KR19980060528A - Capacitor Manufacturing Method of Semiconductor Device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a capacitor of a semiconductor device, wherein a lower electrode of a capacitor is formed of Ru, a strontium oxide film (SrO) is formed thereon, and a strontium ruthenium oxide film (SrRuO ₃ ) is formed by heat treatment at a low temperature. The present invention relates to a technology for improving the yield and reliability of semiconductor devices by forming a dielectric film made of PZT and then forming a capacitor to stabilize the chemically and thermally to improve leakage current characteristics of the ferroelectric film.

Description

Capacitor Manufacturing Method of Semiconductor Device

The present invention relates to a method for manufacturing a capacitor of a semiconductor device, and more particularly, by forming a strontium oxide film on a storage electrode of a semiconductor substrate, followed by heat treatment to form a strontium ruthenium oxide film and PZT to form a dielectric film. The present invention relates to a technique for improving the yield and reliability of semiconductor devices by stabilizing chemically and thermally to improve leakage current characteristics of ferroelectric films.

In general, ferroelectrics, such as (Pb, Zr) TiO3 (hereinafter PZT), have dielectric constants ranging from hundreds to thousands at room temperature, and have two stable residual polarization states, which are thinned to nonvolatile memory devices. The application of furnace is realized.

In addition, when the ferroelectric thin film is used as a nonvolatile memory device, the direction of the polarization is controlled in the direction of the electric field applied to input the signal, and the digital signals 1 and 0 are stored by the remaining polarization direction when the electric field is removed. Is to use the principle.

As described above, ruthenium dioxide (RuO ₂ ) as a lower electrode of the ferroelectric thin film shows good characteristics with respect to the loss or fatigue of polarization switching of the ferroelectric thin film due to electrical cycling compared to other electrodes. Current characteristics are deteriorating.

That is, since the deposition of the ferroelectric thin film is performed at a high temperature (above 500 ° C) and in an oxygen atmosphere, ruthenium dioxide (RuO ₂ ) reacts with oxygen to oxidize to a toxic gas state of RuO ₄ or to ruthenium dioxide (RuO ₂ ) surface. There is a problem that the roughness and the PZT thin film appears as a secondary phase.

Accordingly, the present invention is to solve the above problems to form a strontium oxide film (SrO) on the storage electrode of the semiconductor substrate, heat treatment at a low temperature to form a strontium ruthenium oxide film (SrRuO ₃ ), The present invention provides a method for manufacturing a capacitor of a semiconductor device, which improves the yield and reliability of the semiconductor device by improving the leakage current characteristics of the ferroelectric film by forming a dielectric film forming Pb (Zr) TiO ₃ to form a capacitor, thereby chemically and thermally stabilizing. The purpose is.

1A to 1J are capacitor manufacturing process diagrams of a semiconductor device according to the present invention.

* Description of the symbols for the main couples in the drawings *

10: semiconductor substrate 12: insulating film

14: contact plug 16: first diffusion barrier

18: second diffusion barrier 20: first conductive layer

22: second conductive layer 24: first dielectric film

26: second dielectric film 18: third dielectric film

30: plate electrode

In order to achieve the above object, a method of manufacturing a capacitor of a semiconductor device according to the present invention includes forming an insulating film having a storage electrode contact hole on a semiconductor substrate, forming a contact plug filling the contact hole, and forming the contact hole. a diffusion preventing film pattern on the plug upper part and a step of forming a laminated structure of Ti / TiN, or Ta / TaN and Ru, and the step of forming a conductive layer pattern to the storage electrode wraps around the surface of the diffusion preventing film pattern as RuO _2, wherein And heat-treating the semiconductor substrate to form a dielectric film on the storage electrode, and forming a plate electrode on the dielectric film.

Hereinafter, a method of manufacturing a capacitor of a semiconductor device according to the present invention will be described in detail with reference to the accompanying drawings.

1A to 1J are capacitor manufacturing process diagrams of a semiconductor device according to the present invention.

