Abstract: In order to determine the dielectric constant of a layer deposited on a semiconductor wafer (2), the density of the layer is obtained. To obtain that density, the wafer (2) without the layer is weighed in a weighing chamber (4) in which a weighing pan (7) supports the wafer on a weighing balance. The weight of the wafer is determined taking into account the buoyancy exerted by the air on the wafer (2). Then the layer is deposited on the wafer (2) and the weighing operation repeated. Alternatively a reference wafer may be used. If the material of the layer is known, the weight of the layer can be used to derive its density using a thickness measurement. Alternatively, if the density is known, the thickness can be obtained.

Abstract: A dispersant composition comprising the product of an amine, an alcohol, or an amino alcohol, with a hydrocarbyl-substituted succinic anhydride component exhibits improved viscosity stability and reduced chlorine content, when the hydrocarbyl-substituted succinic anhydride component comprises: (a) 10 to 95 weight percent of a component prepared by reacting a polyisobutylene with maleic anhydride in the presence of chlorine; and (b) 5 to 90 weight percent of a component prepared by reacting a polyisobutylene with maleic anhydride in the substantial absence of chlorine.