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Optics and electronics are living together
196
World Abstracts on Microelectronics and Reliability
rate also increases, drops suddenly at one cycle, then increases again. We discuss two reasonable industrial explanations of such unusual behavior. Measures of testability for automatic diagnostic systems. NAEL A. E. ALY and ADEL A. ALY. IEEE Trans. Reliab. 37(5), 531 (December 1988). This paper presents as investigation into the evaluation models of automatic diagnostic systems taking into consideration their imperfections such as failure to diagnose, incorrect isolation, false alarms, and can-not duplicate. Three measures of effectiveness are developed that enable the decision maker to assess accurately the real capability of the diagnostic system, and to evaluate and compare the performance of alternative automatic diagnostic systems based on their mean life-cycle cost. Analytic procedures for using these measures are developed, and an example is presented. Our conclusions are: • The capability and performance of automatic diagnostic systems can be assessed using three measures of effectiveness: false removal (7 error), failure to diagnose (fl error), and false alarm correction (7)- The 7 error represents problems that arise from false alarms, the fl error measures the capability of correct diagnosis, and y measures the ability of the diagnostic system to correct its actions after indicating a false alarm. These measures show the accuracy and precision of the diagnostic system and cover its imperfections. • The three measures of effectiveness can be used to predict the mean life-cycle cost of automatic diagnostic systems, including the mean cost of imperfections of such systems. An efficient algorithm for computing global reliability of a network. S. P. JAIN and KRISHNA GOPAL. IEEE Trans. Reliab. 37(5), 488 (December 1988). Global reliability of a network is defined. It is evaluated using spanning trees of the network graph. An algorithm for generating spanning trees (termed, appended spanning trees) which are mutually disjoint is proposed. Each appended spanning tree represents a probability term in final global reliability expression. The algorithm thus directly gives global reliability of a network. It is illustrated with an example. The algorithm is fast, requires very little memory, is adaptable to multiprocessors, and can be terminated at an appropriate stage for an approximate value of global reliability.
Distribntion of residual system-life after partial failures. JANUSZKARPINSKI. IEEE Trans. Reliab. 37(5), 539 (December 1988). This paper presents a general method to determine the distribution of residual system life (RSL) of a coherent system after some partial failures. The RSL begins once all the system components of at least one member of the well-defined set of residual life sets have failed. The approach is based on the knowledge of a special distribution of component lives and system life. It is general with respect to statistical dependence of system component states, unless cold standby is included, It can be applied to any coherent system and can be useful for solving problems of safety forecasts for nuclear power plants, chemical systems, and other potentially dangerous (environmentally) systems. A computer program has been written that permits practical application of the method. The process of determining the distribution of the RSL is generally useful for theoreticians. Analytic and numerical examples of the method are included. Qualitative properties of profit-making k-out-of-n systems subject to two kinds of failures. RAAJKUMARSAH and JOSEPH E. ST1GLITZ. IEEE Trans. Reliab. 37(5), 5i5 (December 1988). This paper derives several properties of the optimal k-out-of-n systems where: I) the i.i.d, components can be, with a pre-specified frequency, in one of two possible modes, 2) components are subject to failures in each of the two modes, and 3) the costs of two kinds of system failures are not necessarily the same. A characterization of the optimal k which maximizes the mean system-profit is obtained (a special case of this optimization criterion is the maximization of system reliability). We show how one can predict, based directly on the parameters of the system, whether the optimal k is smaller or larger than ~n. Also, the directions of change in the optimal k resulting from changes in system parameters are ascertained. A sub-class of our formulation and results corresponds to the case examined in the literature in which the optimal k is chosen to maximize the system's reliability. The phoenix of functional test. STEPHEN F. SCHEIBER, TesI Measure. World 57 (February 1989). The re-emergence of functional testing has renewed clamor to solve the problems that led to its fall from grace.