First, an element isolation insulating film (not shown), a gate oxide film (not shown), a gate electrode (not shown), or a bit line (not shown) are formed on the semiconductor substrate 10 using an oxide film. (12) is formed.

Next, a contact hole is formed in a portion of the insulating layer 12 that is intended to be exposed as a contact portion by an etching process using a contact mask.

Next, a 500-3000 mm thick polycrystalline silicon film (not shown) is formed on the entire surface of the structure by chemical vapor deposition (CVD), and then the entire surface of the polycrystalline silicon film is etched to fill the contact hole. To form a contact plug 14 (see FIG. 1A).

Next, a first diffusion barrier 16 made of titanium (Ti) or tantalum (Ta) having a thickness of 100 to 1000 Å is formed on the entire surface of the structure (see FIG. 1B).

Next, a second diffusion barrier 18 including a titanium nitride layer TiN or a tantalum nitride layer TaN having a thickness of 200 to 2000 μs is formed on the first diffusion barrier layer 16 (see FIG. 1C).

Next, the second diffusion barrier layer 18 pattern and the first diffusion barrier layer 16 pattern are etched by an anisotropic etching process using an exposure mask until the upper surface of the insulating layer 12 is exposed. 1d).

Next, a first conductive layer 20 made of ruthenium (Ru) having a thickness of 100 to 1000 에 is formed on the entire surface of the structure (see FIG. 1E).

Next, the contact plug 14 and the diffusion barrier layers 16 and 18 are formed on the first conductive layer 20 by forming a second conductive layer 22 made of ruthenium dioxide (RuO ₂ ) having a thickness of 500 to 5000 Å. A storage electrode composed of a pattern and conductive layers 20 and 22 is formed (see FIG. 1F).

Next, a first dielectric film 24 made of a strontium oxide film (SrO) having a thickness of 100 to 500 kPa is formed on the entire surface of the structure below 500 ° C. (See FIG. 1G.)

Next, a second dielectric film 26 made of strontium ruthenium oxide film (SrRuO ₃ ) is formed by heat treating the first dielectric film 24.

Here, by forming the strontium ruthenium oxide film (SrRuO ₃ ) in the heat treatment process, the dielectric film 26 may be chemically and thermally stabilized to improve leakage current characteristics of the ferroelectric film (see FIG. 1H).

Next, a third dielectric film 28 made of PZT having a thickness of 1000 to 5000 Å is formed on the second dielectric film 26 by an epitaxial process (see FIG. 1I).

Subsequently, a plate electrode 30 made of ruthenium dioxide having a thickness of 500 to 2000 Å on the third dielectric layer 28 is formed by chemical vapor deposition to complete the capacitor manufacturing process according to the present invention.

As described above, in the method of manufacturing a capacitor of a semiconductor device according to the present invention, a dielectric film made of a strontium oxide film is formed on a storage electrode of a semiconductor substrate, and then heat treated to form a strontium ruthenium oxide film, thereby chemically and thermally stabilizing. By improving the leakage current characteristics of the ferroelectric film, there is an effect of improving the yield and reliability of the semiconductor device.

Claims (4)

Forming an insulating film having a storage electrode contact hole on the semiconductor substrate; Forming a contact plug filling the contact hole; Forming a diffusion barrier pattern on the contact plug in a stacked structure of Ti / TiN or Ta / TaN and Ru; Forming a conductive layer pattern of RuO ₂ , which becomes a storage electrode surrounding the surface of the diffusion barrier pattern, Heat treating the semiconductor substrate to form a dielectric film on the storage electrode; And forming a plate electrode on the dielectric film. The method of claim 1, wherein the dielectric layer is formed of SrO / SrRuO ₃ / PZT. The method of claim 2, wherein the SrO is formed to have a thickness of 100 μs to 500 μs. The method of claim 2, wherein the PZT is formed to have a thickness of 1000 ns to 5000 ns.