An equipment assembly for preparing, harvesting and collecting particles is disclosed. The assembly comprises a tandem filter system with one or more high pressure filters, one or more low pressure filters and one or more collection vessel. Particles can be prepared, harvested and collected continuously, semi-continuously or in a batch-type operation. A tandem filter system and its method of use are also disclosed. Particles made with the assembly and according the instant methods are also disclosed. The assembly provides improved particle harvesting and collection over other systems and permits continuous particle formation, in particular by dispersion of a solute-containing process fluid within a supercritical anti-solvent. An equipment assembly for preparing, harvesting and collecting particles is disclosed. The assembly comprises a tandem filter system with one or more high pressure filters, one or more low pressure filters and one or more collection vessel. Particles can be prepared, harvested and collected continuously, semi-continuously or in a batch-type operation. A tandem filter system and its method of use are also disclosed. Particles made with the assembly and according the instant methods are also disclosed. The assembly provides improved particle harvesting and collection over other systems and permits continuous particle formation, in particular by dispersion of a solute-containing process fluid within a supercritical anti-solvent. Described are apparatus and methods for processing a semiconductor wafer so that the wafer remains in place during processing. The wafer is subjected to a pressure differential between the top surface and bottom surface so that sufficient force prevents the wafer from moving during processing, the pressure differential generated by applying a decreased pressure to the back side of the wafer.Se da a conocer un ensamblaje del equipo para preparar, extraer y recolectar partículas. El ensamblaje comprende un sistema de filtros
