Patent ID: 7585421
Filing Date: 2009-09-08
Classification: B01D,G03F,Y10T

Abstract:
1. A method of fabricating a filter having calibrated through pores, the method comprising the following operations: A) using a continuous sheet having thickness of 5 μm to a few tens of micrometers, suitable for being etched by a lithographic operation; B) making a mask on a face of the sheet, the mask presenting etching selectivity S of at least 5, where etching selectivity S is defined as the ratio of the speed VF at which the material of the sheet is etched to the speed VM at which the material of the mask is etched; C) depositing a layer of photosensitive resin on the mask; D) making through holes in the layer of resin by photolithography, matching the configuration of pores to be made; E) etching through the mask via the pores in the layer of resin; and F) anisotropically etching through the sheet from the pores in the mask in order to make through pores in the sheet having an aspect ratio greater than 5, where aspect ratio is defined as the ratio of the depth of the pores to their diameter, the above-mentioned operations being performed in succession during sequential travel of the sheet.