Method for making thick metal inductance in integrated circuit

Abstract

The method includes steps: (1) using physical vapor deposition to deposit Ti, TiN, AlCu, and TiN in sequence to form thick metal films interlinked through top level; (2) using thick photoresist as metal graph protection layer in etching time to carry out photo etching for thick metal layers; (3) using Cl2 and BCl3 as main etching gases, the dry etching method carries out etching for thick metal layers; (4) using wet cleaning process to carry out cleaning step after etching. The invention is suitable to IC-manufacture area.

Description

technical field [0001] The invention relates to the field of manufacturing integrated circuits, in particular to a method for manufacturing thick metal inductors in integrated circuits. Background technique [0002] In radio frequency integrated circuits, it is necessary to use thick top-layer interconnection metals as inductive materials to make integrated circuit inductive components. However, the fabrication of thick metal inductors needs to overcome the following points in the prior art: first, the etching of the thick metal layer. In the existing 0.25um MOS integrated circuit, the thickness of the usual top layer metal film is about 8000 angstroms. Since it will also be used as an inductor, a thick metal film must be used in order to obtain low resistivity. The process gas, flow rate and time used for etching in the prior art Process parameters such as power and power will not be able to meet the etching requirements of thick metal layers; second, the wet cleaning proc...

AI Technical Summary

Problems solved by technology

In the existing 0.25um MOS integrated circuit, the thickness of the usual top layer metal film is about 8000 angstroms. Since it will also be used as an inductor, a thick metal film must be used in order to obtain low resistivity. The process gas, flow rate and time used for etching in the prior art Process parameters such as power and power will not be able to meet the etching requirements of thick metal layers; second, the wet cleaning process after etching

Due to the use of a thick metal film, the thickness of the corresponding photoresist must be thickened during etching, which leads to a large increase in the polymer produced during the etching process, which brings great difficulty to the subsequent cleaning steps. The choice of cleaning solution And a reasonable cleaning time is extremely important. Using the existing cleaning process may cause the polymer to be cleaned uncleanly, or excessive cleaning may cause the sidewall of the metal line to be corroded and form a cavity, which will affect the reliability of the interconnection and the performance of the inductance.

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