JP2002025984A - Shower plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a shower plate incorporating electrodes for semiconductor manufacturing device to uniformly supply a gas into a chamber. SOLUTION: In a semiconductor manufacturing device, a shower plate used to supply gas into the chamber is provided with grid-shaped grooves having a width of 0.3-2 mm and a depth of >=3 mm, and a plurality of gas blow-out ports are formed in the grooves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shower for an electrode cover or the like including a plasma electrode having a gas supply nozzle structure in an apparatus for introducing a gas into a chamber and forming and etching a wafer on a wafer in semiconductor manufacturing. It is about a plate.

[0002]

2. Description of the Related Art In FIG.
Reference numeral 02 denotes a shower plate including an upper electrode, and has a hollow plate shape. A plurality of gas ejection holes (not shown) that open toward the reaction space 109 are formed on the surface of the shower plate 102 facing the sample stage 108. This gas ejection hole communicates with the gas introduction pipe 112 through a passage.

[0003] A shower plate 102 in a chamber 101 and a reaction space 109 between a sample table 108.
The surface of the wafer 107 placed on the sample stage 108 (one electrode) is subjected to a plasma surface treatment, such as forming a film on the surface of the wafer 107 by applying a high voltage while causing the reactive gas 103 to flow therethrough.

[0004] Here, a reactive gas 103 is introduced from a gas introduction pipe 112 to a shower plate 102 including an upper electrode, and the reactive gas 103 is supplied from the shower plate 102.
Is injected, the reactive gas 103 spreads in the reaction space 109.

Further, as shown in FIG. 6, a concentric, spiral, or knurled groove 105 is formed on the surface of the shower plate 102 including the electrode facing the sample stage 108.
Is formed, and the protruding portion 106 is formed.
Has proposed a configuration in which a plurality of gas ejection holes 111 opening toward a gap between the shower plate 102 and the sample table 108 and a passage communicating the gas ejection holes 111 with a hollow portion are formed (utility model). Registered Number 2567888
Reference).

[0006]

The conventional shower plate 102 shown in FIG. 7 cannot be used due to a problem such as the degree of vacuum in the chamber 101 if the gas ejection hole 111 for introducing the reaction gas 103 is large. In order to discharge the reaction gas 103 as uniformly as possible into the inside
A large number of small gas ejection holes 111 having a diameter of 2 to 1.0 mm were machined and formed.

However, since a large number of small gas ejection holes 111 are machined so as to introduce the reaction gas 103 into the chamber 101 as uniformly as possible, the reaction gas 103 is provided between each of the gas ejection holes 111. It was not introduced, and the diffusion into the chamber 101 was not completely uniform.

[0008] Also, here, although gradually, a wafer 107 having a diameter of 12 inches is flowing.
The uniformity of the film quality in the 07 plane has been required.

When the reaction area of the wafer 107 increases, the reaction gas 10 flowing to the center of the reaction space 109
3, the gas distribution becomes non-uniform.

[0010] Therefore, in the CVD method, there is a problem in how the film is formed and its thickness, and in an etching apparatus, the etching rate is a problem. In such a characteristic, the conventional supply part of the reactive gas 103 such as the shower plate 102 has a problem in that the reactive gas 103 is uniformly supplied to all positions in the chamber 101.

Further, in the shower plate 102 shown in FIG. 6, the gas ejection holes 111 are formed on concentric convex portions, but this has little effect in terms of gas diffusion.

When viewed from the space below the shower plate 102, the shape shown in FIG. 6 merely flows gas downward from the gas holes, so that there is not much difference from the case where a flat shower plate is used, and the gas turns uniformly. The difficulty was the same.

The present invention has been made in order to solve the above-mentioned problems, and an electrode for plasma which can make the distribution of the supply gas amount in the reaction space 109 uniform and enables high quality surface treatment is provided. An object of the present invention is to provide a shower plate structure including the same.