4. M I C R O E L E C T R O N I C S - - G E N E R A L Hazardous waste control: reducing, recycling and reacting. KATHLEEN M. KEARNEY. Semicond. Int. 78 (October 1988). The semiconductor industry responds to regulations concerning the disposal of hazardous waste. Application specific LSIs for specialized and short-life products enjoy an expanding market. JEE (Japan) 28 (January 1989). As the miniaturization and efficiency of electronic applicances advance, the gate array market for custommade LSIs for specialized and electronic products with short lifespans is expanding rapidly. Although not as dramatic as the DRAM market, the demand for application-specific integrated circuits (ASICs) is steadily increasing. The biggest demand is for gate arrays. Although ASIC production is a small percentage of total IC output, as lifecycles of electrical products shorten, it is expected that the ASIC market will grow. As gate array technology advances, the improvements in CAD tools that require gate arrays will occur very quickly. In addition, advances in designer expertise are expected. New testing devices are responding to higher performance in megabit age. JUNJI NISHIMURA. JEE (Japan) 96 (January 1989). The main issues encountered in testing LSI memories in the megabit age are how to cope with time constraints as
the size of memory increases and how to respond to the high-speed devices. Two memory testers, the T5361, which is equipped with two PG, TG and VRAM emulators for operation at 60 MHz, and the T5331P for testing large-scale high speed memories of lM-bit and 4M-bit DR~Ms for operation at 30 MHz, have been developed by Advantest Corp. This article explains these two memory testers. Optics and electronics are living together. JUN SHIBAIA and TAKAO KAJIWARA. IEEE Spectrum 34 (February 1989). Compound-semiconductor ICs, now reaching the market, offer compact, performance-enhancing alternatives to conventional circuits in fiber communication systems, Microcircuit Engineering '88. A report on the 14th International Conference on microfithography and related sectors, held from September 20 to 22, 1988 in Vienna. D. S~SC~KA. Feinwerktechnik & Messtechnik 97(1-2), 39 (1989). (In German.) The conference, which this time had been organized by the Erwin Schr6dinger Gesellschaft ffir Mikrowissenschaften in connection with the Austrian Ministry of Science and Research, gave over 300 scientists from all over the world the opportunity tO discuss the most recent developments and trends on the sector of microstructure technology. The scientific program was subdivided
World Abstracts on Microelectronics and Reliability into 12 areas with 86 lectures and a presentation of posters with 59 contributions. Research and technology in microelectronies. J. DANNEELS, M. RAHIER and A. MOZER. Elect. Commun. 62(3/4), 352 (1988). Microelectronics technology is the key to the development of increasingly complex telecommunication products. Alcatel maintains a strong research activity in this area with the aim of providing an advanced design methodology and tools for the development of "VLSI systems on silicon".
. MICROELECTRONICS--DESIGN Research reveals differences in coating effects on die stress. FEREYDOUN SHORAKA, CHARLES A. GEALER and ERIC BETTEZ. Semiconductor Int. l l0 (October 1988). Finite element and piezo stress analyses provide practical information on silicone- and polyimide-based die coatings. Application of a two-layer planarization process to VLSI intermetal dielectric and trench isolation processes. D. J. SHELDON, C. W. GRUENSCHLAEGER, L. KAMMERDINER, N. B. HENIS, P. KELLEHER, and J. D. HAYDEN. IEEE Trans. Semicond. Manufact. 1(4), 140 (1988), The application of a novel planarization process using a sacrificial fill layer of photoresist is presented. The process is shown to solve the planarization problems encountered in both intermetal dielectric for a 1.2 ,am 265K SRAM technology and trench isolation for a 0.8-/~m 1M SRAM technology. The process is a simple extension of the standard dielectric etch-back scheme. A discussion of how to precisely quantify circuit planarization using well-known techniques is also presented. This information can then be adapted for statistical quality control purposes.
