Electron resists negative

The second type of internal resistance is electrical resistance—r2- The influences of temperature and electrolyte thickness on electronic internal resistance of the electrolytes are not well known. The electronic conductivity values of solid oxide electrolytes are spread across a very wide range. They do not have a major impact on calculated cell voltage for high fuel utilization factors. It is hard to measure the electronic resistance of solid oxide electrolytes since they have both conductivities (ionic and electronic) simultaneously, which gives total electrical resistance. It should be noted that decreasing electrolyte thickness reduces ionic resistance (positive effect), but also probably reduces electronic resistance (negative effect). 

Figure 30. Exposure curves for COP negative electron resist on three substrate materials.

Figure 4. Typical response or sensitivity curve for a negative electron resist. The value of Dg is obtained from Figure 3 and usually occurs at 0.5 - 0.7 normalized thickness.

Figure 21. Scanning electron beam micrographs of COP negative electron resist patterns developed in two different ketone-alcohol mixtures.

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

As a general rule, the sensitivity of conventional electron beam resists is not sufficient for economic throughput in an x-ray lithographic system. This is particularly true of positive electron resists such as PMMA, the most widely used x-ray resist for experimental purposes, whose sensitivity of >500 mJ/cm2 is some 100 times too slow for practical application. Even PBS only shows a sensitivity of 94 mJ/cm2 to PdLa x-rays. Consequently, the major research effort has concentrated on negative resists because of their higher inherent sensitivity. 

The scheme of radiation-induced reactions of CMS, negative electron resist, is proposed as follows on the basis of the present pulse radiolysis data. 

Figure 7 shows the SEM photographs of line and space patterns using an exposure of 10 / 2. The smallest line and space width of the 2LR pattern that was well-resolved is 0.2 . Figure 8 shows the resolution of 1LR poly-a-methylstyrene (aM-CMS) pattern and the 2LR using SNR/AZ resist. In the case of aM-CMS that is known as a high resolution negative electron resist in 1LR, the smallest line and space width is 0.4 jtm with 0.6 jim of resist thickness... 

Table III. Polymers for representative negative electron resists...

Many negative electron resists recently developed for dry-etching processes are based on the polystyrene (PSt) structure because of the relatively high stability against dry-etching reactions and high Tg of PSt. Another advantage of PSt is the availability of nearly mono-dispersed polymer. 

High resolution resists In the case of negative electron resists, the requirement of high sensitivity and high resolution, is mutually incompatible, because both are strong function of molecular weight of resist polymer but in opposite directions. 

Poly (chloromethylstyrene-co-2-vinylnapthalene) has been developed as a negative electron resist. 

A feasibility of designing a dry etch resistant negative electron resist was discussed by Thompson et al. ( 5 ). They discussed parameters affecting negative resist characteristics in a quantitative way. 

Sensitivity. Poly(2-vinylnaphthalene) is a low sensitive negative electron resist, and Dg-M value for the polymer was estimated as 10 Og /cm2-mole ( 9 ). Froduct Dg Mw is. a constant that characterizes the sensitivity for negative resists, where Dgand Mw denote gel dose and weight average molecular weight, respectively ( 6 ). To attain higher sensitivity, modification or copolymerization with other sensitive monomers is needed. 

Poly(butadiene-co-glycidyl methacrylate) as Negative Electron Resist... 

---