Tim Weidman - Academia.edu (original) (raw)
Papers by Tim Weidman
Thesis (Ph. D. in Chemistry)--University of California, Berkeley, Dec. 1986. Includes bibliograph... more Thesis (Ph. D. in Chemistry)--University of California, Berkeley, Dec. 1986. Includes bibliographical references (leaves 174-184).
Physical review. B, Condensed matter, Jan 15, 1993
ABSTRACT The nature of ultrafast energy dissipation in poly(n-hexylsilyne), a prototypical sigma-... more ABSTRACT The nature of ultrafast energy dissipation in poly(n-hexylsilyne), a prototypical sigma-delocalized alkylsilicon-network polymer is reported. This disordered, silicon-backbone material exhibits strong near-UV to visible band-edge absorption and a high quantum yield of visible emission. The time evolution of the emission band is studied over four decades of time using time-resolved luminescence as a probe. The data indicate that while there is an ``intrinsic'' Stokes shift after photoexcitation due to kinetic-energy relaxation, (
ABSTRACT We review the first transient photophysical data on the “ polysilynes ”, a new class of ... more ABSTRACT We review the first transient photophysical data on the “ polysilynes ”, a new class of extensively crosslinked silicon skeletal polymeric materials. Using steady-state and picosecond spectroscopic techniques we develop a consistent structural picture which illustrates the evolution of the polymer spectral characteristics. The data suggests that in polysilynes photoexcitation results in the generation of localized electron-hole pairs. The recombination dynamics of these carriers may be successfully predicted by a recombination model similar to those used to explain luminescence in amorphous semiconductors.
ECS Transactions, 2007
ABSTRACT This work presents the impact of Co(III) species in electroless cobalt solutions on plat... more ABSTRACT This work presents the impact of Co(III) species in electroless cobalt solutions on plating bath performance such as initiation and growth rate, deposit selectivity, coverage and uniformity. The results indicate that excessive Co(III) content can delay initiation significantly and cause copper erosion during induction period, leading to a decrease of deposit uniformity, an increased surface roughness, and in some cases loss of selectivity. Methods for inhibition of Co(III) formation are also presented.
Synthetic Metals, 1992
ABSTRACT The nature of ultrafast energy dissipation in poly(n-hexylsilyne), a prototypical σ-delo... more ABSTRACT The nature of ultrafast energy dissipation in poly(n-hexylsilyne), a prototypical σ-delocalized alkysilicon network polymer, is explored. This disordered silicon backbone material exhibits strong near-UV to visible band-edge absorption and a high quantum yield of visible emission. The time evolution of the emission band is studied over four decades of time using time-resolved luminescence as a probe. The data indicate that while there is an ‘intrinsic’ Stokes shift after photoexcitation due to kinetic energy relaxation (<10ps), thermalization within a dense band of vibronic states via intramolecular phonon-assisted hopping on a nanosecond timescale is the dominant mechanism for excited-state decay. The data can be understood in terms of theoretical predictions for energy relaxation in disordered materials.
The Journal of Physical Chemistry, 1991
... Poly( hexy imethylsily iene) Copolymers William L. Wilson* and Timothy W. Weidman AT&... more ... Poly( hexy imethylsily iene) Copolymers William L. Wilson* and Timothy W. Weidman AT&amp;amp;amp; T Bell Laboratories, Murray Hill, New Jersey 07974 (Received: November 2, 1990) ... Chem.) 1986. 27, 109. (j) Schilling, F. C.; Bovey, F. A,; Ziegler, JM Macromolecules 1986, 19,2309. ...
