Resolution electron resists

Recently chloromethylated polystyrene (CMS), a highly sensitive, high resolution electron resist with excellent dry etching durability, was developed. Very recently reactive intermediates in irradiated polystyrene, which is a starting material of CMS, have been studied and the transient absorption spectra of excimer (2-4), triplet states (2,5), charge-transfer complexes, and radical cations (6) of polystyrene have been measured. The present paper describes the cross-linking mechanism of the high sensitivity CMS resist and compares it to that of polystyrene on the basis of data on reactive intermediates of polystyrene and CMS. 

Ultrathin LB PMMA and novolac/diazoquinone films have been demonstrated to act as high resolution electron beam and optical resists, respectively. Structural rearrangements in the LB PMMA films have been observed by using fluorescence spectroscopy. However, this rearrangement did not appear to influence the lithographic performance when seven or more layers of LB PMMA films were used as the resist. A more comprehensive study of the relationship between lithographic performance and LB film structure is currently underway. 

The experiments were performed in stainless steel UHV chambers which were equipped with the instrumentation necessary to perform Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS), UV Photoelectron Spectroscopy (UPS), Low Energy Electron Diffraction (LEED), work function measurements (A( )), High Resolution Electron Energy Loss Spectroscopy (HREELS), and Temperature Programmed Desorption (TPD). The Au(lll) crystal was heated resist vely and cooled by direct contact of the crystal mounting block with a liquid nitrogen reservoir. The temperature of the Au(lll) crystal was monitored directly by means of a... 

These vinyl systems were chosen also because they function as high-resolution electron beam resists and deep UV resists at X<300 nm. 

The progress of technology for the high-resolution fabrication of semiconductor and magnetic bubble devices has required sub-micron exposure techniques such as electron beam x-ray and deep UV. Although a number of papers have been published on electron beam resists, reaction mechanisms of electron resists are still largely unknown since few studies on reactive intermediates by means of direct measurements have been done in order to elucidate the reaction mechanisms. 

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... 

The LDPE production with tubular reactors (see Section 5.1) requires some sophisticated control valves [45]. The let-down valve (Fig. 4.2-6 B) controls the polymerization reaction via the pressure and temperature by a high-speed hydraulic actuator (9) together with an electronic hydraulic transducer. The position of the valve relative to the stem is determined by a high-resolution electronic positioner (7). The cone-shaped end of the valve stem (2), as well as the shrunk valve seat (3) are made from wear-resistant materials (e.g., sintered tungsten carbide) in order to tolerate the high differential pressure of around 3000 bar during the expansion of the polymer at that location. 

Poly (butene-1 sulfone (PBS) is a highly sensitive, high-resolution electron-beam resist (1-2) which is used primarily as a wet-etch mask in the fabrication of chrome photomasks. PBS has found little use as a dry-etch mask because of its lack of etch resistance in plasma environments (3-8). This primarily stems from the fact that PBS depolymerizes in such an environment which greatly enhances the rate of material loss from the film. Moreover, depolymerization is an activated process which causes the etching rate to be extremely temperature dependent. Previous work (3,7) has shown that the etch rate of PBS in fluorocarbon-based plasmas varies by orders of magnitude for temperature differentials of less than 30 C. 

From the NMR tracer desorption and self-diffusion data (second and third lines of Table I), one obtains the relation Timm > TmlL. In the example given, intercrystalline molecular exchange is limited, therefore, by transport resistances at the surface of the individual crystals. Combined NMR and high-resolution electron microscopy studies 54) suggest that such surface barriers are caused by a layer of reduced permeability rather than by a mere deposit of impenetrable material on the crystal surface, although that must not be the case in general. 

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. 

The fabrication of LSI circuits, and of VLSI circuits in particular, requires patterns of micron and submicron dimensions, and consequently polymer resists with a high degree of resolution (1). So far the most frequently used positive electron resist has been poly(methyl methacrylate) (PMMA), which affords a high resolution power together with a relatively good thermal stability (2-4) A serious limitation of PMMA with respect to the efficiency of the electron lithography system is its low sensitivity to electron irradiation ( 10-5 - 10 4c/cm2). For the preparation... 

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). ... 

---