JPH0822982A - Etching condition setting method for dry etching equipment - Google Patents

Abstract

PURPOSE:To make gas flow distribution uniform for material to be etched, by setting the radius of material to be etched, the distance from the electrode center to the farthest etching gas nozzle, the distance between electrodes, and a constant, setting arbitarily the numerical numbers of specified etching, setting specified constants from the numerical numbers, and setting unset numerical numbers. CONSTITUTION:When the radius of material 14 to be etched is R0, the distance from the center of an upper electrode 12 to the outermost etching gas nozzle is R, the distance between the upper electrode 12 and a lower electrode 13 is G, and A is a constant, the numerical numbers of the radius R0 where specified etching is performed, and the distances R, G are arbitrarily set. From the set numerical numbers R0, R and G, the constant A is set by a relational equation R=-AG+R0. This constant A is used, and the unset distance R or G is set by the relational equation. Thereby the distribution of gas flow for the material 14 to be etched can be made almost constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of setting etching conditions for a parallel plate type dry etching apparatus used in a pattern forming process of a wiring material in a semiconductor integrated circuit manufacturing process.

[0002]

2. Description of the Related Art The minimum size of a wiring (usually aluminum) pattern used as a semiconductor integrated circuit has been further increased in density. In order to form these fine patterns, dry etching capable of anisotropic etching is necessary. There are various methods for dry etching, but basically, reactive gas such as halogen is activated in discharge plasma, and these active species and the material to be etched are combined to remove as a volatile substance by exhausting. is there. A surface showing a physical reaction and a surface showing a chemical reaction coexist in the dry etching reaction. The physical reaction is a reaction that is mainly etched by energetic ions, and is characterized by excellent anisotropy but poor sample selectivity. On the other hand, the chemical reaction is mainly due to neutral active species, and although sample selectivity is excellent, isotropic etching is performed.

Which of the above two reactions is dominant depends on the etching method, the gas used and the material to be etched, but a remarkable example is the case of etching an aluminum film. The aluminum film is etched with chlorine gas, but this reaction is a very chemical reaction,
The etching of the aluminum film proceeds even without the help of plasma or even by blowing chlorine gas.

[0004]

By the way, in the case of performing dry etching using a material such as an aluminum film whose chemical reaction is dominant as a material to be etched as described above, the etching rate depends on the distribution of the flow of the etching gas. There is a problem that the distribution changes greatly. Therefore, when using a parallel plate type dry etching device,
When the distance between the pair of opposing electrodes or the dimension of the material to be etched is changed due to other factors, the distribution of the flow of the etching gas changes and the uniformity of the etching rate within the surface of the material to be etched (in-plane The phenomenon that the (uniformity) changes occurs. Therefore, in order to improve the in-plane uniformity of the etching rate, it is necessary to change the etching conditions and the like again after changing the distance between the electrodes or the dimensions of the material to be etched, which is troublesome. It had the drawback of requiring labor.

The present invention has been made in view of the above circumstances, and it is possible to very easily set etching conditions with good in-plane uniformity of etching rate even if the distance between electrodes or the dimension of the material to be etched is changed. The present invention provides a method for setting etching conditions in a parallel plate type dry etching apparatus.

[0006]

In order to achieve the above object, a method for setting etching conditions according to the present invention is a method of setting a radius R0 of a material to be etched in a parallel plate type dry etching apparatus and an electrode having an etching gas ejection hole. When the distance from the center of the electrode to the outermost gas ejection hole is R, the distance between the electrodes is G, and the constant is A, a step of arbitrarily setting the numerical values of R0, R, and G at which predetermined etching is performed,
According to the relational expression of R = -AG + R0 from R0, R, and G, the step of setting the constant A, and when etching a material to be etched having a different radius, one of R and G is arbitrarily set and Or the value of G, different radius R0
And a step of setting an unset R or G by the above relational expression using the set constant A.

[0007]

When the means provided by the present invention is used, the distribution of the gas flow with respect to the material to be etched becomes substantially constant even when the distance between the electrodes or the dimension of the material to be etched is changed.
Good in-plane uniformity of etching speed can be obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. In FIG. 1, 10 is a vacuum container forming an etching chamber, which is grounded, and inside of which (etching chamber 11) is provided a parallel plate-shaped upper electrode 12 and a lower electrode 13 which are opposed to each other on the upper and lower sides. The distance between the electrodes 12 and 13 can be variably set. Reference numeral 14 denotes a material to be etched, which has a resist pattern formed on the surface of a semiconductor wafer having a predetermined diameter, on which an alloy film containing aluminum as a main component which is mainly etched by a chemical reaction is formed. Only one sheet is placed on the lower electrode 13 via (not shown). The lower electrode 13 is electrically insulated from the vacuum container 10 and is connected to a high frequency power source for generating high frequency power via a matching network 15. On the other hand, the upper electrode 12
Is hollow, and its central portion communicates with the etching gas introducing pipe 17 and is grounded. Further, the electrode surface facing the material to be etched 14 has a material to be etched as shown in FIG. A large number of small etching gas ejection holes 18 are arranged in a substantially circular shape so as to oppose to each other. In addition, 19 is a gas exhaust hole of the vacuum container 10, 20 is an inlet / outlet of cooling water for cooling the lower electrode 13, and 21 is a heater coil for heating the vacuum container 10 to a constant temperature. In the dry etching apparatus, the etching gas introduction pipe 17 is provided from the outside of the vacuum container 10.
The etching gas introduced through the above is ejected into the etching chamber 11 from the numerous etching gas ejection holes 18 of the upper electrode 12. Then, high-frequency power from the high-frequency power source 16 is applied between the electrodes 12 and 13 to perform dry etching by the reactive ion etching method.

