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Reactive ion beam etching of tantalum silicide for VLSI applications
at grain boundaries and microdefects. The conditions are detailed under which the lifetime increases with injection level.
Newer resists based on "'onium" salt chemistry and having chemical amplification may find u ~ at high speed Xray resists in the future.
Novolac resins used in positive resist systems. T.R. PAMPALONE SoildSt. Technol. 115 (June 1984) Positive resists are used to fabricate the majority of electronic devices with geometries below 5 #m. Despite this wide-spread usage, relatively little is known about the major component of most positive resist films, which is the novolac resin. This article discusses the synthetic procedures for manufacturing novolac resins, the use of novolacs in making resists, and the effect of the novolac components on the lithographic and general properties of the resist.
A novel electroless technique for copper metallization of alumina substrates. L.G. B H A T G A D D E and S. M A H A P A T R A SolidSt. TechnoL 181 (December 1983) A simple electroless technique employing a cupric acetate-hydrazine hydrate bath for copper coating of alumina substrates is described. The technique does not require sensitization and activation pretreatments of substrates. Consequently, it has the advantages of a smaller number of raw materials and processing steps as well as lower cost compared to the traditional technique.
The density of platinum and palladium ponders for thick film pastes. ROLAND P. ANJARD, Sr. Microelectron. J. 15, 30 (1984) In the manufacture of pastes for the mieroelectronics industry, the properties of all the ingredients are carefully tested for many varied properties. The properties of the powdered metals are very critical and one of these characteristics of special concern is the apparent density. Pastes are used for individual components, such as multilayer capacitors as internal electrode, or as end termination. Platinum and palladium powders are used extensively in these complex pastes, usually with other precious metals such as silver or gold. Approaches to determine the the apparent density include the Scott density, the tap density and pycnometer density, few paste manufacturing firms use this instrument. It is interesting to note that virtually all of the published articles in the past years have dealt with pycnometer and virtually mone with the Scott or tap density systems. However, a detailed computer search found no technical publication by any of these or other techniques. X-ray resist trend. GARY N. TAYLOR Solid St. Technol. 124 (June 1984) Recent trends in materials research for X-ray lithography are reviewed. The types of resists used in the future will depend primarily on source availability. For the more exotic, but as yet unproven, plasma and synchroton sources, less sensitive positive resists have sensitivities in the 50 and ~ 100mJ cm 2 ranges, respectively, appear optimum. For conventional and plasma sources, multilevel resist processing will be required whereas single level processing can be used with the very intense sunchrotron sources. For conventional target systems, solution-developed negative resists with somewhat inferior sensitivity are useful at dimensions slightly < 1 #m. For finer resolution and improvbed speed, plasmadeveloped resists' appear very attractive. High throughput, high resolutiog step-and-repeat X-ray lithography using multilevel processing may be possible with plasma-developed resists at submicron dimensions.
54
G rain-boundary scattering and surface plasmon attenuation in noble metal films. J.R. SAMBLES Solid St. Commtu~. 49, (4), 343 (1984) It is shown how grain-boundary and not surface scattering may explain the large range in values found for the attenuation coefficient of surface plasmons propagating on thin noble metal films. Reactive ion beam etching of tantalum silicide for VLSI applications. A. BAUDRANT, A. PASSERAT and D. BOLLINGER SolidSt. Technol. 183 (September 1983) Tantalum silicide technology can now be applied to overcome difficulties arising with polysilicon and aluminium in small geometry, multilevel interconnect, VLSI applications. Clean, anisotropically etched patterns in TaSi2 and TaSi2 polysilicon are obtained through reactive ion beam etching (R1BE). For these materials, reactive ion etch and plasma etch processes have difficulty in avoiding both residue and undercut. Reactive ion beam etching is shown to etch (equally well) TaSi2 and doped polysilicon deposited by different means. This process is then suitable for the various MOS applications of TaSz replacement of polysilicon gate electrodes and interconnects and replacement of aluminium as a second level "metal" interconnect. High performance thick film gold conductors. R.R. GE'iq'Y, B.E. TAYLOR and C.R.S. NEEDLES Solid St. TechnoL i 63 (October 1983) A new generation of high performance thick-film gold conductor compositions designed to meet the requirments of new and demanding applications is described. The compositions incorporate new gold powder and vehicle technologies to provide the processing latitude necessary for improved circuit yields. Monodisperse spherical gold powder imparts a high degree of uniformity to these compositions and is primarily responsible for exceptional functional properties, in particular, smooth fired surfaces and good backlit densities. The vehicle system gives rise to excellent printing characteristics, even after long print runs. Both the powder
Newer resists based on "'onium" salt chemistry and having chemical amplification may find u ~ at high speed Xray resists in the future.
