Preparing method for through-hole between metallic layers and filling method

Abstract

The invention discloses a method for preparing and filling via holes between metal layers, which comprises: after metal in an under layer is etched, a first layer of intermetallic dielectric medium for isolation is deposited and steps formed when the metal in the under layer is etched are covered; the intermetallic dielectric medium for isolation on the metal in the under layer is removed througha chemical-mechanical planarization process; then, a layer of aluminum is deposited; lithography is carried out by using a via hole mask and a negative photoresist so as to define a protective layer of a via hole pattern; afterward, the aluminum layer is etched to prepare aluminum plugs for filling the via holes; a second layer of intermetallic dielectric medium for isolation is deposited, and the steps formed by the aluminum plugs are covered; after that, the intermetallic dielectric medium for isolation on the aluminum plugs is removed by the chemical-mechanical planarization process. The method adopts the aluminum plugs to fill the via holes, thus greatly improving the electroconductibility between metals in the interconnection process and solving the problem that the aluminum plugs are difficult to be realized after the size of device is reduced in the original process at the same time. The method can be widely applied in the processes for preparing semiconductor devices.

Description

technical field [0001] The invention relates to a method for preparing and filling through holes between metal layers in semiconductor manufacturing. Background technique [0002] In the traditional semiconductor process, the tungsten plug process is used to fill the via holes for connection between the two metal layers. The purpose of using the tungsten plug process is mainly because the aluminum material used as the metal connection is usually prepared by the sputtering process. With the reduction of the size of the through hole, the sputtering process cannot sputter the aluminum with a small atomic weight to the The depth of the through hole leads to poor contact; and the tungsten material can be realized by the chemical vapor deposition process, the chemical vapor deposition process and even the atomic layer deposition process can meet the requirements of high aspect ratio, so the traditional process uses the tungsten plug process to fill A via for a metal connection be...

AI Technical Summary

Problems solved by technology

[0009] A defect of the above-mentioned tungsten plug through-hole process is: the conductivity of metal tungsten is not high, so the electromigration (EM) in the actual metal through-hole is poor, and it will also cause a large capacitance / resistance delay effect, and The difficulty of the through-hole filling process in the manufacture

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