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World Abstracts on Microelectronics and Reliability 8. T H I C K -
AND
THIN-FILM AND
COMPONENTS,
HYBRID
CIRCUITS
MATERIALS
Conduction Processes in thick film resistors. Part 1. M. P. ANS[iLL. Electrocomponem Sci. Tectmol. 3, 131 (1976). The structures of three families of thick film resistors have been investigated by scanning electron microscopy and electron probe micro-analysis. The two principal components of the resistive glazes, that is the conducting pigment and the glassy binder, have been identified in each case. The pigments were found to be simple or ternary oxides of the Pt transition metal group and Pd/PdO/Ag alloys. The glassy binders were based on lead borosilicate glasses. A model for the electronic conduction processes through the glass and pigments is proposed on the basis of the observed physical structures, the measured electrical properties of resistors and the properties of the component resistor materials. Part I of the total paper is concerned with identifying the phases in various Thick Film Resistors and Part II considers the conduction processes that are appropriate. Conduction processes in thick film resistors. Part I1. M. P. ANSELL. Electrocomponent Sci. Technol. 3, 141 (1976). The structures of three families of thick film resistors have been investigated by scanning electron microscopy and electron probe micro-analysis. The two principal components of the resistive glazes, that is the conducting pigment and the glassy binder, have been identified in each case. The pigments were found to be simple or ternary oxides of the Pt transition metal group and Pd/PdO/Ag alloys. The glassy binders were based on lead borosilicate glasses. A model for the electronic conduction processes through the glass and pigments is proposed on the basis of the observed physical structures, the measured electrical properties of resistors and the properties of the component resistor materials. Part I of the total paper is concerned with identifying the phases in various thick film resistors and Part II considers the conduction processes that are applicable. Design and manufacture of modem mechanical vacuum pumps. N. S. HARRISand L. BUDGEN. Vacuum 26 (12), 525. This paper will cover the design and manufacturing aspects of rotary vane, rotary piston and mechanical booster pumps. An historical approach to the development of the rotary vane pump will be made to emphasise design improvements in areas such as exhaust valves and anti "suckback" devices. Other developments such as the design of better balanced pumps will be discussed. Noise is another problem which has largely been overcome. The advantages of the introduction of hydrokinetic drive for mechanical booster pumps will be made and finally the manufacturing techniques of modern pumps will be looked at with reference to the use of numerical control machine. Vacuum evaporation from finite surfaces. S. H. ALGIE. Vacuum 26 (12), 503. It is known that the evaporation rate is equal to the rate of phase transition only when the evaporating surface is small or when a condensing surface is placed very close to the evaporating surface. This paper describes a quantitative theory which predicts the rate of evaporation from a finite surface into a vacuum in the absence of such a condenser or other nearby surfaces. The predictions of the theory for finite surfaces have been confirmed by comparison with experimental data reported in the literature and, in the limiting case of an infinite surface, with the predictions of a previous theoretical study. A program to predict the resistance of trimmed film resistors. P. L. MORAN and C. K. MAITI. Electrocomponent Sci. Technol. 3, 153 (1976). A program that numerically models
laser trimmed film resistors is described. From this nrodel it is possible to predict the resistance, sensitivity of resistance to trim cuts and the magnitude of local "'hot spots". An example of the use of the program is given. The hybrid integration of a multistage active bandpass filter/ amplifier. K. B. Cook JR., D. V. KERYSJR., H. TROY NAGI£ JR., T. D. SLAGH and V. W. Ruw~. IEEE Trans. Parts, Hybrids, Packayiny PHP-12 (4), 336 (December 1976). This paper describes the fabrication, characterization, and analysis of a hybrid microcircuit to be used as a signal amplifier and conditioner for an IR tracking system The entire circuit is integrated on a 1 x 2-in alumina substrate using thick-film resistors and conductors, some chip resistors in critical locations, chip capacitors, and monolithic integrated-circuit (IC) operational-amplifier (op-amp) chips. Fig. 1 shows a block diagram of the entire circuit. The transfer functions of each of the stages is derived. The predicted gain peak and the shape of the measured bandpass agree well with experimental results. The computer simulation using an op-amp "macromodcl" gives results very closely resembling the measured bandpass, and underscores the utility of computer circuit simulations in IC development. Stability and hybrid layou! considerations are discussed. The noise figure is measured as a function of frequency for the given system source impedance of 5 MQ and also for 0.5 M ~ to indicate the dependence of the noise figure on source resistance. The dominant sources of noise in the amplifier/filter and low-noise design considerations are discussed. Evaluation of thick film conductors. M. V. COLEMAN. Proc. lnterm,pcon. Microelectron. 