1、Lessons Learned Entry: 0604Lesson Info:a71 Lesson Number: 0604a71 Lesson Date: 1998-11-11a71 Submitting Organization: JSCa71 Submitted by: Ronald A. MontagueSubject: Microchip Susceptibility to Ionizing Radiation Emitted by Environment, Materials Used in Production and Processing of Computer Hardwar
2、e Description of Driving Event: The following was originally published by New Scientist magazine and picked up by Reuters. Two different JSC engineers have indicated that these radiation issues can cause concerns for NASA systems. The article is quoted verbatim.(from New Scientist/Reuters) Microchip
3、s are growing smaller, but their diminishing size exacts a price.Tiny circuits are vulnerable to radioactive interference that could cause a simple blip in your cell phone or a far more serious kind of crash, New Scientist magazine reported Saturday.When chips are miniaturized, they require less ele
4、ctrical charge to store each bit of information. Those decreased voltages also mean that the chips are less prepared to cope with low-level ambient radiation.“Unfortunately, the price we pay for smaller chips is as each chip has less voltage to work with and less charge, it can be more sensitive to
5、some of these soft error events,“ said Robert Bauman, manager for embedded memory and analog reliability at Texas Instruments.Radioactive interference can come from neutrons in the atmosphere or from the materials used in building the computer equipment, such as lead solder, silica molds, and the ph
6、osphoric acid used for etching. Those materials all emit radioactive alpha particles.“There is no simple solution to these things, we need to work with the materials-technology people to insure that the equipment contains fewer radioactive impurities,“ said Chand Provided by IHSNot for Resale-,-,-Vi
7、swanathan, professor of electrical engineering with the School of Engineering & Applied Science at the University of California at Los Angeles.Most PCs now use microchips with transistors between 330 and 250 nanometers across. The next generation of microprocessors should shrink to below 180 nanomet
8、ers, making them more susceptible to interference. A nanometer is one-billionth of a meter, roughly one-hundredth the width of a human hair or the size of one bacterial cell.Aircraft systems could face the worst problems of all, because the risk of interference goes up with the altitude.“When you ar
9、e flying five or six miles up, youre subject to more cosmic radiation effects,“ Viswanathan said.Texas Instruments has been working on the problem for almost a decade.“When youre doing your system design, whether its memory or high performance DSP, its important to have this radioactivity problem in
10、 mind as youre designing it. None of these problems are insurmountable,“ Bauman said.“Theres always a solution. The question is, whats the cost of solving it, and whats the cost if you dont solve the problem?“ Bauman said. “The risk depends on the applications and the acceptable error rate-you have
11、to factor that in. The best case is to design the system so theres no error.“One solution would shield the equipment from potential radiation, but that could prove impractical since some shields would have to be 10 feet thick. Equipment could also be placed in a basement, Bauman suggested.Another so
12、lution might be for designers to harden the chips against the effects of radiation, Viswanathan said.“The bottom line is, because it entails knowing nuclear physics, engineering, and so many varied disciplines, its not obvious to most people that its a problem,“ Bauman said.(from NanoSpace 98) Scale
13、d Silicon MOS is not nanotechnology.In contrast, recent measurement by the Naval Research Laboratory and Texas A&M show that nanosized quantum devices (Nanoelectronics) are extremely radiation tolerant and have the potential to lower power and increase speed in advanced signal processing and storage
14、 space systems. This was briefed at the NanoSpace 98 conference last week. For details on the nanosized quantum devices, contact Steven Watson of SAIC at (281) 244-1747 or Gary Provided by IHSNot for Resale-,-,-Frazier of Raytheon Systems at (972) 344-3634.Lesson(s) Learned: Some microchip technolog
15、y is getting more and more miniaturized, making previously used ionizing radiation controls obsolete. In contrast, some experts indicate that true nanotechnology processors are not as susceptible.Recommendation(s): 1. Ensure that materials used in processing and manufacture of microchips do not emit
16、 ionizing radiation which may damage the microchips during manufacture or test of microchips or electronic systems. Known examples of such materials are lead solder, silica molds, and phosphoric acid used for etching. The materials may be used actively like solvents) or passively (like molds). Mater
17、ials may be used in direct manufacture, test, maintenance, etc.2. Parts used in the manufacture of electronic systems utilizing microchip technology must also be scrutinized as potential radiation sources which may damage microchips.3. Where microchips will be susceptible to environmental radiation,
18、 ensure that design trade studies consider trade-offs such as additional weight from additional shielding, additional cost of radiation hardening of commercially available microchips, etc.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAddi
19、tional Key Phrase(s): a71 Environmenta71 Parts Materials & ProcessesAdditional Info: Provided by IHSNot for Resale-,-,-Approval Info: a71 Approval Date: 1998-11-16a71 Approval Name: Ronald A. Montaguea71 Approval Organization: NA3a71 Approval Phone Number: 281-483-8576Provided by IHSNot for Resale-,-,-
