JPH03257824A - Plasma treatment device - Google Patents

Abstract

PURPOSE:To enable production yield to be improved by making a corner of an auxiliary ring to be smooth curved surface for eliminating concentration of electric field at that part and by suppressing generation of dust from the auxiliary ring for compensating electric field. CONSTITUTION:An auxiliary ring for compensating an electric field 6 is provided to prevent turbulence of electric field around a substrate W which is placed on a lower electrode 4. Namely, by placing the substrate W on the lower electrode 4, turbulence of electric field occurs especially at a peripheral part of the substrate and a reaction ion which was dissociated along the electric field enters the substrate so that the auxiliary ring for compensating electric field 6 is provided to prevent uniformity of etching within the substrate from becoming poor. The auxiliary ring 6 becomes thinner from an inside toward an outside and an upper surface is formed in a upward-projecting and gentle curved surface, thus enabling concentration of electric field to be relaxed.

Description

[Detailed description of the invention] 〔overview〕 Regarding plasma processing equipment such as dry erature.

The purpose of this invention is to provide a device that can suppress dust generation from an auxiliary ring for electric field correction provided around the lower electrode, reduce pattern defects of elements, and improve manufacturing yield.

In the processing chamber (1), an upper electrode (5) and an upper electrode (5) are provided.
), and on the surface facing the upper electrode (5), a non-full surface of one side of the substrate to be processed (-) is placed overlappingly, and between it and the upper electrode (5), and a lower electrode (4) that generates plasma by applying an electric field.

It has an auxiliary ring for electric field compensation (6) arranged around the lower electrode (4), and of one side of the auxiliary ring for electric field compensation (6), the surface on which the substrate is stacked is the auxiliary ring for electric field compensation (6). The surface of the lower electrode (4) that is located substantially in the same plane as the surface on which the substrate is placed and on which the substrate is not overlapped gradually moves away from the upper electrode (5) in the direction away from the substrate; The structure is configured to prevent disturbance of the electric field around the substrate.

[Industrial application field]

The present invention relates to a plasma processing apparatus such as a dry erature.

In the manufacturing process of recent miniaturized semiconductor devices, etc.1
The present invention can be used as a device that suppresses dust generation.

In the present invention, an etching apparatus particularly related to dust generation will be explained as an example of a plasma processing apparatus.

[Prior Art] FIG. 3 is a sectional view of a conventional plasma etching apparatus.

In the figure, 1 is a processing chamber, 2 is an etching gas inlet,
3 is an exhaust port, 4 is a lower electrode, 5 is an upper electrode, 7 is a power source,
8 is a conventional electric field compensation auxiliary ring, and W is a substrate to be etched.

22, the electric field compensation auxiliary ring 8 is provided to prevent disturbance of the electric field around the substrate placed on the lower electrode 4.

That is, by placing the substrate on the lower electrode 4, the electric field is disturbed, especially in the peripheral area of the substrate, and reactive ions dissociated along the electric field are incident on the substrate, which deteriorates the uniformity of etching within the substrate. In order to prevent this, an auxiliary ring 8 for electric field compensation is provided.

However, the corners around the electric field compensation auxiliary ring 80 are shaved off by the plasma, causing a single particle.

[Problem to be solved by the invention]

As described above, due to dust generation from the electric field compensation auxiliary ring, fine particles are scattered onto elements formed on a substrate, causing pattern defects and lowering manufacturing yield.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus capable of suppressing dust generation from an auxiliary ring for electric field compensation provided around a lower electrode, reducing pattern defects of elements, and improving manufacturing yield.

(Means for solving the problem) The solution to the above problem is to install an upper electrode (5) in the processing chamber (1).
is arranged to face the upper electrode (5), and a surface of one side of the substrate to be processed (-) that is not the entire surface is placed on the surface facing the upper electrode (5), and the upper electrode (5
) for generating plasma by applying an electric field between the lower electrode (4) and an auxiliary ring (6) for electric field compensation disposed around the lower electrode (4). Of the surfaces of one side of the auxiliary ring (6), the surface on which the substrate is placed is located substantially in the same plane as the surface of the lower electrode (4) on which the substrate is placed, and the surface on which the substrate is placed is placed. This is achieved by a plasma processing apparatus configured to gradually move away from the upper electrode (5) in the direction away from the substrate and prevent disturbance of the electric field around the substrate.

