Patent ID: 7498266
Filing Date: 2009-03-03
Classification: B81B,B81C,H01L

Abstract:
1. Method for structuring of silicon substrates for microsystem technological device elements, wherein the silicon substrate is covered with an etching mask and wherein the structures are furnished with a predetermined etching profile in the micrometer region with side walls and an etching depth At, wherein for the generation of a predetermined positive etching profile, the side walls of the structures are furnished with the defined slope angle β of from 60 degrees to 88 degrees relative to the etching bottom and the structures are generated with an etching depth At in the micrometer region, wherein a) initially an isotropic etching is performed such that a mask under etching u is generated, wherein the mask under etching u is formed approximately equal to the etching depth At, b) in the following the etching depth At is increased in an anisotropic etching in one process with alternatingly successively following etching and polymerization steps, such that the mask under etching u remains constant and such that the etching front of the etching profile obtains a new course, wherein the side walls of the structure are covered with a polymer, c) whereupon the polymer is removed at the side walls of the structure with an O2-plasma, and d) the isotropic etching of the step a), the anisotropic etching of the step b) and the removal of the polymer of the step c) are repeated as many times until the predetermined positive etching profile is obtained, e) wherein the slope angle beta is determined in a positive etching profile by adjustment of a time ratio Z according to the equation between the step of the isotropic etching according to step a) and the step of the anisotropic etching according to step b) is determined, wherein t isotropic represents the interval period of the isotropic etching step a) and wherein t anisotropic represents the interval period of the anisotropic etching step b).