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The electrocomposer, a high speed integrated circuit mask tracer using an electron beam
268
World Abstracts on Microelectronics and Reliability
can be extended to deeper junction epitaxial buried channel devices,
alignment of the electron deflection axes to witfiin 0.002 rad of the device axes.
Edge emissions of ion-implanted CdS. YASUHIRO SHIRAKI, TOSHIr,AZU SHIMADAand KIICHI F. KOMATSUBARA.J. Phys. Chem. Solids 38, 937 (1977). Edge emissions of CdS crystals implanted wihh Li +, N +, Ne + and P+ are studied. Li and P are found to form Receptors and give rise to I~ lines in the blue a n d donor-acceptor pair recombination emissions in the green. N gives rise to two kinds of I2 lines (excitons b o u n d to neutral donors) and donor-acceptor pair recombination emissions. An acceptor due to a defect is found in N ÷ and Ne ÷ implanted CdS. The temperature range of thermal treatment where impurity centers are formed is also investigated. The relationship a m o n g impurity centers produced by N ÷ implantation is, moreover, discussed based upon the results obtained here and previous works.
Aspects of electron resist exposure. D. WEaB and C. J. HARDY. Vacuum 27, (5/6) 413. This paper describes an
The effect of argon implantation on the conductivity of boron implanted silicon. I. R. SANDERS and B. D WILLIAMS. Solid-St. Electron. 20, 703 (1977). Silicon wafers have been implanted with boron (3 × 1014 or 1 × 1015 ions cm -2) and with argon (up to 1 × 1015 i o n s c m - zt. The energies were chosen to approximately superimpose the two impurity distributions. After the boron and argon implantations the sheet resistance of each water was measured following annealing in nitrogen at temperatures in the range 400-1050°C. The highest dose argon implantation produced an increase in sheet resistance which persisted throughout the entire temperature range. Lower argon doses produced a reduction in sheet resistance for anneal temperatures between 550 and 800°C. The magnitude of the reduction is a function of the boron and argon doses and of the anneal temperatures. The greatest reduction. observed after a 600°C anneal, was by a factor of 5.8. Above 800°C the low dose argon did not affect the sheet resistance. The observed reduction in sheet resistance is expected to lead to an improvement in metal to p-type silicon contacts. A particular application is in the contacts to resistors in fast bipolar logic circuits. As high electrical activity can be obtained at moderate annealing temperatures with combined boron and argon implantations, these implantations can be carried out at a late stage in an integrated circuit process schedule without the danger of additional movement of existing junctions.
Detection and processing of secondary electron signals for pattern re-registration in scanning electron beam exposure. S. O. ALIO and C. J. HARDY. Vacuum 27, (5/6) 419. The fabrication of electronic devices on any wafer requires m a n y etching and diffusion processes. Each of these steps necessitates the use of a resist to control the etching process. For steps subsequent to the first, it is essential to achieve accurate alignment between areas already defined on the slice and the related areas to be formed in the next step. The present trend in the technology of semiconductor devices is both to reduce the overall size of the completed circuit and also to produce circuits containing larger n u m b e r s of components. Both of these tendencies require smaller component sizes. This has led to the search for improved photolithographic techniques and the development of X-ray and electron beam lithographies. With reduced c o m p o n e n t size, not only the dimension of the pattern but also the position need to be controlled accurately. This paper describes a system which has been developed for the detection of secondary electrons emitted from the substrate surface. The secondary electron signal is processed to control the positioning of patterns to within +0.25 #m of the desired site. and to adjust the rotational
attempt to devise a theoretical model of electron beam exposure of sensitive resists• The problem is divided into two parts. First, the energy dissipation in the resist layer caused by electron scattering in the target is calculated• This done for an elliptical beam of gaussian current density distribution. The results for a single spot are combined by a computer program to produce exposure maps of the general patterns exposed by the departmental electron beam machine. A comparison between the theory and some practical results is presented. Second, the solubility of resist in developer is calculated as a function of absorbed radiation dose. This is done not only for linear polymers but also for thermally crosslinked positive resists. In the first case polymer fractionation theory is applied to the development process. In the second, some practical results are presented: these are consistent with the theory.
