Method for filling copper into groove

Abstract

The invention discloses a method for filling copper into a groove. The method comprises the following steps: forming the groove; step two, forming a barrier layer; step three, forming a seed layer; and step four, filling copper into the groove by using an electrochemical electroplating technology and forming a copper main body layer with which the groove is completely filled; and the step four comprises the following sub steps: step 41, carrying out conformal deposition of copper by using first current to form a first layer of copper grown on the bottom surface and side surface of the groove uniformly; step 42, carrying out deposition in the copper transition stage of gradually reducing the current size into second current from first current to form a second layer of copper of which the thickness of the bottom surface of the groove is greater than that of the side surface of the groove; and step 43, carrying out bottom upward deposition on copper by using second current to form a thirdlayer of copper with which the groove is completed filled. According to the method, repair of seeds on the side surface and bottom surface of the groove and upward filling from the bottom can be taken into account in the copper electroplating process simultaneously, so that the capacity of filling copper into the groove is improved, and the hole problem of groove side surface is solved.

Description

technical field [0001] The invention relates to a method for manufacturing a semiconductor integrated circuit, in particular to a method for copper-filled grooves. Background technique [0002] As the size of metallic copper wires shrinks, the gapfill of electroplated copper becomes more challenging. More advanced electroplating copper additives can increase the process window (window) of Cu gapfill, and the optimization of electroplating copper process can further improve the gapfill capability. Generally, the high current of electroplating copper can reduce the ionization of the inhibitor and form a conformal deposition (conformal dep). The conformal dep will grow uniformly on the side and bottom surface of the groove at the same time, and it can repair the copper seed (seed) to a certain extent. role, making the seed layer (seed layer) more continuous. Copper electroplating with low current can form gapfill from bottom up to complete void free filling of grooves or thro...

AI Technical Summary

Problems solved by technology

[0017] In the existing method, what is applied in step 41 is a first current pulse. After the first current pulse is completed, it is directly switched to the second current. good deposition, the continuity of the copper formed on the side of the groove 102 cannot be guaranteed, making it possible to produce sidewall voids

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