Method for making double-metal inlaid structure

Abstract

The invention discloses a method to fabricate a dual metal mosaic structure. A dielectric layer and a metal mask layer are sequentially developed on a substrate which is provided with a conductive layer and an underlayer; the substrate is patterned, and a window for the dielectric layer is formed, exposed outside the underlayer; then a packing layer is filled in the window of the dielectric layer, and the height of the packing layer is between one forth and a half of the depth of the window of the dielectric layer, then a groove is fashioned between the metal mask layer and the dielectric layer; after that, the packing layer is removed and the underlayer exposed outside the window of the dielectric layer is etched, with the metal mask layer as the mask; finally, metal layers are developedin the window of the dielectric layer and in the groove, and the metal mask layer is removed.

Description

technical field [0001] The invention relates to a method for manufacturing a metal interconnection, and in particular to a method for manufacturing a double metal damascene structure. Background technique [0002] With the improvement of the integration level of semiconductor devices, the use of multiple metal interconnections is becoming more and more extensive. Generally, the lower the resistance value of the metal layer of the multi-metal interconnection, the higher the reliability of the device and the better the performance. Among metal materials, copper metal has a low resistance value and is very suitable for multi-metal interconnection. However, because copper metal is difficult to pattern by traditional photolithography and etching technology, a process called dual damascene has been developed. [0003] The dual damascene process is a technique of forming trenches and openings of dielectric windows in the dielectric layer, and then backfilling metal to form metal w...

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Problems solved by technology

Please refer to Figure 1A-1B During the etching process of the trench 110, the liner layer 104 exposed by the dielectric layer window opening 108 will also be damaged by the etchant, so that the metal layer 102 is exposed, causing electrical problems in the device

In addition, during the etching process, the silicon nitride layer 107 and the underlying dielectric layer 106 are also easily damaged by the etchant, so that the top corner of the trench 110 is rounded.

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