[0014]

In view of the above, the present inventor has studied a structure capable of uniformly feeding gas into the chamber, and changed the structure of the gas ejection holes of the shower plate including the electrodes. We paid attention to.

That is, in a semiconductor manufacturing apparatus using plasma, a shower plate for supplying a gas is provided with a lattice-like groove having a width of 0.3 to 2 mm and a depth of 3 mm or more, and a plurality of gas jets are formed in the groove. A hole is formed.

In the shower plate of the present invention, the grooves have a triangular or quadrangular lattice shape, and the gas ejection holes are located at intersections of the lattice. As a result, the supplied reaction gas diffuses along the lattice-shaped grooves and is uniformly fed into the reaction space, and the supply gas amount distribution in the reaction space can be made uniform, so that the surface treatment of the wafer is made more uniform. Can be done.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 5, an etching apparatus which is an example of a semiconductor manufacturing apparatus has a chamber 1, a shower plate 2 covering a discharge surface of an electrode, and a surface of the shower plate 2 facing the sample table 8. Are formed with a plurality of gas ejection holes 11 opening toward the reaction space 9.
Further, the gas ejection hole 11 communicates with the gas introduction pipe 12 through a passage.

Then, a high voltage is applied while flowing the reactive gas 3 into the reaction space 9 between the shower plate 2 and the sample table 8 in the chamber 1 to generate a glow discharge, and the sample table 8 (one electrode) Plasma surface treatment such as forming a film on the surface of the wafer 7 placed thereon is performed.

Here, the reactive gas 3 is supplied from the gas introduction pipe 12 to the shower plate 2 forming the upper electrode, and when the reactive gas 3 is jetted from the shower plate 2, the reactive gas 3 enters the reaction space 9. Is spreading.

FIG. 1 shows the structure of the shower plate 2 of the present invention.
This will be described with reference to FIGS. As shown in FIG. 1A, in the shower plate 2, reference numeral 11 denotes a gas ejection hole for supplying the reaction gas 3, and reference numeral 5 denotes a lattice-like groove.

FIG. 1B is a sectional view of the shower plate 2 taken along line X-X.
In the sectional view along the line, a lattice-shaped groove 5 is provided, and a gas ejection hole 11 is formed in the groove 5. Explaining the structure behind the shower plate 2, reference numeral 17 denotes an electrode, which is provided with a hole at the same position as the gas ejection hole 11 and communicates with the gas ejection hole 11. Reference numeral 18 denotes a conduction line connecting the electrode 17 to a high-frequency power supply. 12 is a gas introduction pipe, 13 is a high frequency shield provided on the back of the gas distribution plate 16 and around the gas introduction pipe 12,
Reference numeral 14 denotes a high-frequency insulated vacuum seal embedded between the high-frequency shield 13 and the gas introduction pipe 12, and 15 denotes an insulator provided between the gas dispersion plate 16 and the high-frequency shield 13.

According to the present invention, the shape of the gas passage of the shower plate 2 including the electrodes used in the semiconductor manufacturing apparatus such as the CVD apparatus and the etching apparatus is set such that the grid-shaped grooves 5 are provided on one surface with respect to the gas ejection holes 11. Chamber 1
The reaction gas 3 was uniformly supplied to the inside of the wafer 7 to enable a uniform surface treatment within the surface of the wafer 7.

How uniformly the reaction gas 3 is
As for the point of flowing the gas, the more the number of the gas ejection holes 11 is increased, the more uniformly the gas can be supplied. On the other hand, however, it becomes difficult to control the pressure in the chamber 1. Therefore, the supply amount of the reaction gas 3 is kept the same as the conventional one, and the lattice-shaped grooves 5
It is provided with.

