Improved method for measuring photoacid generator kinetics in polymer thin films using normalized interdigitated electrode capacitance data

Abstract

Articles you may be interested inOn the design of capacitive sensors using flexible electrodes for multipurpose measurements Rev. Sci. Instrum. 78, 043903 (2007); A high precision method for measuring very small capacitance changes Rev.A precision capacitance cell for measurement of thin film out-of-plane expansion. I. Thermal expansion Rev.A data analysis method is presented that can be used to calculate kinetic rate constants for photoacid generation ͑Dill C values͒ in polymer and chemically amplified photoresist thin films using capacitance versus exposure dose data from resist coated interdigitated electrode ͑IDE͒ sensors. It is shown that the use of normalized IDE capacitance data can reduce or eliminate errors and variations in measured Dill C values obtained from our previous analysis method that are created by environmental factors such as humidity fluctuations and IDE factors such as variations in electrode geometry and size. Using this normalization method, the Dill C rate constants for 248 nm exposure of triphenylsulfonium triflate ͑TPS-Tf͒, triphenylsulfonium perfluoro-1-butanesulfonate ͑TPS-Nf͒, bis͑4-tert-butylphenyl͒iodonium triflate ͑TBI-Tf͒, and bis͑4-tert-butylphenyl͒iodonium perfluoro-1-butanesulfonate ͑TBI-Nf͒ in poly͑p-hydroxystyrene͒ ͑PHOST͒ were found to be 0.046, 0.040, 0.055, and 0.056 cm 2 /mJ, respectively. These results are shown to compare well with values obtained for these same systems using our original IDE data analysis method ͑0.045 cm 2 /mJ for TPS-Tf/PHOST, 0.039 cm 2 /mJ for TPS-Nf/PHOST, 0.056 cm 2 /mJ for TBI-Tf/PHOST, and 0.054 cm 2 /mJ for TBI-Nf/PHOST͒. The normalization method has a significant advantage in that it permits the determination of a Dill C parameter for a particular polymer-photoacid generator system using a single resist film coated IDE and a single exposure experiment.

Nonionic photoacid generator behavior under high-energy exposure sources

“…This experimental Dill C parameter for TAS-SbF 6 is consistent with previous literature results for triarylsulfonium PAGs in the range of 0.025 to 0.05 cm 2 / mJ. 21 This result reaffirms why ionic PAGs are the primary type of PAG used in DUV resist formulations. Such onium salt PAGs are generally the most efficient PAG family for generating acid using DUV exposures.…”

Copolymer fraction effect on acid catalyzed deprotection reaction kinetics in model 193 nm photoresists

“…11 An alternative approach is to assume that the system is homogeneous, i.e. the gradient of acid concentration is zero, but the photoacid can be effectively trapped by MAA, implying the diffusion coefficient becomes very small in MAA-rich regions as shown in Equation 3. This assumption is verified as will be discussed in greater detail.…”

“…Extensive efforts have been put on understanding the mechanism and kinetics of photoresist reactions in recent years. However, most studies have focused on the physico-chemical properties of the photoacid such as the photolysis efficiency [3][4][5][6][7][8][9] , the diffusivity 10-13 and the dissociation or acidity 14 in polymer photoresists. Fewer studies have focused on the effect of polymer photoresist and the reaction products on the reaction kinetics.…”

Pattern Transfer Characterization after Double-Level Lithography for a Fabrication of the Three-Dimensional Aluminum Titanium Carbide Air Bearing Surface of the Hard Disk Slider

“…1. Our previous works employed a lithography simulator, an increasingly popular tool for modeling and predicting lithography processes [24][25][26][27] due to its low cost and time consuming, to study the effect of the double-exposure to the lithographic parameters 28) including photoresist Dill's para-meters [29][30][31][32] and development parameters, the model extraction for double-exposure simulation, 33) and the adjustment of the simulation parameters to obtain an accurate prediction for double-exposure. 34) The key focus of this research is to investigate pattern transfer characteristics from the initial PR film structure, which is formed using a double-exposure process and validated modeled PR parameters determined previously, 28,33,34) to the AlTiC substrate by reactive ion etching (RIE) using fluorocarbon-based plasmas.…”