KR19990000069A - Metal contact 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 metal contact of a semiconductor device, wherein an insulating film including a Pt storage electrode and a TiN diffusion barrier layer having a laminated structure is formed on a predetermined substructure, and the first contact hole is etched until the semiconductor substrate is exposed. Next, the Ti / TiN film and the W film were sequentially formed on the entire surface, etched back with SF ₆ plasma, etched back with Cl ₂ / BCl ₃ plasma, and then etched until the Pt film was exposed. The present invention relates to a technique for improving the electrical characteristics of a semiconductor device by forming a contact hole, performing a cleaning process using an organic solvent (for example, ACT) on the entire surface, and then forming and patterning a Ti / TiN film and a metal wiring.

Description

Metal contact manufacturing method of semiconductor device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a metal contact of a semiconductor device. In particular, a technique capable of fundamentally preventing contamination in a wet cleaning process by forming a tungsten metal plug after forming a medium speed contact hole and using it as a diffusion preventing film of metal ions. It is about.

As the contact hole itself connecting the upper and lower conductive wirings in the semiconductor device is reduced in size and the distance between the peripheral wirings, an aspect ratio, which is a ratio of the diameter and the depth of the contact hole, increases.

Therefore, in a highly integrated semiconductor device having multiple conductive wirings, accurate and tight alignment between masks in a manufacturing process is required to form a contact, thereby reducing process margin.

1 is a cross-sectional view of a metal contact process of a semiconductor device according to the prior art.

First, an insulating film 4 having a Pt film 2 as a storage electrode having a laminated structure and a TiN film 3 as a diffusion barrier film is formed on the semiconductor substrate 1.

Next, using the contact mask, the semiconductor substrate 1 is etched until the semiconductor substrate 1 is exposed to form the contact hole 5.

At this time, when the contact hole 5 is formed, the TiN film 3 as the diffusion barrier layer is etched to expose the Pt film 2 as the storage electrode at the same time.

According to the prior art as described above, when forming a subsequent metal contact when using a Pt film as a storage electrode in FeRAM and 1 giga DRAM or more, the lower material is exposed to the metal film of silicon and TiN / Pt at the same time during the wet cleaning process of the metal film Metal ions move from the bottom through the cleaning solution, causing serious contamination of the silicon junction, thereby deteriorating the electrical characteristics of the device.

Accordingly, the present invention is to solve the above problems to form an insulating film having a Pt storage electrode and a TiN diffusion barrier layer of a laminated structure and to form a first contact hole by etching until the semiconductor substrate is exposed, then the entire surface Ti / TiN and W films were sequentially formed on the substrate, etched back with SF ₆ plasma, etched back with Cl ₂ / BCl ₃ plasma, and then etched until the Pt film was exposed to form a second contact hole. After the post-treatment using an organic solvent, the metal ion is transferred from the Pt / TiN film through the post-treatment solution and bonded to the silicon substrate when the wet post-treatment is performed by forming and patterning the Ti / TiN film and the metal wiring. It is an object of the present invention to provide a method for manufacturing a metal contact of a semiconductor device to improve the electrical properties of the semiconductor device to prevent the phenomenon of contamination.

1 is a cross-sectional view of a metal contact process of a semiconductor device according to the prior art.

2a to 2e is a metal contact manufacturing process of the semiconductor device according to the present invention.

* Description of the symbols for the main parts of the drawings *

1,11: semiconductor substrate 2,13: Pt film

3,15: TiN film 4,17: insulating film

5, 19: contact hole 21, 27: Ti / TiN film

23: W film 25: 2nd contact hole

29: metal wiring

Metal contact manufacturing method of a semiconductor device in the present invention to achieve the above object

Forming a Pt film and a TiN film having a laminated structure in a predetermined substructure;

Forming an insulating film on the entire surface of the structure;

Forming a first contact hole by using a first contact mask on one side of the insulating layer until the semiconductor substrate of a predetermined portion of the insulating film is exposed;

Sequentially forming a Ti / TiN film and a W film on the entire surface of the structure;

Etching the W film / Ti / TiN film with SF ₆ plasma and then again back to Cl ₂ / BCl ₃ plasma;

Forming a second contact hole by etching a second contact mask on the other side of the insulating layer until the Pt film is exposed;

Performing a cleaning step using an organic solvent on the entire surface of the structure to remove metal ions;

And forming a Ti / TiN film and a metal wiring on the entire surface of the structure, followed by patterning.

