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Improved techniques for proximity mask alignment
World Abstracts on Microelectronics and Reliability
527
photosensitive film and for etching and cleaning has been neglected on the premise that the final ultra-pure water rinse will remove all traces of the chemicals used. In principle this is true for the impurities soluble in water but it is not true for the insoluble impurities. Such insoluble impurities constitute the particulate matter found in the processing chemicals used by the semiconductor manufacturers. In the experience of Micro-Image Technology the pure chemicals supplied by major chemical manufacturers contain considerable quantities of particulate matter which can be removed by filtration down to 0.2 micron using compatible Millipore absolute membrane filters. Furthermore, the size distribution of the particles conforms to that described by B. Carbonel, the majority being below 1 micron but greater than 0.2 micron. Such particles are susceptible to adsorbtion on the Si or SiO2 surface and cannot easily be removed by rinsing the wafer in water.
hard-surface masks is described. The microprocessor permits simplification of operation so that the process is easily integrated into existing mask inspection facilities relying on the capabilities of typical operators. The stable, reliable TEM-00 mode laser radiation and rectangular image beam shaping optics permit accurate repair to tolerances of less than 1.0 micron with straight edges and negligible damage to the mask substrate. The net result is an improvement in yield by more than a factor of two and consequent equivalent reduction in cost of mask manufacture.
Gang lead bonding integrated circuits. THOMAS ANGELUCCI, SR. Solid-State Tech. p. 21 (July 1976). Performance and cost specifics on the new automated gang bonding techniques are explored. Also included are production characteristics of wire bonding. Tape systems, bond metallurgy, chip fabrication, and gang bonding equipment are discussed and a description of the requirements for each is given. This is followed by an examination of industry trends and effects as they relate to automated gang lead bonding.
NBS program in photomask linewidth measurements.
Polyimide supported micro-ramps for high density circuit intereonnection. J. J. LICARI,J. E. VARGAand W. A. BAILEY. Solid-State Tech. p. 41 (July 1976). A process has been developed for the batch fabrication of both gold and aluminum "micro-ramp" crossover networks. The microramps are fully supported with polyimide insulation which is applied by screening. In addition, batch-fabricated precision nichrome resistors have been integrated with the crossover conductor network. The new process solves many of the problems inherent in the original air-gap microbridge process and expands its application to analog microcircuits.
A projection system for inspecting wafers, integrated circuits and photomasks. PAUL ROSENTHAL. Solid-State Tech. p. 85 (April 1976). An optical device for the inspection of IC's and photomasks by means of projection is described. Observing the image on an opaque screen rather than viewing through a microscope eases eye-strain during the inspection procedure.
Improved techniques for proximity mask alignment. K. G. CLARK and K. OKUTSU. Solid-State Tech. p. 79 (April 1976). A great deal of the new semiconductor business is of LSI and is requiring the semiconductor manufacturer to evaluate systems for increasing device yield and reducing the burden of the photornask making department in producing large quantities of low defect masks. Until recently out of contact mask alignment has been mainly restricted to projection printing due to the very small gaps offered by proximity printers (typically to 10/am) and the need to use hard surface masks. Recent improvement of illumination systems and viewing microscopes have permitted larger separation gaps to be used whilst still obtaining fine line widths in the range of 2.0/~m to 3.0 #m and allowing photomasks of many technologies to be used with proximity mask alignment.
A microprocessor-controlled mask inspection and repair system. ROBERT A. KAPLAN Solid-State Tech. p. 74 (April 1976). A microprocessor-controlled laser tool which permits efficient and accurate repair of opaque defects on
The structure of cleaned and polished (100) GaAs surfaces. B. L. WEISS and H. L. HARTNAGEL. Int. J. Electron. 41, (2), 185 (1976). Results are presented here which show that after cleaning in organic solvents, polishing with Br-methanol solution and etching in HC1, all GaAs samples have a residual thin layer of oxide on their surfaces.
