JPH0845910A - Plasma treatment device - Google Patents

Abstract

PURPOSE:To enhance the uniformity of treatment conducted on various conditions of the etching such as plasma etching for example. CONSTITUTION:In an etching device on which an upper electrode 2, whereon a plurality of gas jetting holes 5 are provided on the surface, and a lower electrode, where the substrate 9 to be etched is placed, are provided in a chamber 1, and gas is fed into the chamber 1 through the gas jetting holes 5 of the upper electrode 2 from a gas feeding chamber 4, a regulating plate 7, having a plurality of apertures 8 corresponding to the gas jetting holes 5 of the upper electrode 2, is arranged inside the gas feeding chamber 4 which comes in contact with the upper electrode 2. By adjusting the superposition between the apertures 8 and the gas jetting holes 5 by shifting the regulating plate 7, the aperture area of the gas jetting holes 5 is varied between the center part and the circumferential part, the density of etching gas is adjusted, and the planar uniformity of etching speed is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus such as a dry etching apparatus or a CVD apparatus which uses plasma, and more particularly to a gas ejection hole formed in an electrode of the plasma processing apparatus.

[0002]

2. Description of the Related Art FIG. 6 is a schematic sectional view of a conventional general parallel plate type dry etcher. In the chamber 1, two electrodes, that is, an upper electrode 2 and a lower electrode 6, are arranged so as to face each other. Usually, when etching, a substrate 9 to be etched such as a wafer is placed on the lower electrode 6, and a large number of holes are opened from the gas supply device 10 to the gas supply pipe 3 and the gas supply chamber 4 and the surface of the upper electrode 2. Etching gas is introduced into the chamber 1 through the gas ejection hole 5 and the upper electrode 2 or the lower electrode 6 is oscillated by RF oscillation by a high frequency power supply device (not shown) to discharge the etching gas into plasma.

Further, as described in JP-A-1-149964 and JP-A-3-122285, a plurality of gas ejection holes formed in a conventional upper electrode are
The upper electrode was formed so as to increase in size from the central portion toward the peripheral portion.

[0004]

Generally, the etching rate tends to gradually increase or decrease from the central portion to the peripheral portion of the substrate 9 to be etched. That is, when a contour line of the etching rate is drawn, it becomes a concentric circle centered on the substantially central portion. Therefore, in order to improve the in-plane uniformity of the etching rate, the difference between the central portion and the peripheral portion may be reduced.

For that purpose, the size of the gas ejection hole 5 of the upper electrode 2 may be changed near the central portion and the peripheral portion to change the etching gas concentration distribution in the chamber 1. That is, when the etching rate in the vicinity of the central portion is reduced, the opening diameter of the gas ejection holes 5 is made smaller in the central portion than in the peripheral portion, and conversely, when the etching rate in the peripheral portion is reduced, The opening diameter of the ejection hole 5 may be smaller in the peripheral portion than in the central portion.

However, the etching rate of the etching gas, RF
Since it varies depending on conditions such as power and pressure, it has been difficult to improve uniformity under various conditions with the conventional gas ejection holes 5 having a fixed size.

Further, each gas ejection hole of the upper electrode as described in JP-A-1-149964 and JP-A-3-122285 has conditions such as etching rate, etching gas species, RF power and pressure. Therefore, it is difficult to improve the uniformity with respect to the above-mentioned conditions with the gas ejection holes having such a fixed size.

Therefore, an object of the present invention is to provide a plasma processing apparatus capable of enhancing the uniformity of processing under any of various conditions in plasma processing.

[0009]

In order to achieve the above object, the present invention provides a first electrode on which a plurality of gas ejection holes are dispersedly provided on the surface and an object to be processed. A plasma processing apparatus provided with a gas supply unit that is provided in a vacuum chamber so as to face the second electrode, and that supplies gas from the gas supply chamber to the vacuum chamber through gas ejection holes of the first electrode. An adjusting plate which is provided so as to overlap with the first electrode and closes at least a part of the gas ejection hole,
An aperture area varying means for varying the aperture area of the gas ejection hole by adjusting the overlap between the gas ejection hole and the adjusting plate.

The opening area changing means is the first area changing means.
When the gas ejection holes arranged at a predetermined distance from the center of the electrode toward the outer end are used as reference holes, and inside the reference holes when the area of the gas ejection holes outside the reference holes increases or decreases. So that the area of the gas ejection holes of
The adjusting plate may be controlled.

[0011]

According to the present invention configured as described above, the first
By adjusting the overlap between the plurality of gas ejection holes of the electrode and the adjusting plate that closes at least a part of each of these gas ejection holes, the opening area of the gas ejection holes in the central portion and the peripheral portion of the vacuum chamber is adjusted. The relative size of is variable. The adjustment plate has an adjustment window of, for example, an equilateral triangle shape, an isosceles triangle shape, a rectangular shape, a square shape, or the like so that the opening area of the gas ejection hole can be changed by parallel movement or rotation with respect to the first electrode. Good to have.