Novolac resins used in positive resist systems. T.R. PAMPALONE SoildSt. Technol. 115 (June 1984) Positive resists are used to fabricate the majority of electronic devices with geometries below 5 #m. Despite this wide-spread usage, relatively little is known about the major component of most positive resist films, which is the novolac resin. This article discusses the synthetic procedures for manufacturing novolac resins, the use of novolacs in making resists, and the effect of the novolac components on the lithographic and general properties of the resist.
A novel electroless technique for copper metallization of alumina substrates. L.G. B H A T G A D D E and S. M A H A P A T R A SolidSt. TechnoL 181 (December 1983) A simple electroless technique employing a cupric acetate-hydrazine hydrate bath for copper coating of alumina substrates is described. The technique does not require sensitization and activation pretreatments of substrates. Consequently, it has the advantages of a smaller number of raw materials and processing steps as well as lower cost compared to the traditional technique.
The density of platinum and palladium ponders for thick film pastes. ROLAND P. ANJARD, Sr. Microelectron. J. 15, 30 (1984) In the manufacture of pastes for the mieroelectronics industry, the properties of all the ingredients are carefully tested for many varied properties. The properties of the powdered metals are very critical and one of these characteristics of special concern is the apparent density. Pastes are used for individual components, such as multilayer capacitors as internal electrode, or as end termination. Platinum and palladium powders are used extensively in these complex pastes, usually with other precious metals such as silver or gold. Approaches to determine the the apparent density include the Scott density, the tap density and pycnometer density, few paste manufacturing firms use this instrument. It is interesting to note that virtually all of the published articles in the past years have dealt with pycnometer and virtually mone with the Scott or tap density systems. However, a detailed computer search found no technical publication by any of these or other techniques. X-ray resist trend. GARY N. TAYLOR Solid St. Technol. 124 (June 1984) Recent trends in materials research for X-ray lithography are reviewed. The types of resists used in the future will depend primarily on source availability. For the more exotic, but as yet unproven, plasma and synchroton sources, less sensitive positive resists have sensitivities in the 50 and ~ 100mJ cm 2 ranges, respectively, appear optimum. For conventional and plasma sources, multilevel resist processing will be required whereas single level processing can be used with the very intense sunchrotron sources. For conventional target systems, solution-developed negative resists with somewhat inferior sensitivity are useful at dimensions slightly < 1 #m. For finer resolution and improvbed speed, plasmadeveloped resists' appear very attractive. High throughput, high resolutiog step-and-repeat X-ray lithography using multilevel processing may be possible with plasma-developed resists at submicron dimensions.
54
G rain-boundary scattering and surface plasmon attenuation in noble metal films. J.R. SAMBLES Solid St. Commtu~. 49, (4), 343 (1984) It is shown how grain-boundary and not surface scattering may explain the large range in values found for the attenuation coefficient of surface plasmons propagating on thin noble metal films. Reactive ion beam etching of tantalum silicide for VLSI applications. A. BAUDRANT, A. PASSERAT and D. BOLLINGER SolidSt. Technol. 183 (September 1983) Tantalum silicide technology can now be applied to overcome difficulties arising with polysilicon and aluminium in small geometry, multilevel interconnect, VLSI applications. Clean, anisotropically etched patterns in TaSi2 and TaSi2 polysilicon are obtained through reactive ion beam etching (R1BE). For these materials, reactive ion etch and plasma etch processes have difficulty in avoiding both residue and undercut. Reactive ion beam etching is shown to etch (equally well) TaSi2 and doped polysilicon deposited by different means. This process is then suitable for the various MOS applications of TaSz replacement of polysilicon gate electrodes and interconnects and replacement of aluminium as a second level "metal" interconnect. High performance thick film gold conductors. R.R. GE'iq'Y, B.E. TAYLOR and C.R.S. NEEDLES Solid St. TechnoL i 63 (October 1983) A new generation of high performance thick-film gold conductor compositions designed to meet the requirments of new and demanding applications is described. The compositions incorporate new gold powder and vehicle technologies to provide the processing latitude necessary for improved circuit yields. Monodisperse spherical gold powder imparts a high degree of uniformity to these compositions and is primarily responsible for exceptional functional properties, in particular, smooth fired surfaces and good backlit densities. The vehicle system gives rise to excellent printing characteristics, even after long print runs. Both the powder