Journal of the American Chemical Society, 1997
Broad-band irradiation (λ max ) 350 nm) of FvRu 2 (CO) 4 (1, Fv ) η 5 :η 5 -bicyclopentadienyl) r... more Broad-band irradiation (λ max ) 350 nm) of FvRu 2 (CO) 4 (1, Fv ) η 5 :η 5 -bicyclopentadienyl) resulted in rapid isomerization to colorless (µ 2 -η 1 :η 5 -cyclopentadienyl) 2 Ru 2 (CO) 4 (2) in a novel process involving a formal dinuclear oxidative addition to a C-C bond. The product reverted to 1 upon heating in solution or in the solid state, under the latter conditions with an enthalpy change of -29.8 (1.5) kcal mol -1 . Mechanistic studies with a mixture of 1 and 1-d 8 revealed the absence of label scrambling, pointing to intramolecular pathways. The quantum yield (0.15) was unaffected by the presence of CCl 4 , and no chlorination products were observed under these conditions. Irradiation of solutions of 1 or 2 with 300 nm light provided Fv(µ 2 -η 1 :η 5 -cyclopentadienyl) 2 Ru 4 (CO) 6 (6) or, in the presence of alkynes, the adducts FvRu 2 (CO) 3 (RCCR) (8-10, R ) H, C 6 H 5 , CO 2 CH 3 ). Heating 1 and PR 3 (R ) CH 2 CH 3 , CH 3 , or OCH 3 ) yielded FvRu 2 (CO) 3 (PR 3 ) (12-14), in which a fluxional process occurs characterized by intramolecular terminal to bridging carbonyl exchange. While 12 and 13 were inert, compound 14 rapidly and reversibly afforded the P(OCH 3 ) 3 -substituted analog of 2 (15) upon irradiation with UV light. The two diastereomeric 3,3′-di-tert-butyl-substituted fulvalene analogs of 1 (19) underwent the same reaction sequence with complete retention of stereochemistry, via the diastereomeric photoproducts 20. A double regiochemical labeling experiment proceeded with retention of connectivity and stereochemistry. A concerted mechanism for the photoisomerization is consistent with the experimental observations, but a biradical pathway cannot be ruled out. Kinetic data for the isomerizations of 2, 15, 20a, and 20b to their respective metal-metal-bonded Fv precursors were determined. The entropies of activation (+7 to +21 eu) suggested a disordered transition state. A sequence involving reversible CO loss was ruled out through a crossover experiment with 2-13 CO. Kinetic and labeling experiments point to a change in mechanism when the thermal reversion of 2 to 1 was run under CO (∼1 atm). The occurrence of ligand-induced C-C coupling was indicated through studies of the reactivity of 2 with P(CH 3 ) 3 . Photoisomer 2 reacts with excess CCl 4 to give FvRu 2 (CO) 4 Cl 2 ) by yet another mechanism. As in the potoisomerization of 1, the thermal reversion of 2 may follow a concerted pathway, although biradical intermediates cannot be excluded.
Advances in Resist Technology and Processing XII, 1995
ABSTRACT Silicon dioxide is the primary dielectric fabric of silicon integrated circuits, and the... more ABSTRACT Silicon dioxide is the primary dielectric fabric of silicon integrated circuits, and the need to pattern it accounts for a large percentage of all photolithographic operations. As shrinking device dimensions place extreme demands on both lithography and etching, patterned oxide films are finding yet additional applications as intermediate `hard masks.' For example, polysilicon gate and metal layers may be etched with greater selectivity and linewidth control through a thin patterned oxide mask, rather than through a thicker photoresist layer (which is used to pattern the oxide and removed before pattern transfer). However, any advantages of such schemes must be weighed against the costs of increasing process complexity. We recently reported a new all-dry photolithographic process based on the plasma deposition and patterning of organosilicon resists. These materials, as best exemplified by plasma polymerized methylsilane (PPMS), possess amorphous Si-Si bond backbone structures and undergo efficient photo-oxidation to give glasslike siloxane network material. Patterns are developed using chlorine plasma etching to selectively remove unexposed regions, providing a negative tone image. In previous papers we have demonstrated the use of these materials in bilevel processes, using oxygen reactive ion etching to transfer patterns in thin PPMS layers through underlying organic planarizing layers. Using 248 nm deep UV exposure tools, such schemes afford sub-0.25 micrometers design rule capabilities and are well suited for difficult device topography. Here we describe the discovery and development of a fundamentally different application unique to PPMS: a new direct approach to patterned silicon dioxide.
