Patent ID: 7655075

Claim:
A method for producing a filter element that includes the following successive steps: 1) application of a membrane layer to a carrier substrate, 2) etching a membrane chamber on the side of the carrier substrate opposite to the membrane layer, so that a residual layer of the carrier substrate still remains, 3) generation of pores in the membrane layer by means of a lithographic and etching process in order to create a perforated membrane, 4) removal of the residual layer of the membrane chamber by etching in order to expose the membrane layer of the membrane chamber, and 5) subjecting the membrane to an additional treatment in order to increase its mechanical strength, which additional treatment consists of one or more the following: 5.1) formation of crystal nuclei in the membrane layer in step 1, 5.2) heating temperature treatment of a structure of carrier layer and membrane layer in order to increase the crystalline fraction in the membrane layer in step 1 and/or after step 4, 5.3) isostatic hot pressing of the structure of carrier layer and membrane layer to increase the crystalline fraction in the membrane layer prior to step 3 or after step 4, and 5.4) generation of an internal prestress in the membrane layer in step 1 or after step 4.