1976. Brighton. p. 1 (October 19 21, 1976). The conductor is probably the most critical part of a thick film hybrid circuit being required to fulfil a variety of roles. Not only is a high conductivity, high adhesion, stable material required, but the conductor may be called upon to terminate other thick film components without adverse interaction. Furthermore, wire bond, epoxy resin and solder terminations have to be made to these conductors such joints must retain their strenglh over ten or more years at elevated temperatures. An examination of the problems associated with the production of high reliability thick film conductors has been made over recent years at STL. The effects of both processing conditions and substrate type on conductor parameters have been examined and their effects on terminations determined. An attempt has been made to understand the mechanisms involved by detailed analysis of the materials used. High voltage stable thick film resistors. P. F. GARCIA, S. E. CHAMP, J. R. LARRY and R. B. FLIPPEN. Proc. Internepcon. Microelectron. '76. Brighton. p. 22 (October 19 21, 1976). The materials parameters responsible for achieving high voltage stability in high resistivity thick film resistor composites were explored through measurement of conductance and temperature coefficient of resistance (TCR) to low temperature. A strong temperature dependence of the electric field-enhanced conductance and large negative TCR's at low temperature are correlated with stability at high voltage. These properties suggest a resistor model with semi-continuous conductive phase regions linked by a semiconducting intergranular phase. A barrier between conducting and semiconducting regions gives rise to the field-enhanced conductance. The more uniform distribution of voltage stress for this configuration is responsible for high voltage stability.
World Abstracts on Microelectronics and Reliability 8. T H I C K -
AND
THIN-FILM AND
COMPONENTS,
HYBRID
CIRCUITS
MATERIALS
Conduction Processes in thick film resistors. Part 1. M. P. ANS[iLL. Electrocomponem Sci. Tectmol. 3, 131 (1976). The structures of three families of thick film resistors have been investigated by scanning electron microscopy and electron probe micro-analysis. The two principal components of the resistive glazes, that is the conducting pigment and the glassy binder, have been identified in each case. The pigments were found to be simple or ternary oxides of the Pt transition metal group and Pd/PdO/Ag alloys. The glassy binders were based on lead borosilicate glasses. A model for the electronic conduction processes through the glass and pigments is proposed on the basis of the observed physical structures, the measured electrical properties of resistors and the properties of the component resistor materials. Part I of the total paper is concerned with identifying the phases in various Thick Film Resistors and Part II considers the conduction processes that are appropriate. Conduction processes in thick film resistors. Part I1. M. P. ANSELL. Electrocomponent Sci. Technol. 3, 141 (1976). The structures of three families of thick film resistors have been investigated by scanning electron microscopy and electron probe micro-analysis. The two principal components of the resistive glazes, that is the conducting pigment and the glassy binder, have been identified in each case. The pigments were found to be simple or ternary oxides of the Pt transition metal group and Pd/PdO/Ag alloys. The glassy binders were based on lead borosilicate glasses. A model for the electronic conduction processes through the glass and pigments is proposed on the basis of the observed physical structures, the measured electrical properties of resistors and the properties of the component resistor materials. Part I of the total paper is concerned with identifying the phases in various thick film resistors and Part II considers the conduction processes that are applicable. Design and manufacture of modem mechanical vacuum pumps. N. S. HARRISand L. BUDGEN. Vacuum 26 (12), 525. This paper will cover the design and manufacturing aspects of rotary vane, rotary piston and mechanical booster pumps. An historical approach to the development of the rotary vane pump will be made to emphasise design