Yousef Awad - Academia.edu (original) (raw)

Papers by Yousef Awad

Research paper thumbnail of Fabrication of x-ray masks using evaporated electron sensitive layers for back patterning of membranes

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, 2002

A process aimed at fabricating proximity x-ray lithography masks is presented. In this technique,... more A process aimed at fabricating proximity x-ray lithography masks is presented. In this technique, the Ta absorber layer is deposited and patterned on the back side of the membrane and nonspin-coated electron sensitive layers were used in order to achieve high resolution patterning of this absorber. The advantages gained by this approach include a reduction of the membrane temperature during the plasma etching step of the absorber patterns without using any cooling gas. This temperature reduction results from the direct contact of the membrane with a cooling plate. This approach also allows increased protection of the absorber patterns from contamination during exposure of the mask. A third advantage is that the smooth surface of the mask exposed to the wafer in the x-ray lithography stepper may also make it possible to reduce the gap between wafer and mask, thus achieving increased resolution with the x-ray lithography process.

Research paper thumbnail of Nanopatterning on fragile or 3D surfaces with sterol-based vapor-deposited electron beam resist

SPIE Proceedings, 2004

A novel and effective approach to nano-fabrication lithography is the vapour deposition of the ne... more A novel and effective approach to nano-fabrication lithography is the vapour deposition of the negative tone electron beam resists QSR-5 and QSR-15 (Quantiscript"s sterol based resist) onto a substrate. Vapour deposition is especially conducive for patterning thin delicate ...

Research paper thumbnail of Nano patterning on optical fiber and laser diode facet with dry resist

Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2004

Semiconductor micro and nanofabrication lithography techniques for application in microelectronic... more Semiconductor micro and nanofabrication lithography techniques for application in microelectronics as well as in micromechanics and optoelectronics can gain significantly from using a dry resist process, since it enables the deposition of a very uniform lithographically sensitive layer on a potentially very small area. This would otherwise be extremely difficult to achieve by using a traditional spin coated resist, such as poly(methylmethacrylate) (PMMA). We demonstrate the use of an electron sensitive sterol based evaporated electron beam resist to fabricate high-resolution features (down to 100 nm) on a small surface area. This electron beam resist has a sensitivity comparable to PMMA and is deposited using a simple thermal evaporation. Two practical applications are explored: first, this resist makes it possible to fabricate a Fresnel zone plate lens on the tip of an optical fiber in order to demonstrate the principle and the potential of highly efficient coupling of diode laser ...

Research paper thumbnail of Arrays of holes fabricated by electron-beam lithography combined with image reversal process using nickel pulse reversal plating

Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2004

A critical issue in fabricating arrays of holes is to achieve high-aspect-ratio structures. Forma... more A critical issue in fabricating arrays of holes is to achieve high-aspect-ratio structures. Formation of ordered arrays of nanoholes in silicon nitride was investigated by the use of ultrathin hard etch mask formed by nickel pulse reversal plating to invert the tonality of a dry e-beam resist patterned by e-beam lithography. Ni plating was carried out using a commercial plating solution based on nickel sulfamate salt without organic additives. Reactive ion etching using SF6/CH4 was found to be very effective for pattern transfer to silicon nitride. Holes array of 100 nm diam, 270 nm period, and 400 nm depth was fabricated on a 5×5 mm2 area.

Research paper thumbnail of Fabrication of X-Ray Masks Using the Silicon Direct Write Electron-Beam Lithography Process and Complementary Electron-Sensitive Resists

Japanese Journal of Applied Physics, 2002

In order to meet the long term goals of the International Technology Roadmap for Semiconductors, ... more In order to meet the long term goals of the International Technology Roadmap for Semiconductors, it is important to demonstrate that X-ray masks can be fabricated at resolutions well below the 100 nm barrier. This paper presents results on the use of conventional electron-sensitive resists and the silicide direct write electron beam lithography process (SiDWEL) for the fabrication of X-ray masks with sub-100 nm resolution. By optimizing the deposition of the thin films using conventional evaporators, the SiDWEL process was able to achieve linewidths of less than 40 nm and line spacing of less than 100 nm. The silicide patterns formed by the SiDWEL process are sufficiently resistant to plasma etching to directly transfer the patterns to the tantalum absorber. To improve the turnover time for mask fabrication, different writing schemes were studied, including combining the SiDWEL process with QSR-4, a novel negative resist designed specifically for this application.

Research paper thumbnail of Evaporated resist for the fabrication and replication of LEEPL mask

SPIE Proceedings, 2004

Masks for low energy electron proximity projection lithography (LEEPL) require thin membranes, wh... more Masks for low energy electron proximity projection lithography (LEEPL) require thin membranes, which in turn make the development of low-distortion masks a critical issue for this technology. By using an evaporated resist, a flip side fabrication process is presented ...

