Resources Reports Database Insights Newsletters Whitepapers Video Teardowns			View Cart ()   Checkout   MySI Account   March 2003   Semiconductor Insights' Ray Haythornthwaite, Vu Ho, and Sue Brown. In Pursuit of Perfection: When Component Failure is Not an Option Semiconductor Insights, together with its affiliate MuAnalysis, have amassed one of the most talented and experienced Reliability Analysis / Failure Analysis (RA/FA) teams in the world. In the following interview, you'll meet this group of eclectic scientists and find out about some of the interesting and diverse projects they've been a part of, as well as get some insight into what they think are the challenges of tomorrow. Q: In your opinion, what are the top issues /challenges facing RA/FA professionals today? Haythornthwaite: Traditionally, engineering has solved problems by designing in reliability. But excessive heat generation, caused by ever-thinner gate oxides that increase transistor leakage, and smaller dimensions that cause high off state leakage, means more engineering or quick fixes aren't likely to solve the problems we'll be facing in the not too distant future. This ever-increasing mechanical chip fragility is magnifying the reliability challenge. Ho: Specialization within the industry is also posing huge challenges for the reliability professional. It is now quite common to have design, assembly, packaging and test all performed by separate companies, and this makes it more difficult to isolate the latent defect in a complicated logic circuit. As well, multiple players can make the ownership of RA/FA problems unclear which elongates the diagnosis and resolution effort. This is one of the key values SI brings to the mix with central problem ownership and time to market debug services.   High magnification image shows the gold aluminum intermetallics at the bonding site and the tungsten plug vias between the metal layers. [Download wallpaper image - 309k] Q: What questions are answered with a Reliability Construction Analysis (RCA)? And why is it needed? Haythornthwaite: RCA helps determine if a part is well made, rugged and likely to perform reliably without incurring the expense and scheduled delays of conventional reliability testing. Brown: Mass production of components is an industry trend. For board manufacturers, RCA plays an important role because it allows part evaluation and selection of the best quality active and passive components. Simard-Normandin: RCA is necessary because too often discrete components are selected on the basis of electrical parameters alone. Designers often overlook materials and compatibility issues because they focus too much on the electrical function. Q: What are the RA/FA issues facing flash memory devices? Haythornthwaite: From a construction point of view, critical oxides are getting thinner and the total area of oxide on a chip is increasing. Eventually, the memory writing mechanism will damage the oxide. We are approaching the stage where a single defect in the oxide, which is 1 atom thinner than usual, will decrease reliability significantly. The biggest challenge for RA/FA is to find these defect areas and prove to the engineers that you have correctly identified the problem.   Wire bond strength testing produced separation at the inter-metal dielectric interface to metal 5 layer. [Download wallpaper image - 162k] Q: What is the impact of technical advances like design complexity, transistor size miniaturization, increased device speed and new package technologies on the reliability of a device? Haythornthwaite: Technical advances and consolidation of many of the functions into a single System on a Chip (SOC) can improve reliability. However, processing latent defects such as tiny slivers of metal or minute amounts of corrosion, which once would have had little effect, can now completely destroy a system after a short exposure in the field. Ho: The use of low K dielectrics makes devices very fragile. Mechanical stresses arising from thinner packaging for higher heat dissipation, and larger package dimensions to accommodate higher pin counts, produce new reliability problems. Brown: Other problems arise from new packaging techniques, which often require innovative and unproven assembly processes. These new processes require further investigation into their mechanical strength and appropriate material content. Q: What about technologies operating at frequencies never previously anticipated? Today, device performance above 200 GHz and circuit performance about 100 GHz is routine. What are the innovations that have made this possible? Ho: Higher frequencies demand smaller dimensions and a revolution in technology to reduce propagation delays. Some of the innovations that have made higher levels of performance possible include: CMOS transistors with gate lengths down to 50 nm, SOI substrate, SiGe strained lattice, SiO2 gate oxide with a thickness of only 7 or 8 atoms, and high dielectric gate oxide, such as nitrided oxide, or hafnium dioxide in the near future, copper damascene metallization and low K dielectrics. Oliver: There is also a whole other family of materials and technologies that have to be considered including GaAs MESFET.   Cross-section through a ball bond attachment to the die pad of an integrated circuit. [Download wallpaper image - 267k] Q: Chips are being used in a broad range of applications today. We asked our experts to comment on some of the unique situations that have tested the limits of RA/FA. Haythornthwaite: I find recovery operations troubling to work on because of the circumstances surrounding them. In the case of the Swissair disaster, I was tasked with helping the investigators understand what caused the crash. Taking a badly damaged memory chip off of a board and reconstructing it helped identify the problem. In cases like this, where there is a single failed sample, accurate sample preparation and diagnosis is vital because there is no second chance if you make a mistake. Experience and patience are critical. Brown: More and more medical devices are being used within the human body, which is an extremely corrosive environment. So when performing reliability testing on a medical device that is going to be implanted, like a pacemaker, you must ensure that the seal on the packaging is perfect. Haythornthwaite: I've worked on many of the Canadian Space Programs including the Canadarm I and II, and their Commercial Satellite Project, ANIK. For the Canadarm project, I was responsible for the physical reliability testing of electronic components. What this amounted to was sampling components from 1000's of different batches to ensure consistency and reliability. Q: Are there other areas/sectors that you think could be improved by or benefit from RA/FA? Brown: From CAT scans to MRI's, from microsurgery to laser eye surgery; all of these procedures involve equipment that is highly dependent upon electronics. Today, you'll find more and more medical diagnostic equipment becoming reliant on semiconductor technologies for accurate performance and as such they will all benefit from careful screening to ensure best performance. Learn more about our scientific team (PDF, 41k)