O port

598

World Abstracts on Mlcroelectronlcs and Rehablhty

Finally, Jt IS suggested that no single set of measurements at one point m time can completely characterize a mlcrollthographic system Periodic monitoring of key measurable parameters during use is advisable

for higher power de,ices at lower cost are forcing packaging engineers to be more efficient and Innovative Thermal considerations are the paramount concern in power semiconductor packaging

E~olution and accomplishments of VLSI yield management at

In-circuit testing of LSI-based PCBs. TOM E FINNELL Elet-

IBM. C H STAPPER, P P CASTRUCCLR A MAEDEmW E ROWE and R A VERrIELST I B M Jl Res Day 26(5), 532 (1982) The methods developed at IBM to manage and improve the yield of some of its newer FET semiconductor products are described A number of visual mspectmn and electric monitoring techmques have evolved since &screte semiconductors were manufactured The data obtained with these techniques are used in self-checkmg ~leld models to give the relative ~lelds for all the yield components The results are apphed not only to day-to-day control of the manufacturing hnes, but also in the long-range forecasting and planning of future semiconductor integrated circuit products An example is given comparing the actual and planned yield of a 64 K-Nt random access memory chip as a function of time The results show the yield enhancement that was obtained with redundant circuits and addmonally with the use of partially functmnal products Another example shows the decrease in fault levels over a span of more than ten years

trontt Ptodn, 47 (September 1982) The in-circuit testing of LSI devices has, in the past, beet1 hmlted to the checking of functional operation--because of the effects of back-dave stress on surrounding devices With pattern application rates in the hundreds of kilohertz and back-drive hmltatlons of a few mllhseconds, only the barest paramets of device operanon could be tested As more comphcated VLSI devices appear in contemporary pcb assembhes, fewer and fewer parameters can be tested using ordinary methods, causing a marked decrease in the fault coverage of in-circuit testers when apphed to LSI-domxnated assemblies Using techniques pioneered by the VLSI component tester companies, most notably Falrchdd Test Systems Group of San Jose, Cahfornla, a suitable testing philosophy has been developed to markedly increase fault coverage of pcb assembhes containing LSI and VLSI Dubbed FAST-TEST, this innovative hardware architecture has been granted a patent by the US Patents Office, and was developed by Fairchild in their L~tham, New York, facility

Vacuum problems in today's integrated circuit manufacturing systems. Part It. PIERRE DUVAL Solid St Technol, 124 (September 1982) Semiconductor manufacturing trends have mmtlated industrial-scale processes tLPCVD, plasma deposmon, and plasma etching) employing dusty, corroswe or dangerous gases Creating a vacuum in these "dirt)" systems presents new problems for the designer New safety rules have to be introduced, and these have a strong impact on the development of vacuum pumps and auxdmry eqmpment These new challenges are examined, emphasizing the need for good tightness and elimination, under high-corrosion condmons, of solid particles generated either in the process itself or by secondary reactmns in the vacuum pump Selection criteria for vacuum pump lubricating otis and means of neutrahzlng the corrosive byproducts polluting the oll are also discussed It Is pointed out that the engineering of vacuum pumping systems needs to be slmphfied to improve rellabdlty of pumping speed control

Vacuum problems in today's integrated ClrCultmanufacturing systems. Part I. P1ERRI- DITVAI Sohd St Te~hnol 110 (August 1982) Semiconductor manufacturing trends have lmtlated industrml-scale processes ILPCVD. plasma deposition, and plasma etching) employing dusty, corrosive or dangerous gases Creating a vacuum m these "dirty" systems presents new problems for the designer New safety rules have to be introduced, and these have a strong impact on the development of vacuum pumps and auxllIar2¢ equipment These ne~ challenges are exammed, emphasizing the need for good tightness and ehminatton, under high-corrosion condmons, of sohd particles generated eJther in the process itself or b) secondary reactions in the vacuum pump Selecnon criteria for vacuum pump lubricating oils and means of neutrahzmg the corrosive byproducts polluting the off are also discussed It is pointed out that the engineering of vacuum pumping s~stems needs to be simplified to improve rehablhty of pumping speed control

Wire bonders: 1982 and beyond. Senuconductol

Int, 44 (August 1982) Orders for new wire bonders are reportedly increasing from both captive and contract assemblers While the offshore installations of wire bonders are stdl popular, stateside lnstallauons are increasing Fairchild and Motorola, among others, have plans for more "onshore" assembly facllmes In order to remain competitive for volume production, interest is in automatic systems

Power semiconductor

packaging

AARON WEISS Satinconductor Int. 85 (August 1982~ Increasing market demands

Process control of the chlorohenzene single-step liftoff process with a dmzo-type resist. GEORGE G COLLINS and CARY W HALSTED I B M Jl Res Dev 26 (5), 596 (1982) Introduction of the single-step chlorobenzene hftoff process using a dlazotype resist to manufacturing lines produced problems not encountered during development and pllot-hne work Variances in the structure of the photoresist hftoff image are the result of complex interactions among exposure, chlorobenzene soaking, development, and post-apphcatmn baking condmons Effects produced by these variables can be controlled by monitoring the hnewIdth, overhang, and height of the hftoff resist structure using a scanning electron microscope (SEM) Loss of resist thickness during the chlorobenzene soak is used instead of penetration, as measured on SEM photographs, to momtor the soaking process Data are presented on the creation and stabdlty of the overhang structure, the process controls required to achieve that stability. and the interactions among the process variables The process, as practtsed in a manufactmlng mode, was found to have greatest reproduceablhty at low exposure, with a combination of long soaking times and high post-apphcatlon baking temperatures

Leadframe materials for packaging semiconductors

S P

ZARLINGO and J R SCOTT Semuonductol /rit, 111 (September 1982) A comparison of leadframe materials is made m terms of electrical and thermal conductivity, strength and formabIhty, softening resistance, lead bend fatigue, and costs

Increase 1/O-handling options with a software serial 1/0 port. COSMA PABOUCTSIDIS Electronu Design New~, 117 (24 November 1982) A single-chip p.C's built-in serial port can hmit your options in I/O handbag You can implement a more versatile port in software, however, and get the capabllmes you need from a simpler land less expensive~ chip VLSI development system spans all phases of IC design. GENE CHAO, CHONG C LEE a n d TERRY SMITH Electronics, 105 (3 November 1982) Stand-alone 32-bit computer captures, simulates, and verifies both logical and physical designs of very large-scale integrated circuits Living Ill a 64K world. BETTY PRINCE Mtcroelectron Rahab 21 (6~, 775 [1981) MOS memory technology is currently moving into productmn at the 64 K density level with 64K