DENNIS A. SWVT. Solid-State Tech. (April 1976). A problem facing the microelectronics industry is that of making accurate dimensional measurements of photomask patterns with the optical microscope, the usual tool for mask inspection. A part of the problem is the absence of calibrated linewidth standards in photomask materials for the critical 1 to 10 #m range. This article discusses the status of a National Bureau of Standards program to develop such standards and to develop the means to identify and control the parameters of optical performance which introduce errors into linewidth measurements.
Present developments in digital logic design. S. L. HURSr. Microclectronics. 7, (4) 27 (1976). A look is taken at the way in which the design of logic networks is currently undertaken, and the proposition put forward that in spite of great sophistication of currently-available integrated-circuit packages a great deal remains to be desired at the basic grass roots logic design stage. The problem is that simple Boolean logic gates and Boolean algebra are not sufficiently powerful to produce more efficient network designs. However present developments of alternative methods of handling the digital data and also logically more powerful gates may gradually influence our ways, and result in the ready design of more efficient and compact logic networks.
Temperature characteristics of MNOS transistors. A. N. ANDREEVA and L. I. POPOVA. Microelectronics 7, (4), 23 (1976). MNOS transistors with low threshold voltage and high transconductance have been produced. Variations with temperature in the threshold voltage of MNOS transistors and output voltage of MNOS IC are obtained by calculation, and the results compare closely with those obtained by actual measurements. The temperature characteristics show, that for practical purposes MNOS devices are fairly independent of temperature over the range from 30°C to 125°C,
A circuit for high-speed carry propagation in I.S.I.-F.E.T. technology. T. LAMDAN and M. AHARON. The Radio and Electronic Engineer 46, (7), 337 (July 1976). A circuit configuration for high-speed carry propagation employing serial floating field effect transistors in parallel digital adders is presented. Circuit parameters affecting the performance of the suggested configuration are evaluated. Results of comparisons with alternative m.s.i, and l.s.i, adder circuits are given and show that the present suggestion is superior to the alternatives.
Functional modelling of non-volatile MOS memory devices. H. C. CARD and M. I. ELMASRY. Solid-State Electron. 19,
527
photosensitive film and for etching and cleaning has been neglected on the premise that the final ultra-pure water rinse will remove all traces of the chemicals used. In principle this is true for the impurities soluble in water but it is not true for the insoluble impurities. Such insoluble impurities constitute the particulate matter found in the processing chemicals used by the semiconductor manufacturers. In the experience of Micro-Image Technology the pure chemicals supplied by major chemical manufacturers contain considerable quantities of particulate matter which can be removed by filtration down to 0.2 micron using compatible Millipore absolute membrane filters. Furthermore, the size distribution of the particles conforms to that described by B. Carbonel, the majority being below 1 micron but greater than 0.2 micron. Such particles are susceptible to adsorbtion on the Si or SiO2 surface and cannot easily be removed by rinsing the wafer in water.
hard-surface masks is described. The microprocessor permits simplification of operation so that the process is easily integrated into existing mask inspection facilities relying on the capabilities of typical operators. The stable, reliable TEM-00 mode laser radiation and rectangular image beam shaping optics permit accurate repair to tolerances of less than 1.0 micron with straight edges and negligible damage to the mask substrate. The net result is an improvement in yield by more than a factor of two and consequent equivalent reduction in cost of mask manufacture.
Gang lead bonding integrated circuits. THOMAS ANGELUCCI, SR. Solid-State Tech. p. 21 (July 1976). Performance and cost specifics on the new automated gang bonding techniques are explored. Also included are production characteristics of wire bonding. Tape systems, bond metallurgy, chip fabrication, and gang bonding equipment are discussed and a description of the requirements for each is given. This is followed by an examination of industry trends and effects as they relate to automated gang lead bonding.
NBS program in photomask linewidth measurements.
