Method for forming contact hole

Abstract

The invention discloses a method for forming a contact hole, which comprises the following steps of: sequentially forming an insulating medium layer, a hard mask layer and a photoresist layer on a semiconductor substrate; forming the graph of a contact hole opening on the photoresist layer; by taking the photoresist layer as a mask, etching the hard mask layer along the graph of the contact hole opening so as to form the contact hole opening; removing the photoresist layer; by taking the hard mask layer as the mask, etching the insulating medium layer to a certain depth along the contact holeopening by a plasma etching process, wherein the depth is one third to three fourths of the depth of a target contact hole; determining the type of charged ions accumulated on the surface of the hardmask layer, and introducing plasmas of which the type is opposite to that of the charged ions into a reaction chamber until the charged ions are neutralized; and by taking the hard mask layer as the mask, continuing to etch the insulating medium layer until the semiconductor substrate is exposed so as to form the target contact hole. The contact holes with uniform opening width can be formed by the method.

Description

technical field [0001] The invention relates to the field of manufacturing semiconductor devices, in particular to a method for forming a contact hole. Background technique [0002] With the rapid development of ULSI (Ultra Large Scale Integration), the manufacturing process of integrated circuits has become more and more complex and sophisticated. In order to improve the integration level and reduce the manufacturing cost, the key dimensions of the components are getting smaller and the number of components per unit area of ​​the chip is increasing. The vertical space further increases the integration density of the device. Metal material needs to be deposited in the contact holes between the wirings of each layer for electrical connection. [0003] As the critical dimension of the component becomes smaller, the critical dimension of the contact hole becomes smaller and smaller. At the same time, the depth of the contact hole becomes larger (the aspect ratio of the contac...

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