VLSI: linking design and manufacturing. ANDRZEJ J. STROJWAS and STEPHEN W. DIRECTOR. IEEE Spectrum 24 (October 1988). New CAD tools use data on process parameters and device geometries to predict the characteristics and their statistical distributions, as well as the yields, of complex chips. Sputtering under ultrahigh vacuum environment. G. PE'fER, J. A. KOPRIO and R. SLEPICKA. Vacuum 38(8-10), 795 (1988). An ultrahigh vacuum sputter deposition plant with three sputter targets and a load lock facility for up to 3" wafers is described below. The reasons for transferring such a process into an ultrahigh vacuum plant are explained. The paper concentrates on the method. Some results for Si, W and Ti are presented and compared with results from the literature obtained under high vacuum conditions. Polyimide enables high lead count TAB. IVANAMILOSEVIC, ANDRE PERRET, EWALD LOSERT and PETER SCHLENKRICH. Semicond. Int. 122 (October 1988). Photosensitive polyimide is the key change in our straight wall bumping process for 100 pm pitch, or better, TAB. Change your surfactant formula and use etch baths for a week, KHALID M. SHAH, PENNY MIKKELSEN and WILLIAM CUMMINGS. Semiconductor Int. 132 (October 1988). By altering the ratio of ingredients in surfactant formulations in a filtered etch bath, you can increase their effectiveness. Robotic systems enhance manufacturing efficiency. ANN CHESTNUT, PETER H. SINGER and KATHLEEEN KEARNEY. Semiconductor Int. 58 (October 1988). Automation can help you reduce contamination while enhancing safety, process control and process flexibility.
197
Unusual electron beam effects in the GaAs (100)]Ci 2 system. S. M. MOKLER and P. R. WATSON. Solid St. Commun. 70(4), 415 (1989). We find that chlorine adsorbed on a (1 × 1) GaAs(100) surface is very sensitive to electron-induced desorption. Loss of chlorine appears to occur via at least one fast, and one slow, route with very different cross-sections. Change in the Ga Auger signal indicate that significant Ga-C1 interactions occur during adsorption and electroninduced desorption.
AND
CONSTRUCTION
Dry etch development for silicon processing within a teaching institution. M. A. CARTER. Vacuum 38(8-10), 873 (1988). Reactive ion etching for SiO 2 and for A1/l% Si is described where the requirement is for reliable but low volume processing. The effects of process parameters for one particular system have been investigated. Thermal characterization of a 149-lead VLSI package with heatsink. PAUL B. WESLING. IEEE Trans. Comp. Hybrids Manufact. Tech. 11(4), 512 (December 1988), High power ECL circuits in large pin-grid array (PGA) packages must be optimized for thermal dissipation in order to operate with high reliability in computer applications. In this paper, the steady-state and dynamic thermal characteristics of a 149lead hermetic PGA package are studied, with focus on three different configurations of a stacked-fin heatsink and on two types of fillers for the epoxy heatsink attach adhesive. The package described has high thermal performance in an air-cooled regime. Data are presented showing thermal resistance from junction to ambient as a function of number of heatsink fins and composition of heatsink-attach epoxy. At nominal conditions, thermal resistance from junction to ambient, 0~, of the selected 5-fin heatsink and aluminumfilled epoxy adhesive is less than 6°C/W at an airflow of 2.5 m/s (500 linear ft/min). Also discussed is the junction-to-case thermal resistance, measured per SEMI Standard G30-86. A value of 2.1°C/W was measured for the package. Air bridge and via hole technology for GaAs based microwave devices. Microelect. J. 19(5), 23 (1988). This paper describes the process parameter dependence of air bridges and via holes of different dimensions for GaAs based microwave devices and ICs. Process conditions and technologically feasible optimum dimensions of the air bridges for circuit layout are suggested. A wet etching technique for the formation of extremely small (15 × 15 micron) via holes is also described. New Mnllite ceramic packages and substrates. MICHIO HORIUCHI, KIHOU MIZUSHIMA, YUKIHARUTAKEUCHI and SmN-ICm WAKABAVASm. IEEE Trans. Comp. Hybrids Manufact. Tech. 11(4), 439 (December 1988). Recent VLSI packaging technology requires high propagation speed, high wiring density, and high thermal dissipation. In order to achieve these requirements, ceramic packages need to have a low thermal expansion coefficient, a low dielectric constant, and high thermal conductivity. For these purposes, new mullite ceramics have been developed. The advantages and characteristics of the new mullites are as follows; (1) Low dielectric constants (5.4--7.3 at 1 MHz), favorable for the high propagation speed. (2) Low thermal expansion coefficients (3.0-4.5× 10 6/°C), which permit the direct attachment of large silicon chips. (3) Higher mechanical strength (2~31 kg/min 2) than that of old mullite ceramics.
