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A comprehensive sequence for the electron beam exposure system
crystal growth, has made substantial progress in many areas in the last decade. Crystals with a diameter of 125mm have been grown; crystals with smaller diameters have had lengths of 150cm. Uniform resistivity profiles, including the virtual elimination of resistivity striations, can be obtained by neutron-transmutation doping. Micro-defects such as B-pits have been eliminated both in elemental and neutron-transmutation doped crystals. Attemps to improve the high-temperature properties of float-zoned wafers appear promising. In the fabrication of detector-grade silicon requiring very high resistivities, float-zoned material has no peer. The first growth of silicon in space will utilize the principles of float-zoning.
3. Production & Processing Developments in crystal growth from high-temperature solutions HANS J. SCHEEL Prog. Crystal Growth Char., 5, 277 (1982) With the technological advances in the past 12 years, and with the high quality of flux-grown crystals and layers, this crystal-growth technique has become increasingly important. The technological parameters which have to be optimized to achieve large structuaUy perfect crystals, of high purity and free of striations, are: choice of solvent, growth temperature and its control, temperature gradient at and along the growth interface, supersaturation, and hydrodynamics. Top-seeded solution growth and the accelerated crucible rotation technique are the most widely applied techniques for growth of large high-qulity crystals. Ceramic on metal substrates produced by plasma spraying for thick film technology LESZEK GOLONKA and LECH PAWLOWSKI Electrocomponent Sei. Technol. ao, 143 (1983) The arc plasma spraying process was applicd to obtain ceramic coatings on stainless steel substrates. The outer coatings were formed from pure alumina or alumina+2wt.% titania mixture. The nichrome intermediate coating was applicd to increase adhesion of ceramic coating to stainless steel. The X-ray analysis, metallographic and SEM invcstigations of the spraycd coatings were also carried out. The effect of interaction of thick film conductor and resistor compositions was studied. Conductor ink P 202 PdAg and resistor ink DP 1321 were evaluated. The TCR, rcsistance stability were measured as a function of firing cycles. These parameters and the resistivity of sprayed alumina wcre compared with standard 96% alumina substrate characteristics. Serf-consistent theory of diagonal and off-diogonai disorder in the screened impurity band of doped semiconductors N O R B E R T O MAJLIS and ENRIQUE V. ANDA Solid St. Communs 45 (7), 561 (1983) Wc have developed a theory of the impurity band in doped semi-conductors, using a tight-binding basis and a self-consistent treatment to handle the configurational averages. New ingredients in the present calculation are: (1) overlap between different impurity orbitals; (2) simultaneous treatment of diagonal and off-diagonal 44
disorder; (3) inclusion of electron- electron interactions through the substitution of the bare Coulomb impurity potential by a Yukawa potential. The density of states and the position of the Fermi level (for T = 0) are calculated for different impurity concentrations.
4. Testing A comprehensive sequence for the electron beam exlmsure system T E R R E N C E E. Z A V E C Z Solid St. TechnoL, 106 (February 1982) The electron beam exposure system (EBES) currently used for photomask fabrication have been designed to operate to positional accuracies of +-0.031 micron over an address range of 0.20 to 1.00 micron. The tuning, calibration and characterization of these systems has required an exacting and time consuming series of tests. A standard test array, M A R K E T A15, has been developed which enables full system characterization with only a thiry minute master generation time and a four hour analysis. System parameters such as linewidth control, resolution, registration, absolute accuracy and pattern scale accuracy can be determined from a single plate. The tests are composed of a series of exposures designed for analysis under an optical microscope along with a second group requiring reinsertion of the plate into EBES for "selfanalysis". This array can be used as a basis for tuning, monitoring and multiple systems calibration of EBES or EBES-Iike raster scan systems. A discussion of tests and techniques demonstrates how several EBES type systems in Western Electric and Bell Laboratories have been brought into mutual compatibility. ZRM 20 - an electron-beam mask and wafer measuring and inspection system R E I N E R PLONTKE and WERNER LELLE Jena Rev. 2, 76 (1982) The rapid development of microlithography has led to IC chips containing up to I0z active device functions. Simultaneously, silicon wafers have grown in diameter; 150ram wafers are in the offing. Accordingly, the importance of measuring and inspection equipment has increased. In order to maintain uniform quality of the end product and to raise chip yield - essential criteria for economical production - it is imperative that the effects brought about, e.g, by changed process parameters, should be precisely known. Inspection equipments have increasingly been employing the electron beam as growing packing densities have continuously minimized line widths and line spacing on masks and semiconductor wafers down to submicrometre dimensions. Compared to opticalmechanical instruments, electron-beam systems benefit from higher resolving power, greater depth of focus and easier guiding and deflection of the beam. Design for testability- a survey THOMAS W. WILLIAMS and KENNETH P. PARKER Proc. IEEE 71 (1), 98 (1983) This paper discusses the basics of design for testability. A short review of testing is given along with some reasons why one should test. The different techniques of design