As shown in detail in FIGS. 2A, 2B and 3A and 3B, a triangular or quadrangular lattice-shaped groove 5 is formed in the shower plate. By forming the gas ejection holes 11 so as to overlap the intersections of the lattices in the grooves 5, the processing can be facilitated, and the supplied reaction gas flows along the lattice-like grooves 5 to form 4 (square).
Since the gas is diffused in the directions of ６6 (triangles) and is uniformly fed, and the gas concentration in the chamber 1 can be made uniform, the surface treatment of the wafer can be performed more uniformly.

In particular, due to the lattice shape, the reaction gas 3 supplied from the shower plate 2 diffuses in the horizontal direction through the groove 5 as compared with the conventional example shown in FIG. A more uniform gas supply can be obtained.

Here, the width W of the groove 5 is preferably 0.3 to 2 mm. This is because if the width W is less than 0.3 mm, processing becomes extremely difficult, and if the width W exceeds 2 mm, a sufficient diffusion effect cannot be obtained.

The depth T of the groove 5 is preferably 3 mm or more. This is because a sufficient diffusion effect cannot be obtained if the groove depth T is less than 3 mm.

More preferably, the depth T is set to a half of the thickness up to the shower plate, that is, the depth T reaches the gas ejection hole 11 described above. The reaction gas 3 that has entered through the gas ejection holes 11 travels along the holes 4 in the same way as the conventional shower plate 2 up to half the thickness of the shower plate 2. However, when it reaches half, it diffuses along the groove 5.

Also, the lattice shape of the groove 5 may be a polygon of 5 or more, but there is no great difference from a triangle or a quadrangle. A triangular or quadrangular shape is preferred because it causes a rise.

A preferable range of the pitch of the gas ejection holes 11 may be a pitch having a total area which is most suitable when the apparatus is operated, and is about 3 to 20 mm.

As a result, the reaction gas 3 can be supplied into the chamber 1 from a relatively wide range of the shower plate 2, and a uniform surface treatment on the wafer 7 can be performed.

The material of the shower plate 2 is preferably a ceramic containing alumina, aluminum nitride, silicon nitride or the like as a main component, in consideration of fluorine-based and chlorine-based gases used for wafer processing.

Next, a method for manufacturing the shower plate of the present invention will be described.

First, a plate-like body of the above ceramics is prepared,
As shown in FIGS. 1 (A) and 1 (B), the gas injection holes 11 of φ0.3 mm to φ2 mm are formed without being penetrated from the surface of the shower plate 2 opposite to the wafer 7 and are stopped at half the thickness. Next, a lattice-shaped groove 5 having a groove width W of 0.3 to 2 mm and a depth T of 3 mm or more is formed on the surface of the shower plate 2 on the wafer 7 side.
Is processed so that the gas ejection hole 11 overlaps the intersection of the lattice in the groove 5, and the gas ejection hole 11 may be communicated with the groove 5.

Then, an electrode 17 having a hole previously formed at the same position as the gas ejection hole 11 is overlapped and fixed on the surface of the shower plate opposite to the wafer 7. It is not always necessary to form a hole for the electrode 17, and a gap may be provided between the electrode 17 and the surface of the gas ejection hole 11 to supply the reaction gas 3.

The method for processing the gas ejection holes 11 and the grooves 5 is basically for processing a sintered body. First, the gas ejection holes 11 are formed by a drill, and the grooves 5 are processed by a milling machine. If the gas ejection holes 11 are relatively large,
Since the gas ejection holes 11 can be processed by a grinding center, the grooves 5 are processed by a surface grinder. In addition, the gas ejection holes 11 are ultrasonically processed. The groove 5 can be processed by blasting.

[0038]

EXAMPLES (Experimental Example 1) The etching rate on the wafer 7 was investigated with the etching apparatus shown in FIG. First, in the chamber 1, grooves 5 having various groove widths W and depths T were machined into a triangular lattice shape on the surface, and a shower plate 2 in which the gas supply holes 4 were located at intersections of the lattices was installed.
As a comparative example, a sample N in which the groove 5 was not formed and only the through hole was provided
o. 1 and the conventional sample No. 1 shown in FIG. 9 were prepared.

