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1536. An automated electron-beam mask generator
Classified abstracts
1535-l 544
aberration coefficient of 0.5 nm. A lanthanum hexaborlde cathode is 10’ A/cm* sr at employed with a maximum brightness of 1.5 75 kV. The cathode operates satisfactonly at a pressure of 10m6 mm Hg The theoretical minimum beam size for the Instrument 1s 5 A. Transmission scanning electron micrographs with a beam current of 1 /( lo-‘Z-3 x lo-‘2 A Indicates that close to this value IS obtained m practice. A N Broers, J vu’acSci Technol, 10 (6), 1973, 979-982. 33 1535. Range and energy deposition enhancement of a fast electron heam by external electric fields. (USA) The electrode configuratIon m electron-beam prelonized electrlcal discharge pumped molecular gas lasers can be arranged such that the drift field of the pump accelerates the fast electrons which are concurrently scattered. In deslgmng lasers with output pulses beyond the kJ energy level, one uses the drift field to extend the range and to enhance the energy deposition of the fast electron beam. Although scattering and energy loss of electrons penetrating mto matter without an external field is well known, electrical fields of the order of kV cm-’ at atmosphere pressures substantially affect both the range and the energy deposition of the primaries. We report numerlcal results in range and differential and integral energy deposition enhancement for 100 keV to 2 MeV electron beams in external fields UD to lo-l6 V cm2 electric field to number density (E/N) ratio, for _& = 6 gas mixtures obtained by Monte Carlo calculations of transport of fast electrons in thick absorbers modified to include the effects of an external electrical field applied across the scatterer Detailed results are given in the form of graphs directly usable by the designer C M Bowden et al, J Vat Sci Technol, 10 (6), 1973, lOO@-1004. 33 1536. An automated electron-beam mask generator. (USA) An over-all system approach has been undertaken to make electronbeam microfabrication practical in a production environment at throughput rates which make It economlcally attractive to semiconductor manufacturers. An electron-beam system designed for fabrication of IC masks at final size in one step is described Novel features include an ultrahigh-speed 16-bit dlgital deflection system, high-vacuum compatible x-y table and a field-emission source. System features described are single operator performance, multiple methods to input mask designs, high-speed deflection system, and ‘intelligent’ beam logic interface and CAD system The system IS capable of producing 1 0-r lines with *to 2-p precision over a 0.25 Y 0.25~in. scan field with coverage of 3 :’ 3-in masks using step and repeat techniques The system also includes an automated load-lock, cryopumped vacuum system and a high-speed 1B-bit minicomputer System parameters such as throughout time, writing speed, and factors affecting these parameters will be discussed E B Friedmann et al, J Vat Sci Technol, 10 (6), 1973, 102&1024. 33 1537. Diluent cooling of a vacuum-ultraviolet high-pressure xenon laser. (USA) Experimental results are presented on the effect of diluent cooling of a 1721-A high-pressure xenon laser produced with a pulsed beam of high-energy electrons Both helium and argon were used as dduents in order to limit the rise in the gas temperature that occurs when the electron beam is stopped in the gas. In the Xe-He mixtures the chemistry was not significantly altered by the presence of He; but in the Xe-Ar mixtures, argon was very Important in the absorption and transfer of internal electronic energy. The results demonstrate that both dduents improve the operational characteristics of the laser. Only helium is found to improve the efficiency of conversion of electron-beam energy into stored laser energy. A W Johnson and J B Gerardo, J Appl Phys, 45 (2), 1974, 867-872. 33 1538. Plasma production from solid targets by nanosecond prep&es. (USA) A model of the laser-plasma-sohd system IS developed to study the dynamics of the laser prepulse interaction with mitially solid slabs. Experiments are conducted using aluminium wires and fast-rise ruby lasers and the results are used to verify the theoretlcal model. The results of numerical experlmentsare used toinvestigate the dependence of plasma formatlon on the prepulse parameters and to find those parameters which lead to efficient coupling of a subsequent giant heating pulse with the target material. E B Goldman et al, J Appl Phys, 45 (3), 1974, 1158-I 170. 426
