Direct-write electron lithography

Of the reported materials, the only commercially available resists are one of the MMA-MAA/MMA-MACl compositions and a t-butyl methacrylate copolymer material (13). In this work, we have chosen to examine the copolymer mixture, which crosslinks at a temperature of 160°C compared to 250 C for the single copolymer. We have carried out experiments to optimize its use for direct write electron beam lithography. 

The two principal modes of operation of electron-beam exposure systems include the maskless direct-write electron-beam machines and the mask-based electron-beam machines. Direct-write electron-beam machines operate directly from design data and are capable of extremely high resolution. Mask-based electron-beam systems utilize masks in their imaging process. The implementation of electron-beam lithography in mix-and-match mode with optical lithography in a manufacturing environment has been demonstrated. 

The current technological competition for practical fabrication of 0.5 - 1.0 pm feature is in between photolithography and electron beam direct writing, and between single layer and multi-level resist. For less than 0.5 pm, the use of electron beam writing with multilevel resist will be inevitable. Further developments in electron resists from the standpoint of both resist chemistry and process development will be necessary to establish the electron beam lithography. 

It is equally worthy to note that a resist based on hydrogen silesquioxanes (HSQs) and formulated in methylisobutyl ketone (MIBK) carrier solvent has recently been reported to have demonstrated pitch resolution down to 20 nm in a 30-nm-thick HSQ film with electron-beam direct-write lithography (exposure... 

In electron-beam direct-write lithography, the scanning electron beam of the exposure systems is focused to a small spot that is controlled [i.e., deflected and turned on and off (blanked)] by a computer as it is scanned across the surface of the resist film. Masks are not used in this exposure process. Two beam-forming approaches are employed. The first uses a Gausssian round beam. The second... 

In order to address the low throughput issues of electron-beam direct-write lithography, without multiple columns and the attendant complexity, electron... 

The main advantage of NIL techniques, over direct-write techniques such as electron beam lithography, is that NIL can be used for rapid replication of nanoscale features on a wafer substrate. There are several variations of NIL, developed by different manufacturers of NIL systems. The following sections give a brief overview of some of the most important concepts of NIL. 

Electron beam lithography is a direct-write method in which a focused beam of electrons is directly scanned over the resist [4,5]. No mask is required as the pattern... 

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