KR19980033980A - Method of calculating surface area of hemispheres formed on semiconductor poly-phase using AFM - Google Patents

Abstract

The present invention relates to a method of calculating the surface area of a hemisphere formed on a semiconductor poly-phase using an AFM capable of calculating the surface area of a hemisphere formed on a poly for forming a capacitor.

The present invention relates to a method of determining the lengths of a first line and a second line corresponding to two heights by an AFM using the first and second equations,

ℓ _β = (Formula 1)

ℓ _{β + 1} = (Second formula)

Obtaining a surface area of the hemisphere by using the length of the first line and the length of the second line according to the following equation 3,

A _H = (? _Beta +? _{Beta + 1} ) / 2 x? Y (third equation)

.

Therefore, there is an effect that the surface area of the hemisphere formed on the semiconductor poly-phase can be easily calculated using the AFM.

Description

Method of calculating surface area of hemispheres formed on semiconductor poly-phase using AFM

The present invention relates to a method of calculating a surface area of a hemisphere formed on a semiconductor poly-phase using AFM (Atomic Force Microscopy), and more particularly, to a method of calculating a surface area of a hemisphere formed on a poly- To a method of calculating the surface area of a hemisphere formed on a semiconductor poly-phase.

Recently, with the progress of semiconductor technology, miniaturization and high integration of DRAM are proceeding rapidly. The biggest problem in the high integration of the DRAM is how to keep the capacitance of the capacitor small while reducing the area of the memory cell.

On the other hand, the capacitance of the capacitor is proportional to the dielectric constant and the contact area of the dielectric film, and inversely proportional to the thickness of the dielectric film. Therefore, in order to increase the capacity of the capacitor, it is necessary to reduce the thickness of the dielectric film or to use an insulating film having a large dielectric constant or to increase the area. However, in order to increase the capacity of the capacitor as described above, it is not preferable to thin the insulating film in terms of the reliability of the semiconductor device.

Therefore, it is desirable to increase the effective cross-sectional area of the capacitor in order to increase the capacitance of the capacitor. As described above, a method of increasing the effective cross-sectional area of the capacitor has been studied and many methods have been proposed.

That is, a trench type capacitor which forms a capacitor having a storage electrode in a trench etched on a semiconductor substrate by variously deforming the shape of the S-poly which is a lower electrode of the capacitor, or a stacked capacitor structure which forms a stacked structure A method of using the same has been proposed.

However, as the method of changing the shape of the S-poly reaches a certain limit, a HSG (Hemi Spherical Growing) process technology capable of increasing the capacitance of the capacitor without changing the basic shape has been introduced.

The HSG process technology increases the surface area of the conventional capacitor by 1.6 times as the Spherical is formed by sputtering a nucleus of a specific atom on the S-poly top and growing poly around the nucleus. It is a technology that can be.

In such a case, there is a method of using a transparent mesh mesh (MESH) as a method of measuring the surface area.

The method of using the mesh is as follows. First, a hemisphere formed on a poly-phase is scanned by using Scanning Electron Microscopy (SEM). Then, an operator superimposes a mesh on the scanned image to form an image of the hemisphere on the mesh, .

However, the conventional method using the mesh has a problem that the surface area of the hemisphere can not be accurately calculated.

An object of the present invention is to provide a method of calculating the surface area of hemispheres formed on a semiconductor poly-phase using an AFM capable of calculating the hemispherical surface area more accurately than a conventional method using a MESH by calculating the hemispherical surface area using data obtained using AFM .

FIG. 1 is a graph showing a plurality of points formed on a surface of a hemispherical plane to explain a method of calculating a hemispherical surface area formed on a semiconductor poly-phase using the AFM according to the present invention.

FIG. 2 is a graph showing a three-dimensional view of a plurality of points formed on the surface of a hemisphere to explain a method of calculating a hemispherical surface area formed on a semiconductor poly-phase using the AFM according to the present invention.

According to an aspect of the present invention, there is provided a method of calculating a hemispherical surface area formed on a semiconductor poly-phase, comprising: obtaining the lengths of first and second lines corresponding to two heights by an AFM using first and second equations;

ℓ _β = (Formula 1)

ℓ _{β + 1} = (Second formula)

Calculating a surface area of the hemisphere by the following equation (3) using the lengths of the first line and the second line;

A _H = (? _Beta +? _{Beta + 1} ) / 2 x? Y (third equation)

.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a graph showing a plurality of points formed on a surface of a hemispherical plane to explain a method of calculating a hemispherical surface area formed on a semiconductor poly-phase using the AFM according to the present invention, and FIG. 2 is a graph 3 is a graph showing a plurality of points formed in the surface of a hemisphere in three dimensions to describe a method of calculating the surface area of the hemisphere formed on the polyphase.

Referring to FIG. 1, a plurality of points are formed on the surface of the hemisphere with distances of? X and? Y distances in the X and Y axis directions, respectively.

If the number of selected points in the X and Y directions is N _x and N _y , the number of points scanned by the AFM is N _x N _y .

Further, if the surface is a flat surface, ideally, it has a surface area of (N _x x DELTA X _x ) x (N _y x DELTA X _y ). This is denoted by A _i .

Actually, in HSG, it is required that hemispherical crystals are gathered rather than a flat surface, and let A _H be the surface area at this time.

Therefore, since the capacitance C of the capacitor increases in proportion to the value of A _H , it is needless to say that A _H / A _i requires a large value.

Therefore, assuming that the dielectric constant, the thickness, the doping amount of both electrodes, and the like of the capacitor dielectric are the same, it is possible to deduce the capacity of the capacitor by accurately obtaining A _H.

Referring to FIG. 2, a method for calculating A _H will be described. First, when measuring the height of the surface at each point from the left to the right with AFM, the lengths of the β th and β + 1 th lines are ℓ _{β and} ℓ _{β + 1} If N _x is sufficiently large, we can calculate as follows.

I.e., _β = ℓ . ≪ / RTI >

Similarly, ℓ _{β + 1} can also be obtained.

That is, ℓ _{β + 1} =

Therefore, A _H = (? _Beta +? _{Beta + 1} ) / 2 x (? Y).

Therefore, according to the present invention, it is possible to easily calculate the surface area of a hemisphere formed on a semiconductor poly-phase by using an AFM.

While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (1)

Obtaining the lengths of the first line and the second line corresponding to two heights by the AFM; ℓ _β = (Formula 1) ℓ _{β + 1} = (Second formula) Calculating a surface area of the hemisphere by the following equation (3) using the lengths of the first line and the second line; A _H = (? _Beta +? _{Beta + 1} ) / 2 x? Y (third equation) Wherein the surface area of the semi-spherical poly-phase is measured using an AFM.