Thermal Analysis

Dollimore, D.

doi:10.1021/a1960006p

Cited by 50 publications

(14 citation statements)

References 293 publications

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“…There are several methods for determining the kinetics of a reaction with DTA. [11][12][13][14] For ultrathin films, the most suitable method is based on determining the maximum reaction rate, which is the temperature at the maximum rate of heat absorption, or T max . The method works best for ultrathin films because it is not dependent on the onset of the reaction in the film, 11,15 only the peak reaction rate.…”

Section: Resultsmentioning

confidence: 99%

Scaling of Tg and reaction rate with film thickness in photoresist: A thermal probe study

Fryer

Nealey

Pablo

2000

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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A thermal probe technique, local thermal analysis, was used to measure the glass transition temperature (T g ) and reaction rate as a function of film thickness in chemically amplified photoresists. Using this technique, heat loss into a resist film was monitored as the temperature of the probe was ramped from ambient to temperatures as high as 200°C. The thermal events, glass transition temperature or heat evolved during reaction, were recorded as a function of the probe temperature. The T g of the photoresists UVN 30, UV6, UV3, KRS, and KRS-XE was measured for thick films and for ultrathin films approximately 50 nm thick. The measured T g in ultrathin resist films was 4-22°C higher relative to that measured in thick films. We also investigated the behavior of polyhydroxystyrene films, and found that crosslinking to the substrate can increase T g by a large amount. The photoresist films were then exposed with x-ray radiation at the same dose ͑950 mJ/cm 2 ͒ for both thick and ultrathin films to ensure a constant photogenerated acid concentration with thickness. The exposed areas of the films were heated with the thermal probe, and an increase in heat flow into the exposure area, attributed to the heat of reaction, prior to the glass transition temperature was measured. Kinetic rate constants were estimated with data from the power supplied to the probe as a function of temperature using a first order reaction model. The results indicate that the rate of reaction in ultrathin resist films is smaller than in thicker films for resists processed at the same postexposure bake temperature. We find that T g and reaction rate depend on film thickness in ultrathin photoresist films; the differences in these properties are expected to lead to large changes in the processing conditions used for ultrathin films relative to thick films.

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Section: Resultsmentioning

confidence: 99%

Scaling of Tg and reaction rate with film thickness in photoresist: A thermal probe study

Fryer

Nealey

Pablo

2000

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…DSC analysis offers a direct method of studying the thermal properties of various materials (20). It is the most widely used of all thermoanalytical techniques with applicability to polymers, pharmaceuticals, fats, oils, and various inorganic materials (21). It provides unique energy profile information, which specifically measures the temperatures and heat flows associated with material transitions as a function of time and temperature.…”

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confidence: 99%

Quantitative differential scanning calorimetric analysis for determining total polar compounds in heated oils

Tan

Man

1999

J Americ Oil Chem Soc

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A new differential scanning calorimetry (DSC) method was developed for the determination of total polar compounds (TPC) in heated oils. Three different types of edible oils, refined, bleached, and deodorized corn oil (CO), palm olein (RBDPO), and soybean oil (SO), were used in this study. Each type of edible oil was heated at 180°C in a deep fryer to obtain a range of TPC concentrations. In this study, the cooling thermograms of oil samples at a scanning rate of 1°C/min from −30 to −85°C showed a well-defined single crystallization peak. The study found that six DSC parameters, namely, peak temperature (PT), enthalpy (EN), onset (ON) and offset (OF) temperatures, peak height (HT), and the range of temperatures (RT) (the difference between onset and offset temperature) of this single crystallization peak could predict well the TPC of heated oils by using stepwise multiple linear regression analysis. These six parameters were used as independent variables while values from standard method were used as dependent variables. The coefficient of determination (R 2 ) of calibration models for CO, RBDPO, and SO were 0.9996, 0.9709, and 0.9980, respectively. Calibration models were validated with an independent set of samples. The R 2 of validation models were 0.9995, 0.9559, and 0.9961, respectively. Based on the results obtained, DSC appears to be useful instrumental method in determining the TPC of edible oils, and it may have the potential to replace the time-and chemical-consuming standard method.

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“…Par (23) to underline that the main calculation required is for the evaluation of the derivative of the kinetic profi le. The ratio of the derivative on λ − λ ∞ , that is, the profi le minus its value at the end of the reaction, gives at each point the value of k obs .…”

Section: Software For Processing Experimental Datamentioning

confidence: 99%

Alternative Accelerated Methods for Studying Drug Stability: Variable‐Parameter Kinetics

Alibrandi

2010

Pharmaceutical Sciences Encyclopedia

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Thermal Analysis

Cited by 50 publications

References 293 publications

Scaling of Tg and reaction rate with film thickness in photoresist: A thermal probe study

Scaling of Tg and reaction rate with film thickness in photoresist: A thermal probe study

Quantitative differential scanning calorimetric analysis for determining total polar compounds in heated oils

Alternative Accelerated Methods for Studying Drug Stability: Variable‐Parameter Kinetics

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