Test and Physical Laboratories
Accelerating time-to-market, the Dialog way
Leveraging the outsourcing model to its fullest for volume manufacturing, we still retain a prototype test facility, including physical analysis capabilities in-house. This facilitates fast ramping to volume manufacturing at the foundry and at packaging and testing sub-contractors, achieving best in class industry yields and extremely high quality and reliable products. Equally important, it allows us to minimize the scope of tests required and the device test time, helping to reduce unit costs.
In-House Test Facility
In Dialog’s Kirchheim, Germany manufacturing center is a 50 sq.m., Class 1000 clean room equipped for state-of-the-art wafer probe testing. Our test labs are fully integrated, true mixed-signal test environments with advanced, mixed-signal Teradyne testers, including the iFlex™ and earlier Catalyst™ test systems, to mirror the test environment of our sub-contractors. Within these labs, our chips are tested for the first time at wafer level to test functionality.
Test programs for packaged parts are first developed and optimized in-house, including local design of the load boards (upon which devices are mounted for testing). In this way, a complete and proven test environment can be delivered to the sub-contractors for every device and the same environment is maintained in Dialog’s prototype test.
State-of-the-Art Data Processing
We've built a comprehensive and efficient manufacturing data warehouse which allows online access to detailed information for all of the products shipped to our customers. Additionally, we preserve the electrical test data integrity of each chip that has passed through our quality gates. This is essential for tractability and historical product investigation purposes.
Expertise in Manufacturing Software
Dialog has a dedicated team of software developers that are continuously improving and automating our manufacturing processes by creating smarter and safer interfaces between the different types of equipment we use, including testers, probers, handlers, and operator interfaces.
Our fabless business model doesn't stop us from retaining a uniquely tight rein on quality and reliability through our investments in our own test and physical laboratories. This approach ensures the fastest possible time-to-market for new devices, and levels of technical support for customers that most fabless semiconductor companies can only dream of attaining.
Advanced, small geometry bond testing includes both wire pull tests and wire-ball shear tests to determine the strength of bonds and ultimate failure mechanisms. The physical laboratory is equipped with ESD and latch-up testing capabilities, which allow tests to be carried out following the Human Body Model, creating pulses between 50V and 8kV, in accordance with JEDEC standards.
Substrate and packaging design are also carried out in Kirchheim, where we offers a broad range of packaging options to customers for consumer, industrial and automotive applications.
Accelerated ageing can be done at various temperatures (normally 125 degrees Centigrade), having the electrical functionality verified at given time intervals. The standard ageing evaluation is 1000 hours, or some 8 weeks. This enables device performance to be extrapolated out to about 5 years of normal operation, although this can be extended to 17 years using longer test time and/or higher stress temperatures.
We have continued to invest in our physical laboratory, empowering Dialog’s ability to pro-actively enhance the quality and reliability of its devices, and improve manufacturing yields. Nearly 80% of the activities here are focused on evaluating working devices and looking for ways to improve them. Helping customers understand the likely performance of components within their operating environment, i.e. soldering onto a substrate, is an important part of the ongoing work in our physical laboratory.
A unique drop test for handheld devices (e.g. mobile phones) has been developed at our lab in Kirchheim that determines the quality of solder joints that attach BGA-packaged devices to printed circuit boards. This kind of information is fed back to sub-contract manufacturers enabling them to improve their processes and it is used to assist our customers in attaining their own quality goals. Compared to the JEDEC standard, which specifies an acceleration of 1500G, Dialog’s drop test evaluates what happens at accelerations up to 7500G. After being dropped, the package of the device under test is assessed as a measure of soldering quality.
The starting point for failure analysis is device identification and examination of the history of the part. Level 1 electrical tests are followed by non-destructive inspection, including X-ray examination and/or acoustic scans. Devices are then de-capsulated and inspected visually using optical microscopes. When required, inspection with a scanning electron microscope (SEM) is performed. Sample preparation plays an important role in failure analysis, and the lab has the ability and necessary equipment to make cross-sections of the packages and silicon chips, as well as performing chemical and mechanical die de-processing.
Driving quality advances
Product testing is a manufacturing cost, so reducing test time and performing multi-site testing is a key target. Dramatic improvements are experienced between early batches, with yields rising from 75% to 98% or higher by the time the product is in volume production. The test time is dramatically reduced during this process and the cycle time to create this improvement can be as short as 1 to 3 weeks – an achievement that only comes as a result of investment in in-house facilities.
The Teradyne-based prototyping testers at our Kirchheim manufacturing site are capable of handling advanced packaging technologies, with packages of up to 250 contacts. They combine fast throughput with accurate, reliable results. Our test sub-contractors use equivalent testers, ensuring consistency throughout the test programs, wherever in the world they are carried out.