KR20000026696A - Lower electrodes of etching equipment - Google Patents

Abstract

PURPOSE: Lower electrodes of an etching equipment are provided to evenly cool a whole wafer, to smoothly supply a helium gas for cooling to edges of the wafer, to unify etching ratios in each part of the wafer, and to prevent a photoresist being burned, by obtaining a unified cooling effect on the whole wafer and by evenly distributing temperature, by having a plurality of helium pass lines of the lower electrodes. CONSTITUTION: Lower electrodes(310) of an etching equipment which are equipped on a chamber of the etching equipment, selectively etching a thin film deposited on a semiconductor wafer(10) by using plasma, and which the semiconductor wafer is mounted on the upper part thereof, comprises helium injecting holes(321), a plurality of helium pass lines, and helium connection lines(322). The helium injecting hole is formed to be pierced as upper/lower directions on predetermined parts of the lower electrodes, and supplies a helium gas for cooling the wafer to upper parts of the lower electrodes from outside. The plurality of helium pass lines are formed on concentric circles having different diameters on upper sides of the lower electrodes. The helium connection lines are formed on the upper sides of the lower electrodes to connect the helium injecting hole with the helium pass lines.

Description

Bottom electrode of etching equipment

The present invention relates to an etching apparatus used in the manufacturing process of a semiconductor device, and more particularly, to a lower electrode of a dry etching apparatus using plasma.

In general, a semiconductor device is subjected to various processes, among which a process of depositing a thin film on a semiconductor wafer and a process of selectively etching the deposited thin film are essential. The process of etching the thin film may be classified into a wet etching process and a dry etching process. The wet etching process is a process of etching a thin film using a chemical solution, whereas the dry etching process is mainly a process of etching a thin film using plasma. In particular, the wet etching process is not suitable for forming a fine pattern because isotropic etching is performed, whereas the dry etching process is suitable for manufacturing highly integrated semiconductor devices because anisotropic etching is possible.

An etching apparatus for performing a dry etching process using the above-described plasma includes a chamber for maintaining a predetermined vacuum state, a lower electrode installed in the chamber, and a lower electrode on which a semiconductor wafer is mounted, and an upper electrode installed on the lower electrode. . The lower electrode usually serves as a positive electrode, and the upper electrode normally serves as a negative electrode, and a plasma is formed between the lower electrode and the upper electrode. In addition, since the temperature of the wafer is increased during the dry etching process using plasma, the wafer cooling helium (He) gas is supplied to the lower electrode on which the wafer is mounted to realize a stable process by lowering the temperature of the wafer in progress. Means are provided.

1 is a plan view of a lower electrode of a conventional dry etching apparatus, and FIG. 2 is a cross-sectional view A-A of the lower electrode illustrated in FIG. 1.

As shown in FIGS. 1 and 2, the conventional lower electrode 110 has the same disk shape as the wafer 10, and the upper surface on which the wafer 10 is mounted has a substantially dome shape. . In addition, a helium inlet 121, a helium connection line 122, and a helium pass line for supplying helium (He) gas to the bottom surface of the wafer 10 to cool the wafer 10 to the lower electrode 110. 123 is provided.

The helium inlet 121 is for supplying cooling helium to the bottom surface of the wafer 10. The helium injection hole 121 penetrates the lower electrode 110 from the lower side to the upper side, and typically four are formed on the center of the lower electrode 110. have. The helium pass line 123 is formed along a circumference having a predetermined diameter on an upper surface of the lower electrode 110, and the helium connection line 122 connects the helium inlet 121 and the helium pass line 123. By connecting the two are formed on the upper surface of the lower electrode 110 to be perpendicular to each other.

Here, the size of the lower electrode 110 and the position of the helium pass line 123 may vary depending on the size of the wafer 10 to be mounted, but the lower electrode 110 for 8-inch wafer, which is currently mainstream, is used as an example. For example: The upper diameter D1 of the 8-inch wafer lower electrode 110 is 201.78 mm slightly larger than the diameter of the wafer 10, and the diameter D2 of the helium passline 123 is 152.4 mm.

