Negative Tone Resists Research Articles

Evaluation of ma-N 2400 series DUV photoresist for electron beam exposure

Several DUV positive and negative tone resists were developed for the photolithography at wavelengths of 248 nm and shorter. Most of these DUV photoresists are sensitive to electron beam exposure, too. In this paper the results of electron beam exposure of the negative tone ma-N 2400 series DUV photoresist will be presented. This resist has no chemical amplification and no critical process steps. Further, the resist provides a good resistivity to plasma etching processes, so that it can be used successfully for etch and lift-off processes. The necessary exposure doses for the resist layers spincoated with thicknesses between 0.3 and 0.8 @mm on silicon wafers were in the range between 60 and 120 @mC/cm^2. The exposed resist was developed with the metal ion free developer MIF 726. Patterns down to the low submicrometer region were generated. Developing properties, sensitivities and resolution of the electron beam exposed ma-N 2400 series resist tested under various conditions will be presented.

Fullerene Derivatives as Novel Resist Materials for Fabrication of MEMS Devices by Electron Beam Lithography

AbstractThe fabrication of MEMS and electronic devices relies heavily on lithography. We have explored the application of derivatives of C60, as high resolution, high etch durability resists. Spin coating was used to produce films of various methanofullerenes on silicon substrates, with thickness ranging from 20 to 200 nm. These films behave as effective high resolution negative tone electron beam resists allowing sub 20 nm patterning of silicon which compares favorably with other negative tone resists. Organic solvents such as monochlorobenzene and chloroform can be used to develop the exposed films. The films have sensitivities of 4 × 10−3 to 8 × 10−4 C/cm2 for 20 keV electrons, more than an order of magnitude higher than the sensitivity of C60,. The dry etch durabilities of these compounds are considerably higher than those of conventional resists. A silicon grid with hole depth 160 nm and wall thickness 20 nm has been fabricated to demonstrate the high resolution and high etch durability of these resists.

A Water-Castable, Water-Developable Chemically Amplified Negative-Tone Resist

This paper describes an “environmentally friendly”, water-castable, water-developable photoresist system. The chemically amplified negative-tone resist system consists of three water-soluble components: a polymer, poly(methyl acrylamidoglycolate methyl ether), [poly(MAGME)]; a photoacid generator, (2,4-dihydroxyphenyl)dimethylsulfonium triflate, and a cross-linker, 1,4-butanediol. In the three-component resist system, the acid generated by photolysis of the photoacid generator catalyzes the cross-linking of poly(MAGME) in the exposed regions during postexposure baking, thus rendering the exposed regions insoluble in water. Negative-tone relief images are obtained by developing with pure water. The resist is able to resolve 1 μm line/space features (1:1 aspect ratio) with a deep-UV exposure dose of 100 mJ/cm2 (dose to print). The resist can be used to generate etched copper relief images on printed circuit boards using aqueous sodium persulfate as the etchant. The mechanism of cross-linking has been inves...

Photosensitive polyimides consisting of simple mixtures of 4‐substituted diazonaphthoquinones and polyamic acids

AbstractPolyimide resists that can be developed with a basic aqueous solution were produced by simple mixtures of conventional polyamic acids and naphthoquinone diazides in which sulfonate groups are substituted at the 4‐position. The diazonaphthoquinones bearing electron‐withdrawing groups gave negative tone resists. On the other hand, those bearing electron‐donating groups gave positive tone resists. The difference in the resist behaviors depending on the photoactive structure was explained by crosslinking caused by photogenerated sulfonic acids. The thermal stability of polyimides prepared from the resists was almost the same as that of conventional polyimides.

Computer-aided resist modelling with extended XMAS in x-ray lithography

There is an increasing need for computer-aided lithography simulation and modelling in IC manufacture. Software programs are well-established tools in simulating the problems affecting line-edge profiles for different exposure arrangements and development processes. The simulation program XMAS (X-Ray Lithography Modelling and Simulation) is designed to evaluate a large variety of exposure and development situations in X-ray lithography. After the imaging procedure, a simulation of the development process can be performed resulting in two or three-dimensional resist profiles at various stages in the process. Results are presented concerning the development behaviour of standard and experimental positive three-component-system (3CS) resists as well as experimental negative tone resists. The influence of secondary electrons backscattered from different substrate layers is investigated. The algorithm for three-dimensional development based on a ray-tracing formalism is described.

The growth of semi-insulating gallium arsenide by the LEC process : B. Lent, M. Bonnet, N. Visentin and J. P. Duchemin. Microelectron. J.13 (1), 5 (1982)

Several DUV positive and negative tone resists were developed for the photolithography at wavelengths of 248 nm and shorter. Most of these DUV photoresists are sensitive to electron beam exposure, too.In this paper the results of electron beam exposure of the negative tone ma-N 2400 series DUV photoresist will be presented. This resist has no chemical amplification and no critical process steps. Further, the resist provides a good resistivity to plasma etching processes, so that it can be used successfully for etch and lift-off processes.The necessary exposure doses for the resist layers spincoated with thicknesses between 0.3 and 0.8 μm on silicon wafers were in the range between 60 and 120 μC/cm2. The exposed resist was developed with the metal ion free developer MIF 726. Patterns down to the low submicrometer region were generated.Developing properties, sensitivities and resolution of the electron beam exposed ma-N 2400 series resist tested under various conditions will be presented.