Optical/Laser Microlithography, 1993
ABSTRACT
Advances in Resist Technology and Processing X, 1993
Advances in Resist Technology and Processing XVI, 1999
ABSTRACT Some of the major limitations of top surface imaging schemes are now well documented: cr... more ABSTRACT Some of the major limitations of top surface imaging schemes are now well documented: critical dimension (CD) control across the wafer can be a serious issue as well as line edge roughness (LER). A primary focus of our work has been to investigate the performance of the 248 nm bi-level negative tone approach of the CVD photoresist process based on the plasma polymerization of methylsilane. In this paper, CD control data within a field and across the wafer are presented. CD control is shown to be very strongly dependent on the uniformity of the development step. The best results are obtained when using straight chlorine for the plasma etch development step.
Proceedings of SPIE - The International Society for Optical Engineering
Plasma polymerization of various mono- and di-substituted organosilanes (R1R2SiH2; R1 equals alky... more Plasma polymerization of various mono- and di-substituted organosilanes (R1R2SiH2; R1 equals alkyl, aryl and R2 equals H or alkyl) provides an effective approach to a new class of organosilicon resists useful in all dry photolithographic processing. For example, parallel plate rf plasma deposition systems may be used to deposit photosensitive films from low power discharges in methylsilane (MeSiH3) gas between 200 and 500 mTorr. Characterization by FTIR, UV-Visible, and NMR spectroscopy suggests that methylsilane undergoes predominantly dehydrogenative coupling reactions, giving Si-Si bonded network materials of general composition [(MexSiHy)n], with x and y between 0.5 and 1.0. Such films exhibit intense, near-UV absorption band edges characteristic of materials with Si-Si backbones, and undergo photo-oxidative crosslinking with bleaching when irradiated with mid-deep UV light ((lambda) < 365 nm) in the presence of oxygen.
Proceedings of SPIE - The International Society for Optical Engineering
We recently introduced a new class of high performance deep-UV photoresists which are deposited v... more We recently introduced a new class of high performance deep-UV photoresists which are deposited via the gas phase plasma polymerization of methylsilane. These materials, particularly plasma polymerized methylsilane (PPMS), undergo efficient oxidation on exposure to deep-UV light in air to form a glasslike siloxane network polymer, providing patterns which may be developed and transferred into underlying substrates using all dry plasma etch processes. Here we describe a simple new procedure which affords the opposite (positive) tone image in the same resist using a wet buffered oxide etch to remove exposed regions. Lithographic performance studies (dose latitude as well as linearity data) are presented for both the negative tone and the new positive tone versions of the process.
Journal of vacuum science & technology. B, Microelectronics and nanometer structures: processing, measurement, and phenomena: an official journal of the American Vacuum Society
Vapor phase pregate oxide surface preparation was studied in a high vacuum cluster tool. SiO 2 wa... more Vapor phase pregate oxide surface preparation was studied in a high vacuum cluster tool. SiO 2 was etched with anhydrous vapor hydrogen fluoride and methanol vapor. The oxide etch rate can be well controlled by varying wafer temperature, chamber pressure, and gas flow rates. A standard error of 5% in oxide etch rate has been achieved. Particles generated are less than ten per 125 mm wafer at an oxide etch rate of 60 Å/min. Atomic force microscopy measurements reveal no added Si surface microroughness attributable to vapor hydrogen flouride (HF) etching. Trace metallic contaminants such as iron and chromium were reduced with UV/Cl 2 based processes. A combination of vapor HF etching followed by UV/Cl 2 metal removal is an effective pregate oxide surface preparation. © 1995 American Vacuum Society
Proceedings., Sixth International IEEE VLSI Multilevel Interconnection Conference, 1989
ABSTRACT Drawing on advanced packaging and interconnection schemes along with advances in VLSI te... more ABSTRACT Drawing on advanced packaging and interconnection schemes along with advances in VLSI technologies, the authors consider some examples of novel interconnection technologies. Novel polymer waveguides requiring only exposure to deep UV to fabricate a waveguide are emphasized as a potentially important material compatible with overlaying complex VLSI circuitry. Superconducting microstrip interconnections are considered. These examples suggest that conventional VLSI silicon technologies will evolve to become the support for the selective introduction of advanced interconnection technologies, yielding within the smaller system volumes of wafer-level systems the heterogeneous mixture of technologies seen in, or being introduced into, conventional, complex systems. It is pointed out that the specific examples used are microfabricated structures on substrates appropriate for achieving narrow features
