has developed a test procedure called High Reliability Qualification Flow (HRCF) for EEPROM and Flash memory for automotive electronics applications. HRCF is a proprietary production process that incorporates additional modules into the production, testing and quality assurance acceptance process to ensure that the product operates within the temperature range of automotive applications. In the production module, the bare die of the EEPROM must be able to perform 3000 cycles of erasing and writing in an environment with a rising supply voltage. In the bare die test, it also needs to pass a high temperature bake at 250°C for 24 hours, and still needs to pass the electrical test in the next second. The final tested modules included temperature cycling and electrical testing at 130°C and room temperature.
The HRCF test flow combines statistical tools such as Statistical Box Limiting (SBL) and Part Average Testing (PAT) to screen out early failures and outliers on both wafer and die to achieve the automotive zero-defect reliability goal.
The current automotive electronics market is developing rapidly, and product types are becoming more and more diverse. Therefore, in order to ensure the versatility and quality of automotive parts and electronic products, strict quality control specifications and management systems are required to ensure that. The quality specification can be a set of recognized specifications such as AEC and TS 16949, or it can be a customized management system proposed by the supplier similar to ST's automotive grade certification.
In addition to ensuring product quality, reasonable management practices can also accelerate the supply of the entire automotive industry chain. It helps improve pipeline visibility, customer tracking, and order status tracking between automakers and component suppliers can also be made easier. In addition, in order to obtain lower manufacturing costs and more flexible design capabilities of automotive electronic product suppliers, in addition to developing supply channels for small companies, the most effective support for production capacity and rapid grasp of the application requirements of car manufacturers The state of the technology is very important, and these tasks can also be achieved through a sound supply chain management system.
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