Abstract: Manufacturing a semiconductor device involves forming (200) a sacrificial layer where a micro cavity is to be located, forming (210) a metal layer of thickness greater than 1 micron over the sacrificial layer, forming (220) a porous layer from the metal layer, the porous layer having pores of length greater than ten times their breadth, and having a breadth in the range 10 nm-500 nanometers. The pores can be created by anodising, electrodeposition or dealloying. Then the sacrificial layer can be removed (230) through the porous layer, to form the micro cavity, and pores can be sealed (240). Encapsulating MEMS devices with a porous layer can reduce costs by avoiding using photolithography for shaping the access holes since the sacrificial layer is removed through the porous membrane.

Abstract: Spray compositions and particularly anhydrous aerosol compositions containing particulate antiperspirant actives exhibit a tendency for nozzle blockage, impeding discharge of the contents when a polyol humectant, such as glycerol, is blended into its base composition. The problem is overcome or at least ameliorated by preparation of a base composition, suitable for employment in conjunction with a propellant, that contains a low molecular weight (liquid) polyethylene glycol (PEG) as humectant, and particularly a PEG of molecular weight 150 to 500.