Ultrasonics, 1990
ABSTRACT We have studied the effects and applications of high intensity ultrasound in the reducti... more ABSTRACT We have studied the effects and applications of high intensity ultrasound in the reductive condensation synthesis of polysilanes and polysilynes, a new class of amorphous [RSi]n alkyl silicon network polymers. Best results were obtained in the sonication of liquid Na/K alloy with R2SiCl2 and RSiCl3 monomers. Sonochemically activated reactions in Na/K alloy-hydrocarbon emulsions proceed without the normal complications associated with surface passivation, and allow more precise control of reaction rate, stoichiometry, and polymer molecular weight. In the reactions of RSiCl3 monomers, sonication also decreases the tendency towards formation of insoluble and incompletely reduced network products. These procedures allowed the isolation of the first soluble polymers with the simple composition [RSi]n, (for R = alkyl substituents of at least three carbons). All spectroscopic data indicated these materials, termed polysilynes, are constructed primarily from (sp3) hybridized alkylsilyne [RSi] fragments, irregularly assembled via Si Si single bonds into random networks.
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1998
ABSTRACT The chemical vapor deposition resist film plasma polymerized methyl silane (PPMS) can be... more ABSTRACT The chemical vapor deposition resist film plasma polymerized methyl silane (PPMS) can be used as a single layer photoresist for optical lithography at 248 and 193 nm wavelengths. Upon exposure, the PPMS undergoes efficient photo oxidation in the presence of air to yield a siloxane network (PPMSO) giving patterns that can be dry developed using a chlorine-HBr plasma. After dry development, the PPMSO can be used to transfer a pattern through organic low κ materials, or can be converted to a silicon dioxide hardmask using a conventional resist stripper, then used to transfer patterns into polysilicon. © 1998 American Vacuum Society.
Nonlinear Optical Properties of Organic Materials III, 1990
Optical Interconnections and Networks, 1990
ABSTRACT Two important issues will greatly influence the success of mapping optical interconnecti... more ABSTRACT Two important issues will greatly influence the success of mapping optical interconnections into future waferlevel distributed computing systems: (1), the scalability of active optical devices with cointegration along side ULSI components, and (2), the scalability of optical networks and components to the wafer level. If these criteria can be met, planar integrated and free-space optics can potentially provide a very high performance communication network within the multi-wafer environment. With the predominantly planar geometry and processing of waferlevel circuits, process compatible integrated planar optical interconnections are especially attractive for providing network passive connectivity. As with their electrical counterparts, spatial, as well as time division multiplexing of optical interconnections is desirable, given that layout and area constraints are not too severe. Therefore here, emphasis is shifted away from the individual behavior of traditional long distance lightwave single mode waveguides towards the collective system behaviour (i.e. density, coupling, layout, etc.) of large dense arrays of multimode optical waveguides. In this paper, initial experimental optical coupling results are presented for arrays of multimode polysilyne polymer waveguides, both for straight configurations and for arrays with radial right angle bend layouts.
Advances in Resist Technology and Processing XV, 1998
ABSTRACT Plasma polymerized methylsilane resist films (PPMS) have high sensitivity to short wavel... more ABSTRACT Plasma polymerized methylsilane resist films (PPMS) have high sensitivity to short wavelength radiation. The photoinduced oxidation of PPMS films exposed in air forms siloxane network material (called PPMSO), allowing dry development by selective etching of the unexposed regions upon treatment with chlorine based plasmas. Negative-tone patterns of oxidized methylsilane thus formed can be consolidated in a standard resist stripper to form SiO2 like hard mask patterns. In this work, PPMS films are deposited using a commercial single wafer cluster tool dedicated to dielectric deposition. After exposure at 248 or 193 nm, PPMS development is performed in a commercial high density plasma source etcher. Oxide patterns obtained from PPMS films are used for organic resist patterning (bi-layer application) and gate stack patterning (single layer application).
