Method for chemically and mechanically polishing metals

Abstract

The invention provides a method for chemically and mechanically polishing a metal. The method comprises a step of performing grinding on three grinding tables. While performing grinding on the third grinding table, the method comprises the following steps of: presetting first grinding time and second grinding time, and performing the first step of grinding on the third grinding table within the first grinding time, and performing the second step of grinding on the third grinding table within the second grinding time; grinding an oxide layer and a metal by employing a grinding fluid having a grinding selection ratio greater than 1 to the oxide layer and the metal; when the first predetermined grinding time expires, grinding the oxide layer and the metal by employing a grinding fluid havinga grinding selection not greater than 1 to the oxide layer and the metal; and when the second predetermined grinding time expires, enabling the metal to reach a predetermined thickness and keep as high as the oxide layer. The method greatly improves the planarization degree of the metal in the chemical mechanical polishing process.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a chemical mechanical grinding method for metal. Background technique [0002] At present, with the wide application of electronic devices, the manufacturing process of semiconductors has been developed rapidly. In the manufacturing process of semiconductors, a chemical mechanical polishing process (CMP) is involved. Copper is generally used for metal interconnection lines in the interconnection layer of the back-end process, so chemical mechanical polishing of copper is required. [0003] In the prior art, the grinding of the metal copper layer is mainly realized by three grinding tables, and each grinding table performs a grinding process respectively. The method of chemical mechanical grinding of metal copper will be described in detail below. [0004] figure 1 It is a schematic cross-sectional view of the first process of the chemical mechanical polishin...

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Problems solved by technology

That is to say, this method adopted in the third process is not enough to thoroughly solve the defects of metal copper in the grinding process, that is, it cannot be realized image 3 ideal structure in

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