KrF photoresist polymers (PASTMs) were prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization. Four (meth)acrylates with lithographic functionalities including styrene ...(St), 4-acetoxystyrene (AST), 2-methyl-2-adamantyl methacrylate (MAMA), and tert-butyl acrylate(TBA) were used as monomer components and 2-methyl-2-(dodecylsulfanylthiocarbonyl) sulfanylpropanoic acid (MDFC) was used as RAFT agent, varying the RAFT content could modulate molecular weight. Fourier-transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (
1
H NMR) indicated that the synthesis was successful. Gel permeation chromatography (GPC) showed that the molecular weight decreased with the increased content of MDFC, and all the polymers possessed weight-average molecular weight below ten thousand and polydispersity less than 1.32. Thermogravimetric analysis (TGA) characterized the thermal properties, the results implied that initial thermal decomposition temperature reached 200 °C, which could satisfy the lithography process. Differential scanning calorimetry (DSC) showed that the Tg decreases with molecular weight. The RAFT polymerization kinetics plots demonstrated that the polymerization was first-order, the number-average molecular weights of the polymers with relatively low polydispersity index values increased with total monomer conversions indicating that the concentration of growing radicals was constant throughout the polymerization process. The narrow molecular weight distribution and composition uniformity of the polymers prepared by RAFT polymerization could be beneficial for lithography, after alcoholysis, lithography evaluation under KrF lithography showed that this homogeneous polymer photoresist exhibited better space and line (S/L) pattern with resolution of 0.18 μm according to the SEM image.
Xanthate-mediated reversible addition–fragmentation chain transfer (RAFT) methodologies have been applicable to preparation of branched or star polymers. In this article, novel star copolymers have ...been synthesized through xanthate-mediated RAFT polymerization with p-acetoxystyrene and tert-butyl acrylate. Fourier transfer infrared, nuclear magnetic resonance spectra, and gas chromatography analyses indicated that the polymerization was successful between both of the monomers and the star RAFT agent. The intrinsic viscosity and Zimm branching factor (g′) were used to confirm the copolymers’ architecture. The ultraviolet absorbance of the copolymer solutions indicated that the copolymer was suitable for use as a krypton fluoride (KrF) laser photoresist. Moreover, the photolithography performance of the positive-tone chemically amplified photoresist was evaluated. The results indicated that the photosensitive based on the star copolymer was higher than the linear one, and the pattern resolution was around 200 nm at a low exposure energy.
Two kinds of UV-curable polyurethane acrylates (PCDL-H-PUA and PCDL-P-PUA) were synthesized starting with polycarbonate diols (PCDL), isophorone diisocyanate and dimethylolpropionic acid and ...terminated with hydroxyethyl methacrylate or pentaerythritol triacrylate to impart mono-methacrylate or tri-acrylate end-group functionality, respectively. The structures and properties of the products were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, gel permeation chromatography and thermogravimetric analysis. The average molecular weights were between 7500 and 9300 g/mol, and the thermal properties of the products were excellent. The influence of the functionality of the end-capping functional group on the UV-curing behavior was investigated using real-time spectroscopy. Results showed that curing rate and conversion of PCDL-P-PUA were higher than those of PCDL-H-PUA, and the final double bond conversion of the polymers reached 95 %. PCDL-H-PUA and PCDL-P-PUA were applied to negative photoresists as the main film resin. The resolution of the optimal photoresist reached 40 µm.
Cholic acid is a class of biological compounds that exhibit valuable properties, and have been applied in many fields due to its special chemical structures for many areas. In this study, ...poly(methacrylic acid tert-butyl cholate ester)-
co
-(acetoxy styrene) P(MATC-
co
-AS) was synthesized from cholic acid, then the final copolymer poly(methacrylic acid tert-butyl cholate ester)-
co
-(p-hydrostyrene) P(MATC-
co
-HS) was obtained after P(MATC-
co
-AS) was hydrolysized. The structure and properties of the copolymers were determined through nuclear magnetic resonance, gel permeation chromatography, UV spectrometry, thermogravimetric analysis, and differential scanning calorimetry. The ultraviolet spectra of the copolymers indicate that they exhibit excellent optical transmittance at 248 nm. Moreover, the photolithography performance of a positive-tone photoresist based on the copolymers were evaluated using an KrF laser exposure system. The results indicate that a resolution of 0.25 μm could be achieved at a low exposure dose.
A series of copolymers Poly (TBA-CA-St-ASM)(PTCSA) were synthesized via precipitation polymerization by using tert-Butyl acrylate (TBA), Styrene (St), p-acetoxy styrene (ASM), and cedryl methacrylate ...(CA) as co-monomer. Then, Poly (TBA-CA-St-HS)(PTCSH) was prepared in the presence of sodium methoxide in methanol. The fourier transfer infrared (FT-IR) spectra and proton nuclear magnetic resonance (
1
H–NMR) spectra indicated that the synthesis was successful. The molecular weight, glass transition temperature (T
g
) and thermal decomposition temperature (T(10%)) of the copolymers increased with the addition of CA. Moreover, a positive-tone chemically amplified Krypton Fluoride (KrF) photoresist was prepared, and the photolithography performance of the photoresist was evaluated using a KrF laser exposure system, the result showed that the resolution could reach the level of 0.25 μm.
A series of novel branched methacrylate copolymers (BPMBMV) were synthesized via the mercapto chain transfer polymerization using methacrylic acid, maleic anhydride, benzyl methacrylate, and 4-vinyl ...benzyl thiol. Then, BPMBMV reacted with hydroxyethyl acrylate to obtain branched UV-curable copolymer H-BPMBMV, which were characterized by fourier transfer infrared spectra and proton nuclear magnetic resonance spectra. The molecular weights and glass transition temperature (
T
g
) of the polymers decreased with the addition of VBT. The results of photo-differential scanning calorimetry (Photo-DSC) tests showed that photo-polymerization ability of H-BPMBMV increased with the increased content of VBT. With an optimized formulation, a negative-type photoresist was prepared. The resolution of the circuit could reach as high as 20 μm, and the film of photoresist showed good acid resistance.
tert
-Butyl acrylate (TBA), benzyl methacrylate (BzMA) and acrylic acid (AA) were used to synthesize prepolymer (PTBA) with carboxyl pendant through free-radical polymerization. Glycidyl methacrylate ...(GMA) was then added to react with carboxylic acid group of PTBA to form UV-curable copolymer PTBA-G. Proton Nuclear magnetic resonance (
1
H NMR) and Fourier transform infrared spectroscopy (FTIR) were used to confirm the structure and functional group of prepolymer and copolymer, GPC was employed to determine the molecular weight and polydispersity. Real-time infrared and photo differential scanning calorimetry (photo-DSC) were used to evaluate the UV-curable kinetics of copolymer, thermo-gravimetric analysis (TGA) showed the thermal stability of the copolymers increased as the GMA content increase. When the ratio of GMA and AA was 0.3, it showed excellent resolution of 50 μm by SEM observation.
