Patent ID: 7056649

Claim:
A process for producing a microstructured tool insert for injection molding a part which is produced from a synthetic material, a metal or from a ceramic material, said process comprising: (a) providing a wafer having a front side and a rear side; (b) photo-lithographically masking the front side of the wafer with a first etching mask which corresponds to an arrangement of first microstructures, (c) micro-structuring the front side of the wafer by means of plasma etching to form said arrangement of first microstructures on the front side of the wafer, (d) removing the first etching mask from the front side of the wafer, (e) photo-lithographically masking the rear side of the wafer with a second etching mask which corresponds to an arrangement of second microstructures, which are to be in fluid connection with the first microstructures on the front side of the wafer, (f) microstructuring the rear side of the wafer by means of plasma etching to form said arrangement of second microstructures having cavities on the rear side of the wafer, and which cavities issue into the first microstructures on the front side of the wafer, said cavities having inclined side walls and a tapered cross section, the width of this cross section increasing with distance from the rear side of the wafer, (g) removing the second etching mask from the rear side of the wafer, (h) attaching the rear side of the wafer to a carrier substrate to form a master, (i) applying an electrically conductive thin layer to the microstructured front side of the wafer and to the carrier substrate surfaces which are accessible through the mentioned cavities, (j) electrochemically depositing a metal layer on the front side of the wafer and in the cavities which are present therein and are formed by the second microstructures, (k) making planar the outer surface of said deposited metal layer, and (k) separating said deposited metal layer from the master, wherein the separated metal layer can be used as a tool insert for injection molding a part.