Adamantyl methacrylate

Preparation of Poly(3-(l-Methacryloyloxy-l-Methylethyl)-2,6-Norbomanecarbolactone-co-2-Ethyl-2-Adamantyl Metbacrylate-co-3-Hydroxy-l-Adamantyl Methacrylate)... 

A reactor was charged with the Step 2 product (9.2 g), 2-ethyl-2-adamantyl methacrylate (7.4 g), 3-hydroxy-1-adamantyl methacrylate (8.3 g), AA -azobisisobutyroni-trile (60 mg), and 80 ml of THF and then stirred 20 hours at 60°C. After cooling the reaction mixture was added dropwise to 2 liter of methanol, and the precipitate was isolated by fdtration. The solids were washed with methanol and dried 19.9 g of product were isolated having a of 9800 daltons with a polydispersity of 1.80. 

I. Preparation of Poly(2-Ethyl-2-Adamantyl Methacrylate-co-p-Acetoxystyrene)... 

A reaction flask was charged with 2-ethyl-2-adamantyl methacrylate (0.24 mol), p-acetoxystyrene (0.56 mol), and isopropanol (279 g) and then heated to 75°C. This mixture was next treated with dimethyl-2,2 -azobis(2-methylpropionate) (0.048 mol) dissolved in isopropanol (22.11 g), stirred 20 minutes, and finally refluxed for... 

The entire Step 1 product was mixed with 4-dimethylaminopyridine and 239 g of methanol and then refluxed 20 hours. After cooling the mixture was neutralized with glacial acetic acid (0.133 mol) and precipitated in water. The precipitate was dissolved in acetone and then re-precipitated in water, the process being repeated three times. The precipitate was dried, and 102.8 g of polymer product were isolated, consisting of 70% p-hydroxystyrene and 30% 2-ethyl-2-adamantyl methacrylate with a of 8200 daltons and polydispersity of 1.68. 

A reaction kettle was charged with propylene glycol monomethyl ether acetate (5.1 g) and propylene glycol monomethyl ether (3.4 g) and then heated to 80°C. This mixture was next treated dropwise with the Step 1 product (2.7 g), 3-hydroxyadamantane methacrylate (4.7 g), 2-methyl-2-adamantyl methacrylate (7.0 g), y-butyrolactone methacrylate (6.8 g), and the free radical initiator V-601. Thereafter the reaction proceeded for 2 hours at 80°C and was then cooled and poured into a 720 ml mixture of hexane containing 80 ml of EtOAc. The precipitate was collected, and 18 g of product were isolated having a Mw of 10,700 daltons with a polydispersity of 1.81. 

We have observed similar effects in the TREPR spectra of the polymeric radical of poly(adamantyl methacrylate) (PAMA, spectrum not shown). Earge ester side chains such as the adamantyl and fluorinated alkyl groups experience a larger amount of hydrodynamic friction than do smaller side chains such as methyl and ethyl groups. ... 

Several polymethacrylates, primarily alkyl esters, were compared with a novolac resist in terms of etch rates in CF4 and Ar plasmas. The alkyl groups examined included methyl, terf-butyl, cyclohexyl, norbonyl, adamantyl, and benzyl [226]. The polymerization of alicyclic methacrylates was pioneered by Otsu, who has demonstrated facile polymerization of bulky methacrylates and reported high Tg of this class of polymethacrylates [230]. It has been found that alicyclic polymers exhibit better dry etch resistance than acyclic esters and that the dry etch durability is increased by an increase in the number of rings. Thus, poly(adamantyl methacrylate) is as stable as a novolac resist under dry etch conditions. A 30/70 copolymer of adamantyl methacrylate with ter/-butyl... 

Chart 9.5 Structure of poly[/V-(l-adamantyl)vi-nylsulfonamide-co-(2-methyl)adamantyl methacrylate], a random copolymer that absorbs light only weakly at 2=193 nm [33]. 

Forman et compared a series of linear and star-block copolymers resist, prepared using the same scheme, for exposure at 193 nm (ArF resist). The star copolymers developed had as a core an oligoinitiator based on saccharose from which three standard ArF photoresist monomers, a-y butyrolactone methacrylate (GBLMA), methyladamantyl methacrylate (MAMA), and hydroxyl adamantyl methacrylate... 

The etch resistance of common acrylic polymers is poor but can be improved without reducing 193-nm optical transparency by the attachment of alicyclic pendant groups to the backbone. For example, a 1 1 copolymer of tert-butyl methacrylate and adamantyl methacrylate (108) exhibits a nearly twofold reduction in plasma etch rate compared to the ert-butyl methacrylate homopolymer. Figure 15b provides examples of alicyclic ester groups that have been assessed (109-111). 

Poly(5-p-menthyl methacrylate) exhibits an intermediate value. It has the most flexible, yet most bulky substituent since no bridging is present. Poly(isobomyl methacrylate) has the lowest Coo value its substituent, which is bridged, is more rigid but smaller than the menthyl group. Poly(l-adamantyl methacrylate) with a doubly bridged ring has the largest C. Probably, the observed C o variations could not be predicted. 

Ishizone, T., Tajima, H., Torimae, H., and Nakahama, S. (2002) Anionic polymerizations of 1-adamantyl methacrylate and 3-methacryloyloxy-l,l -biadamantane. Macromolecular Chemistry and Physics, 203,2375 2384. 

Fukuhara, T., Shibasaki, Y., Ando, S., Kishimura, S., Endo, M., Sasago, M., and Ueda, M. (2005) Synthesis of Poly[N-(l-adamantyl)vinylsulfonamide-co-2-(2-methyl)adamantyl methacrylate] for 193nm lithography. Macromolecules, 38, 3041. 

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