Resist processing controllable parameters

The process control of the post-exposure bake that is required for chemically amplified resist systems deserves special attention. Several considerations are apparent from the previous fundamental discussion. In addition for the need to understand the chemical reactions and kinetics of each step, it is important to account for the diffusion of the acid. Not only is the reaction rate of the acid-induced deprotection controlled by temperature but so is the diffusion distance and rate of diffusion of acid. An understanding of the chemistry and chemical kinetics leads one to predict that several process parameters associated with the PEB will need to be optimized if these materials are to be used in a submicron lithographic process. Specific important process parameters include ... 

To clarify the selection of a particular MLR system (ILR, 2LR, or 3LR system) a comparison in terms of process complexity, resolution, aspect ratio, linewidth tolerance, sensitivity and effort required for research and development will be given. Then a comparison between deep-UV and RIE PCM systems in terms of resolution, aspect ratio, substrate patterning processes allowed, temperature stability, resist removal at the alignment sites, tool-controlling parameters, and tool cost will be included. 

At Merck KGaA in Darmstadt (Germany), in-line UV spectroscopy has been used for monitoring a distillation setup for solvent purification." A transmission probe was implemented at the top of the column. Solarization-resistant UV fibers guided the light to a diode array spectrometer. From the spectra, a quality parameter was extracted and fed to the process control system (PCS). As an example, the quality parameter would exhibit a transient behavior upon column startup. Below a defined threshold value of the parameter, the PCS would assume sufficient product quality and switch the exit stream from waste to product collection. The operation of the spectrometer does not take place in a direct manner, but rather via the PCS. 

The methods can be classified by the controlled parameter (E or i) and by the quantities actually measured or the process carried out. Thus in controlled-potential techniques the potential of the working electrode is maintained constant with respect to a reference electrode. Since the potential of the working electrode controls the degree of completion of an electrolytic process in most cases, controlled-potential techniques are usually the most desirable for bulk electrolysis. However, these methods require potentiostats with large output current and voltage capabilities and they need stable reference electrodes, carefully placed to minimize uncompensated resistance effects. Placement of the auxiliary electrode to provide a fairly uniform current distribution across the surface of the working electrode is usually desirable, and the auxiliary electrode is often placed in a separate... 

Figure 11.49 Effect of electron-beam curing of resists based on poly(methacrylate) platform and hybrid methacrylate/alicyclic polymer platform on polygate etch. Electron-beam curing improves etch resistance by up to 50% relative to the control (uncured) sample. Processing was done in a nitrogen environment of the ElectronCure Electron Beam Process Chamber utilizing these electron-beam parameters 3.75 keV, 6 mA, 2000 pC/cm. The wafer temperature of the standard (Std.) process was not controlled, that for the electron-beam standard cure (ESC) process was kept at a medium temperature, that for the low-temperature (LT) process was maintained at a iow temperature, whiie that for the control was at room temperature. [After R. Dammel, Practical resist processing, SPIE Short Course No. SC616 (2005).]...

Wastewater alkalinity is also an important parameter in process control. It is a measure of the potential resistance of the digestion process to pH fluctuations. High alkalinity thus ensures process stability. Alkahnity concentrations in the range of 2000-5000mg/L as for CaCOj are typically required to maintain the pH at or near neutral (Metcalf Eddy, 2003 Polprasert, 1996). 

Obviously corrosion is an electrochemical process with current in the form of ions flowing through the concrete. The resistivity can tell us the capacity of the concrete to allow corrosion. It will not tell us if corrosion has started or if that capacity is being used to the full. Hence the statement above that at less than 10 kfJ cm resistivity is not the controlling parameter, but at more than 100 ki. cm you cannot distinguish between active and passive steel as the resistivity will effectively stop corrosion. 

When an extruder is working under steady-state conditions several factors can influence the process. The primary parameters that in principle can be controlled externally are the screw speed, the throughput, the barrel temperature, and the die resistance. All other parameters are influenced by the changes in the primary variables, e.g., filled length, heat transfer, and pressure gradient, or are predetermined, e.g., screw geometry or material properties. 

Abstract A short overview of relevant processes and parameters in spreading of liquids on substrates is presented. In a simplified view, the dynamics of these processes can be understood as being controlled by the balance of driving forces and resistance due to dissipative processes. Analogies between spreading and dewetting are discussed. 

The critical properties for optoelectronic materials are bandgap (operating range), carrier lifetime (efficiency), and resistivity (response time). To optimize these properties, it is necessary to have control of the process parameters such as ... 

All disinfection and sterilization processes for equipment should be validated, for preference using a microbiological challenge with an organism of appropriate resistance to the disinfectant, sterilant or sterilizing conditions. Once the required log reduction of the challenge organism has been achieved, physical and/or chemical parameters can be set which form the critical control points for the process. 

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