Method for depositing metallic nitride series thin film

Abstract

The present invention generally relates to a method for depositing a metallic nitride series thin film, typically a TiN-series thin film. The TiN-series thin film according to the present invention is formed by a CVD, and contains Ti, O and N to have a higher barrier characteristic than those of conventional TiN thin films, so that TiN-series thin film can suitably used as a barrier layer. In addition, a TiN-series thin film according to the present invention is formed by a CVD, and contains Ti, N and P to have a lower resistance than those of conventional TiN films, so that TiN-series thin film can suitably used as a barrier layer or a capacitor top electrode. Moreover, if a TiN-series thin film containing Ti, O, N and P is formed by a CVD, the TiN-series thin film can have both of a high barrier characteristic and a low resistance characteristic.

Description

CROSS REFERENCE TO RELATED APPLICATION [0001] This is a continuation-in-part application of patent application Ser. No. 09 / 660,546 filed on Sep. 12, 2000, now abandoned.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates generally to a method for depositing a metallic nitride series thin film, typically a TiN-series thin film, which is used as, e.g., a barrier layer, a capacitor top electrode, a gate electrode or a contact part, in a semiconductor device. [0004] 2. Description of the Related Art [0005] In the production of semiconductor devices, the construction of circuits tends to have a multilayer metallization structure on a recent demand for higher density and higher density integration. Therefore, an embedding technique for electrical connections between layers, such as a contact hole which is a connecting part between a bottom semiconductor device layer and a top wiring layer, and a via hole which is a connecting part between top ...

AI Technical Summary

Benefits of technology

[0016] It is therefore an object of the present invention to provide a method for depositing a high-quality metallic nitride series, typically TiN-series, thin film having a higher barrier characteristic and / or a lower resistance than those of a conventional TiN film formed by a CVD.

[0028] Moreover, in a semiconductor device, these TiN-series thin films are used as (1) a barrier layer or an embedded wiring portion in a contact part between a wiring layer and a semiconductor substrate or a conductive layer arranged thereon, (2) a top electrode layer, barrier layer or bottom electrode of a capacitor portion having an insulating layer of Ta2O5, RuO and so forth, (3) at least a part of a gate electrode, and (4) a contact structure on a major surface of a semiconductor substrate, so that it is possible to obtain excellent characteristics.

[0029] According to the present invention, it is possible to deposit such TiN-series thin films of high-quality by carrying out the pre-heating step and / or the pre-flowing step. Specifically, by carrying out the pre-heating step, it is possible to stabilize the temperature of the substrate before the later step of forming a thin film. By carrying out the pre-flowing step, it is possible to stabilize the flows of the TiCl4 gas, the O-containing gas and / or the PH3 gas before the next step of introducing those gases into the process vessel, i.e. the step of forming a thin film. In addition, by carrying out the pre-flowing step, it is possible to precisely control the flow rates of those gases in the next step of forming a thin film, even if the flow rates are very small. It is more effective to equalize the flow rates in the pre-flowing step with those in the next step of forming a thin film.

[0033] Thus, according to the present invention, it is possible to deposit such metallic nitride series thin films of high-quality by carrying out the pre-heating step and / or the pre-flowing step.

Problems solved by technology

In addition, when W or a W alloy is used as an embedded layer for a contact hole, WF6 gas used for forming the embedded layer tends to react with silicon of the substrate to deteriorate electrical characteristics to obtain undesired results.

Recently, the scale down and high density integration of devices are particularly required, and the design rule is particularly severe.

As a result, the embedding performance of the PVD film is bad, so that it is not possible to ensure a sufficient contact resistance.

However, such a high dielectric material is not more stable than SiO2 which has been conventionally used as a capacitor gate material.

Therefore, when a polysilicon, which has been conventionally used as a top electrode, is used, it is oxidized by heat history after the preparation of a capacitor, so that it is impossible to form a stable device.

However, a recent highly integrated capacitor type, which requires a high coverage, e.g., a crown type, a fin type, or a RUG polysilicon, which has irreguralities formed on a polysilicon layer in order to increase the capacity of a capacitor when the crown type or fin type is formed, can not be deposited as a top electrode.

If the specific resistance is so high, it is not possible to obtain sufficient characteristics when it is applied to a capacitor top electrode.

In particular, the low barrier characteristic causes problems when the TiN film is used as a barrier layer for a Cu (copper) wiring or when the TiN film is used as an oxygen diffusion barrier, on the occasion of forming a Ta2O5 capacitor top electrode.

That is, the corrosion of the Cu wiring due to the remaining chlorine and the decrease of the capacity of Ta2O5 due to the diffusion of O (oxygen), which increases the thickness of the Ta2O5 film, cause problems.

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