Method for forming self-aligned metallic silicide

Abstract

The invention discloses a method for forming a self-aligned metallic silicide. The method comprises the following steps: providing a semiconductor substrate, wherein the semiconductor substrate comprises a first area and a second area, and the surface of the semiconductor substrate in the first area is at least provided with a silicon area; forming an isolation layer for covering the semiconductor substrate in the second area; removing a natural oxidation layer of the silicon area through radio-frequency sputtering; forming a metal layer for covering the silicon area and the isolation layer through radio-frequency sputtering; forming a protective layer on the surface of the metal layer through radio-frequency sputtering; carrying out annealing on the semiconductor substrate so as to form a metal silicide layer; and removing the protective layer and an unreacted metal layer. The method disclosed by the invention is high in efficiency and low in energy consumption.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for forming a self-aligned metal silicide. Background technique [0002] In semiconductor manufacturing technology, metal silicide is widely used in source / drain contacts and gate contacts to reduce contact resistance due to its low resistivity and good adhesion with other materials. Metals with high melting points react with silicon to form metal silicides, and metal silicides with low resistivity can be formed through one-step or multi-step annealing process. With the improvement of the semiconductor process level, especially at the technology node of 90nm and below, in order to obtain lower contact resistance, nickel and nickel alloys have become the main materials for forming metal silicides. [0003] A method for forming a salicide is disclosed in the published Chinese patent application No. 200780015617.9, in which nickel alloy is selected as the materia...

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Problems solved by technology

[0007] The inventors found that before the metal silicide layer formed in the prior art, the natural oxide layer on the surface of the first source electrode 120, the first drain electrode 130 and the gate electrode 112 was removed by chemical reagents, and the chemical reagent removed the natural oxide layer The step of layering will consume part of the isolation layer 180. For this reason, the thickness of the isolation layer 180 in the prior art is generally more than 2000 angstroms, but an excessively thick isolation layer 180 makes it difficult to control the size of the device, which cannot reduce the size of the device and increase the cost.

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