Reliability “Higher reliability for longer operation and reduced maintenance costs” CISSOID is devoted to electronics for harsh environments, in which quality and reliability are primary concerns as failures rapidly turn into heavy money expenses. For example, the failure of the electronic system assisting the drilling of an Oil & Gas well possibly causes the stand-by of the drilling, costing a lot of money especially in deep and off-shore wells. During the well operation, a failure is even more problematic because the sensors on the completion cannot be replaced, resulting in a low-performance application for the remaining exploitation time. Reliability is also very important in automotive applications as it both improves the safety of the car and decreases the maintenance costs. Similarly, safety and low maintenance costs make the reliability constraints very tough for avionics applications. An additional feature required by harsh environments applications is a long lifetime compared to standard electronics products. Automotive applications require lifetimes for their electronic systems ranging from 10 up to 15 years and the targeted lifetime of a plane is more than 30 years. “Efficient assessment of reliability requires high temperature components” Assessing the reliability and the lifetime is tricky as it is not acceptable to test a system for, say, 20 years before entering the market. Hopefully, we can use accelerated tests. One of the techniques consists of testing the circuits during a shorter period but at a temperature higher than the nominal operation temperature of the product. This method results in comparable levels of stress for the electronics as if the test had been carried out at the operation temperature but during a longer period of time. The lifetime of the circuit is then found by extrapolating the results from the accelerated test. For this kind of accelerated tests to be valid, circuits under test must remain operational, even with derated performance, when exposed to the high temperature stress. “High temperature components: a benefit for everyone” Accelerated testing is a very powerful tool for shortening the time-to-market and saving test time, and hence saving money. This technique is however no longer valid for systems which operate at the maximum temperature tolerated by the electronics inside. Indeed, you cannot get anymore the system working at a temperature higher than the nominal temperature. Assessing the reliability for an affordable cost and time is compromised. So even if your system nominal temperature of operation does not exceed 175°C, you have huge advantages using high temperature electronics as it enables accelerating the test time. Finally, by using our high temperature electronic components, you increase the reliability whilst shortening and simplifying the tests. No need for extra characterization on your side. "Case Study" To illustrate the mechanism of accelerated tests, you can find below a picture representing the effect on lifetime of electromigration on die metallization and its dependence with temperature.  Arrhenius Illustration
Based on this example curve, the table below indicates the acceleration factor that you can reach by testing at a higher temperature. If we take 150°C as the operating temperature for your application (factor = 1), you can see that the failures are accelerated by a factor of 40 if you test the component at 250°C. In other words, if you target a lifetime of 15 years at 150°C, we can validate that lifetime with a test at 250°C lasting only 5 months (3400h). | Actual temp. °C | Actual temp. °F | Acceleration factor compare to 150°C | Equivalent lifetime yrs | Equivalent lifetime hrs | | 150 | 302 | 1 | 15 | 131400 | | 175 | 347 | 3 | 5 | 44901 | | 200 | 392 | 8 | 2 | 17187 | | 225 | 437 | 18 | 1 | 7245 | | 250 | 482 | 40 | 0.4 | 3317 | We test all of our circuits to target 5 years reliability at 225°C. This illustrates the advantages of using High Temperature components, if there is only one failure mechanism dominating. As a system is always complex, a deep study of failure mode is necessary to be able tu use such equation and acceleration technique.
Traceability CISSOID traces all its manufacturing steps to be able to track every component from the design process to the customers' facilities. Information in our databases are kept for at least 15 years to guarantee traceability for long term applications. Our ERP system traces the following steps: - Design process
- Layout
- Manufacturing process
- Wafer number for each Run
- Test on wafer (and result mapping)
- Dicing
- Packaging
- Test on package components
- Stock location and mouvements (stock condition)
- Orders, Reception, Expedition, ...
A reference number is printed on each of our packaged parts to be able to trace their origin lots. For dies and wafers, our customers receive a report including the lot reference number. All our partners are qualified ISO9001 and use equivalent ERP systems to trace their manufacturing steps.
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