33 1539. Measurements of the energy distribution of hackscattered kilovolt electrons with a spherical retarding-field energy analyser. (UK) A spherical retardmg-field electron energy analyser has been constructed to investigate the backscattermg and transmlsslon of electrons in the energy range 10-30 keV. It consists of full-spherical meshes with collector, and attams a resolution of about 2 ‘A By using this apparatus, the energy distribution of electrons backscattered from C, Al, Cu, Au and Cu-Au alloy specimens is obtamed Results are compared with those obtamed from Monte Carlo calculations (Japan) T Matsukawa et al, J f/zys D: ApplPiz.w, 7 (5), 1970, 695-702 33 1540. A time resolved spectrometer for high intensity relativistic electron beams. (USA) A spectrometer system deslgned to measure the time-dependent kmetlc energy of electrons from high current pulsed relativistic beam accelerators is described. The spectrometer, consistmg of a threeelement vacuum Compton diode, IS simple, rugged, and self-drivmg. Calibration data are presented covering the energy range of 150 keV to 16 MeV. Applications and limitations of the spectrometer are discussed. J V Walker and J Stevens, Rerl Srrent fnstrum. 45 (2), 1974, 163-170. 33.30 1541. A thin film thermopile for neutral particle heam measurements. (UK) A simple design 1s described for a sensitive thm film thermopde (12 V W- ‘) which IS smtable for measurements on low energy neutral beams m the range 300 eV-3keV. The device has been used as a secondary standard to calibrate fast response (7 _ 10mh s) neutral particle energy analysers which incorporate gas strlppmg cells. L E Sharp et al, Rep SC-IInstrum, 45 (3), 1974, 378-381 33 1542. Soft X-ray appearance potential spectroscopy. (USA) The total soft X-ray emission of an electron-bombarded surface exhibits abrupt changes at the threshold potentials for the excitation of core levels of surface atoms. These features represent the excitation probabilities of core states superimposed on a-smoothly increasing bremsstrahlung background The threshold ootentials can be sensetlvely detected-by d&erentiating the current from an X-ray photocathode with respect to sample potential. This technique represents the highest resolution core-level spectroscopy available We discuss the principles underlying the design and operation of soft X-ray appearance potential spectrometers and review their application to the study of surface composition, electron binding energies, chemical shifts, and band structure. R L Park and J E Houston, .I Vuc Scr Technol, 11 (1). 1974, l-18. 33 1543. Miscellaneous topics in Auger electron spectroscopy. (USA) Some of the history of the development of Auger electron spectroscopy and the author’s part in it are outlined. Unpublished work on scanning Auger microscopy IS briefly discussed. L A Harris, J Vat Sci Technol, 11 (I ), 1974, 23-28). 33 1544. The application of electron spectroscopy to surface studies. (USA) The apphcatlon of three branches of electron spectroscopy to surface studies, with particular emphasis on submonolayer chemisorption systems, is reviewed The three branches are X-ray photoelectron spectroscopy (XPS), vacuum uv photoelectron spectroscopy (UPS), and Auger electron spectroscopy (AES). Each technique is consrdered from the standpomts of (I) the depth of material probes, (il) signal strength, (Iii) quantitative aspects, (IV) chemical information obtalnable, and (v) Induced surface effects. Since UPS does not provide an atomic Identdicatlon, It IS best used m conjunction with erther of the other two techmques. In general, XPS will provide more chemical information, more quantitatively, than AES, though analysis times are slower However, since the three techniques have advantages and disadvantage? which may depend on the system studied and the obJect of the study, a combmation of the three IS usually preferable and can be experimentally achieved using only one electron energy analyzer (UK) C R Brundle, J Vuc Sri Tech&, 11(l), 1974,Z 12-224.