The electrocomposer, a high speed integrated circuit mask tracer using an electron beam. J. TROTEL, A. GERARD and S. OESPERGUES-VOLMIER. Rev. Technique Thomson-CSF 9, (2) 245 (June 1977). (In French only.) The Electrocomposer was developed for tracing integrated circuit masks on a 10:1 scale in an industrial environment. A mask tracing is obtained by compounding a continuous motion of the table supporting the sample with motion of the electron beam at right angles to the table motion. This c o m p o u n d i n g process, which could be likened to a television scanning with the image scanning done mechanically, provides a tracing of a strip-shaped portion of the pattern, whose shorter 1.25 m m sides represent the extent of the electronic scan and whose longer sides of 1.25 m m m a x i m u m length represent the extent of the mechanical scan. The complete mask tracing is obtained by juxtaposing these strips. The table's movements are measured by two interferometers. The tracing can be defined as being a combination of polygons whose sides can be parallel to the X and Y axes and to the latter's bisectors. The data required by the machine are the coordinates of the apices of the polygons and an indicator to define the shape of each apex. The electron optic system consists of a l a n t h a n u m boride electron gun operating at 20 kV and a device enabling a 2.5 x 2.5 micron square beam to be projected. Leading particulars of the system are as follows: - - m a x i m u m dimensions of mask support; 153 × 153 x 6 m m ; - - m a x i m u m area exposed: 125 x 125 m m ; -minim u m pattern increments: 2.5/~m; - - m i n i m u m width of tracing lines: 2.5/~m; --typical sample: a chromium plate covered with AZ 1,350 resists; - - m a x i m u m time for tracing a 7 5 r a m x 7 5 m m mask: 17rain.
Effects of dislocations in silicon transistors with implanted bases, P. ASHBURN, C. BULL, K. H. NICHOLAS and G. R. BROOKER. Solid-St. Electron• 20. 731 (1977). Silicon bipolar transistors have been made by substituting a shallow boron implantation for the standard base deposition used in the manufacture of integrated circuits. This was followed by a high-temperature oxidation drive-in, and the transistor structure completed with a standard phosphorus deposition and drive-in. The implantations were performed through oxides with thicknesses in the range 0.08~).17 ,urn. For the 0.17pm transistors, the electrical characteristics were comparable with standard diffused transistors, while for the 0.08 ~m transistors low gains and high emitter/base
World Abstracts on Microelectronics and Reliability
can be extended to deeper junction epitaxial buried channel devices,
alignment of the electron deflection axes to witfiin 0.002 rad of the device axes.
Edge emissions of ion-implanted CdS. YASUHIRO SHIRAKI, TOSHIr,AZU SHIMADAand KIICHI F. KOMATSUBARA.J. Phys. Chem. Solids 38, 937 (1977). Edge emissions of CdS crystals implanted wihh Li +, N +, Ne + and P+ are studied. Li and P are found to form Receptors and give rise to I~ lines in the blue a n d donor-acceptor pair recombination emissions in the green. N gives rise to two kinds of I2 lines (excitons b o u n d to neutral donors) and donor-acceptor pair recombination emissions. An acceptor due to a defect is found in N ÷ and Ne ÷ implanted CdS. The temperature range of thermal treatment where impurity centers are formed is also investigated. The relationship a m o n g impurity centers produced by N ÷ implantation is, moreover, discussed based upon the results obtained here and previous works.
Aspects of electron resist exposure. D. WEaB and C. J. HARDY. Vacuum 27, (5/6) 413. This paper describes an
The effect of argon implantation on the conductivity of boron implanted silicon. I. R. SANDERS and B. D WILLIAMS. Solid-St. Electron. 20, 703 (1977). Silicon wafers have been implanted with boron (3 × 1014 or 1 × 1015 ions cm -2) and with argon (up to 1 × 1015 i o n s c m - zt. The energies were chosen to approximately superimpose the two impurity distributions. After the boron and argon implantations the sheet resistance of each water was measured following annealing in nitrogen at temperatures in the range 400-1050°C. The highest dose argon implantation produced an increase in sheet resistance which persisted throughout the entire temperature range. Lower argon doses produced a reduction in sheet resistance for anneal temperatures between 550 and 800°C. The magnitude of the reduction is a function of the boron and argon doses and of the anneal temperatures. The greatest reduction. observed after a 600°C anneal, was by a factor of 5.8. Above 800°C the low dose argon did not affect the sheet resistance. The observed reduction in sheet resistance is expected to lead to an improvement in metal to p-type silicon contacts. A particular application is in the contacts to resistors in fast bipolar logic circuits. As high electrical activity can be obtained at moderate annealing temperatures with combined boron and argon implantations, these implantations can be carried out at a late stage in an integrated circuit process schedule without the danger of additional movement of existing junctions.