Thesis (Ph. D. in Chemistry)--University of California, Berkeley, Dec. 1986. Includes bibliograph... more Thesis (Ph. D. in Chemistry)--University of California, Berkeley, Dec. 1986. Includes bibliographical references (leaves 174-184).
Physical review. B, Condensed matter, Jan 15, 1993
ABSTRACT The nature of ultrafast energy dissipation in poly(n-hexylsilyne), a prototypical sigma-... more ABSTRACT The nature of ultrafast energy dissipation in poly(n-hexylsilyne), a prototypical sigma-delocalized alkylsilicon-network polymer is reported. This disordered, silicon-backbone material exhibits strong near-UV to visible band-edge absorption and a high quantum yield of visible emission. The time evolution of the emission band is studied over four decades of time using time-resolved luminescence as a probe. The data indicate that while there is an ``intrinsic'' Stokes shift after photoexcitation due to kinetic-energy relaxation, (
ABSTRACT We review the first transient photophysical data on the “ polysilynes ”, a new class of ... more ABSTRACT We review the first transient photophysical data on the “ polysilynes ”, a new class of extensively crosslinked silicon skeletal polymeric materials. Using steady-state and picosecond spectroscopic techniques we develop a consistent structural picture which illustrates the evolution of the polymer spectral characteristics. The data suggests that in polysilynes photoexcitation results in the generation of localized electron-hole pairs. The recombination dynamics of these carriers may be successfully predicted by a recombination model similar to those used to explain luminescence in amorphous semiconductors.
ECS Transactions, 2007
ABSTRACT This work presents the impact of Co(III) species in electroless cobalt solutions on plat... more ABSTRACT This work presents the impact of Co(III) species in electroless cobalt solutions on plating bath performance such as initiation and growth rate, deposit selectivity, coverage and uniformity. The results indicate that excessive Co(III) content can delay initiation significantly and cause copper erosion during induction period, leading to a decrease of deposit uniformity, an increased surface roughness, and in some cases loss of selectivity. Methods for inhibition of Co(III) formation are also presented.
Synthetic Metals, 1992
ABSTRACT The nature of ultrafast energy dissipation in poly(n-hexylsilyne), a prototypical σ-delo... more ABSTRACT The nature of ultrafast energy dissipation in poly(n-hexylsilyne), a prototypical σ-delocalized alkysilicon network polymer, is explored. This disordered silicon backbone material exhibits strong near-UV to visible band-edge absorption and a high quantum yield of visible emission. The time evolution of the emission band is studied over four decades of time using time-resolved luminescence as a probe. The data indicate that while there is an ‘intrinsic’ Stokes shift after photoexcitation due to kinetic energy relaxation (<10ps), thermalization within a dense band of vibronic states via intramolecular phonon-assisted hopping on a nanosecond timescale is the dominant mechanism for excited-state decay. The data can be understood in terms of theoretical predictions for energy relaxation in disordered materials.
The Journal of Physical Chemistry, 1991
... Poly( hexy imethylsily iene) Copolymers William L. Wilson* and Timothy W. Weidman AT&... more ... Poly( hexy imethylsily iene) Copolymers William L. Wilson* and Timothy W. Weidman AT&amp;amp;amp; T Bell Laboratories, Murray Hill, New Jersey 07974 (Received: November 2, 1990) ... Chem.) 1986. 27, 109. (j) Schilling, F. C.; Bovey, F. A,; Ziegler, JM Macromolecules 1986, 19,2309. ...