World Abstracts on Microelectronics and Reliability
rate also increases, drops suddenly at one cycle, then increases again. We discuss two reasonable industrial explanations of such unusual behavior. Measures of testability for automatic diagnostic systems. NAEL A. E. ALY and ADEL A. ALY. IEEE Trans. Reliab. 37(5), 531 (December 1988). This paper presents as investigation into the evaluation models of automatic diagnostic systems taking into consideration their imperfections such as failure to diagnose, incorrect isolation, false alarms, and can-not duplicate. Three measures of effectiveness are developed that enable the decision maker to assess accurately the real capability of the diagnostic system, and to evaluate and compare the performance of alternative automatic diagnostic systems based on their mean life-cycle cost. Analytic procedures for using these measures are developed, and an example is presented. Our conclusions are: • The capability and performance of automatic diagnostic systems can be assessed using three measures of effectiveness: false removal (7 error), failure to diagnose (fl error), and false alarm correction (7)- The 7 error represents problems that arise from false alarms, the fl error measures the capability of correct diagnosis, and y measures the ability of the diagnostic system to correct its actions after indicating a false alarm. These measures show the accuracy and precision of the diagnostic system and cover its imperfections. • The three measures of effectiveness can be used to predict the mean life-cycle cost of automatic diagnostic systems, including the mean cost of imperfections of such systems. An efficient algorithm for computing global reliability of a network. S. P. JAIN and KRISHNA GOPAL. IEEE Trans. Reliab. 37(5), 488 (December 1988). Global reliability of a network is defined. It is evaluated using spanning trees of the network graph. An algorithm for generating spanning trees (termed, appended spanning trees) which are mutually disjoint is proposed. Each appended spanning tree represents a probability term in final global reliability expression. The algorithm thus directly gives global reliability of a network. It is illustrated with an example. The algorithm is fast, requires very little memory, is adaptable to multiprocessors, and can be terminated at an appropriate stage for an approximate value of global reliability.
Distribntion of residual system-life after partial failures. JANUSZKARPINSKI. IEEE Trans. Reliab. 37(5), 539 (December 1988). This paper presents a general method to determine the distribution of residual system life (RSL) of a coherent system after some partial failures. The RSL begins once all the system components of at least one member of the well-defined set of residual life sets have failed. The approach is based on the knowledge of a special distribution of component lives and system life. It is general with respect to statistical dependence of system component states, unless cold standby is included, It can be applied to any coherent system and can be useful for solving problems of safety forecasts for nuclear power plants, chemical systems, and other potentially dangerous (environmentally) systems. A computer program has been written that permits practical application of the method. The process of determining the distribution of the RSL is generally useful for theoreticians. Analytic and numerical examples of the method are included. Qualitative properties of profit-making k-out-of-n systems subject to two kinds of failures. RAAJKUMARSAH and JOSEPH E. ST1GLITZ. IEEE Trans. Reliab. 37(5), 5i5 (December 1988). This paper derives several properties of the optimal k-out-of-n systems where: I) the i.i.d, components can be, with a pre-specified frequency, in one of two possible modes, 2) components are subject to failures in each of the two modes, and 3) the costs of two kinds of system failures are not necessarily the same. A characterization of the optimal k which maximizes the mean system-profit is obtained (a special case of this optimization criterion is the maximization of system reliability). We show how one can predict, based directly on the parameters of the system, whether the optimal k is smaller or larger than ~n. Also, the directions of change in the optimal k resulting from changes in system parameters are ascertained. A sub-class of our formulation and results corresponds to the case examined in the literature in which the optimal k is chosen to maximize the system's reliability. The phoenix of functional test. STEPHEN F. SCHEIBER, TesI Measure. World 57 (February 1989). The re-emergence of functional testing has renewed clamor to solve the problems that led to its fall from grace.