1535-l 544
aberration coefficient of 0.5 nm. A lanthanum hexaborlde cathode is 10’ A/cm* sr at employed with a maximum brightness of 1.5 75 kV. The cathode operates satisfactonly at a pressure of 10m6 mm Hg The theoretical minimum beam size for the Instrument 1s 5 A. Transmission scanning electron micrographs with a beam current of 1 /( lo-‘Z-3 x lo-‘2 A Indicates that close to this value IS obtained m practice. A N Broers, J vu’acSci Technol, 10 (6), 1973, 979-982. 33 1535. Range and energy deposition enhancement of a fast electron heam by external electric fields. (USA) The electrode configuratIon m electron-beam prelonized electrlcal discharge pumped molecular gas lasers can be arranged such that the drift field of the pump accelerates the fast electrons which are concurrently scattered. In deslgmng lasers with output pulses beyond the kJ energy level, one uses the drift field to extend the range and to enhance the energy deposition of the fast electron beam. Although scattering and energy loss of electrons penetrating mto matter without an external field is well known, electrical fields of the order of kV cm-’ at atmosphere pressures substantially affect both the range and the energy deposition of the primaries. We report numerlcal results in range and differential and integral energy deposition enhancement for 100 keV to 2 MeV electron beams in external fields UD to lo-l6 V cm2 electric field to number density (E/N) ratio, for _& = 6 gas mixtures obtained by Monte Carlo calculations of transport of fast electrons in thick absorbers modified to include the effects of an external electrical field applied across the scatterer Detailed results are given in the form of graphs directly usable by the designer C M Bowden et al, J Vat Sci Technol, 10 (6), 1973, lOO@-1004. 33 1536. An automated electron-beam mask generator. (USA) An over-all system approach has been undertaken to make electronbeam microfabrication practical in a production environment at throughput rates which make It economlcally attractive to semiconductor manufacturers. An electron-beam system designed for fabrication of IC masks at final size in one step is described Novel features include an ultrahigh-speed 16-bit dlgital deflection system, high-vacuum compatible x-y table and a field-emission source. System features described are single operator performance, multiple methods to input mask designs, high-speed deflection system, and ‘intelligent’ beam logic interface and CAD system The system IS capable of producing 1 0-r lines with *to 2-p precision over a 0.25 Y 0.25~in. scan field with coverage of 3 :’ 3-in masks using step and repeat techniques The system also includes an automated load-lock, cryopumped vacuum system and a high-speed 1B-bit minicomputer System parameters such as throughout time, writing speed, and factors affecting these parameters will be discussed E B Friedmann et al, J Vat Sci Technol, 10 (6), 1973, 102&1024. 33 1537. Diluent cooling of a vacuum-ultraviolet high-pressure xenon laser. (USA) Experimental results are presented on the effect of diluent cooling of a 1721-A high-pressure xenon laser produced with a pulsed beam of high-energy electrons Both helium and argon were used as dduents in order to limit the rise in the gas temperature that occurs when the electron beam is stopped in the gas. In the Xe-He mixtures the chemistry was not significantly altered by the presence of He; but in the Xe-Ar mixtures, argon was very Important in the absorption and transfer of internal electronic energy. The results demonstrate that both dduents improve the operational characteristics of the laser. Only helium is found to improve the efficiency of conversion of electron-beam energy into stored laser energy. A W Johnson and J B Gerardo, J Appl Phys, 45 (2), 1974, 867-872. 33 1538. Plasma production from solid targets by nanosecond prep&es. (USA) A model of the laser-plasma-sohd system IS developed to study the dynamics of the laser prepulse interaction with mitially solid slabs. Experiments are conducted using aluminium wires and fast-rise ruby lasers and the results are used to verify the theoretlcal model. The results of numerical experlmentsare used toinvestigate the dependence of plasma formatlon on the prepulse parameters and to find those parameters which lead to efficient coupling of a subsequent giant heating pulse with the target material. E B Goldman et al, J Appl Phys, 45 (3), 1974, 1158-I 170. 426