Here, the radius of the material to be etched 14 is R
0, the radius of the gas ejection hole formation region in the upper electrode 12 (in other words, the distance from the center of the electrode surface of the upper electrode 12 to the outermost gas ejection hole) is R, and the inter-electrode distance is G
Shall be represented by. Now, by fixing G to 70 mm, for example, a semiconductor wafer having an aluminum film formed on the surface and having a diameter of about 127 mm (5 inches) (that is, R0 = 63.5 mm) is used as the material to be etched 14, and the etching gas is used. (For example, when a mixed gas of Bcl3 and Cl2 is used, when R of the upper electrode 12 is changed variously (that is, when a plurality of upper electrodes having different Rs are sequentially replaced and used), FIG. As shown in Fig. 5, the in-plane uniformity of the etching rate was good when R = 39 mm, which gave the relational expression of R = -AG + R0 and calculated that the constant A was about 0.34. It

By obtaining the constant A under the etching condition with good uniformity, the above relational expression is substantially satisfied even when the inter-electrode distance G or the dimension (2R0) of the material to be etched 14 is changed. When R is calculated and the upper electrode having this R is used, the distribution of the gas flow on the material to be etched can be kept constant, so that the in-plane uniformity of the etching rate can be excellently obtained. Therefore, the in-plane uniformity of the etching rate can be satisfactorily obtained with a very simple procedure, that is, without the need for a troublesome procedure for finding the etching condition again. By the way, G
= 100 mm, it becomes R = 63.5.
-0.34 × 100 = 29.5mm is obtained, so R is about 3
Replace with a 0 mm upper electrode. Further, when the wafer is changed from 5 inches to 152.4 mm (6 inches) (that is, when R0 = 76.2 mm is replaced and placed on the lower electrode 13), R = 76 when G = 70 mm. .2-0.3
Since 4 × 70 = 52.4 mm can be obtained, it suffices to replace the upper electrode with R of about 50 mm.

The present invention is particularly effective because it is easy to set the relationship between the wafer and the gas flow constant when the number of semiconductor wafers to be processed at one time is one (so-called single wafer type). Yes, a plurality of gas exhaust holes 1 of the vacuum container 10
When 9 is provided around the lower electrode 13 at a symmetrical position with respect to the lower electrode 13, the gas flow on the material to be etched is averaged, so that the in-plane uniformity of the etching rate is further improved. Become.

[0012]

As described above, according to the method for setting the etching conditions in the parallel plate type dry etching apparatus of the present invention, even if the distance between the electrodes or the dimension of the material to be etched is changed,
It is possible to extremely easily set the etching conditions with good in-plane uniformity of the etching rate.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing a parallel plate type dry etching apparatus according to the present invention.

FIG. 2 is a plan view showing an electrode surface of an upper electrode in FIG. 1 which is taken out and faces an etching target material.

FIG. 3 is a characteristic diagram showing measured data of in-plane uniformity of etching rate when upper electrodes having different radii R of etching gas ejection hole forming regions are used in the apparatus of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vacuum container 11 Etching chamber 12 Upper electrode 13 Lower electrode 14 Etching material 17 Etching gas introduction pipe 18 Etching gas ejection hole 19 Gas exhaust hole

Claims (1)

[Claims] 1. A first electrode on which a material to be etched is placed, and a second electrode facing the first electrode having a large number of etching gas ejection holes formed in a region facing the material to be etched. In a method of setting etching conditions for a predetermined material to be etched in a parallel plate type dry etching apparatus having:
When the distance from the center of the electrode of the second electrode to the outermost etching gas ejection hole is R, the distance between the electrodes is G, and the constant is A, the predetermined etching is performed R0, R , G, the steps of arbitrarily setting the numerical values of G, the step of setting a constant A by the set relational expression of R0, R, G to R = -AG + R0, and the radius of the material to be etched in the predetermined etching. When etching materials with different radii,
One of the values of R or G is arbitrarily set, the value of R or G set arbitrarily, and the different radius R
0, and using the set constant A, a step of setting an unset R or G by the relational expression, the etching condition setting method.