Therefore, for example, in etching, under the condition that the etching rate in the central portion tends to be smaller than that in the peripheral portion, the opening area of the gas ejection holes in the central portion is adjusted to be larger than that in the peripheral portion. By adjusting the plate,
It is possible to increase the etching gas density in the central portion and bring the etching rate in the central portion closer to that in the peripheral portion, thereby enhancing the in-plane uniformity of the etching rate. Conversely, under conditions where the etching rate in the peripheral area tends to be lower than in the central area, the etching gas density in the peripheral area is increased by adjusting the adjustment plate in reverse, resulting in in-plane uniformity of the etching rate. Can be increased.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the plasma processing apparatus according to the present invention is applied to a dry etching apparatus will be described below with reference to FIGS. FIG. 1 is a schematic cross-sectional view of an etching apparatus in an embodiment, and FIG. 2 is a plan view of essential parts showing a positional relationship between an upper electrode and an adjusting plate.

First, in FIG. 1, an upper electrode 2 and a lower electrode 6 are installed in a chamber 1 so as to face each other. In this figure, the electrical connection of the power supply device is omitted. The etching gas first passes from the gas supply device 10 through the gas supply pipe 3, then through the gas supply chamber 4 on the back surface of the upper electrode 2, and then through a plurality of gas ejection holes 5 provided on the surface of the upper electrode 2. And is introduced into the chamber 1. A substrate 9 to be etched such as a wafer is placed on the lower electrode 6.

Next, as shown in FIGS. 1 and 2, an adjusting plate 7 is arranged inside the gas supply chamber 4 in contact with the upper electrode 2. A plurality of openings 8 are formed in the adjustment plate 7, and these openings 8 are formed in the gas ejection holes 5 of each of the upper electrodes 2.
Corresponding to the above, it serves as an adjusting window for increasing or decreasing the opening area of each gas ejection hole 5. In FIG. 2, the positions of A, B, C, D, and E where the gas ejection holes 5 of the upper electrode 2 and the opening portions 8 of the adjusting plate 7 overlap are arranged in order from the peripheral portion to the central portion of the chamber 1. ing. The adjusting plate 7 can be displaced in parallel with the upper electrode 2 in the direction of the arrow in FIG.

FIGS. 3 (a) to 3 (e) are AE shown in FIG.
7A and 7B show how the gas ejection holes 5 and the opening portions 8 overlap each other. The open areas of the gas ejection holes 5 of the upper electrode 2 are 51, 52 and 5 on A, B, C, D and E, respectively.
3, 54, and 55, which are all squares of the same size. On the other hand, the aperture area of the aperture portion 8 of the adjusting plate 7 is A, B,
81, 82, 83, 84, 85 respectively on C, D, E, and the base of the isosceles triangle gradually decreases from the peripheral portion to the central portion, becomes a rectangle on the way, and then in the opposite direction. It becomes an isosceles triangle and the base gradually increases.

The overlapping region of these aperture regions is indicated by the hatched portion in FIG. That is, the gas flows in the area where the holes are overlapped in the shaded area. In the state of FIG. 3, the area of the shaded area, that is, the area of the openings is in the order of A>B>C>D> E, and the peripheral portion in the chamber 1 has a higher etching gas density than the central portion.

When the adjusting plate 7 is moved to the left here,
At a certain point, the opening areas of A, B, C, D, and E become almost the same, and when the etching rates are not so different between the central portion and the peripheral portion, it may be adjusted to this state.

When the etching rate in the central portion is smaller than that in the peripheral portion, when the adjusting plate 7 is further shifted to the left side, the size of the opening area is in the order of E>D>C>B> A. Is corrected so that the etching gas density becomes higher than that of the peripheral portion, and the in-plane uniformity of the etching rate can be improved.

For example, when the isosceles triangular aperture area 82 of the adjusting plate 7 shown in FIG. 3B is shifted to the left, the gas ejection hole G (hatched portion) is opened as shown in FIG. 4A. The area becomes smaller, and when it is shifted to the right, the opening area of the gas ejection hole G becomes larger as shown in FIG. 4 (b).

FIG. 5A is a plan view of the upper electrode. In FIG. 5A, r = 0 is the center of the upper electrode 2 and R is the radius of the upper electrode 2. In this embodiment, r = 0.5R
At the boundary, the opening area of the gas ejection hole 5 of the upper electrode 2 is adjusted by the opening portion 8 (adjustment window) provided in the adjustment plate 7.