33 1539. Measurements of the energy distribution of hackscattered kilovolt electrons with a spherical retarding-field energy analyser. (UK) A spherical retardmg-field electron energy analyser has been constructed to investigate the backscattermg and transmlsslon of electrons in the energy range 10-30 keV. It consists of full-spherical meshes with collector, and attams a resolution of about 2 ‘A By using this apparatus, the energy distribution of electrons backscattered from C, Al, Cu, Au and Cu-Au alloy specimens is obtamed Results are compared with those obtamed from Monte Carlo calculations (Japan) T Matsukawa et al, J f/zys D: ApplPiz.w, 7 (5), 1970, 695-702 33 1540. A time resolved spectrometer for high intensity relativistic electron beams. (USA) A spectrometer system deslgned to measure the time-dependent kmetlc energy of electrons from high current pulsed relativistic beam accelerators is described. The spectrometer, consistmg of a threeelement vacuum Compton diode, IS simple, rugged, and self-drivmg. Calibration data are presented covering the energy range of 150 keV to 16 MeV. Applications and limitations of the spectrometer are discussed. J V Walker and J Stevens, Rerl Srrent fnstrum. 45 (2), 1974, 163-170. 33.30 1541. A thin film thermopile for neutral particle heam measurements. (UK) A simple design 1s described for a sensitive thm film thermopde (12 V W- ‘) which IS smtable for measurements on low energy neutral beams m the range 300 eV-3keV. The device has been used as a secondary standard to calibrate fast response (7 _ 10mh s) neutral particle energy analysers which incorporate gas strlppmg cells. L E Sharp et al, Rep SC-IInstrum, 45 (3), 1974, 378-381 33 1542. Soft X-ray appearance potential spectroscopy. (USA) The total soft X-ray emission of an electron-bombarded surface exhibits abrupt changes at the threshold potentials for the excitation of core levels of surface atoms. These features represent the excitation probabilities of core states superimposed on a-smoothly increasing bremsstrahlung background The threshold ootentials can be sensetlvely detected-by d&erentiating the current from an X-ray photocathode with respect to sample potential. This technique represents the highest resolution core-level spectroscopy available We discuss the principles underlying the design and operation of soft X-ray appearance potential spectrometers and review their application to the study of surface composition, electron binding energies, chemical shifts, and band structure. R L Park and J E Houston, .I Vuc Scr Technol, 11 (1). 1974, l-18. 33 1543. Miscellaneous topics in Auger electron spectroscopy. (USA) Some of the history of the development of Auger electron spectroscopy and the author’s part in it are outlined. Unpublished work on scanning Auger microscopy IS briefly discussed. L A Harris, J Vat Sci Technol, 11 (I ), 1974, 23-28). 33 1544. The application of electron spectroscopy to surface studies. (USA) The apphcatlon of three branches of electron spectroscopy to surface studies, with particular emphasis on submonolayer chemisorption systems, is reviewed The three branches are X-ray photoelectron spectroscopy (XPS), vacuum uv photoelectron spectroscopy (UPS), and Auger electron spectroscopy (AES). Each technique is consrdered from the standpomts of (I) the depth of material probes, (il) signal strength, (Iii) quantitative aspects, (IV) chemical information obtalnable, and (v) Induced surface effects. Since UPS does not provide an atomic Identdicatlon, It IS best used m conjunction with erther of the other two techmques. In general, XPS will provide more chemical information, more quantitatively, than AES, though analysis times are slower However, since the three techniques have advantages and disadvantage? which may depend on the system studied and the obJect of the study, a combmation of the three IS usually preferable and can be experimentally achieved using only one electron energy analyzer (UK) C R Brundle, J Vuc Sri Tech&, 11(l), 1974,Z 12-224.