Attending the SEMIIndustry Strategy Symposium (ISS) is like drinking from a fire hose with the additional risk of whiplash. Don’t get me wrong, it is an exquisite fire hose but sometimes the data presented can be overwhelming at this conference of semiconductor supply chain executives. The majority of the attendees and presenters are executives from the SEMI member companies that develop the equipment, materials, processes, and technology used to build, test, and package semiconductors. And the executives present from the semiconductor manufacturers are typically the “end customers”.
The greatest value of SEMI ISS, beyond the networking, is the strategic overview of the entire semiconductor ecosystem. What are the market drivers, the technology needed, and the roadmap status of this industry? It is true that we all know where we need to head courtesy of Moore’s Law and the International Technology Roadmap for Semiconductors which attempts to keep us on that trajectory. The pressure of consumers needing wanting greater functionality at lower costs is relentless. Much of the technological detail of this ecosystem is addressed in a myriad of other forums throughout the year. ISS ties these technical requirements, development needs, and business needs back to the strategic direction and desires of the global marketplace.
Mervi Paulasto-Kröckel (Professor, Aalto University) in “On the Reliability Characterization of MEMS Devices” examined the current methods for reliability assessment in MEMS devices and identified necessary improvements. Currently, the reliability of MEMS devices are evaluated in the functioning state. A sensor is tested by applying a known stimulus and comparing the sensor output while varying the test conditions such as temperature, humidity, etc. MEMS actuators are similarly tested by providing a known input and measuring the output of the actuator over the range of test conditions. Significant deviation between the expected and measured result indicates a failure. Simple functional test is appropriate for manufacturing quality testing however it is inadequate for measuring and improving device reliability.
Pavan Gupta (Vice President of Operations, SiTime) provided a cautionary tale in “Packaging and Reliability Qualification of MEMS Resonator Devices”. Historically many MEMS companies have failed to start the device and packageco-design as early as possible even though packaging was upwards of 80% of the product cost. [Perhaps they aren’t really using a concurrent engineering methodology?] Even though the cost of packaging has dropped significantly, the complexities and risks related to packaging remain high.
There are many challenges related to MEMS packaging since without a reliable and qualified package, it is not possible for one’s customers to easily and confidently integrate a MEMS product into their end product. In SiTime’s case they had a double challenge of Continue reading “MEMS Testing and Reliability 2012 – Session 3”
Mårten Vrånes (Director of Consulting Services, MEMS Journal) in “A Test-centric Approach to MEMS ASIC Development” discussed alternatives to the traditional co-design of the MEMS element and application specific integrated circuit (ASIC). As many MEMS devices require an ASIC to control and/or sense the MEMS element the most logical approach is to design both parts in parallel. However the scope of such a development effort is often beyond the resources – both in terms of talent and funding – for many companies especially startups.
Mario Correa (MEMS Test Engineering Manager of Fairchild Semiconductor) started with “Evolution of MEMS Test Solutions” reviewing how test equipment and processes have evolved from the 1960’s to today. There have been major changes to test methods developed for non-MEMS sensors first used with military and aerospace MEMS sensors in the late 1960’s where the annual volume was measured in thousands of units to those used today for over three billion units shipped yearly to the consumer electronics market. It has been a challenge keeping up with the high triple digit growth rates from 2009 to 2012 including gyroscopes +189%, microphones +347%, and digital compasses +778%. MEMS accelerometers grew “only” +78% during this period. (Growth data per Yole)
This year’s IEEESemiconductor Wafer Test Workshop started on Sunday June 10th with a pleasant surprise. Due to a welcomed but unexpected wave of seventy walk-in registrations, there was insufficient seating at the opening dinner. Thankfully the hotel staff quickly adjusted to accommodate these additional guests. Attendance and interest in this year’s workshop was clearly up.
Jerry Broz, general conference chair, welcomed everyone with a brief overview and presented prizes for the first annual golf tournament. We then quickly proceeded with business as Matt Nowak (Senior Director, Advanced Technology, Qualcomm CDMA Technologies) provided the keynote “Emerging High Density 3D Through Silicon Stacking (TSS) – What’s Next?” Mr. Nowak discussed the increased amount of hype within the 3D semiconductor packaging market in the last year with everyone announcing something. And Thru Silicon Vias (TSVs) technology has already been in high volume production for image sensors for several years now but at a significantly lower density than for 3D packaging.
Usual business advice includes thinking big to win big. Some organizations create Big Hairy Audacious Goals. Others like to find new markets that are underserved and grow to be number one. The semiconductor industry has Moore’s Law – the premise that the minimum cost point is achieved by doubling the number of transistors per chip every two years – driving it forward for almost fifty years.
Janusz Bryzek set a dramatic and ambitious goal of $1 trillion sales for the microelectromechanical systems (MEMS) market in 2022. Even though the MEMS market is expected to have “only” $12 billion in revenue in 2012, he isn’t being called a fool. Having cofounded eight seminal Silicon Valley MEMS companies and currently the Vice President of MEMS Development at Fairchild Semiconductor (which recently acquired his last company), Janusz is taken quite seriously.