Journal of the American Chemical Society, 1997
Broad-band irradiation (λ max ) 350 nm) of FvRu 2 (CO) 4 (1, Fv ) η 5 :η 5 -bicyclopentadienyl) r... more Broad-band irradiation (λ max ) 350 nm) of FvRu 2 (CO) 4 (1, Fv ) η 5 :η 5 -bicyclopentadienyl) resulted in rapid isomerization to colorless (µ 2 -η 1 :η 5 -cyclopentadienyl) 2 Ru 2 (CO) 4 (2) in a novel process involving a formal dinuclear oxidative addition to a C-C bond. The product reverted to 1 upon heating in solution or in the solid state, under the latter conditions with an enthalpy change of -29.8 (1.5) kcal mol -1 . Mechanistic studies with a mixture of 1 and 1-d 8 revealed the absence of label scrambling, pointing to intramolecular pathways. The quantum yield (0.15) was unaffected by the presence of CCl 4 , and no chlorination products were observed under these conditions. Irradiation of solutions of 1 or 2 with 300 nm light provided Fv(µ 2 -η 1 :η 5 -cyclopentadienyl) 2 Ru 4 (CO) 6 (6) or, in the presence of alkynes, the adducts FvRu 2 (CO) 3 (RCCR) (8-10, R ) H, C 6 H 5 , CO 2 CH 3 ). Heating 1 and PR 3 (R ) CH 2 CH 3 , CH 3 , or OCH 3 ) yielded FvRu 2 (CO) 3 (PR 3 ) (12-14), in which a fluxional process occurs characterized by intramolecular terminal to bridging carbonyl exchange. While 12 and 13 were inert, compound 14 rapidly and reversibly afforded the P(OCH 3 ) 3 -substituted analog of 2 (15) upon irradiation with UV light. The two diastereomeric 3,3′-di-tert-butyl-substituted fulvalene analogs of 1 (19) underwent the same reaction sequence with complete retention of stereochemistry, via the diastereomeric photoproducts 20. A double regiochemical labeling experiment proceeded with retention of connectivity and stereochemistry. A concerted mechanism for the photoisomerization is consistent with the experimental observations, but a biradical pathway cannot be ruled out. Kinetic data for the isomerizations of 2, 15, 20a, and 20b to their respective metal-metal-bonded Fv precursors were determined. The entropies of activation (+7 to +21 eu) suggested a disordered transition state. A sequence involving reversible CO loss was ruled out through a crossover experiment with 2-13 CO. Kinetic and labeling experiments point to a change in mechanism when the thermal reversion of 2 to 1 was run under CO (∼1 atm). The occurrence of ligand-induced C-C coupling was indicated through studies of the reactivity of 2 with P(CH 3 ) 3 . Photoisomer 2 reacts with excess CCl 4 to give FvRu 2 (CO) 4 Cl 2 ) by yet another mechanism. As in the potoisomerization of 1, the thermal reversion of 2 may follow a concerted pathway, although biradical intermediates cannot be excluded.
Advances in Resist Technology and Processing XII, 1995
ABSTRACT Silicon dioxide is the primary dielectric fabric of silicon integrated circuits, and the... more ABSTRACT Silicon dioxide is the primary dielectric fabric of silicon integrated circuits, and the need to pattern it accounts for a large percentage of all photolithographic operations. As shrinking device dimensions place extreme demands on both lithography and etching, patterned oxide films are finding yet additional applications as intermediate `hard masks.' For example, polysilicon gate and metal layers may be etched with greater selectivity and linewidth control through a thin patterned oxide mask, rather than through a thicker photoresist layer (which is used to pattern the oxide and removed before pattern transfer). However, any advantages of such schemes must be weighed against the costs of increasing process complexity. We recently reported a new all-dry photolithographic process based on the plasma deposition and patterning of organosilicon resists. These materials, as best exemplified by plasma polymerized methylsilane (PPMS), possess amorphous Si-Si bond backbone structures and undergo efficient photo-oxidation to give glasslike siloxane network material. Patterns are developed using chlorine plasma etching to selectively remove unexposed regions, providing a negative tone image. In previous papers we have demonstrated the use of these materials in bilevel processes, using oxygen reactive ion etching to transfer patterns in thin PPMS layers through underlying organic planarizing layers. Using 248 nm deep UV exposure tools, such schemes afford sub-0.25 micrometers design rule capabilities and are well suited for difficult device topography. Here we describe the discovery and development of a fundamentally different application unique to PPMS: a new direct approach to patterned silicon dioxide.