However, in the case of the conventional lower electrode 110 having such a structure, since the helium pass line 123 and the helium connection line 122 are not provided at the edge portion of the wafer 10, the helium gas for cooling is provided at the portion. The supply of is not smooth. Therefore, the edge portion of the wafer 10 has a problem that the cooling effect is lower than that of the center portion of the wafer 10 and is higher than the temperature of other portions.

Due to such a problem, the etching rate of the upper portion and the edge portion of the wafer 10 is changed. This is because the line width (Critical Dimension: CD) and the uniformity are particularly important in the semiconductor device manufacturing process. A difference in the thickness of the remaining oxide film (R-TOX) is generated.

In addition, a phenomenon in which the photoresist pattern formed on the surface of the wafer burns due to a temperature increase without properly cooling the wafer edge portion. Accordingly, there is a problem in that it is difficult to completely remove the photoresist pattern after the etching process is completed, as well as the smooth etching process is not performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a lower electrode of an etching apparatus, in which a plurality of helium passlines are provided to cool the entire wafer more uniformly. .

1 is a perspective view showing a lower electrode of a conventional dry etching equipment;

2 is a cross-sectional view A-A of the lower electrode shown in FIG. 1;

3 is a perspective view showing a lower electrode of an etching apparatus according to the present invention;

4 is a sectional view taken along the line B-B of the lower electrode shown in FIG.

<Explanation of symbols for the main parts of the drawings>

10 Wafer 110,310 Lower electrode

121,321 ... Helium inlet 122,322 ... Helium connection line

123 Helium passline 323a Inner helium passline

323b ... outer helium passline

In order to achieve the above object, the lower electrode of the etching apparatus according to the present invention is installed in a chamber of an etching apparatus for selectively etching a thin film deposited on a semiconductor wafer using a plasma, on which a semiconductor wafer is mounted. In the lower electrode of the etching equipment; Helium injection holes are formed so as to penetrate in a predetermined portion of the lower electrode in the vertical direction and supply a cooling helium gas for cooling the wafer from the outside to the upper portion of the lower electrode, and have different diameters on the upper surface of the lower electrode. And a helium gas supply means for cooling the wafer including a plurality of helium pass lines formed on a concentric circle, and a helium connection line formed on an upper surface of the lower electrode to connect the helium injection hole and the helium pass line. It is done.

Here, the helium pass line is preferably provided with two of the outer helium pass line located on the outer portion of the lower electrode, and the inner helium pass line located on the center of the lower electrode.

In addition, the helium inlet may be formed in plural on the center of the lower electrode, and the helium connection line is preferably arranged radially so that the four cross each other.

Therefore, according to the lower electrode of the etching apparatus according to the present invention, the edge portion of the wafer can be cooled more effectively, so that the uniform etching is performed on the entire wafer.

Hereinafter, a preferred embodiment of the lower electrode of the etching equipment according to the present invention with reference to the accompanying drawings will be described in detail.

3 is a plan view of a lower electrode of the dry etching apparatus according to the present invention, Figure 4 is a cross-sectional view B-B of the lower electrode shown in FIG.

3 and 4 together, the lower electrode 310 of the etching apparatus according to the present invention is installed in the chamber of the etching apparatus for selectively etching the thin film deposited on the semiconductor wafer 10 using a plasma. And cooling helium gas supply means for cooling the semiconductor wafer 10 mounted thereon.

The lower electrode 310 has a wafer 10 mounted thereon, and has a disk shape having a predetermined thickness having an upper surface of a lower dome shape.

The cooling helium gas supply means serves to supply the cooling helium to the bottom surface of the wafer 10 in order to cool the wafer 10, the helium inlet 321, helium connection line 322 and helium And pass lines 323a and 323b.