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

2A to 2E are diagrams illustrating a metal contact manufacturing process of a semiconductor device according to the present invention.

First, a lower structure film (not shown) is formed on the semiconductor substrate 11, and a Pt film 13 and a diffusion barrier TiN film 15, which are storage electrodes having a stacked structure, are formed, and then a predetermined thickness is formed on the entire surface. The insulating film 17 is formed.

Next, the first contact hole 19 is formed on one side of the insulating layer 17 by using the first contact mask until the semiconductor substrate 11 of the predetermined portion is exposed as a contact (see FIG. 2A).

Next, a contact plug is formed by sequentially forming a Ti / TiN film 21 and a W film 23 serving as a conductive layer on the entire surface of the structure.

In this case, the Ti / TiN film 21 is formed to a thickness of 500 ~ 600Å by the sputtering method, the W film 23 is formed to a thickness of 4000 ~ 8000Å by chemical vapor deposition (chemical vapor deposition) (Fig. 2b).

Next, the W film / Ti / TiN films 23 and 21 are etched back with SF ₆ , SF ₆ / N ₂ , SF ₆ / O ₂ , SF ₆ / Ar plasma, and then Cl ₂ again. The remaining pimmers remaining on the insulating layer 17 are removed by etching back into / BCl ₂ plasma.

At this time, the etch back is performed, but the W film / Ti / TiN films 23 and 21 of the contact plug are etched to a thickness of 1000 to 2000 Å (see FIG. 2C).

Next, the second contact hole 25 is etched using the second contact mask until the Pt layer 13 formed on the other side of the insulating layer 17 is exposed.

Next, a wet cleaning process is performed on the entire surface of the structure using an organic solvent such as an ACT solvent.

At this time, the first contact hole 19 prevents the semiconductor substrate from being damaged due to the collective leakage current due to the diffusion of metal ions due to the contact plug of the W film 23 (see FIG. 2D).

Next, a Ti / TiN film 27 is formed on the entire surface of the structure, a metal wiring 29 made of Al is formed, and then patterned to complete the manufacturing process of the present invention (see FIG. 2E).

As described above, according to the present invention, by forming a tungsten metal plug after forming a dependent contact hole and using a diffusion barrier of metal ions, it is possible to fundamentally prevent electrical characteristics of a semiconductor device which prevents contamination accompanying post-wet processing. There is an advantage to improve.

Claims (8)

Forming a Pt film and a TiN film having a laminated structure in a predetermined substructure; Forming an insulating film on the entire surface of the structure; Forming a first contact hole by using a first contact mask on one side of the insulating layer until the semiconductor substrate of a predetermined portion of the insulating film is exposed; Sequentially forming a Ti / TiN film and a W film on the entire surface of the structure; Etching the W film / Ti / TiN film with SF ₆ plasma and then again back to Cl ₂ / BCl ₃ plasma; Forming a second contact hole by etching a second contact mask on the other side of the insulating layer until the Pt film is exposed; Performing a cleaning step using an organic solvent on the entire surface of the structure to remove metal ions; And forming a Ti / TiN film and a metal wiring on the entire surface of the structure, and then patterning the metal contact. The method of claim 1, wherein the Ti / TiN film is formed to a thickness of 500 to 600 GHz. The method of claim 2, wherein the Ti / TiN film is formed by a sputtering method. The method of claim 1, wherein the W film is formed to a thickness of 4000 ~ 8000 Å. The method of claim 4, wherein the W film is formed by a CVD method. In the _{SF 6 SF 6 / N 2,} SF 6 / O 2, metal contact method of producing a semiconductor device characterized by using a SF ₆ / Ar plasma in the plasma instead of to claim 1. 7. The method of claim 6, wherein the etching process is etched to a thickness of 1000 ~ 2000Å when the etch back. The method of claim 1, wherein the organic contact is used as an ACT solvent as the organic solvent.