KR100329614B1 - Capacitor Formation Method of Semiconductor Device - Google Patents

Abstract

The present invention relates to a method for forming a capacitor of a semiconductor device, wherein the surface of the lower electrode and the insulating layer are plasma-treated in a nitrogen atmosphere, and then copper is metal oxide chemical vapor deposition (MOCVD). By selectively depositing only on the copper, the copper is formed in an uneven shape to increase the surface area of the charge storage electrode, thereby increasing the capacitance, and since the copper is formed, a separate doping process is not required. to be.

Description

Capacitor Formation Method of Semiconductor Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a capacitor of a semiconductor device, and in particular, by forming a lower electrode as a conductive layer, and forming copper having a selective deposition characteristic on the lower electrode to have an uneven shape by MOCVD. A technique of increasing the capacitance of a capacitor by increasing it.

In general, as the high integration of semiconductor devices is increased to 1G DRAM or more, a fixed capacitance of a capacitor is required. In order to solve this problem, a method of using a material having a high dielectric constant of a capacitor, reducing the thickness of a dielectric film, or increasing the surface area of a lower charge storage electrode has emerged.

Although not shown, a method of forming a capacitor of a semiconductor device according to the related art is as follows.

First, a device isolation oxide film and a gate oxide film are formed on a semiconductor substrate, and a MOS field effect transistor including a gate electrode and a source / drain electrode and a bit line are formed to planarize the entire surface.

Next, an interlayer insulating film is formed on the entire surface, and a charge storage electrode contact hole is formed to expose a portion of the source / drain electrode, which is intended as a charge storage electrode contact, and is connected to the source / drain electrode through the contact hole. After the charge storage electrode contact plug is formed, a lower electrode connected to the charge storage electrode contact plug is formed.

Next, after forming meta-stable polysilicon (MPS) on the lower electrode, a dielectric film and an upper electrode are formed to form a capacitor. Here, the MPS is typically a material layer that can be formed only on the silicon film.

In the method of forming a capacitor of a semiconductor device according to the prior art as described above, after forming a lower electrode, an MPS having an irregular shape is formed to increase the surface area, but after forming the MPS, defects in surface area are formed. In order to eliminate, there is an inconvenience of performing an annealing process using hydrogen phosphine, and there is a problem that a defect occurs due to the annealing process.

The present invention is to solve the problems of the prior art, by forming a concave-convex shape of the copper having a selective deposition characteristic on the lower electrode to increase the surface area of the charge storage electrode to increase the capacitance and at the same time the semiconductor device to simplify the process It is an object of the present invention to provide a method for forming a capacitor.

1 and 2 are cross-sectional views showing a method of forming a capacitor of a semiconductor device according to the present invention.

<Explanation of Signs of Major Parts of Drawings>

10 semiconductor substrate 20 interlayer insulating film

30: lower electrode 40: copper

In order to achieve the above object, a method of forming a capacitor of a semiconductor device according to the present invention,

Forming a lower electrode on the semiconductor substrate;

Nitrogen plasma treatment of the surface of the lower electrode;

And selectively depositing copper only on the lower electrode to increase the surface area by forming irregularities on the surface of the lower electrode.

Hereinafter, with reference to the accompanying drawings will be described in detail.

1 and 2 are cross-sectional views illustrating a method of forming a capacitor of a semiconductor device according to the present invention.

First, a lower structure such as an isolation layer (not shown), a gate oxide (not shown), a gate electrode (not shown), a source / drain region (not shown), and a bit line (not shown) are formed on the semiconductor substrate 10. After the formation, an interlayer insulating film 20 is formed over the entire surface.

Next, a charge storage electrode contact hole is formed in the semiconductor substrate 10 to expose a predetermined portion of the charge storage electrode contact, and an insulating layer spacer (not shown) is formed on the sidewall of the charge storage electrode contact hole.

Next, a conductive layer filling the charge storage electrode contact hole is formed on the entire surface, and the lower electrode 30 is formed by etching the conductive layer using a mask for a lower electrode (not shown). In this case, the conductive layer is formed of silicon.

Next, an annealing process is performed on the surface of the lower electrode 30 in a nitrogen gas atmosphere at 750 to 1000 ° C., or is plasma treated with nitrogen gas. In the above process, copper may be selectively deposited only on the lower electrode 30 among the lower electrode 30 and the interlayer insulating layer 20, which are silicon exposed to the outside.

Then, copper 40 is formed on the lower electrode 30 by the MOCVD method at a temperature of 130 to 170 ℃. In this case, the copper 40 is grown in the form of polycrystalline silicon, and has a growth process in which small grains are aggregated by surface movement. Therefore, the surface of the charge storage electrode can be increased by being deposited in the shape of the irregularities of the bend only in the upper portion of the lower electrode 30. In addition, since the copper 40 has excellent conductivity, a doping process is not necessary. (See Fig. 2)

Thereafter, a dielectric film and an upper electrode are formed in a subsequent process to form a capacitor.

As described above, in the method of forming a capacitor of a semiconductor device according to the present invention, the surface of the lower electrode and the insulating layer are plasma-treated in a nitrogen atmosphere, and then copper is selectively deposited only on the surface of the lower electrode by MOCVD. It is formed in a concave-convex shape to increase the surface area of the charge storage electrode to increase the capacitance, and there is an advantage of simplifying the process because it does not require a separate doping process after forming the copper.

Claims (4)

Forming a lower electrode on the semiconductor substrate; Nitrogen plasma treatment of the surface of the lower electrode; Selectively depositing copper only on the lower electrode to form an uneven shape on the surface of the lower electrode to increase the surface area. The method of claim 1, The plasma processing process is a capacitor forming method of a semiconductor device, characterized in that instead of the annealing process in a nitrogen gas atmosphere. The method of claim 2, The annealing process is a capacitor forming method of a semiconductor device, characterized in that carried out at 750 ~ 1000 ℃. The method of claim 1, The copper is a method of forming a capacitor of the semiconductor device, characterized in that the selective deposition by the MOCVD method.