Formation method of contact hole

Abstract

The invention provides a formation method of a contact hole, comprising the following steps: providing a semiconductor substrate which comprises a conducting layer, an etch stop layer on the conducting layer and an interlayer dielectric layer on the etch stop layer; carrying out primary etching on the interlayer dielectric layer so as to form through holes on the interlayer dielectric layer; and carrying out secondary etching on the etch stop layer so as to form through holes on the etch stop layer, wherein the etching gas for the secondary etching comprises CH2F2, O2, N2 and gas with the fluorine-to-carbon ratio higher than 2. The formation method of the contact hole reduces the damage to the conducting layer at the bottom part of the contact hole of the semiconductor substrate.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for forming a contact hole. Background technique [0002] The manufacture of semiconductor integrated circuits is an extremely complex process, the purpose of which is to reduce the various electronic components and circuits required for a specific circuit on a small-area wafer. Wherein, each component must be electrically connected by an appropriate interconnection wire, so as to exert the desired function. [0003] As the production of integrated circuits develops toward ultra-large-scale integrated circuits (ULSI), the internal circuit density is increasing. As the number of components contained in the chip continues to increase, the available space for surface wiring is actually reduced. The solution to this problem is to adopt a multi-layer metal wire design, and use a multi-layer connection in which a multi-layer insulating layer and a conducti...

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Problems solved by technology

[0009] However, after testing the contact holes formed by the above method, it was found that there is a problem of damage to the underlying conductive layer. Figure 5 It is a test map of the surface of the semiconductor substrate after the contact hole is formed by using the traditional contact hole forming method

like Figure 5 As shown, there are defects caused by damage in the conductive layer 105 at the bottom of the contact hole of the semiconductor substrate

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