Norbornene-sulfur dioxide

Polymers for use in 193 nm lithography are co-, ter-, and tetra-polymers of 1) methacrylates, 2) norbornenes, 3) norbornene-maleic anhydride, 4) nor-bornene-sulfur dioxide, and 5) vinyl ether-maleic anhydride (Fig. 39). While 1), 3), 4), and 5) are prepared by radical polymerization, all-norbornene polymers 2) are synthesized by transition-metal-mediated addition polymerization [166-168].Norbornenes (Fig.40) are sluggish to undergo radical [168,169] and cationic [170] polymerizations. Their ring-opening metathesis polymerization (ROMP, Fig. 40) [ 171 ] has never produced worthy resist polymers. The C=C double bonds introduced in the ROMP polymer backbone must be hydrogenated to reduce the 193 nm absorption and the ROMP polymers tend to have low Tg. However, the major problem for the ROMP polymers was their unacceptable swelling in aqueous base development. While polymethacrylate systems contain etch-resistant alicyclic structures in the ester side chain, norbornene-based systems carry the alicyclic unit in the backbone. Essentially all the 193 nm re-... 

A terpolymer of norbornene hexafluoroisopropanol, sulfur dioxide, and CBN (see Scheme 7.40) has been reported to be highly transparent at 193 nm (optical density 0.25/p.m) and successfully used in 193-nm resist application. ... 

Radical Co- and Terpolymerization of Norbornenes with SO2. A typical polymerization procedure is described below. The fluoroalcohol monomer la (2.74 g, 0.01 mol) was placed in 25 mL of liquid sulfur dioxide at -60 to which were added... 

The compound NO has been also widely used [17, 20, 101] to detect radicals spectroscopically in degraded polymer. The effect of radical acceptors in mechanochemistry is described in Section III.H. The use of a mixture of norbornene and sulfur dioxide has also been suggested as one of the most sensitive detectors of free radicals thus far discovered [137]. 

The extreme reactivity of norbornene plus sulfur dioxide has been shown in high-speed stirring experiments conducted by Sartori and Lundberg [155]. They showed that the reaction was not spontaneous but could be activated by macroradicals caused by shearing of polyisobutylene in the solution. Block copolymers were formed. They showed also that this polymerization may be one of the fastest radical reactions known and may well serve as a sensitive detector for radical generation [155]. 

Electrolysis of benzothiete sulfone 269 yields the phenylmethanesulfinate anion (major) and the o-toluenesulfinate anion (minor).Thermolysis 618,619 gj. photolysis of thiete 1,1-dioxides proceeds via ring-opening to vinyl sulfines, for example. 288, which have been trapped by reaction with water, phenol,methanol, or norbornenes. These intermediates may recyclize to unsaturated sultines (cyclic sulfinate esters) (e.g., 289) or lose sulfur monoxide to give mainly the trans isomers of a,j3-unsaturated carbonyl compounds (e.g., 290). Mass spectra also indicate the formation of unsaturated sultines. ... 

---