In FIG. 5B, the opening 8 of the adjusting plate 7
When is an isosceles triangle, each open area S is represented by S = h (h + 2i) tan θ. When the apertures 8 are each an isosceles triangle as in this equation, the aperture area is determined by an angle θ which is half the apex angle of the isosceles triangle.

The opening area N at a distance (r = 0.5R) that is half the radius R from the center (r = 0) is the lateral length h of the gas ejection hole 5 of the upper electrode 2 and the adjusting plate. 7 hole 8
By multiplying it by the vertical length j of the rectangle, N = h × j.

Therefore, the opening area of the gas ejection hole 5 is 0 ≦.
In the range of r <0.5R and 0.5R <r ≦ R, S = h
(H + 2i) tan θ (where θ has different angles depending on r), and when r = 0.5R, N = h ×
It is represented by j.

In this embodiment, the gas ejection hole 5 at r = 0.5R is used as a reference hole that overlaps the rectangular opening 8, and the gas ejection holes 5 on the outer and inner sides of the reference hole are: By stacking isosceles triangular opening portions 8 in opposite directions and different vertex angles in order, the opening area of the gas ejection holes 5 increases or decreases when the adjusting plate 7 is displaced.
Thereby, the etching gas density between the central portion and the peripheral portion can be adjusted more efficiently.

As described above, in the present embodiment, the adjustment plate 7 was slid to change the opening area of the gas ejection hole 5 of the upper electrode 2, but the adjustment plate is rotated to change the opening area of the gas ejection hole. The opening portion of the adjustment plate may be provided along the rotational direction so that the adjustment can be made. The shape of the aperture of the adjusting plate of the present embodiment is an isosceles triangle and a rectangle, but the shape is not particularly limited to these shapes, and for example, a looped shape such as a curved line is overlapped with the gas ejection hole of the electrode. The shape and size may be changed so that the opening area can be varied and the increase or decrease of the opening area can be reversed. That is, the opening area varying means referred to in the present invention is means for changing the opening area of the gas ejection holes by adjusting the overlap between the gas ejection holes of the electrode and the adjusting plate. The configuration includes the shape and size of the portion, and this configuration can be variously modified.

Although the etching apparatus has been described in the present embodiment, the in-plane uniformity of the deposition rate can be improved by using the same configuration also in the case of a CVD apparatus for depositing a film.

[0028]

As described above, according to the present invention,
Even if the tendency of the difference in etching rate between the central portion and the peripheral portion is different due to various conditions during the process using plasma, for example, etching, the opening area of the gas ejection holes of the electrode is different from that of the central portion and the peripheral portion. Since it can be relatively changed between the two, the uniformity of processing can be improved by adjusting the etching gas density.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an etching apparatus in an embodiment of a plasma processing apparatus according to the present invention.

FIG. 2 is a plan view of an essential part showing a positional relationship between an upper electrode and an adjusting plate in the above-mentioned embodiment.

FIG. 3 (a) to (e) in FIG.
FIG. 7 is an enlarged plan view showing details of portions A to E of FIG.

FIG. 4 is an enlarged plan view for explaining the variable opening area of FIG. 3B in the above embodiment.

5A is a plan view of an upper electrode in the above embodiment, FIG. 5B is an enlarged plan view illustrating an opening area when the opening is an isosceles triangle, and FIG. It is an enlarged plan view explaining the aperture area in the case of a rectangle.

FIG. 6 is a schematic sectional view of a conventional etching apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 chamber 2 upper electrode 3 gas supply pipe 4 gas supply chamber 5 upper electrode gas ejection holes 51, 52, 53, 54, 55 hole region of gas ejection hole 6 lower electrode 7 adjusting plate 8 adjusting plate opening 81 , 82, 83, 84, 85 Opening area of opening 9 Substrate to be etched 10 Gas supply device

Claims (2)

[Claims] 1. A gas chamber is provided so that a first electrode having a plurality of gas ejection holes dispersedly provided on a surface thereof and a second electrode on which an object to be processed is placed face each other, and a gas is provided. In a plasma processing apparatus comprising a gas supply means for supplying a gas from a supply chamber into the vacuum chamber via a gas ejection hole of the first electrode, the plasma treatment apparatus is provided so as to overlap the first electrode, An adjusting plate for closing at least a part of the adjusting plate, and an opening area changing means for changing the opening area of the gas discharging hole by adjusting the overlap between the gas discharging hole and the adjusting plate. And a plasma processing apparatus. 2. The opening area varying means has a gas ejection hole located at a predetermined distance from the center of the first electrode toward the outer end as a reference hole and is located outside the reference hole. 2. The plasma processing apparatus according to claim 1, wherein the adjusting plate is controlled so that, when the area of the gas ejection holes increases or decreases, the area of the gas ejection holes inside the reference hole decreases conversely. .