improvements in areas such as exhaust valves and anti "suckback" devices. Other developments such as the design of better balanced pumps will be discussed. Noise is another problem which has largely been overcome. The advantages of the introduction of hydrokinetic drive for mechanical booster pumps will be made and finally the manufacturing techniques of modern pumps will be looked at with reference to the use of numerical control machine. Vacuum evaporation from finite surfaces. S. H. ALGIE. Vacuum 26 (12), 503. It is known that the evaporation rate is equal to the rate of phase transition only when the evaporating surface is small or when a condensing surface is placed very close to the evaporating surface. This paper describes a quantitative theory which predicts the rate of evaporation from a finite surface into a vacuum in the absence of such a condenser or other nearby surfaces. The predictions of the theory for finite surfaces have been confirmed by comparison with experimental data reported in the literature and, in the limiting case of an infinite surface, with the predictions of a previous theoretical study. A program to predict the resistance of trimmed film resistors. P. L. MORAN and C. K. MAITI. Electrocomponent Sci. Technol. 3, 153 (1976). A program that numerically models
laser trimmed film resistors is described. From this nrodel it is possible to predict the resistance, sensitivity of resistance to trim cuts and the magnitude of local "'hot spots". An example of the use of the program is given. The hybrid integration of a multistage active bandpass filter/ amplifier. K. B. Cook JR., D. V. KERYSJR., H. TROY NAGI£ JR., T. D. SLAGH and V. W. Ruw~. IEEE Trans. Parts, Hybrids, Packayiny PHP-12 (4), 336 (December 1976). This paper describes the fabrication, characterization, and analysis of a hybrid microcircuit to be used as a signal amplifier and conditioner for an IR tracking system The entire circuit is integrated on a 1 x 2-in alumina substrate using thick-film resistors and conductors, some chip resistors in critical locations, chip capacitors, and monolithic integrated-circuit (IC) operational-amplifier (op-amp) chips. Fig. 1 shows a block diagram of the entire circuit. The transfer functions of each of the stages is derived. The predicted gain peak and the shape of the measured bandpass agree well with experimental results. The computer simulation using an op-amp "macromodcl" gives results very closely resembling the measured bandpass, and underscores the utility of computer circuit simulations in IC development. Stability and hybrid layou! considerations are discussed. The noise figure is measured as a function of frequency for the given system source impedance of 5 MQ and also for 0.5 M ~ to indicate the dependence of the noise figure on source resistance. The dominant sources of noise in the amplifier/filter and low-noise design considerations are discussed. Evaluation of thick film conductors. M. V. COLEMAN. Proc. lnterm,pcon. Microelectron. 1976. Brighton. p. 1 (October 19 21, 1976). The conductor is probably the most critical part of a thick film hybrid circuit being required to fulfil a variety of roles. Not only is a high conductivity, high adhesion, stable material required, but the conductor may be called upon to terminate other thick film components without adverse interaction. Furthermore, wire bond, epoxy resin and solder terminations have to be made to these conductors such joints must retain their strenglh over ten or more years at elevated temperatures. An examination of the problems associated with the production of high reliability thick film conductors has been made over recent years at STL. The effects of both processing conditions and substrate type on conductor parameters have been examined and their effects on terminations determined. An attempt has been made to understand the mechanisms involved by detailed analysis of the materials used. High voltage stable thick film resistors. P. F. GARCIA, S. E. CHAMP, J. R. LARRY and R. B. FLIPPEN. Proc. Internepcon. Microelectron. '76. Brighton. p. 22 (October 19 21, 1976). The materials parameters responsible for achieving high voltage stability in high resistivity thick film resistor composites were explored through measurement of conductance and temperature coefficient of resistance (TCR) to low temperature. A strong temperature dependence of the electric field-enhanced conductance and large negative TCR's at low temperature are correlated with stability at high voltage. These properties suggest a resistor model with semi-continuous conductive phase regions linked by a semiconducting intergranular phase. A barrier between conducting and semiconducting regions gives rise to the field-enhanced conductance. The more uniform distribution of voltage stress for this configuration is responsible for high voltage stability.