Research paper thumbnail of Fabrication of x-ray masks using evaporated electron sensitive layers for back patterning of membranes

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, 2002

A process aimed at fabricating proximity x-ray lithography masks is presented. In this technique,... more A process aimed at fabricating proximity x-ray lithography masks is presented. In this technique, the Ta absorber layer is deposited and patterned on the back side of the membrane and nonspin-coated electron sensitive layers were used in order to achieve high resolution patterning of this absorber. The advantages gained by this approach include a reduction of the membrane temperature during the plasma etching step of the absorber patterns without using any cooling gas. This temperature reduction results from the direct contact of the membrane with a cooling plate. This approach also allows increased protection of the absorber patterns from contamination during exposure of the mask. A third advantage is that the smooth surface of the mask exposed to the wafer in the x-ray lithography stepper may also make it possible to reduce the gap between wafer and mask, thus achieving increased resolution with the x-ray lithography process.

Research paper thumbnail of Nanopatterning on fragile or 3D surfaces with sterol-based vapor-deposited electron beam resist

SPIE Proceedings, 2004

A novel and effective approach to nano-fabrication lithography is the vapour deposition of the ne... more A novel and effective approach to nano-fabrication lithography is the vapour deposition of the negative tone electron beam resists QSR-5 and QSR-15 (Quantiscript"s sterol based resist) onto a substrate. Vapour deposition is especially conducive for patterning thin delicate ...

Research paper thumbnail of Nano patterning on optical fiber and laser diode facet with dry resist

Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2004

Semiconductor micro and nanofabrication lithography techniques for application in microelectronic... more Semiconductor micro and nanofabrication lithography techniques for application in microelectronics as well as in micromechanics and optoelectronics can gain significantly from using a dry resist process, since it enables the deposition of a very uniform lithographically sensitive layer on a potentially very small area. This would otherwise be extremely difficult to achieve by using a traditional spin coated resist, such as poly(methylmethacrylate) (PMMA). We demonstrate the use of an electron sensitive sterol based evaporated electron beam resist to fabricate high-resolution features (down to 100 nm) on a small surface area. This electron beam resist has a sensitivity comparable to PMMA and is deposited using a simple thermal evaporation. Two practical applications are explored: first, this resist makes it possible to fabricate a Fresnel zone plate lens on the tip of an optical fiber in order to demonstrate the principle and the potential of highly efficient coupling of diode laser ...

Research paper thumbnail of Arrays of holes fabricated by electron-beam lithography combined with image reversal process using nickel pulse reversal plating

Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2004

A critical issue in fabricating arrays of holes is to achieve high-aspect-ratio structures. Forma... more A critical issue in fabricating arrays of holes is to achieve high-aspect-ratio structures. Formation of ordered arrays of nanoholes in silicon nitride was investigated by the use of ultrathin hard etch mask formed by nickel pulse reversal plating to invert the tonality of a dry e-beam resist patterned by e-beam lithography. Ni plating was carried out using a commercial plating solution based on nickel sulfamate salt without organic additives. Reactive ion etching using SF6/CH4 was found to be very effective for pattern transfer to silicon nitride. Holes array of 100 nm diam, 270 nm period, and 400 nm depth was fabricated on a 5×5 mm2 area.

Research paper thumbnail of Fabrication of X-Ray Masks Using the Silicon Direct Write Electron-Beam Lithography Process and Complementary Electron-Sensitive Resists

Japanese Journal of Applied Physics, 2002

In order to meet the long term goals of the International Technology Roadmap for Semiconductors, ... more In order to meet the long term goals of the International Technology Roadmap for Semiconductors, it is important to demonstrate that X-ray masks can be fabricated at resolutions well below the 100 nm barrier. This paper presents results on the use of conventional electron-sensitive resists and the silicide direct write electron beam lithography process (SiDWEL) for the fabrication of X-ray masks with sub-100 nm resolution. By optimizing the deposition of the thin films using conventional evaporators, the SiDWEL process was able to achieve linewidths of less than 40 nm and line spacing of less than 100 nm. The silicide patterns formed by the SiDWEL process are sufficiently resistant to plasma etching to directly transfer the patterns to the tantalum absorber. To improve the turnover time for mask fabrication, different writing schemes were studied, including combining the SiDWEL process with QSR-4, a novel negative resist designed specifically for this application.

Research paper thumbnail of Evaporated resist for the fabrication and replication of LEEPL mask

SPIE Proceedings, 2004

Masks for low energy electron proximity projection lithography (LEEPL) require thin membranes, wh... more Masks for low energy electron proximity projection lithography (LEEPL) require thin membranes, which in turn make the development of low-distortion masks a critical issue for this technology. By using an evaporated resist, a flip side fabrication process is presented ...