Copolymers etching

Keywords Block copolymers Etching Nanolithography Nanoporous Self-assembly... 

Consistent with the PMCN homopol3nner results above, the MCN copolymers of Table VI exhibit PE etch rates intermediate to those of the two respective homopolymer values. When MCN is copolymerized with MCA, the resulting copolymers etch faster than PMCN and slower than PMCA (see Table VI). The etch rate is approximately linear with mole % MCA content this data Is plotted in Figure 2. 

When MCA is copolymerized with MMA, the resulting copolymer etches faster than PMMA, consistent with the PMCA and MCN/MCA results. Incorporation of MCA, a monomer with a-chlorine, has the effect of decreasing plasma etch resistance, as is observed for the MCA homopolymer. Sensitization by chlorine appears to be general (see Tables I, III, and VI), except for the case where the chlorine is Incorporated onto the aromatic side chain group. This effect was observed previously by Taylor and Wolf for other polymer systems. ( ) The C-Cl bond strength is lower than that for C-H and C-F, and there is much evidence that this bond can be easily cleaved, even in the solid state. (, ) This weaker side chain group leads to lower dry-etch resistance. 

Keywords Block copolymers Etch resistance Nanolithography ... 

Poly(phenylquinoxaline—arnide—imides) are thermally stable up to 430°C and are soluble in polar organic solvents (17). Transparent films of these materials exhibit electrical insulating properties. Quinoxaline—imide copolymer films prepared by polycondensation of 6,6 -meth5lene bis(2-methyl-3,l-benzoxazine-4-one) and 3,3, 4,4 -benzophenone tetracarboxyUc dianhydride and 4,4 -oxydianiline exhibit good chemical etching properties (18). The polymers are soluble, but stable only up to 200—300°C. 

Polystyrene-PDMS block copolymers4l2), and poly(n-butyl methacrylate-acrylic acid)-PDMS graft copolymers 308) have been used as pressure sensitive adhesives. Hot melt adhesives based on polycarbonate-PDMS segmented copolymers 413) showed very good adhesion to substrates with low surface energies without the need for surface preparation, such as etching. 

Copolymer Approach to Design of Sensitive Deep-UV Resist Systems with High Thermal Stability and Dry Etch Resistance... 

OXYGEN REACTIVE ION ETCHING (RIE) OF NOVOLAC-SILOXANE BLOCK COPOLYMERS... 

COPOLYMER STRUCTURE SILOXANE wt % Si O2 RIE rate1 (A/min) 02 ETCHING SELECTIVITY2... 

The incorporation of PDMSX into conventional novolac resins has produced potential bilevel resist materials. Adequate silicon contents necessary for O2 RIE resistance can be achieved without sacrificing aqueous TMAH solubility. Positive resist formulations using an o-cresol novolac-PDMSX (510 g/mole) copolymer with a diazonaphthoquinone dissolution inhibitor have demonstrated a resolution of coded 0.5 pm L/S patterns at a dose of 156 mJ/cm2 upon deep-UV irradiation. A 1 18 O2 etching selectivity versus hard-baked photoresist allows dry pattern transfer into the bilevel structure. 

TiCU readily functionalizes hydrophilic polymers such as poly(vinyl alcohol), m-ciesol novolac and methacrylic acid copolymers as well as moderately hydrophobic polymers such as poly(methyl methacrylate), poly(vinyl acetate), poly(benzyl methacrylate) and fully acetylated m-cresol novolac. HCI4 did not react with poly(styrene) to form etch resistant films indicating that very hydrophobic films follow a different reaction pathway. RBS analysis revealed that Ti is present only on the surface of hydrophilic and moderately hydrophobic polymer films, whereas it was found diffused through the entire thickness of the poly(styrene) films. The reaction pathways of hydrophilic and hydrophobic polymers with HCI4 are different because TiCl is hydrolysed by the surface water at the hydrophilic polymer surfaces to form an etch resistant T1O2 layer. Lack of such surface water in hydrophobic polymers explains the absence of a surface TiC>2 layer and the poor etching selectivities. 

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