4. M I C R O E L E C T R O N I C S - - G E N E R A L Hazardous waste control: reducing, recycling and reacting. KATHLEEN M. KEARNEY. Semicond. Int. 78 (October 1988). The semiconductor industry responds to regulations concerning the disposal of hazardous waste. Application specific LSIs for specialized and short-life products enjoy an expanding market. JEE (Japan) 28 (January 1989). As the miniaturization and efficiency of electronic applicances advance, the gate array market for custommade LSIs for specialized and electronic products with short lifespans is expanding rapidly. Although not as dramatic as the DRAM market, the demand for application-specific integrated circuits (ASICs) is steadily increasing. The biggest demand is for gate arrays. Although ASIC production is a small percentage of total IC output, as lifecycles of electrical products shorten, it is expected that the ASIC market will grow. As gate array technology advances, the improvements in CAD tools that require gate arrays will occur very quickly. In addition, advances in designer expertise are expected. New testing devices are responding to higher performance in megabit age. JUNJI NISHIMURA. JEE (Japan) 96 (January 1989). The main issues encountered in testing LSI memories in the megabit age are how to cope with time constraints as
the size of memory increases and how to respond to the high-speed devices. Two memory testers, the T5361, which is equipped with two PG, TG and VRAM emulators for operation at 60 MHz, and the T5331P for testing large-scale high speed memories of lM-bit and 4M-bit DR~Ms for operation at 30 MHz, have been developed by Advantest Corp. This article explains these two memory testers. Optics and electronics are living together. JUN SHIBAIA and TAKAO KAJIWARA. IEEE Spectrum 34 (February 1989). Compound-semiconductor ICs, now reaching the market, offer compact, performance-enhancing alternatives to conventional circuits in fiber communication systems, Microcircuit Engineering '88. A report on the 14th International Conference on microfithography and related sectors, held from September 20 to 22, 1988 in Vienna. D. S~SC~KA. Feinwerktechnik & Messtechnik 97(1-2), 39 (1989). (In German.) The conference, which this time had been organized by the Erwin Schr6dinger Gesellschaft ffir Mikrowissenschaften in connection with the Austrian Ministry of Science and Research, gave over 300 scientists from all over the world the opportunity tO discuss the most recent developments and trends on the sector of microstructure technology. The scientific program was subdivided
World Abstracts on Microelectronics and Reliability into 12 areas with 86 lectures and a presentation of posters with 59 contributions. Research and technology in microelectronies. J. DANNEELS, M. RAHIER and A. MOZER. Elect. Commun. 62(3/4), 352 (1988). Microelectronics technology is the key to the development of increasingly complex telecommunication products. Alcatel maintains a strong research activity in this area with the aim of providing an advanced design methodology and tools for the development of "VLSI systems on silicon".
. MICROELECTRONICS--DESIGN Research reveals differences in coating effects on die stress. FEREYDOUN SHORAKA, CHARLES A. GEALER and ERIC BETTEZ. Semiconductor Int. l l0 (October 1988). Finite element and piezo stress analyses provide practical information on silicone- and polyimide-based die coatings. Application of a two-layer planarization process to VLSI intermetal dielectric and trench isolation processes. D. J. SHELDON, C. W. GRUENSCHLAEGER, L. KAMMERDINER, N. B. HENIS, P. KELLEHER, and J. D. HAYDEN. IEEE Trans. Semicond. Manufact. 1(4), 140 (1988), The application of a novel planarization process using a sacrificial fill layer of photoresist is presented. The process is shown to solve the planarization problems encountered in both intermetal dielectric for a 1.2 ,am 265K SRAM technology and trench isolation for a 0.8-/~m 1M SRAM technology. The process is a simple extension of the standard dielectric etch-back scheme. A discussion of how to precisely quantify circuit planarization using well-known techniques is also presented. This information can then be adapted for statistical quality control purposes.