Limitations imposed by extreme temperature, extreme pressure, and toxic materials combined with a typically slow deposition rate make it is difficult to economically run these processes on an industrial scale for high volume manufacturing. But what if there was a process that Continue reading “Green on the Industrial Scale”
As the final presenter at this week’s IEEESemiconductor Wafer Test Workshop (SWTW), I outlined how critical it is to understand the true cost of a product’s architecture in “Probe Card Cost Drivers from Architecture to Zero Defects“. Without a proper understanding of these costs – especially for fully custom high technology products such as wafer test probe cards – it is impossible to maintain a sufficient gross margin. Gross margin is essential to maintain the health of a company and to fund the research & development required for innovation.
Yes, there were a few in the audience who appeared pleased since they are confident that their products are on the right path. There were others who may have been upset based upon their company’s direction. I would argue that a proper diagnosis – regardless of how disturbing – is essential to drive the proper cure.
There is plenty of opportunity in the test market and reasons for optimism. The key to long term prosperity is to really understand the fundamentals of the business and not be blinded by the technology.
I thank those who stayed for the entire conference and welcome your thoughts below. And I will be posting more about the conference (including my summaries) in the next few weeks.
Early in my career in Hewlett-Packard manufacturing, we did a study that showed that the greater the configuration options we put on a single product the higher the cost to produce every other product in the same factory. Known as “Cost of Complexity” this has been found in many different industries with examples from software coding, to network support to food production. Not to mention in our own products, companies, and everyday lives.
Jay Thomas, Grund Technical Solutions, LLC., “Probe Cards with Modular Integrated Switching Matrices”:
For the last 30 years, most scribeline parametric testing has been approximately 85% Current-Voltage (I-V) testing and 15% Capacitance-Voltage (C-V) testing. For these types of tests a 10 MHz bandwidth switch matrix has been sufficient.
However, some of the larger fabs such as HP, IBM, and Intel have started performing pulsed Current-Voltage (PIV) and electrostatic discharge (ESD) testing. These customers started this type of testing about four years ago unknown to Agilent & Keithley (the two largest DC parametric tester suppliers). This PIV and ESD testing requires high frequency switch matrices with 1 GHz bandwidth. [For more about ESD testing please see Jay’s second presentation below in this session.] Continue reading “IEEE Semiconductor Wafer Test Workshop – Parametric / Scribeline Probing – Session Six (Tuesday)”
Gert Hohenwarter, GateWave Northern, Inc., “Hidden Performance Limiters in the Signal Path”:
For high frequency signals, designers typically pay attention to avoiding coupling to adjacent signal lines to prevent cross talk. However, they need to look at many other areas of the design including coupling to power or sense lines, signal impedance mismatch, resonances, and the power distribution/delivery system (PDS). Coupling and mismatch may lead to resonances which reduce the operating speed or reduce the switching margin. These areas may also increase crosstalk increasing noise levels and also reducing switching margin. In addition, problems in the PDS may also reduce operating speed or switching margin. Continue reading “IEEE Semiconductor Wafer Test Workshop – Signal Integrity – Session Five (Tuesday)”
When overwhelmed by production, “Test” or “Quality Control” must learn to think globally rather than just functionally. Historically most companies always test first-in, first-out (FIFO) but should be prepared to abandon that practice when facing a backlog. An analogy is a navigator letting the pilot know they are off course right now versus discussing history from three hundred miles ago and working their way up to the present.
Recently a colleague was concerned that his company’s test capacity was insufficient to test all their output in a timely manner. (They manufacture integrated circuits with several hundred devices on each wafer produced.) In fact, the backlog of parts to be tested was approaching six weeks since additional test cells were not ready. After he explained the multitude of reasons why the additional test cells were not ready and that production could not be slowed to match the available test capacity, I asked how they were handling the backlog. He appeared perplexed by my question and wanted to know why it wasn’t obvious that they would simply test them in FIFO order as they had always done. Continue reading “FIFO, LIFO or Fido? What to do first.”
Joel presented an overview of inkjet technology and how they are applying it to printing circuits. They have developed a process that allows them to inkjet a catalytic ink which after UV curing allows the electroless (e-less) plating of copper. Given the choice of inkjet systems from scanning formats where the print head moves to fixed heads where the material moves past the head they have a wide range of potential substrate sizes and formats to choose depending on the end application. Continue reading “IEEE Consumer Electronics Society – Conductive Inkjet Technology”
Balancing test coverage versus test cost. What does a test failure mean? Value of yield increase
… and how it impacts your bottom line!
A poorly implemented semiconductor test cell may pass integrated circuit (IC) parts that are either defective or have marginal performance. They can cause the electronic devices in which they will be assembled to either malfunction or completely fail. However, two other conditions require evaluation. Having false negative test “escapes” is expensive in terms of final product test failures, warranty costs, customer dissatisfaction, etc. In turn, the false positive test escapes needs to be balanced against the cost of false negative failures where otherwise good parts fail the tests and are discarded. Test engineers, product managers, quality engineers, and operational managers needs to make either implicit or explicit decisions as to the proper balance in adjusting the test limits. The goal is to cost effectively approach “zero defects” without “throwing out the baby with the bath water”.
A test process generally categorizes the item or device being tested as “pass” or “fail”. Sometimes passing devices are graded (typically by speed or other desired quality) and failing devices are often grouped by failure mode. “Coverage” is how well a particular test process measures the functionality and specifications of a given device. If every feature and specification is tested then it is said to have 100% test coverage. However, exhaustive testing is usually expensive due to long test times which translates in to operational costs including the depreciation of the test system and greater test setup complexity (equipment and development cost). Sometimes complete coverage is not possible or practical so there needs to be a trade-off between coverage and cost.