From the shower plate 2 to the chamber 1
When the reaction gas 3 is supplied into the inside, the supplied reaction gas 3 is turned into plasma, and fine processing is performed on the surface of the wafer 7. This time, by changing the structure (width, depth) of the groove 5 of the shower plate 2, the central portion 7a of the wafer 7 shown in FIG.
The degree of difference between the etching rate and the outer peripheral portion 7b was compared, and the in-plane uniformity of each product was investigated. That is, the weight loss of the central portion 7a and the outer peripheral portion 7b of the wafer 7 before and after the treatment is measured, and the etching rate of the outer peripheral portion 7b is determined when the etching rate of the central portion 7a is set to 1. Was. Table 1 shows the results.

In Table 1, the sample No.
No. 1 and the shape, width W, and depth T of the groove were Nos. 2,
In Nos. 5, 8, and 9, the outer peripheral portion etching rate was significantly lower than 0.92, which was extremely poor in uniformity. In 3, 4, 6, and 7, it can be seen that the uniformity is improved with the outer peripheral portion etching rate being 0.95 or more.

In the above embodiment, the shower plate 2
Used a groove formed on the surface thereof in a triangular lattice shape, but the same effect can be obtained by forming the groove 5 using a groove processed in a square lattice shape. .

[0042]

[Table 1]

[0043]

According to the present invention, a shower plate for supplying gas in a semiconductor manufacturing apparatus using a plasma is provided with a lattice-like groove having a width of 0.3 to 2 mm and a depth of 3 mm or more, and a plurality of gases are provided in this groove. By forming the ejection holes, in-plane uniformity of etching and film formation on the wafer surface is remarkably improved, and ultimately a great effect can be obtained in improving the yield of a single chip.

Further, since the groove has a triangular or quadrangular lattice shape and the gas ejection holes are located at the intersections of the lattice, the lattice shape can be easily processed, and the gas concentration in the chamber can be made uniform. Can be further enhanced.

As described above, according to the present invention, the distribution of the supply gas amount in the reaction space can be made uniform, and a high-quality surface treatment can be performed even on a wafer having a large processing area.

[Brief description of the drawings]

FIG. 1A is a plan view showing a shower plate of the present invention, and FIG. 1B is a sectional view taken along line XX.

FIG. 2A is an enlarged plan view showing an example of the vicinity of gas ejection holes in a shower plate of the present invention, and FIG.
FIG. 4 is an enlarged cross-sectional view taken along line -Y.

3A is an enlarged plan view showing another example of the vicinity of the gas ejection holes in the shower plate of the present invention, and FIG. 3B is an enlarged cross-sectional view taken along the line ZZ.

FIG. 4 is a schematic view showing an example of a sample wafer.

FIG. 5 is a schematic diagram showing an example of an etching apparatus provided with a shower plate of the present invention.

FIG. 6 is an enlarged plan view showing an example of the vicinity of gas ejection holes in a conventional shower plate.

FIG. 7 is a schematic diagram showing an example of an etching apparatus provided with a conventional shower plate.

[Explanation of symbols]

1, 101: chamber 2, 102: shower plate 3, 103: reaction gas 5, 105: groove W: width T: depth 106: protrusion 7, 107: wafer 7a: center 7b: outer periphery D: diameter 8, 108: sample stage 109: reaction space 111: gas ejection hole 112: gas introduction tube 13: high frequency shield 14: vacuum seal 15: insulator 16: glass dispersion plate 17: electrode 18: conduction wire

Claims (2)

[Claims] 1. A shower plate for supplying gas in a semiconductor manufacturing apparatus using plasma,
Equipped with a grid-like groove with a width of 0.3 to 2 mm and a depth of 3 mm or more,
A shower plate comprising a plurality of gas ejection holes formed in the groove. 2. The shower plate according to claim 1, wherein the grooves have a triangular or quadrangular lattice shape, and the gas ejection holes are located at intersections of the lattices.