The helium injection hole 321 is formed to penetrate the lower electrode 310 in the vertical direction, and serves to supply cooling helium gas for cooling the wafer 10 from the outside to the upper portion of the lower electrode 310. Do it. Four helium injection holes 321 are formed on the center of the lower electrode 310 to evenly distribute the helium gas supplied through the entire bottom surface of the wafer 10.

A plurality of helium pass lines 323a and 323b are formed on concentric circles having different diameters on upper surfaces of the lower electrodes 310, respectively. Preferably, an outer helium pass line 323b positioned at an outer portion of the lower electrode 310 to cool an edge portion of the wafer 10, and a central portion of the lower electrode 310 disposed on the center of the lower electrode 310. Two of the inner helium passlines 323a are provided to cool the center.

Here, the size of the lower electrode 310 and the position of the helium pass lines 323a and 323b vary depending on the size of the wafer 10 to be mounted, but the lower electrode 310 for the 8-inch wafer which is currently mainstream. For example, it is preferable to have the following size and position. The upper diameter D3 of the 8-inch wafer lower electrode 310 is 201.78 mm which is slightly larger than the diameter of the wafer 10. In addition, the diameter D4 of the concentric circle where the outer helium pass line 323b is located is preferably 170 to 180 mm which is slightly smaller than the diameter of the wafer 10, and the concentric circle where the inner helium pass line 323a is located. It is preferable that diameter D5 is about 80-90 mm which is about half of D4. In particular, the outer helium passline 323b may be located on a concentric circle having a diameter substantially the same as the diameter of the wafer 10 in order to more reliably cool the edge portion of the wafer 10.

As such, since at least two helium passlines 323a and 323b are provided, helium gas is smoothly supplied not only above the center portion of the wafer 10 but also to the edge portion so that the entire portion of the wafer 10 can be uniformly cooled. do.

The helium connection line 322 connects the helium injection hole 321 and the helium pass lines 323a and 323b and is formed on an upper surface of the lower electrode 310. In addition, the helium connection line 322 is radially arranged four cross each other so that helium gas is evenly distributed.

Therefore, the helium gas injected through the helium inlet 321 is evenly distributed by the plurality of helium connection lines 322 and smoothly supplied to the inner helium pass line 323a and the outer helium pass line 323b.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

As described above, since the lower electrode of the etching apparatus according to the present invention includes a plurality of helium pass lines, the cooling helium gas is smoothly supplied to the edge portion as well as the center of the wafer. Therefore, since a uniform cooling effect can be obtained over the entire wafer, and thus the temperature distribution is uniform, the etching rate of each portion of the wafer is uniform, and the phenomenon of burning the photoresist is also prevented. This reduces the difference between the CD and the R-TOX, and thus has an effect of reducing defects and improving yield of the semiconductor device.

Claims (5)

Installed in the chamber of the etching equipment for selectively etching the thin film deposited on the semiconductor wafer by using a plasma, in the lower electrode of the etching equipment mounted on the semiconductor wafer: A helium injection hole formed to penetrate a predetermined portion of the lower electrode in a vertical direction and supply a cooling helium gas for cooling the wafer from the outside to an upper portion of the lower electrode; A plurality of helium passlines formed on concentric circles each having a different diameter on an upper surface of the lower electrode; And And a helium gas supply means for cooling the wafer, wherein the helium connection line is formed on an upper surface of the lower electrode to connect the helium injection hole and the helium pass line. The method of claim 1, The helium passline may include two outer helium passlines positioned at an outer portion of the lower electrode, and two inner helium passlines positioned at the center of the lower electrode. The method of claim 2, And the outer helium passline is located on a concentric circle having a diameter substantially the same as the diameter of the wafer. The method of claim 1, The helium injection hole is a lower electrode of the etching equipment, characterized in that a plurality is formed on the center of the lower electrode. The method of claim 1, The helium connection line is a lower electrode of the etching equipment, characterized in that the four are arranged radially so as to cross each other.