Optical/Laser Microlithography, 1993
ABSTRACT
Advances in Resist Technology and Processing X, 1993
Advances in Resist Technology and Processing XVI, 1999
ABSTRACT Some of the major limitations of top surface imaging schemes are now well documented: cr... more ABSTRACT Some of the major limitations of top surface imaging schemes are now well documented: critical dimension (CD) control across the wafer can be a serious issue as well as line edge roughness (LER). A primary focus of our work has been to investigate the performance of the 248 nm bi-level negative tone approach of the CVD photoresist process based on the plasma polymerization of methylsilane. In this paper, CD control data within a field and across the wafer are presented. CD control is shown to be very strongly dependent on the uniformity of the development step. The best results are obtained when using straight chlorine for the plasma etch development step.
Proceedings of SPIE - The International Society for Optical Engineering
Plasma polymerization of various mono- and di-substituted organosilanes (R1R2SiH2; R1 equals alky... more Plasma polymerization of various mono- and di-substituted organosilanes (R1R2SiH2; R1 equals alkyl, aryl and R2 equals H or alkyl) provides an effective approach to a new class of organosilicon resists useful in all dry photolithographic processing. For example, parallel plate rf plasma deposition systems may be used to deposit photosensitive films from low power discharges in methylsilane (MeSiH3) gas between 200 and 500 mTorr. Characterization by FTIR, UV-Visible, and NMR spectroscopy suggests that methylsilane undergoes predominantly dehydrogenative coupling reactions, giving Si-Si bonded network materials of general composition [(MexSiHy)n], with x and y between 0.5 and 1.0. Such films exhibit intense, near-UV absorption band edges characteristic of materials with Si-Si backbones, and undergo photo-oxidative crosslinking with bleaching when irradiated with mid-deep UV light ((lambda) < 365 nm) in the presence of oxygen.
Proceedings of SPIE - The International Society for Optical Engineering
We recently introduced a new class of high performance deep-UV photoresists which are deposited v... more We recently introduced a new class of high performance deep-UV photoresists which are deposited via the gas phase plasma polymerization of methylsilane. These materials, particularly plasma polymerized methylsilane (PPMS), undergo efficient oxidation on exposure to deep-UV light in air to form a glasslike siloxane network polymer, providing patterns which may be developed and transferred into underlying substrates using all dry plasma etch processes. Here we describe a simple new procedure which affords the opposite (positive) tone image in the same resist using a wet buffered oxide etch to remove exposed regions. Lithographic performance studies (dose latitude as well as linearity data) are presented for both the negative tone and the new positive tone versions of the process.
Journal of vacuum science & technology. B, Microelectronics and nanometer structures: processing, measurement, and phenomena: an official journal of the American Vacuum Society
Vapor phase pregate oxide surface preparation was studied in a high vacuum cluster tool. SiO 2 wa... more Vapor phase pregate oxide surface preparation was studied in a high vacuum cluster tool. SiO 2 was etched with anhydrous vapor hydrogen fluoride and methanol vapor. The oxide etch rate can be well controlled by varying wafer temperature, chamber pressure, and gas flow rates. A standard error of 5% in oxide etch rate has been achieved. Particles generated are less than ten per 125 mm wafer at an oxide etch rate of 60 Å/min. Atomic force microscopy measurements reveal no added Si surface microroughness attributable to vapor hydrogen flouride (HF) etching. Trace metallic contaminants such as iron and chromium were reduced with UV/Cl 2 based processes. A combination of vapor HF etching followed by UV/Cl 2 metal removal is an effective pregate oxide surface preparation. © 1995 American Vacuum Society
Proceedings., Sixth International IEEE VLSI Multilevel Interconnection Conference, 1989
ABSTRACT Drawing on advanced packaging and interconnection schemes along with advances in VLSI te... more ABSTRACT Drawing on advanced packaging and interconnection schemes along with advances in VLSI technologies, the authors consider some examples of novel interconnection technologies. Novel polymer waveguides requiring only exposure to deep UV to fabricate a waveguide are emphasized as a potentially important material compatible with overlaying complex VLSI circuitry. Superconducting microstrip interconnections are considered. These examples suggest that conventional VLSI silicon technologies will evolve to become the support for the selective introduction of advanced interconnection technologies, yielding within the smaller system volumes of wafer-level systems the heterogeneous mixture of technologies seen in, or being introduced into, conventional, complex systems. It is pointed out that the specific examples used are microfabricated structures on substrates appropriate for achieving narrow features