[Effect]

The inventor of the present invention recognized that the cause of dust generation in the device was the wear and tear of the electric field compensation auxiliary ring, and improved the shape of the electric field compensation auxiliary ring.

FIGS. 2(a) and 2(b) are sectional views explaining the present invention in detail.

Figure 2(a) shows the case where the auxiliary ring for electric field compensation of the present invention is used. Since the corners of the auxiliary ring are smooth curved surfaces, there is no concentration of electric field here, and no plasma impact occurs against the auxiliary ring angles. do not have.

FIG. 2(b) shows a case where a conventional electric field compensation auxiliary ring is used, and the electric field is concentrated at the corner of the auxiliary ring, and this portion is scraped by plasma impact.

[Example〕 FIG. 1 is a sectional view illustrating an embodiment of the present invention.

In the figure, 1 is a processing chamber, 2 is an etching gas introduced 0.
3 is an exhaust port, 4 is a lower electrode, 5 is an upper electrode, 6 is an auxiliary ring for electric field compensation of the embodiment, 7 is a power source, and W is a substrate to be etched.

In general, when there is no auxiliary ring, the etching rate is approximately uniform at the center of the substrate, but is higher at the periphery than at the center.

Therefore, by inserting an auxiliary ring, the etching speed is made uniform all the way to the periphery.

The diameter of the auxiliary ring can be determined as appropriate experimentally.

The auxiliary ring 6 in this example has an inner diameter of 140 mm, an outer diameter of 200 mm, and a thickness of 12+n+, while the diameter of the lower electrode is 140 m5.
Alumite treatment was performed on the surface of 5 using the aluminum (^l) ring of a.

The feature of this embodiment is that the ring becomes thinner from the inside to the outside, and the upper surface is formed into an upwardly convex gently curved surface to alleviate the concentration of the electric field.

Next, a silicon nitride (SiJ4) film was etched using the apparatus of the example under the following conditions.

Etching conditions Etching gas: CFa10x/CBrF5 gas pressure 340 Torr Etching power density: 300 W/6 inch substrate As a result, the etching rate was ±3% within the substrate.

Further, as a result of microscopic observation of many samples of the substrate surface after etching, no dust was observed at all.

Furthermore, as a result of continuing etching for a long period of time, no wear and tear on the auxiliary ring was observed.

〔Effect of the invention〕

As explained above, according to the present invention, it was possible to suppress dust generation from the electric field correction auxiliary ring provided around the lower electrode, reduce pattern defects of elements, and improve manufacturing yield.

[Brief explanation of drawings]

FIG. 1 is a sectional view illustrating a plasma etching apparatus according to an embodiment of the present invention. FIGS. 2(a) and 2(b) are sectional views illustrating the present invention in detail in comparison with a conventional example. FIG. 3 is a sectional view of a conventional plasma etching apparatus. In fig. 1 is the etching room. 2 is the etching gas inlet. 3 is the exhaust port. 4 is the lower electrode. 5 is the upper electrode. 6 is an auxiliary ring for electric field compensation in the embodiment. 7 is the power supply. W is the substrate to be etched.

Claims (1)

[Scope of Claims] In the processing chamber (1), an upper electrode (5) is disposed to face the upper electrode (5), and a surface to be treated is disposed to face the upper electrode (5). A lower electrode (W) on which the surface of one side of the substrate (W) that is not the entire surface is placed on top of the other, and which generates plasma by applying an electric field between it and the upper electrode (5).
4), and an auxiliary ring for electric field compensation (6) disposed around the lower electrode (4), and one side of the auxiliary ring for electric field compensation (6) on which the substrate is overlapped. The surface is located approximately in the same plane as the surface of the lower electrode (4) on which the substrate is placed, and the surface on which the substrate is not placed is gradually parallel to the upper electrode (5) in the direction away from the substrate. ) and configured to prevent disturbance of the electric field around the substrate.