Negative electron resist properties

Table VIII. Lithographic Properties of Selected Negative Electron Resists...

To achieve a manufacturable system for sub-0.5-pm patterning, extremely precise control of the molecular properties, structure, composition, and purity of the polymer is required (Table 4). Meeting these requirements provides intellectual challenges in ultrapurification reaction engineering and chemical synthesis. An illustration of the control required in this synthesis process can be found in a negative electron beam resist, GMC. 

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 ... 

There are many photoresists available commercially. These can be categorised into positive and negative tone resists. Various formulations of resists have differing properties (viscosity, ultimate achievable resolution, substrate adhesion etc.). Several classes of resist have thus been developed for different electronic applications. For example, high-resolution photolithography for patterning of submicron transistors requires a different resist to that needed for deep silicon etching of micro-electro-mechanical-systems (MEMS) stmctures. 

The photoresponsive properties of molecular glasses also have been applied in the design of resists for semiconductor lithography. In a resist, irradiation changes the solubility of the materials, making it more or less soluble (positive or negative resist, respectively). The search for new resist materials follows the development of lithographic techniques toward deep-UV and electron beam... 

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