Ultrasonics, 1990
ABSTRACT We have studied the effects and applications of high intensity ultrasound in the reducti... more ABSTRACT We have studied the effects and applications of high intensity ultrasound in the reductive condensation synthesis of polysilanes and polysilynes, a new class of amorphous [RSi]n alkyl silicon network polymers. Best results were obtained in the sonication of liquid Na/K alloy with R2SiCl2 and RSiCl3 monomers. Sonochemically activated reactions in Na/K alloy-hydrocarbon emulsions proceed without the normal complications associated with surface passivation, and allow more precise control of reaction rate, stoichiometry, and polymer molecular weight. In the reactions of RSiCl3 monomers, sonication also decreases the tendency towards formation of insoluble and incompletely reduced network products. These procedures allowed the isolation of the first soluble polymers with the simple composition [RSi]n, (for R = alkyl substituents of at least three carbons). All spectroscopic data indicated these materials, termed polysilynes, are constructed primarily from (sp3) hybridized alkylsilyne [RSi] fragments, irregularly assembled via Si Si single bonds into random networks.
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1998
ABSTRACT The chemical vapor deposition resist film plasma polymerized methyl silane (PPMS) can be... more ABSTRACT The chemical vapor deposition resist film plasma polymerized methyl silane (PPMS) can be used as a single layer photoresist for optical lithography at 248 and 193 nm wavelengths. Upon exposure, the PPMS undergoes efficient photo oxidation in the presence of air to yield a siloxane network (PPMSO) giving patterns that can be dry developed using a chlorine-HBr plasma. After dry development, the PPMSO can be used to transfer a pattern through organic low κ materials, or can be converted to a silicon dioxide hardmask using a conventional resist stripper, then used to transfer patterns into polysilicon. © 1998 American Vacuum Society.
Nonlinear Optical Properties of Organic Materials III, 1990
Optical Interconnections and Networks, 1990
ABSTRACT Two important issues will greatly influence the success of mapping optical interconnecti... more ABSTRACT Two important issues will greatly influence the success of mapping optical interconnections into future waferlevel distributed computing systems: (1), the scalability of active optical devices with cointegration along side ULSI components, and (2), the scalability of optical networks and components to the wafer level. If these criteria can be met, planar integrated and free-space optics can potentially provide a very high performance communication network within the multi-wafer environment. With the predominantly planar geometry and processing of waferlevel circuits, process compatible integrated planar optical interconnections are especially attractive for providing network passive connectivity. As with their electrical counterparts, spatial, as well as time division multiplexing of optical interconnections is desirable, given that layout and area constraints are not too severe. Therefore here, emphasis is shifted away from the individual behavior of traditional long distance lightwave single mode waveguides towards the collective system behaviour (i.e. density, coupling, layout, etc.) of large dense arrays of multimode optical waveguides. In this paper, initial experimental optical coupling results are presented for arrays of multimode polysilyne polymer waveguides, both for straight configurations and for arrays with radial right angle bend layouts.
Advances in Resist Technology and Processing XV, 1998
ABSTRACT Plasma polymerized methylsilane resist films (PPMS) have high sensitivity to short wavel... more ABSTRACT Plasma polymerized methylsilane resist films (PPMS) have high sensitivity to short wavelength radiation. The photoinduced oxidation of PPMS films exposed in air forms siloxane network material (called PPMSO), allowing dry development by selective etching of the unexposed regions upon treatment with chlorine based plasmas. Negative-tone patterns of oxidized methylsilane thus formed can be consolidated in a standard resist stripper to form SiO2 like hard mask patterns. In this work, PPMS films are deposited using a commercial single wafer cluster tool dedicated to dielectric deposition. After exposure at 248 or 193 nm, PPMS development is performed in a commercial high density plasma source etcher. Oxide patterns obtained from PPMS films are used for organic resist patterning (bi-layer application) and gate stack patterning (single layer application).