Method of filling groove structure with tungsten

Abstract

The invention discloses a method of filling a groove structure with tungsten, which comprises the following steps: S1, forming a first groove in a first dielectric layer; S2, forming a first barrier layer; S3, carrying out a first tungsten deposition and chemical mechanical grinding process to form a first tungsten layer; S4, forming a second dielectric layer; S5, forming a second groove superimposed directly above the first groove; S6, forming a second barrier layer; S7, removing the second barrier layer from the bottom surface of the second groove and the outer surface of the second groove;and S8, carrying out second tungsten deposition from bottom to top to form a second tungsten layer. By using the method of the invention, seamless filling of tungsten can be realized, and the qualityof a tungsten-filled groove structure can be improved.

Description

technical field [0001] The invention relates to a method for manufacturing a semiconductor integrated circuit, in particular to a method for filling a groove structure with tungsten. Background technique [0002] In semiconductor integrated circuits, contact holes and through holes are usually implemented using tungsten plugs, which are tungsten metal structures formed by filling grooves with tungsten. In the existing process, the method of filling the groove structure with tungsten is to first form the corresponding groove in the corresponding dielectric layer at one time, and the depth of the groove is consistent with the depth of the required contact hole or via hole; after that, A barrier layer is formed on the inner surface of the groove, and then tungsten is deposited in the groove to fill the groove. However, in the existing method, tungsten deposition is a kind of conformal deposition growth (conformal growth) that will grow from both the side and bottom surfaces of...

AI Technical Summary

Problems solved by technology

However, in the existing method, tungsten deposition is a kind of conformal deposition growth (conformal growth) that will grow from both the side and bottom surfaces of the groove, that is, the deposition will follow the surface shape of the groove, because in the groove Tungsten growth will also occur on the side of the groove, which is very detrimental to filling the groove, because the tungsten grown from the side is easy to close at the top of the groove first, thus forming a gap inside the groove

Such gaps are easily exposed during the subsequent chemical mechanical polishing (CMP) of tungsten to form voids, which ultimately affect the performance of the tungsten metal structure.

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