Automotive Test Advances: Implications on ASIC production tests for Fingerprint Cards AB - new requirements and yield consequences

Abstract

The purpose of the thesis was to study the safety and reliability requirements in the automotive industry from a production test perspective. A survey of the requirements in the automotive standard AEC-Q100 was conducted and the implications of compliance with the requirements were analyzed. In addition to this, production data was reanalyzed considering the requirements found in the survey. From this, conclusions regarding the necessity of new tests, new design requirements and potential yield reduction were drawn.

Popular Abstract

Almost every new mobile phone entering the market have a built in fingerprint sensor which can be used for unlocking the phone. When the finger is placed on the fingerprint sensor a ‘picture’ of fingerprint is taken and if it sufficiently similar to a stored template the phone is unlocked. This simple authentication concept can be applied to almost an infinite number of use cases. Possible applications are replacing PIN codes on credit cards, unlocking doors and integrating fingerprint sensors into automobiles. There are many features in the car which can be improved by adding a biometric authentication system. Imagine for instance a car which automatically configures your seat and rear view mirrors to your personal settings and starts playing your favorite playlist when you unlock it. In addition to this your insurance company is notified that you are driving the car and the insurance rate is adjusted according to your driving experience, age and record of previous accidents. As you drive along and pass a high way road toll the payment is authorized by placing your finger on the sensor rather than queuing and paying with a credit card. Similarly, parking fees are accepted by placing the finger on the sensor.

However, introducing new electronic components in the automotive industry is a long and cumbersome procedure since there are stringent safety and reliability requirements. All electronic designs has to be thoroughly tested before they are qualified for use in the automotive industry. For general purpose, non safety critical components the electronic circuit undergoes electrical and environmental testing and if all the tests are passed the design is said to be qualified for use in automotive applications. However, if the electronic component is to be used in a safety critical application, the entire development process has to be reviewed by an external auditor to make sure that sufficient considerations to possible consequences of a system failure has been taken. Also, safety critical systems are sometimes required to have built in self testing and diagnostics.

Due to the complex manufacturing process of modern electronics some of the produced devices will contain defects which may cause the device to fail. Such devices must be detected in order to avoid delivering faulty products to the customer. It is preferable if the faulty units are found early in the enrichment process in order to save cost by discarding the faulty devices before they are put into a package. Testing is essential in manufacturing of automotive grade electronics due to the long product lifetime. However, testing is also an increasing part of the manufacturing cost in modern electronics. Even though testing a circuit only cost a couple of cents a second and the test time is a fraction of a second in high volume production the total cost can be high. It can therefore be tempting to remove tests in order to save cost but that could lead to an increased number of test escapes, i.e. faulty devices that pass all production tests. On the other hand, adding new tests should be carefully considered. Adding a new test is a waste of money if it can not be proven that it increases the test coverage.

It is very likely that biometric authentication systems will be integrated in various automotive applications in the coming years. A part of the success will depend on the semiconductor manufacturers ability to provide reliable, safe and secure products.

• author: Felding, Henrik
• supervisor: Markus Törmänen
• organization: Department of Electrical and Information Technology
• course: EITM01 20171
• year: 2017
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Automotive electronics, production test, AEC-Q100, reliable electronics, dynamic testing, manufacturing of integrated circuits, Fingerprint Cards AB
• report number: LU/LTH-EIT 2017-570
• language: English
• id: 8909145
• date added to LUP: 2017-06-01 13:56:41
• date last changed: 2017-06-01 13:56:41