Abstract: A method includes providing a substrate having a surface such that a first hard mask layer is formed over the surface and a second hard mask layer is formed over the first hard mask layer, forming a first pattern in the second hard mask layer, where the first pattern includes a first mandrel oriented lengthwise in a first direction and a second mandrel oriented lengthwise in a second direction different from the first direction, and where the first mandrel has a top surface, a first sidewall, and a second sidewall opposite to the first sidewall, and depositing a material towards the first mandrel and the second mandrel such that a layer of the material is formed on the top surface and the first sidewall but not the second sidewall of the first mandrel.

Abstract: An apparatus and a method for determining concentration of fluorine ions in aqueous solutions are provided. In the apparatus, a pH sensor is provided for sensing a pH value of an aqueous solution to be determined. A pH controller is then used to compare the pH value determined with stored pH data to determine whether the aqueous solution is acidic or alkalinic. An acid dispenser or a base dispenser is then used to dispense either an acid or a base into the pH adjustment tank for adjusting the pH value of the aqueous solution to within a desirable range. For instance, for the detection of fluorine ions, a suitable pH range is between about 4 and about 10. After the pH value is stabilized in the aqueous solution, a fluorine ion sensor may be used to sense the fluorine ion concentration in the aqueous solution. A common acid and base which may be used to bring the pH value within the desirable range may be H2SO4 and NaOH.