Polyimide supported micro-ramps for high density circuit intereonnection. J. J. LICARI,J. E. VARGAand W. A. BAILEY. Solid-State Tech. p. 41 (July 1976). A process has been developed for the batch fabrication of both gold and aluminum "micro-ramp" crossover networks. The microramps are fully supported with polyimide insulation which is applied by screening. In addition, batch-fabricated precision nichrome resistors have been integrated with the crossover conductor network. The new process solves many of the problems inherent in the original air-gap microbridge process and expands its application to analog microcircuits.
A projection system for inspecting wafers, integrated circuits and photomasks. PAUL ROSENTHAL. Solid-State Tech. p. 85 (April 1976). An optical device for the inspection of IC's and photomasks by means of projection is described. Observing the image on an opaque screen rather than viewing through a microscope eases eye-strain during the inspection procedure.
Improved techniques for proximity mask alignment. K. G. CLARK and K. OKUTSU. Solid-State Tech. p. 79 (April 1976). A great deal of the new semiconductor business is of LSI and is requiring the semiconductor manufacturer to evaluate systems for increasing device yield and reducing the burden of the photornask making department in producing large quantities of low defect masks. Until recently out of contact mask alignment has been mainly restricted to projection printing due to the very small gaps offered by proximity printers (typically to 10/am) and the need to use hard surface masks. Recent improvement of illumination systems and viewing microscopes have permitted larger separation gaps to be used whilst still obtaining fine line widths in the range of 2.0/~m to 3.0 #m and allowing photomasks of many technologies to be used with proximity mask alignment.
A microprocessor-controlled mask inspection and repair system. ROBERT A. KAPLAN Solid-State Tech. p. 74 (April 1976). A microprocessor-controlled laser tool which permits efficient and accurate repair of opaque defects on
The structure of cleaned and polished (100) GaAs surfaces. B. L. WEISS and H. L. HARTNAGEL. Int. J. Electron. 41, (2), 185 (1976). Results are presented here which show that after cleaning in organic solvents, polishing with Br-methanol solution and etching in HC1, all GaAs samples have a residual thin layer of oxide on their surfaces.
DENNIS A. SWVT. Solid-State Tech. (April 1976). A problem facing the microelectronics industry is that of making accurate dimensional measurements of photomask patterns with the optical microscope, the usual tool for mask inspection. A part of the problem is the absence of calibrated linewidth standards in photomask materials for the critical 1 to 10 #m range. This article discusses the status of a National Bureau of Standards program to develop such standards and to develop the means to identify and control the parameters of optical performance which introduce errors into linewidth measurements.
Present developments in digital logic design. S. L. HURSr. Microclectronics. 7, (4) 27 (1976). A look is taken at the way in which the design of logic networks is currently undertaken, and the proposition put forward that in spite of great sophistication of currently-available integrated-circuit packages a great deal remains to be desired at the basic grass roots logic design stage. The problem is that simple Boolean logic gates and Boolean algebra are not sufficiently powerful to produce more efficient network designs. However present developments of alternative methods of handling the digital data and also logically more powerful gates may gradually influence our ways, and result in the ready design of more efficient and compact logic networks.
Temperature characteristics of MNOS transistors. A. N. ANDREEVA and L. I. POPOVA. Microelectronics 7, (4), 23 (1976). MNOS transistors with low threshold voltage and high transconductance have been produced. Variations with temperature in the threshold voltage of MNOS transistors and output voltage of MNOS IC are obtained by calculation, and the results compare closely with those obtained by actual measurements. The temperature characteristics show, that for practical purposes MNOS devices are fairly independent of temperature over the range from 30°C to 125°C,
A circuit for high-speed carry propagation in I.S.I.-F.E.T. technology. T. LAMDAN and M. AHARON. The Radio and Electronic Engineer 46, (7), 337 (July 1976). A circuit configuration for high-speed carry propagation employing serial floating field effect transistors in parallel digital adders is presented. Circuit parameters affecting the performance of the suggested configuration are evaluated. Results of comparisons with alternative m.s.i, and l.s.i, adder circuits are given and show that the present suggestion is superior to the alternatives.
Functional modelling of non-volatile MOS memory devices. H. C. CARD and M. I. ELMASRY. Solid-State Electron. 19,