VLSI: linking design and manufacturing. ANDRZEJ J. STROJWAS and STEPHEN W. DIRECTOR. IEEE Spectrum 24 (October 1988). New CAD tools use data on process parameters and device geometries to predict the characteristics and their statistical distributions, as well as the yields, of complex chips. Sputtering under ultrahigh vacuum environment. G. PE'fER, J. A. KOPRIO and R. SLEPICKA. Vacuum 38(8-10), 795 (1988). An ultrahigh vacuum sputter deposition plant with three sputter targets and a load lock facility for up to 3" wafers is described below. The reasons for transferring such a process into an ultrahigh vacuum plant are explained. The paper concentrates on the method. Some results for Si, W and Ti are presented and compared with results from the literature obtained under high vacuum conditions. Polyimide enables high lead count TAB. IVANAMILOSEVIC, ANDRE PERRET, EWALD LOSERT and PETER SCHLENKRICH. Semicond. Int. 122 (October 1988). Photosensitive polyimide is the key change in our straight wall bumping process for 100 pm pitch, or better, TAB. Change your surfactant formula and use etch baths for a week, KHALID M. SHAH, PENNY MIKKELSEN and WILLIAM CUMMINGS. Semiconductor Int. 132 (October 1988). By altering the ratio of ingredients in surfactant formulations in a filtered etch bath, you can increase their effectiveness. Robotic systems enhance manufacturing efficiency. ANN CHESTNUT, PETER H. SINGER and KATHLEEEN KEARNEY. Semiconductor Int. 58 (October 1988). Automation can help you reduce contamination while enhancing safety, process control and process flexibility.
197
Unusual electron beam effects in the GaAs (100)]Ci 2 system. S. M. MOKLER and P. R. WATSON. Solid St. Commun. 70(4), 415 (1989). We find that chlorine adsorbed on a (1 × 1) GaAs(100) surface is very sensitive to electron-induced desorption. Loss of chlorine appears to occur via at least one fast, and one slow, route with very different cross-sections. Change in the Ga Auger signal indicate that significant Ga-C1 interactions occur during adsorption and electroninduced desorption.
AND
CONSTRUCTION
Dry etch development for silicon processing within a teaching institution. M. A. CARTER. Vacuum 38(8-10), 873 (1988). Reactive ion etching for SiO 2 and for A1/l% Si is described where the requirement is for reliable but low volume processing. The effects of process parameters for one particular system have been investigated. Thermal characterization of a 149-lead VLSI package with heatsink. PAUL B. WESLING. IEEE Trans. Comp. Hybrids Manufact. Tech. 11(4), 512 (December 1988), High power ECL circuits in large pin-grid array (PGA) packages must be optimized for thermal dissipation in order to operate with high reliability in computer applications. In this paper, the steady-state and dynamic thermal characteristics of a 149lead hermetic PGA package are studied, with focus on three different configurations of a stacked-fin heatsink and on two types of fillers for the epoxy heatsink attach adhesive. The package described has high thermal performance in an air-cooled regime. Data are presented showing thermal resistance from junction to ambient as a function of number of heatsink fins and composition of heatsink-attach epoxy. At nominal conditions, thermal resistance from junction to ambient, 0~, of the selected 5-fin heatsink and aluminumfilled epoxy adhesive is less than 6°C/W at an airflow of 2.5 m/s (500 linear ft/min). Also discussed is the junction-to-case thermal resistance, measured per SEMI Standard G30-86. A value of 2.1°C/W was measured for the package. Air bridge and via hole technology for GaAs based microwave devices. Microelect. J. 19(5), 23 (1988). This paper describes the process parameter dependence of air bridges and via holes of different dimensions for GaAs based microwave devices and ICs. Process conditions and technologically feasible optimum dimensions of the air bridges for circuit layout are suggested. A wet etching technique for the formation of extremely small (15 × 15 micron) via holes is also described. New Mnllite ceramic packages and substrates. MICHIO HORIUCHI, KIHOU MIZUSHIMA, YUKIHARUTAKEUCHI and SmN-ICm WAKABAVASm. IEEE Trans. Comp. Hybrids Manufact. Tech. 11(4), 439 (December 1988). Recent VLSI packaging technology requires high propagation speed, high wiring density, and high thermal dissipation. In order to achieve these requirements, ceramic packages need to have a low thermal expansion coefficient, a low dielectric constant, and high thermal conductivity. For these purposes, new mullite ceramics have been developed. The advantages and characteristics of the new mullites are as follows; (1) Low dielectric constants (5.4--7.3 at 1 MHz), favorable for the high propagation speed. (2) Low thermal expansion coefficients (3.0-4.5× 10 6/°C), which permit the direct attachment of large silicon chips. (3) Higher mechanical strength (2~31 kg/min 2) than that of old mullite ceramics.