Detection and processing of secondary electron signals for pattern re-registration in scanning electron beam exposure. S. O. ALIO and C. J. HARDY. Vacuum 27, (5/6) 419. The fabrication of electronic devices on any wafer requires m a n y etching and diffusion processes. Each of these steps necessitates the use of a resist to control the etching process. For steps subsequent to the first, it is essential to achieve accurate alignment between areas already defined on the slice and the related areas to be formed in the next step. The present trend in the technology of semiconductor devices is both to reduce the overall size of the completed circuit and also to produce circuits containing larger n u m b e r s of components. Both of these tendencies require smaller component sizes. This has led to the search for improved photolithographic techniques and the development of X-ray and electron beam lithographies. With reduced c o m p o n e n t size, not only the dimension of the pattern but also the position need to be controlled accurately. This paper describes a system which has been developed for the detection of secondary electrons emitted from the substrate surface. The secondary electron signal is processed to control the positioning of patterns to within +0.25 #m of the desired site. and to adjust the rotational
attempt to devise a theoretical model of electron beam exposure of sensitive resists• The problem is divided into two parts. First, the energy dissipation in the resist layer caused by electron scattering in the target is calculated• This done for an elliptical beam of gaussian current density distribution. The results for a single spot are combined by a computer program to produce exposure maps of the general patterns exposed by the departmental electron beam machine. A comparison between the theory and some practical results is presented. Second, the solubility of resist in developer is calculated as a function of absorbed radiation dose. This is done not only for linear polymers but also for thermally crosslinked positive resists. In the first case polymer fractionation theory is applied to the development process. In the second, some practical results are presented: these are consistent with the theory.
The electrocomposer, a high speed integrated circuit mask tracer using an electron beam. J. TROTEL, A. GERARD and S. OESPERGUES-VOLMIER. Rev. Technique Thomson-CSF 9, (2) 245 (June 1977). (In French only.) The Electrocomposer was developed for tracing integrated circuit masks on a 10:1 scale in an industrial environment. A mask tracing is obtained by compounding a continuous motion of the table supporting the sample with motion of the electron beam at right angles to the table motion. This c o m p o u n d i n g process, which could be likened to a television scanning with the image scanning done mechanically, provides a tracing of a strip-shaped portion of the pattern, whose shorter 1.25 m m sides represent the extent of the electronic scan and whose longer sides of 1.25 m m m a x i m u m length represent the extent of the mechanical scan. The complete mask tracing is obtained by juxtaposing these strips. The table's movements are measured by two interferometers. The tracing can be defined as being a combination of polygons whose sides can be parallel to the X and Y axes and to the latter's bisectors. The data required by the machine are the coordinates of the apices of the polygons and an indicator to define the shape of each apex. The electron optic system consists of a l a n t h a n u m boride electron gun operating at 20 kV and a device enabling a 2.5 x 2.5 micron square beam to be projected. Leading particulars of the system are as follows: - - m a x i m u m dimensions of mask support; 153 × 153 x 6 m m ; - - m a x i m u m area exposed: 125 x 125 m m ; -minim u m pattern increments: 2.5/~m; - - m i n i m u m width of tracing lines: 2.5/~m; --typical sample: a chromium plate covered with AZ 1,350 resists; - - m a x i m u m time for tracing a 7 5 r a m x 7 5 m m mask: 17rain.
Effects of dislocations in silicon transistors with implanted bases, P. ASHBURN, C. BULL, K. H. NICHOLAS and G. R. BROOKER. Solid-St. Electron• 20. 731 (1977). Silicon bipolar transistors have been made by substituting a shallow boron implantation for the standard base deposition used in the manufacture of integrated circuits. This was followed by a high-temperature oxidation drive-in, and the transistor structure completed with a standard phosphorus deposition and drive-in. The implantations were performed through oxides with thicknesses in the range 0.08~).17 ,urn. For the 0.17pm transistors, the electrical characteristics were comparable with standard diffused transistors, while for the 0.08 ~m transistors low gains and high emitter/base