Negative electron beam resists resolution

Many reports have been published on negative electron-beam resists. Most of these resists utilize radiation-induced gel-formation as the insolubilzation reaction. However, a major problem with these resists, is that their resolution is limited by swelling which is induced by the developer during development. 

Taniguchi, Y. Hatano, S. Shiraishi, S. Horigone, S. Nonogaki, and K. Naraoka, PGMA as a high resolution, high sensitivity negative electron beam resist, Jpn. J. Appl. Phys. 18, 1143 (1979). 

When some or all of the phenyl rings are substituted with halogen (Scheme 6.11), the radiation sensitivity and the cross-linking efficiency of polystyrene can be enhanced significantly. Negative electron-beam resist formulated from iodi-nated and chlorinated polystyrene and based on this approach have been reported. Sensitivity of about 2 p.C/cm and resolution of about 1-p.m features have been demonstrated with these materials. ... 

The major advantages of electron-beam lithography over conventional photolithography are a higher potential resolution and the possibility of direct beam writing on the resist surface. In addition to the usual requirements discussed earlier, positive or negative electron-beam resists have to possess the following properties ... 

Pol ene (PS) is a negative deep UV (25) and electron beam resist showing high resolution (24) but low sensitivity (25). Apparentty no attempt has been made to improve the sensitivity of PS by adcUtion of a bisazide. We expected that addition of bis-PFPA to PS should result in a deep-UV resist with increased sensitivity. Thus, various amounts of bis-PFPA 1 or 2 and the corresponding nonfluorinated bisazide 3 or 4 were separately added to PS. The resist solutions were then spin-coated on NaQ discs, baked, photolyzed and developed. The intensity of the IR CH stretching absorption at 2924 cm" before and after development was used to estimate the retention of film thidcness. 

We have developed a new silicone based negative resist (SNR) by introducing the chloromethyl group into polydiphenylsiloxane. SNR has a high Tg (170 C), good electron beam sensitivity and excellent durability to 02 RIE (9). In this paper we describe the SNR preparation and characteristics, and demonstrate a high resolution of 2LR system using this resist. 

A new silicone-based negative resist (SNR) for two layer resist systems was designed and prepared. It showed excellent dry etching durability to 02 RIE, high sensitivity to electron beam, X-ray and deep UV, and high resolution. Two layer resist with SNR/AZ resist is very effective to achieve submicron patterns with high aspect ratio, and will be used for the fabrication of submicron patterns over topography such as the metallization of electrode patterns in the last step of VLSI fabrication process. 

Electron Beam Microliihography Good sensitivity and contrast, acceptable plasma etching resistance less scattering of electrons aiul therefore better resolution negative and positive resists possible. 

The hexaacetate of 6 has been tested as a high resolution negative resist for electron beam lithography, showing sufficient resolution to be useful for nanoscale device processing. Quantum confined cadmium sulfide clusters are stabilized by the Mannich base calixarenes 195 (R = Me, Bu, cyclohexyl). ... 

An electron beam is of much shorter wavelength than the radiation used in standard microlithography and, therefore, provides greater resolution possibilities. For resist exposure a beam of electrons can be used whose position is controlled by a computer-driven beam deflector, thus obviating the need for a mask. Both positive- and negative-working resists are used for electron beam lithography. 

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