3. Production & Processing Developments in crystal growth from high-temperature solutions HANS J. SCHEEL Prog. Crystal Growth Char., 5, 277 (1982) With the technological advances in the past 12 years, and with the high quality of flux-grown crystals and layers, this crystal-growth technique has become increasingly important. The technological parameters which have to be optimized to achieve large structuaUy perfect crystals, of high purity and free of striations, are: choice of solvent, growth temperature and its control, temperature gradient at and along the growth interface, supersaturation, and hydrodynamics. Top-seeded solution growth and the accelerated crucible rotation technique are the most widely applied techniques for growth of large high-qulity crystals. Ceramic on metal substrates produced by plasma spraying for thick film technology LESZEK GOLONKA and LECH PAWLOWSKI Electrocomponent Sei. Technol. ao, 143 (1983) The arc plasma spraying process was applicd to obtain ceramic coatings on stainless steel substrates. The outer coatings were formed from pure alumina or alumina+2wt.% titania mixture. The nichrome intermediate coating was applicd to increase adhesion of ceramic coating to stainless steel. The X-ray analysis, metallographic and SEM invcstigations of the spraycd coatings were also carried out. The effect of interaction of thick film conductor and resistor compositions was studied. Conductor ink P 202 PdAg and resistor ink DP 1321 were evaluated. The TCR, rcsistance stability were measured as a function of firing cycles. These parameters and the resistivity of sprayed alumina wcre compared with standard 96% alumina substrate characteristics. Serf-consistent theory of diagonal and off-diogonai disorder in the screened impurity band of doped semiconductors N O R B E R T O MAJLIS and ENRIQUE V. ANDA Solid St. Communs 45 (7), 561 (1983) Wc have developed a theory of the impurity band in doped semi-conductors, using a tight-binding basis and a self-consistent treatment to handle the configurational averages. New ingredients in the present calculation are: (1) overlap between different impurity orbitals; (2) simultaneous treatment of diagonal and off-diagonal 44
disorder; (3) inclusion of electron- electron interactions through the substitution of the bare Coulomb impurity potential by a Yukawa potential. The density of states and the position of the Fermi level (for T = 0) are calculated for different impurity concentrations.
4. Testing A comprehensive sequence for the electron beam exlmsure system T E R R E N C E E. Z A V E C Z Solid St. TechnoL, 106 (February 1982) The electron beam exposure system (EBES) currently used for photomask fabrication have been designed to operate to positional accuracies of +-0.031 micron over an address range of 0.20 to 1.00 micron. The tuning, calibration and characterization of these systems has required an exacting and time consuming series of tests. A standard test array, M A R K E T A15, has been developed which enables full system characterization with only a thiry minute master generation time and a four hour analysis. System parameters such as linewidth control, resolution, registration, absolute accuracy and pattern scale accuracy can be determined from a single plate. The tests are composed of a series of exposures designed for analysis under an optical microscope along with a second group requiring reinsertion of the plate into EBES for "selfanalysis". This array can be used as a basis for tuning, monitoring and multiple systems calibration of EBES or EBES-Iike raster scan systems. A discussion of tests and techniques demonstrates how several EBES type systems in Western Electric and Bell Laboratories have been brought into mutual compatibility. ZRM 20 - an electron-beam mask and wafer measuring and inspection system R E I N E R PLONTKE and WERNER LELLE Jena Rev. 2, 76 (1982) The rapid development of microlithography has led to IC chips containing up to I0z active device functions. Simultaneously, silicon wafers have grown in diameter; 150ram wafers are in the offing. Accordingly, the importance of measuring and inspection equipment has increased. In order to maintain uniform quality of the end product and to raise chip yield - essential criteria for economical production - it is imperative that the effects brought about, e.g, by changed process parameters, should be precisely known. Inspection equipments have increasingly been employing the electron beam as growing packing densities have continuously minimized line widths and line spacing on masks and semiconductor wafers down to submicrometre dimensions. Compared to opticalmechanical instruments, electron-beam systems benefit from higher resolving power, greater depth of focus and easier guiding and deflection of the beam. Design for testability- a survey THOMAS W. WILLIAMS and KENNETH P. PARKER Proc. IEEE 71 (1), 98 (1983) This paper discusses the basics of design for testability. A short review of testing is given along with some reasons why one should test. The different techniques of design